The Influence Of AIRE To Treg Mediated By TLR4 And Notch1

The explain of Immune tolerance is the immune system of organism contact a special antigen, then display the phenomenon of specific non-responsiveness to this antigens, this is the specific form of immune response. If the self-tolerance is broken down, it will lead to autoimmune diseases. The maintance of self-tolerance are carried out through central and peripheral tolerance mechanisms. And the thymus is the main site in inducing T lymphocytes central tolerance. T lymphocytes central tolerance is complete by negtive selection and positive selection. By two selecte, most autoreactive T lymphocytes are deleted by central tolerance mechanism, there are also a few cells can escape from thymus and migrate to peripheral circulation. But only 3–5% of the general population suffers from autoimmune diseases. It must be several peripheral tolerance mechanisms can prevent the diseases. Generally the peripheral tolerance mechanisms include clonal ignorance, anergy, and deletion. Since CD4+CD25+ regulatory T cells are identified and characterized with immune suppresion ability by Sakaguchi and his collegors in 1995, more and more researchers pay close attention to the key role of this subsets in peripheral immunotolerance. But so far there are many questions about its generation and function.Autoimmune regulator(AIRE)is a kind of transcript factor, specially expressed on medulla thymic epithelial cells and macrophages and dendritic cells in peripheral spleen, lymph nodes. The single mutation of AIRE will lead autoimmune polyglandular syndrome typ1(APS1), also named Autoimmune Polyendocrinopathy -Candidiasis-Ectodermal Dystrophy Phenotype(APECED), which mediated by autoimmune response and characterized with multi-organs damage. The clinical features is autoimmune diseases affected multi-glanders. Its manifestions include addison's disease, hypoparathyroidism, thyroid disorder, diabetes, autoimmune hepatitis and so on. Recently reports suggest AIRE expressed in thymus can regulate the expression of tissue specific antigens on mTECs, thus play a critical role in negetive seletion and deletion of autoreactive T cells of central tolerance. And it leads to the autoimmunity in APS1 patients. However, the role of AIRE in peripheral immunotolerance is unclear. At the same time besides the autoimmunity, APS1 patients often suffer from the immune deficiency with candidiasis. But this deficiency can not explained by central tolerance. Therefore we suppose that the peripheral role of AIRE may be the reason of candidiasis.Toll like receptors are a family of pattern recognition receotors which express on APCs such as Macrophages and DCs. On one hand, they can recognize different groups of pathogens such as bacteria,virus, fungus, and so on, then activate natural and specific antigen immune response, function as immune defence, on the another hand, they can recongnize and scavenge self aged and pathological changed cell, function as immune stability. Abnormal expression of TLRs, not only will cause the sacvenge inability of such pathogenic microorganism-immune deficiency, but also induce the autoimmune disease for the inability of scanvenge of the self aged and pathological changed cell. Some reports says, TLR4 can recognize Candida albicans, sustain the organism tolerance. So, Weather the function of periphery tolerance of AIRE expressed on the APC was achieved by the the regulation of the expression of the TLR4 become one of the target of this study.Notch was first designste one of the mutation form in drosophila, It's a quite conservative trans-membrane receptor protein on evolution. Have functions in the growth of many organs and cells. Serve as receptor, it can interaction with the ligand expressed on the adjacent cell to achieve the signal transduction.through this to determain the destiny of many cell in the animal development precess. Notch1 is one of Notchs receptor. Some study have confirm,Notch1 was expressed in the Macrophage,Notch1 ligand Jagged1 expressed on the Treg cell,so deduces Notch signal pathway functions in the development and regulation of the Treg cell. So, Weather the function of periphery tolerance of AIRE expressed on the APC was achieved by the the regulation of the expression of the Notch1 become one of the target of this study.In this part. Establish the mouse macrophage model through the AIRE transfection, Explore the expression of the AIRE on the perepheral macrophage under physiological status could or not regulate the expression of TLR4 and/or Notch1,influence the maturity stage of the APC, then regulated function CD4+CD25+ Treg,exert the peripheral tolerance function,For this, we carry out 3 researches as below:1. The influence to CD4+CD25+Treg by AIRE tranfected RAW264.7cell.To investigate the machinism of AIRE in the perephral tolerance,,detect its influence to CD4+CD25+Treg cell。Through the coculture of AIRE transfected RAW264.7cell and spleen cell, we find AIRE can promote the generate of CD4+CD25+Treg cell and intensify its functional gene Foxp3 expression.It suggest that AIRE can influence the generation and function of CD4+CD25+Treg .2. The role of TLR4 in the influence of AIRE to CD4+CD25+Treg cellTo investigate The role of TLR4 in the influence of AIRE to CD4+CD25+Treg cell, we use the AIRE transfected RAW264.7cell,Through TLR4 pathway block,Thus to measure its influence to CD4+CD25+Treg count and function. Result reveals that after the TLR4 pathway block, the amount of Treg decreased and the functional gene Foxp3 expression down regulated. Which suggest AIRE maybe influence CD4+CD25+Treg cell through TLR4. Thus play an important role in the normal immune defence and sustain the peripheral immune toletance.3.The mechanism of the influence of AIRE to CD4+CD25+Treg cell by TLR4.To investigate the influence of AIRE to CD4+CD25+Treg cell through TLR4 regulate Notch1, we study the role of Notch1 in the influence of AIRE to CD4+CD25+Treg cell, we use the AIRE transfected RAW264.7cell,Through Notch1 pathway block,Thus to measure its influence to CD4+CD25+Treg count and function. Result reveals that after the Notch1 pathway block, the amount of Treg decreased and the functional gene Foxp3 expression down regulated. Which suggest AIRE maybe influence CD4+CD25+Treg cell through Notch1. Thus play an important role in the normal immune defence and sustain the peripheral immune toletance. But the experiment plan was not finished because of the limited time, we will do it in the next time.Summing up the above,we got these conclusion: AIRE maybe influence CD4+CD25+Treg cell through TLR4 and /or Notch1,thus play an important role in the normal immune defence and sustain the peripheral immune toletance.This study provide theory evidence for the full comprehension of role AIRE in the periphery immune tolerance.furthmore. At the same time use the influence of AIRE to APC function.through TLR4 to the function of Treg,Notch1 to the function of Treg,we could induce immue tolerance effectively(prophylaxis of autoimmune disease,anti-infection,anti-transplantaion and so on) or tolerance breakdown (anti-tumor). Thus find a holy new way to cure the disease。...