Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
PLoS Biol. 2020 May 26;18(5):e3000660. doi: 10.1371/journal.pbio.3000660. eCollection 2020 May.
Increased life expectancy of patients diagnosed with HIV in the current era of antiretroviral therapy is unfortunately accompanied with the prevalence of HIV-associated neurocognitive disorders (HANDs) and risk of comorbidities such as Alzheimer-like pathology. HIV-1 transactivator of transcription (Tat) protein has been shown to induce the production of toxic neuronal amyloid protein and also enhance neurotoxicity. The contribution of astrocytes in Tat-mediated amyloidosis remains an enigma. We report here, in simian immunodeficiency virus (SIV)+ rhesus macaques and patients diagnosed with HIV, brain region-specific up-regulation of amyloid precursor protein (APP) and Aβ (40 and 42) in astrocytes. In addition, we find increased expression of β-site cleaving enzyme (BACE1), APP, and Aβ in human primary astrocytes (HPAs) exposed to Tat. Mechanisms involved up-regulation of hypoxia-inducible factor (HIF-1α), its translocation and binding to the long noncoding RNA (lncRNA) BACE1-antisense transcript (BACE1-AS), resulting, in turn, in the formation of the BACE1-AS/BACE1 RNA complex, subsequently leading to increased BACE1 protein, and activity and generation of Aβ-42. Gene silencing approaches confirmed the regulatory role of HIF-1α in BACE1-AS/BACE1 in Tat-mediated amyloidosis. This is the first report implicating the role of the HIF-1α/lncRNABACE1-AS/BACE1 axis in Tat-mediated induction of astrocytic amyloidosis, which could be targeted as adjunctive therapies for HAND-associated Alzheimer-like comorbidity.
在当前抗逆转录病毒治疗时代,诊断出 HIV 的患者的预期寿命有所延长,但不幸的是,随之而来的是 HIV 相关神经认知障碍 (HANDs) 的流行以及合并症(如阿尔茨海默病样病理)的风险。HIV-1 转录激活物 (Tat) 蛋白已被证明可诱导有毒的神经元淀粉样蛋白的产生,并增强神经毒性。星形胶质细胞在 Tat 介导的淀粉样变性中的作用仍然是一个谜。我们在此报告,在感染猴免疫缺陷病毒 (SIV) 的恒河猴和诊断出 HIV 的患者中,星形胶质细胞中淀粉样前体蛋白 (APP) 和 Aβ (40 和 42) 的脑区特异性上调。此外,我们发现暴露于 Tat 的人原代星形胶质细胞 (HPAs) 中 β 位切割酶 (BACE1)、APP 和 Aβ 的表达增加。涉及缺氧诱导因子 (HIF-1α) 的上调及其易位并与长非编码 RNA (lncRNA) BACE1-反义转录本 (BACE1-AS) 结合的机制,进而形成 BACE1-AS/BACE1 RNA 复合物,随后导致 BACE1 蛋白、活性和 Aβ-42 的产生增加。基因沉默方法证实了 HIF-1α 在 Tat 介导的淀粉样变性中 BACE1-AS/BACE1 中的调节作用。这是第一个表明 HIF-1α/lncRNABACE1-AS/BACE1 轴在 Tat 介导的星形胶质细胞淀粉样变性中的作用的报告,它可以作为 HAND 相关阿尔茨海默病合并症的辅助治疗方法。
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