Layer-by-layer assembly of procyanidin and collagen promotes mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo

Collagen,commonly used in tissue engineering,is widespread in various tissues.During bone tissue regeneration,collagen can stimulate the cellular response and determine the fate of cells.In this work,we integrated collagen type II with procyanidin(PC)onto an implant coating by applying a layer-by-layer technique to demonstrate that collagen and PC can participate in the construction of new biomaterials and serve as multifunctional components.The effects of PC/collagen multilayers on the viability of cocultured bone marrow mesenchymal stem cells(BMSCs)were analyzed by cell counting kit-8 analysis and phalloidin staining.The reactive oxygen species level of BMSCs was revealed through immunofluorescent staining and flow cytometry.Osteogenesis-related genes were detected,and in vivo experiment was performed to reveal the effect of newly designed material on the osteogenic differentiation of BMSCs.Our data demonstrated that in BMSCs PC/collagen multilayers accelerated the proliferation and osteogenic differentiation through Wnt/β-catenin signaling pathway and enhanced bone generation around the implant in the bone defect model of rabbit femurs.In summary,combination of collagen and PC provided a new sight for the research and development of implant materials or coatings in the future.

Macrophage migration inhibitory factor protects bone marrow mesenchymal stem cells from hypoxia/ischemia-induced apoptosis by regulating lncRNA

Objective:This research was performed to explore the effect of macrophage migration inhibitory factor(MIF)on the apoptosis of bone marrow mesenchymal stem cells(BMSCs)in ischemia and hypoxia environments.Methods:The cell viability of BMSCs incubated under hypoxia/ischemia(H/I)conditions with or without pretreatment with MIF or triglycidyl isocyanurate(TGIC)was detected using cell counting kit-8(CCK-8)analysis.Plasmids containing long noncoding RNA(lncRNA)maternally expressed gene 3(MEG3)orβ-catenin small interfering RNA(siRNA)were used to overexpress or downregulate the corresponding gene,and the p53 signaling pathway was activated by pretreatment with TGIC.The influences of MIF,overexpression of lncRNA MEG3,activation of the p53 signaling pathway,and silencing ofβ-catenin on H/I-induced apoptosis of BMSCs were revealed by western blotting,flow cytometry,and terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick-end labeling(TUNEL)staining.Results:From the results of CCK-8 assay,western blotting,and flow cytometry,pretreatment with MIF significantly decreased the H/I-induced apoptosis of BMSCs.This effect was inhibited when lncRNA MEG3 was overexpressed by plasmids containing MEG3.The p53 signaling pathway was activated by TGIC,andβ-catenin was silenced by siRNA.From western blot results,the expression levels ofβ-catenin in the nucleus and phosphorylated p53(p-p53)were downregulated and upregulated,respectively,when the lncRNA MEG3 was overexpressed.Through flow cytometry,MIF was also shown to significantly alleviate the increased reactive oxygen species(ROS)level of BMSCs caused by H/I.Conclusions:In summary,we conclude that MIF protected BMSCs from H/I-induced apoptosis by downregulating the lncRNA MEG3/p53 signaling pathway,activating the Wnt/β-catenin signaling pathway,and decreasing ROS levels.