Research article

DNA-like class R inhibitory oligonucleotides (INH-ODNs) preferentially block autoantigen-induced B-cell and dendritic cell activation in vitro and autoantibody production in lupus-prone MRL-Fas^lpr/lpr mice in vivo

Petar Lenert¹ , Kei Yasuda² , Liliana Busconi² , Patrice Nelson² , Courtney Fleenor¹ , Radhika S Ratnabalasuriar¹ , Peter L Nagy¹ , Robert F Ashman¹ , Ian R Rifkin² and Ann Marshak-Rothstein²

¹  Departments of Internal Medicine and Pathology, Carver College of Medicine, The University of Iowa, Iowa City, C312GH, 200 Hawkins Drive, IA 52242, USA

²  Departments of Microbiology and Medicine, Boston University School of Medicine, Boston, 715 Albany Street, MA 02118, USA

author email corresponding author email

Arthritis Research & Therapy 2009, 11:R79doi:10.1186/ar2710

Published:	28 May 2009

See related editorial by Liu and Davidson, http://arthritis-research.com/content/11/3/116

Abstract

Introduction

B cells have many different roles in systemic lupus erythematosus (SLE), ranging from autoantigen recognition and processing to effector functions (for example, autoantibody and cytokine secretion). Recent studies have shown that intracellular nucleic acid-sensing receptors, Toll-like receptor (TLR) 7 and TLR9, play an important role in the pathogenesis of SLE. Dual engagement of rheumatoid factor-specific AM14 B cells through the B-cell receptor (BCR) and TLR7/9 results in marked proliferation of autoimmune B cells. Thus, strategies to preferentially block innate activation through TLRs in autoimmune B cells may be preferred over non-selective B-cell depletion.

Methods

We have developed a new generation of DNA-like compounds named class R inhibitory oligonucleotides (INH-ODNs). We tested their effectiveness in autoimmune B cells and interferon-alpha-producing dendritic cells in vitro and in lupus-prone MRL-Fas^lpr/lpr mice in vivo.

Results

Class R INH-ODNs have 10- to 30-fold higher inhibitory potency when autoreactive B cells are synergistically activated through the BCR and associated TLR7 or 9 than when stimulation occurs via non-BCR-engaged TLR7/9. Inhibition of TLR9 requires the presence of both CCT and GGG triplets in an INH-ODN, whereas the inhibition of the TLR7 pathway appears to be sequence-independent but dependent on the phosphorothioate backbone. This difference was also observed in the MRL-Fas^lpr/lpr mice in vivo, where the prototypic class R INH-ODN was more effective in curtailing abnormal autoantibody secretion and prolonging survival.

Conclusions

The increased potency of class R INH-ODNs for autoreactive B cells and dendritic cells may be beneficial for lupus patients by providing pathway-specific inhibition yet allowing them to generate protective immune response when needed.