Search Results (667)

Obesity resulting from melanocortin-4 receptor (MC4R) dysfunction is characterized by combined metabolic dysregulation and maladaptive reward-related behaviors that limit the durability of existing therapies. The endocannabinoid system is a central regulator of appetite, lipid metabolism, and reward processing; however, first-generation cannabinoid receptor 1 (CB1) antagonists were limited by adverse neuropsychiatric effects. SKNY-1 is an orally active tetrahydrocannabivarin (THCV) analog designed to engage pathway-biased CB1 signaling, modulate cannabinoid receptor 2 (CB2), and selectively inhibit monoamine oxidase B (MAO-B), with the objective of addressing both metabolic and behavioral components of obesity while minimizing central nervous system liability through biased CB1 signaling, CB2 modulation, and potential complementary MAO-B inhibition. Here, we integrated in vitro pharmacological profiling of SKNY-1 with in vivo evaluation in an adult mc4r(G894C) zebrafish model exhibiting obesity-associated metabolic and reward-related phenotypes. In vitro, SKNY-1 displayed low-potency modulation of CB1 cyclic AMP signaling (EC₅₀ ~30 µM) but more potent antagonism of the CB1 β-arrestin pathway (IC₅₀ ~6 µM), consistent with differential CB1 pathway modulation. SKNY-1 acted as a CB2 partial agonist (EC₅₀ ~0.1 µM), with antagonist activity emerging at higher concentrations, and selectively inhibited MAO-B at low affinity with no activity against MAO-A. In vivo, mc4r(G894C) zebrafish mutants exhibited dyslipidemia, hepatic triglyceride accumulation, altered appetite-regulatory gene expression, increased metabolic rate, and enhanced compulsive high-calorie feeding and nicotine-seeking behaviors. Oral administration of SKNY-1 for six days produced dose-dependent effects. Both doses normalized total cholesterol and low-density lipoprotein levels and reduced hepatic triglycerides toward wild-type values without affecting circulating triglycerides. The higher dose (200 ng per fish per day) induced significant body weight reduction while preserving body density and attenuated reward-associated feeding and nicotine-seeking behaviors. The lower dose (20 ng per fish per day) more effectively normalized the leptin a-to-ghrelin expression ratio. Collectively, these findings demonstrate that SKNY-1 engages integrated endocannabinoid and potential dopaminergic mechanisms to improve metabolic parameters and attenuate maladaptive reward-related behaviors in an MC4R-deficient vertebrate model, supporting its further translational investigation for obesity complicated by compulsive eating and substance-seeking behaviors. Full article

Atherosclerosis is caused by inflammatory processes that alter the permeability of arterial wall cells and leucocyte recruitment, leading to oxidation of low-density lipoproteins in the artery. The use of dietary polyphenols as antioxidants seems promising. Herein, molecular docking-based screening was initially used to predict the interactions of epicatechin and hydroxytyrosol on multiple cytokines that can trigger atherosclerosis development. Computational results show that epicatechin and hydroxytyrosol interact with the cytokines, namely, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein 1 (MCP-1), granulocyte–macrophage colony-stimulating factor, leukocyte differentiation antigen CD36, and oxidized low-density lipoprotein receptor-1. Cytotoxicity of both the bioactive compounds to human monocytic THP-1 macrophages was evaluated by lactate dehydrogenase and crystal violet assays. ROS activity evaluation was done for the phytocompounds followed by monocyte migration assay for MCP-1. The expression levels of selected biomarkers were further assessed by quantitative polymerase chain reaction. Inhibition of these atherosclerotic biomarkers may limit the atherogenic effect. Notably, these two polyphenols at a concentration of 0–125 µg/mL for 24 h showed no cytotoxicity on THP-1 macrophages and exhibited decreased ROS production and MCP-1 levels. The genes implicated in the early stages of inflammation are potential therapeutic targets to effectively reduce atherogenesis and prevent CVD. The interaction between the selected cytokines and the two natural compounds indicates their potential ability to inhibit the inflammation in vitro and exhibit anti-atherogenic effects. Hence, epicatechin and hydroxytyrosol possess significant anti-atherosclerotic effects and, in combination, could contribute positively to the treatment of atherosclerosis. Full article

Neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD), are increasingly recognized as conditions with a complex, multisystemic origin. ASD frequently co-occurs with other neurological conditions, such as epilepsy. We report a female patient, born to unrelated healthy parents, presenting with a complex clinical phenotype characterized by ASD level 1 with fluent speech, borderline intellectual functioning (BIF), coordination disorder, and epilepsy. Trio-based whole-exome sequencing (WES) revealed a de novo variant in the USP24 gene (c.3155G>T; p.Ser1052Ile), classified as likely pathogenic according to ACMG criteria (PS2, PM2, PP2, BP4). USP24 has previously been associated with Parkinson’s disease and has recently emerged as a candidate risk gene for ASD. In addition, WES detected two variants of uncertain significance (VUS), both inherited from the clinically unaffected father: c.388G>C (p.Gly130Arg) in NRXN2 and c.6395C>A (p.Ser2132Tyr) in LRP2. Although neither gene shows a fully penetrant causal relationship with the observed phenotype, both have been implicated in neurodevelopmental disorders. Array-CGH analysis did not reveal pathogenic copy number variants; however, the presence of additional genetic contributors not detectable by WES cannot be excluded. Overall, the de novo USP24 variant likely represents the primary genetic driver of the phenotype, while the potential contribution of the inherited NRXN2 and LRP2 variants remains plausible. This case underscores the complexity of the genetic architecture underlying NDDs and supports a model involving cumulative effects of multiple variants rather than a strictly multigenic interaction. Full article

Atherosclerotic cardiovascular disease (ASCVD) is increasingly recognized not merely as a lipid-storage disorder but as a chronic, lipid-driven inflammatory condition of the arterial wall. Despite the widespread use of statins and other lipid-lowering therapies, a substantial “residual inflammatory risk” persists, propelling the search for targeted immunopharmacological interventions. At the forefront of this inflammatory cascade is the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which serves as a central orchestrator of vascular inflammation by linking metabolic dysregulation to the innate immune response. Atherogenic danger signals—such as oxidized low-density lipoprotein (ox-LDL) and cholesterol crystals—trigger NLRP3 activation through reactive oxygen species (ROS) generation, lysosomal rupture, and potassium efflux. This, in turn, drives the maturation of pro-inflammatory cytokines (IL-1β and IL-18) and initiates macrophage pyroptosis. In this review, we systematically evaluate the immunomodulatory potential of natural products—both complex extracts and single bioactive compounds—in inhibiting the NLRP3 inflammasome axis. We detail the pharmacological mechanisms by which these natural agents intercept inflammatory signaling at multiple stages: suppressing TLR4/NF-κB-mediated priming, scavenging mitochondrial ROS, and restoring autophagic flux via AMPK/mTOR pathways to prevent inflammasome assembly. By critically analyzing these pathways, we highlight natural product-derived inhibitors as a promising class of immunomodulators capable of attenuating atherosclerotic progression and addressing the persistent challenge of residual inflammatory risk. Full article

This study aimed to systematically elucidate the antihyperlipidemic mechanism of paeoniflorin, and we adopted an integrated multi-omics strategy to screen the key molecular targets and regulatory pathways involved in its action, followed by experimental validation to verify the potential regulatory effects of paeoniflorin on the screened targets and metabolic processes. Rats with high-fat diet-induced hyperlipidemia received paeoniflorin treatment. Liver histopathology was evaluated using hematoxylin–eosin and Oil Red O staining. Serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bile acids, activated partial thromboplastin time, prothrombin time, thrombin time, and fibrinogen were measured using a biochemical analyzer. Integrated multi-omics analyses were performed to investigate paeoniflorin’s lipid-lowering mechanism. Critical pathways and targets identified were validated using Western blotting. Paeoniflorin alleviated pathological liver damage in hyperlipidemic rats and improved blood lipid levels, coagulation function, and liver function markers. Multi-omics analyses verified that paeoniflorin downregulated the expression of TREM-1, TLR4, NF-κB, TNF-α, and IL-1β, thereby alleviating hepatic inflammation. Paeoniflorin also upregulated the expression of low-density lipoprotein receptors (LDLR), liver X receptor alpha (LXRα), and ATP-binding cassette subfamily G member 1 (ABCG1), while downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9) expression, contributing to balanced cholesterol metabolism. Paeoniflorin normalized glycerophospholipid and branched-chain amino acid metabolism, which correlated with reduced inflammation and improved cholesterol metabolism. Paeoniflorin ameliorates hyperlipidemia through multitarget mechanisms, potentially by suppressing the TREM-1-TLR4-NF-κB signaling pathway to reduce inflammation and by regulating cholesterol metabolism via the PCSK9-LDLR and LXRα-ABCG1 pathways. Full article

Alpha-2-macroglobulin (α₂M) is a conserved plasma glycoprotein traditionally known for its broad-spectrum protease inhibitory activity. However, emerging evidence indicates that its activated form, α₂M*, generated via proteolytic cleavage or nucleophilic attack, functions as a versatile signaling ligand. By engaging specific cell-surface receptors, most notably low-density lipoprotein receptor-related protein 1 (LRP1) and glucose-regulated protein 78 (GRP78), α₂M* orchestrates a diverse array of intracellular programs, including the PI3K/Akt/mTOR, MAPK/ERK, and JAK/STAT cascades, as well as mechanosensitive YAP/TAZ signaling. These pathways collectively govern fundamental cellular processes such as proliferation, metabolic reprogramming, cytoskeletal remodeling, and inflammatory adaptation across various cell types, including macrophages, cardiomyocytes, and malignant cells. Altogether, this review synthesizes current knowledge on α₂M activation, structural transitions, receptor interactions, and downstream signaling, highlighting the expanding functional landscape of α₂M* as a potent regulator of intracellular communication with implications for physiology and disease. Full article

Cardiovascular diseases (CVDs) remain the leading cause of global mortality, with aortic pathologies such as atherosclerosis and thoracic aortic aneurysm posing significant risks due to their asymptomatic nature and potential fatal complications. This study investigates molecular mechanisms underlying CVDs by examining key cellular components of the aortic wall—vascular smooth muscle cells (VSMCs), fibroblasts, and macrophages—and their responses to low-density lipoproteins (LDLs). Using in vitro models, we analyzed phenotypic characteristics, LDL internalization capacity, and secretion/expression of pro-inflammatory mediators (IL-6, IL-8, IL-1β, CCL2) in primary VSMCs (from tunica intima and media), fibroblasts (977hTERT), and THP-1 macrophages. Fluorescence staining with BDP 630/650 revealed that all cell types internalize LDLs, with macrophages showing the highest lipid accumulation. ELISA and RT-qPCR demonstrated cell-specific patterns of cytokine secretion and gene expression, both in control conditions and after LDL exposure. The results indicate that VSMCs and fibroblasts, normally involved in vascular tone maintenance and extracellular matrix (ECM) synthesis, acquire pro-inflammatory features under pathological conditions, including increased secretion of IL-6, IL-8, and CCL2. Macrophages exhibited enhanced expression of the scavenger receptor CD36 and pro-inflammatory cytokines (especially IL-1β) after LDL treatment. Full article

Endothelial cells are key regulators of vascular homeostasis, and their dysfunction plays a central role in the development of atherosclerosis and other cardiovascular diseases. Multinucleated variant endothelial cells (MVECs) have been described in pathological vascular regions; however, their functional properties remain poorly characterized. The aim of the present study was to compare lipid handling, inflammatory activation, barrier-associated features, and secretory profiles of typical endothelial cells (TECs, EA.hy926 line) and MVECs under low-density lipoprotein (LDL) exposure. MVECs were generated by polyethylene glycol-induced fusion of EA.hy926 cells and incubated with LDL under standardized conditions. Intracellular cholesterol accumulation was assessed biochemically, cytokine secretion was quantified by ELISA, gene expression of inflammatory, endothelial, junctional, and vasoactive markers was analyzed by quantitative real-time PCR, and the endothelial secretome was characterized using data-independent acquisition liquid chromatography–tandem mass spectrometry (DIA-LC-MS). MVECs demonstrated enhanced cholesterol accumulation compared with TECs following LDL exposure. At the transcriptional level, MVECs were characterized by elevated basal expression of proinflammatory markers, including IL1B, IL6, and NFKB1, and showed a markedly amplified IL6 and IL8 response to LDL. In parallel, MVECs exhibited reduced expression of genes associated with antioxidant defense (SOD1), barrier integrity (TJP1), and hemostatic function (VWF). Consistent with transcriptional data, mass spectrometry-based secretome analysis revealed decreased secretion of von Willebrand factor (vWF), vascular endothelial growth factor C (VEGFC), and endothelin-1 (EDN1) by MVECs, accompanied by increased secretion of tissue-type plasminogen activator (t-PA). Functional enrichment analysis of secretome-associated proteins highlighted pathways related to extracellular matrix–receptor interaction, focal adhesion, cell adhesion molecules, complement and coagulation cascades, and leukocyte transendothelial migration. In contrast, TECs demonstrated a more pronounced transcriptional response in EDN1, consistent with their role in vascular tone regulation. Immunocytochemical analysis further revealed altered subcellular distribution of the tight junction protein ZO-1 in MVECs, indicating junctional destabilization. Taken together, these results indicate that MVECs represent a distinct endothelial phenotype characterized by enhanced lipid accumulation, sustained proinflammatory activation, altered secretory signaling, and reduced barrier and hemostatic potential. Such features suggest that MVECs may contribute to the maintenance of chronic endothelial dysfunction and vascular inflammation under conditions of lipid overload. Full article

(1) Background: Adult neurogenesis within the hippocampus modulates hippocampal memory and is often dysregulated in diseases that cause memory dysfunction, notably Alzheimer’s disease. We have discovered a novel modulator of hippocampal neurogenesis—low-density lipoprotein receptor-related protein 1 (LRP1). (2) Methods: Using an inducible knockout of LRP1, male and female mice were subject to loss of LRP1, specifically in adult-born neural stem cells at 3 months of age. (3) Results: After 6 months with the knockout, animals without LRP1 in adult-born neural stem cells displayed behavioral phenotypes consistent with deficits in working memory and hippocampal-mediated spatial memory. We also found that over time, increasing numbers of adult-born LRP1-knockout neurons were present, although those neurons were morphologically less complex with fewer dendrites than controls. Our data suggest that the increase in the total number of adult-born neurons 6 months after knockout is due to a subtle increase in hippocampal proliferation over time. (4) Conclusions: Altogether, our data suggest that LRP1 is an important and previously unknown regulator of hippocampal neurogenesis. Full article

Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes low-density lipoprotein receptor degradation and thereby regulates plasma LDL cholesterol levels. Although PCSK9 is primarily produced by the liver, it has been detected in platelets; however, the origin and functional relevance of platelet-associated PCSK9 remain unclear. Methods: Washed platelets (WPs) were isolated from normolipidemic subjects. Endogenous platelet PCSK9 content was quantified by ELISA, and PCSK9 molecular forms were assessed by immunoblotting. The WPs were incubated with recombinant PCSK9 (recPCSK9), and platelet aggregation in response to arachidonic acid (AA) or thrombin (Thr) was evaluated. The effects of LDL- or HDL-bound PCSK9 on platelet aggregation were also examined. Results: Platelets from normolipidemic subjects contained measurable amounts of PCSK9 (0.84 ± 0.27 ng/mg protein), which increased to 2.91 ± 0.53 ng/mg protein following incubation with recPCSK9. Exposure to recPCSK9 significantly enhanced AA- and Thr-induced platelet aggregation. In contrast, LDL and HDL inhibited platelet aggregation independently of their PCSK9 content. Conclusions: Human platelets contain endogenous PCSK9 and can accumulate additional PCSK9 from the extracellular environment. Exogenous PCSK9 enhances platelet aggregation, supporting a potential prothrombotic role for circulating PCSK9 even in normolipidemic individuals. These findings provide new insight into the complex interplay between PCSK9, lipoproteins, and platelet function. Full article

Although blood–brain barrier (BBB) models are of great value in investigating neurological diseases, the structural complexity and intricate function based on cell–cell interactions of the BBB bring various limitations to the applications of existing models. In this study, a novel BBB micro-organoid model was established by culturing neurovascular unit (NVU) cells on a decellularized squid mantle scaffold (DSMS) film to reconstitute a more authentic and reliable NVU microenvironment for in vitro research. The DSMS applied was obtained from squid mantle scaffolds via decellularization, followed by defatting, and showed good biocompatibility with no cytotoxicity. The DSMS film was finally prepared by lyophilization. The lyophilized film exhibited a void ratio and pore size suitable for the adhesion and growth of endothelial cells (hCMEC/D3) and astrocytes (hACs), which led to the formation of a BBB-like spatial structure. The BBB micro-organoid model exhibited functional barrier properties, including an effective transendothelial electrical resistance (TEER) of approximately 230 Ω/cm², restricted permeability to macromolecules—with apparent permeability coefficients (Papp) of 6.3 × 10⁻⁷ cm/s for 10 kDa and 2.7 × 10⁻⁷ cm/s for 70 kDa FITC–dextran—and expression of tight junctional complex (TJC) proteins such as vascular endothelial cadherin (VE-cad) and Zonula Occludens-1 (ZO-1). Furthermore, low-density lipoprotein receptor-related protein 1 (LRP1), a key receptor stably expressed in these two NVU cell types, was utilized as a critical indicator to assess the integrity of the BBB micro-organ model and its responsiveness to pathophysiological stimuli, particularly under thrombotic conditions. This study not only validates the feasibility of constructing a functionally competent BBB micro-organ model using DSMS films integrated with NVU cells but also provides a promising in vitro platform for subsequent studies on the BBB-related pathological mechanisms and the evaluation of drug permeability across the BBB. Full article

Chronic exposure to the cyanotoxin microcystin-LR is an emerging environmental driver of non-alcoholic fatty liver disease (NAFLD); however, the initiating molecular events at sub-lethal, environmentally relevant concentrations remain elusive. Current safety guidelines focus primarily on acute injury, potentially overlooking silent metabolic disruption. The present study investigates the early metabolic toxicity of chronic low-dose microcystin-LR (10 µg/L) in a 7-week rat model, specifically focusing on pre-symptomatic perturbations in lipid homeostasis. By integrating biochemical profiling with multivariate systems toxicology (LASSO and PLS-DA), we identified a specific phenotype of “Silent Hepatic Total Cholesterol Accumulation” (T-CHOL +16%, p = 0.01) occurring in the absence of systemic dyslipidemia or overt liver injury. Mechanistic analysis revealed a specific dual failure of cholesterol homeostasis, characterized by the paradoxical upregulation of the influx transporter Ldlr (LASSO coef +0.661) and the suppression of the efflux transporter Abcg1 (PLS1 loading −0.358). Crucially, Ldlr upregulation occurred despite the concomitant transcriptional downregulation of Srebp2 (Spearman ρ = −0.585), indicating a regulatory uncoupling mechanism. We propose that microcystin-LR-induced protein phosphatase 2A (PP2A) inhibition likely drives this uncoupling via a post-transcriptional override—possibly involving ERK/RSK-mediated Ldlr mRNA stabilization. Concurrently, this inhibition appears to block LXR-mediated Abcg1 expression through sustained AMPK hyperactivation resulting from the loss of dephosphorylation. These findings indicate liver-specific cholesterol accumulation as the critical first step of environmental NAFLD pathogenesis, suggesting that current WHO guidelines (1 µg/L) may require re-evaluation regarding metabolic safety. We propose the hepatic Ldlr/Abcg1 ratio as a potential early biomarker for revised risk assessment. Full article

Prostate cancer (PCa) is the most common male cancer and the second leading cause of cancer death in men. Androgen deprivation therapy (ADT) has been widely used as the first-line treatment for PCa. However, most PCa will progress to castration-resistant PCa (CRPC) that resists ADT 1 to 3 years after the treatment. Steroidogenesis from cholesterol is one of the mechanisms leading to ADT resistance. In PCa cells, low-density lipoprotein (LDL) mediated uptake is the major venue to acquire cholesterol. However, the mechanism of regulating this process is not fully understood. Fibroblast growth factor receptor 1 (FGFR1) is a receptor tyrosine kinase (RTK) that is ectopically expressed in PCa cells and promotes PCa progression by activating downstream signaling pathways. To comprehensively determine the roles of FGFR1 in PCa, we generated FGFR1-null DU145 cells and compared the transcriptomes of FGFR1-null and wild-type cells. We found that ablation of FGFR1 reduced the expression of genes promoting LDL uptake and de novo synthesis of cholesterol, thereby reducing the overall cholesterol pool in PCa cells. Detailed mechanistic studies further revealed that FGFR1 boosted the activation of sterol regulatory element-binding protein 2 (SREBP2) through ERK-dependent phosphorylation and cleavage, which, in turn, increased the expression of low-density lipoprotein receptor (LDLR) and enzymes involved in de novo cholesterol synthesis. Furthermore, in silico analyses demonstrated that high expression of FGFR1 was associated with high LDLR expression and clinicopathological features in PCa. Collectively, our data unveiled a previously unrecognized therapeutic avenue for CRPC by targeting FGFR1-driven cholesterol uptake and de novo synthesis. Full article

The blood–brain barrier (BBB) restricts therapeutic delivery to the central nervous system (CNS), hindering the treatment of neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, brain cancers, and stroke. Aptamers, short single-stranded DNA or RNA oligonucleotides that can fold into unique 3D shapes and bind to specific target molecules, offer high affinity and specificity, low immunogenicity, and promising BBB penetration via receptor-mediated transcytosis targeting receptors such as the transferrin receptor (TfR) and low-density lipoprotein receptor-related protein 1 (LRP1). This review examines aptamer design through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) and its variants, mechanisms of BBB crossing, and applications in CNS disorders. Recent advances, including in silico optimization, in vivo SELEX, BBB chip-based MPS-SELEX, and nanoparticle–aptamer hybrids, have identified brain-penetrating aptamers and enhanced the brain delivery efficiency. This review highlights the potential of aptamers to transform CNS-targeted therapies. Full article