Cystogenesis in ARPKD results from increased apoptosis in collecting duct epithelial cells of Pkhd1 mutant kidneys |
| |
Authors: | Bo Hu Xiusheng He Ao Li Qingchao Qiu Cunxi Li Dan Liang Ping Zhao Jie Ma Robert J Coffey Qimin Zhan Guanqing Wu |
| |
Institution: | aCancer Research Institute, University of South China, Hengyang, Hunan, 421001, China;bDepartment of Medicine, Vanderbilt University, Nashville, TN 37232, USA;cDepartment of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA;dDivision of Translational Cancer Research and Therapy, State Key Laboratory of Molecular Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences, Beijing, 100021, China |
| |
Abstract: | Mutations in the PKHD1 gene result in autosomal recessive polycystic kidney disease (ARPKD) in humans. To determine the molecular mechanism of the cystogenesis in ARPKD, we recently generated a mouse model for ARPKD that carries a targeted mutation in the mouse orthologue of human PKHD1. The homozygous mutant mice display hepatorenal cysts whose phenotypes are similar to those of human ARPKD patients. By littermates of this mouse, we developed two immortalized renal collecting duct cell lines with Pkhd1 and two without. Under nonpermissive culture conditions, the Pkhd1−/− renal cells displayed aberrant cell–cell contacts and tubulomorphogenesis. The Pkhd1−/− cells also showed significantly reduced cell proliferation and elevated apoptosis. To validate this finding in vivo, we examined proliferation and apoptosis in the kidneys of Pkhd1−/− mice and their wildtype littermates. Using proliferation (PCNA and Histone-3) and apoptosis (TUNEL and caspase-3) markers, similar results were obtained in the Pkhd1−/− kidney tissues as in the cells. To identify the molecular basis of these findings, we analyzed the effect of Pkhd1 loss on multiple putative signaling regulators. We demonstrated that the loss of Pkhd1 disrupts multiple major phosphorylations of focal adhesion kinase (FAK), and these disruptions either inhibit the Ras/C-Raf pathways to suppress MEK/ERK activity and ultimately reduce cell proliferation, or suppress PDK1/AKT to upregulate Bax/caspase-9/caspase-3 and promote apoptosis. Our findings indicate that apoptosis may be a major player in the cyst formation in ARPKD, which may lead to new therapeutic strategies for human ARPKD. |
| |
Keywords: | Pkhd1 Fibrocystin ARPKD Apoptosis Proliferation |
本文献已被 ScienceDirect 等数据库收录! |
|