Abstract: SA-PO617
Ablation of MRP8 in Myeloid Cells Ameliorates Glomerulonephritis by Affecting Macrophage Characterization
Session Information
- Glomerular Diseases: Immunology, Inflammation - II
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Hata, Yusuke, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Kuwabara, Takashige, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Mori, Kiyoshi, University of Shizuoka, School of Pharmaceut Sci, Shizuoka, Japan
- Umemoto, Shuro, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Kanki, Tomoko, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Fujimoto, Daisuke, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Nishiguchi, Yoshihiko, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Kakizoe, Yutaka, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Izumi, Yuichiro, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- Yokoi, Hideki, Kyoto University Graduate School of Medicine, Kyoto City, Japan
- Mukoyama, Masashi, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
Background
We previously reported that toll-like receptor 4 (TLR4) and its endogenous ligand, myeloid-related protein 8 (MRP8, S100A8), play important roles in the progression of diabetic nephropathy in mice. During these experiments, we unexpectedly observed that glomerular-infiltrated macrophages (MΦ) expressed MRP8 much more robustly than tubulointerstitial MΦ. However, the mechanisms and roles remain elusive.
Methods
We generated myeloid-lineage cell-specific MRP8 knockout mice (MyM8KO), and induced experimental nephrotoxic glomerulonephritis (NTN). Co-culture of MΦ with mesangial cells (Mes) or proximal tubular cells (PT) was performed to investigate the potential cellular crosstalk within glomeruli. Phalloidin staining was performed to evaluate the effects of MRP8 on bone marrow-derived MΦ (BMDM) generated from MyM8KO. BMDM was characterized as the M1/M2 ratio (M1/M2) determined by real-time PCR. Cell surface markers of peripheral leukocytes and glomerular-infiltrated MΦ were analyzed by flow cytometry (FCM). For effective sorting of MRP8-targeted cells, MyM8KO were crossed with floxed-STOP ZsGreen transgenic mice (MyM8KO-ZsG).
Results
In the NTN mice, ablation of MRP8 in myeloid-lineage cells significantly ameliorated glomerulonephritis as indicated by the reduction in proteinuria, glomerular exudative lesions, pro-inflammatory gene expressions and M1 dominancy in isolated glomeruli. In vitro, MRP8 expression was markedly induced in BMDM by co-culture with Mes but not with PT. This finding was recapitulated by stimulation with Mes-cultured supernatant (Mes-sup). Moreover, Mes-sup stimulation increased M1/M2 in wild-type BMDM, but such effect was blunted in BMDM obtained from MyM8KO. In BMDM stimulated with Mes-sup, deletion of MRP8 resulted in less stress fiber formation. FCM revealed that MyM8KO-ZsG NTN mice exhibited less ICAM-1 expression in both peripheral blood monocytes and glomerular-infiltrated MΦ.
Conclusion
These results indicate that myeloid-lineage cell-derived MRP8 could potentially contribute to glomerular injury upon NTN through intraglomerular cell-cell crosstalk, affecting MΦ characterization.