OX40-OX40L Interaction Promotes Proliferation and Activation of Lymphocytes via NFATc1 in ApoE-Deficient Mice

Jinchuan Yan,Liangjie Xu,Cuiping Wang,Hongling Su,Yao Liang Tang

doi:10.1371/journal.pone.0060854

Abstract

BackgroundOur previous studies have shown that OX40-OX40L interaction regulates the expression of nuclear factor of activated T cells c1(NFATc1) in ApoE−/− mice during atherogenesis. The aim of this study was to investigate whether OX40-OX40L interaction promotes Th cell activation via NFATc1 in ApoE−/− mice.Methods and ResultsThe lymphocytes isolated from spleen of ApoE−/− mice were cultured with anti-CD3 mAb in the presence or absence of anti-OX40 or anti-OX40L antibodies. The expression of NFATc1 mRNA and protein in isolated lymphocytes were measured by real time PCR (RT-PCR) and flow cytometry (FCM), respectively. The proliferation of lymphocytes was analyzed by MTT method,and the expression of IL-2, IL-4 and IFN-γ in the cultured cells and supernatant were measured by RT-PCR and enzyme-linked immunosorbent assary (ELISA), respectively. After stimulating OX40-OX40L signal pathway, the expression of NFATc1 and the proliferation of leukocytes were significantly increased. Anti-OX40L suppressed the expression of NFATc1 in lymphocytes of ApoE−/− mice. Anti-OX40L or the NFATc1 inhibitor (CsA) markedly suppressed the cell proliferation induced by anti-OX40. Moreover, the expression of IL-2 and IFN-γ was increased in lymphocytes induced by OX40-OX40L interaction. Blocking OX40-OX40L interaction or NFATc1 down-regulated the expression of IL-2 and IFN-γ, but didn’t alter the expression of IL-4 in supernatants.ConclusionThese results suggest that OX40-OX40L interaction promotes the proliferation and activation of lymphocytes through NFATc1.

Highlights

Atherosclerosis is a chronic-inflammatory disease in the context of hypercholesterolemia, in which both innate and adaptive immune responses play a role [1,2]
These results suggest that OX40-OX40L interaction promotes the proliferation and activation of lymphocytes through NFATc1
After signals delivered by antigen (Ag) stimulation and costimulatory signals provided by antigen presenting cells (APCs) during T cell activation, inositol 1.4.5-trisphosphate (IP3) induces a rapid increase in intracellular free Ca2+

Summary

Introduction

Atherosclerosis is a chronic-inflammatory disease in the context of hypercholesterolemia, in which both innate and adaptive immune responses play a role [1,2]. Previous studies from our laboratory and others have shown an emerging role of OX40-OX40L interaction in the development of atherosclerotic lesions during atherogenesis [3]. The IP3-Ca2+ directly binds to nuclear factor of activated T (NFAT) transcription factors in the cytoplasm, resulting in their dephosphorylation and subsequent translocation into the nucleus. This translocation leads to diverse cellular physiological functions, such as secretion, cell proliferation, cell growth, differentiation and aging [4]. Our previous studies have shown that OX40-OX40L interaction regulates the expression of nuclear factor of activated T cells c1(NFATc1) in ApoE2/2 mice during atherogenesis. The aim of this study was to investigate whether OX40OX40L interaction promotes Th cell activation via NFATc1 in ApoE2/2 mice

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