Regulation of Embryonic Kidney Branching Morphogenesis and Glomerular Development by KISS1 Receptor (Gpr54) through NFAT2- and Sp1-mediated Bmp7 Expression

Tingfang Yi,Kunrong Tan,Sung-Gook Cho,Ying Wang,Jian Luo,Wenzheng Zhang,Dali Li,Mingyao Liu

doi:10.1074/jbc.m110.130740

Abstract

G-protein-coupled receptor 54 (Gpr54, KISS1 receptor) plays critical roles in puberty regulation, tumor metastasis suppression, and vasoconstriction. Bone morphogenetic protein-7 (Bmp7) is required for kidney organogenesis. However, whether Gpr54 is involved in embryonic kidney development and how Bmp7 expression is regulated in the kidney are largely unknown. Here we report that Gpr54 deletion leads to kidney branching morphogenesis and glomerular development retardation in embryonic kidneys in vivo and in explanted kidneys in vitro. Gpr54 inactivation results in a high risk of low glomerular number in adult kidneys. Gpr54 is expressed in condensed mesenchyme at E12.5 and epithelial cells of proximal and distal tubules and collecting ducts at E17.5 and P0 mouse kidney. Deletion of Gpr54 decreases Bmp7 expression and Smad1 phosphorylation in the developing kidney. Using chromatin immunoprecipitation and luciferase assays, we demonstrate that Gpr54 regulates NFAT2- and Sp1-mediated Bmp7 transcription. Furthermore, we show that NFAT2 cooperates with Sp1 to promote Bmp7 transcription activation. Together, these data suggest that Gpr54 regulates Bmp7 expression through NFAT2 and Sp1 and plays an important role in embryonic kidney branching morphogenesis and glomerular development.

Highlights

Grant 1R01CA106479 (NCI). 1 To whom correspondence should be addressed: Institute of Biosciences and gonadal axis during puberty and reproductive development (18 –28)
To understand whether G-protein-coupled receptor-54 (Gpr54) plays a role in embryonic kidney branching morphogenesis, we examined the size and ureteric bud number of E12.5 wild type and Gpr54Ϫ/Ϫ kidneys
Gpr54 deletion leads to a smaller kidney in size (Fig. 1, A and B) and a dramatically reduced ureteric bud number at E12.5 (Fig. 1, C–E), indicating that Gpr54 is involved in normal kidney branching morphogenesis

Summary

The abbreviations used are

Bone morphogenetic protein; HPF, high performance field; RT, reverse transcription; Q-PCR, quantitative PCR; CsA, cyclosporin A; CHIP, chromatin immunoprecipitation; PBS, phosphatebuffered saline. Gpr Regulates Kidney Development and Bmp Expression roles in ureteric bud outgrowth, ureteric bud branching, tubule maintenance, and nephrogenesis [42,43,44]. Bmp is expressed in both ureteric epithelium and mesenchyme of early embryonic kidneys and distal tubules in later stage [46, 49]. A high level of Bmp mRNA expression has been reported in the tubules of the outer medulla, adventitia of renal arteries, and epithelial cell layer of the renal pelvis and the ureter [52]. We investigate the roles of Gpr in embryonic kidney branching morphogenesis and glomerular development and elucidate how Gpr regulates Bmp expression in the kidney. We demonstrate that Gpr regulates Bmp expression through the cooperative effect of NFAT2 and Sp1 in the developing kidney

EXPERIMENTAL PROCEDURES

RESULTS

DISCUSSION