Ciprofloxacin enhances DNA repair capacity after radiation combined injury

描述（由申请人提供）：本申请解决了辐射复合损伤（CI）医学治疗的主要空白。氟喹诺酮类药物，如环丙沙星（CIP），通常耐受性良好，通常用于治疗普通人群的感染。美国食品和药物管理局（FDA）建议将CIP用于炭疽治疗，并将其保存在国家储备中，供国家紧急情况下的特定人类使用。我们假设CIP通过基因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的能力发挥放射保护/治疗作用。CIP通过抑制细菌的DNA回转酶（细菌topo II或topo IV）起作用，但对真核生物的topo II有轻微的抑制作用。Topo II催化双链DNA断裂/宗教反应。我们的基本原理是基于：1)小鼠研究，在9.75 Gy全身照射（TBI）和CI小鼠后，CIP提高了存活；2)与TBI相比，接受6.5 Gy TBI的恒河猴的DNA修复能力增加。我们的长期目标是：(1)阐明与复合损伤（CI辐射加皮肤伤口创伤）相关的病理机制；(2)评估所选抗菌药物治疗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)阐明与B6D2F1雌性小鼠辐射损伤（RI）和CI后生存率增加有关的分子途径。我们将通过三个具体目标来实现这些目标：目标1。评估CIP在人淋巴母细胞样TK6细胞中的生物活性和血液离体药效学测定，目的2。通过(a)量化造血、创面组织中细胞周期、DNA修复和凋亡的同源基因和蛋白，以及(b)通过FACS和Aim 3评估DNA损伤/修复和凋亡标志物，在小鼠体内测量cip分子药效学。通过体外基因组挑战测定，区分造血样本在CI和CI后基因组稳定性的变化。R33部分将分为3个明确的任务：(a)放射防护/治疗功效(b)作用机制，以及(c)基因组/蛋白质组学分析。对免疫调节特性和检查点途径激活的进一步了解将促进CIP的更大应用，以及喹诺酮类抗菌剂如何赋予基因组稳定性、促进伤口愈合和提高生存率。环丙沙星（CIP）被列入国家战略储备，用于紧急治疗炭疽，并且CIP的配方、安全性和制造要求已经由美国食品和药物管理局满足。除了抗菌活性外，对非人类灵长类动物的初步研究表明，CIP增加了修复DNA和诱导免疫系统的能力，这些效果很可能是有益的，可能会减少未来的癌症死亡。在核事件的情况下，如脏弹或核事故，成千上万的人可能受到辐射联合伤害，CIP可能提供一种具有成本效益的治疗方法，可以显著提高生存机会，作为抗微生物剂，促进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.