The Wnt Antagonist Dickkopf-Promotes Pathological Type 2 Cell-Mediated Inflammation

Exposure to a plethora of environmental challenges commonly triggers pathological type 2 cell-mediated inflammation. Here we report the pathological role of the Wnt antagonist Dickkopf-(Dkk-1) upon allergen challenge or non-healing parasitic infection. The increased circulating amounts of Dkk-polarized T cells to T helper 2 (Th2) cells, stimulating a marked simultaneous induction of the transcription factors c-Maf and Gata-3, mediated by the kinases p38 MAPK and SGK-1, resulting in Th2 cell cytokine production. Circulating Dkk-was primarily from platelets, and the increase of Dkk-resulted in formation of leukocyte-platelet aggregates (LPA) that facilitated leukocyte infiltration to the affected tissue. Functional inhibition of Dkk-impaired Th2 cell cytokine production and leukocyte infiltration, protecting mice from house dust mite (HDM)-induced asthma or Leishmania major infection. These results highlight that Dkk-from thrombocytes is an important regulator of leukocyte infiltration and polarization of immune responses in pathological type 2 cell-mediated inflammation.