Study of the in vitro modulation exerted by the antidepressant drug escitalopram on the expression of candidate microRNAs and their target genes

The role of ncRNAs in depression

Depressive disorders have a significant impact on public health, and depression have an unsatisfactory recurrence rate and are challenging to treat. Non-coding RNAs (ncRNAs) are RNAs that do not code protein, which have been shown to be crucial for transcriptional regulation. NcRNAs are important to the onset, progress and treatment of depression because they regulate various physiological functions. This makes them distinctively useful as biomarkers for diagnosing and tracking responses to therapy among individuals with depression. It is important to seek out and summarize the research findings on the impact of ncRNAs on depression since significant advancements have been made in this area recently. Hence, we methodically outlined the findings of published researches on ncRNAs and depression, focusing on microRNAs. Above all, this review aims to improve our understanding of ncRNAs and provide new insights of the diagnosis and treatment of depression.

The important role of miR-770 as a novel potential diagnostic and therapeutic target for human cancer and other diseases

MicroRNA-770 (miR-770) is an RNA gene, located on chromosome 14q32.2. It has important effects on the pathobiology of cancers and other human diseases. It is known to be a tumor suppressor in breast cancer, ovarian cancer, gastric cancer, non-small cell lung cancer, prostate cancer, and glioblastoma. In colorectal adenocarcinoma and oral squamous cell carcinoma, miR-770 is regarded as an oncogenic miRNA. In several disorders, miR-770 dysregulation has been recognized as a potential biomarker for disease diagnosis and prognosis. Dysregulation of miR-770 has also been demonstrated in non-malignant human disorders, including Alzheimer's disease, dilated cardiomyopathy, diabetic nephropathy, Hirschsprung's disease, osteoarthritis, silicosis, and type 2 diabetes mellitus. In the current review, we have obtained the miR-770 target genes, ontology, and related pathways. We have also provided a comprehensive review of miR-770 in both malignant and non-malignant disorders and explained its possible therapeutic implications.

Hippocampal microRNA-26a-3p deficit contributes to neuroinflammation and behavioral disorders via p38 MAPK signaling pathway in rats

BACKGROUND

Neuronal injury is considered a critical risk factor in the pathogenesis of most neurological and neuropsychiatric diseases. However, the underlying molecular mechanisms and identification of potential therapeutic targets for preventing neuronal injury associated with brain function remain largely uncharacterized. Therefore, identifying neural mechanisms would put new insights into the progression of this condition and provide novel therapeutic strategies for the treatment of these diseases.

METHODS

Stereotactic injection of AAV virus was used to knock-down the miR-26a-3p within hippocampus of rats. Behavioral changes was detected by open field test (OFT), elevated plus maze (EPM), forced swim test (FST) and sucrose preference test (SPT). The inflammatory cytokines and related proteins were verified by real-time quantitative PCR, immunoblotting or immunofluorescence assay. Golgi staining and electron microscopy analysis was used to observe the dendritic spine, synapse and ultrastructural pathology. SB203580 (0.5 mg/kg) were administered daily to prevent p38 MAPK via an intraperitoneal (i.p.) injection. Finally, electrophysiological method was used to examine the synaptic transmission via whole-cell patch-clamp recording.

RESULTS

Here, we showed that miR-26a-3p deficiency within hippocampal regions leads to the activation of microglia, increased level of pro-inflammatory cytokines and behavioral disorders in rats, effects which appear to be mediated by directly targeting the p38 mitogen-activated protein kinase (MAPK)-NF-κB signaling pathway. Specifically, we found that the enhanced glia-activation may consequently result in neuronal deterioration that mainly presented as the dysregulation of structural and functional plasticity in hippocampal neurons. In contrast, preventing p38 pathway by SB203580 significantly ameliorated abnormal behavioral phenotypes and neuronal jury resulting from miR-26a-3p knock-down.

CONCLUSION

These results suggest that the normal expression of miR-26a-3p exerts neuroprotective effects via suppressing neural abnormality and maintaining neuroplasticity to against behavioral disorders in rats. These effects appear to involve a down-regulation of p38 MAPK-NF-κB signaling within the hippocampal region. Taken together, these findings provide evidence that miR-26a-3p can function as a critical factor in regulating neural activity and suggest that the maintaining of normal structure and function of neurons might be a potential therapeutic strategy in the treatment of neurological disorders.

Drug repositioning: Using psychotropic drugs for the treatment of glioma

Psychotropic drugs can penetrate the blood-brain barrier and regulate the levels of neurotransmitters and neuromodulators such as γ-aminobutyric acid, glutamate, serotonin, dopamine, and norepinephrine in the brain, and thus influence neuronal activity. Neuronal activity in the tumor microenvironment can promote the growth and expansion of glioma. There is increasing evidence that in addition to their use in the treatment of mental disorders, antipsychotic, antidepressant, and mood-stabilizing drugs have clinical potential for cancer therapy. These drugs have been shown to inhibit the malignant progression of glioma by targeting signaling pathways related to cell proliferation, apoptosis, or invasion/migration or by increasing the sensitivity of glioma cells to conventional chemotherapy or radiotherapy. In this review, we summarize findings from preclinical and clinical studies investigating the use of antipsychotics, antidepressants, and mood stabilizers in the treatment of various types of cancer, with a focus on glioma; and discuss their presumed antitumor mechanisms. The existing evidence indicates that psychotropic drugs with established pharmacologic and safety profiles can be repurposed as anticancer agents, thus providing new options for the treatment of glioma.

The important roles of microRNAs in depression: new research progress and future prospects

MicroRNAs (miRNAs) are non-encoding, single-stranded RNA molecules of about 22 nucleotides in length encoded by endogenous genes involved in posttranscriptional gene expression regulation. Studies have shown that miRNAs participate in a series of important pathophysiological processes, including the pathogenesis of depression. This article systematically summarized the research results published in the field of miRNAs and depression, which mainly involved three topics: circulating miRNAs as markers for diagnosis and prognosis of depression, the regulatory roles of miRNAs in the pathogenesis of depression, and the roles of miRNAs in the mechanisms of depression treatment. By summarizing and analyzing the research literature in recent years, we found that some circulating miRNAs can be potential biomarkers for the diagnosis and prognostic evaluation of depression. miRNAs that disorderly expressed during the disease play important roles in the depression pathogenesis, and miRNAs also play roles in the mechanisms of psychotherapy and drug therapy for depression. Elucidating the important roles of miRNAs in depression will bring people's understanding of the pathogenesis of depression to a new level. In addition, these miRNAs may be developed as new biomarkers for diagnosing depression, or as drug targets, or these molecules may be used as new drugs, which may provide new means for the treatment of depression. KEY MESSAGES: • The research results of miRNAs and depression are reviewed. • Circulating miRNAs can be potential biomarkers for depression. • MiRNAs play important roles in the depression pathogenesis. • MiRNAs play important roles in drug therapy for depression.

miRNAs in depression vulnerability and resilience: novel targets for preventive strategies

The exposure to stressful experiences during the prenatal period and through the first years of life is known to affect the brain developmental trajectories, leading to an enhanced vulnerability for the development of several psychiatric disorders later in life. However, not all the subjects exposed to the same stressful experience develop a pathologic condition, as some of them, activating coping strategies, become more resilient. The disclosure of mechanisms associated with stress vulnerability or resilience may allow the identification of novel biological processes and potential molecules that, if properly targeted, may prevent susceptibility or potentiate resilience. Over the last years, miRNAs have been proposed as one of the epigenetic mechanisms mediating the long-lasting effects of stress. Accordingly, they are associated with the development of stress vulnerability or resilience-related strategies. Moreover, miRNAs have been proposed as possible biomarkers able to identify subjects at high risk to develop depression and to predict the response to pharmacological treatments. In this review, we aimed to provide an overview of findings from studies in rodents and humans focused on the involvement of miRNAs in the mechanisms of stress response with the final goal to identify distinct sets of miRNAs involved in stress vulnerability or resilience. In addition, we reviewed studies on alterations of miRNAs in the context of depression, showing data on the involvement of miRNAs in the pathogenesis of the disease and in the efficacy of pharmacological treatments, discussing the potential utility of miRNAs as peripheral biomarkers able to predict the treatment response.