GSK199 (hydrochloride)

GSK199 (hydrochloride) is an orally active and reversible selective peptidyl arginine deiminase 4 (PAD4) inhibitor with an IC₅₀ value of 200nM in the absence of calcium ions^[1]. PAD4 is an enzyme that converts arginine residues in proteins to citrulline residues and can trigger a series of chain reactions (such as inducing neutrophil extracellular trap formation)^[2]. GSK199 (hydrochloride) is commonly used in research on diseases such as rheumatoid arthritis, systemic lupus erythematosus, and vasculitis^[3,4].

In vitro, treatment of recombinant human PAD4 enzyme with GSK199 (hydrochloride) (8, 32, 128μM) for 2h significantly inhibited PAD4-mediated citrullination of fibrinogen, with an inhibition rate exceeding 90%^[5]. Pretreatment of fibroblast-like synoviocytes (FLS) isolated from the synovium of rheumatoid arthritis patients with GSK199 (hydrochloride) (10μM) for 72h completely blocked anti-citrullinated protein/peptide antibody (ACPAs)-induced FLS migration^[6].

In vivo, in a collagen-induced arthritis model in DBA/1J mice, subcutaneous administration of GSK199 (hydrochloride) (30mg/kg; once daily) starting from the day of immunization (day 0) for 35 days significantly improved histopathological scores of synovial inflammation, pannus formation, and cartilage damage. At this dose, it also significantly reduced complement C3 deposition in the synovium and cartilage of mouse joints. Administration of GSK199 (hydrochloride) at 30mg/kg twice daily almost completely eliminated C3 deposition^[7]. In a mouse model of inferior vena cava (IVC) ligation, a single dose of GSK199 (hydrochloride) (30mg/kg) administered via the tail vein 30min before ligation reversed the prothrombotic effect of platelet high mobility group box 1 (HMGB1)^[8].

References:
[1] LEWIS H D, LIDDLE J, COOTE J E, et al. Inhibition of PAD4 activity is sufficient to disrupt mouse and human NET formation[J]. Nature Chemical Biology, 2015, 11(3): 189-191.
[2] ROHRBACH A S, SLADE D J, THOMPSON P R, et al. Activation of PAD4 in NET formation[J]. Frontiers in Immunology, 2012, 3: 360.
[3] KOUSHIK S, JOSHI N, NAGARAJU S, et al. PAD4: pathophysiology, current therapeutics and future perspective in rheumatoid arthritis[J]. Expert Opinion on Therapeutic Targets, 2017, 21(4): 433-447.
[4] GAJENDRAN C, FUKUI S, SADHU N M, et al. Alleviation of arthritis through prevention of neutrophil extracellular traps by an orally available inhibitor of protein arginine deiminase 4[J]. Scientific Reports, 2023, 13(1): 3189.
[5] MARTÍN MONREAL M T, REBAK A S, MASSARENTI L, et al. Applicability of small-molecule inhibitors in the study of peptidyl arginine deiminase 2 (PAD2) and PAD4[J]. Frontiers in Immunology, 2021, 12: 716250.
[6] SUN M, RETHI B, KRISHNAMURTHY A, et al. Anticitrullinated protein antibodies facilitate migration of synovial tissue-derived fibroblasts[J]. Annals of the Rheumatic Diseases, 2019, 78(12): 1621-1631.
[7] WILLIS V C, BANDA N K, CORDOVA K N, et al. Protein arginine deiminase 4 inhibition is sufficient for the amelioration of collagen-induced arthritis[J]. Clinical and Experimental Immunology, 2017, 188(2): 263-274.
[8] DYER M R, CHEN Q, HALDEMAN S, et al. Deep vein thrombosis in mice is regulated by platelet HMGB1 through release of neutrophil-extracellular traps and DNA[J]. Scientific Reports, 2018, 8(1): 2068.

GSK199 (hydrochloride)是一种具有口服活性和可逆性的选择性肽基精氨酸脱亚氨酶4（PAD4）抑制剂，在缺少钙离子情况下IC₅₀值为200nM^[1]。PAD4是一种能将蛋白质中的精氨酸残基转化为瓜氨酸残基的酶，并可引发一系列连锁反应（如触发中性粒细胞胞外陷阱形成等）^[2]。GSK199 (hydrochloride)通常用于类风湿性关节炎、系统性红斑狼疮和血管炎等疾病的研究^[3,4]。

在体外，GSK199 (hydrochloride)（8, 32, 128μM）处理重组人PAD4酶2h，显著抑制了PAD4介导的纤维蛋白原瓜氨酸化，抑制率超过90%^[5]。GSK199 (hydrochloride)（10μM）预处理从类风湿关节炎患者滑膜分离的成纤维样滑膜细胞（FLS）72h，完全阻断了由抗瓜氨酸化蛋白/肽抗体（ACPAs）诱导的FLS迁移^[6]。

在体内，GSK199 (hydrochloride)（30mg/kg; once daily）从免疫当天（第0天）开始每日皮下给药治疗胶原诱导性关节炎DBA/1J小鼠35天，显著改善了小鼠滑膜炎症、血管翳形成和软骨损伤的组织病理学评分。在该剂量下还显著降低了小鼠关节滑膜和软骨中补体C3的沉积，按30mg/kg每日2次剂量给药小鼠后可几乎完全消除C3沉积^[7]。GSK199 (hydrochloride)（30mg/kg）通过尾静脉在下腔静脉（IVC）结扎前30min单次给药小鼠，逆转了血小板高迁移率族蛋白B1（HMGB1）的促血栓效应^[8]。