miR-210 promotes the anti-inflammatory phenotype and M2 polarization in murine macrophages

Abstract Introduction: Macrophages play fundamental roles in immune regulation and tissue homeostasis, serving as one of the primary cell types that orchestrate tissue repair after injury. MiR-210 is a hypoxia-inducible, small non-coding RNA involved in regulating metabolic adaptation and inflammatory responses during normal repair processes. However, its role in macrophage polarization is not fully understood. Here, we report the impact of miR-210 deletion on macrophage polarization towards a pro-reparatory phenotype. Methods: Bone marrow-derived macrophages were obtained from miR-210 knockout (KO) and wild-type (WT) mice and polarized toward the pro-reparative M2 phenotype. The transcriptomic profile of these cells, as well as their phagocytic capacity, cell energy phenotype, and cytokine production were assessed to determine the impact of miR-210 on the macrophage polarization process into a M2-like phenotype. Results: Compared with their WT counterparts, miR-210 KO M0 macrophages presented a reduced glycolytic activity and a diminished metabolic flexibility. However, miR-210 KO cells exhibited increased phagocytosis in both M0 and M2 states, potentially as an adaptive response to their metabolic limitations. Transcriptomic analysis revealed distinct clustering between the M0 and M2 states, along with several notable differences in the transcriptional patterns between the two genotypes. Analysis of differentially expressed genes indicated an increased pro-inflammatory state in resting miR-210 KO macrophages compared to WT control cells. These data were further confirmed by the higher levels of IL-6, TNF-α, and IL-1b secreted by miR-210 KO M0 macrophages compared to WT cells. Analysis of the biological processes activated during the polarization process towards the M2 phenotype revealed an incomplete polarization of miR-210 KO cells, which may be attributed, at least in part, to reduced activation of mitotic regulators, leading to slower cell cycle progression and diminished proliferation. Discussion: Our data offers new insights into the role of miR-210 in promoting a macrophage shift toward the anti-inflammatory, pro-reparative M2 phenotype. The fine-tuned involvement of miR-210 in immune responses may have potential implications for chronic inflammation, immune dysfunction, and tissue repair. Keywords: cell cycle; inflammation; macrophages; metabolism; miR-210; polarization.摘要 引言：巨噬细胞（Macrophages）在免疫调控与组织稳态中发挥核心作用，作为协调损伤后组织修复的主要细胞类型之一。微小RNA-210（miR-210）是一种缺氧诱导型小分子非编码RNA，参与正常修复过程中的代谢适应与炎症反应调控，但其在巨噬细胞极化中的作用尚未完全阐明。本研究探讨了miR-210敲除对巨噬细胞极化为促修复表型的影响。 方法：本研究从miR-210基因敲除（KO）与野生型（WT）小鼠中分离骨髓来源的巨噬细胞（bone marrow-derived macrophages），并将其极化为促修复的M2表型。通过检测这些细胞的转录组谱（transcriptomic profile）、吞噬能力、细胞能量表型及细胞因子产生情况，明确miR-210对巨噬细胞极化为M2样表型过程的影响。 结果：与野生型对照细胞相比，miR-210敲除的M0巨噬细胞糖酵解活性降低，代谢灵活性下降。然而，miR-210敲除细胞在M0与M2状态下均表现出增强的吞噬能力，这可能是对其代谢缺陷的适应性应答。转录组分析显示，M0与M2状态间存在明显的聚类分群，且两种基因型间的转录模式存在多处显著差异。差异表达基因分析表明，静息状态的miR-210敲除巨噬细胞较野生型对照细胞呈现更强的促炎状态，这一结果进一步通过miR-210敲除M0巨噬细胞分泌更高水平的IL-6、TNF-α及IL-1β得到验证。对M2极化过程中激活的生物学过程分析显示，miR-210敲除细胞的极化不完全，这至少部分归因于有丝分裂调控因子的激活水平降低，进而导致细胞周期进程减慢与增殖能力下降。 讨论：本研究结果为miR-210在促进巨噬细胞向抗炎、促修复的M2表型转化中的作用提供了新见解。miR-210在免疫反应中的精细调控作用，可能对慢性炎症、免疫功能异常及组织修复具有潜在的应用价值。 关键词：细胞周期；炎症；巨噬细胞；代谢；miR-210；极化。