Programmed Release METTL3-14 Inhibitor Microneedle Protects Myocardial Function by Reducing Drp1 m6A Modification-Mediated Mitochondrial Fission

Nanomedicines for cardiovascular diseases: Lessons learned and pathways forward

Cardiovascular diseases (CVDs) are vital causes of global mortality. Apart from lifestyle intervention like exercise for high-risk groups or patients at early period, various medical interventions such as percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery have been clinically used to reduce progression and prevalence of CVDs. However, invasive surgery risk and severe complications still contribute to ventricular remodeling, even heart failure. Innovations in nanomedicines have fueled impressive medical advances, representing a CVD therapeutic alternative. Currently, clinical translation of nanomedicines from bench to bedside continues to suffer unpredictable biosafety and orchestrated behavior mechanism, which, if appropriately addressed, might pave the way for their clinical implementation in the future. While state-of-the-art advances in CVDs nanomedicines are widely summarized in this review, the focus lies on urgent preclinical concerns and is transitioned to the ongoing clinical trials including stem cells-based, extracellular vesicles (EV)-based, gene, and Chimeric Antigen Receptor T (CAR T) cell therapy whose clinically applicable potential in CVD therapy will hopefully provide first answers. Overall, this review aims to provide a concise but comprehensive understanding of perspectives and challenges of CVDs nanomedicines, especially from a clinical perspective.

Alkbh5 promotes Ythdf1 expression through demethylation thereby facilitating Fth1 translation to inhibit ferroptosis of myocardial infarction

BACKGROUND

Myocardial infarction (MI) is a leading cause of global mortality. Ferroptosis, an iron-dependent form of programmed cell death, has recently emerged as a critical player in cardiovascular diseases. N6-methyladenosine (m6A), the most prevalent RNA methylation modification in eukaryotic cells, has been implicated in various pathological processes; however, its regulatory role in MI through ferroptosis remains poorly understood. This study aimed to elucidate the mechanism by which m6A methylation mediates MI via ferroptosis.

METHODS

A hypoxia/reoxygenation (H/R) model was established using H9C2 cells to simulate myocardial injury. RNA methylation levels were quantified via dot blot assay. Ferroptosis was evaluated by measuring lactate dehydrogenase (LDH) release, Fe2+ levels, glutathione (GSH), lipid reactive oxygen species (ROS), malondialdehyde (MDA), and apoptosis. The underlying molecular mechanisms were investigated using western blotting, quantitative real-time PCR (qPCR), methylated RNA immunoprecipitation (MeRIP), and RIP. Findings were further validated in a myocardial ischemia/reperfusion injury (MIRI) rat model.

RESULTS

The results revealed that m6A levels were significantly elevated in the H/R cell model, accompanied by reduced expression of Alkbh5 mRNA. Moreover, Alkbh5 overexpression inhibited ferroptosis increased in the H/R model. Mechanistically, Alkbh5 overexpression decreased m6A levels of Ythdf1 and H9C2 cells while promoting Fth1 translation by enhancing Ythdf1 mRNA expression. Knockdown of Ythdf1 restored ferroptosis in the H/R model, counteracting the effects of Alkbh5 overexpression. Furthermore, Alkbh5 overexpression alleviated myocardial injury in the MIRI rat model, upregulated Ythdf1 mRNA expression, and increased Fth1 protein levels.

CONCLUSION

This study demonstrates that Alkbh5 ameliorates MI by inhibiting ferroptosis through m6A demethylation of Fth1. These findings provide novel insights into the molecular mechanisms underlying MI and highlight potential therapeutic targets for MI treatment.

A comprehensive review of m6 A methylation in coronary heart disease

The morbidity and mortality rates of coronary heart disease (CHD) are high worldwide. The primary pathological changes in CHD involve stenosis and ischemia caused by coronary atherosclerosis (AS). Extensive research on the pathogenesis of AS has revealed chronic immunoinflammatory processes and cell proliferation in all layers of coronary vessels, including endothelial cells (ECs), vascular smooth muscle cells, and macrophages. m6 A methylation is a common posttranscriptional modification of RNA that is coordinated by a variety of regulators (writers, readers, erasers) to maintain the functional stability of modified mRNAs and ncRNAs. In recent years, there has been increasing focus on the involvement of m6 A methylation in the incidence and progression of CHD, which starts with atherosclerotic plaque formation, leads to myocardial ischemia, and ultimately results in the occurrence of myocardial infarction (MI). m6 A regulators modulate relevant signaling pathways to participate in the inflammatory response, programmed death of cardiomyocytes, and fibrosis. Therefore, diagnostic models based on m6 A profiling are helpful for the early detection of CHD, and m6 A methylation shows promise as a sensitive target for new drugs to treat CHD in the future.

Role of METTL14 in cardiomyocyte pyroptosis in mice with heart failure by regulating miR-221-3p RNA methylation

Heart failure (HF) is a serious and chronic condition. Methyltransferase like 14 (METTL14) is an important component of the m6A methyltransferase complex. This study seeks to explore the mechanism by which METTL14 regulates cardiomyocyte pyroptosis in mice with HF, providing a novel target for HF treatment. Both mouse and cell models were treated with doxorubicin (DOX) to induce HF, followed by measurement of heart function parameters and myocardial damage marker. Next, in cell models, the expression of METTL14, miR-221-3p, pri-miR-221, LncRNA FTX, SESN2, and pyroptosis-related factors was detected. The m6A levels of pri-miR-221, the bindings of miR-221-3p to LncRNA FTX and FUS to LncRNA FTX or SESN2, and the interaction between miR-221-3p and LncRNA FTX were detected. We found that METTL14 was overexpressed in mouse and cell models. METTL14-mediated m6A modification upregulated miR-221-3p expression and inhibited LncRNA FTX expression, reducing the binding of LncRNA FTX to FUS, ultimately inhibiting SESN2 expression. Knockout of METTL14 improved heart function, as evidenced by increased EF and FS, decreased LVIDd and LVIDs, and reduced CK, CK-MB, and LDH, and reduced cardiomyocyte pyroptosis (the levels of cleaved Caspase-1, GSDMD-N, NLRP3, IL-18, and IL-1β were decreased). miR-221-3p overexpression or SESN2 downregulation partially reversed the protective effects of METTL14 downregulation on cardiomyocyte pyroptosis and HF. In conclusion, METTL14-mediated m6A modification exacerbates cardiomyocyte pyroptosis and HF through the miR-221-3p/LncRNA FTX/SESN2 axis, highlighting a potential therapeutic target for HF.

The Emerging Role of m6A and Programmed Cell Death in Cardiovascular Diseases

N6-methyladenosine (m6A) is the most prevalent internal chemical modification in eukaryotic messenger RNA (mRNA), significantly impacting its lifecycle through dynamic and reversible processes involving methyltransferase, demethylase, and binding proteins. These processes regulate mRNA stability, splicing, nuclear export, translation, and degradation. Programmed cell death (PCD), a tightly controlled process encompassing apoptosis, pyroptosis, ferroptosis, autophagy, and necroptosis, plays a crucial role in maintaining cellular homeostasis, tissue development, and function. Recently, m6A modification has emerged as a significant research area due to its role in regulating PCD and its implications in cardiovascular diseases (CVDs). In this review, we delve into the intricate relationship between various PCD types and m6A modification, emphasizing their pivotal roles in the initiation and progression of CVDs such as myocardial ischemia-reperfusion (I/R), atherosclerosis (AS), pulmonary hypertension (PH), cardiomyopathy, doxorubicin (Dox)-induced cardiotoxicity (DIC), heart failure (HF), and myocardial infarction (MI). Our findings underscore the potential of elucidating the roles of m6A and PCD in CVD to pave new pathways for prevention and treatment strategies.

FTO suppresses cardiac fibrosis after myocardial infarction via m6A-mediated epigenetic modification of EPRS

BACKGROUND

Cardiac fibrosis is common in myocardial infarction (MI), leading to progressive cardiac dysfunction. Studies suggested that the abnormal N6-methyladenosine (m6A) modification induced by fat mass and obesity protein (FTO) is vital in MI. However, the effects of FTO on post-infarction cardiac fibrosis have not been detected.

METHODS

Western blot and quantitative real-time PCR were performed to detect the expression of FTO in the fibrotic tissue of rats. The functions of FTO on collagen biosynthesis were analyzed in vitro and in vivo. The underlying targets of FTO were selected through RNA-seq with m6A-seq. The following dual luciferase reporter assay and RNA stability assay were conducted to investigate the mechanisms of FTO-mediated m6A regulation.

RESULTS

The expression of FTO was decreased in the fibrotic tissue of post-infarction rats. The HIF-1 signal pathway was enriched after MI. HIF-1α could bind to the promoter of FTO and inhibit its expression. Functionally, FTO inhibited collagen synthesis after MI in vitro and in vivo. Mechanistically, EPRS was selected as the underlying target of FTO-induced m6A regulation. IGF2BP3 recognized and bound to the m6A sites of EPRS mRNA, which improved its stability. EPRS was required for cardiac fibrosis induced by FTO silencing.

CONCLUSIONS

FTO, identified as a cardioprotective factor, suppressed collagen synthesis in post-infarction cardiac fibrosis via m6A modification, which provided a new therapeutic strategy for cardiac fibrosis.

m6A control programmed cell death in cardiac fibrosis

N6-methyladenosine (m6A) modification is closely related to cardiac fibrosis. As the most common and abundant form of mRNA modification in eukaryotes, m6A is deposited by methylases ("writers"), recognized and effected by RNA-binding proteins ("readers"), and removed by demethylases ("erasers"), achieving highly dynamic reversibility. m6A modification is involved in regulating the entire biological process of target RNA, including transcription, processing and splicing, export from the nucleus to the cytoplasm, and enhancement or reduction of stability and translation. Programmed cell death (PCD) comprises many forms and pathways, with apoptosis and autophagy being the most common. Other forms include pyroptosis, ferroptosis, necroptosis, mitochondrial permeability transition (MPT)-dependent necrosis, and parthanatos. In recent years, increasing evidence suggests that m6A modification can mediate PCD, affecting cardiac fibrosis. Since the correlation between some PCD types and m6A modification is not yet clear, this article mainly introduces the relationship between four common PCD types (apoptosis, autophagy, pyroptosis, and ferroptosis) and m6A modification, as well as their role and influence in cardiac fibrosis.

Unravelling the impact of RNA methylation genetic and epigenetic machinery in the treatment of cardiomyopathy

Cardiomyopathy (CM) represents a heterogeneous group of diseases primarily affecting cardiac structure and function, with genetic and epigenetic dysregulation playing a pivotal role in its pathogenesis. Emerging evidence from the burgeoning field of epitranscriptomics has brought to light the significant impact of various RNA modifications, notably N6-methyladenosine (m6A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N1-methyladenosine (m1A), 2'-O-methylation (Nm), and 6,2'-O-dimethyladenosine (m6Am), on cardiomyocyte function and the broader processes of cardiac and vascular remodelling. These modifications have been shown to influence key pathological mechanisms including mitochondrial dysfunction, oxidative stress, cardiomyocyte apoptosis, inflammation, immune response, and myocardial fibrosis. Importantly, aberrations in the RNA methylation machinery have been observed in human CM cases and animal models, highlighting the critical role of RNA methylating enzymes and their potential as therapeutic targets or biomarkers for CM. This review underscores the necessity for a deeper understanding of RNA methylation processes in the context of CM, to illuminate novel therapeutic avenues and diagnostic tools, thereby addressing a significant gap in the current management strategies for this complex disease.

Nanoparticle-Patch System for Localized, Effective, and Sustained miRNA Administration into Infarcted Myocardium to Alleviate Myocardial Ischemia-Reperfusion Injury

Timely blood reperfusion after myocardial infarction (MI) paradoxically triggers ischemia-reperfusion injury (I/RI), which currently has not been conquered by clinical treatments. Among innovative repair strategies for myocardial I/RI, microRNAs (miRNAs) are expected as genetic tools to rescue damaged myocardium. Our previous study identified that miR-30d can provide protection against myocardial apoptosis and fibrosis to alleviate myocardial injury. Although common methods such as liposomes and viral vectors have been used for miRNA transfection, their therapeutic efficiencies have struggled with inefficient in vivo delivery, susceptible inactivation, and immunogenicity. Here, we establish a nanoparticle-patch system for miR-30d delivery in a murine myocardial I/RI model, which contains ZIF-8 nanoparticles and a conductive microneedle patch. Loaded with miR-30d, ZIF-8 nanoparticles leveraging the proton sponge effect enable miR-30d to escape the endocytic pathway, thus avoiding premature degradation in lysosomes. Meanwhile, the conductive microneedle patch offers a distinct advantage by intramyocardial administration for localized, effective, and sustained miR-30d delivery, and it simultaneously releases Au nanoparticles to reconstruct electrical impulses within the infarcted myocardium. Consequently, the nanoparticle-patch system supports the consistent and robust expression of miR-30d in cardiomyocytes. Results from echocardiography and electrocardiogram (ECG) revealed improved heart functions and standard ECG wave patterns in myocardial I/RI mice after implantation of a nanoparticle-patch system for 3 and 6 weeks. In summary, our work incorporated conductive microneedle patch and miR-30d nanodelivery systems to synergistically transcend the limitations of common RNA transfection methods, thus mitigating myocardial I/RI.

Fabrication of nanocrystal forms of ᴅ-cycloserine and their application for transdermal and enteric drug delivery systems

ᴅ-cycloserine (DCS), an FDA-approved medicine for the treatment of tuberculosis, is also a partial agonist at the glycine recognition site of N-methyl-ᴅ-aspartate (NMDA) receptor and has shown significant treatment efficacy for central nervous system (CNS) disorders including depression, schizophrenia, Alzheimer's disease, and post-traumatic stress disorder. The physicochemical properties of DCS, however, limit the options of formulation and medicinal applications of DCS, and warrants further investigation for the development of CNS therapeutics. Nanocrystals play an important role in pharmaceutic design and development. The properties of nanocrystals are remarkably different from their bulk material counterpart, attributed to the large surface-area-to-volume ratio which can improve the bioavailability. In this study, for the first time, DCS, a highly water-soluble compound, has formed nanocrystals and this was confirmed by scanning electronic microscopy and X-ray powder diffraction. Furthermore, DCS nanocrystals were applied to several formulations to test their stability and then to the in vitro Franz diffusion test with reservoir patch formulation as well as in vivo pharmacokinetics study with enteric capsules. We tested these formulations regarding their nanocrystal physical properties, size effect, and dissolution rate, respectively. We found that DCS nanocrystals showed good performance in the Franz diffusion test and rodent pharmacokinetic studies due to the nanoparticle size and faster dissolution as compared with the commercial DCS powder. These DCS nanocrystal formulations could offer a new approach for the development of an advanced drug delivery system for the treatment of CNS disorders.

ROS-Suppression Nanoplatform Combined Activation of STAT3/Bcl-2 Pathway for Preventing Myocardial Infarction in Mice

Myocardial infarction (MI) is the leading cause of death worldwide. The most effective way to treat myocardial infarction is to rescue ischemic cardiomyocytes. After an ischemic event, the overproduction of reactive oxygen species (ROS) is a key driver of myocardial injury. The produced ROS affects mitochondrial function and induces apoptosis in cardiomyocytes. This was accomplished by constructing platelet-membrane-encapsulated ROS-responsive drug-releasing nanoparticles (PMN@NIC-MalNPs) to deliver malonate and niclosamide (NIC). The results revealed that PMN@NIC-MalNPs degraded and released malonate and niclosamide in a high-level ROS microenvironment, effectively reducing the oxidative stress and apoptosis rate. By enhancing basal mitochondrial oxygen consumption rate (OCR), adenosine triphosphate (ATP) production, and spare respiratory capacity (SRC) in vitro, reduced the oxidative stress levels and restored mitochondrial function. In vivo studies revealed that the PMN@NIC-MalNPs improved cardiac dysfunction, inhibited succinate dehydrogenase (SDH) activity, increased ATP production, and reduced the myocardial infarct size in myocardial infarction model mice. Further, transcriptome analysis and Western blot revealed that PMN@NIC-MalNPs prevented apoptosis by activating the expressions of the signal transducer and activator of transcription 3 (STAT3) and Bcl-2, and inhibiting the expression of Bax. Thus, this study provides a novel therapeutic solution for treating myocardial infarction and predicting the viability of an antioxidant and antiapoptotic therapeutic solution in the treatment of myocardial injury.

METTL3-Mediated LINC00475 Alternative Splicing Promotes Glioma Progression by Inducing Mitochondrial Fission

Mitochondrial fission promotes glioma progression. The function and regulation mechanisms of lncRNAs in glioma mitochondrial fission are unclear. The expression of LINC00475 and its correlation with clinical parameters in glioma were analyzed using bioinformatics. Then, in vitro and in vivo assays were performed to explore the function of spliced variant LINC00475 (LINC00475-S) in gliomas. To explore the mechanisms, RNA-seq, MeRIP, RIP, pulldown-IP, dCas9-ALKBH5 editing system, LC/MS, and Western blotting were utilized. LINC00475 was confirmed to be overexpressed and with higher frequencies of AS events in gliomas compared to normal brain tissue and was associated with worse prognosis. In vitro and animal tumor formation experiments demonstrated that the effect of LINC00475-S on proliferation, metastasis, autophagy, and mitochondrial fission of glioma cells was significantly stronger than that of LINC00475. Mechanistically, METTL3 induced the generation of LINC00475-S by splicing LINC00475 through m6A modification and subsequently promotes mitochondrial fission in glioma cells by inhibiting the expression of MIF. Pull-down combined LC/MS and RIP assays identified that the m6A recognition protein HNRNPH1 bound to LINC00475 within GYR and GY domains and promoted LINC00475 splicing. METTL3 facilitated HNRNPH1 binding to LINC00475 in an m6A-dependent manner, thereby inducing generation of LINC00475-S. METTL3 facilitated HNRNPH1-mediated AS of LINC00475, which promoted glioma progression by inducing mitochondrial fission. Targeting AS of LINC00475 and m6A editing could serve as a therapeutic strategy against gliomas.