The Tight Junction And Its Proteins More Than Just A Barrier

For a long time, the tight junction (TJ) was known to form and regulate the paracellular barrier between epithelia and endothelial cell sheets. Starting shortly after the discovery of the proteins forming the TJ—mainly the two families of claudins and TAMPs—several other functions have been discovered, a striking one being the surprising finding that some claudins form paracellular channels for small ions and/or water. This Special Issue includes 43 articles covering numerous dedicated topics including pathogens affecting the TJ barrier, TJ regulation via immune cells, the TJ as a therapeutic target, TJ and cell polarity, function and regulation by proteins of the tricellular TJ, TJ as a regulator of cellular processes, organ- and tissue-specific functions, TJ as sensors and reacting to environmental conditions, and last but not least, TJ proteins and cancer.

For a long time, the tight junction (TJ) was known to form and regulate the paracellular barrier between epithelia and endothelial cell sheets. Starting shortly after the discovery of the proteins forming the TJ--mainly the two families of claudins and TAMPs--several other functions have been discovered, a striking one being the surprising finding that some claudins form paracellular channels for small ions and/or water. This Special Issue includes 43 articles covering numerous dedicated topics including pathogens affecting the TJ barrier, TJ regulation via immune cells, the TJ as a therapeutic target, TJ and cell polarity, function and regulation by proteins of the tricellular TJ, TJ as a regulator of cellular processes, organ- and tissue-specific functions, TJ as sensors and reacting to environmental conditions, and last but not least, TJ proteins and cancer.

Current Topics in Membranes

Tight junction proteins connect epithelial and endothelial cells and, importantly, form selective barriers and channels for paracellular transportation. Two types of tight junction proteins—the claudin family (claudins-1 to -27) and the TAMP family (occludin, Marvel-D2, and tricellulin)—can be distinguished molecularly and functionally. Recent work has focused on delineating the functional significance of differences in selective permeability, for example, by examining the regulatory mechanisms of tight junctions. This work is of great clinical importance as many inflammatory or infectious diseases are characterized by increased permeability and the manipulation of tight junctions presents a new horizon in the development of novel therapeutics. The volume Barriers and Channels Formed by Tight Junction Proteins II provides a detailed look at the recent advances in our understanding of tight junction regulation and dysregulation. The papers included focus on three major themes: inflammation and gastrointestinal function; epithelial transport, barrier modulation, and food components; and tight junctions in intestinal and renal epithelia. NOTE: Annals volumes are available for sale as individual books or as a journal. For more information on instutional journal subscriptions, please visit http://ordering.onlinelibrary.wiley.com/subs.asp?ref=1749-6632&doi=10.111/(ISSN)1749-6632 ACADEMY MEMBERS: Please contact the New York Academy of Sciences directly to place your order (www.nyas.org). Members of the New York Academy of Science receive full-text access to Annals online and discounts on print volumes. Please visit http://www.nyas.org/MemberCenter/Join.aspx for more information on becoming a member.

This volume explores the dynamic topic of tight junctions. The book focuses on tight junctions' role in sealing adjacent epithelial cells in a narrow band just beneath their apical surface. The book explains how tight junctions consist of a network of claudins and other proteins, and delves into how they hold cells together and form functional and protective barriers, regulating the passage of molecules and ions through the space between cells. The book opens with a discussion of the evolution of research on tight junctions, discussing a range of primary areas of growth, including the current knowledge on the particular physiological function of different claudins due to the development of an array of knock out mice. The chapters also explore in-depth studies of tight junctions in specific tissues (gut, lung and endothelia). This book offers a comprehensive understanding on post-translational modifications of occludin and its impact on tight junction function, as well as the molecular composition and function of tricellular tight junctions. This volume is particularly relevant to students and scientists in neuroscience, cell biology, physiology, cell differentiation, and cancer research.

This e-book will review special features of the cerebral circulation and how they contribute to the physiology of the brain. It describes structural and functional properties of the cerebral circulation that are unique to the brain, an organ with high metabolic demands and the need for tight water and ion homeostasis. Autoregulation is pronounced in the brain, with myogenic, metabolic and neurogenic mechanisms contributing to maintain relatively constant blood flow during both increases and decreases in pressure. In addition, unlike peripheral organs where the majority of vascular resistance resides in small arteries and arterioles, large extracranial and intracranial arteries contribute significantly to vascular resistance in the brain. The prominent role of large arteries in cerebrovascular resistance helps maintain blood flow and protect downstream vessels during changes in perfusion pressure. The cerebral endothelium is also unique in that its barrier properties are in some way more like epithelium than endothelium in the periphery. The cerebral endothelium, known as the blood-brain barrier, has specialized tight junctions that do not allow ions to pass freely and has very low hydraulic conductivity and transcellular transport. This special configuration modifies Starling's forces in the brain microcirculation such that ions retained in the vascular lumen oppose water movement due to hydrostatic pressure. Tight water regulation is necessary in the brain because it has limited capacity for expansion within the skull. Increased intracranial pressure due to vasogenic edema can cause severe neurologic complications and death.

Aim of this volume is to clarify the relationship between molecular structure and function of tight junction proteins, as well as their regulation and their role in diseases. Current research may form a basis for future diagnostic and therapeutic approaches to diseases which seem to have not much in common but are characterized by defects of organ barriers, like Crohn's disease, renal hypertension, inner ear deafness, and cancerous diseases. Topics include the functions of distinct tight junction proteins as barrier or channel formers for solutes and water, characteristics of the tight junction in inflammatory bowel diseases, posttranslational modifications of tight junction proteins, the relation between renal tight junction proteins and blood pressure control, and the molecular structure of claudin-claudin interactions NOTE: Annals volumes are available for sale as individual books or as a journal. For information on institutional journal subscriptions, please visit www.blackwellpublishing.com/nyas. ACADEMY MEMBERS: Please contact the New York Academy of Sciences directly to place your order (www.nyas.org). Members of the New York Academy of Science receive full-text access to the Annals online and discounts on print volumes. Please visit http://www.nyas.org/MemberCenter/Join.aspx for more information about becoming a member.

This book was written by many outstanding investigators who have spent decades to study different aspects of blood‐tissue barrier function. They have summarized some of the latest and fascinating development in their fields of research including the blood‐brain barrier, the blood‐retinal barrier, the gut barrier, the blood‐biliary barrier, the blood‐follicle barrier, the blood‐epididymis barrier, the blood‐testis barrier, the tight junction barrier in general as well as barriers in the female reproductive tract. Included are also chapters that focus on topics that are physiologically applicable to all blood‐tissue barriers. Many of these chapters also include information on specific human diseases, such as pathological changes of the gut barrier that cause bowel disorders resulting from inflammation of the epithelial lining in the intestine, and infertility in men as a result of disruption of the blood‐epididymal and/or blood‐testis barriers; and on new therapeutic approaches (e.g., drug delivery across the blood‐brain and the blood‐retinal barriers).