PAD4 is serially diluted in the presence of 10 nM GSK215 in assay buffer (100 mM HEPES, pH 8, 50 mM NaCl, 5% glycerol, 1 mM CHAPS, 1 mM DTT) at varying concentrations of calcium (0, 0.2, 2 and 10 mM). Following incubation for 50 min, apparent K_ds for each calcium concentration are determined using a single site saturation curve. For IC₅₀ determination, test compounds (e.g., GSK484) are serially diluted in DMSO (1% final assay concentration) and tested at the same range of calcium concentrations in the presence of PAD4 (at the calculated K_d for each calcium condition) and 10 nM GSK215 in the same assay buffer and volume. Reactions are incubated for 50 min after which IC₅₀ values are calculated using a four-parameter logistic equation^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

HEK293 cells stably expressing N-terminal FLAG-tagged PAD1, PAD2, PAD3 or PAD4 are engineered by retroviral transduction. Cells are grown in 15 cm diameter plates to subconfluency in DMEM supplemented with 10% Foetal Bovine Serum, harvested by centrifugation and washed once in PBS/2 mM EGTA. Cells are lysed in 50 mM Tris-Cl, pH 7.4, 1.5 mM MgCl₂, 5% glycerol, 150 mM NaCl, 25 mM NaF, 1 mM Na₃VO₄, 0.4% NP40, 1 mM DTT with protease inhibitors. Lysates are pre-incubated for 20 min at 4°C with DMSO alone (2%), 100 μM of GSK199, GSK484, GSK106 or 200 μM Cl-amidine. Citrullination reactions are performed for 30 min at 37°C in the presence of 2 mM calcium. Extracts are loaded on to gels, proteins separated by SDS-PAGE and transferred to PVDF membranes. Citrullinated proteins are then chemically modified and detected using anti-modified citrulline antibody. FLAG-PAD constructs are detected using anti-FLAG antibody^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Mice^[2]
The study includes two transgenic mouse models, the MMTV-PyMT mouse model for mammary carcinoma (FVB/n background) and the RIP1-Tag2 mouse model for pancreatic neuroendocrine carcinoma (C57BL/6 background). Mice are treated daily by intra-peritoneal injections of the PAD4 inhibitor GSK484 (4 mg/kg). GSK484 is dissolved in 99.9% ethanol at a concentration of 25 mg/mL to generate a stock solution and further diluted 1:50 in 0.9% NaCl shortly before injection of 200 μL/mouse^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Lewis HD, et al. Inhibition of PAD4 activity is sufficient to disrupt mouse and human NET formation. Nat Chem Biol. 2015 Mar;11(3):189-91.  [Content Brief]

  [2]. Cedervall J, et al. Pharmacological targeting of peptidylarginine deiminase 4 prevents cancer-associated kidney injury in mice. Oncoimmunology. 2017 Apr 20;6(8):e1320009.  [Content Brief]