Synthesis and Agonistic Activity at the GPR35 of 5,6-Dihydroxyindole-2-carboxylic Acid Analogues

5,6-Dihydroxyindole-2-carboxylic acid (DHICA), an intermediate of melanin synthesis and an eumelanin building block, was recently discovered to be a GPR35 agonist with moderate potency. Here, we report the synthesis and pharmacological characterization of a series of DHICA analogues against GPR35 using both label-free dynamic mass redistribution and Tango β-arrestin translocation assays. This led to identification of novel GPR35 agonists with improved potency and/or having biased agonism

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-10

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>GRL-amide (20 μM), SLIGKV-amide (20 μM), thrombin (40 unit/ml), SFLLR-amide (20 μM), trypsin (1024 nM), SFLLR-amide+SLIGRL-amide (each at 20 μM). (b) Comparison of the maximal DMR and Camobilization responses induced by different PAR agonists. The DMR response was calculated using the amplitude of the P-DMR event. Since trypsin at doses greater than ~1000 nM led to significant cell detachment (ref. 16), the DMR signal induced by trypsin at 1024 nM was used as its maximal response

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-1

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>IGRL-amide (20 μM), SLIGKV-amide (20 μM), thrombin (40 unit/ml), SFLLR-amide (20 μM), trypsin (1024 nM), SFLLR-amide+SLIGRL-amide (each at 20 μM). (b) Comparison of the maximal DMR and Camobilization responses induced by different PAR agonists. The DMR response was calculated using the amplitude of the P-DMR event. Since trypsin at doses greater than ~1000 nM led to significant cell detachment (ref. 16), the DMR signal induced by trypsin at 1024 nM was used as its maximal response

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-2

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>of the P-DMR events induced by each agonist (40 unit/ml thrombin, 20 μM SFLLR-amide, or 20 μM SLIGKV-amide) were plotted as a function of YFLLRNP-amide concentration

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-8

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>ypsin (100 nM), and thrombin (40 unit/ml). The cell responses with the pre-treatment with the HBSS only were also included as control

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-0

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>Gsignaling, which proceeds through activation of the receptor, its coupled G protein and downstream target phospholipase C (PLC). The PLC hydrolyzes the membrane lipid phosphatidylinositol bisphosphate (PIP), producing inositol triphosphate (IP) and diacylglycerol (DAG). IPbinds to and opens a calcium channel in the endoplasmic reticulum, leading to calcium mobilization. Calcium alters many cellular processes. The interaction of both DAG and calcium with protein kinase C (PKC) activates PKC kinase activity, which, in turn, phosphorylates many different protein targets including small GTPase Rho, leading to the remodeling of cytoskeletal structure. (b) The increase in intracellular Calevel as a function of the concentration of different soluble PAR agonists. (c) The real-time dynamic mass redistribution signals induced by SFLLR-amide at different doses. The solid arrow indicates the time when SFLLR-amide is introduced. The DMR consists of two phases: an increase signal (termed Positive-DMR, P-DMR) and a sequential decay signal (termed Negative-DMR, N-DMR). (d) The amplitudes of both P-DMR and N-DMR events, calculated as indicated in (c), as a function of SFLLR-amide concentration

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-9

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>Gsignaling, which proceeds through activation of the receptor, its coupled G protein and downstream target phospholipase C (PLC). The PLC hydrolyzes the membrane lipid phosphatidylinositol bisphosphate (PIP), producing inositol triphosphate (IP) and diacylglycerol (DAG). IPbinds to and opens a calcium channel in the endoplasmic reticulum, leading to calcium mobilization. Calcium alters many cellular processes. The interaction of both DAG and calcium with protein kinase C (PKC) activates PKC kinase activity, which, in turn, phosphorylates many different protein targets including small GTPase Rho, leading to the remodeling of cytoskeletal structure. (b) The increase in intracellular Calevel as a function of the concentration of different soluble PAR agonists. (c) The real-time dynamic mass redistribution signals induced by SFLLR-amide at different doses. The solid arrow indicates the time when SFLLR-amide is introduced. The DMR consists of two phases: an increase signal (termed Positive-DMR, P-DMR) and a sequential decay signal (termed Negative-DMR, N-DMR). (d) The amplitudes of both P-DMR and N-DMR events, calculated as indicated in (c), as a function of SFLLR-amide concentration

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-4

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>combinations of agonists. The agonist concentration was 40 unit/ml, 200 nM, 20 μM, 20 μM, and 100 nM for thrombin, trypsin, SFLLR-amide, SLIGKV-amide, and bradykinin, respectively

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-3

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p>combinations of agonists. The agonist concentration was 40 unit/ml, 200 nM, 20 μM, 20 μM, and 100 nM for thrombin, trypsin, SFLLR-amide, SLIGKV-amide, and bradykinin, respectively

Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells-5

<p><b>Copyright information:</b></p><p>Taken from "Optical biosensor differentiates signaling of endogenous PARand PARin A431 cells"</p><p>http://www.biomedcentral.com/1471-2121/8/24</p><p>BMC Cell Biology 2007;8():24-24.</p><p>Published online 22 Jun 2007</p><p>PMCID:PMC1925066.</p><p></p> Camobilization was examined. The agonists were trypsin (200 nM) and thrombin (40 unit/ml)