Institute of Immunology, Third Military Medical University (Army Medical University), Chongqing, China.
The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
Front Immunol. 2024 Oct 18;15:1405748. doi: 10.3389/fimmu.2024.1405748. eCollection 2024.
Kidney inflammation plays a crucial role in the pathogenesis of IgA nephropathy (IgAN), yet the specific phenotypes of immune cells involved in disease progression remain incompletely understood. Utilizing joint profiling through longitudinal single-cell RNA-sequencing (scRNAseq) and single-cell assay for transposase-accessible chromatin sequencing (scATACseq) can provide a comprehensive framework for elucidating the development of cell subset diversity and how chromatin accessibility regulates transcription.
We aimed to characterize the dynamic immune cellular landscape at a high resolution in an early IgAN mouse model with acute kidney injury (AKI).
A murine model was utilized to mimic 3 immunological states -"immune stability (IS), immune activation (IA) and immune remission (IR)" in early human IgAN-associated glomerulopathy during AKI, achieved through lipopolysaccharide (LPS) injection. Urinary albumin to creatinine ratio (UACR) was measured to further validate the exacerbation and resolution of kidney inflammation during this course. Paired scRNAseq and scATACseq analysis was performed on CD45 immune cells isolated from kidney tissues obtained from CTRL (healthy vehicle), IS, IA and IR (4 or 5 mice each). The analyses revealed 7 major cell types and 24 clusters based on 72304 single-cell transcriptomes, allowing for the identification and characterization of various immune cell types within each cluster. Our data offer an impartial depiction of the immunological characteristics, as the proportions of immune cell types fluctuated throughout different stages of the disease. Specifically, these analyses also revealed novel subpopulations, such as a macrophage subset (Nlrp1b Mac) with distinct epigenetic features and a unique transcription factor motif profile, potentially exerting immunoregulatory effects, as well as an early subset of Tex distinguished by their effector and cytolytic potential (CX3CR1transTeff). Furthermore, in order to investigate the potential interaction between immune cells and renal resident cells, we conducted single-cell RNA sequencing on kidney cells obtained from a separate cohort of IS and IA mice without isolating immune cells. These findings underscored the diverse roles played by macrophages and CD8 T cells in maintaining homeostasis of endothelial cells (ECs) under stress.
This study presents a comprehensive analysis of the dynamic changes in immune cell profiles in a model of IgAN, identifying key cell types and their roles and interactions. These findings significantly contribute to the understanding of the pathogenesis of IgAN and may provide potential targets for therapeutic intervention.
肾脏炎症在 IgA 肾病（IgAN）的发病机制中起着关键作用，但涉及疾病进展的免疫细胞的具体表型仍不完全清楚。通过纵向单细胞 RNA 测序（scRNAseq）和单细胞转座酶可及染色质测序（scATACseq）的联合分析，可以提供一个全面的框架来阐明细胞亚群多样性的发展以及染色质可及性如何调节转录。
我们旨在通过急性肾损伤（AKI）的早期 IgAN 小鼠模型以高分辨率描绘动态免疫细胞景观。
利用脂多糖（LPS）注射模拟了 3 种免疫状态-“免疫稳定（IS）、免疫激活（IA）和免疫缓解（IR）”，在早期人类 IgAN 相关肾小球病中的 AKI 中，建立了一种小鼠模型。通过测量尿白蛋白与肌酐比值（UACR）进一步验证了在此过程中肾脏炎症的加剧和缓解。对来自 CTRL（健康对照）、IS、IA 和 IR（每组 4 或 5 只小鼠）的肾组织中分离的 CD45 免疫细胞进行 scRNAseq 和 scATACseq 联合分析。分析基于 72304 个单细胞转录组，揭示了 7 种主要细胞类型和 24 个簇，从而能够鉴定和描述每个簇中的各种免疫细胞类型。我们的数据提供了免疫特征的公正描述，因为免疫细胞类型的比例在疾病的不同阶段波动。具体而言，这些分析还揭示了新的亚群，例如具有独特表观遗传特征和独特转录因子基序谱的巨噬细胞亚群（Nlrp1b Mac），可能发挥免疫调节作用，以及以其效应子和细胞毒性潜力为特征的早期 Tex 亚群（CX3CR1transTeff）。此外，为了研究免疫细胞与肾脏固有细胞之间的潜在相互作用，我们对来自另一批 IS 和 IA 小鼠的肾脏细胞进行了单细胞 RNA 测序，而无需分离免疫细胞。这些发现强调了巨噬细胞和 CD8 T 细胞在维持内皮细胞（ECs）应激下的稳态中的多种作用。
本研究全面分析了 IgAN 模型中免疫细胞谱的动态变化，确定了关键的细胞类型及其作用和相互作用。这些发现为 IgAN 的发病机制提供了重要的认识，并可能为治疗干预提供潜在的靶点。
