Changes In Neuronal Morphology Research Articles

Olfactory dysfunction as an early pathogenic indicator in C. elegans models of Alzheimer's and polyglutamine diseases.

Neurodegenerative diseases such as Alzheimer's disease and polyglutamine diseases are characterized by abnormal accumulation of misfolded proteins, leading to neuronal dysfunction and subsequent neuron death. However, there is a lack of studies that integrate molecular, morphological, and functional analyses in neurodegenerative models to fully characterize these time-dependent processes. In this study, we used C. elegans models expressing Aβ1-42 and polyglutamine to investigate early neuronal pathogenic features in olfactory neurons. Both models demonstrated significant reductions in odor sensitivity in AWB and AWC chemosensory neurons as early as day 1 of adulthood, while AWA chemosensory neurons showed no such decline, suggesting cell-type-specific early neuronal dysfunction. At the molecular level, Aβ1-42 or Q40 expression caused age-dependent protein aggregation and morphological changes in neurons. By day 6, both models displayed prominent protein aggregates in neuronal cell bodies and neurites. Notably, AWB neurons in both models showed significantly shortened cilia and increased instances of enlarged cilia as early as day 1 of adulthood. Furthermore, AWC neurons expressing Aβ1-42 displayed calcium signaling defects, with significantly reduced responses to odor stimuli on day 1, further supporting early behavioral dysfunction. In contrast, AWA neuron did not exhibit reduced calcium responses, consistent with the absence of detectable decreases in olfactory sensitivity in these neurons. These findings suggest that decreased calcium signaling and dysfunction in specific sensory neuron subtypes are early indicators of neurodegeneration in C. elegans, occurring prior to the formation of visible protein aggregates. We found that the ER unfolded protein response (UPR) is significantly activated in worms expressing Aβ1-42. Activation of the AMPK pathway alleviates olfactory defects and reduces fibrillar Aβ in these worms. This study underscores the use of C. elegans olfactory neurons as a model to elucidate mechanisms of proteostasis in neurodegenerative diseases and highlights the importance of integrated approaches.

Trillium tschonoskii rhizome saponin improves spatial learning and memory by enhancing neurovascular restorative in ischemic rats

BackgroundTrillium tschonoskii rhizome saponins (TSTT) has been significantly effective in treating traumatic injury, neurasthenia, cancer and inflammatory diseases as a folk medicine. However, the mechanism regarding to TSTT induced the neurovascular restorative after ischemia is without fully elucidated. PurposeThis research was constructed to study the value of TSTT in promoting endogenous repair of neurovascular and augmenting the ability of spatial study and memory retention in ischaemic rats. Study designThe improvement of TSTT on cerebral infraction and perfusion was observed by magnetic resonance imaging (MRI) experiments and the molecular mechanisms were further explored. MethodsFirst, rats were ligated the middle cerebral artery to construct a permanent ischaemia model, subsequently intragastric injection administrated with TSTT (120, 60, 30 mg kg-1) at 6 h after operation, then once a day during next 30 days. Morris water maze was applied to observe the neurobehavioral changes. Multimodal MRI sequences were performed to monitoring brain injuries as well as cerebral blood flow. Histopathological staining was employed to evaluate the morphological changes of neurons. Transmission electron microscopy (TEM) was employed to detect the neurons, vascular structure, and synapse. Immunofluorescent staining was utilized to evaluate the endogenous repair progress. The axonal growth-inhibitors and axonal guidance cues were analyzed using western blotting. ResultsContrast to the model group, TSTT declined the infarction and elevated the parenchymal volume. Notably, treated with TSTT significantly decreased the ADC (ipsilateral/contralateral). In histopathologic examination, TSTT prominently boosted amounts of cortical and striatal nerve cells and protected ultrastructure of neurovascular unit. According with results of nuclear magnetic imaging, TSTT enhanced endogenous repair progress. Especially, TSTT treatments obviously inhibited protein levels of NogoA/NgR/RhoA/ROCK2, accompanied by increased expression of Netrin/DCC and Slit2/Robo1. ConclusionTo sum up, our data illustrated that TSTT promoted cerebral reestablishment. The above result was in line with improving cerebral blood flow, elevated integrity of neurovascular structure, accelerating endogenous restoration and impairing the axonal growth inhibitors NogoA/NgR/RhoA/ROCK2 signaling, thereby improving poststroke learning and memory.

Highly selective sodium-glucose co-transporter type 2 inhibitor empagliflozin as means of brain protection in conditions of chronic brain dyscirculation

BACKGROUND: Chronic brain dyscirculation is one of the frequent type 2 diabetes mellitus (DM) complications and leads to patients’ disability. Sodium-glucose co-transporter type 2 inhibitors (SGLT-2i) have been proven to have advantages for cardiovascular system, but their effect on the central nervous system (CNS) has not been studied enough.AIM: To study empagliflozin effect on CNS damage functional and laboratory parameters in patients with type 2 DM and, under experimental conditions, to investigate the mechanisms of the drug neurotropic effect.MATERIALS AND METHODS: The clinical part of the study included patients with type 2 DM on metformin monotherapy (n=39). Patients with a target glycated hemoglobin level formed the “MET” group (n=19), in patients with a non-target glycated hemoglobin level empagliflozin was co-administered for the following 6 months (the “MET+EMPA” group, n=20). Healthy volunteers comprised the control group (n=16). The cognitive status and neuron-specific enolase (NSE) and neurofilament light chains (NLC) concentration were studied. DM was modeled in rats, thereafter the rats were treated with empagliflozin for 8 weeks. Microglia activation was assessed using anti-Iba-1 antibodies and morphological changes in neurons when stained by the Nissl method.RESULTS: Both in the “MET+EMPA” and the “MET” groups cognitive deficits were observed, according to the Montreal Cognitive Assessment (MOCA) (24.0 (23.0; 27.0) and 25.0 (21.0; 27.0) points) and the Mini-Mental State Examination (MMSE) (23.75 (23.0; 27.0) and 25.0 (21.0; 27.0) points). Empagliflozin therapy led to the cognitive status normalization after 6 months (26.5 (24.0; 27.0) points according to the MOCA scale and 27.5 (24.0; 28.0) points according to the MMSE). Initially, all patients had a significant increase of NSE (3.60 (2.66; 3.76) ng/ml in the “MET” group, 3.22 (2.94; 3.54) ng/ml in the “MET+EMPA» group, 2.72 (2.13; 2.72) ng/ml in the «Control» group) and NLC (4.50 (3.31; 5.56) ng/ml in the «MET» group, 5, 25 (3.75; 6.25) ng/ml in the «MET+EMPA» group comparing with 3.50 (2.25; 3.50) ng/ml in the «Control» group). Empagliflozin therapy led to a significant decrease in NLC already after 3 months (3.80 (3.25; 3.87) ng/ml), without significant influence on the NSE level. In the experiment, DM was characterized by an increased number of activated microgliocytes and destructured neurons and a decreased number of neurons with a normal structure. Empagliflozin therapy was accompanied by a decrease in the number of immunopositive microgliocytes in the CA1 zone of the hippocampus and an increase in the number of structured neurons.CONCLUSION: Type 2 diabetes mellitus is characterized by functional and biochemical changes in the central nervous system even under satisfactory glycemic control. Therapy with empagliflozin has a neuroprotective effect, manifested in an improvement in cognitive status and a decrease in NLC level. Empagliflozin reduces neuronal damage and abnormal microglial activation.

Neonatal Cannabidiol Exposure Impairs Spatial Memory and Disrupts Neuronal Dendritic Morphology in Young Adult Rats.

Introduction: Early life is a sensitive period for brain development. Perinatal exposure to cannabis is increasingly linked to disruption of neurodevelopment; however, research on the effects of cannabidiol (CBD) on the developing brain is scarce. In this study, we aim to study the developmental effects of neonatal CBD exposure on behavior and dendritic architecture in young adult rats. Materials and Methods: Male and female neonatal Sprague Dawley rats were treated with CBD (50 mg/kg) intraperitoneally on postnatal day (PND) 1, 3, and 5 and evaluated for behavioral and neuronal morphological changes during early adulthood. Rats were subjected to a series of behavioral tasks to evaluate long-term effects of neonatal CBD exposure, including the Barnes maze, open field, and elevated plus maze paradigms to assess spatial memory and anxiety-like behavior. Following behavioral evaluation, animals were sacrificed, and neuronal morphology of the cortex and hippocampus was assessed using Golgi-Cox (GC) staining. Results: Rats treated with CBD displayed a sexually dimorphic response in spatial memory, with CBD-treated females developing a deficit but not males. CBD did not elicit alterations in anxiety-like behavior in either sex. Neonatal CBD caused an overall decrease in dendritic length and spine density (apical and basal) in cortical and hippocampal neurons in both sexes. Sholl analysis also revealed a decrease in dendritic intersections in the cortex and hippocampus, indicating reduced dendritic arborization. Conclusions: This study provides evidence that neonatal CBD exposure perturbs normal brain development and leads to lasting alterations in spatial memory and neuronal dendrite morphology in early adulthood, with sex-dependent sensitivity.

Elucidating the molecular symphony: unweaving the transcriptional & epigenetic pathways underlying neuroplasticity in opioid dependence and withdrawal.

The persistent use of opioids leads to profound changes in neuroplasticity of the brain, contributing to the emergence and persistence of addiction. However, chronic opioid use disrupts the delicate balance of the reward system in the brain, leading to neuroadaptations that underlie addiction. Chronic cocaine usage leads to synchronized alterations in gene expression, causing modifications in the Nucleus Accumbens (NAc), a vital part of the reward system of the brain. These modifications assist in the development of maladaptive behaviors that resemble addiction. Neuroplasticity in the context of addiction involves changes in synaptic connectivity, neuronal morphology, and molecular signaling pathways. Drug-evoked neuroplasticity in opioid addiction and withdrawal represents a complicated interaction between environmental, genetic, and epigenetic factors. Identifying specific transcriptional and epigenetic targets that can be modulated to restore normal neuroplasticity without disrupting essential physiological processes is a critical consideration. The discussion in this article focuses on the transcriptional aspects of drug-evoked neuroplasticity, emphasizing the role of key transcription factors, including cAMP response element-binding protein (CREB), ΔFosB, NF-kB, Myocyte-enhancing factor 2 (MEF2), Methyl-CpG binding protein 2 (MeCP2), E2F3a, and FOXO3a. These factors regulate gene expression and lead to the neuroadaptive changes observed in addiction and withdrawal. Epigenetic regulation, which involves modifying gene accessibility by controlling these structures, has been identified as a critical component of addiction development. By unraveling these complex molecular processes, this study provides valuable insights that may pave the way for future therapeutic interventions targeting the mechanisms underlying addiction and withdrawal.

Fibrin-Polycaprolactone Scaffolds for the Differentiation of Human Neural Progenitor Cells into Dopaminergic Neurons.

Parkinson's disease (PD), a progressive central nervous system disorder marked by involuntary movements, poses a significant challenge in neurodegenerative research due to the gradual degeneration of dopaminergic (DA) neurons. Early diagnosis and understanding of PD's pathogenesis could slow disease progression and improve patient management. In vitro modeling with DA neurons derived from human-induced pluripotent stem cell-derived neural progenitor cells (NPCs) offers a promising approach. These neurons can be cultured on electrospun (ES) nanofibrous polycaprolactone (PCL) scaffolds, but PCL's hydrophobic nature limits cell adhesion. We investigated the ability of ES PCL scaffolds coated with hydrophilic extracellular matrix-based biomaterials, including cell basement membrane proteins, Matrigel, and Fibrin, to enhance NPC differentiation into DA neurons. We hypothesized that fibrin-coated scaffolds would maximize differentiation based on fibrin's known benefits in neuronal tissue engineering. The scaffolds both coated and uncoated were characterized using scanning electron microscopy (SEM), transmission electron microscopy, Fourier transform infrared spectroscopy-attenuated total reflectance, and dynamic mechanical analysis to assess their properties. NPCs were seeded on the coated scaffolds, differentiated, and matured into DA neurons. Immunocytochemistry targeting tyrosine hydroxylase (TH) and SEM confirmed DA neuronal differentiation and morphological changes. Electrophysiology via microelectrode array recorded their neuronal firing. Results showed enhanced neurite extension, increased TH expression, and active electrical activity in cells on fibrin-coated scaffolds. Diluted fibrin coatings particularly promoted more pronounced neuronal differentiation and maturation. This study introduces a novel tissue-on-a-chip platform for neurodegenerative disease research using DA neurons.

The DNA repair protein DNA-PKcs modulates synaptic plasticity via PSD-95 phosphorylation and stability

The key DNA repair enzyme DNA-PKcs has several and important cellular functions. Loss of DNA-PKcs activity in mice has revealed essential roles in immune and nervous systems. In humans, DNA-PKcs is a critical factor for brain development and function since mutation of the prkdc gene causes severe neurological deficits such as microcephaly and seizures, predicting yet unknown roles of DNA-PKcs in neurons. Here we show that DNA-PKcs modulates synaptic plasticity. We demonstrate that DNA-PKcs localizes at synapses and phosphorylates PSD-95 at newly identified residues controlling PSD-95 protein stability. DNA-PKcs −/− mice are characterized by impaired Long-Term Potentiation (LTP), changes in neuronal morphology, and reduced levels of postsynaptic proteins. A PSD-95 mutant that is constitutively phosphorylated rescues LTP impairment when over-expressed in DNA-PKcs −/− mice. Our study identifies an emergent physiological function of DNA-PKcs in regulating neuronal plasticity, beyond genome stability.

Communicating pain: emerging axonal signaling in peripheral neuropathic pain.

Peripheral nerve damage often leads to the onset of neuropathic pain (NeuP). This condition afflicts millions of people, significantly burdening healthcare systems and putting strain on families' financial well-being. Here, we will focus on the role of peripheral sensory neurons, specifically the Dorsal Root Ganglia neurons (DRG neurons) in the development of NeuP. After axotomy, DRG neurons activate regenerative signals of axons-soma communication to promote a gene program that activates an axonal branching and elongation processes. The results of a neuronal morphological cytoskeleton change are not always associated with functional recovery. Moreover, any axonal miss-targeting may contribute to NeuP development. In this review, we will explore the epidemiology of NeuP and its molecular causes at the level of the peripheral nervous system and the target organs, with major focus on the neuronal cross-talk between intrinsic and extrinsic factors. Specifically, we will describe how failures in the neuronal regenerative program can exacerbate NeuP.

Morphofunctional changes in brain and peripheral blood in aged Wistar rats due to AlCl3 exposure

The purpose of the study: To examine morphofunctional changes of brain and peripheral blood in aged Wistar rats to observe adaptive reactions as a response on AlCl3 exposure. Methods: The work was performed on male Wistar rats, 24 months of age. Animals consumed a solution of AlCl3 100 mg/kg per day for 60 days. Morphological changes of neurons and microglia, mRNA expression levels of pro- and anti-inflammatory cytokines, microglia activation markers, amyloid-related and hypoxia-related proteins, as well as monocyte and lymphocyte subpopulations in peripheral blood, were examined. Results: AlCl3-treated old rats showed the increasing of hyperchromic neurons in 2 out of 3 examined regions of the hippocampus; morphological features of microglia cells’ dystrophy; the upregulation of pro-inflammatory cytokine Il-18 and the downregulation of anti-inflammatory cytokine Il-10, as well as App, Bace1, and Hif-1a; the decreasing of percentage of B-cells, general CD3+ lymphocyte population, including CD4+ T-helpers and CD8+ cytotoxic cells, but the increasing of CD4+/CD8+ ratio in peripheral blood. Conclusion: AlCl3-treated aged rats demonstrated systemic maladaptation to AlCl3 impact. Unlike adult rodents, aged ones have the background of inflammaging, as well as elderly people. The exposure of AlCl3 could potentially be a replacement of integral cellular and molecular processes accompanying age-related diseases, presenting in most elderly people, as an enhancer of inflammaging and hypoxia. These conditions make this model of neurodegeneration a reliable one to explore the initial mechanisms of such detrimental process, as well as prove aged rats more suitable subjects to perform future researches in this field.

PIEZO1 as a new target for hyperglycemic stress-induced neuropathic injury: The potential therapeutic role of bezafibrate

Hyperglycemic stress can directly lead to neuronal damage. The mechanosensitive ion channel PIEZO1 can be activated in response to hyperglycemia, but its role in hyperglycemic neurotoxicity is unclear. The role of PIEZO1 in hyperglycemic neurotoxicity was explored by constructing a hyperglycemic mouse model and a high-glucose HT22 cell model. The results showed that PIEZO1 was significantly upregulated in response to high glucose stress. In vitro experiments have shown that high glucose stress induces changes in neuronal cell morphology and membrane tension, a key mechanism for PIEZO1 activation. In addition, high glucose stress upregulates serum/glucocorticoid-regulated kinase-1 (SGK1) and activates PIEZO1 through the Ca2+ pool and store-operated calcium entry (SOCE). PIEZO1-mediated Ca2+ influx further enhances SGK1 and SOCE, inducing intracellular Ca2+ peaks in neurons. PIEZO1 mediated intracellular Ca2+ elevation leads to calcium/calmodulin-dependent protein kinase 2α (CaMK2α) overactivation, which promotes oxidative stress and apoptosis signalling through p-CaMK2α/ERK/CREB and ox-CaMK2α/MAPK p38/NFκB p65 pathways, subsequently inducing synaptic damage and cognitive impairment in mice. The intron miR-107 of pantothenic kinase 1 (PANK1) is highly expressed in the brain and has been found to target PIEZO1 and SGK1. The PANK1 receptor is activated by peroxisome proliferator-activated receptor α (PPARα), an activator known to upregulate miR-107 levels in the brain. The clinically used lipid-lowering drug bezafibrate, a known PPARα activator, may upregulate miR-107 through the PPARɑ/PANK1 pathway, thereby inhibiting PIEZO1 and improving hyperglycemia-induced neuronal cell damage. This study provides a new idea for the pathogenesis and drug treatment of hyperglycemic neurotoxicity and diabetes-related cognitive dysfunction.

The mutated cytoplasmic fragile X messenger ribonucleoprotein 1 (FMR1)-interacting protein 2 (CYFIP2 S968F) regulates cocaine-induced reward behaviour and plasticity in the nucleus accumbens.

Cytoplasmic fragile X messenger ribonucleoprotein 1 (FMR1)-interacting protein 2 (CYFIP2), as a component of the Wiskott-Aldrich syndrome protein family verprolin-homologous protein (WAVE) regulatory complex, is involved in actin polymerization, contributing to neuronal development and structural plasticity. Mutating serine-968 to phenylalanine (S968F) in CYFIP2 causes an altered cocaine response in mice. The neuronal mechanisms underlying this response remain unknown. We performed cocaine reward-related behavioural tests and examined changes in synaptic protein phenotypes and neuronal morphology in the nucleus accumbens (NAc), using CYFIP2 S968F knock-in mice to investigate the role of CYFIP2 in regulating cocaine reward. CYFIP2 S968F mutation attenuated cocaine-induced behavioural sensitization and conditioned place preference. Cocaine-induced c-Fos was not observed in the NAc of CYFIP2 S968F knock-in mice. However, c-Fos induction was still evident in the medial prefrontal cortex (mPFC). CYFIP2 S968F mutation altered cocaine-associated CYFIP2 signalling, glutamatergic protein expression and synaptic density in the NAc following cocaine exposure. To further determine the role of CYFIP2 in NAc neuronal activity and the mPFC projecting to the NAc activity-mediating reward response, we used optogenetic tools to stimulate the NAc or mPFC-NAc pathway and observed that optogenetic activation of the NAc or mPFC-NAc pathway induced reward-related behaviours. This effect was not observed in the S968F mutation in CYFIP2. These results suggest that CYFIP2 plays a role in controlling cocaine-mediated neuronal function and structural plasticity in the NAc, and that CYFIP2 could serve as a target for regulating cocaine reward.

Hippocampal transcriptomic analyses reveal the potential antiapoptotic mechanism of a novel anticonvulsant agent Q808 on pentylenetetrazol-induced epilepsy in rats

Brain apoptosis is one of the main causes of epileptogenesis. The antiapoptotic effect and potential mechanism of Q808, an innovative anticonvulsant chemical, have never been reported. In this study, the seizure stage and latency to reach stage 2 of pentylenetetrazol (PTZ) seizure rat model treated with Q808 were investigated. The morphological change and neuronal apoptosis in the hippocampus were detected by hematoxylin and eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, respectively. The hippocampal transcriptomic changes were observed using RNA sequencing (RNA-seq). The expression levels of hub genes were verified by quantitative reverse-transcription PCR (qRT-PCR). Results revealed that Q808 could allay the seizure score and prolong the stage 2 latency in seizure rats. The morphological changes of neurons and the number of apoptotic cells in the DG area were diminished by Q808 treatment. RNA-seq analysis revealed eight hub genes, including Map2k3, Nfs1, Chchd4, Hdac6, Siglec5, Slc35d3, Entpd1, and LOC103690108, and nine hub pathways among the control, PTZ, and Q808 groups. Hub gene Nfs1 was involved in the hub pathway sulfur relay system, and Map2k3 was involved in the eight remaining hub pathways, including Amyotrophic lateral sclerosis, Cellular senescence, Fc epsilon RI signaling pathway, GnRH signaling pathway, Influenza A, Rap1 signaling pathway, TNF signaling pathway, and Toll-like receptor signaling pathway. qRT-PCR confirmed that the mRNA levels of these hub genes were consistent with the RNA-seq results. Our findings might contribute to further studies exploring the new apoptosis mechanism and actions of Q808.

Autism risk gene Cul3 alters neuronal morphology via caspase-3 activity in mouse hippocampal neurons.

Autism Spectrum Disorders (ASDs) are neurodevelopmental disorders (NDDs) in which children display differences in social interaction/communication and repetitive stereotyped behaviors along with variable associated features. Cul3, a gene linked to ASD, encodes CUL3 (CULLIN-3), a protein that serves as a key component of a ubiquitin ligase complex with unclear function in neurons. Cul3 homozygous deletion in mice is embryonic lethal; thus, we examine the role of Cul3 deletion in early synapse development and neuronal morphology in hippocampal primary neuronal cultures. Homozygous deletion of Cul3 significantly decreased dendritic complexity and dendritic length, as well as axon formation. Synaptic spine density significantly increased, mainly in thin and stubby spines along with decreased average spine volume in Cul3 knockouts. Both heterozygous and homozygous knockout of Cul3 caused significant reductions in the density and colocalization of gephyrin/vGAT puncta, providing evidence of decreased inhibitory synapse number, while excitatory synaptic puncta vGulT1/PSD95 density remained unchanged. Based on previous studies implicating elevated caspase-3 after Cul3 deletion, we demonstrated increased caspase-3 in our neuronal cultures and decreased neuronal cell viability. We then examined the efficacy of the caspase-3 inhibitor Z-DEVD-FMK to rescue the decrease in neuronal cell viability, demonstrating reversal of the cell viability phenotype with caspase-3 inhibition. Studies have also implicated caspase-3 in neuronal morphological changes. We found that caspase-3 inhibition largely reversed the dendrite, axon, and spine morphological changes along with the inhibitory synaptic puncta changes. Overall, these data provide additional evidence that Cul3 regulates the formation or maintenance of cell morphology, GABAergic synaptic puncta, and neuronal viability in developing hippocampal neurons in culture.

Morphometric Changes of the Myenteric Plexus in the Colon of the Mice-D-Galactose Ageing Model

Ageing-related diseases are paramount for understanding the socioeconomic impact of the postmodern society. Neuronal degeneration is a known phenomenon in ageing. The D-galactose model of accelerated ageing is widely used in age-associated neuronal cell death because of the oxidative stress it induces, which correlates to reduced cognitive performance and robustly detectable neuronal shrinkage in the CNS. This study aims at demonstrating the morphological changes of neurons of the myenteric plexus in mice treated with D-galactose. D-galactose was given orally with drinking water, resulting in an average dose of 500 mg/kg daily for six weeks. In the D-galactose accelerated ageing model, a significant size reduction of the neuronal perikarya of the myenteric plexus was observed all along the large intestine. The average soma area at the caecum in the control group was 305 µm2, which was reduced by almost 20% in the ageing model. In contrast, at the level of the proximal colon in the D-galactose ageing model, the average area of the neuronal soma was 280 µm2, a reduction of 30%. The most significant reduction has been observed at the level of the distal colon, where the neuronal soma was reduced by 40%. There is a significant reduction of the area of the neuronal bodies in the myenteric plexus among different parts of the mice's large intestine in the accelerated ageing model. It can be inferred that D-galactose-induced morphological changes in the myenteric plexus may be related to the increased gastrointestinal motility dysfunction with ageing.

Evolutionary and developmental specialization of foveal cell types in the marmoset

In primates, high-acuity vision is mediated by the fovea, a small specialized central region of the retina. The fovea, unique to the anthropoid lineage among mammals, undergoes notable neuronal morphological changes during postnatal maturation. However, the extent of cellular similarity across anthropoid foveas and the molecular underpinnings of foveal maturation remain unclear. Here, we used high-throughput single-cell RNA sequencing to profile retinal cells of the common marmoset (Callithrix jacchus), an early divergent in anthropoid evolution from humans, apes, and macaques. We generated atlases of the marmoset fovea and peripheral retina for both neonates and adults. Our comparative analysis revealed that marmosets share almost all their foveal types with both humans and macaques, highlighting a conserved cellular structure among primate foveas. Furthermore, by tracing the developmental trajectory of cell types in the foveal and peripheral retina, we found distinct maturation paths for each. In-depth analysis of gene expression differences demonstrated that cone photoreceptors and Müller glia (MG), among others, show the greatest molecular divergence between these two regions. Utilizing single-cell ATAC-seq and gene-regulatory network inference, we uncovered distinct transcriptional regulations differentiating foveal cones from their peripheral counterparts. Further analysis of predicted ligand-receptor interactions suggested a potential role for MG in supporting the maturation of foveal cones. Together, these results provide valuable insights into foveal development, structure, and evolution.

Inhibition of endoplasmic reticulum stress attenuates morphine protracted abstinence-induced anxiety-like behaviors in the male mice

The anxiety caused by morphine protracted abstinence is considered to be an important factor contributes to drug-seeking and relapse. Endoplasmic reticulum (ER) stress plays important roles in many kinds of mental disorders including drug addiction and anxiety, but it is unclear whether ER stress is involved in anxiety-like behaviors induced by morphine withdrawal. In this study, by using behavioral test, western blot, immunofluorescence, electron transmission microscope, we found that: (1) Inhibition of endoplasmic reticulum stress by 4-Phenylbutyric acid (4-PBA) could attenuate anxiety-like behaviors induced by morphine withdrawal. (2) The endoplasmic reticulum stress-related proteins in the lateral habenula (LHb) but not in the nucleus accumbens (NAc), ventral pallidum (VP), basolateral amygdala (BLA) and CA1 of hippocampus was upregulated by morphine withdrawal, upregulation of endoplasmic reticulum stress-related proteins in the lateral habenula induced by morphine withdrawal was inhibited by 4-PBA. (3) Endoplasmic reticulum stress-related protein CHOP and eIF2α were expressed in neurons but not in microglia in the LHb. (4) Morphine withdrawal induced neuronal morphological change in the LHb, which was attenuated by 4-PBA.

Autism Spectrum Disorder- and/or Intellectual Disability-Associated Semaphorin-5A Exploits the Mechanism by Which Dock5 Signalosome Molecules Control Cell Shape.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that includes autism, Asperger's syndrome, and pervasive developmental disorder. Individuals with ASD may exhibit difficulties in social interactions, communication challenges, repetitive behaviors, and restricted interests. While genetic mutations in individuals with ASD can either activate or inactivate the activities of the gene product, impacting neuronal morphogenesis and causing symptoms, the underlying mechanism remains to be fully established. Herein, for the first time, we report that genetically conserved Rac1 guanine-nucleotide exchange factor (GEF) Dock5 signalosome molecules control process elongation in the N1E-115 cell line, a model line capable of achieving neuronal morphological changes. The increased elongation phenotypes observed in ASD and intellectual disability (ID)-associated Semaphorin-5A (Sema5A) Arg676-to-Cys [p.R676C] were also mediated by Dock5 signalosome molecules. Indeed, knockdown of Dock5 using clustered regularly interspaced short palindromic repeat (CRISPR)/CasRx-based guide(g)RNA specifically recovered the mutated Sema5A-induced increase in process elongation in cells. Knockdown of Elmo2, an adaptor molecule of Dock5, also exhibited similar recovery. Comparable results were obtained when transfecting the interaction region of Dock5 with Elmo2. The activation of c-Jun N-terminal kinase (JNK), one of the primary signal transduction molecules underlying process elongation, was ameliorated by either their knockdown or transfection. These results suggest that the Dock5 signalosome comprises abnormal signaling involved in the process elongation induced by ASD- and ID-associated Sema5A. These molecules could be added to the list of potential therapeutic target molecules for abnormal neuronal morphogenesis in ASD at the molecular and cellular levels.

Role of estrogen in sex differences in memory, emotion and neuropsychiatric disorders.

Estrogen regulates a wide range of neuronal functions in the brain, such as dendritic spine formation, remodeling of synaptic plasticity, cognition, neurotransmission, and neurodevelopment. Estrogen interacts with intracellular estrogen receptors (ERs) and membrane-bound ERs to produce its effect via genomic and non-genomic pathways. Any alterations in these pathways affect the number, size, and shape of dendritic spines in neurons associated with psychiatric diseases. Increasing evidence suggests that estrogen fluctuation causes changes in dendritic spine density, morphology, and synapse numbers of excitatory and inhibitory neurons differently in males and females. In this review, we discuss the role of estrogen hormone in rodents and humans based on sex differences. First, we explain estrogen role in learning and memory and show that a high estrogen level alleviates the deficits in learning and memory. Secondly, we point out that estrogen produces a striking difference in emotional memories in men and women, which leads them to display sex-specific differences in underlying neuronal signaling. Lastly, we discuss that fluctuations in estrogen levels in men and women are related to neuropsychiatric disorders, including schizophrenia, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), bipolar disorder (BPD), major depressive disorder (MDD), substance use disorder (SUD), and anxiety disorders.

Study on the chemical constituents and mechanism of Kai-Xin-San based on UPLC-Q-Exactive MS and network pharmacology

Ethnopharmacological relevanceVascular disease (VD) is a kind of common disease harmful to the health of the middle-aged and elderly, which has the characteristics of long treatment cycle and high recurrence rate, and without effective method to treat so far. Traditional Chinese medicine (TCM) has the characteristics of multi-components and multi-targets to treat diseases. Kai-Xin-San is a TCM formula applied for treating psychiatric diseases such as depression in China for thousands of years, and it has been used in clinical treatment of VD. But up to now, its active composition and mechanism are not clear. Aim of the studyTo explore the effective components of Kai-Xin-San, investigate the effect of Kai-Xin-San on angiogenesis, screen and verify the related targets and possible mechanisms of Kai-Xin-San against VD. Materials and methodsUPLC-Q-Exactive Orbitrap MS was performed to identify the chemical components of Kai-Xin-San. The mechanism of multi-components, multi-targets, and multi-pathways of Kai-Xin-San in the treatment of VD were explored by network pharmacology. And then, quail chick chorioallantoic membrane (qCAM) assays were used to evaluate the vascular protective activity of Kai-Xin-San. Evaluation of angiogenesis by calculating the relative vessels area. The levels of VEGFA and Akt1 in qCAM were measured by RT-PCR. Twenty-five male SD rats were randomly divided into the sham group, model group, Donepezil (0.45 mg/kg) group, Kai-Xin-San low dose group (0.1575 g/kg), Kai-Xin-San high dose group (0.63 g/kg). Two-vessel occlusion (2-VO) rat model is established to evaluate the therapeutic effect of Kai-Xin-San pretreatment. Hematoxylin-eosin (HE) staining is conducted to detect the morphological changes of neurons in the hippocampus. ResultsData showed that 62 compounds were identified in Kai-Xin-San. The network pharmacology results showed 73 compounds in Kai-Xin-San play a role in the treatment of VD, such as Ginsenoside Rh4, kaempferol, and Poricoic acid C. A total of 7 main targets are predicted, including Akt1, TNF and so on. Kai-Xin-San could increase VEGFA and Akt1 expression, promote angiogenesis and regulate the PI3K-Akt signaling pathway. The results depict that Kai-Xin-San has dose-dependently improved the cognitive function in 2-VO model rats. It has also been showed that Kai-Xin-San can rescue neuron damage in the hippocampus. ConclusionThe complex chemical components of Kai-Xin-San play a synergistic role in the treatment of VD, and involve multiple pathways and targets. To protect blood vessels by promoting angiogenesis is one of the potential mechanisms of Kai-Xin-San in the treatment of VD. This study reveals that Kai-Xin-San protects the 2-VO model rats from ischemic injury by alleviating neuron damage in the hippocampus.

Scutellaria Baicalensis Georgi Stem and Leaf Flavonoids Ameliorate the Learning and Memory Impairment in Rats Induced by Okadaic Acid.

The objective of this study is to explore the impact and underlying mechanism of Scutellaria baicalensis Georgi stem and leaf flavonoids (SSFs) on cognitive impairment caused by intracerebroventricular injection of okadaic acid (OA) in rats. An experimental model of Alzheimer's disease (AD) was induced in rats by intracerebroventricular injection of OA, resulting in memory impairment. The Morris water maze test was employed to confirm the successful establishment of the memory impairment model. The rats that exhibited significant memory impairment were randomly divided into different groups, including a model group, three SSFs dose groups (25, 50, and 100 mg/kg), and a positive control group treated with Ginkgo biloba tablets (GLT) at a dose of 200 mg/kg. To evaluate the learning and memory abilities of the rats, the Morris water maze test was conducted. Hematoxylin-eosin (HE) staining was used to observe any morphological changes in neurons. Immunohistochemistry (IHC) was performed to measure the expression of choline acetyltransferase (ChAT) protein. Western blotting (WB) was utilized to assess the phosphorylation levels of tau protein at Ser262 and Ser396. The activities of inducible nitric oxide synthase (iNOS) and constitutive nitric oxide synthase (cNOS) were quantified using ultraviolet spectrophotometry. The levels of inflammatory factors, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), were measured using ELISA. In rats, the administration of OA via intracerebroventricular injection resulted in cognitive impairment, neuropathological changes, and alterations in protein expression and activity levels. Specifically, the protein expression of ChAT was significantly reduced (P<0.01), while the phosphorylation levels of tau protein at Ser262 and Ser396 were significantly increased (P<0.01). Moreover, iNOS activity in the hippocampus and cerebral cortex exhibited a significant increase (P<0.01), whereas cNOS activity showed a decrease (P<0.05). Furthermore, the levels of IL-1β and TNF-α in the cerebral cortex were elevated (P<0.01), while the level of IL-6 was decreased (P<0.05). The administration of three doses of SSFs and GLT to rats exhibited varying degrees of improvement in the aforementioned pathological alterations induced by OA. SSFs demonstrated the ability to enhance cognitive function and mitigate memory deficits in rats following intracerebroventricular injection of OA. This beneficial effect may be attributed to the modulation of ChAT protein expression, tau hyperphosphorylation, NOS activity, and inflammatory cytokine levels by SSFs.