Neurodegenerative Diseases Research Articles

Prospects for the Use of Thymoquinone (a Component of Nigella sativa) in the Prevention and Therapy of Neuropathologies

Black cumin and its component thymoquinone (TQ) are known as drugs with a wide range of pharmacological activities: immunomodulating, anti-inflammatory, antimicrobial, antiviral, antineoplastic properties. These drugs also have neuroprotective properties in neurodegenerative diseases (Alzheimer's, Parkinson's), ischaemia, epilepsy, encephalomyelitis, traumatic brain injury. The main mechanisms of action are antioxidant activity increased expression of neuroprotective genes and proteins with decreased activity of pro-inflammatory cytokines and the NF-кB pathway, which plays a key role in neuroinflammation. A separate section is devoted to the effects of black cumin and TQ on the course of depression, a common and socially significant illness. Reduced signs of depression and increased levels of a neuroprotective factor belonging to the neutrophin family (BDNF), a characteristic marker of depression, were described in 54 depressed patients. The review discusses the prospects for prevention and therapy with these drugs in central nervous system pathology.

Mechanical force of uterine occupation enables large vesicle extrusion from proteostressed maternal neurons

Large vesicle extrusion from neurons may contribute to spreading pathogenic protein aggregates and promoting inflammatory responses, two mechanisms leading to neurodegenerative disease. Factors that regulate the extrusion of large vesicles, such as exophers produced by proteostressed C. elegans touch neurons, are poorly understood. Here, we document that mechanical force can significantly potentiate exopher extrusion from proteostressed neurons. Exopher production from the C. elegans ALMR neuron peaks at adult day 2 or 3, coinciding with the C. elegans reproductive peak. Genetic disruption of C. elegans germline, sperm, oocytes, or egg/early embryo production can strongly suppress exopher extrusion from the ALMR neurons during the peak period. Conversely, restoring egg production at the late reproductive phase through mating with males or inducing egg retention via genetic interventions that block egg-laying can strongly increase ALMR exopher production. Overall, genetic interventions that promote ALMR exopher production are associated with expanded uterus lengths and genetic interventions that suppress ALMR exopher production are associated with shorter uterus lengths. In addition to the impact of fertilized eggs, ALMR exopher production can be enhanced by filling the uterus with oocytes, dead eggs, or even fluid, supporting that distention consequences, rather than the presence of fertilized eggs, constitute the exopher-inducing stimulus. We conclude that the mechanical force of uterine occupation potentiates exopher extrusion from proximal proteostressed maternal neurons. Our observations draw attention to the potential importance of mechanical signaling in extracellular vesicle production and in aggregate spreading mechanisms, making a case for enhanced attention to mechanobiology in neurodegenerative disease.

Neurofilament light chain and Polyglutamine disease

Polyglutamine (PolyQ) disease is a group of hereditary neurodegenerative diseases. It has become clear that brain damage may occur decades before the onset of symptoms. As a sensitive marker for neuro-axonal damages, neurofilament light chain (NfL) has appeared as a promising biomarker for neurological diseases. it may be used as a preclinical and clinical marker for the neurodegeneration in polyQ diseases, and is closely correlated with disease severity and progression, in particular different disease stages. This article has provided a review for the value of NfL as a biomarker in polyQ disease and its future research directions.

PTPRJ is a negative regulator of insulin signaling in neuronal cells, impacting protein biosynthesis, and neurite outgrowth.

Central insulin resistance has been linked to the development of neurodegenerative diseases and mood disorders. Various proteins belonging to the enzyme family of protein tyrosine phosphatases (PTPs) act as inhibitors of insulin signaling. Protein tyrosine phosphatase receptor type J (PTPRJ) has been identified as a negative regulator in insulin signaling in the periphery. However, the impact of PTPRJ on insulin signaling and its functional role in neuronal cells is largely unknown. Therefore, we generated a Ptprj knockout (KO) cell model in the murine neuroblast cell line Neuro2a by CRISPR-Cas9 gene editing. Ptprj KO cells displayed enhanced insulin signaling, as shown by increased phosphorylation of the insulin receptor (INSR), IRS-1, AKT, and ERK1/2. Further, proximity ligation assays (PLA) revealed both direct interaction of PTPRJ with the INSR and recruitment of this phosphatase to the receptor upon insulin stimulation. By RNA sequencing gene expression analysis, we identified multiple gene clusters responsible for glucose uptake and metabolism, and genes involved in the synthesis of various lipids being mainly upregulated under PTPRJ deficiency. Furthermore, multiple Ca2+ transporters were differentially expressed along with decreased protein biosynthesis. This was accompanied by an increase in endoplasmic reticulum (ER) stress markers. On a functional level, PTPRJ deficiency compromised cell differentiation and neurite outgrowth, suggesting a role in nervous system development. Taken together, PTPRJ emerges as a negative regulator of central insulin signaling, impacting neuronal metabolism and neurite outgrowth.

GFAP and NfL as fluid biomarkers for clinical disease severity and disease progression in multiple system atrophy (MSA).

Multiple system atrophy (MSA), an atypical parkinsonian syndrome, is a rapidly progressive neurodegenerative disease with currently no established fluid biomarkers available. MSA is characterized by an oligodendroglial α-synucleinopathy, progressive neuronal cell loss and concomitant astrocytosis. Here, we investigate glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) as fluid biomarkers for differential diagnosis, assessment of clinical disease severity and prediction of disease progression in MSA. GFAP and NfL levels were analyzed in plasma and CSF samples of 47 MSA patients as well as 24 Parkinson's disease (PD) and 25 healthy controls (HC) as reference cohorts. In MSA, biomarker levels were correlated to baseline and longitudinal clinical disease severity (UMSARS scores). In MSA, GFAP levels in CSF and plasma predicted baseline clinical disease severity as indicated by UMSARS scores, while NfL levels predicted clinical disease progression as indicated by longitudinal changes in UMSARS scores. Cross-sectionally, NfL levels in CSF and plasma were significantly elevated in MSA compared to both PD and HC. Receiver operating curves (ROC) indicated high diagnostic accuracy of NfL for distinguishing MSA from PD (CSF: AUC = 0.97, 95% CI 0.90-1.00; plasma: AUC = 0.90, 95% CI 0.81-1.00). In MSA, GFAP shows promise as novel biomarker for assessing current clinical disease severity, while NfL might serve as biomarker for prediction of disease progression and differential diagnosis of MSA against PD.

Vanadium Carbide Quantum Dots Exert Efficient Anti‐Inflammatory Effects in Lipopolysaccharide‐Induced BV2 Microglia and Mice

The regulation of glial cell activation is a critical step for the treatment or prevention of neuroinflammation‐based brain diseases. However, the development of therapeutic drugs that pass the blood–brain barrier (BBB) and inhibit the glia cell activation remains a significant challenge. Herein, an ultrasmall 2D vanadium carbide quantum dots (V2C QDs) that are capable of crossing the BBB are prepared, and the admirable anti‐neuroinflammatory effects are presented. The prepared 2D V2C QDs with an average size of 2.54 nm show good hydrophilicity, physiological stability, and effective BBB‐crossing ability. The biological effect of V2C QDs on inflammatory reactions demonstrates fascinating results in preventing the impairment of learning and memory in BALB/c mice stimulated by lipopolysaccharide. Investigation of molecular mechanism reveals that V2C QDs not only inhibit the toll‐like receptor 4/myeloid differentiation factor 88‐mediated nuclear factor kappa B and mitogen‐activated protein kinase pathways, but also prevent eukaryotic translation initiation factor 2α/activating transcription factor 4/C/EBP homologous protein‐signaling pathway and reduce oxidative stress via activating the NF‐E2‐related factor‐2/heme oxygenase‐1‐signaling pathway, leading to greatly inhibited activation of microglia and astrocytes and weakened production of inflammatory cytokines. In summary, V2C QDs exert potent anti‐inflammatory effects through multiple pathways, thus offer great potential for the treatment of neurodegenerative diseases.

A scoping review of the role of managed entry agreements in upcoming drugs for amyotrophic lateral sclerosis: learning from the case of spinal muscular atrophy

Introduction: The therapeutic options for spinal muscular atrophy (SMA) are encouraging. However, there is currently no cure for amyotrophic lateral sclerosis (ALS). The clinical and economic uncertainty surrounding innovative treatments for rare neurodegenerative diseases makes it necessary to understand managed entry agreements (MEAs). The aim of this study was to review whether models of MEAs in SMA could be extrapolated to ALS. Methods: We performed a scoping review with information on MEAs on SMA in Web of Science (WOS), PubMed, Lyfegen Library, the National Institute for Health and Care Excellence (NICE), and the Canadian Agency for Drugs and Technologies in Health (CADTH). Results: We found 45 results in WOS and PubMed. After an initial survey, 10 were reviewed to assess eligibility, and three were selected. We obtained 44 results from Lyfegen Library, and three results each from NICE and CADTH. Conclusion: The main objective of MEAs is to reduce uncertainty in the financing of drugs with a high budgetary impact and clinical concerns, as is the case with drugs for SMA and ALS. While the information available on MEAs in SMA is scarce, some conceptual models are publicly available. MEAs for long-term treatments for SMA could be used for the design of MEAs in ALS because of their similarities in economic and clinical uncertainty.

Co-opting templated aggregation to degrade pathogenic tau assemblies and improve motor function.

Protein aggregation causes a wide range of neurodegenerative diseases. Targeting and removing aggregates, but not the functional protein, is a considerable therapeutic challenge. Here, we describe a therapeutic strategy called "RING-Bait," which employs an aggregating protein sequence combined with an E3 ubiquitin ligase. RING-Bait is recruited into aggregates, whereupon clustering dimerizes the RING domain and activates its E3 function, resulting in the degradation of the aggregate complex. We exemplify this concept by demonstrating the specific degradation of tau aggregates while sparing soluble tau. Unlike immunotherapy, RING-Bait is effective against both seeded and cell-autonomous aggregation. RING-Bait removed tau aggregates seeded from Alzheimer's disease (AD) and progressive supranuclear palsy (PSP) brain extracts and was also effective in primary neurons. We used a brain-penetrant adeno-associated virus (AAV) to treat P301S tau transgenic mice, reducing tau pathology and improving motor function. A RING-Bait strategy could be applied to other neurodegenerative proteinopathies by replacing the Bait sequence to match the target aggregate.

ECLiPSE: a versatile classification technique for structural and morphological analysis of 2D and 3D single-molecule localization microscopy data.

Single-molecule localization microscopy (SMLM) has gained widespread use for visualizing the morphology of subcellular organelles and structures with nanoscale spatial resolution. However, analysis tools for automatically quantifying and classifying SMLM images have lagged behind. Here we introduce Enhanced Classification of Localized Point clouds by Shape Extraction (ECLiPSE), an automated machine learning analysis pipeline specifically designed to classify cellular structures captured through two-dimensional or three-dimensional SMLM. ECLiPSE leverages a comprehensive set of shape descriptors, the majority of which are directly extracted from the localizations to minimize bias during the characterization of individual structures. ECLiPSE has been validated using both unsupervised and supervised classification on datasets, including various cellular structures, achieving near-perfect accuracy. We apply two-dimensional ECLiPSE to classify morphologically distinct protein aggregates relevant for neurodegenerative diseases. Additionally, we employ three-dimensional ECLiPSE to identify relevant biological differences between healthy and depolarized mitochondria. ECLiPSE will enhance the way we study cellular structures across various biological contexts.

Causal Associations Between Tea Consumption and REM Sleep Behavior Disorder: A Mendelian Randomization Study.

Previous studies have shown that tea consumption may have a protective effect against neurodegenerative diseases. However, the exact causal relationship between tea consumption and the precursor stages of certain neurodegenerative diseases, namely REM sleep behavior disorder (RBD), remains unclear. To evaluate the causal association between tea consumption and RBD, we employed a Mendelian randomization study. We identified genetic instrumental variables that are significantly associated with tea consumption through genome-wide association studies (GWAS) in European populations. Bidirectional two-sample Mendelian randomization was utilized to determine the causal relationship between tea consumption and RBD, while sensitivity analyses were further employed to evaluate the robustness of the results. The multivariate Mendelian randomization method was used to assess the influence of relevant confounding factors on the results. In the MR analysis using the inverse variance weighting method, a significant causal relationship between tea consumption and RBD was observed (OR=0.046, 95% CI 0.004-0.563, p=0.016). The consistency of findings across maximum likelihood, MR PRESSO, and multivariate MR after adjusting for potential confounding further supports this causal association. Sensitivity analyses revealed no evidence of heterogeneity or pleiotropy. The findings of our study demonstrate a robust causal association between tea consumption and RBD, indicating that tea consumption may serve as a protective factor against the development of RBD.

An efficient ranking-based ensembled multiclassifier for neurodegenerative diseases classification using deep learning.

Neurodegenerative diseases are group of debilitating and progressive disorders that primarily affect the structure and functions of nervous system, leading to gradual loss of neurons and subsequent decline in cognitive, and behavioral activities. The two frequent diseases affecting the world's significant population falling in the above category are Alzheimer's disease (AD) and Parkinson's disease (PD). These disorders substantially impact the quality of life and burden healthcare systems and society. The demographic characteristics, and machine learning approaches have now been employed to diagnose these illnesses; however, they possess accuracy limitations. Therefore, the authors have developed ranking-based ensemble approach based on the weighted strategy of deep learning classifiers. The whole modeling procedure of the proposed approach incorporates three phases. In phase I, preprocessing techniques are applied to clean the noise in datasets to make it standardized according to deep learning models as it significantly impacts their performance. In phase II, five deep learning models are selected for classification and calculation of prediction results. In phase III, a ranking-based ensemble approach is proposed to ensemble the results of the five models after calculating the ranks and weights of them. In addition, the Magnetic Resonance Imaging (MRI) datasets named Alzheimer's Disease Neuroimaging Initiative (ADNI) for AD classification and Parkinson's Progressive Marker Initiative (PPMI) for PD classification are selected to validate the proposed approach. Furthermore, the proposed method achieved the classification accuracy on AD- Cognitive Normals (CN) at 97.89%, AD- Mild Cognitive Impairment (MCI) at 99.33% and CN-MCI at 99.44% and on PD-CN at 99.22%, PD- Scans Without Evidence of Dopaminergic Effect (SWEDD) at 97.56% and CN-SWEDD at 98.22% respectively. Also, the multi-class classification shows the promising accuracy of 97.18% for AD and 97.85% for PD for the proposed framework. The findings of the study show that the proposed deep learning-based ensemble technique is competitive for AD and PD prediction in both multiclass and binary class classification. Furthermore, the proposed approach enhances generalization performance in diagnosing neurodegenerative diseases and performs better than existing approaches.

Artemisinin inhibits neuronal ferroptosis in Alzheimer's disease models by targeting KEAP1.

Ferroptosis, a form of cell death characterized by lipid peroxidation, is involved in neurodegenerative diseases such as Alzheimer´s disease (AD). Recent studies have shown that a first-line antimalarial drug artemisinin is effective to counteract AD pathology. In this study, we investigated the protective effect of artemisinin against neuronal ferroptosis and the underlying mechanisms. In hippocampal HT22 cells, pretreatment with artemisinin dose-dependently protected against Erastin-induced cell death with an EC50 value of 5.032 µM, comparable to the ferroptosis inhibitor ferrostatin-1 (EC50 = 4.39 µM). We demonstrated that artemisinin (10 μM) significantly increased the nuclear translocation of Nrf2 and upregulated SLC7A11 and GPX4 in HT22 cells. Knockdown of Nrf2, SLC7A11 or GPX4 prevented the protective action of artemisinin, indicating that its anti-ferroptosis effect is mediated by the Nrf2-SLC7A11-GPX4 pathway. Molecular docking and Co-Immunoprecipitation (Co-IP) analysis revealed that artemisinin competitively binds with KEAP1, promoting the dissociation of KEAP1-Nrf2 complex and inhibiting the ubiquitination of Nrf2. Intrahippocampal injection of imidazole-ketone-Erastin (IKE) induced ferroptosis in mice accompanied by cognitive deficits evidenced by lower preference for exploration of new objects and new object locations in the NOR and NOL tests. Artemisinin (5, 10 mg/kg, i.p.) dose-dependently inhibited IKE-induced ferroptosis in hippocampal CA1 region and ameliorated learning and memory impairments. Moreover, we demonstrated that artemisinin reversed Aβ1-42-induced ferroptosis, lipid peroxidation and glutathione depletion in HT22 cells, primary hippocampal neurons, and 3×Tg mice via the KEAP1-Nrf2 pathway. Our results demonstrate that artemisinin is a novel neuronal ferroptosis inhibitor that targets KEAP1 to activate the Nrf2-SLC7A11-GPX4 pathway.

Dynamic Brain Lipid Profiles Modulate Microglial Lipid Droplet Accumulation and Inflammation Under Ischemic Conditions in Mice.

Microglia are critically involved in post-stroke inflammation affecting neurological outcomes. Lipid droplet (LD) accumulation in microglia results in a dysfunctional and pro-inflammatory state in the aged brain and worsens the outcome of neuroinflammatory and neurodegenerative diseases. However, the role of LD-rich microglia (LDRM) under stroke conditions is unknown. Using in vitro and in vivo stroke models, herein accumulation patterns of microglial LD and their corresponding microglial inflammatory signaling cascades are studied. Interactions between temporal and spatial dynamics of lipid profiles and microglial phenotypes in different post-stroke brain regions are found. Hence, microglia display enhanced levels of LD accumulation and elevated perilipin 2 (PLIN2) expression patterns when exposed to hypoxia or stroke. Such LDRM exhibit high levels of TNF-α, IL-6, and IL-1β as well as a pro-inflammatory phenotype and differentially expressed lipid metabolism-related genes. These post-ischemic alterations result in distinct lipid profiles with spatial and temporal dynamics, especially with regard to cholesteryl ester and triacylglycerol levels, further exacerbating post-ischemic inflammation. The present study sheds new light on the dynamic changes of brain lipid profiles and aggregation patterns of LD in microglia exposed to ischemia, demonstrating a mutual mechanism between microglial phenotype and function, which contributes to progression of brain injury.

Proteomic landscape of tunneling nanotubes reveals CD9 and CD81 tetraspanins as key regulators.

Tunneling nanotubes (TNTs) are open actin- and membrane-based channels, connecting remote cells and allowing direct transfer of cellular material (e.g. vesicles, mRNAs, protein aggregates) from the cytoplasm to the cytoplasm. Although they are important especially, in pathological conditions (e.g. cancers, neurodegenerative diseases), their precise composition and their regulation were still poorly described. Here, using a biochemical approach allowing to separate TNTs from cell bodies and from extracellular vesicles and particles (EVPs), we obtained the full composition of TNTs compared to EVPs. We then focused on two major components of our proteomic data, the CD9 and CD81 tetraspanins, and further investigated their specific roles in TNT formation and function. We show that these two tetraspanins have distinct non-redundant functions: CD9 participates in stabilizing TNTs, whereas CD81 expression is required to allow the functional transfer of vesicles in the newly formed TNTs, possibly by regulating docking to or fusion with the opposing cell.

Proteomic landscape of tunneling nanotubes reveals CD9 and CD81 tetraspanins as key regulators

Tunneling nanotubes (TNTs) are open actin- and membrane-based channels, connecting remote cells and allowing direct transfer of cellular material (e.g. vesicles, mRNAs, protein aggregates) from the cytoplasm to the cytoplasm. Although they are important especially, in pathological conditions (e.g. cancers, neurodegenerative diseases), their precise composition and their regulation were still poorly described. Here, using a biochemical approach allowing to separate TNTs from cell bodies and from extracellular vesicles and particles (EVPs), we obtained the full composition of TNTs compared to EVPs. We then focused on two major components of our proteomic data, the CD9 and CD81 tetraspanins, and further investigated their specific roles in TNT formation and function. We show that these two tetraspanins have distinct non-redundant functions: CD9 participates in stabilizing TNTs, whereas CD81 expression is required to allow the functional transfer of vesicles in the newly formed TNTs, possibly by regulating docking to or fusion with the opposing cell.

Chlorella Vulgaris‐Inspired Versatile Theranostic Nanoparticles for Specific Recognition and Detoxification to Copper (II) In Vitro and In Vivo

AbstractSpecific recognition and detoxification for copper is the key step for the early diagnosis and treatment of various diseases such as neurodegenerative disease and Wilson's disease. Herein, a Chlorella vulgaris‐inspired versatile theranostic nanoparticles is facilely and greenly prepared by assembling quercetin into poly(beta‐cyclodextrin) (PQNPs), which is further employed in the specific recognition and detoxification for Cu2+ in vitro and in vivo. PQNPs can be used in the detection of Cu2+ in aqueous solutions with fast response time (<5 s) and low detection limit (6.499 nM). The detection for Cu2+ in water and serum can be achieved by naked eye instantaneously on a PQNPs‐based paper sensor, and PQNPs can also act as a biological diagnostic agent for the Cu2+ imaging. Remarkably, PQNPs significantly enhance cell viability of the cell models induced by Cu2+ through the synergistic capacities of chelating Cu2+ and antioxidation. The detoxification of PQNPs for copper poisoning model is further ascertained in vivo, and it found that poly‐β‐cyclodextrin is capable of crossing the blood–brain barrier. Taken together, the as‐prepared versatile theranostic nanoparticles possess advantages of simple composition, significant theranostic efficacy, and novel treatment pattern, presenting an intriguing avenue to develop therapeutics for tackling abnormal copper metabolism in the clinic.

The association between cumulative exposure to PM2.5 and DNA methylation measured using methyl-capture sequencing among COPD patients

BackgroundParticulate matter with a diameter of < 2.5 μm (PM2.5) influences gene regulation via DNA methylation; however, its precise mechanism of action remains unclear. Thus, this study aimed to examine the connection between personal PM2.5 exposure and DNA methylation in CpG islands as well as explore the associated gene pathways.MethodsA total of 95 male patients with chronic obstructive pulmonary disease (COPD) were enrolled in this study. PM2.5 concentrations were measured for 12 months, with individual exposure recorded for 24 h every 3 months. Mean indoor and estimated individual PM2.5 exposure levels were calculated for short-term (7 days), mid-term (35 days), and long-term (90 days). DNA methylation analysis was performed on the blood samples, which, after PCR amplification and hybridization, were finally sequenced using an Illumina NovaSeq 6000 system. Correlation between PM2.5 exposure and CpG methylation sites was confirmed via a mixed-effects model. Functional enrichment analysis was performed on unique CpG methylation sites associated with PM2.5 exposure to identify the relevant biological functions or pathways.ResultsThe number of CpG sites showing differential methylation was 36, 381, and 182 for the short-, mid-, and long-term indoor models, respectively, and 3, 98, and 28 for the short-, mid-, and long-term estimated exposure models, respectively. The representative genes were TMTC2 (p = 1.63 × 10-3, R2 = 0.656), GLRX3 (p = 1.46 × 10-3, R2 = 0.623), DCAF15 (p = 2.43 × 10-4, R2 = 0.623), CNOT6L (p = 1.46 × 10-4, R2 = 0.609), BSN (p = 2.21 × 10-5, R2 = 0.606), and SENP6 (p = 1.59 × 10-4, R2 = 0.604). Functional enrichment analysis demonstrated that the related genes were mostly associated with pathways related to synaptic transmission in neurodegenerative diseases and cancer.ConclusionA significant association was observed between PM2.5 exposure and DNA methylation upon short-term exposure, and the extent of DNA methylation was the highest upon mid-term exposure. Additionally, various pathways related to neurodegenerative diseases and cancer were associated with patients with COPD.ClinicalTrials.gov identifierNCT04878367.

Measurement of blood-brain barrier water exchange rate using diffusion-prepared and multi-echo arterial spin labelling: Comparison of quantitative values and age dependence.

Water exchange rate (Kw) across the blood-brain barrier (BBB) is an important physiological parameter that may provide new insight into ageing and neurodegenerative disease. Recently, two non-invasive arterial spin labelling (ASL) MRI methods have been developed to measure Kw, but results from the different methods have not been directly compared. Furthermore, the association of Kw with age for each method has not been investigated in a single cohort. Thirty participants (70% female, 63.8 ± 10.4years) were scanned at 3T with Diffusion-Prepared ASL (DP-ASL) and Multi-Echo ASL (ME-ASL) using previously implemented acquisition and analysis protocols. Grey matter Kw, cerebral blood flow (CBF) and arterial transit time (ATT) were extracted. CBF values were consistent; approximately 50 ml/min/100 g for both methods, and a strong positive correlation in CBF from both methods across participants (r = 0.82, p < 0.001). ATT was significantly different between methods (on average 147.7ms lower when measured with DP-ASL compared to ME-ASL) but was positively correlated across participants (r = 0.39, p < 0.05). Significantly different Kw values of 106.6±19.7min-1 and 306.8±71.7min-1 were measured using DP-ASL and ME-ASL, respectively, and DP-ASL Kw and ME-ASL Kw were negatively correlated across participants (r = -0.46, p < 0.01). Kw measured using ME-ASL had a significant linear relationship with age (p < 0.05). In conclusion, DP-ASL and ME-ASL provided estimates of Kw with significantly different quantitative values and inconsistent dependence with age. We propose future standardisation of modelling and fitting methods for DP-ASL and ME-ASL, to evaluate the effect on Kw quantification. Also, sensitivity and bias analyses should be performed for both approaches, to assess the effect of varying acquisition and fitting parameters. Lastly, comparison with independent measures of BBB water transport, and with physiological and clinical biomarkers known to be associated with changes in BBB permeability, are essential to validate the ASL methods, and to demonstrate their clinical utility.

High-Impact AMPAkines Elevate Calcium Levels in Cortical Astrocytes by Mobilizing Endoplasmic Reticular Calcium Stores

Ampakines—positive allosteric modulators of AMPA-type glutamate receptors (AMPARs)—are drug candidates that have shown substantial promise in pre-clinical models of various neurodegenerative and neuropsychiatric diseases. Much of the study of ampakines has focused on how these drugs modulate neuronal AMPARs to achieve certain therapeutic effects. However, astrocytes also express functional AMPARs and their physiology may be sensitive to modulation by ampakines. Herein, we investigate the effects of multiple ampakines on calcium levels in cortical astrocytes. We find that ampakines augment cytosolic calcium elevations in astrocytes to an extent far greater than that achieved by AMPA alone. This effect is amenable to competitive AMPAR blockade. Furthermore, calcium induction is sensitive to phospholipase Cβ antagonism and blockade of inositol triphosphate receptors located on the endoplasmic reticulum. Low-impact ampakines exerted weaker effects on cytosolic calcium levels in astrocytes and higher concentrations were required to observe an effect. Furthermore, high doses of the low-impact ampakine, CX717, were not toxic to cortical astrocytes at high concentrations, which may serve to differentiate low-impact ampakines from classical AMPAR positive modulators like cyclothiazide. As ampakines are further developed for clinical use, it would be prudent to determine the extent to and manner by which they affect astrocytes, as these effects may also underpin their therapeutic utility in CNS pathologies.

Role of Noncoding RNAs in Modulating Microglial Phenotype.

Microglia are immunocompetent cells that are present in the retina and central nervous system, and are involved in the development maintenance and immune functions in these systems. Developing from yolk sac-primitive macrophages, they proliferate in the local tissues during the embryonic period without resorting to the production from the hematopoietic stem cells, and are critical in sustaining homeostasis and performing in disease and injury; they have morphological characteristics and distinct phenotypes according to the microenvironment. Microglia are also present in close association with resident cells in the retina where they engage in synapse formation, support normal functions, as well as immune defense. They are involved in the development of numerous neurodegenerative and ophthalmic diseases and act as diversity shields and triggers. Noncoding ribonucleic acids (ncRNAs) refer to RNA molecules synthesized from the mammalian genome, and these do not have protein-coding capacity. These ncRNAs play a role in the regulation of gene expression patterns. ncRNAs have only been recently identified as vastly significant molecules that are involved in the posttranscriptional regulation. Microglia are crucial for brain health and functions and current studies have focused on the effects caused by ncRNA on microglial types. Thus, the aim of the review was to provide an overview of the current knowledge about the regulation of microglial phenotypes by ncRNAs.