Gene expression profiling of Mycobacterium avium subsp. paratuberculosis in simulated multi-stress conditions and within THP-1 cells reveals a new kind of interactive intramacrophage behaviour.
BACKGROUND
Recent studies have identified in Mycobacterium avium subsp. paratuberculosis (MAP), already known as a pathogen in ruminants, a potential zoonotic agent of some autoimmune diseases in humans. Therefore, considering the possible risk for public health, it is necessary a thorough understanding of MAP's gene expression during infection of human host as well as the identification of its immunogenic and/or virulence factors for the development of appropriate diagnostic and therapeutic tools.


RESULTS
In order to characterize MAP's transcriptome during macrophage infection, we analyzed for the first time the whole gene expression of a human derived strain of MAP in simulated intraphagosomal conditions and after intracellular infection of the human macrophage cell line THP-1 by using the DNA-microarray technology. Results showed that MAP shifts its transcriptome to an adaptive metabolism for an anoxic environment and nutrient starvation. It up-regulates several response factors to oxidative stress or intracellular conditions and allows, in terms of transcription, a passive surface peptidoglycan spoliation within the macrophage along with an intensification of the anabolic activity for lipidic membrane structures.


CONCLUSIONS
These results indicate a possible interactive system between MAP and its host cell based on the internal mimicry unlike other intracellular pathogens, bringing new hypothesis in the virulence and pathogenicity of MAP and its importance in human health.
Department of Biomedical Sciences, Division of Experimental and Clinical Microbiology, University of Sassari, Sassari, Italy. andrcossu@yahoo.it
Andrea
A
Cossu
Leonardo Antonio
LA
Sechi
Stefania
S
Zanetti
Valentina
V
Rosu
D002460:Cell Line; D006801:Humans; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology*; D046228:Microarray Analysis; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology* / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D013312:Stress, Physiological; D059467:Transcriptome