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Ly6C hi monocytes migrate to injured sites and induce inflammation in the acute phase of tissue injury. However, once the causes of tissue injury are eliminated, monocyte-derived macrophages contribute to the resolution of inflammation and tissue repair. It remains unclear whether the emergence of these immunoregulatory macrophages is attributed to the phenotypic conversion of inflammatory monocytes in situ or to the recruitment of bone marrowderived regulatory cells de novo. Here, we identified a subpopulation of Ly6C hi monocytes that contribute to the resolution of inflammation and tissue repair. Ym1 + Ly6C hi monocytes greatly expanded in bone marrow during the recovery phase of systemic inflammation or tissue injury. Ym1 + Ly6C hi monocytes infiltrating into an injured site exhibited immunoregulatory and tissue-reparative phenotypes. Deletion of Ym1 + Ly6C hi monocytes resulted in delayed recovery from colitis. These results demonstrate that a distinct monocyte subpopulation destined to act in immunoregulation is generated in bone marrow and participates in resolution of inflammation and tissue repair. Emergence of immunoregulatory Ym1 + Ly6C hi monocytes during recovery phase of tissue injury.

BackgroundFor the detection of allergen-specific IgE in sera, solid-phase IgE-binding assays like the CAP test are commonly used. Although such immunochemical methods are very sensitive, they frequently produce false positives. Degranulation of the human IgE receptor (FcεRI)-transfected rat mast cell (RBL) lines seems to be a possible indicator for human IgE, but spontaneous mediator release from these cells in the presence of human sera is not negligible.MethodsThe nuclear factor of activated T-cells (NFAT)-responsive luciferase reporter gene was stably transfected into human FcεRI-expressing RBL-SX38 cells. One established clone (RS-ATL8) was sensitized with 1 : 100 dilution of sera from patients with egg white allergy and then stimulated with purified or a crude extract of egg white allergen.ResultsSensitization with 15 pg/ml IgE was sufficient to detect IgE crosslinking–induced luciferase expression (EXiLE) by anti-IgE stimulation. Allergen-specific EXiLE was elicited by as little as 1 fg/ml of egg white protein without cytotoxicity. There was a good correlation between results with EXiLE and oral food challenge tests on patients with egg allergy (P = 0.001687, Fisher's exact test). The measured values of EXiLE and the CAP test also correlated well (R = 0.9127, Spearman's test).ConclusionThe EXiLE test using RS-ATL8 cells is a promising in vitro IgE test to evaluate the biological activity of the binding between IgE and allergens.

UV radiation causes a number of harmful events including growth delay, cell death and ultimately cancer. The reversal of such effects by concomitant exposure to visible light is a conserved mechanism which has been uncovered in many multi-cellular organisms. Here we show that light-dependent UV-tolerance is a cell autonomous phenomenon in zebrafish. In addition, we provide several lines of evidence indicating that light induction of 64PHR, a DNA repair enzyme, and the subsequent light-dependent DNA repair mediated by this enzyme are prerequisites for light-mediated UV tolerance. 64PHR is evolutionary related to and has a high degree of structural similarity to animal CRY, an essential circadian regulator. The zebrafish circadian clock is controlled by a cell-autonomous and light-dependent oscillator, where zCRY1a functions as an important mediator of light entrainment of the circadian clock. In this study, we show that light directly activates MAPK signaling cascades in zebrafish cells and we provide evidence that light-induced activation of these pathways controls the expression of two evolutionary-related genes, z64Phr and zCry1a, revealing that light-dependent DNA repair and the entrainment of circadian clock share common regulatory pathways.

INTRODUCTIONFrom bacteria to humans, almost all organisms can adapt the timing of their physiology to the cyclic changes of their environment, thanks to a naturally-selected intrinsic timekeeping system called the circadian clock. 1) The circadian clock enhances the physiological efficiency and survival of an organism by organizing its behavior and body functions. 2,3) During the circadian day, the organism's physiology is given over to catabolic processes, whereas the anabolic functions of growth, repair and consolidation occur at night. To achieve this schedule in mammals, the circadian clock regulates a number of physiological functions, including sleep and wakefulness, food intake, body temperature, cardiovascular and renal activity, hormone production, hepatic metabolism and immune responses. 4,5) Accordingly, disruption of the circadian clock in humans has been linked to profound effects on health, including insomnia, stomach ailments, depression and cancer. 4,5) In most organisms, the molecular mechanisms underlying the establishment and maintenance of biological rhythms comprise interconnected transcription-translation feedback loops in which some clock factors repress their own transcription once they have attained critical levels. 2,3) These oscillators have the property of being endogenous and cellautonomous systems that maintain their rhythm in the absence of external time cues. 6) Both vertebrates and invertebrates have circadian oscillators scattered throughout their bodies. 7,8) In mammals, the circadian system is composed of both central and peripheral oscillators. 7) The mammalian central clock is located in the suprachiasmatic nucleus (SCN) within the anterior hypothalamus of the brain. 9) This central clock acts as a coordinator and provides time signals via both neural and humoral routes that entrain independent peripheral clocks. Dysfunction of the central clock does not inactivate the peripheral clocks but instead causes individual peripheral oscillators to become temporally uncoupled. [10][11][12] To guarantee that an organism's behavior remains tied to the rhythms of its environment, the circadian clock must be able to reset itself in response to environmental cues. 9,13,14) The main environmental stimulus for organisms is light, which is provided in day-night cycles. Mammals have no photoreceptors in peripheral tissues, 15) so that the effect of light on peripheral clocks is indirect. 13) For the mammalian clock, the SCN integrates photic cues from the retina and uses neural and humoral signals to transmit this information to peripheral clocks, synchronizing them. [16][17][18] This communication between the central and peripheral clocks results in the seamless regulation of fundamental physiological functions. 4,8) Interestingly, peripheral clocks can also respond directly to SCN-independent signals such as feeding and temperature change. 19,20) However, the physiological role of SCN-independent responses of peripheral clocks is not yet fully understood. A recent study has reported that ...