Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, WI, USA.
Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA; ReNeuroGen LLC, Milwaukee, WI, USA.
Free Radic Biol Med. 2021 Apr;166:73-89. doi: 10.1016/j.freeradbiomed.2021.02.006. Epub 2021 Feb 17.
Bronchopulmonary dysplasia (BPD) is caused primarily by oxidative stress and inflammation. To induce BPD, neonatal rat pups were raised in hyperoxic (>90% O) environments from day one (P1) until day ten (P10) and treated with N-acetyl-lysyltyrosylcysteine amide (KYC). In vivo studies showed that KYC improved lung complexity, reduced myeloperoxidase (MPO) positive (+) myeloid cell counts, MPO protein, chlorotyrosine formation, increased endothelial cell CD31 expression, decreased 8-OH-dG and Cox-1/Cox-2, HMGB1, RAGE, TLR4, increased weight gain and improved survival in hyperoxic pups. EPR studies confirmed that MPO reaction mixtures oxidized KYC to a KYC thiyl radical. Adding recombinant HMGB1 to the MPO reaction mixture containing KYC resulted in KYC thiylation of HMGB1. In rat lung microvascular endothelial cell (RLMVEC) cultures, KYC thiylation of RLMVEC proteins was increased the most in RLMVEC cultures treated with MPO + HO, followed by HO, and then KYC alone. KYC treatment of hyperoxic pups decreased total HMGB1 in lung lysates, increased KYC thiylation of HMGB1, terminal HMGB1 thiol oxidation, decreased HMGB1 association with TLR4 and RAGE, and shifted HMGB1 in lung lysates from a non-acetylated to a lysyl-acetylated isoform, suggesting that KYC reduced lung cell death and that recruited immune cells had become the primary source of HMGB1 released into the hyperoxic lungs. MPO-dependent and independent KYC-thiylation of Keap1 were both increased in RLMVEC cultures. Treating hyperoxic pups with KYC increased KYC thiylation and S-glutathionylation of Keap1, and Nrf2 activation. These data suggest that KYC is a novel system pharmacological agent that exploits MPO to inhibit toxic oxidant production and is oxidized into a thiyl radical that inactivates HMGB1, activates Nrf2, and increases antioxidant enzyme expression to improve lung complexity and reduce BPD in hyperoxic rat pups.
支气管肺发育不良（BPD）主要由氧化应激和炎症引起。为了诱导 BPD，新生大鼠在 P1 至 P10 期间在高氧（>90% O）环境中饲养，并接受 N-乙酰-赖氨酰-酪氨酸-半胱氨酸酰胺（KYC）治疗。体内研究表明，KYC 改善了肺复杂性，减少了髓过氧化物酶（MPO）阳性（+）髓样细胞计数、MPO 蛋白、氯酪氨酸形成，增加了内皮细胞 CD31 的表达，降低了 8-OH-dG 和 Cox-1/Cox-2、HMGB1、RAGE、TLR4，增加了高氧幼鼠的体重增加和存活率。EPR 研究证实，MPO 反应混合物将 KYC 氧化为 KYC 硫自由基。将重组 HMGB1 添加到包含 KYC 的 MPO 反应混合物中，导致 HMGB1 被 KYC 硫代。在大鼠肺微血管内皮细胞（RLMVEC）培养物中，在接受 MPO+HO 处理的 RLMVEC 培养物中，KYC 对 RLMVEC 蛋白的硫代化作用最大，其次是 HO，然后是单独的 KYC。KYC 处理高氧幼鼠降低了肺裂解物中的总 HMGB1，增加了 HMGB1 的 KYC 硫代化、末端 HMGB1 巯基氧化、HMGB1 与 TLR4 和 RAGE 的结合减少，并使肺裂解物中的 HMGB1 从非乙酰化转变为赖氨酸乙酰化同工型，表明 KYC 降低了肺细胞死亡，募集的免疫细胞已成为释放到高氧肺中的 HMGB1 的主要来源。RLMVEC 培养物中 Keap1 的 MPO 依赖性和非依赖性 KYC 硫代化均增加。用 KYC 处理高氧幼鼠增加了 Keap1 的 KYC 硫代化和 S-谷胱甘肽化以及 Nrf2 的激活。这些数据表明，KYC 是一种新型系统药理学药物，它利用 MPO 抑制有毒氧化剂的产生，并被氧化为一种硫自由基，该自由基使 HMGB1 失活，激活 Nrf2，并增加抗氧化酶的表达，从而改善肺复杂性并减少高氧大鼠幼鼠的 BPD。
