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

HIV-1可以保存在长寿命的静息CD4 + T细胞中，这些T细胞在感染者中形成病毒库。 个体即使患者通常接受治疗，这种储库也可能持续多年 高效抗逆转录病毒治疗（HAART），病毒种群可一次性恢复 HAART停止了。因此，潜伏HIV感染细胞的选择性激活导致了HIV感染的发生。 前病毒基因组的复制是使感染细胞被免疫系统识别的关键。我们 长期目标是找到从潜伏期和杀死感染细胞中重新激活HIV的方法 不杀死或破坏未感染的静止细胞，随后靶向并根除 持续的HIV-1储存库。我们有初步的数据表明，一个很好的特点压力， 信号，如辐射（IR），激活HIV感染的T细胞不适当地进入S期， 细胞周期和增加的病毒转录和最终的受感染细胞的凋亡。重要的是， 未感染的亲本细胞对相同的辐射剂量没有表现出这种反应。我们 最近发表的数据阐明了这一现象，并表明（1）HIV-1的增加 转录通过表观遗传机制后，IR诱导的DNA损伤，证明了这一点， RNA聚合酶II的存在以及HDAC 1和甲基转移酶SUV 39 H1在细胞表面的减少， HIV-1启动子;（2）细胞内HIV-1 RNA水平升高和病毒表达增加 IR处理的HIV-1感染的静止期CD4 + T细胞中的蛋白质;（3）转录增强 IR后PKC激动剂苔藓抑素1处理的潜伏性HIV-1感染的巨噬细胞中的活化;（4） 通过增加Ser46的磷酸化， p53负责细胞凋亡诱导。最后，（5）暴露HIV-1感染的人源化 病毒RNA水平检测不到的小鼠IR导致HIV-1 RNA的显著增加， 血浆和某些组织病毒库。我们推测，低IR诱导的细胞应激 剂量重新激活潜伏感染细胞的HIV-1转录，导致细胞核积聚 达特，HIV-1基因组表达的激活和感染者的细胞凋亡的增强，但未感染者的细胞凋亡没有增强， 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X射线剂量，并评估IR对达特活化HIV-1的作用 B）为了解释HIV-1感染的细胞的凋亡增强的机制， 对IR剂量的反应。这些拟议研究的预期成果包括阐明 HIV-1在潜伏感染的细胞和组织中的再活化和凋亡的机制， 我们还希望确定不破坏X射线IR的最佳IR剂量， 未感染的细胞，但诱导HIV-1再活化和潜在感染细胞的凋亡。

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.