MicroRNA-20b Promotes Cardiac Hypertrophy by the Inhibition of Mitofusin 2-Mediated Inter-organelle Ca2+ Cross-Talk

13-Methylpalmatine improves myocardial infarction injury by inhibiting CHOP-mediated cross-talk between endoplasmic reticulum and mitochondria

Myocardial infarction (MI) is a leading cause of morbidity and mortality worldwide, and endoplasmic reticulum stress (ERS) and mitochondrial Ca2+ overload have been involved in apoptotic cardiomyocyte death during MI. 13-Methylpalmatine (13-Me-PLT) is a natural isoquinoline alkaloid isolated from Coptis chinensis and has not been systematically studied for their potential pharmacological effects in cardiovascular diseases. We conducted the present study to elucidate whether 13-Me-PLT modulates MI pathology in animal MI and cellular hypoxic models, employing state-of-the-art molecular techniques. The results demonstrated that 13-Me-PLT preserved post-ischemic cardiac function and alleviated cardiomyocyte apoptosis. 13-Me-PLT decreased ERS and the communication between ER and mitochondria, which serves as a protective mechanism against mitochondrial Ca2+ overload and structural and functional injuries to mitochondria. Our data revealed mitigating mitochondrial Ca2+ overload and apoptosis by inhibiting CHOP-mediated Ca2+ transfer between inositol 1,4,5-trisphosphate receptor (IP3R) in ER and VDAC1 in mitochondria as an underlying mechanism for 13-Me-PLT action. Furthermore, 13-Me-PLT produced superior effects in alleviating cardiac dysfunction and apoptosis post-MI to diltiazem and palmatine. Collectively, our research suggests that the CHOP/IP3R/VDAC1 signaling pathway mediates ER-mitochondrial Ca2+ transfer and 13-Me-PLT activates this axis to maintain cellular and organellar Ca2+ homeostasis, protecting against ischemic myocardial injury. These findings may offer an opportunity to develop new agents for the therapy of ischemic heart disease.

Effect of mitochondrial calcium homeostasis-mediated endogenous enzyme activation on tenderness of beef muscle based on MCU modulators

The mitochondrial calcium uniporter (MCU) occupies a noteworthy position in the regulation of mitochondrial calcium uptake. This study investigated the effects of MCU modulator-mediated mitochondrial calcium on mitochondrial dysfunction, oxidative stress, endogenous enzyme activities, and tenderness during postmortem aging. Spermine, as an activator of MCU, resulted in an increase in mitochondrial calcium levels, not only disrupting mitochondrial morphology but also triggering mitochondrial oxidative stress and downregulation of antioxidant factors. Additionally, the spermine group underwent later activation of calpain and earlier activation of caspases, as well as the myofibril fragmentation index was initially lower and then higher compared with control group, indicating that endogenous enzymes played an indispensable role in different aging periods. Interestingly, the results of the Ru360 (an inhibitor of MCU) group were opposite to those aforementioned findings. Our data provide a novel perspective on the regulatory mechanism of mitochondrial calcium homeostasis mediated by MCU on tenderness.

Mitochondrial outer membrane protein MTUS1/ATIP1 exerts antitumor effects through ROS-induced mitochondrial pyroptosis in head and neck squamous cell carcinoma

We showed that microtubule-associated tumor suppressor gene (MTUS1/ATIP) downregulation correlated with poor survival in head and neck squamous cell carcinoma (HNSCC) patients and that MTUS1/ATIP1 was the most abundant isoform in HNSCC tissue. However, the location and function of MTUS1/ATIP1 have remain unclear. In this study, we confirmed that MTUS1/ATIP1 inhibited proliferation, growth and metastasis in HNSCC in cell- and patient-derived xenograft models in vitro and in vivo. MTUS1/ATIP1 localized in the outer mitochondrial membrane, influence the morphology, movement and metabolism of mitochondria and stimulated oxidative stress in HNSCC cells by directly interacting with MFN2. MTUS1/ATIP1 activated ROS, recruiting Bax to mitochondria, facilitating cytochrome c release to the cytosol to activate caspase-3, and inducing GSDME-dependent pyroptotic death in HNSCC cells. Our findings showed that MTUS1/ATIP1 localized in the outer mitochondrial membrane in HNSCC cells and mediated anticancer effects through ROS-induced pyroptosis, which may provide a novel therapeutic strategy for HNSCC treatment.

The crucial relationship between miRNA-27 and CSE/H2S, and the mechanism of action of GLP-1 in myocardial hypertrophy

Cardiac hypertrophy is the most prevalent compensatory heart disease that ultimately leads to spontaneous heart failure. Mounting evidence suggests that microRNAs (miRs) and endogenous hydrogen sulfide (H2S) play a crucial role in the regulation of cardiac hypertrophy. In this study, we aimed to investigate whether inhibition of miR-27a could protect against cardiac hypertrophy by modulating H2S signaling. We established a model of cardiac hypertrophy by obtaining hypertrophic tissue from mice subjected to transverse aortic constriction (TAC) and from cells treated with angiotensin-II. Molecular alterations in the myocardium were quantified using quantitative real time PCR (qRT-PCR), Western blotting, and ELISA. Morphological changes were characterized by hematoxylin and eosin (HE) staining and Masson's trichrome staining. Functional myocardial changes were assessed using echocardiography. Our results demonstrated that miR-27a levels were elevated, while H2S levels were reduced in TAC mice and myocardial hypertrophy. Further luciferase and target scan assays confirmed that cystathionine-γ-lyase (CSE) was a direct target of miR-27a and was negatively regulated by it. Notably, enhancement of H2S expression in the heart was observed in mice injected with recombinant adeno-associated virus vector 9 (rAAV9)-anti-miR-27a and in cells transfected with a miR-27a inhibitor during cardiac hypertrophy. However, this effect was abolished by co-transfection with CSE siRNA and the miR-27a inhibitor. Conversely, injecting rAAV9-miR-27a yielded opposite results. Interestingly, our findings demonstrated that glucagon-like peptide-1 (GLP-1) agonists could mitigate myocardial damage by down-regulating miR-27a and up-regulating CSE. In summary, our study suggests that inhibition of miR-27a holds therapeutic promise for the treatment of cardiac hypertrophy by increasing H2S levels. Furthermore, our findings unveil a novel mechanism of GLP-1 agonists involving the miR-27a/H2S pathway in the management of cardiac hypertrophy.

USP28 Serves as a Key Suppressor of Mitochondrial Morphofunctional Defects and Cardiac Dysfunction in the Diabetic Heart

BACKGROUND

The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy.

METHODS

The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay.

RESULTS

Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2.

CONCLUSIONS

Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.

Cardiac miRNA expression during the development of chronic anthracycline-induced cardiomyopathy using an experimental rabbit model

Background: Anthracycline cardiotoxicity is a well-known complication of cancer treatment, and miRNAs have emerged as a key driver in the pathogenesis of cardiovascular diseases. This study aimed to investigate the expression of miRNAs in the myocardium in early and late stages of chronic anthracycline induced cardiotoxicity to determine whether this expression is associated with the severity of cardiac damage. Method: Cardiotoxicity was induced in rabbits via daunorubicin administration (daunorubicin, 3 mg/kg/week; for five and 10 weeks), while the control group received saline solution. Myocardial miRNA expression was first screened using TaqMan Advanced miRNA microfluidic card assays, after which 32 miRNAs were selected for targeted analysis using qRT-PCR. Results: The first subclinical signs of cardiotoxicity (significant increase in plasma cardiac troponin T) were observed after 5 weeks of daunorubicin treatment. At this time point, 10 miRNAs (including members of the miRNA-34 and 21 families) showed significant upregulation relative to the control group, with the most intense change observed for miRNA-1298-5p (29-fold change, p < 0.01). After 10 weeks of daunorubicin treatment, when a further rise in cTnT was accompanied by significant left ventricle systolic dysfunction, only miR-504-5p was significantly (p < 0.01) downregulated, whereas 10 miRNAs were significantly upregulated relative to the control group; at this time-point, the most intense change was observed for miR-34a-5p (76-fold change). Strong correlations were found between the expression of multiple miRNAs (including miR-34 and mir-21 family and miR-1298-5p) and quantitative indices of toxic damage in both the early and late phases of cardiotoxicity development. Furthermore, plasma levels of miR-34a-5p were strongly correlated with the myocardial expression of this miRNA. Conclusion: To the best of our knowledge, this is the first study that describes alterations in miRNA expression in the myocardium during the transition from subclinical, ANT-induced cardiotoxicity to an overt cardiotoxic phenotype; we also revealed how these changes in miRNA expression are strongly correlated with quantitative markers of cardiotoxicity.

Potential Roles of microRNAs for Assessing Cardiovascular Risk in Pre-Eclampsia-Exposed Postpartum Women and Offspring

Pre-eclampsia, which is part of the spectrum of hypertensive pregnancy disorders, poses a significant health burden, contributing to maternal and infant morbidity and mortality. Pre-eclampsia is widely associated with persistent adverse effects on the cardiovascular health of women with a history of pre-eclampsia. Additionally, there is increasing evidence demonstrating that offspring of pre-eclamptic pregnancies have altered cardiac structure and function, as well as different vascular physiology due to the decrease in endothelial function. Therefore, early detection of the likelihood of developing pre-eclampsia-associated cardiovascular diseases is vital, as this could facilitate the undertaking of the necessary clinical measures to avoid disease progression. The utilisation of microRNAs as biomarkers is currently on the rise as microRNAs have been found to play important roles in regulating various physiological and pathophysiological processes. In regard to pre-eclampsia, recent studies have shown that the expression of microRNAs is altered in postpartum women and their offspring who have been exposed to pre-eclampsia, and that these alterations may persist for several years. This review, therefore, addresses changes in microRNA expression found in postpartum women and offspring exposed to pre-eclampsia, their involvement in cardiovascular disease, and the potential role of microRNAs to be used as predictive tools and therapeutic targets in future cardiovascular disease research.

Increased Ca2 + transport across the mitochondria-associated membranes by Mfn2 inhibiting endoplasmic reticulum stress in ischemia/reperfusion kidney injury

Renal ischemia/reperfusion (I/R) injury, which leads to acute kidney injury (AKI), is a major cause of morbidity and mortality in a variety of clinical situations. This study aimed to investigate the protective role of Mfn2 during renal I/R injury. Overexpression of Mfn2 in NRK-52E rat renal tubular epithelial cells and rats, then we constructed hypoxia reoxygenation (H/R) cells and I/R rat model. Apoptosis, ROS, ATP, Ca2+ levels in cells and rats, as well as renal tissue and functional injury in rats were detected respectively. Endoplasmic reticulum (ER) stress was further examined in cells and rats. The morphological changes of mitochondria-associated ER membranes (MAMs) were also detected. Mfn2 expression is reduced in H/R-treated NRK-52E cells and renal tissue of I/R rats. At the cellular level, overexpression of Mfn2 promoted cell proliferation, inhibited cell apoptosis, attenuated mitochondrial damage and Ca2+ overload, and ER stress. In addition, Mfn2 also restored the MAMs structure. In vivo experiments found that overexpression of Mfn2 could improve renal function and alleviate tissue injury. Concomitant with elevated Mfn2 expression in the kidney, reduced renal cell apoptosis, restored mitochondrial function, and reduced calcium overload. Finally, ER stress in rat kidney tissue was alleviated after overexpression of Mfn2. These results reveal that Mfn2 contributes to ER stress, mitochondrial function, and cell death in I/R injury, which provides a novel therapeutic target for AKI.

Targeting and delivery of microRNA-targeting antisense oligonucleotides in cardiovascular diseases

Discovered three decades ago, microRNAs (miRNAs) are now recognized as key players in the pathophysiology of multiple human diseases, including those affecting the cardiovascular system. As such, miRNAs have emerged as promising therapeutic targets for preventing the onset and/or progression of several cardiovascular diseases. Anti-miRNA antisense oligonucleotides or "antagomirs" precisely block the activity of specific miRNAs and are therefore a promising therapeutic strategy to repress pathological miRNAs. In this review, we describe advancements in antisense oligonucleotide chemistry that have significantly improved efficacy and safety. Moreover, we summarize recent approaches for the targeted delivery of antagomirs to cardiovascular tissues, highlighting major advantages as well as limitations of viral (i.e., adenovirus, adeno-associated virus, and lentivirus) and non-viral (i.e., liposomes, extracellular vesicles, and polymer nanoparticles) delivery systems. We discuss recent preclinical studies that use targeted antagomir delivery systems to treat three major cardiovascular diseases (atherosclerosis, myocardial infarction, and cardiac hypertrophy, including hypertrophy caused by hypertension), highlighting therapeutic results and discussing challenges that limit clinical applicability.

Mechanisms of mitochondrial microRNA regulation in cardiovascular diseases

In the past years, microRNAs (miRNAs) have emerged as important biomarkers and essential regulators of many pathophysiological processes. Several studies have focused on the importance of these noncoding RNAs (ncRNAs) in maintaining mitochondrial function, introducing the term mitochondrial microRNAs (mitomiRs) to refer to those miRNAs controlling mitochondrial activity, either by targeting cytoplasmatic messenger RNAs (mRNAs) or by acting inside the mitochondria. Mitochondrial homeostasis is paramount in the cardiovascular system, where an important energy supply is needed to maintain the homeostasis of tissues, such as the myocardium. In this review, we will address the relevance of mitomiRs in cardiovascular pathologies by dissecting and categorizing their effect in mitochondrial function in order to provide a robust framework for new mitomiR-based therapeutical approaches to this group of diseases.

Angiotensin II-induced calcium overload affects mitochondrial functions in cardiac hypertrophy by targeting the USP2/MFN2 axis

Ubiquitination, a common type of post-translational modification, is known to affect various diseases, including cardiac hypertrophy. Ubiquitin-specific peptidase 2 (USP2) plays a crucial role in regulating cell functions, but its role in cardiac functions remains elusive. The present study aims to investigate the mechanism of USP2 in cardiac hypertrophy. Animal and cell models of cardiac hypertrophy were established using Angiotensin II (Ang II) induction. Our experiments revealed that Ang II induced USP2 downregulation in the in vitro and in vivo models. USP2 overexpression suppressed the degree of cardiac hypertrophy (decreased ANP, BNP, and β-MHC mRNA levels, cell surface area, and ratio of protein/DNA), calcium overload (decreased Ca²⁺ concentration and t-CaMKⅡ and p-CaMKⅡ, and increased SERCA2), and mitochondrial dysfunction (decreased MDA and ROS and increased MFN1, ATP, MMP, and complex Ⅰ and II) both in vitro and in vivo. Mechanically, USP2 interacted with MFN2 and improved the protein level of MFN2 through deubiquitination. Rescue experiments confirmed that MFN2 downregulation neutralized the protective role of USP2 overexpression in cardiac hypertrophy. Overall, our findings suggested that USP2 overexpression mediated deubiquitination to upregulate MFN2, thus alleviating calcium overload-induced mitochondrial dysfunction and cardiac hypertrophy.

Mitochondrial miRNA as epigenomic signatures: Visualizing aging-associated heart diseases through a new lens

Aging bears many hard knocks, but heart disorders earn a particular allusion, being the most widespread. Cardiovascular diseases (CVDs) are becoming the biggest concern to mankind due to sundry health conditions directly or indirectly related to heart-linked abnormalities. Scientists know that mitochondria play a critical role in the pathophysiology of cardiac diseases. Both environment and genetics play an essential role in modulating and controlling mitochondrial functions. Even a minor abnormality may prove detrimental to heart function. Advanced age combined with an unhealthy lifestyle can cause most cardiomyocytes to be replaced by fibrotic tissue which upsets the conducting system and leads to arrhythmias. An aging heart encounters far more heart-associated comorbidities than a young heart. Many state-of-the-art technologies and procedures are already being used to prevent and treat heart attacks worldwide. However, it remains a mystery when this heart bomb would explode because it lacks an alarm. This calls for a novel and effective strategy for timely diagnosis and a sure-fire treatment. This review article provides a comprehensive overture of prospective potentials of mitochondrial miRNAs that predict complicated and interconnected pathways concerning heart ailments and signature compilations of relevant miRNAs as biomarkers to plot the role of miRNAs in epigenomics. This article suggests that analysis of DNA methylation patterns in age-associated heart diseases may determine age-impelled biomarkers of heart disease.

The Role of Mitochondria-Targeting miRNAs in Intracerebral Hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Arterial hypertension (AH) is most often the cause of ICH, followed by atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication and vitamin deficiencies. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. AH is difficult to treat, requires surgery and can lead to disability or death. One of the important directions in the study of the pathogenesis of ICH is mitochondrial dysfunction and its regulation. The key role of mitochondrial dysfunction in AH and atherosclerosis, as well as in the development of brain damage after hemorrhage, has been acknowledged. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that regulate a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., primarily through gene repression. There is growing evidence to support dysregulated miRNAs in various cardiovascular diseases, including ICH. Further, the realization of miRNAs within mitochondrial compartment has challenged the traditional knowledge of signaling pathways involved in the regulatory network of cardiovascular diseases. However, the role of miRNAs in mitochondrial dysfunction for ICH is still under-appreciated, with comparatively much lesser studies and investigations reported, than those in other cardiovascular diseases. In this review, we summarize the up-to-date findings on the published role miRNAs in mitochondrial function for ICH, and the potential use of miRNAs in clinical settings, such as potential therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

miR‑141 impairs mitochondrial function in cardiomyocytes subjected to hypoxia/reoxygenation by targeting Sirt1 and MFN2

Mitochondrial oxidative stress and dysfunction are major pathogenic features of cardiac injury induced by ischemia/reperfusion (I/R). MicroRNA-141 (miR-141) has been implicated in the mitochondrial dysfunction in cell-based models of oxidant stress. Thus, the main aim of the present study was to systematically assess the role of miR-141 in cardiomyocyte injury induced by simulated I/R. The challenge of HL-1 cardiomyocytes with hypoxia/reoxygenation (H/R) decreased cell viability, which was also associated with an increase in miR-141 expression. The H/R-induced cell injury was mitigated by a miR-141 inhibitor and exacerbated by a miR-141 mimic. Furthermore, H/R induced mitochondrial superoxide production, dysfunction (decreased oxygen utilization and membrane depolarization), as well as ultrastructural damage. These mitochondrial effects were mitigated by a miR-141 inhibitor and intensified by a miR-141 mimic. Luciferase reporter assay, reverse transcription-quantitative PCR, and western blot analyses identified sirtuin-1 (Sirt1) and mitofusin-2 (MFN2) as targets of miR-141. The silencing of Sirt1 reduced the MFN2 cardiomyocyte levels and reversed the alleviating effects of miR-141 inhibitor on mitochondrial function during H/R. Collectively, these findings suggest that miR-141 functions as a causative agent in cardiomyocyte injury induced by I/R, primarily by interfering with two mitochondrial regulatory proteins, Sirt1 and MFN2.

MicroRNA expression profiles in familial hypertrophic cardiomyopathy with myosin-binding protein C3 (MYBPC3) gene mutations

Familial hypertrophic cardiomyopathy (FHCM) is an autosomal dominant inherited disease caused by mutations in genes encoding cardiac sarcomere proteins. MicroRNAs (miRNAs) play an important role in the pathogenesis of FHCM. In the present study, we aimed to determine the miRNA profile in FHCM patients with myosin-binding protein C3 (MYBPC3) gene mutations. We recruited three FHCM patients and age- and sex-matched controls. The three probands all had hypertrophic obstructive cardiomyopathy with severe myocardial hypertrophy, and two of the three had a history of sudden cardiac death, representing a “malignant” phenotype. We then compared the miRNA expression profiles of three FHCM patients carrying MYBPC3 gene mutations with those of the normal control group using miRNA sequencing technology. Differentially expressed miRNAs were verified using real-time polymerase chain reaction (qPCR). Target genes and signaling pathways of the identified differentially expressed miRNAs were predicted using bioinformatics analysis. A total of 33 significantly differentially expressed miRNAs were detected in the peripheral blood of the three probands, of which 28 were upregulated, including miR-208b-3p, and 5 were downregulated. Real-time PCR confirmed the upregulated expression of miR-208b-3p in FHCM patients (P < 0.05). Bioinformatics analysis showed that miR-208b-3p was mainly enriched in 79 target genes including UBE2V2, MED13, YBX1, CNKSR2, GATA4, andSOX5/6, et al. Gene ontology (GO) analysis of target genes showed that miR-208b was mainly involved in the processes of negative regulation of transcription from RNA polymerase II promoter, and regulation of transcription, DNA templated. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the target genes regulated by miR-208b-3p were mainly involved in the Wnt signaling pathway. These findings suggest that FHCM patients with MYBPC3 gene mutations have a specific miRNA expression profile, and that miR-208b-3p is significantly upregulated in cardiac hypertrophy. Our results also indicate that miRNA-208b-3p activates the Wnt signaling pathway through its target gene to promote cardiac hypertrophy.

Neutrophil-like cell membrane-coated siRNA of lncRNA AABR07017145.1 therapy for cardiac hypertrophy via inhibiting ferroptosis of CMECs

Cardiac microvascular dysfunction is associated with cardiac hypertrophy and can eventually lead to heart failure. Dysregulation of long non-coding RNAs (lncRNAs) has recently been recognized as one of the key mechanisms involved in cardiac hypertrophy. However, the potential roles and underlying mechanisms of lncRNAs in cardiac microvascular dysfunction have not been explicitly delineated. Our results confirmed that cardiac microvascular dysfunction was related to cardiac hypertrophy and ferroptosis of cardiac microvascular endothelial cells (CMECs) occurred during cardiac hypertrophy. Using a combination of in vivo and in vitro studies, we identified a lncRNA AABR07017145.1, named as lncRNA AAB for short, and revealed that lncRNA AAB was upregulated in the hearts of cardiac hypertrophy rats as well as in the Ang II-induced CMECs. Importantly, we found that lncRNA AAB sponged and sequestered miR-30b-5p to induce the imbalance of MMP9/TIMP1, which enhanced the activation of transferrin receptor 1 (TFR-1) and then eventually led to the ferroptosis of CMECs. Moreover, we have developed a delivery system based on neutrophil membrane (NM)-camouflaged mesoporous silica nanocomplex (MSN) for inhibition of cardiac hypertrophy, indicating the potential role of silenced lncRNA AAB (si-AAB) and overexpressed miR-30b-5p as the novel therapy for cardiac hypertrophy.

LncRNA TINCR improves cardiac hypertrophy by regulating the miR-211-3p-VEGFB-SDF-1α-CXCR4 pathway

Cardiac hypertrophy is a common cardiovascular disease that is found worldwide and is characterized by heart enlargement, eventually resulting in heart failure. Exploring the regulatory mechanism of cardiac hypertrophy is beneficial for understanding its pathogenesis and treatment. In our study, we have showed TINCR was downregulated and miR-211-3p was upregulated in TAC- or Ang II-induced models of cardiac hypertrophy. Dual luciferase and RIP assays revealed that TINCR served as a competitive endogenous RNA (ceRNA) for miR-211-3p. Then, we observed that knockdown of miR-211-3p alleviated TAC- or Ang II-induced cardiac hypertrophy both in vivo and in vitro. Mechanistically, we demonstrated that miR-211-3p directly targeted VEGFB and thus regulated the expression of SDF-1α and CXCR4. Rescue assays further confirmed that TINCR suppressed the progression of cardiac hypertrophy by competitively binding to miR-211-3p, thereby enhancing the expression of VEGFB and activating the VEGFB-SDF-1α- CXCR4 signal. Furthermore, overexpression of TINCR suppressed TAC-induced cardiac hypertrophy in vivo by targeting miR-211-3p-VEGFB-SDF-1α- CXCR4 signalling. In conclusion, our research suggests that LncRNA TINCR improves cardiac hypertrophy by targeting miR-211-3p, thus relieving its suppressive effects on the VEGFB-SDF-1α-CXCR4 signalling axis. TINCR and miR-211-3p might act as therapeutic targets for the treatment of cardiac hypertrophy.

Therapeutic Strategies Targeting Mitochondrial Calcium Signaling: A New Hope for Neurological Diseases?

Calcium (Ca²⁺) is a versatile secondary messenger involved in the regulation of a plethora of different signaling pathways for cell maintenance. Specifically, intracellular Ca²⁺ homeostasis is mainly regulated by the endoplasmic reticulum and the mitochondria, whose Ca²⁺ exchange is mediated by appositions, termed endoplasmic reticulum-mitochondria-associated membranes (MAMs), formed by proteins resident in both compartments. These tethers are essential to manage the mitochondrial Ca²⁺ influx that regulates the mitochondrial function of bioenergetics, mitochondrial dynamics, cell death, and oxidative stress. However, alterations of these pathways lead to the development of multiple human diseases, including neurological disorders, such as amyotrophic lateral sclerosis, Friedreich's ataxia, and Charcot-Marie-Tooth. A common hallmark in these disorders is mitochondrial dysfunction, associated with abnormal mitochondrial Ca²⁺ handling that contributes to neurodegeneration. In this work, we highlight the importance of Ca²⁺ signaling in mitochondria and how the mechanism of communication in MAMs is pivotal for mitochondrial maintenance and cell homeostasis. Lately, we outstand potential targets located in MAMs by addressing different therapeutic strategies focused on restoring mitochondrial Ca²⁺ uptake as an emergent approach for neurological diseases.

Role of GTPase-Dependent Mitochondrial Dynamins in Heart Diseases

Heart function maintenance requires a large amount of energy, which is supplied by the mitochondria. In addition to providing energy to cardiomyocytes, mitochondria also play an important role in maintaining cell function and homeostasis. Although adult cardiomyocyte mitochondria appear as independent, low-static organelles, morphological changes have been observed in cardiomyocyte mitochondria under stress or pathological conditions. Indeed, cardiac mitochondrial fission and fusion are involved in the occurrence and development of heart diseases. As mitochondrial fission and fusion are primarily regulated by mitochondrial dynamins in a GTPase-dependent manner, GTPase-dependent mitochondrial fusion (MFN1, MFN2, and OPA1) and fission (DRP1) proteins, which are abundant in the adult heart, can also be regulated in heart diseases. In fact, these dynamic proteins have been shown to play important roles in specific diseases, including ischemia-reperfusion injury, heart failure, and metabolic cardiomyopathy. This article reviews the role of GTPase-dependent mitochondrial fusion and fission protein-mediated mitochondrial dynamics in the occurrence and development of heart diseases.

Therapeutic potential and recent advances on targeting mitochondrial dynamics in cardiac hypertrophy: A concise review

Pathological cardiac hypertrophy begins as an adaptive response to increased workload; however, sustained hemodynamic stress will lead it to maladaptation and eventually cardiac failure. Mitochondria, being the powerhouse of the cells, can regulate cardiac hypertrophy in both adaptive and maladaptive phases; they are dynamic organelles that can adjust their number, size, and shape through a process called mitochondrial dynamics. Recently, several studies indicate that promoting mitochondrial fusion along with preventing mitochondrial fission could improve cardiac function during cardiac hypertrophy and avert its progression toward heart failure. However, some studies also indicate that either hyperfusion or hypo-fission could induce apoptosis and cardiac dysfunction. In this review, we summarize the recent knowledge regarding the effects of mitochondrial dynamics on the development and progression of cardiac hypertrophy with particular emphasis on the regulatory role of mitochondrial dynamics proteins through the genetic, epigenetic, and post-translational mechanisms, followed by discussing the novel therapeutic strategies targeting mitochondrial dynamic pathways.

Regulation of Mitochondrial Function by Noncoding RNAs in Heart Failure and Its Application in Diagnosis and Treatment

ABSTRACT

Heart failure (HF) is the terminal stage of multiple cardiovascular diseases. However, the pathogenesis of HF remains unclear and prompt; appropriate diagnosis and treatment of HF are crucial. Cardiomyocytes isolated from HF subjects frequently present mitochondrial impairment and dysfunction. Many studies have suggested that the regulation by noncoding RNAs (ncRNAs) of mitochondria can affect the occurrence and progression of HF. The regulation by ncRNAs of myocardial mitochondria during HF and the recent applications of ncRNAs in the diagnosis and treatment of HF are summarized in this review that is intended to gain keen insights into the mechanisms of HF and more effective treatments.

Krüppel-like factor 15 reduces ischemia-induced apoptosis involving regulation of p38/MAPK signaling

Background Cardiomyocyte apoptosis is a characteristic of a variety of cardiac diseases including myocardial infarction (MI). Krüppel-like factor 15 (KLF15) is a transcription factor of Krüppel family that plays an important part in cardiovascular diseases. However, the function and the underlying mechanism of KLF15 in MI remain unknown. Methods and Results The expression of KLF15 was downregulated both in ischemic myocardium of MI mice model and hypoxia-treated neonatal rat ventricular myocytes (NRVCs). KLF15 overexpression mediated by adeno-associated virus significantly abrogated the ischemia-induced cardiac dysfunction, increased the survival rate and reduced infarct size after MI. Meanwhile, KLF15 overexpression dramatically reduced the myocardial apoptosis, regulated apoptosis-related genes such as Bcl2 and Bax, diminished the activities of caspase-9/3 and inactivated p38/MAPK signaling in the border zone. Similar results were observed in NRVCs exposed to hypoxia. Conclusions We demonstrated for the first time that KLF15 overexpression could reduce cardiomyocyte apoptosis and improve cardiac dysfunction in MI mice at least partially by inhibiting p38/MAPK signaling pathway.

Novel Insights and Current Evidence for Mechanisms of Atherosclerosis: Mitochondrial Dynamics as a Potential Therapeutic Target

Cardiovascular disease (CVD) is the main cause of death worldwide. Atherosclerosis is the underlying pathological basis of CVD. Mitochondrial homeostasis is maintained through the dynamic processes of fusion and fission. Mitochondria are involved in many cellular processes, such as steroid biosynthesis, calcium homeostasis, immune cell activation, redox signaling, apoptosis, and inflammation, among others. Under stress conditions, mitochondrial dynamics, mitochondrial cristae remodeling, and mitochondrial ROS (mitoROS) production increase, mitochondrial membrane potential (MMP) decreases, calcium homeostasis is imbalanced, and mitochondrial permeability transition pore open (mPTP) and release of mitochondrial DNA (mtDNA) are activated. mtDNA recognized by TLR9 can lead to NF-κB pathway activation and pro-inflammatory factor expression. At the same time, TLR9 can also activate NLRP3 inflammasomes and release interleukin, an event that eventually leads to tissue damage and inflammatory responses. In addition, mitochondrial dysfunction may amplify the activation of NLRP3 through the production of mitochondrial ROS, which together aggravate accumulating mitochondrial damage. In addition, mtDNA defects or gene mutation can lead to mitochondrial oxidative stress. Finally, obesity, diabetes, hypertension and aging are risk factors for the progression of CVD, which are closely related to mitochondrial dynamics. Mitochondrial dynamics may represent a new target in the treatment of atherosclerosis. Antioxidants, mitochondrial inhibitors, and various new therapies to correct mitochondrial dysfunction represent a few directions for future research on therapeutic intervention and amelioration of atherosclerosis.

MicroRNAs Regulating Mitochondrial Function in Cardiac Diseases

Mitochondria are the key organelles that supply cellular energy. As the most active organ in the body, the energy required to maintain the mechanical function of the heart requires a high quantity of high-quality mitochondria in cardiomyocytes. MicroRNAs (miRNAs) are single-stranded noncoding RNAs, approximately 22 nt in length, which play key roles in mediating post-transcriptional gene silencing. Numerous studies have confirmed that miRNAs can participate in the occurrence and development of cardiac diseases by regulating mitochondrial function-related genes and signaling pathways. Therefore, elucidating the crosstalk that occurs between miRNAs and mitochondria is important for the prevention and treatment of cardiac diseases. In this review, we discuss the biogenesis of miRNAs, the miRNA-mediated regulation of major genes involved in the maintenance of mitochondrial function, and the effects of miRNAs on mitochondrial function in cardiac diseases in order to provide a theoretical basis for the clinical prevention and treatment of cardiac disease and the development of new drugs.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Quercetin Improves Cardiomyocyte Vulnerability to Hypoxia by Regulating SIRT1/TMBIM6-Related Mitophagy and Endoplasmic Reticulum Stress

Cardiomyocyte apoptosis is an important pathological mechanism underlying cardiovascular diseases and is commonly caused by hypoxia. Moreover, hypoxic injury occurs not only in common cardiovascular diseases but also following various treatments of heart-related conditions. One of the major mechanisms underlying hypoxic injury is oxidative stress. Quercetin has been shown to exert antioxidant stress and vascular protective effects, making it a promising candidate for treating cardiovascular diseases. Therefore, we examined the protective effect of quercetin on human cardiomyocytes subjected to hypoxia-induced oxidative stress damage and its underlying mechanism. Human cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) in vitro with or without quercetin pretreatment; thereafter, flow cytometry, Cell Counting Kit-8 assay, laser scanning confocal microscopy, quantitative PCR, western blotting, and enzyme-linked immunosorbent assay were performed to analyze the effects of quercetin on cardiomyocytes. We found that H/R induced reactive oxygen species overproduction and endoplasmic reticulum stress, as well as inhibited the function of the mitochondria/endoplasmic reticulum and mitophagy, eventually leading to apoptosis and decreasing the viability of human cardiomyocytes. Quercetin pretreatment inhibited H/R-mediated overproduction of reactive oxygen species and damage caused by oxidative stress, increased mitophagy, regulated mRNA and protein expression of transmembrane BAX inhibitor-1 motif-containing 6 (TMBIM6), regulated endoplasmic reticulum stress, and improved the vulnerability of human cardiomyocytes to H/R. Furthermore, transfection with short interfering RNA against silent information regulator protein 1 (SIRT1) counteracted the protective effects of quercetin on cardiomyocytes. Thus, quercetin was predicted to regulate mitophagy and endoplasmic reticulum stress through SIRT1/TMBIM6 and inhibit H/R-induced oxidative stress damage. These findings may be useful for developing treatments for hypoxic injury-induced cardiovascular diseases and further highlight the potential of quercetin for regulating mitochondrial quality control and endoplasmic reticulum function.

Puerarin Attenuates LPS-Induced Inflammatory Responses and Oxidative Stress Injury in Human Umbilical Vein Endothelial Cells through Mitochondrial Quality Control

Atherosclerosis is closely associated with the inflammatory reaction of vascular endothelial cells. Puerarin (Pue), the main active component isolated from the rhizome of Pueraria lobata, is an isoflavone compound with potent antioxidant properties. Although Pue exhibits promising antiatherosclerotic pharmacological effects, only a few studies have reported its protective effect on endothelial cells. This study found that Pue could partly regulate mitochondrial function in human umbilical vein endothelial cells (HUVECs) and reduce or inhibit lipopolysaccharide-induced inflammatory reactions and oxidative stress injury in HUVECs, likely via mitochondrial quality control. Furthermore, the protective effect of Pue on HUVECs was closely related to the SIRT-1 signaling pathway. Pue increased autophagy and mitochondrial antioxidant potential via increased SIRT-1 expression, reducing excessive production of ROS and inhibiting the expression of inflammatory factors and oxidative stress injury. Therefore, Pue may improve mitochondrial respiratory function and energy metabolism, increasing the vulnerability of HUVECs to an inflammatory state.

Novel Insights into the Molecular Features and Regulatory Mechanisms of Mitochondrial Dynamic Disorder in the Pathogenesis of Cardiovascular Disease

Mitochondria maintain mitochondrial homeostasis through continuous fusion and fission, that is, mitochondrial dynamics, which is precisely mediated by mitochondrial fission and fusion proteins, including dynamin-related protein 1 (Drp1), mitofusin 1 and 2 (Mfn1/2), and optic atrophy 1 (OPA1). When the mitochondrial fission and fusion of cardiomyocytes are out of balance, they will cause their own morphology and function disorders, which damage the structure and function of the heart, are involved in the occurrence and progression of cardiovascular disease such as ischemia-reperfusion injury (IRI), septic cardiomyopathy, and diabetic cardiomyopathy. In this paper, we focus on the latest findings regarding the molecular features and regulatory mechanisms of mitochondrial dynamic disorder in cardiovascular pathologies. Finally, we will address how these findings can be applied to improve the treatment of cardiovascular disease.

Adeno-associated virus-mediated delivery of anti-miR-199a tough decoys attenuates cardiac hypertrophy by targeting PGC-1alpha

MicroRNAs (miRNAs) are important regulators in the process of cardiac hypertrophy and heart failure. Previous studies have shown that miR-199a is upregulated in pressure-overload cardiac hypertrophy and that inhibition of miR-199a attenuates cardiac hypertrophy in vitro. However, the therapeutic role of anti-miR-199a treatment in the cardiac hypertrophy in vivo model is less known. Here, we show an efficient and useful method to treat mouse cardiac hypertrophy and restore cardiac function through injection of adeno-associated virus (AAV)-mediated anti-miR-199a tough decoys (TuDs). RNA-seq transcriptome analysis indicated that genes related to cytoplasmic translation and mitochondrial respiratory chain complex assembly were upregulated in anti-miR-199a-treated recovered hearts. We further validated that PGC-1α is the direct target of miR-199a involved in the therapeutic effect and the regulation of the PGC-1α/ERRα axis and that the downstream pathway of mitochondrial fatty acid oxidation and oxidative phosphorylation constitute the underlying mechanism of the restored mitochondrial structure and function in our anti-miR-199a-treated mice. Our study highlights the important regulatory role of miR-199a in cardiac hypertrophy and the value of the AAV-mediated miRNA delivery system.