title: Cyst formation in kidney via B-Raf signaling in the PKD2 transgenic mice.
abstract: The pathogenic mechanisms of human autosomal dominant polycystic kidney disease (ADPKD) have been well known to include the mutational inactivation of PKD2. Although haploinsufficiency and loss of heterozygosity at the Pkd2 locus can cause cyst formation in mice, polycystin-2 is frequently expressed in the renal cyst of human ADPKD, raising the possibility that deregulated activation of PKD2 may be associated with the cystogenesis of human ADPKD. To determine whether increased PKD2 expression is physiologically pathogenic, we generated PKD2-overexpressing transgenic mice. These mice developed typical renal cysts and an increase of proliferation and apoptosis, which are reflective of the human ADPKD phenotype. These manifestations were first observed at six months, and progressed with age. In addition, we found that ERK activation was induced by PKD2 overexpression via B-Raf signaling, providing a possible molecular mechanism of cystogenesis. In PKD2 transgenic mice, B-Raf/MEK/ERK sequential signaling was up-regulated. Additionally, the transgenic human polycystin-2 partially rescues the lethality of Pkd2 knock-out mice and therefore demonstrates that the transgene generated a functional product. Functional strengthening or deregulated activation of PKD2 may be a direct cause of ADPKD. The present study provides evidence for an in vivo role of overexpressed PKD2 in cyst formation. This transgenic mouse model should provide new insights into the pathogenic mechanism of human ADPKD.
authors.affiliation: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Park
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Sung
authors.forename: Moon Hee
authors.initials: MH
authors.lastname: Yang
authors.forename: Ji Yeun
authors.initials: JY
authors.lastname: Noh
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Lee
authors.forename: Yeon Joo
authors.initials: YJ
authors.lastname: Yook
authors.forename: Kyung Hyun
authors.initials: KH
authors.lastname: Yoo
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Roh
authors.forename: Ingyu
authors.initials: I
authors.lastname: Kim
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Hwang
authors.forename: Goo Taeg
authors.initials: GT
authors.lastname: Oh
authors.forename: Je Kyung
authors.initials: JK
authors.lastname: Seong
authors.forename: Curie
authors.initials: C
authors.lastname: Ahn
authors.forename: Han-Woong
authors.initials: HW
authors.lastname: Lee
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Park
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D049109:Cell Proliferation; D003560:Cysts / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D050396:TRPP Cation Channels / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D048493:Proto-Oncogene Proteins B-raf; D050396:TRPP Cation Channels; C482119:BRAF protein, human; C482120:Braf protein, mouse