Peptidylarginine deiminase inhibition is immunomodulatory and vasculoprotective in murine lupus
Jason S. Knight, … , Paul R. Thompson, Mariana J. Kaplan
Jason S. Knight, … , Paul R. Thompson, Mariana J. Kaplan
Published June 3, 2013
Citation Information: J Clin Invest. 2013;123(7):2981-2993. https://doi.org/10.1172/JCI67390.
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Peptidylarginine deiminase inhibition is immunomodulatory and vasculoprotective in murine lupus

Abstract

Recent evidence suggests that enhanced neutrophil extracellular trap (NET) formation activates plasmacytoid dendritic cells and serves as a source of autoantigens in SLE. We propose that aberrant NET formation is also linked to organ damage and to the premature vascular disease characteristic of human SLE. Here, we demonstrate enhanced NET formation in the New Zealand mixed 2328 (NZM) model of murine lupus. NZM mice also developed autoantibodies to NETs as well as the ortholog of human cathelicidin/LL37 (CRAMP), a molecule externalized in the NETs. NZM mice were treated with Cl-amidine, an inhibitor of peptidylarginine deiminases (PAD), to block NET formation and were evaluated for lupus-like disease activity, endothelial function, and prothrombotic phenotype. Cl-amidine treatment inhibited NZM NET formation in vivo and significantly altered circulating autoantibody profiles and complement levels while reducing glomerular IgG deposition. Further, Cl-amidine increased the differentiation capacity of bone marrow endothelial progenitor cells, improved endothelium-dependent vasorelaxation, and markedly delayed time to arterial thrombosis induced by photochemical injury. Overall, these findings suggest that PAD inhibition can modulate phenotypes crucial for lupus pathogenesis and disease activity and may represent an important strategy for mitigating cardiovascular risk in lupus patients.

Authors

Jason S. Knight, Wenpu Zhao, Wei Luo, Venkataraman Subramanian, Alexander A. O’Dell, Srilakshmi Yalavarthi, Jeffrey B. Hodgin, Daniel T. Eitzman, Paul R. Thompson, Mariana J. Kaplan

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Figure 2

NZM IgG binds to NETs and to proteins derived from NETs.

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NZM IgG binds to NETs and to proteins derived from NETs. (A) Paraformald...
(A) Paraformaldehyde-fixed NZM NETs were incubated with 1% serum from NZM (top panel) or BALB/c (bottom panel) mice more than 24 weeks old. Bound IgG was detected with Texas red–conjugated anti-mouse IgG. DNA is stained blue with Hoechst 33342. Original magnification, ×400. Scale bar: 50 microns. (B) Serum was tested for autoantibodies to NETs or CRAMP as described in Methods. OD index compares absorbance to the mean value for BALB/c controls. Each data point represents an individual mouse, with mean and SEM shown for each group. *P < 0.05. (C) NETs were generated as described in Methods. 20 μg of either NET protein or unstimulated neutrophil lysate (Lys) was resolved by 15% SDS-PAGE and probed with 0.5% NZM or BALB/c serum; bands were detected with HRP-conjugated anti-mouse IgG. Blots were also probed with anti-MPO to ensure equal loading. Data in A and C are representative of at least 3 independent experiments.