The neutrophil enzyme myeloperoxidase directly modulates neuronal response after subarachnoid hemorrhage, a sterile injury model

2020 ◽  
Author(s):  
Aminata P. Coulibaly ◽  
Pinar Pezuk ◽  
Paul Varghese ◽  
William Gartman ◽  
Danielle Triebwasser ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cognitive Deficits ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neuronal Response ◽  
Neutrophil Infiltration ◽  
Brain Parenchyma ◽  
Biologically Active ◽  
Cns Injury ◽  
And Function ◽  
The Brain

Abstract Background: Aneurysmal subarachnoid hemorrhage (SAH) is associated with the development of delayed cognitive deficits. Neutrophil infiltration into the central nervous system (CNS) is linked to the development of these deficits after SAH. It is however unclear how neutrophil activity, direct or indirect, influences CNS function in SAH. As such, the present project aims to elucidate neutrophil factors and mechanisms mediating CNS injury and cognitive deficits after SAH. Methods: Using a murine model of SAH and mice deficient in neutrophil effector functions, we determined which neutrophil effector function is critical to the development of deficits after SAH. Also, in vitro techniques were used to elucidate whether neutrophils directly or indirectly affect neuronal function after SAH. Results: Our results show that following SAH, neutrophils infiltrate the meninges, and not the brain parenchyma. Mice lacking functional myeloperoxidase (MPO KO), a neutrophil enzyme, lack both the meningeal neutrophil infiltration and the cognitive deficits associated with SAH. The re-introduction of biologically active MPO, and its substrate hydrogen peroxide, to the cerebrospinal fluid of MPO KO mice at the time of hemorrhage restores the spatial memory deficit observed after SAH. Furthermore, MPO directly affects the function of both primary neurons and astrocytes in culture. Neurons exposed to MPO and its substrate show decreased calcium activity at baseline and after stimulation with potassium chloride. In addition, MPO and its substrate lead to significant astrocyte loss in culture, phenocopying a result observed in the brain after SAH. Conclusions: These results implicate MPO as a mediator of neuronal dysfunction in SAH through direct effect on both neurons and astrocytes. Finally, these results show that, in SAH, the activity of innate immune cells in the meninges can modulate the activity and function of the underlying brain tissue.

The neutrophil enzyme myeloperoxidase modulates neuronal response after subarachnoid hemorrhage, a sterile injury model

2020 ◽  
Author(s):  
Aminata P. Coulibaly ◽  
Pinar Pezuk ◽  
Paul Varghese ◽  
William Gartman ◽  
Danielle Triebwasser ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cognitive Deficits ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neuronal Response ◽  
Neutrophil Infiltration ◽  
Brain Parenchyma ◽  
Biologically Active ◽  
Cns Injury ◽  
The Brain

Abstract Background: Aneurysmal subarachnoid hemorrhage (SAH) is associated with the development of delayed cognitive deficits. Neutrophil infiltration into the central nervous system (CNS) is linked to the development of these deficits after SAH. It is however unclear how neutrophil activity influences CNS function in SAH. As such, the present project aims to elucidate neutrophil factors and mechanisms mediating CNS injury and cognitive deficits after SAH. Methods: Using a murine model of SAH and mice deficient in neutrophil effector functions, we determined which neutrophil effector function is critical to the development of deficits after SAH. Also, in vitro techniques were used to elucidate how neutrophils affect cellular function of neurons and glia after SAH. Results: Our results show that following SAH, neutrophils infiltrate the meninges, and not the brain parenchyma. Mice lacking functional myeloperoxidase (MPO KO), a neutrophil enzyme, lack both the meningeal neutrophil infiltration and the cognitive deficits associated with SAH. The re-introduction of biologically active MPO, and its substrate hydrogen peroxide, to the cerebrospinal fluid of MPO KO mice at the time of hemorrhage restores the spatial memory deficit observed after SAH. Furthermore, in culture, MPO affects the function of both primary neurons and astrocytes, though not microglia. Neurons exposed to MPO and its substrate show decreased calcium activity at baseline and after stimulation with potassium chloride. In addition, MPO and its substrate lead to significant astrocyte loss in culture, phenocopying a result observed in the brain after SAH. Conclusions: These results implicate MPO as a mediator of neuronal dysfunction in SAH through their effect on both neurons and astrocytes. Finally, these results show that, in SAH, the activity of innate immune cells in the meninges can modulate the activity and function of the underlying brain tissue.

scholarly journals The neutrophil enzyme myeloperoxidase directly modulates neuronal response after subarachnoid hemorrhage, a sterile injury model

2019 ◽  
Author(s):  
Aminata P. Coulibaly ◽  
Pinar Pezuk ◽  
Paul Varghese ◽  
William Gartman ◽  
Danielle Triebwasser ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cognitive Deficits ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neuronal Response ◽  
Neutrophil Infiltration ◽  
Cell Types ◽  
Brain Parenchyma ◽  
Cerebral Injury ◽  
Biologically Active ◽  
The Brain

AbstractNeutrophil infiltration into the central nervous system (CNS) after injury is associated with cognitive deficits. Using a murine model of aneurysmal subarachnoid hemorrhage (SAH), we elucidate the location and mode of action of neutrophils in the CNS. Following SAH, neutrophils infiltrate the meninges, and not the brain parenchyma. Mice lacking functional myeloperoxidase (MPO KO), a neutrophil enzyme, lack both the meningeal neutrophil infiltration and the cognitive deficits associated with delayed cerebral injury from SAH. The re-introduction of biologically active MPO, and its substrate hydrogen peroxide, to the cerebrospinal fluid of MPO KO mice at the time of hemorrhage restores the spatial memory deficit observed after SAH. This implicates MPO as a mediator of neuronal dysfunction in SAH. Using primary neuronal and astrocyte cultures, we demonstrate that MPO directly affects the function of both cell types. Neurons exposed to MPO and its substrate show decreased calcium activity at baseline and after stimulation with potassium chloride. In addition, MPO and its substrate lead to significant astrocyte loss in culture, a result observed in the brain after SAH as well. These results show that, in SAH, the activity of innate immune cells in the meninges modulates the activity and function of the underlying brain tissue.

Neutrophil Enzyme Myeloperoxidase Modulates Neuronal Response in a Model of Subarachnoid Hemorrhage by Venous Injury

Stroke ◽  
2021 ◽  
Vol 52 (10) ◽  
pp. 3374-3384
Author(s):  
Aminata P. Coulibaly ◽  
Pinar Pezuk ◽  
Paul Varghese ◽  
William Gartman ◽  
Danielle Triebwasser ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Subarachnoid Hemorrhage ◽  
Cognitive Deficits ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neuronal Response ◽  
Neutrophil Infiltration ◽  
Biologically Active ◽  
Venous Injury

Background and Purpose: Aneurysmal subarachnoid hemorrhage (SAH) is associated with the development of delayed cognitive deficits. Neutrophil infiltration into the central nervous system is linked to the development of these deficits after SAH. It is however unclear how neutrophil activity influences central nervous system function in SAH. The present project aims to elucidate which neutrophil factors mediate central nervous system injury and cognitive deficits after SAH. Methods: Using a murine model of SAH and mice deficient in neutrophil effector functions, we determined which neutrophil effector function is critical to the development of deficits after SAH. In vivo and in vitro techniques were used to investigate possible pathways of neutrophils effect after SAH. Results: Our results show that mice lacking functional MPO (myeloperoxidase), a neutrophil enzyme, lack both the meningeal neutrophil infiltration (wild type, sham 872 cells/meninges versus SAH 3047, P =0.023; myeloperoxidase knockout [MPOKO], sham 1677 versus SAH 1636, P =NS) and erase the cognitive deficits on Barnes maze associated with SAH (MPOKO sham versus SAH, P =NS). The reintroduction of biologically active MPO, and its substrate hydrogen peroxide (H 2 O 2 ), to the cerebrospinal fluid of MPOKO mice at the time of hemorrhage restores the spatial memory deficit observed after SAH (time to goal box MPOKO sham versus MPOKO+MPO/H 2 O 2 , P =0.001). We find evidence of changes in neurons, astrocytes, and microglia with MPO/H 2 O 2 suggesting the effect of MPO may have complex interactions with many cell types. Neurons exposed to MPO/H 2 O 2 show decreased calcium activity at baseline and after stimulation with potassium chloride. Although astrocytes and microglia are affected, changes seen in astrocytes are most consistent with inflammatory changes that likely affect neurons. Conclusions: These results implicate MPO as a mediator of neuronal dysfunction in SAH through its effect on both neurons and glia. These results show that, in SAH, the activity of innate immune cells in the meninges modulates the activity and function of the underlying brain tissue.

scholarly journals Microglial Function and Regulation during Development, Homeostasis and Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 957
Author(s):  
Brad T. Casali ◽  
Erin G. Reed-Geaghan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Immune Cells ◽  
Expression Patterns ◽  
Brain Parenchyma ◽  
Primary Role ◽  
And Function ◽  
Inflammatory Milieu ◽  
The Brain ◽  
Homeostatic State

Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer’s disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.

scholarly journals 60 YEARS OF POMC: Lipotropin and beta-endorphin: a perspective

2016 ◽  
Vol 56 (4) ◽  
pp. T13-T25 ◽  
Author(s):  
D G Smyth
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Structure And Function ◽  
Biologically Active ◽  
Molecular Endocrinology ◽  
And Function ◽  
The Brain ◽  
Quantitative Amino Acid Analysis

Many important fields of research had a humble origin. In the distant past, A J P Martin’s discovery that amino acids could be separated by paper chromatography and Moore and Stein’s use of columns for quantitative amino acid analysis provided the first steps towards the determination of structure in complex biologically active molecules. They opened the door to reveal the essential relationship that exists between structure and function. In molecular endocrinology, for example, striking advances have been made by chemists with their expertise in the identification of structure working with biologists who contributed valuable knowledge and experience. Advantage was gained from the convergence of different background, and it is notable that the whole is greater than the sum. In the determination of structure, it may be recalled that four of the world’s great pioneers (Archibald Martin, Rodney Porter, Fred Sanger and Vincent du Vigneaud) were acknowledged for their fundamental contributions when individually they were awarded the Nobel Prize. They foresaw that the identification of structure would prove of outstanding importance in the future. Indeed, study of the structures of β-endorphin and enkephalin and the different forms of opiate activity they engender has led to a transformation in our understanding of chemical transmission in the brain.

RELATIONSHIP OF THE MET ALLELE OF THE BRAIN-DERIVED NEUROTROPHIC FACTOR VAL66MET POLYMORPHISM TO MEMORY AFTER ANEURYSMAL SUBARACHNOID HEMORRHAGE

Neurosurgery ◽  
2008 ◽  
Vol 63 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Juhani Vilkki ◽  
Jaakko Lappalainen ◽  
Seppo Juvela ◽  
Katarzyna Kanarek ◽  
Juha A. Hernesniemi ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Neurotrophic Factor ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Brain Derived Neurotrophic Factor ◽  
Val66met Polymorphism ◽  
Relationship Of ◽  
The Brain

scholarly journals Nanoparticle brain delivery: a guide to verification methods

Nanomedicine ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 409-432 ◽  
Author(s):  
Robert A Yokel
Keyword(s):  
Cerebrospinal Fluid ◽  
Extracellular Space ◽  
Brain Parenchyma ◽  
Brain Delivery ◽  
Peripheral Organ ◽  
Blood Brain ◽  
Verification Methods ◽  
Brain Parenchymal ◽  
And Function ◽  
The Brain

Many reports conclude nanoparticle (NP) brain entry based on bulk brain analysis. Bulk brain includes blood, cerebrospinal fluid and blood vessels within the brain contributing to the blood–brain and blood–cerebrospinal fluid barriers. Considering the brain as neurons, glia and their extracellular space (brain parenchyma), most studies did not show brain parenchymal NP entry. Blood–brain and blood–cerebrospinal fluid barriers anatomy and function are reviewed. Methods demonstrating brain parenchymal NP entry are presented. Results demonstrating bulk brain versus brain parenchymal entry are classified. Studies are reviewed, critiqued and classified to illustrate results demonstrating bulk brain versus parenchymal entry. Brain, blood and peripheral organ NP timecourses are compared and related to brain parenchymal entry evidence suggesting brain NP timecourse informs about brain parenchymal entry.

Abstract 192: Mechano-growth Factor (MGF) and Cerebral Vasospasm (CV) Post Aneurysmal Subarachnoid Hemorrhage (aSAH)

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Magdalena M Przybycien-Szymanska ◽  
Todd M Rackohn ◽  
Yuchen Yang ◽  
William W Ashley
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Growth Factor ◽  
Cerebral Vasospasm ◽  
Molecular Mechanisms ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Ischemic Injury ◽  
Brain Regions ◽  
Heme Oxygenase 1 ◽  
Mechano Growth Factor ◽  
The Brain

Cerebral vasospasm (CV) and related ischemic injury is a major contributor to death and disability after aneurysmal subarachnoid hemorrhage (aSAH). Our overall goal is to understand molecular mechanisms of action of endogenous mechano-growth factor (MGF), a splice variant of insulin-like growth factor 1 (IGF-1), in the brain. MGF was found to be neuroprotective after stroke in a gerbil model of ischemic injury and may serve as a potential therapeutic target to prevent CV-induced brain damage. In our studies, we characterized hypoxia induced changes in MGF expression in different brain regions, commonly affected by CV, at different time points (from 2 hours to 7 days) post 4h hypoxia treatments (6, 8,10 or 12% oxygen). The brain regions analyzed were motor cortex, hippocampus, striatum and hypothalamus. In addition, we characterized changes in MGF expression in microparticle (MP) fractions isolated from cerebrospinal fluid (CSF) extracted from CV patients. Microparticle fractions were isolated from CSF samples using serial ultracentrifugation. We used real time RT-PCR, western blots, and enzyme immunosorbent assay to quantify changes in gene expression and protein levels. In the animal model, our results showed that there were time, dose and brain region specific changes in MGF expression that correlated with changes in the expression of heme oxygenase 1 (HO-1) and biliverdin reductase A, which are molecules involved in neuroprotection, and caspases, apoptotic markers. These results suggest that changes in endogenous MGF due to hypoxia may activate neuroprotective pathways in the brain. In CSF MPs isolated from CV patients, we observed an increase in MGF expression that correlated with the CV onset window and with an increase in HO-1, suggesting that similar pathways are activated post-CV in humans and post-hypoxia in animals. These data indicate that endogenous MGF may play a role in CV onset and may be a neuroprotective target in CV papteins. However, further studies are required to elucidate the molecular mechanisms of MGF and its exact role in CV development and patient outcome.

scholarly journals Clinical characteristics and outcome of aneurysmal subarachnoid hemorrhage with intracerebral hematoma

2016 ◽  
Vol 125 (6) ◽  
pp. 1344-1351 ◽  
Author(s):  
Anthony Wan ◽  
Blessing N. R. Jaja ◽  
Tom A. Schweizer ◽  
R. Loch Macdonald
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Early Treatment ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neurological Status ◽  
Aneurysm Rupture ◽  
Study Data ◽  
Intracerebral Hematoma ◽  
Pia Mater ◽  
Proportional Odds Models ◽  
The Brain

OBJECTIVE Intracerebral hematoma (ICH) with subarachnoid hemorrhage (SAH) indicates a unique feature of intracranial aneurysm rupture since the aneurysm is in the subarachnoid space and separated from the brain by pia mater. Broad consensus is lacking regarding the concept that ultra-early treatment improves outcome. The aim of this study is to determine the associative factors for ICH, ascertain the prognostic value of ICH, and investigate how the timing of treatment relates to the outcome of SAH with concurrent ICH. METHODS The study data were pooled from the SAH International Trialists repository. Logistic regression was applied to study the associations of clinical and aneurysm characteristics with ICH. Proportional odds models and dominance analysis were applied to study the effect of ICH on 3-month outcome (Glasgow Outcome Scale) and investigate the effect of time from ictus to treatment on outcome. RESULTS Of the 5362 SAH patients analyzed, 1120 (21%) had concurrent ICH. In order of importance, neurological status, aneurysm location, aneurysm size, and patient ethnicity were significantly associated with ICH. Patients with ICH experienced poorer outcome than those without ICH (OR 1.58; 95% CI 1.37–1.82). Treatment within 6 hours of SAH was associated with poorer outcome than treatment thereafter (adjusted OR 1.67; 95% CI 1.04–2.69). Subgroup analysis with adjustment for ICH volume, location, and midline shift resulted in no association between time from ictus to treatment and outcome (OR 0.99; 95% CI 0.94–1.07). CONCLUSIONS The most important associative factor for ICH is neurological status on admission. The finding regarding the value of ultra-early treatment suggests the need to more robustly reevaluate the concept that hematoma evacuation of an ICH and repair of a ruptured aneurysm within 6 hours of ictus is the most optimal treatment path.

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