Rapid chromatin remodeling of Toll-like receptor 2 promoter during infection of macrophages with Mycobacterium avium.

Mycobacterium avium Infection Induces H-Ferritin Expression in Mouse Primary Macrophages by Activating Toll-Like Receptor 2

Important for both host and pathogen survivals, iron is a key factor in determining the outcome of an infectious process. Iron with-holding, including sequestration inside tissue macrophages, is considered an important strategy to fight infection. However, for intra-macrophagic pathogens, such as Mycobacterium avium, host defence may depend on intracellular iron sequestration mechanisms. Ferrit...

NFkappaB and Sp1 elements are necessary for maximal transcription of toll-like receptor 2 induced by Mycobacterium avium.

We have previously reported that Toll-like receptor (TLR) 2 mRNA was induced after infection with Mycobacterium avium. To investigate the molecular basis of TLR2 expression in macrophages, we cloned and analyzed the murine putative 5'-proximal promoter. Transient transfection of a 326-bp region from nucleotides -294-+32 relative to the first transcription start site was sufficient to induce max...

Regulation of toll-like receptor 2 expression by macrophages following Mycobacterium avium infection.

Recent studies have implicated Toll-like receptors (TLR), especially TLR2 and TLR4, as sentinel receptors that signal the interaction of macrophages with bacterial pathogens via a NF-kappaB-mediated pathway. The regulation of TLR gene expression, however, has not been intensively studied. Here, we report that TLR2 mRNA was induced following infection of murine macrophages with Mycobacterium avi...

Mycobacterium avium Inhibition of IFN- Signaling in Mouse Macrophages: Toll-Like Receptor 2 Stimulation Increases Expression of Dominant-Negative STAT1 by mRNA Stabilization

Mice lacking myeloid differentiation factor 88 display profound defects in host resistance and immune responses to Mycobacterium avium infection not exhibited by Toll-like receptor 2 (TLR2)- and TLR4-deficient animals.

To assess the role of Toll-like receptor (TLR) signaling in host resistance to Mycobacterium avium infection, mice deficient in the TLR adaptor molecule myeloid differentiation factor 88 (MyD88), as well as TLR2(-/-) and TLR4(-/-) animals, were infected with a virulent strain of M. avium, and bacterial burdens and immune responses were compared with those in wild-type (WT) animals. MyD88(-/-) m...