miR-1, miR-499 and miR-208 are sensitive markers to diagnose sudden death due to early acute myocardial infarction

Identification of the miRNA-3185/CYP4A11 axis in cardiac tissue as a biomarker for mechanical asphyxia

Death by mechanical asphyxia is one of the most difficult conclusions to make in forensic science, especially in corpses displaying slight or no trauma to the surface of the body. Therefore, death by mechanical asphyxia is difficult to prove in medico-legal practice. MicroRNAs (miRNAs) are a class of small, non-coding RNAs involved in the regulation of numerous physiological and pathological cellular processes. In the present study, we demonstrate that significantly increased expression of miR-3185 in cardiac tissues was detected among cases of mechanical asphyxia compared to case of craniocerebral injury, hemorrhagic shock, sudden cardiac death and poisoning. We observed no correlation between the expression of miR-3185 and postmortem interval, age or temperature. Further work indicated that CYP4A11 is a putative target gene of miR-3185 and expressed at a relatively low level in cardiac tissue specimens from cases of mechanical asphyxia compared with specimens from cases of craniocerebral injury, hemorrhagic shock, sudden cardiac death and poisoning. Our results suggest that the miRNA-3185/CYP4A11 axis is associated with mechanical asphyxia-induced death and may provide new insight into asphyxial death investigations.

Inhibition of long non-coding RNA TUG1 protects against diabetic cardiomyopathy induced diastolic dysfunction by regulating miR-499-5p

Reportedly, several long non-coding RNAs (lncRNAs) have been involved in the regulation of cardiac hypertrophy induced by diabetic cardiomyopathy (DCM), causing cardiac dysfunction and subsequent failure. Although lncRNA taurine upregulated gene 1 (TUG1) is associated with myocardial injury, the expression profile and potential role of TUG1 in DCM-related cardiac hypertrophy remain unknown. This study elucidated the functions of TUG1 in DCM and its underlying mechanisms. Our results demonstrated that the expression of TUG1 was upregulated in db/db mice cardiomyocytes. Inhibition of TUG1 by lentivirus si-TUG1 indicated no effect on systolic function; however, it effectively improved DCM-induced diastolic dysfunction in db/db mice. TUG1 silencing demonstrated no influence on the metabolic characteristics of DCM, including blood glucose and lipid levels. Notably, TUG1 knockdown significantly decreased cardiac hypertrophy and reduced the fibrotic area, in vivo. To further investigate the underlying mechanism, miR-499-5p was predicted as the targeted TUG1 microRNA. The RT-qPCR and luciferase activity results confirmed that TUG1 negatively regulated miR-499-5p in cardiomyocytes. Furthermore, the overexpression of miR-499-5p abated the inhibitory effects of TUG1 silencing on high glucose-mediated cardiac hypertrophy, in vitro. Collectively, our study suggested that TUG1 knockdown attenuated DCM-induced cardiac hypertrophy and diastolic dysfunction by upregulating miR-499-5p. lncRNA TUG1 may be a novel potential target for DCM therapy.

CircCBFB-mediated miR-28-5p facilitates abdominal aortic aneurysm via LYPD3 and GRIA4

HEADING AIMS

Abdominal aortic aneurysm (AAA) is featured by the growth impediment and apoptosis surge of VSMCs (vascular smooth muscle cells). MicroRNAs (miRNAs) are suggested to affect cellular behaviors including cell growth and apoptosis. This study concentrated on unraveling the emerging role of miR-28-5p in abdominal aortic aneurysm.

MATERIALS AND METHODS

Previously, miR-28-5p was reported to be highly expressed in AAA. Functional assays were utilized to determine the role of miR-28-5p in VSMC apoptosis. To narrow down the downstream mRNAs, bioinformatics methods were utilized. The interaction between miR-28-5p and GRIA4 (glutamate ionotropic receptor AMPA type subunit 4) or LYPD3 (LY6/PLAUR domain containing 3) was explored. Candidate circRNAs (circular RNAs) of miR-28-5p were identified. Rescue analyses validated function of circCBFB (core-binding factor subunit beta)/miR-28-5p/GRIA4/LYPD3 axis in VSMC apoptosis and growth.

KEY FINDINGS

MiR-28-5p acted as an apoptosis driver while circCBFB, GRIA4 and LYPD3 exerted anti-apoptosis effects in VSMCs. Mechanically, GRIA4 and LYPD3 were suppressed by miR-28-5p. Moreover, circCBFB served as a sponge of miR-28-5p, releasing GRIA4 and LYPD3 from miR-28-5p suppression. Functionally, GRIA4, LYPD3 and miR-28-5p were required in circCBFB-mediated VSMC apoptosis.

SIGNIFICANCE

This work unveiled an innovative axis of circCBFB/miR-28-5p/GRIA4/LYPD3 in VSMC apoptosis, exerting its potential in providing new thoughts in AAA management.

Potential Clinical Implications of miR-1 and miR-21 in Heart Disease and Cardioprotection

The interest in non-coding RNAs, which started more than a decade ago, has still not weakened. A wealth of experimental and clinical studies has suggested the potential of non-coding RNAs, especially the short-sized microRNAs (miRs), to be used as the new generation of therapeutic targets and biomarkers of cardiovascular disease, an ever-growing public health issue in the modern world. Among the hundreds of miRs characterized so far, microRNA-1 (miR-1) and microRNA-21 (miR-21) have received some attention and have been associated with cardiac injury and cardioprotection. In this review article, we summarize the current knowledge of the function of these two miRs in the heart, their association with cardiac injury, and their potential cardioprotective roles and biomarker value. While this field has already been extensively studied, much remains to be done before research findings can be translated into clinical application for patient’s benefit.

MicroRNAs: The New Challenge for Traumatic Brain Injury Diagnosis

The acronym TBI refers to traumatic brain injury, an alteration of brain function, or an evidence of brain pathology, that is caused by an external force. TBI is estimated to become the third leading cause of permanent disability and mortality worldwide. TBI-related injuries can be classified in many ways, according to the degree of severity or the pathophysiology of brain injury (primary and secondary damage). Numerous cellular pathways act in secondary brain damage: excitotoxicity (mediated by excitatory neurotransmitters), free radical generation (due to mitochondrial impairment), neuroinflammatory response (due to central nervous system and immunoactivation) and apoptosis. In this scenario, microRNAs are implicated in the regulation of almost all genes at the post-transcriptional level. Several microRNAs have been demonstrated to be specifically expressed in particular cerebral areas; moreover, physiological changes in microRNA expression during normal cerebral development upon the establishment of neural networks have been characterized. More importantly, microRNAs show profound alteration in expression in response to brain pathological states, both traumatic or not. This review summarizes the most important molecular networks involved in TBI and examines the most recent and important findings on TBI-related microRNAs, both in animal and clinical studies. The importance of microRNA research holds promise to find biomarkers able to unearth primary and secondary molecular patterns altered upon TBI, to ultimately identify key points of regulation, as a valuable support in forensic pathology and potential therapeutic targets for clinical treatment.

miR-1, miR-499 and miR-208 are sensitive markers to diagnose sudden death due to early acute myocardial infarction

MicroRNAs (miRNAs) are strongly up-regulated under pathological stress and in a wide range of diseases. In recent years, miRNAs are under investigation for their potential use as biomarkers in cardiovascular diseases. We investigate whether specific cardio-miRNAs are overexpressed in heart samples from subjects deceased for acute myocardial infarction (AMI) or sudden cardiac death (SCD), and whether miRNA could help differentiate between them. Forty four cases of death due to cardiovascular disease were selected, respectively, 19 cases categorized as AMI and 25 as SCD. Eighteen cases of traumatic death without pathological cardiac involvement were selected as control. Immunohistochemical investigation was performed for CD15, IL-15, Cx43, MCP-1, tryptase, troponin C and troponin I. Reverse transcription and quantitative real-time PCR were performed for miR-1, miR-133, miR-208 and miR-499. In AMI group, stronger immunoreaction for the CD15, IL-15 and MCP-1 antibodies was detectable compared with SCD and control. Cx43 showed a negative reaction with respect to the other groups. Real-time PCR results showed a down-regulation of all miRNAs in the AMI group compared with SCD and control. The selected miRNAs presented high accuracy in discriminating SCD from AMI (miR-1 and miR-499) and AMI from control (miR-208) representing a potential aid for both clinicians and pathologists for differential diagnosis.