Integrated analysis of circRNA-associated ceRNA network in ischemic stroke

Introduction: Stroke, of which ischemic stroke (IS) is the major type, is the second leading cause of disability and death worldwide. Circular RNAs (circRNAs) are reported to play important role in the physiology and pathology of IS. CircRNAs often act as competing endogenous RNA (ceRNA) to regulate gene expression by acting as miRNA sponges. However, whole transcriptome-wide screenings of circRNA-mediated ceRNA networks associated with IS are still lacking. In the present study, we constructed a circRNA-miRNA-mRNA ceRNA network by whole transcriptome-wide analysis. Methods: CircRNAs, miRNAs and mRNAs expression profiles were downloaded from the Gene Expression Omnibus (GEO) datasets. We identified differentially expressed (DE) circRNAs, miRNAs, and mRNAs in IS patients. StarBase and CircBank databases were used to predict the miRNA targets of DEcircRNAs, and mirDIP database was used to predict the mRNA targets of DEmiRNAs. CircRNA-miRNA pairs and miRNA-mRNA pairs were established. Then, we identified hub genes via protein-protein interaction analysis and constructed a core ceRNA sub-network. Results: In total, 276 DEcircRNAs, 43 DEmiRNAs, and 1926 DEmRNAs were explored. The ceRNA network included 69 circRNAs, 24 miRNAs, and 92 mRNAs. The core ceRNA subnetwork included hsa_circ_0011474, hsa_circ_0023110, CDKN1A, FHL2, RPS2, CDK19, KAT6A, CBX1, BRD4, and ZFHX3. Discussion: In conclusion, we established a novel hsa_circ_0011474 - hsa-miR-20a-5p/hsa-miR-17-5p - CDKN1A ceRNA regulatory axis associated with IS. Our findings provide new insights into the pathogenesis of IS and offer promising diagnostic and predictive biomarkers.

Research progress in role of exosomes exosomes in mental disorders

Exosomes are a class of extracellular vesicles with a structure of lipid bilayer-membrane. In the central nervous system (CNS), exosomes can be secreted from both neurons and glial cells. Exosomes released into the extracellular matrix can freely cross the blood-brain barrier and function as crucial carriers of cellular communication and substance exchange in the CNS. Exosomes play a key role in the pathological process of mental disorders such as schizophrenia, depression, and bipolar disorder, and they have the potential to be used as a targeted carrier of antipsychotic medications. Exosomes are likely to become a new tool in the future to aid in the early prevention, accurate diagnosis, and effective treatment for people with mental disorders.

The genetic architecture of fornix white matter microstructure and their involvement in neuropsychiatric disorders

The fornix is a white matter bundle located in the center of the hippocampaldiencephalic limbic circuit that controls memory and executive functions, yet its genetic architectures and involvement in brain disorders remain largely unknown. We carried out a genome-wide association analysis of 30,832 UK Biobank individuals of the six fornix diffusion magnetic resonance imaging (dMRI) traits. The post-GWAS analysis allowed us to identify causal genetic variants in phenotypes at the single nucleotide polymorphisms (SNP), locus, and gene levels, as well as genetic overlap with brain health-related traits. We further generalized our GWAS in adolescent brain cognitive development (ABCD) cohort. The GWAS identified 63 independent significant variants within 20 genomic loci associated (P < 8.33 × 10^-9) with the six fornix dMRI traits. Geminin coiled-coil domain containing (GMNC) and NUAK family SNF1-like kinase 1 (NUAK1) gene were highlighted, which were found in UKB and replicated in ABCD. The heritability of the six traits ranged from 10% to 27%. Gene mapping strategies identified 213 genes, where 11 were supported by all of four methods. Gene-based analyses revealed pathways relating to cell development and differentiation, with astrocytes found to be significantly enriched. Pleiotropy analyses with eight neurological and psychiatric disorders revealed shared variants, especially with schizophrenia under the conjFDR threshold of 0.05. These findings advance our understanding of the complex genetic architectures of fornix and their relevance in neurological and psychiatric disorders.

Fecal microbiota transplantation confirmed that 919 Syrup reduced the ratio of erucamide to 5-AVAB in hippocampus to alleviate postpartum depression by regulating gut microbes

Background

Postpartum depression has a crucial impact on the physical and psychological comfort and the work of postnatal women, the growth and development of infants and mental health in adulthood. Finding a safe and effective anti-postnatal depression drug is currently an important research goal in this field.

Methods

In this study, the forced swimming test (FST) and tail suspension test (TST) were used to evaluated the depressive behaviors of mice, and the changes of metabolites and intestinal microflora in mice with postpartum depression were examined through non-target metabolomics and 16S RNA sequencing respectively.

Results

We found that traditional Chinese medicine compound 919 Syrup could alleviate postpartum depression in mice and inhibit the elevated erucamide level in depressive hippocampus. However, mice treated with antibiotics were not sensitive to the anti-postnatal depression effect of 919 Syrup, and the level of 5-aminovaleric acid betaine (5-AVAB) in their hippocampus was significantly decreased. Transplanting fecal microflora treated with 919 Syrup could effectively improve the depressive behaviors of mice, upregulate the level of gut-derived 5-AVAB in the hippocampus, and downregulate the level of erucamide. Erucamide was significantly negatively correlated with increased Bacteroides in intestine after 919 Syrup treatment or fecal transplantation, and significantly positively correlated with Ruminococcaceae UCG-014 which was increased in feces of mice with postpartum depression. The increase of Bacteroides, Lactobacillus, and Ruminiclostridium in intestine after fecal transplantation had a clearly positive correlation with 5-AVAB.

Conclusion

In brief, 919 Syrup may downregulate the ratio of hippocampal metabolites erucamide to 5-AVAB by regulating intestinal flora to alleviate postpartum depression, laying a scientific foundation for future pathological research and development of therapeutic drugs for postpartum depression.

Gut microbiota decreased inflammation induced by chronic unpredictable mild stress through affecting NLRP3 inflammasome

Dysbiosis of the gut microbiota is associated with the development of depression, but the underlying mechanism remains unclear. The aim of this study was to determine the relationship between microbiota and NLRP3 inflammasome induced by chronic unpredictable mild stress (CUMS). Fecal transplantation (FMT) experiment was conducted to elucidate the potential mechanism. Levels of NLRP3 inflammasome, microbiota, inflammatory factors and tight junction proteins were measured. CUMS stimulation significantly increased the levels of NLRP3, Caspase-1 and ASC in brain and colon(p<0.05), decreased the levels of tight junction proteins Occludin and ZO-1 (p<0.05). Interestingly, increased NLRP3 inflammasome and inflammatory cytokines and decreased tight junction proteins were found in antibiotic-treated (Abx) rats received CUMS rat fecal microbiota transplantation. Furthermore, fecal microbiota transplantation altered the microbiota in Abx rats, which partially overlapped with that of the donor rats. Importantly, probiotic administration amended the alteration of microbiota induced by CUMS treatment, then reduced the levels of NLRP3 inflammasome and inflammatory factors. In conclusion, these findings suggested that depression-like behaviors induced by CUMS stimulation were related to altered gut microbiota, broke the intestinal barrier, promoted the expression of NLRP3 inflammasome and elevated inflammation. Therefore, improving the composition of microbiota via probiotic can attenuate inflammation by amending the microbiota and suppressing the activation of NLRP3 inflammasome, which is considered as a novel therapeutic strategy for depression.

Akkermansia muciniphila-Nlrp3 is involved in the neuroprotection of phosphoglycerate mutase 5 deficiency in traumatic brain injury mice

INTRODUCTION

Gut-microbiota-brain axis is a potential treatment to decrease the risk of chronic traumatic encephalopathy following traumatic brain injury (TBI). Phosphoglycerate mutase 5 (PGAM5), a mitochondrial serine/threonine protein phosphatase, resides in mitochondrial membrane and regulates mitochondrial homeostasis and metabolism. Mitochondria mediates intestinal barrier and gut microbiome.

OBJECTIVES

This study investigated the association between PGAM5 and gut microbiota in mice with TBI.

METHODS

The controlled cortical impact injury was established in mice with genetically-ablated Pgam5 (Pgam5-/-) or wild type, and WT male mice were treated with fecal microbiota transplantation (FMT) from male Pgam5-/- mice or Akkermansia muciniphila (A. muciniphila). Then the gut microbiota abundance, blood metabolites, neurological function, and nerve injury were detected.

RESULTS

Treated with antibiotics for suppressing gut microbiota in Pgam5-/- mice partially relieved the role of Pgam5 deficiency in the improvement of initial inflammatory factors and motor dysfunction post-TBI. Pgam5 knockout exhibited an increased abundance of A. muciniphila in mice. FMT from male Pgam5-/- mice enabled better maintenance of amino acid metabolism and peripherial environment than that in TBI-vehicle mice, which suppressed neuroinflammation and improved neurological deficits, and A. muciniphila was negatively associated with intestinal mucosal injury and neuroinflammation post-TBI. Moreover, A. muciniphila treatment ameliorated neuroinflammation and nerve injury by regulating Nlrp3 inflammasome activation in cerebral cortex with TBI.

CONCLUSION

Thus, the present study provides evidence that Pgam5 is involved in gut microbiota-mediated neuroinflammation and nerve injury, with A. muciniphila-Nlrp3 contributing to peripheral effects.

Gut microbiota mediated the effects of high relative humidity on lupus in female MRL/lpr mice

INTRODUCTION

The relationship between humidity and systemic lupus erythematosus (SLE) has yielded inconsistent results in prior research, while the effects of humidity on lupus in animal experiments and its underlying mechanism remain inadequately explored.

METHODS

The present study aimed to investigate the impact of high humidity (80 ± 5%) on lupus using female and male MRL/lpr mice, with a particular focus on elucidating the role of gut microbiota in this process. To this end, fecal microbiota transplantation (FMT) was employed to transfer the gut microbiota of MRL/lpr mice under high humidity to blank MRL/lpr mice under normal humidity (50 ± 5%), allowing for an assessment of the effect of FMT on lupus.

RESULTS

The study revealed that high humidity exacerbated lupus indices (serum anti-dsDNA, ANA, IL-6, and IFN- g, and renal pathology) in female MRL/lpr mice but had no significant effect on male MRL/lpr mice. The aggravation of lupus caused by high humidity may be attributed to the increased abundances of the Rikenella, Romboutsia, Turicibacter, and Escherichia-Shigella genera in female MRL/lpr mice. Furthermore, FMT also exacerbated lupus in female MRL/lpr mice but not in male MRL/lpr mice.

CONCLUSION

In summary, this study has demonstrated that high humidity exacerbated lupus by modulating gut microbiota in female MRL/lpr mice. The findings underscore the importance of considering environmental factors and gut microbiota in the development and progression of lupus, particularly among female patients.

Roles of Aging, Circular RNAs, and RNA Editing in the Pathogenesis of Amyotrophic Lateral Sclerosis: Potential Biomarkers and Therapeutic Targets

Amyotrophic lateral sclerosis (ALS) is an incurable motor neuron disease caused by upper and lower motor neuron death. Despite advances in our understanding of ALS pathogenesis, effective treatment for this fatal disease remains elusive. As aging is a major risk factor for ALS, age-related molecular changes may provide clues for the development of new therapeutic strategies. Dysregulation of age-dependent RNA metabolism plays a pivotal role in the pathogenesis of ALS. In addition, failure of RNA editing at the glutamine/arginine (Q/R) site of GluA2 mRNA causes excitotoxicity due to excessive Ca²⁺ influx through Ca²⁺-permeable α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors, which is recognized as an underlying mechanism of motor neuron death in ALS. Circular RNAs (circRNAs), a circular form of cognate RNA generated by back-splicing, are abundant in the brain and accumulate with age. Hence, they are assumed to play a role in neurodegeneration. Emerging evidence has demonstrated that age-related dysregulation of RNA editing and changes in circRNA expression are involved in ALS pathogenesis. Herein, we review the potential associations between age-dependent changes in circRNAs and RNA editing, and discuss the possibility of developing new therapies and biomarkers for ALS based on age-related changes in circRNAs and dysregulation of RNA editing.

Effect of Rosiglitazone, the Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, on Apoptosis, Inflammatory Cytokines and Oxidative Stress in pentylenetetrazole-Induced Seizures in Kindled Mice

A growing body of evidence has shown that seizure can trigger inflammatory cascades through increasing the expression of several inflammatory cytokines. It has been proved that peroxisome proliferator-activated receptor-γ agonists have immunomodulatory, anti-inflammatory, and neuroprotective effects beyond the putative hypoglycemic effects. Thus, we investigated the inhibitory effect of rosiglitazone on the development of pentylenetetrazol (PTZ)-induced kindling via affecting the inflammatory pathway. Male C57BL/6 mice were randomly divided into vehicle group (0.1% DMSO), PTZ-group and rosiglitazone-PTZ-group. Kindling was induced by the administration of PTZ (40 mg/kg, i.p) every other day and mice were observed for 20 min after each PTZ injection. Twenty-four hours after the last dose, animals were euthanized and hippocampus was isolated. The level of Malondialdehyde (MDA), Superoxide Dismutase (SOD), and Catalase (CAT) activity were quantified in hippocampus by biochemical methods. The protein levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, caspase-3, iNOS, PPAR-γ, Bcl-2, or Bax factors were measured with western blotting. Also, the quantitative real-time PCR were used to evaluate the mRNA expression of those factors. Pretreatment with rosiglitazone significantly prevented the progression of kindling in comparison with control group. The rosiglitazone significantly decreased the MDA level and increased the CAT, and SOD levels in the rosiglitazone treated mice compared to those in the PTZ group (P < 0.01). Using real-time PCR and Western blotting assay, similar results were obtained. The expression levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, Bax or PPAR-γ were significantly changed in the brain. The results of this study suggest that effect of rosiglitazone may be crucial in its ability to protect against the neuronal damage caused by PTZ induced seizure.

The Brain-Gut-Microbiota Interplay in Depression: a key to design innovative therapeutic approaches

Depression is the most prevalent mental disorder in the world associated with huge socio-economic consequences. While depressive-related symptoms are well known, the molecular mechanisms underlying disease pathophysiology and progression remain largely unknown. The gut microbiota (GM) is emerging as a key regulator of the central nervous system homeostasis by exerting fundamental immune and metabolic functions. In turn, the brain influences the intestinal microbial composition through neuroendocrine signals, within the so-called gut microbiota-brain axis. The balance of this bidirectional crosstalk is important to ensure neurogenesis, preserve the integrity of the blood-brain barrier and avoid neuroinflammation. Conversely, dysbiosis and gut permeability negatively affect brain development, behavior, and cognition. Furthermore, although not fully defined yet, changes in the GM composition in depressed patients are reported to influence the pharmacokinetics of common antidepressants by affecting their absorption, metabolism, and activity. Similarly, neuropsychiatric drugs may shape in turn the GM with an impact on the efficacy and toxicity of the pharmacological intervention itself. Consequently, strategies aimed at re-establishing the correct homeostatic gut balance (i.e., prebiotics, probiotics, fecal microbiota transplantation, and dietary interventions) represent an innovative approach to improve the pharmacotherapy of depression. Among these, probiotics and the Mediterranean diet, alone or in combination with the standard of care, hold promise for clinical application. Therefore, the disclosure of the intricate network between GM and depression will give precious insights for innovative diagnostic and therapeutic approaches towards depression, with profound implications for drug development and clinical practice.

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.

Clinical Application of Circular RNAs as Biomarkers in Acute Ischemic Stroke

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

Insights into N6-methyladenosine (m6A) modification of noncoding RNA in tumor microenvironment

N6-methyladenosine (m6A) is the most abundant RNA modification in eukaryotes, and it participates in the regulation of pathophysiological processes in various diseases, including malignant tumors, by regulating the expression and function of both coding and non-coding RNAs (ncRNAs). More and more studies demonstrated that m6A modification regulates the production, stability, and degradation of ncRNAs and that ncRNAs also regulate the expression of m6A-related proteins. Tumor microenvironment (TME) refers to the internal and external environment of tumor cells, which is composed of numerous tumor stromal cells, immune cells, immune factors, and inflammatory factors that are closely related to tumors occurrence and development. Recent studies have suggested that crosstalk between m6A modifications and ncRNAs plays an important role in the biological regulation of TME. In this review, we summarized and analyzed the effects of m6A modification-associated ncRNAs on TME from various perspectives, including tumor proliferation, angiogenesis, invasion and metastasis, and immune escape. Herein, we showed that m6A-related ncRNAs can not only be expected to become detection markers of tumor tissue samples, but can also be wrapped into exosomes and secreted into body fluids, thus exhibiting potential as markers for liquid biopsy. This review provides a deeper understanding of the relationship between m6A-related ncRNAs and TME, which is of great significance to the development of a new strategy for precise tumor therapy.

The potential health risks of short-chain chlorinated paraffin: A mini-review from a toxicological perspective

Short-chain chlorinated paraffins (SCCPs) are ubiquitously distributed in various environmental matrics due to their wide production and consumption globally in the past and ongoing production and use in some developing countries. SCCPs have been detected in various human samples including serum, milk, placenta, nail, and hair, and internal SCCP levels were found to be positively correlated with biomarkers of some diseases. While the environmental occurrence has been reported in a lot of studies, the toxicity and underlying molecular mechanisms of SCCPs remain largely unknown. The current tolerable daily intakes (TDIs) recommended by the world health organization/international programme on chemical safety (WHO/IPCS, 100 μg/kg bw/d) and the UK Committee on Toxicity (COT, 30 μg/kg bw/d) were obtained based on a no observed adverse effect level (NOAEL) of SCCP from the repeated-dose study (90 d exposure) in rodents performed nearly 40 years ago. Importantly, the health risks assessment of SCCPs in a variety of studies has shown that the estimated daily intakes (EDIs) may approach and even over the established TDI by UK COT. Furthermore, recent studies revealed that lower doses of SCCPs could also result in damage to multiple organs including the liver, kidney, and thyroid. Long-term effects of SCCPs at environmental-related doses are warranted.

Identification and characterization of circular RNA in the model of autism spectrum disorder from PM2.5 exposure

PM_2.5 induces a series of effects on neurological disorders, including autism spectrum disorder (ASD), however, the mechanism is not completely clear yet. Circular RNAs (circRNAs) are a class of closed-loop structures that can be stably expressed in vivo. In our experiments, rats exposed to PM_2.5 exhibited autism-like phenotypes, such as anxiety, and memory loss. To explore the etiology, we performed transcriptome sequencing and found significant differences in the expression of circRNA. A total of 7770 circRNAs were identified between the control and experimental groups, 18 of which were differentially expressed, we selected ten circRNAs and performed qRT-PCR and Sanger sequencing to validate them. By GO and KEGG enrichment analysis, we found differentially expressed circRNAs that were mainly enriched in processes related to placental development and reproduction. Finally, using bioinformatics, we predicted miRNAs and mRNAs that circ-Mbd5 and circ-Ash1l might regulate and constructed circRNA-miRNA-mRNA networks involving genes associated with ASD, suggesting that circRNAs might regulate the occurrence of ASD.

Detailed profiling of m6A modified circRNAs and synergistic effects of circRNA and environmental risk factors for coronary artery disease

The modification of N6-methyladenosine (m6A) modification is implicated in human diseases. However, considerable uncertainty is associated with the regulatory mechanisms of m6A circRNAs in coronary artery disease (CAD), which require further clarification. In this study, m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq) was conducted to investigate m6A-modified circRNAs in human coronary artery smooth muscle cells (HCASMCs) and to identify potential biomarkers for CAD. A total of 830 and 331 up- and down-regulated m6A peaks, (corresponding to 463 and 243 up- and down-regulated circRNAs, respectively), were identified in HCASMCs in a pathological condition. Functional analysis suggested that these circRNAs appeared to participate in intracellular protein, histone deacetylase complex, ATP-dependent activity, autophagy, and AMPK signaling pathway. Four candidate circRNAs were selected for further evaluation in HCASMCs and human samples. The results suggested that hsa_circHECTD1 and hsa_circZBTB46 were significantly increased in patients with CAD (p-value = 0.039 and p-value = 0.014) and may act as potential diagnostic biomarkers of CAD. Furthermore, statistical results showed that hsa_circHECTD1 and hsa_circSEC62 were positively correlated with triglyceride (TG) (r = 0.213, p-value = 0.014) and Gensini Score (used to quantify the severity of CAD) (r = 0.349, p-value <0.001), respectively. Logistic regression revealed that hsa_circZBTB46 was strongly correlated with the incidence of CAD, and the synergistic effects of circRNAs and hypertension enhanced the risk of CAD. These results show that hsa_circHECTD1 and hsa_circZBTB46 may be new targets for further studies, and this study enhances our understanding of the effects of m6A-circRNAs on the pathogenesis of CAD.

Laquinimod Inhibits Microglial Activation, Astrogliosis, BBB Damage, and Infarction and Improves Neurological Damage after Ischemic Stroke

Glial activation is involved in neuroinflammation and blood-brain barrier (BBB) damage, which plays a key role in ischemic stroke-induced neuronal damage; therefore, regulating glial activation is an important way to inhibit ischemic brain injury. Effects of laquinimod (LAQ) include inhibiting axonal damage and neuroinflammation in multiple neuronal injury diseases. However, whether laquinimod can exert neuroprotective effects after ischemic stroke remains unknown. In this study, we investigated the effect of LAQ on glial activation, BBB damage, and neuronal damage in an ischemic stroke model. Adult ICR mice were used to create a photothrombotic stroke (PT) model. LAQ was administered orally at 30 min after ischemic injury. Neurobehavioral tests, Evans Blue, immunofluorescence, TUNEL, Nissl staining, and western blot were performed to evaluate the neurofunctional outcome. Quantification of immunofluorescence was evaluated by unbiased stereology. LAQ post-treatment significantly reduced infarction and improved forepaw function at 5 days after PT. Interestingly, LAQ treatment significantly promoted anti-inflammatory microglial activation. Moreover, LAQ treatment reduced astrocyte activation, glial scar formation, and BBB breakdown in ischemic brains. Therefore, this study demonstrated that LAQ post-treatment restricted microglial polarization, astrogliosis, and glial scar and improved BBB damage and behavioral function. LAQ may serve as a novel target to develop new therapeutic agents for ischemic stroke.

Circular RNA-mediated ceRNA network was identified in human lung adenocarcinoma by high-throughput sequencing

OBJECTIVES

Aberrantly expressed circular RNAs (circRNAs) have been detected in many types of tumors. Hence, they are currently investigated as candidate biomarkers for diagnostic and potential targets for therapy in cancers. The objective of this study was to assess the expression profile of circRNA in lung adenocarcinoma (LUAD).

METHODS

This study included 14 pairs of postoperative lung adenocarcinoma specimens, including cancer tissues and matched adjacent tissues. Second-generation sequencing was applied to the specimens to determine the circRNA expression in them among the 5242 distinct circRNAs detected.

RESULTS

We identified a total of 18 significantly dysregulated circRNAs in the LUAD tissues: upregulation in four and downregulation in 14. ROC (The receiver operating characteristic curve) further suggested that hsa_circ_0120106, has_circ_0007342, has_circ_0005937, and circRNA_0000826 could potentially be used as biomarkers in the diagnosis of LUAD. Furthermore, study of the circRNA-microRNA (miRNA)-messenger RNA (mRNA) revealed interactions between the 18 dysregulated circRNA and several cancer-related miRNAs. Finally, a further Kyoto Encyclopedia of Genes and Genomes analysis showed that the cell cycle phase transition, p53 signaling pathway, AMP-activated protein kinase (AMPK) relative signaling pathway, and so on were key putative pathways in the process of LUAD.

CONCLUSIONS

These findings demonstrated the correlation between abnormality in circRNA expression and LUAD, which lays the foundation of making CircRNAs candidate biomarkers in the diagnosis of LUAD.

Hypericin Ameliorates Depression-like Behaviors via Neurotrophin Signaling Pathway Mediating m6A Epitranscriptome Modification

Hypericin, one of the major antidepressant constituents of St. John's wort, was shown to exert antidepressant effects by affecting cerebral CYP enzymes, serotonin homeostasis, and neuroinflammatory signaling pathways. However, its exact mechanisms are unknown. Previous clinical studies reported that the mRNA modification N6-methyladenosine (m6A) interferes with the neurobiological mechanism in depressed patients, and it was also found that the antidepressant efficacy of tricyclic antidepressants (TCAs) is related to m6A modifications. Therefore, we hypothesize that the antidepressant effect of hypericin may relate to the m6A modification of epitranscriptomic regulation. We constructed a UCMS mouse depression model and found that hypericin ameliorated depressive-like behavior in UCMS mice. Molecular pharmacology experiments showed that hypericin treatment upregulated the expression of m6A-modifying enzymes METTL3 and WTAP in the hippocampi of UCMS mice. Next, we performed MeRIP-seq and RNA-seq to study m6A modifications and changes in mRNA expression on a genome-wide scale. The genome-wide m6A assay and MeRIP-qPCR results revealed that the m6A modifications of Akt3, Ntrk2, Braf, and Kidins220 mRNA were significantly altered in the hippocampi of UCMS mice after stress stimulation and were reversed by hypericin treatment. Transcriptome assays and qPCR results showed that the Camk4 and Arhgdig genes might be related to the antidepressant efficacy of hypericin. Further gene enrichment results showed that the differential genes were mainly involved in neurotrophic factor signaling pathways. In conclusion, our results show that hypericin upregulates m6A methyltransferase METTL3 and WTAP in the hippocampi of UCMS mice and stabilizes m6A modifications to exert antidepressant effects via the neurotrophin signaling pathway. This suggests that METTL3 and WTAP-mediated changes in m6A modifications may be a potential mechanism for the pathogenesis of depression and the efficacy of antidepressants, and that the neurotrophin signaling pathway plays a key role in this process.

Acute and Sub-chronic Anticonvulsant Effects of Edaravone on Seizure Induced by Pentylenetetrazole or Electroshock in Mice, Nitric Oxide Involvement

Background

Edaravone is an anti-stroke medication that may have nitric oxide (NO) modulating properties. This study evaluated the role of NO in the acute and sub-chronic anticonvulsant effects of edaravone in murine models of seizures induced by intraperitoneal (IP) or intravenous (IV) injections of pentylenetetrazole (PTZ) or electroshock (maximal electroshock seizure [MES]).

Methods

132 male albino mice were randomly divided into 22 groups (n=6) and given IP injections of vehicle or edaravone either acutely or for eight days (sub-chronically). The seizure was induced by electroshock or PTZ (IP or IV). The following edaravone doses were used: 7.5, 10, 12.5 (acute); 5, 7.5, 10 (sub-chronic) in IP PTZ model; 5, 7.5, 10 in IV PTZ model; and 5, 10 mg/Kg in the MES. To evaluate NO involvement, 216 mice were randomly divided into 36 groups (n=6) and pretreated with vehicle, edaravone, a non-specific nitric oxide synthase (NOS) inhibitor: N(ω)-nitro-L-arginine methyl ester (L-NAME) (5 mg/Kg), a specific nNOS inhibitor: 7-nitroindazole (7-NI) (60 mg/Kg), or a combination of edaravone plus L-NAME or 7-NI, either acutely or for eight days before seizure induction. Doses of edaravone were as follows: in IP PTZ model: 12.5 (acute) and 10 (sub-chronic); in IV PTZ model: 10; and in the MES: 5 mg/Kg. Data were analyzed using the one-way analysis of variance (ANOVA) followed by Tukey's test (SPSS 18). P≤0.05 was considered statistically significant.

Results

In the IP PTZ model, edaravone increased time latencies to seizures (P<0.001), prevented tonic seizures, and death. Edaravone increased the seizure threshold (P<0.001) in the IV PTZ model and shortened the duration of tonic hind-limb extension (THE) in the MES model (P<0.001). In comparison to mice treated with edaravone alone, adding L-NAME or 7-NI reduced seizure time latencies (P<0.001), reduced seizure threshold (P<0.001), and increased THE duration (P<0.001).

Conclusion

Edaravone (acute or sub-chronic) could prevent seizures by modulating NO signaling pathways.

Assessment of silicone wristbands for monitoring personal exposure to chlorinated paraffins (C8-36): A pilot study

Chlorinated paraffins (CPs) are a major environmental concern due to their ubiquitous presence in the environment. Since human exposure to CPs can significantly differ among individuals, it is essential to have an effective tool for monitoring personal exposure to CPs. In this pilot study, silicone wristbands (SWBs) were employed as a personal passive sampler to measure time-weighted average exposure to CPs. Twelve participants were asked to wear a pre-cleaned wristband for a week during the summer of 2022, and three field samplers (FSs) in different micro-environments were also deployed. The samples were then analyzed for CP homologs by LC-Q-TOFMS. In worn SWBs, the median concentrations of quantifiable CP classes were 19 ng/g wb, 110 ng/g wb, and 13 ng/g wb for ∑SCCPs, ∑MCCPs, and ∑LCCPs (C_18-20), respectively. For the first time, lipid content is reported in worn SWBs, which could be a potential impact factor in the kinetics of the accumulation process for CPs. Results showed that micro-environments were key contributors to dermal exposure to CPs, while a few outliers suggested other sources of exposure. CP exposure via dermal contact showed an increased contribution and thus poses a nonnegligible potential risk to humans in daily life. Results presented here provide proof of concept of the use of SWBs as a cheap and non-invasive personal sampler in exposure studies.

The Role of Circular RNAs in Ischemic Stroke

Ischemic stroke (IS), a devastating condition characterized by intracranial artery stenosis and middle cerebral artery occlusion leading to insufficient oxygen supply to the brain, is a major cause of death and physical disability worldwide. Recent research has demonstrated the critical role of circular RNAs (circRNAs), a class of covalently enclosed noncoding RNAs that are widespread in eukaryotic cells, in regulating various physiological and pathophysiological cellular processes, including cell apoptosis, autophagy, synaptic plasticity, and neuroinflammation. In the past few years, circRNAs have attracted extensive attention in the field of IS research. This review summarizes the current understanding of the mechanisms underlying the involvement of circRNAs in IS development. A better understanding of circRNA-mediated pathogenic mechanisms in IS may pave the way for translating circRNA research into clinical practice, ultimately improving the clinical outcomes of IS patients.

Extracellular Vesicles Derived from Bone Mesenchymal Stem Cells Carrying circ_0000075 Relieves Cerebral Ischemic Injury by Competitively Inhibiting miR-218-5p and Up-regulating E3 Ubiquitin Ligase SMURF2

Extracellular vesicle (EV)-encapsulated circRNAs have the potential role in affecting brain disorders. However, the role of circ_0000075 in cerebral ischemic injury remains unclear. Here, we tried to investigate the mechanism of bone marrow mesenchymal stem cell (BMSC)-derived EVs carrying circ_0000075 in the control of cerebral ischemic injury. Initially, a mouse model with cerebral ischemic injury was induced by middle cerebral artery occlusion (MCAO), followed by the determination of circ_0000075 expression. Then, neurons were isolated and subjected to oxygen-glucose deprivation/reperfusion. BMSCs were isolated for extraction of EVs. The correlation among circ_0000075, microRNA (miR)-218-5p, and Smad ubiquitination regulatory factor 2 (SMURF2) was detected with their roles in cerebral ischemic injury analyzed in vivo and in vitro. circ_0000075 was down-regulated in MCAO mice and engineered RVG-EVs were internalized by neurons to up-regulate circ_0000075 expression. Treatment of RVG-circ_0000075-EVs reduced brain tissue damage, increased neuronal count, and significantly curtailed apoptosis rate, suppressing cerebral ischemic injury in vitro and in vivo. miR-218-5p was targeted by circ_0000075 in neurons, which promoted SMURF2 expression. A negative correlation between SMURF2 and transcriptional regulator Yin Yang 1 (YY1) was identified. In vitro experiments further proved that circ_ 00,000 75 could down-regulate the expression of YY1 through SMURF2, and finally relieving cerebral ischemic injury. Collectively, engineered EVs delivered circ_0000075 into brain tissues and increased circ_0000075 expression, which down-regulated miR-218-5p and up-regulated SMURF2, thus alleviating cerebral ischemic injury.

Circular RNA as biomarkers for acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Rapid diagnosis of acute ischemic stroke (AIS) patients is still challenging, and reliable biomarkers are needed. Noncoding RNAs are important for many physiological activities, among which circular RNAs (circRNAs) have been proven to be more tissue-specific and conservative. Many recent studies found the potential of circRNAs as biomarkers for many diseases, including cardiovascular diseases, cancers, and ischemic stroke. This systemic review and meta-analysis aimed to identify circRNAs as potential biomarkers for AIS.

METHODS

This study has been prospectively registered in PROSPERO (Registration No. 11 CRD42021288033). Published literature comparing circRNA expression profiles between AIS and non-AIS in human and animal models were retrieved from the articles published by January 2023 in major databases. We descriptively summarized the included studies, conducted meta-analysis under a random effects model, and did bioinformatics analysis including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis.

RESULTS

Totally 23 studies were included, reporting 18 distinctive upregulated and 20 distinctive downregulated circRNAs. Diagnostic meta-analysis indicated discriminative ability of the circRNAs. Furthermore, circRNA HECTD1, circRNA DLGAP4, circRNA CDC14A, circRNA SCMH1, and circRNA TLK1 were reported with the same regulation trend in more than one study (animal studies included). GO and KEGG enrichment analyses indicated that the target genes of these five circRNAs were enriched in regulating cell proliferation, apoptosis, and oxidative stress.

CONCLUSIONS

This study demonstrates that circRNAs (circRNA HECTD1, circRNA DLGAP4, circRNA CDC14A, circRNA SCMH1, and circRNA TLK1) generally are promising as potential biomarkers for AIS. However, due to the limited number of studies, diagnostic value of individual circRNA could not be validated. More in vitro and in vivo functional studies are needed.

Overexpression of GPX4 attenuates cognitive dysfunction through inhibiting hippocampus ferroptosis and neuroinflammation after traumatic brain injury

Ferroptosis is a newly discovered form of regulated cell death that is triggered primarily by lipid peroxidation. A growing body of evidence has implicated ferroptosis in the pathophysiology of traumatic brain injury (TBI). However, none of these studies focused its role on TBI-induced hippocampal injury. Here, we demonstrated that the distinct ferroptotic signature was detected in the injured hippocampus at the early stage of TBI. Besides, a prominent pro-ferroptosis environment was detected in the ipsilateral hippocampus after TBI, including elevated levels of arachidonic acid (AA), ACLS4, and ALXO15, and deficiency of GPX4. Subsequently, we used AAV-mediated Gpx4 overexpression to counteract ferroptosis in the hippocampus, and found that TBI-induced cognitive deficits were significantly alleviated after Gpx4 overexpression. Biochemical results also confirmed that TBI-induced hippocampal ferroptosis and synaptic damage were partially reversed by Gpx4 overexpression. In addition, Gpx4 overexpression inhibited TBI-induced neuroinflammation and peripheral macrophage infiltration. Interestingly, the results of transwell migration assay showed that ferroptotic neurons increased CCL2 expression and promoted iBMDM cell migration. However, this effect was inhibited by CCL2 antagonist, RS102895. These data suggested that inhibition of ferroptosis may be as a potential strategy to ameliorate TBI-induced cognitive deficits through blockade of hippocampal ferroptosis and neuroinflammation.

Palmitic acid-induced microRNA-143-5p expression promotes the epithelial-mesenchymal transition of retinal pigment epithelium via negatively regulating JDP2

BACKGROUND

The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is the most crucial step in the etiopathogenesis of proliferative vitreoretinopathy. This study aimed to investigate the role of miR-143-5p in the EMT of RPE cells induced by palmitic acid (PA).

METHODS

ARPE-19 cells were treated with PA to induce EMT, followed by E-cadherin and α-smooth muscle actin (α-SMA) expression and the microRNA expression profile analyses. Subsequently, miR-143-5p mimics/inhibitors, and plasmids expressing its predicted target gene c-JUN-dimerization protein 2 (JDP2), were transfected in ARPE-19 cells using lipofectamine 3000, and followed by PA treatment. Their impacts on EMT were explored using wound healing and Western blot assays. Additionally, miR-143-5p mimics and JDP2-expressing plasmid were co-transfected into ARPE-19 cells and treated with PA to explore whether PA induced EMT of ARPE-19 cells via the miR-143-5p/JDP2 axis.

RESULTS

PA decreased E-cadherin expression and increased those of α-SMA and miR-143-5p. Inhibiting miR-143-5p suppressed the migration of ARPE-19 cells and altered the expressions of E-cadherin and α-SMA. However, additional PA treatment attenuated these alterations. JDP2 was a target of miR-143-5p. Overexpression of JDP2 inhibited the EMT of ARPE-19 cells, resulting in α-SMA downregulation and E-cadherin upregulation, which were reversed by additional PA treatment via inhibiting JDP2 expression. Overexpression of miR-143-5p reversed the effect of JDP2 on the EMT of ARPE-19 cells and additional PA treatment markedly enhanced the effect of miR-143-5p mimics.

CONCLUSION

PA promotes EMT of ARPE-19 cells via regulating the miR-143-5p/JDP2 axis, and these findings provide significant insights into the potential targeting of this axis to treat proliferative vitreoretinopathy.

Circ_0067934 as a novel therapeutic target in cancer: From mechanistic to clinical perspectives

Circular RNAs, as a type of non-coding RNAs, are identified in a various cell. Circular RNAs have stable structures, conserved sequence, and tissue and cell-specific level. High throughput technologies have proposed that circular RNAs act via various mechanisms like sponging microRNAs and proteins, regulating transcription factors, and scaffolding mediators. Cancer is one of the major threat for human health. Emerging data have proposed that circular RNAs are dysregulated in cancers as well as are associated with aggressive behaviors of cancer -related behaviors like cell cycle, proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT). Among them, circ_0067934 was shown to act as an oncogene in cancers to enhance migration, invasion, proliferation, cell cycle, EMT, and inhibit cell apoptosis. In addition, these studies have proposed that it could be a promising diagnostic and prognostic biomarker in cancer. This study aimed to review the expression and molecular mechanism of circ_0067934 in modulating the malignant behaviors of cancers as well as to explore its potential as a target in cancer chemotherapy, diagnosis, prognosis and treatment.

Regulation of self-renewal in ovarian cancer stem cells by fructose via chaperone-mediated autophagy

The chaperone-mediated autophagy (CMA) pathway is deregulated in different types of cancers; however, its role in cancer stem cells (CSCs) is unknown yet. Development of ovarian cancer, the most lethal gynecological type of cancer, involves the metastasis of CSCs to the abdominal cavity. This study aims to determine the role of CMA in ovarian CSCs. We found that the transcription factor EB (TFEB) and trehalose, a disaccharide that induces TFEB activation, enhance the expression of octamer-binding transcription factor 4 (OCT4) stem cell and lysosomal-associated membrane protein 2A (LAMP2A) CMA markers. However, trehalose did not increase the level of the LC3II macroautophagy marker in ovarian CSCs. In A2780 and SKOV3 ovarian CSCs, LAMP2A and heat shock protein 70 (HSC70) exhibited higher expression levels than in normal adherent cells. Our results showed that the silencing of the LAMP2A gene resulted in reduced sphere formation and enhanced GLUT5 expression in ovarian CSCs. Moreover, the treatment with fructose reduced sphere formation and enhanced the expression levels of LAMP2A, SOX2, and OCT4 in ovarian CSCs. The KEGG functional analysis revealed that differentially expressed genes were enriched in the ferroptosis pathway in A2780-spheroid (SP) cells after treatment with fructose. In A2780-SP and SKOV3-SP cells, the level of SLC7A11 decreased whereas FTH increased after treatment with fructose. Taken together, our results suggest that CMA is mediated in CSCs via fructose metabolism.

Molecular insights into the pathogenic impact of vitamin D deficiency in neurological disorders

Neurological disorders are the major cause of disability, leading to a decrease in quality of life by impairing cognitive, sensorimotor, and motor functioning. Several factors have been proposed in the pathogenesis of neurobehavioral changes, including nutritional, environmental, and genetic predisposition. Vitamin D (VD) is an environmental and nutritional factor that is widely distributed in the central nervous system's subcortical grey matter, neurons of the substantia nigra, hippocampus, thalamus, and hypothalamus. It is implicated in the regulation of several brain functions by preserving neuronal structures. It is a hormone rather than a nutritional vitamin that exerts a regulatory role in the pathophysiology of several neurological disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and multiple sclerosis. A growing body of epidemiological evidence suggests that VD is critical in neuronal development and shows neuroprotective effects by influencing the production and release of neurotrophins, antioxidants, immunomodulatory, regulation of intracellular calcium balance, and direct effect on the growth and differentiation of nerve cells. This review provides up-to-date and comprehensive information on vitamin D deficiency, risk factors, and clinical and preclinical evidence on its relationship with neurological disorders. Furthermore, this review provides mechanistic insight into the implications of vitamin D and its deficiency on the pathogenesis of neurological disorders. Thus, an understanding of the crucial role of vitamin D in the neurobiology of neurodegenerative disorders can assist in the better management of vitamin D-deficient individuals.

The Potential Biological Roles of Circular RNAs in the Immune Systems of Insects to Pathogen Invasion

Circular RNAs (circRNAs) are a newly discovered class of endogenously expressed non-coding RNAs (ncRNAs). They are highly stable, covalently closed molecules that frequently exhibit tissue-specific expression in eukaryotes. A small number of circRNAs are abundant and have been remarkably conserved throughout evolution. Numerous circRNAs are known to play important biological roles by acting as microRNAs (miRNAs) or protein inhibitors ('sponges'), by regulating the function of proteins, or by being translated themselves. CircRNAs have distinct cellular functions due to structural and production differences from mRNAs. Recent advances highlight the importance of characterizing circRNAs and their targets in a variety of insect species in order to fully understand how they contribute to the immune responses of these insects. Here, we focus on the recent advances in our understanding of the biogenesis of circRNAs, regulation of their abundance, and biological roles, such as serving as templates for translation and in the regulation of signaling pathways. We also discuss the emerging roles of circRNAs in regulating immune responses to various microbial pathogens. Furthermore, we describe the functions of circRNAs encoded by microbial pathogens that play in their hosts.

Recent advances and application value of circRNA in neuroblastoma

Neuroblastoma (NB) is children’s most prevalent solid malignant tumor, accounting for 15% of childhood cancer mortality. Non-coding RNA is important in NB pathogenesis. As a newly identified non-coding RNA, abnormal regulation (abnormal up-regulation or down-regulation) of the circRNAs expression is implicated in the tumorigenesis of various tumors, including NB. CircRNAs primarily regulate the expression of microRNA (miRNA) target genes by microRNA (miRNA) sponge adsorption. Clinical evidence suggests that the expression of certain circRNAs is associated with the prognosis and clinical features of NB and hence may be exploited as a biomarker or therapeutic target. This review examines circRNAs that have been demonstrated to play a function in NB.

The autophagy in ischemic stroke: A regulatory role of non-coding-RNAs

Ischemic stroke (IS) is a central nervous system neurological disorder ascribed to an acute focal trauma, with high mortality and disability, leading to a heavy burden on family and society. Autophagy is a self-digesting process by which damaged organelles and useless proteins are recycled to maintain cellular homeostasis, and plays a pivotal role in the process of IS. Non-coding RNAs (ncRNAs), mainly contains microRNA, long non-coding RNA and circular RNA, have been extensively investigated on regulation of autophagy in human diseases. Recent studies have implied that ncRNAs-regulating autophagy participates in pathophysiological process of IS, including cell apoptosis, inflammation, oxidative stress, blood-brain barrier damage and glial activation, which indicates that regulating autophagy by ncRNAs may be beneficial for IS treatment. This review summarizes the role of autophagy in IS, as well as focuses on the role of ncRNAs-mediated autophagy in IS, for the development of potential therapeutic strategies in this disease.

CircSYNDIG1 ameliorates stress-induced abnormal behaviors by suppressing miR-344-5p in mice

Circular RNA (circRNA) plays an important role in diverse stress-related neuropsychiatric disorders like depression, anxiety and cognitive disorders. Here, using a circRNA microarray, we found that circSYNDIG1, an unreported circRNA, was significantly downregulated in the hippocampus of chronic unpredictable mild stress (CUMS) mice and further validated this finding in corticosterone (CORT) and lipopolysaccharide (LPS) mice by qRT-PCR, and it was negatively correlated with depressive- and anxiety-like behaviors of these three stressed mice. Furthermore, the interaction of miR-344-5p and circSYNDIG1 was confirmed by in situ hybridization (FISH) assay in hippocampus and dual luciferase reporter assay in 293 T cells. And miR-344-5p mimics could simulate the dendritic spine density reduction, depressive- and anxiety-like behaviors and memory impairment induced by CUMS. Overexpression of circSYNDIG1 in hippocampus significantly ameliorated these abnormal changes induced by CUMS or miR-344-5p. It indicated that circSYNDIG1 functions as an miR-344-5p sponge to inhibit miR-344-5p impact, resulting in the increase of dendritic spine density and the subsequent amelioration of the abnormal behaviors. Therefore, the downregulation of circSYNDIG1 in hippocampus participates in CUMS-induced depressive and anxiety-like behavior of mice though miR-344-5p. These findings represent the first evidence for the involvement of circSYNDIG1 and its coupling mechanism in depression and anxiety, suggesting that circSYNDIG1 and miR-344-5p might be new targets for the treatment of stress-related disorder.

Tiagabine suppresses pentylenetetrazole-induced seizures in mice and improves behavioral and cognitive parameters by modulating BDNF/TrkB expression and neuroinflammatory markers

Tiagabine (Tia), a new-generation antiseizure drug that mimics the GABAergic signaling by inhibiting GABA transporter type-1, is the least studied molecule in chronic epilepsy models with comorbid neurobehavioral and neuroinflammatory parameters. Therefore, the current study investigated the effects of Tia in a real-time manner on electroencephalographic (EEG) activity, behavioral manifestations and mRNA expression in pentylenetetrazole (PTZ)-kindled mice. Male BALB/c mice were treated with tiagabine (0.5, 1 and 2 mg/kg) for 21 days with simultaneous PTZ (40 mg/kg) injection every other day for a total of 11 injections and monitored for seizure progression with synchronized validation through EEG recordings from cortical electrodes. The post-kindling protection from anxiety and memory deficit was verified by a battery of behavioral experiments. Isolated brains were evaluated for oxidative alterations and real-time changes in mRNA expression for BDNF/TrkB, GAT-1 and GAT-3 as well as neuroinflammatory markers. Experimental results revealed that Tia at the dose of 2 mg/kg maximally inhibited the development of full bloom seizure and reduced epileptic spike discharges from the cortex. Furthermore, Tia dose-dependently exerted the anxiolytic effects and protected from PTZ-evoked cognitive impairment. Tia reduced lipid peroxidation and increased superoxide dismutase and glutathione levels in the brain via augmentation of GABAergic modulation. PTZ-induced upregulated BDNF/TrkB signaling and pro-inflammatory cytokines were mitigated by Tia with upregulation of GAT-1 and GAT-3 transporters in whole brains. In conclusion, the observed effects of Tia might have resulted from reduced oxidative stress, BDNF/TrkB modulation and mitigated neuroinflammatory markers expression leading to reduced epileptogenesis and improved epilepsy-related neuropsychiatric effects.

CircRNAs and RNA-Binding Proteins Involved in the Pathogenesis of Cancers or Central Nervous System Disorders

Circular RNAs (circRNAs), a newly recognized group of noncoding RNA transcripts, have established widespread attention due to their regulatory role in cell signaling. They are covalently closed noncoding RNAs that form a loop, and are typically generated during the splicing of precursor RNAs. CircRNAs are key post-transcriptional and post-translational regulators of gene expression programs that might influence cellular response and/or function. In particular, circRNAs have been considered to function as sponges of specific miRNA, regulating cellular processes at the post-transcription stage. Accumulating evidence has shown that the aberrant expression of circRNAs could play a key role in the pathogenesis of several diseases. Notably, circRNAs, microRNAs, and several RNA-binding proteins, including the antiproliferative (APRO) family proteins, could be indispensable gene modulators, which might be strongly linked to the occurrence of diseases. In addition, circRNAs have attracted general interest for their stability, abundance in the brain, and their capability to cross the blood-brain barrier. Here, we present the current findings and theragnostic potentials of circRNAs in several diseases. With this, we aim to provide new insights to support the development of novel diagnostic and/or therapeutic strategies for these diseases.

The role of microRNAs in depression

Major depressive disorder (MDD) is a psychiatric disorder with increasing prevalence worldwide. It is a leading cause of disability and suicide, severely affecting physical and mental health. However, the study of depression remains at an exploratory stage in terms of diagnostics and treatment due to the complexity of its pathogenesis. MicroRNAs are endogenous short-stranded non-coding RNAs capable of binding to the 3’untranslated region of mRNAs. Because of their ability to repress translation process of genes and are found at high levels in brain tissues, investigation of their role in depression has gradually increased recently. This article summarizes recent research progress on the relationship between microRNAs and depression. The microRNAs play a regulatory role in the pathophysiology of depression, involving dysregulation of monoamines, abnormalities in neuroplasticity and neurogenesis, hyperactivity of the HPA axis, and dysregulation of inflammatory responses. These microRNAs might provide new clue for the diagnosis and treatment of MDD, and the development of antidepressant drugs.

Potential Roles of m6A and FTO in Synaptic Connectivity and Major Depressive Disorder

RNA modifications known as epitranscriptomics have emerged as a novel layer of transcriptomic regulation. Like the well-studied epigenetic modifications characterized in DNA and on histone-tails, they have been shown to regulate activity-dependent gene expression and play a vital role in shaping synaptic connections in response to external stimuli. Among the hundreds of known RNA modifications, N6-methyladenosine (m6A) is the most abundant mRNA modification in eukaryotes. Through recognition of its binding proteins, m6A can regulate various aspects of mRNA metabolism and is essential for maintaining higher brain functions. Indeed, m6A is highly enriched in synapses and is involved in neuronal plasticity, learning and memory, and adult neurogenesis. m6A can also respond to environmental stimuli, suggesting an important role in linking molecular and behavioral stress. This review summarizes key findings from fields related to major depressive disorder (MDD) including stress and learning and memory, which suggest that activity-dependent m6A changes may, directly and indirectly, contribute to synaptic connectivity changes underlying MDD. Furthermore, we will highlight the roles of m6A and FTO, a m6A eraser, in the context of depressive-like behaviors. Although we have only begun to explore m6A in the context of MDD and psychiatry, elucidating a link between m6A and MDD presents a novel molecular mechanism underlying MDD pathogenesis.

PPARα Inhibits Astrocyte Inflammation Activation by Restoring Autophagic Flux after Transient Brain Ischemia

Astrocyte inflammation activation is an important cause that hinders the recovery of motor function after cerebral ischemia. However, its molecular mechanism has not yet been clearly clarified. The peroxisome proliferator-activated receptor α (PPARα) is a ligand-activated nuclear transcriptional factor. This study aims to further clarify the role of PPARα in astrocyte inflammation activation after cerebral ischemia and to explore the underlying mechanism. Astrocyte activation was induced in an in vivo model by transient middle cerebral artery occlusion (tMCAO) in mice. The in vitro model was induced by an oxygen-glucose deprivation/reoxygenation (OGD/R) in a primary culture of mouse astrocyte. PPARα-deficient mice were used to observe the effects of PPARα on astrocyte activation and autophagic flux. Our results showed that PPARα was mainly expressed in activated astrocytes during the chronic phase of brain ischemia and PPARα dysfunction promoted astrocyte inflammatory activation. After cerebral ischemia, the expressions of LC3-II/I and p62 both increased. Autophagic vesicle accumulation was observed by electron microscopy in astrocytes, and the block of autophagic flux was indicated by an mRFP-GFP-LC3 adenovirus infection assay. A PPARα deficit aggravated the autophagic flux block, while PPARα activation preserved the lysosome function and restored autophagic flux in astrocytes after OGD/R. The autophagic flux blocker bafilomycin A1 and chloroquine antagonized the effect of the PPARα agonist on astrocyte activation inhibition. This study identifies a potentially novel function of PPARα in astrocyte autophagic flux and suggests a therapeutic target for the prevention and treatment of chronic brain ischemic injury.

The significance of N6-methyladenosine-modified non-coding RNAs in different disorders

N6-methyladenosine (m6A) is the most widespread endogenous modification affecting the expression of eukaryotic mRNA transcripts. Recent studies have shown that the m6A marks within non-coding RNAs can affect their functions and expression in a manner similar to that of mRNA-coding genes. Since non-coding RNAs are involved in the pathophysiology of several disorders, identification of the role of m6A marks in the regulation of expression of non-coding RNAs can open a new era for identifying underlying mechanisms of several disorders and designing novel therapeutic modalities for a variety of disorders, particularly cancers. Moreover, a number of non-coding RNAs can affect m6A levels. In the current review, we discuss the impacts of m6A marks on the expression of non-coding RNAs in the context of different disorders, such as bone, gastrointestinal, neurologic, renal, pulmonary, hepatic and other disorders.

Circular RNA CircPDS5B impairs angiogenesis following ischemic stroke through its interaction with hnRNPL to inactivate VEGF-A

BACKGROUND

Ischemic stroke (IS) is the primary cause of mortality and disability worldwide. Circular RNAs (circRNAs) have been proposed as crucial regulators in IS. This study focused on the role of circPDS5B in IS and its underlying mechanism.

METHOD

Transient middle cerebral artery occlusion (tMCAO) mice and glucose deprivation/reoxygenation (OGD/R)-exposed human brain microvascular endothelial cells (BMECs) were used as IS models. Expression levels of circPDS5B, heterogenous nuclear ribonucleoprotein L (hnRNPL), runt-related transcription factor-1 (Runx1), and Zinc finger protein 24 (ZNF24) were quantified by qRT-PCR. MTT, wound healing, transwell and tube formation assays were employed to evaluate the cell proliferation, migration, and angiogenesis, respectively. Moreover, RNA pull-down, and RIP assay were performed to investigate the interaction among circPDS5B, hnRNPL and vascular endothelial growth factor-A (VEGFA).

RESULTS

circPDS5B was significantly up-regulated in IS patients and tMCAO mice. Deficiency of circPDS5B relieved brain infarction and neuronal injury of tMCAO mice. OGD/R-induced apoptosis, inhibition in viability, migration, and angiogenesis in BMECs were dramatically abrogated by circPDS5B knockdown. Mechanistically, circPDS5B stabilized Runx1 and ZNF24 via recruiting hnRNPL, thereby suppressing the transcription and expression of VEGFA. hnRNPL silencing strengthened circPDS5B knockdown-mediated beneficial effect on IS.

CONCLUSION

Altogether, our study showed that high expression of circPDS5B exacerbated IS through recruitment of hnRNP to stabilize Runx1/ZNF24 and subsequently inactivate VEGF-A. Our findings suggest circPDS5B may be a novel therapeutic target for IS.

Hypoxia-responsive circular RNA circAAGAB reduces breast cancer malignancy by activating p38 MAPK and sponging miR-378 h

BACKGROUND

Breast cancer is a prevalent disease in women, with high prevalence worldwide. The hypoxic microenvironment of solid tumors develops during the progress of carcinogenesis and leads to greater malignancy and treatment resistance. Recently, accumulating evidence indicates that non-coding RNAs, such as circular RNAs (circRNAs), play a pivotal role in altering cellular functions. However, the underlying mechanisms of circRNAs in breast cancer are still unclear. Therefore, the purpose of this study was to investigate the role of a tumor-suppressive circRNA, circAAGAB, in breast cancer by assuming down-regulation of circAAGAB under hypoxia and the properties of a tumor suppressor.

METHODS

Firstly, circAAGAB was identified from expression profiling by next generation sequencing. Next, the stability of circAAGAB increased by interacting with the RNA binding protein FUS. Moreover, cellular and nuclear fractionation showed that most circAAGAB resided in the cytoplasm and that it up-regulated KIAA1522, NKX3-1, and JADE3 by sponging miR-378 h. Lastly, the functions of circAAGAB were explored by identifying its down-stream genes using Affymetrix microarrays and validated by in vitro assays.

RESULTS

The results showed that circAAGAB reduced cell colony formation, cell migration, and signaling through p38 MAPK pathway, as well as increased radiosensitivity.

CONCLUSION

These findings suggest that the oxygen-responsive circAAGAB acts as a tumor suppressor in breast cancer, and may contribute to the development of a more specific therapeutic regimen for breast cancer.

Single-cell RNA sequencing reveals cell landscape following antimony exposure during spermatogenesis in Drosophila testes

Antimony (Sb), is thought to induce testicular toxicity, although this remains controversial. This study investigated the effects of Sb exposure during spermatogenesis in the Drosophila testis and the underlying transcriptional regulatory mechanism at single-cell resolution. Firstly, we found that flies exposed to Sb for 10 days led to dose-dependent reproductive toxicity during spermatogenesis. Protein expression and RNA levels were measured by immunofluorescence and quantitative real-time PCR (qRT-PCR). Single-cell RNA sequencing (scRNA-seq) was performed to characterize testicular cell composition and identify the transcriptional regulatory network after Sb exposure in Drosophila testes. scRNA-seq analysis revealed that Sb exposure influenced various testicular cell populations, especially in GSCs_to_Early_Spermatogonia and Spermatids clusters. Importantly, carbon metabolism was involved in GSCs/early spermatogonia maintenance and positively related with SCP-Containing Proteins, S-LAPs, and Mst84D signatures. Moreover, Seminal Fluid Proteins, Mst57D, and Serpin signatures were highly positively correlated with spermatid maturation. Pseudotime trajectory analysis revealed three novel states for the complexity of germ cell differentiation, and many novel genes (e.g., Dup98B) were found to be expressed in state-biased manners during spermatogenesis. Collectively, this study indicates that Sb exposure negatively impacts GSC maintenance and spermatid elongation, damaging spermatogenesis homeostasis via multiple signatures in Drosophila testes and therefore supporting Sb-mediated testicular toxicity.

HIPK2 in Angiogenesis: A Promising Biomarker in Cancer Progression and in Angiogenic Diseases

Angiogenesis is the formation of new blood capillaries taking place from preexisting functional vessels, a process that allows cells to cope with shortage of nutrients and low oxygen availability. Angiogenesis may be activated in several pathological diseases, from tumor growth and metastases formation to ischemic and inflammatory diseases. New insights into the mechanisms that regulate angiogenesis have been discovered in the last years, leading to the discovery of new therapeutic opportunities. However, in the case of cancer, their success may be limited by the occurrence of drug resistance, meaning that the road to optimize such treatments is still long. Homeodomain-interacting protein kinase 2 (HIPK2), a multifaceted protein that regulates different molecular pathways, is involved in the negative regulation of cancer growth, and may be considered a "bona fide" oncosuppressor molecule. In this review, we will discuss the emerging link between HIPK2 and angiogenesis and how the control of angiogenesis by HIPK2 impinges in the pathogenesis of several diseases, including cancer.

Systematic Analysis of RNA Expression Profiles in Different Ischemic Cortices in MCAO Mice

The prognosis of ischemic stroke patients is highly associated with the collateral circulation. And the competing endogenous RNAs (ceRNAs) generated from different compensatory supply regions may also involve in the regulation of ischemic tissues prognosis. In this study, we found the apoptosis progress of ischemic neurons in posterior circulation-supplied regions (close to PCA, cortex2) was much slower than that in anterior circulation-supplied territory (close to ACA, cortex1) in MCAO-3-h mice. Using the RNA sequencing and functional enrichment analysis, we analyzed the difference between RNA expression profile in cortex1 and cortex2 and the related biological processes. The results indicated that the differential expressed ceRNAs in cortex1 were involved in cell process under acute injury, while the differential expressed ceRNAs in cortex2 was more likely to participate in long-term injury and repair process. Besides, by establishing the miRNA-ceRNA interaction network we further sorted out two specifically distributed miRNAs, namely mmu-miR446i-3p (in cortex1) and mmu-miR3473d (in cortex2). And the specifically increased mmu-miR3473d in cortex2 mainly involved the angiogenesis and cell proliferation after ischemic stroke, which may be the critical reason for the longer therapeutic time window in cortex2. In conclusion, the present study reported the specific changes of ceRNAs in distinct compensatory regions potentially involved in the evolution of cerebral ischemic tissues and the unbalance prognosis after stroke. It provided more evidence for the collateral compensatory effects on patients' prognosis and carried out the new targets for the ischemic stroke therapy.

Chronic oral exposure to short chain chlorinated paraffins induced testicular toxicity by promoting NRF2-mediated oxidative stress

As a widespread environmental contaminant, short chain chlorinated paraffins (SCCPs) has attracted great attention. However, the toxicity of SCCPs on male reproductive system remains ambiguous. In this study, we treated mice with SCCPs by gavage and investigated the toxic effects of SCCPs on testis. According to the results, the sperm parameters of mice were significantly reduced after exposure to 1, 10, 100 mg/kg body mass per day SCCPs for 35 days. SCCPs resulted in disorderly arranged seminiferous epithelium and increased apoptotic cells in testes. Both in vivo and in vitro experiments indicated that the oxidative stress was induced after SCCPs exposure, and dysfunction of nuclear factor erythroid-related factor (NRF2) signaling pathway played a role in this process. Moreover, resveratrol, an NRF2 activator, could alleviate the damage of SCCPs onmale reproductive system. Our study indicated that oxidative stress is the key point for explaining the testicular toxicity caused by SCCPs, and NRF2 could be used as a potential target for clinical treatment to alleviate the reproductive toxicity induced by SCCPs.

Inhibition of A1 Astrocytes and Activation of A2 Astrocytes for the Treatment of Spinal Cord Injury

Spinal cord injury (SCI) is a serious injury to the central nervous system that causes significant physical and psychological trauma to the patient. SCI includes primary spinal cord injuries and secondary spinal cord injuries. The secondary injury refers to the pathological process or reaction after the primary injury. Although SCI has always been thought to be an incurable injury, the human nerve has the ability to repair itself after an injury. However, the reparability is limited because glial scar formation impedes functional recovery. There is a type of astrocyte that can differentiate into two forms of reactive astrocytes known as 'A1' and 'A2' astrocytes. A1 astrocytes release cytotoxic chemicals that cause neurons and oligodendrocytes to die and perform a harmful role. A2 astrocytes can produce neurotrophic factors and act as neuroprotectors. This article discusses ways to block A1 astrocytes while stimulating A2 astrocytes to formulate a new treatment for spinal cord injury.

The opposite effect of convulsant drugs on neuronal and endothelial nitric oxide synthase - A possible explanation for the dual proconvulsive/anticonvulsive action of nitric oxide

Nitric oxide (NO) participates in processes such as endothelium-dependent vasodilation and neurotransmission/neuromodulation. The role of NO in epilepsy is controversial, attributing it to anticonvulsant but also proconvulsant properties. Clarification of this dual effect of NO might lead to the development of new antiepileptic drugs. Previous results in our laboratory indicated that this contradictory role of NO in seizures could depend on the nitric oxide synthase (NOS) isoform involved, which could play opposite roles in epileptogenesis, one of them being proconvulsant but the other anticonvulsant. The effect of convulsant drugs on neuronal NO (nNO) and endothelial NO (eNO) levels was investigated. Considering the distribution of neuronal and endothelial NOS in neurons and astrocytes, resp., primary cultures of neurons and astrocytes were used as a study model. The effects of convulsant drugs pentylenetetrazole, thiosemicarbazide, 4-aminopyridine and bicuculline on NO levels were studied, using a spectrophotometric method. Their effects on NO levels in neurons and astrocytes depend on the concentration and time of treatment. These convulsant drugs caused an increase in nNO, but a decrease in eNO was proportional to the duration of treatment in both cases. Apparently, nNO possesses convulsant properties mediated by its effect on the glutamatergic and GABAergic systems, probably through GABA_A receptors. Anticonvulsant properties of eNO may be the consequence of its effect on endothelial vasodilation and its capability to induce angiogenesis. Described effects last as seizures do. Considering the limitations of these kinds of studies and the unexplored influence of inducible NO, further investigations are required.

Human umbilical cord mesenchymal stem cells-derived exosomal circDLGAP4 promotes angiogenesis after cerebral ischemia-reperfusion injury by regulating miR-320/KLF5 axis

Accumulating evidence suggests that human umbilical cord mesenchymal stem cell-derived exosomes (hUC-MSCs-Exos) are a promising therapeutic strategy for cerebral ischemia-reperfusion injury (CIRI). However, the underlying mechanism remains unclear. hUC-MSCs-Exos were identified by electron microscopy, NTA, and Western blotting. In the hypoxia/reoxygenation (H/R) cell model, human brain microvascular endothelial cells (HBMECs) were cocultured with hUC-MSCs-Exos. Then, cell viability, migration, apoptosis, and tube formation were measured by MTT, flow cytometry, transwell, and tube formation assays. RT-qPCR and Western blotting were used to detect the changes in RNA and protein. RNA pull-down and dual luciferase reporter assays confirmed the relationship between circDLGAP4, miR-320, and KLF5. Ischemia-reperfusion (I/R) rat model was established for in vivo experiments. hUC-MSCs-Exos increased the expression levels of circDLGAP4 and KLF5 but decreased miR-320 in H/R-treated HBMECs by transferring exosomal circDLGAP4. Knockdown of circDLGAP4 in hUC-MSCs-Exos reversed the promoting effects of hUC-MSCs-Exos on cell viability, migration, and tube formation in H/R-treated HBMECs in vitro and also abolished the protective effects of hUC-MSCs-Exos on cerebrovascular injury in I/R rats. Mechanistically, exosomal circDLGAP4 negatively regulated miR-320 in HBMECs, which directly bound to KLF5. In addition, the downregulation of miR-320 could reverse the regulatory effect of exosomal shcircDLGAL5 in H/R-treated HBMECs by upregulating KLF5. hUC-MSCs-Exos-derived circDLGAP4 reduced cerebrovascular injury by regulating miR-320/KLF5 signaling. These results provide a stem cell-based approach to treat CIRI.

Lipoprotein(a) and Atherosclerotic Cardiovascular Diseases: Evidence from Chinese Population

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Multiple factors are involved in CVD, and emerging data indicate that lipoprotein(a) (Lp(a)) may be associated with atherosclerotic cardiovascular disease (ASCVD) independent of other traditional risk factors. Lp(a) has been identified as a novel therapeutic target. Previous studies on the influence of Lp(a) in CVD have mainly used in western populations. In this review, the association of plasma Lp(a) concentration with ASCVD was summarized, with regards to epidemiological, population-based observational, and pathological studies in Chinese populations. Lp(a) mutations and copy number variations in Chinese populations are also explored. Finally, the impact of plasma Lp(a) levels on patients with type 2 diabetes mellitus, cancer, and familial hypercholesterolemia are discussed.

miR‑222-3p reduces neuronal cell apoptosis and alleviates spinal cord injury by inhibiting Bbc3 and Bim

Spinal cord injury (SCI) is a severe traumatic event, but without any established effective treatment because of the irreversible neuronal death. Here, we investigated the role of miR-222-3p in neuronal apoptosis following SCI. Rat SCI models and neuron hypoxia models were accordingly established. The Bbc3, Bim, Bcl-2, Bax, cleaved-caspase 3, cleaved-caspase 9, Cytochrome c, and miR-222-3p expression levels were examined by Western blotting and real-time reverse transcription polymerase chain reaction (RT-qPCR). The possible association between miR-222-3p and Bbc3/Bim was analyzed by dual-luciferase assay. The neuron viability was assessed by Cell Counting Kit-8 assay and Nissl's staining. Live cell staining was performed to detect the mitochondrial membrane potential and neuronal apoptosis. Rat locomotor function was assessed using the Basso-Beattie-Bresnahan scores. Cytochrome c was outflowed from the mitochondria after SCI or hypoxia treatment, and Bbc3, Bim, Bax, cleaved-caspase 9, and cleaved-caspase 3 were significantly upregulated, while Bcl-2 and miR-222-3p were decreased remarkably. Meanwhile, neuronal cell viability was significantly inhibited. Treatment of miR-222-3p significantly suppressed the Cytochrome c efflux and neuronal apoptosis and improved neuronal cell viability and motor function in SCI rats. Moreover, we found that Bbc3 and Bim were the direct targets of miR-222-3p. Overall, our data suggest that miR-222-3p could alleviate the mitochondrial pathway-mediated apoptosis and motor dysfunction in rats after SCI by targeting Bbc3 and Bim.