bims-amsmem 2022-04-03 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022‒04‒03
34 papers selected by
Dipsikha Biswas, Københavns Universitet

Targeting AMPK signaling in ischemic/reperfusion injury: From molecular mechanism to pharmacological interventions.
Solasonine relieves sevoflurane-induced neurotoxicity via activating the AMP-activated protein kinase/FoxO3a pathway.
Atrial Lesions in a Pedigree With PRKAG2 Cardiomyopathy: Involvement of Disrupted AMP-Activated Protein Kinase Signaling.
Metformin attenuates early brain injury after subarachnoid hemorrhage in rats via AMPK-dependent mitophagy.
ETC-1002 Attenuates Porphyromonas gingivalis Lipopolysaccharide-Induced Inflammation in RAW264.7 Cells via the AMPK/NF-κB Pathway and Exerts Ameliorative Effects in Experimental Periodontitis in Mice.
Antidiabetic efficacy of Trifolium alexandrinum extracts hesperetin and quercetin in ameliorating carbohydrate metabolism and activating IR and AMPK signaling in the pancreatic tissues of diabetic rats.
The Activation of AMPK/NRF2 Pathway in Lung Epithelial Cells Is Involved in the Protective Effects of Kinsenoside on Lipopolysaccharide-Induced Acute Lung Injury.
MD2 deficiency prevents high-fat diet-induced AMPK suppression and lipid accumulation through regulating TBK1 in non-alcoholic fatty liver disease.
Hepatocyte-specific eNOS deletion impairs exercise-induced adaptations in hepatic mitochondrial function and autophagy.
IMM-H007 attenuates isoprenaline-induced cardiac fibrosis through targeting TGFβ1 signaling pathway.
Sleeve Gastrectomy-Induced AMPK Activation Attenuates Diabetic Cardiomyopathy by Maintaining Mitochondrial Homeostasis via NR4A1 Suppression in Rats.
Fasting potentiates insulin-mediated glucose uptake in rested and prior-contracted rat skeletal muscle.
Metformin alleviates dexamethasone-induced apoptosis by regulating autophagy via AMPK/mTOR/p70S6K in osteoblasts.
Lipid metabolism disorders and lipid mediator changes of mice in response to long-term exposure to high-fat and high sucrose diets and ameliorative effects of mulberry leaves.
Activation of 20-HETE Synthase Triggers Oxidative Injury and Peripheral Nerve Damage in Type 2 Diabetic Mice.
Valdecoxib attenuates lipid-induced hepatic steatosis through autophagy-mediated suppression of endoplasmic reticulum stress.
A review of autophagy mechanism of statins in the potential therapy of Alzheimer's disease.
Effects of caloric overload before caloric restriction in the murine heart.
2,3,4',5‑Tetrahydroxystilbene‑2‑O‑β‑D‑glucoside ameliorates gentamicin‑induced ototoxicity by modulating autophagy via Sesn2/AMPK/mTOR signaling.
Mechanism of N-Methyl-N-Nitroso-Urea-Induced Gastric Precancerous Lesions in Mice.
The mitophagosome, a novel ultrastructure of mitophagy in the alcoholic steatohepatitis mouse model: a transmission electron microscope study.
Neuroprotective effect of liraglutide in an experimental mouse model of multiple sclerosis: role of AMPK/SIRT1 signaling and NLRP3 inflammasome.
Mitochondrial dynamics and biogenesis indicators may serve as potential biomarkers for diagnosis of myasthenia gravis.
Adiponectin receptor agonist ameliorates cardiac lipotoxicity via enhancing ceramide metabolism in type 2 diabetic mice.
Cajaninstilbene Acid Ameliorates Acetaminophen-Induced Liver Injury Through Enhancing Sestrin2/AMPK-Mediated Mitochondrial Quality Control.
Dapagliflozin as an autophagic enhancer via LKB1/AMPK/SIRT1 pathway in ovariectomized/D-galactose Alzheimer's rat model.
Acacetin attenuates diabetes-induced cardiomyopathy by inhibiting oxidative stress and energy metabolism via PPAR-α/AMPK pathway.
Peroxisome Proliferator Activated Receptor Gamma Coactivator-1 Alpha: A Double-Edged Sword in Prostate Cancer.
The enhanced mitochondrial dysfunction by cantleyoside confines inflammatory response and promotes apoptosis of human HFLS-RA cell line via AMPK/Sirt 1/NF-κB pathway activation.
β-Hydroxyisovalerylshikonin regulates macrophage polarization via the AMPK/Nrf2 pathway and ameliorates sepsis in mice.
Pretreatment of hydroethanolic extract of Dillenia indica L. attenuates oleic acid induced NAFLD in HepG2 cells via modulating SIRT-1/p-LKB-1/AMPK, HMGCR & PPAR-α signaling pathways.
Prooxidant activity-based guideline for a beneficial combination of (-)-epigallocatechin-3-gallate and chlorogenic acid.
MiR-21 modulates proliferation and apoptosis of human airway smooth muscle cells by regulating autophagy via PARP-1/AMPK/mTOR signalling pathway.
Cholesterol sensor SCAP contributes to sorafenib resistance by regulating autophagy in hepatocellular carcinoma.

Cell Signal. 2022 Mar 28. pii: S0898-6568(22)00084-5. [Epub ahead of print] 110323

Targeting AMPK signaling in ischemic/reperfusion injury: From molecular mechanism to pharmacological interventions.

Mahshid Deldar Abad Paskeh, Ava Asadi, Sepideh Mirzaei, Mehrdad Hashemi, Maliheh Entezari, Rasoul Raesi, Kiavash Hushmandi, Ali Zarrabi, Yavuz Nuri Ertas, Amir Reza Aref, Saeed Samarghandian, Russel J Reiter, Jun Ren.

  Ischemia is a pathological process in which blood supply to a particular organ is temporarily interrupted resulting in disturbed biological function and homeostasis of local tissues. Following ischemia, reperfusion and reoxygenation may occur which further worsens oxidative stress-mediated damage in cells and tissues. The combined processes are referred to as ischemia/reperfusion (I/R) injury. Immediate management and treatment of I/R is of utmost importance for preventing irreversible and extensive cellular damage. Apoptosis, inflammation and oxidative stress are the most validated pathologies associated with I/R. AMP-activated protein kinase (AMPK) modulates energy metabolism in cells and its activation occurs in response to elevated AMP and ADP levels. Aberrant levels of AMPK are noted in various pathological settings such as diabetes mellitus, cancer and neurological diseases. This review emphasizes AMPK signaling, its related molecular pathways and therapeutic utility during I/R. Activation of AMPK through phosphorylation prevents apoptosis and reduces oxidative stress and inflammation upon I/R. Inducing AMPK signaling normalizes mitochondrial function to inhibit cell death. Autophagy as a cytoprotective mechanism undergoes activation by AMPK/mTOR and AMPK/ULK1 pathways. AMPK reinforces the antioxidant defense capacity via Nrf2 signaling to counteract oxidative stress in I/R. Protective compounds including phytochemicals activate AMPK to alleviate I/R injury.

Keywords:  AMPK; Apoptosis; Autophagy; Cell death; Ischemia/reperfusion injury; Oxidative stress

DOI:  https://doi.org/10.1016/j.cellsig.2022.110323
Hum Exp Toxicol. 2022 Jan-Dec;41:41 9603271211069984

Solasonine relieves sevoflurane-induced neurotoxicity via activating the AMP-activated protein kinase/FoxO3a pathway.

Huifang Zhang, Lei Yan.

  BACKGROUND: Solasonine (SS), the main active ingredient of Solanumnigrum L, has been reported to boast extensive anti-tumor, anti-oxidant, and anti-inflammatory properties. This study is committed to exploring whether solasonine can alleviate neurotoxicity resulting from sevoflurane.MATERIALS AND METHODS: The mouse hippocampal neuron cell line HT22 was treated with sevoflurane and/or solasonine of different doses. The proliferation, inflammation, oxidative stress response, and apoptosis of HT22 cells were examined. The AMP-activated protein kinase (AMPK)/FoxO3a signaling pathway was ascertained through Western blot and cellular immunofluorescence. In in-vivo experiments, Morris water maze figured out the changes in learning and memory abilities of mice treated with 8 mg/kg solasonine and exposed to SEV.
RESULTS: Sevoflurane induced apoptosis and hampered proliferation in HT22 cells. It also aggravated the release of inflammatory factors and oxidative stress mediators. Solasonine weakened neuron damage mediated by sevoflurane in a concentration-dependent pattern. Mechanically, sevoflurane clogged AMPK/FoxO3a signaling pathway activation, which was strengthened by solasonine. AMPK inhibition greatly influenced solasonine's protective effect on HT22 cells. Invivo, solasonine prominently ameliorated learning and memory disorders and nerve damage in mice exposed to sevoflurane.
CONCLUSIONS: Solasonine alleviates sevoflurane-induced neurotoxicity through activating the AMPK/FoxO3a signaling pathway.

Keywords:  AMP-activated protein kinase; FoxO3a pathway; apoptosis; neurotoxicity; sevoflurane; solasonine

DOI:  https://doi.org/10.1177/09603271211069984
Front Cardiovasc Med. 2022 ;9 840337

Atrial Lesions in a Pedigree With PRKAG2 Cardiomyopathy: Involvement of Disrupted AMP-Activated Protein Kinase Signaling.

Shaojie Chen, Yongping Lin, Yue Zhu, Le Geng, Chang Cui, Zhaomin Li, Hailei Liu, Hongwu Chen, Weizhu Ju, Minglong Chen.

  PRKAG2 cardiomyopathy is a rare progressive disease characterized by increased ventricular wall thickness and preexcitation. Dysfunction of the protein 5'-AMP-activated protein kinase (AMPK) plays a decisive role in the progression of ventricular lesions. Although patients with the PRKAG2-R302Q mutation have a high incidence of atrial fibrillation (AF), the molecular mechanism contributing to the disease remains unclear. We carried out whole-genome sequencing with linkage analysis in three affected members of a family. Atrial samples were obtained from the proband via surgical intervention. Control atrium biopsies were obtained from patients with persistent AF. Pathological changes were analyzed using the hematoxylin and eosin (H&E), Masson, and periodic acid-Schiff (PAS) staining. The AMPK signaling pathway was investigated by western blot. A murine atrial cardiomyocyte cell line (HL-1) and human induced pluripotent stem derived atrial cardiomyocytes (hiPSC-ACMs) were transfected with an adenovirus carrying the same mutation. We used enzyme linked immunosorbent assay (ELISA) to determine the AMPK activity in HL-1 cells and hiPSC-ACMs overexpressing PRKAG2-R302Q. Pathological results showed a large quantity of glycogen accumulation and vacuolization in cardiomyocytes from the proband atrial tissue. Western blot analysis revealed that the AMPK activity was significantly downregulated compared with that of the controls. Furthermore, remarkable glycogen deposition and impairment of AMPK activity were reproduced in HL-1 cells overexpressing PRKAG2-R302Q. Taken together, PRKAG2-R302Q mutation directly impair atrial cardiomyocytes. PRKAG2-R302Q mutation lead to glycogen deposition and promote the growth of atrial lesions by disrupting the AMPK pathway.

Keywords:  PRKAG2; atrial arrhythmia; glycogen deposition; histology; pedigree

DOI:  https://doi.org/10.3389/fcvm.2022.840337
Exp Neurol. 2022 Mar 24. pii: S0014-4886(22)00080-2. [Epub ahead of print] 114055

Metformin attenuates early brain injury after subarachnoid hemorrhage in rats via AMPK-dependent mitophagy.

Yongzhi Zhang, Tongyu Zhang, Yuchen Li, Yu Guo, Binbing Liu, Yang Tian, Pei Wu, Huaizhang Shi.

  Metformin is the most widely used drug to treat type 2 diabetes and its mitochondrial activity is through activation of adenosine monophosphate-activated protein kinase (AMPK). AMPK plays a dual regulatory role in mito-morphosis, controlling the phosphorylation and activation of dynamin-related protein 1 (DRP1) and mitofusin 2 (MFN2). The aim of this study was to investigate whether metformin could reduce early brain injury (EBI) after subarachnoid hemorrhage (SAH) by activating mitophagy and improving mitochondrial morphology through AMPK. This study used 308 male Sprague-Dawley rats. First, different metformin doses were injected intraperitoneally 30 min post-SAH. The dose that did not significantly alter blood glucose in the rats was selected for subsequent experiments. Before or after sacrificing rats, neurological function, brain water content, and blood-brain barrier (BBB) permeability were measured in each group. Transmission electron microscopy was used to observe the level of mitophagy and mito-morphology in each group. The expression of mitophagic and apoptotic proteins were investigated by immunofluorescence and western blot. Metformin at 20 mg/kg improved neurological function and attenuated brain edema and the disruption of BBB permeability 24 h after SAH. Metformin treatment after SAH promoted mitophagy in an AMPK-dependent manner. In addition to the effects on mitophagy, we also found that metformin alleviated oxidative stress and apoptosis after SAH in an AMPK-dependent manner. Lastly, metformin restored homeostasis between mitochondrial fusion and fission. Metformin attenuated EBI after SAH in rats through AMPK-dependent signaling. These protective effects might be achieved by regulating mitochondrial morphology and promoting mitophagy.

Keywords:  Early brain injury; Metformin; Mitophagy; Subarachnoid hemorrhage

DOI:  https://doi.org/10.1016/j.expneurol.2022.114055
Dis Markers. 2022 ;2022 8583674

ETC-1002 Attenuates Porphyromonas gingivalis Lipopolysaccharide-Induced Inflammation in RAW264.7 Cells via the AMPK/NF-κB Pathway and Exerts Ameliorative Effects in Experimental Periodontitis in Mice.

Hongyan Li, Peipei Zhang, Hongbing Lin, Huan Gao, Jianyuan Yin.

Background: Clinically, the failure of periodontal therapy stems largely from an inability to control the inflammatory response. Resolution of inflammation is an active, energy-requiring repair process, not merely a passive termination of inflammation. AMP-activated protein kinase (AMPK), a key energy sensor, has been shown to negatively regulate inflammatory signaling pathways. Thus, there is a crucial need for new therapeutic strategies to modulate AMPK and to promote enhanced resolution of inflammation. This study is aimed at investigating the anti-inflammatory effects of ETC-1002 through modulating AMPK in periodontitis.Methods: RAW264.7 cells were infected with Pg-LPS in the presence or absence of ETC-1002, following which the expression levels of proinflammatory cytokines and inflammation signaling-related proteins were evaluated by real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. ETC-1002 was applied in a murine model of periodontitis to determine its anti-inflammatory effect in vivo. Histological changes were investigated by hematoxylin and eosin (H&E) staining, the levels of proinflammatory cytokines were detected using immunohistochemistry, and alveolar bone height was measured using micro-CT imaging.
Results: ETC-1002 inhibited the production of proinflammatory cytokines, promoted AMPK phosphorylation, and decreased IκBα and NF-κB p65 phosphorylation levels in Pg-LPS-treated RAW264.7 macrophages. The inhibitory effects of ETC-1002 on the production of proinflammatory mediators were significantly abrogated by siRNA-mediated silencing of AMPKα in RAW264.7 cells. In vivo, ETC-1002 inhibited inflammatory cell infiltration, the expression of proinflammatory cytokines, and the inflammation-mediated destruction of alveolar bone in mice with experimental periodontitis. The anti-inflammatory effect of ETC-1002 in the periodontium could be reversed by the administration of Compound C, an AMPK inhibitor.
Conclusions: ETC-1002 exerts anti-inflammatory effects in Pg-LPS-treated RAW264.7 cells via the AMPK/NF-κB pathway in vitro and inhibits the progress of experimental periodontitis in mice in an AMPK signaling-dependent manner in vivo. These results provide evidence for the beneficial effects of ETC-1002 in the treatment of periodontitis.

DOI: https://doi.org/10.1155/2022/8583674
Biomed Pharmacother. 2022 Mar 25. pii: S0753-3322(22)00226-8. [Epub ahead of print]149 112838

Antidiabetic efficacy of Trifolium alexandrinum extracts hesperetin and quercetin in ameliorating carbohydrate metabolism and activating IR and AMPK signaling in the pancreatic tissues of diabetic rats.

Heba M Abdou, Fatma A Hamaad, Esraa Y Ali, Mamdooh H Ghoneum.

  Diabetes is a metabolic disease that is mainly characterized by hyperglycemia. The present work investigated the efficacy of the flavanones hesperetin (HES) and quercetin (Q) extracted from Trifolium alexandrinum (TA) to treat type 2 diabetic rats. Wistar albino rats were supplemented with a high fat diet (HFD) for 2 weeks and then administered streptozotocin to induce diabetes. Diabetic rats were orally treated with Q, HES, and TA extract at concentrations of 40, 50, and 200 mg/kg BW, respectively, for 4 weeks. Various biochemical, molecular, and histological analysis were performed to evaluate the antidiabetic effects of these treatments. Q, HES, and TA extract treatments all significantly improved diabetic rats' levels of serum glucose, insulin, glucagon, liver function enzymes, hepatic glycogen, α-amylase, lipase enzymes, lipid profiles, oxidative stress indicators, and antioxidant enzymes as compared with control diabetic untreated rats. In addition, supplementation with Q, HES, and TA extract attenuated the activities of glucose-6-phosphate; fructose-1,6-bisphospahate; 6-phosphogluconate dehydrogenase; glucose-6-phosphate dehydrogenase; glucokinase; and hexokinase in pancreatic tissue, and they improved the levels of glucose transporter 2 and glucose transporter 4. Furthermore, these treatments modulated the expressions levels of insulin receptor (IR), phosphoinositide 3-kinase (PI3K), AMP-activated protein kinase (AMPK), caspase-3, and interleukin-1β (IL-1β). Enhancement of the histological alterations in pancreatic tissues provided further evidence of the ability of Q, HES, and TA extract to exert antidiabetic effects. Q, HES, and TA extract remedied insulin resistance by altering the IR/PI3K and AMPK signaling pathways, and they attenuated type 2 diabetes by improving the antioxidant defense system.

Keywords:  AMPK; Glucose metabolism; Hesperetin; High fat diet; IR; Quercetin; Trifolium alexandrinum (TA) extract

DOI:  https://doi.org/10.1016/j.biopha.2022.112838
Oxid Med Cell Longev. 2022 ;2022 3589277

The Activation of AMPK/NRF2 Pathway in Lung Epithelial Cells Is Involved in the Protective Effects of Kinsenoside on Lipopolysaccharide-Induced Acute Lung Injury.

Yue Yang, Zhen-Tong Zhong, Yong-Guang Xiao, Hong-Bin Chen.

The disorder of mitochondrial dynamic equilibrium of lung epithelial cell is one of the critical causes of acute lung injury (ALI). Kinsenoside (Kin) serves as an active small-molecule component derived from traditional medicinal herb displaying multiple pharmacological actions in cancers, hyperglycemia, and liver disease. The objective of this study was to investigate the effects of Kin on lipopolysaccharide- (LPS-) induced ALI and further explore possible molecular mechanisms. Kin was administered orally (100 mg/kg/day) for 7 consecutive days before LPS instillation (5 mg/kg). After 12 hours, pathological injury, inflammatory response, and oxidative stress were detected. The results demonstrated that Kin significantly alleviated lung pathological injury and decreased the infiltration of inflammatory cells and the release of inflammatory mediators in bronchoalveolar lavage fluid (BALF), apart from inhibiting the production of reactive oxygen species (ROS) and lipid peroxidation. Meanwhile, Kin also promoted mitochondrial fusion and restrained mitochondrial fission in mice with ALI. In terms of mechanism, Kin pretreatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and the protein level of nuclear factor erythroid 2-related factor 2 (NRF2). In Ampk-α knockout mice challenged with LPS, Kin lost its pulmonary protective effects, accompanied by lower NRF2 level. In vitro experiments further unveiled that either AMPK inhibition by Compound C or NRF2 knockdown by siRNA abolished the protective roles of Kin in LPS-treated A549 lung epithelial cells. And NRF2 activator TAT-14 could reverse the effects of Ampk-α deficiency. In conclusion, Kin possesses the ability to prevent LPS-induced ALI by modulating mitochondrial dynamic equilibrium in lung epithelial cell in an AMPK/NRF2-dependent manner.

DOI: https://doi.org/10.1155/2022/3589277
Clin Transl Med. 2022 Mar;12(3): e777

MD2 deficiency prevents high-fat diet-induced AMPK suppression and lipid accumulation through regulating TBK1 in non-alcoholic fatty liver disease.

Wu Luo, Lin Ye, Xue-Ting Hu, Mei-Hong Wang, Min-Xiu Wang, Lei-Ming Jin, Zhong-Xiang Xiao, Jian-Chang Qian, Yi Wang, Wei Zuo, Li-Jiang Huang, Guang Liang.

  BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most predominant form of liver diseases worldwide. Recent evidence shows that myeloid differentiation factor 2 (MD2), a protein in innate immunity and inflammation, regulates liver injury in models of NAFLD. Here, we investigated a new mechanism by which MD2 participates in the pathogenesis of experimental NAFLD.METHODS: Wild-type, Md2-/- and bone marrow reconstitution mice fed with high-fat diet (HFD) were used to identify the role of hepatocyte MD2 in NAFLD. Transcriptomic RNA-seq and pathway enrich analysis were performed to explore the potential mechanisms of MD2. In vitro, primary hepatocytes and macrophages were cultured for mechanistic studies.
RESULTS: Transcriptome analysis and bone marrow reconstitution studies showed that hepatocyte MD2 may participate in regulating lipid metabolism in models with NAFLD. We then discovered that Md2 deficiency in mice prevents HFD-mediated suppression of AMP-activated protein kinase (AMPK). This preservation of AMPK in Md2-deficient mice was associated with normalized sterol regulatory element binding protein 1 (SREBP1) transcriptional program and a lack of lipid accumulation in both hepatocytes and liver. We then showed that hepatocyte MD2 links HFD to AMPK/SREBP1 through TANK binding kinase 1 (TBK1). In addition, MD2-increased inflammatory factor from macrophages induces hepatic TBK1 activation and AMPK suppression.
CONCLUSION: Hepatocyte MD2 plays a pathogenic role in NAFLD through TBK1-AMPK/SREBP1 and lipid metabolism pathway. These studies provide new insight into a non-inflammatory function of MD2 and evidence for the important role of MD2 in NALFD.

Keywords:  AMPK/SREBP1; MD2; NAFLD; TBK1; lipid accumulation

DOI:  https://doi.org/10.1002/ctm2.777
Obesity (Silver Spring). 2022 Mar 31.

Hepatocyte-specific eNOS deletion impairs exercise-induced adaptations in hepatic mitochondrial function and autophagy.

Rory P Cunningham, Mary P Moore, Ryan J Dashek, Grace M Meers, Vivien Jepkemoi, Takamune Takahashi, Victoria J Vieira-Potter, Jill A Kanaley, Frank W Booth, R Scott Rector.

OBJECTIVE: Endothelial nitric oxide synthase (eNOS) is a potential mediator of exercise-induced hepatic mitochondrial adaptations.METHODS: Here, male and female hepatocyte-specific eNOS knockout (eNOShep-/- ) and intact hepatic eNOS (eNOSfl/fl ) mice performed voluntary wheel-running exercise (EX) or remained in sedentary cage conditions for 10 weeks.
RESULTS: EX resolved the exacerbated hepatic steatosis in eNOShep-/- male mice. Elevated hydrogen peroxide emission (~50% higher in eNOShep-/- vs. eNOSfl/fl mice) was completely ablated with EX. Interestingly, EX increased [1-14 C] palmitate oxidation in eNOSfl/fl male mice, but this was blunted in the eNOShep-/- male mice. eNOShep-/- mice had lower markers of the energy sensors AMP-activated protein kinase (AMPK)/phospho- (p)AMPK and mammalian target of rapamycin (mTOR) and p-mTOR, as well as the autophagy initiators serine/threonine-protein kinase ULK1 and pULK1, compared with eNOSfl/fl mice. Females showed elevated electron transport chain protein content and markers of mitochondrial biogenesis (transcription factor A, mitochondrial, peroxisome proliferator-activated receptor-gamma coactivator 1α).
CONCLUSIONS: Collectively, this study demonstrates for the first time, to the authors' knowledge, the requirement of eNOS in hepatocytes in the EX-induced increases in hepatic fatty acid oxidation in male mice. Deletion of eNOS in hepatocytes also appears to impair the energy-sensing ability of the cell and inhibit the activation of the autophagy initiating factor ULK1. These data uncover the important and novel role of hepatocyte eNOS in EX-induced hepatic mitochondrial adaptations.

DOI: https://doi.org/10.1002/oby.23414
Acta Pharmacol Sin. 2022 Mar 30.

IMM-H007 attenuates isoprenaline-induced cardiac fibrosis through targeting TGFβ1 signaling pathway.

Shuai-Xing Wang, Ye-Nan Feng, Shan Feng, Ji-Min Wu, Mi Zhang, Wen-Li Xu, You-Yi Zhang, Hai-Bo Zhu, Han Xiao, Er-Dan Dong.

  Upon chronic stress, β-adrenergic receptor activation induces cardiac fibrosis and leads to heart failure. The small molecule compound IMM-H007 has demonstrated protective effects in cardiovascular diseases via activation of AMP-activated protein kinase (AMPK). This study aimed to investigate IMM-H007 effects on cardiac fibrosis induced by β-adrenergic receptor activation. Because adenosine analogs also exert AMPK-independent effects, we assessed AMPK-dependent and -independent IMM-H007 effects in murine models of cardiac fibrosis. Continual subcutaneous injection of isoprenaline for 7 days caused cardiac fibrosis and cardiac dysfunction in mice in vivo. IMM-H007 attenuated isoprenaline-induced cardiac fibrosis, diastolic dysfunction, α-smooth muscle actin expression, and collagen I deposition in both wild-type and AMPKα2-/- mice. Moreover, IMM-H007 inhibited transforming growth factor β1 (TGFβ1) expression in wild-type, but not AMPKα2-/- mice. By contrast, IMM-H007 inhibited Smad2/3 signaling downstream of TGFβ1 in both wild-type and AMPKα2-/- mice. Surface plasmon resonance and molecular docking experiments showed that IMM-H007 directly interacts with TGFβ1, inhibits its binding to TGFβ type II receptors, and downregulates the Smad2/3 signaling pathway downstream of TGFβ1. These findings suggest that IMM-H007 inhibits isoprenaline-induced cardiac fibrosis via both AMPKα2-dependent and -independent mechanisms. IMM-H007 may be useful as a novel TGFβ1 antagonist.

Keywords:  AMP-activated protein kinase; IMM-H007; cardiac fibrosis; sympathetic stress; transforming growth factor β1

DOI:  https://doi.org/10.1038/s41401-022-00899-2
Front Physiol. 2022 ;13 837798

Sleeve Gastrectomy-Induced AMPK Activation Attenuates Diabetic Cardiomyopathy by Maintaining Mitochondrial Homeostasis via NR4A1 Suppression in Rats.

Songhan Li, Shuohui Dong, Qian Xu, Bowen Shi, Linchuan Li, Wenjie Zhang, Jiankang Zhu, Yugang Cheng, Guangyong Zhang, Mingwei Zhong.

  Diabetic cardiomyopathy (DCM) is characterized by impaired diastolic and systolic myocardial performance and is a major cause of morbidity and mortality in patients with diabetes. Surgical bariatric procedures, such as sleeve gastrectomy (SG), result in remission of type 2 diabetes (T2DM) and have benefits with myocardial function. Maintaining cardiac mitochondrial homeostasis is a promising therapeutic strategy for DCM. However, whether SG surgery affects mitochondrial function and its underlying mechanism remains unclear. This study aimed to investigate the effect of SG surgery on mitochondrial homeostasis and intracellular oxidative stress in rats with DCM. We also examined cellular phenotypes and molecular mechanisms in high glucose and high fat-stimulated myocytes. The rat model of DCM was established by high-fat diet feeding and low-dose streptozotocin injection. We observed a remarkably metabolic benefit of SG, including a reduced body weight, food intake, blood glucose levels, and restored glucose tolerance and insulin sensitivity post-operatively. Also, SG ameliorated the pathological cardiac hypertrophy, myocardial fibrosis and the dysfunction of myocardial contraction and diastole, consequently delayed the progression of DCM. Also, SG restored the mitochondrial dysfunction and fragmentation through the AMPK signaling activation mediated nuclear receptor subfamily 4 group A member 1 (NR4A1)/DRP1 suppression in vivo. H9c2 cardiomyocytes showed that activation of AMPK could reverse the mitochondrial dysfunction somehow. Collectively, our study provided evidence that SG surgery could alleviate mitochondrial dysfunction in DCM. Moreover, AMPK-activated NR4A1/DRP1 repression might act as a significant reason for maintaining mitochondrial homeostasis in the myocardium, thus contributing to morphological and functional alleviation of DCM.

Keywords:  AMPK; NR4A1; diabetic cardiomyopathy; mitochondrial homeostasis; oxidative stress; sleeve gastrectomy

DOI:  https://doi.org/10.3389/fphys.2022.837798
Am J Physiol Endocrinol Metab. 2022 Mar 28.

Fasting potentiates insulin-mediated glucose uptake in rested and prior-contracted rat skeletal muscle.

Kohei Kido, Tatsuro Egawa, Shinya Watanabe, Kentaro Kawanaka, Jonas T Treebak, Tatsuya Hayashi.

  A single bout of exercise can potentiate the effect of insulin on skeletal muscle glucose uptake via activation of the AMPK-TBC1D4 pathway, which suggests a positive correlation between AMPK activation and insulin sensitization. Additionally, prolonged fasting in rodents is known to upregulate and thereby synergistically enhance the effect of exercise on muscle AMPK activation. Therefore, fasting may potentiate the insulin-sensitizing effect of exercise. In the present study, we mimicked exercise by in situ muscle contraction and evaluated the effect of a 36 h fast on muscle contraction-induced insulin sensitization. Male Wistar rats weighing 150-170 g were allocated to either a 36-h fasting or feeding group. The extensor digitorum longus (EDL) muscles were electrically contracted via the common peroneal nerve for 10 min followed by a 3 h recovery period. EDL muscles were dissected and incubated in the presence or absence of submaximal insulin. Our results demonstrated that acute muscle contraction and 36 h of fasting additively upregulated AMPK pathway activation. Insulin-stimulated muscle glucose uptake and site-specific TBC1D4 phosphorylation were enhanced by prior muscle contraction in 36-h fasted rats, but not in fed rats. Moreover, enhanced insulin-induced muscle glucose uptake and Akt phosphorylation due to 36 h of fasting was associated with a decrease in tribbles homolog 3 (TRB3), a negative regulator of Akt activation. In conclusion, fasting and prior muscle contraction synergistically enhance insulin-stimulated TBC1D4 phosphorylation and glucose uptake, which is associated with augmented AMPK pathway activation in rodents.

Keywords:  AMPK; fasting; glucose uptake; insulin sensitivity; skeletal muscle

DOI:  https://doi.org/10.1152/ajpendo.00412.2021
Exp Cell Res. 2022 Mar 24. pii: S0014-4827(22)00113-6. [Epub ahead of print]415(1): 113120

Metformin alleviates dexamethasone-induced apoptosis by regulating autophagy via AMPK/mTOR/p70S6K in osteoblasts.

Xintong Guo, Min Liang.

  Glucocorticoid (GC)-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Osteoblast apoptosis induced by GCs is now considered as a crucial factor for GIOP. Many clinical, in vivo, and in vitro studies have shown that metformin has a beneficial effect on bone metabolism and bone formation. To investigate whether metformin could be used to treat GIOP, we explored the influence of metformin on dexamethasone (Dex)-induced apoptosis of osteoblasts and its underlying mechanisms. In this study, the CCK8 assay was used to determine the optimal metformin concentration and processing time. The expression levels of target proteins were examined by Western blot and immunofluorescence; the expression levels of target genes were tested by quantitative PCR. Apoptotic cells were detected using flow cytometry. Characteristics of autophagy were observed by transmission electron microscopy. An autophagy inhibitor was administered to investigate whether autophagy decreases apoptosis. Sh-AMPK transfection and an mTOR activator were used to investigate the role of AMPK/mTOR signaling in metformin-induced autophagy. The results showed that metformin alleviated Dex-induced apoptosis of osteoblasts accompanied by increased autophagy. Treatment with the autophagy inhibitor 3-methyladenine (3-MA) attenuated the effect of metformin on apoptosis, autophagy, and the AMPK/mTOR/p70S6K signaling pathway. The anti-apoptotic effect of metformin on osteoblasts is associated with the promotion of autophagy. Furthermore, sh-AMPK transfection and the mTOR activator MHY1485 impaired metformin-mediated inhibition of osteoblast apoptosis and promotion of autophagy. The AMPK/mTOR/p70S6K signaling pathway plays a role in metformin-mediated apoptosis suppression and autophagy promotion. In conclusion, metformin can alleviate Dex-induced osteoblast apoptosis by inducing autophagy via the AMPK/mTOR/p70S6K pathway. This study highlights the potential value of metformin in the treatment of GIOP.

Keywords:  Apoptosis; Autophagy; Dexamethasone; Metformin; Osteoblasts; Osteoporosis

DOI:  https://doi.org/10.1016/j.yexcr.2022.113120
Food Funct. 2022 Mar 31.

Lipid metabolism disorders and lipid mediator changes of mice in response to long-term exposure to high-fat and high sucrose diets and ameliorative effects of mulberry leaves.

Yan Du, Ding-Xiang Li, Dong-Yu Lu, Ran Zhang, Yan-Lin Zhao, Qiao-Qiao Zhong, Shuai Ji, Liang Wang, Dao-Quan Tang.

Mulberry leaves exhibit anti-lipogenic and lipid-lowering effects. However, the lipid biomarkers and underlying mechanisms for the improvement of the action of mulberry leaves on obesity and lipid metabolism disorders have not been sufficiently investigated yet. Herein, biochemical analysis combined with metabolomics targeting serum lipid mediators (oxylipins) were used to explore the efficacy and underlying mechanisms of mulberry leaf water extract (MLWE) in high-fat and high-sucrose diet (HFHSD)-fed mice. Our results showed that MLWE supplementation not only decreased body weight gain, serum total triglycerides, low-density lipoprotein cholesterol, alanine transaminase and aspartate transaminase levels, but also increased the serum level of high-density lipoprotein cholesterol. In addition, MLWE supplementation also ameliorated hepatic steatosis and lipid accumulation. These beneficial effects were associated with down-regulating genes involved in oxidative stress, inflammation, and lipogenesis such as acetyl-CoA carboxylase and fatty acid synthase, and up-regulating genes related to lipolysis that encoded peroxisome proliferator-activated receptor α, adiponectin (ADPN), adiponectin receptor (AdipoR) 1, AdipoR2, adenosine monophosphate-activated protein kinase (AMPK) and hormone-sensitive lipase. Moreover, a total of 54 serum lipid mediators were differentially changed in HFHSD-fed mice, among which 11 lipid mediators from n-3 polyunsaturated fatty acids (PUFAs) were apparently reversed by MLWE. These findings indicated that the ADPN/AMPK pathway, anti-inflammation, anti-oxidation, and n-3 PUFA metabolism played important roles in anti-obesity and improvement of lipid metabolism disorders modulated by MLWE supplementation.

DOI: https://doi.org/10.1039/d1fo04146k
J Pain. 2022 Mar 23. pii: S1526-5900(22)00048-7. [Epub ahead of print]

Activation of 20-HETE Synthase Triggers Oxidative Injury and Peripheral Nerve Damage in Type 2 Diabetic Mice.

Mary Haddad, Stéphanie Eid, Frederic Harb, Mohamed El Massry, Sami Azar, Erik-Andre Sauleau, Assaad Eid.

  Diabetic Peripheral Neuropathy (DPN), highly prevalent among patients with diabetes, is characterized by peripheral nerve dysfunction. Reactive Oxygen Species (ROS) overproduction has been suggested to orchestrate diabetic complications including DPN. Untargeted antioxidant therapy has exhibited limited efficacy, highlighting a critical need to explore ROS sources altered in a cell-specific manner in DPN. Cytochromes P450 (CYP) enzymes are prominent sources of ROS. Particularly, the 20-HETE synthase, CYP4A, is reported to mediate diabetes-induced renal, retinal, and cardiovascular injuries. This work investigates the role of CYP4A/20-HETE in DPN and their mechanisms of action. Non-obese type 2 Diabetic mice (MKR) were used and treated with a CYP4A-inhibitor (HET0016) or AMPK-activator (Metformin). Peripheral nerves of MKR mice reflect increased CYP4A and 20-HETE levels, concurrent with altered myelin proteins and sensorimotor deficits. This was associated with increased ROS production and altered Beclin-1 and LC3 protein levels, indicative of disrupted autophagic responses in tandem with AMPK inactivation. AMPK activation via Metformin restored nerve integrity, reduced ROS production, and regulated autophagy. Interestingly, similar outcomes were revealed upon HET0016 treatment whereby ROS production, autophagic responses, and AMPK signaling were normalized in diabetic mice. Altogether, the results highlight hyperglycemia-mediated oxidative injury in DPN through a novel CYP4A/20-HETE/AMPK pathological axis. Perspective: To our knowledge, this is the first study to highlights the role of CYPs/20-HETE-induced oxidative injury in the pathogenesis of diabetic peripheral neuropathy. Targeting the identified pathological axis CYP4A/20-HETE/AMPK may be of clinical potential in predicting and alleviating peripheral nerve injury in patients with Type 2 Diabetes Mellitus.

Keywords:  20-HETE; AMPK; Diabetic Peripheral Neuropathy; Insulin resistance; Oxidative Stress

DOI:  https://doi.org/10.1016/j.jpain.2022.02.011
Biochem Pharmacol. 2022 Mar 28. pii: S0006-2952(22)00116-2. [Epub ahead of print] 115022

Valdecoxib attenuates lipid-induced hepatic steatosis through autophagy-mediated suppression of endoplasmic reticulum stress.

Seung Yeon Park, Wonjun Cho, A M Abd El-Aty, Ahmet Hacimuftuoglu, Ji Hoon Jeong, Tae Woo Jung.

  Valdecoxib (VAL) is one of the non-steroidal anti-inflammatory drugs (NSAIDs) used to treat inflammatory disorders, such as rheumatoid arthritis, osteoarthritis, and menstrual cramps. Recently, VAL ameliorates skeletal muscle insulin resistance via suppression of inflammation. However, the effects of VAL on lipid metabolism in hepatocytes have not been seen yet. This study investigated the effects of VAL on lipid accumulation and lipogenesis in human primary hepatocytes. Treatment with VAL suppressed lipid accumulation and expressions of lipogenic genes, such as processed sterol regulatory element binding proteins (SREBP1) and stearoyl-CoA desaturase-1 (SCD1) in palmitate-treated hepatocytes. Furthermore, VAL ameliorated dose-dependently palmitate-induced ER stress markers. Treatment of hepatocytes with VAL increased AMPK phosphorylation and SIRT6 expression. siRNA-mediated suppression of AMPK or SIRT6 abolished the effects of VAL on lipid accumulation, lipogenesis, and endoplasmic reticulum (ER) stress in palmitate-treated hepatocytes. Administration of VAL ameliorated hepatic lipid accumulation and lipogenic protein expression in HFD-fed mice. Moreover, in vivo AMPK siRNA transfection abolished the effects of VAL on hepatic steatosis and lipid metabolism. These results suggest that VAL suppresses ER stress through the AMPK/SIRT6 pathway, thereby attenuating hepatic steatosis under hyperlipidemic conditions. Using VAL, the current study results provide clues for developing a novel therapeutic agent for treating non-alcoholic fatty liver disease.

Keywords:  AMPK; Autophagy; ER stress; NAFLD; SIRT6; Valdecoxib

DOI:  https://doi.org/10.1016/j.bcp.2022.115022
J Integr Neurosci. 2022 Mar 18. 21(2): 46

A review of autophagy mechanism of statins in the potential therapy of Alzheimer's disease.

Lu Liu, Wen-Zhuo Dai, Xi-Chen Zhu, Tao Ma.

  Alzheimer's disease (AD) is a neurodegeneration csharacterized by amyloid-β (Aβ) deposition and abnormally phosphorylated Tau protein aggregation. Autophagy, as an important cellular metabolic activity, is closely related to the production, secretion and clearance of Aβ peptide and Tau phosphorylation level. Therefore, autophagy may become a potential target for AD treatment. A large number of molecules are involved in the mammalian target of rapamycin (mTOR)-dependent or mTOR-independent pathway of autophagy. More and more evidences show that statins can intervene autophagy by regulating the activity or expression level of autophagy-related proteins and genes. On the one hand, statins can induce autophagy through Sirtuin1 (SIRT1), P21, nuclear P53 and adenylate activated protein kinase (AMPK). On the other hand, statins inhibit the mevalonate metabolism pathway, thereby interfering with the prenylation of small GTPases, leading to autophagy dysfunction. Statins can also reduce the levels of LAMP2 and dynein, destroying autophagy. In this review, we focused on the role of autophagy in AD and the autophagy mechanism of statins in the potential treatment of AD.

Keywords:  Alzheimer's disease; Amyloid-β; Autophagy; Autophagy flux; Mevalonate pathway; Statin; Tau protein

DOI:  https://doi.org/10.31083/j.jin2102046
Aging (Albany NY). 2022 Mar 28. 14(undefined):

Effects of caloric overload before caloric restriction in the murine heart.

Martin Maldonado, Jianying Chen, Huiqin Duan, Shuling Zhou, Lujun Yang, Mazhar Ali Raja, Tianhua Huang, Gu Jiang, Ying Zhong.

  The beneficial effects of caloric restriction (CR) against cardiac aging and for prevention of cardiovascular diseases are numerous. However, to our knowledge, there is no scientific evidence about how a high-calorie diet (HCD) background influences the mechanisms underlying CR in whole heart tissue (WHT) in experimental murine models. In the current study, CR-treated mice with different alimentary backgrounds were subjected to transthoracic echocardiographic measurements. WHT was then analyzed to determine cardiac energetics, telomerase activity, the expression of energy-sensing networks, tissue-specific adiponectin, and cardiac precursor/cardiac stem cell markers. Animals with a balanced diet consumption before CR presented marked cardiac remodeling with improved ejection fraction (EF) and fractional shortening (FS), enhanced OXPHOS complex I, III, and IV, and CKMT2 enzymatic activity. Mice fed an HCD before CR presented moderate changes in cardiac geometry with diminished EF and FS values, but improved OXPHOS complex IV and CKMT2 activity. Differences in cardiac remodeling, left ventricular systolic/diastolic performance, and mitochondrial energetics, found in the CR-treated mice with contrasting alimentary backgrounds, were corroborated by inconsistencies in the expression of mitochondrial-biogenesis-related markers and associated regulatory networks. In particular, disruption of eNOS and AMPK -PGC-1α-mTOR-related axes. The impact of a past habit of caloric overload on the effects of CR in the WHT is a scarcely explored subject that requires deeper study in combination with analyses of other tissues and organs at higher levels of organization within the organ system. Such research will eventually lead to the development of preventative and therapeutic strategies to promote health and longevity.

Keywords:  AMPK; PGC1-α; SIRT1; caloric restriction; cardiac function; mTOR; mitochondria; telomerase

DOI:  https://doi.org/10.18632/aging.203967
Int J Mol Med. 2022 May;pii: 71. [Epub ahead of print]49(5):

2,3,4',5‑Tetrahydroxystilbene‑2‑O‑β‑D‑glucoside ameliorates gentamicin‑induced ototoxicity by modulating autophagy via Sesn2/AMPK/mTOR signaling.

Yu-Hsuan Wen, Hui-Yi Lin, Jia-Ni Lin, Guo-Fang Tseng, Chung-Feng Hwang, Chung-Ching Lin, Chuan-Jen Hsu, Hung-Pin Wu.

  Gentamicin is an important aminoglycoside antibiotic used in the treatment of gram‑negative bacterial infections, but nephrotoxicity and ototoxicity reduce its utility. The autophagy pathway is involved in damage of auditory hair cells. With the aim of developing new strategies for attenuating gentamicin ototoxicity, the present study investigated the otoprotective mechanism of 2,3,4',5‑tetrahydroxystilbene‑2‑O‑β‑D-glucoside (THSG) in vitro using the mouse cochlear cell line UB/OC‑2. MTT assay demonstrated that gentamicin reduced UB/OC‑2 cell viability and western blotting showed that gentamicin upregulated autophagy‑related proteins, such as Beclin, autophagy related 5 and LC3‑II. THSG significantly attenuated gentamicin‑induced cytotoxicity, clearly reduced LDH release observed by LDH assay and decreased the expression of autophagy‑related proteins. Reverse‑transcription‑quantitative (RT‑q) PCR and western blotting showed that THSG against gentamicin‑induced autophagy via suppressing the expression of Sesn2, at both the mRNA and protein level and a possible involvement of AMP‑activated protein kinase (AMPK)/mTOR signaling response. Collectively, the present study demonstrated that THSG decreased gentamicin‑induced ototoxicity in UB/OC‑2 cochlear cells via the autophagic signaling in regulating Sesn2/AMPK/mTOR pathway. These results suggested that THSG might be a new therapeutic agent with the potential to attenuate gentamicin ototoxicity.

Keywords:  2; 3; 4'; 5‑tetrahydroxystilbene‑2-O‑β‑D‑glucoside; UB/OC‑2 cochlear cells; autophagy; gentamicin; ototoxicity

DOI:  https://doi.org/10.3892/ijmm.2022.5127
J Oncol. 2022 ;2022 3780854

Mechanism of N-Methyl-N-Nitroso-Urea-Induced Gastric Precancerous Lesions in Mice.

Sheng-Xiong Zhang, Wen Tian, Yuan-Liang Liu, Jia-Hui Ni, Dan Zhang, Hua-Feng Pan, Zi-Ming Zhao, Bo Ai, Zhe-Sheng Chen, Li-Zhu Lin, Wei Liu.

Early diagnosis and treatment of gastric precancerous lesions (GPL) are key factors for reducing the incidence and morbidity of gastric cancer. The study is aimed at examining GPL in mice induced by N-methyl-N-nitroso-urea (MNU) and to illustrate the underlying mechanisms of tumorigenesis. In this study, we utilized an in vivo MNU-induced GPL mouse model, and histopathological changes of the gastric mucosa were observed by hematoxylin and eosin (H&E-stain) and alcian blue (AB-PAS-stain). The level of miR-194-5p in the gastric mucosa was determined by real-time polymerase chain reaction. We used transmission electron microscopy to observe the effects of MNU on gastric chief cells and parietal cells. We performed immunohistochemical detection of HIF-1α, vWF, Ki-67, and P53, while the changes in the protein expression of key genes in LKB1-AMPK and AKT-FoxO3 signaling pathways were detected by western blot analysis. We demonstrated that the miR-194-5p expression was upregulated under hypoxia in GPL gastric tissues, and that a high miR-194-5p expression level closely related with tumorigenesis. Mechanistically, miR-194-5p exerted the acceleration of activities related to metabolic reprogramming through LKB1-AMPK and AKT-FoxO3 pathways. Furthermore, similar to miR-194-5p, high expression levels of AMPK and AKT were also related to the metabolic reprogramming of GPL. Moreover, we revealed the correlation between the expression levels of miR-194-5p, p-AMPKα, p-AKT, and FoxO3a. These findings suggest that miR-194-5p/FoxO3 pathway is important for the reversal of metabolic reprogramming in GPL. Thus, exploring strategies to regulate the miR-194-5p/FoxO3a pathway may provide an efficient strategy for the prevention and treatment of GPL.

DOI: https://doi.org/10.1155/2022/3780854
Ultrastruct Pathol. 2022 Mar 29. 1-8

The mitophagosome, a novel ultrastructure of mitophagy in the alcoholic steatohepatitis mouse model: a transmission electron microscope study.

Yanfei Lang, Xiaxia Zhang, Xin Li, Youqing Xu.

  Acute alcohol feeding can activate autophagy and promotes the selection of autophagic vacuoles in the mitochondria, which is a key process regulating the occurrence and progression of alcohol steatohepatitis (ASH). In this study, ASH mice expressed more autophagy-associated proteins than healthy controls, as revealed by immunohistochemistry. In addition, transmission electron microscopy (TEM) detected a unique autophagy ultrastructure in ASH mouse liver cells, consisting of a large vesicle fused directly with mitochondria, which differed from the classical pattern. This novel type of mitophagy may provide a new avenue for a protective mechanism targeting mitophagy, which would benefit patients with ASH.Abbreviations: ASH: alcoholic steatohepatitis; ALD: Alcoholic liver disease; ALT: alanine aminotransferase; AST: aspartate aminotransferase; HE: hematoxylin and eosin; TEM: transmission electron microscope; LC3: microtubule-associated protein 1 light chain 3; SQSTM1/p62: sequestosome 1; UQCRC2: ubiquinol-cytochrome c reductase core protein 2; PINK1: PTEN induced kinase 1; AMPK: AMP-activated protein kinase.

Keywords:  Alcoholic steatohepatitis; mitophagy; selective autophagy; transmission electron microscope

DOI:  https://doi.org/10.1080/01913123.2022.2059041
Inflammopharmacology. 2022 Apr 01.

Neuroprotective effect of liraglutide in an experimental mouse model of multiple sclerosis: role of AMPK/SIRT1 signaling and NLRP3 inflammasome.

Reham A Ammar, Ahmed F Mohamed, Mohamed M Kamal, Marwa M Safar, Noha F Abdelkader.

  The heterogeneous nature of multiple sclerosis (MS) and the unavailability of treatments addressing its intricate network and reversing the disease state is yet an area that needs to be elucidated. Liraglutide, a glucagon-like peptide-1 analogue, recently exhibited intriguing potential neuroprotective effects. The currents study investigated its potential effect against mouse model of MS and the possible underlying mechanisms. Demyelination was induced in C57Bl/6 mice by cuprizone (400 mg/kg/day p.o.) for 5 weeks. Animals received either liraglutide (25 nmol/kg/day i.p.) or dorsomorphin, an AMPK inhibitor, (2.5 mg/Kg i.p.) 30 min before the liraglutide dose, for 4 weeks (starting from the second week). Liraglutide improved the behavioral profile in cuprizone-treated mice. Furthermore, it induced the re-myelination process through stimulating oligodendrocyte progenitor cells differentiation via Olig2 transcription activation, reflected by increased myelin basic protein and myelinated nerve fiber percentage. Liraglutide elevated the protein content of p-AMPK and SIRT1, in addition to the autophagy proteins Beclin-1 and LC3B. Liraglutide halted cellular damage as manifested by reduced HMGB1 protein and consequently TLR-4 downregulation, coupled with a decrease in NF-κB. Liraglutide also suppressed NLRP3 transcription. Dorsomorphin pre-administration indicated a possible interplay between AMPK/SIRT1 and NLRP3 inflammasome activation as it partially reversed liraglutide's effects. Immunohistochemical examination of Iba+ microglia emphasized these findings. In conclusion, liraglutide exerts neuroprotection against cuprizone-induced demyelination via anti-inflammatory, autophagic flux activation, NLRP3 inflammasome suppression, and anti-apoptotic mechanisms, possibly mediated, at least in part, via AMPK/SIRT1, autophagy, TLR-4/ NF-κB/NLRP3 signaling. The potential mechanistic insight of Lira in alleviating Cup-induced neurotoxicity via: (1) AMPK/SIRT1 pathways activation resulting in the stimulation of brain autophagy flux (confirmed by lowering Beclin-1 and LC3-B protein expression). (2) Inhibition of NLRP3 inflammasome activation, as evidenced by reduced HMGB1, TLR-4, NF-κB and NLRP3 protein expression, alongside diminishing the activation of its downstream cascade as reflected by reduced levels of caspase-1 and IL-1β protein expression. (3) A possible modulating interplay between the previously mentioned two pathways.

Keywords:  AMPK/SIRT1; Autophagy; Dorsomorphin; Liraglutide; Multiple sclerosis; NLRP3 inflammasome

DOI:  https://doi.org/10.1007/s10787-022-00956-6
Exp Ther Med. 2022 Apr;23(4): 307

Mitochondrial dynamics and biogenesis indicators may serve as potential biomarkers for diagnosis of myasthenia gravis.

Lanqi Li, Donghong Cai, Huiya Zhong, Fengbin Liu, Qilong Jiang, Jian Liang, Peiwu Li, Yafang Song, Aidong Ji, Wei Jiao, Jingwei Song, Jinqiu Li, Zhiwei Chen, Qing Li, Lingling Ke.

  Due to challenges in diagnosing myasthenia gravis (MG), identifying novel diagnostic biomarkers for this disease is essential. Mitochondria are key organelles that regulate multiple physiological functions, such as energy production, cell proliferation and cell death. In the present study, Mfn1/2, Opa1, Drp1, Fis1, AMPK, PGC-1α, NRF-1 and TFAM were compared between patients with MG and healthy subjects to identify potential diagnostic biomarkers for MG. Blood samples were collected from 50 patients with MG and 50 healthy subjects. The participants' demographic information and routine blood test results were recorded. Mitochondrial dynamics were evaluated and levels of Mfn1/2, Opa1, Drp1, Fis1, AMPK, PGC-1α, NRF-1 and TFAM were determined in peripheral blood mononuclear cells using western blotting and reverse transcription-quantitative PCR, respectively. Receiver operating characteristic curve analysis was used to evaluate the diagnostic accuracy of these indicators. The areas under the curve values of Mfn1/2, Opa1, Drp1, Fis1,AMPK, PGC-1α, NRF-1 and TFAM were 0.5408-0.8696. Compared with control subjects, mRNA expression levels of Mfn1/2, Opa1, AMPK, PGC-1α, NRF-1 and TFAM were lower, while those of Drp1 and Fis1 were higher in patients with MG. The protein expression levels of all these molecules were lower in patients with MG than in control subjects. These results suggested that mitochondrial dynamics and biogenesis indicators may be diagnostic biomarkers for MG.

Keywords:  biogenesis; biomarkers; mitochondrial dynamics; myasthenia gravis; peripheral blood mononuclear cells

DOI:  https://doi.org/10.3892/etm.2022.11236
Cell Death Dis. 2022 Mar 30. 13(3): 282

Adiponectin receptor agonist ameliorates cardiac lipotoxicity via enhancing ceramide metabolism in type 2 diabetic mice.

Yaeni Kim, Ji Hee Lim, Eun Nim Kim, Yu Ah Hong, Hun-Jun Park, Sungjin Chung, Bum Soon Choi, Yong-Soo Kim, Ji Yong Park, Hye Won Kim, Cheol Whee Park.

Accumulation of lipids and their metabolites induces lipotoxicity in diabetic cardiomyopathy. Lowering ceramide concentration could reduce the impact of metabolic damage to target organs. Adiponectin improves lipotoxicity through its receptors (AdiopRs), which have sequence homology with ceramidase enzymes. Therefore, cardioprotective role of AdipoR agonism by AdipoRon was investigated. Sixteen-week-old male db/m and db/db mice were fed a diet containing AdipoRon for four weeks. Phenotypic and metabolic profiles with associated cellular signaling pathways involved in lipid metabolism were investigated in the mice heart and human cardiomyocytes to establish treatment effect of AdipoRon. AdipoRon ameliorated insulin resistance, fibrosis, M1-dominant inflammation, and apoptosis in association with reduced accumulations of free fatty acid, triglycerides, and TLR4-related ceramide in the heart. This resulted in overall reduction in the level of oxidative stress which ameliorated cardiac hypertrophy and its function. AdipoRon increased the expression of AdipoR1 and AdipoR2 via pAMPK/FoxO1-induced Akt phosphorylation resulting from a decrease in PP2A level. It also increased acid ceramidase activity which reduced ceramide and increased sphingosine-1 phosphate levels in the heart of db/db mice and cultured human cardiomyocytes. Consistent upregulation of AdipoRs and their downstream regulatory pathways involving pAMPK/PPARα/PGC-1α levels led to lipid metabolism enhancement, thereby improving lipotoxicity-induced peroxisome biogenesis and oxidative stress. AdipoRon might control oxidative stress, inflammation, and apoptosis in the heart through increased AdipoR expression, acid ceramidase activity, and activation of AMPK-PPARα/PGC-1α and related downstream pathways, collectively improving cardiac lipid metabolism, hypertrophy, and functional parameters.

DOI: https://doi.org/10.1038/s41419-022-04726-8
Front Pharmacol. 2022 ;13 824138

Cajaninstilbene Acid Ameliorates Acetaminophen-Induced Liver Injury Through Enhancing Sestrin2/AMPK-Mediated Mitochondrial Quality Control.

Mingzhu Yan, Suwei Jin, Yongguang Liu, Lisha Wang, Zhi Wang, Tianji Xia, Qi Chang.

  Acetaminophen (APAP)-induced liver injury (AILI) is the main cause of acute liver failure in the developed countries. The present study aimed to evaluate the therapeutic efficacy of cajaninstilbene acid (CSA), a major stilbene compound derived from the leaves of pigeon pea [Cajanus cajan (L.) Millsp.], against AILI. CSA (50, 75 mg/kg, p. o.) was administered to male C57BL/6 N mice 0.5 h after a toxic dose of APAP (300 mg/kg, i. p.). The direct effect of CSA on hepatocytes was tested on primary mouse hepatocytes. Serum transaminases, hematoxylin and eosin staining, TUNEL and propidium iodide staining were used to assess hepatic damage and cell death. The results demonstrated that APAP-induced liver injury was ameliorated by CSA, as evidenced by decreased alanine aminotransferase and aspartate aminotransferase levels in the serum, and fewer necrotic and apoptotic hepatocytes in vitro and in vivo. Consequently, the inflammation in response to APAP overdose was inhibited by CSA. Without affecting APAP metabolic activation, CSA interrupted the sustained JNK-Sab-ROS activation loop and alleviated oxidative stress. Additionally, CSA promoted mitochondrial quality control, including mitochondrial biogenesis and mitophagy, as revealed by increased PGC-1α, TFAM, LC3-Ⅱ, PINK1 and mitochondrial Parkin expression and decreased p62 expression. Further mechanistic investigations showed that independent of CAMKK2, LKB1-mediated AMPK activation, which was promoted by Sestrin2, might be responsible for the protective effect of CSA. Our study demonstrates that CSA alleviates APAP-induced oxidative stress and enhanced mitochondrial quality control through Sestrin2/AMPK activation, thereby protecting against AILI,.

Keywords:  AMPK; Sestrin2; acetaminophen; cajaninstilbene acid; liver injury; mitochondrial quality control

DOI:  https://doi.org/10.3389/fphar.2022.824138
Inflammopharmacology. 2022 Apr 01.

Dapagliflozin as an autophagic enhancer via LKB1/AMPK/SIRT1 pathway in ovariectomized/D-galactose Alzheimer's rat model.

Weam W Ibrahim, Ahmed S Kamel, Ahmed Wahid, Noha F Abdelkader.

  Autophagy and mitochondrial deficits are characteristics of early phase of Alzheimer's disease (AD). Sodium-glucose cotransporter-2 inhibitors have been nominated as a promising class against AD hallmarks. However, there are no available data yet to discuss the impact of gliflozins on autophagic pathways in AD. Peripherally, dapagliflozin's (DAPA) effect is mostly owed to autophagic signals. Thus, the goal of this study is to screen the power of DAPA centrally on LKB1/AMPK/SIRT1/mTOR signaling in the ovariectomized/D-galactose (OVX/D-Gal) rat model. Animals were arbitrarily distributed between 5 groups; the first group undergone sham operation, while remaining groups undergone OVX followed by D-Gal (150 mg/kg/day; i.p.) for 70 days. After 6 weeks, the third, fourth, and fifth groups received DAPA (1 mg/kg/day; p.o.); concomitantly with the AMPK inhibitor dorsomorphin (DORSO, 25 µg/rat, i.v.) in the fourth group and the SIRT1 inhibitor EX-527 (10 µg/rat, i.v.) in the fifth group. DAPA mitigated cognitive deficits of OVX/D-Gal rats, as mirrored in neurobehavioral task with hippocampal histopathological examination and immunohistochemical aggregates of p-Tau. The neuroprotective effect of DAPA was manifested by elevation of energy sensors; AMP/ATP ratio and LKB1/AMPK protein expressions along with autophagic markers; SIRT1, Beclin1, and LC3B expressions. Downstream the latter, DAPA boosted mTOR and mitochondrial function; TFAM, in contrary lessened BACE1. Herein, DORSO or EX-527 co-administration prohibited DAPA's actions where DORSO elucidated DAPA's direct effect on LKB1 while EX-527 mirrored its indirect effect on SIRT1. Therefore, DAPA implied its anti-AD effect, at least in part, via boosting hippocampal LKB1/AMPK/SIRT1/mTOR signaling in OVX/D-Gal rat model.

Keywords:  Alzheimer’s disease; Autophagy; Dapagliflozin; LKB1/AMPK signaling; Ovariectomized/D-galactose

DOI:  https://doi.org/10.1007/s10787-022-00973-5
Eur J Pharmacol. 2022 Mar 24. pii: S0014-2999(22)00177-7. [Epub ahead of print]922 174916

Acacetin attenuates diabetes-induced cardiomyopathy by inhibiting oxidative stress and energy metabolism via PPAR-α/AMPK pathway.

Fei Song, Yi-Jie Mao, Yu Hu, Shan-Shan Zhao, Ruiying Wang, Wei-Yin Wu, Gui-Rong Li, Yan Wang, Gang Li.

  Diabetic cardiomyopathy seriously affects the life quality of diabetic patients and can lead to heart failure and death in severe cases. Acacetin was reported to be an anti-oxidant and anti-inflammatory agent in several cardiovascular diseases. However, the effect of acacetin on diabetic cardiomyopathy was not understood. This study was designed to explore the therapeutic effect of acacetin on diabetic cardiomyopathy and the potential mechanism with in vitro and in vivo experimental techniques. In cultured neonatal rat cardiomyocytes and H9C2 cardiac cells, acacetin (0.3, 1, 3 μM) showed effective protection against high glucose-induced injury in a concentration-dependent manner. Acacetin countered high glucose-induced increase of Bax and decrease of Bcl-2, SOD1, and SOD2. In streptozotocin-induced rat diabetic cardiomyopathy model, treatment with acacetin prodrug (10 mg/kg, s.c., b.i.d.) significantly improved the cardiac function and reduced myocardial injury, and reversed the increase of serum MDA, Ang Ⅱ, and IL-6 levels and myocardial Bax and IL-6, and the decrease of serum SOD, indicating that acacetin plays a cardioprotective effect by inhibiting oxidative stress, inflammation, and apoptosis. In addition, both in vitro and in vivo experimental results showed that acacetin increased the expression of PPAR-α and pAMPK, indicating that PPAR-α and pAMPK are potential targets of acacetin for the protection against diabetic cardiomyopathy. This study demonstrates the new application of acacetin for treating diabetic cardiomyopathy.

Keywords:  AMPK; Acacetin; Apoptosis; Inflammation; PPAR-α

DOI:  https://doi.org/10.1016/j.ejphar.2022.174916
Curr Cancer Drug Targets. 2022 Mar 30.

Peroxisome Proliferator Activated Receptor Gamma Coactivator-1 Alpha: A Double-Edged Sword in Prostate Cancer.

Kun Zheng, Suzhen Chen, Xiaoyong Hu.

  Peroxisome proliferator activated receptor gamma coactivator-1 alpha (PGC-1α/PPARGC1A) is a pivotal transcriptional coactivator involved in the regulation of mitochondrial metabolism, including biogenesis and oxidative metabolism. PGC-1α is finely regulated by AMP-activated protein kinases (AMPKs), the role of which in tumors remains controversial to date. In recent years, a growing amount of research on PGC-1α and tumor metabolism has emphasized its importance in a variety of tumors, including prostate cancer (PCA). Compelling evidence has shown that PGC-1α may play dual roles in promoting and inhibiting tumor development under certain conditions. Therefore, a better understanding of the critical role of PGC-1α in PCA pathogenesis will provide new insights into targeting PGC-1α for the treatment of this disease. In this review, we highlight the procancer and anticancer effects of PGC-1α in PCA and aim to provide a theoretical basis for targeting AMPK/PGC-1α to inhibit the development of PCA. In addition, our recent findings provide a candidate drug target and theoretical basis for targeting PGC-1α to regulate lipid metabolism in PCA.

Keywords:  AMP-activated protein kinases; Prostate cancer; Warburg effect; adipocyte thermogenesis; mitochondrial metabolism; peroxisome proliferator activated receptor gamma coactivator-1alpha

DOI:  https://doi.org/10.2174/1568009622666220330194149
Biomed Pharmacother. 2022 Mar 29. pii: S0753-3322(22)00235-9. [Epub ahead of print]149 112847

The enhanced mitochondrial dysfunction by cantleyoside confines inflammatory response and promotes apoptosis of human HFLS-RA cell line via AMPK/Sirt 1/NF-κB pathway activation.

Jinrong Bai, Na Xie, Ya Hou, Xiaorui Chen, Yao Hu, Yi Zhang, Xianli Meng, Xiaobo Wang, Ce Tang.

  OBJECTIVE: Cantleyoside (CA) is a kind of iridoid glycosides in Pterocephalus hookeri (C. B. Clarke) Höeck. The purpose of this study was to investigate the effects of CA on human rheumatoid arthritis fibroblast synovial cells (HFLS-RA).METHODS: Cell proliferation of HFLS-RA was assessed by CCK-8. ELISA was used to detect cytokines NO, TNF-α, IL-1β/6, MCP-1, MMP-1/3/9 and metabolism-related ATPase activities and ATP levels. JC-1, DCFH-DA, Fluo-3 AM and Calcein AM probes were used to detect mitochondrial membrane potential (MMP), reactive oxygen species (ROS), Ca2+ and mitochondrial permeability conversion pore (MPTP), respectively. Isolated mitochondria assay was used to detect mitochondrial swelling. Oxygen consumption rate (OCR), extracellular acidification rate (ECAR) and real-time ATP production were measured using a Seahorse analyzer. Apoptosis was detected by TUNEL and Hoechst staining. Western blot was used to detect the expressions of AMPK/p-AMPK, Sirt 1, IκBα, NF-κB p65/p-NF-κB p65, Bcl-2 and Bax. Cytoplasmic nuclear isolation was also performed to detect the translocation of NF-κB.
RESULTS: CA significantly suppressed cell proliferation and the levels of NO, TNF-α, IL-1β/6, MCP-1 and MMP-1/3/9 in HFLS-RA. In addition, CA promoted the apoptosis of HFLS-RA by increasing TUNEL and Hoechst positive cells and the ratio of Bax/Bcl-2. Inhibition of energy metabolism in HFLS-RA by CA reduced OCR, ECAR and real-time ATP generation rate. Importantly, CA promoted p-AMPK and Sirt 1 expression, inhibited IκBα degradation to reduce p-NF-κB and translocation.
CONCLUSION: The results suggest that CA activates the AMPK/Sirt 1/NF-κB pathway by promoting mitochondrial dysfunction, thereby exerting anti-inflammatory and pro-apoptotic effects.

Keywords:  AMPK/Sirt 1/NF-κB; Cantleyoside; HFLS-RA; LPS; Rheumatoid arthritis

DOI:  https://doi.org/10.1016/j.biopha.2022.112847
Pharm Biol. 2022 Dec;60(1): 729-742

β-Hydroxyisovalerylshikonin regulates macrophage polarization via the AMPK/Nrf2 pathway and ameliorates sepsis in mice.

Tao Pan, Yabin Chang, Min He, Zehui He, Jun Jiang, Xinling Ren, Fang Zhang.

  CONTEXT: The potential anti-inflammatory bioactivities of β-hydroxyisovalerylshikonin (β-HIVS) remain largely unknown.OBJECTIVE: This study investigated the anti-inflammatory effects and underlying mechanisms of β-HIVS.
MATERIALS AND METHODS: RAW 264.7 cells stimulated with LPS (100 ng/mL) for 24 h were treated with the non-cytotoxic doses of β-HIVS (0.5 or 1 μM, determined by MTT and Trypan blue staining), qRT-PCR and FCM assay were used to examine macrophage polarization transitions. Western blotting was used to evaluate the activation of the AMPK/Nrf2 pathway. In vivo, C57BL/6 mice were randomly divided into vehicle control, LPS (10 mg/kg), and β-HIVS (2.5 mg/kg) combined with LPS (10 mg/kg) groups, blood samples, BALF, and lung tissues of mice were subjected to ELISA, qRT-PCR, FCM, and H&E staining.
RESULTS: β-HIVS (1 μM) inhibited LPS-induced expression of M1 macrophage markers (TNF-α: 0.29-fold, IL-1β: 0.32-fold), promoted the expression of M2 macrophage markers (CD206: 3.14-fold, Arginase-1: 3.98-fold) in RAW 264.7 cells; mechanistic studies showed that β-HIVS increased the expression of nuclear Nrf2 (2.04-fold) and p-AMPK (3.65-fold) compared with LPS group (p < 0.05). In vivo, β-HIVS decreased the levels of pro-inflammatory cytokines (TNF-α: 1130.41 vs. 334.88 pg/mL, IL-1β: 601.89 vs. 258.21 pg/mL in serum; TNF-α: 893.07 vs. 418.21 pg/mL, IL-1β: 475.22 vs. 298.54 pg/mL in BALF), decreased the proportion of M1 macrophages (77.83 vs. 68.53%) and increased the proportion of M2 macrophages (13.55 vs. 19.56%) in BALF, and reduced lung tissue damage and septic mice survival (p < 0.05).
CONCLUSIONS: These results indicate that β-HIVS may be a new potential anti-inflammatory agent.

Keywords:  Chinese herb extract; anti-inflammatory effect; lipopolysaccharide; non‑cytotoxic dose

DOI:  https://doi.org/10.1080/13880209.2022.2046111
J Ethnopharmacol. 2022 Mar 26. pii: S0378-8741(22)00276-8. [Epub ahead of print] 115237

Pretreatment of hydroethanolic extract of Dillenia indica L. attenuates oleic acid induced NAFLD in HepG2 cells via modulating SIRT-1/p-LKB-1/AMPK, HMGCR & PPAR-α signaling pathways.

M S Poornima, G Sindhu, Abraham Billu, C R Sruthi, P Nisha, Pinku Gogoi, Gakul Baishya, K G Raghu.

  ETHNOPHARMACOLOGICAL RELEVANCE: Dillenia indica L. is an edible plant from the Dilleniaceae family present in the forest of India and other Asian countries. Different parts of this plant are being used in the traditional system of medicines for various diseases like diabetes, indigestion, asthma, jaundice, and rheumatic pain by various rural communities. This plant is very common among Khamptis traditional healers, the rural community of the Dhemaji district of Assam, ethnic communities of Dibru-Saikhowa Biosphere Reserve of Northeast, India for various medicinal uses. It is observed as a 'vat' suppressant and 'pitta' boosting medicine in Ayurveda.AIM OF THE STUDY: The aim of this research was to evaluate the effect of hydroethanolic extract of Dillenia indica leaf (DI-HET) against non-alcoholic fatty liver disease (NAFLD) as it is reported effective against jaundice in traditional medicine. We are also planning to see the various molecular mechanisms responsible for its effect if it is efficacious.
STUDY DESIGN/METHOD: An in vitro model for NAFLD was employed in this study. For this HepG2 cells were incubated with 100 μM of oleic acid (OA) for 24 h. For evaluation of the effect of DI-HET, the extracts (5 or 10 μg/mL) were pretreated to the OA group. Fenofibrate was the positive control. Various parameters relevant to lipogenesis and β-oxidation of fatty acids like intracellular lipid accumulation, reactive oxygen species (ROS), mitochondrial stress, and key proteins were studied.
RESULTS: DI-HET significantly reduced the intracellular lipid accumulation in OA treated cells. And also substantially decreased the expression of lipogenic proteins and increased β-oxidation in the OA group. OA induced ROS generation was found to reduce with DI-HET treatment. Western blot analysis showed that the expression of LXR-α, SREBP-1C, SREBP-2, HMGCR, FAS, CD-36, and ACOX-1 were downregulated while that of SIRT-1, p-LKB-, p-AMPK, p-ACC, CPT-1, and PPAR-α upregulated in DI-HET treatment. LCMS/MS analysis showed the presence of polyphenols like naringenin, catechin, epicatechin, shikimic acid, syringic acid, vanillic acid, and kaempferol.
CONCLUSION: These results suggest that DI-HET is effective against NAFLD by activation of the SIRT-1/p-LKB-1/AMPK signaling pathway via polyphenols present in the extract.

Keywords:  AMPK; Dillenia indica L.; HepG2 cells; NAFLD; PPAR-α

DOI:  https://doi.org/10.1016/j.jep.2022.115237
Food Chem. 2022 Mar 25. pii: S0308-8146(22)00774-9. [Epub ahead of print]386 132812

Prooxidant activity-based guideline for a beneficial combination of (-)-epigallocatechin-3-gallate and chlorogenic acid.

Lumin Yang, Lijie Jia, Xiuli Li, Ke Zhang, Xiaoxiao Wang, Yufeng He, Meng Hao, Margaret P Rayman, Jinsong Zhang.

  In the current study, the prooxidant activities of (-)-epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CGA) were systematically compared both in multiple in vitro models and in mice. At equimolar concentrations in vitro and in vivo, EGCG displayed powerful prooxidant effects though CGA exhibited none. In vitro, though CGA and EGCG synergistically produced hydrogen peroxide, CGA was able to scavenge hydroxyl radicals generated by EGCG/copper. Consistent with the selective modulation of reactive oxygen species produced from EGCG, CGA lowered hepatotoxicity but did not perturb hepatic AMPK activation nor the increase of hepatic Nrf2-associated proteins induced by high-dose EGCG. CGA, along with low-dose EGCG, synergistically activated hepatic AMPK and increased hepatic Nrf2-associated proteins without causing toxicity in mice. This proof-of-principle study suggests that polyphenols with potent prooxidant activities (e.g., EGCG) together with antioxidant polyphenols with noticeably low prooxidant activities (e.g., CGA) may yield health benefits with a low risk of side effects.

Keywords:  AMPK; Chlorogenic acid; EGCG; Nrf2; Prooxidant activity; Synergistic effect

DOI:  https://doi.org/10.1016/j.foodchem.2022.132812
Respir Physiol Neurobiol. 2022 Mar 24. pii: S1569-9048(22)00050-7. [Epub ahead of print]301 103891

MiR-21 modulates proliferation and apoptosis of human airway smooth muscle cells by regulating autophagy via PARP-1/AMPK/mTOR signalling pathway.

Peng Sun, Shiqing Zhang, Di Wu, Yan Qian, Xinru Xiao, Qian Zhang.

  Superfluous human airway smooth muscle (HASM) cell proliferation is an important pathological feature of airway remodelling in asthma. This study aimed to determine whether miR-21 is involved in the regulation of HASM cell survival. Overexpressed miR-21 inhibited HASM cell apoptosis and autophagy and promoted proliferation, whereas a miR-21 inhibitor exerted the opposite effects (P < 0.05). Overexpressed poly (ADP-ribose) polymerase-1 (PARP-1) promoted apoptosis and inhibited proliferation of HASM cells (P < 0.05). Dual-luciferase assays confirmed that miR-21 directly targeted poly (ADP-ribose) polymerase-1 (PARP-1) mRNA (P < 0.05). Silencing PARP-1 based on miR-21 downregulation mimicked the role of 3-methyladenine (3-MA), an autophagy inhibitor (P < 0.05). Overexpressed PARP-1 reversed the effects of miR-21 on HASM cells, somewhat dependently on PARP-1-induced enhanced autophagy, which we elucidated by 3-MA block (P < 0.05). MicroRNA-21 mimics reduced AMPK and increased mTOR signalling by downregulating PARP-1, and a miR-21 inhibitor exerted the opposite effects (P < 0.05). Collectively, miR-21 inhibitor could upregulate PARP-1 in HASM cells to promote autophagy and thus inhibit proliferation and promote apoptosis that might be mediated by the AMPK/mTOR signalling pathway.

Keywords:  AMPK/mTOR signalling pathway; Asthma; Autophagy; Human airway smooth muscle cell; MiR-21; Poly (ADP-ribose) polymerase-1

DOI:  https://doi.org/10.1016/j.resp.2022.103891
J Exp Clin Cancer Res. 2022 Mar 30. 41(1): 116

Cholesterol sensor SCAP contributes to sorafenib resistance by regulating autophagy in hepatocellular carcinoma.

Danyang Li, Yingcheng Yao, Yuhan Rao, Xinyu Huang, Li Wei, Zhimei You, Guo Zheng, Xiaoli Hou, Yu Su, Zac Varghese, John F Moorhead, Yaxi Chen, Xiong Z Ruan.

  BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most malignant tumors and the fourth leading cause of cancer-related death worldwide. Sorafenib is currently acknowledged as a standard therapy for advanced HCC. However, acquired resistance substantially limits the clinical efficacy of sorafenib. Therefore, further investigations of the associated risk factors are highly warranted.METHODS: We analysed a group of 78 HCC patients who received sorafenib treatment after liver resection surgery. The expression of SCAP and its correlation with sorafenib resistance in HCC clinical samples were determined by immunohistochemical analyses. Overexpression and knockdown approaches in vitro were used to characterize the functional roles of SCAP in regulating sorafenib resistance. The effects of SCAP inhibition in HCC cell lines were analysed in proliferation, apoptosis, and colony formation assays. Autophagic regulation by SCAP was assessed by immunoblotting, immunofluorescence and immunoprecipitation assays. The combinatorial effect of a SCAP inhibitor and sorafenib was tested using nude mice.
RESULTS: Hypercholesterolemia was associated with sorafenib resistance in HCC treatment. The degree of sorafenib resistance was correlated with the expression of the cholesterol sensor SCAP and consequent deposition of cholesterol. SCAP is overexpressed in HCC tissues and hepatocellular carcinoma cell lines with sorafenib resistance, while SCAP inhibition could improve sorafenib sensitivity in sorafenib-resistant HCC cells. Furthermore, we found that SCAP-mediated sorafenib resistance was related to decreased autophagy, which was connected to decreased AMPK activity. A clinically significant finding was that lycorine, a specific SCAP inhibitor, could reverse acquired resistance to sorafenib in vitro and in vivo.
CONCLUSIONS: SCAP contributes to sorafenib resistance through AMPK-mediated autophagic regulation. The combination of sorafenib and SCAP targeted therapy provides a novel personalized treatment to enhance sensitivity in sorafenib-resistant HCC.

Keywords:  Autophagy; Hepatocellular carcinoma (HCC); Lycorine; SCAP; Sorafenib resistant

DOI:  https://doi.org/10.1186/s13046-022-02306-4