Abstract
Activated macrophages contribute to endothelial dysfunction; however, it is unclear how peroxynitrite contributes to macrophage-mediated human cardiac microvascular endothelial cell (HCMEC) injury in hypoxia. In macrophage-HCMEC co-cultures subjected to hypoxia, there was an increase in hypoxia-inducible factor (HIF)-1α, HIF-2α, inducible nitric oxide synthase (iNOS), endothelin-converting enzyme (ECE)-1 and cyclooxygenase-2 (COX-2), and concomitant decrease in prostacyclin synthase (PGIS). This was mimicked by a peroxynitrite donor and attenuated by its decomposition catalyst. Tongxinluo (TXL) could decrease HIF-2α, iNOS, ECE-1 and COX-2 and increase PGIS in a dose-dependent manner, with increase of vascular endothelial growth factor. The protein alterations verified the remarkably affected mRNAs, indicating that the effects of TXL were similar to but better than that of peroxynitrite decomposition catalyst. Furthermore, TXL inhibited macrophage-mediated nitrotyrosine accumulation and attenuated HCMEC injury. The results suggest that peroxynitrite contributes to macrophage-mediated HCMEC injury in hypoxia, and TXL attenuates HCMEC injury mainly by inhibiting peroxynitrite.
Highlights
Cardiovascular disease is a leading cause of death worldwide
After human cardiac microvascular endothelial cell (HCMEC) were co-cultured with macrophages and treated with CoCl2, HCMEC mRNA of hypoxia-inducible factor (HIF)-1a, HIF-2a, Vascular endothelial growth factor (VEGF), endothelial NOS (eNOS), inducible nitric oxide synthase (iNOS), endothelin-converting enzyme (ECE)-1, COX-2 and PGIS was measured at 24 h to verify the effects of macrophages in hypoxia-treated HCMECs
The cells were divided into Con, Hx, Hx þ Mu and Mu groups, and after 24 h treatment, mRNAs of HIF-1a, HIF2a, VEGF, eNOS, iNOS, Endothelin-converting enzyme-1 (ECE-1), COX-2 and PGIS in HCMECs were measured by real-time RT-PCR (Figure 1)
Summary
Cardiovascular disease is a leading cause of death worldwide. Atherosclerosis and the subsequent vessel destruction are the primary cause of ischemic diseases, such as stroke and coronary heart disease (Schiano et al, 2014; Tano & Gollasch, 2014). Vascular endothelial growth factor (VEGF) is a major target gene of HIFs, which promotes angiogenesis in hypoxia (Oh et al, 2015). Oxidative stress and inflammation have been widely accepted to be the key pathological processes of cardiac microvascular endothelial cells (Liu et al, 2014; Mangge et al, 2014). Inflammation and oxidative stressrelated genes can be activated by hypoxia (Shweta et al, 2014). Both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are inducible enzymes in inflammation and oxidative stress, and can cause pathological damage (Li et al, 2008; Tunctan et al, 2013). In addition to VEGF, HIFs contribute to the trans-activation of iNOS, ECE-1 and COX-2, which leads to injury (Branco-Price et al, 2012; Khamaisi et al, 2015; Zhao et al, 2015)
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