title: Null mutations at the p66 and bradykinin 2 receptor loci induce divergent phenotypes in the diabetic kidney.
abstract: Candidate genes have been identified that confer increased risk for diabetic glomerulosclerosis (DG). Mice heterozygous for the Akita (Ins2(+/C96Y)) diabetogenic mutation with a second mutation introduced at the bradykinin 2 receptor (B2R(-/-)) locus express a disease phenotype that approximates human DG. Src homology 2 domain transforming protein 1 (p66) controls mitochondrial metabolism and cellular responses to oxidative stress, aging, and apoptosis. We generated p66-null Akita mice to test whether inactivating mutations at the p66 locus will rescue kidneys of Akita mice from disease-causing mutations at the Ins2 and B2R loci. Here we show null mutations at the p66 and B2R loci interact with the Akita (Ins2(+/C96Y)) mutation, independently and in combination, inducing divergent phenotypes in the kidney. The B2R(-/-) mutation induces detrimental phenotypes, as judged by increased systemic and renal levels of oxidative stress, histology, and urine albumin excretion, whereas the p66-null mutation confers a powerful protection phenotype. To elucidate the mechanism(s) of the protection phenotype, we turned to our in vitro system. Experiments with cultured podocytes revealed previously unrecognized cross talk between p66 and the redox-sensitive transcription factor p53 that controls hyperglycemia-induced ROS metabolism, transcription of p53 target genes (angiotensinogen, angiotensin II type-1 receptor, and bax), angiotensin II generation, and apoptosis. RNA-interference targeting p66 inhibits all of the above. Finally, protein levels of p53 target genes were upregulated in kidneys of Akita mice but unchanged in p66-null Akita mice. Taken together, p66 is a potential molecular target for therapeutic intervention in DG.
authors.affiliation: Institute for Translational Research, Nephrology Research Laboratory, Ochsner Health Foundation, Dept. of Nephrology, New Orleans, LA 70121, USA.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Vashistha
authors.forename: Pravin C
authors.initials: PC
authors.lastname: Singhal
authors.forename: Ashwani
authors.initials: A
authors.lastname: Malhotra
authors.forename: Mohammad
authors.initials: M
authors.lastname: Husain
authors.forename: Peter
authors.initials: P
authors.lastname: Mathieson
authors.forename: Moin A
authors.initials: MA
authors.lastname: Saleem
authors.forename: Cyril
authors.initials: C
authors.lastname: Kuriakose
authors.forename: Surya
authors.initials: S
authors.lastname: Seshan
authors.forename: Anna
authors.initials: A
authors.lastname: Wilk
authors.forename: Luis
authors.initials: L
authors.lastname: Delvalle
authors.forename: Francesca
authors.initials: F
authors.lastname: Peruzzi
authors.forename: Marco
authors.initials: M
authors.lastname: Giorgio
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Pelicci
authors.forename: Oliver
authors.initials: O
authors.lastname: Smithies
authors.forename: Hyung-Suk
authors.initials: HS
authors.lastname: Kim
authors.forename: Masao
authors.initials: M
authors.lastname: Kakoki
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Reiss
authors.forename: Leonard G
authors.initials: LG
authors.lastname: Meggs
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D006943:Hyperglycemia / Q000378:metabolism / Q000473:pathology; D066298:In Vitro Techniques; D007328:Insulin / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D050199:Podocytes / Q000378:metabolism / Q000473:pathology; D043782:Receptor, Bradykinin B2 / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: C561967:Ins2 protein, mouse; D007328:Insulin; D043782:Receptor, Bradykinin B2; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016159:Tumor Suppressor Protein p53