Transcriptional and Functional Diversity of Macrophage Repolarization: Implications in Chronic Inflammation and Cystic Fibrosis

Macrophage plasticity allows cells to adopt different phenotypes, a property with potentially important implications in chronic pulmonary disorders such as cystic fibrosis (CF). We examined the transcriptional and functional significance of macrophage repolarization from an “M1” (LPS-stimulated) towards an “M2” phenotype using 5 stimuli. We found that macrophages exhibit highly diverse responses to distinct M2-polarizing stimuli. Specifically, we observed that IL-10 abrogated LPS-tolerance allowing for rapid restoration of LPS responsiveness. In contrast, IL-4 enhanced LPS-tolerance, dampening pro-inflammatory responses after repeat LPS challenge. We found enrichment of phagocytosis-associated pathways in macrophages stimulated with IL-10, leading them to display the greatest efferocytosis ability. Finally, we observed that CF macrophages had intact reparative responses, suggesting that macrophage contributions to CF lung disease are shaped by their environmental milieu and are modifiable. These findings highlight the diversity of macrophage activation states, attribute functional consequences to these stimuli, and provide a unique resource of human macrophage repolarization markers. Non-polarized, M0 state monocyte-derived macrophages (MDMs) from n= 6 cystic fibrosis (CF) patients and n =6 non-CF subjects were initially polarized to M1 by exposure to LPS. M1 MDMs were then cultured in MDM media alone (no treatment) or supplemented with IL-4, IL-10, methylprednisolone, azithromycin, or apoptotic PMNs for 24 h to repolarize MDMs towards an M2 state. Total RNA from each condition was isolated and hybridized to Illumina HumanHT-12 v4 BeadChip (total number of samples = 72).

巨噬细胞可塑性（Macrophage plasticity）可使细胞呈现多种不同表型，这一特性在囊性纤维化（cystic fibrosis, CF）等慢性肺部疾病中具有潜在的重要研究价值。本研究通过5种刺激物，探究了巨噬细胞从‘M1（脂多糖（lipopolysaccharide, LPS）刺激）表型’向‘M2表型’复极的转录与功能意义。我们发现，巨噬细胞对不同的M2极化刺激展现出高度多样化的应答。具体而言，白细胞介素-10（interleukin-10, IL-10）可解除LPS耐受，使细胞能够快速恢复对LPS的应答能力；与之相反，白细胞介素-4（interleukin-4, IL-4）则会增强LPS耐受，在再次受到LPS刺激时抑制促炎应答。我们还发现，经IL-10刺激的巨噬细胞中，与吞噬作用（phagocytosis）相关的通路发生富集，使其展现出最强的胞葬作用（efferocytosis）能力。最后，我们观察到CF来源的巨噬细胞仍具有完整的修复应答能力，这表明巨噬细胞对CF肺部疾病的贡献受其所处微环境的调控，且可被干预修饰。本研究结果凸显了巨噬细胞激活状态的多样性，明确了不同刺激物对应的功能效应，并为人类巨噬细胞复极标志物提供了独特的研究资源。本研究共纳入n=6名囊性纤维化（CF）患者与n=6名非CF受试者的非极化M0状态单核细胞源性巨噬细胞（monocyte-derived macrophages, MDMs）。首先将这些细胞经脂多糖（LPS）极化为M1表型，随后将M1型MDMs仅培养于MDM培养基（不予额外处理），或添加IL-4、IL-10、甲泼尼龙（methylprednisolone）、阿奇霉素（azithromycin）或凋亡性多形核中性粒细胞（polymorphonuclear neutrophils, PMNs）中培养24小时，使其向M2表型复极。提取各处理组的总RNA，与Illumina HumanHT-12 v4 BeadChip芯片进行杂交，最终共获得72个样本的检测数据。