Palmitoyl Serotonin Inhibits L-dopa-induced Abnormal Involuntary Movements in the Mouse Parkinson Model

The Role of ΔFosB in the Pathogenesis of Levodopa-Induced Dyskinesia: Mechanisms and Therapeutic Strategies

Levodopa-induced dyskinesia (LID) represents a significant complication associated with the long-term administration of levodopa (L-DOPA) for the treatment of Parkinson's disease (PD). This review examines the critical role of ΔFosB, a transcription factor, in the pathogenesis of LID and explores potential therapeutic interventions. ΔFosB accumulates within the striatum in response to chronic dopaminergic stimulation, thereby driving maladaptive changes that culminate in dyskinesia. Its persistent expression modifies gene transcription, influencing neuronal plasticity and contributing to the sustained presence of dyskinetic movements. This study explains how ΔFosB functions at the molecular level, focusing on its connections with dopamine D1 receptors, the cAMP/PKA signaling pathway, and its regulatory effects on downstream targets such as DARPP-32 and GluA1 AMPA receptor subunits. Additionally, it examines how neuronal nitric oxide synthase (nNOS) affects ΔFosB levels and the development of LID. This review also considers the interactions between ΔFosB and other signaling pathways, such as ERK and mTOR, in the context of LID and striatal plasticity. Emerging therapeutic strategies targeting ΔFosB and its associated pathways include pharmacological interventions like ranitidine, 5-hydroxytryptophan, and carnosic acid. Furthermore, this study addresses the role of JunD, another component of the AP-1 transcription factor complex, in the pathogenesis of LID. Understanding the molecular mechanisms by which ΔFosB contributes to LID offers promising avenues for developing novel treatments that could mitigate dyskinesia and improve the quality of life for PD patients undergoing long-term L-DOPA therapy.

Decrease of KATP channel expression through D3 receptor-mediated GSK3β signaling alleviates levodopa-induced dyskinesia (LID) in Parkinson's disease mouse model

AIMS

The standard Parkinson's disease (PD) treatment is L-3,4-dihydroxyphenylalanine (L-DOPA); however, its long-term use may cause L-DOPA-induced dyskinesia (LID). Aberrant activation of medium spiny neurons (MSNs) contributes to LID, and MSN excitability is regulated by dopamine D3 receptor (D3R) and ATP-sensitive potassium (KATP) channel activity. Nevertheless, it remains unclear if D3R and KATP channels may be linked in the context of LID.

METHODS

Wild-type and tyrosine hydroxylase (TH)-specific Kir6.2 knockout mice were injected with 6-hydroxydopamine (6-OHDA) to generate a PD mouse model, then chronically treated with L-DOPA to induce LID. Analyses included immunohistochemical staining, biochemical endpoints, and behavior tests. The mechanisms by which D3R/KATP channels regulate LID in the PD/LID mouse model were probed by treatment with a D3R antagonist, KATP channel opener and glycogen synthase kinase 3β (GSK3β) inhibitor, followed by evaluation of abnormal involuntary movements (AIMs).

KEY FINDINGS

The D3R antagonist FAUC365 alleviated LID, reducing AIMs and protecting against degeneration of the nigrostriatal pathway, which occurred through a direct interaction between D3Rs and KATP channels. In line with this mechanism, activation of D3R/GSK3β signaling increased KATP channel expression in the striatum of PD/LID mice. Additionally, the KATP channel opener Diz slowed LID progression and preserved nigrostriatal projections. Consistently, mice with TH-specific knockout of Kir6.2 exhibited reduced PD-like symptoms and less severe LID.

SIGNIFICANCE

D3Rs act through GSK3β signaling to regulate expression of KATP channels, which may subsequently modulate LID. Inhibition of KATP channels in TH-positive cells is sufficient to reduce AIMs in a mouse model of PD/LID.

A sustainable protocol for the synthesis of N-acyl tryptamines, a class of potential gut microbiota-derived endocannabinoid-like mediators

A simple and sustainable propylphosphonic anhydride (T3P)-assisted methodology for the synthesis of N-acyl tryptamines, an interesting class of gut microbiota-derived endocannabinoid-like lipid mediators, was proposed. This protocol is characterized by great operational simplicity, and all products were obtained at room temperature, without the use of an inert atmosphere and by using limited amounts of non-halogenated solvents. Finally, the possibility to realize the reaction under mechanochemical conditions was explored with interesting results.

Early biomarkers in the presymptomatic phase of cognitive impairment: changes in the endocannabinoidome and serotonergic pathways in Alzheimer's-prone mice after mTBI

BACKGROUND

Despite extensive studies on the neurobiological correlates of traumatic brain injury (TBI), little is known about its molecular determinants on long-term consequences, such as dementia and Alzheimer's disease (AD).

METHODS

Here, we carried out behavioural studies and an extensive biomolecular analysis, including inflammatory cytokines, gene expression and the combination of LC-HRMS and MALDI-MS Imaging to elucidate the targeted metabolomics and lipidomics spatiotemporal alterations of brains from wild-type and APP-SWE mice, a genetic model of AD, at the presymptomatic stage, subjected to mild TBI.

RESULTS

We found that brain injury does not affect cognitive performance in APP-SWE mice. However, we detected an increase of key hallmarks of AD, including Aβ1-42 levels and BACE1 expression, in the cortices of traumatized transgenic mice. Moreover, significant changes in the expanded endocannabinoid (eCB) system, or endocannabinoidome (eCBome), occurred, including increased levels of the endocannabinoid 2-AG in APP-SWE mice in both the cortex and hippocampus, and N-acylserotonins, detected for the first time in the brain. The gene expression of enzymes for the biosynthesis and inactivation of eCBs and eCB-like mediators, and some of their main molecular targets, also underwent significant changes. We also identified the formation of heteromers between cannabinoid 1 (CB1) and serotonergic 2A (5HT2A) receptors, whose levels increased in the cortex of APP-SWE mTBI mice, possibly contributing to the exacerbated pathophysiology of AD induced by the trauma.

CONCLUSIONS

Mild TBI induces biochemical changes in AD genetically predisposed mice and the eCBome may play a role in the pathogenetic link between brain injury and neurodegenerative disorders also by interacting with the serotonergic system.

Comprehensive lipid analysis of green Arabica coffee beans by LC-HRMS/MS

Lipids play an important role in coffee bean development, coffee brew and in the effects of coffee on human health. They account for around 17% of the dry bean weight and encompass different classes and subclasses, mostly triacylglycerols (TAG) and a minor quantity of phospholipids (PL) and ^βN-alkanoyl-5-hydroxytryptamides (C-5HT). To comprehensive profile these different lipids, it is important to evaluate extraction methods that provide high lipid coverage and to analyze the lipids in high-resolution techniques. In this work, liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) was employed to comprehensive profile lipids from green Arabica coffee beans and to evaluate the extraction efficiency and lipid coverage of three methods: Bligh-Dyer (BD), Folch (FO), and Matyash (MA). The MA method yielded the greatest number of annotated compounds (131 lipids) compared to the other methods. In the positive electrospray ionization (ESI) mode, the main difference among extraction methods was observed for TAG and diacylglycerols, whereas for the negative ESI it was observed differences for phosphatidylinositol (PI), lysophosphatidylinositol and phosphatidic acid (p < 0.05). The analysis of coffees from different maturation stages and/or post-harvest processes were also performed using the MA method. Immature beans were discriminated from mature and overripe beans by its lower levels of C-5HT, PI, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, and lysophosphatidylethanolamine. These results can help to better understand the coffee lipid composition and its association with coffee quality.

Anti-α-synuclein ASO delivered to monoamine neurons prevents α-synuclein accumulation in a Parkinson's disease-like mouse model and in monkeys

BACKGROUND

Progressive neuronal death in monoaminergic nuclei and widespread accumulation of α-synuclein are neuropathological hallmarks of Parkinson's disease (PD). Given that α-synuclein may be an early mediator of the pathological cascade that ultimately leads to neurodegeneration, decreased α-synuclein synthesis will abate neurotoxicity if delivered to the key affected neurons.

METHODS

We used a non-viral gene therapy based on a new indatraline-conjugated antisense oligonucleotide (IND-ASO) to disrupt the α-synuclein mRNA transcription selectively in monoamine neurons of a PD-like mouse model and elderly nonhuman primates. Molecular, cell biology, histological, neurochemical and behavioral assays were performed.

FINDINGS

Intracerebroventricular and intranasal IND-ASO administration for four weeks in a mouse model with AAV-mediated wild-type human α-synuclein overexpression in dopamine neurons prevented the synthesis and accumulation of α-synuclein in the connected brain regions, improving dopamine neurotransmission. Likewise, the four-week IND-ASO treatment led to decreased levels of endogenous α-synuclein protein in the midbrain monoamine nuclei of nonhuman primates, which are affected early in PD.

CONCLUSIONS

The inhibition of α-synuclein production in dopamine neurons and its accumulation in cortical/striatal projection areas may alleviate the early deficits of dopamine function, showing the high translational value of antisense oligonucleotides as a disease modifying therapy for PD and related synucleinopathies.

FUNDING

Grants SAF2016-75797-R, RTC-2014-2812-1 and RTC-2015-3309-1, Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (ERDF), UE; Grant ID 9238, Michael J. Fox Foundation; and Centres for Networked Biomedical Research on Mental Health (CIBERSAM), and on Neurodegenerative Diseases (CIBERNED).

Effects of histone acetyltransferase inhibitors on L-DOPA-induced dyskinesia in a murine model of Parkinson's disease

Histone acetylation is a key regulatory factor for gene expression in cells. Modulation of histone acetylation by targeting of histone acetyltransferases (HATs) effectively alters many gene expression profiles and synaptic plasticity in the brain. However, the role of HATs on L-DOPA-induced dyskinesia of Parkinson's disease (PD) has not been reported. Our aim was to determine whether HAT inhibitors such as anacardic acid, garcinol, and curcumin from natural plants reduce severity of L-DOPA-induced dyskinesia using a unilaterally 6-hydroxydopamine (6-OHDA)-lesioned PD mouse model. Anacardic acid 2 mg/kg, garcinol 5 mg/kg, or curcumin 100 mg/kg co-treatment with L-DOPA significantly reduced the axial, limb, and orofacial (ALO) score indicating less dyskinesia with administration of HAT inhibitors in 6-OHDA-lesioned mice. Additionally, L-DOPA's efficacy was not altered by the compounds in the early stage of treatment. The expression levels of c-Fos, Fra-2, and Arc were effectively decreased by administration of HAT inhibitors in the ipsilateral striatum. Our findings indicate that HAT inhibitor co-treatment with L-DOPA may have therapeutic potential for management of L-DOPA-induced dyskinesia in patients with PD.

Effects of blackberry (Morus nigra) fruit juice on levodopa-induced dyskinesia in a mice model of Parkinson's disease

Background and objective

Levodopa-induced dyskinesia (LID) is a movement disorder that occurs due to levodopa consumption for a long period to attenuate Parkinsonism. Plants have been the basis for medical treatments in human history and still widely practiced. Blackberry (Morus nigra) is one of the fruits rich in anthocyanin. The present study examined the effect of blackberry fruit juice on LID in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson’s disease in mice.

Materials and methods

In this study, 42 male mice were used, which were divided into six groups equally: one control group and five groups receiving MPTP injection. After confirmation of Parkinsonism in MPTP groups, one group was preserved without treatment and four other groups were treated with levodopa (50 mg/kg ip). After the onset of LID (2 weeks), one group was kept without additional treatment and three other groups were treated with three different doses of blackberry fruit juice (5, 10, and 15 mL/kg) with levodopa orally for 7 days. Abnormal involuntary movement scale (AIMS) and cylinder behavioral test were carried out according to the schedule. The collected data were analyzed using the SPSS software with the significant level of P<0.05.

Results

Parkinson’s disease was confirmed with AIMS test on the fourth day after MPTP injection. The onset of LID was observed after 2 weeks of levodopa treatment using both behavioral tests. The result of administration of M. nigra fruit juice for 1 week showed that this addition is useful in hindering LID. These effects were more pronounced at doses 10 and 15 mL/kg with nearly the same results on attenuating AIMS. Low dose of the fruit juice does not seem to affect LID significantly.

Conclusion

M. nigra fruit juice is effective to attenuate LID in an MPTP-induced Parkinson mice model.

Simvastatin Inhibits Activation of NADPH Oxidase/p38 MAPK Pathway and Enhances Expression of Antioxidant Protein in Parkinson Disease Models

Evidence suggests that oxidative stress is involved in the pathogenesis of Parkinson disease (PD). Simvastatin has been suggested to protect against oxidative stress in several diseases. However, the molecular mechanisms by which simvastatin protects against neuropathology and oxidative damage in PD are poorly elucidated. In this study, we aimed to investigate the potential neuroprotective effects of simvastatin owing to its anti-oxidative properties in 6-hydroxydopamine (6-OHDA)-treated SH-SY5Y cells and mice. The results of 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence and CCK-8 assay demonstrated that simvastatin reduced intracellular reactive oxygen species (ROS) levels and reversed apoptosis in 6-OHDA-treated SH-SY5Y cells. Mechanistic studies revealed that 6-OHDA-induced activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase/p38 mitogen-activated protein kinase (MAPK) pathway was inhibited and nuclear factor-κB (NF-κB) nuclear transcription decreased in SH-SY5Y cells after simvastatin treatment. Enhanced expression levels of superoxide dismutase (SOD), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and glutamate-cysteine ligase modifier subunit (GCLM) were observed after simvastatin treatment in 6-OHDA-treated SH-SY5Y cells. In vivo studies revealed that administration of simvastatin by gavage decreased limb-use asymmetry and apomorphine-induced rotations in 6-OHDA-lesioned mice. Simvastatin increased dopaminergic neurons and reduced protein tyrosine nitration and gliosis in the midbrain of PD mice. An inhibitory effect on activation of the NADPH oxidase/p38 MAPK was observed, and increased antioxidant protein expression in the midbrain were seen in the simvastatin plus 6-OHDA group compared with the 6-OHDA-lesioned group. Taken together, these results demonstrate that simvastatin might inhibit the activation of NADPH oxidase/p38 MAPK pathway, enhance antioxidant protein expression and protect against oxidative stress, thereby providing a novel antioxidant mechanism that has therapeutic validity.