bims-amsmem 2022-02-20 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–02–20
twenty-one papers selected by
Dipsikha Biswas, Københavns Universitet

An AMPKα2-specific phospho-switch controls lysosomal targeting for activation.
Glia fuel neurons with locally synthesized ketone bodies to sustain memory under starvation.
Metformin as a Potential Treatment Option for Endometriosis.
AMPK and Polycystic Kidney Disease Drug Development: An Interesting Off-Target Target.
Targeting Breast Cancer and Their Stem Cell Population through AMPK Activation: Novel Insights.
Punicalagin and Ketogenic Amino Acids Loaded Organic Lipid Carriers Enhance the Bioavailability, Mitochondrial β-Oxidation, and Ketogenesis in Maturing Adipocytes.
Sestrin2 overexpression attenuates osteoarthritis pain via induction of AMPK/PGC-1α-mediated mitochondrial biogenesis and suppression of neuroinflammation.
Insulin-like growth factor-1 inhibits apoptosis of rat gastric smooth muscle cells under high glucose condition via adenosine monophosphate-activated protein kinase (AMPK) pathway.
Cardiomyocyte stromal interaction molecule 1 is a key regulator of Ca2+ -dependent kinase and phosphatase activity in the mouse heart.
The Deubiquitinase OTUB1 Is a Key Regulator of Energy Metabolism.
Metformin attenuated sepsis-associated liver injury and inflammatory response in aged mice.
Metformin Ameliorates Inflammation and Airway Remodeling of Experimental Allergic Asthma in Mice by Restoring AMPKα Activity.
Fibronectin type III domain-containing 5 improves aging-related cardiac dysfunction in mice.
Adiponectin improves the therapeutic efficacy of mesenchymal stem cells by enhancing their engraftment and survival in the peri-infarct myocardium through the AMPK pathway.
Glycolipid Metabolism and Metagenomic Analysis of the Therapeutic Effect of a Phenolics-Rich Extract from Noni Fruit on Type 2 Diabetic Mice.
Ophiopogonin‑B targets PTP1B to inhibit the malignant progression of hepatocellular carcinoma by regulating the PI3K/AKT and AMPK signaling pathways.
Sesamol Reverses Myofiber-Type Conversion in Obese States via Activating the SIRT1/AMPK Signal Pathway.
Salidroside inhibits doxorubicin-induced cardiomyopathy by modulating a ferroptosis-dependent pathway.
Tofacitinib and metformin reduce the dermal thickness and fibrosis in mouse model of systemic sclerosis.
Multistability in Macrophage Activation Pathways and Metabolic Implications.
Quercetin Reduces Lipid Accumulation in a Cell Model of NAFLD by Inhibiting De Novo Fatty Acid Synthesis through the Acetyl-CoA Carboxylase 1/AMPK/PP2A Axis.

Cell Rep. 2022 02 15. pii: S2211-1247(22)00086-9. [Epub ahead of print]38(7): 110365

An AMPKα2-specific phospho-switch controls lysosomal targeting for activation.

Kaitlin R Morrison, William J Smiles, Naomi X Y Ling, Ashfaqul Hoque, Gabrielle Shea, Kevin R W Ngoei, Dingyi Yu, Lisa Murray-Segal, John W Scott, Sandra Galic, Bruce E Kemp, Janni Petersen, Jonathan S Oakhill.

  AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) are metabolic kinases that co-ordinate nutrient supply with cell growth. AMPK negatively regulates mTORC1, and mTORC1 reciprocally phosphorylates S345/7 in both AMPK α-isoforms. We report that genetic or torin1-induced loss of α2-S345 phosphorylation relieves suppression of AMPK signaling; however, the regulatory effect does not translate to α1-S347 in HEK293T or MEF cells. Dephosphorylation of α2-S345, but not α1-S347, transiently targets AMPK to lysosomes, a cellular site for activation by LKB1. By mass spectrometry, we find that α2-S345 is basally phosphorylated at 2.5-fold higher stoichiometry than α1-S347 in HEK293T cells and, unlike α1, phosphorylation is partially retained after prolonged mTORC1 inhibition. Loss of α2-S345 phosphorylation in endogenous AMPK fails to sustain growth of MEFs under amino acid starvation conditions. These findings uncover an α2-specific mechanism by which AMPK can be activated at lysosomes in the absence of changes in cellular energy.

Keywords:  AMPK; energy homeostasis; kinase; lysosome; mTORC1; metabolic signaling; phosphorylation

DOI:  https://doi.org/10.1016/j.celrep.2022.110365
Nat Metab. 2022 Feb 17.

Glia fuel neurons with locally synthesized ketone bodies to sustain memory under starvation.

Bryon Silva, Olivier L Mantha, Johann Schor, Alberto Pascual, Pierre-Yves Plaçais, Alice Pavlowsky, Thomas Preat.

During starvation, mammalian brains can adapt their metabolism, switching from glucose to alternative peripheral fuel sources. In the Drosophila starved brain, memory formation is subject to adaptative plasticity, but whether this adaptive plasticity relies on metabolic adaptation remains unclear. Here we show that during starvation, neurons of the fly olfactory memory centre import and use ketone bodies (KBs) as an energy substrate to sustain aversive memory formation. We identify local providers within the brain, the cortex glia, that use their own lipid store to synthesize KBs before exporting them to neurons via monocarboxylate transporters. Finally, we show that the master energy sensor AMP-activated protein kinase regulates both lipid mobilization and KB export in cortex glia. Our data provide a general schema of the metabolic interactions within the brain to support memory when glucose is scarce.

DOI: https://doi.org/10.1038/s42255-022-00528-6
Cancers (Basel). 2022 Jan 24. pii: 577. [Epub ahead of print]14(3):

Metformin as a Potential Treatment Option for Endometriosis.

Żaneta Kimber-Trojnar, Dominik Franciszek Dłuski, Magdalena Wierzchowska-Opoka, Monika Ruszała, Bożena Leszczyńska-Gorzelak.

  Endometriosis is a common disease in women of reproductive age, and its pathogenesis seems to be largely affected by hormone imbalance, inflammation, oxidative stress, and autophagy dysregulation. These pathophysiological disturbances interact with one another through mechanisms that are still awaiting elucidation. The aim of this article is to present current knowledge regarding the possibilities of using metformin in the pharmacological treatment of endometriosis. Metformin is an insulin sensitizer widely used for the treatment of type 2 diabetes mellitus. The pleiotropic effects of metformin are mainly exerted through the activation of AMP-activated protein kinase, which is the key cellular energy homeostasis regulator that inhibits mTOR, a major autophagy suppressor. Metformin regresses endometriotic implants by increasing the activity of superoxide dismutase. It is also an inhibitor of metalloproteinase-2, decreasing the levels of the vascular endothelial growth factor and matrix metalloproteinase-9 in animal studies. In endometriosis, metformin might modify the stroma-epithelium communication via Wnt2/β-catenin. With its unique therapeutic mechanisms and no serious side effects, metformin seems to be a helpful anti-inflammatory and anti-proliferative agent in the treatment of endometriosis. It could be a missing link for the successful treatment of this chronic disease.

Keywords:  endometriosis; inflammation; medical therapy; metformin

DOI:  https://doi.org/10.3390/cancers14030577
Front Med (Lausanne). 2022 ;9 753418

AMPK and Polycystic Kidney Disease Drug Development: An Interesting Off-Target Target.

Michael J Caplan.

  Autosomal Dominant Polycystic Kidney Disease is a genetic disease that causes dramatic perturbations of both renal tissue architecture and of a multitude of cellular signaling pathways. The relationship between the products of the genes whose mutations cause polycystic kidney disease and these signaling pathways remains difficult to determine. It is clear, however, that cellular metabolism is dramatically altered in cells that are affected by polycystic kidney disease mutations. Adenosine monophosphate-stimulated protein kinase is a master regulator of cellular energy use and generation pathways whose activity appears to be perturbed in cells affected by polycystic kidney disease. Furthermore, modulation of this enzyme's activity may constitute a promising approach for the development of new therapeutics for polycystic kidney disease.

Keywords:  Autosomal Dominant Polycystic Kidney Disease; CFTR; adenosine monophosphate-stimulated protein kinase; mTOR; metabolism; metformin

DOI:  https://doi.org/10.3389/fmed.2022.753418
Cells. 2022 Feb 07. pii: 576. [Epub ahead of print]11(3):

Targeting Breast Cancer and Their Stem Cell Population through AMPK Activation: Novel Insights.

Bhawna Uprety, Heidi Abrahamse.

  Despite some significant advancements, breast cancer has become the most prevalent cancer in the world. One of the main reasons for failure in treatment and metastasis has been attributed to the presence of cancer initiating cells-cancer stem cells. Consequently, research is now being focussed on targeting cancer cells along with their stem cell population. Non-oncology drugs are gaining increasing attention for their potent anticancer activities. Metformin, a drug commonly used to treat type 2 diabetes, is the best example in this regard. It exerts its therapeutic action by activating 5' adenosine monophosphate-activated protein kinase (AMPK). Activated AMPK subsequently phosphorylates and targets several cellular pathways involved in cell growth and proliferation and the maintenance of stem-like properties of cancer stem cells. Therefore, AMPK is emerging as a target of choice for developing effective anticancer drugs. Vanadium compounds are well-known PTP inhibitors and AMPK activators. They find extensive applications in treatment of diabetes and obesity via PTP1B inhibition and AMPK-mediated inhibition of adipogenesis. However, their role in targeting cancer stem cells has not been explored yet. This review is an attempt to establish the applications of insulin mimetic vanadium compounds for the treatment of breast cancer by AMPK activation and PTP1B inhibition pathways.

Keywords:  AMPK activation; cancer stem cells; non-oncology drugs; vanadium

DOI:  https://doi.org/10.3390/cells11030576
Nanomaterials (Basel). 2022 Jan 24. pii: 368. [Epub ahead of print]12(3):

Punicalagin and Ketogenic Amino Acids Loaded Organic Lipid Carriers Enhance the Bioavailability, Mitochondrial β-Oxidation, and Ketogenesis in Maturing Adipocytes.

Pandurangan Subash-Babu, Nouf Al-Numair, Tahani Almuzaini, Jegan Athinarayanan, Ali Abdullah Alshatwi.

  The identification of lipolytic bioactive compounds via the functional stimulation of carbohydrate response element-binding protein-1 (CREBp-1) and AMP-activated protein kinase (AMPK) is most warranted. Nano lipid carriers (NLCs) are currently being considered within drug delivery development as they facilitate controlled drug release and have intracellular bioavailability after encapsulating the active principles with lipid matrix. The present study has been designed to synthesize punicalagin, and ketogenic amino acids (KAA) loaded with organic lipid carriers to optimize the liposome-assisted intracellular delivery's bioavailability. Punicalagin (PUNI) and KAA (tryptophan, methionine, threonine, lysine, and leucine) were encapsulated with chia seed phospholipids by homogenization, emulsification, and cold ultra-sonication method to obtain nano lipid carriers (NLC). The physicochemical characterization of NLCs has been carried out using Zetasizer, FT-IR, and TEM analysis. Punicalagin and ketogenic amino acid-loaded NLCs (NLC-PUNI-KAA) were identified with an average diameter of 240 to 800 nm. The biosafety of NLC-PUNI-KAA has been evaluated in human mesenchymal stem cells. PI staining confirmed that a 0.4, 0.8 or 1.6μg/dL dose of NLC-PUNI-KAA potentially maintains nuclear integration. NLC-PUNI-KAA treated with maturing adipocytes decreased lipid accumulation and significantly increased the gene expression levels of fatty acid beta-oxidation (PPARγC1α, UCP-1 and PRDM-16) pathways when compared to free PUNI (5 μg/dL) treatment. The lipolytic potential has been confirmed by the functional activation of AMPK and CREBp-1 protein levels. In conclusion, NLC-PUNI-KAA treatment effectively increased mitochondrial efficiency more than free punicalagin or orlistat treated maturing adipocyte. Enhanced lipolysis and decreased hypertrophic adipocyte resulted in decreased adipokine secretion, which has been associated with the suppression of obesity-associated comorbidities and vascular cell inflammation. The bioefficacy and lipolytic potential of water-soluble punicalagin have been improved after functional modification into NLCs.

Keywords:  NLCs; chia seed; fatty acid oxidation; ketogenesis; mitochondrial; punicalagin

DOI:  https://doi.org/10.3390/nano12030368
Brain Behav Immun. 2022 Feb 10. pii: S0889-1591(22)00041-1. [Epub ahead of print]102 53-70

Sestrin2 overexpression attenuates osteoarthritis pain via induction of AMPK/PGC-1α-mediated mitochondrial biogenesis and suppression of neuroinflammation.

Jia Sun, Fan-He Song, Jia-Yi Wu, Long-Qing Zhang, Dan-Yang Li, Shao-Jie Gao, Dai-Qiang Liu, Ya-Qun Zhou, Wei Mei.

   BACKGROUND: Our previous study indicated that reactive oxygen species (ROS) are critically involved in chronic pain. Sestrin2 (Sesn2), a novel stress-inducible protein, is evidenced to reduce the generation of ROS. The study examined the role of Sesn2 in osteoarthritis (OA) pain and delineated the underlying molecular mechanisms.
METHODS: In the present study, we investigated the impact of Sesn2 on mitochondrial biogenesis in a rat model of OA pain. After adeno-associated viral (AAV)-Sesn2EGFP was injected for 14 days, OA was induced by intra-articular injection of monosodium iodoacetate (MIA). We assessed pain behaviors (weight-bearing asymmetry and paw withdrawal threshold) and explored possible mechanisms in the L4-6 spinal cord.
RESULTS: Our results showed that overexpression of Sesn2 in the spinal cord alleviated pain behaviors in OA rats. Moreover, overexpression of Sesn2 increased the activity of AMP-activated protein kinase (AMPK) signaling and significantly restored mitochondrial biogenesis. Besides, Sesn2 overexpression inhibited the activation of astrocytes and microglia, and decreased the production of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the spinal cord of the OA pain rats. These effects were significantly reversed by an AMPK inhibitor.
CONCLUSIONS: Collectively, these results suggest that Sesn2 overexpression ameliorates mechanical allodynia and weight-bearing asymmetry in OA rats via activation of AMPK/PGC-1α-mediated mitochondrial biogenesis in the spinal cord. Moreover, Sesn2 overexpression attenuates OA-induced neuroinflammation at least partly by activating AMPK signaling. Sesn2 may become an encouraging therapeutic strategy for OA pain relief and other disorders.

Keywords:  AMPK; Mitochondrial biogenesis; Neuroinflammation; Osteoarthritis pain; Sestrin2

DOI:  https://doi.org/10.1016/j.bbi.2022.02.015
Folia Histochem Cytobiol. 2022 Feb 14.

Insulin-like growth factor-1 inhibits apoptosis of rat gastric smooth muscle cells under high glucose condition via adenosine monophosphate-activated protein kinase (AMPK) pathway.

Xiang-Zi Zhang, Yan Sun, Mo-Han Zhang, Zheng Jin.

   INTRODUCTION: Diabetic gastroparesis (DGP) is a common chronic complication of diabetes characterized by decreased gastric motility, and an effective number of gastric smooth muscle cells (GSMCs) ensures gastric motility. A previous study documented that apoptosis was present in gastric smooth muscles in rats with DGP and adenosine monophosphate-activated protein kinase (AMPK) was an important factor of apoptosis of rat GSMCs cultured under high glucose conditions. This study aimed to explore the effect of insulin-like growth factor-1 (IGF-1) on apoptosis of high glucose cultured rat GSMCs after silencing of AMPK and elucidate the underlying mechanism.
MATERIAL AND METHODS: A total of 120 rats were divided into normal control (NC, n = 20), diabetic gastroparesis (DGP, n = 50) and DGP + IGF-1 (n = 50) groups. After establishing the rat model of DGP, rats in the DGP+IGF-1 group received an intraperitoneal injection of IGF-1 at a dose of 1.5 μg/kg/d for 10 weeks. The level of AMPK activity, liver kinase B1 (LKB1) activity, and calcium/calmodulin-dependent protein kinase β (CaMKKβ) expression in rat gastric smooth muscle tissues was detected by Western blot analysis. Apoptosis in rat gastric smooth muscle tissues was detected by TUNEL assay. We also cultured rat GSMCs in vitro under high glucose (HG) condition (35 mM), incubated cells with IGF-1, and silenced AMPK with siRNA. The cells were divided into HG, HG + IGF-1, HG + siRNA, and HG + siRNA + IGF-1 groups. The apoptosis rates of rat GSMCs after silencing AMPK were detected by TUNEL assay and flow cytometry, and apoptosis-related protein expression in rat GSMCs was detected by Western blot.
RESULTS: IGF-1 decreased LKB1 activity, CaMKKβ expression, AMPK activity, and inhibited apoptosis in rat gastric smooth muscle tissues. Compared with rat GSMCs cultured in vitro under HG conditions, apoptosis rates were reduced after treatment with IGF-1 and AMPK silencing (both p < 0.01). Apoptosis rates were higher in the HG + siRNA group compared with the HG + IGF-1 group (p < 0.05). IGF-1 down-regulated the expression of calcium/calmodulin-dependent kinase II (CaMKII) and p53, up-regulated the expression of p21, PLC-β₃, PI3K p110 Ser¹⁰⁷⁰, and the activities of Akt, p70S6K, mTORC1, and mTORC2. IGF-1 also up-regulated Bcl-2 expression and down-regulated the expression of BAX and Caspase-3.
CONCLUSIONS: IGF-1 can inhibit the apoptosis of rat GSMCs under high glucose conditions, its mechanism may be related to the regulation of expression and activity of p53, PI3K, TSC-2, Akt, mTOR, 4E-BP1, p70S6K, p21, CaMKⅡ, and PLC-β3 in rat GSMCs acting through AMPK pathway.

Keywords:  AMPK signaling; IGF-1; apoptosis; gastric smooth muscle cells; high glucose; rat; siRNA

DOI:  https://doi.org/10.5603/FHC.a2022.0005
Physiol Rep. 2022 Feb;10(4): e15177

Cardiomyocyte stromal interaction molecule 1 is a key regulator of Ca2+ -dependent kinase and phosphatase activity in the mouse heart.

Helen E Collins, Joshua C Anderson, Adam R Wende, John C Chatham.

  Stromal interaction molecule 1 (STIM1) is a major regulator of store-operated calcium entry in non-excitable cells. Recent studies have suggested that STIM1 plays a role in pathological hypertrophy; however, the physiological role of STIM1 in the heart is not well understood. We have shown that mice with a cardiomyocyte deletion of STIM1 (cr STIM1-/- ) develop ER stress, mitochondrial, and metabolic abnormalities, and dilated cardiomyopathy. However, the specific signaling pathways and kinases regulated by STIM1 are largely unknown. Therefore, we used a discovery-based kinomics approach to identify kinases differentially regulated by STIM1. Twelve-week male control and cr STIM1-/- mice were injected with saline or phenylephrine (PE, 15 mg/kg, s.c, 15 min), and hearts obtained for analysis of the Serine/threonine kinome. Primary analysis was performed using BioNavigator 6.0 (PamGene), using scoring from the Kinexus PhosphoNET database and GeneGo network modeling, and confirmed using standard immunoblotting. Kinomics revealed significantly lower PKG and protein kinase C (PKC) signaling in the hearts of the cr STIM1-/- in comparison to control hearts, confirmed by immunoblotting for the calcium-dependent PKC isoform PKCα and its downstream target MARCKS. Similar reductions in cr STIM1-/- hearts were found for the kinases: MEK1/2, AMPK, and PDPK1, and in the activity of the Ca2+ -dependent phosphatase, calcineurin. Electrocardiogram analysis also revealed that cr STIM1-/- mice have significantly lower HR and prolonged QT interval. In conclusion, we have shown several calcium-dependent kinases and phosphatases are regulated by STIM1 in the adult mouse heart. This has important implications in understanding how STIM1 contributes to the regulation of cardiac physiology and pathophysiology.

Keywords:  calcium-dependent; cardiomyocytes; kinases; protein kinase C (PKC); protein kinase G (PKG); store-operated calcium entry (SOCE); stromal interaction molecule 1 (STIM1)

DOI:  https://doi.org/10.14814/phy2.15177
Int J Mol Sci. 2022 Jan 28. pii: 1536. [Epub ahead of print]23(3):

The Deubiquitinase OTUB1 Is a Key Regulator of Energy Metabolism.

Amalia Ruiz-Serrano, Christina N Boyle, Josep M Monné Rodríguez, Julia Günter, Agnieszka E Jucht, Svende Pfundstein, Andreas M Bapst, Thomas A Lutz, Roland H Wenger, Carsten C Scholz.

  Dysregulated energy metabolism is a major contributor to a multitude of pathologies, including obesity and diabetes. Understanding the regulation of metabolic homeostasis is of utmost importance for the identification of therapeutic targets for the treatment of metabolically driven diseases. We previously identified the deubiquitinase OTUB1 as substrate for the cellular oxygen sensor factor-inhibiting HIF (FIH) with regulatory effects on cellular energy metabolism, but the physiological relevance of OTUB1 is unclear. Here, we report that the induced global deletion of OTUB1 in adult mice (Otub1 iKO) elevated energy expenditure, reduced age-dependent body weight gain, facilitated blood glucose clearance and lowered basal plasma insulin levels. The respiratory exchange ratio was maintained, indicating an unaltered nutrient oxidation. In addition, Otub1 deletion in cells enhanced AKT activity, leading to a larger cell size, higher ATP levels and reduced AMPK phosphorylation. AKT is an integral part of insulin-mediated signaling and Otub1 iKO mice presented with increased AKT phosphorylation following acute insulin administration combined with insulin hypersensitivity. We conclude that OTUB1 is an important regulator of metabolic homeostasis.

Keywords:  FIH; Hif1an; deubiquitinating enzyme; energy expenditure; hypoxia; insulin; liver; ubiquitin system

DOI:  https://doi.org/10.3390/ijms23031536
Bioengineered. 2022 02;13(2): 4598-4609

Metformin attenuated sepsis-associated liver injury and inflammatory response in aged mice.

Heng Song, Xiaojuan Zhang, Ruiqing Zhai, Huoyan Liang, Gaofei Song, Yangyang Yuan, Yanan Xu, Yan Yan, Lingxiao Qiu, Tongwen Sun.

  Sepsis-associated liver injury is with poor survival in intensive care units. Metformin is well known for its therapeutic effects; however, its impact on treating liver injury due to sepsis remains poorly understood. This study investigated the therapeutic effects of metformin on aged mice suffering from sepsis-associated liver injury. Male C57BL/6 J mice aged (18-19 months) were divided into 3 groups: 1) intraperitoneal injection of sterile normal saline (C group), 12.5 mg/kg lipopolysaccharide (LPS) to induce sepsis-associated liver injury (LPS group), and 25 mg/kg metformin (MET) at 1 h after LPS injection (MET group). After 24 h, blood samples and liver tissue were collected for biochemical analysis. Histological assays revealed significantly elevated inflammatory infiltration and apoptosis in the liver, while metformin was found to relieve these aberrant features. The percentage of apoptotic cells decreased after metformin treatment (P < 0.05). Additionally, MET group had significantly reduced plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels compared to the LPS group (P < 0.05). Furthermore, in the MET group, the mRNA levels of chemokines and inflammatory factors, TNF-α, IL-6, caspase-1, decreased markedly (P < 0.05). Metformin notably reversed the decreased phosphorylated AMP-activated protein kinase (p-AMPK) and PGC-1α expressions in the liver of septic rats. Metformin also inhibited PDK1, HIF-1α expression, including downstream inflammatory mediators, HMGB1 and TNF-α. Metformin attenuated inflammation and liver injury in septic aged mice. Most importantly, we report the effect of metformin on liver injury via the AMPK-PGC1α axis in septic aged mice for the first time.

Keywords:  Metformin; aged mice; inflammatory response; lipopolysaccharide; sepsis-associated liver injury

DOI:  https://doi.org/10.1080/21655979.2022.2036305
Front Pharmacol. 2022 ;13 780148

Metformin Ameliorates Inflammation and Airway Remodeling of Experimental Allergic Asthma in Mice by Restoring AMPKα Activity.

Wenxian Ma, Qiaoyan Jin, Haiqin Guo, Xinpeng Han, Lingbin Xu, Shemin Lu, Changgui Wu.

  Metformin has been involved in modulating inflammatory state and inhibiting cell proliferation and angiogenesis. This study aimed to determine whether metformin alleviates airway inflammation and remodeling of experimental allergic asthma and elucidate the underlying mechanism. We sensitized and challenged mice with ovalbumin (OVA) to induce allergic asthma. During the challenge period, metformin was administered by intraperitoneal injection. By histopathological and immunohistochemical analyses, metformin-treated mice showed a significant alleviation in airway inflammation, and in the parameters of airway remodeling including goblet cell hyperplasia, collagen deposition and airway smooth muscle hypertrophy compared to those in the OVA-challenged mice. We also observed elevated levels of multiple cytokines (IL-4, IL-5, IL-13, TNF-α, TGF-β1 and MMP-9) in the bronchoalveolar lavage fluid, OVA-specific IgE in the serum and angiogenesis-related factors (VEGF, SDF-1 and CXCR4) in the plasma from asthmatic mice, while metformin reduced all these parameters. Additionally, the activity of 5'-adenosine monophosphate-activated protein kinase a (AMPKα) in the lungs from OVA-challenged mice was remarkably lower than control ones, while after metformin treatment, the ratio of p-AMPKα to AMPKα was upregulated and new blood vessels in the sub-epithelial area as evidenced by CD31 staining were effectively suppressed. These results indicate that metformin ameliorates airway inflammation and remodeling in an OVA-induced chronic asthmatic model and its protective role could be associated with the restoration of AMPKα activity and decreased asthma-related angiogenesis.

Keywords:  AMPK; airway inflammation; airway remodeling; asthma; metformin

DOI:  https://doi.org/10.3389/fphar.2022.780148
Aging Cell. 2022 Feb 15. e13556

Fibronectin type III domain-containing 5 improves aging-related cardiac dysfunction in mice.

Can Hu, Xin Zhang, Min Hu, Teng Teng, Yu-Pei Yuan, Peng Song, Chun-Yan Kong, Si-Chi Xu, Zhen-Guo Ma, Qi-Zhu Tang.

  Aging is an important risk factor for cardiovascular diseases, and aging-related cardiac dysfunction serves as a major determinant of morbidity and mortality in elderly populations. Our previous study has identified fibronectin type III domain-containing 5 (FNDC5) and its cleaved form, irisin, as the cardioprotectant against doxorubicin-induced cardiomyopathy. Herein, aging or matched young mice were overexpressed with FNDC5 by adeno-associated virus serotype 9 (AAV9) vectors, or subcutaneously infused with irisin to uncover the role of FNDC5 in aging-related cardiac dysfunction. To verify the involvement of nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) and AMP-activated protein kinase α (AMPKα), Nlrp3 or Ampkα2 global knockout mice were used. Besides, young mice were injected with AAV9-FNDC5 and maintained for 12 months to determine the preventive effect of FNDC5. Moreover, neonatal rat cardiomyocytes were stimulated with tumor necrosis factor-α (TNF-α) to examine the role of FNDC5 in vitro. We found that FNDC5 was downregulated in aging hearts. Cardiac-specific overexpression of FNDC5 or irisin infusion significantly suppressed NLRP3 inflammasome and cardiac inflammation, thereby attenuating aging-related cardiac remodeling and dysfunction. In addition, irisin treatment also inhibited cellular senescence in TNF-α-stimulated cardiomyocytes in vitro. Mechanistically, FNDC5 activated AMPKα through blocking the lysosomal degradation of glucagon-like peptide-1 receptor. More importantly, FNDC5 gene transfer in early life could delay the onset of cardiac dysfunction during aging process. We prove that FNDC5 improves aging-related cardiac dysfunction by activating AMPKα, and it might be a promising therapeutic target to support cardiovascular health in elderly populations.

Keywords:  AMPKα; FNDC5; aging-related cardiac dysfunction; inflammation

DOI:  https://doi.org/10.1111/acel.13556
Am J Transl Res. 2022 ;14(1): 534-553

Adiponectin improves the therapeutic efficacy of mesenchymal stem cells by enhancing their engraftment and survival in the peri-infarct myocardium through the AMPK pathway.

Xia-Qiu Tian, Xiao-Song Qian, Hong Wang, Yue-Jin Yang.

Poor viability of transplanted mesenchymal stem cells (MSCs) within the ischemic heart has limited their therapeutic potential for cardiac repair. We have previously shown that adiponectin (APN) treatment inhibits MSCs apoptosis under ischemic conditions in vitro. In this study, we investigated whether APN promoted the survival of MSCs in vivo and further contributed to cardiac repair in a rat model of acute myocardial infarction (AMI) by activating the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Rats were randomized into six groups: the sham, AMI control, and four other groups that were subjected to AMI followed by treatment with MSCs, APN, APN + MSCs, and APN + MSCs + AMPK inhibitor, respectively. The engraftment and survival of MSCs were detected using both immunofluorescence staining and qPCR. Cardiac function was assessed using echocardiography and left heart catheterization. H&E staining and immunohistochemical staining for MHC-II and CD206 were performed to assess the infiltration of inflammatory cells. Immunostaining for the smooth muscle cell marker α-smooth-muscle actin (α-SMA) and endothelial cell marker CD31 was performed to assess arteriogenesis and angiogenesis. APN treatment significantly enhanced the engraftment and survival rate of transplanted MSCs and further improved cardiac function and led to reduced infarct size compared with MSCs treatment alone at 4 weeks after AMI. Combined administration of APN and MSCs noticeably suppressed the inflammatory response by specifically promoting the shift of infiltrated macrophages to an less-inflammatory phenotype. Combined administration of APN and MSCs also significantly inhibited cardiomyocyte apoptosis and increased arteriogenesis and angiogenesis in the peri-infarct myocardium compared with MSCs transplantation alone. These protective effects of APN were associated with AMPK phosphorylation and were partially reversed by AMPK pathway inhibitors. Our results are the first to show that APN is able to effectively improve the survival and therapeutic efficacy of transplanted MSCs after AMI through AMPK activation. APN has the potential to be utilized for stem cell-based heart repair after AMI.

Keywords: AMPK; Mesenchymal stem cell; acute myocardial infarction; adiponectin
J Agric Food Chem. 2022 Feb 17.

Glycolipid Metabolism and Metagenomic Analysis of the Therapeutic Effect of a Phenolics-Rich Extract from Noni Fruit on Type 2 Diabetic Mice.

Ruimin Wang, Lin Zhang, Qingyang Zhang, Jiachao Zhang, Sixin Liu, Congfa Li, Lu Wang.

  The phenolics of noni fruit possess antihyperglycemic activity; however, the molecular mechanisms remain unclear. To understand the potential effects it has on type 2 diabetes (T2D), the glycolipid metabolism and gut microbiota regulation of phenolic-rich extracts from noni fruit (NFEs) were investigated. The results indicated that NFE could remarkably ameliorate hyperglycemia, insulin resistance, oxidative stress, and glycolipid metabolism via the adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway in T2D mice. Furthermore, metagenomic sequencing results revealed that NFE intervention modulated the gut microbiota composition in T2D mice, characterized by increased abundance of unclassified_o_Bacteroidales, Alistipes, Prevotella, Lactobacillus, and Akkermansia and decreased abundance of Oscillibacter, Desulfovibrio, and significantly decreased the pathways related to carbohydrate metabolism, translation, amino acid metabolism, and nucleotide metabolism. Taken together, the results provided new evidence that the hypoglycemic and hypolipidemic activities of NFE in T2D were likely attributed to the activation of the liver AMPK pathway and modulation of gut microbiota.

Keywords:  gut microbiota; hypoglycemic; hypolipidemic; noni fruit extract; phenolics; type 2 diabetes

DOI:  https://doi.org/10.1021/acs.jafc.1c07441
Mol Med Rep. 2022 Apr;pii: 122. [Epub ahead of print]25(4):

Ophiopogonin‑B targets PTP1B to inhibit the malignant progression of hepatocellular carcinoma by regulating the PI3K/AKT and AMPK signaling pathways.

Fang Yuan, Qian Gao, Hailin Tang, Jun Shi, Yiqun Zhou.

  Ophiopogonin‑B (OP‑B) is a bioactive component from the root of Ophiopogon japonicus, which can exert anticancer effects on multiple malignant tumors. The present study aimed to uncover the effects of OP‑B on hepatocellular carcinoma (HCC) and the underlying mechanisms. An HCC‑xenografted mouse model was established and subsequently treated with OP‑B (15 and 75 mg/kg) to observe the effects of OP‑B on HCC progression and protein tyrosine phosphatase 1B (PTP1B) expression in vivo. The HCC cell line MHCC97‑H was transfected with either PTP1B overexpression (Ov)‑PTP1B or empty vector control, and then exposed to different concentrations of OP‑B. Subsequently, PTP1B expression, cell viability, proliferation, apoptosis, migration, invasion and angiogenesis were evaluated by western blotting, reverse transcription‑quantitative PCR, Cell Counting Kit‑8, colony formation, TUNEL staining, wound healing, Transwell and tube formation assays. The expression of phosphatidylinositol 3 kinase (PI3K)/AKT and adenosine 5'‑monophosphate‑activated protein kinase (AMPK) was also assessed by western blot assay. The results showed that OP‑B inhibited tumor growth and the expression of Ki67, CD31, VEGFA and PTP1B in HCC xenograft model. The expression of PTP1B in HCC cells was also inhibited by OP‑B in a concentration‑dependent manner. Results from the in vitro studies revealed that OP‑B suppressed cell proliferation, migration, invasion and angiogenesis, and promoted apoptosis of HCC cells. However, PTP1B overexpression reversed the effect of OP‑B on HCC cells. PI3K/AKT was inactivated and AMPK was activated by OP‑B exposure in HCC cells, and PTP1B overexpression blocked these effects. In conclusion, OP‑B effectively inhibited the progression of HCC both in vivo and in vitro. These effects may depend on downregulating PTP1B expression, thereby inactivating the PI3K/AKT pathway and activating the AMPK pathway.

Keywords:  hepatocellular carcinoma; ophiopogonin‑B; protein tyrosine phosphatase 1B

DOI:  https://doi.org/10.3892/mmr.2022.12638
J Agric Food Chem. 2022 Feb 15.

Sesamol Reverses Myofiber-Type Conversion in Obese States via Activating the SIRT1/AMPK Signal Pathway.

Min-Min Hu, Wen-Ya Zheng, Ming-Hui Cheng, Zi-Yu Song, Horia Shaukat, Mahnoor Atta, Hong Qin.

  Obesity can evoke changes of skeletal muscle structure and function, which are characterized by the conversion of myofiber from type I to type II, leading to a vicious cycle of metabolic disorders. Reversing the muscle fiber-type conversion in obese states is a novel strategy for treating those with obesity. Sesamol, a food ingredient compound isolated from sesame seeds, exerted potential antiobesity effects. The present research aimed to explore the therapeutic effects of sesamol on obesity-related skeletal muscle-fiber-type conversion and elucidate the underlying molecular mechanisms through utilizing a high-fat-diet-induced obese C57BL/6J mice model and palmitic acid-exposed C2C12 myotubes. The results showed that sesamol attenuated obesity-related metabolic disturbances, elevated exercise endurance of obese mice, and decreased lipid accumulation and insulin resistance in skeletal muscle. After the treatment with sesamol, the muscular mitochondrial content and biogenesis were increased, accompanied by the enzyme activities and myosin heavy-chain isoform changed from type II fiber to type I fiber. Mechanistic studies revealed that the effects of sesamol on reversing skeletal muscle-fiber-type conversion in obese states were associated with the stimulation of the muscular sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) signal pathway, and these effects could be inhibited by a specific inhibitor of SIRT1, EX-527. In conclusion, our research provided novel evidence that sesamol could regulate myofiber-type conversion to treat obesity and obesity-related metabolic disorders by stimulating the muscular SIRT1/AMPK signal pathway.

Keywords:  SIRT1/AMPK signal pathway; myofiber-type conversion; obesity; sesamol; skeletal muscle

DOI:  https://doi.org/10.1021/acs.jafc.1c08036
Phytomedicine. 2022 Jan 29. pii: S0944-7113(22)00042-3. [Epub ahead of print]99 153964

Salidroside inhibits doxorubicin-induced cardiomyopathy by modulating a ferroptosis-dependent pathway.

Hang Chen, Ji Zhu, Yifei Le, Jieli Pan, Ying Liu, Zhijun Liu, Cui Wang, Xiaobing Dou, Dezhao Lu.

   BACKGROUND: Doxorubicin-induced cardiotoxicity (DIC) limits the clinical application of the drug in treatment of cancers and imposes a severe health burden on the patients. Therefore, there is an urgent need to develop alternative therapeutic strategies or drugs to minimize DIC. Salidroside is a phenylpropanoid glycoside extracted from Rhodiola rosea with multiple biological effects such as anti-inflammation and antioxidant properties. However, its mechanism of action in DIC is still poorly understood.
PURPOSE: The present study was aimed to investigate the role of salidroside in DIC and associated mechanism of action for the described effects.
METHODS: Cardiac dysfunction was induced through treatment of mice with doxorubicin in vivo and in vitro. The mechanism of action of salidroside was investigated using western blot assay, qPCR, immunofluorescence, histochemistry, echocardiography, and high-content imaging system.
RESULTS: Results of the current study found that treatment of mice with salidroside significantly improved doxorubicin-induced cardiac dysfunction, ferroptosis-like cell damage, and fibrosis in vivo. Further, it was noted that salidroside inhibited ferroptosis in vivo and in vitro by limiting iron accumulation, restoring GPX4-dependent antioxidant capacity, and preventing lipid peroxidation at the cellular or mitochondrial levels. Mechanistically, salidroside inhibited DOX-induced mitochondrial ROS, Fe2+, and lipid peroxidation as well as restored mitochondrial membrane potential by promoting mitochondrial biogenesis, improving mitochondrial iron-sulfur clusters, and restoring mitochondrial OXPHOS complexes, thereby improving mitochondrial function. In addition, AMPK is a key protein that coordinates mitochondria, metabolism, and ferroptosis. Therefore, it was found that compound C (CC), an AMPK inhibitor, disrupted the regulation of cellular lipid metabolism and mitochondrial function of salidroside as well as led to failure of the protective effect of salidroside against ferroptotic cell death.
CONCLUSIONS: The present study evidently demonstrated the cardioprotective effects of salidroside against doxorubicin-induced cardiomyopathy. Further, salidroside markedly down-regulated ferroptotic cell death by activating AMPK-dependent signaling pathways including regulating abnormal fatty acid metabolism and maintaining mitochondrial function. Therefore, salidroside is can be exploited to develop a novel medication for clinical DIC and salidroside may represent a novel treatment that improves recovery from DIC by targeting ferroptosis.

Keywords:  AMPK signaling pathway; Cardiomyocytes; Doxorubicin-induced cardiomyopathy; Ferroptosis, Salidroside; Mitochondria

DOI:  https://doi.org/10.1016/j.phymed.2022.153964
Sci Rep. 2022 Feb 15. 12(1): 2553

Tofacitinib and metformin reduce the dermal thickness and fibrosis in mouse model of systemic sclerosis.

Ahmet Karatas, Burak Oz, Cigdem Celik, Zeynel Abidin Akar, Ramazan Fazil Akkoc, Ebru Onalan Etem, Adile Ferda Dagli, Suleyman Serdar Koca.

Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway is important in the process of inflammation and fibrosis. The adenosine 5'-monophosphate-activated protein kinase (AMPK) enzyme can affect JAK/STAT pathway. Tofacitinib is a pan-JAK inhibitör. Metformin activates AMPK enzyme. We aimed to investigate the therapeutic efficacy of tofacitinib and metformin on IL-17 and TGF-β cytokines, skin fibrosis and inflammation in mouse model of systemic sclerosis (SSc). 40 Balb/c female mice were divided into 4 groups: (control, sham (BLM), tofacitinib and metformin). The mice in the tofacitinib group received oral tofacitinib (20 mg/kg/daily) and mice in the metformin group received oral metformin (50 mg/kg/day) for 28 days. At the end of 4th week, all groups of mice were decapitated and tissue samples were taken for analysis. Histopathological analysis of skin tissue was performed, and mRNA expressions of collagen 3A, IL-17 and TGF-β were assessed by real-time PCR and ELISA. Repeated BLM injections had induced dermal fibrosis. Moreover, the tissue levels of collagen 3A, IL-17 and TGF-β were elevated in the BLM group. Tofacitinib and metformin mitigated dermal fibrosis. They reduced dermal thickness and tissue collagen 3A, IL-17 and TGF-β levels. Tofacitinib and metformin demonstrated anti-inflammatory and anti-fibrotic effects in the mouse model of SSc.

DOI: https://doi.org/10.1038/s41598-022-06581-1
Cells. 2022 Jan 25. pii: 404. [Epub ahead of print]11(3):

Multistability in Macrophage Activation Pathways and Metabolic Implications.

Carsten Geiß, Elvira Salas, Jose Guevara-Coto, Anne Régnier-Vigouroux, Rodrigo A Mora-Rodríguez.

  Macrophages are innate immune cells with a dynamic range of reversible activation states including the classical pro-inflammatory (M1) and alternative anti-inflammatory (M2) states. Deciphering how macrophages regulate their transition from one state to the other is key for a deeper understanding of inflammatory diseases and relevant therapies. Common regulatory motifs reported for macrophage transitions, such as positive or double-negative feedback loops, exhibit a switchlike behavior, suggesting the bistability of the system. In this review, we explore the evidence for multistability (including bistability) in macrophage activation pathways at four molecular levels. First, a decision-making module in signal transduction includes mutual inhibitory interactions between M1 (STAT1, NF-KB/p50-p65) and M2 (STAT3, NF-KB/p50-p50) signaling pathways. Second, a switchlike behavior at the gene expression level includes complex network motifs of transcription factors and miRNAs. Third, these changes impact metabolic gene expression, leading to switches in energy production, NADPH and ROS production, TCA cycle functionality, biosynthesis, and nitrogen metabolism. Fourth, metabolic changes are monitored by metabolic sensors coupled to AMPK and mTOR activity to provide stability by maintaining signals promoting M1 or M2 activation. In conclusion, we identify bistability hubs as promising therapeutic targets for reverting or blocking macrophage transitions through modulation of the metabolic environment.

Keywords:  bistability; macrophage; metabolism; miRNA; multistability; systems biology

DOI:  https://doi.org/10.3390/cells11030404
Int J Mol Sci. 2022 Jan 18. pii: 1044. [Epub ahead of print]23(3):

Quercetin Reduces Lipid Accumulation in a Cell Model of NAFLD by Inhibiting De Novo Fatty Acid Synthesis through the Acetyl-CoA Carboxylase 1/AMPK/PP2A Axis.

Antonio Gnoni, Benedetta Di Chiara Stanca, Laura Giannotti, Gabriele Vincenzo Gnoni, Luisa Siculella, Fabrizio Damiano.

  Dysregulation of de novo lipogenesis (DNL) has recently gained strong attention as being one of the critical factors that contribute to the assessment of non-alcoholic fatty liver disease (NAFLD). NAFLD is often diagnosed in patients with dyslipidemias and type 2 diabetes; thus, an interesting correlation can be deduced between high hematic free fatty acids and glucose excess in the DNL dysregulation. In the present study, we report that, in a cellular model of NAFLD, the coexistence of elevated glucose and FFA conditions caused the highest cellular lipid accumulation. Deepening the molecular mechanisms of the DNL dysregulation-RT-qPCR and immunoblot analysis demonstrated increased expression of mitochondrial citrate carrier (CiC), cytosolic acetyl-CoA carboxylase 1 (ACACA), and diacylglycerol acyltransferase 2 (DGAT2) involved in fatty acids and triglycerides synthesis, respectively. XBP-1, an endoplasmic reticulum stress marker, and SREBP-1 were the transcription factors connected to the DNL activation. Quercetin (Que), a flavonoid with strong antioxidant properties, and noticeably reduced the lipid accumulation and the expression of SREBP-1 and XBP-1, as well as of their lipogenic gene targets in steatotic cells. The anti-lipogenic action of Que mainly occurs through a strong phosphorylation of ACACA, which catalyzes the committing step in the DNL pathway. The high level of ACACA phosphorylation in Que-treated cells was explained by the intervention of AMPK together with the reduction of enzymatic activity of PP2A phosphatase. Overall, our findings highlight a direct anti-lipogenic effect of Que exerted through inhibition of the DNL pathway by acting on ACACA/AMPK/PP2A axis; thus, suggesting this flavonoid as a promising molecule for the NAFLD treatment.

Keywords:  AMP-activated protein kinase; acetyl-CoA carboxylase 1; citrate carrier; de novo lipogenesis; endoplasmic reticulum stress; non-alcoholic fatty liver disease; protein phosphatase 2A; quercetin; sterol regulatory element-binding protein 1

DOI:  https://doi.org/10.3390/ijms23031044