4F decreases IRF5 expression and activation in hearts of tight skin mice.

The apoAI mimetic 4F was designed to inhibit atherosclerosis by improving HDL. We reported that treating tight skin (Tsk(-/+)) mice, a model of systemic sclerosis (SSc), with 4F decreases inflammation and restores angiogenic potential in Tsk(-/+) hearts. Interferon regulating factor 5 (IRF5) is impo...

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Main Authors: Hao Xu, John G Krolikowski, Deron W Jones, Zhi-Dong Ge, Paul S Pagel, Kirkwood A Pritchard, Dorothée Weihrauch
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3522636?pdf=render
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author Hao Xu
John G Krolikowski
Deron W Jones
Zhi-Dong Ge
Paul S Pagel
Kirkwood A Pritchard
Dorothée Weihrauch
author_facet Hao Xu
John G Krolikowski
Deron W Jones
Zhi-Dong Ge
Paul S Pagel
Kirkwood A Pritchard
Dorothée Weihrauch
author_sort Hao Xu
collection DOAJ
description The apoAI mimetic 4F was designed to inhibit atherosclerosis by improving HDL. We reported that treating tight skin (Tsk(-/+)) mice, a model of systemic sclerosis (SSc), with 4F decreases inflammation and restores angiogenic potential in Tsk(-/+) hearts. Interferon regulating factor 5 (IRF5) is important in autoimmunity and apoptosis in immune cells. However, no studies were performed investigating IRF5 in myocardium. We hypothesize that 4F differentially modulates IRF5 expression and activation in Tsk(-/+) hearts. Posterior wall thickness was significantly increased in Tsk(-/+) compared to C57Bl/6J (control) and Tsk(-/+) mice with 4F treatment assessed by echoradiography highlighting reduction of fibrosis in 4F treated Tsk(-/+) mice. IRF5 in heart lysates from control and Tsk/+ with and without 4F treatment (sc, 1 mg/kg/d, 6-8 weeks) was determined. Phosphoserine, ubiquitin, ubiquitin K(63) on IRF5 were determined on immunoprecipitates of IRF5. Immunofluorescence and TUNEL assays in heart sections were used to determine positive nuclei for IRF5 and apoptosis, respectively. Fluorescence-labeled streptavidin (SA) was used to determine endothelial cell uptake of biotinylated 4F. SA-agarose pulldown and immunoblotting for IRF5 were used to determine 4F binding IRF5 in endothelial cell cytosolic fractions and to confirm biolayer interferometry studies. IRF5 levels in Tsk(-/+) hearts were similar to control. 4F treatments decrease IRF5 in Tsk(-/+) hearts and decrease phosphoserine and ubiquitin K(63) but increase total ubiquitin on IRF5 in Tsk(-/+) compared with levels on IRF5 in control hearts. 4F binds IRF5 by mechanisms favoring association over dissociation strong enough to pull down IRF5 from a mixture of endothelial cell cytosolic proteins. IRF5 positive nuclei and apoptotic cells in Tsk(-/+) hearts were increased compared with controls. 4F treatments decreased both measurements in Tsk(-/+) hearts. IRF5 activation in Tsk(-/+) hearts is increased. 4F treatments decrease IRF5 expression and activation in Tsk(-/+) hearts by a mechanism related to 4F's ability to bind IRF5.
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spelling doaj.art-bf04719fe615464c9728028c3033cd842022-12-22T03:16:54ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-01712e5204610.1371/journal.pone.00520464F decreases IRF5 expression and activation in hearts of tight skin mice.Hao XuJohn G KrolikowskiDeron W JonesZhi-Dong GePaul S PagelKirkwood A PritchardDorothée WeihrauchThe apoAI mimetic 4F was designed to inhibit atherosclerosis by improving HDL. We reported that treating tight skin (Tsk(-/+)) mice, a model of systemic sclerosis (SSc), with 4F decreases inflammation and restores angiogenic potential in Tsk(-/+) hearts. Interferon regulating factor 5 (IRF5) is important in autoimmunity and apoptosis in immune cells. However, no studies were performed investigating IRF5 in myocardium. We hypothesize that 4F differentially modulates IRF5 expression and activation in Tsk(-/+) hearts. Posterior wall thickness was significantly increased in Tsk(-/+) compared to C57Bl/6J (control) and Tsk(-/+) mice with 4F treatment assessed by echoradiography highlighting reduction of fibrosis in 4F treated Tsk(-/+) mice. IRF5 in heart lysates from control and Tsk/+ with and without 4F treatment (sc, 1 mg/kg/d, 6-8 weeks) was determined. Phosphoserine, ubiquitin, ubiquitin K(63) on IRF5 were determined on immunoprecipitates of IRF5. Immunofluorescence and TUNEL assays in heart sections were used to determine positive nuclei for IRF5 and apoptosis, respectively. Fluorescence-labeled streptavidin (SA) was used to determine endothelial cell uptake of biotinylated 4F. SA-agarose pulldown and immunoblotting for IRF5 were used to determine 4F binding IRF5 in endothelial cell cytosolic fractions and to confirm biolayer interferometry studies. IRF5 levels in Tsk(-/+) hearts were similar to control. 4F treatments decrease IRF5 in Tsk(-/+) hearts and decrease phosphoserine and ubiquitin K(63) but increase total ubiquitin on IRF5 in Tsk(-/+) compared with levels on IRF5 in control hearts. 4F binds IRF5 by mechanisms favoring association over dissociation strong enough to pull down IRF5 from a mixture of endothelial cell cytosolic proteins. IRF5 positive nuclei and apoptotic cells in Tsk(-/+) hearts were increased compared with controls. 4F treatments decreased both measurements in Tsk(-/+) hearts. IRF5 activation in Tsk(-/+) hearts is increased. 4F treatments decrease IRF5 expression and activation in Tsk(-/+) hearts by a mechanism related to 4F's ability to bind IRF5.http://europepmc.org/articles/PMC3522636?pdf=render
spellingShingle Hao Xu
John G Krolikowski
Deron W Jones
Zhi-Dong Ge
Paul S Pagel
Kirkwood A Pritchard
Dorothée Weihrauch
4F decreases IRF5 expression and activation in hearts of tight skin mice.
PLoS ONE
title 4F decreases IRF5 expression and activation in hearts of tight skin mice.
title_full 4F decreases IRF5 expression and activation in hearts of tight skin mice.
title_fullStr 4F decreases IRF5 expression and activation in hearts of tight skin mice.
title_full_unstemmed 4F decreases IRF5 expression and activation in hearts of tight skin mice.
title_short 4F decreases IRF5 expression and activation in hearts of tight skin mice.
title_sort 4f decreases irf5 expression and activation in hearts of tight skin mice
url http://europepmc.org/articles/PMC3522636?pdf=render
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