Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.
Type-1 Interferon Does Not Directly Impair Endothelial Cell Function in Vitro: Implications for Cardiovascular Models of Systemic Lupus Erythematosus.
Reynolds1, John A., Ray1, David W., O'Neill1, Terence, Alexander1, M. Yvonne, Bruce2, Ian N.
Systemic Lupus Erythematosus (SLE) is associated with a significantly increased risk of cardiovascular disease (CVD). Type-1 interferon (IFN) is the dominant inflammatory cytokine in SLE and IFN treatment can induce endothelial dysfunction in patients with viral hepatitis. Furthermore, IFN impairs the function of endothelial progenitor cells (EPCs) in vitro, replicating a phenotype similar to that seen in EPCs from lupus patients. The mechanism by which IFN impairs endothelial cell function is unknown. We aimed to determine the effect of IFN upon endothelial cells in order to establish an in vitro endothelial model relevant to SLE.
Human aortic endothelial cells (HAoECs) were cultured in standard conditions. For proliferation experiments, the effect of IFNa2b was studied either by counting cell nuclei in random fields or by MTT assay. An Affymetrix GeneChip Human Exon 1.0 ST Array was used to determine changes in gene expression at 6 hours following addition of IFNa2b. Nitric oxide bioavailability in the cell culture supernatant was measured using a Griess assay (total nitrate and nitrite) at 6 and 24 hours. The ability of HAoECs to form capillary networks in Matrigel at 18 hours and in type-1 rat tail collagen gels at up to 48 hours was studied in the presence or absence of IFNa2b.
IFNa2b at concentrations of 0.1100ng/ml had no effect on HAoEC proliferation measured by either cell count or MTT assay at up to 72 hours (n=3 for each). The expression of 164 genes was significantly changed (>2-fold change, q<0.2) by the addition of 10ng/ml IFNa2b at 6 hours. These genes were primarily those previously reported to be regulated by IFNa or those involved in cellular response to virus (e.g. IFIT1, IFI44L, MX1 and CXCL10).
Nitric oxide availability was not changed at up to 24 hours by the addition of IFNa2b (n=3). The formation of 2-dimensional capillary networks in Matrigel was variable and not consistently impaired by the addition of 10ng/ml IFN. Furthermore the development of 3-dimensional networks in collagen was not disrupted by the addition of IFNa2b to either the gel or the culture media.
Interferon-a2b did not affect the function of human aortic endothelial cells in vitro. Gene expression was not influenced beyond those genes involved in IFN signalling or in response to virus. We propose therefore, that the reported effects of IFN on EPC function do not extend to mature human endothelial cells. This has implications for the development of in vitro endothelial models relevant to SLE and further work should focus upon the role of IFN in EPC differentiation and function.
To cite this abstract, please use the following information:
Reynolds, John A., Ray, David W., O'Neill, Terence, Alexander, M. Yvonne, Bruce, Ian N.; Type-1 Interferon Does Not Directly Impair Endothelial Cell Function in Vitro: Implications for Cardiovascular Models of Systemic Lupus Erythematosus. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :78