bims-amsmem 2022-07-03 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022‒07‒03
28 papers selected by
Dipsikha Biswas, Københavns Universitet

LKB1 is the gatekeeper of carotid body chemosensing and the hypoxic ventilatory response.
Caffeic Acid Phenethyl Ester (CAPE) Improves Boar Sperm Quality and Antioxidant Capacity in Liquid Preservation (17°C) Linked to AMPK Activity Maintenance.
Interleukin 7 inhibit autophagy via P53 regulated AMPK/mTOR signaling pathway in non-small cell lung cancer.
Understanding the Mechanism Underlie the Antidiabetic Activity of Oleuropein Using Ex-Vivo Approach.
Molecular Docking Approach of Bryophyllum Pinnatum Compounds as Atherosclerosis Therapy By Targeting Adenosine Monophosphate-Activated Protein Kinase and Inducible Nitric Oxide Synthase.
C. elegans monitor energy status via the AMPK pathway to trigger innate immune responses against bacterial pathogens.
Perisciatic Nerve Dexmedetomidine Alleviates Spinal Oxidative Stress and Improves Peripheral Mitochondrial Dynamic Equilibrium in a Neuropathic Pain Mouse Model in an AMPK-Dependent Manner.
Empagliflozin mitigates type 2 diabetes-associated peripheral neuropathy: a glucose-independent effect through AMPK signaling.
Beneficial effects of the direct AMP-Kinase activator PXL770 in in vitro and in vivo models of X-Linked Adrenoleukodystrophy .
TRIOL Inhibits Rapid Intracellular Acidification and Cerebral Ischemic Injury: The Role of Glutamate in Neuronal Metabolic Reprogramming.
Redox-dependent AMPK inactivation disrupts metabolic adaptation to glucose starvation in xCT-overexpressing cancer cells.
Bone morphogenetic protein inhibitors and mitochondria targeting agents synergistically induce apoptosis-inducing factor (AIF) caspase-independent cell death in lung cancer cells.
C1q/tumour necrosis factor-related protein-3 alleviates high-glucose-induced lipid accumulation and necroinflammation in renal tubular cells by activating the adenosine monophosphate-activated protein kinase pathway.
Mitigation of honokiol on fluoride-induced mitochondrial oxidative stress, mitochondrial dysfunction, and cognitive deficits through activating AMPK/PGC-1α/Sirt3.
Integration of bioassay and non-target metabolite analysis of tomato reveals that β-carotene and lycopene activate the adiponectin signaling pathway, including AMPK phosphorylation.
Acyclovir alleviates insulin resistance via activating PKM1 in diabetic mice.
Citrus maxima and tea regulate AMPK signaling pathway to retard the progress of nonalcoholic fatty liver disease.
Glycocalyx heparan sulfate cleavage promotes endothelial cell angiopoietin-2 expression by impairing shear stress-related AMPK/FoxO1 signaling.
Single-Cell Multiplex qPCR Evidence for Sex-Dimorphic Glutamate Decarboxylase, Estrogen Receptor, and 5'-AMP-Activated Protein Kinase Alpha Subunit mRNA Expression by Ventromedial Hypothalamic Nucleus GABAergic Neurons.
Galectin-3 induces vascular smooth muscle cells calcification via AMPK/TXNIP pathway.
PINK1/Parkin Pathway Activation for Mitochondrial Quality Control - Which Is the Best Molecular Target for Therapy?
Salvianolic acid A promotes mitochondrial biogenesis and function via regulating the AMPK/PGC-1α signaling pathway in HUVECs.
TET3 Mediates 5hmC Level and Promotes Tumorigenesis by Activating AMPK Pathway in Papillary Thyroid Cancer.
Phosphoproteomics reveals that camel and goat milk improve glucose homeostasis in HDF/STZ-induced diabetic rats through activation of hepatic AMPK and GSK3-GYS axis.
Zhen-Wu-Tang Induced Mitophagy to Protect Mitochondrial Function in Chronic Glomerulonephritis via PI3K/AKT/mTOR and AMPK Pathways.
Modulation of endoplasmic reticulum stress via sulforaphane-mediated AMPK upregulation against nonalcoholic fatty liver disease in rats.
Methyl Gallate Suppresses the Migration, Invasion, and Epithelial-Mesenchymal Transition of Hepatocellular Carcinoma Cells via the AMPK/NF-κB Signaling Pathway in vitro and in vivo.
Stigmasterol attenuates inflammatory response of microglia via NF-κB and NLRP3 signaling by AMPK activation.

Commun Biol. 2022 Jun 29. 5(1): 642

LKB1 is the gatekeeper of carotid body chemosensing and the hypoxic ventilatory response.

Sandy MacMillan, Andrew P Holmes, Mark L Dallas, Amira D Mahmoud, Michael J Shipston, Chris Peers, D Grahame Hardie, Prem Kumar, A Mark Evans.

The hypoxic ventilatory response (HVR) is critical to breathing and thus oxygen supply to the body and is primarily mediated by the carotid bodies. Here we reveal that carotid body afferent discharge during hypoxia and hypercapnia is determined by the expression of Liver Kinase B1 (LKB1), the principal kinase that activates the AMP-activated protein kinase (AMPK) during metabolic stresses. Conversely, conditional deletion in catecholaminergic cells of AMPK had no effect on carotid body responses to hypoxia or hypercapnia. By contrast, the HVR was attenuated by LKB1 and AMPK deletion. However, in LKB1 knockouts hypoxia evoked hypoventilation, apnoea and Cheyne-Stokes-like breathing, while only hypoventilation and apnoea were observed after AMPK deletion. We therefore identify LKB1 as an essential regulator of carotid body chemosensing and uncover a divergence in dependency on LKB1 and AMPK between the carotid body on one hand and the HVR on the other.

DOI: https://doi.org/10.1038/s42003-022-03583-7
Front Vet Sci. 2022 ;9 904886

Caffeic Acid Phenethyl Ester (CAPE) Improves Boar Sperm Quality and Antioxidant Capacity in Liquid Preservation (17°C) Linked to AMPK Activity Maintenance.

Qun Lan, Li'e Xue, Jiacheng Cao, Yingyu Xie, Tianfang Xiao, Shaoming Fang.

  Liquid preservation of boar sperm is crucial for artificial insemination application in pig production. However, time-dependent oxidative damage to sperm is one of the major challenges during the liquid preservation period. Caffeic acid phenethyl ester (CAPE) possesses excellent antioxidant properties and has potential therapeutic use in reproductive organ injury linked to oxidative stress. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) involves in modulating the cellular redox state and exerts a beneficial effect on sperm preservation. In the present study, we firstly assessed different concentrations of CAPE that affect sperm quality during liquid storage to determine the appropriate addition. To further investigate whether CAPE exerts protective effects on boar sperm through modulation of AMPK activity, sperm quality parameters, antioxidant capacity, and marker protein expressions were evaluated under co-incubation with H2O2. The results showed that sperm treated with 210 μmol/L CAPE exhibited the highest motion parameters (total motility and progressive motility) and best functional integrity (mitochondrial activity, plasma membrane integrity, and acrosomal integrity). Even in the presence of H2O2, the addition of 210 μmol/L CAPE not only significantly improved sperm quality parameters, but also elevated CAT, SOD, and GSH-Px activities to enhance sperm antioxidant capacity. In addition, we found that CAPE could affect the protein activities of AMPK, phospho-AMPK α (p-AMPK), SOD, and Caspase-3 regardless of whether H2O2 is present or not. Our findings suggested that CAPE has potential application in liquid preservation of boar sperm and preliminary indicated that CAPE-induced improvement of sperm quality and antioxidant capacity should be mediated through conservation of AMPK activity. Further studies are required to illustrate the specific mechanism by which CAPE attenuates oxidative stress-mediated damages dependent on AMPK activity.

Keywords:  AMPK; CAPE; antioxidant capacity; boar sperm; liquid preservation; sperm quality

DOI:  https://doi.org/10.3389/fvets.2022.904886
Sci Rep. 2022 Jul 01. 12(1): 11208

Interleukin 7 inhibit autophagy via P53 regulated AMPK/mTOR signaling pathway in non-small cell lung cancer.

Yunjia Zhu, Xi Jiang, Zhiying Ding, Jian Ming.

Interleukin 7 (IL-7) has been demonstrated regulating lymphangiogenesis, apoptosis, and proliferation. Whether IL-7 induce or inhibit autophagy in non-small cell lung cancer (NSCLC) are unknown. In this study, Western blot was used to detect cytoplasmic and nuclear protein of p53, total protein of AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Light chain 3 (LC3). Quantitative Real-Time PCR (qRT-PCR) was used to detect p53 mRNA level after treated with IL-7. Then using transmission electron microscopy to observe the morphological change of autophagosome. 123 cases of NSCLC were collected for survival analysis, immunohistochemistry staining and cox regression multivariate analysis. We find that IL-7 induce the p53 translocation from nucleus to cytoplasm, then IL-7 down-regulate phosphorylation of AMPK and up-regulate phosphorylation of mTOR. The expression of AMPK and p53 were associated with IL-7/IL-7R and mTOR expression. Clinically, AMPK and p53 were well correlated with stage and survival of lung cancer patients. IL-7R, mTOR and tumor stage were the strongest predictors of survival. In conclusion, IL-7 inhibit autophagy in NSCLC via P53 regulated AMPK/mTOR signaling pathway. AMPK and p53 are correlated with patients' survival. IL-7R, mTOR and tumor stage are the strongest predictor of survival.

DOI: https://doi.org/10.1038/s41598-022-14742-5
Rep Biochem Mol Biol. 2022 Apr;11(1): 146-156

Understanding the Mechanism Underlie the Antidiabetic Activity of Oleuropein Using Ex-Vivo Approach.

Hakam Hasan Alkhateeb, Nasser Mohammed Kaplan, Mohammed Al-Duais.

  Background: Oleuropein, the main constituent of olive fruit and leaves, has been reported to protect against insulin resistance and diabetes. While many experimental investigations have examined the mechanisms by which oleuropein improves insulin resistance and diabetes, much of these investigations have been carried out in either muscle cell lines or in vivo models two scenarios with many drawbacks. Accordingly, to simplify identification of mechanisms by which oleuropein regulates specific cellular processes, we resort, in the present study, to isolated muscle preparation which enables better metabolic milieu control and permit more detailed analyses.Methods: For this purpose, soleus muscles were incubated for 12 h without or with palmitate (1.5 mM) in the presence or absence of oleuropein (1.5 mM), and compound C. Insulin-stimulated glucose transport, glucose transporter type 4 (GLUT4) translocation, Akt substrate of 160 kDa (AS160) phosphorylation and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation were examined.
Results: Palmitate treatment reduced insulin-stimulated glucose transport, GLUT4 translocation and AS160 phosphorylation, but AMPK phosphorylation was not changed. Oleuropein administration (12 h) fully rescued insulin-stimulated glucose transport, but partially restored GLUT4 translocation. However, it fully restored AS160 phosphorylation, raising the possibility that oleuropein may also have contributed to the restoration of glucose transport by increased GLUT4 intrinsic activity. Inhibition of AMPK phosphorylation with compound C (50 µM) prevented oleuropein -induced improvements in insulin-stimulated glucose transport, GLUT4 translocation, and AS160 phosphorylation.
Conclusion: Our results clearly indicate that oleuropein alleviates palmitate-induced insulin resistance appears to occur via an AMPK-dependent mechanism involving improvements in the functionality of the AS160-GLUT4 signaling system.

Keywords:  AMPK; GLUT4; Insulin resistance; Muscle; Oleuropein

DOI:  https://doi.org/10.52547/rbmb.11.1.146
Acta Inform Med. 2022 Jun;30(2): 91-95

Molecular Docking Approach of Bryophyllum Pinnatum Compounds as Atherosclerosis Therapy By Targeting Adenosine Monophosphate-Activated Protein Kinase and Inducible Nitric Oxide Synthase.

Yuyun Yuniwati, Mokhamad Fahmi Rizki Syaban, Salsabila Ghina Anoraga, Faradilah Lukmana Sabila.

  Background: Bryophyllum pinnatum is a herbal medicine from Indonesia which has an anti-inflammatory effect. Adenosine monophosphate-activated protein kinase (AMPK) and inducible nitric oxide synthase (iNOS) play a function in thickening and inflammation in atherosclerosis disease.Objective: This research aims conducted to know the potential of Bryophyllum pinnatum as a therapy for atherosclerosis by targeting AMPK and iNOS.
Methods: We employed a molecular docking technique to interact active compounds of Bryohyllum pinnatum with AMPK and iNOS, which were retrieved on the protein databank. Molecular docking analysis utilizing tools such as Pyrx 9.5, Pymol, and Discovery Studio, to support the interaction between the compound and protein. Molecular Dynamic (MD) simulation also performed using CABS-FLEX 2.0 server to know the stability interaction.
Results: Bryophillin B was an active compound that possesses significant binding to AMPK and iNOS. It had same binding pocket as native ligand, and Bryophyllin B has a stronger interaction with AMPK. Based on the RMSF, the interaction biding complex Bryophyllin B with AMPK and iNOS were stable.
Conclusion: Bryophillin B was predicted to have potential therapy for atherosclerosis disease.

Keywords:  AMPK; Bryophyllum pinnatum; Herbal medicine; In Silico; iNOS

DOI:  https://doi.org/10.5455/aim.2022.30.91-95
Commun Biol. 2022 Jun 30. 5(1): 643

C. elegans monitor energy status via the AMPK pathway to trigger innate immune responses against bacterial pathogens.

Shouyong Ju, Hanqiao Chen, Shaoying Wang, Jian Lin, Yanli Ma, Raffi V Aroian, Donghai Peng, Ming Sun.

Pathogen recognition and the triggering of host innate immune system are critical to understanding pathogen-host interaction. Cellular surveillance systems have been identified as an important strategy for the identification of microbial infection. In the present study, using Bacillus thuringiensis-Caenorhabditis elegans as a model, we found an approach for surveillance systems to sense pathogens. We report that Bacillus thuringiensis Cry5Ba, a typical pore-forming toxin, caused mitochondrial damage and energy imbalance by triggering potassium ion leakage, instead of directly targeting mitochondria. Interestingly, we find C. elegans can monitor intracellular energy status to trigger innate immune responses via AMP-activated protein kinase (AMPK), secreting multiple effectors to defend against pathogenic attacks. Our study indicates that the imbalance of energy status is a prevalent side effect of pathogen infection. Furthermore, the AMPK-dependent surveillance system may serve as a practicable strategy for the host to recognize and defense against pathogens.

DOI: https://doi.org/10.1038/s42003-022-03589-1
Dis Markers. 2022 ;2022 6889676

Perisciatic Nerve Dexmedetomidine Alleviates Spinal Oxidative Stress and Improves Peripheral Mitochondrial Dynamic Equilibrium in a Neuropathic Pain Mouse Model in an AMPK-Dependent Manner.

Yang Mu, Yang Mei, Yaohua Chen, Yuping Li, Dan Zhu, Jian Cui, Lehua Yu.

Neuropathic pain (NPP) is a debilitating clinical condition that presently has few effective treatments. NPP is caused by uncontrolled central oxidative stress and inflammation. Preliminary studies indicate that dexmedetomidine (DEX), an agonist of the alpha-2 adrenergic receptor, is beneficial for treating NPP. In this paper, the effects of administering DEX around injured nerves in a chronic constriction injury- (CCI-) induced neuropathic pain mouse model are investigated. According to the results, the perineural DEX significantly reversed the decline in the mechanical threshold and thermal latency in CCI mice (p < 0.001). In the peripherally affected ischiadic nerve, the perineuronal DEX upregulated the expressions of pAMPK, OPA1, and SNPH but not Drp1 or KIF5B. The aforementioned effects of administering DEX can be partially reversed by compound C, a selective and reversible inhibitor of AMP-activated protein kinase (AMPK). Furthermore, it was found that perineural DEX significantly inhibited the CCI-induced upregulation of the immediate early gene c-Fos, overexpression of the inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), attenuation of the NADH dehydrogenase complexes I, II, III, and IV, and the repression of ATP, SOD, and GSH in the dorsal horn of the spinal cord (DHSC) (p < 0.01). These findings indicate that perineuronal DEX protected the injured ischiadic nerves and attenuated neuropathic pain via AMPK activation to improve energy supply in the peripheral injured nerves, alleviate the inflammatory factor release, and inhibit oxidative stress in the DHSC.

DOI: https://doi.org/10.1155/2022/6889676
Arch Pharm Res. 2022 Jun 29.

Empagliflozin mitigates type 2 diabetes-associated peripheral neuropathy: a glucose-independent effect through AMPK signaling.

Noha F Abdelkader, Marawan A Elbaset, Passant E Moustafa, Sherehan M Ibrahim.

  Diabetic peripheral neuropathy (DPN) represents a severe microvascular condition that dramatically affects diabetic patients despite adequate glycemic control, resulting in high morbidity. Thus, recently, anti-diabetic drugs that possess glucose-independent mechanisms attracted attention. This work aims to explore the potentiality of the selective sodium-glucose cotransporter-2 inhibitor, empagliflozin (EMPA), to ameliorate streptozotocin-induced DPN in rats with insight into its precise signaling mechanism. Rats were allocated into four groups, where control animals received vehicle daily for 2 weeks. In the remaining groups, DPN was elicited by single intraperitoneal injections of freshly prepared streptozotocin and nicotinamide (52.5 and 50 mg/kg, respectively). Then EMPA (3 mg/kg/p.o.) was given to two groups either alone or accompanied with the AMPK inhibitor dorsomorphin (0.2 mg/kg/i.p.). Despite the non-significant anti-hyperglycemic effect, EMPA improved sciatic nerve histopathological alterations, scoring, myelination, nerve fibers' count, and nerve conduction velocity. Moreover, EMPA alleviated responses to different nociceptive stimuli along with improved motor coordination. EMPA modulated ATP/AMP ratio, upregulated p-AMPK while reducing p-p38 MAPK expression, p-ERK1/2 and consequently p-NF-κB p65 as well as its downstream mediators (TNF-α and IL-1β), besides enhancing SOD activity and lowering MDA content. Moreover, EMPA downregulated mTOR and stimulated ULK1 as well as beclin-1. Likewise, EMPA reduced miR-21 that enhanced RECK, reducing MMP-2 and -9 contents. EMPA's beneficial effects were almost abolished by dorsomorphin administration. In conclusion, EMPA displayed a protective effect against DPN independently from its anti-hyperglycemic effect, probably via modulating the AMPK pathway to modulate oxidative and inflammatory burden, extracellular matrix remodeling, and autophagy.

Keywords:  AMPK; Diabetic peripheral neuropathy; Dorsomorphin; Empagliflozin; mTOR; p38 MAPK

DOI:  https://doi.org/10.1007/s12272-022-01391-5
J Pharmacol Exp Ther. 2022 Jun 28. pii: JPET-AR-2022-001208. [Epub ahead of print]

Beneficial effects of the direct AMP-Kinase activator PXL770 in in vitro and in vivo models of X-Linked Adrenoleukodystrophy .

Pierre-Axel Monternier, Parveen Parasar, Pierre Theurey, Pascale Gluais Dagorn, Navtej Kaur, Tavarekere N Nagaraja, Pascale Fouqueray, Sebastien Bolze, David E Moller, Jaspreet Singh, Sophie Hallakou-Bozec.

  Background: X-linked adrenoleukodystrophy (ALD) is a severe orphan disease caused by mutations in the peroxisomal ABCD1 transporter gene, leading to toxic accumulation of Very Long-Chain Fatty Acids (VLCFA - in particular C26:0) resulting in inflammation, mitochondrial dysfunction and demyelination. AMP-activated protein kinase (AMPK) is downregulated in ALD, and its activation is implicated as a therapeutic target. PXL770 is the first direct allosteric AMPK activator with established clinical efficacy and tolerability. Methods: We investigated its effects in ALD patient-derived fibroblasts/lymphocytes and Abcd1 KO mouse glial cells. Readouts included VLCFA levels, mitochondrial function and mRNA levels of proinflammatory genes and compensatory transporters (ABCD2-3). Following PXL770 treatment in Abcd1 KO mice, we assessed VLCFA levels in tissues, sciatic nerve axonal morphology by electronic microscopy and locomotor function by open-field/balance-beam tests. Results: In patients' cells and Abcd1 KO glial cells, PXL770 substantially decreased C26:0 levels (by ~90%), improved mitochondrial respiration, reduced expression of multiple inflammatory genes and induced expression of ABCD2-3 In Abcd1 KO mice, PXL770 treatment normalized VLCFA in plasma and significantly reduced elevated levels in brain (-25%) and spinal cord (-32%) vs. untreated (p<0.001). Abnormal sciatic nerve axonal morphology was also improved along with amelioration of locomotor function. Conclusion: Direct AMPK activation exerts beneficial effects on several hallmarks of pathology in multiple ALD models in vitro and in vivo, supporting clinical development of PXL770 for this disease. Further studies would be needed to overcome limitations including small sample size for some parameters, lack of additional in vivo biomarkers and incomplete pharmacokinetic characterization. Significance Statement Adrenoleukodystrophy is a rare and debilitating condition with no approved therapies, caused by accumulation of very long-chain fatty acids. AMPK is downregulated in the disease and has been implicated as a potential therapeutic target. PXL770 is a novel clinical stage direct AMPK activator. In these studies, we used PXL770 to achieve preclinical validation of direct AMPK activation for this disease - based on correction of key biochemical and functional readouts in vitro and in vivo, thus supporting clinical development.

Keywords:  Adrenal gland; Neuroinflammation; amp-dependent protein kinase (AMPK); brain/CNS; fatty acid metabolism; genetically modified animal models; mitochondria; peroxisome proliferator-activated receptors/PPAR

DOI:  https://doi.org/10.1124/jpet.122.001208
ACS Chem Neurosci. 2022 Jun 30.

TRIOL Inhibits Rapid Intracellular Acidification and Cerebral Ischemic Injury: The Role of Glutamate in Neuronal Metabolic Reprogramming.

DongDong Xue, CaiLv Wei, YueHan Zhou, Kai Wang, YuWei Zhou, Chen Chen, Yuan Li, LongXiang Sheng, BingZheng Lu, Zhu Zhu, Wei Cai, XinPeng Ning, ShengLong Li, TianYu Qi, JiaKai Pi, SuiZhen Lin, GuangMei Yan, YiJun Huang, Wei Yin.

  As one of the key injury incidents, tissue acidosis in the brain occurs very quickly within several minutes upon the onset of ischemic stroke. Glutamate, an excitatory amino acid inducing neuronal excitotoxicity, has been reported to trigger the decrease in neuronal intracellular pH (pHi) via modulating proton-related membrane transporters. However, there remains a lack of clarity on the possible role of glutamate in neuronal acidosis via regulating metabolism. Here, we show that 200 μM glutamate treatment quickly promotes glycolysis and inhibits mitochondrial oxidative phosphorylation of primary cultured neurons within 15 min, leading to significant cytosolic lactate accumulation, which contributes to the rapid intracellular acidification and neuronal injury. The reprogramming of neuronal metabolism by glutamate is dependent on adenosine monophosphate-activated protein kinase (AMPK) signaling since the inhibition of AMPK activation by its selective inhibitor compound C significantly reverses these deleterious events in vitro. Moreover, 5α-androst-3β,5α,6β-TRIOL (TRIOL), a neuroprotectant we previously reported, can also remarkably reverse intracellular acidification and alleviate neuronal injury through the inhibition of AMPK signaling. Furthermore, TRIOL remarkably reduced the infarct volume and attenuated neurologic impairment in acute ischemic stroke models of middle cerebral artery occlusion in vivo. In summary, we reveal a novel role of glutamate in rapid intracellular acidification injury resulting from glutamate-induced lactate accumulation through AMPK-mediated neuronal reprogramming. Moreover, inhibition of the quick drop in neuronal pHi by TRIOL significantly reduces the cerebral damages, suggesting that it is a promising drug candidate for ischemic stroke.

Keywords:  5α-androst-3β,5α,6β-TRIOL; glutamate; glycolysis; intracellular acidification; ischemic stroke; lactate

DOI:  https://doi.org/10.1021/acschemneuro.2c00119
J Cell Sci. 2022 Jul 01. pii: jcs.259090. [Epub ahead of print]

Redox-dependent AMPK inactivation disrupts metabolic adaptation to glucose starvation in xCT-overexpressing cancer cells.

Younghwan Lee, Yoko Itahana, Choon Chen Ong, Koji Itahana.

  Accelerated aerobic glycolysis is a distinctive metabolic property of cancer cells that confers dependency on glucose for survival. However, the therapeutic strategies targeting this vulnerability are still inefficient and have unacceptable side effects in clinical trials. Therefore, developing biomarkers to predict therapeutic efficacy would be essential to improve the selective targeting of cancer cells. Here, we found that the cell lines sensitive to glucose deprivation have high expression of cystine/glutamate antiporter xCT. We found that cystine uptake and glutamate export through xCT contributed to rapid NADPH depletion under glucose deprivation. This collapse of the redox system oxidized and inactivated AMPK, a major regulator of metabolic adaptation, resulting in a metabolic catastrophe and cell death. While this phenomenon was prevented by pharmacological or genetic inhibition of xCT, overexpression of xCT sensitized resistant cancer cells to glucose deprivation. Taken together, these findings suggest a novel cross-talk between AMPK and xCT for the metabolism and signal transduction and reveal a metabolic vulnerability in xCT-high expressing cancer cells to glucose deprivation.

Keywords:  AMPK; Cystine; Glucose starvation; NADPH; SLC7A11; xCT

DOI:  https://doi.org/10.1242/jcs.259090
Cell Commun Signal. 2022 Jun 27. 20(1): 99

Bone morphogenetic protein inhibitors and mitochondria targeting agents synergistically induce apoptosis-inducing factor (AIF) caspase-independent cell death in lung cancer cells.

Arindam Mondal, Jacques Roberge, John Gilleran, Youyi Peng, Dongxuan Jia, Moumen Akel, Yash Patel, Harrison Zoltowski, Anupama Doraiswamy, John Langenfeld.

  BACKGROUND: Bone morphogenetic proteins (BMP) are evolutionarily conserved morphogens that are reactivated in lung carcinomas. In lung cancer cells, BMP signaling suppresses AMP activated kinase (AMPK) by inhibiting LKB1. AMPK is activated by mitochondrial stress that inhibits ATP production, which is enhanced 100-fold when phosphorylated by LKB1. Activated AMPK can promote survival of cancer cells but its "hyperactivation" induces cell death. The studies here reveal novel cell death mechanisms induced by BMP inhibitors, together with agents targeting the mitochondria, which involves the "hyperactivation" of AMPK.METHODS: This study examines the synergistic effects of two BMP inhibitors together with mitochondrial targeting agents phenformin and Ym155, on cell death of lung cancer cells expressing LKB1 (H1299), LKB1 null (A549), and A549 cells transfected with LKB1 (A549-LKB1). Cell death mechanisms evaluated were the activation of caspases and the nuclear localization of apoptosis inducing factor (AIF). A769662 was used to allosterically activate AMPK. Knockdown of BMPR2 and LKB1 using siRNA was used to examine their effects on nuclear localization of AMPK. Validation studies were performed on five passage zero primary NSCLC.
RESULTS: Both BMP inhibitors synergistically suppressed growth when combined with Ym155 or phenformin in cells expressing LKB1. The combination of BMP inhibitors with mitochondrial targeting agents enhanced the activation of AMPK in lung cancer cells expressing LKB1. Allosteric activation of AMPK with A769662 induced cell death in both H1299 and A549 cells. Cell death induced by the combination of BMP inhibitors and mitochondrial-targeting agents did not activate caspases. The combination of drugs induced nuclear localization of AIF in cells expressing LKB1, which was attenuated by knockdown of LKB1. Knockdown of BMPR2 together with Ym155 increased nuclear localization of AIF. Combination therapy also enhanced cell death and AIF nuclear localization in primary NSCLC.
CONCLUSIONS: These studies demonstrate that inhibition of BMP signaling together with mitochondrial targeting agents induce AIF caspase-independent cell death, which involves the "hyperactivation" of AMPK. AIF caspase-independent cell death is an evolutionarily conserved cell death pathway that is infrequently studied in cancer. These studies provide novel insight into mechanisms inducing AIF caspase-independent cell death in cancer cells using BMP inhibitors. Video Abstract.

Keywords:  AIF; AMPK; BMP; Caspase-independent; Cell death

DOI:  https://doi.org/10.1186/s12964-022-00905-4
Int J Biochem Cell Biol. 2022 Jun 23. pii: S1357-2725(22)00092-9. [Epub ahead of print] 106247

C1q/tumour necrosis factor-related protein-3 alleviates high-glucose-induced lipid accumulation and necroinflammation in renal tubular cells by activating the adenosine monophosphate-activated protein kinase pathway.

Chunyang Du, Yan Zhu, Yan Yang, Lin Mu, Xue Yan, Ming Wu, Chenming Zhou, Haijiang Wu, Wei Zhang, Yanhui Wu, Guoyu Zhang, Yue Hu, Yunzhuo Ren, Yonghong Shi.

  Lipid accumulation and progressive necroinflammation play pivotal roles in the development of diabetic nephropathy. C1q tumour necrosis factor-related protein-3 (CTRP3) is an adipokine with pleiotropic functions in cell proliferation, glucose and lipid metabolism, and inflammation. However, the mechanism and involvement of CTRP3 in lipid metabolism and the necroinflammation of renal tubular cells remain unclear. Here, we report that CTRP3 expression decreased in a time- and concentration-dependent manner in high glucose-stimulated HK-2 cells. We noted that the overexpression of CTRP3 or recombinant CTRP3 (rCTRP3) treatment prevented high glucose-induced lipid accumulation by inhibiting the expression of sterol regulatory element-binding protein-1 and increasing the expression of peroxisome proliferator-activated receptor-α and ATP-binding cassette A1. Moreover, the nucleotide-binding oligomerisation domain-like receptor protein 3-mediated inflammatory response and mixed lineage kinase domain-like protein-dependent necroinflammation were inhibited by CTRP3 overexpression or rCTRP3 treatment in HK-2 cells cultured in high glucose. Furthermore, lipotoxicity-induced by palmitic acid was found to be involved in necroinflammation in HK-2 cells, and CTRP3 displayed the same protective effect. CTRP3 also activated the adenosine monophosphate-activated protein kinase (AMPK) pathway, whereas adenine 9-β-D-arabinofuranoside, an AMPK inhibitor, replicated the protective effects of CTRP3. Besides, using kidney biopsies from patients with diabetes, we found that decreased CTRP3 expression was accompanied by increased lipid deposition, as well as the structural and functional injury of renal tubular cells. Our findings demonstrate that CTRP3 affects lipid metabolism and necroinflammation in renal tubular cells via the AMPK signalling pathway. Thus, CTRP3 may be a potential therapeutic target in diabetic renal injury.

Keywords:  C1q/tumor necrosis factor-related protein-3; Diabetic nephropathy; Lipid accumulation; Necroinflammation; adenosine monophosphate-activated protein kinase

DOI:  https://doi.org/10.1016/j.biocel.2022.106247
J Hazard Mater. 2022 Jun 16. pii: S0304-3894(22)01174-8. [Epub ahead of print]437 129381

Mitigation of honokiol on fluoride-induced mitochondrial oxidative stress, mitochondrial dysfunction, and cognitive deficits through activating AMPK/PGC-1α/Sirt3.

Dongmei Wang, Luyang Cao, Xiang Zhou, Gang Wang, Yilu Ma, Xueqin Hao, Hua Fan.

  Oxidative stress and mitochondrial dysfunction contribute greatly to fluoride-induced cognitive impairment and behavioural disorders. Honokiol, a natural biphenolic compound, possesses antioxidant and mitochondrial protective properties. The present study investigated the protective actions of honokiol on NaF-elicited cognitive deficits and elucidated the possible mechanism of honokiol-mediated protection. The results demonstrated that honokiol administration markedly attenuated fluoride-induced cognitive impairments and neural/synaptic injury in mice. Moreover, honokiol elevated the activity and expression of SOD2 and promoted mtROS scavenging through Sirt3 activation in NaF-treated mice and SH-SY5Y cell lines. Meanwhile, honokiol substantially lowered mtROS production by enhancing Sirt3-mediated mitochondrial DNA (mtDNA) transcription, thereby leading to significant increases in ATP synthesis and complex I activity. Further studies revealed that honokiol activated AMPK and upregulated the PGC-1α and Sirt3 protein expression in vivo and in vitro. Intriguingly, the protective actions of honokiol on oxidative stress and mitochondrial dysfunction were abolished by AMPK shRNA or Sirt3 shRNA. Notably, AMPK knockdown prevented the increase in PGC-1α and Sirt3 expression induced by honokiol, while Sirt3 shRNA suppressed Sirt3 signaling without significant effects on p-AMPK and PGC-1α expression. In conclusion, our findings indicate that honokiol mitigates NaF-induced oxidative stress and mitochondrial dysfunction by regulating mtROS homeostasis, partly via the AMPK/PGC-1α/Sirt3 pathway, which ultimately contributes to neuronal/synaptic injury and cognitive deficits.

Keywords:  AMPK/PGC-1α/Sirt3; Cognitive deficits; Fluoride; Honokiol; MtROS homeostasis

DOI:  https://doi.org/10.1016/j.jhazmat.2022.129381
PLoS One. 2022 ;17(7): e0267248

Integration of bioassay and non-target metabolite analysis of tomato reveals that β-carotene and lycopene activate the adiponectin signaling pathway, including AMPK phosphorylation.

Shinsuke Mohri, Haruya Takahashi, Maiko Sakai, Naoko Waki, Shingo Takahashi, Koichi Aizawa, Hiroyuki Suganuma, Takeshi Ara, Tatsuya Sugawara, Daisuke Shibata, Yasuki Matsumura, Tsuyoshi Goto, Teruo Kawada.

Adiponectin, an adipokine, regulates glucose metabolism and insulin sensitivity through the adiponectin receptor (AdipoR). In this study, we searched for metabolites that activate the adiponectin signaling pathway from tomato (Solanum lycopersicu). Metabolites of mature tomato were separated into 55 fractions by liquid chromatography, and then each fraction was examined using the phosphorylation assay of AMP-protein kinase (AMPK) in C2C12 myotubes and in AdipoR-knockdown cells by small interfering RNA (siRNA). Several fractions showed AMPK phosphorylation in C2C12 myotubes and siRNA-mediated abrogation of the effect. Non-targeted metabolite analysis revealed the presence of 721 diverse metabolites in tomato. By integrating the activity of fractions on AMPK phosphorylation and the 721 metabolites based on their retention times of liquid chromatography, we performed a comprehensive screen for metabolites that possess adiponectin-like activity. As the screening suggested that the active fractions contained four carotenoids, we further analyzed β-carotene and lycopene, the major carotenoids of food. They induced AMPK phosphorylation via the AdipoR, Ca2+/calmodulin-dependent protein kinase kinase and Ca2+ influx, in addition to activating glucose uptake via AdipoR in C2C12 myotubes. All these events were characteristic adiponectin actions. These results indicated that the food-derived carotenoids, β-carotene and lycopene, activate the adiponectin signaling pathway, including AMPK phosphorylation.

DOI: https://doi.org/10.1371/journal.pone.0267248
Life Sci. 2022 Jun 22. pii: S0024-3205(22)00425-8. [Epub ahead of print]304 120725

Acyclovir alleviates insulin resistance via activating PKM1 in diabetic mice.

Zhuozhou Hu, Jing Zhou, Liang Han, Xiangxiang Li, Chun Li, Tongyu Wu, Jingjing Liu, Wenyang Zhao, Jia Kang, Xinping Chen.

  AIMS: Diabetes mellitus (DM) is a major global health threat characterized by insulin resistance. A new tactic to ameliorate insulin resistance, thereby reversing the exacerbation of DM, is urgently needed. The work is aiming to provide a new strategy for DM treatment as well as to identify new targets.MAIN METHODS: C57BL/6 N mice were raised with high-fat diet (HFD) and infused with streptozotocin (STZ) to induce diabetes. The blood glucose, serum insulin, blood lipid and oxidative stress were detected. In vitro insulin resistance model experiment has been made to examine the molecular mechanisms underlying anti-diabetic effect of potential active chemicals in human hepatocellular carcinoma cells (HepG2).
KEY FINDINGS: Acyclovir, an antiviral nucleotide analog, alleviates insulin resistance by reducing blood lipids as well as oxidative stress and elevating insulin sensitivity on diabetic mice, which is in accord with results in the insulin resistance model of HepG2 cells. Mechanically, acyclovir stimulates pyruvate kinase M1 (PKM1) directly to activate adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/Sirtuin1 (SIRT1) signaling pathway, thus improving insulin resistance.
SIGNIFICANCE: The present study supports that acyclovir should be translated to remedy DM, and PKM1 might be a valuable target to develop new medicines.

Keywords:  AMPK/SIRT1; Acyclovir; DM; Insulin resistance; PKM1

DOI:  https://doi.org/10.1016/j.lfs.2022.120725
Food Nutr Res. 2022 ;66

Citrus maxima and tea regulate AMPK signaling pathway to retard the progress of nonalcoholic fatty liver disease.

Shuai Wen, Ran An, Zhi-Gang Li, Zhao-Xiang Lai, Dong-Li Li, Jun-Xi Cao, Ruo-Hong Chen, Wen-Ji Zhang, Qiu-Hua Li, Xing-Fei Lai, Shi-Li Sun, Ling-Li Sun.

  Background: Nonalcoholic fatty liver disease (NAFLD) is a chronic metabolic disease that easily induces hepatitis, cirrhosis, and even liver cancer. The long-term use of NAFLD therapeutic drugs produces toxicity and drug resistance. Therefore, it is necessary to develop high efficiency and low-toxicity active ingredients to alleviate NAFLD.Objective: This study aimed to reveal the role and mechanism of a new functional food CMT in alleviating NAFLD.
Results: In the ob/ob fatty liver mice models, the CMT extracts significantly inhibited the weight gain of the mice and reduced the accumulation of white fat. The anatomical and pathological results showed that CMT relieved fatty liver in mice and reduced excessive lipid deposition and inflammatory infiltration. Serological and liver biochemical indicators suggest that CMT reduced dyslipidemia and liver damage caused by fatty liver. CMT obviously activated the adenosine 5'-monophosphate-activated protein kinase (AMPK)/acetyl-coA carboxylase (ACC) and AMPK/fatty acid synthase (FAS) signaling pathways, promoted fat oxidation, and inhibited synthesis. Moreover, CMT regulated the expression of inflammatory factors to relieve hepatitis caused by NAFLD.
Conclusion: The study explained the role and mechanism of CMT in alleviating NAFLD and suggested that the active ingredients of CMT might be beneficial in NAFLD therapy.

Keywords:  AMPK; Citrus maxima; nonalcoholic fatty liver disease; tea

DOI:  https://doi.org/10.29219/fnr.v66.7652
JCI Insight. 2022 Jun 28. pii: e155010. [Epub ahead of print]

Glycocalyx heparan sulfate cleavage promotes endothelial cell angiopoietin-2 expression by impairing shear stress-related AMPK/FoxO1 signaling.

Robert P Richter, Amit R Ashtekar, Lei Zheng, Danielle Pretorius, Tripathi Kaushlendra, Ralph D Sanderson, Amit Gaggar, Jillian R Richter.

  Angiopoietin-2 (Ang-2) is a key mediator of vascular disease during sepsis, and elevated plasma levels of Ang-2 are associated with organ injury scores and poor clinical outcomes. We have previously observed that biomarkers of endothelial glycocalyx (EG) damage correlate with plasma Ang-2 levels, suggesting a potential mechanistic linkage between EG injury and Ang-2 expression during states of systemic inflammation. However, the cell signaling mechanisms regulating Ang-2 expression following EG damage are unknown. In the current study, we determined the temporal associations between plasma heparan sulfate (HS) levels as a marker of EG erosion and plasma Ang-2 levels in children with sepsis and in mouse models of sepsis. Secondly, we evaluated the role of shear stress-mediated 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling in Ang-2 expression following enzymatic HS cleavage from the surface of human primary lung microvascular endothelial cells (HLMVEC). We found that plasma HS levels peak prior to plasma Ang-2 levels in children and mice with sepsis. Further, we discovered that impaired AMPK signaling contributes to increased Ang-2 expression following HS cleavage from flow conditioned HLMVECs, establishing a novel paradigm by which Ang-2 may be upregulated during sepsis.

Keywords:  Endothelial cells; Glycobiology; Proteases; Vascular Biology

DOI:  https://doi.org/10.1172/jci.insight.155010
J Chem Neuroanat. 2022 Jun 27. pii: S0891-0618(22)00062-X. [Epub ahead of print] 102132

Single-Cell Multiplex qPCR Evidence for Sex-Dimorphic Glutamate Decarboxylase, Estrogen Receptor, and 5'-AMP-Activated Protein Kinase Alpha Subunit mRNA Expression by Ventromedial Hypothalamic Nucleus GABAergic Neurons.

Md Haider Ali, Ayed A Alshamrani, Prabhat R Napit, Karen P Briski.

  The inhibitory amino acid transmitter γ-aminobutryic acid (GABA) acts within the ventromedial hypothalamus to regulate systemic glucose homeostasis, but the issue of whether this neurochemical signal originates locally or is supplied by afferent innervation remains controversial. Here, combinatory in situ immunocytochemistry/laser-catapult microdissection/single-cell multiplex qPCR techniques were used to investigate the premise that ventromedial hypothalamic nucleus ventrolateral (VMNvl) and/or dorsomedial (VMNdm) division neurons contain mRNAs encoding glutamate decarboxylase (GAD)65 or GAD67 and metabolic-sensory biomarkers, and that expression of these genes is sex-dimorphic. In male and female rats, GAD65 mRNA was elevated in VMNvl versus VMNdm GAD65/67-immunopositive (-ir) neurons, yet the female exhibited higher GAD67 transcript content in VMNdm versus VMNvl GABAergic nerve cells. Estrogen receptor (ER)-alpha transcripts were lower in female versus male GABA neurons from either VMN division; ER-beta and G-protein-coupled ER-1 mRNA expression was also comparatively reduced in cells from female versus male VMNvl. VMNvl and VMNdm GAD65/67-ir-positive neurons showed equivalent levels of glucokinase and sulfonylurea receptor-1 mRNA between sexes. 5'-AMP-activated protein kinase-alpha 1 (AMPKα1) and -alpha 2 (AMPKα2) transcripts were lower in female versus male VMNdm GABAergic neurons, yet AMPKα2 mRNA levels were higher in cells acquired from female versus male VMNvl. Current studies document GAD65 and -67 gene expression in VMNvl and VMNdm GAD65/67-ir-positive neurons in each sex. Results infer that GABAergic neurons in each division may exhibit sex differences in receptiveness to estradiol. Outcomes also support the prospect that energy sensory function by this neurotransmitter cell type may predominate in the VMNvl in female versus VMNdm in the male.

Keywords:  AMPK, glucokinase regulatory protein, estrogen receptor-alpha; G-protein-coupled estrogen receptor-1; glutamate decarboxylase; ventromedial hypothalamic nucleus

DOI:  https://doi.org/10.1016/j.jchemneu.2022.102132
Aging (Albany NY). 2022 Jun 27. 14(undefined):

Galectin-3 induces vascular smooth muscle cells calcification via AMPK/TXNIP pathway.

Lei Tian, Yong Wang, Ruiyan Zhang.

  Galectin-3 plays an important role in atherosclerosis. Upregulation of VSMCs calcification is involved in the progression and development of vulnerable plaques. Thioredoxin-interacting protein (TXNIP) has been regarded as an important determinant in regulating inflammation and oxidative stress. In this study, we evaluated the role of TXNIP in galectin-3-induced vascular calcification. A primary culture of mouse VSMCs was established by enzymatic digestion of aorta. Small interfering (si) RNA was used to knock down the expression of target gene. VSMCs were treated with 3-methyladenine (3-MA) or compound C respectively. Western blot was performed to detect the protein level in VSMCs, Alkaline phosphatase (ALP) and Alizarin red staining was used to observe calcium deposition. Dihydroethidium (DHE) staining was used to observe the reactive oxygen species (ROS) production. Here we showed that galectin-3 increased aorta and VSMCs calcification, which was associated with AMPK/TXNIP upregulation and autophagy activation. TXNIP inhibition decreased galectin-3-induced aorta and VSMCs calcification and autophagy activation. 3-MA or Atg5 siRNA decreased galectin-3-induced upregulation of Runx2, BMP2 and OPN. AMPK mediated galectin-3-induced VSMCs osteogenic differentiation. These findings illustrated that TXNIP mediated galectin-3-induced vascular calcification, AMPK and autophagy activation were also associated with this process.

Keywords:  TXNIP; VSMCs; calcification; galectin-3

DOI:  https://doi.org/10.18632/aging.204130
Front Aging Neurosci. 2022 ;14 890823

PINK1/Parkin Pathway Activation for Mitochondrial Quality Control - Which Is the Best Molecular Target for Therapy?

Laura F Silvian.

  There has been long-term interest in drugging the PINK1-Parkin pathway with therapeutics as a treatment for Parkinson's disease (PD). Despite significant structural data on Parkin as well as the PINK1 kinase and the multiple conformational changes it undergoes, activation of these targets is non-trivial. This review highlights small molecule screening results that suggests that activation of Parkin biochemically does not necessarily translate to activation of Parkin within cells. There are also issues with activation of PINK1 with kinetin analogs, which do not appear to rescue rodent models of PD. The counter-measure of activating the mitophagy pathway with deubiquitinase (DUB) inhibitors such as USP30 inhibitors is progressing in the clinic for kidney disease and the proof of biology for this target will be tested in these trials. An alternative mechanism of activating Parkin in response to oxidative stress via Parkin phosphorylation by the AMPK-ULK1 pathway may be a simpler way to lower the energy barrier Parkin activation.

Keywords:  AMPK; PINK1-Parkin pathway; Parkinson’s disease; ULK1 (unc-51 like autophagy activating kinase 1); cryoEM (cryo-electron microscopy); crystallography; molecular mechanisms of activation; small molecule

DOI:  https://doi.org/10.3389/fnagi.2022.890823
Exp Ther Med. 2022 Jul;24(1): 485

Salvianolic acid A promotes mitochondrial biogenesis and function via regulating the AMPK/PGC-1α signaling pathway in HUVECs.

Xuelian Wang, Mi Zhang, Mengyao Zhang, Yantao Han, Xuehong Chen, Wenwen Zhao, Zhiwu Han, Jialin Sun.

  Mitochondrial dysregulation is an important pathology that leads to endothelial dysfunction, and the occurrence and development of cardiovascular diseases. Salvianolic acid A (SAA) has been demonstrated to be effective in the treatment of vascular complications of type 2 diabetes mellitus. Limited information has been reported on the effects of SAA on mitochondrial function in endothelial cells. In the present study, the effects of SAA on mitochondrial biogenesis and the related underlying mechanisms were investigated in human umbilical vein endothelial cells (HUVECs). Mitotracker red staining and transmission electron microscopy were used to evaluate the effect of SAA on mitochondrial quality. The effect of SAA treatment on mitochondrial DNA/nuclear DNA ratio of HUVECs was detected by real-time quantitative PCR. Western blot was used to determine the protein expression levels of complex III and Complex IV of mitochondrial oxidative phosphorylation subunit, and ATP production was determined by ATP test kit. Real-time quantitative PCR and Western blot were used to determine the effects of SAA on the expression of peroxisome proliferator-activated receptor γ coactivator (PGC-1α) and its target genes nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM) proteins and genes. Finally, in the presence of 5'AMP-activated protein kinase (AMPK) specific inhibitors, the expression of PGC-1α, NRF1 and TFAM proteins and the phosphorylation levels of AMPK and Acetyl CoA Carboxylase (ACC) were detected by Western blot or real-time quantitative PCR. The results showed that SAA treatment significantly promoted mitochondrial biogenesis and enhanced mitochondrial function of HUVECs. SAA significantly increased the expression levels of PGC-1α and its target genes NRF1 and (TFAM), a key regulator of mitochondrial biogenesis in HUVECs. These enhancements were accompanied by significantly increased phosphorylation of AMPK and ACC, and were significantly inhibited by specific AMPK inhibitors. These results suggest that SAA may promote mitochondrial biogenesis in endothelial cells by activating the AMPK-mediated PGC-1α/TFAM signaling pathway. These data provide new insights into the mechanism of action of SAA in treating diabetic vascular complications.

Keywords:  5'AMP-activated protein kinase; diabetic vascular complications; mitochondrial biogenesis; peroxisome proliferator-activated receptor γ coactivator 1-α/mitochondrial transcription factor A; salvianolic acid A

DOI:  https://doi.org/10.3892/etm.2022.11412
Int J Endocrinol. 2022 ;2022 2658727

TET3 Mediates 5hmC Level and Promotes Tumorigenesis by Activating AMPK Pathway in Papillary Thyroid Cancer.

Jiadong Chi, Wei Zhang, Yigong Li, Jie Zhao, Xiangqian Zheng, Ming Gao.

Thyroid cancer is the most common endocrine malignant tumor. The accurate risk stratification and prognosis assessment is particularly important for patients with thyroid cancer, which can reduce the tumor recurrence rate, morbidity, and mortality effectively. DNA methylation is one of the most widely studied epigenetic modifications. Many studies have shown that 5hmC-mediated demethylation played an important role in tumors. The hydroxylation of 5mC is catalyzed by ten-eleven translocation dioxygenase (TET). In this study, we first found that the abnormal expression of 5hmC was closely related to microcarcinoma, multifocal, extraglandular invasion and lymph node metastasis of thyroid carcinoma. Then, we identified TET3 was differentially expressed in thyroid cancers and normal tissues from the TET family. TET3 can promote the proliferation, migration, and invasion of thyroid cancer. TET3-mediated 5hmC can regulate the transcription of AMPK pathway-related genes to activate the AMPK pathway and autophagy and therefore promote PTC proliferation. These findings provide a preclinical rationale for the design of novel therapeutic strategies for this target to improve the clinical outcome of patients with PTC.

DOI: https://doi.org/10.1155/2022/2658727
Food Res Int. 2022 Jul;pii: S0963-9969(22)00311-8. [Epub ahead of print]157 111254

Phosphoproteomics reveals that camel and goat milk improve glucose homeostasis in HDF/STZ-induced diabetic rats through activation of hepatic AMPK and GSK3-GYS axis.

Binsong Han, Lina Zhang, Yanmei Hou, Jinjing Zhong, Kasper Hettinga, Peng Zhou.

  Diabetes is a serious public health problem with global implications. Among many diabetes management therapies, non-pharmacological therapies such as those that focus on diet and exercise are gradually becoming more acceptable to patients. Within dietary management options, dairy products such as camel and goat milk are valued for their specific health benefits. The aim of this study was therefore to investigate the effect of camel and goat milk consumption on glucose homeostasis in high-fat diet and streptozotocin (HFD/STZ) induced diabetic rats. HFD/STZ-induced diabetic rats were fed with different milk for 35 days. Parameters related to glucose homeostasis, as well as hepatic proteome and phosphoproteome were investigated. The results of which showed that camel and goat milk consumption improved fasting glucose levels, glucose tolerance, and indicators related to lipid metabolism, while bovine and sheep milk consumption did not work. In addition, the hepatic phosphoproteome suggests that the ameliorative effect of both camel and goat milk was associated with the activation of AMPK. However, camel milk consumption further elevated the phosphorylation level of hepatic ACC, while goat milk consumption activated GSK3-GYS axis-related proteins. The present study investigated the possible mechanisms by which camel and goat milk consumption improves glucose homeostasis in HFD/STZ-induced diabetic rats and revealed their differences in the mechanism of antidiabetic effect.

Keywords:  AMPK; Camel milk; Diabetes; GSK3-GYS; Goat milk; Phosphoproteome

DOI:  https://doi.org/10.1016/j.foodres.2022.111254
Front Pharmacol. 2021 ;12 777670

Zhen-Wu-Tang Induced Mitophagy to Protect Mitochondrial Function in Chronic Glomerulonephritis via PI3K/AKT/mTOR and AMPK Pathways.

Bihao Liu, Yiwen Cao, Dejuan Wang, Yuan Zhou, Peichun Zhang, Junbiao Wu, Junqi Chen, Jianguang Qiu, Jiuyao Zhou.

  Chronic glomerulonephritis (CGN) is one of the major causes of end-stage kidney disease. Zhen-wu-tang (ZWT), as a famous Chinese herbal prescription, is widely used in China for CGN therapy in clinic. However, the mechanism of ZWT in CGN has not been fully understood. The present study explored the therapeutic effect and the underlying mechanism of ZWT on mitochondrial function in cationic bovine serum albumin (C-BSA)-induced CGN model rats and tumor necrosis factor (TNF-α)-damaged mouse podocytes. The renal functions were measured by serum creatinine (Scr) and blood urea nitrogen (BUN). Renal pathological changes and ultrastructure of kidney tissues were evaluated by periodic acid-Schiff (PAS) staining and transmission electron microscopy. The levels of antioxidases, including mitochondrial catalase (CAT), superoxide dismutase 2 (SOD2), and peroxiredoxin 3 (PRDX3), in CGN rats were examined by real-time PCR. The mitochondrial functions of podocytes were measured by ATP concentration, mitochondrial membrane potential (MMP), and mitochondrial ROS (mtROS). For mitophagy level detection, the expressions of mitophagy-related proteins, including LC3, p62, heat shock protein 60 (HSP60), and translocase of outer mitochondrial membrane 20 (TOMM20), were measured by Western blot, as the colocation of LC3 and mitochondrial marker COX IV were evaluated by immunofluorescence. Our results manifested that ZWT ameliorated CGN model rats by a remarkable decrease in Scr and BUN, inhibition of mesangial matrix proliferation, protection against foot processes fusion, and basement membrane thickening. More importantly, ZWT protected against mitochondrial dysfunction by increasing the expressions of CAT, SOD2, and PRDX3 in CGN model rats, increased ATP content and MMP in podocytes, and decreased excessive mtROS. Furthermore, ZWT induced mitophagy in CGN through increasing the expression of LC3, and decreasing p62, HSP60, TOMM20, and ZWT also enhanced the colocation of LC3 to the mitochondria. We found that ZWT inhibited the PI3K/AKT/mTOR pathway, which could be disturbed by PI3K inhibitor LY294002 and agonist insulin-like growth factor 1. Moreover, ZWT reversed the inhibition of the AMPK pathway in CGN. Overall, ZWT ameliorated renal mitochondrial dysfunction probably by inducing mitophagy via the PI3K/AKT/mTOR and AMPK pathways.

Keywords:  AMPK pathway; PI3K/Akt/mTOR pathway; Zhen-wu-tang; chronic glomerulonephritis; mitochondrial function; mitophagy

DOI:  https://doi.org/10.3389/fphar.2021.777670
Cell Stress Chaperones. 2022 Jul 02.

Modulation of endoplasmic reticulum stress via sulforaphane-mediated AMPK upregulation against nonalcoholic fatty liver disease in rats.

Somaya Z Mansour, Enas M Moustafa, Fatma S M Moawed.

  Nonalcoholic fatty liver disease (NAFLD) is a major health concern. Endoplasmic reticulum (ER) stress, inflammation, and metabolic dysfunctions may be targeted to prevent the progress of nonalcoholic fatty liver disease. Sulforaphane (SFN), a sulfur-containing compound that is abundant in broccoli florets, seeds, and sprouts, has been reported to have beneficial effects on attenuating metabolic diseases. In light of this, the present study was designed to elucidate the mechanisms by which SFN ameliorated ER stress, inflammation, lipid metabolism, and insulin resistance - induced by a high-fat diet and ionizing radiation (IR) in rats. In our study, the rats were randomly divided into five groups: control, HFD, HFD + SFN, HFD + IR, and HFD + IR + SFN groups. After the last administration of SFN, liver and blood samples were taken. As a result, the lipid profile, liver enzymes, glucose, insulin, IL-1β, adipokines (leptin and resistin), and PI3K/AKT protein levels, as well as the mRNA gene expression of ER stress markers (IRE-1, sXBP-1, PERK, ATF4, and CHOP), fatty acid synthase (FAS), peroxisome proliferator-activated receptor-α (PPAR-α). Interestingly, SFN treatment modulated the levels of proinflammatory cytokine including IL-1β, metabolic indices (lipid profile, glucose, insulin, and adipokines), and ER stress markers in HFD and HFD + IR groups. SFN also increases the expression of PPAR-α and AMPK genes in the livers of HFD and HFD + IR groups. Meanwhile, the gene expression of FAS and CHOP was significantly attenuated in the SFN-treated groups. Our results clearly show that SFN inhibits liver toxicity induced by HFD and IR by ameliorating the ER stress events in the liver tissue through the upregulation of AMPK and PPAR-α accompanied by downregulation of FAS and CHOP gene expression.

Keywords:  AMPK; Endoplasmic reticulum stress; Ionizing radiation; NAFLD; PPAR-α; Sulforaphane

DOI:  https://doi.org/10.1007/s12192-022-01286-w
Front Pharmacol. 2022 ;13 894285

Methyl Gallate Suppresses the Migration, Invasion, and Epithelial-Mesenchymal Transition of Hepatocellular Carcinoma Cells via the AMPK/NF-κB Signaling Pathway in vitro and in vivo.

Huaguo Liang, Zexin Chen, Ruihui Yang, Qingsong Huang, Hongmei Chen, Wanting Chen, Li Zou, Peng Wei, Shijie Wei, Yongxia Yang, Yongli Zhang.

  Methyl gallate (MG), a polyphenolic compound found in plants, is widely used in traditional Chinese medicine. MG is known to alleviate several cancer symptoms. However, most studies that have reported the antitumor effects of MG have done so at the cellular level, and the inhibitory effect and therapeutic mechanism of MG in hepatocellular carcinoma (HCC) have not been extensively explored in vivo. We aimed to understand the therapeutic mechanism of MG in HCC in vitro and in vivo. MTT and colony formation assays were used to determine the impact of MG on the proliferation of a human HCC cell line, BEL-7402; wound healing and transwell assays were used to quantify the migration and invasion of HCC cells. Western blotting was used to quantify the expression of the AMPK/NF-κB signaling pathway proteins. In vivo tumor growth was measured in a xenograft tumor nude mouse model treated with MG, and hematoxylin-eosin staining and immunohistochemistry (IHC) were used to visualize the histological changes in the tumor tissue. We found that MG showed anti-proliferative effects both in vitro and in vivo. MG downregulated the protein expression of AMPK, NF-κB, p-NF-κB, and vimentin and upregulated the expression of E-cadherin in a dose-dependent manner. Additionally, MG inhibited the migration and invasion of HCC cells by decreasing MMP9 and MMP2 expression and increasing TIMP-2 expression. These were consistent with the results of IHC in vivo. MG inhibited the proliferation, migration, and invasion of HCC cells. This effect potentially involves the regulation of the AMPK/NF-κB pathway, which in turn impacts epithelial-mesenchymal transition and MMP expression.

Keywords:  AMPK; epithelial-mesenchymal transition; hepatocellular carcinoma; invasion; methyl gallate; migration

DOI:  https://doi.org/10.3389/fphar.2022.894285
Biomed Pharmacother. 2022 Jun 27. pii: S0753-3322(22)00706-5. [Epub ahead of print]153 113317

Stigmasterol attenuates inflammatory response of microglia via NF-κB and NLRP3 signaling by AMPK activation.

Fan Jie, Xuan Yang, Bowen Yang, Yan Liu, Lipeng Wu, Baiyi Lu.

  Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Although its pathogenesis remains unclear, studies have indicated microglia-mediated neuroinflammation playing an important role. Phytosterols are a class of natural compounds presented in food, and have anti-inflammatory abilities. Recent studies suggested that phytosterols can traverse the blood-brain barrier and enter the brain, however, it remains largely unknown that whether phytosterols affect neuroinflammation in the AD pathogenesis. Here, we used APPswe/PS1dE9 mice as the animal model of AD, and found that stigmasterol treatment attenuated cognitive deficits, and decreased Aβ42 concentration in cortex and hippocampus. Stigmasterol treatment also suppressed neuroinflammation, by reducing pro-inflammatory cytokine levels and microglia activation. Next, we simulated BV2 cells with Aβ42 oligomers, which induced inflammatory responses of microglia. Stigmasterol protected BV2 cells against Aβ42 oligomers induced inflammation, and mediated secretion of pro-inflammatory cytokines via NF-κB and NLRP3 signaling pathways by AMPK activation. Stigmasterol also alleviated the M1 polarization of BV2 cells. In general, our study demonstrates that stigmasterol ameliorated neuroinflammation in APP/PS1 mice, and suppressed inflammatory response of microglia to Aβ42 oligomers via AMPK/NF-κB and AMPK/NLRP3 signaling, which provides a mechanistic insight for stigmasterol in anti-inflammation and AD therapy.

Keywords:  Alzheimer’s disease; Microglia; Neuroinflammation; Stigmasterol

DOI:  https://doi.org/10.1016/j.biopha.2022.113317