Enzymatic synthesis of astaxanthin n-octanoic acid esters.

We examined the enzymatic synthesis of astaxanthin n-octanoic acid esters. Carriers for the immobilized enzyme and reaction conditions such as water content, reaction temperature, and time were examined using Candida cylindracea lipase (Lipase OF). Lipase OF) immobilized by a hydrophobic anion exchange resin (10% w/w content of lipase) gave the best yield in the esterification reaction of astaxanthin. Two milligrams of astaxanthin per 750 microL tri-n-octanoin (ca. 0.3%) was optimum because of the low solubility of tri-n-octanoin. The esters were obtained in a yield of 36.4% under the optimal reaction conditions.

Involvement of mast cell chymase in bleomycin-induced pulmonary fibrosis in mice.

The possible role of mast cell chymase in organ fibrosis was examined using a bleomycin-induced pulmonary fibrosis model in mice. Intratracheal injection of bleomycin to mice significantly increased not only hydroxyproline content but also chymase activity in the lung. Administration of a chymase inhibitor SUN C8077 (7-chloro-3-(3-amynophenyl) quinazoline-2, 4-dione methanesulfonate) dose-dependently reversed the bleomycin-induced increase in hydroxyproline content as well as chymase activity in the lung. Human chymase digested latent transforming growth factor-beta1 (TGF-beta1) to form mature TGF-beta1 in vitro, which was inhibited by SUN C8077. Human chymase, on the other hand, failed to stimulate DNA synthesis of human lung fibroblasts CCD-8Lu and LL97A. Taken together, it is suggested that mast cell chymase might participate in the pathogenesis of pulmonary fibrosis, and that the chymase-induced fibrosis might be mediated at least in part by TGF-beta1. Chymase inhibitor may be promising for treatment of pulmonary fibrosis in humans.

Role of mast cell chymase in allergen-induced biphasic skin reaction.

Intradermal injection of human chymase (EC 3.4.21.39) into the mouse ear elicited an edematous skin reaction in a biphasic manner, with a transient reaction peaking at 1 hr, followed by a delayed response persisting for at least 24hr. The kinetics of this reaction was analogous to the biphasic skin reaction induced by ascaris extract in actively sensitized mice. A similarity between the two dermatitis models was also shown by histological analysis, i.e. accumulation of inflammatory cells was observed exclusively in the later phases of the skin reaction. A chymase inhibitor, SUN-C8077 [3-(3-aminophenylsulfonyl)-7-chloroquinazorine 2,4(1H, 3H)-dione], significantly inhibited both the early- and late-phase responses of the skin reaction induced by ascaris extract. These findings suggest that chymase may play an important role in the allergen-induced biphasic skin reaction. A histamine receptor antagonist, homochlorcyclizine, inhibited the early-phase but not the late-phase of the chymase-induced skin reaction. In addition, human chymase showed chemotactic activity to human polymorphonuclear leukocytes in vitro. Mast cell chymase may participate in the two phases of allergic skin inflammation by two distinct mechanisms, i.e. histamine- and leukocyte-dependent mechanisms, respectively.

Chymase participates in chronic dermatitis by inducing eosinophil infiltration.

An epicutaneous application of 2,4-dinitrofluorobenzene (DNFB) to a mouse ear caused a transient skin swelling, and the repetition of the challenge enlarged the contact dermatitis. The repeated challenge with DNFB also induced eosinophil infiltration on the application site. Administration of a chymase inhibitor significantly inhibited the ear swelling as well as eosinophil accumulation. An intradermal injection of human chymase to the mouse ear also elicited transient skin swelling and eosinophil infiltration, both of which were augmented in proportion to the number of injections. Human serum albumin and heat-inactivated chymase failed to induce such skin reactions, suggesting the participation of proteolytic activity of the enzyme. In addition, chymase stimulated eosinophil migration in vitro in a concentration-dependent manner. Taken together, these observations suggest that mast cell chymase may contribute to development of the DNFB-induced dermatitis, probably by promoting eosinophil infiltration. It is therefore possible that chymase plays a role in pathogenesis of chronic dermatitis such as atopic dermatitis.

Mast cell chymase regulates dermal mast cell number in mice.

Chymase inhibitor reduced the increase in the number of dermal mast cells in 2,4-dinitrofluorobenzene-induced dermatitis in a dose-dependent manner. Intradermal injection of human chymase to mouse ear significantly increased histamine content, the marker for mast cell number in the skin. These results suggest that chymase released by mast cells may participate in local mast cell accumulation in a positive feedback fashion. Immunohistochemical analysis revealed that the intradermal injection of chymase reduces expression of stem cell factor (SCF) on surface of the skin keratinocytes. In addition, incubation of human keratinocytes with chymase in vitro resulted in release of SCF into the culture medium. Since soluble SCF is thought to regulate mast cell number, the chymase-induced mast cell accumulation may occur via the ability of chymase to process membrane-bound SCF on the epidermal keratinocytes.