Abstract 120: Pericytes Contribute To Myofibroblast Expansion And Vascular Maturation In The Infarcted Heart

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Linda Alex ◽  
Kai Su ◽  
Izabela Tuleta ◽  
Nikolaos G Frangogiannis
Keyword(s):  
Lineage Tracing ◽  
Cytokine Gene Expression ◽  
Infarct Zone ◽  
Mural Cell ◽  
Infarcted Myocardium ◽  
Reporter Mice ◽  
Infarct Healing ◽  
Subsequent Activation ◽  
Vascular Maturation

Infarct healing is dependent on recruitment of inflammatory leukocytes and subsequent activation of myofibroblasts (MF) and neovessel formation, ultimately resulting in formation of a highly vascularized collagen-enriched scar. Though the heart has an abundant population of periendothelial pericytes, its role in wound healing upon myocardial infarction (MI) has not been studied. We hypothesized that in the infarcted myocardium, pericytes may become activated, contributing to inflammatory, fibrotic and angiogenic responses. We used pericyte/fibroblast reporter mice (NG2 DsRed ;PDGFRα GFP ), lineage tracing studies and in vitro approaches to study the fate and role of pericytes in the infarcted myocardium. In normal hearts, NG2+/PDGFRα- pericytes and PDGFRα+/NG2- fibroblasts had distinct transcriptomic profiles. Pericytes expressed mural genes like Acta2 , Pdgfrb and low amounts of extracellular matrix (ECM) genes, whereas fibroblasts synthesized collagens, Timp2/3 and matricellular genes. 7 days post-MI, expansion of the NG2+ population in the infarct zone was associated with emergence of non-mural NG2+/αSMA+ cells with MF characteristics. FACS-sorted NG2+/PDGFRα- cells from 7-day infarcts expressed higher levels of collagens when compared to NG2+/PDGFRα- cells from normal hearts. Infarct pericytes had high integrin and MMP14 expression, reflecting an activated migratory phenotype. Lineage tracing using NG2CreER TM ;Rosa tdTomato ;PDGFRα GFP mice showed that 5.7%±1.04 of PDGFRα+ fibroblasts and 10.49%±2.73 of infarct MFs were derived from NG2+ lineage. Pericyte-derived fibroblasts exhibited higher ECM gene synthesis, in comparison to fibroblasts from non-pericyte origin, while pericyte-derived mural cells showed accentuated inflammatory cytokine gene expression. Immunostaining showed pericytes actively contribute to vascular maturation, forming a mural cell coat enwrapping infarct neovessels. In vitro, TGFβ induced integrins, collagens and MMPs in human pericytes, similar to the changes observed in infarct pericytes. Taken together, our evidences show that after MI, pericytes become activated and contribute to repair by undergoing conversion to a subset of myofibroblasts and by coating infarct neovessels.

Abstract MP123: The Fate and Role of Pericytes in Repair and Remodeling of the Infarcted Heart

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Linda Alex ◽  
Ya Su ◽  
Nikolaos G Frangogiannis
Keyword(s):  
Lineage Tracing ◽  
Mrna Levels ◽  
Infarct Zone ◽  
Subsequent Formation ◽  
Mural Cells ◽  
Infarcted Heart ◽  
Reporter Mice ◽  
Ng2 Cells ◽  
Migratory Phenotype

Repair of the infarcted heart is dependent on inflammation-driven activation of myofibroblasts (MFs) and subsequent formation of a scar. Though pericytes have been implicated in injury-associated fibroblast activation in several organs, their potential role in cardiac repair and fibrosis has not been studied. We hypothesized that myocardial infarction (MI) may induce pericyte activation, contributing to repair through pericyte to MF conversion, secretion of fibrogenic mediators, or regulation of angiogenesis. In order to test the hypothesis, we generated pericyte/fibroblast reporter mice (NG2 DsRed ;PDGFRα GFP ). In normal myocardium, NG2 labeled peri-endothelial mural cells that coexpressed PDGFRβ, whereas PDGFRα identified interstitial cells with fibroblast characteristics. Pericytes and fibroblasts had distinct transcriptomic profiles: NG2+/PDGFRα- pericytes expressed αSMA and low amounts of extracellular matrix (ECM) genes, whereas PDGFRα+/NG2- fibroblasts synthesized collagens. Pericyte rarefaction was noted in the necrotic core 3 days after non-reperfused MI. 3-7 days post MI, expansion of the NG2+ population in the infarct zone was associated with emergence of non-mural NG2+/αSMA+ cells with MF characteristics. FACS-sorted NG2+/PDGFRα- cells from 7-day infarcts expressed higher levels of ColIα2 (7.2±1.0-fold) and ColIIIα1 (8.9±1.14-fold), when compared to NG2+/PDGFRα- cells from normal hearts. NG2+ cells had high mRNA levels of integrins α1, αV, β1, and β5, and of MMP14, reflecting an activated migratory phenotype. To examine whether expression of ECM genes by infarct pericytes is due to fibroblast conversion, we did lineage tracing studies using NG2CreER TM ;Rosa tdTomato mice bred with the PDGFRα GFP line for reliable fibroblast identification. 7 days post MI, 5.7%±1.04 of PDGFRα+ fibroblasts were derived from NG2+ cells. Also, αSMA staining showed that 10.49%±2.73 of infarct MFs were derived from NG2+ lineage. The majority of mural cells wrapping neovessels were derived from NG2+ cells, suggesting a role for resident pericytes in infarct angiogenesis. In conclusion, upon MI, pericytes become activated and contribute to repair by undergoing conversion to a subset of myofibroblasts and by coating infarct neovessels.

scholarly journals An organotypic in vitro model of matured blood vessels

2020 ◽  
Author(s):  
Jaehyun Lee ◽  
Esak Lee
Keyword(s):  
Smooth Muscle ◽  
Blood Vessels ◽  
Three Dimensional ◽  
Vascular Diseases ◽  
Mural Cell ◽  
Vessel Maturation ◽  
Vascular Physiology ◽  
Vitro Model ◽  
Vascular Maturation

AbstractAngiogenesis is a physiological process in which brand-new blood vessels are formed from pre-existing blood vessels. The angiogenic processes are achieved by multiple steps, including angiogenic vascular sprouting, lumen formation, mural cell (e.g., smooth muscle cells) recruitment, and vessel stabilization by the mural cell coverage of the neovessels. Especially, mural cell recruitment to and coverage of the newly formed endothelium is a fundamental process to provide fully matured, functional blood vessels. Although investigation of the mural cell interactions with endothelial cells is crucial not only for better understanding of vascular physiology, but also for treating numerous vascular diseases, there has been a lack of three-dimensional (3D) in vitro models that recapitulate spontaneous processes of the vascular maturation. In this study, we describe an organotypic in vitro model that represents multi-step, spontaneous vascular maturation processes, which includes angiogenic vessel sprouting, smooth muscle cell (SMC) recruitment, and the SMC coverage of the neovessels. Using the system, we could spatiotemporally control vessel sprouting and vessel stabilization/maturation; and revealed an optimal condition that could reconstitute SMC-covered, matured blood vessels in 3D in vitro. We may provide a new platform for future mechanism studies of vascular interactions to mural cells and vessel maturation; and for pre-clinical screening and validation of therapeutic agent candidates for treating vascular diseases.

Abstract 13911: Interleukin-5-induced Eosinophil Population Improves Cardiac Function After Myocardial Infarction

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jun-Yan Xu ◽  
Wen-Yang Jiang ◽  
Yu-Yan Xiong ◽  
Rui-Jie Tang ◽  
Yu Ning ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Western Blot ◽  
Macrophage Polarization ◽  
M2 Macrophages ◽  
Infarct Zone ◽  
Infarcted Myocardium ◽  
Infarcted Heart

Background: Eosinophils have been commonly recognized as one of the major participants in helminth infection and allergic diseases. Recent studies suggest that these innate immune cells mediate tissue repairs after muscle, hepatic, or endometrial injuries. Yet, the precise role of eosinophils in myocardial infarction (MI) remains unclear. Interleukin (IL)-5 is the most important cytokines that are responsible for the development, activation, and survival of eosinophils. Here, we report a role of IL-5 in infarcted heart. Methods and Results: MI was induced by permanent ligation of left anterior descending coronary artery in wild-type C57BL/6 mice. Western blot show that infarcted heart IL-5 expression is increased by 2.35-fold (P<0.01) higher than their expression in the heart of sham mice at day 5 after surgery. External supply of recombinant mouse IL-5 (100 μg/kg/day for 3 days) reduces the infarct size (by 13.38%, P<0.01), increases ejection fraction (from 32.41% to 43.93%, P<0.01), and increases angiogenesis (CD31 area from 3.35% to 4.14%, P=0.03) in the peri-infarct zone. An expansion of eosinophils is observed in both the peripheral blood and infarcted myocardium after IL-5 administration. Pharmacological depletion of eosinophils by TRFK5 pretreatment mutes the beneficial effects of IL-5 in MI mice. Mechanistic studies also demonstrate that IL-5 increases the accumulation of M2 macrophages in infarcted myocardium at day 7 post-MI. In vitro co-culture experiments reveal that eosinophils shift bone marrow-derived macrophage polarization towards the M2 phenotypes. This effect is abolished by IL-4 neutralizing antibody, but not IL-10 or IL-13 neutralization. Western blot analyses show that eosinophils promote the macrophage downstream STAT6 phosphorylation. Conclusions: We demonstrate here that IL-5 facilitates the recovery of post-MI cardiac function by promoting eosinophils accumulation and subsequent polarization of M2 macrophages via the IL-4/STAT6 axis.

scholarly journals Identification of a multipotent Twist2-expressing cell population in the adult heart

2018 ◽  
Vol 115 (36) ◽  
pp. E8430-E8439 ◽  
Author(s):  
Yi-Li Min ◽  
Priscilla Jaichander ◽  
Efrain Sanchez-Ortiz ◽  
Svetlana Bezprozvannaya ◽  
Venkat S. Malladi ◽  
...  
Keyword(s):  
Cell Population ◽  
De Novo ◽  
Lineage Tracing ◽  
Cell Fates ◽  
Mesodermal Cell ◽  
Adult Heart ◽  
Reporter Mice ◽  
Unique Cell ◽  
Cellular Components

Twist transcription factors function as ancestral regulators of mesodermal cell fates in organisms ranging from Drosophila to mammals. Through lineage tracing of Twist2 (Tw2)-expressing cells with tamoxifen-inducible Tw2-CreERT2 and tdTomato (tdTO) reporter mice, we discovered a unique cell population that progressively contributes to cardiomyocytes (CMs), endothelial cells, and fibroblasts in the adult heart. Clonal analysis confirmed the ability of Tw2-derived tdTO+ (Tw2-tdTO+) cells to form CMs in vitro. Within the adult heart, Tw2-tdTO+ CMs accounted for ∼13% of total CMs, the majority of which resulted from fusion of Tw2-tdTO+ cells with existing CMs. Tw2-tdTO+ cells also contribute to cardiac remodeling after injury. We conclude that Tw2-tdTO+ cells participate in lifelong maintenance of cardiac function, at least in part through de novo formation of CMs and fusion with preexisting CMs, as well as in the genesis of other cellular components of the adult heart.

scholarly journals Activation of two distinct Sox9-EGFP-expressing intestinal stem cell populations during crypt regeneration after irradiation

2012 ◽  
Vol 302 (10) ◽  
pp. G1111-G1132 ◽  
Author(s):  
Laurianne Van Landeghem ◽  
M. Agostina Santoro ◽  
Adrienne E. Krebs ◽  
Amanda T. Mah ◽  
Jeffrey J. Dehmer ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Populations ◽  
Intestinal Epithelial ◽  
P53 Signaling ◽  
Reporter Mice ◽  
Radiation Induced ◽  
Molecular Phenotypes ◽  
Stem Cell Populations ◽  
Induced Changes

Recent identification of intestinal epithelial stem cell (ISC) markers and development of ISC reporter mice permit visualization and isolation of regenerating ISCs after radiation to define their functional and molecular phenotypes. Previous studies in uninjured intestine of Sox9-EGFP reporter mice demonstrate that ISCs express low levels of Sox9-EGFP (Sox9-EGFP Low), whereas enteroendocrine cells (EEC) express high levels of Sox9-EGFP (Sox9-EGFP High). We hypothesized that Sox9-EGFP Low ISCs would expand after radiation, exhibit enhanced proliferative capacities, and adopt a distinct gene expression profile associated with rapid proliferation. Sox9-EGFP mice were given 14 Gy abdominal radiation and studied between days 3 and 9 postradiation. Radiation-induced changes in number, growth, and transcriptome of the different Sox9-EGFP cell populations were determined by histology, flow cytometry, in vitro culture assays, and microarray. Microarray confirmed that nonirradiated Sox9-EGFP Low cells are enriched for Lgr5 mRNA and mRNAs enriched in Lgr5-ISCs and identified additional putative ISC markers. Sox9-EGFP High cells were enriched for EEC markers, as well as Bmi1 and Hopx, which are putative markers of quiescent ISCs. Irradiation caused complete crypt loss, followed by expansion and hyperproliferation of Sox9-EGFP Low cells. From nonirradiated intestine, only Sox9-EGFP Low cells exhibited ISC characteristics of forming organoids in culture, whereas during regeneration both Sox9-EGFP Low and High cells formed organoids. Microarray demonstrated that regenerating Sox9-EGFP High cells exhibited transcriptomic changes linked to p53-signaling and ISC-like functions including DNA repair and reduced oxidative metabolism. These findings support a model in which Sox9-EGFP Low cells represent active ISCs, Sox9-EGFP High cells contain radiation-activatable cells with ISC characteristics, and both participate in crypt regeneration.

Integrative analysis of the human brain mural cell transcriptome

2021 ◽  
pp. 0271678X2110137
Author(s):  
Benjamin D Gastfriend ◽  
Koji L Foreman ◽  
Moriah E Katt ◽  
Sean P Palecek ◽  
Eric V Shusta
Keyword(s):  
Human Brain ◽  
Cell Function ◽  
In Vitro Models ◽  
Molecular Characteristics ◽  
Mural Cell ◽  
Mural Cells ◽  
Brain Pericytes ◽  
Mouse Species ◽  
Cell Transcriptome

Brain mural cells, including pericytes and vascular smooth muscle cells, are important for vascular development, blood-brain barrier function, and neurovascular coupling, but the molecular characteristics of human brain mural cells are incompletely characterized. Single cell RNA-sequencing (scRNA-seq) is increasingly being applied to assess cellular diversity in the human brain, but the scarcity of mural cells in whole brain samples has limited their molecular profiling. Here, we leverage the combined power of multiple independent human brain scRNA-seq datasets to build a transcriptomic database of human brain mural cells. We use this combined dataset to determine human-mouse species differences in mural cell transcriptomes, culture-induced dedifferentiation of human brain pericytes, and human mural cell organotypicity, with several key findings validated by RNA fluorescence in situ hybridization. Together, this work improves knowledge regarding the molecular constituents of human brain mural cells, serves as a resource for hypothesis generation in understanding brain mural cell function, and will facilitate comparative evaluation of animal and in vitro models.

Abstract 427: Tissue Inhibitor of Matrix Metalloproteinase-3 (TIMP3) Provides Beneficial Effects Post-MI by Promoting Angiogenesis

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Abhijit R Takawale ◽  
Pu Zhang ◽  
Ratnadeep Basu ◽  
Abul Azad ◽  
Maikel Farhan ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Left Ventricular ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Lv Function ◽  
Vascular Density ◽  
Tissue Inhibitor ◽  
Infarct Zone ◽  
Fibrin Gel ◽  
Beneficial Effects

Introduction: Myocardial infarction (MI) results in loss of cardiomyocytes, adverse extracellular matrix (ECM) remodelling, leading to left ventricular (LV) dilation and dysfunction. Tissue inhibitor of metalloproteinase (TIMPs) are MMP inhibitors, main regulators of ECM integrity. TIMPs can also regulate other aspects of myocardial remodeling such as hypertrophy, fibrosis and inflammation. TIMP3 levels are reduced in the peri-infarct zone within 24 hours post-MI in mice. Hypothesis: Replenishment of TIMP3 post-MI limit infarct expansion, and attenuate LV dilation and dysfunction. Methods: MI was induced in adult male wildtype (C57BL/6) mice by ligation of the left anterior descending artery. Adenoviral constructs expressing human TIMP3 (Ad- hTIMP3) or no-TIMP (Ad-Null, control) were injected in the peri-infarct zone (5.4x10 7 pfu, 5 injections/heart). Cardiac function was assessed by echocardiography. Cardiomyocyte density (WGA/DAPI staining), vascular density (Fluo-lectin injection, CD31 IHC), ECM composition (PSR staining) were assessed at 3 and 7 days post-MI. In vitro, angiogenic potency of TIMP3 (rTIMP3) was assessed using the 3D fibrin gel-based angiogenesis assay using primary human vascular (HUVECs) and coronary artery endothelial cells (HCAECs), and co-IP between TIMP3 and VEGFR2. Results: Ad-TIMP3 injections significantly improved LV function and reduced LV dilation as compared to Ad-Null group post-MI. Infarct size was markedly reduced with TIMP3 injections and more viable myocytes were preserved in the infarct zone at 1wk post-MI. Ad-TIMP3-MI group showed a higher density of endothelial cells and increased coronary density in the infarct and peri-infarct regions compared to the Ad-null group. This suggested that Ad-TIMP3 promotes angiogenesis in the infarcted myocardium. In vitro studies confirmed that rTIMP3 promoted angiogenesis/sprouting in human endothelial cells up to100ng/ml. However at higher concentrations (>1ug/ml), rTIMP3 exerted anti-angiogenic effects by binding to VEGFR2. This function of rTIMP3 appears to be through an MMP-inhibitory mechanism. Conclusion: The novel pro-angiogenic function of TIMP3 post-MI could provide additional beneficial effects in post-MI treatment.

Abstract P011: Endothelial Differentiation and Lineage Tracing in Adipocyte-Derived Multipotent Cells

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Medet Jumabay ◽  
Raushan Abdmaulen ◽  
Yucheng Yao ◽  
Kristina Bostrom
Keyword(s):  
Stem Cell ◽  
Lineage Tracing ◽  
Collagen Gels ◽  
Cellular Origin ◽  
Differentiated Cells ◽  
Stem Cell Source ◽  
Cardiovascular Regeneration ◽  
Morphogenetic Protein ◽  
Dfat Cells

We previously showed that so-called de-differentiated fat (DFAT) cells, which are derived from mature white adipocytes, spontaneously differentiate into beating cardiomyocytes. Our aim in this study was to investigate if DFAT cells also differentiate into endothelial cells (ECs) in vitro, and to further examine the cellular origin of DFAT cells as well as adipose stromal cells (ASCs) using lineage tracing. First, we examined DFAT and ASCs prepared from aP2-Cre+/+;LacZ ROSA(R26R)+/+ double transgenic mice, which express LacZ under the aP2 promoter. The results revealed that 99.9% of DFAT cells and 45% of the ASCs stained positive for LacZ, supporting that the DFAT cells and part of the ASCs are of adipocytic origin. Second, we allowed newly isolated DFAT cells to spontaneously undergo EC differentiation, which was monitored by expression of EC lineage markers as determined by real-time PCR, immunofluorescence, and FACS. Expression of the EC markers CD31 and VE-cadherin increased progressively during 2 weeks in culture, the percentage of CD31(+) cells increased from 0.0% to 8.3%, and the cells formed multi-cellular tube structures when placed in Matrigel™/Collagen gels. The data supported that a fraction of the DFAT cells differentiate into ECs. Furthermore, the EC differentiation could be enhanced in DFAT cells by treatment with bone morphogenetic protein (BMP)-4 and BMP-9. In addition to EC differentiation, the DFAT cells also expressed markers of other cardiovascular lineages including smooth muscle cells and pericytes. The multipotency of DFAT cells suggests that cellular de-differentiation might be a way for differentiated cells to regain stem cell-like properties. Thus, white mature adipocytes maybe a new stem cell source for cardiovascular regeneration.

Abstract 255: A Fibroblast Population Shares A Developmental Origin With Cardiovascular Lineages

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Sara Ranjbarvaziri ◽  
Shah Ali ◽  
Mahmood Talkhabi ◽  
Peng Zhao ◽  
Young-Jae Nam ◽  
...  
Keyword(s):  
Heart Development ◽  
Cardiac Fibroblasts ◽  
Immunohistochemical Analysis ◽  
Cell Types ◽  
Mouse Heart ◽  
Developmental Potential ◽  
Reporter Mice ◽  
Significant Difference ◽  
Definition Of

Rationale: The traditional definition of “cardiovascular” lineages describes the eponymous cell types - cardiomyoctes, endothelial cells, and smooth muscle cells - that arise from a common mesodermal progenitor cell during heart development. Fibroblasts are an abundant mesenchymal population in the mammalian heart which may have multiple, discrete developmental origins. Mesp1 represents the earliest marker of cardiovascular progenitors, contributing to the majority of cardiac lineages. To date no link between Mesp1 and fibroblast generation has been reported. Objective: We hypothesized progenitor cells expressing Mesp1 can also give rise to cardiac fibroblasts during heart development. Methods and Results: We generated Mesp1cre/+;R26RmTmG reporter mice where Cre-mediated recombination results in GFP activation in all Mesp1 expressing cells and their progeny. To explore their developmental potential, we isolated GFP+ cells from E7.5 Mesp1cre/+;R26RmTmG mouse. In vitro culture and transplantation studies into SCID mouse kidney capsule as wells as chick embryos showed fibroblastic adoption. Results showed that at E9.5 Mesp1+ and Mesp1- progenitors contributed to the proepicardium organ and later at E11.5 they formed epicardium. Analysis of adult hearts demonstrated that the majority of cardiac fibroblasts are derived from Mesp1 expressing cells. Immunohistochemical analysis of heart sections demonstrated expression of fibroblast markers (including DDR2, PDGFRα and Col1) in cells derived from both Mesp1+ and Mesp1- progenitors. Additionally, we investigated whether the two distinct fibroblast populations have different potency towards reprogramming to cardiomyocytes. Results showed no significant difference between Mesp1 and non-Mesp1 isolated fibroblasts to convert to cardiomyocyte fate. Conclusions: Our data demonstrates that cardiovascular progenitors expressing Mesp1 contribute to the proepicardium. These cells, as cardiovascular progenitors, also give rise to the highest portion of cardiac fibroblasts in the mouse heart.

scholarly journals Febrile-range temperature modifies cytokine gene expression in LPS-stimulated macrophages by differentially modifying NF-κB recruitment to cytokine gene promoters

2010 ◽  
Vol 298 (1) ◽  
pp. C171-C181 ◽  
Author(s):  
Zachary A. Cooper ◽  
Arundhati Ghosh ◽  
Aditi Gupta ◽  
Tapan Maity ◽  
Ivor J. Benjamin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Receptor Activation ◽  
Cytokine Gene Expression ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Heat Shock Factor 1 ◽  
Gene Promoters ◽  
Cytokine Gene ◽  
Tnf Α

We previously showed that exposure to febrile-range temperatures (FRT, 39.5–40°C) reduces LPS-induced TNF-α expression, in part through the direct interaction of heat shock factor-1 (HSF1) with the TNF-α gene promoter. However, it is not known whether exposure to FRT also modifies more proximal LPS-induced signaling events. Using HSF1-null mice, we confirmed that HSF1 is required for FRT-induced repression of TNF-α in vitro by LPS-stimulated bone marrow-derived macrophages and in vivo in mice challenged intratracheally with LPS. Exposing LPS-stimulated RAW 264.7 mouse macrophages to FRT reduced TNF-α expression while increasing IL-1β expression despite the two genes sharing a common myeloid differentiation protein-88 (MyD88)-dependent pathway. Global activation of the three LPS-induced signaling intermediates that lead to cytokine gene expression, ERK and p38 MAPKs and NF-κB, was not affected by exposing RAW 264.7 cells to FRT as assessed by ERK and p38 phosphorylation and NF-κB in vitro DNA-binding activity and activation of a NF-κB-dependent synthetic promoter. However, chromatin immunoprecipitation (ChIP) analysis demonstrated that exposure to FRT reduced LPS-induced recruitment of NF-κB p65 to the TNF-α promoter while simultaneously increasing its recruitment to the IL-1β promoter. These data suggest that FRT exerts its effects on cytokine gene expression in a gene-specific manner through distal effects on promoter activation rather than proximal receptor activation and signal transduction.

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