Statin-mediated reduction in mitochondrial cholesterol primes an anti-inflammatory response in macrophages by upregulating Jmjd3.

Statins are known to be anti-inflammatory, but the mechanism remains poorly understood. Here, we show that macrophages, either treated with statin in vitro or from statin-treated mice, have reduced cholesterol levels and higher expression of Jmjd3, a H3K27me3 demethylase. We provide evidence that lowering cholesterol levels in macrophages suppresses the adenosine triphosphate (ATP) synthase in the inner mitochondrial membrane and changes the proton gradient in the mitochondria. This activates nuclear factor kappa-B (NF-κB) and Jmjd3 expression, which removes the repressive marker H3K27me3. Accordingly, the epigenome is altered by the cholesterol reduction. When subsequently challenged by the inflammatory stimulus lipopolysaccharide (M1), macrophages, either treated with statins in vitro or isolated from statin-fed mice, express lower levels proinflammatory cytokines than controls, while augmenting anti-inflammatory Il10 expression. On the other hand, when macrophages are alternatively activated by IL-4 (M2), statins promote the expression of Arg1, Ym1, and Mrc1. The enhanced expression is correlated with the statin-induced removal of H3K27me3 from these genes prior to activation. In addition, Jmjd3 and its demethylase activity are necessary for cholesterol to modulate both M1 and M2 activation. We conclude that upregulation of Jmjd3 is a key event for the anti-inflammatory function of statins on macrophages.

[Effect of triptolide on airway smooth muscle proliferation and the expression of nuclear factor-kappa B, Bcl-2 in asthmatic rats].

OBJECTIVE: To explore the effect of triptolide on airway remodeling and the expression of nuclear factor-kappaB, Bcl-2 in asthmatic rats. METHODS: 40 rats were randomly divided into 5 groups (n = 8): (1) Control group; (2) Asthmatic 4 week group; (3) Asthmatic 6 week group; (4) Therapeutic 4 week group; (5) Therapeutic 6 week group. The airway resistance and eosinophilic inflammation of airway wall were observed. The airway wall thickness (WA/Pi), the bronchial smooth muscle thickness (smooth muscle area/Pi) and the number of bronchial smooth muscle nucleus (N/Pi) were measured by image analysis system. The expression of PCNA, nuclear factor-kappaB and Bcl-2 protein were determined by immunohistochemical staining and Western blot. The expression of Bcl-2 mRNA was determined by reverse transcription-polymerase chain reaction(RT-PCR). RESULTS: (1) The expression of NF-kappaB protein in asthmatic 4 week group and asthmatic 6 week group was significantly higher than that in control group, respectively (P < 0.01). The above-mentioned parameters of therapeutic 6 week group were significantly lower than those of asthmatic 4 week group, asthmatic 6 week group and therapeutic 4 week group, respectively (P < 0.01, P < 0.01 P < 0.05). (2) The expression of Bcl-2 protein and mRNA of asthmatic 4 week group and asthmatic 6 week group were significantly higher than those in control group respectively (P < 0.01). The expression of Bcl-2 protein of therapeutic 6 week group was significantly lower than those of asthmatic 4 week group, asthmatic 6 week group and therapeutic 4 week group respectively (P < 0.05, P < 0.01, P < 0.01), but the expression of Bcl-2 mRNA was significantly higher than the above-mentioned groups respectively (P < 0.01), the expression of Bcl-2 protein and mRNA of therapeutic 6 week group were higher than control group respectively (P < 0.05, P < 0.01). (3) The expression of PCNA protein of asthmatic 4 week group and asthmatic 6 week group were significantly higher than those of control group respectively (P < 0.01). (4) The WA/ Pi, the smooth muscle area/Pi and the N/Pi of asthmatic 4 week group and asthmatic 6 week group were significantly higher than those of control group, respectively (P < 0.01). The above-mentioned parameters of therapeutic 6 week group were significantly lower than those of asthmatic 4 week group, asthmatic 6 week group and therapeutic 4 week group, respectively (P < 0.01). (5) The airway resistance of asthmatic 4 week group and asthmatic 6 week group were significantly higher than those of the control group, respectively (P < 0.01). The above-mentioned parameters of therapeutic 6 week group were significantly lower than those of asthmatic 4 week group, asthmatic 6 week group and therapeutic 4 week group, respectively (P < 0.01, P < 0.01, P < 0.05). CONCLUSION: The proliferation of airway smooth muscle(ASM) is related with apoptosis of airway smooth muscle cells in asthma. NF-kappaB may be involved in the process. Triptolide may prevent apoptosis of ASMCs and decrease the proliferation of ASM by inhibiting the expression of NF-kappaB, Bcl-2.