Proteomic analysis of kidney and protective effects of grape seed procyanidin B2 in db/db mice indicate MFG-E8 as a key molecule in the development of diabetic nephropathy

Abstract

Diabetic nephropathy, as a severe microvascular complication of diabetic mellitus, has become the leading cause of end-stage renal diseases. However, no effective therapeutic strategy has been developed to prevent renal damage progression to end stage renal disease. Hence, the present study evaluated the protective effects of grape seed procyanidin B2 (GSPB2) and explored its molecular targets underlying diabetic nephropathy by a comprehensive quantitative proteomic analysis in db/db mice. Here, we found that oral administration of GSPB2 significantly attenuated the renal dysfunction and pathological changes in db/db mice. Proteome analysis by isobaric tags for relative and absolute quantification (iTRAQ) identified 53 down-regulated and 60 up-regulated proteins after treatment with GSPB2 in db/db mice. Western blot analysis confirmed that milk fat globule EGF-8 (MFG-E8) was significantly up-regulated in diabetic kidney. MFG-E8 silencing by transfection of MFG-E8 shRNA improved renal histological lesions by inhibiting phosphorylation of extracellular signal-regulated kinase1/2 (ERK1⁄2), Akt and glycogen synthase kinase-3beta (GSK-3β) in kidneys of db/db mice. In contrast, over-expression of MFG-E8 by injection of recombinant MFG-E8 resulted in the opposite effects. GSPB2 treatment significantly decreased protein levels of MFG-E8, phospho-ERK1/2, phospho-Akt, and phospho-GSK-3β in the kidneys of db/db mice. These findings yield insights into the pathogenesis of diabetic nephropathy, revealing MFG-E8 as a new therapeutic target and indicating GSPB2 as a prospective therapy by down-regulation of MFG-E8, along with ERK1/2, Akt and GSK-3β signaling pathway.

System-Level and Granger Network Analysis of Integrated Proteomic and Metabolomic Dynamics Identifies Key Points of Grape Berry Development at the Interface of Primary and Secondary Metabolism

“…These secondary metabolites, especially flavonoids, play multiple roles in grape and attract more and more attentions due to their health benefits (Anastasiadi et al, 2010; Kim et al, 2013; Zhang et al, 2013). During grape berry development, the detected flavonoids presented two distinct changing patterns (Figure 2E).…”

“…Grape berries are consumed either as fresh fruit or processed to raisins, juice and wine. Besides its enormous economical and nutritional values, grapes and grape products possess a wide variety of health benefits, such as antioxidation (Sánchez-Moreno et al, 1999; Doshi et al, 2006; Sánchez-Alonso et al, 2007; Sáyago-Ayerdi et al, 2009; Anastasiadi et al, 2010), cardiovascular protection (Tebib et al, 1994; Adisakwattana et al, 2010; Razavi et al, 2013), neuroprotection (Feng et al, 2007), anti-obesity (Kim et al, 2013; Zhang et al, 2013), etc.…”

Ursodeoxycholic acid and 4-phenylbutyrate prevent endoplasmic reticulum stress-induced podocyte apoptosis in diabetic nephropathy

“…Thus, this model has been used in a number of studies for the research of DN. [34][35][36] In this study, elevated levels of albuminuria and exacerbated histological alterations indicate damage in kidneys of diabetic db/db mice. Interestingly, UDCA or 4-PBA treatment could restore renal dysfunction and mesangial expansion in db/db mice, suggesting that both treatments effectively prevented the progression of DN.…”

“…Progressive expansion of the mesangial matrix is a key histological appearance of DN. 34 The db/db murine model of type 2 diabetes could develop renal dysfunction closely similar to that of humans. Thus, this model has been used in a number of studies for the research of DN.…”

Effects of grape seed extract on oxidative stress and antioxidant defensemarkers in streptozotocin-induced diabetic rats

“…Various studies (29)(30)(31)(32)(33)(34) have shown that clinical and experimental diabetes are associated with increased formation of free radicals and with decreases in antioxidant potential. In the present study, plasma XO activity significantly increased in diabetic rats.…”