Forebrain excitatory neuron-specific loss of Brpf1 attenuates excitatory synaptic transmission and impairs spatial and fear memory

Bromodomain and plant homeodomain(PHD)finger containing protein 1(Brpf1)is an activator and scaffold protein of a multiunit complex that includes other components involving lysine acetyltransferase(KAT)6A/6B/7.Brpf1,KAT6A,and KAT6B mutations were identified as the causal genes of neurodevelopmental disorders leading to intellectual disability.Our previous work revealed strong and specific expression of Brpf1 in both the postnatal and adult forebrain,especially the hippocampus,which has essential roles in learning and memory.Here,we hypothesized that Brpf1 plays critical roles in the function of forebrain excitatory neurons,and that its deficiency leads to learning and memory deficits.To test this,we knocked out Brpf1 in forebrain excitatory neurons using CaMKIIa-Cre.We found that Brpf1 deficiency reduced the frequency of miniature excitatory postsynaptic currents and downregulated the expression of genes Pcdhgb1,Slc16a7,Robo3,and Rho,which are related to neural development,synapse function,and memory,thereby damaging spatial and fear memory in mice.These findings help explain the mechanisms of intellectual impairment in patients with BRPF1 mutation.

Synthesis and structure determination of pyrazine-containing macrocyclic polyazomethines

Two pyrazine-containing macrocyclic polyazomethines 2 and 3 were synthesized by direct [2 ＋ 2] and [3 ＋ 3] condensation reactions between 2,21-[pyrazine-2,3-diylbis（oxy）]dibenzaldehyde （1） and hydrazine. Both 2 and 3 were characterized by NMR, HRMS, and their structures were determined via X-ray crystal diffraction studies.

Mutated recombinant human glucagon-like peptide-1 induces differentiation of PC12 cells

Glucagon-like peptide-1 （GLP-1） and its long-acting analogues have neuroprotective and neurotrophic properties and are emerging as potential treatments for neurodegenerative diseases. Its short half-life has limited the application of GLP-1 in the clinic. We generated a mutated form of human GLP-1 （mGLP-1） using site-directed mutagenesis and gene recombination techniques, and found that these modifications significantly prolonged the biological half-life of GLP-1 compared with native GLP-1 （nGLP-1）. This study investigated the role of mGLP-1 on inducing PC12 cell differentiation, mGLP-1 induced PC12 cell differentiation with neurite outgrowth and increased the expression of growth-associated protein-43 and neuronal class III I^-tubulin, and significantly increased cyclic adenosine monophosphate level. No significant difference was found between mGLP-1 and nGLP-I. The results indicate that mGLP-1 activates the GLP-1 receptor, induces PC12 cell differentiation, and has neurotrophic effects.

Blood F_2-isoprostanes are significantly associated with abnormalities of lipid status in rats with steatosis

AIM: To investigate oxidative stress and lipid peroxi-dation in hepatic steatosis and the underlying implica-tions in pathological mechanisms of non-alcoholic fatty liver disease (NAFLD). METHODS: F_2-isoprostanes (iPF2α-) in blood and liver samples from steatotic (n = 9) and control (n = 7) rats were measured as in vivo marker of lipid peroxida-tion by a mass spectrometric approach. The lipid pro-fi le and endogenous antioxidant status (SOD and CAT) in the rats were also analyzed. RESULTS: Signifi cantly higher levels of iPF2α-(mean 3.47 vs 2.40 pmol/mg tissue, P = 0.004) and lower activities of SOD (mean 1.26 U vs 1.40 U, P < 0.001) and CAT (mean 1026.36 U/mg vs 1149.68 U/mg pro-tein, without signifi cance) were observed in the livers of steatotic rats. Plasma total iPF2α-was signifi cantly correlated with the abnormalities of blood lipids as well as alanine aminotransferase (ALT) levels in the rats with simple steatosis, whereas no similar tendencies were observed in the control rats. CONCLUSION: Enhancement of hepatic oxidative imbalance occurring at the steatotic stage of NAFLD suggests a possibility that manifestation of the local ⅢⅢⅢoxidative damage precedes that of systemic oxidative imbalance. Predominant metabolic features of the in-creased lipid peroxidation further suggest a close asso-ciation of the oxidative imbalance and the dyslipidemia with functional deterioration of the steatotic liver. The fi ndings need to be further evaluated, especially in hu-man studies.

Unexpected expression of heat-activated transient receptor potential(TRP)channels in winter torpid bats and cold-activated TRP channels in summer active bats

The ability to sense temperature changes is crucial for mammalian survival.Mammalian thermal sensing is primarily carried out by thermosensitive transient receptor potential channels(Thermo-TRPs).Some mammals hibernate to survive cold winter conditions,during which time their body temperature fluctuates dramatically.However,the underlying mechanisms by which these mammals regulate thermal responses remain unclear.Using quantitative real-time polymerase chain reaction(qRT-PCR)and the Western blotting,we found that Myotis ricketti bats had high levels of heat-activated TRPs(e.g.,TRPV1 and TRPV4)during torpor in winter and cold-activated TRPs(e.g.,TRPM8 and TRPC5)during active states in summer.We also found that laboratory mice had high mRNA levels of cold-activated TRPs(e.g.,Trpm8 and Trpc5)under relatively hot conditions(i.e.,40°C).These data suggest that small mammals up-regulate the expression of cold-activated TRPs even under warm or hot conditions.Binding site analysis showed that some homeobox(HOX)transcription factors(TFs)regulate the expression of hot-and cold-activated TRP genes and that some TFs of the Pit-Oct-Unc(POU)family regulate warm-sensitive and cold-activated TRP genes.The dual-luciferase reporter assay results demonstrated that TFs HOXA9,POU3F1,and POU5F1 regulate TRPC5 expression,suggesting that Thermo-TRP genes are regulated by multiple TFs of the HOX and POU families at different levels.This study provides insights into the adaptive mechanisms underlying thermal sensing used by bats to survive hibernation.

Executive and Non-Executive Functions in Attention Deficit Hyperactivity Disorder of the Inattentive Type (ADHD-I): A Cognitive Profile

Objective: This study examined the hypothesis that individuals with attention deficit hyperactivity disorder, predominantly inattentive type (ADHD-I), show both executive function (EF) deficits and non-EF deficits. Method: A group with ADHD-I (n = 16) and a paired control group (n = 21) completed a battery of tasks covering the major domains of EF (planning, working memory, flexibility and inhibition) and non-EF (alertness, divided attention, flexibility, sustained attention, visual field and visual scanning). Results: EF impairments in planning, spatial working memory, flexibility, and inhibition as well as non-EF impairments in divided attention, flexibility, sustained attention and visual scanning were observed in the ADHD-I group. Conclusion: Our results do not support the traditional model of ADHD. Given that neither EF nor non-EF tests typically distinguish ADHD-I from ADHD-C, alternative methodologies are required to confirm the validity of ADHD subtypes in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.

Arg-Ser-⁷⁷⁵, ⁷⁹²and ⁸²³in Spacer Region of ADAMTS-18 Is Critical for Thrombin Cleavage

Cleavage of ADAMTS-18 by thrombin represents a new mechanism of platelet thrombus clearance via the release of active ~45-kDa C-terminal fragments that induces oxidative platelet fragmentation. The exact cleavage sites remain unclear, but Arg (R)775/Ser (S)776 in spacer region of ADAMTS-18 has been shown to be one of the cleavage sites of thrombin. Here, we demonstrate that R792/S793 and R823/S824 are also thrombin cleavage sites by sequence analysis, amino acid mutation and mass spectrometry assay. All these cleavage sites are thrombin-specific and insensitive to other enzymes tested (e.g. cathepsin D or trypsin). Simultaneous mutation of R775, 792, 823 to S775, 792, 823 in ADAMTS-18 completely abrogated the cleavage by thrombin and the generation of active C-terminal 45-kDa fragments. Together with previous study, a total of three thrombin-specific cleavage sites have been identified in spacer region of ADAMTS-18.

Global cold-chain related SARS-CoV-2 transmission identified by pandemic-scale phylogenomics

DEAR EDITOR,The COVID-19 pandemic caused by SARS-CoV-2 continues to pose a tremendous threat to human society. SARS-CoV-2is airborne and transmits primarily through social contact;however, whether cold chain-related transmission has occurred remains highly debated(Han & Liu, 2022;Lewis,2021;Ma et al., 2021;Mallapaty et al., 2021;Pang et al.,2020;Wu et al., 2021). Here, we present a novel method and identify two transmission routes based on lineage-specific reductions in the SARS-CoV-2 evolutionary rate.

S3A-2 The Effect of PHA-543613 on Memory Disorders in Presenilin1 and Presenilin2 Conditional Double Knockout Mice

The mutation in the amyloid-beta precursor protein(APP)and presenilin genes(PSEN1 and PSEN2)cause autosomal dominant Alzheimer’s diease(ADAD)which is typically associated with early-onset familial Alzheimer’s disease(FAD),however,the mechanism by which presenilin mutations cause memory disorders and neurodegeneration remains poorly understood.In the present study,using Presenilin-1 and Presenilin-2 double knockout mice(cDKO mice),we observed that the impaired spatial reference memory,spatial working memory and contextual fear memory in cDKO mice.Consistently,deficits of basal synaptic transmission and LTP formation,as well as down-regulation of PI3K/Akt signaling pathway at hippocampus in cDKO mice.Furthermore,we found the expression levels ofα7-nicotinic ACh receptors(α7nAChRs),NMDAR and AMPAR composition subunits,which related to synaptic plasticity and memory,were decreased at hippocampus in cDKO mice.Importantly,all above deficits could be reversed byα7nAChR agonist PHA-543613.Taken together,our results indicate that knockout of PS1 and PS2 can disrupt the function ofα7nAChR,thereby down-regulate activation of PI3K/Akt signaling pathway,reduce the synaptic expression levels of NMDAR and AMPAR composition subunits at hippocampus,consequently cause neuronal apoptosis,disrupt basal synaptic transmission and LTP formation at hippocampus,fi nally impair hippocampal-dependent memory.

Shedding light on gene therapy of Parkinson’s disease in non-human primates

Parkinson’s disease(PD)is a progressive neurodegeneration disease initially described by James Parkinson.It is typically diagnosed based on clinical features such as bradykinesia,resting tremor,rigidity,and,in later stages,postural instability.Epidemiologically,the prevalence of PD ranges from 5 to over 35 cases per 100,000 population,with the majority affecting individuals aged 50 years or older.The risk increases with age,particularly in males.Various factors,including genetics,lifestyle,specific environmental influences,and geometry,contribute to the disease.

Metformin inhibits food intake and neuropeptide Y gene expression in the hypothalamus

Metformin may reduce food intake and body weight, but the anorexigenic effects of metformin are still poorly understood. In this study, Sprague-Dawley rats were administered a single intracere- broventricular dose of metformin and compound C, in a broader attempt to investigate the regula- tory effects of metformin on food intake and to explore the possible mechanism. Results showed that central administration of metformin significantly reduced food intake and body weight gain, par- ticularly after 4 hours. A reduction of neuropeptide Y expression and induction of AMP-activated protein kinase phosphorylation in the hypothalamus were also observed 4 hours after metformin administration, which could be reversed by compound C, a commonly-used antagonist of AMP-activated protein kinase. Furthermore, metformin also improved lipid metabolism by reducing plasma low-density lipoprotein. Our findings suggest that under normal physiological conditions, central regulation of appetite by metformin is related to a decrease in neuropeptide Y gene expres- sion, and that the activation of AMP-activated protein kinase may simply be a response to the anorexigenic effect of metformin.

A new dimeric furanocoumarin from Notopterygium incisum

A new dimeric psoralen-type furanocoumarin, notopterol-（18-O-20＇）-notopol （1）, was isolated from Notopterygium incisum for the first time and its structure was elucidated by spectroscopic methods.

Gene expression by simian virus 40 large Tantigen-induced medulloblastomas in mice

Signaling pathways known to have components with mutations in human medulloblastoma include sonic hedgehog, Wnt/beta-catenin and insulin-like growth factor. Microarray analysis was applied to examine the gene expression changes in medulloblastomas of pTet-on/pTRE-SV40Tag transgenic mice. Altogether, 14 112 genes were detectable, including 152 genes with significantly different expression levels. These genes were associated with immunity, the cell cycle, signal transduction, cytoskeleton and metabolism. To further confirm the microarray data, real-time polymerase chain reactions were used to examine the expression changes of genes related to sonic hedgehog, Wnt/beta-catenin and insulin-like growth factor signal pathways. Immunohistochemistry detected insulin receptor substrate-1 in the nuclei of brain tumor tissue cells from pTet-on/pTRE-SV40Tag transgenic mice, suggesting that SV40 large T antigen may activate the insulin-like growth factor signal pathway to promote tumorigenesis.

3-[3-(3-florophenyl-2-propyn-1-ylthio)-1,2,5-thiadiazol-4-yl]-1,2,5,6-tetrahydro-1-methylpyridine oxalate,a novel xanomeline derivative,improves neural cells proliferation and survival in adult mice

The present study analyzed the influence of 3-[3-（3-florophenyl-2-propyn-l-ylthio）-1, 2, 5-thiadiazol-4-yl]-1, 2, 5, 6-tetrahydro-l-methylpyridine oxalate （EUK1001）, a novel xanomeline derivative of the M1/M4 receptor agonist, on hippocampal neurogenesis in adult C57BL6 mice. Results showed that 15-day EUK1001 treatment via intraperitoneal injection promoted neural cell proliferation in the dentate gyrus, although cell differentiation did not change. The majority of bromodeoxyuridine-positive cells co-expressed the immature neuronal marker doublecortin. In addition, the level of neurogenesis in the subventricular zone was not altered. Brain-derived neurotrophic factor mRNA expression was up-regulated following EUK1001 treatment, but no change was observed in expression of camp-responsive element binding protein 1, paired box gene 6, vascular endothelial growth factor alpha, neurogenic differentiation factor 1, and wingless-related mouse mammary tumor virus integration site 3A mRNA. These experimental findings indicated that EUK1001 enhanced proliferation and survival of hippocampal cells, possibly by increasing brain-derived neurotrophic factor expression.

Advances in the Pathogenesis of Alzheimer’s Disease:Focusing on Tau-Mediated Neurodegeneration

In addition to senile plaques and cerebral amyloid angiopathy,the hyperphosphorylation of tau protein and formation of intraneuronal neurofibrillary tangles(NFTs)represents another neuropathological hallmark in AD brain.Tau is a microtubule-associated protein and localizes predominantly in the axons of neurons with the primary function in maintaining microtubules stability.When the balance between tau phosphorylation and dephosphorylation is changed in favor of the former,tau is hyperphosphorylated and the level of the free tau fractions elevated.The hyperphosphorylation of tau protein and formation of NFTs represent a characteristic neuropathological feature in AD brain.We have discussed the role of Aβin AD in our previous review,this review focused on the recent advances in tau-mediated AD pathology,mainly including tau hyperphosphorylation,propagation of tau pathology and the relationship between tau and Aβ.

Advances in the pathogenesis of Alzheimer’s disease:a re-evaluation of amyloid cascade hypothesis

Alzheimer’s disease(AD)is a common neurodegenerative disease characterized clinically by progressive deterioration of memory,and pathologically by histopathological changes including extracellular deposits of amyloid-beta(A-beta)peptides forming senile plaques(SP)and the intracellular neurofibrillary tangles(NFT)of hyperphosphorylated tau in the brain.This review focused on the new developments of amyloid cascade hypothesis with details on the production,metabolism and clearance of A-beta,and the key roles of some important A-beta-related genes in the pathological processes of AD.The most recent research advances in genetics,neuropathology and pathogenesis of the disease were also discussed.

PINK1 kinase dysfunction triggers neurodegeneration in the primate brain without impacting mitochondrial homeostasis

In vitro studies have established the prevalent theory that the mitochondrial kinase PINK1 protects neurodegeneration by removing damaged mitochondria in Parkinson's disease(PD).However,difficulty in detecting endogenous PINK1 protein in rodent brains and cell lines has prevented the rigorous investigation of the in vivo role of PINK1.Here we report that PINK1 kinase form is selectively expressed in the human and monkey brains.CRISPR/Cas9-mediated deficiency of PINK1 causes similar neurodegeneration in the brains of fetal and adult monkeys as well as cultured monkey neurons without affecting mitochondrial protein expression and morphology.Importantly,PINK1 mutations in the primate brain and human cells reduce protein phosphorylation that is important for neuronal function and survival.Our findings suggest that PINK1 kinase activity rather than its mitochondrial function is essential for the neuronal survival in the primate brains and that its kinase dysfunction could be involved in the pathogenesis of PD.

Correlation Between Brain Activation Changes and Cognitive Improvement Following Cognitive Remediation Therapy in Schizophrenia： An Activation Likelihood Estimation Meta-analysis

Background：Several studies using functional magnetic resonance imaging （fMRI） and positron emission tomography （PET） have indicated that cognitive remediation therapy （CRT） might improve cognitive function by changing brain activations in patients with schizophrenia.However,the results were not consistent in these changed brain areas in different studies.The present activation likelihood estimation （ALE） meta-analysis was conducted to investigate whether cognitive function change was accompanied by the brain activation changes,and where the main areas most related to these changes were in schizophrenia patients after CRT.Analyses of whole-brain studies and whole-brain ＋ region of interest （ROI） studies were compared to explore the effect of the different methodologies on the results.Methods：A computerized systematic search was conducted to collect fMRI and PET studies on brain activation changes in schizophrenia patients from pre-to post-CRT.Nine studies using fMRI techniques were included in the meta-analysis.Ginger ALE 2.3.1 was used to perform meta-analysis across these imaging studies.Results：The main areas with increased brain activation were in frontal and parietal lobe,including left medial frontal gyrus,left inferior frontal gyrus,right middle frontal gyrus,right postcentral gyrus,and inferior parietal lobule in patients after CRT,yet no decreased brain activation was found.Although similar increased activation brain areas were identified in ALE with or without ROI studies,analysis including ROI studies had a higher ALE value.Conclusions：The current findings suggest that CRT might improve the cognition of schizophrenia patients by increasing activations of the frontal and parietal lobe.In addition,it might provide more evidence to confirm results by including ROI studies in ALE meta-analysis.

GABAergic Interneurons are Required for Generation of Slow CA1 Oscillation in Rat Hippocampus

Neuronal oscillations are fundamental to hip- pocampal function. It has been shown that GABAergic interneurons make an important contribution to hippocampal oscillations, but the underlying mechanism is not well understood. Here, using whole-cell recording in the complete hippocampal formation isolated from rats at postnatal days 14-18, we showed that GABAA receptormediated activity enhanced the generation of slow CA1 oscillations. In vitro, slow oscillations （0.5-1.5 Hz） were generated in CA1 neurons, and they consisted primarily of excitatory rather than inhibitory membrane-potential changes. These oscillations were greatly reduced by blocking GABAA receptor-mediated activity with bicuculline and were enhanced by increasing such activity with midazolam, suggesting that interneurons are required for oscillation generation. Consistently, CA1 fast-spiking interneurons were found to generate action potentials usually preceding those in CA1 pyramidal cells. These findings indicate a GABAA receptor-based mechanism for the generation of the slow CA1 oscillation in the hippocampus.

Dependence of Generation of Hippocampal CAI Slow Oscillations on Electrical Synapses

Neuronal oscillations in the hippocampus are critical for many brain functions including learning and memory.The underlying mechanism of oscillation generation has been extensively investigated in terms of chemical synapses and ion channels.Recently,electrical synapses have also been indicated to play important roles,as reported in various brain areas in vivo and in brain slices.However,this issue remains to be further clarified,including in hippocampal networks.Here,using the completely isolated hippocampus,we investigated in vitro the effect of electrical synapses on slow CA1 oscillations(0.5 Hz-1.5 Hz)generated intrinsically by the hippocampus.We found that these oscillations were totally abolished by bath application of a general blocker of gap junctions(carbenoxolone)or a specific blocker of electrical synapses(mefloquine),as determined by whole-cell recordings in both CA1 pyramidal cells and fast-spiking cells.Our findings indicate that electrical synapses are required for the hippocampal generation of slow CA1 oscillations.