Se alleviates homocysteine-induced fibrosis in cardiac fibroblasts via downregulation of lncRNA MEG3

Long noncoding RNA MEG3: an active player in fibrosis

Fibrosis, characterized by excess accumulation of extracellular matrix components, disrupts normal tissue structure and causes organ dysfunction. Long noncoding RNAs (lncRNAs) are a subset of RNAs longer than 200 nucleotides that are not converted into proteins. The increasing research indicated that lncRNA maternally expressed gene 3 (MEG3) was dysregulated in the pathologic process of fibrosis in several tissues. LncRNA MEG3 was revealed to regulate the expression of target proteins or serve as a miRNAs sponge to control the development of fibrosis, which was involved in NF-ҡB, PI3K/AKT, JAK2/STAT3, Wnt/β-catenin, ERK/p38, and Hh pathway. Importantly, the interference of MEG3 level ameliorated fibrosis. The present review summarized available studies of lncRNA MEG3 in fibrosis, which is helpful for a deeper understanding of the roles of MEG3 in fibrosis.

The role of long noncoding RNA MEG3 in fibrosis diseases

Fibrosis is a prevalent pathological condition observed in various organs and tissues. It primarily arises from the excessive and abnormal accumulation of the extracellular matrix, resulting in the structural and functional impairment of tissues and organs, which can culminate in death. Many forms of fibrosis, including liver, cardiac, pulmonary, and renal fibrosis, are considered irreversible. Maternally expressed gene 3 (MEG3) is an imprinted RNA gene. Historically, the downregulation of MEG3 has been linked to tumor pathogenesis. However, recent studies indicate an emerging association of MEG3 with fibrotic diseases. In this review, we delve into the current understanding of MEG3's role in fibrosis, aiming to shed light on the molecular mechanisms of fibrosis and the potential of MEG3 as a novel therapeutic target.

Selenomethionine modulates the JAK2 / STAT3 / A20 pathway through oxidative stress to alleviate LPS-induced pyroptosis and inflammation in chicken hearts

Selenium (Se) is involved in many physiopathologic processes in humans and animals and is strongly associated with the development of heart disease. Lipopolysaccharides (LPS) are cell wall components of gram-negative bacteria that are present in large quantities during environmental pollution. To investigate the mechanism of LPS-induced cardiac injury and the efficacy of the therapeutic effect of SeMet on LPS, a chicken model supplemented with selenomethionine (SeMet) and/or LPS treatment, as well as a primary chicken embryo cardiomyocyte model with the combined effect of SeMet / JAK2 inhibitor (INCB018424) and/or LPS were established in this experiment. CCK8 kit, Trypan blue staining, DCFH-DA staining, oxidative stress kits, immunofluorescence staining, LDH kit, real-time fluorescence quantitative PCR, and western blot were used. The results proved that LPS exposure led to ROS explosion, hindered the antioxidant system, promoted the expression of the JAK2 pathway, and increased the expression of genes involved in the pyroptosis pathway, inflammatory factors, and heat shock proteins (HSPs). Upon co-treatment with SeMet and LPS, SeMet reduced LPS-induced pyroptosis and inflammation and restored the expression of HSPs by inhibiting the ROS burst and modulating the antioxidant capacity. Co-treatment with INCB018424 and LPS resulted in inhibited of the JAK2 pathway, attenuating pyroptosis, inflammation, and high expression of HSPs. Thus, LPS induced pyroptosis, inflammation, and changes in HSPs activity by activating of the JAK2 / STAT3 / A20 signaling axis in chicken hearts. Moreover, SeMet has a positive effect on LPS-induced injury. This work further provides a theoretical basis for treating cardiac injury by SeMet.

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

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

Advances in the role of epigenetics in homocysteine-related diseases

Homocysteine has a wide range of biological effects. However, the specific molecular mechanism of its pathogenicity is still unclear. The diseases induced by hyperhomocysteinemia (HHcy) are called homocysteine-related diseases. Clinical treatment of HHcy is mainly through folic acid and B-complex vitamins, which are not effective in reducing the associated end point events. Epigenetics is the alteration of heritable genes caused by DNA methylation, histone modification, noncoding RNAs and chromatin remodeling without altering the DNA sequence. In recent years the role of epigenetics in homocysteine-associated diseases has been gradually discovered. This article summarizes the latest evidence on the role of epigenetics in HHcy, providing new directions for its prevention and treatment.

The multifaceted biology of lncR-Meg3 in cardio-cerebrovascular diseases

Cardio-cerebrovascular disease, related to high mortality and morbidity worldwide, is a type of cardiovascular or cerebrovascular dysfunction involved in various processes. Therefore, it is imperative to conduct additional research into the pathogenesis and new therapeutic targets of cardiovascular and cerebrovascular disorders. Long non-coding RNAs (lncRNAs) have multiple functions and are involved in nearly all cellular biological processes, including translation, transcription, signal transduction, and cell cycle control. LncR-Meg3 is one of them and is becoming increasingly popular. By binding proteins or directly or competitively binding miRNAs, LncR-Meg3 is involved in apoptosis, inflammation, oxidative stress, endoplasmic reticulum stress, epithelial-mesenchymal transition, and other processes. Recent research has shown that LncR-Meg3 is associated with acute myocardial infarction and can be used to diagnose this condition. This article examines the current state of knowledge regarding the expression and regulatory function of LncR-Meg3 in relation to cardiovascular and cerebrovascular diseases. The abnormal expression of LncR-Meg3 can influence neuronal cell death, inflammation, apoptosis, smooth muscle cell proliferation, etc., thereby aggravating or promoting the disease. In addition, we review the bioactive components that target lncR-Meg3 and propose some potential delivery vectors. A comprehensive and in-depth analysis of LncR-Meg3’s role in cardiovascular disease suggests that targeting LncR-Meg3 may be an alternative therapy in the near future, providing new options for slowing the progression of cardiovascular disease.

Fucoidan-Mediated Inhibition of Fibrotic Properties in Oral Submucous Fibrosis via the MEG3/miR-181a/Egr1 Axis

Oral submucous fibrosis (OSF) is a chronic fibrotic remodeling disease that can progress to oral cancer. However, efficient clinical diagnosis and treatment methods for OSF are still lacking. This study investigated the anti-fibrotic effect of fucoidan on oral fibrosis. To evaluate the fibrotic ability (myofibroblast activities), we performed wound-healing, Transwell migration, and collagen contraction assays by using patient-derived normal and fibrotic buccal submucous fibroblasts (BMFs and fBMFs, respectively). RNA-sequencing and dual-luciferase reporter and RNA immunoprecipitation chip assays were performed to identify the clinical significance and molecular mechanism of non-coding RNAs. Fucoidan suppressed the myofibroblast activities and inhibited the MEG3 in fBMFs. MEG3 was overexpressed in the OSF tissue and was positively associated with myofibroblast markers. Knockdown of MEG3 markedly inhibited myofibroblast activities, which were restored by inhibiting miR-181a and overexpressing Egr1. The results from luciferase reporter and RIP assays confirmed that MEG3 functioned as a competing endogenous RNA (ceRNA) and could directly target miR-181a, thereby preventing the miR-181a-mediated translational repression of Egr1. This study demonstrated that MEG3 exerts a profibrotic effect on OSF by targeting miR-181a/Egr1. Therefore, the administration of fucoidan may serve as a potential therapeutic strategy for OSF by targeting the overexpression of MEG3.

Homocysteine promotes cardiac fibrosis by regulating the Akt/FoxO3 pathway

Background

Evaluated plasma homocysteine (Hcy) is an independent risk factor for cardiac fibrosis which is a common feature of cardiovascular disease, although the mechanisms are still unclear. This study aims to explore the mechanism of Hcy-induced cardiac fibrosis.

Methods

The mRNA and protein levels of Forkhead box O3 (FoxO3) and differentiation markers were detected in primary cardiac fibroblasts (CFs) after 300 µM Hcy treatment. Scratch and transwell migration assay were used to determine the effect of Hcy on proliferation and migration in CFs. The protein levels involved in the fibrotic processes in mice fed with high methionine diet (HMD) for 4 or 8 weeks were investigated by western blot. CFs were infected with FoxO3 recombinant adenovirus to explore the potential role of FoxO3 in Hcy-induced cardiac dysfunction.

Results

Hcy treatment significantly promoted the differentiation, proliferation and migration of CFs, while FoxO3 activity were decreased in CFs. In HMD hearts, the protein levels of TIMP1, Fibronectin and α-SMA were increased after 4 or 8 weeks, but the FoxO3 activity was decreased. Moreover, the HMD hearts had a higher level of Bcl2 but lower of Bax and LC3II protein. In addition, FoxO3 overexpression attenuates Hcy-induced dysfunction in CFs.

Conclusions

Hcy promotes myofibroblast activation and resistance to autophagy and apoptosis in CFs, and eventually results in cardiac fibrosis by regulating the Akt/FoxO3 pathway. Thus, FoxO3 is a promising therapeutic target to prevent cardiac remodeling.