Lipid deposition is related to agricultural animal production and human health, and elucidating its molecular regulatory mechanisms is a topic of interest and a challenge in current scientific research. Musculoskeletal embryonic nuclear protein 1 (MUSTN1) regulates growth and development, including muscle tissue; however, its role in fat deposition remains unknown. Thus, our objective was to determine this role. Our new findings were as follows: MUSTN1 was highly expressed in the fat tissue of pigs with strong adipose deposition capacity; functionally, MUSTN1 promoted the proliferation and adipogenic differentiation of porcine and mouse preadipocytes. MUSTN1 knockout mice were protected against HFD-induced obesity, hepatic steatosis, and insulin resistance; and fatty acid binding protein 3 was identified as an interacting protein of MUSTN1, which facilitated preadipocyte proliferation and differentiation by activating the phosphatidylinositol 3 kinase/AKT signaling pathways. This study reveals a positive regulator for fat development, which suggesting a novel approach for studying obesity and animal genetic improvement through the modulation of MUSTN1 expression.

Pig growth involves multiple genes and coordinated regulatory mechanisms. The large Diqing Tibetan pigs (TPs) are a unique plateau pig breed in China. Data on the mechanisms of muscle growth and development in TPs are limited, and its transcriptional regulation mechanism remains unclear. This study identifies important genes and proteins involved in muscle growth in TPs. We obtained transcriptomic and proteomic data from the longissimus dorsi muscle tissues of TPs and Duroc pigs (DPs) via RNA-seq and isobaric tags for relative and absolute quantitation analyses, respectively. Comparative analyses of TPs and DPs yielded 557 differentially expressed genes (DEGs) and 56 differentially abundant proteins (DAPs). Functional annotation of these DEGs and DAPs was enriched in metabolic processes, metabolic pathways, cytoskeletal protein binding, AMPK signaling pathway, insulin signaling pathway, PPAR signaling pathway, and other related pathways. Ten genes were identified as key candidate regulators (FASN, PPARG, PCK1, ACTA2, TXN, SNU13, APOA1, ATP8, ALDH2, and IGFN1) that may play important roles in the muscle growth traits of TPs. This study provides a reference for analyzing the genetic regulation mechanism underlying muscle growth in pigs and improving the meat yield of TPs via molecular marker-assisted selection.

Meat yield, determined by muscle growth and development, is an important economic trait for the swine industry and a focus of research in animal genetics and breeding. PDZ and LIM domain 5 (PDLIM5) are cytoskeleton-related proteins that play key roles in various tissues and cells. These proteins have multiple isoforms, primarily categorized as short (PDLIM5-short) and long (PDLIM5-long) types, distinguished by the absence and presence of an LIM domain, respectively. However, the expression patterns of swine PDLIM5 isoforms and their regulation during porcine skeletal muscle development remain largely unexplored. We observed that PDLIM5-long was expressed at very low levels in pig muscles and that PDLIM5-short and total PDLIM5 were highly expressed in the muscles of slow-growing pigs, suggesting that PDLIM5-short, the dominant transcript in pigs, is associated with a slow rate of muscle growth. PDLIM5-short suppressed myoblast proliferation and myogenic differentiation in vitro. We also identified two single nucleotide polymorphisms (−258 A > T and −191 T > G) in the 5′ flanking region of PDLIM5, which influenced the activity of the promoter and were associated with muscle growth rate in pigs. In summary, we demonstrated that PDLIM5-short negatively regulates myoblast proliferation and differentiation, providing a theoretical basis for improving pig breeding programs.

Adipose tissue, an important organ involved in energy metabolism and endocrine, is closely related to animal meat quality and human health. Transient receptor potential channel 1 (TRPC1), an ion transporter, is adipocytes' major Ca²⁺ entry channel. However, its function in fat deposition is poorly understood, particularly in pigs, which are both an ideal model for human obesity research and a primary meat source for human diets. In the present investigation, our findings demonstrate a prominent expression of TRPC1 within the adipose tissue of pigs with a strong fat deposition ability. Functional analysis showed that TRPC1 promotes primary preadipocyte proliferation and adipogenic differentiation. In vivo, transgenic mice expressing porcine TRPC1 exhibited aggravated high-fat diet-induced obesity, hepatic steatosis, and insulin resistance. Moreover, TRPC1 may facilitate adipogenesis via activating phosphatidylinositol 3 kinase/AKT and β-catenin signaling pathways. Our research underscores the pivotal role of porcine TRPC1 as a positive regulator in adipogenesis and lipid accumulation processes, providing a potential target for improving animal meat quality and treating obesity-related diseases in humans.

Secreted frizzled-related protein 3 (sFRP3/FRZB) is a soluble Wnt antagonist with established roles in skeletal development, however, its specific function in myogenesis remains underexplored. This study investigated the regulatory role of FRZB in muscle development, hypothesizing that it contributes to breed-specific growth differences in pigs. We examined FRZB expression in fetal tissues of slow-growing (Tibetan and Wujin) and fast-growing (Large White) pigs, and assessed its function in C2C12 myoblasts via siRNA-mediated knockdown. FRZB was widely expressed across porcine fetal tissues, with significantly higher abundance in the longissimus dorsi of slow-growing breeds. In vitro, FRZB silencing significantly enhanced myoblast proliferation and migration. Furthermore, knockdown accelerated differentiation and promoted the formation of longer, thicker multinucleated myotubes, accompanied by the upregulation of myogenic (MyoD, MyoG, MyHC) and fusion (β1-integrin, Myomaker) markers. Transcriptional profiling revealed a shift toward hypertrophy (Fst and Nog upregulation) and away from atrophy (Atrogin1 downregulation). These findings identify FRZB as a negative regulator of myogenesis via the Wnt signaling pathway. The elevated expression in indigenous breeds suggests FRZB may impose a molecular constraint on muscle development, highlighting its potential as a candidate gene for regulating carcass traits.