GRN mutation spectrum and genotype-phenotype correlation in Chinese dementia patients: data from PUMCH dementia cohort.

BACKGROUND: METHODS: The GRN mutations, especially of the loss of function type, are causative of frontotemporal dementia (FTD). However, several GRN variants can be found in other neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease. So far, there have been over 300 GRN mutations reported globally. However, the genetic spectrum and phenotypic characteristics have not been fully elucidated in Chinese population.The participants were from the dementia cohort of Peking Union Medical College Hospital (n=1945). They received history inquiry, cognitive evaluation, brain imaging and exome sequencing. The dementia subjects carrying the rare variants of the GRN were included in this study. Those with the pathogenic or likely pathogenic variants of other dementia-related genes were excluded. RESULTS: 14 subjects carried the rare variants of GRN. They were clinically diagnosed with behavioural variant of FTD (n=2), non-fluent/agrammatic variant primary progressive aphasia (PPA, n=3), semantic variant PPA (n=1), AD (n=6) and mixed dementia (n=2). 13 rare variants of GRN were found, including 6 novel variants (W49X, S226G, M152I, A91E, G79E and A303S). The most prevalent symptom was amnesia (85.7%, 12/14), followed by psychiatric and behavioural disorder (78.6%, 11/14). In terms of lobar atrophy, temporal atrophy/hypometabolism was the most common (85.7%, 12/14), followed by parietal atrophy/hypometabolism (78.6%, 11/14). CONCLUSION: The novel GRN variants identified in this study contribute to enrich the GRN mutation repertoire. There is phenotypic similarity and diversity among Chinese patients with the GRN mutations.

Cerebrospinal Fluid Alzheimer's Biomarkers and Neurofilament Light Profile of Idiopathic Normal Pressure Hydrocephalus in China: A PUMCH Cohort Study.

INTRODUCTION: Idiopathic normal pressure hydrocephalus (iNPH) is one of the potentially reversible dementias. Early and accurate diagnosis is important for patients' prognosis. Emerging evidence shows fluid biomarkers are useful in diagnosis and pathophysiological research of iNPH. METHODS: Probable iNPH and Alzheimer's disease (AD) patients were recruited. Clinical diagnosis was performed according to international guidelines. CSF collection complied with a standard protocol. Commercial accessible ELISA kits were introduced for measurement of CSF t-tau, p-tau181, Aß42, and NfL. RESULTS: Twenty-seven iNPH, 27 AD, and 18 controls were included. The profiles of CSF t-tau, p-tau181, and t-tau/Aß42 in the iNPH and AD were significantly different (p < 0.0001). The profiles of CSF t-tau, p-tau181, and t-tau/Aß42 in the iNPH and control were not different (p > 0.05). Level of CSF Aß42 in iNPH was significantly lower than control (p < 0.0001) and also significantly higher than AD (p < 0.05). NfL level in iNPH and AD was increased, but its level in iNPH was significantly lower than that in AD (p = 0.005). NfL and t-tau level in the iNPH group was significantly correlated (coefficient = 0.649, p = 0.005), but not in AD (coefficient = 0.298, p = 0.157). CONCLUSION: Alzheimer's CSF biomarker profile of iNPH subjects showed moderately decreased Aß42 and normal t-tau, p-tau181, and t-tau/Aß42, which was distinguishable from AD. The different profiles and correlation of t-tau and NfL suggested different pathophysiology of AD and iNPH. t-tau was relatively an AD-specific neurodegenerative biomarker compared to NfL.

Comparison of ß-Amyloid Plaque Labeling Methods: Antibody Staining, Gallyas Silver Staining, and Thioflavin-S Staining.

Objective To evaluate senile plaque formation and compare the sensitivity of three different ß-amyloid (Aß) labeling methods (antibody staining, Gallyas silver staining, and thioflavin-S staining) to detect Aß deposition.Methods APPswe/PSEN1dE9 transgenic mice (APP/PS1) of different ages were used to examine spatiotemporal changes in Aß plaque deposition. Antibody staining, Gallyas silver staining, and thioflavin-S staining were used to detect Aß plaque deposition in the same brain region of adjacent slices from model mice, and the results were compared.Results With aging, Aß plaques first appeared in the cortex and then the deposition increased throughout the whole brain. Significantly greater plaque deposition was detected by 6E10 antibody than that analyzed with Gallyas silver staining or thioflavin-S staining (P<0.05). Plaque deposition did not show significant difference between the APP/PS1 mice brains assayed with Gallyas silver staining and ones with thioflavin-S staining (P=0.0033).Conclusions The APP/PS1 mouse model of Alzheimer's disease could mimick the progress of Aß plaques occurred in patients with Alzheimer's disease. Antibody detection of Aß deposition may be more sensitive than chemical staining methods.

Expressions of CCAAT/enhancer-binding Protein Homologous Protein and Calnexin in the Hippocampus of a Mouse Model of Mesial Temporal Lobe Epilepsy.

Objective To explore the temporal and spatial distribution of CCAAT/enhancer-binding protein homologous protein (CHOP) and calnexin (CNX) in the dentate gyrus of mesial temporal lobe epilepsy (mTLE) mouse model. Methods We used kainic acid (KA) to induce acute phase (12 h and 24 h) mTLE mouse models and performed Western blotting and immunofluorescence to detect the different expressions and distribution pattern of CHOP and CNX in CA3 of the hippocampus. Results Compared with the controls,the expressions of CHOP(F=1.136,P=0.4069) and CNX (F=2.378,P=0.2087) did not increase in CA3 of hippocampus 12 h following KA injection in the acute phase of mTLE mouse models,whereas the expressions in CA1 and CA3 of hippocampus 24 h after injection were significantly higher (F=8.510,P=0.0362;F=6.968,P=0.0497,respectively). As shown by immunofluorescence analysis,CHOP was expressed mainly in CA3 of hippocampus 12 h after KA injection,and increased in CA1 and CA3 24 h after KA administration. Compared with the controls,the expressions of CHOP(F=24.480,P=0.0057) and CNX (F=7.149,P=0.0478) were significantly higher 24 h after KA injection.Conclusions The expression of CHOP increases along with the progression of seizures,indicating the increased level of endoplasmic reticulum stress. An increasing number of CNX,which serves as molecular chaperone,may be needed to facilitate the unfolded protein to complete the folding process.

Establishment of a chronic restraint stress model of depression with C57BL/6J mice.

OBJECTIVE: To establish a chronic restraint stress (CRS) model of depression,using C57BL/6J mice. METHODS: Totally 20 C57BL/6J mice were screened by weight,sucrose preference,and the results of open-field test. Then,they were equally randomized into two groups:normal control (NC) group and CRS group. Mice in the CRS group were under restraint 4 hours a day and their behavioral changes were evaluated after 21 days. RESULTS: The immobility time was significantly longer in CRS mice [(131.70 ± 21.65) s] compared with controls [(68.88 ± 8.43) s] (P=0.0304). CRS mice showed a significant decrease in sucrose preference during the time 0-24 h [(66.21 ±3.24)% vs.(79.46 ± 3.85)%, P=0.0196] and 0-48 h [(73.25 ± 1.50)% vs.(80.20 ± 2.26)%, P=0.0248] compared with controls. CONCLUSION: The C57BL/6J mice CRS models of depression were successfully established.

Neuromodulatory Compensation of Cortical Neural Activity on Electrodeposited Pt/Ir Modified Microelectrode Arrays for Temperature Transients.

Temperature has a profound influence on various neuromodulation processes and has emerged as a focal point. However, the effects of acute environmental temperature fluctuations on cultured cortical networks have been inadequately elucidated. To bridge this gap, we have developed a brain-on-a-chip platform integrating cortical networks and electrodeposited Pt/Ir modified microelectrode arrays (MEAs) with 3D-printed bear-shaped triple chambers, facilitating control of temperature transients. This innovative system administers thermal stimuli while concurrently monitoring neuronal activity, including spikes and local field potentials, from 60 microelectrodes (diameter: 30 µm; impedance: 9.34 ± 1.37 kΩ; and phase delay: -45.26 ± 2.85°). Temperature transitions of approximately ±10 °C/s were applied to cortical networks on MEAs via in situ perfusion within the triple chambers. Subsequently, we examined the spatiotemporal dynamics of the brain-on-a-chip under temperature regulation at both the group level (neuronal population) and their interactions (network dynamics) and the individual level (cellular activity). Specifically, we found that after the temperature reduction neurons enhanced the overall information transmission efficiency of the network through synchronous firing to compensate for the decreased efficiency of single-cell level information transmission, in contrast to temperature elevation. By leveraging the integration of high-performance MEAs with perfusion chambers, this investigation provides a comprehensive understanding of the impact of temperature on the spatiotemporal dynamics of neural networks, thereby facilitating future exploration of the intricate interplay between temperature and brain function.

SWCNTs/PEDOT:PSS nanocomposites-modified microelectrode arrays for revealing locking relations between burst and local field potential in cultured cortical networks.

Burst and local field potential (LFP) are fundamental components of brain activity, representing fast and slow rhythms, respectively. Understanding the intricate relationship between burst and LFP is crucial for deciphering the underlying mechanisms of brain dynamics. In this study, we fabricated high-performance microelectrode arrays (MEAs) using the SWCNTs/PEDOT:PSS nanocomposites, which exhibited favorable electrical properties (low impedance: 12.8 ± 2.44 kΩ) and minimal phase delay (-11.96 ± 1.64°). These MEAs enabled precise exploration of the burst-LFP interaction in cultured cortical networks. After a 14-day period of culture, we used the MEAs to monitor electrophysiological activities and revealed a time-locking relationship between burst and LFP, indicating the maturation of the neural network. To further investigate this relationship, we modulated burst firing patterns by treating the neural culture with increasing concentrations of glycine. The results indicated that glycine effectively altered burst firing patterns, with both duration and spike count increasing as the concentration rose. This was accompanied by an enhanced level of time-locking between burst and LFP but a decrease in synchrony among neurons. This study not only highlighted the pivotal role of SWCNTs/PEDOT:PSS-modified MEAs in elucidating the interaction between burst and LFP, bridging the gap between slow and fast brain rhythms in vitro but also provides valuable insights into the potential therapeutic strategies targeting neurological disorders associated with abnormal rhythm generation.

[Expression of growth-associated protein 43 in the hippocampus of mesial temporal lobe epilepsy mouse model].

OBJECTIVE: To explore the temporal and spatial distribution of growth-associated protein 43(GAP-43)and phosphorylated growth-associated protein 43(p-GAP-43)in the dentate gyrus of mesial temporal lobe epilepsy(MTLE)mouse model. METHODS: MTLE mouse model was established by using the kainic acid(KA)induction. Immunohistochemistry and Western blotting were applied to detect the expressions of GAP-43 and p-GAP-43 in different stages of epileptogenesis. RESULTS: Both in the epileptic and control mice, high GAP-43 expression level was detected in the dentate gyrus, hilus, and inner molecular layer of hippocampus. Decreased p-GAP-43 expression was detected 5 days, 2 weeks, and 5 weeks after KA-induced seizures. CONCLUSION: The decreased p-GAP-43 expression in the duration of seizure may play an important role in the synaptic reorganization of the sclerotic hippocampus.

Long-term outcomes of classic and novel anti-seizure medication in a kainate-induced model of chronic epilepsy.

OBJECTIVE: Intrahippocampal injection of kainate (KA) is a reliable model of temporal lobe epilepsy (TLE) that replicates spontaneous recurrent seizures. Both electrographic seizures and electroclinical seizure (most generalized seizure) can be detected in KA model. Electrographic seizures such as high-voltage sharp waves (HVSWs) and hippocampal paroxysmal discharges (HPDs) are far more common and attracting much attention. A comprehensive study on the anticonvulsant effects of classic and novel antiseizure medications (ASMs) on spontaneous electroclinical seizures, especially during long-term treatment, is still lacking. Here, we evaluated the effects of six ASMs in this model on electroclinical seizures over eight weeks. METHODS: Using 24-hour continuous electroencephalographical (EEG) monitoring in free-moving mice, we tested the effectiveness of six ASMs (valproic acid, VPA; carbamazepine, CBZ; lamotrigine, LTG; perampanel, PER; brivaracetam, BRV; and everolimus, EVL) on the electroclinical seizures over eight weeks in the intrahippocampal kainate mouse model. RESULTS: VPA, CBZ, LTG, PER and BRV significantly suppressed electroclinical seizures in the early stages of treatment, but the mice gradually developed resistance to these drugs. Overall, the mean frequency of electroclinical seizures was not significantly lower during the 8-week treatment than that at baseline in any ASM-treated group. The individual responses to ASMs varied widely. CONCLUSION: Long-term treatment with VPA, LTG, CBZ, PER, BRV and EVL did not relieve electroclinical seizures in this TLE model. Additionally, the window for screening new ASMs in this model should be set to at least 3 weeks to account for drug resistance.

LHPP-mediated inorganic pyrophosphate hydrolysis-driven lysosomal acidification in astrocytes regulates adult neurogenesis.

In bacteria, archaea, protists, and plants, the hydrolysis of pyrophosphate (PPi) by inorganic pyrophosphatase (PPase) can, under stress conditions, substitute for ATP-driven proton flux to generate a proton gradient and induce luminal acidification. However, this strategy is considered to be lost in eukaryotes. Here, we report that LHPP, a poorly understood PPase that exhibits activity at acidic pH, is primarily expressed in astrocytes and partly localized on lysosomal membranes. Under stress conditions, LHPP is recruited to vacuolar ATPase (V-ATPase) and facilitates V-ATPase-dependent proton transport and lysosomal acidification by hydrolyzing PPi. LHPP knockout (KO) mice have no discernable phenotype but are resilient to chronic-stress-induced depression-like behaviors. Mechanistically, LHPP deficiency prevents lysosome-dependent degradation of C/EBPß and induces the expression of a group of chemokines that promote adult neurogenesis. Together, these findings suggest that LHPP is likely to be a therapeutic target for stress-related brain disease.

PPy/SWCNTs-Modified Microelectrode Array for Learning and Memory Model Construction through Electrical Stimulation and Detection of In Vitro Hippocampal Neuronal Network.

The learning and memory functions of the brain remain unclear, which are in urgent need for the detection of both a single cell signal with high spatiotemporal resolution and network activities with high throughput. Here, an in vitro microelectrode array (MEA) was fabricated and further modified with polypyrrole/carboxylated single-walled carbon nanotubes (PPy/SWCNTs) nanocomposites as the interface between biological and electronic systems. The deposition of the nanocomposites significantly improved the performance of microelectrodes including low impedance (60.3 ± 28.8 k Ω), small phase delay (-32.8 ± 4.4°), and good biocompatibility. Then the modified MEA was used to apply learning training and test on hippocampal neuronal network cultured for 21 days through electrical stimulation, and multichannel electrophysiological signals were recorded simultaneously. During the process of learning training, the stimulus/response ratio of the hippocampal learning population gradually increased and the response time gradually decreased. After training, the mean spikes in burst, number of bursts, and mean burst duration increased by 53%, 191%, and 52%, respectively, and the correlation of neurons in the network was significantly enhanced from 0.45 ± 0.002 to 0.78 ± 0.002. In addition, the neuronal network basically retained these characteristics for at least 5 h. These results indicated that we have successfully constructed a learning and memory model of hippocampal neurons on the in vitro MEA, contributing to understanding learning and memory based on synaptic plasticity. The proposed PPy/SWCNTs-modified in vitro MEA will provide a promising platform for the exploration of learning and memory mechanism and their applications in vitro.

Spatio-temporal expression study of phosphorylated 70-kDa ribosomal S6 kinase (p70S6k) in mesial temporal lobe epilepsy.

OBJECTIVE: To determine the spatio-temporal expression of p70S6k activation in hippocampus in mesial temporal lobe epilepsy. METHODS: Temporal lobe epilepsy model was established by stereotaxically unilateral and intrahippocampal injection of kainite acid (KA) in adult male C57BL/6 mice. Latent and chronic epileptogenesis were represented by mice 5 days after KA injection (n = 5) and mice 5 weeks after KA injection (n = 8), respectively. Control mice (n = 5) were injected with saline. Immunohistochemical assays were performed on brain sections of the mice. RESULTS: Hippocampus both ipsilateral and contralateral to the KA injection displayed significantly up-regulated pS6 immunoreactivity in dispersed granule cells in 5-day and 5-week model mice. CONCLUSION: The activation of p70S6k is mainly located in the dentate gyrus in KA-induced mouse model of temporal lobe epilepsy, indicating that the activation may be related with the disperse degree and hypertrophy of granule cells.

Pharmacological induction of AMFR increases functional EAAT2 oligomer levels and reduces epileptic seizures in mice.

Dysregulation of excitatory amino acid transporter 2 (EAAT2) contributes to the development of temporal lobe epilepsy (TLE). Several strategies for increasing total EAAT2 levels have been proposed. However, the mechanism underlying the oligomeric assembly of EAAT2, impairment of which inhibits the formation of functional oligomers by EAAT2 monomers, is still poorly understood. In the present study, we identified E3 ubiquitin ligase AMFR as an EAAT2-interacting protein. AMFR specifically increased the level of EAAT2 oligomers rather than inducing protein degradation through K542-specific ubiquitination. By using tissues from humans with TLE and epilepsy model mice, we observed that AMFR and EAAT2 oligomer levels were simultaneously decreased in the hippocampus. Screening of 2386 FDA-approved drugs revealed that the most common analgesic/antipyretic medicine, acetaminophen (APAP), can induce AMFR transcriptional activation via transcription factor SP1. Administration of APAP protected against pentylenetetrazol-induced epileptogenesis. In mice with chronic epilepsy, APAP treatment partially reduced the occurrence of spontaneous seizures and greatly enhanced the antiepileptic effects of 17AAG, an Hsp90 inhibitor that upregulates total EAAT2 levels, when the 2 compounds were administered together. In summary, our studies reveal an essential role for AMFR in regulating the oligomeric state of EAAT2 and suggest that APAP can improve the efficacy of EAAT2-targeted antiepileptic treatments.

Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-ß and consequent Alzheimer's disease risk.

Amyloid-ß (Aß) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer's disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.-2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1's role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aß generation through inhibiting ß-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.

CSF biomarkers for early-onset Alzheimer's disease in Chinese population from PUMCH dementia cohort.

Introduction: Alzheimer's disease (AD) is one of the highly concerned degenerative disorders in recent decades. Though vast amount of researches has been done in various aspects, early-onset subtype, however, needs more investigation in diagnosis for its atypical manifestations and progression process. Fundamental CSF biomarkers of early-onset AD are explored in PUMCH dementia cohort to depict its laboratory characteristics. Materials and methods: A total of 125 individuals (age of onset <65 years old) from PUMCH dementia cohort were recruited consecutively and classified into AD, non-AD dementia, and control groups. Levels of amyloid-ß 42 (Aß42), total tau (t-tau) and phosphorylated tau (p-tau) were measured using ELISA INNOTEST (Fujirebio, Ghent, Belgium). Students' t-test or non-parametric test are used to evaluate the differences between groups. Area under curve (AUC) of receiver operating characteristic (ROC) curve was introduced to prove the diagnostic powers of corresponding markers. Logistic regression is used to establish diagnostic model to combine several markers together to promote the diagnostic power. Results: The average of all three biomarkers and two calculated ratios (t-tau/Aß42, p-tau/Aß42) were statistically different in the AD group compared with the other two groups (Ps < 0.01). From our data, we were able to provide cutoff values (Aß42 < 570.9 pg/mL; p-tau > 56.49 pg/mL; t-tau > 241.6 pg/mL; t-tau/Aß42 > 0.529; p-tau/Aß42 > 0.0846) with acceptable diagnostic accuracy compared to other studies. Using a combination of biomarkers and logistic regression (area under curve 0.951), we were able to further improve diagnostic efficacy. Discussion: Our study supports the diagnostic usefulness of biomarkers and defined cutoff values to diagnose early-onset AD. We showed that the ratios of t-tau/Aß42 and p-tau/Aß42 are more sensitive than relying on Aß42 levels alone, and that we can further improve diagnostic accuracy by combining biomarkers.

PSEN2 Mutation Spectrum and Novel Functionally Validated Mutations in Alzheimer's Disease: Data from PUMCH Dementia Cohort.

BACKGROUND: The established causative mutations in the APP, PSEN1, and PSEN2 can explain less than 1%,Alzheimer's disease (AD) patients. Of the identified variants, the PSEN2 mutations are even less common. OBJECTIVE: With the genetic study from the dementia cohort of Peking Union Medical College Hospital (PUMCH), we aim to illustrate the PSEN2 mutation spectrum and novel functionally validated mutations in Chinese AD patients. METHODS: 702 AD participants, aged 30-85, were identified in PUMCH dementia cohort. They all received history inquiry, physical examination, biochemical test, cognitive evaluation, brain CT/MRI, and next-generation DNA sequencing. Functional analysis was achieved by transfection of the HEK293 cells with plasmids harboring the wild-type PSEN2 or candidate mutations. RESULTS: Nine PSEN2 rare variants were found, including two reported (M239T, R62C) and seven novel variants (N141S, I368F, L396I, G117X, I146T, S147N, H220Y). The HEK293 cells transfected with the PSEN2 N141S, M239T, I368F plasmids showed higher Aß42 and Aß42/Aß40 levels relative to the wild-type PSEN2. The PSEN2 L396I, G117X, S147N, H220Y, and R62C did not alter Aß42, Aß40 levels, or Aß42/Aß40 ratio. 1.9%,(13/702) subjects harbored rare PSEN2 variants. 0.4%,(3/702) subjects carried pathogenic/likely pathogenic PSEN2 mutations. The three subjects with the functionally validated PSEN2 mutations were all familial early-onset AD patients. The common symptoms included amnesia and mental symptom. Additionally, the M239T mutation carrier presented with dressing apraxia, visuospatial agraphia, dyscalculia and visual mislocalization. CONCLUSION: The PSEN2 N141S, M239T, and I368F are functionally validated mutations.

A Neural Sensor with a Nanocomposite Interface for the Study of Spike Characteristics of Hippocampal Neurons under Learning Training.

Both the cellular- and population-level properties of involved neurons are essential for unveiling the learning and memory functions of the brain. To give equal attention to these two aspects, neural sensors based on microelectrode arrays (MEAs) have been in the limelight due to their noninvasive detection and regulation capabilities. Here, we fabricated a neural sensor using carboxylated graphene/3,4-ethylenedioxythiophene:polystyrenesulfonate (cGO/PEDOT:PSS), which is effective in sensing and monitoring neuronal electrophysiological activity in vitro for a long time. The cGO/PEDOT:PSS-modified microelectrodes exhibited a lower electrochemical impedance (7.26 ± 0.29 kΩ), higher charge storage capacity (7.53 ± 0.34 mC/cm2), and improved charge injection (3.11 ± 0.25 mC/cm2). In addition, their performance was maintained after 2 to 4 weeks of long-term cell culture and 50,000 stimulation pulses. During neural network training, the sensors were able to induce learning function in hippocampal neurons through precise electrical stimulation and simultaneously detect changes in neural activity at multiple levels. At the cellular level, not only were three kinds of transient responses to electrical stimulation sensed, but electrical stimulation was also found to affect inhibitory neurons more than excitatory neurons. As for the population level, changes in connectivity and firing synchrony were identified. The cGO/PEDOT:PSS-based neural sensor offers an excellent tool in brain function development and neurological disease treatment.

High-Throughput PEDOT:PSS/PtNPs-Modified Microelectrode Array for Simultaneous Recording and Stimulation of Hippocampal Neuronal Networks in Gradual Learning Process.

When it comes to mechanisms of brain functions such as learning and memory mediated by neural networks, existing multichannel electrophysiological detection and regulation technology at the cellular level does not suffice. To address this challenge, a 128-channel microelectrode array (MEA) was fabricated for electrical stimulation (ES) training and electrophysiological recording of the hippocampal neurons in vitro. The PEDOT:PSS/PtNPs-coated microelectrodes dramatically promote the recording and electrical stimulation performance. The MEA exhibited low impedance (10.94 ± 0.49 kohm), small phase delay (-12.54 ± 0.51°), high charge storage capacity (14.84 ± 2.72 mC/cm2), and high maximum safe injection charge density (4.37 ± 0.22 mC/cm2), meeting the specific requirements for training neural networks in vitro. A series of ESs at various frequencies was applied to the neuronal cultures in vitro, seeking the optimum training mode that enables the neuron to display the most obvious plasticity, and 1 Hz ES was determined. The network learning process, including three consecutive trainings, affected the original random spontaneous activity. Along with that, the firing pattern gradually changed to burst and the correlation and synchrony of the neuronal activity in the network have progressively improved, increasing by 314% and 240%, respectively. The neurons remembered these changes for at least 4 h. Collectively, ES activates the learning and memory functions of neurons, which is manifested in transformations in the discharge pattern and the improvement of network correlation and synchrony. This study offers a high-performance MEA revealing the underlying learning and memory functions of the brain and therefore serves as a useful tool for the development of brain functions in the future.

Association Between Common Variants of APOE, ABCA7, A2M, BACE1, and Cerebrospinal Fluid Biomarkers in Alzheimer's Disease: Data from the PUMCH Dementia Cohort.

BACKGROUND: The previous studies have identified several genes in relation to Alzheimer's disease (AD), such as ABCA7, CR1, etc. A few studies have explored the association between the common variants, mainly in the non-coding regions of these genes, and cerebrospinal fluid (CSF) biomarkers. Fewer studies target the variants in the coding regions. OBJECTIVE: To illustrate the association between the common variants within or adjacent to the coding regions of AD susceptible genes and CSF biomarkers in AD patients. METHODS: 75 sporadic probable AD patients were extracted from the dementia cohort of Peking Union Medical College Hospital. They all had history inquiry, physical examination, blood test, cognitive assessment, brain MRI, CSF testing of Aß42, 181p-tau, and t-tau, and next-generation DNA sequencing. Sixty-nine common single nucleotide polymorphisms (SNPs) (minor allele frequency > 0.01) within or near the coding region of 13 AD susceptible genes were included in the analysis. RESULTS: The rs7412-CC (APOE) genotype showed lower CSF Aß42 level and higher p-tau/Aß42 ratio than the rs7412-CT genotype. The rs3752246-C (ABCA7) allele correlated with lower CSF Aß42 level. The alternate alleles of six ABCA7 SNPs were related to lower CSF p-tau, including rs3745842, rs3764648, rs3764652, rs4147930, rs4147934 and rs881768. The rs11609582-TT (A2M) genotype showed higher CSF p-tau than the rs11609582-TA genotype. The p-tau/Aß42 ratio was higher in the rs490460-TT (BACE1) genotype relative to the rs490460-GT genotype. CONCLUSION: Some common variants within or near the coding regions of APOE, ABCA7, A2M, and BACE1 are associated with CSF Aß42, p-tau. or p-tau/Aß42.

[Role of beta-catenin in the pathogenesis of mesial temporal lobe epilepsy].

OBJECTIVE: To explore the role of beta-catenin in the pathogenesis of mesial temporal lobe epilepsy. METHODS: Kainic acid-induced rat models of medial temporal lobe epilepsy was established. The expression of beta-catenin in the normal mice and the model mice were detected using Western blot analysis. The expression of beta-catenin at human hippocampus was detected using immunohistochemical analysis and immunofluorescence and compared between patients with non-hippocampal sclerosis temporal lobe epilepsy and those with hippocampal sclerosis epilepsy. RESULTS: The pathologies of model mice were similar with those in mice with hippocampal sclerosis temporal lobe epilepsy, demonstrating that the mice model was successfully established. Western blot analysis showed no significant difference of beta-catenin expression between normal mice and model mice. As shown by immunohistochemical analysis and immunofluorescence, beta-catenin expression in human hippocampus was also not significantly different between patients with temporal lobe epilepsy without hippocampal sclerosis and those with hippocampal sclerosis. CONCLUSION: Beta-catenin may not be involved in the development of hippocampal sclerosis of mesial temporal lobe epilepsy.