title: Role of CD2-associated protein in albumin overload-induced apoptosis in podocytes.
abstract: Proteinuria is a well-established exacerbating factor of chronic kidney diseases. However, the harmful effects of protein overload on podocytes and the underlying mechanisms are still poorly understood. In the present study, we examined the effects of high concentrations of albumin on podocytes and investigated the role of CD2AP (CD2-associated protein) in albumin overload-induced podocyte apoptosis. Conditionally immortalized mouse podocytes were cultured in vitro and treated with different concentrations of BSA. In addition, CD2AP eukaryotic expression vector or siRNA (small interfering RNA) was transfected into podocytes before they were exposed to BSA. Podocyte apoptosis, expressions of active caspase-3 (p17) and CD2AP, and the distribution of F-actin cytoskeleton were detected by flow cytometry, Western-blot analysis and fluorescent staining respectively. It was found that exposure of podocytes to BSA induced podocyte apoptosis in a concentration-dependent manner that was accompanied by up-regulation of active caspase-3, the disruption of F-actin cytoskeleton, and decreased expression of CD2AP. Transfection of CD2AP eukaryotic expression vector into podocytes increased CD2AP expression, partially restored F-actin distribution, blocked active caspase-3 expression and inhibited podocyte apoptosis. In contrast, transfection of CD2AP siRNA deteriorated the above changes induced by BSA. It is concluded that protein overload induces podocyte apoptosis via the down-regulation of CD2AP and subsequent disruption of cytoskeleton of podocytes, and CD2AP may play an important role in protein overload-induced podocyte injury.
authors.affiliation: Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Peoples Republic of China.
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: He
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Shan
authors.initials: S
authors.lastname: Chen
authors.forename: Bing-Qing
authors.initials: BQ
authors.lastname: Deng
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Shao
authors.forename: Xiu-Juan
authors.initials: XJ
authors.lastname: Tian
authors.forename: Zhan
authors.initials: Z
authors.lastname: Fang
authors.forename: Xi-Feng
authors.initials: XF
authors.lastname: Sun
authors.forename: Jian-She
authors.initials: JS
authors.lastname: Liu
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Zhu
authors.forename: Xian-Fang
authors.initials: XF
authors.lastname: Meng
mesh_terms: D000199:Actins / Q000032:analysis / Q000187:drug effects; D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D053148:Caspase 3 / Q000096:biosynthesis / Q000235:genetics; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics; D003599:Cytoskeleton / Q000187:drug effects; D005434:Flow Cytometry; D007668:Kidney / Q000378:metabolism; D007674:Kidney Diseases; D051379:Mice; D050199:Podocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011507:Proteinuria / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D012710:Serum Albumin, Bovine / Q000378:metabolism / Q000494:pharmacology*; D015398:Signal Transduction
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C114545:CD2-associated protein; D003598:Cytoskeletal Proteins; D034741:RNA, Small Interfering; D012710:Serum Albumin, Bovine; D053148:Caspase 3