Abstract 367: Lysyl Oxidase Expression by Cardiac Fibroblasts is Regulated by Integrin-mediated Signaling

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Albert Gao ◽  
Lauren D Black
Keyword(s):  
Gene Expression ◽  
Cardiac Fibrosis ◽  
Lysyl Oxidase ◽  
Cardiac Fibroblasts ◽  
Therapeutic Strategies ◽  
Expression Of Genes ◽  
Adverse Remodeling ◽  
Novel Therapeutic Strategies ◽  
Free Media ◽  
Tgf Β1

Cardiac fibrosis following myocardial infarction (MI) leads to reduced cardiac function, and contributes to heart failure and mortality. Recent studies shown the extent of adverse remodeling may be mitigated by therapeutic strategies which regulate cardiac fibroblast mediated-remodeling. Since cross-linking by lysyl oxidase (LOX) increases following MI and alters the mechanical properties of the infarct, it is critical to characterize how its expression is regulated by CFs post-MI. While LOX expression is attributable to TGF-β1 signaling, we hypothesize that changes in the stiffness and composition of the ECM can also alter LOX expression via integrin-mediated signaling. To investigate this, we isolated CFs from healthy left ventricle (LV) and infarcted cardiac fibroblasts (ICFs) from 1 week post-MI LV and cultured them on tissue culture plastic (TCP) and collagen I-coated plates (COL) in serum-free media for 48 hours to assess the expression of genes associated with LOX signaling, fibrosis, and myofibroblast activation. Our results show an upregulation of LOX gene expression in both CFs and ICFs when cultured on COL and this is further emphasized with the presence of TGF-β1 (Fig. 1A). Gene expression of col1α1, integrin β1 subunit and αSMA (Fig. 1B-D) also exhibit similar upregulation. Ongoing studies will investigate how altered substrate stiffness and composition affect gene expression of LOX and other genes associated with fibrosis. By understanding the effect of the physical microenvironment on the expression of fibrotic genes including LOX, we aim to develop novel therapeutic strategies to attenuate cardiac fibrosis and thus improve cardiac recovery following MI.

scholarly journals Regulation of Gene Expression in Protozoa Parasites

2010 ◽  
Vol 2010 ◽  
pp. 1-24 ◽  
Author(s):  
Consuelo Gomez ◽  
M. Esther Ramirez ◽  
Mercedes Calixto-Galvez ◽  
Olivia Medel ◽  
Mario A. Rodríguez
Keyword(s):  
Gene Expression ◽  
Immune Evasion ◽  
Trichomonas Vaginalis ◽  
Regulation Of Gene Expression ◽  
Therapeutic Strategies ◽  
Control Of Gene Expression ◽  
Expression Of Genes ◽  
Higher Eukaryotes ◽  
Novel Therapeutic Strategies ◽  
Novel Therapeutic

Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression inPlasmodium sp., Trypanosomatids,Entamoeba histolyticaandTrichomonas vaginalis.

Abstract MP259: The Role Of Sertad4 In Pathological Cardiac Remodeling

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Matthew Stratton ◽  
Ashley Francois ◽  
Oscar Bermeo-Blanco ◽  
Alessandro Canella ◽  
Lynn Marcho ◽  
...  
Keyword(s):  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Systolic Function ◽  
Myocardial Infarct ◽  
Proteasome Inhibition ◽  
Rna Seq ◽  
Expression Of Genes ◽  
M Phase ◽  
Tgf Β1

Over 6 million Americans suffer from heart failure (HF) while the 5-year mortality rate following first admission for HF is over 40%. Cardiac fibrosis is a clinical hallmark of HF, regardless of the initiating pathology and is thought to contribute to disease progression. Using an epigenomics discovery approach, we uncovered a nuclear protein, Sertad4, as a potential anti-fibrotic target. Our data indicate that Sertad4 is a positive regulator of fibroblast activation. Specifically, cultured cardiac fibroblast experiments demonstrate that Sertad4 targeting with shRNAs blocks fibroblast proliferation and causes cells to arrest in the G2/M phase of the cell cycle. Also, shRNA targeting of Sertad4 dramatically blocked activation of myofibroblast differentiation genes (αSMA/POSTN/COL1A1). Mechanistically, these effects appear to be mediated by Sertad4 regulation of SMAD2 protein stability in the presence of TGF-β1 stimulation as demonstrated by proteasome inhibition experiments. RNA-seq analysis indicate that Sertad4 also regulates the expression of genes involved in ubiquitination and proteasome degradation. Next, we sought to determine the effect of global Sertad4 knockout on post-myocardial infarct (MI) remodeling and cardiac function in mice. After 4 weeks of permanent LAD ligation, echocardiography was performed to measure systolic function. Relative to wild-type (WT) controls, the Sertad4 KO mice showed preserved systolic function as evident by improved ejection fraction (WT 14.4 +/- 3.6 vs. KO 33.9+/-5.9, p=0.035) and fractional shortening (WT 6.5 +/- 1.7 vs. KO 16.4 +/- 3.4, p=0.046). β-gal staining in the Sertad4/LacZ reporter mouse subjected to MI showed robust Sertad4/LacZ expression in the ischemic scar and boarder-zone with almost no expression in control hearts. This data supports the notion that Sertad4 has a key role in cardiac remodeling in response to ischemic injury.

scholarly journals Improvement of Cardiac Fibrosis Biomarkers through Inflammation Inhibition by Green Tea and Decaffeinated Light Roasted Green Coffee Extract Combination Administration in Metabolic Syndrome Rat Model

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1013
Author(s):  
Mifetika Lukitasari ◽  
Mohammad Saifur Rohman ◽  
Dwi Adi Nugroho ◽  
Nila Aisyah Wahyuni ◽  
Mukhamad Nur Kholis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Syndrome ◽  
Green Tea ◽  
Rat Model ◽  
Cardiac Fibrosis ◽  
Significant Risk ◽  
Green Coffee ◽  
The Metabolic Syndrome ◽  
Tnf Α ◽  
Tgf Β1

Background: Metabolic syndrome is a significant risk factor for cardiovascular diseases. Green tea and green coffee extracts, antioxidant and anti-inflammatory agents may participate in metabolic syndrome-induced cardiac fibrosis alleviation. However, the effect of combination of those extracts still needs exploration. Therefore, this study investigated the effect of green tea and decaffeinated light roasted green coffee extracts and their combination in metabolic syndrome-induced cardiac fibrosis rats. Methods: Metabolic syndrome rat model was i1nduced through high-fat high sucrose diets feeding for 8 weeks and injection of low dose streptozotocin at the 2nd week. The metabolic syndrome rats were divided into 4 experimental groups metabolic syndrome rats (MS); metabolic syndrome rats treated with 300 mg/ kg b.w green tea extract (GT); metabolic syndrome rats treated with 200 mg/ kg b.w decaffeinated light roasted green coffee extract (GC); metabolic syndrome rats treated with the combination of the two extracts (CE); and a normal control (NC) group was added. Angiotensin 2 level was analyzed by ELISA method. Gene expression of NF-κB, TNF-α, IL-6, Tgf-β1, Rac-1, and α-sma were analyzed by touchdown polymerase chain reaction methods. Results: Metabolic syndrome rats treated with green tea and decaffeinated light roasted green coffee significantly decreased angiotensin-2 serum level and cardiac inflammation and fibrosis gene expression level (NF-κB, TNF-α, IL-6, Tgf-β1, Rac-1, and α-sma). More significant alleviation was observed in the combination group. Conclusion: This study suggested that combination of green tea and decaffeinated light roasted green coffee extracts showed better improvement in metabolic syndrome-induced cardiac fibrosis rat model compared to that of single extract administration through inflammation inhibition

scholarly journals Deletion of Osteopontin Enhances b2-Adrenergic Receptor-Dependent Anti-Fibrotic Signaling in Cardiomyocytes

2019 ◽  
Author(s):  
Celina M. Pollard ◽  
Victoria L. Desimine ◽  
Shelby L. Wertz ◽  
Arianna Perez ◽  
Barbara M. Parker ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Adenosine Monophosphate ◽  
Cardiac Cells ◽  
Protein Levels ◽  
Camp Generation ◽  
H9c2 Cardiomyocytes ◽  
Adverse Remodeling ◽  
Cardiac Myoblasts

Cardiac β2-adrenergic receptors (ARs) are known to inhibit collagen production and fibrosis in cardiac fibroblasts and myocytes. The β2AR is a Gs protein-coupled receptor (GPCR) and, upon its activation, stimulates generation of cyclic 3', 5'-adenosine monophosphate (cAMP). cAMP has two effectors: protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac). Epac1 has been shown to inhibit cardiac fibroblast activation and fibrosis. Osteopontin (OPN) is a ubiquitous pro-inflammatory cytokine, mediating also fibrosis in several tissues, including the heart. OPN underlies several cardiovascular pathologies, including atherosclerosis and cardiac adverse remodeling. We have found that the cardiotoxic hormone aldosterone transcriptionally upregulates OPN in H9c2 rat cardiac myoblasts, an effect prevented by endogenous β2AR activation. Additionally, CRISPR-mediated OPN deletion enhances cAMP generation in response to both b1AR and β2AR activation in H9c2 cardiomyocytes, leading to upregulation of Epac1 protein levels. These effects render β2AR stimulation capable of completely abrogating transforming growth factor (TGF)-β-dependent fibrosis in OPN-lacking H9c2 cardiomyocytes. Finally, OPN interacts constitutively with Gas subunits in H9c2 cardiac cells. Thus, we have uncovered a direct inhibitory role of OPN in cardiac β2AR anti-fibrotic signaling via cAMP/Epac1. OPN blockade could be of value in the treatment and/or prevention of cardiac fibrosis.

scholarly journals Bone Morphogenetic Protein 9 Reduces Cardiac Fibrosis and Improves Cardiac Function in Heart Failure

Circulation ◽  
2018 ◽  
Vol 138 (5) ◽  
pp. 513-526 ◽  
Author(s):  
Kevin J. Morine ◽  
Xiaoying Qiao ◽  
Sam York ◽  
Peter S. Natov ◽  
Vikram Paruchuri ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Human Subjects ◽  
Lv Function ◽  
Transverse Aortic Constriction ◽  
Aortic Constriction ◽  
Bone Morphogenetic Protein 9 ◽  
Human Cardiac Fibroblasts ◽  
Tgf Β1

Background: Heart failure is a growing cause of morbidity and mortality worldwide. Transforming growth factor beta (TGF-β1) promotes cardiac fibrosis, but also activates counterregulatory pathways that serve to regulate TGF-β1 activity in heart failure. Bone morphogenetic protein 9 (BMP9) is a member of the TGFβ family of cytokines and signals via the downstream effector protein Smad1. Endoglin is a TGFβ coreceptor that promotes TGF-β1 signaling via Smad3 and binds BMP9 with high affinity. We hypothesized that BMP9 limits cardiac fibrosis by activating Smad1 and attenuating Smad3, and, furthermore, that neutralizing endoglin activity promotes BMP9 activity. Methods: We examined BMP9 expression and signaling in human cardiac fibroblasts and human subjects with heart failure. We used the transverse aortic constriction–induced model of heart failure to evaluate the functional effect of BMP9 signaling on cardiac remodeling. Results: BMP9 expression is increased in the circulation and left ventricle (LV) of human subjects with heart failure and is expressed by cardiac fibroblasts. Next, we observed that BMP9 attenuates type I collagen synthesis in human cardiac fibroblasts using recombinant human BMP9 and a small interfering RNA approach. In BMP9 –/– mice subjected to transverse aortic constriction, loss of BMP9 activity promotes cardiac fibrosis, impairs LV function, and increases LV levels of phosphorylated Smad3 (pSmad3), not pSmad1. In contrast, treatment of wild-type mice subjected to transverse aortic constriction with recombinant BMP9 limits progression of cardiac fibrosis, improves LV function, enhances myocardial capillary density, and increases LV levels of pSmad1, not pSmad3 in comparison with vehicle-treated controls. Because endoglin binds BMP9 with high affinity, we explored the effect of reduced endoglin activity on BMP9 activity. Neutralizing endoglin activity in human cardiac fibroblasts or in wild-type mice subjected to transverse aortic constriction–induced heart failure limits collagen production, increases BMP9 protein levels, and increases levels of pSmad1, not pSmad3. Conclusions: Our results identify a novel functional role for BMP9 as an endogenous inhibitor of cardiac fibrosis attributable to LV pressure overload and further show that treatment with either recombinant BMP9 or disruption of endoglin activity promotes BMP9 activity and limits cardiac fibrosis in heart failure, thereby providing potentially novel therapeutic approaches for patients with heart failure.

scholarly journals Cardiomyocyte Derived miR-328 Promotes Cardiac Fibrosis by Paracrinely Regulating Adjacent Fibroblasts

2018 ◽  
Vol 46 (4) ◽  
pp. 1555-1565 ◽  
Author(s):  
Dandan Zhao ◽  
Cui Li ◽  
He Yan ◽  
Tianyu Li ◽  
Ming Qian ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Left Coronary Artery ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Collagen Deposition ◽  
Paracrine Signaling ◽  
Potential Therapeutic Target ◽  
Transmission Electron ◽  
Elevated Expression ◽  
Tgf Β1

Background/Aims: In our previous study, we demonstrated that elevated expression of miR-328 is a potent determinant of cardiac fibrosis during myocardial infarction (MI). In the present study, histological examination revealed progressive fibrosis in transgenic mice overexpressing cardiomyocyte-specific miR-328. This study investigated whether the transfer of miR-328 from cardiomyocytes (CMs) to cardiac fibroblasts (CFs) in a paracrine manner contributes to myocardial fibrosis. Methods: Myocardial infarction was established by the occlusion of the left coronary artery. Masson’s trichrome staining and collagen assays were used to evaluate the progression of fibrosis. The vesicles and translocation of miR-328 in a co-culture assay system were respectively observed using transmission electron microscopy (TEM) and immunofluorescence staining (IF). Real-time PCR was employed to detect the level of miR-328, Col1α1 and Col3α1. The protein expression of Col1α1, TGF-βRIII, p-smad2/3 (phosphorylated-smad2/3) and TGF-β1 were probed using western blot analysis. Results: Cardiomyocyte-specific miR-328 overexpressing transgenic (TG) mice showed enhanced collagen deposition and provoked cardiac fibrosis by the activation of the TGF-β1 pathway, and this effect was abrogated after knockdown of endogenous miR-328 in mice. Correspondingly, the expression of miR-328 was increased in CFs co-cultured with CMs transfected with miR-328 mimics, likely in a paracrine manner. The cardiomyocyte-mediated augmentation of miR-328 contributes to fibrogenesis in CFs, and this pro-fibrotic effect was reversed after the transfection of miR-328 inhibitor in CFs. Conclusion: A novel molecular mechanism for miR-328 derived from CMs as a paracrine signaling mediator of cardiac fibrogenesis further demonstrates that miR-328 is a potential therapeutic target.

Abstract 268: Strain-specific Cardiac Fibroblast Response to Isoproterenol-induced Cardiac Fibrosis

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Shuin Park ◽  
Sara Ranjbarvaziri ◽  
Fides Lay ◽  
Peng Zhao ◽  
Aldons J Lusis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Expression Profiles ◽  
Inbred Mouse ◽  
Gene Expression Profiles ◽  
Mouse Strains ◽  
Sequencing Analysis ◽  
Different Strains

Fibroblasts are a heterogeneous population of cells that function within the injury response mechanisms across various tissues. Despite their importance in pathophysiology, the effects of different genetic backgrounds on fibroblast contribution to the development of disease has yet to be addressed. It has previously been shown that mice in the Hybrid Mouse Diversity Panel, which consists of 110 inbred mouse strains, display a spectrum in severity of cardiac fibrosis in response to chronic treatment of isoproterenol (ISO). Here, we characterized cardiac fibroblasts (CFbs) from three different mouse strains (C57BL/6J, C3H/HeJ, and KK/HIJ) which exhibited varying degrees of fibrosis after ISO treatment. The select strains of mice underwent sham or ISO treatment via intraperitoneally-implanted osmotic pumps for 21 days. Masson’s Trichrome staining showed significant differences in fibrosis in response to ISO, with KK/HIJ mice demonstrating the highest levels, C3H/HeJ exhibiting milder levels, and C57BL/6J demonstrating little to no fibrosis. When CFbs were isolated and cultured from each strain, the cells demonstrated similar traits at the basal level but responded to ISO stimuli in a strain-specific manner. Likewise, CFbs demonstrated differential behavior and gene expression in vivo in response to ISO. ISO treatment caused CFbs to proliferate similarly across all strains, however, immunofluorescence staining showed differential levels of CFb activation. Additionally, RNA-sequencing analysis revealed unique gene expression profiles of all three strains upon ISO treatment. Our study depicts the phenotypic heterogeneity of CFbs across different strains of mice and our results suggest that ISO-induced cardiac fibrosis is a complex process that is independent of fibroblast proliferation and is mainly driven by the activation/inhibition of genes involved in pro-fibrotic pathways.

Abstract P471: Mechanisms Controlling Regression Of Cardiac Fibrosis By Removal Of Pressure Overload

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Lily Neff ◽  
An Van Laer ◽  
Catalin F Baicu ◽  
Michael R Zile ◽  
Amy Bradshaw
Keyword(s):  
Cardiac Fibrosis ◽  
Volume Fraction ◽  
Lysyl Oxidase ◽  
Cardiac Fibroblasts ◽  
Pressure Overload ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Cellular Mechanisms ◽  
Cross Sectional ◽  
Fibroblast Activation

Background: Antecedent conditions, like aortic stenosis, can induce left ventricular pressure overload (LVPO), that can lead to Heart Failure with Preserved Ejection Fraction (HFpEF). Myocardial fibrosis and stiffness are key characteristics of HFpEF. Cardiac fibroblasts are the primary cell type regulating ECM production and deposition. In previous studies, biopsies isolated at the time of SAVR surgery, to correct stenosis, and then at 1-year and 5-years post-SAVR showed reductions in hypertrophy and fibrosis demonstrating these processes can regress. However, cellular mechanisms, including fibroblast activity, are poorly defined. Objective: Define mechanisms that contribute to remodeling of ECM before and after LVPO. Methods: LVPO was induced using transverse aortic constriction (TAC). LVPO was relieved by removal of the band (unTAC) at 4 wks. Cardiomyocyte cross-sectional area (CSA), collagen volume fraction (CVF), and protein production was measured by histology and immunoblot for five time points: nonTAC, 2wk TAC, 4wk TAC, 4wk TAC+2wk unTAC, and 4wk TAC+4wk unTAC. Results: In response to LVPO, myocyte CSA increased by 23% at 2wk TAC and by 47% at 4wk. CVF increased by 64% and 204% at 2wk and 4wk TAC, respectively, versus nonTAC. In 2wk TAC hearts, SMA, a marker of fibroblast activation was increased as was production of two collagen cross-linking enzymes, lysyl oxidase (LOX) and LOXL2, in the absence of significant increases in markers of ECM degradation. After unloading, myocyte CSA decreased by 20% in 2wk unTAC versus 4wk TAC and CVF decreased by 38% in 4wk unTAC versus 4wk TAC. Coincident with decreases in CVF, levels of pro-MMP2 increased at 2wk unTAC as did levels of degraded collagen measured by collagen hybridizing peptide reactivity. Whereas markers of ECM deposition, LOX and LOXL2, were not increased in unTAC myocardium, a resurgence of SMA production occurred in 2wk unTAC. Conclusions: In LVPO hearts, hypertrophy was characterized by increases in myocyte CSA, greater CVF, and fibroblast activation with increased production of pro-fibrotic ECM. After unloading, hypertrophy and fibrosis significantly decreased accompanied by increases in ECM degrading activity and reductions in proteins that contribute to collagen assembly.

Abstract P107: Hypertension Enhances the Differentiation of Cardiac Fibroblasts Into Myofibroblasts After TGF-beta1 Treatment

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Gianluca L Perrucci ◽  
Maria Corlian!ò ◽  
Delfina Tosi ◽  
Patrizia Nigro ◽  
Gaetano Bulfamante ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Smooth Muscle Actin ◽  
Pcr Analysis ◽  
Alpha Smooth Muscle Actin ◽  
Qrt Pcr ◽  
Gene And Protein Expression

Objectives: In cardiac fibrosis associated with hypertension, TGF-beta1 plays a key role by acting on differentiation of cardiac fibroblasts (CF) into alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts. In this study, we tested the effect of TGF-beta1 during the myofibroblast differentiation process of CF from normotensive and hypertensive rats. Methods: CF were obtained by enzymatic digestion of hearts isolated from Spontaneously Hypertensive (hCF) and normotensive Wistar Kyoto (nCF) rats (n=5 rat/group). Gene and protein expression in CF was evaluated by Western blot and qRT-PCR analyses, respectively. Immunohistochemistry analysis for integrin alpha-v beta-5 was performed on rat cardiac tissue (n=5 rat/group). Results: Cultured hCF showed an enhanced SMAD2/3 activation and alpha-SMA protein expression after treatment with TGF-beta1 (5 ng/ml) in comparison with nCF. Alpha-SMA up-regulation was further confirmed by qRT-PCR analysis that showed a significant increase in alpha-SMA gene expression in hCF after TGF-beta1 treatment (2.78±0.25 vs 2.01±0.21 fold increase, p <0.05). Moreover, immunostaining on cardiac tissues revealed a higher expression of integrin alpha-v beta-5 in hypertensive vs normotensive rat hearts (345.3±170.0 vs 48.2±22.3 mm 2 of integrin-positive area, p <0.05). This result was also confirmed in vitro ; indeed, integrin alpha-v beta-5 gene expression in hCF increased 2.8-fold in basal condition and 5.12-fold after TGF-beta1 treatment when compared to untreated nCF. Conclusions: Taken together, these results suggest that hCF are more prone to upregulate integrin alpha-v beta-5 and consequently differentiate into myofibroblasts in vitro under TGF-beta1 treatment. Thus, targeting alpha-v beta-5 might open a novel prospective for the treatment of fibrosis in hypertensive hearts likely reducing integrin-mediated TGF-beta1 activation.

Abstract 487: Dihyrosphingosine 1 Phosphate Mediates Collagen Synthesis in Cardiac Fibroblasts Throught Pi3k/akt- Mtor Signalling Pathway

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Ruth R Magaye ◽  
Feby Sevira ◽  
Xin Xiong ◽  
Bernard Flynn ◽  
Bing Wang
Keyword(s):  
Gene Expression ◽  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Mtor Pathway ◽  
Neonatal Rat ◽  
Protein Levels ◽  
Proline Incorporation ◽  
Exogenous Addition ◽  
First Time

Background: Cardiac fibrosis is one of the hallmarks of cardiac remodelling in cardiomyopathies such as heart Failure (HF). Dyslipidemia plays a role in the progression of HF. The sphingolipid, dihydrosphingosine 1 phosphate (dhS1P) has been shown to bind to high density lipids in plasma. Unlike its analog, spingosine 1 phosphate (S1P), the role of dhS1P in cardiac fibrosis is not known. The aim of this study is to determine the role dhS1P plays in cardiac fibrosis through the PI3K/Akt- mTOR pathway. Method: Neonatal rat cardiac fibroblasts (NCF) were isolated from 1-2 day old pups with enzymic digestion. After pre-treating with the PI3K inhibitor, Wortmannin (W, 0.1 - 10.0μM), cells were stimulated with dhS1P for 48 hours. NCF collagen synthesis was determined by 3H-proline incorporation. NCF were also treated for protein and gene expression analysis. Results: Exogenous addition of 3 μM dhS1P stimulated significant increase in collagen synthesis (p<0.005) which was dose dependently inhibited by W (p < 0.0001, Fig. 1A). Western blot analysis showed that W reduced Akt, mTOR, and S6 activation in the presence of dhS1P. dhS1P also increased protein levels of TGFβ, Coll 1 and TIMP1. W reduced dhS1P elevated TIMP1, and SK1, but not TGFβ1 gene expression (Fig. 1B). Conclusion: Our study demonstrates for the first time that dhS1P can cause cardiac cellular fibrosis via PI3K/Akt- mTOR pathway. Its inhibition may represent a novel therapeutic strategy for cardiac fibrosis.

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