The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them ...The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them with a mechanism to escape the immune surveillance. In melanoma, HLA-G antigen expression has been found in 30% of surgically removed lesions but in less than 1% of established cell lines. One possible mechanism underlying the differential HLA-G expression in vivo and in vitro is that the HLA-G gene is epigenetically repressed in melanoma cells in vitro. To test this hypothesis, we treated the HLA-G negative melanoma cell line OCM-1A with the DNA methyltransferase inhibitor 5-aza-2＇-deoxycytidine （5-AC） and analyzed whether HLA-G expression can be restored. Our data strongly suggest that HLA-G is silenced as a result of CpG hypermethylation within a 5＇ regulatory region encompassing 220 bp upstream of the start codon. After treatment, HLA-G mRNA expression was dramatically increased. Western blot and flow cytometry showed that HLA-G protein was induced. Interestingly, HLA-G cell surface expression on the 5-AC treated OCM-1A cells is much less than that on the HLA-G positive JEG-3 cells while a similar amount of total HLA-G was observed. Possible mechanisms for the difference were analyzed in the study such as cell cold-treatment, peptide loading and antigen processing machinery components （APM） as well as β2 microglobulin （β2-m） expression. Data revealed that the APM component calreticulin might be involved in the lower HLA-G surface expression on OCM-1A cells. Taken together, our results indicated that DNA methylation is an important epigenetic mechanism by which HLA-G antigen expression is modulated in melanoma cells in vitro. Furthermore, to the first time, we hypothesized that the deficiency of calreticulin might be involved in the low HLA-G surface expression on the 5-AC treated OCM-1A cells.展开更多
Autoimmune mechanisms, including cellular and humoral immune, are likely to participate in the pathogenesis of at least a subgroup of idiopathic dilated cardiomyopathy （IDC）, in which cellular immune-mediation plays...Autoimmune mechanisms, including cellular and humoral immune, are likely to participate in the pathogenesis of at least a subgroup of idiopathic dilated cardiomyopathy （IDC）, in which cellular immune-mediation plays a more important role. Cytotoxic T lymphocyte associated antigen-4 （CTLA-4） is the major negative regulatory factor of cellular immunity. This study was conducted to investigate the association of CTIA-4 gene exon 1 A49→G polymorphism with susceptibility to IDC in Han Chinese and its influences on serum soluble CTIA-4 （sCrLA-4） and Th1/Th2 cytokine bias. Polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） techniques were used to analyze the dimorphism of CTL4-4 exon 1 in the unrelated Han ethnic population in Heilongjiang Province （ including 48 IDC patients and 50 normal controls）. Serum sCTLA-4, IFN-γ and IL-4 were evaluated by ELISA, with the ratio of IFN-γ/IL-4 as indicator for Th1/Th2 bias. Compared with controls, the frequencies of GG genotype （0.6042 and 0.3600, P = 0.012） and the G allele （0.7396 and 0.5600, P = 0.008） were significantly increased in IDC patients. Increased serum sCTIA-4 was found in the 1DC group compared with the controls [ （ 1.87 ± 1.06） μg/L vs. （0.54 ± 0.19） 〉g/L, P 〈 0.05 ~. 1FN-7 was much lower in IDC patients than that of the controls [ （ 16.38 ± 6.25） ng/L vs. （29.81 ± 10.66） ng/L （P 〈 0.05）~., whereas no statistical difference of IL-4 was found between the two groups I （12.85 ± 1.86） ng/L vs. （12.11 ± 2.76） ng/L], so the ratio of IFN-γ/IL-4 declined significantly （ 1.63 ± 0.50 vs. 3.01 ± 0.89, P 〈 0.05）. Linear regression analysis manifested a significant interrelationship between the GG genotype, G allele frequencies and serum sCTLA-4, IFN-γ/IL-4 in the IDC group （ r = 0.57, P = 0. 021 and r = 0.32, P = 0. 036）. CTLA-4 gene A49→G substitution was associated with an increased IDC risk, which implicated that the CTLA-4 gene exon 1 may have a considerable role in autoimmune cardiac damage, possibly via a Thr→Ala change in signal peptide, which influences the protein synthesis and modification processes, with a result of functional alteration of sCTLA-4. The bias of Th1/Th2 paradigm was associated with the increased sCTIA-4 under certain background of immunogenetics.展开更多
The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global ...The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global gene expression profiling of Beauveria bassiana at 36, 60, 84 and 108 h after topical infection of Anopheles stephensi adult mosquitoes using RNA sequencing （RNA-Seq）. A total of 5,354 differentially expressed genes （DEGs） are identified over the course of fungal infection. When the fungus grows on the mosquito cuticle, up-regulated DEGs include adhesion-related genes involved in cuticle attachment, Pthl l-like GPCRs hypothesized to be involved in host recognition, and extracellular enzymes involved in the degradation and penetration of the mosquito cuticle. Once in the mosquito hemocoel, the fungus evades mosquito immune system probably through up-regulating expression of 13-1,3-glucan degrading enzymes and chitin synthesis enzymes for remodeling of cell walls. Moreover, six previous unknown SSCP （small secreted cysteine-rich proteins） are significantly up-regulated, which may serve as ＂effectors＂ to suppress host defense responses. B. bassiana also induces large amounts of antioxidant genes to mitigate host-generated exogenous oxidative stress. At late stage of infection, B. bassiana activates a broad spectrum of genes including nutrient degrading enzymes, some transporters and metabolism pathway components, to exploit mosquito tissues and hemolymph as a nutrient source for hyphal growth. These findings establish an important framework of knowledge for further comprehensive elucidation of fungal pathogenesis and molecular mechanism of Beauveria-mosquito interactions.展开更多
文摘The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them with a mechanism to escape the immune surveillance. In melanoma, HLA-G antigen expression has been found in 30% of surgically removed lesions but in less than 1% of established cell lines. One possible mechanism underlying the differential HLA-G expression in vivo and in vitro is that the HLA-G gene is epigenetically repressed in melanoma cells in vitro. To test this hypothesis, we treated the HLA-G negative melanoma cell line OCM-1A with the DNA methyltransferase inhibitor 5-aza-2＇-deoxycytidine （5-AC） and analyzed whether HLA-G expression can be restored. Our data strongly suggest that HLA-G is silenced as a result of CpG hypermethylation within a 5＇ regulatory region encompassing 220 bp upstream of the start codon. After treatment, HLA-G mRNA expression was dramatically increased. Western blot and flow cytometry showed that HLA-G protein was induced. Interestingly, HLA-G cell surface expression on the 5-AC treated OCM-1A cells is much less than that on the HLA-G positive JEG-3 cells while a similar amount of total HLA-G was observed. Possible mechanisms for the difference were analyzed in the study such as cell cold-treatment, peptide loading and antigen processing machinery components （APM） as well as β2 microglobulin （β2-m） expression. Data revealed that the APM component calreticulin might be involved in the lower HLA-G surface expression on OCM-1A cells. Taken together, our results indicated that DNA methylation is an important epigenetic mechanism by which HLA-G antigen expression is modulated in melanoma cells in vitro. Furthermore, to the first time, we hypothesized that the deficiency of calreticulin might be involved in the low HLA-G surface expression on the 5-AC treated OCM-1A cells.
文摘Autoimmune mechanisms, including cellular and humoral immune, are likely to participate in the pathogenesis of at least a subgroup of idiopathic dilated cardiomyopathy （IDC）, in which cellular immune-mediation plays a more important role. Cytotoxic T lymphocyte associated antigen-4 （CTLA-4） is the major negative regulatory factor of cellular immunity. This study was conducted to investigate the association of CTIA-4 gene exon 1 A49→G polymorphism with susceptibility to IDC in Han Chinese and its influences on serum soluble CTIA-4 （sCrLA-4） and Th1/Th2 cytokine bias. Polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） techniques were used to analyze the dimorphism of CTL4-4 exon 1 in the unrelated Han ethnic population in Heilongjiang Province （ including 48 IDC patients and 50 normal controls）. Serum sCTLA-4, IFN-γ and IL-4 were evaluated by ELISA, with the ratio of IFN-γ/IL-4 as indicator for Th1/Th2 bias. Compared with controls, the frequencies of GG genotype （0.6042 and 0.3600, P = 0.012） and the G allele （0.7396 and 0.5600, P = 0.008） were significantly increased in IDC patients. Increased serum sCTIA-4 was found in the 1DC group compared with the controls [ （ 1.87 ± 1.06） μg/L vs. （0.54 ± 0.19） 〉g/L, P 〈 0.05 ~. 1FN-7 was much lower in IDC patients than that of the controls [ （ 16.38 ± 6.25） ng/L vs. （29.81 ± 10.66） ng/L （P 〈 0.05）~., whereas no statistical difference of IL-4 was found between the two groups I （12.85 ± 1.86） ng/L vs. （12.11 ± 2.76） ng/L], so the ratio of IFN-γ/IL-4 declined significantly （ 1.63 ± 0.50 vs. 3.01 ± 0.89, P 〈 0.05）. Linear regression analysis manifested a significant interrelationship between the GG genotype, G allele frequencies and serum sCTLA-4, IFN-γ/IL-4 in the IDC group （ r = 0.57, P = 0. 021 and r = 0.32, P = 0. 036）. CTLA-4 gene A49→G substitution was associated with an increased IDC risk, which implicated that the CTLA-4 gene exon 1 may have a considerable role in autoimmune cardiac damage, possibly via a Thr→Ala change in signal peptide, which influences the protein synthesis and modification processes, with a result of functional alteration of sCTLA-4. The bias of Th1/Th2 paradigm was associated with the increased sCTIA-4 under certain background of immunogenetics.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB11010500)National Key R&D Program of China(2017YFD0200400,SQ2017ZY060066)the Hundred Talents Program of the Chinese Academy of Sciences
文摘The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global gene expression profiling of Beauveria bassiana at 36, 60, 84 and 108 h after topical infection of Anopheles stephensi adult mosquitoes using RNA sequencing （RNA-Seq）. A total of 5,354 differentially expressed genes （DEGs） are identified over the course of fungal infection. When the fungus grows on the mosquito cuticle, up-regulated DEGs include adhesion-related genes involved in cuticle attachment, Pthl l-like GPCRs hypothesized to be involved in host recognition, and extracellular enzymes involved in the degradation and penetration of the mosquito cuticle. Once in the mosquito hemocoel, the fungus evades mosquito immune system probably through up-regulating expression of 13-1,3-glucan degrading enzymes and chitin synthesis enzymes for remodeling of cell walls. Moreover, six previous unknown SSCP （small secreted cysteine-rich proteins） are significantly up-regulated, which may serve as ＂effectors＂ to suppress host defense responses. B. bassiana also induces large amounts of antioxidant genes to mitigate host-generated exogenous oxidative stress. At late stage of infection, B. bassiana activates a broad spectrum of genes including nutrient degrading enzymes, some transporters and metabolism pathway components, to exploit mosquito tissues and hemolymph as a nutrient source for hyphal growth. These findings establish an important framework of knowledge for further comprehensive elucidation of fungal pathogenesis and molecular mechanism of Beauveria-mosquito interactions.
