The mutated major histocompatibility complex (MHC) class I that contains donor-type epitopes displayed on recipient-type molecule was show- n to inhibit acute and chronic rejection and in-duce indefinite survival of h...The mutated major histocompatibility complex (MHC) class I that contains donor-type epitopes displayed on recipient-type molecule was show- n to inhibit acute and chronic rejection and in-duce indefinite survival of heterotopic cardiac allografts when administered in combination with a sub-therapeutic dose of cyclosporine (CsA) in a rat transplantation model. To eluci-date the molecular pathways involved in the immunosuppressive effects of the mutated MHC molecule, we analyzedgene and protein expres-sion profile during early and late phase follow-ing post-transplantation. Cytoskeletal structure analysis and expression status of Rho GTPase proteins, vacuolar transport and cytoskeleton regulatory pathways involved in immune re-sponse in T and dendritic cells demonstrated the novel mechanism for the abrogation of chronic rejection. Our studies confirm a new role of Rho GTPase pathway in the modification of T cell motility and infiltration of the graft. We discuss these results within the framework of the most recent literature on MHC and molecu-lar machinery controlling T cell functions and dendritic cell antigen presentation.展开更多
Background: We have shown previously that the abrogation of acute and chronic rejection of rat cardiac allografts occurs through the down-regulation of RhoA pathway and involves the changes in RhoA kinase (ROCK)-depen...Background: We have shown previously that the abrogation of acute and chronic rejection of rat cardiac allografts occurs through the down-regulation of RhoA pathway and involves the changes in RhoA kinase (ROCK)-dependent actin cytoskeleton and T cell motility. Here we studied the ability of the Y-27632, a highly selective inhibitor of Rho-associated protein kinase p160ROCK (ROCK1), to abrogate chronic rejection of the allograft and influence T cell infiltration. Methods: Heterotopic cardiac transplants were performed between donor Wistar Furth (WF) and ACI recipient rats. Controls received sub-therapeutic dose of cyclosporine (CsA, 10 mg/kg) for 3 days or 7 days therapeutic dose of cyclosporine. The experimental groups of ACI recipient received one preoperative dose of the Y-27632 inhibitor (2 mg/kg, gavage feed) in conjunction with the sub-therapeutic dose of CsA for 3 days or inhibitor alone for 7 days. The cardiac grafts were harvested at 100 days of post-transplantation for histological and immunohistochemical assessment of chronic rejection, vascular sclerosis, and infiltration by different T cell subtypes. Results: Cardiac allografts from recipients exposed to Y-27632 inhibitor in conjunction with sub-therapeutic dose of CsA showed drastically reduced vascular sclerosis, minimal myocardial total cellular infiltration, and were selectively infiltrated with Foxp3+ T regulatory (Treg) cells. Conclusions: Our novel finding that a single dose of the ROCK1 inhibitor Y-27632 attenuates chronic rejection in rat cardiac model system by promoting development of Treg cells warrants its potential as a novel therapeutic agent specific for the inhibition of chronic rejection.展开更多
文摘The mutated major histocompatibility complex (MHC) class I that contains donor-type epitopes displayed on recipient-type molecule was show- n to inhibit acute and chronic rejection and in-duce indefinite survival of heterotopic cardiac allografts when administered in combination with a sub-therapeutic dose of cyclosporine (CsA) in a rat transplantation model. To eluci-date the molecular pathways involved in the immunosuppressive effects of the mutated MHC molecule, we analyzedgene and protein expres-sion profile during early and late phase follow-ing post-transplantation. Cytoskeletal structure analysis and expression status of Rho GTPase proteins, vacuolar transport and cytoskeleton regulatory pathways involved in immune re-sponse in T and dendritic cells demonstrated the novel mechanism for the abrogation of chronic rejection. Our studies confirm a new role of Rho GTPase pathway in the modification of T cell motility and infiltration of the graft. We discuss these results within the framework of the most recent literature on MHC and molecu-lar machinery controlling T cell functions and dendritic cell antigen presentation.
文摘Background: We have shown previously that the abrogation of acute and chronic rejection of rat cardiac allografts occurs through the down-regulation of RhoA pathway and involves the changes in RhoA kinase (ROCK)-dependent actin cytoskeleton and T cell motility. Here we studied the ability of the Y-27632, a highly selective inhibitor of Rho-associated protein kinase p160ROCK (ROCK1), to abrogate chronic rejection of the allograft and influence T cell infiltration. Methods: Heterotopic cardiac transplants were performed between donor Wistar Furth (WF) and ACI recipient rats. Controls received sub-therapeutic dose of cyclosporine (CsA, 10 mg/kg) for 3 days or 7 days therapeutic dose of cyclosporine. The experimental groups of ACI recipient received one preoperative dose of the Y-27632 inhibitor (2 mg/kg, gavage feed) in conjunction with the sub-therapeutic dose of CsA for 3 days or inhibitor alone for 7 days. The cardiac grafts were harvested at 100 days of post-transplantation for histological and immunohistochemical assessment of chronic rejection, vascular sclerosis, and infiltration by different T cell subtypes. Results: Cardiac allografts from recipients exposed to Y-27632 inhibitor in conjunction with sub-therapeutic dose of CsA showed drastically reduced vascular sclerosis, minimal myocardial total cellular infiltration, and were selectively infiltrated with Foxp3+ T regulatory (Treg) cells. Conclusions: Our novel finding that a single dose of the ROCK1 inhibitor Y-27632 attenuates chronic rejection in rat cardiac model system by promoting development of Treg cells warrants its potential as a novel therapeutic agent specific for the inhibition of chronic rejection.
