A cAMP-response element binding protein-induced microRNA regulates neuronal morphogenesis

Elucidating the molecular symphony: unweaving the transcriptional & epigenetic pathways underlying neuroplasticity in opioid dependence and withdrawal

The persistent use of opioids leads to profound changes in neuroplasticity of the brain, contributing to the emergence and persistence of addiction. However, chronic opioid use disrupts the delicate balance of the reward system in the brain, leading to neuroadaptations that underlie addiction. Chronic cocaine usage leads to synchronized alterations in gene expression, causing modifications in the Nucleus Accumbens (NAc), a vital part of the reward system of the brain. These modifications assist in the development of maladaptive behaviors that resemble addiction. Neuroplasticity in the context of addiction involves changes in synaptic connectivity, neuronal morphology, and molecular signaling pathways. Drug-evoked neuroplasticity in opioid addiction and withdrawal represents a complicated interaction between environmental, genetic, and epigenetic factors. Identifying specific transcriptional and epigenetic targets that can be modulated to restore normal neuroplasticity without disrupting essential physiological processes is a critical consideration. The discussion in this article focuses on the transcriptional aspects of drug-evoked neuroplasticity, emphasizing the role of key transcription factors, including cAMP response element-binding protein (CREB), ΔFosB, NF-kB, Myocyte-enhancing factor 2 (MEF2), Methyl-CpG binding protein 2 (MeCP2), E2F3a, and FOXO3a. These factors regulate gene expression and lead to the neuroadaptive changes observed in addiction and withdrawal. Epigenetic regulation, which involves modifying gene accessibility by controlling these structures, has been identified as a critical component of addiction development. By unraveling these complex molecular processes, this study provides valuable insights that may pave the way for future therapeutic interventions targeting the mechanisms underlying addiction and withdrawal.

Cognitive Dysfunction and Exercise: From Epigenetic to Genetic Molecular Mechanisms

Maintaining good health is crucial, and exercise plays a vital role in achieving this goal. It offers a range of positive benefits for cognitive function, regardless of age. However, as our population ages and life expectancy increases, cognitive impairment has become a prevalent issue, often coexisting with age-related neurodegenerative conditions. This can result in devastating consequences such as memory loss, difficulty speaking, and confusion, greatly hindering one's ability to lead an ordinary life. In addition, the decrease in mental capacity has a significant effect on an individual's physical and emotional well-being, greatly reducing their overall level of contentment and causing a significant financial burden for communities. While most current approaches aim to slow the decline of cognition, exercise offers a non-pharmacological, safe, and accessible solution. Its effects on cognition are intricate and involve changes in the brain's neural plasticity, mitochondrial stability, and energy metabolism. Moreover, exercise triggers the release of cytokines, playing a significant role in the body-brain connection and its impact on cognition. Additionally, exercise can influence gene expression through epigenetic mechanisms, leading to lasting improvements in brain function and behavior. Herein, we summarized various genetic and epigenetic mechanisms that can be modulated by exercise in cognitive dysfunction.

Identifying the differentially expressed peripheral blood microRNAs in psychiatric disorders: a systematic review and meta-analysis

Background

Evidence has suggested that microRNAs (miRNAs) may play an important role in the pathogenesis of psychiatric disorders (PDs), but the results remain inconclusive. We aimed to identify specific differentially expressed miRNAs and their overlapping miRNA expression profiles in schizophrenia (SZ), major depression disorder (MDD), and bipolar disorder (BD), the three major PDs.

Methods

The literatures up to September 30, 2023 related to peripheral blood miRNAs and PDs were searched and screened from multiple databases. The differences in miRNA levels between groups were illustrated by the standardized mean difference (SMD) and 95% confidence interval (95% CI).

Results

In total, 30 peripheral blood miRNAs were included in the meta-analysis, including 16 for SZ, 12 for MDD, and 2 for BD, each was reported in more than 3 independent studies. Compared with the control group, miR-181b-5p, miR-34a-5p, miR-195-5p, miR-30e-5p, miR-7-5p, miR-132-3p, miR-212-3p, miR-206, miR-92a-3p and miR-137-3p were upregulated in SZ, while miR-134-5p, miR-107 and miR-99b-5p were downregulated. In MDD, miR-124-3p, miR-132-3p, miR-139-5p, miR-182-5p, miR-221-3p, miR-34a-5p and miR-93-5p were upregulated, while miR-144-5p and miR-135a-5p were downregulated. However, we failed to identify statistically differentially expressed miRNAs in BD. Interestingly, miR-132-3p and miR-34a-5p were upregulated in both SZ and MDD.

Conclusions

Our study identified 13 differentially expressed miRNAs in SZ and 9 in MDD, among which miR-132-3p and miR-34a-5p were upregulated in both SZ and MDD by systematically analyzing qualified studies. These miRNAs may be used as potential biomarkers for the diagnosis of SZ and MDD in the future.

Systematic Review Registration

http://www.crd.york.ac.uk/PROSPERO, identifier CRD42023486982.

miR-153 promotes neural differentiation by activating the cell adhesion/Ca2+ signaling pathway and targeting ion channel activity in HT-22 cells by bioinformatic analysis

MicroRNAs have been studied extensively in neurodegenerative diseases. In a previous study, miR-153 promoted neural differentiation and projection formation in mouse hippocampal HT-22 cells. However, the pathways and molecular mechanism underlying miR-153-induced neural differentiation remain unclear. To explore the molecular mechanism of miR-153 on neural differentiation, we performed RNA sequencing on miR-153-overexpressed HT-22 cells. Based on RNA sequencing, differentially expressed genes (DEGs) and pathways in miR-153-overexpressed cells were identified. The Database for Annotation, Visualization and Integrated Discovery and Gene Set Enrichment Analysis were used to perform functional annotation and enrichment analysis of DEGs. Targetscan predicted the targets of miR-153. The Search Tool for the Retrieval of Interacting Genes and Cytoscape, were used to construct protein-protein interaction networks and identify hub genes. Q-PCR was used to detect mRNA expression of the identified genes. The expression profiles of the identified genes were compared between embryonic days 9.5 (E9.5) and E11.5 in the embryotic mouse brain of the GDS3442 dataset. Cell Counting Kit-8 assay was used to determine cell proliferation and cellular susceptibility to amyloid β-protein (Aβ) toxicity in miR-153-overexpressed cells. The results indicated that miR-153 increased cell adhesion/Ca2+ (Cdh5, Nrcam, and P2rx4) and Bdnf/Ntrk2 neurotrophic signaling pathway, and decreased ion channel activity (Kcnc3, Kcna4, Clcn5, and Scn5a). The changes in the expression of the identified genes in miR-153-overexpressed cells were consistent with the expression profile of GDS3442 during neural differentiation. In addition, miR-153 overexpression decreased cellular susceptibility to Aβ toxicity in HT-22 cells. In conclusion, miR-153 overexpression may promote neural differentiation by inducing cell adhesion and the Bdnf/Ntrk2 pathway, and regulating electrophysiological maturity by targeting ion channels. MiR-153 may play an important role in neural differentiation; the findings provide a useful therapeutic direction for neurodegenerative diseases.

Bright daylight produces negative effects on affective and cognitive outcomes in nocturnal rats

The daily light/dark cycle affects animals' learning, memory, and cognition. Exposure to insufficient daylight illumination negatively impacts emotion and cognition, leading to seasonal affective disorder characterized by depression, anxiety, low motivation, and cognitive impairment in diurnal animals. However, how this affects memory, learning, and cognition in nocturnal rodents is largely unknown. Here, we studied the effect of daytime light illuminance on memory, learning, cognition, and expression of mRNA levels in the hippocampus, thalamus, and cortex, the higher-order learning centers. Two experiments were performed. In experiment one, rats were exposed to 12 L:12D (12 h light and 12 h dark) with a 10, 100, or 1000 lx daytime light illuminance. After 30 days, various behavioral tests (novel object recognition test, hole board test, elevated plus maze test, radial arm maze, and passive avoidance test) were performed. In experiment 2, rats since birth were raised either under constant bright light (250 lx; LL) or a daily light-dark cycle (12 L:12D). After four months, behavioral tests (novel object recognition test, hole board test, elevated plus maze test, radial arm maze, passive avoidance test, Morris water maze, and Y-maze tests) were performed. At the end of experiments, rats were sampled, and mRNA expression of Brain-Derived Neurotrophic Factor (Bdnf), Tyrosine kinase (Trk), microRNA132 (miR132), Neurogranin (Ng), Growth Associated Protein 43 (Gap-43), cAMP Response Element-Binding Protein (Crebp), Glycogen synthase kinase-3β (Gsk3β), and Tumour necrosis factor-α (Tnf-α) were measured in the hippocampus, cortex, and thalamus of individual rats. Our results show that exposure to bright daylight (100 and 1000 lx; experiment 1) or constant light (experiment 2) compromises memory, learning, and cognition. Suppressed expression levels of these mRNA were also observed in the hypothalamus, cortex, and thalamus. These results suggest that light affects differently to different groups of animals.

Understanding the multifaceted role of miRNAs in Alzheimer's disease pathology

Small non-coding RNAs (miRNAs) regulate gene expression by binding to mRNA and mediating its degradation or inhibiting translation. Since miRNAs can regulate the expression of several genes, they have multiple roles to play in biological processes and human diseases. The majority of miRNAs are known to be expressed in the brain and are involved in synaptic functions, thus marking their presence and role in major neurodegenerative disorders, including Alzheimer's disease (AD). In AD, amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) are known to be the major hallmarks. The clearance of Aβ and tau is known to be associated with miRNA dysregulation. In addition, the β-site APP cleaving enzyme (BACE 1), which cleaves APP to form Aβ, is also found to be regulated by miRNAs, thus directly affecting Aβ accumulation. Growing evidences suggest that neuroinflammation can be an initial event in AD pathology, and miRNAs have been linked with the regulation of neuroinflammation. Inflammatory disorders have also been associated with AD pathology, and exosomes associated with miRNAs are known to regulate brain inflammation, suggesting for the role of systemic miRNAs in AD pathology. Several miRNAs have been related in AD, years before the clinical symptoms appear, most of which are associated with regulating the cell cycle, immune system, stress responses, cellular senescence, nerve growth factor (NGF) signaling, and synaptic regulation. Phytochemicals, especially polyphenols, alter the expression of various miRNAs by binding to miRNAs or binding to the transcriptional activators of miRNAs, thus control/alter various metabolic pathways. Awing to the sundry biological processes being regulated by miRNAs in the brain and regulation of expression of miRNAs via phytochemicals, miRNAs and the regulatory bioactive phytochemicals can serve as therapeutic agents in the treatment and management of AD.

Mechanisms of microRNA-132 in central neurodegenerative diseases: A comprehensive review

MicroRNA-132 (miR-132) is a highly conserved molecule that plays a crucial regulatory role in central nervous system (CNS) disorders. The expression levels of miR-132 exhibit variability in various neurological disorders and have been closely linked to disease onset and progression. The expression level of miR-132 in the CNS is regulated by a diverse range of stimuli and signaling pathways, including neuronal migration and integration, dendritic outgrowth, and complexity, synaptogenesis, synaptic plasticity, as well as inflammation and apoptosis activation. The aberrant expression of miR-132 in various central neurodegenerative diseases has garnered widespread attention. Clinical studies have revealed altered miR-132 expression levels in both chronic and acute CNS diseases, positioning miR-132 as a potential biomarker or therapeutic target. An in-depth exploration of miR-132 holds the promise of enhancing our understanding of the mechanisms underlying CNS diseases, thereby offering novel insights and strategies for disease diagnosis and treatment. It is anticipated that this review will assist researchers in recognizing the potential value of miR-132 and in generating innovative ideas for clinical trials related to CNS degenerative diseases.

The role of microRNAs in the pathophysiology of human central nervous system: A focus on neurodegenerative diseases

microRNAs (miRNAs) are suggested to play substantial roles in regulating the development and various physiologic functions of the central nervous system (CNS). These include neurogenesis, cell fate and differentiation, morphogenesis, formation of dendrites, and targeting non-neural mRNAs. Notably, deregulation of an increasing number of miRNAs is associated with several neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis and CNS tumors. They are particularly known to affect the amyloid β (Aβ) cleavage and accumulation, tau protein homeostasis, and expression of alpha-synuclein (α-syn), Parkin, PINK1, and brain-derived neurotrophic factor (BDNF) that play pivotal roles in the pathogenesis of neurodegenerative diseases. These include miR-16, miR-17-5p, miR-20a, miR-106a, miR-106b, miR-15a, miR-15b, miR-103, miR-107, miR-298, miR-328, miR-195, miR-485, and miR-29. In CNS tumors, several miRNAs, including miR-31, miR-16, and miR-21 have been identified to modulate tumorigenesis through impacting tumor invasion and apoptosis. In this review article, we have a look at the recent advances on our knowledge about the role of miRNAs in human brain development and functions, neurodegenerative diseases, and their clinical potentials.

Small molecule regulators of microRNAs identified by high-throughput screen coupled with high-throughput sequencing

MicroRNAs (miRNAs) regulate fundamental biological processes by silencing mRNA targets and are dysregulated in many diseases. Therefore, miRNA replacement or inhibition can be harnessed as potential therapeutics. However, existing strategies for miRNA modulation using oligonucleotides and gene therapies are challenging, especially for neurological diseases, and none have yet gained clinical approval. We explore a different approach by screening a biodiverse library of small molecule compounds for their ability to modulate hundreds of miRNAs in human induced pluripotent stem cell-derived neurons. We demonstrate the utility of the screen by identifying cardiac glycosides as potent inducers of miR-132, a key neuroprotective miRNA downregulated in Alzheimer's disease and other tauopathies. Coordinately, cardiac glycosides downregulate known miR-132 targets, including Tau, and protect rodent and human neurons against various toxic insults. More generally, our dataset of 1370 drug-like compounds and their effects on the miRNome provides a valuable resource for further miRNA-based drug discovery.

How dendritic spines shape is determined by MMP-9 activity in FXS

Matrix metalloproteinase-9 (MMP-9) belongs to the family of endopeptidases expressed in neurons and secreted at the synapse in response to neuronal activity. It regulates the pericellular environment by cleaving its protein components. MMP9 is involved in activity-dependent reorganization of spine architecture. In the mouse model of fragile X syndrome (FXS), the most common inherited intellectual disability and the most common single-gene cause of autism, increased synaptic expression of MMP-9 is responsible for the observed dendritic spine abnormalities. In this chapter, I summarize the current data on the molecular regulatory pathways responsible for synaptic MMP-9 expression and discuss the fact that MMP-9 is extracellularly localized, making it a particularly attractive potential target for therapeutic pharmacological intervention in FXS.

Addictive drugs modify neurogenesis, synaptogenesis and synaptic plasticity to impair memory formation through neurotransmitter imbalances and signaling dysfunction

Drug abuse changes neurophysiological functions at multiple cellular and molecular levels in the addicted brain. Well-supported scientific evidence suggests that drugs negatively affect memory formation, decision-making and inhibition, and emotional and cognitive behaviors. The mesocorticolimbic brain regions are involved in reward-related learning and habitual drug-seeking/taking behaviors to develop physiological and psychological dependence on the drugs. This review highlights the importance of specific drug-induced chemical imbalances resulting in memory impairment through various neurotransmitter receptor-mediated signaling pathways. The mesocorticolimbic modifications in the expression levels of brain-derived neurotrophic factor (BDNF) and the cAMP-response element binding protein (CREB) impair reward-related memory formation following drug abuse. The contributions of protein kinases and microRNAs (miRNAs), along with the transcriptional and epigenetic regulation have also been considered in memory impairment underlying drug addiction. Overall, we integrate the research on various types of drug-induced memory impairment in distinguished brain regions and provide a comprehensive review with clinical implications addressing the upcoming studies.

Discerning the Prospects of miRNAs as a Multi-Target Therapeutic and Diagnostic for Alzheimer's Disease

Although over the last few decades, numerous attempts have been made to halt Alzheimer's disease (AD) progression and mitigate its symptoms, only a few have been proven beneficial. Most medications available, still only cater to the symptoms of the disease rather than fixing the cause at the root level. A novel approach involving the use of miRNAs, which work on the principle of gene silencing, is being explored by scientists. Naturally present miRNAs in the biological system help to regulate various genes than may be implicated in AD-like BACE-1 and APP. One miRNA thus, holds the power to keep a check on several genes, conferring it the ability to be used as a multi-target therapeutic. With aging and the onset of diseased pathology, dysregulation of these miRNAs is observed. This flawed miRNA expression is responsible for the unusual buildup of amyloid proteins, fibrillation of tau proteins in the brain, neuronal death and other hallmarks leading to AD. The use of miRNA mimics and miRNA inhibitors provides an attractive perspective for fixing the upregulation and downregulation of miRNAs that led to abnormal cellular activities. Furthermore, the detection of miRNAs in the CSF and serum of diseased patients might be considered an earlier biomarker for the disease. While most of the therapies designed around AD have not succeeded completely, the targeting of dysregulated miRNAs in AD patients might give a new direction to scholars to develop an effective treatment for Alzheimer's disease.

Light at night: effect on the daily clock, learning, memory, cognition, and expression of transcripts in different brain regions of rat

The rapid increase in urbanization is altering the natural composition of the day-night light ratio. The light/dark cycle regulates animal learning, memory, and mood swings. A study was conducted to examine the effect of different quantity and quality of light at night on the daily clock, learning, memory, cognition, and expression of transcripts in key learning centers. Treatment was similar for experiments one to three. Rats were exposed for 30 days to 12 h light and 12 h dark with a night light of 2 lx (dLAN group), 250 lx (LL), or without night light (LD). In experiment one, after 28 days, blood samples were collected and 2 days later, animals were exposed to constant darkness. In experiment two, after 30 days of treatment, animals were subjected to various tests involving learning, memory, and cognition. In experiment three, after 30 days of treatment, animals were sampled, and transcript levels of brain-derived neurotrophic factor, tyrosine kinase, Growth-Associated Protein 43, Neurogranin, microRNA-132, cAMP Response Element-Binding Protein, Glycogen synthase kinase-3β, and Tumor necrosis factor α were measured in hippocampus, thalamus, and cortex tissues. In experiment four, animals were exposed to night light of 0.019 W/m2 but of either red (640 nm), green (540 nm), or blue (450 nm) wavelength for 30 days, and similar tests were performed as mentioned in experiment 2. While in experiment five, after 30 days of respective wavelength treatments, all animals were sampled for gene expression studies. Our results show that exposure to dLAN and LL affects the daily clock as reflected by altered melatonin secretion and locomotor activity, compromises the learning, memory, and cognitive ability, and alterations in the expression levels of transcripts in the hypothalamus, cortex, and thalamus. The effect is night light intensity dependent. Further, blue light at night has less drastic effects than green and red light. These results could be of the potential use of framing the policies for the use of light at night.

Impaired BCAA catabolism in adipose tissues promotes age-associated metabolic derangement

Adipose tissues are central in controlling metabolic homeostasis and failure in their preservation is associated with age-related metabolic disorders. The exact role of mature adipocytes in this phenomenon remains elusive. Here we describe the role of adipose branched-chain amino acid (BCAA) catabolism in this process. We found that adipocyte-specific Crtc2 knockout protected mice from age-associated metabolic decline. Multiomics analysis revealed that BCAA catabolism was impaired in aged visceral adipose tissues, leading to the activation of mechanistic target of rapamycin complex (mTORC1) signaling and the resultant cellular senescence, which was restored by Crtc2 knockout in adipocytes. Using single-cell RNA sequencing analysis, we found that age-associated decline in adipogenic potential of visceral adipose tissues was reinstated by Crtc2 knockout, via the reduction of BCAA-mTORC1 senescence-associated secretory phenotype axis. Collectively, we propose that perturbation of BCAA catabolism by CRTC2 is critical in instigating age-associated remodeling of adipose tissue and the resultant metabolic decline in vivo.

The Pleiotropic Face of CREB Family Transcription Factors

cAMP responsive element-binding protein (CREB) is one of the most intensively studied phosphorylation-dependent transcription factors that provide evolutionarily conserved mechanisms of differential gene expression in vertebrates and invertebrates. Many cellular protein kinases that function downstream of distinct cell surface receptors are responsible for the activation of CREB. Upon functional dimerization of the activated CREB to cis-acting cAMP responsive elements within the promoters of target genes, it facilitates signal-dependent gene expression. From the discovery of CREB, which is ubiquitously expressed, it has been proven to be involved in a variety of cellular processes that include cell proliferation, adaptation, survival, differentiation, and physiology, through the control of target gene expression. In this review, we highlight the essential roles of CREB proteins in the nervous system, the immune system, cancer development, hepatic physiology, and cardiovascular function and further discuss a wide range of CREB-associated diseases and molecular mechanisms underlying the pathogenesis of these diseases.

Spotlight on the Expanding Role of miR-647 in Human Cancers

MicroRNAs are a large group of small, non-coding ssRNAs (miRNAs) that have an epigenetically pivotal role in gene expression and other biological processes in cells and can be regarded as capable biomarkers for the early detection and management of cancer. The aim of the present review article is to summarize the evidence for recognizing the molecular mechanism, target genes, and clinical significance of miR-647 in different cancers. Multiple studies have demonstrated that aberrant expression of miR-647 could be found in a variety of malignancies, such as bladder cancer, cervical cancer, colorectal cancer, gastric cancer, glioma, hepatocellular carcinoma, non-small cell lung cancer, ovarian cancer, and prostate cancer have reported, notably, increase or decrease in expression of miR-647 so that it can function as a tumorigenic (oncomiR) or tumor suppressor gene. MiR-647 is effective in the proliferation, migration, and invasion of cancer cells by playing a function in cell cycle pathways. MiR-647 can be a valuable potential biomarker for assessing the extent of cancer, prognosis, and response to therapy and shows great therapeutic efficacy in different solid tumors. Moreover, serum concentrations of miR-647 are directly effective in decreasing overall survival and disease progression. So, an efficient therapeutic target can be the effect on miR-647 expression by antitumor drugs.

Endocrine-Disrupting Chemicals and Hippocampal Development: The Role of Estrogen and Androgen Signaling

Hormones are important regulators of key processes during fetal brain development. Thus, the developing brain is vulnerable to the action of chemicals that can interfere with endocrine signals. Epidemiological studies have pointed toward sexually dimorphic associations between neurodevelopmental outcomes, such as cognitive abilities, in children and prenatal exposure to endocrine-disrupting chemicals (EDCs). This points toward disruption of sex steroid signaling in the development of neural structures underlying cognitive functions, such as the hippocampus, an essential mediator of learning and memory processes. Indeed, during development, the hippocampus is subjected to the organizational effects of estrogens and androgens, which influence hippocampal cell proliferation, differentiation, dendritic growth, and synaptogenesis in the hippocampal fields of Cornu Ammonis and the dentate gyrus. These early organizational effects correlate with a sexual dimorphism in spatial cognition and are subject to exogenous chemical perturbations. This review summarizes the current knowledge about the organizational effects of estrogens and androgens on the developing hippocampus and the evidence for hippocampal-dependent learning and memory perturbations induced by developmental exposure to EDCs. We conclude that, while it is clear that sex hormone signaling plays a significant role during hippocampal development, a complete picture at the molecular and cellular levels would be needed to establish causative links between the endocrine modes of action exerted by EDCs and the adverse outcomes these chemicals can induce at the organism level.

microRNA-132 regulates gene expression programs involved in microglial homeostasis

microRNA-132 (miR-132), a known neuronal regulator, is one of the most robustly downregulated microRNAs (miRNAs) in the brain of Alzheimer's disease (AD) patients. Increasing miR-132 in AD mouse brain ameliorates amyloid and Tau pathologies, and also restores adult hippocampal neurogenesis and memory deficits. However, the functional pleiotropy of miRNAs requires in-depth analysis of the effects of miR-132 supplementation before it can be moved forward for AD therapy. We employ here miR-132 loss- and gain-of-function approaches using single-cell transcriptomics, proteomics, and in silico AGO-CLIP datasets to identify molecular pathways targeted by miR-132 in mouse hippocampus. We find that miR-132 modulation significantly affects the transition of microglia from a disease-associated to a homeostatic cell state. We confirm the regulatory role of miR-132 in shifting microglial cell states using human microglial cultures derived from induced pluripotent stem cells.

Non-coding RNA in the wiring and remodeling of neural circuits

The brain constantly adapts to changes in the environment, a capability that underlies memory and behavior. Long-term adaptations require the remodeling of neural circuits that are mediated by activity-dependent alterations in gene expression. Over the last two decades, it has been shown that the expression of protein-coding genes is significantly regulated by a complex layer of non-coding RNA (ncRNA) interactions. The aim of this review is to summarize recent discoveries regarding the functional involvement of ncRNAs during different stages of neural circuit development, activity-dependent circuit remodeling, and circuit maladapations underlying neurological and neuropsychiatric disorders. In addition to the intensively studied microRNA (miRNA) family, we focus on more recently added ncRNA classes, such as long ncRNAs (lncRNAs) and circular RNAs (circRNAs), and discuss the complex regulatory interactions between these different RNAs. We conclude by discussing the potential relevance of ncRNAs for cell-type and -state-specific regulation in the context of memory formation, the evolution of human cognitive abilities, and the development of new diagnostic and therapeutic tools in brain disorders.

A Comprehensive Study on Signal Transduction and Therapeutic Role of miR-877 in Human Cancers

MicroRNAs are a group of short non-coding RNAs (miRNAs), which are epigenetically involved in gene expression and other cellular biological processes and can be considered as potential biomarkers for cancer detection and support for treatment management. This review aims to amass the evidence in order to reach the molecular mechanism and clinical significance of miR-877 in different types of cancer. Dysregulation of miR-877 level in various types of malignancies as bladder cancer, cervical cancer, cholangiocarcinoma, colorectal cancer (CRC), gastric cancer, glioblastoma, head and neck squamous cell carcinoma (HNSCC), hepatocellular carcinoma, laryngeal squamous cell carcinoma, melanoma, non-small cell lung cancer (NSCLC), oral squamous cell carcinoma, ovarian cancer (OC), pancreatic ductal adenocarcinoma, and renal cell carcinoma (RCC) have reported, significantly increase or decrease in its level, which can be indicated to its function as oncogene or tumor suppressor. MiR-877 is involved in cell proliferation, migration, and invasion through cell cycle pathways in cancer. MiR-877 could be potential a candidate as a valuable biomarker for prognosis in various cancers. Through this study, we proposed that miR-877 can potentially be a candidate as a prognostic marker for early detection of tumor development, progression, as well as metastasis.

Role of Hippocampal miR-132-3p in Modifying the Function of Protein Phosphatase Mg2+/Mn2+-dependent 1 F in Depression

Depression is a common, severe, and debilitating psychiatric disorder of unclear etiology. Our previous study has shown that protein phosphatase Mg2+/Mn2+-dependent 1F (PPM1F) in the hippocampal dentate gyrus (DG) displays significant regulatory effects in depression-related behaviors. miR-132-3p plays a potential role in the etiology of depression. This study explored the effect of miR-132-3p on the onset of depression and the possible underlying mechanism for modulating PPM1F expression during the pathology of depression. We found that miR-132-3p levels in the hippocampus of depressed mice subjected to chronic unpredictable stress (CUS) were dramatically reduced, which were correlated with depression-related behaviors. Knockdown of miR-132-3p in hippocampal DG resulted in depression-related phenotypes and increased susceptibility to stress. miR-132-3p overexpression in hippocampal DG alleviated CUS-induced depression-related performance. We then screened out the potential target genes of miR-132-3p, and we found that the expression profiles of sterol regulatory element-binding transcription factor 1 (Srebf1) and forkhead box protein O3a (FOXO3a) were positively correlated with PPM1F under the condition of miR-132-3p knockdown. Finally, as anticipated, we revealed that the activities of Ca2+/calmodulin-dependent protein kinase II (CAMKII) and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) were reduced, which underlies the target signaling pathway of PPM1F. In conclusion, our study suggests that miR-132-3p was designed to regulate depression-related behaviors by indirectly regulating PPM1F and targeting Srebf1 and FOXO3a, which have been linked to the pathogenesis and treatment of depression.

MicroRNA Profiling of Self-Renewing Human Neural Stem Cells Reveals Novel Sets of Differentially Expressed microRNAs During Neural Differentiation In Vitro

The involvement of microRNAs (miRNAs) in orchestrating self-renewal and differentiation of stem cells has been revealed in a number of recent studies. And while in human pluripotent stem cells, miRNAs have been directly linked to the core pluripotency network, including the cell cycle regulation and the maintenance of the self-renewing capacity, their role in the onset of differentiation in other contexts, such as determination of neural cell fate, remains poorly described. To bridge this gap, we used three model cell types to study miRNA expression patterns: human embryonic stem cells (hESCs), hESCs-derived self-renewing neural stem cells (NSCs), and differentiating NSCs. The comprehensive miRNA profiling presented here reveals novel sets of miRNAs differentially expressed during human neural cell fate determination in vitro. Furthermore, we report a miRNA expression profile of self-renewing human NSCs, which has been lacking to this date. Our data also indicates that miRNA clusters enriched in NSCs share the target-determining seed sequence with cell cycle regulatory miRNAs expressed in pluripotent hESCs. Lastly, our mechanistic experiments confirmed that cluster miR-17-92, one of the NSCs-enriched clusters, is directly transcriptionally regulated by transcription factor c-MYC.

Small Molecule Regulators of microRNAs Identified by High-Throughput Screen Coupled with High-Throughput Sequencing

MicroRNAs (miRNAs) regulate fundamental biological processes by silencing mRNA targets and are dysregulated in many diseases. Therefore, miRNA replacement or inhibition can be harnessed as potential therapeutics. However, existing strategies for miRNA modulation using oligonucleotides and gene therapies are challenging, especially for neurological diseases, and none have yet gained clinical approval. We explore a different approach by screening a biodiverse library of small molecule compounds for their ability to modulate hundreds of miRNAs in human induced pluripotent stem cell-derived neurons. We demonstrate the utility of the screen by identifying cardiac glycosides as potent inducers of miR-132, a key miRNA downregulated in Alzheimer's disease and other tauopathies. Coordinately, cardiac glycosides downregulate known miR-132 targets, including Tau, and protect rodent and human neurons against various toxic insults. More generally, our dataset of 1370 drug-like compounds and their effects on the miRNome provide a valuable resource for further miRNA-based drug discovery.

Neuronal extracellular vesicles and associated microRNAs induce circuit connectivity downstream BDNF

Extracellular vesicles (EVs) have emerged as mediators of cellular communication, in part via the delivery of associated microRNAs (miRNAs), small non-coding RNAs that regulate gene expression. We show that brain-derived neurotrophic factor (BDNF) mediates the sorting of miR-132-5p, miR-218-5p, and miR-690 in neuron-derived EVs. BDNF-induced EVs in turn increase excitatory synapse formation in recipient hippocampal neurons, which is dependent on the inter-neuronal delivery of these miRNAs. Transcriptomic analysis further indicates the differential expression of developmental and synaptogenesis-related genes by BDNF-induced EVs, many of which are predicted targets of miR-132-5p, miR-218-5p, and miR-690. Furthermore, BDNF-induced EVs up-regulate synaptic vesicle (SV) clustering in a transmissible manner, thereby increasing synaptic transmission and synchronous neuronal activity. As BDNF and EV-miRNAs miR-218 and miR-132 were previously implicated in neuropsychiatric disorders such as anxiety and depression, our results contribute to a better understanding of disorders characterized by aberrant neural circuit connectivity.

Discovery and Validation of Circulating microRNAs as Biomarkers for Epileptogenesis after Experimental Traumatic Brain Injury-The EPITARGET Cohort

Traumatic brain injury (TBI) causes 10-20% of structural epilepsies and 5% of all epilepsies. The lack of prognostic biomarkers for post-traumatic epilepsy (PTE) is a major obstacle to the development of anti-epileptogenic treatments. Previous studies revealed TBI-induced alterations in blood microRNA (miRNA) levels, and patients with epilepsy exhibit dysregulation of blood miRNAs. We hypothesized that acutely altered plasma miRNAs could serve as prognostic biomarkers for brain damage severity and the development of PTE. To investigate this, epileptogenesis was induced in adult male Sprague Dawley rats by lateral fluid-percussion-induced TBI. Epilepsy was defined as the occurrence of at least one unprovoked seizure during continuous 1-month video-electroencephalography monitoring in the sixth post-TBI month. Cortical pathology was analyzed by magnetic resonance imaging on day 2 (D2), D7, and D21, and by histology 6 months post-TBI. Small RNA sequencing was performed from tail-vein plasma samples on D2 and D9 after TBI (n = 16, 7 with and 9 without epilepsy) or sham operation (n = 4). The most promising miRNA biomarker candidates were validated by droplet digital polymerase chain reaction in a validation cohort of 115 rats (8 naïve, 17 sham, and 90 TBI rats [21 with epilepsy]). These included 7 brain-enriched plasma miRNAs (miR-434-3p, miR-9a-3p, miR-136-3p, miR-323-3p, miR-124-3p, miR-212-3p, and miR-132-3p) that were upregulated on D2 post-TBI (p < 0.001 for all compared with naïve rats). The acute post-TBI plasma miRNA profile did not predict the subsequent development of PTE or PTE severity. Plasma miRNA levels, however, predicted the cortical pathology severity on D2 (Spearman ρ = 0.345-0.582, p < 0.001), D9 (ρ = 0.287-0.522, p < 0.001-0.01), D21 (ρ = 0.269-0.581, p < 0.001-0.05) and at 6 months post-TBI (ρ = 0.230-0.433, p < 0.001-0.05). We found that the levels of 6 of 7 miRNAs also reflected mild brain injury caused by the craniotomy during sham operation (ROC AUC 0.76-0.96, p < 0.001-0.05). In conclusion, our findings revealed that increased levels of neuronally enriched miRNAs in the blood circulation after TBI reflect the extent of cortical injury in the brain but do not predict PTE development.

Regulation by noncoding RNAs of local translation, injury responses, and pain in the peripheral nervous system

Neuropathic pain is a chronic condition arising from damage to somatosensory pathways that results in pathological hypersensitivity. Persistent pain can be viewed as a consequence of maladaptive plasticity which, like most enduring forms of cellular plasticity, requires altered expression of specific gene programs. Control of gene expression at the level of protein synthesis is broadly utilized to directly modulate changes in activity and responsiveness in nociceptive pathways and provides an effective mechanism for compartmentalized regulation of the proteome in peripheral nerves through local translation. Levels of noncoding RNAs (ncRNAs) are commonly impacted by peripheral nerve injury leading to persistent pain. NcRNAs exert spatiotemporal regulation of local proteomes and affect signaling cascades supporting altered sensory responses that contribute to hyperalgesia. This review discusses ncRNAs found in the peripheral nervous system (PNS) that are dysregulated following nerve injury and the current understanding of their roles in pathophysiological pain-related responses including neuroimmune interactions, neuronal survival and axon regeneration, Schwann cell dedifferentiation and proliferation, intercellular communication, and the generation of ectopic action potentials in primary afferents. We review progress in the field beyond cataloging, with a focus on the relevant target transcripts and mechanisms underlying pain modulation by ncRNAs.

Role of miRNAs interference on ovarian functions and premature ovarian failure

Premature ovarian failure is a to some extent unknown and intricate problem with diverse causes and clinical manifestations. The lack of ovarian sex hormones presumably is effective in the occurrence of ovarian failure. Our progress in this field has been very little despite undertaken scientific research endeavors; scholars still are trying to understand the explanation of this dilemmatic medical condition. In contrast, the practice of clinical medicine has made meaningful strides in providing assurance to the women with premature ovarian insufficiency that their quality of life as well as long-term health can be optimized through timely intervention. Very recently Scientists have investigated the regulating effects of small RNA molecules on steroidogenesis apoptosis, ovulation, gonadal, and corpus luteum development of ovaries. In this literature review, we tried to talk over the mechanisms of miRNAs in regulating gene expression after transcription in the ovary. Video abstract.

Activity-Dependent Induction of Younger Biological Phenotypes

In several mammalian species, including humans, complex stimulation patterns such as cognitive and physical exercise lead to improvements in organ function, organism health and performance, as well as possibly longer lifespans. A framework is introduced here in which activity-dependent transcriptional programs, induced by these environmental stimuli, move somatic cells such as neurons and muscle cells toward a state that resembles younger cells to allow remodeling and adaptation of the organism. This cellular adaptation program targets several process classes that are heavily implicated in aging, such as mitochondrial metabolism, cell-cell communication, and epigenetic information processing, and leads to functional improvements in these areas. The activity-dependent gene program (ADGP) can be seen as a natural, endogenous cellular reprogramming mechanism that provides deep insight into the principles of inducible improvements in cell and organism function and can guide the development of therapeutic approaches for longevity. Here, these ADGPs are analyzed, exemplary critical molecular nexus points such as cAMP response element-binding protein, myocyte enhancer factor 2, serum response factor, and c-Fos are identified, and it is explored how one may leverage them to prevent, attenuate, and reverse human aging-related decline of body function.

Time course of plasticity-related alterations following the first exposure to amphetamine in juvenile rats

In vulnerable consumers, the first drug exposure induces various neurobehavioral adaptations that may represent the starting point toward addiction. Elucidating the neuroplastic mechanisms underlying that first rewarding experience would contribute to understanding the transition from recreational to compulsive drug use. In a preclinical model with juvenile rats, we analyzed the time-dependent fluctuations in the expression of neuroplasticity-related genes like the brain-derived neurotrophic factor (BDNF), its tropomyosin receptor kinase B (TrkB), the cAMP response element-binding protein (CREB), the microRNA-132, the Rho GTPase-activating protein 32 (p250GAP), the corticotropin-releasing factor (CRF), and the neurotransmitters contents in the nucleus accumbens (NAc) and the dorsal striatum (DS) 45, 90, and 180 min after an amphetamine (AMPH) injection. As expected, AMPH altered the concentration of norepinephrine, dopamine, DOPAC, and serotonin in a region- and time-dependent manner. Regarding gene expression, AMPH at 45 min upregulated BDNF and primiR-132 expression in NAc and downregulated TrkB expression in DS. At 90 min, AMPH upregulated TrkB, CREB, p250GAP, and primiR-132 expression in NAc and BDNF, primiR-132, and CRF in DS. At 180 min, only BNDF in NAc continued to be upregulated by AMPH. Based on the levels of AMPH-induced hyperactivity, we classified the rats as low and high AMPH responders. High AMPH responders characterized by overexpressing BDNF, CREB, p250GAP, and CRF in NAc and by showing lower levels of dopamine and serotonin metabolites and turnovers in both regions. Our findings demonstrated that a single AMPH administration is enough to induce neuroplastic adaptations, especially in the NAc of prone rats.

A Review of Molecular Interplay between Neurotrophins and miRNAs in Neuropsychological Disorders

Various neurotrophins (NTs), including nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4, promote cellular differentiation, survival, and maintenance, as well as synaptic plasticity, in the peripheral and central nervous system. The function of microRNAs (miRNAs) and other small non-coding RNAs, as regulators of gene expression, is pivotal for the appropriate control of cell growth and differentiation. There are positive and negative loops between NTs and miRNAs, which exert modulatory effects on different signaling pathways. The interplay between NTs and miRNAs plays a crucial role in the regulation of several physiological and pathological brain procedures. Emerging evidence suggests the diagnostic and therapeutic roles of the interactions between NTs and miRNAs in several neuropsychological disorders, including epilepsy, multiple sclerosis, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, schizophrenia, anxiety disorders, depression, post-traumatic stress disorder, bipolar disorder, and drug abuse. Here, we review current data regarding the regulatory interactions between NTs and miRNAs in neuropsychological disorders, for which novel diagnostic and/or therapeutic strategies are emerging. Targeting NTs-miRNAs interactions for diagnostic or therapeutic approaches needs to be validated by future clinical studies.

Silencing of miR-132-3p protects against neuronal injury following status epilepticus by inhibiting IL-1β-induced reactive astrocyte (A1) polarization

Mesial temporal lobe epilepsy (MTLE) is one of the most common refractory epilepsies and is usually accompanied by a range of brain pathological changes, such as neuronal injury and astrocytosis. Naïve astrocytes are readily converted to cytotoxic reactive astrocytes (A1) in response to inflammatory stimulation, suppressing the polarization of A1 protects against neuronal death in early central nervous system injury. Our previous study found that pro-inflammatory cytokines and miR-132-3p (hereinafter referred to as "miR-132") expression were upregulated, but how miR-132 affected reactive astrocyte polarization and neuronal damage during epilepsy is not fully understood. Here, we aimed to explore the effect and mechanism of miR-132 on A1 polarization. Our results confirmed that A1 markers were significantly elevated in the hippocampus of MTLE rats and IL-1β-treated primary astrocytes. In vivo, knockdown of miR-132 by lateral ventricular injection reduced A1 astrocytes, neuronal loss, mossy fiber sprouting, and remitted the severity of status epilepticus and the recurrence of spontaneous recurrent seizures. In vitro, the neuronal cell viability and axon length were reduced by additional treatment with A1 astrocyte conditioned media (ACM), and downregulation of astrocyte miR-132 rescued the inhibition of cell activity by A1 ACM, while the length of axons was further inhibited. The regulation of miR-132 on A1 astrocytes may be related to its target gene expression. Our results show that interfering with astrocyte polarization may be a breakthrough in the treatment of refractory epilepsy, which may extend to the research of other astrocyte polarization-mediated brain injuries.

Calcium and activity-dependent signaling in the developing cerebral cortex

Calcium influx can be stimulated by various intra- and extracellular signals to set coordinated gene expression programs into motion. As such, the precise regulation of intracellular calcium represents a nexus between environmental cues and intrinsic genetic programs. Mounting genetic evidence points to a role for the deregulation of intracellular calcium signaling in neuropsychiatric disorders of developmental origin. These findings have prompted renewed enthusiasm for understanding the roles of calcium during normal and dysfunctional prenatal development. In this Review, we describe the fundamental mechanisms through which calcium is spatiotemporally regulated and directs early neurodevelopmental events. We also discuss unanswered questions about intracellular calcium regulation during the emergence of neurodevelopmental disease, and provide evidence that disruption of cell-specific calcium homeostasis and/or redeployment of developmental calcium signaling mechanisms may contribute to adult neurological disorders. We propose that understanding the normal developmental events that build the nervous system will rely on gaining insights into cell type-specific calcium signaling mechanisms. Such an understanding will enable therapeutic strategies targeting calcium-dependent mechanisms to mitigate disease.

MicroRNAs and Synaptic Plasticity: From Their Molecular Roles to Response to Therapy

Synaptic plasticity is the ability of synapses to weaken or strengthen over time, in response to changes in the activity of the neurons. It is orchestrated by a variety of genes, proteins, and external and internal factors, especially epigenetic factors. MicroRNAs (miRNAs) are well-acknowledged epigenetic modulators that regulate the translation and degradation of target genes in the nervous system. Increasing evidence has suggested that a number of miRNAs play important roles in modulating various aspects of synaptic plasticity. The deregulation of miRNAs could be associated with pathological alterations in synaptic plasticity, which could lead to different CNS-related diseases. Herein, we provide an update on the role of miRNAs in governing synaptic plasticity. In addition, we also summarize recent researches on the role of miRNAs in drug addiction, and their targets and mechanism of action. Understanding of the way in which miRNAs contribute to synaptic plasticity provides rational clues in establishing the novel biomarkers and new therapeutic strategies for the diagnosis and treatment of plasticity-related diseases and drug addiction.

Dysregulated miRNAs in Progression and Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive degeneration of neurons due to the accumulation of amyloid-β peptide (Aβ) and hyper-phosphorylation of tau protein in the neuronal milieu leading to increased oxidative stress and apoptosis. Numerous factors contribute towards the progression of AD, including miRNA, which are 22-24 nucleotides long sequence which acts as critical regulators of cellular processes by binding to 3' UTR of mRNA, regulating its expression post-transcriptionally. This review aims to determine the miRNA with the most significant dysregulation in the brain and cerebrospinal fluid (CSF) of human patients. A systemized inclusion/exclusion criterion has been utilized based on selected keywords followed by screening of those articles to conclude a list of 8 highly dysregulated miRNAs based on the fold change of AD vs control patients, which could be used in clinical testing as these miRNAs play central role in the pathophysiology of AD. Furthermore, a network study of highly dysregulated miRNA estimated the association of these miRNA in the mediation of Aβ generation and aggregation, inhibition of autophagy, reduction of Aβ clearance, microglial and astrocytic activation, neuro-inflammation, tau hyper-phosphorylation, and synaptic loss.

miRNAs as potential diagnostic biomarkers and pharmacogenomic indicators in psychiatric disorders

The heterogeneity of psychiatric disorders and the lack of reliable biomarkers for prediction and treatments follow-up pose difficulties towards recognition and understanding of the molecular basis of psychiatric diseases. However, several studies based on NGS approaches have shown that miRNAs could regulate gene expression during onset and disease progression and could serve as potential diagnostic and pharmacogenomics biomarkers during treatment. We provide herein a detailed overview of circulating miRNAs and their expression profiles as biomarkers in schizophrenia, bipolar disorder and major depressive disorder and their role in response to specific treatments. Bioinformatics analysis of miR-34a, miR-106, miR-134 and miR-132, which are common among SZ, BD and MDD patients, showed brain enrichment and involvement in the modulation of critical signaling pathways, which are often deregulated in psychiatric disorders. We propose that specific miRNAs support accurate diagnosis and effective precision treatment of psychiatric disorders.

Dysregulated miRNAs as Biomarkers and Therapeutical Targets in Neurodegenerative Diseases

Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are representative neurodegenerative diseases (NDs) characterized by degeneration of selective neurons, as well as the lack of effective biomarkers and therapeutic treatments. In the last decade, microRNAs (miRNAs) have gained considerable interest in diagnostics and therapy of NDs, owing to their aberrant expression and their ability to target multiple molecules and pathways. Here, we provide an overview of dysregulated miRNAs in fluids (blood or cerebrospinal fluid) and nervous tissue of AD, PD, and ALS patients. By emphasizing those that are commonly dysregulated in these NDs, we highlight their potential role as biomarkers or therapeutical targets and describe the use of antisense oligonucleotides as miRNA therapies.

Role of miRNAs in Neurodegeneration: From Disease Cause to Tools of Biomarker Discovery and Therapeutics

Neurodegenerative diseases originate from neuronal loss in the central nervous system (CNS). These debilitating diseases progress with age and have become common due to an increase in longevity. The National Institute of Environmental Health Science’s 2021 annual report suggests around 6.2 million Americans are living with Alzheimer’s disease, and there is a possibility that there will be 1.2 million Parkinson’s disease patients in the USA by 2030. There is no clear-cut universal mechanism for identifying neurodegenerative diseases, and therefore, they pose a challenge for neurobiology scientists. Genetic and environmental factors modulate these diseases leading to familial or sporadic forms. Prior studies have shown that miRNA levels are altered during the course of the disease, thereby suggesting that these noncoding RNAs may be the contributing factor in neurodegeneration. In this review, we highlight the role of miRNAs in the pathogenesis of neurodegenerative diseases. Through this review, we aim to achieve four main objectives: First, we highlight how dysregulation of miRNA biogenesis led to these diseases. Second, we highlight the computational or bioinformatics tools required to identify the putative molecular targets of miRNAs, leading to biological molecular pathways or mechanisms involved in these diseases. Third, we focus on the dysregulation of miRNAs and their target genes leading to several neurodegenerative diseases. In the final section, we highlight the use of miRNAs as potential diagnostic biomarkers in the early asymptomatic preclinical diagnosis of these age-dependent debilitating diseases. Additionally, we discuss the challenges and advances in the development of miRNA therapeutics for brain targeting. We list some of the innovative strategies employed to deliver miRNA into target cells and the relevance of these viral and non-viral carrier systems in RNA therapy for neurodegenerative diseases. In summary, this review highlights the relevance of studying brain-enriched miRNAs, the mechanisms underlying their regulation of target gene expression, their dysregulation leading to progressive neurodegeneration, and their potential for biomarker marker and therapeutic intervention. This review thereby highlights ways for the effective diagnosis and prevention of these neurodegenerative disorders in the near future.

Regulation of acetylcholinesterase during the lipopolysaccharide-induced inflammatory responses in microglial cells

The non-classical function of acetylcholine (ACh) has been reported in neuroinflammation that represents the modulating factor in immune responses via activation of α7 nicotinic acetylcholine receptor (α7 nAChR), i.e., a cholinergic anti-inflammatory pathway (CAP). Acetylcholinesterase (AChE), an enzyme for ACh hydrolysis, has been proposed to have a non-classical function in immune cells. However, the involvement of AChE in neuroinflammation is unclear. Here, cultured BV2 cell, a microglial cell line, and primary microglia from rats were treated with lipopolysaccharide (LPS) to induce inflammation and to explore the regulation of AChE during this process. The expression profiles of AChE, α7 nAChR, and choline acetyltransferase (ChAT) were revealed in BV2 cells. The expression of AChE (G4 form) was induced significantly in LPS-treated BV2 cells: the induction was triggered by NF-κB and cAMP signaling. Moreover, ACh or α7 nAChR agonist suppressed the LPS-induced production of pro-inflammatory cytokines, as well as the phagocytosis of microglia, by activating α7 nAChR and followed by the regulation of NF-κB and CREB signaling. The ACh-induced suppression of inflammation was abolished in AChE overexpressed cells, but did not show a significant change in AChE mutant (enzymatic activity knockout) transfected cells. These results indicate that the neuroinflammation-regulated function of AChE may be mediated by controlling the ACh level in the brain system.

Deregulatory miRNA-BDNF Network Inferred from Dynamic Expression Changes in Schizophrenia

(1) Background: Brain-derived neurotrophic factor (BDNF) is one of the promising risk genes for schizophrenia (SZ), a disease with prominent dysregulation of miRNA networks. Here, we present a study of miRNA-BDNF co-expression changes in peripheral blood of SZ patients. (2) Methods: The expression levels of the BDNF mRNA and three validated binding miRNAs—miR-124-3p, miR-132-3p, and miR-206—were quantified in the blood of 48 healthy controls and 32 SZ patients before and after 12 weeks of treatment. The co-expression patterns were evaluated in the three groups. (3) Results: The expression levels of BDNF were significantly downregulated in SZ patients compared to the controls. After the treatment, the expression levels of BDNF were upregulated, while the expression levels of the three miRNAs were downregulated. Co-expression analyses showed positive correlations of this network in the SZ patients, while weak negative correlations were observed in the healthy controls. After the 12-week treatment, the overall correlation between BDNF and the three miRNAs reached the levels comparable to the healthy controls. (4) Conclusions: Our findings suggest the involvement of the miRNA-BDNF network in the onset and treatment of SZ.

Age-Dependent and Pathway-Specific Bimodal Action of Nicotine on Synaptic Plasticity in the Hippocampus of Mice Lacking the miR-132/212 Genes

Nicotine addiction develops predominantly during human adolescence through smoking. Self-administration experiments in rodents verify this biological preponderance to adolescence, suggesting evolutionary-conserved and age-defined mechanisms which influence the susceptibility to nicotine addiction. The hippocampus, a brain region linked to drug-related memory storage, undergoes major morpho-functional restructuring during adolescence and is strongly affected by nicotine stimulation. However, the signaling mechanisms shaping the effects of nicotine in young vs. adult brains remain unclear. MicroRNAs (miRNAs) emerged recently as modulators of brain neuroplasticity, learning and memory, and addiction. Nevertheless, the age-dependent interplay between miRNAs regulation and hippocampal nicotinergic signaling remains poorly explored. We here combined biophysical and pharmacological methods to examine the impact of miRNA-132/212 gene-deletion (miRNA-132/212-/-) and nicotine stimulation on synaptic functions in adolescent and mature adult mice at two hippocampal synaptic circuits: the medial perforant pathway (MPP) to dentate yrus (DG) synapses (MPP-DG) and CA3 Schaffer collaterals to CA1 synapses (CA3-CA1). Basal synaptic transmission and short-term (paired-pulse-induced) synaptic plasticity was unaltered in adolescent and adult miRNA-132/212-/- mice hippocampi, compared with wild-type controls. However, nicotine stimulation promoted CA3-CA1 synaptic potentiation in mature adult (not adolescent) wild-type and suppressed MPP-DG synaptic potentiation in miRNA-132/212-/- mice. Altered levels of CREB, Phospho-CREB, and acetylcholinesterase (AChE) expression were further detected in adult miRNA-132/212-/- mice hippocampi. These observations propose miRNAs as age-sensitive bimodal regulators of hippocampal nicotinergic signaling and, given the relevance of the hippocampus for drug-related memory storage, encourage further research on the influence of miRNAs 132 and 212 in nicotine addiction in the young and the adult brain.

Adult Neural Stem Cell Regulation by Small Non-coding RNAs: Physiological Significance and Pathological Implications

The adult neurogenic niches are complex multicellular systems, receiving regulatory input from a multitude of intracellular, juxtacrine, and paracrine signals and biological pathways. Within the niches, adult neural stem cells (aNSCs) generate astrocytic and neuronal progeny, with the latter predominating in physiological conditions. The new neurons generated from this neurogenic process are functionally linked to memory, cognition, and mood regulation, while much less is known about the functional contribution of aNSC-derived newborn astrocytes and adult-born oligodendrocytes. Accumulating evidence suggests that the deregulation of aNSCs and their progeny can impact, or can be impacted by, aging and several brain pathologies, including neurodevelopmental and mood disorders, neurodegenerative diseases, and also by insults, such as epileptic seizures, stroke, or traumatic brain injury. Hence, understanding the regulatory underpinnings of aNSC activation, differentiation, and fate commitment could help identify novel therapeutic avenues for a series of pathological conditions. Over the last two decades, small non-coding RNAs (sncRNAs) have emerged as key regulators of NSC fate determination in the adult neurogenic niches. In this review, we synthesize prior knowledge on how sncRNAs, such as microRNAs (miRNAs) and piwi-interacting RNAs (piRNAs), may impact NSC fate determination in the adult brain and we critically assess the functional significance of these events. We discuss the concepts that emerge from these examples and how they could be used to provide a framework for considering aNSC (de)regulation in the pathogenesis and treatment of neurological diseases.

The prominent role of miR-942 in carcinogenesis of tumors

As a family of short noncoding RNAs, MicroRNAs have been identified as possible biomarkers for cancer discovery and assist in therapy control due to their epigenetic involvement in gene expression and other cellular biological processes. In the present review, the evidence for reaching the clinical effect and the molecular mechanism of miR-942 in various kinds of cancer is amassed. Dysregulation of miR-942 amounts in different kinds of malignancies, as bladder cancer, esophageal squamous cell carcinoma, breast cancer, cervical cancer, gastric cancer, colorectal cancer, Kaposi's sarcoma, melanoma, Hepatocellular carcinoma, nonsmall-cell lung cancer, oral squamous cell carcinoma, osteosarcoma, ovarian cancer, pancreatic ductal adenocarcinoma, renal cell carcinoma, and prostate cancer has stated a considerable increase or decrease in its level indicating its function as oncogene or tumor suppressor. MiR-942 is included in cell proliferation, migration, and invasion through cell cycle pathways, including pathways of transforming growth factor-beta signaling pathways, Wnt pathway, JAK/STAT pathway, PI3K/AKT pathway, apoptosis pathway, hippo signaling pathway, lectin pathway, interferon-gamma signaling, signaling by G-protein coupled receptor, developmental genes, nuclear factor-kappa B pathway, Mesodermal commitment pathway, and T-cell receptor signaling in cancer. An important biomarker, MiR-942 is a potential candidate for prediction in several cancers. The present investigation introduced miR-942 as a prognostic marker for early discovery of tumor progression, metastasis, and development.

Three-Dimensional Genome Organization in Breast and Gynecological Cancers: How Chromatin Folding Influences Tumorigenic Transcriptional Programs

A growing body of research on the transcriptome and cancer genome has demonstrated that many gynecological tumor-specific gene mutations are located in cis-regulatory elements. Through chromosomal looping, cis-regulatory elements interact which each other to control gene expression by bringing distant regulatory elements, such as enhancers and insulators, into close proximity with promoters. It is well known that chromatin connections may be disrupted in cancer cells, promoting transcriptional dysregulation and the expression of abnormal tumor suppressor genes and oncogenes. In this review, we examine the roles of alterations in 3D chromatin interactions. This includes changes in CTCF protein function, cancer-risk single nucleotide polymorphisms, viral integration, and hormonal response as part of the mechanisms that lead to the acquisition of enhancers or super-enhancers. The translocation of existing enhancers, as well as enhancer loss or acquisition of insulator elements that interact with gene promoters, is also revised. Remarkably, similar processes that modify 3D chromatin contacts in gene promoters may also influence the expression of non-coding RNAs, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), which have emerged as key regulators of gene expression in a variety of cancers, including gynecological malignancies.

Small Molecule Drugs Targeting Non-Coding RNAs as Treatments for Alzheimer's Disease and Related Dementias

Despite the enormous burden of Alzheimer's disease and related dementias (ADRD) on patients, caregivers, and society, only a few treatments with limited efficacy are currently available. While drug development conventionally focuses on disease-associated proteins, RNA has recently been shown to be druggable for therapeutic purposes as well. Approximately 70% of the human genome is transcribed into non-protein-coding RNAs (ncRNAs) such as microRNAs, long ncRNAs, and circular RNAs, which can adopt diverse structures and cellular functions. Many ncRNAs are specifically enriched in the central nervous system, and their dysregulation is implicated in ADRD pathogenesis, making them attractive therapeutic targets. In this review, we first detail why targeting ncRNAs with small molecules is a promising therapeutic strategy for ADRD. We then outline the process from discovery to validation of small molecules targeting ncRNAs in preclinical studies, with special emphasis on primary high-throughput screens for identifying lead compounds. Screening strategies for specific ncRNAs will also be included as examples. Key challenges-including selecting appropriate ncRNA targets, lack of specificity of small molecules, and general low success rate of neurological drugs and how they may be overcome-will be discussed throughout the review.

MiRNA-132/212 regulates tight junction stabilization in blood-brain barrier after stroke

MicroRNA-132/212 has been supposed as a critical gene related to the blood–brain barrier (BBB) protection after stroke, but its regulation pathway including the upstream regulator and downstream targets is still unclear. Herein, we demonstrated the cAMP response element-binding protein (CREB)-regulated transcription coactivator-1 (CRTC1) to be the upstream regulator of miRNA-132/212 using CRTC1 knockout and wild-type mice. CRTC1 deletion led to the reduction of miRNA-132/212 expression in mice brain after ischemic stroke, significantly increased infarct volume, and aggravated BBB permeability with worsening neurological deficits. Furthermore, we identified that miRNA-132 repressed Claudin-1, tight junction-associated protein-1 (TJAP-1), and RNA-binding Fox-1 (RBFox-1) by directly binding to their respective 3′-untranslated regions, which alleviated the ischemic damage by enhancing neuronal survival and BBB integrity. Moreover, the co-culture of endothelial cells with CRTC1-deficient neurons aggravated the cell vulnerability to hypoxia, also supporting the idea that miRNA-132/212 cluster is regulated by CRTC1 and acts as a crucial role in the mitigation of ischemic damage. This work is a step forward for understanding the role of miRNA-132/212 in neurovascular interaction and may be helpful for potential gene therapy of ischemic stroke.

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.

The promise of microRNA-based therapies in Alzheimer's disease: challenges and perspectives

Multi-pathway approaches for the treatment of complex polygenic disorders are emerging as alternatives to classical monotarget therapies and microRNAs are of particular interest in that regard. MicroRNA research has come a long way from their initial discovery to the cumulative appreciation of their regulatory potential in healthy and diseased brain. However, systematic interrogation of putative therapeutic or toxic effects of microRNAs in (models of) Alzheimer's disease is currently missing and fundamental research findings are yet to be translated into clinical applications. Here, we review the literature to summarize the knowledge on microRNA regulation in Alzheimer's pathophysiology and to critically discuss whether and to what extent these increasing insights can be exploited for the development of microRNA-based therapeutics in the clinic.