CCN1 is an opsonin for bacterial clearance and a direct activator of Toll-like receptor signaling

Nat Commun. 2020 Mar 6;11(1):1242. doi: 10.1038/s41467-020-15075-5.


Expression of the matricellular protein CCN1 (CYR61) is associated with inflammation and is required for successful wound repair. Here, we show that CCN1 binds bacterial pathogen-associated molecular patterns including peptidoglycans of Gram-positive bacteria and lipopolysaccharides of Gram-negative bacteria. CCN1 opsonizes methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa and accelerates their removal by phagocytosis and increased production of bactericidal reactive oxygen species in macrophages through the engagement of integrin αvβ3. Mice with myeloid-specific Ccn1 deletion and knock-in mice expressing CCN1 unable to bind αvβ3 are more susceptible to infection by S. aureus or P. aeruginosa, resulting in increased mortality and organ colonization. Furthermore, CCN1 binds directly to TLR2 and TLR4 to activate MyD88-dependent signaling, cytokine expression and neutrophil mobilization. CCN1 is therefore a pattern recognition receptor that opsonizes bacteria for clearance and functions as a damage-associated molecular pattern to activate inflammatory responses, activities that contribute to wound healing and tissue repair.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cysteine-Rich Protein 61 / genetics
  • Cysteine-Rich Protein 61 / immunology
  • Cysteine-Rich Protein 61 / metabolism*
  • Disease Models, Animal
  • Disease Susceptibility
  • Female
  • Gene Knock-In Techniques
  • Gene Knockdown Techniques
  • Humans
  • Integrin alphaVbeta3 / immunology
  • Integrin alphaVbeta3 / metabolism
  • Male
  • Methicillin-Resistant Staphylococcus aureus
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Opsonin Proteins / genetics
  • Opsonin Proteins / metabolism*
  • Pathogen-Associated Molecular Pattern Molecules / metabolism
  • Phagocytosis / immunology
  • Pseudomonas Infections / immunology*
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / immunology
  • Sf9 Cells
  • Signal Transduction / immunology
  • Staphylococcal Infections / immunology*
  • Staphylococcal Infections / microbiology
  • Toll-Like Receptors / immunology
  • Toll-Like Receptors / metabolism*


  • CCN1 protein, mouse
  • Cysteine-Rich Protein 61
  • Integrin alphaVbeta3
  • Opsonin Proteins
  • Pathogen-Associated Molecular Pattern Molecules
  • Toll-Like Receptors