REGULATION OF SOCS EXPRESSION IN MACROPHAGES IN RESPONSE TO BORRELIA AND IL-10

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们最近证实，伯氏疏螺旋体活菌(BB)或纯化的伯氏疏螺旋体外表面脂蛋白(L-OspA)单独或与IL-10联合刺激小鼠J774巨噬细胞可增强细胞因子信号转导抑制因子(SOCS)1和SOCS3的表达。我们推测，伯氏杆菌单独或与IL-10共同诱导巨噬细胞SOCS1/SOCS3的表达在莱姆病病程中的炎症控制中具有重要的功能，SOCS1/SOCS3可能是巨噬细胞炎性细胞因子信号的直接调节器。为了验证这一假设，我们检测了SOCS抑制干扰素-γ对磷酸化的STAT(信号转导和转录激活因子)1蛋白的激活和DNA结合活性的能力。我们专注于干扰素-γ信号，因为在免疫反应的初始阶段，这种细胞因子在巨噬细胞的激活中起着关键作用。活体BB和L-OspA单独或与IL-10合用均不能激活巨噬细胞STAT1的磷酸化。然而，这些刺激剂对干扰素-g的反应是对pSTAT1激活的抑制2-5倍。这与活体BB和L-OspA诱导这些细胞SOCS1/SOCS3表达增强有关。活体BB联合IL-10、L-OspA单独或联合IL-10可显著抑制干扰素-γ诱导的巨噬细胞pSTAT1的核转位(P<0.002)。巨噬细胞中SOCS的过表达对干扰素-γ产生的一氧化氮(NO)没有影响，提示SOCS不是巨噬细胞产生NO的介质。本研究表明，在疾病早期，伯氏杆菌诱导的SOCS1/SOCS3可能在功能上抑制巨噬细胞的激活，干扰宿主的免疫反应。

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 recently demonstrated that stimulation of mouse J774 macrophages with either live Borrelia burgdorferi spirochetes (Bb) or Bb purified outer surface lipoprotein (L-OspA) alone or combined with IL-10 augmented the expression of the suppressor of cytokine signaling (SOCS)1 and SOCS3 in these cells. We hypothesized that the expression of SOCS1/SOCS3 induced by B. burgdorferi alone or together with IL-10 in macrophages is functionally important in the control of inflammation during the course of Lyme disease; SOCS1/SOCS3 would act as direct modulators of inflammatory cytokine signaling in macrophages. To test this hypothesis, we examined the ability of SOCS to inhibit the activation and DNA binding activities of phosphorylated STAT (signal transducer and activator of transcription) 1 protein in response to IFN-gamma. We focused on IFN-gamma signaling because this cytokine plays a pivotal role in the activation of macrophages during the initial phase of the immune response. Live Bb and L-OspA alone or combined with IL-10 did not activate the phosphorylation of STAT1 in macrophages at all time points examined (0-60 mins). However, these stimulants inhibited pSTAT1 activation by 2- to 5-fold in response to IFN-g. This correlated with the enhanced expression of SOCS1/SOCS3 induced in these cells by live Bb and L-OspA. Live Bb combined with IL-10, L-OspA alone or combined with IL-10 significantly (P 0.002 to 0004) inhibited the nuclear translocation of pSTAT1 in macrophages in response to IFN-gamma. SOCS overexpression in macrophages had no effect on nitric oxide (NO) production by IFN-gamma, suggesting that SOCS is not a mediator of NO production by IFN-gamma in macrophages. This study demonstrates that SOCS1/SOCS3 induced by B. burgdorferi may functionally suppress macrophage activation and interfere with the host immune response during the early phase of disease.