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

mTORC1 hyperactivation and resultant suppression of macroautophagy contribute to the induction of cardiomyocyte necroptosis by catecholamine surges

Previous studies revealed a controversial role of mechanistic target of rapamycin complex 1 (mTORC1) and mTORC1-regulated macroautophagy in isoproterenol (ISO)-induced cardiac injury. Here we investigated the role of mTORC1 and potential underlying mechanisms in ISO-induced cardiomyocyte necrosis. Two consecutive daily injections of ISO (85 mg/kg, s.c.) or vehicle control (CTL) were administered to C57BL/6J mice with or without rapamycin (RAP, 5 mg/kg, i.p.) pretreatment. Western blot analyses showed that myocardial mTORC1 signaling and the RIPK1-RIPK3-MLKL necroptotic pathway were activated, mRNA expression analyses revealed downregulation of representative TFEB target genes, and Evan's blue dye uptake assays detected increased cardiomyocyte necrosis in ISO-treated mice. However, RAP pretreatment prevented or significantly attenuated the ISO-induced cardiomyocyte necrosis, myocardial inflammation, downregulation of TFEB target genes, and activation of the RIPK1-RIPK3-MLKL pathway. LC3-II flux assays confirmed the impairment of myocardial autophagic flux in the ISO-treated mice. In cultured neonatal rat cardiomyocytes, mTORC1 signaling was also activated by ISO, and inhibition of mTORC1 by RAP attenuated ISO-induced cytotoxicity. These findings suggest that mTORC1 hyperactivation and resultant suppression of macroautophagy play a major role in the induction of cardiomyocyte necroptosis by catecholamine surges, identifying mTORC1 inhibition as a potential strategy to treat heart diseases with catecholamine surges.

Unique miRomics Expression Profiles in Tannerella forsythia-Infected Mandibles during Periodontitis Using Machine Learning

T. forsythia is a subgingival periodontal bacterium constituting the subgingival pathogenic polymicrobial milieu during periodontitis (PD). miRNAs play a pivotal role in maintaining periodontal tissue homeostasis at the transcriptional, post-transcriptional, and epigenetic levels. The aim of this study was to characterize the global microRNAs (miRNA, miR) expression kinetics in 8- and 16-week-old T. forsythia-infected C57BL/6J mouse mandibles and to identify the miRNA bacterial biomarkers of disease process at specific time points. We examined the differential expression (DE) of miRNAs in mouse mandibles (n = 10) using high-throughput NanoString nCounter® miRNA expression panels, which provided significant advantages over specific candidate miRNA or pathway analyses. All the T. forsythia-infected mice at two specific time points showed bacterial colonization (100%) in the gingival surface, along with a significant increase in alveolar bone resorption (ABR) (p < 0.0001). We performed a NanoString analysis of specific miRNA signatures, miRNA target pathways, and gene network analysis. A total of 115 miRNAs were DE in the mandible tissue during 8 and 16 weeks The T. forsythia infection, compared with sham infection, and the majority (99) of DE miRNAs were downregulated. nCounter miRNA expression kinetics identified 67 downregulated miRNAs (e.g., miR-375, miR-200c, miR-200b, miR-34b-5p, miR-141) during an 8-week infection, whereas 16 upregulated miRNAs (e.g., miR-1902, miR-let-7c, miR-146a) and 32 downregulated miRNAs (e.g., miR-2135, miR-720, miR-376c) were identified during a 16-week infection. Two miRNAs, miR-375 and miR-200c, were highly downregulated with >twofold change during an 8-week infection. Six miRNAs in the 8-week infection (miR-200b, miR-141, miR-205, miR-423-3p, miR-141-3p, miR-34a-5p) and two miRNAs in the 16-week infection (miR-27a-3p, miR-15a-5p) that were downregulated have also been reported in the gingival tissue and saliva of periodontitis patients. This preclinical in vivo study identified T. forsythia-specific miRNAs (miR-let-7c, miR-210, miR-146a, miR-423-5p, miR-24, miR-218, miR-26b, miR-23a-3p) and these miRs have also been reported in the gingival tissues and saliva of periodontitis patients. Further, several DE miRNAs that are significantly upregulated (e.g., miR-101b, miR-218, miR-127, miR-24) are also associated with many systemic diseases such as atherosclerosis, Alzheimer's disease, rheumatoid arthritis, osteoarthritis, diabetes, obesity, and several cancers. In addition to DE analysis, we utilized the XGBoost (eXtreme Gradient boost) and Random Forest machine learning (ML) algorithms to assess the impact that the number of miRNA copies has on predicting whether a mouse is infected. XGBoost found that miR-339-5p was most predictive for mice infection at 16 weeks. miR-592-5p was most predictive for mice infection at 8 weeks and also when the 8-week and 16-week results were grouped together. Random Forest predicted miR-592 as most predictive at 8 weeks as well as the combined 8-week and 16-week results, but miR-423-5p was most predictive at 16 weeks. In conclusion, the expression levels of miR-375 and miR-200c family differed significantly during disease process, and these miRNAs establishes a link between T. forsythia and development of periodontitis genesis, offering new insights regarding the pathobiology of this bacterium.

Circular RNA (circ)_0053277 Contributes to Colorectal Cancer Cell Growth, Angiogenesis, Metastasis and Glycolysis

Circular RNAs (circRNAs) have been found to be abnormally expressed in many cancers, including colorectal cancer (CRC). Circ_0053277 has been found to mediate CRC malignant processes and may be a key regulator for CRC progression. Therefore, its role and potential molecular mechanism in CRC process deserve further investigation. Quantitative real-time PCR was used to detect the expression levels of circ_0053277, microRNA-520 h (miR-520 h) and hexokinase 1 (HK1). Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, wound healing assay, transwell assay, and tube formation assay were used to detect CRC cell proliferation, apoptosis, migration, invasion, and angiogenesis. The protein levels of apoptosis-related markers and HK1 were detected by western blot. The relationship between circ_0053277 and miR-520 h or miR-520 h and HK1 in CRC cells was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Cell glycolysis was assessed by detecting glucose uptake and lactate production. The effect of silenced circ_0053277 on CRC tumor growth was evaluated by xenograft model in vivo. Our study found that circ_0053277 expression was elevated in CRC tissues and cells. Moreover, circ_0053277 knockdown suppressed CRC cell proliferation, angiogenesis, migration and invasion, while promoting apoptosis. In terms of mechanism, circ_0053277 sponged miR-520 h, and HK1 was the target of miR-520 h. Meanwhile, miR-520 h inhibitor reversed the inhibitory effect of circ_0053277 silencing on CRC cell progression, and HK1 overexpression also overturned the suppressive effect of miR-520 h on CRC cell growth, angiogenesis and metastasis. Moreover, circ_0053277 knockdown inhibited the glycolysis of CRC cells by regulating miR-520 h/HK1 pathway. In addition, knockdown of circ_0053277 reduced CRC tumor growth in vivo. Circ_0053277 promoted CRC cell growth, angiogenesis, metastasis and glycolysis by miR-520 h/HK1 pathway, confirming that circ_0053277 might be a potential clinical target for CRC treatment.

[The levels of certain circulating microRNAs in hypertrophic cardiomyopathy are associated with echocardiographic parameters]

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease; it is characterized by left ventricular (LV) hypertrophy that cannot be explained by hemodynamic causes. It is believed that sarcomere dysfunction underlies the pathogenesis of this disease, however, only half of patients with the HCM phenotype have mutations in sarcomere-encoding genes. HCM is distinguished by both high genetic and clinical heterogeneity and therefore more studies are seeking to investigate a regulation of gene expression in HCM and how the abnormalities in this process can affect disease phenotype. One of the levels of regulation of gene expression - a post-transcriptional level - is mediated by short non-coding microRNAs that inhibit protein synthesis.

AIM

To identify the correlations between levels of circulating microRNAs, previously shown to be associated with HCM, and clinical parameters of HCM patients.

MATERIALS AND METHODS

Correlation analysis of miR-499a-5p, miR-454 and miR-339-5p plasma levels and clinical parameters of 33 HCM patients, examined from 2019 to 2021, has been performed.

RESULTS

Variants in HCM-associated genes were found in 49% of patients. There were no clinical differences between genotype-positive and genotype-negative patients. MiR-499a-5p level correlated with LV ejection fraction, miR-454 level - with LV diastolic function parameters and miR-339-5p level - with left atrium dimension.

CONCLUSION

Levels of certain circulating microRNAs correlate with echocardiographic parameters in HCM patients.

Noncoding RNAs as Key Regulators for Cardiac Development and Cardiovascular Diseases

Noncoding RNAs (ncRNAs) play fundamental roles in cardiac development and cardiovascular diseases (CVDs), which are a major cause of morbidity and mortality. With advances in RNA sequencing technology, the focus of recent research has transitioned from studies of specific candidates to whole transcriptome analyses. Thanks to these types of studies, new ncRNAs have been identified for their implication in cardiac development and CVDs. In this review, we briefly describe the classification of ncRNAs into microRNAs, long ncRNAs, and circular RNAs. We then discuss their critical roles in cardiac development and CVDs by citing the most up-to-date research articles. More specifically, we summarize the roles of ncRNAs in the formation of the heart tube and cardiac morphogenesis, cardiac mesoderm specification, and embryonic cardiomyocytes and cardiac progenitor cells. We also highlight ncRNAs that have recently emerged as key regulators in CVDs by focusing on six of them. We believe that this review concisely addresses perhaps not all but certainly the major aspects of current progress in ncRNA research in cardiac development and CVDs. Thus, this review would be beneficial for readers to obtain a recent picture of key ncRNAs and their mechanisms of action in cardiac development and CVDs.

Puerarin attenuates isoproterenol‑induced myocardial hypertrophy via inhibition of the Wnt/β‑catenin signaling pathway

Myocardial hypertrophy (MH) is an independent risk factor for cardiovascular disease, which in turn lead to arrhythmia or heart failure. Therefore, attention must be paid to formulation of therapeutic strategies for MH. Puerarin is a key bioactive ingredient isolated from Pueraria genera of plants that is beneficial for the treatment of MH. However, its molecular mechanism of action has not been fully determined. In the present study, 40 µM puerarin was demonstrated to be a safe dose for human AC16 cells using Cell Counting Kit‑8 assay. The protective effects of puerarin against MH were demonstrated in AC16 cells stimulated with isoproterenol (ISO). These effects were characterized by a significant decrease in surface area of cells (assessed using fluorescence staining) and mRNA and protein expression levels of MH‑associated biomarkers, including atrial and brain natriuretic peptide, assessed using reverse transcription‑quantitative PCR and western blotting, as well as β‑myosin heavy chain mRNA expression levels. Mechanistically, western blotting demonstrated that puerarin inhibited activation of the Wnt signaling pathway. Puerarin also significantly decreased phosphorylation of p65; this was mediated via crosstalk between the Wnt and NF‑κB signaling pathways. An inhibitor (Dickkopf‑1) and activator (IM‑12) of the Wnt signaling pathway were used to demonstrate that puerarin‑mediated effects alleviated ISO‑induced MH via the Wnt signaling pathway. The results of the present study demonstrated that puerarin pre‑treatment may be a potential therapeutic strategy for preventing ISO‑induced MH and managing MH in the future.