DC-SIGN Inhibitors for the Treatment of HIV Infection

DC-SIGN（树突状细胞特异性icam -3非整合素）是c型凝集素家族的一种膜蛋白，在单核细胞来源的dc、一些巨噬细胞和活化的B细胞中含量较高。在体内，DC-SIGN阳性细胞出现在淋巴结、扁桃体、皮肤和宫颈上皮下区域。DC- SIGN已被证明与许多病毒、分枝杆菌和原生动物寄生虫利什曼原虫结合。具体来说，DC-SIGN已被确定为人类免疫缺陷病毒（HIV-1和HIV-2）、猴免疫缺陷病毒（SIV）、登革热病毒、马尔堡病毒、丙型肝炎、埃博拉病毒和巨细胞病毒的树突状细胞受体。关于HIV-1的传播，DC-SIGN已被证明是有效结合、浓缩和介导病毒从粘膜表面转移到CD4+ T细胞的配体。表达DC-SIGN的上皮下dc已被证明在HIV-1的宫颈阴道传播中发挥重要作用。沿着这条路线，其他几项研究已经检查了dc - sign介导的各种病原体传播过程，并表明靶向这种细胞表面分子可能作为潜在的治疗策略。DC-SIGN结合高甘露糖，并以高亲和力聚焦存在于HIV包膜糖蛋白gp120上的部分。在原发感染部位阻断这种相互作用可能是潜在的预防和/或有效的杀微生物靶点。RNA干扰和碳水化合物结合剂已被证明是抑制dc - sign介导的HIV-1传播的潜在手段。RNA-based疗法;然而，目前在给药、稳定性和效力方面存在障碍。同样，将碳水化合物转化为有效的抑制剂可能具有挑战性。最近有报道称，HTS小分子文库筛选产生了微摩尔到亚微摩尔的非碳水化合物命中，以阻断DC-SIGN和GP120的相互作用。这证实了非碳水化合物库的HTS可以产生微摩尔的非碳水化合物命中。为了最大限度地提高成功的机会，我们将从三个来源寻找非碳水化合物：内部库的HTS，锌数据库的虚拟筛选和“结合位点定向亲脂性挖掘”方法。本课题的具体目标是：1)发现具有微摩尔结合活性的非碳水化合物小分子，阻断DC-SIGN与GP120的相互作用；2) Aim 1的命中将被聚集并优先分为3个化学型，这些化学型将通过检查合成或从商业来源获得的结构变体的活性来进行研究和验证。在第一阶段结束时，我们将确定至少一种先进的类似药物的非碳水化合物结构，可以阻断gp120与DC-SIGN的结合，以关键的代表性成员为例，这些成员对第二阶段的整个研究项目有足够的兴趣。

DESCRIPTION (provided by applicant): DC-SIGN (dendritic cell specific ICAM-3-grabbing non-integrin), a membrane protein of C-type lectin family, is found in high levels on monocyte-derived DCs, some macrophages, and activated B cells. In vivo, DC-SIGN- positive cells were demonstrated in lymph nodes, tonsils, skin, and the subepithelial region of the cervix. DC- SIGN has been shown to bind to a number of viruses, mycobacteria, and the protozoan parasite Leishmania. Specifically, DC-SIGN has been identified as the dendritic cell receptor for human immunodeficiency virus (HIV-1 and HIV-2), simian immunodeficiency virus (SIV), dengue virus, Marburg virus, hepatitis C, Ebola, and cytomegalovirus. With respect to HIV-1 transmission, DC-SIGN has been shown to serve as ligand that efficiently binds, concentrates, and mediates transfer of virus from the mucosal surface to CD4+ T cells. Subepithelial DCs expressing DC-SIGN have been demonstrated to play important roles in cervicovaginal transmission of HIV-1. Along this line, several other studies have examined the process of DC-SIGN-mediated transmission of various pathogens and have suggested that targeting this cell surface molecule may serve as potential therapeutic strategy. DC-SIGN binds to high mannose and fucose moieties present on the HIV envelope glycoprotein gp120 with high affinity. Blocking this interaction at the site of primary infection could potentially be prophylactic and/or a potent microbicidal target. Both RNA interference and carbohydrate-binding agents have been shown as potential means to inhibit DC-SIGN-mediated transmission of HIV-1. RNA-based therapies; however, present obstacles with respect to delivery, stability and potency. Similarly, converting carbohydrate leads to effective inhibitors could be challenging. Recently HTS screening of small molecule library has been reported to produce micromolar to sub-micromolar noncarbohyrate hits to block DC-SIGN and GP120 interaction. This validated the notion that HTS of noncarbohyrate library can produce micromolar noncarbohydrate hits. To maximize the chance of success, we will look for non-carbohydrate hits from three sources: HTS of in-house library, virtual screening of Zinc database, and "binding-site directed lipophilic mining" approach. The Specific Aims of this proposal are to 1) Discover a non-carbohydrate small molecule hit with micromolar binding activity to block the interaction of DC-SIGN and GP120; and 2) The hits from Aim 1 will be clustered and prioritized into ~3 chemotypes which will be investigated and validated by examining the activity of structural variants prepared by synthesis or acquired from commercial sources. At the end of Phase 1, we will have identified at least one advanced drug- like hit with noncarbohydrate structure that blocks gp120 binding to DC-SIGN, exemplified by key representative members that are of sufficient interest for a full program of study in Phase 2.