Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children's at Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Clin Exp Immunol. 2024 Nov 12;218(3):314-328. doi: 10.1093/cei/uxae080.
Kawasaki disease (KD) is the leading cause of acquired heart disease in children. While circulating neutrophils are increased and activated during acute KD, it is unclear whether neutrophils and neutrophil extracellular traps (NETs) contribute to the pathogenesis of KD. Peptidylarginine deiminase 4 (PAD4), an enzyme involved in protein citrullination and essential for NETs formation, is implicated in the pathogenesis of various diseases. Here, we used the Lactobacillus casei cell wall extract (LCWE)-induced mouse model of KD vasculitis to determine the contribution of PAD4 in KD vasculitis. We found that the pan-PADs inhibitor, Cl-amidine, significantly reduced LCWE-induced cardiovascular lesions, but neutrophil-specific Padi4 KO mice did not impact the development of KD vasculitis. While in vitro treatment of macrophages, which highly express Padi4, with Cl-amidine inhibited IL-1β secretion, macrophage-specific Padi4 KO mice did not reduce the lesions. Padi4-/- mice also developed KD vasculitis, AFM30a, a PAD2 inhibitor, significantly reduced KD vasculitis in Padi4-/- mice, indicating a compensatory role of PAD2 in PAD4 deficiency. We also identified several citrullinated proteins in macrophages with constitutively active NLRP3 inflammasome that were inhibited by Cl-amidine treatment, suggesting that protein citrullination participates in NLRP3 inflammasome activation. These data indicate a dispensable role for PAD4-dependent NETs formation, and a redundant role of PAD2 and PAD4 in this murine KD vasculitis. The cardioprotective effects of Cl-amidine to reduce the severity of murine KD vasculitis are not limited to PAD4 inhibition and may include decreased citrullination in the inflammasome pathway.
川崎病（KD）是儿童获得性心脏病的主要原因。虽然在急性 KD 期间循环中性粒细胞增加并被激活，但尚不清楚中性粒细胞和中性粒细胞胞外陷阱（NETs）是否有助于 KD 的发病机制。肽基精氨酸脱亚氨酶 4（PAD4）是一种参与蛋白质瓜氨酸化并对 NETs 形成至关重要的酶，与各种疾病的发病机制有关。在这里，我们使用干酪乳杆菌细胞壁提取物（LCWE）诱导的 KD 血管炎小鼠模型来确定 PAD4 在 KD 血管炎中的作用。我们发现，泛 PADs 抑制剂 Cl-amidine 可显著减轻 LCWE 诱导的心血管病变，但中性粒细胞特异性 Padi4 KO 小鼠对 KD 血管炎的发展没有影响。虽然体外用高表达 Padi4 的巨噬细胞处理 Cl-amidine 抑制了 IL-1β 的分泌，但巨噬细胞特异性 Padi4 KO 小鼠并未减少病变。Padi4-/- 小鼠也发生了 KD 血管炎，PAD2 抑制剂 AFM30a 显著减轻了 Padi4-/- 小鼠的 KD 血管炎，表明 PAD2 在 PAD4 缺乏时起代偿作用。我们还鉴定了具有组成性激活 NLRP3 炎性体的巨噬细胞中的几种瓜氨酸化蛋白，Cl-amidine 处理可抑制这些蛋白，表明蛋白质瓜氨酸化参与 NLRP3 炎性体的激活。这些数据表明 PAD4 依赖性 NETs 形成的作用不大，PAD2 和 PAD4 在这种小鼠 KD 血管炎中具有冗余作用。Cl-amidine 降低严重程度的心脏保护作用不仅仅局限于 PAD4 抑制，还可能包括减少炎性体途径中的瓜氨酸化。
