scholarly journals Critical Roles of the PI3K-Akt-mTOR Signaling Pathway in Apoptosis and Autophagy of Astrocytes Induced by Methamphetamine

2019 ◽  
Vol 17 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Han-Qing Liu ◽  
Ya-Wen An ◽  
A-Zhen Hu ◽  
Ming-Hua Li ◽  
Jue-Lian Wu ◽  
...  

AbstractThis study aimed to reveal potential roles of the phosphatidylinositol 3 kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) signaling pathway in apoptosis and autophagy of astrocytes induced by methamphetamine (METH). A Cell Counting Kit-8 (CCK-8) was used to determine the reduction in proliferation of U-118 MG cells induced by METH. Hoechst 33258 and flow cytometry were used to observe the astrocytes. Western blot analysis was performed to evaluate protein expression and phosphorylation levels. METH inhibited the proliferation of U-118 MG cells and induced apoptosis and autophagy. Western blot analysis showed that the ratio of LC3-II/I was increased, whereas the expression of Bcl-2 was decreased. The phosphorylation cascade of kinases in the PI3K-Akt-mTOR signaling pathway was significantly inhibited by METH exposure, as were proteins downstream of mTORC1, such as p70s6k, rps6, 4EBP1 and eIF4E. METH inhibited proliferation of U-118 MG cells and induced apoptosis and autophagy. The PI3K-Akt-mTOR signaling pathway likely plays a critical role in these effects.

2020 ◽  
Author(s):  
Qin Li ◽  
Junyu Shi ◽  
Xiaoli Xu

Abstract Background: MicroRNA-1271-5p (miR-1271-5p) has been reported to participate in the progression of many malignancies. However, the molecular mechanism of miR-1271-5p still remains vague in ovarian cancer (OC). Therefore, we explored the effect of miR-1271-5p in the development of OC in present study.Methods: We measured the miR-1271-5p expression via qRT-PCR assay. Western blot analysis was employed to examine protein expression. Then, the functional mechanism of miR-1271-5p was analyzed by MTT, Transwell and dual luciferase assays.Results: Downregulation of miR-1271-5p was found in OC, which can predict worse prognosis in OC patients. Further, miR-1271-5p directly targets E2F5 in OC. And miR-1271-5p restrained the proliferation, migration and invasion of OC cells via targeting E2F5. Additionally, upregulation of E2F5 was observed in OC, which predicted unfavorable prognosis in OC patients. Besides that, miR-1271-5p suppressed EMT and mTOR pathway in OC.Conclusion: MiR-1271-5p inhibited the tumorigenesis of OC through targeting E2F5 and negatively regulated the mTOR signaling pathway.


2018 ◽  
Vol 16 (1) ◽  
pp. 674-680 ◽  
Author(s):  
Yu Shi ◽  
Feng Wang ◽  
A-Zhen Hu ◽  
Qing-Wen Wang ◽  
Jue-Lian Wu ◽  
...  

AbstractThe aim of this study was to determine the effects of Jinniu Capsule on methamphetamine (METH)-induced conditioned place preference (CPP) in rats and identify the underlying mechanisms. An intraperitoneal injection of 3 mg/kg METH was used for CPP training in rats. The effects of Jinniu Capsule following a single dose on rat CPP and repeat dosing on METH withdrawal were evaluated. Western Blot analysis was used to measure protein expression of the PI3K-AKT-mTOR signaling pathway to determine the mechanisms of Jinniu Capsule. A single dose of Jinniu Capsule did not influence METH-induced CPP in rats. However, repeat dosing for 7 days significantly promoted METH withdrawal. Furthermore, METH withdrawal activated the PI3K-AKT-mTOR signaling pathway phosphorylation cascade, and Jinniu Capsule partly blocked this cascade. Jinniu Capsule demonstrated potential in promoting METH withdrawal in a rat CPP model, which may be related to its influence on the PI3K-AKT-mTOR signaling pathway.


2021 ◽  
Vol 12 ◽  
Author(s):  
Daowei Zhang ◽  
Jiawen Wu ◽  
Jihong Wu ◽  
Shenghai Zhang

Background: Retinal photoreceptor (RP) cells are widely involved in retina-related diseases, and oxidative stress plays a critical role in retinal secondary damage. Herein, we investigated the effectiveness and potential mechanisms of autophagy of paeonol (Pae) in terms of oxidation resistance.Methods: The animal model was induced by light damage (LD) in vivo, whereas the in vitro model was established by H2O2 stimulation. The effectiveness of Pae was evaluated by hematoxylin and eosin, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, immunofluorescence, transmission electron microscopy, electroretinogram, and Western blot analysis in vivo, and the underlying mechanisms of Pae were assessed by Cell Counting Kit-8 assay, reactive oxygen species (ROS) assay, and Western blot analysis in 661W cells. We mainly evaluated the effects of Pae on apoptosis and autophagy.Results: Increased apoptosis of the LD-induced and decreased autophagy of RPs were mitigated by Pae treatment. Pea, which increased the expression of mitochondrial functional protein cytochrome c, reversed the decreased cell viability and autophagy induced by oxidative stress in 661W cells. Experiments showed that autophagy was downregulated in PINK1/Parkin dependent and the BNIP3L/Nix dependent pathways under H2O2 stimulation and was upregulated by Pae treatment. Pae increased the cell viability and reduced ROS levels through autophagy.Conclusion: Pretreatment with Pae preserved RP cells by enhancing autophagy, which protected retinal function.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Han Ki Lee ◽  
Hyo Sun Cha ◽  
Myeong Jin Nam ◽  
Kyungmoon Park ◽  
Yung-Hun Yang ◽  
...  

Broussochalcone A (BCA) is a chalcone compound extracted from the cortex of Broussonetiapapyrifera (L.) Ventenat that exerts various effects, such as potent antioxidant, antiplatelet, and anticancer effects. However, the effects of BCA against cancers have been seldom studied. This study is aimed at demonstrating the apoptotic mechanisms of BCA in A498 and ACHN cells, which are two types of human renal cancer cell lines. MTT, cell counting, and colony formation assays indicated that BCA treatment inhibited cell viability and cell growth. Further, cell cycle analysis revealed that BCA induced cell cycle arrest at the G2/M phase. Annexin V/PI staining and TUNEL assays were performed to determine the apoptotic effects and DNA fragmentation after treatment with BCA. Based on western blot analysis, BCA induced the upregulation of cleaved PARP, FOXO3, Bax, p21, p27, p53, phosphorylated p53 (ser15, ser20, and ser46), and active forms of caspase-3, caspase-7, and caspase-9 proteins, but downregulated the proforms of the proteins. The expression levels of pAkt, Bcl-2, and Bcl-xL were also found to be downregulated. Western blot analysis of nuclear fractionation results revealed that BCA induced the nuclear translocation of FOXO3, which might be induced by DNA damage owing to the accumulation of reactive oxygen species (ROS). Elevated intracellular ROS levels were also found following BCA treatment. Furthermore, DNA damage was detected after BCA treatment using a comet assay. The purpose of this study was to elucidate the apoptotic effects of BCA against renal cancer A498 and ACHN cells. Collectively, our study findings revealed that the apoptotic effects of BCA against human renal cancer cells occur via the elevation of ROS level and activation of the FOXO3 signaling pathway.


2020 ◽  
Vol 27 ◽  
Author(s):  
Naser-Aldin Lashgari ◽  
Nazanin Momeni Roudsari ◽  
Saeideh Momtaz ◽  
Negar Ghanaatian ◽  
Parichehr Kohansal ◽  
...  

: Inflammatory bowel disease (IBD) is a general term for a group of chronic and progressive disorders. Several cellular and biomolecular pathways are implicated in the pathogenesis of IBD, yet the etiology is unclear. Activation of the mammalian target of rapamycin (mTOR) pathway in the intestinal epithelial cells was also shown to induce inflammation. This review focuses on the inhibition of the mTOR signaling pathway and its potential application in treating IBD. We also provide an overview on plant-derived compounds that are beneficial for the IBD management through modulation of the mTOR pathway. Data were extracted from clinical, in vitro and in vivo studies published in English between 1995 and May 2019, which were collected from PubMed, Google Scholar, Scopus and Cochrane library databases. Results of various studies implied that inhibition of the mTOR signaling pathway downregulates the inflammatory processes and cytokines involved in IBD. In this context, a number of natural products might reverse the pathological features of the disease. Furthermore, mTOR provides a novel drug target for IBD. Comprehensive clinical studies are required to confirm the efficacy of mTOR inhibitors in treating IBD.


Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2794 ◽  
Author(s):  
Cao ◽  
Chen ◽  
Ren ◽  
Zhang ◽  
Tan ◽  
...  

Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jie Yao ◽  
Zefen Wang ◽  
Yong Cheng ◽  
Chao Ma ◽  
Yahua Zhong ◽  
...  

Abstract Background Glioma, the most common primary brain tumor, account Preparing figures for 30 to 40% of all intracranial tumors. Herein, we aimed to study the effects of M2 macrophage-derived exosomal microRNAs (miRNAs) on glioma cells. Methods First, we identified seven differentially expressed miRNAs in infiltrating macrophages and detected the expression of these seven miRNAs in M2 macrophages. We then selected hsa-miR-15a-5p (miR-15a) and hsa-miR-92a-3p (miR-92a) for follow-up studies, and confirmed that miR-15a and miR-92a were under-expressed in M2 macrophage exosomes. Subsequently, we demonstrated that M2 macrophage-derived exosomes promoted migration and invasion of glioma cells, while exosomal miR-15a and miR-92a had the opposite effects on glioma cells. Next, we performed the target gene prediction in four databases and conducted target gene validation by qRT-PCR, western blot and dual luciferase reporter gene assays. Results The results revealed that miR-15a and miR-92a were bound to CCND1 and RAP1B, respectively. Western blot assays demonstrated that interference with the expression of CCND1 or RAP1B reduced the phosphorylation level of AKT and mTOR, indicating that both CCND1 and RAP1B can activate the PI3K/AKT/mTOR signaling pathway. Conclusion Collectively, these findings indicate that M2 macrophage-derived exosomal miR-15a and miR-92a inhibit cell migration and invasion of glioma cells through PI3K/AKT/mTOR signaling pathway.


2021 ◽  
Vol 22 (5) ◽  
pp. 2274
Author(s):  
Hyun-Su Lee ◽  
Eun-Nam Kim ◽  
Gil-Saeng Jeong

Methamphetamine (METH) is a highly addictive drug that induces irreversible damage to neuronal cells and pathological malfunction in the brain. Aromadendrin, isolated from the flowers of Chionanthus retusus, has been shown to have anti-inflammatory or anti-tumor activity. Nevertheless, it has been reported that METH exacerbates neurotoxicity by inducing endoplasmic reticulum (ER) stress via the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway in neuronal cells. There is little evidence that aromadendrin protects cells from neurotoxicity induced by METH. In this study, we found that aromadendrin partially suppressed the METH-induced cell death in SH-SY5y cells without causing cytotoxicity. Aromadendrin regulated METH-induced ER stress by preserving the phosphorylation of the PI3K/Akt/mTOR signaling pathway in METH-exposed SH-SY5y cells. In addition, aromadendrin mitigated METH-induced autophagic and the apoptotic pathways in METH-exposed SH-SY5y cells. Mechanistic studies revealed that pre-treatment with aromadendrin restored the expression of anti-apoptotic proteins in METH-exposed conditions. The inhibitor assay confirmed that aromadendrin-mediated restoration of mTOR phosphorylation protected cells from autophagy and apoptosis in METH-exposed cells. Therefore, these findings suggest that aromadendrin relatively has a protective effect on SH-SY5y cells against autophagy and apoptosis induced by METH via regulation of ER stress and the PI3K/Akt/mTOR signaling pathway.


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