title: A screening pipeline for antiparasitic agents targeting cryptosporidium inosine monophosphate dehydrogenase.
abstract: BACKGROUND
  The protozoan parasite Cryptosporidium parvum is responsible for significant disease burden among children in developing countries. In addition Cryptosporidiosis can result in chronic and life-threatening enteritis in AIDS patients, and the currently available drugs lack efficacy in treating these severe conditions. The discovery and development of novel anti-cryptosporidial therapeutics has been hampered by the poor experimental tractability of this pathogen. While the genome sequencing effort has identified several intriguing new targets including a unique inosine monophosphate dehydrogenase (IMPDH), pursuing these targets and testing inhibitors has been frustratingly difficult.
  
  
  RESULTS
  Here we have developed a pipeline of tools to accelerate the in vivo screening of inhibitors of C. parvum IMPDH. We have genetically engineered the related parasite Toxoplasma gondii to serve as a model of C. parvum infection as the first screen. This assay provides crucial target validation and a large signal window that is currently not possible in assays involving C. parvum. To further develop compounds that pass this first filter, we established a fluorescence-based assay of host cell proliferation, and a C. parvum growth assay that utilizes automated high-content imaging analysis for enhanced throughput.
  
  
  CONCLUSIONS
  We have used these assays to evaluate C. parvum IMPDH inhibitors emerging from our ongoing medicinal chemistry effort and have identified a subset of 1,2,3-triazole ethers that exhibit excellent in vivo selectivity in the T. gondii model and improved anti-cryptosporidial activity.
authors: Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America.
authors: Lisa
authors: L
authors: Sharling
authors: Xiaoping
authors: X
authors: Liu
authors: Deviprasad R
authors: DR
authors: Gollapalli
authors: Sushil K
authors: SK
authors: Maurya
authors: Lizbeth
authors: L
authors: Hedstrom
authors: Boris
authors: B
authors: Striepen
mesh_terms: D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001331:Automation; D016785:Cryptosporidium parvum / Q000187:drug effects* / Q000201:enzymology*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D057166:High-Throughput Screening Assays / Q000379:methods; D006801:Humans; D007168:IMP Dehydrogenase / Q000037:antagonists & inhibitors*; D007091:Image Processing, Computer-Assisted; D013194:Staining and Labeling; D014122:Toxoplasma / Q000201:enzymology / Q000235:genetics; D014230:Triazoles / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000981:Antiprotozoal Agents; D004791:Enzyme Inhibitors; D014230:Triazoles; D007168:IMP Dehydrogenase