Kidney Week

Abstract: FR-PO166

Characterization of Regulatory B Cells and IL-10 in Response to Ischemic Reperfusion

Session Information

• AKI: Mechanisms - II
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Yokota, Yunosuke, Kurume Daigaku Igakubu Daigakuin Igaku Kenkyuka, Kurume, Fukuoka, Japan

Yunosuke Yokota,

• Taguchi, Kensei, Kurume Daigaku Igakubu Daigakuin Igaku Kenkyuka, Kurume, Fukuoka, Japan

Kensei Taguchi,

• Ito, Sakuya, Kurume Daigaku Igakubu Daigakuin Igaku Kenkyuka, Kurume, Fukuoka, Japan

Sakuya Ito,

• Kodama, Goh, Kurume Daigaku Igakubu Daigakuin Igaku Kenkyuka, Kurume, Fukuoka, Japan

Goh Kodama,

• Fukami, Kei, Kurume Daigaku Igakubu Daigakuin Igaku Kenkyuka, Kurume, Fukuoka, Japan

Kei Fukami,

Background

Acute kidney injury (AKI) occurs in up to 20% of hospitalized patients. Interleukin-10 (IL-10), an anti-inflammatory cytokine, modulates the progression of AKI via reducing pro-inflammatory cytokines including TNF-α and IL-6. Regulatory B cells (Breg) is considered a main source of IL-10. Breg is a subset with a CD1d^hiCD5⁺CD19^hi phenotype and comprises 1-3% of B cells in mouse spleen with smaller numbers in the blood, lymph nodes, intestine, and peritoneum under basal condition. However, the distribution of Breg in response to AKI remains unknown. Thus, we investigated Breg infiltration into ischemic reperfusion (IR) kidneys and examined the expression pattern of IL-10-producing cells.

Methods

Experiment 1; To study if Breg infiltrates into IR kidneys, IR was constructed by clamping left renal artery for 30 minutes in IL-10-IRES-GFP mice. The kidneys were isolated on day1, 7, 14, 28, 42, and 70 after the surgery. Breg expression was examined by immunofluorescence staining. IL-10 expression was evaluated by real-time PCR. Experiment 2; A splenectomy was performed 7 days before ischemia IR surgery to investigate if splenectomy inhibits Breg infiltration.

Results

IL-10 was increased immediately after IR surgery and sustained until day7 in parallel with an increase in tubular injury. We identified that splenectomy did not attenuate renal dysfunction and fibrosis without any change in serum IL-10. Also, the increase in renal IL-10 mRNA was not altered by splenectomy. Large scan images demonstrated that number of interstitial GFP⁺ cells in IR kidneys was increased from day7 when compared to sham kidneys and remained high until chronic phase. We also found that GFP signal in mesangial area of uninjured kidneys; however, the GFP expression disappeared after IR surgery. This finding indicates that mesangial cells in IR kidneys might produce IL-10 which is inhibited by IR injury.

Conclusion

We identified that IL-10 mRNA is upregulated in response to IR injury with an increase in number of interstitial GFP⁺ cells. Mesangial cells might be capable of producing IL-10 which is inhibited by IR injury. Renal infiltration of IL-10-producing cells may be independent of spleen.