Inhibitory effects of resveratrol on foam cell formation are mediated through monocyte chemotactic protein-1 and lipid metabolism-related proteins.

Resveratrol has been shown to exert anti-atherosclerotic effects. 5' AMP-activated protein kinase (AMPK) and monocyte chemotactic protein-1 (MCP-1) play key roles in foam cell formation, which is considered as the initiation of atherosclerosis. Thus, in this study, we investigated whether resveratrol inhibits foam cell formation by regulating lipid accumulation and inflammation. For this purpose, THP-1 cells were treated with 100 nM phorbol 12-myristate 13-acetate (PMA) to induce their differentiation into macrophages. The macrophages were then pre-treated with 2.5 µM resveratrol and subsequently with serum-free (SF) medium alone or SF medium containing lipopolysaccharide (LPS; 100 ng/ml) and oxidized low-density lipoprotein (ox-LDL; 50 µg/ml) for 24 h to detect foam cell formation. To detect the expression of lipid accumulation-related proteins, the macrophages were treated with resveratrol. For the detection MCP-1 expression, the macrophages were treated with LPS and resveratrol, or with resveratrol alone. We incubated the THP-1-derived macrophages in resveratrol (2.5 µM) for 6 h in the presence or absence of 30 µM compound C for 4 h to detect the influence of compound C on the effects of resveratrol. The foam cells were examined using Red O staining. Gene expression levels were determined by qRT-PCR, western blot analysis and ELISA; lipid analysis was carried out by high-performance liquid chromatography (HPLC). The results revealed that resveratrol effectively suppressed foam cell formation induced by LPS. Resveratrol also suppressed lipid accumulation and downregulated the mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ and PPARα, but had no effect on the expression of PPARß/δ. Resveratrol also upregulated the expression of AMPK and Silent information regulator T1 (SIRT1). However, the effects of resveratrol on SIRT1, PPARγ and PPARα expression and lipid accumulation were reversed when the cells were pre-treated with compound C. Resveratrol downregulated the mRNA expression of MCP-1 in a dose-dependent manner and LPS upregulate its expression in a time-dependent manner. MCP-1 expression induced by LPS was inhibited by resveratrol at both the transcriptional and translational level. These data suggest that resveratrol inhibits foam cell formation by regulating the expression of MCP-1 and activating the AMPK-SIRT1-PPAR signaling pathway; thus, resveratrol may be a novel therapeutic agent for atherosclerosis.

Resveratrol ameliorates subacute intestinal ischemia-reperfusion injury.

BACKGROUND: Resveratrol has been shown to attenuate reactive oxygen species formation and protect against ischemia-reperfusion (I/R) injury. However, the effects of resveratrol against subacute intestinal I/R injury are not clearly elucidated. Therefore, this study was designed to investigate the effects and possible protective mechanisms of resveratrol on subacute intestinal I/R injury in mice. METHODS: BALB/c mice were subjected to 1 h ischemia by occluding the superior mesenteric artery and 24 h reperfusion. Histologic injury; myeloperoxidase, superoxide dismutase, and glutathione peroxidase activity; malondialdehyde level; inducible nitric oxide synthase (iNOS), Ac-NF-κBp65, and sirtuin 1 (SIRT1) expression; NF-κB translocation; and nitric oxide (NO) production were examined in treated with or without resveratrol in the absence or presence of pharmacologic inhibitors. RESULTS: Resveratrol significantly ameliorated subacute intestinal I/R injury accompanied with the decrease of NO production as well as iNOS expression. In addition, resveratrol obviously upregulated the expression of SIRT1 and inhibited the activity of NF-κB. After application of iNOS inhibitor S-methylisothiourea and NF-κB inhibitor pyrrolidine dithiocarbamate, the protective effect of resveratrol was significantly augmented by attenuating iNOS and NO production, indicating that resveratrol exerted its protective effect on intestinal I/R injury via NF-κB-mediated iNOS pathway. Furthermore, the protective effect of resveratrol was correlated with SIRT1, because application of SIRT1 inhibitor nicotinamide strikingly weakened the protective effect of resveratrol. CONCLUSIONS: Taken together, our findings showed that resveratrol protects intestinal subacute I/R injury via the SIRT1-NF-κB pathway in an iNOS-NO-dependent manner. Therefore, resveratrol has a potential clinical prospect for further development of anti-injury therapy.

SKF-96365 attenuates toxin-induced neuronal injury through opposite regulatory effects on Homer1a and Homer1b/c in cultured rat mesencephalic cells.

Disturbances in Ca(2+) homeostasis have been implicated in a variety of neuro-pathological conditions including Parkinson's disease (PD). In the present study, we investigated the potential protective effect of SKF-96365, an originally identified blocker of receptor-mediated calcium entry, on MPP(+) induced neuronal injury in cultured rat mesencephalic cells. We found that pretreatment with SKF-96365 30 min before injury significantly reduced nuclear damage, decreased LDH release and inhibited apoptotic neuronal death. The results of calcium image also showed that SKF-96365 inhibited the increase of intracellular calcium induced by MPP(+), which was not dependent on the expression and function of TRPC1. In addition, SKF-96365 increased the expression of Homer1a, but decreased the expression of Homer1b/c in the presence or absence of MPP(+). Furthermore, overexpression of Homer1a by using recombinant lentivirus and knockdown of Homer1b/c by short interfering RNA (siRNA) further enhanced protective effects of SKF-96365 against MPP(+) injury. Taken together, these data suggest that SKF-96365 protects cultured rat mesencephalic cells against MPP(+) induced cytotoxicity, and this protection may be at least in part dependent on attenuating intracellular calcium overload, opposite regulatory effects on Homer1a and Homer1b/c expressions.

Kallikrein genes are associated with lupus and glomerular basement membrane-specific antibody-induced nephritis in mice and humans.

Immune-mediated nephritis contributes to disease in systemic lupus erythematosus, Goodpasture syndrome (caused by antibodies specific for glomerular basement membrane [anti-GBM antibodies]), and spontaneous lupus nephritis. Inbred mouse strains differ in susceptibility to anti-GBM antibody-induced and spontaneous lupus nephritis. This study sought to clarify the genetic and molecular factors that maybe responsible for enhanced immune-mediated renal disease in these models. When the kidneys of 3 mouse strains sensitive to anti-GBM antibody-induced nephritis were compared with those of 2 control strains using microarray analysis, one-fifth of the underexpressed genes belonged to the kallikrein gene family,which encodes serine esterases. Mouse strains that upregulated renal and urinary kallikreins exhibited less evidence of disease. Antagonizing the kallikrein pathway augmented disease, while agonists dampened the severity of anti-GBM antibody-induced nephritis. In addition, nephritis-sensitive mouse strains had kallikrein haplotypes that were distinct from those of control strains, including several regulatory polymorphisms,some of which were associated with functional consequences. Indeed, increased susceptibility to anti-GBM antibody-induced nephritis and spontaneous lupus nephritis was achieved by breeding mice with a genetic interval harboring the kallikrein genes onto a disease-resistant background. Finally, both human SLE and spontaneous lupus nephritis were found to be associated with kallikrein genes, particularly KLK1 and the KLK3 promoter, when DNA SNPs from independent cohorts of SLE patients and controls were compared. Collectively, these studies suggest that kallikreins are protective disease-associated genes in anti-GBM antibody-induced nephritis and lupus.