1
|
Tariq M, Liu Y, Rizwan A, Shoukat CA, Aftab Q, Lu J, Zhang Y. Impact of elevated CO 2 on soil microbiota: A meta-analytical review of carbon and nitrogen metabolism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175354. [PMID: 39117202 DOI: 10.1016/j.scitotenv.2024.175354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 07/17/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
In the face of 21st-century challenges driven by population growth and resource depletion, understanding the intricacies of climate change is crucial for environmental sustainability. This review systematically explores the interaction between rising atmospheric CO2 concentrations and soil microbial populations, with possible feedback effects on climate change and terrestrial carbon (C) cycling through a meta-analytical approach. Furthermore, it investigates the enzymatic activities related to carbon acquisition, gene expression patterns governing carbon and nitrogen metabolism, and metagenomic and meta-transcriptomic dynamics in response to elevated CO2 levels. The study reveals that elevated CO2 levels substantially influence soil microbial communities, increasing microbial biomass C and respiration rate by 15 % and upregulating genes involved in carbon and nitrogen metabolism by 12 %. Despite a 14 % increase in C-acquiring enzyme activity, there is a 5 % decrease in N-acquiring enzyme activity, indicating complex microbial responses to CO2 changes. Additionally, fungal marker ratios increase by 14 % compared to bacterial markers, indicating potential ecosystem changes. However, the current inadequacy of data on metagenomic and meta-transcriptomic processes underscores the need for further research. Understanding soil microbial feedback mechanisms is crucial for elucidating the role of rising CO2 levels in carbon sequestration and climate regulation. Consequently, future research should prioritize a comprehensive elucidation of soil microbial carbon cycling, greenhouse gas emission dynamics, and their underlying drivers.
Collapse
Affiliation(s)
- Maryam Tariq
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuexian Liu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ali Rizwan
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38000, Punjab, Pakistan
| | - Chaudhary Ammar Shoukat
- Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qudsia Aftab
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinfeng Lu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanxun Zhang
- Beijing Yanshan Earth Critical Zone National Research Station, University of Chinese Academy of Sciences, Beijing 101408
| |
Collapse
|
2
|
Linares E, Severino D, Truzzi DR, Rios N, Radi R, Augusto O. Production of Peroxymonocarbonate by Steady-State Micromolar H 2O 2 and Activated Macrophages in the Presence of CO 2/HCO 3- Evidenced by Boronate Probes. Chem Res Toxicol 2024; 37:1129-1138. [PMID: 38916595 PMCID: PMC11256887 DOI: 10.1021/acs.chemrestox.4c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 06/26/2024]
Abstract
Peroxymonocarbonate (HCO4-/HOOCO2-) is produced by the reversible reaction of CO2/HCO3- with H2O2 (K = 0.33 M-1, pH 7.0). Although produced in low yields at physiological pHs and H2O2 and CO2/HCO3- concentrations, HCO4- oxidizes most nucleophiles with rate constants 10 to 100 times higher than those of H2O2. Boronate probes are known examples because HCO4- reacts with coumarin-7-boronic acid pinacolate ester (CBE) with a rate constant that is approximately 100 times higher than that of H2O2 and the same holds for fluorescein-boronate (Fl-B) as reported here. Therefore, we tested whether boronate probes could provide evidence for HCO4- formation under biologically relevant conditions. Glucose/glucose oxidase/catalase were adjusted to produce low steady-state H2O2 concentrations (2-18 μM) in Pi buffer at pH 7.4 and 37 °C. Then, CBE (100 μM) was added and fluorescence increase was monitored with time. The results showed that each steady-state H2O2 concentration reacted more rapidly (∼30%) in the presence of CO2/HCO3- (25 mM) than in its absence, and the data permitted the calculation of consistent rate constants. Also, RAW 264.7 macrophages were activated with phorbol 12-myristate 13-acetate (PMA) (1 μg/mL) at pH 7.4 and 37 °C to produce a time-dependent H2O2 concentration (8.0 ± 2.5 μM after 60 min). The media contained 0, 21.6, or 42.2 mM HCO3- equilibrated with 0, 5, or 10% CO2, respectively. In the presence of CBE or Fl-B (30 μM), a time-dependent increase in the fluorescence of the bulk solution was observed, which was higher in the presence of CO2/HCO3- in a concentration-dependent manner. The Fl-B samples were also examined by fluorescence microscopy. Our results demonstrated that mammalian cells produce HCO4- and boronate probes can evidence and distinguish it from H2O2 under biologically relevant concentrations of H2O2 and CO2/HCO3-.
Collapse
Affiliation(s)
- Edlaine Linares
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, Sao Paulo 05508-900, Brazil
| | - Divinomar Severino
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, Sao Paulo 05508-900, Brazil
| | - Daniela R. Truzzi
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, Sao Paulo 05508-900, Brazil
| | - Natalia Rios
- Departamento de Bioquímica and Centro de Investigaciones
Biomédicas
(CEINBIO), Facultad de Medicina, Universidad
de la República, Montevideo 11800, Uruguay
| | - Rafael Radi
- Departamento de Bioquímica and Centro de Investigaciones
Biomédicas
(CEINBIO), Facultad de Medicina, Universidad
de la República, Montevideo 11800, Uruguay
| | - Ohara Augusto
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, Sao Paulo 05508-900, Brazil
| |
Collapse
|
3
|
Campaña-Duel E, Ceccato A, Morales-Quinteros L, Camprubí-Rimblas M, Artigas A. Hypercapnia and its relationship with respiratory infections. Expert Rev Respir Med 2024; 18:41-47. [PMID: 38489161 DOI: 10.1080/17476348.2024.2331767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/13/2024] [Indexed: 03/17/2024]
Abstract
INTRODUCTION Hypercapnia is developed in patients with acute and/or chronic respiratory conditions. Clinical data concerning hypercapnia and respiratory infections interaction is limited. AREAS COVERED Currently, the relationship between hypercapnia and respiratory infections remains unclear. In this review, we summarize studies on the effects of hypercapnia on models of pulmonary infections to clarify the role of elevated CO2 in these pulmonary pathologies. Hypercapnia affects different cell types in the alveoli, leading to changes in the immune response. In vitro studies show that hypercapnia downregulates the NF-κβ pathway, reduces inflammation and impairs epithelial wound healing. While in vivo models show a dual role between short- and long-term effects of hypercapnia on lung infection. However, it is still controversial whether the effects observed under hypercapnia are pH dependent or not. EXPERT OPINION The role of hypercapnia is still a controversial debate. Hypercapnia could play a beneficial role in mechanically ventilated models, by lowering the inflammation produced by the stretch condition. But it could be detrimental in infectious scenarios, causing phagocyte dysfunction and lack of infection control. Further data concerning hypercapnia on respiratory infections is needed to elucidate this interaction.
Collapse
Affiliation(s)
- Elena Campaña-Duel
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Adrian Ceccato
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Intensive care unit, Hospital Universitari Sagrat Cor, Grupo Quironsalud, Barcelona, Spain
| | - Luis Morales-Quinteros
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Servei de Medicina Intensiva, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Marta Camprubí-Rimblas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Antonio Artigas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| |
Collapse
|
4
|
Abstract
Background Identifying CO2-binding proteins is vital for our knowledge of CO2-regulated molecular processes. The carbamate post-translational modification is a reversible CO2-mediated adduct that can form on neutral N-terminal α-amino or lysine ε-amino groups. Methods We have developed triethyloxonium ion (TEO) as a chemical proteomics tool to trap the carbamate post-translational modification on protein covalently. We use 13C-NMR and TEO and identify ubiquitin as a plant CO2-binding protein. Results We observe the carbamate post-translational modification on the Arabidopsis thaliana ubiquitin ε-amino groups of lysines 6, 33, and 48. We show that biologically relevant near atmospheric PCO2 levels increase ubiquitin conjugation dependent on lysine 6. We further demonstrate that CO2 increases the ubiquitin E2 ligase (AtUBC5) charging step via the transthioesterification reaction in which Ub is transferred from the E1 ligase active site to the E2 active site. Conclusions and general significance Therefore, plant ubiquitin is a CO2-binding protein, and the carbamate post-translational modification represents a potential mechanism through which plant cells can respond to fluctuating PCO2.
Collapse
Affiliation(s)
- Harry G Gannon
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Martin J Cann
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, South Road, Durham DH1 3LE, UK
| |
Collapse
|
5
|
Radi R. Interplay of carbon dioxide and peroxide metabolism in mammalian cells. J Biol Chem 2022; 298:102358. [PMID: 35961463 PMCID: PMC9485056 DOI: 10.1016/j.jbc.2022.102358] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 10/25/2022] Open
Abstract
The carbon dioxide/bicarbonate (CO2/HCO3-) molecular pair is ubiquitous in mammalian cells and tissues, mainly as a result of oxidative decarboxylation reactions that occur during intermediary metabolism. CO2 is in rapid equilibrium with HCO3-via the hydration reaction catalyzed by carbonic anhydrases. Far from being an inert compound in redox biology, CO2 enhances or redirects the reactivity of peroxides, modulating the velocity, extent, and type of one- and two-electron oxidation reactions mediated by hydrogen peroxide (H2O2) and peroxynitrite (ONOO-/ONOOH). Herein, we review the biochemical mechanisms by which CO2 engages in peroxide-dependent reactions, free radical production, redox signaling, and oxidative damage. First, we cover the metabolic formation of CO2 and its connection to peroxide formation and decomposition. Next, the reaction mechanisms, kinetics, and processes by which the CO2/peroxide interplay modulates mammalian cell redox biology are scrutinized in-depth. Importantly, CO2 also regulates gene expression related to redox and nitric oxide metabolism and as such influences oxidative and inflammatory processes. Accumulated biochemical evidence in vitro, in cellula, and in vivo unambiguously show that the CO2 and peroxide metabolic pathways are intertwined and together participate in key redox events in mammalian cells.
Collapse
Affiliation(s)
- Rafael Radi
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
| |
Collapse
|
6
|
Pawloski W, Komiyama T, Kougentakis C, Majumdar A, Fushman D. Site-Specific Detection and Characterization of Ubiquitin Carbamylation. Biochemistry 2022; 61:712-721. [PMID: 35380792 PMCID: PMC9173829 DOI: 10.1021/acs.biochem.2c00085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The physiological consequences of varying in vivo CO2 levels point to a general mechanism for CO2 to influence cellular homeostasis beyond regulating pH. Aside from a few instances where CO2 has been observed to cause post-translational protein modification, by forming long-lived carbamates, little is known about how transitory and ubiquitous carbamylation events could induce a physiological response. Ubiquitin is a versatile protein involved in a multitude of cellular signaling pathways as polymeric chains of various lengths formed through one of the seven lysines or N-terminal amine. Unique polyubiquitin (polyUb) compositions present recognition signals for specific ubiquitin-receptors which enables this one protein to be involved in many different cellular processes. Advances in proteomic methods have allowed the capture and identification of protein carbamates in vivo, and Ub was found carbamylated at lysines K48 and K33. This was shown to negatively regulate ubiquitin-mediated signaling by inhibiting polyUb chain formation. Here, we expand upon these observations by characterizing the carbamylation susceptibility for all Ub amines simultaneously. Using NMR methods which directly probe 15N resonances, we determined carbamylation rates under various environmental conditions and related them to the intrinsic pKas. Our results show that the relatively low pKas for half of the Ub amines are correlated with enhanced susceptibility to carbamylation under physiological conditions. Two of these carbamylated amines, not observed by chemical capture, appear to be physiologically relevant post-translational modifications. These findings point to a mechanism for varying the levels of CO2 due to intracellular localization, cellular stresses, and metabolism to affect certain polyUb-mediated signaling pathways.
Collapse
Affiliation(s)
- Westley Pawloski
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland 20742, United States
| | - Teppei Komiyama
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland 20742, United States
| | - Christos Kougentakis
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David Fushman
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland 20742, United States
| |
Collapse
|
7
|
Carbon dioxide levels in neonates: what are safe parameters? Pediatr Res 2022; 91:1049-1056. [PMID: 34230621 PMCID: PMC9122818 DOI: 10.1038/s41390-021-01473-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 02/01/2023]
Abstract
There is no consensus on the optimal pCO2 levels in the newborn. We reviewed the effects of hypercapnia and hypocapnia and existing carbon dioxide thresholds in neonates. A systematic review was conducted in accordance with the PRISMA statement and MOOSE guidelines. Two hundred and ninety-nine studies were screened and 37 studies included. Covidence online software was employed to streamline relevant articles. Hypocapnia was associated with predominantly neurological side effects while hypercapnia was linked with neurological, respiratory and gastrointestinal outcomes and Retinpathy of prematurity (ROP). Permissive hypercapnia did not decrease periventricular leukomalacia (PVL), ROP, hydrocephalus or air leaks. As safe pCO2 ranges were not explicitly concluded in the studies chosen, it was indirectly extrapolated with reference to pCO2 levels that were found to increase the risk of neonatal disease. Although PaCO2 ranges were reported from 2.6 to 8.7 kPa (19.5-64.3 mmHg) in both term and preterm infants, there are little data on the safety of these ranges. For permissive hypercapnia, parameters described for bronchopulmonary dysplasia (BPD; PaCO2 6.0-7.3 kPa: 45.0-54.8 mmHg) and congenital diaphragmatic hernia (CDH; PaCO2 ≤ 8.7 kPa: ≤65.3 mmHg) were identified. Contradictory findings on the effectiveness of permissive hypercapnia highlight the need for further data on appropriate CO2 parameters and correlation with outcomes. IMPACT: There is no consensus on the optimal pCO2 levels in the newborn. There is no consensus on the effectiveness of permissive hypercapnia in neonates. A safe range of pCO2 of 5-7 kPa was inferred following systematic review.
Collapse
|
8
|
Wanandi SI, Arumsari S, Afitriansyah E, Syahrani RA, Dewantara IR, Nurachman LA, Amin IF, Haryono PD, Budiman K, Sugiharta AJ, Remedika AA, Tafikulhakim FH, Iswanti FC, Lee JY, Banerjee D. Elevated extracellular CO 2 level affects the adaptive transcriptional response and survival of human peripheral blood mononuclear cells toward hypoxia and oxidative stress. MEDICAL JOURNAL OF INDONESIA 2021. [DOI: 10.13181/mji.oa.203810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND High carbon dioxide (CO2) level from indoor environments, such as classrooms and offices, might cause sick building syndrome. Excessive indoor CO2 level increases CO2 level in the blood, and over-accumulation of CO2 induces an adaptive response that requires modulation of gene expression. This study aimed to investigate the adaptive transcriptional response toward hypoxia and oxidative stress in human peripheral blood mononuclear cells (PBMCs) exposed to elevated CO2 level in vitro and its association with cell viability.
METHODS PBMCs were treated in 5% CO2 and 15% CO2, representatives a high CO₂ level condition for 24 and 48 hours. Extracellular pH (pHe) was measured with a pH meter. The levels of reactive oxygen species were determined by measuring superoxide and hydrogen peroxide with dihydroethidium and dichlorofluorescin-diacetate assay. The mRNA expression levels of hypoxia-inducible factor (HIF)-1α, HIF-2α, nuclear factor (NF)-κB, and manganese superoxide dismutase (MnSOD) were analyzed using a real-time reverse transcriptase-polymerase chain reaction (qRT-PCR). Cell survival was determined by measuring cell viability.
RESULTS pHe increased in 24 hours after 15% CO₂ treatment, and then decreased in 48 hours. Superoxide and hydrogen peroxide levels increased after the 24- and 48-hour of high CO₂ level condition. The expression levels of NF-κB, MnSOD, HIF-1α, and HIF-2α decreased in 24 hours and increased in 48 hours. The increased antioxidant mRNA expression in 48 hours showed that the PBMCs were responsive under high CO2 conditions. Elevated CO2 suppressed cell viability significantly in 48 hours.
CONCLUSIONS After 48 hours of high CO₂ level condition, PBMCs showed an upregulation in genes related to hypoxia and oxidative stress to overcome the effects of CO2 elevation.
Collapse
|
9
|
Shigemura M, Welch LC, Sznajder JI. Hypercapnia Regulates Gene Expression and Tissue Function. Front Physiol 2020; 11:598122. [PMID: 33329047 PMCID: PMC7715027 DOI: 10.3389/fphys.2020.598122] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 10/26/2020] [Indexed: 01/20/2023] Open
Abstract
Carbon dioxide (CO2) is produced in eukaryotic cells primarily during aerobic respiration, resulting in higher CO2 levels in mammalian tissues than those in the atmosphere. CO2 like other gaseous molecules such as oxygen and nitric oxide, is sensed by cells and contributes to cellular and organismal physiology. In humans, elevation of CO2 levels in tissues and the bloodstream (hypercapnia) occurs during impaired alveolar gas exchange in patients with severe acute and chronic lung diseases. Advances in understanding of the biology of high CO2 effects reveal that the changes in CO2 levels are sensed in cells resulting in specific tissue responses. There is accumulating evidence on the transcriptional response to elevated CO2 levels that alters gene expression and activates signaling pathways with consequences for cellular and tissue functions. The nature of hypercapnia-responsive transcriptional regulation is an emerging area of research, as the responses to hypercapnia in different cell types, tissues, and species are not fully understood. Here, we review the current understanding of hypercapnia effects on gene transcription and consequent cellular and tissue functions.
Collapse
Affiliation(s)
- Masahiko Shigemura
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, United States
| | - Lynn C Welch
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, United States
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, United States
| |
Collapse
|
10
|
Shigemura M, Lecuona E, Angulo M, Dada LA, Edwards MB, Welch LC, Casalino-Matsuda SM, Sporn PHS, Vadász I, Helenius IT, Nader GA, Gruenbaum Y, Sharabi K, Cummins E, Taylor C, Bharat A, Gottardi CJ, Beitel GJ, Kaminski N, Budinger GRS, Berdnikovs S, Sznajder JI. Elevated CO 2 regulates the Wnt signaling pathway in mammals, Drosophila melanogaster and Caenorhabditis elegans. Sci Rep 2019; 9:18251. [PMID: 31796806 PMCID: PMC6890671 DOI: 10.1038/s41598-019-54683-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 11/14/2019] [Indexed: 12/03/2022] Open
Abstract
Carbon dioxide (CO2) is sensed by cells and can trigger signals to modify gene expression in different tissues leading to changes in organismal functions. Despite accumulating evidence that several pathways in various organisms are responsive to CO2 elevation (hypercapnia), it has yet to be elucidated how hypercapnia activates genes and signaling pathways, or whether they interact, are integrated, or are conserved across species. Here, we performed a large-scale transcriptomic study to explore the interaction/integration/conservation of hypercapnia-induced genomic responses in mammals (mice and humans) as well as invertebrates (Caenorhabditis elegans and Drosophila melanogaster). We found that hypercapnia activated genes that regulate Wnt signaling in mouse lungs and skeletal muscles in vivo and in several cell lines of different tissue origin. Hypercapnia-responsive Wnt pathway homologues were similarly observed in secondary analysis of available transcriptomic datasets of hypercapnia in a human bronchial cell line, flies and nematodes. Our data suggest the evolutionarily conserved role of high CO2 in regulating Wnt pathway genes.
Collapse
Affiliation(s)
- Masahiko Shigemura
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Emilia Lecuona
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Martín Angulo
- Pathophysiology Department, School of Medicine, Universidad de la República, Montevideo, Uruguay
| | - Laura A Dada
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Melanie B Edwards
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Lynn C Welch
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - S Marina Casalino-Matsuda
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Peter H S Sporn
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- Medical Service, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, United States of America
| | - István Vadász
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, and The Cardio-Pulmonary Institute, Giessen, Germany
| | - Iiro Taneli Helenius
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States of America
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, State College, PA, United States of America
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Kfir Sharabi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, United States of America
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States of America
| | - Eoin Cummins
- School of Medicine, Systems Biology Ireland and the Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Cormac Taylor
- School of Medicine, Systems Biology Ireland and the Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Ankit Bharat
- Division of Thoracic Surgery, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Cara J Gottardi
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Greg J Beitel
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States of America
| | - Naftali Kaminski
- Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States of America
| | - G R Scott Budinger
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Sergejs Berdnikovs
- Division of Allergy and Immunology, Feinberg School of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America.
| |
Collapse
|
11
|
Bunyatyan ND, Drogovoz SM, Kononenko AV, Prokofiev AB. [Carboxytherapy - an innovative trend in resort medicine]. VOPROSY KURORTOLOGII, FIZIOTERAPII, I LECHEBNOĬ FIZICHESKOĬ KULTURY 2019; 95:72-76. [PMID: 30412151 DOI: 10.17116/kurort20189505172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Carboxytherapy (the treatment based on carbon dioxide injections) is a multipurpose and widely used medical technology. The use of CO2 injections (intracutaneous, subcutaneous, and pneumopuncture) have substantially supplemented and increased the practical relevance of carboxytherapy as a method for the treatment of many diseases. Thanks to it physiological properties, CO2 has antihypoxic, antioxidant, vasodilatory, anti-inflammatory, analgesic, and spasmolytic activities; moreover, it improves blood viscosity, stimulates neoangiogenesis, and regenerative processes. Carbon dioxide is a sort of biochemical 'peacemaker' in tissue oxygenation: when blood cells are exposed to high CO2 concentrations (Bohr effect), the rate of gas exchange (CO2 and O2) increases. The human organism interprets carboxytherapy (local hypercapnia) as oxygen deficiency and responses to it by boosting not only the blood flow, but also the vascular endothelial growth factor which stimulates neoangiogenesis and in the long run improves blood supply and tissue trophism. The multiple mechanisms of action, polymodal efficacy, a tool kit with a wide range of detectors and various modes of treatment make carboxytherapy a popular medical technology all over the world, namely in cosmetology, dermatology, aesthetic medicine, angiology, orthopaedics, cardiology, neurology, pulmonology, gynaecology, urology, proctology, plastic and general surgery, and other areas. Carboxytherapy provides a perfect example of the off-label usage in medicine that made it one of the most extensively applied medical technology for the treatment of various diseases despite the lack of the preclinical data and scarce relevant information available in textbooks, reference books and booklets.
Collapse
Affiliation(s)
- N D Bunyatyan
- I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Federal State Budgetary Institution "Scientific Centre for Expert Evaluation of Medicinal Products" of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - S M Drogovoz
- National University of Pharmacy, Kharkiv, Ukraine
| | | | - A B Prokofiev
- I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Private Dermatovenerologic Clinic, Svidnik, Slovak Republic; Federal State Budgetary Institution "Scientific Centre for Expert Evaluation of Medicinal Products" of the Ministry of Health of the Russian Federation, Moscow, Russia
| |
Collapse
|
12
|
Instructive microenvironments in skin wound healing: Biomaterials as signal releasing platforms. Adv Drug Deliv Rev 2018; 129:95-117. [PMID: 29627369 DOI: 10.1016/j.addr.2018.03.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/16/2018] [Accepted: 03/27/2018] [Indexed: 12/16/2022]
Abstract
Skin wound healing aims to repair and restore tissue through a multistage process that involves different cells and signalling molecules that regulate the cellular response and the dynamic remodelling of the extracellular matrix. Nowadays, several therapies that combine biomolecule signals (growth factors and cytokines) and cells are being proposed. However, a lack of reliable evidence of their efficacy, together with associated issues such as high costs, a lack of standardization, no scalable processes, and storage and regulatory issues, are hampering their application. In situ tissue regeneration appears to be a feasible strategy that uses the body's own capacity for regeneration by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the wound site to promote repair and regeneration. The aim is to engineer instructive systems to regulate the spatio-temporal delivery of proper signalling based on the biological mechanisms of the different events that occur in the host microenvironment. This review describes the current state of the different signal cues used in wound healing and skin regeneration, and their combination with biomaterial supports to create instructive microenvironments for wound healing.
Collapse
|
13
|
Keogh CE, Scholz CC, Rodriguez J, Selfridge AC, von Kriegsheim A, Cummins EP. Carbon dioxide-dependent regulation of NF-κB family members RelB and p100 gives molecular insight into CO 2-dependent immune regulation. J Biol Chem 2017; 292:11561-11571. [PMID: 28507099 DOI: 10.1074/jbc.m116.755090] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 05/12/2017] [Indexed: 12/31/2022] Open
Abstract
CO2 is a physiological gas normally produced in the body during aerobic respiration. Hypercapnia (elevated blood pCO2 >≈50 mm Hg) is a feature of several lung pathologies, e.g. chronic obstructive pulmonary disease. Hypercapnia is associated with increased susceptibility to bacterial infections and suppression of inflammatory signaling. The NF-κB pathway has been implicated in these effects; however, the molecular mechanisms underpinning cellular sensitivity of the NF-κB pathway to CO2 are not fully elucidated. Here, we identify several novel CO2-dependent changes in the NF-κB pathway. NF-κB family members p100 and RelB translocate to the nucleus in response to CO2 A cohort of RelB protein-protein interactions (e.g. with Raf-1 and IκBα) are altered by CO2 exposure, although others are maintained (e.g. with p100). RelB is processed by CO2 in a manner dependent on a key C-terminal domain located in its transactivation domain. Loss of the RelB transactivation domain alters NF-κB-dependent transcriptional activity, and loss of p100 alters sensitivity of RelB to CO2 Thus, we provide molecular insight into the CO2 sensitivity of the NF-κB pathway and implicate altered RelB/p100-dependent signaling in the CO2-dependent regulation of inflammatory signaling.
Collapse
Affiliation(s)
- Ciara E Keogh
- From the School of Medicine and Conway Institute and
| | - Carsten C Scholz
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Institute of Physiology, University of Zürich, CH-8057 Zürich, Switzerland
| | - Javier Rodriguez
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Edinburgh Cancer Research Centre, Edinburgh EH4 2XR, Scotland, United Kingdom, and
| | | | - Alexander von Kriegsheim
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Edinburgh Cancer Research Centre, Edinburgh EH4 2XR, Scotland, United Kingdom, and
| | | |
Collapse
|
14
|
Eftedal I, Flatberg A, Drvis I, Dujic Z. Immune and inflammatory responses to freediving calculated from leukocyte gene expression profiles. Physiol Genomics 2016; 48:795-802. [PMID: 27614202 DOI: 10.1152/physiolgenomics.00048.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/08/2016] [Indexed: 12/31/2022] Open
Abstract
Freedivers hold their breath while diving, causing blood oxygen levels to decrease (hypoxia) while carbon dioxide increases (hypercapnia). Whereas blood gas changes are presumably involved in the progression of respiratory diseases, less is known about their effect on healthy individuals. Here we have used gene expression profiling to analyze elite athletes' immune and inflammatory responses to freediving. Blood was collected before and 1 and 3 h after a series of maximal dynamic and static freediving apneas in a pool, and peripheral blood gene expression was mapped on genome-wide microarrays. Fractions of phenotypically distinct immune cells were computed by deconvolution of the gene expression data using Cibersort software. Changes in gene activity and associated biological pathways were determined using R and GeneGo software. The results indicated a temporary increase of neutrophil granulocytes, and a decrease of cytotoxic lymphocytes; i.e., CD8+ T cells and resting NK cells. Biological pathway associations indicated possible protective reactions: genes involved in anti-inflammatory responses to proresolving lipid mediators were upregulated, whereas central factors involved in granule-mediated lymphocyte cytotoxicity were downregulated. While it remains unresolved whether freediving alters the immune system's defensive function, these results provide new insight into leukocyte responses and the protection of homeostasis in healthy athletes.
Collapse
Affiliation(s)
- Ingrid Eftedal
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway;
| | - Arnar Flatberg
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology Microarray Core Facility, Trondheim, Norway
| | - Ivan Drvis
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia; and
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| |
Collapse
|
15
|
Filatova A, Seidel S, Böğürcü N, Gräf S, Garvalov BK, Acker T. Acidosis Acts through HSP90 in a PHD/VHL-Independent Manner to Promote HIF Function and Stem Cell Maintenance in Glioma. Cancer Res 2016; 76:5845-5856. [PMID: 27488520 DOI: 10.1158/0008-5472.can-15-2630] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 07/13/2016] [Indexed: 11/16/2022]
Abstract
Hypoxia is a common feature of solid tumors, which controls multiple aspects of cancer progression. One important function of hypoxia and the hypoxia-inducible factors (HIF) is the maintenance of cancer stem-like cells (CSC), a population of tumor cells that possess stem cell-like properties and drives tumor growth. Among the changes promoted by hypoxia is a metabolic shift resulting in acidification of the tumor microenvironment. Here, we show that glioma hypoxia and acidosis functionally cooperate in inducing HIF transcription factors and CSC maintenance. We found that these effects did not involve the classical PHD/VHL pathway for HIF upregulation, but instead involved the stress-induced chaperone protein HSP90. Genetic or pharmacologic inactivation of HSP90 inhibited the increase in HIF levels and abolished the self-renewal and tumorigenic properties of CSCs induced by acidosis. In clinical specimens of glioma, HSP90 was upregulated in the hypoxic niche and was correlated with a CSC phenotype. Our findings highlight the role of tumor acidification within the hypoxic niche in the regulation of HIF and CSC function through HSP90, with implications for therapeutic strategies to target CSC in gliomas and other hypoxic tumors. Cancer Res; 76(19); 5845-56. ©2016 AACR.
Collapse
Affiliation(s)
- Alina Filatova
- Institute of Neuropathology, University of Giessen, Giessen, Germany
| | - Sascha Seidel
- Institute of Neuropathology, University of Giessen, Giessen, Germany. Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Frankfurt, Germany
| | - Nuray Böğürcü
- Institute of Neuropathology, University of Giessen, Giessen, Germany
| | - Sabine Gräf
- Institute of Neuropathology, University of Giessen, Giessen, Germany
| | - Boyan K Garvalov
- Institute of Neuropathology, University of Giessen, Giessen, Germany
| | - Till Acker
- Institute of Neuropathology, University of Giessen, Giessen, Germany.
| |
Collapse
|
16
|
Cummins EP, Keogh CE. Respiratory gases and the regulation of transcription. Exp Physiol 2016; 101:986-1002. [DOI: 10.1113/ep085715] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/23/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Eoin P. Cummins
- School of Medicine; University College Dublin; Belfield 4 Dublin Ireland
| | - Ciara E. Keogh
- School of Medicine; University College Dublin; Belfield 4 Dublin Ireland
| |
Collapse
|
17
|
Taylor CT, Doherty G, Fallon PG, Cummins EP. Hypoxia-dependent regulation of inflammatory pathways in immune cells. J Clin Invest 2016; 126:3716-3724. [PMID: 27454299 DOI: 10.1172/jci84433] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Uncontrolled inflammation underpins a diverse range of diseases where effective therapy remains an unmet clinical need. Hypoxia is a prominent feature of the inflammatory microenvironment that regulates key transcription factors including HIF and NF-κB in both innate and adaptive immune cells. In turn, altered activity of the pathways controlled by these factors can affect the course of inflammation through the regulation of immune cell development and function. In this review, we will discuss these pathways and the oxygen sensors that confer hypoxic sensitivity in immune cells. Furthermore, we will describe how hypoxia-dependent pathways contribute to immunity and discuss their potential as therapeutic targets in inflammatory and infectious disease.
Collapse
|
18
|
Selfridge AC, Cavadas MAS, Scholz CC, Campbell EL, Welch LC, Lecuona E, Colgan SP, Barrett KE, Sporn PHS, Sznajder JI, Cummins EP, Taylor CT. Hypercapnia Suppresses the HIF-dependent Adaptive Response to Hypoxia. J Biol Chem 2016; 291:11800-8. [PMID: 27044749 DOI: 10.1074/jbc.m116.713941] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 01/18/2023] Open
Abstract
Molecular oxygen and carbon dioxide are the primary gaseous substrate and product of oxidative metabolism, respectively. Hypoxia (low oxygen) and hypercapnia (high carbon dioxide) are co-incidental features of the tissue microenvironment in a range of pathophysiologic states, including acute and chronic respiratory diseases. The hypoxia-inducible factor (HIF) is the master regulator of the transcriptional response to hypoxia; however, little is known about the impact of hypercapnia on gene transcription. Because of the relationship between hypoxia and hypercapnia, we investigated the effect of hypercapnia on the HIF pathway. Hypercapnia suppressed HIF-α protein stability and HIF target gene expression both in mice and cultured cells in a manner that was at least in part independent of the canonical O2-dependent HIF degradation pathway. The suppressive effects of hypercapnia on HIF-α protein stability could be mimicked by reducing intracellular pH at a constant level of partial pressure of CO2 Bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase that blocks lysosomal degradation, prevented the hypercapnic suppression of HIF-α protein. Based on these results, we hypothesize that hypercapnia counter-regulates activation of the HIF pathway by reducing intracellular pH and promoting lysosomal degradation of HIF-α subunits. Therefore, hypercapnia may play a key role in the pathophysiology of diseases where HIF is implicated.
Collapse
Affiliation(s)
| | - Miguel A S Cavadas
- Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carsten C Scholz
- From the School of Medicine and Medical Science, Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland, the Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Eric L Campbell
- the University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Lynn C Welch
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Emilia Lecuona
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Sean P Colgan
- the University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Kim E Barrett
- From the School of Medicine and Medical Science, Conway Institute, and
| | - Peter H S Sporn
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and the Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
| | - Jacob I Sznajder
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Eoin P Cummins
- From the School of Medicine and Medical Science, Conway Institute, and
| | - Cormac T Taylor
- From the School of Medicine and Medical Science, Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland,
| |
Collapse
|
19
|
Downs CJ, Pinshow B, Khokhlova IS, Krasnov BR. Flea fitness is reduced by high fractional concentrations of CO₂ that simulate levels found in their hosts' burrows. J Exp Biol 2015; 218:3596-603. [PMID: 26582933 DOI: 10.1242/jeb.122812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nidicolous ectoparasites such as fleas and gamasid mites that feed on small and medium-sized mammals spend much of their time in their hosts' burrows, which provide an environment for living, and often feeding, to their pre-imaginal and/or adult stages. Thus, these ectoparasites should be adapted to environmental conditions in burrows, including high fractional concentrations of CO2 (F(CO2)). We examined how a high F(CO2) (0.04) affected survival and reproductive success of a hematophagous ectoparasite of burrowing rodents using fleas Xenopsylla ramesis and Sundevall's jirds Meriones crassus. In the first experiment, fleas fed on hosts housed in high-CO2 (F(CO2) =0.04) or atmospheric-CO2 (F(CO2) ≈0.0004) air, and were allowed to breed. In a second experiment, fleas were maintained in high CO2 or CO2-free air with no hosts to determine how CO2 levels affect survival and activity levels. We found that at high F(CO2) fleas laid fewer eggs, reducing reproductive success. In addition, at high F(CO2), activity levels and survival of fleas were reduced. Our results indicate that fleas do not perform well in the F(CO2) used in this experiment. Previous research indicated that the type and intensity of the effects of CO2 concentration on the fitness of an insect depend on the F(CO2) used, so we advise caution when generalizing inferences drawn to insects exposed to other F(CO2). If, however, F(CO2) found in natural mammal burrows brings about reduced fitness in fleas in general, then burrowing hosts may benefit from reduced parasite infestation if burrow air F(CO2) is high.
Collapse
Affiliation(s)
- Cynthia J Downs
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel
| | - Berry Pinshow
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel
| | - Irina S Khokhlova
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel
| |
Collapse
|
20
|
Abstract
The genetic basis of type 2 diabetes remains incompletely defined despite the use of multiple genetic strategies. Multiparental populations such as heterogeneous stocks (HS) facilitate gene discovery by allowing fine mapping to only a few megabases, significantly decreasing the number of potential candidate genes compared to traditional mapping strategies. In the present work, we employed expression and sequence analysis in HS rats (Rattus norvegicus) to identify Tpcn2 as a likely causal gene underlying a 3.1-Mb locus for glucose and insulin levels. Global gene expression analysis on liver identified Tpcn2 as the only gene in the region that is differentially expressed between HS rats with glucose intolerance and those with normal glucose regulation. Tpcn2 also maps as a cis-regulating expression QTL and is negatively correlated with fasting glucose levels. We used founder sequence to identify variants within this region and assessed association between 18 variants and diabetic traits by conducting a mixed-model analysis, accounting for the complex family structure of the HS. We found that two variants were significantly associated with fasting glucose levels, including a nonsynonymous coding variant within Tpcn2. Studies in Tpcn2 knockout mice demonstrated a significant decrease in fasting glucose levels and insulin response to a glucose challenge relative to those in wild-type mice. Finally, we identified variants within Tpcn2 that are associated with fasting insulin in humans. These studies indicate that Tpcn2 is a likely causal gene that may play a role in human diabetes and demonstrate the utility of multiparental populations for positionally cloning genes within complex loci.
Collapse
|
21
|
Kruse CR, Nuutila K, Lee CCY, Kiwanuka E, Singh M, Caterson EJ, Eriksson E, Sørensen JA. The external microenvironment of healing skin wounds. Wound Repair Regen 2015; 23:456-64. [PMID: 25857996 DOI: 10.1111/wrr.12303] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 04/02/2015] [Indexed: 11/28/2022]
Abstract
The skin wound microenvironment can be divided into two main components that influence healing: the external wound microenvironment, which is outside the wound surface; and the internal wound microenvironment, underneath the surface, to which the cells within the wound are exposed. Treatment methods that directly alter the features of the external wound microenvironment indirectly affect the internal wound microenvironment due to the exchange between the two compartments. In this review, we focus on the effects of temperature, pressure (positive and negative), hydration, gases (oxygen and carbon dioxide), pH, and anti-microbial treatment on the wound. These factors are well described in the literature and can be modified with treatment methods available in the clinic. Understanding the roles of these factors in wound pathophysiology is of central importance in wound treatment.
Collapse
Affiliation(s)
- Carla R Kruse
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Department of Plastic and Reconstructive Surgery, Odense University Hospital, Odense, Denmark
| | - Kristo Nuutila
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Cameron C Y Lee
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth Kiwanuka
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Mansher Singh
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Edward J Caterson
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elof Eriksson
- Division of Plastic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jens A Sørensen
- Department of Plastic and Reconstructive Surgery, Odense University Hospital, Odense, Denmark
| |
Collapse
|
22
|
Quaye IK. Extracellular hemoglobin: the case of a friend turned foe. Front Physiol 2015; 6:96. [PMID: 25941490 PMCID: PMC4403290 DOI: 10.3389/fphys.2015.00096] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/12/2015] [Indexed: 12/14/2022] Open
Abstract
Hemoglobin (Hb) is a highly conserved molecule present in all life forms and functionally tied to the complexity of aerobic organisms on earth in utilizing oxygen from the atmosphere and delivering to cells and tissues. This primary function sustains the energy requirements of cells and maintains cellular homeostasis. Decades of intensive research has presented a paradigm shift that shows how the molecule also functions to facilitate smooth oxygen delivery through the cardiovascular system for cellular bioenergetic homeostasis and signaling for cell function and defense. These roles are particularly highlighted in the binding of Hb to gaseous molecules carbon dioxide (CO2), nitric oxide (NO) and carbon monoxide (CO), while also serving indirectly or directly as sources of these signaling molecules. The functional activities impacted by Hb outside of bioenergetics homeostasis, include fertilization, signaling functions, modulation of inflammatory responses for defense and cell viability. These activities are efficiently executed while Hb is sequestered safely within the confines of the red blood cell (rbc). Outside of rbc confines, Hb disaggregates and becomes a danger molecule to cell survival. In these perpectives, Hb function is broadly dichotomous, either a friend in its natural environment providing and facilitating the means for cell function or foe when dislocated from its habitat under stress or pathological condition disrupting cell function. The review presents insights into how this dichotomy in function manifests.
Collapse
Affiliation(s)
- Isaac K Quaye
- Department of Biochemistry, University of Namibia School of Medicine Windhoek, Namibia
| |
Collapse
|
23
|
Chiu S, Kanter J, Sun H, Bharat A, Sporn PHS, Bharat A. Effects of Hypercapnia in Lung Tissue Repair and Transplant. CURRENT TRANSPLANTATION REPORTS 2015. [DOI: 10.1007/s40472-014-0047-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
24
|
Beitler JR, Hubmayr RD, Malhotra A. CrossTalk opposing view: there is not added benefit to providing permissive hypercapnia in the treatment of ARDS. J Physiol 2013; 591:2767-9. [PMID: 23729791 DOI: 10.1113/jphysiol.2013.252619] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jeremy R Beitler
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Boston, MA, USA.
| | | | | |
Collapse
|
25
|
Cummins EP, Selfridge AC, Sporn PH, Sznajder JI, Taylor CT. Carbon dioxide-sensing in organisms and its implications for human disease. Cell Mol Life Sci 2013; 71:831-45. [PMID: 24045706 DOI: 10.1007/s00018-013-1470-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/22/2013] [Accepted: 08/30/2013] [Indexed: 12/29/2022]
Abstract
The capacity of organisms to sense changes in the levels of internal and external gases and to respond accordingly is central to a range of physiologic and pathophysiologic processes. Carbon dioxide, a primary product of oxidative metabolism is one such gas that can be sensed by both prokaryotic and eukaryotic cells and in response to altered levels, elicit the activation of multiple adaptive pathways. The outcomes of activating CO2-sensitive pathways in various species include increased virulence of fungal and bacterial pathogens, prey-seeking behavior in insects as well as taste perception, lung function, and the control of immunity in mammals. In this review, we discuss what is known about the mechanisms underpinning CO2 sensing across a range of species and consider the implications of this for physiology, disease progression, and the possibility of developing new therapeutics for inflammatory and infectious disease.
Collapse
Affiliation(s)
- Eoin P Cummins
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | | | | | | | | |
Collapse
|
26
|
Dowlaty N, Yoon A, Galassetti P. Monitoring states of altered carbohydrate metabolism via breath analysis: are times ripe for transition from potential to reality? Curr Opin Clin Nutr Metab Care 2013; 16:466-72. [PMID: 23739629 PMCID: PMC4060961 DOI: 10.1097/mco.0b013e328361f91f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW To introduce the potential of breath analysis as a diagnostic or monitoring tool in diabetes. RECENT FINDINGS Blood testing for plasma glucose and other metabolic variables is the base for the diagnosis and management of diabetes, whose two main types (type 1 and type 2, T1DM, T2DM) are projected to affect 450 million by 2030. As blood testing is often uncomfortable, painful, costly, and in some situations unreliable, the quest for alternative, noninvasive methods has been ongoing for decades. Breath analysis has emerged as an ideal alternative as sample collection is easy, painless, flexible, noninvasive, practical, and inexpensive. No single exhaled gas can reflect systemic glucose concentrations. Multiple gases, however, have been linked to various aspects of glucose metabolism, and integrated analysis of their simultaneous profiles during prolonged glycemic fluctuations has yielded accurate predictions of plasma values, building expectation that a clinically usable breath-based glucometer may be developed within a few years. SUMMARY While prototypes of hand-held breath testing glucometers may still be several years away, current research shows the imminent promise of this methodology and the widening support for its development.
Collapse
Affiliation(s)
- Newsha Dowlaty
- Institute for Clinical and Translational Science, University of California, Irvine, California 92697, USA
| | | | | |
Collapse
|
27
|
Eckle T, Hughes K, Ehrentraut H, Brodsky KS, Rosenberger P, Choi DS, Ravid K, Weng T, Xia Y, Blackburn MR, Eltzschig HK. Crosstalk between the equilibrative nucleoside transporter ENT2 and alveolar Adora2b adenosine receptors dampens acute lung injury. FASEB J 2013; 27:3078-89. [PMID: 23603835 DOI: 10.1096/fj.13-228551] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The signaling molecule adenosine has been implicated in attenuating acute lung injury (ALI). Adenosine signaling is terminated by its uptake through equilibrative nucleoside transporters (ENTs). We hypothesized that ENT-dependent adenosine uptake could be targeted to enhance adenosine-mediated lung protection. To address this hypothesis, we exposed mice to high-pressure mechanical ventilation to induce ALI. Initial studies demonstrated time-dependent repression of ENT1 and ENT2 transcript and protein levels during ALI. To examine the contention that ENT repression represents an endogenous adaptive response, we performed functional studies with the ENT inhibitor dipyridamole. Dipyridamole treatment (1 mg/kg; EC50=10 μM) was associated with significant increases in ALI survival time (277 vs. 395 min; P<0.05). Subsequent studies in gene-targeted mice for Ent1 or Ent2 revealed a selective phenotype in Ent2(-/-) mice, including attenuated pulmonary edema and improved gas exchange during ALI in conjunction with elevated adenosine levels in the bronchoalveolar fluid. Furthermore, studies in genetic models for adenosine receptors implicated the A2B adenosine receptor (Adora2b) in mediating ENT-dependent lung protection. Notably, dipyridamole-dependent attenuation of lung inflammation was abolished in mice with alveolar epithelial Adora2b gene deletion. Our newly identified crosstalk pathway between ENT2 and alveolar epithelial Adora2b in lung protection during ALI opens possibilities for combined therapies targeted to this protein set.
Collapse
Affiliation(s)
- Tobias Eckle
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado School of Medicine, 12700 E. 19th Ave., Aurora, CO 80045, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Minh TDC, Blake DR, Galassetti PR. The clinical potential of exhaled breath analysis for diabetes mellitus. Diabetes Res Clin Pract 2012; 97:195-205. [PMID: 22410396 PMCID: PMC3384765 DOI: 10.1016/j.diabres.2012.02.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 02/02/2012] [Accepted: 02/12/2012] [Indexed: 01/15/2023]
Abstract
Various compounds in present human breath have long been loosely associated with pathological states (including acetone smell in uncontrolled diabetes). Only recently, however, the precise measurement of exhaled volatile organic compounds (VOCs) and aerosolized particles was made possible at extremely low concentrations by advances in several analytical methodologies, described in detail in the international literature and each suitable for specific subsets of exhaled compounds. Exhaled gases may be generated endogenously (in the pulmonary tract, blood, or peripheral tissues), as metabolic by-products of human cells or colonizing micro-organisms, or may be inhaled as atmospheric pollutants; growing evidence indicates that several of these molecules have distinct cell-to-cell signaling functions. Independent of origin and physiological role, exhaled VOCs are attractive candidates as biomarkers of cellular activity/metabolism, and could be incorporated in future non-invasive clinical testing devices. Indeed, several recent studies reported altered exhaled gas profiles in dysmetabolic conditions and relatively accurate predictions of glucose concentrations, at least in controlled experimental conditions, for healthy and diabetic subjects over a broad range of glycemic values. Optimization of this methodology and validation in large-scale trials under a wider range of conditions is needed to determine its true potential to transition into practical clinical use.
Collapse
Affiliation(s)
- Timothy Do Chau Minh
- Department of Pharmacology, University of California, Irvine, Irvine, CA 92697-1385, United States.
| | | | | |
Collapse
|
29
|
Cook ZC, Gray MA, Cann MJ. Elevated carbon dioxide blunts mammalian cAMP signaling dependent on inositol 1,4,5-triphosphate receptor-mediated Ca2+ release. J Biol Chem 2012; 287:26291-301. [PMID: 22654111 PMCID: PMC3406713 DOI: 10.1074/jbc.m112.349191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 05/15/2012] [Indexed: 12/11/2022] Open
Abstract
Elevated CO(2) is generally detrimental to animal cells, suggesting an interaction with core processes in cell biology. We demonstrate that elevated CO(2) blunts G protein-activated cAMP signaling. The effect of CO(2) is independent of changes in intracellular and extracellular pH, independent of the mechanism used to activate the cAMP signaling pathway, and is independent of cell context. A combination of pharmacological and genetic tools demonstrated that the effect of elevated CO(2) on cAMP levels required the activity of the IP(3) receptor. Consistent with these findings, CO(2) caused an increase in steady state cytoplasmic Ca(2+) concentrations not observed in the absence of the IP(3) receptor or under nonspecific acidotic conditions. We examined the well characterized cAMP-dependent inhibition of the isoform 3 Na(+)/H(+) antiporter (NHE3) to demonstrate a functional relevance for CO(2)-mediated reductions in cellular cAMP. Consistent with the cellular biochemistry, elevated CO(2) abrogated the inhibitory effect of cAMP on NHE3 function via an IP(3) receptor-dependent mechanism.
Collapse
Affiliation(s)
- Zara C. Cook
- From the School of Biological and Biomedical Sciences and
- Biophysical Sciences Institute, Durham University, South Road, Durham DH1 3LE, United Kingdom and
| | - Michael A. Gray
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Martin J. Cann
- From the School of Biological and Biomedical Sciences and
- Biophysical Sciences Institute, Durham University, South Road, Durham DH1 3LE, United Kingdom and
| |
Collapse
|
30
|
Carotid chemoreceptor development and neonatal apnea. Respir Physiol Neurobiol 2012; 185:170-6. [PMID: 22842008 DOI: 10.1016/j.resp.2012.07.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/29/2012] [Accepted: 07/19/2012] [Indexed: 01/28/2023]
Abstract
The premature transition from fetal to neonatal life is accompanied by an immature respiratory neural control system. Most preterm infants exhibit recurrent apnea, resulting in repetitive oscillations in O(2) saturation (intermittent hypoxia, IH). Numerous factors are likely to play a role in the etiology of apnea including inputs from the carotid chemoreceptors. Despite major advances in our understanding of carotid chemoreceptor function in the early neonatal period, however, their contribution to the initiation of an apneic event and its eventual termination are still largely speculative. Recent findings have provided a detailed account of the postnatal changes in the incidence of hypoxemic events associated with apnea, and there is anecdotal evidence for a positive correlation with carotid chemoreceptor maturation. Furthermore, studies on non-human animal models have shown that chronic IH sensitizes the carotid chemoreceptors, which has been proposed to perpetuate the occurrence of apnea. An alternative hypothesis is that sensitization of the carotid chemoreceptors could represent an important protective mechanism to defend against severe hypoxemia. The purpose of this review, therefore, is to discuss how the carotid chemoreceptors may contribute to the initiation and termination of an apneic event in the neonate and the use of xanthine therapy in the prevention of apnea.
Collapse
|
31
|
Oliver KM, Lenihan CR, Bruning U, Cheong A, Laffey JG, McLoughlin P, Taylor CT, Cummins EP. Hypercapnia induces cleavage and nuclear localization of RelB protein, giving insight into CO2 sensing and signaling. J Biol Chem 2012; 287:14004-11. [PMID: 22396550 PMCID: PMC3340129 DOI: 10.1074/jbc.m112.347971] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Carbon dioxide (CO2) is increasingly being appreciated as an intracellular signaling molecule that affects inflammatory and immune responses. Elevated arterial CO2 (hypercapnia) is encountered in a range of clinical conditions, including chronic obstructive pulmonary disease, and as a consequence of therapeutic ventilation in acute respiratory distress syndrome. In patients suffering from this syndrome, therapeutic hypoventilation strategy designed to reduce mechanical damage to the lungs is accompanied by systemic hypercapnia and associated acidosis, which are associated with improved patient outcome. However, the molecular mechanisms underlying the beneficial effects of hypercapnia and the relative contribution of elevated CO2 or associated acidosis to this response remain poorly understood. Recently, a role for the non-canonical NF-κB pathway has been postulated to be important in signaling the cellular transcriptional response to CO2. In this study, we demonstrate that in cells exposed to elevated CO2, the NF-κB family member RelB was cleaved to a lower molecular weight form and translocated to the nucleus in both mouse embryonic fibroblasts and human pulmonary epithelial cells (A549). Furthermore, elevated nuclear RelB was observed in vivo and correlated with hypercapnia-induced protection against LPS-induced lung injury. Hypercapnia-induced RelB processing was sensitive to proteasomal inhibition by MG-132 but was independent of the activity of glycogen synthase kinase 3β or MALT-1, both of which have been previously shown to mediate RelB processing. Taken together, these data demonstrate that RelB is a CO2-sensitive NF-κB family member that may contribute to the beneficial effects of hypercapnia in inflammatory diseases of the lung.
Collapse
Affiliation(s)
- Kathryn M Oliver
- School of Medicine and Medical Science, UCD Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Wiernicki I. A commentary on the paper titled "protease activity in the multi-layered intra-luminal thrombus of abdominal aortic aneurysms" for Atherosclerosis. Atherosclerosis 2011; 218:283-4. [PMID: 21737078 DOI: 10.1016/j.atherosclerosis.2011.05.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 05/31/2011] [Indexed: 11/24/2022]
Affiliation(s)
- Ireneusz Wiernicki
- Pomeranian Medical University, Department of Vascular Surgery and Angiology, Szczecin, Poland.
| |
Collapse
|
33
|
Huxtable AG, Vinit S, Windelborn JA, Crader SM, Guenther CH, Watters JJ, Mitchell GS. Systemic inflammation impairs respiratory chemoreflexes and plasticity. Respir Physiol Neurobiol 2011; 178:482-9. [PMID: 21729770 DOI: 10.1016/j.resp.2011.06.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 11/18/2022]
Abstract
Many lung and central nervous system disorders require robust and appropriate physiological responses to assure adequate breathing. Factors undermining the efficacy of ventilatory control will diminish the ability to compensate for pathology, threatening life itself. Although most of these same disorders are associated with systemic and/or neuroinflammation, and inflammation affects neural function, we are only beginning to understand interactions between inflammation and any aspect of ventilatory control (e.g. sensory receptors, rhythm generation, chemoreflexes, plasticity). Here we review available evidence, and present limited new data suggesting that systemic (or neural) inflammation impairs two key elements of ventilatory control: chemoreflexes and respiratory motor (versus sensory) plasticity. Achieving an understanding of mechanisms whereby inflammation undermines ventilatory control is fundamental since inflammation may diminish the capacity for natural, compensatory responses during pathological states, and the ability to harness respiratory plasticity as a therapeutic strategy in the treatment of devastating breathing disorders, such as during cervical spinal injury or motor neuron disease.
Collapse
Affiliation(s)
- A G Huxtable
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, United States
| | | | | | | | | | | | | |
Collapse
|
34
|
Chao J, Wood JG, Gonzalez NC. Alveolar macrophages initiate the systemic microvascular inflammatory response to alveolar hypoxia. Respir Physiol Neurobiol 2011; 178:439-48. [PMID: 21402178 DOI: 10.1016/j.resp.2011.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 03/03/2011] [Accepted: 03/07/2011] [Indexed: 01/01/2023]
Abstract
Alveolar hypoxia occurs as a result of a decrease in the environmental [Formula: see text] , as in altitude, or in clinical conditions associated with a global or regional decrease in alveolar ventilation. Systemic effects, in most of which an inflammatory component has been identified, frequently accompany both acute and chronic forms of alveolar hypoxia. Experimentally, it has been shown that acute exposure to environmental hypoxia causes a widespread systemic inflammatory response in rats and mice. Recent research has demonstrated that alveolar macrophages, in addition to their well known intrapulmonary functions, have systemic, extrapulmonary effects when activated, and indirect evidence suggest these cells may play a role in the systemic consequences of alveolar hypoxia. This article reviews studies showing that the systemic inflammation of acute alveolar hypoxia observed in rats is not initiated by the low systemic tissue [Formula: see text] , but rather by a chemokine, Monocyte Chemoattractant Protein-1 (MCP-1, or CCL2) released by alveolar macrophages stimulated by hypoxia and transported by the circulation. Circulating MCP-1, in turn, activates perivascular mast cells to initiate the microvascular inflammatory cascade. The research reviewed here highlights the extrapulmonary effects of alveolar macrophages and provides a possible mechanism for some of the systemic effects of alveolar hypoxia.
Collapse
Affiliation(s)
- Jie Chao
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | | |
Collapse
|