Postsynaptic Density Protein Research Articles

Increased astrocytic GLT-1 expression in tripartite synapses is associated with SCI-induced hyperreflexia.

Spasticity is a chronic neurological complication associated with spinal cord injury (SCI), characterized by increased muscle tone and stiffness. A physiological sign of spasticity is hyperreflexia, evident by the loss of evoked rate-dependent depression (RDD) in the H-reflex. Although previous work has shown that SCI-induced astrogliosis contributes to hyperexcitability disorders, including neuropathic pain and spasticity, it is unclear how reactive astrocytes can modulate synaptic transmission within the injured spinal cord. To study astrocytes' role in post-SCI hyperreflexia, we examined glutamate transporter-1 (GLT-1) and postsynaptic density protein 95 (PSD-95) proteins in astrocytes and neurons, respectively, within the ventral horn (lamina IX) below the level of injury (spinal segment L4-5). The close juxtaposition of GLT-1 and PSD-95 markers is a molecular correlate of tripartite synapses and is thought to be a key element in the astrocyte-induced plasticity of neuronal synapses. Our study compared animals with and without SCI-induced hyperreflexia and spasticity and investigated potential synaptic abnormalities associated with astrocyte involvement. As expected, 4 wk after SCI, we observed a loss in evoked H-reflex RDD in hindlimb electromyogram recordings, i.e., hyperreflexia, in contrast to uninjured sham. Importantly, our main findings show a significant increase in the presence of GLT-1-PSD-95 tripartite synapses in the ventral spinal cord motor regions of animals exhibiting SCI-induced hyperreflexia. Taken together, our study suggests the involvement of astrocyte-neuron synaptic complexes in the plasticity-driven progression of chronic spasticity.NEW & NOTEWORTHY The role of astrocytes in H-reflex hyperexcitability following SCI remains understudied. Our findings establish a relationship between GLT-1 expression, its proximity to neuronal PSD-95 in the spinal cord ventral horn, and the loss of H-reflex RDD, i.e., hyperreflexia. Our findings provide a new perspective on synaptic alterations and the development of SCI-related spasticity.

Li, P HY-021068 alleviates cerebral ischemia-reperfusion injury by inhibiting NLRP1 inflammasome and restoring autophagy function in mice

Cerebral ischemia-reperfusion injury (CIRI) is a severe pathological condition that involves oxidative stress, inflammatory response, and neuronal damage. HY-021068 belongs to a new drug of chemical class 1, which is a potential thromboxane synthase inhibitor. Our preliminary experiment found that HY-021068 has significant anti-neuroinflammatory and neuroprotective effects. However, the protective effect and mechanism of HY-021068 in CIRI remain unclear. To investigate the protective effect and mechanism of HY-021068 in CIRI mice. In mice, CIRI was induced by bilateral common carotid artery occlusion and reperfusion. Mice were treated with HY-021068 or LV-NLRP1-shRNA (lentivirus-mediated shRNA transfection to knock down NLRP1 expression). The locomotor activity, neuronal damage, pathological changes, postsynaptic density protein-95 (PSD-95) expression, NLRP1 inflammasome activation, autophagy markers, and apoptotic proteins were assessed in CIRI mice. In this study, treatment with HY-021065 and LV-NLRP1-shRNA significantly improved motor dysfunction and neuronal damage after CIRI in mice. HY-021065 and NLRP1 knockdown significantly ameliorated the pathological damage and increased PSD-95 expression in the cortex and hippocampus CA1 and CA3 regions. The further studies showed that compared with the CIRI model group, HY-021065 and NLRP1 knockdown treatment inhibited the expressions of NLRP1, ASC, caspase-1, and IL-1β, restored the expressions of p-AMPK/AMPK, Beclin1, LC3II/LC3I, p-mTOR/m-TOR and P62, and regulated the expressions of BCL-2, Caspase3, and BAX in brain tissues of CIRI mice in CIRI mice. These results suggest that HY-021068 exerts a protective role in CIRI mice by inhibiting NLRP1 inflammasome activation and regulating autophagy function and neuronal apoptosis. HY-021068 is expected to become a new therapeutic drug for CIRI.

A Ketogenic Diet may Improve Cognitive Function in Rats with Temporal Lobe Epilepsy by Regulating Endoplasmic Reticulum Stress and Synaptic Plasticity.

A ketogenic diet (KD) is often used in the treatment of refractory epilepsy. Many studies have found that it also has a positive impact on cognitive comorbidities, but the specific mechanism remains unclear. In many disease models, endoplasmic reticulum stress (ERS) and synaptic plasticity is considered a new therapeutic target for improving cognitive impairment, and it has become a research focus in recent years. Recently, studies have found that a KD has a certain regulatory effect on both ERS and synaptic plasticity, but this result has not been confirmed in epilepsy. To investigate the effect of a KD on ERS and synaptic plasticity. In this study, a rat model of temporal lobe epilepsy (TLE) induced by lithium chloride-pilocarpine was used. After the model was successfully established, the rats in each group were fed a normal diet or a KD for 28 days, and the effect of a KD on the latency and seizure frequency of spontaneous recurrent seizures (SRSs) was observed via video monitoring. Subsequently, a Morris water maze was used to evaluate the spatial learning and memory abilities of the rats in each group; the ultrastructure of the ER and the synapses of the hippocampus were observed by transmission electron microscopy, and the dendritic spine density of the hippocampus was analysed by Golgi staining. Long-term potentiation (LTP) was used to detect the synaptic plasticity of the rats' hippocampi, and the expression of ERS-related proteins and synapse-related proteins was detected by Western blotting. A KD effectively reduced the frequency of SRSs in rats with TLE and improved their learning and memory impairment. Further investigations found that a KD inhibited the up-regulation of glucose-regulated protein 78, phospho-protein kinase-like ER kinase, phosphorylated α subunit of eukaryotic initiation factor 2, activating transcription factor 4 and C/EBP homologous protein expression in the hippocampi of rats with TLE and protected the ultrastructure of the neuronal ER, suggesting that a KD suppressed excessive ERS induced by epilepsy. Concurrently, we also found that a KD not only improved the synaptic ultrastructure and increased the density of dendritic spines in rats with TLE but also reversed the epilepsy-induced LTP deficit to some extent. More importantly, the expression of postsynaptic density protein 95, synaptotagmin-1 and synaptosomal-associated protein 25 in the hippocampi of rats with epilepsy was significantly increased after KD intervention. The study findings indicate that a KD improves learning and memory impairment in rats with epilepsy, possibly by regulating ERS and synaptic plasticity.

Histone deacetylase inhibitor attenuates the effects of 27-hydroxycholesterol on the rat brain

Hypercholesterolemia is a risk factor for Alzheimer’s disease (AD). Plasma cholesterol does not pass the blood–brain barrier whereas its metabolite 27-hydroxycholesterol (27-OHC) can enter the brain. High 27-OHC in the brain has been suggested to mediate hypercholesterolemia-induced impairments of learning and memory through promoting amyloid-β accumulation and facilitating synaptic disruption. In AD brains, the activity of histone deacetylase (HDAC) is elevated. Treating AD animals with HDAC inhibitors decreases amyloid-β levels and synaptic damages, which leads to memory improvement. Whether HDAC activity is involved in the actions of 27-OHC is still uncertain. In this study, 4 weekly injections of 27-OHC/vehicle were given to rats followed by 3 daily injections of HDAC inhibitor trichostatin (TSA)/vehicle. The results of Morris water maze test reveal that all rats have intact spatial learning ability during the 5-d training phase. However, the behavioral performance during the probe trial was impaired by 27-OHC treatment, which was improved by adding TSA treatments. Furthermore, 27-OHC treatments reduced the hippocampal levels of acetylated histone H3, acetylated α tubulin, insulin-degrading enzyme and postsynaptic protein PSD-95, indicating that 27-OHC treatments may induce enhanced HDAC activity, decreased amyloid-β clearance and synaptic disruption. All reduced levels returned to the basal levels by adding TSA treatments. These findings support our hypothesis that HDAC activity is enhanced following long-term exposure to excess 27-OHC.

Electroacupuncture at GB20 improves cognitive ability and synaptic plasticity via the CaM-CaMKII-CREB signaling pathway following cerebral ischemia-reperfusion injury in rats.

This study aimed to investigate the effects of electroacupuncture (EA) on cognitive recovery and synaptic remodeling in a rat model of middle cerebral artery occlusion (MCAO) followed by reperfusion and explore the possible mechanism. Focal cerebral ischemia was modeled in healthy adult Sprague-Dawley rats by MCAO. The MCAO rats were classified into four groups: sham, MCAO, MCAO + GB20 (receiving EA at GB20) and MCAO + NA (receiving EA at a "non-acupoint" location not corresponding to any traditional acupuncture point location about 10 mm above the iliac crest). Neurological deficit scores and behavior were assessed before and during the treatment. After intervention for 7 days, the hippocampus was dissected to analyze growth-associated protein (GAP)-43, synaptophysin (SYN) and postsynaptic density protein (PSD)-95 expression levels by Western blotting. Bioinformatic analysis and primary hippocampal neurons with calcium-voltage gated channel subunit alpha 1B (CACNA1B) gene overexpression were used to screen the target genes for EA against MCAO. Significant amelioration of neurological deficits and learning/memory were found in MCAO + GB20 rats compared with MCAO or MCAO + NA rats. Protein levels of GAP-43, SYN and PSD-95 were significantly improved in MCAO + GB20-treated rats together with an increase in the number of synapses in the hippocampal CA1 region. CACNA1B appeared to be a target gene of EA in MCAO. There were increased mRNA levels of CACNA1B, calmodulin (CaM), Ca2+/calmodulin-dependent protein kinase type II (CaMKII) and cyclic adenosine monophosphate response element binding (CREB) and increased phosphorylation of CaM, CaMKII and CREB in the hippocampal region in MCAO + GB20 versus MCAO and MCAO + NA groups. CACNA1B overexpression modulated expression of the CaM-CaMKII-CREB axis. EA treatment at GB20 may ameliorate the negative effects of MCAO on cognitive function in rats by enhancing synaptic plasticity. EA treatment at GB20 may exert this neuroprotective effect by regulating the CACNA1B-CaM-CaMKII-CREB axis.

Discovery of benzyloxy benzamide derivatives as potent neuroprotective agents against ischemic stroke

Aberrant activation of N-methyl-d-aspartate receptors (NMDAR) and the resulting neuronal nitric oxide synthase (nNOS) excessive activation play crucial pathogenic roles in neuronal damage caused by stroke. Disrupting postsynaptic density protein 95 (PSD95)-nNOS protein-protein interaction (PPI) has been proposed as a potential therapeutic strategy for ischemic stroke without incurring the unwanted side effects of direct NMDAR antagonism. Based on a specific PSD95-nNOS PPI inhibitor (SCR4026), we conducted a detailed study on structure-activity relationship (SAR) to discover a series of novel benzyloxy benzamide derivatives. Here, our efforts resulted in the best 29 (LY836) with improved neuroprotective activities in primary cortical neurons from glutamate-induced damage and drug-like properties. Whereafter, co-immunoprecipitation experiment demonstrated that 29 significantly blocked PSD95-nNOS association in cultured cortical neurons. Furthermore, 29 displayed good pharmacokinetic properties (T1/2 = 4.26 and 4.08 h after oral and intravenous administration, respectively) and exhibited powerful therapeutic effects in rats subjected to middle cerebral artery occlusion (MCAO) by reducing infarct size and neurological deficit score. These findings suggested that compound 29 may be a promising neuroprotection agent for the treatment of ischemic stroke.

Bio-clickable, small extracellular vesicles-COCKTAIL therapy for ischemic stroke

Delivering large therapeutic molecules via the blood-brain barrier to treat ischemic stroke remains challenging. NR2B9c is a potent neuroprotective peptide but it's safe and targeted delivery to the brain requires an efficient, natural, and non-immunogenic delivery technique. Small extracellular vesicles (sEVs) have shown great potential as a non-immunogenic, natural cargo delivery system; however, tailoring of its inefficient brain targeting is desired. Here, we coupled rabies virus glycoprotein 29 with sEVs surface via bio-orthogonal click chemistry reactions, followed by loading of NR2B9c, ultimately generating stroke-specific therapeutic COCKTAIL (sEVs-COCKTAIL). Primary neurons and Neuro-2a cells were cultured for in vitro and transient middle cerebral artery occlusion model was used for in vivo studies to evaluate neuron targeting and anti-ischemic stroke potential of the sEVs-COCKTAIL. Bio-clickable sEVs were selectively taken up by neurons but not glial cells. In the in vitro ischemic stroke model of oxygen-glucose deprivation, the sEVs-COCKTAIL exhibited remarkable potential against reactive oxygen species and cellular apoptosis. In vivo studies further demonstrated the brain targeting and increased half-life of bio-clickable sEVs, delivering NR2B9c to the ischemic brain and reducing stroke injury. Treatment with the sEVs-COCKTAIL significantly increased behavioral recovery and reduced neuronal apoptosis after transient middle cerebral artery occlusion. NR2B9c was delivered to neurons binding to post-synaptic density protein-95, inhibiting N-methyl-d-Aspartate receptor-mediated over production of oxidative stress and mitigating protein B-cell lymphoma 2 and P38 proteins expression. Our results provide an efficient and biocompatible approach to a targeted delivery system, which is a promising modality for stroke therapy.

Neuroprotective mechanism of walnut-derived peptide via C1q-mediated synaptic plasticity in HT22 cells

Synaptic dysfunction is a precursor of cognitive decline and memory impairment in neurodegenerative diseases. The complement component 1q (C1q), and complement pathway contribute to synaptic loss and plasticity, leading to nerve damage. The walnut-derived peptide TWLPLPR (TW-7) has beneficial effect on nerve protection. However, its specific mechanisms are still not fully understood, particularly in C1q-mediated synaptic plasticity. We investigated the neuroprotective effects of TW-7, and the mechanism of C1q-mediated synaptic plasticity in hydrogen peroxide (H2O2)-induced HT22 cells. Treatment with C1q gene plasmid overexpression in HT22 cells showed that TW-7 reduced C1q expression, thus decreasing complement three (C3) expression and increasing the presynaptic protein SYP and postsynaptic protein PSD95. Molecular docking confirmed that TW-7 binding to the recognition site of C1q and reduce synaptic loss. Furthermore, TW-7 inhibited local apoptosis and mediated the phosphoinositide 3-kinase/Programmable Logic Controller/IP3 receptor pathway to maintain intracellular Ca2+ homeostasis and improve synaptic plasticity. Our results suggest that TW-7 exerts a neuroprotective effect in HT22 cells by C1q-mediated synaptic plasticity.

Sec8 specifically interacts with the PDZ2 domain of synapse associated protein 102 (SAP102).

The exocyst is an evolutionarily conserved protein complex tethering secretory vesicles before their docking and fusion with the plasma membrane. The complex also plays important roles in cell migration, synaptogenesis, and neurite outgrowth. One of its subunits, Sec8, was reported to interact with two major synaptic scaffolding proteins SAP102 and PSD-95 that share high sequence homology and contain three PDZ domains at their N-terminal region. The interaction is via the binding of the C-terminal ITTV motif in Sec8 to the PDZ domains of the two synaptic proteins. However, it remains elusive to which PDZ domain(s) Sec8 binds and how their interaction occurs. Here we reported a 2.5Å resolution crystal structure of the C-terminal half of rat Sec8 containing the ITTV motif. The structure shows that Sec8 contains an enormously long helix at its C-terminus, which bears a unique long "spacer" of 14 residues to bridge the ITTV motif to the compact core of Sec8. We found that Sec8 preferentially binds PDZ2 over PDZ1 and PDZ3 of SAP102. Deletion of the spacer completely abolished the binding of Sec8 to SAP102. Overall, our structural studies, biochemical data and modeling analyses altogether provide an explanation for how Sec8 interacts with SAP102.

Spinosin protects Neuro-2a/APP695 cells from oxidative stress damage by inactivating p38.

To explore the protective mechanism of spinosin (SPI) on Alzheimer's disease (AD) model cells, Neuro-2a/APP695 (N2a/APP695), against HO-induced oxidative stress damage, to reflect the influence of oxidative stress on the development of AD, and to provide a valuable basis for the research and development of therapeutic drug for AD. N2a/APP695 cells were exposed to HO and then treated with spinosin. Firstly, the secretion level of amyloid β (Aβ) and the production of malondialdehyde (MDA) and lactate dehydrogenase (LDH) were detected by enzyme linked immunosorbent assay kits. Secondly, the oligomerization degree of Aβ was performed by Thioflavin T staining. Thirdly, the expression levels of p-Tau (Ser199/202/396), synaptophysin (SYP), postsynaptic density protein 95 (PSD95), and mitogen-activated protein kinase (MAPK) family-related proteins were detected by Western blot analysis. In addition, FITC-labeled phalloidin was used in cytoskeleton staining to reflect synaptic function. This study showed that HO stimulated N2a/APP695 cells to produce excessive MDA and LDH and secrete a large amount of Aβ, promoted the aggregation of Aβ, induced Tau protein hyperphosphorylation, and led to synaptic dysfunction. Spinosin reversed these changes caused by HO by inactivating p38, which was verified by treatment with the p38 inhibitor BIRB796. Spinosin protects N2a/APP695 cells from oxidative stress damage caused by HO through inactivating p38.

Huangdi Anxiao Capsules-containing serum protects cell model from cognitive dysfunction in diabetes via inhibiting NLRP3-mediated pyroptosis

This study aims to investigate the effects and the molecular mechanism of Huangdi Anxiao Capsules(HDAX)-containing serum in protecting the rat adrenal pheochromocytoma(PC12) cells from diabetes-associated cognitive dysfunction induced by high glucose and whether the mechanism is related to the regulation of NOD-like receptor thermal protein domain associated protein 3(NLRP3)-mediated pyroptosis. The PC12 cell model of diabetes-associated cognitive dysfunction induced by high glucose was established and mcc950 was used to inhibit NLRP3. PC12 cells were randomized into control, model, HDAX-containing serum, mcc950, and HDAX-containing serum+mcc950 groups. Methyl thiazolyl tetrazolium(MTT) assay was employed to determine the viability, and Hoechst 33258/PI staining to detect pyroptosis of PC12 cells. Enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of interleukin-1 beta(IL-1β) and IL-18. Western blot was employed to determine the protein levels of postsynaptic density protein 95(PSD-95), NLRP3, apoptosis-associated speck-like protein containing a CARD(ASC), gasdermin D(GSDMD), GSDMD-N, and cleaved cysteinyl aspartate specific proteinase-1(caspase-1), and RT-PCR to determine the mRNA levels of NLRP3, ASC, GSDMD, and caspase-1. The immunofluorescence assay was adopted to measure the levels and distribution of NLRP3 and GSDMD-N in PC12 cells. Compared with the control group, the model group showed decreased cell proliferation, increased PI positive rate, down-regulated protein level of PSD-95, up-regulated protein levels of NLRP3, ASC, GSDMD-N, GSDMD, and cleaved caspase-1, up-regulated mRNA levels of NLRP3, ASC, GSDMD, and caspase-1, and elevated levels of IL-1β and IL-18. Compared with the model group, HDAX-containing serum, mcc950, and the combination of them improved cell survival rate and morphology, decreased the PI positive rate, down-regulated the protein levels of NLRP3, ASC, GSDMD-N, GSDMD, and cleaved caspase-1 and the mRNA levels of NLRP3, ASC, GSDMD, and caspase-1, and promoted the secretion of IL-1β and IL-18. The findings demonstrated that HDAX-containing serum can inhibit the pyroptosis-mediated by NLRP3 and protect PC12 cells from the cognitive dysfunction induced by high glucose.

Electroacupuncture improves learning and memory impairment and enhances hippocampal synaptic plasticity through BDNF/TRKB/CREB signaling pathway in cerebral ischemia-reperfusion injury rats

To observe the effect of electroacupuncture on brain-derived neurotrophin factor (BDNF) / tyrosine kinase receptor B (TRKB) / cyclic adenosine monophosphate response element binding protein (CREB) pathway, synaptic plasticity marker protein and synaptic ultrastructure in the hippocampus of rats with learning and memory impairment induced by cerebral ischemia reperfusion (IR), so as to explore its mechanisms underlying improvement of cognitive impairment after stroke. SD rats were randomly divided into blank, sham operation, model, and EA groups, with 12 rats in each group. The model of IR was established by occlusion of the middle cerebral artery. EA (2 Hz/10 Hz, 1-3 mA) was applied to "Shenting" (GV24) and "Baihui" (GV20) for 30 min, once daily for 14 days. The neurological function was evaluated according to the Zea Longa's score criteria. Morris water maze test was used to detect the learning and memory function of the rats. Nissl staining was used to observe the pathological morphology of the hippocampus. Transmission electron microscopy was used to observe the ultrastructure of the syna-pse in the hippocampus, the synaptic gap width and postsynaptic dense substance (PSD) thickness were measured. Immunofluorescence staining was used to observe the positive expression levels of BDNF, PSD-95 and synaptophysin (SYN) in hippocampal CA1 region. The protein expression levels of BDNF, TRKB, CREB, PSD-95, and SYN in hippocampal tissue were detected by Western blot. Compared with the sham operation group, the neurological function score and escape latency (EL) were significantly increased (P<0.01), the times of crossing the original platform were decreased (P<0.01), the number of neurons in the CA1 area of the hippocampus was reduced, with incomplete morphology, widened synaptic gaps and significantly decreased PSD thickness (P<0.01), the positive expressions of BDNF, PSD-95, SYN and the protein expression levels of BDNF, TRKB, CREB, PSD-95, SYN were significantly decreased (P<0.01) in the model group. Compared with the model group, the neurological function scores and EL on the 12th and 13th day were decreased (P<0.01, P<0.05), the times of crossing the original platform were increased (P<0.01), the morphology of hippocampal CA1 neurons improved, the synaptic gaps was decreased (P<0.01), the PSD thickness was significantly increased (P<0.01), the positive expressions of BDNF, PSD-95, SYN, and the protein expression levels of BDNF, TRKB, CREB, PSD-95, SYN were increased (P<0.05, P<0.01) in the EA group. EA can alleviate cognitive impairment in IR rats, which may be related to its function in up-regulating the proteins of BDNF/TRKB/CREB pathway, promoting the expressions of synaptic plasticity marker proteins PSD-95 and SYN, thus improving the synaptic plasticity.

Effects and mechanisms of salidroside on the behavior of SPS-induced PTSD rats

Post-traumatic stress disorder (PTSD) is a complex mental disorder, closely associated with stress and traumatic events. Salidroside (Sal) has been reported to possess neuroprotective effects. However, the behavioral effects and mechanisms of Sal on PTSD remain unknown. In this study, we utilized a rat model of PTSD induced by single prolonged stress (SPS) and administered Sal intraperitoneally (25, 50, 75 mg/kg/d) for 14 days. We then examined the behavioral effects and underlying mechanisms of Sal on SPS-induced PTSD rats. Our findings demonstrated that Sal alleviated anxiety-like behavior and spatial learning and memory impairment in SPS-induced PTSD rats. Furthermore, Sal treatment preserved the histomorphology of the hippocampal region. It was observed that Sal protected against hippocampal neuronal apoptosis in PTSD rats by reducing the number of TUNEL-positive cells and modulating apoptosis-related proteins (Bcl-2 and Bax). Additionally, Sal inhibited the activation of the NF-κB/iNOS/COX-2 signaling pathway in the hippocampus of PTSD rats, thereby suppressing the release of inflammatory factors (TNF-α and IL-1β) and the activation of microglia. Notably, Sal increased the expression of synapse-associated proteins PSD95 and Synapsin I in the hippocampus, while also enhancing dendritic density in the region. In conclusion, our results demonstrated that Sal could attenuate SPS-induced PTSD-like behaviors by inhibiting hippocampal neuronal apoptosis, enhancing hippocampal synaptic plasticity, and reducing neuroinflammatory responses. These findings may provide a foundation for the potential clinical application of Sal in the treatment of PTSD.

Effects of Gryllus bimaculatus and Oxya chinensis sinuosa extracts on brain damage via blood-brain barrier control and apoptosis in mice with pentylenetetrazol-induced epilepsy.

The demand for environmentally friendly foods with high nutritional value and low carbon emissions is increasing with the aging of the global population and the crisis of food resources. Edible insects are becoming increasingly well-known as such foods. This study evaluated the effects and mechanisms of Gryllus bimaculatus (Cricket) (Gb) and Oxya chinensis sinuosa (Grasshopper) (Ocs) extracts on epilepsy. A pentylenetetrazol (PTZ)-induced seizure mouse model was used for the study, and Gb and Ocs extracts were administered for 29 days on alternate days at concentrations of 8 g/kg and 16 g/kg. The integrity of the blood-brain barrier (BBB) and brain edema was measured using the perfusion of Evans blue dye and brain water content. Gb and Ocs extracts prevented BBB permeabilization and cerebral edema through increasing the expression of tight junction-associated proteins in the endothelial cells and reducing water content in PTZ-treated mice. Additionally, Gb and Ocs extracts protected neurons from oxidative stress and apoptosis in different brain areas. These protective effects were demonstrated through the restoration of the expression of neuronal nuclear protein and postsynaptic density protein-95, thus increasing the levels of glutathione and superoxide dismutase, decreasing lipid peroxidation, and recovering apoptosis-associated proteins, such as Bax, cleaved PARP, and cleaved caspase-3, in epileptic mice. In addition, Gb and Ocs extracts rescued PTZ-induced hyperexcitable neurons to control mice level, as supported by the restored expression of gamma-aminobutyric acid (GABA) transporter 1, the metabotropic glutamate receptors-GRM2/3, and BDNF. This study suggested that Gb and Ocs extracts are novel medicinal candidates that can help ameliorate epilepsy by improving BBB health and preventing oxidative stress-mediated apoptosis.

Polysaccharides from Polygonatum cyrtonema Hua prevent post-traumatic stress disorder behaviors in mice: Mechanisms from the perspective of synaptic injury, oxidative stress, and neuroinflammation

Ethnopharmacological relevanceAccording to traditional Chinese medicine (TCM) theory, post-traumatic stress disorder (PTSD) is a kind of depression syndrome, and its occurrence is related to deficiencies of the heart and kidney. Polygonatum cyrtonema Hua replenishes Qi and blood and tonifies the five zang organs, so it is widely used in TCM as a prescription for the treatment of depression syndrome. The polysaccharides in P. cyrtonema Hua (PSP) are the main active components of the herb, but the effects of PSP on PTSD and the mechanisms remain unclear. Aim of the studyTo investigate the preventive effect of PSP on PTSD-like behaviors and to determine the mechanisms. MethodsWe used behavioral tests to evaluate PTSD-like behaviors in mice. Synaptic changes were assessed by transmission electron microscopy. Hematoxylin-eosin staining was used to assess pathological changes to the hippocampus, and immunofluorescence staining was used to observe changes in astrocytes. Serum corticosterone (CORT), cytokine, and hippocampal oxidation-related indicator levels were evaluated by ELISA. We detected the expression levels of synaptic, oxidative, and inflammation-related proteins in the hippocampus by western blotting. ResultsSingle prolonged stress (SPS)-modeled mice exhibited significant PTSD-like phenotypes, including increased fear memory acquisition and anxiety-like behaviors. These behavioral changes were prevented by PSP administration. Compared to controls, SPS modeling increased serum CORT, cytokine, and hippocampal malondialdehyde levels; decreased superoxide dismutase activity; and caused losses in pyramidal neurons, astrocytes, and synapses in the CA1 region. At the molecular level, the expression of brain-derived neurotrophic factor, postsynaptic density protein 95, nuclear factor erythroid 2-related factor 2 (Nrf2), phospho-tyrosine kinase receptor B, activity-regulated cytoskeleton-associated protein, heme oxygenase-1 (HO-1), and GluA1 decreased in SPS mice compared with the control group, while the expression of NOD-like receptor protein 3 (NLRP3), GluN2B, and apoptosis-associated speck-like protein increased in SPS mice. Treatment with PSP counteracted these abnormal changes. Importantly, ML385, an Nrf2 inhibitor, blocked PSP's ability to ameliorate PTSD behaviors and abnormal protein expression. The NLRP3 inhibitor MCC950 reduced the PTSD-like behaviors and normalized protein expression in SPS mice. ConclusionPSP prevents SPS-induced PTSD-like behaviors and synaptic damage by regulating oxidative stress and NLRP3-mediated inflammation, probably in an Nrf2/HO-1 signaling pathway-dependent manner.

Fecal microbiota transplantation inhibited neuroinflammation of traumatic brain injury in mice via regulating the gut-brain axis.

Recent studies have highlighted the vital role of gut microbiota in traumatic brain injury (TBI). Fecal microbiota transplantation (FMT) is an effective means of regulating the microbiota-gut-brain axis, while the beneficial effect and potential mechanisms of FMT against TBI remain unclear. Here, we elucidated the anti-neuroinflammatory effect and possible mechanism of FMT against TBI in mice via regulating the microbiota-gut-brain axis. The TBI mouse model was established by heavy object falling impact and then treated with FMT. The neurological deficits, neuropathological change, synaptic damage, microglia activation, and neuroinflammatory cytokine production were assessed, and the intestinal pathological change and gut microbiota composition were also evaluated. Moreover, the population of Treg cells in the spleen was measured. Our results showed that FMT treatment significantly alleviated neurological deficits and neuropathological changes and improved synaptic damage by increasing the levels of the synaptic plasticity-related protein such as postsynaptic density protein 95 (PSD-95) and synapsin I in the TBI mice model. Moreover, FMT could inhibit the activation of microglia and reduce the production of the inflammatory cytokine TNF-α, alleviating the inflammatory response of TBI mice. Meanwhile, FMT treatment could attenuate intestinal histopathologic changes and gut microbiota dysbiosis and increase the Treg cell population in TBI mice. These findings elucidated that FMT treatment effectively suppressed the TBI-induced neuroinflammation via regulating the gut microbiota-gut-brain axis, and its mechanism was involved in the regulation of peripheral immune cells, which implied a novel strategy against TBI.

Chronic Ambient Ozone Exposure Aggravates Autism-Like Symptoms in a Susceptible Mouse Model.

Although there is evidence that exposure to ground-level ozone (O3) may cause an increased risk of neurological disorders (e.g., autistic spectrum disorder), low-dose chronic ozone exposure and its adverse effects on the nervous system have not been fully understood. Here, we evaluated the potential neurotoxic effects of long-term exposure to environmentally relevant O3 concentration (200 μg/m3 via a whole-body inhalation system, 12 h/day for 5 days/week) using a susceptible mouse model of autism induced by valproic acid. Various indicators of oxidative stress, mitochondria, and synapse in the brain tissues were then measured to determine the overall damage of O3 to the mouse brain. The results showed an aggravated risk of autism in mice offspring, which was embodied in decreased antioxidant contents, disturbed energy generation in mitochondria, as well as reduced expressions of protein kinase Mζ (PKMζ) and synaptic proteins [e.g., Synapsin 1 (SYN 1), postsynaptic density protein-95 (PSD-95)]. Overall, our study indicates that prenatal exposure to environmentally relevant O3 may exacerbate the symptoms of autism, shedding light on possible molecular mechanisms and providing valuable insights into the pathogenesis of autism, especially concerning low-dose levels of those pollutants.

N-palmitoylethanolamine modulates hippocampal neuroplasticity in rats with stress-induced depressive behavior phenotype

Bioactive lipid mediator N-palmitoylethanolamide (PEA) is an endocannabinoid-like molecule. Based on our previous data, this study aimed to further investigate the antidepressant property of PEA via the peroxisome proliferator-activated receptor alpha (PPARα) pathway, focusing on the intervention of PEA on hippocampal neuroplasticity. Behavioral tests were performed in rats induced by unpredictable chronic mild stress (uCMS) in the last week of the experiment, and then the brain tissue samples were retained for subsequent immunohistochemical detection and Western blot analysis. In vitro, the apoptosis of HT22 cells induced by CORT and apoptosis-related proteins were detected by Hoechst staining and Western blot, respectively. The results showed that PEA ameliorated the depression-like phenotype in rats induced by uCMS, prevented the uCMS-induced reduction in the number of BrdU-positive cells, and increased BrdU/NeuN co-localization in the hippocampus, and upregulated the levels of synapse associated protein NCAM, MAP2, SYN and PSD95 in the hippocampus. Hoechst staining results showed that PEA significantly increased the CORT-induced reduction in the number of hippocampal neurons. Western blot analysis showed that PEA decreased the expression of caspase-3 and c-caspase-3, and increased the ratio of Bcl-2/Bax in CORT-induced HT22 cells. MK886, a PPARα antagonist, partially or completely reversed these effects. In conclusion, the therapeutic potential of PEA for depressive mood disorders may be through targeting the hippocampal neuroplasticity, including increasing adult neurogenesis and synaptic plasticity, as well as down-regulated neuronal apoptosis, to remodel hippocampal circuitries upon functional integration and PPARα pathway may be involved in this process.

Integrating Network Pharmacology and Component Analysis to Study the Potential Mechanisms of Qi-Fu-Yin Decoction in Treating Alzheimer's Disease.

To elucidate the potential mechanisms of QFY for the treatment of Alzheimer's Disease (AD), and explore the effective substances of QFY. UPLC-LTQ-Orbitrap-MS was used to identify the chemical constituents of the serum samples and the cerebrospinal fluid samples of rats after QFY administration. Network pharmacology was used to predict potential targets and pathways of QFY against AD. The AD mice model was established by subcutaneous injection of D-gal for 8 consecutive weeks. New object recognition (NOR) and Morris water maze test (MWM) were used to evaluate the learning and memory abilities of mice. Moreover, the levels of TNF-α, IL-1β, and IL-18 in the brain hippocampus of mice were determined by ELISA. The expression of Bax, Bcl-2, Caspase-1, PSD95, SYP, ICAM-1 and MCP-1 proteins in the hippocampus was detected by Western blotting. Furthermore, qRT-PCR was used to detect the gene expressions of PSD95, SYP, M1 and M2 polarization markers of microglia, including iNOS, CD16, ARG-1, and IL-10 in the hippocampus. A total of 51 prototype compounds were detected in rat serum and 15 prototype components were identified in rat cerebrospinal fluid. Behavioral experiments revealed that QFY significantly increased the recognition index, decreased the escape latency, increased the platform crossing times and increased the residence time in the target quadrant. QFY also could alleviate the ultrastructural pathological changes in the hippocampus of AD mice. Meanwhile, QFY treatment suppressed the expression of inflammatory factors, such as TNF-α, IL-1β, and IL-18. QFY improved the synaptic plasticity of the hippocampus in D-gal model mice by significantly increasing the expression of proteins and mRNAs of PSD95 and SYP. QFY could effectively improve the learning and memory impairment of D-gal-induced AD mice by inhibiting the excessive activation of microglia, enhancing the expression of M2 microglia, inhibiting the increase of inflammatory factors, cell adhesion factors and chemokines, anti-apoptosis, and improving synaptic plasticity.

Melatonin Yaşlı Sıçanlarda Postoperatif Kognitif Disfonksiyonu İyileştirir: Oksidatif Stres, PSD95 ve Ca2+/Kalmodulin Bağımlı Protein Kinazın Önemi

Aim: Postoperative cognitive dysfunction (POCD) is usually seen in the aged patients in postoperative&#x0D; period. In the present study, we aimed to investigate the effects of melatonin on cognitive and synaptic&#x0D; dysfunction and oxidative stress in POCD model constructed by abdominal surgery in aged rats.&#x0D; Material and Methods: Twenty months old male Wistar rats were randomly allocated into the control&#x0D; group, melatonin treated-control group, surgery group and melatonin treated-surgery group. The novel&#x0D; object recognition test (NORT) was used to assess the postoperative cognitive ability of rats at the&#x0D; end of the experiments. The contents of malondialdehyde (MDA) and reduced glutathione (GSH) were&#x0D; evaluated in the synaptosomes of hippocampus by spectrophotometric methods. The protein levels of&#x0D; calcium-calmodulin dependent protein kinase II (CaMKII) and postsynaptic density protein 95 (PSD95)&#x0D; were measured by using ELISA. .&#x0D; Results: Animals in surgery group showed significant an impairment of novel object recognition memory&#x0D; in NORT. Surgery group also exhibited increased content of MDA (21.05±3.96) and decreased levels&#x0D; of GSH (5.86±0.26) and PSD95 (156.04±2.56) in the hippocampus (respectively p=0.012, p