Evaluating the Evidence for Neuroprotective and Axonal Regenerative Activities of Different Inflammatory Cell Types After Optic Nerve Injury

The optic nerve contains retinal ganglion cell (RGC) axons and functions to transmit visual stimuli to the brain. Injury to the optic nerve from ischemia, trauma, or disease leads to retrograde axonal degeneration and subsequent RGC dysfunction and death, causing irreversible vision loss. Inflammatory responses to neurological damage and axonal injuries in the central nervous system (CNS) are typically harmful to neurons and prevent recovery. However, recent evidence indicates that certain inflammatory cell types and signaling pathways are protective after optic nerve injury and promote RGC survival and axonal regeneration. The objective of this review is to examine the evidence for diverse effects of inflammatory cell types on the retina and optic nerve after injury. Additionally, we highlight promising avenues for further research.

QSP Modeling Shows Pathological Synergism Between Insulin Resistance and Amyloid-Beta Exposure in Upregulating VCAM1 Expression at the BBB Endothelium

Type 2 diabetes mellitus (T2DM), characterized by insulin resistance, is closely associated with Alzheimer's disease (AD). Cerebrovascular dysfunction is manifested in both T2DM and AD, and is often considered as a pathological link between the two diseases. Insulin signaling regulates critical functions of the blood-brain barrier (BBB), and endothelial insulin resistance could lead to BBB dysfunction, aggravating AD pathology. However, insulin signaling is intrinsically dynamic and involves interactions among numerous molecular mediators. Hence, a mechanistic systems biology model is needed to understand how insulin regulates BBB physiology and the consequences of its impairment in T2DM and AD. In this study, we investigated the pharmacodynamic effect of insulin on the expression of vascular cell adhesion molecule 1 (VCAM1), a marker of cerebrovascular inflammation. Intriguingly, normal insulin concentrations selectively activated the PI3K-AKT pathway, leading to decreased VCAM1 expression. However, exposure to supraphysiological insulin levels, which is present in insulin resistance, activated both PI3K-AKT and MEK-ERK pathways, and increased VCAM1 expression. We developed a mathematical model that adequately described the dynamics of various insulin signaling nodes and VCAM1 expression. Further, the model was integrated with in vitro proteomics and transcriptomics data from AD patients to simulate VCAM1 expression under pathological conditions. This approach allowed us to establish a quantitative systems pharmacology framework to investigate BBB dysfunction in AD and metabolic syndrome, thereby offering opportunities to identify specific disruptions in molecular networks that will enable us to identify novel therapeutic targets.

An experimental framework for conjoint measures of olfaction, navigation, and motion as pre-clinical biomarkers of Alzheimer's disease

Elucidating Alzheimer's disease (AD) prodromal symptoms can resolve the outstanding challenge of early diagnosis. Based on intrinsically related substrates of olfaction and spatial navigation, we propose a novel experimental framework for their conjoint study. Artificial intelligence-driven multimodal study combining self-collected olfactory and motion data with available big clinical datasets can potentially promote high-precision early clinical screenings to facilitate timely interventions targeting neurodegenerative progression.

Catalpol promotes hippocampal neurogenesis and synaptogenesis in rats after multiple cerebral infarctions by mitochondrial regulation: involvement of the Shh signaling pathway

Introduction

Ischemic stroke greatly threatens human life and health. Neuro-restoration is considered to be the critical points in reestablishing neurological function and improving the quality of life of patients. Catalpol is the main active ingredient of the Chinese herbal medicine Dihuang, which has the beneficial efficacy in traditional remedy, is closely related to the mitochondrial morphology and function. In the present study, we investigated whether catalpol has a neurorestorative effect after multiple cerebral infarctions and its underlying mechanisms.

Methods

In this study, male 8-week-old Sprague-Dawley (SD) rats were grouped according to neurological deficit scores to minimize differences between groups the second day: sham group, model group, Ginkgo biloba P.E (EGb) (Ginaton:18 mg/kg) group, model + CAT 30 mg/kg group (CAT 30), model + CAT 60 mg/kg group (CAT 60), and model + CAT 120 mg/kg group (CAT 120). From the first day to the fourteenth day after MCI, rats were given the corresponding doses of drugs by gastric administration every day(1 mL/100g), and from day 7 to day 14, all rats were injected with Brdu solution (50 mg/kg) i.p. Neuro-Function was assessed by the neurologic deficit scores. Then we observed measurement of brain atrophy and fluorescent Nissl staining. The expression of BrdU+/DCX+ cells and the BDNF concentrations were tested to observe the neuro-restoration effect. Transmission electron microscope (TEM) and Western blot (WB) were used to observed synaptogenesis. we observed the restoration of mitochondrial function by detecting the intracortical calcium and T-AOC content. Finally, we examined the protein and mRNA expression of shh signaling pathway through q-PCR and WB.

Results

Catalpol alleviated neurological deficits, reduced the degree of brain atrophy, as well as minimize pathological damage in the hippocampus and cortex. In addition, catalpol also promoted hippocampal neurogenesis and synaptogenesis by improving the mitochondrial structure and promoting mitochondrial function, as evidenced by the up-regulation of positive expression of both Recombinant Doublecortin (DCX) and 5-Bromodeoxyuridinc (BrdU), the enhancement of the Total antioxidant capacity (T-AOC), and the increase in the expression of synapse-associated proteins, Synaptophysin (SYP) and post-synaptic density-95 (PSD-95). Finally, we observed that catalpol up-regulated the expression of Sonic hedgehog (Shh) and Glioma-associated homologue-1 (GLI-1), factors related to the Shh signaling pathway.

Discussion

In conclusion, catalpol may regulate mitochondria through activation of the Shh signaling pathway and exert its role in promoting hippocampal neurogenesis and synaptogenesis.

Aged mice show a reduction in 5-HT neurons and decreased cellular activation in the dentate gyrus when exposed to acute running

Serotonin (5-HT) is an important neurotransmitter for cognition and neurogenesis in the dentate gyrus (DG), which occurs via movement stimulation such as physical activity. Brain 5-HT function changes secondary to aging require further investigation. We evaluated whether aged animals would present changes in the number of 5-HT neurons in regions such as the dorsal (DRN) and median (MRN) raphe nuclei and possible changes in the rate of cellular activation in the DG in response to acute running, as a reduction in 5-HT neurons could contribute to a decline in neuronal activation in the DG in response to physical activity in aged mice. This study was conducted on adult (3 months old) and aged (19 months old) male and female mice. Immunohistochemistry, microscopic analysis, and treadmill-running tests were also performed. The data revealed that in aged mice, a reduction in the number of 5-HT neurons in the DRN and MRN of male and female mice was observed. The reduction in the DRN was greater in females. Furthermore, aged animals demonstrate a lower rate of c-Fos labeling in the DG when stimulated by physical exercise. These data indicate that aging may be associated with a reduction in the number of 5-HT neurons in the DRN and MRN, which may lead to a decline in 5-HT availability in the target regions, including the DG. The reduced c-Fos expression in the DG after running in aged mice indicates a decreased response to physical activity, which is potentially linked to serotonergic deficits.

Dietary interventions in mitigating the impact of environmental pollutants on Alzheimer's disease - A review

Numerous studies linking environmental pollutants to oxidative stress, inflammation, and neurotoxicity have assigned pollutants to several neurodegenerative disorders, including Alzheimer's disease (AD). Heavy metals, pesticides, air pollutants, and endocrine disruptor chemicals have been shown to play important roles in AD development, with some traditional functions in amyloid-β formation, tau kinase action, and neuronal degeneration. However, pharmacological management and supplementation have resulted in limited improvement. This raises the interesting possibility that activities usually considered preventive, including diet, exercise, or mental activity, might be more similar to treatment or therapy for AD. This review focuses on the effects of diet on the effects of environmental pollutants on AD. One of the primary issues addressed in this review is a group of specific diets, including the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH intervention for Neurodegenerative Delay (MIND), which prevent exposure to these toxins. Such diets have been proven to decrease oxidative stress and inflammation, which are unfavorable for neuronal growth. Furthermore, they contribute to positive changes in the composition of the human gut microbiota and thus encourage interactions in the Gut-Brain Axis, reducing inflammation caused by pollutants. This review emphasizes a multi-professional approach with reference to nutritional activities that would lower the neurotoxic load in populations with a high level of exposure to pollutants. Future studies focusing on diet and environment association plans may help identify preventive measures aimed at enhancing current disease deceleration.

Particulate matter exposure and its consequences on hippocampal neurogenesis and cognitive function in experimental models

Exposure to air pollution is thought to cause millions of deaths globally each year. According to the Who 2018, approximately 7 million deaths annually are caused predominantly by noncommunicable diseases due to air pollution. Exposure to air particulate matter 2.5 (PM2.5) has been strongly associated with increased mortality and has significant effects on brain health. Air pollution, particularly ultrafine particulate matter, has emerged as a serious environmental concern with profound implications for human health. Studies in animal models have indicated that exposure to these pollutants during gestational development impacts prenatal and postnatal brain development. In particular, air pollution has been increasingly identified as a potential causative factor, as it affects neurogenesis in the brain's hippocampal region. The hippocampus is highly vulnerable to PM exposure, and any alteration in the structure or function of this region leads to various neurodevelopmental defects and neurodegenerative disorders via oxidative stress, microglial activation, neuronal death, and differential expression of genes. The neurogenesis process involves several steps, such as proliferation, differentiation, migration, synaptogenesis, and neuritogenesis. If any step of the neurogenesis process is hampered by environmental exposure or other factors, it can lead to neurodevelopmental defects, neurodegenerative disorders, and cognitive decline. One significant contributor to these alterations is air pollution, which ranks as the leading environmental risk factor worldwide. Some of the most common effects include oxidative stress, neuroinflammation, depressive behavior, altered cognitive processes, and microglial activation. This review explores how prenatal and postnatal PM exposure affects the hippocampal regions of the brain and the defects associated with exposure.

Linking gut microbiota dysbiosis to molecular pathways in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline and synaptic dysfunction. Emerging evidence suggests a significant relationship between gut microbiota and brain health, mediated through the gut-brain axis. Alterations in gut microbiota composition may influence AD progression by affecting molecular pathways and miRNA interactions.

METHODS

We retrieved and analyzed microarray data from 34 tissue samples of AD patients and controls (GEO accession number GSE110298). Differentially expressed genes (DEGs) with the GCS score package in R, considering a p-value < 0.05 and logFC<-1 and logFC>1 to isolate significant gene clusters. Enrichment analysis of signaling pathways and gene ontology was conducted using Enrichr, KEGG, Panther, DAVID, and shiny GO databases. Protein-protein interactions were visualized with Networkanalyst and CytoScape. Gut microbiota in 200 CE patients was analyzed using next-generation sequencing (NGS) data from gutMDisorder and GMrepo databases. miRNA interactions were evaluated using miEAA, Targetscan, MienTurnet, and miRnet databases.

RESULTS

Significant reductions in microbial taxa, including Clostridia (LDA score -4.878208), Firmicutes (LDA score -4.817032), and Faecalibacterium (LDA score -4.40714), were observed in AD patients. Pathway analysis highlighted the involvement of Axon guidance, ErbB, and MAPK signaling pathways in AD. Venn diagram analysis identified 619 intersecting genes in brain and gut tissues, emphasizing pathways such as Axon Guidance and Cell Cycle. miRNA analysis revealed important regulatory miRNAs, including hsa-let-7c, hsa-mir-125b-2, and hsa-mir-145, which target key transcription factors involved in AD pathology.

CONCLUSION

The study demonstrates significant dysbiosis in the gut microbiota of AD patients and underscores the potential role of gut microbiota in AD progression through altered signaling pathways and miRNA interactions. These findings highlight the need for further research into microbiota-based interventions as potential therapeutic strategies for AD.

Subcellular Localization Guides eNOS Function

Nitric oxide synthases (NOS) are enzymes responsible for the cellular production of nitric oxide (NO), a highly reactive signaling molecule involved in important physiological and pathological processes. Given its remarkable capacity to diffuse across membranes, NO cannot be stored inside cells and thus requires multiple controlling mechanisms to regulate its biological functions. In particular, the regulation of endothelial nitric oxide synthase (eNOS) activity has been shown to be crucial in vascular homeostasis, primarily affecting cardiovascular disease and other pathophysiological processes of importance for human health. Among other factors, the subcellular localization of eNOS plays an important role in regulating its enzymatic activity and the bioavailability of NO. The aim of this review is to summarize pioneering studies and more recent publications, unveiling some of the factors that influence the subcellular compartmentalization of eNOS and discussing their functional implications in health and disease.

Polypharmacological Drug Design Guided by Integrating Phenotypic and Restricted Fragment Docking Strategies

Polypharmacological drugs are of great value for treating complex human diseases by the combinative modulation of several biological targets. However, multitarget drug design with more than two targets is challenging and generally discovered by serendipity. Herein, a restricted fragment docking (RFD) computational method combined with a phenotypic discovery approach was developed for rational polypharmacological drug design. Via genetic and drug combination studies in a microglial phenotype, we first identified novel synergistic effects by triple target modulation toward RIPK1, MAP4K4, and ALK. Drawing on the RFD method to explore virtual chemical spaces in three target pockets, we identified a lead compound, LP-10d, that precisely modulated RIPK1/MAP4K4/ALK for synergistic microglial protection with low nanomolar potency. LP-10d showed polypharmacology against multiple neuropathologies in the 3xTg Alzheimer's disease mouse model. Our study revealed a potential application of the RFD method, which is valuable to further polypharmacological drug discovery involved in clinical studies for treating complex human diseases.

Association of Cerebrovascular Reactivity With 1-Year Imaging and Clinical Outcomes in Small Vessel Disease: An Observational Cohort Study

BACKGROUND AND OBJECTIVES

In patients with cerebral small vessel disease (SVD), impaired cerebrovascular reactivity (CVR) is related to worse concurrent SVD burden, but less is known about cerebrovascular reactivity and long-term SVD lesion progression and clinical outcomes. We investigated associations between cerebrovascular reactivity and 1-year progression of SVD features and clinical outcomes.

METHODS

Between 2018 and 2021, we recruited patients from the Edinburgh/Lothian stroke services presenting with minor ischemic stroke and SVD features as part of the Mild Stroke Study 3, a prospective observational cohort study (ISRCTN 12113543). We acquired 3T brain MRI at baseline and 1 year. At baseline, we measured cerebrovascular reactivity to 6% inhaled CO2 in subcortical gray matter, normal-appearing white matter, and white matter hyperintensities (WMH). At baseline and 1 year, we quantified SVD MRI features, incident infarcts, assessed stroke severity (NIH Stroke Scale), recurrent stroke, functional outcome (modified Rankin Scale), and cognition (Montreal Cognitive Assessment). We performed linear and logistic regressions adjusted for age, sex, and vascular risk factors, reporting the regression coefficients and odds ratios with 95% CIs.

RESULTS

We recruited 208 patients of whom 163 (mean age and SD: 65.8 ± 11.2 years, 32% female) had adequate baseline CVR and completed the follow-up structural MRI. The median increase in WMH volume was 0.32 mL with (Q1, Q3) = (-0.48, 1.78) mL; 29% had a recurrent stroke or incident infarct on MRI. At 1 year, patients with lower baseline cerebrovascular reactivity in normal-appearing tissues had increased WMH (regression coefficient: B = -1.14 [-2.13, -0.14] log10 (%ICV) per %/mm Hg) and perivascular space volumes (B = -1.90 [-3.21, -0.60] log10 (%ROIV) per %/mm Hg), with a similar trend in WMH. CVR was not associated with clinical outcomes at 1 year.

DISCUSSION

Lower baseline cerebrovascular reactivity predicted an increase in WMH and perivascular space volumes after 1 year. CVR should be considered in SVD future research and intervention studies.

Rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone prevent amnesia induced in scopolamine zebrafish (Danio rerio) model by increasing the mRNA expression of bdnf, npy, egr-1, nfr2α, and creb1 genes

The increasing attention towards age-related diseases has generated significant interest in the concept of cognitive dysfunction associated with Alzheimer's disease (AD). Certain limitations are associated with the current therapies, and flavonoids have been reported to exhibit multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this study, we performed an initial in silico predictions of the pharmacokinetic properties of three flavonoids (rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone). Subsequently, we evaluated the antiamnesic and antioxidant potential of flavonoids in concentrations of 1, 3, and 5 μg/L in scopolamine (100 μM)-induced amnesic zebrafish (Danio rerio) model. Zebrafish behavior was analyzed by novel tank diving test (NTT), Y-maze, and novel object recognition test (NOR). Acetylcholinesterase (AChE) activity, brain antioxidant status and the expression of bdnf, npy, egr1, nrf2α, creb1 genes, and CREB-1 protein level was measured to elucidate the underlying mechanism of action. Our flavonoids improved memory and decreased anxiety-like behavior of scopolamine-induced amnesia in zebrafish. Also, the studied flavonoids reduced AChE activity and brain oxidative stress and upregulated the gene expression, collectively contributing to neuroprotective properties. The results of our study add new perspectives on the properties of flavonoids to regulate the evolution of neurodegenerative diseases, especially AD, by modulating the expression of genes involved in the regulation of synaptic plasticity, axonal growth, and guidance, sympathetic and vagal transmission, the antioxidant response and cell proliferation and growth.

Cholinesterase Inhibitor Reveals Synergistic Potential for Neural Stem Cell-Based Therapy in the 5xFAD Mouse Model of Alzheimer's Disease

Background and Objectives

Stem cell therapy shows great promise for treating Alzheimer's disease (AD). Cholinesterase inhibitors (ChEIs) like donepezil are well-established for alleviating AD symptoms. This study aimed to determine if combining ChEI treatment with stem cell therapy could improve therapeutic outcomes.

Methods

Neural stem cells (NSCs) were injected into the hippocampus of the 5xFAD AD mice using a stereotactic technique. Following this, donepezil or a placebo was administered for one month. We assessed behavioral improvements, survival and health of the grafts, and changes in synaptic density.

Results

The AD mice demonstrated cognitive impairment in both the Morris water maze and novel object recognition tests. In groups receiving stem cell therapy, donepezil enhanced the survival and neuronal differentiation of grafted NSCs, promoting the establishment of synaptic connections with the host brain. The combined treatment with donepezil and NSC transplantation more effectively increased synaptic density and improved behavioral performance in AD mice compared to NSC transplantation alone.

Conclusion

Combining ChEIs with NSC transplantation produces synergistic effects in AD treatment. This approach highlights the potential of integrating these therapies to develop more effective strategies for managing Alzheimer's disease.

Early disruption of the CREB pathway drives dendritic morphological alterations in FTD/ALS cortical neurons

Synaptic loss and dendritic degeneration are common pathologies in several neurodegenerative diseases characterized by progressive cognitive and/or motor decline, such as Alzheimer's disease (AD) and frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS). An essential regulator of neuronal health, the cAMP-dependent transcription factor CREB positively regulates synaptic growth, learning, and memory. Phosphorylation of CREB by protein kinase A (PKA) and other cellular kinases promotes neuronal survival and maturation via transcriptional activation of a wide range of downstream target genes. CREB pathway dysfunction has been strongly implicated in AD pathogenesis, and recent data suggest that impaired CREB activation may contribute to disease phenotypes in FTD/ALS as well. However, the mechanisms behind reduced CREB activity in FTD/ALS pathology are not clear. In this study, we found that cortical-like neurons derived from iPSC lines carrying the hexanucleotide repeat expansion in the C9ORF72 gene, a common genetic cause of FTD/ALS, displayed a diminished activation of CREB, resulting in decreased dendritic and synaptic health. Importantly, we determined such impairments to be mechanistically linked to an imbalance in the ratio of regulatory and catalytic subunits of the CREB activator PKA and to be conserved in C9-ALS patient's postmortem tissue. Modulation of cAMP upstream of this impairment allowed for a rescue of CREB activity and an amelioration of dendritic morphology and synaptic protein levels. Our data elucidate the mechanism behind early CREB pathway dysfunction and discern a feasible therapeutic target for the treatment of FTD/ALS and possibly other neurodegenerative diseases.

APOE 𝜀4-related blood-brain barrier breakdown is associated with microstructural abnormalities

INTRODUCTION

Blood-brain barrier (BBB) dysfunction occurs in Alzheimer's disease (AD). Yet, the stage at which it appears along the AD time course and whether it contributes to neurodegeneration remain unclear.

METHODS

Older adults (61 to 90 years) from cognitively normal (CN) to mildly cognitively impaired (CI), enriched for APOE 𝜀4 and amyloid positivity, underwent dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and diffusion MRI to measure BBB permeability and brain microstructure. Analysis of variance compared BBB permeability according to cognitive status, amyloid beta (Aβ), and APOE4. Linear regressions assessed associations of BBB permeability with brain microstructure and interactions with Aβ and APOE4.

RESULTS

BBB permeability was elevated for APOE4 carriers across the cortical gray matter, with the strongest differences among CN amyloid-negative individuals. Associations between entorhinal BBB permeability and microstructure interacted with Aβ and APOE4, with the strongest relationships in amyloid-positive individuals and APOE4 carriers.

DISCUSSION

APOE4 may drive widespread BBB dysfunction in preclinical AD, which may contribute to neurodegenerative changes early along the AD cascade.

HIGHLIGHTS

Gray matter blood-brain barrier (BBB) permeability is elevated for APOE4 carriers. APOE4-related BBB breakdown appears in the absence of cognitive decline or amyloid. BBB leakage correlates with entorhinal cortex microstructural injury. Associations with microstructure are strongest for amyloid-positive APOE4 carriers.

Cardioprotective effects of polydatin against myocardial injury in HFD/stz and high glucose-induced diabetes via a Caveolin 1-dependent mechanism

BACKGROUND

Diabetic cardiomyopathy (DCM) is defined as cardiac dysfunction involving changes in structure, function, and metabolism in the absence of coronary artery disease, which eventually developed into heart failure. There is still a lack of effective drugs for the treatment of DCM, while the ameliorative effects of traditional herbs on DCM have been commonly reported. Polydatin (PD) is a glucoside derivative of traditional herbs of resveratrol, which has been shown to ameliorate the pathological development of DCM. However, the cardioprotective effect and mechanism of PD in the improvement of myocardial injury are still unclear.

AIM OF STUDY

This study aimed to investigate the cardio-protective role of PD on DCM and reveal the critical effect of Cav1 in PD' regulation of DCM.

MATERIALS AND METHODS

The Cav1-/- and Cav1+/+mice and H9C2 cells were used to induce DCM models and then given PD treatment (150 mg/kg) or not. The cardiac functions of all mice were checked via echocardiography, and myocardial histological changes were measured by H&E, periodic acid-schiff (PAS) and Masson staining. The markers expression of heart fibrosis and inflammation, and hypertrophic factors were detected using western blotting. The NF-κB signaling activation was performed by confocal, immunohistochemical, Electrophoretic mobility shift assay (EMSA) and western blotting.

RESULTS

Here, we found that PD significantly improved the cardiac function and injury of diabetic Cav1+/+ mice, and enhanced the expression of Cav1 in the cardiac tissues of diabetic Cav1+/+ mice and HG-induced H9C2 cells. Further investigation showed that when Cav1 was knocked down, PD no longer plays the cardioprotective effect and inhibits the NF-κB signaling pathway activation in HFD/stz-treated diabetic mice and HG-induced H9C2 cells.

CONCLUSION

These results demonstrated that PD inhibited the hyperglycemia-induced myocardial injury and inflammatory fibrosis of DCM models in vivo and in vitro, and targeting Cav1 may provide a novel understanding the mechanism of the treatment of PD in DCM.

The BDNF-Interactive Model for Sustainable Hippocampal Neurogenesis in Humans: Synergistic Effects of Environmentally-Mediated Physical Activity, Cognitive Stimulation, and Mindfulness

This paper bridges critical gaps through proposing a novel, environmentally mediated brain-derived neurotrophic factor (BDNF)-interactive model that promises to sustain adult hippocampal neurogenesis in humans. It explains how three environmental enrichment mechanisms (physical activity, cognitive stimulation, and mindfulness) can integratively regulate BDNF and other growth factors and neurotransmitters to support neurogenesis at various stages, and how those mechanisms can be promoted by the physical environment. The approach enables the isolation of specific environmental factors and their molecular effects to promote sustainable BDNF regulation by testing the environment's ability to increase BDNF immediately or shortly before it is consumed for muscle repair or brain update. This model offers a novel, feasible method to research environment enrichment and neurogenesis dynamics in real-world human contexts at the immediate molecular level, overcoming the confounds of complex environment settings and challenges of long-term exposure and structural plasticity changes. The model promises to advance understanding of environmental influences on the hippocampus to enhance brain health and cognition. This work bridges fundamental gaps in methodology and knowledge to facilitate more research on the enrichment-neuroplasticity interplay for humans without methodological limitations.

Photoacoustic and fluorescence dual-modality imaging of cerebral biomarkers in Alzheimer's disease rodent model

Significance

Alzheimer's disease (AD) is a predominant form of dementia that can lead to a decline in the quality of life and mortality. The understanding of the pathological changes requires monitoring of multiple cerebral biomarkers simultaneously with high resolution. Photoacoustic microscopy resolves single capillaries, allowing investigations into the most affected types of vessels. Combined with confocal fluorescence microscopy, the relationship between plaque deposition and small vessel pathology could be better understood.

Aim

We aim to introduce a dual-modality imaging system combining photoacoustic microscopy (PAM) and confocal fluorescence microscopy (CFM) to provide a comprehensive view of both cerebral cortical vessels and amyloid- β ( A β ) plaque in AD mouse model in vivo and to identify the pathological changes of these two biomarkers.

Approach

We developed a dual-modality imaging system to image both cerebral vessel structure and A β plaque on groups of mice with different ages and phenotypes. Vessel imaging is enabled by PAM, whereas A β plaque is imaged by CFM with the aid of fluorescent dye.

Results

The small vessel density in the AD group was significantly lower than in the control group, whereas the A β plaque density in the AD group was not only higher but also increased with age.

Conclusions

This dual-modality system provides a powerful platform for biomarker monitoring of AD expressing multi-dimensional pathological changes.

A critical appraisal on the involvement of plant-based extracts as neuroprotective agents (2012-2022): an effort to ease out decision-making process for researchers

The purpose of this review study is to provide a condensed compilation of 164 medicinal plants that have been investigated for their neuroprotective aspects by researchers between the years 2012 and 2022 which also includes a recent update of 2023-2024. After using certain keywords to retrieve the data from SCOPUS, it was manually sorted to eliminate any instances of duplication. The article is streamlined into three major segments. The first segment takes a dig into the current global trend and attempts to decrypt vital information related to plant names, families, plant parts used, and neurological disorders investigated. The second segment of the article makes an attempt to present a comprehensive insight into the various mechanistic pathways through which phytochemicals can intervene to exert neuroprotection. The final segment of the manuscript is a bibliometric appraisal of all researches conducted. The study is based on 256 handpicked articles based on decided inclusion criteria. Illustrative compilation of various pathways citing their activation and deactivation channels are also presented with possible hitting points of various phytochemicals. The present study employed Microsoft Excel 2019 and VOS viewer as data visualisation tools.

Pleiotrophin modulates acute and long-term LPS-induced neuroinflammatory responses and hippocampal neurogenesis

The hippocampus is one of the most vulnerable regions affected in disorders characterized by overt neuroinflammation such as neurodegenerative diseases. Pleiotrophin (PTN) is a neurotrophic factor that modulates acute neuroinflammation in different contexts. PTN is found highly upregulated in the brain in different chronic disorders characterized by neuroinflammation, suggesting an important role in the modulation of sustained neuroinflammation. To test this hypothesis, we studied the acute and long-term effects of a single lipopolysaccharide (LPS; 5 mg/kg) administration in Ptn+/+ and Ptn-/- mice, and in mice with Ptn-overexpression (Ptn-Tg). Endogenous PTN levels proportionally modulate LPS-induced increase in TNF-α plasma levels one hour after treatment. In the dentate gyrus (DG) of the hippocampus, a lower percentage of DCX+ cells were detected in saline-treated Ptn-/- mice compared to Ptn+/+ mice, suggesting a crucial role of PTN in the maintenance of hippocampal neuronal progenitors. The data show that PTN overexpression tends to potentiate acute microglial responses in the DG 16 hours after LPS treatment. Remarkably, a significant increase in the number of neuronal progenitors together with astrogliosis was detected 10 months after a single injection of LPS treatment in wild type mice. However, these LPS-induced long-term effects were prevented in Ptn-/- and Ptn-Tg mice, suggesting that PTN modulates LPS-induced long-term neurogenesis changes and astrocytic response in the hippocampus. The data presented here suggest that endogenous PTN levels are crucial in the regulation of acute LPS-induced systemic and hippocampal microglial responses in young mice. Furthermore, our findings provide evidence of the key role of PTN in the regulation of long-term LPS effects on astrocytic response and neurogenesis in the hippocampus.

The impact of aging on HIV-1-related neurocognitive impairment

Depending on the population studied, HIV-1-related neurocognitive impairment is estimated to impact up to half the population of people living with HIV (PLWH) despite the availability of combination antiretroviral therapy (cART). Various factors contribute to this neurocognitive impairment, which complicates our understanding of the molecular mechanisms involved. Biological aging has been implicated as one factor possibly impacting the development and progression of HIV-1-related neurocognitive impairment. This is increasingly important as the life expectancy of PLWH with virologic suppression on cART is currently projected to be similar to that of individuals not living with HIV. Based on our increasing understanding of the biological aging process on a cellular level, we aim to dissect possible interactions of aging- and HIV-1 infection-induced effects and their role in neurocognitive decline. Thus, we begin by providing a brief overview of the clinical aspects of HIV-1-related neurocognitive impairment and review the accumulating evidence implicating aging in its development (Part I). We then discuss potential interactions between aging-associated pathways and HIV-1-induced effects at the molecular level (Part II).

Differential impact of eicosapentaenoic acid and docosahexaenoic acid in an animal model of Alzheimer's disease

Dietary supplementation with n-3 polyunsaturated fatty acids improves cognitive performance in several animal models of Alzheimer's disease (AD), an effect often associated with reduced amyloid-beta and/or tau pathologies. However, it remains unclear to what extent eicosapentaenoic (EPA) provides additional benefits compared to docosahexaenoic acid (DHA). Here, male and female 3xTg-AD mice were fed for 3 months (13-16 months of age) the following diets: (1) control (no DHA/EPA), (2) DHA (1.1g/kg) and low EPA (0.4g/kg), or (3) DHA (0.9g/kg) with high EPA (9.2g/kg). The DHA and DHA + EPA diets respectively increased DHA by 19% and 8% in the frontal cortex of 3xTg-AD mice, compared to controls. Levels of EPA, which were below the detection limit after the control diet, reached 0.14% and 0.29% of total brain fatty acids after the DHA and DHA + EPA diet, respectively. DHA and DHA + EPA diets lowered brain arachidonic acid levels and the n-6:n-3 docosapentaenoic acid ratio. Brain uptake of free 14C-DHA measured through intracarotid brain perfusion, but not of 14C-EPA, was lower in 3xTg-AD than in NonTg mice. DHA and DHA + EPA diets in 3xTg-AD mice reduced cortical soluble phosphorylated tau (pS202) (-34% high-DHA, -34% DHA + EPA, P < 0.05) while increasing p21-activated kinase (+58% and +83%, P < 0.001; respectively). High EPA intake lowered insoluble phosphorylated tau (-31% vs. DHA, P < 0.05). No diet effect on amyloid-beta levels was observed. In conclusion, dietary intake of DHA and EPA leads to differential changes in brain PUFA while altering cerebral biomarkers consistent with beneficial effects against AD-like neuropathology.

The relative brain signal variability increases in the behavioral variant of frontotemporal dementia and Alzheimer's disease but not in schizophrenia

Overlapping symptoms between Alzheimer's disease (AD), behavioral variant of frontotemporal dementia (bvFTD), and schizophrenia (SZ) can lead to misdiagnosis and delays in appropriate treatment, especially in cases of early-onset dementia. To determine the potential of brain signal variability as a diagnostic tool, we assessed the coefficient of variation of the BOLD signal (CVBOLD) in 234 participants spanning bvFTD (n = 53), AD (n = 17), SZ (n = 23), and controls (n = 141). All underwent functional and structural MRI scans. Data unveiled a notable increase in CVBOLD in bvFTD patients across both datasets (local and international, p < 0.05), revealing an association with clinical scores (CDR and MMSE, r = 0.46 and r = -0.48, p < 0.0001). While SZ and control group demonstrated no significant differences, a comparative analysis between AD and bvFTD patients spotlighted elevated CVBOLD in the frontopolar cortices for the latter (p < 0.05). Furthermore, CVBOLD not only presented excellent diagnostic accuracy for bvFTD (AUC 0.78-0.95) but also showcased longitudinal repeatability. During a one-year follow-up, the CVBOLD levels increased by an average of 35% in the bvFTD group, compared to a 2% increase in the control group (p < 0.05). Our findings suggest that CVBOLD holds promise as a biomarker for bvFTD, offering potential for monitoring disease progression and differentiating bvFTD from AD and SZ.

Taohe Chengqi decoction improves diabetic cognitive dysfunction by alleviating neural stem cell senescence through HIF1α-driven metabolic signaling

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is characterized by numerous long-term complications, in which progressive cognitive decline represents a significant risk factor for dementia and other neurodegenerative disorders. Taohe Chengqi decoction (THCQ) is a common traditional Chinese formula for treating T2DM; however, the neuroprotective effect of THCQ on diabetes-associated cognitive dysfunction remains unclear. Hence, the present study investigated the therapeutic effects of THCQ on cognitive impairment associated with T2DM and elucidated the underlying mechanisms.

METHODS

A stable high-fat diet (HFD) and streptozotocin (STZ)-induced T2DM mouse model was established and received intragastrical THCQ administration. Blood and tissue samples were investigated for biochemical parameters and neuropathology, whereas hippocampal tissue underwent transcriptome analyses and the role of neural stem cell (NSC) senescence was detected both in vivo and in vitro. Network pharmacology analysis and subsequent primary NSC experiments were conducted to explore the involvement of the HIF1α signaling pathway in THCQ-mediated hippocampal NSC senescence. Furthermore, a lentivirus vector overexpressing HIF1α was used to verify the THCQ potential therapeutic effects on HIF1α/PDKs metabolic signaling that influenced NSC senescence.

RESULTS

THCQ alleviated cognitive dysfunction and metabolic abnormalities in HFD/STZ mice, and relieved hippocampal neurodegeneration. Transcriptome analyses and validation experiments revealed THCQ-induced neuroprotective effects by targeting high glucose-mediated hippocampal neuropathy and NSC senescence. Bioinformatic analysis indicated that HIF1α signaling played a significant role in THCQ therapeutic outcomes; while HIF1α overexpression impaired the effects of THCQ on high glucose-induced metabolic disorders and NSC senescence.

CONCLUSION

The present study demonstrated that THCQ improved diabetic cognitive dysfunction and hippocampal neurogenesis, the effects of which were mainly attributed to the restoration of metabolic homeostasis and inhibition of NSC senescence through HIF1α signaling. Our results provide novel insights into the therapeutic framework for diabetic neuropathy and indicate that THCQ might be a promising candidate for the management of T2DM-related cognitive disorders.

Vulnerability of neurofilament-expressing neurons in frontotemporal dementia

Frontotemporal dementia (FTD) is an umbrella term for several early onset dementias, that are caused by frontotemporal lobar degeneration (FTLD), which involves the atrophy of the frontal and temporal lobes of the brain. Neuron loss in the frontal and temporal lobes is a characteristic feature of FTLD, however the selective vulnerability of different neuronal populations in this group of diseases is not fully understood. Neurofilament-expressing neurons have been shown to be selectively vulnerable in other neurodegenerative diseases, including Alzheimer's disease and amyotrophic lateral sclerosis, therefore we sought to investigate whether this neuronal population is vulnerable in FTLD. We also examined whether neuronal sub-type vulnerability differed between FTLD with TDP-43 inclusions (FTLD-TDP) and FTLD with tau inclusions (FTLD-Tau). Post-mortem human tissue from the superior frontal gyrus (SFG) of FTLD-TDP (n = 15), FTLD-Tau (n = 8) and aged Control cases (n = 6) was immunolabelled using antibodies against non-phosphorylated neurofilaments (SMI32 antibody), calretinin and NeuN, to explore neuronal cell loss. The presence of non-phosphorylated neurofilament immunolabelling in axons of the SFG white matter was also quantified as a measure of axon pathology, as axonal neurofilaments are normally phosphorylated. We demonstrate the selective loss of neurofilament-expressing neurons in both FTLD-TDP and FTLD-Tau cases compared to aged Controls. We also show that non-phosphorylated neurofilament axonal pathology in the SFG white matter was associated with increasing age, but not FTLD. This data suggests neurofilament-expressing neurons are vulnerable in both FTLD-TDP and FTLD-Tau.

A Comprehensive Stereology Method for Quantitative Evaluation of Neuronal Injury, Neurodegeneration, and Neurogenesis in Brain Disorders

Neuronal injury, neurodegeneration, and neuroanatomical changes are key pathological features of various neurological disorders, including epilepsy, stroke, traumatic brain injury, Parkinson's disease, autism, and Alzheimer's disease. Accurate quantification of neurons and interneurons in different brain regions is critical for understanding the progression of neurodegenerative disorders in animal models. Traditional scoring methods are often superficial, biased, and unreliable for evaluating neuropathology. Stereology, a quantitative tool that uses 3-dimensional visualization of cells, provides a robust protocol for evaluating neuronal injury and neurodegeneration. This article presents a comprehensive and optimized stereology protocol for unbiased quantification of neuronal injury, neurodegeneration, and neurogenesis in rat and mouse models. This protocol involves precise counting of injured neurons, surviving neurons, and interneurons through immunohistochemical processing of brain sections for NeuN(+) principal neurons, parvalbumin (PV+) interneurons, doublecortin (DCX+) newborn neurons, and Fluoro-Jade B (FJB+)-stained injured cells. Predefined hippocampal and amygdala regions were identified and analyzed using a Visiopharm stereology software-driven compound microscope. Cell density and absolute cell numbers were determined using the optical fractionation method. Our stereology protocol accurately estimated 1.5 million total NeuN(+) principal neurons and 0.05 million PV(+) interneurons in the rat hippocampus, as well as 1.2 million total principal neurons and 0.025 million interneurons in the mouse hippocampus. FJB(+) counting provided a quantitative index of damaged neurons, and the stereology of DCX(+) neurons demonstrated the extent of neurogenesis. Overall, this stereology protocol enables precise, accurate, and unbiased counting of total neurons in any brain region. This offers a reliable quantitative tool for studying neuronal injury and protection in various models of acute brain injury, neurotoxicity, and chronic neurological disorders. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Stereological quantification of principal neurons, interneurons, and immature neurons in the hippocampus in rat brain sections Basic Protocol 2: Stereological quantification of principal neurons, interneurons, and immature neurons in the hippocampus in mouse brain sections Basic Protocol 3: Stereological quantification of injured or necrotized cells stained with Fluoro-Jade B in the hippocampus and amygdala in rats Basic Protocol 4: Stereological quantification of injured or necrotized cells stained with Fluoro-Jade B in the hippocampus and amygdala regions in mice Basic Protocol 5: Brain fixation and histology processing Basic Protocol 6: Immunochemistry of principal neurons, interneurons, and newborn neurons Basic Protocol 7: Fluoro-Jade B staining of injured neurons.

A core scientific problem in the treatment of central nervous system diseases: newborn neurons

It has long been asserted that failure to recover from central nervous system diseases is due to the system's intricate structure and the regenerative incapacity of adult neurons. Yet over recent decades, numerous studies have established that endogenous neurogenesis occurs in the adult central nervous system, including humans'. This has challenged the long-held scientific consensus that the number of adult neurons remains constant, and that new central nervous system neurons cannot be created or renewed. Herein, we present a comprehensive overview of the alterations and regulatory mechanisms of endogenous neurogenesis following central nervous system injury, and describe novel treatment strategies that target endogenous neurogenesis and newborn neurons in the treatment of central nervous system injury. Central nervous system injury frequently results in alterations of endogenous neurogenesis, encompassing the activation, proliferation, ectopic migration, differentiation, and functional integration of endogenous neural stem cells. Because of the unfavorable local microenvironment, most activated neural stem cells differentiate into glial cells rather than neurons. Consequently, the injury-induced endogenous neurogenesis response is inadequate for repairing impaired neural function. Scientists have attempted to enhance endogenous neurogenesis using various strategies, including using neurotrophic factors, bioactive materials, and cell reprogramming techniques. Used alone or in combination, these therapeutic strategies can promote targeted migration of neural stem cells to an injured area, ensure their survival and differentiation into mature functional neurons, and facilitate their integration into the neural circuit. Thus can integration replenish lost neurons after central nervous system injury, by improving the local microenvironment. By regulating each phase of endogenous neurogenesis, endogenous neural stem cells can be harnessed to promote effective regeneration of newborn neurons. This offers a novel approach for treating central nervous system injury.

Metformin carbon dots enhance neurogenesis and neuroprotection in Alzheimer's disease: A potential nanomedicine approach

Alzheimer's disease (AD) is characterized by progressive cognitive decline due to neuronal damage and impaired neurogenesis. Preserving neuronal integrity and stimulating neurogenesis are promising therapeutic strategies to combat AD-related cognitive dysfunction. In this study, we synthesized metformin carbon dots (CMCDs) using a hydrothermal method with metformin hydrochloride and citric acid as precursors. Notably, we found that CMCDs were significantly more effective than metformin in promoting the differentiation of neural stem cells (NSCs) into functional neurons under amyloid-beta (Aβ) conditions. Moreover, CMCDs fostered NSCs proliferation, enhanced neurogenesis, reduced Aβ deposition, and inhibited glial cell activation. We also examined neuronal structure by assessing Map2/NF-H/PSD95/SYN expression in the hippocampus, finding that CMCDs robustly strengthened neuronal structure. These results suggest that CMCDs can cognitive dysfunction in AD and promote the proliferation and neurogenesis of NSCs, as well as ameliorate neuronal injury. Hence, CMCDs emerge as promising candidates for AD therapy, demonstrating superior efficacy compared to metformin alone, and offering novel insights into small molecule drug interventions for AD.

Identifying methamphetamine use predictors in HIV infection: Immune-dopaminergic signatures in peripheral leukocytes and the role of COMT genotype

The pursuit of translational biomarkers is complex due to the heterogeneous human pathophysiology, but critical for disease diagnosis, prognosis, monitoring therapeutic efficacy, and for patient stratification. In HIV-associated neurocognitive impairment (NCI), biomarkers that delineate the trajectory of neuropathogenesis and neurocognitive sequelae are critical, particularly considering confounders such as substance use, including Methamphetamine (METH). METH use is a significant health concern among persons living with HIV (PWH), aggravating cognitive deficits and neuroinflammation despite of antiretrovirals, introducing elements in the microenvironment that are fundamentally differerent in relation to non-METH users, such as high levels of dopamine (DA) affecting HIV-innate immune targets. Yet, current biomarkers do not detect these differences. We hypothesized that predefined DA-induced signatures detectable in peripheral blood leukocytes, can distinguish HIV+ METH users compared to HIV-negative or PWH that are non METH users. The elevated expression of CD8A, CREBBP, CCL5, and combinations of dopaminergic pathway transcripts clustered METH users with detectable CSF viral load and major depressive disorder (MDD), indicating neuroimmune-mechanistic links. Cathecol-o-methyltransferase (COMT) gene polymorphisms affecting DA metabolism improved the identification of PWH using METH with biomarkers. The results indicate that underlying immunedopaminergic mechanisms provide signatures and genotypes that can identify PWH that are METH users and their attributes.

Altered copper transport in oxidative stress-dependent brain endothelial barrier dysfunction associated with Alzheimer's disease

Oxidative stress and blood-brain barrier (BBB) disruption due to brain endothelial barrier dysfunction contribute to Alzheimer's Disease (AD), which is characterized by beta-amyloid (Aβ) accumulation in senile plaques. Copper (Cu) is implicated in AD pathology and its levels are tightly controlled by several Cu transport proteins. However, their expression and role in AD, particularly in relation to brain endothelial barrier function remains unclear. In this study, we examined the expression of Cu transport proteins in the brains of AD mouse models as well as their involvement in Aβ42-induced brain endothelial barrier dysfunction. We found that the Cu uptake transporter CTR1 was upregulated, while the Cu exporter ATP7A was downregulated in the hippocampus of AD mouse models and in Aβ42-treated human brain microvascular endothelial cells (hBMECs). In the 5xFAD AD mouse model, Cu levels (assessed by ICP-MS) were elevated in the hippocampus. Moreover, in cultured hBMECs, Aβ42-induced reactive oxygen species (ROS) production, ROS-dependent loss in barrier function (measured by transendothelial electrical resistance), and tyrosine phosphorylation of CDH5 were all inhibited by either a membrane permeable Cu chelator or by knocking down CTR1 expression. These findings suggest that dysregulated expression of Cu transport proteins may lead to intracellular Cu accumulation in the AD brain, and that Aβ42 promotes ROS-dependent brain endothelial barrier dysfunction and CDH5 phosphorylation in a CTR1-Cu-dependent manner. Our study uncovers the critical role of Cu transport proteins in oxidative stress-related loss of BBB integrity in AD.

Brain endothelial cell activation and dysfunction associate with and contribute to the development of enlarged perivascular spaces and cerebral small vessel disease

Multiple injurious stimuli to the brain's endothelium results in brain endothelial cell activation and dysfunction (BECact/dys) with upregulation of inflammatory signaling cascades and a decrease in bioavailable nitric oxide respectively. These injurious stimuli initiate a brain injury and a response to injury wound healing genetically programed cascade of events, which result in cellular remodeling of the neurovascular unit and blood-brain barrier with increased inflammation and permeability. These remodeling changes also include the perivascular spaces that become dilated to form enlarged perivascular spaces (EPVS) that may be identified noninvasively by magnetic resonance imaging. These EPVS are associated with and considered to be a biomarker for cerebral small vessel disease (SVD) and a dysfunctional glymphatic system with impaired removal of neurotoxic waste, which ultimately results in neurodegeneration with impaired cognition and dementia. The penultimate section discusses the understudied role of venous cerebral circulation in relation to EPVS, SVD, and the vascular contribution to cognitive impairment (VCID). The focus of this review will be primarily on BECact/dys that associates with and contributes to the development of EPVS, SVD, and impaired glymphatic system efflux. Importantly, BECact/dys may be a key piece of the puzzle to unlock this complicated story of EPVS and SVD. Multiple transmission electron micrographs and illustrations will be utilized to depict anatomical ultrastructure and allow for the discussion of multiple functional molecular cascades.

Postmortem Fatty Acid Abnormalities in the Cerebellum of Patients with Essential Tremor

Fatty acids play many critical roles in brain function but have not been investigated in essential tremor (ET), a frequent movement disorder suspected to involve cerebellar dysfunction. Here, we report a postmortem comparative analysis of fatty acid profiles by gas chromatography in the cerebellar cortex from ET patients (n = 15), Parkinson's disease (PD) patients (n = 15) and Controls (n = 17). Phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI)/ phosphatidylserine (PS) were separated by thin-layer chromatography and analyzed separately. First, the total amounts of fatty acids retrieved from the cerebellar cortex were lower in ET patients compared with PD patients, including monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). The diagnosis of ET was associated with lower cerebellar levels of saturated fatty acids (SFA) and PUFA (DHA and ARA) in the PE fraction specifically, but with a higher relative content of dihomo-γ-linolenic acid (DGLA; 20:3 ω-6) in the PC fraction. In contrast, a diagnosis of PD was associated with higher absolute concentrations of SFA, MUFA and ω-6 PUFA in the PI + PS fractions. However, relative PI + PS contents of ω-6 PUFA were lower in both PD and ET patients. Finally, linear regression analyses showed that the ω-3:ω-6 PUFA ratio was positively associated with age of death, but inversely associated with insoluble α-synuclein. Although it remains unclear how these FA changes in the cerebellum are implicated in ET or PD pathophysiology, they may be related to an ongoing neurodegenerative process or to dietary intake differences. The present findings provide a window of opportunity for lipid-based therapeutic nutritional intervention.

Sigma-1 receptor signaling: A potential therapeutic approach for ischemic stroke

Strokes constitute over 50% of all neurological diseases, standing as the foremost cause of physical and mental disability. Currently, there are no widely accepted gold standard treatments for ischemic strokes beyond intravenous thrombolysis and mechanical thrombectomy applied during the acute therapeutic window. Therefore, the need for novel treatments targeting crucial signaling mediators involved in ischemic stroke is of utmost importance. The sigma-1 receptor (S1R), a molecular chaperone located at mitochondria-associated endoplasmic reticulum membranes (MAM), has exhibited neuroprotective effects when modulated by synthetic and endogenous agents across various cerebrovascular diseases. In this review, we describe the emerging therapeutic role of S1R agonists and antagonists in regulating blood-brain barrier (BBB) dysfunction, neuroinflammation, and neurocognitive impairment following ischemic stroke.

Secretome from hypoxic mesenchymal stem cells as a potential therapy for ischemic stroke: Investigations on VEGF and GFAP expression

Ischemic stroke is a sudden onset of neurological deficit resulting from a blockage in cerebral blood vessels, which can lead to brain tissue damage, chronic disability, and increased risk of mortality. Secretome from hypoxic mesenchymal stem cells (SH-MSC) is a potential therapy to improve neurological deficit by increasing the expression of vascular endothelial growth factor (VEGF) and reducing glial fibrillary acidic protein (GFAP). These effects can reduce the infarction area of ischemic stroke. Therefore, the aim of this study was to analyze the effect of 150 μL and 300 μL SH-MSC injection on VEGF and GFAP expression as well as the improvement of infarction area in ischemic stroke animal model. A post-test-only experimental design with consecutive sampling was used, with Rattus norvegicus as subjects. Stromal mesenchymal stem cells (S-MSCs) were isolated from the umbilical cords of rats at 21 days of gestation. Secretome production by the S- MSCs was induced under a hypoxic condition, and subsequently isolated. The resultant secretome was administered to rats subjected to middle cerebral artery occlusion (MCAO) at doses of 150 μL (P1 group) and 300 μL (P2 group). The results showed that the infarction area was reduced in P1 (p<0.001) and P2 groups (p<0.001). SH-MSC at a dose of 300 μL increased the expression of VEGF (p=0.028) and reduced the expression of GFAP (p=0.001). In conclusion, secretome from hypoxic S-MSC could potentially improve ischemic stroke by upregulating VEGF expression and downregulating GFAP expression.

Deep brain stimulation on cognition in epilepsy: A concentration on learning and memory

Cognitive dysfunction is one of the common comorbidities of epilepsy. More than 60 % of epilepsy patients may experience impairment in learning, memory, attention, and executive control. At present, it can only control the symptoms of seizures, and there is no specific treatment for cognitive impairment. Deep brain stimulation (DBS) has been used to treat intractable epilepsy, with proven safety. Recently data suggests that DBS can not only improve the seizure control, but also improved cognitive function. This review summarizes the effects of DBS on cognitive impairment in epilepsy, including the current status and application of DBS, the influence of different DBS targets on brain of DBS on cognitive impairment in epilepsy, the possible mechanisms of DBS on cognitive impairment and its future prospects. It provides a theoretical basis for its further clinical application in epilepsy patients with cognitive dysfunction.

The impact of cardiovascular and cerebrovascular disease on the risk of dementia in rheumatoid arthritis: A mediation analysis

OBJECTIVE

To examine the role of cardiovascular disease (CVD) as a mediator in the pathway between rheumatoid arthritis (RA) and Alzheimer's disease and related dementias (ADRD).

METHODS

This retrospective population-based study included patients over 50 years of age with incident RA, who met the 1987 ACR criteria in 1980-2014. This cohort was matched 1:1 on age, sex and index year to comparators without RA. Information on CVD events was manually extracted from electronic health records. The relationships between RA, CVD and ADRD were examined using Cox proportional hazard models. Time dependent mediation analysis was used to examine the role of CVD as a mediator between RA and ADRD.

RESULTS

1754 individuals were included (877 persons with RA and 877 comparators without RA). During follow-up, 105 patients with RA and 102 individuals without RA developed ADRD; 444 patients with RA and 375 individuals without RA developed CVD. There was a non-significant association between RA and ADRD both without (aHR 1.27, 95 % CI 0.96, 1.69) and with (aHR 1.27, 95 % CI 0.95,1.68) CVD as a time dependent mediator. The mediation effect of any CVD on ADRD risk was not significant (p = 0.84). We found a significant interaction between RA and CVD on the risk of ADRD (aHR 1.95, 95 % CI 1.11, 3.42; p = 0.021).

CONCLUSIONS

The risk of ADRD in RA appears to be increased mainly in the presence of CVD. CVD was not a significant mediator on the risk of ADRD in RA. There was a significant synergistic effect of RA and CVD on ADRD risk.

The role of exercise in the prevention and treatment of Alzheimer's disease and mild cognitive impairments

Large retrospective cohort studies have consistently shown that people who exercise regularly are at a markedly reduced risk of dementias such as Alzheimer's Disease (AD). Animal studies have also found that exercise can prevent cognitive decline, and recent studies have identified possible mechanisms. However, randomized controlled trials of exercise interventions in AD and mild cognitive impairment have not reached a consensus regarding the efficacy of this treatment, hampering clinical adoption of this technique. This review examines these randomized controlled trials to assess potential causes for the variability in the measured outcomes. We posit that great variance in the methods used in these studies may account for some of the differences seen in outcomes. We determined that aerobic exercise led to the most benefits, that many cognitive domains improve with exercise, and that aerobic exercise enhances the ability for independent living. However, cognitive improvements were more pronounced and consistent in patients with mild cognitive impairment than AD, suggesting a narrow window of opportunity for exercise intervention.

Identification of isoquinoline alkaloids from Corydalis mucronifera and their acetylcholinesterase inhibitory effects

Four new spirobenzylisoquinoline mucroniferanines N - Q (1-4) and a rare chlorinated isoquinoline mucroniferanine R (5) were isolated from Corydalis mucronifera Maxim. Their structures were elucidated based on extensive spectroscopic data analysis of HRESIMS, 1D and 2D NMR, and their absolute configurations were confirmed by ECD data. The isolated compounds were evaluated for acetylcholinesterase (AChE) inhibitory activities. Mucroniferanine R showed significant activities with IC50 values of 0.78 μM compared to galanthamine (1.34 μM). The AChE inhibitory activity was further supported by the molecular docking analysis that exhibited the accommodation of mucroniferanine R in the active site of human AChE.

Cellular stress and epigenetic regulation in adult stem cells

Stem cells are a unique class of cells that possess the ability to differentiate and self-renew, enabling them to repair and replenish tissues. To protect and maintain the potential of stem cells, the cells and the environment surrounding these cells (stem cell niche) are highly responsive and tightly regulated. However, various stresses can affect the stem cells and their niches. These stresses are both systemic and cellular and can arise from intrinsic or extrinsic factors which would have strong implications on overall aging and certain disease states. Therefore, understanding the breadth of drivers, namely epigenetic alterations, involved in cellular stress is important for the development of interventions aimed at maintaining healthy stem cells and tissue homeostasis. In this review, we summarize published findings of epigenetic responses to replicative, oxidative, mechanical, and inflammatory stress on various types of adult stem cells.

Effect of bioactive extracts from Eucalyptus globulus leaves in experimental models of Alzheimer's disease

Current therapies for Alzheimer's disease (AD) do not delay its progression, therefore, novel disease-modifying strategies are urgently needed. Recently, an increasing number of compounds from natural origin with protective properties against AD have been identified. Mixtures or extracts obtained from natural products containing several bioactive compounds have multifunctional properties and have drawn the attention because multiple AD pathways can be simultaneously modulated. This study evaluated the in vitro and in vivo effect of the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and an extract obtained from the hydrodistillation residual water (HRW). It was observed that EO and HRW have anti-inflammatory effect in brain immune cells modeling AD, namely lipopolysaccharide (LPS)- and amyloid-beta (Aβ)-stimulated microglia. In cell models that mimic AD-related neuronal dysfunction, HRW attenuated Aβ secretion and Aβ-induced mitochondrial dysfunction. Since the HRW's major components did not cross the blood-brain barrier, both EO and HRW were administered to the APP/PS1 transgenic AD mouse model by an intranasal route, which reduced cortical and hippocampal Aβ levels, and to rescue memory deficits and anxiety-like behaviors. Finally, HRW and EO were found to regulate cholesterol levels in aged mice after intranasal administration, suggesting that these extracts can reduce hypercholesterolemia and avoid risk for AD development. Overall, findings support a protective role of E. globulus extracts against AD‑like pathology and cognitive impairment highlighting the underlying mechanisms. These extracts obtained from underused forest biomass could be useful to develop nutraceutical supplements helpful to avoid AD risk and to prevent its progression.

Differential regulation of brain microvessel transcriptome and brain metabolome by western and heart-healthy dietary patterns in Ossabaw pigs

Diet is a potentially modifiable neurodegenerative disease risk factor. We studied the effects of a typical Western diet (WD; high in refined carbohydrates, cholesterol and saturated fat), relative to a heart-healthy diet (HHD; high in unrefined carbohydrates, polyunsaturated fat and fiber, and low in cholesterol) on brain microvessel transcriptomics and brain metabolomics of the temporal region in Ossabaw minipigs. Thirty-two pigs (16 male and 16 females) were fed a WD or HHD starting at the age of 4 months for a period of 6 months. The WD and HHD were isocaloric and had a similar macronutrient content but differed in macronutrient quality. Within each dietary group, half of the pigs also received atorvastatin. Relative to HHD-fed pigs, WD-fed pigs had 175 genes differentially expressed (fold change > 1.3, FDR < 0.05) by diet, 46 upregulated and 129 downregulated. Gene Set Enrichment Analysis identified 22 gene sets enriched in WD-fed pigs, comprising pathways related to inflammation, angiogenesis, and apoptosis, and 53 gene sets enriched in the HHD-fed pigs, including cell energetics, neurotransmission, and inflammation resolution pathways. Metabolite analysis showed enrichment in arginine, tyrosine, and lysine in WD-fed pigs, and ergothioneine and S-adenosyl methionine in HHD-fed pigs. Atorvastatin treatment did not affect gene expression. These results suggest a likely contribution of diet to brain pathologies characterized by neuroinflammation and neurodegeneration.

Brain-immune interactions: implication for cognitive impairments in Alzheimer's disease and autoimmune disorders

Progressive memory loss and cognitive dysfunction, encompassing deficits in learning, memory, problem solving, spatial reasoning, and verbal expression, are characteristics of Alzheimer's disease and related dementia. A wealth of studies has described multiple roles of the immune system in the development or exacerbation of dementia. Individuals with autoimmune disorders can also develop cognitive dysfunction, a phenomenon termed "autoimmune dementia." Together, these findings underscore the pivotal role of the neuroimmune axis in both Alzheimer's disease and related dementia and autoimmune dementia. The dynamic interplay between adaptive and innate immunity, both in and outside the brain, significantly affects the etiology and progression of these conditions. Multidisciplinary research shows that cognitive dysfunction arises from a bidirectional relationship between the nervous and immune systems, though the specific mechanisms that drive cognitive impairments are not fully understood. Intriguingly, this reciprocal regulation occurs at multiple levels, where neuronal signals can modulate immune responses, and immune system-related processes can influence neuronal viability and function. In this review, we consider the implications of autoimmune responses in various autoimmune disorders and Alzheimer's disease and explore their effects on brain function. We also discuss the diverse cellular and molecular crosstalk between the brain and the immune system, as they may shed light on potential triggers of peripheral inflammation, their effect on the integrity of the blood-brain barrier, and brain function. Additionally, we assess challenges and possibilities associated with developing immune-based therapies for the treatment of cognitive decline.

Decoding senescence of aging single cells at the nexus of biomaterials, microfluidics, and spatial omics

Aging has profound effects on the body, most notably an increase in the prevalence of several diseases. An important aging hallmark is the presence of senescent cells that no longer multiply nor die off properly. Another characteristic is an altered immune system that fails to properly self-surveil. In this multi-player aging process, cellular senescence induces a change in the secretory phenotype, known as senescence-associated secretory phenotype (SASP), of many cells with the intention of recruiting immune cells to accelerate the clearance of these damaged senescent cells. However, the SASP phenotype results in inducing secondary senescence of nearby cells, resulting in those cells becoming senescent, and improper immune activation resulting in a state of chronic inflammation, called inflammaging, in many diseases. Senescence in immune cells, termed immunosenescence, results in further dysregulation of the immune system. An interdisciplinary approach is needed to physiologically assess aging changes of the immune system at the cellular and tissue level. Thus, the intersection of biomaterials, microfluidics, and spatial omics has great potential to collectively model aging and immunosenescence. Each of these approaches mimics unique aspects of the body undergoes as a part of aging. This perspective highlights the key aspects of how biomaterials provide non-cellular cues to cell aging, microfluidics recapitulate flow-induced and multi-cellular dynamics, and spatial omics analyses dissect the coordination of several biomarkers of senescence as a function of cell interactions in distinct tissue environments. An overview of how senescence and immune dysregulation play a role in organ aging, cancer, wound healing, Alzheimer's, and osteoporosis is included. To illuminate the societal impact of aging, an increasing trend in anti-senescence and anti-aging interventions, including pharmacological interventions, medical procedures, and lifestyle changes is discussed, including further context of senescence.

Housing Environmental Enrichment, Lifestyles, and Public Health Indicators of Neurogenesis in Humans: A Pilot Study

BACKGROUND

In response to the rising mental health concerns and cognitive decline associated with the human brain's neurogenesis, which continues until the tenth decade of life but declines with age and is suppressed by poor environments, this pilot study investigates how physical environments may influence public health proxy measures of neurogenesis in humans. This pilot study focuses on the residential environment where people spend most of their time and age in place, exploring the dependency of depression, anxiety, and cognitive impairment variations on spatial and lifestyle variables.

METHODS

A total of 142 healthy adults in England completed a survey consisting of PHQ-8, GAD-7, and CFI questionnaires and other questions developed to capture the variance in spatial and lifestyle factors such as time spent at home, house type layout complexity, spaciousness, physical activity, routine and spatial novelty, and perceived loneliness.

RESULTS

Extensive time spent at home has adverse effects on all measures, while multi-storey houses perform better than single-story houses with positive correlations with physical activity and spatial novelty. Separate regression models on the variance in depression, as the most salient dependent variable and reliably associated with neurogenesis, reveal that getting out of the house explains 20.5% of the variance in depression symptoms. At the scale of the house, multi-storey houses explain 16.5% of the variance. Both percentages are closer to the effect of loneliness, which we found to explain 26.6% of the variance in depression.

CONCLUSIONS

The built environment appears to be significantly associated with changes in cognitive function and mental health symptoms associated with neurogenesis. This pilot study shows the equally important effect of physical and social enrichment, offering critically needed insights for neuroarchitecture and brain health research that is interested in public health.

Multimodal beneficial effects of BNN27, a nerve growth factor synthetic mimetic, in the 5xFAD mouse model of Alzheimer's disease

Alzheimer's Disease (AD) is an incurable and debilitating progressive, neurodegenerative disorder which is the leading cause of dementia worldwide. Neuropathologically, AD is characterized by the accumulation of Aβ amyloid plaques in the microenvironment of brain cells and neurovascular walls, chronic neuroinflammation, resulting in neuronal and synaptic loss, myelin and axonal failure, as well as significant reduction in adult hippocampal neurogenesis. The hippocampal formation is particularly vulnerable to this degenerative process, due to early dysfunction of the cholinergic circuit. Neurotrophic factors consist major regulatory molecules and their decline in AD is considered as an important cause of disease onset and progression. Novel pharmacological approaches are targeting the downstream pathways controlled by neurotrophins, such as nerve growth factor (NGF) receptors, TrkA and p75NTR, which enhance hippocampal neurogenic capacity and neuroprotective mechanisms, and potentially counteract the neurotoxic effects of amyloid deposition. BNN27 is a non-toxic, newly developed 17-spiro-steroid analog, penetrating the blood-brain-barrier (BBB) and mimicking the neuroprotective effects of NGF, acting as selective activator of its receptors, both TrkA and p75NTR, thus promoting survival of various neuronal cell types. Our present research aims at determining whether and which aspects of the AD-related pathology, BNN27 is able to alleviate, exploring the cellular and molecular AD components and link these changes with improvements in the cognitive performance of an animal AD model, the 5xFAD mice. Our results clearly indicate that BNN27 administration significantly reduced amyloid-β load in whole brain of the animals, enhanced adult hippocampal neurogenesis, restored cholinergic function and synaptogenesis, reducing inflammatory activation and leading to significant restoration of cognitive functions. BNN27 may represent a new lead multimodal molecule with neuroprotective, neurogenic and anti-neuroinflammatory actions for developing druggable anti-Alzheimeric agents. Proteomics data are available via ProteomeXchange with the identifier PXD044699.

Study on the therapeutic potential of induced neural stem cells for Alzheimer's disease in mice

Induced neural stem cells (iNSCs), which have similar properties to neural stem cells and are able to self-proliferate and differentiate into neural cell lineages, are expected to be potential cells for the treatment of neurodegeneration disease. However, cell therapy based on iNSCs transplantation is limited by the inability to acquire sufficient quantities of iNSCs. Previous studies have found that mouse and human fibroblasts can be directly reprogrammed into iNSCs with a single factor, Sox2. Here, we induced mouse embryonic fibroblasts (MEFs) into iNSCs by combining valproic acid (VPA) with the induction factor Sox2, and the results showed that VPA significantly improved the conversion efficiency of fibroblasts to iNSCs. The iNSCs exhibited typical neurosphere-like structures that can express NSCs markers, such as Sox2, Nestin, Sox1, and Zbtb16, and could differentiate into neurons, astrocytes, and oligodendrocytes in vitro. Subsequently, the iNSCs were stereotactically transplanted into the hippocampus of APP/PS1 double transgenic mice (AD mice). Post-transplantation, the iNSCs showed long-term survival, migrated over long distances, and differentiated into multiple types of functional neurons and glial cells in vivo. Importantly, the cognitive abilities of APP/PS1 mice transplanted with iNSCs exhibited significant functional recovery. These findings suggest that VPA enhances the conversion efficiency of fibroblasts into iNSCs when used in combination with Sox2, and iNSCs hold promise as a potential donor material for transplantation therapy in Alzheimer's disease.

Engineered bio-functional material-based nerve guide conduits for optic nerve regeneration: a view from the cellular perspective, challenges and the future outlook

Nerve injuries can be tantamount to severe impairment, standard treatment such as the use of autograft or surgery comes with complications and confers a shortened relief. The mechanism relevant to the regeneration of the optic nerve seems yet to be fully uncovered. The prevailing rate of vision loss as a result of direct or indirect insult on the optic nerve is alarming. Currently, the use of nerve guide conduits (NGC) to some extent has proven reliable especially in rodents and among the peripheral nervous system, a promising ground for regeneration and functional recovery, however in the optic nerve, this NGC function seems quite unfamous. The insufficient NGC application and the unabridged regeneration of the optic nerve could be a result of the limited information on cellular and molecular activities. This review seeks to tackle two major factors (i) the cellular and molecular activity involved in traumatic optic neuropathy and (ii) the NGC application for the optic nerve regeneration. The understanding of cellular and molecular concepts encompassed, ocular inflammation, extrinsic signaling and intrinsic signaling for axon growth, mobile zinc role, Ca2+ factor associated with the optic nerve, alternative therapies from nanotechnology based on the molecular information and finally the nanotechnological outlook encompassing applicable biomaterials and the use of NGC for regeneration. The challenges and future outlook regarding optic nerve regenerations are also discussed. Upon the many approaches used, the comprehensive role of the cellular and molecular mechanism may set grounds for the efficient application of the NGC for optic nerve regeneration.

Stem cell therapy in Alzheimer's disease: current status and perspectives

An incurable neurogenerative illness, Alzheimer's disease, is the cause of most global health, medical, and social disasters. The two main symptoms are cognitive impairment and neuronal loss. Current medications that target tau protein tangles and Aβ plaques are not very effective because they only slow the symptoms of AD and do not repair damaged cells. Stem cell-based treatments, however, present an alternative strategy in the treatment of AD. They have the capacity to divide into specialized adult cells, have self-renewal abilities, and multiplication. Stem cells can now be employed as a donor source for cell therapy due to developments in stem cell technology. This review covers preclinical and clinical updates on studies based on targeting the tau protein tangles and Aβ plaque, as well as four types of stem cells employed in AD treatment. The review also outlines the two basic pathologic aspects, tau protein tangles and Aβ plaques, of AD.

Stearoyl-CoA desaturase-1: a potential therapeutic target for neurological disorders

Disturbances in the fatty acid lipidome are increasingly recognized as key drivers in the progression of various brain disorders. In this review article, we delve into the impact of Δ9 fatty acid desaturases, with a particular focus on stearoyl-CoA desaturase-1 (SCD1), within the setting of neuroinflammation, neurodegeneration, and brain repair. Over the past years, it was established that inhibition or deficiency of SCD1 not only suppresses neuroinflammation but also protects against neurodegeneration in conditions such as multiple sclerosis, Alzheimer's disease, and Parkinson's disease. This protective effect is achieved through different mechanisms including enhanced remyelination, reversal of synaptic and cognitive impairments, and mitigation of α-synuclein toxicity. Intriguingly, metabolic rerouting of fatty acids via SCD1 improves the pathology associated with X-linked adrenoleukodystrophy, suggesting context-dependent benign and harmful effects of SCD1 inhibition in the brain. Here, we summarize and discuss the cellular and molecular mechanisms underlying both the beneficial and detrimental effects of SCD1 in these neurological disorders. We explore commonalities and distinctions, shedding light on potential therapeutic challenges. Additionally, we touch upon future research directions that promise to deepen our understanding of SCD1 biology in brain disorders and potentially enhance the clinical utility of SCD1 inhibitors.

Exercise-conditioned plasma ameliorates postoperative cognitive dysfunction by activating hippocampal cholinergic circuit and enhancing BDNF/TrkB signaling

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a prevalent complication following anesthesia and surgery, particularly in the elderly, leading to increased mortality and reduced quality of life. Despite its prevalence, there are no effective clinical treatments. Exercise has shown cognitive benefits in aging and various diseases, which can be transferred to sedentary animals through plasma. However, it is unclear if exercise-conditioned plasma can replicate these benefits in the context of POCD.

METHODS

Sixteen-month-old male C57BL/6J mice underwent 30 days of voluntary running wheel training or received systemic administration of exercise-conditioned plasma, followed by tibial fracture surgery under general anesthesia at 17 months of age. Cognitive performance, hippocampal synaptic deficits, neuroinflammation, BDNF/TrkB signaling, and medial septum (MS)-hippocampal cholinergic activity were evaluated through immunohistochemical staining, transmission electron microscopy, Western blotting, and biochemical assays. To investigate the role of hippocampal BDNF signaling and cholinergic activity in the therapeutic effects, the TrkB antagonist ANA-12 and the cholinergic receptor muscarinic 1 (CHRM1) antagonist trihexyphenidyl (THP) were administered via intraperitoneal injection, and adeno-associated virus (AAV) vectors expressing Chrm1 shRNA were delivered via intrahippocampal stereotaxic microinjection.

RESULTS

Exercise-conditioned plasma mimicked the benefits of exercise, alleviating cognitive decline induced by anesthesia/surgery, restoring hippocampal synapse formation and levels of regulators for synaptic plasticity, inhibiting neuroinflammatory responses to surgery by microglia and astrocytes, augmenting BDNF production and TrkB phosphorylation in hippocampal neurons, astrocytes, and microglia, upregulating MS expression of choline acetyltransferase (CHAT) and hippocampal expression of CHRM1 in neurons and astrocytes, and enhancing hippocampal cholinergic innervation and acetylcholine release. Conversely, ANA-12 administration blocked TrkB activation and reduced the protective effects on cognition, synaptic deficits, and neuroinflammatory reactivity of glial cells post-surgery. Similarly, THP administration or intrahippocampal delivery of AAV-Chrm1 shRNA inhibited the activation of the hippocampal cholinergic circuit by exercise plasma, negating the cognitive and neuropathological benefits and reducing BDNF/TrkB signaling enhancements.

CONCLUSION

Exercise-conditioned plasma can replicate the protective effects of exercise against anesthesia/surgery-induced neuroinflammation, synaptic, and cognitive impairments, at least partly, through CHRM1-dependent regulation of hippocampal cholinergic activity and BDNF/TrkB signaling.