Transplant Research Program, Dept of Pediatrics
Boston Children's Hospital
Simvastatin modulates the immunoregulatory phenotype of vascular endothelial cells
Timna Agur1, Johannes Wedel1, Daniel Goodman1, Chandra Ghosh1, David Briscoe1.
1Transplant Research Program and the Division of Nephrology, Boston Childrens Hospital and Harvard Medical School, Boston, MA, United States
Introduction: There is compelling evidence in the transplant literature to suggest that cholesterol-lowering HMG-CoA reductase inhibitors (statins) are immunomodulatory. While statins target endothelial cells (EC), little is known about their ability to modulate EC immunogenicity or EC-leukocyte interactions that function in both the initiation as well as the progression of transplant rejection. We hypothesize that statins modulate the immunoregulatory phenotype and function of donor graft endothelial cells and consequently their interactions with recipient CD4+T cells.
Materials and Methods: The effect of simvastatin (Simva 1µM or 10µM for up to 24hrs) on the phenotype of EC was evaluated by full transcriptome RNAseq profiling using custom barcodes, and genes of interest were validated by qPCR. For functional assays, memory CD45RO+ subpopulations of CD4+ T cells were co-cultured with untreated human umbilical vein EC (HUVEC) or EC pre-treated with Simva (0.1-10mM for 24 hrs) in the presence of mitogen (PHA 0.1-0.3µg/ml). The ability of EC to transcostimulate CD4+T cell proliferation was measured after 72 hours and effector cytokine responses were analyzed by ELISPOT and by multianalyte Luminex in coculture supernatants.
Results: RNA sequencing revealed potent effects of Simva on the regulation of EC activation responses, inducing a significant reduction in IL-8, GITR-L, MCP-1 and OX40L expression. In addition, Simva markedly increased the expression of several immunoregulatory proliles that include LGALS3, LGALS9 and IL10R. In transcostimulation assays, the co-culture of memory CD4+T cells with Simva-pretreated EC reduced proliferative responses (up to 69%, P<0.001, n=6) in a dose-dependent manner using concentrations from 0.1-10µM vs. untreated EC. Furthermore, the production of several pro-inflammatory cytokines was reduced following CD4+ T cell coculture with Simva-pretreated EC (vs. untreated EC), and ELISPOT assays confirmed notable effects on IFNg, IL-6 and IL-2 secretion. Pre-treatment of EC with L-mevalonate in combination with Simva reversed the immunomodulatory effect of Simva on the expression of immunoregulatory genes by EC, and on memory CD4+T cell proliferation in the transcostimulation assay.
Conclusion: Simvastatin modulates the immunogenicity of EC, including the expression of immunoregulatory molecules and their function in the transcostimulation of CD4+T cells. Furthermore, these effects are elicited through inhibition of the mevalonate pathway in EC, which may have implications for diet and post transplant survival. Our findings strongly support the use of simvastatin as an adjunct immunomodulatory therapy to augment tolerance and promote long-term graft survival.
Isabella Julian Forrest Fund for Post Kidney Transplant Research. Casey Lee Ball Foundation.
12:00 - 12:30
|Immunology||Overview of basic transplant immunology||Stanley Park - Ballroom 2|
10:00 - 11:00
|Basic Science: Novel Understandings in the Immune Response||Simvastatin modulates the immunoregulatory phenotype of vascular endothelial cells||Seymour Room|