MicroRNA-99b-3p promotes angiotensin II-induced cardiac fibrosis in mice by targeting GSK-3β

Research Progress of miRNA in Heart Failure: Prediction and Treatment

ABSTRACT

This review summarizes the multiple roles of microRNAs (miRNAs) in the prediction and treatment of heart failure (HF), including the molecular mechanisms regulating cell apoptosis, myocardial fibrosis, cardiac hypertrophy, and ventricular remodeling, and highlights the importance of miRNAs in the prognosis of HF. In addition, the strategies for alleviating HF with miRNA intervention are discussed. On the basis of the challenges and emerging directions in the research and clinical practice of HF miRNAs, it is proposed that miRNA-based therapy could be a new approach for prevention and treatment of HF.

Inhibition of miR-146b-5p alleviates isoprenaline-induced cardiac hypertrophy via regulating DFCP1

Pathological cardiac hypertrophy often precedes heart failure due to various stimuli, yet effective clinical interventions remain limited. Recently, microRNAs (miRNAs) have been identified as critical regulators of cardiovascular development. In this study, we investigated the role of miR-146b-5p and its underlying mechanisms of action in cardiac hypertrophy. Isoprenaline (ISO) treatment induced significant hypertrophy and markedly enhanced the expression of miR-146b-5p in cultured neonatal rat cardiomyocytes and hearts of C57BL/6 mice. Transfection with the miR-146b-5p mimic led to cardiomyocyte hypertrophy accompanied by autophagy inhibition. Conversely, miR-146b-5p inhibition significantly alleviated ISO-induced autophagy depression, thereby mitigating cardiac hypertrophy both in vitro and in vivo. Our results showed that the autophagy-related mediator double FYVE domain-containing protein 1 (DFCP1) is a target of miR-146b-5p. MiR-146b-5p blocked autophagic flux in cardiomyocytes by suppressing DFCP1, thus contributing to hypertrophy. These findings revealed that miR-146b-5p is a potential regulator of autophagy associated with the onset of cardiac hypertrophy, suggesting a possible therapeutic strategy involving the inhibition of miR-146b-5p.

Caffeic acid mitigates myocardial fibrosis and improves heart function in post-myocardial infarction by inhibiting transforming growth factor-β receptor 1 signaling pathways

Myocardial fibrosis is a pathological, physiological change that results from alterations, such as inflammation and metabolic dysfunction, after myocardial infarction (MI). Excessive fibrosis can cause cardiac dysfunction, ventricular remodeling, and heart failure. Caffeic acid (CA), a natural polyphenolic acid in various foods, has cardioprotective effects. This study aimed to explore whether CA exerts a cardioprotective effect to inhibit myocardial fibrosis post-MI and elucidate the underlying mechanisms. Histological observations indicated that CA ameliorated ventricular remodeling induced by left anterior descending coronary artery ligation in MI mice and partially restored cardiac function. CA selectively targeted transforming growth factor-β receptor 1 (TGFBR1) and inhibited TGFBR1-Smad2/3 signaling, reducing collagen deposition in the infarcted area of MI mice hearts. Furthermore, cell counting (CCK-8) assay, 5-ethynyl-2'-deoxyuridine assay, and western blotting revealed that CA dose-dependently decreased the proliferation, collagen synthesis, and activation of the TGFBR1-Smad2/3 pathway in primary cardiac fibroblasts (CFs) stimulated by TGF-β1 in vitro. Notably, TGFBR1 overexpression in CFs partially counteracted the inhibitory effects of CA. These findings suggest that CA effectively mitigates myocardial fibrosis and enhances cardiac function following MI and that this effect may be associated with the direct targeting of TGFBR1 by CA.

Panax notoginseng saponins improve oral submucous fibrosis by inhibiting the Wnt/β-catenin signal pathway

OBJECTIVE

Oral submucous fibrosis (OSF) is a chronic, insidious, progressive mucosal disease that may be affected by mutations in the Wnt/β-catenin signaling pathway. Panax notoginseng saponins (PNS) is a powerful anti-fibrosis agent; however, its effect and mechanism in treating OSF remain unclear. This study investigated the effect and mechanism of PNS treatment for OSF.

STUDY DESIGN

Arecoline was used to induce OSF models in vivo and in vitro, which were then treated with PNS. Hematoxylin-eosin (HE) and Masson trichrome staining were used to observe histopathology changes; E-cadherin and β-catenin were detected by Immunohistochemical assay, and type Ⅰ collagen (CollA1) and β-catenin were detected by immunofluorescent staining. The Wnt/β-catenin pathway and fibrosis signs were assessed using Western Blot and real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

The expression of CollA1, Wnt1, and β-catenin were increased, and E-cadherin, GSK-3β, and β-catenin expression were decreased in OSF models. PNS and inhibitor intervention increased E-cadherin, Wnt1, and β-catenin and decreased CollA1 and GSK-3β in a dose-dependent manner.

CONCLUSION

PNS can improve OSF by inhibiting the Wnt/β-catenin signal pathway and thus may be used as a potential medicine for the treatment of OSF.

miRNA Expression Profiles in Isolated Ventricular Cardiomyocytes: Insights into Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX), widely used as a chemotherapeutic agent for various cancers, is limited in its clinical utility by its cardiotoxic effects. Despite its widespread use, the precise mechanisms underlying DOX-induced cardiotoxicity at the cellular and molecular levels remain unclear, hindering the development of preventive and early detection strategies. To characterize the cytotoxic effects of DOX on isolated ventricular cardiomyocytes, focusing on the expression of specific microRNAs (miRNAs) and their molecular targets associated with endogenous cardioprotective mechanisms such as the ATP-sensitive potassium channel (KATP), Sirtuin 1 (SIRT1), FOXO1, and GSK3β. We isolated Guinea pig ventricular cardiomyocytes by retrograde perfusion and enzymatic dissociation. We assessed cell morphology, Reactive Oxygen Species (ROS) levels, intracellular calcium, and mitochondrial membrane potential using light microscopy and specific probes. We determined the miRNA expression profile using small RNAseq and validated it using stem-loop qRT-PCR. We quantified mRNA levels of some predicted and validated molecular targets using qRT-PCR and analyzed protein expression using Western blot. Exposure to 10 µM DOX resulted in cardiomyocyte shortening, increased ROS and intracellular calcium levels, mitochondrial membrane potential depolarization, and changes in specific miRNA expression. Additionally, we observed the differential expression of KATP subunits (ABCC9, KCNJ8, and KCNJ11), FOXO1, SIRT1, and GSK3β molecules associated with endogenous cardioprotective mechanisms. Supported by miRNA gene regulatory networks and functional enrichment analysis, these findings suggest that DOX-induced cardiotoxicity disrupts biological processes associated with cardioprotective mechanisms. Further research must clarify their specific molecular changes in DOX-induced cardiac dysfunction and investigate their diagnostic biomarkers and therapeutic potential.

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

MicroRNAs regulating signaling pathways in cardiac fibrosis: potential role of the exercise training

Cardiovascular and metabolic diseases such as hypertension, type 2 diabetes, and obesity develop long-term fibrotic processes in the heart, promoting pathological cardiac remodeling, including after myocardial infarction, reparative fibrotic processes also occur. These processes are regulated by many intracellular signaling pathways that have not yet been completely elucidated, including those associated with microRNA (miRNA) expression. miRNAs are small RNA transcripts (18-25 nucleotides in length) that act as posttranscriptionally regulators of gene expression, inhibiting or degrading one or more target messenger RNAs (mRNAs), and proven to be involved in many biological processes such as cell cycle, differentiation, proliferation, migration, and apoptosis, directly affecting the pathophysiology of several diseases, including cardiac fibrosis. Exercise training can modulate the expression of miRNAs and it is known to be beneficial in various cardiovascular diseases, attenuating cardiac fibrosis processes. However, the signaling pathways modulated by the exercise associated with miRNAs in cardiac fibrosis were not fully understood. Thus, this review aims to analyze the expression of miRNAs that modulate signaling pathways in cardiac fibrosis processes that can be regulated by exercise training.

Nur77 alleviates cardiac fibrosis by upregulating GSK-3β transcription during aging

Cardiac fibrosis is associated with aging, for which no targeted therapies are available. With aging, the levels of nerve growth factor-induced gene B (Nur77) are reduced during cardiac remodelling; however, its role in cardiac fibrosis in aging remains unclear. Here, we found that Nur77 knockout increased cardiac structure abnormalities, systolic and diastolic dysfunction, cardiac hypertrophy, and fibrotic marker expression in 15-month-old mice. Furthermore, Nur77 deficiency induced collagen type I (Col-1) and α-smooth muscle actin overproduction in transforming growth factor beta (TGF-β) treated H9c2 cells, whereas Nur77 overexpression attenuated this effect. Nur77 deficiency in vivo and in vitro downregulated glycogen synthase kinase (GSK)-3β expression and increased β-catenin activity, while its overexpression increased GSK-3β expression. GSK-3β knockdown counteracted the anti-fibrotic effect of Nur77 on TGF-β-treated H9c2 cells. Chromatin immunoprecipitation and luciferase reporter assay results suggested GSK-3β as the direct target of Nur77. Our findings suggest that Nur77 directly initiates GSK-3β transcription and age-related cardiac fibrosis partly through the GSK-3β/β-catenin pathway. This study proposes a novel mechanism for Nur77 regulating cardiac fibrosis and suggests Nur77 as a target for the prevention and treatment of aging-associated cardiac fibrosis and heart failure.

Epigenetic signatures in cardiac fibrosis: Focusing on noncoding RNA regulators as the gatekeepers of cardiac fibroblast identity

Cardiac fibroblasts play a pivotal role in cardiac fibrosis by transformation of fibroblasts into myofibroblasts, which synthesis and secrete a large number of extracellular matrix proteins. Ultimately, this will lead to cardiac wall stiffness and impaired cardiac performance. The epigenetic regulation and fate reprogramming of cardiac fibroblasts has been advanced considerably in recent decades. Non coding RNAs (microRNAs, lncRNAs, circRNAs) regulate the functions and behaviors of cardiac fibroblasts, including proliferation, migration, phenotypic transformation, inflammation, pyroptosis, apoptosis, autophagy, which can provide the basis for novel targeted therapeutic treatments that abrogate activation and inflammation of cardiac fibroblasts, induce different death pathways in cardiac fibroblasts, or make it sensitive to established pathogenic cells targeted cytotoxic agents and biotherapy. This review summarizes our current knowledge in this field of ncRNAs function in epigenetic regulation and fate determination of cardiac fibroblasts as well as the details of signaling pathways contribute to cardiac fibrosis. Moreover, we will comment on the emerging landscape of lncRNAs and circRNAs function in regulating signal transduction pathways, gene translation processes and post-translational regulation of gene expression in cardiac fibroblast. In the end, the prospect of cardiac fibroblasts targeted therapy for cardiac fibrosis based on ncRNAs is discussed.

Exosomes derived from cardiac fibroblasts with angiotensin II stimulation provoke hypertrophy and autophagy inhibition in cardiomyocytes

Although accumulating evidence has revealed that autophagy inhibition contributes to the development of pathological cardiac hypertrophy, the mechanisms leading to declined autophagy activity in the hypertrophic heart remain to be elucidated. Exosomes are known to be important mediators of intercellular communication, and the involvement of exosomes in cardiovascular abnormities has attracted increasing attentions. Cardiac fibroblasts (CFs) are the most abundant cell type in the heart. Here, we investigated the potential role of CFs-derived exosomes in regulating cardiomyocyte hypertrophy and autophagy. Exosomes from rat CFs treated with angiotensin II (Ang II-CFs-exosomes) were collected and characterized. Our experiments showed that these exosomes could induce hypertrophic responses and impair autophagy activity in primary neonatal rat cardiomyocytes (NRCMs). Ang II-CFs-exosomes blocked the autophagic flux of NRCMs via inhibiting the formation of autolysosomes. Moreover, the pro-hypertrophic effects and autophagy inhibition induced by Ang II-CFs-exosomes was validated in mice receiving injection of the exosomes. These findings highlight a novel role of Ang II-CFs-exosomes in suppressing cardiomyocyte autophagy, which may help to better understand the pathogenesis of cardiac hypertrophy.

miRNA-103-3p-Hlf regulates apoptosis and autophagy by targeting hepatic leukaemia factor in heart failure

AIMS

Cardiomyocyte apoptosis is an important factor leading to the occurrence and development of heart failure (HF), which is associated with high mortality of patients with cardiovascular diseases. This study aims to investigate the underlying mechanisms of HF in terms of expression and regulation patterns using bioinformatics and experimental validation.

METHODS AND RESULTS

Two HF datasets were collected: a dataset GSE112056 downloaded from the GEO database (including mRNA and miRNA sequencing data) and another is the laboratory-owned mRNA dataset. Differential mRNAs and miRNAs in the two datasets were screened using the raw Bayesian approach method. Gene Ontology was used to perform functional enrichment analysis of the differential mRNAs and co-expression network analysis of the differential mRNAs, combined with nuclear transcription factors in the differential miRNAs and mRNAs for target gene prediction. A HF cell model was constructed using mouse cardiomyocytes (HL-1), and the role and mechanism of miRNA-103-3p-Hlf (hepatic leukaemia factor) in the process of HF was verified by cell transfection, luciferase reporter gene, WB, and qPCR. We found that Hlf gene expression was decreased in the HF model group and strongly correlated with FYCO1 (FYVE and coiled-coil domain-containing protein 1) gene, a phenomenon enriched in apoptotic autophagy-related pathways. MiR-103-3p expression was up-regulated in the HF model group, and its targeting correlation with Hlf was confirmed by luciferase activity assay. In the HL-1 cell model, miR-103-3p significantly promoted apoptosis and inhibited autophagy in HL-1 cells (all P < 0.05), and overexpression of the Hlf gene reversed this phenomenon, inhibiting apoptosis and promoting autophagy in HL-1 cells (all P < 0.05).

CONCLUSIONS

MiR-103-3p affects myocardial cells apoptosis and autophagy by targeting Hlf, playing as a potential therapeutic biomarker for HF progression.

MicroRNA delivery based on nanoparticles of cardiovascular diseases

Cardiovascular disease, especially myocardial infarction, is a serious threat to human health. Many drugs currently used cannot achieve the desired therapeutic effect due to the lack of selectivity. With the in-depth understanding of the role of microRNA (miRNA) in cardiovascular disease and the wide application of nanotechnology, loading drugs into nanoparticles with the help of nano-delivery system may have a better effect in the treatment of cardiomyopathy. In this review, we highlight the latest research on miRNAs in the treatment of cardiovascular disease in recent years and discuss the possibilities and challenges of using miRNA to treat cardiomyopathy. Secondly, we discuss the delivery of miRNA through different nano-carriers, especially inorganic, polymer and liposome nano-carriers. The preparation of miRNA nano-drugs by encapsulating miRNA in these nano-materials will provide a new treatment option. In addition, the research status of miRNA in the treatment of cardiomyopathy based on nano-carriers is summarized. The use of this delivery tool cannot only realize therapeutic potential, but also greatly improve drug targeting and reduce side effects.

Hastatoside attenuatescarbon tetrachloride-induced liver fibrosis by targeting glycogen synthase kinase-3β

BACKGROUND

Hastatoside is an iridoid glycoside extracted from the herb, Verbena officinalis, that exerts various pharmacological effects, including anti-inflammatory, sleep-promoting, and analgesic effects. However, only a few studies have reported the efficacy of hastatoside in liver fibrosis. Liver fibrosis is a pathophysiological process, and its persistence can seriously affect the quality of life and well-being of the patients.

HYPOTHESIS/PURPOSE

This study aimed to investigate the role of hastatoside on liver fibrosis and its possible underlying mechanisms.

METHODS

C57BL/6 J mice with carbon tetrachloride (CCl₄)-induced hepatic fibrosis were used as the in vivo models. Histological features of the liver were observed using Masson's trichrome and hematoxylin-eosin staining. Alanine aminotransferase and aspartate aminotransferase levels and the hepatic fibrosis indices (type 3 procollagen, laminin, and hyaluronic acid) were measured using corresponding assay kits. LX-2 human hepatic stellate cells (HSCs) stimulated with the transforming growth factor β1 were used as the vitro models. Transfection of the glycogen synthase kinase (GSK)-3β small interfering RNA (siRNA) and β-catenin plasmids was also performed in vitro. Protein levels of GSK-3β, phospho-GSK-3β (Ser 9), α-smooth muscle actin, collagen type I alpha 1, c-Myc, cyclin D1, and β-catenin were determined via western blotting. Moreover, the p-GSK-3β:GSK-3β ratio was calculated to determine the GSK-3β activity.

RESULTS

Hastatoside prevented CCl₄-induced liver injury and histological damage. It inhibited the upregulation of α-SMA and Col1α1 levels in a CCl₄-induced mouse hepatic fibrosis model. In vitro, hastatoside inhibited the proliferation and activation of HSCs by decreasing the expression levels of cyclin D1 and c-Myc and the proportion of LX-2 cells activated in the G0/G1 phase. Molecular docking results showed that hastatoside bound to GSK-3β. Hastatoside significantly increased the GSK-3β activity and inhibited the downstream effector expression of β-catenin.

CONCLUSION

These findings suggest that hastatoside can bind to GSK-3β and promote its activity, while inhibiting the GSK-3β downstream effector expression of β-catenin, thereby inhibiting the activation and proliferation of HSCs, which further prevents the development of liver fibrosis. These results provide innovative insights into the underlying liver fibrosis. Moreover, hastatoside is a potential anti-fibrosis monomer that can potentially be used for the treatment of liver fibrosis.

miR-96-5p regulates myocardial infarction-induced cardiac fibrosis via Smad7/Smad3 pathway

Fibrotic remodelling contributes to heart failure in myocardial infarction. MicroRNAs (miRNAs) play a crucial role in myocardial fibrosis. However, current antifibrotic therapeutic strategies using miRNAs are far from effective. In this study, we aim to investigate the effect of miR-96-5p on cardiac fibrosis. Our work reveals a significant upregulation of miR-96-5p level in the ventricular tissues of myocardial infarction mice, as well as in neonatal rat cardiac fibroblasts stimulated with TGF-β or Ang II as shown by qPCR assay. In myocardial infarction mice, miR-96-5p knockdown using antagomir alleviates the aggravated cardiac fibrosis and exacerbated myocardial function caused by myocardial infarction surgery as shown by the echocardiography and Masson's staining analysis. In contrast, immunofluorescence staining results reveal that miR-96-5p overexpression in neonatal rat cardiac fibroblasts contributes to an increase in the expressions of fibrosis-associated genes and promotes the proliferation and differentiation of cardiac fibroblasts. Conversely, miR-96-5p downregulation using inhibitor presents adverse consequences. Furthermore, Smad7 expression is downregulated in fibrotic cardiac tissues, and the Smad7 gene is identified as a direct target of miR-96-5p by dual luciferase assay. Indeed, Smad7 knockdown weakens the anti-fibrotic effect of the miR-96-5p inhibitor on cardiac fibroblasts. Moreover, Smad3 phosphorylation is elevated in fibrotic cardiac tissues, and interestingly, the Smad3 inhibitor suppresses the profibrotic effect of the miR-96-5p mimic. Taken together, our findings demonstrate that the Smad7/Smad3 signaling pathway mediates the profibrotic effect of miR-96-5p in cardiac fibrosis.

miR-409-3p Regulated by GATA2 Promotes Cardiac Fibrosis through Targeting Gpd1

Cardiac fibrosis is a hallmark of numerous chronic cardiovascular diseases that leads to heart failure. However, there is no validated therapy for it. Dysregulation of microRNAs has been confirmed to be involved in cardiac fibrosis development. However, the regulatory network was not well explored. This study was the first to highlight the role and molecular mechanism of miR-409-3p in cardiac fibrosis. We found that miR-409-3p was consistently increased in three fibrotic models, including heart tissues of postmyocardial infarction (MI) mice and neonatal rat cardiac fibroblasts treated with angiotensin II (Ang II) or transforming growth factor-β (TGF-β). Furthermore, myocardial infarction surgery-induced cardiac fibrosis and dysfunction were attenuated by systemic delivery of miR-409-3p antagomir. Notably, transfection with miR-409-3p mimics promoted the proliferation of cardiac fibroblasts and fibroblast-to-myofibroblast differentiation, accompanied by upregulated expression of Col1a1, Col3a1, and α-SMA. On the contrary, the miR-409-3p inhibitor exhibited the opposite effect. Following this, we verified Gpd1 as a direct target of miR-409-3p. Gpd1 siRNA abolished the antifibrotic effect of miR-409-3p inhibitor in neonatal rat cardiac fibroblasts, suggesting that miR-409-3p promotes cardiac fibrosis at least partially through Gpd1. Moreover, GATA2 was identified as a cardiac fibrosis-associated upstream positive transcription factor of miR-409-3p. Finally, these findings suggest that modulating miR-409-3p could be a potential therapeutic method for cardiac fibrosis.

Epididymal white adipose tissue promotes angiotensin II-induced cardiac fibrosis in an exosome-dependent manner

Cardiac fibrosis is a process characterized by extracellular matrix accumulation leading to myocardial dysfunction. Angiotensin II (Ang II) has been shown to play an important role in the pathogenesis of cardiac fibrosis. However, the underlying mechanisms are not well established. Dysfunction of adipose tissue has been shown to promote remote organ injury, but its role in Ang II-induced cardiac remodeling is still unclear. In this study, we demonstrated that epididymal white adipose tissue (eWAT) promoted Ang II-induced cardiac fibrosis and subsequent cardiac dysfunction in an exosome-dependent manner. Both eWAT removal and administration of an inhibitor of exosome biogenesis strongly attenuated Ang II-induced abnormalities. Moreover, exosomes isolated from Ang II-stimulated adipocytes promoted cardiac fibroblasts (CFs) activity. A mechanistic study identified that the miR-23a-3p level was significantly increased in exosomes derived from Ang II-challenged adipocytes and serum exosomes from Ang II-infused mice. Importantly, tail vein injection of ago-miR-23a-3p caused cardiac fibrosis and dysfunction, while antago-miR-23a-3p inhibited Ang II-induced cardiac fibrosis. Bioinformatics analysis and further validation experiments revealed that RAP1 is a direct downstream target of miR-23a-3p, and overexpression of RAP1 reversed the profibrotic effect of miR-23a-3p. Taken together, these findings elucidated the role of eWAT in Ang II-induced myocardial fibrosis and indicated that adipocyte-derived exosomes mediate pathologic communication between dysfunctional adipose tissue and the heart by transporting miR-23a-3p into CFs, transforming fibroblasts into myofibroblasts and promoting excessive collagen deposition by targeting RAP1. Prevention of abnormal adipocyte exosome production, inhibition of miR-23a-3p biogenesis, and treatment with a miR-23a-3p antagonist are novel strategies for treating cardiac fibrosis.

chi-miR-99b-3p Regulates the Proliferation of Goat Skeletal Muscle Satellite Cells In Vitro by Targeting Caspase-3 and NCOR1

We previously found that chi-miR-99b-3p was highly expressed in the skeletal muscle of 7-month-old (rapid growth period) goats and speculated that it may be associated with muscle development. To further investigate the role of chi-miR-99b-3p in goats, we found that chi-miR-99b-3p acted as a myogenic miRNA in the regulation of skeletal muscle development. Dual-luciferase reporter assays, qRT-PCR, and Western blot results confirmed that Caspase-3 and nuclear receptor corepressor 1 were direct targets for chi-miR-99b-3p as their expression was inhibited by this miR. Cell proliferation and qRT-PCR assays showed that chi-miR-99b-3p promoted proliferation through relevant targets and intrinsic apoptosis-related genes in goat skeletal muscle satellite cells (SMSCs), whereas inhibition of chi-miR-99b-3p had the opposite effect. Furthermore, integrative transcriptomic analysis revealed that overexpression of chi-miR-99b-3p induced various differentially expressed (DE) genes mainly associated with the cell cycle, relaxin signaling pathway, DNA replication, and protein digestion and absorption. Notably, most of the cell-cycle-related genes were downregulated in SMSCs after miR-99b-3p upregulation, including the pro-apoptosis-related gene BCL2. In addition, 47 DE miRNAs (16 upregulated and 31 downregulated) were determined by Small RNA-sequencing in SMSCs after chi-miR-99b-3p overexpression. Based on the KEGG enrichment analysis, we found that these DE miRNAs were involved in the biological pathways associated with the DE genes. Our study demonstrated that chi-miR-99b-3p was an effective facilitator of goat SMSCs and provided new insights into the mechanisms by which miRNAs regulate skeletal muscle growth in goats.

Novel Therapies for the Treatment of Cardiac Fibrosis Following Myocardial Infarction

Cardiac fibrosis is a common pathological consequence of most myocardial diseases. It is associated with the excessive accumulation of extracellular matrix proteins as well as fibroblast differentiation into myofibroblasts in the cardiac interstitium. This structural remodeling often results in myocardial dysfunctions such as arrhythmias and impaired systolic function in patients with heart conditions, ultimately leading to heart failure and death. An understanding of the precise mechanisms of cardiac fibrosis is still limited due to the numerous signaling pathways, cells, and mediators involved in the process. This review article will focus on the pathophysiological processes associated with the development of cardiac fibrosis. In addition, it will summarize the novel strategies for anti-fibrotic therapies such as epigenetic modifications, miRNAs, and CRISPR technologies as well as various medications in cellular and animal models.

Roles of Epigenetics in Cardiac Fibroblast Activation and Fibrosis

Cardiac fibrosis is a common pathophysiologic process associated with numerous cardiovascular diseases, resulting in cardiac dysfunction. Cardiac fibroblasts (CFs) play an important role in the production of the extracellular matrix and are the essential cell type in a quiescent state in a healthy heart. In response to diverse pathologic stress and environmental stress, resident CFs convert to activated fibroblasts, referred to as myofibroblasts, which produce more extracellular matrix, contributing to cardiac fibrosis. Although multiple molecular mechanisms are implicated in CFs activation and cardiac fibrosis, there is increasing evidence that epigenetic regulation plays a key role in this process. Epigenetics is a rapidly growing field in biology, and provides a modulated link between pathological stimuli and gene expression profiles, ultimately leading to corresponding pathological changes. Epigenetic modifications are mainly composed of three main categories: DNA methylation, histone modifications, and non-coding RNAs. This review focuses on recent advances regarding epigenetic regulation in cardiac fibrosis and highlights the effects of epigenetic modifications on CFs activation. Finally, we provide some perspectives and prospects for the study of epigenetic modifications and cardiac fibrosis.

Non-coding RNAs: Important participants in cardiac fibrosis

Cardiac remodeling is a pathophysiological process activated by diverse cardiac stress, which impairs cardiac function and leads to adverse clinical outcome. This remodeling partly attributes to cardiac fibrosis, which is a result of differentiation of cardiac fibroblasts to myofibroblasts and the production of excessive extracellular matrix within the myocardium. Non-coding RNAs mainly include microRNAs and long non-coding RNAs. These non-coding RNAs have been proved to have a profound impact on biological behaviors of various cardiac cell types and play a pivotal role in the development of cardiac fibrosis. This review aims to summarize the role of microRNAs and long non-coding RNAs in cardiac fibrosis associated with pressure overload, ischemia, diabetes mellitus, aging, atrial fibrillation and heart transplantation, meanwhile shed light on the diagnostic and therapeutic potential of non-coding RNAs for cardiac fibrosis.

Silencing of TLR4 Inhibits Atrial Fibrosis and Susceptibility to Atrial Fibrillation via Downregulation of NLRP3-TGF-β in Spontaneously Hypertensive Rats

Introduction. This study was aimed at exploring whether silencing of TLR4 could inhibit atrial fibrosis and susceptibility to atrial fibrillation (AF) by regulating NLRP3-TGF-β in hypertensive rats. Methods. Spontaneously hypertensive rats (SHRs) were transfected with either a virus containing TLR4-shRNA to downregulate TLR4 or an empty virus (vehicle) at the age of 14 weeks. Fibrosis of left atrium and susceptibility to AF were detected, and expression of NLRP3-TGF-β in left atrial tissue at 22 weeks of age was measured. Primary cardiac fibroblasts were transfected with TLR4-shRNA or scrambled vehicle and stimulated with angiotensin (Ang) II. Proliferation of cardiac fibroblasts and expression of NLRP3-TGF-β were detected. Results. Silencing of TLR4 reduced left atrial fibrosis and susceptibility to AF in SHRs and downregulated expression of NLRP3, TGF-β, and collagen I. In vitro, TLR4 silencing reduced proliferation of cardiac fibroblasts induced by Ang II as well as expression of NLRP3, TGF-β, and collagen I. Conclusion. Silencing of TLR4 can downregulate NLRP3-TGF-β to reduce atrial fibrosis and susceptibility to AF in SHRs.

The Traditional Chinese Medicine Formula FTZ Protects against Cardiac Fibrosis by Suppressing the TGFβ1-Smad2/3 Pathway

Background

Fu fang Zhen Zhu Tiao Zhi (FTZ) is a patented preparation of Chinese herbal medicine that has been used as a natural medicine to treat several chronic diseases including cardiovascular disease. However, its effects on cardiac fibrosis remain unclear. Therefore, this study was designed to investigate the effects and potential mechanisms of FTZ in treating cardiac fibrosis.

Methods

FTZ was administered to mice by oral gavage daily at a dosage of 1.2 g/kg or 2.4 g/kg of body weight for 7 weeks after a transverse aorta constriction (TAC) surgery. Doppler echocardiography, hematoxylin and eosin staining, and Masson's trichrome staining were used to assess the effect of FTZ on the cardiac structure and function of mice that had undergone TAC. EdU and wound-healing assays were performed to measure the proliferative and migratory abilities of cardiac fibroblasts. Western blotting and qRT-PCR were used to determine the expression of TGFβ1, Col1A2, Col3, and α-SMA proteins and mRNA levels.

Results

FTZ treatment reduced collagen synthesis, attenuated cardiac fibrosis, and improved cardiac function in mice subjected to TAC. Moreover, FTZ treatment prevented the proliferation and migration of cardiac fibroblasts and reduced Ang-II-induced collagen synthesis. Furthermore, FTZ downregulated the expression of TGFβ1, p-smad2, and p-smad3 and inhibited the TGFβ1-Smad2/3 pathway in the setting of cardiac fibrosis.

Conclusion

FTZ alleviated the proliferation and migration of cardiac fibroblasts and suppressed collagen synthesis via the TGFβ1-Smad2/3 pathway during the progression of cardiac fibrosis. These findings indicated the therapeutic potential of FTZ in treating cardiac fibrosis.

MicroRNA-577 aggravates bone loss and bone remodeling by targeting thyroid stimulating hormone receptor in hyperthyroid-associated osteoporosis

Traditionally, hyperthyroid-associated osteoporosis has been considered to be the result of increased thyroid hormone levels. The pathogenesis of hyperthyroid-associated osteoporosis remains unclear. Thyroid stimulating hormone receptor (TSHR) is closely associated with osteoporosis. Our study aimed to explore the role of TSHR and its upstream microRNA (miRNA) in hyperthyroid-associated osteoporosis. Bioinformatics analysis (starBase and Targetscan) and a wide range of experiments including reverse-transcription quantitative polymerase chain reaction, luciferase reporter, western blot analysis of osteogenic differentiation markers including OSX, OCN, ALP, OPN, and COL1, hematoxylin and eosin staining, Alizarin Red staining assays were used to explore the function and mechanism of TSHR in hyperthyroid-associated osteoporosis. First, we observed that TSHR was downregulated in bone marrow mesenchymal stem cells (BMSCs) isolated from rats after culture in osteogenic medium for 7 days. Functionally, overexpression of TSHR accelerates BMSC osteogenic differentiation. Mechanistically, we predicted four potential miRNAs for TSHR. MiR-577 was validated to bind with TSHR. Rescue assays showed that miR-577 overexpression inhibited BMSC osteogenic differentiation via targeting TSHR. In vivo experiments showed that miR-577 aggravated bone loss and bone remodeling and our data showed that it is achieved by targeting TSHR in hyperthyroid-associated osteoporosis. This finding may deep our understanding of the pathogenesis of hyperthyroid-associated osteoporosis.

Protein phosphatase 1 regulatory inhibitor subunit 14C promotes triple-negative breast cancer progression via sustaining inactive glycogen synthase kinase 3 beta

Triple-negative breast cancer (TNBC) is fast-growing and highly metastatic with the poorest prognosis among the breast cancer subtypes. Inactivation of glycogen synthase kinase 3 beta (GSK3β) plays a vital role in the aggressiveness of TNBC; however, the underlying mechanism for sustained GSK3β inhibition remains largely unknown. Here, we find that protein phosphatase 1 regulatory inhibitor subunit 14C (PPP1R14C) is upregulated in TNBC and relevant to poor prognosis in patients. Overexpression of PPP1R14C facilitates cell proliferation and the aggressive phenotype of TNBC cells, whereas the depletion of PPP1R14C elicits opposite effects. Moreover, PPP1R14C is phosphorylated and activated by protein kinase C iota (PRKCI) at Thr73. p-PPP1R14C then represses Ser/Thr protein phosphatase type 1 (PP1) to retain GSK3β phosphorylation at high levels. Furthermore, p-PPP1R14C recruits E3 ligase, TRIM25, toward the ubiquitylation and degradation of non-phosphorylated GSK3β. Importantly, the blockade of PPP1R14C phosphorylation inhibits xenograft tumorigenesis and lung metastasis of TNBC cells. These findings provide a novel mechanism for sustained GSK3β inactivation in TNBC and suggest that PPP1R14C might be a potential therapeutic target.

MiRNA-339-5p promotes isoproterenol-induced cardiomyocyte hypertrophy by targeting VCP to activate the mTOR signaling

MicroRNAs (miRNAs) regulate multiple biological processes and participate in various cardiovascular diseases. This study aims to investigate the role of miR-339-5p in cardiomyocyte hypertrophy and the involved mechanism. Neonatal rat cardiomyocytes (NRCMs) were cultured and stimulated with isoproterenol (ISO). The hypertrophic responses were monitored by measuring the cell surface area and expression of hypertrophic markers including β-myosin heavy chain (β-MHC) and atrial natriuretic factor (ANF). Bioinformatic prediction tools and dual-luciferase reporter assay were performed to identify the target gene of miR-339-5p. Quantitative real-time polymerase chain reaction and western blot analysis were used to determine the levels of miR-339-5p and its downstream effectors. Our data showed that miR-339-5p was upregulated during cardiomyocyte hypertrophy triggered by ISO. MiR-339-5p overexpression resulted in enlargement of cell size and increased the levels of hypertrophic markers. In contrast, inhibition of miR-339-5p significantly attenuated ISO-induced hypertrophic responses of NRCMs. Valosin-containing protein (VCP), a suppressor of cardiac hypertrophy via inhibiting mechanistic target of rapamycin (mTOR) signaling, was validated as a target of miR-339-5p. MiR-339-5p suppressed VCP protein expression, leading to elevated phosphorylation of mTOR and ribosomal protein S6 kinase (S6K). VCP depletion activated the mTOR/S6K cascade and could compromise the anti-hypertrophic effects of miR-339-5p inhibitor. Additionally, the hypertrophic responses caused by miR-339-5p was alleviated in the presence of mTOR inhibitor rapamycin. In conclusion, our research revealed that miR-339-5p promoted ISO-induced cardiomyocyte hypertrophy by targeting VCP to activate the mTOR signaling, suggesting a promising therapeutic intervention by interfering miR-339-5p.

Epigenetic regulation in fibrosis progress

Fibrosis, a common process of chronic inflammatory diseases, is defined as a repair response disorder when organs undergo continuous damage, ultimately leading to scar formation and functional failure. Around the world, fibrotic diseases cause high mortality, unfortunately, with limited treatment means in clinical practice. With the development and application of deep sequencing technology, comprehensively exploring the epigenetic mechanism in fibrosis has been allowed. Extensive remodeling of epigenetics controlling various cells phenotype and molecular mechanisms involved in fibrogenesis was subsequently verified. In this review, we summarize the regulatory mechanisms of DNA methylation, histone modification, noncoding RNAs (ncRNAs) and N6-methyladenosine (m6A) modification in organ fibrosis, focusing on heart, liver, lung and kidney. Additionally, we emphasize the diversity of epigenetics in the cellular and molecular mechanisms related to fibrosis. Finally, the potential and prospect of targeted therapy for fibrosis based on epigenetic is discussed.

Serum extracellular vesicles containing MIAT induces atrial fibrosis, inflammation and oxidative stress to promote atrial remodeling and atrial fibrillation via blockade of miR-485-5p-mediated CXCL10 inhibition

BACKGROUND

Atrial fibrillation (AF), a supraventricular arrhythmia that impairs cardiac function, is a main source of morbidity and mortality. Serum-derived extracellular vesicles (EVs) have been identified to carry potential biomarker or target for the diagnosis and treatment of AF. We intended to dissect out the role of lncRNA MIAT enriched in serum-derived EVs in AF.

METHODS

MIAT expression was quantified in EVs isolated from serum samples of AF patients. Mouse and cell models of AF were developed after angiotensin II (Ang II) induction. Relationship between MIAT, miR-485-5p, and CXCL10 was identified. Ectopic expression and depletion assays were implemented in Ang II-treated mice or HL-1 cells, or those co-cultured with serum-derived EVs to explore the roles of EV-carried MIAT.

RESULTS

MIAT was upregulated in EVs from serum samples of AF patients. Further analysis indicated that MIAT enriched in serum-derived EVs promoted atrial fibrosis, inflammation and oxidative stress, and aggravated the atrial remodeling and resultant AF. Mechanistically, MIAT bound to miR-485-5p and weakened its inhibitory role on the target CXCL10, which was responsible for the role of serum-derived EV containing MIAT in cellular fibrosis, oxidative stress and inflammation, and atrial remodeling in vivo.

CONCLUSIONS

In conclusion, serum-derived EV containing MIAT facilitates atrial remodeling and exacerbates the AF by abolishing the miR-485-5p-mediated CXCL10 inhibition. This finding aids in the deeper understanding about the pathophysiology of AF.

Roles of MicroRNAs in Glucose and Lipid Metabolism in the Heart

MicroRNAs (miRNAs) are small non-coding RNAs that participate in heart development and pathological processes mainly by silencing gene expression. Overwhelming evidence has suggested that miRNAs were involved in various cardiovascular pathological processes, including arrhythmias, ischemia-reperfusion injuries, dysregulation of angiogenesis, mitochondrial abnormalities, fibrosis, and maladaptive remodeling. Various miRNAs could regulate myocardial contractility, vascular proliferation, and mitochondrial function. Meanwhile, it was reported that miRNAs could manipulate nutrition metabolism, especially glucose and lipid metabolism, by regulating insulin signaling pathways, energy substrate transport/metabolism. Recently, increasing studies suggested that the abnormal glucose and lipid metabolism were closely associated with a broad spectrum of cardiovascular diseases (CVDs). Therefore, maintaining glucose and lipid metabolism homeostasis in the heart might be beneficial to CVD patients. In this review, we summarized the present knowledge of the functions of miRNAs in regulating cardiac glucose and lipid metabolism, as well as highlighted the miRNA-based therapies targeting cardiac glucose and lipid metabolism.

Targeting Glycogen Synthase Kinase 3 Beta Regulates CD47 Expression After Myocardial Infarction in Rats via the NF-κB Signaling Pathway

The aim of this study was to investigate the effects of the GSK-3β/NF-κB pathway on integrin-associated protein (CD47) expression after myocardial infarction (MI) in rats. An MI Sprague Dawley rat model was established by ligating the left anterior descending coronary artery. The rats were divided into three groups: Sham, MI, and SB + MI (SB216763) groups. Immunohistochemistry was used to observe the changes in cardiac morphology. A significant reduction in the sizes of fibrotic scars was observed in the SB + MI group compared to that in the MI group. SB216763 decreased the mRNA and protein expression of CD47 and NF-κB during MI. Primary rat cardiomyocytes (RCMs) and the H9c2 cell line were used to establish in vitro hypoxia models. Quantitative real-time PCR and western blotting analyses were conducted to detect mRNA and protein expression levels of CD47 and NF-κB and apoptosis-related proteins, respectively. Apoptosis of hypoxic cells was assessed using flow cytometry. SB216763 reduced the protein expression of CD47 and NF-κB in RCMs and H9c2 cells under hypoxic conditions for 12 h, and alleviated hypoxia-induced apoptosis. SN50 (an NF-κB inhibitor) also decreased CD47 protein expression in RCMs and H9c2 cells under hypoxic conditions for 12 h and protected cells from apoptosis. GSK-3β upregulates CD47 expression in cardiac tissues after MI by activating NF-κB, which in turn leads to myocardial cell damage and apoptosis.

Promoting roles of KLF5 in myocardial infarction in mice involving microRNA-27a suppression and the following GFPT2/TGF-β/Smad2/3 axis activation

Myocardial infarction (MI) is a major atherosclerotic cardiovascular disease which represents a leading cause of death worldwide. Kruppel-like factor 5 (KLF5) is a member of the kruppel-like transcription factor family which has been reported with pro-apoptotic functions in myocardial cells. This work focuses on the function of KLF5 in the pathogenesis of MI and the molecules involved. A mouse model with MI was established. Hypoxia/reoxygenation (H/R)-treated H9C2 cells were applied for in vitro experiments. A KLF5-specific inhibitor ML264 was administrated in cell and animal models. ML264 significantly reduced apoptosis, expression of fibrosis-related markers, reactive oxygen species in the H/R-treated H9C2 cells, and it reduced myocardial injury, infarct size, apoptosis and fibrosis in the myocardial tissues in model mice through specific downregulation of KLF5. A microRNA (miRNA) microarray analysis was performed, which suggested miR-27a as the most upregulated miRNA in the H/R-treated cells after ML264 treatment. miR-27a mimic reduced apoptosis and fibrosis in H/R-treated cells, while miR-27a inhibition blocked the protective roles of ML264. The integrated bioinformatic analyses and luciferase assays confirmed glutamine fructose-6-phosphate transaminase 2 (GFPT2) mRNA as a target of miR-27a. Overexpression of GFPT2 counteracted the protective functions of miR-27a against MI through the activation of the TGF-β/Smad2/3 signaling pathway. To conclude, this study evidenced that KLF5 possibly induces cell and tissue damage in MI through downregulation of miR-27a and the subsequent activation of GFPT2/TGF-β/Smad2/3 axis. This study may offer novel thoughts into MI treatment.