• Biomolecules & Therapeutics
• /
• 제25권5호
• /
• pp.497-503
• /
• 2017

Recent reports claimed that glucosylsphingosine (GS) is highly accumulated and specifically evoking itch-scratch responses in the skins of atopic dermatitis (AD) patients. However, it was unclear how GS can trigger itch-scratch responses, since there were no known molecular singling pathways revealed yet. In the present study, it was verified for the first time that GS can activate mouse serotonin receptor 2a (mHtr2a) and 2b (mHtr2b), but not 2c (mHtr2c) that are expressed in HEK293T cells. Specifically, effects of GS on all mouse serotonin receptor 2 subfamily were evaluated by calcium imaging techniques. The GS-induced intracellular calcium increase was dose-dependent, and antagonists such as ketanserin (Htr2a antagonist) and RS-127445 (Htr2b antagonist) significantly blocked the GS-induced responses. Moreover, the proposed GS-induced responses appear to be mediated by phospholipase C (PLC), since pretreatment of a PLC inhibitor U-73122 abolished the GS-induced responses. Additionally, the GS-induced calcium influx is probably mediated by endogenous TRPC ion channels in HEK293T cells, since pretreatment of SKF-96365, an inhibitor for TRPC, significantly suppressed GS-induced response. In conclusion, the present study revealed for the first time that GS can stimulate mHtr2a and mHtr2b to induce calcium influx, by utilizing PLC-dependent pathway afterwards. Considering that GS is regarded as a pruritogen in AD, the present study implicates a novel GS-induced itch signaling pathway.

• Bulletin of the Korean Chemical Society
• /
• 제32권6호
• /
• pp.2008-2014
• /
• 2011

Serotonin or 5-hydroxytryptamine subtype 2C ($5-HT_{2C}$) receptor belongs to class A amine subfamily of G-protein-coupled receptor (GPCR) super family and its ligands has therapeutic promise as anti-depressant and -obesity agents. So far, bovine rhodopsin from class A opsin subfamily was the mostly used X-ray crystal template to model this receptor. Here, we explained homology model using beta 2 adrenergic receptor (${\beta}$2AR), the model was energetically minimized and validated by flexible ligand docking with known agonists and antagonists. In the active site Asp134, Ser138 of transmembrane 3 (TM3), Arg195 of extracellular loop 2 (ECL2) and Tyr358 of TM7 were found as important residues to interact with agonists. In addition to these, V208 of ECL2 and N351 of TM7 was found to interact with antagonists. Several conserved residues including Trp324, Phe327 and Phe328 were also found to contribute hydrophobic interaction. The predicted ligand binding mode is in good agreement with published mutagenesis and homology model data. This new template derived homology model can be useful for further virtual screening based lead identification.

• The Korean Journal of Physiology and Pharmacology
• /
• 제7권5호
• /
• pp.279-282
• /
• 2003

To investigate the effect of fluoxetine, one of selective serotonin reuptake inhibitors (SSRIs), on the immune system, human peripheral blood mononuclear cells (PBMC) were treated with fluoxetine $(10^{-7}\;M)$ for 24 h, and immune-related genes were analyzed by cDNA microarray. Expression of the immunerelated genes such as CD107b (LAMP-2), CD47 receptor (thrombospondin receptor), CD5 antigen-like (scavenger receptor cysteine rich family), copine III (CPNE3), interleukin (IL)-18 (interferon-gammainducing factor), integrin alpha 4 (CD49d), integrin alpha L subunit (CD11a), IL-3 receptor alpha subunit, L apoferritin, and small inducible cytokine subfamily A (Cys-Cys) member 13 (SCYA13) was induced by fluoxetine. This result suggests that fluoxetine may affect the immune system, and provides fundamental data for the involvement of SSRIs on immunoregulation.