Implication of HUCBC: a novel therapeutic strategy for Alzheimer's disease

描述（由申请人提供）：人脐带血细胞（HUCBC）是众所周知的特异性免疫调节剂，赋予外周和中枢免疫反应平衡（即没有完全的免疫抑制，GVHD或排斥）改变。其他研究人员已经证明它们促进成人骨髓（BM）祖细胞的动员。此外，我们最近证明了hubc注入papp小鼠的血清显著抑制IFN-？并显著增加小胶质细胞A¿的吞噬活性，而没有不可接受的免疫损害。证实，CD40与CD40L蛋白的连接可以抑制这种作用。重要的是，这些hubc注入小鼠的初级成年小胶质细胞也显示出增加的A¿吞噬活性和强A¿IgG滴度。综上所述，这些数据表明，由HUCBC诱导的CD40信号抑制和a¿IgG产生增强介导的先天和体液免疫微环境的平衡改变。与神经毒性先天反应的下调和有益体液反应的上调一致，A¿水平/¿-淀粉样蛋白沉积和脑淀粉样蛋白血管病(CAA；体内输注HUCBC可降低血管淀粉样蛋白沉积的炎症反应，同时伴有：(a)血清a¿1- 40,42水平升高，提示来自中枢神经系统的外排(b)血清可溶性CD40L水平降低，(c)小胶质细胞CD40表达降低，最后(d) CNS/血清抗炎（IL-10和TGF-21）水平升高，促炎细胞因子（IL-1和TNF-a）减少。最后，我们的初步数据表明，与对照原代BM来源的单核/巨噬细胞（MO/X）相比，hubc输注的papp小鼠的MO/X显示出增强的A¿吞噬活性。这些数据以及我们之前的研究结果，即Tg2576小鼠与CD40L缺失小鼠杂交或用CD40L抗体治疗papp小鼠可减少A¿负荷，使我们假设，通过CD40-CD40L破坏介导的先天和体液免疫的改变，导致bm来源的祖细胞MO/X的动员，增加抗炎细胞因子的产生，HUCBC输注可以减轻阿尔茨海默病（AD）小鼠的A¿/¿-淀粉样蛋白病理。大脑中淀粉样蛋白的清除也增加了。在这里，我们提出通过研究hubc注入的papp小鼠中的CD40信号传导来验证hubc介导的CD40- cd40l相互作用抑制淀粉样变性的假设。根据我们的初步数据，我们还计划通过单独或联合给药IL- 10、TGF-¿1和NGF-¿来重建HUCBC输注的作用；我们发现的关键因素对于HUCBC调节CD40活性和淀粉样变性的能力至关重要，而不会产生全身免疫抑制、排斥或GVHD。此外，我们将验证hubc输注调动bm来源的MO/X的假设，导致巨噬细胞转分化进入中枢神经系统，并进一步分化为具有增强的A¿吞噬能力的小胶质细胞。我们的长期目标是将这种联合治疗推向轻度至中度AD患者的I期人体试验。公共卫生相关性：在过去的几年里，我们已经表明，通过CD40-CD40L系统的信号中断减少了过量产生APP（淀粉样蛋白前体蛋白）的转基因小鼠大脑中的淀粉样蛋白沉积，同时改善了认知缺陷。CD40阻断通过减缓活化的小胶质细胞的成熟，从而维持吞噬表型，同时减少中枢神经系统中潜在神经毒性细胞因子（IL- 2和TNF-）的产生，并增加治疗性抗炎细胞因子（IL-10和TGF-21）的产生。最重要的是，我们证明了这种吞噬小胶质细胞表型增强了脑实质中淀粉样斑块的清除。不幸的是，CD40阻断具有不可接受的免疫消耗副作用，这使得该策略不适合转移到临床环境中。人脐带血细胞（HUCBC）是众所周知的特异性免疫调节剂，它赋予外周和中枢、先天和体液免疫反应的平衡改变，而不会产生排斥反应或全身免疫抑制。为了支持这一观点，我们的初步数据显示，输注hucbc的小鼠外周血抗原呈递细胞（APCs）中CD40的表达及其信号功能不受影响，而CNS中的细胞吞噬活性增加，毒性细胞因子下调，抗炎细胞因子的产生增加。因此，本申请提出通过研究hubc注入papp小鼠的CD40信号传导，来研究hubc介导的CD40- cd40l相互作用抑制淀粉样变性的假设。此外，我们计划研究可溶性因子，包括IL-10、TGF-¿1和NGF-¿（这些因子在hucbc输注小鼠中显著升高），它们调节CD40-CD40L相互作用，减少淀粉样蛋白实质负荷，在这种情况下，我们的长期目标是开发一种用于人体试验的联合治疗。最后，确定hubc输注papp小鼠后骨髓来源的MO/X的贡献。总之，预期的结果将表明，HUCBC或HUCBC诱导的分离可溶性因子将是一种新的治疗AD的策略。

DESCRIPTION (provided by applicant): Human umbilical cord blood cells (HUCBC) are well known specific immunomodutators that confer a balanced (i.e. without complete immunosuppression, GVHD, or rejection) alteration of both peripheral and central immune responses. Other investigators have demonstrated they promote mobilization of adult bone marrow (BM) progenitor cells. In addition we recently demonstrated sera derived from HUCBC-infused PSAPP mice significantly inhibited microglial CD40 expression induced by IFN-? and markedly increased microglial A¿ phagocytic activity without unacceptable immune compromise. In confirmation, this effect was inhibited by the ligation of CD40 with CD40L protein. Importantly, primary adult microglia from these HUCBC-infused mice also showed increased A¿ phagocytic activity, and a strong A¿ IgG titer. Together these data suggest a balanced alteration of both innate and humoral immune microenvironments mediated by an HUCBC induced suppression of CD40 signaling and enhancement of A¿ IgG production. In accord with this downregulation of neurotoxic innate responses and upregulation of salutary humoral responses, A¿ levels/¿- amyloid deposits and cerebral amyloid angiopathy (CAA; an inflammatory response to vascular amyloid deposits) are reduced by HUCBC infusion in vivo, with attendant: (a) increased serum levels of A¿1-40, 42, suggesting efflux from the CNS (b) decreased soluble CD40L serum levels, (c) decreased microglial CD40 expression, and finally, (d) elevated CNS/serum levels of anti-inflammatory (IL-10 and TGF-21) with decrease pro-inflammatory cytokines (IL-1¿ and TNF-a). Finally, our preliminary data suggests that, compared with control primary BM derived monocytes/macrophages (MO/X), MO/X from HUCBC-infused PSAPP mice show enhanced A¿ phagocytic activity. These data along with our previous findings that crossing Tg2576 mice with CD40L null mice or treating PSAPP mice with CD40L antibody reduced A¿ loads, lead us to hypothesize that HUCBC infusion confers a mitigation of A¿/¿-amyloid pathology in Alzheimer's disease (AD) mice by alterations in innate and humoral immunity mediated by CD40-CD40L disruption resulting in mobilization of BM-derived progenitor MO/X, increased anti-inflammatory cytokine production, and increased amyloid clearance from the brain. Here we propose to test the hypothesis that HUCBC mediated dampening of the CD40-CD40L interaction reduces amyloidosis by investigating CD40 signaling in HUCBC infused PSAPP mice. Based on our preliminary data, we additionally plan to reconstitute the effects of HUCBC infusion by administering IL- 10, TGF-¿1 and NGF-¿ alone and in combinations; key factors we found to be essential for HUCBC ability to modulate CD40 activity and amyloidosis without systemic immunosuppression, rejection, or GVHD. Also, we will test the hypothesis that HUCBC infusion mobilizes BM-derived MO/X, leading to transdifferentiation into macrophages which enter the CNS and further differentiate into microglia with enhanced A¿ phagocytic capacity. It is our long-term goal to move this combination treatment into phase I human trials for patients with mild to moderate AD. PUBLIC HEALTH RELEVANCE: In the past years, we have shown that disruption of signaling through the CD40-CD40L system reduces amyloid deposition in the brains of APP (amyloid precursor protein) overproducing transgenic mice while ameliorating cognitive deficits. The CD40 blockade acts by slowing maturation of activated microglia thereby maintaining a phagocytic phenotype with concurrent decreased production of potentially neurotoxic cytokines (IL-¿2 and TNF-¿), and increased production of therapeutic anti-inflammatory cytokines (IL-10 and TGF-21) in the CNS. Most importantly this we demonstrated this phagocytic microglial phenotype enhances clearance of amyloid plaques from the brain parenchyma. Unfortunately CD40 blockade carries with it unacceptable immune-depleting side effects which makes this strategy less than optimal for transfer to the clinical setting. Human umbilical cord blood cells (HUCBC) are well known specific immunomodutators that confer a balanced alteration of peripheral and central, innate and humoral immune responses without rejection or systemic immunosuppression. In support, our preliminary data showed that CD40 expression and its signaling functions in peripheral antigen presenting cells (APCs) from HUCBC-infused mice are not affected, while those in the CNS experience increased phagocytic activity, down regulation of toxic cytokines, and increased generation of anti-inflammatory cytokines. Thus, this application proposes to investigate the hypothesis that HUCBC mediated dampening of the CD40-CD40L interaction reduces amyloidosis by investigating CD40 signaling in HUCBC infused PSAPP mice. Furthermore, we plan to investigate the soluble factors, including IL-10, TGF-¿1 and NGF-¿ (these factors significantly elevated in HUCBC-infused mice), which modulate the CD40-CD40L interaction and reduced amyloid parenchymal load in this context with the long term goal of developing a combination treatment for use in human trials. Finally, the contribution of bone marrow-derived MO/X after HUCBC infusion into PSAPP mice will be determined. In summary, the expected results will suggest that HUCBC or, isolated soluble factors that HUCBC induce, would be a novel therapeutic strategy for AD.