Alcalase Potato Protein Hydrolysate-PPH902 Enhances Myogenic Differentiation and Enhances Skeletal Muscle Protein Synthesis under High Glucose Condition in C2C12 Cells

Sarcopenia is an aging associated disorder involving skeletal muscle atrophy and a reduction in muscle strength, and there are no pharmaceutical interventions available thus far. Moreover, conditions such as hyperglycaemia are known to further intensify muscle degradation. Therefore, novel strategies to attenuate skeletal muscle loss are essential to enhance muscle function and thereby improve the quality of life in diabetic individuals. In this study, we have investigated the efficiency of a potato peptide hydrolysate PPH902 for its cytoprotective effects in skeletal muscle cells. PPH902 treatment in C2C12 cells showed the dose-dependent activation of the Akt/mTOR signalling pathway that is involved in skeletal myogenesis. According to Western blotting analysis, PPH902 induced the phosphorylation of Akt, mTOR proteins and induced the myogenic differentiation of C2C12 myoblasts in a differentiation medium. The phosphorylation myogenic transcription factor Foxo3A was also found to be increased in the cells treated with PPH902. In addition, treatment with PPH902 ameliorated the high glucose induced reduction in cell viability in a dose-dependent manner. Moreover, the number of myotubes in a differentiation medium reduced upon high glucose challenge, but treatment with PPH902 increased the number of differentiated myotubes. Further, the phosphorylations of AMPK and mitochondrial-related transcription factors such as PGC-1α were suppressed upon high glucose challenge but PPH902 treatment restored the protein levels. We demonstrate, for the first time, that a specific potato peptide has a therapeutic effect against sarcopenia. In addition, PPH902 improved the myogenic differentiation and their mitochondrial biogenesis and further improved myogenic protein and inhibited muscle protein degradation in C2C12 cells challenged under a high glucose condition.

Chondrogenic Potential of Human Dental Pulp Stem Cells Cultured as Microtissues

Several tissue engineering stem cell-based procedures improve hyaline cartilage repair. In this work, the chondrogenic potential of dental pulp stem cell (DPSC) organoids or microtissues was studied. After several weeks of culture in proliferation or chondrogenic differentiation media, synthesis of aggrecan and type II and I collagen was immunodetected, and SOX9, ACAN, COL2A1, and COL1A1 gene expression was analysed by real-time RT-PCR. Whereas microtissues cultured in proliferation medium showed the synthesis of aggrecan and type II and I collagen at the 6th week of culture, samples cultured in chondrogenic differentiation medium showed an earlier and important increase in the synthesis of these macromolecules after 4 weeks. Gene expression analysis showed a significant increase of COL2A1 after 3 days of culture in chondrogenic differentiation medium, while COL1A1 was highly expressed after 14 days. Cell-cell proximity promotes the chondrogenic differentiation of DPSCs and important synthesis of hyaline chondral macromolecules.

Different p53 Genotypes Regulate PPARγ Post-Translational Modification in The Adipogenic Differentiation of Cancer Cells

Background: Our previous studies confirmed that high concentrations of cobalt chloride (CoCl2) can induce the formation of polyploid giant cancer cells (PGCCs). PGCCs have the properties of cancer stem cell. In this study, we demonstrate that PGCCs can be induced to differentiate into adipose in vitro and in vivo. In addition, the molecular mechanism of adipogenic differentiation of PGCCs with daughter cells was investigated by detecting the expression of adipocyte differentiation related proteins in mutant and wild-type p53 cancer cell lines. Methods: HEY and MDA-MB-231 control cells and PGCCs with daughter cells were cultured with adipogenic differentiation medium and the cell cycle was detected by flow cytometry. The expression of adipocyte differentiation related proteins, and P300 histone acetyltransferase activity were compared before and after adipogenic differentiation. Immunoprecipitation was used to analyze the post-translational modification of peroxisome proliferator-activator receptor-γ (PPARγ) and P53 in HEY and MDA-MB-231 control cells and PGCCs with daughter cells cultured with adipogenic differentiation medium. Animal xenograft models were used to study the adipogenic differentiation of PGCCs with daughter cells.Results: Dexamethasone, rosiglitazone, insulin, and 3-isobutyl-1-methylxanthine (IBMX) can force the trans-differentiation of PGCCs into post-mitotic and functional adipocytes. Activation of PPARγ is a critical step in the process of adipogenic differentiation. The expression levels of p-CREBser133, PPARγ, C/EBPα, C/EBPβ were higher in PGCCs with daughter cells after adipogenic differentiation compared with those without adipogenic differentiation in HEY and MDA-MB-231. P53 regulates the acetylation and phosphorylation of PPARγ and the expression of P300- Acetyl-PPARγ(Lys)- FABP4 and ERK- Phospho-PPARγ (Ser112)-FABP4 depended upon the genotype of p53 in HEY and MDA-MB-231 cells after cultured with adipogenic differentiation medium. The invasion and migration abilities of PGCCs with their daughter cells after adipogenic differentiation decreased compared with those cells without adipogenic differentiation.Conclusion: P300-P53-ERK-CREB-PPARγ-CEBPα/β-FABP4 pathway may participate in the adipogenic differentiation of HEY, MDA-MB-231 PGCCs with daughter cells, which associated with genotype of p53.

Scaffold-Free Engineering of Human Cartilage Implants

Objective Despite new strategies in tissue engineering, cartilage repair remains a major challenge. Our aim is to treat patients with focal lesions of articular cartilage with autologous hyaline cartilage implants using a scaffold-free approach. In this article, we describe experiments to optimize production of scaffold-free cartilage discs. Design Articular chondrocytes were expanded in vitro, seeded in transwell inserts and redifferentiated using established chondrogenic components. Experimental variables included testing 2 different expansion media, adding bone morphogenetic protein 2 (BMP2), insulin-like growth factor 1 (IGF1), growth/differentiation factor 5 (GDF5), or fibroblast growth factor 18 (FGF18) to the differentiation medium and allowing the disc to float freely in large wells. Cartilage discs were analyzed by weight and thickness, real-time RT-qPCR (reverse transcriptase qualitative polymerase chain reaction), fluorescence immunostaining, transmission electron microscopy, second harmonic generation imaging, and measurement of Young’s modulus. Results Addition of BMP2 to the chondrogenic differentiation medium (CDM) was essential for stable disc formation, while IGF1, GDF5, and FGF18 were redundant. Allowing discs to float freely in CDM on a moving platform increased disc thickness compared with discs kept continuously in transwell inserts. Discs cultured for 6 weeks reached a thickness of almost 2 mm and Young’s modulus of >200 kPa. There was abundant type II collagen. Collagen fibrils were 25 nm thick, with a tendency to be organized perpendicular to the disc surface. Conclusion Scaffold-free engineering using BMP2 and providing free movement in CDM produced firm, elastic cartilage discs with abundant type II collagen. This approach may potentially be used in clinical trials.

Groundnut (Apios americana Medik) Extract Enhances the Osteoblast Differentiation of MC3T3-E1 Cells

The effects of groundnut ( Apios americana Medik) extract on osteoblast differentiation were examined using MC3T3-E1 cells. MC3T3-E1 cells were treated with the crude extract along with other differentiating reagents. The alkaline phosphatase (ALP) activity of cells cultured in a differentiation medium supplemented with 0.01% crude groundnut extract was 1.5‐1.6 times higher than that of cells cultured in a differentiation medium without the extract. Crude groundnut extract was further separated into aqueous and methanol fractions. The methanol fraction enhanced ALP activity, osteocalcin, integrin-binding sialoprotein, and type I collagen expression, and calcium mineralization. Conversely, the aqueous fraction did not show such effects. Groundnut extract may enhance osteoblast differentiation, and this effect is likely conferred by water insoluble substance(s).

Ciglitazone Increases Adiponectin and Adipogenic Gene Expression in Bovine Skeletal Muscle Satellite Cells

Background: Ciglitazone is a member of the thiazolidinedione (TZD) family, and specifically binds to peroxisome proliferator-activated receptor-γ (PPARγ) , thereby promoting adipocyte differentiation. We hypothesized that ciglitazone as a PPARγ ligand in the absence of an adipocyte differentiation cocktail would increase adiponectin and adipogenic gene expression in bovine satellite cells (BSC).Methods: Muscle-derived bovine satellite cells were isolated from six, 18-month-old Yanbian Yellow Cattle. The BSC were cultured for 96 h in differentiation medium containing 5 µM ciglitazone (CL), 10 µM ciglitazone (CM), or 20 µM ciglitazone (CH). Control (CON) BSC were cultured only in differentiation medium (containing 2% horse serum).Results: The presence of myogenin, desmin, and paired box 7 (Pax7) proteins were confirmed in the BSC by immunofluorescence staining. The CL, CM, and CH treatments produced higher concentrations of triacylglycerol and lipid droplet accumulation in myotubes than those of the CON treatment. Ciglitazone treatments significantly increased the relative expression of PPARγ , CCAAT/enhancer-binding protein alpha (C/EBPα), C/EBPβ, fatty acid synthase stearoyl-CoA desaturase (SCD) and perilipin 2. Ciglitazone treatments increased gene expression of paired box 3 (Pax3) and Pax7 and decreased expression of myogenic differentiation-1, myogenin, myogenic regulatory factor-5 (MRF5), and MYF4 (P < 0.01). Adiponectin concentration caused by ciglitazone treatments was significantly greater than CON (P < 0.01). RNA sequencing showed that 281 differentially expressed genes (DEGs) were found in the treatments of ciglitazone. DEGs gene ontology (GO) analysis showed that the top 10 GO enrichment significantly changed the biological processes such as protein trimerization, negative regulation of cell proliferation, adipocytes differentiation, and cellular response to external stimulus. KEGG pathway analysis showed that DEGs were involved into p53 signaling pathway, PPAR signaling pathway, biosynthesis of amino acids, TNF signaling pathway, non-alcoholic fatty liver disease (NAFLD), PI3K-Akt signaling pathway, and Wnt signaling pathway.Conclusion: These results indicate that ciglitazone acts as PPARγ agonist, effectively increasing the adiponectin concentration and adipogenic gene expression, and stimulating the conversion of BSC to adipocyte-like cells in the absence of adipocyte differentiation cocktail.

Controlling Cellular Arrangements via Stretched Bioprinting

Bioprinting is a common method to replicate geometrical architecture of native tissues. However, it usually fails to modulate cellular arrangements, which is critical for the tissue’s functionality. To our knowledge, no method has successfully addressed this challenge. Here, we report a method of controlling cellular orientation during the bioprinting process by integrating a stretch process into a modified bioprinting frame. We demonstrate that the cellular orientation is a result of cells’ sensing and responding to the tensile stress, instead of shear stress or topographical patterns. Moreover, our method shows a potent capability to induce myoblast differentiation, fusion and maturation without the presence of differentiation medium. As a potential clinical application, we demonstrate that aligned myofibers directly printed onto injured muscle in vivo, can not only repair the structure of damaged tissue, but also recover the muscle functionalities effectively. This study shows that the new method can produce tissues with precise control of cellular arrangements and more clinically viable functionalities.Significance StatementDue to no method could reproduce the exact cellular arrangements of native tissues in engineered tissues, tissue engineering facing difficult in fabricating 3D tissues that possess desirable biological and mechanical functionalities for biomedical applications. For the first time, we report a method of controlling cellular orientation during 3D bio-printing process. This method can be used to produce engineered tissues with controlled cellular arrangement with several different cell types. Moreover, this method shows a potent capability of fabricating fully mature and aligned myofibers in vitro in the absence of differentiation medium. As potential clinical applications, with this method, engineered tissues could be directly printed in vivo with high efficacy of tissue repair and function recovery.

Changes in abscisic acid metabolism in relation to the maturation of grapevine (Vitis vinifera L., cv. Mencía) somatic embryos

Background Somatic embryogenesis in grapevines is a complex process that depends on many physiological and genetic factors. One of its main limitations is the process of precocious germination of the somatic embryos in differentiation medium. This process lowers plant conversion rates from the somatic embryos, and it is probably caused by a low endogenous abscisic acid (ABA) content. Results Precocious germination of the somatic embryos was successfully avoided by culturing grapevine cv. Mencía embryogenic aggregates over a semipermeable membrane extended on top of the differentiation medium. The weekly analysis of the endogenous ABA and ABA-glucosyl ester (ABA-GE) contents in the aggregates showed their rapid accumulation. The expression profiles of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), 8′-hydroxylase (VvHyd2), UDP-glucosyltransferase (VvUGT) and β-glucosidase (VvBG2) genes in grapevine revealed that the occurrence of a first accumulation peak of endogenous ABA in the second week of culture over the semipermeable membrane was mainly dependent on the expression of the VvNCED1 gene. A second increase in the endogenous ABA content was observed in the fourth week of culture. At this point in the culture, our results suggest that of those genes involved in ABA accumulation, one (VvNCED1) was repressed, while another (VvBG2) was activated. Similarly, of those genes related to a reduction in ABA levels, one (VvUGT) was repressed while another (VvHyd2) was activated. The relative expression level of the VvNCED1 gene in embryogenic aggregates cultured under the same conditions and treated with exogenous ABA revealed the significant downregulation of this gene. Conclusions Our results demonstrated the involvement of ABA metabolism in the control of the maturation of grapevine somatic embryos cultured over a semipermeable membrane and two important control points for their endogenous ABA levels. Thus, subtle differences in the expression of the antagonistic genes that control ABA synthesis and degradation could be responsible for the final level of ABA during the maturation of grapevine somatic embryos in vitro. In addition, the treatment of somatic embryos with exogenous ABA suggested the feedback-based control of the expression of the VvNCED1 gene by ABA during the maturation of grapevine somatic embryos.