MicroRNA-24-3p alleviates cardiac fibrosis by suppressing cardiac fibroblasts mitophagy via downregulating PHB2

LuQi formula ameliorates pressure overload-induced heart failure by regulating macrophages and regulatory T cells

BACKGROUND

Inflammatory macrophages in failing myocardium secrete CCL17, which targets CCR4 in immunosuppressive Tregs and inhibits the intracellular second messenger ARRB2-mediated cardiac chemotaxis. Traditional Chinese medicine (TCM) LuQi formula (LQF) is safe and effective in treating heart failure (HF). This study aims to elucidate the cardioprotective mechanism of LQF through its modulation of cardiac macrophages and Tregs.

METHODS

In vivo, the HF mouse model was established via transverse aortic constriction (TAC), with the superagonistic anti-CD28 monoclonal antibody (CD28-SA)-induced Tregs expansion as a positive control. Proteomics analysis elucidated the core link of LQF in anti-HF. In vitro, bone marrow-derived macrophages (BMDMs) were isolated, and Naive CD4+T cells were sorted and stimulated to differentiate into Tregs. The pharmacological mechanism of LQF was confirmed through histological and molecular biology experiments.

RESULTS

Proteomics reveals that LQF modulates the immune microenvironment of failing myocardium. We revealed that LQF inhibited cardiac inflammatory macrophage infiltration and NF-κB (p50, p65)/CCL17 axis expression, and promoted cardiac Tregs recruitment against HF, with the comparable efficacy of CD-SA28-induced Tregs expansion. Mechanistically, LQF inhibited the NF-κB activator 1-induced NF-κB (p50, p65)/CCL17 axis overexpression, and JSH-23 (NF-κB Inhibitor) abolished NF-κB (p50, p65)/CCL17 axis expression in inflammatory macrophages. Furthermore, the inhibition of CCL17 expression in inflammatory macrophages by LQF was found to be mediated by NF-κB (p50, p65). LQF concentration-dependently promoted Tregs CD73/Foxp3 axis expression, enhancing Tregs immunosuppressive function. LQF activated CCR4-ARRB2 complex and CCR4/ARRB2 axis expression in Tregs. Although AZD2098 (CCR4 Inhibitor) blocked CCR4 expression and CCR4-ARRB2 complex, LQF promoted ARRB2-mediated Tregs cardiac chemotaxis independent of the CCR4. We revealed that NF-κB p50SEP337-CCL17, NF-κB p65SEP536-CCL17, and CCR4-ARRB2 highly bound subunit interface targets. Molecular docking analysis demonstrated that the LQF's active ingredients exhibit good binding affinity with the NF-κB (p50, p65) /CCL17 axis in macrophages and Foxp3 in Tregs.

CONCLUSION

LQF has the potential to enhance the cardiac immune microenvironment and effectively prevent and treat HF by modulating both innate and adaptive immune responses. It achieves this by inhibiting the infiltration of inflammatory macrophages, suppressing the NF-κB (p50, p65)/CCL17 axis, and promoting Tregs recruitment. The active ingredients of LQF provide valuable candidate compounds for developing new anti-HF drugs. Furthermore, CD-28SA-induced Tregs expansion showed cardioprotective effects in TAC-induced non-ischemic HF models.

YTHDF3-mediated FLCN/cPLA2 axis improves cardiac fibrosis via suppressing lysosomal function

Cardiac fibrosis characterized by aberrant activation of cardiac fibroblasts impairs cardiac contractile and diastolic functions, inducing the progression of the disease towards its terminal phase, resulting in the onset of heart failure. Therefore, the inhibition of cardiac fibrosis has become a promising treatment for cardiac diseases. The ovarian follicle-stimulating hormone folliculin (FLCN) plays a significant role in various biological processes, such as lysosome function, mitochondrial synthesis, angiogenesis, ciliogenesis and autophagy. Severe heart failure was observed in FLCN knockout mice. In this study, we investigated the role of FLCN in cardiac fibrosis and its potential mechanisms. The mice were subjected to transverse aortic constriction (TAC) surgery. Myocardial fibrosis developed in the mice 8 weeks after surgery. We showed that the protein and mRNA expression levels of FLCN were significantly decreased in TAC mice. Similar results were observed in primary mouse cardiac fibroblasts treated with Ang-II, an in vitro cardiac fibrosis model, suggesting that FLCN is involved in the pathological process of cardiac fibrosis. We demonstrated that overexpression of FLCN inhibited lysosome function in cardiac fibroblasts. Furthermore, overexpression of FLCN protected the heart from TAC-induced pathological cardiac fibrosis. We revealed that FLCN bound to the cPLA2 protein, increased its activity, regulated lysosomal function, and promoted membrane permeabilisation in cardiac fibroblasts during cardiac fibrosis. Knockdown of cPLA2 blocked the antifibrotic effect of FLCN in cardiac fibrosis. In addition, we found that the reduced expression of FLCN in cardiac fibrosis resulted from the modulation of YTHDF3-regulated m6A methylation of FLCN mRNA. The overexpression of YTHDF3 alleviated the production of collagens and improved cardiac structure and function in TAC mice. YTHDF3 inhibited proliferation and differentiation and regulated lysosomal function in mouse cardiac fibroblasts, whereas these effects were abolished by FLCN knockdown. We conclude that FLCN undergoes YTHDF3-regulated m6A modification and interacts with cPLA2 to improve lysosomal function in cardiac fibroblasts, highlighting its role in myocardial fibrosis therapy. These results suggest that FLCN and YTHDF3 could serve as potential therapeutic targets for cardiac fibroblast treatment.

Bone marrow mesenchymal stem cells-derived exosomal miR-24-3p alleviates spinal cord injury by targeting MAPK9 to inhibit the JNK/c-Jun/c-Fos pathway

Spinal cord injury (SCI) is a very harmful neurological disease that can cause serious damage to sensation, movement, and autonomic nervous function below the affected area. Apoptosis and inflammatory response play important roles in the pathological process of spinal cord injury. The exosomes secreted by bone marrow mesenchymal stem cells (BMSCs) may play a protective role against spinal cord injury. However, the detailed mechanism behind this is not fully understood. The main objective of this study was to investigate the anti-inflammatory and anti-apoptotic effects of bone marrow mesenchymal stem cell exosomes (BMSCs-EXO) in SCI in vitro and in vivo and their mechanisms. The study demonstrated that bone marrow mesenchymal stem cells reduced apoptosis and inflammation and promoted axon growth in LPS-treated PC12 cells. The miRDB predicted that miR-24-3p targets MAPK9(JNK2). Transcriptome sequencing and Western blot confirmed that miR-24-3p inhibits the JNK/c-Jun/c-Fos pathway by targeting MAPK9. In vivo experiments, injection of BMSC exosomes overexpressing miR-24-3p from the tail vein attenuated the SCI exercise injury-related behavior in rats. In conclusion, this study indicates that bone marrow MSC-derived exosomes can mitigate SCI-related injury by suppressing apoptosis and inflammation, with miR-24-3p playing a crucial role, potentially offering a novel therapeutic approach for SCI treatment.

miR-24-3p secreted as extracellular vesicle cargo by cardiomyocytes inhibits fibrosis in human cardiac microtissues

AIMS

Cardiac fibrosis in response to injury leads to myocardial stiffness and heart failure. At the cellular level, fibrosis is triggered by the conversion of cardiac fibroblasts (CF) into extracellular matrix-producing myofibroblasts. miR-24-3p regulates this process in animal models. Here, we investigated whether miR-24-3p plays similar roles in human models.

METHODS AND RESULTS

Gain- and loss-of-function experiments were performed using human induced pluripotent stem cell-derived cardiomyocytes (hCM) and primary hCF under normoxic or ischaemia-simulating conditions. hCM-derived extracellular vesicles (EVs) were added to hCF. Similar experiments were performed using three-dimensional human cardiac microtissues and ex vivo cultured human cardiac slices. hCF transfection with miR-24-3p mimic prevented TGFβ1-mediated induction of FURIN, CCND1, and SMAD4-miR-24-3p target genes participating in TGFβ1-dependent fibrogenesis-regulating hCF-to-myofibroblast conversion. hCM secreted miR-24-3p as EV cargo. hCM-derived EVs modulated hCF activation. Ischaemia-simulating conditions induced miR-24-3p depletion in hCM-EVs and microtissues. Similarly, hypoxia down-regulated miR-24-3p in cardiac slices. Analyses of clinical samples revealed decreased miR-24-3p levels in circulating EVs in patients with acute myocardial infarction (AMI), compared with healthy subjects. Post-mortem RNAScope analysis showed miR-24-3p down-regulation in myocardium from patients with AMI, compared with patients who died from non-cardiac diseases. Berberine, a plant-derived agent with miR-24-3p-stimulatory activity, increased miR-24-3p contents in hCM-EVs, down-regulated FURIN, CCND1, and SMAD4, and inhibited fibrosis in cardiac microtissues.

CONCLUSION

These findings suggest that hCM may control hCF activation through miR-24-3p secreted as EV cargo. Ischaemia impairs this mechanism, favouring fibrosis.

Decoding the regulatory roles of circular RNAs in cardiac fibrosis

Cardiovascular diseases (CVDs) are the primary cause of death globally. The evolution of nearly all types of CVDs is characterized by a common theme: the emergence of cardiac fibrosis. The precise mechanisms that trigger cardiac fibrosis are still not completely understood. In recent years, a type of non-coding regulatory RNA molecule known as circular RNAs (circRNAs) has been reported. These molecules are produced during back splicing and possess significant biological capabilities, such as regulating microRNA activity, serving as protein scaffolds and recruiters, competing with mRNA, forming circR-loop structures to modulate transcription, and translating polypeptides. Furthermore, circRNAs exhibit a substantial abundance, notable stability, and specificity of tissues, cells, and time, endowing them with the potential as biomarkers, therapeutic targets, and therapeutic agents. CircRNAs have garnered growing interest in the field of CVDs. Recent investigations into the involvement of circRNAs in cardiac fibrosis have yielded encouraging findings. This study aims to provide a concise overview of the existing knowledge about the regulatory roles of circRNAs in cardiac fibrosis.

Mechanistic insight into the role of cardiac-enriched microRNAs in diabetic heart injury

Cardiovascular complications, particularly diabetic cardiomyopathy (DCM), are the primary causes of morbidity and mortality among individuals with diabetes. Hyperglycemia associated with diabetes leads to cardiomyocyte hypertrophy, apoptosis, and myocardial fibrosis, culminating in heart failure (HF). Patients with diabetes face a 2-4 times greater risk of developing HF compared with those without diabetes. Consequently, there is a growing interest in exploring the molecular mechanisms that contribute to the development of DCM. MicroRNAs (miRNAs) are short, single-stranded, noncoding RNA molecules that participate in the maintenance of physiological homeostasis through the regulation of essential processes such as metabolism, cell proliferation, and apoptosis. At the posttranscriptional level, miRNAs modulate gene expression by binding directly to genes' mRNAs. Multiple cardiac-enriched miRNAs were reported to be dysregulated under diabetic conditions. Different studies revealed the role of specific miRNAs in the pathogenesis of diabetes and related cardiovascular complications, including cardiomyocyte hypertrophy and fibrosis, mitochondrial dysfunction, metabolic impairment, inflammatory response, or cardiomyocyte death. Circulating miRNAs have been shown to represent the potential biomarkers for early detection of diabetic heart injury. A deeper understanding of miRNAs and their role in diabetes-related pathophysiological processes could lead to new therapeutic strategies for addressing cardiac complications associated with diabetes.

Epigenetic regulation by naringenin and naringin: A literature review focused on the mechanisms underlying its pharmacological effects

Epigenetics refers to heritable changes in gene expression or phenotypic changes that occur without changing the gene sequence. The main methods of epigenetics include non-coding RNA, histone modification, and DNA modification, which play an essential role in gene expression regulation and even the occurrence of diverse diseases. Naringenin, the aglycone form of naringin, is a natural flavonoid compound mainly found in fruits or plant derivatives such as citrus, tomatoes, and cherries. Naringenin and naringin exhibit a broad spectrum of biological activities and pharmacological effects, including anti-cancer, cardiovascular disease improving, anti-inflammatory, and anti-oxidant activities, all of which are advantageous for human health. Recent studies have uncovered that naringenin and naringin influence gene expression by modulating epigenetic pathways, including microRNA (miRNA) regulation. This mechanism plays a crucial role in the therapeutic potential for various diseases. This paper reviews the epigenetic researches on the physiological activities of naringenin and naringin. It highlights how these compounds can exert diverse effects through different signaling pathways, thereby ameliorating associated diseases. These findings provide valuable insights for the future applications of naringenin and naringin.

Targeted mitochondrial function for cardiac fibrosis: An epigenetic perspective

Mitochondria, commonly referred to as "energy factories"of cells, play a crucial role in the function and survival of cardiomyocytes. However, as research on cardiac fibrosis has advanced, mitochondrial dysfunction(including changes in energy metabolism, calcium ion imbalance, increased oxidative stress, and apoptosis)is now recognized as a significant pathophysiological pathway involved in cardiac remodeling and progression, which also negatively affects the function and structure of the heart. In recent years, research focusing on targeting mitochondria has gained significant attention, offering new approaches for treating cardiac fibrosis. Targeted mitochondrial therapy for cardiac fibrosis represents an emerging therapeutic strategy that aims to inhibit cardiac fibroblast proliferation or protect cardiomyocytes from damage by enhancing mitochondrial function. However, current research on epigenetic treatments for cardiac fibrosis through mitochondrial targeting remains limited. This review explores the relationship between mitochondrial dysfunction and cardiac fibrosis, as well as the epigenetic regulatory mechanisms involved in targeted mitochondrial therapy for cardiac fibrosis.

Myocardial ferroptosis may exacerbate the progression of atrial fibrillation through isolevuglandins

Atrial fibrillation (AF) poses a serious health threat to human health and causes various adverse effects. It is currently the most common type of arrhythmia in adults. Long-term AF induces a series of heart-remodeling events, including mainly cardiac structural remodeling and electrical remodeling, which further exacerbates AF. The oxidative stress has been shown to play a role in inducing myocardial remodeling and the progression of AF. Recent studies have shown that ferroptosis occurs in the myocardium of patients with AF, which exacerbates oxidative stress and may constitute a new mechanism for the progression of AF. However, it is unknown to us how ferroptosis is involved in the initiation and maintenance of AF, so the purpose of this review is to elucidate the possible underlying mechanism of ferroptosis exacerbating AF. We reviewed the latest studies on myocardial ferroptosis and AF and speculate that the lipid peroxidation products isolevuglandins (IsoLGs), which are produced during myocardial ferroptosis, may be involved in the progression of AF through two pathways: (1) IsoLGs inhibit the degradation of myocardial collagen, worsening myocardial fibrosis; and (2) IsoLGs promote the occurrence of amyloidosis in the myocardium and increase the risk of AF. Consequently, we aim to prevent the progression of atrial fibrillation by either suppressing the production of IsoLGs or enhancing their clearance process to inhibit ferroptosis in the myocardium, improving the prognosis of patients with AF.

MicroRNA-197-3p Transfection: Variations in Cardiomyocyte Gene Expression with Anaesthetics Drugs in a Model of Hypoxia/Reperfusion

Background: Our research team analyzed the microRNA (miRNA)-197-3p involved in cardioprotection, and we demonstrated that the overexpression of miRNA-197-3p could be linked to a higher risk of cardiac damage. Recent research indicated that miRNA-197-3p inhibits the effector proteins of the anaesthetic preconditioning mechanism of halogenated drugs. In this scenario, we proposed to determine the role of miRNA-197-3p in cardiac injury and its effects on myocardial conditioning under halogenated exposure. Hypothesis: Patients having myocardial revascularization surgery have increased heart damage due to postoperative miRNA-197-3p upregulation. Methods: Human cardiac myocytes (HCMs) were used in an in vitro hypoxia/reperfusion (H/R) model. The miRNA-197-3p-MIMIC was transfected into the HCMs. Three H/R-induced HCM groups were performed: negative MIMIC-control transfected, MIMIC transfected, and non-transfected. Each H/R cell group was exposed to Propofol (P), Sevoflurane (S), or non-exposed. Healthy cell cultures were the control group. ELISA assays were used to assess the Akt1 and p53 cell secretion capacity, and the Next Generation Sequencing assay was used to measure the differential expression of miRNA targets. Results: The secretion capacity of H/R-induced HCMs transfected with the MIMIC was higher under sevoflurane exposure regarding Akt-1 cytokine (I/R + S: 0.80 ± 0.06 ng/mL; I/R + P: 0.45 ± 0.28 ng/mL; p > 0.05), and lower regarding p53 cytokine (I/R + S: 38.62 ± 6.93 ng/mL; I/R + P: 43.34 ± 15.20 ng/mL; p > 0.05) compared to propofol. In addition, a significant gene overexpression of five miRNAs, in the sevoflurane group, was linked to cardioprotection: miRNA-29-3p, 24-3p, 21-3p, 532, and miRNA-335-5p. Conclusions: miRNA-197-3p inhibits the cardioprotection induced by halogenated exposure and can be considered a biomarker of cardiac damage. Additional research is required to validate our findings in other clinical settings.

MiR-24-3p modulates cardiac function in doxorubicin -induced heart failure via the Sp1/PI3K signaling pathway

PURPOSE

The goal of this research was to explore the role of miR-24-3p in heart failure (HF), with a focus on its impact on the specificity protein 1 (Sp1)/phosphoinositide 3-kinase (PI3K) pathway.

METHODS

HF rat and HF cell models were established using doxorubicin(Dox). Cardiac function was assessed through echocardiography, while histological changes were observed via hematoxylin-eosin (HE) staining. To further investigate the underlying mechanisms, HF cell models were treated with either an Sp1 inhibitor or a PI3K inhibitor. Additionally, models with miR-24-3p overexpression or silencing were constructed. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were determined by ELISA. Cell apoptosis was evaluated using TUNEL staining, and lactate dehydrogenase (LDH) levels were measured by colorimetry. Reactive oxygen species (ROS) production was analyzed using flow cytometry. Related gene and protein expressions were assessed via qRT-PCR and Western blotting. Finally, the relationship between miR-24-3p and Sp1 was confirmed through dual-luciferase assays.

RESULTS

Dox treatment increased the left ventricular internal diameter (LVIDd) while decreasing ejection fraction (EF) and fractional shortening (FS), leading to disorganized cardiomyocyte arrangement, cellular edema, and necrosis in rats. In HF rats, NT-proBNP, Caspase-3, and miR-24-3p expression levels were elevated, whereas Sp1 and PI3K mRNA and protein expression levels were decreased. Similarly, Dox-induced damage in H9c2 cardiomyocytes resulted in increased NT-proBNP, apoptosis, Caspase-3, LDH, ROS, and miR-24-3p expression, along with decreased Sp1 and PI3K expression. Treatment with either Sp1 or PI3K inhibitors exacerbated the Dox-induced cardiomyocyte damage, further elevating NT-proBNP, apoptosis, Caspase-3, LDH, ROS, and miR-24-3p expression levels. Notably, Sp1 inhibition reduced PI3K expression, and PI3K inhibition, in turn, suppressed Sp1 expression. Overexpression of miR-24-3p worsened Dox-induced cardiomyocyte damage, characterized by increased NT-proBNP, apoptosis, Caspase-3, LDH, and ROS expression, alongside reduced Sp1 and PI3K expression. In contrast, silencing miR-24-3p mitigated these detrimental effects and increased Sp1 and PI3K expression. Dual-luciferase assays confirmed that miR-24-3p directly targets Sp1.

CONCLUSION

Dox induces cardiomyocyte damage, impairs cardiac function, and promotes cardiomyocyte apoptosis and oxidative stress. Silencing miR-24-3p offers a protective effect by activating the Sp1/PI3K signaling pathway in heart failure.

MicroRNA-24 therapeutic potentials in infarction, stroke, and diabetic complications

The prevalence of cardiovascular events, stroke, and diabetes worldwide underscores the urgent need for effective and minimally invasive treatments. With nearly 20 million annual casualties attributed to cardiovascular diseases and an estimated 463 million people living with diabetes in 2022. Identifying promising therapeutic candidates is paramount. MicroRNAs, short nucleic acids involved in regulating gene expression, emerge as potential game-changers. Among these, microRNA-24 (miR-24), a hypoxia-sensitive player in endothelial vessels, has protective roles against diverse vascular complications. Following heart infarction and stroke, elevating miR-24 expression proves beneficial by mitigating oxidative stress, inflammation, and apoptosis while enhancing cell survival. It reduces cardiac fibrosis in heart disease, regulates aberrant angiogenesis in cerebral hemorrhagic strokes, and enhances the functionality of cardiomyocytes and brain neurons. In diabetic conditions, augmenting miR-24 expression mitigates complications. Further, being miR-24 also expressed by the skeletal muscle (i.e., myo-miR) in response to exercise, this miRNA may participate in the complex molecular network that systemically spreads the beneficial effects of physical exercise. This review provides a comprehensive vision of the molecular mechanisms underpinning the miR-24 protective effects, offering new insights into its therapeutic potential and proposing a novel avenue for medical intervention.

Exploring the therapeutic mechanisms of heart failure with Chinese herbal medicine: a focus on miRNA-mediated regulation

Heart failure (HF) is a clinical condition caused by abnormalities in the heart's structure or function, primarily manifested as diminished ability of the heart to pump blood, which leads to compensatory activation of neurohormones and increased left ventricular filling pressure. HF is one of the fastest-growing cardiovascular diseases globally in terms of incidence and mortality, negatively impacting patients' quality of life and imposing significant medical and economic burdens. Despite advancements in the treatment of HF, hospitalization and mortality remain rates high. In China, Chinese herbal medicine (CHM) has historically played a prominent role in addressing HF, with significant proven efficacy. MicroRNA (miRNA) exerts a pivotal regulatory influence on the maintenance of regular cardiac activity and the progression of HF. MiRNAs, a category of single-stranded RNA molecules, are characterized by their inability to code for proteins. They regulate gene expression by binding to the 3'-untranslated region (3'-UTR) of target mRNAs, thereby influencing the onset and progression of various diseases. Abnormal expression of specific miRNAs is closely associated with HF pathological processes, such as cardiomyocyte apoptosis, myocardial fibrosis, and cardiac hypertrophy. This abnormal expression can influence the pathological progression of HF through the regulation of miRNA expression. This article reviews the regulatory role of miRNAs in HF pathology discusses how CHM compounds and their active ingredients can ameliorate HF pathology through the regulation of miRNA expression. In conclusion, miRNAs represent promising therapeutic targets for HF, and CHM provides a novel strategy for treatment through the regulation of miRNA expression. Future studies must delve deeper into the precise mechanisms by which CHM modulates miRNAs and fully explore its potential for clinical application in HF treatment.

PHB2 alleviates retinal pigment epithelium cell fibrosis by suppressing the AGE-RAGE pathway

Fibrosis is the primary cause of retinal detachment and visual decline. Here, we investigated the role of Prohibitin 2 (PHB2) in modulating fibrosis in ARPE-19 cells stimulated by transforming growth factor (TGF)-β2. The proliferation, migration, and apoptosis of ARPE-19 cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, and flow cytometry assays, and levels of fibrosis-associated and pathway-related proteins were determined by performing western blotting. To examine the mechanisms underlying ARPE-19 cell fibrosis, we performed RNA sequencing, protein-protein interaction network, and enrichment analyses. We detected increases in the expression of the fibrosis-related proteins fibronectin and collagen I in response to TGF-β2 treatment, whereas the expression of PHB2 was downregulated. PHB2 overexpression suppressed the proliferation and migration of TGF-β2-stimulated ARPE-19 cells, promoted apoptosis, and inhibited fibrosis and Smad and non-Smad pathways. PHB2 overexpression inhibited the advanced glycation end-product (AGE)-receptor of advanced glycation end-product (RAGE) pathway activated by TGF-β2 treatment, which contributed to enhancing the effects of PHB2 on cellular processes, fibrosis, and Smad and non-Smad pathways. Conversely, exogenous application of AGE counteracted the effects of PHB2 overexpression. We conclude that by suppressing the AGE-RAGE pathway, PHB2 exerts an inhibitory effect on TGF-β2-induced fibrosis in ARPE-19 cells.

Current concepts in the epigenetic regulation of cardiac fibrosis

Cardiac fibrosis is a significant driver of congestive heart failure, a syndrome that continues to affect a growing patient population globally. Cardiac fibrosis results from a constellation of complex processes at the transcription, receptor, and signaling axes levels. Various mediators and signaling cascades, such as the transformation growth factor-beta pathway, have been implicated in the pathophysiology of cardiac tissue fibrosis. Our understanding of these markers and pathways has improved in recent years as more advanced technologies and assays have been developed, allowing for better delineation of the crosstalk between specific factors. There is mounting evidence suggesting that epigenetic modulation plays a pivotal role in the progression of cardiac fibrosis. Transcriptional regulation of key pro- and antifibrotic pathways can accentuate or blunt the rate and extent of fibrosis at the tissue level. Exosomes, micro-RNAs, and long noncoding RNAs all belong to factors that can impact the epigenetic signature in cardiac fibrosis. Herein, we comprehensively review the latest literature about exosomes, their contents, and cardiac fibrosis. In doing so, we highlight the specific transcriptional factors with pro- or antifibrotic properties. We also assimilate the data supporting these mediators' potential utility as diagnostic or prognostic biomarkers. Finally, we offer insight into where further work can be done to fill existing gaps to translate preclinical findings better and improve clinical outcomes.

MiR-24 regulates obstructive pulmonary disease in rats via S100A8

PURPOSE

Chronic obstructive pulmonary disease (COPD) is a persistent inflammatory disorder characterized by minor airway inflammation and emphysema involving various cell types and cytokines. MicroRNAs (miRNAs) have emerged as critical regulators in the pathogenesis of lung diseases. This study investigates the impact of microRNA-24 (miR-24) on airway inflammatory responses in a rat model of COPD.

MATERIALS AND METHODS

The model was established by combining cigarette smoke exposure and lipopolysaccharide stimulation, and rat lung tissues were transfected with adeno-associated viruses overexpressing miR-24. Pathological changes in the lung were assessed using hematoxylin and eosin staining. Levels of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-6, and interleukin-8, were measured using enzyme-linked immunosorbent assay. Expression of miR-24 and S100A8 was detected through quantitative reverse transcription PCR, while protein levels of S100A8, Toll-like receptor 4 (TLR4), and myeloid differentiation primary response 88 (MyD88) were assessed using western blotting. Bioinformatics analysis and dual-luciferase reporter assay were performed to determine the relationship between S100A8 and miR-24.

RESULTS

The results demonstrated the downregulation of miR-24 in rats with COPD, and its overexpression resulted in a significant decrease in S1008 mRNA levels. Additionally, the protein level of S100A8 was significantly increased in the lung tissues of COPD rats. The upregulation of miR-24, however, not only inhibited the protein expression of S100A8, TLR4, and MyD88 in lung tissues but also reduced the release of pro-inflammatory cytokines in the plasma and bronchoalveolar lavage fluid, thereby attenuating inflammatory responses and pathological injuries in the lung.

CONCLUSIONS

Our data suggest that miR-24 attenuates airway inflammatory responses in COPD by inhibiting the TLR4/MyD88 pathway via targeting S100A8.

To boldly go where no microRNAs have gone before: spaceflight impact on risk for small-for-gestational-age infants

In the era of renewed space exploration, comprehending the effects of the space environment on human health, particularly for deep space missions, is crucial. While extensive research exists on the impacts of spaceflight, there is a gap regarding female reproductive risks. We hypothesize that space stressors could have enduring effects on female health, potentially increasing risks for future pregnancies upon return to Earth, particularly related to small-for-gestational-age (SGA) fetuses. To address this, we identify a shared microRNA (miRNA) signature between SGA and the space environment, conserved across humans and mice. These miRNAs target genes and pathways relevant to diseases and development. Employing a machine learning approach, we identify potential FDA-approved drugs to mitigate these risks, including estrogen and progesterone receptor antagonists, vitamin D receptor antagonists, and DNA polymerase inhibitors. This study underscores potential pregnancy-related health risks for female astronauts and proposes pharmaceutical interventions to counteract the impact of space travel on female health.

Mitophagy-associated programmed neuronal death and neuroinflammation

Mitochondria are crucial organelles that play a central role in cellular metabolism and programmed cell death in eukaryotic cells. Mitochondrial autophagy (mitophagy) is a selective process where damaged mitochondria are encapsulated and degraded through autophagic mechanisms, ensuring the maintenance of both mitochondrial and cellular homeostasis. Excessive programmed cell death in neurons can result in functional impairments following cerebral ischemia and trauma, as well as in chronic neurodegenerative diseases, leading to irreversible declines in motor and cognitive functions. Neuroinflammation, an inflammatory response of the central nervous system to factors disrupting homeostasis, is a common feature across various neurological events, including ischemic, infectious, traumatic, and neurodegenerative conditions. Emerging research suggests that regulating autophagy may offer a promising therapeutic avenue for treating certain neurological diseases. Furthermore, existing literature indicates that various small molecule autophagy regulators have been tested in animal models and are linked to neurological disease outcomes. This review explores the role of mitophagy in programmed neuronal death and its connection to neuroinflammation.

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.

Phosphoglycerate mutase 5 exacerbates alcoholic cardiomyopathy in male mice by inducing prohibitin-2 dephosphorylation and impairing mitochondrial quality control

BACKGROUND

The induction of mitochondrial quality control (MQC) mechanisms is essential for the re-establishment of mitochondrial homeostasis and cellular bioenergetics during periods of stress. Although MQC activation has cardioprotective effects in various cardiovascular diseases, its precise role and regulatory mechanisms in alcoholic cardiomyopathy (ACM) remain incompletely understood.

METHODS

We explored whether two mitochondria-related proteins, phosphoglycerate mutase 5 (Pgam5) and prohibitin 2 (Phb2), influence MQC in male mice during ACM.

RESULTS

Myocardial Pgam5 expression was upregulated in a male mouse model of ACM. Notably, following ACM induction, heart dysfunction was markedly reversed in male cardiomyocyte-specific Pgam5 knockout (Pgam5cKO) mice. Meanwhile, in alcohol-treated male mouse-derived neonatal cardiomyocytes, Pgam5 depletion preserved cell survival and restored mitochondrial dynamics, mitophagy, mitochondrial biogenesis and the mitochondrial unfolded protein response (mtUPR). We further found that in alcohol-treated cardiomyocyte, Pgam5 binds Phb2 and induces its dephosphorylation at Ser91. Alternative transduction of phospho-mimetic (Phb2S91D) and phospho-defective (Phb2S9A) Phb2 mutants attenuated and enhanced, respectively, alcohol-related mitochondrial dysfunction in cardiomyocytes. Moreover, transgenic male mice expressing Phb2S91D were resistant to alcohol-induced heart dysfunction.

CONCLUSIONS

We conclude that ACM-induced Pgam5 upregulation results in Pgam5-dependent Phb2S91 dephosphorylation, leading to MQC destabilisation and mitochondrial dysfunction in heart. Therefore, modulating the Pgam5/Phb2 interaction could potentially offer a novel therapeutic strategy for ACM in male mice.

HIGHLIGHTS

Pgam5 knockout attenuates alcohol-induced cardiac histopathology and heart dysfunction in male mice. Pgam5 KO reduces alcohol-induced myocardial inflammation, lipid peroxidation and metabolic dysfunction in male mice. Pgam5 depletion protects mitochondrial function in alcohol-exposed male mouse cardiomyocytes. Pgam5 depletion normalises MQC in ACM. EtOH impairs MQC through inducing Phb2 dephosphorylation at Ser91. Pgam5 interacts with Phb2 and induces Phb2 dephosphorylation. Transgenic mice expressing a Ser91 phospho-mimetic Phb2 mutant are resistant to ACM.

Mitophagy modulation for the treatment of cardiovascular diseases

BACKGROUND

Defects of mitophagy, the selective form of autophagy for mitochondria, are commonly observed in several cardiovascular diseases and represent the main cause of mitochondrial dysfunction. For this reason, mitophagy has emerged as a novel and potential therapeutic target.

METHODS

In this review, we discuss current evidence about the biological significance of mitophagy in relevant preclinical models of cardiac and vascular diseases, such as heart failure, ischemia/reperfusion injury, metabolic cardiomyopathy and atherosclerosis.

RESULTS

Multiple studies have shown that cardiac and vascular mitophagy is an adaptive mechanism in response to stress, contributing to cardiovascular homeostasis. Mitophagy defects lead to cell death, ultimately impairing cardiac and vascular function, whereas restoration of mitophagy by specific compounds delays disease progression.

CONCLUSIONS

Despite previous efforts, the molecular mechanisms underlying mitophagy activation in response to stress are not fully characterized. A comprehensive understanding of different forms of mitophagy active in the cardiovascular system is extremely important for the development of new drugs targeting this process. Human studies evaluating mitophagy abnormalities in patients at high cardiovascular risk also represent a future challenge.

Mitochondrial Dysfunction: A Roadmap for Understanding and Tackling Cardiovascular Aging

Cardiovascular aging is a progressive remodeling process constituting a variety of cellular and molecular alterations that are closely linked to mitochondrial dysfunction. Therefore, gaining a deeper understanding of the changes in mitochondrial function during cardiovascular aging is crucial for preventing cardiovascular diseases. Cardiac aging is accompanied by fibrosis, cardiomyocyte hypertrophy, metabolic changes, and infiltration of immune cells, collectively contributing to the overall remodeling of the heart. Similarly, during vascular aging, there is a profound remodeling of blood vessel structure. These remodeling present damage to endothelial cells, increased vascular stiffness, impaired formation of new blood vessels (angiogenesis), the development of arteriosclerosis, and chronic vascular inflammation. This review underscores the role of mitochondrial dysfunction in cardiac aging, exploring its impact on fibrosis and myocardial alterations, metabolic remodeling, immune response remodeling, as well as in vascular aging in the heart. Additionally, we emphasize the significance of mitochondria-targeted therapies in preventing cardiovascular diseases in the elderly.

Palmatine alleviates cardiac fibrosis by inhibiting fibroblast activation through the STAT3 pathway

Cardiac fibrosis, the hallmark of cardiovascular disease, is characterized by excessive deposition of extracellular matrix in the heart. Emerging evidence indicates that cardiac fibroblasts (CFs) play pivotal roles in driving cardiac fibrosis. However, due to incomplete insights into CFs, there are limited effective approaches to prevent or reverse cardiac fibrosis currently. Palmatine, a protoberberine alkaloid extracted from traditional Chinese botanical remedies, possesses diverse biological effects. This study investigated the potential therapeutic value and mechanism of palmatine against cardiac fibrosis. Adult male C57BL/6 mice were treated with vehicle, isoproterenol (ISO), or ISO plus palmatine for one week. After echocardiography assessment, mice hearts were collected for histopathology, real-time polymerase chain reaction, and Western blot analyses. Primary rat CFs were utilized in vitro. Compared to control, ISO-treated mice exhibited cardiac hypertrophy and structural abnormalities; however, treatment with palmatine ameliorated these effects of ISO. Moreover, palmatine treatment mitigated ISO-induced cardiac fibrosis. Network pharmacology and molecular docking analysis showed that palmatine strongly binds the regulators of cardiac fibrosis including signal transducer and activator of transcription 3 (STAT3) and mammalian target of rapamycin. Furthermore, palmatine reduced the elevated fibrotic factor expressions and overactivated STAT3 induced by ISO, Transformed growth factor β1 (TGF-β1), or interleukin-6 both in vivo and in vitro. Additionally, blocking STAT3 suppressed the TGF-β1-induced CF activation. Collectively, these data demonstrated that palmatine attenuated cardiac fibrosis partly by inhibiting fibroblast activation through the STAT3 pathway. This provides an experimental basis for the clinical treatment of cardiac fibrosis with palmatine.

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.

Prohibitin 2: A key regulator of cell function

The PHB2 gene is located on chromosome 12p13 and encodes prohibitin 2, a highly conserved protein of 37 kDa. PHB2 is a dimer with antiparallel coils, possessing a unique negatively charged region crucial for its mitochondrial molecular chaperone functions. Thus, PHB2 plays a significant role in cell life activities such as mitosis, mitochondrial autophagy, signal transduction, and cell death. This review discusses how PHB2 inhibits transcription factors or nuclear receptors to maintain normal cell functions; how PHB2 in the cytoplasm or membrane ensures normal cell mitosis and regulates cell differentiation; how PHB2 affects mitochondrial structure, function, and cell apoptosis through mitochondrial intimal integrity and mitochondrial autophagy; how PHB2 affects mitochondrial stress and inhibits cell apoptosis by regulating cytochrome c migration and other pathways; how PHB2 affects cell growth, proliferation, and metastasis through a mitochondrial independent mechanism; and how PHB2 could be applied in disease treatment. We provide a theoretical basis and an innovative perspective for a comprehensive understanding of the role and mechanism of PHB2 in cell function regulation.

Mitophagy for cardioprotection

Mitochondrial function is maintained by several strictly coordinated mechanisms, collectively termed mitochondrial quality control mechanisms, including fusion and fission, degradation, and biogenesis. As the primary source of energy in cardiomyocytes, mitochondria are the central organelle for maintaining cardiac function. Since adult cardiomyocytes in humans rarely divide, the number of dysfunctional mitochondria cannot easily be diluted through cell division. Thus, efficient degradation of dysfunctional mitochondria is crucial to maintaining cellular function. Mitophagy, a mitochondria specific form of autophagy, is a major mechanism by which damaged or unnecessary mitochondria are targeted and eliminated. Mitophagy is active in cardiomyocytes at baseline and in response to stress, and plays an essential role in maintaining the quality of mitochondria in cardiomyocytes. Mitophagy is mediated through multiple mechanisms in the heart, and each of these mechanisms can partially compensate for the loss of another mechanism. However, insufficient levels of mitophagy eventually lead to mitochondrial dysfunction and the development of heart failure. In this review, we discuss the molecular mechanisms of mitophagy in the heart and the role of mitophagy in cardiac pathophysiology, with the focus on recent findings in the field.

Interference of a mammalian circRNA regulates lipid metabolism reprogramming by targeting miR-24-3p/Igf2/PI3K-AKT-mTOR and Igf2bp2/Ucp1 axis

White adipose tissue (WAT) is important for regulating the whole systemic energy homeostasis. Excessive WAT accumulation further contributes to the development of obesity and obesity-related illnesses. More detailed mechanisms for WAT lipid metabolism reprogramming, however, are still elusive. Here, we report the abnormally high expression of a circular RNA (circRNA) mmu_circ_0001874 in the WAT and liver of mice with obesity. mmu_circ_0001874 interference achieved using a specific adeno-associated virus infects target tissues, down-regulating lipid accumulation in the obesity mice WAT, and liver tissues. Mechanistically, miR-24-3p directly interacts with the lipid metabolism effect of mmu_circ_0001874 and participates in adipogenesis and lipid accumulation by targeting Igf2/PI3K-AKT-mTOR axis. Moreover, mmu_circ_0001874 binds to Igf2bp2 to interact with Ucp1, up-regulating Ucp1 translation and increasing thermogenesis to decrease lipid accumulation. In conclusion, our data highlight a physiological role for circRNA in lipid metabolism reprogramming and suggest mmu_circ_0001874/miR-24-3p/Igf2/PI3K-AKT-mTOR and mmu_circ_0001874/Igf2bp2/Ucp1 axis may represent a potential mechanism for controlling lipid accumulation in obesity.

miRNAs orchestration of cardiovascular diseases - Particular emphasis on diagnosis, and progression

MicroRNAs (miRNAs; miRs) are small non-coding ribonucleic acids sequences vital in regulating gene expression. They are significant in many biological and pathological processes and are even detectable in various body fluids such as serum, plasma, and urine. Research has demonstrated that the irregularity of miRNA in multiplying cardiac cells is linked to developmental deformities in the heart's structure. It has also shown that miRNAs are crucial in diagnosing and progressing several cardiovascular diseases (CVDs). The review covers the function of miRNAs in the pathophysiology of CVD. Additionally, the review provides an overview of the potential role of miRNAs as disease-specific diagnostic and prognostic biomarkers for human CVD, as well as their biological implications in CVD.

Mitochondrial quality control in cardiac fibrosis: Epigenetic mechanisms and therapeutic strategies

Cardiac fibrosis (CF) is considered an ultimate common pathway of a wide variety of heart diseases in response to diverse pathological and pathophysiological stimuli. Mitochondria are characterized as isolated organelles with a double-membrane structure, and they primarily contribute to and maintain highly dynamic energy and metabolic networks whose distribution and structure exert potent support for cellular properties and performance. Because the myocardium is a highly oxidative tissue with high energy demands to continuously pump blood, mitochondria are the most abundant organelles within mature cardiomyocytes, accounting for up to one-third of the total cell volume, and play an essential role in maintaining optimal performance of the heart. Mitochondrial quality control (MQC), including mitochondrial fusion, fission, mitophagy, mitochondrial biogenesis, and mitochondrial metabolism and biosynthesis, is crucial machinery that modulates cardiac cells and heart function by maintaining and regulating the morphological structure, function and lifespan of mitochondria. Certain investigations have focused on mitochondrial dynamics, including manipulating and maintaining the dynamic balance of energy demand and nutrient supply, and the resultant findings suggest that changes in mitochondrial morphology and function may contribute to bioenergetic adaptation during cardiac fibrosis and pathological remodeling. In this review, we discuss the function of epigenetic regulation and molecular mechanisms of MQC in the pathogenesis of CF and provide evidence for targeting MQC for CF. Finally, we discuss how these findings can be applied to improve the treatment and prevention of CF.

Therapeutic potential of urine exosomes derived from rats with diabetic kidney disease

Kidney disease is prevalent in diabetes. Urinary exosomes (uE) from animal models and patients with Diabetic nephropathy (DN) showed increased levels of miRs with reno-protective potential. We examined whether urinary loss of such miRs is associated with their reduced renal levels in DN patients. We also tested whether injecting uE can leverage kidney disease in rats. In this study (study-1) we performed microarray profiling of miRNA in uE and renal tissues in DN patients and subjects with diabetes without DN (controls). In study-2, diabetes was induced in Wistar rats by Streptozotocin (i.p. 50 mg/kg of body weight). Urinary exosomes were collected at 6th, 7th and 8th weeks, and injected back into the rats (100ug/biweekly, uE-treated n=7) via tail vein on weeks 9 and 10. Equal volume of vehicle was injected in controls (vehicle, n=7). uE from the human and rat showed the presence of exosome-specific proteins by immunoblotting. Microarray profiling revealed a set of 15 miRs having high levels in the uE, while lower in renal biopsies, from DN, compared to controls (n=5-9/group). Bioinformatic analysis also confirmed the Renoprotective potential of these miRs. Taqman qPCR confirmed the opposite regulation of miR-200c-3p and miR-24-3p in paired uE and renal biopsy samples from DN patients (n=15), relative to non-DN controls. A rise in 28 miRs levels, including miR-200c-3p, miR-24-3p, miR-30a-3p and miR-23a-3p were observed in the uE of DN rats, collected between 6th-8th weeks, relative to baseline (before diabetes induction). uE- treated DN rats had significantly reduced urine albumin-to-creatinine ratio, attenuated renal pathology, and lower miR-24-3p target fibrotic/inflammatory genes (TGF-beta, and Collagen IV), relative to vehicle treated DN rats. In uE treated rats, the renal expression of miR-24-3p, miR-30a-3p, let-7a-5p and miR-23a-3p was increased, relative to vehicle control. Patients with diabetic nephropathy had reduced renal levels, while higher uE abundance of miRs with reno-protective potential. Reverting the urinary loss of miRs by injecting uE attenuated renal pathology in diabetic rats.

Potential Mechanisms Between HF and COPD: New Insights From Bioinformatics

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) are closely related in clinical practice. This study aimed to investigate the co-genetic characteristics and potential molecular mechanisms of HF and COPD. HF and COPD datasets were downloaded from gene expression omnibus database. After identifying common differentially expressed genes (DEGs), the functional analysis highlighted the critical role of extracellular matrix and ribosomal signaling pathways in both diseases. In addition, GeneMANIA's results suggested that the 2 diseases were related to immune infiltration, and CIBERSORT suggested the role of macrophages. We also discovered 4 TFs and 1408 miRNAs linked to both diseases, and salbutamol may positively affect them.

7,8-Dihydroxyflavone alleviates cardiac fibrosis by restoring circadian signals via downregulating Bmal1/Akt pathway

Brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) pathway is a therapeutic target in cardiac diseases. A BDNF mimetic, 7,8-dihydroxyflavone (7,8-DHF), is emerging as a protective agent in cardiomyocytes; however, its potential role in cardiac fibroblasts (CFs) and fibrosis remains unknown. Thus, we aimed to explore the effects of 7,8-DHF on cardiac fibrosis and the possible mechanisms. Myocardial ischemia (MI) and transforming growth factor-β1 (TGF-β1) were used to establish models of cardiac fibrosis. Hematoxylin & eosin and Masson's trichrome stains were used for histological analysis and determination of collagen content in mouse myocardium. Cell viability kit, EdU (5-ethynyl-2'-deoxyuridine) assay and immunofluorescent stain were employed to examine the effects of 7,8-DHF on the proliferation and collagen production of CFs. The levels of collagen I, α-smooth muscle actin (α-SMA), TGF-β1, Smad2/3, and Akt as well as circadian rhythm-related signals including brain and muscle Arnt-like protein 1 (Bmal1), period 2 (Per2), and cryptochrome 2 (Cry2) were analyzed. Treatment with 7,8-DHF markedly alleviated cardiac fibrosis in MI mice. It inhibited the activity of CFs accompanied by decreasing number of EdU-positive cells and downregulation of collagen I, α-SMA, TGF-β1, and phosphorylation of Smad2/3. 7,8-DHF significantly restored the dysregulation of Bmal1, Per2, and Cry2, but inhibited the overactive Akt. Further, inhibition of Bmal1 by SR9009 effectively attenuated CFs proliferation and collagen production of CFs. In summary, these findings indicate that 7,8-DHF attenuates cardiac fibrosis and regulates circadian rhythmic signals, at least partly, by inhibiting Bmal1/Akt pathway, which may provide new insights into therapeutic cardiac remodeling.

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.

Mitophagy: A Potential Target for Pressure Overload-Induced Cardiac Remodelling

The pathological mechanisms underlying cardiac remodelling and cardiac dysfunction caused by pressure overload are poorly understood. Mitochondrial damage and functional dysfunction, including mitochondrial bioenergetic disorder, oxidative stress, and mtDNA damage, contribute to heart injury caused by pressure overload. Mitophagy, an important regulator of mitochondrial homeostasis and function, is triggered by mitochondrial damage and participates in the pathological process of cardiovascular diseases. Recent studies indicate that mitophagy plays a critical role in the pressure overload model, but evidence on the causal relationship between mitophagy abnormality and pressure overload-induced heart injury is inconclusive. This review summarises the mechanism, role, and regulation of mitophagy in the pressure overload model. It also pays special attention to active compounds that may regulate mitophagy in pressure overload, which provide clues for possible clinical applications.