Knockdown of PDCD4 ameliorates neural cell apoptosis and mitochondrial injury through activating the PI3K/AKT/mTOR signal in Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a complex neurodegenerative disorder and hampers normal living. It has been reported that programmed cell death 4 (PDCD4) is associated with tumor suppression, inflammatory response, and apoptosis.

OBJECTIVE

The aim of this study was to investigate the role of PDCD4 in PD.

METHODS

The in vivo and in vitro PD models were established by MPTP-induced mice and MMP+ stimulated MN9D cells, respectively. The expression of PDCD4 was detected by western blot. The MN9D cell viability and apoptosis were determined by MTT and flow cytometry assay. Moreover, the MN9D cell mitochondrial injury was evaluated by JC-1 staining.

RESULTS

In this study, PDCD4 was highly expressed in brain tissue of MPTP-induced PD mouse model. In a loss-function experiments, knockdown of PDCD4 promoted MN9D cell viability and allayed MPP+-triggered MN9D cell apoptosis. Furthermore, knockdown of PDCD4 ameliorated MPP+-evoked MN9D cell mitochondrial injury. Mechanically, knockdown of PDCD4 abolished the effect of MMP+ stimulation via activating phosphoinositide 3-kinase(PI3K)/AKT/mammalian target of rapamycin (mTOR) signal. Notably, the protective effects of shPDCD4 on cell apoptosis and mitochondrial injury were suppressed by PI3K inhibitor LY294002.

CONCLUSION

In summary,knockdown of PDCD4 ameliorates neural cell apoptosis and mitochondrial injury through activating the PI3K/AKT/mTOR signal, providing a novel target for PD treatment.

AVAILABILITY OF DATA AND MATERIALS

All data generated or analyzed during this study are included in this published article.

Trimethylamine N-oxide Promotes Atherosclerosis by Regulating Low-Density Lipoprotein-Induced Autophagy in Vascular Smooth Muscle Cells Through PI3K/AKT/mTOR Pathway

The research aimed to study the mechanism of how trimethylamine N-oxide (TMAO) regulates autophagy to promote atherosclerosis (AS). The AS in vitro model was constructed with vascular smooth muscle cells (VSMCs) treated with ox-LDL. The Cell Counting Kit-8 (CCK-8) trial was chosen to examine VSMCs' absorbance (OD) value. A transmission electron microscope (TEM) was selected for monitoring autophagosomes. Western blotting (WB) was adopted for examining the expression of Beclin-1, p62, LC3, α-SMA, SM22-α, OPN, PI3K, AKT, mTOR, p-PI3K, p-AKT, and p-mTOR proteins. Real-time fluorescent quantitative PCR (RT-qPCR) was accepted for testing the expression of α-SMA, SM22-α, OPN, PI3K, AKT, mTOR, Beclin-1, p62, and LC3 genes. The transwell assay was employed to examine the ability of migration in VSMCs. Oil red O staining assay was accepted to stain lipid droplets in VSMCs. TMAO noticeably promoted autophagy inhibition and the phenotypic transformation of AS. Protein expressions of p-PI3K/PI3K, p-AKT/AKT, p-mTOR/mTOR, and p62 of the TMAO+ox-LDL group were higher than the ox-LDL group, while Beclin-1 and LC3 were lower than the ox-LDL group. Gene expressions of PI3K, AKT, mTOR, and p62 of the TMAO+ox-LDL group were higher than the ox-LDL group, while Beclin-1 and LC3 were lower than the ox-LDL group. The intervention of LY294002 reversed the regulation of the corresponding proteins and genes. The study proved that TMAO could promote autophagy inhibition of AS via activating the PI3K/AKT/mTOR pathway. It supplied a reliable basis for improving clinical diagnostic methods and developing targeted AS drugs.

Galangin attenuates oxidative stress-mediated apoptosis in high glucose-induced renal tubular epithelial cells through modulating renin-angiotensin system and PI3K/AKT/mTOR pathway

This study was to evaluate the regulatory network among Galangin (Gal), oxidative stress, and renin-angiotensin system (RAS) in diabetic nephropathy (DN) in vitro. A cell model of DN was set up by exposing HK-2 cells to high glucose (HG, 30 mM) for 48 h and Gal was applied at 10 μM when needed. mRNA expression was analyzed by qPCR and protein level was detected by western blot. Malondialdehyde level and superoxide dismutase activity were evaluated by commercial kits. We analyzed cell viability by CCK8 assay and apoptosis by flow cytometry. DCFH-DA staining was conveyed for reactive oxygen species detection. HG induced RAS activation, oxidative stress, while inhibited cell viability. Gal suppressed oxidative stress-mediated apoptosis of HK-2 cells under the stimulation of HG via inhibiting RAS activation. Moreover, overexpression of AT1R, a RAS gene, could restrain the mitigative effect of Gal on cell injury. Furthermore, repression of RAS induced by AT1R knockdown partially reversed HG-induced PI3K/AKT/mTOR activation and oxidative stress in HK-2 cells. Also, AKT activation could antagonize Gal's functional roles in renal cell damage. Collectively, Gal alleviates HG-induced oxidative stress injury of renal tubular epithelial cells through PI3K/AKT/mTOR signal via modulating RAS activation. This finding would help to better understand mechanism of DN development and support future studies.

Long noncoding RNA HAGLROS promotes the process of mantle cell lymphoma by regulating miR-100/ATG5 axis and involving in PI3K/AKT/mTOR signal

This research planned to grab the expression and impact of lncRNA HAGLROS in the biology and progression of mantle cell lymphoma. HAGLROS level in mantle cell lymphoma cell lines was detected, followed by investigation of the influences of HAGLROS silencing on Mino cell biological performances. Afterwards, the express patterns of HAGLROS vs. miR-100, as well as miR-100 vs. ATG5, were investigated. Furthermore, whether HAGLROS could regulate the signals of PI3K/AKT/mTOR was analyzed. HAGLROS level was high in mantle cell lymphoma cell lines. Silencing of HAGLROS inhibited Mino cell viability, increased apoptosis and decreased autophagy by sponging miR-100. Moreover, miR-100 targeted ATG5 fixed. Furthermore, HAGLROS suppression resulted in inhibition on the briskness of PI3K/AKT/mTOR signals. Concurrently HAGLROS suppression and miR-100 inhibitor markedly changed the impacts of HAGLROS down-regulation alone on activating PI3K/AKT/mTOR signals, which could further change after co-transfection of si-HAGLROS + miR-100 inhibitor + siATG5. Our findings point out that expression of HAGLROS is increased in mantle cell lymphoma cells and may function as an oncogene in mantle cell lymphoma. HAGLROS may promote tumour development by regulating miR-100/ATG5/PI3K/AKT/mTOR axis.