title: Histone deacetylase inhibitor MS-275 augments expression of a subset of IFN-γ-regulated genes in Toxoplasma gondii-infected macrophages but does not improve parasite control.
abstract: Toxoplasma gondii is a ubiquitous apicomplexan parasite of mammals and birds and an important pathogen of humans. IFN-γ is the major mediator of host resistance against T. gondii but intriguingly, parasite-infected host cells including macrophages are severely impaired to respond to IFN-γ due to defective transcriptional activation of target genes. Here, we tested the possibility that the impaired responsiveness of T. gondii-infected macrophages to IFN-γ can be restored by inhibiting histone deacetylases (HDACs) using the class I-specific inhibitor MS-275. Treatment of RAW264.7 cells with MS-275 indeed increased MHC class II surface expression in infected and non-infected cells and largely abolished the inhibition of IFN-γ-regulated MHC class II expression exerted by T. gondii. Genome-wide transcriptome profiling revealed that MS-275 increased mean mRNA levels of IFN-γ-regulated genes particularly in non-infected macrophages. Transcript levels of 33% of IFN-γ secondary response genes but only those of a few primary response genes were also increased by MS-275 in T. gondii-infected cells. Importantly, the unresponsiveness of parasite-infected cells to IFN-γ was however not abolished by MS-275. Furthermore, MS-275 also up-regulated several anti-inflammatory cytokines or signaling molecules in T. gondii-infected macrophages. It additionally regulated expression of more than 2500 genes in non-infected macrophages expression of which was surprisingly counteracted by prior infection with T. gondii. FACS analysis and immunofluorescence microscopy revealed that MS-275 did not considerably diminish the number of parasite-positive cells or the intracellular replication in macrophages stimulated or not with IFN-γ. Thus, a supportive therapy using MS-275 appears inappropriate for treatment of toxoplasmosis.
authors.affiliation: Institute for Medical Microbiology, University Medical Center, Georg-August-University, Kreuzbergring 57, 37075 Göttingen, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sumpf
authors.affiliation: Institute for Medical Microbiology, University Medical Center, Georg-August-University, Kreuzbergring 57, 37075 Göttingen, Germany.
authors.forename: Roswitha
authors.initials: R
authors.lastname: Nast
authors.affiliation: Transcriptome and Genome Analysis Laboratory, University Medical Center, Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
authors.forename: Bryan
authors.initials: B
authors.lastname: Downie
authors.affiliation: Transcriptome and Genome Analysis Laboratory, University Medical Center, Georg-August-University, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Salinas
authors.affiliation: Institute for Medical Microbiology, University Medical Center, Georg-August-University, Kreuzbergring 57, 37075 Göttingen, Germany. Electronic address: clueder@gwdg.de.
authors.forename: Carsten G K
authors.initials: CGK
authors.lastname: Lüder
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology*; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects*; D005802:Genes, MHC Class II / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases / Q000187:drug effects; D007371:Interferon-gamma / Q000235:genetics* / Q000502:physiology; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000469:parasitology; D051379:Mice; D008856:Microscopy, Fluorescence; D011725:Pyridines / Q000494:pharmacology*; D000067996:RAW 264.7 Cells; D016053:RNA, Protozoan / Q000737:chemistry / Q000302:isolation & purification; D014122:Toxoplasma / Q000187:drug effects* / Q000235:genetics / Q000276:immunology
chemical_list: D001549:Benzamides; D056572:Histone Deacetylase Inhibitors; D011725:Pyridines; D016053:RNA, Protozoan; C118739:entinostat; D007371:Interferon-gamma; D006655:Histone Deacetylases
keywords: Histone deacetylase; Immune evasion; Interferon-gamma; MS-275; Supportive therapy; Toxoplasma gondii