Induction of PDCD4 by albumin in proximal tubule epithelial cells potentiates proteinuria-induced dysfunctional autophagy by negatively targeting Atg5.

Autophagy dysfunction is a hallmark of type 1 diabetes. However, the precise molecular mechanism of proteinuria-induced dysfunctional autophagy remains unclear. Herein, we investigated the role of programmed cell death 4 (PDCD4) in the regulation of autophagy in the pathogenesis of diabetic kidney disease (DKD) in vivo and in vitro. RT-qPCR, immunohistochemistry (IHC), and western blotting demonstrated an upregulation of Pdcd4 mRNA and protein in streptozotocin (STZ)-induced DKD rats, as compared to the control. In addition, IHC and western blotting of a unilateral ureteral obstruction mouse model showed an upregulation of PDCD4 in the disease group, as compared to their respective controls. IHC analysis of kidney biopsy samples of human DKD patients showed an upregulation of PDCD4 compared to the control. Western blotting of the STZ-induced DKD rat tissues displayed a low microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, as compared to the control. It was found that albumin overload in cultured PTECs upregulated the expression of PDCD4 and p62 and decreased the expression of LC3-II and autophagy-related 5 (Atg5) proteins. The knockout of Pdcd4 in cultured PTECs could reduce albumin-induced dysfunctional autophagy, as evidenced by the recovery of Atg5 and LC3-II protein. The forced expression of PDCD4 could further suppress the expression of the crucial autophagy-related gene Atg5. Evidence suggests that endogenous PDCD4 promotes proteinuria-induced dysfunctional autophagy by negatively regulating Atg5. Therefore, PDCD4 may be a potential therapeutic target in DKD.

Inhibition of miR-188-5p alleviates hepatic fibrosis by significantly reducing the activation and proliferation of HSCs through PTEN/PI3K/AKT pathway.

Persistent hepatic damage and chronic inflammation in liver activate the quiescent hepatic stellate cells (HSCs) and cause hepatic fibrosis (HF). Several microRNAs regulate the activation and proliferation of HSCs, thereby playing a critical role in HF progression. Previous studies have reported that miR-188-5p is dysregulated during the process of HF. However, the role of miR-188-5p in HF remains unclear. This study investigated the potential role of miR-188-5p in HSCs and HF. Firstly, we validated the miR-188-5p expression in primary cells isolated from liver of carbon tetrachloride (CCl4 )-induced mice, TGF-ß1-induced LX-2 cells, livers from 6-month high-fat diet (HFD)-induced rat and 4-month HFD-induced mice NASH models, and human non-alcoholic fatty liver disease (NAFLD) patients. Furthermore, we used miR-188-5p inhibitors to investigate the therapeutic effects of miR-188-5p inhibition in the HFD + CCl4 induced in vivo model and the potential role of miR-188-5p in the activation and proliferation of HSCs. This present study reported that miR-188-5p expression is significantly increased in the human NAFLD, HSCs isolated from liver of CCl4 induced mice, and in vitro and in vivo models of HF. Mimicking the miR-188-5p resulted in the up-regulation of HSC activation and proliferation by directly targeting the phosphatase and tensin homolog (PTEN). Moreover, inhibition of miR-188-5p reduced the activation and proliferation markers of HSCs through PTEN/AKT pathway. Additionally, in vivo inhibition of miR-188-5p suppressed the HF parameters, pro-fibrotic and pro-inflammatory genes, and fibrosis. Collectively, our results uncover the pro-fibrotic role of miR-188-5p. Furthermore, we demonstrated that miR-188-5p inhibition decreases the severity of HF by reducing the activation and proliferation of HSCs through PTEN/AKT pathway.

The Human Novel Gene LNC-HC Inhibits Hepatocellular Carcinoma Cell Proliferation by Sequestering hsa-miR-183-5p.

Hepatocellular carcinoma (HCC) is the most commonly diagnosed cancer and the leading cause of cancer mortality. Several lines of evidence have demonstrated the aberrant expression of long noncoding RNAs (lncRNAs) in carcinogenesis and their universal regulatory properties. A thorough understanding of lncRNA regulatory roles in HCC pathology would contribute to HCC prevention and treatment. In this study, we identified a novel human lncRNA, LNC-HC, with significantly reduced levels in hepatic tumors from patients with HCC. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-dimethyltetrazolium bromide) assays as well as colony formation and wound healing experiments showed that LNC-HC significantly inhibited the proliferation of the HCC cell line Huh7. Xenograft transplantation of LNC-HC-overexpressing Huh7 cells in nude mice resulted in the production of smaller tumors. Mechanistically, LNC-HC inhibited the proliferation of HCC cells by directly interacting with hsa-miR-183-5p. LNC-HC rescued the expression of five tumor suppressors, including AKAP12, DYRK2, FOXN3, FOXO1, and LATS2, that were verified as target genes of hsa-miR-183-5p. Overall, human LNC-HC was identified as a novel tumor suppressor that could inhibit HCC cell proliferation in vitro and suppress tumor growth in vivo by competitively binding hsa-miR-183-5p as a competing endogenous RNA (ceRNA). These findings suggest that LNC-HC could be a biomarker of HCC and provide a novel therapeutic target for HCC treatment.