Inhibits Myoblast Differentiation Research Articles

OTUB1 regulates ferroptosis to inhibit myoblast differentiation into myotubes by deubiquitinating P62

As the largest organ in the human body, skeletal muscle is essential for breathing support, movement initiation, and maintenance homeostasis. It has been shown that programmed cell death (PCD), which includes autophagy, apoptosis, and necrosis, is essential for the development of skeletal muscle. A novel form of PCD called ferroptosis is still poorly understood in relation to skeletal muscle. In this study, we observed that the activation of ferroptosis significantly impeded the differentiation of C2C12 myoblasts into myotubes and concurrently suppressed the expression of OTUB1, a crucial deubiquitinating enzyme. OTUB1-silenced C2C12 mouse myoblasts were used to investigate the function of OTUB1 in ferroptosis. The results show that OTUB1 knockdown in vitro significantly increased C2C12 ferroptosis and inhibited myogenesis. Interestingly, the induction of ferroptosis resulting from OTUB1 knockdown was concomitant with the activation of autophagy. Furthermore, OTUB1 interacted with the P62 protein and stabilized its expression by deubiquitinating it, thereby inhibiting autophagy-dependent ferroptosis and promoting myogenesis. All of these findings demonstrate the critical role that OTUB1 plays in controlling ferroptosis, and we suggest that focusing on the OTUB1-P62 axis may be a useful tactic in the treatment and prevention of disorders involving the skeletal muscle.

Targeting specific DNA G-quadruplexes with CRISPR-guided G-quadruplex-binding proteins and ligands.

Despite the demonstrated importance of DNA G-quadruplexes (G4s) in health and disease, technologies to readily manipulate specific G4 folding for functional analysis and therapeutic purposes are lacking. Here we employ G4-stabilizing protein/ligand in conjunction with CRISPR to selectively facilitate single or multiple targeted G4 folding within specific genomic loci. We demonstrate that fusion of nucleolin with a catalytically inactive Cas9 can specifically stabilize G4s in the promoter of oncogene MYC and muscle-associated gene Itga7 as well as telomere G4s, leading to cell proliferation arrest, inhibition of myoblast differentiation and cell senescence, respectively. Furthermore, CRISPR can confer intra-G4 selectivity to G4-binding compounds pyridodicarboxamide and pyridostatin. Compared with traditional G4 ligands, CRISPR-guided biotin-conjugated pyridodicarboxamide enables a more precise investigation into the biological functionality of de novo G4s. Our study provides insights that will enhance understanding of G4 functions and therapeutic interventions.

Endothelin-1 impairs skeletal muscle myogenesis and development via ETB receptors and p38 MAPK signaling pathway.

Myopenia is a condition marked by progressive decline of muscle mass and strength and is associated with aging or obesity. It poses the risk of falling, with potential bone fractures, thereby also increasing the burden on family and society. Skeletal muscle wasting is characterized by a reduced number of myoblasts, impaired muscle regeneration and increased muscle atrophy markers (Atrogin-1, MuRF-1). Endotheline-1 (ET-1) is a potent vasoconstrictor peptide. Increased circulating levels of ET-1 is noted with aging and is associated with muscular fibrosis and decline of strength. However, the regulatory mechanism controlling its effect on myogenesis and atrophy remains unknown. In the present study, the effects of ET-1 on myoblast proliferation, differentiation and development were investigated in C2C12 cells and in ET-1-infused mice. The results show that ET-1, acting via ETB receptors, reduced insulin-stimulated cell proliferation, and also reduced MyoD, MyoG and MyHC expression in the differentiation processes of C2C12 myoblasts. ET-1 inhibited myoblast differentiation through ETB receptors and the p38 mitogen-activated protein kinase (MAPK)-dependent pathway. Additionally, ET-1 decreased MyHC expression in differentiated myotubes. Inhibition of proteasome activity by MG132 ameliorated the ET-1-stimulated protein degradation in differentiated C2C12 myotubes. Furthermore, chronic ET-1 infusion caused skeletal muscle atrophy and impaired exercise performance in mice. In conclusion, ET-1 inhibits insulin-induced cell proliferation, impairs myogenesis and induces muscle atrophy via ETB receptors and the p38 MAPK-dependent pathway.

Macrophage scavenger receptor-A1 promotes skeletal muscle regeneration after hindlimb ischemia.

Macrophages mediated inflammatory response is crucial for the recovery of skeletal muscle following ischemia. Thus, it's necessary to exploit macrophages based therapeutic targets for ischemic disease. Here, we found mRNA level of SR-A1 was elevated in patients with critical limb ischemia by analysis of gene expression omnibus (GEO) database. Then we investigated the role and the underlined mechanisms of macrophage SR-A1 in a mouse HLI model. Compared with the SR-A1 fl/fl mice, the Lyz Cre/+/SR-A1 flox/flox (SR-A1 ΔMΦ) mice showed significantly lower laser doppler blood flow in the ischemic limb at day 7 after HLI. Consistently, histological analysis exhibited that ischemic limb of SR-A1 ΔMΦ mice displayed more sever and sustained necrotic morphology, inflammation and fibrosis, decreased vessel density and regeneration rate, compared with which of control SR-A1 fl/fl mice. Furthermore, restoration of wild-type myeloid cells to SR-A1 knock-out mice effectively relieved the doppler perfusion in the ischemic limb and restrained skeletal muscle damage 7 days post HLI. In line with in vivo findings, when co-cultivating macrophages with the mouse myoblast line C2C12, SR-A1 -/- bone marrow macrophage significantly inhibited myoblast differentiation in vitro. Mechanically, SR-A1 enhanced skeletal muscle regeneration response to HLI by inhibiting the oncostatin M (OSM) production via suppressed NF-κB signaling activation. These results indicates that SR-A1 is a promising candidate molecule to improve tissue repair and regeneration in peripheral ischemic arterial disease.

Chromatin profiling reveals TFAP4 as a critical transcriptional regulator of bovine satellite cell differentiation

BackgroundSatellite cells are myogenic precursor cells in adult skeletal muscle and play a crucial role in skeletal muscle regeneration, maintenance, and growth. Like embryonic myoblasts, satellite cells have the ability to proliferate, differentiate, and fuse to form multinucleated myofibers. In this study, we aimed to identify additional transcription factors that control gene expression during bovine satellite cell proliferation and differentiation.ResultsUsing chromatin immunoprecipitation followed by sequencing, we identified 56,973 and 54,470 genomic regions marked with both the histone modifications H3K4me1 and H3K27ac, which were considered active enhancers, and 50,956 and 59,174 genomic regions marked with H3K27me3, which were considered repressed enhancers, in proliferating and differentiating bovine satellite cells, respectively. In addition, we identified 1,216 and 1,171 super-enhancers in proliferating and differentiating bovine satellite cells, respectively. Analyzing these enhancers showed that in proliferating bovine satellite cells, active enhancers were associated with genes stimulating cell proliferation or inhibiting myoblast differentiation whereas repressed enhancers were associated with genes essential for myoblast differentiation, and that in differentiating satellite cells, active enhancers were associated with genes essential for myoblast differentiation or muscle contraction whereas repressed enhancers were associated with genes stimulating cell proliferation or inhibiting myoblast differentiation. Active enhancers in proliferating bovine satellite cells were enriched with binding sites for many transcription factors such as MYF5 and the AP-1 family transcription factors; active enhancers in differentiating bovine satellite cells were enriched with binding sites for many transcription factors such as MYOG and TFAP4; and repressed enhancers in both proliferating and differentiating bovine satellite cells were enriched with binding sites for NF-kB, ZEB-1, and several other transcription factors. The role of TFAP4 in satellite cell or myoblast differentiation was previously unknown, and through gene knockdown and overexpression, we experimentally validated a critical role for TFAP4 in the differentiation and fusion of bovine satellite cells into myofibers.ConclusionsSatellite cell proliferation and differentiation are controlled by many transcription factors such as AP-1, TFAP4, NF-kB, and ZEB-1 whose roles in these processes were previously unknown in addition to those transcription factors such as MYF5 and MYOG whose roles in these processes are widely known.

Trichinella spiralis inhibits myoblast differentiation by targeting SQSTM1/p62 with a secreted E3 ubiquitin ligase

Trichinella spiralis infection is associated with the formation of cysts within host skeletal muscle cells, thereby enabling immune evasion and subsequent growth and development; however, the pathogenic factors involved in this process and their mechanisms remain elusive. Here, we found that Ts-RNF secreted by T.spiralis is required for its growth and development in host cells. Further study revealed that Ts-RNF functions as an E3 ubiquitin ligase that targets the UBA domain of SQSTM1/p62 by forming K63-type ubiquitin chains. This modification interferes with autophagic flux, leading to impaired mitochondrial clearance and abnormal myotube differentiation and fusion. Our results established that T.spiralis increases its escape by interfering with host autophagy via the secretion of an E3 ubiquitin ligase.

FGFs function in regulating myoblasts differentiation in spotted sea bass (Lateolabrax maculatus)

Fibroblast growth factors (FGFs) are a family of structurally related peptides that regulate processes such as cell proliferation, differentiation, and damage repair. In our previous study, fibroblast growth factor receptor 4 (fgfr4) was detected in the most significant quantitative trait loci (QTL), when identified of QTLs and genetic markers for growth-related traits in spotted sea bass. However, knowledge of the function of fgfr4 is lacking, even the legends to activate the receptor is unknown in fish. To remedy this problem, in the present study, a total of 33 fgfs were identified from the genomic and transcriptomic databases of spotted sea bass, of which 10 were expressed in the myoblasts. According to the expression pattern during myoblasts proliferation and differentiation, fgf6a, fgf6b and fgf18 were selected for further prokaryotic expression and purification. The recombinant proteins FGF6a, FGF6b and FGF18 were found to inhibit myoblast differentiation. Overall, our results provide a theoretical basis for the molecular mechanisms of growth regulation in economic fish such as spotted sea bass.

Nonsense-mediated mRNA decay suppresses injury-induced muscle regeneration via inhibiting MyoD transcriptional activity.

Skeletal muscle regeneration is a crucial physiological process that occurs in response to injury or disease. As an important transcriptome surveillance system that regulates tissue development, the role of nonsense-mediated mRNA decay (NMD) in muscle regeneration remains unclear. Here, we found that NMD inhibits myoblast differentiation by targeting the phosphoinositide-3-kinase regulatory subunit 5 gene, which leads to the suppression of the transcriptional activity of myogenic differentiation (MyoD), a key regulator of myoblast differentiation. This disruption of MyoD transcriptional activity subsequently affects the expression levels of myogenin and myosin heavy chain, crucial markers of myoblast differentiation. Additionally, through up-frameshift protein 1 knockdown experiments, we observed that inhibiting NMD can accelerate muscle regeneration in vivo. These findings highlight the potential of NMD as a novel therapeutic target for the treatment of muscle-related injuries and diseases.

Rab44 negatively regulates myoblast differentiation by controlling fusogenic protein transport and mTORC1 signaling.

Skeletal muscle is composed of multinucleated myotubes formed by the fusion of mononucleated myoblasts. Skeletal muscle differentiation, termed as myogenesis, have been investigated using the mouse skeletal myoblast cell line C2C12. It has been reported that several "small" Rab proteins, major membrane-trafficking regulators, possibly regulate membrane protein transport in C2C12 cells; however, the role of Rab proteins in myogenesis remains unexplored. Rab44, a member of "large" Rab GTPases, has recently been identified as a negative regulator of osteoclast differentiation. In this study, using C2C12 cells, we found that Rab44 expression was upregulated during myoblast differentiation into myotubes. Knockdown of Rab44 enhanced myoblast differentiation and myotube formation. Consistent with these results, Rab44 knockdown in myoblasts increased expression levels of several myogenic marker genes. Rab44 knockdown increased the surface accumulation of myomaker and myomixer, two fusogenic proteins required for multinucleation, implying enhanced cell fusion. Conversely, Rab44 overexpression inhibited myoblast differentiation and tube formation, accompanied by decreased expression of some myogenic markers. Furthermore, Rab44 was found to be predominantly localized in lysosomes, and Rab44 overexpression altered the number and size of lysosomes. Considering the underlying molecular mechanism, Rab44 overexpression impaired the signaling pathway of the mechanistic target of rapamycin complex1 (mTORC1) in C2C12 cells. Namely, phosphorylation levels of mTORC1 and downstream mTORC1 substrates, such as S6 and P70-S6K, were notably lower in Rab44 overexpressing cells than those in control cells. These results indicate that Rab44 negatively regulates myoblast differentiation into myotubes by controlling fusogenic protein transport and mTORC1 signaling.

E3 ligase Deltex2 accelerates myoblast proliferation and inhibits myoblast differentiation by targeting Pax7 and MyoD, respectively.

E3 ubiquitin ligases are closely related to cell division, differentiation, and survival in all eukaryotes and play crucial regulatory roles in multiple biological processes and diseases. While Deltex2, as a member of the DELTEX family ubiquitin ligases, is characterized by a RING domain followed by a C-terminal domain (DTC), its functions and underlying mechanisms in myogenesis have not been fully elucidated. Here, we report that Deltex2, which is highly expressed in muscles, positively regulates myoblast proliferation via mediating the expression of Pax7. Meanwhile, we find that Deltex2 is translocated from the nucleus into the cytoplasm during myogenic differentiation, and further disclose that Deltex2 inhibits myoblast differentiation and interacts with MyoD, resulting in the ubiquitination and degradation of MyoD. Altogether, our findings reveal the physiological function of Deltex2 in orchestrating myogenesis and delineate the novel role of Deltex2 as a negative regulator of MyoD protein stability.

Myostatin is a negative regulator of adult neurogenesis after spinal cord injury in zebrafish.

Intrinsic and extrinsic inhibition of neuronal regeneration obstruct spinal cord (SC) repair in mammals. In contrast, adult zebrafish achieve functional recovery after complete SC transection. While studies of innate SC regeneration have focused on axon regrowth as a primary repair mechanism, how local adult neurogenesis affects functional recovery is unknown. Here, we uncover dynamic expression of zebrafish myostatin b (mstnb) in a niche of dorsal SC progenitors after injury. mstnb mutants show impaired functional recovery, normal glial and axonal bridging across the lesion, and an increase in the profiles of newborn neurons. Molecularly, neuron differentiation genes are upregulated, while the neural stem cell maintenance gene fgf1b is downregulated in mstnb mutants. Finally, we show that human fibroblast growth factor 1 (FGF1) treatment rescues the molecular and cellular phenotypes of mstnb mutants. These studies uncover unanticipated neurogenic functions for mstnb and establish the importance of local adult neurogenesis for innate SC repair.

CircCSDE1 Regulates Proliferation and Differentiation of C2C12 Myoblasts by Sponging miR-21-3p.

The growth and development of skeletal muscle is regulated by many factors, and recent studies have shown that circular RNAs (circRNAs) can participate in this process. The model of porcine skeletal muscle injury was constructed to search for circRNAs that can regulate the growth and development of skeletal muscle in pigs. Using whole-transcriptome sequencing and bioinformatics analysis, a novel circRNA (circCSDE1) was screened out, which is highly expressed in skeletal muscle. Functional studies in C2C12 cells demonstrated that circCSDE1 could promote proliferation and inhibit myoblast differentiation, while opposing changes were observed by circCSDE1 knockdown. A dual-luciferase reporter assay revealed that circCSDE1 directly targeted miR-21-3p to regulate the expression of the downstream target gene (Cyclin-dependent kinase 16, CDK16). Moreover, miR-21-3p could inhibit proliferation and promote myoblast differentiation in C2C12 cells, opposite with the effects of circCSDE1. Additionally, the rescue experiments offered further evidence that circCSDE1 and its target, miR-21-3p, work together to regulate myoblast proliferation and differentiation. This study provides a theoretical basis for further understanding the regulatory mechanisms of circRNAs.

N-acetyl cysteine prevents arecoline-inhibited C2C12 myoblast differentiation through ERK1/2 phosphorylation.

Arecoline is known to induce reactive oxygen species (ROS). Our previous studies showed that arecoline inhibited myogenic differentiation and acetylcholine receptor cluster formation of C2C12 myoblasts. N-acetyl-cysteine (NAC) is a known ROS scavenger. We hypothesize that NAC scavenges the excess ROS caused by arecoline. In this article we examined the effect of NAC on the inhibited myoblast differentiation by arecoline and related mechanisms. We found that NAC less than 2 mM is non-cytotoxic to C2C12 by viability analysis. We further demonstrated that NAC attenuated the decreased number of myotubes and nuclei in each myotube compared to arecoline treatment by H & E staining. We also showed that NAC prevented the decreased expression level of the myogenic markers, myogenin and MYH caused by arecoline, using immunocytochemistry and western blotting. Finally, we found that NAC restored the decreased expression level of p-ERK1/2 by arecoline. In conclusion, our results indicate that NAC attenuates the damage of the arecoline-inhibited C2C12 myoblast differentiation by the activation/phosphorylation of ERK. This is the first report to demonstrate that NAC has beneficial effects on skeletal muscle myogenesis through ERK1/2 upon arecoline treatment. Since defects of skeletal muscle associates with several diseases, NAC can be a potent drug candidate in diseases related to defects in skeletal muscle myogenesis.

HDAC11 Regulates the Proliferation of Bovine Muscle Stem Cells through the Notch Signaling Pathway and Inhibits Muscle Regeneration.

Myogenesis is an essential process that can affect the yield and quality of beef. Transcriptional studies have shown that histone deacetylase 11 (HDAC11) was differentially expressed in muscle tissues of 6 and 18 month old Longlin cattle, but its role in the regulation of myogenesis remains unclear. This study aimed to determine the role of HDAC11 in the proliferation and differentiation of bovine muscle stem cells (MuSCs). HDAC11 promoted MuSC proliferation by activating Notch signaling and inhibited myoblast differentiation by reducing MyoD1 transcription. In addition, overexpression of HDAC11 inhibited the repair regeneration process of muscle in mice. HDAC11 was found to be a novel key target for the control of myogenesis, and this is a theoretical basis for the development of HDAC11-specific modulators as a new strategy to regulate myogenesis.

Kank1 Is Essential for Myogenic Differentiation by Regulating Actin Remodeling and Cell Proliferation in C2C12 Progenitor Cells.

Actin cytoskeleton dynamics are essential regulatory processes in muscle development, growth, and regeneration due to their modulation of mechanotransduction, cell proliferation, differentiation, and morphological changes. Although the KN motif and ankyrin repeat domain-containing protein 1 (Kank1) plays a significant role in cell adhesion dynamics, actin polymerization, and cell proliferation in various cells, the functional significance of Kank1 during the myogenic differentiation of progenitor cells has not been explored. Here, we report that Kank1 acts as a critical regulator of the proliferation and differentiation of muscle progenitor cells. Kank1 was found to be expressed at a relatively high level in C2C12 myoblasts, and its expression was modulated during the differentiation. Depletion of Kank1 by siRNA (siKank1) increased the accumulation of filamentous actin (F-actin). Furthermore, it facilitated the nuclear localization of Yes-associated protein 1 (YAP1) by diminishing YAP1 phosphorylation in the cytoplasm, which activated the transcriptions of YAP1 target genes and promoted proliferation and cell cycle progression in myoblasts. Notably, depletion of Kank1 suppressed the protein expression of myogenic regulatory factors (i.e., MyoD and MyoG) and dramatically inhibited myoblast differentiation and myotube formation. Our results show that Kank1 is an essential regulator of actin dynamics, YAP1 activation, and cell proliferation and that its depletion impairs the myogenic differentiation of progenitor cells by promoting myoblast proliferation triggered by the F-actin-induced nuclear translocation of YAP1.

MEF2C Expression Is Regulated by the Post-transcriptional Activation of the METTL3-m6A-YTHDF1 Axis in Myoblast Differentiation.

N6-methyladenosine (m6A) plays an essential role in regulating gene expression. However, the effect of m6A on skeletal myoblast differentiation and the underlying mechanisms are still unclear. Here, we ascertained mRNA m6A methylation exhibited declined changes during bovine skeletal myoblast differentiation, and both MEF2C mRNA expression and m6A levels were significantly increased during myoblast differentiation. We found that MEF2C with mutated m6A sites significantly inhibited myoblast differentiation compared with wild-type MEF2C. METTL3 promoted MEF2C protein expression through posttranscriptional modification in an m6A-YTHDF1-dependent manner. Moreover, MEF2C promoted the expression of METTL3 by binding to its promoter. These results revealed that there is a positive feedback loop between these molecules in myoblast differentiation. Our study provided new insights into skeletal muscle differentiation and fusion, which may provide an RNA methylation-based approach for molecular genetics and breeding in livestock as well as for the treatment of muscle-related diseases.

Benzo[a]pyrene inhibits myoblast differentiation through downregulating the Hsp70-MK2-p38MAPK complex

Cigarette smoking causes skeletal muscle dysfunction and worse prognosis for patients with diverse systemic diseases. Benzo[a]pyrene (BaP), one major constituent that is inhaled during smoking, is particularly known for its ability to impair neurodevelopment, impede reproductivity, or reduce birth weight. Here, we found that BaP exposure led to the inhibition of C2C12 myoblasts differentiation in a dose-dependent manner and reduced the expression of both early and late myogenic differentiation markers. BaP exposure significantly decreased the expression of p38 mitogen-activated protein kinase (p38MAPK), but not AKT, which are both critical during myogenic differentiation. Mechanistically, BaP downregulated the expression levels of MAPK-activated protein kinase 2 (MK2) and heat shock protein 70 (Hsp70), both of which stabilize p38MAPK. Interestingly, treatment of proteasome inhibitor MG132 was able to reverse BaP-induced degradation of Hsp70/ MK2 and p38MAPK in myoblasts, implying BaP-mediated p38MAPK degradation is proteasome-dependent. Overexpression of p38MAPK also rescued the defective differentiation phenotype of C2C12 induced by BaP. Taken together, we suggest that BaP exposure induces MK2/Hsp70/p38MAPK complex degradation in C2C12 myoblasts and impairs myogenic differentiation by proteasomal-dependent mechanisms. As application of the proteasome inhibitor MG132 or overexpression of p38MAPK could reverse impaired differentiation of myoblasts induced by BaP, this may suggest potential related strategies for preventing tobacco-related skeletal muscle diseases or for respiratory rehabilitation.

Knockdown of CDR1as Decreases Differentiation of Goat Skeletal Muscle Satellite Cells via Upregulating miR-27a-3p to Inhibit ANGPT1.

Myogenesis is a complex process controlled by several coding and non-coding RNAs (ncRNAs), such as circular RNAs (circRNAs) that are known to function as endogenous microRNAs (miRNAs) sponges. Cerebellar Degeneration-Related protein 1 antisense (CDR1as) is the most spotlighted circRNA that is known as an miR-7 sponge, which has bloomed circRNAs’ research in animal disease and physiology. Here, we screened for miRNAs and mRNA associated with CDR1as and further characterized their regulatory function during muscle differentiation. We found that a total of 43 miRNAs (including miR-107-3p, miR-125b-5p, miR-140-5p, miR-29a-3p, and miR-27a-3p upregulated) and 789 mRNAs (including ANGPT1, E2F2, CCN1, FGFR1, and MEF2C downregulated) were differentially expressed in goat skeletal muscle satellite cells (SMSCs). Further, knockdown of CDR1as and ANGPT1 inhibited SMSCs differentiation. miR-27a-3p was differentially upregulated after the knockdown of CDR1as in SMSCs. Overexpressed miR-27a-3p decreased SMSCs differentiation. Via RNAhybrid and luciferase, miR-27a-3p was identified to regulate ANGPT1. We discovered that miR-27a-3p has an inverse relationship with CDR1as and decreases the expression level of ANGPT1 during SMSCs differentiation. In summary, our study demonstrates that siCDR1as inhibits myoblast differentiation by downregulating ANGPT1 mRNA via miR-27a-3p in SMSCs.

Identification and Functional Characterization of Metabolites for Skeletal Muscle Mass in Early Postmenopausal Chinese Women.

Low skeletal muscle mass (SMM) is a crucial component of the sarcopenia phenotypes. In the present study, we aim to identify the specific metabolites associated with SMM variation and their functional mechanisms of decreased SMM in early postmenopausal women. We performed an untargeted metabolomics analysis in 430 early postmenopausal women to identify specific metabolite associated with skeletal muscle mass indexes (SMIes). Then, the potential causal effect of specific metabolite on SMM variation was accessed by one-sample Mendelian randomization (MR) analysis. Finally, in vitro experiments and transcriptomics bioinformatics analysis were conducted to explore the impact and potential functional mechanisms of specific metabolite on SMM variation. We detected 65 metabolites significantly associated with at least one SMI (variable importance in projection > 1.5 by partial least squares regression and p < .05 in multiple linear regression analysis). Remarkably, stearic acid (SA) was negatively associated with all SMIes, and subsequent MR analyses showed that increased serum SA level had a causal effect on decreased SMM (p < .05). Further in vitro experiments showed that SA could repress myoblast's differentiation at mRNA, protein, and phenotype levels. By combining transcriptome bioinformatics analysis, our study supports that SA may inhibit myoblast differentiation and myotube development by regulating the migration, adhesion, and fusion of myoblasts. This metabolomics study revealed specific metabolic profiles associated with decreased SMM in postmenopausal women, first highlighted the importance of SA in regulating SMM variation, and illustrated its potential mechanism on decreased SMM.

Trillin inhibits myoblast differentiation via increasing autophagy

BackgroundTrillin, an active ingredient in traditional Chinese medicine Trillium tschonoskii, is a potential small molecule compound candidate that affecting myoblast differentiation, which predicting by AI technology in our previous study. Autophagy modulating myoblast differentiation has also been studied. In addition, Trillin was shown to regulate mTOR signaling pathway, a highly conserved kinase important for autophagy regulation. PurposeIn this research, we aim to clarify the effect and underlying mechanism of Trillin on myoblast differentiation. Study design and methodsUsing mice C2C12 cell line to establish a myoblast differentiation model in vitro, treated with different concentration and time of Trillin, to explore the effect and latent mechanism of Trillin on myoblast differentiation by qRT-PCR, Western Blot and other molecular biological technique. ResultsResults showed that C2C12 differentiation was significantly inhibited by Trillin in a dose-dependent manner. The expression of MyHC, MyOG and MyoD was decreased extremely significant after 10 μM Trillin treatment. Meanwhile, autophagy level was significantly elevated with the supplement of Trillin. And C2C12 differentiation was recovered after ATG7 knockdown. Mechanically, we found that the activity of AKT/mTOR declined during the inhibition of differentiation by Trillin. ConclusionOur findings suggested that Trillin attenuated C2C12 differentiation via increasing autophagy through AKT/mTOR signaling pathway. Taken together, we introduce a novel physiological function of Trillin in inhibiting skeletal muscle differentiation.