Btk-specific inhibition blocks pathogenic plasma cell signatures and myeloid cell–associated damage in IFNα-driven lupus nephritis
Arna Katewa, Yugang Wang, Jason A. Hackney, Tao Huang, Eric Suto, Nandhini Ramamoorthi, Cary D. Austin, Meire Bremer, Jacob Zhi Chen, James J. Crawford, Kevin S. Currie, Peter Blomgren, Jason DeVoss, Julie A. DiPaolo, Jonathan Hau, Adam Johnson, Justin Lesch, Laura E. DeForge, Zhonghua Lin, Marya Liimatta, Joseph W. Lubach, Sami McVay, Zora Modrusan, Allen Nguyen, Chungkee Poon, Jianyong Wang, Lichuan Liu, Wyne P. Lee, Harvey Wong, Wendy B. Young, Michael J. Townsend, Karin Reif
Arna Katewa, Yugang Wang, Jason A. Hackney, Tao Huang, Eric Suto, Nandhini Ramamoorthi, Cary D. Austin, Meire Bremer, Jacob Zhi Chen, James J. Crawford, Kevin S. Currie, Peter Blomgren, Jason DeVoss, Julie A. DiPaolo, Jonathan Hau, Adam Johnson, Justin Lesch, Laura E. DeForge, Zhonghua Lin, Marya Liimatta, Joseph W. Lubach, Sami McVay, Zora Modrusan, Allen Nguyen, Chungkee Poon, Jianyong Wang, Lichuan Liu, Wyne P. Lee, Harvey Wong, Wendy B. Young, Michael J. Townsend, Karin Reif
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Research Article Immunology

Btk-specific inhibition blocks pathogenic plasma cell signatures and myeloid cell–associated damage in IFNα-driven lupus nephritis

Abstract

Systemic lupus erythematosus (SLE) is often associated with exaggerated B cell activation promoting plasma cell generation, immune-complex deposition in the kidney, renal infiltration of myeloid cells, and glomerular nephritis. Type-I IFNs amplify these autoimmune processes and promote severe disease. Bruton’s tyrosine kinase (Btk) inhibitors are considered novel therapies for SLE. We describe the characterization of a highly selective reversible Btk inhibitor, G-744. G-744 is efficacious, and superior to blocking BAFF and Syk, in ameliorating severe lupus nephritis in both spontaneous and IFNα-accelerated lupus in NZB/W_F1 mice in therapeutic regimens. Selective Btk inhibition ablated plasmablast generation, reduced autoantibodies, and — similar to cyclophosphamide — improved renal pathology in IFNα-accelerated lupus. Employing global transcriptional profiling of spleen and kidney coupled with cross-species human modular repertoire analyses, we identify similarities in the inflammatory process between mice and humans, and we demonstrate that G-744 reduced gene expression signatures essential for splenic B cell terminal differentiation, particularly the secretory pathway, as well as renal transcriptional profiles coupled with myeloid cell–mediated pathology and glomerular plus tubulointerstitial disease in human glomerulonephritis patients. These findings reveal the mechanism through which a selective Btk inhibitor blocks murine autoimmune kidney disease, highlighting pathway activity that may translate to human SLE.

Authors

Arna Katewa, Yugang Wang, Jason A. Hackney, Tao Huang, Eric Suto, Nandhini Ramamoorthi, Cary D. Austin, Meire Bremer, Jacob Zhi Chen, James J. Crawford, Kevin S. Currie, Peter Blomgren, Jason DeVoss, Julie A. DiPaolo, Jonathan Hau, Adam Johnson, Justin Lesch, Laura E. DeForge, Zhonghua Lin, Marya Liimatta, Joseph W. Lubach, Sami McVay, Zora Modrusan, Allen Nguyen, Chungkee Poon, Jianyong Wang, Lichuan Liu, Wyne P. Lee, Harvey Wong, Wendy B. Young, Michael J. Townsend, Karin Reif

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Figure 2

Specific Btk inhibition is superior to Syk or BAFF blockade in improving disease in IFNα-enhanced NZB/W_F1 LN.

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Specific Btk inhibition is superior to Syk or BAFF blockade in improving...
Fifteen-week-old NZB/W_F1 female mice (n = 10/group) were administered 1 injection of adenovirus containing murine IFNα (AdIFNα). Drug treatment started 3 weeks after AdIFNα injection with 100 mg/kg G-744 (triangles, dark-blue line), 60 mg/kg P505-15 (squares, red line), vehicle Hydroxypropylmethyl cellulose (HPMC) (open triangles, black line), 7.5 mg/kg BR3-Fc (circles, green line), Ig control antibodies (open circles, grey line), or Cyclophosphamide (CTX, stars, magenta line) as described in Methods. Graphs show (A) percentage of overall survival, (B) percentage progression-free survival, and (C) proteinuria score as measure of clinical efficacy. (D–H) Effect of drug treatment after 62 days at end of study in surviving mice (83 days after AdIFNα induction) on (D) renal glomerulopathy; (E) renal arteritis/periarteritis; (F) splenic peanut agglutinin (PNA+) germinal centers (GCs) (GCs were enumerated in formalin-fixed paraffin embedded [FFPE] spleen sections using IHC); (G) splenic marginal zone B cells (triple immunofluoresence staining of spleen with anti-CD4 (Alexa Fluor 5646, red), anti-Metallophilic Macrophages 1 (MOMA1) (FITC, green), anti-IgM (Aminomethylcoumarin [AMCA], blue) was performed on frozen spleen sections; arrows/+ signs refer to areas of IgM+ marginal zone B cells adjacent to and extending outwardly beyond the MOMA+ macrophage boundary) (20× magnification); and (H) splenic B220+ B cells (B cells were enumerated in FFPE spleen sections using IHC). (I) Serum anti-nuclear antibodies (ANA) Abs were assessed after 7-week treatment for the groups indicated. Statistics indicate (A–C) *P < 0.01, **P < 0.0001, G-744 versus vehicle; #P < 0.05, Cyclophosphamide versus vehicle; P < 0.05, P505-15 versus vehicle; &P < 0.05, BR3-Fc versus Ig control; §,$,¢P < 0.01, G-744 versus BR3-Fc, P505-15, or Cyclophosphamide, respectively. Groups were compared using (A and B) Log-rank Mantel-Cox test or (C) Kruskal Wallis test with Dunn’s correction; (D–F, H, I) Group means ± SEMs were calculated for each group; #P < 0.05, *P < 0.01, **P < 0.005, quantitative group means were compared with vehicle using (D–F, I) one-way ANOVA with Dunnett’s correction or (H) 2-tailed heteroscedastic t tests; symbols represent individual mice.