TY - JOUR
T1 - Cepharanthine blocks TSH receptor peptide presentation by HLA-DR3
T2 - Therapeutic implications to Graves’ disease
AU - Li, Cheuk Wun
AU - Osman, Roman
AU - Menconi, Francesca
AU - Concepcion, Erlinda
AU - Tomer, Yaron
PY - 2020/3
Y1 - 2020/3
N2 - We have previously identified a signature HLA-DR3 pocket variant, designated HLA-DRβ1-Arg74 that confers a high risk for Graves' Disease (GD). In view of the key role of HLA-DRβ1-Arg74 in triggering GD we hypothesized that thyroid-stimulating hormone receptor (TSHR) peptides that bind to the HLA-DRβ1-Arg74 pocket with high affinity represent key pathogenic TSHR peptides triggering GD, and that blocking their presentation to CD4+ T-cells can be used as a novel therapeutic approach in GD. There were several previous attempts to identify the major pathogenic TSHR peptide utilizing different methodologies, however the results were inconsistent and inconclusive. Therefore, the aim of our study was to use TSHR peptide binding affinity to HLA-DRβ1-Arg74 as a method to identify the key pathogenic TSHR peptides that trigger GD. Using virtual screening and ELISA and cellular binding assays we identified 2 TSHR peptides that bound with high affinity to HLA-DRβ1-Arg74 - TSHR.132 and TSHR.197. Peptide immunization studies in humanized DR3 mice showed that only TSHR.132, but not TSHR.197, induced autoreactive T-cell proliferation and cytokine responses. Next, we induced experimental autoimmune Graves’ disease (EAGD) in a novel BALB/c-DR3 humanized mouse model we created and confirmed TSHR.132 as a major DRβ1-Arg74 binding peptide triggering GD in our mouse model. Furthermore, we demonstrated that Cepharanthine, a compound we have previously identified as DRβ1-Arg74 blocker, could block the presentation and T-cell responses to TSHR.132 in the EAGD model.
AB - We have previously identified a signature HLA-DR3 pocket variant, designated HLA-DRβ1-Arg74 that confers a high risk for Graves' Disease (GD). In view of the key role of HLA-DRβ1-Arg74 in triggering GD we hypothesized that thyroid-stimulating hormone receptor (TSHR) peptides that bind to the HLA-DRβ1-Arg74 pocket with high affinity represent key pathogenic TSHR peptides triggering GD, and that blocking their presentation to CD4+ T-cells can be used as a novel therapeutic approach in GD. There were several previous attempts to identify the major pathogenic TSHR peptide utilizing different methodologies, however the results were inconsistent and inconclusive. Therefore, the aim of our study was to use TSHR peptide binding affinity to HLA-DRβ1-Arg74 as a method to identify the key pathogenic TSHR peptides that trigger GD. Using virtual screening and ELISA and cellular binding assays we identified 2 TSHR peptides that bound with high affinity to HLA-DRβ1-Arg74 - TSHR.132 and TSHR.197. Peptide immunization studies in humanized DR3 mice showed that only TSHR.132, but not TSHR.197, induced autoreactive T-cell proliferation and cytokine responses. Next, we induced experimental autoimmune Graves’ disease (EAGD) in a novel BALB/c-DR3 humanized mouse model we created and confirmed TSHR.132 as a major DRβ1-Arg74 binding peptide triggering GD in our mouse model. Furthermore, we demonstrated that Cepharanthine, a compound we have previously identified as DRβ1-Arg74 blocker, could block the presentation and T-cell responses to TSHR.132 in the EAGD model.
KW - Autoimmunity
KW - Graves' disease
KW - T-cells
KW - TSH receptor
KW - Thyroid
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U2 - 10.1016/j.jaut.2020.102402
DO - 10.1016/j.jaut.2020.102402
M3 - Article
C2 - 31980336
AN - SCOPUS:85078143908
VL - 108
JO - Journal of Autoimmunity
JF - Journal of Autoimmunity
SN - 0896-8411
M1 - 102402
ER -