bims-amsmem 2023-01-01 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2023–01–01
eight papers selected by
Dipsikha Biswas, Københavns Universitet

Empagliflozin attenuates the renal tubular ferroptosis in diabetic kidney disease through AMPK/NRF2 pathway.
Xanthine oxidoreductase mediates genotoxic drug-induced autophagy and apoptosis resistance by uric acid accumulation and TGF-β-activated kinase 1 (TAK1) activation.
Sodium butyrate protects against rotavirus-induced intestinal epithelial barrier damage by activating AMPK-Nrf2 signaling pathway in IPEC-J2 cells.
Bone marrow mesenchymal stem cells alleviate stress-induced hyperalgesia via restoring gut microbiota and inhibiting neuroinflammation in the spinal cord by targeting the AMPK/NF-κB signaling pathway.
Pathogenesis-related protein 1 suppresses oomycete pathogen by targeting against AMPK kinase complex.
GAS6/Axl is associated with AMPK activation and attenuates H2O2-induced oxidative stress.
Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway.
Ginkgo biloba extracts protect human retinal Müller glial cells from t-BHP induced oxidative damage by activating the AMPK-Nrf2-NQO-1 axis.

Free Radic Biol Med. 2022 Dec 26. pii: S0891-5849(22)01114-5. [Epub ahead of print]195 89-102

Empagliflozin attenuates the renal tubular ferroptosis in diabetic kidney disease through AMPK/NRF2 pathway.

QianYu Lu, LiJiao Yang, Jing-Jie Xiao, Qing Liu, LiHua Ni, Jun-Wei Hu, Hong Yu, XiaoYan Wu, Bai-Fang Zhang.

  Renal tubular damage plays a key role in the pathogenesis of diabetic kidney disease (DKD), and one of the main pathological process associated with DKD in diabetic mice is the ferroptosis, a novel form of cell death caused by iron-dependent lipid peroxidation. Several researches suggested that empagliflozin may treat renal injury, but its effects on diabetic-related ferroptosis and underlying mechanisms were not fully elucidated. In this study, the influence of empagliflozin on renal injury was evaluated in vivo and in vitro in a mouse model and in high-glucose (HG) or Erastin-stimulated renal HK-2 cell line, respectively. Ferroptosis-related markers were assessed, including GSH, labile iron levels, and ferroptosis regulators by Western blot, qRT-PCR, immunohistochemistry, and immunofluorescence. The level of malondialdehyde (MDA) and the fluorescence intensity of BODIPY probe indicated the level of lipid peroxidation. It was demonstrated that solute carrier family 7, member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were less expressed in renal biopsy samples from patients affected by DKD than in those from non-diabetic renal disease patients (NDRD), proving the ferroptosis of tubular epithelial cells in case of DKD. Furthermore, empagliflozin markedly decreased the ferroptosis impairment in DKD mice, as well as in HG model of HK-2 cells. Our investigations showed the ability of empagliflozin to suppress ferroptosis was partially countered by AMP-activated protein kinase (AMPK) inhibitor, which led to a reduction of the nuclear translocation of the antioxidant transcription factor NFE2-related factor 2 (NRF2) and downregulation of target genes such as GPX4, ferritin heavy chain 1 (FTH1), and SLC7A11, while AMPK agonists were responsible for the enhancement of the protective effects of empagliflozin. Taken together, our findings showed that empagliflozin may prevent the development of ferroptosis by promoting the AMPK-mediated NRF2 activation pathway, providing important insights for possible novel treatment approaches for DKD.

Keywords:  AMP-activated protein kinase; Diabetic kidney disease; Empagliflozin; Ferroptosis; NFE2-related factor 2

DOI:  https://doi.org/10.1016/j.freeradbiomed.2022.12.088
FASEB J. 2023 Feb;37(2): e22723

Xanthine oxidoreductase mediates genotoxic drug-induced autophagy and apoptosis resistance by uric acid accumulation and TGF-β-activated kinase 1 (TAK1) activation.

Jingxiang Wang, Yanhua Hu, Penggang Liu, Xiulong Xu.

  Autophagy is a highly conserved cellular process that profoundly impacts the efficacy of genotoxic chemotherapeutic drugs. TGF-β-activated kinase 1 (TAK1) is a serine/threonine kinase that activates several signaling pathways involved in inducing autophagy and suppressing cell death. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme that converts hypoxanthine to xanthine, and xanthine to uric acid and hydrogen peroxide in the purine catabolism pathway. Recent studies showed that uric acid can bind to TAK1 and prolong its activation. We hypothesized that genotoxic drugs may induce autophagy and apoptosis resistance by activating TAK1 through XOR-generated uric acid. Here, we report that gemcitabine and 5-fluorouracil (5-FU), two genotoxic drugs, induced autophagy in HeLa and HT-29 cells by activating TAK1 and its two downstream kinases, AMP-activated kinase (AMPK) and c-Jun terminal kinase (JNK). XOR knockdown and the XOR inhibitor allopurinol blocked gemcitabine-induced TAK1, JNK, AMPK, and Unc51-like kinase 1 (ULK1)S555 phosphorylation and gemcitabine-induced autophagy. Inhibition of the ATM-Chk pathway, which inhibits genotoxic drug-induced uric acid production, blocked gemcitabine-induced autophagy by inhibiting TAK1 activation. Exogenous uric acid in its salt form, monosodium urate (MSU), induced autophagy by activating TAK1 and its downstream kinases JNK and AMPK. Gene knockdown or the inhibitors of these kinases blocked gemcitabine- and MSU-induced autophagy. Inhibition of autophagy by allopurinol, chloroquine, and 5Z-7-oxozeaenol (5Z), a TAK1-specific inhibitor, enhanced gemcitabine-induced apoptosis. Our study uncovers a previously unrecognized role of XOR in regulating genotoxic drug-induced autophagy and apoptosis and has implications for designing novel therapeutic strategies for cancer treatment.

Keywords:  TAK1; XOR; apoptosis; autophagy; genotoxic drugs; uric acid

DOI:  https://doi.org/10.1096/fj.202201436R
Int J Biol Macromol. 2022 Dec 22. pii: S0141-8130(22)03130-0. [Epub ahead of print]228 186-196

Sodium butyrate protects against rotavirus-induced intestinal epithelial barrier damage by activating AMPK-Nrf2 signaling pathway in IPEC-J2 cells.

Xia Dong, Yi Wang, Xiaoxiao Zhu, Linyuan Shen, Lei Chen, Lili Niu, Mailin Gan, Shunhua Zhang, Ming Zhang, Jun Jiang, Daiwen Chen, Li Zhu, Ye Zhao.

  Rotavirus (RV) mainly infects intestinal epithelial cells, which leads to diarrhea in newborn piglets with dysfunction in the intestinal mucosal mechanical barrier. Sodium butyrate (SB) is one of the metabolites excreted by gut microbes. However, the protective effect of SB on RV infection induced intestinal mucosal mechanical barrier injury and its potential mechanism has not been well elucidated. In the present study, IPEC-J2 cells with RV infection was a model of intestinal mucosal mechanical barrier injury. Our results demonstrated that the appropriate concentration of SB can effectively alleviate TJ structural damage and up-regulating the expression of TJ-related genes. Furthermore, the appropriate concentration of SB can effectively reverse the increase of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) level induced by RV infection. Meanwhile, the levels of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-px) and antioxidant proteins NAD(P)H dehydrogenase quinone 1 (NQO1) and heme oxygenase-1 (HO-1) were increased through SB treatment. In addition, we found that SB increased cellular antioxidant capacity by activating the adenosine monophosphate-activated protein kinase (AMPK)-nuclear factor erythroid 2-related factor (Nrf2) signaling pathway and the cytoprotective effect of SB is limited by GPR109A siRNA. Thus, our findings revealed that SB reduces oxidative stress caused by RV infection and restores the intestinal mucosal mechanical barrier function by activating the AMPK-Nrf2 signal pathway mediated by the receptor GPR109A.

Keywords:  IPEC-J2 cells; Intestinal mucosal mechanical barrier; Oxidative stress; Rotavirus; Sodium butyrate

DOI:  https://doi.org/10.1016/j.ijbiomac.2022.12.219
Life Sci. 2022 Dec 22. pii: S0024-3205(22)01018-9. [Epub ahead of print] 121318

Bone marrow mesenchymal stem cells alleviate stress-induced hyperalgesia via restoring gut microbiota and inhibiting neuroinflammation in the spinal cord by targeting the AMPK/NF-κB signaling pathway.

Xi Tan, Danning Wang, Pei Lu, Shaodi Guan, Quanjing Zheng, Xiaoyi Du, Hui Xu.

  Aim Spinal neuroinflammation contributes to the mechanism of stress-induced hyperalgesia (SIH). Recent research has demonstrated that bone marrow mesenchymal stem cells (BMSCs) alleviate chronic pain. However, what remains unidentified is whether BMSCs could improve hyperalgesia induced by chronic restraint stress (CRS). In another dimension, our previous study proved that gut microbiota played an important role in CRS-induced hyperalgesia in mice. Yet, whether BMSCs treatments change gut microbiota composition in CRS mice remains unexplored.
MAIN METHODS: Mechanical allodynia and thermal hyperalgesia were used to assess pain behavior. Composition of fecal samples were verified by 16S rRNA analysis. Western blot was used to investigate the expression of adenosine monophosphate-activated protein kinase (AMPK)/ nuclear factor kappa B (NF-κB) signaling pathway, pro-inflammatory cytokines [interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), IL-6], and the markers of microglia and astrocytes. The morphology of glia cells was evaluated by immunofluorescence staining.
KEY FINDINGS: CRS down-regulated phosphorylated AMPK (p-AMPK), up-regulated phosphorylated NF-κB p65 (p-NF-κB p65), activated microglia and astrocytes and promoted the secretion of IL-1β, TNF-α and IL-6 in the spinal cord. BMSCs alleviated CRS-induced hyperalgesia by inhibiting the activation of microglia and astrocytes and by reducing neuroinflammation via improving the disrupted AMPK/NF-κB pathway. Furthermore, BMSCs also raised the relative abundance of Muribaculaceae and Lachnospiraceae in CRS mice feces, which was significantly related to its effect of relieving hyperalgesia.
SIGNIFICANCE: Our results support that BMSCs could alleviate CRS-induced hyperalgesia by reducing AMPK/NF-κB-dependent neuroinflammation in the spinal cord and restoring the homeostasis of gut microbiota.

Keywords:  AMPK/NF-κB pathway; Bone marrow mesenchymal stem cells; Chronic restraint stress; Gut microbiota; Stress-induced hyperalgesia

DOI:  https://doi.org/10.1016/j.lfs.2022.121318
J Adv Res. 2023 Jan;pii: S2090-1232(22)00033-9. [Epub ahead of print]43 13-26

Pathogenesis-related protein 1 suppresses oomycete pathogen by targeting against AMPK kinase complex.

Xiumei Luo, Tingting Tian, Li Feng, Xingyong Yang, Linxuan Li, Xue Tan, Wenxian Wu, Zhengguo Li, Haim Treves, Francois Serneels, I-Son Ng, Kan Tanaka, Maozhi Ren.

   INTRODUCTION: During the arms race between plants and pathogens, pathogenesis-related proteins (PR) in host plants play a crucial role in disease resistance, especially PR1. PR1 constitute a secretory peptide family, and their role in plant defense has been widely demonstrated in both hosts and in vitro. However, the mechanisms by which they control host-pathogen interactions and the nature of their targets within the pathogen remain poorly understood.
OBJECTIVES: The present study was aimed to investigate the anti-oomycete activity of secretory PR1 proteins and elaborate their underlying mechanisms.
METHODS: This study was conducted in the potato-Phytophthora infestans pathosystem. After being induced by the pathogen infection, the cross-kingdom translocation of secretory PR1 was demonstrated by histochemical assays and western blot, and their targets in P. infestans were identified by yeast-two-hybrid assays, bimolecular fluorescence complementation assays, and co-immunoprecipitation assay.
RESULTS: The results showed that the expression of secretory PR1-encoding genes was induced during pathogen infection, and the host could deliver PR1 into P. infestans to inhibit its vegetative growth and pathogenicity. The translocated secretory PR1 targeted the subunits of the AMPK kinase complex in P. infestans, thus affecting the AMPK-driven phosphorylation of downstream target proteins, preventing ROS homeostasis, and down-regulating the expression of RxLR effectors.
CONCLUSION: The results provide novel insights into the molecular function of PR1 in protecting plants against pathogen infection, and uncover a potential target for preventing pre- and post-harvest late blight.

Keywords:  AMPK kinase complex; Cross-kingdom translocation; Host-pathogen interaction; Pathogenesis-related protein 1; Phytophthora infestans; Potato late blight

DOI:  https://doi.org/10.1016/j.jare.2022.02.002
Apoptosis. 2022 Dec 29.

GAS6/Axl is associated with AMPK activation and attenuates H2O2-induced oxidative stress.

Zhenxing Liang, Yang Yang, Xue Wu, Chenxi Lu, Huadong Zhao, Kehan Chen, Aizhen Zhao, Xiyang Li, Jing Xu.

  Oxidative stress plays a key part in cardiovascular event. Growth arrest-specific gene 6 (GAS6) is a vitamin K-dependent ligand which has been shown to exert important effects in heart. The effects of GAS6 were evaluated against hydrogen peroxide (H2O2) ‑induced oxidative stress injury in HL-1 cardiomyocytes. A series of experimental methods were used to analyze the effects of GAS6 on cell viability, apoptosis, oxidative stress, mitochondrial function and AMPK/ACC signaling in H2O2‑injured HL-1 cells. In this study, we found that H2O2 reduced cell viability, increased apoptotic rate and intracellular reactive oxygen species (ROS). Meanwhile, H2O2 decreased the protein levels of GAS6, and increased the protein level of p-AMPK/AMPK, p-ACC/ACC. Then, we observed that overexpression of GAS6 significantly reduced cell death, manifested as increased cell viability, improved oxidative stress, apoptosis and upregulated the levels of GAS6, p-Axl/Axl, Nrf2, NQO1, HO-1, Bcl-2/Bax, PGC-1α, NRF1, TFAM, p-AMPK/AMPK, and p-ACC/ACC-related protein expression in HL-1 cells and H2O2‑injured cardiomyocytes. To further verify the results, we successfully constructed GAS6 lentiviral vectors, and found GAS6 shRNA partially reversed the above results. These data suggest that AMPK/ACC may be a downstream effector molecule in the antioxidant action of GAS6. In summary, our findings indicate that activation GAS6/Axl-AMPK signaling protects H2O2‑induced oxidative stress which is accompanied by the amelioration of oxidative stress, apoptosis, and mitochondrial function.

Keywords:  ACC; AMPK; Apoptosis; GAS6; Oxidative stress

DOI:  https://doi.org/10.1007/s10495-022-01801-5
Neural Regen Res. 2023 Jul;18(7): 1553-1562

Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway.

Jin-Yun Zhao, Xiao-Long Sheng, Cheng-Jun Li, Tian Qin, Run-Dong He, Guo-Yu Dai, Yong Cao, Hong-Bin Lu, Chun-Yue Duan, Jian-Zhong Hu.

  Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury. However, its effect on spinal cord injury in aged mice remains unclear. Considering the essential role of angiogenesis during the regeneration process, we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells, thereby promoting microvascular regeneration in aged mice after spinal cord injury. In this study, we established young and aged mouse models of contusive spinal cord injury using a modified Allen method. We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord. Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro. Furthermore, intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord, thereby improving neurological function. The role of metformin was reversed by compound C, an adenosine monophosphate-activated protein kinase inhibitor, both in vivo and in vitro, suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury. These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway, thereby improving the neurological function of aged mice after spinal cord injury.

Keywords:  adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway; aged mice; angiogenesis; compound C; metformin; spinal cord injury

DOI:  https://doi.org/10.4103/1673-5374.360245
J Pharm Pharmacol. 2022 Dec 30. pii: rgac095. [Epub ahead of print]

Ginkgo biloba extracts protect human retinal Müller glial cells from t-BHP induced oxidative damage by activating the AMPK-Nrf2-NQO-1 axis.

Yue Li, Ke Wang, Xue Zhu, Zhengqi Cheng, Ling Zhu, Michael Murray, Fanfan Zhou.

   OBJECTIVES: Retinal Müller glial cell loss is almost involved in all retinal diseases, especially diabetic retinopathy (DR). Oxidative stress significantly contributes to the development of Müller glial cell loss. Ginkgo biloba extracts (GBE) have been reported to possess antioxidant property, beneficial in treating human retinal diseases. However, little is known about its role in Müller glial cells. This study investigated the protective effect of GBE (prepared from ginkgo biloba dropping pills) in human Müller glial cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress and its underlying molecular mechanism.
METHODS: MIO-M1 cells were pretreated with or without GBE prior to the exposure to t-BHP-induced oxidative stress. Cell viability, cell death profile and lipid peroxidation were subsequently assessed. Protein expression of the key anti-oxidative signalling factors were investigated.
KEY FINDINGS: We showed that GBE can effectively protect human MIO-M1 cells from t-BHP-induced oxidative injury by improving cell viability, reducing intracellular ROS accumulation and suppressing lipid peroxidation, which effect is likely mediated through activating AMPK-Nrf2-NQO-1 antioxidant respondent axis.
CONCLUSIONS: Our study is the first to reveal the great potentials of GBE in protecting human retinal Müller glial cell loss against oxidative stress. GBE might be used to prevent human retinal diseases particularly DR.

Keywords:  Ginkgo biloba extracts; Nrf2; antioxidant; diabetic retinopathy; oxidative stress

DOI:  https://doi.org/10.1093/jpp/rgac095