title: TGF-β1 stimulates movement of renal proximal tubular epithelial cells in a three-dimensional cell culture via an autocrine TGF-β2 production.
abstract: TGF-βs are multifunctional cytokines, but their roles in human renal homeostasis are not fully understood. This study investigated the role of TGF-β1 in the movement of human renal proximal tubular epithelial cells (PTECs) in a three-dimensional (3D) model. HKC-8 cells, a human PTEC line, were grown in a 3D collagen culture system. Cell movement was observed under a microscope. The gene expression was examined using PCR Arrays or qRT-PCR, and protein levels by Western blot. Here, we showed that the tight junction structure formed between adjacent cells of a HKC-8 cell colony in 3D cultures, and TGF-β1 stimulated their movement, evidenced by the appearance of fingerlike pseudopodia in the leader cells at the edge of the colonies. The cell movement of these human PTECs was correlated with up-regulation of both MMP2 and MMP9 and down-regulation or inactivation of PLAUR and PTK2B. Analysis of TGF-β signaling targets confirmed autocrine production of TGF-β2 and its cleaving enzyme furin as well as SNAI1 by TGF-β1stimulation. Knockdown of TGF-β2 expression disrupted TGF-β1-stimulated PTEC invasiveness, which was correlated with the down-regulation of MMP2 and MMP9. In conclusion, the activation of TGF-β receptor autocrine signaling by up-regulated TGF-β2 may play a pivotal role in TGF-β1-induced human PTEC movement, which could be mediated at least by both MMP2 and MMP9.
authors.affiliation: Department of Urology, West China School of Medicine, Sichuan University, Chengdu, China; Department of Urologic Sciences, The University of British Columbia, Vancouver, British Columbia, Canada; Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada. Electronic address: luodeyi1985@163.com.
authors.forename: Deyi
authors.initials: D
authors.lastname: Luo
authors.affiliation: Department of Urologic Sciences, The University of British Columbia, Vancouver, British Columbia, Canada; Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada. Electronic address: Qiunong@hotmail.com.
authors.forename: Qiunong
authors.initials: Q
authors.lastname: Guan
authors.affiliation: Department of Urology, West China School of Medicine, Sichuan University, Chengdu, China. Electronic address: wangkj@scu.edu.cn.
authors.forename: Kunjie
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Urologic Sciences, The University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: Chris.nguan@ubcurology.com.
authors.forename: Christopher Y C
authors.initials: CYC
authors.lastname: Nguan
authors.affiliation: Department of Urologic Sciences, The University of British Columbia, Vancouver, British Columbia, Canada; Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada. Electronic address: caigan@mail.ubc.ca.
authors.forename: Caigan
authors.initials: C
authors.lastname: Du
mesh_terms: D019898:Autocrine Communication; D018929:Cell Culture Techniques; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D019108:Tight Junctions / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D003094:Collagen
keywords: 3D culture; Cell migration; Kidney; Signaling transduction; TGF-β; Tubular epithelial cells