背景:炎症是伤口愈合过程的重要组成部分。已证明应激激素肾上腺素通过其与β2-肾上腺素能受体(β2-AR)的相互作用来调节炎症反应。然而,β2-AR在伤口愈合过程中对炎症产生影响的确切分子机制仍未解决。
方法:使用生物信息学重新分析来自GEO数据库的伤口和巨噬细胞的转录组数据集。通过小鼠后爪足底伤口模型探讨了β2-AR在伤口愈合中的作用,和组织学分析进行评估伤口愈合。进行体内和体外测定以阐明β2-AR在炎症反应中的作用。用siRNA在RAW细胞上敲低在骨髓细胞1上表达的触发受体(Treml),并进行蛋白质印迹和qPCR测定。
结果:Trem1在受伤后24小时内上调,和巨噬细胞β2-AR激活也上调Trem1。体内实验表明,β2-AR激动剂损害伤口愈合,伴随着Trem1的上调和cAMP/PKA/CREB通路的激活,以及高水平的促炎细胞因子产生。体外实验表明巨噬细胞β2-AR的激活放大了LPS诱导的炎症,Trem1的击倒逆转了这一效应。使用cAMP的激活剂和抑制剂,证实巨噬细胞β2-AR激活通过cAMP/PKA/CREB途径上调Trem1。
结论:我们的研究发现β2-AR激动剂增加创伤中Trem1的表达,伴随着炎症反应的放大,损害伤口愈合。RAW细胞中的β2-AR激活通过cAMP/PKA/CREB途径诱导Trem1上调,并放大LPS诱导的炎症反应。
BACKGROUND: Inflammation is an important part of the wound healing process. The stress hormone epinephrine has been demonstrated to modulate the inflammatory response via its interaction with β2-adrenergic receptor (β2-AR). However, the precise molecular mechanism through which β2-AR exerts its influence on inflammation during the wound healing process remains an unresolved question.
METHODS: Transcriptome datasets of wound and macrophages from the GEO database were reanalyzed using bioinformatics. The role of β2-AR in wound healing was explored by a mouse hind paw plantar wound model, and histological analyses were performed to assess wound healing. In vivo and in vitro assays were performed to elucidate the role of β2-AR on the inflammatory response. Triggering receptor expressed on myeloid cells 1 (Trem1) was knocked down with siRNA on RAW cells and western blot and qPCR assays were performed.
RESULTS: Trem1 was upregulated within 24 h of wounding, and macrophage β2-AR activation also upregulated Trem1. In vivo experiments demonstrated that β2-AR agonists impaired wound healing, accompanied by upregulation of Trem1 and activation of cAMP/PKA/CREB pathway, as well as by a high level of pro-inflammatory cytokine production. In vitro experiments showed that macrophage β2-AR activation amplified LPS-induced inflammation, and knockdown of Trem1 reversed this effect. Using activator and inhibitor of cAMP, macrophage β2-AR activation was confirmed to upregulate Trem1 via the cAMP/PKA/CREB pathway.
CONCLUSIONS: Our study found that β2-AR agonists increase Trem1 expression in wounds, accompanied by amplification of the inflammatory response, impairing wound healing. β2-AR activation in RAW cells induces Trem1 upregulation via the cAMP/PKA/CREB pathway and amplifies LPS-induced inflammatory responses.