Angiotensin II induced differentially expressed microRNAs in adult rat cardiac fibroblasts

MicroRNAs and cardiac fibrosis: A comprehensive update on mechanisms and consequences

Fibrosis is a pathological wound-healing mechanism that results by the overactivation of fibroblasts. Fibrosis can become obstructive and deleterious during regeneration of various body tissues including cardiac muscle. This ultimately results in the development of cardiac fibrosis, characterized by an excessive buildup of extracellular matrix proteins. Thus, it could lead to arrhythmias and heart failure which creates a leading public health burden worldwide. MiRNAs are small non-coding RNAs with great potential for diagnostic and therapeutic purposes. Mounting evidence indicates that miRNAs are involved in the deregulation of tissue homeostasis during myocardial fibrosis. For instance, miRNAs that are implicated in the regulation of TGF-beta signaling pathway have been reported to be significantly altered in myocardial fibrosis. Accordingly, in this comprehensive review, we discuss and highlight recent available data on the role of miRNAs during myocardial fibrosis, providing valuable insights into the miRNA modulation of cardiac fibrosis and miRNAs targets that can be used in the future therapeutic interventions to cardiac fibrosis.

Epididymal white adipose tissue promotes angiotensin II-induced cardiac fibrosis in an exosome-dependent manner

Cardiac fibrosis is a process characterized by extracellular matrix accumulation leading to myocardial dysfunction. Angiotensin II (Ang II) has been shown to play an important role in the pathogenesis of cardiac fibrosis. However, the underlying mechanisms are not well established. Dysfunction of adipose tissue has been shown to promote remote organ injury, but its role in Ang II-induced cardiac remodeling is still unclear. In this study, we demonstrated that epididymal white adipose tissue (eWAT) promoted Ang II-induced cardiac fibrosis and subsequent cardiac dysfunction in an exosome-dependent manner. Both eWAT removal and administration of an inhibitor of exosome biogenesis strongly attenuated Ang II-induced abnormalities. Moreover, exosomes isolated from Ang II-stimulated adipocytes promoted cardiac fibroblasts (CFs) activity. A mechanistic study identified that the miR-23a-3p level was significantly increased in exosomes derived from Ang II-challenged adipocytes and serum exosomes from Ang II-infused mice. Importantly, tail vein injection of ago-miR-23a-3p caused cardiac fibrosis and dysfunction, while antago-miR-23a-3p inhibited Ang II-induced cardiac fibrosis. Bioinformatics analysis and further validation experiments revealed that RAP1 is a direct downstream target of miR-23a-3p, and overexpression of RAP1 reversed the profibrotic effect of miR-23a-3p. Taken together, these findings elucidated the role of eWAT in Ang II-induced myocardial fibrosis and indicated that adipocyte-derived exosomes mediate pathologic communication between dysfunctional adipose tissue and the heart by transporting miR-23a-3p into CFs, transforming fibroblasts into myofibroblasts and promoting excessive collagen deposition by targeting RAP1. Prevention of abnormal adipocyte exosome production, inhibition of miR-23a-3p biogenesis, and treatment with a miR-23a-3p antagonist are novel strategies for treating cardiac fibrosis.

Long-Term Strenuous Exercise Promotes Vascular Injury by Selectively Damaging the Tunica Media

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Long-term strenuous endurance training promotes a deleterious vascular remodeling, in contrast to the beneficial effects of moderate exercise.

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Tunica media fibrosis, possibly mediated by miR-212, miR-132, and miR-146b down-regulation, and intrinsic vascular smooth muscle cell stiffening may contribute to aortic stiffening.

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Endothelial function improves in a similar intensity after moderate and strenuous training. However, in the INT group, a larger NO-mediated vasorelaxation is compensated by more intense vasoconstriction, leading to a potentially unstable balance.

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Strenuous exercise-induced vascular stiffening and changes in endothelial function remain after ceasing physical activity.

Moderate exercise has well-founded benefits in cardiovascular health. However, increasing, yet controversial, evidence suggests that extremely trained athletes may not be protected from cardiovascular events as much as moderately trained individuals. In our rodent model, intensive but not moderate training promoted aorta and carotid stiffening and elastic lamina ruptures, tunica media thickening of intramyocardial arteries, and an imbalance between vasoconstrictor and relaxation agents. An up-regulation of angiotensin-converter enzyme, miR-212, miR-132, and miR-146b might account for this deleterious remodeling. Most changes remained after a 4-week detraining. In conclusion, our results suggest that intensive training blunts the benefits of moderate exercise.

CVD and COVID-19: Emerging Roles of Cardiac Fibroblasts and Myofibroblasts

Cardiovascular disease (CVD) is the leading cause of death worldwide. Current data suggest that patients with cardiovascular diseases experience more serious complications with coronavirus disease-19 (COVID-19) than those without CVD. In addition, severe COVID-19 appears to cause acute cardiac injury, as well as long-term adverse remodeling of heart tissue. Cardiac fibroblasts and myofibroblasts, being crucial in response to injury, may play a pivotal role in both contributing to and healing COVID-19-induced cardiac injury. The role of cardiac myofibroblasts in cardiac fibrosis has been well-established in the literature for decades. However, with the emergence of the novel coronavirus SARS-CoV-2, new cardiac complications are arising. Bursts of inflammatory cytokines and upregulation of TGF-β1 and angiotensin (AngII) are common in severe COVID-19 patients. Cytokines, TGF-β1, and Ang II can induce cardiac fibroblast differentiation, potentially leading to fibrosis. This review details the key information concerning the role of cardiac myofibroblasts in CVD and COVID-19 complications. Additionally, new factors including controlling ACE2 expression and microRNA regulation are explored as promising treatments for both COVID-19 and CVD. Further understanding of this topic may provide insight into the long-term cardiac manifestations of the COVID-19 pandemic and ways to mitigate its negative effects.

The Role of MicroRNAs in Endothelial Cell Senescence

Cellular senescence is a complex, dynamic process consisting of the irreversible arrest of growth and gradual deterioration of cellular function. Endothelial senescence affects the cell’s ability to repair itself, which is essential for maintaining vascular integrity and leads to the development of endothelial dysfunction, which has an important role in the pathogenesis of cardiovascular diseases. Senescent endothelial cells develop a particular, senescence-associated secretory phenotype (SASP) that detrimentally affects both surrounding and distant endothelial cells, thereby facilitating the ageing process and development of age-related disorders. Recent studies highlight the role of endothelial senescence and its dysfunction in the pathophysiology of several age-related diseases. MicroRNAs are small noncoding RNAs that have an important role in the regulation of gene expression at the posttranscriptional level. Recently, it has been discovered that miRNAs could importantly contribute to endothelial cell senescence. Overall, the research focus has been shifting to new potential mechanisms and targets to understand and prevent the structural and functional changes in ageing senescent endothelial cells in order to prevent the development and limit the progression of the wide spectrum of age-related diseases. The aim of this review is to provide some insight into the most important pathways involved in the modulation of endothelial senescence and to reveal the specific roles of several miRNAs involved in this complex process. Better understanding of miRNA’s role in endothelial senescence could lead to new approaches for prevention and possibly also for the treatment of endothelial cells ageing and associated age-related diseases.

Role of MicroRNAs and their corresponding ACE2/Apelin signaling pathways in hypertension

Hypertension is controlled via the alteration of microRNAs (miRNAs), their therapeutic targets angiotensin II type I receptor (AT1R) and cross talk of signaling pathways. The stimulation of the Ang II/AT1R pathway by deregulation of miRNAs, has also been linked to cardiac remodeling as well as the pathophysiology of high blood pressure. As miRNAs have been associated to ACE2/Apelin and Mitogen-activated protein kinases (MAPK) signaling, it has revealed an utmost protective impact over hypertension and cardiovascular system. The ACE2-coupled intermodulation between RAAS, Apelin system, MAPK signaling pathways, and miRNAs reveal the practicalities of high blood pressure. The research of miRNAs may ultimately lead to the expansion of an innovative treatment strategy for hypertension, which indicates the need to explore them further at the molecular level. Therefore, here we have focused on the mechanistic importance of miRNAs in hypertension, ACE2/Apelin signaling as well as their biological functions, with a focus on interplay and crosstalk between ACE2/Apelin signaling, miRNAs, and hypertension, and the progress in miRNA-based diagnostic techniques with the goal of facilitating the development of new hypertension-controlling therapeutics.

MicroRNAs Regulating Renin-Angiotensin-Aldosterone System, Sympathetic Nervous System and Left Ventricular Hypertrophy in Systemic Arterial Hypertension

MicroRNAs are small non-coding RNAs that regulate gene and protein expression. MicroRNAs also regulate several cellular processes such as proliferation, differentiation, cell cycle, apoptosis, among others. In this context, they play important roles in the human body and in the pathogenesis of diseases such as cancer, diabetes, obesity and hypertension. In hypertension, microRNAs act on the renin-angiotensin-aldosterone system, sympathetic nervous system and left ventricular hypertrophy, however the signaling pathways that interact in these processes and are regulated by microRNAs inducing hypertension and the worsening of the disease still need to be elucidated. Thus, the aim of this review is to analyze the pattern of expression of microRNAs in these processes and the possible associated signaling pathways.

Advances in miR-132-Based Biomarker and Therapeutic Potential in the Cardiovascular System

Atherosclerotic cardiovascular disease and subsequent heart failure threaten global health and impose a huge economic burden on society. MicroRNA-132 (miR-132), a regulatory RNA ubiquitously expressed in the cardiovascular system, is up-or down-regulated in the plasma under various cardiac conditions and may serve as a potential diagnostic or prognostic biomarker. More importantly, miR-132 in the myocardium has been demonstrated to be a master regulator in many pathological processes of ischemic or nonischemic heart failure in the past decade, such as myocardial hypertrophy, fibrosis, apoptosis, angiogenesis, calcium handling, neuroendocrine activation, and oxidative stress, through downregulating target mRNA expression. Preclinical and clinical phase 1b studies have suggested antisense oligonucleotide targeting miR-132 may be a potential therapeutic approach for ischemic or nonischemic heart failure in the future. This review aims to summarize recent advances in the physiological and pathological functions of miR-132 and its possible diagnostic and therapeutic potential in cardiovascular disease.

Cardiac-specific microRNA-125b deficiency induces perinatal death and cardiac hypertrophy

MicroRNA-125b, the first microRNA to be identified, is known to promote cardiomyocyte maturation from embryonic stem cells; however, its physiological role remains unclear. To investigate the role of miR-125b in cardiovascular biology, cardiac-specific miR-125b-1 knockout mice were generated. We found that cardiac-specific miR-125b-1 knockout mice displayed half the miR-125b expression of control mice resulting in a 60% perinatal death rate. However, the surviving mice developed hearts with cardiac hypertrophy. The cardiomyocytes in both neonatal and adult mice displayed abnormal mitochondrial morphology. In the deficient neonatal hearts, there was an increase in mitochondrial DNA, but total ATP production was reduced. In addition, both the respiratory complex proteins in mitochondria and mitochondrial transcription machinery were impaired. Mechanistically, using transcriptome and proteome analysis, we found that many proteins involved in fatty acid metabolism were significantly downregulated in miR-125b knockout mice which resulted in reduced fatty acid metabolism. Importantly, many of these proteins are expressed in the mitochondria. We conclude that miR-125b deficiency causes a high mortality rate in neonates and cardiac hypertrophy in adult mice. The dysregulation of fatty acid metabolism may be responsible for the cardiac defect in the miR-125b deficient mice.

Potential role of ACE2-related microRNAs in COVID-19-associated nephropathy

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for coronavirus disease (COVID-19), potentially have severe kidney adverse effects. This organ expressed angiotensin-converting enzyme 2 (ACE2), the transmembrane protein which facilitate the entering of the virus into the cell. Therefore, early detection of the kidney manifestations of COVID-19 is crucial. Previous studies showed ACE2 role in various indications of this disease, especially in kidney effects. The MicroRNAs (miRNAs) in this organ affected ACE2 expression. Therefore, this review aims at summarizing the literature of a novel miRNA-based therapy and its potential applications in COVID-19-associated nephropathy. Furthermore, previous studies were analyzed for the kidney manifestations of COVID-19 and the miRNAs role that were published on the online databases, namely MEDLINE (PubMed) and Scopus. Several miRNAs, particularly miR-18 (which was upregulated in nephropathy), played a crucial role in ACE2 expression. Therefore, the antimiR-18 roles were summarized in various primate models that aided in developing the therapy for ACE2 related diseases.

MicroRNAs and Adrenocortical Tumors: Where do we Stand on Primary Aldosteronism?

MicroRNAs, the endogenous mediators of RNA interference, interact with the renin-angiotensin-aldosterone system, regulate aldosterone secretion and aldosterone effects. Some novel data show that the expression of some microRNAs is altered in primary aldosteronism, and some of these appear to have pathogenic relevance, as well. Differences in the circulating microRNA expression profiles between the two major forms of primary aldosteronism, unilateral aldosterone-producing adenoma and bilateral adrenal hyperplasia have also been shown. Here, we present a brief synopsis of these findings focusing on the potential relevance of microRNA in primary aldosteronism.

Blockade of miR-140-3p prevents functional deterioration in afterload-enhanced engineered heart tissue

Afterload enhancement (AE) of rat engineered heart tissue (EHT) in vitro leads to a multitude of changes that in vivo are referred to as pathological cardiac hypertrophy: e.g., cardiomyocyte hypertrophy, contractile dysfunction, reactivation of fetal genes and fibrotic changes. Moreover AE induced the upregulation of 22 abundantly expressed microRNAs. Here, we aimed at evaluating the functional effect of inhibiting 7 promising microRNAs (miR-21-5p, miR-146b-5p, miR-31a-5p, miR-322-5p, miR-450a-5p, miR-140-3p and miR-132-3p) in a small-range screen. Singular transfection of locked nucleic acid (LNA)-based anti-miRs at 100 nM (before the one week AE-procedure) led to a powerful reduction of the targeted microRNAs. Pretreatment with anti-miR-146b-5p, anti-miR-322-5p or anti-miR-450a-5p did not alter the AE-induced contractile decline, while anti-miR-31a-5p-pretreatment even worsened it. Anti-miR-21-5p and anti-miR-132-3p partially attenuated the AE-effect, confirming previous reports. LNA-anti-miR against miR-140-3p, a microRNA recently identified as a prognostic biomarker of cardiovascular disease, also attenuated the AE-effect. To simplify future in vitro experiments and to create an inhibitor for in vivo applications, we designed shorter miR-140-3p-inhibitors and encountered variable efficiency. Only the inhibitor that effectively repressed miR-140-3p was also protective against the AE-induced contractile decline. In summary, in a small-range functional screen, miR-140-3p evolved as a possible new target for the attenuation of afterload-induced pathological cardiac hypertrophy.

Role of microRNAs in aldosterone signaling

PURPOSE OF REVIEW

The review describes studies investigating the role of microRNAs in the signaling pathway of the mineralocorticoid hormone, aldosterone.

RECENT FINDINGS

Emerging evidence indicates that aldosterone alters the expression of microRNAs in target tissues thereby modulating the expression of key regulatory proteins.

SUMMARY

The mineralocorticoid hormone aldosterone is released by the adrenal glands in a homeostatic mechanism to regulate blood volume. The long-term renal action of aldosterone is to increase the retrieval of sodium from filtered plasma to restore blood pressure. Emerging evidence indicates aldosterone may alter noncoding RNAs (ncRNAs) to integrate this hormonal response in target tissue. Expression of the best characterized small ncRNAs, microRNAs, is regulated by aldosterone stimulation. MicroRNAs modulate protein expression at all steps in the renin-angiotensin-aldosterone-signaling (RAAS) system. In addition to acting as a rheostat to fine-tune protein levels in aldosterone-responsive cells, there is evidence that microRNAs down-regulate components of the signaling cascade as a feedback mechanism. The role of microRNAs is, therefore, as signal integrator, and damper in aldosterone signaling, which has implications in understating the RAAS system from both a physiological and pathophysiological perspective. Recent evidence for microRNA's role in RAAS signaling will be discussed.

A novel mechanism of Smads/miR-675/TGFβR1 axis modulating the proliferation and remodeling of mouse cardiac fibroblasts

Cardiac fibroblasts (CFs) can over-proliferate during the progression of cardiac fibrosis, accompanied by a net accumulation of extracellular matrix proteins. Based on the profibrotic actions of transforming growth factor beta 1 (TGFβ1), investigating the mechanisms of TGFβ1 function in CFs may provide new directions to treatment for cardiac fibrosis. microRNAs (miRNAs) could control CFs proliferation or remodeling via binding to 3'-untranslated region of messenger RNA (mRNA) to negatively regulate gene expression. In the present study, we downloaded several microarray analyses results from GEO attempting to identify miRNAs and possible downstream targets that may be involved in TGF-β1 function in CFs and to detect the cellular and molecular functions of the identified miRNA-mRNA axis. Here, we identified miR-675 as a downregulated miRNA by TGFβ1 by bioinformatics analyses and experimental verification. Upon TGFβ1 stimulation, the protein levels of Α-SMAΑ-SMA, collagen I, and POSTN, and the secreted collagen in the cell culture supernatant significantly increased, whereas the miR-675 expression decreased. Smads mediate TGFβ1-induced suppression on miR-675 via binding miR-675 promoter region. miR-675 overexpression could inhibit, whereas miR-675 inhibition could enhance TGFβ1-induced mouse CFs (MCF) remodeling and proliferation. TGFβ receptor 1 (TGFβR1), a critical receptor in TGFβ1/Smad signaling, is a direct downstream target of miR-675. TGFβR1 overexpression significantly reverses the effect of miR-675 overexpression on MCF remodeling and proliferation. In summary, miR-675 targets TGFβR1 to attenuate TGFβ1-induced MCF remodeling and proliferation. We demonstrate a novel mechanism of the Smads/miR-675/TGFβR1 axis modulating TGFβ1-induced MCF remodeling and proliferation.

Regulation of Aldosterone Signaling by MicroRNAs

The mineralocorticoid hormone aldosterone is released by the adrenal glands in a homeostatic mechanism to regulate blood volume. Several cues elicit aldosterone release, and the long-term action of the hormone is to restore blood pressure and/or increase the retrieval of sodium from filtered plasma in the kidney. While the signaling cascade that results in aldosterone release is well studied, the impact of this hormone on tissues and cells in various organ systems is pleotropic. Emerging evidence indicates aldosterone may alter non-coding RNAs (ncRNAs) to integrate the hormonal response, and these ncRNAs may contribute to the heterogeneity of signaling outcomes in aldosterone target tissues. The best studied of the ncRNAs in aldosterone action are the small ncRNAs, microRNAs. MicroRNA expression is regulated by aldosterone stimulation, and microRNAs are able to modulate protein expression at all steps in the renin-angiotensin-aldosterone-signaling system. The discovery and synthesis of microRNAs will be briefly covered followed by a discussion of the reciprocal role of aldosterone/microRNA regulation, including misregulation of microRNA signaling in aldosterone-linked disease states.

The interplay of LncRNA ANRIL and miR-181b on the inflammation-relevant coronary artery disease through mediating NF-κB signalling pathway

This study was designed to investigate whether ANRIL affected the aetiology of coronary artery disease (CAD) by acting on downstream miR-181b and NF-κB signalling. Altogether 327 CAD patients diagnosed by angiography were included, and mice models of CAD were established. Human coronary endothelial cells (HCAECs) and human umbilical vein endothelial cells (HUVECs) were also purchased. In addition, shRNA-ANRIL, shRNA-NC, pcDNA3.1-ANRIL, miR-181b mimic, miR-181b inhibitor and miR-NC were transfected into the cells. The lipopolysaccharides (LPS) and pyrrolidine dithiocarbamate (PDTC) were also added to activate or deactivate NF-κB signalling. Both highly expressed ANRIL and lowly expressed miR-181b were associated with CAD population aged over 60 years old, with smoking history, with hypertension and hyperlipidemia, with CHOL H 4.34 mmol/L, TG ≥ 1.93 mmol/L and Hcy ≥ 16.8 μmol/L (all P < 0.05). Besides, IL-6, IL-8, NF-κB, TNF-α, iNOS, ICAM-1, VCAM-1 and COX-2 expressions observed within AD mice models were all beyond those within NC and sham-operated groups (P < 0.05). Also VEGF and HSP 70 were highly expressed within AD mice models than within NC and sham-operated mice (P < 0.05). Transfection of either pcDNA-ANRIL or miR-181b inhibitor could significantly fortify HCAECs' viability and put on their survival rate. At the meantime, the inflammatory factors and vascular-protective parameters were released to a greater level (P < 0.05). Finally, highly expressed ANRIL also notably bring down miR-181b expression and raise p50/p65 expressions within HCAECs (P < 0.05). The joint role of ANRIL, miR-181b and NF-κB signalling could aid in further treating and diagnosing CAD.

MiR-33 promotes myocardial fibrosis by inhibiting MMP16 and stimulating p38 MAPK signaling

Myocardial fibrosis occurs in the late stages of many cardiovascular diseases, and appears to be stimulated by various microRNAs (miRNAs). We previously found that miR-33 may stimulate cardiac remodeling. Here, we examined the involvement of miR-33 in myocardial fibrosis. Proximal left coronary descending artery occlusion was performed in rat, and antagomiR-33a was injected. Primary cardiac fibroblasts were cultured and transfected with miR-33a mimics and inhibitors. miR-33a levels were increased in the rat after surgery, and collagen deposition and heart fibrosis were observed in vivo. Inhibition of miR-33a suppressed fibroblast proliferation, reduced the mRNA and protein levels of collagen-related markers in vitro and in vivo, and rescued the histological damage in vivo. A dual-luciferase reporter system showed that matrix metalloproteinase 16 (MMP16) gene was the direct target of MiR-33a. These results suggest that miR-33 promoted myocardial fibrosis by inhibiting MMP16 and stimulating p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway. MiR-33 may act as a novel therapeutic target for treating myocardial fibrosis.

microRNA-181a downregulates deptor for TGFβ-induced glomerular mesangial cell hypertrophy and matrix protein expression

TGFβ contributes to mesangial cell hypertrophy and matrix protein increase in various kidney diseases including diabetic nephropathy. Deptor is an mTOR-interacting protein and suppresses mTORC1 and mTORC2 activities. We have recently shown that TGFβ-induced inhibition of deptor increases the mTOR activity. The mechanism by which TGFβ regulates deptor expression is not known. Here we identify deptor as a target of the microRNA-181a. We show that in mesangial cells, TGFβ increases the expression of miR-181a to downregulate deptor. Decrease in deptor augments mTORC2 activity, resulting in phosphorylation/activation of Akt kinase. Akt promotes inactivating phosphorylation of PRAS40 and tuberin, leading to stimulation of mTORC1. miR-181a-mimic increased mTORC1 and C2 activities, while anti-miR-181a inhibited them. mTORC1 controls protein synthesis via phosphorylation of translation initiation and elongation suppressors 4EBP-1 and eEF2 kinase. TGFβ-stimulated miR-181a increased the phosphorylation of 4EBP-1 and eEF2 kinase, resulting in their inactivation. miR-181a-dependent inactivation of eEF2 kinase caused dephosphorylation of eEF2. Consequently, miR-181a-mimic increased protein synthesis and hypertrophy of mesangial cells similar to TGFβ. Anti-miR-181a blocked these events in a deptor-dependent manner. Finally, TGFβ-miR-181a-driven deptor downregulation increased the expression of fibronectin. Our results identify a novel mechanism involving miR-181a-driven deptor downregulation, which contributes to mesangial cell pathologies in renal complications.

Identification of crucial miRNAs and the targets in renal cortex of hypertensive patients by expression profiles

BACKGROUNDS

Defect in kidney is one major reason of hypertension. The study aimed ao uncovering the regulatory mechanisms of miRNAs and the targets in hypertensive kidney.

METHODS

Gene expression profile of GSE28345 and miRNA expression profile of GSE28283 were downloaded from GEO database. After data preprocessing, differently expressed genes (DEGs) and miRNAs (DE-miRs) were identified using limma package. Then targets of miRNAs were predicted according to information in relevant databases. Function and pathway enrichment analyses were performed for DEGs using DAVID software. Furthermore, protein-protein interaction (PPI) networks were constructed for up- and down-regulated genes, respectively, using the Cytoscape. Additionally, for down-regulated DEGs, the integrated regulatory network was established combining PPI network with the miRNA-mRNA interactions.

RESULTS

As a result, 285 DEGs were identified, including 177 up-regulated and 108 down-regulated genes. Combined with the predicted targets of miRNAs, 22 up-regulated DE-miRs were identified. In the integrated network for down-regulated DEGs, three crucial nodes were identified as ASPN, COL12A1, and SCN2A. ASPN was predicted as target of miR-21 and miR-374b, and COL12A1 was the target of miR-30e, miR-21, and miR-195, while SCN2A was the target of miR-30e, miR-374b, and miR-195. Notably, COL12A1 and ASPN were linked with each other in the network.

CONCLUSION

Three crucial genes were identified in hypertensive kidney, such as COL12A1, ASPN, and SCN2A. ASPN might co-function with COL12A1, and they both might be the targets of miR-21. SCN2A might be a novel target of miR-30e and miR-374b. However, more experiments are needed to validate these results.

miR-181a and miR-150 regulate dendritic cell immune inflammatory responses and cardiomyocyte apoptosis via targeting JAK1-STAT1/c-Fos pathway

The immune inflammatory response plays a crucial role in many cardiac pathophysiological processes, including ischaemic cardiac injury and the post-infarction repair process. MicroRNAs (miRNAs) regulate the development and function of dendritic cells (DCs), which are key players in the initiation and regulation of immune responses; however, the underlying regulatory mechanisms remain unclear. Here, we used the supernatants of necrotic primary cardiomyocytes (Necrotic-S) to mimic the myocardial infarction (MI) microenvironment to investigate the role of miRNAs in the regulation of DC-mediated inflammatory responses. Our results showed that Necrotic-S up-regulated the DC maturation markers CD40, CD83 and CD86 and increased the production of inflammatory cytokines, concomitant with the up-regulation of miR-181a and down-regulation of miR-150. Necrotic-S stimulation activated the JAK/STAT pathway and promoted the nuclear translocation of c-Fos and NF-κB p65, and silencing of STAT1 or c-Fos suppressed Necrotic-S-induced DC maturation and inflammatory cytokine production. The effects of Necrotic-S on DC maturation and inflammatory responses, its activation of the JAK/STAT pathway and the induction of cardiomyocyte apoptosis under conditions of hypoxia were suppressed by miR-181a or miR-150 overexpression. Taken together, these data indicate that miR-181a and miR-150 attenuate DC immune inflammatory responses via JAK1-STAT1/c-Fos signalling and protect cardiomyocytes from cell death under conditions of hypoxia.

Circulating miR-19b and miR-181b are potential biomarkers for diabetic cardiomyopathy

Diabetic cardiomyopathy is characterized by metabolic changes in the myocardium that promote a slow and silent dysfunction of muscle fibers, leading to myocardium remodelling and heart failure, independently of the presence of coronary artery diseases or hypertension. At present, no imaging methods allow an early diagnosis of this disease. Circulating miRNAs in plasma have been proposed as biomarkers in the prognosis of several cardiac diseases. This study aimed to determine whether circulating miRNAs could be potential biomarkers of diabetic cardiomyopathy. Mice that were fed with a high fat diet for 16 months, showed metabolic syndrome manifestations, cardiac hypertrophy (without hypertension) and a progressive cardiac function decline. At 16 months, when maximal degree of cardiac dysfunction was observed, 15 miRNAs from a miRNA microarray screening in myocardium were selected. Then, selected miRNAs expression in myocardium (at 4 and 16 months) and plasma (at 4, 12 and 16 months) were measured by RT-qPCR. Circulating miR-19b-3p and miR-181b-5p levels were associated with myocardium levels during the development of diabetic cardiomyopathy (in terms of cardiac dysfunction), suggesting that these miRNAs could be suitable biomarkers of this disease in asymptomatic diabetic patients.

Long noncoding RNA: a new contributor and potential therapeutic target in fibrosis

Fibrosis is the excess deposition of extracellular matrix components which occur in multiple organs and ultimately leads to organ failure. Long noncoding RNAs (lncRNAs) are a kind of noncoding RNAs longer than approximately 200 nucleotides with no protein-encoding capacity. A growing body of evidence suggests that lncRNAs are also involved in tissues fibrosis in several organs, such as lungs fibrosis, liver fibrosis, renal fibrosis and cardiac fibrosis. In this review, we summarized the current studies of lncRNAs in the process of fibrosis and hopefully aid in better understanding the molecular mechanism of fibrosis and provide a basis to explore new therapeutic targets of fibrosis.

Molecular mechanism of miR-181b in heart disease due to pregnancy-induced hypertension syndrome

The present study aimed to investigate the molecular mechanisms of microRNA (miR)-181b in heart disease due to hypertensive disorders complicating pregnancy (HDCP) through regulating the expression of metallopeptidase inhibitor 3 (TIMP3). miR-181b expression was detected by reverse transcription-quantitative polymerase chain reaction in peripheral blood samples from patients with HDCP. These samples were analyzed for clinical pathological characteristics. The primary cardiomyocytes of rats were cultured in hypoxic conditions for 24 h, in which miR-181b expression was detected at different time points. The expression of TIMP3 was assessed in normal rat cardiomyocytes following transfection with miR-181b mimics by western blot analysis. The TIMP3 protein was also detected in cardiomyocytes following transfection with TIMP3 short interfering-RNA. The apoptosis rate of transfected cardiomyocytes was detected by flow cytometry following 24 h of culture in a hypoxic environment. Luciferase assay was applied to validate whether miR-181b binds to the 3' untranslated region of TIMP3 mRNA. miR-181b expression was significantly downregulated in the peripheral blood of patients with HDCP and the miR-181b expression was negatively associated with the grades of hypertension (P<0.05). The results of luciferase assay indicated that miR-181b directly targets TIMP3. The apoptosis rates of rat cardiomyocytes in the group transfected with miR-181b or TIMP3 siRNA was significantly lower than the normal control group (P<0.05). miR-181b may inhibit apoptosis of cardiomyocytes to protect myocardial cells through directly targeting TIMP3 genes, which serve important roles in HDCP.

micro-RNA screening and prediction model construction for diagnosis of salt-sensitive essential hypertension

Commonly used tests for diagnosis of salt-sensitive hypertension (SSH) are complex and time-consuming, so new methods are required. Many studies have demonstrated roles for miRNAs in hypertension; however, the diagnostic value of miRNAs has yet to be determined for human SSH. In this study, we examined miRNA expression profiles by initial high-throughput miRNA sequencing of samples from patients with salt-sensitive and salt-resistant hypertension (SSH and SRH, respectively; n = 6, both groups), followed by validation by quantitative real-time polymerase chain reaction (qRT-PCR) in a larger cohort (n = 91). We also evaluated differences in baseline characteristics (e.g., age, sex, body mass index, consumption of specific foods) between the SSH and SRH groups. Of 36 miRNAs identified as differentially expressed between SSH and SRH groups by RNA-Seq, 8 were analyzed by qRT-PCR. There were significant differences in the expression levels of hsa-miR-361-5p and hsa-miR-362-5p between the 2 groups (P = .023 and.049, respectively). In addition, there were significant differences in sauce and poultry consumption between the 2 groups (P = .004 and.001, respectively). The areas under the curve (AUC) determined by receptor operating characteristic (ROC) analysis for hsa-miR-361-5p and all 8 miRNAs were 0.793 (95% CI, 0.698-0.888; sensitivity = 73.9%, specificity = 74.4%; P < .001) and 0.836 (95% CI, 0.749-0.922; sensitivity = 80.4%, specificity = 81.4%; P < .001), respectively, when sauce and poultry consumption were included in the models. Assay feasibility and economic considerations make hsa-miR-361-5p combined with the dietary factors the preferred markers for diagnosis of SSH.

The effect of resveratrol on angiotensin II levels and the rate of transcription of its receptors in the rat cardiac hypertrophy model

This study investigated the effect of resveratrol on serum and cardiac levels of angiotensin II and transcription of its main receptors following pressure overload induced-hypertrophy. Rats were divided into untreated (Hyp) and resveratrol treated hypertrophied groups (H + R). Intact animals served as the control (Ctl). Cardiac hypertrophy was induced by abdominal aortic banding. Blood pressure (BP) was recorded via left carotid artery cannula. Fibrosis was confirmed by Masson trichrome staining. Angiotensin II level was measured using an ELIZA test. Gene expression was assessed by a real time PCR (RT-PCR) technique. We observed that in the H + R group BP and heart weight/body weight were decreased significantly (p < 0.001, p < 0.05, respectively vs Hyp). The cardiac levels of angiotensin II and AT1a mRNA were increased in the Hyp group (p < 0.01 vs Ctl). In the H + R group the AT1a mRNA level was decreased significantly (p < 0.05 vs Hyp). It could be concluded that resveratrol protects the heart against hypertrophy progression in part by affecting cardiac AT1a transcription.

Characterization of miRNA-regulated networks, hubs of signaling, and biomarkers in obstruction-induced bladder dysfunction

Bladder outlet obstruction (BOO) induces significant organ remodeling, leading to lower urinary tract symptoms accompanied by urodynamic changes in bladder function. Here, we report mRNA and miRNA transcriptome sequencing of bladder samples from human patients with different urodynamically defined states of BOO. Patients' miRNA and mRNA expression profiles correlated with urodynamic findings. Validation of RNA sequencing results in an independent patient cohort identified combinations of 3 mRNAs (NRXN3, BMP7, UPK1A) and 3 miRNAs (miR-103a-3p, miR-10a-5p, miR-199a-3p) sufficient to discriminate between bladder functional states. All BOO patients shared cytokine and immune response pathways, TGF-β and NO signaling pathways, and hypertrophic PI3K/AKT signaling pathways. AP-1 and NFkB were dominant transcription factors, and TNF-α was the top upstream regulator. Integrated miRNA-mRNA expression analysis identified pathways and molecules targeted by differentially expressed miRNAs. Molecular changes in BOO suggest an increasing involvement of miRNAs in the control of bladder function from the overactive to underactive/acontractile states.

Noncoding RNA as regulators of cardiac fibrosis: current insight and the road ahead

Cardiac fibrosis is an important pathological feature of cardiac remodeling in heart diseases. The molecular mechanisms of cardiac fibrosis are unknown. Genomic analyses estimated that many noncoding DNA regions generate noncoding RNAs (ncRNAs). ncRNAs have emerged as key molecular players in the regulation of gene expression in different biological processes. Recent studies have started to reveal the importance of ncRNAs in heart development and suggest also an involvement in cardiac fibrosis. These molecules are emerging as important regulators of cellular process. Here, we review particularly focuses on the involvement of two large families of ncRNAs, namely microRNAs (miRNAs) and long noncoding RNAs (LncRNAs) in the regulation of cardiac fibrosis. Furthermore, we review the functions and role of ncRNAs in cardiac biology and discuss these reports and the therapeutic potential of ncRNAs for cardiac fibrosis associated with fibroblast activation and proliferation.

Persistent phenotypic shift in cardiac fibroblasts: impact of transient renin angiotensin system inhibition

Fibrotic cardiac remodeling ultimately leads to heart failure - a debilitating and costly condition. Select antihypertensive agents have been effective in reducing or slowing the development of cardiac fibrosis. Moreover, some experimental studies have shown that the reduction in fibrosis induced by these agents persists long after stopping treatment. What has not been as well investigated is whether this transient treatment results in a protection against future fibrotic cardiac remodeling. In the present review, previously published studies are re-examined to assess whether the relative percent increase in collagen deposition over an off-treatment period is attenuated, relative to control, following transient antihypertensive treatment in young or adult rats. Present findings suggest that transient inhibition of the renin angiotensin system (RAS) not only produces a sustained reduction in cardiac fibrosis, but also results in a degree of protection against future collagen deposition. In addition, prior transient RAS inhibition appears to alter the cardiac fibroblast phenotype such that these cells show a muted response to myocardial injury - namely reduced proliferation, chemokine release, and collagen deposition. This review puts forth several potential mechanisms underlying this long-term cardiac protection that is afforded by transient RAS inhibition. Specifically, fibroblast phenotypic change, cardiac fibroblast apoptosis, sustained suppression of the RAS, persistent reduction in left ventricular hypertrophy, and persistent reduction in arterial pressure are each discussed. Identifying the mechanisms ultimately responsible for this change in cardiac fibroblast response to injury, hypertension, and aging may reveal novel targets for therapy.

MiR-125b Is Critical for Fibroblast-to-Myofibroblast Transition and Cardiac Fibrosis

BACKGROUND

Cardiac fibrosis is the pathological consequence of stress-induced fibroblast proliferation and fibroblast-to-myofibroblast transition. MicroRNAs have been shown to play a central role in the pathogenesis of cardiac fibrosis. We identified a novel miRNA-driven mechanism that promotes cardiac fibrosis via regulation of multiple fibrogenic pathways.

METHODS AND RESULTS

Using a combination of in vitro and in vivo studies, we identified that miR-125b is a novel regulator of cardiac fibrosis, proliferation, and activation of cardiac fibroblasts. We demonstrate that miR-125b is induced in both fibrotic human heart and murine models of cardiac fibrosis. In addition, our results indicate that miR-125b is necessary and sufficient for the induction of fibroblast-to-myofibroblast transition by functionally targeting apelin, a critical repressor of fibrogenesis. Furthermore, we observed that miR-125b inhibits p53 to induce fibroblast proliferation. Most importantly, in vivo silencing of miR-125b by systemic delivery of locked nucleic acid rescued angiotensin II-induced perivascular and interstitial fibrosis. Finally, the RNA-sequencing analysis established that miR-125b altered the gene expression profiles of the key fibrosis-related genes and is a core component of fibrogenesis in the heart.

CONCLUSIONS

In conclusion, miR-125b is critical for induction of cardiac fibrosis and acts as a potent repressor of multiple anti-fibrotic mechanisms. Inhibition of miR-125b may represent a novel therapeutic approach for the treatment of human cardiac fibrosis and other fibrotic diseases.

Persistent change in cardiac fibroblast physiology after transient ACE inhibition

Transient angiotensin-converting enzyme (ACE) inhibition induces persistent changes that protect against future nitric oxide synthase (NOS) inhibitor-induced cardiac fibrosis and inflammation. Given the role of fibroblasts in mediating these effects, the present study investigates whether prior ACE inhibition produced persistent changes in cardiac fibroblast physiology. Adult male spontaneously hypertensive rats (SHRs) were treated with vehicle (C+L) or the ACE inhibitor, enalapril (E+L) for 2 wk followed by a 2-wk washout period and a subsequent 7-day challenge with the NOS inhibitor N(ω)-nitro-l-arginine methyl ester. A third set of untreated SHRs served as controls. At the end of the study period, cardiac fibroblasts were isolated from control, C+L, and E+L left ventricles to assess proliferation rate, collagen expression, and chemokine release in vitro. After 7 days of NOS inhibition, there were areas of myocardial injury but no significant change in collagen deposition in E+L and C+L hearts in vivo. In vitro, cardiac fibroblasts isolated from C+L but not E+L hearts were hyperproliferative, demonstrated increased collagen type I gene expression, and an elevated secretion of the macrophage-recruiting chemokines monocyte chemoattractant protein-1 and granulocyte macrophage-colony stimulating factor. These findings demonstrate that in vivo N(ω)-nitro-l-arginine methyl ester treatment produces phenotypic changes in fibroblasts that persist in vitro. Moreover, this is the first demonstration that transient ACE inhibition can produce a persistent modification of the cardiac fibroblast phenotype to one that is less inflammatory and fibrogenic. It may be that the cardioprotective effects of ACE inhibition are related in part to beneficial changes in cardiac fibroblast physiology.

Effect of Ginkgo biloba extract on experimental cardiac remodeling

Background

To investigate the ameliorated effects of an extract of Ginkgo biloba extract (GBE) on experimental cardiac remodeling in rats induced by acute cardiac infarction, and further explore the mechanism concentrated on myocardial type I collagen, transforming growth factor beta 1 (TGF-β1), matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9), and provide the experimentaldata for clinical application of GBE.

Methods

Rats were divided into five groups (n = 20) as following: sham operation group (group A), acute myocardial infarction model group (group B), acute myocardial infarction model + aspirin (10 mg/kg) treatment group (group C), acute myocardial infarction model + captopril (20 mg/kg) treatment group (group D) and acute myocardial infarction model + Ginkgo biloba extract (100 mg/kg) treatment group (group E). The rat acute myocardial infarction model was reproduced by ligaturing the left anterior descending artery excluding the sham operation group which did not ligation only completed the operational process. Each group was further subdivided into treatment regimens lasting 4 weeks and 8 weeks. Immunohistochemistry and real-time polymerase chain reaction (PCR) methods were used to detect the protein expression and mRNA transcriptional levels of rat myocardial TGF-β1, type I collagen, MMP-2 and MMP-9.

Results

Compared with group B, regardless of the length of treatment (4 or 8 weeks), the TGF-β1, MMP-2 and MMP-9 mRNA transcriptional levels, and the protein expression levels of type I collagen, MMP-2 and MMP-9 in groups D, C and E were significantly decreased (P < 0.01). Furthermore, the mRNA expression levels of TGF-β1 in groups D, C and E were significantly lower after 8 weeks compared to after 4 weeks (P < 0.01), as were the expression levels of type I collagen in groups D, C and E (P < 0.05). There was no statistically significant difference in the protein expression levels of MMP-2 and MMP-9 between groups E and C.

Conclusions

GBE could inhibit experimental rat myocardial remodeling after acute myocardial infarction via reduced transcription of TGF-β1, MMP-2 and MMP-9 genes and by the decreased expression of type I collagen, MMP-2 and MMP-9 proteins in myocardial cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0719-z) contains supplementary material, which is available to authorized users.

Sp1 Mediates a Therapeutic Role of MiR-7a/b in Angiotensin II-Induced Cardiac Fibrosis via Mechanism Involving the TGF-β and MAPKs Pathways in Cardiac Fibroblasts

MicroRNA-7a/b (miR-7a/b) protects cardiac myocytes from apoptosis during ischemia/reperfusion injury; however, its role in angiotensin II (ANG II)-stimulated cardiac fibroblasts (CFs) remains unknown. Therefore, the present study investigated the anti-fibrotic mechanism of miR-7a/b in ANG II-treated CFs. ANG II stimulated the expression of specific protein 1 (Sp1) and collagen I in a dose- and time-dependent manner, and the overexpression of miR-7a/b significantly down-regulated the expression of Sp1 and collagen I stimulated by ANG II (100 nM) for 24 h. miR-7a/b overexpression effectively inhibited MMP-2 expression/activity and MMP-9 expression, as well as CF proliferation and migration. In addition, miR-7a/b also repressed the activation of TGF-β, ERK, JNK and p38 by ANG II. The inhibition of Sp1 binding activity by mithramycin prevented collagen I overproduction; however, miR-7a/b down-regulation reversed this effect. Further studies revealed that Sp1 also mediated miR-7a/b-regulated MMP expression and CF migration, as well as TGF-β and ERK activation. In conclusion, miR-7a/b has an anti-fibrotic role in ANG II-treated CFs that is mediated by Sp1 mechanism involving the TGF-β and MAPKs pathways.

Glomerulonephritis-Induced Changes in Urinary and Kidney MicroRNA Profiles in Rats

MicroRNAs (miRNAs) regulate gene expression post-transcriptionally and thus are involved in various physiological and pathological states. Due to their stability in biofluids miRNAs have also been proposed as biomarkers (BMs) for tissue injury. We investigated the usefulness of urinary miRNAs for detection of site-specific renal damage in an antiglomerular basement membrane glomerulonephritis (GN) model in rats by comparing GN-induced urinary miRNAs profiles to traditional and newer protein BMs, and to proximal tubular injury-induced urinary miRNA profiles observed previously after cisplatin (Cp) treatment. Male Wistar Kyoto and Sprague Dawley rats were dosed once with 1, 2.5, and 5 ml/kg nephrotoxic serum (NTS) or 1.5 and 5 ml/kg NTS, respectively. GN and tubular damage were observed histopathologically in all treated rats after 14 days. Although serum creatinine and BUN were not changed, several protein BMs and 74 urinary miRNAs were found to be increased 8 and 14 days after NTS administration. Of these 74 miRNAs, 5 were identified as increased after NTS but not after Cp treatment. Using in situ hybridization two of them, miR-10 b and -100, were found to be localized in distal segments of the nephron, potentially reflecting the tubular injury in those regions. Furthermore, evaluation of both miRNA and mRNA expression in the kidney revealed possible miRNA-mRNA interactions mostly associated with fibrotic and transforming growth factor β signaling. In conclusion, our investigations support the potential of urinary miRNAs as specific BMs for kidney injury, and suggest a role of miRNAs in pathological processes during GN in the kidney.

The ACE2/Apelin Signaling, MicroRNAs, and Hypertension

The renin-angiotensin aldosterone system (RAAS) plays a pivotal role in the development of hypertension. Angiotensin converting enzyme 2 (ACE2), which primarily metabolises angiotensin (Ang) II to generate the beneficial heptapeptide Ang-(1-7), serves as a negative regulator of the RAAS. Apelin is a second catalytic substrate for ACE2 and functions as an inotropic and cardiovascular protective peptide. The physiological effects of Apelin are exerted through binding to its receptor APJ, a seven-transmembrane G protein-coupled receptor that shares significant homology with the Ang II type 1 receptor (AT1R). The deregulation of microRNAs, a class of short and small noncoding RNAs, has been shown to involve cardiovascular remodeling and pathogenesis of hypertension via the activation of the Ang II/AT1R pathway. MicroRNAs are linked with modulation of the ACE2/Apelin signaling, which exhibits beneficial effects in the cardiovascular system and hypertension. The ACE2-coupled crosstalk among the RAAS, the Apelin system, and microRNAs provides an important mechanistic insight into hypertension. This paper focuses on what is known about the ACE2/Apelin signaling and its biological roles, paying particular attention to interactions and crosstalk among the ACE2/Apelin signaling, microRNAs, and hypertension, aiming to facilitate the exploitation of new therapeutic medicine to control hypertension.

Non-coding RNAs and hypertension-unveiling unexpected mechanisms of hypertension by the dark matter of the genome

Hypertension is a major risk factor of cardiovascular diseases and a most important health problem in developed countries. Investigations on pathophysiology of hypertension have been based on gene products from coding region that occupies only about 1% of total genome region. On the other hand, non-coding region that occupies almost 99% of human genome has been regarded as "junk" for a long time and went unnoticed until these days. But recently, it turned out that noncoding region is extensively transcribed to non-coding RNAs and has various functions. This review highlights recent updates on the significance of non-coding RNAs such as micro RNAs and long non-coding RNAs (lncRNAs) on the pathogenesis of hypertension, also providing an introduction to basic biology of noncoding RNAs. For example, microRNAs are associated with hypertension via neuro-fumoral factor, sympathetic nerve activity, ion transporters in kidneys, endothelial function, vascular smooth muscle phenotype transformation, or communication between cells. Although reports of lncRNAs on pathogenesis of hypertension are scarce at the moment, new lncRNAs in relation to hypertension are being discovered at a rapid pace owing to novel techniques such as microarray or next-generation sequencing. In the clinical settings, clinical use of non-coding RNAs in identifying cardiovascular risks or developing novel tools for treating hypertension such as molecular decoy or mimicks is promising, although improvement in chemical modification or drug delivery system is necessary.

Regulatory RNAs and paracrine networks in the heart

Cardiac hypertrophy and fibrosis are two closely related adaptive response mechanisms of the myocardium to mechanical, metabolic, and genetic stress that finally contribute to the development of heart failure (HF). This relation is based on a dynamic interplay between many cell types including cardiomyocytes and fibroblasts during disease progression. Both cell types secrete a variety of growth factors, cytokines, and hormones that influence hypertrophic cardiomyocyte growth and fibrotic fibroblast activation in a paracrine and autocrine manner. It has become evident that, aside proteinous signals, microRNAs (miRNAs) and possible other RNA species such as long non-coding RNAs are potential players in such a cell-to-cell communication. By directly acting as paracrine signals or by modulating downstream intercellular signalling mediators, miRNAs can act as moderators of the intercellular crosstalk. These small regulators can potentially be secreted in a 'mircrine' fashion, so that miRNAs can be assumed as the message itself. This review will summarize the recent findings about the paracrine crosstalk between cardiac fibroblasts and cardiomyocytes and addresses how miRNAs may be involved in this interplay. It also highlights therapeutic strategies targeting factors of pathological communication for the treatment of HF.

Role of miR-181 family in regulating vascular inflammation and immunity

The microRNA family, miR-181, plays diverse roles in regulating key aspects of cellular growth, development, and activation. Accumulating evidence supports a central role for the miR-181 family in vascular inflammation by controlling critical signaling pathways, such as downstream NF-κB signaling, and targets relevant to endothelial cell activation and immune cell homeostasis. This review examines the current knowledge of the miR-181 family's role in key cell types that critically control cardiovascular inflammation under pathological and physiological stimuli.

MicroRNAs: new insights into the pathogenesis of endodontic periapical disease

INTRODUCTION

Apical periodontitis is an inflammatory disease of the periradicular tissues caused by the host's immune response to infection of the root canal system. MicroRNAs (miRNAs) have been shown to play an important role in the regulation of inflammation and the immune response; however, their role in the pathogenesis of endodontic periapical disease has not been explored. The purpose of this study was to examine the differential expression of miRNAs in diseased periapical tissues as compared with healthy controls.

METHODS

We first compared miRNA profiles in diseased periapical tissues collected from patients undergoing endodontic surgery with those of healthy pulps by using microarray analyses. The target genes of the differentially expressed miRNAs were identified by using miRWalk and PubMed. Selected miRNAs linked to inflammation and the immune response were then confirmed in a separate cohort of diseased and healthy tissues by using quantitative reverse transcription-polymerase chain reaction. Healthy pulps and periodontal ligaments were used as controls. Data were normalized to the level of SNORD 44, which served as an endogenous control.

RESULTS

Of the 381 miRNAs identified by using microarray, 24 miRNAs were down-regulated in diseased periapical tissues compared with controls (n = 13) (P < .003). The down-regulation of 7 miRNAs was confirmed from 9 selected miRNAs by using quantitative real-time polymerase chain reaction (n = 19) (P < .05). Target genes of these miRNAs include key mediators in the immune and inflammatory response such as interleukin-6, matrix metalloproteinase-9, and transforming growth factor-β.

CONCLUSIONS

These findings offer new insight into the pathogenesis of endodontic disease and have the potential to impact the development of new methods for prevention, diagnosis, and treatment of apical periodontitis.

Angiotensin II upregulated the expression of microRNA-224 but not microRNA-21 in adult rat cardiac fibroblasts

The role of microRNA-21 (miRNA-21, miR-21) in cardiac fibrosis remains controversial, while the role of microRNA-224 (miRNA-224, miR-224) in cardiac fibroblasts has not been reported. Angiotensin II (Ang II) is known to play a pivotal role in the pathogenesis of cardiac fibrosis. The aim of this study was to confirm whether the expression of miR-21 and miR-224 is regulated by Ang II in adult rat cardiac fibroblasts. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and quantitative PCR (qPCR) were performed to measure the levels of miR-21 and miR-224 in Ang II-treated or untreated adult rat cardiac fibroblasts. The RT-PCR, qPCR and previous miRNA array results demonstrated that treatment with Ang II (100 nM) for 24 h did not induce the increase of miR-21 in cardiac fibroblasts, although the level of miR-21 in cardiac fibroblasts was not considered as low. The results of the present study also demonstrated that Ang II significantly upregulated the expression of miR-224 in adult rat cardiac fibroblasts. Bioinformatic analysis revealed that the potential target genes of miR-224 included SMAD4, SMAD5, cyclin-dependent kinase 9 and early growth response 1/2. In previous studies, it was reported that miR-224 was upregulated in tumors by promoting cell proliferation and targeting SMAD4. Those results indicated the potential roles of miR-224 in cardiac fibroblasts and cardiac fibrosis. In conclusion, results of the present study demonstrated that miR-21 was not induced by Ang II, whereas Ang II upregulated miR-224 expression in adult rat cardiac fibroblasts, a finding that may provide a starting point for the investigation of the potential role of miR-224 in cardiac fibrosis.

Epigenetic regulation of cardiac fibrosis

Cardiac fibrosis is characterized by excessive extracellular matrix accumulation that ultimately destroys tissue architecture and eventually abolishes normal function. In recent years, despite the underlying mechanisms of cardiac fibrosis are still unknown, numerous studies suggest that epigenetic modifications impact on the development of cardiac fibrosis. Epigenetic modifications control cell proliferation, differentiation, migration, and so on. Epigenetic modifications contain three main processes: DNA methylation, histone modifications, and silencing by microRNAs. We here outline the recent work pertaining to epigenetic changes in cardiac fibrosis. This review focuses on the epigenetic regulation of cardiac fibrosis.