Brorson Jonas, Lin Lin, Wang Jakob, Bæk Amanda, Billeskov Tine Borum, Thybo Frederik Forsberg, Just Jesper, Haskó János, Ravn Christen, Hansen Rehne L, Bue Mats, Jørgensen Jens Otto Lunde, Luo Yonglun, Jessen Niels, Farup Jean
Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark.
Department of Biomedicine, Aarhus University, Aarhus, Denmark.
Nat Commun. 2025 Jun 5;16(1):5233. doi: 10.1038/s41467-025-60627-2.
The capacity to regenerate skeletal muscle after injury requires a complex and well-coordinated cellular response, which is challenged in aged skeletal muscle. Here, we unravel the intricate dynamics of elderly human skeletal muscle regeneration by combining spatial, temporal, and single cell transcriptomics. Using spatial RNA sequencing (n = 3), we profile the expression of human protein-coding genes in elderly human skeletal muscle biopsies before as well as 2-, 8-, and 30-day post injury (NCT03754842). Single Cell-Spatial deconvolution analysis highlights monocytes/macrophages and fibro-adipogenic progenitors (FAPs) as pivotal players in human muscle regeneration. By utilizing flow cytometry (n = 9) and cell sorting we confirm the increased cellular content and activity during regeneration. Spatial correlation analysis unveils FAPs and monocytes/macrophages co-localization and intercellular communication, mediated by complement factor C3. Immunostaining confirms C3 expression in FAPs and FAP secretion of C3, suggesting a role in phagocytosis of necrotic muscle cells. Finally, functional assays demonstrate C3's impact on human monocyte metabolism, survival and phagocytosis, unveiling its involvement in skeletal muscle regeneration. These insights elucidate the FAP-macrophage interplay in aged human muscle with perspectives for future therapeutic interventions to reduce the age-induced decline in regenerative capacity.
损伤后骨骼肌再生的能力需要复杂且协调良好的细胞反应，而老年骨骼肌的这种反应受到挑战。在此，我们通过结合空间、时间和单细胞转录组学来揭示老年人类骨骼肌再生的复杂动态。使用空间RNA测序（n = 3），我们对老年人类骨骼肌活检样本在损伤前以及损伤后2天、8天和30天的人类蛋白质编码基因表达进行了分析（NCT03754842）。单细胞空间反卷积分析突出了单核细胞/巨噬细胞和成纤维脂肪生成祖细胞（FAPs）是人类肌肉再生的关键参与者。通过利用流式细胞术（n = 9）和细胞分选，我们证实了再生过程中细胞含量和活性的增加。空间相关性分析揭示了FAPs与单核细胞/巨噬细胞的共定位和细胞间通讯，这是由补体因子C3介导的。免疫染色证实了FAPs中C3的表达以及FAPs分泌C3，表明其在坏死肌细胞吞噬作用中发挥作用。最后，功能测定证明了C3对人类单核细胞代谢、存活和吞噬作用的影响，揭示了其参与骨骼肌再生。这些见解阐明了老年人类肌肉中FAP - 巨噬细胞的相互作用，为未来减少年龄诱导的再生能力下降的治疗干预提供了思路。
