Novel insights toward human stroke-related epigenetics: circular RNA and its impact in poststroke processes

Identification of a valuable gene network for the diagnosis and treatment of non-obstructive azoospermia: in-silico analyses - experimental research

Introduction

Non-obstructive azoospermia (NOA) is an etiology of infertility in men. NOA may have various classifications; however, hypogonadotropic hypogonadism can be regarded as a class of NOA associated with genetic factors. Former studies have shown that noncoding RNA (ncRNA) plays an essential role in NOA incidence, but few studies have been performed on the NOA-related ncRNA interaction network. In the current study, genes, NOA-related microRNA (miRNA), and circular RNA (circRNA) were found by bioinformatics methods to offer a new perspective on NOA treatment.

Methods

The gonadotropin-releasing hormone receptor (GnRHR)-related protein-protein interaction (PPI) network was extracted by searching in 'string-database'. GO, KEGG, and Enrichr databases were used to identify pathways, molecular function, and biological processing. Four databases, including TargetScan, mirDIP, miRmap, and miRWalk, were used to extract miRNAs. At last, the circ2GO, circBase, and literature were used to identify circRNAs and their genes.

Results

The current study identified the four proteins associated with the GnRHR signaling; eight shared miRNAs that affect the expression of found proteins and 25 circRNAs and their origin genes that regulate the miRNAs' function.

Conclusion

The two miRNAs, hsa-miR-134-3p and hsa-miR-513C-3p, the three genes, VCAN, NFATC3, and PRDM5, and their associated circRNAs can perform as a valuable gene network in the diagnosis and treatment of NOA pathogenesis.

The regulation of circRNA and lncRNAprotein binding in cardiovascular diseases: Emerging therapeutic targets

Noncoding ribonucleic acids (ncRNAs) are a class of ribonucleic acids (RNAs) that carry cellular information and perform essential functions. This class encompasses various RNAs, such as small nuclear ribonucleic acids (snRNA), small interfering ribonucleic acids (siRNA) and many other kinds of RNA. Of these, circular ribonucleic acids (circRNAs) and long noncoding ribonucleic acids (lncRNAs) are two types of ncRNAs that regulate crucial physiological and pathological processes, including binding, in several organs through interactions with other RNAs or proteins. Recent studies indicate that these RNAs interact with various proteins, including protein 53, nuclear factor-kappa B, vascular endothelial growth factor, and fused in sarcoma/translocated in liposarcoma, to regulate both the histological and electrophysiological aspects of cardiac development as well as cardiovascular pathogenesis, ultimately leading to a variety of genetic heart diseases, coronary heart disease, myocardial infarction, rheumatic heart disease and cardiomyopathies. This paper presents a thorough review of recent studies on circRNA and lncRNAprotein binding within cardiac and vascular cells. It offers insight into the molecular mechanisms involved and emphasizes potential implications for treating cardiovascular diseases.

Clinical Application of Circular RNAs as Biomarkers in Acute Ischemic Stroke

Despite the substantial improvement in diagnosis and treatment within the last decades, ischemic stroke still represents a challenge, responsible still for a high burden of morbidity and mortality. Among the unmet clinical needs are the difficulties in identifying those subjects with the greatest risk of developing a stroke, the challenges in obtaining a timely diagnosis, the prompt recognition of the different clinical forms of stroke, the assessment of the response to treatments and the prognostic assessment. All these issues might be improved with appropriate smart biomarkers that could better inform clinical management. The present article offers an overview of the potential role of circular RNAs as disease biomarkers in stroke. A systematic approach was adopted to gather all potentially relevant information in order to provide a panoramic view on this class of promising molecules.

A systematic review of the research progress of non-coding RNA in neuroinflammation and immune regulation in cerebral infarction/ischemia-reperfusion injury

Cerebral infarction/ischemia-reperfusion injury is currently the disease with the highest mortality and disability rate of cardiovascular disease. Current studies have shown that nerve cells die of ischemia several hours after ischemic stroke, which activates the innate immune response in the brain, promotes the production of neurotoxic substances such as inflammatory cytokines, chemokines, reactive oxygen species and − nitrogen oxide, and mediates the destruction of blood-brain barrier and the occurrence of a series of inflammatory cascade reactions. Meanwhile, the expression of adhesion molecules in cerebral vascular endothelial cells increased, and immune inflammatory cells such as polymorphonuclear neutrophils, lymphocytes and mononuclear macrophages passed through vascular endothelial cells and entered the brain tissue. These cells recognize antigens exposed by the central nervous system in the brain, activate adaptive immune responses, and further mediate secondary neuronal damage, aggravating neurological deficits. In order to reduce the above-mentioned damage, the body induces peripheral immunosuppressive responses through negative feedback, which increases the incidence of post-stroke infection. This process is accompanied by changes in the immune status of the ischemic brain tissue in local and systemic systems. A growing number of studies implicate noncoding RNAs (ncRNAs) as novel epigenetic regulatory elements in the dysfunction of various cell subsets in the neurovascular unit after cerebral infarction/ischemia-reperfusion injury. In particular, recent studies have revealed advances in ncRNA biology that greatly expand the understanding of epigenetic regulation of immune responses and inflammation after cerebral infarction/ischemia-reperfusion injury. Identification of aberrant expression patterns and associated biological effects of ncRNAs in patients revealed their potential as novel biomarkers and therapeutic targets for cerebral infarction/ischemia-reperfusion injury. Therefore, this review systematically presents recent studies on the involvement of ncRNAs in cerebral infarction/ischemia-reperfusion injury and neuroimmune inflammatory cascades, and elucidates the functions and mechanisms of cerebral infarction/ischemia-reperfusion-related ncRNAs, providing new opportunities for the discovery of disease biomarkers and targeted therapy. Furthermore, this review introduces clustered regularly interspaced short palindromic repeats (CRISPR)-Display as a possible transformative tool for studying lncRNAs. In the future, ncRNA is expected to be used as a target for diagnosing cerebral infarction/ischemia-reperfusion injury, judging its prognosis and treatment, thereby significantly improving the prognosis of patients.

CircUSP36 attenuates ischemic stroke injury through the miR-139-3p/SMAD3/Bcl2 signal axis

Circular RNAs (circRNAs) play important roles in a variety of physiological and pathological processes. Researches demonstrated that circRNAs provided novel strategies for the prevention and treatment of IS. However, the biological function of hsa_circ_0045932 (circUSP36) has not been revealed yet. Here, we explored the effect of circUSP36 on IS and its mechanism. In this study, we found that circUSP36 expression was significantly decreased in the peripheral blood of IS patients and was negatively correlated with the severity, infarct volume and poor prognosis of IS. Functionally, circUSP36 silencing inhibited cellular activity and proliferation and promoted apoptosis after oxygen-glucose deprivation/reperfusion (OGD/R) treatment, while circUSP36 overexpression reversed these cellular phenotypes in vitro. Adeno-associated virus (AAV)-mediated overexpression of circUSP36 attenuates brain injury and neurological deficit and promotes motor function recovery of transient middle cerebral artery occlusion (tMCAO) mice. Subsequently, the RNA antisense purification (RAP) and luciferase reporter assay confirmed that circUSP36 acts as a sponge to adsorb miR-139-3p, and miR-139-3p could bind and inhibit SMAD3 expression. Further rescue experiments showed that both miR-139-3p overexpression and SMAD3 silencing could abolish the antiapoptotic effect of circUSP36. In summary, we reveal for the first time that circUSP36 attenuates ischemic stroke injury through the miR-139-3p/SMAD3/Bcl2 signal axis, which make circUSP36 a potential therapeutic target for IS.

Impact of CircRNAs on Ischemic Stroke

Circular RNA (circRNA) is a recently discovered class of endogenous non-coding RNA that is generated by cyclization, driven by intron pairing, and regulated by related regulators. An important biological function of CircRNA is acting as a molecular sponge to significantly alter miRNA levels over a short period. Several studies have shown that circRNA is closely related to stroke. Therefore, a better understanding of CircRNA function and regulatory mechanism in ischemic brain will help us for the early detection, early diagnosis, and early treatment of stroke. Here, we summary the biological characteristics, expression of circRNA, and its effect on outcome after ischemic stroke.

Noncoding RNAs and Their Response Predictive Value in Azacitidine-treated Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia With Myelodysplasia-related Changes

BACKGROUND/AIM

Prediction of response to azacitidine (AZA) treatment is an important challenge in hematooncology. In addition to protein coding genes (PCGs), AZA efficiency is influenced by various noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular RNAs (circRNAs), and transposable elements (TEs).

MATERIALS AND METHODS

RNA sequencing was performed in patients with myelodysplastic syndromes or acute myeloid leukemia before AZA treatment to assess contribution of ncRNAs to AZA mechanisms and propose novel disease prediction biomarkers.

RESULTS

Our analyses showed that lncRNAs had the strongest predictive potential. The combined set of the best predictors included 14 lncRNAs, and only four PCGs, one circRNA, and no TEs. Epigenetic regulation and recombinational repair were suggested as crucial for AZA response, and network modeling defined three deregulated lncRNAs (CTC-482H14.5, RP11-419K12.2, and RP11-736I24.4) associated with these processes.

CONCLUSION

The expression of various ncRNAs can influence the effect of AZA and new ncRNA-based predictive biomarkers can be defined.

Circular RNA circPHKA2 Relieves OGD-Induced Human Brain Microvascular Endothelial Cell Injuries through Competitively Binding miR-574-5p to Modulate SOD2

Background

Circular RNA phosphorylase kinase regulatory subunit alpha 2 (circPHKA2; hsa_circ_0090002) has a significantly, specifically different expression in acute ischemic stroke (AIS) patients' blood. Here, we intended to investigate the role and mechanism of circPHKA2 in oxygen-glucose deprivation- (OGD-) induced stoke model in human brain microvascular endothelial cells (HBMEC).

Methods

Expression of circPHKA2, microRNA- (miR-) 574-5p, and superoxide dismutase-2 (SOD2) was detected by quantitative PCR and western blotting. Cell injury was measured by detecting cell proliferation (EdU assay and CCK-8 assay), migration (transwell assay), neovascularization (tube formation assay), apoptosis (flow cytometry and western blotting), endoplasmic reticulum stress (western blotting), and oxidative stress (assay kits). Direct intermolecular interaction was determined by bioinformatics algorithms, dual-luciferase reporter assay, biotin-labelled miRNA capture, and argonaute 2 RNA immunoprecipitation.

Results

circPHKA2 was downregulated in AIS patients' blood in SOD2-correlated manner. Reexpressing circPHKA2 rescued EdU incorporation, cell viability and migration, tube formation, B cell lymphoma-2 (Bcl-2) expression, and SOD activity of OGD-induced HBMEC and alleviate apoptotic rate and levels of Bcl-2-associated protein (Bax), glucose-regulated protein 78 kD (GRP78), C/EBP-homologous protein (CHOP), caspase-12, reactive oxygen species (ROS), and malondialdehyde (MDA). Additionally, blocking SOD2 partially attenuated these roles of circPHKA2 overexpression. Molecularly, circPHKA2 upregulated SOD2 expression via interacting with miR-574-5p, and miR-574-5p could target SOD2. Similarly, allied to neurovascular protection of circPHKA2 was the downregulation of miR-574-5p.

Conclusion

circPHKA2 could protect HBMEC against OGD-induced cerebral stroke model via the miR-574-5p/SOD2 axis, suggesting circPHKA2 as a novel and promising candidate in ischemic brain injury.