Targeted-delivery of small interference RNA against anthrax (1 R21 AI118228-01A1)

 描述：针对炭疽的小干扰RNA的靶向递送。炭疽病是一种严重的疾病，由一种能形成孢子的细菌引起。炭疽最常见于野生和家养哺乳动物物种;但也可能发生在人类，当他们暴露于受感染的动物或动物组织，或当炭疽孢子作为生物恐怖主义武器散布时。获得许可的疫苗BioThrax的复杂免疫时间表需要一种新的易于接种的炭疽疫苗。由于炭疽是一种很少在人类中自然发生的疾病，因此开发暴露后预防措施更为现实 或者用治疗代替大规模免疫接种，就像现在的疫苗一样。在接触后，巨噬细胞摄取炭疽孢子并移动到这些孢子发芽的淋巴结。B。炭疽菌随后被释放到血液中并产生毒素，这些毒素是疾病毒力的关键因素：保护性抗原（PA）、水肿因子（EF）和致死因子（LF）。PA是受体结合毒素组分，其附着于两种宿主细胞受体中的任一种：炭疽毒素受体1（ANTXR 1或肿瘤内皮标志物8/TEM 8）和炭疽毒素受体2（ANTXR 2或毛细血管形态发生蛋白2/CMG 2）。结合后，PA被切割，受体结合部分形成结合EF或LF的七聚体孔。毒素复合物被内吞并递送到胞质溶胶中。LeTx和EdTx的活性导致免疫系统功能障碍、水肿、休克和死亡。我们的初步研究表明，通过RNA干扰（RNAi）技术使用特异性抗ANTXR小干扰RNA（siRNA）抑制ANTXR的表达可以防止炭疽毒素的细胞毒性。我们假设，解毒的炭疽毒素可用作抗ANTXR siRNA的递送载体。为了评估这一假设，我们提出了以下三个具体目标：具体目标1：产生解毒的炭疽毒素用于靶向ANTXR的siRNA递送。具体目的2：评估ANTXR沉默细胞对炭疽毒素诱导的细胞毒性的抑制作用。具体目的3：评估抗ANTXR siRNA治疗在炭疽小鼠模型中的功效。 我们预计，提出的宿主靶向治疗策略将防止暴露于野生型甚至耐药B的患者的严重疾病和死亡。炭疽孢子自然感染或生物恐怖袭击。此外，该技术可以作为一个平台来开发，以治疗其他采用成孔毒素作为毒力因子的抗微生物剂耐药病原体。

 DESCRIPTION: Targeted-delivery of small interference RNA against anthrax. Anthrax is a serious disease caused by Bacillus afgfnthracis, a bacterium that forms spores. Anthrax most commonly occurs in wild and domestic mammalian species; but can also occur in humans when they are exposed to infected animals or animal tissues, or when anthrax spores are dispersed as a bioterrorist weapon. The complicated immunization schedule with the licensed vaccine BioThrax calls for a new and easily administered anthrax vaccine. Since anthrax is a disease that rarely occurs naturally in humans, it is more realistic to develop a post exposure prophylaxis or therapy instead of mass immunization, as with the current vaccine. Following exposure, macrophages ingest anthrax spores and travel to the lymph node where these spores germinate. The B. anthracis bacteria are then released into the bloodstream and produce toxins that are key factors in the virulence of disease: protective antigen (PA), edema factor (EF), and lethal factor (LF). PA is the receptor binding toxin component that attaches to either of two host cell receptors: anthrax toxin receptor 1 (ANTXR1 or tumor endothelial marker 8/TEM8) and anthrax toxin receptor 2 (ANTXR2 or capillary morphogenesis protein 2/CMG2). After binding, PA is cleaved and the receptor-bound portions form a heptameric pore that binds EF or LF. The toxin complexes are endocytosed and delivered into the cytosol. The activities of LeTx and EdTx result in malfunction of the immune system, edema, shock, and death. Our preliminary study has shown that inhibition of ANTXR expression by RNA interference (RNAi) technology using specific anti-ANTXR small interference RNA (siRNA) could prevent cytotoxicity of anthrax toxins. We hypothesize that a detoxified anthrax toxin could be used as a delivery vehicle for anti-ANTXR siRNA. In order to evaluate this hypothesis, we propose the following three specific aims: Specific Aim 1: To generate detoxified anthrax toxins for ANTXR-targeted siRNA delivery. Specific Aim 2: To assess the inhibitory effect on anthrax toxin induced cytotoxicity in ANTXR-silenced cells. Specific Aim 3: To evaluate efficacy of the anti-ANTXR siRNA treatment in a mouse model of anthrax. We anticipate that the proposed host-targeted treatment strategy will prevent severe illness and death in patients exposed to both wild type and even antibiotic-resistant B. anthracis spores by natural infection or a bioterrorist attack. Furthermore, this technology can be developed as a platform to treat other antimicrobial-resistant pathogens that employ pore-forming toxins as virulence factors.