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Palakshappa JA, Batt JAE, Bodine SC, Connolly BA, Doles J, Falvey JR, Ferrante LE, Files DC, Harhay MO, Harrell K, Hippensteel JA, Iwashyna TJ, Jackson JC, Lane-Fall MB, Monje M, Moss M, Needham DM, Semler MW, Lahiri S, Larsson L, Sevin CM, Sharshar T, Singer B, Stevens T, Taylor SP, Gomez CR, Zhou G, Girard TD, Hough CL. Tackling Brain and Muscle Dysfunction in Acute Respiratory Distress Syndrome Survivors: NHLBI Workshop Report. Am J Respir Crit Care Med 2024; 209:1304-1313. [PMID: 38477657 PMCID: PMC11146564 DOI: 10.1164/rccm.202311-2130ws] [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: 11/20/2023] [Accepted: 03/12/2024] [Indexed: 03/14/2024] Open
Abstract
Acute respiratory distress syndrome (ARDS) is associated with long-term impairments in brain and muscle function that significantly impact the quality of life of those who survive the acute illness. The mechanisms underlying these impairments are not yet well understood, and evidence-based interventions to minimize the burden on patients remain unproved. The NHLBI of the NIH assembled a workshop in April 2023 to review the state of the science regarding ARDS-associated brain and muscle dysfunction, to identify gaps in current knowledge, and to determine priorities for future investigation. The workshop included presentations by scientific leaders across the translational science spectrum and was open to the public as well as the scientific community. This report describes the themes discussed at the workshop as well as recommendations to advance the field toward the goal of improving the health and well-being of ARDS survivors.
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Affiliation(s)
| | - Jane A. E. Batt
- University of Toronto Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Sue C. Bodine
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, Oklahoma
| | - Bronwen A. Connolly
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University, Belfast, United Kingdom
| | - Jason Doles
- Indiana University School of Medicine, Indianapolis, Indiana
| | - Jason R. Falvey
- University of Maryland School of Medicine, Baltimore, Maryland
| | | | - D. Clark Files
- Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Michael O. Harhay
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | | | | | | | | | - Meghan B. Lane-Fall
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Michelle Monje
- Howard Hughes Medical Institute, Stanford University, Stanford, California
| | - Marc Moss
- University of Colorado School of Medicine, Aurora, Colorado
| | - Dale M. Needham
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Shouri Lahiri
- Cedars Sinai Medical Center, Los Angeles, California
| | - Lars Larsson
- Center for Molecular Medicine, Karolinska Institute, Solna, Sweden
- Department of Physiology & Pharmacology, Karolinska Institute and Viron Molecular Medicine Institute, Boston, Massachusetts
| | - Carla M. Sevin
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Tarek Sharshar
- Anesthesia and Intensive Care Department, GHU Paris Psychiatry and Neurosciences, Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, University Paris Cité, Paris, France
| | | | | | | | - Christian R. Gomez
- Division of Lung Diseases, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Guofei Zhou
- Division of Lung Diseases, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Timothy D. Girard
- Center for Research, Investigation, and Systems Modeling of Acute Illness, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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2
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Fischer I, Connors T, Bouyer J, Jin Y. The unique properties of Big tau in the visual system. Cytoskeleton (Hoboken) 2024. [PMID: 38761116 DOI: 10.1002/cm.21875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/29/2024] [Accepted: 04/26/2024] [Indexed: 05/20/2024]
Abstract
Tau is a microtubule associated protein that plays important roles in regulating the properties of microtubules and axonal transport, as well as tauopathies associated with toxic aggregates leading to neurodegenerative diseases. It is encoded by the MAPT gene forming multiple isoforms (45-60 kDa) by alternative splicing which are developmentally regulated. The high molecular weight (MW) tau isoform of 105 kDa, termed Big tau, was originally discovered in the peripheral nervous system (PNS) but later found in selective CNS areas. It contains an additional large exon 4a generating a long projecting domain of about 250 amino acids. Here we investigated the properties of Big tau in the visual system of rats, its distribution in retinal ganglion cells and the optic nerve as well as its developmental regulation using biochemical, molecular and histological analyses. We discovered that Big tau is expresses as a 95 kDa protein (termed middle MW) containing exons 4a, 6 as well as exon 10 which defines a 4 microtubule-binding repeats (4R). It lacks exons 2/3 but shares the extensive phosphorylation characteristic of other tau isoforms. Importantly, early in development the visual system expresses only the low MW isoform (3R) switching to both the low and middle MW isoforms (4R) in adult retinal ganglion neurons and their corresponding axons. This is a unique structure and expression pattern of Big tau, which we hypothesize is associated with the specific properties of the visual system different from what has been previously described in the PNS and other areas of the nervous system.
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Affiliation(s)
- Itzhak Fischer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Theresa Connors
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Julien Bouyer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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3
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Mughal A, Sackheim AM, Koide M, Bonson G, Ebner G, Hennig G, Lockette W, Nelson MT, Freeman K. Pathogenic soluble tau peptide disrupts endothelial calcium signaling and vasodilation in the brain microvasculature. J Cereb Blood Flow Metab 2024; 44:680-688. [PMID: 38420777 PMCID: PMC11197144 DOI: 10.1177/0271678x241235790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/03/2024] [Accepted: 01/27/2024] [Indexed: 03/02/2024]
Abstract
The accumulation of the microtubule-associated tau protein in and around blood vessels contributes to brain microvascular dysfunction through mechanisms that are incompletely understood. Delivery of nutrients to active neurons in the brain relies on capillary calcium (Ca2+) signals to direct blood flow. The initiation and amplification of endothelial cell Ca2+ signals require an intact microtubule cytoskeleton. Since tau accumulation in endothelial cells disrupts native microtubule stability, we reasoned that tau-induced microtubule destabilization would impair endothelial Ca2+ signaling. We tested the hypothesis that tau disrupts the regulation of local cerebral blood flow by reducing endothelial cell Ca2+ signals and endothelial-dependent vasodilation. We used a pathogenic soluble tau peptide (T-peptide) model of tau aggregation and mice with genetically encoded endothelial Ca2+ sensors to measure cerebrovascular endothelial responses to tau exposure. T-peptide significantly attenuated endothelial Ca2+ activity and cortical capillary blood flow in vivo. Further, T-peptide application constricted pressurized cerebral arteries and inhibited endothelium-dependent vasodilation. This study demonstrates that pathogenic tau alters cerebrovascular function through direct attenuation of endothelial Ca2+ signaling and endothelium-dependent vasodilation.
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Affiliation(s)
- Amreen Mughal
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Adrian M Sackheim
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
| | - Masayo Koide
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Grace Bonson
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
| | - Grace Ebner
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Grant Hennig
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Warren Lockette
- Division of Endocrinology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Mark T Nelson
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Kalev Freeman
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
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4
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Balczon R, Lin MT, Voth S, Nelson AR, Schupp JC, Wagener BM, Pittet JF, Stevens T. Lung endothelium, tau, and amyloids in health and disease. Physiol Rev 2024; 104:533-587. [PMID: 37561137 PMCID: PMC11281824 DOI: 10.1152/physrev.00006.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/26/2023] [Accepted: 08/04/2023] [Indexed: 08/11/2023] Open
Abstract
Lung endothelia in the arteries, capillaries, and veins are heterogeneous in structure and function. Lung capillaries in particular represent a unique vascular niche, with a thin yet highly restrictive alveolar-capillary barrier that optimizes gas exchange. Capillary endothelium surveys the blood while simultaneously interpreting cues initiated within the alveolus and communicated via immediately adjacent type I and type II epithelial cells, fibroblasts, and pericytes. This cell-cell communication is necessary to coordinate the immune response to lower respiratory tract infection. Recent discoveries identify an important role for the microtubule-associated protein tau that is expressed in lung capillary endothelia in the host-pathogen interaction. This endothelial tau stabilizes microtubules necessary for barrier integrity, yet infection drives production of cytotoxic tau variants that are released into the airways and circulation, where they contribute to end-organ dysfunction. Similarly, beta-amyloid is produced during infection. Beta-amyloid has antimicrobial activity, but during infection it can acquire cytotoxic activity that is deleterious to the host. The production and function of these cytotoxic tau and amyloid variants are the subject of this review. Lung-derived cytotoxic tau and amyloid variants are a recently discovered mechanism of end-organ dysfunction, including neurocognitive dysfunction, during and in the aftermath of infection.
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Affiliation(s)
- Ron Balczon
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mike T Lin
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Sarah Voth
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Monroe, Louisiana, United States
| | - Amy R Nelson
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jonas C Schupp
- Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yale University, New Haven, Connecticut, United States
- Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany
- German Center for Lung Research (DZL), Hannover, Germany
| | - Brant M Wagener
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Troy Stevens
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Department of Internal Medicine, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
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Yu PC, Kuo CM, Chen IC. Tau and delirium superimposed on dementia: A case report. SAGE Open Med Case Rep 2024; 12:2050313X241243148. [PMID: 38559407 PMCID: PMC10981243 DOI: 10.1177/2050313x241243148] [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: 10/13/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
We present a case involving a 60-year-old man with subacute delirium characterized by challenging attention shifts and obstinate behavior, contrasting with his usual mild-mannered personality. The patient developed pneumonia and a urinary tract infection following the onset of subacute delirium. Despite exhaustive investigations, the cause remained elusive until cerebrospinal fluid analysis revealed Tau positivity. Our overview suggests neurodegenerative diseases as the primary cause, rather than infectious or autoimmune factors. The case underscores a significant association between Tau and delirium superimposed on dementia, offering guidance to clinicians managing such patients.
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Affiliation(s)
- Po-Chung Yu
- Department of Psychiatry, Taichung Veterans General Hospital, Taichung City, Taiwan
| | - Ching-Min Kuo
- Department of Psychiatry, Taichung Veterans General Hospital, Taichung City, Taiwan
| | - I-Chun Chen
- Department of Psychiatry, Taichung Veterans General Hospital, Taichung City, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung City, Taiwan
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6
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Fischer I. Big tau: What, how, where and why. Cytoskeleton (Hoboken) 2024; 81:10-15. [PMID: 37578198 DOI: 10.1002/cm.21772] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/15/2023]
Abstract
Over the last 50 years the different isoforms of tau proteins (45-60 kDa) have been a focus of research because of their roles in modulating the dynamic properties of microtubules shaping the structure and function of neurons but also becoming a center of attention in the pathology of neurodegeneration associated with tauopathies. Much less attention has been given to Big tau, a unique isoform containing exon 4a encoding about 250 amino acids to form a much longer projection domain of a protein of 110 kDa. Big tau is expressed in peripheral neurons and selective regions of the central nervous system in a defined transition during postnatal developmental stages. Although Big tau was discovered 30 years ago, there has been a persistent gap of knowledge regarding its physiological properties and pathological implications. This Perspective summarizes the progress so far in defining the structure and expression of Big tau within and outside the nervous system, proposes a role for Big tau in improving axonal transport in projecting axons, considers its potential in averting tau aggregation in tauopathies and highlights the need for further progress.
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Affiliation(s)
- Itzhak Fischer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Qian X, Hai W, Chen S, Zhang M, Jiang X, Tang H. Multi-omics data reveals aberrant gut microbiota-host glycerophospholipid metabolism in association with neuroinflammation in APP/PS1 mice. Gut Microbes 2023; 15:2282790. [PMID: 37992400 PMCID: PMC10730179 DOI: 10.1080/19490976.2023.2282790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023] Open
Abstract
Numerous studies have described the notable impact of gut microbiota on the brain in Alzheimer's disease (AD) via the gut - brain axis. However, the molecular mechanisms underlying the involvement of gut microbiota in the development of AD are limited. This study aimed to explore the potential mechanisms of gut microbiota in AD by integrating multi-omics data. In this study, APP/PS1 and WT mice at nine months of age were used as study mouse model. Cognitive function was assessed using the Morris water maze test. The levels of Aβ plaque and neuroinflammation in the brain were detected using immunofluorescence and PET/CT. In addition, we not only used 16S rRNA gene sequencing and metabolomics to explore the variation characteristics of gut microbiota and serum metabolism abundance, but also combined spatial metabolomics and transcriptomics to explore the change in the brain and identify their potential correlation. APP/PS1 mice showed significant cognitive impairment and amyloid-β deposits in the brain. The abundance of gut microbiota was significantly changed in APP/PS1 mice, including decreased Desulfoviobrio, Enterococcus, Turicibacter, and Ruminococcus and increased Pseudomonas. The integration of serum untargeted metabolomics and brain spatial metabolomics showed that glycerophospholipid metabolism was a common alteration pathway in APP/PS1 mice. Significant proliferation and activation of astrocyte and microglia were observed in APP/PS1 mice, accompanied by alterations in immune pathways. Integration analysis and fecal microbiota transplantation (FMT) intervention revealed potential association of gut microbiota, host glycerophospholipid metabolism, and neuroinflammation levels in APP/PS1 mice.
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Affiliation(s)
- Xiaohang Qian
- Department of Geriatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Medical Center on Aging of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wangxi Hai
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Siyue Chen
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Miao Zhang
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xufeng Jiang
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huidong Tang
- Department of Geriatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Medical Center on Aging of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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8
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Walker A, Czyz DM. Oh my gut! Is the microbial origin of neurodegenerative diseases real? Infect Immun 2023; 91:e0043722. [PMID: 37750713 PMCID: PMC10580905 DOI: 10.1128/iai.00437-22] [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] [Indexed: 09/27/2023] Open
Abstract
There is no cure or effective treatment for neurodegenerative protein conformational diseases (PCDs), such as Alzheimer's or Parkinson's diseases, mainly because the etiology of these diseases remains elusive. Recent data suggest that unique changes in the gut microbial composition are associated with these ailments; however, our current understanding of the bacterial role in the pathogenesis of PCDs is hindered by the complexity of the microbial communities associated with specific microbiomes, such as the gut, oral, or vaginal microbiota. The composition of these specific microbiomes is regarded as a unique fingerprint affected by factors such as infections, diet, lifestyle, and antibiotics. All of these factors also affect the severity of neurodegenerative diseases. The majority of studies that reveal microbial contribution are correlational, and various models, including worm, fly, and mouse, are being utilized to decipher the role of individual microbes that may affect disease onset and progression. Recent evidence from across model organisms and humans shows a positive correlation between the presence of gram-negative enteropathogenic bacteria and the pathogenesis of PCDs. While these correlational studies do not provide a mechanistic explanation, they do reveal contributing bacterial species and provide an important basis for further investigation. One of the lurking concerns related to the microbial contribution to PCDs is the increasing prevalence of antibiotic resistance and poor antibiotic stewardship, which ultimately select for proteotoxic bacteria, especially the gram-negative species that are known for intrinsic resistance. In this review, we summarize what is known about individual microbial contribution to PCDs and the potential impact of increasing antimicrobial resistance.
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Affiliation(s)
- Alyssa Walker
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Daniel M. Czyz
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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9
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Freeman K, Sackheim AM, Mughal A, Koide M, Bonson G, Ebner G, Hennig G, Lockette W, Nelson MT. Pathogenic soluble tau peptide disrupts endothelial calcium signaling and vasodilation in the brain microvasculature. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552492. [PMID: 37609200 PMCID: PMC10441279 DOI: 10.1101/2023.08.08.552492] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The accumulation of the microtubule-associated tau protein in and around blood vessels contributes to brain microvascular dysfunction through mechanisms that are incompletely understood. Delivery of nutrients to active neurons in the brain relies on capillary inositol 1,4,5-triphosphate receptor (IP3R)-mediated calcium (Ca2+) signals to direct blood flow. The initiation and amplification of endothelial cell IP3R-mediated Ca2+ signals requires an intact microtubule cytoskeleton. Since tau accumulation in endothelial cells disrupts native microtubule stability, we reasoned that tau-induced microtubule destabilization would impair endothelial IP3-evoked Ca2+ signaling. We tested the hypothesis that tau disrupts the regulation of local cerebral blood flow by reducing endothelial cell Ca2+ signals and endothelial-dependent vasodilation. We used a pathogenic soluble tau peptide (T-peptide) model of tau aggregation and mice with genetically encoded endothelial Ca2+ sensors to measure cerebrovascular endothelial responses to tau exposure. T-peptide significantly attenuated endothelial Ca2+ activity and cortical capillary blood flow in vivo within 120 seconds. Further, T-peptide application constricted pressurized cerebral arteries and inhibited endothelium-dependent vasodilation. This study demonstrates that pathogenic tau alters cerebrovascular function through direct attenuation of endothelial Ca2+ signaling and endothelium-dependent vasodilation.
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Affiliation(s)
- Kalev Freeman
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Adrian M Sackheim
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
| | - Amreen Mughal
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Masayo Koide
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Grace Bonson
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
| | - Grace Ebner
- Department of Emergency Medicine, University of Vermont, Burlington, VT, USA
| | - Grant Hennig
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Warren Lockette
- Division of Endocrinology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Mark T Nelson
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
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10
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Gwin MS, Alexeyev MF, Geurts AM, Lee JY, Zhou C, Yang XM, Cohen MV, Downey JM, Barrington RA, Spadafora D, Audia JP, Frank DW, Voth S, Pastukh VV, Bell J, Ayers L, Tambe DT, Nelson AR, Balczon R, Lin MT, Stevens T. Gamma secretase activating protein promotes end-organ dysfunction after bacterial pneumonia. Am J Physiol Lung Cell Mol Physiol 2023; 325:L174-L189. [PMID: 37366533 PMCID: PMC10396227 DOI: 10.1152/ajplung.00018.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023] Open
Abstract
Pneumonia elicits the production of cytotoxic beta amyloid (Aβ) that contributes to end-organ dysfunction, yet the mechanism(s) linking infection to activation of the amyloidogenic pathway that produces cytotoxic Aβ is unknown. Here, we tested the hypothesis that gamma-secretase activating protein (GSAP), which contributes to the amyloidogenic pathway in the brain, promotes end-organ dysfunction following bacterial pneumonia. First-in-kind Gsap knockout rats were generated. Wild-type and knockout rats possessed similar body weights, organ weights, circulating blood cell counts, arterial blood gases, and cardiac indices at baseline. Intratracheal Pseudomonas aeruginosa infection caused acute lung injury and a hyperdynamic circulatory state. Whereas infection led to arterial hypoxemia in wild-type rats, the alveolar-capillary barrier integrity was preserved in Gsap knockout rats. Infection potentiated myocardial infarction following ischemia-reperfusion injury, and this potentiation was abolished in knockout rats. In the hippocampus, GSAP contributed to both pre- and postsynaptic neurotransmission, increasing the presynaptic action potential recruitment, decreasing neurotransmitter release probability, decreasing the postsynaptic response, and preventing postsynaptic hyperexcitability, resulting in greater early long-term potentiation but reduced late long-term potentiation. Infection abolished early and late long-term potentiation in wild-type rats, whereas the late long-term potentiation was partially preserved in Gsap knockout rats. Furthermore, hippocampi from knockout rats, and both the wild-type and knockout rats following infection, exhibited a GSAP-dependent increase in neurotransmitter release probability and postsynaptic hyperexcitability. These results elucidate an unappreciated role for GSAP in innate immunity and highlight the contribution of GSAP to end-organ dysfunction during infection.NEW & NOTEWORTHY Pneumonia is a common cause of end-organ dysfunction, both during and in the aftermath of infection. In particular, pneumonia is a common cause of lung injury, increased risk of myocardial infarction, and neurocognitive dysfunction, although the mechanisms responsible for such increased risk are unknown. Here, we reveal that gamma-secretase activating protein, which contributes to the amyloidogenic pathway, is important for end-organ dysfunction following infection.
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Affiliation(s)
- Meredith S Gwin
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Ji Young Lee
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Chun Zhou
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Xi-Ming Yang
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Michael V Cohen
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - James M Downey
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Robert A Barrington
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Domenico Spadafora
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jonathon P Audia
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Dara W Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Sarah Voth
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Monroe, Louisiana, United States
| | - Viktoriya V Pastukh
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jessica Bell
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Linn Ayers
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Dhananjay T Tambe
- Department of Mechanical, Aerospace, and Biomedical Engineering, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Amy R Nelson
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Ron Balczon
- Department of Biochemistry and Molecular Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mike T Lin
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Troy Stevens
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
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11
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Balczon R, Choi CS, deWeever A, Zhou C, Gwin MS, Kolb C, Francis CM, Lin MT, Stevens T. Infection promotes Ser-214 phosphorylation important for generation of cytotoxic tau variants. FASEB J 2023; 37:e23042. [PMID: 37358817 DOI: 10.1096/fj.202300620rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 06/27/2023]
Abstract
Patients who recover from hospital-acquired pneumonia exhibit a high incidence of end-organ dysfunction following hospital discharge, including cognitive deficits. We have previously demonstrated that pneumonia induces the production and release of cytotoxic oligomeric tau from pulmonary endothelial cells, and these tau oligomers can enter the circulation and may be a cause of long-term morbidities. Endothelial-derived oligomeric tau is hyperphosphorylated during infection. The purpose of these studies was to determine whether Ser-214 phosphorylation of tau is a necessary stimulus for generation of cytotoxic tau variants. The results of these studies demonstrate that Ser-214 phosphorylation is critical for the cytotoxic properties of infection-induced oligomeric tau. In the lung, Ser-214 phosphorylated tau contributes to disruption of the alveolar-capillary barrier, resulting in increased permeability. However, in the brain, both the Ser-214 phosphorylated tau and the mutant Ser-214-Ala tau, which cannot be phosphorylated, disrupted hippocampal long-term potentiation suggesting that inhibition of long-term potentiation was relatively insensitive to the phosphorylation status of Ser-214. Nonetheless, phosphorylation of tau is essential to its cytotoxicity since global dephosphorylation of the infection-induced cytotoxic tau variants rescued long-term potentiation. Collectively, these data demonstrate that multiple forms of oligomeric tau are generated during infectious pneumonia, with different forms of oligomeric tau being responsible for dysfunction of distinct end-organs during pneumonia.
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Affiliation(s)
- Ron Balczon
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Chung-Sik Choi
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Althea deWeever
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Chun Zhou
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Meredith S Gwin
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Claire Kolb
- Department of Biochemistry and Molecular Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - C Michael Francis
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Mike T Lin
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Troy Stevens
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
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12
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Johnson AM, Lukens JR. The innate immune response in tauopathies. Eur J Immunol 2023; 53:e2250266. [PMID: 36932726 PMCID: PMC10247424 DOI: 10.1002/eji.202250266] [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: 01/06/2023] [Revised: 02/23/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023]
Abstract
Tauopathies, which include frontotemporal dementia, Alzheimer's disease, and chronic traumatic encephalopathy, are a class of neurological disorders resulting from pathogenic tau aggregates. These aggregates disrupt neuronal health and function leading to the cognitive and physical decline of tauopathy patients. Genome-wide association studies and clinical evidence have brought to light the large role of the immune system in inducing and driving tau-mediated pathology. More specifically, innate immune genes are found to harbor tauopathy risk alleles, and innate immune pathways are upregulated throughout the course of disease. Experimental evidence has expanded on these findings by describing pivotal roles for the innate immune system in the regulation of tau kinases and tau aggregates. In this review, we summarize the literature implicating innate immune pathways as drivers of tauopathy.
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Affiliation(s)
- Alexis M. Johnson
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- BIG Training Graduate Program, UVA, Charlottesville, VA 22908, USA
| | - John R. Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia (UVA), Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, UVA, Charlottesville, VA 22908, USA
- BIG Training Graduate Program, UVA, Charlottesville, VA 22908, USA
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13
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Tiedt S, Buchan AM, Dichgans M, Lizasoain I, Moro MA, Lo EH. The neurovascular unit and systemic biology in stroke - implications for translation and treatment. Nat Rev Neurol 2022; 18:597-612. [PMID: 36085420 DOI: 10.1038/s41582-022-00703-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2022] [Indexed: 12/24/2022]
Abstract
Ischaemic stroke is a leading cause of disability and death for which no acute treatments exist beyond recanalization. The development of novel therapies has been repeatedly hindered by translational failures that have changed the way we think about tissue damage after stroke. What was initially a neuron-centric view has been replaced with the concept of the neurovascular unit (NVU), which encompasses neuronal, glial and vascular compartments, and the biphasic nature of neural-glial-vascular signalling. However, it is now clear that the brain is not the private niche it was traditionally thought to be and that the NVU interacts bidirectionally with systemic biology, such as systemic metabolism, the peripheral immune system and the gut microbiota. Furthermore, these interactions are profoundly modified by internal and external factors, such as ageing, temperature and day-night cycles. In this Review, we propose an extension of the concept of the NVU to include its dynamic interactions with systemic biology. We anticipate that this integrated view will lead to the identification of novel mechanisms of stroke pathophysiology, potentially explain previous translational failures, and improve stroke care by identifying new biomarkers of and treatment targets in stroke.
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Affiliation(s)
- Steffen Tiedt
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA), . .,Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Alastair M Buchan
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA).,Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Martin Dichgans
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA).,Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Ignacio Lizasoain
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA).,Department of Pharmacology and Toxicology, Complutense Medical School, Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain
| | - Maria A Moro
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA).,Centro Nacional de Investigaciones Cardiovasculares, CNIC, Madrid, Spain
| | - Eng H Lo
- Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA), . .,Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. .,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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14
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Saiyasit N, Butlig EAR, Chaney SD, Traylor MK, Hawley NA, Randall RB, Bobinger HV, Frizell CA, Trimm F, Crook ED, Lin M, Hill BD, Keller JL, Nelson AR. Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease. Front Neurosci 2022; 16:915405. [PMID: 35844216 PMCID: PMC9279126 DOI: 10.3389/fnins.2022.915405] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/31/2022] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.
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Affiliation(s)
- Napatsorn Saiyasit
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Evan-Angelo R. Butlig
- Department of Neurology, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Intellectual and Developmental Disabilities Research Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - Samantha D. Chaney
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Miranda K. Traylor
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Nanako A. Hawley
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Ryleigh B. Randall
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Hanna V. Bobinger
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Carl A. Frizell
- Department of Physician Assistant Studies, University of South Alabama, Mobile, AL, United States
| | - Franklin Trimm
- College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Errol D. Crook
- Department of Internal Medicine, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Mike Lin
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Benjamin D. Hill
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Joshua L. Keller
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Amy R. Nelson
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
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15
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Nelson AR. Peripheral Pathways to Neurovascular Unit Dysfunction, Cognitive Impairment, and Alzheimer’s Disease. Front Aging Neurosci 2022; 14:858429. [PMID: 35517047 PMCID: PMC9062225 DOI: 10.3389/fnagi.2022.858429] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/03/2022] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. It was first described more than a century ago, and scientists are acquiring new data and learning novel information about the disease every day. Although there are nuances and details continuously being unraveled, many key players were identified in the early 1900’s by Dr. Oskar Fischer and Dr. Alois Alzheimer, including amyloid-beta (Aβ), tau, vascular abnormalities, gliosis, and a possible role of infections. More recently, there has been growing interest in and appreciation for neurovascular unit dysfunction that occurs early in mild cognitive impairment (MCI) before and independent of Aβ and tau brain accumulation. In the last decade, evidence that Aβ and tau oligomers are antimicrobial peptides generated in response to infection has expanded our knowledge and challenged preconceived notions. The concept that pathogenic germs cause infections generating an innate immune response (e.g., Aβ and tau produced by peripheral organs) that is associated with incident dementia is worthwhile considering in the context of sporadic AD with an unknown root cause. Therefore, the peripheral amyloid hypothesis to cognitive impairment and AD is proposed and remains to be vetted by future research. Meanwhile, humans remain complex variable organisms with individual risk factors that define their immune status, neurovascular function, and neuronal plasticity. In this focused review, the idea that infections and organ dysfunction contribute to Alzheimer’s disease, through the generation of peripheral amyloids and/or neurovascular unit dysfunction will be explored and discussed. Ultimately, many questions remain to be answered and critical areas of future exploration are highlighted.
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