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Tang F, Zhao XL, Xu LY, Zhang JN, Ao H, Peng C. Endothelial dysfunction: Pathophysiology and therapeutic targets for sepsis-induced multiple organ dysfunction syndrome. Biomed Pharmacother 2024; 178:117180. [PMID: 39068853 DOI: 10.1016/j.biopha.2024.117180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 07/13/2024] [Accepted: 07/22/2024] [Indexed: 07/30/2024] Open
Abstract
Sepsis and septic shock are critical medical conditions characterized by a systemic inflammatory response to infection, significantly contributing to global mortality rates. The progression to multiple organ dysfunction syndrome (MODS) represents the most severe complication of sepsis and markedly increases clinical mortality. Central to the pathophysiology of sepsis, endothelial cells play a crucial role in regulating microcirculation and maintaining barrier integrity across various organs and tissues. Recent studies have underscored the pivotal role of endothelial function in the development of sepsis-induced MODS. This review aims to provide a comprehensive overview of the pathophysiology of sepsis-induced MODS, with a specific focus on endothelial dysfunction. It also compiles compelling evidence regarding potential small molecules that could attenuate sepsis and subsequent multi-organ damage by modulating endothelial function. Thus, this review serves as an essential resource for clinical practitioners involved in the diagnosing, managing, and providing intensive care for sepsis and associated multi-organ injuries, emphasizing the importance of targeting endothelial cells to enhance outcomes of the patients.
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Affiliation(s)
- Fei Tang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Xiao-Lan Zhao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Li-Yue Xu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Jing-Nan Zhang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Hui Ao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Cheng Peng
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
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Bouraoui A, Louzada RA, Aimeur S, Waeytens J, Wien F, My-Chan Dang P, Bizouarn T, Dupuy C, Baciou L. New insights in the molecular regulation of the NADPH oxidase 2 activity: Negative modulation by Poldip2. Free Radic Biol Med 2023; 199:113-125. [PMID: 36828293 DOI: 10.1016/j.freeradbiomed.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/06/2023] [Accepted: 02/21/2023] [Indexed: 02/24/2023]
Abstract
Poldip2 was shown to be involved in oxidative signaling to ensure certain biological functions. It was proposed that, in VSMC, by interaction with the Nox4-associated membrane protein p22phox, Poldip2 stimulates the level of reactive oxygen species (ROS) production. In vitro, with fractionated membranes from HEK393 cells over-expressing Nox4, we confirmed the up-regulation of NADPH oxidase 4 activity by the recombinant and purified Poldip2. Besides Nox4, the Nox1, Nox2, or Nox3 isoforms are also established partners of the p22phox protein raising the question of their regulation by Poldip2 and of the effect in cells expressing simultaneously different Nox isoforms. In this study, we have addressed this issue by investigating the potential regulatory role of Poldip2 on NADPH oxidase 2, present in phagocyte cells. Unexpectedly, the effect of Poldip2 on phagocyte NADPH oxidase 2 was opposite to that observed on NADPH oxidase 4. Using membranes from circulating resting neutrophils, the ROS production rate of NADPH oxidase 2 was down-regulated by Poldip2 (2.5-fold). The down-regulation effect could not be correlated to the interaction of Poldip2 with p22phox but rather, to the interaction of Poldip2 with the p47phox protein, one of the regulatory proteins of the phagocyte NADPH oxidase. Our results show that the interaction of Poldip2 with p47phox constitutes a novel regulatory mechanism that can negatively modulate the activity of NADPH oxidase 2 by trapping the so-called "adaptor" subunit of the complex. Poldip2 could act as a tunable switch capable of specifically regulating the activities of NADPH oxidases. This selective regulatory role of Poldip2, positive for Nox4 or negative for Nox2 could orchestrate the level and the type of ROS generated by Nox enzymes in the cells.
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Affiliation(s)
- Aicha Bouraoui
- Université Paris-Saclay, Institut de Chimie Physique UMR 8000, CNRS, 91405, Orsay Cedex, France
| | - Ruy Andrade Louzada
- Université Paris Saclay, UMR 9019 CNRS, Gustave Roussy, 94800, Villejuif, France
| | - Sana Aimeur
- Université Paris-Saclay, Institut de Chimie Physique UMR 8000, CNRS, 91405, Orsay Cedex, France
| | - Jehan Waeytens
- Université Paris-Saclay, Institut de Chimie Physique UMR 8000, CNRS, 91405, Orsay Cedex, France; Structure et Fonction des Membranes Biologiques, Université libre de Bruxelles, Bruxelles, Belgium
| | - Frank Wien
- DISCO beamline, Synchrotron SOLEIL, Campus Paris-Saclay, 91192, Gif-sur-Yvette Cedex, France
| | - Pham My-Chan Dang
- INSERM U1149, CNRS ERL8252, Centre de Recherche sur l'Inflammation, Université de Paris, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Site Xavier Bichat, Paris, F-75018, France
| | - Tania Bizouarn
- Université Paris-Saclay, Institut de Chimie Physique UMR 8000, CNRS, 91405, Orsay Cedex, France
| | - Corinne Dupuy
- Université Paris Saclay, UMR 9019 CNRS, Gustave Roussy, 94800, Villejuif, France
| | - Laura Baciou
- Université Paris-Saclay, Institut de Chimie Physique UMR 8000, CNRS, 91405, Orsay Cedex, France.
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Nguyen T, Urrutia-Cabrera D, Wang L, Lees JG, Wang JH, Hung SS, Hewitt AW, Edwards TL, McLenachan S, Chen FK, Lim SY, Luu CD, Guymer R, Wong RC. Knockout of AMD-associated gene POLDIP2 reduces mitochondrial superoxide in human retinal pigment epithelial cells. Aging (Albany NY) 2023; 15:1713-1733. [PMID: 36795578 PMCID: PMC10085620 DOI: 10.18632/aging.204522] [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: 07/16/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023]
Abstract
Genetic and epidemiologic studies have significantly advanced our understanding of the genetic factors contributing to age-related macular degeneration (AMD). In particular, recent expression quantitative trait loci (eQTL) studies have highlighted POLDIP2 as a significant gene that confers risk of developing AMD. However, the role of POLDIP2 in retinal cells such as retinal pigment epithelium (RPE) and how it contributes to AMD pathology are unknown. Here we report the generation of a stable human RPE cell line ARPE-19 with POLDIP2 knockout using CRISPR/Cas, providing an in vitro model to investigate the functions of POLDIP2. We conducted functional studies on the POLDIP2 knockout cell line and showed that it retained normal levels of cell proliferation, cell viability, phagocytosis and autophagy. Also, we performed RNA sequencing to profile the transcriptome of POLDIP2 knockout cells. Our results highlighted significant changes in genes involved in immune response, complement activation, oxidative damage and vascular development. We showed that loss of POLDIP2 caused a reduction in mitochondrial superoxide levels, which is consistent with the upregulation of the mitochondrial superoxide dismutase SOD2. In conclusion, this study demonstrates a novel link between POLDIP2 and SOD2 in ARPE-19, which supports a potential role of POLDIP2 in regulating oxidative stress in AMD pathology.
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Affiliation(s)
- Tu Nguyen
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Daniel Urrutia-Cabrera
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Luozixian Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Jarmon G. Lees
- O’Brien Institute Department, St Vincent’s Institute of Medical Research, Melbourne, Victoria, Australia
- Departments of Surgery and Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Sandy S.C. Hung
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Alex W. Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Menzies Institute for Medical Research, School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Thomas L. Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Sam McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Fred K. Chen
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Shiang Y. Lim
- O’Brien Institute Department, St Vincent’s Institute of Medical Research, Melbourne, Victoria, Australia
- Departments of Surgery and Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Chi D. Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Robyn Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Raymond C.B. Wong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
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Liu K, Gao X, Hu C, Gui Y, Gui S, Ni Q, Tao L, Jiang Z. Capsaicin ameliorates diabetic retinopathy by inhibiting poldip2-induced oxidative stress. Redox Biol 2022; 56:102460. [PMID: 36088760 PMCID: PMC9468458 DOI: 10.1016/j.redox.2022.102460] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 11/11/2022] Open
Abstract
Background Oxidative stress and the resultant hyperpermeability play a vital role in the pathogenesis of diabetic retinopathy (DR). Poldip2 has been implicated in H2O2 production, but the effects of capsaicin on poldip2 have not been reported. Methods Diabetic Sprague-Dawley (SD) rats induced with STZ were treated with capsaicin or AAV9-poldip2-shRNA, and human retinal microvascular endothelial cells (HRMECs) were treated with capsaicin or poldip2 siRNA. Results Current data indicated that the expression of PPARγ, poldip2, Nox4, VCAM-1, HIF-1α, and VEGF increased in rat retinas with DR and in HRMECs treated with high glucose. The production of ROS or H2O2 in the tissues, serum, and cells increased, and the paracellular permeability of cultured HRMECs with high glucose significantly increased. In addition, overt hyperpermeability of retinal microvessels and increased retinal neovascularization in diabetic rats were observed. However, capsaicin treatment inhibited these increases and suppressed the expression of PPARγ by enhancing its phosphorylation and ubiquitination in the retinas of DR rats. Poldip2 knockdown in HRMECs or its silencing in the retina of DR rats concomitantly led to reduced levels of Nox4, VCAM-1, HIF-1α, VEGF, ROS, and H2O2, and the paracellular permeability of HRMECs or the hyperpermeability of retinal microvessels in diabetic rat retinas decreased. Similarly, after PPARγ knockdown in HRMECs, poldip2, Nox4, HIF-1α, VEGF, ROS, and H2O2 decreased, and the monolayer paracellular permeability was reduced accordingly. Conclusion Capsaicin may ameliorate diabetic retinopathy by activating TRPV1 and suppressing the PPARγ-poldip2-Nox4 pathway.
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Dolmatova EV, Forrester SJ, Wang K, Ou Z, Williams HC, Joseph G, Kumar S, Valdivia A, Kowalczyk AP, Qu H, Jo H, Lassègue B, Hernandes MS, Griendling KK. Endothelial Poldip2 regulates sepsis-induced lung injury via Rho pathway activation. Cardiovasc Res 2022; 118:2506-2518. [PMID: 34528082 PMCID: PMC9612795 DOI: 10.1093/cvr/cvab295] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 09/09/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Sepsis-induced lung injury is associated with significant morbidity and mortality. Previously, we showed that heterozygous deletion of polymerase δ-interacting protein 2 (Poldip2) was protective against sepsis-induced lung injury. Since endothelial barrier disruption is thought to be the main mechanism of sepsis-induced lung injury, we sought to determine if the observed protection was specifically due to the effect of reduced endothelial Poldip2. METHODS AND RESULTS Endothelial-specific Poldip2 knock-out mice (EC-/-) and their wild-type littermates (EC+/+) were injected with saline or lipopolysaccharide (18 mg/kg) to model sepsis-induced lung injury. At 18 h post-injection mice, were euthanized and bronchoalveolar lavage (BAL) fluid and lung tissue were collected to assess leucocyte infiltration. Poldip2 EC-/- mice showed reduced lung leucocyte infiltration in BAL (0.21 ± 0.9×106 vs. 1.29 ± 1.8×106 cells/mL) and lung tissue (12.7 ± 1.8 vs. 23 ± 3.7% neutrophils of total number of cells) compared to Poldip2 EC+/+ mice. qPCR analysis of the lung tissue revealed a significantly dampened induction of inflammatory gene expression (TNFα 2.23 ± 0.39 vs. 4.15 ± 0.5-fold, IκBα 4.32 ± 1.53 vs. 8.97 ± 1.59-fold), neutrophil chemoattractant gene expression (CXCL1 68.8 ± 29.6 vs. 147 ± 25.7-fold, CXCL2 65 ± 25.6 vs. 215 ± 27.3-fold) and a marker of endothelial activation (VCAM1 1.25 ± 0.25 vs. 3.8 ± 0.38-fold) in Poldip2 EC-/- compared to Poldip2 EC+/+ lungs. An in vitro model using human pulmonary microvascular endothelial cells was used to assess the effect of Poldip2 knock-down on endothelial activation and permeability. TNFα-induced endothelial permeability and VE-cadherin disruption were significantly reduced with siRNA-mediated knock-down of Poldip2 (5 ± 0.5 vs. 17.5 ± 3-fold for permeability, 1.5 ± 0.4 vs. 10.9 ± 1.3-fold for proportion of disrupted VE-cadherin). Poldip2 knock-down altered expression of Rho-GTPase-related genes, which correlated with reduced RhoA activation by TNFα (0.94 ± 0.05 vs. 1.29 ± 0.01 of relative RhoA activity) accompanied by redistribution of active-RhoA staining to the centre of the cell. CONCLUSION Poldip2 is a potent regulator of endothelial dysfunction during sepsis-induced lung injury, and its endothelium-specific inhibition may provide clinical benefit.
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Affiliation(s)
- Elena V Dolmatova
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Steven J Forrester
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Keke Wang
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Ziwei Ou
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Holly C Williams
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Giji Joseph
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Sandeep Kumar
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, 313 Ferst Dr NW, Atlanta, GA 30332
| | - Alejandra Valdivia
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Andrew P Kowalczyk
- Departments of Dermatology and Cellular and Molecular Physiology, Penn State College of Medicine, 700 HMC Cres Rd, Hershey, PA 17033
| | - Hongyan Qu
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Hanjoong Jo
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, 313 Ferst Dr NW, Atlanta, GA 30332
| | - Bernard Lassègue
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Marina S Hernandes
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
| | - Kathy K Griendling
- Department of Medicine, Division of Cardiology, Emory University, 101 Woodruff Circle, WMB 308a, Atlanta, GA 30322, USA
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Ivnitsky JJ, Schäfer TV, Rejniuk VL, Vakunenkova OA. Secondary Dysfunction of the Intestinal Barrier in the Pathogenesis of Complications of Acute Poisoning. J EVOL BIOCHEM PHYS+ 2022; 58:1075-1098. [PMID: 36061072 PMCID: PMC9420239 DOI: 10.1134/s0022093022040123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 11/22/2022]
Abstract
The last decade has been marked by an exponential increase
in the number of publications on the physiological role of the normal
human gut microbiota. The idea of a symbiotic relationship between
the human organism and normal microbiota of its gastrointestinal
tract has been firmly established as an integral part of the current
biomedical paradigm. However, the type of this symbiosis varies
from mutualism to parasitism and depends on the functional state
of the host organism. Damage caused to the organism by external
agents can lead to the emergence of conditionally pathogenic properties
in the normal gut microbiota, mediated by humoral factors and affecting
the outcome of exogenous exposure. Among the substances produced
by symbiotic microbiota, there are an indefinite number of compounds
with systemic toxicity. Some occur in the intestinal chyme in potentially
lethal amounts in the case they enter the bloodstream quickly. The quick
entry of potential toxicants is prevented by the intestinal barrier
(IB), a set of structural elements separating the intestinal chyme
from the blood. Hypothetically, severe damage to the IB caused by
exogenous toxicants can trigger a leakage and subsequent systemic
redistribution of toxic substances of bacterial origin. Until recently,
the impact of such a redistribution on the outcome of acute exogenous
poisoning remained outside the view of toxicology. The present review
addresses causal relationships between the secondary dysfunction
of the IB and complications of acute poisoning. We characterize
acute systemic toxicity of such waste products of the normal gut microflora
as ammonia and endotoxins, and demonstrate their involvement in
the formation of such complications of acute poisoning as shock,
sepsis, cerebral insufficiency and secondary lung injuries. The
principles of assessing the functional state of the IB and the approaches
to its protection in acute poisoning are briefly considered.
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Affiliation(s)
- Ju. Ju. Ivnitsky
- Golikov Research Clinical Center of Toxicology, Federal Medical Biological Agency, St. Petersburg, Russia
| | - T. V. Schäfer
- State Scientific Research Test Institute of Military Medicine, Ministry of Defense of the Russian Federation, St. Petersburg, Russia
| | - V. L. Rejniuk
- Golikov Research Clinical Center of Toxicology, Federal Medical Biological Agency, St. Petersburg, Russia
| | - O. A. Vakunenkova
- Golikov Research Clinical Center of Toxicology, Federal Medical Biological Agency, St. Petersburg, Russia
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Ou Z, Dolmatova E, Mandavilli R, Qu H, Gafford G, White T, Valdivia A, Lassègue B, Hernandes MS, Griendling KK. Myeloid Poldip2 Contributes to the Development of Pulmonary Inflammation by Regulating Neutrophil Adhesion in a Murine Model of Acute Respiratory Distress Syndrome. J Am Heart Assoc 2022; 11:e025181. [PMID: 35535614 PMCID: PMC9238549 DOI: 10.1161/jaha.121.025181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background Lung injury, a severe adverse outcome of lipopolysaccharide-induced acute respiratory distress syndrome, is attributed to excessive neutrophil recruitment and effector response. Poldip2 (polymerase δ-interacting protein 2) plays a critical role in regulating endothelial permeability and leukocyte recruitment in acute inflammation. Thus, we hypothesized that myeloid Poldip2 is involved in neutrophil recruitment to inflamed lungs. Methods and Results After characterizing myeloid-specific Poldip2 knockout mice, we showed that at 18 hours post-lipopolysaccharide injection, bronchoalveolar lavage from myeloid Poldip2-deficient mice contained fewer inflammatory cells (8 [4-16] versus 29 [12-57]×104/mL in wild-type mice) and a smaller percentage of neutrophils (30% [28%-34%] versus 38% [33%-41%] in wild-type mice), while the main chemoattractants for neutrophils remained unaffected. In vitro, Poldip2-deficient neutrophils responded as well as wild-type neutrophils to inflammatory stimuli with respect to neutrophil extracellular trap formation, reactive oxygen species production, and induction of cytokines. However, neutrophil adherence to a tumor necrosis factor-α stimulated endothelial monolayer was inhibited by Poldip2 depletion (225 [115-272] wild-type [myePoldip2+/+] versus 133 [62-178] myeloid-specific Poldip2 knockout [myePoldip2-/-] neutrophils) as was transmigration (1.7 [1.3-2.1] versus 1.1 [1.0-1.4] relative to baseline transmigration). To determine the underlying mechanism, we examined the surface expression of β2-integrin, its binding to soluble intercellular adhesion molecule 1, and Pyk2 phosphorylation. Surface expression of β2-integrins was not affected by Poldip2 deletion, whereas β2-integrins and Pyk2 were less activated in Poldip2-deficient neutrophils. Conclusions These results suggest that myeloid Poldip2 is involved in β2-integrin activation during the inflammatory response, which in turn mediates neutrophil-to-endothelium adhesion in lipopolysaccharide-induced acute respiratory distress syndrome.
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Affiliation(s)
- Ziwei Ou
- Division of Cardiology Department of Medicine Emory University Atlanta GA.,Department of Cardiovascular Medicine Xiangya HospitalCentral South University Changsha China
| | - Elena Dolmatova
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Rohan Mandavilli
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Hongyan Qu
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Georgette Gafford
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Taylor White
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Alejandra Valdivia
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Bernard Lassègue
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Marina S Hernandes
- Division of Cardiology Department of Medicine Emory University Atlanta GA
| | - Kathy K Griendling
- Division of Cardiology Department of Medicine Emory University Atlanta GA
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NR4A1 Promotes LPS-Induced Acute Lung Injury through Inhibition of Opa1-Mediated Mitochondrial Fusion and Activation of PGAM5-Related Necroptosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6638244. [PMID: 35222801 PMCID: PMC8881136 DOI: 10.1155/2022/6638244] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/31/2021] [Accepted: 02/03/2022] [Indexed: 12/17/2022]
Abstract
Mitochondrial dysfunction and necroptosis have been perceived as the primary molecular mechanisms underscoring acute lung injury. Meanwhile, nuclear receptor subfamily 4 group A member 1 (NR4A1) is considered a regulator of inflammation-related endothelial injury in lung tissue although the downstream molecular events remain elusive. In this study, we employed NR4A1-/- mice to decipher the role of NR4A1 in the onset and progression of acute lung injury with a focus on mitochondrial damage and necroptosis. Our results demonstrated that NR4A1 was significantly upregulated in lipopolysaccharide- (LPS-) treated lung tissues. Knockout of NR4A1 overtly improved lung tissue morphology, inhibited inflammation, and reduced oxidative stress in LPS-treated lung tissue. A cell signaling study suggested that NR4A1 deletion repressed levels of PGAM5 and attenuated LPS-mediated necroptosis in primary murine alveolar epithelial type II (ATII) cells, the effects of which were mitigated by PGAM5 overexpression. Moreover, LPS-mediated mitochondrial injury including mitochondrial membrane potential collapse and mitochondrial oxidative stress was drastically improved by NR4A1 deletion. Furthermore, NR4A1 deletion preserved mitochondrial homeostasis through activation of Opa1-related mitochondrial fusion. Silencing of Opa1 triggered mitochondrial dysfunction in NR4A1-deleted ATII cells. Taken together, our data identified NR4A1 as a novel regulator of LPS-related acute lung injury through regulation of mitochondrial fusion and necroptosis, indicating therapeutic promises of targeting NR4A1 in the treatment of acute lung injury in clinical practice.
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Poldip2/Nox4 Mediates Lipopolysaccharide-Induced Oxidative Stress and Inflammation in Human Lung Epithelial Cells. Mediators Inflamm 2022; 2022:6666022. [PMID: 35140544 PMCID: PMC8818432 DOI: 10.1155/2022/6666022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 11/10/2021] [Accepted: 12/30/2021] [Indexed: 12/05/2022] Open
Abstract
NADPH oxidase 4 (Nox4) is an important source of reactive oxygen species (ROS) production, and its expression is increased in lipopolysaccharide- (LPS-) stimulated lung epithelial cells. Polymerase δ-interacting protein 2 (Poldip2) has been proved to bind Nox4 and participates in oxidative stress and inflammation. However, the role of Poldip2/Nox4 in LPS-induced oxidative stress and inflammation in lung epithelial cells remains unclear. Cell viability was measured via MTT assays. The expression of Poldip2, Nox4, heme oxygenase-1 (HO-1), cyclooxygenase-2 (COX-2), AKT, and p-AKT was detected by Western blotting and/or immunofluorescence. Poldip2 and Nox4 interaction was analyzed via coimmunoprecipitation (Co-IP) assay. NADPH enzymatic activity and production of ROS, prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were assessed simultaneously. The small interfering RNA (siRNA) or plasmid targeting Nox4 was used to downregulate or upregulate Nox4, and the lentiviral vector encoding Poldip2 was used to downregulate or upregulate Poldip2. The present study demonstrated that LPS stimulation significantly increased the protein levels of Poldip2 and Nox4 and proved that Poldip2 interacted with Nox4 proved by Co-IP. Importantly, Poldip2 acted as an upstream regulator of Nox4. The increased expression of Nox4 and COX-2; NADPH enzymatic activity; production of ROS, PGE2, TNF-α, and IL-1β; and decreased HO-1 expression were significantly suppressed by lentiviral Poldip2 shRNA downregulation but were increased by lentiviral upregulation of Poldip2. Furthermore, inhibiting of PI3K-AKT signaling notably attenuated LPS-induced Poldip2/Nox4 activation. Our study demonstrated that Poldip2 mediates LPS-induced oxidative stress and inflammation via interaction with Nox4 and was regulated by the PI3K-AKT signaling. Targeting Poldip2 could be a beneficial therapeutic strategy for the treatment of ALI.
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Lassègue B, Kumar S, Mandavilli R, Wang K, Tsai M, Kang DW, Demos C, Hernandes MS, San Martín A, Taylor WR, Jo H, Griendling KK. Characterization of Poldip2 knockout mice: Avoiding incorrect gene targeting. PLoS One 2021; 16:e0247261. [PMID: 34928942 PMCID: PMC8687530 DOI: 10.1371/journal.pone.0247261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 11/17/2021] [Indexed: 01/11/2023] Open
Abstract
POLDIP2 is a multifunctional protein whose roles are only partially understood. Our laboratory previously reported physiological studies performed using a mouse gene trap model, which suffered from three limitations: perinatal lethality in homozygotes, constitutive Poldip2 inactivation and inadvertent downregulation of the adjacent Tmem199 gene. To overcome these limitations, we developed a new conditional floxed Poldip2 model. The first part of the present study shows that our initial floxed mice were affected by an unexpected mutation, which was not readily detected by Southern blotting and traditional PCR. It consisted of a 305 kb duplication around Poldip2 with retention of the wild type allele and could be traced back to the original targeted ES cell clone. We offer simple suggestions to rapidly detect similar accidents, which may affect genome editing using both traditional and CRISPR-based methods. In the second part of the present study, correctly targeted floxed Poldip2 mice were generated and used to produce a new constitutive knockout line by crossing with a Cre deleter. In contrast to the gene trap model, many homozygous knockout mice were viable, in spite of having no POLDIP2 expression. To further characterize the effects of Poldip2 ablation in the vasculature, RNA-seq and RT-qPCR experiments were performed in constitutive knockout arteries. Results show that POLDIP2 inactivation affects multiple cellular processes and provide new opportunities for future in-depth study of its functions.
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Affiliation(s)
- Bernard Lassègue
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - Sandeep Kumar
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Rohan Mandavilli
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - Keke Wang
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - Michelle Tsai
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - Dong-Won Kang
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Catherine Demos
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Marina S. Hernandes
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - Alejandra San Martín
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
| | - W. Robert Taylor
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
- Division of Cardiology, Atlanta VA Medical Center, Decatur, GA, United States of America
| | - Hanjoong Jo
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Kathy K. Griendling
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA, United States of America
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11
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Eidson LN, Gao Q, Qu H, Kikuchi DS, Campos ACP, Faidley EA, Sun YY, Kuan CY, Pagano RL, Lassègue B, Tansey MG, Griendling KK, Hernandes MS. Poldip2 controls leukocyte infiltration into the ischemic brain by regulating focal adhesion kinase-mediated VCAM-1 induction. Sci Rep 2021; 11:5533. [PMID: 33692398 PMCID: PMC7970934 DOI: 10.1038/s41598-021-84987-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/22/2021] [Indexed: 11/29/2022] Open
Abstract
Stroke is a multiphasic process involving a direct ischemic brain injury which is then exacerbated by the influx of immune cells into the brain tissue. Activation of brain endothelial cells leads to the expression of adhesion molecules such vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells, further increasing leukocyte recruitment. Polymerase δ-interacting protein 2 (Poldip2) promotes brain vascular inflammation and leukocyte recruitment via unknown mechanisms. This study aimed to define the role of Poldip2 in mediating vascular inflammation and leukocyte recruitment following cerebral ischemia. Cerebral ischemia was induced in Poldip2+/+ and Poldip2+/- mice and brains were isolated and processed for flow cytometry or RT-PCR. Cultured rat brain microvascular endothelial cells were used to investigate the effect of Poldip2 depletion on focal adhesion kinase (FAK)-mediated VCAM-1 induction. Poldip2 depletion in vivo attenuated the infiltration of myeloid cells, inflammatory monocytes/macrophages and decreased the induction of adhesion molecules. Focusing on VCAM-1, we demonstrated mechanistically that FAK activation was a critical intermediary in Poldip2-mediated VCAM-1 induction. In conclusion, Poldip2 is an important mediator of endothelial dysfunction and leukocyte recruitment. Thus, Poldip2 could be a therapeutic target to improve morbidity following ischemic stroke.
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Affiliation(s)
- Lori N Eidson
- Department of Physiology, Emory University, Atlanta, GA, 30322, USA
| | - Qingzeng Gao
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Hongyan Qu
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Daniel S Kikuchi
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Ana Carolina P Campos
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
- Department of Neuroscience, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Elizabeth A Faidley
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Yu-Yo Sun
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22904, USA
| | - Chia-Yi Kuan
- Department of Neuroscience, University of Virginia, Charlottesville, VA, 22904, USA
| | - Rosana L Pagano
- Department of Neuroscience, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Bernard Lassègue
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Malú G Tansey
- Department of Physiology, Emory University, Atlanta, GA, 30322, USA
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, College of Medicine, Normal Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, 32610, USA
- Department of Neurology, Center for Translational Research in Neurodegenerative Disease, College of Medicine, Normal Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, 32610, USA
| | - Kathy K Griendling
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA
| | - Marina S Hernandes
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, 308-C WMB, Atlanta, GA, 30322, USA.
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12
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Nan CC, Zhang N, Cheung KCP, Zhang HD, Li W, Hong CY, Chen HS, Liu XY, Li N, Cheng L. Knockdown of lncRNA MALAT1 Alleviates LPS-Induced Acute Lung Injury via Inhibiting Apoptosis Through the miR-194-5p/FOXP2 Axis. Front Cell Dev Biol 2020; 8:586869. [PMID: 33117815 PMCID: PMC7575725 DOI: 10.3389/fcell.2020.586869] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/02/2020] [Indexed: 01/07/2023] Open
Abstract
Purpose We aimed to identify and verify the key genes and lncRNAs associated with acute lung injury (ALI) and explore the pathogenesis of ALI. Research showed that lower expression of the lncRNA metastasis-associated lung carcinoma transcript 1 (MALAT1) alleviates lung injury induced by lipopolysaccharide (LPS). Nevertheless, the mechanisms of MALAT1 on cellular apoptosis remain unclear in LPS-stimulated ALI. We investigated the mechanism of MALAT1 in modulating the apoptosis of LPS-induced human pulmonary alveolar epithelial cells (HPAEpiC). Methods Differentially expressed lncRNAs between the ALI samples and normal controls were identified using gene expression profiles. ALI-related genes were determined by the overlap of differentially expressed genes (DEGs), genes correlated with lung, genes correlated with key lncRNAs, and genes sharing significantly high proportions of microRNA targets with MALAT1. Quantitative real-time PCR (qPCR) was applied to detect the expression of MALAT1, microRNA (miR)-194-5p, and forkhead box P2 (FOXP2) mRNA in 1 μg/ml LPS-treated HPAEpiC. MALAT1 knockdown vectors, miR-194-5p inhibitors, and ov-FOXP2 were constructed and used to transfect HPAEpiC. The influence of MALAT1 knockdown on LPS-induced HPAEpiC proliferation and apoptosis via the miR-194-5p/FOXP2 axis was determined using Cell counting kit-8 (CCK-8) assay, flow cytometry, and Western blotting analysis, respectively. The interactions between MALAT1, miR-194-5p, and FOXP2 were verified using dual-luciferase reporter gene assay. Results We identified a key lncRNA (MALAT1) and three key genes (EYA1, WNT5A, and FOXP2) that are closely correlated with the pathogenesis of ALI. LPS stimulation promoted MALAT1 expression and apoptosis and also inhibited HPAEpiC viability. MALAT1 knockdown significantly improved viability and suppressed the apoptosis of LPS-stimulated HPAEpiC. Moreover, MALAT1 directly targeted miR-194-5p, a downregulated miRNA in LPS-stimulated HPAEpiC, when FOXP2 was overexpressed. MALAT1 knockdown led to the overexpression of miR-194-5p and restrained FOXP2 expression. Furthermore, inhibition of miR-194-5p exerted a rescue effect on MALAT1 knockdown of FOXP2, whereas the overexpression of FOXP2 reversed the effect of MALAT1 knockdown on viability and apoptosis of LPS-stimulated HPAEpiC. Conclusion Our results demonstrated that MALAT1 knockdown alleviated HPAEpiC apoptosis by competitively binding to miR-194-5p and then elevating the inhibitory effect on its target FOXP2. These data provide a novel insight into the role of MALAT1 in the progression of ALI and potential diagnostic and therapeutic strategies for ALI patients.
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Affiliation(s)
- Chuan-Chuan Nan
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Ning Zhang
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China.,Department of Stomatology Center, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Kenneth C P Cheung
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Hua-Dong Zhang
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Wei Li
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Cheng-Ying Hong
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Huai-Sheng Chen
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Xue-Yan Liu
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Nan Li
- Department of Stomatology Center, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Lixin Cheng
- Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
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13
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Dolmatova EV, Wang K, Mandavilli R, Griendling KK. The effects of sepsis on endothelium and clinical implications. Cardiovasc Res 2020; 117:60-73. [PMID: 32215570 DOI: 10.1093/cvr/cvaa070] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/03/2020] [Accepted: 03/20/2020] [Indexed: 12/15/2022] Open
Abstract
ABSTRACT Sepsis accounts for nearly 700 000 deaths in Europe annually and is caused by an overwhelming host response to infection resulting in organ failure. The endothelium is an active contributor to sepsis and as such represents a major target for therapy. During sepsis, endothelial cells amplify the immune response and activate the coagulation system. They are both a target and source of inflammation and serve as a link between local and systemic immune responses. In response to cytokines produced by immune cells, the endothelium expresses adhesion molecules and produces vasoactive compounds, inflammatory cytokines, and chemoattractants, thus switching from an anticoagulant to procoagulant state. These responses contribute to local control of infection, but systemic activation can lead to microvascular thrombosis, capillary permeability, hypotension, tissue hypoxia, and ultimately tissue damage. This review focuses on the role of the endothelium in leucocyte adhesion and transmigration as well as production of reactive oxygen and nitrogen species, microRNAs and cytokines, formation of signalling microparticles, and disseminated intravascular coagulation. We also discuss alterations in endothelial permeability and apoptosis. Finally, we review the diagnostic potential of endothelial markers and endothelial pathways as therapeutic targets for this devastating disease.
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Affiliation(s)
- Elena V Dolmatova
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Keke Wang
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Rohan Mandavilli
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Kathy K Griendling
- Division of Cardiology, Department of Medicine, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA
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14
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Kikuchi DS, Campos ACP, Qu H, Forrester SJ, Pagano RL, Lassègue B, Sadikot RT, Griendling KK, Hernandes MS. Poldip2 mediates blood-brain barrier disruption in a model of sepsis-associated encephalopathy. J Neuroinflammation 2019; 16:241. [PMID: 31779628 PMCID: PMC6883676 DOI: 10.1186/s12974-019-1575-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/29/2019] [Indexed: 11/10/2022] Open
Abstract
Background Sepsis-associated encephalopathy (SAE), a diffuse cerebral dysfunction in the absence of direct CNS infection, is associated with increased rates of mortality and morbidity in patients with sepsis. Increased cytokine production and disruption of the blood-brain barrier (BBB) are implicated in the pathogenesis of SAE. The induction of pro-inflammatory mediators is driven, in part, by activation of NF-κΒ. Lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, potently activates NF-κΒ and its downstream targets, including cyclooxygenase-2 (Cox-2). Cox-2 catalyzes prostaglandin synthesis and in the brain prostaglandin, E2 is capable of inducing endothelial permeability. Depletion of polymerase δ-interacting protein 2 (Poldip2) has previously been reported to attenuate BBB disruption, possibly via regulation of NF-κΒ, in response to ischemic stroke. Here we investigated Poldip2 as a novel regulator of NF-κΒ/cyclooxygenase-2 signaling in an LPS model of SAE. Methods Intraperitoneal injections of LPS (18 mg/kg) were used to induce BBB disruption in Poldip2+/+ and Poldip2+/− mice. Changes in cerebral vascular permeability and the effect of meloxicam, a selective Cox-2 inhibitor, were assessed by Evans blue dye extravasation. Cerebral cortices of Poldip2+/+ and Poldip2+/− mice were further evaluated by immunoblotting and ELISA. To investigate the role of endothelial Poldip2, immunofluorescence microscopy and immunoblotting were performed to study the effect of siPoldip2 on LPS-mediated NF-κΒ subunit p65 translocation and Cox-2 induction in rat brain microvascular endothelial cells. Finally, FITC-dextran transwell assay was used to assess the effect of siPoldip2 on LPS-induced endothelial permeability. Results Heterozygous deletion of Poldip2 conferred protection against LPS-induced BBB permeability. Alterations in Poldip2+/+ BBB integrity were preceded by induction of Poldip2, p65, and Cox-2, which was not observed in Poldip2+/− mice. Consistent with these findings, prostaglandin E2 levels were significantly elevated in Poldip2+/+ cerebral cortices compared to Poldip2+/− cortices. Treatment with meloxicam attenuated LPS-induced BBB permeability in Poldip2+/+ mice, while having no significant effect in Poldip2+/− mice. Moreover, silencing of Poldip2 in vitro blocked LPS-induced p65 nuclear translocation, Cox-2 expression, and endothelial permeability. Conclusions These data suggest Poldip2 mediates LPS-induced BBB disruption by regulating NF-κΒ subunit p65 activation and Cox-2 and prostaglandin E2 induction. Consequently, targeted inhibition of Poldip2 may provide clinical benefit in the prevention of sepsis-induced BBB disruption. Electronic supplementary material The online version of this article (10.1186/s12974-019-1575-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel S Kikuchi
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA
| | | | - Hongyan Qu
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA
| | - Steven J Forrester
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA
| | - Rosana L Pagano
- Division of Neuroscience, Hospital Sírio-Libanês, São Paulo, SP, Brazil
| | - Bernard Lassègue
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA
| | - Ruxana T Sadikot
- Division of Pulmonary and Critical Care, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Kathy K Griendling
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA
| | - Marina S Hernandes
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 101 Woodruff Circle, 308 WMB, Atlanta, GA, 30322, USA.
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