Purple Sweet Potato Color Attenuates Kidney Damage by Blocking VEGFR2/ROS/NLRP3 Signaling in High-Fat Diet-Treated Mice.

Our preliminary data showed that VEGFR2 upregulation promoted renal ROS overproduction in high-fat diet- (HFD-) treated mice. Given that ROS-induced NLRP3 activation plays a central role in the pathogenesis of type 2 diabetic kidney injury, we evaluate whether VEGFR2 upregulation induces type 2 diabetic kidney injury via ROS-mediated NLRP3 activation and further explore the underlying mechanism. Our results showed that VEGFR2 knockdown decreased ROS overproduction, blocked NLRP3-dependent inflammation, and alleviated kidney damage in HFD-treated mice. Treatment with α-lipoic acid, a scavenger of ROS, lowered ROS overproduction and alleviated NLRP3-triggered kidney injury of HFD-treated mice. Collectively, the VEGFR2/ROS/NLRP3 signal is a critical therapeutic strategy for the kidney injury of HFD-treated mice. Purple sweet potato color (PSPC), a natural anthocyanin, can exert renal protection by inhibiting ROS in HFD-treated mice. Here, we provide a novel mechanism of PSPC against renal damage in HFD-treated mice by downregulating VEGFR2 expression.

[Effects of Kaempferol on activation, proliferation and cell cycle of mouse T lymphocytes in vitro.].

AIM: To study the effects of Kaempferol on activation, proliferation and cell cycle of murine T lymphocytes, and to elucidate the mechanism of the immunosuppressive effect of Kaempferol. METHODS: Lymphocytes were prepared from lymphoid nodes of mouse, and were stimulated with polyclonal activators ConA, and then were co-cultured with Kaempferol of different final concentration. The effect on the expression of CD69 (the early marker of the activated T cells) on T lymphocytes were measured by flow cytometry combined with two colored monoclonal antibodies flow cytometry. While, the effect of Kaempferol on the proliferation of T lymphocytes in response to ConA stimulation was determined by MTT, cell cycle was detected by PI staining. RESULTS: Kaempferol (final concentration is 10, 20 and 40 mumol/L) can inhibit the expression of CD69 on activated T lymphocytes in a dose-dependent manner (P<0.05). The expression rate of CD69 on T cells in response to ConA was (39.11+/-1.17)%. After treatment with Kaempferol, the expression rate of CD69 reduced to (30.64+/-0.23)%, (27.95+/-0.04)% and (5.63+/-0.37)%, respectively (P< 0.05); The result of MTT showed that Kaempferol can inhibit the proliferation of T lymphocytes stimulated by ConA in a dose-dependent manner (P<0.05); The result of PI staining showed that Kaempferol can arrest cell cycle at S phage and G2/M at all experimental concentration (P<0.05). CONCLUSION: Kaempferol can effectively inhibit the activation, proliferation of mouse T lymphocytes in respond to ConA, arrest cell cycle at S phage and G2/M in vitro.

Anti-inflammatory and immunosuppressive effect of phloretin.

This study investigated the effect of phloretin (Ph) on the proliferation, activation, and cell-cycle distribution of mouse T lymphocytes and NO production and phagocytosis of macrophages. Carboxyfluorescein diacetatesuccinimidyl ester (CFDA-SE) staining plus flow cytometry assay was employed to obtain the proliferation-related index (PI) of lymphocytes. The expression levels of CD69 and CD25 on T lymphocytes stimulated with Con A were evaluated with flow cytometry after staining with fluorescent monoclonal antibody. Cell-cycle distribution of T lymphocytes was analyzed by propidium iodide staining. Griess kit was used to evaluate the NO production and fluorescent microbeads were used to analyze the phagocytosis ability of macrophages. Our results showed that phloretin (40, 60, and 80 micromol x L(-7)) significantly inhibited the proliferation of T lymphocytes and the PI reduced from 1.41 +/- 0.13 to 1.34 +/- 0.16, 1.19 +/- 0.12 and 1.07 +/- 0.06, respectively. Phloretin significantly inhibited the expression of CD69 and CD25 (P < 0.01). The cell cycle distribution analysis showed that phloretin could induce a cell cycle arrest at G0/G1 phase. NO production of LPS +IFN-gamma group of macrophages was (26.72 +/- 3.57) micromol x L(-1), and was significantly reduced by phloretin (P < 0.01). And phagocytosis rate of macrophages was significantly reduced by phloretin (P < 0.01). The results demonstrate that phloretin might be developed into a new immuosuppressive drug.

Increased connective tissue growth factor expression in a rat model of chronic heart allograft rejection.

BACKGROUND/PURPOSE: Chronic rejection limits the long-term success of cardiac transplantation and the underlying cause of the disease is unknown. Connective tissue growth factor (CTGF) is considered as a mitogenic and chemotactic factor for fibroblasts, and is associated with cell proliferation and collagen synthesis. We evaluated the expression of CTGF in a rat model of heart allograft chronic rejection. METHODS: Intra-abdominal heterotopic heart transplantation was performed from 20 Wistar rats to 20 Sprague-Dawley (SD) rats that received cyclosporine, mycophenolate mofetil and methylprednisolone as immunosuppression. Ten heart allografts were explanted at 2 and 8 weeks postoperatively for analysis of morphologic changes. The hearts from 10 normal Wistar rats served as a control group. Coronary artery density, luminal loss of myocardial coronary arteries, and myocardial fibrosis were measured. The expression of CTGF was studied by immunohistochemistry. Correlation between CTGF expression and development of cardiac allograft vasculopathy (CAV) or fibrosis was studied. RESULTS: Allografts harvested at 8 weeks postoperatively showed more coronary intimal proliferation, fibrosis and CTGF expression compared with the 2-week allografts (p < 0.05) and the controls (p < 0.01), but the coronary artery density was lower than in the control group (p < 0.05). However, the control group showed negligible CTGF expression. There were strong negative correlations between the gray value of CTGF protein expression and cardiac fibrosis and coronary intimal occlusion (r = -0.734, -0.713; p < 0.01), which demonstrated that CTGF protein expression was positively correlated with cardiac fibrosis and coronary intimal occlusion. CONCLUSION: CTGF is expressed in cardiomyocytes in CAV. Increased expression of CTGF in cardiac allografts is associated with development of CAV and fibrosis formation.