CCN2/CTGF increases expression of miR-302 microRNAs, which target the TGFβ type II receptor with implications for nephropathic cell phenotypes

Abstract

SummarySignalling interplay between transforming growth factor-b (TGFb) and CCN2 [also called connective tissue growth factor (CTGF)] plays a crucial role in the progression of diabetic nephropathy and has been implicated in cellular differentiation. To investigate the potential role of microRNAs (miRNAs) in the mediation of this signalling network, we performed miRNA screening in mesangial cells treated with recombinant human CCN2. Analysis revealed a cohort of 22 miRNAs differentially expressed by twofold or more, including members of the miR-302 family. Target analysis of miRNA to 39-untranslated regions (39-UTRs) identified TGFb receptor II (TbRII) as a potential miR-302 target. In mesangial cells, decreased TbRII expression was confirmed in response to CCN2 together with increased expression of miR-302d. TbRII was confirmed as an miR-302 target, and inhibition of miR-302d was sufficient to attenuate the effect of CCN2 on TbRII. Data from the European Renal cDNA Biopsy Bank revealed decreased TbRII in diabetic patients, suggesting pathophysiological significance. In a mouse model of fibrosis (UUO), miR-302d was increased, with decreased TbRII expression and aberrant signalling, suggesting relevance in chronic fibrosis. miR-302d decreased TGFb-induced epithelial mesenchymal transition (EMT) in renal HKC8 epithelial cells and attenuated TGFb-induced mesangial production of fibronectin and thrombospondin. In summary, we demonstrate a new mode of regulation of TGFb by CCN2, and conclude that the miR-302 family has a role in regulating growth factor signalling pathways, with implications for nephropathic cell fate transitions.

Anti-Connective Tissue Growth Factor Antibody Treatment Reduces Extracellular Matrix Production in Trabecular Meshwork and Lamina Cribrosa Cells

“…In summary, recent studies have described the complex relationship between increased CTGF expression, TGFb activity, and fibrotic pathogenesis, 45,69,70 highlighting the complex signaling interplay between CTGF and TGFb that results in increased production of ECM components. It is now clear that the fibrotic/permissive microenvironment in the glaucoma AqH contains sizable quantities of both factors.…”

miR302a-3p May Modulate Renal Epithelial-Mesenchymal Transition in Diabetic Kidney Disease by Targeting ZEB1

“…It was reported that miR-302 could suppress the TGF-β-induced EMT of human epithelial cells, through regulating the expression of E-cadherin and ZO-1 [20]. In renal HKC8 epithelial cells, miR-302d decreased TGF-β-induced EMT and attenuated TGF-β-induced mesangial production of fibronectin and thrombospondin by negative regulation of TbRII receptor [35]. In human prostate cancer cells (PC-3 cells), dsEcad640, which is a siRNA, suppressed the expression of ZEB1 mRNA and upregulated the expression of E-cadherin through combination with ZEB1 coding sequence, and dsEcad640 and miR-302a have the same seed sequence [20].…”

Signaling Receptors for TGF-β Family Members

“…TbRII down-regulation enhances the dedifferentiation process and promotes a mesenchymal to epithelial transition that is required for the establishment of the stem cells in vitro. In a different context, miR-302, which is induced by connective tissue growth factor ([CTGF] also called CCN2), targets TbRII mRNA and thereby inhibits kidney fibrosis (Faherty et al 2012). On the other hand, during progression of kidney fibrosis, TGF-b signaling transcriptionally represses the miR-let-7b (commonly known as let-7b); miR-let-7b targets and down-regulates TbRI mRNA expression, and, thus, miR-let-7b repression by TGF-b causes TbRI induction and enhanced signaling in kidneys where fibrosis develops Wang et al 2014).…”