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DEAD-Box Helicase 5(DDX5), also known as P68, is one of the founding members of the DEAD-Box helicase superfamily and it plays a key role in RNA metabolism. Several studies have reported that DDX5 is involved in many types of tumors through abnormal expression, but the detailed mechanism of DDX5 in esophageal squamous cell carcinoma (ESCC) has not been elucidated. In this study, we demonstrate that the level of DDX5 is a negative prognostic factor for ESCC. The obtained results indicated that decreased expression of DDX5 inhibits ESCC cell proliferation and metastasis. Further experiments suggested that CDK2, Cyclin D1 and Vimentin were downregulated, while E-cadherin was upregulated after DDX5 was knocked down. In addition, DDX5 was positively correlated with the expression of BIP, phospho-eIF2α, phospho-PERK and P62, suggesting that knockdown of DDX5 can inhibit endoplasmic reticulum(ER) stress and promote the recovery of autophagy flux. Therefore, this study demonstrates that the downregulation of DDX5 in ESSC correlates to lower malignancy and presents a novel target for the development of new treatment strategies., Competing Interests: Declaration of competing interest No conflicts to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective To investigate the effects of quercetin on cell viability,apoptosis,autophagy,and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)signaling pathway in human prostate cell carcinoma PC-3 cells.Methods PC-3 cells were cultured in vitro ,and cell viability was detected by CCK-8.Apoptosis was detected by TUNEL staining.Autophagy vesicle was observed by acridine orange staining.Autophagosomes was observed by GFP-LC3 plasmid transfection analysis.Expressions of autophagy-related protein microtubule associated protein 1 light chain 3 fusion protein(LC3)and Beclin-1 and PI3K/Akt/mTOR signaling pathway protein were detected by Western blot analysis.Results Quercetin inhibited cell viability in a dose-time dependent manner and induced apoptosis.Quercetin increased the number of autophagy vesicles and autophagosomes in PC-3 cells.Quercetin increased the expressions of LC3-Ⅱ/LC3-Ⅰ and Beclin-1 in PC-3 cells and decreased the expression of phosphorylated-PI3K,phosphorylated-Akt and phosphorylated-mTOR.Conclusion Quercetin may induce autophagy by inactivating PI3K/Akt/mTOR signaling pathway in PC-3 cells.

The human immunodeficiency virus-1 (HIV-1) regulatory protein Tat plays an important role during HIV-1-associated neurocognitive disorders (HAND) by inducing neuronal autophagy. In this study, we used immunohistochemistry, immunofluorescence, western blot, qRT-PCR, and RNA interference to elucidate the involvement of Bcl-2-associated athanogene 3 (BAG3) in the pathogenesis of HIV-1 Tat-induced autophagy during HAND. We found that BAG3 expression is elevated in astrocytes in frontal cortex of macaques infected with simian immunodeficiency virus-human immunodeficiency chimeric virus (SHIV). In addition, in human primary glioblastoma cells (U87), HIV-1 Tat upregulated BAG3 in an NF-κB-dependent manner to induce autophagy. Importantly, suppression of BAG3 or inhibition of NF-κB activity reversed the HIV-1 Tat-induced autophagy. These results indicate that HIV-1 Tat induces autophagy by upregulating BAG3 via NF-κB signaling, which suggests BAG3 and NF-κB could potentially serve as novel targets for HAND therapies.

Eukaryotic cells have evolved robust mechanisms to counter excess cholesterol including redistribution of lipids into different compartments and compensatory up-regulation of phospholipid biosynthesis. We demonstrate here that excess cellular cholesterol increased the activity of the endoplasmic reticulum (ER) enzyme serine palmitoyl-CoA transferase (SPT), the rate-limiting enzyme in sphingomyelin synthesis. This increased SPT activity was not due to altered levels of SPTLC1 or SPTLC2, the major subunits of SPT. Instead, cholesterol loading decreased the levels of ORMDL1, a negative regulator of SPT activity, due to its increased turnover. Several lines of evidence demonstrated that free-cholesterol-induced autophagy, which led to increased turnover of ORMDL1. Cholesterol loading induced ORMDL1 redistribution from the ER to cytoplasmic p62 positive autophagosomes. Coimmunoprecipitation analysis of cholesterol-loaded cells showed increased association between ORMDL1 and p62. The lysosomal inhibitor chloroquine or siRNA knockdown of Atg7 inhibited ORMDL1 degradation by cholesterol, whereas proteasome inhibitors showed no effect. ORMDL1 degradation was specific to free-cholesterol loading as autophagy induced by serum starvation or general ER stress did not lead to ORMDL1 degradation. ORMDL proteins are thus previously unidentified responders to excess cholesterol, exiting the ER to activate SPT and increase sphingomyelin biosynthesis, which may buffer excess cellular cholesterol.

Cholesterol confers unique biophysical properties to the plasma membrane bilayer that are essential for maintaining optimal membrane fluidity, which in turn regulate multiple physiological functions required to promote cellular integrity and viability. Conversely, excessive cholesterol causes pathological conditions such as atherosclerosis that can lead to heart attacks. Human atheroma macrophages carry a large burden of free cholesterol (FC) in addition to cholesterol esters. It is recognized that sterols can modulate the levels of other lipids to attain lipid homeostasis; thus, excess FC may play a role in modulating compensatory sphingolipid pathways. Recent studies have shown that excess lipids can cause ER stress and apoptosis. In contrast, autophagy may play a protective role by clearing excess lipids from macrophage foam cell lipid droplets. Interestingly, a macrophage study using a TLR4-specifc agonist showed that de novo sphingolipid biosynthesis is essential for autophagy induction, suggesting links between sphingolipid biosynthesis and autophagy. While the role of autophagy in removing excess lipids has been the focus of many studies, its role in fine-tuning cellular lipid homeostasis remains largely unexplored.

Gouty arthritis (GA) is an inflammatory disease owing to the accumulation of monosodium urate (MSU) in joints, leading to redness and burning pain. In this study, the effect of Zisheng Shenqi Decoction (ZSD) on a rat model of MSU-induced GA was investigated. ZSD obviously diminished the right paw thickness, the degree of the swelling of the paw, and the infiltration of the inflammatory cell, as well as cartilage erosion, and widened the joint space in MSU-treated rats. Besides, MSU remarkably elevated the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-18; however, ZSD treatment dose dependently lowered these levels and resulted in a significant decrease in articular elastase activity. Also, ZSD administration increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) but declined malondialdehyde (MDA) and nitrogen monoxide (NO) contents. Importantly, western blotting analysis revealed that NOD-like receptor protein 3 (NLRP3), cleaved caspase-1, IL-1β, nuclear factor-E2-related factor 2 (Nrf2) in the cytoplasm, phosphorylated mammalian target of rapamyclin (p-mTOR), and p62 expressions were downregulated, whereas the levels of nuclear Nrf2, phosphorylated AMP-activated protein kinase (p-AMPK), Beclin-1, and LC3II/I were upregulated by ZSD. Immunofluorescence assay indicated that ZSD evidently promoted nuclear translocation of LC3. Taken together, ZSD inhibited inflammation and oxidative stress and facilitated autophagy through the activation of the AMPK pathway and suppression of the mTOR signaling pathway, demonstrating its potential for preventing and curing GA. [ABSTRACT FROM AUTHOR]