Mesenchymal Stem Cell Therapy for Gut Mucosal Recovery in the SIV Model of AIDS

 描述(由申请人提供)：建议的R21申请将调查间充质干细胞(MSC)在促进艾滋病毒诱导的慢性炎症性疾病的粘膜组织修复/更新和免疫恢复方面的潜力。MSCs分泌免疫调节、抗炎、抗凋亡、营养和血管生成因子，可抑制炎症和促进组织修复，目前正在几个临床试验中积极研究。然而，在感染性慢性炎症性疾病中，MSCs在组织更新中的潜力还没有得到充分的探索。HIV疾病的进展是由进行性的CD4+T细胞丧失和未解决的慢性免疫激活所推动的。HIV感染早期肠道粘膜的致病变化可能在持续性炎症和病毒库中起重要作用。抗逆转录病毒治疗显着抑制病毒复制，但不能完全解决慢性免疫激活或根除病毒库。炎症/抗炎网络的失衡导致粘膜炎症，可能是持续免疫激活的重要因素。我们建议利用猴免疫缺陷病毒(SIV)感染的非人灵长类艾滋病模型来研究MSCs潜在的治疗效果以及在组织修复和免疫恢复中的可能作用机制。感染SIV的恒河猴非常适合于研究MSC移植的治疗效益，并阐明MSC在炎症的肠道微环境中的生物作用机制。我们将验证这样一种假设，即全身应用MSC将使SIV感染猕猴黏膜部位的细胞损伤和死亡降至最低，并促进免疫恢复。这项建议利用了我们在干细胞生物学、SIV感染的恒河猴艾滋病模型、分离纯化的恒河猴MSCs以及在MSC培养、肠道粘膜免疫学和免疫激活方面的集体技术专长。这项R21提案的总体目标是研究MSC对肠道粘膜修复/更新和免疫恢复的影响，并确定SIV感染猕猴的作用机制。这项研究有两个具体目标。目的：探讨骨髓间充质干细胞(MSC)治疗对SIV感染猕猴外周血中CD4T细胞丢失、病毒载量和免疫激活/炎症的影响。目的：探讨骨髓间充质干细胞治疗对肠黏膜损伤和修复的影响，阐明其作用机制的分子网络。将测量T细胞亚群分布和细胞激活标志物(多色流式细胞仪，PCR)、炎症介质(ELISA)、病毒载量(实时PCR)、粘膜损伤和炎症(免疫组织病理学)和组织更新信号网络(Western blots和qRT-PCR)的变化。将对这些数据进行分析，以确定在感染SIV的动物中使用MSC的效果与那些没有接受MSC的动物相比。这项拟议的研究将提供一种创新的方法，通过在灵长类动物模型中应用MSC来解决HIV相关的粘膜组织损伤和慢性免疫激活问题，并将为开发新的治疗策略提供理论基础。这项研究可能阐明MSCs在慢性炎症性感染中调节免疫系统和促进肠道再生的新机制。

 DESCRIPTION (provided by applicant): The proposed R21 application will investigate the potential of mesenchymal stem/stromal cells (MSC) in enhancing mucosal tissue repair/renewal and immune recovery in HIV-induced chronic inflammatory disease. MSCs secrete immunomodulatory, anti-inflammatory, anti-apoptotic, trophic and angiogenic factors that dampen inflammation and enhance tissue repair and are being actively investigated in several clinical trials. However, the potential of MSCs in tissue renewal during chronic inflammatory diseases of infectious etiology has not been fully explored. HIV disease progression is driven by progressive CD4+ T cell loss and unresolved chronic immune activation. Early pathogenic changes in the gut mucosa in HIV infection may be important in the persistence inflammation and viral reservoirs. Antiretroviral treatment markedly suppresses viral replication but is unable to completely resolve chronic immune activation or eradicate viral reservoirs. An imbalance of inflammatory/anti-inflammatory networks, resulting in inflamed mucosa, may be an important contributor to the persistent immune activation. We propose to utilize simian immunodeficiency virus (SIV) infected non-human primate model of AIDS to investigate potential therapeutic benefits of MSCs and possible mechanisms of action in tissue repair and immune recovery. SIV-infected rhesus macaques are well suited for investigating the therapeutic benefit of MSC transplantation and to elucidate mechanisms of MSC biologic action within the inflamed gut microenvironment. We will test the hypothesis that systemic MSC administration will minimize cell injury and death at mucosal sites in the SIV infected rhesus macaques and facilitate immune recovery. This proposal leverages on our unique strengths in stem cell biology, SIV-infected rhesus macaque model of AIDS, isolation of purified rhesus macaque MSCs and collective technical expertise in MSC cultures, gut mucosal immunology and immune activation. The overall objective of this R21 proposal is to investigate the effects of MSC administration on the gut mucosal repair/renewal and immune recovery and to determine the mechanisms of action in SIV infected rhesus macaques. The study has two specific aims. Aim 1: To determine the effect of MSC therapy on CD4 T cell loss, viral loads and immune activation/inflammation in peripheral blood compartment of SIV infected macaques. Aim 2: To determine the effect of MSC therapy on gut mucosal injury and repair and elucidate the molecular networks mediating its mechanism of action. Changes in T cell subset distribution and cellular activation markers (multicolor flow cytometry, PCR), inflammatory mediators (ELISA), viral loads (real-time PCR), mucosal injury and inflammation (immunohistopathology) and signaling networks for tissue renewal (western blots and qRT-PCR) will be measured. The data will be analyzed to determine the effects of MSC administration in SIV infected animals compared to those not receiving MSC. The proposed study will provide an innovative approach to resolve HIV associated mucosal tissue damage and chronic immune activation through MSC administration in the primate model and will provide rationale for the development of novel therapeutic strategies. The study may elucidate new mechanisms by which MSCs modulate the immune system and promote gut regeneration in chronic inflammatory infections.