Combination of cell signaling molecules can facilitate MYOD1-mediated myogenic transdifferentiation of pig fibroblasts

Background:Myogenic transdifferentiation can be accomplished through ectopic MYOD1 expression,which is facilitated by various signaling pathways associated with myogenesis.In this study,we attempted to transdifferentiate pig embryonic fibroblasts(PEFs)myogenically into skeletal muscle through overexpression of the pig MYOD1 gene and modulation of the FGF,TGF-β,WNT,and cAMP signaling pathways.Results:The MYOD1 overexpression vector was constructed based on comparative sequence analysis,demonstrating that pig MYOD1 has evolutionarily conserved domains across various species.Although forced MYOD1 expression through these vectors triggered the expression of endogenous muscle markers,transdifferentiated muscle cells from fibroblasts were not observed.Therefore,various signaling molecules,including FGF2,SB431542,CHIR99021,and forskolin,along with MYOD1 overexpression were applied to enhance the myogenic reprogramming.The modified conditions led to the derivation of myotubes and activation of muscle markers in PEFs,as determined by qPCR and immunostaining.Notably,a sarcomere-like structure was observed,indicating that terminally differentiated skeletal muscle could be obtained from transdifferentiated cells.Conclusions:In summary,we established a protocol for reprogramming MYOD1-overexpressing PEFs into the mature skeletal muscle using signaling molecules.Our myogenic reprogramming can be used as a cell source for muscle disease models in regenerative medicine and the production of cultured meat in cellular agriculture.

Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.

The aqueous extract of brucea javanica reduces tumorigenicity of human lung cancer tumorspheres

Aim:Therapy to overcome drug resistance by modulating epidermal growth factor receptor(EGFR)is a viable approach to suppress the proliferation of human non-small cell lung cancer(NSCLC)cells.A previous study demonstrated that the seeds of an aqueous Brucea javanica(BJ)(L.)Merr(Simaroubaceae)extract containing quassinoid mixtures effectively inhibited the growth and alleviated tumorigenesis in H1975 cells of NSCLC by targeting T790M/L858R EGFR.This study aimed to further determine whether the aqueous BJ extract affects the enriched H1975 spheroids in suspension culture and mouse xenograft tumor models.Methods:The spheroids of NSCLC adenocarcinoma H1975 cells were enriched in a serum-free media.The growth rate of sphere propagation by aqueous BJ extract was determined in suspended culture and in colony-formation assay.BJ extract was fed orally to nude mice bearing xenograft tumors.The resected tumors were analyzed by hematoxylin and eosin staining,terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay,and proliferating cell nuclear antigen assessment.Various markers were used to determine the pluripotency of tumors from mice treated with different concentrations of BJ extract.Results:BJ extract was demonstrated to be effective against the propagation of the enriched spheroids.In animal models,oral administration of the aqueous BJ extract reduced spheroid tumorigenicity.The alleviated growth of the established xenograft tumors can be attributed to the reduced drug resistance and induced apoptosis without distinct adverse effects.More evidence supports activated apoptotic death attenuated spheroid stemness of tumors.Conclusion:As an effective treatment regime to assuage lung cancer,the indigenous BJ extract promises to obliterate drug resistance and the growth of cancer stem cell tumors from NSCLC cells harboring T790M/L858R EGFR.