Resveratrol regulates muscle fiber type gene expression through AMPK signaling pathway and miR-22-3p in porcine myotubes

Candidate circRNAs related to skeletal muscle development in Dazu black goats

Circular RNA (CircRNA), as a classical noncoding RNA, has been proven to regulate skeletal muscle development (SMD). However, the molecular genetic basis of circRNA regulation in muscle cells remains unclear. In this study, the expression patterns of circRNAs in the longissimus dorsi muscle at embryonic day 75 and postnatal day 1 in DBGs were investigated to identify the key circRNAs that play an important role in SMD in goats. A total of 140 significantly and differentially expressed circRNAs (DEcircRNAs) were identified among the groups at different developmental stages. Among the 116 host genes (HGs) of DEcircRNAs, 76 were significantly and differentially expressed, which was confirmed by previous RNA_seq data. Furthermore, the expression pattern of 10 DEcircRNAs with RT-qPCR was verified, which showed 80% concordance rate with that of RNA_seq datasets. Moreover, the authenticity of seven randomly selected DEcircRNAs was verified by PCR Sanger sequencing. Based on the functional annotation results, among the 76 significantly and differentially expressed HGs, 74 were enriched in 845 GO terms, whereas 35 were annotated to 85 KEGG pathways. The results of this study could provide a comprehensive understanding of the genetic basis of circRNAs involved in SMD and muscle growth.

Neonatal resveratrol treatment in cerebral palsy model recovers neurodevelopment impairments by restoring the skeletal muscle morphology and decreases microglial activation in the cerebellum

Cerebral Palsy (CP) is the main motor disorder in childhood resulting from damage to the developing brain. Treatment perspectives are required to reverse the primary damage caused by the early insult and consequently to recover motor skills. Resveratrol has been shown to act as neuroprotection with benefits to skeletal muscle. This study aimed to investigate the effects of neonatal resveratrol treatment on neurodevelopment, skeletal muscle morphology, and cerebellar damage in CP model. Wistar rat pups were allocated to four experimental groups (n = 15/group) according CP model and treatment: Control+Saline (CS), Control+Resveratrol (CR), CP + Saline (CPS), and CP + Resveratrol (CPR). CP model associated anoxia and sensorimotor restriction. CP group showed delay in the disappearance of the palmar grasp reflex (p < 0.0001) and delay in the appearance of reflexes of negative geotaxis (p = 0.01), and free-fall righting (p < 0.0001), reduced locomotor activity and motor coordination (p < 0.05) than CS group. These motor skills impairments were associated with a reduction in muscle weight (p < 0.001) and area and perimeter of soleus end extensor digitorum longus muscle fibers (p < 0.0001), changes in muscle fibers typing pattern (p < 0.05), and the cerebellum showed signs of neuroinflammation due to elevated density and percentage of activated microglia in the CPS group compared to CS group (p < 0.05). CP animals treated with resveratrol showed anticipation of the appearance of negative geotaxis and free-fall righting reflexes (p < 0.01), increased locomotor activity (p < 0.05), recovery muscle fiber types pattern (p < 0.05), and reversal of the increase in density and the percentage of activated microglia in the cerebellum (p < 0.01). Thus, we conclude that neonatal treatment with resveratrol can contribute to the recovery of the delay neurodevelopment resulting from experimental CP due to its action in restoring the skeletal muscle morphology and reducing neuroinflammation from cerebellum.

Research Progress on the Regulating Factors of Muscle Fiber Heterogeneity in Livestock: A Review

The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity.

Effect of resveratrol on skeletal slow-twitch muscle fiber expression via AMPK/PGC-1α signaling pathway in bovine myotubes

The purpose of this study was to evaluate the impact of resveratrol on slow-twitch muscle fiber expression in bovine myotubes. The results revealed that resveratrol enhanced slow myosin heavy chain (MyHC) and suppressed fast MyHC protein expression, accompanied by increased MyHC I/IIa and decreased MyHC IIx/IIb mRNA levels in bovine myotubes (P < 0.05). Resveratrol also enhanced the activities of succinic dehydrogenase (SDH), malate dehydrogenase (MDH) and the mitochondrial DNA (mtDNA) content, but reduced lactate dehydrogenase (LDH) activity (P < 0.05). Meanwhile, the protein and gene expression of AMPK, SIRT1 and PGC-1α were upregulated by resveratrol (P < 0.05). Furthermore, PGC-1α inhibitor SR-18292 could attenuate resveratrol-induced muscle fiber conversion from fast-twitch to slow-twitch. These results suggest that resveratrol might promote muscle fiber type transition from fast-twitch to slow-twitch through the AMPK/PGC-1α signaling pathway and mitochondrial biogenesis in bovine myotubes.

A polymorphism in porcine miR-22 is associated with pork color

MicroRNAs (miRNAs) are posttranscriptional regulators that play key roles in meat color regulation. Changes in miRNA expression affect their target mRNAs, leading to multifunctional effects on biological processes and phenotypes. In this study, a G > A mutation site located upstream of the precursor miR-22 sequence in Suhuai pigs was significantly correlated with the meat color parameter a^*(redness) of the porcine longissimus dorsi (LD) muscle. AA genotype individuals had the highest average meat color a^* value and the lowest miR-22 level. When G > A mutation was performed in the miR-22 overexpression vector, miR-22 expression significantly decreased. Considering that Ca²⁺ homeostasis is closely related to pig meat color, our results further demonstrated that ELOVL6 is a direct target of miR-22 in pigs. The effects of miR-22 on skeletal muscle intracellular Ca²⁺ were partially caused by the suppression of ELOVL6 expression.