Phosphorothioate Oligonucleotides as Microbicides against HIV Transmission

描述（由申请人提供）：开发抑制艾滋病毒感染传播的干预措施对于遏制艾滋病毒流行至关重要。通常称为杀微生物剂的局部预防策略已被提议作为阻止或减缓HIV流行的一种策略。我们已经确定了新的铅杀微生物剂，有效地抑制艾滋病毒和SIV感染/复制体外。在我们之前的提交中，我们报道了具有硫代磷酸酯骨架（OPB）的寡核苷酸，其可以分别抑制人或猿PBMC中的HIVBaL或SIVmac 251感染和/或复制。OPB还抑制P4-R5 MAGI细胞被HIVBaL和HIVIIIB无细胞感染中的感染/复制。OPB连续暴露24 h后对PBMC或P4-R5 MAGI细胞无毒性。初步数据表明，OPB也可能抑制其他病毒，因为它对A型流感病毒也有效。因此，我们的第一代OPB可能是一种有效的抗HIV杀微生物剂，可在局部应用时预防粘膜部位的感染。我们的初步研究是用OPB的13 mer Poly T或Poly A寡核苷酸进行的，这表明该效应是序列独立的，甚至可能由硫代磷酸脱氧核糖糖骨架介导。事实上，在我们目前的重新提交中，我们提供了关于我们的下一代化合物的数据，这是一种无碱基的硫代磷酸2'脱氧核糖骨架（PDB），具有比OPB更有效的HIV抑制活性。我们在这里展示的14聚体PDB没有毒性，是HIV的有效抑制剂，并且具有作为抑制HIV诱导的IFN？产生的TLR 7/9拮抗剂的优势。后一种性质很重要，因为HIV感染的建立可能取决于TLR引发的HIV诱导的粘膜炎症。重要的是，我们表明PDB在pH 4.4的羟乙基纤维素（HEC）凝胶中配制时是有活性的，在pH过渡到中性pH时存活，并且在HEC中长时间保持其活性。我们假设PDB结合包膜病毒并通过充当“化学凝集素”来抑制其感染性。我们进一步假设PDB可以作为抗HIV的杀微生物剂，并且可以预防恒河猴的SIV阴道感染。R21阶段计划的研究将进一步优化和表征PDB的体外安全性和有效性及其在Swiss韦伯斯特小鼠阴道/宫颈刺激模型中的安全性。他们将确定最佳的大小和组成，仍然有效地对抗艾滋病毒，并表现出无毒性。最后，将研究PDB的作用机制，将测试PDB包合到羟乙基纤维素凝胶中的效果，并确定PDB对乳酸杆菌生长的影响。从R21阶段到R33阶段的进展设定了五个具体里程碑。R33阶段将测试PDB在预防阴道SIV感染方面的有效性，研究精浆和pH转变对OPB功效的影响，确定其对人类生殖器上皮组织的安全性，并研究其对HSV-2的有效性。目前的申请将允许广泛评估PDB作为可能的新型杀微生物剂候选物。这里提出的研究解决了开发抑制HIV感染传播的治疗方法的重要公共卫生问题。本申请研究了一种可用于抑制HIV感染的新型化学物质。

DESCRIPTION (provided by applicant): Developing interventions that inhibit the transmission of HIV infection are critical for halting the HIV epidemic. Topical prevention strategies usually termed microbicides have been proposed as one strategy to halt or slow down the HIV epidemic. We have identified novel lead microbicides that potently inhibit HIV and SIV infection/replication in vitro. During our previous submission we reported an oligonucleotide with a phosphorothioate backbone (OPB) that could inhibit HIVBaL or SIVmac251 infection and/or replication in human or simian PBMC, respectively. OPB also inhibited infection/replication in cell-free infections of P4-R5 MAGI cells by HIVBaL and HIVIIIB. OPB exhibited no toxicity against PBMC or P4-R5 MAGI cells after 24h continuous exposure. Preliminary data suggested that OPB may also inhibit other viruses as it was also effective against influenza type A virus. Thus, our first generation OPB may be a potent microbicide against HIV that prevents infection at mucosal sites when topically applied. Our preliminary studies were carried out with a 13mer Poly T or Poly A oligonucleotide of OPB and this suggested that the effect was sequence independent and may even be mediated by the phosphorothioate deoxyribose sugar backbone. Indeed in our current re-submission we present data on our next generation compound, a baseless phosphorothioate 2' deoxyribose backbone (PDB) that has more potent HIV inhibitory activity than OPB. A 14mer PDB we show here has no toxicity, is a potent inhibitor of HIV and has the advantage of being a TLR7/9 antagonist that inhibits HIV-induced IFN¿ production. This later property is important as the establishment of HIV infection may depend on HIV-induced mucosal inflammation triggered by TLR. Importantly, we show that PDB is active when formulated in hydroxyethylcellulose (HEC) gel at pH 4.4, survives pH transition to a neutral pH, and in retains its activity in HEC for long periods. We hypothesize that PDB binds enveloped viruses and inhibits their infectivity by acting as a "chemical lectin". We further hypothesize that PDB can act as a microbicide against HIV and can prevent SIV vaginal infection of rhesus macaques. The studies planned in the R21 phase will further optimize and characterize the safety and effectiveness of PDB in vitro and its safety in the Swiss Webster mouse vaginal/cervical model of irritation. They will determine the optimal size and composition that remains effective against HIV and exhibits no toxicity. Finally, the mechanism of action of PDB will be investigated, the effect of inclusion into hydroxyethylcellulose gel will be tested and PDB's effect on the growth of commensal lactobacilli will be determined. Five specific milestones have been set for the progression from the R21 Phase to the R33 Phase. The R33 phase will test the effectiveness of PDB in preventing vaginal SIV infection, investigate the effect of seminal plasma and pH transition on the efficacy of OPB, determine its safety with human genital epithelial tissue, and investigate its effectiveness against HSV-2. The current application will allow for an extensive evaluation of PDB as possible novel microbicide candidates. The studies proposed here address the important public health problem of developing treatments that inhibit the transmission of HIV infection. The current application investigates a novel chemical that may be used to inhibit infection with HIV.