Departments of Oral Biology, College of Dentistry, University of Illinois at Chicago, Chicago, IL 60612, United States of America.
Periodontics, College of Dentistry, University of Illinois at Chicago, Chicago, IL 60612, United States of America.
Bone. 2020 Dec;141:115627. doi: 10.1016/j.bone.2020.115627. Epub 2020 Sep 3.
Multiple local and systemic factors including inflammation influence bone regeneration. Several lines of evidence demonstrate that macrophages contribute to the immunological regulation of MSC and osteoblast function during bone regeneration. Recent studies demonstrate that macrophage polarization influences this regulatory process. In this manuscript, we investigated the paracrine functional role of naïve (M0), M1 and M2 polarized macrophage derived EVs in bone repair. Treatment of rat calvaria defects with no EVs, M0 EVs, M1 EVs, or M2 EVs revealed polarization-specific control of bone regeneration by macrophage EVs at 3 and 6 weeks. M0 and M2 EVs promoted repair/regeneration and M1 EVs inhibited bone repair. Pathway-specific studies conducted in cell culture showed that M1 EVs negatively regulated the BMP signaling pathway, specifically BMP2 and BMP9. In parallel, miRNA sequencing studies showed similar miRNA cargo in M0 and M2 EVs and different miRNA cargo in M1 EVs. Functional examination of M1 macrophage EV-enriched miR-155 demonstrated that miR-155 mimic treatment reduced MSC osteogenic differentiation as measured by reduced BMP2, BMP9 and RUNX2 expression when compared to controls. Conversely, treatment of MSCs with the M2 macrophage EV-enriched miR-378a mimic increased MSC osteoinductive gene expression when compared to controls. These functional studies implicate polarized macrophage EV miRNAs in the positive or negative regulation of bone regeneration that was observed in vivo. Overall, the results presented in this study indicate that macrophage polarization influences EV cargo and related EV function in the paracrine regulation of bone regeneration.
多种局部和全身因素包括炎症影响骨再生。有几条证据表明，巨噬细胞有助于在骨再生过程中调节间充质干细胞和成骨细胞的免疫功能。最近的研究表明，巨噬细胞极化影响这一调节过程。在本手稿中，我们研究了幼稚（M0）、M1 和 M2 极化的巨噬细胞衍生 EVs 在骨修复中的旁分泌功能作用。用无 EVs、M0 EVs、M1 EVs 或 M2 EVs 处理大鼠颅骨缺损，结果显示巨噬细胞 EVs 在第 3 周和第 6 周对骨再生具有极化特异性控制作用。M0 和 M2 EVs 促进修复/再生，而 M1 EVs 抑制骨修复。细胞培养中的通路特异性研究表明，M1 EVs 负调控 BMP 信号通路，特别是 BMP2 和 BMP9。同时，miRNA 测序研究显示 M0 和 M2 EVs 具有相似的 miRNA 载物，而 M1 EVs 具有不同的 miRNA 载物。对 M1 巨噬细胞 EV 富含的 miR-155 的功能研究表明，与对照组相比，miR-155 模拟物处理降低了 MSC 成骨分化，表现为 BMP2、BMP9 和 RUNX2 表达减少。相反，用 M2 巨噬细胞 EV 富含的 miR-378a 模拟物处理 MSC，与对照组相比，增加了 MSC 成骨诱导基因表达。这些功能研究表明，极化的巨噬细胞 EV miRNA 参与了体内观察到的骨再生的正或负调节。总的来说，本研究的结果表明，巨噬细胞极化影响 EV 载物和相关 EV 功能，在旁分泌调节骨再生中发挥作用。
