The roles of connective tissue growth factor and integrin-linked kinase in high glucose-induced phenotypic alterations of podocytes.

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.

Dai HY ，Zheng M ，Lv LL ，Tang RN ，Ma KL ，Liu D ，Wu M ，Liu BC ... -  《-》

CTGF mediates high-glucose induced epithelial-mesenchymal transition through activation of β-catenin in podocytes.

Dai H ，Zhang Y ，Yuan L ，Wu J ，Ma L ，Shi H ... -  《-》

Protection of CTGF Antibody Against Diabetic Nephropathy in Mice Via Reducing Glomerular β-Catenin Expression and Podocyte Epithelial-Mesenchymal Transition.

Despite substantial progress in medical care, the morbidity rate of diabetic nephropathy (DN) remains high in patients with diabetes. Evidence suggests that connective tissue growth factor (CTGF) induced podocyte injury may contribute to DN and CTGF inhibition could reduce albuminuria. However, to date the mechanisms involved in the effect of CTGF on podocyte injury have not been fully understood. The aim of this study is to investigate the effects of therapeutic CTGF antibody on glomerular β-catenin expression and podocyte epithelial-mesenchymal transition (EMT) in diabetic mice. C57BL/6J mice were randomly divided into three groups as the following: the control, DN, and DN treated by CTGF antibody group. DN was induced by a single intraperitoneal injection of streptozotocin and then CTGF antibody was administrated three times per week for 8 weeks. Urinary albumin excretion, mesangial proliferation and matrix deposition, and β-catenin expression in glomeruli at mRNA and protein level were all increased in DN mice compared to that in the control. Besides, the development of EMT in podocytes from diabetic mice, demonstrated by the downregulation of nephrin and upregulation of desmin in glomeruli, was detected. Furthermore, blocking CTGF by specific antibody reduced albuminuria, prevented the overexpression of CTGF, as well as β-catenin, in glomeruli and subsequently ameliorated podocyte EMT in DN mice. In summary, this study suggested that CTGF antibody protected podocytes against injury in DN mice by reducing β-catenin overexpression and preventing podocyte EMT, which might provide new insight into the mechanism of CTGF inhibition in the treatment of DN. J. Cell. Biochem. 118: 3706-3712, 2017. © 2017 Wiley Periodicals, Inc.

Dai HY ，Ma LN ，Cao Y ，Chen XL ，Shi H ，Fan YP ，Yang B ... -  《-》

Differential involvement of the integrin-linked kinase (ILK) in RhoA-dependent rearrangement of F-actin fibers and induction of connective tissue growth factor (CTGF).

Graness A ，Giehl K ，Goppelt-Struebe M 《CELLULAR SIGNALLING》

High glucose and angiotensin II increase beta1 integrin and integrin-linked kinase synthesis in cultured mouse podocytes.

Han SY ，Kang YS ，Jee YH ，Han KH ，Cha DR ，Kang SW ，Han DS ... -  《CELL AND TISSUE RESEARCH》