Research On Immunomodulatory Effect Of Human Wharton's Jelly And Endometrium Mesenchymal Stem Cells

With the development of medicine science, transplantation of organs, tissues and cells has become the common and effective way to treat many disease. However, human body has very perfect defense mechanism, and exogenous graft can be recognized by the defense system firstly, then the immune system can be activated and cause rejection to attack, destroy and eliminate the graft. Immune rejection has great destructive to the human body. Exogenous graft will be injured when the rejection occured, severely, it will cause transplanted organs and tissues lose function and even made the life endanger. In addition, immune system diseases are also a serious problem which puzzled medical workers. Autoimmune disease is a disease of immune response disorder, which body immune system attacks autoantigen, causes tissue damage and organ dysfunction in diseases with high morbidity and mortality rates, and it has no effective treatment until now.The primary function of immunosuppressive agents is to reduce the body rejection for foreign objects to make them coexistence peacefully, so it plays an important role in the clinical treatment of organ or tissue transplantition and autoimmune diseases. However, the side effect of immunosuppressive agents, including infection and tumor incidence increased caused by immunosuppression presented such daunting challenges to the clinical treatment. So it has important practical significance to look for a safer and more effective treatment method.Mesenchymal stem cells are a class of mesodermal pluripotent stem cells which have self-renewal and multilineage differentiation potential that can be used as important seed cells for tissue engineering and cell transplantation. A large number of studies have shown that MSCs also have low immunogenicity and immune regulation, which can effectively inhibit the allogeneic immune rejection, extend the graft survival time and improve the success rate of transplantation. Other studies have shown that MSCs also have a good therapeutic effect in graft-versus-host disease and autoimmune diseases which are caused by hematopoietic stem cell transplantation. However, due to various reasons, the study of MSCs mainly focused on bone marrow mesenchymal stem cells, but bone marrow mesenchymal stem cells which are obtained by the traumatic method also declined in the quantity and quality in ageing people. So it is necessary for clinical application to search new types of stem cells which have a wide range of source and are easy to be collected, especially no ethics issue.Recent studies have shown that human umbilical cord Wharton s Jelly and menstrual blood-derived mesenchymal cells are a new type of seed cells with a high degree of self-renewal capacity and multi-differentiation potential.Compared with the BMSCs, WJCs and ERCs have lots of advantages. WJCs and ERCs not only have a wider range of source but also are easily to be collected without obvious ethics problems. Additionally, it also has stronger proliferation capability. Therefore, it can become a new source of MSCs and has good application prospects.Our research group took lead in the successful isolated culture of WJCs and ERCs, and found that the surface marker expression of WJCs and ERCs is almost the same as BMSCs', indicating WJCs and ERCs may have similar biological characteristics to BMSCs. Therefore, studing the immune regulation of WJCs and ERCs has important practical significance for clinical application and basic research.As followed below, this essay was divided into two parts. PartⅠ:Isolation, culture and identification of WJCs and ERCs, PartⅡ:The immune regulation research of WJCs and ERCs.PartⅠ:The human umbilical cords used in this subject were supplied by the Department of Obstetrics, First Affiliated Hospital, Zhengzhou University, Peripheral blood obtained from healthy volunteers. WJCs were separated by culture of tissue adherence. ERCs were separated by density gradient centrifugation. WJCs and ERCs morphous was observed with inverted microscope and the flow cytometer was performed to examine the expression of cell surface molecules. Futhermore, the P1, P3, P5 WJCs and ERCs growth activity were tested by CCK-8 kit. The results showed that WJCs can be isolated successfully by tissue culture method from human umbilical cord Wharton's jelly and ERCs can be isolated by density gradient centrifugation from menstrual blood. The result of FCM showed that the WJCs and ERCs express MSCs markers. Low expression of HLA-ABC while HLA-DR was negative, indicating that they only have low immunogenicity. Growth curve results showed that the P1, P3, P5 WJCs and ERCs have good growth vigor.PartⅡ:We used the P3 WJCs and ERCs which have strong proliferation, put WJCs, ERCs and their culture supernatant co-cultured with the mouse spleen lymphocytes and human peripheral blood lymphocytes simulated by PHA respectively to observe the effect of WJCs, ERCs and their culture supernatant to proliferation of homologous and heterologous lymphocyte. Then, expression of cytokines including human transforming growth factor (TGF-β1)and interferon-y (IFN-y) was aslo evaluated by ELISA detection kit. These experimentations were used to study the immune regulation mechanisms of WJCs and ERCs from the levels of cytokines secretion. The results showed that WJCs, ERCs and their supernatant can inhibite the proliferation of mouse spleen lymphocytes and human peripheral blood lymphocyte induced by PHA. IFN-y secretion of human peripheral blood lymphocytes can suppressed by WJCs and ERCs significantly. In addition, WJCs and ERCs may secrete TGF-β1, but human peripheral blood lymphocytes may secrete this cytokines too and the secretion of TGF-β1 more than WJCs, ERCs and human peripheral blood lymphocytes co-cultured group.In a word, WJCs and ERCs were isolated successfully from human umbilical cord Wharton's jelly and menstrual blood this study successfully isolated MSCs from Wharton's jelly and menstrual blood respectively, the immunephenotype of WJCs and ERCs is similar to BMSCs, and compared with BMSCs, they have a stronger proliferation capacity, so they can be used as a new kind of MSCs sources. The study found that WJCs and ERCs have a special immune regulation on both homologous and heterologous lymphocytes; the mechanism may be related to direct contact between cells and the secretion of some soluble molecule. It can be providing a theoretical basis to reduce immune rejection caused by allograft and treat autoimmune diseases.