miR-217 Mediates the Protective Effects of the Dopamine D2 Receptor on Fibrosis in Human Renal Proximal Tubule Cells

Abstract

Lack or downregulation of the dopamine D2 receptor (D2R) increases the vulnerability to renal inflammation independently of blood pressure in mice. Common single nucleotide polymorphisms (SNPs) rs 6276, 6277 and 1800497 in the human D2R gene are associated with decreased receptor expression/function, and hypertension. Human renal proximal tubule cells from subjects carrying these SNPs have decreased D2R expression and increased expression of pro-fibrotic factors and production of extracellular matrix proteins. We tested the hypothesis that the D2R mediates these effects by regulating microRNA expression. In cells carrying D2R SNPs, microRNAs (miRs)-217, -224, -335 and -1265 were downregulated while miR-1290 was upregulated more than 4-fold compared with those carrying D2R wild-type (WT) alleles. However, only miR-217 was directly regulated by D2R expression. In cells carrying D2R WT, miR-217 inhibitor increased the expression of TGFβ1, MMP3, FN1, and Col1a while miR-217 mimic had the opposite effect. In cells carrying D2R SNPs, miR-217 mimic also decreased the expression of TGFβ1 and its targets. Wnt5a, a miR-217 target, was increased in cells carrying D2R SNPs, and decreased by miR-217 mimic but increased by miR-217 inhibitor in both cell types. In cells carrying D2R WT, Wnt5a treatment increased TGFβ1 while silencing Ror2, a Wnt5a receptor, decreased TGFβ1 and blunted the Wnt5a-induced increase in cells carrying D2R WT. Our results show that renal proximal tubule cells from subjects carrying D2R SNPs resulting in D2R downregulation have increased TGFβ1 that is mediated by decreased regulation of the miR-217-Wnt5a-Ror2 pathway.

Renal rescue of dopamine D2 receptor function reverses renal injury and high blood pressure

“…These pathways mediate the increase in profibrotic factors in human renal proximal tubule cells bearing DRD2 SNPs associated with decreased DRD2 expression (17, 18). …”

“…Some common SNPs in the noncoding region of the human DRD2 gene are associated with decreased DRD2 expression and function, and some of these SNPs are associated with increased blood pressure or hypertension (20–24). Renal proximal tubule cells from human subjects carrying these polymorphisms express elevated levels of proinflammatory and profibrotic factors and markers of epithelial mesenchymal transition indicating that the DRD2 has protective effects in these cells (16, 17). We now show that (a) prolonged silencing of Drd2 expression, selectively in the kidney, increases renal inflammation and injury and blood pressure; (b) rescue of Drd2 expression selectively in the Drd2 -silenced kidney with adeno-associated virus (AAV) vectors provides sustained long-term DRD2 expression with minimal immunological consequences (25), reduces renal inflammation and injury, and normalizes the blood pressure; and (c) overexpression of DRD2 in the kidney ameliorates the renal injury induced by ischemia/reperfusion.…”

Mini-review: emerging roles of microRNAs in the pathophysiology of renal diseases

“…These findings demonstrate a negative regulatory role of miR-29b in collagen and extracellular matrix accumulation in hypertensive renal injury. Interestingly, recent work has implicated miR-217 in mediating the protective effects of the dopamine D2 receptor on fibrosis in renal tubular cells (45). Additionally, miR-192 and mir-324-3p may play a role in hypertensive nephropathy (150).…”

MicroRNA-217 regulates interstitial pneumonia via IL-6

“…MicroRNA-217 is closely related to inflammation and fibrosis. For example, miR-217 is involved in the protection of dopamine receptor D2 against fibrosis of proximal tubule cells [13]. miR-217 can affect the inflammatory response and fibrosis of glomerular mesangial cells through the Sirt1/HIF-1a signaling pathway [14].…”