Increased levels of brain serotonin correlated with MMP-9 activity and IL-4 levels resulted in severe experimental autoimmune encephalomyelitis (EAE) in obese mice.

The aim of this study was to investigate the role of monoamine neurotransmitters on the severity of experimental autoimmune encephalomyelitis (EAE) in obese mice. EAE was induced in mice with normal diets (ND-EAE) and obese mice with high-fat diets (HFD-EAE) through the immune response to myelin oligodendrocyte glycoprotein (MOG) (35-55). The levels of dopamine (DA), serotonin (5-HT) and their metabolites in different anatomical brain regions were measured by high-performance liquid chromatography. The plasma and tissue NADPH oxidase and matrix metalloproteinases (MMP)-9 activities were analyzed by fluorescence spectrophotometry. The cumulative disease index and disease peaks were significantly higher in HFD-EAE compared with those in ND-EAE. Significantly higher 5-HT levels and lower 5-HT turnovers 5-hydroxyindole acetic acid ((5-HIAA)/5-HT) were found in the brains of HFD-EAE mice compared with those found in the HFD-CON and ND-EAE mice brains. Moreover, increased DA levels were observed in the caudate nucleus of the HFD-EAE mice compared with the control and ND-EAE mice. The NADPH oxidase and MMP-9 activities in the plasma and tissues were significantly higher in both the ND-EAE and HFD-EAE groups than in their respective controls. The cytokine levels in the plasma, tissues, and cultured splenocytes were found to be significantly altered in EAE mice compared with control mice. Moreover, HFD-EAE mice exhibited significantly higher MMP-9 activity and lower IL-4 levels than ND-EAE mice and were significantly correlated with brain 5-HT levels. In conclusion, the increased 5-HT levels in the brain significantly correlated with MMP-9 activity and IL-4 levels play an important role in the exacerbation of disease severity in HFD-EAE mice.

Acute exposure of human skin to ultraviolet or infrared radiation or heat stimuli increases mast cell numbers and tryptase expression in human skin in vivo.

BACKGROUND: Mast cells are key effector cells in diverse immunological and pathological processes. It is still unclear why there are more mast cells at peripheral and sun-exposed skin sites than at sun-protected sites. OBJECTIVES: To investigate changes in mast cell numbers associated with natural ageing and photoageing, and to observe the effects of ultraviolet (UV) and infrared (IR) radiation and heat on the prevalence of mast cells and tryptase expression in human skin in vivo. METHODS: Sun-exposed and sun-protected skin samples were taken from individuals in four different age groups. UV, IR or heat-treated buttock skin of young volunteers was also obtained. Mast cells were quantified by immunohistochemical staining of mast cell-specific tryptase and chymase. The expression of tryptase was determined by Western blotting. RESULTS: Both sun-exposed and sun-protected skin showed a gradual decrease in total mast cells (MC(Total)) number with ageing. The number of mast cells in sun-exposed skin was significantly higher than that in sun-protected skin. After UV irradiation (2 minimal erythema doses), MC(Total) and mast cells expressing tryptase and chymase were significantly increased at 24 and 48 h postirradiation. After IR irradiation (3 minimal heating doses) and heat treatment (43 degrees C for 90 min), MC(Total) reached peak induction at 8 and 48 h after stimulation, respectively. Tryptase expression was also clearly upregulated by UV, IR and heat. CONCLUSIONS: Our data demonstrate that mast cell numbers decreased with ageing in human skin. Also, mast cells may be activated and recruited by UV, IR and heat. These findings should further our understanding of the reason for the high prevalence of mast cells at peripheral sun-exposed skin sites.

Expression and secretion of the heterodimeric protein interleukin-12 in plant cell suspension culture.

It has been suggested that plant cell culture is the most suitable system for producing small-to-medium quantities of specialized, expensive, and high-purity proteins. Here, we report that a heterodimeric protein, human interleukin-12 (hIL-12), was expressed and secreted into culture medium in a biologically active form. A transgenic plant expressing hIL-12 was constructed by sexual crossing of plants that expressed each subunit of the protein. From a piece of transgenic plant, callus was induced and cell suspension culture was established. The biological activity and amount of hIL-12 secreted into culture medium were analyzed using bioassays and ELISA. Analysis of cellular localization demonstrated that the protein was secreted into the culture medium together with its intrinsic signal peptide.