bims-amsmem 2022-07-10 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–07–10
thirty-two papers selected by
Dipsikha Biswas, Københavns Universitet

Hydroxycitric Acid Inhibits Chronic Myelogenous Leukemia Growth through Activation of AMPK and mTOR Pathway.
Aqueous extract of Scrophularia ningpoensis improves insulin sensitivity through AMPK-mediated inhibition of the NLRP3 inflammasome.
The effect of AMP kinase activation on differentiation and maturation of osteoblast cultured on titanium plate.
AMPK's double-faced role in advanced stages of prostate cancer.
Rhein attenuates angiotensin II-induced cardiac remodeling by modulating AMPK-FGF23 signaling.
The effect of gallic acid on memory and anxiety-like behaviors in rats with bile duct ligation-induced hepatic encephalopathy: Role of AMPK pathway.
Chitosan Oligosaccharide Inhibits the Synthesis of Milk Fat in Bovine Mammary Epithelial Cells through AMPK-Mediated Downstream Signaling Pathway.
Sestrin2 Regulates Beneficial β3-Adrenergic Receptor-Mediated Effects Observed in Inguinal White Adipose Tissue and Soleus Muscle.
Identification of the pathogenic effects of missense variants causing PRKAG2 cardiomyopathy.
Evaluating the impact of metformin targets on the risk of osteoarthritis: a Mendelian randomization study.
Brain pharmacokinetics and metabolism of the AMP-activated protein kinase selective inhibitor SBI-0206965, an investigational agent for the treatment of glioblastoma.
Metformin inhibits the development and metastasis of colorectal cancer.
Metformin suppresses pro-inflammatory cytokines in vitreous of diabetes patients and human retinal vascular endothelium.
The effect of chronic exposure to metformin in a new type-2 diabetic NONcNZO10/LtJ mouse model of stroke.
Development and Evaluation of Novel Metformin Derivative Metformin Threonate for Brain Ischemia Treatment.
Bryodulcosigenin attenuates bleomycin-induced pulmonary fibrosis via inhibiting AMPK-mediated mesenchymal epithelial transition and oxidative stress.
AMPK-ChREBP axis mediates de novo milk fatty acid synthesis promoted by glucose in the mammary gland of lactating goats.
Resveratrol, novel application by preconditioning to attenuate myocardial ischemia/reperfusion injury in mice through regulate AMPK pathway and autophagy level.
The SGLT2 inhibitor ertugliflozin modifies the signature of cardiac substrate metabolism and reduces cardiac mTOR-signaling, endoplasmic reticulum stress and apoptosis.
Heterophyllin B an Active Cyclopeptide Alleviates Dextran Sulfate Sodium-induced Colitis by Modulating Gut Microbiota and Repairing Intestinal Mucosal Barrier via AMPK Activation.
Salvianolic Acid B Alleviates Myocardial Ischemia Injury by Suppressing NLRP3 Inflammasome Activation via SIRT1-AMPK-PGC-1α Signaling Pathway.
The AMPK-SIRT1-FoxO1-NF-κB signaling pathway participates in Hesperetin-mediated neuroprotective effects against traumatic brain injury via the NLRP3 inflammasome.
Effects of N-Acetyl-L-Cysteine on Serum Indices and Hypothalamic AMPK-Related Gene Expression Under Chronic Heat Stress.
Cardiac contractility modulation ameliorates myocardial metabolic remodeling in a rabbit model of chronic heart failure through activation of AMPK and PPAR-α pathway.
Anti-oxidant effect of metformin through AMPK/SIRT1/PGC-1α/SIRT3- independent GPx1 expression in the heart of mice with endometriosis.
Identification of a Hydrogen-Sulfide-Releasing Isochroman-4-One Hybrid as a Cardioprotective Candidate for the Treatment of Cardiac Hypertrophy.
Investigation into the anti-inflammatory properties of metformin in intervertebral disc cells.
The potential therapeutic impact of metformin in glioblastoma multiforme.
Cardioprotective Effect of Gynostemma pentaphyllum against Streptozotocin Induced Cardiac Toxicity in Rats via Alteration of AMPK/Nrf2/HO-1 Pathway.
The effects of Formoterol in preventing adipogenesis and obesity are mediated by PPARγ/C/EBPα axis and AMPK/PGC-1α pathway.
Long noncoding RNA TRG-AS1 protects against glucocorticoid-induced osteoporosis in a rat model by regulating miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.
Methyl eugenol protects the kidney from oxidative damage in mice by blocking the Nrf2 nuclear export signal through activation of the AMPK/GSK3β axis.

Nutrients. 2022 Jun 27. pii: 2669. [Epub ahead of print]14(13):

Hydroxycitric Acid Inhibits Chronic Myelogenous Leukemia Growth through Activation of AMPK and mTOR Pathway.

Doriana Verrelli, Luca Dallera, Massimo Stendardo, Silvia Monzani, Sebastiano Pasqualato, Marco Giorgio, Rani Pallavi.

  Metabolic regulation of cancer cell growth via AMP-activated protein kinase (AMPK) activation is a widely studied strategy for cancer treatment, including leukemias. Recent notions that naturally occurring compounds might have AMPK activity led to the search for nutraceuticals with potential AMPK-stimulating activity. We found that hydroxycitric acid (HCA), a natural, safe bioactive from the plant Garcinia gummi-gutta (cambogia), has potent AMPK activity in chronic myelogenous leukemia (CML) cell line K562. HCA is a known competitive inhibitor of ATP citrate lyase (ACLY) and is widely used as a weight loss inducer. We found that HCA was able to inhibit the growth of K562 cells in in vitro and in vivo xenograft models. At the mechanistic level, we identified a direct interaction between AMPK and ACLY that seems to be sensitive to HCA treatment. Additionally, HCA treatment resulted in the co-activation of AMPK and the mammalian target of rapamycin (mTOR) pathways. Moreover, we found an enhanced unfolded protein response as observed by activation of the eIF2α/ATF4 pathway that could explain the induction of cell cycle arrest at the G2/M phase and DNA fragmentation upon HCA treatment in K562 cells. Overall, these findings suggest HCA as a nutraceutical approach for the treatment of CMLs.

Keywords:  AMPK; CML; hydroxycitric acid; nutraceuticals

DOI:  https://doi.org/10.3390/nu14132669
Phytomedicine. 2022 Jun 28. pii: S0944-7113(22)00387-7. [Epub ahead of print]104 154308

Aqueous extract of Scrophularia ningpoensis improves insulin sensitivity through AMPK-mediated inhibition of the NLRP3 inflammasome.

Shan Yan, Wei Lu, Jun Zhou, Xu Guo, Juyi Li, Hongbo Cheng, Xiaoyan Zhu, Yan Zhao, Mingzhu Duan, Hongxu Yang, Yonghong Zhang, Qibin Wang, Li Chen, Tao Zheng.

   BACKGROUND: Scrophularia ningpoensis Hemsl. is a commonly used medicinal plant in China for the treatment of diabetes mellitus (DM), but its mechanism of action remains poorly described. Type 2 diabetes mellitus (T2DM) accounts for > 90% of all DM cases and is characterized by insulin resistance.
PURPOSE: The aim of this study was to investigate whether the insulin sensitivity can be improved by treatment with aqueous extract of S. ningpoensis (AESN) and further explore its mechanism(s) of activity.
METHODS: Primary mouse hepatocytes and human HepG2 hepatocytes were used to investigate the effects of AESN on cell viability, AMP-activated protein kinase (AMPK) activation and glucose output under normal culture conditions. To mimic hyperglycemia and insulin resistance in vitro, hepatocytes were exposed to high glucose (HG), and the influences of AESN on AMPK phosphorylation, NLRP3 inflammation activation, insulin signaling, lipid accumulation and glucose output were investigated. Increasing doses of AESN (50, 100 and 200 mg/kg/day) were administered by gavage to db/db mice for 8 weeks, and then biochemical analysis and histopathological examinations were performed.
RESULTS: AESN significantly activated AMPK and inhibited glucose output in hepatocytes, but did not impact cell viability under normal culture conditions. Moreover, in HG-treated hepatocytes, AESN protected against aberrant AMPK activity, NLRP3 inflammasome activation, insulin signaling, and lipid accumulation. AMPK inhibition abolished the regulatory effects of AESN on the NLRP3 inflammasome, insulin signaling, lipid accumulation, and glucose output of hepatocytes following HG exposure. Furthermore, AESN administration reduced blood glucose and serum insulin levels, improved lipid profiles and insulin resistance, and corrected the aberrant AMPK activity and NLRP3 inflammasome activation in liver tissues.
CONCLUSION: AESN improves insulin sensitivity via AMPK-mediated NLRP3 inflammasome inhibition.

Keywords:  AMP-activated protein kinase; Diabetes mellitus; Insulin sensitivity; NLRP3inflammasome; Scrophularia ningpoensis Hemsl.

DOI:  https://doi.org/10.1016/j.phymed.2022.154308
J Dent Sci. 2022 Jul;17(3): 1225-1231

The effect of AMP kinase activation on differentiation and maturation of osteoblast cultured on titanium plate.

Phanthavong Vansana, Kae Kakura, Yusuke Taniguchi, Kei Egashira, Etsuko Matsuzaki, Takashi Tsutsumi, Hirofumi Kido.

   Background/purpose: 5' Adenosine monophosphate-activated protein kinase (AMPK) is known as an enzyme that maintains intracellular homeostasis and has various biological activity. The purpose of this study is evaluation effect of AMPK activation on implant prognosis.
Materials & methods: MC3T3-E1 osteoblast-like cells were cultured on titanium using a 24-well plate. The experimental group was divided into the following 3 groups: (1) the normal culture group (control group), (2) the osteogenic induction group, and (3) the osteogenic induction + AMPK activation group. The cell counts were measured; real-time PCR was used to assess the expression of ALP and Osterix as osteogenic related genes at Day 0,7,14 and 21 after experiments. Additionally, ALP activity and calcification were assessed.
Results: The results of the real-time PCR assessments revealed that the expression of ALP, which is a marker for the initial stages of calcification, was significantly increased by AMPK activation compared to the normal culture or osteogenic induction. A significant increase was also observed in the expression of Osterix, which is a marker for the later stages of calcification. Because significant increases were observed in ALP activity and calcification potential, this suggested that AMPK activation could elicit an increase in osteoblast calcification potential.
Conclusion: AMPK activation promotes implant peripheral osteoblast differentiation and maturation and enhances calcification. Our results suggest that AMPK activation may help to maintain implant stability.

Keywords:  5′ adenosine monophosphate-activated protein kinase; Acadesine/AICA riboside; Dental implant; Osteoblast

DOI:  https://doi.org/10.1016/j.jds.2021.12.003
Clin Transl Oncol. 2022 Jul 04.

AMPK's double-faced role in advanced stages of prostate cancer.

Faeze Gharibpoor, Sara Kamali Zonouzi, Sepideh Razi, Nima Rezaei.

  Prostate cancer (PCa) is the second leading cause of cancer deaths in men. Unfortunately, a very limited number of drugs are available for the relapsed and advanced stages of PCa, adding only a few months to survival; therefore, it is vital to develop new drugs. 5´ AMP-activated protein kinase (AMPK) is a master regulator of cell metabolism. It plays a significant role in the metabolism of PCa; hence, it can serve well as a treatment option for the advanced stages of PCa. However, whether this pathway contributes to cancer cell survival or death remains unknown. The present study reviews the possible pathways by which AMPK plays role in the advanced stages of PCa, drug resistance, and metastasis: (1) AMPK has a contradictory role in promoting glycolysis and the Warburg effect which are correlated with cancer stem cells (CSCs) survival and advanced PCa. It exerts its effect by interacting with hypoxia-induced factor 1 (HIF1) α, pyruvate kinase 2 (PKM2), glucose transporter (GLUT) 1 and pyruvate dehydrogenase complex (PDHC), which are key regulators of glycolysis; however, whether it promotes or discourage glycolysis is not conclusive. It can also exert an anti-CSC effect by negative regulation of NANOG and epithelial-mesenchymal transition (EMT) transcription factors, which are the major drivers of CSC maintenance; (2) the regulatory effect of AMPK on autophagy is also noticeable. Androgen receptors' expression increases AMPK activation through Calcium/calmodulin-dependent protein kinase 2 (CaMKK2) and induces autophagy. In addition, AMPK itself increases autophagy by downregulating the mammalian target of rapamycin complex (mTORC). However, whether increased autophagy inhibits or promotes cell death and drug resistance is contradictory. This study reveals that there are numerous pathways other than cell metabolism by which AMPK exerts its effects in the advanced stages of PCa, making it a priceless treatment target. Finally, we mention some drugs developed to treat the advanced stages of PCa by acting on AMPK.

Keywords:  AMPK; Autophagy; Cancer stem cell; Prostate cancer; Warburg

DOI:  https://doi.org/10.1007/s12094-022-02874-z
J Transl Med. 2022 Jul 06. 20(1): 305

Rhein attenuates angiotensin II-induced cardiac remodeling by modulating AMPK-FGF23 signaling.

Wei Lu, Hongqiao Zhu, Jiawen Wu, Sheng Liao, Guobing Cheng, Xiaoyang Li.

   BACKGROUND: Increasing evidence indicates that myocardial oxidative injury plays a crucial role in the pathophysiology of cardiac hypertrophy (CH) and heart failure (HF). The active component of rhubarb, rhein exerts significant actions on oxidative stress and inflammation. Nonetheless, its role in cardiac remodeling remains unclear.
METHODS: CH was induced by angiotensin II (Ang II, 1.4 mg/kg/d for 4 weeks) in male C57BL/6 J mice. Then, rhein (50 and 100 mg/kg) was injected intraperitoneally for 28 days. CH, fibrosis, oxidative stress, and cardiac function in the mice were examined. In vitro, neonatal rat cardiomyocytes (CMs) and cardiac fibroblasts (CFs) pre-treated with rhein (5 and 25 μM) were challenged with Ang II. We performed RNA sequencing to determine the mechanistic role of rhein in the heart.
RESULTS: Rhein significantly suppressed Ang II-induced CH, fibrosis, and reactive oxygen species production and improved cardiac systolic dysfunction in vivo. In vitro, rhein significantly attenuated Ang II-induced CM hypertrophy and CF collagen expression. In addition, rhein obviously alleviated the increased production of superoxide induced by Ang II. Mechanistically, rhein inhibited FGF23 expression significantly. Furthermore, FGF23 overexpression abolished the protective effects of rhein on CMs, CFs, and cardiac remodeling. Rhein reduced FGF23 expression, mostly through the activation of AMPK (AMP-activated protein kinase). AMPK activity inhibition suppressed Ang II-induced CM hypertrophy and CF phenotypic transformation.
CONCLUSION: Rhein inhibited Ang II-induced CH, fibrosis, and oxidative stress during cardiac remodeling through the AMPK-FGF23 axis. These findings suggested that rhein could serve as a potential therapy in cardiac remodeling and HF.

Keywords:  AMPK; Cardiac remodeling; FGF23; ROS; Rhein

DOI:  https://doi.org/10.1186/s12967-022-03482-9
Avicenna J Phytomed. 2022 Jul-Aug;12(4):12(4): 425-438

The effect of gallic acid on memory and anxiety-like behaviors in rats with bile duct ligation-induced hepatic encephalopathy: Role of AMPK pathway.

Leila Jafaripour, Khadijeh Esmaeilpour, Marzieh Maneshian, Hamideh Bashiri, Mohammad Amin Rajizadeh, Hassan Ahmadvand, Majid Asadi-Shekaari.

   Objective: Hepatic encephalopathy (HE) is a serious neurological syndrome which is caused by acute and chronic liver diseases. In this study, the effect of gallic acid (GA) as an activator of AMP-activated protein kinase (AMPK) on memory and anxiety-like behaviors in rats with HE caused by bile duct ligation (BDL) was investigated.
Materials and Methods: The rats were randomly divided into the following eight groups (n=7): sham; BDL; BDL+GA 20 mg/kg; BDL+GA 30 mg/kg; sham+dorsomorphin or compound C (CC) (as AMPK inhibitors); BDL+CC; BDL+GA 20 mg/kg+CC; and BDL+GA 30 mg/kg+CC. The rats received GA once daily by gavage for four weeks, and dorsomorphin 6.2 µg per rat was administered on a daily basis via bilateral intraventricular injection for four weeks. Behavioral tests including novel object recognition (NOR), open field and Morris water maze (MWM) were used to evaluate anxiety and memory in the rats.
Results: Examining some parameters of NOR and MWM tests showed that memory performance was significantly reduced in the BDL versus the sham group, and in the BDL+CC versus the sham+CC group (p<0.05). GA intake improved memory in the GA-receiving groups compared with the BDL and BDL+CC groups (p<0.05). Examining some parameters of open field test showed that anxiety was significantly increased in the BDL versus the sham group, and the BDL+CC versus the sham+CC group (p<0.05). GA intake reduced anxiety in GA-receiving groups compared with the BDL+BDL+CC group (p<0.05).
Conclusion: GA was effective in improving cognitive and anxiety-like behaviors through activating AMPK.

Keywords:  AMPK activation; Bile duct ligation; Gallic acid; Hepatic encephalopathy; Memory

DOI:  https://doi.org/10.22038/AJP.2022.19720
Animals (Basel). 2022 Jun 30. pii: 1692. [Epub ahead of print]12(13):

Chitosan Oligosaccharide Inhibits the Synthesis of Milk Fat in Bovine Mammary Epithelial Cells through AMPK-Mediated Downstream Signaling Pathway.

Jing Fan, Jiayi Chen, Haochen Wu, Xin Lu, Xibi Fang, Fuquan Yin, Zhihui Zhao, Ping Jiang, Haibin Yu.

  Chitosan oligosaccharide (COS) is a variety of oligosaccharides, and it is also the only abundant basic amino oligosaccharide in natural polysaccharides. Chitosan oligosaccharide is a low molecular weight product of chitosan after enzymatic degradation. It has many biological effects, such as lipid-lowering, antioxidant and immune regulation. Previous studies have shown that chitosan oligosaccharide has a certain effect on fat synthesis, but the effect of chitosan oligosaccharide on milk fat synthesis of bovine mammary epithelial cells (BMECs) has not been studied. Therefore, this study aimed to investigate chitosan oligosaccharide's effect on milk fat synthesis in bovine mammary epithelial cells and explore the underlying mechanism. We treated bovine mammary epithelial cells with different concentrations of chitosan oligosaccharide (0, 100, 150, 200, 400 and 800 μg/mL) for 24 h, 36 h and 48 h respectively. To assess the effect of chitosan oligosaccharide on bovine mammary epithelial cells and determine the concentration and time for chitosan oligosaccharide treatment on cells, several in vitro cellular experiments, including on cell viability, cycle and proliferation were carried out. The results highlighted that chitosan oligosaccharide (100, 150 μg/mL) significantly promoted cell viability, cycle and proliferation, increased intracellular cholesterol content, and reduced intracellular triglyceride and non-esterified fatty acids content. Under the stimulation of chitosan oligosaccharide, the expression of genes downstream of Phosphorylated AMP-activated protein kinase (P-AMPK) and AMP-activated protein kinase (AMPK) signaling pathway changed, increasing the expression of peroxisome proliferator-activated receptor alpha (PPARα) and hormone-sensitive lipase (HSL), but the expression of sterol regulatory element-binding protein 1c (SREBP1) and its downstream target gene stearoyl-CoA desaturase (SCD1) decreased. In conclusion, these results suggest that chitosan oligosaccharide may inhibit milk fat synthesis in bovine mammary epithelial cells by activating the AMP-activated protein kinase signaling pathway, promoting the oxidative decomposition of fatty acids and inhibiting fatty acid synthesis.

Keywords:  AMPK signalling pathway; bovine mammary epithelial cells; chitosan oligosaccharide; milk fat synthesis

DOI:  https://doi.org/10.3390/ani12131692
Endocrinol Metab (Seoul). 2022 Jun;37(3): 552-557

Sestrin2 Regulates Beneficial β3-Adrenergic Receptor-Mediated Effects Observed in Inguinal White Adipose Tissue and Soleus Muscle.

Min Jeong Park, Joo Won Kim, Eun Roh, Kyung Mook Choi, Sei Hyun Baik, Hwan-Jin Hwang, Hye Jin Yoo.

  Sestrin2, a well-known adenosine monophosphate-activated protein kinase (AMPK) regulator, plays a protective role against metabolic stress. The β3-adrenergic receptor (β3AR) induces fat browning and inhibits muscle atrophy in an AMPK-dependent manner. However, no prior research has examined the relationship of sestrin2 with β3AR in body composition changes. In this study, CL 316,243 (CL), a β3AR agonist, was administered to wild-type and sestrin2-knockout (KO) mice for 2 weeks, and fat and muscle tissues were harvested. CL induced AMPK phosphorylation, expression of brown-fat markers, and mitochondrial biogenesis, which resulted in the reduction of lipid droplet size in inguinal white adipose tissue (iWAT). These effects were not observed in sestrin2-KO mice. In CL-treated soleus muscle, sestrin2-KO was related to decreased myogenic gene expression and increased levels of muscle atrophy-related molecules. Our results suggest that sestrin2 is associated with beneficial β3AR-mediated changes in body composition, especially in iWAT and in the soleus.

Keywords:  Adipose tissue, brown; Adrenergic beta-3 receptor agonists; Muscle development; Muscular atrophy; Sestrin2 protein, mouse

DOI:  https://doi.org/10.3803/EnM.2022.1421
Arch Biochem Biophys. 2022 Jul 01. pii: S0003-9861(22)00224-7. [Epub ahead of print]727 109340

Identification of the pathogenic effects of missense variants causing PRKAG2 cardiomyopathy.

Evrim Komurcu-Bayrak, Muhammed Abdulvahid Kalkan, Neslihan Coban, Bilge Ozsait-Selcuk, Fatih Bayrak.

   BACKGROUND: Pathogenic missense variants in PRKAG2, the gene for the gamma 2 regulatory subunit of adenosine monophosphate-activated protein kinase (AMPK), cause severe progressive cardiac disease and sudden cardiac death, named PRKAG2 cardiomyopathy. In our previous study, we reported a E506K variant in the PRKAG2 gene that was associated with this disease. This study aimed to functionally characterize the three missense variants (E506K, E506Q, and R531G) of PRKAG2 and determine the possible effects on AMPK activity.
METHODS: The proband was clinically monitored for eight years. To investigate the functional effects of three missense variants of PRKAG2, in vitro mutagenesis experiments using HEK293 cells with wild and mutant transcripts and proteins were comparatively analyzed using quantitative RT-PCR, immunofluorescence staining, and enzyme-linked immunosorbent assay.
RESULTS: In the long-term follow-up, the proband was deceased due to progressive heart failure. In the in vitro experimental studies, PRKAG2 was overexpressed after 48 h of transfection in three mutated cells, after which the expression levels of PRKAG2 were regressed to the level of wild-type cells in 3-weeks stably transformed cells, except for the cells with E506K variant. E506K, E506Q, and R531G variants had caused a reduction in the AMPK activity and resulted in the formation of cytoplasmic glycogen deposits.
CONCLUSION: Three missense variants that alter AMPK activity affect a residue in the CBS4 domain associated with ATP/AMP-binding. Detailed information on the influence of PRKAG2 pathogenic variants on AMPK activity would be helpful to improve the treatment and management of patients with metabolic cardiomyopathy.

Keywords:  AMPK; Cell culture; In vitro mutagenesis; Missense variant; PRKAG2 cardiomyopathy

DOI:  https://doi.org/10.1016/j.abb.2022.109340
Osteoarthritis Cartilage. 2022 Jul 05. pii: S1063-4584(22)00774-9. [Epub ahead of print]

Evaluating the impact of metformin targets on the risk of osteoarthritis: a Mendelian randomization study.

Yan Zhang, Delong Li, Zhaohua Zhu, Shibo Chen, Ming Lu, Peihua Cao, Tianyu Chen, Shengfa Li, Song Xue, Yujie Zhang, Jianwei Zhu, Guangfeng Ruan, Changhai Ding.

   OBJECTIVE: To provide some causal evidence concerning the effects of metformin on osteoarthritis (OA) using two metformin targets, namely AMP-activated protein kinase (AMPK) and growth differentiation factor 15 (GDF-15) as metformin proxies.
METHODS: This is a 2-sample Mendelian randomization design. We constructed 44 AMPK-related variants genetically predicted in HbA1c (%) as instruments for AMPK and five variants strongly predicted GDF-15 as instruments for GDF-15. Summary-level data for three OA phenotypes, including OA at any site, knee OA, and hip OA were obtained from the largest genome-wide meta-analysis across the UK Biobank and arcOGEN with 455,211 Europeans. Main analyses were conducted using the inverse-variance weighted method. Weighted median and MR-Egger were conducted as sensitivity analyses to assess the robustness of our results.
RESULTS: Genetically predicted AMPK were negatively associated with OA at any site (OR: 0.60; 95% CI: 0.43-0.83) and hip OA (OR: 0.42; 95% CI: 0.22-0.80), but with not knee OA (OR: 0.85; 95% CI: 0.49-1.50). Higher levels of genetically predicted GDF-15 reduced the risk of hip OA (OR: 0.95; 95% CI: 0.90-0.99), but not OA at any site (OR: 1.00; 95% CI: 0.98-1.02) and knee OA (OR: 1.02; 95% CI: 0.98-1.07).
CONCLUSION: This study indicates that AMPK and GDF-15 can be potential therapeutic targets for OA, especially for hip OA, and metformin would be repurposed for OA therapy which needs to be verified in randomized controlled trials.

Keywords:  AMPK; GDF-15; Mendelian randomization; metformin; osteoarthritis

DOI:  https://doi.org/10.1016/j.joca.2022.06.010
Invest New Drugs. 2022 Jul 08.

Brain pharmacokinetics and metabolism of the AMP-activated protein kinase selective inhibitor SBI-0206965, an investigational agent for the treatment of glioblastoma.

Janki M Desai, Aniruddha S Karve, Gary A Gudelsky, Mruniya V Gawali, William Seibel, Larry Sallans, Biplab DasGupta, Pankaj B Desai.

   PURPOSE: Emerging evidence suggests that 5' Adenosine Monophosphate-Activated Protein Kinase (AMPK), a key regulator of cellular bioenergetics, is a novel target for the treatment of glioblastoma (GBM), a lethal brain tumor. SBI-0206965, an aminopyrimidine derivative, is a potent AMPK inhibitor being investigated for the treatment of GBM. Here we characterized the systemic and brain pharmacokinetics (PK) and hepatic metabolism of SBI-0206965.
METHODS: We performed intracerebral microdialysis to determine brain partitioning of SBI-0206965 in jugular vein cannulated rats. We assessed systemic PK of SBI-0206965 in rats and C57BL/6 mice following oral administration. Employing human, mouse, and rat liver microsomes we characterized the metabolism of SBI-0206965.
RESULTS: SBI-0206965 is quickly absorbed, achieving plasma and brain extracellular fluid (ECF) peak levels within 0.25 - 0.65 h. Based on the ratio of Cmax and AUC in brain ECF to plasma (corrected for protein binding), brain partitioning is ~ 0.6-0.9 in rats. However, the compound has a short elimination half-life (1-2 h) and low relative oral bioavailability (~ 0.15). The estimated in-vitro hepatic intrinsic clearance of SBI-0206965 in mouse, rat and human was 325, 76 and 68 mL/min/kg, respectively. SBI-0206965 metabolites included desmethylated products, and the metabolism was strongly inhibited by ketoconazole, a CYP3A inhibitor.
CONCLUSION: SBI-0206965 has adequate brain permeability but low relative oral bioavailability which may be due to rapid hepatic metabolism, likely catalyzed by CYP3A enzymes. Our observations will facilitate further development of SBI-0206965, and/or other structurally related molecules, for the treatment of GBM and other brain tumors.

Keywords:  5’ Adenosine Monophosphate-Activated Protein Kinase; Brain partitioning; Glioblastoma; In-vitro metabolism

DOI:  https://doi.org/10.1007/s10637-022-01278-8
Med Oncol. 2022 Jul 02. 39(9): 136

Metformin inhibits the development and metastasis of colorectal cancer.

Kiyoaki Sugiura, Koji Okabayashi, Ryo Seishima, Takashi Ishida, Kohei Shigeta, Masashi Tsuruta, Hirotoshi Hasegawa, Yuko Kitagawa.

  Metformin is a commonly used drug for the treatment of diabetes. Accumulating evidence suggests that it exerts anti-cancer effects in many cancers, including colorectal cancer. However, the underlying molecular mechanisms of colorectal cancer metastasis remain unclear. Colorectal cancer cell lines were treated with metformin, and cell proliferation, invasion, and migration were analyzed in vitro. The relationship between metformin and the AMPK-mTOR axis was assessed by Western blot analysis and transfection with small interfering RNA. A colorectal cancer xenograft mouse model was used to observe the effects of metformin on liver metastasis. Immunohistochemical analysis was performed on liver metastatic tumors. In in vitro experiments, metformin significantly inhibited the proliferation, migration, and invasion only in HCT116 and SW837 cells, but not in HCT8 and Lovo cells. Only in HCT116 and SW837, a change in AMPK-mTOR expression was observed in a dose-dependent manner. In colorectal cancer xenograft mice, the liver metastatic rate (10% vs. 50%, p = 0.05) and the number of liver metastatic nodules (0.1/body vs. 1.2/body, p = 0.04) were significantly lower in the metformin group. Tumor proliferation and EMT were decreased and apoptosis was promoted only in metastatic liver tumors of mice treated with metformin. The molecular mechanism of the anti-cancer effects of metformin involves repression of mTOR pathways via AMPK activation. Moreover, the differences in metformin sensitivity depend on the response of the AMPK-mTOR pathway to metformin. Our study provides a theoretical basis for the anti-metastatic treatment of colorectal cancer using metformin.

Keywords:  AMP-activated protein kinase; Colorectal cancer; Mammalian target of rapamycin; Metastasis; Metformin

DOI:  https://doi.org/10.1007/s12032-022-01722-y
PLoS One. 2022 ;17(7): e0268451

Metformin suppresses pro-inflammatory cytokines in vitreous of diabetes patients and human retinal vascular endothelium.

Yue Li, Shawn Gappy, Xiuli Liu, Therese Sassalos, Tongrong Zhou, Andrew Hsu, Alice Zhang, Paul A Edwards, Hua Gao, Xiaoxi Qiao.

Metformin is a traditional anti-hyperglycemic medication that has recently been shown to benefit vascular complications of diabetes via an anti-inflammatory mechanism other than glycemic control. This study aims to test the hypothesis that metformin suppresses diabetic retinopathy (DR) associated intraocular inflammation. Human vitreous from control and proliferative diabetic retinopathy (PDR) patients with or without long-term metformin treatment (> 5 years) were collected for multiple inflammatory cytokines measurements with a cytokine array kit. The vast majority of the measurable cytokines in PDR vitreous has a lower level in metformin group than non-metformin group. Although the p values are not significant due to a relatively small sample size and large deviations, the 95% confidence interval (CI) for the mean difference between the two groups shows some difference in the true values should not be neglected. Using quantitative ELISA, soluble intercellular adhesion molecule -1 (ICAM-1) and monocyte chemoattractant protein -1 (MCP-1) presented with significantly lower concentrations in metformin group versus non-metformin group. Metformin group also has significantly less up-regulated cytokines and diminished positive correlations among the cytokines when compared to non-metformin group. Possible role of AMP-activated protein kinase (AMPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in metformin's anti-inflammatory effects were studied in human retinal vascular endothelial cells (hRVECs) cultured in normal glucose (NG) and high glucose (HG) conditions. Metformin inhibited HG-induced ICAM-1, IL-8, and MCP-1 via AMPK activation, whereas pharmacological AMPK inhibition had no effect on its inhibition of NF-κB p65, sICAM-1, and tumor necrosis factor-α (TNF-α). Metformin-induced suppression of the inflammatory cytokines could also be mediated through its direct inhibition of NF-κB, independent of AMPK pathway. This is a proof-of-concept study that found metformin treatment was associated with reduced inflammatory responses in vitreous of diabetes patients and retinal vascular endothelial cells, supporting the rationale for using metformin to treat DR at an early stage.

DOI: https://doi.org/10.1371/journal.pone.0268451
Pharmacol Rep. 2022 Jul 06.

The effect of chronic exposure to metformin in a new type-2 diabetic NONcNZO10/LtJ mouse model of stroke.

Rashmi Kumari, Lisa Willing, Scot R Kimball, Ian A Simpson.

   BACKGROUND: Diabetes is an independent risk factor of stroke and previous studies have confirmed that diabetic patients and animals experience poorer clinical outcomes following stroke. In this study, we aim to determine the effect of chronic exposure of the first-line antidiabetic agent, metformin, to restore euglycemia and to impact brain cell death following stroke in a new type-2 diabetes, NONcNZO10/LtJ (RCS-10) mouse model of stroke.
METHODS: Male RCS-10 mice received a moderate (11%) fat diet post-weaning, at 4 weeks of age, and became diabetic by 12-14 weeks, thus resembling human maturity-onset diabetes. The mice received either metformin or vehicle for 4 weeks before undergoing a hypoxic/ischemic (HI) insult. Blood samples were collected pre-, post-treatment, and post HI for glucose and lipid measurements, and brains were analyzed for infarct size, glial activation, neuronal cell death, and metformin-mediated adenosine monophosphate-activated protein kinase (AMPK) signaling at 48 h post HI.
RESULTS: Pretreatment with metformin maintained euglycemia for 4 weeks but did not change body weight or lipid profile. Metformin treatment significantly enhanced the microglial Bfl-1 mRNA expression and showed a non-significant increase in GFAP mRNA, however, GFAP protein levels were reduced. Metformin treatment slightly increased neuronal NeuN and MAP-2 protein levels and significantly reduced overall mortality post HI but did not elicit any significant change in infarct size.
CONCLUSION: The study suggests that the prolonged effect of metformin-induced euglycemia promoted the microglial activation, reduced neuronal cell death, and improved the overall survival following stroke, without any change in infarct size.

Keywords:  Metformin; Neuroprotection; RCS-10 diabetic mouse; Stroke

DOI:  https://doi.org/10.1007/s43440-022-00382-z
Front Pharmacol. 2022 ;13 879690

Development and Evaluation of Novel Metformin Derivative Metformin Threonate for Brain Ischemia Treatment.

Gufang Zhang, Shuangshuang Chen, Jia Jia, Chun Liu, Weipeng Wang, Hongjian Zhang, Xuechu Zhen.

  Epidemiologic data reveal that diabetes patients taking metformin exhibit lower incidence of stroke and better functional outcomes during post-stroke neurologic recovery. We previously demonstrated that chronic post-ischemic administration of metformin improved functional recovery in experimental cerebral ischemia. However, few beneficial effects of metformin on the acute phase of cerebral ischemia were reported either in experimental animals or in stroke patients, which limits the application of metformin in stroke. We hypothesized that slow cellular uptake of metformin hydrochloride may contribute to the lack of efficacy in acute stroke. We recently developed and patented a novel metformin derivative, metformin threonate (SHY-01). Pharmacokinetic profile in vivo and in cultured cells revealed that metformin is more rapidly uptaken and accumulated from SHY-01 than metformin hydrochloride. Accordingly, SHY-01 treatment exhibited more potent and rapid activation of AMP-activated protein kinase (AMPK). Furthermore, SHY-01 elicited a stronger inhibition of microglia activation and more potent neuroprotection when compared to metformin hydrochloride. SHY-01 administration also had superior beneficial effects on neurologic functional recovery in experimental stroke and offered strong protection against acute cerebral ischemia with reduced infarct volume and mortality, as well as the improved sensorimotor and cognitive functions in rats. Collectively, these results indicated that SHY-01 had an improved pharmacokinetic and pharmacological profile and produced more potent protective effects on acute stroke and long-term neurological damage. We propose that SHY-01 is a very promising therapeutic candidate for cerebral ischemic stroke.

Keywords:  functional recovery; ischemic stroke; metformin threonate; microglia; neuroinflammation

DOI:  https://doi.org/10.3389/fphar.2022.879690
Phytother Res. 2022 Jul 06.

Bryodulcosigenin attenuates bleomycin-induced pulmonary fibrosis via inhibiting AMPK-mediated mesenchymal epithelial transition and oxidative stress.

Yue Ding, Lei Wang, Bei Liu, Guoqing Ren, Ryosuke Okubo, Jing Yu, Chaofeng Zhang.

  Fibrosis is a pathological result of a dysfunctional repair response to tissue injury and occurs in several organs, including the lungs. Bryodulcosigenin (BDG) is a cucurbitane-type triterpene isolated from Siratia grosvenori and has clear-cut anti-inflammatory effects, yet its benefit of pulmonary fibrosis (PF) remains unclear. In this study, we investigated the protective effects of BDG (10 mg/kg/day, for 14 days) against TGF-β1-stimulated mouse alveolar epithelial MLE-12 cells and bleomycin (BLM)-induced PF mice. In vitro experiments showed that BDG could inhibit epithelial-mesenchymal transition (EMT) and oxidative stress. In vivo experiments indicated that BDG could ameliorate BLM-induced PF in mice as evidenced by characteristic structural changes in histopathology, increased collagen deposition and reduced survival and weight of mice. The abnormal increased expressions of TGF-β1, p-Smad2/3, α-SMA, COL-I, and NOX4 and decreased expressions for Sirt1 and p-AMPK were improved in BDG treatment. But these beneficial effects could be eliminated by co-treatment with Compound C (CC, a selective AMPK inhibitor). Molecular docking technology also revealed the potential of BDG to activate AMPK. In summary, AMPK activation modulated by BDG not only ameliorated TGF-β1/Smad2/3 signaling pathways but also partially mediated the suppression effects on EMT and oxidative stress, thus mediating the anti-fibrotic effects.

Keywords:  AMPK activation; bryodulcosigenin; epithelial-mesenchymal transition; pulmonary fibrosis

DOI:  https://doi.org/10.1002/ptr.7535
Anim Nutr. 2022 Sep;10 234-242

AMPK-ChREBP axis mediates de novo milk fatty acid synthesis promoted by glucose in the mammary gland of lactating goats.

Hengbo Shi, Nannan Jiang, Ling Wei, Jie Cai, Wenying Zhang, Qianming Jiang, Juan J Loor, Jianxin Liu.

  To investigate the role of glucose in regulating milk fatty acid synthesis, 6 lactating Guanzhong dairy goats were infused with 0, 60, or 100 g/d glucose via the external pubic artery in a 3 × 3 repeated Latin square experiment. A concomitant in vitro experiment was conducted to investigate possible mechanisms whereby glucose regulates milk fatty acid synthesis. RNA sequencing was used for cellular transcriptome analysis. Drugs, MK-2206, rapamycin, and dorsomorphin were used to block cellular mammalian AMP-activated protein kinase (AMPK), AKT serine/threonine kinase 1, and mechanistic target of rapamycin kinase signaling pathways, respectively. Carbohydrate response element binding protein (ChREBP) was knockdown and overexpressed to investigate its role in regulating milk fatty acid synthesis in mammary epithelial cells. Glucose infusion linearly elevated the concentration of C8:0 (P = 0.039) and C10:0 (P = 0.041) in milk fat while it linearly decreased (P = 0.049) that of C16:0. This result was in agreement with the upregulation of genes related to de novo synthesis of fatty acids and lipid droplet formation, including adipose differentiation-related protein, butyrophilin subfamily 1 member A1, fatty acid synthase (FASN) and ChREBP. Their expression increased (P < 0.05) linearly in the lactating goat mammary gland. In vitro, glucose linearly stimulated the expression of genes related to de novo synthesis of fatty acids and cellular triacylglycerol in cultured mammary epithelial cells. RNA sequencing and inhibition studies revealed that glucose induced transcriptomic changes increasing lipogenic pathways, with AMPK responding to glucose by controlling ChREBP and FASN. Knockdown and overexpression of ChREBP highlighted its essential role in lipogenesis. The knockdown and overexpression of ChREBP protein also revealed an essential role in regulating the de novo synthesis of fatty acids. Collectively, our data highlight that glucose supplementation promotes de novo fatty acid synthesis via the AMPK-ChREBP axis, hence increasing milk fat yield in the goat mammary gland. Results from the current study provide possible strategies to manipulate the fatty acid composition as well as improve ruminant milk quality.

Keywords:  Carbohydrate response element binding protein; De novo synthesis; Glucose infusion; Mammary gland; Milk fat

DOI:  https://doi.org/10.1016/j.aninu.2022.05.003
J Cell Mol Med. 2022 Jul 05.

Resveratrol, novel application by preconditioning to attenuate myocardial ischemia/reperfusion injury in mice through regulate AMPK pathway and autophagy level.

Haiyan Li, Fuchun Zheng, Yanmei Zhang, Jiajia Sun, Fenfei Gao, Ganggang Shi.

  Myocardial ischemia/reperfusion injury (MI/RI) is the main cause of deaths in the worldwide, leading to severe cardiac dysfunction. Resveratrol (RSV) is a polyphenol plant-derived compound. Our study aimed to elucidate the underlying molecular mechanism of preconditioning RSV in protecting against MI/RI. Mice were ligated and re-perfused by the left anterior descending branch with or without RSV (30 mg/kg·ip) for 7 days. Firstly, we found that RSV pretreatment significantly alleviated myocardial infarct size, improved cardiac function and decreased oxidative stress. Furthermore, RSV activated p-AMPK and SIRT1, ameliorated inflammation including the level of TNF-α and IL-1β, and promoting autophagy level. Moreover, neonatal rat ventricular myocytes (NRVMs) and H9c2 cells with knockdown the expression of AMPK, SIRT1 or FOXO1 were used to uncover the underlying molecular mechanism for the cardio-protection of RSV. In NRVMs, RSV increased cellular viability, decreased LDH release and reduced oxidative stress. Importantly, Compound C(CpC) and EX527 reversed the effect of RSV against MI/RI in vivo and in vitro and counteracted the autophagy level induced by RSV. Together, our study indicated that RSV could alleviate oxidative stress in cardiomyocytes through activating AMPK/SIRT1-FOXO1 signallingpathway and enhanced autophagy level, thus presenting high potential protection on MI/RI.

Keywords:  AMPK; FOXO1; SIRT1; autophagy; myocardial ischemia/reperfusion injury; resveratrol

DOI:  https://doi.org/10.1111/jcmm.17431
Diabetes Obes Metab. 2022 Jul 08.

The SGLT2 inhibitor ertugliflozin modifies the signature of cardiac substrate metabolism and reduces cardiac mTOR-signaling, endoplasmic reticulum stress and apoptosis.

Julia Moellmann, Pascal A Mann, Ben A Kappel, Florian Kahles, Barbara M Klinkhammer, Peter Boor, Rafael Kramann, Bart Ghesquiere, Corinna Lebherz, Nikolaus Marx, Michael Lehrke.

   AIM: Sodium-glucose cotransporter 2 (SGLT2) inhibition reduces heart failure (HF) hospitalization in patients with and without diabetes. The underlying mechanisms remain incompletely understood but might relate to the induction of a fasting-like state with low blood glucose and insulin levels and increased ketone body concentrations. This study aimed to investigate cardiac signaling pathways connecting substrate utilization with left ventricular remodeling in a murine pressure overload model.
METHODS AND RESULTS: Cardiac hypertrophy was induced by transverse aortic constriction (TAC) surgery in 20-week-old C57BL/6J mice treated with or without the SGLT2 inhibitor ertugliflozin (225 mg/kg chow diet) for 10 weeks. Ertugliflozin improved left ventricular function and reduced myocardial fibrosis. This occurred simultaneously with a fasting-like response characterized by improved glucose tolerance and increased ketone body concentrations. While cardiac insulin signaling was reduced in response to SGLT2 inhibition, AMP-activated protein kinase (AMPK)-signaling was increased with induction of the fatty acid transporter cluster of differentiation 36 (CD36) and phosphorylation of acetyl-CoA carboxylase (ACC). Further, enzymes responsible for ketone body catabolism (β-hydroxybutyrate dehydrogenase (BDH1), succinyl-CoA:3-oxoacid-CoA transferase (SCOT) and acetyl-CoA acetyltransferase (ACAT) 1) were induced by SGLT2 inhibition. Ertugliflozin led to more cardiac abundance of fatty acids, tricarboxylic acid (TCA) cycle metabolites and adenosine triphosphate (ATP). Downstream mechanistic target of rapamycin (mTOR) pathway, relevant for protein synthesis, cardiac hypertrophy and adverse cardiac remodeling was reduced by SGLT2 inhibition with alleviation of endoplasmic reticulum (ER) stress and unfolded protein response (UPR) providing a potential mechanism for abundant reduced left ventricular apoptosis and fibrosis.
CONCLUSION: SGLT2 inhibition reduced left ventricular fibrosis in a murine model of cardiac hypertrophy. Mechanistically, this was associated with reduced cardiac insulin- and increased AMPK-signaling as a potential mechanism for less cardiac mTOR-activation with alleviation of downstream ER stress, UPR and apoptosis. This article is protected by copyright. All rights reserved.

Keywords:  SGTL2 inhibitors; ertugliflozin; fasting-like state; heart failure; mTOR; substrate metabolism

DOI:  https://doi.org/10.1111/dom.14814
Mol Nutr Food Res. 2022 Jul 07. e2101169

Heterophyllin B an Active Cyclopeptide Alleviates Dextran Sulfate Sodium-induced Colitis by Modulating Gut Microbiota and Repairing Intestinal Mucosal Barrier via AMPK Activation.

Ce Chen, Han Liang, Jiaoyang Wang, Guoqing Ren, Renshi Li, Zheng-Guo Cui, Chaofeng Zhang.

   SCOPE: Advances in pathology broaden our perception of the intimate interaction between gut microbiota dysbiosis and the pathogenesis of ulcerative colitis (UC), but the potential modulating roles remain to be elucidated.
METHODS AND RESULTS: DSS-induced colitis was used to investigate the effect of Heterophyllin B (HB), a typical active cyclopeptide extracted from Pseudostellaria heterophylla, on colitis and gut microbiota. Administration of HB substantially mitigated the symptoms of UC as evidenced by increasing body weight and colon length, as well as decreased macrophages infiltration in the colon. Meanwhile, HB significantly alleviated intestinal mucosal barrier dysfunction by reducing the production of inflammatory cytokines, while all the mentioned beneficial effects were significantly eliminated by co-treatment with compound C, a selective AMPK inhibitor. In addition, 16S rDNA gene analyses and fecal microbiota transplantation also revealed that HB dramatically prevented against UC by reshaping intestinal dysbiosis, especially elevated the relative abundance of Akkermansia muciniphila.
CONCLUSION: These findings illustrated that HB prominently improved intestinal epithelial homeostasis via activating AMPK and ameliorated the colonic inflammation in a gut microbiota-dependent manner, which provide evidence for microbial contribution to UC pathogenesis and suggesting a novel approach for colitis prevention. This article is protected by copyright. All rights reserved.

Keywords:  AMPK; Akkermansia muciniphila; gut microbiota; heterophyllin B; ulcerative colitis

DOI:  https://doi.org/10.1002/mnfr.202101169
Cardiovasc Toxicol. 2022 Jul 09.

Salvianolic Acid B Alleviates Myocardial Ischemia Injury by Suppressing NLRP3 Inflammasome Activation via SIRT1-AMPK-PGC-1α Signaling Pathway.

Qingju Li, Zhi Zuo, Yunzheng Pan, Qi Zhang, Li Xu, Baoping Jiang.

  Salvianolic acid B (SalB) has been extensively investigated in our laboratory for myocardial ischemia (MI) disease. This study mainly aimed to illustrate the relationship between SIRT1 and the therapeutic effect of SalB on MI in rats and hypoxia damage in H9c2 cells. Furthermore, whether the antagonism of NLRP3 by SalB in the injuries mentioned above is related to SIRT1-AMPK-PGC-1α pathway-mediated mitochondrial biogenesis was further investigated. In vivo, 24 h after MI surgery, we found that SalB effectively reduced ST-segment elevation, myocardial infarct size enlargement, cardiac injury markers, myocardial structural abnormalities, and myocardial apoptotic cells in MI injury rats. In vitro, after 4 h of hypoxia exposure, SalB alleviated cell injury, inhibited the production of ROS and IL-1β, and prevented the loss of mitochondrial membrane potential (MMP). Besides, SalB downregulated the critical components of the NLRP3 inflammasome and upregulated the SIRT1-AMPK-PGC-1α signaling pathway-related molecules in myocardial tissues and H9c2 cells. However, all the above protective effects of SalB on MI could be offset by EX527. Taken together, our findings indicated that SalB could attenuate MI injury by targeting NLRP3, which is at least partially dependent on the SIRT1/AMPK/PGC-1α signaling pathway.

Keywords:  Myocardial ischemia; NLRP3; SIRT1-AMPK-PGC-1α; Salvianolic acid B

DOI:  https://doi.org/10.1007/s12012-022-09760-8
Immunopharmacol Immunotoxicol. 2022 Jul 04. 1-35

The AMPK-SIRT1-FoxO1-NF-κB signaling pathway participates in Hesperetin-mediated neuroprotective effects against traumatic brain injury via the NLRP3 inflammasome.

Hai Song, Zhongyun Ding, Jilin Chen, Tingbao Chen, Tinghua Wang, Jin Huang.

   BACKGROUND: Traumatic brain injury (TBI) induces inflammations that lead to secondary damage. Hesperetin (Hes) exerts anti-inflammatory activities against central nervous system (CNS) diseases. This article probes the possible neuroprotective effect and mechanism of Hes on TBI-induced acute cerebral damage.
METHODS: Male C57BL/6J mice were subjected to controlled cortical impingement (CCI) and Hes (50 mg/kg) treatment after the surgery. Short-term neurological deficits were assessed with the modified neurological severity score (mNSS) and the Rota-rod test. The brain edema was tested by the wet/dry method. Neuron apoptosis was evaluated by Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. The blood-brain barrier (BBB) integrity was measured by Evans' blue staining, and immunohistochemistry (IHC) was conducted to study BV2 microglial activation. BV2 microglia and HT22 neuronal cells were stimulated by oxygen-glucose deprivation followed by recovery (OGD/R) and processed with Hes. Quantitative real-time-polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were implemented to gauge the expression of inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-β (IL-1-β) and interleukin-6 (IL-6). Western blot (WB) was performed to check AMPK-SIRT1-FoxO1 both in vitro and in vivo.
RESULTS: Hes eased neurological deficits, cerebral edema, and neuronal apoptosis in mice following TBI. Hes hampered microglial activation and pro-inflammatory cytokines production. Hes promoted AMPK and SIRT1 expression, whereas repressed the phosphorylation of FoxO1-NF-κB, and inhibited NLRP3 expression. The AMPK inhibitor Compound C markedly reversed Hes-mediated anti-inflammatory and neuron-protective effects.
CONCLUSION: Hes curbs microglial activation-mediated inflammation via the AMPK-SIRT1-FoxO1-NF-κB axis, thereby improving neurobehavioral function after TBI.

Keywords:  Hesperetin; NLRP3; inflammation; microglial activation; traumatic brain injury

DOI:  https://doi.org/10.1080/08923973.2022.2096464
Front Vet Sci. 2022 ;9 936250

Effects of N-Acetyl-L-Cysteine on Serum Indices and Hypothalamic AMPK-Related Gene Expression Under Chronic Heat Stress.

Zhengqing Li, Yulan Zhao, Yu Zhuang, Zheng Xu, Cong Wu, Ping Liu, Guoliang Hu, Guyue Li, Wei Chen, Xiaona Gao, Xiaoquan Guo.

  This study aims to investigate the effect of heat stress on the physiological metabolism of young laying hens and whether N-acetyl-l-cysteine (NAC) can effectively alleviate heat stress. 120 Hy-Line Brown laying hens aged 12 weeks were randomly divided into four groups: the control group (fed on basal diet under thermal neutral condition), HS group (fed on basal diet under heat stress condition), CN group (fed on the basic meal supplemented with 1,000 mg NAC per kg under thermal neutral condition), and HS+N group (fed on the basic meal was supplemented with 1000 mg NAC per kg under heat stress condition). The HS and HS+N groups were exposed to 36 ± 1°C for 10 h/day. The effects of NAC on the changes of serum concentrations of T3, T4, and CORT and hypothalamic gene and protein expressions induced by heat stress were measured. Results showed that heat stress upregulated the contents of T3, T4, and CORT, while NAC reduced the contents of T3, T4, and CORT. In addition, NAC downregulated AgRP expression, while upregulated the expression of POMC. Moreover, the expressions of AMPKα1, LKB1, and CPT1 were inhibited by NAC, while the expressions of AKT1, ACC, GPAT, and PPARα were increased after NAC treatment, and HMGR did not change significantly. Western blot and comprehensive immunofluorescence section of AMPK in the hypothalamus showed that NAC attenuated the activity of AMPK. In conclusion, NAC can enhance the resistance of laying hens to heat stress by alleviating the metabolic disorders of serum T3, T4, and CORT induced by heat stress, inhibiting the activation of the AMPK pathway and regulating the expression of appetite-related genes in the hypothalamus.

Keywords:  AMPK pathway; N-acetyl-l-cysteine; appetite; heat stress; hypothalamus

DOI:  https://doi.org/10.3389/fvets.2022.936250
Open Med (Wars). 2022 ;17(1): 365-374

Cardiac contractility modulation ameliorates myocardial metabolic remodeling in a rabbit model of chronic heart failure through activation of AMPK and PPAR-α pathway.

Feifei Zhang, Litian Liu, Yuetao Xie, Jiaqi Wang, Xuefeng Chen, Shihang Zheng, Yingxiao Li, Yi Dang.

  Metabolic remodeling contributes to the pathological process of heart failure (HF). We explored the effects of cardiac contractility modulation (CCM) on myocardial metabolic remodeling in the rabbit model with HF. The HF in rabbit model was established by pressure uploading and then CCM was applied. We evaluated the cardiac structure and function by echocardiography, serum BNP level, and hematoxylin and eosin and Masson's trichrome staining. We detected the accumulation of glycogen and lipid droplets in myocardial tissues by periodic acid-Schiff and Oil Red O staining. Then, we measured the contents of glucose, free fatty acid (FFA), lactic acid, pyruvate, and adenosine triphosphate (ATP) levels in myocardial tissues by corresponding kits and the expression levels of key factors related to myocardial substrate uptake and utilization by western blotting were analyzed. CCM significantly restored the cardiac structure and function in the rabbit model with HF. CCM therapy further decreased the accumulation of glycogen and lipid droplets. Furthermore, CCM reduced the contents of FFA, glucose, and lactic acid, and increased pyruvate and ATP levels in HF tissues. The protein expression levels related to myocardial substrate uptake and utilization were markedly improved with CCM treatment by further activating adenosine monophosphate-activated protein kinase and peroxisome proliferator-activated receptor-α signaling pathways.

Keywords:  cardiac contractility modulation; heart failure; metabolic remodeling

DOI:  https://doi.org/10.1515/med-2022-0415
Horm Mol Biol Clin Investig. 2022 Jul 07.

Anti-oxidant effect of metformin through AMPK/SIRT1/PGC-1α/SIRT3- independent GPx1 expression in the heart of mice with endometriosis.

Rodrigo Felgueiras, Ana C Neto, Adriana R Rodrigues, Alexandra M Gouveia, Henrique Almeida, Delminda Neves.

   OBJECTIVES: Endometriosis is a gynecological disease associated with an imbalance between oxidative species production and anti-oxidative defenses. In women, endometriosis has been reported to associate with increased incidence of cardiovascular events. As such, this study aimed to analyze the oxidation-responsive AMPK/SIRT1/PGC-1α/SIRT3 pathway in the heart of a mouse model of endometriosis. The effect of metformin, an insulin-sensitizing and anti-oxidative drug with already shown positive results in endometriotic tissue was studied.
METHODS: Thirty-six female B6CBA/F1 mice were divided into 4 groups (Control-C, Surgery-induced Endometriosis and Metformin-EM (50 mg/kg/day orally administrated for 3 months), Endometriosis-E and Metformin-M). Immunofluorescent labelling of SIRT1 and SIRT3 was performed in the heart tissue. Assessment of expression of AMPKα, SIRT1, PGC-1α, SIRT3, SOD2, and GPx1 was performed by Western Blotting. The quantification of microRNA(miR)-34a, miR-195, miR-217, miR-155 and miR-421, involved in the regulation of expression of SIRT1 and SIRT3, was performed by Real-Time PCR.
RESULTS: Data showed an increase in phospho-AMPKα and in GPx1 expression in the EM group when compared to the C group, but not in the total AMPK, SIRT1, PGC-1α, SIRT3 and SOD2, suggesting a GPx1 expression increase independently of the AMPK/SIRT1/PGC-1α/SIRT3 pathway. MicroRNAs, excepting miR-217, showed a consistent trend of increase in the M group.
CONCLUSIONS: Our study showed that endometriosis does not significantly affect the expression of the components of the AMPK/SIRT1/PGC-1α/SIRT3 pathway in the heart. However, it indicates that an oxidative condition underlying endometriosis is required for metformin to evidence an increment in the expression of the anti-oxidative enzyme GPx1.

Keywords:  AMPK; cardiovascular disease; endometriosis; glutathione peroxidase 1; metformin

DOI:  https://doi.org/10.1515/hmbci-2022-0039
Molecules. 2022 Jun 27. pii: 4114. [Epub ahead of print]27(13):

Identification of a Hydrogen-Sulfide-Releasing Isochroman-4-One Hybrid as a Cardioprotective Candidate for the Treatment of Cardiac Hypertrophy.

Yu Wang, Yuechen Liu, Hongyu Wu, Shengtao Xu, Fenfen Ma.

  Cardiac pathological hypertrophy is associated with undesirable epigenetic changes and causes maladaptive cardiac remodeling and heart failure, leading to high mortality rates. Specific drugs for the treatment of cardiac hypertrophy are still in urgent need. In the present study, a hydrogen-sulfide-releasing hybrid 13-E was designed and synthesized by appending p-hydroxythiobenzamide (TBZ), an H2S-releasing donor, to an analog of our previously discovered cardioprotective natural product XJP, 7,8-dihydroxy-3-methyl-isochromanone-4. This hybrid 13-E exhibited excellent H2S-generating ability and low cellular toxicity. The 13-E protected against cardiomyocyte hypertrophy In Vitro and reduced the induction of Anp and Bnp. More importantly, 13-E could reduce TAC-induced cardiac hypertrophy In Vivo, alleviate cardiac interstitial fibrosis and restore cardiac function. Unbiased transcriptomic analysis showed that 13-E regulated the AMPK signaling pathway and influenced fatty acid metabolic processes, which may be attributed to its cardioprotective activities.

Keywords:  AMPK; H2S donors; cardiac fibrosis; cardiac hypertrophy; hybrids; isochroman-4-one

DOI:  https://doi.org/10.3390/molecules27134114
JOR Spine. 2022 Jun;5(2): e1197

Investigation into the anti-inflammatory properties of metformin in intervertebral disc cells.

Rahul Ramanathan, Ayesha Firdous, Qing Dong, Dong Wang, Joon Lee, Nam Vo, Gwendolyn Sowa.

   Introduction: Intervertebral disc degeneration (IDD) is closely related to heightened inflammation in the annulus fibrosis (AF) and nucleus pulposus (NP) cells in the intervertebral disc. An imbalanced matrix homeostasis has been shown to contribute to disc degeneration and associated discogenic low back pain. Metformin, a diabetes medication, has been noted to exhibit anti-inflammatory properties through upregulation of the AMPK pathway, leading to various anti-inflammatory-related responses in hepatocytes. However, it is still unclear how metformin influences disc cellular response to inflammatory stress and the corresponding mechanism. Hence, the objective of this study is to elucidate the effects of metformin on expression of key pro-inflammatory, catabolic, and anabolic factors within rat AF cells in response to inflammatory stimulation and mechanical tensile stress.
Methods: Five Fischer 344 rats were sacrificed and their spines isolated. AF cells were cultured and plated in flexible silicone membrane-based six-well plates. Wells were split into eight groups and subjected to metformin, IL-1β, mechanical stretch, and combined treatments. Relative gene expressions of MMP-13, COX-2, iNOS, AGC, and Col1 were assessed with quantitative real-time polymerase chain reaction (qRT-PCR), and downstream prostaglandin E2 (PGE2) production was quantified with enzyme-linked immunosorbent assay (ELISA). NF-kB nuclear translocation was also quantified.
Results: Metformin in the presence of the combined stress treatments (M + IL/S) significantly increased Col1, COX-2, and MMP-13 gene expression, decreased PGE2 production compared to IL/S conditions alone. Metformin treatment of cultured rat annulus fibrosus cells significantly reduced the nuclear translocation of NF-κB after 4 h of IL-1β treatment from 43.1% in case of IL-1β treatment down to 26.2% in the case of metformin + IL-1β treatment.
Discussion: The lack of metformin-mediated suppression of inflammatory response in the nonstretch groups indicates that metformin may be enacting its effects through a stretch-dependent manner. These results suggest a foundation for pursuing further research into metformin's potential role as an anti-inflammatory agent for curtailing intervertebral disc degeneration.

Keywords:  AMPK pathway; NF‐kB translocation; anti‐inflammatory; anti‐inflammatory therapy; biomechanical profile of intervertebral disc; disc aging; disc mechanics; inflammatory profile of intervertebral disc; intervertebral disc degeneration; metformin therapy

DOI:  https://doi.org/10.1002/jsp2.1197
Curr Med Chem. 2022 Jul 07.

The potential therapeutic impact of metformin in glioblastoma multiforme.

Mehdi Sanati, Samaneh Aminyavari, Hamid Mollazadeh, Ali Motamed-Sanaye, Bahram Bibak, Elmira Mohtashami, Yong Teng, Amir R Afshari, Amirhossein Sahebkar.

  In terms of frequency and aggressiveness, glioblastoma multiforme (GBM) is undoubtedly the most frequent and fatal primary brain tumor. Despite advances in clinical management, the response to current treatments is dismal, with a 2-year survival rate varying between 6 and 12 percent. Metformin, a derivative of biguanide widely used in treating type 2 diabetes, has been shown to extend the lifespan of patients with various malignancies. There is limited evidence available on the long-term survival of GBM patients who have taken metformin. This research examined the literature to assess the connection between metformin's anticancer properties and GBM development. Clinical findings, together with the preclinical data from animal models and cell lines, are included in the present review. This comprehensive review covers not only the association of hyperactivation of the AMPK pathway with the anticancer activity of metformin but also other mechanisms underpinning its role in apoptosis, cell proliferation, metastasis, as well as its chemo-radio-sensitizing behavior against GBM. Current challenges and future directions for developments and applications of metformin-based therapeutics are also discussed.

Keywords:  Glioblastoma multiforme; Metformin; Anticancer; AMPK; Proliferation

DOI:  https://doi.org/10.2174/0929867329666220707103525
J Oleo Sci. 2022 ;71(7): 991-1002

Cardioprotective Effect of Gynostemma pentaphyllum against Streptozotocin Induced Cardiac Toxicity in Rats via Alteration of AMPK/Nrf2/HO-1 Pathway.

Fang Chen, Huan-Yu Zhang, Di He, Chun-Mei Rao, Bo Xu.

  Gynostemma pentaphyllum (GP) is a plant commonly used in diabetic therapy in China. GP having potent antioxidant effect against various free radicals. The purpose of the current investigation to identify the cardioprotective effect of GP against streptozotocin (STZ)/ high fat diet (HFD) induced cardiac dysfunction in rats via alteration of AMPK/Nrf2/HO-1 pathway. Wistar rats were used for the current protocol. The rats were received the intraperitoneal injection of STZ and HFD to induce the cardiac remodelling. Blood glucose level, insulin and lipid parameters were estimated. Blood pressure and heart rate were also estimated. Cardiac parameters, antioxidant, cytokines, total protein and inflammatory mediators were analysed. The mRNA expression was detected using the RT-qPCR, respectively. GP significantly (p < 0.001) decreased the BGL and improved the insulin level. GP altered the ratio of heart/BW, liver/BW, and lung/BW. GP treatment significantly (p < 0.001) suppressed the heart rate and blood pressure (diastolic, systolic and mean pressure). GP significantly (p < 0.001) reduced the level of TC, LDL, TG, VLDL and increased the level of HDL. DCM induced rats received the GP administration exhibited reduction in the level of CK and LDH. GP significantly (p < 0.001) reduced the levels of MDA, hydrogen peroxide, peroxynitrite, ROS and increased the level of GSH, SOD, CAT and GPx. GP significantly (p < 0.001) reduced the levels of cytokines (TNF-α, IL-6, IL-1β) and inflammatory parameters (COX-2 and NFκB). GP significantly (p < 0.001) suppressed the NLRP3 and NF-κB expression. GP also boosted mitochondrial biogenesis by boosting the PGC-1α, HO-1 and Nrf2 expression in cardiac tissue. GP treatment showed the cardioprotective effects against STZ induced diabetic cardiac dysfunction via alteration of AMPK/Nrf2/HO-1 pathway.

Keywords:   Gynostemma pentaphyllum ; AMPK; HO-1; Nrf2; cardiac parameters; inflammation; oxidative stress

DOI:  https://doi.org/10.5650/jos.ess21281
Biosci Biotechnol Biochem. 2022 Jul 04. pii: zbac103. [Epub ahead of print]

The effects of Formoterol in preventing adipogenesis and obesity are mediated by PPARγ/C/EBPα axis and AMPK/PGC-1α pathway.

Xiaoli Zhang, Liqun Che, Jie Shan, Yanbing Wang, Yuanyuan Jia, Hongjing Wu.

  Recent work suggests that Formoterol could be involved in the metabolic regulation of adipose tissue. It's unknown whether Formoterol possesses an effect against adipogenesis. Here, we found that Formoterol prevented adipocyte differentiation by reducing lipid accumulation, evidenced by reduced Oil Red O staining, declined intracellular triglyceride level, and downregulation of adipogenic factors (PPAR-γ, C/EBPα, and Glut4) in differentiation medium (MDI) stimulated 3T3-L1 preadipocytes. The administration of Formoterol ameliorated obesity in high fat diet (HFD) fed mice, which was evidenced by decreased body weight and ratio of fat/body weight, reduced adipocyte size, and decreased visceral adipocyte tissue weight. Furthermore, the expression level of adipogenic factors in white adipocyte tissues of HFD-fed mice was greatly repressed by Formoterol. Lastly, thermogenic markers (p-AMPK/AMPK, PGC-1α, and UCP-1) were dramatically upregulated by Formoterol. Collectively, Formoterol prevented adipogenesis and obesity in obese mice by regulating the PPARγ/C/EBPα axis and the AMPK/PGC-1α pathway.

Keywords:  AMPK; Formoterol; PPAR-γ; adipogenesis; obesity

DOI:  https://doi.org/10.1093/bbb/zbac103
Hum Cell. 2022 Jul 07.

Long noncoding RNA TRG-AS1 protects against glucocorticoid-induced osteoporosis in a rat model by regulating miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.

Wen Liu, Guojuan Li, Jing Li, Wei Chen.

  The long-term treatment of glucocorticoids is a common cause of osteoporosis (OP). This study concentrated on inquiring into the regulatory role and potential mechanisms of TRG-AS1 on dexamethasone (Dex)-induced OP in rats. We adopted Dex to treat rat osteoblasts and rats to simulate in-vitro and in-vivo OP models, respectively. Gain-of-function assays of TRG-AS1, miR-802 and CAB39 were constructed in rat osteoblasts to make certain the influence of TRG-AS1, miR-802 and CAB39 on differentiation, proliferation and apoptosis of rat osteoblasts. TRG-AS1 and CAB39 were down-regulated in the Dex-induced OP model in rats, in contrast to miR-802. Overexpression of TRG-AS1 restrained Dex-induced inhibition of osteogenic differentiation, promoted CAB39/AMPK/SIRT-1 and inhibited NF-κB, while overexpression of miR-802 bridled the inhibitory effect of TRG-AS1 on OP. miR-802 was targeted by TRG-AS1, and inhibited CAB39. Inhibition of either AMPK or SIRT-1 abated the osteogenic differentiation-promoting effect of CAB39. Animal experiments displayed that overexpressing TRG-AS1 alleviated Dex-induced OP in rats. In conclusion, up-regulation of TRG-AS1 protected against glucocorticoid-induced OP in rats by modulating the miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.

Keywords:  AMPK; CAB39; Glucocorticoid; NF-κB; Osteoporosis; SIRT-1; TRG-AS1; miR-802

DOI:  https://doi.org/10.1007/s13577-022-00741-1
Acta Pharmacol Sin. 2022 Jul 06.

Methyl eugenol protects the kidney from oxidative damage in mice by blocking the Nrf2 nuclear export signal through activation of the AMPK/GSK3β axis.

Bai-Cheng Kuang, Zhi-Heng Wang, Shuai-Heng Hou, Ji Zhang, Meng-Qin Wang, Jia-Si Zhang, Kai-Lun Sun, Hai-Qiang Ni, Nian-Qiao Gong.

  Disrupted redox homeostasis contributes to renal ischemia-reperfusion (IR) injury. Abundant natural products can activate nuclear factor erythroid-2-related factor 2 (Nrf2), thereby providing therapeutic benefits. Methyl eugenol (ME), an analog of the phenolic compound eugenol, has the ability to induce Nrf2 activity. In this study, we investigated the protective effects of ME against renal oxidative damage in vivo and in vitro. An IR-induced acute kidney injury (AKI) model was established in mice. ME (20 mg·kg-1·d-1, i.p.) was administered to mice on 5 consecutive days before IR surgery. We showed that ME administration significantly attenuated renal destruction, improved the survival rate, reduced excessive oxidative stress and inhibited mitochondrial lesions in AKI mice. We further demonstrated that ME administration significantly enhanced Nrf2 activity and increased the expression of downstream antioxidative molecules. Similar results were observed in vitro in hypoxia/reoxygenation (HR)-exposed proximal tubule epithelial cells following pretreatment with ME (40 μmol·L-1). In both renal oxidative damage models, ME induced Nrf2 nuclear retention in tubular cells. Using specific inhibitors (CC and DIF-3) and molecular docking, we demonstrated that ME bound to the binding pocket of AMPK with high affinity and activated the AMPK/GSK3β axis, which in turn blocked the Nrf2 nuclear export signal. In addition, ME alleviated the development of renal fibrosis induced by nonfatal IR, which is frequently encountered in the clinic. In conclusion, we demonstrate that ME modulates the AMPK/GSK3β axis to regulate the cytoplasmic-nuclear translocation of Nrf2, resulting in Nrf2 nuclear retention and thereby enhancing antioxidant target gene transcription that protects the kidney from oxidative damage.

Keywords:  AMPK/GSK3β; Nrf2; acute kidney injury; methyl eugenol; oxidative damage; proximal tubule epithelial cells

DOI:  https://doi.org/10.1038/s41401-022-00942-2