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Wiseman RL, Bigos KL, Dastgheyb RM, Barker PB, Rubin LH, Slusher BS. Brain N -acetyl-aspartyl-glutamate is associated with cognitive function in older virally suppressed people with HIV. AIDS 2024; 38:1003-1011. [PMID: 38411600 PMCID: PMC11062820 DOI: 10.1097/qad.0000000000003871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 02/05/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
OBJECTIVES Cognitive impairment persists in virally suppressed people with HIV (VS-PWH) especially in higher order domains. One cortical circuit, linked to these domains, is regulated by N -acetyl-aspartyl glutamate (NAAG), the endogenous agonist of the metabotropic glutamate receptor 3. The enzyme glutamate carboxypeptidase II (GCPII) catabolizes NAAG and is upregulated in aging and disease. Inhibition of GCPII increases brain NAAG and improves learning and memory in rodent and primate models. DESIGN As higher order cognitive impairment is present in VS-PWH, and NAAG has not been investigated in earlier magnetic resonance spectroscopy studies (MRS), we investigated if brain NAAG levels measured by MRS were associated with cognitive function. METHODS We conducted a retrospective analysis of 7-Tesla MRS data from a previously published study on cognition in older VS-PWH. The original study did not separately quantify NAAG, therefore, work for this report focused on relationships between regional NAAG levels in frontal white matter (FWM), left hippocampus, left basal ganglia and domain-specific cognitive performance in 40 VS-PWH after adjusting for confounds. Participants were older than 50 years, negative for affective and neurologic disorders, and had no prior 3-month psychoactive-substance use. RESULTS Higher NAAG levels in FWM were associated with better attention/working memory. Higher left basal ganglia NAAG related to better verbal fluency. There was a positive relationship between hippocampal NAAG and executive function which lost significance after correction for confounds. CONCLUSION These data suggest brain NAAG serves as a biomarker of cognition in VS-PWH. Pharmacological modulation of brain NAAG warrants investigation as a therapeutic approach for cognitive deficits in VS-PWH.
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Affiliation(s)
- Robyn L. Wiseman
- Department of Pharmacology and Molecular Sciences
- Johns Hopkins Drug Discovery
- Department of Medicine, Division of Clinical Pharmacology
| | - Kristin L. Bigos
- Department of Pharmacology and Molecular Sciences
- Department of Medicine, Division of Clinical Pharmacology
- Department of Psychiatry and Behavioral Sciences
| | | | - Peter B. Barker
- Russell H. Morgan Department of Radiology and Radiological Sciences
| | - Leah H. Rubin
- Department of Psychiatry and Behavioral Sciences
- Department of Neurology
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health
| | - Barbara S. Slusher
- Department of Pharmacology and Molecular Sciences
- Johns Hopkins Drug Discovery
- Department of Medicine, Division of Clinical Pharmacology
- Department of Psychiatry and Behavioral Sciences
- Department of Neurology
- Department of Oncology
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Wang P, Huang Y, Sun B, Chen H, Ma Y, Liu Y, Yang T, Jin H, Qiao Y, Cao Y. Folic acid blocks ferroptosis induced by cerebral ischemia and reperfusion through regulating folate hydrolase transcriptional adaptive program. J Nutr Biochem 2024; 124:109528. [PMID: 37979712 DOI: 10.1016/j.jnutbio.2023.109528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 10/17/2023] [Accepted: 11/08/2023] [Indexed: 11/20/2023]
Abstract
Cerebral ischemia-reperfusion (I/R) injury is notably linked with folic acid (FA) deficiency. The aim of our investigation was to explore the effects and underlying mechanisms by which FA mitigates I/R, specifically through regulating the GCPII transcriptional adaptive program. Initially, we discovered that following cerebral I/R, levels of FA, methionine synthase (MTR), and methylenetetrahydrofolate reductase (MTHFR) were decreased, while GCPII expression was elevated. Secondly, administering FA could mitigate cognitive impairment and neuronal damage induced by I/R. Thirdly, the mechanism of FA supplementation involved suppressing the transcriptional factor Sp1, subsequently inhibiting GCPII transcription, reducing Glu content, obstructing cellular ferroptosis, and alleviating cerebral I/R injury. In summary, our data demonstrate that FA affords protection against cerebral I/R injury by inhibiting the GCPII transcriptional adaptive response. These findings unveil that targeting GCPII might be a viable therapeutic strategy for cerebral I/R.
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Affiliation(s)
- Peng Wang
- Department of Physiology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - Yangyang Huang
- Department of Pediatrics, Daqing People's Hospital, Daqing, Heilongjiang, China
| | - Buxun Sun
- Department of Physiology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - Hongpeng Chen
- Department of Physiology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - YiFan Ma
- Department of Physiology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - Yuhang Liu
- Department of Physiology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - Tao Yang
- Department of Pharmacology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China
| | - Hongbo Jin
- Department of Physiology, Harbin Medical University, Harbin, Heilongjiang, China.
| | - Yuandong Qiao
- Department of Genetics, Harbin Medical University-Daqing, Daqing, Heilongjiang, China.
| | - Yongggang Cao
- Department of Pharmacology, Harbin Medical University-Daqing, Daqing, Heilongjiang, China.
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3
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Arnsten AFT, Ishizawa Y, Xie Z. Scientific rationale for the use of α2A-adrenoceptor agonists in treating neuroinflammatory cognitive disorders. Mol Psychiatry 2023; 28:4540-4552. [PMID: 37029295 PMCID: PMC10080530 DOI: 10.1038/s41380-023-02057-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 04/09/2023]
Abstract
Neuroinflammatory disorders preferentially impair the higher cognitive and executive functions of the prefrontal cortex (PFC). This includes such challenging disorders as delirium, perioperative neurocognitive disorder, and the sustained cognitive deficits from "long-COVID" or traumatic brain injury. There are no FDA-approved treatments for these symptoms; thus, understanding their etiology is important for generating therapeutic strategies. The current review describes the molecular rationale for why PFC circuits are especially vulnerable to inflammation, and how α2A-adrenoceptor (α2A-AR) actions throughout the nervous and immune systems can benefit the circuits in PFC needed for higher cognition. The layer III circuits in the dorsolateral PFC (dlPFC) that generate and sustain the mental representations needed for higher cognition have unusual neurotransmission and neuromodulation. They are wholly dependent on NMDAR neurotransmission, with little AMPAR contribution, and thus are especially vulnerable to kynurenic acid inflammatory signaling which blocks NMDAR. Layer III dlPFC spines also have unusual neuromodulation, with cAMP magnification of calcium signaling in spines, which opens nearby potassium channels to rapidly weaken connectivity and reduce neuronal firing. This process must be tightly regulated, e.g. by mGluR3 or α2A-AR on spines, to prevent loss of firing. However, the production of GCPII inflammatory signaling reduces mGluR3 actions and markedly diminishes dlPFC network firing. Both basic and clinical studies show that α2A-AR agonists such as guanfacine can restore dlPFC network firing and cognitive function, through direct actions in the dlPFC, but also by reducing the activity of stress-related circuits, e.g. in the locus coeruleus and amygdala, and by having anti-inflammatory actions in the immune system. This information is particularly timely, as guanfacine is currently the focus of large clinical trials for the treatment of delirium, and in open label studies for the treatment of cognitive deficits from long-COVID.
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Affiliation(s)
- Amy F T Arnsten
- Department Neuroscience, Yale University School of Medicine, New Haven, CT, 056510, USA.
| | - Yumiko Ishizawa
- Department Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Zhongcong Xie
- Department Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
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4
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Peters DE, Norris LD, Tenora L, Šnajdr I, Ponti AK, Zhu X, Sakamoto S, Veeravalli V, Pradhan M, Alt J, Thomas AG, Majer P, Rais R, McDonald C, Slusher BS. A gut-restricted glutamate carboxypeptidase II inhibitor reduces monocytic inflammation and improves preclinical colitis. Sci Transl Med 2023; 15:eabn7491. [PMID: 37556558 PMCID: PMC10661206 DOI: 10.1126/scitranslmed.abn7491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/21/2023] [Indexed: 08/11/2023]
Abstract
There is an urgent need to develop therapeutics for inflammatory bowel disease (IBD) because up to 40% of patients with moderate-to-severe IBD are not adequately controlled with existing drugs. Glutamate carboxypeptidase II (GCPII) has emerged as a promising therapeutic target. This enzyme is minimally expressed in normal ileum and colon, but it is markedly up-regulated in biopsies from patients with IBD and preclinical colitis models. Here, we generated a class of GCPII inhibitors designed to be gut-restricted for oral administration, and we interrogated efficacy and mechanism using in vitro and in vivo models. The lead inhibitor, (S)-IBD3540, was potent (half maximal inhibitory concentration = 4 nanomolar), selective, gut-restricted (AUCcolon/plasma > 50 in mice with colitis), and efficacious in acute and chronic rodent colitis models. In dextran sulfate sodium-induced colitis, oral (S)-IBD3540 inhibited >75% of colon GCPII activity, dose-dependently improved gross and histologic disease, and markedly attenuated monocytic inflammation. In spontaneous colitis in interleukin-10 (IL-10) knockout mice, once-daily oral (S)-IBD3540 initiated after disease onset improved disease, normalized colon histology, and attenuated inflammation as evidenced by reduced fecal lipocalin 2 and colon pro-inflammatory cytokines/chemokines, including tumor necrosis factor-α and IL-17. Using primary human colon epithelial air-liquid interface monolayers to interrogate the mechanism, we further found that (S)-IBD3540 protected against submersion-induced oxidative stress injury by decreasing barrier permeability, normalizing tight junction protein expression, and reducing procaspase-3 activation. Together, this work demonstrated that local inhibition of dysregulated gastrointestinal GCPII using the gut-restricted, orally active, small-molecule (S)-IBD3540 is a promising approach for IBD treatment.
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Affiliation(s)
- Diane E. Peters
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lauren D. Norris
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lukáš Tenora
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 160 00 Prague, Czechia
| | - Ivan Šnajdr
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 160 00 Prague, Czechia
| | - András K. Ponti
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Xiaolei Zhu
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shinji Sakamoto
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Vijayabhaskar Veeravalli
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Manisha Pradhan
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jesse Alt
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ajit G. Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 160 00 Prague, Czechia
| | - Rana Rais
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christine McDonald
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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Beresewicz-Haller M. Hippocampal region-specific endogenous neuroprotection as an approach in the search for new neuroprotective strategies in ischemic stroke. Fiction or fact? Neurochem Int 2023; 162:105455. [PMID: 36410452 DOI: 10.1016/j.neuint.2022.105455] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/03/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Ischemic stroke is the leading cause of death and long-term disability worldwide, and, while considerable progress has been made in understanding its pathophysiology, the lack of effective treatments remains a major concern. In that context, receiving more and more consideration as a promising therapeutic method is the activation of natural adaptive mechanisms (endogenous neuroprotection) - an approach that seeks to enhance and/or stimulate the endogenous processes of plasticity and protection of the neuronal system that trigger the brain's intrinsic capacity for self-defence. Ischemic preconditioning is a classic example of endogenous neuroprotection, being the process by which one or more brief, non-damaging episodes of ischemia-reperfusion (I/R) induce tissue resistance to subsequent prolonged, damaging ischemia. Another less-known example is resistance to an I/R episode mounted by the hippocampal region consisting of CA2, CA3, CA4 and the dentate gyrus (here abbreviated to CA2-4, DG). This can be contrasted with the ischemia-vulnerable CA1 region. There is not yet a good understanding of these different sensitivities of the hippocampal regions, and hence of the endogenous neuroprotection characteristic of CA2-4, DG. However, this region is widely reported to have properties distinct from CA1, and capable of generating resistance to an I/R episode. These include activation of neurotrophic and neuroprotective factors, greater activation of anti-excitotoxic and anti-oxidant mechanisms, increased plasticity potential, a greater energy reserve and improved mitochondrial function. This review seeks to summarize properties of CA2-4, DG in the context of endogenous neuroprotection, and then to assess the potential utility of these properties to therapeutic approaches. In so doing, it appears to represent the first such addressing of the issue of ischemia resistance attributable to CA2-4, DG.
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6
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Li K, Lu M, Cui M, Wang X, Zheng Y. The regulatory role of NAAG-mGluR3 signaling on cortical synaptic plasticity after hypoxic ischemia. Cell Commun Signal 2022; 20:55. [PMID: 35443669 PMCID: PMC9022257 DOI: 10.1186/s12964-022-00866-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/25/2022] [Indexed: 11/14/2022] Open
Abstract
Background Synapses can adapt to changes in the intracerebral microenvironment by regulation of presynaptic neurotransmitter release and postsynaptic neurotransmitter receptor expression following hypoxic ischemia (HI) injury. The peptide neurotransmitter N-acetylaspartylglutamate (NAAG) exerts a protective effect on neurons after HI and may be involved in maintaining the function of synaptic networks. In this study, we investigated the changes in the expression of NAAG, glutamic acid (Glu) and metabotropic glutamate receptors (mGluRs), as well as the dynamic regulation of neurotransmitters in the brain after HI, and assessed their effects on synaptic plasticity of the cerebral cortex. Methods Thirty-six Yorkshire newborn pigs (3-day-old, males, 1.0–1.5 kg) were selected and randomly divided into normal saline (NS) group (n = 18) and glutamate carboxypeptidase II inhibition group (n = 18), both groups were divided into control group, 0–6 h, 6–12 h, 12–24 h, 24–48 h and 48–72 h groups (all n = 3) according to different post-HI time. The content of Glu and NAAG after HI injury were detected by 1H-MRS scanning, immunofluorescence staining of mGluRs, synaptophysin (syph) along with postsynaptic density protein-95 (PSD95) and transmission electron microscopy were performed. ANOVA, Tukey and LSD test were used to compare the differences in metabolite and protein expression levels among subgroups. Correlation analysis was performed using Pearson analysis with a significance level of α = 0.05. Results We observed that the NAAG and mGluR3 expression levels in the brain increased and then decreased after HI and was significantly higher in the 12–24 h (P < 0.05, Tukey test). There was a significant positive correlation between Glu content and the expression of mGluR1/mGluR5 after HI with r = 0.521 (P = 0.027) and r = 0.477 (P = 0.045), respectively. NAAG content was significantly and positively correlated with the level of mGluR3 expression (r = 0.472, P = 0.048). When hydrolysis of NAAG was inhibited, the expression of synaptic protein PSD95 and syph decreased significantly. Conclusions After 12–24 h of HI injury, there was a one-time elevation in NAAG levels, which was consistent with the corresponding mGluR3 receptor expression trend; the NAAG maintains cortical synaptic plasticity and neurotransmitter homeostasis by inhibiting presynaptic glutamate vesicle release, regulating postsynaptic density proteins and postsynaptic receptor expression after pathway activation. Video abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00866-8.
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Affiliation(s)
- Kexin Li
- Department of Radiology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004, People's Republic of China
| | - Meng Lu
- Department of Radiology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004, People's Republic of China
| | - Mengxu Cui
- Department of Radiology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004, People's Republic of China
| | - Xiaoming Wang
- Department of Radiology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004, People's Republic of China.
| | - Yang Zheng
- Department of Radiology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Heping District, Shenyang, 110004, People's Republic of China.
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7
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Morland C, Nordengen K. N-Acetyl-Aspartyl-Glutamate in Brain Health and Disease. Int J Mol Sci 2022; 23:ijms23031268. [PMID: 35163193 PMCID: PMC8836185 DOI: 10.3390/ijms23031268] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 02/04/2023] Open
Abstract
N-acetyl-aspartyl-glutamate (NAAG) is the most abundant dipeptide in the brain, where it acts as a neuromodulator of glutamatergic synapses by activating presynaptic metabotropic glutamate receptor 3 (mGluR3). Recent data suggest that NAAG is selectively localized to postsynaptic dendrites in glutamatergic synapses and that it works as a retrograde neurotransmitter. NAAG is released in response to glutamate and provides the postsynaptic neuron with a feedback mechanisms to inhibit excessive glutamate signaling. A key regulator of synaptically available NAAG is rapid degradation by the extracellular enzyme glutamate carboxypeptidase II (GCPII). Increasing endogenous NAAG—for instance by inhibiting GCPII—is a promising treatment option for many brain disorders where glutamatergic excitotoxicity plays a role. The main effect of NAAG occurs through increased mGluR3 activation and thereby reduced glutamate release. In the present review, we summarize the transmitter role of NAAG and discuss the involvement of NAAG in normal brain physiology. We further present the suggested roles of NAAG in various neurological and psychiatric diseases and discuss the therapeutic potential of strategies aiming to enhance NAAG levels.
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Affiliation(s)
- Cecilie Morland
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, The Faculty of Mathematics and Natural Sciences, University of Oslo, 1068 Oslo, Norway
- Correspondence: (C.M.); (K.N.); Tel.: +47-22844937; (C.M.); +47-23073580 (K.N.)
| | - Kaja Nordengen
- Department of Neurology, Oslo University Hospital, 0424 Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway
- Correspondence: (C.M.); (K.N.); Tel.: +47-22844937; (C.M.); +47-23073580 (K.N.)
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8
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Yang S, Datta D, Elizabeth Woo, Duque A, Morozov YM, Arellano J, Slusher BS, Wang M, Arnsten AFT. Inhibition of glutamate-carboxypeptidase-II in dorsolateral prefrontal cortex: potential therapeutic target for neuroinflammatory cognitive disorders. Mol Psychiatry 2022; 27:4252-4263. [PMID: 35732693 PMCID: PMC9718677 DOI: 10.1038/s41380-022-01656-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/27/2022] [Indexed: 02/07/2023]
Abstract
Glutamate carboxypeptidase-II (GCPII) expression in brain is increased by inflammation, e.g. by COVID19 infection, where it reduces NAAG stimulation of metabotropic glutamate receptor type 3 (mGluR3). GCPII-mGluR3 signaling is increasingly linked to higher cognition, as genetic alterations that weaken mGluR3 or increase GCPII signaling are associated with impaired cognition in humans. Recent evidence from macaque dorsolateral prefrontal cortex (dlPFC) shows that mGluR3 are expressed on dendritic spines, where they regulate cAMP-PKA opening of potassium (K+) channels to enhance neuronal firing during working memory. However, little is known about GCPII expression and function in the primate dlPFC, despite its relevance to inflammatory disorders. The present study used multiple label immunofluorescence and immunoelectron microscopy to localize GCPII in aging macaque dlPFC, and examined the effects of GCPII inhibition on dlPFC neuronal physiology and working memory function. GCPII was observed in astrocytes as expected, but also on neurons, including extensive expression in dendritic spines. Recordings in dlPFC from aged monkeys performing a working memory task found that iontophoresis of the GCPII inhibitors 2-MPPA or 2-PMPA markedly increased working memory-related neuronal firing and spatial tuning, enhancing neural representations. These beneficial effects were reversed by an mGluR2/3 antagonist, or by a cAMP-PKA activator, consistent with mGluR3 inhibition of cAMP-PKA-K+ channel signaling. Systemic administration of the brain penetrant inhibitor, 2-MPPA, significantly improved working memory performance without apparent side effects, with largest effects in the oldest monkeys. Taken together, these data endorse GCPII inhibition as a potential strategy for treating cognitive disorders associated with aging and/or neuroinflammation.
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Affiliation(s)
- Shengtao Yang
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Dibyadeep Datta
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Department Psychiatry, Yale University School of Medicine, New Haven, CT USA
| | - Elizabeth Woo
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Alvaro Duque
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Yury M. Morozov
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Jon Arellano
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Barbara S. Slusher
- grid.21107.350000 0001 2171 9311Department Neurology and Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD USA
| | - Min Wang
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Amy F. T. Arnsten
- grid.47100.320000000419368710Department Neuroscience, Yale University School of Medicine, New Haven, CT USA
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9
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Datta D, Leslie SN, Woo E, Amancharla N, Elmansy A, Lepe M, Mecca AP, Slusher BS, Nairn AC, Arnsten AFT. Glutamate Carboxypeptidase II in Aging Rat Prefrontal Cortex Impairs Working Memory Performance. Front Aging Neurosci 2021; 13:760270. [PMID: 34867287 PMCID: PMC8634091 DOI: 10.3389/fnagi.2021.760270] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/28/2021] [Indexed: 11/29/2022] Open
Abstract
Glutamate carboxypeptidase II (GCPII) expression in brain is increased by inflammation, and reduces NAAG (N-acetyl aspartyl glutamate) stimulation of mGluR3 signaling. Genetic insults in this signaling cascade are increasingly linked to cognitive disorders in humans, where increased GCPII and or decreased NAAG-mGluR3 are associated with impaired prefrontal cortical (PFC) activation and cognitive impairment. As aging is associated with increased inflammation and PFC cognitive deficits, the current study examined GCPII and mGluR3 expression in the aging rat medial PFC, and tested whether GCPII inhibition with 2-(3-mercaptopropyl) pentanedioic acid (2-MPPA) would improve working memory performance. We found that GCPII protein was expressed on astrocytes and some microglia as expected from previous studies, but was also prominently expressed on neurons, and showed increased levels with advancing age. Systemic administration of the GCPII inhibitor, 2-MPPA, improved working memory performance in young and aged rats, and also improved performance after local infusion into the medial PFC. As GCPII inhibitors are well-tolerated, they may provide an important new direction for treatment of cognitive disorders associated with aging and/or inflammation.
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Affiliation(s)
- Dibyadeep Datta
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Shannon N Leslie
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Elizabeth Woo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Nishita Amancharla
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Ayah Elmansy
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Miguel Lepe
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Adam P Mecca
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Barbara S Slusher
- Department of Neurology and Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Angus C Nairn
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Amy F T Arnsten
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
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10
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Nordengen K, Morland C, Slusher BS, Gundersen V. Dendritic Localization and Exocytosis of NAAG in the Rat Hippocampus. Cereb Cortex 2021; 30:1422-1435. [PMID: 31504271 PMCID: PMC7132944 DOI: 10.1093/cercor/bhz176] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 07/04/2019] [Accepted: 07/04/2019] [Indexed: 12/16/2022] Open
Abstract
While a lot is known about classical, anterograde neurotransmission, less is known about the mechanisms and molecules involved in retrograde neurotransmission. Our hypothesis is that N-acetylaspartylglutamate (NAAG), the most abundant dipeptide in the brain, may act as a retrograde transmitter in the brain. NAAG was predominantly localized in dendritic compartments of glutamatergic synapses in the intact hippocampus, where it was present in close proximity to synaptic-like vesicles. In acute hippocampal slices, NAAG was depleted from postsynaptic dendritic elements during neuronal stimulation induced by depolarizing concentrations of potassium or by exposure to glutamate receptor (GluR) agonists. The depletion was completely blocked by botulinum toxin B and strictly dependent on extracellular calcium, indicating exocytotic release. In contrast, there were low levels of NAAG and no effect by depolarization or GluR agonists in presynaptic glutamatergic terminals or GABAergic pre- and postsynaptic elements. Together these data suggest a possible role for NAAG as a retrograde signaling molecule at glutamatergic synapses via exocytotic release.
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Affiliation(s)
- K Nordengen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo NO-0317, Norway.,Department of Neurology, Akershus University Hospital, Lørenskog N-1478, Norway
| | - C Morland
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo NO-0317, Norway.,Department of Pharmaceutical Biosciences, Institute of Pharmacy, University of Oslo, Oslo NO-0317, Norway
| | - B S Slusher
- Department of Neurology and Johns Hopkins Drug Discovery, John Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - V Gundersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo NO-0317, Norway.,Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo N-0424, Norway.,Department of Neurology, Institute of Clinical Medicine, University of Oslo, Oslo NO-0317, Norway
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11
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Bratek - Gerej E, Bronisz A, Ziembowicz A, Salinska E. Pretreatment with mGluR2 or mGluR3 Agonists Reduces Apoptosis Induced by Hypoxia-Ischemia in Neonatal Rat Brains. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8848015. [PMID: 33763176 PMCID: PMC7963909 DOI: 10.1155/2021/8848015] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/04/2021] [Accepted: 02/23/2021] [Indexed: 11/17/2022]
Abstract
Hypoxia-ischemia (HI) in an immature brain results in energy depletion and excessive glutamate release resulting in excitotoxicity and oxidative stress. An increase in reactive oxygen species (ROS) production induces apoptotic processes resulting in neuronal death. Activation of group II mGluR was shown to prevent neuronal damage after HI. The application of agonists of mGluR3 (N-acetylaspartylglutamate; NAAG) or mGluR2 (LY379268) inhibits the release of glutamate and reduces neurodegeneration in a neonatal rat model of HI, although the exact mechanism is not fully recognized. In the present study, the effects of NAAG (5 mg/kg) and LY379268 (5 mg/kg) application (24 h or 1 h before experimental birth asphyxia) on apoptotic processes as the potential mechanism of neuroprotection in 7-day-old rats were investigated. Intraperitoneal application of NAAG or LY379268 at either time point before HI significantly reduced the number of TUNEL-positive cells in the CA1 region of the ischemic brain hemisphere. Both agonists reduced expression of the proapoptotic Bax protein and increased expression of Bcl-2. Decreases in HI-induced caspase-9 and caspase-3 activity were also observed. Application of NAAG or LY379268 24 h or 1 h before HI reduced HIF-1α formation likely by reducing ROS levels. It was shown that LY379268 concentration remains at a level that is required for activation of mGluR2 for up to 24 h; however, NAAG is quickly metabolized by glutamate carboxypeptidase II (GCPII) into glutamate and N-acetyl-aspartate. The observed effect of LY379268 application 24 h or 1 h before HI is connected with direct activation of mGluR2 and inhibition of glutamate release. Based on the data presented in this study and on our previous findings, we conclude that the neuroprotective effect of NAAG applied 1 h before HI is most likely the result of a combination of mGluR3 and NMDA receptor activation, whereas the beneficial effects of NAAG pretreatment 24 h before HI can be explained by the activation of NMDA receptors and induction of the antioxidative/antiapoptotic defense system triggered by mild excitotoxicity in neurons. This response to NAAG pretreatment is consistent with the commonly accepted mechanism of preconditioning.
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Affiliation(s)
- Ewelina Bratek - Gerej
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Bronisz
- Tumor Microenvironment Laboratory, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Apolonia Ziembowicz
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Elzbieta Salinska
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
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Neale JH, Yamamoto T. N-acetylaspartylglutamate (NAAG) and glutamate carboxypeptidase II: An abundant peptide neurotransmitter-enzyme system with multiple clinical applications. Prog Neurobiol 2019; 184:101722. [PMID: 31730793 DOI: 10.1016/j.pneurobio.2019.101722] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/24/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022]
Abstract
N-Acetylaspartylglutamate (NAAG) is the third most prevalent neurotransmitter in the mammalian nervous system, yet its therapeutic potential is only now being fully recognized. Drugs that inhibit the inactivation of NAAG by glutamate carboxypeptidase II (GCPII) increase its extracellular concentration and its activation of its receptor, mGluR3. These drugs warrant attention, as they are effective in animal models of several clinical disorders including stroke, traumatic brain injury and schizophrenia. In inflammatory and neuropathic pain studies, GCPII inhibitors moderated both the primary and secondary pain responses when given systemically, locally or in brain regions associated with the pain perception pathway. The finding that GCPII inhibition also moderated the motor and cognitive effects of ethanol intoxication led to the discovery of their procognitive efficacy in long-term memory tests in control mice and in short-term memory in a mouse model of Alzheimer's disease. NAAG and GCPII inhibitors respectively reduce cocaine self-administration and the rewarding effects of a synthetic stimulant. Most recently, GCPII inhibition also has been reported to be efficacious in a model of inflammatory bowel disease. GCPII was first discovered as a protein expressed by and released from metastatic prostate cells where it is known as prostate specific membrane antigen (PSMA). GCPII inhibitors with high affinity for this protein have been developed as prostate imaging and radiochemical therapies for prostate cancer. Taken together, these data militate in favor of the development and application of GCPII inhibitors in more advanced preclinical research as a prelude to clinical trials.
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Affiliation(s)
- Joseph H Neale
- Department of Biology, Georgetown University, 37(th) and O Sts., NW, Washington, DC, 20057, USA.
| | - Tatsuo Yamamoto
- Dept. of Anesthesiology, Kumamoto University., Kumamoto, Japan
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