# Single-Cell Cloning and Transcriptomic Analysis Support a Myogenic Origin of Bovine Intramuscular Adipocytes

## TL;DR

This study shows that some fat cells in cattle muscle likely come from muscle stem cells, which can turn into both muscle and fat cells.

## Contribution

The study provides evidence that bovine intramuscular adipocytes may originate from satellite cells, a novel finding in adipocyte lineage.

## Key findings

- IMF-derived preadipocyte clones expressed high levels of muscle-specific genes like MYOG and MYH3.
- Satellite cells can differentiate into both myocytes and adipocytes under specific conditions.
- Muscle-related functions were enriched in IMF-derived preadipocyte clones compared to SF-derived ones.

## Abstract

Intramuscular fat (IMF) refers to the adipose tissue located between muscle fibers and is a major determinant of meat quality in cattle. The cellular origin of bovine intramuscular adipocytes remains unclear. Therefore, the objective of this study was to investigate this origin. We derived single-preadipocyte clones from IMF and subcutaneous fat (SF) of cattle through single-cell cloning and subsequent validation of their potential to differentiate into adipocytes. Transcriptomic analysis of selected single-preadipocyte clones revealed that although both IMF- and SF-derived preadipocyte clones expressed classical preadipocyte markers such as PDGFRA, DLK1, and ZNF423, they differed significantly in global gene expression profile. Notably, many muscle-specific genes (e.g., MYOG, MB, and MYH3) were expressed at high levels in IMF-derived preadipocyte clones while not expressed in SF-derived clones. Functional enrichment analysis of differentially expressed genes between IMF- and SF-derived preadipocyte clones indicated that many muscle-related functions were enriched in the former. Furthermore, high-level expression of muscle-specific genes persisted in mature adipocytes differentiated from IMF-derived preadipocyte clones. We also found that bovine satellite cells, the widely considered progenitor cells of myocytes in postnatal animals, had the ability to form both myocytes and adipocytes under respective differentiation conditions. Based on these findings, we conclude that in cattle, at least some intramuscular adipocytes are derived from satellite cells.