Chenxu Zhao, Zhiming Sun, Shuaihang Wang, Jixin Zhang, Jumei Liu, Lei Chen, Guizhi Lu, Yang Yu, Ying Gao
{"title":"IgG4 glycosylation contributes to the pathogenesis of IgG4 Hashimoto's thyroiditis via the complement pathway.","authors":"Chenxu Zhao, Zhiming Sun, Shuaihang Wang, Jixin Zhang, Jumei Liu, Lei Chen, Guizhi Lu, Yang Yu, Ying Gao","doi":"10.1530/ETJ-24-0156","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>To explore whether IgG4 is involved in the pathogenesis of IgG4 HT.</p><p><strong>Methods: </strong>Serum TgAb IgG4 and TPOAb IgG4 were measured in IgG4 HT and non-IgG4 HT. C1q, mannose-binding lectin (MBL), Bb, C3d, C4d, and membrane attack complex (MAC) in thyroid tissues from IgG4 HT, non-IgG4 HT, and controls were examined by immunohistochemistry. We assessed IgG4 and MAC deposition in mouse thyroid by immunohistochemistry after injecting purified IgG4 into mice. The glycosylation patterns of TgAb IgG4 from IgG4 HT were identified by MALDI-TOF-MS. The ability of IgG4 to bind to MBL before and after deglycosylation was assessed by ELISA. MBL and MAC fluorescence were detected in thyrocytes after the addition of IgG4 or deglycosylated IgG4.</p><p><strong>Results: </strong>Serum TgAb IgG4 and TPOAb IgG4 levels were significantly higher in the IgG4 HT group. MBL, Bb, C3d, C4d, and MAC levels were significantly higher in the thyroid tissues of IgG4 HT than in non-IgG4 HT (all P < 0.001). IgG4 colocalized with MBL by immunofluorescence. In mice, follicular cell structure disruption was observed after the injection of IgG4 from IgG4 HT, as well as the colocalization of IgG4 with MAC. High levels of TgAb IgG4 glycosylation patterns, including monogalactose glycan (G1F), galactose-deficient glycan (G0F), and high-mannose glycan (M5), were detected in IgG4 HT. After deglycosylation, IgG4 reduced its ability to bind to MBL, and there was low MBL and MAC activation in thyrocytes.</p><p><strong>Conclusion: </strong>High levels of IgG4 glycosylation patterns, including G1F, G0F, and M5, may activate the complement lectin pathway, thereby participating in the pathogenesis of IgG4 HT.</p>","PeriodicalId":12159,"journal":{"name":"European Thyroid Journal","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Thyroid Journal","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1530/ETJ-24-0156","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/10/1 0:00:00","PubModel":"Print","JCR":"Q2","JCRName":"ENDOCRINOLOGY & METABOLISM","Score":null,"Total":0}
引用次数: 0
Abstract
Background: To explore whether IgG4 is involved in the pathogenesis of IgG4 HT.
Methods: Serum TgAb IgG4 and TPOAb IgG4 were measured in IgG4 HT and non-IgG4 HT. C1q, mannose-binding lectin (MBL), Bb, C3d, C4d, and membrane attack complex (MAC) in thyroid tissues from IgG4 HT, non-IgG4 HT, and controls were examined by immunohistochemistry. We assessed IgG4 and MAC deposition in mouse thyroid by immunohistochemistry after injecting purified IgG4 into mice. The glycosylation patterns of TgAb IgG4 from IgG4 HT were identified by MALDI-TOF-MS. The ability of IgG4 to bind to MBL before and after deglycosylation was assessed by ELISA. MBL and MAC fluorescence were detected in thyrocytes after the addition of IgG4 or deglycosylated IgG4.
Results: Serum TgAb IgG4 and TPOAb IgG4 levels were significantly higher in the IgG4 HT group. MBL, Bb, C3d, C4d, and MAC levels were significantly higher in the thyroid tissues of IgG4 HT than in non-IgG4 HT (all P < 0.001). IgG4 colocalized with MBL by immunofluorescence. In mice, follicular cell structure disruption was observed after the injection of IgG4 from IgG4 HT, as well as the colocalization of IgG4 with MAC. High levels of TgAb IgG4 glycosylation patterns, including monogalactose glycan (G1F), galactose-deficient glycan (G0F), and high-mannose glycan (M5), were detected in IgG4 HT. After deglycosylation, IgG4 reduced its ability to bind to MBL, and there was low MBL and MAC activation in thyrocytes.
Conclusion: High levels of IgG4 glycosylation patterns, including G1F, G0F, and M5, may activate the complement lectin pathway, thereby participating in the pathogenesis of IgG4 HT.
期刊介绍:
The ''European Thyroid Journal'' publishes papers reporting original research in basic, translational and clinical thyroidology. Original contributions cover all aspects of the field, from molecular and cellular biology to immunology and biochemistry, from physiology to pathology, and from pediatric to adult thyroid diseases with a special focus on thyroid cancer. Readers also benefit from reviews by noted experts, which highlight especially active areas of current research. The journal will further publish formal guidelines in the field, produced and endorsed by the European Thyroid Association.