Donor antigen-primed regulatory T cells permit liver regeneration and phenotype correction in hemophilia A mouse by allogeneic bone marrow stem cells

Abstract

IntroductionCell replacement therapy may be considered as an alternate approach to provide therapeutic dose of plasma factor VIII (FVIII) in patients with hemophilia A (HA). However, immune rejection limits the use of allogeneic cells in this mode of therapy. Here, we have examined the role of donor major histocompatibility complex (MHC)-stimulated host CD4+CD25+ regulatory T (Treg) cells in suppressing immune responses against allogeneic uncommitted (Lin−) bone marrow cells (BMCs) for correction of bleeding disorder in HA mice.MethodsAllogeneic donor Lin− BMCs were co-transplanted with allo-antigen sensitized Treg cells in HA mice having acetaminophen-induced acute liver injury. Plasma FVIII activity was determined by in vitro functional assay, and correction of bleeding phenotype was assessed on the basis of capillary blood clotting time and tail-clip challenge. The immunosuppression potential of the sensitized Treg cells on CD4+ T cells was studied both in vitro and in vivo. Suppression of inflammatory reactions in the liver against the homed donor cells by sensitized Treg cells was analysed by histopathological scoring. Allo-specificity of sensitized Treg cells and long-term retention of immunosuppression were examined against a third-party donor and by secondary challenge of allogeneic donor cells, respectively. The engraftment and phenotype change of donor BMCs in the liver and their role in synthesis of FVIII and liver regeneration were also determined.ResultsCo-transplantation of allogeneic Lin− BMCs with sensitized Treg cells led to systemic immune modulation and suppression of inflammatory reactions in the liver, allowing better engraftment of allogeneic cells in the liver. Allo-antigen priming led to allo-specific immune suppression even after 1 year of transplantation. Donor-derived endothelial cells expressed FVIII in HA mice, leading to the correction of bleeding phenotype. Donor-derived hepatocyte-like cells, which constitute the major fraction of engrafted cells, supported regeneration of the liver after acute injury.ConclusionsA highly proficient FVIII secreting core system can be created in regenerating liver by transplanting allogeneic Lin− BMCs in HA mice where transplantation tolerance against donor antigens can be induced by in vitro allo-antigen primed Treg cells. This strategy can be beneficial in treatment of genetic liver disorders for achieving prophylactic levels of the missing proteins.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0119-9) contains supplementary material, which is available to authorized users.

JMJD3 aids in reprogramming of bone marrow progenitor cells to hepatic phenotype through epigenetic activation of hepatic transcription factors

“…Male hemophilia A (HA) mice do not synthesize functional factor VIII, so die as a result of blood loss. Our previous studies confirmed the functional improvement of mice as donor derived cells not only involved in the repairmen of damage liver but also they synthesize active factor VIII [ 12 , 22 ]. We hypothesize that erasure of original epigenetic signatures followed by establishment of new epigenetic marks at lineage specific gene promoters by chromatin modifying enzymes, induced in the injured liver micro-environment, direct the change in transcriptional program of uncommitted BM cells in hepatic gene expression program.…”

“…The only study on gene expression analysis of BM-derived hepatocytes through genome-wide expression analysis described the formation of intermediate cells that differ from the hematopoietic and hepatocyte lineages, but no epigenetic modifications in these cells were investigated [ 21 ]. We have shown earlier that uncommitted syngeneic or allogeneic donor BM progenitor cells (Lin - ) are involved in liver regeneration by engraftment and lineage conversion in acute liver injury model of hemophilia A mouse leading to therapeutic correction [ 12 , 22 ]. Lin - cells are composed of both Lin - CD45 + and Lin - CD45 - fractions, both fractions are important for functional regeneration of liver parenchyma and non-parenchyma, without that hemophilic mouse would not survive.…”

Gene Therapy in India- Current Status

“…The main aim is to develop new institutions for gene therapy research, strengthening of existing institutions which have good expertise in this area in order to initiate work in molecular genetics for decreasing the burden of genetic disorders in the country. The pioneer of gene therapy-related research in India is Advanced Centre for Treatment, Research and Education for Cancer (ACTREC) where active work on gene therapy for head and neck cancer using synthetic vectors is being carried out (17). It is heartening to note that scientists in over dozen of labs in India are working hard with small steps in contributing towards gene therapy work as depicted in Table 1 (18)(19)(20)(21)(22)(23)(24).…”