Expression profile of proinflammatory genes in neutrophil-enriched granulocytes stimulated with native anti-PR3 autoantibodies.

Granulomatosis with polyangiitis (Wegener's ) is a rare autoimmune disease associated with the presence of antibodies directed against neutrophil antigen, proteinase-3 (PR3). The mechanisms by which anti-neutrophil cytoplasmic antibodies (ANCA) may activate neutrophils are still not well understood. In the present study we analyzed neutrophil gene expression profile after anti-PR3 antibodies stimulation. Briefly neutrophils isolated from 12 healthy volunteers, who tested negative for anti-PR3 autoantibodies, were stimulated with anti-PR3 IgG and activation of 147 genes was analyzed with the use of TaqMan low-density arrays. In stimulated neutrophils we observed up-regulation of 13 genes (CCL2, CXCL2, VCAM1, MMP9, PLCB4, PDE4C, PLA2G4C, RAC1, RHOA, IRAK1, CACNA1D, CACNB2, PTGDR), further 11 genes were up-regulated only in some donors (IL13, PF4, IL2RG, ITGB1, CD83, PLA2G7, ALOX12, AXNA1, AXNA5, LTA4H, MCR2) yet two others (HRH3 and PLA2G2D) were up-regulated in a few samples and undetectable in others. The obtained results demonstrate that c-ANCA mediated activation of neutrophils involve several pathways mediated via FcγRs like calcium signaling, phosphatidylinositol 3-kinase AKT pathway or MAPK signaling systems, but also inducts others, like G-protein signaling. Neutrophil is a very sensitive cell, responding to many environment changes. As our results showed, some anti-PR3 responses are highly variable across donors. Perhaps, this variablity also contribute to the susceptibility for granulocyte vasculitis and requires future studies.