IADR Abstract Archives
DAMP Recognition In Oral Chronic Graft Versus Host Disease
Objectives: Salivary glands and oral mucosa (OM) are primary sites of chronic graft-versus-host disease (cGVHD). Early inflammatory events are believed to be critical for initiation of the graft-versus-host reaction following allogeneic hematopoietic stem cell transplant, and in shaping the disease character in subsequent cGVHD. The present study was designed to identify early signaling events leading to graft-versus-host recognition in oral tissues.
Methods: A well-characterized murine model of cGVHD, which reflects clinical and pathological symptoms of human oral cGVHD, was used in this study. BALB/c recipient mice were subjected to split-dose irradiation and transplanted with splenocytes and bone marrow cells from B10.D2 mice (allo group) or BALC/c mice (syn group). Mice were followed through day 42 post-transplant. Histology and flow cytometry confirmed cGVHD involvement in OM and submandibular gland (SMG). DAMP signaling was evaluated by PCR and western blot.
Results: Histologic examination of allo OM and SMG tissues showed damage and inflammation, whereas no significant changes were observed in the syn group. Cellular infiltration in the allo group was predominantly T cell driven in OM and SMG tissues. CD103+ DCs (DC1), known to produce type I interferon and cross-present antigens to activate CD8+T cells, were significantly elevated at days 14, 21, 28 and 42 post-transplant. Increased mRNA expression of DAMP-recognition molecules, cGAS, STING and IRF7, along with STING protein expression, was measured beginning at day 14 post-transplant in allo SMG. However, no significant differences in inflammasome signaling molecules, NLRP3, caspase-1 or IL-1b, were observed in this murine model.
Conclusions: These studies are ongoing but suggest that oral cGVHD may be triggered by DC1 bearing DAMP-receptors that activate cytotoxic CD8+ T cells that induce sustained damage. These data support future efforts to define the role of DAMPS at barrier sites in cGVHD.
Methods: A well-characterized murine model of cGVHD, which reflects clinical and pathological symptoms of human oral cGVHD, was used in this study. BALB/c recipient mice were subjected to split-dose irradiation and transplanted with splenocytes and bone marrow cells from B10.D2 mice (allo group) or BALC/c mice (syn group). Mice were followed through day 42 post-transplant. Histology and flow cytometry confirmed cGVHD involvement in OM and submandibular gland (SMG). DAMP signaling was evaluated by PCR and western blot.
Results: Histologic examination of allo OM and SMG tissues showed damage and inflammation, whereas no significant changes were observed in the syn group. Cellular infiltration in the allo group was predominantly T cell driven in OM and SMG tissues. CD103+ DCs (DC1), known to produce type I interferon and cross-present antigens to activate CD8+T cells, were significantly elevated at days 14, 21, 28 and 42 post-transplant. Increased mRNA expression of DAMP-recognition molecules, cGAS, STING and IRF7, along with STING protein expression, was measured beginning at day 14 post-transplant in allo SMG. However, no significant differences in inflammasome signaling molecules, NLRP3, caspase-1 or IL-1b, were observed in this murine model.
Conclusions: These studies are ongoing but suggest that oral cGVHD may be triggered by DC1 bearing DAMP-receptors that activate cytotoxic CD8+ T cells that induce sustained damage. These data support future efforts to define the role of DAMPS at barrier sites in cGVHD.