HNF1 AND HYPERTENSIVE NEPHROPATHY

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 51; no. 6; pp. 1583 - 1589
• Main Authors: Dmitrieva, Renata I., Hinojos, Cruz A., Boerwinkle, Eric, Braun, Michael C., Fornage, Myriam, Doris, Peter A.
• Format: Journal Article
• Language: English
• Published: 28.04.2008
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.108.110163

Hypertension in SHR is associated with renal redox stress and we hypothesized that nephropathy arises in SHR-A3 from altered capacity to mitigate redox stress compared with nephropathy-resistant SHR lines. We measured renal expression of redox genes in distinct lines of the spontaneously hypertensive rat (SHR-A3, SHR-B2, SHR-C) and the normotensive WKY strain. The SHR lines differ in either resisting (SHR-B2, SHR-C) or experiencing hypertensive nephropathy (SHR-A3). Immediately prior to the emergence of hypertensive renal injury expression of redox genes in SHR-A3 was profoundly altered compared with the injury-resistant SHR lines and WKY. This change appeared to arise in anti-oxidant genes where 16 of 28 were expressed at 34.3% of the level in the reference strain (WKY). No such change was observed in the injury-resistant SHR lines. We analyzed occurrence of transcription factor matrices (TFM) in the promoters of the down-regulated antioxidant genes. In these genes, the HNF1 TFM was found to be nearly twice as likely to be present and the overall frequency of HNF1 sites was nearly 5 times higher, compared with HNF1 TFMs in anti-oxidant genes that were not down-regulated. We identified 35 other (non-redox) renal genes regulated by HNF1. These were also significantly down-regulated in SHR-A3, but not in SHR-B2 or SHR-C. Finally, expression of genes that comprise HNF1 (Tcf1, Tcf2 and Dcoh) was also down-regulated in SHR-A3. The present experiments uncover a major change in transcriptional control by HNF1 that affects redox and other genes and precedes emergence of hypertensive renal injury.