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Breslin JW, Yuan SY. Determination of Solute Permeability of Microvascular Endothelial Cell Monolayers In Vitro. Methods Mol Biol 2024; 2711:1-12. [PMID: 37776444 PMCID: PMC10928851 DOI: 10.1007/978-1-0716-3429-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/02/2023]
Abstract
The microvascular endothelium has a critical role in regulating the delivery of oxygen, nutrients, and water to the surrounding tissues. Under inflammatory conditions that accompany acute injury or disease, microvascular permeability becomes elevated. When microvascular hyperpermeability becomes uncontrolled or chronic, the excessive escape of plasma proteins into the surrounding tissue disrupts homeostasis and ultimately leads to organ dysfunction. Much remains to be learned about the mechanisms that control microvascular permeability. In addition to in vivo and isolated microvessel methods, the cultured endothelial cell monolayer protocol is an important tool that allows for understanding the specific, endothelial subcellular mechanisms that determine permeability of the endothelium to plasma proteins. In this chapter, two variations of the popular Transwell culture methodology to determine permeability to using fluorescently labeled tracers are presented. The strengths and weaknesses of this approach are also discussed.
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Affiliation(s)
- Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Sarah Y Yuan
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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2
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Wu J, Barkat MQ, Su J, Wu F, Tan D, Shen T, He Q, Qu M, Lu M, Cai J, Wu X, Xu C. Inhibition of non-muscular myosin light chain kinase accelerates the clearance of inflammatory cells by promoting the lysosome-mediated cell death. Biomed Pharmacother 2024; 170:115986. [PMID: 38056232 DOI: 10.1016/j.biopha.2023.115986] [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: 09/26/2023] [Revised: 12/01/2023] [Accepted: 12/02/2023] [Indexed: 12/08/2023] Open
Abstract
Infections like COVID-19 are the primary cause of death around the world because they can cause acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and sepsis. Inflammatory cells serve as crucial protective barriers in these diseases. However, excessive accumulation of inflammatory cells is also one of the major causes of organ damage. The non-muscular myosin light chain kinase (nmMLCK) plays crucial of cytoskeletal components involved in endothelial cell-matrix and cell-cell adhesion, integrity, and permeability. Our previous investigations found that ML-7, a specific inhibitor of MLCK, promoted neutrophil apoptosis through various signaling pathways. In this study, we found that knockout of MLCK significantly promote apoptosis of neutrophils and macrophages in the BALF of the LPS-induced ALI, meanwhile it had no effect on the apoptosis of neutrophils in the circulatory system. RNA-sequencing revealed that the effect of MLCK knockout in inducing apoptosis of inflammatory cells was mediated through lysosomes. Administering ML-7 into the lungs significantly promoted neutrophil apoptosis, accelerating their clearance. In the LPS- or CLP-induced sepsis models, ML-7 administration significantly improves the apoptosis of inflammatory cells, especially neutrophils, at the infection site but had no impact on neutrophils in the circulatory system. ML-7 also significantly improved the survival rate of mice with LPS- or CLP-induced sepsis. Taken together, we found that MLCK plays a crucial role in the survival of inflammatory cells at the infection site. Inhibiting MLCK significantly induces apoptosis of inflammatory cells at the infection site, promoting inflammation resolution, with no impact of the circulatory system.
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Affiliation(s)
- Junsong Wu
- Department of Orthopaedics, the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, China
| | - Muhammad Qasim Barkat
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiakun Su
- Technology Center, China Tobacco Jiangxi Industrial Co. Ltd., Nanchang 330096, China
| | - Fugen Wu
- Department of Pediatrics, the First People's Hospital of Wenling City, Wenling 317500, China
| | - Dan Tan
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Tingyu Shen
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Qiangqiang He
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Meiyu Qu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Meiping Lu
- National Clinical Research Center for Child Health, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Jibao Cai
- Technology Center, China Tobacco Jiangxi Industrial Co. Ltd., Nanchang 330096, China
| | - Ximei Wu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China.
| | - Chengyun Xu
- Department of Pharmacology, School of Medcine, Hangzhou City University, 310015, China.
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3
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Breslin JW. Edema and lymphatic clearance: molecular mechanisms and ongoing challenges. Clin Sci (Lond) 2023; 137:1451-1476. [PMID: 37732545 PMCID: PMC11025659 DOI: 10.1042/cs20220314] [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: 06/03/2023] [Revised: 08/18/2023] [Accepted: 08/31/2023] [Indexed: 09/22/2023]
Abstract
Resolution of edema remains a significant clinical challenge. Conditions such as traumatic shock, sepsis, or diabetes often involve microvascular hyperpermeability, which leads to tissue and organ dysfunction. Lymphatic insufficiency due to genetic causes, surgical removal of lymph nodes, or infections, leads to varying degrees of tissue swelling that impair mobility and immune defenses. Treatment options are limited to management of edema as there are no specific therapeutics that have demonstrated significant success for ameliorating microvascular leakage or impaired lymphatic function. This review examines current knowledge about the physiological, cellular, and molecular mechanisms that control microvascular permeability and lymphatic clearance, the respective processes for interstitial fluid formation and removal. Clinical conditions featuring edema, along with potential future directions are discussed.
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Affiliation(s)
- Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, FL, U.S.A
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4
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Ottolini M, Sonkusare SK. The Calcium Signaling Mechanisms in Arterial Smooth Muscle and Endothelial Cells. Compr Physiol 2021; 11:1831-1869. [PMID: 33792900 PMCID: PMC10388069 DOI: 10.1002/cphy.c200030] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The contractile state of resistance arteries and arterioles is a crucial determinant of blood pressure and blood flow. Physiological regulation of arterial contractility requires constant communication between endothelial and smooth muscle cells. Various Ca2+ signals and Ca2+ -sensitive targets ensure dynamic control of intercellular communications in the vascular wall. The functional effect of a Ca2+ signal on arterial contractility depends on the type of Ca2+ -sensitive target engaged by that signal. Recent studies using advanced imaging methods have identified the spatiotemporal signatures of individual Ca2+ signals that control arterial and arteriolar contractility. Broadly speaking, intracellular Ca2+ is increased by ion channels and transporters on the plasma membrane and endoplasmic reticular membrane. Physiological roles for many vascular Ca2+ signals have already been confirmed, while further investigation is needed for other Ca2+ signals. This article focuses on endothelial and smooth muscle Ca2+ signaling mechanisms in resistance arteries and arterioles. We discuss the Ca2+ entry pathways at the plasma membrane, Ca2+ release signals from the intracellular stores, the functional and physiological relevance of Ca2+ signals, and their regulatory mechanisms. Finally, we describe the contribution of abnormal endothelial and smooth muscle Ca2+ signals to the pathogenesis of vascular disorders. © 2021 American Physiological Society. Compr Physiol 11:1831-1869, 2021.
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Affiliation(s)
- Matteo Ottolini
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Swapnil K Sonkusare
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA.,Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
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5
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Chi Y, Liu X, Chai J. A narrative review of changes in microvascular permeability after burn. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:719. [PMID: 33987417 PMCID: PMC8106041 DOI: 10.21037/atm-21-1267] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Objective We aimed to review and discuss some of the latest research results related to post-burn pathophysiological changes and provide some clues for future study. Background Burns are one of the most common and serious traumas and consist of a series of pathophysiological changes of thermal injury. Accompanied by thermal damage to skin and soft tissues, inflammatory mediators are released in large quantities. Changes in histamine, bradykinin, and cytokines such as vascular endothelial growth factor (VEGF), metabolic factors such as adenosine triphosphate (ATP), and activated neutrophils all affect the body’s vascular permeability. Methods We searched articles with subject words “microvascular permeability”, “burn” “endothelium”, and “endothelial barrier” in PubMed in English published from the beginning of database to Dec, 2020. Conclusions The essence of burn shock is the rapid and extensive fluid transfer in burn and non-burn tissue. After severe burns, the local and systemic vascular permeability increase, causing intravascular fluid extravasation, leading to a progressive decrease in effective circulation volume, an increase in systemic vascular resistance, a decrease in cardiac output, peripheral tissue edema, multiple organ failure, and even death. There are many cells, tissues, mediators and structures involved in the pathophysiological process of the damage to vascular permeability. Ulinastatin is a promising agent for this problem.
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Affiliation(s)
- Yunfei Chi
- Burn Institute, The Fourth Medical Center of the PLA General Hospital, Beijing, China
| | - Xiangyu Liu
- Burn Institute, The Fourth Medical Center of the PLA General Hospital, Beijing, China
| | - Jiake Chai
- Burn Institute, The Fourth Medical Center of the PLA General Hospital, Beijing, China
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6
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Srivastava N, Tauseef M, Amin R, Joshi B, Joshi JC, Kini V, Klomp J, Li W, Knezevic N, Barbera N, Siddiqui S, Obukhov A, Karginov A, Levitan I, Komarova Y, Mehta D. Noncanonical function of long myosin light chain kinase in increasing ER-PM junctions and augmentation of SOCE. FASEB J 2020; 34:12805-12819. [PMID: 32772419 PMCID: PMC7496663 DOI: 10.1096/fj.201902462rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 06/26/2020] [Accepted: 07/16/2020] [Indexed: 12/13/2022]
Abstract
Increased endothelial permeability leads to excessive exudation of plasma proteins and leukocytes in the interstitium, which characterizes several vascular diseases including acute lung injury. The myosin light chain kinase long (MYLK-L) isoform is canonically known to regulate the endothelial permeability by phosphorylating myosin light chain (MLC-P). Compared to the short MYLK isoform, MYLK-L contains an additional stretch of ~919 amino acid at the N-terminus of unknown function. We show that thapsigargin and thrombin-induced SOCE was markedly reduced in Mylk-L-/- endothelial cells (EC) or MYLK-L-depleted human EC. These agonists also failed to increase endothelial permeability in MYLK-L-depleted EC and Mylk-L-/- lungs, thus demonstrating the novel role of MYLK-L-induced SOCE in increasing vascular permeability. MYLK-L augmented SOCE by increasing endoplasmic reticulum (ER)-plasma membrane (PM) junctions and STIM1 translocation to these junctions. Transduction of N-MYLK domain (amino acids 1-919 devoid of catalytic activity) into Mylk-L-/- EC rescued SOCE to the level seen in control EC in a STIM1-dependent manner. N-MYLK-induced SOCE augmented endothelial permeability without MLC-P via an actin-binding motif, DVRGLL. Liposomal-mediated delivery of N-MYLK mutant but not ∆DVRGLL-N-MYLK mutant in Mylk-L-/- mice rescued vascular permeability increase in response to endotoxin, indicating that targeting of DVRGLL motif within MYLK-L may limit SOCE-induced vascular hyperpermeability.
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Affiliation(s)
- Nityanand Srivastava
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Mohammad Tauseef
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
- Department of Pharmaceutical SciencesChicago State University College of PharmacyChicagoILUSA
| | - Ruhul Amin
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Bhagwati Joshi
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Jagdish Chandra Joshi
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Vidisha Kini
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Jennifer Klomp
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Weenan Li
- Department of Cellular and Integrative PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Nebojsa Knezevic
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Nicolas Barbera
- Department of MedicineThe Uniiversity of IllinoisChicagoILUSA
| | - Shahid Siddiqui
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Alexander Obukhov
- Department of Cellular and Integrative PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Andrei Karginov
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Irena Levitan
- Department of MedicineThe Uniiversity of IllinoisChicagoILUSA
| | - Yulia Komarova
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Dolly Mehta
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
- Department of Pharmaceutical SciencesChicago State University College of PharmacyChicagoILUSA
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7
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Braun DJ, Bachstetter AD, Sudduth TL, Wilcock DM, Watterson DM, Van Eldik LJ. Genetic knockout of myosin light chain kinase (MLCK210) prevents cerebral microhemorrhages and attenuates neuroinflammation in a mouse model of vascular cognitive impairment and dementia. GeroScience 2019; 41:671-679. [PMID: 31104189 PMCID: PMC6885026 DOI: 10.1007/s11357-019-00072-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/25/2019] [Indexed: 12/15/2022] Open
Abstract
The blood-brain barrier (BBB) is critical in maintenance of brain homeostasis, and loss of its functional integrity is a key feature across a broad range of neurological insults. This includes both acute injuries such as traumatic brain injury and stroke, as well as more chronic pathologies associated with aging, such as vascular cognitive impairment and dementia (VCID). A specific form of myosin light chain kinase (MLCK210) is a major regulator of barrier integrity in general, including the BBB. Studies have demonstrated the potential of MLCK210 as a therapeutic target for peripheral disorders involving tissue barrier dysfunction, but less is known about its potential as a target for chronic neurologic disorders. We report here that genetic knockout (KO) of MLCK210 protects against cerebral microhemorrhages and neuroinflammation induced by chronic dietary hyperhomocysteinemia. Overall, the results are consistent with an accumulating body of evidence supporting MLCK210 as a potential therapeutic target for tissue barrier dysfunction and specifically implicate it in BBB dysfunction and neuroinflammation in a model of VCID.
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Affiliation(s)
- David J Braun
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA
| | - Adam D Bachstetter
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA
- Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Tiffany L Sudduth
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - Donna M Wilcock
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - D Martin Watterson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Linda J Van Eldik
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA.
- Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA.
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA.
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8
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Attenuation of endothelial phosphatidylserine exposure decreases ischemia-reperfusion induced changes in microvascular permeability. J Trauma Acute Care Surg 2019. [PMID: 29538229 DOI: 10.1097/ta.0000000000001891] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Translocation of phosphatidylserine from the inner leaflet to the outer leaflet of the endothelial membrane via phospholipid scramblase-1 (PLSCR1) is an apoptotic signal responsible for the loss of endothelial barrier integrity after ischemia-reperfusion injury (IRI). We hypothesized that inhibiting phosphatidylserine expression on endothelial cells would attenuate IRI induced increases in hydraulic permeability (Lp). METHODS Mesenteric Lp was measured in rat post-capillary mesenteric venules subjected to IRI via superior mesenteric artery (SMA) occlusion (45 minutes) and release (300 minutes) in conjunction with several inhibitors of phosphatidylserine exposure as follows: (1) inhibition of PLSCR1 translocation (dithioerythritol, n = 3), (2) inhibition of PLSCR1 membrane trafficking (2-bromopalmitate [2-BP], n = 3), and (3) inhibition of ion exchange necessary for PLSCR1 function (4,4'-Diisothiocyano-2,2'-stilbenedisulfonic acid [DIDS], n = 3). Under the same IRI conditions, rats were also administered targeted inhibitors of phosphatidylserine exposure including knockdown of PLSCR1 (n = 3) using RNA interference (RNAi), and as a potential therapeutic tool Diannexin, a selective phosphatidylserine blocker (n = 3). RESULTS During IRI net Lp increased by 80% (p < 0.01). Net reductions of Lp were accomplished by 2-BP (46% reduction, p = 0.005), combined DET + 2-BP + DIDS (32% reduction, p = 0.04), RNAi (55% reduction, p = 0.002), Diannexin administered pre-SMA artery occlusion (73% reduction, p = 0.001), and post-SMA occlusion (70% reduction, p = 0.002). CONCLUSION Phosphatidylserine exposure is a key event in the pathogenesis of microvascular dysfunction during IRI. Clinically, inhibition of phosphatidylserine exposure is a promising strategy that may 1 day be used to mitigate the effects of IRI.
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9
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Endothelial Protrusions in Junctional Integrity and Barrier Function. CURRENT TOPICS IN MEMBRANES 2018; 82:93-140. [PMID: 30360784 DOI: 10.1016/bs.ctm.2018.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Endothelial cells of the microcirculation form a semi-permeable diffusion barrier between the blood and tissues. This permeability of the endothelium, particularly in the capillaries and postcapillary venules, is a normal physiological function needed for blood-tissue exchange in the microcirculation. During inflammation, microvascular permeability increases dramatically and can lead to tissue edema, which in turn can lead to dysfunction of tissues and organs. The molecular mechanisms that control the barrier function of endothelial cells have been under investigation for several decades and remain an important topic due to the potential for discovery of novel therapeutic strategies to reduce edema. This review highlights current knowledge of the cellular and molecular mechanisms that lead to endothelial hyperpermeability during inflammatory conditions associated with injury and disease. This includes a discussion of recent findings demonstrating temporal protrusions by endothelial cells that may contribute to intercellular junction integrity between endothelial cells and affect the diffusion distance for solutes via the paracellular pathway.
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10
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Arnaud C, Bouyon S, Recoquillon S, Brasseur S, Lemarié E, Briançon-Marjollet A, Gonthier B, Toral M, Faury G, Martinez MC, Andriantsitohaina R, Pepin JL. Nonmuscle Myosin Light Chain Kinase: A Key Player in Intermittent Hypoxia-Induced Vascular Alterations. J Am Heart Assoc 2018; 7:JAHA.117.007893. [PMID: 29371201 PMCID: PMC5850262 DOI: 10.1161/jaha.117.007893] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background Obstructive sleep apnea is characterized by repetitive pharyngeal collapses during sleep, leading to intermittent hypoxia (IH), the main contributor of obstructive sleep apnea–related cardiovascular morbidity. In patients and rodents with obstructive sleep apnea exposed to IH, vascular inflammation and remodeling, endothelial dysfunction, and circulating inflammatory markers are linked with IH severity. The nonmuscle myosin light chain kinase (nmMLCK) isoform contributes to vascular inflammation and oxidative stress in different cardiovascular and inflammatory diseases. Thus, in the present study, we hypothesized that nmMLCK plays a key role in the IH‐induced vascular dysfunctions and inflammatory remodeling. Methods and Results Twelve‐week‐old nmMLCK+/+ or nmMLCK−/− mice were exposed to 14‐day IH or normoxia. IH was associated with functional alterations characterized by an elevation of arterial blood pressure and stiffness and perturbations of NO signaling. IH caused endothelial barrier dysfunction (ie, reduced transendothelial resistance in vitro) and induced vascular oxidative stress associated with an inflammatory remodeling, characterized by an increased intima‐media thickness and an increased expression and activity of inflammatory markers, such as interferon‐γ and nuclear factor‐κB, in the vascular wall. Interestingly, nmMLCK deletion prevented all IH‐induced functional and structural alterations, including the restoration of NO signaling, correction of endothelial barrier integrity, and reduction of both oxidative stress and associated inflammatory response. Conclusions nmMLCK is a key mechanism in IH‐induced vascular oxidative stress and inflammation and both functional and structural remodeling.
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Affiliation(s)
- Claire Arnaud
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France .,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Sophie Bouyon
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Sylvain Recoquillon
- Université d'Angers Université Bretagne Loire, Angers, France.,INSERM UMR1063, Angers, France
| | - Sandrine Brasseur
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Emeline Lemarié
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Anne Briançon-Marjollet
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Brigitte Gonthier
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - Marta Toral
- Université d'Angers Université Bretagne Loire, Angers, France.,INSERM UMR1063, Angers, France
| | - Gilles Faury
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France
| | - M Carmen Martinez
- Université d'Angers Université Bretagne Loire, Angers, France.,INSERM UMR1063, Angers, France
| | | | - Jean-Louis Pepin
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France.,Laboratoire HP2, INSERM U1042, Grenoble, France.,Laboratoire d'Exploration Fonctionnelle Cardiovasculaire et Respiratoire, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
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11
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Doggett TM, Alves NG, Yuan SY, Breslin JW. Sphingosine-1-Phosphate Treatment Can Ameliorate Microvascular Leakage Caused by Combined Alcohol Intoxication and Hemorrhagic Shock. Sci Rep 2017; 7:4078. [PMID: 28642485 PMCID: PMC5481382 DOI: 10.1038/s41598-017-04157-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/10/2017] [Indexed: 11/09/2022] Open
Abstract
Fluid resuscitation following hemorrhagic shock is often problematic, with development of prolonged hypotension and edema. In addition, many trauma patients are also intoxicated, which generally worsens outcomes. We directly investigated how alcohol intoxication impacts hemorrhagic shock and resuscitation-induced microvascular leakage using a rat model with intravital microscopic imaging. We also tested the hypothesis that an endothelial barrier-protective bioactive lipid, sphingosine-1-phosphate (S1P), could ameliorate the microvascular leakage following alcohol intoxication plus hemorrhagic shock and resuscitation. Our results show that alcohol intoxication exacerbated hemorrhagic shock and resuscitation-induced hypotension and microvascular leakage. We next found that S1P effectively could reverse alcohol-induced endothelial barrier dysfunction using both cultured endothelial cell monolayer and in vivo models. Lastly, we observed that S1P administration ameliorated hypotension and microvascular leakage following combined alcohol intoxication and hemorrhagic shock, in a dose-related manner. These findings suggest the viability of using agonists that can improve microvascular barrier function to ameliorate trauma-induced hypotension, offering a novel therapeutic opportunity for potentially improving clinical outcomes in patients with multi-hit injuries.
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Affiliation(s)
- Travis M Doggett
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Natascha G Alves
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Sarah Y Yuan
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
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12
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Khapchaev AY, Shirinsky VP. Myosin Light Chain Kinase MYLK1: Anatomy, Interactions, Functions, and Regulation. BIOCHEMISTRY (MOSCOW) 2017; 81:1676-1697. [PMID: 28260490 DOI: 10.1134/s000629791613006x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review discusses and summarizes the results of molecular and cellular investigations of myosin light chain kinase (MLCK, MYLK1), the key regulator of cell motility. The structure and regulation of a complex mylk1 gene and the domain organization of its products is presented. The interactions of the mylk1 gene protein products with other proteins and posttranslational modifications of the mylk1 gene protein products are reviewed, which altogether might determine the role and place of MLCK in physiological and pathological reactions of cells and entire organisms. Translational potential of MLCK as a drug target is evaluated.
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Affiliation(s)
- A Y Khapchaev
- Russian Cardiology Research and Production Center, Moscow, 121552, Russia.
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13
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Crosstalk between Inflammation and ROCK/MLCK Signaling Pathways in Gastrointestinal Disorders with Intestinal Hyperpermeability. Gastroenterol Res Pract 2016; 2016:7374197. [PMID: 27746814 PMCID: PMC5056309 DOI: 10.1155/2016/7374197] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 07/12/2016] [Accepted: 07/19/2016] [Indexed: 12/18/2022] Open
Abstract
The barrier function of the intestine is essential for maintaining the normal homeostasis of the gut and mucosal immune system. Abnormalities in intestinal barrier function expressed by increased intestinal permeability have long been observed in various gastrointestinal disorders such as Crohn's disease (CD), ulcerative colitis (UC), celiac disease, and irritable bowel syndrome (IBS). Imbalance of metabolizing junction proteins and mucosal inflammation contributes to intestinal hyperpermeability. Emerging studies exploring in vitro and in vivo model system demonstrate that Rho-associated coiled-coil containing protein kinase- (ROCK-) and myosin light chain kinase- (MLCK-) mediated pathways are involved in the regulation of intestinal permeability. With this perspective, we aim to summarize the current state of knowledge regarding the role of inflammation and ROCK-/MLCK-mediated pathways leading to intestinal hyperpermeability in gastrointestinal disorders. In the near future, it may be possible to specifically target these specific pathways to develop novel therapies for gastrointestinal disorders associated with increased gut permeability.
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Haines RJ, Beard RS, Chen L, Eitnier RA, Wu MH. Interleukin-1β Mediates β-Catenin-Driven Downregulation of Claudin-3 and Barrier Dysfunction in Caco2 Cells. Dig Dis Sci 2016; 61:2252-2261. [PMID: 27074920 PMCID: PMC5517031 DOI: 10.1007/s10620-016-4145-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/22/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND IL-1β is a cytokine involved in mediating epithelial barrier dysfunction in the gut. It is known that IL-1β mediates activation of non-muscle myosin light chain kinase in epithelial cells, but the precise mechanism by which epithelial barrier dysfunction is induced by IL-1β is not understood. METHODS AND RESULTS Using a Caco2 cell model, we show that the expression of the tight junction protein, claudin-3, is transcriptionally downregulated by IL-1β treatment. In addition, after assessing protein and mRNA expression, and protein localization, we show that inhibition of nmMLCK rescues IL-1β-mediated decrease in claudin-3 expression as well as junction protein redistribution. Using chromatin immunoprecipitation assays, we also show that β-catenin targeting of the claudin-3 promoter occurs as a consequence of IL-1β-mediated epithelial barrier dysfunction, and inhibition of nmMLCK interferes with this interaction. CONCLUSIONS Taken together, these data represent the first line of evidence demonstrating nmMLCK regulation of claudin-3 expression in response to IL-1β-treated epithelial cells.
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Affiliation(s)
- R J Haines
- Department of Surgery, University of South Florida, Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 8, Office MDC 2012, Tampa, FL, 33612, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
| | - R S Beard
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, Tampa, FL, USA
| | - L Chen
- Department of Surgery, University of South Florida, Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 8, Office MDC 2012, Tampa, FL, 33612, USA
| | - R A Eitnier
- Department of Surgery, University of South Florida, Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 8, Office MDC 2012, Tampa, FL, 33612, USA
| | - M H Wu
- Department of Surgery, University of South Florida, Morsani College of Medicine, 12901 Bruce B. Downs Blvd., MDC 8, Office MDC 2012, Tampa, FL, 33612, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, USA.
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15
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Doggett TM, Breslin JW. Acute alcohol intoxication-induced microvascular leakage. Alcohol Clin Exp Res 2015; 38:2414-26. [PMID: 25257290 DOI: 10.1111/acer.12525] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 07/02/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Alcohol intoxication can increase inflammation and worsen injury, yet the mechanisms involved are not clear. We investigated whether acute alcohol intoxication increases microvascular permeability and investigated potential signaling mechanisms in endothelial cells that may be involved. METHODS Conscious rats received a 2.5 g/kg alcohol bolus via gastric catheters to produce acute intoxication. Microvascular leakage of intravenously administered fluorescein isothiocyanate (FITC)-conjugated albumin (FITC-albumin) from the mesenteric microcirculation was assessed by intravital microscopy. Endothelial-specific mechanisms were studied using cultured endothelial cell monolayers. Transendothelial electrical resistance (TER) served as an index of barrier function, before and after treatment with alcohol or its metabolite acetaldehyde. Pharmacologic agents were used to test the roles of alcohol metabolism, oxidative stress, p38 mitogen-activated protein kinase (MAPK), myosin light-chain kinase (MLCK), rho kinase (ROCK), and exchange protein activated by cAMP (Epac). VE-cadherin localization was investigated to assess junctional integrity. Rac1 and RhoA activation was assessed by ELISA assays. RESULTS Alcohol significantly increased FITC-albumin extravasation from the mesenteric microcirculation. Alcohol also significantly decreased TER and disrupted VE-cadherin organization at junctions. Acetaldehyde significantly decreased TER, but inhibition of alcohol dehydrogenase or application of a superoxide dismutase mimetic failed to prevent alcohol-induced decreases in TER. Inhibition of p38 MAPK, but not MLCK or ROCK, significantly attenuated the alcohol-induced barrier dysfunction. Alcohol rapidly decreased GTP-bound Rac1 but not RhoA during the drop in TER. Activation of Epac increased TER, but did not prevent alcohol from decreasing TER. However, activation of Epac after initiation of alcohol-induced barrier dysfunction quickly resolved TER to baseline levels. CONCLUSIONS Our results suggest that alcohol intoxication increases microvascular permeability to plasma proteins. The data also suggest the endothelial-specific mechanism involves the p38 MAPK, Rac1, and reorganization of VE-cadherin at junctions. Last, activation of Epac can quickly resolve alcohol-induced endothelial barrier dysfunction.
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Affiliation(s)
- Travis M Doggett
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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16
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Breslin JW, Zhang XE, Worthylake RA, Souza-Smith FM. Involvement of local lamellipodia in endothelial barrier function. PLoS One 2015; 10:e0117970. [PMID: 25658915 PMCID: PMC4320108 DOI: 10.1371/journal.pone.0117970] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/06/2015] [Indexed: 01/15/2023] Open
Abstract
Recently we observed that endothelial cells cultured in tightly confluent monolayers display frequent local lamellipodia, and that thrombin, an agent that increases endothelial permeability, reduces lamellipodia protrusions. This led us to test the hypothesis that local lamellipodia contribute to endothelial barrier function. Movements of subcellular structures containing GFP-actin or VE-cadherin-GFP expressed in endothelial cells were recorded using time-lapse microscopy. Transendothelial electrical resistance (TER) served as an index of endothelial barrier function. Changes in both lamellipodia dynamics and TER were assessed during baseline and after cells were treated with either the barrier-disrupting agent thrombin, or the barrier-stabilizing agent sphingosine-1-phosphate (S1P). The myosin II inhibitor blebbistatin was used to selectively block lamellipodia formation, and was used to test their role in the barrier function of endothelial cell monolayers and isolated, perfused rat mesenteric venules. Myosin light chain (MLC) phosphorylation was assessed by immunofluorescence microscopy. Rac1 and RhoA activation were evaluated using G-LISA assays. The role of Rac1 was tested with the specific inhibitor NSC23766 or by expressing wild-type or dominant negative GFP-Rac1. The results show that thrombin rapidly decreased both TER and the lamellipodia protrusion frequency. S1P rapidly increased TER in association with increased protrusion frequency. Blebbistatin nearly abolished local lamellipodia protrusions while cortical actin fibers and stress fibers remained intact. Blebbistatin also significantly decreased TER of cultured endothelial cells and increased permeability of isolated rat mesenteric venules. Both thrombin and S1P increased MLC phosphorylation and activation of RhoA. However, thrombin and S1P had differential impacts on Rac1, correlating with the changes in TER and lamellipodia protrusion frequency. Overexpression of Rac1 elevated, while NSC23766 and dominant negative Rac1 reduced barrier function and lamellipodia activity. Combined, these data suggest that local lamellipodia, driven by myosin II and Rac1, are important for dynamic changes in endothelial barrier integrity.
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Affiliation(s)
- Jerome W. Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
| | - Xun E. Zhang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Rebecca A. Worthylake
- Department of Pharmacology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Flavia M. Souza-Smith
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
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17
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Grek CL, Rhett JM, Ghatnekar GS. Cardiac to cancer: connecting connexins to clinical opportunity. FEBS Lett 2014; 588:1349-64. [PMID: 24607540 DOI: 10.1016/j.febslet.2014.02.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 12/26/2022]
Abstract
Gap junctions and their connexin components are indispensable in mediating the cellular coordination required for tissue and organ homeostasis. The critical nature of their existence mandates a connection to disease while at the same time offering therapeutic potential. Therapeutic intervention may be offered through the pharmacological and molecular disruption of the pathways involved in connexin biosynthesis, gap junction assembly, stabilization, or degradation. Chemical inhibitors aimed at closing connexin channels, peptide mimetics corresponding to short connexin sequences, and gene therapy approaches have been incredibly useful molecular tools in deciphering the complexities associated with connexin biology. Recently, therapeutic potential in targeting connexins has evolved from basic research in cell-based models to clinical opportunity in the form of human trials. Clinical promise is particularly evident with regards to targeting connexin43 in the context of wound healing. The following review is aimed at highlighting novel advances where the pharmacological manipulation of connexin biology has proven beneficial in animals or humans.
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Affiliation(s)
- Christina L Grek
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, United States
| | - J Matthew Rhett
- Department of Surgery, Division of General Surgery, Medical University of South Carolina, Charleston, SC, United States
| | - Gautam S Ghatnekar
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, United States.
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18
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Beard RS, Haines RJ, Wu KY, Reynolds JJ, Davis SM, Elliott JE, Malinin NL, Chatterjee V, Cha BJ, Wu MH, Yuan SY. Non-muscle Mlck is required for β-catenin- and FoxO1-dependent downregulation of Cldn5 in IL-1β-mediated barrier dysfunction in brain endothelial cells. J Cell Sci 2014; 127:1840-53. [PMID: 24522189 DOI: 10.1242/jcs.144550] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Aberrant elevation in the levels of the pro-inflammatory cytokine interleukin-1β (IL-1β) contributes to neuroinflammatory diseases. Blood-brain barrier (BBB) dysfunction is a hallmark phenotype of neuroinflammation. It is known that IL-1β directly induces BBB hyperpermeability but the mechanisms remain unclear. Claudin-5 (Cldn5) is a tight junction protein found at endothelial cell-cell contacts that are crucial for maintaining brain microvascular endothelial cell (BMVEC) integrity. Transcriptional regulation of Cldn5 has been attributed to the transcription factors β-catenin and forkhead box protein O1 (FoxO1), and the signaling molecules regulating their nuclear translocation. Non-muscle myosin light chain kinase (nmMlck, encoded by the Mylk gene) is a key regulator involved in endothelial hyperpermeability, and IL-1β has been shown to mediate nmMlck-dependent barrier dysfunction in epithelia. Considering these factors, we tested the hypothesis that nmMlck modulates IL-1β-mediated downregulation of Cldn5 in BMVECs in a manner that depends on transcriptional repression mediated by β-catenin and FoxO1. We found that treating BMVECs with IL-1β induced barrier dysfunction concomitantly with the nuclear translocation of β-catenin and FoxO1 and the repression of Cldn5. Most importantly, using primary BMVECs isolated from mice null for nmMlck, we identified that Cldn5 repression caused by β-catenin and FoxO1 in IL-1β-mediated barrier dysfunction was dependent on nmMlck.
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Affiliation(s)
- Richard S Beard
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Rossi JL, Todd T, Bazan NG, Belayev L. Inhibition of Myosin light-chain kinase attenuates cerebral edema after traumatic brain injury in postnatal mice. J Neurotrauma 2013; 30:1672-9. [PMID: 23984869 DOI: 10.1089/neu.2013.2898] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Traumatic brain injury (TBI) in children less than 8 years of age leads to decline in intelligence and executive functioning. Neurological outcomes after TBI correlate to development of cerebral edema, which affect survival rates after TBI. It has been shown that myosin light-chain kinase (MLCK) increases cerebral edema and that pretreatment with an MLCK inhibitor (ML-7) reduces cerebral edema. The aim of this study was to determine whether inhibition of MLCK after TBI in postnatal day 24 (PND-24) mice would prevent breakdown of the blood-brain barrier (BBB) and development of cerebral edema and improve neurological outcome. We used a closed head injury model of TBI. ML-7 or saline treatment was administered at 4 h and every 24 h until sacrifice or 5 days after TBI. Mice were sacrificed at 24 h, 48 h, and 72 h and 7 days after impact. Mice treated with ML-7 after TBI had decreased levels of MLCK-expressing cells (20.7±4.8 vs. 149.3±40.6), less albumin extravasation (28.3±11.2 vs. 116.2±60.7 mm(2)) into surrounding parenchymal tissue, less Evans Blue extravasation (339±314 vs. 4017±560 ng/g), and showed a significant difference in wet/dry weight ratio (1.9±0.07 vs. 2.2±0.05 g), compared to saline-treated groups. Treatment with ML-7 also resulted in preserved neurological function measured by the wire hang test (57 vs. 21 sec) and two-object novel recognition test (old vs. new, 10.5 touches). We concluded that inhibition of MLCK reduces cerebral edema and preserves neurological function in PND-24 mice.
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Affiliation(s)
- Janet L Rossi
- 1 Neuroscience Center of Excellence, Louisiana State University Health Sciences Center , New Orleans, Louisiana
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20
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Curry FRE, Adamson RH. Tonic regulation of vascular permeability. Acta Physiol (Oxf) 2013; 207:628-49. [PMID: 23374222 PMCID: PMC4054936 DOI: 10.1111/apha.12076] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/10/2013] [Accepted: 01/28/2013] [Indexed: 12/30/2022]
Abstract
Our major theme is that the layered structure of the endothelial barrier requires continuous activation of signalling pathways regulated by sphingosine-1-phosphate (S1P) and intracellular cAMP. These pathways modulate the adherens junction, continuity of tight junction strands, and the balance of synthesis and degradation of glycocalyx components. We evaluate recent evidence that baseline permeability is maintained by constant activity of mechanisms involving the small GTPases Rap1 and Rac1. In the basal state, the barrier is compromised when activities of the small GTPases are reduced by low S1P supply or delivery. With inflammatory stimulus, increased permeability can be understood in part as the action of signalling to reduce Rap1 and Rac1 activation. With the hypothesis that microvessel permeability and selectivity under both normal and inflammatory conditions are regulated by mechanisms that are continuously active, it follows that when S1P or intracellular cAMP are elevated at the time of inflammatory stimulus, they can buffer changes induced by inflammatory agents and maintain normal barrier stability. When endothelium is exposed to inflammatory conditions and subsequently exposed to elevated S1P or intracellular cAMP, the same processes restore the functional barrier by first re-establishing the adherens junction, then modulating tight junctions and glycocalyx. In more extreme inflammatory conditions, loss of the inhibitory actions of Rac1-dependent mechanisms may promote expression of more inflammatory endothelial phenotypes by contributing to the up-regulation of RhoA-dependent contractile mechanisms and the sustained loss of surface glycocalyx allowing access of inflammatory cells to the endothelium.
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Affiliation(s)
- F-R E Curry
- Department of Physiology & Membrane Biology, School of Medicine, University of California at Davis, Davis, CA 95616, USA.
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21
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Shinde AV, Motiani RK, Zhang X, Abdullaev IF, Adam AP, González-Cobos JC, Zhang W, Matrougui K, Vincent PA, Trebak M. STIM1 controls endothelial barrier function independently of Orai1 and Ca2+ entry. Sci Signal 2013; 6:ra18. [PMID: 23512989 DOI: 10.1126/scisignal.2003425] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Endothelial barrier function is critical for tissue fluid homeostasis, and its disruption contributes to various pathologies, including inflammation and sepsis. Thrombin is an endogenous agonist that impairs endothelial barrier function. We showed that the thrombin-induced decrease in transendothelial electric resistance of cultured human endothelial cells required the endoplasmic reticulum-localized, calcium-sensing protein stromal interacting molecule 1 (STIM1), but was independent of Ca2+ entry across the plasma membrane and the Ca2+ release-activated Ca2+ channel protein Orai1, which is the target of STIM1 in the store-operated calcium entry pathway. We found that STIM1 coupled the thrombin receptor to activation of the guanosine triphosphatase RhoA, stimulation of myosin light chain phosphorylation, formation of actin stress fibers, and loss of cell-cell adhesion. Thus, STIM1 functions in pathways that are dependent on and independent of Ca2+ entry.
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Affiliation(s)
- Arti V Shinde
- The Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA
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22
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Wang H, Zhu HQ, Wang F, Zhou Q, Gui SY, Wang Y. MicroRNA-1 prevents high-fat diet-induced endothelial permeability in apoE knock-out mice. Mol Cell Biochem 2013; 378:153-9. [PMID: 23467882 PMCID: PMC3634980 DOI: 10.1007/s11010-013-1606-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/23/2013] [Indexed: 11/28/2022]
Abstract
The development of atherosclerosis (AS) is a multifactorial process in which elevated plasma cholesterol levels play a central role. As a new class of players involved in AS, the regulation and function of microRNAs (miR) in response to AS remain poorly understood. This study analyzed the effects of miR-1 (antagomir and mimic) on endothelial permeability and myosin light chain kinase (MLCK) expression and activity in the artery wall of apoE knock-out mice after feeding them a high-cholesterol diet. Further, we tested to determine whether that effects are involved in ERK phosphorylation. Here, we show that a high-cholesterol diet induces a significant decrease of miR-1 expression. Histopathologic examination demonstrated that miR-1 antagomir enhances endothelial permeability induced by high cholesterol and miR-1 mimic attenuated endothelial barrier dysfunction. Consistent with endothelial permeability, Western blotting, qPCR, and γ-32P-ATP phosphate incorporation showed that MLCK expression and activity were further increased in miR-1 antagomir-treated mice and decreased in miR-1 mimic-treated mice compared with those of mice receiving control miR. Further mechanistic studies showed that high-cholesterol-induced extracellular signal regulated kinase (ERK) activation was enhanced by miR-1 antagomir and attenuated by miR-1 mimic. Collectively, those results indicate that miR-1 contributes to endothelial barrier function via mechanisms involving not only MLCK expression and activity but also ERK phosphorylation.
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Affiliation(s)
- Hua Wang
- Department of Oncology, The Affiliated Provincial Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
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23
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Role of non-muscle myosin light chain kinase in neutrophil-mediated intestinal barrier dysfunction during thermal injury. Shock 2013; 38:436-43. [PMID: 22814287 DOI: 10.1097/shk.0b013e318268c731] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neutrophils and non-muscle myosin light chain kinase (nmMLCK) have been implicated in intestinal microvascular leakage and mucosal hyperpermeability in inflammation and trauma. The aim of this study was to characterize the role of nmMLCK in neutrophil-dependent gut barrier dysfunction following thermal injury, a common form of trauma that typically induces inflammation in multiple organs. Histopathological examination of the small intestine in mice after a full-thickness burn revealed morphological evidence of mucosa inflammation characterized by neutrophil infiltration into the lamina propria, epithelial contraction, and narrow villi with blunt brush borders and loss of goblet cells. Compared with their wild-type counterparts, nmMLCK mice displayed diminished morphological abnormalities. Likewise, intravital microscopic studies showed significant leukocyte adhesion in intestinal microvessels after burn, a response that was blunted in the absence of nmMLCK. Functionally, thermal injury significantly increased the gut lumen-to-blood transport of fluorescein isothiocyanate-dextran (4 kd), and this hyperpermeability was attenuated by either neutrophil depletion or nmMLCK deficiency. Consistent with the in vivo observations, in vitro assays with Caco-2 epithelial cell monolayers revealed a decrease in transcellular electric resistance coupled with myosin light chain phosphorylation, actomyosin ring condensation, and claudin-1 internalization upon stimulation with fMLP (N-formyl-methionyl-leucyl-phenylalanine)-activated neutrophils. Pretreatment of the cells with the MLCK inhibitor ML-7 prevented the tight junction responses. Taken together, the results suggest that nmMLCK plays an important role in neutrophil-dependent intestinal barrier dysfunction during inflammatory injury.
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24
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Yao H, Duan M, Yang L, Buch S. Nonmuscle myosin light-chain kinase mediates microglial migration induced by HIV Tat: involvement of β1 integrins. FASEB J 2013; 27:1532-48. [PMID: 23292072 DOI: 10.1096/fj.12-219600] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
One of the hallmark features of HIV-associated neurological disease is increased activation and migration of microglia. HIV transactivator of transcription (Tat) is released from infected cells and has the ability to recruit microglia. The purpose of this study was to investigate molecular mechanisms by which recombinant Tat₁₋₇₂, but not heated-inactive Tat₁₋₇₂,induces migration of rat primary microglia. Using primary microglia in Boyden chambers, we demonstrated the role of nonmuscle myosin light-chain kinase (nmMYLK) in Tat₁₋₇₂ (14.4 nM)-mediated increased microglial migration (up to 171.85%). These findings were validated using microglia isolated from wild-type (WT) or nmMYLK(-/-) mice in Dunn chamber assays. Tat₁₋₇₂-mediated activation of nmMYLK resulted in "inside-out" activation of β1 integrin, followed by "outside-in" activation of c-Src, Pyk2, and Cdc42-GTP (using G-LISA in primary and nmMYLK(-/-) microglia) and, subsequently, actin polymerization (flow cytometry and Western blot assays). In vivo corroboration of these findings demonstrated decreased migration of nmMYLK(-/-) microglia (2 × 10(5) cells transplanted into corpus callosum) compared with WT microglia toward microinjected Tat₁₋₇₂ (2 μg/mouse) in hippocampus. Up-regulation of nmMYLK in microglia was also detected in sections of basal ganglia from humans with HIV-encephalitis compared with uninfected controls. nmMYLK is thus critical for eliciting microglial migration during the innate immune response.
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Affiliation(s)
- Honghong Yao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198-5880, USA
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25
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Cunningham KE, Turner JR. Myosin light chain kinase: pulling the strings of epithelial tight junction function. Ann N Y Acad Sci 2012; 1258:34-42. [PMID: 22731713 DOI: 10.1111/j.1749-6632.2012.06526.x] [Citation(s) in RCA: 232] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dynamic regulation of paracellular permeability is essential for physiological epithelial function, while dysregulated permeability is common in disease. The recent elucidation of the molecular composition of the epithelial tight junction complex has been accompanied by characterization of diverse intracellular mediators of paracellular permeabiltiy. Myosin light chain kinase (MLCK), which induces contraction of the perijunctional actomyosin ring through myosin II regulatory light chain phosphorylation, has emerged as a key regulator of tight junction permeability. Examination of the regulation and role of MLCK in tight junction dysfunction has helped to define pathological processes and characterize the role of barrier loss in disease pathogenesis, and may provide future therapeutic targets to treat intestinal disease.
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26
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Rigor RR, Shen Q, Pivetti CD, Wu MH, Yuan SY. Myosin light chain kinase signaling in endothelial barrier dysfunction. Med Res Rev 2012; 33:911-33. [PMID: 22886693 DOI: 10.1002/med.21270] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Microvascular barrier dysfunction is a serious problem that occurs in many inflammatory conditions, including sepsis, trauma, ischemia-reperfusion injury, cardiovascular disease, and diabetes. Barrier dysfunction permits extravasation of serum components into the surrounding tissue, leading to edema formation and organ failure. The basis for microvascular barrier dysfunction is hyperpermeability at endothelial cell-cell junctions. Endothelial hyperpermeability is increased by actomyosin contractile activity in response to phosphorylation of myosin light chain by myosin light chain kinase (MLCK). MLCK-dependent endothelial hyperpermeability occurs in response to inflammatory mediators (e.g., activated neutrophils, thrombin, histamine, tumor necrosis factor alpha, etc.), through multiple cell signaling pathways and signaling molecules (e.g., Ca(++) , protein kinase C, Src kinase, nitric oxide synthase, etc.). Other signaling molecules protect against MLCK-dependent hyperpermeability (e.g., sphingosine-1-phosphate or cAMP). In addition, individual MLCK isoforms play specific roles in endothelial barrier dysfunction, suggesting that isoform-specific inhibitors could be useful for treating inflammatory disorders and preventing multiple organ failure. Because endothelial barrier dysfunction depends upon signaling through MLCK in many instances, MLCK-dependent signaling comprises multiple potential therapeutic targets for preventing edema formation and multiple organ failure. The following review is a discussion of MLCK-dependent mechanisms and cell signaling events that mediate endothelial hyperpermeability.
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Affiliation(s)
- Robert R Rigor
- Department of Surgery, University of California at Davis School of Medicine, Sacramento, California, USA
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27
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Yuan SY, Shen Q, Rigor RR, Wu MH. Neutrophil transmigration, focal adhesion kinase and endothelial barrier function. Microvasc Res 2011; 83:82-8. [PMID: 21864543 DOI: 10.1016/j.mvr.2011.06.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 06/20/2011] [Accepted: 06/29/2011] [Indexed: 11/30/2022]
Abstract
Neutrophil activation is an essential component of innate immune defense against infection and injury. In response to inflammatory stimulation, circulating neutrophils undergo a series of dynamic and metabolic changes characterized by β2-intergrin mediated adhesion to microvascular endothelium and subsequent transendothelial migration. During this process, neutrophils release granular contents containing digestive enzymes and produce cytotoxic agents such as reactive oxygen species and cytokines. These products target endothelial barriers inducing phosphorylation-triggered junction dissociation, actin stress fiber formation, and actomyosin contraction, manifest as paracellular hyperpermeability. Endothelial cell-matrix focal adhesions play an integral role in this process by providing structural support for endothelial conformational changes that facilitate neutrophil transmigration, as well as by recruiting intracellular molecules that constitute the hyperpermeability signaling cascades. As a central connector of the complex signaling network, focal adhesion kinase (FAK) is activated following neutrophil adhesion, and further mediates the reorganization of endothelial integrin-matrix attachments in a pattern coordinating with cytoskeleton contraction and junction opening. In this review, we present recent experimental evidence supporting the importance of FAK in neutrophil-dependent regulation of endothelial permeability. The discussion focuses on the mechanisms by which neutrophils activate FAK and its downstream effects on endothelial barriers.
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Affiliation(s)
- Sarah Y Yuan
- Division of Research, Department of Surgery, University of California at Davis School of Medicine, Sacramento, CA 95817, USA
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Hong F, Haldeman BD, Jackson D, Carter M, Baker JE, Cremo CR. Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011. [PMID: 21565153 DOI: 10.1016/j.abb.2011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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Affiliation(s)
- Feng Hong
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, 89557, USA
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Sun C, Wu MH, Yuan SY. Nonmuscle myosin light-chain kinase deficiency attenuates atherosclerosis in apolipoprotein E-deficient mice via reduced endothelial barrier dysfunction and monocyte migration. Circulation 2011; 124:48-57. [PMID: 21670231 DOI: 10.1161/circulationaha.110.988915] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Endothelial dysfunction and monocyte migration are key events in the pathogenesis of atherosclerosis. Nonmuscle myosin light-chain kinase (nmMLCK), the predominant MLCK isoform in endothelial cells, has been shown to contribute to vascular inflammation by altering endothelial barrier function. However, its impact on atherogenesis remains unknown. METHODS AND RESULTS We investigated the role of nmMLCK in the development of atherosclerotic lesions in apolipoprotein E-deficient (apoE(-/-)) mice fed an atherogenic diet for 12 weeks. Histopathological examination demonstrated that nmMLCK deficiency (apoE(-/-)nmmlck(-/-)) reduced the size of aortic lesions by 53%, lipid contents by 44%, and macrophage deposition by 40%. Western blotting and reverse-transcription polymerase chain reaction revealed the expression of nmMLCK in aortic endothelial cells and peripheral blood monocytes. Measurements of transendothelial electric resistance indicated that nmMLCK deficiency attenuated endothelial barrier dysfunction caused by thrombin, oxidized low-density lipoprotein, and tumor necrosis factor α. In monocytes, nmMLCK deficiency reduced their migration in response to the chemokine monocyte chemoattractant protein-1. Further mechanistic studies showed that nmMLCK acted through both myosin light chain phosphorylation-coupled and -uncoupled pathways; the latter involved Rous sacracoma virus homolog genes-encoded tyrosine kinases (Src) signaling. Moreover, depletion of Src via gene silencing, site-specific mutagenesis, or pharmacological inhibition of Src greatly attenuated nmMLCK-dependent endothelial barrier dysfunction and monocyte migration. CONCLUSIONS Nonmuscle myosin light-chain kinase contributes to atherosclerosis by regulating endothelial barrier function and monocyte migration via mechanisms involving not only kinase-mediated MLC phosphorylation but also Src activation.
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Affiliation(s)
- Chongxiu Sun
- Department of Surgery, University of California Davis School of Medicine, 4625 2nd Ave, Room 3005, Sacramento, CA 95817, USA
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Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011; 510:135-46. [PMID: 21565153 DOI: 10.1016/j.abb.2011.04.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/22/2011] [Accepted: 04/25/2011] [Indexed: 11/23/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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Rossi JL, Ralay Ranaivo H, Patel F, Chrzaszcz M, Venkatesan C, Wainwright MS. Albumin causes increased myosin light chain kinase expression in astrocytes via p38 mitogen-activated protein kinase. J Neurosci Res 2011; 89:852-61. [PMID: 21360574 DOI: 10.1002/jnr.22600] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 12/30/2022]
Abstract
Myosin light chain kinase (MLCK) plays an important role in the reorganization of the cytoskeleton, leading to disruption of vascular barrier integrity in multiple organs, including the blood-brain barrier (BBB), after traumatic brain injury (TBI). MLCK has been linked to transforming growth factor (TGF) and rho kinase signaling pathways, but the mechanisms regulating MLCK expression following TBI are not well understood. Albumin leaks into the brain parenchyma following TBI, activates glia, and has been linked to TGF-β receptor signaling. We investigated the role of albumin in the increase of MLCK in astrocytes and the signaling pathways involved in this increase. After midline closed-skull TBI in mice, there was a significant increase in MLCK-immunoreactive (IR) cells and albumin extravasation, which was prevented by treatment with the MLCK inhibitor ML-7. Using immunohistochemical methods, we identified the MLCK-IR cells as astrocytes. In primary astrocytes, exposure to albumin increased both isoforms of MLCK, 130 and 210. Inhibition of the TGF-β receptor partially prevented the albumin-induced increase in both isoforms, which was not prevented by inhibition of smad3. Inhibition of p38 MAPK, but not ERK, JNK, or rho kinase, also prevented this increase. These results are further evidence of a role of MLCK in the mechanisms of BBB compromise following TBI and identify astrocytes as a cell type, in addition to endothelium in the BBB, that expresses MLCK. These findings implicate albumin, acting through p38 MAPK, in a novel mechanism by which activation of MLCK following TBI may lead to compromise of the BBB.
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Affiliation(s)
- Janet L Rossi
- Department of Pediatrics, Divisions of Critical Care, Children's Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA
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p38 MAP kinase mediates burn serum-induced endothelial barrier dysfunction: involvement of F-actin rearrangement and L-caldesmon phosphorylation. Shock 2011; 34:222-8. [PMID: 20160665 DOI: 10.1097/shk.0b013e3181d75a66] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aim of this study was to test the hypothesis that circulating factors released after a severe burn cause endothelial barrier dysfunction by triggering endothelial cell (EC) contraction through a p38 mitogen-activated protein (MAP) kinase-dependent mechanism. Human umbilical vein ECs (ECV304 cell line) were cultured to create a monolayer of cells that were then cultured with 20% human normal or burn serum. Monolayer permeability was measured by the influx of labeled albumin across the cells. Endothelial cells contraction was determined by alterations of cell surface area and formation of intracellular gaps. P38 MAP kinase activation, F-actin arrangement, and L-caldesmon phosphorylation were assessed by Western blots or immunofluorescence staining. These studies showed that exposure to burn serum resulted in a significant increase in endothelial permeability in a time-dependent manner, which was paralleled by a rapid and persistent activation of p38 MAP kinases. Morphologically, increased intercellular gaps, reduced cell surface area, and a unique rearrangement of F-actin cytoskeleton were observed in burn serum-treated ECs. Inhibition of p38 MAP kinase suppressed the rearrangement of F-actin cytoskeleton, reduced the occurrence of burn serum-induced formation of intercellular gaps, and ameliorated endothelial hyperpermeability. Further study showed that phosphorylation of L-caldesmon was enhanced in burn serum-treated cells via p38 MAP kinase; overexpression of L-caldesmon by adenovirus transfection, however, attenuated the increase in endothelial permeability by burn serum challenge. Collectively, these results have demonstrated for the first time that p38 MAP kinase is an important participant in mediating burn serum-induced endothelial barrier dysfunction through rearrangement of the F-actin cytoskeleton and phosphorylation of L-caldesmon. Inhibition of p38 MAP kinase in vivo, thus, would be a promising therapeutic strategy in ameliorating burn shock development.
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Shen Q, Rigor RR, Pivetti CD, Wu MH, Yuan SY. Myosin light chain kinase in microvascular endothelial barrier function. Cardiovasc Res 2010; 87:272-80. [PMID: 20479130 DOI: 10.1093/cvr/cvq144] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Microvascular barrier dysfunction is implicated in the initiation and progression of inflammation, posttraumatic complications, sepsis, ischaemia-reperfusion injury, atherosclerosis, and diabetes. Under physiological conditions, a precise equilibrium between endothelial cell-cell adhesion and actin-myosin-based centripetal tension tightly controls the semi-permeability of microvascular barriers. Myosin light chain kinase (MLCK) plays an important role in maintaining the equilibrium by phosphorylating myosin light chain (MLC), thereby inducing actomyosin contractility and weakening endothelial cell-cell adhesion. MLCK is activated by numerous physiological factors and inflammatory or angiogenic mediators, causing vascular hyperpermeability. In this review, we discuss experimental evidence supporting the crucial role of MLCK in the hyperpermeability response to key cell signalling events during inflammation. At the cellular level, in vitro studies of cultured endothelial monolayers treated with MLCK inhibitors or transfected with specific inhibiting peptides have demonstrated that induction of endothelial MLCK activity is necessary for hyperpermeability. Ex vivo studies of live microvessels, enabled by development of the isolated, perfused venule method, support the importance of MLCK in endothelial permeability regulation in an environment that more closely resembles in vivo tissues. Finally, the role of MLCK in vascular hyperpermeability has been confirmed with in vivo studies of animal disease models and the use of transgenic MLCK210 knockout mice. These approaches provide a more complete view of the role of MLCK in vascular barrier dysfunction.
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Affiliation(s)
- Qiang Shen
- Division of Research, Department of Surgery, University of California at Davis School of Medicine, 4625 2nd Avenue, Sacramento, CA 95817, USA
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Kremer T, Hernekamp F, Riedel K, Peter C, Gebhardt M, Germann G, Heitmann C, Walther A. Topical application of cerium nitrate prevents burn edema after burn plasma transfer. Microvasc Res 2009; 78:425-31. [DOI: 10.1016/j.mvr.2009.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 07/28/2009] [Accepted: 07/29/2009] [Indexed: 10/20/2022]
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Chico LK, Van Eldik LJ, Watterson DM. Targeting protein kinases in central nervous system disorders. Nat Rev Drug Discov 2009; 8:892-909. [PMID: 19876042 PMCID: PMC2825114 DOI: 10.1038/nrd2999] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Protein kinases are a growing drug target class in disorders in peripheral tissues, but the development of kinase-targeted therapies for central nervous system (CNS) diseases remains a challenge, largely owing to issues associated specifically with CNS drug discovery. However, several candidate therapeutics that target CNS protein kinases are now in various stages of preclinical and clinical development. We review candidate compounds and discuss selected CNS protein kinases that are emerging as important therapeutic targets. In addition, we analyse trends in small-molecule properties that correlate with key challenges in CNS drug discovery, such as blood-brain barrier penetrance and cytochrome P450-mediated metabolism, and discuss the potential of future approaches that will integrate molecular-fragment expansion with pharmacoinformatics to address these challenges.
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Affiliation(s)
- Laura K Chico
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Chicago, Illinois 60611, USA
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Shen Q, Wu MH, Yuan SY. Endothelial contractile cytoskeleton and microvascular permeability. ACTA ACUST UNITED AC 2009; 2009:43-50. [PMID: 20871798 DOI: 10.2147/chc.s5118] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Microvascular barrier dysfunction represents a significant problem in clinical conditions associated with trauma, burn, sepsis, acute respiratory distress syndrome, ischemia-reperfusion injury, and diabetic retinopathy. An important cellular mechanism underlying microvascular leakage is the generation of contractile force from the endothelial cytoskeleton, which counteracts cell-cell and cell-matrix adhesions leading to paracellular hyperpermeability. In this review, we present recent experimental evidence supporting the critical role of MLCK-activated, RhoA/ROCK-regulated contractile cytoskeleton in endothelial permeability response to inflammatory and thrombotic stimuli arising from thermal injury, activated neutrophils, vascular endothelial growth factor, and fibrinogen degradation products. Further understanding the molecular basis of microvascular barrier structure and function would contribute to the development of novel therapeutic targets for treating circulatory disorders and vascular injury.
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Affiliation(s)
- Qiang Shen
- Division of Research, Department, of Surgery, University of California, at Davis School of Medicine, Sacramento, CA, USA
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Internalization of eNOS and NO delivery to subcellular targets determine agonist-induced hyperpermeability. Proc Natl Acad Sci U S A 2009; 106:6849-53. [PMID: 19342481 DOI: 10.1073/pnas.0812694106] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanisms of endothelial nitric oxide synthase (eNOS) regulation of microvascular permeability remain unresolved. Agonist-induced internalization may have a role in this process. We demonstrate here that internalization of eNOS is required to deliver NO to subcellular locations to increase endothelial monolayer permeability to macromolecules. Using dominant-negative mutants of dynamin-2 (dyn2K44A) and caveolin-1 (cav1Y14F), we show that anchoring eNOS-containing caveolae to plasma membrane inhibits hyperpermeability induced by platelet-activating factor (PAF), VEGF in ECV-CD8eNOSGFP (ECV-304 transfected cells) and postcapillary venular endothelial cells (CVEC). We also observed that anchoring caveolar eNOS to the plasma membrane uncouples eNOS phosphorylation at Ser-1177 from NO production. This dissociation occurred in a mutant- and cell-dependent way. PAF induced Ser-1177-eNOS phosphorylation in ECV-CD8eNOSGFP and CVEC transfected with dyn2K44A, but it dephosphorylated eNOS at Ser-1177 in CVEC transfected with cav1Y14F. Interestingly, dyn2K44A eliminated NO production, whereas cav1Y14F caused reduction in NO production in CVEC. NO production by cav1Y14F-transfected CVEC occurred in caveolae bound to the plasma membrane, and was ineffective in causing an increase in permeability. Our study demonstrates that eNOS internalization is required for agonist-induced hyperpermeability, and suggests that a mechanism by which eNOS is activated by phosphorylation at the plasma membrane and its endocytosis is required to deliver NO to subcellular targets to cause hyperpermeability.
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Guo M, Daines D, Tang J, Shen Q, Perrin RM, Takada Y, Yuan SY, Wu MH. Fibrinogen-gamma C-terminal fragments induce endothelial barrier dysfunction and microvascular leak via integrin-mediated and RhoA-dependent mechanism. Arterioscler Thromb Vasc Biol 2009; 29:394-400. [PMID: 19122172 DOI: 10.1161/atvbaha.108.180950] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES The purposes of this study were to characterize the direct effect of the C-terminal fragment of fibrinogen gamma chain (gammaC) on microvascular endothelial permeability and to examine its molecular mechanism of action. METHODS AND RESULTS Intravital microscopy was performed to measure albumin extravasation in intact mesenteric microvasculature, followed by quantification of hydraulic conductivity in single perfused microvessels. Transendothelial electric resistance was measured in microvascular endothelial cells in combination with immunoblotting and immunocytochemistry. The results show that gammaC induced time- and concentration-dependent increases in protein transvascular flux and water permeability and decreases in endothelial barrier function, coupled with Rho GTPase activation, myosin light chain phosphorylation, and stress fiber formation. Depletion of RhoA via siRNA knockdown or pharmacological inhibition of RhoA signaling attenuated gammaC-induced barrier dysfunction. Imaging analyses demonstrated binding of gammaC to endothelial cells; the interaction was inhibited during blockage of the alphavbeta3 integrin. Furthermore, in vivo experiments showed that the microvascular leak response to gammaC was attenuated in integrin beta3(-/-) animals. CONCLUSION Fibrinogen-gamma C terminus directly interacts with the microvascular endothelium causing fluid and protein leak. The endothelial response to gammaC involves an integrin receptor-mediated RhoA-dependent signaling pathway that leads to paracellular hyperpermeability.
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Affiliation(s)
- Mingzhang Guo
- Division of Research, Department of Surgery, University of California Davis School of Medicine, Sacramento, CA 95817, USA
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Breslin JW, Wu MH, Guo M, Reynoso R, Yuan SY. Toll-like receptor 4 contributes to microvascular inflammation and barrier dysfunction in thermal injury. Shock 2008; 29:349-55. [PMID: 17704733 DOI: 10.1097/shk.0b013e3181454975] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Systemic and microvascular inflammation plays a key role in the development of multiple organ failure after infection, sepsis, and traumatic injury. Toll-like receptors (TLRs) regulate host responses to pathogens and sterile, injury-associated inflammatory responses. We investigated whether TLR-4 contributes to microvascular dysfunction during thermal injury in vivo in anesthetized wild-type or TLR-4 (-/-) mice receiving either a 25% total body surface area full-thickness scald burn or sham treatment on the dorsal skin. Using intravital microscopy, we assessed the hemodynamics and leukocyte dynamics in the mesenteric microvasculature as representative of the splanchnic microcirculation at a site remote from the burn wound. The transvascular flux of fluorescein isothiocyanate-albumin across mesenteric venules was measured as an indicator of microvascular permeability. Furthermore, cultured microvascular endothelial cell models were used to evaluate the endothelial-specific mechanisms involved in TLR-4-mediated barrier dysfunction. The results showed significantly elevated microvascular permeability in wild-type mice after burn, whereas this response was markedly attenuated in TLR-4 (-/-) mice. Burn injury also increased leukocyte adhesion in mesenteric venules of wild-type mice, and a blunted leukocyte response was seen in the TLR-4 mice. Treatment of endothelial cell monolayers with burn plasma induced a rapid reduction in the transendothelial electrical resistance measured by electric cell-substrate impedance sensing, indicative of endothelial cell-cell adhesive barrier dysfunction. Reducing expression of TLR-4 with siRNA treatment attenuated this response. Taken together, these data indicate that TLR-4 plays an important role in microvascular leakage and leukocyte adhesion under the inflammatory condition associated with nonseptic thermal injury.
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Affiliation(s)
- Jerome W Breslin
- Department of Surgery Division of Research, University of California Davis School of Medicine, Sacramento, California 95817, USA.
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WHAT'S NEW IN SHOCK, NOVEMBER 2007? Shock 2007. [DOI: 10.1097/shk.0b013e3181572aad] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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