Browsing by Author "Benmerzouga, Imaan"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    An ensemble of specifically targeted proteins stabilizes cortical microtubules in the human parasite Toxoplasma gondii
    (American Society for Cell Biology, 2016-02-01) Liu, Jun; He, Yudou; Benmerzouga, Imaan; Sullivan, William J., Jr.; Morrissette, Naomi S.; Murray, John M.; Hu, Ke; Department of Pharmacology and Toxicology, IU School of Medicine
    Although all microtubules within a single cell are polymerized from virtually identical subunits, different microtubule populations carry out specialized and diverse functions, including directional transport, force generation, and cellular morphogenesis. Functional differentiation requires specific targeting of associated proteins to subsets or even subregions of these polymers. The cytoskeleton of Toxoplasma gondii, an important human parasite, contains at least five distinct tubulin-based structures. In this work, we define the differential localization of proteins along the cortical microtubules of T. gondii, established during daughter biogenesis and regulated by protein expression and exchange. These proteins distinguish cortical from mitotic spindle microtubules, even though the assembly of these subsets is contemporaneous during cell division. Finally, proteins associated with cortical microtubules collectively protect the stability of the polymers with a remarkable degree of functional redundancy.
  • Thumbnail Image
    Item
    Guanabenz repurposed as an antiparasitic with activity against acute and latent toxoplasmosis
    (American Society for Microbiology, 2015-11) Benmerzouga, Imaan; Checkley, Lisa A.; Ferdig, Michael T.; Arrizabalaga, Gustavo; Wek, Ronald C.; Sullivan, William J., Jr.; Department of Pharmacology and Toxicology, IU School of Medicine
    Toxoplasma gondii is a protozoan parasite that persists as a chronic infection. Toxoplasma evades immunity by forming tissue cysts, which reactivate to cause life-threatening disease during immune suppression. There is an urgent need to identify drugs capable of targeting these latent tissue cysts, which tend to form in the brain. We previously showed that translational control is critical during infections with both replicative and latent forms of Toxoplasma. Here we report that guanabenz, an FDA-approved drug that interferes with translational control, has antiparasitic activity against replicative stages of Toxoplasma and the related apicomplexan parasite Plasmodium falciparum (a malaria agent). We also found that inhibition of translational control interfered with tissue cyst biology in vitro. Toxoplasma bradyzoites present in these abnormal cysts were diminished and misconfigured, surrounded by empty space not seen in normal cysts. These findings prompted analysis of the efficacy of guanabenz in vivo by using established mouse models of acute and chronic toxoplasmosis. In addition to protecting mice from lethal doses of Toxoplasma, guanabenz has a remarkable ability to reduce the number of brain cysts in chronically infected mice. Our findings suggest that guanabenz can be repurposed into an effective antiparasitic with a unique ability to reduce tissue cysts in the brain.