Membrane translocation of vinculin after UVA exposure facilitates melanosome trafficking.

Skin pigmentation is among the defenses against ultraviolet (UV) radiation. During formation of skin pigmentation, melanosomes that are transported to the cell membrane and released are internalized by keratinocytes. We here examined whether vinculin, the origin of actin fibers, is involved in this intracellular transport of melanosomes by using melanocytes with suppressed vinculin expression. Using fluorescence immunostaining, the migration of vinculin to the cell membrane due to exposure to 365-nm LED light was examined. The intracellular distribution of melanosomes after irradiation was weighted toward the pericellular region compared with non-irradiated cells. With the suppression of vinculin expression, the amount of extracellularly released melanin decreased. We conclude that the membrane migration of vinculin after UVA exposure is involved in the intracellular transport of melanosomes.

Interferon gamma, lipopolysaccharide, and modified-live viral vaccines stimulation alter the mRNA expression of tumor necrosis factor α, inducible nitric oxide synthase, and interferon ß in bovine alveolar macrophages.

To understand the pathogenesis of bovine respiratory disease (BRD), it is necessary to elucidate the mechanisms of alveolar macrophage regulation by cytokines and pathogen-associated molecular patterns (PAMPs). Moreover, "non-specific effects (NSEs)" an innate immune regulatory mechanism in response to vaccines containing PAMPs, has recently attracted attention. It may be applied to BRD control, but there is limited knowledge in bovine. To investigate this, we stimulated alveolar macrophages in vitro with lipopolysaccharide (LPS), polyinosinic-polycytidylic acid sodium salt (Poly I:C), interferon gamma (IFN-γ), and modified-live viral (MLV) vaccines, respectively, and analyzed changes in tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and interferon beta (IFN-ß) mRNA expression levels. mRNA expression levels of TNF-α, iNOS, and IFN-ß were significantly increased in bovine alveolar macrophages stimulated by IFN-γ and MLV vaccine; LPS, IFN-γ, and MLV vaccine; and MLV vaccine only, respectively. Additionally, all MLV vaccine-stimulated mRNA expression increases were observed in a concentration-dependent manner. These results revealed in part, the mechanism of bovine alveolar macrophage regulation by cytokines and PAMPs. Understanding the regulatory mechanisms of alveolar macrophages will contribute to understanding the pathogenesis of BRD and preventive and therapeutic BRD management based on NSEs.