Impact of μ-opioid receptor (MOR) splice variant interactions with the chemokine receptor CCR5 in the context of morphine and HIV-1 entry inhibitor therapy

 描述(申请人提供)：越来越多的证据表明，阿片类药物滥用加剧了神经艾滋病，这些影响主要是通过μ-阿片受体(MOR)介导的。也有证据表明，MOR-1可能在HIV-1(HIV-1)复制和发病机制中起直接作用。MOR不是一个单一的实体，而是以多种功能不同的异构体存在。尽管存在重大的根本差异，但大多数研究MOR的研究都集中在典型的MOR-1上，在阿片类药物与艾滋病毒相互作用的研究中尤其如此。虽然MOR-1-HIV-1相互作用已被广泛研究，但HIV对MOR剪接变体调控以及反过来MOR变体对HIV细胞结合和进入的调控作用仍是一个未被探索的领域。因此，鉴于MOR-1被认为通过异源二聚化和/或下游信号转导与HIV共受体如CCR5相互作用，本赠款的目标是在吗啡和HIV-1进入抑制剂马拉韦罗的背景下，解决与CCR5在中枢神经系统中介导HIV相关过程有关的MOR的变化。初步研究发现：(I)MOR-1可能不是所有类型CNS细胞上的主要MOR形式，(Ii)N端突变体MOR-1K在细胞信号转导方面与MOR-1不同(Iii)尽管星形胶质细胞和小胶质细胞都含有多种MOR变体，但星形胶质细胞中MOR-CCR5相互作用最多。(Iv)MOR-CCR5相互作用在小胶质细胞和星形胶质细胞中发生得更多，(Iv)MOR的主要激动剂吗啡能够以MOR依赖的方式在星形胶质细胞和小胶质细胞中消除CCR5介导的病毒进入抑制剂马拉韦罗的抗病毒作用。本提案旨在1.(1)确定与胶质细胞(星形胶质细胞和小胶质细胞)中的趋化因子和HIV(共)受体CCR5相互作用的MOR剪接变异体，以及(2)在针对CCR5介导的进入的临床相关病毒进入抑制剂马拉韦罗的背景下，确定这些相互作用如何影响阿片类药物的病毒进入。该项目的研究结果可以通过针对特定的MOR变异体进一步确定阿片类药物滥用者艾滋病毒相关并发症进展的机制，以及特定细胞类型是否正在调节中枢神经系统对这些并发症的易感性。这些发现还可能扩展到进一步开发针对这种相互作用的艾滋病毒进入抑制剂。

 DESCRIPTION (provided by applicant): Growing evidence suggests that opioid abuse exacerbates neuroAIDS and these effects are mainly mediated through the μ-opioid receptor (MOR). There is also evidence to suggest that MOR-1 may have a direct role in HIV type-1 (HIV-1) replication and pathogenesis. MOR is not a single entity, but instead exists as multiple isoforms that differs in function. Despite significant fundamental differences, most studies examining MOR have focused on the canonical MOR-1, and this is particularly true in studies of opioid drug-HIV interactions. Although MOR-1- HIV-1interactions have been studied extensively, the role of MOR splice variant regulation by HIV and, conversely, MOR variant regulation of HIV cellular binding and entry is an unexplored area. Therefore, given that MOR-1 is thought to interact with HIV co-receptors such as CCR5 via heterodimerization and/or downstream signaling, the goal of this grant is to address the variation of MOR in relation to CCR5 mediation of HIV-associated processes in the CNS in the context of morphine and the HIV-1 entry inhibitor maraviroc. Preliminary studies found that: (i) MOR-1 may not be the predominate form of MOR on all CNS cell types, (ii) the N-terminal variant MOR-1K differs functionally in cellular signaling compared to MOR-1 (iii) although both astrocytes and microglia harbors multiple MOR variants, astrocytes harbors the most (iv) MOR-CCR5 interaction occurs in both microglia and astrocytes, although more so in astrocytes and (iv) morphine the predominant agonist of MOR was able to abolish the antiviral effect of the CCR5-mediated viral entry inhibitor maraviroc in a MOR-dependent manner in both astrocytes and microglia. The present proposal is designed to 1. (i) identify the MOR splice variants that interact with the chemokine and HIV (co-) receptor CCR5 in glia (astroglia and microglia) and (ii) determine how these interactions affect viral entry in opioid using individuals in the context of the clinically relevant viral entry inhibitor maraviroc which targets CCR5-mediated entry. The findings from this project could further define the mechanisms in the progression of HIV-related complications in opioid abusers by targeting specific MOR variants and whether a particular cell type is modulating the vulnerability to these complications in the CNS. These findings may also extend to further develop HIV entry inhibitors targeting this interaction.