scholarly journals Neferine Enhances Autophagy to Alleviate Cytotoxicity and Apoptosis Induced by CSE in AEC-II through AMPK/mTOR Signaling Pathway

2020 ◽  
Author(s):  
Mengmeng Wang ◽  
Haiyang Yu ◽  
Yuqing Sun ◽  
Pengpeng Cheng ◽  
Qian Wang ◽  
...  
Keyword(s):  
Protective Effect ◽  
Signaling Pathway ◽  
Cell Model ◽  
Cell Damage ◽  
Case Fatality ◽  
Chronic Respiratory Disease ◽  
Mtor Signaling ◽  
Autophagic Flux ◽  
Mtor Signaling Pathway ◽  
Compound C

Abstract COPD is a clinical common chronic respiratory disease, its incidence case fatality rate is higher, there is currently no cure drugs and methods. In this study, in order to make clear its role in the development of autophagy in COPD, COPD cell model is established.To further explore whether regulating autophagy could have a protective effect to fight against CSE-induced cytotoxicity and apoptosis, we choose neferine as an autophagy inducer. Neferine activated cell autophagy in an vitro CSE-induced COPD cell model and gradually attenuated CSE-induced cell apoptosis. Furthermore, this process happens largely through the AMPK/mTOR signaling pathway. As a autophagic flux inhibitor, chloroquine abolished the prosurvival autophagy effect, and AMPK inhibitor Compound C blocked neferine-mediated autophagy and then neferine failed to protect COPD cell model from CSE-induced apoptosis. Overall,our findings suggested that neferine possibly has a potentially protective effect in cell damage mechanisms caused by CSE. It hints that neferine has the prospect of turning into a potential therapeutics to cure CSE-induced cytotoxicity and apoptosis and even COPD patients.

scholarly journals Autophagy protects gastric mucosal epithelial cells from ethanol-induced oxidative damage via mTOR signaling pathway

2017 ◽  
Vol 242 (10) ◽  
pp. 1025-1033 ◽  
Author(s):  
Weilong Chang ◽  
Jie Bai ◽  
Shaobo Tian ◽  
Muyuan Ma ◽  
Wei Li ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Epithelial Cells ◽  
Oxidative Damage ◽  
Signaling Pathway ◽  
Cell Damage ◽  
Mtor Signaling ◽  
Adaptive Mechanism ◽  
Mtor Signaling Pathway ◽  
Mucosal Epithelial Cell ◽  
Ethanol Toxicity

Alcohol abuse is an important cause of gastric mucosal epithelial cell injury and gastric ulcers. A number of studies have demonstrated that autophagy, an evolutionarily conserved cellular mechanism, has a protective effect on cell survival. However, it is not known whether autophagy can protect gastric mucosal epithelial cells against the toxic effects of ethanol. In the present study, gastric mucosal epithelial cells (GES-1 cells) and Wistar rats were treated with ethanol to detect the adaptive response of autophagy. Our results demonstrated that ethanol exposure induced gastric mucosal epithelial cell damage, which was accompanied by the downregulation of mTOR signaling pathway and activation of autophagy. Suppression of autophagy with pharmacological agents resulted in a significant increase of GES-1 cell apoptosis and gastric mucosa injury, suggesting that autophagy could protect cells from ethanol toxicity. Furthermore, we evaluated the cellular oxidative stress response following ethanol treatment and found that autophagy induced by ethanol inhibited generation of reactive oxygen species and degradation of antioxidant and lipid peroxidation. In conclusion, these findings provide evidence that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate oxidative damage induced by ethanol in gastric mucosal epithelial cells. Therefore, modifying autophagy may provide a therapeutic strategy against alcoholic gastric mucosa injury. Impact statement The effect and mechanism of autophagy on ethanol-induced cell damage remain controversial. In this manuscript, we report the results of our study demonstrating that autophagy can protect gastric mucosal epithelial cells against ethanol toxicity in vitro and in vivo. We have shown that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate ethanol-induced oxidative damage in gastric mucosal epithelial cells. This study brings new and important insights into the mechanism of alcoholic gastric mucosal injury and may provide an avenue for future therapeutic strategies.

scholarly journals (Pro)renin receptor regulates autophagy and apoptosis in podocytes exposed to high glucose

2015 ◽  
Vol 309 (3) ◽  
pp. E302-E310 ◽  
Author(s):  
Caixia Li ◽  
Helmy M. Siragy
Keyword(s):  
Signaling Pathway ◽  
High Glucose ◽  
Caspase 3 ◽  
Mtor Signaling ◽  
Autophagic Flux ◽  
Bafilomycin A1 ◽  
Mtor Signaling Pathway ◽  
Autophagosome Formation ◽  
Podocyte Injury ◽  
Protein Levels

High glucose reduces autophagy and enhances apoptosis of podocytes. Previously, we reported that high glucose induced podocyte injury through upregulation of the (pro)renin receptor (PRR). We hypothesized that increasing PRR reduces autophagy and increases apoptosis of mouse podocytes exposed to high glucose via activation of the PI3K/Akt/mTOR signaling pathway. Mouse podocytes were cultured in normal (5 mmol/l) or high (25 mmol/l) d-glucose for 48 h. High glucose significantly increased mRNA and protein levels of PRR, phosphorylation of PI3K/Akt/mTOR, and p62. In contrast, high glucose decreased activation of UNC-51-like kinase-1 (ULK1) by phosphorylating Ser757 and protein levels of microtubule-associated protein-1 light chain 3B (LC3B)-II and Lamp-2. Bafilomycin A1 increased LC3BII and p62 accumulation in high-glucose-treated cells. High glucose reduced the autophagic flux. Confocal microscopy studies showed significant reduction in the protein level of LC3B in response to high glucose. Cyto-ID autophagy staining showed a significant decrease in autophagosome formation with high glucose. In the absence of PRR, activation of Akt with sc-79 or mTOR with MHY-1485 increased p62 accumulation. Caspase-3/7 activity and apoptosis monitored by TUNEL assay were significantly increased in podocytes treated with high glucose. PRR siRNA significantly reversed the effects of high glucose. Based on these data, we conclude that high glucose decreases autophagy and increases apoptosis in mouse podocytes through the PRR/PI3K/Akt/mTOR signaling pathway.

Active vitamin D activates chondrocyte autophagy to reduce osteoarthritis via mediating the AMPK–mTOR signaling pathway

2020 ◽  
Vol 98 (3) ◽  
pp. 434-442 ◽  
Author(s):  
Chunyu Kong ◽  
Changlei Wang ◽  
Yuquan Shi ◽  
Lei Yan ◽  
Junhua Xu ◽  
...  
Keyword(s):  
Vitamin D ◽  
Signaling Pathway ◽  
Therapeutic Option ◽  
Serum Levels ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
Ampk Signaling ◽  
Hydroxyvitamin D ◽  
Compound C ◽  
Safranin O

Osteoarthritis (OA) is a common joint degenerative disease. Vitamin D (VD) is essential for bone health. We hypothesized that active VD could be used as a therapeutic treatment for OA. Low serum levels of 25-hydroxyvitamin D [25(OH)D] have been found in patients with OA, and thus the serum level of VD could be diagnostic of OA. To test this, we established a mouse model of OA. The results from staining with hematoxylin–eosin and Safranin O – Fast Green indicated that active VD reduced the symptoms of OA in mice. The results from Western blotting indicated that treatment with VD increased the activity of the p-AMPK–AMPK signaling pathway and decreased the p-mTOR–mTOR pathway; it also increased the ratio of LC3II:LC3I antibodies and the protein expression levels of Beclin-1, but decreased the level of p62. Further, treatment with VD reduced the levels of tumor necrosis factor-α and interleukin-6 both in cartilage tissues and in chondrocytes. Administration of the AMPK inhibitor compound C and autophagy inhibitor 3-methyladenine (3-MA) reversed these changes following VD treatment. In addition, the results from transfection with mRFP-GFP-LC3 indicated that active VD led to autophagosome aggregation in OA chondrocytes. 3-MA inhibited cell autophagy and promoted inflammation in OA. This study provides evidence that active VD activate chondrocyte autophagy to reduce OA inflammation via activating the AMPK–mTOR signaling pathway. Treatment with active VD could be a novel therapeutic option for OA.

scholarly journals NOX2-Derived Hydrogen Peroxide Impedes the AMPK/Akt-mTOR Signaling Pathway in Parkinson's Disease in Vitro Models

2021 ◽  
Author(s):  
Ruijie Zhang ◽  
Nana Zhang ◽  
Xiaoqing Dong ◽  
Xin Chen ◽  
Jing Ma ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Parkinson’S Disease ◽  
Hydrogen Peroxide ◽  
Parkinson's Disease ◽  
Signaling Pathway ◽  
Neuronal Apoptosis ◽  
Mtor Signaling ◽  
Regulatory Proteins ◽  
Mtor Signaling Pathway ◽  
Compound C

Abstract Oxidative stress is closely related to the pathogenesis of Parkinson's disease (PD), a typical neurodegenerative disease. NADPH oxidase 2 (NOX2) is involved in hydrogen peroxide (H2O2) generation. Recently, we have reported that H2O2 and PD toxins, including 6-hydroxydopamine (6-OHDA), 1-Methyl-4-phenylpyridin-1-ium (MPP+) and rotenone, induce neuronal apoptosis by inhibiting mTOR pathway. Here, we show that 6-OHDA, MPP+ or rotenone induced H2O2 generation by upregulation of NOX2 and its regulatory proteins (p22phox, p40phox, p47phox, p67phox, and Rac1), leading to apoptotic cell death in PC12 cells and primary neurons. Pretreatment with catalase, a H2O2-scavenging enzyme, significantly blocked PD toxins-evoked NOX2-derived H2O2, thereby hindering activation of AMPK, inhibition of Akt/mTOR, induction of apoptosis in neuronal cells. Similar events were also seen in the cells pretreated with Mito-TEMPO, a mitochondria-specific superoxide scavenger, implying a mitochondrial H2O2-dependent mechanism involved. Further research revealed that inhibiting NOX2 with apocynin or silencing NOX2 attenuated the effects of PD toxins on AMPK/Akt/mTOR and apoptosis in the cells. Of importance, ectopic expression of constitutively active Akt or dominant negative AMPKα, or inhibition of AMPK with compound C suppressed PD toxins-induced expression of NOX2 and its regulatory proteins, as well as consequential H2O2 and apoptosis in the cells. Taken together, these results indicate that certain PD toxins can impede the AMPK/Akt-mTOR signaling pathway leading to neuronal apoptosis by eliciting NOX2-derived H2O2. Our findings suggest that neuronal loss in PD may be prevented by regulating of NOX2, AMPK/Akt-mTOR signaling and/or administering antioxidants to ameliorate oxidative stress.

scholarly journals Roles of the pyroptosis signaling pathway in a sepsis-associated encephalopathy cell model

2020 ◽  
Vol 48 (8) ◽  
pp. 030006052094976
Author(s):  
Yan Wang ◽  
Xueyan Liu ◽  
Qiang Wang ◽  
Xin Yang
Keyword(s):  
Flow Cytometry ◽  
Protective Effect ◽  
Signaling Pathway ◽  
Cell Model ◽  
Cell Damage ◽  
Combined Treatment ◽  
Therapeutic Effects ◽  
Inhibitory Effects ◽  
Caspase Cleavage ◽  
Associated Proteins

Objectives The inhibition of pyroptosis has a protective effect in sepsis-associated encephalopathy (SAE). However, the mechanisms underlying pyroptosis in SAE remain to be elucidated. Methods Here, we investigated the effects of the caspase inhibitors, Belnacasan (Beln) and Wedelolactone (Wede), on an induced model of SAE in P12 cells, using immunofluorescence, ELISA, western blotting, and flow cytometry. Results The cell viability decreased, IL-1β and IL-18 secretion increased, and the levels of the caspase cleavage products, N-terminal gasdermin D, cleaved caspase-1, and cleaved caspase-11, increased in P12 cells following combined treatment with lipopolysaccharides (LPS) and adenosine triphosphate (ATP). However, treatment with Beln or Wede ameliorated the effects induced by LPS and ATP. Neither Beln nor Wede notably affected the levels of cell apoptosis-associated proteins but these inhibitors regulated the levels of cell pyroptosis-associated proteins. Further, the combination of Beln and Wede exerted greater inhibitory effects on cell pyroptosis than either Beln or Wede alone. Conclusions The results demonstrated that both the canonical and non-canonical signaling pathways of cell pyroptosis are involved in LPS-induced cell damage and that the non-canonical signaling pathway may be involved to a greater extent. This suggests that the inhibition of pyroptosis may exert potential therapeutic effects on SAE.

Possible involvement of PI3K/AKT/mTOR signaling pathway in the protective effect of selegiline (deprenyl) against memory impairment following ischemia reperfusion in rat

Neuropeptides ◽  
2019 ◽  
Vol 77 ◽  
pp. 101942 ◽  
Author(s):  
Hossein Amini-Khoei ◽  
Elham Saghaei ◽  
Gholam-Reza Mobini ◽  
Milad Sabzevary-Ghahfarokhi ◽  
Reza Ahmadi ◽  
...  
Keyword(s):  
Protective Effect ◽  
Signaling Pathway ◽  
Memory Impairment ◽  
Ischemia Reperfusion ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway

DNMT1-mediated lncRNA MEG3 methylation accelerates endothelial-mesenchymal transition in diabetic retinopathy through the PI3K/AKT/mTOR signaling pathway

2020 ◽  
Author(s):  
Yue He ◽  
Yujiao Dan ◽  
Xiaorong Gao ◽  
Li Huang ◽  
Hongbin Lv ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Signaling Pathway ◽  
Dna Methyltransferase ◽  
Cell Model ◽  
Mtor Signaling ◽  
Diabetic Patients ◽  
Cell Models ◽  
Mtor Signaling Pathway ◽  
Mesenchymal Transition ◽  
Endothelial Mesenchymal Transition

Diabetic retinopathy (DR) is one of the serious complications that occur in diabetic patients that frequently causes blindness. Long non-coding RNAs (lncRNAs) have been associated with DR pathology. This study aimed to determine the underlying mechanism of lncRNA maternally expressed gene 3 (MEG3) in association with DNA methyltransferase 1 (DNMT1) in the endothelial-mesenchymal transition (endMT) that occurs in DR. A rat model of DR was induced by streptozotocin (STZ) injection, and high glucose (HG)-induced cell model was established by exposing microvascular endothelial cells obtained from retina of rats to HG. Subsequently, MEG3 was overexpressed in rat and cell models to characterize its impact on endMT in DR and the involvement of the PI3K/AKT/mTOR signaling pathway. Furthermore, the methylation level of MEG3 promoter region was determined with the application of methylation-specific polymerase chain reaction, followed by Chromatin immunoprecipitation assay for methyltransferase enrichment. Finally, we examined the regulation of DNMT1 on MEG3 methylation and endMT in the HG-induced cell model. The results obtained revealed downregulated MEG3 expression in DR rat and cell models. Overexpressed MEG3 was shown to suppress endMT in DR rat and cell models through the inhibition of the PI3K/AKT/mTOR signaling pathway. Notably, DNMT1 could promote MEG3 promoter methylation to inhibit MEG3 expression by recruiting methyltransferase, which activated the PI3K/AKT/mTOR signaling pathway to accelerate endMT in DR. These findings further highlighted the inhibitory effect of MEG3 on endMT in DR, thus presenting a novel therapeutic target candidate for DR treatment.

scholarly journals Apelin-13 Regulates Angiotensin II-Induced Cx43 Downregulation and Autophagy via the AMPK/mTOR Signaling Pathway in HL-1 Cells

2020 ◽  
pp. 813-822
Author(s):  
Y CHEN ◽  
X QIAO ◽  
L ZHANG ◽  
X LI ◽  
Q LIU
Keyword(s):  
Atrial Fibrillation ◽  
Angiotensin Ii ◽  
Signaling Pathway ◽  
Connexin 43 ◽  
Mtor Signaling ◽  
Atrial Remodeling ◽  
Mtor Signaling Pathway ◽  
Cx43 Expression ◽  
Compound C ◽  
Cell Hypertrophy

Atrial fibrillation is associated with atrial remodeling, in which connexin 43 (Cx43) and cell hypertrophy play important roles. In this study, apelin-13, an aliphatic peptide, was used to explore the protective effects of the adenosine monophosphate-activated protein kinase (AMPK)/mTOR signaling pathway on Cx43 expression and autophagy, using murine atrial HL-1 cells. The expression of Cx43, AMPK, B-type natriuretic peptide (BNP) and pathway-related proteins was detected by Western blot analysis. Cellular fluorescence imaging was used to visualize Cx43 distribution and the cytoskeleton. Our results showed that the Cx43 expression was significantly decreased in HL-1 cells treated with angiotensin II but increased in cells additionally treated with apelin-13. Meanwhile, apelin-13 decreased BNP expression and increased AMPK expression. However, the expression of Cx43 and LC3 increased by apelin-13 was inhibited by treatment with compound C, an AMPK inhibitor. In addition, rapamycin, an mTOR inhibitor, promoted the development of autophagy, further inhibited the protective effect on Cx43 expression and increased cell hypertrophy. Thus, apelin-13 enhances Cx43 expression and autophagy via the AMPK/mTOR signaling pathway, and serving as a potential therapeutic target for atrial fibrillation.

Emodin Ameliorate High Glucose-induced Podocyte Apoptosis via Regulating AMPK/mTOR- mediated Autophagy Signaling Pathway

2021 ◽  
Author(s):  
Hong Liu ◽  
Yanglin Hu ◽  
Ge Shi ◽  
Wenqiang Yang ◽  
Fei Xiong ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
High Glucose ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Therapeutic Option ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
Trypan Blue Exclusion ◽  
Compound C

Abstract Background: Podocyte apoptosis and autophagy dysfunction have been considered to be one of the important causes of diabetic nephropathy (DN). Emodin has the function of regulating autophagy. The present study was performed to investigate the effect of emodin on high glucose (HG)-induced podocyte apoptosis and whether the potential anti-apoptotic mechanism of emodin is related to the induction of AMPK/mTOR-mediated autophagy in MPC5 cells in vitro.Methods: The viability and apoptosis of podocytes (MPC5 cells) were detected using CCK-8 assay, trypan blue exclusion assay and flow cytometry analysis, respectively. The expression levels of Cleaved caspase-3, autophagy maker LC3 I/II, and AMPK/mTOR signaling pathway-related proteins were evaluated with western blot analysis. The changes of morphology and RFP-LC3 fluorescence were observed under microscopy.Results: HG (20-160 mmol/L) dose-dependently induced cell apoptosis in MPC5 cells, whereas emodin (4 μmol/L) significantly ameliorated HG-induced cell apoptosis and caspase-3 cleavage. Emodin (4 μmol/L) significantly increased LC3-II levels and induced RFP-LC3-containing punctate structures in MPC5 cells. Furthermore, the protective effects of emodin were mimicked by rapamycin (100 nmol/L). Moreover, emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR. The AMPK inhibitor compound C (10 μmol/L) abolished emodin-induced autophagy activation.Conclusion: Emodin ameliorated HG-induced apoptosis of MPC5 cells in vitro that involved induction of autophagy through the AMPK/mTOR signaling pathway, which might provide a potential therapeutic option for DN.

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