Egr-1, PKC Beta, Signalling and Atherosclerosis

描述（由申请人提供）：立即早期基因，早期生长反应-1（early growth response-1），与急性细胞扰动环境中的适应不良宿主反应机制有关。除了急性应激外，β 1蛋白的上调可能与慢性血管应激有关。与邻近的非动脉粥样硬化斑块相比，在人和鼠的动脉粥样硬化病变中，PD-I的转录物上调，从而表明PD-I在血管应激中的影响可能不限于急性环境，而是PD-I可能影响慢性血管扰动，例如动脉粥样硬化。我们的初步研究支持这一观点，因为真实的时间PCR显示，在6、8、10、14和24周龄时，apo E（0）小鼠与C57 BL/6对照小鼠相比，其睾丸中β-1转录物呈时间依赖性增加。免疫组化结果显示，动脉粥样硬化斑块中主要表达IL-1的细胞是单核吞噬细胞（MP）和平滑肌细胞（SMC）。在14或24周龄时，与apo E（0）动物相比，apo E（0）背景下的纯合子<$A-1（0）小鼠显示主动脉根部动脉粥样硬化显著减少。与此同时，与单纯apo E缺乏的小鼠相比，双（0）小鼠中促炎和促凝血介质（如JE/MCP- 1、IL-1 β、VCAM-1、ICAM-1、组织因子（TF）和派-1）的转录物显著减少（0）。为了检测PKC β轴（急性缺氧时PKC β-1的关键上游调节因子）是否调节慢性血管应激时PKC β-1的调节，我们将纯合子PKC β（0）小鼠与apoE（0）背景进行了交配。在24周龄时，PKC β（0）/apo E（0）与apo E（0）小鼠相比，动脉粥样硬化病变面积明显减少。血浆葡萄糖和胆固醇/甘油三酯水平在β- 1（0）-或PKC β（0）/apo E（0）小鼠与apo E（0）动物之间没有差异，因此暗示β-1和PKC β是动脉粥样硬化的不同方面。我们推测PKC β依赖性上调的β-内酰胺酶-1对加速血管壁的促炎和促血栓形成机制有重要作用;这些过程与动脉粥样硬化的发病机制有关。我们建议剖析PKC β和PKC-1促进高胆固醇血症apo E（0）小鼠病变发展/进展的生化和信号机制，并预期阐明这些因素影响动脉粥样硬化形成的机制可能会突出治疗干预的新靶点。

DESCRIPTION (provided by applicant): The immediate early gene, early growth response-1 (egr-1), is linked to maladaptive host response mechanisms m settings of acute cellular perturbation. In addition to acute stress, up regulation of egr-1 may be linked to chronic vascular stress. Transcripts for egr-1 were up regulated in both human and murine atherosclerotic lesions compared to adjacent non-atheromatous plaque, thereby suggesting that the impact of egr-1 in vascular stress might not be limited to the acute setting, rather that egr-1 might impact on chronic vascular perturbation, such as atherosclerosis. Our preliminary studies support this concept, as real time PCR revealed a time-dependent .increase in egr-1 transcripts in aortae of apo E (0) mice versus C57BL/6 controls at ages 6, 8, 10, 14 & 24 weeks. Immunohistochemistry demonstrated that the principal egr-1 expressing cells in atheromata were mononuclear phagocytes (MP) and smooth muscle cells (SMC). Homozygous egr-1 (0) mice in the apolipoprotein E (apo E) (0) background displayed significantly reduced atherosclerosis at the aortic root compared with apo E (0) animals at 14 or 24 weeks of age. In parallel, transcripts for proinflammatory & procoagulant mediators such as JE/MCP- 1, IL-1beta, VCAM-1, ICAM-1, tissue factor (TF) and PAI-1 were significantly diminished in double (0) mice versus mice solely deficient in apo E (0). To test if the PKCbeta axis, a key upstream regulator of egr-1 in acute hypoxia, modulated regulation of egr-1 in chronic vascular stress, we bred homozygous PKCbeta (0) mice into the apo E (0) background. A striking decrease in atherosclerotic lesion area was evident at age 24 weeks in PKCbeta (0)/apo E (0) vs apo E (0) mice. Levels of plasma glucose and cholesterol/triglyceride did not differ between egr- 1 (0)- or PKCbeta (0)/apo E (0) mice versus apo E (0) animals, thus implicating egr-1 and PKCbeta as distinct facets in atherosclerosis. We hypothesize that PKCbeta-dependent up regulation of egr-1 contributes importantly to acceleration of proinflammatory and prothrombotic mechanisms in the vessel wall; processes linked to the pathogenesis of atherosclerosis. We propose to dissect the biochemical and signaling mechanisms by which PKCbeta and egr-1 contribute to lesion development/progression in hypercholesterolemic apo E (0) mice and anticipate that elucidation of the mechanisms by which these factors impact on atherogenesis may highlight new targets for therapeutic intervention.