The cellular model for Alzheimer's disease research: PC12 cells

Vascular models of Alzheimer's disease: An overview of recent in vitro models of the blood-brain barrier

Alzheimer's disease (AD) remains an overwhelming epidemiologic and economic burden on our healthcare systems, affecting an estimate of 11 % of individuals aged 65 years and older. Increasing evidence of the role of the blood-brain barrier (BBB) in AD pathology lends support to the vascular hypothesis of AD, which posits that damage to cerebral vasculature and impairments to cerebral blood flow are major contributors to neurodegeneration in AD. While the question remains whether the dysfunction of the BBB is the cause or consequence of the disease, understanding of the relationship between vascular pathology and AD is growing increasingly complex, warranting the need for better tools to study vasculature in AD. This review provides an overview of AD models in the context of studying vascular impairments and their relevance in pathology. Specifically, we summarize opportunities in in vitro models, cell sources, and phenotypic observations in sporadic and familial forms of AD. Further, we describe recent advances in generating models which recapitulate in vivo characteristics of the BBB in AD through the use of microfluidics, induced pluripotent stem cells (iPSC), and organoid technologies. Finally, we provide a searchable database of reported cell-based models of pathogenic AD gene variants.

Pea Peptide Modulates Abnormal Aβ Production in PC12 Cells Induced by Lead Exposure

Lead (Pb) exposure poses significant health risks, particularly in neurodegenerative diseases such as Alzheimer's disease (AD). This study investigates the neuroprotective effects of pea peptide (PP4) on PC12 cells exposed to Pb. Using Cell Counting Kit-8 (CCK-8), pretreatment with PP4 at 50 and 200 µM concentrations significantly improved cell viability compared to Pb-only treated cells (P < 0.05), indicating a protective effect. Moreover, Pb exposure led to increased Amyloid Precursor Protein (APP) expression at 10 and 20 µM after 24 h (P < 0.05), while β-site amyloid Precursor Protein Cleaving Enzyme 1 (BACE1) levels were elevated across all concentrations tested (P < 0.05). We established that PP4 can mitigate Pb-induced cytotoxicity and reduce the expression of APP and BACE1 by activating the Phosphoinositide 3-kinase / Protein Kinase (PI3K/AKT) signaling pathway. This study highlights the potential of PP4 as a therapeutic agent in preventing neurotoxic damage associated with lead exposure, suggesting a novel approach for the management of AD.

Inhibition and Degradation of Amyloid Beta Fibrils by Peptide Inhibitors

Abnormal amyloid beta (Aβ) aggregation in the form of plaques and its deposition across the human nerve cells are a major hallmark of Alzheimer's disease. Aβ aggregation dynamics and, more importantly, various drugs' effects, either to inhibit the fibril aggregation or to degrade the mature fibrils, have been an area of active research. Large molecule (peptide-based) inhibitors, such as decapeptide (RYYAAFFARR) and pentapeptide (LPFFD), show inhibition/degradation effects on amyloid beta fibrils. Herein, a mathematical model has been proposed. The model simulates Aβ aggregation and inhibitory/degradative action of peptide inhibitors on Aβ fibrillation. Model parameters are tuned by curve fitting the experimental data. The tuned model is used to predict experimental data at different initial dose/fibril concentrations. Model predicted results are observed to be in good agreement with the reported experimental data, demonstrating model's applicability at the molecular level. Sensitivity analyses of the model parameters on the fibril concentration further establish the robustness of the proposed model.

Cordycepin mediates neuroprotection against apoptosis via ERK/CREB signaling activation in Aβ1-42-induced neuronal cell models

The aggregation of β-amyloid (Aβ) peptides has been associated with the onset of Alzheimer's disease (AD) by causing neurotoxicity due to oxidative stress and apoptosis. Cordycepin is a natural derivative of the nucleoside adenosine that displays potent antioxidant, antitumor, anti-inflammatory, and neuroprotective properties. However, the mechanism of the neuroprotective effect of cordycepin toward Aβ-induced neurotoxicity, as well as underlying mechanisms, is still unclear. In this study, we found that cordycepin conferred neuroprotection to catecholaminergic PC12 neuronal cell cultures exposed to Aβ1-42-insult by reducing the production of reactive oxygen species, restoring the mitochondrial membrane potential, and inhibiting apoptosis. Cordycepin stimulated the phosphorylation of extracellular signal-regulated kinase (ERK) and cyclic AMP-responsive element-binding protein (CREB) in a time- and concentration-dependent manner. Inhibition of the ERK pathway reduced the neuroprotective effect of cordycepin. Similar results were obtained with hippocampal HT22 neuronal cell cultures. Cumulatively, these findings suggest that cordycepin-induced neuroprotection toward Aβ1-42 neurotoxic insult may involve activation of the ERK/CREB pathway. This study expands our knowledge of the neuroprotective function of cordycepin and suggests that it holds promise as a natural lead compound for drug development in AD.

In-Depth Investigation on Potential Mechanism of Forest-Grown Ginseng Alleviating Alzheimer's Disease via UHPLC-MS-Based Metabolomics

BACKGROUND

Alzheimer's disease is a central nervous system degenerative disease closely related to age with a complex pathogenesis. As a natural medicinal plant, forest-grown ginseng (GSF) contains abundant ginsenosides and offers significant neuroprotective effects.

METHODS

In this study, we comprehensively investigated the effect of GSF on the cell viability of PC12 cells in an AD model alongside metabolic changes in the serum and brains of mice, combined with an efficacy evaluation of PC12 cells in vitro and UHPLC-MS-based metabolomics in vivo. The goal of this study is to clarify the potential mechanism of GSF in treating AD.

RESULTS

The PC12 cell results showed that GSF can promote the proliferation of PC12 cells, reduce the content of IL-8, increase the activity of SOD, and alleviate the inflammation and oxidative stress induced by Aβ25~35. The immunohistochemical results for the mouse brain tissue also showed that GSF could reduce the inflammatory response of mouse brain tissue by reducing the overexpression of IBa1. AD was alleviated by reducing Aβ protein deposition in the mouse brain tissue. An untargeted metabolomics analysis was performed using UHPLC-Q-Exactive MS and principal component analysis (PCA) to identify the differentially expressed metabolites in the serum and brain tissue of AD mice after treatment. Twenty and seventeen different metabolites were identified in the serum and brain tissue, respectively. The pathway enrichment analysis of differential metabolites showed that GSF could treat AD by up-regulating succinic acid semialdehyde, carbamoyl phosphate, Sphingosine 1-phosphate, L-cystathionine, 2-ketobutyric acid, Vanillylmandelic acid, and D-Ribose to regulate sphingomyelin metabolism, the synthesis and metabolism of neurotransmitters and precursors, and energy metabolism.

CONCLUSIONS

GSF can reduce neuroinflammation and alleviate Alzheimer's disease by regulating the metabolic disorders of amino acids, sphingolipids, unsaturated fatty acids, and arachidonic acid in mice serum and brain tissue metabolites. These results suggest a link between metabolite imbalance and AD, and reveal the basis for the mechanism of ginsenosides in AD treatment.

Simultaneous Imaging of pH and Peroxynitrite in the Endoplasmic Reticulum and Mitochondria: Revealing Organelle Interactions in Alzheimer's Disease Pathogenesis

pH and peroxynitrite (ONOO-) are two critical biomarkers to unveil the corresponding status of endoplasmic reticulum (ER) stress and mitochondrial dysfunction, which are closely related to Alzheimer's disease (AD). Simultaneously monitoring pH and ONOO- fluctuations in the ER and mitochondria during AD progression is pivotal for clarifying the interplay between the disorders of the two organelles and revealing AD pathogenesis. Herein, we designed and synthesized a dual-channel fluorescent probe (DCFP) to visualize pH and ONOO- in the ER and mitochondria. DCFP possessed excellent sensitivity and selectivity to pH and ONOO- without spectral crosstalk and was utilized in monitoring the two analytes within AD model cells and larval zebrafish. Importantly, DCFP could preferentially target mitochondria in normal cells and be enriched in the ER after mitochondrial depolarization. With the aid of DCFP, the slower acidification rate of the ER than that of mitochondria induced by Aβ oligomers (AβOs) was first identified, which could be ascribed to the relief of the AβOs-triggered ER stress through the Ca2+ migration from the ER to mitochondria. Moreover, continuous exposure to AβOs led to mitochondrial Ca2+ overload, accelerating the acidification and ONOO- overproduction within mitochondria. As a result, intracellular oxidative stress levels were elevated, further exacerbating ER stress and aggravating ER acidification in turn. The advanced understanding of the potential interplay between the ER and mitochondria in this work may offer new insights and methodologies for studying AD pathogenesis. The DCFP developed in this work could also be employed to study other diseases related to ER stress and mitochondrial dysfunction.

Bioinformatics and Deep Learning Approach to Discover Food-Derived Active Ingredients for Alzheimer's Disease Therapy

Alzheimer's disease (AD) prevention is a critical challenge for aging societies, necessitating the exploration of food ingredients and whole foods as potential therapeutic agents. This study aimed to identify natural compounds (NCs) with therapeutic potential in AD using an innovative bioinformatics-integrated deep neural analysis approach, combining computational predictions with molecular docking and in vitro experiments for comprehensive evaluation. We employed the bioinformatics-integrated deep neural analysis of NCs for Disease Discovery (BioDeepNat) application in the data collected from chemical databases. Random forest regression models were utilized to predict the IC50 (pIC50) values of ligands interacting with AD-related target proteins, including acetylcholinesterase (AChE), amyloid precursor protein (APP), beta-secretase 1 (BACE1), microtubule-associated protein tau (MAPT), presenilin-1 (PSEN1), tumor necrosis factor (TNF)-α, and valosin-containing protein (VCP). Their activities were then validated through a molecular docking analysis using Autodock Vina. Predictions by the deep neural analysis identified 166 NCs with potential effects on AD across seven proteins, demonstrating outstanding recall performance. The top five food sources of these predicted compounds were black walnut, safflower, ginger, fig, corn, and pepper. Statistical clustering methodologies segregated the NCs into six well-defined groups, each characterized by convergent structural and chemical signatures. The systematic examination of structure-activity relationships uncovered differential molecular patterns among clusters, illuminating the sophisticated correlation between molecular properties and biological activity. Notably, NCs with high activity, such as astragalin, dihydromyricetin, and coumarin, and medium activity, such as luteolin, showed promising effects in improving cell survival and reducing lipid peroxidation and TNF-α expression levels in PC12 cells treated with lipopolysaccharide. In conclusion, our findings demonstrate the efficacy of combining bioinformatics with deep neural networks to expedite the discovery of previously unidentified food-derived active ingredients (NCs) for AD intervention.

PKR Inhibitor C16 Regulates HIV-gp120 Induced Neuronal Injury and Cognitive Impairment in Vivo and in Vitro Models

To study the neuronal protective effect and its potential mechanism of C16 against gp120-induced cognitive impairment in vitro and in vivo. The NORT method was used to evaluate the short-term memory abilities of rats, the morphological changes in hippocampus were observed by Nissl staining. Cell viability and damage degree were detected by MTT and LDH. The cell living/apoptosis status of PC12 cells was determined by AO/EB double staining and the relative mRNA expressions of PKR, IRE1α, JNK, GRP78, and CHOP were detected by RT-qPCR. In comparison with the gp120 + Memantine and gp120 + C16 groups, the rats in the gp120 group showed a significantly decreased discrimination index (P < 0.001), with disordered CA1 region cells and reduced neuron numbers. AO/EB double staining revealed morphological changes in the gp120 and NMDA groups, while cells in the gp120 + C16 and NMDA + C16 groups resembled the control group. And C16 can significantly down-regulate the mRNA expression levels of PKR, IRE1α, JNK, GRP78, and CHOP. (P < 0.05). C16 can reduce the cognitive impairment stimulated by gp120 or NMDA, the protective mechanism may be correlated with inhibiting the upregulation of PKR/IRE1α/JNK pathway and suppressing apoptosis induced by downstream proteins GRP78 and CHOP.

A Roadmap of Peptide-Based Materials in Neural Regeneration

Injuries to the nervous system lead to irreversible damage and limited functional recovery. The peripheral nervous system (PNS) can self-regenerate to some extent for short nerve gaps. In contrast, the central nervous system (CNS) has an intrinsic limitation to self-repair owing to its convoluted neural microenvironment and inhibitory response. The primary phase of CNS injury, happening within 48 h, results from external impacts like mechanical stress. Afterward, the secondary phase of the injury occurs, originating from neuronal excitotoxicity, mitochondrial dysfunction, and neuroinflammation. No golden standard to treat injured neurons exists, and conventional medicine serves only as a protective approach to alleviating the symptoms of chronic injury. Synthetic peptides provide a promising approach for neural repair, either as soluble drugs or by using their intrinsic self-assembly propensity to serve as an extracellular matrix (ECM) mimic for cell adhesion and to incorporate bioactive epitopes. In this review, an overview of nerve injury models, common in vitro models, and peptide-based therapeutics such as ECM mimics is provided. Due to the complexity of treating neuronal injuries, a multidisciplinary collaboration between biologists, physicians, and material scientists is paramount. Together, scientists with complementary expertise will be required to formulate future therapeutic approaches for clinical use.

Screening of a Fraction with Higher Amyloid β Aggregation Inhibitory Activity from a Library Containing 210 Mushroom Extracts Using a Microliter-Scale High-Throughput Screening System with Quantum Dot Imaging

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disease hallmarked by amyloid plaques and neurofibrillary tangles. Amyloid plaques are formed by the amyloid β (Aβ) aggregation, so substances that inhibit this aggregation are useful for preventing and treating AD. Mushrooms are widely used medicinal fungi with high edible and nutritional value. Mushrooms have a variety of biologically active ingredients, and studies have shown that they have certain effects in anti-bacterial, anti-oxidation, anti-inflammatory, anti-tumor, and immune regulation. Previously, we developed a microliter-scale high-throughput screening (MSHTS) system using quantum dot (QD) nanoprobes to screen Aβ aggregation inhibitors. In this study, we appraised the Aβ aggregation inhibitory activity of 210 natural mushrooms from Hokkaido (Japan) and found 11 samples with high activity. We then selected Elfvingia applanata and Fuscoporia obliqua for extraction and purification as these samples were able to suppress Aβ-induced neurocytotoxicity and were readily available in large quantities. We found that the ethyl acetate (EtOAc) extract of E. applanata has high Aβ aggregation inhibitory activity, so we performed silica gel column chromatography fractionation and found that fraction 5 (f5) of the EtOAc extract displayed the highest Aβ aggregation inhibitory activity among all mushroom samples. The half-maximal effective concentration (EC50) value was 2.30 µg/mL, higher than the EC50 of 10.7 µg/mL for rosmarinic acid, a well-known Aβ aggregation inhibitor. This inhibitory activity decreased with further purification, suggesting that some compounds act synergistically. The f5 fraction also inhibited the deposition of Aβ aggregates on the cell surface of human neuroblastoma SH-SY5Y cells. Our expectation is that f5, with additional tests, may eventually prove to be an inhibitor for the prevention of AD.

Oxidative Stress Triggers a Pivotal Peptide Linked to Alzheimer's Disease

An aberrant recapitulation of a developmental mechanism driven by a 14 mer peptide ('T14') derived from acetylcholinesterase (AChE) has been implicated in Alzheimer's disease. T14 was suggested as an upstream driver of neurodegeneration due to its ability to stimulate the production of phosphorylated tau and amyloid beta. The activation of this mechanism in adulthood is thought to be brought upon by insult to the primarily vulnerable subcortical nuclei. Here, we show that oxidative stress, induced by high glucose and confirmed by an analysis of antioxidant enzyme mRNA expression, increased the levels of T14 peptide in PC12 cells. This increase in T14 corresponded with an increase in the mRNA expression of AChE and a decrease in the cell viability. The increase in T14 could be blocked by the cyclic form of T14, NBP14, which prevented any cytotoxic effects. These observations suggest that oxidative stress can directly trigger the inappropriate activation of T14 in the adult brain through the upregulation of Ache mRNA.

Preconditioning of Mesenchymal Stem Cells Enhances the Neuroprotective Effects of Their Conditioned Medium in an Alzheimer's Disease In Vitro Model

BACKGROUND

Alzheimer's disease (AD) develops as a result of oxidative damage to neurons and chronic inflammation of microglia. These processes can be influenced by the use of a conditioned medium (CM) derived from mesenchymal stem cells (MSCs). The CM contains a wide range of factors that have neurotrophic, antioxidant, and anti-inflammatory effects. In addition, the therapeutic potential of the CM can be further enhanced by pretreating the MSCs to increase their paracrine activity. The current study aimed to investigate the neuroprotective effects of CM derived from MSCs, which were either activated by a TLR3 ligand or exposed to CoCl2, a hypoxia mimetic (pCM or hCM, respectively), in an in vitro model of AD.

METHODS

We have developed a novel in vitro model of AD that allows us to investigate the neuroprotective and anti-inflammatory effects of MSCs on induced neurodegeneration in the PC12 cell line and the activation of microglia using THP-1 cells.

RESULTS

This study demonstrates for the first time that pCM and hCM exhibit more pronounced immunosuppressive effects on proinflammatory M1 macrophages compared to CM derived from untreated MSCs (cCM). This may help prevent the development of neuroinflammation by balancing the M1 and M2 microglial phenotypes via the decreased secretion of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and increased secretion of IL-4, as well as the expression of IL-10 and TGF-β by macrophages. Moreover, a previously unknown increase in the neurotrophic properties of hCM was discovered, which led to an increase in the viability of neuron-like PC12 cells under H2O2-induced oxidative-stress conditions. These results are likely associated with an increase in the production of growth factors, including vascular endothelial growth factor (VEGF). In addition, the neuroprotective effects of CM from preconditioned MSCs are also mediated by the activation of the Nrf2/ARE pathway in PC12 cells.

CONCLUSIONS

TLR3 activation in MSCs leads to more potent immunosuppressive effects of the CM against pro-inflammatory M1 macrophages, while the use of hCM led to increased neurotrophic effects after H2O2-induced damage to neuronal cells. These results are of interest for the potential treatment of AD with CM from preactivated MSCs.

A Hydroxyquinoline Polymer with Excellent Amyloidosis Inhibition and Protein Delivery Ability to Combat Amyloid-β-Mediated Neurotoxicity

The accumulation of abnormal protein deposits known as amyloid-β (Aβ) plaques contributes to the development and progression of Alzheimer's disease. Aggregated Aβ exacerbates oxidative stress by stimulating the production of reactive oxygen species (ROS) in a detrimental feedback loop. 8-Hydroxyquinoline (8-HQ) is recognized for its ability to inhibit or reverse Aβ aggregation and reduce neurotoxicity. Here, an 8-HQ-based polymer, DHQ, was developed to combat Aβ-mediated neurotoxicity by delivering an antioxidant enzyme. DHQ efficiently delivers superoxide dismutase into targeted cells, thereby downregulating the intracellular ROS level. Additionally, the polymer effectively inhibits the fibrillization of three proteins involved in fibrosis, β-lactoglobulin (BLG), insulin, and Aβ1-40, at nanomolar concentrations. Cell culture models demonstrated that DHQ reduces ROS levels induced by Aβ1-40 aggregation, rescuing cell viability and preventing apoptosis. Intracellular delivery of SOD further enhanced the ability to maintain the ROS homeostasis. This polymer offers a multifaceted approach to treating diseases associated with amyloidosis.

Pongamol Prevents Neurotoxicity via the Activation of MAPKs/Nrf2 Signaling Pathway in H2O2-Induced Neuronal PC12 Cells and Prolongs the Lifespan of Caenorhabditis elegans

Despite tremendous advances in modern medicine, effective prevention or therapeutic strategies for age-related neurodegenerative diseases such as Alzheimer's disease (AD) remain limited. Growing evidence now suggests that oxidative stress and apoptosis are increasingly associated with AD as promising therapeutic targets. Pongamol, a flavonoid, is the main constituent of pongamia pinnata and possesses a variety of pharmacological activities such as antioxidant, anti-aging and anti-inflammatory. In the present study, we investigated the antioxidant effects and mechanisms of pongamol in H2O2-induced PC12 cells and Caenorhabditis elegans (C. elegans). Our findings revealed that pongamol reduced cellular damage and apoptosis in H2O2-induced PC12 cells. Furthermore, pongamol reduced levels of apoptosis-related proteins Bax, Cyto C, Cleaved Caspase-3, and Cleaved PARP1, and increased the level of anti-apoptotic protein Bcl-2. Pongamol also effectively attenuated the level of oxidative stress markers such as glutathione (GSH) and reactive oxygen species (ROS) in H2O2-induced PC12 cells. Additionally, pongamol possessed antioxidant activity in H2O2-induced PC12 cells through the MAPKs/Nrf2 signaling pathway. Furthermore, pongamol exerted neuroprotective and anti-aging effects in C. elegans. All together, these results suggested that pongamol has a potential neuroprotective effect through the modulation of MAPKs/Nrf2 signaling pathway.

The role of neuron-like cell lines and primary neuron cell models in unraveling the complexity of neurodegenerative diseases: a comprehensive review

Neurodegenerative diseases (NDs) are characterized by the progressive loss of neurons. As to developing effective therapeutic interventions, it is crucial to understand the underlying mechanisms of NDs. Cellular models have become invaluable tools for studying the complex pathogenesis of NDs, offering insights into disease mechanisms, determining potential therapeutic targets, and aiding in drug discovery. This review provides a comprehensive overview of various cellular models used in ND research, focusing on Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Cell lines, such as SH-SY5Y and PC12 cells, have emerged as valuable tools due to their ease of use, reproducibility, and scalability. Additionally, co-culture models, involving the growth of distinct cell types like neurons and astrocytes together, are highlighted for simulating brain interactions and microenvironment. While cell lines cannot fully replicate the complexity of the human brain, they provide a scalable method for examining important aspects of neurodegenerative diseases. Advancements in cell line technologies, including the incorporation of patient-specific genetic variants and improved co-culture models, hold promise for enhancing our understanding and expediting the development of effective treatments. Integrating multiple cellular models and advanced technologies offers the potential for significant progress in unraveling the intricacies of these debilitating diseases and improving patient outcomes.

The Adrenal Pheochromocytoma Cell Line PC12 Efficiently Promotes the Regeneration Capability of Adipose Tissue-Derived Mesenchymal Stem Cells in Myogenesis: A Particular Approach to Improving Skeletal Muscle Cell Regeneration

Background

Researchers are looking for a way to improve the myogenic differentiation of stem cells. Adipose-derived stem cells (ADSCs), known for their multipotency and regenerative capabilities, have been extensively studied for their therapeutic potential. Meanwhile, PC12 cells, derived from rat pheochromocytoma, have been found pivotal in neuroscience research, particularly as a neuronal model system. The current study investigated the effect of the PC12 adrenal pheochromocytoma cell line on the myogenic differentiation of ADSCs.

Methods

This experimental study was conducted during 2019-2022 (Ahvaz, Iran). Differentiation of ADSCs was induced by using 3 μg/mL 5-azacytidine for 24 hours. Then, the culture media was changed with Dulbecco's Modified Eagle-High Glucose (DMEM-HG) containing 5% horse serum (HS) and kept for 7 days. Different percentages of differentiated ADSCs and PC12 (100:0, 70:30, 50:50, 30:70) were cocultured for 7 days in DMEM-HG containing 5% HS. PC12 was labeled with cell tracker C7000. The real-time polymerase chain reaction and Western blotting techniques were utilized to assess gene and protein expression. All experiments were repeated three times. Data were analyzed using GraphPad Prism 8.0.2 software with a one-way analysis of variance. P<0.05 was considered statistically significant.

Results

PC12 visualization confirmed the accuracy of the co-culture process. The differentiated cells showed an aligned, multinucleated shape. The differentiated ADSCs revealed significantly elevated levels of Myh1, Myh2, and Chrn-α1 gene expression compared with undifferentiated ADSCs (P<0.0001). The ADSCs cocultured with PC12 cells showed significantly higher Myh1, Myh2, and Chrn-α1 gene expression than differentiated ADSCs (P<0.001). ADSCs cocultured with 50% PC12 revealed significantly higher MYH and nAchR protein expression than the differentiated group (P<0.01 and P<0.001).

Conclusion

Coculturing PC12 cells and ADSCs improves the efficiency of myogenic differentiation. However, the effectiveness of myogenic differentiation depends on the proportions of administered PC12 cells.

Surface-Enhanced Raman Scattering Nanosensing and Imaging in Neuroscience

Monitoring neurochemicals and imaging the molecular content of brain tissues in vitro, ex vivo, and in vivo is essential for enhancing our understanding of neurochemistry and the causes of brain disorders. This review explores the potential applications of surface-enhanced Raman scattering (SERS) nanosensors in neurosciences, where their adoption could lead to significant progress in the field. These applications encompass detecting neurotransmitters or brain disorders biomarkers in biofluids with SERS nanosensors, and imaging normal and pathological brain tissues with SERS labeling. Specific studies highlighting in vitro, ex vivo, and in vivo analysis of brain disorders using fit-for-purpose SERS nanosensors will be detailed, with an emphasis on the ability of SERS to detect clinically pertinent levels of neurochemicals. Recent advancements in designing SERS-active nanomaterials, improving experimentation in biofluids, and increasing the usage of machine learning for interpreting SERS spectra will also be discussed. Furthermore, we will address the tagging of tissues presenting pathologies with nanoparticles for SERS imaging, a burgeoning domain of neuroscience that has been demonstrated to be effective in guiding tumor removal during brain surgery. The review also explores future research applications for SERS nanosensors in neuroscience, including monitoring neurochemistry in vivo with greater penetration using surface-enhanced spatially offset Raman scattering (SESORS), near-infrared lasers, and 2-photon techniques. The article concludes by discussing the potential of SERS for investigating the effectiveness of therapies for brain disorders and for integrating conventional neurochemistry techniques with SERS sensing.

Antidepressant Effect of Enzymatic Porcine Placenta Hydrolysate in Repeated Immobilization Stress-Induced Ovariectomized Female Mice

When postmenopausal women are under stress conditions, this exacerbates mood disorders and issues with neuroimmune systems. The porcine placenta is known to relieve menopausal depression in clinical trials, but its underlying mechanisms for depression and anti-inflammatory functions remain poorly defined. The present study was designed to examine the anti-inflammatory effects of enzymatic porcine placenta hydrolysate (EPPH) on LPS-induced levels of nitric oxide (NO), prostaglandin E2 (PGE2), corticosterone (CORT), and pro-inflammatory cytokine interleukin-1 beta (IL-1β) in RAW 264.7 macrophage cells. In addition, the neurite outgrowth of PC12 cells was evaluated to examine the effects of EPPH on neurite growth. To mimic the symptoms of women with menopause-related depression, a stressed ovariectomized (OVX) female mouse model was used to evaluate the antidepressant effects of EPPH. The female mice were randomly divided into five groups: (1) the sham-operated (Sham) group, (2) the OVX + repeated stress + saline-treated (OVX + ST) group, (3) the OVX + repeated stress + estradiol (0.2 mg/kg)-treated (positive control) group, (4) the OVX + repeated stress + EPPH (300 mg/kg)-treated (300) group, and (5) the OVX + repeated stress + EPPH (1500 mg/kg)-treated (1500) group. Female mice were OVX and repeatedly immobilization-stressed for 2 weeks (2 h/day). A tail suspension test was conducted on the 13th day, followed by the forced swimming test on the 14th day to assess the antidepressant effects of EPPH. After the behavioral tests, the levels of CORT, PGE2, and IL-1β were evaluated. In addition, c-Fos expression in the paraventricular nucleus (PVN) was evaluated using immunohistochemistry. The concentrations of NO, PGE2, and IL-1β stimulated by LPS were significantly reduced via the addition of EPPH to RAW 264.7 cells. EPPH significantly promoted neurite outgrowth in PC12 cells compared to that of the controls. In the tail suspension test, the duration of immobility was reduced in mice treated with EPPH 1500 compared to the OVX + ST group. The EPPH 1500 group had significantly decreased levels of c-Fos-positive neurons in the PVN and reduced levels of CORT and IL-1β in the serum of the Sham group. These results suggested that the high dose of EPPH administration induced the antidepressant-like effect in the ovariectomized mice with repeated stress via downregulating the levels of CORT, IL-1β, and PGE2 in the serum through reducing the expression of c-Fos in the PVN regions.

Effect of Xanthohumol, a Bioactive Natural Compound from Hops, on Adenosine Pathway in Rat C6 Glioma and Human SH-SY5Y Neuroblastoma Cell Lines

Xanthohumol (Xn) is an antioxidant flavonoid mainly extracted from hops (Humulus lupulus), one of the main ingredients of beer. As with other bioactive compounds, their therapeutic potential against different diseases has been tested, one of which is Alzheimer's disease (AD). Adenosine is a neuromodulatory nucleoside that acts through four different G protein-coupled receptors: A1 and A3, which inhibit the adenylyl cyclases (AC) pathway, and A2A and A2B, which stimulate this activity, causing either a decrease or an increase, respectively, in the release of excitatory neurotransmitters such as glutamate. This adenosinergic pathway, which is altered in AD, could be involved in the excitotoxicity process. Therefore, the aim of this work is to describe the effect of Xn on the adenosinergic pathway using cell lines. For this purpose, two different cellular models, rat glioma C6 and human neuroblastoma SH-SY5Y, were exposed to a non-cytotoxic 10 µM Xn concentration. Adenosine A1 and A2A, receptor levels, and activities related to the adenosine pathway, such as adenylate cyclase, protein kinase A, and 5'-nucleotidase, were analyzed. The adenosine A1 receptor was significantly increased after Xn exposure, while no changes in A2A receptor membrane levels or AC activity were reported. Regarding 5'-nucleotidases, modulation of their activity by Xn was noted since CD73, the extracellular membrane attached to 5'-nucleotidase, was significantly decreased in the C6 cell line. In conclusion, here we describe a novel pathway in which the bioactive flavonoid Xn could have potentially beneficial effects on AD as it increases membrane A1 receptors while modulating enzymes related to the adenosine pathway in cell cultures.

Ultrastructural Changes of Neuroendocrine Pheochromocytoma Cell Line PC-12 Exposed In Vitro to Rotenone

Rotenone is a pesticide used in research for its ability to induce changes similar, in vivo and in vitro, to those observed in Parkinson's disease (PD). This includes a selective death of dopaminergic neurons in the substantia nigra. Nonetheless, the precise mechanism through which rotenone modifies structure and function of neurons remains unclear. The PC12 cells closely resemble dopamine terminal neurons. This makes it a preferred model for studying the morphology of central dopamine neurons and predicting neurotoxicity. In this paper, we investigated the effects of 0.5 µM rotenone for 24-48 h on PC12 cell viability and ultrastructure (TEM), trying to identify primary and more evident alterations that can be related to neuronal damages similar to that seen in animal PD models. Cell viability decreased after 24 h rotenone treatment, with a further decrease after 48 h. Ultrastructural changes included vacuolar degeneration, mitochondrial mild swelling, decrease in the number of neuropeptide granules, and the loss of cell-to-cell adhesion. These findings are in agreement with previous research suggesting that rotenone, by inhibiting energy production and increasing ROS generation, is responsible for significant alterations of the ultrastructure and cell death of PC12 cells. Our data confirm the link between rotenone exposure, neuronal damage, and changes in dopamine metabolism, suggesting its role in the pathogenesis of PD.

Promising Application, Efficient Production, and Genetic Basis of Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs) are a class of glycolipids that have been receiving increasing attention in recent years due to their diverse biological activities. MELs are produced by certain fungi and display a range of bioactivities, making them attractive candidates for various applications in medicine, agriculture, and biotechnology. Despite their remarkable qualities, industrial-scale production of MELs remains a challenge for fungal strains. Excellent fungal strains and fermentation processes are essential for the efficient production of MELs, so efforts have been made to improve the fermentation yield by screening high-yielding strains, optimizing fermentation conditions, and improving product purification processes. The availability of the genome sequence is pivotal for elucidating the genetic basis of fungal MEL biosynthesis. This review aims to shed light on the applications of MELs and provide insights into the genetic basis for efficient MEL production. Additionally, this review offers new perspectives on optimizing MEL production, contributing to the advancement of sustainable biosurfactant technologies.

Design, Synthesis, and Biological Evaluation of Ferulic Acid Template-Based Novel Multifunctional Ligands Targeting NLRP3 Inflammasome for the Management of Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia, which arises due to low levels of acetyl and butyrylcholines, an increase in oxidative stress, inflammation, metal dyshomeostasis, Aβ and tau aggregations. The currently available drugs for AD treatment can provide only symptomatic relief without interfering with pathological hallmarks of the disease. In our ongoing efforts to develop naturally inspired novel multifunctional molecules for AD, systematic SAR studies on EJMC-4e were caried out to improve its multifunctional properties. The rigorous medicinal efforts led to the development of 12o, which displayed a 15-fold enhancement in antioxidant properties and a 2-fold increase in the activity against AChE and BChE over EJMC-4e. Molecular docking and dynamics studies revealed the binding sites and stability of the complex of 12o with AChE and BChE. The PAMPA-BBB assay clearly demonstrated that 12o can easily cross the blood-brain barrier. Interestingly, 12o also expresses promising metal chelation activity, while EJMC-4e was found to be devoid of this property. Further, 12o inhibited metal-induced or self Aβ1-42 aggregation. Observing the neuroprotection ability of 12o against H2O2-induced oxidative stress in the PC-12 cell line is noteworthy. Furthermore, 12o also inhibited NLRP3 inflammasome activation and attenuated mitochondrial-induced ROS and MMP damage caused by LPS and ATP in HMC-3 cells. In addition, 12o is able to effectively reduce mitochondrial and cellular oxidative stress in the AD Drosophila model. Finally, 12o could reverse memory impairment in the scopolamine-induced AD mice model, as evident through in vivo and ex vivo studies. These findings suggest that this compound may act as a promising candidate for further improvement in the management of AD.

Urolithin B protects PC12 cells against glutamate-induced toxicity

BACKGROUND

The involvement of malfunctioning glutamate systems in various central nervous system (CNS) disorders is widely acknowledged. Urolithin B, known for its neuroprotective and antioxidant properties, has shown potential as a therapeutic agent for these disorders. However, little is known about its protective effects against glutamate-induced toxicity in PC12 cells. Therefore, in this study, for the first time we aimed to investigate the ability of Urolithin B to reduce the cytotoxic effects of glutamate on PC12 cells.

METHODS

Different non-toxic concentrations of urolithin B were applied to PC12 cells for 24 h before exposure to glutamate (10 mM). The cells were then analyzed for cell viability, intracellular reactive oxygen species (ROS), cell cycle arrest, apoptosis, and the expression of Bax and Bcl-2 genes.

RESULTS

The results of MTT assay showed that glutamate at a concentration of 10 mM and urolithin B at a concentration of 114 μM can reduce PC12 cell viability by 50%. However, urolithin B at non-toxic concentrations of 4 and 8 μM significantly reduced glutamate-induced cytotoxicity (p < 0.01). Interestingly, treatment with glutamate significantly enhanced the intracellular ROS levels and apoptosis rate in PC12 cells, while pre-treatment with non-toxic concentrations of urolithin B significantly reduced these cytotoxic effects. The results also showed that pre-treatment with urolithin B can decrease the Bax (p < 0.05) and increase the Bcl-2 (p < 0.01) gene expression, which was dysregulated by glutamate.

CONCLUSIONS

Taken together, urolithin B may play a protective role through reducing oxidative stress and apoptosis against glutamate-induced toxicity in PC12 cells, which merits further investigations.

Spectrum-effect relationship analysis based on HPLC-FT-ICR-MS and multivariate statistical analysis to reveal the pharmacodynamic substances of Ling-Gui-Zhu-Gan decoction on Alzheimer's disease

Alzheimer's disease (AD) threatens elderly human health and still lacks effective treatment. Our previous work showed that LGZGD possessed a neuroprotective effect on the Aβ25-35-induced neurotoxicity in differentiated PC12 cells, indicating that LGZGD may be a potential drug for treatment of AD. However, its pharmacodynamic substances which show anti-inflammatory and anti-oxidant stress activities are still unrevealed. This research aims to reveal the pharmacodynamic substances of LGZGD on Aβ25-35-induced PC12 cell model of AD based on a spectrum-effect relationship study by using HPLC-FT-ICR-MS method and multivariate statistical analysis. Firstly, the chemical composition spectra of different combinations of LGZGD were recorded by HPLC-FT-ICR MS. Subsequently, Aβ25-35-induced PC12 cell model of AD was established and pharmacodynamic experiments were conducted to evaluate their anti-inflammatory and anti-oxidant activities, respectively. Finally, the potential pharmacodynamic substances were screened out through spectrum-effect relationship study accompanied by multivariate statistical analysis including bivariate correlation analysis (BCA), grey relational analysis (GRA), principal component analysis (PCA), partial least squares regression analysis (PLSR). As a result, a total of 96 chemical consistents in different combinations of LGZGD were discovered. Among them, 7 components such as isoglabrolide, licorice saponin E2, licorice saponin N2 and licoisoflavanone were directly linked with the anti-inflammatory effects, and 14 constituents such as tumulosic acid, polyporenic acid C, dehydrotumulosic acid, dehydropachymic acid, and pachymic acid were directly correlated with the anti-oxidative stress activities. In conclusion, we combined the HPLC-FT-ICR-MS spectra with pharmacodynamic indicators to develop the spectrum-effect relationships of LGZGD for the first time, and successfully revealed its potential pharmacodynamic substances in the treatment of AD from the anti-inflammatory and antioxidant pathways in the cell model.

Comparative Study of the Protective and Neurotrophic Effects of Neuronal and Glial Progenitor Cells-Derived Conditioned Media in a Model of Glutamate Toxicity In Vitro

Cell therapy represents a promising approach to the treatment of neurological diseases, offering potential benefits not only by cell replacement but also through paracrine secretory activities. However, this approach includes a number of limiting factors, primarily related to safety. The use of conditioned stem cell media can serve as an equivalent to cell therapy while avoiding its disadvantages. The present study was a comparative investigation of the antioxidant, neuroprotective and neurotrophic effects of conditioned media obtained from neuronal and glial progenitor cells (NPC-CM and GPC-CM) on the PC12 cell line in vitro. Neuronal and glial progenitor cells were obtained from iPSCs by directed differentiation using small molecules. GPC-CM reduced apoptosis, ROS levels and increased viability, expressions of the antioxidant response genes HMOX1 and NFE2L2 in a model of glutamate-induced oxidative stress. The neurotrophic effect was evidenced by a change in the morphology of pheochromocytoma cells to a neuron-like phenotype. Moreover, neurite outgrowth, expression of GAP43, TUBB3, MAP2, SYN1 genes and increased levels of the corresponding MAP2 and TUBB3 proteins. Treatment with NPC-CM showed moderate antiapoptotic effects and improved cell viability. This study demonstrated the potential application of CM in the field of regenerative medicine.

Palmatine Protects PC12 Cells and Mice from Aβ25-35-Induced Oxidative Stress and Neuroinflammation via the Nrf2/HO-1 Pathway

Alzheimer's disease is a common degenerative disease which has a great impact on people's daily lives, but there is still a certain market gap in the drug research about it. Palmatine, one of the main components of Huangteng, the rattan stem of Fibraurea recisa Pierre (Menispermaceae), has potential in the treatment of Alzheimer's disease. The aim of this study was to evaluate the neuroprotective effect of palmatine on amyloid beta protein 25-35-induced rat pheochromocytoma cells and AD mice and to investigate its mechanism of action. CCK8 assays, ELISA, the Morris water maze assay, fluorescent probes, calcein/PI staining, immunofluorescent staining and Western blot analysis were used. The experimental results show that palmatine can increase the survival rate of Aβ25-35-induced PC12 cells and mouse hippocampal neurons, reduce apoptosis, reduce the content of TNF-α, IL-1β, IL-6, GSH, SOD, MDA and ROS, improve the learning and memory ability of AD mice, inhibit the expression of Keap-1 and Bax, and promote the expression of Nrf2, HO-1 and Bcl-2. We conclude that palmatine can ameliorate oxidative stress and neuroinflammation produced by Aβ25-35-induced PC12 cells and mice by modulating the Nrf2/HO-1 pathway. In conclusion, our results suggest that palmatine may have a potential therapeutic effect on AD and could be further investigated as a promising therapeutic agent for AD. It provides a theoretical basis for the development of related drugs.

Gut-brain axis: gut dysbiosis and psychiatric disorders in Alzheimer's and Parkinson's disease

Gut dysbiosis and psychiatric symptoms are common early manifestations of Alzheimer's disease (AD) and Parkinson's disease (PD). These diseases, characterised by progressive neuron loss and pathological protein accumulation, impose debilitating effects on patients. Recently, these pathological proteins have been linked with gut dysbiosis and psychiatric disorders. The gut-brain axis links the enteric and central nervous systems, acting as a bidirectional communication pathway to influence brain function and behavior. The relationship triad between gut dysbiosis, psychiatric disorders, and neurodegeneration has been investigated in pairs; however, evidence suggests that they are all interrelated and a deeper understanding is required to unravel the nuances of neurodegenerative diseases. Therefore, this review aims to summarise the current literature on the roles of gut dysbiosis and psychiatric disorders in pathological protein-related neurodegenerative diseases. We discussed how changes in the gut environment can influence the development of psychiatric symptoms and the progression of neurodegeneration and how these features overlap in AD and PD. Moreover, research on the interplay between gut dysbiosis, psychiatric disorders, and neurodegeneration remains in its early phase. In this review, we highlighted potential therapeutic approaches aimed at mitigating gastrointestinal problems and psychiatric disorders to alter the rate of neurodegeneration. Further research to assess the molecular mechanisms underlying AD and PD pathogenesis remains crucial for developing more effective treatments and achieving earlier diagnoses. Moreover, exploring non-invasive, early preventive measures and interventions is a relatively unexplored but important avenue of research in neurodegenerative diseases.

Moschus ameliorates glutamate-induced cellular damage by regulating autophagy and apoptosis pathway

Alzheimer's disease (AD), a neurodegenerative disorder, causes short-term memory and cognition declines. It is estimated that one in three elderly people die from AD or other dementias. Chinese herbal medicine as a potential drug for treating AD has gained growing interest from many researchers. Moschus, a rare and valuable traditional Chinese animal medicine, was originally documented in Shennong Ben Cao Jing and recognized for its properties of reviving consciousness/resuscitation. Additionally, Moschus has the efficacy of "regulation of menstruation with blood activation, relief of swelling and pain" and is used for treating unconsciousness, stroke, coma, and cerebrovascular diseases. However, it is uncertain whether Moschus has any protective effect on AD patients. We explored whether Moschus could protect glutamate (Glu)-induced PC12 cells from cellular injury and preliminarily explored their related action mechanisms. The chemical compounds of Moschus were analyzed and identified by GC-MS. The Glu-induced differentiated PC12 cell model was thought to be the common AD cellular model. The study aims to preliminarily investigate the intervention effect of Moschus on Glu-induced PC12 cell damage as well as their related action mechanisms. Cell viability, lactate dehydrogenase (LDH), mitochondrial reactive oxygen species, mitochondrial membrane potential (MMP), cell apoptosis, autophagic vacuoles, autolysosomes or autophagosomes, proteins related to apoptosis, and the proteins related to autophagy were examined and analyzed. Seventeen active compounds of the Moschus sample were identified based on GC-MS analysis. In comparison to the control group, Glu stimulation increased cell viability loss, LDH release, mitochondrial damage, loss of MMP, apoptosis rate, and the number of cells containing autophagic vacuoles, and autolysosomes or autophagosomes, while these results were decreased after the pretreatment with Moschus and 3-methyladenine (3-MA). Furthermore, Glu stimulation significantly increased cleaved caspase-3, Beclin1, and LC3II protein expression, and reduced B-cell lymphoma 2/BAX ratio and p62 protein expression, but these results were reversed after pretreatment of Moschus and 3-MA. Moschus has protective activity in Glu-induced PC12 cell injury, and the potential mechanism might involve the regulation of autophagy and apoptosis. Our study may promote research on Moschus in the field of neurodegenerative diseases, and Moschus may be considered as a potential therapeutic agent for AD.

Comprehensive Review of Nutraceuticals against Cognitive Decline Associated with Alzheimer's Disease

Nowadays, nutraceuticals are being incorporated into functional foods or used as supplements with nonpharmacological approaches in the prevention and management of several illnesses, including age-related conditions and chronic neurodegenerative diseases. Nutraceuticals are apt for preventing and treating such disorders because of their nontoxic, non-habit-forming, and efficient bioactivities for promoting neurological well-being due to their ability to influence cellular processes such as neurogenesis, synaptogenesis, synaptic transmission, neuro-inflammation, oxidative stress, cell death modulation, and neuronal survival. The capacity of nutraceuticals to modify all of these processes reveals the potential to develop food-based strategies to aid brain development and enhance brain function, prevent and ameliorate neurodegeneration, and possibly reverse the cognitive impairment observed in Alzheimer's disease, the most predominant form of dementia in the elderly. The current review summarizes the experimental evidence of the neuroprotective capacity of nutraceuticals against Alzheimer's disease, describing their mechanisms of action and the in vitro and in vivo models applied to evaluate their neuroprotective potential.

New Benzodihydrofuran Derivatives Alter the Amyloid β Peptide Aggregation: Strategies To Develop New Anti-Alzheimer Drugs

Alzheimer's disease is a neurodegenerative disorder that is the leading cause of dementia in elderly patients. Amyloid-β peptide (1-42 oligomers) has been identified as a neurotoxic factor, triggering many neuropathologic events. In this study, 15 chalcones were synthesized employing the Claisen-Schmidt condensation reaction, starting from a compound derived from fomannoxine, a natural benzodihydrofuran whose neuroprotective activity has been proven and reported, and methyl aromatic ketones with diverse patterns of halogenated substitution. As a result, chalcones were obtained, with good to excellent reaction yields from 50 to 98%. Cytotoxicity of the compounds was assessed, and their cytoprotective effect against the toxicity associated with Aβ was evaluated on PC-12 cells. Out of the 15 chalcones obtained, only the 4-bromo substituted was cytotoxic at most tested concentrations. Three synthesized chalcones showed a cytoprotective effect against Aβ toxicity (over 37%). The 2,4,5-trifluoro substituted chalcone was the most promising series since it showed a cytoprotective impact with more than 60 ± 5% of recovery of cellular viability; however, 3-fluoro substituted compound also exhibited important values of recovery (50 ± 6%). The fluorine substitution pattern was shown to be more effective for cytoprotective activity. Specifically, substitution with fluorine in the 3,5-positions turned out to be particularly effective for cytoprotection. Furthermore, fluorinated compounds inhibited the aggregation rate of Aβ, suggesting a dual effect that can be the starting point of new molecules with therapeutic potential.

Effect of molecular distillation on the anti-inflammatory activity and neurotoxicity of Asarum essential oil

Asarum essential oil (AEO) has been shown to have good pharmacological activities for the anti-inflammatory and analgesic effects, but increasing the dose may cause toxicity. Therefore, we studied the toxic and pharmacodynamic components of AEO by molecular distillation (MD). Anti-inflammatory activity was assessed using RAW264.7 cells. Neurotoxicity was assessed in PC12 cells and the overall toxicity of AEO was evaluated in the mouse acute toxicity assay. The results showed that AEO is primarily composed of safrole, methyl eugenol, and 3,5-dimethoxytoluene. After MD, three fractions were obtained and contained different proportions of volatile compounds relative to the original oil. The heavy fraction had high concentrations of safrole and methyl eugenol, while the light fraction contained high concentrations of α-pinene and β- pinene. The original oil and all three fractions exhibited anti-inflammatory effects, but the light fraction demonstrated more excellent anti-inflammatory activity than the other fractions. Asarum virgin oil and MD products are all neurotoxic. The exposure of PC12 cells to high concentrations of AEO resulted in abnormal nuclei, an increased number of apoptotic cells, increased ROS formation, and decreased SOD levels. Moreover, the results of acute toxicity tests in mice revealed that the light fractions were less toxic than virgin oils and other fractions. In summary, the data suggest that the MD technology enables the enrichment and separation of essential oil components and contributes to the selection of safe concentrations of AEO.