Peptidylarginine deiminase inhibition is immunomodulatory and vasculoprotective in murine lupus
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
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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Research Article Immunology

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 4

In vivo, Cl-amidine inhibits NET formation while altering complement levels and the autoantibody profile of NZM mice.

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In vivo, Cl-amidine inhibits NET formation while altering complement lev...
Female NZM mice were treated by daily subcutaneous injection with either Cl-amidine (10 mg/kg/d) or vehicle control beginning at 12 weeks of age (10 mice per group). Mice were sacrificed at 26 weeks of age. (A) Bone marrow neutrophils from sacrificed mice were incubated either in the absence of serum for 4 hours (no stim) or with 100 nM PMA for 12 hours. NET formation was quantified by fluorescence microscopy. (B–D) Serum from the aforementioned 2 groups was assayed for complement C3 (B), anti-dsDNA antibodies (C), or total IgG (D) using commercial kits. For C3, P values result from comparison to the baseline 12-week group. For anti-dsDNA, P values compare the vehicle and Cl-amidine groups directly. *P < 0.05; **P < 0.01; ***P < 0.001. For A, C, and D, data were plotted as the mean ± SEM. For B, boxes represent the median, 25th percentile, and 75th percentile, while whiskers delineate the minimum and maximum values.