scholarly journals Cardiac Fibroblasts and Cardiac Fibrosis: Precise Role of Exosomes

Author(s):  
Prabhat Ranjan ◽  
Rajesh Kumari ◽  
Suresh Kumar Verma
2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Elke Dworatzek ◽  
Shokoufeh Mahmoodzadeh ◽  
Sandra Kunze ◽  
Vera Regitz-Zagrosek

Clinical and animal studies showed in female pressure-overloaded hearts less cardiac fibrosis and collagen I and III gene expression compared to males, suggesting an inhibitory effect of 17β-Estradiol (E2) on collagens. Therefore we investigated the role of E2 and estrogen receptors (ER) on collagen I and III expression in isolated rat cardiac fibroblasts from both sexes. Cardiac fibroblasts were isolated from adult male and female Wistar rats, and treated with E2 (10-8M), vehicle, ERα and ERβ-agonist (10-7M) and/or pre-treated with ICI 182,780 (10-5M) for 24h. Cellular localization of ER in cardiac fibroblasts with/without E2 was detected by immunofluorescence staining, and expression of both ER was determined by western blot. Expression of collagen I and III was determined by qRT-PCR and western blot. E2-treatment led to a nuclear translocation of ERα and ERβ in cardiac fibroblasts, suggesting the functional activity of ER as transcription factors. Furthermore in cardiac fibroblasts from female rats E2 led to a significant down-regulation of collagen I and III gene and protein expression. In contrast there was a significant increase of collagen I and III levels in fibroblasts isolated from male rat hearts by E2. E2-effect could be inhibited by ICI 182, 780 indicating the involvement of ER. In cardiac fibroblasts from female rats, ERα-agonist treatment led to a significant down-regulation of collagen I and III mRNA level, but ERβ-agonist had no effects. In contrast, ERβ-agonist treatment of cardiac fibroblasts from males increased collagen I and III mRNA, but no changes with ERα agonist-treatment were detected. ERα protein levels displayed no sex differences at basal level. After E2-treatment ERα protein was up-regulated in male cells, but decreased in cardiac fibroblasts from females. ERβ protein was higher in female cells compared to males, but the expression was not regulated by E2 in both sexes. Sex-specific regulation of collagen I and III expression by E2 in cardiac fibroblasts might be responsible for sex-differences in cardiac fibrosis. This might be due to sexually dimorphic ER expression and regulation. Understanding how E2 and ER mediate sex-differences in cardiac remodeling may help to design sex-specific pharmacological interventions.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Hongmei Peng ◽  
Oscar Carretero ◽  
Xiao-Ping Yang ◽  
Pablo Nakagawa ◽  
Jiang Xu ◽  
...  

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.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10502
Author(s):  
Huan Guo ◽  
Xinke Zhao ◽  
Haixiang Su ◽  
Chengxu Ma ◽  
Kai Liu ◽  
...  

Background Radiation exposure of the thorax is associated with a greatly increased risk of cardiac morbidity and mortality even after several decades of advancement in the field. Although many studies have demonstrated the damaging influence of ionizing radiation on cardiac fibroblast (CF) structure and function, myocardial fibrosis, the molecular mechanism behind this damage is not well understood. miR-21, a small microRNA, promotes the activation of CFs, leading to cardiac fibrosis. miR-21 is overexpressed after irradiation; however, the relationship between increased miR-21 and myocardial fibrosis after irradiation is unclear. This study was conducted to investigate gene expression after radiation-induced CF damage and the role of miR-21 in this process in rats. Methods We sequenced irradiated rat CFs and performed weighted correlation network analysis (WGCNA) combined with differentially expressed gene (DEG) analysis to observe the effect on the expression profile of CF genes after radiation. Results DEG analysis showed that the degree of gene changes increased with the radiation dose. WGCNA revealed three module eigengenes (MEs) associated with 8.5-Gy-radiation—the Yellow, Brown, Blue modules. The three module eigengenes were related to apoptosis, G2/M phase, and cell death and S phase, respectively. By blocking with the cardiac fibrosis miRNA miR-21, we found that miR-21 was associated with G2/M blockade in the cell cycle and was mainly involved in regulating extracellular matrix-related genes, including Grem1, Clu, Gdf15, Ccl7, and Cxcl1. Stem-loop quantitative real-time PCR was performed to verify the expression of these genes. Five genes showed higher expression after 8.5 Gy-radiation in CFs. The target genes of miR-21 predicted online were Gdf15 and Rsad2, which showed much higher expression after treatment with antagomir-miR-21 in 8.5-Gy-irradiated CFs. Thus, miR-21 may play the role of fibrosis and G2/M blockade in regulating Grem1, Clu, Gdf15, Ccl7, Cxcl1, and Rsad2 post-irradiation.


2018 ◽  
Vol 46 (6) ◽  
pp. 2551-2560 ◽  
Author(s):  
LiJun Qian ◽  
Jian Hong ◽  
YanMei Zhang ◽  
MengLin Zhu ◽  
XinChun Wang ◽  
...  

Background/Aims: Cardiac fibrosis is a pathological change leading to cardiac remodeling during the progression of myocardial ischemic diseases, and its therapeutic strategy remains to be explored. S100A4, a calcium-binding protein, participates in fibrotic diseases with an unclear mechanism. This study aimed to investigate the role of S100A4 in cardiac fibrosis. Methods: Cardiac fibroblasts from neonatal C57BL/6 mouse hearts were isolated and cultured. Myocardial infarction was induced by ligating the left anterior descending coronary artery (LAD). The ligation was not performed in the sham group. A volume of 5×105pfu/g adenovirus or 5 µM/g ICG-001 was intramyocardially injected into five parts bordering the infarction zone or normal region. We used Western blotting, quantitative RT-PCR, immunofluorescence, immunohistochemistry and Masson’s trichrome staining to explore the function of S100A4. Results: We found significant increases of S100A4 level and cardiac fibrosis markers, and β-catenin signaling activation in vitro and in vivo. In addition, knockdown of S100A4 significantly reduced cardiac fibrosis and β-catenin levels. Moreover, the expression of S100A4 decreased after ICG-001 inhibited β-catenin signal pathway. Conclusion: Downregulation of S100A4 alleviates cardiac fibrosis via Wnt/β -catenin pathway in mice. S100A4 may be a therapeutic target of cardiac fibrosis.


2018 ◽  
Vol 115 (2) ◽  
pp. 315-327 ◽  
Author(s):  
Elke Dworatzek ◽  
Shokoufeh Mahmoodzadeh ◽  
Cindy Schriever ◽  
Kana Kusumoto ◽  
Lisa Kramer ◽  
...  

Abstract Aims Sex differences in cardiac fibrosis point to the regulatory role of 17β-Estradiol (E2) in cardiac fibroblasts (CF). We, therefore, asked whether male and female CF in rodent and human models are differentially susceptible to E2, and whether this is related to sex-specific activation of estrogen receptor alpha (ERα) and beta (ERβ). Methods and results In female rat CF (rCF), 24 h E2-treatment (10−8  M) led to a significant down-regulation of collagen I and III expression, whereas both collagens were up-regulated in male rCF. E2-induced sex-specific collagen regulation was also detected in human CF, indicating that this regulation is conserved across species. Using specific ERα- and ERβ-agonists (10−7 M) for 24 h, we identified ERα as repressive and ERβ as inducing factor in female and male rCF, respectively. In addition, E2-induced ERα phosphorylation at Ser118 only in female rCF, whereas Ser105 phosphorylation of ERβ was exclusively found in male rCF. Further, in female rCF we found both ER bound to the collagen I and III promoters using chromatin immunoprecipitation assays. In contrast, in male rCF only ERβ bound to both promoters. In engineered connective tissues (ECT) from rCF, collagen I and III mRNA were down-regulated in female ECT and up-regulated in male ECT by E2. This was accompanied by an impaired condensation of female ECT, whereas male ECT showed an increased condensation and stiffness upon E2-treatment, analysed by rheological measurements. Finally, we confirmed the E2-effect on both collagens in an in vivo mouse model with ovariectomy for E2 depletion, E2 substitution, and pressure overload by transverse aortic constriction. Conclusion The mechanism underlying the sex-specific regulation of collagen I and III in the heart appears to involve E2-mediated differential ERα and ERβ signaling in CFs.


2021 ◽  
Author(s):  
Nicholas W. Chavkin ◽  
Soichi Sano ◽  
Ying Wang ◽  
Kosei Oshima ◽  
Hayato Ogawa ◽  
...  

AbstractBackgroundA hallmark of heart failure is cardiac fibrosis, which results from the injury-induced differentiation response of resident fibroblasts to myofibroblasts that deposit extracellular matrix. During myofibroblast differentiation, fibroblasts progress through polarization stages of early pro-inflammation, intermediate proliferation, and late maturation, but the regulators of this progression are poorly understood. Planar cell polarity receptors, receptor tyrosine kinase like orphan receptor 1 and 2 (Ror1/2), can function to promote cell differentiation and transformation. In this study, we investigated the role of the Ror1/2 in a model of heart failure with emphasis on myofibroblast differentiation.Methods and ResultsThe role of Ror1/2 during cardiac myofibroblast differentiation was studied in cell culture models of primary murine cardiac fibroblast activation and in knockout mouse models that underwent transverse aortic constriction (TAC) surgery to induce cardiac injury by pressure overload. Expression of Ror1 and Ror2 were robustly and exclusively induced in fibroblasts in hearts after TAC surgery, and both were rapidly upregulated after early activation of primary murine cardiac fibroblasts in culture. Cultured fibroblasts isolated from Ror1/2-KO mice displayed a pro-inflammatory phenotype indicative of impaired myofibroblast differentiation. Although the combined ablation of Ror1/2 in mice did not result in a detectable baseline phenotype, TAC surgery led to the death of all mice by day 6 that was associated with myocardial hyper-inflammation and vascular leakage.ConclusionsTogether, these results show that Ror1/2 are essential for the progression of myofibroblast differentiation and for the adaptive remodeling of the heart in response to pressure overload.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
O K Choong ◽  
C Y Chen ◽  
J H Lin ◽  
P J Lin ◽  
J H Zhang ◽  
...  

Abstract Noncoding RNAs account for 80% of human transcripts, but functional studies on noncoding RNAs are relatively few and limited. Long noncoding RNAs (lncRNAs) are known to have an important role in cardiac development, and lately, high-throughput RNA sequencing has been extensively utilized to profile and explore the transcriptome landscape of lncRNAs in failing hearts. These studies have revealed that lncRNAs are mostly dysregulated in failing hearts and their expression signature can discriminate failing hearts of different etiologies. H19 is abundantly expressed in failing human hearts and its polymorphism was shown to possess a significant correlation with the risk of coronary artery diseases. In our study using murine hearts, we discovered that H19 was significantly up regulated in the heart after ischemic injury, with predominant expression in cardiac fibroblasts. This finding piqued our interest to further investigate the function of H19 in the heart. We demonstrated that ectopic overexpression of H19 using the AAV approach led to severe cardiac fibrosis in mouse hearts following myocardial infarction. In light of this finding, we generated H19 knockout mice to further investigate the functionality of H19 and we found that cardiac fibrosis was attenuated in these mice. Altogether, these findings suggested that H19 is a fibrosis regulator during cardiac remodeling process after infarction. Due to the multiple regulatory roles of lncRNAs, we then took advantage of chromatin isolation by RNA purification (ChIRP) to identify the H19-interacting protein, YB-1. Surprisingly, mice with YB-1 knockdown displayed severe cardiac fibrosis even without injury. Furthermore, we demonstrated that YB-1 is a transcriptional suppressor of collagen 1A1. Knockout of H19 in YB-1 knockdown partially suppressed Col1a1 expression, which suggests a negative regulatory role of H19 on YB-1 towards the expression of Col1a1. Taking into account all of these findings, we concluded that H19 mediates collagen expression in fibroblasts through the inhibition of YB-1 activity during cardiac remodeling.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Dongchao Lv ◽  
Yihua Bei ◽  
Qiulian Zhou ◽  
Qi Sun ◽  
Tianzhao Xu ◽  
...  

MicroRNAs (miRNAs, miRs), a novel group of small non-coding RNAs, play important roles in cardiac fibrosis. Exercise-induced physiological cardiac growth is associated with hypertrophy and proliferation of cardiomyocytes. In addition, exercise has been shown to inhibit cardiac fibrosis. However, relative little is known about whether exercise could attenuating cardiac fibrosis via targeting miRNA. miR-486 is a muscle enriched miRNAs, however, its role in heart is relative unclear. The current study aimed to investigate the role of miR-486 in exercise-induced cardiac growth in a 3-week swimming training murine model as well as in the function of cardiac fibroblasts and production of extracellular matrix (ECM) using neonatal rat cardiac fibroblasts in primary culture. Our data showed that exercised mice displayed increased about three-fold expression of miR-486 in hearts as measured by microarray analysis and qRT-PCRs. EdU proliferation assays demonstrated that miR-486 mimics decreased (5.90%±0.57% vs 4.02%±0.27% in nc-mimics vs miR-486-mimics, respectively), while miR-486 inhibitor increased the proliferation of cardiac fibroblasts in vitro (5.87%±0.16% vs 9.60%±0.58% in nc-inhibitor vs miR-486-inhibitor, respectively). Although downregulation of miR-486 had no regulatory effect on α-sma and collagen-1 gene expression in cardiac fibroblasts, overexpression of miR-486 significantly reduced the mRNA level of α-sma (1.01±0.08 vs 0.28±0.04 in nc-mimics vs miR-486-mimics, respectively) and collagen-1(1.02±0.12 vs 0.58±0.09 in nc-mimics vs miR-486-mimics, respectively), indicative of attenuated activation of fibroblasts and reduced production of ECM. These data reveal that miR-486 is essentially involved in the proliferation and activation of cardiac fibroblasts, and might be a key regulator mediating the benefit of exercise in preventing cardiac fibrosis.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Malina J Ivey ◽  
Michelle Tallquist

Cardiac fibrosis is a major component of heart disease and is a hallmark of decreased cardiac function. Currently, there are no treatments that attenuate fibrosis directly. This major hurdle can be overcome by targeting the resident fibroblast. Preliminary data demonstrates that loss of PDGFRα expression in the adult cardiac fibroblast lineage results in loss of over half of resident fibroblasts. A time course experiment revealed that in as little as 4 days after PDGFRα gene deletion fibroblast loss can observed. Based on the basal level of fibroblast proliferation (0.8%+/-0.9, i.e. 4 of 398 cells), we hypothesize that PDGFRα signaling is essential for fibroblast maintenance and that fibroblasts undergo rapid turnover. We have begun to elucidate which downstream signals of PDGFRα are involved the different roles of the fibroblast. Using a PDGFRα-dependent-PI3K-deficient mouse model, preliminary data indicates that PDGFRα-dependent PI3K signaling is involved in this cell survival response. Future studies will investigate cardiac fibroblast maintenance signals by determining which cell types secrete PDGF ligands. We will also investigate the role of PDGFRα signaling after myocardial infarction. Our lab has genetic tools that enable us to follow fibroblasts after injury, and we have determined both the number of proliferating fibroblasts at different time points, as well as the fraction of fibroblasts that make up the total population of proliferating cells after LAD ligation. Our preliminary data in control hearts shows that fibroblasts reach their peak of proliferation within a week after infarction, although they remain one of the most proliferative cell types as long as three weeks after induction. Our studies will illuminate the role of the fibroblast in tissue homeostasis and after infarction and identify how these cells contribute to overall cardiovascular function and delineate the fine balance between the essential and detrimental functions of the fibroblast.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Maradumane L Mohan ◽  
Lisa M Grove ◽  
Mitchell A Olman ◽  
Sathyamangla V Naga Prasad

Phosphoinositide 3 Kinase γ (PI3Kγ) belongs to a family of lipid kinases genetic deletion of which leads to pressure overload induced cardiac fibrosis in mice. However, the mechanism by which PI3Kγ mediates cardiac fibrosis is unknown. Cardiac fibrosis is a key underlying cause of fatal heart failure. A well-known fibrogenic mechanism is the generation of myofibroblasts, which are characterized by overexpression of smooth muscle α-actin (αSMA). Myofibroblast is a fibrosis-effector cell that produces pro-fibrotic cytokines and exuberant extracellular matrix that leads to cardiac fibrosis. To evaluate the role of PI3Kγ in fibrotic phenotype, cardiac tissue lysates from 3 months old WT and PI3Kγ null (PI3Kγ -/- ) mice were assessed for the expression of αSMA. Interestingly, there is significant up-regulation of αSMA in PI3Kγ -/- in comparison to littermate controls (WT) even at baseline suggesting that loss of PI3Kγ predisposes the hearts towards fibrosis. To directly confirm that PI3Kγ -/- cardiac fibroblasts (CF) exhibit a myofibroblast phenotype even at baseline, CF were isolated from hearts of WT and PI3Kγ -/- mice and assessed for myofibroblast phenotype by immunostaining for αSMA in stress fibers. Fluorescence microscopy on the CF from PI3Kγ -/- mice showed intense immunostaining for αSMA with greater number of cells exhibiting αSMA in stress fibers when compared to CF from WT mice. Consistently, immunoblotting showed significantly higher αSMA protein levels in PI3Kγ -/- CF compared to WT CF suggesting that PI3Kγ -/- fibroblasts are “primed” to undergo myofibroblast differentiation. To determine the role of kinase-independent function of PI3Kγ in vivo, we generated unique mice lines with cardiomyocyte-specific expression of either kinase-dead PI3Kγ (PI3Kγ inact ) or constitutively active PI3Kγ ( Myr PI3Kγ) in the global PI3Kγ -/- (PI3Kγ inact /PI3Kγ -/- or Myr PI3Kγ/PI3Kγ -/- ) and measured αSMA. Surprisingly, abundance of αSMA protein is significantly reduced in PI3Kγ inact /PI3Kγ -/- when compared to WT and PI3Kγ -/- mice. These data reveal that kinase-independent function of PI3Kγ is a key component in the myocyte-initiated pathway that ultimately drives CF to become myofibroblasts uncovering a novel mechanism of regulating pro-fibrotic signals.


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