bims-amsmem 2022-10-30 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022‒10‒30
24 papers selected by
Dipsikha Biswas, Københavns Universitet

AMPK activation is sufficient to increase skeletal muscle glucose uptake and glycogen synthesis but is not required for contraction-mediated increases in glucose metabolism.
AMPK-driven Macrophage Responses are Autophagy-dependent in Experimental Bronchopulmonary Dysplasia.
AMPK Amplifies IL2-STAT5 Signaling to Maintain Stability of Regulatory T Cells in Aged Mice.
RhFGF21 Protects Epidermal Cells against UVB-Induced Apoptosis through Activating AMPK-Mediated Autophagy.
Red Pepper Seeds Inhibit Hepatic Lipid Accumulation by Inducing Autophagy via AMPK Activation.
Adiponectin Protects Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury by Suppressing Autophagy.
Hernandezine induces autophagic cell death in human pancreatic cancer cells via activation of the ROS/AMPK signaling pathway.
SHP-1 knockdown suppresses mitochondrial biogenesis and aggravates mitochondria-dependent apoptosis induced by all trans retinal through the STING/AMPK pathways.
Effects of metformin on Sonic hedgehog subgroup medulloblastoma progression: In vitro and in vivo studies.
Adenosine diphosphate-ribosylation factor-like 15 can regulate glycolysis and lipogenesis related genes in colon cancer.
PEDF inhibits non‑small cell lung cancer proliferation by suppressing autophagy through downregulation of AMPK‑ULK1 signaling.
New mechanism of metformin action mediated by lysosomal presenilin enhancer 2.
Dexmedetomidine alleviates pain in MPTP-treated mice by activating the AMPK/mTOR/NF-κB pathways in astrocytes.
Narciclasine ameliorated T cell mediated acute liver injury through activating AMPK pathway.
hUMSCs Transplantation Regulates AMPK/NR4A1 Signaling Axis to Inhibit Ovarian Fibrosis in POI Rats.
IKCa channels control breast cancer metabolism including AMPK-driven autophagy.
A new LKB1 activator, piericidin analogue S14, retards renal fibrosis through promoting autophagy and mitochondrial homeostasis in renal tubular epithelial cells.
Alpha-lipoic acid activates AMPK to protect against oxidative stress and apoptosis in rats with diabetic peripheral neuropathy.
The Potential Therapeutic Role of Metformin in Diabetic and Non-Diabetic Bone Impairment.
Modulation of hypothalamic AMPK phosphorylation by olanzapine controls energy balance and body weight.
FABP5 Deficiency Impaired Macrophage Inflammation by Regulating AMPK/NF-κB Signaling Pathway.
Thymoquinone‑induced autophagy mitigates doxorubicin‑induced H9c2 cell apoptosis.
Mfn2-mediated mitochondrial fusion promotes autophagy and suppresses ovarian cancer progression by reducing ROS through AMPK/mTOR/ERK signaling.
Deficiency of miR-29a/b1 leads to premature aging and dopaminergic neuroprotection in mice.

Heliyon. 2022 Oct;8(10): e11091

AMPK activation is sufficient to increase skeletal muscle glucose uptake and glycogen synthesis but is not required for contraction-mediated increases in glucose metabolism.

Ryan M Esquejo, Bina Albuquerque, Anna Sher, Matthew Blatnik, Kyle Wald, Matthew Peloquin, Jake Delmore, Erick Kindt, Wenlin Li, Jamey D Young, Kim Cameron, Russell A Miller.

  The AMP-activated protein kinase (AMPK) is a cellular sensor of energetics and when activated in skeletal muscle during contraction can impart changes in skeletal muscle metabolism. Therapeutics that selectively activate AMPK have been developed to lower glucose levels through increased glucose disposal rates as an approach to abrogate the hyperglycemic state of diabetes; however, the metabolic fate of glucose following AMPK activation remains unclear. We have used a combination of in vivo evaluation of glucose homeostasis and ex vivo skeletal muscle incubation to systematically evaluate metabolism following pharmacological activation of AMPK with PF-739, comparing this with AMPK activation through sustained intermittent electrical stimulation of contraction. These methods to activate AMPK result in increased glucose uptake but divergent metabolism of glucose: pharmacological activation results in increased glycogen accumulation while contraction-induced glucose uptake results in increased lactate formation and glucose oxidation. These results provide additional evidence to support a role for AMPK in control of skeletal muscle metabolism and additional insight into the potential for AMPK stimulation with small molecule direct activators.

Keywords:  AMPK; Metabolism; Pharmacology; Skeletal muscle

DOI:  https://doi.org/10.1016/j.heliyon.2022.e11091
Am J Respir Cell Mol Biol. 2022 Oct 28.

AMPK-driven Macrophage Responses are Autophagy-dependent in Experimental Bronchopulmonary Dysplasia.

Sourabh Soni, Yujie Jiang, Liang Zhang, Abhijeet Thakur, Sule Cataltepe.

  The pathogenesis of bronchopulmonary dysplasia (BPD) remains incompletely understood. Recent studies suggest insufficient adenosine monophosphate-activated protein kinase (AMPK) activation as a potential cause of impaired autophagy in rodent and non-human primate (NHP) models of BPD. Impaired autophagy is associated with enhanced inflammatory signaling in alveolar macrophages (AM) and increased severity of murine BPD induced by neonatal hyperoxia exposure. The goal of this study was to determine the role of autophagy and AMPK activation in macrophage responses in murine BPD. C57BL/6J mice were exposed to neonatal hyperoxia starting on postnatal day (P)1 and treated with the AMPK activator, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) between P3 and P6. Mice were euthanized on P7 and markers of AMPK activation and autophagy were assessed by immunoblotting. Alveolarization was assessed using radial alveolar counts, mean linear intercept measurements, and quantification of alveolar septal myofibroblasts. Relative mRNA expression of M1-like and M2-like genes was assessed in AMs isolated from bronchoalveolar lavage (BAL) fluid from WT, LysMCre--Becn1fl/fl and LysMCre+-Becn1fl/fl mice following neonatal hyperoxia exposure. AICAR treatment resulted in AMPK activation and induction of autophagic activity in whole lung and BAL cell lysates and attenuated hyperoxia-induced alveolar simplification in neonatal lungs. AICAR-treated control but not Beclin1-deficient AMs demonstrated significantly decreased expression of M1-like markers and significantly increased expression of M2-like markers. In conclusion, pharmacologic activation of AMPK by AICAR resulted in induction of autophagy and played a protective role, at least in part, through attenuation of pro-inflammatory signaling in AMs via autophagy-dependent mechanisms in a murine model of BPD.

Keywords:  AICAR; AMPK; Alveolar macrophages; Autophagy; Bronchopulmonary dysplasia

DOI:  https://doi.org/10.1165/rcmb.2022-0282OC
Int J Mol Sci. 2022 Oct 16. pii: 12384. [Epub ahead of print]23(20):

AMPK Amplifies IL2-STAT5 Signaling to Maintain Stability of Regulatory T Cells in Aged Mice.

Ram Hari Pokhrel, Ben Kang, Maheshwor Timilshina, Jae-Hoon Chang.

  AMP-activated protein kinase (AMPK), an important regulator of the aging process, is expressed in various immune cells. However, its role in regulatory T cell (Treg) stability during aging is poorly understood. Here, we addressed the role of AMPK in Treg function and stability during aging by generating Treg-specific AMPKα1 knockout mice. In this study, we found that AMPKα1-deficient Tregs failed to control inflammation as effectively as normal Tregs did during aging. AMPK knockout from Tregs reduces STAT5 phosphorylation in response to interleukin (IL)-2 stimulation, thereby destabilizing Tregs by decreasing CD25 expression. Thus, our study addressed the role of AMPK in Tregs in sensing IL-2 signaling to amplify STAT5 phosphorylation, which, in turn, supports Treg stability by maintaining CD25 expression and controlling inflamm-aging.

Keywords:  AMPK; Treg stability; aging; inflammation

DOI:  https://doi.org/10.3390/ijms232012384
Int J Mol Sci. 2022 Oct 18. pii: 12466. [Epub ahead of print]23(20):

RhFGF21 Protects Epidermal Cells against UVB-Induced Apoptosis through Activating AMPK-Mediated Autophagy.

Yeli Zhao, Jingjing Lin, Jiana Li, Canol Bwalya, Yuyun Xu, Yue Niu, Yujie Zhang, Junyi Wu, Yifan Xu, Jun Chen, Shasha Ye, Li Lin.

  Ultraviolet irradiation, especially ultraviolet B (UVB) irradiation, increases the risks of various skin diseases, such as sunburn, photo-aging and cancer. However, few drugs are available to treat skin lesions. Therefore, the discovery of drugs to improve the health of irradiated skin is urgently needed. Fibroblast growth factor 21 (FGF21) is a metabolic factor that plays an important role in the protection and repair of various types of pathological damage. The effects of FGF21 on skin injury caused by UVB-irradiation were the focus of this study. We found that UVB irradiation promoted the expression of FGF21 protein in mouse epidermal cells, and exogenous recombinant human FGF21 (rhFGF21) protected mouse skin tissue against UVB-induced injury. RhFGF21 inhibited the inflammatory responses and epidermal cell apoptosis as well as promotion of autophagy in UVB-irradiated mice. Moreover, we found that rhFGF21 protected HaCaT cells against UVB-induced apoptosis, and the protective effect was enhanced by treatment with an autophagy activator (rapamycin) but was inhibited by treatment with an autophagy inhibitor (3-methyladenine, 3MA). AMP-activated protein kinase (AMPK), as a cellular energy sensor, regulates autophagy. RhFGF21 increased the expression of p-AMPK protein in epidermal cells irradiated with UVB in vivo and in vitro. Moreover, rhFGF21 increased autophagy levels and the viability were diminished by treatment with an AMPK inhibitor (compound C). RhFGF21 protects epidermal cells against UVB-induced apoptosis by inducing AMPK-mediated autophagy.

Keywords:  AMPK; UVB; apoptosis; autophagy; rhFGF21

DOI:  https://doi.org/10.3390/ijms232012466
Nutrients. 2022 Oct 12. pii: 4247. [Epub ahead of print]14(20):

Red Pepper Seeds Inhibit Hepatic Lipid Accumulation by Inducing Autophagy via AMPK Activation.

Young-Hyun Lee, Hwa-Jin Kim, Mikyoung You, Hyeon-A Kim.

  Although the red pepper and its seeds have been studied for metabolic diseases, the effects and potential mechanisms of red pepper seed extract (RPS) on hepatic lipid accumulation are not yet completely understood. This study aimed to evaluate the inhibitory effect of RPS on hepatic lipid accumulation via autophagy. C57BL/6 mice were fed a high-fat diet (HFD) or a HFD supplemented with RPS. RPS treatment inhibited hepatic lipid accumulation by suppressing lipogenesis, inducing hepatic autophagic flux, and activating AMPK in HFD-fed mice. To investigate the effect of RPS on an oleic acid (OA)-induced hepatic steatosis cell model, HepG2 cells were incubated in a high-glucose medium and OA, followed by RPS treatment. RPS treatment decreased OA-induced lipid accumulation and reduced the expression of lipogenesis-associated proteins. Autophagic flux dramatically increased in the RPS-treated group. RPS phosphorylated AMPK in a dose-dependent manner, thereby dephosphorylated mTOR. Autophagy inhibition with 3-methyladenine (3-MA) antagonized RPS-induced suppression of lipogenesis-related protein expressions. Moreover, the knockdown of endogenous AMPK also antagonized the RPS-induced regulation of lipid accumulation and autophagy. Our findings provide new insights into the beneficial effects of RPS on hepatic lipid accumulation through the AMPK-dependent autophagy-mediated downregulation of lipogenesis.

Keywords:  AMPK/mTOR; autophagy; lipogenesis; non-alcoholic fatty liver diseases; red pepper seed

DOI:  https://doi.org/10.3390/nu14204247
J Immunol Res. 2022 ;2022 8433464

Adiponectin Protects Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury by Suppressing Autophagy.

Jia Guo, Kaiyi Zhu, Zhidong Li, Chuanshi Xiao.

Adiponectin is a cytokine produced by adipocytes and acts as a potential cardioprotective agent and plays an important role in myocardial ischemia/reperfusion injury. In a myocardial hypoxia/reoxygenation model using neonatal rat ventricular myocytes, we investigated the contribution of adiponectin-mediated autophagy to its cardioprotective effects. Cardiomyocytes were exposed to hypoxia/reoxygenation pretreated with or without adiponectin in the presence of absence of rapamycin. Cell viability was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Western blotting assay was used to determine the expression levels of microtubule-associated proteins 1A/1B light chain 3B (LC3B), adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), p62/sequestosome 1, unc-51 like autophagy activating kinase 1 (ULK1), and Beclin-1. Autophagosome formation was detected by monodansylcadaverine staining. We found that hypoxia induced a time dependent decline in cardiomyocyte viability, and increase in autophagy and reoxygenation further augmented hypoxia-induced autophagy induction and consequently reduced cell viability. Adiponectin treatment alleviated hypoxia/reoxygenation-induced cellular damage and autophagy in cardiomyocytes. Adiponectin treatment also attenuated hypoxia/reoxygenation-promoted cardiomyocyte autophagy even in the presence of another autophagy stimulator rapamycin in part by inhibiting vacuolar hydron-adenosine triphosphatase. Additionally, autophagy suppression by adiponectin during hypoxia/reoxygenation was associated with the attenuated phosphorylation of AMPK and ULK1, augmented phosphorylation of mTOR, and the reduced protein expression levels of Beclin-1 in cardiomyocytes. Taken together, these results suggest that adiponectin protects ischemia/reperfusion-induced cardiomyocytes by suppressing autophagy in part through AMPK/mTOR/ULK1/Beclin-1 signaling pathway.

DOI: https://doi.org/10.1155/2022/8433464
Acta Pharmacol Sin. 2022 Oct 25.

Hernandezine induces autophagic cell death in human pancreatic cancer cells via activation of the ROS/AMPK signaling pathway.

Chang-Feng Song, Yu-Heng Hu, Zhi-Guo Mang, Zeng Ye, Hai-di Chen, De-Sheng Jing, Gui-Xiong Fan, Shun-Rong Ji, Xian-Jun Yu, Xiao-Wu Xu, Yi Qin.

  Hernandezine (Her) is a bisbenzylisoquinoline alkaloid extracted from the traditional Chinese herbal medicine Thalictrum glandulosissimum. Evidence shows that Her is a natural agonist of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and induces apoptosis and autophagy in tumor cells. In this study, we investigated the role of autophagy in Her-induced cell death in human pancreatic cancer cell lines. We showed that Her dose-dependently suppressed cell proliferation, promoted autophagy and induced autophagic death in pancreatic ductal adenocarcinoma (PDAC) cell lines Capan-1 and SW1990. The IC50 values of Her in inhibition of Capan-1 and SW1990 cells were 47.7 μM and 40.1 μM, respectively. Immunoblotting showed that Her (1-40 μM) promoted the conversion of LC3-I to LC3-II, and Her exerted concentration-dependent and time-dependent effects on autophagy activation in PDAC cells. In transmission electron microscopy and fluorescence image analysis, we found that autophagic vacuoles were significantly increased in Her-treated cells. Knockdown of ATG5, a key gene in the autophagy pathway, alleviated the activation of autophagy by Her. These results demonstrated that Her induced autophagy in PDAC cells. Intensely activated autophagy could promote cell death. The autophagy inhibitors, BafA1 and HCQ significantly inhibited Her-induced cell death, implying that Her induced autophagic cell death in PDAC cells. Moreover, we showed that Her activated autophagy by increasing the phosphorylation of AMPK and decreasing the phosphorylation of mTOR/p70S6K. Knockdown of AMPKα relieves the autophagic cell death induced by Her. Furthermore, Her concentration-dependently enhanced reactive oxygen species (ROS) generation in PDAC cells. Antioxidants could reduce the phosphorylation of AMPK and suppress autophagic cell death induced by Her. Our study provides evidence for the development of Her as a therapeutic agent for the treatment of pancreatic cancer.

Keywords:  ROS; autophagic cell death; autophagy; hernandezine; pancreatic cancer

DOI:  https://doi.org/10.1038/s41401-022-01006-1
Mol Med. 2022 Oct 22. 28(1): 125

SHP-1 knockdown suppresses mitochondrial biogenesis and aggravates mitochondria-dependent apoptosis induced by all trans retinal through the STING/AMPK pathways.

Xiaonan Zhuang, Jun Ma, Gezhi Xu, Zhongcui Sun.

  BACKGROUND: Oxidative stress-caused damage to the retinal pigment epithelium (RPE) underlies the onset and progression of age-related macular degeneration (AMD). Impaired mitochondrial biogenesis sensitizes RPE cells to mitochondrial dysfunction, energy insufficiency and death. Src-homology 2 domain-containing phosphatase (SHP)-1 is important in regulating immune responses and cell survival. However, its roles in cell survival are not always consistent. Until now, the effects of SHP-1 on RPE dysfunction, especially mitochondrial homeostasis, remain to be elucidated. We sought to clarify the effects of SHP-1 in RPE cells in response to atRAL-induced oxidative stress and determine the regulatory mechanisms involved.METHODS: In the all trans retinal (atRAL)-induced oxidative stress model, we used the vector of lentivirus to knockdown the expression of SHP-1 in ARPE-19 cells. CCK-8 assay, Annexin V/PI staining and JC-1 staining were utilized to determine the cell viability, cell apoptosis and mitochondrial membrane potential. We also used immunoprecipitation to examine the ubiquitination modification of stimulator of interferon genes (STING) and its interaction with SHP-1. The expression levels of mitochondrial marker, proteins related to mitochondrial biogenesis, and signaling molecules involved were examined by western blotting analysis.
RESULTS: We found that SHP-1 knockdown predisposed RPE cells to apoptosis, aggravated mitochondrial damage, and repressed mitochondrial biogenesis after treatment with atRAL. Immunofluoresent staining and immunoprecipitation analysis confirmed that SHP-1 interacted with the endoplasmic reticulum-resident STING and suppressed K63-linked ubiquitination and activation of STING. Inhibition of STING with the specific antagonist H151 attenuated the effects of SHP-1 knockdown on mitochondrial biogenesis and oxidative damage. The adenosine monophosphate-activated protein kinase (AMPK) pathway acted as the crucial downstream target of STING and was involved in the regulatory processes.
CONCLUSIONS: These findings suggest that SHP-1 knockdown potentiates STING overactivation and represses mitochondrial biogenesis and cell survival, at least in part by blocking the AMPK pathway in RPE cells. Therefore, restoring mitochondrial health by regulating SHP-1 in RPE cells may be a potential therapeutic strategy for degenerative retinal diseases including AMD.

Keywords:  Adenosine monophosphate-activated protein kinase; Age-related macular degeneration; All trans retinal; Mitochondrial biogenesis; Retinal pigment epithelium; Src-homology 2 domain-containing phosphatase-1; Stimulator of interferon genes

DOI:  https://doi.org/10.1186/s10020-022-00554-w
Front Pharmacol. 2022 ;13 928853

Effects of metformin on Sonic hedgehog subgroup medulloblastoma progression: In vitro and in vivo studies.

Huangyi Fang, Lingfei Wang, Lisheng Yu, Fang Shen, Zelin Yang, Yue Yang, Shize Li, Haipeng Dai, Feng Tan, Jian Lin, Hansong Sheng.

  Metformin is a first-line drug for type 2 diabetes, and its anticancer effects have also been widely studied in recent years. The Sonic hedgehog (Shh) signaling pathway is involved in the initiation and progression of medulloblastoma. In order to develop a new treatment strategy for medulloblastoma (MB), this study investigated the inhibitory effect of metformin on MB and the underlying mechanism of metformin on the Shh signaling pathway. The effect of metformin on proliferation was evaluated by the cell counting kit-8 (CCK-8) test and colony formation experiment. The effect of metformin on metastasis was assessed by the scratch-wound assay and transwell invasion assay. Cell cycle and apoptosis were evaluated by flow cytometry, and the associated proteins were examined by western blotting. The mRNA and protein expression levels related to the Shh pathway were measured by quantitative PCR, western blotting, and immunofluorescence staining. The xenograft murine model was carried out to evaluate the anticancer effect of metformin on medulloblastoma in vivo. Metformin inhibited proliferation and metastasis of the Shh subgroup MB cell line, and the inhibitory effect on proliferation was related to apoptosis and the block of the cell cycle at the G0/G1 phase. Animal experiments showed that metformin inhibits medulloblastoma growth in vivo. Moreover, metformin decreased mRNA and protein expression levels of the Shh pathway, and this effect was reversed by the AMP-activated protein kinase (AMPK) siRNA. Furthermore, the pro-apoptotic and cell cycle arrest effects of metformin on Daoy cells could be reversed by the Shh pathway activators. Our findings demonstrated that metformin could inhibit medulloblastoma progression in vitro and in vivo, and this effect was associated with AMPK-mediated inhibition of the Shh signaling pathway in vitro studies.

Keywords:  AMPK; Sonic hedgehog signaling pathway; anticancer; medulloblastoma; metformin

DOI:  https://doi.org/10.3389/fphar.2022.928853
J Physiol Pharmacol. 2022 Jun;73(3):

Adenosine diphosphate-ribosylation factor-like 15 can regulate glycolysis and lipogenesis related genes in colon cancer.

F Du, H-J Zhang, W Shao, Y-Y Tu, K-J Yang, L-S Piao.

This study was designed to investigate the potential key genes of ADP-ribosylation factor-like 15 (ARL15) regulating glycolysis and lipogenesis in colon cancer. Hematoxylin-eosin (HE) staining and immunohistochemistry were used to observe the expression of ARL15 in 10 normal colon tissues and 10 colon cancer tissues. Immunofluorescence staining was used to observe the expression position of ARL15 in normal human colorectal mucosa cells (FHC) and colon cancer cells (HCT116 and SW620) with a confocal microscope. The ARL15 plasmid and small interfering RNA (siRNA) were constructed. After transfection, the expression levels of glycolysis and lipogenesis regulatory enzymes and messenger RNA (mRNA) transcription of ARL15 in over-expressed and silenced colon cancer cells were detected by Western blotting and real-time quantitative PCR (qRT-PCR). High expression of ARL15 in colon cancer tissue and low expression in normal colon tissue, and all expression are in the cytosol. The expression position of ARL15 in the FHC, HCT116, and SW620 cells was consistent and mainly distributed in the cytosol. After the pCMV-3Tag-2-ARL15 plasmid was transfected in HCT116, the protein expressions of FASN, AKT, P-AKT, P-GSK, SREBP-1 (p125) (p<0.01), and AMPK (p<0.001) were higher than those in the control group. The mRNA transcription level of FASN, GSK, AMPKa1, and SREBP-1 gene was higher than control group after the over-expression of ARL15. After the ARL15-siRNA was transfected in HCT116, the protein expression levels of PKM2, PFK, FASN, AKT, P-AKT, P-GSK, and AMPK decreased compared with the control group, (p<0.05). The mRNA transcription level of FASN, GSK, AMPKα1 gene was lower than control group after the low-expression of ARL15 (p<0.05). After adding 2 μM JIB-04, ARL15 in HCT116 showed statistical differences compared with the control group at 12 h, 24 h and 36 h (p<0.05). After adding 2 μM JIB-04, the protein expression levels of AKT, p-GSK, FASN, AMPK and SREBP-1 in HCT116 cells decreased significantly after 24 h. It was also found that the expression levels of AKT, P-GSK, FASN, AMPK and SREBP-1 genes in the dose-adding group were significantly lower than those in the control group. In summary, ARL15 may promote the occurrence of colon cancer by increasing the expression of protein kinase B/AMP-activated protein kinase (AKT/AMPK) downstream regulatory enzymes for glycogenesis and lipogenesis. JIB-04 can target ARL15 and affect its expression as well as the expressions of glucose and lipid metabolity-related proteins in AKT and AMPK signaling pathways.

DOI: https://doi.org/10.26402/jpp.2022.3.08
Oncol Rep. 2022 Dec;pii: 219. [Epub ahead of print]48(6):

PEDF inhibits non‑small cell lung cancer proliferation by suppressing autophagy through downregulation of AMPK‑ULK1 signaling.

Haoran Miao, Hongliang Hui, Huaming Li, Yangui Lin, Dan Li, Min Luo, Bo Jiang, Yiqian Zhang.

  Current investigations suggest that pigment epithelial‑derived factor (PEDF) can mediate the progression of non‑small cell lung cancer (NSCLC) by regulating autophagy. However, the underlying mechanisms associated with autophagy remain poorly elucidated. The aim of the present study was to investigate the association between the PEDF/adenosine 5'‑monophosphate‑activated protein kinase (AMPK)/Unc‑51 like autophagy‑activated kinase 1 (ULK1) pathway and autophagy in NSCLC. Intracellular autophagy was evaluated using indicators such as the expression and activation of microtubule‑associated protein light chain 3‑I (LC3‑I), LC3‑II and p62, as well as the distribution and number of autophagosomes observed by confocal microscopy. In addition, the activity and proliferative capacity of NSCLC cells under PEDF overexpression was also examined using Cell Counting Kit‑8 and lactate dehydrogenase (LDH) assays, and western blotting (WB) of related proteins. The results revealed that PEDF significantly inhibited NSCLC cell proliferation and viability, and increased LDH release and intercellular adhesion. Furthermore, PEDF suppressed the expression and activation of LC‑3 and reduced the number and distribution of autophagosomes. The PEDF‑induced inhibition of autophagy exhibited a direct association with the suppressed proliferation capacity and cell viability of NSCLC cells. The results of WB showed that NSCLC cells regulated autophagy through the AMPK/ULK1 signaling pathway. PEDF downregulated the AMPK/ULK1 signaling pathway, and AMPK or ULK1 overexpression markedly reduced the inhibitory effect of PEDF on autophagy. In conclusion, PEDF overexpression significantly inhibited the proliferative capacity and cell viability of NSCLC cells, as PEDF exerted an inhibitory function by regulating autophagy in NSCLC cells. Finally, it was demonstrated that autophagy may be suppressed by inhibiting the AMPK/ULK1 signaling pathway, thereby revealing a mechanism of lung cancer progression.

Keywords:  autophagy; non‑small cell lung cancer; pigment epithelium‑derived factor; proliferation

DOI:  https://doi.org/10.3892/or.2022.8434
J Diabetes Investig. 2022 Oct 28.

New mechanism of metformin action mediated by lysosomal presenilin enhancer 2.

Kenji Sugawara, Wataru Ogawa.

Formation of the PEN2-ATP6AP1 complex induced by the binding of metformin to PEN2 results in the inhibition of v-ATPase activity and in the recruitment of AXIN/LKB1 to lysosomes, which in turn results in the phosphorylation and activation of AMPK.

DOI: https://doi.org/10.1111/jdi.13925
Neurosci Lett. 2022 Oct 22. pii: S0304-3940(22)00494-3. [Epub ahead of print] 136933

Dexmedetomidine alleviates pain in MPTP-treated mice by activating the AMPK/mTOR/NF-κB pathways in astrocytes.

Yaohua Chen, Yuping Li, Chunxiang Li, Dan Zhu, Oumei Cheng, Jian Cui.

  Pain is a major non-motor symptom that contributes to impaired quality of life in Parkinson's disease (PD). However, the mechanisms and treatment of pain in PD have not been well studied. Dexmedetomidine (Dex) is used for analgesia and sedation during deep brain stimulation (DBS) and may reverse the progression of PD. Here, we explored the effect of Dex on Parkinson's pain and the underlying mechanism. C57BL/6 mice were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg) to establish a PD model. Then, the mice were treated with Dex (50 µg/kg) or Compound C (CC, 10 mg/kg, AMPK inhibitor). A motor behavioral test was used to validate the PD model, and a plantar test was conducted to assess mechanical and thermal stimulation thresholds. Immunofluorescence and western blotting were used to analyze the level of tyrosine hydroxylase (TH) in the substantia nigra (SN) and the expression of c-Fos, GFAP, p-AMPK, mTOR, NF-κB, TNFα, and IL-6 in the dorsal horn of the spinal cord (DHSC). We found that mice exhibited motor dysfunction and mechanical allodynia and thermal hyperalgesia after MPTP injection, and these changes were partially reversed by Dex. Dex also reduced MPTP-induced astrocyte activation and TNFα and IL-6 expression, increased p-AMPK and reduced mTOR and NF-κB expression in DHSC. Moreover, the effects of Dex were partially reversed by the AMPK inhibitor Compound C. Conclusions: These findings reveal that Dex protects dopaminergic neurons in PD and alleviates pain by reducing the activation of DHSC astrocytes through the AMPK/mTOR/NF-κB pathway. Therefore, Dex may be a potential drug for treating Parkinson's pain.

Keywords:  Parkinson's disease; astrocyte; dexmedetomidine; dorsal horn of the spinal cord; pain

DOI:  https://doi.org/10.1016/j.neulet.2022.136933
Cell Immunol. 2022 Oct 15. pii: S0008-8749(22)00156-3. [Epub ahead of print]382 104631

Narciclasine ameliorated T cell mediated acute liver injury through activating AMPK pathway.

Yuanyuan Tian, Jiao Wang, Xiaori Qin, Shibing Li, Cheng Lan, Xiaoning Sun.

  Hepatitis is closely related to cirrhosis and liver cancer, and it is vital that we develop new drugs and identify new drug targets. Traditional Chinese medicine has demonstrated excellent curative effects on liver diseases. The ingredients from Chinese herbals are important source for drug development in the treatment of hepatitis. Here, we found that narciclasine (NCS), a major component extracted from narcissus bulbs, showed hepatoprotective effect against concanavalin A (Con A) induced hepatitis. NCS treatment significantly reduced hepatocyte death, hepatic inflammatory cells infiltration, and serum cytokine levels in Con A challenged mice. We further observed that NCS directly inhibited Con A induced splenocytes proliferation and cytokine production in vitro. RNA-seq results showed that genes related to immune response were upregulated in Con A treated CD4+ T cells, which were down-regulated in the presence of NCS. Moreover, the AMPK pathway had been found activated in response to NCS treatment, suggesting a potential target for NCS targets. In conclusion, our results reveal that NCS is a powerful immunosuppressor against T cell activation, thus leading to protection against Con A induced liver injury in mice. These findings provide new insights into the use of natural products in the treatment of autoimmune hepatitis.

Keywords:  AMPK; Liver injury; Narciclasine; T cells; concanavalin A

DOI:  https://doi.org/10.1016/j.cellimm.2022.104631
Stem Cell Rev Rep. 2022 Oct 29.

hUMSCs Transplantation Regulates AMPK/NR4A1 Signaling Axis to Inhibit Ovarian Fibrosis in POI Rats.

Linlu Cui, Hongchu Bao, Wenqian Zhu, Yu Tang, Qianqian Luo, Yaru Si, Qiang Fu, Zhonglin Jiang.

  BACKGROUND: The mechanism of human Umbilical Cord Mesenchymal Stem Cells (hUMSCs) transplantation to improve ovarian function in the rats with Premature Ovarian Insufficiency (POI) is still unclear. The aim of this study is to investigate the signal axis mechanism that is involved in the ovarian function recovery of POI rats following hUMSCs transplantation.METHODS: The rat model with POI was established by intraperitoneal injection of cisplatin. The hUMSCs were transplanted by caudal vein injection into POI rats. Hematoxylin-eosin (H&E) staining was performed to examine the morphology of rat ovarian tissue. Masson staining, Sirus red staining and immunofluorescence were used to observe the fibrosis extent of ovarian tissue. The levels of serum sex hormones and the expression of fibrosis related markers in ovarian tissues were measured by enzyme-linked immunosorbent assay (ELISA). The expression of NR4A1, Phospho-NR4A1 and AMP-activated protein kinase (AMPK) signaling in rat ovarian tissues was measured by immunohistochemistry and immunofluorescence. The role of AMPK/NR4A1 signaling axis in the regulation of ovarian function recovery in POI rats following hUMSCs transplantation was further investigated by adenovirus and siRNA intervention in isolated stromal cells.
RESULTS: The results showed that the hUMSCs transplantation significantly inhibited ovarian tissue fibrosis and restored the ovarian function in POI rats. The level of NR4A1 and AMPK expression in ovarian tissue of POI rats after hUMSCs transplantation was significantly increased compared with the control group. In the cultured ovarian stromal cells, the similar results were obtained on the expression of NR4A1 and its regulation on fibrosis related molecular markers in Cisplatin (CDDP) damaged stromal cells following hUMSCs supernatant treatment. Both hUMSCs supernatant treatment and the addition of AMPK inhibitors increased NR4A1 expression in stromal cells. And after NR4A1 molecular intervention, fibrosis-related indicators in stromal cells changed. The data suggests that the AMPK/NR4A1 signaling axis is involved in the ovarian function changes in POI rats following hUMSCs transplantation.
CONCLUSION: The data from this study indicate that the inhibition of tissue fibrosis and recovery of ovarian function is regulated by AMPK/NR4A1 signaling axis in POI rats following hUMSCs transplantation.

Keywords:  Fibrosis; Human umbilical cord—derived mesenchymal stem cells; NR4A1; Ovarian stromal cells; Premature ovarian insufficiency

DOI:  https://doi.org/10.1007/s12015-022-10469-y
Cell Death Dis. 2022 Oct 27. 13(10): 902

IKCa channels control breast cancer metabolism including AMPK-driven autophagy.

Dominic Gross, Helmut Bischof, Selina Maier, Katharina Sporbeck, Andreas L Birkenfeld, Roland Malli, Peter Ruth, Tassula Proikas-Cezanne, Robert Lukowski.

Ca2+-activated K+ channels of intermediate conductance (IK) are frequently overexpressed in breast cancer (BC) cells, while IK channel depletion reduces BC cell proliferation and tumorigenesis. This raises the question, of whether and mechanistically how IK activity interferes with the metabolic activity and energy consumption rates, which are fundamental for rapidly growing cells. Using BC cells obtained from MMTV-PyMT tumor-bearing mice, we show that both, glycolysis and mitochondrial ATP-production are reduced in cells derived from IK-deficient breast tumors. Loss of IK altered the sub-/cellular K+- and Ca2+- homeostasis and mitochondrial membrane potential, ultimately resulting in reduced ATP-production and metabolic activity. Consequently, we find that BC cells lacking IK upregulate AMP-activated protein kinase activity to induce autophagy compensating the glycolytic and mitochondrial energy shortage. Our results emphasize that IK by modulating cellular Ca2+- and K+-dynamics contributes to the remodeling of metabolic pathways in cancer. Thus, targeting IK channel might disturb the metabolic activity of BC cells and reduce malignancy.

DOI: https://doi.org/10.1038/s41419-022-05329-z
Theranostics. 2022 ;12(16): 7158-7179

A new LKB1 activator, piericidin analogue S14, retards renal fibrosis through promoting autophagy and mitochondrial homeostasis in renal tubular epithelial cells.

Canzhen Liu, Xiaoxu Wang, Xiaonan Wang, Yunfang Zhang, Wenjian Min, Ping Yu, Jinhua Miao, Weiwei Shen, Shuangqin Chen, Shan Zhou, Xiaolong Li, Ping Meng, Qinyu Wu, Fan Fan Hou, Youhua Liu, Peng Yang, Cheng Wang, Xu Lin, Lan Tang, Xuefeng Zhou, Lili Zhou.

  Background: Liver kinase B1 (LKB1) is the key regulator of energy metabolism and cell homeostasis. LKB1 dysfunction plays a key role in renal fibrosis. However, LKB1 activators are scarce in commercial nowadays. This study aims to discover a new drug molecule, piericidin analogue S14 (PA-S14), preventing renal fibrosis as a novel activator to LKB1. Methods: Our group isolated PA-S14 from the broth culture of a marine-derived Streptomyces strain and identified its binding site. We adopted various CKD models or AKI-CKD model (5/6 nephrectomy, UUO, UIRI and adriamycin nephropathy models). TGF-β-stimulated renal tubular cell culture was also tested. Results: We identified that PA-S14 binds with residue D176 in the kinase domain of LKB1, and then induces the activation of LKB1 through its phosphorylation and complex formation with MO25 and STRAD. As a result, PA-S14 promotes AMPK activation, triggers autophagosome maturation, and increases autophagic flux. PA-S14 inhibited tubular cell senescence and retarded fibrogenesis through activation of LKB1/AMPK signaling. Transcriptomics sequencing and mutation analysis further demonstrated our results. Conclusion: PA-S14 is a novel leading compound of LKB1 activator. PA-S14 is a therapeutic potential to renal fibrosis through LKB1/AMPK-mediated autophagy and mitochondrial homeostasis pathways.

Keywords:  AMPK; LKB1; PA-S14; autophagy; renal fibrosis

DOI:  https://doi.org/10.7150/thno.78376
Hormones (Athens). 2022 Oct 27.

Alpha-lipoic acid activates AMPK to protect against oxidative stress and apoptosis in rats with diabetic peripheral neuropathy.

Tianya Zhang, Dong Zhang, Zhihong Zhang, Jiaxin Tian, Jingwen An, Wang Zhang, Ying Ben.

  PURPOSE: To investigate the AMPK pathway-mediated effect of alpha-lipoic acid (ALA) on the dorsal root ganglia (DRGs) of rats with diabetic peripheral neuropathy (DPN) and to attempt to elucidate the underlying mechanism.METHODS: Sprague-Dawley rats (n = 15) were randomly divided into three groups. The control group was fed a standard diet, and the other groups were fed a high-carbohydrate/high-fat diet. Diabetes was established by a single streptozotocin (STZ) (30 mg/kg) injection, and control rats were injected with an equal volume of citrate buffer. ALA (60 mg/kg/day) was administered for 12 weeks. The nerve conduction velocity (NCV) of the sciatic nerve was measured. Glutathione (GSH) and malondialdehyde (MDA) concentrations in serum were measured with the thiobarbituric acid method and biochemistry. Pathological changes in the rat DRGs were observed. AMPK, phospho-AMPK (p-AMPK), nuclear factor erythroid-2-related factor 2 (Nrf2), phospho-nuclear factor erythroid-2-related factor 2 (p-Nrf2), heme oxygenase 1 (HO-1), quinone oxidoreductase 1 (NQO1), Forkhead box O3 (FoxO3a), phospho-Forkhead box O3 (p-FoxO3a), and Bcl-2 interacting mediator of cell death (Bim) expression levels were assessed by immunohistochemistry and western blotting.
RESULTS: ALA improved the motor NCV (MNCV) and sensory NCV (SNCV) of rats with DPN and reduced their mechanical pain threshold. ALA increased serum GSH concentrations and decreased serum MDA concentrations. Additionally, AMPK was activated by ALA. Nrf2, p-Nrf2, HO-1, and NQO1 expression was upregulated, while FoxO3a, p-FoxO3a, and Bim expression was downregulated. ALA reduced oxidative stress and apoptosis in DRG.
CONCLUSION: ALA alleviates DPN and improves peripheral nerve function. ALA reduces oxidative stress by activating Nrf2 through AMPK and inhibits FoxO3a and Bim thereby reducing neuronal apoptosis.

Keywords:  Alpha-lipoic acid; Apoptosis; Diabetic peripheral neuropathy; Dorsal root ganglia; Oxidative stress

DOI:  https://doi.org/10.1007/s42000-022-00413-7
Pharmaceuticals (Basel). 2022 Oct 17. pii: 1274. [Epub ahead of print]15(10):

The Potential Therapeutic Role of Metformin in Diabetic and Non-Diabetic Bone Impairment.

Wei Mu, Guoqiang Liang, Yue Feng, Yunyun Jiang, Falin Qu.

  Metformin is a widely-used anti-diabetic drug in patients with type 2 diabetic mellitus (T2DM) due to its safety and efficacy in clinical. The classic effect of metformin on lowering blood glucose levels is to inhibit liver gluconeogenesis that reduces glucose production as well as increases peripheral glucose utilization. However, the factors such as hyperglycemia, insulin deficiency, reduced serum levels of insulin-like growth factor-1 (IGF-1) and osteocalcin, accumulation of advanced glycation end products (AGEs), especially in collagen, microangiopathy, and inflammation reduced bone quality in diabetic patients. However, hyperglycemia, insulin deficiency, reduced levels of insulin-like growth factor-1 (IGF-1) and osteocalcin in serum, accumulation of advanced glycation end products (AGEs) in collagen, microangiopathy, and inflammation, reduce bone quality in diabetic patients. Furthermore, the imbalance of AGE/RAGE results in bone fragility via attenuating osteogenesis. Thus, adequate glycemic control by medical intervention is necessary to prevent bone tissue alterations in diabetic patients. Metformin mainly activates adenosine 5' -monophosphate-activated protein kinase (AMPK), and inhibits mitochondrial respiratory chain complex I in bone metabolism. In addition, metformin increases the expression of transcription factor runt-related transcription factor2 (RUNX2) and Sirtuin protein to regulate related gene expression in bone formation. Until now, there are a lot of preclinical or clinical findings on the application of metformin to promote bone repair. Taken together, metformin is considered as a potential medication for adjuvant therapy in bone metabolic disorders further to its antidiabetic effect. Taken together, as a conventional hypoglycemia drug with multifaceted effects, metformin has been considered a potential adjuvant drug for the treatment of bone metabolic disorders.

Keywords:  AGEs; AMPK; RUNX2; metformin; osteogenesis

DOI:  https://doi.org/10.3390/ph15101274
Metabolism. 2022 Oct 19. pii: S0026-0495(22)00213-X. [Epub ahead of print] 155335

Modulation of hypothalamic AMPK phosphorylation by olanzapine controls energy balance and body weight.

Vítor Ferreira, Cintia Folgueira, Maria Guillén, Pablo Zubiaur, Marcos Navares, Assel Sarsenbayeva, Pilar López Larrubia, Jan W Eriksson, Maria J Pereira, Francisco Abad-Santos, Guadalupe Sabio, Patricia Rada, Ángela M Valverde.

  BACKGROUND: Second-generation antipsychotics (SGAs) are a mainstay therapy for schizophrenia. SGA-treated patients present higher risk for weight gain, dyslipidemia and hyperglycemia. Herein, we evaluated the effects of olanzapine (OLA), widely prescribed SGA, in mice focusing on changes in body weight and energy balance. We further explored OLA effects in protein tyrosine phosphatase-1B deficient (PTP1B-KO) mice, a preclinical model of leptin hypersensitivity protected against obesity.METHODS: Wild-type (WT) and PTP1B-KO mice were fed an OLA-supplemented diet (5 mg/kg/day, 7 months) or treated with OLA via intraperitoneal (i.p.) injection or by oral gavage (10 mg/kg/day, 8 weeks). Readouts of the crosstalk between hypothalamus and brown or subcutaneous white adipose tissue (BAT and iWAT, respectively) were assessed. The effects of intrahypothalamic administration of OLA with adenoviruses expressing constitutive active AMPKα1 in mice were also analyzed.
RESULTS: Both WT and PTP1B-KO mice receiving OLA-supplemented diet presented hyperphagia, but weight gain was enhanced only in WT mice. Unexpectedly, all mice receiving OLA via i.p. lost weight without changes in food intake, but with increased energy expenditure (EE). In these mice, reduced hypothalamic AMPK phosphorylation concurred with elevations in UCP-1 and temperature in BAT. These effects were also found by intrahypothalamic OLA injection and were abolished by constitutive activation of AMPK in the hypothalamus. Additionally, OLA i.p. treatment was associated with enhanced Tyrosine Hydroxylase (TH)-positive innervation and less sympathetic neuron-associated macrophages in iWAT. Both central and i.p. OLA injections increased UCP-1 and TH in iWAT, an effect also prevented by hypothalamic AMPK activation. By contrast, in mice fed an OLA-supplemented diet, BAT thermogenesis was only enhanced in those lacking PTP1B. Our results shed light for the first time that a threshold of OLA levels reaching the hypothalamus is required to activate the hypothalamus BAT/iWAT axis and, therefore, avoid weight gain.
CONCLUSION: Our results have unraveled an unexpected metabolic rewiring controlled by hypothalamic AMPK that avoids weight gain in male mice treated i.p. with OLA by activating BAT thermogenesis and iWAT browning and a potential benefit of PTP1B inhibition against OLA-induced weight gain upon oral treatment.

Keywords:  Adipose tissue; Hypothalamus; Inter-organ crosstalk; Olanzapine; Sympathetic innervation; Thermogenesis

DOI:  https://doi.org/10.1016/j.metabol.2022.155335
J Immunol. 2022 Oct 24. pii: ji2200182. [Epub ahead of print]

FABP5 Deficiency Impaired Macrophage Inflammation by Regulating AMPK/NF-κB Signaling Pathway.

Yangxiao Hou, Dong Wei, Elhusseny A Bossila, Zhaoqi Zhang, Sihong Li, Jiaming Bao, Huawen Xu, Lianfeng Zhang, Yong Zhao.

Fatty acid binding protein 5 (FABP5) is mainly involved in the uptake, transport, and metabolism of fatty acid in the cytoplasm, and its role in immune cells has been recognized in recent years. However, the role of FABP5 in macrophage inflammation and its underlying mechanisms were not fully addressed. In our study, the acute liver injury and sepsis mouse models were induced by i.p. injection of LPS and cecal contents, respectively. Oleic acid (0.6 g/kg) was injected four times by intragastric administration every week, and this lasted for 1 wk before the LPS or cecal content challenge. We found that myeloid-specific deletion of FABP5 mitigated LPS-induced acute liver injury with reduced mortality of mice, histological liver damage, alanine aminotransferase, and proinflammatory factor levels. Metabolic analysis showed that FABP5 deletion increased the intracellular unsaturated fatty acids, especially oleic acid, in LPS-induced macrophages. The addition of oleic acid also decreased LPS-stimulated macrophage inflammation in vitro and reduced acute liver injury in LPS-induced or cecal content-induced sepsis mice. RNA-sequencing and molecular mechanism studies showed that FABP5 deletion or oleic acid supplementation increased the AMP/ATP ratio and AMP-activated protein kinase (AMPK) activation and inhibited the NF-κB pathway during the inflammatory response to LPS stimulation of macrophages. Inhibiting AMPK activation or expression by chemical or genetic approaches significantly rescued the decreased NF-κB signaling pathway and inflammatory response in LPS-treated FABP5-knockout macrophages. Our present study indicated that inhibiting FABP5 or supplementation of oleic acid might be used for the treatment of sepsis-caused acute liver injury.

DOI: https://doi.org/10.4049/jimmunol.2200182
Exp Ther Med. 2022 Nov;24(5): 694

Thymoquinone‑induced autophagy mitigates doxorubicin‑induced H9c2 cell apoptosis.

Dawei Liu, Lei Zhao.

  Doxorubicin (Dox)-induced myocardiopathy is a massive obstacle in administering chemotherapeutic drugs in cancer patients. In the present study, the effects of thymoquinone (TQ) on Dox-induced cardiotoxicity were investigated in vitro. H9c2 cardiomyocytes were pre-treated with TQ followed by Dox, and cell viability and cell death were subsequently measured. Flow cytometry was conducted to evaluate the apoptosis of H9c2 cells. Autophagy was assessed by immunofluorescence LC3 staining. Western blot analysis was performed to determine autophagy-, apoptosis- and LKB1/AMPK-related proteins. Dox-induced H9c2 cell death and apoptosis were decreased after pretreatment with TQ in vitro. The number of autophagosomes and autophagic markers was further increased by TQ in the Dox-treated H9c2 cells, which mediated LKB1/AMPK activation and the deactivation of mTOR. Suppression of autophagosomes abolished the TQ-induced antiapoptotic effect. In conclusion, TQ reduces Dox-induced apoptosis of cardiomyocytes by upregulating autophagy through activation of the LKB1/AMPK pathways. These novel results highlight the therapeutic potential of TQ to prevent Dox cardiotoxicity.

Keywords:  AMPK; apoptosis; autophagy; doxorubicin-induced cardiotoxicity; thymoquinone

DOI:  https://doi.org/10.3892/etm.2022.11630
Cell Mol Life Sci. 2022 Oct 29. 79(11): 573

Mfn2-mediated mitochondrial fusion promotes autophagy and suppresses ovarian cancer progression by reducing ROS through AMPK/mTOR/ERK signaling.

Rahail Ashraf, Sanjay Kumar.

  Mitochondrial dynamics are balanced fission and fusion events that regulate mitochondrial morphology, and alteration in these events results in mitochondrial dysfunction and contributes to many diseases, including tumorigenesis. Ovarian cancer (OC) cells exhibit fragmented mitochondria, but the mechanism by which mitochondrial dynamics regulators contribute to OC is considerably less clear. Here, we elucidated the potential role of Mfn2-mediated mitochondrial fusion in OC and present evidence that genetic or pharmacological activation of Mfn2 leads to mitochondrial fusion and reduces ROS generation, which correlates with reduced cell proliferation, invasion, migration, and EMT in OC cells. Also, increased mitochondrial fusion promotes the F-actin remodeling, reduces lamellipodia formation, and thus reduces EMT. Increased expression of Mfn2 triggers AMPK, promotes autophagy, reduces ROS, and suppresses OC progression by downregulating the p-mTOR (2481 and 2448) and p-ERK axis. OC patients with higher Mfn2 expression have better survival than those with lower Mfn2 levels. Our findings demonstrate that restoration of Mfn2-mediated mitochondrial fusion suppressed OC progression and suggest that this process could be a potential strategy in OC treatment.

Keywords:  AMPK; Autophagy; EMT; Mfn2; Ovarian cancer; ROS

DOI:  https://doi.org/10.1007/s00018-022-04595-6
Front Mol Neurosci. 2022 ;15 978191

Deficiency of miR-29a/b1 leads to premature aging and dopaminergic neuroprotection in mice.

Xiaochen Bai, Jinghui Wang, Xiaoshuang Zhang, Yilin Tang, Yongtao He, Jiayin Zhao, Linlin Han, Rong Fang, Zhaolin Liu, Hongtian Dong, Qing Li, Jingyu Ge, Yuanyuan Ma, Mei Yu, Ruilin Sun, Jian Wang, Jian Fei, Fang Huang.

  Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of midbrain dopaminergic neurons. The miR-29s family, including miR-29a and miR-29b1 as well as miR-29b2 and miR-29c, are implicated in aging, metabolism, neuronal survival, and neurological disorders. In this study, the roles of miR-29a/b1 in aging and PD were investigated. miR-29a/b1 knockout mice (named as 29a KO hereafter) and their wild-type (WT) controls were used to analyze aging-related phenotypes. After challenged with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), dopaminergic injuries, glial activation, and mouse behaviors were evaluated. Primary glial cells were further cultured to explore the underlying mechanisms. Additionally, the levels of miR-29s in the cerebrospinal fluid (CSF) of PD patients (n = 18) and healthy subjects (n = 17) were quantified. 29a KO mice showed dramatic weight loss, kyphosis, and along with increased and deepened wrinkles in skins, when compared with WT mice. Moreover, both abdominal and brown adipose tissues reduced in 29a KO mice, compared to their WT counterpart. However, in MPTP-induced PD mouse model, the deficiency of miR-29a/b1 led to less severe damages of dopaminergic system and mitigated glial activation in the nigrostriatal pathway, and subsequently alleviated the motor impairments in 3-month-old mice. Eight-month-old mutant mice maintained such a resistance to MPTP intoxication. Mechanistically, the deficiency of miR-29a/b-1 promoted the expression of neurotrophic factors in 1-Methyl-4-phenylpyridinium (MPP+)-treated primary mixed glia and primary astrocytes. In lipopolysaccharide (LPS)-treated primary microglia, knockout of miR-29a/b-1 inhibited the expression of inflammatory factors, and promoted the expression of anti-inflammatory factors and neurotrophic factors. Knockout of miR-29a/b1 increased the activity of AMP-activated protein kinase (AMPK) and repressed NF-κB/p65 signaling in glial cells. Moreover, we found miR-29a level was increased in the CSF of patients with PD. Our results suggest that 29a KO mice display the peripheral premature senility. The combined effects of less activated glial cells might contribute to the mitigated inflammatory responses and elicit resistance to MPTP intoxication in miR-29a/b1 KO mice.

Keywords:  AMPK; Parkinson’s disease; glial cells; miR-29a/b1; neuroinflammation

DOI:  https://doi.org/10.3389/fnmol.2022.978191