Receptors for Neuron and Glia Survival in Chagas Disease

由原生动物克氏锥虫（Trypanosoma cruzi）引起的恰加斯病患者表现出急性期，其特征在于强劲的寄生虫生长和神经变性;无症状的不确定的慢性期，其特征在于神经元的再生;以及慢性期，其特征在于免疫学改变和神经元的巨大变性。 大多数患者仍处于不确定阶段数年或数十年。一些无症状的患者进展到慢性、致命的慢性病阶段。 为什么病人可以保持无症状，并有神经再生的迹象，而其他人则发展神经变性，这仍然是一个谜。最近的研究表明，T. cruzi是几种类型神经元以及神经胶质雪旺细胞和星形胶质细胞的有效存活因子。 TS可以像神经生长因子（NGF）一样保护交感神经样PC 12细胞免受饥饿引起的凋亡。 此外，TS与白细胞介素-6家族的细胞因子协同作用以保护神经元。 同样，TS与neureglin和其他促进神经胶质雪旺细胞存活的生长因子一样好。 然而，TS与NGF和其他嗜中性粒细胞因子以及细胞因子神经营养因子没有可检测的同源性。 因此，TS如何促进神经元和神经胶质细胞的存活仍然是未知的。理解T的最好方法cruzi诱导的存活是了解TS与神经元和神经胶质细胞上的受体反应的性质。 本项目试图鉴定T. cruzi用于在神经系统入侵期间促进细胞存活。 该项目将利用细胞生物学、生物化学、遗传学和免疫化学方法的最新组合来识别和表征相关受体。 这些研究的结果可以很好地提供对恰加斯病发病机制的见解，并导致开发不仅治疗恰加斯病而且治疗其他神经退行性疾病的化合物。

Patients with Chagas' disease, caused by the protozoan Trypanosoma cruzi, exhibit an acute stage, characterized by robust parasite growth and neural degeneration; an asymptomatic indeterminate chronic phase, marked by the regeneration of neurons; and a chronic phase, designated by immunological alterations and tremendous degeneration of neurons. Most patients remain in the indeterminate phase for years or decades. Some asymptomatic patients progress to the chronic, fatal chronic disease stage. It remains a mystery why patients can remain asymptomatic and with signs of neural regeneration for life while others develop neuro-degeneration. Recent studies demonstrate that the trans-sialidase (TS) of T. cruzi is a potent survival factor for several types of neurons, and for glial Schwann cells and astrocytes. TS can be as good as nerve growth factor (NGF) in protecting sympathetic-like PC12 cells against apoptosis provoked by starvation. In addition, TS synergizes with cytokines of the interleukin-6 family to protect neurons. Likewise, TS is as good as neureglin and other growth factors that promote survival of glial Schwann cells. Yet, TS has no detectable homology to NGF and other neutrophins, and to cytokine neurotrophic factors. Thus, it remains unknown how TS promotes survival of neurons and glial cells. The best way to understand T. cruzi-induced survival is to know the nature of the receptors TS react with on neurons and glial cells. This project attempts to identify TS receptors that T. cruzi uses to promote cell survival during invasion of the nervous system. The project will utilize a state-or-the-art combination of cell biology, biochemistry, genetics, and immunochemical approaches to identify and characterize relevant receptors. The outcome of the studies could very well provide insights into the pathogenesis of Chagas' disease and to lead to the development of compounds to treat not only Chagas' disease but also other neurodegenerative disorders.