TNF and pulmonary arterial hypertension: In addition, expression of inflammatory cytokine genes related to PAH, i.e., TNFα, [105,156,157,158], interleukin (IL) 1β, IL6 [105,156,157,158], iNOS, and COX2 [105], were decreased in the PA and lungs of rats with hypoxia-induced PH transfected with M1 macrophage exosomes with miR-663b [105], or treated with the SIRT1 activator phoenixin-20 in hypoxic rats [158] or scutellarein in MCT-induced PH rats and hypoxia-induced PH mice [157], which was found to alleviate PH progression (Figure 2).