MicroRNA’s Regulatory Roles In The Interfacial Behaviors Of Mesenchymal Stem Cells

Biomaterials-cells interaction is one of the most important aspects of tissueengineering. As the scaffold supports growth and differentiation of seed cells as well asregeneration of tissue, the chemical nature and topography of biomaterials play vitalroles in the cellular interfacial behaviors. Here we studied the interfacial behaviorsinduced by10μm wide grooved pattern and the underlyingmicroRNA’s regulation roles.Rat bone marrow mesenchymal stem cells (MSCs) exhibited different behaviors ongrooved PHBHHx substrate and planar PHBHHx substrate. When cultured on groovedPHBHHx substrate, MSCs aligned along the direction of grooves and exhibited fibrousphenotype; while cultured on planar PHBHHx substrate, MSCs randomly attached tothe substrate and exhibited more spreading shape. Also, the adhesion formation inMSCs cultured on micro-grooved substrate showed more immature appearance andmore amount than those on planar PHBHHx substrate. F-actin in MSCs on groovedsubstrate distributed in the cell periphery, while in MSCs on planar substrate, F-actinpenetrated whole cell body. Global marker genes expression analysis revealed theadhesion, proliferation, differentiation and apoptosis behaviors of MSCs response to thegrooved PHBHHx substrate. Compared to MSCs cultured on planar PHBHHx substrate,MSCs on grooved PHBHHx substrate showed increased expression ofosteogenesis-related marker genes including cbfa1, col1a1and bmp2, and decreasedexpression of adipogenesis-related genes including lpl, des and acta2andmyogenesis-related genes of myh11and nse, as well as vcl, vinculin encoding gene.These variations may due to the aligned micro-grooves on the PHBHHx substrate.The microRNA microarrays discovered18microRNA differentially-expressed inthe MSCs cultured on grooved PHBHHx substrate. Through target genes prediction andliterature investigation, these18microRNA might act with various genes in thesignaling transduction network, resulted in the ostegenenesis behavior. Similar to thetopography induced osteogenic behavior, co-transfection of the osteogenic microRNAcombination (miR-140, miR-214, miR-320, miR-351and miR-674-5p) couldcomparably stimulate the expression of bone marker genes, with more physiologicalsignificance. Thus, microRNA plays vital roles in the interfacial behavior variations induced by micro-grooves，in a more robust way.Based on above results, this study also proposed the utilization of multiplemicroRNAs in the construction of intracellular molecular pathway for cell migration,which is an important aspect in tissue engineering.In conclusion, this paper elucidated the important roles of microRNA inmicroenvironment triggered cell behaviors, and provided clues for the PHA biomedicalmaterials development as well as the seed cell reconstruction.