Sensing of mycobacterial arabinogalactan by galectin-9 exacerbates mycobacterial infection by inducing matrix metalloproteinases
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ABSTRACT: Mycobacterial arabinogalactan (AG) is an essential cell wall component of Mycobacteria and a frequent structural and bio-synthetical target for anti-tuberculosis (TB) drug development. Yet, it is unclear whether mycobacterial AG is a pathogen-associated molecular pattern (PAMP) with an elusive pattern recognition receptor (PRR). Here, we report that mycobacterial AG is recognized by galectin-9 and exacerbates mycobacterial infection. Administration of AG-specific aptamers inhibited cellular infiltration caused by Mycobacterium tuberculosis (Mtb) or Mycobacterium bovis BCG, and moderately increased survival of Mtb-infected mice or Mycobacterium marinum-infected zebrafish. AG interacted with carbohydrate recognition domain (CRD) 2 of galectin-9 with high affinity, and galectin-9 associated with transforming growth factor β-activated kinase 1 (TAK1) via CRD2 to trigger subsequent activation of extracellular signal-regulated kinase (ERK) as well as induction of the expression of matrix metalloproteinases (MMPs). Moreover, deletion of galectin-9 or inhibition of MMPs blocked AG-induced pathological impairments in the lung, and the AG-galectin-9 axis aggravated the process of Mtb infection in mice. These results demonstrate that AG is an important virulence factor of mycobacteria and galectin-9 is a novel receptor for Mtb and other mycobacteria, paving the way for the development of novel effective TB immune modulators.
ORGANISM(S): Mus musculus
PROVIDER: GSE166850 | GEO | 2021/02/17
REPOSITORIES: GEO
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