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At least 19 recordsLinked to original sources
PubMed1975

Differences among myosins synthesized in non-myogenic cells, presumptive myoblasts, and myoblasts.

Myosins synthesized in non-myogenic cells and replicating presumptive myoblasts differ from those synthesized in postmitotic mononucleated myoblasts and myotubes. Myoblasts and myotubes synthesize the definitive light chains, MLC1 and MLC2. These light chains display different molecular weights in sodium dodecyl sulfate-polyacrylamide gels from the fibroblast light chains FLC1 and FLC2 synthesized in non-myogenic cells and presumptive myoblasts. There are immunological differences between the myosin heavy chains synthesized in myoblasts and myotubes and those synthesized in non-myogenic cells and presumptive myoblasts. Fluorescein-labeled antibodies against skeletal light meromyosin are bound only along the lateral edges of emerging and definitive A-bands. This antibody to light meromyosin is not bound to the outside of, or the microfilaments subtending, the plasma membrane in non-myogenic cells or in myoblasts or in myotubes. These findings suggest that: (1) non-myogenic cells and replicating presumptive myoblasts synthesize similar myosin heavy and light chains; (2) replicating presumptive myoblasts synthesize a different set of myosins from those synthesized by their postmitotic daughters, the myoblasts; (3) the myosins associated with the plasma membranes of non-myogenic and myogenic cells are products of structural genes distinct from those coding for the myosins for skeletal myofibrils.

Animals↗
PubMed1992

Circulating human or canine factor IX from retrovirally transduced primary myoblasts and established myoblast cell lines grafted into murine skeletal muscle.

We have used retroviral vectors to introduce human or canine factor IX cDNAs into cultured primary murine and canine myoblasts and into the established murine myoblast cell line C2C12. In all cases, the stably infected cells produced biologically active factor IX in culture and secreted detectable amounts into the culture medium both before and after differentiation of the cells into myotubes. Myoblasts and differentiated myotubes are therefore capable of performing all the posttranslational modifications of the coagulation factor required for biological activity. We have grafted the genetically modified myoblasts into skeletal muscles of nude mice and have detected stable levels of circulating human factor IX for up to two months after grafting. We propose that grafting genetically modified primary myoblasts or established myoblast cell lines into skeletal muscle may represent a useful approach to gene therapy for a variety of genetic diseases, including intrinsic muscle disease and defects in circulating proteins as in the hemophilias.

Animals↗
PubMed1992

Differentiation of quail myoblasts transformed with a temperature sensitive mutant of Rous sarcoma virus. II. Relationship of myoblast fusion with calcium and temperature.

The effects of calcium and temperature on fusion of quail embryonic myoblasts were examined using cells transformed with a temperature-sensitive mutant of Rous sarcoma virus (ts-RSV). The transformed quail myoblasts (QM-RSV) fused to form myotubes at 41 degrees C, the non-permissive temperature, but not at 35.5 degrees C, the permissive temperature. On incubation at 41 degrees C, a period of more than 10 hr was needed for the myoblasts to become fusion-competent, but calcium was not needed for development of fusion-competence. Once the cells had become competent, fusion proceeded even at 35.5 degrees C. These results suggest that the src gene product expressed at 35.5 degrees C may control the fusion of cells in the competent stage by inactivating a component(s) that is associated with fusion-competence. However, fusion of even myoblasts in the competent stage was blocked in calcium-deficient medium, suggesting that calcium is essential for the fusion, probably at a step immediately before membrane union. Unlike fusion, other biochemical processes of differentiation proceeded even in calcium-deficient medium, indicating a distinction of fusion from these other processes during myoblast differentiation.

Animals↗
PubMed1990

Affinity labeling of myoblast surface proteins with 5'-P-fluorosulfonylbenzoyl adenosine: concomitant inhibition of ectoprotein kinase activity and myoblast fusion.

During in vitro myogenesis, mononucleated myoblasts fuse among themselves to form multinucleated myotubes. We have recently reported for the first time in the literature that a Ca2(+)-dependent ectoprotein kinase is responsible for this process, but we had no direct evidence for the role of extracellular ATP. To investigate whether the cells can fuse or not in the absence of this nucleotide, we used a nucleotide affinity label, fluorosulfonylbenzoyl adenosine (FSBA). We report here its use in detecting the nucleotide-binding sites at the cell surface of intact myoblasts in culture. We demonstrate that FSBA blocks fusion by inhibiting the ectoprotein kinase activity of the cells at sublethal concentrations. Radioactive [14C]SBA is incorporated into seven cell surface proteins and into the 48-kDa protein, among others. This species is specific for fusion-competent myoblasts and is implicated in this process. This is the first time that nucleotide-binding molecular species have been identified at the surface of myoblasts.

Adenosine↗
PubMed1978

A comparative study of the myosin light chain kinases from myoblast and muscle sources. Studies on the kinases from proliferative rat myoblasts in culture, rat thigh muscle, and rabbit skeletal muscle.

Myosin light chain kinases have been isolated from rat thigh and rabbit skeletal muscle and cultured rat myoblasts. From these preparations, two types of kinases can be distinguished: calcium-dependent and calcium-independent. Both types of kinases can phosphorylate isolated P-light chains of myosin from several sources (skeletal muscle, cardiac muscle, and platelet). Data are shown which support the phosphorylation of the same site on the non-muscle P-light chains by both types of kinases. The rates of these reactins are, however, different for the two types of kinases. Kinetic analysis of the myoblast kinase shows differing affinities for various P-light chains (non-muscle greater than cardiac greater than skeletal). In the proliferative rat myoblast, phosphorylation of myosin is a prerequisite for actin activation of the myosin ATPase activity.

Adenosine Triphosphatases↗
PubMed1990

Accelerated age-related decline in replicative life-span of Duchenne muscular dystrophy myoblasts: implications for cell and gene therapy.

An assessment of the replicative life-span of myoblasts is of fundamental importance in designing treatment strategies for Duchenne muscular dystrophy (DMD) based on cell or gene therapy. To ascertain myoblast life-span, or the total number of cell divisions of which a myoblast was capable, we serially passaged and counted the progeny of individual myoblasts until they senesced. We compared the life-span of myoblasts from eight DMD patients with controls: three individuals with no known neuromuscular disease, three DMD carriers, and three patients with other muscle degenerative diseases. A decline in replicative capacity was observed with increasing donor age, which was markedly accelerated for DMD relative to control myoblasts. The average myoblast from a 5-year-old control was capable of 56 doublings, or a potential yield of approximately 10(17) cells per cell. By contrast, at 2 years of age, the typical age at clinical onset, only 6% of DMD myoblasts had a life-span of 50 doublings in tissue culture, and by age 7 DMD myoblasts capable of 10 doublings were rare. Our results suggest that the myoblasts (satellite cells) of even the youngest DMD patients have undergone extensive division in an attempt to regenerate degenerating myofibers. These findings have implications for therapeutic intervention in DMD involving genetic engineering and myoblast implantation.

Age Factors↗
PubMed1979

Immunological studies of the embryonic muscle cell surface. Antiserum to the prefusion myoblast.

Xenogeneic antisera raised in rabbits have been used to detect compositional changes at the cell surfaces of differentiating embryonic chick skeletal muscle. In this report, we present the serological characterization of antiserum (Anti-M-24) against muscle tissue and developmental stage-specific cell surface antigens of the prefusion myoblast. Cells from primary cultures of 12-d-old embryonic chick hindlimb muscle were injected into rabbits, and the resulting antisera were selectively absorbed to obtain immunological specificity. Cytotoxicity and immunohistochemical assays were used to test this antiserum. Absorption with embryonic or adult chick heart, brain, retina, liver, erythrocytes, or skeletal muscle fibroblasts failed to remove all reactivity of Anti-M-24 for myogenic cells at all stages of development. After absorption with embryonic myotubes, however, Anti-M-24 no longer reacted with differentiated myofibers, but did react with prefusion myoblasts. The myoblast surface antigens detected with Anti-M-24 are components of the muscle cell membrane: (a) these macromolecules are free to diffuse laterally within the myoblast membrane; (b) Anti-M-24, in the presence of complement, induced lysis of the muscle cell membrane; and (c) intact monolayers of viable myoblasts completely absorbed reactivity of Anti-M-24 for myoblasts. These antigens are not loosely adsorbed culture medium components or an artifact of tissue culture because: (a) absorption of Anti-M-24 with homogenized embryonic muscle removed all antibodies to cultured myoblasts; (b) Anti-M-24 reacted with myoblast surfaces in vivo; and (c) absorption of Anti-M-24 with culture media did not affect the titer of this antiserum for myoblasts. We conclude that myogenic cells at all stages of development possess externally exposed antigens which are undetected on other embryonic and adult chick tissues. In addition, myoblasts exhibit surface antigenic determinants that are either masked, absent, or present in very low concentrations on skeletal muscle fibroblasts, embryonic myotubes, or adult myofibers. These antigens are free to diffuse laterally within the myoblast membrane and may be modulated in response to appropriate environmental cues during myodifferentiation.

Animals↗
PubMed1992

Feasibility, safety, and efficacy of myoblast transfer therapy on Duchenne muscular dystrophy boys.

Five billion normal myoblasts were injected into each of 21 Duchenne muscular dystrophy (DMD) boys aged 6-14 yr to assess the feasibility, safety, and efficacy of the Phase II myoblast transfer therapy (MTT). The Phase II study was designed to strengthen muscles of both lower limbs. Forty-eight intramuscular injections transferred the myoblasts into 22 major muscles at 55.6 x 10(6)/mL in 10 min under general anesthesia. Eleven boys had received 8 million myoblasts each 1 yr ago in the Phase I MTT. In the Phase II study, eight of them had their myoblasts subcultured from reserves frozen 1 yr ago. The donor myoblasts for each of the remaining boys were cultured from satellite cells derived from a 1-g muscle biopsy of a normal male who might or might not be histocompatible with the recipient. The immunosuppressant cyclosporine (Cy) is being administered to recipients for 6 mo after MTT to facilitate donor cell survival. There was no evidence of an adverse reaction to MTT or Cy as determined by serial laboratory evaluations including electrolytes, creatinine, and urea. Early objective functional tests using the KinCom Robotic Dynamometer were conducted on 13 subjects aged 6 to 13 before MTT and at 3 mo after MTT. Of the 69 muscle groups (knee extensors, knee flexors, plantar flexors) tested for isometric force generation in these subjects, 43% showed mean increase of 41.3% +/- 5.9 SEM, 38% showed no change, and 19% showed continuous force reduction of 23.4% +/- 3.1 SEM. The remaining subjects await the 3-mo post-MTT evaluation. The results indicate that 1) MTT is safe; 2) MTT increases muscle strength in DMD: 81% of the muscles tested showed either increase in strength or did not show continuous loss of strength; 3) more than 5 billion myoblasts can be cultured from 1 g normal muscle biopsy, providing unprecedented numbers of cells for MTT; 4) myoblasts, frozen over 1 yr, retain the ability to proliferate from 10 million to 5 billion, and to form normal myofibers; 5) injections of 5 billion myoblasts have not provoked any immunological rejection symptoms in the Phase II subjects, 11 of whom received 8 million myoblasts in the Phase I MTT a year ago; 6) it is safe to perform multiple injections of myoblasts into lower limb muscles without formation of emboli; and 7) donor cell rejection by the recipient can be prevented with Cy when properly managed.

Adolescent↗
PubMed1988

The control of chick myoblast fusion by ion channels operated by prostaglandins and acetylcholine.

Chick myoblast fusion in culture was investigated using prostanoid synthesis inhibitors to delay spontaneous fusion. During this delay myoblast fusion could be induced by prostaglandin E1 (PGE1), by raising extracellular potassium and by addition of carbachol. Carbachol-induced fusion, but not PGE-induced fusion, was prevented by the acetylcholine receptor blocker alpha-bungarotoxin. Fusion induced by any of these agents was prevented by the Ca channel blockers lanthanum and D600. The threshold for potassium-induced fusion was 7-8 mM; maximal fusion occurred at 16-20 mM. Low extracellular potassium inhibited spontaneous fusion. Intracellular potassium in fusion competent myoblasts was 101 m-moles/l cell. Calcium flux measurements demonstrated that high potassium increased calcium permeability in fusion-competent myoblasts. A 30-s exposure to high potassium or PGE1 was sufficient to initiate myoblast fusion. Anion-exchange inhibitors (SITS and DIDS) delayed spontaneous myoblast fusion and blocked fusion induced by PGE1 but not carbachol. Blocking the acetylcholine receptor shifted the dose-response relation for PGE-induced fusion to higher concentrations. PGE1-induced fusion required chloride ions; carbachol-induced fusion required sodium ions. Provided calcium channels were available, potassium always induced fusion. We conclude that myoblasts possess at least three, independent pathways, each of which can initiate myoblast fusion and that the PGE-activated pathway and the acetylcholine receptor-activated pathway act synergistically. We suggest that fusion competent myoblasts have a high resting membrane potential and that fusion is controlled by depolarization initiated directly (potassium), by an increase in permeability to chloride ions (PGE), or by activation of the acetylcholine receptor (carbachol); depolarization triggers a rise in calcium permeability. The consequent increase in intracellular calcium initiates myoblast fusion.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

Preferential binding of insulin-like growth factor-II (IGF-II) to a putative alpha 2 beta 2 IGF-II receptor type in C2 myoblasts.

We have studied insulin-like-growth-factor (IGF) binding in two subclones of the C2 myogenic cell line. In the permissive parental subclone, myoblasts differentiate spontaneously into myotubes in medium supplemented with fetal calf serum. Unlike permissive myoblasts, inducible myoblasts require high concentrations of insulin (1.6 microM) or lower concentrations of IGF-I (25 nM) to differentiate, and expression of MyoD1 is not constitutive. IGF receptors were studied in microsomal membranes of proliferating and quiescent myoblasts and myotubes. IGF-II binding was also studied in inducible myoblasts transfected with the MyoD1 cDNA (clone EP5). Both inducible and permissive cells exhibited a single class of binding sites with similar affinity for IGF-I (Kd 0.8-1.2 nM). Affinity cross-linking of [125I]IGF-I to microsomal membranes, under reducing conditions, revealed a binding moiety with an apparent molecular mass of 130 kDa in permissive cells and 140 kDa in inducible cells, which corresponded to the alpha subunit of the IGF-I receptor. In permissive quiescent myoblasts, linear Scatchard plots suggested that [125I]IGF-II bound to a single class of binding sites (Kd 0.6 nM) compatible with binding to the IGF-II/M6P receptor. This was confirmed by affinity cross-linking experiments showing a labeled complex with an apparent molecular mass of 260 kDa and 220 kDa when studied under reducing and non-reducing conditions, respectively. In contrast, competitive inhibition of [125I]IGF-II binding to inducible quiescent myoblasts generated curvilinear Scatchard plots which could be resolved into two single classes of binding sites. One of them corresponded to the IGF-II/M6P receptor (Kd 0.2 nM) as evidenced by cross-linking experiments. The second was the binding site of highest affinity (Kd 0.04 nM) which was less inhibited by IGF-I than by IGF-II and was not inhibited by insulin. It migrated in SDS/PAGE at a position equivalent a molecular mass of 140 kDa, under reducing conditions, and at approximately 300 kDa, under non-reducing conditions. The labeling of this atypical binding moiety was not inhibited by anti(IGF-II/M6P-receptor) immunoglobulin. It was also observed in permissive and inducible myoblasts at proliferating stage. It was absent for permissive quiescent myoblasts and from permissive and inducible myotubes. Forced expression of MyoD1 in inducible cells (EP5 cells) dramatically reduced [125I]IGF-II binding to this atypical receptor. It emerges from these experiments that C2 cells express a putative alpha 2 beta 2 IGF-II receptor structurally related to the insulin/IGF-I receptor family. It is present in myoblasts but not in myotubes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Human myoblasts as antigen-presenting cells.

Human myoblasts, cultured from muscle and purified to greater than 95%, were investigated for their capacity to act as facultative APC. The myoblasts reacted with antidesmin mAb and had the capacity to fuse into multinucleated myotubes in appropriate medium. The expression of HLA class I, HLA-DR, HLA-DP, HLA-DQ, intercellular adhesion molecule-1 (ICAM-1/CD54), lymphocyte function-associated (LFA) molecules LFA-1 (CD11a/CD18), LFA-2 (CD2), and LFA-3 (CD58) was investigated by FACS analysis before and after induction for various times with human rIFN-gamma, TNF-alpha, or both. Without cytokine induction, myoblasts expressed only HLA-class I and LFA-3. IFN-gamma alone or in combination with TNF-alpha induced the expression of HLA-DR and ICAM-1 reaching a plateau after 48 h, followed by HLA-DP and even later HLA-DQ. TNF-alpha alone induced only ICAM-1. The functional capacity of myoblasts to present Ag to CD4+ T cells was investigated using autologous T cell lines specific for tuberculin, tetanus toxoid, and human myelin basic protein. Noninduced myoblasts or myoblasts treated with TNF-alpha alone could not present any of these Ag to the T cells. However, myoblasts treated with IFN-gamma induced Ag-specific proliferation. In the presence of relevant Ag, myoblasts were killed by the T cells as observed by microscopy and measured by 51Cr release. Ag-specific T cell proliferation and myoblast killing was inhibited in the presence of anti-DR mAb. These results suggest that human myoblasts may act as facultative APC during local immune reactions in muscle.

Antigen-Presenting Cells↗
PubMed1990

c-fos reduces growth factor requirements for mitogenic stimulation of L6 rat myoblasts.

Addition of fetal calf serum (FCS) to serum-deprived L6J1 rat myoblasts increases fos-like immunoreactivity. The nuclear immunoreactivity reached a maximum 2 h after serum addition. Effects of the c-fos protein on myoblast proliferation were analyzed in L6J1 rat myoblasts transfected with the murine c-fos gene under control of a metallothionein promoter. L6J1 myoblasts with elevated expression of transfected c-fos reached higher cell densities than neo transfected control myoblasts when approaching a stationary phase in normal culture conditions (5% FCS). The differences in cell densities were even more pronounced at low serum concentrations (0.5% FCS). c-fos transfected cells also had a faster growth rate than did control cells in serum-free medium supplemented with calcium chloride, lithium chloride, sodium selenite, hydrocortisone, and insulin. The cell morphology of c-fos transfected L6J1 myoblasts was not affected compared to control myoblasts. These results suggest that c-fos protein expression in L6J1 myoblasts is activated by serum and that mitogenic stimulation of L6J1 myoblasts is facilitated by the presence of elevated amounts of c-fos protein.

Animals↗
PubMed1990

A role for the Ca2(+)-dependent adhesion molecule, N-cadherin, in myoblast interaction during myogenesis.

The formation of multinucleate skeletal muscle cells (myotubes) is a Ca2(+)-dependent process involving the interaction and fusion of mononucleate muscle cells (myoblasts). Specific cell-cell adhesion precedes lipid bilayer union during myoblast fusion and has been shown to involve both Ca2(+)-independent (CI)2 and Ca2(+)-dependent (CD) mechanisms. In this paper we present evidence that CD myoblast adhesion involves a molecule similar or identical to two known CD adhesion glycoproteins, N-cadherin and A-CAM. These molecules were previously identified by other laboratories in brain and cardiac muscle, respectively, and are postulated to be the same molecule. Antibodies to N-cadherin and A-CAM immunoblotted a similar band with a molecular weight of approximately 125,000 in extracts of brain, heart, and pectoral muscle isolated from chick embryos and in extracts of muscle cells grown in vitro at Ca2+ concentrations that either promoted or inhibited myotube formation. In assays designed to measure the interaction of fusion-competent myoblasts in suspension, both polyclonal and monoclonal anti-N-cadherin antibodies inhibited CD myoblast aggregation, suggesting that N-cadherin mediates the CD aspect of myoblast adhesion. Anti-N-cadherin also had a partial inhibitory effect on myotube formation likely due to the effect on myoblast-myoblast adhesion. The results indicate that N-cadherin/A-CAM plays a role in myoblast recognition and adhesion during skeletal myogenesis.

Animals↗
PubMed1991

Infection and inhibition of differentiation of human fetal skeletal myoblasts by adenovirus.

The effects of adenovirus type 5 infection on the differentiation of cultured human skeletal myoblasts and of myoblast differentiation on the replication of adenovirus were investigated. Although infection of myoblasts concurrently with differentiation induction was inhibitory, myoblast differentiation was not impeded when infection was carried out 2 hr or later after induction. Similar studies conducted with E1A mutant viruses (dI312, pm975, and dI1500) revealed that complete inhibition was dependent on the product of 13 S E1A transcript expression, although partial inhibition could be induced by the 12 S product. Differentiation of myoblasts results in the generation of multinucleated myotubes and quiescent mononuclear cells. The three cell types (myoblasts, myotubes, mononuclear cells) were differentially permissive to adenovirus infection. The precursor myoblasts and the multinucleated myotubes were found to be permissive for adenovirus infection. The kinetics of their infection was delayed 24-48 hr relative to that of HeLa cells. Quiescent mononuclear cells in the differentiated myoblast cultures were found to be inefficient in supporting the production of adenovirus particles, despite the accumulation of adenovirus DNA and capsid proteins. Host protein synthesis in the three cell types also responded differently to adenovirus infection. In the multinucleated myotubes, host protein synthesis was potently inhibited by adenovirus at late times after infection, whereas it persisted in the proliferating myoblasts and quiescent mononuclear cells.

Adenoviridae Infections↗
PubMed1991

Recombinant platelet-derived growth factor-BB stimulates growth and inhibits differentiation of rat L6 myoblasts.

We previously found that L6 myoblasts and skeletal muscle isolated from developing rats express the platelet-derived growth factor (PDGF) beta-receptor gene (Jin, P., Rahm, M., Claesson-Welsh, L., Heldin, C.-H., and Sejersen, T. (1990) J. Cell Biol. 110, 1665-1672). We now report that recombinant human PDGF-BB is a mitogen for L6 myoblasts and also a potent inhibitor of myogenic differentiation. Treatment of L6J1 myoblasts with PDGF-BB increased the rate of DNA synthesis and stimulated cell proliferation. In differentiation medium (Dulbecco's modified Eagle's medium/0.5% fetal calf serum or Dulbecco's modified Eagle's medium/insulin), PDGF-BB prevented fusion of confluent myoblasts and suppressed biochemical differentiation in L6J1 cells. Inhibition of myoblast differentiation was, however, reversible. Withdrawal of PDGF-BB from the medium allowed myoblast fusion to occur. Northern blot hybridization showed that the PDGF beta-receptor mRNA was down-regulated to an undetectable level when confluent cultures of L6J1 myoblasts in growth medium (Dulbecco's modified Eagle's medium/5% fetal calf serum) were shifted to differentiation medium. Receptor binding assays further indicated that binding of PDGF-BB to its receptors on L6J1 myoblasts declined rapidly before creatine kinase activity rose. Our results provide the first demonstration that PDGF-BB is a potent regulator of myogenesis of L6 rat myoblasts and suggest that it may regulate muscle differentiation in vivo.

Animals↗
PubMed2026

Screening and identification of the ncRNA-mRNA regulatory network associated with DNA methylation in goose embryonic myoblasts.

BACKGROUND: Local goose breeds Shitou and Wuzong exhibit distinct growth rates, implying divergent embryonic muscle development. This study used embryonic myoblasts from the Magang goose, an established model with superior growth traits, to explore the underlying common regulatory mechanisms. Extending our previous findings that 5-AZA (DNA methylation inhibitor) and BC339 (DNA hydroxylation inhibitor) oppositely affect myoblast proliferation and differentiation, we performed whole-transcriptome sequencing on inhibitor-treated goose embryonic myoblasts. This aimed to identify DNA methylation-mediated ncRNA-mRNA networks governing myoblast fate, with key interactions being functionally validated. RESULT: 5-AZA significantly promotes cell proliferation and differentiation by inhibiting DNA methyltransferase activity and reducing DNA methylation levels, whereas BC339 significantly suppresses cell proliferation and differentiation by inhibiting demethylation and increasing DNA methylation levels. Specifically, we identified 6,309 mRNAs, 579 lncRNAs, 194 miRNAs, and 825 circRNAs that were differentially expressed in response to 5-AZA and BC339 treatment. Based on GO and KEGG enrichment analyses, differentially expressed genes related to muscle development were selected to construct a ceRNA network. This network comprises 5 differentially expressed lncRNAs (DELs: MSTRG.17572.1, XR_001211738.1, MSTRG.1886.1, XR_001212555.1, MSTRG.8995.2), 2 differentially expressed circRNAs (DECs: novel_circ_029953, novel_circ_017636), 11 differentially expressed miRNAs (DEMs: miR-383-x, miR-10174-y, miR-191-x, miR-24-x, miR-9619-y, novel-m0303-5p, novel-m0105-3p, miR-204-x, miR-211-z, novel-m0075, miR-26-y), 5 differentially expressed genes (DEGs: KIF3A, CCND1, PPM1A, Table 2, TGFBR1), forming a total of 24 interactions. This study identified miR-9619-y as a critical negative regulator of goose embryonic myoblast development through targeted inhibition of CCND1. Dual-luciferase reporter assays confirmed the direct binding of miR-9619-y to the 3'-untranslated region of CCND1. Functional experiments demonstrated that overexpression of miR-9619-y significantly reduced the EdU-positive cell ratio and myotube area percentage, accompanied by cell cycle arrest at the G0/G1 phase. Conversely, inhibition of miR-9619-y promoted myoblast proliferation and differentiation while decreasing the proportion of cells in G0/G1 phase. During the proliferation stage, miR-9619-y overexpression significantly suppressed CCND1 expression at both mRNA and protein levels, down-regulated MyoD expression, and reduced Myf5 mRNA abundance; whereas miR-9619-y inhibition up-regulated these genes and their corresponding proteins. During the differentiation stage, overexpression of miR-9619-y similarly decreased the mRNA levels of CCND1, Myh1, and MyoG, as well as the protein levels of MyHC and CCND1, with inhibition producing the opposite effects. CONCLUSION: In this study, we predicted a ceRNA network based on bioinformatics analysis governing goose embryonic myoblast development, identifying key molecular components including mRNAs, miRNAs, lncRNAs, and circRNAs, along with 24 regulatory axes. Functional experiments further demonstrated that miR-9619-y arrests cell cycle progression and negatively regulates the proliferation and differentiation of goose embryonic myoblasts, as evidenced by its impact on both the mRNA and protein expression of key myogenic factors through targeted inhibition of CCND1. These findings, together with the bioinformatically predicted ceRNA network, suggest potential complex post-transcriptional regulatory mechanisms underlying myogenesis in geese and offer candidate molecular targets for genetic improvement of meat production performance in waterfowl breeding programs.

Animals↗