Key Components of the Complement Lectin Pathway Are Not Only Required for the Development of Inflammatory Arthritis but Also Regulate the Transcription of Factor D

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

DOI

  • V Michael Holers, University of Colorado Anschutz Medical Campus
  • ,
  • Anna Borodovsky, Alnylam Pharmaceutical Inc., Boston, MA, United States.
  • ,
  • Robert I Scheinman, University of Colorado Anschutz Medical Campus
  • ,
  • Nhu Ho, University of Colorado Anschutz Medical Campus
  • ,
  • Joseline Ramos Ramirez, University of Colorado Anschutz Medical Campus
  • ,
  • József Dobó, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences
  • ,
  • Péter Gál, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences
  • ,
  • Jared Lindenberger, Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, United States.
  • ,
  • Annette G Hansen
  • Dhruv Desai, Alnylam Pharmaceutical Inc., Boston, MA, United States.
  • ,
  • Rasmus Pihl
  • Steffen Thiel
  • Nirmal K Banda, University of Colorado Anschutz Medical Campus

The complement system plays an important role in the pathogenesis of rheumatoid arthritis (RA). Besides driving lectin pathway (LP) activation, the mannan-binding lectin (MBL)-associated serine proteases (MASPs) also play a key role in regulating the alternative pathway (AP). We evaluated the effects of N-acetylgalactosamine (GalNAc)-conjugated MASP-1 and MASP-2 duplexes in vitro and in mice with and without arthritis to examine whether knockdown of MASP-1 and MASP-2 expression affects the development of arthritis. GalNAc-siRNAs for MASP-1 and MASP-2 demonstrated robust silencing of MASP-1 or MASP-2 at pM concentrations in vitro. To evaluate the impact of silencing in arthritic mice, we used the collagen antibody-induced arthritis (CAIA) mouse model of RA. Mice were injected a 10 mg/kg dose of GalNAc-siRNAs 3x s.q. prior to the induction of CAIA. Liver gene expression was examined using qRT-PCR, and protein levels were confirmed in the circulation by sandwich immunoassays and Western blot. At day 10, CAIA mice separately treated with MASP-1 and MASP-2 duplexes had a specific reduction in expression of liver MASP-1 (70-95%, p < 0.05) and MASP-2 (90%, p < 0.05) mRNA, respectively. MASP-1-siRNA treatment resulted in a 95% reduction in levels of MASP-1 protein in circulation with no effect on MASP-2 levels and clinical disease activity (CDA). In mice injected with MASP-2 duplex, there was a significant (p < 0.05) 90% decrease in ex vivo C4b deposition on mannan, with nearly complete elimination of MASP-2 in the circulation. MASP-2 silencing initially significantly decreased CDA by 60% but subsequently changed to a 40% decrease vs. control. Unexpectedly, GalNAc-siRNA-mediated knockdown of MASP-1 and MASP-2 revealed a marked effect of these proteins on the transcription of FD under normal physiological conditions, whereas LPS-induced inflammatory conditions reversed this effect on FD levels. LPS is recognized by Toll-like receptor 4 (TLR4), we found MBL not only binds to TLR4 an interaction with a Kd of 907 nM but also upregulated FD expression in differentiated adipocytes. We show that MASP-2 knockdown impairs the development of RA and that the interrelationship between proteins of the LP and the AP may extend to the transcriptional modulation of the FD gene.

Original languageEnglish
Article number201
JournalFrontiers in Immunology
Volume11
Number of pages18
ISSN1664-3224
DOIs
Publication statusPublished - 2020

    Research areas

  • Factor D, MBL-associated serine proteases, arthritis, complement, gene silencing, liver

See relations at Aarhus University Citationformats

ID: 181604417