Transcriptional signature pinpoints metabolic and signaling changes associated with exhaustion in T cells along CLL progression. (A) Heat map of differentially expressed genes in various activation and metabolic signaling pathways in intermediate (interm)- and late-stage AT Eμ-TCL1 CD8⁺ T cells compared with WT (the 2 columns in each condition represent duplicate runs). (B) Volcano plot showing significantly upregulated (red) or downregulated (blue) genes in late- vs interm-stage AT Eμ-TCL1 CD8⁺ T cells, alongside differentially regulated pathways based on directed global gene set analysis significance score provided by ROSALIND software. Labeled genes on the volcano plot are related to either glycolysis, mitochondrial respiration, amino acid transporters, autophagy, AMPK pathway, cytokine and chemokine signaling, or TCR and costimulatory signaling. (C) Representative protein immunoblot analysis of selected targets related to AMPK pathway and mitochondrial dynamics in CD8⁺ T cells isolated from WT or AT Eμ-TCL1 mice at different disease stages. (D) Quantitative results comparing the expression of selected proteins in late- vs interm-stage CD8⁺ T cells. Isolated CD8⁺ T cells in each individual sample were pooled from ≥3 different mice spleens. Significance calculated as a P value <.05 and fold change ≥1.5 (upregulation) or –1.5 or less (downregulation) in panels A-B. Differences analyzed using 2-tailed, unpaired t test in panel D. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001.