Neutrophil surface presentation of the anti-neutrophil cytoplasmic antibody-antigen proteinase 3 depends on N-terminal processing

Abstract

SummaryThe neutrophil serine protease proteinase 3 (PR3) is a main autoantigen in anti-neutrophil cytoplasmic antibody-associated vasculitis. PR3 surface presentation on neutrophilic granulocytes, the main effector cells, is pathogenically important. PR3 is presented by the NB1 (CD177) glycoprotein, but how the presentation develops during neutrophil differentiation is not known. An N-terminally unprocessed PR3 (proPR3) is produced early during neutrophil development and promotes myeloid cell differentiation. We therefore investigated if PR3 presentation depended on NB1 during neutrophil differentiation and if PR3 and proPR3 could both be presented by NB1. In contrast to mature neutrophils, differentiating neutrophils showed an early NB1-independent PR3 surface display that was recognized by only two of four monoclonal anti-PR3 antibodies and occurred in parallel with proPR3, but not PR3 secretion, suggesting that the NB1-independent surface PR3 was proPR3. PR3 gene expression preceeded NB1. When the NB1 receptor was detected on the surface, a mode of PR3 surface display similar to mature neutrophils developed together with the degranulation system. Ectopic expression studies showed that NB1 was a sufficient receptor for PR3 but not proPR3. ProPR3 display on the plasma membrane may influence the bone marrow microenvironment. NB1-mediated PR3 presentation depended on PR3 N-terminal processing implicating the PR3-N-terminus as NB1-binding site.

Complement Receptor Mac-1 Is an Adaptor for NB1 (CD177)-mediated PR3-ANCA Neutrophil Activation

“…High mPR3 expression is only found on those neutrophils that co-express the GPI-linked NB1 receptor (17,18,20). We performed previously ectopic expression studies showing that NB1 was a sufficient receptor for PR3 (18,35). Korkmaz et al (19) elegantly showed that a hydrophobic patch of the PR3 molecule mediates membrane binding via NB1 receptors.…”

Translational Mini-Review Series on Immunology of Vascular Disease: Mechanisms of vascular inflammation and remodelling in systemic vasculitis

“…For proteinase 3, an individual, possibly genetically encoded, pattern regulates expression in the absence of detectable stimuli [4]. Membrane expression of proteinase 3 depends on mature neutrophils on the CD177 glycoprotein and on partial processing of the amino terminus of the molecule [51].…”

Neutrophil Elastase, Proteinase 3, and Cathepsin G as Therapeutic Targets in Human Diseases

“…NB1 shows a bimodal distribution that superimposes with that of PR3 on purified blood neutrophils (Bauer et al, 2007). Active, mature forms of PR3 but not pro-PR3 can bind to the surface of NB1-transfected human embryonic kidney 293 cells (von Vietinghoff et al, 2008) and Chinese hamster ovary cells (Korkmaz et al, 2008b). Interaction involves the hydrophobic patch of PR3 because specific amino acid substitutions disrupting this patch in the closely related gibbon PR3 prevent binding to NB1-transfected cells (Korkmaz et al, 2008b).…”