Time restricted feeding reduces kidney CD8⁺T cell pathogenicity in diet-induced obesity

Obesity is a major risk factor for chronic diseases, especially chronic kidney disease. Time restricted feeding (TRF) may improve kidney health in obese individuals. Our lab previously reported that 2-weeks of TRF (12-hour feeding period only during dark phase) at the end of a 20-week diet-induced obesity (DIO, 45% high fat diet) male mouse model significantly reduced renal interstitial fibrosis and improved tubular brush border integrity. TRF does not change food intake, body weight, or kidney weight in DIO mice. Interestingly, further studies found that CD8 + T cells (CD8Ts) are significantly increased in kidneys of DIO mice fed ad libitum compared to normal diet (ND, 10% fat) mice fed ad libitum. TRF in DIO mice significantly reduced renal CD8Ts compared to DIO restoring renal CD8Ts to that observed in ND mice (One-way ANOVA, p=0.0003, ND vs DIO: p=0.0002, DIO vs DIO+TRF: p=0.014). Anti-CD8 treatment during the final 2 weeks of DIO significantly reduced renal interstitial fibrosis and tubular brush border integrity compared to DIO control anti-IgG treated mice (Interstitial fibrosis: One-way ANOVA, p=0.003, ND anti-IgG vs DIO anti-IgG: p=0.003, DIO anti-IgG vs DIO anti-CD8: p=0.025; Brush border integrity: One-way ANOVA, p<0.0001, ND anti-IgG vs DIO anti-IgG: p<0.0001, DIO anti-IgG vs DIO anti-CD8: p<0.0001), indicating that CD8Ts mediate these measures of kidney damage in DIO. However, it is unclear whether the CD8Ts and/or surrounding adipose tissue are pro-inflammatory and cytotoxic in DIO. We hypothesized that DIO specifically increases pro-inflammatory and cytotoxic CD8Ts in the kidney, perirenal adipose tissue (PRAT), and mesenteric adipose tissue (MAT). Increased CD8T Granzyme B has been implicated in disease progression and fibrosis, making it a marker of interest. We found significantly increased Granzyme B CD8Ts in kidneys, PRAT, and MAT in DIO compared to ND mice that was significantly reduced with DIO+TRF (Kidney: One-way ANOVA: p=0.007, ND vs DIO: p=0.009, DIO vs DIO+TRF p=0.034; PRAT: One-way ANOVA: p=0.0121, DIO vs DIO+TRF: p=0.0157; MAT: One-way ANOVA, p=0.021, ND vs DIO: p=0.037, DIO vs DIO+TRF: p=0.032). Also, we used scRNAseq to identify specific pathways that may be altered with DIO and TRF in the kidneys. Total immune (CD45 + ) cells were sorted from kidneys of the three mouse groups (ND, DIO, and DIO+TRF) and processed for scRNAseq determinations. We identified CD8Ts from all three groups via Seurat. CD8Ts had 162 differentially expressed genes (DEGs) in ND vs DIO and 86 DEGs in DIO vs DIO+TRF. Myeloid cells had 50 DEGs and CD4Ts and B cells had less than 10 DEGs, further highlighting the importance of CD8Ts in our model. Several genes associated with T cell exhaustion ( Pdcd1, Maf, Havcr2, Cd200r1 ) were upregulated in CD8Ts from DIO compared to ND and DIO+TRF (Bonferroni adjusted p-value < 0.05 and log 2 fold change (FC) > 0.7 in all cases). We also found that the pro-fibrotic gene, Slamf1, is upregulated in CD8Ts in DIO compared to both ND and TRF (Bonferroni adjusted p-value < 0.05 and log 2 FC > 0.7). We conclude that TRF in DIO reduces pathogenic CD8Ts indicating an intervention to mitigate kidney damage in DIO. Further studies will investigate how specific CD8T exhaustion and cytotoxicity pathways in DIO mediate renal damage. NIH R01: 1R01DK134562-01A1 NIH F31: F31HL167626 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.