Different distribution and expression of mammalian target of rapamycin complex in the kidney of diabetic nephropathy mice

doi:10.3969/j.issn.0529-1356.2014.04.021

Abstract

Abstract:

Objective To investigate the different distribution and expression of mammalian target of rapamycin complex (mTORC) in the kidney of diabetic nephropathy (DN) mice. Methods Fourteen eight-week-old male C57BL/6 mice were assigned to 2 groups: the control group (n=7) and the streptozotocin (STZ)-induced DN group (n=7). Blood and urinary variables including glucose, albumin, creatinine and albumin/creatinine ratio were assessed 2 weeks after STZ injection. Hematoxylin-eosin staining was performed for renal pathological analyses. The distributions of mTOR, phosph-ser2448-mTOR(p-mTOR), mTORC1(Raptor), mTORC2(Rictor) and phosph-ser240/244-S6K1 (p-S6K1) were determined by immunofluorescence. The expression levels of mTOR, p-mTOR, mTORC1(Raptor), mTORC2(Rictor), S6K1 and p-S6K1 were detected by Western blotting. Results Two weeks after STZ injection, the diabetic mice developed albuminuria (P<0.01) and renal hypertrophy (P<0.05). The immunofluorescence positive staining for mTOR, Raptor, and Rictor was distributed in the epithelial cells of proximal tubules, glomerular mesangium and capillary loops as well as the medullary collecting ducts of the control mouse kidney. These positive signals increased in the DN mouse kidney (P<0.05). However, pS6K1 was not detected in the inner medulla of control mouse and p-mTOR was not found in the glomeruli of both control and DN mice. Conclusion mTORC is widely expessed in the mouse kidney and participates in the development of DN, whereas the 2448 serine phosphorylation of mTOR may be not implicated in the hyperglycemia mediated glomerular injury.

Key words: Mammaliam target of rapamycin, Diabetic nephropathy, Rictor, Raptor, Immunofluorescence, Western blotting, Mouse

ZHAO Hong JI Qian-qian LI Yong-xia DUAN Qiu-hong YAO Li-jun*. Different distribution and expression of mammalian target of rapamycin complex in the kidney of diabetic nephropathy mice[J]. AAS, 2014, 45(4): 555-560.

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