Kidney Week

Abstract: TH-OR058

Non-Classical Monocytes Act as Glomerular Sentinels, Sensing Deposited Immune Complexes and Orchestrating the Inflammatory Response via LFA-1 in Experimental Crescentic Glomerulonephritis

Session Information

• Glomerular Diseases: Spotlighting Immunology and Inflammation - I
  October 25, 2018 | Location: 8, San Diego Convention Center
  Abstract Time: 05:54 PM - 06:06 PM

Category: Glomerular Diseases

• 1202 Glomerular Diseases: Immunology and Inflammation

Authors

• Woollard, Kevin, Imperial College London, London, United Kingdom

Kevin Woollard



The Woollard lab is actively investigating the role of monocyte and macrophage subpopulations in regulating inflammatory and chronic kidney disease. We utilise imaging modalities to identify the in-vivo effector functions at the glomerular endothelial interface and to identify mechanisms of kidney recruitment and retention.

• Turner-Stokes, Tabitha, Imperial College London, London, United Kingdom

Tabitha Turner-Stokes,

• Garcia Diaz, Ana Isabel, Imperial College London, London, United Kingdom

Ana Isabel Garcia Diaz,

• Cook, H. Terence, Imperial College London, London, United Kingdom

H. Terence Cook,

• Pusey, Charles D., Imperial College London, London, United Kingdom

Charles D. Pusey,

Background

Non-classical monocytes (NC Mo) crawl along the resting endothelium, orchestrate the inflammatory response in some vascular beds and express high levels of FcγRIII(CD16). They may be important in triggering inflammation to immune complex (IC) deposition in glomerulonephritis (GN). Nephrotoxic Nephritis (NTN) in the WKY rat is a widely used, clinically-relevant model of crescentic GN but the distinct roles of myeloid subsets and the dynamics of their glomerular recruitment are unknown.

Methods

We developed a novel rat transgenic WKY-hCD68-GFP Mo/macrophage reporter. Mo subsets and endothelial cells were sorted from glomeruli of rats with NTN to investigate effector functions. Intravital confocal microscopy, with in vivo antibody labelling, was performed in the hydronephrotic kidney of anaesthetised WKY-hCD68-GFP rats, permitting high-resolution glomerular imaging and real-time, in vivo visualisation of myeloid recruitment and intravascular behaviour during NTN.

Results

Classical and NC Mo subsets were phenotyped as GFP^posCD43^loHIS48^hi and GFP^posCD43^hiHIS48^int respectively and neutrophils (PMNs) as GFP^negCD43^intHIS48^hi. RNA expression confirmed NC Mo were CD16^hiCX3CR1^hiCD14^loCCR2^lo relative to classical Mo i.e. homologous to mice and humans.

During intravital imaging, NC Mo surveyed the glomerular endothelium for prolonged periods in the steady state. Classical Mo and PMNs had only transient endothelial interactions. There were subset-specific differences in the behavioural response to IC deposition during NTN: Increased recruitment of NC Mo vs. increased retention of classical Mo and PMNs. CD16 and pro-inflammatory cytokines (IL-1β, TNFα) were upregulated in NC compared to classical Mo and a unique chemokine axis was overexpressed by the endothelium and NC Mo. LFA-1 blockade inhibited the distinctive migratory phenotype of NC Mo, reducing their recruitment and the retention of PMNs.

Conclusion

LFA-1-mediated endothelial surveillance by CD16^hi NC Mo may be an important mechanism for IC detection in GN, orchestrating the subsequent inflammatory response through a unique chemokine axis and cytokine-mediated retention of classical Mo and PMNs. Targeting NC Mo may lead to effective treatments for GN, with fewer side effects.

Funding

• Government Support - Non-U.S.