Overlapping role of synaptophysin and synaptogyrin family proteins in determining the small size of synaptic vesicles.

Members of the synaptophysin and synaptogyrin family are vesicle proteins with four transmembrane domains. In spite of their abundance in synaptic vesicle (SV) membranes, their role remains elusive and only mild defects at the cellular and organismal level are observed in mice lacking one or more family members. Here, we show that coexpression with synapsin in fibroblasts of each of the four brain-enriched members of this family-synaptophysin, synaptoporin, synaptogyrin 1, and synaptogyrin 3-is sufficient to generate clusters of small vesicles in the same size range of SVs. Moreover, mice lacking all these four proteins have larger SVs. We conclude that synaptophysin and synaptogyrin family proteins play an overlapping function in the biogenesis of SVs and in determining their small size.

Synaptophysin chaperones the assembly of 12 SNAREpins under each ready-release vesicle.

The synaptic vesicle protein Synaptophysin (Syp) has long been known to form a complex with the Vesicle associated soluble N-ethylmaleimide sensitive fusion protein attachment receptor (v-SNARE) Vesicle associated membrane protein (VAMP), but a more specific molecular function or mechanism of action in exocytosis has been lacking because gene knockouts have minimal effects. Utilizing fully defined reconstitution and single-molecule measurements, we now report that Syp functions as a chaperone that determines the number of SNAREpins assembling between a ready-release vesicle and its target membrane bilayer. Specifically, Syp directs the assembly of 12 ± 1 SNAREpins under each docked vesicle, even in the face of an excess of SNARE proteins. The SNAREpins assemble in successive waves of 6 ± 1 and 5 ± 2 SNAREpins, respectively, tightly linked to oligomerization of and binding to the vesicle Ca++ sensor Synaptotagmin. Templating of 12 SNAREpins by Syp is likely the direct result of its hexamer structure and its binding of VAMP2 dimers, both of which we demonstrate in detergent extracts and lipid bilayers.

BOK-engaged mitophagy alleviates neuropathology in Alzheimer's disease.

Mitochondrial malfunction associated with impaired mitochondrial quality control and self-renewal machinery, known as mitophagy, is an under-appreciated mechanism precipitating synaptic loss and cognitive impairments in Alzheimer's disease (AD). Promoting mitophagy has been shown to improve cognitive function in AD animals. However, the regulatory mechanism was unclear, which formed the aim of this study. Here, we found that a neuron-specific loss of Bcl-2 family member BOK in AD patients and APPswe/PS1dE9 (APP/PS1) mice is closely associated with mitochondrial damage and mitophagy defects. We further revealed that BOK is the key to the Parkin-mediated mitophagy through competitive binding to the MCL1/Parkin complex, resulting in Parkin release and translocation to damaged mitochondria to initiate mitophagy. Furthermore, overexpressing bok in hippocampal neurons of APP/PS1 mice alleviated mitophagy and mitochondrial malfunction, resulting in improved cognitive function. Conversely, the knockdown of bok worsened the aforementioned AD-related changes. Our findings uncover a novel mechanism of BOK signaling through regulating Parkin-mediated mitophagy to mitigate amyloid pathology, mitochondrial and synaptic malfunctions, and cognitive decline in AD, thus representing a promising therapeutic target.

Dissection of the long-range projections of specific neurons at the synaptic level in the whole mouse brain.

Through synaptic connections, long-range circuits transmit information among neurons and connect different brain regions to form functional motifs and execute specific functions. Tracing the synaptic distribution of specific neurons requires submicron-level resolution information. However, it is a great challenge to map the synaptic terminals completely because these fine structures span multiple regions, even in the whole brain. Here, we develop a pipeline including viral tracing, sample embedding, fluorescent micro-optical sectional tomography, and big data processing. We mapped the whole-brain distribution and architecture of long projections of the parvalbumin neurons in the basal forebrain at the synaptic level. These neurons send massive projections to multiple downstream regions with subregional preference. With three-dimensional reconstruction in the targeted areas, we found that synaptic degeneration was inconsistent with the accumulation of amyloid-ß plaques but was preferred in memory-related circuits, such as hippocampal formation and thalamus, but not in most hypothalamic nuclei in 8-month-old mice with five familial Alzheimer's disease mutations. Our pipeline provides a platform for generating a whole-brain atlas of cell-type-specific synaptic terminals in the physiological and pathological brain, which can provide an important resource for the study of the organizational logic of specific neural circuits and the circuitry changes in pathological conditions.

Comprehensive mapping of synaptic vesicle protein 2A (SV2A) in health and neurodegenerative diseases: a comparative analysis with synaptophysin and ground truth for PET-imaging interpretation.

Synaptic dysfunction and loss are central to neurodegenerative diseases and correlate with cognitive decline. Synaptic Vesicle Protein 2A (SV2A) is a promising PET-imaging target for assessing synaptic density in vivo, but comprehensive mapping in the human brain is needed to validate its biomarker potential. This study used quantitative immunohistochemistry and Western blotting to map SV2A and synaptophysin (SYP) densities across six cortical regions in healthy controls and patients with early-onset Alzheimer's disease (EOAD), late-onset Alzheimer's disease (LOAD), progressive supranuclear palsy (PSP), and frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-GRN). We identified region in SV2A density among controls and observed disease- and region-specific reductions, with the most severe in FTLD-GRN (up to 59.5%) and EOAD. EOAD showed a 49% reduction in the middle frontal gyrus (MFG), while LOAD had over 30% declines in the inferior frontal gyrus (IFG) and hippocampus (CA1). In PSP, smaller but significant reductions were noted in the hippocampal formation, with the inferior temporal gyrus (ITG) relatively unaffected. A strong positive correlation between SV2A and SYP densities confirmed SV2A's reliability as a synaptic integrity marker. This study supports the use of SV2A PET imaging for early diagnosis and monitoring of neurodegenerative diseases, providing essential data for interpreting in vivo PET results. Further research should explore SV2A as a therapeutic target and validate these findings in larger, longitudinal studies.

Indoxyl sulphate-TNFα axis mediates uremic encephalopathy in rodent acute kidney injury.

Acute kidney injury (AKI) is often accompanied by uremic encephalopathy resulting from accumulation of uremic toxins in brain possibly due to impaired blood-brain barrier (BBB) function. Anionic uremic toxins are substrates or inhibitors of organic anionic transporters (OATs). In this study we investigated the CNS behaviors and expression/function of BBB OAT3 in AKI rats and mice, which received intraperitoneal injection of cisplatin 8 and 20 mg/kg, respectively. We showed that cisplatin treatment significantly inhibited the expressions of OAT3, synaptophysin and microtubule-associated protein 2 (MAP2), impaired locomotor and exploration activities, and increased accumulation of uremic toxins in the brain of AKI rats and mice. In vitro studies showed that uremic toxins neither alter OAT3 expression in human cerebral microvascular endothelial cells, nor synaptophysin and MAP2 expressions in human neuroblastoma (SH-SY5Y) cells. In contrast, tumour necrosis factor alpha (TNFα) and the conditioned medium (CM) from RAW264.7 cells treated with indoxyl sulfate (IS) significantly impaired OAT3 expression. TNFα and CM from IS-treated BV-2 cells also inhibited synaptophysin and MAP2 expressions in SH-SY5Y cells. The alterations caused by TNFα and CMs in vitro, and by AKI and TNFα in vivo were abolished by infliximab, a monoclonal antibody designed to intercept and neutralize TNFα, suggesting that AKI impaired the expressions of OAT3, synaptophysin and MAP2 in the brain via IS-induced TNFα release from macrophages or microglia (termed as IS-TNFα axis). Treatment of mice with TNFα (0.5 mg·kg-1·d-1, i.p. for 3 days) significantly increased p-p65 expression and reduced the expressions of Nrf2 and HO-1. Inhibiting NF-κB pathway, silencing p65, or activating Nrf2 and HO-1 obviously attenuated TNFα-induced downregulation of OAT3, synaptophysin and MAP2 expressions. Significantly increased p-p65 and decreased Nrf2 and HO-1 protein levels were also detected in brain of AKI mice and rats. We conclude that AKI inhibits the expressions of OAT3, synaptophysin and MAP2 due to IS-induced TNFα release from macrophages or microglia. TNFα impairs the expressions of OAT3, synaptophysin and MAP2 partly via activating NF-κB pathway and inhibiting Nrf2-HO-1 pathway.

The potential neuroprotective effects of Spirulina platensis in a valproic acid-induced experimental model of autism in the siblings of albino rats: targeting PIk3/AKT/mTOR signalling pathway.

Introduction: Autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders with poor social interaction, communication issues, aberrant motor movements, and limited repetitive interests and behaviour. Spirulina platensis (SP) contains several multi-nutrients and has a wide range of neuroprotective properties.Aim: The target of the current experiment is to detect the protective effects of S. platensis on valproic-induced autism in adult female albino rats' siblings for the first time.Materials and Methods: Twelve Pregnant rats were separated into four main groups; Group I (control); Group II (S. platensis); Group III (autistic group); and Group IV (autistic SP-treated group). Fifteen offspring pups from each group were sacrificed, brain was divided for biochemical analysis as superoxide dismutase and malondialdehyde were evaluated spectrophotometrically while interleukin-6, interleukin-12, Bcl-2-associated X protein, B-cell lymphoma-2, Beclin-1, brain-derived neurotrophic factor were assessed by ELISA, other division of brain were used for gene expression of PI3k, Akt and mTOR pathway, last division of brain were stained using (H&E) and Giemsa stains. Tumour necrosis factor alpha (TNF-α) and Synaptophysin (SYN) markers were used for immunohistochemical staining.Results: Autistic Group (III) showed an increment in levels of MDA, IL-6, IL12 and BAX while showing a decrement in SOD, Bcl-2 and Beclin-1 as well as increased PI3k, Akt and mTOR gene expression. Autistic Group (III) also exhibited hypocellularity and disorganization of hippocampal and prefrontal cortex cells. The autistic SP-treated group (IV) showed improvement in these biochemical markers and pathological changes. Our findings suggest that Spirulina platensis will be significant in managing autism.

Insulinoma-associated protein 1 (INSM1) immunohistochemical expression in normal, hyperplastic, and neoplastic canine neuroendocrine tissues.

Insulinoma-associated protein 1 (INSM1), a recently identified neuroendocrine marker, is a transcriptional regulator with highly conserved INSM1 homologues in various species. This study investigated the immunohistochemical reactivity of the INSM1 antibody in 20 normal canine neuroendocrine tissues from various anatomical locations, 87 hyperplastic or neoplastic tissues of neuroendocrine origin, and 62 non-neuroendocrine neoplasms and compared the results with those of chromogranin A and synaptophysin in neuroendocrine neoplasms. Western blot was performed on fresh canine pituitary glands and canine parathyroid glands to confirm the specificity of the anti-INSM1 antibody. The results showed that the anti-INSM1 antibody could detect nuclear expression in normal canine neuroendocrine tissues, except for the parathyroid glands. INSM1 was detectable in 79/87 (91%) of the hyperplastic and neoplastic neuroendocrine lesions, but all parathyroid carcinomas and parathyroid adenomas (three samples each) were negative for INSM1. In contrast, INSM1 was detected in only one of 62 (2%) non-neuroendocrine neoplasms. The overall percentage of neuroendocrine neoplasms that immunolabeled positively for all three markers was 89%. In addition, the nuclear expression of INSM1 was easier to interpret than that of chromogranin A or synaptophysin. These findings confirm that INSM1 is a useful immunohistochemical marker for diagnosing canine neuroendocrine neoplasms, except for parathyroid neoplasms, and should be considered as part of immunohistochemistry panels to improve diagnostic capability.

Epigenetic alternations in the SYP and DLG4 genes due to low-level methylmercury exposure during neuronal differentiation in vitro.

Methylmercury (MeHg) is an environmental toxin known to damage the central nervous system. When pregnant women ingest seafood, which may contain accumulated MeHg, fetal development may be affected. The embryonic period, a time of major epigenetic change, is susceptible to epigenetic disruptions due to chemical exposure. Therefore, understanding the molecular mechanism underlying MeHg's effects on neuronal development requires consideration of epigenetic factors. In this study, we investigated epigenetic modifications in the synaptophysin (SYP) and discs large MAGUK scaffold protein 4 (DLG4) genes. LUHMES cells were exposed to 1 nM MeHg for 6 days during days 2-8 of neural differentiation. MeHg exposure significantly reduced the number of spikes observed on day 16 of differentiation. Both mRNA and protein expression levels of SYP and DLG4 were significantly decreased by MeHg exposure. Additionally, MeHg treatment reduced acetyl histone H3 levels associated with transcriptional activity in the SYP gene while increasing histone H3 lysine 27 tri-methylation (H3K27me3) levels related to transcriptional repression. Conversely, regarding the DLG4 gene, MeHg exposure increased H3K27me3 levels. Differential changes in DNA methylation (high and low methylation states) were observed in the SYP and DLG4 genes due to MeHg exposure depending on CpG site position. In conclusion, this study suggests that epigenetic changes, particularly histone modifications, contribute to decreased MeHg exposure-induced SYP and DLG4 expression during neuronal differentiation.

Composite haemangioendothelioma with neuroendocrine marker differentiation presenting as a pink-brown nodule.

We report a case of a 55-year-old female with an asymptomatic pink-brown nodule. Histological examination demonstrated a composite haemangioendothelioma with positive synaptophysin staining.

Whole-Body Vibration Affects Hippocampal Choline Acetyltransferase and Synaptophysin Expression and Improves Spatial Memory in Young Adult Mice.

BACKGROUND: Beneficial effects of whole-body vibration (WBV) on brain and musculoskeletal health in mice have been demonstrated, but underlying mechanisms remain relatively unrevealed. WBV improves attention and memory performance in mice, putatively through stimulation of the cholinergic system. Here, we investigated the effects of WBV on the septo-hippocampal cholinergic system. METHODS: Young C57BL/6 mice (8 weeks old) were subjected to 10 min WBV/day (mechanical vibration: 30 Hz; ~0.1-µm peak-to-peak displacement), 5X/week for 5 weeks. In Experiment 1, choline acetyltransferase (ChAT)-immunoreactivity in the septum and hippocampus was analyzed either 2 or 24 h after the last WBV session. Pseudo-WBV-treated mice (same handling procedure as WBV, but no vibrations) served as controls. In Experiment 2, the longitudinal profile of ChAT-immunoreactivity was analyzed in the hippocampus after 1, 2, 3, 4, or 5 weeks of WBV. In addition, synaptophysin immunostaining was performed at either 2 and 5 weeks of WBV. Mice housed 1/cage during the entire experiment served as controls. The balance-beam test was used to monitor the functional impact of WBV. In Experiment 3, a Y-maze reference-memory test was performed after 5 weeks of WBV to obtain a functional cognitive outcome measure of WBV. Pseudo-WBV treated mice served as controls. RESULTS: In Experiment 1, ChAT-immunoreactivity was significantly enhanced after the last WBV session of the 5-week period. This was found in the septum, Cornu Ammonis 1 (CA1), CA3, and dentate gyrus, and was dependent on layer and time-point (2 or 24 h). Experiment 2 revealed that, ChAT-immunoreactivity was lower after 2 weeks of WBV, whereas it was significantly higher after 5 weeks (similar to in Experiment 1). Immunostaining for synaptophysin, a marker for synaptic density, was also significantly higher after 5 weeks of WBV, but not significantly lower after 2 weeks, as was ChAT. WBV-treated groups performed significantly better than did controls on the balance beam from week 3 onwards. Experiment 3 showed that WBV-treated mice had better spatial-reference memory performance in the Y-maze test than did pseudo-WBV controls. CONCLUSIONS: Our results indicate that WBV stimulates the septo-hippocampal cholinergic system in a gradual and dynamic way that may contribute to improved spatial-memory performance. This finding suggests that WBV, by upregulation of the septo-hippocampal cholinergic system, may be considered a valuable therapeutic strategy to enhance brain functions in aging, neurodegenerative, and other brain diseases.

Clinicopathologic features and diagnostic challenges of small cluster pattern appendiceal neuroendocrine tumors.

Appendiceal neuroendocrine neoplasms (NENs) can present with various growth patterns including the traditional triad of histologic patterns-insular, trabecular and tubular. A small cluster pattern was also found in this study and the literature on this specific morphology is limited. In this study, we conducted a comprehensive review of appendiceal NENs from our institution over a ten-year period. Clinical and demographic data were obtained from medical records. Immunohistochemical stains were performed with antibodies specific for synaptophysin, chromogranin, INSM1, CD56, serotonin and peptide YY. The small cluster pattern was found in 29.4 % of all cases evaluated. The tumor cells in these cases were predominantly located at the distal tip of the appendix, associated with fibrous obliteration. These tumors were smaller in size and tended towards less advanced tumor stage, with reduced incidence of lymphovascular and/or perineural invasion. Chromogranin expression was identified in 76 % of these cases. There is a heterogeneous hormone profile with 46.7 % serotonin and 33.3 % peptide YY. In conclusion, the small cluster pattern NENs present with unique histological features and hormone expression profile. Among the various neuroendocrine markers, INSM1 showed superior diagnostic performance, with high sensitivity and minimal non-specific staining.

Olfactory neuroblastoma: A rare sinonasal malignancy.

Olfactory neuroblastoma is a rare malignant tumour arising from the olfactory nerve and extending into the nasal cavity. In this case report, the case of a 42-year-old male is presented. The patient had a two-month history of progressive nasal blockage and episodes of epistaxis. No complaint of anosmia or facial pain was reported. All the necessary examinations were performed. Upon investigation, the CT scan and MRI showed a polypoid mass involving the right maxillary sinus, eroding the medial wall and expanding into the osteo-meatal complex. The diagnosis of olfactory neuroblastoma was confirmed through histopathological examination and further validated by immunohistochemistry as it was positive for synaptophysin, chromogranin, gamma enolase, and neurofilament. On staging, the tumour was Kadish B. The mass was excised by lateral rhinotomy. The patient was kept on radiotherapy and was free from recurrence upon follow-up 10 months later. It was concluded that based on the analysis of findings related to olfactory neuroblastomas, clinicians should contemplate the possibility of an ONB when radiographic images depict a dumbbell-shaped mass within the nasal cavity, accompanied by peritumoural cysts. Using a multimodal treatment approach is advisable.

Clinical, pathologic, and molecular features of amphicrine prostate cancer.

BACKGROUND: Amphicrine prostate carcinoma (AMPC) is a poorly defined subset of prostate cancer in which cells co-express luminal prostate epithelial and neuroendocrine markers. The optimal treatment strategy is unknown. We sought to further characterize the clinical, histomorphologic, and molecular characteristics of AMPC and to identify areas of potential future treatment investigations. METHODS: We retrospectively identified 17 cases of AMPC at a single institution, defined as synaptophysin expression in >70% of cells and co-expression of androgen receptor (AR) signaling markers (either AR, PSA, or NKX3.1) in >50% of cells. Clinical and histologic features of AMPC cases as well as response to treatment and clinical outcomes were described. RESULTS: Five AMPC cases arose de novo in the absence of prior systemic treatment and behaved distinctly from cases that were treatment-emergent. In these de novo cases, despite expression of neuroendocrine markers, prognosis appeared more favorable than high-grade neuroendocrine carcinoma, with two (40%) patients with de novo metastatic disease, universal response to androgen deprivation therapy, and no deaths at a median follow-up of 12.3 months. Treatment-emergent AMPC arose a median of 41.1 months after androgen deprivation therapy initiation and was associated with poor response to therapy. CONCLUSIONS: We show that amphicrine prostate cancer is a unique entity and differs in clinical and molecular features from high-grade neuroendocrine carcinomas of the prostate. Our study highlights the need to recognize AMPC as a unique molecularly defined subgroup of prostate cancer.

Intrahippocampal injection of IL-1ß upregulates Siah1-mediated degradation of synaptophysin by activation of the ERK signaling in male rat.

Interleukin-1ß (IL-1ß) has been described to exert important effect on synapses in the brain. Here, we explored if the synapses in the hippocampus would be adversely affected following intracerebral IL-1ß injection and, if so, to clarify the underlying molecular mechanisms. Adult male Sprague-Dawley rats were divided into control, IL-1ß, IL-1ß + PD98059, and IL-1ß + MG132 groups and then sacrificed for detection of synaptophysin (syn) protein level, synaptosome glutamate release, and synapse ultrastructure by western blotting, glutamate kit and electron microscopy, respectively. These rats were tested by Morris water maze for learning and memory ability. It was determined by western blotting whether IL-1ß exerted the effect of on syn and siah1 expression in primary neurons via extracellular regulated protein kinases (ERK) signaling pathway. Intrahippocampal injection of IL-1ß in male rats and sacrificed at 8d resulted in a significant decrease in syn protein, damage of synapse structure, and abnormal release of neurotransmitters glutamate. ERK inhibitor and proteosome inhibitor treatment reversed the above changes induced by IL-1ß both in vivo and in vitro. In primary cultured neurons incubated with IL-1ß, the expression level of synaptophysin was significantly downregulated coupled with abnormal glutamate release. Furthermore, use of PD98059 had confirmed that ERK signaling pathway was implicated in synaptic disorders caused by IL-1ß treatment. The present results suggest that exogenous IL-1ß can suppress syn protein level and glutamate release. A possible mechanism for this is that IL-1ß induces syn degradation that is regulated by the E3 ligase siah1 via the ERK signaling pathway.

Mitochondrial impairment and synaptic dysfunction are associated with neurological defects in iPSCs-derived cortical neurons of MERRF patients.

BACKGROUND: Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome is a rare inherited mitochondrial disease mainly caused by the m.8344A > G mutation in mitochondrial tRNALys gene, and usually manifested as complex neurological disorders and muscle weakness. Currently, the pathogenic mechanism of this disease has not yet been resolved, and there is no effective therapy for MERRF syndrome. In this study, MERRF patients-derived iPSCs were used to model patient-specific neurons for investigation of the pathogenic mechanism of neurological disorders in mitochondrial disease. METHODS: MERRF patient-derived iPSCs were differentiated into excitatory glutamatergic neurons to unravel the effects of the m.8344A > G mutation on mitochondrial bioenergetic function, neural-lineage differentiation and neuronal function. By the well-established differentiation protocol and electrophysiological activity assay platform, we examined the pathophysiological behaviors in cortical neurons of MERRF patients. RESULTS: We have successfully established the iPSCs-derived neural progenitor cells and cortical-like neurons of patients with MERRF syndrome that retained the heteroplasmy of the m.8344A > G mutation from the patients' skin fibroblasts and exhibited the phenotype of the mitochondrial disease. MERRF neural cells harboring the m.8344A > G mutation exhibited impaired mitochondrial bioenergetic function, elevated ROS levels and imbalanced expression of antioxidant enzymes. Our findings indicate that neural immaturity and synaptic protein loss led to the impairment of neuronal activity and plasticity in MERRF neurons harboring the m.8344A > G mutation. By electrophysiological recordings, we monitored the in vivo neuronal behaviors of MERRF neurons and found that neurons harboring a high level of the m.8344A > G mutation exhibited impairment of the spontaneous and evoked potential-stimulated neuronal activities. CONCLUSIONS: We demonstrated for the first time the link of mitochondrial impairment and synaptic dysfunction to neurological defects through impeding synaptic plasticity in excitatory neurons derived from iPSCs of MERRF patients harboring the m.8344A > G mutation. This study has provided new insight into the pathogenic mechanism of the tRNALys gene mutation of mtDNA, which is useful for the development of a patient-specific iPSCs platform for disease modeling and screening of new drugs to treat patients with MERRF syndrome.

Synaptogenesis by Cholinergic Stimulation of Astrocytes.

Astrocytes release numerous factors known to contribute to the process of synaptogenesis, yet knowledge about the signals that control their release is limited. We hypothesized that neuron-derived signals stimulate astrocytes, which respond to neurons through the modulation of astrocyte-released synaptogenic factors. Here we investigate the effect of cholinergic stimulation of astrocytes on synaptogenesis in co-cultured neurons. Using a culture system where primary rat astrocytes and primary rat neurons are first grown separately allowed us to independently manipulate astrocyte cholinergic signaling. Subsequent co-culture of pre-stimulated astrocytes with naïve neurons enabled us to assess how prior stimulation of astrocyte acetylcholine receptors uniquely modulates neuronal synapse formation. Pre-treatment of astrocytes with the acetylcholine receptor agonist carbachol increased the expression of synaptic proteins, the number of pre- and postsynaptic puncta, and the number of functional synapses in hippocampal neurons after 24 h in co-culture. Astrocyte secretion of the synaptogenic protein thrombospondin-1 increased after cholinergic stimulation and inhibition of the receptor for thrombospondins prevented the increase in neuronal synaptic structures. Thus, we identified a novel mechanism of neuron-astrocyte-neuron communication, where neuronal release of acetylcholine stimulates astrocytes to release synaptogenic proteins leading to increased synaptogenesis in neurons. This study provides new insights into the role of neurotransmitter receptors in developing astrocytes and into our understanding of the modulation of astrocyte-induced synaptogenesis.

Preparation of pumpkin oil-based nanoemulsion as a potential estrogen replacement therapy to alleviate neural-immune interactions in an experimental postmenopausal model.

As estrogen production decreases during menopause; the brain's metabolism tends to stall and become less effective. Estrogen most likely protects against neurodegeneration. Consequently, a comprehensive study of the benefits of hormone replacement therapy as a neuroprotective effect is urgently required. This study was designed to fabricate pumpkin seed oil nanoparticles (PSO) in nanoemulsion form (PSO-NE) and investigate their potential role in attenuating the neural-immune interactions in an experimental postmenopausal model.Sixty female white albino rats were divided into six groups: control, sham, ovariectomized (OVX), and three OVX groups treated with 17ß-estradiol, PSO, and PSO-NE respectively. Transmission Electron Microscopy (TEM), and particle size analyzer were performed for nanoemulsion evaluation. Serum levels of estrogen, brain amyloid precursor protein (APP), serum levels of nuclear factor kappa B (NF-κß), interleukin 6 (IL-6), transthyretin (TTR), and synaptophysin (SYP) were evaluated. The expression of estrogen receptors (ER-α, ß) in the brain tissue was estimated. The findings revealed that the approached PSO-NE system was able to reduce the interfacial tension, enhance the dispersion entropy, lower the system free energy to an extremely small value, and augment the interfacial area. PSO-NE, showed a significant increase in the levels of estrogen, brain APP, SYP, and TTR accompanied with a significant increased in the expression of brain ER-α, ß compared to the OVX group. In conclusion, the phytoestrogen content of PSO exhibited a significant prophylactic effect on neuro-inflammatory interactions, ameliorating both estrogen levels and the inflammatory cascades.

Celastrus paniculatus oil ameliorates NF-KB mediated neuroinflammation and synaptic plasticity in the scopolamine-induced cognitive impairment rat model.

BACKGROUND AND AIM: Traditionally, Celastrus paniculatus Willd. (CP) oil has been utilized as a tranquilizer and memory enhancer. The present study investigated the neuropharmacological activity and efficacy of CP oil in ameliorating scopolamine-induced cognitive impairment in rats. EXPERIMENTAL PROCEDURE: Cognitive deficiency was induced in rats by administration of scopolamine (2 mg/kg intraperitoneal injection) for a period of 15 days. Donepezil served as a reference drug and CP oil was tested as both preventive and curative treatments. Animals' behaviour was assessed through the Morris water maze (MWM), novel object preference (NOR), and conditioned avoidance (CA) tests. Oxidative stress parameters, bioamine concentration (dopamine, noradrenaline, and 5-hydroxytryptamine), nerve growth factor (NGF), interleukin-6 (IL-6), nuclear factor kappa B (NF-кB), and tumor necrosis factor-alpha (TNFα) were estimated. Synaptophysin immunohistochemistry was performed. RESULTS: Our results showed that CP oil ameliorated behavioural deficits. It reduced latency to find a hidden platform in MWM. Reduced novel object exploration time and discrimination index (p < 0.05) in the NOR. Reduced step-down latency and normalized conditioned avoidance response (p < 0.001) in the CA test. CP oil increased dopamine, serotonin, norepinephrine, superoxide dismutase (SOD), glutathione, and catalase levels. It decreased malondialdehyde (MDA), acetylcholinesterase activity, IL-6, NF-кB (P < 0.001), TNFα, and NGF levels. Treatment showed approximate typical reactivity to synaptophysin. CONCLUSION: Our data is suggestive that CP oil treatment improves behavioural test outcomes, increases biogenic amine concentration, and decreases acetylcholinesterase activity, and neuroinflammatory biomarkers. It also restores synaptic plasticity. It thus improves cognitive functions against scopolamine-induced amnesia in rats by improving cholinergic function.

Neuroprotective effects of vitamin B1 on memory impairment and suppression of pro-inflammatory cytokines in traumatic brain injury.

Traumatic Brain Injury (TBI) remains one of the prevailing disorders that affect millions of people around the globe. There is a cascade of secondary attributes attached to TBI including excitotoxicity, axonal degeneration, neuroinflammation, oxidative stress, and apoptosis. Neuroinflammation is caused due to the activation of microglia along with pro-inflammatory cytokines. The activation of microglia triggers TNF-α which sequentially results in the triggering and upregulation of NF-kB. The aim of the current research was to investigate vitamin B1's potential as neuroprotective agent against TBI-induced neuroinflammation arbitrated memory impairment together with pre- and post-synaptic dysfunction in an adult albino male mice model. TBI was induced using the weight-drop method which caused the microglial activation resulting in neuroinflammation along with synaptic dysfunction leading to the memory impairment of the adult mice. Vitamin B1 was administered for seven days via the intraperitoneal pathway. To analyze the memory impairment and efficacy of vitamin B1, Morris water maze and Y-maze tests were performed. The escape latency time and short-term memories of the experimental mice treated with vitamin B1 were significantly different from the reference mice. The western blot results showed that vitamin B1 has reduced neuroinflammation by downregulating proinflammatory cytokines (NFκ-B, TNF- α). Vitamin B1 also proved its worthiness as a convincing neuroprotective agent by reducing memory dysfunction and recovering the activities of pre- and post-synapse via upregulation of synaptophysin and Postsynaptic density protein 95 (PSD-95).