Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.
Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan.
Free Radic Biol Med. 2017 Nov;112:553-566. doi: 10.1016/j.freeradbiomed.2017.08.027. Epub 2017 Sep 1.
Recent studies have suggested a link between vascular dysfunction and innate immune activation including toll-like receptors (TLRs), but the detailed mechanism remains unclear. Here we investigated whether poly (I:C) [a synthetic double-strand RNA recognized by TLR3, melanoma differentiation-associated gene 5 (MDA5), and retinoic acid-inducible gene I (RIG-I)] affected nitric oxide (NO)/cGMP-related vascular relaxation, one of the major cascades of relaxation, in rat superior mesenteric arteries. Using organ-cultured arteries, we found that poly (I:C) (30μg/mL for approximately 1 day) markedly reduced sodium nitroprusside (SNP)-induced relaxation (vs. vehicle); this was prevented by co-treatment with a TLR3 inhibitor. Relaxation induced by 8-Br cGMP (a phosphodiesterase (PDE)-resistant cGMP analogue) and the expression of proteins related to NO/cGMP signaling did not differ between vehicle- and poly (I:C)-treated groups. When PDEs were inhibited by IBMX (a nonselective PDE inhibitor), the SNP-induced relaxation was still greatly reduced in poly (I:C)-treated arteries (vs. vehicle). Poly (I:C) reduced SNP-stimulated cGMP production, but increased NO production and iNOS expression (vs. vehicle). The impairment of SNP-induced relaxation by poly (I:C) was prevented by co-treatment with either iNOS or a nuclear factor-kappa B (NF-κB) inhibitor. This effect induced by poly (I:C) appeared to be independent of oxidative stress. The SNP-induced relaxation was reduced in freshly isolated arteries by pre-incubation with SNP in a concentration-dependent manner. Poly (I:C) did not alter protein levels of TLR3, TRIF/TICAM-1, or phospho-IRF3/IRF3, whereas RIG-I and MDA5 were significantly upregulated (vs. vehicle). These results suggest that poly (I:C) impairs NO donor-induced relaxation in rat superior mesenteric arteries via overexposure to NO produced by the NF-κB/iNOS pathway.
最近的研究表明，血管功能障碍与先天免疫激活之间存在关联，包括 Toll 样受体（TLRs），但详细机制尚不清楚。在这里，我们研究了聚（I：C）[一种被 TLR3、黑色素瘤分化相关基因 5（MDA5）和视黄酸诱导基因 I（RIG-I）识别的合成双链 RNA]是否会影响大鼠肠系膜上动脉中主要弛豫途径之一的一氧化氮（NO）/cGMP 相关血管弛豫。通过器官培养的动脉，我们发现聚（I：C）（约 1 天 30μg/mL）显着降低了硝普钠（SNP）诱导的松弛（与载体相比）；这可以通过与 TLR3 抑制剂共同处理来预防。与载体处理组相比，8-Br-cGMP（一种磷酸二酯酶（PDE）抗性 cGMP 类似物）诱导的松弛和与 NO/cGMP 信号相关的蛋白质的表达没有差异。当 PDE 被 IBMX（一种非选择性 PDE 抑制剂）抑制时，聚（I：C）处理的动脉中 SNP 诱导的松弛仍然大大降低（与载体相比）。聚（I：C）降低了 SNP 刺激的 cGMP 产生，但增加了 NO 产生和 iNOS 表达（与载体相比）。聚（I：C）预处理可防止 SNP 诱导的松弛被 iNOS 或核因子-κB（NF-κB）抑制剂共同处理。聚（I：C）诱导的这种作用似乎独立于氧化应激。与载体相比，聚（I：C）预处理以浓度依赖的方式降低了 SNP 诱导的新鲜分离动脉的松弛。聚（I：C）不改变 TLR3、TRIF/TICAM-1 或磷酸化 IRF3/IRF3 的蛋白水平，但 RIG-I 和 MDA5 的表达显著上调（与载体相比）。这些结果表明，聚（I：C）通过 NF-κB/iNOS 途径过度暴露于由其产生的 NO，损害了大鼠肠系膜上动脉中 NO 供体诱导的松弛。
