The Effects Of Two Physical Properties Of Biomimetic Matrix On Macrophage Phenotype And Related Applications And Mechanisms

Macrophages participate in each stage of the acute immune response,as well as the regulation of tissue homeostasis and the orchestration of tissue repair processes.The inflammatory cascade dominated by macrophages triggered by the implantation of biomaterials,which determines the acceptance or rejection of implants through proinflammatory and anti-inflammatory polarization states.Extracellular matrix(ECM)is a complex and dynamic structure composed of hundreds of proteins,which can provide a suitable biological and physical environment for cells.Recent evidence suggests that the physical signals presented by ECM also play a important role during macrophage polarization.Therefore,this project focuses on studying the effects of two physical properties of the biomimetic matrix on the macrophages phenotype and exploring the relevant mechanisms.Part 1 The effect of matrix stiffness on macrophage phenotypes in the biofilmsThe layer-by-layer self-assembly of polylysine(PLL)and hyaluronic acid(HA)biomacromolecules is used to construct a film to explore the effect of matrix stiffness on macrophages phenotypes.In this part of the experiment,we studied the morphology,adhesion and proliferation of Raw264.7 macrophages on different substrate stiffnesses.We also detected relative expression of M1 macrophage markers(CD80 and i NOS)and M2 macrophage markers(Arg-1 and CD206).The experimental results in this section indicate that under the M0 type medium,the proliferation ability of macrophages in the high matrix stiffness group is significantly higher than that in the low matrix stiffness groups and medium stiffness groups.Under the induction of M1 medium,the adhesion of macrophages in the high matrix stiffness group was stronger than that of the low stiffness matrix.In addition,the expression of M1 macrophage markers on 400 k Pa was significantly higher than that on 200 k Pa.Under the induction of M2 medium,the expression of M2 macrophage markers on 200 k Pa was significantly higher than that on 400 k Pa.In summary,under the synergistic effect of inducing factors and matrix stiffness,low stiffness matrix is beneficial to maintain the polarization state of M2 macrophages,while a high stiffness matrix is beneficial to maintain the polarization state of M1 macrophages.Part 2 The effect of matrix viscosity on macrophage phenotypes in the calcium alginate scaffoldCalcium alginate scaffold was used to explore the effect and relevant mechanism of matrix viscosity on macrophages phenotype.In this part,we detected the proliferation and cell viability of macrophages and the expression of M2 macrophage markers(CD163 and CD206),and further explored the relevant mechanisms by means of transcriptome sequencing.The experimental results indicate that the pore size of the low viscosity group is significantly higher than that of the medium viscosity and high viscosity groups.The porosity of the high viscosity calcium alginate scaffold was significantly higher than that of the medium viscosity group,but there was no significant difference compared with the low viscosity group.Under the induction of M2 medium,the expression of M2 macrophage markers both in the low viscosity and high viscosity groups was notably higher than that in the medium viscosity group.In summary,under the synergistic effect of inducing factors and matrix viscosity,the low-viscosity and high viscosity calcium alginate scaffolds are beneficial to maintain the polarization state of M2 macrophages.The possible molecular mechanism is that the expression of the receptor CD209 on the membrane surface of macrophages increases,which promotes the down-regulation of Bcl-3,leading to the increase expression of chemokines CCL17 and CCL22.