Durable engraftment of genetically modified FVIII-secreting autologous bone marrow stromal cells in the intramedullary microenvironment

作者：Lee Sze Sing; Sivalingam Jaichandran; Nirmal Ajit J; Ng Wai Har; Kee Irene; Song In Chin; Kiong Chin Yong; Gales Kristoffer A; Chua Frederic; Pena Edgar M; Ogden Bryan E; Kon Oi Lian^*

来源：JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, 2018, 22(7): 3698-3702.

DOI：10.1111/jcmm.13648

• autologous stem cell transplantation
• bone marrow stromal cells
• cell therapy
• engraftment
• factor VIII
• gene targeting
• haemophilia A
• tissue microenvironment

Genetically modified FVIII-expressing autologous bone marrow-derived mesenchymal stromal cells (BMSCs) could cure haemophilia A. However, culture-expanded BMSCs engraft poorly in extramedullary sites. Here, we compared the intramedullary cavity, skeletal muscle, subcutaneous tissue and systemic circulation as tissue microenvironments that could support durable engraftment of FVIII-secreting BMSC invivo. A zinc finger nuclease integrated human FVIII transgene into PPP1R12C (intron 1) of culture-expanded primary canine BMSCs. FVIII-secretory capacity of implanted BMSCs in each dog was expressed as an individualized therapy index (number of viable BMSCs implantedxFVIII activity secreted/million BMSCs/24hours). Plasma samples before and after implantation were assayed for transgenic FVIII protein using an anti-human FVIII antibody having negligible cross-reactivity with canine FVIII. Plasma transgenic FVIII persisted for at least 48weeks after implantation in the intramedullary cavity. Transgenic FVIII protein levels were low after intramuscular implantation and undetectable after both intravenous infusion and subcutaneous implantation. All plasma samples were negative for anti-human FVIII antibodies. Plasma concentrations and durability of transgenic FVIII secretion showed no correlation with the therapy index. Thus, the implantation site microenvironment is crucial. The intramedullary microenvironment, but not extramedullary tissues, supported durable engraftment of genetically modified autologous FVIII-secreting BMSCs.

• 出版日期2018-7