TY - JOUR
T1 - Parathyroid hormone controls paracellular Ca2+ transport in the thick ascending limb by regulating the tight-junction protein Claudin14
AU - Sato, Tadatoshi
AU - Courbebaisse, Marie
AU - Ide, Noriko
AU - Fan, Yi
AU - Hanai, Jun Ichi
AU - Kaludjerovic, Jovana
AU - Densmore, Michael J.
AU - Yuan, Quan
AU - Toka, Hakan R.
AU - Pollak, Martin R.
AU - Hou, Jianghui
AU - Lanske, Beate
N1 - Funding Information:
We thank Tatsuya Kobayashi (Massachusetts General Hospital) for providing PTH1R flox mice, Thomas J. Gardella (Massachusetts General Hospital) for providing pcDNA3-hPTH1R-DsRed plasmid, Henry Kronenberg (Massachusetts General Hospital) for helpful discussion, and all of the B.L. laboratory members for scientific discussion. This study was supported by NIH Grant DK097105. T.S was supported, in part, by the Harvard School of Dental Medicine Dean's Scholarship and the Uehara Memorial Foundation Research Fellowship.
PY - 2017/4/18
Y1 - 2017/4/18
N2 - Renal Ca2+ reabsorption is essential for maintaining systemic Ca2+ homeostasis and is tightly regulated through the parathyroid hormone (PTH)/PTHrP receptor (PTH1R) signaling pathway. We investigated the role of PTH1R in the kidney by generating a mouse model with targeted deletion of PTH1R in the thick ascending limb of Henle (TAL) and in distal convoluted tubules (DCTs): Ksp-cre;Pth1rfl/fl. Mutant mice exhibited hypercalciuria and had lower serum calcium and markedly increased serum PTH levels. Unexpectedly, proteins involved in transcellular Ca2+ reabsorption in DCTs were not decreased. However, claudin14 (Cldn14), an inhibitory factor of the paracellular Ca2+ transport in the TAL, was significantly increased. Analyses by flow cytometry as well as the use of Cldn14-lacZ knock-in reportermice confirmed increased Cldn14 expression and promoter activity in the TAL of Ksp-cre;Pth1rfl/fl mice. Moreover, PTH treatment of HEK293 cells stably transfected with CLDN14-GFP, together with PTH1R, induced cytosolic translocation of CLDN14 from the tight junction. Furthermore, mice with high serum PTH levels, regardless of high or low serum calcium, demonstrated that PTH/PTH1R signaling exerts a suppressive effect on Cldn14. We therefore conclude that PTH1R signaling directly and indirectly regulates the paracellular Ca2+ transport pathway by modulating Cldn14 expression in the TAL. Finally, systemic deletion of Cldn14 completely rescued the hypercalciuric and lower serum calcium phenotype in Ksp-cre;Pth1rfl/fl mice, emphasizing the importance of PTH in inhibiting Cldn14. Consequently, suppressing CLDN14 could provide a potential treatment to correct urinary Ca2+ loss, particularly in patients with hypoparathyroidism.
AB - Renal Ca2+ reabsorption is essential for maintaining systemic Ca2+ homeostasis and is tightly regulated through the parathyroid hormone (PTH)/PTHrP receptor (PTH1R) signaling pathway. We investigated the role of PTH1R in the kidney by generating a mouse model with targeted deletion of PTH1R in the thick ascending limb of Henle (TAL) and in distal convoluted tubules (DCTs): Ksp-cre;Pth1rfl/fl. Mutant mice exhibited hypercalciuria and had lower serum calcium and markedly increased serum PTH levels. Unexpectedly, proteins involved in transcellular Ca2+ reabsorption in DCTs were not decreased. However, claudin14 (Cldn14), an inhibitory factor of the paracellular Ca2+ transport in the TAL, was significantly increased. Analyses by flow cytometry as well as the use of Cldn14-lacZ knock-in reportermice confirmed increased Cldn14 expression and promoter activity in the TAL of Ksp-cre;Pth1rfl/fl mice. Moreover, PTH treatment of HEK293 cells stably transfected with CLDN14-GFP, together with PTH1R, induced cytosolic translocation of CLDN14 from the tight junction. Furthermore, mice with high serum PTH levels, regardless of high or low serum calcium, demonstrated that PTH/PTH1R signaling exerts a suppressive effect on Cldn14. We therefore conclude that PTH1R signaling directly and indirectly regulates the paracellular Ca2+ transport pathway by modulating Cldn14 expression in the TAL. Finally, systemic deletion of Cldn14 completely rescued the hypercalciuric and lower serum calcium phenotype in Ksp-cre;Pth1rfl/fl mice, emphasizing the importance of PTH in inhibiting Cldn14. Consequently, suppressing CLDN14 could provide a potential treatment to correct urinary Ca2+ loss, particularly in patients with hypoparathyroidism.
UR - http://www.scopus.com/inward/record.url?scp=85017665568&partnerID=8YFLogxK
U2 - 10.1073/pnas.1616733114
DO - 10.1073/pnas.1616733114
M3 - Article
C2 - 28373577
AN - SCOPUS:85017665568
SN - 0027-8424
VL - 114
SP - E3344-E3353
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 16
ER -