Galectin 3-binding protein suppresses amyloid-β production by modulating β-cleavage of amyloid precursor protein

Extracellular vesicles from human-induced pluripotent stem cell-derived neural stem cells alleviate proinflammatory cascades within disease-associated microglia in Alzheimer's disease

As current treatments for Alzheimer's disease (AD) lack disease-modifying interventions, novel therapies capable of restraining AD progression and maintaining better brain function have great significance. Anti-inflammatory extracellular vesicles (EVs) derived from human induced pluripotent stem cell (hiPSC)-derived neural stem cells (NSCs) hold promise as a disease-modifying biologic for AD. This study directly addressed this issue by examining the effects of intranasal (IN) administrations of hiPSC-NSC-EVs in 3-month-old 5xFAD mice. IN administered hiPSC-NSC-EVs incorporated into microglia, including plaque-associated microglia, and encountered astrocyte soma and processes in the brain. Single-cell RNA sequencing revealed transcriptomic changes indicative of diminished activation of microglia and astrocytes. Multiple genes linked to disease-associated microglia, NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3)-inflammasome and interferon-1 (IFN-1) signalling displayed reduced expression in microglia. Adding hiPSC-NSC-EVs to cultured human microglia challenged with amyloid-beta oligomers resulted in similar effects. Astrocytes also displayed reduced expression of genes linked to IFN-1 and interleukin-6 signalling. Furthermore, the modulatory effects of hiPSC-NSC-EVs on microglia in the hippocampus persisted 2 months post-EV treatment without impacting their phagocytosis function. Such effects were evidenced by reductions in microglial clusters and inflammasome complexes, concentrations of mediators, and end products of NLRP3 inflammasome activation, the expression of genes and/or proteins involved in the activation of p38/mitogen-activated protein kinase and IFN-1 signalling, and unaltered phagocytosis function. The extent of astrocyte hypertrophy, amyloid-beta plaques, and p-tau were also reduced in the hippocampus. Such modulatory effects of hiPSC-NSC-EVs also led to better cognitive and mood function. Thus, early hiPSC-NSC-EV intervention in AD can maintain better brain function by reducing adverse neuroinflammatory signalling cascades, amyloid-beta plaque load, and p-tau. These results reflect the first demonstration of the efficacy of hiPSC-NSC-EVs to restrain neuroinflammatory signalling cascades in an AD model by inducing transcriptomic changes in activated microglia and reactive astrocytes.

Revisiting the role of phospholipases in alzheimer's: crosstalk with processed food

Phospholipases such as phospholipase-A, phospholipase-B, phospholipase-C and phospholipase-D are important functional enzymes of the cell membrane responsible for a variety of functions such as signal transduction, production of lipid mediators, metabolite digestion and playing a pathological role in central nervous system diseases. Phospholipases have shown an association with Alzheimer's disease and these enzymes have found a correlation with several metabolic pathways that can lead to the activation of inflammatory signals via astrocytes and microglial cells. We also highlighted unhealthy practices like smoking and consuming processed foods, rich in nitroso compounds and phosphatidic acid, which contribute to neuronal damage in AD through phospholipases. A few therapeutic approaches such as the use of inhibitors of phospholipase-D,phospholipase A2 as well as autophagy-mediated inhibition have been discussed to control the onset of AD. This paper serves as a crosstalk between phospholipases and their role in neurodegenerative pathways as well as their influence on other biomolecules of lipid membranes, which are acquired through unhealthy diets and possible methods to treat these anomalies occurring due to their metabolic disorder involving phospholipases acting as major signaling molecules.

Skin-brain axis in Alzheimer's disease - Pathologic, diagnostic, and therapeutic implications: A Hypothetical Review

The dynamic interaction between the brain and the skin is termed the 'skin-brain axis.' Changes in the skin not only reflect conditions in the brain but also exert direct and indirect effects on the brain. Interestingly, the connection between the skin and brain is crucial for understanding aging and neurodegenerative diseases. Several studies have shown an association between Alzheimer's disease (AD) and various skin disorders, such as psoriasis, bullous pemphigoid, and skin cancer. Previous studies have shown a significantly increased risk of new-onset AD in patients with psoriasis. In contrast, skin cancer may reduce the risk of developing AD. Accumulating evidence suggests an interaction between skin disease and AD; however, AD-associated pathological changes mediated by the skin-brain axis are not yet clearly defined. While some studies have reported on the diagnostic implications of the skin-brain axis in AD, few have discussed its potential therapeutic applications. In this review, we address the pathological changes mediated by the skin-brain axis in AD. Furthermore, we summarize (1) the diagnostic implications elucidated through the role of the skin-brain axis in AD and (2) the therapeutic implications for AD based on the skin-brain axis. Our review suggests that a potential therapeutic approach targeting the skin-brain axis will enable significant advances in the treatment of AD.

Intranasally Administered EVs from hiPSC-derived NSCs Alter the Transcriptomic Profile of Activated Microglia and Conserve Brain Function in an Alzheimer's Model

Antiinflammatory extracellular vesicles (EVs) derived from human induced pluripotent stem cell (hiPSC)-derived neural stem cells (NSCs) hold promise as a disease-modifying biologic for Alzheimer's disease (AD). This study directly addressed this issue by examining the effects of intranasal administrations of hiPSC-NSC-EVs to 3-month-old 5xFAD mice. The EVs were internalized by all microglia, which led to reduced expression of multiple genes associated with disease-associated microglia, inflammasome, and interferon-1 signaling. Furthermore, the effects of hiPSC-NSC-EVs persisted for two months post-treatment in the hippocampus, evident from reduced microglial clusters, inflammasome complexes, and expression of proteins and/or genes linked to the activation of inflammasomes, p38/mitogen-activated protein kinase, and interferon-1 signaling. The amyloid-beta (Aβ) plaques, Aβ-42, and phosphorylated-tau concentrations were also diminished, leading to better cognitive and mood function in 5xFAD mice. Thus, early intervention with hiPSC-NSC-EVs in AD may help maintain better brain function by restraining the progression of adverse neuroinflammatory signaling cascades.

Identification and Characterization of Synaptic Vesicle Membrane Protein VAT-1 Homolog as a New Catechin-Binding Protein

(-)-Epigallocatechin-3-gallate (EGCg), a major constituent of green tea extract, is well-known to exhibit many beneficial actions for human health by interacting with numerous proteins. In this study we identified synaptic vesicle membrane protein VAT-1 homolog (VAT1) as a novel EGCg-binding protein in human neuroglioma cell extracts using a magnetic pull-down assay and LC-tandem mass spectrometry. We prepared recombinant human VAT1 and analyzed its direct binding to EGCg and its alkylated derivatives using surface plasmon resonance. For EGCg and the derivative NUP-15, we measured an association constant of 0.02-0.85 ×103 M-1s-1 and a dissociation constant of nearly 8 × 10-4 s-1. The affinity Km(affinity) of their binding to VAT1 was in the 10-20 µM range and comparable with that of other EGCg-binding proteins reported previously. Based on the common structure of the compounds, VAT1 appeared to recognize a catechol or pyrogallol moiety around the B-, C- and G-rings of EGCg. Next, we examined whether VAT1 mediates the effects of EGCg and NUP-15 on expression of neprilysin (NEP). Treatments of mock cells with these compounds upregulated NEP, as observed previously, whereas no effect was observed in the VAT1-overexpressing cells, indicating that VAT1 prevented the effects of EGCg or NUP-15 by binding to and inactivating them in the cells overexpressing VAT1. Further investigation is required to determine the biological significance of the VAT1-EGCg interaction.

Extracellular vesicles from hiPSC-NSCs can prevent peripheral inflammation-induced cognitive dysfunction with inflammasome inhibition and improved neurogenesis in the hippocampus

Extracellular vesicles (EVs) released by human induced pluripotent stem cell-derived neural stem cells (hiPSC-NSCs) are enriched with miRNAs and proteins capable of mediating robust antiinflammatory activity. The lack of tumorigenic and immunogenic properties and ability to permeate the entire brain to incorporate into microglia following intranasal (IN) administrations makes them an attractive biologic for curtailing chronic neuroinflammation in neurodegenerative disorders. We tested the hypothesis that IN administrations of hiPSC-NSC-EVs can alleviate chronic neuroinflammation and cognitive impairments induced by the peripheral lipopolysaccharide (LPS) challenge. Adult male, C57BL/6J mice received intraperitoneal injections of LPS (0.75 mg/kg) for seven consecutive days. Then, the mice received either vehicle (VEH) or hiPSC-NSC-EVs (~ 10 × 109 EVs/administration, thrice over 6 days). A month later, mice in all groups were investigated for cognitive function with behavioral tests and euthanized for histological and biochemical studies. Mice receiving VEH after LPS displayed deficits in associative recognition memory, temporal pattern processing, and pattern separation. Such impairments were associated with an increased incidence of activated microglia presenting NOD-, LRR-, and pyrin domain containing 3 (NLRP3) inflammasomes, elevated levels of NLRP3 inflammasome mediators and end products, and decreased neurogenesis in the hippocampus. In contrast, the various cognitive measures in mice receiving hiPSC-NSC-EVs after LPS were closer to naive mice. Significantly, these mice displayed diminished microglial activation, NLRP3 inflammasomes, proinflammatory cytokines, and a level of neurogenesis matching age-matched naïve controls. Thus, IN administrations of hiPSC-NSC-EVs are an efficacious approach to reducing chronic neuroinflammation-induced cognitive impairments.

Long term administration of loquat leaves and their major component, ursolic acid, attenuated endogenous amyloid-β burden and memory impairment

Loquat (Eriobotrya japonica) leaves contain many bioactive components such as ursolic acid (UA) and amygdalin. We investigated the effects of loquat leaf powder and methanol extract in human neuroglioma H4 cells stably expressing the Swedish-type APP695 (APPNL-H4 cells) and C57BL/6 J mice. Surprisingly, the extract greatly enhanced cellular amyloid-beta peptide (Aβ) 42 productions in APPNL-H4 cells. Administration of leaf powder increased Aβ42 levels after 3 months and decreased levels after 12 months compared to control mice. Leaf powder had no effect on working memory after 3 months, but improved working memory after 12 months. Administration of UA decreased Aβ42 and P-tau levels and improved working memory after 12 months, similar to the administration of leave powder for 12 months. Amygdalin enhanced cellular Aβ42 production in APPNL-H4 cells, which was the same as the extract. Three-month administration of amygdalin increased Aβ42 levels slightly but did not significantly increase them, which is similar to the trend observed with the administration of leaf powder for 3 months. UA was likely the main compound contained in loquat leaves responsible for the decrease in intracerebral Aβ42 and P-tau levels. Also, amygdalin might be one of the compounds responsible for the transiently increased intracerebral Aβ42 levels.

Lysosomal proteomics reveals mechanisms of neuronal apoE4associated lysosomal dysfunction

ApoE4 is the primary risk factor for Alzheimer's Disease. While apoE is primarily expressed by astrocytes, AD pathology including endosomal abnormalities and mitochondrial dysfunction first occurs in neurons. Lysosomes are poised at the convergence point between these features. We find that apoE4-expressing cells exhibit lysosomal alkalinization, reduced lysosomal proteolysis, and impaired mitophagy. To identify driving factors for this lysosomal dysfunction, we performed quantitative lysosomal proteome profiling. This revealed that apoE4 expression results in lysosomal depletion of Lgals3bp and accumulation of Tmed5 in both Neuro-2a cells and postmitotic human neurons. Modulating the expression of both proteins affected lysosomal function, with Tmed5 knockdown rescuing lysosomal alkalinization in apoE4 cells, and Lgals3bp knockdown causing lysosomal alkalinization and reduced lysosomal density in apoE3 cells. Taken together, our work reveals that apoE4 exerts gain-of-toxicity by alkalinizing the lysosomal lumen, pinpointing lysosomal Tmed5 accumulation and Lgals3bp depletion as apoE4-associated drivers for this phenotype.

Reprogramming iPSCs to study age-related diseases: Models, therapeutics, and clinical trials

The unprecedented rise in life expectancy observed in the last decades is leading to a global increase in the ageing population, and age-associated diseases became an increasing societal, economic, and medical burden. This has boosted major efforts in the scientific and medical research communities to develop and improve therapies to delay ageing and age-associated functional decline and diseases, and to expand health span. The establishment of induced pluripotent stem cells (iPSCs) by reprogramming human somatic cells has revolutionised the modelling and understanding of human diseases. iPSCs have a major advantage relative to other human pluripotent stem cells as their obtention does not require the destruction of embryos like embryonic stem cells do, and do not have a limited proliferation or differentiation potential as adult stem cells. Besides, iPSCs can be generated from somatic cells from healthy individuals or patients, which makes iPSC technology a promising approach to model and decipher the mechanisms underlying the ageing process and age-associated diseases, study drug effects, and develop new therapeutic approaches. This review discusses the advances made in the last decade using iPSC technology to study the most common age-associated diseases, including age-related macular degeneration (AMD), neurodegenerative and cardiovascular diseases, brain stroke, cancer, diabetes, and osteoarthritis.

The QPLEX™ Plus Assay Kit for the Early Clinical Diagnosis of Alzheimer's Disease

We recently developed a multiplex diagnostic kit, QPLEX™ Alz plus assay kit, which captures amyloid-β1-40, galectin-3 binding protein, angiotensin-converting enzyme, and periostin simultaneously using microliters of peripheral blood and utilizes an optimized algorithm for screening Alzheimer's disease (AD) by correlating with cerebral amyloid deposition. Owing to the demand for early AD detection, we investigate the potential of our kit for the early clinical diagnosis of AD. A total of 1395 participants were recruited, and their blood samples were analyzed with the QPLEX™ kit. The average of QPLEX™ algorithm values in each group increased gradually in the order of the clinical progression continuum of AD: cognitively normal (0.382 ± 0.150), subjective cognitive decline (0.452 ± 0.130), mild cognitive impairment (0.484 ± 0.129), and AD (0.513 ± 0.136). The algorithm values between each group showed statistically significant differences among groups divided by Mini-Mental State Examination and Clinical Dementia Rating. The QPLEX™ algorithm values could be used to distinguish the clinical continuum of AD or cognitive function. Because blood-based diagnosis is more accessible, convenient, and cost- and time-effective than cerebral spinal fluid or positron emission tomography imaging-based diagnosis, the QPLEX™ kit can potentially be used for health checkups and the early clinical diagnosis of AD.

The role of GPLD1 in chronic diseases

Glycosylphosphatidylinositol-specific phospholipase D (GPLD1) is a specific enzyme for glycosylphosphatidylinositol (GPI) anchors, thereby exerting its biological functions by cleaving membrane-associated GPI molecules. GPLD1 is abundant in serum, with a concentration of approximately 5-10 µg/mL. Previous studies have demonstrated that GPLD1 plays a crucial role in the pathogenesis of numerous chronic diseases including disorders of lipid and glucose metabolism, cancer, and neurological disorders. In the present study, we reviewed the structure, functions, and localization of GPLD1 in chronic diseases, as well as exercise-mediated regulation of GPLD1, thus providing a theoretical support to develop GPLD1 as a new therapeutic target for chronic diseases.

A characteristic N-glycopeptide signature associated with diabetic cognitive impairment identified in a longitudinal cohort study

BACKGROUND

Identifying a biomarker for the decline in cognitive function in patients with diabetes is important. Therefore, we aimed to identify the N-glycopeptides on plasma proteins associated with diabetic cognitive impairment in participants in a longitudinal study using N-glycoproteomics.

METHODS

We used samples from the 3-year SONIC (Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians) longitudinal cohort study of older Japanese people in the general population. First, we placed the participants with diabetes into two groups: those that did or did not have cognitive decline over a 6-year period. Next, their plasma protein profiles were compared between baseline and the 6-year time point using two-dimensional fluorescence difference gel electrophoresis. Finally, an N-glycoproteomic study of the focused proteins was performed using an enrichment technique and liquid chromatography-tandem mass spectrometry.

RESULTS

Approximately 500 N-glycopeptides, derived from 18 proteins, were identified in each sample, from among which we identified the N-glycopeptides that were associated with diabetic cognitive impairment using multivariate analysis. We found that N-glycopeptides with sialylated tri- or tetra-antennary glycans on alpha-2-macroglobulin, clusterin, serum paraoxonase/arylesterase 1, and haptoglobin were less abundant, whereas 3-sialylated tri-antennary N-glycopeptides on serotransferrin were more abundant.

CONCLUSION

N-glycopeptides with sialylated multi-antennary glycans comprise a characteristic signature associated with diabetic cognitive impairment.

GENERAL SIGNIFICANCE

The characterized N-glycopeptides represent potential biomarker candidates for diabetic cognitive impairment.

Co-Expression Network Analysis Identifies Molecular Determinants of Loneliness Associated with Neuropsychiatric and Neurodegenerative Diseases

Loneliness and social isolation are detrimental to mental health and may lead to cognitive impairment and neurodegeneration. Although several molecular signatures of loneliness have been identified, the molecular mechanisms by which loneliness impacts the brain remain elusive. Here, we performed a bioinformatics approach to untangle the molecular underpinnings associated with loneliness. Co-expression network analysis identified molecular 'switches' responsible for dramatic transcriptional changes in the nucleus accumbens of individuals with known loneliness. Loneliness-related switch genes were enriched in cell cycle, cancer, TGF-β, FOXO, and PI3K-AKT signaling pathways. Analysis stratified by sex identified switch genes in males with chronic loneliness. Male-specific switch genes were enriched in infection, innate immunity, and cancer-related pathways. Correlation analysis revealed that loneliness-related switch genes significantly overlapped with 82% and 68% of human studies on Alzheimer's (AD) and Parkinson's diseases (PD), respectively, in gene expression databases. Loneliness-related switch genes, BCAM, NECTIN2, NPAS3, RBM38, PELI1, DPP10, and ASGR2, have been identified as genetic risk factors for AD. Likewise, switch genes HLA-DRB5, ALDOA, and GPNMB are known genetic loci in PD. Similarly, loneliness-related switch genes overlapped in 70% and 64% of human studies on major depressive disorder and schizophrenia, respectively. Nine switch genes, HLA-DRB5, ARHGAP15, COL4A1, RBM38, DMD, LGALS3BP, WSCD2, CYTH4, and CNTRL, overlapped with known genetic variants in depression. Seven switch genes, NPAS3, ARHGAP15, LGALS3BP, DPP10, SMYD3, CPXCR1, and HLA-DRB5 were associated with known risk factors for schizophrenia. Collectively, we identified molecular determinants of loneliness and dysregulated pathways in the brain of non-demented adults. The association of switch genes with known risk factors for neuropsychiatric and neurodegenerative diseases provides a molecular explanation for the observed prevalence of these diseases among lonely individuals.

Study on the Mechanism of Acori Graminei Rhizoma in the Treatment of Alzheimer's Disease Based on Network Pharmacology and Molecular Docking

Alzheimer's disease is a common neurodegenerative disease in the elderly. This study explored the curative effect and possible mechanism of Acori graminei rhizoma on Alzheimer's disease. In this paper, 8 active components of Acori graminei rhizoma were collected by consulting literature and using the TCMSP database, and 272 targets were screened using the PubChem and Swiss Target Prediction databases. Introduce it into the software of Cytoscape 3.7.2 and establish the graph of "drug-active ingredient-ingredient target." A total of 276 AD targets were obtained from OMIM, Gene Cards, and DisGeNET databases. Import the intersection targets of drugs and diseases into STRING database for enrichment analysis, and build PPI network in the Cytoscape 3.7.2 software, whose core targets involve APP, AMPK, NOS3, etc. GO analysis and KEGG analysis showed that there were 195 GO items and 30 AD-related pathways, including Alzheimer's disease pathway, serotonin synapse, estrogen signaling pathway, dopaminergic synapse, and PI3K-Akt signaling pathway. Finally, molecular docking was carried out to verify the binding ability between Acori graminei rhizoma and core genes. Our results predict that Acori graminei rhizoma can treat AD mainly by mediating Alzheimer's signal pathway, thus reducing the production of Aβ, inhibiting the hyperphosphorylation of tau protein, regulating neurotrophic factors, and regulating the activity of kinase to change the function of the receptor.

Novel Galectin-3 Roles in Neurogenesis, Inflammation and Neurological Diseases

Galectin-3 (Gal-3) is an evolutionarily conserved and multifunctional protein that drives inflammation in disease. Gal-3's role in the central nervous system has been less studied than in the immune system. However, recent studies show it exacerbates Alzheimer's disease and is upregulated in a large variety of brain injuries, while loss of Gal-3 function can diminish symptoms of neurodegenerative diseases such as Alzheimer's. Several novel molecular pathways for Gal-3 were recently uncovered. It is a natural ligand for TREM2 (triggering receptor expressed on myeloid cells), TLR4 (Toll-like receptor 4), and IR (insulin receptor). Gal-3 regulates a number of pathways including stimulation of bone morphogenetic protein (BMP) signaling and modulating Wnt signalling in a context-dependent manner. Gal-3 typically acts in pathology but is now known to affect subventricular zone (SVZ) neurogenesis and gliogenesis in the healthy brain. Despite its myriad interactors, Gal-3 has surprisingly specific and important functions in regulating SVZ neurogenesis in disease. Gal-1, a similar lectin often co-expressed with Gal-3, also has profound effects on brain pathology and adult neurogenesis. Remarkably, Gal-3's carbohydrate recognition domain bears structural similarity to the SARS-CoV-2 virus spike protein necessary for cell entry. Gal-3 can be targeted pharmacologically and is a valid target for several diseases involving brain inflammation. The wealth of molecular pathways now known further suggest its modulation could be therapeutically useful.

Alzheimer's disease: Is there a role for galectins?

Alzheimer's disease (AD) is the world's leading cause of neurological dysfunction, cognitive decline, and neuronal loss in the elderly. The sedimentation of beta amyloid (Aβ)-containing plaque, and formation of tau-containing neurofibrillary tangles (NFTs) along with extensive neuroinflammation, are the events that characterize the pathogenesis of AD. Galectins (gal) are carbohydrate-containing-ligand molecules recognized as potential modulators of the brain microglia polarization, immunosurveillance, neuroinflammation, and neuroprotection. Galectins 1, 3, 4, 8, and 9 are amongst the 15 members of the galectin family which are expressed in the brain. These galectins possess a significant correlation with neuromodulation through the glial cell-induced cytokine production that plays either a complementary or antagonistic role in the disturbance of the CNS physiology. Therefore, elaborating the hypothesis of galectins in the development of AD is of potential interest. This review aims at discussing the interaction between galectins and the neuropathophysiology of AD. An understanding about how galectins communicate with AD progression could lead to the development of improved diagnostic and therapeutic strategies for this leading cause of dementia worldwide.

Extracellular protein components of amyloid plaques and their roles in Alzheimer's disease pathology

Alzheimer's disease (AD) is pathologically defined by the presence of fibrillar amyloid β (Aβ) peptide in extracellular senile plaques and tau filaments in intracellular neurofibrillary tangles. Extensive research has focused on understanding the assembly mechanisms and neurotoxic effects of Aβ during the last decades but still we only have a brief understanding of the disease associated biological processes. This review highlights the many other constituents that, beside Aβ, are accumulated in the plaques, with the focus on extracellular proteins. All living organisms rely on a delicate network of protein functionality. Deposition of significant amounts of certain proteins in insoluble inclusions will unquestionably lead to disturbances in the network, which may contribute to AD and copathology. This paper provide a comprehensive overview of extracellular proteins that have been shown to interact with Aβ and a discussion of their potential roles in AD pathology. Methods that can expand the knowledge about how the proteins are incorporated in plaques are described. Top-down methods to analyze post-mortem tissue and bottom-up approaches with the potential to provide molecular insights on the organization of plaque-like particles are compared. Finally, a network analysis of Aβ-interacting partners with enriched functional and structural key words is presented.

The Protection of Lactic Acid Bacteria Fermented-Mango Peel against Neuronal Damage Induced by Amyloid-Beta

Mango peels are usually discarded as waste; however, they contain phytochemicals and could provide functional properties to food and promote human health. This study aimed to determine the optimal lactic acid bacteria for fermentation of mango peel and evaluate the effect of mango peel on neuronal protection in Neuron-2A cells against amyloid beta (Aβ) treatment (50 μM). Mango peel can be fermented by different lactic acid bacteria species. Lactobacillus acidophilus (BCRC14079)-fermented mango peel produced the highest concentration of lactic acid bacteria (exceeding 10⁸ CFU/mL). Mango peel and fermented mango peel extracts upregulated brain-derived neurotrophic factor (BDNF) expression for 1.74-fold in Neuron-2A cells. Furthermore, mango peel fermented products attenuated oxidative stress in Aβ-treated neural cells by 27%. Extracts of L. acidophilus (BCRC14079)-fermented mango peel treatment decreased Aβ accumulation and attenuated the increase of subG1 caused by Aβ induction in Neuron-2A cells. In conclusion, L. acidophilus (BCRC14079)-fermented mango peel acts as a novel neuronal protective product by inhibiting oxidative stress and increasing BDNF expression in neural cells.

Mutant Presenilin 1 Dysregulates Exosomal Proteome Cargo Produced by Human-Induced Pluripotent Stem Cell Neurons

The accumulation and propagation of hyperphosphorylated tau (p-Tau) is a neuropathological hallmark occurring with neurodegeneration of Alzheimer's disease (AD). Extracellular vesicles, exosomes, have been shown to initiate tau propagation in the brain. Notably, exosomes from human-induced pluripotent stem cell (iPSC) neurons expressing the AD familial A246E mutant form of presenilin 1 (mPS1) are capable of inducing tau deposits in the mouse brain after in vivo injection. To gain insights into the exosome proteome cargo that participates in propagating tau pathology, this study conducted proteomic analysis of exosomes produced by human iPSC neurons expressing A246E mPS1. Significantly, mPS1 altered the profile of exosome cargo proteins to result in (1) proteins present only in mPS1 exosomes and not in controls, (2) the absence of proteins in the mPS1 exosomes which were present only in controls, and (3) shared proteins which were upregulated or downregulated in the mPS1 exosomes compared to controls. These results show that mPS1 dysregulates the proteome cargo of exosomes to result in the acquisition of proteins involved in the extracellular matrix and protease functions, deletion of proteins involved in RNA and protein translation systems along with proteasome and related functions, combined with the upregulation and downregulation of shared proteins, including the upregulation of amyloid precursor protein. Notably, mPS1 neuron-derived exosomes displayed altered profiles of protein phosphatases and kinases involved in regulating the status of p-tau. The dysregulation of exosome cargo proteins by mPS1 may be associated with the ability of mPS1 neuron-derived exosomes to propagate tau pathology.

LGALS3BP/Gal-3 promotes osteogenic differentiation of human periodontal ligament stem cells

OBJECTIVE

To identify the role of LGALS3BP/Gal-3 in the process of human periodontal ligament stem cells (hPDLSCs) differentiating into osteoblasts.

METHODS

IP-WB experiments were carried out to examine the binding of LGALS3BP and Gal-3. Western blot was performed to detect the expressions of LGALS3BP and Gal-3 in hPDLSCs with or without osteogenic differentiation inducement. The expressions of differentiation-related Oct4, Sox2 and Runx2 were also detected by western blot. Alkaline Phosphatase (ALP) Assay Kit was used to measure ALP activity in hPDLSCs. The mineralization ability of hPDLSCs was observed by staining with Alizarin Red S solution.

RESULTS

LGALS3BP bound with Gal-3 in hPDLSCs, and the expression of LGALS3BP and Gal-3 was improved after osteogenic differentiation of hPDLSCs. Recombinant GAL-3 promoted the expression of differentiation-related proteins Oct4 and Sox2 and Runx2 in osteogenic differentiation-induced hPDLSCs. Recombinant GAL-3 also promoted the differentiation of osteogenesis-induced hPDLSCs. Furthermore, LGALS3BP had a facilitating effect on differentiation-related protein expression, while it could be reversed by shGal-3. LGALS3BP also promoted osteogenic capacity of hPDLSCs, and shGal-3 could reverse this effect.

CONCLUSION

LGALS3BP binds to Gal-3, producing a promoting effect on the osteogenic differentiation of human periodontal ligament stem cells.

Galectin-3 in T cell-mediated immunopathology and autoimmunity

Galectin-3 (Gal-3) is the only member of galectin family able to form pentamers and heterodimers with chemokines. Its presence in various cells and tissues suggests variety of regulatory functions in physiological conditions, but increasing body of evidence indicates involvement of Gal-3 in pathological cascades of many diseases. Gal-3 exerts different, sometimes opposite, effects in various disorders or in different phases of the same disease. These differences in action of Gal-3 are related to the localization of Gal-3 in the cell, types of receptors through which it acts, or the types of cells that secrete it. As a regulator of immune response and T-cell activity, Gal-3 appears to have important role in development of autoimmunity mediated by T cells. Absence of Gal-3 in C57Bl6 mice favors Th2 mediated inflammatory myocarditis but attenuate fibrosis. Recent data also indicate Gal-3 involvement in development atherosclerosis. In pathogenesis of diabetes type 1 and autoimmune components of diabetes type 2 Gal-3 may have detrimental or protective role depending on its intracellular or extracellular localization. Gal-3 mediates autoimmune hepatic damage through activation of T-cells or natural killer T cells. Gal-3 is an important mediator in neurodevelopment, neuropathology and behavior due to its expression both in neurons and glial cells. All together, assessing the role of Gal-3 in immunopathology and autoimmunity it could be concluded that it is an important participant in pathogenesis, as well as promising monitoring marker and therapeutic target.

Novel DNA methylation marker discovery by assumption-free genome-wide association analysis of cognitive function in twins

Privileged by rapid increase in available epigenomic data, epigenome-wide association studies (EWAS) are to make a profound contribution to understand the molecular mechanism of DNA methylation in cognitive aging. Current statistical methods used in EWAS are dominated by models based on multiple assumptions, for example, linear relationship between molecular profiles and phenotype, normal distribution for the methylation data and phenotype. In this study, we applied an assumption-free method, the generalized correlation coefficient (GCC), and compare it to linear models, namely the linear mixed model and kinship model. We use DNA methylation associated with a cognitive score in 400 and 206 twins as discovery and replication samples respectively. DNA methylation associated with cognitive function using GCC, linear mixed model, and kinship model, identified 65 CpGs (p < 1e-04) from discovery sample displaying both nonlinear and linear correlations. Replication analysis successfully replicated 9 of these top CpGs. When combining results of GCC and linear models to cover diverse patterns of relationships, we identified genes like KLHDC4, PAPSS2, and MRPS18B as well as pathways including focal adhesion, axon guidance, and some neurological signaling. Genomic region-based analysis found 15 methylated regions harboring 11 genes, with three verified in gene expression analysis, also the 11 genes were related to top functional clusters including neurohypophyseal hormone and maternal aggressive behaviors. The GCC approach detects valuable methylation sites missed by traditional linear models. A combination of methylation markers from GCC and linear models enriched biological pathways sensible in neurological function that could implicate cognitive performance and cognitive aging.

Neuroprotective Effects of 2-Substituted 1, 3-Selenazole Amide Derivatives on Amyloid-Beta-Induced Toxicity in a Transgenic Caenorhabditis Elegans Model of Alzheimer's Disease

Alzheimer's disease is an age-related neurodegenerative disease, associated with the presence of extracellular amyloid-β (Aβ) plaques and neurofibrillary tangles. Although the pathogenesis of AD remains unclear, the characteristic feature of AD was reported to be the buildup of Aβ plaques. In this study, we extensively investigated the neuroprotective effects of 2-substituted 1,3-selenazole amide derivatives (CHF11) on Aβ1-42 transgenic Caenorhabditis elegans CL4176. Results showed that worms fed with CHF11 exhibited remarkably reduced paralysis, decreased levels of toxic Aβ oligomers and Aβ plaque deposition, as well as less ROS production in comparison with the untreated worms. The effective concentrations of CHF11 were arranged in the descending order of 100 µM > 10 µM > 1 µM. Real-time PCR analysis showed that there was no significant difference in Aβ expression between CHF11-administered group and the blank control group, suggesting that CHF11-induced reduction in toxic protein deposition may be regulated at the post-transcriptional level. In the meantime, the gene expressions of hsf-1 and its downstream target hsp-12.6 were significantly increased, indicating that CHF11 against Aβ toxicity may involve in HSF-1 signaling pathway in worms. In conclusion, CHF11 exhibits a significant protective effect against β-amyloid-induced toxicity in CL4176 by reducing β-amyloid aggregation and ROS production, which may involve in HSF-1 and downstream target HSP-12.6 pathway.

Neurodegenerative Implications of Neuronal Cytoplasmic Protein Dysfunction in Response to Environmental Contaminants

Neurodegenerative diseases account for a significant portion of public health concerns particularly in the aging population. The dysfunction of interfilament proteins has been identified as a key event in the initiation of neurodegeneration and subsequent progression to neurodegenerative diseases. In addition, several studies have found associations between the dysfunction of interfilament proteins and exposure to environmental contaminants. Therefore, in this review, the role of interfilament proteins in neuronal cells, their connection to neurotoxicity from environmental contaminants, and finally the resulting neurodegeneration are discussed.

Extracellular vesicles from human iPSC-derived neural stem cells: miRNA and protein signatures, and anti-inflammatory and neurogenic properties

Grafting of neural stem cells (NSCs) derived from human induced pluripotent stem cells (hiPSCs) has shown promise for brain repair after injury or disease, but safety issues have hindered their clinical application. Employing nano-sized extracellular vesicles (EVs) derived from hiPSC-NSCs appears to be a safer alternative because they likely have similar neuroreparative properties as NSCs and are amenable for non-invasive administration as an autologous or allogeneic off-the-shelf product. However, reliable methods for isolation, characterization and testing the biological properties of EVs are critically needed for translation. We investigated signatures of miRNAs and proteins and the biological activity of EVs, isolated from hiPSC-NSCs through a combination of anion-exchange chromatography (AEC) and size-exclusion chromatography (SEC). AEC and SEC facilitated the isolation of EVs with intact ultrastructure and expressing CD9, CD63, CD81, ALIX and TSG 101. Small RNA sequencing, proteomic analysis, pathway analysis and validation of select miRNAs and proteins revealed that EVs were enriched with miRNAs and proteins involved in neuroprotective, anti-apoptotic, antioxidant, anti-inflammatory, blood-brain barrier repairing, neurogenic and Aβ reducing activities. Besides, EVs comprised miRNAs and/or proteins capable of promoting synaptogenesis, synaptic plasticity and better cognitive function. Investigations using an in vitro macrophage assay and a mouse model of status epilepticus confirmed the anti-inflammatory activity of EVs. Furthermore, the intranasal administration of EVs resulted in the incorporation of EVs by neurons, microglia and astrocytes in virtually all adult rat and mouse brain regions, and enhancement of hippocampal neurogenesis. Thus, biologically active EVs containing miRNAs and proteins relevant to brain repair could be isolated from hiPSC-NSC cultures, making them a suitable biologic for treating neurodegenerative disorders.

Identification of a novel BACE1 inhibitor, timosaponin A-III, for treatment of Alzheimer's disease by a cell extraction and chemogenomics target knowledgebase-guided method

BACKGROUND

Rhizoma Anemarrhenae (RA) has been conventionally used for treatment of Alzheimer's disease (AD) in Traditional Chinese Medicine, and thus, the active components from RA can be screened.

PURPOSE

This research aimed to identify the active components of RA and their targets and further clarify the molecular mechanisms underlying its anti-AD activity.

METHODS

First, the potential active compounds from RA were screened by neurocyte extraction and micro-dialysis methods. Second, the potential targets were predicted by a chemogenomics target knowledgebase and further explored by surface plasmon resonance and enzyme activity assays. Third, the pharmacological effects were evaluated by employing APP/PS1 transgenic mice and SH-SY5Y-APP cells. ELISAs and Western blot analyses were used to evaluate the expression of key molecules in the amyloidogenic and NMDAR/ERK pathways.

RESULTS

Timosaponin A-III (TA-III) was screened and identified as a potential active component for the anti-AD activity, and BACE1 was proven to be a potential high-affinity target. Enzyme kinetic analysis showed that TA-III had strong noncompetitive inhibitory activity against BACE1. The in vitro and in vivo assays indicated that TA-III had pharmacological effects through improving memory impairment, reducing Aβ aggregation via the amyloidogenic pathway and preventing neuronal impairment through downregulating the NMDAR/ERK signaling pathway.

CONCLUSION

TA-III targets BACE1 to reduce Aβ aggregation through down-regulating the NMDAR/ERK pathway for treating AD.

Sodium Butyrate Protects N2a Cells against Aβ Toxicity In Vitro

Alzheimer's disease (AD) is a common neurodegenerative disease. Aβ plays an important role in the pathogenesis of AD. Sodium butyrate (NaB) is a short-chain fatty acid salt that exerts neuroprotective effects such as anti-inflammatory, antioxidant, antiapoptotic, and cognitive improvement in central nervous system diseases. The aim of this study is to research the protective effects of NaB on neurons against Aβ toxicity and to uncover the underlying mechanisms. The results showed that 2 mM NaB had a significant improvement effect on Aβ-induced N2a cell injury, by increasing cell viability and reducing ROS to reduce injury. In addition, by acting on the GPR109A receptor, NaB regulates the expression of AD-related genes such as APP, NEP, and BDNF. Therefore, NaB protects N2a cells from Aβ-induced cell damage through activating GPR109A, which provides an innovative idea for the treatment of AD.