Search Results (1,264)

Background/Objectives. Parkinson’s disease (PD) is a multifactorial neurodegenerative disorder characterized by dopaminergic neuron loss, α-synuclein pathology, neuroinflammation, and cognitive decline. Synaptamide (N-Docosahexaenoylethanolamine (DHEA)) is an endogenous lipid mediator with documented anti-inflammatory and neurogenic properties, but its effects in PD models remain unexplored. This study aimed to evaluate the neuroprotective potential of synaptamide in a subchronic MPTP-induced mouse model of PD. Methods. Male C57BL/6 mice received MPTP (30 mg/kg/day, i.p., 5 days) with or without synaptamide (10 mg/kg/day, s.c., 13 days). Behavioral tests (open field, Y-maze, elevated plus maze, novel object recognition (NOR)) were performed, followed by immunohistochemical analysis of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra, and Western blotting for α-synuclein, p-α-synuclein, TH, and IL1β in brain homogenates and serum. In vitro Neuro-2a cells were co-treated with MPP⁺ (100 µM) and synaptamide (0.1–10 µM) for cytotoxicity assessment (MTS assay). Results. Synaptamide (10 µM) significantly attenuated MPP⁺-induced cytotoxicity in Neuro-2a cells. In vivo, MPTP caused a marked loss of TH⁺-neurons in the substantia nigra, which was prevented by synaptamide treatment. Importantly, this subchronic MPTP model recapitulates early biochemical alterations (e.g., α-synuclein phosphorylation at Ser129) rather than mature Lewy body pathology, a limitation that should be considered when interpreting these findings. Although no motor deficits or anxiety-like behavior were observed, the NOR test revealed MPTP-induced long-term memory impairment, which was fully restored by synaptamide. Conclusions. These findings suggest that synaptamide may exert effects on pathological processes associated with PD, warranting further investigation into its potential role in combination or supportive therapy for this disease. Full article

We analyze data indicating that a set of currently marketed FDA/EMA-approved drugs used to treat parkinsonism, extrapyramidal side effects of antipsychotic drugs, or overactive bladder may have the potential to slow the growth of glioblastoma; diffuse midline glioma, H3K27-altered (DMG); and a particular form of DMG growing in the pons of children, diffuse intrinsic pontine glioma (DIPG). These gliomas are typically associated with poor prognosis. Clinical trials evaluating conventional chemotherapeutic drugs have failed to improve DIPG survival. Our analysis of the biochemistry and physiology of DMG and DIPG concludes that neuronal acetylcholinergic agonisms at muscarinic receptors M1 and M3 on primitive oligodendrocyte precursor cells (OPCs) are trophic, growth-stimulating factors in DMG/DIPG growth. A set of muscarinic receptor inhibitors—benztropine, biperiden, and trihexyphenidyl—is used clinically to treat Parkinson’s disease or the parkinsonian side effects from antipsychotic medicines. Another muscarinic inhibitor, oxybutynin, is used to treat overactive bladder. All four drugs may impose dose-related side effects inherent to muscarinic receptor inhibition, such as xerostomia, asthenia, and mild cognitive impairment. We recount the evidence for the inhibition of OPC proliferation and migration mediated by these four M1/M3 inhibitors and report details on the rationale for selecting oxybutynin as the primary candidate for adjuvant therapy in DMG/DIPG. We chose oxybutynin as the first choice to study in DMG and DIPG compared to other antimuscarinic drugs based on its (i) high brain-tissue concentration, (ii) relatively stronger M3 inhibition, (iii) lower side-effect propensity than scopolamine, (iv) wide availability, and (v) the absence of H1 antihistamine or dopaminergic effects. Given the rapidly fatal nature of DMG and DIPG, the potential of oxybutynin for growth slowing may outweigh the associated risks and mild side-effect burdens. Full article

Biokinetic complexities (plastic sorption, protein binding, and cellular accumulation) may cause large discrepancies between nominal and biologically effective concentrations of test compounds assessed by new approach methods (NAMs). This case study was performed to explore a generally applicable workflow that addresses biokinetic complexities in the context of NAM-based hazard testing for next-generation risk assessment (NGRA). The pesticide tebufenpyrad (TEBU) is a challenging test compound, as it (i) is hydrophobic, (ii) has an intracellular target (mitochondrial respiration), and (iii) is acting at low concentrations (susceptible to biokinetic complexities). In the newly established NeuriTox-M neurotoxicity assay, based on human dopaminergic (LUHMES) neuron cultures, TEBU showed toxic effects at 20 nM. Mass spectrometric analyses of various experimental setups showed that a large fraction (75% to >90%) of TEBU was adsorbed to plastic. This effect was strongly attenuated by albumin in the medium. Cells, cultured on plastic, were considered unsuitable to assess cellular uptake. Therefore, alternatives were explored: when cells were used as suspension cultures (3% v/v) in albumin-containing medium, analysis worked best. Under such conditions, the concentration ratio (cells/medium) of TEBU was around 10. Data from an in vitro distribution (VIVD) model were in good agreement with the measurements. VIVD predicted the unbound medium TEBU concentration (C_u) to be 2–3 orders of magnitude below the nominal concentration and the total cellular concentration to be 10–100-fold above. Standard cell culture assays showed that the medium albumin content indeed altered the TEBU toxicity threshold. More such studies are needed to embed biokinetics information into NGRA. Full article

Background: Acute carbon monoxide (CO) poisoning can cause delayed neuropsychiatric sequelae (DNS) after a latent period, yet its pathophysiology remains poorly understood because of the lack of reproducible experimental models. Methods: We established a rat model of DNS using acute CO poisoning (6500 ppm for 25 min). Behavioral assessments evaluated cognition, locomotion, sensorimotor function, exploratory behavior, and reward responsiveness. Histopathological analyses assessed brain injury, and regional monoamine concentrations were quantified using high-performance liquid chromatography. Results: CO-exposed rats developed delayed and progressive behavioral abnormalities, including impaired spatial working memory, reduced locomotor activity, sensorimotor dysfunction, and diminished exploratory behavior. At 4 weeks, CO-exposed rats showed reduced Y-maze alternation (49.3% vs. 72.2%, p < 0.0001), complete loss of tape-removal success (0% vs. 100%, p < 0.001), reduced digging behavior (10.1 ± 6.9 vs. 27.4 ± 3.9, p < 0.01), and decreased locomotor activity (330.5 ± 172.1 vs. 730.5 ± 139.5 cm, p < 0.01). In contrast, olfactory discrimination, sucrose preference, and grip strength were preserved. Histopathology demonstrated persistent neuronal and inflammatory alterations. Dopamine concentrations were significantly reduced in the cortex and basal ganglia, whereas thalamic serotonin levels were increased following CO poisoning. Conclusion: Acute CO poisoning induces a reproducible DNS characterized by progressive behavioral impairment, persistent histopathological abnormalities, and regional monoaminergic dysregulation. These findings support the concept that DNS is an evolving neuropathological process and identify dopaminergic pathways as potential therapeutic targets. Full article

The dopamine D₃ receptor (D₃R) has long been considered a secondary target in the treatment of Parkinson’s disease (PD), with therapeutic strategies primarily focused on D₂ receptor–mediated motor control. However, accumulating evidence now supports D₃R as a functionally distinct dopaminergic receptor subtype with specific relevance to non-motor symptom domains and dopaminergic signaling under hypodopaminergic conditions. Recent advances in high-resolution structural biology have elucidated the molecular basis of D₃R/D₂R discrimination, revealing how subtle residue-level and microstructural differences within a conserved G protein–coupled receptor framework shape ligand recognition and receptor activation. In parallel, the emergence of ligand-dependent biased signaling has refined current understanding of D₃R pharmacology. Selected ligands can preferentially engage Gα_i/o-mediated pathways while limiting β-arrestin recruitment and associated regulatory processes, providing a mechanistic rationale for more stable modulation of mesolimbic dopaminergic circuits involved in affective and motivational regulation. Beyond symptomatic modulation, preclinical studies suggest that D₃R signaling may influence neuronal resilience, synaptic plasticity, and adaptive responses to dopaminergic injury; however, such effects remain experimental and have not been demonstrated in clinical PD. This review integrates recent structural, signaling, and functional insights into D₃R biology, with particular emphasis on biased agonism and emerging therapeutic concepts. Although D₃R-targeted strategies do not currently represent disease-modifying interventions, they offer a rational framework for the development of next-generation dopaminergic therapies aimed at improving precision, tolerability, and long-term signaling stability in Parkinson’s disease. Full article

Parkinson’s disease (PD) is defined by the progressive degeneration of dopaminergic neurons within the substantia nigra and the pathological accumulation of α-synuclein (α-syn) aggregates. Beyond these intracellular hallmarks, the extracellular matrix (ECM) has emerged as an active regulator of synaptic dysfunction, neuroinflammation, and disease progression. Recent multi-omics evidence, including transcriptomic and proteomic profiling of post-mortem tissue and iPSC-derived neurons, demonstrates consistent dysregulation of ECM components across both sporadic and genetic PD subtypes—typified by downregulation of basement membrane collagens (COL4A) and integrin signaling (ITGB1), alongside upregulation of matrix metalloproteinases (MMPs). These alterations destabilize perineuronal nets (PNNs), allow prion-like α-syn propagation, and promote glial activation through TLR-mediated signaling. Circulating ECM-derived neoepitopes (C1M, C4M) may complement neurofilament light chain as prognostic biomarkers of disease progression, although prospective validation remains necessary. Pharmacological strategies targeting MMP activity (e.g., doxycycline), integrin–FAK signaling (ATN-161), and MMP–TIMP balance (mesenchymal stem cells) represent emerging therapeutic avenues, though clinical evidence in PD remains limited. This review synthesizes current evidence on ECM dysregulation in PD and discusses its implications for biomarker development and disease-modifying intervention. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder traditionally defined by dopaminergic neuronal loss and Lewy body pathology; however, increasing evidence indicates that metabolic dysfunction contributes to both motor and non-motor manifestations of disease. While metabolomics studies in PD have largely focused on peripheral biofluids or subcortical brain regions, metabolic remodeling within cortical regions critical for cognition remains poorly characterized. Here, we applied LC-MS/MS-based untargeted metabolomics to post-mortem frontal cortex tissue from PD and neurologically normal control donors, with statistical models adjusted for age, sex, and post-mortem interval. A total of 893 metabolites were quantified, of which 234 exhibited significant differential abundance following false discovery rate correction. Pathway enrichment and network-based integration revealed coordinated metabolic remodeling characterized by predicted inhibition of β-alanine metabolism and pantothenate-dependent coenzyme A biosynthesis alongside activation of amino acid, vitamin B-dependent, cofactor-related, redox-associated, oxidative stress, and inflammatory pathways. Recurrent alterations in pantothenic acid, β-alanine-related intermediates, arginine- and histidine-derived metabolites, lumichrome, and vitamin B₆-associated species may reflect cortical metabolic perturbations associated with mitochondrial bioenergetic vulnerability and oxidative stress. Together, these findings indicate selective metabolic vulnerability in the PD frontal cortex rather than diffuse metabolic collapse. Full article

α-synuclein (α-syn) aggregation in dopaminergic neurons is a central event in Parkinson’s disease (PD) pathogenesis. Immunotherapeutic strategies targeting α-syn, including passive and active approaches, aim to inhibit aggregation, propagation, and toxicity of pathological species while promoting their clearance via immune mechanisms. This review summarizes α-syn directed immunotherapies evaluated in in silico, in vitro, and in vivo models, as well as early phase clinical trials, focusing on how epitope selection and antibody formats influence efficacy, safety, and target engagement. Data on monoclonal antibody, peptide, and protein-based vaccines, and structure-guided immunogens were analyzed, integrating behavioral, neuropathological, proteomic, and structural outcomes alongside biomarker development for α-syn species in cerebrospinal fluid and peripheral compartments. Clinical evidence indicates that several candidates induce sustained anti-α-syn antibody responses with acceptable safety profiles and signs of pharmacodynamic engagement, including reductions in free or oligomeric α-syn. However, consistent long-term clinical benefits remain unproven, highlighting the gap between preclinical success and disease modification in humans. Advances in structural biology and proteomics support rational epitope selection and improved immunogen design, reinforcing α-syn-targeted immunotherapy as a promising yet experimental strategy for PD, and highlighting the need for mechanistically oriented, biomarker-driven clinical trials initiated in well-characterized prodromal and early-stage cohorts. Full article

Aminochrome, an endogenous neurotoxin, has been implicated in the loss of neuromelanin-containing dopaminergic neurons in the nigrostriatal system in Parkinson’s disease. Although aminochrome-induced oxidative stress and its inhibitory effects on microtubule polymerization are well documented, its impact on protein aggregation remains poorly understood. The aim of this research was to evaluate the effects of aminochrome on protein aggregate accumulation in SH-SY5Y cells differentiated into dopaminergic neurons. While the role of aminochrome in autophagy has been described, its direct effect on autophagosome–lysosome fusion has not been studied. Our findings reveal that aminochrome, like vinblastine, delays autophagosome–lysosome fusion and induces cell death. This inhibitory effect was also observed in the presence of autophagy inducers, which partially attenuated aminochrome-induced cell death. Under these conditions of disruptions in autophagosome–lysosome fusion, a marked accumulation of perinuclear vimentin and ubiquitin aggregates was observed. Aminochrome also increased colocalization between vimentin and ubiquitin. Interestingly, ubiquitin aggregates were also detected within the nucleus. These findings suggest that aminochrome-induced disruption of the microtubule network, particularly its impairment of autophagosome–lysosome fusion and promotion of protein aggregation, may represent a critical mechanism leading to cell death. In addition, inhibition of autophagosome–lysosome fusion may contribute to the accumulation of perinuclear and nuclear protein aggregates, which may be associated with either toxic or non-toxic pathways. Our findings underscore the therapeutic potential of targeting both microtubule stabilization and proteostasis pathways, including autophagy and the ubiquitin–proteasome system (UPS), in Parkinson’s disease, highlighting the need for further research into nuclear proteotoxicity mechanisms. Full article

Cell replacement therapy is a promising investigational approach for Parkinson’s disease (PD), a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra. Although current PD therapies provide symptomatic relief, none halt or reverse disease progression. Early transplantation studies using fetal dopaminergic neurons provided proof of concept for PD cell replacement, with recent efforts focusing on pluripotent stem cell-derived dopaminergic progenitors that are now entering clinical testing. These strategies face challenges, however, including immune compatibility, tumorigenic risk, and the need for controlled differentiation and functional integration. Multi-lineage differentiating stress-enduring (Muse) cells are endogenous, non-tumorigenic pluripotent-like stem cells that home to sites of tissue injury and differentiate in response to the host microenvironment. A targeted literature search of PubMed and Scopus, however, did not identify prior reviews specifically addressing Muse cells in the context of PD, highlighting a gap in the literature. Here, we examine current limitations of established cell-replacement approaches and consider whether Muse cells may represent a mechanistically distinct cell source. Early clinical studies of Muse cell therapy in stroke and amyotrophic lateral sclerosis suggest an encouraging safety profile and preliminary signals of potential therapeutic benefit, although these findings are based on small, early-stage trials and require confirmation. The evidence supporting Muse cell therapy in PD is currently limited to a single preclinical animal study, supported by mechanistic in vitro findings and indirect evidence from other neurologic disease models; therefore, its relevance to PD remains to be established, and current evidence is insufficient to support conclusions regarding clinical efficacy. Together, these observations provide a rationale for further targeted preclinical investigation and support the systematic evaluation of Muse cells as a mechanistically distinct candidate for regenerative therapy in PD. Full article

The pathophysiological basis of Parkinson’s disease (PD) remains incompletely understood. However, the influence of environmental factors, such as continuous cadmium exposure, requires further investigation. Notably, common comorbidities such as iron deficiency anemia (IDA), chronic obstructive pulmonary disease (COPD), and zinc deficiency are linked with increased cadmium bioavailability, and elevated blood cadmium levels have been reported in individuals with PD. Cd (II) deposits in the midbrain, causing the accumulation of inflammatory lipids, which promote neuronal destruction. Cd-treated animals develop Parkinson-like syndromes, and cadmium exposure is associated with neuronal loss and disruption of dopaminergic receptor expression. Neurofilament light chain (NfL), a biomarker of neurodegeneration, has been found to be elevated in patients with Parkinson’s disease and correlates with Cd blood concentrations. Iron deficiency promotes the secretion of FGF-23, which depletes vitamin D levels, further increasing the risk of PD. Moreover, COPD and IDA are two well-known examples of systemic hypoxia, which attracts metals bound to transferrin, such as cadmium and iron, leading to increased metal accumulation in various tissues, including the brain. Lead levels are also elevated in individuals with IDA, contributing to the risk of PD. Additionally, Cd exposure is associated with a reduced abundance of Lachnospiraceae in stool and decreased levels of butyrate, both of which are characteristic features of patients with Parkinson’s disease. Therefore, this review aims to explore how COPD, IDA, and zinc deficiency—known risk factors for Parkinson’s disease—lead to an increased cadmium burden and contribute to the onset and progression of the disease. Full article

The use of substances that modulate mitochondrial dynamics in cells of nervous tissue represents a new direction in targeted therapy for neurodegeneration. The aim of this study was to evaluate the effect of mitochondrial division inhibitor-1 (Mdivi-1) on neurons and microgliocytes of the substantia nigra under conditions of partial damage to the dopaminergic system. This study was conducted using the 6-hydroxydopamine model of parkinsonism in rats; a separate experimental group of animals received Mdivi-1 intraperitoneally at a dose of 20 mg/kg for 5 days. The intensity of immunofluorescence staining for Tomm20, MTCO1, pDrp1, and Mfn2 was evaluated in neurons of the substantia nigra, and microglial activation was morphologically assessed. It was found that unilateral administration of 6-OHDA led to pro-inflammatory changes in microglia and changes in mitochondrial markers of neurons on the side of the substantia nigra contralateral to the toxin injection. Mdivi-1 did not affect the damage and mitochondrial proteins of neurons in pars compacta of the substantia nigra; however, it changed mitochondrial markers in nervous cells of the pars reticulata. The use of Mdivi-1 to address abnormal processes in neurodegeneration requires additional studies that include a differential assessment of its effects on various cell types. Full article

Impairment of axonal transport may contribute to the degeneration of dopaminergic (DAergic) neurons in the substantia nigra (SN), a key event in Parkinson’s disease (PD) pathogenesis. Due to the lack of early diagnosis, changes in axonal transport at the preclinical stage can only be studied in PD models. We assessed gene expression (RT-PCR after cell sorting) and protein levels (semiquantitative immunohistochemistry) of axonal transport-related proteins in SN DAergic neurons from mice in subchronic MPTP models of PD (preclinical and clinical stages) and controls. The proteins studied included α-tubulin (Tuba1a), β-tubulin (Tubb3), kinesin (Kif5b, Klc1), dynein (Dynll1, Dync1i1), dynactin (Dctn1), microtubule affinity-regulating kinase 1 (Mark1), and tau (Mapt). In the preclinical stage, Kif5b expression and Kif5B level were increased, possibly to compensatorily preserve anterograde transport. Dynll1 and Tuba1a were upregulated, whereas Dync1i1 and Mapt were downregulated, with no change in tubulin or tau protein levels. In the clinical stage, Klc1, Dync1i1, Dctn1, Mark1, and Mapt expression and Kif5B protein levels decreased. These data indicate that transcriptional alterations in axonal transport proteins precede protein-level changes in DAergic neurons. The upregulation of Kif5B in the preclinical stage suggests that axonal transport proteins may serve as potential early therapeutic targets in PD. Full article

Environmental exposure to neurotoxicants during critical developmental windows may program long-term susceptibility to neurodegenerative diseases such as Parkinson’s disease. Here, we investigated whether rotenone exposure during neurodevelopment induces a more severe Parkinsonian phenotype during aging than adult-onset exposure. Wistar rats were exposed to rotenone (1 mg/kg/day) either during gestation and lactation or from postnatal day 60 to 102. Motor performance was assessed longitudinally, and neurobiological analyses were conducted at 12 months of age. Developmental rotenone exposure induced persistent and severe motor deficits from early adulthood, whereas adult exposure resulted in a progressive phenotype. These alterations were accompanied by greater loss of tyrosine hydroxylase-positive dopaminergic neurons and a marked reduction in Nurr1 expression in the substantia nigra. Developmental exposure also increased cellular senescence, dendritic atrophy and spine loss in striatal medium spiny neurons, insoluble α-synuclein accumulation, and global DNA hypomethylation. Despite low residual serum rotenone levels, neurodegenerative alterations persisted, supporting a hit-and-run mechanism. These findings suggest that early-life rotenone exposure induces long-lasting epigenetic and cellular reprogramming that enhances nigrostriatal vulnerability and accelerates Parkinsonian neurodegeneration during aging. Full article

Copper (Cu) and perfluorooctanesulfonic acid (PFOS) are ubiquitous environmental pollutants that frequently co-occur, each capable of inducing neurotoxicity individually. However, the combined toxicity and interactive mechanisms of their co-exposure remain unclear, hindering an accurate assessment of their combined environmental health risks. Using the Caenorhabditis elegans model, we investigated the effects of co-exposure to environmentally relevant concentrations. Compared to individual exposures, co-exposure triggered synergistic neurotoxicity, characterized by the loss of dopaminergic (DAergic) and glutamatergic (GLUergic) neurons, aggravated locomotor deficits, massive accumulation of reactive oxygen species (ROS), and a severe decline in mitochondrial membrane potential, accompanied by substantial mitochondrial ultrastructural damage and accumulation of autophagosomes. Mechanistically, the excessive oxidative stress induced by co-exposure aberrantly and persistently activated the ROS-mediated mitophagy pathway, thereby impairing mitochondrial quality control. Critically, intervention with N-acetylcysteine (NAC), an antioxidant, effectively mitigated the co-exposure-induced deficits, identifying oxidative stress as the central driver of the synergistic toxicity. Our findings reveal a novel mechanism by which Cu and PFOS exert synergistic neurotoxicity via the oxidative-stress–mitophagy axis, providing key scientific evidence for refining the assessment of their combined environmental pollution risks. Full article