Kollareth Denny Joseph Manual, Leroy Victoria, Tu Zhenxiao, Woolet-Stockton Makena Jade, Kamat Manasi, Garrett Timothy J, Atkinson Carl, Cai Guoshuai, Upchurch Gilbert R, Sharma Ashish K
Department of Surgery, University of Florida, Gainesville, Florida, USA.
Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Florida, Gainesville, Florida, USA.
FASEB J. 2025 Apr 30;39(8):e70545. doi: 10.1096/fj.202401475R.
Post-lung transplant (LTx) injury can involve sterile inflammation due to ischemia-reperfusion injury (IRI) that contributes to allograft dysfunction. In this study, we investigated the cell-specific role of ferroptosis (excessive iron-mediated cell death) in mediating lung IRI and investigated if specialized pro-resolving mediators such as Lipoxin A4 (LxA) can protect against ferroptosis in lung IRI. Single-cell RNA sequencing analysis of lung tissue from post-LTx patients was performed, and lung IRI was evaluated in C57BL/6 (WT), formyl peptide receptor 2 knockout (Fpr2) and nuclear factor erythroid 2-related factor 2 knockout (Nrf2) mice using a hilar-ligation model with or without LxA administration. Furthermore, the protective efficacy of LxA was evaluated employing a murine orthotopic LTx model and in vitro studies using alveolar type II epithelial (ATII) cells. The results show differential expression of ferroptosis-related genes in post-LTx patient samples compared to healthy controls. A significant increase in the levels of oxidized lipids and a reduction in the levels of intact lipids were observed in mice subjected to IRI compared to shams. Importantly, LxA treatment attenuated pulmonary dysfunction, ferroptosis, and inflammation in WT mice subjected to lung IRI, but not in Fpr2 or Nrf2 mice after IRI. In the murine LTx model, LxA treatment increased PaO levels and attenuated lung IRI. Mechanistically, LxA-mediated protection involves an increase in NRF2 activation and glutathione concentration as well as a decrease in MDA levels in ATII cells. In summary, our results collectively show that LxA/FPR2 signaling on ATII cells mitigates ferroptosis via NRF2 activation and protects against lung IRI.
肺移植(LTx)后损伤可涉及由缺血再灌注损伤(IRI)引起的无菌性炎症,这会导致同种异体移植功能障碍。在本研究中,我们调查了铁死亡(过量铁介导的细胞死亡)在介导肺IRI中的细胞特异性作用,并研究了诸如脂氧素A4(LxA)等特殊的促消退介质是否能预防肺IRI中的铁死亡。我们对LTx后患者的肺组织进行了单细胞RNA测序分析,并使用肺门结扎模型,在给予或不给予LxA的情况下,对C57BL/6(野生型,WT)、甲酰肽受体2基因敲除(Fpr2)和核因子红细胞2相关因子2基因敲除(Nrf2)小鼠的肺IRI进行了评估。此外,我们使用小鼠原位LTx模型和体外肺泡II型上皮(ATII)细胞研究评估了LxA的保护效果。结果显示,与健康对照相比,LTx后患者样本中铁死亡相关基因的表达存在差异。与假手术组相比,IRI小鼠体内氧化脂质水平显著升高,完整脂质水平降低。重要的是,LxA治疗减轻了肺IRI野生型小鼠的肺功能障碍、铁死亡和炎症,但对IRI后的Fpr2或Nrf2小鼠无效。在小鼠LTx模型中,LxA治疗提高了动脉血氧分压(PaO)水平并减轻了肺IRI。从机制上讲,LxA介导的保护作用涉及ATII细胞中NRF2激活增加、谷胱甘肽浓度升高以及丙二醛(MDA)水平降低。总之,我们的结果共同表明,ATII细胞上的LxA/FPR2信号通过激活NRF2减轻铁死亡,并预防肺IRI。