Impaired Cognitive Function and Altered Hippocampal Synaptic Plasticity in Mice Lacking Dermatan Sulfotransferase Chst14/D4st1

Inhibition of CSPG-PTPσ Activates Autophagy Flux and Lysosome Fusion, Aids Axon and Synaptic Reorganization in Spinal Cord Injury

Chondroitin sulfate proteoglycans (CSPGs) and proteoglycan receptor protein tyrosine phosphatase σ (PTPσ) play a critical role in the pathology of spinal cord injury (SCI). CSPGs can be induced by autophagy inhibition in astrocyte. However, CSPG's impact on autophagy and its role in SCI is still unknown. We investigate intracellular sigma peptide (ISP) targeting PTPσ, its effects on autophagy, and synaptic reorganization in SCI. We found that ISP increased the level of autophagosome marker LC3B-II/I and decreased autophagosome degradation marker p62 in SCI, suggesting activated autophagy flux. ISP restored autophagosome-lysosome fusion-related protein syntaxin 17 (STX17) and lysosome-associated membrane protein 2 (LAMP2), indicating activated autophagosome-lysosome fusion. ISP increased pre-synaptic marker synaptophysin (SYN) and postsynaptic density protein-95 (PSD-95) expression and improved excitatory synapse marker vesicular glutamate transporter 1 (VGLUT1) and SYN in SCI, suggesting improved synaptic reorganization. ISP promoted axon marker neurofilament and growth-related GAP-43 expression in SCI. ISP rescued a preserved number of motor neurons and improved neurobehavioral recovery after SCI. Our study extended the CSPG-PTPσ inhibition role in activating autophagy flux, axon and synaptic reorganization, and functional recovery in SCI.

Exome Sequencing Identified Susceptible Genes for High Residual Risks in Early-Onset Coronary Atherosclerotic Disease

AIMS

Despite the tremendous improvement in therapeutic medication and intervention for coronary atherosclerotic disease (CAD), residual risks remain. Exome sequencing enables identification of rare variants and susceptibility genes for residual risks of early-onset coronary atherosclerotic disease (EOCAD) with well-controlled conventional risk factors.

METHODS

We performed whole-exome sequencing of subjects who had no conventional risk factors, defined as higher body mass index, smoking, hypertension and dyslipidemia, screened from 1950 patients with EOCAD (age ≤ 45 years, at least 50% stenosis of coronary artery by angiography), and selected control subjects from 1006 elder (age ≥ 65 years) with < 30% coronary stenosis. Gene-based association analysis and clinical phenotypic comparison were conducted.

RESULTS

Subjects without defined conventional risk factors accounted for 4.72% of young patients. Totally, 6 genes might be associated with residual risk of EOCAD, namely CABP1 (OR = 22.19, p = 0.02), HLA-E (OR = 22.19, p = 0.02), TOE1 (OR = 33.6, p = 0.002), HPSE2 (OR = 11.1, p = 0.04), CHST14 (OR = 22.19, p = 0.02) as well as KLHL8 (OR = 22.19, p = 0.02). Phenotypic analysis displayed the levels of low-density lipoprotein cholesterol in carriers of mutations from CABP1, HLA-E, TOE1, and HPSE2 were significantly elevated compared to noncarriers. Notably, extracellular matrix-associated CHST14 and fibrinogen-associated KLHL8 both displayed possible correlation with increased neutrophil proportion and decreased monocyte percentage (both p < 0.05), exerting potential effects on the residual inflammatory risks of EOCAD.

CONCLUSION

The study identified six genes related to dyslipidemia and inflammation pathways with potential association with residual risk of EOCAD, which will contribute to precision-based prevention in these patients.

TRIAL REGISTRATION

The GRAND study was registered at www.

CLINICALTRIALS

gov on July 14, 2015, and the registry number is NCT02496858.

Sex and Region-Specific Disruption of Autophagy and Mitophagy in Alzheimer's Disease: Linking Cellular Dysfunction to Cognitive Decline

Macroautophagy and mitophagy are critical processes in Alzheimer's disease (AD), yet their links to behavioral outcomes, particularly sex-specific differences, are not fully understood. This study investigates autophagy (LC3B-II, SQSTM1) and mitophagy (BNIP3L, BNIP3, BCL2L13) markers in the cortex and hippocampus of male and female 3xTg-AD mice, using western blotting, transmission electron microscopy (TEM), and behavioral tests (novel object recognition and novel object placement). Significant sex-specific differences emerged: female 3xTg-AD mice exhibited autophagosome accumulation due to impaired degradation in the cortex, while males showed fewer autophagosomes, especially in the hippocampus, without significant degradation changes. TEM analyses demonstrated variations in mitochondrial and mitophagosome numbers correlated with memory outcomes. Females had enhanced mitophagy, with higher BNIP3L and BCL2L13 levels, whereas males showed elevated BNIP3 dimers. Cognitive deficits in females correlated with mitochondrial dysfunction in the cortex, while in males, higher LC3B-II levels associated positively with cognitive performance, suggesting protective autophagy effects. Using machine learning, we predicted mitophagosome and mitochondrial numbers based on behavioral data, pioneering a predictive approach to cellular outcomes in AD. These findings underscore the importance of sex-specific regulation of autophagy and mitophagy in AD and support personalized therapeutic approaches targeting these pathways. Integrating machine learning emphasizes its potential to advance neurodegenerative research.

Abstract Figure

The role of synaptic protein NSF in the development and progression of neurological diseases

This document provides a comprehensive examination of the pivotal function of the N-ethylmaleimide-sensitive factor (NSF) protein in synaptic function. The NSF protein directly participates in critical biological processes, including the cyclic movement of synaptic vesicles (SVs) between exocytosis and endocytosis, the release and transmission of neurotransmitters, and the development of synaptic plasticity through interactions with various proteins, such as SNARE proteins and neurotransmitter receptors. This review also described the multiple functions of NSF in intracellular membrane fusion events and its close associations with several neurological disorders, such as Parkinson's disease, Alzheimer's disease, and epilepsy. Subsequent studies should concentrate on determining high-resolution structures of NSF in different domains, identifying its specific alterations in various diseases, and screening small molecule regulators of NSF from multiple perspectives. These research endeavors aim to reveal new therapeutic targets associated with the biological functions of NSF and disease mechanisms.

Glycosaminoglycan microarrays for studying glycosaminoglycan-protein systems

More than 3000 proteins are now known to bind to glycosaminoglycans (GAGs). Yet, GAG-protein systems are rather poorly understood in terms of selectivity of recognition, molecular mechanism of action, and translational promise. High-throughput screening (HTS) technologies are critically needed for studying GAG biology and developing GAG-based therapeutics. Microarrays, developed within the past two decades, have now improved to the point of being the preferred tool in the HTS of biomolecules. GAG microarrays, in which GAG sequences are immobilized on slides, while similar to other microarrays, have their own sets of challenges and considerations. GAG microarrays are rapidly becoming the first choice in studying GAG-protein systems. Here, we review different modalities and applications of GAG microarrays presented to date. We discuss advantages and disadvantages of this technology, explain covalent and non-covalent immobilization strategies using different chemically reactive groups, and present various assay formats for qualitative and quantitative interpretations, including selectivity screening, binding affinity studies, competitive binding studies etc. We also highlight recent advances in implementing this technology, cataloging of data, and project its future promise. Overall, the technology of GAG microarray exhibits enormous potential of evolving into more than a mere screening tool for studying GAG - protein systems.

Prenatal and postnatal methamphetamine exposure alters prefrontal cortical gene expression and behavior in mice

Methamphetamine is a highly abused psychostimulant that substantially impacts public health. Prenatal and postnatal methamphetamine exposure alters gene expression, brain development, and behavior in the offspring, although the underlying mechanisms are not fully defined. To assess these adverse outcomes in the offspring, we employed a mouse model of prenatal and postnatal methamphetamine exposure. Juvenile offspring were behaviorally assessed on the open field, novel object recognition, Y-maze, and forced swim tests. In addition, RNA sequencing was used to explore potential alterations in prefrontal cortical gene expression. We found that methamphetamine-exposed mice exhibited decreased locomotor activity and impaired cognitive performance. In addition, differential expression of genes involved in neurotransmission, synaptic plasticity, and neuroinflammation were found with notable changes in dopaminergic signaling pathways. These data suggest potential neural and molecular mechanisms underlying methamphetamine-exposed behavioral changes. The altered expression of genes involved in dopaminergic signaling and synaptic plasticity highlights potential targets for therapeutic interventions for substance abuse disorders and related psychiatric complications.

Astrotactin 2 (ASTN2) regulates emotional and cognitive functions by affecting neuronal morphogenesis and monoaminergic systems

Astrotactin2 (ASTN2) regulates neuronal migration and synaptic strength through the trafficking and degradation of surface proteins. Deletion of ASTN2 in copy number variants has been identified in patients with schizophrenia, bipolar disorder, and autism spectrum disorder in copy number variant (CNV) analysis. Disruption of ASTN2 is a risk factor for these neurodevelopmental disorders, including schizophrenia, bipolar disorder, autism spectrum disorder, and attention deficit hyperactivity disorder. However, the importance of ASTN2 in physiological functions remains poorly understood. To elucidate the physiological functions of ASTN2, we investigated whether deficiency of ASTN2 affects cognitive and/or emotional behaviors and neurotransmissions using ASTN2-deficient mice. Astn2 knockout (KO) mice produced by CRISPR/Cas9 technique showed no obvious differences in physical characteristics and circadian rhythm. Astn2 KO mice showed increased exploratory activity in a novel environment, social behavior and impulsivity, or decreased despair-, anxiety-like behaviors and exploratory preference for the novel object. Some behavioral abnormalities, such as increased exploratory activity and impulsivity, or decreased exploratory preference were specifically attenuated by risperidone, but not by haloperidol. While, the both drugs did not affect any emotion-related behavioral abnormalities in Astn2 KO mice. Dopamine contents were decreased in the striatum, and serotonin or dopamine turnover were increased in the striatum, nucleus accumbens, and amygdala of Astn2 KO mice. In morphological analyses, thinning of neural cell layers in the hippocampus, reduction of neural cell bodies in the prefrontal cortex, and decrease in spine density and PSD95 protein in both tissues were observed in Astn2 KO mice. The present findings suggest that ASTN2 deficiency develops some emotional or cognitive impairments related to monoaminergic dysfunctions and abnormal neuronal morphogenesis with shrinkage of neuronal soma. ASTN2 protein may contribute to the pathogenic mechanism and symptom onset of mental disorders.

Effect and mechanism of acupuncture on Alzheimer's disease: A review

With the development trend of an aging society, Alzheimer's disease (AD) has become an urgent problem in the field of medicine worldwide. Cognitive impairment in AD patients leads to a decline in the ability to perform daily living and abnormalities in behavior and personality, causing abnormal psychiatric symptoms, which seriously affect the daily life of patients. Currently, mainly drug therapy is used for AD patients in the clinic, but a large proportion of patients will experience drug efficacy not working, and even some drugs bring severe sleep disorders. Acupuncture, with its unique concept and treatment method, has been validated through a large number of experiments and proved its reliability of acupuncture in the treatment of AD. Many advances have been made in the study of the neurobiological mechanisms of acupuncture in the treatment of AD, further demonstrating the good efficacy and unique advantages of acupuncture in the treatment of AD. This review first summarizes the pathogenesis of AD and then illustrates the research progress of acupuncture in the treatment of AD, which includes the effect of acupuncture on the changes of biochemical indicators in AD in vivo and the specific mechanism of action to exert the therapeutic effect. Changes in relevant indicators of AD similarly further validate the effectiveness of acupuncture treatment. The clinical and mechanistic studies of acupuncture in the treatment of AD are intensified to fit the need for social development. It is believed that acupuncture will achieve new achievements in the treatment of AD as research progresses.

Mouse Models of Musculocontractural Ehlers-Danlos Syndrome

Musculocontractural Ehlers-Danlos syndrome (mcEDS) is a subtype of EDS caused by mutations in the gene for carbohydrate sulfotransferase 14 (CHST14) (mcEDS-CHST14) or dermatan sulfate epimerase (DSE) (mcEDS-DSE). These mutations induce loss of enzymatic activity in D4ST1 or DSE and disrupt dermatan sulfate (DS) biosynthesis. The depletion of DS causes the symptoms of mcEDS, such as multiple congenital malformations (e.g., adducted thumbs, clubfeet, and craniofacial characteristics) and progressive connective tissue fragility-related manifestations (e.g., recurrent dislocations, progressive talipes or spinal deformities, pneumothorax or pneumohemothorax, large subcutaneous hematomas, and/or diverticular perforation). Careful observations of patients and model animals are important to investigate pathophysiological mechanisms and therapies for the disorder. Some independent groups have investigated Chst14 gene-deleted (Chst14-/-) and Dse-/- mice as models of mcEDS-CHST14 and mcEDS-DSE, respectively. These mouse models exhibit similar phenotypes to patients with mcEDS, such as suppressed growth and skin fragility with deformation of the collagen fibrils. Mouse models of mcEDS-CHST14 also show thoracic kyphosis, hypotonia, and myopathy, which are typical complications of mcEDS. These findings suggest that the mouse models can be useful for research uncovering the pathophysiology of mcEDS and developing etiology-based therapy. In this review, we organize and compare the data of patients and model mice.

Unraveling the phenotypic and genomic background of behavioral plasticity and temperament in North American Angus cattle

BACKGROUND

Longitudinal records of temperament can be used for assessing behavioral plasticity, such as aptness to learn, memorize, or change behavioral responses based on affective state. In this study, we evaluated the phenotypic and genomic background of North American Angus cow temperament measured throughout their lifetime around the weaning season, including the development of a new indicator trait termed docility-based learning and behavioral plasticity. The analyses included 273,695 and 153,898 records for yearling (YT) and cow at weaning (CT) temperament, respectively, 723,248 animals in the pedigree, and 8784 genotyped animals. Both YT and CT were measured when the animal was loading into/exiting the chute. Moreover, CT was measured around the time in which the cow was separated from her calf. A random regression model fitting a first-order Legendre orthogonal polynomial was used to model the covariance structure of temperament and to assess the learning and behavioral plasticity (i.e., slope of the regression) of individual cows. This study provides, for the first time, a longitudinal perspective of the genetic and genomic mechanisms underlying temperament, learning, and behavioral plasticity in beef cattle.

RESULTS

CT measured across years is heritable (0.38-0.53). Positive and strong genetic correlations (0.91-1.00) were observed among all CT age-group pairs and between CT and YT (0.84). Over 90% of the candidate genes identified overlapped among CT age-groups and the estimated effect of genomic markers located within important candidate genes changed over time. A small but significant genetic component was observed for learning and behavioral plasticity (heritability = 0.02 ± 0.002). Various candidate genes were identified, revealing the polygenic nature of the traits evaluated. The pathways and candidate genes identified are associated with steroid and glucocorticoid hormones, development delay, cognitive development, and behavioral changes in cattle and other species.

CONCLUSIONS

Cow temperament is highly heritable and repeatable. The changes in temperament can be genetically improved by selecting animals with favorable learning and behavioral plasticity (i.e., habituation). Furthermore, the environment explains a large part of the variation in learning and behavioral plasticity, leading to opportunities to also improve the overall temperament by refining management practices. Moreover, behavioral plasticity offers opportunities to improve the long-term animal and handler welfare through habituation.

Alterations in glycosaminoglycan biosynthesis associated with the Ehlers-Danlos syndromes

Proteoglycans consist of a core protein substituted with one or more glycosaminoglycan (GAG) chains and execute versatile functions during many physiological and pathological processes. The biosynthesis of GAG chains is a complex process that depends on the concerted action of a variety of enzymes. Central to the biosynthesis of heparan sulfate (HS) and chondroitin sulfate/dermatan sulfate (CS/DS) GAG chains is the formation of a tetrasaccharide linker region followed by biosynthesis of HS or CS/DS-specific repeating disaccharide units, which then undergo modifications and epimerization. The importance of these biosynthetic enzymes is illustrated by several severe pleiotropic disorders that arise upon their deficiency. The Ehlers-Danlos syndromes (EDS) constitute a special group among these disorders. Although most EDS types are caused by defects in fibrillar types I, III, or V collagen, or their modifying enzymes, a few rare EDS types have recently been linked to defects in GAG biosynthesis. Spondylodysplastic EDS (spEDS) is caused by defective formation of the tetrasaccharide linker region, either due to β4GalT7 or β3GalT6 deficiency, whereas musculocontractural EDS (mcEDS) results from deficiency of D4ST1 or DS-epi1, impairing DS formation. This narrative review highlights the consequences of GAG deficiency in these specific EDS types, summarizes the associated phenotypic features and the molecular spectrum of reported pathogenic variants, and defines the current knowledge on the underlying pathophysiological mechanisms based on studies in patient-derived material, in vitro analyses, and animal models.

Acupuncture Interventions for Alzheimer’s Disease and Vascular Cognitive Disorders: A Review of Mechanisms

Cognitive impairment (CI) related to Alzheimer's disease (AD) and vascular cognitive disorders (VCDs) has become a key problem worldwide. Importantly, CI is a neuropsychiatric abnormality mainly characterized by learning and memory impairments. The hippocampus is an important brain region controlling learning and memory. Recent studies have highlighted the effects of acupuncture on memory deficits in AD and VCDs. By reviewing the literature published on this topic in the past five years, the present study intends to summarize the effects of acupuncture on memory impairment in AD and VCDs. Focusing on hippocampal synaptic plasticity, we reviewed the mechanisms underlying the effects of acupuncture on memory impairments through regulation of synaptic proteins, AD characteristic proteins, intestinal microbiota, neuroinflammation, microRNA expression, orexin system, energy metabolism, etc., suggesting that hippocampal synaptic plasticity may be the common as well as the core link underlying the above mechanisms. We also discussed the potential strategies to improve the effect of acupuncture. Additionally, the effects of acupuncture on synaptic plasticity through the regulation of vascular–glia–neuron unit were further discussed.

Sulfotransferase activity contributes to long-term potentiation and long-term memory

A critical role of protein modifications such as phosphorylation and acetylation in synaptic plasticity and memory is well documented. Tyrosine sulfation plays important roles in several biological processes. However, its role in synaptic plasticity and memory is not well understood. Here, we show that sulfation contributes to long-term potentiation (LTP) in the hippocampal slices. In addition, inhibition of sulfation impairs long-term memory in a spatial memory task without affecting acquisition or short-term memory. Furthermore, LTP-inducing stimulus enhances protein tyrosine sulfation. These results suggest an important role for tyrosine sulfation in LTP and memory.

Phosphatidylcholine restores neuronal plasticity of neural stem cells under inflammatory stress

The balances between NSCs growth and differentiation, and between glial and neuronal differentiation play a key role in brain regeneration after any pathological conditions. It is well known that the nervous tissue shows a poor recovery after injury due to the factors present in the wounded microenvironment, particularly inflammatory factors, that prevent neuronal differentiation. Thus, it is essential to generate a favourable condition for NSCs and conduct them to differentiate towards functional neurons. Here, we show that neuroinflammation has no effect on NSCs proliferation but induces an aberrant neuronal differentiation that gives rise to dystrophic, non-functional neurons. This is perhaps the initial step of brain failure associated to many neurological disorders. Interestingly, we demonstrate that phosphatidylcholine (PtdCho)-enriched media enhances neuronal differentiation even under inflammatory stress by modifying the commitment of post-mitotic cells. The pro-neurogenic effect of PtdCho increases the population of healthy normal neurons. In addition, we provide evidences that this phospholipid ameliorates the damage of neurons and, in consequence, modulates neuronal plasticity. These results contribute to our understanding of NSCs behaviour under inflammatory conditions, opening up new venues to improve neurogenic capacity in the brain.

Animal Models of Ehlers-Danlos Syndromes: Phenotype, Pathogenesis, and Translational Potential

The Ehlers-Danlos syndromes (EDS) are a group of heritable connective tissues disorders mainly characterized by skin hyperextensibility, joint hypermobility and generalized tissue fragility. Currently, 14 EDS subtypes each with particular phenotypic features are recognized and are caused by genetic defects in 20 different genes. All of these genes are involved in the biosynthesis and/or fibrillogenesis of collagens at some level. Although great progress has been made in elucidating the molecular basis of different EDS subtypes, the pathogenic mechanisms underlying the observed phenotypes remain poorly understood, and consequentially, adequate treatment and management options for these conditions remain scarce. To date, several animal models, mainly mice and zebrafish, have been described with defects in 14 of the 20 hitherto known EDS-associated genes. These models have been instrumental in discerning the functions and roles of the corresponding proteins during development, maturation and repair and in portraying their roles during collagen biosynthesis and/or fibrillogenesis, for some even before their contribution to an EDS phenotype was elucidated. Additionally, extensive phenotypical characterization of these models has shown that they largely phenocopy their human counterparts, with recapitulation of several clinical hallmarks of the corresponding EDS subtype, including dermatological, cardiovascular, musculoskeletal and ocular features, as well as biomechanical and ultrastructural similarities in tissues. In this narrative review, we provide a comprehensive overview of animal models manifesting phenotypes that mimic EDS with a focus on engineered mouse and zebrafish models, and their relevance in past and future EDS research. Additionally, we briefly discuss domestic animals with naturally occurring EDS phenotypes. Collectively, these animal models have only started to reveal glimpses into the pathophysiological aspects associated with EDS and will undoubtably continue to play critical roles in EDS research due to their tremendous potential for pinpointing (common) signaling pathways, unveiling possible therapeutic targets and providing opportunities for preclinical therapeutic interventions.

Chondroitin Sulfate/Dermatan Sulfate-Protein Interactions and Their Biological Functions in Human Diseases: Implications and Analytical Tools

Chondroitin sulfate (CS) and dermatan sulfate (DS) are linear anionic polysaccharides that are widely present on the cell surface and in the cell matrix and connective tissue. CS and DS chains are usually attached to core proteins and are present in the form of proteoglycans (PGs). They not only are important structural substances but also bind to a variety of cytokines, growth factors, cell surface receptors, adhesion molecules, enzymes and fibrillary glycoproteins to execute series of important biological functions. CS and DS exhibit variable sulfation patterns and different sequence arrangements, and their molecular weights also vary within a large range, increasing the structural complexity and diversity of CS/DS. The structure-function relationship of CS/DS PGs directly and indirectly involves them in a variety of physiological and pathological processes. Accumulating evidence suggests that CS/DS serves as an important cofactor for many cell behaviors. Understanding the molecular basis of these interactions helps to elucidate the occurrence and development of various diseases and the development of new therapeutic approaches. The present article reviews the physiological and pathological processes in which CS and DS participate through their interactions with different proteins. Moreover, classic and emerging glycosaminoglycan (GAG)-protein interaction analysis tools and their applications in CS/DS-protein characterization are also discussed.

Integrated Bioinformatics Analysis to Identify Alternative Therapeutic Targets for Alzheimer's Disease: Insights from a Synaptic Machinery Perspective

Alzheimer's disease (AD), the most common type of dementia, is a serious neurodegenerative disease that has no cure yet, but whose symptoms can be alleviated with available medications. Therefore, early and accurate diagnosis of the disease and elucidation of the molecular mechanisms involved in the progression of pathogenesis are critically important. This study aimed to identify dysregulated miRNAs and their target mRNAs through the integrated analysis of miRNA and mRNA expression profiling in AD patients versus unaffected controls. Expression profiles in postmortem brain samples from AD patients and healthy individuals were extracted from the Gene Expression Omnibus database and were analyzed using bioinformatics approaches to identify gene ontologies, pathways, and networks. Finally, the module analysis of the PPI network and hub gene selection was carried out. A total of five differentially expressed miRNAs were extracted from the miRNA dataset, and 4312 differentially expressed mRNAs were obtained from the mRNA dataset. By comparing the DEGs and the putative targets of the altered miRNAs, 116 (3 upregulated and 113 downregulated) coordinated genes were determined. Also, six hub genes (SNAP25, GRIN2A, GRIN2B, DLG2, ATP2B2, and SCN2A) were identified by constructing a PPI network. The results of the present study provide insight into mechanisms such as synaptic machinery and neuronal communication underlying AD pathogenesis, specifically concerning miRNAs.

Early-Life Stress Alters Synaptic Plasticity and mTOR Signaling: Correlation With Anxiety-Like and Cognition-Related Behavior

Early-life stress (ELS) predisposes individuals to psychiatric disorders, including anxiety and depression, and cognitive impairments later in life. However, the underlying molecular mechanisms are not completely understood. Developmental deficits in hippocampal synaptic plasticity are among the primary detrimental alterations in brain function induced by ELS. Impaired synaptic plasticity is usually accompanied by decreased synaptic proteins, such as postsynaptic density 95 (PSD95) and synaptophysin, which are important for synaptic function. The mTOR signaling pathway plays a vital role in regulating protein translation, and mTOR activation is functionally associated with synaptic protein synthesis. In the present study, we observed whether ELS impacts synaptic protein synthesis and mTOR signaling, which is involved in synaptic plasticity. Herein, we established a maternal separation (MS) and chronic restraint stress (CRS) model and evaluated anxiety-like behavior and cognitive function (e.g., learning and memory) in adulthood through behavioral examination and analyzed hippocampal expression levels of PSD95 and synaptophysin. To explore whether the mTOR signaling pathway was associated with ELS, we also examined the activity of mTOR and s6. The behavior tests indicated that maternally separated mice showed increased anxiety-like behavior and cognitive impairments. PSD95 and synaptophysin mRNA and protein expression levels were decreased in the hippocampus, and phosphorylated mTOR and phosphorylated s6 were significantly decreased in maternally separated mice vs. those not exposed to MS. Our data demonstrate that MS impairs synaptic plasticity and inhibits mTOR signaling, specifically via s6. Therefore, we speculate that ELS decreased synaptic plasticity via the inhibition of the mTOR pathway in the hippocampus, which may underlie vulnerability to stress and mental disorders in adulthood.

Acupuncture accelerates neural regeneration and synaptophysin production after neural stem cells transplantation in mice

BACKGROUND

Synaptophysin plays a key role in synaptic development and plasticity of neurons and is closely related to the cognitive process of Alzheimer’s disease (AD) patients. Exogenous neural stem cells (NSCs) improve the damaged nerve function. The effects of Sanjiao acupuncture on cognitive impairment may be related to the regulation of the NSC microenvironment.

AIM

To explore the anti-dementia mechanism of acupuncture by regulating the NSC microenvironment.

METHODS

NSCs were isolated from pregnant senescence-accelerated mouse resistant 1 (SAMR1) mice, labeled with BrdU, and injected into the hippocampus of senescence-accelerated mouse prone 8 (SAMP8) mice. Eight-month-old senescence-accelerated mice (SAM) were randomly divided into six groups: SAMR1 (RC), SAMP8 (PC), sham transplantation (PS), NSC transplantation (PT), NSC transplantation with acupuncture (PTA), and NSC transplantation with non-acupoint acupuncture (PTN). Morris water maze test was used to study the learning and memory ability of mice after NSC transplantation. Hematoxylin-eosin staining and immunofluorescence were used to observe the his-topathological changes and NSC proliferation in mice. A co-culture model of hippocampal slices and NSCs was established in vitro, and the synaptophysin expression in the hippocampal microenvironment of mice was observed by flow cytometry after acupuncture treatment.

RESULTS

Morris water maze test showed significant cognitive impairment of learning and memory in 8-mo-old SAMP8, which improved in all the NSC transplantation groups. The behavioral change in the PTA group was stronger than those in the other two groups (P < 0.05). Histopathologically, the hippocampal structure was clear, the cell arrangement was dense and orderly, and the necrosis of cells in CA1 and CA3 areas was significantly reduced in the PTA group when compared with the PC group. The BrdU-positive proliferating cells were found in NSC hippocampal transplantation groups, and the number increased significantly in the PTA group than in the PT and PTN groups (P < 0.05). Flow cytometry showed that after co-culture of NSCs with hippocampal slices in vitro, the synaptophysin expression in the PC group decreased in comparison to the RC group, that in PT, PTA, and PTN groups increased as compared to the PC group, and that in the PTA group increased significantly as compared to the PTN group with acupoint-related specificity (P < 0.05).

CONCLUSION

Acupuncture may promote nerve regeneration and synaptogenesis in SAMP8 mice by regulating the microenvironment of NSC transplantation to improve the nerve activity and promote the recovery of AD-damaged cells.

Backcrossing to an appropriate genetic background improves the birth rate of carbohydrate sulfotransferase 14 gene-deleted mice

Ehlers–Danlos syndromes (EDSs) are heterogeneous group of heritable connective tissue disorders characterized by joint and skin hyperextensibility as well as fragility of various organs. Recently, we described a new type of EDS, musculocontractual EDS (mcEDS-CHST14), caused by pathogenic variants of the carbohydrate sulfotransferase 14 (CHST14) gene mutation. B6;129S5-Chst14^tm1Lex/Mmucd (B6;129-Chst14 KO) mice are expected to be an animal model of mcEDS-CHST14. However, >90% of B6;129-Chst14 KO homozygous (B6;129-Chst14^−/−) mice show perinatal lethality. Therefore, improvement of the birth rate of Chst14^−/− mice is needed to clarify the pathophysiology of mcEDS-CHST14 using this animal model. Some B6;129-Chst14^−/− embryos had survived at embryonic day 18.5 in utero, suggesting that problems with delivery and/or childcare may cause perinatal lethality. However, in vitro fertilization and egg transfer did not improve the birth rate of the mice. A recent report showed that backcrossing to C57BL/6 strain induces perinatal death of all Chst14^−/− mice, suggesting that genetic background influences the birthrate of these mice. In the present study, we performed backcrossing of B6;129-Chst14 KO mice to a BALB/c strain, an inbred strain that shows lower risks of litter loss than C57BL/6 strain. Upon backcrossing 1 to 12 times, the birth rate of Chst14^−/− mice was improved with a birth rate of 6.12–18.64%. These results suggest that the genetic background influences the birth rate of Chst14^−/− mice. BALB/c congenic Chst14^−/− (BALB.Chst14^−/−) mice may facilitate investigation of mcEDS-CHST14. Furthermore, backcrossing to an appropriate strain may contribute to optimizing animal experiments.

Hypothalamic perineuronal net assembly is required for sustained diabetes remission induced by fibroblast growth factor 1 in rats

We recently showed that perineuronal nets (PNNs) enmesh glucoregulatory neurons in the arcuate nucleus (Arc) of the mediobasal hypothalamus (MBH)¹, but whether these PNNs play a role in either the pathogenesis of type 2 diabetes (T2D) or its treatment remains unclear. Here we show that PNN abundance within the Arc is markedly reduced in the Zucker diabetic fatty (ZDF) rat model of T2D, compared with normoglycaemic rats, correlating with altered PNN-associated sulfation patterns of chondroitin sulfate glycosaminoglycans in the MBH. Each of these PNN-associated changes is reversed following a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) at a dose that induces sustained diabetes remission in male ZDF rats. Combined with previous work localizing this FGF1 effect to the Arc area^2-4, our finding that enzymatic digestion of Arc PNNs markedly shortens the duration of diabetes remission following icv FGF1 injection in these animals identifies these extracellular matrix structures as previously unrecognized participants in the mechanism underlying diabetes remission induced by the central action of FGF1.

Proteoglycans as Therapeutic Targets in Brain Cancer

Proteoglycans (PGs) are heavily glycosylated diverse proteins consisting of a "core protein" covalently attached to glycosaminoglycans (GAGs) and present on the cell surface, extracellular matrix, and intracellular milieu. Extracellular proteoglycans play crucial roles in facilitating cell signaling and migration, interacting with growth factor receptors, intracellular enzymes, extracellular ligands, and matrix components, as well as structural proteins and promoting significant tumor-microenvironment interactions in cancerous settings. As a result of their highly regulated expression patterns, recent research has focused on the role of proteoglycans in the development of nervous tissue, such as their effect on neurite outgrowth, participation in the development of precursor cell types, and regulation of cell behaviors. The present review summarizes current progress for the studies of proteoglycan function in brain cancer and explains recent research involving brain glycoproteins as modulators of migration, cell adhesion, glial tumor invasion, and neurite outgrowth. Furthermore, we highlight the correlations between specific proteoglycan alterations and the suggested cancer-associated proteoglycans as novel biomarkers for therapeutic targets.

Cell-extrinsic requirement for sulfate in regulating hippocampal neurogenesis

Sulfate is a key anion required for a range of physiological functions within the brain. These include sulfonation of extracellular proteoglycans to facilitate local growth factor binding and to regulate the shape of morphogen gradients during development. We have previously shown that mice lacking one allele of the sulfate transporter Slc13a4 exhibit reduced sulfate transport into the brain, deficits in social behaviour, reduced performance in learning and memory tasks, and abnormal neurogenesis within the ventricular/subventricular zone lining the lateral ventricles. However, whether these mice have deficits in hippocampal neurogenesis was not addressed. Here, we demonstrate that adult Slc13a4+/- mice have increased neurogenesis within the subgranular zone (SGZ) of the hippocampal dentate gyrus, with elevated numbers of neural progenitor cells and intermediate progenitors. In contrast, by 12 months of age there were reduced numbers of neural stem cells in the SGZ of heterozygous mice. Importantly, we did not observe any changes in proliferation when we isolated and cultured progenitors in vitro in neurosphere assays, suggestive of a cell-extrinsic requirement for sulfate in regulating hippocampal neurogenesis. Collectively, these data demonstrate a requirement for sulfate transport during postnatal brain development to ensure normal adult hippocampal neurogenesis.

Gene biomarker discovery at different stages of Alzheimer using gene co-expression network approach

Alzheimer's disease (AD) is a chronic neurodegenerative disorder. It is the most common type of dementia that has remained as an incurable disease in the world, which destroys the brain cells irreversibly. In this study, a systems biology approach was adopted to discover novel micro-RNA and gene-based biomarkers of the diagnosis of Alzheimer's disease. The gene expression data from three AD stages (Normal, Mild Cognitive Impairment, and Alzheimer) were used to reconstruct co-expression networks. After preprocessing and normalization, Weighted Gene Co-Expression Network Analysis (WGCNA) was used on a total of 329 samples, including 145 samples of Alzheimer stage, 80 samples of Mild Cognitive Impairment (MCI) stage, and 104 samples of the Normal stage. Next, three gene-miRNA bipartite networks were reconstructed by comparing the changes in module groups. Then, the functional enrichment analyses of extracted genes of three bipartite networks and miRNAs were done, respectively. Finally, a detailed analysis of the authentic studies was performed to discuss the obtained biomarkers. The outcomes addressed proposed novel genes, including MBOAT1, ARMC7, RABL2B, HNRNPUL1, LAMTOR1, PLAGL2, CREBRF, LCOR, and MRI1and novel miRNAs comprising miR-615-3p, miR-4722-5p, miR-4768-3p, miR-1827, miR-940 and miR-30b-3p which were related to AD. These biomarkers were proposed to be related to AD for the first time and should be examined in future clinical studies.

Sevoflurane leads to learning and memory dysfunction via breaking the balance of tPA/PAI-1

Exposure to general anesthesia in early childhood may lead to adverse effects on adolescent neurocognition. This study investigated the effects of multiple inhalations of sevoflurane on long-term learning and memory in developing rats, and explored the mechanistic role of the tissue plasminogen activator (tPA)/plasminogen activator inhibitor-1 (PAI-1) fibrinolysis system and its regulatory relationship with the brain derived neurotrophic factor (BDNF) by activation of tropomysin related kinase B (TrkB). After rats were inhaled with sevoflurane for 2 h/d for three days, the expression levels of tPA, PAI-1, BDNF, its precursor(proBDNF), TrkB and phosphorylation of TrkB (p-TrkB) were detected at different time points. After 28 d, Morris water maze was used to examine learning and memory function; Golgi staining was used to investigate synaptic plasticity and synaptic-related proteins, such as Synapsin I(SYN1), growth associated protein 43(GAP-43), and postsynaptic density protein 95(PSD-95). Rats were given exogenous tPA and an inhibitor of PAI-1, TM5275. The results showed multiple inhalation of sevoflurane led to learning and memory dysfunction, downregulated the expression of the synaptic-related proteins, decreased dendritic spine density in the hippocampus, increased the expression level of proBDNF and PAI-1, and reduced expression of BDNF, tPA, and p-TrkB. Interestingly, tPA or TM5275 partially reversed the learning and memory dysfunction and the reduction of synaptic plasticity induced by sevoflurane exposure. Furthermore, they blocked the upregulation of proBDNF and PAI-1 protein expression and increased the expression of BDNF, tPA, and p-TrkB. The protective effect of tPA or TM5275 on rats following multiple sevoflurane inhalation was blocked by a TrkB inhibitor. Multiple inhalation of sevoflurane in rats inhibited the cleavage of proBDNF by disrupting the balance of the tPA/PAI-1 fibrinolysis system. This blocked the activation of the downstream TrkB signaling pathway and reduced hippocampal synaptic plasticity, leading to long-term learning and memory dysfunction. Therefore, Sevoflurane exposure could lead to learning and memory dysfunction by inhibiting BDNF cleavage via breaking the balance of tPA/PAI-1.

SRC-1 Knockout Exerts No Effect on Amyloid β Deposition in APP/PS1 Mice

Steroid receptor coactivator 1 (SRC-1) is the key coactivator because of its transcriptional activity. Previous studies have shown that SRC-1 is abundant in the hippocampus and has been implicated in cognition. SRC-1 is also related to some major risk factors for Alzheimer’s disease (AD), such as a decline in estrogen and aging, however, whether SRC-1 is involved in the pathogenesis of AD remains unclear. In this study, we established SRC-1 knockout in AD mice by cross breeding SRC-1^−/− mutant mice with APP/PS1 transgenic mice, and investigated the expression of some synaptic proteins, the amyloid β (Aβ) deposition, and activation of astrocytes and microglia in the hippocampus of APP/PS1×SRC-1^−/− mice. The results showed that SRC-1 knockout neither affects the Aβ plaque and activation of glia, nor changes the expression of synaptic proteins in AD model mice. The above results suggest that the complete deletion of SRC-1 in the embryo exerts no effect on the pathogenesis of APP/PS1 mice. Nevertheless, this study could not eliminate the possible role of SRC-1 in the development of AD due to the lack of observation of other events in AD such as tau hyperphosphorylation and the limitation of the animal model employed.

Upregulated proteoglycan-related signaling pathways in fluid flow shear stress-treated podocytes

The ultrafiltrate flow over the major processes and cell body generates fluid flow shear stress (FFSS) on podocytes. Hyperfiltration-associated increase in FFSS can lead to podocyte injury and detachment. Previously, we showed that FFSS-induced upregulation of the cyclooxygenase 2 (COX2)-PGE₂-prostaglandin E receptor 2 (EP2) axis in podocytes activates Akt-glycogen synthase kinase-3β-β-catenin and MAPK/ERK signaling in response to FFSS. Integrative MultiOmics Pathway Resolution (IMPRes) is a new bioinformatic tool that enables simultaneous time-series analysis of more than two groups to identify pathways and molecular connections. In the present study, we used previously characterized COX2 [prostaglandin-endoperoxide synthase 2 (Ptgs2)], EP2 (Ptger2), and β1-catenin (Ctnnb1) as "seed genes" from an array data set of four groups analyzed over a time course. The 3 seed genes shared 7 pathways and 50 genes of 14 pathways and 89 genes identified by IMPRes. A composite of signaling pathways highlighted the temporal molecular connections during mechanotransduction signaling in FFSS-treated podocytes. We investigated the "proteoglycans in cancer" and "galactose metabolism" pathways predicted by IMPRes. A custom-designed PCR array validated 60.7% of the genes predicted by IMPRes analysis, including genes for the above-named pathways. Further validation using Western blot analysis showed increased expression of phosho-Erbb2, phospho-mammalian target of rapamycin (mTOR), CD44, and hexokinase II (Hk2); decreased total Erbb2, galactose mutarotase (Galm), and β-1,4-galactosyltransferase 1 (B4galt1); and unchanged total mTOR and AKT3. These findings corroborate our previously reported results. This study demonstrates the potential of the IMPRes method to identify novel pathways. Identifying the "proteoglycans in cancer" and "galactose metabolism" pathways has generated a lead to study the significance of FFSS-induced glycocalyx remodeling and possible detachment of podocytes from the glomerular matrix.

TRIM32 Deficiency Impairs Synaptic Plasticity by Excitatory-Inhibitory Imbalance via Notch Pathway

Synaptic plasticity is the neural basis of physiological processes involved in learning and memory. Tripartite motif-containing 32 (TRIM32) has been found to play many important roles in the brain such as neural stem cell proliferation, neurogenesis, inhibition of nerve proliferation, and apoptosis. TRIM32 has been linked to several nervous system diseases including autism spectrum disorder, depression, anxiety, and Alzheimer's disease. However, the role of TRIM32 in regulating the mechanism of synaptic plasticity is still unknown. Our electrophysiological studies using hippocampal slices revealed that long-term potentiation of CA1 synapses was impaired in TRIM32 deficient (KO) mice. Further research found that dendritic spines density, AMPA receptors, and synaptic plasticity-related proteins were also reduced. NMDA receptors were upregulated whereas GABA receptors were downregulated in TRIM32 deficient mice, explaining the imbalance in excitatory and inhibitory neurotransmission. This caused overexcitation leading to decreased neuronal numbers in the hippocampus and cortex. In summary, this study provides this maiden evidence on the synaptic plasticity changes of TRIM32 deficiency in the brain and proposes that TRIM32 relates the notch signaling pathway and its related mechanisms contribute to this deficit.

Quercetin attenuates diabetic neuropathic pain by inhibiting mTOR/p70S6K pathway-mediated changes of synaptic morphology and synaptic protein levels in spinal dorsal horn of db/db mice

Numerous studies indicate that the changes of synaptic morphology and synaptic protein levels in spinal dorsal horn neurons contributes to the development and maintenance of neuropathic pain. Quercetin, a bioflavonoid compound, has been shown to have analgesic effect in several pain models. However, the underlying mechanism for quercetin to allieviate pain is unclear. Therefore, in this study, we observed the effect of quercetin on diabetic neuropathic pain in db/db mice and explored the underlying mechanisms. Our results showed that chronic quercetin treatment alleviated thermal hyperalgesia in db/db mice. Moreover, quercetin administration significantly reduced the total dendritic length, the number of dendritic branches, and the dendritic spine density in the spinal dorsal horn neurons of db/db mice. Meanwhile, the up-regulated expressions of synaptic plasticity-associated proteins postsynaptic density protein 95 (PSD-95) and synaptophysin in spinal dorsal horn of db/db mice were decreased by quercetin treatment. In addition, quercetin treatment reduced the phosphorylated levels of mammalian target of rapamycin (mTOR) and p70 ribosomal S6 kinase (p70S6K) in spinal dorsal horn of db/db mice. These results demonstrate that quercetin may alleviate diabetic neuropathic pain by inhibiting mTOR/p70S6K pathway-mediated changes of synaptic morphology and synaptic protein levels in spinal dorsal horn neurons of db/db mice. These findings suggest that quercetin may be a promising therapeutic drug in neuropathic pain.

Quantitative analysis of chondroitin sulfate disaccharides from human and rodent fixed brain tissue by electrospray ionization-tandem mass spectrometry

Chondroitin sulfates (CS) are long, negatively charged, unbranched glycosaminoglycan (GAG) chains attached to CS-proteoglycan (CSPG) core proteins that comprise the glycan component in both loose interstitial extracellular matrices (ECMs) and in rigid, structured perineuronal net (PNN) scaffolds within the brain. As aberrant CS-PNN formations have been linked to a range of pathological states, including Alzheimer's disease (AD) and schizophrenia, the analysis of CS-GAGs in brain tissue at the disaccharide level has great potential to enhance disease diagnosis and prognosis. Two mass-spectrometry (MS)-based approaches were adapted to detect CS disaccharides from minute fixed tissue samples with low picomolar sensitivity and high reproducibility. The first approach employed a straightforward, quantitative direct infusion (DI)-tandem mass spectrometry (MS/MS) technique to determine the percentages of Δ4S- and Δ6S-CS disaccharides within the 4S/6S-CS ratio, while the second used a comprehensive liquid chromatography (LC)-MS/MS technique to determine the relative percentages of Δ0S-, Δ4S-, Δ6S-, Δ4S6S-CS and Δ2S6S-CS disaccharides, with internal validation by full chondroitin lyase activity. The quantitative accuracy of the five primary biologically relevant CS disaccharides was validated using a developmental time course series in fixed rodent brain tissue. We then analyzed the CS disaccharide composition in formalin-fixed human brain tissue, thus providing the first quantitative report of CS sulfation patterns in the human brain. The ability to comprehensively analyze the CS disaccharide composition from fixed brain tissue provides a means with which to identify alterations in the CS-GAG composition in relation to the onset and/or progression of neurological diseases.