Interaction of Sex Hormones and Dopamine D2 Receptor Polymorphisms in Human Renal Proximal Tubule Cells

Abstract

The renal inflammatory response can be modulated by the dopamine D2 receptor (D2R) subtype. The DRD2 gene is highly polymorphic in humans, and single nucleotide polymorphisms (SNPs), such as rs6276 and rs6277 ( DRD2 SNPs), decrease its expression and function. We hypothesized that the response of human renal proximal tubular cells (hRPTCs) to hormones in the culture medium differs by sex and DRD2 SNPs, leading to differences in the inflammatory response. We determined the effects of dihydrotestosterone (DHT) and estradiol (ES) on hRPTCs genotyped for the presence or absence of DRD2 SNPs. We studied four cell lines from males (M) and females (F) with wild-type (WT) DRD2 (M- DRD2 WT and F- DRD2 WT) and DRD2 SNPs (M- DRD2 SNPs and F- DRD2 SNPs). The cells were cultured in a medium containing charcoal-stripped fetal bovine serum (FBS) for 24 hours, without (control group, CG) and with dihydrotestosterone (DHT, 5 nM) or estradiol (ES, 20 nM). We quantified the renal protein expression (protein of interest/GAPDH) of proinflammatory and profibrotic factors and markers of injury and proliferation. DHT decreased the expression of transforming growth factor (TGF-β) by ≍50% in both M- DRD2 WT (0.4±0.1 vs. 1.0±0.2) and M- DRD2 SNPs (1.0±0.1 vs. 1.6±0.1) (n=5-6, p<0.05). However, there was no significant effect of DHT or ES on the expression of TGF-β in F- DRD2 WT and F- DRD2 SNPs. DHT did not affect the fibronectin 1 (FN1) expression in M- DRD2 WT and M- DRD2 SNPs. In F- DRD2 WT, DHT did not affect FN1 expression but decreased in F- DRD2 SNPs (0.9±0.1 vs. 1.7±0.1, n=6, p<0.05). Similar to DHT, ES did not affect FN1 expression in M- DRD2 WT. However, ES decreased FN1 by 50% in M- DRD2 SNPs (0.5±0.1 vs. 1.1±0.1, n=6, p<0.05). Similar to the studies in males, ES did not affect FN1 expression in F- DRD2 WT but also decreased FN1 (1.0±0.1 vs. 1.7±0.1, n=6, p<0.05) in F-DRD2 SNPs. Neither DHT nor ES affected the expression of Kidney Injury Molecule-1 (KIM-1) in M- DRD2 WT. However, in M- DRD2 SNPs, both DHT and ES decreased KIM-1 (1.4±0.2 vs. 1.8±0.2 and 1.1±0.1 vs. 1.8±0.2, respectively; n=5, p<0.05). Unlike in M- DRD2-WT, in F- DRD2 WT, ES increased KIM-1 expression (1.0±0.2 vs. 0.52±0.05, n=5, p<0.05), while DHT had no significant effect. Unlike in M- DRD2 SNPs, where both DHT and ES decreased KIM-1, in F- DRD2 SNPs, neither DHT nor ES affected KIM-1. DHT did not affect the expression of Ki67 in M- DRD2 WT. However, in M- DRD2 SNPs, DHT decreased Ki67 expression (0.60±0.08 vs. 1.6±0.2, n=6, p<0.05). Similar to M- DRD2-WT, DHT did not affect Ki67 expression in F- DRD2-WT. ES also did not affect Ki67 expression in M- DRD2 WT but decreased Ki67 expression in M-DRD2 SNPs (0.91± 0.18 vs. 1.6±0.2, n=6, p<0.05). Similar to the male data, the treatment with ES did not affect the Ki67 expression in F- DRD2 WT but decreased Ki67 expression in F- DRD2 SNPs (1.5±0.2 vs. 0.9±0.1, n=6, p<0.05). Our results demonstrate similarities (FN1 and Ki67) and differences (TGF-β and KIM-1) in profibrotic and proliferation markers expressed in hRPTCs between males and females. These differences are more pronounced in cell lines expressing DRD2 SNPs than those expressing the DRD2 WT. While both DHT and ES decreased KIM-1 expression in males with DRD2 polymorphisms, they had no effect in females with DRD2 polymorphisms. These results indicate a complex interaction of the effect of hormones and DRD2 polymorphisms in regulating the inflammatory response in hRPTCs. Their roles in regulating renal physiology and blood pressure remain to be defined. R01 DK039308 P01 HL068686 R01 HL023081 R37 HL023081 R01 DK119652/ NIH HH/ US. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.