Format

Send to

Choose Destination
Autoimmunity. 2011 Mar;44(2):82-9. doi: 10.3109/08916934.2010.491842. Epub 2010 Aug 9.

Exon 6 variants carried on systemic lupus erythematosus (SLE) risk haplotypes modulate IRF5 function.

Author information

1
Arthritis and Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.

Abstract

Interferon regulatory factor 5 (IRF5) regulates innate immune responses to viral infection. IRF5 genetic variants have been shown to be strongly associated with risk for systemic lupus erythematosus (SLE). Functional roles of IRF5 exon 6 structural variants that occur as part of a SLE risk-associated haplotype, including a 30-bp in/del (in/del-10) and a 48-bp splice-site variant (SV-16), have not been established. In this study, we used IRF5-deficient cells overexpressing human IRF5 (hIRF5) variants to investigate the roles of exon 6 in/del-10 and SV-16 in regulation of the apoptosis response, nuclear translocation, and ability to transactivate IRF5 responsive cytokines. We found that expression of IRF5 isoforms including either SV-16 or in/del-10 confers ability of IRF5 to impair the apoptotic response and correlates with reduced capacity for IRF5 nuclear translocation in MEFs after a DNA-damaging stimulus treatment. Interestingly, the presence or absence of both SV-16 and in/del-10 results in abrogation of both the anti-apoptotic and enhanced nuclear translocation effects of IRF5 expression. Only cells expressing IRF5 bearing SV-16 show increased IL-6 production upon lipopolysaccharide stimulation. MEFs expressing hIRF5 variants containing in/del-10 showed no significant difference from the control; however, cells carrying hIRF5 lacking both SV-16 and in/del-10 showed reduced IL-6 production. Our overall findings suggest that exon 6 SV-16 is more potent than in/del-10 for IRF5-driven resistance to apoptosis and promotion of cytokine production; however, in/del-10 co-expression can neutralize these effects of SV-16.

PMID:
20695768
PMCID:
PMC3104271
DOI:
10.3109/08916934.2010.491842
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Taylor & Francis Icon for PubMed Central
Loading ...
Support Center