scholarly journals The Histamine 3 Receptor Is Expressed in the Heart and Its Activation Opposes Adverse Cardiac Remodeling in the Angiotensin II Mouse Model

2020 ◽  
Vol 21 (24) ◽  
pp. 9757
Author(s):  
Samuel L. McCaffrey ◽  
Grace Lim ◽  
Martyn Bullock ◽  
Ainsley O. Kasparian ◽  
Roderick Clifton-Bligh ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Mouse Model ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Acute Ischemia ◽  
Mouse Heart ◽  
Ang Ii ◽  
Infarct Zone ◽  
Promising Target

Histamine is a basic amine stored in mast cells, with its release capable of activating one of four histamine receptors. The histamine 3 receptor (H3R) is known to be cardioprotective during acute ischemia by acting to limit norepinephrine release. However, a recent study reported that myofibroblasts isolated from the infarct zone of rat hearts responded to H3R activation by up-regulating collagen production. Thus, it is necessary to clarify the potential role of the H3R in relation to fibrosis in the heart. We identified that the mouse left ventricle (LV) expresses the H3R. Isolation of mouse cardiac fibroblasts determined that while angiotensin II (Ang II) increased levels of the H3R, these cells did not produce excess collagen in response to H3R activation. Using the Ang II mouse model of adverse cardiac remodeling, we found that while H3R blockade had little effect on cardiac fibrosis, activation of the H3R reduced cardiac fibrosis and macrophage infiltration. These findings suggest that when activated, the H3R is anti-inflammatory and anti-fibrotic in the mouse heart and may be a promising target for protecting against cardiac fibrosis.

scholarly journals EPRS Regulates Proline-rich Pro-fibrotic Protein Synthesis during Cardiac Fibrosis

2019 ◽  
Author(s):  
Jiangbin Wu ◽  
Kadiam C Venkata Subbaiah ◽  
Li Huitong Xie ◽  
Feng Jiang ◽  
Deanne Mickelsen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Translational Control ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Mrna Translation ◽  
Trna Synthetase ◽  
Mouse Heart ◽  
List Type ◽  
Human And Mouse

AbstractRationaleIncreased protein synthesis of pro-fibrotic genes is a common feature of cardiac fibrosis, a major manifestation of heart failure. Despite this important observation, critical factors and molecular mechanisms for translational control of pro-fibrotic genes during cardiac fibrosis remain unclear.ObjectiveThis study aimed to test the hypothesis that cardiac stress-induced expression of a bifunctional aminoacyl-tRNA synthetase (ARS), glutamyl-prolyl-tRNA synthetase (EPRS), is preferentially required for the translation of proline codon-rich (PRR) pro-fibrotic mRNAs in cardiac fibroblasts during cardiac fibrosis.Methods and ResultsBy analyses of multiple available unbiased large-scale screening datasets of human and mouse heart failure, we have discovered that EPRS acts as an integrated node among all the ARSs in various cardiac pathogenic processes. We confirmed that EPRS was induced at both mRNA and protein level (∼1.5-2.5 fold increase) in failing hearts compared with non-failing hearts using our cohort of human and mouse heart samples. Genetic knockout of one allele of Eprs globally (Eprs+/-) using CRISPR-Cas9 technology or in a myofibroblast-specific manner (Eprsflox/+; PostnMCM/+) strongly reduces cardiac fibrosis (∼50% reduction) in isoproterenol- and transverse aortic constriction-induced heart failure mouse models. Inhibition of EPRS by a prolyl-tRNA synthetase (PRS)-specific inhibitor, halofuginone (Halo), significantly decreased the translation efficiency of proline-rich collagens in cardiac fibroblasts. Furthermore, using transcriptome-wide RNA-Seq and polysome profiling-Seq in Halo-treated fibroblasts, we identified multiple novel Pro-rich genes in addition to collagens, such as Ltbp2 and Sulf1, which are translationally regulated by EPRS. As a major EPRS downstream effector, SULF1 is highly enriched in human and mouse myofibroblast. siRNA-mediated knockdown of SULF1 attenuates cardiac myofibroblast activation and collagen deposition.ConclusionsOur results indicate that EPRS preferentially controls the translational activation of proline codon-rich pro-fibrotic genes in cardiac fibroblasts and augments pathological cardiac remodeling.Novelty and SignificanceWhat is known?TGF-β and IL-11 increase synthesis of pro-fibrotic proteins during cardiac fibrosis.Many pro-fibrotic genes contain Pro genetic codon rich motifs such as collagens.EPRS is an essential house-keeping enzyme required for ligating Pro to tRNAPro for the synthesis of Pro-containing proteins.What New Information Does This Article Contribute?This study is a pioneering investigation of translational control mechanisms of pro-fibrotic gene expression in cardiac fibrosis.EPRS mRNA and protein expression are induced in failing human hearts and mouse hearts undergoing pathological cardiac remodeling.The first demonstration of the in vivo function of EPRS in cardiac remodeling. Heterozygous Eprs global knockout and myofibroblast-specific tamoxifen-inducible Eprs conditional knockout mice show reduced pathological cardiac fibrosis under stress, suggesting that the reduction of EPRS is cardioprotective.Identification of novel preferential translational target genes of EPRS. We found that EPRS regulates translation of Pro-rich (PRR) transcripts, which comprise most of the ECM and secretory signaling molecules. Among those targets, we identified multiple novel PRR genes such as LTBP2 and SULF1.SULF1 is validated as a myofibroblast marker protein in human and mouse heart failure and a potential anti-fibrosis target gene.In cardiac fibroblasts, the synthesis of pro-fibrotic proteins is upregulated by cardiac stressors to activate extracellular matrix deposition and impair cardiac function. In this study, we have discovered an EPRS-PRR gene axis that influences translational homeostasis of pro-fibrotic proteins and promotes pathological cardiac remodeling and fibrosis. EPRS is identified as a common node downstream of multiple cardiac stressors and a novel regulatory factor that facilitates pro-fibrotic mRNA translation in cardiac fibrosis. Global and myofibroblast-specific genetic ablation of EPRS can effectively reduce cardiac fibrosis. This study reveals a novel translational control mechanism that modulates cardiac fibrosis and heart function. Mild inhibition of PRR mRNA translation could be a general therapeutic strategy for the treatment of heart disease. These findings provide novel insights into the translational control mechanisms of cardiac fibrosis and will promote the development of novel therapeutics by inhibiting pro-fibrotic translation factors or their downstream effectors.

Angiotensin II-mediated oxidative stress and procollagen-1 expression in cardiac fibroblasts: blockade by pravastatin and pioglitazone

2006 ◽  
Vol 291 (4) ◽  
pp. H1738-H1745 ◽  
Author(s):  
Jiawei Chen ◽  
Jawahar L. Mehta
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Cardiac Remodeling ◽  
Cardiac Fibroblasts ◽  
Ang Ii ◽  
Mobility Shift ◽  
Positive Interaction ◽  
Mapk Activation ◽  
Variable Effect ◽  
Ppar Γ

Angiotensin II (ANG II), a product of renin-angiotensin system activation, enhances collagen synthesis, which is a key event in cardiac remodeling after myocardial infarction. Inhibition of cardiac remodeling is now a target of multiple therapies, including 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, commonly known as statins, and peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands. We examined the potential antifibrotic effect of the combination of a statin (pravastatin) and a PPAR-γ ligand (pioglitazone) in ANG II-treated mouse cardiac fibroblasts. ANG II treatment induced procollagen-1 expression, which was inhibited by pravastatin and pioglitazone in a dose-dependent fashion. Pretreatment of fibroblasts with low therapeutic concentrations of either pravastatin (0.1 μM) or pioglitazone (5 μM) only slightly decreased ANG II-induced NADPH oxidase expression, superoxide anion production, and procollagen-1 expression; however, the combination of pravastatin and pioglitazone markedly modulated these effects of ANG II. The combination also blocked ANG II-mediated p38 MAPK and p44/42 MAPK activation. Electrophoretic mobility shift assay showed that ANG II activated transcription factors NF-κB and activator protein-1 (AP-1). Although pravastatin and pioglitazone alone had a variable effect on NF-κB and AP-1 activation, their combination exerted a potent inhibitory effect on the activation of both NF-κB and AP-1. The effects of pravastatin and pioglitazone in combination on superoxide generation and procollagen-1 expression mimicked those of α-tocopherol and γ-tocopherol, two potent antioxidants. Thus it appears that there is a positive interaction between pravastatin and pioglitazone in modulating ANG II-mediated oxidative stress, inhibiting MAPK activation, and procollagen-1 expression.

scholarly journals Targeted Ablation of Periostin-Expressing Activated Fibroblasts Prevents Adverse Cardiac Remodeling in Mice

2016 ◽  
Vol 118 (12) ◽  
pp. 1906-1917 ◽  
Author(s):  
Harmandeep Kaur ◽  
Mikito Takefuji ◽  
C.Y. Ngai ◽  
Jorge Carvalho ◽  
Julia Bayer ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Angiotensin Ii ◽  
Cardiac Function ◽  
Single Cell ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Transcriptional Analysis ◽  
Cardiomyocyte Hypertrophy ◽  
Cardiac Damage

Rationale: Activated cardiac fibroblasts (CF) are crucial players in the cardiac damage response; excess fibrosis, however, may result in myocardial stiffening and heart failure development. Inhibition of activated CF has been suggested as a therapeutic strategy in cardiac disease, but whether this truly improves cardiac function is unclear. Objective: To study the effect of CF ablation on cardiac remodeling. Methods and Results: We characterized subgroups of murine CF by single-cell expression analysis and identified periostin as the marker showing the highest correlation to an activated CF phenotype. We generated bacterial artificial chromosome–transgenic mice allowing tamoxifen-inducible Cre expression in periostin-positive cells as well as their diphtheria toxin-mediated ablation. In the healthy heart, periostin expression was restricted to valvular fibroblasts; ablation of this population did not affect cardiac function. After chronic angiotensin II exposure, ablation of activated CF resulted in significantly reduced cardiac fibrosis and improved cardiac function. After myocardial infarction, ablation of periostin-expressing CF resulted in reduced fibrosis without compromising scar stability, and cardiac function was significantly improved. Single-cell transcriptional analysis revealed reduced CF activation but increased expression of prohypertrophic factors in cardiac macrophages and cardiomyocytes, resulting in localized cardiomyocyte hypertrophy. Conclusions: Modulation of the activated CF population is a promising approach to prevent adverse cardiac remodeling in response to angiotensin II and after myocardial infarction.

scholarly journals Krüppel-Like Factor 15 Modulates CXCL1/CXCR2 Signaling-Mediated Inflammatory Response Contributing to Angiotensin II-Induced Cardiac Remodeling

2021 ◽  
Vol 9 ◽  
Author(s):  
Shun He ◽  
Yuanyuan Lu ◽  
Yuetong Guo ◽  
Shijin Li ◽  
Xiao Lu ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Inflammatory Response ◽  
Cardiac Remodeling ◽  
Cardiac Fibroblasts ◽  
Transactivation Domain ◽  
Ang Ii ◽  
Cytokines And Chemokines ◽  
Cardiac Myoblasts ◽  
Signaling Activation

Inflammation is involved in cardiac remodeling. In response to pathological stimuli, activated cardiac fibroblasts (CFs) secreting inflammatory cytokines and chemokines play an important role in monocyte/macrophage recruitment. However, the precise mechanism of CF-mediated inflammatory response in hypertension-induced cardiac remodeling remains unclear. In the present study, we investigated the role of transcription factor Krüppel-like factor 15 (KLF15) in this process. We found that KLF15 expression decreased while chemokine CXCL1 and its receptor CXCR2 expression increased in the hearts of angiotensin II (Ang II)-infused mice. Compared to the wild-type mice, KLF15 knockout (KO) mice aggravated Ang II-induced cardiac hypertrophy and fibrosis. Deficiency of KLF15 promoted macrophage accumulation, increase of CXCL1 and CXCR2 expression, and mTOR, ERK1/2, NF-κB-p65 signaling activation in the hearts. Mechanistically, Ang II dose- dependently decreased KLF15 expression and increased CXCL1 secretion from cardiac fibroblasts but not cardiac myoblasts. Loss- or gain-of-function studies have shown that KLF15 negatively regulated CXCL1 expression through its transactivation domain (TAD). Intriguingly, the adenovirus-mediated full length of KLF15—but not KLF15 with TAD deletion overexpression—markedly prevented pathological change in Ang II-infused mice. Notably, the administration of CXCR2 inhibitor SB265610 reversed KLF15 knockout-mediated aggravation of cardiac dysfunction, remodeling, and inflammation induced by Ang II. In conclusion, our study identifies that KLF15 in cardiac fibroblasts negatively regulates CXCL1/CXCR2 axis-mediated inflammatory response and subsequent cardiac remodeling in hypertension.

scholarly journals FAM114A1 Influences Cardiac Fibrosis by Regulating Angiotensin II Signaling in Cardiac Fibroblasts

2021 ◽  
Author(s):  
Kadiam C Venkata Subbaiah ◽  
Jiangbin Wu ◽  
Wai Hong Wilson Tang ◽  
Peng Yao
Keyword(s):  
Heart Failure ◽  
Angiotensin Ii ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Sequence Similarity ◽  
Ang Ii ◽  
Fibrotic Response ◽  
Genetic Ablation ◽  
Angiotensin Ii Signaling ◽  
Human And Mouse

AbstractCardiac fibrosis, a primary contributor to heart failure (HF) and sudden death, is considered as an important target for HF therapy. However, the signaling pathways that govern cardiac fibroblast (CF) function during cardiac fibrosis have not been fully elucidated. Here, we found that a functionally unannotated human myocardial infarction (MI) associated gene, family with sequence similarity 114 member A1 (FAM114A1), is induced in failing human and mouse hearts compared to non-failing hearts. Homozygous knockout of Fam114a1 (Fam114a1−/−) in the mouse genome reduces cardiac hypertrophy and fibrosis while significantly restores cardiac function in angiotensin (Ang) II- and MI-induced HF mouse models. Fam114a1 deletion antagonizes Ang II induced inflammation and oxidative stress. Using isolated mouse primary CFs in wild type and Fam114a1−/− mice, we found that FAM114A1 is a critical autonomous factor for CF proliferation, activation, and migration. We discovered that FAM114A1 interacts with angiotensin receptor associated protein (AGTRAP) and regulates the expression of angiotensin type 1 receptor (AT1R) and downstream Ang II signaling transduction, and subsequently influences pro-fibrotic response. Using RNA-Seq in mouse primary CFs, we identified differentially expressed genes including extracellular matrix proteins such as Adamts15. RNAi-mediated inactivation of Adamts15 attenuates CF activation and collagen deposition. Our results indicate that FAM114A1 regulates Ang II signaling and downstream pro-fibrotic and pro-inflammatory gene expression, thereby activating cardiac fibroblasts and augmenting pathological cardiac remodeling. These findings provide novel insights into regulation of cardiac fibrosis and identify FAM114A1 as a new therapeutic target for treatment of cardiac disease.SignificanceCardiac fibrosis is a hallmark of heart failure and angiotensin II signaling promotes pro-fibrotic response in the heart. This study is a pioneering investigation of the role of a functionally unknown protein FAM114A1. We show that FAM114A1 expression is induced in human and mouse failing hearts. Genetic ablation of FAM114A1 can effectively reduce cardiac fibrosis and pathological remodeling. Isolated cardiac fibroblasts from Fam114a1 knockout mice show reduced response to Ang II stimulation and compromised myofibroblast activation. Mechanistically, FAM114A1 binds to AGTRAP and influences AT1R protein expression, thereby enhancing angiotensin II signaling and pro-fibrotic response. Thus, FAM114A1 is a novel factor that modulates cardiac fibrosis and pharmacological inhibition of FAM114A1 may be a therapeutic strategy for the treatment of heart disease.

Pharmacological blockage of ICAM-1 improves angiotensin II-induced cardiac remodeling by inhibiting adhesion of LFA-1+ monocytes

2019 ◽  
Vol 317 (6) ◽  
pp. H1301-H1311 ◽  
Author(s):  
Qiu-Yue Lin ◽  
Ping-Ping Lang ◽  
Yun-Long Zhang ◽  
Xiao-Lei Yang ◽  
Yun-Long Xia ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Cardiovascular Diseases ◽  
Adhesion Molecules ◽  
Vascular Endothelium ◽  
Cardiac Remodeling ◽  
Leukocyte Adhesion ◽  
Neutralizing Antibody ◽  
Ang Ii ◽  
Cardiac Contractile ◽  
And Migration

Intercellular adhesion molecule-1 (ICAM-1) is a member of an immunoglobulin-like superfamily of adhesion molecules that mediate leukocyte adhesion to vascular endothelium and are involved in several cardiovascular diseases, including ischemia-reperfusion injury, myocardial infarction, and atherosclerosis. However, the role of ICAM-1 in angiotensin II (ANG II)-induced cardiac remodeling in mice remains unclear. Wild-type mice were administered an IgG control or ICAM-1 neutralizing antibody (1 and 2 mg/mouse, respectively) and ANG II (1,000 ng·kg−1·min−1) for up to 14 days. Cardiac contractile function and structure were detected by echocardiography. Hypertrophy, fibrosis, and inflammation were assessed by histological examination. The infiltration of lymphocyte function-associated antigen-1 (LFA-1+) monocytes/macrophages was assessed by immunostaining. The mRNA expression of genes was evaluated by quantitative RT-PCR analysis. Protein levels were tested by immunoblotting. We found that ICAM-1 expression in ANG II-infused hearts and ICAM-1 levels in serum from human patients with heart failure were significantly increased. Moreover, ANG II infusion markedly enhanced ANG II-induced hypertension, caused cardiac contractile dysfunction, and promoted cardiac hypertrophy, fibrosis, and LFA-1+ macrophage infiltration. Conversely, blockage of ICAM-1 with a neutralizing antibody dose-dependently attenuated these effects. Moreover, our in vitro data further demonstrated that blocking ICAM-1 inhibited ANG II-induced LFA-1+ macrophage adhesion to endothelial cells and migration. In conclusion, these results provide novel evidence that blocking ICAM-1 exerts a protective effect in ANG II-induced cardiac remodeling at least in part through the modulation of adhesion and infiltration of LFA-1+ macrophages in the heart. Inhibition of ICAM-1 may represent a new therapeutic approach for hypertrophic heart diseases. NEW & NOTEWORTHY Leukocyte adhesion to vascular endothelium is a critical step in cardiovascular diseases. ICAM-1 is a member of immunoglobulin-like superfamily of adhesion molecules that binds LFA-1 to mediate leukocytes adhesion and migration. However, the significance of ICAM-1 in ANG II-induced cardiac remodeling remains unclear. This study reveals that blocking of ICAM-1 prevents ANG II-induced cardiac remodeling via modulating adhesion and migration of LFA-1+ monocytes, may serve as a novel therapeutic target for hypertensive cardiac diseases.

Tanshinone IIA Inhibits Angiotensin II-Induced Cell Proliferation in Rat Cardiac Fibroblasts

2011 ◽  
Vol 39 (02) ◽  
pp. 381-394 ◽  
Author(s):  
Paul Chan ◽  
Ju-Chi Liu ◽  
Li-Jen Lin ◽  
Po-Yuan Chen ◽  
Tzu-Hurng Cheng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Proliferation ◽  
Angiotensin Ii ◽  
Cardiac Fibroblasts ◽  
Tanshinone Iia ◽  
No Production ◽  
Ang Ii ◽  
Erk Phosphorylation ◽  
Enos Phosphorylation ◽  
Ros Formation

Tanshinone IIA extracted from Danshen, a popular medicinal herb used in traditional Chinese medicine, exhibits cardio-protective effects. However, the mechanism of its cardioprotective effect is not well established. The aims of this study were to examine whether tanshinone IIA may alter angiotensin II (Ang II)-induced cell proliferation and to identify the putative underlying signaling pathways in rat cardiac fibroblasts. Cultured rat cardiac fibroblasts were pre-treated with tanshinone IIA and stimulated with Ang II, cell proliferation and endothelin-1 (ET-1) expression were examined. The effect of tanshinone IIA on Ang II-induced reactive oxygen species (ROS) formation, and extracellular signal-regulated kinase (ERK) phosphorylation were also examined. In addition, the effect of tanshinone IIA on nitric oxide (NO) production, and endothelial nitric oxide synthase (eNOS) phosphorylation were tested to elucidate the intracellular mechanism. The increased cell proliferation and ET-1 expression by Ang II (100 nM) were partially inhibited by tanshinone IIA. Tanshinone IIA also inhibited Ang II-increased ROS formation, and ERK phosphorylation. In addition, tanshinone IIA was found to increase the NO generation, and eNOS phosphorylation. NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, and the short interfering RNA transfection for eNOS markedly attenuated the inhibitory effect of tanshinone IIA on Ang II-induced cell proliferation. The results suggest that tanshinone IIA prevents cardiac fibroblast proliferation by interfering with the generation of ROS and involves the activation of the eNOS-NO pathway.

Novel targets of ANG II regulation in mouse heart identified by serial analysis of gene expression

2004 ◽  
Vol 287 (5) ◽  
pp. H1957-H1966 ◽  
Author(s):  
Faina Schwartz ◽  
Arvi Duka ◽  
Irena Duka ◽  
Jing Cui ◽  
Haralambos Gavras
Keyword(s):  
Gene Expression ◽  
Cardiac Remodeling ◽  
Unknown Function ◽  
Mouse Heart ◽  
Ang Ii ◽  
Coordinate Regulation ◽  
Transcriptional Changes ◽  
Novel Targets ◽  
Molecular Circuitry

Although the central role of ANG II in cardiovascular homeostasis is well appreciated, the molecular circuitry of its many actions is not completely understood. With the use of serial analysis of gene expression to assess global transcriptional changes in the heart of mice after continuous 7-day ANG II administration, we identified patterns of gene expression indicative of cardiac remodeling, including coordinate regulation of genes previously described in a context of processes associated with hypertrophy and fibrosis. In addition, we discovered several novel ANG II targets, including characterized genes of known function, recently annotated genes of unknown function, and the putative genes not yet present in current databases. The serial analysis of gene expression approach to assess the role of ANG II presented in this report provides new venues for inquiries into ANG II-mediated cardiac function.

Abstract 445: A Pro-Fibrotic Role of Interleukin-4 in Cardiac Remodeling and Dysfunction

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Hongmei Peng ◽  
Oscar Carretero ◽  
Xiao-Ping Yang ◽  
Pablo Nakagawa ◽  
Jiang Xu ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Interleukin 4 ◽  
Ang Ii ◽  
Collagen Production ◽  
And Function ◽  
First Time ◽  
Mini Pump

Elevated interleukin-4 (IL-4) levels are positively related to cardiac fibrosis in heart failure and hypertension. Using Balb/c exhibiting high circulating IL-4, Balb/c- Il4 tm2Nnt (IL-4 knockout with Balb/c background, IL-4 -/- ) and C57BL/6 mice, as well as cultured cardiac fibroblasts (CFs), we hypothesized that 1) high levels of IL-4 result in cardiac fibrosis, making the heart susceptible to angiotensin II (Ang II)-induced damage, and 2) IL-4 potently stimulates collagen production by CFs. Each strain (9- to 12-week old male) received vehicle or Ang II (1.4 mg/kg/day, s.c. via osmotic mini-pump) for 8 weeks. Cardiac fibrosis and function were determined by histology and echocardiography, respectively. Compared to C57BL/6, Balb/c mice had doubled interstitial collagen in the heart, enlarged left ventricle and decreased cardiac function along with elevated cardiac IL-4 protein (1.00±0.08 in C57BL/6 vs 2.61±0.46 in Balb/c, p <0.05); all those changes were significantly attenuated in IL-4 -/- (Table 1). Ang II further deteriorated cardiac fibrosis and dysfunction in Balb/c; these detrimental effects were attenuated in IL-4 -/- , although the three strains had a similar level of hypertension. In vitro study revealed that IL-4Rα was constitutively expressed in CFs (Western blot), and IL-4 potently stimulated collagen production by CFs (hydroxproline assay, from 18.89±0.85 to 38.81±3.61 μg/mg at 10 ng/ml, p <0.01). Our study demonstrates for the first time that IL-4, as a potent pro-fibrotic cytokine in the heart, contributes to cardiac fibrotic remodeling and dysfunction. Thus IL-4 may be a potential therapeutic target for cardiac fibrosis and dysfunction.

Abstract 478: FGF23 Expression in Cardiac Fibroblasts Is Augmented by S100/Calgranulins-Mediated Inflammation and Associated With Cardiac Hypertrophy, but Not in Angiotensin II-Induced Cardiac Hypertrophy

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Marion Hofmann Bowman ◽  
Brandon Gardner ◽  
Judy Earley ◽  
Debra L Rateri ◽  
Alan Daugherty ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Cardiac Hypertrophy ◽  
Cardiac Fibroblasts ◽  
Left Ventricular ◽  
Heart Weight ◽  
Ang Ii ◽  
Wild Type ◽  
Wild Type Littermate ◽  
Transgenic Expression ◽  
Significant Difference

Background: Serum S100A12 and fibroblast growth factor (FGF) 23 are biomarkers for cardiovascular mortality in patients with chronic kidney disease (CKD) and are associated with left ventricular hypertrophy (LVH). FGF23 is induced in cultured cardiac fibroblasts in response to cytokines including IL-6, TNF-a, LPS and S100/calgranulins. Moreover, hBAC-S100 transgenic mice with CKD had increased FGF23 in valvular interstitial cells and exhibited LVH. The present study was designed to examine cardiac FGF23 expression in other murine models of LVH in the absence of CKD. Methods: Hearts from five groups of male mice were studied: (i) C57BL6/J with transgenic expression a bacterial artificial chromosome of the human S100/calgranulins (S1008/9 and S100A12, hBAC-S100), (ii) wild type littermates, (iii) LDLR-/- infused with saline (29 days, 0.9%), (iv) LDLR-/- infused with angiotensin (Ang) II (29 days, 1000 ng/kg/min), and (v) fibroblast specific depletion of angiotensin II type 1a receptor (AT1aR) (S100A4-Cre x AT1aR-/- x LDLR-/-) infused with AngII. Results: hBAC-S100, but not wild type littermate mice, developed significant LVH at 10 months by heart weight/body weight (5.9 ±1.1 mg/g vs. 4.2 ±0.8, p<0.04), decreased E/A ratio, and increased LVPW thickness, and associated with increased expression of FGF23 mRNA and protein in cardiac tissue lysates (2-4 fold increase). Similarly, Ang II induced significant LVH compared to saline infused LDLR-/- mice (6.1±1.3 vs. 3.6 ±0.9 mg/g, p<0.01), and associated with increased mRNA for hypertrophic genes (ANP, BNP, b-MHC, CTGF and Col1a1). However, there was no significant difference in FGF23 mRNA and protein between Ang II and saline infused mice. Cardiac hypertrophy was attenuated in AngII-infused mice with deficiency of AT1aR (S100A4-Cre+/-xAT1aRxLDLR-/-). In vitro, Ang II (100nM) did not induce FGF23 in valvular interstitial fibroblasts or myocytes. Summary: Transgenic expression of S100/calgranulins is sufficient to induce LVH in aged mice with normal renal function, and this is associated with FGF23 expression in cardiac interstitial fibroblasts. Future studies are needed to determine whether cardiac FGF23 promotes LVH in a paracrine manner. However, FGF23 does not play a role in Ang II-induced LVH.

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