SUN-003 MECHANISM OF SELECTIVE ALBUMINURIA IN MINIMAL CHANGE NEPHROTIC SYNDROME

Abstract

Water and electrolytes are filtered through slit membranes, however in minimal change nephrotic syndrome with foot process effacement it is not well understood whether albumin molecules will be filtered through the slit membrane. We reported that albumin endocytosis by FcRn was enhanced in the podocyte of puromycin aminonucleoside (PAN)-induced minimal change nephrotic syndrome rat, and treatment with anti-FcRn antibody decreased albumin endocytosis and urinary protein (Kidney Int 2011). Minimal change nephrotic syndrome model was induced by puromycin amino nucleoside, and podocytes were observed by electron microscope and low vacuum scanning electron microscope. Electron microscopy demonstrated many vesicles were observed in the podocytes of PAN rat with 3D observation. SDS-polyacrylamide electrophoresis of glomerular proteins isolated from PAN rats showed that several protein bands were increased than those from control rats, and those increased protein bands were identified as dynein -1, myosin 7 and myosin 9 by mass spectrometry. These motor molecules are capable of transporting vesicles containing albumin in the podocytes of PAN nephrotic rat. In renal biopsy, electron microscopic examination of human minimal change disease cases showed numerous vesicles and microtubules in podocytes, and a number of exocytotic holes were found on the surface of podocytes by low vacuum scanning electron microscopy. In conclusion, podocyte vesicle transport could play an important role in the selective albuminuria in the minimal change nephrotic syndrome.