TRANSPLANTATION AND CELLULAR ENGINEERING
Silencing the expression of platelet endothelial cell adhesion molecule-1 prevents allogeneic T-cell cytotoxicity
Article first published online: 12 MAY 2010
© 2010 American Association of Blood Banks
Volume 50, Issue 9, pages 1988–2000, September 2010
How to Cite
Jaimes, Y., Figueiredo, C. and Blasczyk, R. (2010), Silencing the expression of platelet endothelial cell adhesion molecule-1 prevents allogeneic T-cell cytotoxicity. Transfusion, 50: 1988–2000. doi: 10.1111/j.1537-2995.2010.02677.x
- Issue published online: 1 SEP 2010
- Article first published online: 12 MAY 2010
- Received for publication November 13, 2009; revision received February 19, 2010, and accepted February 23, 2010.
BACKGROUND: After solid organ transplantation, the endothelium is the first allorecognition checkpoint of the recipient's immune system. A major player at this interface is the platelet endothelial cell adhesion molecule-1 (PECAM-1), which is an immunoglobulin-like glycoprotein, involved in white blood cell migration, cellular adhesion, and signal transduction.
STUDY DESIGN AND METHODS: The potential of preventing allorecognition at this interface was explored by knocking down PECAM-1 expression using RNA interference. Lentiviral-based vectors encoding short-hairpin RNA sequences specific for PECAM-1 transcripts were used for the transduction of monocytic and endothelial cell lines.
RESULTS: Expression of PECAM-1 decreased by up to 80% at mRNA and protein levels on monocytic and endothelial cell lines. Antigen-binding capacity assays likewise showed up to 80% reduction of PECAM-1 expression on cell surfaces. In allogeneic T-cell stimulation assays, T cells stimulated with PECAM-1–silenced monocytes had granzyme B mRNA levels up to 85% lower than those in T cells stimulated with monocytes expressing nonspecific shRNA. Also, T-cell cytotoxicity showed to decrease significantly against PECAM-1–silenced monocytes versus those nonsilenced for PECAM-1. Moreover, the former T cells did not secrete interferon-γ and exhibited reduced proliferation.
CONCLUSION: These findings suggest that permanent silencing of PECAM-1 expression is feasible and contributes to efficiently inhibiting the cytotoxic T-cell response to allogeneic target cells. Thus, targeting both the immunologic synapse at the regulatory interface and the lymphocyte migration might provide a new strategy to overcome allogeneic transplant rejection.