Dose-dependent inhibition of GCPII to prevent and treat cognitive impairment in the EAE model of multiple sclerosis

Hollinger, Kristen R.; Alt, Jesse; Riehm, Alison; Slusher, Barbara S.; Kaplin, Adam I.

doi:10.1016/j.brainres.2016.01.035

Cited by 21 publications

(21 citation statements)

References 30 publications

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“…On days 0 and 2, mice received an intraperitoneal injection of 250 ng pertussis toxin (List Biological Laboratories). EAE disease scores were blindly assigned as previously described 26 based on the following scale with 0.5 increments for intermediate scores: 0 = normal, 1 = limp tail, 2 = wobbly gait, 3 = dragging hind flank, 4 = hind limb paralysis, and 5 = quadriplegia. Experiments were conducted in duplicate.…”

Section: Methodsmentioning

confidence: 99%

Glutamine antagonism attenuates physical and cognitive deficits in a model of MS

Hollinger

Smith

Kirby

et al. 2019

Neurol Neuroimmunol Neuroinflamm

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ObjectiveTo measure the impact of JHU-083, a novel prodrug of the glutamine antagonist 6-diazo-5-oxo-l-norleucine, on immune cell proliferation and activation, along with physical and cognitive impairments associated with the experimental autoimmune encephalomyelitis (EAE) mouse model of MS.MethodsSplenic-derived T cells and bone marrow–derived dendritic cells (DCs) were cultured, activated, and treated daily with vehicle or JHU-083. Proliferation and activation were measured via flow cytometry and IncuCyte live cell analysis. C57BL/6 mice were immunized for EAE. Vehicle or JHU-083 was administered orally every other day either from the time of immunization in the prevention paradigm or from the time of disease onset in the treatment paradigm. Disease scores and body weight were monitored. In the treatment paradigm, cognition was evaluated using the Barnes maze test.ResultsJHU-083 selectively inhibits T-cell proliferation and decreases T-cell activation, with no effect on DCs. In vivo, orally administered JHU-083 significantly decreases EAE severity in both prevention and treatment paradigms and reverses EAE-induced cognitive impairment.ConclusionsJHU-083, a well-tolerated, brain penetrable glutamine antagonist, is a promising novel treatment for both the physical and cognitive deficits of MS.

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Section: Methodsmentioning

confidence: 99%

Glutamine antagonism attenuates physical and cognitive deficits in a model of MS

Hollinger

Smith

Kirby

et al. 2019

Neurol Neuroimmunol Neuroinflamm

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“…On days 0 and 2, mice received an intraperitoneal injection of 250 ng pertussis toxin (List Biological Laboratories). EAE disease scores were assigned by an observer blinded to the treatment as previously described [9] based on the following scale with 0.5 increments for intermediate scores: 0=normal, 1=limp tail, 2=wobbly gait, 3=dragging hind flank, 4=hind limb paralysis, 5=quadriplegia. Experiments were conducted in duplicate.…”

Section: Eae Immunizations and Scoringmentioning

confidence: 99%

“…To determine the effects of GCPII inhibition on physical severity of EAE, mice were administered biweekly injections of either D-2PMPA (20 mg/kg) or empty dendrimer vehicle (D-Veh) from the time of physical EAE disease onset. A free 20 mg/kg 2-PMPA control group dosed biweekly was not included in the present studies because the drug is cleared from circulation within six hours, and previous dose response studies showed that a minimal dose of 100 mg/kg was required for positive behavioral effects and alterations in brain NAAG levels [9]. Mice developed signs of EAE approximately 2 weeks post-immunization.…”

Section: D-2pmpa Administration Does Not Alter Physical Severity In Eae Mice But Selectively Improves Cognitive Functionmentioning

confidence: 99%

“…Previous studies have demonstrated a significant correlation between brain NAAG levels and cognition in MS patients, with higher NAAG levels associated with better cognitive function [8]. Furthermore, in an animal model of MS, the potent (IC 50 =300 pM) and selective GCPII inhibitor 2-(phosphonomethyl)-pentanedioic acid (2-PMPA) was shown to enhance brain NAAG levels and improve cognitive function [8,9]. Despite this strong therapeutic data, existing GCPII inhibitors have poor bioavailability and brain penetration and therefore are unsuitable for clinical translation to MS patients.…”

Section: Introductionmentioning

confidence: 99%

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Dendrimer-2PMPA selectively blocks upregulated microglial GCPII activity and improves cognition in a mouse model of multiple sclerosis

Hollinger¹,

Sharma²,

Tallon³

et al. 2022

Nanotheranostics

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Cognitive impairment is a common aspect of multiple sclerosis (MS) for which there are no treatments. Reduced brain N-acetylaspartylglutamate (NAAG) levels are linked to impaired cognition in various neurological diseases, including MS. NAAG levels are regulated by glutamate carboxypeptidase II (GCPII), which hydrolyzes the neuropeptide to N-acetyl-aspartate and glutamate. GCPII activity is upregulated multifold in microglia following neuroinflammation. Although several GCPII inhibitors, such as 2-PMPA, elevate brain NAAG levels and restore cognitive function in preclinical studies when given at high systemic doses or via direct brain injection, none are clinically available due to poor bioavailability and limited brain penetration. Hydroxyl-dendrimers have been successfully used to selectively deliver drugs to activated glia. Methods: We attached 2-PMPA to hydroxyl polyamidoamine (PAMAM) dendrimers (D-2PMPA) using a click chemistry approach. Cy5-labelled-D-2PMPA was used to visualize selective glial uptake in vitro and in vivo. D-2PMPA was evaluated for anti-inflammatory effects in LPS-treated glial cultures. In experimental autoimmune encephalomyelitis (EAE)-immunized mice, D-2PMPA was dosed biweekly starting at disease onset and cognition was assessed using the Barnes maze, and GCPII activity was measured in CD11b+ hippocampal cells. Results: D-2PMPA showed preferential uptake into microglia and robust anti-inflammatory activity, including elevations in NAAG, TGFβ, and mGluR3 in glial cultures. D-2PMPA significantly improved cognition in EAE mice, even though physical severity was unaffected. GCPII activity increased >20-fold in CD11b+ cells from EAE mice, which was significantly mitigated by D-2PMPA treatment. Conclusions: Hydroxyl dendrimers facilitate targeted drug delivery to activated microglia. These data support further development of D-2PMPA to attenuate elevated microglial GCPII activity and treat cognitive impairment in MS.

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“…Neuronal NAAG, its targeted astrocyte mGluR3, and astrocyte‐expressed NAAG peptidase have been associated with a wide range of human brain pathologies, and with the advent of a variety of mGluR3 agonists and antagonists and NAAG peptidase inhibitors researchers have been able to investigate their roles in animal models of human brain diseases . Although challenging, it is proposed that, when NAAG is measured separately from NAA, NAAG may demonstrate unique functional correlations and metabolite ratios different from those found with NAA and/or tNAA and thus provide important new insights into our basic understanding of brain function.…”

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confidence: 99%

Chasing N‐acetyl‐L‐aspartate, a shiny NMR object in the brain

Baslow

2018

NMR in Biomedicine

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N-acetyl-L-aspartate (NAA) is an important NMR object in the mammalian brain almost exclusively present in neurons. It is the most concentrated acetylated amino acid in human brain, at about 10mM, and one of the most concentrated amino acids present in neurons, at about 20mM. NAA has a strong proton MRS signature, at about 2.02 ppm, and is considered to be a specific marker for neuron density and/or viability and an indicator of neuronal loss in many human-brain pathologies. The "NAA' signal is used as a reference point in most brain MRS studies, and its ratio to other brain metabolites, many of which are present in different cells, indicates focal or global brain health in many medical conditions. NAA's high concentration in brain has prompted a search for its function. In 2000, its unique tricellular metabolism was documented. 1 In neurons, NAA is synthesized via NAA synthase 2 from acetyl coenzyme A, derived from the oxidation of glucose (Glc), and L-aspartate (Asp). The dipeptide N-acetylaspartylglutamate (NAAG) is then synthesized from NAA and L-glutamate (Glu) via NAAG synthase 3 ; this is the only known pathway for NAAG synthesis. Both NAA and NAAG turn over every 14 to16 hours, but, remarkably, neither substance can be catabolized by neurons. NAAG is released into extracellular fluid (ECF) and targeted to astrocytes, where it docks with the metabotropic Glu receptor 3 (mGluR3) and is cleaved into Glu and NAA by NAAG peptidase. 4 Astrocytes cannot hydrolyze NAA, so it is released into ECF, taken up by oligodendrocytes, and cleaved into acetate and Asp by aspartoacylase (ASPA), 5 and its products are completely metabolized. 6 While the biochemical pathways in the tricellular metabolism of NAA were already clear, its function and the specific physiological roles of cells in this sequence were not. In Figure 1, the biochemical and metabolic relationships of cells in the tricellular sequence are graphically illustrated. /journal/nbm 1 of 3 and both NAA and NAAG can be exported by neurons via the non-synaptic ATP-binding cassette subfamily C member 5 transporter of Glu conjugates and analogs. 7 mGluR3 is ubiquitous among cell types, and while NAAG can interact with other receptor types only astrocytes express NAAG peptidase, the enzyme that releases Glu from mGluR3-docked NAAG.Second, Canavan disease (CD) is a rare human inborn early-onset spongiform leukodystrophy in which oligodendrocyte ASPA is inactive, so NAA builds to high levels in brain ECF and is excreted in urine. Because NAA is not a neurotransmitter and can readily enter the vascular system for removal, it was proposed that CD was not a GM disease, but a specific WM demyelinating disease. In WM, it was posited that astrocyte-generated NAA from released NAAG built up in confined, dehydrated and lipid-rich spaces, which initiated an osmotic hydrostatic condition at nodes of Ranvier and led to the spongiform condition characterized by formation of inter-sheath vacuoles and the splitting of extant oligodendrocyte myelin sheaths surrounding axons. 13 In ...

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Dose-dependent inhibition of GCPII to prevent and treat cognitive impairment in the EAE model of multiple sclerosis

Cited by 21 publications

References 30 publications

Glutamine antagonism attenuates physical and cognitive deficits in a model of MS

Glutamine antagonism attenuates physical and cognitive deficits in a model of MS

Dendrimer-2PMPA selectively blocks upregulated microglial GCPII activity and improves cognition in a mouse model of multiple sclerosis

Chasing N‐acetyl‐L‐aspartate, a shiny NMR object in the brain

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