Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, USA.
Department of Orthopedics, Washington University School of Medicine, St. Louis, Missouri, USA.
J Clin Invest. 2023 Apr 17;133(8):e167311. doi: 10.1172/JCI167311.
Immune cells play an important functional role in bone fracture healing. Fracture repair is a well-choreographed process that takes approximately 21 days in healthy mice. While the process is complex, conceptually it can be divided into four overlapping stages: inflammation, cartilaginous callus formation, bony callus formation, and remodeling. T cells play a key role in both the cartilaginous and bony callus phases by producing IL-17A. In this issue of the JCI, Dar et al. showed that T cells were recruited from the gut, where the gut microbiota determined the pool of T cells that expressed IL-17A. Treatment with antibiotics and dysbiosis reduced the expansion of IL-17-expressing CD4+ T cells (Th17) and impaired callus formation. These findings demonstrate crosstalk among the gut microbiota, the adaptive immune system, and bone that has clinical implications for fracture healing.
免疫细胞在骨折愈合中发挥着重要的功能作用。骨折修复是一个精心编排的过程，在健康的小鼠中大约需要 21 天。虽然这个过程很复杂，但从概念上讲，它可以分为四个重叠的阶段：炎症、软骨性骨痂形成、骨性骨痂形成和重塑。T 细胞通过产生 IL-17A 在软骨性和骨性骨痂阶段发挥关键作用。在本期 JCI 中，Dar 等人表明，T 细胞是从肠道招募而来的，肠道微生物群决定了表达 IL-17A 的 T 细胞池。抗生素治疗和菌群失调会减少表达 IL-17A 的 CD4+T 细胞（Th17）的扩增，并损害骨痂形成。这些发现表明肠道微生物群、适应性免疫系统和骨骼之间存在相互作用，这对骨折愈合具有临床意义。
