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Joyce MKP, Uchendu S, Arnsten AFT. Stress and Inflammation Target Dorsolateral Prefrontal Cortex Function: Neural Mechanisms Underlying Weakened Cognitive Control. Biol Psychiatry 2024:S0006-3223(24)01420-3. [PMID: 38944141 DOI: 10.1016/j.biopsych.2024.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 06/15/2024] [Accepted: 06/22/2024] [Indexed: 07/01/2024]
Abstract
Most mental disorders involve dysfunction of the dorsolateral prefrontal cortex (dlPFC), a recently evolved brain region that subserves working memory, abstraction, and the thoughtful regulation of attention, action, and emotion. For example, schizophrenia, depression, long COVID, and Alzheimer's disease are all associated with dlPFC dysfunction, with neuropathology often being focused in layer III. The dlPFC has extensive top-down projections, e.g., to the posterior association cortices to regulate attention and to the subgenual cingulate cortex via the rostral and medial PFC to regulate emotional responses. However, the dlPFC is particularly dependent on arousal state and is very vulnerable to stress and inflammation, which are etiological and/or exacerbating factors for most mental disorders. The cellular mechanisms by which stress and inflammation impact the dlPFC are a topic of current research and are summarized in this review. For example, the layer III dlPFC circuits that generate working memory-related neuronal firing have unusual neurotransmission, depending on NMDA receptor and nicotinic α7 receptor actions that are blocked under inflammatory conditions by kynurenic acid. These circuits also have unusual neuromodulation, with the molecular machinery to magnify calcium signaling in spines needed to support persistent firing, which must be tightly regulated to prevent toxic calcium actions. Stress rapidly weakens layer III connectivity by driving feedforward calcium-cAMP (cyclic adenosine monophosphate) opening of potassium channels on spines. This is regulated by postsynaptic noradrenergic α2A adrenergic receptor and mGluR3 (metabotropic glutamate receptor 3) signaling but dysregulated by inflammation and/or chronic stress exposure, which contribute to spine loss. Treatments that strengthen the dlPFC via pharmacological (the α2A adrenergic receptor agonist, guanfacine) or repetitive transcranial magnetic stimulation manipulation provide a rational basis for therapy.
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Affiliation(s)
- Mary Kate P Joyce
- Department of Neuroscience, Yale Medical School, New Haven, Connecticut
| | - Stacy Uchendu
- Department of Neuroscience, Yale Medical School, New Haven, Connecticut
| | - Amy F T Arnsten
- Department of Neuroscience, Yale Medical School, New Haven, Connecticut.
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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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Galindo AN, Frey Rubio DA, Hettiaratchi MH. Biomaterial strategies for regulating the neuroinflammatory response. MATERIALS ADVANCES 2024; 5:4025-4054. [PMID: 38774837 PMCID: PMC11103561 DOI: 10.1039/d3ma00736g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 04/07/2024] [Indexed: 05/24/2024]
Abstract
Injury and disease in the central nervous system (CNS) can result in a dysregulated inflammatory environment that inhibits the repair of functional tissue. Biomaterials present a promising approach to tackle this complex inhibitory environment and modulate the mechanisms involved in neuroinflammation to halt the progression of secondary injury and promote the repair of functional tissue. In this review, we will cover recent advances in biomaterial strategies, including nanoparticles, hydrogels, implantable scaffolds, and neural probe coatings, that have been used to modulate the innate immune response to injury and disease within the CNS. The stages of inflammation following CNS injury and the main inflammatory contributors involved in common neurodegenerative diseases will be discussed, as understanding the inflammatory response to injury and disease is critical for identifying therapeutic targets and designing effective biomaterial-based treatment strategies. Biomaterials and novel composites will then be discussed with an emphasis on strategies that deliver immunomodulatory agents or utilize cell-material interactions to modulate inflammation and promote functional tissue repair. We will explore the application of these biomaterial-based strategies in the context of nanoparticle- and hydrogel-mediated delivery of small molecule drugs and therapeutic proteins to inflamed nervous tissue, implantation of hydrogels and scaffolds to modulate immune cell behavior and guide axon elongation, and neural probe coatings to mitigate glial scarring and enhance signaling at the tissue-device interface. Finally, we will present a future outlook on the growing role of biomaterial-based strategies for immunomodulation in regenerative medicine and neuroengineering applications in the CNS.
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Affiliation(s)
- Alycia N Galindo
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon Eugene OR USA
| | - David A Frey Rubio
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon Eugene OR USA
| | - Marian H Hettiaratchi
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon Eugene OR USA
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR USA
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Datta D, Perone I, Wijegunawardana D, Liang F, Morozov YM, Arellano J, Duque A, Xie Z, van Dyck CH, Joyce MKP, Arnsten AFT. Nanoscale imaging of pT217-tau in aged rhesus macaque entorhinal and dorsolateral prefrontal cortex: Evidence of interneuronal trafficking and early-stage neurodegeneration. Alzheimers Dement 2024; 20:2843-2860. [PMID: 38445818 PMCID: PMC11032534 DOI: 10.1002/alz.13737] [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: 10/06/2023] [Revised: 01/04/2024] [Accepted: 01/16/2024] [Indexed: 03/07/2024]
Abstract
INTRODUCTION Tau phosphorylated at threonine-217 (pT217-tau) is a novel fluid-based biomarker that predicts onset of Alzheimer's disease (AD) symptoms, but little is known about how pT217-tau arises in the brain, as soluble pT217-tau is dephosphorylated post mortem in humans. METHODS We used multilabel immunofluorescence and immunoelectron microscopy to examine the subcellular localization of early-stage pT217-tau in entorhinal and prefrontal cortices of aged macaques with naturally occurring tau pathology and assayed pT217-tau levels in plasma. RESULTS pT217-tau was aggregated on microtubules within dendrites exhibiting early signs of degeneration, including autophagic vacuoles. It was also seen trafficking between excitatory neurons within synapses on spines, where it was exposed to the extracellular space, and thus accessible to cerebrospinal fluid (CSF)/blood. Plasma pT217-tau levels increased across the age span and thus can serve as a biomarker in macaques. DISCUSSION These data help to explain why pT217-tau predicts degeneration in AD and how it gains access to CSF and plasma to serve as a fluid biomarker.
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Affiliation(s)
- Dibyadeep Datta
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
- Department of PsychiatryYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Isabella Perone
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | | | - Feng Liang
- Department of AnesthesiaCritical Care and Pain MedicineMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Yury M. Morozov
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Jon Arellano
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Alvaro Duque
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Zhongcong Xie
- Department of AnesthesiaCritical Care and Pain MedicineMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | | | - Mary Kate P. Joyce
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Amy F. T. Arnsten
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
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Arnsten AFT, Wang M, D’Esposito M. Dynamic Network Connectivity: from monkeys to humans. Front Hum Neurosci 2024; 18:1353043. [PMID: 38384333 PMCID: PMC10879414 DOI: 10.3389/fnhum.2024.1353043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024] Open
Abstract
Human brain imaging research using functional MRI (fMRI) has uncovered flexible variations in the functional connectivity between brain regions. While some of this variability likely arises from the pattern of information flow through circuits, it may also be influenced by rapid changes in effective synaptic strength at the molecular level, a phenomenon called Dynamic Network Connectivity (DNC) discovered in non-human primate circuits. These neuromodulatory molecular mechanisms are found in layer III of the macaque dorsolateral prefrontal cortex (dlPFC), the site of the microcircuits shown by Goldman-Rakic to be critical for working memory. This research has shown that the neuromodulators acetylcholine, norepinephrine, and dopamine can rapidly change the strength of synaptic connections in layer III dlPFC by (1) modifying the depolarization state of the post-synaptic density needed for NMDA receptor neurotransmission and (2) altering the open state of nearby potassium channels to rapidly weaken or strengthen synaptic efficacy and the strength of persistent neuronal firing. Many of these actions involve increased cAMP-calcium signaling in dendritic spines, where varying levels can coordinate the arousal state with the cognitive state. The current review examines the hypothesis that some of the dynamic changes in correlative strength between cortical regions observed in human fMRI studies may arise from these molecular underpinnings, as has been seen when pharmacological agents or genetic alterations alter the functional connectivity of the dlPFC consistent with the macaque physiology. These DNC mechanisms provide essential flexibility but may also confer vulnerability to malfunction when dysregulated in cognitive disorders.
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Affiliation(s)
- Amy F. T. Arnsten
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Min Wang
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Mark D’Esposito
- Department of Psychology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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Datta D, Perone I, Morozov YM, Arellano J, Duque A, Rakic P, van Dyck CH, Arnsten AFT. Localization of PDE4D, HCN1 channels, and mGluR3 in rhesus macaque entorhinal cortex may confer vulnerability in Alzheimer's disease. Cereb Cortex 2023; 33:11501-11516. [PMID: 37874022 PMCID: PMC10724870 DOI: 10.1093/cercor/bhad382] [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: 05/01/2023] [Revised: 08/28/2023] [Accepted: 09/27/2023] [Indexed: 10/25/2023] Open
Abstract
Alzheimer's disease cortical tau pathology initiates in the layer II cell clusters of entorhinal cortex, but it is not known why these specific neurons are so vulnerable. Aging macaques exhibit the same qualitative pattern of tau pathology as humans, including initial pathology in layer II entorhinal cortex clusters, and thus can inform etiological factors driving selective vulnerability. Macaque data have already shown that susceptible neurons in dorsolateral prefrontal cortex express a "signature of flexibility" near glutamate synapses on spines, where cAMP-PKA magnification of calcium signaling opens nearby potassium and hyperpolarization-activated cyclic nucleotide-gated channels to dynamically alter synapse strength. This process is regulated by PDE4A/D, mGluR3, and calbindin, to prevent toxic calcium actions; regulatory actions that are lost with age/inflammation, leading to tau phosphorylation. The current study examined whether a similar "signature of flexibility" expresses in layer II entorhinal cortex, investigating the localization of PDE4D, mGluR3, and HCN1 channels. Results showed a similar pattern to dorsolateral prefrontal cortex, with PDE4D and mGluR3 positioned to regulate internal calcium release near glutamate synapses, and HCN1 channels concentrated on spines. As layer II entorhinal cortex stellate cells do not express calbindin, even when young, they may be particularly vulnerable to magnified calcium actions and ensuing tau pathology.
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Affiliation(s)
- Dibyadeep Datta
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Isabella Perone
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Yury M Morozov
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jon Arellano
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Alvaro Duque
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pasko Rakic
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | | | - Amy F T Arnsten
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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Datta D, Perone I, Wijegunawardana D, Liang F, Morozov YM, Arellano J, Duque A, Xie Z, van Dyck CH, Arnsten AFT. Nanoscale imaging of pT217-tau in aged rhesus macaque entorhinal and dorsolateral prefrontal cortex: Evidence of interneuronal trafficking and early-stage neurodegeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566046. [PMID: 37986900 PMCID: PMC10659394 DOI: 10.1101/2023.11.07.566046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
INTRODUCTION pT217-tau is a novel fluid-based biomarker that predicts onset of Alzheimer's disease (AD) symptoms, but little is known about how pT217-tau arises in brain, as soluble pT217-tau is dephosphorylated postmortem in humans. METHODS We utilized multi-label immunofluorescence and immunoelectron-microscopy to examine the subcellular localization of early-stage pT217-tau in entorhinal and prefrontal cortices of aged macaques with naturally-occurring tau pathology and assayed pT217-tau levels in plasma. RESULTS pT217-tau was aggregated on microtubules within dendrites exhibiting early signs of degeneration, including autophagic vacuoles. It was also seen trafficking between excitatory neurons within synapses on spines, where it was exposed to the extracellular space, and thus accessible to CSF/blood. Plasma pT217-tau levels increased across the age-span and thus can serve as a biomarker in macaques. DISCUSSION These data help to explain why pT217-tau predicts degeneration in AD and how it gains access to CSF and plasma to serve as a fluid biomarker.
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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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Bathla S, Datta D, Liang F, Barthelemy N, Wiseman R, Slusher BS, Asher J, Zeiss C, Ekanayake‐Alper D, Holden D, Terwilliger G, Duque A, Arellano J, van Dyck C, Bateman RJ, Xie Z, Nairn AC, Arnsten AFT. Chronic GCPII (glutamate-carboxypeptidase-II) inhibition reduces pT217Tau levels in the entorhinal and dorsolateral prefrontal cortices of aged macaques. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2023; 9:e12431. [PMID: 37915375 PMCID: PMC10617575 DOI: 10.1002/trc2.12431] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/28/2023] [Accepted: 09/30/2023] [Indexed: 11/03/2023]
Abstract
Introduction Current approaches for treating sporadic Alzheimer's disease (sAD) focus on removal of amyloid beta 1-42 (Aβ1-42) or phosphorylated tau, but additional strategies are needed to reduce neuropathology at earlier stages prior to neuronal damage. Longstanding data show that calcium dysregulation is a key etiological factor in sAD, and the cortical neurons most vulnerable to tau pathology show magnified calcium signaling, for example in dorsolateral prefrontal cortex (dlPFC) and entorhinal cortex (ERC). In primate dlPFC and ERC, type 3 metabotropic glutamate receptors (mGluR3s) are predominately post-synaptic, on spines, where they regulate cAMP-calcium signaling, a process eroded by inflammatory glutamate carboxypeptidase II (GCPII) actions. The current study tested whether enhancing mGluR3 regulation of calcium via chronic inhibition of GCPII would reduce tau hyperphosphorylation in aged macaques with naturally-occurring tau pathology. Methods Aged rhesus macaques were treated daily with the GCPII inhibitor, 2-MPPA (2-3-mercaptopropyl-penanedioic acid (2-MPPA)),Aged rhesus macaques were treated daily with the GCPII inhibitor, 2-MPPA (2-3-mercaptopropyl-penanedioic acid (2-MPPA)). Results Aged macaques that received 2-MPPA had significantly lower pT217Tau levels in dlPFC and ERC, and had lowered plasma pT217Tau levels from baseline. pT217Tau levels correlated significantly with GCPII activity in dlPFC. Both 2-MPPA- and vehicle-treated monkeys showed cognitive improvement; 2-MPPA had no apparent side effects. Exploratory CSF analyses indicated reduced pS202Tau with 2-MPPA administration, confirmed in dlPFC samples. Discussion These data provide proof-of-concept support that GCPII inhibition can reduce tau hyperphosphorylation in the primate cortices most vulnerable in sAD. GCPII inhibition may be particularly helpful in reducing the risk of sAD caused by inflammation. These data in nonhuman primates should encourage future research on this promising mechanism. Highlights Inflammation is a key driver of sporadic Alzheimer's disease.GCPII inflammatory signaling in brain decreases mGluR3 regulation of calcium.Chronic inhibition of GCPII inflammatory signaling reduced pT217Tau in aged monkeys.GCPII inhibition is a novel strategy to help prevent tau pathology at early stages.
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Affiliation(s)
- Shveta Bathla
- Departments of PsychiatryYale University School of MedicineNew HavenConnecticutUSA
| | - Dibyadeep Datta
- Departments of PsychiatryYale University School of MedicineNew HavenConnecticutUSA
- Departments of NeuroscienceYale University School of MedicineNew HavenConnecticutUSA
| | - Feng Liang
- Department of AnesthesiologyHarvard University School of MedicineBostonMassachusettsUSA
| | - Nicolas Barthelemy
- Department of NeurologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Robyn Wiseman
- Department of Neurology, Johns Hopkins University Drug DiscoveryJohns Hopkins School of MedicineBaltimoreMarylandUSA
| | - Barbara S Slusher
- Department of Neurology, Johns Hopkins University Drug DiscoveryJohns Hopkins School of MedicineBaltimoreMarylandUSA
| | - Jennifer Asher
- Departments of Comparative MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Caroline Zeiss
- Departments of Comparative MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Dil Ekanayake‐Alper
- Departments of Comparative MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Daniel Holden
- Departments of RadiologyYale University School of MedicineNew HavenConnecticutUSA
| | - Gordon Terwilliger
- Departments of Comparative MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Alvaro Duque
- Departments of NeuroscienceYale University School of MedicineNew HavenConnecticutUSA
| | - Jon Arellano
- Departments of NeuroscienceYale University School of MedicineNew HavenConnecticutUSA
| | - Christopher van Dyck
- Departments of PsychiatryYale University School of MedicineNew HavenConnecticutUSA
| | - Randall J. Bateman
- Departments of RadiologyYale University School of MedicineNew HavenConnecticutUSA
| | - Zhongcong Xie
- Departments of Comparative MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Angus C. Nairn
- Departments of PsychiatryYale University School of MedicineNew HavenConnecticutUSA
| | - Amy F. T. Arnsten
- Departments of NeuroscienceYale University School of MedicineNew HavenConnecticutUSA
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Datta D. Interrogating the Etiology of Sporadic Alzheimer's Disease Using Aging Rhesus Macaques: Cellular, Molecular, and Cortical Circuitry Perspectives. J Gerontol A Biol Sci Med Sci 2023; 78:1523-1534. [PMID: 37279946 PMCID: PMC10460555 DOI: 10.1093/gerona/glad134] [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: 11/16/2022] [Indexed: 06/08/2023] Open
Abstract
Aging is the most significant risk factor for neurodegenerative disorders such as Alzheimer's disease (AD) associated with profound socioeconomic and personal costs. Consequently, there is an urgent need for animal models that recapitulate the age-related spatial and temporal complexity and patterns of pathology identical to human AD. Our research in aging nonhuman primate models involving rhesus macaques has revealed naturally occurring amyloid and tau pathology, including the formation of amyloid plaques and neurofibrillary tangles comprising hyperphosphorylated tau. Moreover, rhesus macaques exhibit synaptic dysfunction in association cortices and cognitive impairments with advancing age, and thus can be used to interrogate the etiological mechanisms that generate neuropathological cascades in sporadic AD. Particularly, unique molecular mechanisms (eg, feedforward cyclic adenosine 3',5'-monophosphate [cAMP]-Protein kinase A (PKA)-calcium signaling) in the newly evolved primate dorsolateral prefrontal cortex are critical for persistent firing required for subserving higher-order cognition. For example, dendritic spines in primate dorsolateral prefrontal cortex contain a specialized repertoire of proteins to magnify feedforward cAMP-PKA-calcium signaling such as N-methyl-d-aspartic acid receptors and calcium channels on the smooth endoplasmic reticulum (eg, ryanodine receptors). This process is constrained by phosphodiesterases (eg, PDE4) that hydrolyze cAMP and calcium-buffering proteins (eg, calbindin) in the cytosol. However, genetic predispositions and age-related insults exacerbate feedforward cAMP-Protein kinase A-calcium signaling pathways that induce a myriad of downstream effects, including the opening of K+ channels to weaken network connectivity, calcium-mediated dysregulation of mitochondria, and activation of inflammatory cascades to eliminate synapses, thereby increasing susceptibility to atrophy. Therefore, aging rhesus macaques provide an invaluable model to explore novel therapeutic strategies in sporadic AD.
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Affiliation(s)
- Dibyadeep Datta
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
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Zhang F, Zhang Z, Alt J, Kambhampati SP, Sharma A, Singh S, Nance E, Thomas AG, Rojas C, Rais R, Slusher BS, Kannan RM, Kannan S. Dendrimer-enabled targeted delivery attenuates glutamate excitotoxicity and improves motor function in a rabbit model of cerebral palsy. J Control Release 2023; 358:27-42. [PMID: 37054778 PMCID: PMC10330216 DOI: 10.1016/j.jconrel.2023.04.017] [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: 11/11/2022] [Revised: 03/17/2023] [Accepted: 04/10/2023] [Indexed: 04/15/2023]
Abstract
Glutamate carboxypeptidase II (GCPII), localized on the surface of astrocytes and activated microglia, regulates extracellular glutamate concentration in the central nervous system (CNS). We have previously shown that GCPII is upregulated in activated microglia in the presence of inflammation. Inhibition of GCPII activity could reduce glutamate excitotoxicity, which may decrease inflammation and promote a 'normal' microglial phenotype. 2-(3-Mercaptopropyl) pentanedioic acid (2-MPPA) is the first GCPII inhibitor that underwent clinical trials. Unfortunately, immunological toxicities have hindered 2-MPPA clinical translation. Targeted delivery of 2-MPPA specifically to activated microglia and astrocytes that over-express GCPII has the potential to mitigate glutamate excitotoxicity and attenuate neuroinflammation. In this study, we demonstrate that 2-MPPA when conjugated to generation-4, hydroxyl-terminated polyamidoamine (PAMAM) dendrimers (D-2MPPA) localize specifically in activated microglia and astrocytes only in newborn rabbits with cerebral palsy (CP), not in controls. D-2MPPA treatment led to higher 2-MPPA levels in the injured brain regions compared to 2-MPPA treatment, and the extent of D-2MPPA uptake correlated with the injury severity. D-2MPPA was more efficacious than 2-MPPA in decreasing extracellular glutamate level in ex vivo brain slices of CP kits, and in increasing transforming growth factor beta 1 (TGF-β1) level in primary mixed glial cell cultures. A single systemic intravenous dose of D-2MPPA on postnatal day 1 (PND1) decreased microglial activation and resulted in a change in microglial morphology to a more ramified form along with amelioration of motor deficits by PND5. These results indicate that targeted dendrimer-based delivery specifically to activated microglia and astrocytes can improve the efficacy of 2-MPPA by attenuating glutamate excitotoxicity and microglial activation.
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Affiliation(s)
- Fan Zhang
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Zhi Zhang
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jesse Alt
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Siva P Kambhampati
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Anjali Sharma
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Sarabdeep Singh
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Elizabeth Nance
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ajit G Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Camilo Rojas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rana Rais
- 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
| | - Barbara S Slusher
- 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
| | - Rangaramanujam M Kannan
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
| | - Sujatha Kannan
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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12
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Fesharaki Zadeh A, Arnsten AFT, Wang M. Scientific Rationale for the Treatment of Cognitive Deficits from Long COVID. Neurol Int 2023; 15:725-742. [PMID: 37368329 PMCID: PMC10303664 DOI: 10.3390/neurolint15020045] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/26/2023] [Accepted: 05/11/2023] [Indexed: 06/28/2023] Open
Abstract
Sustained cognitive deficits are a common and debilitating feature of "long COVID", but currently there are no FDA-approved treatments. The cognitive functions of the dorsolateral prefrontal cortex (dlPFC) are the most consistently afflicted by long COVID, including deficits in working memory, motivation, and executive functioning. COVID-19 infection greatly increases kynurenic acid (KYNA) and glutamate carboxypeptidase II (GCPII) in brain, both of which can be particularly deleterious to PFC function. KYNA blocks both NMDA and nicotinic-alpha-7 receptors, the two receptors required for dlPFC neurotransmission, and GCPII reduces mGluR3 regulation of cAMP-calcium-potassium channel signaling, which weakens dlPFC network connectivity and reduces dlPFC neuronal firing. Two agents approved for other indications may be helpful in restoring dlPFC physiology: the antioxidant N-acetyl cysteine inhibits the production of KYNA, and the α2A-adrenoceptor agonist guanfacine regulates cAMP-calcium-potassium channel signaling in dlPFC and is also anti-inflammatory. Thus, these agents may be helpful in treating the cognitive symptoms of long COVID.
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Affiliation(s)
- Arman Fesharaki Zadeh
- Departments of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Departments of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Amy F. T. Arnsten
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA;
| | - Min Wang
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA;
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13
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Gori SS, Thomas AG, Pal A, Wiseman R, Ferraris DV, Gao RD, Wu Y, Alt J, Tsukamoto T, Slusher BS, Rais R. D-DOPA Is a Potent, Orally Bioavailable, Allosteric Inhibitor of Glutamate Carboxypeptidase II. Pharmaceutics 2022; 14:pharmaceutics14102018. [PMID: 36297453 PMCID: PMC9608075 DOI: 10.3390/pharmaceutics14102018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/14/2022] [Accepted: 09/19/2022] [Indexed: 12/02/2022] Open
Abstract
Glutamate carboxypeptidase-II (GCPII) is a zinc-dependent metalloenzyme implicated in numerous neurological disorders. The pharmacophoric requirements of active-site GCPII inhibitors makes them highly charged, manifesting poor pharmacokinetic (PK) properties. Herein, we describe the discovery and characterization of catechol-based inhibitors including L-DOPA, D-DOPA, and caffeic acid, with sub-micromolar potencies. Of these, D-DOPA emerged as the most promising compound, with good metabolic stability, and excellent PK properties. Orally administered D-DOPA yielded high plasma exposures (AUCplasma = 72.7 nmol·h/mL) and an absolute oral bioavailability of 47.7%. Unfortunately, D-DOPA brain exposures were low with AUCbrain = 2.42 nmol/g and AUCbrain/plasma ratio of 0.03. Given reports of isomeric inversion of D-DOPA to L-DOPA via D-amino acid oxidase (DAAO), we evaluated D-DOPA PK in combination with the DAAO inhibitor sodium benzoate and observed a >200% enhancement in both plasma and brain exposures (AUCplasma = 185 nmol·h/mL; AUCbrain = 5.48 nmol·h/g). Further, we demonstrated GCPII target engagement; orally administered D-DOPA with or without sodium benzoate caused significant inhibition of GCPII activity. Lastly, mode of inhibition studies revealed D-DOPA to be a noncompetitive, allosteric inhibitor of GCPII. To our knowledge, this is the first report of D-DOPA as a distinct scaffold for GCPII inhibition, laying the groundwork for future optimization to obtain clinically viable candidates.
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Affiliation(s)
- Sadakatali S. Gori
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Ajit G. Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Arindom Pal
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Robyn Wiseman
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Dana V. Ferraris
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Run-duo Gao
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Ying Wu
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Jesse Alt
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Takashi Tsukamoto
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Departments of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Correspondence: (B.S.S.); (R.R.)
| | - Rana Rais
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Correspondence: (B.S.S.); (R.R.)
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