Immune Checkpoint Molecule TIGIT Modulates Kidney T Cell Glucose Uptake and Energetics at Baseline and After AKI

Background: Prior data demonstrated increased T cell immunoreceptor with Ig and ITIM domains (TIGIT) on kidney T cells following ischemia reperfusion (IR)-AKI (Noel et al, J Am Soc Nephrol, 2023). Additionally, TIGIT knockout (KO) mice had reduced kidney IR injury and increased T cell glucose transporter 1 (GLUT1) expression compared to wild-type (WT) mice. We hypothesized that TIGIT regulates kidney T cell glucose uptake and energetics during AKI Methods: CD3+T cells from kidneys of WT and TIGIT KO mice were cultured under normal or CoCl2 (200µM) induced hypoxic conditions. Moreover, kidney T cells were cultured with isotype or TIGIT blocking antibody, 1G9 (25µg/ml). WT and KO mice underwent bilateral kidney IR injury to induce AKI, then CD3+ T cells were isolated 24h post IR. Glucose uptake, oxygen consumption rate (OCR), extracellular acidification rate (ECAR), maximal respiration, spare respiratory capacity (SRC), and mitochondrial ATP production were assessed Results: TIGIT KO kidney T cells had increased glucose uptake compared to WT cells (4831±684 vs 2361±336RLU; P<0.05). Moreover, TIGIT blockade with 1G9 increased glucose uptake compared to untreated WT T cells (15148±2376 vs 4711±1390RLU; P<0.05). Under normal culture conditions, KO T cells exhibited higher basal OCR (26.2±0.03 vs 19.3±1.0pmol/min, P<0.001) and mitochondrial ATP production (83.7±6.4 vs 67.7±8.8pmol/min, P=0.06) compared to WT cells. Under chemical hypoxia, KO T cells had higher OCR (22.5±1.6 vs 16.2±0.7pmol/min, P<0.05) compared to WT cells. KO kidney T cells had higher glucose uptake at baseline (689.1±84.1 vs 262.8±25.6RLU; P<0.01) and post-IR (3478.3±479.5 vs 2002.3±324.3RLU; P<0.001) compared to WT cells. At baseline, T cells from KO mice had higher OCR (10.4±3.4 vs 4.1±0.4pmol/min, P<0.001), ECAR (1.3±0.4 vs 0.5±0.1mpH/min, P<0.01) and mitochondrial ATP production (14.2±4.5 vs 4.9±0.8pmol/min, P<0.01) compared to WT mice. Post-IR, KO T cells exhibited elevated OCR (6.34±1.8 vs 1.5±1.09pmol/min, P<0.01) and SRC (12.0±3.4 vs 3.1±1.5pmol/min, P<0.01) Conclusion: Both TIGIT genetic deletion and antibody blockade increased glucose uptake and modulated kidney T cell bioenergetics during in vitro hypoxia and AKI. T cell metabolic reprograming via TIGIT targeting could be a potential therapeutic approach for AKI Funding: NIDDK Support