Abstract
During rheumatoid arthritis (RA), Tumor Necrosis Factor (TNF) activates fibroblast-like synoviocytes (FLS) inducing in a temporal order a constellation of genes, which perpetuate synovial inflammation. Although the molecular mechanisms regulating TNF-induced transcription are well characterized, little is known about the impact of mRNA stability on gene expression and the impact of TNF on decay rates of mRNA transcripts in FLS. To address these issues we performed RNA sequencing and genome-wide analysis of the mRNA stabilome in RA FLS. We found that TNF induces a biphasic gene expression program: initially, the inducible transcriptome consists primarily of unstable transcripts but progressively switches and becomes dominated by very stable transcripts. This temporal switch is due to: a) TNF-induced prolonged stabilization of previously unstable transcripts that enables progressive transcript accumulation over days and b) sustained expression and late induction of very stable transcripts. TNF-induced mRNA stabilization in RA FLS occurs during the late phase of TNF response, is MAPK-dependent, and involves several genes with pathogenic potential such as IL6, CXCL1, CXCL3, CXCL8/IL8, CCL2, and PTGS2. These results provide the first insights into genome-wide regulation of mRNA stability in RA FLS and highlight the potential contribution of dynamic regulation of the mRNA stabilome by TNF to chronic synovitis.
Highlights
Chronic sterile synovial inflammation and pannus are the hallmarks of rheumatoid arthritis (RA) [1]
In fibroblast-like synoviocytes (FLS) that had been stimulated with Tumor Necrosis Factor (TNF) for 24 or 72 hours, IL-6 transcripts persisted after addition of actinomycin D (Act D) (Fig 1A, bars 8–13)
By using primers specific for the fourth intronic region of IL6 to capture primary transcripts of IL6, we have verified that Act D and flavopiridol rapidly induce an almost complete inhibition of transcription even when added during the late phase (72 hours) of TNF stimulation (Fig 1D and 1E)
Summary
Chronic sterile synovial inflammation and pannus are the hallmarks of rheumatoid arthritis (RA) [1]. During the long-standing course of RA synovitis, chronic exposure to TNF and other inflammatory factors transforms FLS into synovial factories secreting a constellation of arthritogenic mediators [4,5] These mediators induce synovial recruitment, retention, activation and prolonged survival of immune cells, and promote osteoclastogenesis, cartilage degradation as well as synovial neoangiogenesis [6]. Dynamic regulation of the mRNA stabilome by TNF exhibited a temporal switch from an early phase dominated by unstable inducible transcripts to a late phase characterized by accumulation of stabilized and stable transcripts with pathogenic potential To our knowledge, this is the first genome-wide study implicating mRNA stability in the sustained inflammatory response of primary RA FLS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
