Search Results (1,126)

Background: Obesity is a complex disorder with both metabolic and neurocognitive consequences, including impairments in prefrontal cortex (PFC)-dependent learning and memory. Combination pharmacotherapy may offer a more effective approach for addressing obesity-induced cognitive deficits. Objective: This study evaluated the effects of 30-day co-administration of lorcaserin (5-HT₂C agonist) and betahistine (H₁ agonist/H₃ antagonist) in reversing cognitive deficits in a diet-induced obesity (DIO) rat model. Methods: Male Lewis rats were subjected to DIO and administered lorcaserin (2 mg/kg) and betahistine (5 mg/kg), either alone or in combination, via intraperitoneally implanted osmotic minipumps for 30 days. Y-maze, novel object recognition, and object-in-place (OIP) tests were used to assess cognitive functions. In vivo electrophysiological recordings were employed to examine effects of the combination treatment on ventral tegmental area (VTA) dopaminergic neuron activity. Results: Obese Western-diet-fed rats showed lower discrimination scores in the OIP task, a behavioral test that engages PFC functions, while their performance in the Y-maze and novel object recognition tasks was similar to that of non-obese Control-diet-fed rats. Combination treatment with lorcaserin and betahistine significantly improved the OIP scores of obese rats. However, the combination treatment did not reduce body weight or obesity-associated morphometrical parameters. Electrophysiological recordings revealed a reduction in the number of spontaneously active dopaminergic neurons in the VTA of obese rats. Lorcaserin and betahistine co-treatment significantly increased the number of spontaneously active dopaminergic neurons of obese animals. Conclusions: These results demonstrate the potential of combination lorcaserin–betahistine treatment to reverse obesity-related cognitive deficits, possibly through enhancement of mesocortical dopaminergic neuron activity. Full article

Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra, and key pathways such as neuroinflammation, oxidative stress, and autophagy are believed to significantly contribute to the mechanisms of neurodegeneration. Calpain activation plays a critical role in neuroinflammation and neurodegeneration, as demonstrated by its impact on microglial activation, reactive oxygen species (ROS) production, and neuronal survival. In this study, we investigated the effects of calpain inhibition using calpeptin (CP) and calpain-2-specific inhibitors in cellular and murine models of neuroinflammation and PD. In BV2 microglial cells, LPS-induced production of pro-inflammatory cytokines (TNF-α, IL-6) and chemokines (MCP-1, IP-10) were significantly reduced by CP treatment with a concomitant decrease in ROS generation. Similarly, in VSC-4.1 motoneuron cells, calpain inhibition attenuated IFN-γ-induced ROS production and improved cell viability, demonstrating its neuroprotective effects. Moreover, in a murine MPTP model of PD, calpain inhibition reduced astrogliosis, ROCK2 expression, and levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-7, and IL12p70) and chemokines (MCP-1 and IP-10) in the dorsal striatum and plasma. The specific role of calpain-2 in immune modulation was further highlighted in human microglia, SV-40 cells. With respect to immune modulation in these cells, siRNA-mediated knockdown of calpain-2, but not calpain-1, significantly reduced antigen presentation to CD4+ T cells. Thus, calpain-2 is likely involved in regulating antigen presentation and activation of inflammatory CD4+ T cells. These findings underscore the therapeutic potential of calpain-2 inhibition in mitigating neuroinflammation and neurodegeneration, particularly in PD, by targeting microglial activation, ROS production, and neuronal survival pathways. Full article

Oxidative stress and mitochondrial dysfunction are heavily implicated in all forms of Parkinson’s disease; however, antioxidant administration has largely failed in clinical trials. Among the likely causes of failure are brain bioavailability and cellular redox state. We have administered two manganese porphyrin compounds with different bioavailability, MnTE-2-PyP⁵⁺ and MnTnBuOE-2-PyP⁵⁺, to parkin-null Drosophila food and found that the more bioavailable one, with higher brain and mitochondrial availability, MnTnBuOE-2-PyP⁵⁺, improves developmental deficits and motivated behavior in female flies. Using highly sensitive redox reporters, we further found that MnTnBuOE-2-PyP⁵⁺ reduces hydrogen peroxide levels in mitochondria of dopaminergic neurons that are functionally homologous to the mammalian substantia nigra and facilitates motivated behavior in female flies. Interestingly, both compounds reduce an oxidative stress marker at the whole-brain level and extend lifespan in control flies. Neither compound improves lifespan in parkin-null flies. Thus, additional studies, changing the timing and/or dosage of compound administration, are warranted. Full article

Background: Dopamine (DA) is a critical neurotransmitter that regulates many physiological and behavioral processes. The central dopaminergic system plays a pivotal role in modulating general anesthesia (GA). DA release in the brain is mainly concentrated in the nucleus accumbens (NAc), prefrontal cortex, hypothalamus, and dorsal striatum. Several NAc neuron subtypes are essential for modulating states of consciousness during GA. However, whether NAc DA signal dynamics correlate with different states of consciousness under sevoflurane anesthesia remains to be elucidated. In this study, we measured the dynamic fluctuations of NAc DA levels throughout sevoflurane anesthesia to verify its role. Methods: An intensity-based genetically encoded DA indicator, dLight1.1, was employed to track DA release in the NAc. Fiber photometry combined with electroencephalogram/electromyogram recordings was employed to synchronously track NAc DA signal dynamics across different states of consciousness under sevoflurane anesthesia. Results: Under 2.5% sevoflurane exposure, DA release in the NAc significantly increased during the initial 100 s of sevoflurane induction, which was designated as sevo on-1 (mean ± standard error of the mean [SEM]; baseline vs. sevo on-1, p = 0.0261), and continued to decrease in the subsequent anesthesia maintenance phases (sevo on-1 vs. sevo on-4, p = 0.0070). Following the cessation of sevoflurane administration (with intervals denoted as sevooff), NAc DA gradually returned to baseline levels (sevo on-1 vs. sevo off-1, p = 0.0096; sevo on-1 vs. sevo off-3, p = 0.0490; sevo on-1 vs. sevo off-4, p = 0.0059; sevo on-4 vs. sevo off-4, p = 0.0340; sevo off-1 vs. sevo off-4, p = 0.0451). During the induction phase, NAc DA signal dynamics markedly increased during the pre-loss of consciousness (LOC) period (pre-anesthesia baseline vs. pre-LOC, p = 0.0329) and significantly declined after LOC (pre-LOC vs. post-LOC, p = 0.0094). For the emergence period, NAc DA release exhibited a noticeable increase during the initial period after recovery of consciousness (ROC) (anesthesia baseline vs. post-ROC, p = 0.0103; pre-ROC vs. post-ROC, p = 0.0086). Furthermore, the DA signals peaked rapidly upon the initiation of the burst wave and then gradually attenuated, indicating a positive correlation with the burst wave onset during burst suppression events. Conclusions: Our findings revealed that NAc DA neurotransmitter signal dynamics correlate with different states of consciousness throughout sevoflurane anesthesia. Full article

Parkinson’s disease (PD) is a common neurodegenerative disorder caused by progressive loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies. While PD is most recognized by its motor symptoms (resting tremor, rigidity, bradykinesia, and postural instability), cognitive decline (CD) may become apparent as PD progresses, leading to Parkinson’s disease dementia (PDD). Type 2 diabetes mellitus (T2DM) and insulin resistance (IR) are risk factors for dementia, especially Alzheimer’s disease; however, their influence on dementia in PD is underexplored. Therefore, we sought to determine the effect of T2DM and IR on dementia in PD. A systematic search of articles from 2005 to March 2025 was undertaken using Embase, PubMed, Scopus, Web of Science, and citation searching. Case–control, cross-sectional, longitudinal, and non-human population studies assessing cognitive outcomes in individuals with PD, with and without T2DM and IR, were included (PROSPERO registration number CRD420251013367). In total, 27 studies met the inclusion criteria, with clinical sample sizes ranging from 23 to 544,162 participants. Among the 23 clinical studies, 15 identified T2DM as a contributor to cognitive decline (CD) in PD, and 4 specifically examined insulin resistance (IR). Elevated HbA1c was consistently associated with poorer cognitive performance and increased risk of Parkinson’s disease dementia (PDD); HbA1c ≥ 7% independently predicted cognitive impairment (OR = 4.25, 95% CI: 1.59–11.34). Vascular and inflammatory markers, including elevated LDL-C, fibrinogen, and hs-CRP, further exacerbated CD. MoCA and MMSE scores were the most common cognitive measures, consistently showing worse outcomes in PD patients with T2DM. Preclinical studies supported these associations, showing that high-fat-diet-induced T2DM and IR aggravated dopaminergic neuronal loss by 38–45%, increased α-synuclein by 35%, and heightened microglial activation, providing mechanistic evidence for the observed clinical associations. This systematic review, the first to examine the impact of T2DM and IRs on the occurrence and advancement of CD in PD patients, demonstrates a possible association between the two. However, these results demonstrate the need for larger sample sizes and the inclusion of additional clinical variables, such as HbA1c levels and pharmacological interventions, providing further information about the link between metabolic dysfunction and CD in PD. To further strengthen this link, longitudinal studies with systematic follow-ups are essential to establish causal links and avoid misdiagnosis in clinical practice. Full article

Pituitary pars intermedia dysfunction (PPID) is a common, slowly progressive, neurodegenerative disorder of the older horse. Oxidative damage to the hypothalamic periventricular neurons results in loss of dopaminergic inhibition of the pars intermedia region of the pituitary gland. Consequently, there is increased production of the pro-opiomelanocortin (POMC)-derived hormones normally produced by this region, as well as initial melanocyte hypertrophy and hyperplasia, followed by adenomatous change. Clinical signs that are highly suggestive of the disease are generalised and regional hypertrichosis and delayed/abnormal coat shedding. Numerous clinical signs provide a moderate clinical suspicion, including hyperhidrosis, abnormal fat distribution/regional adiposity, epaxial muscle atrophy/loss of topline, laminitis, weight loss, recurrent infections, behavioural changes/lethargy, polyuria and polydipsia, a pot-bellied appearance, bulging supraorbital fat pads, reduced wound healing, lordosis and infertility. In all animals, a diagnosis of PPID is made based on the signalment, clinical signs and results of further diagnostic tests, with age being a crucial factor to consider. Currently recommended further diagnostic tests are measurement of basal adrenocorticotrophic hormone (ACTH) concentrations (all year) and evaluation of the ACTH response to thyrotrophin-releasing hormone (TRH) using seasonally adjusted references intervals (non-autumn). Animals should also be tested for insulin dysregulation, as laminitis risk in PPID is associated with hyperinsulinaemia. PPID can be managed but not cured; it is a lifelong condition. The individual clinical signs can be managed, e.g., clipping the excessive haircoat and providing unrestricted access to water for individuals with polydipsia. Alternatively, pharmacological management can be employed, and the dopamine-2 receptor agonist pergolide is licensed/approved for the treatment of equine PPID. This should be prescribed in combination with dietary recommendations based on the body condition score and insulin sensitivity status of the individual animal. Full article

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SN), pathological accumulation of alpha-synuclein, and chronic neuroinflammation. The aim of this study is to evaluate the serum levels of systemic inflammatory markers such as neutrophil–lymphocyte ratio (NLR), neutrophil-HDL ratio (NHR), monocyte-HDL ratio (MHR), platelet–lymphocyte ratio (PLR), IL-6, IGF-1, systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI) in patients with PD, and to analyze the relationship between these markers and the clinical stage of the disease as well as its motor and non-motor symptoms. Methods: Fifty-one patients diagnosed with PD and forty-nine HC matched for age and sex were evaluated prospectively. Results: NLR, NHR, and IGF-1 levels were found to be significantly higher in the PD group compared to the HC group (p < 0.05). There was no significant difference between the two groups in terms of PLR, MHR, SII, and SIRI. No significant relationship was found between the inflammatory markers and disease duration, clinical scales, or symptoms. Conclusions: These findings support the role of systemic inflammation in the pathophysiology of PD. Further multi-center, long-term follow-up studies—including simultaneous measurements of central nervous system inflammation markers—are needed for translation into clinical practice. Full article

Parkinson’s disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra and the presence of α-synuclein-positive inclusions known as Lewy bodies. Synphilin-1 is a protein of unknown function that interacts with α-synuclein and has been shown to exhibit cytoprotective effects in both in vitro and in vivo models. In this study, we investigated whether synphilin-1 is phosphorylated by pathological CDK5 and explored the consequences of this modification. Pathological activation of CDK5 occurs mainly through its association with the calpain-cleaved protein p25. Although CDK5 inhibition protects against neurodegeneration in pharmacological PD models, we now show that p25 levels are increased in PD brains. Furthermore, we demonstrate that CDK5, in conjunction with p25, directly phosphorylates synphilin-1, mainly at serine 566. This phosphorylation reduces synphilin-1′s interaction with SIAH1, leading to reduced ubiquitination and subsequent accumulation. We also observed that CDK5-phosphorylated synphilin-1 exhibits a reduced ability to interact with PINK1 and to promote basal levels of mitophagy. Consistent with these findings, the phosphorylation-mimicking synphilin-1 S566E shows decreased translocation to mitochondria, and synphilin-1 levels are reduced in the mitochondria of PD brains compared to age-matched controls. Finally, synphilin-1 S566E promotes retraction of neuronal processes. Taken together, our results suggest that phosphorylation by CDK5 disrupts synphilin-1′s interactions with its protein partners, rendering it more toxic and impairing its ability to support mitophagy and maintain neuronal process homeostasis. We hypothesize that phosphorylation of synphilin-1 by CDK5 may contribute to the pathogenesis of PD. Full article

Background/Objectives: Parkinson’s disease (PD) is a complex nervous system disorder characterized by the gradual loss of dopaminergic neurons, leading to disturbances in movement, such as resting tremors, rigidity, bradykinesia, or akinesia; postural issues; and freezing (motor block). Due to the limitations and side effects of current pharmacological treatments, there is a growing interest in investigating the therapeutic potential of medicinal plants. Methods: A semi-systematic review was conducted using PubMed, Web of Science, and Scopus as main databases, identifying original research articles, systematic reviews, and relevant preclinical or clinical studies published between January 2000 and December 2024. We selected seven plants primarily for their neuroprotective effects, supported by preclinical and animal data. Only articles in English were included in the study. Results: Seventeen articles were included in the study. The results showed that Curcuma longa, Gastrodia elata blume, Ginkgo biloba, Paeonia alba radix, Pueraria lobata, Scutellaria baicalensis, and Withania somnifera have a neuroprotective role, capable of slowing down the progression of PD with different mechanisms of action, ranging from restorative properties of neurons. Conclusions: Developing new drugs based on the respective herb compounds/extracts and herbal formulas is a promising avenue for complementary therapies for PD. However, further preclinical and clinical studies are required to confirm their safety, efficacy, bioavailability, and dosage. 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

The study objectives were to investigate the role of ferroptosis, the mechanism linking iron accumulation, oxidative stress, and dopaminergic dysfunction, in restless legs syndrome (RLS), and to explore its connection with circadian regulation, a key feature of RLS and a known modulator of ferroptosis. We conducted pathway and gene expression analyses in 17 RLS patients and 39 controls, focusing on pathways related to ferroptosis, oxidative stress, iron metabolism, dopaminergic signaling, circadian rhythms, and immune responses. Enrichment analysis, differential gene expression, and cross-pathway gene overlaps were assessed. Ferroptosis and efferocytosis pathways were significantly upregulated in RLS, while oxidative phosphorylation, phosphatidylinositol signaling, PI3K-Akt, FoxO, and adipocytokine pathways were downregulated. The circadian rhythm pathway was markedly suppressed, with 12 circadian genes downregulated, suggesting that circadian disruption may drive ferroptosis activation. Decreased expression of protective pathways, including antioxidant responses and autophagy, was associated with increased iron accumulation, oxidative stress, and inflammation. Dopaminergic synapse genes were upregulated, possibly as a compensatory response to neuronal damage. Several genes overlapped across ferroptosis, circadian, and dopaminergic pathways, indicating a shared pathogenic mechanism. Our findings support a model in which circadian disruption promotes ferroptosis in RLS, contributing to iron overload, oxidative damage, and dopaminergic dysfunction. This pathogenic cascade may also enhance immune activation and inflammation. Circadian regulation and ferroptosis emerge as promising therapeutic targets in RLS. Further studies in larger cohorts are warranted to validate these mechanistic insights. 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

Organoids allow to model healthy and diseased human tissues. and have applications in developmental biology, drug discovery, and cell therapy. Traditionally cultured in immersion/suspension, organoids face issues like lack of standardization, fusion, hypoxia-induced necrosis, continuous agitation, and high media volume requirements. To address these issues, we developed an air–liquid interface (ALi) technology for culturing organoids, termed AirLiwell. It uses non-adhesive microwells for generating and maintaining individualized organoids on an air–liquid interface. This method ensures high standardization, prevents organoid fusion, eliminates the need for agitation, simplifies media changes, reduces media volume, and is compatible with Good Manufacturing Practices. We compared the ALi method to standard immersion culture for midbrain organoids, detailing the process from human pluripotent stem cell (hPSC) culture to organoid maturation and analysis. Air–liquid interface organoids (3D-ALi) showed optimized size and shape standardization. RNA sequencing and immunostaining confirmed neural/dopaminergic specification. Single-cell RNA sequencing revealed that immersion organoids (3D-i) contained 16% fibroblast-like, 23% myeloid-like, and 61% neural cells (49% neurons), whereas 3D-ALi organoids comprised 99% neural cells (86% neurons). Functionally, 3D-ALi organoids showed a striking electrophysiological synchronization, unlike the heterogeneous activity of 3D-i organoids. This standardized organoid platform improves reproducibility and scalability, demonstrated here with midbrain organoids. The use of midbrain organoids is particularly relevant for neuroscience and neurodegenerative diseases, such as Parkinson’s disease, due to their high incidence, opening new perspectives in disease modeling and cell therapy. In addition to hPSC-derived organoids, the method’s versatility extends to cancer organoids and 3D cultures from primary human cells. Full article

Sodium p-perfluorous nonenoxybenzenesulfonate (OBS) has been proposed as a substitute for perfluorooctanesulfonic acid (PFOS), yet it has garnered increasing attention due to its environmental persistence and potential toxicity. Despite these concerns, the neurotoxic mechanisms of OBS remain unclear. This study investigates and compares the neurotoxic effects and mechanisms of OBS and PFOS in Caenorhabditis elegans. L4-stage worms were exposed to OBS (0.1–100 μM) or PFOS (100 μM) for 24 h. Neurobehavioral analysis showed that OBS exposure induced concentration-dependent neurobehavioral deficits, with 100 μM OBS significantly reducing pharyngeal pumping rate (29.8%), head swing frequency (23.4%), and body bending frequency (46.6%), surpassing the effects of PFOS. Both compounds decreased the fluorescence intensity of dopaminergic, glutamatergic, and γ-aminobutyric acid neurons and downregulated neurotransmitter-associated genes. They also increased ROS generation and inhibited antioxidant gene expression. Molecular docking revealed that OBS had a stronger binding affinity to p38 MAPK key protein (PMK-1) than PFOS. OBS and PFOS upregulated pmk-1 and skn-1, modulating oxidative stress and neuronal function. pmk-1 mutation differentially affected OBS-induced neurobehavioral changes and gene expression alterations. Our findings indicate that OBS exhibits stronger neurotoxicity than PFOS in Caenorhabditis elegans, mediated through the PMK-1 pathway. These results highlight the need for further investigation into the safety of OBS as a PFOS alternative. 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