Noncoding RNAs and Midbrain DA Neurons: Novel Molecular Mechanisms and Therapeutic Targets in Health and Disease

Circular RNAs regulate neuron size and migration of midbrain dopamine neurons during development

Midbrain dopamine (mDA) neurons play an essential role in cognitive and motor behaviours and are linked to different brain disorders. However, the molecular mechanisms underlying their development, and in particular the role of non-coding RNAs (ncRNAs), remain incompletely understood. Here, we establish the transcriptomic landscape and alternative splicing patterns of circular RNAs (circRNAs) at key developmental timepoints in mouse mDA neurons in vivo using fluorescence-activated cell sorting followed by short- and long-read RNA sequencing. In situ hybridisation shows expression of several circRNAs during early mDA neuron development and post-transcriptional silencing unveils roles for different circRNAs in regulating mDA neuron morphology. Finally, in utero electroporation and time-lapse imaging implicate circRmst, a circRNA with widespread morphological effects, in the migration of developing mDA neurons in vivo. Together, these data for the first time suggest a functional role for circRNAs in developing mDA neurons and characterise poorly defined aspects of mDA neuron development.

Epigenetic modifications in Parkinson's disease: A critical review

Parkinson's Disease (PD) is a progressive neurodegenerative disorder expected to increase by over 50% by 2030 due to increasing life expectancy. The disease's hallmarks include slow movement, tremors, and postural instability. Impaired protein processing is a major factor in the pathophysiology of PD, leading to the buildup of aberrant protein aggregates, particularly misfolded α-synuclein, also known as Lewy bodies. These Lewy bodies lead to inflammation and further death of dopaminergic neurons, leading to imbalances in excitatory and inhibitory neurotransmitters, causing excessive uncontrollable movements called dyskinesias. It was previously suggested that a complex interplay involving hereditary and environmental variables causes the specific death of neurons in PD; however, the exact mechanism of the association involving the two primary modifiers is yet unknown. An increasing amount of research points to the involvement of epigenetics in the onset and course of several neurological conditions, such as PD. DNA methylation, post-modifications of histones, and non-coding RNAs are the primary examples of epigenetic alterations, that is defined as alterations to the expression of genes and functioning without modifications in DNA sequence. Epigenetic modifications play a significant role in the development of PD, with genes such as Parkin, PTEN-induced kinase 1 (PINK1), DJ1, Leucine-Rich Repeat Kinase 2 (LRRK2), and alpha-synuclein associated with the disease. The aberrant epigenetic changes implicated in the pathophysiology of PD and their impact on the design of novel therapeutic approaches are the primary focus of this review.

Hsa_circ_0054220 Upregulates HMGA1 by the Competitive RNA Pattern to Promote Neural Impairment in MPTP Model of Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disease. Circular RNAs (circRNAs) have been confirmed to regulate neurodegenerative diseases. This study was aimed to explore hsa_circ_0054220 functions in PD. MPP-stimulated SH-SY5Y cells were established as the PD cell model. PD mouse model was established by MPTP. Gene expression in cells and tissues was tested by RT-qPCR. Cell viability and apoptosis were evaluated through CCK-8 and TUNEL assays. The interactions of RNAs were determined by RNA pull-down assay, RIP assay, and luciferase reporter assay. Circ_0054220 expressed at a high level in MPP-treated SH-SY5Y cells. Circ_0054220 inhibition promoted viability and suppressed apoptosis in MPP-stimulated cells. Furthermore, we found that circ_0054220 can competitively bind to miR-145 and miR-625 to upregulate high mobility group A1 (HMGA1) expression. HMGA1 was positively regulated by circ_0054220 and overexpressed in MPP-treated cells as well as the striatum (STR), substantia nigra pars compacta (SNpc), and serum of MPTP-induced mouse model of PD. HMGA1 overexpression counteracted the function of circ_0054220 silencing on cell apoptosis. Furthermore, HMGA1 inhibition notably alleviated motor dysfunction and increased the quantity of neurons in mice resembling PD. Circ_0054220 upregulates HMGA1 by the competitive endogenous RNAs (ceRNA) pattern to promote neural impairment in PD.

Effects of mind-body therapies on schizophrenia: A systematic review and network meta-analysis

OBJECTIVE

The objective of this meta-analysis is to evaluate and compare the effectiveness of different mind-body therapies in reducing the symptoms of schizophrenia.

METHODS

A systematic search was performed using databases such as PubMed, Embase, Cochrane Library, Web of Science, and Scopus. Randomized controlled trials that assessed the effects of mind-body therapies on patients with schizophrenia were included. The search covered the period between the inception of each database and November 17th, 2022. The methodological quality of the trials was assessed using the Cochrane risk of bias tool. A network meta-analysis was conducted to compare the effects of various mind-body therapies, including Yoga, Mindfulness, Tai Chi, Baduanjin, and Yijinjing.

RESULTS

The analysis included 22 randomized controlled trials involving a total of 2064 subjects. The network meta-analysis revealed that Yoga and Mindfulness interventions were more effective than other mind-body therapies in reducing the symptoms of schizophrenia. Specifically, Yoga improved PANSS-positive symptom scores (SUCRA: 74.8 %) and PANSS-negative symptom scores (SUCRA: 80.4 %), whereas Mindfulness improved PANSS-positive symptom scores (SUCRA: 85.6 %).

CONCLUSION

The findings of this study indicate that Yoga may be a promising intervention for the treatment of schizophrenia. However, the small sample size and the low quality of the included studies have limited the generalizability of our findings Therefore, this study must be understood with caution, and further investigation is warranted when more relevant studies emerge.

MicroRNA schizophrenia: Etiology, biomarkers and therapeutic targets

The three sets of symptoms associated with schizophrenia-positive, negative, and cognitive-are burdensome and have serious effects on public health, which affects up to 1% of the population. It is now commonly believed that in addition to the traditional dopaminergic mesolimbic pathway, the etiology of schizophrenia also includes neuronal networks, such as glutamate, GABA, serotonin, BDNF, oxidative stress, inflammation and the immune system. Small noncoding RNA molecules called microRNAs (miRNAs) have come to light as possible participants in the pathophysiology of schizophrenia in recent years by having an impact on these systems. These small RNAs regulate the stability and translation of hundreds of target transcripts, which has an impact on the entire gene network. There may be improved approaches to treat and diagnose schizophrenia if it is understood how these changes in miRNAs alter the critical related signaling pathways that drive the development and progression of the illness.

Direct Cell Conversion of Somatic Cells into Dopamine Neurons: Achievements and Perspectives

In the last decade, direct reprogramming has emerged as a novel strategy to obtain mature and functional dopamine neurons from somatic cells. This approach could overcome issues linked to the use of human pluripotent stem cells such as ethical concerns and safety problems that can arise from the overgrowth of undifferentiated cells after transplantation. Several conversion methodologies have been developed to obtain induced DA neurons (iDANs) or induced DA neuron progenitors (iDPs). iDANs have also proved to successfully integrate in mice striatum, alleviating Parkinson's disease (PD) motor symptoms. In the next decade, human iDANs and/or iDPs could be translated to clinic to achieve a patient-tailored therapy, but current critical issues hinder this goal, such as the low conversion rate of adult human fibroblasts and the risks associated with lentiviral delivery of conversion factors. In this study, we summarize the strategies and recent improvements developed for the generation of mouse and human iDANs/iDPs. Furthermore, we discuss the more recent application of in vivo direct conversion, which may enable clinical therapies for PD by means of brain in situ delivery of dopaminergic reprogramming transcription factors.

SNHG14 Upregulation Was a Molecular Mechanism Underlying MPP+ Neurotoxicity in Dopaminergic SK-N-SH Cells via SNHG14-miR-519a-3p-ATG10 ceRNA Pathway

Long non-coding RNA small nuclear RNA host gene 14 (SNHG14) is a novel contributor of dopaminergic neuronal injury in Parkinson's disease. We further explored its role in 1-methyl-4-phenylpyridinium (MPP⁺)-damaged dopaminergic neurons (DAn) and the possible mechanism involving SNHG14, microRNA (miR)-519a-3p, and autophagy-related 10 (ATG10). MPP⁺ cytotoxicity was measured by MTS cell viability assay, flow cytometry, and a series of assay kits for detecting apoptosis and oxidative stress. Molecule expression was examined by qPCR and Western blotting, and RNA interaction was predicted by starBase2.0 of ENCORI platform and confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. SNHG14 and ATG10 expression was increased, and miR-519a-3p was decreased in MPP⁺-treated SK-N-SH cells, and SNHG14 knockdown alleviated MPP⁺-induced SK-N-SH cell damage by regulating cell viability, cell cycle arrest, apoptosis, and oxidative stress. Additionally, antisense RNA of miR-519a-3p abated the suppressive role of SNHG14 knockdown, and ectopic expression of ATG10 counteracted the protective role of miR-519a-3p against MPP⁺ neurotoxicity. Mechanistically, SNHG14 and ATG10 were competitive endogenous RNAs (ceRNAs) for miR-519a-3p, and ATG10 expression could be positively modulated by SNHG14 via sponging miR-519a-3p. Target silencing SNHG14 and restoring miR-519a-3p could prevent DAn from MPP⁺ toxicity via regulation of ATG10.

MicroRNA Roles in Cell Reprogramming Mechanisms

Cell reprogramming is a groundbreaking technology that, in few decades, generated a new paradigm in biomedical science. To date we can use cell reprogramming to potentially generate every cell type by converting somatic cells and suitably modulating the expression of key transcription factors. This approach can be used to convert skin fibroblasts into pluripotent stem cells as well as into a variety of differentiated and medically relevant cell types, including cardiomyocytes and neural cells. The molecular mechanisms underlying such striking cell phenotypes are still largely unknown, but in the last decade it has been proven that cell reprogramming approaches are significantly influenced by non-coding RNAs. Specifically, this review will focus on the role of microRNAs in the reprogramming processes that lead to the generation of pluripotent stem cells, neurons, and cardiomyocytes. As highlighted here, non-coding RNA-forced expression can be sufficient to support some cell reprogramming processes, and, therefore, we will also discuss how these molecular determinants could be used in the future for biomedical purposes.

Epigenetics of Aggression

Aggression is a complex behavioral trait modulated by both genetic and environmental influences on gene expression. By controlling gene expression in a reversible yet potentially lasting manner in response to environmental stimulation, epigenetic mechanisms represent prime candidates in explaining both individual differences in aggression and the development of elevated aggressive behaviors following life adversity. In this manuscript, we review the evidence for an epigenetic basis in the development and expression of aggression in both humans and related preclinical animal models. In particular, we discuss reports linking DNA methylation, histone post-translational modifications, as well as non-coding RNA, to the regulation of a variety of genes implicated in the neurobiology of aggression including neuropeptides, the serotoninergic and dopaminergic systems, and stress response related systems. While clinical reports do reveal interesting patterns of DNA methylation underlying individual differences and experience-induced aggressive behaviors, they do, in general, face the challenge of linking peripheral observations to central nervous system regulations. Preclinical studies, on the other hand, provide detailed mechanistic insights into the epigenetic reprogramming of gene expression following life adversities. Although the functional link to aggression remains unclear in most, these studies together do highlight the involvement of epigenetic events driven by DNA methylation, histone modifications, and non-coding RNA in the neuroadaptations underlying the development and expression of aggression.

MicroRNAs and Stem-like Properties: The Complex Regulation Underlying Stemness Maintenance and Cancer Development

Embryonic stem cells (ESCs) have the extraordinary properties to indefinitely proliferate and self-renew in culture to produce different cell progeny through differentiation. This latter process recapitulates embryonic development and requires rounds of the epithelial-mesenchymal transition (EMT). EMT is characterized by the loss of the epithelial features and the acquisition of the typical phenotype of the mesenchymal cells. In pathological conditions, EMT can confer stemness or stem-like phenotypes, playing a role in the tumorigenic process. Cancer stem cells (CSCs) represent a subpopulation, found in the tumor tissues, with stem-like properties such as uncontrolled proliferation, self-renewal, and ability to differentiate into different cell types. ESCs and CSCs share numerous features (pluripotency, self-renewal, expression of stemness genes, and acquisition of epithelial-mesenchymal features), and most of them are under the control of microRNAs (miRNAs). These small molecules have relevant roles during both embryogenesis and cancer development. The aim of this review was to recapitulate molecular mechanisms shared by ESCs and CSCs, with a special focus on the recently identified classes of microRNAs (noncanonical miRNAs, mirtrons, isomiRs, and competitive endogenous miRNAs) and their complex functions during embryogenesis and cancer development.

Chemical and Biological Molecules Involved in Differentiation, Maturation, and Survival of Dopaminergic Neurons in Health and Parkinson's Disease: Physiological Aspects and Clinical Implications

Parkinson’s disease (PD) is one of the most common neurodegenerative disease characterized by a specific and progressive loss of dopaminergic (DA) neurons and dopamine, causing motor dysfunctions and impaired movements. Unfortunately, available therapies can partially treat the motor symptoms, but they have no effect on non-motor features. In addition, the therapeutic effect reduces gradually, and the prolonged use of drugs leads to a significative increase in the number of adverse events. For these reasons, an alternative approach that allows the replacement or the improved survival of DA neurons is very appealing for the treatment of PD patients and recently the first human clinical trials for DA neurons replacement have been set up. Here, we review the role of chemical and biological molecules that are involved in the development, survival and differentiation of DA neurons. In particular, we review the chemical small molecules used to differentiate different type of stem cells into DA neurons with high efficiency; the role of microRNAs and long non-coding RNAs both in DA neurons development/survival as far as in the pathogenesis of PD; and, finally, we dissect the potential role of exosomes carrying biological molecules as treatment of PD.

lncRNA MIR155HG Alleviates Depression-Like Behaviors in Mice by Regulating the miR-155/BDNF Axis

Depression is one of most common psychiatric disorders, and the detailed molecular mechanism remains to be fully elucidated. Brain-derived neurotrophic factor (BDNF) is a critical neurotrophic factor that is decreased and closely involved in the development of depression. Noncoding RNAs are central regulators of cellular activities that modulate target genes. However, the roles of long noncoding RNA (lncRNA) MIR155HG and miRNA-155 (miR-155) in the pathophysiology of depression are unclear. In the present study, we aimed to explore the effects of lncRNA MIR155HG and miR-155 on the development of depression and uncover the underlying molecular mechanism. Real-time quantitative polymerase chain reaction was used to examine the expression of MIR155HG and miR-155. Western blotting was applied to measure the expression of BDNF. A luciferase reporter assay was utilized to determine the regulatory relationship between MIR155HG and miR-155. Our current work found that lncRNA MIR155HG and BDNF levels decreased while miR-155 levels increased in the hippocampal region of CUMS (chronic unpredictable mild stress) mice, a well-accepted mouse model of depression. Moreover, MIR155HG rescued while miR-155 exacerbated the depression-like behaviors of CUMS mice. Through bioinformatics analysis and luciferase reporter assays, we found that MIR155HG directly bound to and negatively modulated the expression of miR-155. Moreover, increased miR-155 was found to repress the expression of BDNF, a critical neurotrophic factor that has been reported to alleviate the depression-like behaviors of CUMS mice. Our present study revealed that lncRNA MIR155HG protected CUMS mice by regulating the miR-155/BDNF axis. Our study aimed to understand the pathophysiology of depression and provided potential therapeutic targets to diagnose and treat depression.