Caffeoyl-Prolyl-Histidine Amide Inhibits Fyn and Alleviates Atopic Dermatitis-Like Phenotypes via Suppression of NF-κB Activation.

Caffeic acid (CA) is produced from a variety of plants and has diverse biological functions, including anti-inflammation activity. It has been recently demonstrated that caffeoyl-prolyl-histidine amide (CA-PH), which is CA conjugated with proline-histidine dipeptide, relieves atopic dermatitis (AD)-like phenotypes in mouse. In this study, we investigated the molecular mechanism underlying CA-PH-mediated alleviation of AD-like phenotypes using cell line and AD mouse models. We confirmed that CA-PH suppresses AD-like phenotypes, such as increased epidermal thickening, infiltration of mast cells, and dysregulated gene expression of cytokines. CA-PH suppressed up-regulation of cytokine expression through inhibition of nuclear translocation of NF-κB. Using a CA-PH affinity pull-down assay, we found that CA-PH binds to Fyn. In silico molecular docking and enzyme kinetic studies revealed that CA-PH binds to the ATP binding site and inhibits Fyn competitively with ATP. CA-PH further suppressed spleen tyrosine kinase (SYK)/inhibitor of nuclear factor kappa B kinase (IKK)/inhibitor of nuclear factor kappa B (IκB) signaling, which is required for nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. In addition, chronic application of CA-PH, in contrast with that of glucocorticoids, did not induce up-regulation of regulated in development and DNA damage response 1 (REDD1), reduction of mammalian target of rapamycin (mTOR) signaling, or skin atrophy. Thus, our study suggests that CA-PH treatment may help to reduce skin inflammation via down-regulation of NF-κB activation, and Fyn may be a new therapeutic target of inflammatory skin diseases, such as AD.

The tri-peptide GHK-Cu complex ameliorates lipopolysaccharide-induced acute lung injury in mice.

The tripeptide-copper complex glycyl-l-histidyl-l-lysine-Cu (II) (GHK-Cu) is involved in wound healing and tissue remodeling. Although GHK-Cu exhibits anti-aging and tissue renewing properties, its roles in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are still unknown. Therefore, we examined the effects of GHK-Cu in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages in vitro and ALI in mice in vivo. GHK-Cu treatment reduced reactive oxygen species (ROS) production, increased superoxide dismutase (SOD) activity while decreased TNF-α and IL-6 production through the suppression of NF-κB p65 and p38 MAPK signaling in vitro and in vivo model of ALI. Moreover, GHK-Cu attenuated LPS-induced lung histological alterations, suppressed the infiltration of inflammatory cells into the lung parenchyma in LPS-induced ALI in mice. Taken together, these findings demonstrate that GHK-Cu possesses a protective effect in LPS-induced ALI by inhibiting excessive inflammatory responses; accordingly it may represent a novel therapeutic approach for ALI/ARDS.

Inhibition of lipopolysaccharide-induced inducible nitric oxide synthase expression by a novel compound, mercaptopyrazine, through suppression of nuclear factor-kappaB binding to DNA.

Macrophage cells in response to cytokines and endotoxins produced a large amount of nitric oxide (NO) by expression of inducible nitric oxide synthase (iNOS), resulting in acute or chronic inflammatory disorders including septic hypotension and atherosclerosis. In the present study, we investigated the effect and the mechanism of mercaptopyrazine (MP) in the induction of iNOS and NO production as a culminating factor for several inflammatory disorders. Pretreatment of MP alleviated the mortality of endotoxemic mice receiving a lethal bolus of lipopolysaccharide (LPS), which was associated with the reduced levels of serum nitrite/nitrate and IL-1beta. In RAW264.7 mouse macrophage cells, MP (300microM) inhibited both protein and mRNA levels of iNOS stimulated by LPS/interferon-gamma (IFNgamma) up to 50%. The nuclear factor-kappa B (NF-kappaB)-driven transactivation was also suppressed by MP to the same degree. Treatment of MP reduced the binding of NF-kappaB to the oligonucleotides containing NF-kappaB consensus sequence, while it did not affect the translocation of NF-kappaB to nuclear. Suppression of NF-kappaB activity by MP was completely reversed by a reducing agent, dithiothreitol, implying that MP might oxidize the sulfhydryl group(s) of DNA binding domain of NF-kappaB. In conclusion, MP would be one of interesting candidates or chemical moieties of iNOS expression inhibitor via specific suppression of NF-kappaB binding to DNA, and be useful as a chemopreventive agent or a therapeutic against iNOS-associated inflammatory diseases.

Titanium-Mediated Cyclization of omega-Vinyl Imides in Alkaloid Synthesis: Isoretronecanol, Trachelanthamidine, 5-Epitashiromine, and Tashiromine.

A new method for the stereocontrolled synthesis of pyrrolizidine and indolizidine alkaloids by means of titanium-mediated cyclization of omega-vinyl imides is described. The general procedure involves treatment of readily available omega-vinyl imides 9 and 10 with 2.5 equiv of cyclopentylmagnesium chloride in the presence of ClTi(O-i-Pr)(3) (1.1 equiv) and subsequent stereoselective reduction of the N-acylaminal group. The cis and trans ring junction stereoisomers can be stereoselectively prepared by catalytic hydrogenation (H(2), PtO(2), EtOAc) and NaCNBH(3) reduction (TFA, MeOH), respectively. Finally, treatment of the resulting lactams with LAH or diborane afforded the target alkaloids 1-8 in good yields.