![]() Taurine tissue distribution is characterized by low concentrations of taurine in the plasma and extracellular fluids (ranging from 10 to 100 μM) and high intracellular concentrations of taurine reaching up to 50 mM, depending on the cell type (Huxtable 1992 Learn et al. We will focus on the role of TauCl in the regulation of inflammation in rheumatoid arthritis, the best studied diseases in our laboratories (Marcinkiewicz and Kontny 2012). We asked the question whether taurine and/or taurine haloamines play a role in the pathogenesis of inflammatory diseases. The above information clearly suggests that antioxidants play a crucial role in maintaining homeostasis and in amelioration of the harmful effect of oxidative stress. Such a scenario may contribute to pathogenesis of inflammatory diseases, in which the neutrophil MPO–halide system is involved (Fig. On the other hand, overproduction of these oxidants and insufficient neutralization by antioxidants may lead to the development of oxidative stress and chronic inflammation (Smith 1994 Weiss 1988). The microbicidal effects of HOCl have been linked to oxidation of methionine residues in bacterial cytosolic and inner membrane proteins (Rosen et al. $$īoth hypohalous acids, HOCl and HOBr, are components of innate immunity and protect the host from infections by using their oxidizing potential to kill pathogens, but they may also damage host tissue. In neutrophil phagolysosomes, myeloperoxidase (MPO) uses H 2O 2 to convert chloride ion to HOCl, or bromide ion to HOBr (Klebanoff 1968 Thomas 1979 Henderson et al. Oxidant production begins when a membrane-associated NADPH oxidase reduces molecular oxygen to superoxide, which then yields H 2O 2. Upon contact with a pathogen, activated phagocytes (both neutrophils and macrophages) produce a respiratory burst characterized by intense uptake of oxygen. Moreover, MPO can also oxidize Br − to produce hypobromous acid (HOBr) (Thomas et al. Remarkably, MPO is the only mammalian enzyme that oxidizes Cl − into HOCl (Gaut et al. The myeloperoxidase–halide system plays a unique role in killing pathogens phagocytosed by neutrophils (Klebanoff 1968, 2005) through generation of hypochlorous acid (HOCl), a potent microbicidal and cytotoxic oxidant (Thomas 1979). The major cells involved in acute inflammation are neutrophils: phagocytes responsible for microbial killing and for generation of various proinflammatory mediators. This response, mediated predominantly by innate immunity, is responsible for elimination of these injurious stimuli and for the subsequent healing process. We will discuss the possible contribution of taurine and taurine haloamines to the pathogenesis of inflammatory diseases, especially in the best studied example of rheumatoid arthritis.Īcute inflammation is a physiological response of tissues to harmful stimuli such as pathogens, damaged cells or cancer cells and irritants. The aim of this paper is to show links between inflammation, neutrophils, MPO, oxidative stress and taurine. This review summarizes our current knowledge concerning the role of taurine, TauCl and TauBr in the pathogenesis of inflammatory diseases initiated or propagated by MPO-derived oxidants. In contrast to a well-documented regulatory role of taurine and taurine haloamines (TauCl, TauBr) in acute inflammation, their role in the pathogenesis of inflammatory diseases is not clear. Both haloamines, TauCl and taurine bromamine (TauBr), the product of taurine reaction with hypobromous acid (HOBr), exert antimicrobial and anti-inflammatory properties. This reaction results in the formation of less toxic taurine chloramine (TauCl). Indeed, at the site of inflammation, taurine is known to react with and detoxify hypochlorous acid generated by the neutrophil myeloperoxidase (MPO)–halide system. It suggests that taurine may play an important role in inflammation associated with oxidative stress. Although these properties are not tissue specific, taurine reaches particularly high concentrations in tissues exposed to elevated levels of oxidants (e.g., inflammatory cells). Moreover, attenuation of apoptosis and its antioxidant activity seem to be crucial for the cytoprotective effects of taurine. Taurine (2-aminoethanesulfonic acid) is the most abundant free amino acid in humans and plays an important role in several essential biological processes such as bile acid conjugation, maintenance of calcium homeostasis, osmoregulation and membrane stabilization.
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