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Quantitative proteomics of hypokalemia induced nephrogenic diabetes insipidus
Author(s) -
Khositseth Sookkasem,
Somparn Poorichaya,
Uawithya Panapat,
Chen ShuHui
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1111.5
Subject(s) - aquaporin 2 , nephrogenic diabetes insipidus , hypokalemia , chemistry , medicine , kidney , endocrinology , biology , engineering , inlet , mechanical engineering , water channel
Nephrogenic diabetes insipidus (NDI) can be caused by hypokalemia. The effect of early onset NDI due to hypokalemia was studied using proteomics profiling of rat kidney medullary collecting duct (IMCD). Rats were fed with potassium‐free or regular diet. IMCDs were isolated on day1, protein extracts were subjected to in‐gel trypsin digestion and analysis by label‐free quantitative mass spectrometry. A total of 2,477 peptides corresponding to 821 proteins were identified, among which 189 proteins had significant change in abundance. Gene Ontology analysis revealed that hypokalemia significantly down‐regulated proteins from adherens junction (Iqgap1, Rhoa, Vcl, Actn4, Ctnnd1, Ctnnb1), tight junction (Gbai1, Actn4, Myh10, Sptan1, Ctnnb1) and actin cytoskeletal organization (Itgb1, Cfl1, Vcl, Myh10, Ezr) (P<0.05). Immunoblotting demonstrated a 30% decrease of β‐catenin (P<0.05), 23% decrease of total Aqp2 (P<0.05), 60% decrease of pS256‐Aqp2 (P<0.001), 36.4 % decrease of pS261‐Aqp2 (P<0.05), unchanged of total Slc14a2, and pS486‐UTA1 abundances. In conclusion, this is the first report of the involvement of adherens junction, tight junction and actin cytoskeletal organization in hypokalemia‐induced early onset NDI. Phosphopeptides of Aqp2 known to play important roles in urine concentrating mechanism were changed in abundance in hypokalemia‐induced NDI.