1
|
Feng J, Liu L, Liu J, Wang J. Immunological alterations in the endothelial barrier: a new predictive and therapeutic paradigm for sepsis. Expert Rev Clin Immunol 2024; 20:1205-1217. [PMID: 38850066 DOI: 10.1080/1744666x.2024.2366301] [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: 03/12/2024] [Accepted: 06/05/2024] [Indexed: 06/09/2024]
Abstract
INTRODUCTION Despite the fact incidence and mortality vary widely among regions, sepsis remains a major cause of morbidity and cost worldwide. The importance of the endothelial barrier in sepsis and infectious diseases is increasingly recognized; however, the underlying pathophysiology of the endothelial barrier in sepsis remains poorly understood. AREAS COVERED Here we review the advances in basic and clinical research for relevant papers in PubMed database. We attempt to provide an updated overview of immunological alterations in endothelial dysfunction, discussing the central role of endothelial barrier involved in sepsis to provide new predictive and therapeutic paradigm for sepsis. EXPERT OPINION Given its physiological and immunological functions in infectious diseases, the endothelial barrier has been dramatically altered in sepsis, suggesting that endothelial dysfunction may play a critical role in the pathogenesis of sepsis. Although many reliable biomarkers have been investigated to monitor endothelial activation and injury in an attempt to find diagnostic and therapeutic tools, there are no specific therapies to treat sepsis due to its complex pathophysiology. Since sepsis is initiated by both hyperinflammation and immunoparalysis occurring simultaneously, a 'one-treatment-fits-all' strategy for sepsis-induced immune injury and immunoparalysis is bound to fail, and an individualized 'precision medicine' approach is required.
Collapse
Affiliation(s)
- Jun Feng
- Department of Emergency Medicine, Tongji Hospital,Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lina Liu
- Department of Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junya Liu
- Department of Emergency Medicine, Tongji Hospital,Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junshuai Wang
- Department of Emergency Medicine, Tongji Hospital,Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
2
|
Zhuang W, Mitrou NGA, Kulak S, Cupples WA, Braam B. Modulation of the expression of connexins 37, 40, and 43 in endothelial cells in a culture. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 4:1199198. [PMID: 38558785 PMCID: PMC10978589 DOI: 10.3389/fnetp.2024.1199198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 02/28/2024] [Indexed: 04/04/2024]
Abstract
Connexin (Cx) 37, 40, and 43 are implicated in vascular function, specifically in the electrical coupling of endothelial cells and vascular smooth-muscle cells. In the present study, we investigated whether factors implicated in vascular dysfunction can modulate the gene expression of Cx37, Cx40, and Cx43 and whether this is associated with changes in endothelial layer barrier function in human microvascular endothelial cells (HMEC-1). First, HMEC-1 were subjected to stimuli for 4 and 8 h. We tested their responses to DETA-NONOate, H2O2, high glucose, and angiotensin II, none of which relevantly affected the transcription of the connexin genes. Next, we tested inflammatory factors IL-6, interferon gamma (IFNγ), and TNFα. IFNγ (10 ng/mL) consistently induced Cx40 expression at 4 and 8 h to 10-20-fold when corrected for the control. TNFα and IL-6 resulted in small but significant depressions of Cx37 expression at 4 h. Two JAK inhibitors, epigallocatechin-3-gallate (EGCG) (100-250 μM) and AG490 (100-250 μM), dose-dependently inhibited the induction of Cx40 expression by IFNγ. Subsequently, HMEC-1 were subjected to 10 ng/mL IFNγ for 60 h, and intercellular and transcellular impedance was monitored by electric cell-substrate impedance sensing (ECIS). In response to IFNγ, junctional-barrier impedance increased more than cellular-barrier impedance; this was prevented by AG490 (5 μM). In conclusion, IFNγ can strongly induce Cx40 expression and modify the barrier properties of the endothelial cell membrane through the JAK/STAT pathway. Moreover, the Cx37, Cx40, and Cx43 expression in endothelial cells is stable and, apart from IFNγ, not affected by a number of factors implicated in endothelial dysfunction and vascular diseases.
Collapse
Affiliation(s)
- Wenqing Zhuang
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Steve Kulak
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Branko Braam
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
3
|
Kowalewska PM, Milkovich SL, Goldman D, Sandow SL, Ellis CG, Welsh DG. Capillary oxygen regulates demand-supply coupling by triggering connexin40-mediated conduction: Rethinking the metabolic hypothesis. Proc Natl Acad Sci U S A 2024; 121:e2303119121. [PMID: 38349880 PMCID: PMC10895355 DOI: 10.1073/pnas.2303119121] [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: 02/26/2023] [Accepted: 12/21/2023] [Indexed: 02/15/2024] Open
Abstract
Coupling red blood cell (RBC) supply to O2 demand is an intricate process requiring O2 sensing, generation of a stimulus, and signal transduction that alters upstream arteriolar tone. Although actively debated, this process has been theorized to be induced by hypoxia and to involve activation of endothelial inwardly rectifying K+ channels (KIR) 2.1 by elevated extracellular K+ to trigger conducted hyperpolarization via connexin40 (Cx40) gap junctions to upstream resistors. This concept was tested in resting healthy skeletal muscle of Cx40-/- and endothelial KIR2.1-/- mice using state-of-the-art live animal imaging where the local tissue O2 environment was manipulated using a custom gas chamber. Second-by-second capillary RBC flow responses were recorded as O2 was altered. A stepwise drop in PO2 at the muscle surface increased RBC supply in capillaries of control animals while elevated O2 elicited the opposite response; capillaries were confirmed to express Cx40. The RBC flow responses were rapid and tightly coupled to O2; computer simulations did not support hypoxia as a driving factor. In contrast, RBC flow responses were significantly diminished in Cx40-/- mice. Endothelial KIR2.1-/- mice, on the other hand, reacted normally to O2 changes, even when the O2 challenge was targeted to a smaller area of tissue with fewer capillaries. Conclusively, microvascular O2 responses depend on coordinated electrical signaling via Cx40 gap junctions, and endothelial KIR2.1 channels do not initiate the event. These findings reconceptualize the paradigm of blood flow regulation in skeletal muscle and how O2 triggers this process in capillaries independent of extracellular K+.
Collapse
Affiliation(s)
- Paulina M. Kowalewska
- Robarts Research Institute, University of Western Ontario, London, ONN6A 5B7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ONN6A 5B7, Canada
| | | | - Daniel Goldman
- Department of Medical Biophysics, University of Western Ontario, London, ONN6A 5B7, Canada
| | - Shaun L. Sandow
- School of Health, University of the Sunshine Coast, Maroochydore, QLD4556, Australia
- School of Clinical Medicine, University of Queensland, St. Lucia, QLD4072, Australia
| | - Christopher G. Ellis
- Robarts Research Institute, University of Western Ontario, London, ONN6A 5B7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ONN6A 5B7, Canada
| | - Donald G. Welsh
- Robarts Research Institute, University of Western Ontario, London, ONN6A 5B7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ONN6A 5B7, Canada
| |
Collapse
|
4
|
Bkaily G, Jacques D. Morphological and Functional Remodeling of Vascular Endothelium in Cardiovascular Diseases. Int J Mol Sci 2023; 24:ijms24031998. [PMID: 36768314 PMCID: PMC9916505 DOI: 10.3390/ijms24031998] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/21/2023] Open
Abstract
The vascular endothelium plays a vital role during embryogenesis and aging and is a cell monolayer that lines the blood vessels. The immune system recognizes the endothelium as its own. Therefore, an abnormality of the endothelium exposes the tissues to the immune system and provokes inflammation and vascular diseases such as atherosclerosis. Its secretory role allows it to release vasoconstrictors and vasorelaxants as well as cardio-modulatory factors that maintain the proper functioning of the circulatory system. The sealing of the monolayer provided by adhesion molecules plays an important role in cardiovascular physiology and pathology.
Collapse
|
5
|
Roy TK, Secomb TW. Functional implications of microvascular heterogeneity for oxygen uptake and utilization. Physiol Rep 2022; 10:e15303. [PMID: 35581743 PMCID: PMC9114652 DOI: 10.14814/phy2.15303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023] Open
Abstract
In the vascular system, an extensive network structure provides convective and diffusive transport of oxygen to tissue. In the microcirculation, parameters describing network structure, blood flow, and oxygen transport are highly heterogeneous. This heterogeneity can strongly affect oxygen supply and organ function, including reduced oxygen uptake in the lung and decreased oxygen delivery to tissue. The causes of heterogeneity can be classified as extrinsic or intrinsic. Extrinsic heterogeneity refers to variations in oxygen demand in the systemic circulation or oxygen supply in the lungs. Intrinsic heterogeneity refers to structural heterogeneity due to stochastic growth of blood vessels and variability in flow pathways due to geometric constraints, and resulting variations in blood flow and hematocrit. Mechanisms have evolved to compensate for heterogeneity and thereby improve oxygen uptake in the lung and delivery to tissue. These mechanisms, which involve long-term structural adaptation and short-term flow regulation, depend on upstream responses conducted along vessel walls, and work to redistribute flow and maintain blood and tissue oxygenation. Mathematically, the variance of a functional quantity such as oxygen delivery that depends on two or more heterogeneous variables can be reduced if one of the underlying variables is controlled by an appropriate compensatory mechanism. Ineffective regulatory mechanisms can result in poor oxygen delivery even in the presence of adequate overall tissue perfusion. Restoration of endothelial function, and specifically conducted responses, should be considered when addressing tissue hypoxemia and organ failure in clinical settings.
Collapse
Affiliation(s)
- Tuhin K. Roy
- Department of AnesthesiologyMayo ClinicRochesterMinnesotaUSA
| | | |
Collapse
|
6
|
Spectroscopy detects skeletal muscle microvascular dysfunction during onset of sepsis in a rat fecal peritonitis model. Sci Rep 2022; 12:6339. [PMID: 35428849 PMCID: PMC9012880 DOI: 10.1038/s41598-022-10208-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 03/15/2022] [Indexed: 01/20/2023] Open
Abstract
Sepsis is a dysregulated host inflammatory response to infection potentially leading to life-threatening organ dysfunction. The objectives of this study were to determine whether early microvascular dysfunction (MVD) in skeletal muscle can be detected as dynamic changes in microvascular hemoglobin (MVHb) levels using spectroscopy and whether MVD precedes organ histopathology in septic peritonitis. Skeletal muscle of male Sprague-Dawley rats was prepared for intravital microscopy. After intraperitoneal injection of fecal slurry or saline, microscopy and spectroscopy recordings were taken for 6 h. Capillary red blood cell (RBC) dynamics and SO2 were quantified from digitized microscopy frames and MVHb levels were derived from spectroscopy data. Capillary RBC dynamics were significantly decreased by 4 h after peritoneal infection and preceded macrohemodynamic changes. At the same time, low-frequency oscillations in MVHb levels exhibited a significant increase in Power in parts of the muscle and resembled oscillations in RBC dynamics and SO2. After completion of microscopy, tissues were collected. Histopathological alterations were not observed in livers, kidneys, brains, or muscles 6 h after induction of peritonitis. The findings of this study show that, in our rat model of sepsis, MVD occurs before detectable organ histopathology and includes ~ 30-s oscillations in MVHb. Our work highlights MVHb oscillations as one of the indicators of MVD onset and provides a foundation for the use of non-invasive spectroscopy to continuously monitor MVD in septic patients.
Collapse
|
7
|
Horn T, Ludwig M, Eickmeier O, Neerinex AH, Maitland-van der Zee AH, Smaczny C, Wagner TOF, Schubert R, Zielen S, Majoor C, Bos LD, Schmitt-Grohé S. Impact of a Gap Junction Protein Alpha 4 Variant on Clinical Disease Phenotype in F508del Homozygous Patients With Cystic Fibrosis. Front Genet 2020; 11:570403. [PMID: 33193670 PMCID: PMC7655539 DOI: 10.3389/fgene.2020.570403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 10/02/2020] [Indexed: 11/18/2022] Open
Abstract
Background Lung disease phenotype varies widely even in the F508del (homozygous) genotype. Leukocyte-driven inflammation is important for pulmonary disease pathogenesis in cystic fibrosis (CF). Blood cytokines correlate negatively with pulmonary function in F508del homozygous patients, and gap junction proteins (GJA) might be related to the influx of blood cells into the lung and influence disease course. We aimed to assess the relationship between GJA1/GJA4 genotypes and the clinical disease phenotype. Methods One-hundred-and-sixteen homozygous F508del patients (mean age 27 years, m/f 66/50) were recruited from the CF centers of Bonn, Frankfurt, and Amsterdam. Sequence analysis was performed for GJA1 and GJA4. The clinical disease course was assessed over 3 years using pulmonary function tests, body mass index, Pseudomonas aeruginosa colonization, diabetes mellitus, survival to end-stage lung disease, blood and sputum inflammatory markers. Results Sequence analysis revealed one clinically relevant single nucleotide polymorphism. In this GJA4 variant (rs41266431), homozygous G variant carriers (n = 84/116; 72.4%) had poorer pulmonary function (FVC% pred: mean 78/86, p < 0.040) and survival to end-stage lung disease was lower (p < 0.029). The frequency of P. aeruginosa colonization was not influenced by the genotype, but in those chronically colonized, those with the G/G genotype had reduced pulmonary function (FVC% pred: mean 67/80, p < 0.049). Serum interleukin-8 (median: 12.4/6.7 pg/ml, p < 0.052) and sputum leukocytes (2305/437.5 pg/ml, p < 0.025) were higher for the G/G genotype. Conclusions In carriers of the A allele (27.6%) the GJA4 variant is associated with significantly better protection against end-stage lung disease and superior pulmonary function test results in F508del homozygous patients. This SNP has the potential of a modifier gene for phenotyping severity of CF lung disease, in addition to the CFTR genotype. Clinical Trial Registration The study was registered with ClinicalTrials.gov, number NCT04242420, retrospectively on January 24th, 2020.
Collapse
Affiliation(s)
- Tabea Horn
- Abt. Allgemeine Pädiatrie, Zentrum für Kinderheilkunde des Universitätsklinikums Bonn, Bonn, Germany
| | - Michael Ludwig
- Institut für Klinische Chemie und Klinische Pharmakologie des Universitätsklinikums Bonn, Bonn, Germany
| | - Olaf Eickmeier
- Department for Children and Adolescents, Division of Allergology, Pulmonology and Cystic Fibrosis, Goethe University, Frankfurt, Germany
| | - Anne H Neerinex
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Anke H Maitland-van der Zee
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Respiratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Christina Smaczny
- Christiane-Herzog CF-Ambulanz, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Thomas O F Wagner
- Christiane-Herzog CF-Ambulanz, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Ralf Schubert
- Department for Children and Adolescents, Division of Allergology, Pulmonology and Cystic Fibrosis, Goethe University, Frankfurt, Germany
| | - Stefan Zielen
- Department for Children and Adolescents, Division of Allergology, Pulmonology and Cystic Fibrosis, Goethe University, Frankfurt, Germany
| | - Christof Majoor
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Lieuwe D Bos
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Department of Intensive Care Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Sabina Schmitt-Grohé
- Abt. Allgemeine Pädiatrie, Zentrum für Kinderheilkunde des Universitätsklinikums Bonn, Bonn, Germany.,Department for Children and Adolescents, Division of Allergology, Pulmonology and Cystic Fibrosis, Goethe University, Frankfurt, Germany
| |
Collapse
|
8
|
COVID-19 and Microvascular Disease: Pathophysiology of SARS-CoV-2 Infection With Focus on the Renin-Angiotensin System. Heart Lung Circ 2020; 29:1596-1602. [PMID: 32972810 PMCID: PMC7467122 DOI: 10.1016/j.hlc.2020.08.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/26/2020] [Accepted: 08/14/2020] [Indexed: 02/08/2023]
Abstract
The recently described severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people, with thousands of fatalities. It has prompted global efforts in research, with focus on the pathophysiology of coronavirus disease-19 (COVID-19), and a rapid surge of publications. COVID-19 has been associated with a myriad of clinical manifestations, including the lungs, heart, kidneys, central nervous system, gastrointestinal system, skin, and blood coagulation abnormalities. The endothelium plays a key role in organ dysfunction associated with severe infection, and current data suggest that it is also involved in SARS-CoV-2-induced sepsis. This critical review aimed to address a possible unifying mechanism underlying the diverse complications of COVID-19: microvascular dysfunction, with emphasis on the renin-angiotensin system. In addition, research perspectives are suggested in order to expand understanding of the pathophysiology of the infection.
Collapse
|
9
|
Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
Collapse
Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| |
Collapse
|
10
|
Maibier M, Bintig W, Goede A, Höpfner M, Kuebler WM, Secomb TW, Nitzsche B, Pries AR. Gap junctions regulate vessel diameter in chick chorioallantoic membrane vasculature by both tone-dependent and structural mechanisms. Microcirculation 2019; 27:e12590. [PMID: 31520425 DOI: 10.1111/micc.12590] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/21/2019] [Accepted: 09/09/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVE In this study, we examined the impact of gap junction blockade on chick chorioallantoic membrane microvessels. METHODS Expression of Cx37, Cx40/42, and Cx43 in chick chorioallantoic membrane tissue was studied by PCR, Western blot, and confocal immunofluorescence microscopy. Vessel diameter changes occurring under gap junction blockade with carbenoxolone (175 µmol/L), palmitoleic acid (100 µmol/L), 43 GAP27 (1 mmol/L) were analyzed by intravital microscopy. To analyze vascular tone, chick chorioallantoic membrane vessels were exposed to a vasodilator cocktail consisting of acetylcholine (10 μmol/L), adenosine (100 μmol/L), papaverine (200 μmol/L), and sodium nitroprusside (10 μmol/L). RESULTS In chick chorioallantoic membrane lysates, Western blot analysis revealed the expression of Cx40 and Cx43. Immunofluorescence in intact chick chorioallantoic membrane vasculature showed only Cx43, limited to arterial vessel walls. Upon gap junction blockade (3 hours) arterial and venous diameters decreased to 0.50 ± 0.03 and 0.36 ± 0.06 (carbenoxolone), 0.72 ± 0.08 and 0.63 ± 0.15 (palmitoleic acid) and 0.77 ± 0.004 and 0.58 ± 0.05 (GAP27), relative to initial values. Initially, diameter decrease was dominated by increasing vascular tone. After 6 hours, however, vessel tone was reduced, suggesting structural network remodeling. CONCLUSIONS Our findings suggest a major role for connexins in mediating acute and chronic diameter changes in developing vascular networks.
Collapse
Affiliation(s)
- Martin Maibier
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Willem Bintig
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Biochemistry & Neuro Cure Cluster of Excellence, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Andrean Goede
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Michael Höpfner
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Wolfgang M Kuebler
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
- Departments of Surgery and Physiology, University of Toronto, Toronto, ON, Canada
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Bianca Nitzsche
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Axel R Pries
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- German Heart Center Berlin, Berlin, Germany
| |
Collapse
|
11
|
Javed S, Mitchell K, Sidsworth D, Sellers SL, Reutens-Hernandez J, Massicotte HB, Egger KN, Lee CH, Payne GW. Inonotus obliquus attenuates histamine-induced microvascular inflammation. PLoS One 2019; 14:e0220776. [PMID: 31437163 PMCID: PMC6706056 DOI: 10.1371/journal.pone.0220776] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 07/23/2019] [Indexed: 01/14/2023] Open
Abstract
Cell-to-cell communication is a key element of microvascular blood flow control, including rapidly carrying signals through the vascular endothelium in response to local stimuli. This cell-to-cell communication is negatively impacted during inflammation through the disruption of junctional integrity. Such disruption is associated with promoting the onset of cardiovascular diseases as a result of altered microvascular blood flow regulation. Therefore, understanding the mechanisms how inflammation drives microvascular dysfunction and compounds that mitigate such inflammation and dysfunction are of great interest for development. As such we aimed to investigate extracts of mushrooms as potential novel compounds. Using intravital microscopy, the medicinal mushroom, Inonotus obliquus was observed, to attenuate histamine-induced inflammation conducted vasodilation in second-order arterioles in the gluteus maximus muscle of C57BL/6 mice. Mast cell activation by C48/80 similarly disrupted endothelial junctions and conducted vasodilation but only histamine was blocked by the histamine antagonist, pyrilamine not C48/80 suggesting the importance of mast cell activation. Data presented here supports that histamine induced inflammation is a major disruptor of junctional integrity, and highlights the important anti-inflammatory properties of Inonotus obliquus focusing future assessment of mast cells as putative target for Inonotus obliquus.
Collapse
Affiliation(s)
- Sumreen Javed
- Biochemistry and Molecular Biology Program, University of Northern British Columbia, Prince George, Canada
| | - Kevin Mitchell
- Northern Medical Program, University of Northern British Columbia, Prince George, Canada
| | - Danielle Sidsworth
- Northern Medical Program, University of Northern British Columbia, Prince George, Canada
| | - Stephanie L. Sellers
- Centre for Heart Lung Innovation & Department of Radiology, University of British Columba & St. Paul’s Hospital, Vancouver, Canada
| | - Jennifer Reutens-Hernandez
- Biochemistry and Molecular Biology Program, University of Northern British Columbia, Prince George, Canada
| | - Hugues B. Massicotte
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, Canada
| | - Keith N. Egger
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, Canada
| | - Chow H. Lee
- Biochemistry and Molecular Biology Program, University of Northern British Columbia, Prince George, Canada
| | - Geoffrey W. Payne
- Northern Medical Program, University of Northern British Columbia, Prince George, Canada
- * E-mail:
| |
Collapse
|
12
|
Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
Collapse
Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
| |
Collapse
|
13
|
Simmons S, Erfinanda L, Bartz C, Kuebler WM. Novel mechanisms regulating endothelial barrier function in the pulmonary microcirculation. J Physiol 2018; 597:997-1021. [PMID: 30015354 DOI: 10.1113/jp276245] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/25/2018] [Indexed: 12/11/2022] Open
Abstract
The pulmonary epithelial and vascular endothelial cell layers provide two sequential physical and immunological barriers that together form a semi-permeable interface and prevent alveolar and interstitial oedema formation. In this review, we focus specifically on the continuous endothelium of the pulmonary microvascular bed that warrants strict control of the exchange of gases, fluid, solutes and circulating cells between the plasma and the interstitial space. The present review provides an overview of emerging molecular mechanisms that permit constant transcellular exchange between the vascular and interstitial compartment, and cause, prevent or reverse lung endothelial barrier failure under experimental conditions, yet with a clinical perspective. Based on recent findings and at times seemingly conflicting results we discuss emerging paradigms of permeability regulation by altered ion transport as well as shifts in the homeostasis of sphingolipids, angiopoietins and prostaglandins.
Collapse
Affiliation(s)
- Szandor Simmons
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lasti Erfinanda
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Christoph Bartz
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Departments of Surgery and Physiology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
14
|
Zhou HS, Li M, Sui BD, Wei L, Hou R, Chen WS, Li Q, Bi SH, Zhang JZ, Yi DH. Lipopolysaccharide impairs permeability of pulmonary microvascular endothelial cells via Connexin40. Microvasc Res 2018; 115:58-67. [PMID: 28870649 DOI: 10.1016/j.mvr.2017.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/25/2017] [Accepted: 08/30/2017] [Indexed: 12/27/2022]
Abstract
The endotoxin lipopolysaccharide (LPS)-induced pulmonary endothelial barrier disruption is a key pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the molecular mechanisms underlying LPS-impaired permeability of pulmonary microvascular endothelial cells (PMVECs) are not fully understood. Gap junctions, particularly Connexin40 (Cx40), are necessary for the maintenance of normal vascular function. In this study, we for the first time investigated the role of Cx40 in LPS-impaired permeability of PMVECs and provided potential therapeutic approaches based on mechanistic findings of Cx40 regulation by LPS stimuli. Rat PMVECs were isolated, cultured and identified with cell morphology, specific markers, ultrastructural characteristics and functional tests. Western blot analysis demonstrated that Cx40 is the major connexin highly expressed in PMVECs. Furthermore, by inhibiting Cx40 in a time-dependent manner, LPS impaired gap junction function and induced permeability injury of PMVECs. The key role of Cx40 decline in mediating detrimental effects of LPS was further confirmed in rescue experiments through Cx40 overexpression. Mechanistically, LPS stress on PMVECs inhibited the protein kinase C (PKC) pathway, which may synergize with the inflammatory nuclear factor kappaB (NFκB) signaling activation in suppressing Cx40 expression level and phosphorylation. Moreover, through pharmacological PKC activation or NFκB inhibition, Cx40 activity in PMVECs could be restored, leading to maintained barrier function under LPS stress. Our findings uncover a previously unrecognized role of Cx40 and its regulatory mechanisms in impaired endothelial integrity under endotoxin and inflammation, shedding light on intervention approaches to improve pulmonary endothelial barrier function in ALI and ARDS.
Collapse
Affiliation(s)
- Hua-Song Zhou
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Meng Li
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Bing-Dong Sui
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA 19104, USA
| | - Lei Wei
- Xi'an Satellite Control Centre Clinic, Xi'an, Shaanxi 710043, China
| | - Rui Hou
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Wen-Sheng Chen
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Qiang Li
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Sheng-Hui Bi
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jin-Zhou Zhang
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| | - Ding-Hua Yi
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| |
Collapse
|
15
|
Zhang X, Wang B, Xiao Y, Wang C, He L. Targetable, two-photon fluorescent probes for local nitric oxide capture in the plasma membranes of live cells and brain tissues. Analyst 2018; 143:4180-4188. [DOI: 10.1039/c8an00905h] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A plasma membrane-targetable two-photon fluorescent probe for capturing nitric oxide in cells and brain tissues.
Collapse
Affiliation(s)
- Xinfu Zhang
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- China
| | - Benlei Wang
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- China
| | - Yi Xiao
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- China
| | - Chao Wang
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- China
| | - Ling He
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- China
| |
Collapse
|
16
|
The Role of Gap Junction-Mediated Endothelial Cell-Cell Interaction in the Crosstalk between Inflammation and Blood Coagulation. Int J Mol Sci 2017; 18:ijms18112254. [PMID: 29077057 PMCID: PMC5713224 DOI: 10.3390/ijms18112254] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/21/2017] [Accepted: 10/24/2017] [Indexed: 12/29/2022] Open
Abstract
Endothelial cells (ECs) play a pivotal role in the crosstalk between blood coagulation and inflammation. Endothelial cellular dysfunction underlies the development of vascular inflammatory diseases. Recent studies have revealed that aberrant gap junctions (GJs) and connexin (Cx) hemichannels participate in the progression of cardiovascular diseases such as cardiac infarction, hypertension and atherosclerosis. ECs can communicate with adjacent ECs, vascular smooth muscle cells, leukocytes and platelets via GJs and Cx channels. ECs dynamically regulate the expression of numerous Cxs, as well as GJ functionality, in the context of inflammation. Alterations to either result in various side effects across a wide range of vascular functions. Here, we review the roles of endothelial GJs and Cx channels in vascular inflammation, blood coagulation and leukocyte adhesion. In addition, we discuss the relevant molecular mechanisms that endothelial GJs and Cx channels regulate, both the endothelial functions and mechanical properties of ECs. A better understanding of these processes promises the possibility of pharmacological treatments for vascular pathogenesis.
Collapse
|
17
|
Tyml K. Vitamin C and Microvascular Dysfunction in Systemic Inflammation. Antioxidants (Basel) 2017; 6:antiox6030049. [PMID: 28661424 PMCID: PMC5618077 DOI: 10.3390/antiox6030049] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 02/07/2023] Open
Abstract
Sepsis, life-threatening organ dysfunction caused by a dysfunctional host response to infection, is associated with high mortality. A promising strategy to improve the outcome is to inject patients intravenously with ascorbate (vitamin C). In animal models of sepsis, this injection improves survival and, among others, the microvascular function. This review examines our recent work addressing ascorbate's ability to inhibit arteriolar dysfunction and capillary plugging in sepsis. Arteriolar dysfunction includes impaired vasoconstriction/dilation (previously reviewed) and impaired conduction of vasoconstriction/dilation along the arteriole. We showed that ascorbate injected into septic mice prevents impaired conducted vasoconstriction by inhibiting neuronal nitric oxide synthase-derived NO, leading to restored inter-endothelial electrical coupling through connexin 37-containing gap junctions. Hypoxia/reoxygenation (confounding factor in sepsis) also impairs electrical coupling by protein kinase A (PKA)-dependent connexin 40 dephosphorylation; ascorbate restores PKA activation required for this coupling. Both effects of ascorbate could explain its ability to protect against hypotension in sepsis. Capillary plugging in sepsis involves P-selectin mediated platelet-endothelial adhesion and microthrombi formation. Early injection of ascorbate prevents capillary plugging by inhibiting platelet-endothelial adhesion and endothelial surface P-selectin expression. Ascorbate also prevents thrombin-induced platelet aggregation and platelet surface P-selectin expression, thus preventing microthrombi formation. Delayed ascorbate injection reverses capillary plugging and platelet-endothelial adhesion; it also attenuates sepsis-induced drop in platelet count in systemic blood. Thrombin-induced release of plasminogen-activator-inhibitor-1 from platelets (anti-fibrinolytic event in sepsis) is inhibited by ascorbate pH-dependently. Thus, under acidotic conditions in sepsis, ascorbate promotes dissolving of microthrombi in capillaries. We propose that protected/restored arteriolar conduction and capillary bed perfusion by ascorbate contributes to reduced organ injury and improved survival in sepsis.
Collapse
Affiliation(s)
- Karel Tyml
- Centre for Critical Illness Research, Lawson Health Research Institute, London, ON N6A 5W9, Canada.
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada.
| |
Collapse
|
18
|
Yu L, Yang H, Xiang Y, Guo X, Liu Z, Guo R. Association between Cx37 rs1764390 polymorphism and susceptibility to sepsis in Chinese population. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2017; 48:64-70. [PMID: 27939333 DOI: 10.1016/j.meegid.2016.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/02/2016] [Accepted: 12/03/2016] [Indexed: 10/20/2022]
Abstract
In this study, we aimed to explore the possible relationship between a functional single-nucleotide polymorphism (SNP) rs1764390 in Cx37 and sepsis. We also investigated the difference of Cx37 expression in septic patients and healthy controls. A case-control study was performed in 215 septic patients and in 260 healthy controls. Genotyping of the rs1764390 polymorphism was performed by sequencing method. The expression of Cx37 in peripheral blood mononuclear cells (PBMCs) from septic patients and healthy controls was determined by real-time PCR and western-blotting. Plasma levels of NO, IL-6, and C reactive protein (CRP) were also detected in septic patients and healthy controls. The frequencies of GG genotype and the rs1764390 G allele were significantly higher in septic patients than in healthy controls. We also observed a decreased expression of Cx37 protein in septic patients compared to the healthy controls accompanied by increased plasma levels of NO, IL-6 and CRP. Furthermore, the carriers of rs1764390 G allele showed higher levels of NO, IL-6 and CRP in septic patients. The rs1764390 G allele is associated with increased susceptibility to sepsis, which may be involved in the process of sepsis via mediating the plasma levels of NO, IL-6 and CRP.
Collapse
Affiliation(s)
- Lijin Yu
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Heng Yang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yuanyuan Xiang
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xin Guo
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zuoliang Liu
- Department of ICU, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ren Guo
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China.
| |
Collapse
|
19
|
Siddiqui M, Swarbreck S, Shao Q, Secor D, Peng T, Laird DW, Tyml K. Critical Role of Cx40 in Reduced Endothelial Electrical Coupling by Lipopolysaccharide and Hypoxia-Reoxygenation. J Vasc Res 2016; 52:396-403. [PMID: 27194161 DOI: 10.1159/000445772] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/20/2016] [Indexed: 12/16/2023] Open
Abstract
BACKGROUND We discovered that lipopolysaccharide (LPS, an initiating factor in sepsis) and hypoxia-reoxygenation (H/R, a confounding factor) reduce electrical coupling between microvascular endothelial cells from wild-type (WT) but not Cx40-/- mice. Because Cx40 knockout could result in nonspecific effects, this discovery may not establish the causal relationship between Cx40 and reduced coupling. Using the same cell culture model, we aimed to address this uncertainty by using the rescue-of-function approach. METHODS/RESULTS Electrical coupling between endothelial cells (hind-limb muscle origin) was determined by electrophysiology. LPS, H/R and concurrent LPS + H/R reduced coupling between WT but not Cx40-/- cells. The defect in Cx40-/- cells was rescued by ectopic expression of Cx40, after infecting the cells with adenovirus encoding Cx40. Cx40-/- cells were also engineered to express mutant Cx40 that lacked the carboxyl terminal domain beginning at residue 236 (Cx40x0394;237-358) or 344 (Cx40x0394;345-358). No response to inflammatory stimuli was observed in cells expressing either of these 2 mutants. CONCLUSION Our data establish the causal relationship between Cx40 and reduced coupling and suggest that the 345-358 amino acid motif of the Cx40 carboxyl terminal is required for reduced coupling. Cx40 may participate in compromised conducted response in the microvasculature during sepsis.
Collapse
Affiliation(s)
- Mohammad Siddiqui
- Lawson Health Research Institute, Critical Illness Research, London, Ont., Canada
| | | | | | | | | | | | | |
Collapse
|
20
|
Oncogenic extracellular HSP70 disrupts the gap-junctional coupling between capillary cells. Oncotarget 2016; 6:10267-83. [PMID: 25868858 PMCID: PMC4496354 DOI: 10.18632/oncotarget.3522] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/17/2015] [Indexed: 12/31/2022] Open
Abstract
High levels of circulating heat shock protein 70 (HSP70) are detected in many cancers. In order to explore the effects of extracellular HSP70 on human microvascular endothelial cells (HMEC), we initially used gap-FRAP technique. Extracellular human HSP70 (rhHSP70), but not rhHSP27, blocks the gap-junction intercellular communication (GJIC) between HMEC, disrupts the structural integrity of HMEC junction plaques, and decreases connexin43 (Cx43) expression, which correlates with the phosphorylation of Cx43 serine residues. Further exploration of these effects identified a rapid transactivation of the Epidermal Growth Factor Receptor in a Toll-Like Receptor 4-dependent manner, preceding its internalization. In turn, cytosolic Ca2+ oscillations are generated. Both GJIC blockade and Ca2+ mobilization partially depend on ATP release through Cx43 and pannexin (Panx-1) channels, as demonstrated by blocking activity or expression of channels, and inactivating extracellular ATP. By monitoring dye-spreading into adjacent cells, we show that HSP70 released from human monocytes in response to macrophage colony-stimulating factor, prevents the formation of GJIC between monocytes and HMEC. Therapeutic manipulation of this pathway could be of interest in inflammatory and tumor growth.
Collapse
|
21
|
Colbert JF, Schmidt EP. Endothelial and Microcirculatory Function and Dysfunction in Sepsis. Clin Chest Med 2016; 37:263-75. [PMID: 27229643 DOI: 10.1016/j.ccm.2016.01.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The microcirculation is a series of arterioles, capillaries, and venules that performs essential functions of oxygen and nutrient delivery, customized to the unique physiologic needs of the supplied organ. The homeostatic microcirculatory response to infection can become harmful if overactive and/or dysregulated. Pathologic microcirculatory dysfunction can be directly visualized by intravital microscopy or indirectly measured via detection of circulating biomarkers. Although several treatments have been shown to protect the microcirculation during sepsis, they have not improved patient outcomes when applied indiscriminately. Future outcomes-oriented studies are needed to test sepsis therapeutics when personalized to a patient's microcirculatory dysfunction.
Collapse
Affiliation(s)
- James F Colbert
- Division of Infectious Diseases, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Avenue, Aurora, CO 80045, USA
| | - Eric P Schmidt
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, Denver Health Medical Center, University of Colorado School of Medicine, 12700 E. 19th Avenue, Aurora, CO 80045, USA.
| |
Collapse
|
22
|
Scully CG, Mitrou N, Braam B, Cupples WA, Chon KH. Segmentation of renal perfusion signals from laser speckle imaging into clusters with phase synchronized dynamics. IEEE Trans Biomed Eng 2015; 61:1989-97. [PMID: 24956617 DOI: 10.1109/tbme.2014.2311118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Renal perfusion signals contain dynamics arising from the renal autoregulation feedback mechanisms as the contraction and dilation of vessels alter flow patterns. We can capture the time-varying dynamics at points across the renal surface using laser speckle imaging. We segment an imaged area of the renal cortex into clusters with phase synchronized dynamics. Our approach first uses phase coherence with a surrogate data derived threshold to identify synchronized pixel pairs. Non-negative matrix factorization is then applied to segment phase coherence estimates into phase synchronized regions. The method is applied to laser speckle imaging of the renal cortex of anaesthetized rats to identify regions on the renal surface with phase synchronized myogenic activity. In three out of six animals imaged after bolus infusion of N(ω)-nitro-l-arginine methyl ester (NAM), the renal surfaces are segmented into clusters with high phase coherence. No more than two clusters were identified during control period for any animal. In the remaining three animals, a strong myogenic signal could not be detected in surface perfusion during control or NAM. This method can be used to identify synchronization in renal autoregulation dynamics across the renal surface.
Collapse
|
23
|
Winterhager E, Kidder GM. Gap junction connexins in female reproductive organs: implications for women's reproductive health. Hum Reprod Update 2015; 21:340-52. [PMID: 25667189 DOI: 10.1093/humupd/dmv007] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/20/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Connexins comprise a family of ~20 proteins that form intercellular membrane channels (gap junction channels) providing a direct route for metabolites and signalling molecules to pass between cells. This review provides a critical analysis of the evidence for essential roles of individual connexins in female reproductive function, highlighting implications for women's reproductive health. METHODS No systematic review has been carried out. Published literature from the past 35 years was surveyed for research related to connexin involvement in development and function of the female reproductive system. Because of the demonstrated utility of genetic manipulation for elucidating connexin functions in various organs, much of the cited information comes from research with genetically modified mice. In some cases, a distinction is drawn between connexin functions clearly related to the formation of gap junction channels and those possibly linked to non-channel roles. RESULTS AND CONCLUSIONS Based on work with mice, several connexins are known to be required for female reproductive functions. Loss of connexin43 (CX43) causes an oocyte deficiency, and follicles lacking or expressing less CX43 in granulosa cells exhibit reduced growth, impairing fertility. CX43 is also expressed in human cumulus cells and, in the context of IVF, has been correlated with pregnancy outcome, suggesting that this connexin may be a determinant of oocyte and embryo quality in women. Loss of CX37, which exclusively connects oocytes with granulosa cells in the mouse, caused oocytes to cease growing without acquiring meiotic competence. Blocking of CX26 channels in the uterine epithelium disrupted implantation whereas loss or reduction of CX43 expression in the uterine stroma impaired decidualization and vascularization in mouse and human. Several connexins are important in placentation and, in the human, CX43 is a key regulator of the fusogenic pathway from the cytotrophoblast to the syncytiotrophoblast, ensuring placental growth. CX40, which characterizes the extravillous trophoblast (EVT), supports proliferation of the proximal EVTs while preventing them from differentiating into the invasive pathway. Furthermore, women with recurrent early pregnancy loss as well as those with endometriosis exhibit reduced levels of CX43 in their decidua. The antimalaria drug mefloquine, which blocks gap junction function, is responsible for increased risk of early pregnancy loss and stillbirth, probably due to inhibition of intercellular communication in the decidua or between trophoblast layers followed by an impairment of placental growth. Gap junctions also play a critical role in regulating uterine blood flow, contributing to the adaptive response to pregnancy. Given that reproductive impairment can result from connexin mutations in mice, it is advised that women suffering from somatic disease symptoms associated with connexin gene mutations be additionally tested for impacts on reproductive function. Better knowledge of these essential connexin functions in human female reproductive organs is important for safeguarding women's reproductive health.
Collapse
Affiliation(s)
- Elke Winterhager
- Institute of Molecular Biology, University of Duisburg-Essen, University Clinics, 45211 Essen, Germany
| | - Gerald M Kidder
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario and Children's Health Research Institute, London, Ontario N6C 2V5, Canada
| |
Collapse
|
24
|
O’Donnell JJ, Birukova AA, Beyer EC, Birukov KG. Gap junction protein connexin43 exacerbates lung vascular permeability. PLoS One 2014; 9:e100931. [PMID: 24967639 PMCID: PMC4072707 DOI: 10.1371/journal.pone.0100931] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/02/2014] [Indexed: 11/20/2022] Open
Abstract
Increased vascular permeability causes pulmonary edema that impairs arterial oxygenation and thus contributes to morbidity and mortality associated with Acute Respiratory Distress Syndrome and sepsis. Although components of intercellular adhesive and tight junctions are critical for maintaining the endothelial barrier, there has been limited study of the roles of gap junctions and their component proteins (connexins). Since connexins can modulate inflammatory signaling in other systems, we hypothesized that connexins may also regulate pulmonary endothelial permeability. The relationships between connexins and the permeability response to inflammatory stimuli were studied in cultured human pulmonary endothelial cells. Prolonged treatment with thrombin, lipopolysaccharide, or pathological cyclic stretch increased levels of mRNA and protein for the major connexin, connexin43 (Cx43). Thrombin and lipopolysaccharide both increased intercellular communication assayed by transfer of microinjected Lucifer yellow. Although thrombin decreased transendothelial resistance in these cells, the response was attenuated by pretreatment with the connexin inhibitor carbenoxolone. Additionally, the decreases of transendothelial resistance produced by either thrombin or lipopolysaccharide were attenuated by reducing Cx43 expression by siRNA knockdown. Both carbenoxolone and Cx43 knockdown also abrogated thrombin-induced phosphorylation of myosin light chain. Taken together, these data suggest that increased lung vascular permeability induced by inflammatory conditions may be amplified via increased expression of Cx43 and intercellular communication among pulmonary endothelial cells.
Collapse
Affiliation(s)
- James J. O’Donnell
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
- Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Anna A. Birukova
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
- Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Eric C. Beyer
- Department of Pediatrics, University of Chicago, Chicago, Illinois, United States of America
| | - Konstantin G. Birukov
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
- Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: *
| |
Collapse
|
25
|
Morel S, Braunersreuther V, Chanson M, Bouis D, Rochemont V, Foglia B, Pelli G, Sutter E, Pinsky DJ, Mach F, Kwak BR. Endothelial Cx40 limits myocardial ischaemia/reperfusion injury in mice. Cardiovasc Res 2014; 102:329-37. [PMID: 24639196 DOI: 10.1093/cvr/cvu063] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
AIMS Gap junctions are indispensable for the function of heart and blood vessels by providing electrical coupling and direct cell-to-cell transfer of small signalling molecules. Gap junction channels between neighbouring cells are composed of 12 connexins (Cx). Changes in Cx43 expression, localization, and channel properties in cardiomyocytes contribute to infarction and reperfusion injury of the heart. It is increasingly recognized that deleterious consequences of ischaemia/reperfusion (IR) are modulated by the inflammatory response and endothelial function. The role of the endothelial connexins, i.e. Cx40 and Cx37, in cardiac IR injury is, however, not known. METHODS AND RESULTS Following 30 min ischaemia and 24 h reperfusion, we found a significant increase in myocardial infarct size in mice with endothelial-specific deletion of Cx40 (Cx40del), but not in Cx37-deficient mice. The cardioprotective effect of endothelial Cx40 was associated with a decrease in neutrophil infiltration. Moreover, beneficial effects of endothelial Cx40 were not observed in isolated Langendorff-perfused hearts, suggesting direct involvement of endothelial-leucocyte interactions in the cardiac injury. Single-dose administration of methotrexate, a CD73 activator, reduced infarct size and neutrophil infiltration into the infarcted myocardium in Cx40del but not in control mice. Similar to Cx40del mice, CD73-deficient mice showed increased sensitivity to cardiac IR injury, which could not be conversed by methotrexate. CONCLUSION Endothelial Cx40, but not Cx37, is implicated in resistance of the heart to IR injury by activation of the CD73 pathway. Thus, the Cx40-CD73 axis may represent an interesting target for controlling reperfusion damage associated with revascularization in coronary disease.
Collapse
Affiliation(s)
- Sandrine Morel
- Department of Pathology and Immunology, University of Geneva Medical School, CMU, Rue Michel-Servet 1, CH-1211 Geneva 4, Switzerland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Cheng YS, Dai DZ, Dai Y. AQP4 KO exacerbating renal dysfunction is mediated by endoplasmic reticulum stress and p66Shc and is attenuated by apocynin and endothelin antagonist CPU0213. Eur J Pharmacol 2013; 721:249-58. [PMID: 24135202 DOI: 10.1016/j.ejphar.2013.09.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 08/31/2013] [Accepted: 09/11/2013] [Indexed: 01/25/2023]
Abstract
Aquaporin 4 (AQP4) is essential in normal kidney. We hypothesized that AQP4 knockout (KO) may exacerbate pro-inflammatory factors in the stress induced renal insufficiency. Mechanisms underlying are likely due to activating renal oxidative stress adaptor p66Shc and endoplasmic reticulum (ER) stress that could be mediated by endothelin (ET)-NADPH oxidase (NOX) pathway. AQP4 KO and wild type (WT) mice were randomly divided into 4 groups: control, isoproterenol (1mg/kg, s.c., 5d), and interventions in the last 3 days with either apocynin (NADPH oxidase inhibitor, 100mg/kg, p.o.) or CPU0213 (a dual endothelin receptor antagonist 200mg/kg, p.o.). In addition, HK2 cells were cultured in 4 groups: control, isoproterenol (10(-6)M), intervened with apocynin (10(-6)M) or CPU0213 (10(-6)M). In AQP4 KO mice elevated creatinine levels were further increased by isoproterenol compared to AQP4 KO alone. In RT-PCR, western blot and immunohistochemical assay p66Shc and PERK were significantly increased in the kidney of AQP4 KO mice, associated with pro-inflammatory factors CX40, CX43, MMP-9 and ETA compared to the WT mice. Expression of AQP4 was escalated in isoproterenol incubated HK2 cells, and the enhanced protein of PERK and p-PERK/PERK, and p66shc in vivo and in vitro were significantly attenuated by either apocynin or CPU0213. In conclusion, AQP4 KO deteriorates renal dysfunction due to exacerbating ER stress and p66Shc in the kidney. Either endothelin antagonism or NADPH oxidase blockade partly relieves renal dysfunction through suppressing abnormal biomarkers by APQ4 KO and isoproterenol in the kidney.
Collapse
Affiliation(s)
- Yu-Si Cheng
- Research Division of Pharmacology, China Pharmaceutical University, Nanjing 210009, China
| | | | | |
Collapse
|
27
|
Endothelial control of vasodilation: integration of myoendothelial microdomain signalling and modulation by epoxyeicosatrienoic acids. Pflugers Arch 2013; 466:389-405. [PMID: 23748495 DOI: 10.1007/s00424-013-1303-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 05/24/2013] [Accepted: 05/26/2013] [Indexed: 12/17/2022]
Abstract
Endothelium-derived epoxyeicosatrienoic acids (EETs) are fatty acid epoxides that play an important role in the control of vascular tone in selected coronary, renal, carotid, cerebral and skeletal muscle arteries. Vasodilation due to endothelium-dependent smooth muscle hyperpolarization (EDH) has been suggested to involve EETs as a transferable endothelium-derived hyperpolarizing factor. However, this activity may also be due to EETs interacting with the components of other primary EDH-mediated vasodilator mechanisms. Indeed, the transfer of hyperpolarization initiated in the endothelium to the adjacent smooth muscle via gap junction connexins occurs separately or synergistically with the release of K(+) ions at discrete myoendothelial microdomain signalling sites. The net effects of such activity are smooth muscle hyperpolarization, closure of voltage-dependent Ca(2+) channels, phospholipase C deactivation and vasodilation. The spatially localized and key components of the microdomain signalling complex are the inositol 1,4,5-trisphosphate receptor-mediated endoplasmic reticulum Ca(2+) store, Ca(2+)-activated K(+) (KCa), transient receptor potential (TRP) and inward-rectifying K(+) channels, gap junctions and the smooth muscle Na(+)/K(+)-ATPase. Of these, TRP channels and connexins are key endothelial effector targets modulated by EETs. In an integrated manner, endogenous EETs enhance extracellular Ca(2+) influx (thereby amplifying and prolonging KCa-mediated endothelial hyperpolarization) and also facilitate the conduction of this hyperpolarization to spatially remote vessel regions. The contribution of EETs and the receptor and channel subtypes involved in EDH-related microdomain signalling, as a candidate for a universal EDH-mediated vasodilator mechanism, vary with vascular bed, species, development and disease and thus represent potentially selective targets for modulating specific artery function.
Collapse
|