We acknowledge the initiation and support of this Research Topic by the International Union of Immunological Societies (IUIS). We hereby state publicly that the IUIS has had no editorial input in articles included in this Research Topic, thus ensuring that all aspects of this Research Topic are evaluated objectively, unbiased by any specific policy or opinion of the IUIS.

The endothelium, a monolayer of endothelial cells, constitutes the inner cellular lining of the blood vessels (arteries, veins and capillaries) and the lymphatic system, and therefore is in direct contact with the blood/lymph and the circulating cells. The endothelium is a major player in the control of blood fluidity, platelet aggregation and vascular tone, a major actor in the regulation of immunology, inflammation and angiogenesis, and an important metabolizing and an endocrine organ. Endothelial cells controls vascular tone, and thereby blood flow, by synthesizing and releasing relaxing and contracting factors such as nitric oxide, metabolites of arachidonic acid via the cyclooxygenases, lipoxygenases and cytochrome P450 pathways, various peptides (endothelin, urotensin, CNP, adrenomedullin, etc.), adenosine, purines, reactive oxygen species and so on. Additionally, endothelial ectoenzymes are required steps in the generation of vasoactive hormones such as angiotensin II. An endothelial dysfunction linked to an imbalance in the synthesis and/or the release of these various endothelial factors may explain the initiation of cardiovascular pathologies (from hypertension to atherosclerosis) or their development and perpetuation. Table of Contents: Introduction / Multiple Functions of the Endothelial Cells / Calcium Signaling in Vascular Cells and Cell-to-Cell Communications / Endothelium-Dependent Regulation of Vascular Tone / Conclusion / References

Arrest chemokines are a small group of chemokines that promote leukocyte arrest from rolling by triggering rapid integrin activation. Arrest chemokines have been described for neutrophils, monocytes, eosinophils, naïve lymphocytes and effector memory T cells. Most arrest chemokines are immobilized on the endothelial surface by binding to heparin sulfate proteoglycans. Whether soluble chemokines can promote integrin activation and arrest is controversial (Alon-Gerszten). Many aspects of the signaling pathway from the GPCR chemokine receptor to integrin activation are the subject of active investigation. Leukocyte adhesion deficiency III is a human disease in which chemokine-triggered integrin activation is defective because of a mutation in the cytoskeletal protein kindlin-3. About 10 different such mutations have been described. The defects seen in patients with LAD-III elucidate the importance of rapid integrin activation for host defense in humans. We welcome reports that help clarifying this crucial first step in the process of leukocyte transendothelial migration.

This book provides a comprehensive review of the structure, function and pathophysiology of the pulmonary vasculature. Emerging evidence reveals the multifaceted roles played by the pulmonary vasculature. To reflect those roles, the individual chapters address topics ranging from pulmonary blood vessel development to vascular endothelial apoptosis, and delve deeply into our current understanding of various aspects of the pulmonary vasculature.

The third book in the group devoted to the "natural" immune system, this volume provides the ideal detailed, up-to-date overview of neutrophil function. Distilling new information alongside observations of the past, the book focuses on some of the most critical developments in currentneutrophil research. Specific examples of diseases resulting from neutrophil dysfunction and deficiency are brought to life by clinical case studies. An essential source of current research into this exciting field, this volume will be invaluable for advanced students and researchers in immunology,cell biology, and medicine.

The skin, the body’s largest organ, is strategically located at the interface with the external environment where it detects, integrates and responds to a diverse range of stressors, including solar radiation. It has already been established that the skin is an important peripheral neuroendocrine-immune organ that is closely networked with central regulatory systems. These capabilities contribute to the maintenance of peripheral homeostasis. Specifically, epidermal and dermal cells produce and respond to classical stress neurotransmitters, neuropeptides and hormones, production which is stimulated by ultraviolet radiation (UVR), biological factors (infectious and non-infectious) and other physical and chemical agents. Examples of local biologically active products are cytokines, biogenic amines (catecholamines, histamine, serotonin and N-acetyl-serotonin), melatonin, acetylocholine, neuropeptides including pituitary (proopiomelanocortin-derived ACTH, b-endorphin or MSH peptides, thyroid stimulating hormone) and hypothalamic (corticotropin-releasing factor and related urocortins, thyroid-releasing hormone) hormones, as well as enkephalins and dynorphins, thyroid hormones, steroids (glucocorticoids, mineralocorticoids, sex hormones, 7-δ steroids), secosteroids, opioids and endocannabinoids. The production of these molecules is hierarchical, organized along the algorithms of classical neuroendocrine axes such as the hypothalamic pituitary adrenal axis (HPA), hypothalamic-thyroid axis (HPT), serotoninergic, melatoninergic, catecholaminergic, cholinergic, steroid/secosteroidogenic, opioid and endocannabinoid systems. Disruptions of these axes or of communication between them may lead to skin and/or systemic diseases. These local neuroendocrine networks also serve to limit the effect of noxious environmental agents to preserve local and consequently global homeostasis. Moreover, the skin-derived factors/systems can also activate cutaneous nerve endings to alert the brain to changes in the epidermal or dermal environments, or alternatively to activate other coordinating centers by direct (spinal cord) neurotransmission without brain involvement. Furthermore, rapid and reciprocal communications between epidermal and dermal and adnexal compartments are also mediated by neurotransmission including antidromic modes of conduction. Lastly, skin cells and the skin as an organ coordinate and/or regulate not only peripheral but also global homeostasis.