In electrically nonexcitable cells, Ca2+ influx is essential for regulating a host of kinetically distinct processes involving exocytosis, enzyme control, gene regulation, cell growth and prolifera...

Store-operated calcium channels.

The microvascular endothelial cell monolayer localized at the critical interface between the blood and vessel wall has the vital functions of regulating tissue fluid balance and supplying the essential nutrients needed for the survival of the organism. The endothelial cell is an exquisite "sensor" that responds to diverse signals generated in the blood, subendothelium, and interacting cells. The endothelial cell is able to dynamically regulate its paracellular and transcellular pathways for transport of plasma proteins, solutes, and liquid. The semipermeable characteristic of the endothelium (which distinguishes it from the epithelium) is crucial for establishing the transendothelial protein gradient (the colloid osmotic gradient) required for tissue fluid homeostasis. Interendothelial junctions comprise a complex array of proteins in series with the extracellular matrix constituents and serve to limit the transport of albumin and other plasma proteins by the paracellular pathway. This pathway is highly regulated by the activation of specific extrinsic and intrinsic signaling pathways. Recent evidence has also highlighted the importance of the heretofore enigmatic transcellular pathway in mediating albumin transport via transcytosis. Caveolae, the vesicular carriers filled with receptor-bound and unbound free solutes, have been shown to shuttle between the vascular and extravascular spaces depositing their contents outside the cell. This review summarizes and analyzes the recent data from genetic, physiological, cellular, and morphological studies that have addressed the signaling mechanisms involved in the regulation of both the paracellular and transcellular transport pathways.

https://www.physiology.org/doi/pdf/10.1152/physrev.00012.2005

Signaling Mechanisms Regulating Endothelial Permeability

Acute lung injury in humans is characterized histopathologically by neutrophilic alveolitis, injury of the alveolar epithelium and endothelium, hyaline membrane formation, and microvascular thrombi. Different animal models of experimental lung injury have been used to investigate mechanisms of lung injury. Most are based on reproducing in animals known risk factors for ARDS, such as sepsis, lipid embolism secondary to bone fracture, acid aspiration, ischemia-reperfusion of pulmonary or distal vascular beds, and other clinical risks. However, none of these models fully reproduces the features of human lung injury. The goal of this review is to summarize the strengths and weaknesses of existing models of lung injury. We review the specific features of human ARDS that should be modeled in experimental lung injury and then discuss specific characteristics of animal species that may affect the pulmonary host response to noxious stimuli. We emphasize those models of lung injury that are based on reproducing risk factors for human ARDS in animals and discuss the advantages and disadvantages of each model and the extent to which each model reproduces human ARDS. The present review will help guide investigators in the design and interpretation of animal studies of acute lung injury.

Animal models of acute lung injury.

Endothelial cells, which form the inner cellular lining of blood vessels and lymphatics, display remarkable heterogeneity in structure and function. This is the first of a 2-part review focused on phenotypic heterogeneity of blood vessel endothelium. This review provides an historical perspective of our understanding of endothelial heterogeneity, discusses the scope of phenotypic diversity across the vascular tree, and addresses proximate and evolutionary mechanisms of endothelial cell heterogeneity. The overall goal is to underscore the importance of phenotypic heterogeneity as a core property of the endothelium.

Phenotypic Heterogeneity of the Endothelium: I. Structure, Function, and Mechanisms

Endothelial cells, which form the inner cellular lining of blood vessels and lymphatics, display remarkable heterogeneity in structure and function. This is the second of a 2-part review on the phenotypic heterogeneity of blood vessel endothelial cells. The first part discusses the scope, the underlying mechanisms, and the diagnostic and therapeutic implications of phenotypic heterogeneity. Here, these principles are applied to an understanding of organ-specific phenotypes in representative vascular beds including arteries and veins, heart, lung, liver, and kidney. The goal is to underscore the importance of site-specific properties of the endothelium in mediating homeostasis and focal vascular pathology, while at the same time emphasizing the value of approaching the endothelium as an integrated system.

/pdf/phenotypic-heterogeneity-of-the-endothelium-ii-4bmhmf3l34.pdf

Phenotypic Heterogeneity of the Endothelium II. Representative Vascular Beds

SPECIFIC AIMTo determine whether host selenium (Se) deficiency can induce changes in the genome of a replicating influenza virus such that a normally mild virus converts into a more virulent strain and to characterize such genomic changes.PRINCIPAL FINDINGS1. Replication of a mild strain of influenza virus in Se-deficient mice results in a novel virulent strain that causes severe lung pathology even when passed into Se-adequate miceSe-deficient mice developed much more severe lung pathology postinfection with influenza virus than Se-adequate infected mice. To determine whether host factors or viral factors were responsible for the increased pathogenicity of influenza virus that had replicated in Se-deficient mice, a passage experiment was performed. We infected groups of Se-adequate and Se-deficient mice with influenza A/Bangkok/1/79 (H3N2). At 5 days postinfection, the mice were killed and virus was recovered from the lungs. Five separate isolates from each group of mice were used to inoculate five indiv...

/pdf/host-nutritional-selenium-status-as-a-driving-force-for-4slett99k1.pdf

Host nutritional selenium status as a driving force for influenza virus mutations.

Cytosolic Ca2+ concentration ([Ca2+]i) plays an important role in control of pulmonary vascular endothelial cell (ECs) barrier function. In this study, we investigated whether thapsigargin- and ion...

Pulmonary microvascular and macrovascular endothelial cells: differential regulation of Ca2+ and permeability.

Pulmonary endothelium forms a semiselective barrier that regulates fluid balance and leukocyte trafficking. During the course of lung inflammation, neurohumoral mediators and oxidants act on endoth...

Signal transduction and regulation of lung endothelial cell permeability. Interaction between calcium and cAMP

Activation of Ca2+ entry is known to produce endothelial cell shape change, leading to increased permeability, leukocyte migration, and initiation of angiogenesis in conduit-vessel endothelial cell...

Store-operated calcium entry promotes shape change in pulmonary endothelial cells expressing Trp1.

Leukocyte adherence to the endothelium after ischemia and reperfusion contributes to microvascular injury in most organs. The purpose of this study was to evaluate the leukocyte and endothelial cel...

Timothy Moore

Papers

Host nutritional selenium status as a driving force for influenza virus mutations.

Pulmonary microvascular and macrovascular endothelial cells: differential regulation of Ca2+ and permeability.

Signal transduction and regulation of lung endothelial cell permeability. Interaction between calcium and cAMP

Store-operated calcium entry promotes shape change in pulmonary endothelial cells expressing Trp1.

Adhesion molecules contribute to ischemia and reperfusion-induced injury in the isolated rat lung.