Bone marrow mesenchymal stem cell-derived exosomal microRNAs target PI3K/Akt signaling pathway to promote the activation of fibroblasts

BACKGROUND Fibroblast plays a major role in tendon-bone healing.Exosomes derived from bone marrow mesenchymal stem cells(BMSCs)can activate fibroblasts and promote tendon-bone healing via the contained microRNAs(miRNAs).However,the underlying mechanism is not comprehensively understood.Herein,this study aimed to identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets,and to verify their effects as well as mechanisms on fibroblasts.AIM To identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets and verify their effects as well as mechanisms on fibroblasts.METHODS BMSC-derived exosomal miRNAs data(GSE71241,GSE153752,and GSE85341)were downloaded from the Gene Expression Omnibus(GEO)database.The candidate miRNAs were obtained by the intersection of three data sets.TargetScan was used to predict potential target genes for the candidate miRNAs.Functional and pathway analyses were conducted using the Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)databases,respectively,by processing data with the Metascape.Highly interconnected genes in the protein-protein interaction(PPI)network were analyzed using Cytoscape software.Bromodeoxyuridine,wound healing assay,collagen contraction assay and the expression of COL I andα-smooth muscle actin positive were applied to investigate the cell proliferation,migration and collagen synthesis.Quantitative real-time reverse transcription polymerase chain reaction was applied to determine the cell fibroblastic,tenogenic,and chondrogenic potential.RESULTS Bioinformatics analyses found two BMSC-derived exosomal miRNAs,has-miR-144-3p and hasmiR-23b-3p,were overlapped in three GSE datasets.PPI network analysis and functional enrichment analyses in the GO and KEGG databases indicated that both miRNAs regulated the PI3K/Akt signaling pathway by targeting phosphatase and tensin homolog(PTEN).In vitro experiments confirmed that miR-144-3p and miR-23b-3p stimulated proliferation,migration and collagen synthesis of NIH3T3 fibroblasts.Interfering with PTEN affected the phosphorylation of Akt and thus activated fibroblasts.Inhibition of PTEN also promoted the fibroblastic,tenogenic,and chondrogenic potential of NIH3T3 fibroblasts.CONCLUSION BMSC-derived exosomes promote fibroblast activation possibly through the PTEN and PI3K/Akt signaling pathways,which may serve as potential targets to further promote tendon-bone healing.

Bioinspired mineral-in-shell nanoarchitectonics:Functional empowerment of mineral precursors for guiding intradentinal mineralization

Effective mineralization of biological structures poses a significant challenge in hard tissue engineering as it necessitates overcoming geometric complexities and multistep biomineralization processes.In this regard,we propose“mineral-in-shell nanoarchitectonics”,inspired by the nanostructure of matrix vesicles,which can influence multiple mineralization pathways.Our nanostructural design empowers mineral precursors with tailorable properties through encapsulating amorphous calcium phosphate within a multifunctional tannic acid(TA)and silk fibroin(SF)nanoshell.The bioinspired nanosystem facilitates efficient recruitment of mineral precursors throughout the dentin structures,followed by large-scale intradentinal mineralization both in vitro and in vivo,which provides persistent protection against external stimuli.Theoretical simulations combined with experimental studies attribute the success of intradentinal mineralization to the TA-SF nanoshell,which exhibits a strong affinity for the dentin structure,stabilizing amorphous precursors and thereby facilitating concomitant mineral formation.Overall,this bioinspired mineral-in-shell nanoarchitectonics shows a promising prospect for hard tissue repair and serves as a blueprint for next-generation biomineralization-associated materials.