Kidney Week

Abstract: SA-OR094

Simvastatin Modulates the Immunoregulatory Phenotype of Vascular Endothelial Cells

Session Information

• Transplantation: Back to the Basics
  October 27, 2018 | Location: 6D, San Diego Convention Center
  Abstract Time: 05:42 PM - 05:54 PM

Category: Transplantation

• 1801 Transplantation: Basic

Authors

• Agur, Timna, Boston Children’s Hospital, Boston, Massachusetts, United States

Timna Agur, MD



Timna Agur, MD.MSc. Dr. Timna Agur is an adult-nephrologist. She earned her BSc and MSc from Ben-Guryon University in Beer-Sheva, and her MD from Hadassah Medical School, the Hebrew University, Jerusalem, Israel. She completed her residency in Internal Medicine in Meir Medical Center, Kfar-Saba, Israel, where she had also done her fellowship in Nephrology and Hypertension. During the last two years, Dr Agur has been a post-doctoral fellow in transplantation immunology at the Transplant Research Program and the Division of Nephrology at Boston Children’s Hospital, Harvard Medical School, Boston, US. Dr. Agur will assume the position of a staff member at the Nephrology and Kidney Transplantation Institute at Rabin Medical Center, Israel.

• Ghosh, Chandra C., Boston Children’s Hospital, Boston, Massachusetts, United States

Chandra C. Ghosh,

• Wedel, Johannes, Boston Children’s Hospital, Boston, Massachusetts, United States

Johannes Wedel,

• Briscoe, David M., Boston Children’s Hospital, Boston, Massachusetts, United States

David M. Briscoe,

Background

Evidence suggests that HMG-CoA reductase inhibitors (statins) reduce the incidence of acute and chronic allograft rejection and have immunomodulatory effects. However, their mechanism of function to regulate alloimmunity is poorly understood. We hypothesize that statins modulate the immunogenicity of donor graft endothelial cells (EC) and the costimulation of recipient CD4+ Teffector cells thereby promoting a pro-tolerogenic intragraft microenvironment.

Methods

Pooled populations of CD4+T cells and memory CD45RO+ subsets were isolated from PBMC, and were co-cultured with untreated human umbilical vein EC (HUVEC) or EC pre-treated with simvastatin (Simva, 0.1-10μM 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 using either [3H] thymidine incorporation or CFSE dilution by FACS. Released cytokines were analyzed by Luminex and by ELISPOT, and the direct effect of Simva on the phenotype of EC was evaluated by RNAseq and validated by qPCR. Controls were Simva-treated fibroblasts.

Results

We found a significant reduction (P<0.001, n=6) in the proliferation of CD4+T cells following coculture with Simva-pretreated EC vs. untreated cells. Furthermore, inhibition of memory CD4+T cell proliferation was dose dependent using up to five concentrations of simva (0.1-10µM, n=3). Multianalyte luminex assays of coculture supernatants revealed a reduction in several pro-inflammatory cytokines, and ELISPOT assays confirmed a notable effect on the reduction of IL-2, IFNg and IL-6 production following coculture with Simva-pretreated EC vs. untreated cells. In contrast, fibroblasts pretreated with Simva failed to inhibit PHA-induced proliferation of CD4+T cells as a control, indicating that there are cell intrinsic effects of Simva on the EC phenotype. To determine mechanism, we evaluated RNAseq and performed mRNA gene arrays on Simva-treated EC vs untreated and found increased expression of immunoregulatory genes including LGALS family molecules and reduced expression of IL-6, IL-8 and OX40L.

Conclusion

Simvastatin modulates the immunogenicity of EC and their function in the activation of memory CD4⁺T cells. These studies support the use of simvastatin as an adjunct immunomodulatory therapy to augment tolerance and promote long-term graft survival.

Funding

• Other NIH Support