[PDF][PDF] The β-glucan receptor Dectin-1 activates the integrin Mac-1 in neutrophils via Vav protein signaling to promote Candida albicans clearance

X Li, A Utomo, X Cullere, MM Choi, DA Milner… - Cell host & …, 2011 - cell.com
X Li, A Utomo, X Cullere, MM Choi, DA Milner, D Venkatesh, SH Yun, TN Mayadas
Cell host & microbe, 2011cell.com
Resistance to fungal infections is attributed to engagement of host pattern-recognition
receptors, notably the β-glucan receptor Dectin-1 and the integrin Mac-1, which induce
phagocytosis and antifungal immunity. However, the mechanisms by which these receptors
coordinate fungal clearance are unknown. We show that upon ligand binding, Dectin-1
activates Mac-1 to also recognize fungal components, and this stepwise process is critical
for neutrophil cytotoxic responses. Both Mac-1 activation and Dectin-1-and Mac-1-induced …
Summary
Resistance to fungal infections is attributed to engagement of host pattern-recognition receptors, notably the β-glucan receptor Dectin-1 and the integrin Mac-1, which induce phagocytosis and antifungal immunity. However, the mechanisms by which these receptors coordinate fungal clearance are unknown. We show that upon ligand binding, Dectin-1 activates Mac-1 to also recognize fungal components, and this stepwise process is critical for neutrophil cytotoxic responses. Both Mac-1 activation and Dectin-1- and Mac-1-induced neutrophil effector functions require Vav1 and Vav3, exchange factors for RhoGTPases. Mac-1- or Vav1,3-deficient mice have increased susceptibility to systemic candidiasis that is not due to impaired neutrophil recruitment but defective intracellular killing of C. albicans yeast forms, and Mac-1 or Vav1,3 reconstitution in hematopoietic cells restores resistance. Our results demonstrate that antifungal immunity depends on Dectin-1-induced activation of Mac-1 functions that is coordinated by Vav proteins, a pathway that may localize cytotoxic responses of circulating neutrophils to infected tissues.
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