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Kidney Week

Abstract: PO0658

Twist1 in T Lymphocytes Exaggerates Kidney Fibrosis After Ureteral Obstruction

Session Information

  • CKD Mechanisms - 2
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2103 CKD (Non-Dialysis): Mechanisms

Authors

  • Ren, Jiafa, Duke University School of Medicine, Durham, North Carolina, United States
  • Privratsky, Jamie, Duke University School of Medicine, Durham, North Carolina, United States
  • Crowley, Steven D., Duke University School of Medicine, Durham, North Carolina, United States
Background

T cells play a critical role in directing kidney fibrogenesis. The transcription factor Twist1 limits pro-inflammatory cytokine production in T cells, but the role of T cell-derived cytokine mediators regulated by Twist1 in kidney damage has not been fully elucidated. To explore the role of T cell Twist1 in kidney scar formation, we subjected mice with T lymphocyte-specific deletion (“TKO”) of Twist1 and controls to the UUO.

Methods

129/SvEv mice with a floxed allele for the gene encoding Twist1 or TNFα were bred with CD4-Cre mice to yield Twist1 TKO or TNFα TKO mice with robust but selective deletion of Twist1 mRNA [>90% vs. WTs in CD4+ T cells, and >85% vs. WTs in CD8+ T cells; p<0.0001] or TNFα mRNA in T cells (published), respectively. Twist1 TKO, TNFα TKO, and WT controls underwent UUO with assessment of kidney fibrosis and T cell phenotype at 14 days.

Results

2 weeks after UUO, Twist1 TKO mice developed less kidney fibrosis compared to WTs as quantitated by western blot for Col1 (0.75±0.06 vs 1.0±0.05 au; p=0.02 ) and αSMA (0.65±0.01 vs 1.0±0.08 au; p=0.001) and by RT-PCR for Col1 (0.69±0.08 vs 1.0±0.10 au; p=0.048), fibronectin (0.76±0.07 vs 1.0±0.06 au; p=0.03), TGFβ1 (0.73±0.08 vs 1.0±0.04 au; p=0.004) and PAI-1 (0.47±0.05 vs 1.0±0.09 au; p=0.001). Twist1 TKO mice also showed attenuated kidney injury as indicated by NGAL mRNA expression (0.53±0.06 vs 1.0±0.16 au; p=0.04). Twist1 can suppress proinflammatory mediators such as TNFα and IL17A in T cells. At 14d, flow cytometry revealed similar T cell and macrophage numbers in the obstructed WT and Twist1 TKO kidneys. We then used fluorescent cell sorting to isolate CD4+ and CD8+ T cells from obstructed WT and Twist1 TKO kidneys. Sorted CD4+ T cells from Twist1 TKO kidneys expressed similar mRNA levels for TNFα and IL17A. Sorted CD8+ T cells from obstructed Twist1 TKO kidneys expressed higher mRNA levels for TNFα (1.8±0.39 vs 1.0±0.19 au; p=0.03), but not IL17A than WT controls. To further explore the role of TNFα in T cells during fibrogenesis, we subjected TNFα TKO and WT mice to UUO. We found TNFα deletion in T cells exaggerated kidney fibrosis and injury as quantitated by real time PCR for fibronectin (1.4±0.09 vs 1.0±0.13 au; p=0.03) and NGAL (1.3±0.10 vs 1.0±0.05 au; p=0.01) mRNA expression, respectively.

Conclusion

Twist1 in T cells drives fibrosis in the injured kidney, possibly by limiting TNFα production.

Funding

  • NIDDK Support