Transcriptional Analysis of Skeletal Muscle Development in Adult and Juvenile Bactrian Camels Using Single-Cell RNA Sequencing

Baojun De^1*Yiyi Liu¹Lu Li¹Fanhua Meng¹Yuwen Liu²Ting Jia¹Yuting Chen¹Shenyuan Wang¹Tao Li¹Hongmei Xiao¹Fang Wan¹Yingchun Liu¹Wenlong Wang¹Huanmin Zhou¹Wenguang Zhang¹Xin Wen¹Jie Gong¹Naer A¹Hongmei Bao¹Qian Song¹chaolu HaSi³Hai Long³Yanru Zhang^1*JunWei Cao^1*

• ¹College of Life Sciences, Inner Mongolia Agricultural University, Huhhot, China
• ²Chinese Academy of Agricultural Sciences Agricultural Genomics Institute at Shenzhen, Shenzhen, China
• ³Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences Agricultural and Pastoral Economy and Information Research Institute, Hohhot, China

Skeletal muscle, as a structurally and functionally complex heterogeneous tissue, requires comprehensive understanding of its cellular heterogeneity and transcriptional characteristics to elucidate its developmental mechanisms. In this study, we performed single-cell RNA sequencing (scRNA-seq) analysis of skeletal muscle from juvenile and adult Bactrian camels, combined with CellChat toolkit to construct intercellular communication networks. We identified 14 distinct cell clusters across two developmental stages, encompassing muscle, neural, immune, and adipose cell types, and successfully characterized signature genes for each cell type. Cell proportion analysis revealed that adult muscle tissue is predominantly composed of neuromuscular cells and type IIx muscle fibers, with notable differences in cellular composition between juvenile and adult stages. Through pseudotime trajectory analysis, we unveiled the differentiation dynamics and gene expression patterns of myogenic cell subpopulations. Further CellChat analysis highlighted the pivotal role of fibro-adipogenic progenitor (FAP) cells in the signaling network, which can be subdivided into four functionally distinct subgroups: MME+, GPC6+, NRAP+, and MYO1E+, with the MME+ subpopulation potentially playing a crucial role in adipocyte differentiation. By establishing a cellular atlas and intercellular communication network of Bactrian camel skeletal muscle development, and thoroughly analyzing FAP subpopulation heterogeneity, this study provides crucial theoretical foundation and data support for understanding mammalian skeletal muscle development and functional regulation. These findings not only deepen our understanding of the molecular mechanisms underlying skeletal muscle development and meat quality regulation in Bactrian camels but also lay a foundation for future research in related fields.