Permanent acceptance of mouse cardiac allografts with CD40 siRNA to induce regulatory myeloid cells by use of a novel polysaccharide siRNA delivery system

• Published in: Gene therapy Vol. 22; no. 3; pp. 217 - 226
• Main Authors: Zhang, Q, Ichimaru, N, Higuchi, S, Cai, S, Hou, J, Fujino, M, Nonomura, N, Kobayashi, M, Ando, H, Uno, A, Sakurai, K, Mochizuki, S, Adachi, Y, Ohno, N, Zou, H, Xu, J, Li, X-K, Takahara, S
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2015; Nature Publishing Group
• Subjects: 42/89; 64; 64/60; 692/699/75; Adjuvants, Immunologic - chemistry; Adjuvants, Immunologic - metabolism; Adoptive transfer; Allografts; Allografts - cytology; Allografts - physiology; Animals; Antigens; Beta glucan; Biomedical and Life Sciences; Biomedicine; CD4 antigen; CD4-Positive T-Lymphocytes - immunology; CD40 antigen; CD40 Antigens - metabolism; CD40L protein; CD8 antigen; CD8-Positive T-Lymphocytes - immunology; Cell Biology; Cells; Cells, Cultured; Dendritic cells; Dendritic Cells - immunology; Disease Models, Animal; Foxp3 protein; Gene Expression; Gene silencing; Gene Therapy; Genes; Health aspects; Heart; Heart Transplantation; Homografts; Human Genetics; Immunological tolerance; Immunomodulation; Immunoregulation; Lymphocytes T; Male; Medical schools; Methods; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred CBA; Myeloid cells; Myeloid Cells - metabolism; Nanotechnology; Novels; original-article; Polysaccharides; Ribonucleic acid; RNA; RNA, Small Interfering - chemistry; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Rodents; siRNA; Sizofiran - chemistry; Sizofiran - metabolism; Skin & tissue grafts; Spleen; Splenocytes; Surgery; T cells; T-Lymphocyte Subsets - immunology; Transfection; Transplantation; β-Glucan; Japan
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/gt.2014.119

The CD40/CD154 co-stimulatory pathway is crucial in alloimmune response. We developed a novel small interfering RNA (siRNA) delivery system with a poly-dA extension at the 5′-end of the siRNA sense strand that was stably incorporated into 1,3-β-glucan (schizophyllan, SPG). This was captured and incorporated into dendritic cells (DCs) through its receptor, Dectin-1, specifically silencing CD40 genes (siCD40) to exert immunoregulatory activity. siCD40/SPG-treated CBA mice permanently accepted B10 fully mismatched cardiac allografts. Consistent with graft survival, the infiltration of CD4 + , CD8 + T cells into the graft was lower, and that the numbers of CD40 low CD11c + DCs cells and CD4 + Foxp3 + cells were increased in both the graft and in the recipient spleen. In addition, naive CBA recipients given an adoptive transfer of splenocytes from the primary recipients with siCD40/SPG accepted a heart graft from donor-type B10, but not third-party Balb/c mice. In conclusion, the treatment with siCD40/SPG targeting DCs could generate antigen-specific Tregs, resulting in the permanent acceptance of mouse cardiac allografts. These findings have important implications for clarifying the mechanism underlying the induction of tolerance in DCs, and also highlight the potential of immunomodulation and the feasibility of siRNA-based clinical therapy in the transplantation field.