Brain Regional and Temporal Changes in BDNF mRNA and microRNA-206 Expression in Mice Exposed to Repeated Cycles of Chronic Intermittent Ethanol and Forced Swim Stress

Role of Lactobacillus plantarum-Derived Extracellular Vesicles in Regulating Alcohol Consumption

Alcohol Use Disorder (AUD), characterized by repeated alcohol consumption and withdrawal symptoms, poses a significant public health issue. Alcohol-induced impairment of the intestinal barrier results in alterations in intestinal permeability and the composition of the intestinal microbiota. Such alterations lead to a reduced relative abundance of intestinal lactic acid bacteria. However, the role of gut microbiota in alcohol consumption is not yet fully understood. In this study, we explore the mechanism by which gut microbiota regulates alcohol consumption, specifically using extracellular vesicles derived from Lactobacillus plantarum (L-EVs). L-EVs were administered to Sprague-Dawley rats either through intraperitoneal injection or microinjection into the ventral tegmental area (VTA), resulting in a significant reduction in alcohol consumption 72 hours after withdrawal. The observed reduction was akin to the effect of an intra-VTA microinjection of Brain-Derived Neurotrophic Factor (BDNF). Intriguingly, the microinjection of K252a (a Trk B antagonist) into the VTA blocked the reducing effect of L-EVs on alcohol consumption. The intraperitoneal injection of L-EVs restored the diminished BDNF expression in the VTA of alcohol-dependent rats. Furthermore, L-EVs rescued the low BDNF expression in alcohol-incubated PC12 cells. In conclusion, our study demonstrates that L-EVs attenuated alcohol consumption by enhancing BDNF expression in alcohol-dependent rats, thus suggesting the significant therapeutic potential of L-EVs in preventing excessive alcohol consumption.

Evidence for the Contribution of the miR-206/BDNF Pathway in the Pathophysiology of Depression

Depression is a complex disorder with substantial impacts on individual health and has major public health implications. Depression results from complex interactions between genetic and environmental factors. Epigenetic mechanisms, including DNA methylation, microRNAs (miRNAs), and histone modifications, can produce heritable phenotypic changes without a change in DNA sequence and recently were proven to mediate lasting increases in the risk of depression following exposure to adverse life events. Of these, miRNAs are gaining attention for their role in the pathogenesis of many stress-associated mental disorders, including depression. One such miRNA is microRNA-206 (miR-206), which is a critical candidate for increasing the susceptibility to stress. Although miR-206 is thought to be a typical muscle-specific miRNA, it is expressed throughout the brain, particularly in the hippocampus and prefrontal cortex. Until now, only a few studies have been conducted on rodents to understand the role of miR-206 in stress-related abnormalities in neurogenesis. However, the precise underlying molecular mechanism of miR-206-mediated depression-like behaviors remains largely unknown. Here, we reviewed recent advances in the field of biomedical and clinical research on the role of miR-206 in the pathogenesis of depression from studies using different tissues and various experimental designs and described how abnormalities in miR-206 expression in these tissues can affect neuronal functions. Moreover, we focused on studies investigating the brain-derived neurotrophic factor (BDNF) as a functional target of miR-206, where miR-206 has been implicated in the pathogenesis of depression by suppressing the expression of the BDNF. In summary, these studies confirm the existence of a tight correlation between the pathogenesis of depression and the miR-206/BDNF pathway.

BDNF Modulation by microRNAs: An Update on the Experimental Evidence

MicroRNAs can interfere with protein function by suppressing their messenger RNA translation or the synthesis of its related factors. The function of brain-derived neurotrophic factor (BDNF) is essential to the proper formation and function of the nervous system and is seen to be regulated by many microRNAs. However, understanding how microRNAs influence BDNF actions within cells requires a wider comprehension of their integrative regulatory mechanisms. Aim: In this literature review, we have synthesized the evidence of microRNA regulation on BDNF in cells and tissues, and provided an analytical discussion about direct and indirect mechanisms that appeared to be involved in BDNF regulation by microRNAs. Methods: Searches were conducted on PubMed.gov using the terms "BDNF" AND "MicroRNA" and "brain-derived neurotrophic factor" AND "MicroRNA", updated on 1 September 2023. Papers without open access were requested from the authors. One hundred and seventy-one papers were included for review and discussion. Results and Discussion: The local regulation of BDNF by microRNAs involves a complex interaction between a series of microRNAs with target proteins that can either inhibit or enhance BDNF expression, at the core of cell metabolism. Therefore, understanding this homeostatic balance provides resources for the future development of vector-delivery-based therapies for the neuroprotective effects of BDNF.

Neuron enriched extracellular vesicles' MicroRNA expression profiles as a marker of early life alcohol consumption

Alcohol consumption may impact and shape brain development through perturbed biological pathways and impaired molecular functions. We investigated the relationship between alcohol consumption rates and neuron-enriched extracellular vesicles' (EVs') microRNA (miRNA) expression to better understand the impact of alcohol use on early life brain biology. Neuron-enriched EVs' miRNA expression was measured from plasma samples collected from young people using a commercially available microarray platform while alcohol consumption was measured using the Alcohol Use Disorders Identification Test. Linear regression and network analyses were used to identify significantly differentially expressed miRNAs and to characterize the implicated biological pathways, respectively. Compared to alcohol naïve controls, young people reporting high alcohol consumption exhibited significantly higher expression of three neuron-enriched EVs' miRNAs including miR-30a-5p, miR-194-5p, and miR-339-3p, although only miR-30a-5p and miR-194-5p survived multiple test correction. The miRNA-miRNA interaction network inferred by a network inference algorithm did not detect any differentially expressed miRNAs with a high cutoff on edge scores. However, when the cutoff of the algorithm was reduced, five miRNAs were identified as interacting with miR-194-5p and miR-30a-5p. These seven miRNAs were associated with 25 biological functions; miR-194-5p was the most highly connected node and was highly correlated with the other miRNAs in this cluster. Our observed association between neuron-enriched EVs' miRNAs and alcohol consumption concurs with results from experimental animal models of alcohol use and suggests that high rates of alcohol consumption during the adolescent/young adult years may impact brain functioning and development by modulating miRNA expression.

Neural circuits for the adaptive regulation of fear and extinction memory

The regulation of fear memories is critical for adaptive behaviors and dysregulation of these processes is implicated in trauma- and stress-related disorders. Treatments for these disorders include pharmacological interventions as well as exposure-based therapies, which rely upon extinction learning. Considerable attention has been directed toward elucidating the neural mechanisms underlying fear and extinction learning. In this review, we will discuss historic discoveries and emerging evidence on the neural mechanisms of the adaptive regulation of fear and extinction memories. We will focus on neural circuits regulating the acquisition and extinction of Pavlovian fear conditioning in rodent models, particularly the role of the medial prefrontal cortex and hippocampus in the contextual control of extinguished fear memories. We will also consider new work revealing an important role for the thalamic nucleus reuniens in the modulation of prefrontal-hippocampal interactions in extinction learning and memory. Finally, we will explore the effects of stress on this circuit and the clinical implications of these findings.

Oxytocin Reduces Sensitized Stress-Induced Alcohol Relapse in a Model of Posttraumatic Stress Disorder and Alcohol Use Disorder Comorbidity

BACKGROUND

There is high comorbidity of posttraumatic stress disorder (PTSD) and alcohol use disorder with few effective treatment options. Animal models of PTSD have shown increases in alcohol drinking, but effects of stress history on subsequent vulnerability to alcohol relapse have not been examined. Here we present a mouse model of PTSD involving chronic multimodal stress exposure that resulted in long-lasting sensitization to stress-induced alcohol relapse, and this sensitized stress response was blocked by oxytocin (OT) administration.

METHODS

Male and female mice trained to self-administer alcohol were exposed to predator odor (TMT) + yohimbine over 5 consecutive days or left undisturbed. After reestablishing stable alcohol responding/intake, mice were tested under extinction conditions, and then all mice were exposed to TMT or context cues previously associated with TMT before a reinstatement test session. Separate studies examined messenger RNA expression of Oxt and Oxtr in hypothalamus following chronic stress exposure. A final study examined the effects of systemic administration of OT on stress-induced alcohol relapse in mice with and without a history of chronic stress experience.

RESULTS

Chronic stress exposure produced long-lasting sensitization to subsequent stress-induced alcohol relapse that also generalized to stress-related context cues and transcriptional changes in hypothalamic OT system. OT injected before the reinstatement test session completely blocked the sensitized stress-induced alcohol relapse effect.

CONCLUSIONS

Collectively, these results provide support for the therapeutic potential of OT, along with highlighting the value of utilizing this model in evaluating other pharmacological interventions for treatment of PTSD/alcohol use disorder comorbidity.

Neuron Enriched Exosomal MicroRNA Expression Profiles as a Marker of Early Life Alcohol Consumption

Background

Alcohol consumption may impact and shape brain development through perturbed biological pathways and impaired molecular functions. We investigated the relationship between alcohol consumption rates and neuron-enriched exosomal microRNA (miRNA) expression to better understand the impact of alcohol use on early life brain biology.

Methods

Neuron-enriched exosomal miRNA expression was measured from plasma samples collected from young people using a commercially available microarray platform while alcohol consumption was measured using the Alcohol Use Disorders Identification Test. Linear regression and network analyses were used to identify significantly differentially expressed miRNAs and to characterize the implicated biological pathways, respectively.

Results

Compared to alcohol naïve controls, young people reporting high alcohol consumption exhibited significantly higher expression of four neuron-enriched exosomal miRNAs including miR-30a-5p, miR-194-5p, and miR-339-3p, although only miR-30a-5p and miR-194-5p survived multiple test correction. The miRNA-miRNA interaction network inferred by a network inference algorithm did not detect any differentially expressed miRNAs with a high cutoff on edge scores. However, when the cutoff of the algorithm was reduced, five miRNAs were identified as interacting with miR-194-5p and miR-30a-5p. These seven miRNAs were associated with 25 biological functions; miR-194-5p was the most highly connected node and was highly correlated with the other miRNAs in this cluster.

Conclusions

Our observed association between neuron-enriched exosomal miRNAs and alcohol consumption concurs with results from experimental animal models of alcohol use and suggests that high rates of alcohol consumption during the adolescent/young adult years may impact brain functioning and development by modulating miRNA expression.

Live or heat-killed probiotic administration reduces anxiety and central cytokine expression in BALB/c mice, but differentially alters brain neurotransmitter gene expression

While the potential for probiotic supplements to act as adjunctive treatments for mood disorders has been widely demonstrated, the precise mode of action remains unclear. To investigate the psychotropic effects of a multi-species probiotic supplement on emotional behaviour in male BALB/c mice, we explored the potential mechanisms of action relating to the temporal changes in the mRNA expression of brain cytokines, growth factors, central 5HT receptor and serotonin transporter (SERT) and GABA receptor in the context of probiotic induced behavioural changes. The effects of a heat-killed probiotic, independent of microbial metabolic processes were also evaluated on the same outcomes to understand whether the host response to the bacteria is more or less important than the contribution of the metabolic activity of the bacteria themselves. Results showed that probiotic supplementation reduced anxiety-like behaviours, increased time spent in the light area of the light-dark box, and decreased the expression of pro-inflammatory cytokines in the brain. Furthermore, probiotic administration elevated hippocampal BDNF and decreased GABA_B1β expression. Interestingly, the heat-killed probiotic and its membrane fraction had similar effects on emotional behaviours and gene expression in the brain. The ingestion of live and heat-killed probiotic preparations also reduced TLR2 expression in the gut. Thus, the present study reveals that the anxiolytic action of a multispecies probiotic in BALB/c mice is independent of bacterial viability. This suggests that it is the host response to probiotics, rather than microbial metabolism that facilitates the molecular changes in the brain and downstream behaviours.

Cross-talk between the HPA axis and addiction-related regions in stressful situations

Addiction is a worldwide problem that has a negative impact on society by imposing significant costs on health care, public security, and the deactivation of the community economic cycle. Stress is an important risk factor in the development of addiction and relapse vulnerability. Here we review studies that have demonstrated the diverse roles of stress in addiction. Term searches were conducted manually in important reference journals as well as in the Google Scholar and PubMed databases, between 2010 and 2022. In each section of this narrative review, an effort has been made to use pertinent sources. First, we will provide an overview of changes in the Hypothalamus-Pituitary-Adrenal (HPA) axis component following stress, which impact reward-related regions including the ventral tegmental area (VTA) and nucleus accumbens (NAc). Then we will focus on internal factors altered by stress and their effects on drug addiction vulnerability. We conclude that alterations in neuro-inflammatory, neurotrophic, and neurotransmitter factors following stress pathways can impact related mechanisms on craving and relapse susceptibility.

Functional roles, regulatory mechanisms and theranostics applications of ncRNAs in alcohol use disorder

Alcohol use disorder (AUD) is one of the most prevalent neuropsychological disorders worldwide, and its pathogenesis is convoluted and poorly understood. There is considerable evidence demonstrating significant associations between multiple heritable factors and the onset and progression of AUD. In recent years, a substantial body of research conducted by emerging biotechnologies has increasingly highlighted the crucial roles of noncoding RNAs (ncRNAs) in the pathophysiology of mental diseases. As in-depth understanding of ncRNAs and their mechanisms of action, they have emerged as prospective diagnostic indicators and preclinical therapeutic targets for a variety of psychiatric illness, including AUD. Of note, dysregulated expression of ncRNAs such as circRNAs, lncRNAs and miRNAs was routinely found in AUD individuals, and besides, exogenous regulation of partial ncRNAs has also been shown to be effective in ameliorating alcohol preference and excessive alcohol consumption. However, the exact molecular mechanism still remains elusive. Herein, we systematically summarized current knowledge regarding alterations in the expression of certain ncRNAs as well as their-mediated regulatory mechanisms in individuals with AUD. And finally, we detailedly reviewed the potential theranostics applications of gene therapy agents targeting ncRNAs in AUD mice. Overall, a deeper comprehension of functional roles and biological mechanisms of ncRNAs may make significant contributions to the accurate diagnosis and effective treatment of AUD.

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

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

The Regulation of miR-206 on BDNF: A Motor Function Restoration Mechanism Research on Cerebral Ischemia Rats by Meridian Massage

As a frequent disease affecting the nervous system, cerebral infarction has emerged as a major cause of disability and elicits disorders in motor, sensation, and cognition as sequelae. No clear mechanism has been known in meridian massage despite it having been proved to be an effective therapeutic option. The study was carried out to explore the treatment of meridian massage on cerebral ischemia in rats and its effects on motor function restoration and nerve cell’s ultrastructure in the ischemic territory. The alleviated nerve damages and recovered injured brain tissues were found in the cerebral infarction model of SD rats after meridian massage. Expressions of miR-206 and the brain-derived neurotrophic factor (BDNF) in the gastrocnemius muscle were all well observed. The effects of miR-206 on BDNF were testified by overexpressed and interfered miR-206 in the C2C12 myoblast. Moreover, at the molecular level, meridian massage downregulated miR-206 expression at an elevated level of BDNF. Consequently, meridian massage exerts a vital role in promoting cerebral ischemia restoration, which is expected to provide an addition to the application of traditional Chinese medicine (TCM) in the reconstruction and treatment of cerebral ischemia.

Regulation of alcohol drinking by ventral striatum and extended amygdala circuitry

Alcohol use disorder is a complex psychiatric disorder that can be modeled in rodents using a number of drinking paradigms. Drinking-in-the-dark (DID) is widely used to model the binge/intoxication stage of addiction, and chronic intermittent ethanol vapor procedures (CIE) are used to induce dependence and model withdrawal/negative affect induced escalation of drinking. We discuss experiments showing the ventral striatum (vStr) and extended amygdala (EA) are engaged in response to ethanol in rodents through c-Fos/Fos immunoreactivity studies. We also discuss experiments in rodents that span a wide variety of techniques where the function of vStr and EA structures are changed following DID or CIE, and the role of neurotransmitter and neuropeptide systems studies in these ethanol-related outcomes. We note where signaling systems converge across regions and paradigms and where there are still gaps in the literature. Dynorphin/κ-opioid receptor (KOR) signaling, as well as corticotropin releasing factor (CRF)/CRF receptor signaling were found to be important regulators of drinking behaviors across brain regions and drinking paradigms. Future research will require that females and a variety of rodent strains are used in preclinical experiments in order to strengthen the generalizability of findings and improve the likelihood of success for testing potential therapeutics in human laboratory studies.

Rewarding and Antidepressant Properties of Ketamine and Ethanol: Effects on the Brain-Derived Neurotrophic Factor and TrkB and p75NTR Receptors

There is a high level of comorbidity between depression and alcohol use disorder. Subanesthetic doses of ketamine induce short-acting and enduring antidepressant effects after a single or a few administrations. Considering such comorbidity, we assessed, in Swiss male mice, if ketamine-induced antidepressant-like effects would alter ethanol's rewarding effects; and, if ethanol pretreatment would alter the rewarding and antidepressant effects of ketamine. The role of the brain-derived neurotrophic factor (BDNF) and its high and low affinity receptors TrkB and p75NTR, respectively, in both reward and depression-related behaviors is well established. The present study assessed, in outbred Swiss male mice, the expression of these proteins in the prefrontal cortex and hippocampus. Ketamine did not alter the development of ethanol-induced conditioned place preference (CPP), yet ethanol inhibited the expression of CPP induced by 50 mg/kg ketamine. The antidepressant action of 50 mg/kg ketamine was attenuated after repeated treatment (i.e., developed tolerance), an effect blocked by ethanol preexposure; ethanol also inhibited the antidepressant effect of 30 mg/kg ketamine. Ketamine (50 mg/kg) and Ethanol-Ketamine (50 mg/kg) groups showed lower levels of 145 kDa TrkB in the hippocampus than Saline-treated group. Ethanol-Ketamine (50 mg/kg) decreased the hippocampal expression of p75NTR compared to Saline-Saline and Saline-Ethanol groups. Ketamine (50 mg/kg) induced hippocampal downregulation of 145 kDa TrkB may contribute to ketamine-induced antidepressant tolerance. Likewise, a relationship between low hippocampal levels of p75NTR in the Ethanol-Ketamine (50 mg/kg) and ketamine-induced CPP blockade may be considered. The findings underscore potential ethanol-ketamine interactions likely to undermine ketamine putative antidepressant effects.

Dynorphin/Kappa Opioid Receptor Activity Within the Extended Amygdala Contributes to Stress-Enhanced Alcohol Drinking in Mice

BACKGROUND

While there is high comorbidity of stress-related disorders and alcohol use disorder, few effective treatments are available and elucidating underlying neurobiological mechanisms has been hampered by a general lack of reliable animal models. Here, we use a novel mouse model demonstrating robust and reproducible stress-enhanced alcohol drinking to examine the role of dynorphin/kappa opioid receptor (DYN/KOR) activity within the extended amygdala in mediating this stress-alcohol interaction.

METHODS

Mice received repeated weekly cycles of chronic intermittent ethanol exposure alternating with weekly drinking sessions ± forced swim stress exposure. Pdyn messenger RNA expression was measured in the central amygdala (CeA), and DYN-expressing CeA neurons were then targeted for chemogenetic inhibition. Finally, a KOR antagonist was microinjected into the CeA or bed nucleus of the stria terminalis to examine the role of KOR signaling in promoting stress-enhanced drinking.

RESULTS

Stress (forced swim stress) selectively increased alcohol drinking in mice with a history of chronic intermittent ethanol exposure, and this was accompanied by elevated Pdyn messenger RNA levels in the CeA. Targeted chemogenetic silencing of DYN-expressing CeA neurons blocked stress-enhanced drinking, and KOR antagonism in the CeA or bed nucleus of the stria terminalis significantly reduced stress-induced elevated alcohol consumption without altering moderate intake in control mice.

CONCLUSIONS

Using a novel and robust model of stress-enhanced alcohol drinking, a significant role for DYN/KOR activity within extended amygdala circuitry in mediating this effect was demonstrated, thereby providing further evidence that the DYN/KOR system may be a valuable target in the development of more effective treatments for individuals presenting with comorbidity of stress-related disorders and alcohol use disorder.

Growth Factors and Alcohol Use Disorder

Neurotrophic growth factors were originally characterized for their support in neuronal differentiation, outgrowth, and survival during development. However, it has been acknowledged that they also play a vital role in the adult brain. Abnormalities in growth factors have been implicated in a variety of neurological and psychiatric disorders, including alcohol use disorder (AUD). This work focuses on the interaction between alcohol and growth factors. We review literature suggesting that several growth factors play a unique role in the regulation of alcohol consumption, and that breakdown in these growth factor systems is linked to the development of AUD. Specifically, we focus on the brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), and insulin growth factor 1 (IGF-1). We also review the literature on the potential role of midkine (MDK) and pleiotrophin (PTN) and their receptor, anaplastic lymphoma kinase (ALK), in AUD. We show that alcohol alters the expression of these growth factors or their receptors in brain regions previously implicated in addiction, and that manipulations on these growth factors and their downstream signaling can affect alcohol-drinking behaviors in animal models. We conclude that there is a need for translational and clinical research to assess the therapeutic potential of new pharmacotherapies targeting these systems.

Differential expression of microRNAs in the hippocampi of male and female rodents after chronic alcohol administration

Background

Women are more vulnerable than men to the neurotoxicity and severe brain damage caused by chronic heavy alcohol use. In addition, brain damage due to chronic heavy alcohol use may be associated with sex-dependent epigenetic modifications. This study aimed to identify microRNAs (miRNAs) and their target genes that are differentially expressed in the hippocampi of male and female animal models in response to alcohol.

Methods

After chronic alcohol administration (3~3.5 g/kg/day) in male (control, n = 10; alcohol, n = 12) or female (control, n = 10; alcohol, n = 12) Sprague-Dawley rats for 6 weeks, we measured body weights and doublecortin (DCX; a neurogenesis marker) concentrations and analyzed up- or downregulated miRNAs using GeneChip miRNA 4.0 arrays. The differentially expressed miRNAs and their putative target genes were validated by RT-qPCR.

Results

Alcohol attenuated body weight gain only in the male group. On the other hand, alcohol led to increased serum AST in female rats and decreased serum total cholesterol concentrations in male rats. The expression of DCX was significantly reduced in the hippocampi of male alcohol-treated rats. Nine miRNAs were significantly up- or downregulated in male alcohol-treated rats, including upregulation of miR-125a-3p, let-7a-5p, and miR-3541, and downregulation of their target genes (Prdm5, Suv39h1, Ptprz1, Mapk9, Ing4, Wt1, Nkx3-1, Dab2ip, Rnf152, Ripk1, Lin28a, Apbb3, Nras, and Acvr1c). On the other hand, 7 miRNAs were significantly up- or downregulated in alcohol-treated female rats, including downregulation of miR-881-3p and miR-504 and upregulation of their target genes (Naa50, Clock, Cbfb, Arih1, Ube2g1, and Gng7).

Conclusions

These results suggest that chronic heavy alcohol use produces sex-dependent effects on neurogenesis and miRNA expression in the hippocampus and that sex differences should be considered when developing miRNA biomarkers to diagnose or treat alcoholics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-020-00342-3.

LncRNA KCNQ1OT1 Sponges miR-206 to Ameliorate Neural Injury Induced by Anesthesia via Up-Regulating BDNF

OBJECTIVE

Widely used in anesthesia, ketamine is reported to induce neurotoxicity in patients. This study aimed to investigate the molecular regulatory mechanism of long non-coding RNA (lncRNA) KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in ameliorating ketamine-induced neural injury.

MATERIALS AND METHODS

Sprague-Dawley rats were intraperitoneally injected with ketamine to induce neuronal injury. PC-12 cells treated with ketamine were used as the cell model. Ketamine-induced aberrant expression of KCNQ1OT1, miR-206 and brain-derived neurotrophic factor (BDNF) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). The effects of KCNQ1OT1 and miR-206 on ketamine-induced neural injury in PC-12 cells were then examined by MTT and LDH assay. The regulatory relationships between KCNQ1OT1 and miR-206, and miR-206 and BDNF were detected by dual-luciferase reporter assay.

RESULTS

Ketamine induced the apoptosis of neurons of the hippocampus in rats, and the apoptosis of PC-12 cells, accompanied by down-regulation of KCNQ1OT1 and BDNF expressions, and up-regulation of miR-206 expression. Overexpression of KCNQ1OT1 enhanced the resistance to apoptosis of PC-12 cells and significantly ameliorated ketamine-induced nerve injury, while transfection of miR-206 had opposite effects. Mechanistically, KCNQ1OT1 could target miR-206 and reduce its expression level, in turn indirectly increase the expression level of BDNF, and play a protective role in neural injury.

CONCLUSION

KCNQ1OT1/miR-206/BDNF axis is demonstrated to be an important regulatory mechanism in regulating ketamine-induced neural injury. Our study helps to clarify the mechanism by which ketamine exerts its toxicological effects and provides clues for the neuroprotection during anesthesia.