School of Clinical Medicine, Hebei University, Affiliated Hospital of Hebei University, Baoding, China.
Hebei Provincial Key Laboratory of Skeletal Metabolic Physiology of Chronic Kidney Disease, Affiliated Hospital of Hebei University, Baoding, China.
Front Immunol. 2024 Jan 26;15:1247382. doi: 10.3389/fimmu.2024.1247382. eCollection 2024.
The pathogenesis of renal fibrosis (RF) involves intricate interactions between profibrotic processes and immune responses. This study aimed to explore the potential involvement of the pyroptosis signaling pathway in immune microenvironment regulation within the context of RF. Through comprehensive bioinformatics analysis and experimental validation, we investigated the influence of pyroptosis on the immune landscape in RF.
We obtained RNA-seq datasets from Gene Expression Omnibus (GEO) databases and identified Pyroptosis-Associated Regulators (PARs) through literature reviews. Systematic evaluation of alterations in 27 PARs was performed in RF and normal kidney samples, followed by relevant functional analyses. Unsupervised cluster analysis revealed distinct pyroptosis modification patterns. Using single-sample gene set enrichment analysis (ssGSEA), we examined the correlation between pyroptosis and immune infiltration. Hub regulators were identified weighted gene coexpression network analysis (WGCNA) and further validated in a single-cell RNA-seq dataset. We also established a unilateral ureteral obstruction-induced RF mouse model to verify the expression of key regulators at the mRNA and protein levels.
Our comprehensive analysis revealed altered expression of 19 PARs in RF samples compared to normal samples. Five hub regulators, namely PYCARD, CASP1, AIM2, NOD2, and CASP9, exhibited potential as biomarkers for RF. Based on these regulators, a classifier capable of distinguishing normal samples from RF samples was developed. Furthermore, we identified correlations between immune features and PARs expression, with PYCARD positively associated with regulatory T cells abundance in fibrotic tissues. Unsupervised clustering of RF samples yielded two distinct subtypes (Subtype A and Subtype B), with Subtype B characterized by active immune responses against RF. Subsequent WGCNA analysis identified PYCARD, CASP1, and NOD2 as hub PARs in the pyroptosis modification patterns. Single-cell level validation confirmed PYCARD expression in myofibroblasts, implicating its significance in the stress response of myofibroblasts to injury. experimental validation further demonstrated elevated PYCARD expression in RF, accompanied by infiltration of Foxp3 regulatory T cells.
Our findings suggest that pyroptosis plays a pivotal role in orchestrating the immune microenvironment of RF. This study provides valuable insights into the pathogenesis of RF and highlights potential targets for future therapeutic interventions.
肾纤维化（RF）的发病机制涉及到致纤维化过程和免疫反应之间复杂的相互作用。本研究旨在探讨细胞焦亡信号通路在 RF 免疫微环境调节中的潜在作用。通过全面的生物信息学分析和实验验证，我们研究了细胞焦亡对 RF 中免疫景观的影响。
我们从基因表达综合（GEO）数据库中获取了 RNA-seq 数据集，并通过文献回顾确定了细胞焦亡相关调节剂（PARs）。系统评估了 RF 和正常肾脏样本中 27 个 PAR 的改变，随后进行了相关功能分析。无监督聚类分析揭示了明显的细胞焦亡修饰模式。使用单样本基因集富集分析（ssGSEA），我们研究了细胞焦亡与免疫浸润之间的相关性。通过加权基因共表达网络分析（WGCNA）确定了关键调节剂，并在单细胞 RNA-seq 数据集上进行了进一步验证。我们还建立了单侧输尿管梗阻诱导的 RF 小鼠模型，以验证关键调节剂在 mRNA 和蛋白质水平上的表达。
我们的综合分析显示，与正常样本相比，RF 样本中 19 个 PAR 的表达发生了改变。五个关键调节剂，即 PYCARD、CASP1、AIM2、NOD2 和 CASP9，具有作为 RF 生物标志物的潜力。基于这些调节剂，我们开发了一个能够区分正常样本和 RF 样本的分类器。此外，我们还发现了免疫特征与 PARs 表达之间的相关性，其中 PYCARD 与纤维化组织中调节性 T 细胞的丰度呈正相关。RF 样本的无监督聚类产生了两个不同的亚型（亚型 A 和亚型 B），其中亚型 B 的特点是对 RF 有活跃的免疫反应。随后的 WGCNA 分析确定了 PYCARD、CASP1 和 NOD2 作为细胞焦亡修饰模式中的关键 PAR。单细胞水平验证证实了 PYCARD 在肌成纤维细胞中的表达，提示其在肌成纤维细胞对损伤的应激反应中的重要性。实验验证进一步表明，RF 中 PYCARD 的表达升高，同时 Foxp3 调节性 T 细胞浸润。
我们的研究结果表明，细胞焦亡在调控 RF 的免疫微环境中起着关键作用。本研究为 RF 的发病机制提供了有价值的见解，并强调了未来治疗干预的潜在靶点。
