DataSheet_1_Age-Related Alterations in Macrophage Distribution and Function Are Associated With Delayed Cutaneous Wound Healing.docx

Ageing-related delays and dysregulated inflammation in wound healing are well-documented in both human and animal models. However, cellular and molecular changes underlying this impairment in healing progression are not fully understood. In this study, we characterised ageing-associated changes to macrophages in wounds of young and aged mice and investigated transcriptomic differences that may impact the progression of wound healing. Full-thickness wounds created on the dorsum of C57BL/6J young and aged mice were excised on Days 3 and 7 post-wounding for analysis by immunohistochemistry, flow cytometry, and RNA sequencing. Our data revealed that macrophages were significantly reduced in aged wounds in comparison to young. Functional transcriptomic analyses showed that macrophages from aged wounds exhibited significantly reduced expression of cell cycle, DNA replication, and repair pathway genes. Furthermore, we uncovered an elevated pro-inflammatory gene expression program in the aged macrophages correlated with poor inflammation resolution and excessive tissue damage observed in aged wounds. Altogether, our work provides insights into how poorly healing aged wounds are phenotypically defined by the presence of macrophages with reduced proliferative capacity and an exacerbated inflammatory response, both of which are pathways that can be targeted to improve healing in the elderly.

创伤愈合过程中与衰老相关的愈合延迟及炎症失调现象，已在人类与动物模型中得到充分证实。然而，导致该愈合进程受损的细胞与分子机制尚未完全阐明。本研究对年轻与衰老小鼠创伤组织中的巨噬细胞（macrophages）进行衰老相关特征分析，并探究了可能影响创伤愈合进程的转录组差异。本研究于创伤后第3天和第7天，对年轻及衰老C57BL/6J小鼠背部创建的全层创伤组织进行取材，随后通过免疫组织化学（immunohistochemistry）、流式细胞术（flow cytometry）与RNA测序（RNA sequencing）开展分析。研究数据显示，相较于年轻小鼠创伤组织，衰老小鼠创伤中的巨噬细胞数量显著减少。功能转录组分析结果表明，衰老小鼠创伤来源的巨噬细胞，其细胞周期、DNA复制及修复通路相关基因的表达水平显著下调。此外，本研究发现衰老巨噬细胞中存在激活的促炎基因表达程序，该程序与衰老创伤中观察到的炎症消退不良及过度组织损伤密切相关。综上，本研究揭示了愈合不良的衰老创伤的表型特征：其创伤组织中存在增殖能力降低且炎症反应加剧的巨噬细胞，而这两类特征均可作为靶点，用于改善老年群体的创伤愈合效果。