Patient-derived three-dimensional cortical neurospheres to model Parkinson's disease.

There are currently no preventive or disease-modifying therapies for Parkinson's Disease (PD). Failures in clinical trials necessitate a re-evaluation of existing pre-clinical models in order to adopt systems that better recapitulate underlying disease mechanisms and better predict clinical outcomes. In recent years, models utilizing patient-derived induced pluripotent stem cells (iPSC) have emerged as attractive models to recapitulate disease-relevant neuropathology in vitro without exogenous overexpression of disease-related pathologic proteins.

A Brain-Penetrant Stearoyl-CoA Desaturase Inhibitor Reverses α-Synuclein Toxicity.

Increasing evidence has shown that Parkinson's disease (PD) impairs midbrain dopaminergic, cortical and other neuronal subtypes in large part due to the build-up of lipid- and vesicle-rich α-synuclein (αSyn) cytotoxic inclusions. We previously identified stearoyl-CoA desaturase (SCD) as a potential therapeutic target for synucleinopathies. A brain-penetrant SCD inhibitor, YTX-7739, was developed and has entered Phase 1 clinical trials.

Non-clinical Pharmacology of YTX-7739: a Clinical Stage Stearoyl-CoA Desaturase Inhibitor Being Developed for Parkinson's Disease.

Stearoyl-CoA desaturase (SCD) is a potential therapeutic target for Parkinson's and related neurodegenerative diseases. SCD inhibition ameliorates neuronal toxicity caused by aberrant α-synuclein, a lipid-binding protein implicated in Parkinson's disease. Its inhibition depletes monounsaturated fatty acids, which may modulate α-synuclein conformations and membrane interactions.

Different Fumaric Acid Esters Elicit Distinct Pharmacologic Responses.

Objective: To test the hypothesis that dimethyl fumarate (DMF, Tecfidera) elicits different biological changes from DMF combined with monoethyl fumarate (MEF) (Fumaderm, a psoriasis therapy), we investigated DMF and MEF in rodents and cynomolgus monkeys. Possible translatability of findings was explored with lymphocyte counts from a retrospective cohort of patients with MS.

Methods: In rodents, we evaluated pharmacokinetic and pharmacodynamic effects induced by DMF and MEF monotherapies or in combination (DMF/MEF).

Inhibiting Stearoyl-CoA Desaturase Ameliorates α-Synuclein Cytotoxicity.

The lack of disease-modifying treatments for neurodegenerative disease stems in part from our rudimentary understanding of disease mechanisms and the paucity of targets for therapeutic intervention. Here we used an integrated discovery paradigm to identify a new therapeutic target for diseases caused by α-synuclein (α-syn), a small lipid-binding protein that misfolds and aggregates in Parkinson's disease and other disorders. Using unbiased phenotypic screening, we identified a series of compounds that were cytoprotective against α-syn-mediated toxicity by inhibiting the highly conserved enzyme stearoyl-CoA desaturase (SCD).

Potent PDZ-Domain PICK1 Inhibitors that Modulate Amyloid Beta-Mediated Synaptic Dysfunction.

Protein interacting with C kinase (PICK1) is a scaffolding protein that is present in dendritic spines and interacts with a wide array of proteins through its PDZ domain. The best understood function of PICK1 is regulation of trafficking of AMPA receptors at neuronal synapses via its specific interaction with the AMPA GluA2 subunit. Disrupting the PICK1-GluA2 interaction has been shown to alter synaptic plasticity, a molecular mechanism of learning and memory.

Therapeutic strategies for targeting neurodegenerative protein misfolding disorders.

Neurodegenerative diseases can arise from a multitude of different pathological drivers, however protein misfolding appears to be a common molecular feature central to several disorders. Protein folding, and attainment of correct secondary and tertiary structure, is essential for proper protein function. Protein misfolding gives rise to structural perturbations that can result in loss of protein function or a gain of toxic function, such as through aggregation, either of which can initiate and propagate biological responses that are deleterious to cells.

Discovery of a highly selective chemical inhibitor of matrix metalloproteinase-9 (MMP-9) that allosterically inhibits zymogen activation.

Aberrant activation of matrix metalloproteinases (MMPs) is a common feature of pathological cascades observed in diverse disorders, such as cancer, fibrosis, immune dysregulation, and neurodegenerative diseases. MMP-9, in particular, is highly dynamically regulated in several pathological processes. Development of MMP inhibitors has therefore been an attractive strategy for therapeutic intervention.

Addendum: The antibody aducanumab reduces Aβ plaques in Alzheimer's disease.

This corrects the article DOI: 10.1038/nature21361.

Dimethyl fumarate improves white matter function following severe hypoperfusion: Involvement of microglia/macrophages and inflammatory mediators.

The brain's white matter is highly vulnerable to reductions in cerebral blood flow via mechanisms that may involve elevated microgliosis and pro-inflammatory pathways. In the present study, the effects of severe cerebral hypoperfusion were investigated on white matter function and inflammation. Male C57Bl/6J mice underwent bilateral common carotid artery stenosis and white matter function was assessed at seven days with electrophysiology in response to evoked compound action potentials (CAPs) in the corpus callosum.

The NRF2 transcriptional target, OSGIN1, contributes to monomethyl fumarate-mediated cytoprotection in human astrocytes.

Dimethyl fumarate (DMF) is indicated for the treatment of relapsing multiple sclerosis and may exert therapeutic effects via activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway. Following oral DMF administration, central nervous system (CNS) tissue is predominantly exposed to monomethyl fumarate (MMF), the bioactive metabolite of DMF, which can stabilize NRF2 and induce antioxidant gene expression; however, the detailed NRF2-dependent mechanisms modulated by MMF that lead to cytoprotection are unknown. Our data identify a mechanism for MMF-mediated cytoprotection in human astrocytes that functions in an OSGIN1-dependent manner, specifically via upregulation of the OSGIN1-61 kDa isoform.

Dimethyl fumarate alters microglia phenotype and protects neurons against proinflammatory toxic microenvironments.

Delayed-release dimethyl fumarate (DMF) is an approved treatment for multiple sclerosis (MS). Microglia are considered central to MS pathophysiology, however the effects of DMF and the primary metabolite monomethyl fumarate (MMF) on microglia are not well characterized. We demonstrated that DMF and MMF altered transcriptional responses in primary microglia related to the nuclear factor (erythroid-derived 2)-like 2 pathway.

The antibody aducanumab reduces Aβ plaques in Alzheimer's disease.

Alzheimer's disease (AD) is characterized by deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain, accompanied by synaptic dysfunction and neurodegeneration. Antibody-based immunotherapy against Aβ to trigger its clearance or mitigate its neurotoxicity has so far been unsuccessful. Here we report the generation of aducanumab, a human monoclonal antibody that selectively targets aggregated Aβ.

Dimethyl fumarate treatment induces adaptive and innate immune modulation independent of Nrf2.

Dimethyl fumarate (DMF) (BG-12, Tecfidera) is a fumaric acid ester (FAE) that was advanced as a multiple sclerosis (MS) therapy largely for potential neuroprotection as it was recognized that FAEs are capable of activating the antioxidative transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, DMF treatment in randomized controlled MS trials was associated with marked reductions in relapse rate and development of active brain MRI lesions, measures considered to reflect CNS inflammation. Here, we investigated the antiinflammatory contribution of Nrf2 in DMF treatment of the MS model, experimental autoimmune encephalomyelitis (EAE).

Repurposing the NRF2 Activator Dimethyl Fumarate as Therapy Against Synucleinopathy in Parkinson's Disease.

Aims: This preclinical study was aimed at determining whether pharmacological targeting of transcription factor NRF2, a master controller of many homeostatic genes, might provide a disease-modifying therapy in the animal model of Parkinson's disease (PD) that best reproduces the main hallmark of this pathology, that is, α-synucleinopathy, and associated events, including nigral dopaminergic cell death, oxidative stress, and neuroinflammation.

Results: Pharmacological activation of NRF2 was achieved at the basal ganglia by repurposing dimethyl fumarate (DMF), a drug already in use for the treatment of multiple sclerosis. Daily oral gavage of DMF protected nigral dopaminergic neurons against α-SYN toxicity and decreased astrocytosis and microgliosis after 1, 3, and 8 weeks from stereotaxic delivery to the ventral midbrain of recombinant adeno-associated viral vector expressing human α-synuclein.

Pharmacodynamics of Dimethyl Fumarate Are Tissue Specific and Involve NRF2-Dependent and -Independent Mechanisms.

Aims: Gastro-resistant dimethyl fumarate (DMF) is an oral therapeutic indicated for the treatment of relapsing multiple sclerosis. Recent data suggest that a primary pharmacodynamic response to DMF treatment is activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway; however, the gene targets modulated downstream of NRF2 that contribute to DMF-dependent effects are poorly understood.

Results: Using wild-type and NRF2 knockout mice, we characterized DMF transcriptional responses throughout the brain and periphery to understand DMF effects in vivo and to explore the necessity of NRF2 in this process.

BIIB042, a novel γ-secretase modulator, reduces amyloidogenic Aβ isoforms in primates and rodents and plaque pathology in a mouse model of Alzheimer's disease.

Reducing the production of larger aggregation-prone amyloid β-peptides (Aβ) remains an untested therapeutic approach for reducing the appearance and growth of Aβ plaques in the brain, which are a hallmark pathological feature of Alzheimer's disease. γ-Secretase modulators (GSMs) are therapeutics that impact γ-secretase-dependent cleavage of amyloid precursor protein to promote the production of shorter Aβ peptides that are less prone to aggregation and plaque deposition. This is accomplished without inhibiting overall γ-secretase function and cleavage of other substrates, which is believed to be a source of deleterious side effects.

DMF, but not other fumarates, inhibits NF-κB activity in vitro in an Nrf2-independent manner.

Fumarate-containing pharmaceuticals are potent therapeutic agents that influence multiple cellular pathways. Despite proven clinical efficacy, there is a significant lack of data that directly defines the molecular mechanisms of action of related, yet distinct fumarate compounds. We systematically compared the impact of dimethyl fumarate (DMF), monomethyl fumarate (MMF) and a mixture of monoethyl fumarate salts (Ca(++), Mg(++), Zn(++); MEF) on defined cellular responses.

Neuronal development is promoted by weakened intrinsic antioxidant defences due to epigenetic repression of Nrf2.

Forebrain neurons have weak intrinsic antioxidant defences compared with astrocytes, but the molecular basis and purpose of this is poorly understood. We show that early in mouse cortical neuronal development in vitro and in vivo, expression of the master-regulator of antioxidant genes, transcription factor NF-E2-related-factor-2 (Nrf2), is repressed by epigenetic inactivation of its promoter. Consequently, in contrast to astrocytes or young neurons, maturing neurons possess negligible Nrf2-dependent antioxidant defences, and exhibit no transcriptional responses to Nrf2 activators, or to ablation of Nrf2's inhibitor Keap1.

Fumarates modulate microglia activation through a novel HCAR2 signaling pathway and rescue synaptic dysregulation in inflamed CNS.

Dimethyl fumarate (DMF), recently approved as an oral immunomodulatory treatment for relapsing-remitting multiple sclerosis (MS), metabolizes to monomethyl fumarate (MMF) which crosses the blood-brain barrier and has demonstrated neuroprotective effects in experimental studies. We postulated that MMF exerts neuroprotective effects through modulation of microglia activation, a critical component of the neuroinflammatory cascade that occurs in neurodegenerative diseases such as MS. To ascertain our hypothesis and define the mechanistic pathways involved in the modulating effect of fumarates, we used real-time PCR and biochemical assays to assess changes in the molecular and functional phenotype of microglia, quantitative Western blotting to monitor activation of postulated pathway components, and ex vivo whole-cell patch clamp recording of excitatory post-synaptic currents in corticostriatal slices from mice with experimental autoimmune encephalomyelitis (EAE), a model for MS, to study synaptic transmission.

Dimethyl fumarate and monoethyl fumarate exhibit differential effects on KEAP1, NRF2 activation, and glutathione depletion in vitro.

Delayed-release dimethyl fumarate (also known as gastro-resistant dimethyl fumarate), an oral therapeutic containing dimethyl fumarate (DMF) as the active ingredient, is currently approved for the treatment of relapsing multiple sclerosis. DMF is also a component in a distinct mixture product with 3 different salts of monoethyl fumarate (MEF), which is marketed for the treatment of psoriasis. Previous studies have provided insight into the pharmacologic properties of DMF, including modulation of kelch-like ECH-associated protein 1 (KEAP1), activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway, and glutathione (GSH) modulation; however, those of MEF remain largely unexplored.

Neuroprotective dimethyl fumarate synergizes with immunomodulatory interferon beta to provide enhanced axon protection in autoimmune neuroinflammation.

Introduction: Despite recent advances in development of treatments for multiple sclerosis, there is still an unmet need for more effective and also safe therapies. Based on the modes of action of interferon-beta (IFN-β) and dimethyl fumarate (DMF), we hypothesized that anti-inflammatory and neuroprotective effects may synergize in experimental autoimmune encephalomyelitis (EAE).

Methods: EAE was induced in C57BL/6 mice by immunization with MOG35-55-peptide.

Synapto-depressive effects of amyloid beta require PICK1.

Amyloid beta (Aβ), a key component in the pathophysiology of Alzheimer's disease, is thought to target excitatory synapses early in the disease. However, the mechanism by which Aβ weakens synapses is not well understood. Here we showed that the PDZ domain protein, protein interacting with C kinase 1 (PICK1), was required for Aβ to weaken synapses.

Tolerability and pharmacokinetics of delayed-release dimethyl fumarate administered with and without aspirin in healthy volunteers.

Background: Delayed-release dimethyl fumarate (DR-DMF) has cytoprotective and antiinflammatory properties and has recently been approved in the United States as an oral treatment for relapsing forms of multiple sclerosis. The most common adverse events associated with DR-DMF are flushing and gastrointestinal (GI) events, the incidences of which diminish over time.

Objective: The purpose of this study was to evaluate the tolerability and pharmacokinetic (PK) profile of DR-DMF with or without concomitant acetylsalicylic acid (aspirin), a cyclooxygenase inhibitor.