Study On The Anti-inflammatory Activity Of Human Placental Mesenchymal Stem Cells And Their Exosomes

Inflammation is a common clinical disease,which is a response process of tissue damage and repair when the body is stimulated by pathogenic factors.Studies have confirmed that when there is inflammation in the body,a variety of inflammatory cells and cytokines secreted by inflammatory cells work together to form a very complex biological effect.Inflammatory response has two sides,moderate inflammation is beneficial to repair the body damage,but the maladjusted inflammatory response will lead to many diseases.Therefore,it is particularly important to balance the inflammation level in the body.Macrophages are very important in the body,which participate in the immune regulation of the body by secreting a variety of factors.Macrophages can be polarized into different phenotypes by different stimuli,which can play pro-inflammatory or anti-inflammatory roles.Therefore,the study of inflammation can be translated into the study of macrophage polarization.Mesenchymal stem cells(MSCs)related to the regulation of inflammation has been reported.Human placental mesenchymal stem cells(HPL-MSCs),compared with other MSCs,have the characteristics of a wide range of sources and convenient materials.At the same time,it also avoids the problem of the placenta becoming medical waste disposal.If it can be used for medical research,it is of great significance.The essence of exosomes is the vesicles secreted by cells.Exosomes derived from MSCs have immune activity and participate in the immune regulation of the body.Its regulatory effect has also been confirmed in some disease models,which has good clinical application value.Based on previous studies,this paper starts from HPL-MSCs and their exosomes to explore their anti-inflammatory activity and possible immunomodulatory mechanisms.This research mainly includes the following contents:(1)HPL-MSCs were separated by the tissue block method,and higher purity cells were obtained after magnetic bead positive sorting.The cells were identified by morphological observation,flow cytometry identification of cell surface markers,and in vitro adipogenic osteogenic differentiation experiments.It was confirmed that the cells extracted from the placenta were MSCs.(2)In order to establish an inflammatory cell model,lipopolysaccharide(LPS)was used to act on macrophages to polarize them into M1 phenotype.Through co-culturing of HPL-MSCs and macrophage,the effect on inflammation was explored.After ELISA,FCM,WB,q RT-PCR and other experiments,the secretion of inflammatory factors in the co-culture system was studied in the protein level and gene level respectively.The results showed that HPL-MSCs can inhibit the M1 polarization of macrophages,and reduce the secretion of inflammatory factors,such as IL-6,TNF-α and IL-1β.Through WB experiment,results indicate that HPL-MSCs can participate in immune regulation through the NF-κB signaling pathway.(3)Lipopolysaccharide(LPS)was acted on A549 cells to establish an inflammatory disease-acute lung injury model.HPL-MSCs were co-cultured with A549 cells,results showed that HPL-MSCs treatment can effectively improve the release of inflammatory factors in the system,thereby improving lung injury.WB experiments confirmed that this may be related to the regulation of the NF-κB signaling pathway.(4)The HPL-MSCs-derived exosomes were separated by ultra-high-speed centrifugation,and they were characterized by transmission electron microscopy,particle size analysis,and analysis of exosomal marker proteins.Lipopolysaccharide(LPS)was used to act on macrophages,polarize them into M1 phenotype,and establish a cellular inflammation model.It was found that exosomes can reduce the M1 polarization of macrophages and achieve the goal of improving inflammation.The conclusion of this study is that both HPL-MSCs and their exosomes have anti-inflammatory effects.