Prevention and induction of autoimmune exocrinopathy is dependent on pathogenic autoantigen cleavage in murine Sjogren's syndrome

K Saegusa, N Ishimaru, K Yanagi… - The Journal of …, 2002 - journals.aai.org
K Saegusa, N Ishimaru, K Yanagi, K Mishima, R Arakaki, T Suda, I Saito, Y Hayashi
The Journal of Immunology, 2002journals.aai.org
The in vivo role of autoantigen cleavage during apoptosis in autoimmune diseases remains
unclear. Previously, we found a cleavage product of 120-kDa α-fodrin as an important
autoantigen in the pathogenesis of primary Sjögren's syndrome (SS). In the murine primary
SS model, tissue-infiltrating CD4+ T cells purified from the salivary glands bear a large
proportion of Fas ligand, and the salivary gland duct cells constitutively possess Fas.
Infiltrating CD4+ T cells, but not CD8+ T cells, identified significant 51 Cr release against …
Abstract
The in vivo role of autoantigen cleavage during apoptosis in autoimmune diseases remains unclear. Previously, we found a cleavage product of 120-kDa α-fodrin as an important autoantigen in the pathogenesis of primary Sjögren’s syndrome (SS). In the murine primary SS model, tissue-infiltrating CD4+ T cells purified from the salivary glands bear a large proportion of Fas ligand, and the salivary gland duct cells constitutively possess Fas. Infiltrating CD4+ T cells, but not CD8+ T cells, identified significant 51 Cr release against mouse salivary gland cells. In vitro studies demonstrated that apoptotic mouse salivary gland cells result in a specific α-fodrin cleavage into 120 kDa and that preincubation with caspase inhibitor peptides blocked α-fodrin cleavage. In vivo treatment with caspase inhibitors N-benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone and N-acetyl-Asp-Glu-Val-Asp-al-CHO into the murine model results in dramatic inhibitory effects on the development of autoimmune lesions and in restoration of sicca syndrome. Furthermore, we found that immunization with recombinant α-fodrin protein identical with an autoantigen into normal recipients induced autoimmune lesions similar to SS. These data indicate that prevention and induction of autoimmune exocrinopathy is dependent on autoantigen cleavage via caspase cascade and that caspase inhibitors might provide a new therapeutic option directed at reducing tissue damage in the murine model for SS.
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