CXCR4: A potential therapeutic target in HSK

在美国，疱疹间质角膜炎(HSK)是感染导致视力丧失的主要原因。HSK考试 对角膜单纯疱疹病毒-1(HSV-1)感染有反应。复发性角膜HSV-1感染 可导致先天免疫细胞，如单核细胞、中性粒细胞和效应器CD4T细胞在 感染的角膜的角膜基质。由于中性粒细胞和效应性CD4T细胞在 HSK角膜在协调组织损伤、操纵滞留的策略方面发挥着关键作用 HSK角膜中免疫细胞的渗入有望起到减轻HSK严重程度的作用。 趋化因子受体，如CXCR4，在炎症细胞滞留中发挥重要作用。 受伤的组织。CXCR4信号也被报道促进缺血组织的血管生成。我们的预赛 结果表明，在HSV-1感染的角膜中，CXCR4和CXCL12的表达增加。我们最近 将完整的角膜上皮(CE)和角膜基质(CS)与未感染的角膜上皮(CE)和基质(CS)分离的标准化方案 和HSV-1感染的角膜。由单个CE和CS制备的单细胞悬浮液可用于流动 细胞学。使用这一策略，我们检测到在未感染的CE中存在CXCR4表达的细胞。 C57BL/6小鼠。我们的结果表明，在幼稚角膜的CE中，大多数表达CXCR4的细胞都显示出 朗格汉斯细胞(LCS)或浆细胞样树突状细胞(PDCs)的表型。最近，单胺类药物已经被 显示与PDCs上的CXCR4结合，并抑制干扰素-α的产生。组胺是一种释放的单胺 在角膜HSV-1感染时。目标1中提出的实验将检验组胺在体内释放的假设 HSV-1感染的角膜与pDC上的CXCR4结合，并抑制CE pDC产生干扰素-a，增加 病毒载量。我们的结果还表明，在CE中，LC的数量减少，而在CS中，LC的数量从4个增加到5个。 感染后1天至9天(P.I.)，提示这些细胞可能在感染HSV-1后从CE迁移到CS 眼角膜。CXCL12(CXCR4配体)在CS中的表达高于感染角膜的CE中的表达 在9天的P.I.此外，感染角膜CS中的大多数CD4T细胞表现为效应型(Ly6chi) 在9天的P.I.目标1中提出的实验将检验LCS介导的效应器重新刺激的假设 感染角膜CS中的CD4T细胞对它们的滞留和效应功能是必不可少的。目标1 实验还将测试LCS是否迁移出CE和中性粒细胞是否渗入HSV-1感染的CE中 角膜损害角膜上皮的愈合。除了角膜固有免疫细胞外，我们的结果还 CXCR4在新生中性粒细胞和血管内皮细胞上的表达 HSK角膜CS的血管分布。目标2中提出的实验将检验阻断的假设 CXCR4在HSK角膜中的信号转导将导致中性粒细胞的反向迁移，从而抑制青光眼的发展 血管生成。成功完成本申请书中建议的研究将突出 CXCR4信号在HSK角膜中的多效性作用，并将其作为HSK潜在的治疗靶点。

Herpes stromal keratitis (HSK) is a leading cause of infection-induced vision loss in the United States. The HSK develops in response to corneal herpes simplex virus-1 (HSV-1) infection. Recurrent corneal HSV-1 infection can cause the persistence of innate immune cells, such as monocytes, neutrophils, and effector CD4 T cells in the corneal stroma of the infected cornea. As the accumulation of neutrophils and effector CD4 T cells in the HSK cornea plays a pivotal role in orchestrating the tissue damage, the strategies to manipulate the stay of infiltrating immune cells in the HSK cornea are anticipated to have an effect in reducing the HSK severity. Chemokine receptors, such as CXCR4, can play an important role in the retention of inflammatory cells in the injured tissue. CXCR4 signaling is also reported to enhance hemangiogenesis in ischemic tissue. Our preliminary results showed an increased expression of CXCR4 and CXCL12 in HSV-1 infected cornea. We recently standardized a protocol to separate an intact corneal epithelium (CE) and corneal stroma (CS) from uninfected and HSV-1 infected cornea. Single-cell suspension prepared from individual CE and CS can be used for flow cytometry. Using this strategy, we detected the presence of CXCR4-expressing cells in uninfected CE of C57BL/6 mice. Our results showed that most CXCR4-expressing cells in CE of naïve cornea display the phenotype of Langerhans cells (LCs) or plasmacytoid dendritic cells (pDCs). Recently, monoamines have been shown to engage CXCR4 on pDCs and inhibit IFN-a production. Histamine is a monoamine that is released upon corneal HSV-1 infection. Experiments proposed in aim 1 will test the hypothesis that histamine released in HSV-1 infected cornea engages CXCR4 on pDCs, and downplays IFN-a production from CE pDCs, increasing viral load. Our results also showed that the number of LCs decreases in the CE but increases in the CS from 4- day to 9-day post-infection (p.i.), suggesting a possible migration of these cells from CE to CS in HSV-1 infected corneas. An increased expression of CXCL12 (CXCR4 ligand) was detected in CS than CE of the infected cornea at 9-day p.i. Furthermore, most CD4+ T cells in the CS of infected cornea displayed effector (Ly6Chi) phenotype at 9-day p.i. Experiments proposed in aim 1 will test the hypothesis that LCs-mediated restimulation of effector CD4 T cells in the CS of the infected cornea is essential for their retention and effector function. Aim 1 experiments will also test whether LCs migrating out of CE and neutrophils infiltrating in the CE of HSV-1 infected cornea impair corneal epithelial healing. In addition to corneal resident innate immune cells, our results also detected the expression of CXCR4 on infiltrated neutrophils and vascular endothelial cells from newly formed blood vessels in the CS of HSK cornea. Experiments proposed in aim 2 will test the hypotheses that blocking CXCR4 signaling in HSK cornea will cause reverse migration of neutrophils and inhibit the development of hemangiogenesis. The successful completion of the studies proposed in this application will underscore the pleiotropic effects of CXCR4 signaling in HSK cornea and document it as a potential therapeutic target in HSK.