Cognitive dysfunction in schizophrenia patients caused by downregulation of γ-aminobutyric acid receptor subunits

BACKGROUND The expression pattern of gamma aminobutyric acid(GABA)receptor subunits are commonly altered in patients with schizophrenia,which may lead to nerve excitation/inhibition problems,affecting cognition,emotion,and behavior.AIM To explore GABA receptor expression and its relationship with schizophrenia and to provide insights into more effective treatments.METHODS This case-control study enrolled 126 patients with schizophrenia treated at our hospital and 126 healthy volunteers who underwent physical examinations at our hospital during the same period.The expression levels of the GABA receptor subunits were detected using 1H-magnetic resonance spectroscopy.The recognized cognitive battery tool,the MATRICS Consensus Cognitive Battery,was used to evaluate the scores for various dimensions of cognitive function.The correlation between GABA receptor subunit downregulation and schizophrenia was also analyzed.RESULTS Significant differences in GABA receptor subunit levels were found between the case and control groups(P<0.05).A significant difference was also found between the case and control groups in terms of cognitive function measures,including attention/alertness and learning ability(P<0.05).Specifically,as the expression levels of GABRA1(α1 subunit gene),GABRB2(β2 subunit gene),GABRD(δsubunit),and GABRE(εsubunit)decreased,the severity of the patients’condition increased gradually,indicating a positive correlation between the downregulation of these 4 receptor subunits and schizophrenia(P<0.05).However,the expression levels of GABRA5(α5 subunit gene)and GABRA6(α6 subunit gene)showed no significant correlation with schizophrenia(P>0.05).CONCLUSION Downregulation of the GABA receptor subunits is positively correlated with schizophrenia.In other words,when GABA receptor subunits are downregulated in patients,cognitive impairment becomes more severe.

Cardioprotective Potential of Cymbopogon citratus Essential Oil against Isoproterenol-induced Cardiomyocyte Hypertrophy:Possible Involvement of NLRP3 Inflammasome and Oxidative Phosphorylation Complex Subunits

Objective:Cymbopogon citratus(DC.)Stapf is a medicinal and edible herb that is widely used for the treatment of gastric,nervous and hypertensive disorders.In this study,we investigated the cardioprotective effects and mechanisms of the essential oil,the main active ingredient of Cymbopogon citratus,on isoproterenol(ISO)-induced cardiomyocyte hypertrophy.Methods:The compositions of Cymbopogon citratus essential oil(CCEO)were determined by gas chromatography-mass spectrometry.Cardiomyocytes were pretreated with 16.9µg/L CCEO for 1 h followed by 10µmol/L ISO for 24 h.Cardiac hypertrophy-related indicators and NLRP3 inflammasome expression were evaluated.Subsequently,transcriptome sequencing(RNA-seq)and target verification were used to further explore the underlying mechanism.Results:Our results showed that the CCEO mainly included citronellal(45.66%),geraniol(23.32%),and citronellol(10.37%).CCEO inhibited ISO-induced increases in cell surface area and protein content,as well as the upregulation of fetal gene expression.Moreover,CCEO inhibited ISO-induced NLRP3 inflammasome expression,as evidenced by decreased lactate dehydrogenase content and downregulated mRNA levels of NLRP3,ASC,CASP1,GSDMD,and IL-1β,as well as reduced protein levels of NLRP3,ASC,pro-caspase-1,caspase-1(p20),GSDMD-FL,GSDMD-N,and pro-IL-1β.The RNA-seq results showed that CCEO inhibited the increase in the mRNA levels of 26 oxidative phosphorylation complex subunits in ISO-treated cardiomyocytes.Our further experiments confirmed that CCEO suppressed ISO-induced upregulation of mt-Nd1,Sdhd,mt-Cytb,Uqcrq,and mt-Atp6 but had no obvious effects on mt-Col expression.Conclusion:CCEO inhibits ISO-induced cardiomyocyte hypertrophy through the suppression of NLRP3 inflammasome expression and the regulation of several oxidative phosphorylation complex subunits.

Effects of Nourishing “Yin”-Removing “Fire” Chinese Herb Mixture on the Differential Expression of GABA_AReceptor <i>α</i>Subunits in Hypothalamus of Precocious Puberty Female Rats

GABAergic input to Gonadotropin-releasing hormone (GnRH) neurons is necessary to initiate the onset of puberty and its action mainly depends on GABAA receptor of which the subunit composition, properties and consequently function varies during this period. Nourishing “Yin”-Removing “Fire” Chinese herb mixture, a Chinese herb-based formulation, has been proved that it may retard the initiation of pubertal development in female precocious puberty rats. Our objective is to investigate the effects of Nourishing “Yin”-Removing “Fire” Chinese herb mixture on the expression of GABAA receptor α subunits in hypothalamus. Female Sprague-Dawley rats were divided into normal (N), precocious puberty model (M) induced by danazol, model exposed to saline (MS) and model exposed to Chinese herb mixture (CHM) groups. All rats were administered by the Chinese herb mixture from P15 on. Coefficients of reproductive organs and serum gonadotropins and estradiol levels in M were significantly enhanced while they were significantly decreased in CHM. The hypothalamic GnRH mRNA was also significantly increased in M and in CHM, as well as ERα mRNA. At the mean time, the hypothalamic GABAA receptor α1 and α3 subunits mRNA were more significantly decreased in M than those of N, while they were more significantly enhanced in CHM than those in M (p 0.01), the protein expression of which in hypothalamus had the same trend as the mRNA expression. The evidence suggests that Nourishing “Yin”-Removing “Fire” Chinese herb mixture could significantly retard the sexual development of the precocious rats, and up-regulate the expressions of hypothalamic GABAA receptor α1 and α3 subunits. Our result indicated that GABAA receptor α1 and α3 subunits might involve in the effective treatment of herb mixture on idiopathic precocious puberty.

Attenuation of nicotine-evoked Ca²⁺influx by antibody to the nicotinic acetylcholine receptor <i>α</i>3 subunits in human embryonic kidney cells

Autoantibody against neuronal nicotinic acetylcholine receptor (nAChR) α3 subunit is implicated in severe autonomic dysfunction in the patients with autoimmune autonomic ganglionopathy (AAG). Although this autoantibody has been revealed to impair fast excitatory synaptic transmission in autonomic ganglia, its precise mechanism remains unknown. Here, we show that antibody-induced reduction of cell-surface α3 subunits result in impairment of nicotine-evoked Ca2+ influx in stably transfected human embryonic kidney cells. These effects of the antibody were remarkably inhibited by interfering with the endocytic machinery at low-temperature. We conclude that reduction of nAChR in autonomic ganglia can be mediated by the endocytosis of α3 subunits, and resulted in autonomic failure in AAG patients.

Neuroprotective effects of autophagy inhibition on hippocampal glutamate receptor subunits after hypoxia-ischemia-induced brain damage in newborn rats

Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage（HIBD）.However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine（10 m M in 10 μL） or the autophagy stimulator rapamycin（1 g/kg） 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.

Role of brahma-related gene 1/brahma-associated factor subunits in neural stem/progenitor cells and related neural developmental disorders

Different fates of neural stem/progenitor cells(NSPCs)and their progeny are determined by the gene regulatory network,where a chromatin-remodeling complex affects synergy with other regulators.Here,we review recent research progress indicating that the BRG1/BRM-associated factor(BAF)complex plays an important role in NSPCs during neural development and neural developmental disorders.Several studies based on animal models have shown that mutations in the BAF complex may cause abnormal neural differentiation,which can also lead to various diseases in humans.We discussed BAF complex subunits and their main characteristics in NSPCs.With advances in studies of human pluripotent stem cells and the feasibility of driving their differentiation into NSPCs,we can now investigate the role of the BAF complex in regulating the balance between self-renewal and differentiation of NSPCs.Considering recent progress in these research areas,we suggest that three approaches should be used in investigations in the near future.Sequencing of whole human exome and genome-wide association studies suggest that mutations in the subunits of the BAF complex are related to neurodevelopmental disorders.More insight into the mechanism of BAF complex regulation in NSPCs during neural cell fate decisions and neurodevelopment may help in exploiting new methods for clinical applications.

Allelic Variation and Genetic Diversity at HMW Glutenin Subunits Loci in Yunnan, Tibetan and Xinjiang Wheat

Allelic variation and genetic diversity at HMW glutenin subunits loci, Glu-A1, Glu-B1and Glu-D1 were investigated in 64 accessions of three unique wheats of western Chinausing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Two HMWglutenin patterns (i.e., null, 7+8, 2+12 and null, 7, 2+12) in 34 Yunnan wheataccessions, 3 HMW glutenin patterns (i.e., null, 7+8, 2+12; null, 6+8, 2+12 andnull, 7+8, 2) in 24 Tibetan accessions and 1 HMW glutenin pattern (null, 7, 2+12) in6 Xinjiang wheat accessions were found. The Tibetan accession TB18 was found to be witha rare subunit 2 encoded by Glu-D1. A total of 4 (i.e., Glu-A1c, Glu-B1a, Glu-B1b andGlu-D1a), 5 (i.e., Glu-A1c, Glu-B1d, Glu-B1b, Glu-D1a and Glu-D1) and 3 alleles (i.e.,Glu-A1c, Glu-B1a and Glu-D1a) at Glu-1 locus were identified among Yunnan, Tibetan andXinjiang unique wheat accessions, respectively. For Yunnan wheat, Tibetan wheat andXinjiang wheat, the Neis mean genetic variation indexes were 0.1574, 0.1366 and 0,respectively, which might indicate the higher genetic diversity at HMW glutenin subunitsloci of Yunnan and Tibetan wheat accessions as compared to that of Xinjiang wheataccessions. Among the three genomes of hexaploid wheats of western China, the highestNeis genetic variation index was appeared in B genome with the mean value of 0.2674,while the indexes for genomes A and D were 0 and 0.0270, respectively. It might bereasonable to indicate that Glu-B1 showed the highest, Glu-D1 the intermediate and Glu-A1 always the lowest genetic diversity.

Cloning and Functional Analysis of Calcineurin Subunits A and B in Development and Fecundity of Nilaparvata lugens(Stål)

Serine/threonine phosphatase calcineurin(CN)is a unique but confounding calcium/calmodulin-mediated enzyme,which is composed of a catalytic subunit A(CNA)and a regulatory subunit B(CNB).We cloned six transcripts for CNA named from NlCNA-X1 to NlCNA-X6,one CNB named NlCNB1 and one CNB homologous gene NlCNBH1 from Nilaparvata lugens.All of them are constitutively transcripted in various tissues and developmental stages.The primary structure of the six isoforms showed obvious differences in the length and composition of the amino acid sequence between the two binding domains of Ca^(2+)/calmodulin(CaM)and CNB.Ca^(2+)-binding EF-hand motifs were found in NlCNB1 and NlCNBH1.The specific gene silencing of NlCNA,NlCNB1 and NlCNBH1 respectively by RNAi resulted in drastical reduction in survival rate,female weight,eclosion rate and fecundity of N.lugens.These results showed that NlCNA,NlCNB1 and NlCNBH1 were required for N.lugens growth and reproduction.The negative effects of NlCNB1 silence on nymph mortality(97%),molting malformation(90%)and female sterile(50%)were more serious than those of NlCNA or NlCNBH1.qRT-PCR and enzyme-linked immunosorbent assay(ELISA)analyses indicated that the nymphs with silenced NlCNA,NlCNB1 or NlCNBH1 showed impaired hormone and energy metabolism.In nymphs,the contents of 20-hydroxyecdysone(20E)after NlCNB1 RNAi and phenoloxidase after NlCNA RNAi were particularly decreased.These results suggested that NlCNA is involved in immunity of N.lugens by regulation of phenoloxidase,while NlCNB1 may control the growth and development of N.lugens by 20E signaling pathway in addition to interact with CNA.Injection of 70 ng/μL dsNlCNB1 resulted in 77.0%down regulation of NlCNB1,and the nymph mortality was up to 57.9%at 10 d after injection.Therefore,NlCNB1 could be a potential candidate target used for strategy design in control of N.lugens.Our results revealed the importance of CN in the regulation of the growth and development of N.lugens,which provided a basis for further study of the molecular mechanism of CN.

Expression of mRNA-encoding subunits of N-methyl-D-aspartate receptor in the hypothalamus in sustained monaural block of auditory air-conduction model rats

A sustained monaural block of auditory air-conduction model was established in rats through subcutaneous suture in the right ear canal.The gene expression levels of hypothalamic N-methyl-D-aspartate receptor NR1,NR2A,NR2B and NR2C mRNA in the auditory central nervous system of Sprague-Dawley rats at postnatal 9,23,37 days were determined after an environmental change.Reverse transcription-PCR assay showed that the critical period for the development of NR1,NR2A,and NR2B subunits in the left hypothalamus and NR1-and NR2B-dependent auditory neurons in the right hypothalamus terminated 23 days after the suture in the right ear.The critical period for the development of NR2A subunit-dependent auditory neurons in the right hypothalamus was terminated by postnatal day 37.The results confirmed that N-methyl-D-aspartate receptor subunits in the hypothalamus may be regulated by the auditory environment.

Synthetic protease inhibitor-induced inclusions in PC12 cells Potential proteomic characterization of six subunits in the 26S proteasome

Proteasome dysfunction during dopaminergic degeneration induces proteolytic stress, and is a contributing factor for the onset and formation of Lewy bodies. Results from our previous studies showed that synthetic proteasome inhibitor-induced inclusions in PC12 cells contained six subunits in the 26S proteasome. In the present study, mass spectrometry analysis of single protein spots resolved by two-dimensional gel electrophoresis and identified by bioinformatic analysis of peptide mass fingerprint （PMF） data were performed to comprehensively characterize the proteomic profile of the proteasome subunits. Results showed that six subunits in the 26S proteasome were characterized through accurate assignment by PMF data-specific protein identification in protein databases. Additionally, identification of one of the proteasome subunits was further confirmed using a subunit-specific antibody against non-adenosine triphosphatase subunit 11 of the 19S regulatory particle. Results suggest that the potential proteomic profile of six subunits in the 26S proteasome could be established from proteasome inhibitor-induced inclusions in PC12 cells.

Analysis of Dynamic Accumulation of Three Types of Glutenin Subunits and Their Content in Relation to Sedimentation Value in Common Wheat

The biosynthetic time and accumulations of A-, B-, and C-type glutenin subunits in 7 winter wheat cultivars with different quality （strong, medium, weak gluten） were analyzed by SDS-PAGE. The results showed that no glutenin subunit was observed within 8 d after anthesis. Parts or all A-, B-, and C-type subunits appeared around day 12 in different cultivars. Other A-, B-, and C-type subunits appeared gradually. The accumulation of A-, B-, and C-type subunits fluctuated before maturity. The results of analysis of correlation between the ratios of A/T （total content of glutenin subunits）, A/C, AJ （B＋C）, （A＋B）/C, and （A＋B）/T and SDS-sedimentation value suggested that they were more significant. The negative correlation between the ratio of （B＋C）/T and SDS-sedimentation value was more significant, and the correlations between the ratio C/T and the SDS-sedimentation value were significantly negative.

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals.The comorbidity of the two neurological disorders represents a grave health threat to older populations.This review presents a brief background of the development of novel concepts and their clinical potentials.The activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal function.An ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic site.This Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute excitotoxicity.Furthermore,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death pathways.Based on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic neuropathogenesis.The N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic excitotoxicity.Ischemic stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time courses.It is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related dementia.This early treatment simultaneously serves as a preconditioning therapy against ischemic stroke that often attacks the same individuals during abnormal aging.

Composition and Content of High-Molecular-Weight Glutenin Subunits and Their Effects on Wheat Quality

Sedimentation values, flour glutenin macropolymer (GMP) contents, composition and contents of high-molecular-weight (HMW) glutenin subunits (GS) of 233 flour samples were determined. Our data indicated that subunit 1 occurred more frequently at Glu-A1 , subunit pair 7 + 8 at Glu-B1 and 2 + 12 at Glu-D1. The significant relationships between Glu-1 quality score and total HMW glutenin content, sedimentation value and GMP content suggested that the composition of HMW-GS affects wheat quality strongly. Moreover, the total content of HMW-GS was correlated with certain quality parameters more significantly. Relationship between subunit 5 + 10 content and breadmaking quality was better than others, but 2 + 12, 7 + 8, 7 + 9 and 4 + 12 also correlated with certain quality parameters significantly. The contents of total HMW-glutenin, x-type subunits and y-type subunits related with sedimentation value, flour GMP content, and Glu-1 quality score more strongly than that of individual subunit or subunit pair. The flour GMP content, with excellent correlation to sedimentation value, total contents of HMW glutenin, x- and y-type subunits and many other quality parameters, could be an ideal indicator of breadmaking quality at earlier generations for breeding purpose for its simple procedure and small scale.

Characterization of High-Molecular-Weight Glutenin Subunits and Their Coding Genes from Aegilops umbellulata

The high-molecular-weight (HMW) glutenin subunits and their coding genes from Aegilops umbellulata Zhuk. (UU, 2n = 2x = 14) were characterized using SDS-PAGE analysis and molecular approaches. SDS-PAGE analysis showed that the 1Ux subunits from four different accessions possessed electrophoretic mobilities close to, or slower than, that displayed by the 1Dx2.2 subunit of common wheat. The electrophoretic mobilities of the 1Uy subunits were generally similar to those shown by the 1Dy subunits of common wheat. The complete open reading frames of the 1Ux and 1Uy genes were amplified by PCR and subsequently cloned and sequenced. Amino acid sequence comparisons suggested that the primary structure of the 1Ux and 1Uy subunits were identical to that of published HMW glutenin subunits from related species, Phylogenetic analysis indicated that the HMW glutenin subunits of Ae. umbellulata were most closely related to those encoded by the D genome of Triticeae.

Thylakoid Transit Peptide Is Related to the Expression and Localization of NdhB Subunits in Soybean

The chloroplast NAD(P)H dehydrogenase(NDH)complex,as one of the most important photosynthesis protein complexes in thylakoid membrane,is involved in photosystem I(PSI)cyclic electron transport(CEF).Under abiotic environmental stress,the photosynthetic apparatus is susceptible to the damage caused by the strong light illumination.However,the enhancement of NDHdependent CEF could facilitate the alleviation of the damage to the photosynthetic apparatus.The NdhB subunit encoded by chloroplast genome is one of most important subunits of NDH complex and consists of 510 amino acids.Here,according to cloning ndhB from Melrose(cultivated soybean),ACC547(wild salt-tolerant soybean),S113-6 and S111-9(hybrid descendant),based on the comparison and analysis of the sequences of NdhB subunits,we found that there is a novel thylakoid transit peptide of NdhB subunit in S111-9.In addition,crosslink immunoprecipitation,immunogold labeling and co-expression of GFP fusion protein indicated that the novel thylakoid transit peptide is favorable to the expression and localization of NdhB subunit in chloroplast.Therefore,we suggest that this novel thylakoid transit peptide plays the same role as chaperonin and contributes to facilitating the expression and localization of NdhB subunit.

Non-Thermal Radio Frequency Stimulation Inhibits the Tryptophan Synthase Beta Subunit in the Algae <i>Chlamydomonas reinhardtii</i>

To demonstrate the ability of the Nativis signal transduction technology (Butters et al. 2014) to modulate the expression of algae mRNA and protein, we tested if we can alter specific enzyme levels in Chlamydomonas reinhardtii. We inhibited the synthesis of the enzyme tryptophan synthase beta subunit (MAA7) by applying the signal derived from a published siRNA (Zhao et al. 2009). With lower levels of MAA7, Chlamydomonas reinhardtii can grow in the presence of the prodrug 5-Fluoroindole (5-FI), because less 5-Fluoroin-dole can be converted to the toxic 5-Fluoro-L-tryptophan (5-FT). We find a 24% (&plusmn;5%) increase of growth with the signal versus no signal. To see if that effect was due to the reduction of the amount of mRNA encoding MAA7, we used Real-Time Quantitative PCR (RT-QPCR) to measure the levels of MAA7 mRNA. To normalize the MAA7 mRNA level, we compared them to the levels of a mRNA that is not affected by the signal (G protein beta subunit-like polypeptide, Cblp). Two conditions increase the effectiveness of the signal. One can either treat the cell cultures during the logarithmic growth phase (starting the cultures at density of 0.104 OD at 750 nm). Or one can treat the cultures at a later stage of the logarithmic growth, but treating them for a longer time (8.7% versus 3.5% of the culture time). Under these conditions we found around a 50% decrease in the mRNA levels for MAA7. Treating the cultures at the earlier growth phase or at a later growth phase is less effective, with only a 20% effect.

A Simple LDT-PCR Method for Detection of Various Nucleic Acid Sequence Changes in a Small Region of Genes—Application for the Identification of Gene Mutations in MTB <i>rpoB</i>Gene Associated with Drug Resistance

A modified low denaturing temperature PCR (LDT-PCR) method combined with DNA microarray technique is developed in our lab for quick and effective identification of various mutations in an 81 base pair region of Mycobacterium Tuberculosis (MTB) ribosome RNA polymerase subunit B (rpoB) gene associated with rifampin resistance. By incurporation of wild type (wt) allele fragments that had been PCR amplified previously, the target PCR fragments coming from mutant clinical MTB samples were codenaturized with incorporated wt type allele fragment at 94°C and then let them randomly form matched structures (homoduplex) and allele mismatch-containing structures (heteroduplex), respectively, when the temperature cooled down to 70°C. After the temperature was raised to 80°C, the heteroduplex double stranded fragments were preferentially denatured and resulted in PCR amplification as well as fluorescence incurporation. Since the homoduplex fragments need a higher temperature to be denatured, they were kept in double-stranded status at that temperature and failed to be PCR amplified. By hybridization of LDT-PCR products with the probes spotted on microarray slides, the fluorescent signals representing the presence of gene mutations were detected. We have tested this method on 35 clinical MTB samples and obtained satisfied results.

MicroRNA-502-3p regulates GABAergic synapse function in hippocampal neurons

Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.

N-methyl-D-aspartate receptor subunit 1 regulates neurogenesis in the hippocampal dentate gyrus of schizophrenia-like mice

N-methyl-D-aspartate receptor hypofunction is the basis of pathophysiology in schizophrenia. Blocking the N-methyl-D-aspartate receptor impairs learning and memory abilities and induces pathological changes in the brain. Previous studies have paid little attention to the role of the N-methyl-D-aspartate receptor subunit 1 (NR1) in neurogenesis in the hippocampus of schizophrenia. A mouse model of schizophrenia was established by intraperitoneal injection of 0.6 mg/kg MK-801, once a day, for 14 days. In N-methyl-D-aspartate-treated mice, N-methyl-D-aspartate was administered by intracerebroventricular injection in schizophrenia mice on day 15. The number of NR1-, Ki67- or BrdU-immunoreactive cells in the dentate gyrus was measured by immunofluorescence staining. Our data showed the number of NR1-immunoreactive cells increased along with the decreasing numbers of BrdU- and Ki67-immunoreactive cells in the schizophrenia groups compared with the control group. N-methyl-D-aspartate could reverse the above changes. These results indicated that NR1 can regulate neurogenesis in the hippocampal dentate gyrus of schizophrenia mice, supporting NR1 as a promising therapeutic target in the treatment of schizophrenia. This study was approved by the Experimental Animal Ethics Committee of the Ningxia Medical University, China (approval No. 2014-014) on March 6, 2014.

Expression changes of activin A in the development of hepatic fibrosis

AIM: To examine the expression of activin A, a member of the transforming growth factor (TGFbeta) superfamily, recently has been reported to be overexpressed in liver cirrhosis, in the course of carbon tetrachloride-induced rat hepatic fibrosis. METHODS: Hepatic fibrosis was induced in rats by subcutaneous injections of 40% carbon tetrachloride oily solution for a period of 1 to 7 weeks. At the end of 1, 2, 3, 4, 5, 6 and 7 weeks after carbon tetrachloride injections, the rats were killed in group (6-10 rats each time) for study. The activin A messenger RNA expression and its protein localization were assessed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: The normal rat liver expressed activin A mRNA and protein, and its expression was transiently decreased and became undetectable after carbon tetrachloride injections for 2 or 3 weeks and then increased gradually. After injection of carbon tetrachloride for 6 and 7 weeks, activin A mRNA and protein expressions were significantly enhanced in rat liver. Compared with that of the normal rat liver. Activin A mRNA expression levels in rats receiving carbon tetrachloride injections for 6 and 7 weeks were 1.6 and 2.2 times that of those in normal rat liver respectively (0.456 +/- 0.094 vs 0.2860.0670, P【 0.01; 0.620 +/- 0.134 vs 0.286 +/- 0670, P【 0.01). Immunohistochemistry showed that activin A expressed in hepatocytes of normal liver, and its expression was decreased in rats receiving carbon tetrachloride for 2 or 3 weeks. Compared with normal liver, activin A expression distribution mode changed in fibrotic liver, being increased significantly in hepatocytes around fibrotic areas. CONCLUSION: Activin A expression was increased in late stage of hepatic fibrosis, and this may be involved in hepatic fibrosis formation in this period.