Search Results (257)

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disorder characterized by progressive demyelination and axonal degeneration within the central nervous system, driven by complex genomic and epigenomic dysregulation. Its pathogenesis involves aberrant DNA methylation patterns at CpG islands of numbers of genes like OLIG1 and OLIG2 disrupting protein expression at myelin with compromised oligodendrocyte differentiation. Furthermore, histone modifications, particularly H3K4me3 and H3K27ac, alter the promoter regions of genes responsible for myelination, affecting myelin synthesis. MS exhibits chromosomal instability and copy number variations in immune-regulatory gene loci, contributing to the elevated expression of genes for pro-inflammatory cytokines (TNF-α, IL-6) and reductions in anti-inflammatory molecules (IL-10, TGF-β1). Vitamin D deficiency correlates with compromised immune regulation through hypermethylation and reduced chromatin accessibility of vitamin D receptor (VDR) dysfunction and is reported to be associated with dopaminergic neuronal loss. Vitamin D supplementation demonstrates therapeutic potential through binding with VDR, which facilitates nuclear translocation and subsequent transcriptional activation of target genes via vitamin D response elements (VDREs), resulting in suppression of NF-κB signalling, enhancement of regulatory T-cell (T_reg) responses due to upregulation of specific genes like FOXP3, downregulation of pro-inflammatory pathways, and potential restoration of the chromatin accessibility of oligodendrocyte-specific gene promoters, which normalizes oligodendrocyte activity. Identification of differentially methylated regions (DMRs) and differentially expressed genes (DEGs) that are in proximity to VDR-mediated gene regulation supports vitamin D supplementation as a promising, economically viable, and sustainable therapeutic strategy for MS. This systematic review integrates clinical evidence and eventual bioinformatical meta-analyses that reference transcriptome and methylome profiling and identify prospective molecular targets that represent potential genetic and epigenetic biomarkers for personalized therapeutic intervention. Full article

Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopaminergic neurons (DNs) and movement disorders. Low efficiency of pharmacotherapy requires improvement, e.g., using receptor agonists or antagonists as drugs. Our work aims to initiate these developments by studying the expression levels of genes encoding neurotransmitters, neuropeptides and hormone receptors in substantia nigra pars compacta (SNpc) cells and in isolated DNs in intact mice, and changes in expression of these genes in MPTP mouse models of PD at preclinical and clinical stages. Expression of all 12 studied genes was detected in the SNpc and only 10 in DNs—Cckar and Glp1r were undetectable. In intact mice, the expression of Drd2, Grin2b, Grm1 and Ntsr2 predominates in SNpc tissue, whereas that of Gria2, Chrnb2, Gper1, Igf1r is higher in DNs. In PD models, change in receptor gene expression was detected in DNs but not in SNpc tissue. In the preclinical PD, Drd2 expression increased and Gria2 decreased, whereas in a clinical model, Drd2, Grm1, Ntsr2 expression decreased. Thus, the above genes are expressed in DNs and other cells of SNpc; expression of some genes changes in PD models, which opens up prospects for development of therapy using receptor agonists and antagonists. Full article

Parkinson’s Disease (PD) is the fastest-growing neurological disorder, characterized by the degeneration of dopaminergic neurons. Treatments remain symptomatic, and objective biomarkers for therapeutic response are lacking. This review aims to evaluate the potential of Proton Magnetic Resonance Spectroscopy (¹H-MRS) to provide objective and reproducible biomarkers for monitoring treatment response in PD. This systematic review followed PRISMA guidelines. Articles were searched in PubMed, Web of Science, Scopus, and Embase, and studies employing ¹H-MRS to evaluate pharmacological treatments in PD were included, analyzing pre- and post-treatment changes. Six studies were included, investigating cannabinoids, dopamine agonists, monoamine oxidase B inhibitors, and levodopa. Key metabolites analyzed were N-acetylaspartate, Creatine, Choline, myo-Inositol, and Glx (glutamate+glutamine). Increases in NAA, a marker of neuronal integrity and mitochondrial function, suggested neuroprotective mechanisms of dopaminergic drugs, while stable Cho and mI levels, markers of membrane metabolism and inflammatory processes, suggested limited short-term responsiveness. This is the first systematic review evaluating ¹H-MRS for monitoring neurometabolic changes induced by pharmacological treatments in PD. Observed metabolite changes appear to reflect treatment mechanisms and potential neuroprotective properties. Findings suggest that ¹H-MRS may serve as an objective biomarker for assessing therapeutic efficacy and potential neuroprotective drug effects, although further studies are needed to confirm its clinical utility. Full article

Dopamine (DA) replacement by L-DOPA administration is the most common and effective treatment for Parkinson’s disease (PD). However, its chronic use leads to important side effects at advanced stages of the disease. Levodopa-induced dyskinesia (LID), characterized by involuntary, abnormal movements, is the main challenge of L-DOPA treatment. Although the causes underlying LID are not fully understood, abnormal plasticity in corticostriatal synapses and dysregulated DA release from serotonin terminals play a crucial role. In recent years, several studies have suggested the involvement of neuroinflammation and oxidative stress in the pathophysiology of LID. Interestingly, different evidence has shown that blocking these pathways reduces LID in experimental animal PD models, pointing to the use of antioxidant/anti-inflammatory agents as a potential therapy for LID. Numerous studies have shown the role of the brain renin–angiotensin system (RAS) and the ROCK pathway in neuroinflammation and oxidative stress. Compounds acting through these routes have strong neuroprotective properties in PD models. Additionally, the use of ROCK inhibitors, such as fasudil, and RAS blockers has shown potent anti-dyskinetic effects. Therefore, compounds acting on the RAS and ROCK pathways could have a dual role, slowing down the degeneration of dopaminergic neurons and reducing the development of LID. Full article

Background/Objectives: Glutamatergic neurotransmission is essential for the normal functioning of the retina. Photoreceptor to bipolar and bipolar to ganglion cell signaling is mediated by L-glutamate, which is stored in and released from vesicular glutamate transporter 1 (VGLUT1) containing synaptic vesicles. VGLUT1 is expressed postnatally, P2 onwards, and is required for the glutamatergic retinal wave observed between P10 and P12 in the developing mouse retina. P9–P13 postnatal age is critical for retinal development as VGLUT1 expressing ribbon synapses activate in the outer and inner plexiform layers, and rod/cone mediated visual signaling commences in that period. Although it has been hypothesized that glutamatergic extrinsic signaling drives cell cycle exit and initiates cellular differentiation in the developing retina, it is not clear whether intracellular, synaptic, or extrasynaptic vesicular glutamate release contributes to this process. Recent studies have attempted to decipher VGLUT’s role in retinal development. Here, we investigate the potential effect of genetic loss of VGLUT1 on early postnatal histogenesis and development of retinal neural circuitry. Methods: We employed immunohistochemistry and electrophysiology to ascertain the density of glutamatergic, cholinergic, and dopaminergic cells, spontaneous retinal activity, and light responses in VGLUT1 null retina, and contrasted them with wildtype (WT) and melanopsin null retina. Results: We have demonstrated here that VGLUT1 null retina shows signs of age dependent retinal degeneration, similar to other transgenic mice models with dysfunctional photoreceptor to bipolar cell synapses. The loss of VGLUT1 specifically alters glutamatergic cell density and morphological maturation of retinal ganglion cells. Moreover, VGLUT2 expression is lost in the majority of VGLUT2 cones in the absence of VGLUT1 coexpression, except when VGLUT2 coexpresses transiently with VGLUT3 in these cones, or when VGLUT1 null mice are dark reared. Conclusions: We present the first evidence that synaptic or extrasynaptic postnatal glutamate release from VGLUT1 containing vesicles impacts histogenesis of glutamatergic cells, pruning of retinal ganglion cell dendrites and VGLUT2 expression in cones. Full article

Dithiocarbamate fungicides, including benomyl (methyl 1-butylcarbamoyl-2-benzimidazolecarbamate), share a common mechanism of toxicity by inhibiting aldehyde dehydrogenases (ALDHs), enzymes essential for detoxifying reactive aldehydes. One such aldehyde, 3,4-dihydroxyphenylacetaldehyde (DOPAL), a dopamine metabolite, is implicated in the catecholaldehyde hypothesis of Parkinson’s disease. This study examines ALDH inhibition as the molecular initiating event (MIE) within an adverse outcome pathway (AOP) leading to neurotoxicity. Caenorhabditis elegans at the L4 stage were exposed for 24 h to 10 or 100 μM benomyl. While 10 μM had no significant effect on lethality, growth, or reproduction, 100 μM induced adverse effects, albeit with low lethality. Both doses inhibited ALH activity, an effect mitigated by Alda-1, a selective ALDH activator. Alda-1 alone increased ALH-1 protein levels but did not alter benomyl-induced protein localization and relative abundance. Benomyl exposure also elevated oxidative stress markers—superoxide dismutase, catalase, and lipid peroxidation—which Alda-1 reduced. Neurotoxicity was evidenced by dopaminergic dysfunction, including impaired basal slowing response, neuronal morphological abnormalities, and reduced locomotion upon optogenetic activation. Fluorescent reporter assays confirmed ALH-1 presence in dopaminergic neurons. These results identify ALH inhibition as the MIE in benomyl-induced neurotoxicity, linking dopaminergic degeneration and redox imbalance to the catecholaldehyde hypothesis, and providing mechanistic insights into an AOP relevant to neurodegenerative disorders. Full article

Background/Objectives: Parkinson’s disease (PD) is the second-most prevalent neurodegenerative disorder, characterized by the progressive loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc). Experimental models that replicate core features of PD are critical to investigate underlying mechanisms and therapeutic strategies. Here we evaluated the effects of an acute unilateral intrastriatal lesion induced by 6-hydroxydopamine (6-OHDA) on neuronal loss and the associated inflammatory response. Methods: Adult male Wistar rats received an injection of 6-OHDA into the right striatum, while the contralateral side received vehicle. Motor behavior was assessed by cylinder and open field tests on post-lesion days (PLDs) 7 and 14. Brains were analyzed by immunohistochemistry for tyrosine hydroxylase (TH), glial response (GFAP and Iba1), and caspase-3 at PLD +14. Results: A marked reduction in TH-immunoreactivity in the lesioned striatum was observed, with ~40% loss of TH-positive neurons in the ipsilateral SNpc. Surviving neurons displayed a 28% increase in soma size compared to the contralateral side. The lesion was accompanied by robust astrocytic and microglial activation at the injection site, as well as enhanced GFAP immunoreactivity in the ipsilateral SN pars reticulata. Apoptotic profiles emerged in the SNpc at PLD +14. Functionally, these alterations were reflected in significant motor asymmetry and decreased locomotor activity. Conclusions: Our findings demonstrate that neuroinflammation accompanies early dopaminergic degeneration following intrastriatal 6-OHDA administration, contributing to motor deficits. Future studies with older animals and broader behavioral and anatomical assessments—including regions such as the ventral tegmental area and motivational or anxiety-related paradigms—may enhance translational relevance. Full article

Parkinson’s disease is a neurodegenerative disorder characterized by the degeneration of dopaminergic neurons, resulting in multiple motor and cognitive impairments. Among the hypotheses proposed for its etiology, oxidative stress mediated by the enzyme monoamine oxidase B (MAO-B) stands out, as it is directly associated with dopamine metabolism. In this context, the search for molecules with potential antiparkinsonian activity and low toxicity, particularly those of natural origin, has been extensively investigated using computational approaches. In the present study, a pharmacophore-based virtual screening was carried out on molecules belonging to the alkaloid and flavonoid groups, followed by the evaluation of their pharmacokinetic, toxicological, and biological activity profiles, as well as ligand–receptor interaction analysis through molecular docking. The results indicated that palmatine, genistein, ZINC00597214, and ZINC72342127 exhibited superior performance compared to the other analyzed structures, considering all evaluated criteria. Therefore, this study, through in silico methodologies, demonstrated the antiparkinsonian potential of several chemical structures, attributable to their inhibitory activity on the MAO-B enzyme. Further experimental investigations, both in vitro and in vivo, are necessary to more comprehensively characterize the properties of these molecules, with the ultimate goal of developing new therapeutic strategies for the treatment of Parkinson’s disease. Full article

Chronic neuroinflammation plays a crucial role in the progression of neurodegenerative diseases (NDs), including Parkinson’s disease (PD) and Alzheimer’s disease (AD). Leucine-Rich Repeat Kinase 2 (LRRK2), a gene linked to familial and sporadic PD, has been positively associated with neuroinflammation in both in vitro and in vivo systems. These observations suggest that LRRK2 might actively contribute to neuronal damage and degeneration in NDs. Based on these premises, we explored the impact of LRRK2-mediated neuroinflammation on neurons in a PD- and AD-related context. We set up a cellular model composed of human induced pluripotent stem cell (hiPSC)-derived neurons (dopaminergic for PD and cholinergic for AD) exposed to inflamed glial medium [α-synuclein pre-formed fibrils (α-syn pffs) for PD and amyloid-β (Aβ)_1–42 fibrils for AD] for several days. To dissect the effect of neuroinflammation, and specifically, the role of LRRK2, on neuronal functions, we first performed transcriptome analysis, and then, we validated the results at functional levels. Interestingly, we found that LRRK2-dependent neuroinflammation contributes to neuronal dysfunctions and death in both ND contexts and that LRRK2 kinase inhibition prevents these detrimental effects. Overall, our results suggest that lowering neuroinflammation through LRRK2 pharmacological inhibition might limit the progression of NDs and thus be neuroprotective. Full article

Selective proteasome inhibitors, used to model Parkinsonian-like pathology, are known to disrupt calcium homeostasis, but the role of calcium ions in dopaminergic neuron degeneration remains unclear. The present in vivo study examined the effects of a 7-day intraperitoneal administration of cinnarizine (10 or 30 mg/kg), a voltage-gated calcium channel blocker, in rats unilaterally injected into the substantia nigra compacta (SNc) with lactacystin (Lac; 1 µg/2 µL) or vehicle. Dopamine (DA) and its metabolites were quantified in striatal homogenates via high-performance liquid chromatography. The SN of rats treated with 10 mg/kg cinnarizine was used for Western blot analysis of tyrosine hydroxylase (TH), while tissue from animals receiving 30 mg/kg was processed for histological analysis of TH-immunoreactive (TH-ir) and cresyl violet (CV)-stained neurons. Significant reductions in striatal DA and its metabolites were observed one week after Lac injection, along with increased DA catabolism. Cinnarizine at both doses partially prevented DA loss and attenuated enhanced DA turnover. Moreover, 10 mg/kg cinnarizine partially preserved TH protein levels, while 30 mg/kg provided histological protection of TH-ir neurons in the SN. Cinnarizine was also tested in vitro in human SH-SY5Y neuroblastoma cells and primary mouse cortical neurons exposed to Lac or rotenone to further assess its neuroprotective potential. In SH-SY5Y cells, cinnarizine (1–10 µM) significantly increased cell viability and reduced lactate dehydrogenase release after toxin exposure. Cinnarizine failed to counteract lactacystin-induced toxicity in primary cortical neurons but markedly reduced rotenone-evoked cell death at similar concentrations. These findings indicate that cinnarizine exerts dose-dependent neuroprotective effects in vivo and selective protective actions in vitro, supporting the potential utility of voltage-gated calcium channel blockers in treating Parkinson’s disease. Full article

The aggregation of α-synuclein (αSyn) is a central feature of Parkinson’s disease (PD) and other synucleinopathies. The efficient clearance of αSyn depends largely on the autophagy–lysosomal pathway. Emerging genetic evidence highlights the role of pleckstrin homology and RUN domain-containing M1 protein (PLEKHM1), a critical regulator of autophagosome–lysosome fusion, in the pathogenesis of multiple neurodegenerative diseases. This study investigates the possible effects of increased PLEKHM1 expression on αSyn pathology and neurodegeneration in mice. We utilized a mouse model of PD that is based on A53T-αSyn overexpression, achieved by the stereotactic injection of recombinant adeno-associated viral vectors (rAAV) into the substantia nigra. Additionally, this study explores the effect of PLEKHM1 overexpression on the autophagy–lysosomal pathway under physiological conditions, using transgenic autophagy reporter mice. PLEKHM1 overexpression facilitated the αSyn-induced degeneration of dopaminergic somata in the substantia nigra and degeneration of dopaminergic axon terminals in the striatum. In concert with αSyn expression, PLEKHM1 also potentiated microglial activation. The extent of αSyn pathology, as reported by staining for phosphorylated αSyn, was not affected by PLEKHM1. Using RFP-EGFP-LC3 autophagy reporter mice, rAAV-mediated PLEKHM1 overexpression reduced lysosomal and autolysosomal area, increased LAMP1-LC3 colocalization, and decreased the autolysosome-to-autophagosome ratio. Concurrently, PLEKHM1 overexpression in both genotypes caused p62 accumulation, accompanied by reduced overlap with lysosomal and autophagosomal markers but increased colocalization with autolysosomal markers, indicating impaired cargo degradation during late-stage autophagy. Taken together, elevated PLEKHM1 levels exacerbate neurodegeneration in αSyn-overexpressing mice, possibly by impairing autophagic flux. Now, with in vivo evidence complementing genetic data, alterations in PLEKHM1 expression appear to compromise autophagy, potentially enhancing neuronal vulnerability to secondary insults like αSyn pathology. Full article

Background: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons in the substantia nigra (SN), leading to motor impairments and numerous non-motor manifestations, including anxiety. Notably, anxiety has been shown to exacerbate disease progression and hinder treatment outcomes in PD. Botulinum neurotoxin (BoNT), recognized for its ability to block excessive release of acetylcholine (ACh), has been shown to provide clinical effectiveness in managing motor symptoms. BoNT appears to enhance neuroregenerative plasticity and mitigate neuroinflammation through mechanisms speculated to extend beyond its classical mode of action. Nevertheless, reports on its potential anxiolytic and neuroprotective effects in PD remain limited. Aim: This study investigated the effect of BoNT on motor and anxiety-like behaviors in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Methods: The experimental animals were assessed for behavioral changes using the open field test (OFT), rotarod, pole test, light-dark box test (LDBT), and elevated plus maze (EPM). Immunohistochemistry was employed to enumerate tyrosine hydroxylase (TH)-positive dopaminergic neurons and ionized calcium-binding adapter molecule (Iba)-1 expressing microglia in SN. Results: BoNT treatment markedly alleviated motor deficits and anxiety. Quantification of TH- and Iba-1-positive cells revealed that BoNT promotes neuroprotection and minimizes microglial burden in the SN of the PD model. Conclusions: The outcome of the study represents the anxiolytic, neuroprotective, and microglial modulatory potentials of BoNT in PD, supporting its therapeutic promise beyond the management of motor symptoms. Given its multifaceted properties, BoNT can be considered a potential therapeutic candidate for PD and other neurological disorders. Full article

Sleep is a vital biological function governed by neuronal networks in the brainstem, hypothalamus, and thalamus. Disruptions in these circuits contribute to the sleep disturbances observed in neurodegenerative disorders, including Parkinson’s disease, epilepsy, Huntington’s disease, and Alzheimer’s disease. Oxidative stress, mitochondrial dysfunction, neuroinflammation, and abnormal protein accumulation adversely affect sleep architecture in these conditions. The interaction among these pathological processes is believed to modify sleep-regulating circuits, consequently worsening clinical symptoms. This review examines the cellular and molecular mechanisms that impair sleep regulation in experimental models of these four disorders, emphasizing how oxidative stress, neuroinflammation and synaptic dysfunction contribute to sleep fragmentation and alterations in rapid eye movement (REM) sleep and slow-wave sleep (SWS) phases. In Parkinson’s disease models (6-OHDA and MPTP), dopaminergic degeneration and damage to sleep-regulating nuclei result in daytime somnolence and disrupted sleep patterns. Epilepsy models (kainate, pentylenetetrazole, and kindling) provoke hyperexcitability and oxidative damage, compromising both REM and SWS. Huntington’s disease models (R6/2 and 3-NP) demonstrate reduced sleep duration, circadian irregularities, and oxidative damage in the hypothalamus and suprachiasmatic nucleus. In Alzheimer’s disease (AD) models (APP/PS1, 3xTg-AD, and Tg2576), early sleep problems include diminished SWS and REM sleep, increased awakenings, and circadian rhythm disruption. These changes correlate with β-amyloid and tau deposition, glial activation, chronic inflammation, and mitochondrial damage in the hypothalamus, hippocampus, and prefrontal cortex. Sleep disturbances across these neurodegenerative disease models share common underlying mechanisms like oxidative stress, neuroinflammation, and mitochondrial dysfunction. Understanding these pathways may reveal therapeutic targets to improve both motor symptoms and sleep quality in neurodegenerative disorders. Full article

Parkinson’s disease (PD) is a progressive, multisystemic α-synucleinopathy, recognized as the second most prevalent neurodegenerative disorder globally. Its neuropathology is characterized by the degeneration of dopaminergic neurons, particularly in the substantia nigra pars compacta (SNpc), and the intraneuronal accumulation of α-synuclein-forming Lewy bodies. Oxidative stress is a key contributor to PD pathogenesis. Thioredoxin-interacting protein (TXNIP) is a crucial regulator of cellular redox balance, inhibiting the antioxidant function of thioredoxin. This pilot study aimed to investigate the protein expression and localization of TXNIP in the SNpc of PD patients compared to healthy controls. We performed immunohistochemical analyses on 12 post-mortem human brain sections (formalin-fixed, paraffin-embedded) from six subjects with PD and six healthy controls. The study was performed on PD subjects with Braak stage 6. Our findings revealed that in control samples, TXNIP protein was distinctly and closely associated with neuromelanin (NM) pigment within the cytoplasm of SNpc dopaminergic neurons. Conversely, in PD samples, there was a markedly weak cytoplasmic expression of TXNIP, and critically, this association with NM pigment was absent. Furthermore, PD samples exhibited a significant reduction in both dopaminergic neurons and NM content, consistent with advanced disease. These findings, which mirror previous transcriptomic data showing TXNIP gene under-expression in the same subjects, suggest that altered TXNIP expression and localization in SNpc dopaminergic neurons are features of late-stage PD, potentially reflecting neuronal dysfunction and loss. Full article

Allicin (ALC), a naturally occurring organosulfur compound derived from garlic (Allium sativum), exhibits potential neuroprotective properties. Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by degeneration of dopaminergic neurons and motor dysfunction. This study utilized bioinformatics and network pharmacology methods to predict the anti-PD mechanism of ALC and established in vivo and in vitro PD models using 6-hydroxydopamine (6-OHDA) for experimental verification. Network pharmacological analysis indicates that apoptosis regulation and the PKA/p-CREB/BDNF signaling pathway are closely related to the anti-PD effect of ALC, and protein kinase A (PKA) and dopamine transporter (DAT) are key molecular targets. The experimental results show that ALC administration can alleviate the cytotoxicity of SH-SY5Y induced by 6-OHDA and simultaneously improve the motor dysfunction and dopaminergic neuron loss in PD mice. In addition, ALC can also activate the PKA/p-CREB/BDNF signaling pathway and increase the DAT level in brain tissue, regulate the expression of BAX and Bcl-2, and reduce neuronal apoptosis. These results indicate that ALC can exert anti-PD effects by up-regulating the PKA/p-CREB/BDNF/DAT signaling pathway and inhibiting neuronal apoptosis, providing theoretical support for the application of ALC in PD. Full article