Résumé
Objective:To investigate whether FcγRⅡb rs775 single nucleotide polymorphism confers susceptibility to Hashimoto′s thyroiditis and its impact on expression of FcγRⅡb protein on B cell surface.Methods:A total of 187 Hashimoto′s thyroiditis patients(HT group) were enrolled, including 46 males(24.60%) and 141 females(75.40%), with a median age of 43(32, 53) years, and 187 healthy controls(conrol group), including 62 males(33.16%) and 125 females(66.84%), with a median age of 41(31, 51) years. The peripheral blood of two groups were sequenced, genotype and allele frequencies distribution of FcγRⅡb rs775 T>C were compared with clinical parameters as strata between the two groups. At the same time, the expression of inhibitory receptor FcγRⅡb on B cell surface was detected using flow cytometry.Results:Compared with control group, the mutant homozygous CC genotype was obviously enrichment in HT group( OR=3.321, 95% CI 1.175-9.386, P=0.018), and the proportion of CC genotype increased in male of HT group( P=0.076). However, there is no significant difference in genotype and allele frequencies between control group and HT group after stratification by sex. In addition, the percentage of FcγRⅡb on B cell surface decreased significantly in HT group( P=0.029). Conclusion:There was no significant correlation between FcγRⅡb polymorphism and the down-regulation of FcγRⅡb protein on B cell surface in Hashimoto′s thyroiditis patients, and FcγRⅡb can be a predisposed factor for Hashimoto′s thyroiditis.
Résumé
Objective To investigate the effect of knockout of IgG receptor( FcγRIIB) on systemic and adipose tis-sue inflammation and fat tissue lipid metabolism treated with high-fat diet ( HFD) . Methods We used 10 male mice with IgG receptor FcγRIIB knockout ( FcγRIIB-/-) and another 10 male FcγRIIB+/+mice as control, and trea-ted them with HFD. At the end of the 17th week, mice were weighed, the blood was taken by cardiac puncture af-ter sacrifice. Adipose tissue was collected to measure inflammation and lipid metabolism. Results Compared with FcγRIIB+/+mice, FcγRIIB-/-mice had significantly increased levels of inflammatory cytokines, IL-6, TNF-α, and IFN-γ in the serum, and increased macrophage infiltration in adipose tissue. M1 polarization gene MCP-1 and TNF-α increased ( P＜0.05) and M2 polarization gene ARG and IL-10 did not differ significantly. However, there was no significant difference in body mass, adipocyte size and expression of lipid metabolism related genes PPARG, CEBPα, FASn, HSL, ATGL, UCP-1 and GLUT4. Conclusions Under HFD treatment, knocking out the IgG re-ceptor FcγRIIB aggravates the inflammatory response of the whole body and adipose tissue, but cannot influence lipid metabolism of adipose tissue and body weight.
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Objective To clone and express the extracellular portion of mouse Fcγreceptor Ⅱ-b ( FcγRⅡb) and to analyze the functions of the expressed proteins in a mouse model of systemic lupus ery-thematosus ( SLE) .Methods The gene fragment encoding FcγRⅡb was amplified by PCR, and then in-serted into the prokaryotic expression vector pET-32a(+) to construct the recombinant expression plasmid pET-FcγRⅡb.The expression plasmid was identified with restriction enzymes and then sent to the Shanghai Bio-Engineering Co.LTD for further sequencing analysis.The transformed Escherichia coli ( E.coli) BL21 ( DE3) strains carrying the recombinant expression plasmid pET-FcγRⅡb were induced by isopropylβ-D-1-thiogalactoside ( IPTG) .The expressed fusion proteins were analyzed by Western blot assay and purified with purification kits.The immune complex ( IC)-binding ability of FcγRⅡb was measured by ELISA.MRL/lpr mice with SLE in both the prevention (12 weeks old, n=40) and the treatment groups (19 weeks old, n=40) were randomly divided into four groups including 60 μl (4.8 μg) treatment group, 120 μl (9.6 μg) treatment group, 180μl (14.4μg) treatment group and PBS treatment group with 10 mouse in each group. The MRL/lpr mice with SLE were injected with the fusion protein through tail vein once a week for four con-secutive weeks.Serum samples were collected from each mouse after one week of observation.The levels of FcγRⅡb in soluble form in mice form both the prevention and treatment groups as well as the levels of anti-double stranded DNA antibodies were detected by ELISA.Results The gene encoding FcγRⅡb was ampli-fied and the recombinant expression plasmid pET-FcγRⅡb was successfully constructed.The recombinant proteins were expressed in the prokaryotic expression system, and then successfully purified.The recombi-nant proteins could bind to IC.Compared with the corresponding PBS control group, the levels of FcγRⅡb in soluble form were increased in mice from both prevention and treatment groups after treating with various concentrations of the recombinant protein (P<0.05).Significant differences in the levels of FcγRⅡb were found among mice of the same age after treating with different concentrations of the recombinant protein ( P<0.05).Compared with the corresponding PBS control group, the levels of anti-double stranded DNA anti-bodies were decreased in mice from both prevention and treatment groups after treating with various concen-trations of the recombinant protein (P<0.05).The levels of anti-double stranded DNA antibodies were grad-ually decreased along with the increasing dosage of protein (P<0.05).Conclusion The extracellular por-tion of murine FcγRⅡb in soluble form was successfully expressed.The recombinant proteins played a cer-tain role in the prevention and treatment of SLE in a mouse model.
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ObjectiveTo investigate the alteration of Fc gamma receptors expressed on monocytes in childhood acute immune thrombocytopenia (aITP).Methods27 patients with aITP and 25 health controls were enrolled in this study.The expression of FcγR Ⅰ and FcγRⅢ on monocytes surface was determined by flow cytometry.Real-time PCR was performed to detect the levels of FcγR Ⅱ a and FcγR.Ⅱ b mRNA.The plasma concentration of IL-4 and IFN-γwas analyzed by ELISA.ResultsThe expression of FcγR I and FcγRⅢ on monocytes was significantly highet in ITP pationts than thatinhealth control group.Transcription levels of FcγR Ⅱ a mRNA and the ratio of FcγR Ⅱ a/Ⅱ b mRNA on monocytes were significantly elevated,while the inhibitory FcγR Ⅱ b mRNA was significant lower in aITP patients (P＜0.05) ; in comparison with healthy controls. After dexamethasone treatment,the stimulatory FcγR Ⅰ,FcγRⅢ and FcγR Ⅱ a mRNA were significantly decreased while inhibitory FcγR Ⅱ b mRNA was increased.(2)The higher levels of plasma IFN-y and lower IL-4 were to be found in aITP patients compared with healthy controls.Correlation analysis showed that the level of plasma IFN-γwas positively correlated with the elevated expression of FcγR Ⅱ a mRNA on monocytes,while the level of IL-4 was positively correlated with FcγRⅡ b mRNA.Conclusion The over expression of inhibitory FcγRs and the down-regulation of inhibitory FcγR Ⅱb mRNA on monocytes,and the imbalance of stimulatory and inhibitory FcγR might be involve in immunological pathogenesis of the acute ITP.The alteration levels of plasma pro-inflammatory cytokine IFN-γand anti-inflammatory cytokine IL-4 might be involved in imbalance expression of FcγR in acute ITP.Dexamethasone therapy could shift the balance between stimulatory and inhibitory FcγR toward inhibitory FcγR Ⅱ b in aITP patients.