SUPPRESSORS OF CYTOKINE SIGNALING AND IL-10 INHIBITORY EFFECT IN LYME DISEASE

Tulane University Of Louisiana, New Orleans LA

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Abstract

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have reported on experiments in vitro showing that in response to live Borrelia burgdorferi (Bb) and its purified outer surface lipoprotein A (L-OspA), IL-10 dampens the prototypic IL-6, IL-12, TNF-alpha and IL-1beta inflammatory responses in mouse J774 macrophages. We also showed that mouse macrophages incubated with IL-10 together with either live Bb or L-OspA additively augmented the expression of the suppressor of cytokine signaling (SOCS) 3 in these cells. In this study we first used a chemokine/cytokine multiplex approach to determine the extent of the IL-10-mediated inhibition of inflammatory mediators in macrophages in response to live Bb and L- OspA. RNA interference was then used to silence socs3 gene expression in macrophages to determine the effect of silencing on IL-10 inhibition of inflammatory mediators in response to live Bb and L-OspA. Multiplex analysis revealed that IL-10 significantly (P0.05) down-regulated the production of several cytokines (TNF-alpha, IL-12, IL-6, IL-1alpha, IL-1beta, IL-9) and chemokines (G-CSF, CXCL1, CXCL5, CXCL10 and CCL5) in macrophages stimulated with live Bb or L-OspA. In all instances live Bb induced higher levels of cytokines and chemokines than did L-OspA. All mediators induced by both stimulants in macrophages were down-modulated by IL-10 in a similar fashion and correlated with enhanced SOCS3 expression in these cells. Silencing of SOCS3 expression in macrophages abrogated the IL-10-anti-inflammatory actions against IL-6 production in response to live Bb and L-OspA. This study demonstrates that SOCS3 in part mediates the IL-10 anti-inflammatory effect in macrophages stimulated with live B. burgdorferi spirochetes and lipoproteins. Comparisons of macrophage genome-wide transcriptomics data before and after the silencing of SOCS3 will ultimately identify the extent of the SOCS3-mediated anti-IL-10 inhibitory effect in response to B. burgdorferi.