Single-Cell RNA Sequencing Reveals the Cellular Landscape of Longissimus Dorsi in a Newborn Suhuai Pig

Abstract

The introduction of single-cell RNA sequencing (scRNA-seq) technology has spurred additional advancements in analyzing the cellular composition of tissues. The longissimus dorsi (LD) in pigs serves as the primary skeletal muscle for studying meat quality in the pig industry. However, the single-cell profile of porcine LD is still in its infancy stage. In this study, we profiled the transcriptomes of 16,018 cells in the LD of a newborn Suhuai pig at single-cell resolution. Subsequently, we constructed a cellular atlas of the LD, identifying 11 distinct cell populations, including endothelial cells (24.39%), myotubes (18.82%), fibro-adipogenic progenitors (FAPs, 18.11%), satellite cells (16.74%), myoblasts (3.99%), myocytes (5.74%), Schwann cells (3.81%), smooth muscle cells (3.22%), dendritic cells (2.99%), pericytes (1.86%), and neutrophils (0.33%). CellChat was employed to deduce the cell–cell interactions by evaluating the gene expression of receptor–ligand pairs across different cell types. The results show that FAPs and pericytes are the primary signal contributors in LD. In addition, we delineated the developmental trajectory of myogenic cells and examined alterations in the expression of various marker genes and molecular events throughout various stages of differentiation. Moreover, we found that FAPs can be divided into three subclusters (NR2F2-FAPs, LPL-FAPs, and TNMD-FAPs) according to their biological functions, suggesting that the FAPs could be associated with the differentiation of tendon cell. Taken together, we constructed the cellular atlas and cell communication network in LD of a newborn Suhuai pig, and analyzed the developmental trajectory of myogenic cells and the heterogeneity of FAPs subpopulation cells. This enhances our comprehension of the molecular features involved in skeletal muscle development and the meat quality control in pigs.

The Impact of FBN1-α5β1 Axis in Fibro/Adipogenic Progenitor Cells (FAPCD9–) on Intramuscular Fat Content in Pigs

“…Previously, intramuscular vascular stem cells (IVSC), composed of satellite cells, FAPs, immune cells, and endothelial cells, − have been isolated from skeletal muscle of newborn piglets and used in adipogenesis studies. ,, However, the precise cellular origin of intramuscular fat cells remains unclear. Recently, single-cell RNA sequencing (scRNA-seq) has elucidated the diversity of cell population in tissues, providing insights into the heterogeneity of gene expression across cells. , Studies based on scRNA-seq have effectively revealed the molecular mechanisms underlying adipogenic formation in distinct regions of adipose tissue. − Several studies have also documented the single-cell mapping of porcine skeletal muscle, , revealing the involvement of FAPs in intramuscular fat deposition. , However, FAPs exhibit heterogeneity, and as of now, the precise origin of IMF remains unclear. Moreover, there are few investigations focusing on the differences in the adipogenic mechanism of FAPs between fat-type and lean-type pigs.…”