Notum protects against myocardial infarction-induced heart dysfunction by alleviating cardiac fibrosis

Background and Objective:Cardiac fibrosis is a pathological reparative process that follows myocardial infarctionand is associated with compromised cardiac systolic and reduced cardiac compliance.The Wnt signaling pathway is closely implicated in organ fibrosis,and Notum,a highly conserved secreted inhibitor,modulates Wnt signaling.The objective of this study was to explore the role and mechanism of Notum in cardiac fibrosis.Methods:A mouse model of cardiac remodeling was established through left coronary artery ligation surgery,with the addition of Notum injection following myocardial infarction surgery.The protective effect of Notum on myocardial infarction was assessed by evaluating cardiac function,including survival rate,echocardiographic assessment,and cardiac contraction analyses.Inflammatory cell necrosis and infiltration were confirmed through H&E and Masson staining.The expression of fibrosis-related genes andβ-catenin pathway markers was detected using Western blot quantificational RT-PCR(qRT-PCR).Additionally,EdU,wound healing,and immunofluorescence staining analyses were performed to detect the effect of Notum's in transforming growth factor beta-1(TGF-β1)induced myofibroblast transformation.Results:The administration of Notum treatment resulted in enhanced survival rates,improved cardiac function,and decreased necrosis and infiltration of inflammatory cells in mice subjected to left coronary artery ligation.Furthermore,Notum effectively impeded the senescence of cardiac fibroblasts and hindered their pathological transformation into cardiac fibroblasts.Additionally,it significantly reduced collagen production and attenuated the activation of the Wnt/β-catenin pathway.Our preliminary investigations successfully demonstrated the therapeutic potential of Notum in both fibroblasts in vitro and in a mouse model of myocardial infarction-induced cardiac fibrosis in vivo.Conclusion:Notum inhibition of the Wnt/β-catenin signaling pathway and cardiac fibroblast senescence ultimately hampers the onset of cardiac fibrosis.Our findings suggest that Notum could represent a new therapeutic strategy for the treatment of cardiac fibrosis.

Exercise training attenuates angiotensinⅡ-induced cardiac fibrosis by reducing POU2F1 expression

Background:Exercise training protects against heart failure.However,the mechanism underlying the protective effect of exercise training on angiotensinⅡ(AngⅡ)-induced cardiac fibrosis remains unclear.Methods:An exercise model involving C57BL/6N mice and 6 weeks of treadmill training was used.AngⅡ(1.44 mg/kg/day)was administered to induce cardiac fibrosis.RNA sequencing and bioinformatic analysis were used to identify the key factors mediating the effects of exercise training on cardiac fibrosis.Primary adult mouse cardiac fibroblasts(CFs)were used in vitro.Adeno-associated virus serotype 9 was used to overexpress POU domain,class 2,transcription factor 1(POU2F1)in vivo.Results:Exercise training attenuated AngⅡ-induced cardiac fibrosis and reversed 39 gene expression changes.The transcription factor regulating the largest number of these genes was POU2F1.Compared to controls,POU2F1 was shown to be signififcantly upregulated by AngⅡ,which is itself reduced by exercise training.In vivo,POU2F1 overexpression nullified the benefits of exercise training on cardiac fibrosis.In CFs,POU2F1 promoted cardiac fibrosis.CCAAT enhancer-binding proteinβ(C/EBPβ)was predicted to be the transcription factor of POU2F1and verified using a dual-luciferase reporter assay.In vivo,exercise training activated AMP-activated protein kinase(AMPK)and alleviated the increase in C/EBPβinduced by AngⅡ.In CFs,AMPK agonist inhibited the increase in C/EBPβand POU2F1 induced by Ang II,whereas AMPK inhibitor reversed this effect.Conclusion:Exercise training attenuates AngⅡ-induced cardiac fibrosis by reducing POU2F1.Exercise training inhibits POU2F1 by activating AMPK,which is followed by the downregulation of C/EBPβ,the transcription factor of POU2F1.

Relaxin Inhibit Cardiac Fibrosis Induced by Phorbol 12-myristate 13-acetate

Relaxin is known to inhibit cardiac fibrosis. However, it is unclear whether relaxin could regulate the effects of Phorbol 12-myristate 13-acetate （PMA, PKC activator） on cardiac fibrosis. So the influence of relaxin on the cell proliferation and collagen expression induced by PMA in cultured cardiac fibroblasts was studied. It showed that PMA significantly increased cardiac fibroblasts proliferation, Type I pro-collagen protein expression, Type I pro-collagen mRNA expression, and rhRLX absolutely significantly decreased PMA induced effects on cardiac fibroblasts proliferation and Type I pro-collagen expressions, indicating that relaxin could inhibit cardiac fibrosis induced by PMA.

Cryptotanshinone attenuates isoprenaline-induced cardiac fibrosis in the mouse associated with upregulation and activation of matrix metalloproteinase-2

Objectives The impairment of matrix metallopro- teinase-2(MMP-2)has been associated with the development of cardiac fibrosis.Although the Chinese herb Salvia miltior-rhiza has been widely used in patients with cardiovascular disorders,the mechanisms involved have not been elucidated. The purpose of the present study was to determine whether the administration of cryptotanshinone,an active ingredient of Salvia miltiorrhiza,could prevent the cardiac fibrosis induced by isoprenaline and to investigate the underlying mechanisms. Methods and Results Male C57BL/6 mice were submitted to receive daily injection of 0.9%saline,3 mg/kg isoprenaline, or isoprenaline plus 20 mg/kg cryptotanshinone by gastric gavage for 2 weeks.Herein,we demonstrate that cryptotanshinone can significantly ameliorate the isoprenaline-induced cardiac fibrosis,which was associated with marked up-regulation and activation of MMP-2 in ventricular myocardium. Additionally,we demonstrate that cryptotanshinone can dose-dependently upregulate and activate MMP-2 in cultured cardiac fibroblast.Moreover,incubation with cryptotanshinone also can prevent isoprenaline-induced downregulation and inactivation of MMP-2 in cultured cardiac fibroblast. Conclusions Taken together,our data suggest that cryptotanshinone may become a novel and potent antifibrotic agent. The present findings might further our understanding of the role of MMP-2 in cardiac fibrosis and antifibrotic mechanisms of cryptotanshinone.

T-2 toxin induces cardiac fibrosis by causing metabolic disorders and up-regulating Sirt3/FoxO3α/MnSOD signaling pathway-mediated oxidative stress

T-2 toxin,an omnipresent environmental contaminant,poses a serious risk to the health of humans and animals due to its pronounced cardiotoxicity.This study aimed to elucidate the molecular mechanism of cardiac tissue damage by T-2 toxin.Twenty-four male Sprague-Dawley rats were orally administered T-2 toxin through gavage for 12 weeks at the dose of 0,10,and 100 nanograms per gram body weight per day(ng/(g·day)),respectively.Morphological,pathological,and ultrastructural alterations in cardiac tissue were meticulously examined.Non-targeted metabolomics analysis was employed to analyze alterations in cardiac metabolites.The expression of the Sirt3/FoxO3α/MnSOD signaling pathway and the level of oxidative stress markers were detected.The results showed that exposure to T-2 toxin elicited myocardial tissue disorders,interstitial hemorrhage,capillary dilation,and fibrotic damage.Mitochondria were markedly impaired,including swelling,fusion,matrix degradation,and membrane damage.Metabonomics analysis unveiled that T-2 toxin could cause alterations in cardiacmetabolic profiles as well as in the Sirt3/FoxO3α/MnSOD signaling pathway.T-2 toxin could inhibit the expressions of the signaling pathway and elevate the level of oxidative stress.In conclusion,the T-2 toxin probably induces cardiac fibrotic impairment by affecting amino acid and choline metabolism as well as up-regulating oxidative stress mediated by the Sirt3/FoxO3α/MnSOD signaling pathway.This study is expected to provide targets for preventing and treating T-2 toxin-induced cardiac fibrotic injury.

m^(6)A reader YTHDF1 promotes cardiac fibrosis by enhancing AXL translation

Cardiac fibrosis caused by ventricular remodeling and dysfunction such as post-myocardial infarction(MI)can lead to heart failure.RNA N6-methyladenosine(m^(6)A)methylation has been shown to play a pivotal role in the occurrence and development of many illnesses.In investigating the biological function of the m^(6)A reader YTHDF1 in cardiac fibrosis,adeno-associated virus 9 was used to knock down or overexpress the YTHDF1 gene in mouse hearts,and MI surgery in vivo and transforming growth factor-β(TGF-β)-activated cardiac fibroblasts in vitro were performed to establish fibrosis models.Our results demonstrated that silencing YTHDF1 in mouse hearts can significantly restore impaired cardiac function and attenuate myocardial fibrosis,whereas YTHDF1 overexpression could further enhance cardiac dysfunction and aggravate the occurrence of ventricular pathological remodeling and fibrotic development.Mechanistically,zinc finger BED-type containing 6 mediated the transcriptional function of the YTHDF1 gene promoter.YTHDF1 augmented AXL translation and activated the TGF-β-Smad2/3 signaling pathway,thereby aggravating the occurrence and development of cardiac dysfunction and myocardial fibrosis.Consistently,our data indicated that YTHDF1 was involved in activation,proliferation,and migration to participate in cardiac fibrosis in vitro.Our results revealed that YTHDF1 could serve as a potential therapeutic target for myocardial fibrosis.

Isoproterenol mechanisms in inducing myocardial fibrosis and its application as an experimental model for the evaluation of therapeutic potential of phytochemicals and pharmaceuticals

Cardiac injury initiates repair mechanisms and results in cardiac remodeling and fi-brosis,which appears to be a leading cause of cardiovascular diseases.Cardiac fi-brosis is characterized by the accumulation of extracellular matrix proteins,mainly collagen in the cardiac interstitium.Many experimental studies have demonstrated that fibrotic injury in the heart is reversible;therefore,it is vital to understand differ-ent molecular mechanisms that are involved in the initiation,progression,and resolu-tion of cardiac fibrosis to enable the development of antifibrotic agents.Of the many experimental models,one of the recent models that has gained renewed interest is isoproterenol(ISP)-induced cardiac fibrosis.ISP is a synthetic catecholamine,sympa-thomimetic,and nonselectiveβ-adrenergic receptor agonist.The overstimulated and sustained activation ofβ-adrenergic receptors has been reported to induce biochemi-cal and physiological alterations and ultimately result in cardiac remodeling.ISP has been used for decades to induce acute myocardial infarction.However,the use of low doses and chronic administration of ISP have been shown to induce cardiac fibrosis;this practice has increased in recent years.Intraperitoneal or subcutaneous ISP has been widely used in preclinical studies to induce cardiac remodeling manifested by fibrosis and hypertrophy.The induced oxidative stress with subsequent perturbations in cellular signaling cascades through triggering the release of free radicals is consid-ered the initiating mechanism of myocardial fibrosis.ISP is consistently used to induce fibrosis in laboratory animals and in cardiomyocytes isolated from animals.In recent years,numerous phytochemicals and synthetic molecules have been evaluated in ISP-induced cardiac fibrosis.The present review exclusively provides a comprehensive summary of the pathological biochemical,histological,and molecular mechanisms of ISP in inducing cardiac fibrosis and hypertrophy.It also summarizes the application of this experimental model in the therapeutic evaluation of natural as well as syn-thetic compounds to demonstrate their potential in mitigating myocardial fibrosis and hypertrophy.

Huoxin Pill(活心丸)Attenuates Cardiac Fibrosis by Suppressing TGF-β1/Smad2/3 Pathway in Isoproterenol-Induced Heart Failure Rats

Objective:To evaluate the effects of Huoxin Pill(活心丸,HXP)on cardiac fibrosis and heart failure(HF)in isoproterenol(ISO)-induced HF rats.Methods:Thirty Wistar rats were randomly divided into 5 groups including control,HF,isosorbide mononitrate(ISMN),HXP low(HXP-L),and HXP high(HXP-H)groups(n=6 for each group)according to the complete randomization method.Rats were pretreated with ISMN(5 mg/kg daily),low concentration of HXP(10 mg/kg daily)or high concentration of HXP(30 mg/kg daily)or equal volume of saline by intragastric administration for 1 week,followed by intraperitoneal injection of ISO(10 mg/kg,14 days),and continually intragastric administrated with above medicines or saline for additional 6 weeks.The effects of HXP treatment on the cardiac function,heart weight index(HWI),pathological changes,and collagen content were further assessed.Moreover,the role of HXP on activation of transforming growth factor-β1(TGF-β1)/Smads pathway was further explored using immunohistochemistry(IHC)and Westernblot assay.Results:HXP treatment significantly alleviated the decrease of ejection fraction(EF)and fractional shortening(FS),while decreased the elevation of left ventricular end-systolic volume(LVESV)in ISO-induced HF rats(P<0.05).Moreover,HXP treatment obviously attenuated the increase of HWI and serum level of creatine kinase MB(CK-MB,P<0.05),as well as pathological changes in ISO-induced HF rats.Further determination indicated that HXP treatment alleviated the elevation of collagenⅠand collagenⅢprotein expression in cardiac tissues of ISO-induced HF rats.Furthermore,HXP treatment significantly down-regulated the increase of TGF-β1 and p-Smad2/3 protein expression in cardiac tissues of HF rats(P<0.05),while did not affect the expression of total Smad2/3.Conclusions:HXP attenuated heart failure and cardiac fibrosis in ISO-induced HF rats by suppression of TGF-β1/Smad2/3 pathway.

Cardiac fibroblast heat shock protein 47 aggravates cardiac fibrosis post myocardial ischemia-reperfusion injury by encouraging ubiquitin specific peptidase 10 dependent Smad4 deubiquitination

Despite complications were significantly reduced due to the popularity of percutaneous coronary intervention(PCI) in clinical trials, reperfusion injury and chronic cardiac remodeling significantly contribute to poor prognosis and rehabilitation in AMI patients. We revealed the effects of HSP47 on myocardial ischemia-reperfusion injury(IRI) and shed light on the underlying molecular mechanism.We generated adult mice with lentivirus-mediated or miRNA(mi1/133TS)-aided cardiac fibroblastselective HSP47 overexpression. Myocardial IRI was induced by 45-min occlusion of the left anterior descending(LAD) artery followed by 24 h reperfusion in mice, while ischemia-mediated cardiac remodeling was induced by four weeks of reperfusion. Also, the role of HSP47 in fibrogenesis was evaluated in cardiac fibroblasts following hypoxia-reoxygenation(HR). Extensive HSP47 was observed in murine infarcted hearts, human ischemic hearts, and cardiac fibroblasts and accelerated oxidative stress and apoptosis after myocardial IRI. Cardiac fibroblast-selective HSP47 overexpression exacerbated cardiac dysfunction caused by chronic myocardial IRI and presented deteriorative fibrosis and cell proliferation.HSP47 upregulation in cardiac fibroblasts promoted TGFβ1-Smad4 pathway activation and Smad4 deubiquitination by recruiting ubiquitin-specific peptidase 10(USP10) in fibroblasts. However, cardiac fibroblast specific USP10 deficiency abolished HSP47-mediated fibrogenesis in hearts. Moreover, blockage of HSP47 with Col003 disturbed fibrogenesis in fibroblasts following HR. Altogether, cardiac fibroblast HSP47 aggravates fibrosis post-myocardial IRI by enhancing USP10-dependent Smad4 deubiquitination,which provided a potential strategy for myocardial IRI and cardiac remodeling.

LncRNA CFAR promotes cardiac fibrosis via the miR-449a-5p/LOXL3/mTOR axis

Cardiac fibrosis is one of the crucial pathological factors in the heart,and various cardiac conditions associated with excessive fibrosis can eventually lead to heart failure.However,the exact molecular mechanism of cardiac fibrosis remains unclear.In the present study,we show that a novel lnc RNA that we named cardiac fibrosis-associated regulator(CFAR)is a profibrotic factor in the heart.CFAR was upregulated in cardiac fibrosis and its knockdown attenuated the expression of fibrotic marker genes and the proliferation of cardiac fibroblasts,thereby ameliorating cardiac fibrosis.Moreover,CFAR acted as a ce RNA sponge for mi R-449a-5p and derepressed the expression of LOXL3,which we experimentally established as a target gene of mi R-449a-5p.In contrast to CFAR,mi R-449a-5p was found to be significantly downregulated in cardiac fibrosis,and artificial knockdown of mi R-449a-5p exacerbated fibrogenesis,whereas overexpression of mi R-449a-5p impeded fibrogenesis.Furthermore,we found that LOXL3 mimicked the fibrotic factor TGF-β1 to promote cardiac fibrosis by activating m TOR.Collectively,our study established CFAR as a new profibrotic factor acting through a novel mi R-449a-5p/LOXL3/m TOR axis in the heart and therefore might be considered as a potential molecular target for the treatment of cardiac fibrosis and associated heart diseases.

Direct intercellular communications dominate the interaction between adipose-derived MSCs and myofibroblasts aqainst cardiac fibrosis

The onset of cardiac fibrosis post myocardial infarction greatly impairs the function of heart. Recent advances of cell transplantation showed great benefits to restore myocardial function, among which the mesenchymal stem cells （MSCs） has gained much attention. However, the underlying cellular mechanisms of MSC therapy are still not fully understood. Although paracrine effects of MSCs on residual cardiomyocytes have been discussed, the amelioration of fibrosis was rarely studied as the hostile environment cannot support the survival of most cell populations and impairs the diffusion of soluble factors. Here in order to decipher the potential mecha- nism of MSC therapy for cardiac fibrosis, we investi- gated the interplay between MSCs and cardiac myofibroblasts （mFBs） using interactive co-culture method, with comparison to paracrine approaches, namely treatment by MSC conditioned medium and gap co-culture method. Various fibrotic features of mFBs were analyzed and the most prominent anti-fibrosis effects were always obtained using direct co-culture that allowed cell-to-cell contacts. Hepatocyte growth factor （HGF）, a well-known anti-fibrosis factor, was demonstrated to be a major contributor for MSCs＇ anti-fibrosisfunction. Moreover, physical contacts and tube-like structures between MSCs and mFBs were observed by live cell imaging and TEM which demonstrate the direct cellular interactions.

Chronic inhibition of cyclic guanosine monophosphate-specific phosphodiesterase 5 prevented cardiac fibrosis through inhibi- tion of transforming growth factor 13-induced Smad signaling

Recent evidences suggested that cyclic guanosine monophosphate-specific phosphodiesterase 5 （PDE5） inhibitor represents an important therapeutic target for cardiovascular diseases. Whether and how it ameliorates cardiac fibrosis, a major cause of diastolic dysfunction and heart failure, is unknown. The purpose of this study was to investigate the effects of PDE5 inhibitor on cardiac fibrosis. We assessed cardiac fibrosis and pathology in mice subjected to transverse aortic constriction （TAC）. Oral sildenafil, a PDE5 inhibitor, was administered in the therapy group. In control mice, 4 weeks of TAC induced significant cardiac dysfunction, cardiac fibrosis, and cardiac fibroblast activation （proliferation and transformation to myofibroblasts）. Sildenafil treatment markedly prevented TAC-induced cardiac dysfunction, cardiac fibrosis and cardiac fibroblast activation but did not block TAC-induced transforming growth factor-β0 （TGF-β1） production and phosphorylation of Smad2/3. In isolated cardiac fibroblasts, sildenafil blocked TGF-β1-induced cardiac fibroblast transformation, proliferation and collagen synthesis. Furthermore, we found that sildenafil induced phosphorylated cAMP response element binding protein （CREB） and reduced CREB-binding protein 1 （CBP1） recruitment to Smad transcriptional complexes. PDE5 inhibition prevents cardiac fibrosis by reducing CBP1 recruitment to Smad transcriptional complexes through CREB activation in cardiac fibroblasts.

Low‐intensity pulsed ultrasound ameliorates angiotensin II-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway

Objective:Cardiac hypertrophy and fibrosis are major pathological manifestations observed in left ventricular remodeling induced by angiotensin II(AngII).Low-intensity pulsed ultrasound(LIPUS)has been reported to ameliorate cardiac dysfunction and myocardial fibrosis in myocardial infarction(MI)through mechano-transduction and its downstream pathways.In this study,we aimed to investigate whether LIPUS could exert a protective effect by ameliorating AngII-induced cardiac hypertrophy and fibrosis and if so,to further elucidate the underlying molecular mechanisms.Methods:We used AngII to mimic animal and cell culture models of cardiac hypertrophy and fibrosis.LIPUS irradiation was applied in vivo for 20 min every 2 d from one week before mini-pump implantation to four weeks after mini-pump implantation,and in vitro for 20 min on each of two occasions 6 h apart.Cardiac hypertrophy and fibrosis levels were then evaluated by echocardiographic,histopathological,and molecular biological methods.Results:Our results showed that LIPUS could ameliorate left ventricular remodeling in vivo and cardiac fibrosis in vitro by reducing AngII-induced release of inflammatory cytokines,but the protective effects on cardiac hypertrophy were limited in vitro.Given that LIPUS increased the expression of caveolin-1 in response to mechanical stimulation,we inhibited caveolin-1 activity with pyrazolopyrimidine 2(pp2)in vivo and in vitro.LIPUS-induced downregulation of inflammation was reversed and the anti-fibrotic effects of LIPUS were absent.Conclusions:These results indicated that LIPUS could ameliorate AngII-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway,providing new insights for the development of novel therapeutic apparatus in clinical practice.

Discovery of novel 4-phenylquinazoline-based BRD4 inhibitors for cardiac fibrosis

Bromodomain containing protein 4(BRD4), as an epigenetic reader, can specifically bind to the acetyl lysine residues of histones and has emerged as an attractive therapeutic target for various diseases,including cancer, cardiac remodeling and heart failure. Herein, we described the discovery of hit 5 bearing4-phenylquinazoline skeleton through a high-throughput virtual screen using 2,003,400 compound library(enamine). Then, structure-activity relationship(SAR) study was performed and 47 new 4-phenylquinazoline derivatives toward BRD4 were further designed, synthesized and evaluated, using HTRF assay set up in our lab. Eventually, we identified compound C-34, which possessed better pharmacokinetic and physicochemical properties as well as lower cytotoxicity against NRCF and NRCM cells, compared to the positive control JQ1. Using computer-based molecular docking and cellular thermal shift assay, we further verified that C-34 could target BRD4 at molecular and cellular levels. Furthermore, treatment with C-34 effectively alleviated fibroblast activation in vitro and cardiac fibrosis in vivo, which was correlated with the decreased expression of BRD4 downstream target c-MYC as well as the depressed TGF-β1/Smad2/3 signaling pathway.Taken together, our findings indicate that novel BRD4 inhibitor C-34 tethering a 4-phenylquinazoline scaffold can serve as a lead compound for further development to treat fibrotic cardiovascular disease.

Harnessing stem cell and lineage reprogramming technology to treat cardiac fibrosis

Cardiac fibrosis is a pathological response characterized by excessive deposition of fibrous connective tissue within the heart.It typically occurs following cardiac injuries or diseases.However,the lack of suitable models for disease modeling and high-throughput drug discovery has hindered the establishment of an effective treatments for cardiac fibrosis.The emergence and rapid progress of stem-cell and lineage reprogramming technology offer an unprecedented opportunity to develop an improved humanized and patient-specific model for studying cardiac fibrosis,providing a platform for screening potential drugs and synchronously elucidating the underlying molecular mechanisms.Furthermore,reprogramming cardiac fibroblasts into cardiomyocyte-like cells to reduce scar volume and induce myocardial tissue regeneration is a promising approach in treating cardiac fibrosis.In this review,we summarize the current advancements in stem cell technologies applied to study cardiac fibrosis and provide insights for future investigations into its mechanisms,drug discovery as well as therapy method.

Cytokine receptor-like factor 1(CRLF1)promotes cardiac fibrosis via ERK1/2 signaling pathway

Cardiac fibrosis is a cause of morbidity and mortality in people with heart disease.Anti-fibrosis treatment is a significant therapy for heart disease,but there is still no thorough understanding of fibrotic mechanisms.This study was carried out to ascertain the functions of cytokine receptor-like factor 1(CRLF1)in cardiac fibrosis and clarify its regulatory mechanisms.We found that CRLF1 was expressed predominantly in cardiac fibroblasts.Its expression was up-regulated not only in a mouse heart fibrotic model induced by myocardial infarction,but also in mouse and human cardiac fibroblasts provoked by transforming growth factor-β1(TGF-β1).Gain-and loss-of-function experiments of CRLF1 were carried out in neonatal mice cardiac fibroblasts(NMCFs)with or without TGF-β1 stimulation.CRLF1 overexpression increased cell viability,collagen production,cell proliferation capacity,and myofibroblast transformation of NMCFs with or without TGF-β1 stimulation,while silencing of CRLF1 had the opposite effects.An inhibitor of the extracellular signal-regulated kinase 1/2(ERK1/2)signaling pathway and different inhibitors of TGF-β1 signaling cascades,comprising mothers against decapentaplegic homolog(SMAD)-dependent and SMAD-independent pathways,were applied to investigate the mechanisms involved.CRLF1 exerted its functions by activating the ERK1/2 signaling pathway.Furthermore,the SMAD-dependent pathway,not the SMAD-independent pathway,was responsible for CRLF1 up-regulation in NMCFs treated with TGF-β1.In summary,activation of the TGF-β1/SMAD signaling pathway in cardiac fibrosis increased CRLF1 expression.CRLF1 then aggravated cardiac fibrosis by activating the ERK1/2 signaling pathway.CRLF1 could become a novel potential target for intervention and remedy of cardiac fibrosis.

Cardiac fibrosis: Histological features, molecular pathways and therapeutic targets

Cardiac fibrosis is defined as the unbalanced production and degradation of cardiac interstitial extracellular matrix(ECM),leading to systolic and diastolic dysfunction,arrhythmias,and adverse outcomes of many cardiac pathophysiological conditions.The accumulation of myocardial ECM increases the risk of arrhythmias and impairs cardiac function,ultimately leading to the development of heart failure.Although slowing or reversing the development of excessive accumulation of ECM and cardiac fibrosis is important for maintaining cardiac function,there is currently no approved treatment for them.Activated cardiac fibroblasts are the main effector cells of cardiac fibrosis.Their expansion after pathophysiologic stimuli such as pressure overload,volume overload,metabolic dysfunction,wound healing,and aging is primarily driven by activating resident interstitial populations.While cardiac fibroblasts are the primary effector cells in the fibrotic heart,monocytes/macrophages,lymphocytes,mast cells,vascular cells,and cardiomyocytes may also contribute to the fibrotic response,by secreting critical fibrotic factors and matricellular proteins.This review discusses histological features,molecular pathways involved in the pathogenesis of cardiac fibrosis and possible therapeutic targets.Understanding the occurrence,development and diffusion mechanisms of cardiac fibrosis has important clinical implications for the discovery of drugs to prevent the progression of cardiac fibrosis.

Long non-coding RNAs in cardiac fibrosis:Regulation of cardiac fibroblasts

Background Cardiac fibrosis,characterized by excessive extracellular matrix(ECM)deposition and increased cardiac fibroblasts(CFs)activity,is a common pathology of various cardiovascular diseases.Cardiac fibrosis decreases ventricular compliance,increases diastolic filling pressure,decreases cardiac oxygen supply,and ultimately impairs the cardiac output.CFs are the main effecter cell type in regulating ECM and predominantly drive the fibrosis process.Despite the critical importance of CFs,our limited understanding of CFs impedes the development of potential therapies that effectively target this cell type and its pathological contribution to disease progression.Recently,long non-coding RNAs(lncRNAs)are emerging as important pathological and physiological regulators of cardiac fibrosis,shedding light on novel molecular mechanisms and potential therapeutic targets.This review discussed the current knowledge regarding the lnc RNAs involved in cardiac fibrosis and summarized their possible molecular mechanisms with special focus on the regulation of CFs.

Molecular mechanisms of AGE/RAGE-mediated fibrosis in the diabetic heart

Chronic hyperglycemia is one of the main characteristics of diabetes. Persistent exposure to elevated glucose levels has been recognized as one of the major causal factors of diabetic complications. In pathologies, like type 2 diabetes mellitus(T2DM), mechanical and biochemical stimuli activate profibrotic signaling cascades resulting in myocardial fibrosis and subsequent impaired cardiac performance due to ventricular stiffness. High levels of glucose nonenzymatically react with long-lived proteins, such as collagen, to form advanced glycation end products(AGEs). AGE-modified collagen increase matrix stiffness making it resistant to hydrolytic turnover, resulting in an accumulation of extracellular matrix(ECM) proteins. AGEs account for many of the diabetic cardiovascular complications through their engagement of the receptor for AGE(RAGE). AGE/RAGE activation stimulates the secretion of numerous profibrotic growth factors, promotes increased collagen deposition leading to tissue fibrosis, as well as increased RAGE expression. To date, the AGE/RAGE cascade is not fully understood. In this review, we willdiscuss one of the major fibrotic signaling pathways, the AGE/RAGE signaling cascade, as well as propose an alternate pathway via Rap1 a that may offer insight into cardiovascular ECM remodeling in T2 DM. In a series of studies, we demonstrate a role for Rap1 a in the regulation of fibrosis and myofibroblast differentiation in isolated diabetic and non-diabetic fibroblasts. While these studies are still in a preliminary stage, inhibiting Rap1 a protein expression appears to down-regulate the molecular switch used to activate the ζ isotype of protein kinase C thereby promote AGE/RAGE-mediated fibrosis.

Canagliflozin attenuates hypertension induced myocardial hypertrophy and fibrosis via RAS and TGF-β1/Smad pathway

Objective:To investigate the effects of cagliazin,a sodium-glucose cotransporter 2 inhibitor(SGLT-2I),on ventricular remodeling in spontaneously hypertensive rats(SHR)through renin angiotensin system(RAS)and transforming growth factor-β1(TGF-β1).Methods:The experiment was divided into 4 groups:normal blood pressure control group,SHR group,cagliet net low-dose group(30mg/kg),cagliet net high-dose group(60mg/kg),once a day for 8 weeks.Normal blood pressure rats(WKY)were used as the control group to measure blood pressure with tail sleeve sphygmomanometer(BP)and blood glucose level was measured with glucose meter Cardiac function was evaluated by echocardiography,cell area of left ventricle was evaluated by histomorphology,real-time quantitative polymerase chain reaction and protein imprinting hybridization were used to detect TGF-β1 Smad4 renin from type I collagen(Col1a)type III collagen(Col3a)matrix metalloproteinase 2(MMP-2)Expression results of angiotensin II1 type receptor 1(AGTR1)and Angiotensin II2 type receptor 2(AGTR2).Results:After 8 weeks of administration,the cardiac weight/body weight ratio(HW/BW)of left ventricular weight/heart weight ratio(LVW/HW)of kaglinet low-dose group and high-dose group was statistically significant compared with that of spontaneous hypertensive rats(P&lt);Compared with SHRs,the expression of Col1a,Col3a,MMP2,TGF-β1,Smad4,Renin AGTR1 was significantly down-regulated and the expression of AGTR2 was up-regulated in cagliet net low-dose and high-dose groups Conclusions:Cagliazin can improve hypertension-induced cardiac remodeling by regulating RAS and TGF-β1/Smad signaling pathways.Conclusion:From the results,canaglifozin was found to ameliorate pressure overload-induced cardiac remodeling by regulating the RAS and TGF-β1/Smad signaling pathway.