Porcine Aortic Endothelial Cells

Human IL-17 and TNF-α Synergistically Regulated the Expression of Various Immune-Related Genes in PAECs

Immune rejection is one of the most critical hurdles for prolonging survival time of porcine xenografts in primates. Although IL-17 and TNF-α are pivotal mediators in several immune disorders, their roles in xenotransplantation have not been well defined. Therefore, Li's team aimed to determine how hIL-17 and hTNF-α regulate gene expression and immune response in PAECs.

Treatment with human IL-17 (hIL-17) and human TNF-α (hTNF-α) altered the expression of 697 genes in PAECs, of which 315 genes were upregulated (166 synergistically and 149 additively), and 382 genes were downregulated (249 synergistically and 133 additively) (Fig. 1A). Functional annotation of DEGs using KEGG pathway analysis revealed enrichment of immune-associated signaling pathways including TNF-α signaling, IL-17 signaling, MAPK signaling, and Toll-like receptor signaling, cytokine-cytokine receptor interaction, etc. (Fig. 1B). When focused on signal transduction (n = 159), the immune system was found to be the most enriched category involving 86 genes (Fig. 1C). Among them, a series of proinflammatory cytokines (IL1α, IL6) and chemokines (CCL2, CCL11, CXCL8, CXCL2) were induced, while IL10 anti-inflammatory gene was inhibited. Ligand-receptor relationship analysis further identified that CCL11, IL1α, IL6, IL11 and their corresponding receptors were upregulated, whereas IL-10-IL10RB and KITLG-KIT were downregulated (Fig. 1D). RT-PCR validation showed that CCL20, CSF3, IL11, and CXCL2 were synergistically induced by IL-17 combined with TNF-α, whereas CCL11 and IL1α were additively induced by these cytokines (Fig. 2). These data are highly consistent with transcriptome sequencing results, demonstrating that hIL-17 and hTNF-α synergistically upregulated proinflammatory cytokines and chemokines to promote inflammation.