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Prevention of rejection of allogeneic endothelial cells in a biohybrid lung by silencing HLA-class I expression
journal contributionposted on 15.03.2019 by Bettina Wiegmann, Constanca Figueiredo, Christiane Gras, Michael Pflaum, Sabrina Schmeckebier, Sotiris Korossis, Axel Haverich, Rainer Blasczyk
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Variability in Human Leukocyte Antigens (HLA) remains a hurdle to the application of allogeneic cellular products. Due to insufficient autologous endothelial cell harvesting for the biohybrid lung, allogeneic human cord blood derived endothelial cells (HCBEC) were used for the endothelialization of poly-4-methyl-1-pentene (PMP) gas exchange membranes. Therefore, HLA class I expression was silenced stably in HCBECs to prevent rejection. The capacity of HLA class I-silenced HCBEC to abrogate allogeneic immune responses, their functional properties and suitability for endothelialization of PMP membranes were investigated. Delivery of β2-microglobulin (β2m)-specific shRNAs reduced β2m mRNA levels by up to 90% and caused a knockdown of HLA class I expression by up to 85%. HLA-silenced HCBEC abrogated T-cell responses and escaped antibody-mediated complement-dependent cytotoxicity. The EC phenotype and cytokine secretion profiles between HLA-expressing or -silenced HCBEC remained unaltered. EC specific activation (e.g. ICAM) and thrombogenic markers (e.g. thrombomodulin) remained unaffected by HLA-silencing, but their expression was upregulated by TNFα-stimulation. Furthermore, HLA-silenced HCBECs showed high proliferation rates and built an EC monolayer onto PMP membranes. This study represents a new therapeutic concept in the field of cell and organ transplantation and may bring the bioartificial lung as an alternative to lung transplantation closer to reality.
This work was partly supported by funding by the Cluster of Excellence REBIRTH (From Regenerative Biology to Reconstructive Therapy EXC 62/1) (Unit 4.1 and 6.3), as well as by the German Center for Lung Research (DZL) (DZL: 82DZL00201), Lower Saxony Center for Biomedical Technology (NIFE) and German Research Foundation (WI 4088/1-1).
- Mechanical, Electrical and Manufacturing Engineering