Adult hippocampal neurogenesis and its role in Alzheimer's disease

MET receptor tyrosine kinase promotes the generation of functional synapses in adult cortical circuits

JOURNAL/nrgr/04.03/01300535-202505000-00026/figure1/v/2024-07-28T173839Z/r/image-tiff Loss of synapse and functional connectivity in brain circuits is associated with aging and neurodegeneration, however, few molecular mechanisms are known to intrinsically promote synaptogenesis or enhance synapse function. We have previously shown that MET receptor tyrosine kinase in the developing cortical circuits promotes dendritic growth and dendritic spine morphogenesis. To investigate whether enhancing MET in adult cortex has synapse regenerating potential, we created a knockin mouse line, in which the human MET gene expression and signaling can be turned on in adult (10-12 months) cortical neurons through doxycycline-containing chow. We found that similar to the developing brain, turning on MET signaling in the adult cortex activates small GTPases and increases spine density in prefrontal projection neurons. These findings are further corroborated by increased synaptic activity and transient generation of immature silent synapses. Prolonged MET signaling resulted in an increased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/N-methyl-D-aspartate (AMPA/NMDA) receptor current ratio, indicative of enhanced synaptic function and connectivity. Our data reveal that enhancing MET signaling could be an interventional approach to promote synaptogenesis and preserve functional connectivity in the adult brain. These findings may have implications for regenerative therapy in aging and neurodegeneration conditions.

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development. Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function. Increasing amounts of evidence highlight several key points: (1) Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer's disease and Parkinson's disease, and potentially, similar alterations occur in humans. (2) Genetic mutations of Netrin-1 receptors increase an individuals' susceptibility to neurodegenerative disorders. (3) Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function. (4) Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers. These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases. Through a comprehensive review of Netrin-1 signaling pathways, our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

Establishment of human cerebral organoid systems to model early neural development and assess the central neurotoxicity of environmental toxins

JOURNAL/nrgr/04.03/01300535-202501000-00032/figure1/v/2024-05-14T021156Z/r/image-tiff Human brain development is a complex process, and animal models often have significant limitations. To address this, researchers have developed pluripotent stem cell-derived three-dimensional structures, known as brain-like organoids, to more accurately model early human brain development and disease. To enable more consistent and intuitive reproduction of early brain development, in this study, we incorporated forebrain organoid culture technology into the traditional unguided method of brain organoid culture. This involved embedding organoids in matrigel for only 7 days during the rapid expansion phase of the neural epithelium and then removing them from the matrigel for further cultivation, resulting in a new type of human brain organoid system. This cerebral organoid system replicated the temporospatial characteristics of early human brain development, including neuroepithelium derivation, neural progenitor cell production and maintenance, neuron differentiation and migration, and cortical layer patterning and formation, providing more consistent and reproducible organoids for developmental modeling and toxicology testing. As a proof of concept, we applied the heavy metal cadmium to this newly improved organoid system to test whether it could be used to evaluate the neurotoxicity of environmental toxins. Brain organoids exposed to cadmium for 7 or 14 days manifested severe damage and abnormalities in their neurodevelopmental patterns, including bursts of cortical cell death and premature differentiation. Cadmium exposure caused progressive depletion of neural progenitor cells and loss of organoid integrity, accompanied by compensatory cell proliferation at ectopic locations. The convenience, flexibility, and controllability of this newly developed organoid platform make it a powerful and affordable alternative to animal models for use in neurodevelopmental, neurological, and neurotoxicological studies.

Gene interactions analysis of brain spatial transcriptome for Alzheimer's disease

Recent studies have explored the spatial transcriptomics patterns of Alzheimer's disease (AD) brain by spatial sequencing in mouse models, enabling the identification of unique genome-wide transcriptomic features associated with different spatial regions and pathological status. However, the dynamics of gene interactions that occur during amyloid-β accumulation remain largely unknown. In this study, we performed analyses on ligand-receptor communication, transcription factor regulatory network, and spot-specific network to reveal the dependence and the dynamics of gene associations/interactions on spatial regions and pathological status with mouse and human brains. We first used a spatial transcriptomics dataset of the App NL-G-F knock-in AD and wild-type mouse model. We revealed 17 ligand-receptor pairs with opposite tendencies throughout the amyloid-β accumulation process and showed the specific ligand-receptor interactions across the hippocampus layers at different extents of pathological changes. We then identified nerve function related transcription factors in the hippocampus and entorhinal cortex, as well as genes with different transcriptomic association degrees in AD versus wild-type mice. Finally, another independent spatial transcriptomics dataset from different AD mouse models and human single-nuclei RNA-seq data/AlzData database were used for validation. This is the first study to identify various gene associations throughout amyloid-β accumulation based on spatial transcriptomics, establishing the foundations to reveal advanced and in-depth AD etiology from a novel perspective based on the comprehensive analyses of gene interactions that are spatio-temporal dependent.

Transcript errors generate amyloid-like proteins in huwman cells

Aging is characterized by the accumulation of proteins that display amyloid-like behavior. However, the molecular mechanisms by which these proteins arise remain unclear. Here, we demonstrate that amyloid-like proteins are produced in a variety of human cell types, including stem cells, brain organoids and fully differentiated neurons by mistakes that occur in messenger RNA molecules. Some of these mistakes generate mutant proteins already known to cause disease, while others generate proteins that have not been observed before. Moreover, we show that these mistakes increase when cells are exposed to DNA damage, a major hallmark of human aging. When taken together, these experiments suggest a mechanistic link between the normal aging process and age-related diseases.

Structural inequality and temporal brain dynamics across diverse samples

BACKGROUND

Structural income inequality - the uneven income distribution across regions or countries - could affect brain structure and function, beyond individual differences. However, the impact of structural income inequality on the brain dynamics and the roles of demographics and cognition in these associations remains unexplored.

METHODS

Here, we assessed the impact of structural income inequality, as measured by the Gini coefficient on multiple EEG metrics, while considering the subject-level effects of demographic (age, sex, education) and cognitive factors. Resting-state EEG signals were collected from a diverse sample (countries = 10; healthy individuals = 1394 from Argentina, Brazil, Colombia, Chile, Cuba, Greece, Ireland, Italy, Turkey and United Kingdom). Complexity (fractal dimension, permutation entropy, Wiener entropy, spectral structure variability), power spectral and aperiodic components (1/f slope, knee, offset), as well as graph-theoretic measures were analysed.

FINDINGS

Despite variability in samples, data collection methods, and EEG acquisition parameters, structural inequality systematically predicted electrophysiological brain dynamics, proving to be a more crucial determinant of brain dynamics than individual-level factors. Complexity and aperiodic activity metrics captured better the effects of structural inequality on brain function. Following inequality, age and cognition emerged as the most influential predictors. The overall results provided convergent multimodal metrics of biologic embedding of structural income inequality characterised by less complex signals, increased random asynchronous neural activity, and reduced alpha and beta power, particularly over temporoposterior regions.

CONCLUSION

These findings might challenge conventional neuroscience approaches that tend to overemphasise the influence of individual-level factors, while neglecting structural factors. Results pave the way for neuroscience-informed public policies aimed at tackling structural inequalities in diverse populations.

Integrating adult neurogenesis and human brain organoid models to advance epilepsy and associated behavioral research

Epilepsy is a chronic neurological disorder characterized by recurring, unprovoked seizures, asymmetrical electroencephalogram patterns, and other pathological abnormalities. The hippocampus plays a pivotal role in learning, memory consolidation, attentional control, and pattern separation. Impairment of hippocampal network circuitry can induce long-term cognitive and memory dysfunction. In this review, we discuss how aberrant adult neurogenesis and plasticity collectively alter the network balance for information processing within the hippocampal neural network. Subsequently, we explore the potential of human brain organoids integrated into microelectrode array technology as an electrophysiological tool. We also discuss the utilization of a closed-loop platform that connects the brain organoid to a mobile robot in a virtual environment. While in vivo models provide valuable insights into some aspects of epileptogenesis, such as the impact of adult neurogenesis on hippocampal function, brain organoids are indispensable for comprehensively studying epileptogenesis involving genetic mutations that underlie human epilepsy. More importantly, a combinational approach using brain organoids on MEA paves the way for studying impaired plasticity and abnormal information processing within epileptic neural networks. This innovative in vitro approach may provide a new pathway for investigating the behavioral outcomes of aberrant neural networks when integrated with a mobile robot, closing the loop between the neural network in brain organoids and the mobile robot. In this review, we aim to discuss the use of each model to study the behavioral changes in epilepsy and highlight the benefits of both in vivo and in vitro models for understanding the behavioral aspects of epilepsy.

Enhanced hippocampal TIAM2S expression alleviates cognitive deficits in Alzheimer's disease model mice

BACKGROUND

Dendritic spine dysfunction is a key feature of Alzheimer's disease (AD) pathogenesis. Human T-cell lymphoma invasion and metastasis 2 (TIAM2) is expressed in two isoforms, the full length (TIAM2L) and a short transcript (TIAM2S). Compared to TIAM2L protein, which is undetectable, TIAM2S protein is abundant in human brain tissue, especially the hippocampus, and can promote neurite outgrowth in our previous findings. However, whether enhanced hippocampal TIAM2S expression can alleviate cognitive deficits in Alzheimer's disease model mice remains unclear.

METHODS

We crossbred 3xTg-AD with TIAM2S mice to generate an AD mouse model that carries the human TIAM2S gene (3xTg-AD/TIAM2S mice). The Morris water maze and object location tests assessed hippocampus-dependent spatial memory. Lentiviral-driven shRNA or cDNA approaches were used to manipulate hippocampal TIAM2S expression. Golgi staining and Sholl analysis were utilized to measure neuronal dendrites and dendritic spines in the mouse hippocampi.

RESULTS

Compared to 3xTg-AD mice, 3xTg-AD/TIAM2S mice displayed improved cognitive functions. According to the hippocampus is one of the earliest affected brain regions by AD, we further injected TIAM2S shRNA or TIAM2S cDNA into mouse hippocampi to confirm whether manipulating hippocampal TIAM2S expression could affect AD-related cognitive functions. The results showed that the reduced hippocampal TIAM2S expression in 3xTg-AD/TIAM2S mice abolished the memory improvement effect, whereas increased hippocampal TIAM2S levels alleviated cognitive deficits in 3xTg-AD mice. Furthermore, we found that TIAM2S-mediated memory improvement was achieved by regulating dendritic plasticity.

CONCLUSIONS

These results will provide new insights into connecting TIAM2S with AD and support the notion that TIAM2S should be investigated as potential AD therapeutic targets.

Abnormal resting-state functional connectivity of hippocampal subregions in type 2 diabetes mellitus-associated cognitive decline

Objective

Type 2 diabetes mellitus (T2DM) over time predisposes to inflammatory responses and abnormalities in functional brain networks that damage learning, memory, or executive function. The hippocampus is a key region often reporting connectivity abnormalities in memory disorders. Here, we investigated peripheral inflammatory responses and resting-state functional connectivity (RSFC) changes characterized of hippocampal subregions in type 2 diabetes-associated cognitive decline (T2DACD).

Methods

The study included 16 patients with T2DM, 16 patients with T2DACD and 25 healthy controls (HCs). Subjects were assessed for cognitive performance, tested for the expression of inflammatory factors IL-6, IL-10 and TNF-α in peripheral serum, underwent resting-state functional magnetic resonance imaging scans, and analyzed for RSFC using the hippocampal subregions as seeds. We also calculated the correlation between cognitive performance and RSFC of hippocampal subregion, and analyzed the significantly altered RSFC values of T2DACD for Receiver Operating Characteristic (ROC) analysis.

Results

T2DACD patients showed a decline in their ability to complete cognitive assessment scales and experimental paradigms, and T2DM did not show abnormal cognitive performance. IL-6 expression was increased in peripheral serum in both T2DACD and T2DM. Compared with HCs, T2DACD showed abnormalities RSFC of the left anterior hippocampus with left precentral gyrus and left angular gyrus. T2DM showed abnormalities RSFC of the left middle hippocampus with right medial frontal gyrus, right anterior and middle hippocampus with left precuneus, left anterior hippocampus with right precuneus and right posterior middle temporal gyrus. Compared with T2DM, T2DACD showed abnormalities RSFC of the left posterior hippocampus and right middle hippocampus with left precuneus. In addition, RSFC in the left posterior hippocampus with left precuneus of T2DACD was positively correlated with Flanker conflict response time (r=0.766, P=0.001). In the ROC analysis, the significantly altered RSFC values of T2DACD achieved significant performance.

Conclusions

T2DACD showed a significant decrease in attentional inhibition and working memory, peripheral pro-inflammatory response increased, and abnormalities RSFC of the hippocampal subregions with default mode network and sensory-motor network. T2DM did not show a significant cognitive decline, but peripheral pro-inflammatory response increased and abnormalities RSFC of the hippocampus subregions occurred in the brain. In addition, the left precuneus may be a key brain region in the conversion of T2DM to T2DACD. The results of this study may provide a basis for the preliminary diagnosis of T2DACD.

Comparative outcomes of systemic diseases in people with type 2 diabetes, or obesity alone treated with and without GLP-1 receptor agonists: a retrospective cohort study from the Global Collaborative Network : Author list

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly used to manage type 2 diabetes (T2D) and obesity. Despite their recognized benefits in glycemic control and weight management, their impact on broader systemic has been less explored.

OBJECTIVE

This study aimed to evaluate the impact of GLP-1RAs on a variety of systemic diseases in people with T2D or obesity.

METHODS

We conducted a retrospective cohort study using data from the Global Collaborative Network, accessed through the TriNetX analytics platform. The study comprised two primary groups: individuals with T2D and those with obesity. Each group was further divided into subgroups based on whether they received GLP-1RA treatment or not. Data were analyzed over more than a 5-year follow-up period, comparing incidences of systemic diseases; systemic lupus erythematosus (SLE), systemic sclerosis (SS), rheumatoid arthritis (RA), ulcerative colitis (UC), crohn's disease (CD), alzheimer's disease (AD), parkinson's disease (PD), dementia, bronchial asthma (BA), osteoporosis, and several cancers.

RESULTS

In the T2D cohorts, GLP-1RA treatment was associated with significantly lower incidences of several systemic and metabolic conditions as compared to those without GLP-1RA, specifically, dementia (Risk Difference (RD): -0.010, p < 0.001), AD (RD: -0.003, p < 0.001), PD (RD: -0.002, p < 0.001), and pancreatic cancer (RD: -0.003, p < 0.001). SLE and SS also saw statistically significant reductions, though the differences were minor in magnitude (RD: -0.001 and - 0.000 respectively, p < 0.001 for both). Conversely, BA a showed a slight increase in risk (RD: 0.002, p < 0.001).

CONCLUSIONS

GLP-1RAs demonstrate potential benefits in reducing the risk of several systemic conditions in people with T2D or obesity. Further prospective studies are needed to confirm these effects fully and understand the mechanisms.

The intricate interplay between microglia and adult neurogenesis in Alzheimer's disease

Microglia, the resident immune cells of the central nervous system, play a crucial role in regulating adult neurogenesis and contribute significantly to the pathogenesis of Alzheimer's disease (AD). Under physiological conditions, microglia support and modulate neurogenesis through the secretion of neurotrophic factors, phagocytosis of apoptotic cells, and synaptic pruning, thereby promoting the proliferation, differentiation, and survival of neural progenitor cells (NPCs). However, in AD, microglial function becomes dysregulated, leading to chronic neuroinflammation and impaired neurogenesis. This review explores the intricate interplay between microglia and adult neurogenesis in health and AD, synthesizing recent findings to provide a comprehensive overview of the current understanding of microglia-mediated regulation of adult neurogenesis. Furthermore, it highlights the potential of microglia-targeted therapies to modulate neurogenesis and offers insights into potential avenues for developing novel therapeutic interventions.

TESC overexpression mitigates amyloid-β-induced hippocampal atrophy and memory decline

BACKGROUND AND OBJECTIVES

Genome-wide association studies (GWASs) have identified numerous candidate genes for human brain-imaging phenotypes; however, the biological relevance of many of these genes remains unconfirmed. This study aimed to investigate the causal relationships among tescalcin (TESC) (a GWAS-indicated gene), hippocampal volume, Alzheimer's disease (AD), and the underlying biological mechanisms.

METHODS

Human transcriptional data were analyzed to confirm relative TESC expression in the hippocampus. In cell experiments, RNA-seq analysis was used to identify the potential biological pathways for TESC overexpression, and immunofluorescence imaging and cell viability assays were used to evaluate the effect of TESC overexpression on neuronal structure and survival. In animal experiments, the effects of TESC overexpression on hippocampal volume and cognitive function in normal mice and amyloid-β (Aβ)-induced AD mice were investigated by 9.4 T magnetic resonance imaging and behavioral tests. Underlying mechanisms were further assessed via western blotting and electrophysiological recordings.

RESULTS

Human transcriptional data demonstrated that TESC is primarily expressed in the hippocampus and neurons. TESC overexpression enhanced the viability of HT22 cells and reduced Aβ-induced cell death. In mouse models, Tesc-overexpressing mice revealed increased hippocampal volume, likely owing to enhanced cell viability and long-term potentiation (LTP), and reducing apoptotic- and oxidation-induced hippocampal damage. TESC overexpression could significantly mitigate Aβ-induced hippocampal atrophy and memory impairment, potentially by reducing Aβ-induced neuronal apoptosis and LTP weakening.

CONCLUSION

This study exemplifies the translation of GWAS findings into actionable biological knowledge and suggests that upregulation of TESC may offer a promising therapeutic strategy for AD.

Interplay of MeCP2/REST/Synaptophysin-BDNF and intranasal oxytocin influence on Aβ-induced memory and cognitive impairments

BACKGROUND

Alzheimer's disease (AD) is linked to the accumulation of Aβ, increased tau hyperphosphorylation, persistent neuroinflammation, and a decline in neurotrophic factors, neurogenesis, and synaptic plasticity. Oxytocin (OT) has a significant impact on memory and learning. We examined the influence of intranasal (IN) OT on synaptic plasticity, neurogenesis, histone acetylation, and spatial and cognitive memories in rats.

METHODS

Aβ25-35 (5 µg/2.5 µl) was administered bilaterally in the CA1 of male Wistar rats for four consecutive days. After seven days of recovery, OT (2 µg/µl, 10 µl in each nostril) was administered IN for seven consecutive days. Working, spatial, and cognitive memories, and gene expression of neurogenesis- and synaptic plasticity-involved factors were measured in the hippocampus. Histone acetylation (H3K9 and H4K8) was also measured using western blotting.

RESULTS

IN administration of OT significantly improved working and spatial memory impairment induced by Aβ and increased the factors involved in synaptic plasticity (MeCP2, REST, synaptophysin, and BDNF) and neurogenesis (Ki67 and DCX). We also found an enhancement in the levels of H3K9ac and H4K8ac following OT administration.

CONCLUSION

These findings indicated that IN OT could improve hippocampus-related behaviors by increasing synaptic plasticity, stimulating neurogenesis, and chromatin plasticity.

New BDNF and NT-3 Cyclic Mimetics Concur with Copper to Activate Trophic Signaling Pathways as Potential Molecular Entities to Protect Old Brains from Neurodegeneration

A low level of Neurotrophins (NTs), their Tyrosine Kinase Receptors (Trks), Vascular Endothelial Growth Factors (VEGFs) and their receptors, mainly VEGFR1 and VEGFR2, characterizes AD brains. The use of NTs and VEGFs as drugs presents different issues due to their low permeability of the blood-brain barrier, the poor pharmacokinetic profile, and the relevant side effects. To overcome these issues, different functional and structural NT mimics have been employed. Being aware that the N-terminus domain as the key domain of NTs for the binding selectivity and activation of Trks and the need to avoid or delay proteolysis, we herein report on the mimicking ability of two cyclic peptide encompassing the N-terminus of Brain Derived Growth Factor (BDNF), (c-[HSDPARRGELSV-]), cBDNF(1-12) and of Neurotrophin3 (NT3), (c-[YAEHKSHRGEYSV-]), cNT3(1-13). The two cyclic peptide features were characterized by a combined thermodynamic and spectroscopic approach (potentiometry, NMR, UV-vis and CD) that was extended to their copper(II) ion complexes. SH-SY5Y cell assays show that the Cu2+ present at the sub-micromolar level in the complete culture media affects the treatments with the two peptides. cBDNF(1-12) and cNT3(1-13) act as ionophores, induce neuronal differentiation and promote Trks and CREB phosphorylation in a copper dependent manner. Consistently, both peptide and Cu2+ stimulate BDNF and VEGF expression as well as VEGF release; cBDNF(1-12) and cNT3(1-13) induce the expression of Trks and VEGFRs.

Electroacupuncture activates AMPKα1 to improve learning and memory in the APP/PS1 mouse model of early Alzheimer's disease by regulating hippocampal mitochondrial dynamics

OBJECTIVE

Studies have shown that electroacupuncture (EA) can alleviate cognitive impairments from Alzheimer's disease (AD) by regulating the expression of adenosine monophosphate-activated protein kinase (AMPK), but the specific mechanism involved remains to be elucidated. Therefore, this study explores the potential mechanism by which EA improves cognitive function from the perspective of mitochondrial dynamics.

METHODS

The four-month-old transgenic mice with amyloid precursor protein (APP)/presenilin 1 (PS1) and AMPKα1-subunit conditional knockout (AMPKα1-cKO) were used for experiments. To evaluate the effects of EA treatment on cognitive function, the T-maze and Morris water maze were used. In addition, chemical exchange saturation transfer, thioflavin staining, transmission electron microscopy, mitochondrial membrane potential, and Western blotting were used to examine the potential mechanisms underlying the effects of EA on APP/PS1 mice.

RESULTS

Both APP/PS1 mice and AMPKα1-cKO mice exhibited dysfunction in mitochondrial dynamics accompanied by learning and memory impairment. Inactivation of the AMPK/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) pathway increased pathological amyloid-β (Aβ) deposition and aggravated the dysfunction in mitochondrial dynamics. In addition, EA rescued learning and memory deficits in APP/PS1 mice by activating the AMPK/PGC-1α pathway, specifically by reducing pathological Aβ deposition, normalizing energy metabolism, protecting the structure and function of mitochondria, increasing the levels of mitochondrial fusion proteins, and downregulating the expression of fission proteins. However, the therapeutic effect of EA on cognition in APP/PS1 mice was hindered by AMPKα1 knockout.

CONCLUSION

The regulation of hippocampal mitochondrial dynamics and reduction in Aβ deposition via the AMPK/PGC-1α pathway are critical for the ability of EA to ameliorate cognitive impairment in APP/PS1 mice. Please cite this article as: Jia WW, Lin HW, Yang MG, Dai YL, Ding YY, Xu WS, Wang SN, Cao YJ, Liang SX, Wang ZF, Chen C, Liu WL. Electroacupuncture activates AMPKα1 to improve learning and memory in the APP/PS1 mouse model of early Alzheimer's disease by regulating hippocampal mitochondrial dynamics. J Integr Med. 2024; 22(5): 588-599.

Alleviating neuronal inflammation induced by Aβ42 in SH-SY5Y through interaction with polysialic acid-oligomannuronate conjugate

Amyloid beta (Aβ) aggregation is one of the distinctive pathological hallmarks of Alzheimer's disease (AD). Therefore, the development of effective inhibitors against Aβ aggregate formation offers great promise for the treatment of AD. In this study, we designed a novel negatively charged functionalized conjugate aimed at inhibiting Aβ42 aggregation and attenuating neurotoxicity by grafting polysialic acid with mannuronate oligosaccharide, a biocompatible glycan extracted from seaweeds, designated as polysialic acid-mannan conjugate (PSA-MOS). ThT, biological microscopy, TEM and CD confirmed the inhibition of Aβ42 aggregation by PSA-MOS, as well as its ability to inhibit the conformational transition of Aβ42 to β-sheet. CCK-8 assay demonstrated that PSA-MOS was not cytotoxic to SH-SY5Y (p < 0.05) and promoted cell proliferation. In the Aβ42-induced SH-SY5Y injury models, PSA-MOS dose-dependently ameliorated cytotoxicity (p < 0.0001) and significantly reduced the levels of inflammatory factors of IL-1β (p < 0.0001), IL-6 (p < 0.0001) and TNF-α (p < 0.05). MD simulations demonstrated that PSA-MOS effectively impeded the α-helix to β-sheet transition of the Aβ42 monomer via electrostatic interactions with its CTR and NTR regions. These findings demonstrate the therapeutic potential of PSA-MOS as promising glycoconjugate for the treatment of AD.

Radiation-Induced Cognitive Decline: Challenges and Solutions

Radiation therapy, a common treatment for central nervous system cancers, can negatively impact cognitive function, resulting in radiation-induced cognitive decline (RICD). RICD involves a decline in cognitive abilities such as memory and attention, likely due to damage to brain white matter, inflammation, and oxidative stress. The multifactorial nature of RICD poses challenges including different mechanisms of injury (neurogenesis, oxidative stress and neuroinflammation, dendritic structure alterations and vascular effects) and confounding factors like advanced age, and pre-existing conditions. Despite these challenges, several potential solutions exist. Neuroprotective agents like antioxidants can mitigate radiation damage, while cognitive rehabilitation techniques such as cognitive training and memory strategies improve cognitive function. Advanced imaging techniques like magnetic resonance imaging (MRI) help identify vulnerable brain areas, and proton therapy offers precise targeting of cancer cells, sparing healthy tissue. Multidisciplinary care teams are crucial for managing RICD's cognitive and psychological effects. Personalized medicine, using genetic and molecular data, can identify high-risk patients and tailor treatments accordingly. Emerging therapies, including stem cell therapy and regenerative medicine, offer hope for repairing or replacing damaged brain tissue. Addressing RICD is vital for cancer survivors, necessitating consideration of cognitive function and provision of appropriate support and resources for those experiencing cognitive decline.

Single-Nucleus Landscape of Glial Cells and Neurons in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disease with a projected significant increase in incidence. Therefore, this study analyzed single-nucleus AD data to provide a theoretical basis for the clinical development and treatment of AD. We downloaded AD-related monocyte data from the Gene Expression Omnibus database, annotated cells, compared cell abundance between groups, and investigated glial and neuronal cell biological processes and pathways through functional enrichment analysis. Furthermore, we constructed a global regulatory network for AD based on cell communication and ecological analyses. Our findings revealed increased abundance of Capping Protein Regulator And Myosin 1 linker 1 (CARMIL1)+ astrocytes (AST), Immunoglobulin Superfamily Member 21 (IGSF21)+ microglia (MIC), SRY-Box Transcription Factor 6 (SOX6)+ inhibitory neurons (InNeu), and laminin alpha-2 chain (LAMA2)+ oligodendrocytes (OLI) cell subgroups in tissues of patients with AD, while prostaglandin D2 synthase (PTGDS)+ AST, Src Family Tyrosine Kinase (FYN)+ MIC, and Proteolipid Protein 1 (PLP1)+ InNeu subgroups specifically decreased. We found that the cell phenotype of patients with AD shifted from a simpler to a more complex state compared to the control group. Cell communication analysis revealed strong communication between MIC and NEU. Furthermore, AST, MIC, NEU, and OLI were involved in oxidative stress- and inflammation-related pathways, potentially contributing to disease development. This study provides a theoretical basis for further exploring the specific mechanisms underlying AD.

Direct and Rapid Visualization of the Spatial Distribution of Cholesterol in Alzheimer's and Cancer Tissue via MALDI Mass Spectrometry Imaging

Cholesterol is a vital component of the central nervous system and tissues, and understanding its spatial distribution is crucial for biology, pathophysiology, and diagnostics. However, direct imaging of cholesterol using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) remains challenging and time-consuming due to the difficulty in ionizing the sterol molecule. To tackle this issue, a MALDI-MSI method is established for direct and rapid analysis of the spatial distribution of cholesterol in Alzheimer's disease (AD), different cancer tissues and organs via MALDI-MSI. This excellent imaging performance depends on the study and systemic optimization of various conditions that affect the imaging of MALDI-MSI. In this case, we report the distribution and levels of cholesterol across specific structures of the AD mouse brain and different tumor tissue and organs. According to the results, the content of cholesterol in the AD mouse cerebellum, especially in the arborvitae, was significantly higher than that in the wild type (WT) model. Furthermore, we successfully visualize the distribution of cholesterol in other organs, such as the heart, liver, spleen, kidney, pancreas, as well as tumor tissues parenchyma and interstitium using MALDI-MSI. Notably, the attribution of cholesterol MS/MS hydrocarbon fragments was systematically investigated. Our presented optimization strategy and established MALDI-MSI method can be easily generalized for different animal tissues or live samples, thereby facilitating the potential for applications of MALDI-MSI in clinical, medical and biological research.

Electroacupuncture Improves Learning and Memory Abilities via Activating AMPK/mTOR-Induced Autophagy in APP/PS1 Mice

Alzheimer's disease (AD) has become a global public health problem characterized by memory and cognitive impairments. Electroacupuncture (EA) has been indicated to exert promising therapeutic effects on AD. This study aimed to further investigate the underlying mechanism of EA in AD treatment. APP/PS1 transgenic mice and wide-type mice underwent with or without EA treatment at GV20 and BL23 acupoints. Morris water maze test was utilized for examining the learning and memory of mice. Hematoxylin-eosin, Congo red, immunofluorescence, and TUNEL staining were employed for detecting the pathological changes of mouse brain hippocampus. Western blotting was implemented for measuring protein levels of autophagy- and AMPK/mTOR pathway-associated markers. APP/PS1 mice exhibited significant impairments in the spatial learning and memory. EA treatment improved the cognitive impairments, reduced amyloid-beta (Aβ) deposition, and alleviated neuronal apoptosis in the hippocampal tissues of APP/PS1 mice. EA promoted autophagy and activated the AMPK/mTOR signaling pathway in the hippocampus of APP/PS1 mice. EA improves the cognitive deficits, enhances Aβ clearance, and attenuates neuronal apoptosis in APP/PS1 mice in part by activating AMPK/mTOR-mediated autophagy.

Single-nucleus multiomics reveals the disrupted regulatory programs in three brain regions of sporadic early-onset Alzheimer's disease

Sporadic early-onset Alzheimer's disease (sEOAD) represents a significant but less-studied subtype of Alzheimer's disease (AD). Here, we generated a single-nucleus multiome atlas derived from the postmortem prefrontal cortex, entorhinal cortex, and hippocampus of nine individuals with or without sEOAD. Comprehensive analyses were conducted to delineate cell type-specific transcriptomic changes and linked candidate cis-regulatory elements (cCREs) across brain regions. We prioritized seven conservative transcription factors in glial cells in multiple brain regions, including RFX4 in astrocytes and IKZF1 in microglia, which are implicated in regulating sEOAD-associated genes. Moreover, we identified the top 25 altered intercellular signaling between glial cells and neurons, highlighting their regulatory potential on gene expression in receiver cells. We reported 38 cCREs linked to sEOAD-associated genes overlapped with late-onset AD risk loci, and sEOAD cCREs enriched in neuropsychiatric disorder risk loci. This atlas helps dissect transcriptional and chromatin dynamics in sEOAD, providing a key resource for AD research.

Can exercise benefits be harnessed with drugs? A new way to combat neurodegenerative diseases by boosting neurogenesis

Adult hippocampal neurogenesis (AHN) is affected by multiple factors, such as enriched environment, exercise, ageing, and neurodegenerative disorders. Neurodegenerative disorders can impair AHN, leading to progressive neuronal loss and cognitive decline. Compelling evidence suggests that individuals engaged in regular exercise exhibit higher production of proteins that are essential for AHN and memory. Interestingly, specific molecules that mediate the effects of exercise have shown effectiveness in promoting AHN and cognition in different transgenic animal models. Despite these advancements, the precise mechanisms by which exercise mimetics induce AHN remain partially understood. Recently, some novel exercise molecules have been tested and the underlying mechanisms have been proposed, involving intercommunications between multiple organs such as muscle-brain crosstalk, liver-brain crosstalk, and gut-brain crosstalk. In this review, we will discuss the current evidence regarding the effects and potential mechanisms of exercise mimetics on AHN and cognition in various neurological disorders. Opportunities, challenges, and future directions in this research field are also discussed.

The influence of Black Cohosh on hippocampal and hypothalamic gene expression profiles in ovariectomized rats and its potential to treat menopausal decrease in smell discrimination

PURPOSE

Menopause is associated with a decrease in smell discrimination ability. This study assessed the impact of black cohosh on hippocampal (HC) and hypothalamic (HT) gene expression profiles in rats, to understand, if herbal treatment has an impact on neurologic changes due to menopause and whether this could address a decrease in smell discrimination.

METHODS

HC and HT tissues from female Sprague Dawley rats (total n = 19) were analyzed at three different life stages: intact tissues of the HC (n = 4) and the HT (n = 4), oophorectomized tissues 3 months after oophorectomy (OVX) of the HC (n = 4) and the HT (n = 3), and tissues after treatment with an isopropanolic extract (iCR) from the rhizomes of black cohosh (60 mg/kg) for 3 months after OVX of the HC (n = 2) and the HT (n = 2).

MAIN OUTCOME MEASURES

To reveal underlying biological processes a gene set enrichment analysis (GSEA) was performed.

RESULTS

The GSEA revealed gene ontology terms that were significantly enriched, including several genes associated with the olfactory system, indicating biological processes regulated by treatment with iCR. Six olfactory receptor genes were further analyzed by another GSEA, demonstrating the possibility of iCR treatment to compensate for oophorectomy-induced changes.

CONCLUSION

Findings suggest that herbal treatment, such as iCR, has an esteeming impact on HC and HT genes that are changed through menopause. Further studies are needed to suggest black cohosh as a treatment option for decreased smell discrimination.

Acylhydrazone Derivative A5 Promotes Neurogenesis by Up-Regulating Neurogenesis-Related Genes and Inhibiting Cell-Cycle Progression in Neural Stem/Progenitor Cells

Adult neurogenesis involves the generation of functional neurons from neural progenitor cells, which have the potential to complement and restore damaged neurons and neural circuits. Therefore, the development of drugs that stimulate neurogenesis represents a promising strategy in stem cell therapy and neural regeneration, greatly facilitating the reconstruction of neural circuits in cases of neurodegeneration and brain injury. Our study reveals that compound A5, previously designed and synthesized by our team, exhibits remarkable neuritogenic activities, effectively inducing neurogenesis in neural stem/progenitor cells (NSPCs). Subsequently, transcriptome analysis using high-throughput Illumina RNA-seq technology was performed to further elucidate the underlying molecular mechanisms by which Compound A5 promotes neurogenesis. Notably, comparative transcriptome analysis showed that the up-regulated genes were mainly associated with neurogenesis, and the down-regulated genes were mainly concerned with cell cycle progression. Furthermore, we confirmed that Compound A5 significantly affected the expression of transcription factors related to neurogenesis and cell cycle regulatory proteins. Collectively, these findings identify a new compound with neurogenic activity and may provide insights into drug discovery for neural repair and regeneration.

Exploring the multifaceted therapeutic mechanism of Schisanlactone E (XTS) in APP/PS1 mouse model of Alzheimer's disease through multi-omics analysis

Background

Schisanlactone E, also known as XueTongSu (XTS), is an active compound extracted from the traditional Tujia medicine Kadsura heteroclita ("XueTong"). Recent studies highlight its anti-inflammatory and antioxidant properties, yet the mechanisms of XTS's therapeutic effects on Alzheimer's disease (AD) are unclear. This study aims to elucidate the therapeutic efficacy and mechanisms of XTS in AD.

Methods

Ten C57BL/6 mice were assigned to the control group (NC), and twenty APP/PS1 transgenic mice were randomly divided into the model group (M) (10 mice) and the XTS treatment group (Tre) (10 mice). After an acclimatization period of 7 days, intraperitoneal injections were administered over a 60-day treatment period. The NC and M groups received saline, while the Tre group received XTS at 2 mg/kg. Learning and memory abilities were assessed using the Morris Water Maze (MWM) test. Histopathological changes were evaluated using hematoxylin and eosin (HE) and Nissl staining, and immunofluorescence was used to assess pathological products and glial cell activation. Cytokine levels (IL-1β, IL-6, TNF-α) in the hippocampus were quantified by qPCR. 16S rDNA sequencing analyzed gut microbiota metabolic alterations, and metabolomic analysis was performed on cortical samples. The KEGG database was used to analyze the regulatory mechanisms of XTS in AD treatment.

Results

XTS significantly improved learning and spatial memory in APP/PS1 mice and ameliorated histopathological changes, reducing Aβ plaque aggregation and glial cell activation. XTS decreased the expression of inflammatory cytokines IL-1β, IL-6, and TNF-α. It also enhanced gut microbiota diversity, notably increasing Akkermansia species, and modulated levels of metabolites such as isosakuranetin, 5-KETE, 4-methylcatechol, and sphinganine. Pathway analysis indicated that XTS regulated carbohydrate metabolism, neuroactive ligand-receptor interactions, and alanine, aspartate, and glutamate metabolism, mitigating gut microbiota dysbiosis and metabolic disturbances.

Conclusion

XTS ameliorates cognitive deficits, pathological changes, and inflammatory responses in APP/PS1 mice. It significantly modulates the gut microbiota, particularly increasing Akkermansia abundance, and influences levels of key metabolites in both the gut and brain. These findings suggest that XTS exerts anti-AD effects through the microbial-gut-brain axis (MGBA).

Ovomemolins: Egg-derived peptides that improved cognitive decline after oral administration in mice

Eggs not only contain all the molecules necessary to nurture new life but are also rich in nutrients such as high-quality protein. For example, epidemiologic studies have shown that egg intake is positively correlated with cognitive function. Thus, we specifically examined the effect of ovalbumin, a major protein present in egg whites, on cognitive function. First, we found that an orally administered enzymatic digest of ovalbumin improves cognitive function in mice fed a high-fat diet. Then, we narrowed down candidate peptides based on the prediction of peptide production according to enzyme-substrate specificity and comprehensive peptide analysis of the digest. We found that three peptides, namely ILPEY, LYRGGLEP, and ILELP, improve cognitive function after oral administration. We also showed that ILPEY, LYRGGLEP, and ILELP were present in the digest and named them ovomemolins A (OMA), B, and C, respectively. Notably, ovomemolins are the first peptides derived from egg whites that have been shown to improve cognitive function. The cognitive improvement induced by OMA, the most abundant of the peptides in the digest, was inhibited by methyllycaconitine, an antagonist of α7nAChR, which is known to be related to memory. These results suggest that OMA improves cognitive function through the acetylcholine system. After OMA administration, brain-derived neurotrophic factor (BDNF) mRNA expression and the number of 5-bromo-2'-deoxyuridine-positive cells suggested that OMA increases hippocampal BDNF expression and neurogenesis.

Single-nucleus multiomics reveals the disrupted regulatory programs in three brain regions of sporadic early-onset Alzheimer's disease

Sporadic early-onset Alzheimer's disease (sEOAD) represents a significant but less-studied subtype of Alzheimer's disease (AD). Here, we generated a single-nucleus multiome atlas derived from the postmortem prefrontal cortex, entorhinal cortex, and hippocampus of nine individuals with or without sEOAD. Comprehensive analyses were conducted to delineate cell type-specific transcriptomic changes and linked candidate cis- regulatory elements (cCREs) across brain regions. We prioritized seven conservative transcription factors in glial cells in multiple brain regions, including RFX4 in astrocytes and IKZF1 in microglia, which are implicated in regulating sEOAD-associated genes. Moreover, we identified the top 25 altered intercellular signaling between glial cells and neurons, highlighting their regulatory potential on gene expression in receiver cells. We reported 38 cCREs linked to sEOAD-associated genes overlapped with late-onset AD risk loci, and sEOAD cCREs enriched in neuropsychiatric disorder risk loci. This atlas helps dissect transcriptional and chromatin dynamics in sEOAD, providing a key resource for AD research.

Evaluating frontoparietal network topography for diagnostic markers of Alzheimer's disease

Numerous prospective biomarkers are being studied for their ability to diagnose various stages of Alzheimer's disease (AD). High-density electroencephalogram (EEG) methods show promise as an accurate, economical, non-invasive approach to measuring the electrical potentials of brains associated with AD. Event-related potentials (ERPs) may serve as clinically useful biomarkers of AD. Through analysis of secondary data, the present study examined the performance and distribution of N4/P6 ERPs across the frontoparietal network (FPN) using EEG topographic mapping. ERP measures and memory as a function of reaction time (RT) were compared between a group of (n = 63) mild untreated AD patients and a control group of (n = 73) healthy age-matched adults. Based on the literature presented, it was expected that healthy controls would outperform patients in peak amplitude and mean component latency across three parameters of memory when measured at optimal N4 (frontal) and P6 (parietal) locations. It was also predicted that the control group would exhibit neural cohesion through FPN integration during cross-modal tasks, thus demonstrating healthy cognitive functioning consistent with older healthy adults. By targeting select frontal and parietal EEG reference channels based on N4/P6 component time windows and positivity, our findings demonstrated statistically significant group variations between controls and patients in N4/P6 peak amplitudes and latencies during cross-modal testing. Our results also support that the N4 ERP might be stronger than its P6 counterpart as a possible candidate biomarker. We conclude through topographic mapping that FPN integration occurs in healthy controls but is absent in AD patients during cross-modal memory tasks.

Environmental enrichment: a systematic review on the effect of a changing spatial complexity on hippocampal neurogenesis and plasticity in rodents, with considerations for translation to urban and built environments for humans

Introduction

Hippocampal neurogenesis is critical for improving learning, memory, and spatial navigation. Inhabiting and navigating spatial complexity is key to stimulating adult hippocampal neurogenesis (AHN) in rodents because they share similar hippocampal neuroplasticity characteristics with humans. AHN in humans has recently been found to persist until the tenth decade of life, but it declines with aging and is influenced by environmental enrichment. This systematic review investigated the impact of spatial complexity on neurogenesis and hippocampal plasticity in rodents, and discussed the translatability of these findings to human interventions.

Methods

Comprehensive searches were conducted on three databases in English: PubMed, Web of Science, and Scopus. All literature published until December 2023 was screened and assessed for eligibility. A total of 32 studies with original data were included, and the process is reported in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and checklist.

Results

The studies evaluated various models of spatial complexity in rodents, including environmental enrichment, changes to in-cage elements, complex layouts, and navigational mazes featuring novelty and intermittent complexity. A regression equation was formulated to synthesize key factors influencing neurogenesis, such as duration, physical activity, frequency of changes, diversity of complexity, age, living space size, and temperature.

Conclusion

Findings underscore the cognitive benefits of spatial complexity interventions and inform future translational research from rodents to humans. Home-cage enrichment and models like the Hamlet complex maze and the Marlau cage offer insight into how architectural design and urban navigational complexity can impact neurogenesis in humans. In-space changing complexity, with and without physical activity, is effective for stimulating neurogenesis. While evidence on intermittent spatial complexity in humans is limited, data from the COVID-19 pandemic lockdowns provide preliminary evidence. Existing equations relating rodent and human ages may allow for the translation of enrichment protocol durations from rodents to humans.

Hippocampal mitophagy contributes to spatial memory via maintaining neurogenesis during the development of mice

BACKGROUND

Impaired mitochondrial dynamics have been identified as a significant contributing factor to reduced neurogenesis under pathological conditions. However, the relationship among mitochondrial dynamics, neurogenesis, and spatial memory during normal development remains unclear. This study aims to elucidate the role of mitophagy in spatial memory mediated by neurogenesis during development.

METHODS

Adolescent and adult male mice were used to assess spatial memory performance. Immunofluorescence staining was employed to evaluate levels of neurogenesis, and mitochondrial dynamics were assessed through western blotting and transmission electron microscopy. Pharmacological interventions further validated the causal relationship among mitophagy, neurogenesis, and behavioral performance during development.

RESULTS

The study revealed differences in spatial memory between adolescent and adult mice. Diminished neurogenesis, accompanied by reduced mitophagy, was observed in the hippocampus of adult mice compared to adolescent subjects. Pharmacological induction of mitophagy in adult mice with UMI-77 resulted in enhanced neurogenesis and prolonged spatial memory retention. Conversely, inhibition of mitophagy with Mdivi-1 in adolescent mice led to reduced hippocampal neurogenesis and impaired spatial memory.

CONCLUSION

The observed decline in spatial memory in adult mice is associated with decreased mitophagy, which affects neurogenesis in the dentate gyrus. This underscores the therapeutic potential of enhancing mitophagy to counteract age- or disease-related cognitive decline.

Brain structural covariances in the ageing brain in the UK Biobank

The morphologic properties of brain regions co-vary or correlate with each other. Here we investigated the structural covariances of cortical thickness and subcortical volumes in the ageing brain, along with their associations with age and cognition, using cross-sectional data from the UK Biobank (N = 42,075, aged 45-83 years, 53% female). As the structural covariance should be estimated in a group of participants, all participants were divided into 84 non-overlapping, equal-sized age groups ranging from the youngest to the oldest. We examined 84 cortical thickness covariances and subcortical covariances. Our findings include: (1) there were significant differences in the variability of structural covariance in the ageing process, including an increased variance, and a decreased entropy. (2) significant enrichment in pairwise correlations between brain regions within the occipital lobe was observed in all age groups; (3) structural covariance in older age, especially after the age of around 64, was significantly different from that in the youngest group (median age 48 years); (4) sixty-two of the total 528 pairs of cortical thickness correlations and 10 of the total 21 pairs of subcortical volume correlations showed significant associations with age. These trends varied, with some correlations strengthening, some weakening, and some reversing in direction with advancing age. Additionally, as ageing was associated with cognitive decline, most of the correlations with cognition displayed an opposite trend compared to age associated patterns of correlations.

Lancao decoction alleviates cognitive dysfunction: A new therapeutic drug and its therapeutic mechanism

BACKGROUND

Cognitive dysfunction (CD) is a neurodegenerative disease characterized primarily by the decline of learning and memory abilities. The physiological and pathological mechanisms of CD are very complex, which is mainly related to normal function of the hippocampus. Lancao decoction (LC) is a Chinese medicine formula, which has been used to treat neurodegenerative disorders. However, the potential of LC for the treatment of CD, as well as its underlying mechanisms, is unclear.

PURPOSE

In the study, we aimed to reveal the functional and neuronal mechanisms of LC's treatments for CD in scopolamine-induced mice.

METHODS

Gas chromatography (GC) was used to determine the stability of LC's extraction. CD model was established by the chronic induction of scopolamine (Scop, 1 mg/kg/day) for 1 week. Behavioral tests including morris water maze (MWM) and y-maze were used to evaluate learning and memory abilities of mice after LC's treatments. Immunofluorescence was used to detected the expressions of cFOS, Brdu and Ki67 after LC's treatments. Pharmacological blockade experiments explored the role of α-Amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) in LC's treatments for CD and its relationships with regeneration, activities and differentiation of neurons.

RESULTS

The results showed that LC was capable of improving spatial learning and memory and spontaneous alternating abilities in Scop-induced mice, which was similar to donepezil. LC could increase the number of cFOS positive cells, which was used as a marker of neuronal activity to upregulate by neuronal activities in hippocampus, but donepezil did not. Moreover, LC could strengthen neurogenesis and neuro-differentiation by increasing the number of Brdu and Ki67 positive cells in hippocampal dentate gyrus (DG), meanwhile, donepezil could only enhance the number of Ki67 positive cells. Transient inhibition of AMPAR by NBQX blunted the function of LC's treatment for CD and inhibited the enhanced effect of LC on Scop-induced hippocampal neuronal excitability and neurogenesis in mice.

CONCLUSION

To sum up, our study demonstrated that LC had the function of treating CD by enhancing content of acetylcholine (ACh) to activate AMPAR, which further up-regulated neurogenesis and neuronal differentiation to strengthen neuroactivities in hippocampus.

Emerging Pro-neurogenic Therapeutic Strategies for Neurodegenerative Diseases: A Review of Pre-clinical and Clinical Research

The neuroscience community has largely accepted the notion that functional neurons can be generated from neural stem cells in the adult brain, especially in two brain regions: the subventricular zone of the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus. However, impaired neurogenesis has been observed in some neurodegenerative diseases, particularly in Alzheimer's, Parkinson's, and Huntington's diseases, and also in Lewy Body dementia. Therefore, restoration of neurogenic function in neurodegenerative diseases emerges as a potential therapeutic strategy to counteract, or at least delay, disease progression. Considering this, the present study summarizes the different neuronal niches, provides a collection of the therapeutic potential of different pro-neurogenic strategies in pre-clinical and clinical research, providing details about their possible modes of action, to guide future research and clinical practice.

Learning semi-supervised enrichment of longitudinal imaging-genetic data for improved prediction of cognitive decline

BACKGROUND

Alzheimer's Disease (AD) is a progressive memory disorder that causes irreversible cognitive decline. Given that there is currently no cure, it is critical to detect AD in its early stage during the disease progression. Recently, many statistical learning methods have been presented to identify cognitive decline with temporal data, but few of these methods integrate heterogeneous phenotype and genetic information together to improve the accuracy of prediction. In addition, many of these models are often unable to handle incomplete temporal data; this often manifests itself in the removal of records to ensure consistency in the number of records across participants.

RESULTS

To address these issues, in this work we propose a novel approach to integrate the genetic data and the longitudinal phenotype data to learn a fixed-length "enriched" biomarker representation derived from the temporal heterogeneous neuroimaging records. Armed with this enriched representation, as a fixed-length vector per participant, conventional machine learning models can be used to predict clinical outcomes associated with AD.

CONCLUSION

The proposed method shows improved prediction performance when applied to data derived from Alzheimer's Disease Neruoimaging Initiative cohort. In addition, our approach can be easily interpreted to allow for the identification and validation of biomarkers associated with cognitive decline.

β-Hexachlorocyclohexane triggers neuroinflammatory activity, epigenetic histone post-translational modifications and cognitive dysfunction

Persistent organic pollutants (POPs), which encompass pesticides and industrial chemicals widely utilized across the globe, pose a covert threat to human health. β-hexachlorocyclohexane (β-HCH) is an organochlorine pesticide with striking stability, still illegally dumped in many countries, and recognized as responsible for several pathogenetic mechanisms. This study represents a pioneering exploration into the neurotoxic effects induced by the exposure to β-HCH specifically targeting neuronal cells (N2a), microglia (BV-2), and C57BL/6 mice. As shown by western blot and qPCR analyses, the administration of β-HCH triggered a modulation of NF-κB, a key factor influencing both inflammation and pro-inflammatory cytokines expression. We demonstrated by proteomic and western blot techniques epigenetic modifications in H3 histone induced by β-HCH. Histone acetylation of H3K9 and H3K27 increased in N2a, and in the prefrontal cortex of C57BL/6 mice administered with β-HCH, whereas it decreased in BV-2 cells and in the hippocampus. We also observed a severe detrimental effect on recognition memory and spatial navigation by the Novel Object Recognition Test (NORT) and the Object Place Recognition Task (OPRT) behavioural tests. Cognitive impairment was linked to decreased expression of the genes BDNF and SNAP-25, which are mediators involved in synaptic function and activity. The obtained results expand our understanding of the harmful impact produced by β-HCH exposure by highlighting its implication in the pathogenesis of neurological diseases. These findings will support intervention programs to limit the risk induced by exposure to POPs. Regulatory agencies should block further illicit use, causing environmental hazards and endangering human and animal health.

Oxytocin attenuates hypothalamic injury-induced cognitive dysfunction by inhibiting hippocampal ERK signaling and Aβ deposition

In clinical settings, tumor compression, trauma, surgical injury, and other types of injury can cause hypothalamic damage, resulting in various types of hypothalamic dysfunction. Impaired release of oxytocin can lead to cognitive impairment and affect prognosis and long-term quality of life after hypothalamic injury. Hypothalamic injury-induced cognitive dysfunction was detected in male animals. Behavioral parameters were measured to assess the characteristics of cognitive dysfunction induced by hypothalamic-pituitary stalk lesions. Brains were collected for high-throughput RNA sequencing and immunostaining to identify pathophysiological changes in hippocampal regions highly associated with cognitive function after injury to corresponding hypothalamic areas. Through transcriptomic analysis, we confirmed the loss of oxytocin neurons after hypothalamic injury and the reversal of hypothalamic-induced cognitive dysfunction after oxytocin supplementation. Furthermore, overactivation of the ERK signaling pathway and β-amyloid deposition in the hippocampal region after hypothalamic injury were observed, and cognitive function was restored after inhibition of ERK signaling pathway overactivation. Our findings suggest that cognitive dysfunction after hypothalamic injury may be caused by ERK hyperphosphorylation in the hippocampal region resulting from a decrease in the number of oxytocin neurons, which in turn causes β-amyloid deposition.

Photobiomodulation in experimental models of Alzheimer's disease: state-of-the-art and translational perspectives

Alzheimer's disease (AD) poses a significant public health problem, affecting millions of people across the world. Despite decades of research into therapeutic strategies for AD, effective prevention or treatment for this devastating disorder remains elusive. In this review, we discuss the potential of photobiomodulation (PBM) for preventing and alleviating AD-associated pathologies, with a focus on the biological mechanisms underlying this therapy. Future research directions and guidance for clinical practice for this non-invasive and non-pharmacological therapy are also highlighted. The available evidence indicates that different treatment paradigms, including transcranial and systemic PBM, along with the recently proposed remote PBM, all could be promising for AD. PBM exerts diverse biological effects, such as enhancing mitochondrial function, mitigating the neuroinflammation caused by activated glial cells, increasing cerebral perfusion, improving glymphatic drainage, regulating the gut microbiome, boosting myokine production, and modulating the immune system. We suggest that PBM may serve as a powerful therapeutic intervention for AD.

The Therapeutic Potential of Harpagophytum procumbens and Turnera subulata and Advances in Nutraceutical Delivery Systems in Neurodegenerative Diseases

This review article covers the therapeutic potential of the plants Harpagophytum procumbens and Turnera subulata in the treatment of neurodegenerative diseases. Despite the recognition of their beneficial properties, there is notable shortage of specific clinical and in vitro studies on these species regarding neurodegenerative diseases. Compounds such as harpagosides and vite-xin-2-O-rhamnoside, found in Harpagophytum procumbens and Turnera subulata, respectively, as well as other antioxidants and anti-inflammatory agents, are associated with mechanisms of action that involve reducing oxidative stress and modulating the inflammatory response, indicating their therapeutic potential in these pathologies. Additionally, the use of nutraceuticals derived from medicinal plants has emerged as a promising approach, offering natural therapeutic alternatives. However, the pressing need for studies focusing on the pharmacokinetics, safety, and pharmacological interactions of these extracts for the treatment of neurodegenerative diseases is emphasized. This review also evaluated advances in nutraceutical delivery systems, highlighting technological innovations that can optimize the precise delivery of these compounds to patients. Such findings highlight the gaps in the study of these plants for the treatment of neurodegenerative diseases and, at the same time, the potential for opening new perspectives in the treatment of neurodegenerative diseases, providing expectations for innovative solutions in this critical domain of medicine.

Exploring the neuropharmacological potential of empagliflozin on nootropic and scopolamine-induced amnesic model of Alzheimer's like conditions in rats

BACKGROUND

Alzheimer's disease (AD) is one of the most challenging and prevalent neurodegenerative disorder globally with a rising prevalence, characterized by progressive cognitive decline, memory loss, and behavioural changes. Current research aims to determine the nootropic and anti-amnesic effect of Empagliflozin (EMPA) against scopolamine-induced amnesia in rats, by modulating the cholinergic and N-Methyl D-Aspartate (NMDA) receptors.

METHODS

Rats were treated once daily with an EMPA (5 and 10 mg/kg) and donepezil (2.5 mg/kg) for successive 26 days. During the final 13 days of treatment, a daily injection of scopolamine (1 mg/kg) was administered to induce cognitive deficits.

RESULTS

EMPA was found to be significantly reduce escape latency, increase time spent in the target quadrant, and enhanced the number of target zone crossings in the Morris water maze (MWM) test, indicating improved spatial memory. Moreover, EMPA increased the recognition index and the number of spontaneous alternations in the novel object recognition (NOR) and Y-maze tests, respectively, suggesting enhanced memory.

DISCUSSION

Interestingly doses of EMPA (5 mg/kg, 10 mg/kg) exhibited memory-enhancing effects even in the absence of scopolamine-induced impairment. Biochemical analysis revealed that EMPA elevated the levels of glutathione (GSH), a potent antioxidant, while decreasing lipid peroxidation (LPO) activity and increasing catalase (CAT) levels, indicating its antioxidative properties. Interestingly molecular docking studies revealed that EMPA fit perfectly in the active sites of M1 muscarinic acetylcholine (mACh) and NMDA receptors. These results indicated that the nootropic and antiamnesic effect of EMPA is possibly mediated via M1 and NMDA receptors and might be a remedy for AD.

Abdominal fat depots are related to lower cognitive functioning and brain volumes in middle-aged males at high Alzheimer's risk

OBJECTIVE

High BMI, which poorly represents specific fat depots, is linked to poorer cognition and higher dementia risk, with different associations between sexes. This study examined associations of abdominal fat depots with cognition and brain volumes and whether sex modifies this association.

METHODS

A total of 204 healthy middle-aged offspring of Alzheimer's dementia patients (mean age = 59.44, 60% females) underwent abdominal magnetic resonance imaging to quantify hepatic, pancreatic, visceral, and subcutaneous adipose tissue and to assess cognition and brain volumes.

RESULTS

In the whole sample, higher hepatic fat percentage was associated with lower total gray matter volume (β = -0.17, p < 0.01). Primarily in males, higher pancreatic fat percentage was associated with lower global cognition (males: β = -0.27, p = 0.03; females: β = 0.01, p = 0.93) executive function (males: β = -0.27, p = 0.03; females: β = 0.02, p = 0.87), episodic memory (males: β = -0.28, p = 0.03; females: β = 0.07, p = 0.48), and inferior frontal gyrus volume (males: β = -0.28, p = 0.02; females: β = 0.10, p = 0.33). Visceral and subcutaneous adipose tissue was inversely associated with middle frontal and superior frontal gyrus volumes in males and females.

CONCLUSIONS

In middle-aged males at high Alzheimer's dementia risk, but not in females, higher pancreatic fat was associated with lower cognition and brain volumes. These findings suggest a potential sex-specific link between distinct abdominal fat with brain health.

Constructing hierarchical attentive functional brain networks for early AD diagnosis

Analyzing functional brain networks (FBN) with deep learning has demonstrated great potential for brain disorder diagnosis. The conventional construction of FBN is typically conducted at a single scale with a predefined brain region atlas. However, numerous studies have identified that the structure and function of the brain are hierarchically organized in nature. This urges the need of representing FBN in a hierarchical manner for more effective analysis of the complementary diagnostic insights at different scales. To this end, this paper proposes to build hierarchical FBNs adaptively within the Transformer framework. Specifically, a sparse attention-based node-merging module is designed to work alongside the conventional network feature extraction modules in each layer. The proposed module generates coarser nodes for further FBN construction and analysis by combining fine-grained nodes. By stacking multiple such layers, a hierarchical representation of FBN can be adaptively learned in an end-to-end manner. The hierarchical structure can not only integrate the complementary information from multiscale FBN for joint analysis, but also reduce the model complexity due to decreasing node sizes. Moreover, this paper argues that the nodes defined by the existing atlases are not necessarily the optimal starting level to build FBN hierarchy and exploring finer nodes may further enrich the FBN representation. In this regard, each predefined node in an atlas is split into multiple sub-nodes, overcoming the scale limitation of the existing atlases. Extensive experiments conducted on various data sets consistently demonstrate the superior performance of the proposed method over the competing methods.

Identifying candidate genes associated with hippocampal dysfunction in a hemiparkinsonian rat model by transcriptomic profiling

Parkinson's disease (PD) often results in hippocampal dysfunction, which leads to cognitive and emotional challenges and synaptic irregularities. This study attempted to assess behavioral anomalies and identify differentially expressed genes (DEGs) within the hippocampus of a hemiparkinsonian rat model to potentially uncover novel genetic candidates linked to hippocampal dysfunction. Striatal 6-hydroxydopamine (6-OHDA) infusions were performed unilaterally in the brains of adult SD rats, while dopaminergic impairments were verified in rats with 6-OHDA-lesioned striata. RNA sequencing and gene expression analysis unveiled 1018 DEGs in the ipsilateral rat hippocampus following 6-OHDA infusion: 631 genes exhibited upregulation, while 387 genes were downregulated (with FDR-adjusted p-value < 0.05 and absolute fold-change > 1.5). Gene ontology analysis of DEGs indicated that alterations in the hippocampi of 6-OHDA-lesioned rats were primarily associated with synaptic signaling, axon development, behavior, postsynaptic membrane, synaptic membrane, neurotransmitter receptor activity, and peptide receptor activity. The Kyoto Encyclopedia of Genes and Genomes analysis of DEGs demonstrated significant enrichment of the neuroactive ligand-receptor interaction, calcium signaling pathway, cAMP signaling pathway, axon guidance, and notch signaling pathway in rat hippocampi that had been subjected to striatal 6-OHDA infusion. STRING analysis confirmed a notable upregulation of eight hub genes (Notch3, Gng4, Itga3, Grin2d, Hgf, Fgf11, Htr3a, and Col6a2), along with a significant downregulation of two hub genes (Itga11 and Plp1), as validated by reverse transcription-quantitative polymerase chain reaction. This study provides a comprehensive transcriptomic profile of the hippocampi in a hemiparkinsonian rat model, thereby offering insights into the signaling pathways underlying hippocampal dysfunction.

Bisphenol-F and Bisphenol-S (BPF and BPS) Impair the Stemness of Neural Stem Cells and Neuronal Fate Decision in the Hippocampus Leading to Cognitive Dysfunctions

Neurogenesis occurs throughout life in the hippocampus of the brain, and many environmental toxicants inhibit neural stem cell (NSC) function and neuronal generation. Bisphenol-A (BPA), an endocrine disrupter used for surface coating of plastic products causes injury in the developing and adult brain; thus, many countries have banned its usage in plastic consumer products. BPA analogs/alternatives such as bisphenol-F (BPF) and bisphenol-S (BPS) may also cause neurotoxicity; however, their effects on neurogenesis are still not known. We studied the effects of BPF and BPS exposure from gestational day 6 to postnatal day 21 on neurogenesis. We found that exposure to non-cytotoxic concentrations of BPF and BPS significantly decreased the number/size of neurospheres, BrdU+ (proliferating NSC marker) and MAP-2+ (neuronal marker) cells and GFAP+ astrocytes in the hippocampus NSC culture, suggesting reduced NSC stemness and self-renewal and neuronal differentiation and increased gliogenesis. These analogs also reduced the number of BrdU/Sox-2+, BrdU/Dcx+, and BrdU/NeuN+ co-labeled cells in the hippocampus of the rat brain, suggesting decreased NSC proliferation and impaired maturation of newborn neurons. BPF and BPS treatment increases BrdU/cleaved caspase-3+ cells and Bax-2 and cleaved caspase protein levels, leading to increased apoptosis in hippocampal NSCs. Transmission electron microscopy studies suggest that BPF and BPS also caused degeneration of neuronal myelin sheath, altered mitochondrial morphology, and reduced number of synapses in the hippocampus leading to altered cognitive functions. These results suggest that BPF and BPS exposure decreased the NSC pool, inhibited neurogenesis, induced apoptosis of NSCs, caused myelin degeneration/synapse degeneration, and impaired learning and memory in rats.

Aβ peptide enhances GluA1 internalization via lipid rafts in Alzheimer's-related hippocampal LTP dysfunction

Amyloid β (Aβ) is a central contributor to neuronal damage and cognitive impairment in Alzheimer's disease (AD). Aβ disrupts AMPA receptor-mediated synaptic plasticity, a key factor in early AD progression. Numerous studies propose that Aβ oligomers hinder synaptic plasticity, particularly long-term potentiation (LTP), by disrupting GluA1 (encoded by GRIA1) function, although the precise mechanism remains unclear. In this study, we demonstrate that Aβ mediates the accumulation of GM1 ganglioside in lipid raft domains of cultured cells, and GluA1 exhibits preferential localization in lipid rafts via direct binding to GM1. Aβ enhances the raft localization of GluA1 by increasing GM1 in these areas. Additionally, chemical LTP stimulation induces lipid raft-dependent GluA1 internalization in Aβ-treated neurons, resulting in reduced cell surface and postsynaptic expression of GluA1. Consistent with this, disrupting lipid rafts and GluA1 localization in rafts rescues Aβ-mediated suppression of hippocampal LTP. These findings unveil a novel functional deficit in GluA1 trafficking induced by Aβ, providing new insights into the mechanism underlying AD-associated cognitive dysfunction.

Kallikrein-related peptidase's significance in Alzheimer's disease pathogenesis: A comprehensive survey

Alzheimer's disease (AD) and related dementias constitute an important global health challenge. Detailed understanding of the multiple molecular mechanisms underlying their pathogenesis constitutes a clue for the management of the disease. Kallikrein-related peptidases (KLKs), a lead family of serine proteases, have emerged as potential biomarkers and therapeutic targets in the context of AD and associated cognitive decline. Hence, KLKs were proposed to display multifaceted impacts influencing various aspects of neurodegeneration, including amyloid-beta aggregation, tau pathology, neuroinflammation, and synaptic dysfunction. We propose here a comprehensive survey to summarize recent findings, providing an overview of the main kallikreins implicated in AD pathophysiology namely KLK8, KLK6 and KLK7. We explore the interplay between KLKs and key AD molecular pathways, shedding light on their significance as potential biomarkers for early disease detection. We also discuss their pertinence as therapeutic targets for disease-modifying interventions to develop innovative therapeutic strategies aimed at halting or ameliorating the progression of AD and associated dementias.

Effect of Cerebralcare Granule® combined with memantine on Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

In elderly people, Alzheimer's disease (AD) is the most common form of dementia. It has been shown that traditional Chinese medicine (TCM) based on phytomedicines enhances the therapeutic effects of modern medicine when taken in conjunction with them. Modern medicine N-methyl-D-aspartate receptor (NMDA) antagonist memantine (Mm) are mainly used in the clinical treatment of AD. TCM Cerebralcare Granule® (CG) has long been an effective treatment for headaches, dizziness, and other symptoms. In this study, we employ a blend of CG and Mm to address Alzheimer's disease-like symptoms and explore their impacts and underlying mechanisms.

AIM OF THE STUDY

The objective of our study was to observe the effects of CG combined with Memantine (Mm) on learning and memory impairment of AD mice induced by D-galactose and to explore the mechanism at work.

MATERIALS AND METHODS

CG and Mm were combined to target multiple pathological processes involved in AD. For a thorough analysis, we performed various experiments such as behavioral detection, pathological detection, proteomic detection, and other experimental methods of detection.

RESULTS

It was found that the combination of CG and Mm was significantly effective for improving learning and memory in AD mice as well as brain pathology. The serum and hippocampal tissue of AD mice were significantly enhanced with catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) levels were decreased with this treatment. In AD mice, a combination of Mm and CG (CG + Mm) significantly increased the levels of the anti-inflammatory factors IL-4 and IL-10, decreased the levels of pro-inflammatory factors (IL-6, IL-1β) and tumor necrosis factor-alpha (TNF-α), improved synaptic plasticity by restoring synaptophysin (SYP) and postsynaptic density protein-95 (PSD-95) expression in the hippocampus, enhanced Aβ phagocytosis of microglia in AD mice, and increased mitochondrial respiratory chain enzyme complexes I, II, III, and IV, lead to an increase in the number of functionally active NMDA receptors in the hippocampus. Proteomic analysis GO analysis showed that the positive regulation gene H3BIV5 of G protein coupled receptor signal pathway and synaptic transmission was up-regulated, while the transsynaptic signal of postsynaptic membrane potential and regulation-related gene Q5NCT9 were down-regulated. Most proteins showed significant enriched signal transduction pathway profiles after CG + Mm treatment, based on the KEGG pathway database.

CONCLUSION

The data supported the idea that CG and Mm could be more effective in treating AD mice induced by D-galactose than Mm alone. We provided a basis for the clinical use of CG with Mm.

Dynamics of myelin deficits in the 5xFAD mouse model for Alzheimer's disease and the protective role of BDNF

Recent findings highlight myelin breakdown as a decisive early event in Alzheimer's Disease (AD) acting as aggravating factor of its progression. However, it is still unclear whether myelin loss is attributed to increased oligodendrocyte vulnerability, reduced repairing capacity or toxic stimuli. In the present study, we sought to clarify the starting point of myelin disruption accompanied with Oligodendrocyte Progenitor Cell (OPC) elimination in the brain of the 5xFAD mouse model of AD at 6 months of age in Dentate Gyrus of the hippocampus in relation to neurotrophin system. Prominent inflammation presence was detected since the age of 6 months playing a key role in myelin disturbance and AD progression. Expression analysis of neurotrophin receptors in OPCs was performed to identify new targets that could increase myelination in health and disease. OPCs in both control and 5xFAD mice express TrkB, TrkC and p75 receptors but not TrkA. Brain-derived neurotrophic factor (BDNF) that binds to TrkB receptor is well-known about its pro-myelination effect, promoting oligodendrocytes proliferation and differentiation, so we focused our investigation on its effects in OPCs under neurodegenerative conditions. Our in vitro results showed that BDNF rescues OPCs from death and promotes their proliferation and differentiation in presence of the toxic Amyloid-β 1-42. Collectively, our results indicate that BDNF possess an additional neuroprotective role through its actions on oligodendrocytic component and its use could be proposed as a drug-based myelin-enhancing strategy, complementary to amyloid and tau centered therapies in AD.

Qingzhuan dark tea Theabrownin alleviates hippocampal injury in HFD-induced obese mice through the MARK4/NLRP3 pathway

Background

Feeding on a high-fat diet (HFD) results in obesity and chronic inflammation, which may have long-term effects on neuroinflammation and hippocampal injury. Theabrownin, a biologically active compound derived from the microbial fermentation of Qingzhuan dark tea, exhibits anti-inflammatory properties and lipid-lowering effects. Nevertheless, its potential in neuroprotection has yet to be investigated. Consequently, this study aims to investigate the neuroprotective effects of Theabrownin extracted from Qingzhuan dark tea, as well as its potential therapeutic mechanisms.

Methods

Male C57 mice were subjected to an 8-week HFD to induce obesity, followed by oral administration of Theabrownin from Qingzhuan dark tea. Lipid levels were detected by Elisa kit, hippocampal morphological damage was evaluated by HE and Nissl staining, and the expression levels of GFAP, IBA1, NLRP3, MARK4, and BAX in the hippocampus were detected by immunofluorescence (IF), and protein expression levels of NLRP3, MARK4, PSD95, SYN1, SYP, and Bcl-2 were detected by Western Blot (WB).

Results

Theabrownin treatment from Qingzhuan dark tea prevents alterations in body weight and lipid levels in HFD-fed mice. Furthermore, Theabrownin decreased hippocampal morphological damage and reduced the activation of astrocytes and microglia in HFD-fed mice. Moreover, Theabrownin decreased the expression of MARK4 and NLRP3 in HFD-fed mice. Besides, Theabrownin elevated the expression of PSD95, SYN1, and SYP in HFD-fed obese mice. Finally, Theabrownin prevented neuronal apoptosis, reduced the expression of BAX, and increased the expression of Bcl-2 in HFD-fed obese mice.

Conclusions

In summary, our current study presents the first demonstration of the effective protective effect of Theabrownin from Qingzhuan dark tea against HFD-induced hippocampal damage in obese mice. This protection may result from the regulation of the MARK4/NLRP3 signaling pathway, subsequently inhibiting neuroinflammation, synaptic plasticity, and neuronal apoptosis.

The Association among Hypothalamic Subnits, Gonadotropic and Sex Hormone Plasmas Levels in Alzheimer's Disease

This study investigates the sex-specific role of the Hypothalamic-Pituitary-Gonadal axis in Alzheimer's disease progression, utilizing ADNI1 data for 493 individuals, analyzing plasma levels of gonadotropic and sex hormones, and examining neurodegeneration-related brain structures. We assessed plasma levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P4), and testosterone (T), along with volumetric measures of the hippocampus, entorhinal cortex, and hypothalamic subunits, to explore their correlation with Alzheimer's disease markers across different cognitive statuses and sexes. Significant cognitive status effects were observed for all volumetric measures, with a distinct sex-by-cognitive status interaction for hypothalamic volume, indicating a decrease in males but not in females across cognitive impairment stages. Regression analyses showed specific hypothalamic subunit volume related to hormone levels, accounting for up to approximately 40% of the variance (p < 0.05). The findings highlight sex differences in neurodegeneration and hormonal regulation, suggesting potential for personalized treatments and advancing the understanding of Alzheimer's disease etiology.

Identification of novel hub genes for Alzheimer's disease associated with the hippocampus using WGCNA and differential gene analysis

Background

Alzheimer's disease (AD) is a common, refractory, progressive neurodegenerative disorder in which cognitive and memory deficits are highly correlated with abnormalities in hippocampal brain regions. There is still a lack of hippocampus-related markers for AD diagnosis and prevention.

Methods

Differently expressed genes were identified in the gene expression profile GSE293789 in the hippocampal brain region. Enrichment analyses GO, KEGG, and GSEA were used to identify biological pathways involved in the DEGs and AD-related group. WGCNA was used to identify the gene modules that are highly associated with AD in the samples. The intersecting genes of the genes in DEGs and modules were extracted and the top ten ranked hub genes were identified. Finally GES48350 was used as a validation cohort to predict the diagnostic efficacy of hub genes.

Results

From GSE293789, 225 DEGs were identified, which were mainly associated with calcium response, glutamatergic synapses, and calcium-dependent phospholipid-binding response. WGCNA analysis yielded dark green and bright yellow modular genes as the most relevant to AD. From these two modules, 176 genes were extracted, which were taken to be intersected with DEGs, yielding 51 intersecting genes. Then 10 hub genes were identified in them: HSPA1B, HSPB1, HSPA1A, DNAJB1, HSPB8, ANXA2, ANXA1, SOX9, YAP1, and AHNAK. Validation of these genes was found to have excellent diagnostic performance.

Conclusion

Ten AD-related hub genes in the hippocampus were identified, contributing to further understanding of AD development in the hippocampus and development of targets for therapeutic prevention.