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.

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.

C-reactive protein exacerbates epithelial-mesenchymal transition through Wnt/ß-catenin and ERK signaling in streptozocin-induced diabetic nephropathy.

Previous studies have reported the pathogenic role of C-reactive protein (CRP) during diabetic kidney disease (DKD) in human CRP transgenic and Crp-/- mice. However, because humans and mice have inverse acute phase expression patterns of CRP and serum amyloid P component, this could lead to the inaccurate evaluation of CRP function with the above-mentioned CRP transgenic mouse. But different from mice, rats have the same acute phase protein expression pattern as human, which might avoid this problem and be a better choice for CRP function studies. To dispel this doubt and accurately define the role of CRP during diabetic nephropathy, we created the first Crp-/- rat model, which we treated with streptozocin to induce DKD for in vivo studies. Moreover, an established cell line (human kidney 2) was used to further investigate the pathologic mechanisms of CRP. We found that CRP promotes epithelial-mesenchymal transition (EMT) through Wnt/ß-catenin and ERK1/2 signaling, which are dependent on CRP binding to FcγRII on apoptotic cells. By promoting EMT, CRP was demonstrated to accelerate the development of DKD. We thus present convincing evidence demonstrating CRP as a therapeutic target for DKD treatment.-Zhang, L., Shen, Z.-Y., Wang, K., Li, W., Shi, J.-M., Osoro, E. K., Ullah, N., Zhou, Y., Ji, S.-R. C-reactive protein exacerbates epithelial-mesenchymal transition through Wnt/ß-catenin and ERK signaling in streptozocin-induced diabetic nephropathy.

Pdcd4 promotes lipid deposition by attenuating PPARα-mediated fatty acid oxidation in hepatocytes.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in hepatocytes. The involvement of programmed cell death 4 (Pdcd4) in inflammation and metabolic diseases has been widely reported. However, the precise regulatory role of Pdcd4 in hepatocytic lipid metabolism and NAFLD is not well known. RESEARCH DESIGN AND METHODS: We established a high-fat diet-induced NAFLD (HFD-NAFLD) rat model and a free fatty acids (FFAs)-treated cell model, and analyzed the expression and distribution of PDCD4. The lentivirus for Pdcd4 knockout and the vector for Pdcd4 overexpression were used to alter Pdcd4 expression in BRL 3A cells. Thereafter, lipid accumulation, FA metabolic gene expression, and peroxisome proliferator-activated receptor alpha (Pparα)-dependent peroxisomal ß-oxidation-related gene expression, especially that of the critical transcription factors and enzymes acyl-CoA oxidases 1-3 (Acox1-3), were detected both at the mRNA and protein levels. RESULTS: PDCD4 expression increased and it was mainly distributed in hepatocyte nuclei of the HFD-NAFLD rats. as well as the FFAs-treated CBRH-7919 and BRL 3A cell lines. Pdcd4 knockout significantly suppressed FFAs-induced lipid accumulation, and Pdcd4 overexpression accelerated FFAs-induced lipid accumulation in hepatocytes. Mechanistically, Pdcd4 negatively regulated the expression Pparα and Acox1-3. In addition, rescue experiments confirmed that Pparα knockdown could attenuate the expression of Acox1-3 in Pdcd4 knockout cells, which ultimately restored lipid deposition to normal levels. PPARα expression decreased in the liver of the HFD-NAFLD rats. The enrichment of PDCD4 in hepatocyte nuclei correlated with lower PPARα expression after FFAs treatment in vitro. CONCLUSION: Our results indicate that the abundance of PDCD4 under high-fat conditions facilitates hepatocellular lipid accumulation by decreasing PPARα-dependent FA peroxisomal ß-oxidation.

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.

Long Noncoding RNA lnc-HC Regulates PPARγ-Mediated Hepatic Lipid Metabolism through miR-130b-3p.

Nonalcoholic fatty liver disease (NAFLD) is due to the excessive lipid accumulation within hepatocytes. Metabolic nuclear receptors (MNRs) play great roles in lipid homeostasis. We have identified a novel long noncoding RNA (lncRNA), lnc-HC, which regulates hepatocytic cholesterol metabolism through reducing Cyp7a1 and Abca1 expression. Here, we further elucidate its roles in hepatic fatty acid and triglyceride (TG) metabolism through a novel lncRNA regulatory mechanism. The most prominent target of lnc-HC identified by in vitro study is PPARγ. Further studies revealed that lnc-HC negatively regulates PPARγ at both the mRNA and protein levels and suppresses hepatocytic lipid droplet formation. Importantly, the function of lnc-HC in regulating PPARγ expression depends on modulating miR-130b-3p expression from the transcriptional to the post-transcriptional level, not through lncRNA's critical modulating patterns. In vivo, the reduction of lnc-HC expression significantly decreases miR-130b-3p expression, induces PPARγ expression, and increases TG concentration in rat livers with hyperlipidemia. These findings further help in understanding the regulatory pattern of lnc-HC in hepatic lipid metabolism and might present a possible therapeutic target for improving lipid homeostasis.