MiR-29a Family as a Key Regulator of Skeletal Muscle Dysplasia in a Porcine Model of Intrauterine Growth Retardation

MUSTN1 Interaction With SMPX Regulates Muscle Development and Regeneration

Pigs are important agricultural animals whose growth rate and meat production performance are related to muscle development. Musculoskeletal embryonic nuclear protein 1 (MUSTN1) participates in various biological processes, including myogenesis and growth in animals, but the physiological functions and mechanisms of porcine MUSTN1 on muscle development are unclear; thus, we aimed to elucidate them. We found that MUSTN1 was highly expressed in the muscles of fast-growing pigs. Functionally, MUSTN1 promoted myoblast proliferation and differentiation. MUSTN1 knockout mice exhibited reduced muscle mass and fibre cross-sectional area, decreased exercise endurance, and delayed muscle regeneration. Small muscle protein X-linked (SMPX) was identified as an interacting protein of MUSTN1, and its promotion of myogenic differentiation depended on MUSTN1. Furthermore, MUSTN1 stabilised SMPX and maintained myofiber morphology. This study suggests that MUSTN1 is a critical regulator in the control of muscle development and regeneration and is a potential target for animal genetic improvement and the treatment of human muscle disease.

Exosomal miRNAs in prenatal diagnosis: Recent advances

Exosomes, small membranous microvesicles released by cells, contain a range of bioactive molecules, including proteins and miRNAs, which play critical roles in intercellular communication and physiological and pathological processes. Current research suggests that exosomal miRNAs could serve as valuable biomarkers for prenatal diseases, offering a noninvasive method for early detection and monitoring. Studies linking exosomal miRNAs to various birth defects, including fetal growth restriction, urinary tract malformations, cardiovascular system malformations, and hereditary diseases like Down syndrome, were discussed. However, there are some conflicting study findings due to different exosome separation methods. Here, we also discussed exosome separation methods, emphasizing the importance of method selection based on specific purposes and sample types. Further studies are needed to standardize isolation techniques, understand the specific mechanisms underlying exosomal miRNA function, and develop reliable noninvasive prenatal diagnostic indicators. Overall, exosomal miRNAs show promise as potential biomarkers for prenatal diagnosis, but further research is necessary to validate their clinical utility.

tRNA-derived small RNA dataset in multiple organs of intrauterine growth-restricted pig

Intrauterine growth restriction (IUGR) impairs neonatal weight and causes multiple organ dysplasia. IUGR not only threatens human health but is also a significant constraint to the development of animal husbandry. However, the molecular mechanism underlying IUGR remains to be further elucidated. tRNA-derived small RNA (tsRNAs) is a regulative non-coding RNA, which has recently been reported to correlate with the onset and progression of several diseases. In this study, we investigated the tsRNAs expression profiles of IUGR pigs. A tsRNAs dataset for multiple organs in normal and IUGR pigs was generated, including muscle, liver, spleen and intestine. We further analyzed the characteristics of tsRNAs in different organs of pigs, and KEGG pathway analysis was performed to investigate possible pathways involved. This dataset will provide valuable information for further exploring the molecular mechanism of IUGR formation.

Characteristics of microRNAs in Skeletal Muscle of Intrauterine Growth-Restricted Pigs

microRNAs are a class of small RNAs that have been extensively studied, which are involved in many biological processes and disease occurrence. The incidence of intrauterine growth restriction is higher in mammals, especially multiparous mammals. In this study, we found that the weight of the longissimus dorsi of intrauterine growth-restricted pigs was significantly lower than that of normal pigs. Then, intrauterine growth-restricted pig longissimus dorsi were used to characterize miRNA expression profiles by RNA sequencing. A total of 333 miRNAs were identified, of which 26 were differentially expressed. Functional enrichment analysis showed that these differentially expressed miRNAs regulate the expression of their target genes (such as PIK3R1, CCND2, AKT3, and MAP3K7), and these target genes play an important role in the proliferation and differentiation of skeletal muscle through signaling pathways such as the PI3K-Akt, MAPK, and FoxO signaling pathways. Furthermore, miRNA-451 was significantly upregulated in IUGR pig skeletal muscle. Overexpression of miR-451 in C2C12 cells significantly promoted the expression of Mb, Myod, Myog, Myh1, and Myh7, suggesting that miR-451 may be involved in the regulation of the myoblastic differentiation of C2C12 cells. Our results reveal the role of miRNA-451 in regulating myogenic differentiation of skeletal muscle in pigs with intrauterine growth restriction.

Identification of tRNA-derived small RNAs and their potential roles in porcine skeletal muscle with intrauterine growth restriction

Intrauterine growth restriction (IUGR) in humans often manifests as poor growth and delayed intellectual development, whereas in domestic animals it results in increased mortality. As a novel epigenetic regulatory molecule, tRNA-derived small RNAs (tsRNAs) have been reported to be involved in many biological processes. In this study, pigs (35d) were used as a model to characterize tsRNAs by sequencing in normal and IUGR porcine skeletal muscle. A total of 586 tsRNAs were identified, of which 103 were specifically expressed in normal-size pigs and 38 were specifically expressed in IUGR pigs. The tsRNAs formed by splicing before the 5' end anti codon of mature tRNA (tRF-5c) accounted for over 90% of tsRNAs, which were significantly enriched in IUGR pigs than in normal-size pigs. Enriched pathways of differentially expressed tsRNAs target genes mainly included metabolic pathways, Rap1 signaling pathway, endocytosis, mTOR signaling pathway, and AMPK signaling pathway. Regulatory network analysis of target genes revealed that IGF1 was one of the most important molecules of regulatory nodes in IUGR and normal porcine skeletal muscle. In addition, IGF1 was found to be one of the target genes of tRF-Glu-TTC-047, which is a highly expressed tsRNA in IUGR pigs. The findings described herein uncover the role of tsRNAs in IUGR porcine skeletal muscle development, thus providing insights into the prevention and treatment of IUGR in mammals.