Expression Of Postsynaptic Density Protein Research Articles

Positive Effect of 6-Gingerol on Functional Plasticity of Microglia in a rat Model of LPS-induced Depression.

Neuroinflammation has emerged as a crucial factor in the development of depression. Despite the well-known anti-inflammatory properties of 6-gingerol, its potential impact on depression remains poorly understood. This study aimed to investigate the antidepressant effects of 6-gingerol by suppressing microglial activation. In vivo experiments were conducted to evaluate the effect of 6-gingerol on lipopolysaccharide (LPS)-induced behavioral changes and neuroinflammation in rat models. In vitro studies were performed to examine the neuroprotective properties of 6-gingerol against LPS-induced microglial activation. Furthermore, a co-culture system of microglia and neurons was established to assess the influence of 6-gingerol on the expression of synaptic-related proteins, namely synaptophysin (SYP) and postsynaptic density protein 95 (PSD95), which are influenced by microglial activation. In the in vivo experiments, administration of 6-gingerol effectively alleviated LPS-induced depressive behavior in rats. Moreover, it markedly suppressed the activation of rat prefrontal cortex (PFC) microglia induced by LPS and the activation of the NF-κB/NLRP3 inflammatory pathway, while also reducing the levels of inflammatory cytokines IL-1β and IL-18. In the in vitro experiments, 6-gingerol mitigated nuclear translocation of NF-κB p65, NLRP3 activation, and maturation of IL-1β and IL-18, all of which were induced by LPS. Furthermore, in the co-culture system of microglia and neurons, 6-gingerol effectively restored the decreased expression of SYP and PSD95. The findings of this study demonstrate the neuroprotective effects of 6-gingerol in the context of LPS-induced depression-like behavior. These effects are attributed to the inhibition of microglial hyperactivation through the suppression of the NF-κB/NLRP3 inflammatory pathway.

Mechanism Explanation on Improved Cognitive Ability of D-Gal Inducing Aged Mice Model by Lactiplantibacillus plantarum MWFLp-182 via the Microbiota-Gut-Brain Axis.

Gut microbiota can influence cognitive ability via the gut-brain axis. Lactiplantibacillus plantarum MWFLp-182 (L. plantarum MWFLp-182) was obtained from feces of long-living individuals and could exert marked antioxidant ability. Interestingly, this strain reduced the D-galactose-induced impaired cognitive ability in BALB/c mice. To comprehensively elucidate the underlying mechanism, we evaluated the colonization, antioxidant, and anti-inflammatory activities of L. plantarum MWFLp-182, along with the expression of potential genes associated with cognitive ability influenced and gut microbiota. L. plantarum MWFLp-182 enhanced the expression of anti-inflammatory cytokines, reduced the expression of proinflammatory cytokines, and increased tight junction protein expression in the colon. Moreover, L. plantarum MWFLp-182 could modify the gut microbiota. Notably, treatment with L. plantarum MWFLp-182 upregulated the expression of postsynaptic density protein-95, nuclear factor erythroid 2-related factor, nerve growth factor, superoxide dismutase, and brain-derived neurotrophic factor/neuronal nuclei, while downregulating the expression of bcl-2-associated X and malondialdehyde in the hippocampus and upregulating short-chain fatty acids against D-galactose-induced mouse brain deficits. Accordingly, L. plantarum MWFLp-182 could improve cognitive ability in a D-galactose-inducing mouse model.

Repetitive transcranial magnetic stimulation via the hippocampal brain-derived neurotrophic factor-tyrosine kinase receptor B pathway to affect sexual behavior and neuroplasticity in rapid ejaculation rats.

Premature ejaculation (PE) is the most prevalent sexual dysfunction among men. Eejaculation involves a complex nervous mechanism in which the ejaculatory centers play a key role in modulating sperm emission. Although treatment possibilities span from psychotherapy to pharmacological approaches, results show inconsistent efficacy. In this context, the emergence of repetitive transcranial magnetic stimulation (rTMS) as a non-invasive neuromodulatory approach represents a compelling avenue for potential therapeutic exploration. To investigate whether high-frequency transcranial magnetic stimulation can modulate the ejaculatory behavior of rats with rapid ejaculation by altering neurotransmitter levels and neuroplasticity in the hippocampus. Rats have been screened for rapid ejaculation by observing behavioral indices of mating, and subsequently divided into two groups. The intervention group was administered with a 10Hz rTMS stimulation, whereas the control group received a sham procedure. Upon the delivery of rTMS, we investigated ejaculation latency (EL), the hippocampal 5-hydroxytryptamine (5-HT) concentration, brain-derived neurotrophic factor (BDNF), synaptophysin (SYN), and postsynaptic density protein 95 (PSD95) expressions, as well as BDNF-receptor tyrosine kinase receptor B (TrkB) pathway upregulation. After 14 days, EL was increased in the intervention group compared with the control group. 5-HT concentration in the hippocampal region was increased, and high-frequency rTMS activated the BDNF and TrkB pathways, including phosphorylation of cAMP response element-binding protein (CREB), and upregulated the transcription and protein expression of SYN, and PSD95. RTMS upregulates BDNF, SYN, and PSD95 expression through activation of the BDNF-TrkB pathway and increases brain 5-hydroxytryptamine thereby regulating neuroplasticity and improving ejaculation.

A106: Aerobic Exercise Modulates GPCR/cAMP/PKA Signaling Pathway and Complement-Microglia Axis to Prevent Synaptic Loss in APP/PS1 Mice

Purpose: Synaptic failure serves as a primary contributor to memory dysfunction in Alzheimer's disease (AD). Physical exercise has demonstrated the potential to thwart and delay degenerative alterations in memory functions linked to AD. Investigating the underlying mechanisms may unveil crucial insights into early pathological changes, offering breakthroughs for both understanding and treating AD. Methods: We utilized 3-month-old APP/PS1 mice and subjected them to a 12-week aerobic exercise intervention. The spatial learning and memory functions of the mice were assessed using the Morris water maze test, while Golgi staining was employed to determine dendritic spine density in each mouse group. To analyze the potential mechanisms mediating the effects of exercise intervention in the AD brain, we conducted RNA sequencing. Subsequently, pathway enrichment analysis, immunofluorescence, real-time quantitative PCR, and western blotting were employed to elucidate the impact of regular aerobic exercise on the GPCR/cAMP/PKA signaling pathway and complement-microglia axis. Results: Our findings reveal that a 12-week aerobic exercise intervention significantly enhanced spatial learning and memory function in APP/PS1 mice. Moreover, it led to a substantial increase in dendritic spine density and elevated expression of postsynaptic density protein 95 (PSD-95) in the cortex and hippocampus. Aerobic exercise demonstrated the ability to improve the expression of certain genes and enhance synaptic pathways in the brains of APP/PS1 mice. This suggests that aerobic exercise facilitates synaptic growth in APP/PS1 mice by modulating G protein-coupled receptors (GPCRs) and activating the cAMP signaling pathway, with significant alterations observed in the expressions of Hcar1 and Vipr2 genes. Furthermore, exercise intervention resulted in the significant down-regulation (P < 0.05 or P < 0.01) of cAMP, p-PKA/PKA, GluA1, and CaMKII protein expressions in the brain tissue of APP/PS1 mice, which were subsequently up-regulated after exercise (P < 0.01). Notably, regular aerobic exercise effectively suppressed the activation of IBA-1+ microglia cells (P < 0.01), reversed changes in M1 phenotype markers (Cd86 and iNOS) and M2 phenotype markers (Arg-1) of microglia cells (P < 0.05), reduced the production of promoters C1q and central factor C3 in the macrosomatic cascade (P < 0.05), and prevented the colocalization of microglia and PSD-95 (P < 0.01). Conclusion: In conclusion, our results indicate that physical exercise plays a pivotal role in fostering early synaptic growth and averting synaptic loss in Alzheimer's disease (AD). This effect may be attributed to the regulation of the G protein-coupled receptors (GPCRs)/cAMP/PKA signaling pathway and the suppression of complement-mediated microglial phagocytosis of synapses. This mechanistic insight underscores the inherent contribution of exercise to health promotion, offering potential avenues for synaptic-focused interventions in the early stages of AD treatment.

The polysaccharides from the fruits of Lycium barbarum ameliorate high-fat and high-fructose diet-induced cognitive impairment via regulating blood glucose and mediating gut microbiota

High-fat and high-fructose diet (HFFD) consumption can induce cognitive dysfunction and gut microbiota disorder. In the present study, the effects of the polysaccharides from the fruits of Lycium barbarum L. (LBPs) on HFFD-induced cognitive deficits and gut microbiota dysbiosis were investigated. The results showed that intervention of LBPs (200 mg/kg/day) for 14 weeks could significantly prevent learning and memory deficits in HFFD-fed mice, evidenced by a reduction of latency and increment of crossing parameters of platform quadrant in Morris water maze test. Moreover, oral administration of LBPs enhanced the expression of postsynaptic density protein 95 and brain-derived neurotrophic factor and reduced the activation of glial cells in hippocampus. Besides, LBPs treatment enriched the relative abundances of Allobaculum and Lactococcus and reduced the relative abundance of Proteobacteria in gut bacterial community of HFFD-fed mice, accompanied by increased levels of short-chain fatty acids (SCFAs) as well as expression of associated G protein-coupled receptors. Furthermore, LBPs intervention prevented insulin resistance, obesity and colonic inflammation. Finally, a significant correlation was observed among neuroinflammation associated parameters, gut microbiota and SCFAs through Pearson correlation analysis. Collectively, these findings suggested that the regulation of gut microbiota might be the potential mechanism of LBPs on preventing cognitive dysfunction induced by HFFD.

Stauntonia chinensis injection relieves neuropathic pain by increasing the expression of PSD-95 and reducing the proliferation of phagocytic microglia.

Neuroinflammation induced by engulfment of synapses by phagocytic microglia plays a crucial role in neuropathic pain. Stauntonia chinensis is extracted from Stauntonia chinensis DC, which has been used as a traditional Chinese medicine to control trigeminal neuralgia or sciatica. However, the specific anti-neuralgia mechanism of Stauntonia chinensis is unknown. In this study, the analgesic effect of Stauntonia chinensis injection (SCI) in mice with neuropathic pain and the possible mechanisms are explored. We find that a local injection of 0.1 mL Stauntonia chinensis for 14 days can considerably relieve mechanical hyperalgesia and thermal hyperalgesia in mice with sciatic chronic constriction injury (CCI). Immunofluorescence staining shows that SCI reduces neuroinflammation in the spinal cord of CCI mice. RNA sequencing reveals that the expression of postsynaptic density protein 95 (PSD-95), a postsynaptic scaffold protein, is downregulated in the spinal cord of CCI mice, but upregulated after SCI administration. Immunofluorescence experiments also demonstrate that SCI administration reverses microglia proliferation and PSD-95 downregulation in CCI mice. These data suggest that SCI relieves neuropathic pain by increasing the expression of PSD-95 and reducing the proliferation of phagocytic microglia.

β-asarone improves cognitive impairment and alleviates autophagy in mice with vascular dementia via the cAMP/PKA/CREB pathway

BackgroundVascular dementia (VD) is the second most common type of dementia after Alzheimer's disease. β-asarone, a major component of Acorus tatarinowii Schott, is important in neurodegenerative and neurovascular diseases. Studies have confirmed that β-asarone can mitigate autophagy and reduce damage in hypoxic cells. We also reported that β-asarone improves learning and memory. This study further clarifies whether β-asarone attenuates cerebral ischaemic injury by acting through the cAMP/PKA/CREB pathway in VD model mice. MethodsHere, genes and potential pathways that may be targeted by β-asarone for the treatment of transient cerebral ischaemia (TCI) and cognitive impairment (CI) were obtained using network pharmacology. The two-vessel occlusion method was used to establish the VD model. The Morris water maze test was used to evaluate the effects on memory. Then, the protein levels of mitofusin-2 (Mfn2), brain-derived neurotrophic factor (BDNF), optic atrophy 1 (OPA1), cyclic adenosine monophosphate (cAMP), myelin basic protein (MBP), matrix metalloproteinase-9 (MMP9) and neuron specific enolase (NSE) were determined by ELISA. The levels of superoxide dismutase (SOD) and malonaldehyde (MDA) were measured using commercial kits. Then, qRT-PCR was employed to investigate the expression of the candidate genes screened from the protein-protein interaction (PPI) network. Furthermore, the expression of the autophagy-related proteins Beclin-1, (microtubule-associated protein light chain 3) LC3, p62, postsynaptic density protein 95 (PSD95), protein kinase A (PKA), pPKA, cyclic-AMP response binding protein (CREB), and pCREB was determined by western blotting. The expression of autophagy-related proteins, PSD95 and translocase of outer mitochondrial membrane 20 (TOM20) was determined by immunofluorescence analyses. ResultsThe network pharmacological analysis showed 234 targets related to β-asarone, 1,118 genes related to TCI and 2,039 genes associated with CI. Our results confirm that β-asarone treatment not only alleviated brain damage in the VD model by improving mitochondrial and synaptic function, reducing neuronal injury and upregulating the expression of antioxidants but also effectively improved the cognitive behaviour of VD model mice. Moreover, β-asarone downregulated VD-induced RELA and CCND1 mRNA expression. In addition, we validated that β-asarone increased the phosphorylation of PKA and CREB and upregulated cAMP protein expression. The results showed that the cAMP/PKA/CREB signalling pathway was upregulated. Moreover, β-asarone administration decreased the protein expression levels of Beclin-1 and LC3 and increased the expression levels of p62 in VD model mice. Conclusionsβ-asarone inhibits Beclin-1-dependent autophagy and upregulates the cAMP/PKA/CREB signalling pathway to attenuate mitochondrial and synaptic damage from cerebral ischaemia and improve learning and cognitive abilities in VD model mice.

Hydrogen sulfide attenuates depression-like behaviours in Parkinson's disease model rats by improving synaptic plasticity in a hippocampal Warburg effect-dependent manner

BackgroundDepression is a highly prevalent comorbidity arising in patients with Parkinson's disease (PD). However, depression in patients with PD is poorly treated. Hydrogen sulfide (H2S), a neuromodulator, has the potential to relieve depression. ObjectiveTo investigate whether H2S attenuates depression-like behaviours in a rat model of PD and examine the underlying mechanisms. MethodsWe utilised rotenone to develop a PD model with subcutaneous injections in the dorsal cervical region of Sprague-Dawley rats. The depression-like behaviours in the rotenone-induced PD model rats were assessed through forced swimming, tail suspension, open field, novelty-suppressed feeding, and elevated plus-maze tests. The expression of postsynaptic density protein-95 and synapsin-1, related to synaptic plasticity, was detected using Western blot in the hippocampus. The hippocampal ultrastructure, including the synaptic density, length of the synaptic active zone, postsynaptic density thickness, and synaptic gap width, was detected using transmission electron microscopy. ResultsWe proved that sodium hydrosulfide (NaHS; a donor of H2S) significantly attenuated the depression-like behaviours and disorders of hippocampal synaptic plasticity in rotenone-induced PD rats. Furthermore, inhibition of the hippocampal Warburg effect by 2-deoxyglucose abolished NaHS-enhanced hippocampal synaptic plasticity and reversed NaHS-attenuated depression-like behaviours in the rotenone-induced PD rats. ConclusionH2S attenuates PD-associated depression by improving the hippocampal synaptic plasticity in a hippocampal Warburg effect-dependent manner.

Neuroprotective effect and mechanism of Zuogui Jiangtang Jieyu Formula on diabetes mellitus complicated with depression model rats based on CX3CL1-CX3CR1 axis

Based on the CX3C chemokine ligand 1(CX3CL1)-CX3C chemokine receptor 1(CX3CR1) axis, this study explored the potential mechanism by which Zuogui Jiangtang Jieyu Formula(ZGJTJY) improved neuroinflammation and enhanced neuroprotective effect in a rat model of diabetes mellitus complicated with depression(DD). The DD rat model was established by feeding a high-fat diet combined with streptozotocin(STZ) intraperitoneal injection for four weeks and chronic unpredictable mild stress(CUMS) combined with isolated cage rearing for five weeks. The rats were divided into a control group, a model group, a positive control group, an inhibitor group, and a ZGJTJY group. The open field test and forced swimming test were used to assess the depression-like behaviors of the rats. Enzyme-linked immunosorbent assay(ELISA) was performed to measure the expression levels of the pro-inflammatory cytokines interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) in plasma. Immunofluorescence staining was used to detect the expression of ionized calcium-binding adapter molecule 1(Iba1), postsynaptic density protein-95(PSD95), and synapsin-1(SYN1) in the hippocampus. Hematoxylin-eosin(HE) staining, Nissl staining, and TdT-mediated dUTP nick end labeling(TUNEL) fluorescence staining were performed to assess hippocampal neuronal damage. Western blot was used to measure the expression levels of CX3CL1, CX3CR1, A2A adenosine receptor(A2AR), glutamate receptor 2A(NR2A), glutamate receptor 2B(NR2B), and brain-derived neurotrophic factor(BDNF) in the hippocampus. Compared with the model group, the ZGJTJY group showed improved depression-like behaviors in DD rats, enhanced neuroprotective effect, increased expression of PSD95, SYN1, and BDNF(P<0.01), and decreased expression of Iba1, IL-1β, and TNF-α(P<0.01), as well as the expression of CX3CL1, CX3CR1, A2AR, NR2A, and NR2B(P<0.01). These results suggest that ZGJTJY may exert its neuroprotective effect by inhibiting the CX3CL1-CX3CR1 axis and activation of hippocampal microglia, thereby improving neuroinflammation and abnormal activation of N-methyl-D-aspartate receptor(NMDAR) subunits, and ultimately enhancing the expression of synaptic-related proteins PSD95, SYN1, and BDNF in the hippocampus.

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.

Chinese Tuina remodels the synaptic structure in neuropathic pain rats by downregulating the expression of N-methyl D-aspartate receptor subtype 2B and postsynaptic density protein-95 in the spinal cord dorsal horn.

To investigate whether the Chinese massage system, Tuina, exerts analgesic effects in a rat model of chronic constriction injury (CCI) by remodeling the synaptic structure in the spinal cord dorsal horn (SCDH). Sixty-nine male Sprague-Dawley rats were randomly and evenly divided into the normal group, sham group, CCI group, CCI + Tuina group, CCI + MK-801 [an -methyl D-aspartate receptor subtype 2B (NR2B) antagonist] group, and CCI + MK-801 + Tuina group. The neuropathic pain model was established using CCI with right sciatic nerve ligation. Tuina was administered 4 d after CCI surgery, using pressing manipulation for 10 min, once daily. Motor function was observed with the inclined plate test, and pain behaviors were observed by the Von Frey test and acetone spray test. At 19 d after surgery, the L3-L5 spinal cord segments were removed. Glutamate, interleukin 1β (IL-1β), and tumor necrosis factor-α (TNF-α) levels were detected by enzyme-linked immunosorbent assay. The protein expression levels of NR2B and postsynaptic density protein-95 (PSD-95) were detected by Western blot, and the synaptic structure was observed by transmission electron microscopy (TEM). CCI reduced motor function and caused mechanical and cold allodynia in rats, increased glutamate concentration and TNF-α and IL-1β levels, and increased expression of synapse-related proteins NR2B and PSD-95 in the SCDH. TEM revealed that the synaptic structure of SCDH neurons was altered. Most of these disease-induced changes were reversed by Tuina and intrathecal injection of MK-801 ( < 0.05 or < 0.01). For the majority of experiments, no significant differences were found between the CCI + MK-801 and CCI + MK-801 + Tuina groups. Chinese Tuina can alleviate pain by remodeling the synaptic structure, and NR2B and PSD-95 receptors in the SCDH may be among its targets.

Reducing complement activation during sleep deprivation yields cognitive improvement by dexmedetomidine

BackgroundSleep loss and its associated conditions (e.g. cognitive deficits) represent a large societal burden, but the underlying mechanisms of these cognitive deficits remain unknown. This study assessed the effect of dexmedetomidine (DEX) on cognitive decline induced by sleep loss. MethodsC57BL/6 mice were subjected to chronic sleep restriction (CSR) for 20 h (5 pm–1 pm the next day) daily for 7 days, and cognitive tests were subsequently carried out. The neuromolecular and cellular changes that occurred in the presence and absence of DEX (100 μg kg−1, i.v., at 1 pm and 3 pm every day) were also investigated. ResultsCSR mice displayed a decline in learning and memory by 12% (P<0.05) in the Y-maze and by 18% (P<0.01) in the novel object recognition test; these changes were associated with increases in microglial activation, CD68+ microglial phagosome counts, astrocyte-derived complement C3 secretion, and microglial C3a receptor expression (all P<0.05). Synapse elimination, as indicated by a 66% decrease in synaptophysin expression (P=0.0004) and a 45% decrease in postsynaptic density protein-95 expression (P=0.0003), was associated with the occurrence of cognitive deficits. DEX activated astrocytic α2A adrenoceptors and inhibited astrocytic complement C3 release to attenuate synapse elimination through microglial phagocytosis. DEX restored synaptic connections and reversed cognitive deficits induced by CSR. ConclusionsThe results demonstrate that complement pathway activation associated with synapse elimination contributes to sleep loss-related cognitive deficits and that dexmedetomidine protects against sleep deprivation-induced complement activation. Dexmedetomidine holds potential for preventing cognitive deficits associated with sleep loss, which warrants further study.

Downregulation of Preso protects against ischemic/reperfusion-mediated neuronal injury through regulating PSD95-nNOS/YAP pathways

Cerebral ischemic/reperfusion (I/R) injury has become a great challenge harming patients’ life. This study aims to explore the regulatory role of Preso during cerebral I/R injury and to elucidate the potential mechanism. Here, we established a middle cerebral artery occlusion/reperfusion (MCAO/IR) rat model and an oxygen-glucose deprivation/reoxygenation (OGD/R)-mediated PC12 cell model to evaluate the expression and role of Preso following cerebral I/R injury. Histopathological injury and infarct size were assessed by hematoxylin and eosin (HE) and 2,3,5-Triphenyltertrazolium chloride (TTC) staining. Double immunofluorescence staining was performed to assess neuronal apoptosis in brain tissues. Cell counting kit-8 (CCK-8) and flow cytometry were performed to evaluate cell viability and apoptosis, respectively. The reactive oxygen species (ROS) and nitric oxide (NO) levels were detected using their respective detection kits, and the expression of corresponding proteins was examined adopting Western blot. The results showed that Preso was upregulated in OGD/R-induced PC12 cells and MCAO rats. Preso knockdown significantly reduced OGD/R-caused viability loss, apoptosis and oxidative stress in PC12 cells, and reduced infarct size, attenuated histological injury, and inhibited apoptosis and oxidative stress in the brain tissues from MCAO rats, as well as inhibiting the expression of postsynaptic density protein-95 (PSD95) and nitric oxide synthase (nNOS) and repressing YAP phosphorylation in vitro. In addition, the protective role of Preso knockdown against cerebral I/R injury was partly strengthened by IC87201, the nNOS/PSD95 interaction inhibitor, or weakened by Verteporfin (Vert), an inhibitor of YAP. In conclusion, Perso knockdown might exert a protective role against cerebral I/R injury via regulating PSD95-nNOS and YAP pathways, providing a potential therapeutic target for the treatment of ischemic stroke.

Activation of CB1R alleviates central sensitization by regulating HCN2-pNR2B signaling in a chronic migraine rat model

BackgroundCentral sensitization has been widely accepted as an underlying pathophysiological mechanism of chronic migraine (CM), activation of cannabinoid type-1 receptor (CB1R) exerts antinociceptive effects by relieving central sensitization in many pain models. However, the role of CB1R in the central sensitization of CM is still unclear.MethodsA CM model was established by infusing inflammatory soup (IS) into the dura of male Wistar rats for 7 days, and hyperalgesia was assessed by the mechanical and thermal thresholds. In the periaqueductal gray (PAG), the mRNA and protein levels of CB1R and hyperpolarization-activated cyclic nucleotide-gated cation channel 2 (HCN2) were measured by qRT–PCR and western blotting. After intraventricular injection of Noladin ether (NE) (a CB1R agonist), ZD 7288 (an HCN2 blocker), and AM 251 (a CB1R antagonist), the expression of tyrosine phosphorylation of N-methyl-D-aspartate receptor subtype 2B (pNR2B), calcium-calmodulin-dependent kinase II (CaMKII), and phosphorylated cAMP-responsive element binding protein (pCREB) was detected, and central sensitization was evaluated by the expression of calcitonin gene-related peptide (CGRP), c-Fos, and substance P (SP). Synaptic-associated protein (postsynaptic density protein 95 (PSD95) and synaptophysin (Syp)) and synaptic ultrastructure were detected to explore synaptic plasticity in central sensitization.ResultsWe observed that the mRNA and protein levels of CB1R and HCN2 were both significantly increased in the PAG of CM rats. The application of NE or ZD 7288 ameliorated IS-induced hyperalgesia; repressed the pNR2B/CaMKII/pCREB pathway; reduced CGRP, c-Fos, SP, PSD95, and Syp expression; and inhibited synaptic transmission. Strikingly, the application of ZD 7288 relieved AM 251-evoked elevation of pNR2B, CGRP, and c-Fos expression.ConclusionsThese data reveal that activation of CB1R alleviates central sensitization by regulating HCN2-pNR2B signaling in CM rats. The activation of CB1R might have a positive influence on the prevention of CM by mitigating central sensitization.

Antisense oligonucleotides targeting basal forebrain ATXN2 enhances spatial memory and ameliorates sleep deprivation-induced fear memory impairment in mice.

Regulation of brain-derived neurotrophic factor (BDNF) in the basal forebrain ameliorates sleep deprivation-induced fear memory impairments in rodents. Antisense oligonucleotides (ASOs) targeting ATXN2 was a potential therapy for spinocerebellar ataxia, whose pathogenic mechanism associates with reduced BDNF expression. We tested the hypothesis that ASO7 targeting ATXN2 could affect BDNF levels in mouse basal forebrain and ameliorate sleep deprivation-induced fear memory impairments. Adult male C57BL/6 mice were used to evaluate the effects of ASO7 targeting ATXN2 microinjected into the bilateral basal forebrain (1 μg, 0.5 μL, each side) on spatial memory, fear memory and sleep deprivation-induced fear memory impairments. Spatial memory and fear memory were detected by the Morris water maze and step-down inhibitory avoidance test, respectively. Immunohistochemistry, RT-PCR, and Western blot were used to evaluate the changes of levels of BDNF, ATXN2, and postsynaptic density 95 (PSD95) protein as well as ATXN2 mRNA. The morphological changes in neurons in the hippocampal CA1 region were detected by HE staining and Nissl staining. ASO7 targeting ATXN2 microinjected into the basal forebrain could suppress ATXN2 mRNA and protein expression for more than 1 month and enhance spatial memory but not fear memory in mice. BDNF mRNA and protein expression in basal forebrain and hippocampus was increased by ASO7. Moreover, PSD95 expression and synapse formation were increased in the hippocampus. Furthermore, ASO7 microinjected into the basal forebrain increased BDNF and PSD95 protein expression in the basal forebrain of sleep-deprived mice and counteracted sleep deprivation-induced fear memory impairments. ASOs targeting ATXN2 may provide effective interventions for sleep deprivation-induced cognitive impairments.

Different Alterations of Hippocampal and Reticulo-Thalamic GABAergic Parvalbumin-Expressing Interneurons Underlie Different States of Unconsciousness

We traced the changes in GABAergic parvalbumin (PV)-expressing interneurons of the hippocampus and reticulo-thalamic nucleus (RT) as possible underlying mechanisms of the different local cortical and hippocampal electroencephalographic (EEG) microstructures during the non-rapid-eye movement (NREM) sleep compared with anesthesia-induced unconsciousness by two anesthetics with different main mechanisms of action (ketamine/diazepam versus propofol). After 3 h of recording their sleep, the rats were divided into two experimental groups: one half received ketamine/diazepam anesthesia and the other half received propofol anesthesia. We simultaneously recorded the EEG of the motor cortex and hippocampus during sleep and during 1 h of surgical anesthesia. We performed immunohistochemistry and analyzed the PV and postsynaptic density protein 95 (PSD-95) expression. PV suppression in the hippocampus and at RT underlies the global theta amplitude attenuation and hippocampal gamma augmentation that is a unique feature of ketamine-induced versus propofol-induced unconsciousness and NREM sleep. While PV suppression resulted in an increase in hippocampal PSD-95 expression, there was no imbalance between inhibition and excitation during ketamine/diazepam anesthesia compared with propofol anesthesia in RT. This increased excitation could be a consequence of a lower GABA interneuronal activity and an additional mechanism underlying the unique local EEG microstructure in the hippocampus during ketamine/diazepam anesthesia.

Impact of the gut microbiome on nicotine's motivational effects and glial cells in the ventral tegmental area in male mice.

A link between gut dysbiosis and the pathogenesis of brain disorders has been identified. A role for gut bacteria in drug reward and addiction has been suggested but very few studies have investigated their impact on brain and behavioral responses to addictive drugs so far. In particular, their influence on nicotine's addiction-like processes remains unknown. In addition, evidence shows that glial cells shape the neuronal activity of the mesolimbic system but their regulation, within this system, by the gut microbiome is not established. We demonstrate that a lack of gut microbiota in male mice potentiates the nicotine-induced activation of sub-regions of the mesolimbic system. We further show that gut microbiota depletion enhances the response to nicotine of dopaminergic neurons of the posterior ventral tegmental area (pVTA), and alters nicotine's rewarding and aversive effects in an intra-VTA self-administration procedure. These effects were not associated with gross behavioral alterations and the nicotine withdrawal syndrome was not impacted. We further show that depletion of the gut microbiome modulates the glial cells of the mesolimbic system. Notably, it increases the number of astrocytes selectively in the pVTA, and the expression of postsynaptic density protein 95 in both VTA sub-regions, without altering the density of the astrocytic glutamatergic transporter GLT1. Finally, we identify several sub-populations of microglia in the VTA that differ between its anterior and posterior sub-parts, and show that they are re-organized in conditions of gut microbiota depletion. The present study paves the way for refining our understanding of the pathophysiology of nicotine addiction.

Moderate-Intensity Intermittent Training Alters the DNA Methylation Pattern of PDE4D Gene in Hippocampus to Improve the Ability of Spatial Learning and Memory in Aging Rats Reduced by D-Galactose

(1) Background: Aging is the main risk factor for most neurodegenerative diseases, and the inhibition of Phosphodiesterase 4(PDE4) is considered a potential target for the treatment of neurological diseases. The purpose of this study was to investigate the inhibitory effect of moderate-intensity intermittent training (MIIT) on PDE4 in the hippocampus of rats with D-galactose (D-gal)-induced cognitive impairment, and the possible mechanism of improving spatial learning and memory. (2) Methods: the aging rats were treated with D-Gal (150 mg/kg/day, for 6 weeks). The aging rats were treated with MIIT for exercise intervention (45 min/day, 5 days/week, for 8 weeks). The Morris water maze test was performed before and after MIIT to evaluate the spatial learning and memory ability, then to observe the synaptic ultrastructure of the hippocampus CA1 region, to detect the expression of synaptic-related protein synaptophysin (SYP) and postsynaptic density protein 95 (PSD95), and to detect the expression of PDE4 subtypes, cAMP, and its signal pathway protein kinase A (PKA)/cAMP response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF), and the PDE4 methylation level. (3) Results: we found that MIIT for 8 weeks alleviated the decline in spatial learning and memory ability, and improved the synaptic structure of the hippocampus and the expression of synaptic protein SYP and PSD95 in D-Gal aging rats. To elucidate the mechanism of MIIT, we analyzed the expression of PDE4 isoforms PDE4A/PDE4B/PDE4D, cAMP, and the signaling pathway PKA/CREB/BDNF, which play an important role in memory consolidation and maintenance. The results showed that 8 weeks of MIIT significantly up-regulated cAMP, PKA, p-CREB, and BDNF protein expression, and down-regulated PDE4D mRNA and protein expression. Methylation analysis of the PDE4D gene showed that several CG sites in the promoter and exon1 regions were significantly up-regulated. (4) Conclusions: MIIT can improve the synaptic structure of the hippocampus CA1 area and improve the spatial learning and memory ability of aging rats, which may be related to the specific regulation of the PDE4D gene methylation level and inhibition of PDE4D expression.

Endothelial progenitor cell transplantation attenuates synaptic loss associated with enhancing complement receptor 3-dependent microglial/macrophage phagocytosis in ischemic mice

Endothelial progenitor cell (EPC) transplantation has therapeutic effects in cerebral ischemia. However, how EPCs modulate microglial activity remains unclear. In the study, we explored whether EPCs modulated microglial/macrophage activity and facilitated injured brain repair. Adult male mice (n = 184) underwent transient middle cerebral artery occlusion, and EPCs were transplanted into the brain immediately after ischemia. Microglial/macrophage activity and complement receptor 3 (CR3) expression were evaluated in ischemic brains and cultured microglia. CR3 agonist leukadherin-1 was administrated into mice immediately after ischemia to imitate the effects of EPCs. Synaptophysin and postsynaptic density protein 95 (PSD-95) expressions were detected in EPC- and leukadherin-1 treated mice. We found that EPC transplantation increased the number of M2 microglia/macrophage-phagocytizing apoptotic cells and CR3 expression in ischemic brains at 3 days after ischemia (p < 0.05). EPC-conditional medium or cultured EPCs increased microglial migration and phagocytosis and upregulated CR3 expression in cultured microglia under oxygen-glucose deprivation condition (p < 0.05). Leukadherin-1 reduced brain atrophy volume and neurological deficits at 14 days after ischemia (p < 0.05). Both EPC transplantation and leukadherin-1 increased synaptophysin and PSD-95 expression at 14 days after ischemia (p < 0.05). EPC transplantation promoted CR3-mediated microglial/macrophage phagocytosis and subsequently attenuated synaptic loss. Our study provided a novel therapeutic mechanism for EPCs.