[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]
Drug Repurposing Screen Reveals FDA-Approved Inhibitors of Human HMG-CoA Reductase and Isoprenoid Synthesis that Block Cryptosporidium parvum Growth
Kovi Bessoff 1, Adam Sateriale 2, K. Kyungae Lee 3 and Christopher D. Huston 1,2,4,*
Author Affiliations: 1Department of Microbiology and Molecular Genetics, University of Vermont College of Medicine, Burlington, VT, USA 2Cell, Molecular, and Biomedical Science Graduate Program, University of Vermont College of Medicine, Burlington, VT, USA 3New England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases, Harvard Medical School, Boston, MA 02115, USA 4Department of Medicine, University of Vermont College of Medicine, Burlington, VT, USA
Cryptosporidiosis, a diarrheal disease usually caused by Cryptosporidium parvum or Cryptosporidium hominis in humans, can result in fulminant diarrhea and death in AIDS patients, and chronic infection and stunting in children. Nitazoxanide, the current standard of care, has limited efficacy in children and is no more effective than placebo in patients with advanced AIDS. Unfortunately, the lack of financial incentives and the technical difficulties associated with working with Cryptosporidium parasites have crippled efforts to develop effective treatments. In order to address these obstacles, we developed and validated (Z’ score = 0.21-0.47) a cell-based high throughput assay and screened a library of drug repurposing candidates (the NIH Clinical Collections) with the hopes of identifying safe, FDA-approved drugs to treat cryptosporidiosis. Our screen yielded 21 compounds with confirmed activity against C. parvum growth at concentrations <10 μM, many of which had well-defined mechanisms of action, making them useful tools to study basic biology in addition to being potential therapeutics. Additional work including structure activity relationship studies identified the human 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitor itavastatin as a potent inhibitor of C. parvum growth (IC50= 0.62 μM). Bioinformatic analysis of the Cryptosporidium genomes indicated that the parasites lack all known enzymes required for the synthesis of isoprenoid precursors. Additionally, itavastatin-induced growth inhibition of C. parvum was partially reversed by the addition of exogenous isopentenyl pyrophosphate, suggesting that itavastatin reduces Cryptosporidium growth via on-target inhibition of host HMG-CoA reductase and that the parasite is dependent on the host cell for synthesis of isoprenoid precursors.
*Correspondent footnote: Please send correspondence regarding this paper to C.D.H. at firstname.lastname@example.org
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