Background/Purpose: Lupus nephritis is a complex and heterogeneous disease characterized by infiltrating immune cells in damaged kidney tissue. While mouse models have enabled mechanistic studies of lupus nephritis, immune and kidney cell types and states are incompletely characterized. Thus, shared cells and pathways between mouse and human lupus nephritis remain unrecognized and could provide the basis for targeted studies as well as engineering existing mouse models to better reflect human disease. To provide a comprehensive view of active leukocytes in a common model of mouse lupus nephritis, NZB/W, we measured the transcriptomes of single cells from murine kidneys and as well as spleens at early and late stages of kidney disease.

Methods: NZB/W female mice were generated and followed clinically. Kidneys and spleens from NZB/W mice were harvested for analysis from two 22-week-old non-proteinuric and two 37-week-old proteinuric mice. Single immune and parenchymal cells from digested kidney, and immune cells from spleen, were collected by flow cytometric cell sorting. We used the 10X Chromium 5’ kit for single-cell encapsulation into droplets for library generation and next-generation sequencing for ~50,000 reads per cell. After normalization, single-cell transcriptomes passing quality metrics ( >500 genes and < 25% mitochondrial content) were analyzed with unsupervised clustering (Seurat 3.0).

Results: We profiled 32,969 single cells collected from kidneys and spleens from NZB/W lupus mice at early and late stages of kidney disease (pre- and proteinuric, 2 mice per disease stage). Using unsupervised transcriptome analysis we discovered 27 distinct cellular clusters. Of these, 15 were immune cell clusters reflecting distinct subsets of T, B, and myeloid cells in both damaged kidney tissue and the spleen; the remaining 12 cell clusters were non-hematopoietic cells reflecting kidney cell types and states in early and late stages of kidney disease. Comparing cells from the same organ type (kidney or spleen) harvested from different mice at identical disease stages revealed highly similar immune and non-hematopoietic cell clusters, indicating reproducibility across animals and minimal batch effect.

Conclusion: By measuring the transcriptomes from single cells collected from damaged murine kidney tissue and spleens at early and late stages of kidney disease (pre-proteinuric and proteinuric), this study provides a comprehensive view of active leukocytes of lupus nephritis in a common model, NZB/W. We discovered 27 distinct murine cellular clusters reflecting multiple T, B, and myeloid cell subsets, as well as non-hematopoietic kidney cells types. We will compare NZB/W immune and kidney cellular clusters to those recently discovered in human lupus nephritis patients by single cell transcriptome profiling (Arazi et. al, Nature Immunology, 2019; Der et. al. Nature Immunology, 2019). We expect to identify new and better understand existing cells and pathways shared between human mouse lupus nephritis. We anticipate this approach can incorporate other common mouse models of lupus nephritis to better understand how each is related to human disease.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-single-cell-transcriptomic-landscape-of-nzb-w-murine-lupus-at-early-and-late-stages-of-disease/