The trypanosomes and leishmania are parasitic protozoa that cause African sleeping sickness, Chagas' disease and leishmaniasis. Together, these diseases afflict millions of people, and can be lethal if not treated. The available therapeutic agents are wholly unsatisfactory. The long-term objective of this work is to assess whether the type II topoisomerases, a fascinating, and relatively newly-discovered class of enzymes are a suitable target for new anti-trypanosomal chemotherapy, as suggested by pilot studies. This project will document the effects of potent, and highly specific inhibitors of type II topoisomerases (such as the anti-tumor agent, VP16-213) on the structure and replication of DNA in Trypanosoma equiperdum, and will correlate these effects with anti-trypanosomal activity in mice. The possibility that classical anti-trypanosomal drugs (ethidium bromide, pentamidine and other diamidines) have as their mechanism of action the inhibition of topoisomerases will be explored. VP16-213 and anti-trypanosomal drugs will be tested against purified mitochondrial and nuclear topoisomerases from T. equiperdum. Polyamines will be assessed as possible antagonists of the molecular and therapeutic effects of topoisomerase inhibitors, and alpha-difluoromethylornithine (an inhibitor of polyamine biosynthesis in trypanosomes) will be evaluated for possible synergy with topoisomerase inhibitors. In an effort to determine whether the nuclear and mitochondrial type II topoisomerases are different, drug-sensitive topoisomerase(s) will be isolated from nuclear and mitochondrial protein-DNA complexes, and compared with enzymes purified from nuclei and mitochondria of T. equiperdum. Evidence for a maxi- circle-encoded type II topoisomerase gene will be sought; if found, the cDNA will be sequenced and compared with that of the nuclear gene. Possible topological determinants of the drug-promoted cleavage patterns seen in vivo will be sought, using purified mitochondrial enzyme and various topological forms of minicircle DNA. These studies will expand our understanding of the role of topoisomerases in the maintenance and replication of DNA in trypanosomes. It is hoped that they will also provide a rational basis for much-needed new anti-trypanosomal chemotherapy.
| Nenortas, Nathaniel P; Cinelli, Maris A; Morrell, Andrew E et al. (2018) Activity of Aromathecins against African Trypanosomes. Antimicrob Agents Chemother 62: |
| Meyer, Kirsten J; Shapiro, Theresa A (2013) Potent antitrypanosomal activities of heat shock protein 90 inhibitors in vitro and in vivo. J Infect Dis 208:489-99 |
| Roy Chowdhury, Arnab; Bakshi, Rahul; Wang, Jianyang et al. (2010) The killing of African trypanosomes by ethidium bromide. PLoS Pathog 6:e1001226 |
| Tang, Sonya C; Shapiro, Theresa A (2010) Newly identified antibacterial compounds are topoisomerase poisons in African trypanosomes. Antimicrob Agents Chemother 54:620-6 |
| Bakshi, Rahul P; Sang, Dongpei; Morrell, Andrew et al. (2009) Activity of indenoisoquinolines against African trypanosomes. Antimicrob Agents Chemother 53:123-8 |
| Scocca, Jane R; Shapiro, Theresa A (2008) A mitochondrial topoisomerase IA essential for late theta structure resolution in African trypanosomes. Mol Microbiol 67:820-9 |
| Kulikowicz, Tomasz; Shapiro, Theresa A (2006) Distinct genes encode type II Topoisomerases for the nucleus and mitochondrion in the protozoan parasite Trypanosoma brucei. J Biol Chem 281:3048-56 |
| Bakshi, Rahul P; Shapiro, Theresa A (2004) RNA interference of Trypanosoma brucei topoisomerase IB: both subunits are essential. Mol Biochem Parasitol 136:249-55 |
| Nenortas, Elizabeth; Kulikowicz, Tomasz; Burri, Christian et al. (2003) Antitrypanosomal activities of fluoroquinolones with pyrrolidinyl substitutions. Antimicrob Agents Chemother 47:3015-7 |
| Bodley, Annette L; Chakraborty, Asit K; Xie, Suji et al. (2003) An unusual type IB topoisomerase from African trypanosomes. Proc Natl Acad Sci U S A 100:7539-44 |
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