A radiation-induced cellular stress activates HIV and induces killing of infected cells

HIV-1可以保存在长期静息的CD4+T细胞中，这些细胞在感染的患者中形成了一个病毒库 个人。即使患者通常接受治疗，这种蓄积物也可能持续很多年。 采用高效抗逆转录病毒疗法(HAART)，病毒种群一次即可恢复 HAART已停止。因此，对潜伏感染艾滋病毒的细胞的选择性激活导致 前病毒基因组的复制是免疫系统识别感染细胞的关键。我们的 长期目标是从潜伏和杀死受感染的细胞中找到重新激活HIV的方法 这不会杀死或摧毁未受感染的静止细胞，并随后瞄准并根除 持久的HIV-1蓄水池。我们有初步数据显示，一种典型的压力 信号，如辐射(IR)，激活感染艾滋病毒的T细胞不适当地进入S时相 感染细胞的细胞周期和病毒转录增加，并最终导致细胞凋亡。重要的是 亲代未受感染的细胞对相同的辐射剂量没有表现出这种反应。我们的 最近公布的数据阐明了这一现象，并表明(1)艾滋病毒-1的增加 IR诱导DNA损伤后通过表观遗传机制转录，证据为 RNA聚合酶II的存在及HDAC1和甲基转移酶SUV39H1的还原 HIV-1启动子；(2)细胞内HIV-1RNA水平升高和病毒表达增加 IR处理的HIV-1感染静止的CD4+T细胞中的蛋白质；(3)转录增强 PKC激动剂Bryostatin 1对潜伏感染HIV-1巨噬细胞IR后的激活作用 照射后HIV-1慢性感染细胞Ser46蛋白磷酸化水平升高致细胞死亡 P53，负责诱导细胞凋亡。最后，(5)将HIV-1感染暴露人性化 未检测到病毒RNA水平的小鼠对IR导致HIV-1 RNA显著增加 血浆和某些组织病毒库。我们假设，低IR引起的细胞应激 剂量重新激活潜伏感染细胞的HIV-1转录，导致核积聚 TAT，激活HIV-1基因组表达，促进感染但不是未感染的细胞凋亡， 细胞。我们的两个目标包括：a)确定HIV-1重新激活的机制 潜伏感染T细胞的治疗性X射线剂量及其对TAT激活的HIV-1的IR效应 转录；以及B)破译HIV-1感染细胞在 对红外线剂量的反应。这些拟议研究的预期结果包括澄清 决定HIV-1在潜伏感染细胞和组织中重新激活和凋亡的机制 对X射线红外光谱的反应。我们还希望确定不会破坏的最佳红外剂量 但可诱导潜伏感染细胞的HIV-1重新激活和凋亡。

HIV-1 can be preserved in the long-lived resting CD4+ T cells which form a viral reservoir in infected individuals. This reservoir may persist for many years even though the patients are usually treated with highly active antiretroviral therapy (HAART), and viral population can be recovered once HAART is stopped. Thus, the selective activation of the latently HIV-infected cells resulting in the replication of proviral genome is critical to make infected cells recognized by immune system. Our long term goal is to find the method of reactivation of HIV from latency and killing of infected cells that does not kill or destroy non-infected quiescent cells and subsequently target and eradicate the persistent HIV-1 reservoirs. We have preliminary data showing that a well-characterized stress signal, such as irradiation (IR), activated inappropriate entry of the HIV infected T cells to S phase of the cell cycle and increased viral transcription and eventual apoptosis of infected cells. Importantly, the parental uninfected cells did not demonstrate this response to the same irradiation dose. Our recently published data elucidated this phenomenon and indicated (1) increase of HIV-1 transcription via epigenetic mechanisms after the IR-induced DNA damage, as evidenced by the presence of RNA polymerase II and reduction of HDAC1 and methyl transferase SUV39H1 on the HIV-1 promoter; (2) elevated level of intracellular HIV-1 RNA and increased expression of viral proteins in the IR-treated HIV-1 infected quiescent CD4+ T cells; (3) enhancement of transcription activation in latently HIV-1infected macrophages treated with PKC agonist bryostatin 1 after IR; (4) higher death of irradiated HIV-1 chronically-infected cells via increased phosphorylation of Ser46 in p53 that is responsible for apoptosis induction. Finally, (5) exposure of HIV-1 infected humanized mice with undetectable viral RNA level to IR resulted in a significant increase of HIV-1 RNA in plasma and certain tissue viral reservoirs. We hypothesize, that the cellular stress induced by low IR doses reactivates HIV-1 transcription from latently infected cells resulting in nuclear accumulation of Tat, activation of HIV-1 genome expression and enhanced apoptosis of infected, but not uninfected, cells. Our two aims include; A) To identify the mechanism of HIV-1 reactivation in response to therapeutic X-ray doses in latently infected T cells and to assess IR effect on the Tat activated HIV-1 transcription; and B) To decipher mechanism of enhanced apoptosis of HIV-1 infected cells in response to IR doses. The expected outcomes of these proposed studies include elucidation of the mechanisms that determine HIV-1 reactivation and apoptosis in latently infected cells and tissues in response to the X ray IR. We also expect to determine optimal IR dose that does not destroy uninfected cells, but induces HIV-1 reactivation and apoptosis of latently infected cells.