Lysine inhibits apoptosis in satellite cells to govern skeletal muscle growth via the JAK2-STAT3 pathway

Effects of rumen metabolite butyric acid on bovine skeletal muscle satellite cells proliferation, apoptosis and transcriptional states during myogenic differentiation

Butyric acid, a pivotal short-chain fatty acid in rumen digestion, profoundly influences animal digestive and locomotor systems. Extensive research indicates its direct or indirect involvement in the growth and development of muscle and fat cells. However, the impact of butyric acid on the proliferation and differentiation of bovine skeletal muscle satellite cells (SMSCs) remains unclear. This study aimed to elucidate the effects of butyrate on SMSCs proliferation and differentiation. After isolating, SMSCs were subjected to varying concentrations of sodium butyrate (NaB) during the proliferation and differentiation stages. Optimal treatment conditions (1 mM NaB for 2 days) were determined based on proliferative force, cell viability, and mRNA expression of proliferation and differentiation marker genes. Transcriptome sequencing was employed to screen for differential gene expression between 1 mM NaB-treated and untreated groups during SMSCs differentiation. Results indicated that lower NaB concentrations (≤1.0 mM) inhibited proliferation while promoting differentiation and apoptosis after a 2-day treatment. Conversely, higher NaB concentrations (≥2.0 mM) suppressed proliferation and differentiation and induced apoptosis. Transcriptome sequencing revealed differential expression of genes(ND1, ND3, CYTB, COX2, ATP6, MYOZ2, MYOZ3, MYBPC1 and ATP6V0A4,etc.) were associated with SMSCs differentiation and energy metabolism, enriching pathways such as Oxidative phosphorylation, MAPK, and Wnt signaling. These findings offer valuable insights into the molecular mechanisms underlying butyrate regulation of bovine SMSCs proliferation and differentiation, as well as muscle fiber type conversion in the future study.

Identification of key genes and signaling pathways based on transcriptomic studies of aerobic and resistance training interventions in sarcopenia in SAMP8 mice

We examined the effects of resistance and aerobic exercise on the gene expression and biometabolic processes of aging skeletal muscle in senescence-accelerated mouse/prone 8 mice, a model of sarcopenia, and compared them with senescence-accelerated mouse/resistant 1 mice acting as controls. We found that exercise improved muscle strength, endurance, fiber size, also modulated genes and pathways related to synaptic transmission, potassium transport, JAK-STAT signaling, and PI3K-Akt signaling. Our results suggested that BDNF, JAK2, RhoC, Myh6, Stat5a, Tnnc1, and other genes may mediate the beneficial effects of exercise on sarcopenia through these pathways.

Effect of glucose and lysine supplementation on myogenic and adipogenic gene expression in muscle satellite cells isolated from Hanwoo with different genotypes of PLAG1: Implications for cell-based food production

Research on Hanwoo cattle has focused on the pleomorphic adenoma gene (PLAG) family, vital for traits like growth and carcass quality. Single nucleotide polymorphisms (SNPs) within this gene family profoundly impact economic traits. At the cellular level, energy and protein sources, notably glucose and lysine, crucially regulate muscle satellite cell (MSC) growth and differentiation. This study delved into how varied glucose and lysine levels affect gene expression patterns in Hanwoo MSC. MSC from 9 Hanwoo, aged 29-36 months, categorized into 3 PLAG1 genotypes (GG, GC, CC), were treated with six combinations of glucose (5.5 and 25 mM) and lysine (2, 4, and 8 mM). Analysis of myogenic and adipogenic genes linked to meat quality and quantity ensued. The GG genotype displayed superior dressed percentage, yield grade, and marbling score, hinting at genotype-associated carcass characteristic disparities. In cell culture, gene expression generally rose with lysine addition to high glucose in the GG group. Contrarily, significant differences across all treatments in the GC genotype suggested distinct responses. Significant effects of genotype, glucose, and lysine on cell proliferation-related gene expression were noted. Highest mRNA expression for MyoD, MyoG, and FASN occurred in the CC genotype, while Myf5 and Pax7 expression peaked in the GG genotype. Glucose significantly influenced Pax7 and FASN expression, while lysine positively impacted MyoD and MyoG genes. Notable interactions, especially in Genotype × Lysine, influenced MyoD, Myf5, and Pax7 expression, highlighting complex relationships in cell proliferation. Regarding cell differentiation, Pax7 expression was highest in PLAG1 GG type. High glucose prompted wider myotubes, while lower lysine concentrations slightly favored cell differentiation. Correspondingly, MyoG expression decreased with higher lysine levels. This study furnishes insights into lysine and glucose supplementation effects on bovine MSC proliferation and differentiation, considering PLAG1 genotype influence. It offers valuable data for beef production system establishment and optimizing cell-based food production.

Analysis of PANoptosis-related ceRNA network reveals lncRNA MIR17HG involved in osteogenic differentiation inhibition impaired by tumor necrosis factor-α

BACKGROUND

Inflammatory cytokines such as Interleukin 1β(IL1β), IL6,Tumor Necrosis Factor-α (TNF-α) can inhibit osteoblast differentiation and induce osteoblast apoptosis. PANoptosis, a newly identified type of programmed cell death (PCD), may be influenced by long noncoding RNA (lncRNAs) which play important roles in regulating inflammation. However, the potential role of lncRNAs in inflammation and PANoptosis during osteogenic differentiation remains unclear. This study aimed to investigate the regulatory functions of lncRNAs in inflammation and apoptosis during osteogenic differentiation.

METHODS AND RESULTS

High-throughput sequencing was used to identify differentially expressed genes involved in osteoblast differentiation under inflammatory conditions. Two lncRNAs associated with inflammation and PANoptosis during osteogenic differentiation were identified from sequencing data and Gene Expression Omnibus (GEO) databases. Their functionalities were analyzed using diverse bioinformatics methodologies, resulting in the construction of the lncRNA-miRNA-mRNA network. Among these, lncRNA (MIR17HG) showed a high correlation with PANoptosis. Bibliometric methods were employed to collect literature data on PANoptosis, and its components were inferred. PCR and Western Blotting experiments confirmed that lncRNA MIR17HG is related to PANoptosis in osteoblasts during inflammation.

CONCLUSIONS

Our data suggest that TNF-α-induced inhibition of osteogenic differentiation and PANoptosis in MC3T3-E1 osteoblasts is associated with MIR17HG. These findings highlight the critical role of MIR17HG in the interplay between inflammation, PANoptosis, and osteogenic differentiation, suggesting potential therapeutic targets for conditions involving impaired bone formation and inflammatory responses.

Relationship between Indel Variants within the JAK2 Gene and Growth Traits in Goats

Janus kinase 2 (JAK2) plays a critical role in myoblast proliferation and fat deposition in animals. Our previous RNA-Seq analyses identified a close association between the JAK2 gene and muscle development. To date, research delving into the relationship between the JAK2 gene and growth traits has been sparse. In this study, we sought to investigate the relationship between novel mutations within the JAK2 gene and goat growth traits. Herein, two novel InDel (Insertion/Deletion) polymorphisms within the JAK2 gene were detected in 548 goats, and only two genotypes were designated as ID (Insertion/Deletion) and DD (Deletion/Deletion). The results indicate that the two InDels, the del19008 locus in intron 2 and del72416 InDel in intron 6, showed significant associations with growth traits (p < 0.05). Compared to Nubian and Jianzhou Daer goats, the del72416 locus displayed a more pronounced effect in the Fuqing breed group. In the Nubian breed (NB) group, both InDels showed a marked influence on body height (BH). There were strong linkages observed for these two InDels between the Fuqing (FQ) and Jianzhou (JZ) populations. The DD-ID diplotype was associated with inferior growth traits in chest width (ChW) and cannon circumference (CaC) in the FQ goats compared to the other diplotypes. In the NB population, the DD-DD diplotype exhibited a marked negative impact on BH and HuWI (hucklebone width index), in contrast to the other diplotypes. In summary, our findings suggest that the two InDel polymorphisms within the JAK2 gene could serve as valuable molecular markers for enhancing goat growth traits in breeding programs.

Preclinical development and clinical studies of targeted JAK/STAT combined Anti-PD-1/PD-L1 therapy

Programmed cell death protein 1 (PD-1) binds to its ligand to help tumours evade the immune system and promote tumour progression. Although anti-PD-1/PD-L1 therapies show powerful effects in some patients, most patients are unable to benefit from this treatment due to treatment resistance. Therefore, it is important to overcome tumour resistance to PD-1/PD-L1 blockade. There is substantial evidence suggesting that the JAK/STAT signalling pathway plays a significant role in PD-1/PD-L1 expression and anti-PD-1/PD-L1 treatment. Herein, we describe the effects of the JAK/STAT signalling pathway on PD-1/PD-L1. Subsequently, the relationship between molecular mutations in the JAK/STAT signalling pathway and immune resistance was analysed. Finally, the latest advancements in drugs targeting the JAK/STAT pathway combined with PD1/PD-L1 inhibitors are summarised.

Selenoprotein K knockdown induces apoptosis in skeletal muscle satellite cells via calcium dyshomeostasis-mediated endoplasmic reticulum stress

Skeletal muscle satellite cells (SMSCs), known as muscle stem cells, play an important role in muscle embryonic development, post-birth growth, and regeneration after injury. Selenoprotein K (SELENOK), an endoplasmic reticulum (ER) resident selenoprotein, is known to regulate calcium ion (Ca2+) flux and ER stress (ERS). SELENOK deficiency is involved in dietary selenium deficiency-induced muscle injury, but the regulatory mechanisms of SELENOK in SMSCs development remain poorly explored in chicken. Here, we established a SELENOK deficient model to explore the role of SELENOK in SMSCs. SELENOK knockdown inhibited SMSCs proliferation and differentiation by regulating the protein levels of paired box 7 (Pax7), myogenic factor 5 (Myf5), CyclinD1, myogenic differentiation (MyoD), and Myf6. Further analysis exhibited that SELENOK knockdown markedly activated the ERS signaling pathways, which ultimately induced apoptosis in SMSCs. SELENOK knockdown-induced ERS is related with ER Ca2+ ([Ca2+]ER) overload via decreasing the protein levels of STIM2, Orai1, palmitoylation of inositol 1,4,5-trisphosphate receptor 1 (IP3R1), phospholamban (PLN), and plasma membrane Ca2+-ATPase (PMCA) while increasing the protein levels of sarco/endoplasmic Ca2+-ATPase 1 (SERCA1) and Na+/Ca2+ exchanger 1 (NCX1). Moreover, thimerosal, an activator of IP3R1, reversed the overload of [Ca2+]ER, ERS, and subsequent apoptosis caused by SELENOK knockdown. These findings indicated that SELENOK knockdown triggered ERS driven by intracellular Ca2+ dyshomeostasis and further induced apoptosis, which ultimately inhibited SMSCs proliferation and differentiation.

Transcriptome Sequencing Analysis of circRNA in Skeletal Muscle between Fast- and Slow-Growing Chickens at Embryonic Stages

Skeletal muscle growth has always been the focus of the broiler industry, and circRNAs play a significant role in this process. We collected leg muscles of slow- and fast-growing Bian chicken embryos in the study at 14 (S14 and F14) and 20 (S20 and F20) days for RNA-seq. Finally, 123 and 121 differentially expressed circRNAs (DECs) were identified in S14 vs. F14 and S20 vs. F20, respectively. GO enrichment analysis for DECs obtained important biological process (BP) terms including nicotinate nucleotide biosynthetic process, nicotinate nucleotide salvage, and NAD salvage in S20 vs. F20 and protein mannosylation in S14 vs. F14. KEGG pathway analysis showed Wnt signaling pathway, Tight junction, Ubiquitin mediated proteolysis, and Notch signaling pathway were enriched in the top 20. Based on the GO and KEGG analysis results, we found some significant host genes and circRNAs such as NAPRT and novel_circ_0004547, DVL1 and novel_circ_0003578, JAK2 and novel_circ_0010289, DERA and novel_circ_0003082, etc. Further analysis found 19 co-differentially expressed circRNAs between the two comparison groups. We next constructed a circRNA-miRNA network for them, and some candidate circRNA-miRNA pairs related to skeletal muscle were obtained, such as novel_circ_0002153-miR-12219-5p, novel_circ_0003578-miR-3064-3p, and novel_circ_0010661-miR-12260-3p. These results would help to reveal the mechanism for circRNAs in skeletal muscle and also provide some guidance for the breeding of broilers.

mTORC1 Mediates the Processes of Lysine Regulating Satellite Cells Proliferation, Apoptosis, and Autophagy

Lysine (Lys) is essential for skeletal muscle growth and protein synthesis in mammals. However, the regulatory network underlying Lys-regulated skeletal muscle development is unknown. To determine whether any cross-talk occurs among mammalian targets of rapamycin complex 1 (mTORC1) and Lys in the regulation of muscle satellite cells (SCs) proliferation, we applied the treatment rapamycin (a mTORC1 inhibitor) and MHY1485 (a mTORC1 activator) on Lys-added or -deficient SCs. The results show Lys deprivation significantly decreases SCs viability, protein synthesis, and cell cycling, increases autophagy and apoptosis, and inhibits the mTORC1 signaling pathway. Restoration of Lys content significantly attenuates this effect. mTORC1 signaling pathway activation during Lys deprivation or mTORC1 signaling pathway inhibition during Lys addition attenuates the effect of Lys deprivation or addition on SCs viability, protein synthesis, cell cycling, autophagy, and apoptosis. In conclusion, Lys could improve SCs proliferation, and inhibit SCs apoptosis and autophagy, via the mTORC1 signaling pathway.

Changes of Gene Expression Patterns of Muscle Pathophysiology-Related Transcription Factors During Denervated Muscle Atrophy

Peripheral nerve injury is common, and can lead to skeletal muscle atrophy and dysfunction. However, the underlying molecular mechanisms are not fully understood. The transcription factors have been proved to play a key role in denervated muscle atrophy. In order to systematically analyze transcription factors and obtain more comprehensive information of the molecular regulatory mechanisms in denervated muscle atrophy, a new transcriptome survey focused on transcription factors are warranted. In the current study, we used microarray to identify and analyze differentially expressed genes encoding transcription factors in denervated muscle atrophy in a rat model of sciatic nerve dissection. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to explore the biological functions of differentially expressed transcription factors and their target genes related to skeletal muscle pathophysiology. We found that the differentially expressed transcription factors were mainly involved in the immune response. Based on correlation analysis and the expression trends of transcription factors, 18 differentially expressed transcription factors were identified. Stat3, Myod1, Runx1, Atf3, Junb, Runx2, Myf6, Stat5a, Tead4, Klf5, Myog, Mef2a, and Hes6 were upregulated. Ppargc1a, Nr4a1, Lhx2, Ppara, and Rxrg were downregulated. Functional network mapping revealed that these transcription factors are mainly involved in inflammation, development, aging, proteolysis, differentiation, regeneration, autophagy, oxidative stress, atrophy, and ubiquitination. These findings may help understand the regulatory mechanisms of denervated muscle atrophy and provide potential targets for future therapeutic interventions for muscle atrophy following peripheral nerve injury.

Aerobic Exercise Improves Type 2 Diabetes Mellitus-Related Cognitive Impairment by Inhibiting JAK2/STAT3 and Enhancing AMPK/SIRT1 Pathways in Mice

Type 2 diabetes mellitus (T2DM) is a prevalent risk factor for cognitive impairment. Aerobic exercise can improve T2DM-related cognitive impairment; however, the possible mechanisms remain elusive. Thus, we assessed db/m mice and leptin receptor-deficient (db/db) mice that did or did not perform aerobic exercise (8 m/min, 60 min/day, and 5 days/week for 12 weeks). In this study, cognitive function was significantly impaired in the T2DM mice; aerobic exercise improved cognitive impairment through activating the AMPK/SIRT1 signalling pathway and inhibiting the JAK2/STAT3 signalling pathway in T2DM mice. However, after the application of RO8191 (JAK2 activator) or Compound C (AMPK inhibitor), the positive improvement of the exercise was evidently suppressed. Taken together, our data indicated that long-term aerobic exercise improves type 2 diabetes mellitus-related cognitive impairment by inhibiting JAK2/STAT3 and enhancing AMPK/SIRT1 pathways in mice.

Satellite Cells Exhibit Decreased Numbers and Impaired Functions on Single Myofibers Isolated from Vitamin B6-Deficient Mice

Emerging research in human studies suggests an association among vitamin B6, sarcopenia, and muscle strength. However, very little is known regarding its potential role at the cellular level, especially in muscle satellite cells. Therefore, to determine whether vitamin B6 affects the satellite cells, we isolated single myofibers from muscles of vitamin B6-deficient and vitamin B6-supplemented mice. Subsequently, we subjected them to single myofiber culture and observed the number and function of the satellite cells, which remained in their niche on the myofibers. Prior to culture, the vitamin B6-deficient myofibers exhibited a significantly lower number of quiescent satellite cells, as compared to that in the vitamin B6-supplemented myofibers, thereby suggesting that vitamin B6 deficiency induces a decline in the quiescent satellite cell pool in mouse muscles. After 48 and 72 h of culture, the number of proliferating satellite cells per cluster was similar between the vitamin B6-deficient and -supplemented myofibers, but their numbers decreased significantly after culturing the myofibers in vitamin B6-free medium. After 72 h of culture, the number of self-renewing satellite cells per cluster was significantly lower in the vitamin B6-deficient myofibers, and the vitamin B6-free medium further decreased this number. In conclusion, vitamin B6 deficiency appears to reduce the number of quiescent satellite cells and suppress the proliferation and self-renewal of satellite cells during myogenesis.

Lycopene Protects Intestinal Epithelium from Deoxynivalenol-Induced Oxidative Damage via Regulating Keap1/Nrf2 Signaling

Deoxynivalenol (DON) is a threatening mycotoxin primarily present in the agricultural environment, especially in food commodities and animal forages, and exerts significant global health hazards. Lycopene (LYC) is a potent antioxidant carotenoid mainly present in tomatoes and other fruits with enormous health benefits. The present study was designed to ascertain whether LYC could protect DON-induced intestinal epithelium oxidative injury by regulating Keap1/Nrf2 signaling in the intestine of mice. A total of forty-eight mice were randomly distributed into four groups (n = 12), Control (CON), 10 mg/kg BW LYC, 3 mg/kg BW DON, and 3 mg/kg DON + 10 mg/kg LYC BW (DON + LYC). The experimental groups were treated by intragastric administration for 11 days. Our results showed that LYC significantly increased average daily feed intake (ADFI), average daily gain (ADG), and repaired intestinal injury and barrier dysfunction, as evident by increased trans-epithelial electrical resistance (TEER) and decreased diamine oxidase (DAO) activity, as well as up-regulated tight junction proteins (occludin, claudin-1) under DON exposure. Furthermore, LYC treatment stabilized the functions of intestinal epithelial cells (Lgr5, PCNA, MUC2, LYZ, and Villin) under DON exposure. Additionally, LYC alleviated DON-induced oxidative stress by reducing ROS and MDA accumulation and enhancing the activity of antioxidant enzymes (CAT, T-SOD, T-AOC, and GSH-Px), which was linked with the activation of Nrf2 signaling and degradation of Keap1 expression. Conclusively, our findings demonstrated that LYC protects intestinal epithelium from oxidative injury by modulating the Keap1/Nrf2 signaling pathway under DON exposure. These novel findings could lead to future research into the therapeutic use of LYC to protect the DON-induced harmful effects in humans and/or animals.

Methionine promotes crop milk protein synthesis through the JAK2-STAT5 signaling during lactation of domestic pigeons (Columba livia)

Crop milk is the sole source of nutrition that sustains young pigeons (squabs) throughout growth and development. Protein accounts for approximately 55% of the nutrients in crop milk; however, its regulation mechanism remains unclear. In our study, three experiments were conducted to investigate the possible underlying mechanism of crop milk protein synthesis and nutritional interventions. Isobaric tagging for relative and absolute quantification (iTRAQ) analysis found that the Janus activated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway was significantly up-regulated in breeding pigeons during lactation compared to non-breeding pigeons. Moreover, the serum prolactin (PRL) levels increased, and the protein expression of the PRL receptor (PRLR)/JAK2/STAT5 pathway was significantly up-regulated during lactation. The serum PRL, the PRLR/JAK2/STAT5 pathway, the crop milk protein synthesis, and the squab growth performance were inhibited by bromocriptine mesylate injection, a PRL-specific inhibitor. In addition, dietary supplementation with 0.30% dl-methionine or dl-methionine-dl-methionine (especially 0.30% dl-methionine-dl-methionine), significantly increased serum PRL levels and PRLR/JAK2/STAT5 activity, and improved the crop milk protein synthesis. In conclusion, our results demonstrated that the PRL-induced PRLR/JAK2/STAT5 signaling pathway plays a vital regulatory role in crop milk protein synthesis, and 0.30% dl-methionine-dl-methionine is superior to dl-methionine in promoting crop milk protein synthesis.