Hydrogen sulfide mitigates homocysteine-mediated pathological remodeling by inducing miR-133a in cardiomyocytes

The interplay of hydrogen sulfide and microRNAs in cardiovascular diseases: insights and future perspectives

Hydrogen sulfide (H2S) is recognized as the third gasotransmitter, after nitric oxide (NO) and carbon monoxide (CO). It is known for its cardioprotective properties, including the relaxation of blood vessels, promotion of angiogenesis, regulation of myocardial cell apoptosis, inhibition of vascular smooth muscle cell proliferation, and reduction of inflammation. Additionally, abnormal H2S generation has been linked to the development of cardiovascular diseases (CVD), such as pulmonary hypertension, hypertension, atherosclerosis, vascular calcification, and myocardial injury. MicroRNAs (miRNAs) are non-coding, conserved, and versatile molecules that primarily influence gene expression by repressing translation and have emerged as biomarkers for CVD diagnosis. Studies have demonstrated that H2S can ameliorate cardiac dysfunction by regulating specific miRNAs, and certain miRNAs can also regulate H2S synthesis. The crosstalk between miRNAs and H2S offers a novel perspective for investigating the pathophysiology, prevention, and treatment of CVD. The present analysis outlines the interactions between H2S and miRNAs and their influence on CVD, providing insights into their future potential and advancement.

CircRNA Larp4b/miR-298-5p/Mef2c Regulates Cardiac Hypertrophy Induced by Angiotensin II

Cardiac hypertrophy (CH) is an early marker in the clinical course of heart failure. Circular RNAs (circRNAs) play important roles in human disease. However, the role of circ_Larp4b in myocardial hypertrophy has not been studied. Angiotensin II (Ang II) treated HL-1 cells to induce a CH cell model. Quantitative real-time polymerase chain reaction was used to detect the expression of circ_Larp4b, microRNA-298-5p, and myocyte enhancer factor 2 (Mef2c). Western blot detected the protein level of alpha-actinin-2 (ACTN2), beta-myosin heavy chain (β-MHC), atrial natriuretic peptide (ANP), and Mef2c. The relationship between miR-298-5p and circ_Larp4b or Mef2c was verified by dual-luciferase reporter assay and RNA pull-down assay. Circ_Larp4b and Mef2c were upregulated in HL-1 cells treated with Ang II. Moreover, circ_Larp4b down-regulation regulated the progress of CH induced by Ang II. MiR-298-5p was a target of circ_Larp4b, and Mef2c was a target of miR-298-5p. Overexpressed Mef2c reversed the cell size inhibited by miR-298-5p in Ang II-induced HL-1 cells. Circ_Larp4b regulated CH progress by regulating miR-298-5p/Mef2c axis.

Hydrogen sulfide and epigenetics: Novel insights into the cardiovascular effects of this gasotransmitter

Epigenetics studies the heritable modifications of genome expression that do not affect the nucleotide sequence. Epigenetic modifications can be divided into: DNA methylation, histone modifications, and modulation of genome expression by non-coding RNAs. Alteration of these mechanisms can alter the phenotype, and can lead to disease onset. The endogenous gasotransmitter hydrogen sulfide (H2 S) plays pleiotropic roles in many systems, including the cardiovascular (CV) system, and its mechanism of action mainly includes S-persulfidation of cysteine residues. Recent evidence suggests that many H2 S-mediated biological activities are based on the epigenetic regulation of cellular function, with effects ranging from DNA methylation to modification of histones and regulation of non-coding RNAs. This review describes the role of H2 S-regulating epigenetic mechanisms, providing a panorama of the current literature, and offers a novel scenario for the development of H2 S-releasing 'epidrugs' with a potential clinical use in the prevention and treatment of many CV and non-CV disorders.

Soluble epoxide hydrolase and TRPC3 channels jointly contribute to homocysteine-induced cardiac hypertrophy: Interrelation and regulation by C/EBPβ

OBJECTIVES

Studies in certain cardiac hypertrophy models suggested the individual role of soluble epoxide hydrolase (sEH) and canonical transient receptor potential 3 (TRPC3) channels, however, whether they jointly mediate hypertrophic process remains unexplored. Hyperhomocysteinemia promotes cardiac hypertrophy while the involvement of sEH and TRPC3 channels remains unknown. This study aimed to explore the role of, and interrelation between sEH and TRPC3 channels in homocysteine-induced cardiac hypertrophy.

METHODS

Rats were fed methionine-enriched diet to induce hyperhomocysteinemia. H9c2 cells and neonatal rat cardiomyocytes were incubated with homocysteine. Cardiac hypertrophy was evaluated by echocardiography, histological examination, immunofluorescence imaging, and expressions of hypertrophic markers. Epoxyeicosatrienoic acids (EETs) were determined by ELISA. TRPC3 current was recorded by patch-clamp. Gene promotor activity was measured using dual-luciferase reporter assay.

RESULTS

Inhibition of sEH by 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) reduced ventricular mass, lowered the expression of hypertrophic markers, decreased interstitial collagen deposition, and improved cardiac function in hyperhomocysteinemic rats, associated with restoration of EETs levels in myocardium. TPPU or knockdown of sEH suppressed TRPC3 transcription and translation as well as TRPC3 current that were enhanced by homocysteine. Exogenous 11,12-EET inhibited homocysteine-induced TRPC3 expression and cellular hypertrophy. Silencing C/EBPβ attenuated, while overexpressing C/EBPβ promoted homocysteine-induced hypertrophy and expressions of sEH and TRPC3, resulting respectively from inhibition or activation of sEH and TRPC3 gene promoters.

CONCLUSIONS

sEH and TRPC3 channels jointly contribute to homocysteine-induced cardiac hypertrophy. Homocysteine transcriptionally activates sEH and TRPC3 genes through a common regulatory element C/EBPβ. sEH activation leads to an upregulation of TRPC3 channels via a 11,12-EET-dependent manner.

The Role of Gasotransmitter-Dependent Signaling Mechanisms in Apoptotic Cell Death in Cardiovascular, Rheumatic, Kidney, and Neurodegenerative Diseases and Mental Disorders

Cardiovascular, rheumatic, kidney, and neurodegenerative diseases and mental disorders are a common cause of deterioration in the quality of life up to severe disability and death worldwide. Many pathological conditions, including this group of diseases, are based on increased cell death through apoptosis. It is known that this process is associated with signaling pathways controlled by a group of gaseous signaling molecules called gasotransmitters. They are unique messengers that can control the process of apoptosis at different stages of its implementation. However, their role in the regulation of apoptotic signaling in these pathological conditions is often controversial and not completely clear. This review analyzes the role of nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) in apoptotic cell death in cardiovascular, rheumatic, kidney, and neurodegenerative diseases. The signaling processes involved in apoptosis in schizophrenia, bipolar, depressive, and anxiety disorders are also considered. The role of gasotransmitters in apoptosis in these diseases is largely determined by cell specificity and concentration. NO has the greatest dualism; scales are more prone to apoptosis. At the same time, CO, H₂S, and SO₂ are more involved in cytoprotective processes.

The Functional Interplay between Ethylene, Hydrogen Sulfide, and Sulfur in Plant Heat Stress Tolerance

Plants encounter several abiotic stresses, among which heat stress is gaining paramount attention because of the changing climatic conditions. Severe heat stress conspicuously reduces crop productivity through changes in metabolic processes and in growth and development. Ethylene and hydrogen sulfide (H2S) are signaling molecules involved in defense against heat stress through modulation of biomolecule synthesis, the antioxidant system, and post-translational modifications. Other compounds containing the essential mineral nutrient sulfur (S) also play pivotal roles in these defense mechanisms. As biosynthesis of ethylene and H2S is connected to the S-assimilation pathway, it is logical to consider the existence of a functional interplay between ethylene, H2S, and S in relation to heat stress tolerance. The present review focuses on the crosstalk between ethylene, H2S, and S to highlight their joint involvement in heat stress tolerance.

Endoplasmic reticulum stress mediates homocysteine-induced hypertrophy of cardiac cells through activation of cyclic nucleotide phosphodiesterase 1C

Although the association of elevated homocysteine level with cardiac hypertrophy has been reported, the molecular mechanisms by which homocysteine induces cardiac hypertrophy remain inadequately understood. In this study we aim to uncover the roles of cyclic nucleotide phosphodiesterase 1 (PDE1) and endoplasmic reticulum (ER) stress and their relationship to advance the mechanistic understanding of homocysteine-induced cardiac cell hypertrophy. H9c2 cells and primary neonatal rat cardiomyocytes are exposed to homocysteine with or without ER stress inhibitor TUDCA or PDE1-specific inhibitor Lu AF58027, or transfected with siRNAs targeting PDE1 isoforms prior to homocysteine-exposure. Cell surface area is measured and ultrastructure is examined by transmission electron microscopy. Hypertrophic markers, PDE1 isoforms, and ER stress molecules are detected by q-PCR and western blot analysis. Intracellular cGMP and cAMP are measured by ELISA. The results show that homocysteine causes the enlargement of H9c2 cells, increases the expressions of hypertrophic markers β-MHC and ANP, upregulates PDE1A and PDE1C, promotes the expressions of ER stress molecules, and causes ER dilatation and degranulation. TUDCA and Lu AF58027 downregulate β-MHC and ANP, and alleviate cell enlargement. TUDCA decreases PDE1A and PDE1C levels. Silencing of PDE1C inhibits homocysteine-induced hypertrophy, whereas PDE1A knockdown has minor effect. Both cAMP and cGMP are decreased after homocysteine-exposure, while only cAMP is restored by Lu AF58027 and TUDCA. TUDCA and Lu AF58027 also inhibit cell enlargement, downregulate ANP, β-MHC and PDE1C, and enhance cAMP level in homocysteine-exposed primary cardiomyocytes. ER stress mediates homocysteine-induced hypertrophy of cardiac cells via upregulating PDE1C expression Cyclic nucleotide, especially cAMP, is the downstream mediator of the ER stress-PDE1C signaling axis in homocysteine-induced cell hypertrophy.

miR-195-3p alleviates homocysteine-mediated atherosclerosis by targeting IL-31 through its epigenetics modifications

Atherosclerosis is a serious age-related disease, which has a tremendous impact on health care globally. Macrophage inflammation is crucial for the initiation and progression of atherosclerosis, and microRNAs (miRNAs) recently have emerged as potent modulators of inflammation, while the underlying mechanisms of its involvement in homocysteine (Hcy)-mediated macrophage inflammation of atherosclerosis remain largely unknown. Here, we demonstrated that elevated Hcy inhibits the expression of miR-195-3p, which in turn enhances IL-31 expression and thereby causes the secretion of macrophages pro-inflammatory factors IL-1β, IL-6 and TNF-α and accelerate atherosclerosis. Furthermore, we identified that Hcy can induce DNA hypermethylation and H3K9 deacetylation of miR-195-3p promoter due to the increased the binding of DNMT3a and HDAC11 at its promoter. More importantly, Sp1 interacts with DNMT3a suppressed the binding of HDAC11 at miR-195-3p promoter and promoted its transcription. In summary, our results revealed a novel mechanism that transcriptional and epigenetic regulation of miR-195-3p inhibits macrophage inflammation through targeting IL-31, which provides a candidate diagnostic marker and novel therapeutic target in cardiovascular diseases induced by Hcy.

H2S inhibits atrial fibrillation-induced atrial fibrosis through miR-133a/CTGF axis

AIM

Atrial fibrillation (AF) is a common clinical arrhythmia and can cause a variety of complications. To study the therapeutic effect of H₂S in atrial fibrosis and explore the important role of miR-133a, in vitro experiments in human atrial fibroblasts (HAFs) were conducted.

METHODS

The fibrosis in HAFs was induced by Ang II. The expression levels of miR-133a and CTGF in HAFs were examined by qRT-PCR. The proliferation and migration of HAFs were detected by CCK-8 and cell scratch assays. The protein expressions of CTGF, collagen I, collagen III and α-SMA were detected by western blotting. The dual-luciferase reporter gene was used to detect the interaction between miR-133a and CTGF.

RESULTS

The proliferation and migration of HAFs stimulated by Ang II were enhanced, the expression of miR-133a was reduced, and the levels of CTGF and fibrosis markers (collagen I, collagen III and α-SMA) were increased. Furthermore, H₂S reduced fibrosis, proliferation and migration of HAFs induced by Ang II. Accordingly, overexpression of miR-133a inhibited the proliferation and migration ability on Ang II-induced HAFs, and decreased the protein expressions of related fibrosis markers and CTGF. Meanwhile, miR-133a inhibitor could reverse the inhibition effect of H₂S on proliferation and migration in HAFs by Ang II-induced. By targeting CTGF, miR-133a inhibited the expression of CTGF.

CONCLUSION

H₂S improved myocardial cell fibrosis by significantly increasing the expression of miR-133a, and CTGF might be a potential target for miR-133a to play an important role in myocardial fibrosis.

Abnormal nitration and S-sulfhydration modification of Sp1-CSE-H2S pathway trap the progress of hyperhomocysteinemia into a vicious cycle

Sp1-CSE-H2S pathway plays an important role in homocysteine-metabolism, whose disorder can result in hyperhomocysteinemia. H2S deficiency in hyperhomocysteinemia has been reported, while the underlying mechanism and whether it in turn affects the progress of hyperhomocysteinemia are unclear. This study focused on the post-translational modification of Sp1/CSE and revealed four major findings: (1) Homocysteine-accumulation augmented CSE's nitration, inhibited its bio-activity, thus caused H2S deficiency. (2) H2S deficiency inhibited the S-sulfhydration of Sp1, down-regulated CSE and decreased H2S further, which in turn weakened CSE's own S-sulfhydration. (3) CSE was S-sulfhydrated at Cys84, Cys109, Cys172, Cys229, Cys252, Cys307 and Cys310, among which the S-sulfhydration of Cys172 and Cys310 didn't affect its enzymatic activity, while the S-sulfhydration of Cys84, Cys109, Cys229, Cys252 and Cys307 was necessary for its bio-activity. (4) H2S deficiency trapped homocysteine-metabolism into a vicious cycle, which could be broken by either blocking nitration or restoring S-sulfhydration. This study detected a new mechanism that caused severe hyperhomocysteinemia, thereby provided new therapeutic strategies for hyperhomocysteinemia.

MMP9 inhibition increases autophagic flux in chronic heart failure

Increased matrix metalloprotease 9 (MMP9) after myocardial infarction (MI) exacerbates ischemia-induced chronic heart failure (CHF). Autophagy is cardioprotective during CHF; however, whether increased MMP9 suppresses autophagic activity in CHF is unknown. This study aimed to determine whether increased MMP9 suppressed autophagic flux and MMP9 inhibition increased autophagic flux in the heart of rats with post-MI CHF. Sprague-Dawley rats underwent either sham surgery or coronary artery ligation 6-8 wk before being treated with MMP9 inhibitor for 7 days, followed by cardiac autophagic flux measurement with lysosomal inhibitor bafilomycin A1. Furthermore, autophagic flux was measured in vitro by treating H9c2 cardiomyocytes with two independent pharmacological MMP9 inhibitors, salvianolic acid B (SalB) and MMP9 inhibitor-I, and CRISPR/cas9-mediated MMP9 genetic ablation. CHF rats showed cardiac infarct, significantly increased left ventricular end-diastolic pressure (LVEDP), and increased MMP9 activity and fibrosis in the peri-infarct areas of left ventricular myocardium. Measurement of the autophagic markers LC3B-II and p62 with lysosomal inhibition showed decreased autophagic flux in the peri-infarct myocardium. Treatment with SalB for 7 days in CHF rats decreased MMP9 activity and cardiac fibrosis but increased autophagic flux in the peri-infarct myocardium. As an in vitro corollary study, measurement of autophagic flux in H9c2 cardiomyocytes and fibroblasts showed that pharmacological inhibition or genetic ablation of MMP9 upregulates autophagic flux. These data are consistent with our observations that MMP9 inhibition upregulates autophagic flux in the heart of rats with CHF. In conclusion, the results in this study suggest that the beneficial outcome of MMP9 inhibition in pathological cardiac remodeling is in part mediated by improved autophagic flux.NEW & NOTEWORTHY This study elucidates that the improved cardiac extracellular matrix (ECM) remodeling and cardioprotective effect of matrix metalloprotease 9 (MMP9) inhibition in chronic heart failure (CHF) are via increased autophagic flux. Autophagy is cardioprotective; however, the mechanism of autophagy suppression in CHF is unknown. We for the first time demonstrated here that increased MMP9 suppressed cardiac autophagy and ablation of MMP9 increased cardiac autophagic flux in CHF rats. Restoring the physiological level of autophagy in the failing heart is a challenge, and our study addressed this challenge. The novelty and highlights of this report are as follows: 1) MMP9 regulates cardiomyocyte and fibroblast autophagy, 2) MMP9 inhibition protects CHF after myocardial infarction (MI) via increased cardiac autophagic flux, 3) MMP9 inhibition increased cardiac autophagy via activation of AMP-activated protein kinase (AMPK)α, Beclin-1, Atg7 pathway and suppressed mechanistic target of rapamycin (mTOR) pathway.

Potential role of hydrogen sulfide in diabetes-impaired angiogenesis and ischemic tissue repair

Diabetes is one of the most prevalent metabolic disorders and is estimated to affect 400 million of 4.4% of population worldwide in the next 20 year. In diabetes, risk to develop vascular diseases is two-to four-fold increased. Ischemic tissue injury, such as refractory wounds and critical ischemic limb (CLI) are major ischemic vascular complications in diabetic patients where oxygen supplement is insufficient due to impaired angiogenesis/neovascularization. In spite of intensive studies, the underlying mechanisms of diabetes-impaired ischemic tissue injury remain incompletely understood. Hydrogen sulfide (H₂S) has been considered as a third gasotransmitter regulating angiogenesis under physiological and ischemic conditions. Here, the underlying mechanisms of insufficient H₂S-impaired angiogenesis and ischemic tissue repair in diabetes are discussed. We will primarily focuses on the signaling pathways of H₂S in controlling endothelial function/biology, angiogenesis and ischemic tissue repair in diabetic animal models. We summarized that H₂S plays an important role in maintaining endothelial function/biology and angiogenic property in diabetes. We demonstrated that exogenous H₂S may be a theraputic agent for endothelial dysfunction and impaired ischemic tissue repair in diabetes.

The role of the gasotransmitter hydrogen sulfide in pathological calcification

Calcification is the deposition of minerals, mainly hydroxyapatite, inside the cell or in the extracellular matrix. Physiological calcification is central for many aspects of development including skeletal and tooth growth; conversely, pathological mineralization occurs in soft tissues and is significantly associated with malfunction and impairment of the tissue where it is located. Various mechanisms have been proposed to explain calcification. However, this research area lacks a more integrative, systemic, and global perspective that could explain both physiological and pathological processes. In this review, we propose such an integrated explanation. Hydrogen sulfide (H₂ S) is a newly recognized multifunctional gasotransmitters and tis actions have been studied in different physiological and pathological contexts, but little is known about its potential role on calcification. Interestingly, we found that H₂ S promotes calcification under physiological conditions and has an inhibitory effect on pathological processes. This makes H₂ S a potential therapy for diseases related to pathological calcification. LINKED ARTICLES: This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.

Hydrogen sulfide lowers hyperhomocysteinemia dependent on cystathionine γ lyase S-sulfhydration in ApoE-knockout atherosclerotic mice

BACKGROUND AND PURPOSE

Hydrogen sulfide donors can block the cardiovascular injury of hyperhomocysteinemia. H₂ S also lowers serum homocysteine in rats with mild hyperhomocysteinemia, but the pharmacological mechanism is unknown. The present study investigated the mechanism(s) involved.

EXPERIMENTAL APPROACH

ApoE-knockout mice were fed a Paigen diet and L-methionine in drinking water for 16 weeks to create a mouse model of atherosclerosis with hyperhomocysteinemia. H₂ S donors (NaHS and GYY4137) were administered by intraperitoneal injection. We also assayed the H₂ S produced (by methylene blue assay and mito-HS [H₂ S fluorescence probe]), cystathionine γ lyase (CSE) mRNA and protein expression, and CSE sulfhydration and nitrosylation and its activity.

KEY RESULTS

H₂ S donor treatment significantly lowered atherosclerotic plaque area, macrophage infiltration, and serum homocysteine level in the mouse model of atherosclerosis with co-existing hyperhomocysteinemia. mRNA and protein levels of CSE, a key enzyme catalyzing homocysteine trans-sulfuration, were down-regulated with hyperhomocysteinemia, and CSE catalytic activity was inhibited. All these effects were reversed with H₂ S donor treatment. Hyperhomocysteinemia induced CSE nitrosylation, whereas H₂ S sulfhydrated CSE at the same cysteine residues. Nitrosylated CSE decreased and sulfhydrated CSE increased its catalytic and binding activities towards L-homocysteine. Mutation of C252, C255, C307, and C310 residues in CSE abolished CSE nitrosylation or sulfhydration and prevented its binding to L-homocysteine.

CONCLUSIONS AND IMPLICATIONS

Sulfhydration or nitrosylation of CSE represents a yin/yang regulation of catalysis or binding to L-homocysteine. H₂ S donor treatment enhanced CSE sulfhydration, thus lowering serum L-homocysteine, which contributed in part to the anti-atherosclerosis effects in ApoE-knockout mice with hyperhomocysteinemia.

Exogenous Hydrogen Sulfide Supplement Attenuates Isoproterenol-Induced Myocardial Hypertrophy in a Sirtuin 3-Dependent Manner

Hydrogen sulfide (H₂S) is a gasotransmitter with a variety of cardiovascular protective effects. Sirtuin 3 (SIRT3) is closely related to mitochondrial function and oxidative stress. We found that NaHS increased SIRT3 expression in the preventive effect on isoproterenol- (ISO-) induced myocardial hypertrophy. We further investigated whether exogenous H₂S supplement improved ISO-induced myocardial hypertrophy in a SIRT3-dependent manner. 10-week-old male 129S1/SvImJ (WT) mice and SIRT3 knockout (KO) mice were intraperitoneally injected with NaHS (50 μmol/kg/d) for two weeks and then intraperitoneally injected with ISO (60 mg/kg/d) for another two weeks. In WT mice, NaHS significantly reduced the cardiac index of ISO-induced mice, decreased the cross-sectional area of cardiomyocytes, and inhibited the expressions of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in the myocardium was increased, but the level of malondialdehyde (MDA) was decreased. The fluorescence intensity of dihydroethidium staining for superoxide anion was attenuated. Optic atrophy 1 (OPA1) expression was upregulated, while dynamin-related protein 1 (DRP1) expression was downregulated. ERK, but not P38 and JNK, phosphorylation was downregulated. However, all above protective effects were unavailable in ISO-induced SIRT3 KO mice. Our present study suggested that exogenous H₂S supplement inhibited ISO-induced cardiac hypertrophy depending on SIRT3, which might be associated with antioxidant stress.

Hydrogen Sulfide (H2S)-Releasing Compounds: Therapeutic Potential in Cardiovascular Diseases

Cardiovascular disease is the main cause of death worldwide, but its pathogenesis is not yet clear. Hydrogen sulfide (H₂S) is considered to be the third most important endogenous gasotransmitter in the organism after carbon monoxide and nitric oxide. It can be synthesized in mammalian tissues and can freely cross the cell membrane and exert many biological effects in various systems including cardiovascular system. More and more recent studies have supported the protective effects of endogenous H₂S and exogenous H₂S-releasing compounds (such as NaHS, Na₂S, and GYY4137) in cardiovascular diseases, such as cardiac hypertrophy, heart failure, ischemia/reperfusion injury, and atherosclerosis. Here, we provided an up-to-date overview of the mechanistic actions of H₂S as well as the therapeutic potential of various classes of H₂S donors in treating cardiovascular diseases.

At the heart of programming: the role of micro-RNAs

Epidemiological and experimental observations tend to prove that environment, lifestyle or nutritional challenges influence heart functions together with genetic factors. Furthermore, when occurring during sensitive windows of heart development, these environmental challenges can induce an 'altered programming' of heart development and shape the future heart disease risk. In the etiology of heart diseases driven by environmental challenges, epigenetics has been highlighted as an underlying mechanism, constituting a bridge between environment and heart health. In particular, micro-RNAs which are involved in each step of heart development and functions seem to play a crucial role in the unfavorable programming of heart diseases. This review describes the latest advances in micro-RNA research in heart diseases driven by early exposure to challenges and discusses the use of micro-RNAs as potential targets in the reversal of the pathophysiology.

Expression Profiles of Six Atherosclerosis-Associated microRNAs That Cluster in Patients with Hyperhomocysteinemia: A Clinical Study

The aim of this study is to discuss the hypothesis that expression of plasma atherosclerosis-associated microRNAs (miRNAs) in hyperhomocysteinemia (Hhcy) patients could predict the presence of atherosclerosis from different channels. Six plasma miRNAs (miR-145, miR-155, miR-222, miR-133, miR-217, and miR-30) selected for our study have been confirmed as critical gene regulators involved in atherosclerosis and can be steadily determined in plasma. Expression of the above six plasma circulating miRNAs revealed significant upregulation of two miRNAs (miR-133 and miR-217) and downregulation of three miRNAs (miR-145, miR-155, and miR-222). Six candidate miRNAs showed a significant correlation with homocysteine (Hcy) or lipid parameters. The results of this study indicated that miR-217 was further significantly upregulated in Hhcy + ATH groups than in normal control, Hhcy-, and atherosclerosis-alone (ATH) groups and it showed a significant negative correlation with Hcy and triglycerides. More specifically, miR-217 showed the most specific expression patterns in all patients with atherosclerosis (ATH and Hhcy + ATH groups), which may have been a diagnostic value for Hhcy complicated with atherosclerosis, and predicted the progress of atherosclerosis in Hhcy patients effectively.

MEF2 signaling and human diseases

The members of myocyte Enhancer Factor 2 (MEF2) protein family was previously believed to function in the development of heart and muscle. Recent reports indicate that they are also closely associated with development and progression of many human diseases. Although their role in cancer biology is well established, the molecular mechanisms underlying their action is yet largely unknown. MEF2 family is closely associated with various signaling pathways, including Ca²⁺ signaling, MAP kinase signaling, Wnt signaling, PI3K/Akt signaling, etc. microRNAs also contribute to regulate the activities of MEF2. In this review, we summarize the known molecular mechanism by which MEF2 family contribute to human diseases.

Expression levels of atherosclerosis-associated miR-143 and miR-145 in the plasma of patients with hyperhomocysteinaemia

Background

An elevated level of homocysteine (Hcy) in the blood is designated hyperhomocysteinaemia (Hhcy) and is regarded as a strong risk factor for the development of atherosclerosis (ATH), although the association remains controversial. Considered to be essential gene expression regulators, micro-RNAs (miRNAs) modulate cardiovascular disease development and thus can be regarded as potential biomarkers and therapeutic targets in atherosclerosis. The aim of the current study is to investigate the expression levels of atherosclerosis-associated miR-143 and miR-145 in Hhcy patients and predict the progress of atherosclerosis in Hhcy patients.

Methods

A total of 100 participants were enrolled and included normal control subjects (NC = 20), hyperhomocysteinaemia alone subjects (Hhcy = 25), hyperhomocysteinaemia and carotid artery atherosclerosis combined subjects (Hhcy + ATH = 30) and patients with standalone carotid artery atherosclerosis (ATH = 25). Plasma Hcy, supplementary biochemical parameters and carotid artery ultrasonography (USG) were measured in all participants. MicroRNA expression levels in the peripheral blood were calculated by real-time reverse transcription-polymerase chain reaction (qRT-PCR). The correlations of miR-143 and miR-145 with Hcy, blood lipid parameters and carotid artery atherosclerotic plaques were evaluated using Pearson’s correlation coefficients. Receiver operating characteristic (ROC) curve analyses were performed to evaluate the capacities of miR-143 and miR-145 for the detection of Hhcy and atherosclerosis patients.

Results

MiR-143 and miR-145 exhibited trends towards significance with stepwise decreases from the NC to Hhcy groups and then to the Hhcy + ATH and ATH groups. Similar results were observed in the carotid artery plaque group (Hhcy + ATH and ATH grups) compared with the no-plaque group (NC and Hhcy groups). The miR-143 expression level exhibited significant negative correlations with Hcy, total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c). The miR-145 expression level exhibited significant negative correlations with Hcy, TC, triglyceride (TG) and LDL-c. MiR-143 and miR-145 exhibited the greatest area under the curves (AUCs) (0.775 and 0.681, respectively) for the detection of every Hhcy patient, including those in the Hhcy and Hhcy + ATH groups, from among all subjects.

Conclusion

The results indicated that the levels of atherosclerosis-associated circulating miR-143 and miR-145 are linked to Hhcy. MiR-143 may be used as a potential non-invasive biomarkers of Hhcy and thus may be helpful in predicting the progress of atherosclerosis in Hhcy patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0596-0) contains supplementary material, which is available to authorized users.

H2S and homocysteine control a novel feedback regulation of cystathionine beta synthase and cystathionine gamma lyase in cardiomyocytes

Hydrogen sulfide (H₂S), a cardioprotective gas, is endogenously produced from homocysteine by cystathionine beta synthase (CBS) and cystathionine gamma lyase (CSE) enzymes. However, effect of H₂S or homocysteine on CBS and CSE expression, and cross-talk between CBS and CSE are unclear. We hypothesize that homocysteine and H₂S regulate CBS and CSE expressions in a dose dependent manner in cardiomyocytes, and CBS deficiency induces cardiac CSE expression. To test the hypothesis, we treated murine atrial HL1 cardiomyocytes with increasing doses of homocysteine or Na₂S/GYY4137, a H₂S donor, and measured the levels of CBS and CSE. We found that homocysteine upregulates CSE but downregulates CBS whereas Na₂S/GYY4137 downregulates CSE but upregulates CBS in a dose-dependent manner. Moreover, the Na₂S-treatment downregulates specificity protein-1 (SP1), an inducer for CSE, and upregulates miR-133a that targets SP1 and inhibits cardiomyocytes hypertrophy. Conversely, in the homocysteine-treated cardiomyocytes, CBS and miR-133a were downregulated and hypertrophy was induced. In vivo studies using CBS+/-, a model for hyperhomocysteinemia, and sibling CBS+/+ control mice revealed that deficiency of CBS upregulates cardiac CSE, plausibly by inducing SP1. In conclusion, we revealed a novel mechanism for H₂S-mediated regulation of homocysteine metabolism in cardiomyocytes, and a negative feedback regulation between CBS and CSE in the heart.

Cross-talk of MicroRNA and hydrogen sulfide: A novel therapeutic approach for bone diseases

Bone homeostasis requires a balance between the bone formation of osteoblasts and bone resorption of osteoclasts to maintain ideal bone mass and bone quality. An imbalance in bone remodeling processes results in bone metabolic disorders such as osteoporosis. Hydrogen sulfide (H₂S), a gasotransmitter, has attracted the focus of many researchers due to its multiple physiological functions. It has been implicated in anti-inflammatory, vasodilatory, angiogenic, cytoprotective, anti-oxidative and anti-apoptotic mechanisms. H₂S has also been shown to exert osteoprotective activity through its anti-inflammatory and anti-oxidative effects. However, the underlying molecular mechanisms by which H₂S mitigates bone diseases are not completely understood. Experimental evidence suggests that H₂S may regulate signaling pathways by directly influencing a gene in the cascade or interacting with some other gasotransmitter (carbon monoxide or nitric oxide) or both. MicroRNAs (miRNAs) are short non-coding RNAs which regulate gene expression by targeting, binding and suppressing mRNAs; thus controlling cell fate. Certainly, bone remodeling is also regulated by miRNAs expression and has been reported in many studies. MicroRNAs also regulate H₂S biosynthesis. The inter-regulation of microRNAs and H₂S opens a new possibility for exploring the H₂S-microRNA crosstalk in bone diseases. However, the relationship between miRNAs, bone development, and H₂S is still not well explained. This review focuses on miRNAs and their roles in regulating bone remodeling and possible mechanisms behind H₂S mediated bone loss inhibition, H₂S-miRNAs crosstalk in relation to the pathophysiology of bone remodeling, and future perspectives for miRNA-H₂S as a therapeutic agent for bone diseases.

Hypermethylation: Causes and Consequences in Skeletal Muscle Myopathy

A detrimental consequence of hypermethylation is hyperhomocysteinemia (HHcy), that causes oxidative stress, inflammation, and matrix degradation, which leads to multi-pathology in different organs. Although, it is well known that hypermethylation leads to overall gene silencing and hypomethylation leads to overall gene activation, the role of such process in skeletal muscle dysfunction during HHcy condition is unclear. In this study, we emphasized the multiple mechanisms including epigenetic alteration by which HHcy causes skeletal muscle myopathy. This review also highlights possible role of methylation, histone modification, and RNA interference in skeletal muscle dysfunction during HHcy condition and potential therapeutic molecules, putative challenges, and methodologies to deal with HHcy mediated skeletal muscle dysfunction. We also highlighted that B vitamins (mainly B12 and B6), with folic acid supplementation, could be useful as an adjuvant therapy to reverse these consequences associated with this HHcy conditions in skeletal muscle. However, we would recommend to further study involving long-term trials could help to assess efficacy of the use of these therapeutic agents. J. Cell. Biochem. 118: 2108-2117, 2017. © 2017 Wiley Periodicals, Inc.

The role of hydrogen sulfide in homocysteine-induced cardiodynamic effects and oxidative stress markers in the isolated rat heart

This study aimed to assess the role of H2S in homocysteine-induced cardiodynamic effects in the isolated rat heart. The hearts were retrogradely perfused according to the Langendorff technique. The maximum and minimum rates of pressure in the left ventricle (dp/dt max, dp/dt min), systolic and diastolic left ventricular pressures (SLVP, DLVP), heart rate (HR), and coronary flow (CF) were measured. A spectrophotometrical method was used to measure the following oxidative stress markers: index of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), nitrite level (NO2−), superoxide anion radicals (O2•−), and hydrogen peroxide (H2O2) concentrations. The administration of 10 µmol/l DL-homocysteine (DL-Hcy) alone decreased dp/dt max, SLVP, and CF but did not change any oxidative stress parameters. The administration of 10 µmol/l DL-propargylglycine (DL-PAG) decreased all cardiodynamic parameters and increased the concentration of O2•−. The co-administration of DL-Hcy and DL-PAG induced a significant decrease in all estimated cardiodynamic parameters and decreased the concentration of NO2− and O2•− but increased the levels of TBARS and H2O2. Homocysteine shows a lower pro-oxidative effect in the presence of hydrogen sulfide (H2S), which indicates a potential anti-oxidative capacity of H2S.

Emerging role of hydrogen sulfide-microRNA crosstalk in cardiovascular diseases

Despite an obnoxious smell and toxicity at a high dose, hydrogen sulfide (H2S) is emerging as a cardioprotective gasotransmitter. H2S mitigates pathological cardiac remodeling by regulating several cellular processes including fibrosis, hypertrophy, apoptosis, and inflammation. These encouraging findings in rodents led to initiation of a clinical trial using a H2S donor in heart failure patients. However, the underlying molecular mechanisms by which H2S mitigates cardiac remodeling are not completely understood. Empirical evidence suggest that H2S may regulate signaling pathways either by directly influencing a gene in the cascade or interacting with nitric oxide (another cardioprotective gasotransmitter) or both. Recent studies revealed that H2S may ameliorate cardiac dysfunction by up- or downregulating specific microRNAs. MicroRNAs are noncoding, conserved, regulatory RNAs that modulate gene expression mostly by translational inhibition and are emerging as a therapeutic target for cardiovascular disease (CVD). Few microRNAs also regulate H2S biosynthesis. The inter-regulation of microRNAs and H2S opens a new avenue for exploring the H2S-microRNA crosstalk in CVD. This review embodies regulatory mechanisms that maintain the physiological level of H2S, exogenous H2S donors used for increasing the tissue levels of H2S, H2S-mediated regulation of CVD, H2S-microRNAs crosstalk in relation to the pathophysiology of heart disease, clinical trials on H2S, and future perspectives for H2S as a therapeutic agent for heart failure.

Medical Functions of Hydrogen Sulfide

Hydrogen sulfide (H(2)S) is a gasomediator synthesized from L- and D-cysteine in various tissues. It is involved in a number of physiological and pathological processes. H(2)S exhibits antiatherosclerotic, vasodilator, and proangiogenic properties, and protects the kidney and heart from damage following ischemia/reperfusion injury. H(2)S donors may be natural or synthetic, and may be used for the safe treatment of a wide range of diseases. This review article summarizes the current state of knowledge of the therapeutic function of H(2)S.