TY - JOUR
T1 - Suppression of HLA expression by lentivirus-mediated gene transfer of siRNA cassettes and in vivo chemoselection to enhance hematopoietic stem cell transplantation
AU - Hacke, Katrin
AU - Falahati, Rustom
AU - Flebbe-Rehwaldt, Linda
AU - Kasahara, Noriyuki
AU - Gaensler, Karin M.L.
N1 - Funding Information:
Acknowledgments We would like to acknowledge the researchers in the Kasahara and Gaensler Laboratories who have contributed to this work: In the Kasahara Laboratory, Dr. Kazunori Haga and Nathan Lemp contributed equally as the primary researchers who performed the studies described in this review; Dr. Christopher R. Logg designed the original shRNA constructs, and supervised their cloning and testing in lentiviral vectors by Jill Nagashima; Dr. Emmanuelle Faure-Kumar performed large-scale vector production; Dr. Renata Stripecke provided assistance in data analysis and helpful discussion, and the UCLA Vector Shared Resource/Core facility provided technical assistance. We would also like to thank our collaborators, Dr. James Cicciarelli and Dr. Robert Mendez at the National Institute of Transplantation (NIT) at St. Vincent’s Medical Center in Los Angeles, Dr. German G. Gomez and Dr. Carol Kruse at the Sidney Kimmel Cancer Center in San Diego, and Dr. William McBride and Dr. Richard Gatti at the UCLA Center for Biological Radioprotectors. Work in the Kasahara laboratory was supported in part by the NIAID-funded UCLA Center for Biological Radioprotectors (U19 AI 067769), the NIT Foundation, and the California Institute for Regenerative Medicine (RS1-00402-01). Researchers in the Gaensler laboratory who have contributed to this work include Dr. Linda Flebbe-Rehwaldt who developed the initial neonatal transplantation model including the non-ablative preparative regimen and in vivo chemoselection protocols; Dr. Rustom Falahati performed the in vitro chemoselection assay, optimized conditions for lentiviral transduction and transplantation of transduced HSC, and performed FACS and immunological analyses. We would like to thank our collaborators Dr. Stanton Gerson at the Department of Medicine, Division of Hematology–Oncology, Case Western Reserve University, Cleveland, Ohio, who provided the MAG vector, and Dr. William Murphy at the Department of Microbiology and Immunology, University of Nevada, Reno, Nevada for valuable advice. The work in the Gaensler laboratory was supported by NIH 5R21 DK069430-02, NIH 1R01HL082665-01A2, and a UCSF Bridge Funding award.
PY - 2009
Y1 - 2009
N2 - Current approaches for hematopoietic stem cell (HSC) and organ transplantation are limited by donor and host-mediated immune responses to allo-antigens. Application of these therapies is limited by the toxicity of preparative and post-transplant immunosuppressive regimens and a shortage of appropriate HLA-matched donors. We have been exploring two complementary approaches for genetically modifying donor cells that achieve long-term suppression of cellular proteins that elicit host immune responses to mismatched donor antigens, and provide a selective advantage to genetically engineered donor cells after transplantation. The first approach is based on recent advances that make feasible targeted down-regulation of HLA expression. Suppression of HLA expression could help to overcome limitations imposed by extensive HLA polymorphisms that restrict the availability of suitable donors. Accordingly, we have recently investigated whether knockdown of HLA by RNA interference (RNAi) enables allogeneic cells to evade immune recognition. For efficient and stable delivery of short hairpin-type RNAi constructs (shRNA), we employed lentivirus-based gene transfer vectors that integrate into genomic DNA, thereby permanently modifying transduced donor cells. Lentivirus-mediated delivery of shRNA targeting pan-Class I and allele-specific HLA achieved efficient and dose-dependent reduction in surface expression of HLA in human cells, and enhanced resistance to allo-reactive T lymphocyte-mediated cytotoxicity, while avoiding non-MHC restricted killing. Complementary strategies for genetic engineering of HSC that would provide a selective advantage for transplanted donor cells and enable successful engraftment with less toxic preparative and immunosuppressive regimens would increase the numbers of individuals to whom HLA suppression therapy could be offered. Our second strategy is to provide a mechanism for in vivo selection of genetically modified HSC and other donor cells. We have uniquely combined transplantation during the neonatal period, when tolerance may be more readily achieved, with a positive selection strategy for in vivo amplification of drug-resistant donor HSC. This model system enables the evaluation of mechanisms of tolerance induction to neo-antigens, and allogeneic stem cells during immune ontogeny. HSC are transduced ex vivo by lentivirus-mediated gene transfer of P140K-O 6-methylguanine-methyltransferase (MGMTP140K). The MGMTP140K DNA repair enzyme confers resistance to benzylguanine, an inhibitor of endogenous MGMT, and to chloroethylating agents such as BCNU. In vivo chemoselection enables enrichment of donor cells at the stem cell level. Using complementary approaches of in vivo chemoselection and RNAi-induced silencing of HLA expression may enable the generation of histocompatibility- enhanced, and eventually, perhaps "universally" compatible cellular grafts.
AB - Current approaches for hematopoietic stem cell (HSC) and organ transplantation are limited by donor and host-mediated immune responses to allo-antigens. Application of these therapies is limited by the toxicity of preparative and post-transplant immunosuppressive regimens and a shortage of appropriate HLA-matched donors. We have been exploring two complementary approaches for genetically modifying donor cells that achieve long-term suppression of cellular proteins that elicit host immune responses to mismatched donor antigens, and provide a selective advantage to genetically engineered donor cells after transplantation. The first approach is based on recent advances that make feasible targeted down-regulation of HLA expression. Suppression of HLA expression could help to overcome limitations imposed by extensive HLA polymorphisms that restrict the availability of suitable donors. Accordingly, we have recently investigated whether knockdown of HLA by RNA interference (RNAi) enables allogeneic cells to evade immune recognition. For efficient and stable delivery of short hairpin-type RNAi constructs (shRNA), we employed lentivirus-based gene transfer vectors that integrate into genomic DNA, thereby permanently modifying transduced donor cells. Lentivirus-mediated delivery of shRNA targeting pan-Class I and allele-specific HLA achieved efficient and dose-dependent reduction in surface expression of HLA in human cells, and enhanced resistance to allo-reactive T lymphocyte-mediated cytotoxicity, while avoiding non-MHC restricted killing. Complementary strategies for genetic engineering of HSC that would provide a selective advantage for transplanted donor cells and enable successful engraftment with less toxic preparative and immunosuppressive regimens would increase the numbers of individuals to whom HLA suppression therapy could be offered. Our second strategy is to provide a mechanism for in vivo selection of genetically modified HSC and other donor cells. We have uniquely combined transplantation during the neonatal period, when tolerance may be more readily achieved, with a positive selection strategy for in vivo amplification of drug-resistant donor HSC. This model system enables the evaluation of mechanisms of tolerance induction to neo-antigens, and allogeneic stem cells during immune ontogeny. HSC are transduced ex vivo by lentivirus-mediated gene transfer of P140K-O 6-methylguanine-methyltransferase (MGMTP140K). The MGMTP140K DNA repair enzyme confers resistance to benzylguanine, an inhibitor of endogenous MGMT, and to chloroethylating agents such as BCNU. In vivo chemoselection enables enrichment of donor cells at the stem cell level. Using complementary approaches of in vivo chemoselection and RNAi-induced silencing of HLA expression may enable the generation of histocompatibility- enhanced, and eventually, perhaps "universally" compatible cellular grafts.
KW - Busulfan (BU)
KW - Human leukocyte antigen (HLA)
KW - MGMT-2A-GFP lentivirus vector (MAG)
KW - Major histocompatibility complex (MHC)
KW - O-methylguanine- DNA-methyltransferase (MGMT)
KW - RNA interference (RNAi)
KW - Short hairpin-type RNAi (shRNA)
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U2 - 10.1007/s12026-008-8088-z
DO - 10.1007/s12026-008-8088-z
M3 - Review article
C2 - 19048410
AN - SCOPUS:69849105156
VL - 44
SP - 112
EP - 126
JO - Immunologic Research
JF - Immunologic Research
SN - 0257-277X
IS - 1-3
ER -