Cyst formation in kidney via B-Raf signaling in the PKD2 transgenic mice.
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.
Park
Eun Young
EY
Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Republic of Korea.
Sung
Young Hoon
YH
Yang
Moon Hee
MH
Noh
Ji Yeun
JY
Park
So Young
SY
Lee
Tae Young
TY
Yook
Yeon Joo
YJ
Yoo
Kyung Hyun
KH
Roh
Kyung Jin
KJ
Kim
Ingyu
I
Hwang
Young-Hwan
YH
Oh
Goo Taeg
GT
Seong
Je Kyung
JK
Ahn
Curie
C
Lee
Han-Woong
HW
Park
Jong Hoon
JH
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
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