1. Overexpression of Interleukin-13 Induces Minimal-Change–Like Nephropathy in Rats
- Author
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Changli Wei, Kin-Wai Lai, Caroline G.L. Lee, Puay-Hoon Tan, Yap Hk, Stanley C. Jordan, Li Kiang Tan, and Gilbert S.C. Chiang
- Subjects
medicine.medical_specialty ,Podocyte foot ,Kidney ,urologic and male genital diseases ,Podocyte ,Nephropathy ,Animals, Genetically Modified ,Nephrin ,Internal medicine ,medicine ,Dystroglycan ,Animals ,Rats, Wistar ,Dystroglycans ,Interleukin-13 ,biology ,urogenital system ,Nephrosis, Lipoid ,Intracellular Signaling Peptides and Proteins ,Interleukin-4 Receptor alpha Subunit ,Membrane Proteins ,General Medicine ,medicine.disease ,female genital diseases and pregnancy complications ,Rats ,Electroporation ,Endocrinology ,medicine.anatomical_structure ,Gene Expression Regulation ,Nephrology ,B7-1 Antigen ,Interleukin-13 Receptor alpha2 Subunit ,biology.protein ,Albuminuria ,Podocin ,Female ,medicine.symptom ,Nephrotic syndrome - Abstract
IL-13 has been implicated in the pathogenesis of minimal-change nephrotic syndrome. This study aimed to investigate the role of IL-13 on the development of proteinuria and expression of podocyte-related genes that are associated with nephrotic syndrome. IL-13 was overexpressed in Wistar rats through transfection of a mammalian expression vector cloned with the rat IL-13 gene, into the quadriceps by in vivo electroporation. Serum IL-13, albumin, cholesterol, and creatinine and urine albumin were measured serially. Kidneys were harvested after day 70 for histology and electron microscopy. Glomerular gene expression of nephrin, podocin, dystroglycan, B7-1, and IL-13 receptor subunits were examined using real-time PCR with hybridization probes and expressed as an index against beta-actin. Protein expression of these molecules was determined by immunofluorescence staining. The IL-13-transfected rats (n = 41) showed significant albuminuria, hypoalbuminemia, and hypercholesterolemia when compared with control rats (n = 17). No significant histologic changes were seen in glomeruli of IL-13-transfected rats. However, electron microscopy showed up to 80% of podocyte foot process fusion. Glomerular gene expression was significantly upregulated for B7-1, IL-4Ralpha, and IL-13Ralpha2 but downregulated for nephrin, podocin, and dystroglycan. Immunofluorescence staining intensity was reduced for nephrin, podocin, and dystroglycan but increased for B7-1 and IL-4Ralpha in IL-13-transfected rats compared with controls. In conclusion, these results suggest that IL-13 overexpression in the rat could lead to podocyte injury with downregulation of nephrin, podocin, and dystroglycan and a concurrent upregulation of B7-1 in the glomeruli, inducing a minimal change-like nephropathy that is characterized by increased proteinuria, hypoalbuminemia, hypercholesterolemia, and fusion of podocyte foot processes.
- Published
- 2007