Adenoviral gene transfer of viral interleukin-10 protects cerebrovascular impairment induced by lysophosphatidylcholine

VSMC-Specific Deletion of FAM3A Attenuated Ang II-Promoted Hypertension and Cardiovascular Hypertrophy

RATIONALE

Dysregulated purinergic signaling transduction plays important roles in the pathogenesis of cardiovascular diseases. However, the role and mechanism of vascular smooth muscle cell (VSMC)-released ATP in the regulation of blood pressure, and the pathogenesis of hypertension remain unknown. FAM3A (family with sequence similarity 3 member A) is a new mitochondrial protein that enhances ATP production and release. High expression of FAM3A in VSMC suggests it may play a role in regulating vascular constriction and blood pressure.

OBJECTIVE

To determine the role and mechanism of FAM3A-ATP signaling pathway in VSMCs in the regulation of blood pressure and the pathogenesis of hypertension.

METHODS AND RESULTS

In the media layer of hypertensive rat and mouse arteries, and the internal mammary artery of hypertensive patients, FAM3A expression was increased. VSMC-specific deletion of FAM3A reduced vessel contractility and blood pressure levels in mice. Moreover, deletion of FAM3A in VSMC attenuated Ang II (angiotensin II)-induced vascular constriction and remodeling, hypertension, and cardiac hypertrophy in mice. In cultured VSMCs, Ang II activated HSF1 (heat shock factor 1) to stimulate FAM3A expression, activating ATP-P2 receptor pathway to promote the change of VSMCs from contractile phenotype to proliferative phenotype. In the VSMC layer of spontaneously hypertensive rat arteries, Ang II-induced hypertensive mouse arteries and the internal mammary artery of hypertensive patients, HSF1 expression was increased. Treatment with HSF1 inhibitor reduced artery contractility and ameliorated hypertension of spontaneously hypertensive rats.

CONCLUSIONS

FAM3A is an important regulator of vascular constriction and blood pressure. Overactivation of HSF1-FAM3A-ATP signaling cascade in VSMCs plays important roles in Ang II-induced hypertension and cardiovascular diseases. Inhibitors of HSF1 could be potentially used to treat hypertension.

The effect of interleukin-10 on apoptosis in macrophages stimulated by oxLDL

Marked anti-atheromatous effects of the anti-inflammatory cytokine interleukin-10 (IL-10) were observed in several lipid-driven animal models of arteriosclerosis. We have previously demonstrated that IL-10 significantly inhibited lipid uptake in macrophages induced by oxLDL (Wang et al., 2008; Yang et al., 2008b). In this study, we investigated whether IL-10 affects the apoptosis related gene BCL2L11 and BMF expression in macrophages treated with oxLDL from THP-1 cells, which served as macrophage models. Cell apoptosis assays were performed by flow cytometry. Expression of the apoptosis related genes BCL2L11 and BMF mRNA was quantified by real-time RT-PCR (mRNA expression) and Western blotting (protein expression). IL-10 markedly blocked oxLDL induced cells undergoing early stage apoptosis. In the foam cell group, as compared with the macrophage group, the percentage of apoptosis increased by 100%. Here the expression of BCL2L11 was 45% (mRNA) and 41% (protein) elevated, while the expression of BMF was 54% (mRNA) and 44% (protein) elevated. When macrophages were co-stimulated by 100mg/l oxLDL and 20 μg/l IL-10 for 24h, compared with the foam cell group, the percentage of the apoptosis decreased by 21%, the expression of apoptosis related gene BMF was inhibited, the expression of mRNA and protein was both depressed by 23% and 20%, respectively, but the BCL2L11 expression was unchanged. These results may explain why decrement of early stage apoptosis cells was observed during co-stimulation and raise the possibility that IL-10 reduces foam cell undergoing apoptosis partly through down-regulating the expression of BMF, which demonstrates a critical role of IL-10 in anti-atherogenesis.