Identification of a prostaglandin D2 metabolite as a neuritogenesis enhancer targeting the TRPV1 ion channel.

Mast cells play important roles in allergic inflammation by secreting various mediators. In the present study, based on the finding that the medium conditioned by activated RBL-2H3 mast cells enhanced the nerve growth factor (NGF)-induced neuritogenesis of PC12 cells, we attempted to isolate an active compound from the mast cell conditioned culture medium. Our experiment identified 15-deoxy-Δ(12,14)-PGJ2 (15d-PGJ2), one of the PGD2 metabolites, as a potential enhancer of neuritogenesis. 15d-PGJ2 strongly enhanced the neuritogenesis elicited by a low-concentration of NGF that alone was insufficient to induce the neuronal differentiation. This 15d-PGJ2 effect was exerted in a Ca(2+)-dependent manner, but independently of the NGF receptor TrkA. Importantly, 15d-PGJ2 activated the transient receptor potential vanilloid-type 1 (TRPV1), a non-selective cation channel, leading to the Ca(2+) influx. In addition, we observed that (i) NGF promoted the insertion of TRPV1 into the cell surface membrane and (ii) 15d-PGJ2 covalently bound to TRPV1. These findings suggest that the NGF/15d-PGJ2-induced neuritogenesis may be regulated by two sets of mechanisms, one for the translocation of TRPV1 into the cell surface by NGF and one for the activation of TRPV1 by 15d-PGJ2. Thus, there is most likely a link between allergic inflammation and activation of the neuronal differentiation.

Phosphonium alkyl PEG sulfate ionic liquids as coating materials for activation of Burkholderia cepacia lipase.

Lipases are among the most widely used enzymes applicable for various substrates; however, the slow reactions or poor enantioselective reactions are sometimes obtained. To develop ionic liquid type activating agents for lipase, four types of phosphonium cetyl(PEG)10 sulfate ionic liquids have been synthesized and used as coating materials of Burkholderia cepacia lipase (Lipase PS) through the lyophilization process. Tributyl ([2-methoxy]ethoxymethyl)phosphonium cetyl(PEG)10 sulfate ([P444MEM ][C16 (PEG)10 SO4 ]) (PL1) worked best among them, and PL1-coated lipase PS displayed high reactivity in transesterification of broad types of secondary alcohols using vinyl acetate as an acylating reagent with perfect enantioselectivity (E > 200). The substrate preference of PL1-PS differs from that of commercial lipase PS or [bdmim] [C16 (PEG)10 SO4 ]-coated lipase (IL1-PS); PL1-PS displayed excellent enantioselectivity in the reaction of 2-chloro-1-phenylethanol with E > 200, though insufficient E values were recorded for lipase PS (E = 12) and IL1-PS (E = 123) for this alcohol. PL1-PS also showed perfect enantioselectivity (E > 200) for the reaction of 1-(pyridin-2-yl)ethanol, while IL1-PS showed E = 130 for this compound. We further succeeded in demonstrating the recyclable use of PL1-PS five times in tributyl(3-methoxypropyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P444PM ][Tf2 N]) as a solvent. Since PL1-PS is easily applicable to 10-20 gram-scaled reactions, it is expected that the IL-coated enzyme might be useful for practical preparation of a wide variety of chiral secondary alcohols.

15-deoxy-?(12,14)-prostaglandin J2 as a potential TRPV1-dependent atopic dermatitis enhancer.

Atopic dermatitis (AD) is a recurrent chronic inflammatory skin condition characterized by a complex pathogenesis, including skin barrier dysfunctions, allergy/immunology, and pruritus.In AD lesions, mast cells migrate into the epidermis, and exert their biological effects by releasing paracrine mediators. TRPV1, a non-selective cation channel widely expressed in skin tissues, has been shown to contribute to the development of diverse dermatoses and pruritus. In the present study, we identified a TRPV1 agonist as a neuritogenic enhancer produced from mast cells and characterized a possible molecular mechanism for the TRPV1-dependent neuritogenesis in AD. Based on the hypothesis that activated mast cells produce a TRPV1-dependent neuritogenic enhancer,we screened a number of inflammatory mediators for the neuritogenic-promoting activityand identified a PGD2 metabolite, 15-deoxy-?(12,14)-prostaglandin J2 (15d-PGJ2), as a potential neuritogenic enhancer derived from mast cells. 15d-PGJ2 significantly enhanced the nerve growth factor (NGF)-induced neuritogenesis in PC12 cells, and its enhancing potency was attributed to the electrophilic center of 15d-PGJ2. 15d-PGJ2 indeed activated TRPV1, leading to a significant increase in the intracellular Ca(2) level. In addition, the treatment of PC12 cells with biotinylated 15d-PGJ2 resulted in the formation of a 15d-PGJ2-TRPV1 adduct, indicating that 15d-PGJ2 directly modified the TRPV1 in the cells. Furthermore, 15d-PGJ2 facilitated the NGF-dependent signal transductions including ERK and JNK pathways in a Ca(2 ?)-dependent manner. These findings suggest that 15d-PGJ2 enhances NGF signaling via TRPV1-dependent Ca(2) influx, thereby acting as a potential neuritogenic enhancer in AD.

A food-derived synergist of NGF signaling: identification of protein tyrosine phosphatase 1B as a key regulator of NGF receptor-initiated signal transduction.

Neurotrophins, such as the nerve growth factor (NGF), play an essential role in the growth, development, survival and functional maintenance of neurons in the central and peripheral systems. They also prevent neuronal cell death under various stressful conditions, such as ischemia and neurodegenerative disorders. NGF induces cell differentiation and neurite outgrowth by binding with and activating the NGF receptor tyrosine kinase followed by activation of a variety of signaling cascades. We have investigated the NGF-dependent neuritogenesis enhancer potential of a food-derived small molecule contained in Brassica vegetables and identified the protein tyrosine phosphatase (PTP) 1B as a key regulator of the NGF receptor-initiated signal transduction. Based on an extensive screening of Brassica vegetable extracts for the neuritogenic-promoting activity in the rat pheochromocytoma cell line PC12, we found the Japanese horseradish, wasabi (Wasabia japonica, syn. Eutrema wasabi), as the richest source and identified 6-methylsulfinylhexyl isothiocyanate (6-HITC), an analogue of sulforaphane isolated from broccoli, as one of the major neuritogenic enhancers in the wasabi. 6-HITC strongly enhanced the neurite outgrowth and neurofilament expression elicited by a low-concentration of NGF that alone was insufficient to induce neuronal differentiation. 6-HITC also facilitated the sustained-phosphorylation of the extracellular signal-regulated kinase and the autophosphorylation of the NGF receptor TrkA. It was found that PTP1B act as a phosphatase capable of dephosphorylating Tyr-490 of TrkA and was inactivated by 6-HITC in a redox-dependent manner. The identification of PTP1B as a regulator of NGF signaling may provide new clues about the chemoprotective potential of food components, such as isothiocyanates.