Abstract: TH-PO0443
Altered Neutrophil Extracellular Trap Dynamics in C3 Glomerulopathy
Session Information
- Glomerular Diseases: Autoimmune Diseases
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Khandelwal, Priyanka, Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
- Khan, Meraj A., Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
- Licht, Christoph, Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
Background
C3 Glomerulopahty (C3G) is a complement-mediated kidney disease marked by proteinuria and progressive kidney failure. Our preliminary data shows glomerular infiltration of activated neutrophils with extensive neutrophil extracellular trap (NET) formation across treatment stages in C3G. We examined whether circulating C3G neutrophils are primed for NETosis and whether C3G serum alters NET formation and degradation
Methods
Neutrophils were isolated from treatment-naïve C3G patients (n=6) and healthy controls (n=6). NETosis was quantified by live-cell Sytox Green uptake over 12-hr in autologous serum, control serum (NHS) or heat-inactivated serum (HIS; complement negative control). We tested effect of calcium chelation (BAPTA-AM) and C3-inhibitor on NET generation; mitochondrial reactive oxygen species formation (ROS) was quantified. NET degradation was measured by PicoGreen assay after incubating preformed NETs with serum from C3G patients or controls, with or without DNase
Results
C3G neutrophils showed significantly higher NETosis than control neutrophils when incubated in autologous serum (mean difference 15.9%; adjusted P<0.001) with abundant MPO+/CitH3+ structures and minimal apoptosis. C3G neutrophils maintained elevated NETotic activity relative to control neutrophils when incubated in either C3G serum or NHS (mean differences 9.7% and 10.2%, respectively; P<0.001), consistent with an intrinsically primed phenotype. C3G serum induced excessive NETosis in healthy donor neutrophils compared to NHS or HIS, confirming the amplifying effect of complement-active serum. NET generation in C3G neutrophils was significantly attenuated with BAPTA-AM. C3G neutrophils had higher mitochondrial ROS production than controls. C3 inhibition significantly reduced NET formation, although citH3 stained neutrophils persisted. C3G serum significantly showed reduced NET degradation after 4-6 hrs compared to control serum. Spiking C3G serum with 1 U/L DNase significantly increased NET degradation, whereas DNase had no effect in controls
Conclusion
Neutrophils and NETs are important components of C3G pathogenesis. C3G neutrophils are intrinsically primed for NETosis. NET formation is driven by complement activation and is calcium/mitochondrial ROS dependent. NET degradation is impaired likely due to reduced DNase activity in C3G patients that might contribute to persistence of NETs within the glomeruli
Funding
- Government Support – Non-U.S.