Molecular genetic study of congenital nephrogenic diabetes insipidus and rescue of mutant vasopressin V2 receptor by chemical chaperones.
OBJECTIVE
X-linked nephrogenic diabetes insipidus is a rare disease caused by mutations in the arginine vasopressin V2 receptor (AVPR2) gene, which encodes vasopressin V2 receptor (V2R). More than a half of reported mutations in AVPR2 are missense mutations, and a large number of missense mutant receptors fail to fold properly and therefore are not routed to the cell surface.


METHODS
We analysed the AVPR2 gene in 14 unrelated patients with X-linked nephrogenic diabetes insipidus, and found 13 different mutations including eight missense point mutations. The cellular expression patterns of three missense mutant (A98P, L274P and R113W) and wild-type V2R were determined in transfected COS-7 cells.


RESULTS
In contrast to wild-type V2R, the cell-surface expressions of mutant receptors were totally (A98P and L274P) or partially (R113W) absent. Instead, they were retained intracellularly. However, treatment of cells with two chemical chaperones (100 mmol/L trimethylamine oxide or 2% dimethyl sulfoxide) or incubation at 26 degrees C restored the cell-surface expressions of mutant receptors.


CONCLUSIONS
These data show that some chemical chaperones correct the mistrafficking of misfolded A98P, L274P and R113W V2R. Thus, we believe that a therapeutic strategy based on chemical chaperones in patients with these mutations is worth trying.
Cheong
Hae Il
HI
Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea. cheonghi@snu.ac.kr
Cho
Hee Yeon
HY
Park
Hye Won
HW
Ha
Il Soo
IS
Choi
Yong
Y
D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D018500:Diabetes Insipidus, Nephrogenic / Q000235:genetics / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008744:Methylamines / Q000494:pharmacology*; D018832:Molecular Chaperones / Q000494:pharmacology; D009154:Mutation; D020125:Mutation, Missense; D017354:Point Mutation; D017510:Protein Folding; D021381:Protein Transport / Q000187:drug effects; D017483:Receptors, Vasopressin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014162:Transfection
D008744:Methylamines; D018832:Molecular Chaperones; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; C023336:trimethylamine; D004121:Dimethyl Sulfoxide