Acquisition of pig intramuscular preadipocytes through dedifferentiation of mature adipocytes and establishment of optimal induction conditions

Abstract

ABSTRACT. Intramuscular fat deposition is a major contributing factor to variations in pork quality. Understanding the mechanisms driving the differentiation and metabolism of muscle-derived adipocytes is important for regulating the fat deposition in muscle. Studies on intramuscular adipocytes commonly involve stromal-vascular (SV) cell cultures, which contain preadipocytes but also several other types of primordial cells. Hence, it is crucial to obtain pure intramuscular preadipocytes for investigating adipocyte differentiation and metabolism in muscle tissue. In this study, we established cultures of pure intramuscular preadipocytes that were derived from mature adipocytes of newborn pigs. Pure mature adipocytes were isolated from the longissimus dorsi (LD) muscle and allowed to dedifferentiate into fibroblast-like cells in ceiling culture. These fibroblast-like cells turned out to be preadipocytes; they exhibited the ability to redifferentiate into mature adipocytes when adipogenically induced in vitro. The redifferentiation process was confirmed by lipid accumulation Adipose-derived intramuscular preadipocytes of piglets in the cytoplasm and expression patterns of peroxisome proliferatoractivated receptor gamma 2 (PPARg2), CCAAT/enhancer binding protein alpha (C/EBPa), lipoprotein lipase (LPL), and adiponectin genes, which were all similar to those observed in previous preadipocyte studies. We optimized the induction conditions for intramuscular preadipocytes by adding 0.25 nM dexamethasone (DEX), 5 mg/mL insulin (INS), and 0.1 mM 3-isobutyl-1-methylxanthine (IBMX). Therefore, this study provides a new model for studying the mechanisms of intramuscular preadipocyte differentiation and metabolism.

Muscle-specific downregulation of GR levels inhibits adipogenesis in porcine intramuscular adipocyte tissue

“…DEX effect on the differentiation of SA and IMA pre-adipocytes was compared by treating pre-adipocytes with 2.5 μM DEX, which had been proved to be the optimal concentration for pre-adipocytes differentiation inducement 21 . On day 0 of treatment, SA and IMA pre-adipocytes were fibrous cells.…”

“…Backfat and longissimus dorsi (LD) muscle were isolated aseptically. The porcine pre-adipocytes were obtained through the “ceiling culture” method, isolated according to our previous report 21 . The backfat and LD muscle were washed and minced into approximately 1 mm 3 slices, then digested with 0.1% (w/v) Type I collagenase (Life Technologies, USA).…”

Knockdown of ubiquitin D inhibits adipogenesis during the differentiation of porcine intramuscular and subcutaneous preadipocytes

“…For the past few years, studies about IMF have become increasingly frequent in the field of porcine fat deposition. Thus, it is essential to study candidate genes that can control IMF deposition …”

“…Thus, it is essential to study candidate genes that can control IMF deposition. 4 Ubiquitin D (UBD) is an 18 kDa protein consisting of two ubiquitinlike (UBL) domains. 5 It is a member of UBL protein family that is encoded by the major histocompatibility class I locus and possesses 29% and 36% identity with the N-and C-terminus of ubiquitin, respectively.…”

Genetic variants in IL15 promoter affect transcription activity and intramuscular fat deposition in longissimus dorsi muscle of pigs

“…Primary preadipocytes were obtained through dedifferentiation of mature adipocytes from newborn pigs (Sun et al . ). Cells were routinely cultured in Dulbecco's Modified Eagle's Medium (DMEM) (Hyclone) containing 10% fetal bovine serum and 1% antibiotics.…”