A common complication in autoimmune connective tissue diseases is vascular involvement 12. A reduction in the number of capillaries has been observed associated with endothelial swelling, basement membrane thickening and hyperplasia of the intima with infiltration of inflammatory cells into the skin 12. Considering this scenario in mind, one can hypothesize that IFI16 is involved in the early steps of inflammation resulting in EC activation – a necessary condition for the development of autoimmune diseases. Fulvestrant in vitro The aim of this study was to verify whether
inflammatory molecule induction by IFI16 is confined to adhesion molecules, such as ICAM-1, or if it can also be extended to proinflammatory NVP-LDE225 chemokines that are responsible for inflammatory cell recruitment, such as CCL4, CCL5 and CCL20, thereby reinforcing the physiological relevance of IFI16 in the early steps of inflammation. We have previously analyzed transcriptomes from EC overexpressing IFI16 and found that IFI16 upregulates a complex
array of cellular genes encoding inflammatory molecules responsible for leukocyte recruitment 9. Moreover, we showed that IFI16 triggers the expression of EC ICAM-1 9 – an adhesion molecule involved in the enrolment of cells at the site of inflammation during the first steps of inflammation 13. In this study, in order to determine whether IFI16 also induces the secretion of chemokines and cytokines, we first analyzed the IFI16 secretome for 174 common chemokines, cytokines and growth factors using RayBio human
cytokine array G Series 2000 Ab arrays. A comparison of the supernatants from cultured human umbilical vein EC (HUVEC)-overexpressing IFI16 with those C-X-C chemokine receptor type 7 (CXCR-7) from control HUVEC cultures infected with the LacZ transgene indicated 12 significantly induced molecules (Table 1). The most abundant inflammatory factors in the IFI16 secretome included the chemokines/cytokines CCL3, CCL4, CCL5, CCL20 and IL-1β, along with the growth regulatory factor amphiregulin (AREG). Consistent with the previous results showing induction of ICAM-1 at the transcriptional level, IFI16 overexpression also induced the expression of the soluble form of ICAM-1. Validation of the protein array analysis for some of the proteins identified from the secretome analysis was performed using real-time PCR (RT-PCR). Primer sequences were designed using the program qPrimerDepot (http://primerdepot.nci.nih.gov/) directed at both the 3′ and 5′ ends of the gene sequence. The gene-specific primers used in this study are listed in Table 2. RT-PCR analysis largely confirmed secretome analysis. As shown in Fig. 1, IFI16 modulates the expression of endothelial genes, such as ICAM-1, implicated in the early steps of inflammation.