The role of Toxoplasma gondii amino acid hydroxylase 2 in chronic infection

弓形虫氨基酸羟化酶2在慢性感染中的作用

• 批准号: 9120661
• 负责人: Nicole D. Marino
• 金额: $ 3.55万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9120661
• 关键词: Affect; Amino Acids; Antibodies; Automobile Driving; Back; Behavior; Behavioral; Biology; Bobcat; Brain; Cells; Chorioretinitis; Chronic; Cyst; Differentiation and Growth; Disease; Dopa; Dopamine; Encephalitis; Enzymes; Evolution; Family Felidae; Felis catus; Fright; Gastrointestinal tract structure; Gilles de la Tourette syndrome; Goals; Growth; Harvest; Health; High Pressure Liquid Chromatography; Human; Immune response; Immune system; Immunocompromised Host; In Vitro; Individual; Infection; Knowledge; Link; Measures; Mental disorders; Metabolism; Microscopy; Mission; Mixed Function Oxygenases; Mus; Neurons; Neurotransmitters; Nutrient; Odors; Oral; Oryctolagus cuniculus; PC12 Cells; Parasite Control; Parasites; Parasitic infection; Parkinson Disease; Pepsin A; Phenylalanine; Plaque Assay; Population; Process; Reaction; Reporting; Rodent; Role; Schizophrenia; Staging; Staining method; Stains; Stomach; Testing; Time; Tissues; Toxoplasma; Toxoplasma gondii; Tyrosine; Tyrosine Metabolism Pathway; Urine; Vacuole; Work; amino acid metabolism; crosslink; cytokine; dityrosine; dopaminergic neuron; feeding; insight; mutant; neurochemistry; nutrition; preference; public health relevance; seroconversion; seropositive; therapeutic development; transmission process

 DESCRIPTION (provided by applicant): Toxoplasma infection has been linked to a variety of mental disorders and behavioral alterations, including schizophrenia and Parkinson's disease. Interestingly, chronic Toxoplasma infection has been shown to increase dopamine levels and alter behavior in rodents, causing them to lose their innate fear of cat odors. Because the feline is the definitive host for Toxoplasma, it has been proposed that evolution has selected for a parasite that alters rodent behavior to increase its transmission back to the cat. Importantly, Toxoplasma increases dopamine content and secretion in neurons in vitro, suggesting that the parasite can increase dopamine metabolism independently of the immune system. It has been proposed that Toxoplasma alters dopamine and behavior using amino acid hydroxylase 2 (TgAAH2), which it expresses during chronic infection. AAH2 catalyzes the conversion of phenylalanine to tyrosine and tyrosine to DOPA, with preference for the latter reaction. Because the conversion of tyrosine to DOPA is the rate-limiting step in dopamine synthesis, Toxoplasma may increase dopamine by catalyzing the formation of DOPA, the direct precursor to dopamine. The overarching goal of this work is to determine the role of AAH2 in chronic infection, dopamine metabolism, and behavioral alteration in rodents. Previous reports show that the tissue cyst wall Toxoplasma forms during chronic infection consists of dityrosine crosslinks and DOPA, suggesting a structural role for this enzyme. The hypothesis driving this work is that AAH2 regulates amino acid metabolism during differentiation to the encysted form, contributes to formation of the cyst wall, and/or alters dopamine metabolism and behavior in the rodent host. To determine if AAH2 is important for amino acid metabolism and nutrition, growth and differentiation of the AAH2 mutant and control strains in nutrient-rich and tyrosine-deficient media will be measured by plaque assay and microscopy. To determine if AAH2 is important for synthesizing DOPA and dityrosines in the tissue cyst wall, the brains of mice chronically infected with the AAH2 mutant and control strains will be fixed, harvested, processed into sections, and stained with antibodies for dityrosine and DOPA. The infectivity of the AAH2 mutant and control cysts during passage through the gastric tract will be measured by orally infecting naïve mice and measuring seroconversion and dissemination to the brain. Structural integrity of the cyst wall will be determined by treating cysts with pepsin digestive solution and measuring parasite viability by plaque assay. To determine if AAH2 affects neurotransmitter levels during chronic infection, HPLC-ED will be performed on neurons infected with the AAH2 mutant and controls. To determine if AAH2 affects behavior in rodents, the behavior of mice around bobcat or rabbit urine during chronic infection with these strains will be measured. The completion of this work will identify the function of AAH2 during chronic Toxoplasma infection, for which there is no cure or treatment. Furthermore, it will test whether AAH2 contributes to dopamine dysregulation and behavioral alteration.

 描述（通过应用程序证明）：弓形虫感染已与多种精神障碍和行为高度有关，奥弗伦尼亚和帕金森氏病，慢性上洛氏感染已显示出topamine水平和啮齿动物的改变，使他们失去了对猫的恐惧的恐惧。羟化酶2（TGAAH2）对酪氨酸和DOPA的酪氨酸，具有后一种反应。在慢性感染，多巴胺代谢和行为高度的AAH2中。和/或在啮齿动物宿主中改变多巴胺的代谢和行为。显微镜。确定AAH2是否对于组织囊肿壁中的DITYROSINE是否很重要，将小鼠的大脑长期固定为AAH2突变体和对照菌株，并将其收获到Dityrosine和Dopa的安全性IES中。在口服幼体的小鼠和囊肿的结构完整性中，胃部的胃肠症将通过口服幼稚。如果AAH2在慢性毒品感染期间，AAH2在慢性感染期间会影响啮齿动物OBCAT或兔子尿液中AAH2的功能，请在具有AAH2 MUTTEME的神经元上进行。