title: Transcriptional and functional analysis of trifluoromethionine resistance in Entamoeba histolytica.
abstract: OBJECTIVE
  Drug resistance in parasitic protozoa is an obstacle to successful chemotherapy. Understanding how pathogens respond to drugs is crucial in preventing resistance. Previously, we have shown that in Entamoeba histolytica, methionine γ-lyase (EhMGL) downregulation results in trifluoromethionine resistance. The transcriptional response, however, of this parasite to the drug is not known. In this study, we used microarray analysis to determine whether additional genes are involved.
  
  
  METHODS
  The expression profiles of 9230 genes in wild-type and trifluoromethionine-resistant strains were compared. Episomal overexpression of EhBspA1 was performed to verify its role in trifluoromethionine resistance. The transcriptomes of a trifluoromethionine-resistant strain cultured with or without trifluoromethionine, an EhMGL gene-silenced strain, a strain with reduced susceptibility to metronidazole and a wild-type strain under cysteine-deprived conditions were compared to determine the specificity of the changes observed in the trifluoromethionine-resistant strain.
  
  
  RESULTS
  The expression of 35 genes differed at least 3-fold between trifluoromethionine-resistant and wild-type strains. Some of the genes play roles in metabolism, the stress response and gene regulation. EhMGL and EhBspA1 were found to be highly downregulated and upregulated, respectively. Overexpression of EhBspA1 conferred partial resistance to trifluoromethionine. Comparative transcriptome analysis showed that genes modulated in trifluoromethionine-resistant strains were specific.
  
  
  CONCLUSIONS
  E. histolytica has few known resistance mechanisms against drugs. In this study, we showed that aside from EhMGL downregulation, induction of EhBspA1 plays a role in trifluoromethionine resistance. We also showed a unique set of induced genes that could represent the signature profile of trifluoromethionine resistance in E. histolytica.
authors: Department of Parasitology,  National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640,  Japan.
authors: Gil M
authors: GM
authors: Penuliar
authors: Atsushi
authors: A
authors: Furukawa
authors: Kumiko
authors: K
authors: Nakada-Tsukui
authors: Afzal
authors: A
authors: Husain
authors: Dan
authors: D
authors: Sato
authors: Tomoyoshi
authors: T
authors: Nozaki
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D013437:Carbon-Sulfur Lyases / Q000235:genetics; D004351:Drug Resistance; D004748:Entamoeba histolytica / Q000187:drug effects* / Q000235:genetics*; D020869:Gene Expression Profiling; D000090263:Leucine-Rich Repeat Proteins; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011506:Proteins / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics
chemical_list: D000981:Antiprotozoal Agents; D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins; D015800:Protozoan Proteins; C037646:trifluoromethionine; D008715:Methionine; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase