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Kidney Week

Abstract: SA-PO608

Hes1, a Newly Identified Downstream Mediator of α7nAChR on Macrophages in the Cholinergic Anti-Inflammatory Pathway, Plays a Protective Role in AKI

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Inoue, Tsuyoshi, University of Virginia, Charlottesville, United States
  • Abe, Chikara, Gifu University, Gifu, Japan
  • Tanaka, Shinji, University of Virginia, Charlottesville, Virginia, United States
  • Rosin, Diane L., University of Virginia, Charlottesville, Virginia, United States
  • Nangaku, Masaomi, The University of Tokyo, Tokyo, Japan
  • Wada, Youichiro, The University of Tokyo, Tokyo, Japan
  • Okusa, Mark D., University of Virginia, Charlottesville, Virginia, United States
Background

The cholinergic anti-inflammatory pathway (CAP) links the nervous and immune systems and modulates innate and adaptive immunity. Activation of the CAP by vagus nerve stimulation (VNS) exerts protective effects in a wide variety of clinical disorders including rheumatoid arthritis and Crohn’s disease. The CAP involves splenic alpha7-nicotinic acetylcholine receptor (α7nAChR)-positive macrophages although their detailed role in vivo has yet to be established.

Methods

RNA-seq using peritoneal macrphages from WT and α7nAChRKO mice was performed after nicotine and/or LPS treatment. Kidney IRI (bilateral, 26 mins) was used as an acute kidney injury model and was performed 24 hr after VNS (left side, 5 Hz, 50 μA for 10 min) treatment or adoptive transfer of treated-macrophages. Kidney injury was evaluated 24 hr later using plasma creatinine, kidney Kim-1 mRNA expression and histology (H&E). TNF level in the media was measured by ELISA and RAW 264.7 cells were used as macrophages for the experiments requiring modifications of gene expression.

Results

Adoptive transfer of 1x105 nicotine-treated peritoneal macrophages from α7nAChR+/+ (α7WT; progeny control) but not from α7nAChR-/- (α7KO) mice protected kidneys of recipient mice from IRI, showing the importance of α7nAChR on macrophages. Nicotine-induced genes whose expressions were lower (<1/2 compared to α7nAChR+/+-derived cells) in α7nAChR-/--derived peritoneal macrophages were extracted by RNA-seq. We focused on hairy and enhancer of split-1 (Hes1), a basic helix-loop-helix (bHLH) transcription factor that acts as a transcriptional repressor of genes that require a bHLH protein for their transcription. VNS induced Hes1 expression in peritoneal macrophags. siRNA against Hes1 inhibited nicotine-induced TNF suppression, and Hes1 overexpression suppressed LPS-stimulated TNF induction in RAW 264.7 cells. Hes1 overexpression in RAW 264.7 cells mainly induced macrophage M2 markers (anti-inflammatory). Lastly we found that adoptive transfer of Hes1-overexpressing RAW 264.7 cells protected the kidney from IRI.

Conclusion

These data demonstrate that Hes1 is a new downstream signaling molecule of α7nAChR in the CAP.

Funding

  • NIDDK Support