Kidney Week

Abstract: PO2438

NGAL Is Necessary for Antigen-Presenting Cells Recruitment and Proteinuria in the Mouse Kidney with Ureteral Obstruction

Session Information

• CKD: Inflammation, Endothelial Dysfunction, and Signaling
  November 04, 2021 | Location: On-Demand, Virtual Only
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2103 CKD (Non-Dialysis): Mechanisms

Authors

• Araos, Patricio A., Universidad Autonoma de Chile - Campus El Llano Subercaseaux, San Miguel, Chile

Patricio A. Araos, PhD

• Figueroa, Stefanny M., Universidad Autonoma de Chile - Campus El Llano Subercaseaux, San Miguel, Chile

Stefanny M. Figueroa,

• Rubio, Orlando Maximiliano, Universidad Autonoma de Chile - Campus El Llano Subercaseaux, San Miguel, Chile

Orlando Maximiliano Rubio,

• Reyes Osorio, Javier Ignacio, Universidad Autonoma de Chile - Campus El Llano Subercaseaux, San Miguel, Chile

Javier Ignacio Reyes Osorio,

• Amador, Cristián A., Universidad Autonoma de Chile - Campus El Llano Subercaseaux, San Miguel, Chile

Cristián A. Amador,

Group or Team Name

• Laboratorio de Fisiopatología Renal, Instituto de Ciencias Biomédicas

Background

Elevated levels of proteinuria are present in patients with chronic kidney disease (CKD) even with preserved kidney function. In this line, immune cells play a major role in the development and progression of renal inflammation in CKD. In particular, antigen presenting cells (APCs), such as macrophages (MØ) and dendritic cells (DCs) may play a pivotal role. Previous studies have demonstrated that neutrophil gelatinase-associated lipocalin, NGAL, is overexpressed during renal lesion. However, it is unknown whether there is a relationship between proteinuria and the APCs recruitment, and if it is dependent on NGAL. Our objective was to determine whether NGAL promotes proteinuria and APCs recruitment during the unilateral ureteral obstruction (UUO).

Methods

Male C57BL/6 Wild type (WT) and NGAL-KO mice (8-12 w.o.) were undergoing to UUO and to Sham surgery (Control) during 14 days (n=8). Creatinine and proteinuria were measured from pelvis urine of obstructed kidney. DCs (MHC-II⁺/CD11c⁺/F4/80^-/CD11b⁺ for DCs type-2 phenotype) and MØ (MHC-II⁺/CD11c⁺/F4/80⁺/CD11b⁺/CD80⁺ for M1 phenotype) recruitment were measured by flow cytometry. Additionally, WT-MØ were stimulated with albumin (10mg/mL, 24 h) and M1 genes evaluated by real-time PCR.

Results

We observed that the increased protein/creatinine ratio in the obstructed kidney of UUO WT mice was reduced in NGAL-KO mice (24.4±9.0 vs. 12.2±5.6 p<0.01). In vitro stimulation with albumin on macrophages from WT mice increased the mRNA levels of pro-inflammatory M1 markers (IL-12b, IL-23a, TNFα and iNOS; p<0.001). We did not observe changes in the M2 profile. Finally, we observed an early increase in the recruitment of DCs and M1 macrophages in WT UUO (MØ_Sham=6.9±1.2 vs MØ_UUO=60.0±24.4 cell/mg renal tissue; DCs_Sham=54.7±20.0 vs DCs_UUO=242±99.9 cell/mg renal tissue; p<0.01), which was prevented in UUO NGAL-KO mice (MØ_WT=60.0±24.4 vs MØ_NGAL-KO=30.2±7.8 cell/mg renal tissue; DCs_WT=242±99.9 vs DCs_NGAL-KO=83.1±9.6 cell/mg renal tissue; p<0.05).

Conclusion

Our results show that NGAL is necessary for DCs and MØ recruitment, in addition for the proteinuria increment in the obstructed kidney, suggesting a new pro-inflammatory mechanism of NGAL in CKD.
Supported by Fondecyt #1201251 and #3201016

Funding

• Government Support – Non-U.S.