Retrocyclins: circular defensins active against HIV-1

描述(申请人提供)：HIV-1在全世界最常见的传播途径是通过粘膜表面的性接触。尽管人们对艾滋病毒-1疫苗的开发给予了很大关注，但进展缓慢，迫切需要找到替代办法来控制艾滋病毒-1的传播。在寻找对HIV-1具有活性的新化合物的过程中，我们发现某些抗菌肽，即来自灵长类的阳离子theta-防御素，在体外可以有效地抑制HIV-1的感染。尽管人类不再产生theta-Defensin多肽，但人类骨髓以表达的假基因的形式提供了证据，证明这些多肽曾经是我们基因组遗产的一部分。利用其表达的假基因中仍然编码的序列信息，我们重新创建了这个丢失的人源多肽，我们将其命名为逆周期蛋白。我们确定，到目前为止，逆转录周期素和几个类似物抑制了到目前为止测试的几乎所有X4和R5初级分离株和实验室适应的HIV-1毒株的病毒进入。这种病毒抑制的性质是特殊的，因为对逆周期蛋白结构的轻微修改可以在抗HIV-1活性方面产生显著的变化。许多逆转录周期素基本上是无细胞毒性和非溶血性的，因此我们设计了具有高治疗指数的多肽类似物。根据我们的初步研究，我们假设：a)逆转录周期素类似物在人体体液中保持活性，诱导最小的病毒耐药性，表现出低的细胞和组织毒性，并是HIV-1传播的有效抑制剂，当局部应用于人宫颈阴道器官培养时，b)病毒诱导的干扰素-β是增强逆转录周期蛋白mRNA表达的重要因素，以及c)氨基糖苷类药物，可以抑制逆转录周期蛋白mRNA中的提前终止密码子，将使人类细胞能够表达功能性逆转录周期素肽。在一个多学科团队的帮助下，我们将通过以下方式验证这些假设：1)开发在阴道粘膜中显示出抗HIV-1效力的逆转录周期素类似物，同时将诱导病毒耐药性降至最低；2)表征逆周期蛋白表达的调节，并检测人类细胞产生功能性逆转录周期素的能力，以防止艾滋病毒-1感染。总体而言，这些研究是我们持续努力的自然延伸，我们正在努力将逆周期素定性和开发为局部药物，以防止艾滋病毒-1的粘膜传播。与公共卫生的相关性(Lay声明)：HIV-1最常见的传播途径是粘膜(如阴道)表面的性接触。我们已经发现了一种名为“逆转录周期蛋白”的新分子，它对HIV-1具有活性，并正在努力开发基于逆转录周期蛋白的药物，可以防止艾滋病毒-1的性传播。以乳膏或凝胶的形式提供这种制剂，将通过为脆弱的性伴侣提供一种看不见的有效保护手段来增强他们的能力。

DESCRIPTION (provided by applicant): The most common route of HIV-1 transmission throughout the world involves sexual contact at mucosal surfaces. Although much attention has been focused on vaccine development for HIV-1, progress has been slow and there is an urgent need to find alternative approaches to target the spread of HIV-1. In our search for novel compounds active against HIV-1 we discovered that certain antimicrobial peptides, the cationic theta-defensins from primates, could effectively inhibit HIV-1 infection in vitro. Although humans no longer produce theta-defensin peptides, human bone marrow provided the evidence - in the form of an expressed pseudogene - that these peptides were once part of our genomic heritage. Using the sequence information still encoded within its expressed pseudogene, we recreated this lost human peptide which we named retrocyclin. We determined that retrocyclin and several analogs inhibited viral entry of nearly all X4 and R5 primary isolates and lab-adapted strains of HIV-1 tested so far. The nature of the viral inhibition was specific, in that slight modifications to retrocyclin structure could impart significant variation in anti-HIV-1 activity. Many retrocyclins were essentially non-cytotoxic and non-hemolytic, and thus we have designed peptide analogs with high therapeutic indices. Based on our preliminary studies, we hypothesize that a) retrocyclin analogs will retain activity in human fluids, induce minimal viral resistance, exhibit low cyto- and histotoxicity, and be effective inhibitors of HIV-1 transmission when applied topically to human cervicovaginal organ culture, b) virally-induced IFN-beta is an essential factor that enhances the expression of retrocyclin mRNA, and c) agents such as aminoglycosides, which can suppress the premature termination codon in retrocyclin mRNA, will enable human cells to express functional retrocyclin peptides. With assistance from a multidisciplinary team, we will test these hypotheses by 1) developing retrocyclin analogs that exhibit anti- HIV-1 potency in the vaginal mucosa while minimally inducing viral resistance, and 2) characterizing the regulation of retrocyclin expression and examining the ability to human cells to produce functional retrocyclins that protect against HIV-1 infection. In the aggregate, these studies are natural extensions of our ongoing efforts to characterize and develop retrocyclins as topical agents that prevent mucosal transmission of HIV-1. RELEVANCE TO PUBLIC HEALTH (lay statement): HIV-1 is most commonly spread through sexual contact at mucosal (e.g. vaginal) surfaces. We have discovered a novel molecule called "retrocyclin" that is active against HIV-1, and are working to develop retrocyclin-based agents that can prevent sexual transmission of HIV-1. Availability of such agents, in the form of a cream or gel, would empower vulnerable sexual partners by providing them with an invisible, effective means of protection.