Breed difference and regulatory role of CRTC3 in porcine intramuscular adipocyte

Abstract

SummaryThe cAMP responsive element binding protein (CREB)‐regulated transcription coactivator 3 (CRTC3) is a member of the CRTC protein family and plays an important role in energy metabolism. The aim of this study was to determine if the expression of porcine CRTC3 is related to intramuscular fat (IMF) deposition and meat quality in Heigai pigs (a local fatty breed in China) and Duroc × Landrace × Yorkshire (DLY) pigs (a lean crossbred pig widely cultured in China). In addition, the effect of ectopic expression of CRTC3 on gene expression in porcine IMF adipocytes was also examined. Our results showed that Heigai pigs had lower lean percentage, thicker back fat thickness and smaller loin muscle area than DLY pigs. Compared with DLY pigs, Heigai pigs had higher marbling scores, better meat color and higher IMF contents and triglyceride concentrations. Higher levels of oxidative metabolic enzyme and expression of the slow oxidative muscle fiber‐related genes were observed in longissimus dorsi muscle and psoas major muscle (P < 0.05) from Heigai pigs. Notably, CRTC3 and adipocyte‐specific marker genes were highly expressed in muscle tissues of Heigai pigs. The expression of lipolysis‐related genes ATGL and HSL were lower in Heigai muscles. Moreover, forced expression of CRTC3 promoted lipid accumulation and increased the expression of PPARγ, C/EBPα, leptin and FABP4 (P < 0.05), whereas it decreased the expression of ATGL and HSL in IMF adipocytes. These results suggest that CRTC3 expression is associated with lipid accumulation and IMF deposition in pigs.

Comprehensive evaluation of the metabolic effects of porcine CRTC3 overexpression on subcutaneous adipocytes with metabolomic and transcriptomic analyses

“…Previous studies demonstrated that CRTC3 is expressed at high levels in adipose tissues from different locations [16,22], and its expression is linked to skeletal muscle fat deposition [2,14], obesity and energy metabolism [16,18,20,25]. These findings suggest that CRTC3 plays an important regulatory role in fat deposition in mammals.…”

“…We observed higher expression levels of CRTC3 in SAT and VAT from Heigai pigs than DLY pigs. Likewise, CRTC3 expression has been shown to be associated with IMF content in pigs [2]. The genomic characterization of the CRTC3 gene might be associated with meat quality and fat deposition in pigs [26].…”

“…Pork, which is widely consumed globally, is an important source of animal protein for humans [1,2]. Methods to further improve pork quality for human consumption have received increasing attention in recent years.…”

“…Fat deposition influences growth efficiency, pork production and meat quality [3,4]. The deposition of subcutaneous and visceral fat directly influences backfat thickness and growth efficiency, while the intramuscular fat (IMF) content directly affects meat quality including the flavor, juiciness and tenderness as well as the fatty acid (FA) composition [2,3]. Thus, an understanding of fat deposition in pigs is critical for improving meat production and quality.…”

“…In our previous studies, we determined the regulatory role of CRTC3 in brown adipocytes and in intestinal epithelial cells [17,19,20,22]. We also studied the expression pattern of CRTC3 in skeletal muscle in Heigai pigs, which is a profitable pig breed in China that is characterized by high fat deposition, a low lean ratio, good meat color and high IMF contents [2]. In the present study, we aimed to compare the breed-specific difference in CRTC3 expression in SAT and visceral adipose tissue (VAT) between Heigai pigs (higher fat breed) and Duro-c×Landrace×Yorkshire (DLY) pigs (a lean crossbred pig breed).…”