TLR激動(dòng)劑imiquimod的研究進(jìn)展PPT課件

1、Introduction Imiquimod was the first small molecule approved for topical use in humans that was shown to act through the Toll-like receptor (TLR) pathway. Imiquimod activates innate immune cells that express TLR7 including plasmacytoid dendritic cells (pDC), B cells and likely some monocytes. Depend

2、ing on the cell type, this activation results in secretion of cytokines including interferon- (IFN-) and others, upregulation of costimulatory molecule expression and maturation and/or proliferation. 第1頁/共23頁 It was first identified as a compound that has anti-viral activity in pigs infected with he

3、rpes simplex virus, and has been successfully used for the treatment of genital warts caused by human papilloma virus in the clinical. Recent study revealed it also has direct proapoptotic activity against various tumor cell populations in vitro and in vivo.第2頁/共23頁the antiviral activity of imiquimo

4、d Imiquimod and its analogues have no direct in vitro antiviral activity and are not virucidal, rather the antiviral is indirect through cytokine induction and immune activation.第3頁/共23頁 resiquimod (S-28463), imiquimod (S-26308). Human peripheral blood mononuclear cells (PBMC)第4頁/共23頁Mo-DC, dendriti

5、c cells (DC) derived from monocytes, plasmacytoid dendritic cells (pDC)第5頁/共23頁Imiquimods proapoptotic effect in vitro Imiquimod inhibits cell proliferation in prostate cancer cell lines.（detected by MTT）第6頁/共23頁Imiquimod induces apoptosis by imiquimod dose-dependent and by pass of mitochondria-depe

6、ndent in prostate cancer cells第7頁/共23頁A TLR7 inhibitor chloroquine does not restore the growth inhibition by imiquimod Results: Imiquimod induced apoptosis was independently of TLR7 and MyD88第8頁/共23頁Imiquimod inhibits in vivo growth of prostate cancer in mice第9頁/共23頁the role of imiquimod in macropha

7、ge Numerous macrophages are present in the shoulder regions of rupture-prone life threatening atherosclerotic plaques. Removal of macrophages from plaques by macrophage-specific induction of cell death could represent an attractive approach to stabilize the structure of the plaque. To initiate selec

8、tive macrophage death, we examined Toll-like receptor 7 (TLR7) as a potential target, since it is expressed in macrophages but not in SMCs.第10頁/共23頁TLR7 expressed in macrophages but not in SMCsmacrophages (M), bone marrow-derived macrophages (BMM) from WT,TLR7+ and TLR7- mice, and mouse aortic SMCs

9、from WT mice.第11頁/共23頁imiquimod induced cell apoptosis is dependent on TLR7b, e Macrophages and SMCs were incubated for 24 h with imiquimod (0.130 lg/ml). Cell viability was examined by neutralred assays.第12頁/共23頁imiquimod induced macrophage autophagy by TLR7第13頁/共23頁Imiquimod-induced macrophage inf

10、lammation is TLR7 dependent第14頁/共23頁the role of imiquimod in atherosclerotic plaque Local administration of imiquimod to rabbit atheroma-like lesions induced autophagy in macrophages without affecting SMCs, as demonstrated by TEM, and induced an increase in plaque area. In vivo treatment of atheroma

11、-like lesions with imiquimod did not deplete macrophages, but rather stimulated macrophage infiltration due to cytokine release.第15頁/共23頁a Transmission electron-microscopic images of macrophages showautophagosome formation after imiquimod treatment for 7days. b Images of SMCs shown autophagosome for

12、mation after imiquimod treatment第16頁/共23頁I, intima; M, media; a, VCAM-1; b, T cells; c, macrophages第17頁/共23頁 These in vivo results seem to be in contrast with our invitro findings (imiquimod induced autophagic death). The contradictory effects of imiquimod in vivo versus in vitro might be misleading

13、 because the level of autophagy induced by both conditions could be entirely different.第18頁/共23頁TLR7/8 agonists as vaccine adjuvants Imiquimod and similar analogs have vaccine adjuvant activity came from studies demonstrating the ability of these molecules to activate APCs, induce immune modulatory cytokines and activate B- and T-cell responses. 第19頁/共23頁 Mice vaccinated intradermally with microneedles coated with imiquimod and H1N1 HA induced IFN-producing T-cell response, high levels of IgG2 and protective immunity following a lethal challenge with a mouse-adapted infuenza strai