Exposure To Blue Light Stimulates The Proangiogenic Capability Of Exosomes Derived From Human Umbilical Cord Mesenchymal Stem Cells

BackgroundExosomes are a class of extracellular vesicles with bilayer membrane structure,rich in miRNAs,mRNAs and proteins,which are mainly responsible for material transport and information transmission between cells.Exosomes derived from human umbilical cord mesenchymal stem cells have the ability of proangiogenic.In this study,we exposed mesenchymal stem cells to time-controllable and intensity-controllable light stimulation,and then detected and analyzed their proliferation,migration and angiogenesis.The results showed that irradiation with 455 nm monochromatic blue light at 300 ?W/cm2 intensity for 120 min could promote the proliferation and migration of mesenchymal stem cells.Further co-cultured them with human umbilical vein endothelial cells revealed that characteristic blue light significantly promoted the proliferation,migration and angiogenesis of endothelial cells,in which the miR-135b-5p and miR-499a-3p in exosomes played an important regulatory role in this process.ObjectiveIn this study,we explored the ability of characteristic blue light to promote angiogenesis of stem cell-derived exosomes and analyzed the preliminary molecular mechanism.Methods1.Light stimulation of cells:We selected monochromatic blue light(455 nm)and red light(638 nm)to validate the stimulation effect of light on MSCs and HUVECs.2.Proliferation,migration and angiogenesis experiments:The proliferation,migration and angiogenesis of MSCs and HUVECs(co-cultured with MSCs)were detected by EdU(5-ethynyl-2'-deoxyuridine)incorporation,wound healing and angiogenesis analysis.3.Determination the proangiogenic capability of exosomes derived from MSCs under blue light by Matrigel Plug Model:The matrigel mixed with exosomes was injected into the subcutaneous groin of mice,and after embolization,it was taken out and analyzed by hematoxylin and eosin staining and immunofluorescence staining.4.Determination the proangiogenic capability of exosomes derived from MSCs under blue light by Burn Model of mice:A scalded skin area about 1 cm in diameter was formed on the back of mice by boiling water and rescued by exosomes.After 0,3,5 and 7 days of treatment,the skin tissues were analyzed by hematoxylin and eosin staining and immunofluorescence staining.5.Extraction,isolation and identification of exosomes derived from MSCs:The culture medium supernatant of MSCs was collected,and the exosome was prepared by QIAGEN exoEasy Maxi kit,and its existence was confirmed by transmission electron microscope and the identification of characteristic antibody.6.The expression of miRNAs in cells and exosomes:The miRNAs in cells and exosomes were extracted by TRIzol,and the expression of miR-135b-5p and miR-499a-3p were quantified by Real-Time PCR.Results1.MSCs expressed kinds of photoreceptors such as RHO,RRH,OPN IS W,OPN4 and OPN5.2.455 nm blue light stimulation with a duration of 120 minutes and power densities of 300 ?W/cm2 can accelerate the proliferation,migration and angiogenesis of HUVECs(co-cultured with MSCs).3.Characteristic blue light illumination of MSC-derived exosomes promote HUVECs'infiltration and angiogenesis in matrigel.4.Characteristic blue light illumination of MSC-derived exosomes promote the angiogenesis of endothelial cells in the wound site,and are beneficial to the wound healing.5.Characteristic blue light stimulation promotes miR-135b-5p and miR-499a-3p decreased MEF2C protein expression in MSC-derived exosomes.ConclusionsIn this study,we found that 455 nm monochromatic blue light stimulation with a duration of 120 minutes and power densities of 300 ?W/cm2 could effectively improve the proangiogenic capability of exosomes derived from human umbilical cord mesenchymal stem cells.Characteristic blue light-treated MSC-derived exosomes activate HUVECs' proliferation,migration and angiogenesis through up-regulation miR-135b-5p and miR-499a-3p,and it provides scientific clues for tissue regeneration and repair.