RELB MUTATIONS AND A MODEL OF NEPHRITIS
Dr Justin Chan Hsian Loon1,2
1RENAL MEDICINE, CANBERRA HEALTH SERVICES, CANBERRA, AUSTRALIA, 2JIANG LAB, DIVISION OF IMMUNOLOGY AND INFECTIOUS DISEASES, JOHN CURTIN SCHOOL OF MEDICAL RESEARCH, AUSTRALIAN NATIONAL UNIVERSITY, AUSTRALIA
Aim: To study the mechanism through which RelB variants result in nephritis and autoimmunity.
Background: Glomerulonephritis is a significant autoimmune disease impacting patient survival.RelB is involved in the non-canonical NF-kB pathway, regulating immune responses including lymphoid organ development, T and B cell proliferation.NF-Kb pathway has been associated with kidney disease such as IgA nephropathy and lupus nephritis. RelB -/- mice develop a phenotype marked by early multi-organ failure but normal kidney function.We identified a RelB variant that develops lethal kidney failure in mice at 4-6 weeks of age.
Methods: RelB knockout mice were generated using CRISPR/Cas9 with crRNA guides to alter exon 8. Absence of RelB protein was confirmed by Western Blot for the n and c-terminus of RelB. Organs were harvested for histopathological analysis.Spleen and thymus were harvested for immunophenotyping with flow cytometry. Serum was analysed for inflammatory cytokine changes.
Results: Mice developed end organ kidney failure by 6 weeks. Glomeruli were globally sclerosed and no active nephritis lesions identified. Liver and lung histology demonstrated organ inflammation known to occur with Relb-/- mice. There was a marked decrease in splenic mature B cell and thymic T cell populations. Myeloid lineages showed significant increases in neutrophils and Ly6c high monocytes. Splenic T cell populations showed increased Tregs and activated CD4+ cells. No significant changes in serum inflammatory cytokines were identified.
Conclusion: We identified a novel process where RelB variants alone can cause fulminant glomerulonephritis. This novel mouse model of nephritis serves as a possible avatar to study human glomerulonephritis and represents an important insight into populations with RELB variants and glomerulonephritis