Effects of Antiretroviral Therapy on Telomerase Function in Human Oral Epithelium

描述(申请人提供)：该项目的长期目标是减少或逆转感染人类免疫缺陷病毒(HIV)患者接受高效抗逆转录病毒疗法(HAART)的口腔并发症。虽然引入HAART后HIV感染的口腔表现显著减少，但也有一些不良反应在口腔粘膜中被报道，包括复发性口腔溃疡、上皮萎缩、多形性红斑、上皮脱屑、发作性毛囊炎和多发性口腔疣。目前应用的目的是阐明逆转录酶抑制物(RTI)抑制端粒酶在介导HAART副作用中的作用。端粒酶是一种细胞逆转录酶，至少具有两种不同的生物学功能：(1)合成端粒DNA；(2)维持基因组的完整性。本实验室在口腔上皮来源的正常口腔角质形成细胞(NHOK)中发现端粒酶活性显著升高。NHOK中的端粒酶活性与活跃的细胞增殖有关，在细胞衰老过程中完全丧失。重要的是，端粒酶活性可以被几种通常用作HAART的RTI有效地抑制。这一建议的中心假设是，RTI对NHOK中端粒酶的抑制是导致HIV+患者长期使用HAART导致口腔上皮再生能力减弱和不良口腔粘膜并发症的原因。为了验证我们的假设，我们提出了三个具体的目标：(1)确定体外RTI暴露于NHOK以及有或没有HAART的HIV+患者来源的细胞中的端粒酶活性、端粒状态和细胞表型变化；(2)确定RTI/HAART对NHOK细胞DNA修复活性、突变频率和遗传完整性的影响；以及(3)研究AZT对NHOK表达外源性端粒酶或获得增强的复制潜力的表型变化的影响。目标1和2将研究口腔上皮中RTI/HAART的详细表型和遗传效应。在目标3中，我们将确定增强细胞端粒酶活性和/或使细胞具有增强的复制能力是否可以防止AZT的不利表型效应。该项目的成果将用于预防和管理艾滋病毒感染和获得性免疫缺陷综合征(艾滋病)的口腔表现，减少HAART的负面影响。

DESCRIPTION (provided by applicant): The long-term goal of this project is to reduce or reverse the oral complications of highly active antiretroviral therapy (HAART) in patients infected with the human immunodeficiency virus (HIV). Although the oral manifestations of HIV infection have significantly decreased after the introduction of HAART, several adverse effects have also been reported in the oral mucosa, including recurrent oral ulceration, epithelial atrophy, erythema multiforme, epithelial desquamation, eruptive chielitis, and multiple oral warts. The purpose of the current application is to elucidate the effects of telomerase inhibition by reverse transcriptase inhibitors (RTIs) in mediating the side effects of HAART. Telomerase is a cellular reverse transcriptase with at least two distinct biological functions in (1) synthesis of telomere DNA and (2) maintenance of genome integrity. Our laboratory found remarkably high level of telomerase activity in normal human oral keratinocytes (NHOK) derived from oral epithelium. Telomerase activity in NHOK is specifically associated with actively proliferating cells and is completely lost during cellular senescence. Importantly, telomerase activity can be effectively inhibited by several RTIs commonly used as HAART. The central hypothesis of this proposal is that telomerase inhibition in NHOK by RTIs is responsible for the diminution of regenerative capacity of the oral epithelium and adverse oral mucosal complications associated with long-term administration of HAART in HIV+ patients. To test our hypothesis, we propose three Specific Aims: (1) to determine the telomerase activity, telomeric status, and cellular phenotypic alterations in NHOK exposed to RTIs in vitro and in cells derived from HIV+ patients with and without HAART; (2) to determine the effects of RTI/HAART on the DNA repair activities, mutation frequency, and genetic integrity in NHOK; and (3) to investigate the effects of AZT on phenotypic alterations in NHOK expressing exogenous telomerase or acquiring enhanced replication potential. The aims 1 and 2 will investigate the detailed phenotypic and genetic effects of RTI/HAART in oral epithelium. In aim 3, we will determine whether augmenting cellular telomerase activity and/or "priming" the cells with enhanced replicative potential can prevent the adverse phenotypic effects of AZT. The outcome of this project will be used for prevention and management of oral manifestations of HIV infection and the acquired immunodeficiency syndrome (AIDS) by reducing the negative effects of HAART.