TY - JOUR
T1 - Identifying the localization and exploring a functional role for Gprc5c in the kidney
AU - Rajkumar, Premraj
AU - Cha, Boyoung
AU - Yin, Jianyi
AU - Arend, Lois J.
AU - Pǎunescu, Teodor G.
AU - Hirabayashi, Yoshio
AU - Donowitz, Mark
AU - Pluznick, Jennifer L.
N1 - Funding Information:
The authors thank Gregory Blass and Alexander Staru-schenko (Medical College of Wisconsin, Milwaukee, WI, USA) and P. Richard Grimm and Paul Welling (University of Maryland, College Park, MD, USA) for sharing their protocols for urine ammonia measurement and blood collection from the abdominal aorta, respectively. The authors are grateful to Peter S. Aronson (Yale University, New Haven, CT, USA) for sharing the Megalin antibody. The authors are also grateful to the members of the J.L.P. and M.D. laboratories for their helpful discussions. This work was supported by U.S. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases Grant R00-DK081610 (to J.L.P.), and a National Kidney Foundation of Maryland Mini-Grant (to P.R.). The authors declare no conflicts of interest.
Funding Information:
The authors thank Gregory Blass and Alexander Staruschenko (Medical College of Wisconsin, Milwaukee, WI, USA) and P. Richard Grimm and Paul Welling (University of Maryland, College Park, MD, USA) for sharing their protocols for urine ammonia measurement and blood collection from the abdominal aorta, respectively. The authors are grateful to Peter S. Aronson (Yale University, New Haven, CT, USA) for sharing the Megalin antibody. The authors are also grateful to the members of the J.L.P. and M.D. laboratories for their helpful discussions. This work was supported by U.S. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases Grant R00-DK081610 (to J.L.P.), and a National Kidney Foundation of Maryland Mini-Grant (to P.R.). The authors declare no conflicts of interest.
Publisher Copyright:
© 2018 FASEB.
PY - 2018/4
Y1 - 2018/4
N2 - The investigation of orphan GPCRs (GPRs) has the potential to uncover novel insights into whole animal physiology. In this study, our goal was to determine the renal localization of Gprc5c, a receptor that we previously reported to be highly expressed in murine whole kidney, and to examine physiologic parameters in Gprc5c knockout (KO)mice to gain insight into function. Gprc5c localized to the apical membrane of renal proximal tubules (PTs) inmice, rats, and humans. With the comparison of Gprc5cwild-type (WT) and KO mice, we found that Gprc5c KO mice have altered acid-base homeostasis. Specifically, Gprc5c KO mice have lower blood pH and higher urine pH compared with WT mice, with a reduced level of titratable acids in their urine. In an in vitro GPCR internalization assay, we observed that Gprc5c internalization (an index of activation) was triggered by alkaline extracellular pH. Furthermore, with the use of an in vitro BCECF assay, we observed that Gprc5c increases Na+/H+ exchanger 3 (NHE3) activity at alkaline pH. We also find that the NHE3 activity is reduced in Gprc5c KOmice by 2 photon imaging in seminaphthorhodafluors (SNARF)-4F-loaded kidney sections. NHE3 is a primary contributor to apical transport of H+ in the renal PT. Together, these data imply that Gprc5c modulates the renal contribution to systemic pH homeostasis, at least in part, by taking part in the regulation of NHE3.
AB - The investigation of orphan GPCRs (GPRs) has the potential to uncover novel insights into whole animal physiology. In this study, our goal was to determine the renal localization of Gprc5c, a receptor that we previously reported to be highly expressed in murine whole kidney, and to examine physiologic parameters in Gprc5c knockout (KO)mice to gain insight into function. Gprc5c localized to the apical membrane of renal proximal tubules (PTs) inmice, rats, and humans. With the comparison of Gprc5cwild-type (WT) and KO mice, we found that Gprc5c KO mice have altered acid-base homeostasis. Specifically, Gprc5c KO mice have lower blood pH and higher urine pH compared with WT mice, with a reduced level of titratable acids in their urine. In an in vitro GPCR internalization assay, we observed that Gprc5c internalization (an index of activation) was triggered by alkaline extracellular pH. Furthermore, with the use of an in vitro BCECF assay, we observed that Gprc5c increases Na+/H+ exchanger 3 (NHE3) activity at alkaline pH. We also find that the NHE3 activity is reduced in Gprc5c KOmice by 2 photon imaging in seminaphthorhodafluors (SNARF)-4F-loaded kidney sections. NHE3 is a primary contributor to apical transport of H+ in the renal PT. Together, these data imply that Gprc5c modulates the renal contribution to systemic pH homeostasis, at least in part, by taking part in the regulation of NHE3.
KW - NHE3
KW - Ph regulation
KW - Proximal tubule
UR - http://www.scopus.com/inward/record.url?scp=85048672110&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85048672110&partnerID=8YFLogxK
U2 - 10.1096/fj.201700610RR
DO - 10.1096/fj.201700610RR
M3 - Article
C2 - 29196502
AN - SCOPUS:85048672110
SN - 0892-6638
VL - 32
SP - 2046
EP - 2059
JO - FASEB Journal
JF - FASEB Journal
IS - 4
ER -