Toxoplasma in the GI tract: Protective role of a parasite protease inhibitor

胃肠道中的弓形虫：寄生虫蛋白酶抑制剂的保护作用

• 批准号: 10197034
• 负责人: Isabelle Coppens
• 金额: $ 20.47万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-17 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10197034
• 关键词: AIDS/HIV problem; Abbreviations; Adverse effects; Affinity; Affinity Chromatography; Animals; Antibody Affinity; Basement membrane; Binding; Biochemical; Biological Assay; Blood; Blood Circulation; Blood Vessels; Brain; Cathepsin G; Cell Death; Cells; Cessation of life; Chorioretinitis; Code; Complement; Cyst; Cytoplasmic Granules; DNA; Data; Development; Disease; Encephalitis; Enterocytes; Environment; Enzymes; Epithelial; Epithelial Cells; Event; Family; Gastrointestinal tract structure; Genes; Genetic; Goals; Histones; Human; Immune; Immune mediated destruction; Immune response; Immunocompetent; Immunocompromised Host; In Vitro; Individual; Infection; Ingestion; Internet; Intestines; Invaded; Lactoferrin; Lamina Propria; Leukocyte Elastase; Leukocyte L1 Antigen Complex; Location; Longevity; Loose connective tissue; Lymphatic; Mass Spectrum Analysis; Membrane; Monitor; Morphology; Muramidase; Mus; Muscle; Myocarditis; Myocardium; NADPH Oxidase; Names; Natural Immunity; Oocysts; Oral; Oral Administration; Oral Ingestion; Organ; Pancreatic Elastase; Parasites; Patients; Peptide Hydrolases; Phagocytosis; Pharmaceutical Preparations; Pharmacology; Pharmacotherapy; Phase; Play; Predisposition; Prevalence; Protease Inhibitor; Proteins; Recombinants; Resistance; Respiratory Burst; Risk; Role; Running; Rupture; Serine Protease; Serine Proteinase Inhibitors; Site; Skeletal Muscle; Small Intestines; Sporozoites; Stomach; Structure; Therapeutic; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Travel; Trypsin; Vaccines; Vacuole; Virulence Factors; alpha-Defensins; antimicrobial; antimicrobial peptide; assault; cell type; chemokine; chymotrypsin; extracellular; in vitro Assay; intraperitoneal; member; monocyte; muscle form; neutrophil; new therapeutic target; novel therapeutics; pathogen; response; scaffold

SUMMARY Toxoplasma gondii is an opportunistic protozoan parasite that poses a significant risk to AIDS/HIV patients. The currently available drugs for toxoplasmosis have significant adverse effects and are ineffective to eradicate long- lived tissue cysts located in the brain and muscles. Identifying new drug targets is imperative to control Toxoplasma infections with new drugs. Natural infection by T. gondii occurs via oral ingestion of tissue cysts (containing bradyzoites) or environmental oocysts (containing sporozoites). After ingestion of tissue cysts, excysted bradyzoites invade enterocytes where they transform into fast-replicating tachyzoite forms. After several cycles of replication in the small intestine and gut organs, tachyzoites migrate to the lamina propria where they enter the bloodstream to reach the brain and muscles to form tissue cysts. How Toxoplasma cysts are able to survive in the harsh environment of the stomach and gut tissues, and escape destruction by immune cells in the lamina propria remains largely unknown. Coccidian parasites (e.g., Toxoplasma), which need to be ingested orally by a host to initiate an infection, have in common the presence of genes coding for serine protease inhibitors that may target host serine proteases. Our proposal focuses on the contribution of a highly abundant serine protease inhibitor of T. gondii, named TgPI-1 to the protection of the parasite against host serine proteases present in the gut lumen (pancreatic elastase, trypsin, chymotrypsin), and/or secreted by immune cells in the lamina propria (neutrophil elastase, cathepsin G). We showed that TgPI-1 is secreted by tachyzoites and bradyzoites from dense granules, and inhibits trypsin, chymotrypsin and neutrophil elastase in vitro. Compared to wild-type parasites, TgPI-1- deficient parasites (cystogenic, type II strain) are more vulnerable to serine proteases added to the medium and have reduced dissemination in the gastro-intestinal tract of mice after oral administration of tissue cysts. Our hypothesis is that TgPI-1 contributes to the protection of T. gondii at the onset of infection in the gut. Specific Aim 1 will identify the TgPI-1 targets and sites where ΔTgPI-1 parasites are killed in the gastro-intestinal tract to reveal the sites where TgPI-1 is secreted to protect Toxoplasma in the gut. Specific Aim 2 will focus on the contribution of TgPI-1 to protect the parasite in the lamina propria by inhibiting neutrophil elastase secreted by activated neutrophils or released by dying neutrophils during extrusion of Neutrophil Extracellular Traps (NET) wherein neutrophil elastase is highly abundant. From a therapeutic point-of-view, TgPI-1 could be a newly identified virulence factor, and its pharmacological inhibition in combination with current drug treatments, may increase the efficacy of anti-Toxoplasma treatments.

总结

项目成果

MalDA, Accelerating Malaria Drug Discovery.

• DOI: 10.1016/j.pt.2021.01.009
• 发表时间: 2021-06
• 期刊: Trends in parasitology
• 影响因子: 9.6
• 作者: Yang T;Ottilie S;Istvan ES;Godinez-Macias KP;Lukens AK;Baragaña B;Campo B;Walpole C;Niles JC;Chibale K;Dechering KJ;Llinás M;Lee MCS;Kato N;Wyllie S;McNamara CW;Gamo FJ;Burrows J;Fidock DA;Goldberg DE;Gilbert IH;Wirth DF;Winzeler EA;Malaria Drug Accelerator Consortium
• 通讯作者: Malaria Drug Accelerator Consortium