Hippocampal circAnk3 Deficiency Causes Anxiety-like Behaviors and Social Deficits by Regulating the miR-7080-3p/IQGAP1 Pathway in Mice.

BACKGROUND: Circular RNAs are highly enriched in the synapses of the mammalian brain and play important roles in neurological function by acting as molecular sponges of microRNAs. circAnk3 is derived from the 11th intron of the ankyrin-3 gene, Ank3, a strong genetic risk factor for neuropsychiatric disorders; however, the function of circAnk3 remains elusive. In this study, we investigated the function of circAnk3 and its downstream regulatory network for target genes in the hippocampus of mice. METHODS: The DNA sequence from which circAnk3 is generated was modified using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/Cas9) technology, and neurobehavioral tests (anxiety and depression-like behaviors, social behaviors) were performed in circAnk3+/- mice. A series of molecular and biochemical assays were used to investigate the function of circAnk3 as a microRNA sponge and its downstream regulatory network for target genes. RESULTS: circAnk3+/- mice exhibited both anxiety-like behaviors and social deficits. circAnk3 was predominantly located in the cytoplasm of neuronal cells and functioned as a miR-7080-3p sponge to regulate the expression of Iqgap1. Inhibition of miR-7080-3p or restoration of Iqgap1 in the hippocampus ameliorated the behavioral deficits of circAnk3+/- mice. Furthermore, circAnk3 deficiency decreased the expression of the NMDA receptor subunit GluN2a and impaired the structural plasticity of dendritic synapses in the hippocampus. CONCLUSIONS: Our results reveal an important role of the circAnk3/miR-7080-3p/IQGAP1 axis in maintaining the structural plasticity of hippocampal synapses. circAnk3 might offer new insights into the involvement of circular RNAs in neuropsychiatric disorders.

Integrated lipidomic and transcriptomic analysis reveals clarithromycin-induced alteration of glycerophospholipid metabolism in the cerebral cortex of mice.

Clarithromycin (CLA) has been widely used in the treatment of bacterial infection. Research reveals the adverse effects on the central nervous system among patients receiving CLA treatment; whereas, a relevant underlying mechanism remains considerably unclear. According to our research, an integrated lipidomic and transcriptomic analysis was applied to explore the effect of CLA on neurobehavior. CLA treatment caused anxiety-like behaviors dose-dependently during open field as well as elevated plus maze trials on mice. Transcriptomes and LC/MS-MS-based metabolomes were adopted for investigating how CLA affected lipidomic profiling as well as metabolic pathway of the cerebral cortex. CLA exposure greatly disturbed glycerophospholipid metabolism and the carbon chain length of fatty acids. By using whole transcriptome sequencing, we found that CLA significantly downregulated the mRNA expression of CEPT1 and CHPT1, two key enzymes involved in the synthesis of glycerophospholipids, supporting the findings from the lipidomic profiling. Also, CLA causes changes in neuronal morphology and function in vitro, which support the existing findings concerning neurobehavior in vivo. We speculate that altered glycerophospholipid metabolism may be involved in the neurobehavioral effect of CLA. Our findings contribute to understanding the mechanisms of CLA-induced adverse effects on the central nervous system. 1. Clarithromycin treatment caused anxiety-like behavior with dose-dependent response both in the open field and elevated plus maze test in mice; 2. Clarithromycin exposing predominately disturbed the metabolism of glycerophospholipids in the cerebral cortex of mice; 3. Clarithromycin application remarkably attenuated CEPT1 and CHPT1 gene expression, which participate in the last step in the synthesis of glycerophospholipids; 4. The altered glycerophospholipid metabolomics may be involved in the abnormal neurobehavior caused by clarithromycin.

Neonatal exposure to sevoflurane induces adolescent neurobehavioral dysfunction by interfering with hippocampal glycerophoslipid metabolism in rats.

Sevoflurane exposure in the neonatal period causes long-term developmental neuropsychological dysfunction, including memory impairment and anxiety-like behaviors. However, the molecular mechanisms underlying such effects have not been fully elucidated. In this study, we investigated the effect of neonatal exposure to sevoflurane on neurobehavioral profiles in adolescent rats, and applied an integrated approach of lipidomics and proteomics to investigate the molecular network implicated in neurobehavioral dysfunction. We found that neonatal exposure to sevoflurane caused cognitive impairment and social behavior deficits in adolescent rats. Lipidomics analyses revealed that sevoflurane significantly remodeled hippocampal lipid metabolism, including lysophatidylcholine (LPC) metabolism, phospholipid carbon chain length and carbon chain saturation. Through a combined proteomics analysis, we found that neonatal exposure to sevoflurane significantly downregulated the expression of lysophosphatidylcholine acyltransferase 1 (LPCAT1), a key enzyme in the regulation of phospholipid metabolism, in the hippocampus of adolescent rats. Importantly, hippocampal LPCAT1 overexpression restored the dysregulated glycerophospholipid (GP) metabolism and alleviated the learning and memory deficits caused by sevoflurane. Collectively, our evidence that neonatal exposure to sevoflurane downregulates LPCAT1 expression and dysregulates GP metabolism in the hippocampus, which may contribute to the neurobehavioral dysfunction in the adolescent rats.

ß-hydroxybutyrate reduces reinstatement of cocaine conditioned place preference through hippocampal CaMKII-α ß-hydroxybutyrylation.

Studies have shown the therapeutic effects of a ketogenic diet (KD) on epilepsy, but the effect of a KD on drug reinstatement is largely unclear. This study aims to investigate whether KD consumption possesses therapeutic potential for cocaine reinstatement and the molecular mechanism. We find that a KD significantly reduces cocaine-induced reinstatement in mice, which is accompanied by a markedly elevated level of ß-hydroxybutyrate (ß-OHB), the most abundant ketone body, in the hippocampus. The underlying mechanism is that ß-OHB posttranslationally modifies CaMKII-α with ß-hydroxybutyrylation, resulting in significant inhibition of T286 autophosphorylation and downregulation of CaMKII activity. Collectively, our results reveal that ß-hydroxybutyrylation is a posttranslational modification of CaMKII-α that plays a critical role in mediating the effect of KD consumption in reducing cocaine reinstatement.

Synapse differentiation-induced gene 1 regulates stress-induced depression through interaction with the AMPA receptor GluA2 subunit of nucleus accumbens in male mice.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are key regulators during the process of synaptic plasticity in major depression disorder (MDD). Synapse differentiation-induced gene 1 (SynDIG1) functions as an atypical AMPAR auxiliary subunit and regulates synaptic AMPAR content; however, the role of SynDIG1 in MDD remains elusive. In this study, we found that the SynDIG1 expression was significantly increased in the neurons of the nucleus accumbens (NAc) of male mice after chronic social defeat stress (CSDS). CSDS enhanced SynDIG1-GluA2 binding and promoted the surface expression of AMPAR subunit GluA2 in the NAc. Knockdown of SynDIG1 decreased the surface expression of GluA2 and reversed the alteration of dendrite spines in the neurons, eventually alleviating the depressive-like behaviors of the stressed mice. Moreover, intra-NAc injection of IP12, a specific peptide to disrupt the interaction of SynDIG1 with GluA2, rescued depressive-like behaviors. Collectively, SynDIG1 regulates the surface expression of GluA2 and dendritic remodeling in the NAc of male mice under CSDS, thus mediating the depressive-like behaviors.

mTOR regulates cocaine-induced behavioural sensitization through the SynDIG1-GluA2 interaction in the nucleus accumbens.

Behavioral sensitization is a progressive increase in locomotor or stereotypic behaviours in response to drugs. It is believed to contribute to the reinforcing properties of drugs and to play an important role in relapse after cessation of drug abuse. However, the mechanism underlying this behaviour remains poorly understood. In this study, we showed that mTOR signaling was activated during the expression of behavioral sensitization to cocaine and that intraperitoneal or intra-nucleus accumbens (NAc) treatment with rapamycin, a specific mTOR inhibitor, attenuated cocaine-induced behavioural sensitization. Cocaine significantly modified brain lipid profiles in the NAc of cocaine-sensitized mice and markedly elevated the levels of phosphatidylinositol-4-monophosphates (PIPs), including PIP, PIP2, and PIP3. The behavioural effect of cocaine was attenuated by intra-NAc administration of LY294002, an AKT-specific inhibitor, suggesting that PIPs may contribute to mTOR activation in response to cocaine. An RNA-sequencing analysis of the downstream effectors of mTOR signalling revealed that cocaine significantly decreased the expression of SynDIG1, a known substrate of mTOR signalling, and decreased the surface expression of GluA2. In contrast, AAV-mediated SynDIG1 overexpression in NAc attenuated intracellular GluA2 internalization by promoting the SynDIG1-GluA2 interaction, thus maintaining GluA2 surface expression and repressing cocaine-induced behaviours. In conclusion, NAc SynDIG1 may play a negative regulatory role in cocaine-induced behavioural sensitization by regulating synaptic surface expression of GluA2.

Synthesis, biological, and structural explorations of a series of µ-opioid receptor (MOR) agonists with high G protein signaling bias.

Biased agonism refers to the ability of compounds to drive preferred signaling pathways and avoid adverse signaling pathways in a ligand-dependent manner for some G-protein-coupled receptors. It is thought that the separation of therapeutic efficacy (e.g., analgesia) from adverse effects (e.g., respiration depression) can be achieved through the design of biased MOR agonists and one example is the recently approved MOR biased agonist oliceridine (TRV130). However, oliceridine only demonstrates modest beneficial effects as compared to other opioids in terms of therapeutic/adverse effect balance. One possibility attributable to the modest success of oliceridine is its limited bias, and as such developing MOR ligands with a more biased agonism profile could in theory further improve the beneficial effects of the ligands. Here, we rationally designed and synthesized a series of derivatives as potent highly biased MOR agonists (19a-v) through the modification and structure-activity relationship study of TRV130. This novel synthetic molecule, LPM3480392 (19m), demonstrated improved in vitro biased agonism (EC50 = 0.35 nM, Emax = 91.4%) with no measured ß-arrestin recruitment (EC50 > 30000 nM, Emax = 1.6%), good brain penetration (B/P ratio = 4.61, 0.25 h post-IV dosing 2.0 mg/kg), a favorable pharmacokinetic profile (distribution volume = 10766 mL/kg, t1/2 = 1.9 h) and produced potent antinociceptive effect with reduced respiratory suppression (sO2(%) = 92.17, 0.32 mg/kg, SC) as compared to TRV130. LPM3480392 has completed preclinical studies and is currently under clinical development (CTR20210370) as an analgesic for the treatment of moderate to severe pain.

Lipidomics Reveals Dysregulated Glycerophospholipid Metabolism in the Corpus Striatum of Mice Treated with Cefepime.

Cefepime exhibits a broad spectrum of antimicrobial activity and thus is a widely used treatment for severe bacterial infections. Adverse effects on the central nervous system (CNS) have been reported in patients treated with cefepime. Current explanation for the adverse neurobehavioral effect of cefepime is mainly attributed to its ability to cross the blood-brain barrier and competitively bind to the GABAergic receptor; however, the underlying mechanism is largely unknown. In this study, mice were intraperitoneally administered 80 mg/kg cefepime for different periods, followed by neurobehavioral tests and a brain lipidomic analysis. LC/MS-MS-based metabolomics was used to investigate the effect of cefepime on the brain lipidomic profile and metabolic pathways. Repeated cefepime treatment time-dependently caused anxiety-like behaviors, which were accompanied by reduced locomotor activity in the open field test. Cefepime profoundly altered the lipid profile, acyl chain length, and unsaturation of fatty acids in the corpus striatum, and glycerophospholipids accounted for a large proportion of those significantly modified lipids. In addition, cefepime treatment caused obvious alteration in the lipid-enriched membrane structure, neurites, mitochondria, and synaptic vesicles of primary cultured striatal neurons; moreover, the spontaneous electrical activity of striatal neurons was significantly reduced. Collectively, cefepime reprograms glycerophospholipid metabolism in the corpus striatum, which may interfere with neuronal structure and activity, eventually leading to aberrant neurobehaviors in mice.

Simvastatin Blocks Reinstatement of Cocaine-induced Conditioned Place Preference in Male Mice with Brain Lipidome Remodeling.

Drug-associated reward memories are conducive to intense craving and often trigger relapse. Simvastatin has been shown to regulate lipids that are involved in memory formation but its influence on other cognitive processes is elusive. Here, we used a mass spectrometry-based lipidomic method to evaluate the impact of simvastatin on the mouse brain in a cocaine-induced reinstatement paradigm. We found that simvastatin blocked the reinstatement of cocaine-induced conditioned place preference (CPP) without affecting CPP acquisition. Specifically, only simvastatin administered during extinction prevented cocaine-primed reinstatement. Global lipidome analysis showed that the nucleus accumbens was the region with the greatest degree of change caused by simvastatin. The metabolism of fatty-acids, phospholipids, and triacylglycerol was profoundly affected. Simvastatin reversed most of the effects on phospholipids induced by cocaine. The correlation matrix showed that cocaine and simvastatin significantly reshaped the lipid metabolic pathways in specific brain regions. Furthermore, simvastatin almost reversed all changes in the fatty acyl profile and unsaturation caused by cocaine. In summary, pre-extinction treatment with simvastatin facilitates cocaine extinction and prevents cocaine relapse with brain lipidome remodeling.

4R Tau Modulates Cocaine-Associated Memory through Adult Dorsal Hippocampal Neurogenesis.

The development, persistence and relapse of drug addiction require drug memory that generally develops with drug administration-paired contextual stimuli. Adult hippocampal neurogenesis (AHN) contributes to cocaine memory formation; however, the underlying mechanism remains unclear. Male mice hippocampal expression of Tau was significantly decreased during the cocaine-associated memory formation. Genetic overexpression of four microtubule-binding repeats Tau (4R Tau) in the mice hippocampus disrupted cocaine memory by suppressing AHN. Furthermore, 4R Tau directly interacted with phosphoinositide 3-kinase (PI3K)-p85 and impaired its nuclear translocation and PI3K-AKT signaling, processes required for hippocampal neuron proliferation. Collectively, 4R Tau modulates cocaine memory formation by disrupting AHN, suggesting a novel mechanism underlying cocaine memory formation and provide a new strategy for the treatment of cocaine addiction.SIGNIFICANCE STATEMENT Drug memory that generally develops with drug-paired contextual stimuli and drug administration is critical for the development, persistence and relapse of drug addiction. Previous studies have suggested that adult hippocampal neurogenesis (AHN) plays a role in cocaine memory formation. Here, we showed that Tau was significantly downregulated in the hippocampus in the cocaine memory formation. Tau knock-out (KO) promoted AHN in the hippocampal dentate gyrus (DG), resulting in the enhanced memory formation evoked by cocaine-cue stimuli. In contrast, genetically overexpressed 4R Tau in the hippocampus disrupted cocaine-cue memory by suppressing AHN. In addition, 4R Tau interacted directly with phosphoinositide 3-kinase (PI3K)-p85 and hindered its nuclear translocation, eventually repressing PI3K-AKT signaling, which is essential for hippocampal neuronal proliferation.

Influence of Rare Earth Element (Y) on Microstructure and Corrosion Behavior of Hot Extrusion AZ91 Magnesium Alloy.

The influence of rare earth element (RE) Y on the microstructure and corrosion behavior of extruded AZ91 Mg alloy was surveyed via morphology characterization and corrosion performance measurements. The results indicate the corrosion resistance of the transversal section of AZ91 Mg alloy containing Y was improved compared with AZ91 Mg alloy without Y. The corrosion resistance of the longitudinal section of AZ91 Mg alloy with Y was lower than that of AZ91 Mg alloy without Y. The change of corrosion resistance can be attributed to the dispersion and volume fraction of the second phase, the effect of cathodic reduction rate, and the refined second phase.

Research on the Wear Behavior of the Fixed Cone Liner of a Cone Crusher Based on the Discrete Element Method.

Taking reducing the wear of the fixed cone liner of a cone crusher as the starting point, the movement and geometry parameters of the cone crusher are studied using the discrete element method. To improve the service life and working efficiency of the whole cone crusher. The UG model and discrete element Yade model of the cone crusher are established, and the different shapes of the tin ore are represented using Yade's preprocessor through eight different ways of particle combination and superposition. The static friction coefficient between the manganese ore and the cone crusher is studied and calibrated using the slope method. The relative error between the Yade and test results is 1.58%, and the calibration result is 0.44. The repose angle of the manganese ore is studied using the collapse method. The repose angle increases with the increase of the static friction coefficient and the dynamic friction coefficient, but the change trend is different. The effect of the dynamic friction coefficient on the repose angle is obviously greater than that of the static friction coefficient. The dynamic friction coefficient obtained by Yade is 0.042. Taking the swing distance, rotating speed, and bottom angle of the fixed cone as the orthogonal experimental factors of Yade, the regression equation of the fixed cone liner was obtained through the nonlinear processing of SPSS 25.0. According to Matlab R2017b, the influences of the swinging distance, rotating speed, and bottom angle of the fixed cone on the fixed cone liner are obtained. According to Yade's research results, the order of the influence degree of liner wear is: the rotating speed of moving cone, the swinging distance of the fixed cone, and the base angle of fixed rotation. When the swinging distance of the fixed cone is 146 mm, the rotating speed of the moving cone is 198 rpm, the fixed rotation bottom angle is 28°, and the minimum value of the liner wear is 23 mm. Yade's results are consistent with the change trend of the wear amount of the bushing obtained from the test. The research results show the correctness of using the Yade method to study the wear of the fixed cone liner of a cone crusher, which provides a theoretical basis for reducing the wear of the fixed cone liner of a cone crusher, and puts forward a new method to study the wear of relevant parts of a fixed cone crusher. At the same time, the research results are of great significance for achieving energy-saving in mining enterprises.

[Relationship between condylar marrow signal abnormalities and temporomandibular joint internal derangement].

OBJECTIVE: To investigate the relationship between condylar marrow signal abnormalities and temporomandibular joint internal derangement (TMJID). METHODS: Oblique sagittal T1 weighted MR imaging at closed and open mouth and Oblique sagittal T2 weighted MR imaging at closed mouth were obtained from 88 joints of 44 patients suffering from TMD. Condylar marrow signal abnormalities were reviewed and classified into bone marrow edema pattern (hypointense T1, hyperintense T2), sclerosis pattern (hypointense T1 and hypointense T2) and combined edema and sclerosis pattern. RESULTS: Of 88 joints, 13 (14.8%) joints showed condylar marrow signal abnomalities, among which 11 belonged to edema pattern and, 1 was sclerosis pattern and the other was the combined patten. Of 13 joints with condylar marrow signal abnomalities, 11 (84.6%) had TMJID. Of 75 joints with normal marrow signal, 25 (33.3%) joints had TMJID. There was significant correlation between condylar marrow signal abnormalities and TMJID (P < 0.05). CONCLUSION: Disc displacement is one of the factors inducing condylar marrow signal abnormalities. The pathological process from disc displacement to osteonecrosis requires further study.

[Relationship between condylar marrow signal abnormalities and temporomandibular joint pain].

PURPOSE: To investigate the relationship between condylar marrow signal abnormalities and joint pain. METHODS: Oblique sagittal T1 and T2 weighted MR imaging at closed mouth was obtained from 88 joints of 44 patients who complained of unilateral TMJ pain. The condylar marrow signal of pain-free side served as self-control. All patients rated their pain levels by a visual analogue scale (VAS). RESULTS: Of 44 painful joints, 11(25% joints showed condylar marrow signal abnormalities, all of which were edema pattern. While there had condylar marrow signal abnormalities only in 2 (4.5%) of 44 pain-free TMJs. There was significant correlation between joint pain and condylar marrow signal abnormalities (P<0.01). The VAS score of patients with and without condylar marrow signal abnormalities was respectively 39.5+/-27.5 and 42.6+/-21.9, There was no correlation between them (P=0.696). CONCLUSION: Temporomandibular joint pain is closely correlated with condylar marrow signal abnormalities, but the pain degree has no association with it.