Angiopoietin-like protein 2 is specifically expressed in the renal tissues of diabetic nephropathy db/db mice / 医学研究生学报

ABSTRACT

Objective: ANGPTL2 is a newly found angiogenesis-associated protein.In the previous studies,we found that the renal expression of ANGPTL2 is involved in the development of diabetic nephropathy,but failed to reveal the exact distribution and synthesis of renal ANGPTL2.This study aimed to analyze the expression of the ANGPTL2 gene in the glomerulus and tubules in the kidney of db/db mice with diabetic nephropathy and to determine the cells responsible for the synthesis of renal ANGPTL2.Methods: Glomerulus and tubules were microdissected from the renal tissue of diabetic db/db mice and the expression of ANGPTL2 mRNA was analyzed by RT-PCR.The distribution and synthesis of ANGPTL2 in the kidney of the db/db mice were determined by immunohistochemistry,dual-labeling immunofluorescence and immunoelectron microscopy.Results: Significantly increased expression of ANGPTL2 mRNA was found in the glomeruli but not in the tubules of the diabetic db/db mice,as compared with the controls.Immunohistochemistry revealed that the ANGPTL2 protein was distributed in a podocyte-like pattern;dual-labeling immunofluorescence analysis showed colocalization of ANGPTL2 with WT1(Wilms' tumor 1,a marker of podocyte) staining,suggesting that renal ANGPTL2 was expressed specifically by podocytes,which was confirmed by immunoelectron microscopy.Conclusion: ANGPTL2 is specifically expressed by podocytes in diabetic nephropathy mice.