Search Results (457)

Intracerebral hemorrhage induces severe secondary brain injury characterized by excessive neuroinflammation and inefficient hematoma clearance, processes largely governed by microglial polarization and phagocytic activity. The immunoproteasome, an inducible proteasome isoform involved in immune regulation, has been implicated in inflammatory neurological disorders, but its role in microglial responses after ICH remains unclear. In this study, rat models of common hemorrhage, severe hemorrhage, and severe hemorrhage with hematoma aspiration were used to represent graded injury severity and post-evacuation recovery. Transcriptomic profiling at day 3 post-injury identified immunoproteasome-associated gene networks, while expression of the catalytic subunits LMP2 and LMP7, microglial polarization markers, and phagocytic receptors was analyzed by Western blotting and immunofluorescence. Severe hemorrhage markedly induced LMP2 and LMP7 expression, predominantly in Iba1⁺ microglia, accompanied by enhanced ER stress, NF-κB signaling, and M1-like polarization and reduced phagocytic marker expression. Hematoma aspiration attenuated immunoproteasome expression and restored M2-associated and phagocytic signatures. Consistently, pharmacological inhibition of immunoproteasomes in primary microglia enhanced erythrophagocytosis and promoted a reparative phenotype in vitro. These findings indicate that immunoproteasome activation links hemorrhagic severity to maladaptive microglial polarization and impaired hematoma clearance after ICH, and that reducing immunoproteasome expression may help rebalance inflammatory and phagocytic microglial functions. Full article

Despite effective antiretroviral therapy, HIV persists in diverse tissue reservoirs that pose major barriers to a cure. This review examines the heterogeneous maintenance mechanisms of HIV reservoirs in lymph nodes, intestinal mucosa, and the central nervous system (CNS). It analyzes how distinct tissue microenvironments—including immune-privileged niches, specialized cellular subsets, and local signaling networks—govern viral persistence and latency. Lymph nodes function as a dynamic hub interconnected with systemic reservoirs; the intestinal mucosa represents a site shaped by barrier integrity, microbial translocation, and mucosal immunity; the CNS constitutes a compartmentalized sanctuary protected by the blood–brain barrier. The review further discusses tissue-specific antiretroviral drug penetration and targeted clearance strategies, providing a foundation for developing multi-site intervention approaches toward HIV cure. Full article

Aging is accompanied by profound alterations in immune function, termed immunosenescence, and by a chronic, low-grade inflammatory state known as inflammaging. These processes are increasingly recognized as central drivers of age-related neurodegenerative diseases, including Alzheimer’s Disease, Parkinson’s Disease, Amyotrophic Lateral Sclerosis and Multiple Sclerosis. In the central nervous system, senescent microglia and astrocytes lose their homeostatic and neuroprotective functions, while systemic immune aging and blood–brain barrier dysfunction further amplify neuroinflammation and impair protein aggregate clearance. This sustained pro-inflammatory environment promotes synaptic dysfunction, neuronal loss and cognitive decline. Here, we synthesize current knowledge of the mechanistic links among immunosenescence, inflammaging, and neurodegeneration, highlighting innate and adaptive immune dysregulation, mitochondrial impairment, and failed resolution pathways. We further discuss emerging therapeutic strategies, including senolytics, immunoceuticals, microbiome-based interventions and advanced drug delivery systems, aimed at restoring immune homeostasis and enhancing brain resilience. By integrating mechanistic and translational insights, this review provides a framework for developing novel interventions to target immune aging in neurodegenerative diseases. Full article

Intracranial atherosclerosis (ICAS) is a distinct, inflammation-dominant vasculopathy and a leading cause of global stroke morbidity. Unlike extracranial atherosclerosis (ECAS), which often utilizes compensatory positive remodeling to maintain patency, ICAS is characterized by a unique architecture and a localized antioxidant gap that favor maladaptive negative remodeling. We critically analyze the molecular cascade initiated by the breakdown of the Piezo-type mechanosensitive ion channel component 1 (PIEZO1) and the Krüppel-like factor 2/4 (KLF2/4) mechanotransduction axis, which triggers endothelial nitric oxide synthase (eNOS) uncoupling and establishes a state of chronic inflammation. This environment facilitates the subendothelial lipid retention of oxidized low-density lipoprotein (oxLDL), a process exacerbated by the intracranial deficiency of Apolipoprotein A-I (ApoA-I) and impaired glymphatic clearance. Crucially, we evaluate how these metabolic and mechanical insults drive vascular smooth muscle cell (VSMC) phenotypic switching; the transdifferentiation of contractile VSMCs into macrophage-like foam cells accounts for up to 60% of the plaque’s lipid-laden pool and destabilizes the fibrous cap. This vascular failure directly compromises the neurovascular unit (NVU), leading to pericyte dropout and blood–brain barrier breakdown. Beyond environmental stressors, we highlight the ring finger protein 213 (RNF213) variant as a critical genetic determinant of this susceptibility. Shifting the clinical paradigm from simple luminal narrowing toward the identification of the vulnerable plaque, we discuss how High-Resolution Vessel Wall Imaging (HR-VWI) and microRNA biomarkers can identify unstable lesions. By integrating these molecular and imaging signatures, we propose a precision medicine framework centered on the NLR family pyrin domain containing 3 (NLRP3) inflammasome and the NVU to effectively mitigate the high residual recurrence risk that persists under conventional therapy. Full article

Background/Objectives: Autophagy is an evolutionarily conserved degradation and recycling pathway through which cells deliver cytoplasmic components, including toxic or damaged proteins and organelles, to lysosomes for clearance. In neurons, which are largely post-mitotic, degradative pathways are essential to prevent the accumulation of cellular waste and to maintain nutrient and energy homeostasis. Increasing evidence suggests that autophagy plays a critical role during early brain development, when neuronal circuits are established, synaptic connections are refined, and activity-dependent mechanisms shape network architecture. However, the developmental regulation of autophagy-related genes and the composition of the autophagic machinery at synapses remain poorly understood. This study aimed to characterize the maturation-dependent dynamics of autophagy–lysosomal genes and to investigate the synaptic autophagy-associated proteome during cortical development. Methods: Genome-wide transcriptomic analyses were performed in the cortical brain region across developmental stages to assess changes in the expression of autophagy–lysosomal genes. In parallel, synaptosomes were isolated and subjected to proteomic analysis to identify autophagy-related proteins associated with synaptic compartments. Results: Transcriptomic profiling revealed stage-dependent regulation of autophagy–lysosomal genes during cortical maturation. Proteomic analysis of synaptosomes identified multiple autophagy-associated proteins enriched at synaptic sites, suggesting that components of the autophagic machinery are present at synapses and may participate in synaptic remodeling and function during key phases of neuronal network formation. Conclusions: These findings provide new insights into the developmental regulation of autophagy in the brain and highlight the potential contribution of synaptic autophagy to neuronal circuit maturation. Understanding these mechanisms may help identify novel therapeutic targets for neurological disorders associated with impaired synaptic and cellular homeostasis. Full article

The discovery of the glymphatic system (GS) transformed understanding of central nervous system homeostasis by revealing a brain-wide network that facilitates cerebrospinal and interstitial fluid exchange along perivascular pathways. This system clears metabolic waste and maintains the precise ionic environment required for neuronal function through the coordinated action of astrocytic aquaporin-4 channels and intact perivascular architecture. Glioblastoma multiforme (GBM), the most aggressive primary brain tumor in adults, alters physiological barriers through pathological angiogenesis, compression of perivascular spaces, depolarization of aquaporin-4 at astrocytic endfeet, and obstruction of venous and lymphatic drainage. This narrative review synthesizes current experimental and clinical literature identified through targeted searches of PubMed and Scopus to examine interactions between glioblastoma, glymphatic system dysfunction, and tumor microenvironmental changes. To minimize selection bias, studies were categorized according to evidence source and experimental design. Evidence from rodent models and advanced imaging demonstrates as tumor growth impairs glymphatic function, the resulting dysfunction promotes tumor progression by enabling accumulation of pro-tumorigenic growth factors, inflammatory mediators, and acidic metabolites, while elevated interstitial fluid pressure limits drug delivery. Impaired antigen drainage further diminishes immune surveillance, contributing to the immunosuppressive microenvironment that limits immunotherapy efficacy. A critical evaluation of these mechanisms highlights how the glymphatic system influences disease progression and suggests novel avenues for diagnostic imaging and therapeutic intervention. Although significant challenges remain in modeling human fluid dynamics, understanding these hidden networks offers a promising frontier for strategies aimed at restoring cerebral clearance and improving clinical outcomes. Full article

Introduction: Olives have been used in traditional Mediterranean medicine for thousands of years to address the causes of inflammation, ageing and cognitive health. Traditional preparations of olive include olive oil and olive leaf extract, which are major components of diets that contribute to maintaining cognitive function and reducing neurodegenerative disease risk. Aims of the study: This systematic review aimed to synthesise experimental and limited human evidence on olive biophenols in neurodegenerative disease models, identify the most studied compounds, characterise their mechanisms of action, and evaluate key translational barriers. Materials and methods: Following PRISMA 2020 guidelines and registered with PROSPERO (CRD420251252252), primary studies investigating the effects of well-characterised olive biophenols in neurodegenerative relevant in vitro, in vivo, or human models were systematically reviewed. Each study was assessed for its design, experimental model, mechanistic outcomes and reported limitations. Risk of bias was evaluated using validated tools (SYRCLE/OHAT/ToxR) appropriate for preclinical and experimental study designs. Results: Among the 25 studies, 7 (28.0%) examined oleuropein or oleuropein aglycone, 10 (40.0%) focused on hydroxytyrosol or its derivatives, and 9 (36.0%) investigated oleocanthal. Most studies employed in vivo animal models (57.7%), predominantly transgenic mouse models of AD and toxin-induced PD models. Oleuropein-based studies reported inhibition of amyloid-β and α-synuclein aggregation with behavioural improvements. Hydroxytyrosol primarily exerted antioxidant and anti-inflammatory effects with modest cognitive benefits. Oleocanthal showed the most consistent anti-amyloid and anti-tau activity, including enhanced amyloid-β clearance across the blood–brain barrier. Most studies show a moderate risk of bias due to incomplete reporting, randomisation and blinding. Conclusions: Olive biophenols demonstrate consistent neuroprotective effects in preclinical models; however, translation to clinical application remains limited by pharmacokinetic constraints, methodological heterogeneity, and insufficient human evidence. Full article

Type 2 Diabetes (T2D) is characterized by the toxic aggregation of human islet amyloid polypeptide (hIAPP or amylin) within pancreatic β-cells. IAPP is also a neuropancreatic hormone that plays a significant role in Alzheimer’s disease (AD) by co-depositing with amyloid-beta (Aβ) and Tau, supporting the Type 3 Diabetes (T3D) hypothesis. Soluble IAPP accelerates Aβ aggregation through cross-seeding and causes neurotoxicity by impairing the blood–brain barrier and activating neuroinflammation. Melatonin inhibits these processes by disrupting hydrophobic interactions in both hIAPP and Aβ, preventing the formation of toxic β-sheet structures. Furthermore, melatonin promotes amyloid clearance via the glymphatic and lymphatic systems, protects neurons from oxidative damage, and reduces Tau hyperphosphorylation. This suggests that melatonin serves as a promising multitarget therapeutic agent for both metabolic and neurodegenerative disorders by modulating structural protein transformations. Full article

Canine cognitive dysfunction (CCD) is a common age-related neurodegenerative disorder in dogs that shares several pathological and clinical features with human Alzheimer’s disease (AD). In both species, β-amyloid (Aβ) accumulates within the brain parenchyma and cerebral vessel walls and is associated with synaptic loss, oxidative stress, mitochondrial dysfunction, and chronic neuroinflammation, ultimately leading to progressive cognitive decline. Increasing evidence indicates that impairment of brain clearance mechanisms, particularly the glymphatic system, represents a central pathogenic mechanism in both CCD and AD. The glymphatic system is a glia-dependent perivascular network involved in the clearance of Aβ and other metabolic waste products from the brain. Its function declines with aging, vascular disease, and astrocytic alterations, including changes in aquaporin-4 distribution. Reduced glymphatic and periarterial drainage promotes the retention and aggregation of Aβ and tau proteins. Compared with AD, tau pathology in CCD is generally less extensive, supporting the interpretation of CCD as an Aβ-predominant condition and a partial pathological analog of Alzheimer’s disease. Clinically, CCD is characterized by a constellation of behavioral changes including, disorientation, altered social interactions, sleep–wake cycle disturbances, a loss of housetraining, changes in activity levels, and increased anxiety, commonly summarized by the DISHAA acronym. Overall, CCD represents a valuable spontaneous large-animal model for investigating neurodegenerative mechanisms and clearance-related therapeutic targets relevant to both veterinary and human medicine. Full article

Background: The glymphatic system, essential for brain waste clearance and neuroimmune regulation, remains underexplored in the context of bipolar disorder (BD) among young populations. Methods: Using diffusion tensor image analysis along the perivascular space (DTI-ALPS), we compared ALPS indices derived from the conventional FSL-based (cFSL) pipeline with those from the individualized ALPS (iALPS) pipeline. A cohort of young adults comprising 77 individuals with BD and 289 healthy controls was analyzed to evaluate methodological consistency and to identify disorder-specific alterations in glymphatic function. Results: The two pipelines showed only moderate agreement (Lin’s concordance correlation coefficient = 0.52–0.60), suggesting that differences in ROI placement strategies significantly affect ALPS estimation. While the cFSL pipeline detected no group differences, the iALPS pipeline identified a trend-level reduction in ALPS index in patients with BD during depressive episodes, particularly in the right hemisphere (p = 0.036, uncorrected, FDR-adjusted p = 0.071). No significant glymphatic alterations were observed in individuals with early-stage BD. Conclusions: These findings suggest that glymphatic dysfunction in psychiatric disorders may be phase-specific on illness. The use of individualized and automated analytical strategies, such as the iALPS pipeline, appears to enhance sensitivity to subtle, state-related brain changes that conventional methods may overlook. This methodological advancement provides a more biologically informed framework for future large-scale and longitudinal studies aimed at elucidating the role of glymphatic function in the pathophysiology of psychiatric disorders. Full article

Background: Aging-related cognitive decline is closely associated with microglial senescence and the resulting chronic neuroinflammation. Emerging evidence identifies the cyclic GMP-AMP synthase–stimulator of interferon genes (cGAS-STING) pathway as a pivotal innate immune signaling pathway linking DNA damage to cellular senescence and the senescence-associated secretory phenotype (SASP), particularly in microglia. Targeting the formation or selective clearance of senescent cells thus emerges as a promising therapeutic approach to ameliorate cognitive dysfunction. Resveratrol has shown promise in modulating immune response and exerting anti-aging effects. However, the therapeutic potential and underlying mechanisms of resveratrol in mitigating age-associated microglial senescence and cognitive decline are not fully understood. Methods: In the present study, we employed a well-established murine model of accelerated aging induced by chronic intraperitoneal injection of D-galactose (D-gal) to elicit pronounced senescence-associated phenotypes and neuroinflammation. Resveratrol was administered via oral gavage daily for three weeks following D-gal injections. Behavioral assays were conducted to assess cognitive performance. Immunohistochemistry, quantitative PCR, and Western blot analyses were used to evaluate markers of cellular senescence, microglial activation and pro-inflammatory cytokine expression. In addition, in vitro assays in cultured microglia coupled with RNA sequencing were used to investigate the downstream signaling events following resveratrol treatment. Results: Chronic D-gal treatment induced significant cognitive impairment, enhanced microglial activation, elevated pro-inflammatory cytokine levels, and increased markers of cellular senescence in the brain. Resveratrol administration remarkably attenuated these effects, as evidenced by improved memory performance, reduced microglial senescence markers, and suppressed expression of Cxcl-10, Il-1β, and other SASP factors. Mechanistically, unbiased transcriptomic analysis revealed that the cGAS-STING signaling and neuroinflammation pathways were prominently dysregulated with double-stranded DNA-induced cellular senescence, which was effectively normalized by resveratrol in cultured microglia. Interestingly, resveratrol inhibited the translocation of STING from the endoplasmic reticulum to the Golgi apparatus and suppressed phosphorylation of TBK1, thereby blocking downstream STING signaling. Conclusions: These findings demonstrate that resveratrol mitigates microglial senescence and neuroinflammation and preserves cognitive function in D-gal-induced aging mice, at least partly through modulation of the cGAS-STING signaling. Therefore, targeting this pathway may represent a promising therapeutic strategy for age-related neuroinflammatory and cognitive disorders. Full article

Although the brain comprises only 2% of total body weight, it contains approximately 23% of the total cholesterol of the body. In the brain, cholesterol plays a critical role as a structural component of cell membranes and myelin sheaths. However, the blood–brain barrier restricts cholesterol influx from the systemic circulation into the brain. As a result, the brain synthesizes cholesterol de novo and regulates its metabolism independently. Desmosterol, a cholesterol precursor produced during cholesterol biosynthesis, and cholesterol metabolites, 24S-hydroxycholesterol and chenodeoxycholic acid, are sterols with structurally retained side chains. These side-chain-retaining sterols have traditionally been regarded as intermediates in the cholesterol synthesis process or as metabolites for cholesterol excretion, but accumulating evidence indicates that they also function as physiologically active signaling molecules that influence brain function via nuclear receptors, such as liver X receptors, and membrane receptors, such as NMDA receptors. Through nuclear receptors, these side-chain-retaining sterols regulate the transcription of genes involved in lipid transport, inflammation control, and amyloid clearance, while their membrane receptor action enables rapid synaptic effects. These side-chain-retaining sterols mediate metabolic crosstalk between neurons and glial cells and contribute to maintaining cholesterol balance in the developing brain. Furthermore, these side-chain-retaining sterols have been shown to affect amyloid-β clearance, α-synuclein aggregation, neuroinflammation, mitochondrial function, and remyelination. Dysregulation of these side-chain-retaining sterols is associated with neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Overall, side-chain-retaining sterols are important regulators of brain physiology. This review focuses on the current knowledge regarding the physiological functions of side-chain-retaining sterols in the brain and their roles in neurodegenerative diseases. Full article

The choroid plexus (CP) has traditionally been regarded as a cerebrospinal fluid-producing structure; however, increasing evidence indicates that it functions as a dynamic regulatory interface involved in immune surveillance, metabolic homeostasis, and brain clearance. Neuroimaging studies consistently report CP enlargement across aging and diverse neurological and neuropsychiatric disorders, yet the underlying cellular mechanisms remain poorly integrated. In this review, we synthesize morphological, molecular, and imaging evidence to propose a sequential degenerative model of the CP epithelium. This model comprises: (1) regulated epithelial cell loss via apical extrusion, (2) compensatory hypertrophy of residual cells, (3) mitochondrial remodeling with oncocytic-like change, and (4) progressive blood–cerebrospinal fluid barrier dysfunction. At the molecular level, alterations in epithelial adhesion systems—particularly SPINT1-mediated protease regulation and E-cadherin–based adherens junction stability—may initiate epithelial instability. Hypertrophic epithelial cells exhibit increased mitochondrial burden, reflected by Tom20 expression, which may initially support metabolic adaptation but ultimately contribute to oxidative stress and functional decline. At the macroscopic level, the cumulative effects of cell loss, hypertrophy, and mitochondrial remodeling likely underlie CP enlargement detectable by magnetic resonance imaging. This framework positions CP enlargement as an imaging-visible manifestation of epithelial stress and provides a structural–molecular basis for interpreting CP alterations in brain aging and neurodegenerative disorders. Full article

Pharmacological activation of brain Retinoid X Receptors (RXRs) enhances cognition and facilitates amyloid-beta (Aβ) clearance in Alzheimer’s disease (AD) mouse models, partly by upregulating apolipoprotein E (Apoe), a major AD genetic risk factor. However, the specific cellular contributions to these effects are unclear. Here, we used single-cell transcriptomic profiling to investigate cell subpopulation-specific responses to bexarotene, an RXR agonist, in APP/PS1 mice. Our analysis revealed that bexarotene activated cholesterol biosynthesis and lipid metabolism transcriptional programs in homeostatic astrocytes and oligodendrocytes. Astrocytes also upregulated neurodevelopmental genes, while oligodendrocytes and endothelial cells showed enhanced protein folding and cellular growth pathways. Bexarotene further modulated immune responses, promoting Aβ-responsive signatures in disease-associated microglia and reactive astrocytes while dampening pro-inflammatory responses in homeostatic microglia and endothelial cells. Furthermore, Apoe expression was significantly elevated across multiple cell types, especially in microglia and oligodendrocytes. Cell–cell communication analysis highlighted increased astrocyte-centered signaling, with APOE-driven pathways emerging as a prominent mediator. These findings clarify the molecular complexity of RXR-mediated regulation, revealing the cellular origins of bexarotene’s known effects as well as novel, cell-type-specific responses. This study provides mechanistic insights into RXR-targeted interventions and supports APOE-associated pathways as promising therapeutic targets in AD. Full article

Rett syndrome (RTT) is a neurodevelopmental disorder characterized by motor deficits, partly attributed to cerebellar dysfunction. RTT is primarily caused by mutations in the gene encoding the methyl-CpG-binding protein 2 (MECP2), which has been implicated in cholesterol homeostasis by mechanisms that remain poorly understood. Given that brain cholesterol is primarily synthesized de novo and that disrupted cholesterol homeostasis is linked to various neurological disorders, we aimed to investigate cholesterol regulation in the cerebellum of Mecp2-null mice, a well-established RTT model. We measured total cholesterol levels in cerebellar tissue and cerebellar synaptosomes and assessed the expression of genes involved in cholesterol biosynthesis and intracellular transport. Our results show significantly elevated total cholesterol in both cerebellar tissue and synaptosomes. Furthermore, we identified a marked reduction in CYP46A1 expression, which is essential for the elimination of encephalon sterols. In contrast, key cholesterol biosynthetic regulators (Srebp2, Hmgcs1, Sqle) showed no significant changes in expression, suggesting an impaired cerebellar cholesterol turnover—driven by defective clearance—rather than enhanced synthesis may underlie the metabolic imbalance observed in the cerebellum of the RTT mouse model. Altogether, these findings provide a mechanistic insight into how MeCP2 deficiency disrupts cerebellar cholesterol homeostasis and highlight cholesterol clearance pathways as potential contributors to RTT pathology and a factor to consider for further RTT therapeutic approaches. Full article