Development of a novel Japanese eel myoblast cell line for application in cultured meat production.

The present study investigates the isolation, analysis, and characterization of primary cultured cells derived from the muscle tissue of Japanese eel (Anguilla japonica), culminating in establishing a spontaneously immortalized myoblast cell line, JEM1129. We isolated satellite cells from eel muscle tissue to establish a foundation for cultured eel meat production. While initial cell cultures contained myoblasts, continued passaging led to a decline in myoblast characteristics and an increase in fibroblast-like cells. RNA-Seq and RT-qPCR analyses showed significant downregulation of well-established markers for satellite cells and myoblasts, such as pax7a and myoD, over successive passages, highlighting a loss of myoblastic traits. Single-cell cloning was employed to overcome this challenge and maintain myoblast purity, leading to the successful creation of the JEM1129 cell line. These JEM1129 cells demonstrated enhanced expression of myoblast marker genes, exceeding the initial primary culture cell population. The cells showed strong myotube formation, particularly when cultured in a differentiation medium, indicating their robust potential for muscle development. The JEM1129 cell line represents a significant advancement in the cultivation of eel muscle cells, offering a promising avenue for cultured meat production. The findings contribute to a deeper understanding of muscle cell biology and provide valuable insights into using fish-derived myoblasts for cultured meat production.

Establishment and Characterization of a Chicken Myoblast Cell Line.

Skeletal muscle, which is predominantly constituted by multinucleated muscle fibers, plays a pivotal role in sustaining bodily movements and energy metabolism. Myoblasts, which serve as precursor cells for differentiation and fusion into muscle fibers, are of critical importance in the exploration of the functional genes associated with embryonic muscle development. However, the in vitro proliferation of primary myoblasts is inherently constrained. In this study, we achieved a significant breakthrough by successfully establishing a chicken myoblast cell line through the introduction of the exogenous chicken telomerase reverse transcriptase (chTERT) gene, followed by rigorous G418-mediated pressure screening. This newly developed cell line, which was designated as chTERT-myoblasts, closely resembled primary myoblasts in terms of morphology and exhibited remarkable stability in culture for at least 20 generations of population doublings without undergoing malignant transformation. In addition, we conducted an exhaustive analysis that encompassed cellular proliferation, differentiation, and transfection characteristics. Our findings revealed that the chTERT-myoblasts had the ability to proliferate, differentiate, and transfect after multiple rounds of population doublings. This achievement not only furnished a valuable source of homogeneous avian cell material for investigating embryonic muscle development, but also provided valuable insights and methodologies for establishing primary cell lines.

Proteomic Analysis of Glucose-Induced Cardiac Myoblasts and the Potential Role of mir-92b-5p in Regulating Sarcomere Proteins Under a Hyperglycemic Environment.

BACKGROUND: Diabetes mellitus, a common metabolic disorder that causes high blood glucose, is due to impaired insulin secretion. Prolonged high blood sugar is associated with heart disease. Many proteins are involved in metabolic pathways and contractility of cardiac cells regulate cardiac hypertrophy, altering normal cardiac physiology and function. Moreover, microRNAs are essential regulators of these proteins. Thus, there is a need to study the protein and microRNA alterations in cardiomyocytes to better understand the mechanisms activated during cardiac stress. OBJECTIVE: The study aims to profile differentially expressed sarcomere proteins in H9C2 cell lines under high glucose conditions compared with normal conditions, along with the identification of miRNAs regulating these proteins. METHODS: Cardiac myoblast cell lines were treated with D-Glucose at three concentrations (10 mM, 25 mM, and 50 mM). Total cell protein was analyzed by Tandem Mass spectrometry Nano LCMS/ MS. Furthermore, next-generation sequencing data were analyzed for detecting microRNAs regulating cardiac cell protein expression. Bioinformatics databases such as Uniprot, Ingenuity Pathway Analysis (IPA), PANTHER, and Target scan were used. RESULTS: The Nano LC-MS/MS analysis showed 2891 protein, 1351 protein groups, and 4381 peptide groups in both glucose-treated and control samples. Most proteins were metabolite interconversion enzymes, translation proteins, and proteins regulating the cytoskeleton. IPA analysis revealed differentially expressed proteins involved in EIF2 signaling, actin cytoskeleton signaling, cardiac fibrosis, and cell death. Moreover, the proteins troponin, tropomyosin, myosin, alpha-actin, and ATP synthase were found to be downregulated, thus responsible for altering sarcomere protein expression. Rno-mir-92b-5p was observed to be highly upregulated at 50 mM. Its target genes namely TPM2, ATP1A2, and CORO1C were mostly components of the sarcomere complex and its regulators. CONCLUSION: A combination of proteomic profile and microRNA profile of hyperglycemic cells provides an insight into advanced therapeutics. Our study has highlighted the role of sarcomere proteins, activation of Eukaryotic Initiation Factor 2 (EIF2) signaling, and suppression of actin cytoskeleton signaling in the pathophysiology of cardiomyopathy. MiR-92b-5p has an important role in regulating sarcomere protein complex activated.

Regulatory Action of Plasma from Patients with Obesity and Diabetes towards Muscle Cells Differentiation and Bioenergetics Revealed by the C2C12 Cell Model and MicroRNA Analysis.

Obesity and type 2 diabetes mellitus (T2DM) are often combined and pathologically affect many tissues due to changes in circulating bioactive molecules. In this work, we evaluated the effect of blood plasma from obese (OB) patients or from obese patients comorbid with diabetes (OBD) on skeletal muscle function and metabolic state. We employed the mouse myoblasts C2C12 differentiation model to test the regulatory effect of plasma exposure at several levels: (1) cell morphology; (2) functional activity of mitochondria; (3) expression levels of several mitochondria regulators, i.e., Atgl, Pgc1b, and miR-378a-3p. Existing databases were used to computationally predict and analyze mir-378a-3p potential targets. We show that short-term exposure to OB or OBD patients' plasma is sufficient to affect C2C12 properties. In fact, the expression of genes that regulate skeletal muscle differentiation and growth was downregulated in both OB- and OBD-treated cells, maximal mitochondrial respiration rate was downregulated in the OBD group, while in the OB group, a metabolic switch to glycolysis was detected. These alterations correlated with a decrease in ATGL and Pgc1b expression in the OB group and with an increase of miR-378a-3p levels in the OBD group.

A mitochondrial delivery system using liposome-based nanocarriers that target myoblast cells.

Mitochondrial function is reduced in skeletal muscles of many patients with systemic diseases and it is difficult to deliver medicinal substances to mitochondria in such tissue. In this study, we report on attempts to develop liposome-based carriers for mitochondrial delivery using mouse myoblasts (C2C12) by varying the lipid composition of the carriers. We found that a liposome that contains an optimal lipid modified with the KALA peptide (a cellular uptake and mitochondrial targeting device) was the most effective nanocarrier for achieving mitochondrial delivery in C2C12 cells. We also report on successful mitochondrial transgene expression using the carriers encapsulating a mitochondrial DNA vector as we previously reported.

[The effect of AdipoRon on insulin sensitivity of mouse skeletal muscle cells and its mechanism].

OBJECTIVE: To observe the effect of AdipoRon, an adiponin receptor agonist, on insulin sensitivity in mouse myoblast cell line (C2C12) and to explore its mechanism. METHODS: C2C12 was induced to differentiate into myoblasts by using horse serum. Then the cells were divided into 6 groups (9 double wells):blank control group, high dose AdipoRon group, low dose AdipoRon group, insulin group and the low dose AdipoRon with PI3K inhibitor (phosphatidylinositol 3 kinase) group and the insulin with PI3K inhibitor group. After cultured for 12 h, the supernatant was collected and glucose consumption was measured. Cell proliferation was tested by using CCK8. In the 6-well plate, C2C12 was induced to differentiate into myoblasts. The drug was incubated for 12 h and the mRNA level of GLUT4 was detected by RT-PCR. RESULTS: Compared with the blank control group, the levels of glucose consumption in high dose AdipoRon group, low dose AdipoRon group and insulin group was increased significantly (P<0.05). After adding PI3K inhibitor, the levels of glucose consumption in the above mentioned three groups were not different from that in blank control group. high dose AdipoRon group, low dose AdipoRon group and insulin group had proliferation, but only the insulin group was statistically significant (P<0.05). Compared with the control group, the levels of GLUT4 mRNA in AdipoRon high dose group, low dose AdipoRon group and insulin group were all higher than those in control group (P<0.05). After adding PI3K inhibitor, GLUT4 mRNA level was not statistically significant compared with blank control group. CONCLUSIONS: AdipoRon can increase the consumption of glucose without affecting cell proliferation, which may play a role in improving insulin sensitivity, but the specific mechanism remains to be further studied.