title: The roles of connective tissue growth factor and integrin-linked kinase in high glucose-induced phenotypic alterations of podocytes.
abstract: Emerging evidence has suggested that podocytes undergo epithelial-mesenchymal transition (EMT) in diabetic nephropathy (DN). Connective tissue growth factor (CTGF) and integrin-linked kinase (ILK) are involved in the progression of DN. However, the underlying mechanisms of EMT are not well understood. The study aimed to investigate the roles of CTGF and ILK in high glucose-induced phenotypic alterations of podocytes and determine whether ILK signaling is downstream of CTGF. The epithelial marker of nephrin and the mesenchymal marker of desmin were investigated by real-time RT-PCR and Western blotting. The results demonstrated that podocytes displayed a spreading, arborized morphology in normal glucose, whereas they had a cobblestone morphology in high glucose conditions, accompanied by decreased nephrin expression and increased desmin expression, suggesting podocytes underwent EMT. In response to high glucose, CTGF and ILK expression in podocytes were increased in a dose- and time-dependent manner, whereas the increase did not occur in the osmotic control. Furthermore, the inhibition of CTGF with anti-CTGF antibody prevented the phenotypic transition, as demonstrated by the preservation of epithelial morphology, the suppression of high glucose-induced desmin overexpression and the restoration of nephrin. Of note, the upregulation of ILK induced by high glucose was partially blocked by the inhibition of CTGF. In summary, these findings suggested that CTGF and ILK were involved in high glucose-induced phenotypic alterations of podocytes. ILK acted as a downstream kinase of CTGF and high glucose-induced ILK expression might occur through CTGF-dependent and -independent pathways.
authors.affiliation: Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, Nanjing 210009, China.
authors.forename: Hou-Yong
authors.initials: HY
authors.lastname: Dai
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.forename: Lin-Li
authors.initials: LL
authors.lastname: Lv
authors.forename: Ri-Ning
authors.initials: RN
authors.lastname: Tang
authors.forename: Kun-Ling
authors.initials: KL
authors.lastname: Ma
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.forename: Bi-Cheng
authors.initials: BC
authors.lastname: Liu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002460:Cell Line; D055513:Connective Tissue Growth Factor / Q000276:immunology / Q000378:metabolism*; D003893:Desmin / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000473:pathology*; D058750:Epithelial-Mesenchymal Transition; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D050199:Podocytes / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D000099200:Scaffold Protein ILK
chemical_list: D000911:Antibodies, Monoclonal; D055513:Connective Tissue Growth Factor; D003893:Desmin; D005947:Glucose; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK; C113267:nephrin