Ye Zhi-Wei, Zhang Jie, Kumar Amit, Huang Xuejian, Mathuram Theodore L, Mccall Andrew D, Culpepper John, Zhang Leilei, Curione Anthony D, Xu Jianqiang, Tew Kenneth D, Townsend Danyelle M, Blumental-Perry Anna
Department of Pharmacology and Immunology, College of Medicine, Medical University of South Carolina, Charleston, SC29425, USA.
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, NY14203, USA.
Redox Biol. 2025 May 27;85:103680. doi: 10.1016/j.redox.2025.103680.
Identifying factors that contribute to the age-related onset of chronic obstructive pulmonary disease (COPD) is crucial for its prevention and treatment. The multifunctional endoplasmic reticulum (ER) chaperone protein disulfide isomerase A1 (PDIA1) shows a protective increase in expression levels in human and mouse non-COPD smokers. However, this increase slows with aging and disease progression, while increase in glutathione S-transferase π1 (GSTP1) does not. PDI has redox sensitive cysteine residues that can become S-glutathionylated (PDI-SSG) which compromise both isomerase and chaperone activity. Oxidized PDIA1 levels progressively rise with age in the lungs of murine non-smokers, with an even greater increase in smokers. To investigate whether an increased oxidized-to-native PDIA1 ratio (PDI-SSG/PDI-SH) contributes to the depletion of alveolar epithelial type 2 progenitor cells in COPD, we used the type-2-like cell line MLE12. High doses of cigarette smoke (CS) induced elevated oxidized PDIA1 levels, while a redox-refractory PDIA1 variant maintained a lower PDI-SSG/PDI-SH. Upon CS exposure, PDIA1 was S-glutathionylated by GSTP1 and predominantly localized at the ER-mitochondria interface. This mitochondrial proximity was prevented by pharmacological or genetic GSTP1 inhibition. When localized at the ER-mitochondria interface, S-glutathionylated PDIA1 decreased mitochondrial membrane potential (MMP), facilitated mitochondrial permeability transition pore opening, decreased mitochondrial respiration and triggered cytochrome c (Cyt c) release, followed by caspase-3 activation. Isolated mitochondrial studies confirmed that PDI-SSG trigger these apoptotic signals whereas native PDI does not. Our findings indicate that GSTP1-mediated S-glutathionylation of PDIA1 drives pro-apoptotic intraorganellar signaling by altering its ER distribution. Overexpression of a redox-refractory PDIA1 variant restored MMP and reduced Cyt c release, suggesting that a lower S-glutathionylated-to-native PDIA1 ratio is protective. These findings highlight a threshold-dependent regulation of PDIA1-SSG/PDIA1-SH redox signaling. We propose that the simultaneous inability to maintain high PDIA1 levels and the age-associated increase in its S-glutathionylated form in smokers accelerates AEC2 depletion and exhaustion, thereby contributing to emphysema progression.
确定导致慢性阻塞性肺疾病（COPD）与年龄相关发病的因素对其预防和治疗至关重要。多功能内质网（ER）伴侣蛋白二硫键异构酶A1（PDIA1）在人类和小鼠非COPD吸烟者中表达水平呈保护性增加。然而，随着年龄增长和疾病进展，这种增加会减缓，而谷胱甘肽S-转移酶π1（GSTP1）的增加则不会。PDI具有氧化还原敏感的半胱氨酸残基，可被S-谷胱甘肽化（PDI-SSG），这会损害异构酶和伴侣活性。在小鼠非吸烟者的肺中，氧化型PDIA1水平随年龄逐渐升高，吸烟者中升高更为明显。为了研究氧化型与天然型PDIA1比例增加（PDI-SSG/PDI-SH）是否导致COPD中肺泡Ⅱ型祖细胞的耗竭，我们使用了Ⅱ型样细胞系MLE12。高剂量香烟烟雾（CS）诱导氧化型PDIA1水平升高，而氧化还原难治性PDIA1变体维持较低的PDI-SSG/PDI-SH。暴露于CS后，PDIA1被GSTP1 S-谷胱甘肽化，并主要定位于内质网-线粒体界面。药理学或基因抑制GSTP1可阻止这种线粒体接近。当定位于内质网-线粒体界面时，S-谷胱甘肽化的PDIA1降低线粒体膜电位（MMP），促进线粒体通透性转换孔开放，降低线粒体呼吸并触发细胞色素c（Cyt c）释放，随后激活caspase-3。分离线粒体研究证实，PDI-SSG触发这些凋亡信号，而天然型PDI则不会。我们的研究结果表明，GSTP1介导的PDIA1 S-谷胱甘肽化通过改变其在内质网的分布驱动促凋亡的细胞器内信号传导。氧化还原难治性PDIA1变体的过表达恢复了MMP并减少了Cyt c释放，表明较低的S-谷胱甘肽化与天然型PDIA1比例具有保护作用。这些发现突出了PDIA1-SSG/PDIA1-SH氧化还原信号的阈值依赖性调节。我们提出，吸烟者同时无法维持高PDIA1水平及其S-谷胱甘肽化形式的年龄相关增加会加速AEC2耗竭和衰竭，从而导致肺气肿进展。
