UNASSIGNED: Peritoneal fibrosis remains a serious complication of long-term peritoneal dialysis (PD) leading to peritoneal membrane ultrafiltration failure. Epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is a key process of peritoneal fibrosis. Curcumin has been previously shown to inhibit EMT of renal tubular epithelial cells and prevent renal fibrosis. There are only limited reports on inhibition of PMCs-EMT by curcumin. This study aimed to investigate the effect of curcumin on the regulation of EMT and related pathway in PMCs treated with glucose-based PD.
UNASSIGNED: EMT of human peritoneal mesothelial cells (HMrSV5) was induced with glucose-based peritoneal dialysis solutions (PDS). Cells were divided into a control group, PDS group, and PDS group receiving varied concentrations of curcumin. Cell Counting Kit-8 (CCK-8) assay was used to measure cell viability, and a transwell migration assay was used to verify the capacity of curcumin to inhibit EMT in HMrSV5 cells. Real-time quantitative PCR and western blot were used to detect the expression of genes and proteins associated with the EMT.
UNASSIGNED: High glucose PDS decreased cell viability and increased migratory capacity. Curcumin reversed growth inhibition and migration capability of human peritoneal mesothelial cells (HPMCs). In HMrSV5 cells, high glucose PDS also decreased expression of epithelial markers, and increased expression of mesenchymal markers, a characteristic of EMT. Real-time RT-PCR and western blot revealed that, compared to the 4.25% Dianeal treated cells, curcumin treatment resulted in increased expression of E-cadherin (epithelial marker), and decreased expression of α-SMA (mesenchymal markers) (P < 0.05). Furthermore, curcumin reduced mRNA expression of two extracellular matrix protein, collagen I and fibronectin. Curcumin also reduced TGF-β1 mRNA and supernatant TGF-β1 protein content in the PDS-treated HMrSV5 cells (P < 0.05). Furthermore, it significantly reduced protein expression of p-TAK1, p-JNK and p-p38 in PDS-treated HMrSV5 cells.
UNASSIGNED: Our results demonstrate that curcumin showed an obvious protective effect on PDS-induced EMT of HMrSV5 cells and suggest implication of the TAK1, p38 and JNK pathway in mediating the effects of curcumin in EMT of MCs.

Renal cell carcinoma (RCC) is a common kidney tumor in adults. The role of miR-486-5p in RCC is unknown. The aim of our study was to identify new targets regulated by miR-486-5p in RCC, to obtain a deeper insight into the network and to better understand the role of these microRNAs and their targets in carcinogenesis of RCC. We performed a series of tests and found consistently lower expression levels of miR-486-5p in kidney cancer cells. Restoration of miR-486-5p expression in RCC cells could lead to the suppression of cell proliferation and the increase of cell apoptosis. Further studies demonstrated that TGF-β-activated kinase 1 was a target gene of miR-486-5p in kidney cancer cells. It was also shown that C-C motif chemokine ligand 2 (CCL2) from tumor-associated macrophages downregulated miR-486-5p expression, and miR-486-5p inhibited RCC cell proliferation and apoptosis resistance induced by CCL2. The study demonstrates that there are potential diagnosis and therapy values of miR-486-5p in RCC.

microRNAs (miRNAs) have been shown to be closely involved in the control of melanogenesis and hair colour in mammals. Previous data also indicate that miR-143 regulates cell growth in melanoma. Here, we aimed to investigate the role of miR-143-5p in alpaca melanocytes. We found that miR-143-5p was highly expressed in the cytoplasm of alpaca melanocytes as demonstrated by an in situ hybridization assay. Prediction analysis revealed that miR-143-5p could regulate TGF-β-activated kinase 1 (TAK1) expression, which we confirmed by luciferase reporter assay, indicating that miR-143-5p controls TAK1 expression by directly targeting its 3\' untranslated region (UTR). miR-143-5p overexpression decreased TAK1 expression, which led to increased melanocyte migration and proliferation, and downregulation of microphthalmia-associated transcription factor (MITF), which regulates melanin production. These results support a functional role for miR-143-5p in regulating alpaca melanocyte migration, proliferation and melanogenesis through direct targeting of TAK1.

Cardiac hypertrophy and associated heart fibrosis remain a major cause of death worldwide. Phytochemicals have gained attention as alternative therapeutics for managing cardiovascular diseases. These include the extract from the plant Terminalia arjuna, which is a popular cardioprotectant and may prevent or slow progression of pathological hypertrophy to heart failure. Here, we investigated the mode of action of a principal bioactive T. arjuna compound, arjunolic acid (AA), in ameliorating hemodynamic load-induced cardiac fibrosis and identified its intracellular target. Our data revealed that AA significantly represses collagen expression and improves cardiac function during hypertrophy. We found that AA binds to and stabilizes the ligand-binding domain of peroxisome proliferator-activated receptor α (PPARα) and increases its expression during cardiac hypertrophy. PPARα knockdown during AA treatment in hypertrophy samples, including angiotensin II-treated adult cardiac fibroblasts and renal artery-ligated rat heart, suggests that AA-driven cardioprotection primarily arises from PPARα agonism. Moreover, AA-induced PPARα up-regulation leads to repression of TGF-β signaling, specifically by inhibiting TGF-β-activated kinase1 (TAK1) phosphorylation. We observed that PPARα directly interacts with TAK1, predominantly via PPARα N-terminal transactivation domain (AF-1) thereby masking the TAK1 kinase domain. The AA-induced PPARα-bound TAK1 level thereby shows inverse correlation with the phosphorylation level of TAK1 and subsequent reduction in p38 MAPK and NF-κBp65 activation, ultimately culminating in amelioration of excess collagen synthesis in cardiac hypertrophy. In conclusion, our findings unravel the mechanism of AA action in regressing hypertrophy-associated cardiac fibrosis by assigning a role of AA as a PPARα agonist that inactivates non-canonical TGF-β signaling.

Renal cell carcinoma (RCC) is common renal malignancy within poor prognosis. TGF-β-activated kinase 1 (TAK1) plays vital roles in cell survival, apoptosis-resistance and carcinogenesis through regulating nuclear factor-κB (NF-κB) and other cancer-related pathways. Here we found that TAK1 inhibitors (LYTAK1, 5Z-7-oxozeanol (5Z) and NG-25) suppressed NF-κB activation and RCC cell (786-O and A489 lines) survival. TAK1 inhibitors induced apoptotic cytotoxicity against RCC cells, which was largely inhibited by the broad or specific caspase inhibitors. Further, shRNA-mediated partial depletion of TAK1 reduced 786-O cell viability whiling activating apoptosis. Significantly, TAK1 was over-expressed in human RCC tissues, and its level was correlated with phosphorylated NF-κB. Finally, kinase inhibition or genetic depletion of TAK1 enhanced the activity of vinblastine sulfate (VLB) in RCC cells. Together, these results suggest that TAK1 may be an important oncogene or an effective target for RCC intervention.