Correction of Hurler syndrome by multipotent stem cells

描述(由申请人提供)：需要基于病理生理机制的新方法来治疗进行性神经功能障碍和赫勒综合征(MPS I)的智力低下。本课题组已经在人和啮齿动物的骨髓(BM)中发现了一种多能成体祖细胞(MAPC)，它在体外和体内分化为所有三种胚胎谱系，包括神经元和神经胶质细胞(血液98：2615,2001；自然418：41,2002)。将MAPC植入成年啮齿动物脑移植，获得神经元和神经胶质标记物，改善缺血性神经功能障碍。MAPC可能是神经组织重建/基因传递的理想材料，因为它们1)从小的骨髓样本中获得并在没有衰老的情况下增殖2)被有效地转导和表达基因而不会失去干细胞潜能3)不受胚胎/胎儿组织的伦理问题的影响。在R03的资助中，我们发现1)Hurler MAPC中结构异常的硫酸乙酰肝素(HS)与成纤维细胞生长因子-2的结合存在缺陷，从而削弱了其对MAPC存活、增殖和神经分化的生物活性。2)正常MAPC向Hurler MAPC提供营养和纠正信号。3)Hurler MAPC中蛋白多糖(PGs)、糖胺聚糖(GAG)代谢酶、细胞因子和形态因子的基因表达发生变化。另外，本课题组在MPS I基因敲除小鼠模型中发现了严重的神经病理和行为异常。我们假设：1)HS的结构和功能异常通过扰乱关键细胞因子的生物活性和辅助调节基因表达而参与了Hurler综合征的神经元病理生理；2)脑室内移植后，正常的人MAPC将移植到新生免疫缺陷(NOD-SCID)-MPS I小鼠的大脑中，并改善行为异常。特异性目的(SA)1：比较正常和Hurler MAPC及小鼠脑组织HS的结构和功能。SA2：测试累积的GAG和寡糖对Hurler MAPC中HS生物合成和基因表达的次要影响。SA3：检测正常人MAPC脑室内移植能否纠正NOD-SCID-MPS I小鼠的神经病理和行为障碍。如果MAPC移植在Hurler模型中是有益的，那么类似的策略可能会被开发出来用于治疗各种神经退行性疾病。

DESCRIPTION (provided by applicant): Novel approaches based on pathophysiologic mechanisms are needed to treat progressive neurological dysfunction and mental retardation in Hurler syndrome (MPS I). Our group has identified a multipotent adult progenitor cell (MAPC) in human and rodent bone marrow (BM), which differentiates in vitro and in vivo into all three embryonic lineages, including neuronal and glial cells (Blood 98:2615, 2001; Nature 418:41, 2002). MAPC implanted into adult rodent brains engraft, acquire neuronal and glial markers and ameliorate ischemic neurological dysfunction. MAPC may be ideal for neural tissue reconstitution/gene delivery, as they 1) are obtained from a small BM sample and proliferate without senescence 2) are efficiently transduced and express genes without losing stem cell potential 3) are free from ethical issues of embryonic/fetal tissues. During an R03 grant, we found that 1) structurally abnormal heparan sulfates (HS) in Hurler MAPC have defective binding interactions with FGF-2, thus impairing its biological activity on MAPC survival, proliferation and neural differentiation 2) normal MAPC provide trophic and corrective signals to Hurler MAPC 3) gene expression of proteoglycans (PGs), glycosaminoglycan (GAG) metabolic enzymes, cytokines and morphogens is altered in Hurler MAPC. Separately, our group found severe neuropathological and behavioral abnormalities in a murine knockout model of MPS I. We hypothesize that 1) the structural and functional abnormalities of HS contribute to the neuronal pathophysiology of Hurler syndrome by perturbing the biological activity of critical cytokines and by secondarily modulating gene expression, and 2) following intra-ventricular transplantation, normal human MAPC will engraft in the brain of neonatal immunodeficient (NOD-SCID)-MPS I mice and ameliorate behavioral abnormalities. Specific Aim (SA) 1: Compare the structure and function of HS from normal and Hurler MAPC and murine brain tissue. SA2: Test the secondary effects of accumulated GAGs and oligosaccharides on HS biosynthesis and gene expression in Hurler MAPC. SA3: Examine if the neuropathology and behavioral dysfunction in NOD-SCID-MPS I mice can be corrected by intracerebroventricular transplantation of normal human MAPC. If MAPC transplantation is of benefit in the Hurler model, similar strategies may be developed for treating diverse neurodegenerative disorders.