Live imaging of monocyte subsets in immune complex-mediated glomerulonephritis reveals distinct phenotypes and effector functions
File(s)
Author(s)
Turner-Stokes, Tabitha
Type
Thesis
Abstract
Crescentic glomerulonephritis (GN) caused by deposition of immune complexes within the
glomerular capillary wall is a common cause of rapidly progressive glomerulonephritis and an
important cause of end-stage renal failure. Current treatment with generalised immunosuppression is suboptimal in terms of efficacy, and is associated with significant side
effects and long-term toxicity. Monocytes and macrophages are important in mediating
crescentic GN, but little work has been done to phenotype the subpopulations involved and
determine their respective contributions to glomerular inflammation.
I developed a live glomerular imaging model using confocal microscopy in order to monitor
intravascular monocyte subset behaviour during nephrotoxic nephritis (NTN) in a novel WKYhCD68-
GFP monocyte/macrophage reporter rat strain. Additionally, I used flow cytometry
and gene expression analysis to analyse ex vivo the glomerular leukocyte infiltrate during
NTN.
Using live glomerular imaging, I showed that non-classical monocytes surveyed the
glomerular endothelium via the b2 integrin LFA-1 in the steady state. During NTN, nonclassical
monocytes were recruited first, but subsequent recruitment and retention of
classical monocytes was associated with glomerular damage and the onset of proteinuria.
Importantly, monocytes recruited to the glomerular vasculature during NTN did not undergo
transendothelial migration. This finding suggests that inflammation in crescentic GN caused
by immune complex formation within the glomerulus is predominantly intravascular, driven
by dynamic interactions between intravascular blood monocytes and the endothelium.
Glomerular endothelial cells and non-classical monocytes overexpressed a distinct chemokine
axis, which may orchestrate inflammatory myeloid cell recruitment and expression of damage
mediators. Lewis rats, that are inherently resistant to experimental GN, demonstrated
reduced recruitment of classical monocytes during NTN, suggesting a role for CD16 in
mediating glomerular damage.
In conclusion, my data suggest that monocyte subsets with distinct phenotypes and effector
functions may be important in driving inflammation in experimental crescentic GN caused by
immune complex deposition within the glomerulus. LFA-1 dependent endothelial
surveillance by non-classical monocytes may detect immune complexes through CD16,
orchestrating the inflammatory response through intravascular retention of classical
monocytes, which results in glomerular damage and proteinuria.
glomerular capillary wall is a common cause of rapidly progressive glomerulonephritis and an
important cause of end-stage renal failure. Current treatment with generalised immunosuppression is suboptimal in terms of efficacy, and is associated with significant side
effects and long-term toxicity. Monocytes and macrophages are important in mediating
crescentic GN, but little work has been done to phenotype the subpopulations involved and
determine their respective contributions to glomerular inflammation.
I developed a live glomerular imaging model using confocal microscopy in order to monitor
intravascular monocyte subset behaviour during nephrotoxic nephritis (NTN) in a novel WKYhCD68-
GFP monocyte/macrophage reporter rat strain. Additionally, I used flow cytometry
and gene expression analysis to analyse ex vivo the glomerular leukocyte infiltrate during
NTN.
Using live glomerular imaging, I showed that non-classical monocytes surveyed the
glomerular endothelium via the b2 integrin LFA-1 in the steady state. During NTN, nonclassical
monocytes were recruited first, but subsequent recruitment and retention of
classical monocytes was associated with glomerular damage and the onset of proteinuria.
Importantly, monocytes recruited to the glomerular vasculature during NTN did not undergo
transendothelial migration. This finding suggests that inflammation in crescentic GN caused
by immune complex formation within the glomerulus is predominantly intravascular, driven
by dynamic interactions between intravascular blood monocytes and the endothelium.
Glomerular endothelial cells and non-classical monocytes overexpressed a distinct chemokine
axis, which may orchestrate inflammatory myeloid cell recruitment and expression of damage
mediators. Lewis rats, that are inherently resistant to experimental GN, demonstrated
reduced recruitment of classical monocytes during NTN, suggesting a role for CD16 in
mediating glomerular damage.
In conclusion, my data suggest that monocyte subsets with distinct phenotypes and effector
functions may be important in driving inflammation in experimental crescentic GN caused by
immune complex deposition within the glomerulus. LFA-1 dependent endothelial
surveillance by non-classical monocytes may detect immune complexes through CD16,
orchestrating the inflammatory response through intravascular retention of classical
monocytes, which results in glomerular damage and proteinuria.
Version
Open Access
Date Issued
2020-12
Date Awarded
2021-03
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Woollard, Kevin
Cook, Herbert
Pusey, Charles
Sponsor
Medical Research Council (Great Britain)
Grant Number
MR/M003159/1
Publisher Department
Department of Immunology and Inflammation
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)