scholarly journals Overexpression of Calreticulin Promotes Cardiac Fibroblasts Activation Via Regulating IRE1 Pathway

Author(s):  
liu zhiyue ◽  
Zhiyue Liu ◽  
Wen Zhang ◽  
Junli Li ◽  
Lei Xiao ◽  
...  

Abstract Calreticulin (CRT) is an endoplasmic reticulum (ER) chaperone involved in cardiac fibroblasts (CFs) activation. It has been reported that the expression of CRT increased in the process of CFs activation. However, the role of CRT in CFs activation and the mechanism is not yet fully elucidated. Therefore, we aimed to verify whether CRT was involved in CFs activation and the possible mechanism underlying this process. We found that CRT protein level was elevated in AngⅡ-induced CFs activation. Knocking down CRT by its siRNA could decrease the protein expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and transforming growth factor-β (TGF-β), and meanwhile attenuate proliferation and migration ratio of CFs. Moreover, the proliferation and migration rates of CFs were promoted and the expression of CTGF, α-SMA and TGF-β were increased when transfection with high-titer adenovirus of CRT. In AngⅡ-induced CFs, inositol-requiring enzyme 1(IRE-1), one of the main ER pathways, was inhibited through CRT silence and activated through CRT overexpression. Overall, this study demonstrates that CRT overexpression could promote AngⅡ induced-CFs activation by activating IRE1 pathway, which could be a potential target for CFs activation.

2019 ◽  
Vol 316 (3) ◽  
pp. H596-H608 ◽  
Author(s):  
Rachel C. Childers ◽  
Ian Sunyecz ◽  
T. Aaron West ◽  
Mary J. Cismowski ◽  
Pamela A. Lucchesi ◽  
...  

Hemodynamic load regulates cardiac remodeling. In contrast to pressure overload (increased afterload), hearts subjected to volume overload (VO; preload) undergo a distinct pattern of eccentric remodeling, chamber dilation, and decreased extracellular matrix content. Critical profibrotic roles of cardiac fibroblasts (CFs) in postinfarct remodeling and in response to pressure overload have been well established. Little is known about the CF phenotype in response to VO. The present study characterized the phenotype of primary cultures of CFs isolated from hearts subjected to 4 wk of VO induced by an aortocaval fistula. Compared with CFs isolated from sham hearts, VO CFs displayed a “hypofibrotic” phenotype, characterized by a ~50% decrease in the profibrotic phenotypic markers α-smooth muscle actin, connective tissue growth factor, and collagen type I, despite increased levels of profibrotic transforming growth factor-β1 and an intact canonical transforming growth factor-β signaling pathway. Actin filament dynamics were characterized, which regulate the CF phenotype in response to biomechanical signals. Actin polymerization was determined by the relative amounts of G-actin monomers versus F-actin. Compared with sham CFs, VO CFs displayed ~78% less F-actin and an increased G-actin-to-F-actin ratio (G/F ratio). In sham CFs, treatment with the Rho kinase inhibitor Y-27632 to increase the G/F ratio resulted in recapitulation of the hypofibrotic CF phenotype observed in VO CFs. Conversely, treatment of VO CFs with jasplakinolide to decrease the G/F ratio restored a more profibrotic response (>2.5-fold increase in α-smooth muscle actin, connective tissue growth factor, and collagen type I). NEW & NOTEWORTHY The present study is the first to describe a “hypofibrotic” phenotype of cardiac fibroblasts isolated from a volume overload model. Our results suggest that biomechanical regulation of actin microfilament stability and assembly is a critical mediator of cardiac fibroblast phenotypic modulation.


Hereditas ◽  
2021 ◽  
Vol 158 (1) ◽  
Author(s):  
Yuebin Wang ◽  
Huike Yang ◽  
Xian Su ◽  
Anqiang Cao ◽  
Feng Chen ◽  
...  

Abstract Background Asthma is a common chronic respiratory disease that influences 300 million people all over the world. However, the pathogenesis of asthma has not been fully elucidated. It has been reported that transforming growth factor-β (TGF-β) can activate myofibroblasts. Moreover, the fibroblast to myofibroblast transformation (FMT) can be triggered by TGF-β, which is a major mediator of subepithelial fibrosis. Secreted modular calcium-binding protein 2 (SMOC2) is a member of cysteine (SPARC) family and is involved in the progression of multiple diseases. However, its role in asthma remains poorly understood. RT-qPCR evaluated the expression of SMOC2. Bromodeoxyuridine assay and wound-healing assay detected the proliferation and migration of lung fibroblasts, respectively. IF staining was performed to assess the expression of α-smooth muscle actin (α-SMA). Western blot analysis detected the levels of proteins. Flow cytometry was utilized for determination of the number of myofibroblasts. Results We found the expression of SMOC2 was upregulated by the treatment of TGF-β1 in lung fibroblasts. In addition, SMOC2 promoted the proliferation and migration of lung fibroblasts. More importantly, SMOC2 accelerated FMT of lung fibroblasts. Furthermore, SMOC2 was verified to control the activation of AKT and ERK. Rescue assays showed that the inhibition of AKT and ERK pathway reversed the promoting effect of SMOC2 overexpression on proliferation, migration and FMT in lung fibroblasts. Conclusions This work demonstrated that SMOC2 modulated TGF-β1-induced proliferation, migration and FMT in lung fibroblasts and may promote asthma, which potentially provided a novel therapeutic target for the management of asthma.


2020 ◽  
Vol 15 (11) ◽  
pp. 1934578X2097150
Author(s):  
Yung-Jia Chiu ◽  
Kun-Chang Wu ◽  
Jen-Chieh Tsai ◽  
Chun-Pin Kao ◽  
Jung Chao ◽  
...  

The aim of this study was to evaluate the hepatoprotective effects of the fruits of Polygonum orientale L. (POE) against fibrosis in carbon tetrachloride (CCl4)-induced liver injury. Bioactive components of POE were identified using liquid chromatography (LC)-mass spectrometry (MS)/MS by comparison with standards. Treatment with either silymarin (200 mg/kg) or POE (0.5 and 1.0 g/kg) caused significant decreases in the serum levels of enzymes and reduced the extent of liver lesions and fibrosis in histological analysis. POE (0.5 and 1.0 g/kg) decreased the levels of malondialdehyde, nitric oxide, proinflammatory cytokines (ie, tumor necrosis factor-α, interleukin [IL]-1β, and IL-6), an inflammatory cytokine (ie, cyclooxygenase-2), a profibrotic cytokine (ie, transforming growth factor-β), and fibrosis-related proteins (ie, connective tissue growth factor and α-smooth muscle actin) in the liver and enhanced the activities of the antioxidative enzymes superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase. Quantitative analysis of the active constituents in POE revealed an extract composition of 3.4 mg/g of protocatechuic acid, 20.8 mg/g of taxifolin, and 5.6 mg/g of quercetin. We have demonstrated that the hepatoprotective mechanisms of POE are likely to be associated with the decrease in inflammatory cytokines by increasing the activities of antioxidant enzymes. Our findings provide evidence that POE possesses a hepatoprotective activity to ameliorate chronic liver injury.


Cardiology ◽  
2016 ◽  
Vol 134 (3) ◽  
pp. 340-346 ◽  
Author(s):  
Jianquan Zhao ◽  
Han Lei

Background: The proliferation and migration of cardiac fibroblasts are critical for the progress of cardiac fibrosis. Tripartite motif protein 72 (Trim72), also known as MG53, mediates the dynamic process of membrane fusion and exocytosis in striated muscle. However, the role of Trim72 in the proliferation and migration of cardiac fibroblasts is unknown. Methods: In the present study, we used small interference RNA (siRNA) to silence Trim72 and then investigated the effects of Trim72 on cardiac fibroblast proliferation and migration, which were activated during cardiac remodeling after myocardial infarction. Cardiac fibroblasts were isolated from 2- to 3-day-old neonatal Sprague-Dawley rats and transfected with siRNA. A cell-counting assay was used to determine the proliferation of cardiac fibroblasts. A Boyden chamber assay was performed to determine the migration of cardiac fibroblasts. Results: Our study has, for the first time, demonstrated that Trim72 regulates the cell proliferation and migration of rat cardiac fibroblasts. Furthermore, the data from the gene expression profile microarray analysis indicate that Trim72 depletion can cause downregulation of the transforming growth factor (TGF)-β signaling pathway, suggesting that Trim72 regulates the proliferation and migration of cardiac fibroblasts probably via the TGF-β signaling pathway. Conclusions: We have demonstrated that Trim72 might play a pivotal role in the proliferation of neonatal rat cardiac fibroblasts, which could be a potential target for the treatment of cardiac fibrosis. However, the involvement of other signaling pathways and factors in the formation of cardiac fibrosis cannot be excluded.


2021 ◽  
Vol 12 ◽  
Author(s):  
Geer Tian ◽  
Junteng Zhou ◽  
Yue Quan ◽  
Qihang Kong ◽  
Wenchao Wu ◽  
...  

Cardiac fibroblasts (CFs) activation is a hallmark feature of cardiac fibrosis caused by cardiac remodeling. The purinergic signaling molecules have been proven to participate in the activation of CFs. In this study, we explored the expression pattern of P2Y receptor family in the cardiac fibrosis mice model induced by the transverse aortic constriction (TAC) operation and in the activation of CFs triggered by transforming growth factor β1 (TGF-β1) stimulation. We then investigated the role of P2Y1receptor (P2Y1R) in activated CFs. The results showed that among P2Y family members, only P2Y1R was downregulated in the heart tissues of TAC mice. Consistent with our in vivo results, the level of P2Y1R was decreased in the activated CFs, when CFs were treated with TGF-β1. Silencing P2Y1R expression with siP2Y1R accelerated the effects of TGF-β1 on CFs activation. Moreover, the P2Y1R selective antagonist BPTU increased the levels of mRNA and protein of profibrogenic markers, such as connective tissue growth factor (CTGF), periostin (POSTN). periostin (POSTN), and α-smooth muscle actin(α-SMA). Further, MRS2365, the agonist of P2Y1R, ameliorated the activation of CFs and activated the p38 MAPK and ERK signaling pathways. In conclusion , our findings revealed that upregulating of P2Y1R may attenuate the abnormal activation of CFs via the p38 MAPK and ERK signaling pathway.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1628
Author(s):  
Kaj E. C. Blokland ◽  
Habibie Habibie ◽  
Theo Borghuis ◽  
Greta J. Teitsma ◽  
Michael Schuliga ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease with poor survival. Age is a major risk factor, and both alveolar epithelial cells and lung fibroblasts in this disease exhibit features of cellular senescence, a hallmark of ageing. Accumulation of fibrotic extracellular matrix (ECM) is a core feature of IPF and is likely to affect cell function. We hypothesize that aberrant ECM deposition augments fibroblast senescence, creating a perpetuating cycle favouring disease progression. In this study, primary lung fibroblasts were cultured on control and IPF-derived ECM from fibroblasts pretreated with or without profibrotic and prosenescent stimuli, and markers of senescence, fibrosis-associated gene expression and secretion of cytokines were measured. Untreated ECM derived from control or IPF fibroblasts had no effect on the main marker of senescence p16Ink4a and p21Waf1/Cip1. However, the expression of alpha smooth muscle actin (ACTA2) and proteoglycan decorin (DCN) increased in response to IPF-derived ECM. Production of the proinflammatory cytokines C-X-C Motif Chemokine Ligand 8 (CXCL8) by lung fibroblasts was upregulated in response to senescent and profibrotic-derived ECM. Finally, the profibrotic cytokines transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF) were upregulated in response to both senescent- and profibrotic-derived ECM. In summary, ECM deposited by IPF fibroblasts does not induce cellular senescence, while there is upregulation of proinflammatory and profibrotic cytokines and differentiation into a myofibroblast phenotype in response to senescent- and profibrotic-derived ECM, which may contribute to progression of fibrosis in IPF.


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