scholarly journals 17β-Estradiol Induces Mitophagy Upregulation to Protect Chondrocytes via the SIRT1-Mediated AMPK/mTOR Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Runhong Mei ◽  
Peng Lou ◽  
Guanchao You ◽  
Tianlong Jiang ◽  
Xuefeng Yu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Western Blotting ◽  
Mtor Signaling ◽  
Sirtuin 1 ◽  
Mtor Signaling Pathway ◽  
Compound C ◽  
Transmission Electron ◽  
Sirt1 Inhibitor ◽  
17Β Estradiol ◽  
Related Proteins

Increasing evidence reveals that estrogen, especially 17β-estradiol (17β-E2), is associated with articular cartilage metabolism disorder and postmenopausal osteoarthritis (OA). SIRT1, AMPK, and mTOR are regarded as critical mitophagy regulators. Recent studies have shown that mitophagy displays a protective effect against OA, but the molecular mechanism is not well known. This study aimed to investigate the effect of 17β-E2 on Sirtuin-1 (SIRT1) expression and the induction of mitophagy upregulation by 17β-E2 via the SIRT1-mediated AMP-activated protein kinase (AMPK)/mammalian target of the rapamycin (mTOR) signaling pathway to protect chondrocytes. ATDC5 chondrocytes were treated with different concentrations of 17β-E2 (0 M, 1 × 10-9 M, 1 × 10-8 M, and 1 × 10-7 M) for 24 h or pretreatment with or without NAM (SIRT1 inhibitor), Compound C (AMPK inhibitor) and S1842 (mTOR inhibitor) for 30 min prior to treatment with 17β-E2 (1 × 10-7 M) for 24 in each groups. Expression of SIRT1 was evaluated by real-time PCR, Western blotting and confocal immunofluorescence staining. Then, the mitophagosomes in cells were observed under a transmission electron microscopy (TEM), and the AMPK/mTOR signaling pathway was detected by Western blotting. The mitophagy-related proteins, p-AMPK, p-mTOR, p-JNK, and p-p38 were also identified by Western blot analysis. The chondrocytes viability and proliferation were determined by MTT and 5-Bromo-2’-deoxyuridine (BrdU) assay. These experiments were independently repeated 3 times The study found that 17β-E2 increased the expression level of SIRT1, p-AMPK, and mitophagy-related proteins but decreased p-mTOR expression, and then induced mitophagy upregulation in chondrocytes. More mitochondrial autophagosomes were observed in 17β-E2-treated chondrocytes under a transmission electron microscope. Also, 17β-E2 improved cell viability and proliferation with the higher expression of SIRT1 and activation of the AMPK/mTOR signaling pathway. However, SIRT1 inhibitor nicotinamide (NAM) and AMPK inhibitor Compound C blocked the beneficial effect of 17β-E2. In summary, this study was novel in demonstrating that 17β-E2 induced mitophagy upregulation to protect chondrocytes via the SIRT1-mediated AMPK/mTOR signaling pathway.

scholarly journals Andrographolide enhanced radiosensitivity by downregulating glycolysis via the inhibition of the PI3K-Akt-mTOR signaling pathway in HCT116 colorectal cancer cells

2020 ◽  
Vol 48 (8) ◽  
pp. 030006052094616 ◽  
Author(s):  
Xiaofei Li ◽  
Ruifang Tian ◽  
Lan Liu ◽  
Lihui Wang ◽  
Dong He ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Survival ◽  
Signaling Pathway ◽  
Colony Formation ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
Glycolytic Activity ◽  
Related Proteins ◽  
Hct116 Cells

Objective Radiotherapy plays an important role in the treatment of colorectal cancer (CRC). However, some patients benefit minimally from radiotherapy because of radioresistance. This study investigated the effects of andrographolide on radiosensitivity in HCT116 CRC cells and examined its mechanism of action. Methods Cell survival, proliferation, apoptosis, and migration were evaluated using MTT, colony formation, flow cytometry, and Transwell cell invasion assays, respectively. Glycolysis-related indicators were measured to examine cell glycolytic activity. The expression of related proteins was detected by western blotting. Results After andrographolide treatment, the expression of phosphoinositide 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway-related proteins, glycolytic activity, and cell survival and invasion rates were decreased in HCT116 cells. Andrographolide plus irradiation increased apoptosis and decreased survival, invasion, and colony formation compared with the effects of irradiation alone. Conclusion Andrographolide enhanced radiosensitivity by downregulating glycolysis via inhibition of the PI3K-Akt-mTOR signaling pathway in HCT116 cells.

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 GPR30 Activation by 17β-Estradiol Promotes p62 Phosphorylation and Increases Estrogen Receptor α Protein Expression by Inducing Its Release from a Complex Formed with KEAP1

2021 ◽  
Vol 11 (9) ◽  
pp. 906
Author(s):  
Chia-Lung Tsai ◽  
Chiao-Yun Lin ◽  
Angel Chao ◽  
Yun-Shien Lee ◽  
Ren-Chin Wu ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Protein Expression ◽  
Signaling Pathway ◽  
Critical Role ◽  
Adaptor Protein ◽  
Estrogen Receptor Α ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
17Β Estradiol ◽  
Esr1 Expression

Estrogens can elicit rapid cellular responses via the G-protein-coupled receptor 30 (GPR30), followed by estrogen receptor α (ERα/ESR1)-mediated genomic effects. Here, we investigated whether rapid estrogen signaling via GRP30 may affect ESR1 expression, and we examined the underlying molecular mechanisms. The exposure of human endometrial cancer cells to 17β-estradiol promoted p62 phosphorylation and increased ESR1 protein expression. However, both a GPR30 antagonist and GPR30 silencing abrogated this phenomenon. GPR30 activation by 17β-estradiol elicited the SRC/EGFR/PI3K/Akt/mTOR signaling pathway. Intriguingly, unphosphorylated p62 and ESR1 were found to form an intracellular complex with the substrate adaptor protein KEAP1. Upon phosphorylation, p62 promoted ESR1 release from the complex, to increase its protein expression. Given the critical role played by p62 in autophagy, we also examined how this process affected ESR1 expression. The activation of autophagy by everolimus decreased ESR1 by promoting p62 degradation, whereas autophagy inhibition with chloroquine increased ESR1 expression. The treatment of female C57BL/6 mice with the autophagy inhibitor hydroxychloroquine—which promotes p62 expression—increased both phosphorylated p62 and ESR1 expression in uterine epithelial cells. Collectively, our results indicate that 17β-estradiol-mediated GPR30 activation elicits the SRC/EGFR/PI3K/Akt/mTOR signaling pathway and promotes p62 phosphorylation. In turn, phosphorylated p62 increased ESR1 expression by inducing its release from complexes that included KEAP1. Our findings may lead to novel pharmacological strategies aimed at decreasing ESR1 expression in estrogen-sensitive cells.

scholarly journals Changes of Three kinds of miRNAs, MALAT1 and PI3K/AKT/mTOR signaling pathway Protein Levels in Her-2 Positive Breast Cancer in neoadjuvant chemotherapy and their relationship with prognosis- -A small sample study report

2020 ◽  
Author(s):  
Zhao Hongcan ◽  
zhang xiping
Keyword(s):  
Neoadjuvant Chemotherapy ◽  
Signaling Pathway ◽  
Chemotherapy Resistance ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
Serum Samples ◽  
Before And After ◽  
Her 2 ◽  
Related Proteins ◽  
Positive Breast Cancer

Abstract Objective To investigate the roles of three kinds of miRNAs (MiR-99a, MiR-455 and MiR-143), Lnc MALAT1 and related proteins of PI3K/AKT/mTOR signaling pathway in neoadjuvant chemotherapy of patients with Her-2 positive breast cancer (BC) and analysed their related mechanisms. Method The frozen tumor tissue and serum samples before and after neoadjuvant chemotherapy of 14 cases patients with Her-2 positive BC who received neoadjuvant chemotherapy were collected. The relative expressions level of MiR-99a, MiR-455, MiR-143, MALAT1 and related proteins of PI3K/AKT/mTOR signaling pathway in tumor tissue and a part of serum samples were detected by qRT-PCR or western blot. Results MiR-99a level was negatively correlated with RFS and OS before and after chemotherapy. MiR-99a and MiR-455 levels after chemotherapy was negatively correlated with OS. The serum MALAT1 level was negatively correlated with RFS and OS in chemosensitivity group before and after chemotherapy. In chemotherapy resistance group, p-AKT level before chemotherapy was negatively correlated with T stage, p-mTOR level after chemotherapy was positively correlated with lymph node stage and negatively correlated with RFS and OS, PTEN level was negatively correlated with clinical TNM stage. Conclusion Serum MALAT1 and MiR-99a, MiR-455, MiR-143, p-AKT, p-mTOR and PTEN of tumor tissues in Her-2 positive BC patients can be used as markers to judge neoadjuvant chemotherapy sensitivity in Her-2 positive BC. Chemotherapy resistance is may be related to PI3K/AKT/mTOR signaling pathway.

scholarly journals 8-Gingerol Ameliorates Myocardial Fibrosis by Attenuating Reactive Oxygen Species, Apoptosis, and Autophagy via the PI3K/Akt/mTOR Signaling Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Yucong Xue ◽  
Muqing Zhang ◽  
Miaomiao Liu ◽  
Yu Liu ◽  
Li Li ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Signaling Pathway ◽  
Myocardial Fibrosis ◽  
Marked Decrease ◽  
Mtor Signaling ◽  
Ros Generation ◽  
Oxygen Species ◽  
Mtor Signaling Pathway ◽  
Weight Index ◽  
Related Proteins

8-gingerol (8-Gin) is the series of phenolic substance that is extracted from ginger. Although many studies have revealed that 8-Gin has multiple pharmacological properties, the possible underlying mechanisms of 8-Gin against myocardial fibrosis (MF) remains unclear. The study examined the exact role and potential mechanisms of 8-Gin against isoproterenol (ISO)-induced MF. Male mice were intraperitoneally injected with 8-Gin (10 and 20 mg/kg/d) and concurrently subcutaneously injected with ISO (10 mg/kg/d) for 2 weeks. Electrocardiography, pathological heart morphology, myocardial enzymes, reactive oxygen species (ROS) generation, degree of apoptosis, and autophagy pathway-related proteins were measured. Our study observed 8-Gin significantly reduced J-point elevation and heart rate. Besides, 8-Gin caused a marked decrease in cardiac weight index and left ventricle weight index, serum levels of creatine kinase and lactate dehydrogenase (CK and LDH, respectively), ROS generation, and attenuated ISO-induced pathological heart damage. Moreover, treatment with 8-Gin resulted in a marked decrease in the levels of collagen types I and III and TGF-β in the heart tissue. Our results showed 8-Gin exposure significantly suppressed ISO-induced autophagosome formation. 8-Gin also could lead to down-regulation of the activities of matrix metalloproteinases-9 (MMP-9), Caspase-9, and Bax protein, up-regulation of the activity of Bcl-2 protein, and alleviation of cardiomyocyte apoptosis. Furthermore, 8-Gin produced an obvious increase in the expressions of the PI3K/Akt/mTOR signaling pathway-related proteins. Our data showed that 8-Gin exerted cardioprotective effects on ISO-induced MF, which possibly occurred in connection with inhibition of ROS generation, apoptosis, and autophagy via modulation of the PI3K/Akt/mTOR signaling pathway.

Vitexin Inhibits the Proliferation and Promotes the Apoptosis of Gastric Cancer Cells via Phosphatidylinositol-3-Kinase (PI3K)/Protein Kinase B (Akt)/The Mammalian Target of Rapamycin (mTOR) Signaling Pathway

2020 ◽  
Vol 10 (12) ◽  
pp. 1843-1850
Author(s):  
M. M. Jiashu Lu ◽  
M. M. Lei Yu ◽  
M. M. Ying Ma ◽  
M. M. Jie Li
Keyword(s):  
Gastric Cancer ◽  
Survival Rate ◽  
Signaling Pathway ◽  
Mtor Signaling ◽  
Flavonoid Compound ◽  
High Morbidity ◽  
Mtor Signaling Pathway ◽  
Gastric Cancer Cells ◽  
Apoptosis Rate ◽  
Related Proteins

Gastric cancer (GC) is a kind of digestive tract malignancy that has very high morbidity and mortality, making it crucial to find new drug treatments. Vitexin is a kind of flavonoid compound, which has anti-tumor, anti-inflammatory, analgesic and antiviral effects, etc. However, the specific role of vitexin in GC is still unclear. In this study, the expression of the survival rate and apoptosis was detected by CCK-8 and flow cytometry after vitexin acted on cells. Plasmid transfection technique was used to overexpress PI3K. Expression of PI3K/AKT/mTOR pathway-related proteins, autophagic-related proteins (Atg14, beclin-1, P62) and apoptotic-related proteins (bcl-2, Bax, cleaved caspase3) were detected by Western blot. We found that the cell survival rate decreased with the increasing time and dosage of vitexin. When vitexin acted on cells, the expression of p-PI3K, p-AKT and p-mTOR was significantly decreased, the degree of autophagy was increased, and the apoptosis rate was obviously increased. However, the overexpression of PI3K, the level of autophagy and apoptosis rate of cells which were given vitexin significantly decreased. In conclusion, Vitexin induces autophagy by inhibiting PI3K/AKT/mTOR signaling pathway, thereby inhibiting proliferation and promoting apoptosis of GC cells.

scholarly journals SETDB1 Promotes the Growth of Glioma via CSF-1-dependent Macrophage Recruitment by Activating the AKT/mTOR Signaling Pathway

2020 ◽  
Author(s):  
Shuai Han ◽  
Wei Zhen ◽  
Tongqi Guo ◽  
Jianjun Zou ◽  
fuyong li
Keyword(s):  
Real Time ◽  
Signaling Pathway ◽  
Western Blotting ◽  
Real Time Pcr ◽  
Mtor Signaling ◽  
Migration And Invasion ◽  
High Morbidity ◽  
Mtor Signaling Pathway ◽  
Macrophage Recruitment ◽  
Syngeneic Mouse Model

Abstract Background: Glioma is a common disease of the central nervous system (CNS), with high morbidity and mortality. Among the infiltrates in the tumor microenvironment, tumor-associated macrophages (TAMs) are abundant and they are significant factors in glioma progression. However, the exact details of disease progression have yet to be determined. Methods: The clinical relevance of SETDB1 was analyzed by immunohistochemistry, real-time PCR and Western blotting and of glioma cancer tissues. Tumor cell proliferation, migration and invasion were investigated by MTS assay, colony formation assay, xenograft, wound healing and Transwell assay. The relationship between SETDB1 and CSF-1, as well as TAMS was examined by Western blotting, real-time PCR and syngeneic mouse model.Results: This work shows the presence and upregulation of SETDB1 in gliomaand its relationship with disease prognosis. Gain and loss of function approaches showed the inhibition of apoptosis and the promotion of growth, migration and invasion of the disease with SETDB1 overexpression and converse effects with SETDB1 silencing in vitro. Mechanistically, SETDB1 promotes CSF-1 expression by activating the AKT/mTOR signaling pathway. This leads to macrophage recruitment in the tumor, leading to tumor growth. Conclusion: This studyclarifies the modulation of tumor functions by SETDB1 and hence presents a future avenue for treating glioma.

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.

Sign in / Sign up

Export Citation Format

Share Document