Endothelial Cell Biology in Inflammation

我们的总体目标是阐明内皮细胞（EC）的功能和转录组特化， 从血液中募集淋巴细胞，并通过高水平的淋巴细胞归巢来确定淋巴细胞归巢的新机制。 内皮小静脉（HEV）。 除了与毛细血管（CAP）和其他EC的差异外，HEV还显示组织特异性表达 控制淋巴细胞器官特异性的血管"地址素"、粘附受体和趋化因子 归航为了鉴定定义和编程HEV特化的基因和转录网络，我们 启动了淋巴组织HEV和CAP的全基因组表达研究。初步的数据挖掘 确定了控制淋巴细胞募集的新的候选机制，包括一种新的血管 B细胞归巢地址素和渗出脂质调节剂代谢基因的HEV表达。 目的包括：1）全面分析节段性（HEV vs CAP）和组织特异性（皮肤- 引流与肠系膜淋巴结和派伊尔集合淋巴结）HEC的转录特化，并定义 HEC对免疫的反应。来自解离PLN、MLN和PP的HEC和CAP将通过FACS分选 基于EC子集标记，以及提交用于全基因组表达谱分析的RNA。转录 HEC对极化免疫应答的应答将通过比较静息状态下的HEV和CAP来定义。 与免疫LN比较。2)为了阐明HEV合成一种新的 碳水化合物血管地址素用于B细胞归巢。我们的基因表达数据导致发现了一种新的Gal β 2，6 B细胞凝集素Siglec2（CD22）的唾液酸转移酶依赖性PP HEV配体。我们将使用CD22-Fc结合 在St6gal 1、Cmah和CHST 2 ± 4磺基转移酶敲除小鼠的研究中， HEV表达的聚糖修饰酶在新型地址素合成中的作用。3)为了验证这个假设， HEV相关脂质代谢产物调节淋巴细胞从HEC迁移。基于转录分析 HEC和周围细胞的酶表达，我们假设脂质化学引诱物的梯度 通过HEV参与淋巴细胞募集。短期归巢期间的淋巴细胞渗出将是 定量，以及淋巴细胞受体缺陷和/或靶向代谢抑制的影响。 将评估受体淋巴结中的通路。 对HEV和CAP转录组的综合分析将开辟新的研究领域， 血管生物学和免疫学。阐明淋巴细胞募集的血管控制机制 可能会导致新的目标和方法控制自身免疫性和其他病理性炎症。

Our overall goal is to elucidate the functional and transcriptomic specialization of endothelial cells (EC) that recruit lymphocytes from the blood, and to define novel mechanisms involved in lymphocyte homing via high endothelial venules (HEV). In addition to differences from capillary (CAP) and other EC, HEV display tissue-specific expression of vascular “addressins”, adhesion receptors and chemokines that control the organ specificity of lymphocyte homing. To identify genes and transcriptional networks that define and program HEV specialization, we have initiated whole genome expression studies of lymphoid tissue HEV and CAP. Preliminary data mining has identified novel candidate mechanisms for the control of lymphocyte recruitment, including a novel vascular addressin for B cell homing and HEV expression of genes for metabolism of lipid regulators of diapedesis. Aims include: 1) To comprehensively analyze the segmental (HEV vs CAP) and tissue-specific (skin- draining vs mesenteric lymph node and Peyer’s patch) transcriptional specialization of HEC, and to define the response of HEC to immunization. HEC and CAP from dissociated PLN, MLN and PP will be sorted by FACS based on EC subset markers, and RNA submitted for whole genome expression profiling. The transcriptional response of HEC to polarizing immune responses will be defined by comparison of HEV and CAP from resting vs immunized LN. 2) To elucidate the biosynthetic machinery required for HEV synthesis of a novel carbohydrate vascular addressin for B cell homing. Our gene expression data led to discovery of a Gal2, 6 sialyltransferase-dependent PP HEV ligand for the B cell lectin Siglec2 (CD22). We will use CD22-Fc binding in studies of St6gal1, Cmah and CHST 2±4 sulfotransferase knockout mice to test the hypothesized roles of HEV-expressed glycan-modifying enzymes in synthesis of the novel addressin. 3) To test the hypothesis that HEV-associated lipid metabolites regulate lymphocyte migration from HEC. Based on transcriptional analyses of enzyme expression by HEC and surrounding cells, we hypothesize that gradients of lipid chemoattractants participate in lymphocyte recruitment via HEV. Lymphocyte diapedesis during short term homing will be quantified, and the effects of deficiency in lymphocyte receptors and/or inhibition of targeted metabolic pathways in recipient lymph nodes will be assessed. Comprehensive analyses of HEV and CAP transcriptomes will open up new areas of investigation in vascular biology and immunology. Elucidation of the mechanisms of vascular control of lymphocyte recruitment may lead to novel targets and approaches for the control of autoimmune and other pathologic inflammation.