Therapeutic Blockade of Immune Complex-Mediated Glomerulonephritis by Highly Selective Inhibition of Bruton’s Tyrosine Kinase

Abstract

Lupus nephritis (LN) is a potentially dangerous end organ pathology that affects upwards of 60% of lupus patients. Bruton’s tyrosine kinase (BTK) is important for B cell development, Fc receptor signaling, and macrophage polarization. In this study, we investigated the effects of a novel, highly selective and potent BTK inhibitor, BI-BTK-1, in an inducible model of LN in which mice receive nephrotoxic serum (NTS) containing anti-glomerular antibodies. Mice were treated once daily with vehicle alone or BI-BTK-1, either prophylactically or therapeutically. When compared with control treated mice, NTS-challenged mice treated prophylactically with BI-BTK-1 exhibited significantly attenuated kidney disease, which was dose dependent. BI-BTK-1 treatment resulted in decreased infiltrating IBA-1+ cells, as well as C3 deposition within the kidney. RT-PCR on whole kidney RNA and serum profiling indicated that BTK inhibition significantly decreased levels of LN-relevant inflammatory cytokines and chemokines. Renal RNA expression profiling by RNA-seq revealed that BI-BTK-1 dramatically modulated pathways related to inflammation and glomerular injury. Importantly, when administered therapeutically, BI-BTK-1 reversed established proteinuria and improved renal histopathology. Our results highlight the important role for BTK in the pathogenesis of immune complex-mediated nephritis, and BTK inhibition as a promising therapeutic target for LN.

BTK inhibition ameliorates kidney disease in spontaneous lupus nephritis

“…We have now demonstrated its ability to prevent disease in three separate models of LN (NTN, MRL/lpr, and NZB/W), and moreover its ability to significantly improve survival. Importantly, we have also shown that BI-BTK-1 can reverse established and severe kidney disease both within the short term NTN model of inducible antibody mediated glomerulonephritis [12], and in this study in the MRL/lpr strain. This therapeutic endpoint is critical for transition of BTK inhibition into clinical use, where treatment is generally initiated after the onset of disease.…”

“…Beginning at 22 weeks of age, mice were dosed with BI-BTK-1 (~0.3 mg/kg, 1 mg/kg, 3 mg/kg, or 10 mg/kg) in chow formulation or control non-medicated chow (Research Diets, New Brunswick, NJ). BI-BTK-1 was described in detail in a previous publication [12]. A separate group of mice treated with cyclophosphamide (50 mg/kg intraperitoneally once weekly) was also assessed and compared to a PBS injected control group.…”

“…NZB/W tissues were processed at the Molecular Pathology Shared Resource of the Columbia University Herbert Irving Comprehensive Cancer Center, and MRL/lpr tissues were processed at the Albert Einstein College of Medicine Histology and Comparative Pathology Core. Renal pathology of both strains was scored by a blinded, experienced nephropathologist according to a previously published method [12]. In short, wire loop deposits, glomerular deposits, endocapillary proliferation, glomerular crescent formation (glomerular indices), interstitial inflammation, and tubular casts and dilatation (tubulointerstitial indices) were each given a score of 0–4, with 0 being no disease and 4 being severe disease.…”

“…We have previously described the use of a novel BTK inhibitor, BI-BTK-1, in an inducible kidney disease model known as nephrotoxic serum nephritis (NTN) [12]. However, these results were generated in a short term inducible model in non-autoimmune mice.…”

When the balance is broken: X-linked gene dosage from two X chromosomes and female-biased autoimmunity

“…Improved glomerular pathology and function were also observed after Btk inhibition . In an inducible model of lupus nephritis, Btk inhibition decreased complement deposition in the kidneys and reduced inflammatory cytokine production . Similar to the other X‐linked genes described above, transgenic mice overexpressing Btk in the B cell lineage developed lupus‐like disease which resembled human SLE (Table ).…”