Differential Expression of ABC Transporter Genes in Brain Vessels vs. Peripheral Tissues and Vessels from Human, Mouse and Rat

Analogue-Specific Transplacental Transfer of Organophosphate Flame Retardants in ICR Mouse Mediated by Active Transport

Prenatal exposure to organophosphate flame retardants (OPFRs) may pose potential health risks to offspring. While prior studies have demonstrated that OPFRs can be transferred from mothers to fetuses, the mechanism underlying transplacental transfer remains unclear. The pregnant ICR mouse and JAR cell (a monolayer model), in combination with molecular docking, were used to explore the underlying mechanism. OPFRs were rapidly metabolized into diester metabolites following oral gavage in the ICR mouse, with considerable concentrations detected in maternal serum, amniotic fluid, and placenta, as well as fetus within 3 h. After 6 h, the accumulation ratios of OPFRs between the mother and fetus exhibited a parabolic relationship with log KOW. Oral exposure resulted in a decrease in interstitial cells in the decidua and an expansion of vascular systems in the labyrinthine area. RT-qPCR analysis revealed upregulated expression levels of transporter mRNA in the placenta, suggesting a protective mechanism characterized by greater efflux than influx transport efficiency. Metabolic inhibitors applied during in vitro transepithelial transport experiments using the JAR cells significantly reduced the transport efficiency, indicating that active transport facilitated the transplacental transport of aryl-OPFRs, with reductions exceeding 50%. Molecular docking analysis indicated that aryl-OPFRs exhibited greater binding affinities to placental transporters compared to other types of OPFRs, with more bonding interactions. These findings offer new insights into the potential health impacts of OPFR exposure and highlight the importance of elucidating their transplacental transport mechanisms.

An imaging and genetic-based deep learning network for Alzheimer's disease diagnosis

Conventional computer-aided diagnostic techniques for Alzheimer's disease (AD) predominantly rely on magnetic resonance imaging (MRI) in isolation. Genetic imaging methods, by establishing the link between genes and brain structures in disease progression, facilitate early prediction of AD development. While deep learning methods based on MRI have demonstrated promising results for early AD diagnosis, the limited dataset size has led most AD studies to lean on statistical approaches within the realm of imaging genetics. Existing deep-learning approaches typically utilize pre-defined regions of interest and risk variants from known susceptibility genes, employing relatively straightforward feature fusion methods that fail to fully capture the relationship between images and genes. To address these limitations, we proposed a multi-modal deep learning classification network based on MRI and single nucleotide polymorphism (SNP) data for AD diagnosis and mild cognitive impairment (MCI) progression prediction. Our model leveraged a convolutional neural network (CNN) to extract whole-brain structural features, a Transformer network to capture genetic features, and employed a cross-transformer-based network for comprehensive feature fusion. Furthermore, we incorporated an attention-map-based interpretability method to analyze and elucidate the structural and risk variants associated with AD and their interrelationships. The proposed model was trained and evaluated using 1,541 subjects from the ADNI database. Experimental results underscored the superior performance of our model in effectively integrating and leveraging information from both modalities, thus enhancing the accuracy of AD diagnosis and prediction.

Lung proteomic and metabolomic changes induced by carbon black nanoparticles and high humidity in a mouse asthma model

Allergic asthma is a significant international concern in respiratory health, which can be exacerbated by the increasing levels of non-allergenic pollutants. This rise in airborne pollutants is a primary driver behind the growing prevalence of asthma, posing a health emergency. Additionally, climatic risk factors can contribute to the onset and progression of asthma. Understanding the complex interplay between pollution, climate, and asthma induction is crucial to elucidate how environmental changes intensify asthma. In this study, we investigated the proteomic and metabolomic changes in the lungs of a mouse asthma model following co-exposure to carbon black nanoparticles and high humidity, which represent airborne and climatic factors, respectively. An asthma model was established using ovalbumin, and mice were intratracheally instilled with 15 or 30 μg/kg of carbon black and simultaneously exposed to either 70% or 90% relative humidity. Protein and metabolite profiles from the lung were used to analyze the most significantly changed clusters, and potential biomarkers and enriched pathways were identified to dissect the adverse effects of the two risk factors. The lung proteome and metabolome are significantly altered by the co-exposure, with the effects modulated by carbon black concentration and humidity level. This study proposes 10 proteins and 18 metabolites as candidate biomarkers. The significantly enriched KEGG pathways include one protein pathway (primary immunodeficiency) and six metabolic pathways (ABC transporters, nucleotide metabolism, Parkinson's disease, purine metabolism, choline metabolism in cancer, and biosynthesis of cofactors). A joint proteomic and metabolomic analysis identifies five common pathways across both omics, namely, ABC transporters, central carbon metabolism in cancer, EGFR tyrosine kinase inhibitor resistance, glioma, and NF-kappa B signaling pathway, disturbed by the co-exposure. We provide a multi-omic basis for the health risk assessment and management of co-exposures to environmental risk factors.

The molecular mechanism of Xiaoyaosan in treating major depressive disorder: Integrated analysis of DNA methylation and RNA sequencing of the arcuate nucleus in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyaosan, a classic Chinese herbal formula, exhibits promising antidepressant effects. However, its specific antidepressant mechanisms remain incompletely understood. Previous studies have highlighted the significant role of DNA methylation in the pathogenesis of major depressive disorder (MDD). Yet, whether the effects of Xiaoyaosan are linked to DNA methylation and its regulation remains unclear.

AIM OF THE STUDY

This study aims to explore and verify the molecular mechanism of Xiaoyaosan in treating MDD via integrated analysis of DNA methylation and RNA sequencing.

MATERIALS AND METHODS

In this study, a chronic unpredictable mild stress (CUMS) model was established to induce MDD in rats, which were subsequently orally treated with Xiaoyaosan, with fluoxetine as a positive control. Antidepressant effects were assessed by the open field test, sucrose preference test, and forced swimming test. Whole-genome bisulfite sequencing (WGBS) and bulk RNA sequencing were performed in the arcuate nucleus of hypothalamus to assess methylation changes and identify differentially expressed genes. Bioinformatics analyses were conducted to explore methylation alterations, RNA sequencing profiles, and their shared epigenetic as well as gene expression changes, to identify candidate genes. Finally, RT-PCR was used to validate the key differential genes.

RESULTS

Xiaoyaosan effectively reversed depressive-like behaviors. Further, Xiaoyaosan treatment involved multiple epigenetic modifications. The results of differentially methylated genes showed that there were 1353 overlapped genes between M-vs-C-hypo gene and X-vs-M-hyper gene, 5326 overlapped genes between M-vs-C-hyper gene and X-vs-M-hypo gene. GO and KEGG enrichment analyses indicated these intersecting genes were involved in biological regulation, transcription factors, appetite and endocrine control systems, etc. The analysis of differentially expressed genes from RNA sequencing revealed that there were 25 overlapping genes between the M vs C hypomethylated group and the X vs M hypermethylated group, while 81 overlapping genes were identified between the M vs C hypermethylated group and the X vs M hypomethylated group. Those differential genes regulated by methylation enriched in processes related to brain and neuronal growth, neuropeptide and hormone activation, as well as biological processes and molecular functions associated with protein translation, synthesis, transport, and localization. The integrated analysis of DNA methylation and RNA sequencing screened 14 potentially differential genes, which were associated with appetite regulation, energy metabolism, and neuroreceptor ligands. PCR verification found that Lmx1b, Abcc5, Gpc3 and Cfb showed statistical differences.

CONCLUSIONS

The antidepressant mechanism of Xiaoyaosan involves the biological regulation in the arcuate nucleus of hypothalamus, including transcription factors, neurotransmitter regulation, neural development, appetite regulation peptides, and endocrine control systems. The methylation level and regulation at the gene locus of Lmx1b, Abcc5, Gpc3, and Cfb may play a key role in the treatment of Xiaoyaosan. These findings provide new insights into the therapeutic mechanisms of Xiaoyaosan.

The piper at the gates of brain: A systematic review of surface modification strategies on lipid nanoparticles to overcome the Blood-Brain-Barrier

The Blood-Brain Barrier (BBB) significantly impedes drug delivery to the central nervous system. Nanotechnology, especially surface-functionalized lipid nanoparticles, offers innovative approaches to overcome this barrier. However, choosing an effective functionalization strategy is challenging due to the lack of detailed comparative analysis in current literature. Our systematic review examined various functionalization strategies and their impact on BBB permeability from 2041 identified articles, of which 80 were included for data extraction. Peptides were the most common modification (18) followed by mixed strategies (12) proteins (9), antibodies (7), and other strategies (8). Interestingly, 26 studies showed BBB penetration with unmodified or modified nanoparticles using commonly applied strategies such as PEGylation or surfactant addition. Statistical analysis across 42 studies showed correlation between higher in vivo permeation improvements and nanoparticle type, size, and functionalization category. The highest ratios were found for nanostructured lipid carriers or biomimetic systems, in studies with particle sizes under 150 nm, and in those applying mixed functionalization strategies. The interstudy heterogeneity we observed highlights the importance of adopting standardized evaluation protocols to enhance comparability. Our systematic review aims to provide a comparative insight and identify future research directions in the development of more effective lipid nanoparticle systems for drug delivery to the brain to help improve the treatment of neurological and psychiatric disorders and brain tumours.

Role of ABCC5 in cancer drug resistance and its potential as a therapeutic target

Over 90% of treatment failures in cancer therapy can be attributed to multidrug resistance (MDR), which can develop intracellularly or through various routes. Numerous pathways contribute to treatment resistance in cancer, but one of the most significant pathways is intracellular drug efflux and reduced drug concentrations within cells, which are controlled by overexpressed drug efflux pumps. As a member of the family of ABC transporter proteins, ABCC5 (ATP Binding Cassette Subfamily C Member 5) reduces the intracellular concentration of a drug and its subsequent effectiveness using an ATP-dependent method to pump the drug out of the cell. Numerous studies have demonstrated that ABCC5 is strongly linked to both poor prognosis and poor treatment response. In addition, elevated ABCC5 expression is noted in a wide variety of malignancies. Given that ABCC5 is regulated by several pathways in a broad range of cancer types, it is a prospective target for cancer treatment. This review examined the expression, structure, function, and role of ABCC5 in various cancer types.

The impact of ATP-binding cassette transporters in the diseased brain: Context matters

ATP-binding cassette (ABC) transporters facilitate the movement of diverse molecules across cellular membranes, including those within the CNS. While most extensively studied in microvascular endothelial cells forming the blood-brain barrier (BBB), other CNS cell types also express these transporters. Importantly, disruptions in the CNS microenvironment during disease can alter transporter expression and function. Through this comprehensive review, we explore the modulation of ABC transporters in various brain pathologies and the context-dependent consequences of these changes. For instance, downregulation of ABCB1 may exacerbate amyloid beta plaque deposition in Alzheimer's disease and facilitate neurotoxic compound entry in Parkinson's disease. Upregulation may worsen neuroinflammation by aiding chemokine-mediated CD8 T cell influx into multiple sclerosis lesions. Overall, ABC transporters at the BBB hinder drug entry, presenting challenges for effective pharmacotherapy. Understanding the context-dependent changes in ABC transporter expression and function is crucial for elucidating the etiology and developing treatments for brain diseases.

Circadian Rhythms of the Blood-Brain Barrier and Drug Delivery

The blood-brain barrier (BBB) is a critical interface separating the central nervous system from the peripheral circulation, ensuring brain homeostasis and function. Recent research has unveiled a profound connection between the BBB and circadian rhythms, the endogenous oscillations synchronizing biological processes with the 24-hour light-dark cycle. This review explores the significance of circadian rhythms in the context of BBB functions, with an emphasis on substrate passage through the BBB. Our discussion includes efflux transporters and the molecular timing mechanisms that regulate their activities. A significant focus of this review is the potential implications of chronotherapy, leveraging our knowledge of circadian rhythms for improving drug delivery to the brain. Understanding the temporal changes in BBB can lead to optimized timing of drug administration, to enhance therapeutic efficacy for neurological disorders while reducing side effects. By elucidating the interplay between circadian rhythms and drug transport across the BBB, this review offers insights into innovative therapeutic interventions.

Blood-Brain Barrier (BBB)-Crossing Strategies for Improved Treatment of CNS Disorders

Blood-brain barrier (BBB) is a special biological property of the brain neurovascular unit (including brain microvessels and capillaries), which facilitates the transport of nutrients into the central nervous system (CNS) and exchanges metabolites but restricts passage of blood-borne neurotoxic substances and drugs/xenobiotics into CNS. BBB plays a crucial role in maintaining the homeostasis and normal physiological functions of CNS but severely impedes the delivery of drugs and biotherapeutics into CNS for treatment of neurological disorders. A variety of technologies have been developed in the past decade for brain drug delivery. Most of these technologies are still in preclinical stage and some are undergoing clinical studies. Only a few have been approved by regulatory agencies for clinical applications. This chapter will overview the strategies and technologies/approaches for brain drug delivery and discuss some of the recent advances in the field.

Imaging the impact of blood-brain barrier disruption induced by focused ultrasound on P-glycoprotein function

The P-glycoprotein (P-gp/ABCB1) is a major efflux transporter which impedes the brain delivery of many drugs across the blood-brain barrier (BBB). Focused ultrasound with microbubbles (FUS) enables BBB disruption, which immediate and delayed impact on P-gp function remains unclear. Positron emission tomography (PET) imaging using the radiolabeled substrate [11C]metoclopramide provides a sensitive and translational method to study P-gp function at the living BBB. A FUS protocol was devised in rats to induce a substantial and targeted disruption of the BBB in the left hemisphere. BBB disruption was confirmed by the Evan's Blue extravasation test or the minimally-invasive contrast-enhanced MRI. The expression of P-gp was measured 24 h or 48 h after FUS using immunostaining and fluorescence microscopy. The brain kinetics of [11C]metoclopramide was studied by PET at baseline, and both immediately or 24 h after FUS, with or without half-maximum P-gp inhibition (tariquidar 1 mg/kg). In each condition (n = 4-5 rats per group), brain exposure of [11C]metoclopramide was estimated as the area-under-the-curve (AUC) in regions corresponding to the sonicated volume in the left hemisphere, and the contralateral volume. Kinetic modeling was performed to estimate the uptake clearance ratio (R1) of [11C]metoclopramide in the sonicated volume relative to the contralateral volume. In the absence of FUS, half-maximum P-gp inhibition increased brain exposure (+135.0 ± 12.9%, p < 0.05) but did not impact R1 (p > 0.05). Immediately after FUS, BBB integrity was selectively disrupted in the left hemisphere without any detectable impact on the brain kinetics of [11C]metoclopramide compared with the baseline group (p > 0.05) or the contralateral volume (p > 0.05). 24 h after FUS, BBB integrity was fully restored while P-gp expression was maximally down-regulated (-45.0 ± 4.5%, p < 0.001) in the sonicated volume. This neither impacted AUC nor R1 in the FUS + 24 h group (p > 0.05). Only when P-gp was inhibited with tariquidar were the brain exposure (+130 ± 70%) and R1(+29.1 ± 15.4%) significantly increased in the FUS + 24 h/tariquidar group, relative to the baseline group (p < 0.001). We conclude that the brain kinetics of [11C]metoclopramide specifically depends on P-gp function rather than BBB integrity. Delayed FUS-induced down-regulation of P-gp function can be detected. Our results suggest that almost complete down-regulation is required to substantially enhance the brain delivery of P-gp substrates.

A novel humanized tri-receptor transgenic mouse model of HAdV infection and pathogenesis

Human adenovirus (HAdV) is a highly virulent respiratory pathogen that poses clinical challenges in terms of diagnostics and treatment. Currently, no effective therapeutic drugs or prophylactic vaccines are available for HAdV infections. One factor contributing to this deficiency is that existing animal models, including wild-type and single-receptor transgenic mice, are unsuitable for HAdV proliferation and pathology testing. In this study, a tri-receptor transgenic mouse model expressing the three best-characterized human cellular receptors for HAdV (hCAR, hCD46, and hDSG2) was generated and validated via analysis of transgene insertion, receptor mRNA expression, and protein abundance distribution. Following HAdV-7 infection, the tri-receptor mice exhibited high transcription levels at the early and late stages of the HAdV gene, as well as viral protein expression. Furthermore, the tri-receptor mice infected with HAdV exhibited dysregulated cytokine responses and multiple tissue lesions. This transgenic mouse model represents human HAdV infection and pathogenesis with more accuracy than any other reported animal model. As such, this model facilitates the comprehensive investigation of HAdV pathogenesis as well as the evaluation of potential vaccines and therapeutic modalities for HAdV.