Cognate Antigen-Independent Differentiation and Activation of Resident Memory T cells in Chronic Kidney Disease
Authors: Moore Kyle , Erman Elise , Traylor Amie , Esman Stephanie , Jiang Yanlin , LaFontaine Jennifer , Zmijewska Anna 
Published: May 2024

Resident memory T cells (TRMs) are a memory subset of T cells which are retained locally within barrier and epithelial tissues such as the kidney and have also been noted for their role in perpetuating chronic inflammation. While T cells have gained recognition for their ability to modulate kidney inflammation in various models of kidney injury TRMs are still poorly understood and their contributions to sterile models of chronic kidney disease (CKD) are unknown. We hypothesized that kidney TRMs are activated and modulate kidney inflammation in the setting of CKD. We utilized an aristolochic acid (AA) model of murine CKD to investigate the presence of kidney TRMs via flow cytometry and characterized their transcriptional profile via single cell RNA sequencing (scRNAseq). We also measured kidney cytokine levels with an MSD cytokine plate. Six weeks after AA-induced CKD, kidney CD8+ T cells were significantly increased compared to control mice (29.6 ± 1.6% vs. 4.7 ± 0.6% of CD45+, respectively; p<0.0001), as were CD4+ T cells (34.4 ± 1.4% vs. 8.2 ± 0.7% of CD45+, respectively; p<0.0001). 53.6 ± 2.5% of CD8+ T cells expressed CD103, a TRM marker, in AA mice compared to 4.8 ± 1.2% in control mice, and 36.0 ± 1.7% vs 1.6 ± 0.3% of CD4+ T cells. Kidney protein lysates of AA mice had significantly higher levels of IFNγ than control kidneys (18.9 ± 1.6 vs. 2.9 ± 0.7 pg/mg, respectively; p=0.0003) as well as TNF (98.6 ± 8.9 pg/mg vs. 6.9 ± 0.8 pg/mg, respectively; p=0.0002) and IL-6 (247.6 ± 39.1 pg/mg vs. 75.4 ± 22.5 pg/mg, respectively; p=0.0226). scRNAseq of immune cells revealed T cells bearing TRM markers CD103 and CD49a which lacked expression of tissue egress molecules S1pr1, Sell, Ccr7, and Klf2. scRNAseq analysis of this TRM population also revealed downregulation of Eomes and Tbx21 transcription factors and upregulation of Runx3 transcription factor, all of which correspond with previously described TRM transcriptional profiles. We next evaluated signaling pathways involved with the survival and transcriptional profile of TRMs, namely IL-15 and TGF-β. While Il2rb and Il2rg (encoding IL-15 receptor subunits) were upregulated in TRMs, IL-15 protein lysate levels were not elevated in AA kidneys compared to controls (2,600 ± 145 pg/mg protein vs. 2,281 ± 96 pg/mg protein, respectively; p=0.0831). Tgfbr1 and Tgfbr2 (encoding TGF-β receptor subunits) were also upregulated in TRMs, but TGF-β protein lysate levels were not significantly elevated in AA kidneys compared to controls (2,158 ± 159 pg/mg protein vs. 1,924 ± 202 pg/mg protein, respectively; p=0.3886). Gene ontology pathway analysis showed enrichment of pathways involved in T cell receptor signaling. Because of this we assessed the kidney immune profile of transgenic OT-1 mice, which can only recognize specific ovalbumin residues in the context of MHC class 1 H-2Kb. Six weeks after AA-induced CKD, injured OT-1 mice still had a significant increase in the proportion of CD8+ T cells that were CD103+ compared to vehicle control OT-1 mice (47.3 ± 2.9% vs. 9.6 ± 1.6% of CD45+, respectively; p<0.0001) and CD4+ T cells that were CD103+ (26.7 ± 3.1% vs. 6.4 ± 2.4% of CD45+, respectively; p=0.0040). Here we demonstrate the differentiation and activation of TRMs during AA-induced CKD independent of cognate antigen interaction and highlight their activated profile, as well as an increase in kidney IFNγ, TNF, and IL-6, all proinflammatory cytokines typical of TRMs. Future studies will aim to determine the contributions of TRMs to CKD progression. F32 DK136187, T32 DK007545, R01 DK 118932, U54 DK137301. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.