Why do we need multifunctional neuroprotective and neurorestorative drugs for Parkinson's and Alzheimer's diseases as disease modifying agents

New Pieces for an Old Puzzle: Approaching Parkinson's Disease from Translatable Animal Models, Gut Microbiota Modulation, and Lipidomics

Parkinson's disease (PD) is a severe neurodegenerative disease characterized by disabling motor alterations that are diagnosed at a relatively late stage in its development, and non-motor symptoms, including those affecting the gastrointestinal tract (mainly constipation), which start much earlier than the motor symptoms. Remarkably, current treatments only reduce motor symptoms, not without important drawbacks (relatively low efficiency and impactful side effects). Thus, new approaches are needed to halt PD progression and, possibly, to prevent its development, including new therapeutic strategies that target PD etiopathogeny and new biomarkers. Our aim was to review some of these new approaches. Although PD is complex and heterogeneous, compelling evidence suggests it might have a gastrointestinal origin, at least in a significant number of patients, and findings in recently developed animal models strongly support this hypothesis. Furthermore, the modulation of the gut microbiome, mainly through probiotics, is being tested to improve motor and non-motor symptoms and even to prevent PD. Finally, lipidomics has emerged as a useful tool to identify lipid biomarkers that may help analyze PD progression and treatment efficacy in a personalized manner, although, as of today, it has only scarcely been applied to monitor gut motility, dysbiosis, and probiotic effects in PD. Altogether, these new pieces should be helpful in solving the old puzzle of PD.

Relevance of Biochemical Deep Phenotyping for a Personalised Approach to Parkinson's Disease

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder characterised by the progressive loss of dopaminergic neurons in the nigrostriatal tract. The identification of disease-modifying therapies is the Holy Grail of PD research, but to date no drug has been approved as such a therapy. A possible reason is the remarkable phenotypic heterogeneity of PD patients, which can generate confusion in the interpretation of results or even mask the efficacy of a therapeutic intervention. This heterogeneity should be taken into account in clinical trials, stratifying patients by their expected response to drugs designed to engage selected molecular targets. In this setting, stratification methods (clinical and genetic) should be supported by biochemical phenotyping of PD patients, in line with the deep phenotyping concept. Collection, from single patients, of a range of biological samples would streamline the generation of these profiles. Several studies have proposed biochemical characterisations of patient cohorts based on analysis of blood, cerebrospinal fluid, urine, stool, saliva and skin biopsy samples, with extracellular vesicles attracting increasing interest as a source of biomarkers. In this review we report and critically discuss major studies that used a biochemical approach to stratify their PD cohorts. The analyte most studied is α-synuclein, while other studies have focused on neurofilament light chain, lysosomal proteins, inflammasome-related proteins, LRRK2 and the urinary proteome. At present, stratification of PD patients, while promising, is still a nascent approach. Deep phenotyping of patients will allow clinical researchers to identify homogeneous subgroups for the investigation of tailored disease-modifying therapies, enhancing the chances of therapeutic success.

Brain-protective mechanisms of autophagy associated circRNAs: Kick starting self-cleaning mode in brain cells via circRNAs as a potential therapeutic approach for neurodegenerative diseases

Altered autophagy is a hallmark of neurodegeneration but how autophagy is regulated in the brain and dysfunctional autophagy leads to neuronal death has remained cryptic. Being a key cellular waste-recycling and housekeeping system, autophagy is implicated in a range of brain disorders and altering autophagy flux could be an effective therapeutic strategy and has the potential for clinical applications down the road. Tight regulation of proteins and organelles in order to meet the needs of complex neuronal physiology suggests that there is distinct regulatory pattern of neuronal autophagy as compared to non-neuronal cells and nervous system might have its own separate regulator of autophagy. Evidence has shown that circRNAs participates in the biological processes of autophagosome assembly. The regulatory networks between circRNAs, autophagy, and neurodegeneration remains unknown and warrants further investigation. Understanding the interplay between autophagy, circRNAs and neurodegeneration requires a knowledge of the multiple steps and regulatory interactions involved in the autophagy pathway which might provide a valuable resource for the diagnosis and therapy of neurodegenerative diseases. In this review, we aimed to summarize the latest studies on the role of brain-protective mechanisms of autophagy associated circRNAs in neurodegenerative diseases (including Alzheimer's disease, Parkinson's disease, Huntington's disease, Spinal Muscular Atrophy, Amyotrophic Lateral Sclerosis, and Friedreich's ataxia) and how this knowledge can be leveraged for the development of novel therapeutics against them. Autophagy stimulation might be potential one-size-fits-all therapy for neurodegenerative disease as per considerable body of evidence, therefore future research on brain-protective mechanisms of autophagy associated circRNAs will illuminate an important feature of nervous system biology and will open the door to new approaches for treating neurodegenerative diseases.

Exploring links between 2-oxoglutarate-dependent oxygenases and Alzheimer's disease

Hypoxia, that is, an inadequate oxygen supply, is linked to neurodegeneration and patients with cardiovascular disease are prone to Alzheimer's disease (AD). 2-Oxoglutarate and ferrous iron-dependent oxygenases (2OGDD) play a key role in the regulation of oxygen homeostasis by acting as hypoxia sensors. 2OGDD also have roles in collagen biosynthesis, lipid metabolism, nucleic acid repair, and the regulation of transcription and translation. Many biological processes in which the >60 human 2OGDD are involved are altered in AD patient brains, raising the question as to whether 2OGDD are involved in the transition from normal aging to AD. Here we give an overview of human 2OGDD and critically discuss their potential roles in AD, highlighting possible relationships with synapse dysfunction/loss. 2OGDD may regulate neuronal/glial differentiation through enzyme activity-dependent mechanisms and modulation of their activity has potential to protect against synapse loss. Work linking 2OGDD and AD is at an early stage, especially from a therapeutic perspective; we suggest integrated pathology and in vitro discovery research to explore their roles in AD is merited. We hope to help enable long-term research on the roles of 2OGDD and, more generally, oxygen/hypoxia in AD. We also suggest shorter term empirically guided clinical studies concerning the exploration of 2OGDD/oxygen modulators to help maintain synaptic viability are of interest for AD treatment.

In Vitro and In Silico Characterization of Kurarinone as a Dopamine D1A Receptor Antagonist and D2L and D4 Receptor Agonist

Alterations in the expression and/or activity of brain G-protein-coupled receptors (GPCRs) such as dopamine D₁R, D_2LR, D₃R, and D₄R, vasopressin V_1AR, and serotonin 5-HT_1AR are noted in various neurodegenerative diseases (NDDs). Since studies have indicated that flavonoids can target brain GPCRs and provide neuroprotection via inhibition of monoamine oxidases (hMAOs), our study explored the functional role of kurarinone, an abundant lavandulated flavonoid in Sophora flavescens, on dopamine receptor subtypes, V_1AR, 5-HT_1AR, and hMAOs. Radioligand binding assays revealed considerable binding of kurarinone on D₁R, D_2LR, and D₄R. Functional GPCR assays unfolded the compound's antagonist behavior on D₁R (IC₅₀ 42.1 ± 0.35 μM) and agonist effect on D_2LR and D₄R (EC₅₀ 22.4 ± 3.46 and 71.3 ± 4.94 μM, respectively). Kurarinone was found to inhibit hMAO isoenzymes in a modest and nonspecific manner. Molecular docking displayed low binding energies during the intermolecular interactions of kurarinone with the key residues of the deep orthosteric binding pocket and the extracellular loops of D₁R, D_2LR, and D₄R, validating substantial binding affinities to these prime targets. With appreciable D_2LR and D₄R agonism and D₁R antagonism, kurarinone might be a potential compound that can alleviate clinical symptoms of Parkinson's disease and other NDDs.

Melatonin Analogues Potently Inhibit MAO-B and Protect PC12 Cells against Oxidative Stress

Monoamine oxidase B (MAO-B) metabolizes dopamine and plays an important role in oxidative stress by altering the redox state of neuronal and glial cells. MAO-B inhibitors are a promising therapeutical approach for Parkinson’s disease (PD). Herein, 24 melatonin analogues (3a–x) were synthesized as novel MAO-B inhibitors with the potential to counteract oxidative stress in neuronal PC12 cells. Structure elucidation, characterization, and purity of the synthesized compounds were performed using ¹H-NMR, ¹³C-NMR, HRMS, and HPLC. At 10 µM, 12 compounds showed >50% MAO-B inhibition. Among them, compounds 3n, 3r, and 3u–w showed >70% inhibition of MAO-B and IC₅₀ values of 1.41, 0.91, 1.20, 0.66, and 2.41 µM, respectively. When compared with the modest selectivity index of rasagiline (II, a well-known MAO-B inhibitor, SI > 50), compounds 3n, 3r, 3u, and 3v demonstrated better selectivity indices (SI > 71, 109, 83, and 151, respectively). Furthermore, compounds 3n and 3r exhibited safe neurotoxicity profiles in PC12 cells and reversed 6-OHDA- and rotenone-induced neuronal oxidative stress. Both compounds significantly up-regulated the expression of the anti-oxidant enzyme, heme oxygenase (HO)-1. Treatment with Zn(II)-protoporphyrin IX (ZnPP), a selective HO-1 inhibitor, abolished the neuroprotective effects of the tested compounds, suggesting a critical role of HO-1 up-regulation. Both compounds increased the nuclear translocation of Nrf2, which is a key regulator of the antioxidative response. Taken together, these data show that compounds 3n and 3r could be further exploited for their multi-targeted role in oxidative stress-related PD therapy.

Discovery of 3,4-dichloro-N-(1H-indol-5-yl)benzamide: A highly potent, selective, and competitive hMAO-B inhibitor with high BBB permeability profile and neuroprotective action

Since there is no disease-modifying treatment discovered yet for Parkinson's disease (PD), there is still a vital need to develop novel selective monoamine oxidase B (MAO-B) inhibitors as promising therapeutically active candidates for PD patients. Herein, we report the design, synthesis, and full characterization of new twenty-six indole derivatives as potential human MAO-B (hMAO-B) selective inhibitors. Six compounds (2i, 3b-e, and 5) exhibited low micromolar to nanomolar inhibitory activities over hMAO-B; compared to our recently reported N-substituted indole-based lead compound VIII (hMAO-B IC₅₀ = 777 nM), compound 5 (3,4-dichloro-N-(1H-indol-5-yl)benzamide) exhibited 18-fold increase in potency (IC₅₀ = 42 nM). A selectivity study over hMAO-A revealed an excellent selectivity index of compound 5 (SI > 2375) with a 47-fold increase compared to rasagiline (II, a well-known MAO-B inhibitor, SI > 50). A further kinetic evaluation of compound 5 over hMAO-B showed a reversible and competitive mode of inhibition with K_i value of 7 nM. Highly effective permeability and high CNS bioavailability of compound 5 with P_e = 54.49 × 10^-6 cm/s were demonstrated. Compound 5 also exhibited a low cytotoxicity profile and a promising neuroprotective effect against the 6-hydroxydopamine-induced neuronal cell damage in PC12 cells, which was more effective than that of rasagiline. Docking simulations on both hMAO-B and hMAO-A supported the in vitro data and served as further molecular evidence. Accordingly, we report the discovery of compound 5 as one of the most potent indole-based MAO-B inhibitors to date which is noteworthy to be further evaluated as a promising agent for PD treatment.

The Emerging Role of Circular RNAs in Alzheimer's Disease and Parkinson's Disease

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are two neurodegenerative diseases (NDDs) commonly found in elderly patients that are difficult to diagnose and lack effective treatment. Currently, the available diagnostic methods for these two NDDs do not meet clinical diagnostic expectations. Circular RNAs (circRNAs) are a diverse group of endogenous non-coding RNAs (ncRNAs) found in eukaryotic cells. Emerging studies suggest that altered expression of circRNAs is involved in the pathological processes of NDDs. CircRNAs could also prove to be promising biomarkers for the early diagnosis of NDDs such as AD and PD. Growing evidence has improved our knowledge of the roles of circRNAs in NDDs, which may lead to new therapeutic approaches that target transcription for preventing neurodegeneration. In this review, we describe the formation mechanisms and functions of circRNAs as well as methods of validation. We also discuss the emerging role of circRNAs in the pathophysiology of AD and PD and their potential value as biomarkers and therapeutic targets for AD and PD in the future.

Both metal-chelating and free radical-scavenging synthetic pentapeptides as efficient inhibitors of reactive oxygen species generation

The very first Fe(iii)-peptide chelators exhibiting antioxidant properties thanks to an unprecedented dual direct/indirect mode of action.

The current status of pharmacotherapy for the treatment of Parkinson's disease: transition from single-target to multitarget therapy

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons. Motor features such as tremor, rigidity, bradykinesia and postural instability are common traits of PD. Current treatment options provide symptomatic relief to the condition but are unable to reverse disease progression. The conventional single-target therapeutic approach might not always induce the desired effect owing to the multifactorial nature of PD. Hence, multitarget strategies have been proposed to simultaneously target multiple proteins involved in the development of PD. Herein, we provide an overview of the pathogenesis of PD and the current pharmacotherapies. Furthermore, rationales and examples of multitarget approaches that have been tested in preclinical trials for the treatment of PD are also discussed.

Design, synthesis and pharmacological evaluation of N-benzyl-piperidinyl-aryl-acylhydrazone derivatives as donepezil hybrids: Discovery of novel multi-target anti-alzheimer prototype drug candidates

A new series of sixteen multifunctional N-benzyl-piperidine-aryl-acylhydrazones hybrid derivatives was synthesized and evaluated for multi-target activities related to Alzheimer's disease (AD). The molecular hybridization approach was based on the combination, in a single molecule, of the pharmacophoric N-benzyl-piperidine subunit of donepezil, the substituted hydroxy-piperidine fragment of the AChE inhibitor LASSBio-767, and an acylhydrazone linker, a privileged structure present in a number of synthetic aryl- and aryl-acylhydrazone derivatives with significant AChE and anti-inflammatory activities. Among them, compounds 4c, 4d, 4g and 4j presented the best AChE inhibitory activities, but only compounds 4c and 4g exhibited concurrent anti-inflammatory activity in vitro and in vivo, against amyloid beta oligomer (AβO) induced neuroinflammation. Compound 4c also showed the best in vitro and in vivo neuroprotective effects against AβO-induced neurodegeneration. In addition, compound 4c showed a similar binding mode to donepezil in both acetylated and free forms of AChE enzyme in molecular docking studies and did not show relevant toxic effects on in vitro and in vivo assays, with good predicted ADME parameters in silico. Overall, all these results highlighted compound 4c as a promising and innovative multi-target drug prototype candidate for AD treatment.

Design, synthesis and evaluation of novel dual monoamine-cholinesterase inhibitors as potential treatment for Alzheimer's disease

Current novel therapeutic approach suggests that multifunctional compounds with diverse biological properties and a single bioavailability and pharmacokinetic metabolism, will produce higher significant advantages in treatment of neurodegenerative diseases, such as Alzheimer's disease (AD). Based on this rational, a new class of cholinesterase (ChE)-monoamine oxidase (MAO) inhibitors were designed and synthesized by amalgamating the propargyl moiety of the irreversible selective MAO-B inhibitor, neuroprotective/neurorestorative anti-Parkinsonian drug, rasagiline, into the "N-methyl" position of the ChE inhibitor, anti-AD drug rivastigmine. Initially, we examined the MAO and ChE inhibitory effect of these novel compounds, MT series in vitro and in vivo. Among MT series, MT-031 exhibited higher potency as a dual MAO-A and ChE inhibitor compared to other compounds in acute-treated mice. Additionally, MT-031 was found to increase the striatal levels of dopamine (DA), serotonin (5-HT) and norepinephrine (NE), and prevent the metabolism of DA and 5-HT. Finally, we have demonstrated that MT-031 exerted neuroprotective effect against H2O2-induced neurotoxicity and reactive oxygen species generation in human neuroblastoma SH-SY5Y cells. These findings provide evidence that MT-031 is a potent brain permeable novel multifunctional, neuroprotective and MAO-A/ChE inhibitor, preserves in one molecule entity some of the beneficial properties of its parent drugs, rasagiline and rivastigmine, and thus may be indicated as novel therapeutic approach for AD.

Discovery of New Chemical Entities for Old Targets: Insights on the Lead Optimization of Chromone-Based Monoamine Oxidase B (MAO-B) Inhibitors

The discovery of new chemical entities endowed with potent, selective, and reversible monoamine oxidase B inhibitory activity is a clinically relevant subject. Therefore, a small library of chromone derivatives was synthesized and screened toward human monoamine oxidase isoforms (hMAO-A and hMAO-B). The structure-activity relationships studies strengthen the importance of the amide spacer and the direct linkage of carbonyl group to the γ-pyrone ring, along with the presence of meta and para substituents in the exocyclic ring. The most potent MAO-B inhibitors were N-(3'-chlorophenyl)-4-oxo-4H-chromene-3-carboxamide (20) (IC50 = 403 pM) and N-(3',4'-dimethylphenyl)-4-oxo-4H-chromene-3-carboxamide (27) (IC50 = 669 pM), acting as competitive and noncompetitive reversible inhibitors, respectively. Computational docking studies provided insights into enzyme-inhibitor interactions and a rationale for the observed selectivity and potency. Compound 27 stands out due to its favorable toxicological profile and physicochemical properties, which pointed toward blood-brain barrier permeability, thus being a valid candidate for subsequent animal studies.

Potential neuroprotective properties of epigallocatechin-3-gallate (EGCG)

Neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) enforce an overwhelming social and economic burden on society. They are primarily characterized through the accumulation of modified proteins, which further trigger biological responses such as inflammation, oxidative stress, excitotoxicity and modulation of signalling pathways. In a hope for cure, these diseases have been studied extensively over the last decade to successfully develop symptom-oriented therapies. However, so far no definite cure has been found. Therefore, there is a need to identify a class of drug capable of reversing neural damage and preventing further neural death. This review therefore assesses the reliability of the neuroprotective benefits of epigallocatechin-gallate (EGCG) by shedding light on their biological, pharmacological, antioxidant and metal chelation properties, with emphasis on their ability to invoke a range of cellular mechanisms in the brain. It also discusses the possible use of nanotechnology to enhance the neuroprotective benefits of EGCG.

Conjugates of γ-Carbolines and Phenothiazine as new selective inhibitors of butyrylcholinesterase and blockers of NMDA receptors for Alzheimer Disease

Alzheimer disease is a multifactorial pathology and the development of new multitarget neuroprotective drugs is promising and attractive. We synthesized a group of original compounds, which combine in one molecule γ-carboline fragment of dimebon and phenothiazine core of methylene blue (MB) linked by 1-oxo- and 2-hydroxypropylene spacers. Inhibitory activity of the conjugates toward acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and structurally close to them carboxylesterase (CaE), as well their binding to NMDA-receptors were evaluated in vitro and in silico. These newly synthesized compounds showed significantly higher inhibitory activity toward BChE with IC50 values in submicromolar and micromolar range and exhibited selective inhibitory action against BChE over AChE and CaE. Kinetic studies for the 9 most active compounds indicated that majority of them were mixed-type BChE inhibitors. The main specific protein-ligand interaction is π-π stacking of phenothiazine ring with indole group of Trp82. These compounds emerge as promising safe multitarget ligands for the further development of a therapeutic approach against aging-related neurodegenerative disorders such as Alzheimer and/or other pathological conditions.

Prevention of the degeneration of human dopaminergic neurons in an astrocyte co-culture system allowing endogenous drug metabolism

BACKGROUND AND PURPOSE

Few neuropharmacological model systems use human neurons. Moreover, available test systems rarely reflect functional roles of co-cultured glial cells. There is no human in vitro counterpart of the widely used 1-methyl-4-phenyl-tetrahydropyridine (MPTP) mouse model of Parkinson's disease

EXPERIMENTAL APPROACH

We generated such a model by growing an intricate network of human dopaminergic neurons on a dense layer of astrocytes. In these co-cultures, MPTP was metabolized to 1-methyl-4-phenyl-pyridinium (MPP(+) ) by the glial cells, and the toxic metabolite was taken up through the dopamine transporter into neurons. Cell viability was measured biochemically and by quantitative neurite imaging, siRNA techniques were also used.

KEY RESULTS

We initially characterized the activation of PARP. As in mouse models, MPTP exposure induced (poly-ADP-ribose) synthesis and neurodegeneration was blocked by PARP inhibitors. Several different putative neuroprotectants were then compared in mono-cultures and co-cultures. Rho kinase inhibitors worked in both models; CEP1347, ascorbic acid or a caspase inhibitor protected mono-cultures from MPP(+) toxicity, but did not protect co-cultures, when used alone or in combination. Application of GSSG prevented degeneration in co-cultures, but not in mono-cultures. The surprisingly different pharmacological profiles of the models suggest that the presence of glial cells, and the in situ generation of the toxic metabolite MPP(+) within the layered cultures played an important role in neuroprotection.

CONCLUSIONS AND IMPLICATIONS

Our new model system is a closer model of human brain tissue than conventional cultures. Its use for screening of candidate neuroprotectants may increase the predictiveness of a test battery.

Effect of the semen extract of Cuscuta chinensis on inflammatory responses in LPS-stimulated BV-2 microglia

AIM

To investigate the anti-inflammatory activities of the semen extract of Cuscuta chinensis Lam. (Cuscutae Semen; CS) on the production of inflammatory mediators, nitric oxide (NO), prostaglandin 2 (PGE2), and proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated BV-2 microglia.

METHOD

BV-2 cells were treated with CS extract for 30 min, and then stimulated with LPS or without for 24 h. The levels of NO, PGE2 and proinflammatory cytokines were measured by Griess assay and ELISA. The expression of inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 mRNA and protein was determined by RT-PCR and Western blot, respectively. The phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK), and the nuclear expression of nuclear factor (NF)-κB p65 were investigated by Western blot analysis.

RESULTS

CS extract significantly decreased the production of NO and PGE2 by suppressing the expression of iNOS and COX-2 in activated microglia. CS extract decreased the production of TNF-α, IL-1β, and IL-6 by down-regulating their transcription levels. In addition, CS extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of NF-κB p65 in activated microglia.

CONCLUSION

These results indicate that CS extract is capable of suppressing the inflammatory response by microglia activation, suggesting that CS extract has potential in the treatment of brain inflammation.

Protection from neurodegeneration in the 6-hydroxydopamine (6-OHDA) model of Parkinson's with novel 1-hydroxypyridin-2-one metal chelators

We report that novel 1-hydroxypyridin-2-ones show comparable neuroprotective results to deferiprone in a cell culture model of Parkinson's disease.

Transcription factors Foxa1 and Foxa2 are required for adult dopamine neurons maintenance

The proteins Foxa1 and Foxa2 belong to the forkhead family of transcription factors and are involved in the development of several tissues, including liver, pancreas, lung, prostate, and the neural system. Both Foxa1 and Foxa2 are also crucial for the specification and differentiation of dopamine (DA) neurons during embryonic development, while about 30% of mice with an embryonic deletion of a single allele of the Foxa2 gene exhibit an age-related asymmetric loss of DA neurons and develop locomotor symptoms resembling Parkinson's disease (PD). Notably, both Foxa1 and Foxa2 factors continue to be expressed in the adult dopamine system. To directly assess their functions selectively in adult DA neurons, we induced genetic deletions of Foxa1/2 transcription factors in mice using a tamoxifen inducible tissue-specific CreERT2 recombinase expressed under control of the dopamine transporter (DAT) promoter (DATCreERT2). The conditional DA neurons-specific ablation of both genes, but not of Foxa2 alone, in early adulthood, caused a decline of striatal dopamine and its metabolites, along with locomotor deficits. At early pre-symptomatic stages, we observed a decline in aldehyde dehydrogenase family 1, subfamily A1 (Aldh1a1) protein expression in DA neurons. Further analyses revealed a decline of aromatic amino acid decarboxylase (AADC) and a complete loss of DAT expression in these neurons. These molecular changes ultimately led to a reduction of DA neuron numbers in the substantia nigra pars compacta (SNpc) of aged cFoxa1/2^−/− mice, resembling the progressive course of PD in humans. Altogether, in this study, we address the molecular, cellular, and functional role of both Foxa1 and Foxa2 factors in the maintenance of the adult dopamine system which may help to find better approaches for PD treatment.

Canadian boreal pulp and paper feedstocks contain neuroactive substances that interact in vitro with GABA and dopaminergic systems in the brain

Pulp and paper wood feedstocks have been previously implicated as a source of chemicals with the ability to interact with or disrupt key neuroendocrine endpoints important in the control of reproduction. We tested nine Canadian conifers commonly used in pulp and paper production as well as 16 phytochemicals that have been observed in various pulp and paper mill effluent streams for their ability to interact in vitro with the enzymes monoamine oxidase (MAO), glutamic acid decarboxylase (GAD), and GABA-transaminase (GABA-T), and bind to the benzodiazepine-binding site of the GABA(A) receptor (GABA(A)-BZD). These neuroendocrine endpoints are also important targets for treatment of neurological disorders such as anxiety, epilepsy, or depression. MAO and GAD were inhibited by various conifer extracts of different polarities, including major feedstocks such as balsam fir, black spruce, and white spruce. MAO was selectively stimulated or inhibited by many of the tested phytochemicals, with inhibition observed by a group of phenylpropenes (e.g. isoeugenol and vanillin). Selective GAD inhibition was also observed, with all of the resin acids tested being inhibitory. GABA(A)-BZD ligand displacement was also observed. We compiled a table identifying which of these phytochemicals have been described in each of the species tested here. Given the diversity of conifer species and plant chemicals with these specific neuroactivities, it is reasonable to propose that MAO and GAD inhibition reported in effluents is phytochemical in origin. We propose disruption of these neuroendocrine endpoints as a possible mechanism of reproductive inhibition, and also identify an avenue for potential research and sourcing of conifer-derived neuroactive natural products.

Novel (coumarin-3-yl)carbamates as selective MAO-B inhibitors: synthesis, in vitro and in vivo assays, theoretical evaluation of ADME properties and docking study

A series of (coumarin-3-yl)carbamates was synthesized and evaluated in vitro as monoamine oxidase (MAO-A and MAO-B) inhibitors. Most of the new compounds selectively inhibited MAO-B isoenzyme with IC50 values in the micro or nanoMolar ranges. Since these compounds must achieve the brain cells, theoretical evaluation of ADME properties were also carried out. Compound 8 (benzyl(coumarin-3-yl)carbamate), which presented the most interesting in vitro MAO-B inhibitory profile (IC50 against MAO-B = 45 nM), was subjected to further studies. This in vitro MAO-B inhibitory activity is comparable with that of the selegiline, the reference compound (IC50 against MAO-B = 20 nM). Taking into account the in vitro results of compound 8, in vivo assays and docking calculations were also carried out for this derivative.