Wiskott-Aldrich syndrome protein-mediated actin dynamics control type-I interferon production in plasmacytoid dendritic cells

Francesca Prete, Marco Catucci, Mayrel Labrada, Stefania Gobessi, Maria Carmina Castiello, Elisa Bonomi, Alessandro Aiuti, William Vermi, Caterina Cancrini, Ayse Metin, Sophie Hambleton, Robbert Bredius, Luigi Daniele Notarangelo, Mirjam van der Burg, Ulrich Kalinke, Anna Villa, Federica Benvenuti

Research output: Contribution to journalArticlepeer-review


Mutations in Wiskott-Aldrich syndrome (WAS) protein (WASp), a regulator of actin dynamics in hematopoietic cells, cause WAS, an X-linked primary immunodeficiency characterized by recurrent infections and a marked predisposition to develop autoimmune disorders. The mechanisms that link actin alterations to the autoimmune phenotype are still poorly understood. We show that chronic activation of plasmacytoid dendritic cells (pDCs) and elevated type-I interferon (IFN) levels play a role in WAS autoimmunity. WAS patients display increased expression of type-I IFN genes and their inducible targets, alteration in pDCs numbers, and hyperresponsiveness to TLR9. Importantly, ablating IFN-I signaling in WASp null mice rescued chronic activation of conventional DCs, splenomegaly, and colitis. Using WASp-deficient mice, we demonstrated that WASp null pDCs are intrinsically more responsive to multimeric agonist of TLR9 and constitutively secrete type-I IFN but become progressively tolerant to further stimulation. By acute silencing of WASp and actin inhibitors, we show that WASp-mediated actin polymerization controls intracellular trafficking and compartmentalization of TLR9 ligands in pDCs restraining exaggerated activation of the TLR9-IFN-α pathway. Together, these data highlight the role of actin dynamics in pDC innate functions and imply the pDC-IFN-α axis as a player in the onset of autoimmune phenomena in WAS disease.

Original languageEnglish
Pages (from-to)355-374
Number of pages20
JournalJournal of Experimental Medicine
Issue number2
Publication statusPublished - Feb 2013

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy


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