title: Glycogen synthase kinase‑3β is required for epithelial‑mesenchymal transition and barrier dysfunction in mouse podocytes under high glucose conditions.
abstract: Epithelial-mesenchymal transition (EMT) is important for diabetic nephropathy (DN). Podocytes are specialized epithelial cells, which form a major component of the glomerular filtration barrier. Podocyte damage has been suggested to be the primary mechanism behind the albuminuria associated with DN. The present study aimed to determine the function of glycogen synthase kinase (GSK)‑3β in EMT and barrier dysfunction of mouse podocytes exposed to high glucose (HG) conditions. Matured and differentiated podocytes were treated with normal glucose (NG), HG or NG + mannitol. Podocytes were also transfected with a small interfering RNA (siRNA) against GSK‑3β or a scrambled siRNA, or were treated with lithium chloride (LiCl), a GSK‑3β inhibitor, under NG or HG conditions. The expression levels of the epithelial cell markers, nephrin and podocin, and the myofibroblast cell markers, α‑smooth muscle actin (SMA) and fibronectin, in podocytes by western blot analysis and immunofluorescence staining, respectively. The monolayer barrier function was assessed by albumin inflow. The phosphorylation and activity levels of GSK‑3β were also quantified. It was observed that HG promotes EMT in podocytes, due to the increased levels of podocin and nephrin expression and the reduced α‑SMA and fibronectin expression levels. HG also induced barrier dysfunction and increased the expression level of total GSK‑3β, Try216‑phosphorylated‑GSK‑3β and the GSK‑3β activity in podocytes. Transfection of GSK‑3β siRNA or treatment with LiCl reversed the HG‑induced EMT and barrier dysfunction in podocytes. In conclusion, the present study determined that GSK‑3β is required for EMT and barrier dysfunction in podocytes under HG conditions; therefore, GSK‑3β may be a novel target for the treatment of DN.
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
authors.forename: Lili
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
authors.forename: Yingjin
authors.initials: Y
authors.lastname: Qiao
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
authors.forename: Zhangsuo
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000199:Actins / Q000096:biosynthesis; D000818:Animals; D003928:Diabetic Nephropathies / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D060730:Glomerular Filtration Barrier / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000633:toxicity; D000071679:Glycogen Synthase Kinase 3 beta / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis; D018021:Lithium Chloride / Q000008:administration & dosage; D008565:Membrane Proteins / Q000096:biosynthesis; D051379:Mice; D050199:Podocytes / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering
chemical_list: D000199:Actins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; D034741:RNA, Small Interfering; C544013:alpha-smooth muscle actin, mouse; C113267:nephrin; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D018021:Lithium Chloride; D005947:Glucose