Target occupancy study and whole-body dosimetry with a MAGL PET ligand [C]PF-06809247 in non-human primates.

Background: Monoacylglycerol lipase (MAGL) is a key serine hydrolase which terminates endocannabinoid signaling and regulates arachidonic acid driven inflammatory responses within the central nervous system. To develop [C]PF-06809247 into a clinically usable MAGL positron emission tomography (PET) radioligand, we assessed the occupancy of MAGL by an inhibitor in the non-human primate (NHP) brain. Additionally, we measured the whole-body distribution of [C]PF-06809247 in NHP and estimated human effective radiation doses.

Sustained reduction of serum neurofilament light chain over 7 years by alemtuzumab in early relapsing-remitting MS.

Background: Alemtuzumab efficacy and safety was demonstrated in CARE-MS I and extension studies (CAMMS03409; TOPAZ).

Objective: Evaluate serum neurofilament light chain (sNfL) in CARE-MS I patients and highly active disease (HAD) subgroup, over 7 and 2 years for alemtuzumab and subcutaneous interferon beta-1a (SC IFNB-1a), respectively.

Methods: Patients received SC IFNB-1a 44 µg 3×/week or alemtuzumab 12 mg/day at baseline and month 12, with further as-needed 3-day courses.

Multiplex proteomics identifies novel CSF and plasma biomarkers of early Alzheimer's disease.

To date, the development of disease-modifying therapies for Alzheimer's disease (AD) has largely focused on the removal of amyloid beta Aβ fragments from the CNS. Proteomic profiling of patient fluids may help identify novel therapeutic targets and biomarkers associated with AD pathology. Here, we applied the Olink™ ProSeek immunoassay to measure 270 CSF and plasma proteins across 415 Aβ- negative cognitively normal individuals (Aβ- CN), 142 Aβ-positive CN (Aβ+ CN), 50 Aβ- mild cognitive impairment (MCI) patients, 75 Aβ+ MCI patients, and 161 Aβ+ AD patients from the Swedish BioFINDER study.

Free Water in White Matter Differentiates MCI and AD From Control Subjects.

Recent evidence shows that neuroinflammation plays a role in many neurological diseases including mild cognitive impairment (MCI) and Alzheimer's disease (AD), and that free water (FW) modeling from clinically acquired diffusion MRI (DTI-like acquisitions) can be sensitive to this phenomenon. This FW index measures the fraction of the diffusion signal explained by isotropically unconstrained water, as estimated from a bi-tensor model. In this study, we developed a simple but powerful whole-brain FW measure designed for easy translation to clinical settings and potential use as a priori outcome measure in clinical trials.

Identification and Development of an Irreversible Monoacylglycerol Lipase (MAGL) Positron Emission Tomography (PET) Radioligand with High Specificity.

Monoacylglycerol lipase (MAGL), a serine hydrolase extensively expressed throughout the brain, serves as a key gatekeeper regulating the tone of endocannabinoid signaling. Preclinically, inhibition of MAGL is known to provide therapeutic benefits for a number of neurological disorders. The availability of a MAGL-specific positron emission tomography (PET) ligand would considerably facilitate the development and clinical characterization of MAGL inhibitors via noninvasive and quantitative PET imaging.

Inhibition of 2-AG hydrolysis differentially regulates blood brain barrier permeability after injury.

Background: Acute neurological insults caused by infection, systemic inflammation, ischemia, or traumatic injury are often associated with breakdown of the blood-brain barrier (BBB) followed by infiltration of peripheral immune cells, cytotoxic proteins, and water. BBB breakdown and extravasation of these peripheral components into the brain parenchyma result in inflammation, oxidative stress, edema, excitotoxicity, and neurodegeneration. These downstream consequences of BBB dysfunction can drive pathophysiological processes and play a substantial role in the morbidity and mortality of acute and chronic neurological insults, and contribute to long-term sequelae.

Discovery of Trifluoromethyl Glycol Carbamates as Potent and Selective Covalent Monoacylglycerol Lipase (MAGL) Inhibitors for Treatment of Neuroinflammation.

Monoacylglycerol lipase (MAGL) inhibition provides a potential treatment approach to neuroinflammation through modulation of both the endocannabinoid pathway and arachidonoyl signaling in the central nervous system (CNS). Herein we report the discovery of compound 15 (PF-06795071), a potent and selective covalent MAGL inhibitor, featuring a novel trifluoromethyl glycol leaving group that confers significant physicochemical property improvements as compared with earlier inhibitor series with more lipophilic leaving groups. The design strategy focused on identifying an optimized leaving group that delivers MAGL potency, serine hydrolase selectivity, and CNS exposure while simultaneously reducing log  D, improving solubility, and minimizing chemical lability.

Inhibition of monoacylglycerol lipase terminates diazepam-resistant status epilepticus in mice and its effects are potentiated by a ketogenic diet.

Objective: Status epilepticus (SE) is a life-threatening and commonly drug-refractory condition. Novel therapies are needed to rapidly terminate seizures to prevent mortality and morbidity. Monoacylglycerol lipase (MAGL) is the key enzyme responsible for the hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-AG) and a major contributor to the brain pool of arachidonic acid (AA).

Azetidine and Piperidine Carbamates as Efficient, Covalent Inhibitors of Monoacylglycerol Lipase.

Monoacylglycerol lipase (MAGL) is the main enzyme responsible for degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the CNS. MAGL catalyzes the conversion of 2-AG to arachidonic acid (AA), a precursor to the proinflammatory eicosannoids such as prostaglandins. Herein we describe highly efficient MAGL inhibitors, identified through a parallel medicinal chemistry approach that highlighted the improved efficiency of azetidine and piperidine-derived carbamates.

Passive immunotherapy targeting amyloid-β reduces cerebral amyloid angiopathy and improves vascular reactivity.

Prominent cerebral amyloid angiopathy is often observed in the brains of elderly individuals and is almost universally found in patients with Alzheimer's disease. Cerebral amyloid angiopathy is characterized by accumulation of the shorter amyloid-β isoform(s) (predominantly amyloid-β40) in the walls of leptomeningeal and cortical arterioles and is likely a contributory factor to vascular dysfunction leading to stroke and dementia in the elderly. We used transgenic mice with prominent cerebral amyloid angiopathy to investigate the ability of ponezumab, an anti-amyloid-β40 selective antibody, to attenuate amyloid-β accrual in cerebral vessels and to acutely restore vascular reactivity.

A dysregulated endocannabinoid-eicosanoid network supports pathogenesis in a mouse model of Alzheimer's disease.

Although inflammation in the brain is meant as a defense mechanism against neurotoxic stimuli, increasing evidence suggests that uncontrolled, chronic, and persistent inflammation contributes to neurodegeneration. Most neurodegenerative diseases have now been associated with chronic inflammation, including Alzheimer's disease (AD). Whether anti-inflammatory approaches can be used to treat AD, however, is a major unanswered question.

The BMP coreceptor RGMb promotes while the endogenous BMP antagonist noggin reduces neurite outgrowth and peripheral nerve regeneration by modulating BMP signaling.

Repulsive guidance molecule b (RGMb) is a bone morphogenetic protein (BMP) coreceptor and sensitizer of BMP signaling, highly expressed in adult dorsal root ganglion (DRG) sensory neurons. We used a murine RGMb knock-out to gain insight into the physiological role of RGMb in the DRG, and address whether RGMb-mediated modulation of BMP signaling influences sensory axon regeneration. No evidence for altered development of the PNS and CNS was detected in RGMb(-/-) mice.

TRPV1 signaling: mechanistic understanding and therapeutic potential.

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel gated by noxious heat, vanilloids and extracellular protons. TRPV1 is acting as an important signal integrator in sensory nociceptors under physiological and pathological conditions including inflammation and neuropathy. Because of its integrative signaling properties in response to inflammatory stimuli, TRPV1 agonists and antagonists are predicted to inhibit the sensation of ongoing or burning pain that is reported by patients suffering from chronic pain, therefore offering an unprecedented advantage in selectively inhibiting painful signaling from where it is initiated.

Dynamic changes in the microRNA expression profile reveal multiple regulatory mechanisms in the spinal nerve ligation model of neuropathic pain.

Neuropathic pain resulting from nerve lesions or dysfunction represents one of the most challenging neurological diseases to treat. A better understanding of the molecular mechanisms responsible for causing these maladaptive responses can help develop novel therapeutic strategies and biomarkers for neuropathic pain. We performed a miRNA expression profiling study of dorsal root ganglion (DRG) tissue from rats four weeks post spinal nerve ligation (SNL), a model of neuropathic pain.

Dragon (repulsive guidance molecule b) inhibits IL-6 expression in macrophages.

Repulsive guidance molecule (RGM) family members RGMa, RGMb/Dragon, and RGMc/hemojuvelin were found recently to act as bone morphogenetic protein (BMP) coreceptors that enhance BMP signaling activity. Although our previous studies have shown that hemojuvelin regulates hepcidin expression and iron metabolism through the BMP pathway, the role of the BMP signaling mediated by Dragon remains largely unknown. We have shown previously that Dragon is expressed in neural cells, germ cells, and renal epithelial cells.

Monoacylglycerol lipase activity is a critical modulator of the tone and integrity of the endocannabinoid system.

Endocannabinoids are lipid molecules that serve as natural ligands for the cannabinoid receptors CB1 and CB2. They modulate a diverse set of physiological processes such as pain, cognition, appetite, and emotional states, and their levels and functions are tightly regulated by enzymatic biosynthesis and degradation. 2-Arachidonoylglycerol (2-AG) is the most abundant endocannabinoid in the brain and is believed to be hydrolyzed primarily by the serine hydrolase monoacylglycerol lipase (MAGL).

Depression-like phenotype following chronic CB1 receptor antagonism.

Rimonabant was the first clinically marketed cannabinoid (CB)(1) receptor antagonist developed to treat obesity. Unfortunately, CB(1) receptor antagonism produced adverse psychiatric events in patients. To determine whether this occurs pre-clinically, we investigated the effects of rimonabant in rodent models of mood disorders.

Genetic and functional analysis of human P2X5 reveals a distinct pattern of exon 10 polymorphism with predominant expression of the nonfunctional receptor isoform.

P2X5 is a member of the P2X family of ATP-gated nonselective cation channels, which exist as trimeric assemblies. P2X5 is believed to trimerize with another member of this family, P2X1. We investigated the single-nucleotide polymorphism (SNP) at the 3' splice site of exon 10 of the human P2X5 gene.

Dragon enhances BMP signaling and increases transepithelial resistance in kidney epithelial cells.

The neuronal adhesion protein Dragon acts as a bone morphogenetic protein (BMP) coreceptor that enhances BMP signaling. Given the importance of BMP signaling in nephrogenesis and its putative role in the response to injury in the adult kidney, we studied the localization and function of Dragon in the kidney. We observed that Dragon localized predominantly to the apical surfaces of tubular epithelial cells in the thick ascending limbs, distal convoluted tubules, and collecting ducts of mice.

Loss of retrograde endocannabinoid signaling and reduced adult neurogenesis in diacylglycerol lipase knock-out mice.

Endocannabinoids (eCBs) function as retrograde signaling molecules at synapses throughout the brain, regulate axonal growth and guidance during development, and drive adult neurogenesis. There remains a lack of genetic evidence as to the identity of the enzyme(s) responsible for the synthesis of eCBs in the brain. Diacylglycerol lipase-alpha (DAGLalpha) and -beta (DAGLbeta) synthesize 2-arachidonoyl-glycerol (2-AG), the most abundant eCB in the brain.

Simultaneous determination of 2-arachidonoylglycerol, 1-arachidonoylglycerol and arachidonic acid in mouse brain tissue using liquid chromatography/tandem mass spectrometry.

Endocannabinoids (ECs), such as anandamide (AEA) and 2-arachidonoylglycerol (2-AG), modulate a number of physiological processes, including pain, appetite and emotional state. Levels of ECs are tightly controlled by enzymatic biosynthesis and degradation in vivo. However, there is limited knowledge about the enzymes that terminate signaling of the major brain EC, 2-AG.

Voltage-gated sodium channels in pain states: role in pathophysiology and targets for treatment.

Pain is a major unmet medical need which has been causally linked to changes in sodium channel expression, modulation, or mutations that alter channel gating properties or current density in nociceptor neurons. Voltage-gated sodium channels activate (open) then rapidly inactivate in response to a depolarization of the plasma membrane of excitable cells allowing the transient flow of sodium ions thus generating an inward current which underlies the generation and conduction of action potentials (AP) in these cells. Activation and inactivation, as well as other gating properties, of sodium channel isoforms have different kinetics and voltage-dependent properties, so that the ensemble of channels that are present determine the electrogenic properties of specific neurons.

Periganglionic inflammation elicits a distally radiating pain hypersensitivity by promoting COX-2 induction in the dorsal root ganglion.

We have developed a model in which inflammation contiguous to and within a dorsal root ganglion (DRG) was generated by local application of complete Freund's adjuvant (CFA) to the L4 lumbar spinal nerve as it exits from the intervertebral foramen. The periganglionic inflammation (PGI) elicited a marked reduction in withdrawal threshold to mechanical stimuli and an increase in heat pain sensitivity in the ipsilateral hindpaw in the absence of any hindpaw inflammation. The pain sensitivity appeared within hours and lasted for a week.

COX2 in CNS neural cells mediates mechanical inflammatory pain hypersensitivity in mice.

A cardinal feature of peripheral inflammation is pain. The most common way of managing inflammatory pain is to use nonsteroidal antiinflammatory agents (NSAIDs) that reduce prostanoid production, for example, selective inhibitors of COX2. Prostaglandins produced after induction of COX2 in immune cells in inflamed tissue contribute both to the inflammation itself and to pain hypersensitivity, acting on peripheral terminals of nociceptors.