Michigan Scleroderma Program, Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Michigan Scleroderma Program, Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
J Invest Dermatol. 2023 Oct;143(10):1877-1885. doi: 10.1016/j.jid.2023.04.030. Epub 2023 Jul 14.
Damage-associated molecular patterns (DAMPs) are intracellular molecules released under cellular stress or recurring tissue injury, which serve as endogenous ligands for toll-like receptors (TLRs). Such DAMPs are either actively secreted by immune cells or passively released into the extracellular environment from damaged cells or generated as alternatively spliced mRNA variants of extracellular matrix (ECM) glycoproteins. When recognized by pattern recognition receptors (PRRs) such as TLRs, DAMPs trigger innate immune responses. Currently, the best-characterized PRRs include, in addition to TLRs, nucleotide-binding oligomerization domain-like receptors, RIG-I-like RNA helicases, C-type lectin receptors, and many more. Systemic sclerosis (SSc) is a chronic autoimmune condition characterized by inflammation and progressive fibrosis in multiple organs. Using an unbiased survey for SSc-associated DAMPs, we have identified the ECM glycoproteins fibronectin-containing extra domain A and tenascin C as the most highly upregulated in SSc skin and lung biopsies. These DAMPs activate TLR4 on resident stromal cells to elicit profibrotic responses and sustained myofibroblasts activation resulting in progressive fibrosis. This review summarizes the current understanding of the complex functional roles of DAMPs in the progression and failure of resolution of fibrosis in general, with a particular focus on SSc, and considers viable therapeutic approaches targeting DAMPs.
损伤相关分子模式(DAMPs)是细胞应激或反复组织损伤下释放的细胞内分子,它们作为 Toll 样受体(TLRs)的内源性配体。这些 DAMPs 要么由免疫细胞主动分泌,要么从受损细胞被动释放到细胞外环境中,要么作为细胞外基质(ECM)糖蛋白的可变剪接 mRNA 变体产生。当被模式识别受体(PRRs)如 TLRs 识别时,DAMPs 会引发先天免疫反应。目前,除 TLRs 外,最好表征的 PRRs 还包括核苷酸结合寡聚化结构域样受体、RIG-I 样 RNA 解旋酶、C 型凝集素受体等。系统性硬化症(SSc)是一种慢性自身免疫性疾病,其特征是多个器官的炎症和进行性纤维化。通过对 SSc 相关 DAMPs 的无偏调查,我们已经确定 ECM 糖蛋白纤维连接蛋白包含的外显子 A 和 tenascin C 是 SSc 皮肤和肺活检中上调最明显的。这些 DAMPs 激活驻留基质细胞上的 TLR4,引发促纤维化反应,并持续激活肌成纤维细胞,导致进行性纤维化。本综述总结了 DAMPs 在纤维化进展和消退失败中的复杂功能作用的最新认识,特别是针对 SSc,并考虑了针对 DAMPs 的可行治疗方法。