-
Zhen Zhang,
Bao-Ying Li,
Xiao-Li Li,
Mei Cheng,
Fei Yu,
Wei-da Lu, Qian Cai,
Jun-Fu Wang,
Rui-Hai Zhou,
Hai-Qing Gao,
Lin Shen
[show abstract]
[hide abstract]
ABSTRACT: Diabetic nephropathy, as a severe microvascular complication of diabetic mellitus, has become the leading cause of end-stage renal diseases. However, none 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.
Biochimica et Biophysica Acta 03/2013; · 4.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Patients with diabetes often develop hypertension and atherosclerosis leading to cardiovascular disease. However, some diabetic patients develop heart failure without hypertension and coronary artery disease, a process termed diabetic cardiomyopathy. Phlorizin has been reported to be effective as an antioxidant in treating diabetes mellitus, but little is known about its cardioprotective effects on diabetic cardiomyopathy. In this study, we investigated the role of phlorizin in preventing diabetic cardiomyopathy in db/db mice. We found that phlorizin significantly decreased body weight gain and the levels of serum fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TC), and advanced glycation end products (AGEs). Morphologic observations showed that normal myocardial structure was better preserved after phlorizin treatment. Using isobaric tag for relative and absolute quantitation (iTRAQ) proteomics, we identified differentially expressed proteins involved in cardiac lipid metabolism, mitochondrial function, and cardiomyopathy, suggesting that phlorizin may prevent the development of diabetic cardiomyopathy by regulating the expression of key proteins in these processes. We used ingenuity pathway analysis (IPA) to generate an interaction network to map the pathways containing these proteins. Our findings provide important information about the mechanism of diabetic cardiomyopathy and also suggest that phlorizin may be a novel therapeutic approach for the treatment of diabetic cardiomyopathy.
Journal of diabetes research. 01/2013; 2013:263845.
-
Shi-Yang Zhang,
Bao-Ying Li,
Xiao-Li Li,
Mei Cheng, Qian Cai,
Fei Yu,
Wei-Dong Wang,
Min Tan,
Guang Yan,
Shi-Lian Hu,
Hai-Qing Gao
[show abstract]
[hide abstract]
ABSTRACT: Diabetic retinopathy (DR) is a leading cause of vision loss in working-age people. To retard the development and progression of retina lesions, effective therapeutic strategies directed toward key molecular targets are desired. Phlorizin is effective in treating diabetic complications, but little is known about functional protein changes that may mediate its actions. The aim of this study was to identify retinal proteomic alterations in db/db mice treated with phlorizin.
We used C57BLKS/J db/db mice as a type 2 diabetic animal model, while C57BLKS/J db/m mice were selected as the control. Phlorizin (20 mg/kg bodyweight /d) was administrated to db/db mice for ten weeks. Serum fasting blood glucose and advanced glycation end products were determined. Meanwhile, retina cell apoptosis was determined with terminal transferase dUTP nick end labeling. Isobaric tags for relative and absolute quantification and subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to identify and profile retinal proteins among control, untreated diabetic, and phlorizin-treated db/db mice. The expression of glial fibrillary acidic protein was measured in retinas using western blotting analysis.
Phlorizin treatment significantly reduced fasting blood glucose and levels of advanced glycation end products (p<0.05) and remarkably inhibited retina cell apoptosis and the expression of glial fibrillary acidic protein in the retinas of db/db mice. In addition, we identified 1,636 proteins from retina tissue in total, of which 348 proteins were differentially expressed in db/db mice compared with the controls. Only 60 proteins in the retinas of the db/db mice were found to be differentially changed following phlorizin treatment, including 33 proteins that were downregulated and 27 proteins that were upregulated. Most of these differentially changed proteins were involved in oxidative stress, apoptosis, energy metabolism, and signaling transduction.
Our study revealed the expression of proteins differentially changed after phlorizin therapy. These proteins are most likely to participate in the development and recovery of DR. Our findings help expand understanding of the mechanism underlying the onset and progression of DR, and provide novel targets for evaluating the effects of phlorizin therapy.
Molecular vision 01/2013; 19:812-821. · 2.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although phlorizin has been used in the treatment of diabetes mellitus for over 100 years, the underlying molecular mechanisms have not been fully elucidated. This study investigated the effect of phlorizin on body weight, blood glucose, blood triglycerides (TG), blood total cholesterol (TC), as well as overall changes in protein expression in db/db diabetic mouse liver. Phlorizin significantly decreased body weight gain and the levels of glucose, TC and TG in blood. Isobaric tag for relative and absolute quantitation (iTRAQ) quantitative proteomics profiling revealed that phlorizin interfered with the processes of carbohydrate metabolism, fatty acid biosynthesis and β-oxidation, cholesterol biosynthesis, and free radical scavenging by affecting the expression of key proteins in these processes. Ingenuity Pathway Analysis successfully established several pathway networks, in which many differentially expressed proteins were involved. The differential expression of several proteins was validated by western blotting. Our study offers important information on the mechanism of phlorizin treatment in diabetes mellitus, particularly in the liver.
Molecular Medicine Reports 02/2012; 5(5):1285-94. · 0.42 Impact Factor
-
Fei Yu,
Bao-Ying Li,
Xiao-Li Li, Qian Cai,
Zhen Zhang,
Mei Cheng,
Mei Yin,
Jun-Fu Wang,
Jian-Hua Zhang,
Wei-da Lu,
Rui-Hai Zhou,
Hai-Qing Gao
[show abstract]
[hide abstract]
ABSTRACT: Atherosclerosis is one of the major complications of type 2 diabetic patients (T2DM), leading to morbidity and mortality. Grape seed procyanidin B2 (GSPB2) has demonstrated protective effect against atherosclerosis, which is believed to be, at least in part, a result of its antioxidative effects. The aim of this study is to identify the target protein of GSPB2 responsible for the protective effect against atherosclerosis in patients with DM.
GSPB2 (30 mg/kg body weight/day) were administrated to db/db mice for 10 weeks. Proteomics of the aorta extracts by iTRAQ analysis was obtained from db/db mice. The results showed that expression of 557 proteins were either up- or down-regulated in the aorta of diabetic mice. Among those proteins, 139 proteins were normalized by GSPB2 to the levels comparable to those in control mice. Among the proteins regulated by GSPB2, the milk fat globule epidermal growth factor-8 (MFG-E8) was found to be increased in serum level in T2DM patients; the serum level of MFG-E8 was positively correlated with carotid-femoral pulse wave velocity (CF-PWV). Inhibition of MFG-E8 by RNA interference significantly suppressed whereas exogenous recombinant MFG-E8 administration exacerbated atherogenesis the db/db mice. To gain more insights into the mechanism of action of MFG-E8, we investigated the effects of MFG-E8 on the signal pathway involving the extracellular signal-regulated kinase (ERK) and monocyte chemoattractant protein-1 (MCP-1). Treatment with recombinant MFG-E8 led to increased whereas inhibition of MFG-E8 to decreased expression of MCP-1 and phosphorylation of ERK1/2.
Our data suggests that MFG-E8 plays an important role in atherogenesis in diabetes through both ERK and MCP-1 signaling pathways. GSPB2, a well-studied antioxidant, significantly inhibited the arterial wall changes favoring atherogenesis in db/db mice by down-regulating MFG-E8 expression in aorta and its serum level. Measuring MFG-E8 serum level could be a useful clinical surrogate prognosticating atherogenesis in DM patients.
PLoS ONE 01/2012; 7(12):e52541. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Advanced glycation end product (AGE)-induced vascular smooth muscle cell (VSMC) proliferation is vital to the progression of diabetic vasculopathy. A grape seed procyanidin extract has been reported to possess anti-oxidative and anti-inflammatory properties and to display a significant cardiovascular protective effect, but little is know about the underlying mechanism. The objective of this present study was to determine whether GSPB2 (grape seed procyanidin B2), which is a dimeric procyanidin and more biologically active, could inhibit AGE-induced VSMC proliferation by affecting the production of ubiquitin COOH-terminal hydrolase 1 (UCH-L1), the degradation of IκB-α and nuclear translocation of NF-κB in human aortic smooth muscle cells (HASMCs). Our data show that GSPB2 preincubation markedly inhibited AGE-induced proliferation and migration of HASMCs in a dose-dependent manner and upregulated the protein level of UCH-L1. Further studies revealed that the GSPB2 pretreatment markedly attenuated the degradation of IκB-α and nuclear translocation of NF-κB by modulating ubiquitination of IκB-α in AGE-exposed HASMCs. These results collectively suggest that AGE-induced HASMC proliferation and migration was suppressed by GSPB2 through regulating UCH-L1 and ubiquitination of IκB-α. GSPB2 may therefore have therapeutic potential in preventing and treating vascular complications of diabetes mellitus.
Bioscience Biotechnology and Biochemistry 09/2011; 75(9):1692-7. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: One of characteristics of diabetes mellitus (DM) is endothelial cell (EC) dysfunction and apoptosis which contributes to the development of vasculopathy. Advanced glycation end products (AGEs) continuously produced in the setting of DM play an important role in causing EC dysfunction and apoptosis. However, the underlying molecular mechanism remains largely elusive. Lactadherin, a secreted glycoprotein of milk-fat globule, is expressed by multiple cell types of arterial wall including ECs. Our previous proteomic studies showed that the expression of lactadherin was significantly increased in the aorta of diabetic rats as compared with control rats and treatment with grape seed procyanidin extracts significantly inhibited the lactadherin expression in diabetic rats. We hypothesized that lactadherin plays a critical role in AGEs-induced EC apoptosis; grape seed procyanidin B2 (GSPB2) and resveratrol protect against AGEs-induced EC apoptosis through lactadherin regulation. Our results showed that AGEs upregulated lactadherin expression and lactadherin RNA interference significantly attenuated AGEs-induced EC apoptosis. Overexpression of lactadherin increased EC apoptosis with up-regulation of Bax/Bcl-2 ratio, cytochrome c release, caspase-9 and caspase-3 activation suggesting the involvement of mitochondria apoptosis pathway. Mechanistically, overexpression of lactadherin reduced the phosphorylation of GSK3beta at baseline. Our study also revealed nine proteins interacting with lactadherin in HUVEC and study of these candidate proteins could unveil further underlying molecular mechanisms. In summary, our study identified lactadherin as a key player responsible for AGEs-induced EC apoptosis and antioxidants GSPB2 and resveratrol protect against AGEs-induced EC apoptosis by inhibiting lactadherin. Targeting lactadherin with antioxidant could be translated into clinical application in the fighting against DM complications.
Apoptosis 07/2011; 16(7):732-45. · 4.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the effects of GSPB2 (grape seed procyanidin B2) on the apoptosis of HUVECs (human umbilical endothelial cells) induced by AGEs (advanced glycation end products), HUVECs were treated with AGEs (200 μg/ml) in the presence or absence of GSPB2 (2.5, 5.0 and 10.0 μmol/l). Our findings showed that (i) AGEs induced HUVEC apoptosis and up-regulated the expression of caspase-3 activation and lactadherin and reduced the phosphorylation of GSK3β (glycogen synthase kinase 3β) at baseline. (ii) Treatment of HUVEC with GSPB2 significantly inhibited the cell apoptosis and the expression of caspase-3 activation and lactadherin induced by AGEs. Moreover, GSPB2 inhibited intracellular reactive oxygen species in a dose-dependent manner in AGEs-treated cells as determined by flow cytometry. (iii) GSPB2 increased the phosphorylation of GSK3β of HUVEC in response to AGEs. These findings suggest that the signalling pathway involving phosphorylation of GSK3β and lactadherin might play a key role in the endothelial apoptosis. GSPB2 therapy could become an effective approach to battling AGEs-induced endothelial apoptosis.
Cell Biology International 01/2011; 35(7):663-9. · 1.48 Impact Factor
