Ciprofloxacin enhances DNA repair capacity after radiation combined injury

描述（由申请人提供）：本申请解决了放射性复合损伤（CI）医学治疗的一个主要空白。氟喹诺酮类药物，如环丙沙星（CIP），通常耐受性良好，常用于治疗一般人群的感染。美国食品和药物管理局（FDA）建议使用CIP治疗炭疽，并将其保存在国家储备库中，供国家紧急情况下特定人类使用。我们假设CIP通过遗传毒性应激反应间接或直接通过修饰染色质和/或抑制真核拓扑异构酶（topo）II的能力发挥辐射防护/治疗作用。CIP通过抑制细菌DNA旋转酶（细菌topo II或topo IV）起作用，但对真核topo II具有轻微的抑制作用。Topo II催化双链DNA断裂/再连接反应。我们的理由是基于：1）小鼠研究，其中CIP提高了9.75戈伊全身照射（TBI）和CI小鼠后的存活率，和2）与TBI相比，CIP提高了接受6.5戈伊TBI的恒河猴的DNA修复能力。我们的长期目标是（1）阐明与联合损伤（CI-辐射加皮肤伤口创伤）相关的病理机制，（2）评估选定的抗菌药物治疗CI后脓毒症的疗效。我们的短期目标是1）阐明与TBI-CIP动物明显增强的基因组稳定性相关的分子机制，2）阐明B6 D2 F1雌性小鼠辐射损伤（RI）和CI后存活率增加的分子途径。我们将在三个具体目标中实现这些目标：目标1。评估CIP在人淋巴母细胞TK 6细胞中的生物活性和血液离体药效学试验，目的2。通过（a）定量CI后造血组织、伤口组织中细胞周期、DNA修复和凋亡的同源基因和蛋白质，和（B）通过FACS评估DNA损伤/修复和凋亡标志物，在体内测量小鼠中的CIP分子药效学，和Aim 3。通过离体基因组激发测定区分RI和CI的造血样品中CI和CIP后基因组稳定性的变化。R33部分将分为3个定义的任务：（a）辐射防护/治疗有效性（B）作用机制和（c）基因组/蛋白质组学分析。对免疫调节特性和检查点通路激活的更多理解将促进CIP的更大效用，以及喹诺酮类抗菌剂如何赋予基因组稳定性，增强伤口愈合和提高生存率。环丙沙星（CIP）是国家战略储备，用于炭疽治疗的紧急用途，CIP配方，安全性和制造要求已经满足美国食品和药物管理局的人类使用。除了抗微生物活性外，对非人类灵长类动物的初步研究表明，CIP可以增加固定DNA的能力并诱导免疫系统，这些作用很可能是有益的，可以减少未来的癌症死亡。在核事件的情况下，例如脏弹或核事故，成千上万的人可能暴露于辐射复合损伤，CIP可以提供一种具有成本效益的治疗方法，可以显着提高生存机会作为抗微生物剂，增强成熟血细胞的产生和伤口愈合，从而在医疗设施不堪重负时减少住院的必要性。

DESCRIPTION (provided by applicant): This application addresses a major gap for medical treatment of radiation combined injuries (CI). Fluoroquinolones, like ciprofloxacin (CIP), are generally well-tolerated and commonly used for treating infections in the general population. The Food and Drug Administration (FDA) has recommended CIP for anthrax treatment, and it is maintained in the National Stockpile for specific human use in the event of a national emergency. We hypothesize that CIP exerts a radioprotective/therapeutic effect either indirectly through genotoxic stress response, or directly via ability to modify chromatin and/or inhibit eukaryotic topoisomerase (topo) II. CIP works by inhibiting bacterial DNA gyrase (bacterial topo II or topo IV), but has a slight inhibitory effects on eukaryotic topo II. Topo II catalyzes the double strand DNA break/religation reaction. Our rationale is based on: 1) mouse studies where CIP enhanced survival after 9.75 Gy total body irradiation (TBI) and CI mice and 2) increased DNA repair capacity in rhesus macaques that received 6.5 Gy TBI with CIP compared to TBI. Our long-term goals are to (1) clarify the pathologic mechanisms associated with combined injury (CI-radiation plus skin-wound trauma) and (2) assess the efficacy of selected antimicrobials for treating sepsis after CI. Our short-term goals are to 1) clarify the molecular mechanisms associated with apparent enhanced genomic stability conferred on TBI-CIP animals, and 2) to elucidate molecular pathways involved in increased survival after radiation injury (RI) and CI in B6D2F1 female mice. We will address these goals in three Specific Aims: Aim 1. Assess biological activities of CIP in human lymphoblastoid TK6 cells and a blood ex vivo pharmacodynamic assay, Aim 2. Measure CIP-molecular pharmacodynamics in mice in vivo by (a) quantify homologous genes and proteins for cell cycle, DNA repair, and apoptosis in hematopoietic, wound tissues following CI, and (b) assess DNA damage/ repair and apoptotic markers by FACS, and Aim 3. Discriminate changes in genomic stability post CI and CIP in hematopoietic samples for RI and CI by genomic challenge assay ex vivo. The R33 portion will be divided into 3 defined tasks: (a) radioprotective/therapeutic efficacy (b) mechanisms of action, and (c) genomic/proteonomic profiling. The increased understanding of immunomodulatory properties and activation of checkpoint pathways will facilitate greater utility of CIP, and of how quinolone antimicrobials might confer genomic stability, enhance wound healing, and improve survival. Ciprofloxacin (CIP) is in the Strategic National Stockpile for emergency use for anthrax treatment, and CIP formulation, safety, and manufacturing requirements are already fulfilled for human use by the Food and Drug Administration. In addition to antimicrobial activity, preliminary studies in non-human primates show that CIP increases the ability to fix DNA and induces the immune system, and these effects are, in all probability, beneficial as a bonus that might reduce future cancer deaths. In a scenario of a nuclear event, such as a dirty bomb or nuclear accident, where tens of thousands of people are potentially exposed to radiation-combined injuries, CIP may offer a cost-effective treatment that could significantly improve the chance of survival as anti-microbial agents that enhance production of mature blood cells and wound healing, thereby reducing the necessity of hospitalization at a time when medical facilities would be overwhelmed.