Lombardi A, Concepcion E, Hou H, Arib H, Mezei M, Osman R, Tomer Y. Retro-inverso D-peptides as a novel targeted immunotherapy for Type 1 diabetes.
J Autoimmun 2020;
115:102543. [PMID:
32951964 DOI:
10.1016/j.jaut.2020.102543]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/29/2020] [Accepted: 08/30/2020] [Indexed: 02/07/2023]
Abstract
Over the past four decades, the number of people with Type 1 Diabetes (T1D) has increased by 4% per year, making it an important public health challenge. Currently, no curative therapy exists for T1D and the only available treatment is insulin replacement. HLA-DQ8 has been shown to present antigenic islet peptides driving the activation of CD4+ T-cells in T1D patients. Specifically, the insulin peptide InsB:9-23 activates self-reactive CD4+ T-cells, causing pancreatic beta cell destruction. The aim of the current study was to identify retro-inverso-d-amino acid based peptides (RI-D-peptides) that can suppress T-cell activation by blocking the presentation of InsB:9-23 peptide within HLA-DQ8 pocket. We identified a RI-D-peptide (RI-EXT) that inhibited InsB:9-23 binding to recombinant HLA-DQ8 molecule, as well as its binding to DQ8 expressed on human B-cells. RI-EXT prevented T-cell activation in a cellular antigen presentation assay containing human DQ8 cells loaded with InsB:9-23 peptide and murine T-cells expressing a human T-cell receptor specific for the InsB:9-23-DQ8 complex. Moreover, RI-EXT blocked T-cell activation by InsB:9-23 in a humanized DQ8 mice both ex vivo and in vivo, as shown by decreased production of IL-2 and IFN-γ and reduced lymphocyte proliferation. Interestingly, RI-EXT also blocked lymphocyte activation and proliferation by InsB:9-23 in PBMCs isolated from recent onset DQ8-T1D patients. In summary, we discovered a RI-D-peptide that blocks InsB:9-23 binding to HLA-DQ8 and its presentation to T-cells in T1D. These findings set the stage for using our approach as a novel therapy for patients with T1D and potentially other autoimmune diseases.
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