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Cardiac fibrosis is a common pathological feature of cardiac remodelling process with disordered expression of multiple genes and eventually lead to heart failure. Emerging evidence suggests that long noncoding RNAs (lncRNAs) have emerged as critical regulators of various biological processes. However, the exact mechanisms of lncRNAs as mediators in cardiac fibrosis have not been fully elucidated. This study aimed to profile the lncRNA expression pattern in human cardiac fibroblasts (HCFs) with cardiac fibrosis. We treated HCFs with transforming growth factor-β (TGF-β) to induce their activation. Then, strand-specific RNA-seq was performed to profile and classify lncRNAs; and perform functional analysis in HCFs. We study the transformation of HCFs with molecular and cell biology methods. Among all identified lncRNA candidates, 176 and 526 lncRNAs were upregulated and downregulated respectively in TGF-β-stimulated HCFs compared with controls. Functional analyses revealed that the target genes of differentially expressed lncRNAs were mainly related to focal adhesion, metabolic pathways, Hippo signaling pathway, PI3K-Akt signaling pathway, regulation of actin cytoskeleton, and hypertrophic cardiomyopathy. As a representative, novel lncRNAs NONHSAG005537 and NONHSAG017620 inhibited the proliferation, migration, invasion, and transformation of HCFs induced by TGF-β. Collectively, our study established the expression signature of lncRNAs in cardiac fibrosis and demonstrated the cardioprotective role of NONHSAG005537 and NONHSAG017620 in cardiac fibrosis, providing a promising target for anti-fibrotic therapy. • We investigated the lncRNA expression profile in cardiac fibrosis with human cardiac fibroblasts. • Strand-specific RNA sequencing was employed to study lncRNAs expression profile. • We confirmed that lncRNAs participated in cardiac fibrosis by bioinformatics analyses. • NONHSAG005537 and NONHSAG017620 attenuates the transformation of human cardiac fibroblasts. • These findings may provide an anti-fibrotic therapy target in cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Non-cardiomyocytes (nonCMs) play an important part in cardiac fibrosis pathophysiology, but the underlying molecular pathways are unknown. Semaglutide has cardioprotective properties, but it is still unclear whether it helps with cardiac fibrosis and what the processes are. The goal of this study is to use single cell transcriptomics approaches to investigate the molecular mechanism of semaglutide's cardioprotective action in obese mice. We found 15 non-CMs, with fibroblasts making up the majority of them. We found eight DEGs that altered significantly following semaglutide treatment by screening for differentially expressed genes (DEGs). DEGs were shown to have biological activities primarily related to extracellular matrix and collagen synthesis and distribution, with Serpinh1 and Pcolce expression being the most dramatically altered. Serpinh1 and Pcolce were mostly found in fibroblasts, which play a key role in the fibrosis of the heart. Furthermore, we discovered that semaglutide lowered cardiac collagen content and alleviated obesity-induced ventricular wall hypertrophy. As a result, our findings show that Serpinh1 and Pcolce, which are expressed by fibroblasts, may play a role in the development of obese cardiac fibrosis. By reducing Serpinh1 and Pcolce expression and delaying cardiac fibrosis, semaglutide may have a cardioprotective effect. • Obesity can significantly increase cardiac collagen content and ventricular wall thickness. • Semaglutide affects the expression of several genes in non-cardiomyocytes of obese mice. • Obesity is involved in cardiac fibrosis by affecting the expression of Serpinh1 and Pcolce in cardiac fibroblasts. • Semaglutide alleviates cardiac fibrosis by inhibiting the expression of fibroblasts Serpinh1 and Pcolce. [ABSTRACT FROM AUTHOR]

Fibrosis has been widely investigated in acute phase of myocardial infarction (MI). However, the mechanism of sustained fibrosis after MI hasn't been elucidated, which eventually gives rise to ventricular aneurysm (VA) formation chronic while lethal. Neutrophil as vital cell facilitating the fibrotic repair after acute MI may not project its effect to chronic phase unless neutrophil extracellular traps (NETs) were secreted and accumulating. The aim of this study was to investigate whether NETs contribute to the sustained fibrosis and VA formation after MI. We identified NETs in ventricular aneurysm of patients. Accordingly, NETs increased in peripheral blood of VA patients. Moreover, in rat VA NETs were also identified. Stimulated by NETs, the migration of fibroblast was enhanced and the differentiation of cardiac myofibroblast was initiated. Smad, MAPK and RhoA signaling pathways were activated by NETs incubation. And additional deposition with DNase I to disrupt NETs and abrogated NETs induced fibrosis both in vivo and vitro. These results collectively demonstrate a novel profibrotic role for NETs in chronic cardiac fibrosis and VA formation. • Identifying that NETs participate in the fibrosis after MI and lead to the formation of ventricular aneurysm. • Identifying that Ventricular aneurysm formed after MI follows the pattern of perivascular fibrosis expansion where NETs exist and crosslinked with thrombosis. • Describing that NETs could induce the differentiation from cardiac fibroblast to myofibroblast and upregulate collagen synthesis. • Employing Dnase I administration as disrupt the DNA skeleton of NETs to abrogate NETs induced fibrotic upregulation both in vivo and vitro. • Providing an accessible and replicable method for neutrophils isolation and NETs acquirement from rats. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis will increase wall stiffness and diastolic dysfunction, which will eventually lead to heart failure. Asenapine maleate (AM) is widely used in the treatment of schizophrenia. In the current study, we explored the potential mechanism underlying the role of AM in angiotensin II (Ang II)-induced cardiac fibrosis. Cardiac fibroblasts (CFs) were stimulated using Ang II with or without AM. Cell proliferation was measured using the cell counting kit-8 assay and the Cell-Light EdU Apollo567 In Vitro Kit. The expression levels of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were detected using immunofluorescence or western blotting. At the protein level, the expression levels of the components of the transforming growth factor beta 1 (TGFβ1)/mitogen-activated protein kinase (MAPK) signaling pathway were also detected. After Ang II stimulation, TGFβ1, TGFβ1 receptor, α-SMA, fibronectin (Fn), collagen type I (Col1), and collagen type III (Col3) mRNA levels increased; the TGFβ1/MAPK signaling pathway was activated in CFs. After AM pretreatment, cell proliferation was inhibited, the numbers of PCNA -positive cells and the levels of cardiac fibrosis markers decreased. The activity of the TGFβ1/MAPK signaling pathway was also inhibited. Therefore, AM can inhibit cardiac fibrosis by blocking the Ang II-induced activation through TGFβ1/MAPK signaling pathway. This is the first report to demonstrate that AM can inhibit Ang II-induced cardiac fibrosis by down-regulating the TGFβ1/MAPK signaling pathway. In this process, AM inhibited the proliferation and activation of CFs and reduced the levels of cardiac fibrosis markers. Thus, AM represents a potential treatment strategy for cardiac fibrosis. • Asenapine maleate (AM): new cardiac uses for an old drug. • AM, as a drug for the treatment of schizophrenia, could inhibit cardiac fibrosis. • AM acts through ROS/TGFβ1/MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

Fibrotic scarring is tightly linked to the development of heart failure in patients with post-myocardial infarction (MI). Atypical chemokine receptor 4 (ACKR4) can eliminate chemokines, such as C–C chemokine ligand 21 (CCL21), which is independently associated with heart failure mortality. However, the role of ACKR4 in the heart during MI is unrevealed. This study aimed to determine whether ACKR4 modulates cardiac remodeling following MI and to illuminate the potential molecular mechanisms. The expression of ACKR4 was upregulated in the border/infarct area, and ACKR4 was predominantly expressed in cardiac fibroblasts (CFs). Knockout of ACKR4 protected against adverse ventricular remodeling in mice post-MI. These protective effects of ACKR4 deficiency were independent of dendritic cell immune response but could be attributed to downregulated CF-derived IL-6, affecting CF proliferation and endothelial cell (EC) functions, which consequently inhibited cardiac fibrosis. ACKR4 promoted IL-6 generation and proliferation of CFs. Besides, ACKR4 induced endothelial-to-mesenchymal transition (EndMT) in ECs through IL-6 paracrine effect. The p38 MAPK/NF-κB signaling pathway was involved in ACKR4 facilitated IL-6 generation. Moreover, ACKR4 overexpression in vivo via AAV9 carrying a periostin promoter aggravated heart functional impairment post-MI, which was abolished by IL-6 neutralizing antibody. Therefore, our study established a novel link between ACKR4 and IL-6 post-MI, indicating that ACKR4 may be a novel therapeutic target to ameliorate cardiac remodeling. • ACKR4 expression is upregulated in infarcted heart and exclusively detected in CFs. • ACKR4 deletion alleviates cardiac remodeling after MI. • The cardioprotective effect induced by ACKR4 deletion is DCs-trafficking independent. • Knockout of ACKR4 reduces proliferation, IL-6 generation of CFs in vitro. • Overexpression of ACKR4 aggravates cardiac dysfunction after MI via IL-6 in vivo. [ABSTRACT FROM AUTHOR]

Sympathetic stimulated-cardiac fibrosis imposes great significance on both disease progression and survival in the pathogenesis of many cardiovascular diseases. However, there are few effective therapies targeting it clinically. The cardioprotective effect of aldehyde dehydrogenase 2 (ALDH2) has been explored in many pathological conditions, whether it can exert benefit effects on chronic sympathetic stimulus-induced cardiac fibrosis remains unclear. In this study, we determined to explore the role of ALDH2 on isoproterenol (ISO)-induced cardiac fibroblasts (CF) proliferation and cardiac fibrosis. It was found that ALDH2 enzymatic activity was impaired in ISO-induced HCF proliferation and Aldh2 deficiency promoted mouse CF proliferation. Alda-1, an ALDH2 activator, exerted obvious suppressive effect on ISO-induced HCF proliferation, together with the induction of cell cycle arrest at G 0 /G 1 phase and decreased expression of cyclin E1 and cyclin-dependent kinase 2 (CDK2). Mechanistically, the inhibitory role of Alda-1 on HCF proliferation was achieved by decreasing mitochondrial reactive oxygen species (ROS) production, which was partially reversed by rotenone, an inducer of ROS. In addition, wild-type mice treated with Alda-1 manifested with reduced fibrosis and better cardiac function after ISO pump. In summary, Alda-1 alleviates sympathetic excitation-induced cardiac fibrosis via decreasing mitochondrial ROS accumulation, highlighting ALDH2 activity as a promising drug target of cardiac fibrosis. • ALDH2 enzymatic activity was impaired in ISO-induced cardiac fibrosis. • ALDH2 activator Alda-1 exerted suppressive effect on ISO-induced HCF proliferation. • Alda-1 inhibited ISO-induced HCF proliferation by reducing mitochondrial ROS level. [ABSTRACT FROM AUTHOR]

Myocardial fibrosis is the pathological consequence of injury-induced fibroblastto-myofibroblast transition, resulting in increased stiffness and diminished cardiac function. Histone modification has been shown to play an important role in the pathogenesis of cardiac fibrosis. Here, we identified H3K27me3 demethylase JMJD3/KDM6B promotes cardiac fibrosis via regulation of fibrogenic pathways. Using neonatal rat cardiac fibroblasts (NRCF), we show that the expression of endogenous JMJD3 is induced by angiotensin II (Ang II), while the principle extracellular matrix (ECM) such as fibronectin, CTGF, collagen I and III are increased. We find that JMJD3 inhibition markedly enhances the suppressive mark (H3K27me3) at the beta (β)-catenin promoter in activated cardiac fibroblasts, and then substantially decreases expression of fibrogenic gene. Both inhibition of β-catenin-mediated transcription with ICG-001 and genetic loss of β-catenin can prevent Ang II-induced ECM deposition. Most importantly, in vivo inhibition of JMJD3 rescues myocardial ischemia-induced cardiac fibrosis and cardiac dysfunction. Collectively, our findings are the first to report a novel role of histone demethylase JMJD3 in the pro-fibrotic cardiac fibroblast phenotype, pharmacological targeting of JMJD3 might represent a promising therapeutic approach for the treatment of human cardiac fibrosis and other fibrotic diseases. Image 1 • JMJD3 expression is induced in activated CFs and fibrotic mouse hearts. • Intervention of JMJD3 significantly alleviates the level of the pro-fibrotic cytokines in activated CFs. • In vivo inhibition of JMJD3 rescues myocardial ischemia-induced cardiac fibrosis and cardiac dysfunction. • JMJD3 inhibition markedly enhances the suppressive mark (H3K27me3) at the β-catenin promoter in activated CFs. [ABSTRACT FROM AUTHOR]

Cardiac fibroblast (CF) differentiation plays a crucial role in cardiac fibrosis, which is a specific manifestation distinguishing pathological cardiac hypertrophy from physiological hypertrophy. The DNA-binding activity of paired box 6 (Pax6) has been shown to be oppositely regulated in physiological and pathological hypertrophy; however, it remains unclear whether Pax6 is involved in CF differentiation during cardiac fibrosis. We found that Pax6 is expressed in the heart of and CFs isolated from adult mice. Moreover, angiotensin II (Ang II) induced the downregulation of Pax6 mRNA and protein expression in fibrotic heart tissue and cardiac myofibroblasts. Pax6 knockdown in CFs promoted the expression of the myofibroblast marker α-smooth muscle actin (α-SMA) and the synthesis of the extracellular matrix (ECM) proteins collagen I and fibronectin. Furthermore, we validated the ability of Pax6 to bind to the promoter regions of Cxcl10 and Il 1 r2 and the intronic region of Tgfb1. Pax6 knockdown in CFs decreased CXC chemokine 10 (CXCL10) and interleukin-1 receptor 2 (IL-1R2) expression and increased transforming growth factor β1 (TGFβ1) expression, mimicking the effects of Ang II. In conclusion, Pax6 exerts an inhibitory effect on CF differentiation and ECM synthesis by transcriptionally activating the expression of the anti-fibrotic factors CXCL10 and IL-1R2 and repressing the expression of the pro-fibrotic factor TGFβ1. Therefore, maintaining Pax6 expression in CFs is essential for preventing CF differentiation, and provides a new therapeutic target for cardiac fibrosis. Image 1 • Ang II decreases Pax6 levels in fibrotic heart tissue and cardiac myofibroblasts. • Pax6 knockdown promotes α-SMA expression and ECM synthesis in CFs. • Pax6 inhibits CF differentiation and ECM synthesis. • Pax6 increases Cxcl10 and Il 1r2 expression but decreases Tgfb1 expression. • Maintaining Pax6 levels can prevent the differentiation of CFs. [ABSTRACT FROM AUTHOR]

Ischaemic heart disease is one of the leading causes of death. Protease-activated receptor 2 (PAR2) is widely expressed within the cardiovascular system and is known to mediate inflammatory processes in various immunocytes, such as macrophages, mastocytes and neutrophils. Here, we investigated whether activating macrophage PAR2 modulates cardiac remodelling in a murine model of myocardial infarction. Myocardial infarction was produced by the permanent ligation of the left anterior descending coronary artery (LAD) in C57BL/6J background wild-type (WT) mice transplanted with bone marrow from WT or PAR2 knockout (PAR2 KO) mice. Hematopoietic deficiency of PAR2 had improvement of left ventricular systolic dysfunction and dilatation and decreased fibrosis deposition in remote zone at 1 week after LAD ligation. Inactivation of PAR2 also led to less recruitment of macrophages in myocardium, which was accompanied by decreased expression of pro-inflammatory cytokines. Furthermore, cultured cardiac fibroblasts (CFs) were activated and showed a fibrotic phenotype after being co-cultured in medium containing PAR2-activating macrophage, which enhances interferon-beta (INF-β) expression. The beneficial effects of macrophages with INF-β neutralisation or PAR2-deletion ameliorates the JAK/STAT3 pathway in CFs, which might be attributed to CF activation. These data suggest that macrophage-derived IFN-β plays a crucial role in adverse cardiac remodelling after myocardial infarction, at least in part, through a PAR2-dependent mechanism. • PAR2 deficiency in macrophage improves cardiac dysfunction in mice after MI. • PAR2 deficiency suppresses macrophage recruitment and inflammatory response in the post-MI hearts. • IFN-β mediates PAR2-related cardiac fibroblast activation through the JAK/STAT3 pathway. [ABSTRACT FROM AUTHOR]

The dysregulation of Long noncoding RNAs (lncRNAs) has been implicated in many cardiovascular diseases, including cardiac fibrosis. However, the functions and mechanisms of lncRNAs in cardiac fibroblasts (CFs) have not been fully elucidated. First, we observed a correlation between cardiac remodeling (CR) and lncRNA FAF (FGF9-associated factor, termed FAF) expression in the heart. In vitro, we found that the expression of lncRNA FAF was altered in CFs, whereas it behaved inconsistently in cardiomyocytes (CMs). Next, we investigated the effects of lncRNA FAF on angiotensinogen II (Ang II)-induced cardiac fibrosis in neonatal rat CFs and explored the mechanism underlying these effects. In this study, lncRNA FAF was enriched in CFs and was associated with cardiac fibrosis. Upregulation of lncRNA FAF significantly restrained Ang II-induced increases in cell proliferation, differentiation and collagen accumulation of CFs. Moreover, we found that the function of lncRNA FAF was mainly realized through Transforming growth factor β1 (TGFβ1) secretion and then downregulated phosphorylation of Smad2/3. Additional analysis revealed that Fibroblast growth factor 9 (FGF9) is a direct target of lncRNA FAF, as the overexpression of lncRNA FAF could increase the expression of FGF9 and knockdown of the FGF9 expression could attenuate the down-regulation of lncRNA FAF on TGFβ1-P-Smad2/3 pathway. Furthermore, knockdown of the FGF9 expression also abolished the inhibitory effect of FAF on fibrosis. In summary, we demonstrated that the overexpression of lncRNA FAF could inhibit fibrosis induced by Ang II via the TGFβ1-P-Smad2/3 signalling by targeting FGF9 in CFs. • LncRNA FAF is Associated with CR and Enriched in CFs. • LncRNA FAF Suppresses Fibrosis Induced by Ang II in CFs. • LncRNA FAF Regulates Fibrosis by Influencing the TGFβ1-P-Smad2/3 Signalling Pathway. • FGF9 Is the Target of LncRNA FAF. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis after myocardial infarction (MI) is mainly associated with cardiac fibroblasts and its differentiation is the key pathological process. However, the cellular mechanism of fibroblast-to-myofibroblast conversion has not been clarified and a deeper mechanistic understanding is needed. We found that miR-574–5p was up-regulated in TGF-β-induced myofibroblast differentiation. Silencing transiently miR-574–5p in HCFs, we found that suppression of miR-574–5p decreased myofibroblasts differentiation as validated by expression levels of fibrosis related genes, EDU imaging assay, wound healing assay and transwell assays. Conversely, overexpression of miR-574–5p displayed opposite results. ARID3A was verified as a direct target gene of miR-574–5p and decreased level of ARID3A forced fibroblast-to-myofibroblast differentiation of TGF-β-induced HCFs. Our data suggests that miR-574–5p plays a pivotal role in human cardiac fibroblasts (HCFs) myofibroblast differentiation and demonstrates that miR-574–5p and arid3a may be a novel therapeutic target for cardiac fibrosis. • We first demonstrated that miR-574–5p promotes the differentiation of HCFs. • ARID3A is the direct target gene of miR-574–5p. • Suppression of ARID3A recovered the anti-fibrotic response of miR-574–5p knockdown on TGF-β stimulation. [ABSTRACT FROM AUTHOR]

Abstract Cardiac fibrosis is an important cardiac remodeling event in the development of inflammation dilated cardiomyopathy （iDCM）. We have previously observed that degradation enhancer of androgen receptor (ASC-J9®) could improve cardiac inflammation and fibrosis. Using Primary CFs, we demonstrated that ASC-J9® attenuates the expression of miR-125b, which subsequently inhibits the generation of collagen. In contrast, overexpressed AR in CFs induced collagen production, increases mir-125b.We also found that inhibition of miR-125b attenuates fibrosis which induced by the overexpression of AR. Our results indentify the functional role for AR as a regulator of cardiac fibrosis due to myocarditis and further show that AR exerts its effect by increasing microRNA-125b expression. Treatment with degradation enhancer of AR limits cardiac fibrosis in iDCM, thereby providing potentially a therapeutic approach for patients with iDCM. Highlights • ASC-J9, a enhancer of AR degradation, attenuation of heart fibrosis in EAM. • Androgen receptor regulates cardiac fibrosis in EAE by increasing microRNA-125b expression. [ABSTRACT FROM AUTHOR]

Glaucocalyxin A (GLA) is a natural ent-Kaurane diterpenoid that possesses cardioprotective effect. Recently, it has been reported that GLA inhibits liver and pulmonary fibrosis, whereas its role in cardiac fibrosis remains unknown. In the present study, we evaluated the effect of GLA on the pathogenesis of cardiac fibrosis in vitro . The results showed that GLA inhibited angiotensin II (Ang II)-induced proliferation and migration in cardiac fibroblasts (CFs). GLA reduced the expression of alpha-smooth muscle actin (α-SMA) in Ang II-induced CFs, suggesting that GLA prevented the differentiation of CFs to myofibroblasts. Furthermore, the production of extracellular matrix (ECM) components including type I collagen (Col-I) and fibronectin, as well as the matrix metalloproteinases (MMPs) including MMP-2 and MMP-9 were reduced by GLA in Ang II-induced CFs. In addition, GLA prevented the Ang II-induced activation of transforming growth factor beta 1 (TGF-β1)/Smad3 pathway in CFs. Collectively, our results demonstrated that GLA acted as an anti-fibrotic agent in cardiac fibrosis, which might be mediated by the regulation of TGF-β1/Smad3 pathway. GLA might be an attractive candidate for improving the prognosis of acute myocardial infarction (AMI) by controlling the cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Uncontrolled cardiac fibrosis following myocardial infarction (MI) is a critical pathological change leading to heart failure. Current pharmacotherapies are limited by unsatisfactory efficacy and undesired systemic side effects. Astaxanthin (ASX) is a natural carotenoid with strong antioxidant and anti-inflammatory activities. The effects of ASX on MI-induced cardiac fibrosis and the underlying mechanisms remain largely unknown. In this study, after the establishment of MI model, mice were administrated with ASX (200 mg/kg⋅d) for 4 weeks. We found that ASX treatment attenuated cardiac fibrosis and improved heart function following MI, as evidenced by reduced collagen I/III ratio, hydroxyproline content and left ventricular end diastolic pressure (LVEDP). Lipidomic analysis revealed the overaccumulation of myocardial ceramides in mice with cardiac fibrosis, which was normalized by ASX treatment. Molecular docking analysis showed that ASX produced a tight fit in the pocket of sphingomyelin phosphodiesterase 1 (SMPD1), a key enzyme in the production of ceramides. Western blot analysis confirmed the significant inhibition of SMPD1 expression by ASX. Furthermore, MI-induced overexpression of transforming growth factor β1 (TGF-β1) and phosphorylated SMAD2/3 were attenuated by ASX administration. SMPD1 knockout (KO) abrogated the beneficial effect of ASX. Taken together, our results suggest that the cardioprotective effects of ASX are mediated by SMPD1 through the indirection inhibition of TGF- β1/SMAD signaling cascade. [ABSTRACT FROM AUTHOR]

Hypertension is a multifactorial chronic inflammatory disease that leads to cardiac remodeling. A-kinase anchor protein 12 (AKAP12) is a scaffolding protein that has multiple functions in various biological events, including the regulation of vessel integrity and differentiation of neural barriers in blood. However, the role of AKAP12 in angiotensin II (Ang II)-induced cardiac injury remains unclear. In the present study, Ang II infusion reduced AKAP12 expressions in the hearts of wild-type (WT) mice, and AKAP12 knockout (KO) enhanced the infiltration of inflammatory cells. In addition, AKAP12 deletion accelerated Ang II-induced cardiac histologic alterations and dysfunction. Further, AKAP12 −/− aggravated heart failure by promoting the inflammation, oxidative stress, cellular apoptosis, and autophagy induced by Ang II. Furthermore, AKAP12 KO elevated Ang II-induced cardiac fibrosis, as indicated by the following: (1) Masson trichrome staining showed that Ang II infusion markedly increased fibrotic areas of the WT mouse heart, which was greatly accelerated in AKAP12 −/− mice; (2) immunohistochemistry analysis showed increased expression of transforming growth factor β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in the AKAP12 −/− mouse heart; (3) reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) analysis showed increased expression of fibrosis-related molecules in the AKAP12-deficient mouse heart; and (4) Western blot analysis indicated significantly higher upregulation of p-SMAD2/3 in the AKAP12 −/− mouse heart. In vitro, AKAP12 knockdown in HL-1 cells was responsible for TGF-β1-induced inflammation, the generation of reactive oxygen species (ROS), apoptosis, autophagy, and fibrosis. Furthermore, overexpression of AKAP12 reduced fibrosis triggered by TGF-β1 in cells. Overall, our study suggests that fibrosis induced by Ang II may be alleviated by AKAP12 expression through inactivation of the TGF-β1 pathway. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is one of the primary mechanisms of ventricular remodeling, and there is no effective method for reversal. Activation of calcium sensing receptor (CaSR) has been reported to be involved in the development of myocardial fibrosis, but the molecular mechanism for CaSR activation has not yet been clarified and needs to be further explored. Here, we found that AngII induces cardiac fibroblast proliferation and phenotypic transformation in a dose-dependent manner with increased CaSR and autophagy related protein (Beclin1, LC3B) expression. CaSR activation results in intracellular calcium release, MEK1/2 pathway phosphorylation, autophagy activation and collagen formation induced by AngII in cardiac fibroblasts. However, pretreating the cells with Calhex 231 , PD98059 or 3-MA partially blocked AngII-induced cardiac fibrosis. Our data indicate that the activation of CaSR-mediated MEK/ERK and autophagic pathways is involved in AngII-induced cardiac fibrosis in vitro. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is a pathological feature common to a variety of heart diseases such as myocardial infarction, arrhythmias, cardiomyopathies and heart failure. Emerging data has indicted that autophagy is involved in fibrotic synthesis. Relaxin as a pleiotropic hormone can attenuate cardiac fibrosis and hypertrophy, however the exact molecular mechanism remains largely unknown. In this work, we evaluated whether the antifibrotic effect of relaxin relies on regulating autophagy in primary cardiac fibroblasts (CFs). Our results showed that relaxin significantly attenuated TGFβ1-induced autophagy in parallel with the reduction of fibrosis. Moreover, relaxin inhibited the phosphorylation of Stat3/Smad3 signaling. Then we observed that knockdown of Stat3 synchronously suppressed the fibrogenesis and autophagic flux which was stimulated by TGFβ1 in CFs. More importantly, we simultaneously administrated relaxin and Stat3 knockdown into CFs, which did not cause further downregulation of autophagy process and collagen protein compared with only Stat3 knockdown or relaxin treatment. These data suggested that relaxin ameliorates TGFβ-induced fibrosis dependent on Stat3 signaling-mediated autophagy. This study uncovered a previously unrecognized antifibrotic role of relaxin in cardiac fibrosis, which is achieved through the inhibition of Stat3-dependent autophagy, implying a potential therapeutic target in fibrotic diseases. [ABSTRACT FROM AUTHOR]

The immunoproteasome is a multicatalytic protease complex in all eukaryotic cells, which plays a key role in regulating essential cellular processes. However, the role of immunoproteasome subunit β2i in regulation of cardiac fibrosis and inflammation in deoxycorticosterone-acetate (DOCA)/salt mice remains unknown. Wild-type (WT) and β2i knockout (KO) mice were subjected to uninephrectomy and DOCA/salt treatment for 21 days. Blood pressure was measured by the tail-cuff system. Cardiac function and remodeling were examined by echocardiography, hematoxylin-eosin (H&E) and Masson's trichrome staining. The gene and protein expressions were detected by quantitative real-time PCR, and Western blot analysis. After 21 days, DOCA/salt treatment significantly up-regulated the expression of β2i mRNA and protein in the hearts. Moreover, systolic blood pressure and heart weight/body weight (HW/BW) ratio were significantly higher in DOCA/salt mice than in sham groups, and these effects were markedly reversed in β2i knockout mice. Importantly, DOCA/salt-induced cardiac fibrosis, inflammation and the expression of collagen I, collagen III, α-SMA, IL-1β, IL-6 and TNF-α in the wild-type hearts, which were markedly attenuated by β2i knockout. These beneficial effects were due, at least in part, to the inhibition of IκBα/NF-κB and TGF-β1/Smad2/3 signaling pathways. Collectively, these findings indicate that knockout of β2i ameliorates DOCA/salt-induced cardiac fibrosis and inflammation, and may be a novel potential therapeutic target for hypertensive heart diseases. [ABSTRACT FROM AUTHOR]

With aging and stress, the myocardium undergoes structural remodeling, often leading to fibrosis. The purpose of this study is to examine whether lumican, one of the class II small leucine-rich proteoglycans, has a protective role in cardiac remodeling and fibrosis. In attempts to elucidate the hypothesis that lumican may have a protective role in cardiac remodeling and fibrosis, we compared the cardiac phenotypes of young (3-month-old) and elder (6-month- and 12-month-old) lumican -null ( Lum −/− ) mice. Extra-cellular matrix remodeling and apoptosis are examined to determine the roles of lumican on age-dependent cardiac fibrosis induced by isoproterenol. Compared to wild type littermates, Lum −/− mice exhibited higher mortality due to significantly impaired systolic function, which was associated with an increase of atrial natriuretic peptide (ANP) secreted by the ventricles in response to excessive stretching of myocytes. Masson's Trichrome and silver stains showed significantly more severe ventricle fibrosis in Lum −/− mice. Interestingly, rate of cell death mediated via apoptosis illustrated by the expression of caspase 3 and TUNEL assay was lower in Lum −/− mice after isoproterenol infusion. In addition, Lum −/− mice exhibited higher levels of TGF-β, collagen I/III, and membrane-type matrix metalloproteinase-1 (MT1-MMP/MMP-14) during cardiac remodeling. This study shows that alternations of lumican might be implicated in the pathogenesis of cardiac fibrosis and suggests lumican as novel targets for cardiac fibrosis therapy. Further studies are required to define the mechanism by which lumican modulates cardiac remodeling. [ABSTRACT FROM AUTHOR]

Lysyl oxidase (LOX) catalyzes crosslink formation between fibrillar collagens and elastins and an increase in LOX activity has been associated with cardiac fibrosis following myocardial infarction (MI). It has been previously reported that LOX expression is regulated by growth factors and cytokines including transforming growth factor (TGF-β1); however, it is unclear how the biophysical and biochemical properties of the cellular microenvironment affect LOX expression. In this study, we isolated rat cardiac fibroblasts (CF) and infarct cardiac fibroblasts (ICF), from healthy and 1-week post-MI left ventricular tissue respectively, and cultured them under varied substrate conditions in vitro to assess their influence on LOX expression. Culture of ICF on collagen I-coated plates increased LOX expression versus uncoated plates with an additional increase observed with the presence of TGF-β1. To further investigate the effect of integrin interactions with collagen I on LOX expression, we inhibited the α2β1 integrin from binding to collagen I and found gene and protein expression of LOX to be downregulated. Together, this demonstrates that the interaction of α2β1 integrin to collagen I in the cellular microenvironment can regulate expression of LOX. Further studies investigating additional integrin interactions may identify therapeutic targets for treating cardiac fibrosis. [ABSTRACT FROM AUTHOR]