[HTML][HTML] MicroRNAs miR-146a/b negatively modulate the senescence-associated inflammatory mediators IL-6 and IL-8

D Bhaumik, GK Scott, S Schokrpur, CK Patil, AV Orjalo… - Aging, 2009 - ncbi.nlm.nih.gov
D Bhaumik, GK Scott, S Schokrpur, CK Patil, AV Orjalo, F Rodier, GJ Lithgow, J Campisi
Aging, 2009ncbi.nlm.nih.gov
Senescence is a cellular program that irreversibly arrests the proliferation of damaged cells
and induces the secretion of the inflammatory mediators IL-6 and IL-8 which are part of a
larger senescence associated secretory phenotype (SASP). We screened quiescent and
senescent human fibroblasts for differentially expressed microRNAS (miRNAs) and found
that miRNAs 146a and 146b (miR-146a/b) were significantly elevated during senescence.
We suggest that delayed miR-146a/b induction might be a compensatory response to …
Abstract
Senescence is a cellular program that irreversibly arrests the proliferation of damaged cells and induces the secretion of the inflammatory mediators IL-6 and IL-8 which are part of a larger senescence associated secretory phenotype (SASP). We screened quiescent and senescent human fibroblasts for differentially expressed microRNAS (miRNAs) and found that miRNAs 146a and 146b (miR-146a/b) were significantly elevated during senescence. We suggest that delayed miR-146a/b induction might be a compensatory response to restrain inflammation. Indeed, ectopic expression of miR-146a/b in primary human fibroblasts suppressed IL-6 and IL-8 secretion and downregulated IRAK1, a crucial component of the IL-1 receptor signal transduction pathway. Cells undergoing senescence without induction of a robust SASP did not express miR-146a/b. Further, IL-1α neutralizing antibodies abolished both miR-146a/b expression and IL-6 secretion. Our findings expand the biological contexts in which miRNA-146a/b modulates inflammatory responses. They suggest that IL-1 receptor signaling initiates both miR-146a/b upregulation and cytokine secretion, and that miR-146a/b is expressed in response to rising inflammatory cytokine levels as part of a negative feedback loop that restrains excessive SASP activity.
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