Polysialylated Neural Cell Adhesion Molecule Research Articles

Supplementation of 3'-Sialyllactose During the Growth Period Improves Learning and Memory Development in Mice.

3'-Sialyllactose (3'-SL), a major acidic oligosaccharide found in human milk, has been investigated to improve cognitive-enhancing effects with 3 weeks old C57BL/6 mice by administering 3'-SL orally at a dose of 350 mg/kg/day for 6 weeks. Behavioral tests indicated that supplementation with 3'-SL promoted cognitive and memory development in young mice. Through interaction network and coenrichment analysis, nine differentially expressed genes (DEGs) related to memory and cognition were identified and localized in the hippocampal tissue of mice. The intervention of 3'-SL significantly increased the metabolism of sialic acid in mouse hippocampal tissue and promoted the expression of learning-related genes (p < 0.05). Notably, it increased the expression of genes associated with neural cell adhesion molecule (NCAM, p < 0.05), glutamate receptors, and fibroblast growth factor receptor (FGFR, p < 0.05). This suggests that 3'-SL may elevate polysialylated NCAM (PSA-NCAM) levels, which could subsequently interact with FGFR and glutamate receptors, thereby enhancing synaptic growth and plasticity. Additionally, 3'-SL altered the composition of the mouse intestinal microbiota. The synergistic action of gut microbiota and intestinal sialidase promoted the production of free sialic acid, providing essential nutritional elements for the development of the brain's nervous system. In conclusion, our findings provide new insights into the promoting effect of 3'-SL on cognitive development in growing mice and elucidate its molecular mechanisms.

NCAM and attached polysialic acid affect behaviors of breast epithelial cells through differential signaling pathways.

Neural cell adhesion molecule (NCAM), a common mammalian cell surface glycoprotein, is the major substrate of polysialic acid (polySia). Polysialylated NCAM occurs in many types of cancer, but rarely in normal adult tissues. The functional role of NCAM hypersialylation in the epithelial-mesenchymal transition (EMT) process remains unclear. The present study indicates that NCAM and attached polysialic acid affect behaviors of breast epithelial cells through differential signaling pathways. NCAM and polysialylated NCAM are aberrantly regulated in breast cancer cells. They are both upregulated in normal breast epithelial cells undergoing EMT. Western blot analysis demonstrates that NCAM-140 overexpression induces EMT in breast epithelial cells and promotes cell proliferation and migration through activation of the β-catenin/slug signaling pathway. Modification of polySia attached to NCAM modulates cell adhesion and promotes cell motility through activation of the EGFR/STAT3 pathway. These observations contribute to clarifying the molecular mechanisms by which polysialic acid and its major substrate, NCAM, modulate cell behaviors, and highlight the significance of increased polysialylated expression on NCAM during EMT and tumor development.

Resveratrol as modulator of PSA-NCAM expression in the hippocampus of diazinon-injured rat fetuses

Polysialylated neural cell adhesion molecule (PSA-NCAM) is expressed in the developing central nervous system (CNS) and plays an important role in neurogenesis. Organophosphorus (OP) toxins, including diazinon (DZN), cause oxidative stress (OS) and damage the CNS. Resveratrol (RV), with its antioxidant effect, leads to the reduction of OS. Therefore, this research was conducted with the aim of the effect of RVon the expression of PSA-NCAM in the hippocampus (HPC) of rat fetuses treated with DZN. In this study, 24 female Wistar rats were divided into 4 groups (n = 6): Control, DZN (40 mg/kg), RV(10 mg/kg), and DZN + RV(40 mg/kg + 10 mg/kg) after confirming they were pregnant. On the 21st day of pregnancy, the mother mice were anesthetized with ketamine and xylazine, and the fetuses were removed; after anesthesia, their brains were removed for immunohistochemistry and western blot (WB) technique. The results of the study showed that in the group receiving DZN, the level of PSA-NCAM protein expression decreased significantly compared to the control group, and the group receiving RV with its antioxidant property increased the expression of PSA-NCAM protein compared to the DZN group. All in all, the exposure of pregnant mice to DZN causes disorders in the CNS, especially the level of PSA-NCAM protein expression in the HPC of fetuses, and the use of RV as an antioxidant by pregnant mothers neutralizes the effects of DZN in the HPC of their fetuses.

Enhanced electrophysiological activity and neurotoxicity screening of environmental chemicals using 3D neurons from human neural precursor cells purified with PSA-NCAM

The assessment of neurotoxicity for environmental chemicals is of utmost importance in ensuring public health and environmental safety. Multielectrode array (MEA) technology has emerged as a powerful tool for assessing disturbances in the electrophysiological activity. Although human embryonic stem cell (hESC)-derived neurons have been used in MEA for neurotoxicity screening, obtaining a substantial and sufficiently active population of neurons from hESCs remains challenging. In this study, we successfully differentiated neurons from a large population of human neuronal precursor cells (hNPC) purified using a polysialylated neural cell adhesion molecule (PSA-NCAM), referred to as hNPCPSA-NCAM+. The functional characterization demonstrated that hNPCPSA-NCAM+-derived neurons improve functionality by enhancing electrophysiological activity compared to total hNPC-derived neurons. Furthermore, three-dimensional (3D) neurons derived from hNPCPSA-NCAM+ exhibited reduced maturation time and enhanced electrophysiological activity on MEA. We employed subdivided population analysis of active mean firing rate (MFR) based on electrophysiological intensity to characterize the electrophysiological properties of hNPCPSA-NCAM+-3D neurons. Based on electrophysiological activity including MFR and burst parameters, we evaluated the sensitivity of hNPCPSA-NCAM+-3D neurons on MEA to screen both inhibitory and excitatory neuroactive environmental chemicals. Intriguingly, electrophysiologically active hNPCPSA-NCAM+-3D neurons demonstrated good sensitivity to evaluate neuroactive chemicals, particularly in discriminating excitatory chemicals. Our findings highlight the effectiveness of MEA approaches using hNPCPSA-NCAM+-3D neurons in the assessment of neurotoxicity associated with environmental chemicals. Furthermore, we emphasize the importance of selecting appropriate signal intensity thresholds to enhance neurotoxicity prediction and screening of environmental chemicals.

Immunological isolation and characterization of neuronal progenitors from human dental pulp: A laboratory-based investigation.

Dental pulp stem cells (DPSCs) contain a population of stem cells with a broad range of differentiation potentials, as well as more lineage-committed progenitors. Such heterogeneity is a significant obstacle to experimental and clinical applications. The aim of this study is to isolate and characterize a homogenous neuronal progenitor cell population from human DPSCs. Polysialylated-neural cell adhesion molecule (PSA-NCAM+) neural progenitors were isolated from the dental pulp of three independent donors using magnetic-activated cell sorting (MACS) technology. Immunofluorescent staining with a panel of neural and non-neural markers was used to characterize the magnetically isolated PSA-NCAM+ fraction. PSA-NCAM+ cells were then cultured in Neurobasal A supplemented with neurotrophic factors: dibutyryl cyclic-AMP, neurotrophin-3, B27 and N2 supplements to induce neuronal differentiation. Both PSA-NCAM+ and differentiated PSA-NCAM+ cells were used in Ca2+ imaging studies to assess the functionality of P2X3 receptors as well as membrane depolarization. PSA-NCAM+ neural progenitors were isolated from a heterogeneous population of hDPSCs using magnetic-activated cell sorting and anti-PSA-NCAM MicroBeads. Flow cytometry analysis demonstrated that immunomagnetic sorting significantly increased the purity of PSA-NCAM+ cells. Immunofluorescent staining revealed expression of pan-neuronal and mature neuronal markers, PGP9.5 and MAP2, respectively, as well as weak expression of the mature sensory markers, peripherin and islet1. ATP-induced response was mediated predominately by P2X3 receptors in both undifferentiated and differentiated cells, with a greater magnitude observed in the latter. In addition, membrane depolarizations were also detected in cells before and after differentiation when loaded with fast-voltage-responding fluorescent molecule, FluoVolt™ in response to potassium chloride. Interestingly, only differentiated PSA-NCAM+ cells were capable of spontaneous membrane oscillations. In summary, DPSCs contain a population of neuronal progenitors with enhanced neural differentiation and functional neural-like properties that can be effectively isolated with magnetic-activated cell sorting (MACS).

K-Ras(V12) differentially affects the three Akt isoforms in lung and pancreatic carcinoma cells and upregulates E-cadherin and NCAM via Akt3

K-Ras is the most frequently mutated Ras variant in pancreatic, colon and non-small cell lung adenocarcinoma. Activating mutations in K-Ras result in increased amounts of active Ras-GTP and subsequently a hyperactivation of effector proteins and downstream signaling pathways. Here, we demonstrate that oncogenic K-Ras(V12) regulates tumor cell migration by activating the phosphatidylinositol 3-kinases (PI3-K)/Akt pathway and induces the expression of E-cadherin and neural cell adhesion molecule (NCAM) by upregulation of Akt3. In vitro interaction and co-precipitation assays identified PI3-Kα as a bona fide effector of active K-Ras4B but not of H-Ras or N-Ras, resulting in enhanced Akt phosphorylation. Moreover, K-Ras(V12)-induced PI3-K/Akt activation enhanced migration in all analyzed cell lines. Interestingly, Western blot analyses with Akt isoform-specific antibodies as well as qPCR studies revealed, that the amount and the activity of Akt3 was markedly increased whereas the amount of Akt1 and Akt2 was downregulated in EGFP-K-Ras(V12)-expressing cell clones. To investigate the functional role of each Akt isoform and a possible crosstalk of the isoforms in more detail, each isoform was stably depleted in PANC-1 pancreatic and H23 lung carcinoma cells. Akt3, the least expressed Akt isoform in most cell lines, is especially upregulated and active in Akt2-depleted cells. Since expression of EGFP-K-Ras(V12) reduced E-cadherin-mediated cell-cell adhesion by induction of polysialylated NCAM, Akt3 was analyzed as regulator of E-cadherin and NCAM. Western blot analyses revealed pronounced reduction of E-cadherin and NCAM in the Akt3-kd cells, whereas Akt1 and Akt2 depletion upregulated E-cadherin, especially in H23 lung carcinoma cells. In summary, we identified oncogenic K-Ras4B as a key regulator of PI3-Kα-Akt signaling and Akt3 as a crucial regulator of K-Ras4B-induced modulation of E-cadherin and NCAM expression and localization.

Prenatal Cannabinoid Exposure Elicits Memory Deficits Associated with Reduced PSA-NCAM Expression, Altered Glutamatergic Signaling, and Adaptations in Hippocampal Synaptic Plasticity.

Cannabis is now one of the most commonly used illicit substances among pregnant women. This is particularly concerning since developmental exposure to cannabinoids can elicit enduring neurofunctional and cognitive alterations. This study investigates the mechanisms of learning and memory deficits resulting from prenatal cannabinoid exposure (PCE) in adolescent offspring. The synthetic cannabinoid agonist WIN55,212-2 was administered to pregnant rats, and a series of behavioral, electrophysiological, and immunochemical studies were performed to identify potential mechanisms of memory deficits in the adolescent offspring. Hippocampal-dependent memory deficits in adolescent PCE animals were associated with decreased long-term potentiation (LTP) and enhanced long-term depression (LTD) at hippocampal Schaffer collateral-CA1 synapses, as well as an imbalance between GluN2A- and GluN2B-mediated signaling. Moreover, PCE reduced gene and protein expression of neural cell adhesion molecule (NCAM) and polysialylated-NCAM (PSA-NCAM), which are critical for GluN2A and GluN2B signaling balance. Administration of exogenous PSA abrogated the LTP deficits observed in PCE animals, suggesting PSA mediated alterations in GluN2A- and GluN2B- signaling pathways may be responsible for the impaired hippocampal synaptic plasticity resulting from PCE. These findings enhance our current understanding of how PCE affects memory and how this process can be manipulated for future therapeutic purposes.

Role of mucin glycosylation in the gut microbiota-brain axis of core 3 O-glycan deficient mice

Alterations in intestinal mucin glycosylation have been associated with increased intestinal permeability and sensitivity to inflammation and infection. Here, we used mice lacking core 3-derived O-glycans (C3GnT−/−) to investigate the effect of impaired mucin glycosylation in the gut-brain axis. C3GnT−/− mice showed altered microbial metabolites in the caecum associated with brain function such as dimethylglycine and N-acetyl-l-tyrosine profiles as compared to C3GnT+/+ littermates. In the brain, polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive granule cells showed an aberrant phenotype in the dentate gyrus of C3GnT−/− mice. This was accompanied by a trend towards decreased expression levels of PSA as well as ZO-1 and occludin as compared to C3GnT+/+. Behavioural studies showed a decrease in the recognition memory of C3GnT−/− mice as compared to C3GnT+/+ mice. Combined, these results support the role of mucin O-glycosylation in the gut in potentially influencing brain function which may be facilitated by the passage of microbial metabolites through an impaired gut barrier.

PSA-NCAM Regulatory Gene Expression Changes in the Alzheimer's Disease Entorhinal Cortex Revealed with Multiplexed in situ Hybridization.

Alzheimer's disease (AD) is the most common form of dementia and is characterized by a substantial reduction of neuroplasticity. Our previous work demonstrated that neurons involved in memory function may lose plasticity because of decreased protein levels of polysialylated neural cell adhesion molecule (PSA-NCAM) in the entorhinal cortex (EC) of the human AD brain, but the cause of this decrease is unclear. To investigate genes involved in PSA-NCAM regulation which may underlie its decrease in the AD EC. We subjected neurologically normal and AD human EC sections to multiplexed fluorescent in situ hybridization and immunohistochemistry to investigate genes involved in PSA-NCAM regulation. Gene expression changes were sought to be validated in both human tissue and a mouse model of AD. In the AD EC, a cell population expressing a high level of CALB2 mRNA and a cell population expressing a high level of PST mRNA were both decreased. CALB2 mRNA and protein were not decreased globally, indicating that the decrease in CALB2 was specific to a sub-population of cells. A significant decrease in PST mRNA expression was observed with single-plex in situ hybridization in middle temporal gyrus tissue microarray cores from AD patients, which negatively correlated with tau pathology, hinting at global loss in PST expression across the AD brain. No significant differences in PSA-NCAM or PST protein expression were observed in the MAPT P301S mouse brain at 9 months of age. We conclude that PSA-NCAM dysregulation may cause subsequent loss of structural plasticity in AD, and this may result from a loss of PST mRNA expression. Due PSTs involvement in structural plasticity, intervention for AD may be possible by targeting this disrupted plasticity pathway.

Wide-ranging migration and destination of early olfactory placode-derived neurons in chick embryos.

Cell migration from the olfactory placode (OP) is a well-known phenomenon wherein various cell types, such as gonadotropin-releasing hormone (GnRH)-producing neurons, migrate toward the telencephalon (TEL) during early embryonic development. However, the spatial relationship between early migratory cells and the forebrain is unclear. We examined the early development of whole-mount chick embryos to observe the three-dimensional spatial relationship among OP-derived migratory neurons, olfactory nerve (ON), and TEL. Migratory neurons that express highly polysialylated neural cell adhesion molecule (PSA-NCAM) emerge from the OP and spread over a relatively wide TEL area at the Hamburger and Hamilton (HH) stage 17. Most migratory neurons form a cellular cord between the olfactory pit and rostral TEL within HH18-20. The earliest axons from the olfactory epithelium (OE) were detected along this neuronal cord using DiI-labeling at HH21. Furthermore, a few PSA-NCAM-positive neurons were dispersed around the cellular cord and over the lateral TEL at HH18. A long cellular cord branch extending to the lateral TEL was transiently observed within HH18-24. These results suggest a novel migratory route of OP-derived neurons during the early developmental stages. Following GFP vector introduction into the OP of HH13-15 embryos, labeled neurons were detected around and within the lateral TEL at HH23 and HH27. At HH36, labeled cells were observed in the rostral-lateral TEL, including the olfactory bulb (OB) region. GFP-labeled and calretinin-positive neurons were detected in the OB, suggesting that early OP-derived neurons enter the forebrain and function as interneurons in the OB.

Transplantation of PSA-NCAM-Positive Neural Precursors from Human Embryonic Stem Cells Promotes Functional Recovery in an Animal Model of Spinal Cord Injury.

Spinal cord injury (SCI) results in permanent impairment of motor and sensory functions at and below the lesion site. There is no therapeutic option to the functional recovery of SCI involving diverse injury responses of different cell types in the lesion that limit endogenous nerve regeneration. In this regard, cell replacement therapyutilizing stem cells or their derivatives has become a highly promising approach to promote locomotor recovery. For this reason, the demand for a safe and efficient multipotent cell source that can differentiate into various neural cells is increasing. In this study, we evaluated the efficacy and safety of human polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive neural precursor cells (hNPCsPSA-NCAM+) as a treatment for SCI. One hundred thousand hNPCsPSA-NCAM+ isolated from human embryonic stem cell-derived NPCs were transplanted into the lesion site by microinjection 7days after contusive SCI at the thoracic level. We examined the histological characteristics of the graft and behavioral improvement in the SCI rats 10weeks after transplantation. Locomotor activity improvement was estimated by the Basso-Beattie-Bresnahan locomotor rating scale. Behavioral tests revealed that the transplantation of the hNPCsPSA-NCAM+ into the injured spinal cords of rats significantly improved locomotor function. Histological examination showed that hNPCsPSA-NCAM+ had differentiated into neural cells and successfully integrated into the host tissue with no evidence of tumor formation. We investigated cytokine expressions, which led to the early therapeutic effect of hNPCsPSA-NCAM+, and found that some undifferentiated NPCs still expressed midkine, a well-known neurotrophic factor involved in neural development and inflammatory responses, 10weeks after transplantation. Our results demonstrate that hNPCsPSA-NCAM+ serve as a safe and efficient cell source which has the potential to improve impaired motor function following SCI.

Autonomic Nerves Regulate Gene Expression Profiles in The Developing Ductus Arteriosus

Background The ductus arteriosus (DA), a bypass vessel between the aorta and main pulmonary artery, is essential for fetal circulation, and immediately closes after birth. Prostaglandin E2 plays important roles in both DA patency and closure via its receptor EP4. During the fetal periods, EP4 signaling dilates the DA through inhibition of myosin light chain kinase and promotes luminal narrowing, i.e., intimal thickening, for complete closure of the DA after birth when placental PGE2 is dramatically decreased. Previous studies have demonstrated that EP4 is prominently expressed in the developing DA and EP4-deficient mice exhibits patent DA after birth, suggesting that EP4 expression in the DA is critical for adaptation from fetal and adult circulatory system. However, the molecular mechanism of specific expression of EP4 in the DA is unknown. It has been reported that sympathetic nerves are distributed around the DA. Therefore, we hypothesized that sympathetic nerves regulated EP4 expression in the DA. In this study, we aimed to investigate the molecular mechanism of EP4 expression in the DA. Methods We generated EP4 reporter mice with EP4-IRES-nlsLacZ. EP4 reporter mice were stained with X-gal, and then tissue sections were prepared. We examined neurite outgrowth by immunohistochemistry with an antibody against polysialylated neural cell adhesion molecule (PSA-NCAM). Distribution of autonomic nerve terminals were detected by immunohistochemistry with an antibody against tyrosine hydroxylase. Results X-gal staining showed that no EP4 expression was observed in the DA at embryonic day 13 (E13). At E14, EP4 expression was observed in the smooth muscle layer of the DA, which was stronger in the outer layer (Figure 1). At E18.5 (full-term), EP4 expression level was significantly higher than pre-term mice and EP4 was uniformly expressed throughout the tunica media of the DA. At postnatal day 2, EP4 expression was decreased throughout the smooth muscle layer of the DA. No visible EP4 expression was observed in the smooth muscle layers of adjacent arteries. i.e., the aorta and pulmonary arteries, and endothelial cells of the DA and adjacent arteries. PSA-NCAM-positive neurites invaded into the adventitia toward the smooth muscle layer of the DA at E13, in which EP4 was not yet expressed. Neurite outgrowth became prominent in the tunica media in the DA at E14 (Figure 2). At full-term, neurites were observed throughout the smooth muscle layer of the DA, which was consistent with the area of the EP4 expression. Neurite outgrowth into the tunica media was not observed in the adjacent arteries. Furthermore, tyrosine hydroxylase was observed in the outer layer of the tunica media and the adventitia in the DA, indicating the presence of autonomic nerve terminals in the DA. Conclusion Sympathetic nerves may regulate specific expression of EP4 in the DA. These data suggest the novel epigenetic regulation of autonomic nerve-mediated vascular development.

Analysis of homozygous and heterozygous Csf1r knockout in the rat as a model for understanding microglial function in brain development and the impacts of human CSF1R mutations

Mutations in the human CSF1R gene have been associated with dominant and recessive forms of neurodegenerative disease. Here we describe the impacts of Csf1r mutation in the rat on development of the brain. Diffusion imaging indicated small reductions in major fiber tracts that may be associated in part with ventricular enlargement. RNA-seq profiling revealed a set of 105 microglial markers depleted in all brain regions of the Csf1rko rats. There was no evidence of region or sex-specific expression of microglia-associated transcripts. Other than the microglial signature, Csf1rko had no effect on any neuronal or region-specific transcript cluster. Expression of markers of oligodendrocytes, astrocytes, dopaminergic neurons and Purkinje cells was minimally affected. However, there were defects in dendritic arborization of doublecortin-positive neurogenic precursors and expression of poly-sialylated neural cell adhesion molecule (PS-NCAM) in the dentate gyrus of the hippocampus. Heterozygous Csf1rko rats had no detectable brain phenotype. We conclude that most brain developmental processes occur normally in the absence of microglia and that CSF1R haploinsufficiency is unlikely to cause leukoencephalopathy.

Polysialylated – neural cell adhesion molecule (PSA-NCAM) promotes recovery of vision after the critical period

Vision loss has long since been considered irreversible after a critical period; however, there is potential to restore limited vision, even in adulthood. This phenomenon is particularly pronounced following complete loss of vision in the dominant eye. Adult neural cell adhesion molecule (NCAM) knockout mice have an age-related impairment of visual acuity. The underlying cause of early deterioration in visual function remains unknown. Polysialylated (PSA) NCAM is involved in different forms of neural plasticity in the adult brain, raising the possibility that NCAM plays a role in the plasticity of the visual cortex, and therefore, in visual ability. Here, we examined whether PSA-NCAM is required for visual cortical plasticity in adult C57Bl/6J mice following deafferentation and long-term monocular deprivation. Our results show that elevated PSA in the contralateral visual cortex of the reopened eye is accompanied by changes in other markers of neural plasticity: increased brain-derived neurotrophic factor (BDNF) levels and degradation of perineuronal nets (PNNs). The removal of PSA-NCAM in the visual cortex of these mice reduced BDNF expression, decreased PNN degradation, and resulted in impaired recovery of visual acuity after optic nerve transection and chronic monocular deprivation. Collectively, our results demonstrate that PSA-NCAM is necessary for the reactivation of visual cortical plasticity and recovery of visual function in adult mice. It also offers a potential molecular target for the therapeutic treatment of cortically based visual impairments.

Aberrant glycosylation in schizophrenia: a review of 25 years of post-mortem brain studies.

Glycosylation, the enzymatic attachment of carbohydrates to proteins and lipids, regulates nearly all cellular processes and is critical in the development and function of the nervous system. Axon pathfinding, neurite outgrowth, synaptogenesis, neurotransmission, and many other neuronal processes are regulated by glycans. Over the past 25 years, studies analyzing post-mortem brain samples have found evidence of aberrant glycosylation in individuals with schizophrenia. Proteins involved in both excitatory and inhibitory neurotransmission display altered glycans in the disease state, including AMPA and kainate receptor subunits, glutamate transporters EAAT1 and EAAT2, and the GABAA receptor. Polysialylated NCAM (PSA-NCAM) and perineuronal nets, highly glycosylated molecules critical for axonal migration and synaptic stabilization, are both downregulated in multiple brain regions of individuals with schizophrenia. In addition, enzymes spanning several pathways of glycan synthesis show differential expression in brains of individuals with schizophrenia. These changes may be due to genetic predisposition, environmental perturbations, medication use, or a combination of these factors. However, the recent association of several enzymes of glycosylation with schizophrenia by genome-wide association studies underscores the importance of glycosylation in this disease. Understanding how glycosylation is dysregulated in the brain will further our understanding of how this pathway contributes to the development and pathophysiology of schizophrenia.

Prenatal Cannabinoid Exposure Mediated Cognitive Deficits in the Offspring: Elucidation of the Mechanism and Identifying Therapeutic Targets

Cannabinoid is currently one of the most commonly used recreational drugs in the world with an approximate user of 22.2 million. As more and more states in the US are legalizing the use of cannabinoid, the rate of cannabinoid use is increasing specially in pregnant women. The active ingredient of cannabis is delta‐9‐tetrahydrocannabinol (THC) which can cross blood placental barrier and may cause enduring alterations in synaptic circuitry of the fetal brain. The aim of our study is to investigate the mechanism of learning and memory deficits in case of prenatal cannabinoid exposure (PCE) in the adolescent offspring. An osmotic pump filled with either vehicle or the cannabinoid receptor full agonist WIN55,212‐2 (2 mg/kg body weight/day) was implanted subcutaneously in Gestational Day‐3 to deliver the drug at a constant rate until the pups were born. Open field test was performed to see the effect of PCE on locomotor activity which revealed no abnormality in the general motor activity. Contextual fear conditioning test indicated a significantly reduced freezing behavior in the PCE group compared to the vehicle exposed group. Hippocampus based spatial memory test Morris water maze showed that during the trial period, PCE animals exhibit no preference for any particular quadrant while control animals had an increased preference for the quadrant where the hidden platform was present during the training period. Electrophysiological experiments were performed on the Schaffer collateral pathway of acute hippocampal slices to measure synaptic plasticity. Impairment in both long term potentiation (LTP) and long‐term depression (LTD), which are important parameters of synaptic plasticity, were observed. These impairments were associated with downstream changes in the glutamatergic signaling. An increase in cannabinoid receptor type 1(CB1) expression followed by reduced neural cell adhesion molecule (NCAM) and its active form polysialylated NCAM (PSA‐NCAM) expression have been observed in the hippocampus of PCE animals. Interestingly, restoration of PSA‐NCAM activity restored the LTP deficits observed in PCE animals. Thus, based on the previous studies and our current data, it can be postulated that, the observed cognitive deficits in the PCE animals might be partly due to an imbalance in glutamate receptors mediated neurotransmission influenced by NCAM/PSA NCAM. Understanding this specific NCAM/PSA‐NCAM interdependent signaling cascade will lead to an identification of a specific therapeutic target to improve gestational cannabinoid exposure mediated memory deficits.

Myrtus communis subsp. communis improved cognitive functions in ovariectomized diabetic rats.

The purpose of this study was to investigate the possible effects of Myrtus communis subsp. communis (MC) on cognitive impairment in ovariectomized diabetic rats. Female Sprague-Dawley rats were divided into 5 groups consisting of 15 rats each; Control (C), Diabetes (D), Ovariectomy and diabetes (OVX+D), Ovariectomy, diabetes and donepezil (OVX+D+Don), Ovariectomy, diabetes and Myrtus communis subsp. communis (OVX+D+MC). Blood glucose measurements were made at the beginning and end of the experiments. The animals underwent the novel object recognition test (NORT) and their performance was evaluated. In hippocampal tissues; amyloid beta (Aβ) and neprilysin levels, acetylcholinesterase (AChE), and choline acetyltransferase (ChAT) activities, polysialylated neural cell adhesion molecule (PSA-NCAM), α7 subunit of neuronal nicotinic acetylcholine receptor (α7-nAChR) and brain derived neurotrophic factor (BDNF) gene expressions were examined. Animals with ovariectomy and diabetes showed increased levels of blood glucose, AChE activity and Aβ levels, and decreased neprilysin levels, ChAT activity, α7-nAChR, PSA-NCAM and BDNF gene expressions in parallel with a decrease in NORT performance score. On the other hand, in the MC-treated OVX+D group, there was a significant decrease observed in blood glucose levels and AChE activities while there was improvement in NORT performances and an increase in hippocampal ChAT activity, neprilysin levels, α7-nAChR, PSA-NCAM and BDNF expressions. These results suggest that MC extract could improve cognitive and neuronal functions with its anticholinesterase and antihyperglycemic properties.

Neurotrophic factors in the posterodorsal medial amygdala of male and cycling female rats

The posterodorsal medial amygdala (MePD) has a high concentration of receptors for gonadal hormones, is a sexually dimorphic region and dynamically controls the reproductive behavior of both males and females. Neurotrophic factors can promote dendritic spine remodeling and change synaptic input strength in a region-specific manner. Here, we analyzed the gene and protein expression of brain-derived neurotrophic factor (BDNF), insulin-like growth factor-I (IGF-1), polysialylated neural cell adhesion molecule (PSA-NCAM) and Ephrin-A4 in the MePD of adult males and females in diestrus, proestrus and estrus using real-time qPCR and fluorescent immunohistochemistry. The first approach showed their amplification except for Igf1 and the latter revealed that BDNF, IGF-1, PSA-NCAM and Ephrin-A4 are expressed in the MePD of the adult rats. Protein expression of these neurotrophic factors showed no differences between groups. However, proestrus females displayed a higher number of labelled puncta than males for BDNF expression and diestrus females for IGF-1 expression. In conjunction, results indicate that IGF-1 might be released rather than synthetized in the MePD, and the expression of specific neurotrophic factors varies specifically during proestrus. The dynamic modulation of BDNF and IGF-1 during this cyclic phase is coincident with synaptic changes and spine density remodeling in the MePD, the disinhibition of gonadotrophin secretion for ovulation and the display of sexual behavior.

Engineered antibody-functionalized porous silicon nanoparticles for therapeutic targeting of pro-survival pathway in endogenous neuroblasts after stroke

Generation of new neurons by utilizing the regenerative potential of adult neural stem cells (NSCs) and neuroblasts is an emerging therapeutic strategy to treat various neurodegenerative diseases, including neuronal loss after stroke. Committed to neuronal lineages, neuroblasts are differentiated from NSCs and have a lower proliferation rate. In stroke the proliferation of the neuroblasts in the neurogenic areas is increased, but the limiting factor for regeneration is the poor survival of migrating neuroblasts. Survival of neuroblasts can be promoted by small molecules; however, new drug delivery methods are needed to specifically target these cells. Herein, to achieve specific targeting, we have engineered biofunctionalized porous silicon nanoparticles (PSi NPs) conjugated with a specific antibody against polysialylated neural cell adhesion molecule (PSA-NCAM). The PSi NPs loaded with a small molecule drug, SC-79, were able to increase the activity of the Akt signaling pathway in doublecortin positive neuroblasts both in cultured cells and in vivo in the rat brain. This study opens up new possibilities to target drug effects to migrating neuroblasts and facilitate differentiation, maturation and survival of developing neurons. The conjugated PSi NPs are a novel tool for future studies to develop new therapeutic strategies aiming at regenerating functional neurocircuitry after stoke.

Resveratrol Regulates BDNF, trkB, PSA-NCAM, and Arc Expression in the Rat Cerebral Cortex after Bilateral Common Carotid Artery Occlusion and Reperfusion.

The polyphenol resveratrol (RVT) may drive protective mechanisms of cerebral homeostasis during the hypoperfusion/reperfusion triggered by the transient bilateral common carotid artery occlusion followed by reperfusion (BCCAO/R). This immunochemical study investigates if a single dose of RVT modulates the plasticity-related markers brain-derived neurotrophic factor (BDNF), the tyrosine kinase trkB receptor, Polysialylated-Neural Cell Adhesion Molecule (PSA-NCAM), and Activity-regulated cytoskeleton-associated (Arc) protein in the brain cortex after BCCAO/R. Frontal and temporal-occipital cortical regions were examined in male Wistar rats randomly subdivided in two groups, sham-operated and submitted to BCCAO/R. Six hours prior to surgery, half the rats were gavage fed a dose of RVT (180 mg·kg−1 in 300 µL of sunflower oil as the vehicle), while the second half was given the vehicle alone. In the frontal cortex of BCCAO/R vehicle-treated rats, BDNF and PSA-NCAM decreased, while trkB increased. RVT pre-treatment elicited an increment of all examined markers in both sham- and BCCAO/R rats. No variations occurred in the temporal-occipital cortex. The results highlight a role for RVT in modulating neuronal plasticity through the BDNF-trkB system and upregulation of PSA-NCAM and Arc, which may provide both trophic and structural local support in the dynamic changes occurring during the BCCAO/R, and further suggest that dietary supplements such as RVT are effective in preserving the tissue potential to engage plasticity-related events and control the functional response to the hypoperfusion/reperfusion challenge.