bims-amsmem 2022-03-27 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022‒03‒27
28 papers selected by
Dipsikha Biswas, Københavns Universitet

Adenosine Monophosphate Activated Protein Kinase (AMPK) enhances chemotherapy response in Acute Myeloid Leukemia (AML).
AMPK Activation Is Indispensable for the Protective Effects of Caloric Restriction on Left Ventricular Function in Postinfarct Myocardium.
Angelica gigas NAKAI and Its Active Compound, Decursin, Inhibit Cellular Injury as an Antioxidant by the Regulation of AMP-Activated Protein Kinase and YAP Signaling.
AMP-activated protein kinase(AMPK) channel: A Global Bibliometric analysis From 2012 to 2021.
AMPK Activator O304 Protects Against Kidney Aging Through Promoting Energy Metabolism and Autophagy.
Attenuation of the Counter-Regulatory Glucose Response in CVLM C1 Neurons: A Possible Explanation for Anorexia of Aging.
Natural (dihydro)phenanthrene plant compounds are direct activators of AMPK through its allosteric drug and metabolite binding site.
Suppression of Adipogenesis and Fat Accumulation by Vitexin Through Activation of Hedgehog Signaling in 3T3-L1 Adipocytes.
Zingerone ameliorates non-alcoholic fatty liver disease in rats by activating AMPK.
Tumor Cell Glycolysis-At the Crossroad of Epithelial-Mesenchymal Transition and Autophagy.
Tanshinone 1 prevents high fat diet-induced obesity through activation of brown adipocytes and induction of browning in white adipocytes.
Nuclear receptor 4A1 (NR4A1) silencing protects hepatocyte against hypoxia-reperfusion injury in vitro by activating liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling.
GANT61 elevates chemosensitivity to cisplatin through regulating the Hedgehog, AMPK and cAMP pathways in ovarian cancer.
Microwave radiation induces neuronal autophagy through miR-30a-5p/AMPKα2 signal pathway.
The C-glucosyl flavone isoorientin pretreatment attenuates the methylglyoxal-induced mitochondrial dysfunction in the human neuroblastoma SH-SY5Y cells: role for the AMPK-PI3K/Akt/Nrf2/γ-GCL/GSH axis.
Combination Effects of Metformin and a Mixture of Lemon Balm and Dandelion on High-Fat Diet-Induced Metabolic Alterations in Mice.
Ca2+/Calmodulin-Dependent Protein Kinase II Inhibits Hepatitis B Virus Replication from cccDNA via AMPK Activation and AKT/mTOR Suppression.
Editorial: Metabolism and Cell Adhesion in Cancer.
Puerarin attenuates LPS-induced inflammatory injury in gastric epithelial cells by repressing NLRP3 inflammasome-mediated apoptosis.
Delivery of astragalus polysaccharide by ultrasound microbubbles attenuate doxorubicin-induced cardiomyopathy in rodent animals.
Metformin synergistically increases the anticancer effects of lapatinib through induction of apoptosis and modulation of Akt/AMPK pathway in SK-BR3 breast cancer cell line.
Growth hormone receptor gene influences mitochondrial function and chicken lipid metabolism by AMPK-PGC1α-PPAR signaling pathway.
SARS-CoV-2 Spike Protein 1 Activates Microvascular Endothelial Cells and Complement System Leading to Platelet Aggregation.
Baicalin promotes the activation of brown and white adipose tissue through AMPK/PGC1α pathway.
miR-296-5p promotes autophagy in mouse LS8 cells under excessive fluoride via AMPK/ULK1 pathways.
Empagliflozin attenuates cardiac microvascular ischemia/reperfusion through activating the AMPKα1/ULK1/FUNDC1/mitophagy pathway.
Hepatic IRF3 fuels dysglycemia in obesity through direct regulation of Ppp2r1b.
Metformin and Cancer Hallmarks: Molecular Mechanisms in Thyroid, Prostate and Head and Neck Cancer Models.

Cancer Lett. 2022 Mar 20. pii: S0304-3835(22)00142-2. [Epub ahead of print]535 215659

Adenosine Monophosphate Activated Protein Kinase (AMPK) enhances chemotherapy response in Acute Myeloid Leukemia (AML).

Lais Ghiraldeli, Rebecca Anderson, Kristin Pladna, Timothy S Pardee.

Adenosine monophosphate activated protein kinase (AMPK) is a master regulator of cell metabolism and is involved in cancer as both a tumor suppressor and a source of resistance to metabolic stress. The role of AMPK in response to chemotherapy has been examined in solid tumor models but remains unclear in acute myeloid leukemia (AML). To determine the role of AMPK in chemotherapy response, AML cell lines were generated lacking AMPK activity. AMPK knock out cells demonstrated significant resistance to cytarabine and doxorubicin both in vitro and in vivo. Mitochondrial mass and function were unchanged in AMPK knockout cells. Mechanistically, AMPK knock out cells demonstrated a diminished DNA damage response with significantly lower γH2AX foci, p53 and p21 induction as well as decreased apoptosis following chemotherapy exposure. Most importantly, TCGA datasets revealed that patients expressing low levels of the PRKAA1 subunit of AMPK had significantly shorter survival. Finally, AML cells were sensitized to chemotherapy with the addition of the AMPK activator AICAR. These data demonstrate that AMPK sensitizes AML cells to chemotherapy and suggests a contribution of the cellular metabolic state to cell fate decisions ultimately affecting therapy response.

DOI: https://doi.org/10.1016/j.canlet.2022.215659
Biology (Basel). 2022 Mar 16. pii: 448. [Epub ahead of print]11(3):

AMPK Activation Is Indispensable for the Protective Effects of Caloric Restriction on Left Ventricular Function in Postinfarct Myocardium.

Bernd Niemann, Ruping Pan, Hassan Issa, Andreas Simm, Rainer Schulz, Susanne Rohrbach.

  BACKGROUND: Caloric restriction (CR) extends lifespan in many species, including mammals. CR is cardioprotective in senescent myocardium by correcting pre-existing mitochondrial dysfunction and apoptotic activation. Furthermore, it confers cardioprotection against acute ischemia-reperfusion injury. Here, we investigated the role of AMP-activated protein kinase (AMPK) in mediating the cardioprotective CR effects in failing, postinfarct myocardium.METHODS: Ligation of the left coronary artery or sham operation was performed in rats and mice. Four weeks after surgery, left ventricular (LV) function was analyzed by echocardiography, and animals were assigned to different feeding groups (control diet or 40% CR, 8 weeks) as matched pairs. The role of AMPK was investigated with an AMPK inhibitor in rats or the use of alpha 2 AMPK knock-out mice.
RESULTS: CR resulted in a significant improvement in LV function, compared to postinfarct animals receiving control diet in both species. The improvement in LV function was accompanied by a reduction in serum BNP, decrease in LV proapoptotic activation, and increase in mitochondrial biogenesis in the LV. Inhibition or loss of AMPK prevented most of these changes.
CONCLUSIONS: The failing, postischemic heart is protected from progressive loss of LV systolic function by CR. AMPK activation is indispensable for these protective effects.

Keywords:  AMPK; caloric restriction; heart failure; ischemia; mitochondria

DOI:  https://doi.org/10.3390/biology11030448
Molecules. 2022 Mar 13. pii: 1858. [Epub ahead of print]27(6):

Angelica gigas NAKAI and Its Active Compound, Decursin, Inhibit Cellular Injury as an Antioxidant by the Regulation of AMP-Activated Protein Kinase and YAP Signaling.

Yu-Rim Song, Boyun Jang, Sung-Min Lee, Su-Jin Bae, Seon-Been Bak, Young-Woo Kim.

  Natural products and medicinal herbs have been used to treat various human diseases by regulating cellular functions and metabolic pathways. Angelica gigas NAKAI (AG) helps regulate pathological processes in some medical fields, including gastroenterology, gynecology, and neuropsychiatry. Although some papers have reported its diverse indications, the effects of AG against arachidonic acid (AA)+ iron and carbon tetrachloride (CCl4) have not been reported. In HepG2 cells, AA+ iron induced cellular apoptosis and mitochondrial damage, as assessed by mitochondrial membrane permeability (MMP) and the expression of apoptosis-related proteins. On the other hand, AG markedly inhibited these detrimental phenomena and reactive oxygen species (ROS) production induced by AA+ iron. AG activated the liver kinase B1 (LKB1)-dependent AMP-activated protein kinase (AMPK), which affected oxidative stress in the cells. Moreover, AG also regulated the expression of yes-associated protein (YAP) signaling as mediated by the AMPK pathways. In mice, an oral treatment of AG protected against liver toxicity induced by CCl4, as indicated by the plasma and histochemical parameters. Among the compounds in AG, decursin had antioxidant activity and affected the AMPK pathway. In conclusion, AG has antioxidant effects in vivo and in vitro, indicating that natural products such as AG could be potential candidate for the nutraceuticals to treat various disorders by regulating mitochondrial dysfunction and cellular metabolic pathways.

Keywords:  AMPK; Angelica gigas NAKAI; YAP; dementia; mitochondria; neuropsychiatry

DOI:  https://doi.org/10.3390/molecules27061858
Channels (Austin). 2022 Dec;16(1): 60-71

AMP-activated protein kinase(AMPK) channel: A Global Bibliometric analysis From 2012 to 2021.

Tianyi Lyu, Chuanxi Tian, Tianyang Tan, Jiaxuan Lyu, Kang Yan, Xirui Zhao, Ruoshui Wang, Chaoyang Zhang, Meng Liu, Yulong Wei.

  In recent years, AMPK channel has gained considerable attention in a variety of research areas, and several academic journals have published articles on AMPK research. However, few attempts have been made to thoroughly assess the scientific output and current status systematically in this topic from a worldwide viewpoint. As a result, it is critical to adopt an appropriate visualization method to reveal the global status, future research trends, and hotspots in AMPK channel research. To investigate research hotspots/frontiers in certain domains, bibliometric analysis has been frequently utilized to determine the productivity of nations, institutions, authors, and the frequency of keywords. In this work, we used CiteSpace and VOSviewer to conduct a bibliometric analysis of AMPK channel studies from 2012 to 2021 in order to perform researchers with some directions for AMPK channel research.

Keywords:  AMPK; bibliometric analysis; cancer; metabolic diseases; stroke

DOI:  https://doi.org/10.1080/19336950.2022.2049543
Front Pharmacol. 2022 ;13 836496

AMPK Activator O304 Protects Against Kidney Aging Through Promoting Energy Metabolism and Autophagy.

Mingsheng Zhu, Weiwei Shen, Jiemei Li, Nan Jia, Yabing Xiong, Jinhua Miao, Chao Xie, Qiyan Chen, Kunyu Shen, Ping Meng, Xiaolong Li, Qinyu Wu, Shan Zhou, Maosheng Wang, Yaozhong Kong, Lili Zhou.

  Aging is an important risk factor for kidney injury. Energy homeostasis plays a key role in retarding aging, and mitochondria are responsible for energy production. In the kidney, renal tubular cells possess high abundance of mitochondria to meet the high energy consumption. AMPK is an evolutionarily conserved serine/threonine kinase which plays a central role in maintaining energy homeostasis and mitochondrial homeostasis. Besides that, AMPK also commands autophagy, a clearing and recycling process to maintain cellular homeostasis. However, the effect of AMPK activators on kidney aging has not been fully elucidated. To this end, we testified the effects of O304, a novel direct AMPK activator, in naturally aging mice model and D-Galactose (D-Gal)-treated renal tubular cell culture. We identified that O304 beneficially protects against cellular senescence and aged-related fibrosis in kidneys. Also, O304 restored energy metabolism, promoted autophagy and preserved mitochondrial homeostasis. Transcriptomic sequencing also proved that O304 induced fatty acid metabolism, mitochondrial biogenesis and ATP process, and downregulated cell aging, DNA damage response and collagen organization. All these results suggest that O304 has a strong potential to retard aged kidney injury through regulating AMPK-induced multiple pathways. Our results provide an important therapeutic approach to delay kidney aging.

Keywords:  AMPK; O304; autophagy; energy metabolism; kidney aging

DOI:  https://doi.org/10.3389/fphar.2022.836496
Biomolecules. 2022 Mar 14. pii: 449. [Epub ahead of print]12(3):

Attenuation of the Counter-Regulatory Glucose Response in CVLM C1 Neurons: A Possible Explanation for Anorexia of Aging.

Hajira Ramlan, Hanafi Ahmad Damanhuri.

  This study aimed to determine the effect of age on CVLM C1 neuron glucoregulatory proteins in the feeding pathway. Male Sprague Dawley rats aged 3 months and 24 months old were divided into two subgroups: the treatment group with 2-deoxy-d-glucose (2DG) and the control group. Rat brains were dissected to obtain the CVLM region of the brainstem. Western blot was used to determine protein expression of tyrosine hydroxylase (TH), phosphorylated TH at Serine40 (pSer40TH), AMP-activated protein kinase (AMPK), phosphorylated AMPK (phospho AMPK), and neuropeptide Y Y5 receptors (NPY5R) in CVLM samples. Immunofluorescence was used to determine TH-, AMPK-, and NPY5R-like immunoreactivities among other brain coronal sections. Results obtained denote a decrease in basal TH phosphorylation levels and AMPK proteins and an increase in TH proteins among aged CVLM neurons. Increases in the basal immunoreactivity of TH+, AMPK+, NPY5R+, TH+/AMPK+, and TH+/NPY5R+ were also observed among old rats. Young treatment-group rats saw a decrease in TH phosphorylation and AMPK proteins following 2DG administration, while an increase in AMPK phosphorylation and a decrease in TH proteins were found among the old-treatment-group rats. These findings suggest the participation of CVLM C1 neurons in counter-regulatory responses among young and old rats. Altering protein changes in aged CVLM C1 neurons may attenuate responses to glucoprivation, thus explaining the decline in food intake among the elderly.

Keywords:  anorexia of aging; catecholaminergic neurons; caudal ventrolateral medulla; feeding response; glucoprivation

DOI:  https://doi.org/10.3390/biom12030449
J Biol Chem. 2022 Mar 21. pii: S0021-9258(22)00292-7. [Epub ahead of print] 101852

Natural (dihydro)phenanthrene plant compounds are direct activators of AMPK through its allosteric drug and metabolite binding site.

Matthew J Sanders, Yann Ratinaud, Katyayanee Neopane, Nicolas Bonhoure, Emily A Day, Olivier Ciclet, Steve Lassueur, Martine Naranjo Pinta, Maria Deak, Benjamin Brinon, Stefan Christan, Gregory R Steinberg, Denis Barron, Kei Sakamoto.

  AMP-activated protein kinase (AMPK) is a central energy sensor that coordinates the response to energy challenges to maintain cellular ATP levels. AMPK is a potential therapeutic target for treating metabolic disorders, and several direct synthetic activators of AMPK have been developed that show promise in pre-clinical models of type 2 diabetes. These compounds have been shown to regulate AMPK through binding to a novel allosteric drug and metabolite (ADaM) binding site on AMPK, and it is possible that other molecules might similarly bind this site. Here we performed a high throughput screen with natural plant compounds to identify such direct allosteric activators of AMPK. We identified a natural plant dihydrophenathrene, Lusianthridin, which allosterically activates and protects AMPK from dephosphorylation by binding to the ADaM site. Similar to other ADaM-site activators, Lusianthridin showed preferential activation of AMPKβ1-containing complexes in intact cells, and was unable to activate an AMPKβ1 S108A mutant. We also found that Lusianthridin dose-dependently increased phosphorylation of acetyl-CoA carboxylase (ACC) in mouse primary hepatocytes, which led to a corresponding decrease in de novo lipogenesis. This ability of Lusianthridin to inhibit lipogenesis was impaired in hepatocytes from S108A knock-in mice and mice bearing a mutation at the AMPK phosphorylation site of ACC1/2. Finally, we show that activation of AMPK by natural compounds extends to several analogues of Lusianthridin and the related chemical series, phenanthrenes. The emergence of natural plant compounds that regulate AMPK through the ADaM-site raises the distinct possibility that other natural compounds share a common mechanism of regulation.

Keywords:  AMP-activated protein kinase; Lusianthridin; Lusianthrin; allosteric drug and metabolite binding site; lipogenesis

DOI:  https://doi.org/10.1016/j.jbc.2022.101852
J Med Food. 2022 Mar;25(3): 313-323

Suppression of Adipogenesis and Fat Accumulation by Vitexin Through Activation of Hedgehog Signaling in 3T3-L1 Adipocytes.

Shuai Qiu, Jing Chen, Jin Tae Kim, Yimeng Zhou, Ji Hyun Moon, Seung Beom Lee, Ho Jin Park, Hong Jin Lee.

  Many studies have demonstrated that adipogenesis is associated with obesity, and the Hedgehog (Hh) signaling pathway regulates adipogenesis and obesity. Following the screening study of the chemical library evaluating the effect of vitexin on Gli1 transcriptional activity, vitexin was chosen as a candidate for antiadipogenic efficacy. Vitexin significantly reduced lipid accumulation and suppressed C/EBPα (CCAAT/enhancer-binding protein α) and PPARγ (peroxisome proliferator-activated receptor γ) expression, which are known as key adipogenic factors in the early stages of adipogenesis by activating Hh signaling. Furthermore, Hh inhibitor GANT61 reversed the effect of AMP-activated protein kinase (AMPK) activator AICAR (5-aminoimidazole-4-carboxamide ribonucleotide), indicating that Hh signaling is an upstream regulator of AMPK in 3T3-L1 cells. Vitexin suppressed adipogenesis by regulating Hh signaling and phosphorylation of AMPK, leading to the inhibition of fat formation. These results suggest that vitexin can be considered a potent dietary agent in alleviating lipid accumulation and obesity.

Keywords:  AMPK; adipocyte; adipogenesis; hedgehog; vitexin

DOI:  https://doi.org/10.1089/jmf.2021.K.0163
J Food Biochem. 2022 Mar 25. e14149

Zingerone ameliorates non-alcoholic fatty liver disease in rats by activating AMPK.

Heitham M Mohammed.

  This study was conducted to test the protective potential of Zingerone against a high-fat diet (HFD)-mediated non-alcoholic fatty liver disease (NAFLD) development in rats and examined in this protection is mediated modulating AMP-activated protein kinase (AMPK). Animals were segregated based on their diet and treatment into four groups (n = 6 each): (a) fed standard diet (STD), (b) treated with Zingerone (100 mg/kg), (c) fed HFD, (d) HFD + Zingerone (100 mg/kg), and (e) HFD + Zingerone (100 mg/kg) + compound c (CC) (an AMPK inhibitor) (0.2 mg/kg). The treatment with Zingerone attenuated the gain in final body weights, preserved liver structure, and downregulated the transcription of Bax and cleaved caspase-3. In the HFD and STD-fed rats, Zingerone reduced levels of fasting glucose and insulin and circulatory levels of cholesterol (CHOL) and triglycerides (TGs). Concomitantly, Zingerone enhanced glutathione (GSH) and superoxide dismutase (SOD) levels, depleted levels of malondialdehyde (MDA), and enhanced the nuclear levels of the nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, it lowered the levels of inflammatory cytokines and the nuclear levels of the nuclear factor kappa beta p65 (NF-κB p65). All these biochemical changes were associated with an increment in the phosphorylation of AMPK (p-AMPK) (activation) and reduced mRNA levels of SREBP1 and SREBP2. All observed effects afforded by Zingerone were abolished by CC. In conclusion, Zingerone prevents hepatic oxidative stress, inflammation, and apoptosis by activating AMPK. PRACTICAL APPLICATIONS: The findings of this study identified Zingerone, isolated from ginger, as a very effective drug that not only can attenuate fasting hyperglycemia and hyperlipidemia, but also prevent hepatic deposition, steatosis, and oxidative damage induced by high-fat-fed rats by activating the AMPK/Nrf2 antioxidant axis and concomitant suppression of SREBP1, SREBp2, and NF-κB p65. These data list Zingerone as a potent stimulator of AMPK which suggests an effective strategy to treat and alleviate NAFLD and encourages further translational and clinical trials.

Keywords:  AMPK; HFD; NAFLD; NF-κB; Nrf2; SREBP1c; Zingerone; lipids; liver

DOI:  https://doi.org/10.1111/jfbc.14149
Cells. 2022 Mar 18. pii: 1041. [Epub ahead of print]11(6):

Tumor Cell Glycolysis-At the Crossroad of Epithelial-Mesenchymal Transition and Autophagy.

Fabrizio Marcucci, Cristiano Rumio.

  Upregulation of glycolysis, induction of epithelial-mesenchymal transition (EMT) and macroautophagy (hereafter autophagy), are phenotypic changes that occur in tumor cells, in response to similar stimuli, either tumor cell-autonomous or from the tumor microenvironment. Available evidence, herein reviewed, suggests that glycolysis can play a causative role in the induction of EMT and autophagy in tumor cells. Thus, glycolysis has been shown to induce EMT and either induce or inhibit autophagy. Glycolysis-induced autophagy occurs both in the presence (glucose starvation) or absence (glucose sufficiency) of metabolic stress. In order to explain these, in part, contradictory experimental observations, we propose that in the presence of stimuli, tumor cells respond by upregulating glycolysis, which will then induce EMT and inhibit autophagy. In the presence of stimuli and glucose starvation, upregulated glycolysis leads to adenosine monophosphate-activated protein kinase (AMPK) activation and autophagy induction. In the presence of stimuli and glucose sufficiency, upregulated glycolytic enzymes (e.g., aldolase or glyceraldehyde 3-phosphate dehydrogenase) or decreased levels of glycolytic metabolites (e.g., dihydroxyacetone phosphate) may mimic a situation of metabolic stress (herein referred to as "pseudostarvation"), leading, directly or indirectly, to AMPK activation and autophagy induction. We also discuss possible mechanisms, whereby glycolysis can induce a mixed mesenchymal/autophagic phenotype in tumor cells. Subsequently, we address unresolved problems in this field and possible therapeutic consequences.

Keywords:  AMPK; EMT; autophagy; glycolysis; mTOR; starvation

DOI:  https://doi.org/10.3390/cells11061041
Life Sci. 2022 Mar 21. pii: S0024-3205(22)00188-6. [Epub ahead of print] 120488

Tanshinone 1 prevents high fat diet-induced obesity through activation of brown adipocytes and induction of browning in white adipocytes.

Dae Young Jung, Nanjoo Suh, Myeong Ho Jung.

  AIM: Increasing brown adipocytes activity and inducting browning of white adipocytes are potential therapeutic targets for the treatment of obesity. In the present study, we investigated the effects of Tanshinone 1 (Tan 1), a major compound from Salvia miltiorrhiza Bunge, on the activation of brown adipocytes and browning of white adipocytes in vivo and in vitro.MATERIALS AND METHODS: Expression of genes associated with brown adipocyte function including thermogenesis, mitochondria biogenesis and fatty acid oxidation was examined in brown adipose tissue (BAT) and white adipose tissue (WAT) of high fat diet (HFD)-fed obese mice administrated with Tan 1 or in immortalized brown adipocytes (iBAs) and 3T3-L1 adipocytes treated with Tan 1. Mitochondria DNA (mtDNA) content, lipolysis and phosphorylated AMP-activated protein kinase (AMPK) were further assessed in Tan 1 treated-iBAs and 3T3-L1 adipocytes.
KEY FINDINGS: The administration of Tan 1 protected against HFD-induced obesity in mice, which was associated with enhanced expression of brown adipocyte function-related genes in BAT and WAT. Tan 1 treatment also upregulated brown adipocyte function-related genes in iBA and induced beige adipocytes genes in 3T3-L1 adipocytes, resulting in increased mtDNA content and lipolysis. Tan 1 activated AMPK in BAT and WAT of HFD-fed obese mice as well as in iBAs and 3T3-L1 adipocytes. Inhibition of AMPK by compound C prevented Tan 1-induced expression of beige adipocytes genes.
SIGNIFICANCE: These results indicate that Tan 1 activates brown adipocytes and induces browning of white adipocytes, which may contribute to anti-obesity activity of Tan 1.

Keywords:  AMP-activated protein kinase; Brown adipocytes; Browning; Energy expenditure; Fatty acid oxidation; Mitochondrial biogenesis; Obesity; Thermogenesis

DOI:  https://doi.org/10.1016/j.lfs.2022.120488
Bioengineered. 2022 Apr;13(4): 8349-8359

Nuclear receptor 4A1 (NR4A1) silencing protects hepatocyte against hypoxia-reperfusion injury in vitro by activating liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling.

Yu Zheng, Yingying Tao, Xiaobo Zhan, Qi Wu.

  The nuclear receptor 4A1 (NR4A1) is widely involved in the regulation of cell survival and is related to ischemic injury in several organs. This research examined the emerging role and mechanism of NR4A1 in hepatocyte ischemia-reperfusion injury (IRI). BRL-3A cells were subjected to hypoxia-reperfusion (H/R) to simulate an IRI model in vitro. The expression of NR4A1 and liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) pathway-related proteins (LKB1, AMPK, and ACC) was detected by western blotting or RT-qPCR under H/R condition after NR4A1 overexpression or silencing. Then, radicicol, an inhibitor of LKB1 pathway, was used to determine the role of NR4A1 in hepatocyte H/R injury by regulating LKB1. Under the help of CCK-8 assay, cell viability was assessed. The levels of ROS, MDA, and SOD were determined with corresponding kits to evaluate oxidative stress. Additionally, RT-qPCR was employed to analyze the releases of the inflammatory factors. Flow cytometry was applied to estimate the apoptosis and its related proteins, and autophagy-associated proteins were assayed by western blotting. Results indicated that NR4A1 was highly expressed, while proteins in LKB1/AMPK signaling was downregulated in BRL-3A cells exposed to H/R. The activation of LKB1/AMPK pathway could be negatively regulated by NR4A1. Moreover, NR4A1 depletion conspicuously promoted cell viability, inhibited oxidative stress as well as inflammation, and induced apoptosis and autophagy in H/R-stimulated BRL-3A cells, which were reversed after radicicol intervention. Collectively, NR4A1/LKB1/AMPK axis is a new protective pathway involved in hepatocyte IRI, shedding new insights into the improvement of hepatocyte IRI.

Keywords:  LKB1/AMPK; NR4A1; apoptosis; inflammation; ischemia-reperfusion injury; oxidative stress

DOI:  https://doi.org/10.1080/21655979.2022.2053804
Future Med Chem. 2022 Mar 24.

GANT61 elevates chemosensitivity to cisplatin through regulating the Hedgehog, AMPK and cAMP pathways in ovarian cancer.

Pengfeng Zhu, Li Wang, Peizhen Xu, Qingqing Tan, Yi Wang, Guannan Feng, Lei Yuan.

  Background: This study aimed to explore the effect of GANT61 on ovarian cancer (OC) chemosensitivity. Materials & methods: OC cells (Caov-3 and SKOV-3) were treated by GANT61 alone or combined with cisplatin/taxol. The mRNA sequencing was conducted, followed by rescue experiments. Results: GANT61 reduced OC cell viability in a dose-dependent manner and enhanced chemosensitivity to cisplatin but not to taxol. In total, 545 dysregulated genes were identified after the addition of GANT61 to cisplatin-treated OC cells, which were enriched in the AMPK, Hedgehog and cAMP pathways, then further validated by western blot. Furthermore, rescue experiments observed that AMPK pathway inhibitor and cAMP pathway inhibitor attenuated GANT61's chemosensitivity to cisplatin. Conclusion: GANT61 enforces OC chemosensitivity to cisplatin by regulating the Hedgehog, AMPK and cAMP pathways.

Keywords:  AMPK signaling pathway; GANT61; Hedgehog signaling pathway; cAMP signaling pathway; cisplatin; ovarian cancer

DOI:  https://doi.org/10.4155/fmc-2021-0310
Biosci Rep. 2022 Mar 24. pii: BSR20212584. [Epub ahead of print]

Microwave radiation induces neuronal autophagy through miR-30a-5p/AMPKα2 signal pathway.

Yanhui Hao, Wenchao Li, Hui Wang, Jing Zhang, Haoyu Wang, Ji Dong, Binwei Yao, Xinping Xu, Li Zhao, Ruiyun Peng.

  The potential health hazards of microwaves have attracted much more attention. Our previous study found that 2856 MHz microwave radiation damaged synaptic plasticity and activated autophagy in neurons. However, the mechanisms underlying microwave induced autophagy were still unclear. In the present study, we established neuronal damage models by exposing rat hippocampal neurons and rat adrenal pheochromocytoma (PC12) cell-derived neuron-like cells to 30 mW/cm2 microwaves, which resulted in miR-30a-5p ("miR-30a" for short) downregulation and autophagy activation in vivo and in vitro. Bioinformatics analysis was conducted, and Beclin1, Prkaa2, Irs1, Pik3r2, Rras2, Ddit4, Gabarapl2 and autophagy-related gene 12 (Atg12) were identified as potential downstream genes of miR-30a involved in regulating autophagy. Based on our previous findings that microwave radiation could lead to abnormal energy metabolism in neurons, Prkaa2, encoding adenosine 5'-monophosphate-activated protein kinase α2 (AMPKα2, an important catalytic subunit of energy sensor AMPK), was selected for further analysis. Dual-luciferase reporter assay results showed that Prkaa2 was a downstream gene of miR-30a. Moreover, microwave radiation increased the expression of AMPKα2 and the phosphorylation of AMPKα (Thr172) both in vivo and in vitro. The transfection of PC12 cells with miR-30a mimics increased miR-30a levels, reduced AMPKα2 expression, suppressed AMPKα (Thr172) phosphorylation, and inhibited autophagy occurrence in neuron-like cells. Importantly, miR-30a overexpression abolished microwave-activated autophagy and inhibited microwave-induced AMPKα2 upregulation and AMPKα (Thr172) phosphorylation. In conclusion, AMPKα2 was a newly identified downstream genes of miR-30a, microwave radiation promoted the occurrence of autophagy in neurons through the miR-30a/AMPKα2 pathway.

Keywords:  AMPK (5’-AMP activated kinase); Autophagy; Microwave radiation; Neuron; miR-30a-5p

DOI:  https://doi.org/10.1042/BSR20212584
Metab Brain Dis. 2022 Mar 22.

The C-glucosyl flavone isoorientin pretreatment attenuates the methylglyoxal-induced mitochondrial dysfunction in the human neuroblastoma SH-SY5Y cells: role for the AMPK-PI3K/Akt/Nrf2/γ-GCL/GSH axis.

Flávia Bittencourt Brasil, Fhelipe Jolner Souza de Almeida, Matheus Dargesso Luckachaki, Evandro Luiz Dall'Oglio, Marcos Roberto de Oliveira.

  The reactive dicarbonyl methylglyoxal (MG) behaves as a pro-oxidant agent, causing redox dysfunction and cell death by different mechanisms in mammalian cells. MG is also a mitochondrial toxicant, impairing the oxidative phosphorylation (OXPHOS) system and leading to bioenergetics and redox collapses. MG induces glycation and exerts an important role in neurodegenerative and cardiovascular diseases. Isoorientin (ISO), a C-glucosyl flavone found in Aspalathus linearis, Fagopyrum esculentum, and Passiflora edulis, among others, is an antioxidant and anti-inflammatory molecule. ISO is a potent inducer of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), the master modulator of the redox environment in mammals. We investigated here whether ISO would prevent the mitochondria-related redox and bioenergetics impairments induced by MG in the human neuroblastoma SH-SY5Y cells. The cells were administrated with ISO at 20 μM for 18 h prior to the exposure to MG at 500 μM for further 24 h. It was observed that ISO efficiently prevented the mitochondrial impairments caused by MG. ISO upregulated the activity of the enzyme γ-glutamate-cysteine ligase (γ-GCL), consequently stimulating the synthesis of glutathione (GSH). The inhibition of γ-GCL, adenosine monophosphate-activated protein kinase (AMPK), and phosphoinositide 3-kinase/Akt (PI3K/Akt) suppressed the beneficial effects induced by ISO on the MG-challenged cells. Moreover, silencing of Nrf2 blocked the ISO-dependent γ-GCL and GSH upregulation and the effects on the mitochondria of the MG-challenged cells. Then, ISO caused mitochondrial protection by an AMPK-PI3K/Akt/Nrf2/γ-GCL/GSH-dependent manner in MG-administrated SH-SY5Y cells.

Keywords:  Nrf2; glutathione; isoorientin; methylglyoxal; mitochondria; γ-glutamate-cyteine ligase

DOI:  https://doi.org/10.1007/s11011-022-00966-x
Antioxidants (Basel). 2022 Mar 18. pii: 580. [Epub ahead of print]11(3):

Combination Effects of Metformin and a Mixture of Lemon Balm and Dandelion on High-Fat Diet-Induced Metabolic Alterations in Mice.

Jae Young Choi, Tae-Woo Jang, Phil Hyun Song, Seong Hoon Choi, Sae-Kwang Ku, Chang-Hyun Song.

  Metformin, the first-line drug for type 2 diabetes mellitus (T2DM), has additional effects on improvements of nonalcoholic fatty liver disease (NAFLD); however, there are no treatments for both T2DM and NAFLD. Previous studies have shown hepatoprotective effects of a mixture of lemon balm and dandelion (LD) through its antioxidant and anti-steatosis properties. Thus, combination effects of metformin and LD were examined in a high-fat diet (HFD)-induced metabolic disease mouse model. The model received an oral administration of distilled water, monotherapies of metformin and LD, or a metformin combination with LD for 12 weeks. The HFD-induced weight gain and body fat deposition were reduced more by the combination than either monotherapy. Blood parameters for NAFLD (i.e., alanine aminotransferase and triglyceride), T2DM (i.e., glucose and insulin), and renal functions (i.e., blood urea nitrogen and creatinine) were reduced in the combination. The combination further enhanced hepatic antioxidant activities, and improved insulin resistance via the AMP-activated protein kinase and lipid metabolism pathways. Histopathological analyses revealed that the metformin combination ameliorated the hepatic hypertrophy/steatosis, pancreatic endocrine/exocrine alteration, fat tissue hypertrophy, and renal steatosis, more than either monotherapy. These results suggest that metformin combined with LD can be promising for preventing and treating metabolic diseases involving insulin resistance.

Keywords:  HFD; NAFLD; T2DM; combination; dandelion; dyslipidemia; kidney; lemon balm; metformin; obesity

DOI:  https://doi.org/10.3390/antiox11030580
Microorganisms. 2022 Feb 23. pii: 498. [Epub ahead of print]10(3):

Ca2+/Calmodulin-Dependent Protein Kinase II Inhibits Hepatitis B Virus Replication from cccDNA via AMPK Activation and AKT/mTOR Suppression.

Jumi Kim, Hyeonjoong Kwon, Fadia Kalsoom, Muhammad Azhar Sajjad, Hyun Woong Lee, Jin Hong Lim, Jaesung Jung, Yong-Joon Chwae, Sun Park, Ho-Joon Shin, Kyongmin Kim.

  Ca2+/calmodulin-dependent protein kinase II (CaMKII), which is involved in the calcium signaling pathway, is an important regulator of cancer cell proliferation, motility, growth, and metastasis. The effects of CaMKII on hepatitis B virus (HBV) replication have never been evaluated. Here, we found that phosphorylated, active CaMKII is reduced during HBV replication. Similar to other members of the AMPK/AKT/mTOR signaling pathway associated with HBV replication, CaMKII, which is associated with this pathway, was found to be a novel regulator of HBV replication. Overexpression of CaMKII reduced the expression of covalently closed circular DNA (cccDNA), HBV RNAs, and replicative intermediate (RI) DNAs while activating AMPK and inhibiting the AKT/mTOR signaling pathway. Findings in HBx-deficient mutant-transfected HepG2 cells showed that the CaMKII-mediated AMPK/AKT/mTOR signaling pathway was independent of HBx. Moreover, AMPK overexpression reduced HBV cccDNA, RNAs, and RI DNAs through CaMKII activation. Although AMPK acts downstream of CaMKII, AMPK overexpression altered CaMKII phosphorylation, suggesting that CaMKII and AMPK form a positive feedback loop. These results demonstrate that HBV replication suppresses CaMKII activity, and that CaMKII upregulation suppresses HBV replication from cccDNA via AMPK and the AKT/mTOR signaling pathway. Thus, activation or overexpression of CaMKII may be a new therapeutic target against HBV infection.

Keywords:  AKT/mTOR signaling pathway; AMPK; CaMKII; HBV replication; HBx; hepatitis B virus; hepatocellular carcinoma

DOI:  https://doi.org/10.3390/microorganisms10030498
Front Cell Dev Biol. 2022 ;10 871471

Editorial: Metabolism and Cell Adhesion in Cancer.

Tanja Nicole Hartmann.



Keywords:  AMPK; FAK; adhesion; integrin; mTOR; metabolism; migration; tumor microenvironment

DOI:  https://doi.org/10.3389/fcell.2022.871471
Toxicol In Vitro. 2022 Mar 20. pii: S0887-2333(22)00047-9. [Epub ahead of print] 105350

Puerarin attenuates LPS-induced inflammatory injury in gastric epithelial cells by repressing NLRP3 inflammasome-mediated apoptosis.

Zi-Tan Peng, Hui Liu.

  The NLRP3 inflammasome plays a crucial role in microbially induced gastric epithelial injury, but the underlying mechanisms remain unclear. Here, we aimed to assess the impacts of puerarin on LPS-induced inflammatory damage and the involvement of the AMPK/SIRT1/NLRP3 signaling pathways in this process in GES-1 cells. Cell viability and cytotoxicity were determined using CCK-8 and lactate dehydrogenase assay kits. Apoptosis was measured using annexin staining followed by flow cytometry. Cytokine levels were detected by ELISA, and protein expression was analyzed using western blotting. Protein overexpression was achieved by transfection with relevant pcDNA3.1 vectors, and protein knockdown was achieved by transfection with relevant siRNAs. Puerarin ameliorated LPS-induced cytotoxicity and apoptosis, while repressing LPS-stimulated NLRP3 inflammasome-mediated pyroptosis in GES-1 cells, as evidenced by significantly decreased expression of NLRP3, ASC, cleaved caspase-1, IL-1β and IL-18. NLRP3 knockdown efficiently repressed LPS-induced inflammatory injury in GES-1 cells. Puerarin activated the AMPK/SIRT1 pathway in LPS-treated GES-1 cells, and knockdown of both AMPK and SIRT1 reversed the protective effects of puerarin against LPS-induced inflammatory damage. AMPK overexpression strengthened, while AMPK knockdown weakened, the ability of puerarin to inhibit NLRP3-mediated inflammatory injury in LPS-treated GES-1 cells. Our findings suggest that puerarin may ameliorate LPS-induced inflammatory injury in GES-1 cells by activating the AMPK/SIRT1 signaling pathway and thereby repressing NLRP3 inflammasome-mediated apoptosis.

Keywords:  AMP-activated protein kinase; Gastric epithelial cells; NLRP3 inflammasome; Puerarin; Sirtuin 1

DOI:  https://doi.org/10.1016/j.tiv.2022.105350
Bioengineered. 2022 Apr;13(4): 8419-8431

Delivery of astragalus polysaccharide by ultrasound microbubbles attenuate doxorubicin-induced cardiomyopathy in rodent animals.

Yanjie Liu, Li Chen, Hao Wu, Hebin Zhang.

  The aim of this study was to investigate the cardioprotective effects and probable mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with astragalus polysaccharide (APS) on diabetic cardiomyopathy (DCM) model rats. The DCM rats with diabetes and cardiomyopathy were induced via chronic treatment of doxorubicin and then randomly divided into the (1) DCM model group; (2) APS microbubble group; (3) UTMDgroup; and (4) APS microbubbles combined with UTMD group. After 4-week intervention, the fasting blood glucose levels, body weight, %HbA1c level and glucose tolerance of DCM rats received combination therapy were significantly improved as compared with those of UTMD or saline-treated ones. Moreover, the heart/body weight ratio, and myocardial contractility were all improved after receiving combination therapy groups compared with others. In addition, significantly upregulated activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as significantly downregulated malondialdehyde (MDA) levels were all observed in the ones received combined treatment compared to others. Furthermore, the lipid accumulation and the expression levels of inflammatory factors were all significantly down-regulated in those ones received combination therapy compared with others (all P < 0.05). Further pathological analysis demonstrated that combination therapy effectively ameliorated fibrosis and myocardial morphological changes of DCM rats via activating the upregulation of AMPK and PPAR-γ signaling pathway, and inhibiting NF-κB activity in myocardial tissues of DCM rats. In conclusion, APS microbubbles combined with UTMD effectively protect the myocardial injury of DCM rats via activating AMPK signaling pathway to alleviate inflammation response, fibrosis and oxidative stress in myocardial tissues.

Keywords:  AMPK signaling pathway; Astragalus polysaccharide microbubbles; cardiomyopathy; fibrosis; inflammation; oxidative stress

DOI:  https://doi.org/10.1080/21655979.2022.2050481
Iran J Basic Med Sci. 2021 Nov;24(11): 1529-1537

Metformin synergistically increases the anticancer effects of lapatinib through induction of apoptosis and modulation of Akt/AMPK pathway in SK-BR3 breast cancer cell line.

Davood Neamati, Azam Khedri, Mohammad Aberomand, Ali-Asghar Hemmati, Maryam Mohammadzadeh, Kourosh Akbari Baghbani, Ghorban Mohammadzadeh.

  Objectives: Combination chemotherapy is a beneficial intervention for breast cancer, versus single therapy. We investigated the effect of Metformin (Met) on Lapatinib (Lap)-induced apoptosis in SK-BR3 cells.Materials and Methods: Toxic effect of Met and Lap on SK-BR3 cells was measured using MTT assay. Flow cytometry was used to measure the co-treatment effect of Met on lapatinib-induced apoptosis. The relative expression of Bax, Bcl2, and P21 was measured using a real-time PCR. The activity of caspase 3 and 9 was measured using an ELISA kit. The protein level of AMPK and Akt was determined using Western blot analysis.
Results: Metformin and lapatinib alone and combined form showed significant time- and dose-dependent toxic effects on SK-BR3 cell viability. The greatest synergistic inhibitory effect on the cell viability [combination index (CI) = 0.51] was remarkable at Met 100 mM combined with Lap 100 nM. The combination has a stronger apoptotic death (46%) versus lapatinib alone. The combination considerably increased the mRNA expression of Bax and P21, and caspase 3 and 9 activity, while, decreasing the mRNA expression of Bcl2. Additionally, the combination significantly up-regulated and down-regulated the protein levels of AMPK and Akt, respectively.
Conclusion: The metformin-lapatinib combination can induce more potent apoptotic death versus each compound individually. The combination may be suggested as a valuable therapeutic intervention in patients with breast cancer. However, additional in vivo studies are necessary to evaluate the clinical use of the combination for induction of apoptosis and its antitumor effects.

Keywords:  AMPK; Akt; Apoptosis; Drug synergism; Lapatinib; Metformin

DOI:  https://doi.org/10.22038/IJBMS.2021.58825.13069
BMC Genomics. 2022 Mar 19. 23(1): 219

Growth hormone receptor gene influences mitochondrial function and chicken lipid metabolism by AMPK-PGC1α-PPAR signaling pathway.

Minmin Yang, Bowen Hu, Donglei Sun, Changbin Zhao, Haohui Wei, Dajian Li, Zhiying Liao, Yongxia Zhao, Jinping Liang, Meiqing Shi, Qingbin Luo, Qinghua Nie, Xiquan Zhang, Dexiang Zhang, Hongmei Li.

  BACKGROUND: Adipose tissue is an important endocrine and energy-storage organ in organisms, and it plays a crucial role in the energy-metabolism balance. Previous studies have found that sex-linked dwarf (SLD) chickens generally have excessively high abdominal fat deposition during the growing period, which increases feeding costs. However, the underlying mechanism of this fat deposition during the growth of SLD chickens remains unknown.RESULTS: The Oil Red O staining showed that the lipid-droplet area of SLD chickens was larger than that of normal chickens in E15 and 14d. Consistently, TG content in the livers of SLD chickens was higher than that of normal chickens in E15 and 14d. Further, lower ΔΨm and lower ATP levels and higher MDA levels were observed in SLD chickens than normal chickens in both E15 and 14d. We also found that overexpression of GHR reduced the expression of genes related to lipid metabolism (AMPK, PGC1α, PPARγ, FAS, C/EBP) and oxidative phosphorylation (CYTB, CYTC, COX1, ATP), as well as reducing ΔΨm and ATP levels and increasing MDA levels. In addition, overexpression of GHR inhibited fat deposition in CPPAs, as measured by Oil Red O staining. On the contrary, knockdown of GHR had the opposite effects in vitro.
CONCLUSIONS: In summary, we demonstrate that GHR promotes mitochondrial function and inhibits lipid peroxidation as well as fat deposition in vivo and in vitro. Therefore, GHR is essential for maintaining the stability of lipid metabolism and regulating mitochondrial function in chicken.

Keywords:  GHR; Lipid metabolism; Mitochondrial function; Pre-adipocyte differentiation; Sex-linked dwarf chickens

DOI:  https://doi.org/10.1186/s12864-021-08268-9
Front Immunol. 2022 ;13 827146

SARS-CoV-2 Spike Protein 1 Activates Microvascular Endothelial Cells and Complement System Leading to Platelet Aggregation.

Luca Perico, Marina Morigi, Miriam Galbusera, Anna Pezzotta, Sara Gastoldi, Barbara Imberti, Annalisa Perna, Piero Ruggenenti, Roberta Donadelli, Ariela Benigni, Giuseppe Remuzzi.

  Microvascular thrombosis is associated with multiorgan failure and mortality in coronavirus disease 2019 (COVID-19). Although thrombotic complications may be ascribed to the ability of SARS-CoV-2 to infect and replicate in endothelial cells, it has been poorly investigated whether, in the complexity of viral infection in the human host, specific viral elements alone can induce endothelial damage. Detection of circulating spike protein in the sera of severe COVID-19 patients was evaluated by ELISA. In vitro experiments were performed on human microvascular endothelial cells from the derma and lung exposed to SARS-CoV-2-derived spike protein 1 (S1). The expression of adhesive molecules was studied by immunofluorescence and leukocyte adhesion and platelet aggregation were assessed under flow conditions. Angiotensin converting enzyme 2 (ACE2) and AMPK expression were investigated by Western Blot analysis. In addition, S1-treated endothelial cells were incubated with anti-ACE2 blocking antibody, AMPK agonist, or complement inhibitors. Our results show that significant levels of spike protein were found in the 30.4% of severe COVID-19 patients. In vitro, the activation of endothelial cells with S1 protein, via ACE2, impaired AMPK signalling, leading to robust leukocyte recruitment due to increased adhesive molecule expression and thrombomodulin loss. This S1-induced pro-inflammatory phenotype led to exuberant C3 and C5b-9 deposition on endothelial cells, along with C3a and C5a generation that further amplified S1-induced complement activation. Functional blockade of ACE2 or complement inhibition halted S1-induced platelet aggregates by limiting von Willebrand factor and P-selectin exocytosis and expression on endothelial cells. Overall, we demonstrate that SARS-CoV-2-derived S1 is sufficient in itself to propagate inflammatory and thrombogenic processes in the microvasculature, amplified by the complement system, recapitulating the thromboembolic complications of COVID-19.

Keywords:  COVID-19; SARS-CoV-2 spike protein 1; complement system; endothelial dysfunction; inflammation; thrombosis

DOI:  https://doi.org/10.3389/fimmu.2022.827146
Eur J Pharmacol. 2022 Mar 22. pii: S0014-2999(22)00174-1. [Epub ahead of print] 174913

Baicalin promotes the activation of brown and white adipose tissue through AMPK/PGC1α pathway.

Yanqing Zhang, Zhenzhen Zhang, Yiwei Zhang, Leiming Wu, Lu Gao, Rui Yao, Yanzhou Zhang.

  Obesity occurs when energy intake overtops energy expenditure. Promoting activation of brown adipose tissue (BAT) and white adipose tissue (WAT) has been proven a promising therapeutic strategy for obesity. Baicalin (BAI) has been shown to be protective for various animal models of cardiovascular diseases, such as pulmonary hypertension, atherosclerosis and myocardial hypertrophy. However, whether BAI could stimulate activation of BAT or browning of WAT remains unknown. Here we show that BAI limits weight gaining, ameliorates glucose tolerance, improves cold tolerance and promotes brown-like tissue formation in diet induced obesity mice model. BAI increases the mitochondrial copy number as judged by mtDNA detection. BAI also increases the expression of UCP1 and other classical browning-specific genes in BAT and WAT and cultured C3H10T1/2 adipocytes through a mechanism involving AMPK/PGC1α pathway. Collectively, our study established a role for BAI in regulating energy metabolism, which will provide new idea and theoretical basis for the treatment of obesity.

Keywords:  AMPK; Baicalin; Browning; PGC1α

DOI:  https://doi.org/10.1016/j.ejphar.2022.174913
Ecotoxicol Environ Saf. 2022 Mar 17. pii: S0147-6513(22)00202-0. [Epub ahead of print]235 113362

miR-296-5p promotes autophagy in mouse LS8 cells under excessive fluoride via AMPK/ULK1 pathways.

Yinyue Luo, Dongxin Da, Qingqing Weng, Shuran Yao, Hao Zhang, Xinxin Han, Ying Zhang.

  Numerous microRNAs participate in regulating the pathological process of autophagy. We have found miR-296-5p is one of the most significantly down-regulated microRNAs in a high concentration of sodium fluoride. However, it is not clear whether miR-296-5p augments autophagy in dental fluorosis. Our purpose is to explore the function of miR-296-5p in regulating autophagy of excessive fluoride development. Thus, the cell line of ameloblasts LS8 was exposed to a 1.5 mM dose of NaF and miR-296-5p-mimics, Real-time qPCR, CCK-8 assays, Fluorescence imaging and Western blot analysis were performed. Autophagy was observed. As our results indicated, miR-296-5p overexpression in mouse LS8 cells significantly accelerated autophagy. The autophagy inhibition effect of miR-296-5p underexpression was consistent with the effect of the AMPK inhibitor. And we found that the expression of LC3II was decreased via down-regulation of AMPK. The change of ULK1 by miR-296-5p may be accomplished through AMPK. Thus, miR-296-5p may improve the secretion of autophagic mediators by activating AMPK/ULK1 expression in fluorosis, suggesting that miR-296-5p, AMPK/ULK1 may be potential therapeutic targets under the higher fluoride stimulation.

Keywords:  AMPK/ULK1; Autophagy; Fluoride; MiR-296–5p

DOI:  https://doi.org/10.1016/j.ecoenv.2022.113362
Redox Biol. 2022 Mar 18. pii: S2213-2317(22)00060-X. [Epub ahead of print]52 102288

Empagliflozin attenuates cardiac microvascular ischemia/reperfusion through activating the AMPKα1/ULK1/FUNDC1/mitophagy pathway.

Chen Cai, Zhongzhou Guo, Xing Chang, Ziying Li, Feng Wu, Jing He, Tiantian Cao, Kangrong Wang, Nengxian Shi, Hao Zhou, Sam Toan, David Muid, Ying Tan.

  Mitophagy preserves microvascular structure and function during myocardial ischemia/reperfusion (I/R) injury. Empagliflozin, an anti-diabetes drug, may also protect mitochondria. We explored whether empagliflozin could reduce cardiac microvascular I/R injury by enhancing mitophagy. In mice, I/R injury induced luminal stenosis, microvessel wall damage, erythrocyte accumulation and perfusion defects in the myocardial microcirculation. Additionally, I/R triggered endothelial hyperpermeability and myocardial neutrophil infiltration, which upregulated adhesive factors and endothelin-1 but downregulated vascular endothelial cadherin and endothelial nitric oxide synthase in heart tissue. In vitro, I/R impaired the endothelial barrier function and integrity of cardiac microvascular endothelial cells (CMECs), while empagliflozin preserved CMEC homeostasis and thus maintained cardiac microvascular structure and function. I/R activated mitochondrial fission, oxidative stress and apoptotic signaling in CMECs, whereas empagliflozin normalized mitochondrial fission and fusion, neutralized supraphysiologic reactive oxygen species concentrations and suppressed mitochondrial apoptosis. Empagliflozin exerted these protective effects by activating FUNDC1-dependent mitophagy through the AMPKα1/ULK1 pathway. Both in vitro and in vivo, genetic ablation of AMPKα1 or FUNDC1 abolished the beneficial effects of empagliflozin on the myocardial microvasculature and CMECs. Taken together, the preservation of mitochondrial function through an activation of the AMPKα1/ULK1/FUNDC1/mitophagy pathway is the working mechanism of empagliflozin in attenuating cardiac microvascular I/R injury.

Keywords:  AMPKα1/ULK1 pathway; Cardiac microvascular I/R injury; Empagliflozin; FUNDC1-Dependent mitophagy

DOI:  https://doi.org/10.1016/j.redox.2022.102288
Sci Transl Med. 2022 Mar 23. 14(637): eabh3831

Hepatic IRF3 fuels dysglycemia in obesity through direct regulation of Ppp2r1b.

Suraj J Patel, Nan Liu, Sam Piaker, Anton Gulko, Maynara L Andrade, Frankie D Heyward, Tyler Sermersheim, Nufar Edinger, Harini Srinivasan, Margo P Emont, Gregory P Westcott, Jay Luther, Raymond T Chung, Shuai Yan, Manju Kumari, Reeby Thomas, Yann Deleye, André Tchernof, Phillip J White, Guido A Baselli, Marica Meroni, Dario F De Jesus, Rasheed Ahmad, Rohit N Kulkarni, Luca Valenti, Linus Tsai, Evan D Rosen.

Inflammation has profound but poorly understood effects on metabolism, especially in the context of obesity and nonalcoholic fatty liver disease (NAFLD). Here, we report that hepatic interferon regulatory factor 3 (IRF3) is a direct transcriptional regulator of glucose homeostasis through induction of Ppp2r1b, a component of serine/threonine phosphatase PP2A, and subsequent suppression of glucose production. Global ablation of IRF3 in mice on a high-fat diet protected against both steatosis and dysglycemia, whereas hepatocyte-specific loss of IRF3 affects only dysglycemia. Integration of the IRF3-dependent transcriptome and cistrome in mouse hepatocytes identifies Ppp2r1b as a direct IRF3 target responsible for mediating its metabolic actions on glucose homeostasis. IRF3-mediated induction of Ppp2r1b amplified PP2A activity, with subsequent dephosphorylation of AMPKα and AKT. Furthermore, suppression of hepatic Irf3 expression with antisense oligonucleotides reversed obesity-induced insulin resistance and restored glucose homeostasis in obese mice. Obese humans with NAFLD displayed enhanced activation of liver IRF3, with reversion after bariatric surgery. Hepatic PPP2R1B expression correlated with HgbA1C and was elevated in obese humans with impaired fasting glucose. We therefore identify the hepatic IRF3-PPP2R1B axis as a causal link between obesity-induced inflammation and dysglycemia and suggest an approach for limiting the metabolic dysfunction accompanying obesity-associated NAFLD.

DOI: https://doi.org/10.1126/scitranslmed.abh3831
Biomolecules. 2022 Feb 24. pii: 357. [Epub ahead of print]12(3):

Metformin and Cancer Hallmarks: Molecular Mechanisms in Thyroid, Prostate and Head and Neck Cancer Models.

Mirian Galliote Morale, Rodrigo Esaki Tamura, Ileana Gabriela Sanchez Rubio.

  Metformin is the most used drug for type 2 diabetes (T2DM). Its antitumor activity has been described by clinical studies showing reduced risk of cancer development in T2DM patients, as well as management of T2DM compared with those receiving other glucose-lowering drugs. Metformin has a plethora of molecular actions in cancer cells. This review focused on in vitro data on the action mechanisms of metformin on thyroid, prostate and head and neck cancer. AMPK activation regulating specific downstream targets is a constant antineoplastic activity in different types of cancer; however, AMPK-independent mechanisms are also relevant. In vitro evidence makes it clear that depending on the type of tumor, metformin has different actions; its effects may be modulated by different cell conditions (for instance, presence of HPV infection), or it may regulate tissue-specific factors, such as the Na+/I- symporter (NIS) and androgen receptors. The hallmarks of cancer are a set of functional features acquired by the cell during malignant development. In vitro studies show that metformin regulates almost all the hallmarks of cancer. Interestingly, metformin is one of these therapeutic agents with the potential to synergize with other chemotherapeutic agents, with low cost, low side effects and high positive consequences. Some questions are still challenging: Are metformin in vitro data able to translate from bench to bedside? Does metformin affect drug resistance? Can metformin be used as a generic anticancer drug for all types of tumors? Which are the specific actions of metformin on the peculiarities of each type of cancer? Several clinical trials are in progress or have been concluded for repurposing metformin as an anticancer drug. The continuous efforts in the field and future in vitro studies will be essential to corroborate clinical trials results and to elucidate the raised questions.

Keywords:  cancer; hallmarks; head and neck; in vitro; mechanisms; metformin; prostate; thyroid

DOI:  https://doi.org/10.3390/biom12030357