Allergic airway inflammation is associated with activation of innate immune pathways by allergens. Acute exacerbations of asthma are commonly associated with rhinovirus infection. Here we show that, after exposure to house dust mite (HDM) or rhinovirus infection, the E3 ubiquitin ligase midline 1 (MID1) is upregulated in mouse bronchial epithelium. HDM regulates MID1 expression in a Toll-like receptor 4 (TLR4)- and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-dependent manner. MID1 decreases protein phosphatase 2A (PP2A) activity through association with its catalytic subunit PP2Ac. siRNA-mediated knockdown of MID1 or pharmacological activation of PP2A using a nonphosphorylatable FTY720 analog in mice exposed to HDM reduces airway hyperreactivity and inflammation, including the expression of interleukin-25 (IL-25), IL-33 and CCL20, IL-5 and IL-13 release, nuclear factor (NF)κB activity, p38 mitogen-activated protein kinase (MAPK) phosphorylation, accumulation of eosinophils, T lymphocytes and myeloid dendritic cells, and the number of mucus-producing cells. MID1 inhibition also limited rhinovirus-induced exacerbation of allergic airway disease. We found that MID1 was upregulated in primary human bronchial epithelial cells upon HDM or rhinovirus exposure, and this correlated with TRAIL and CCL20 expression. Together, these findings identify a key role of MID1 in allergic airway inflammation and links innate immune pathway activation to the development and exacerbation of asthma.

Protein kinases represent promising anticancer drug targets. We describe here the meriolins, a new family of inhibitors of cyclin-dependent kinases (CDK). Meriolins represent a chemical structural hybrid between meridianins and variolins, two families of kinase inhibitors extracted from various marine invertebrates. Variolin B is currently in preclinical evaluation as an antitumor agent. A selectivity study done on 32 kinases showed that, compared with variolin B, meriolins display enhanced specificity toward CDKs, with marked potency on CDK2 and CDK9. The structures of pCDK2/cyclin A/variolin B and pCDK2/cyclin A/meriolin 3 complexes reveal that the two inhibitors bind within the ATP binding site of the kinase, but in different orientations. Meriolins display better antiproliferative and proapoptotic properties in human tumor cell cultures than their parent molecules, meridianins and variolins. Phosphorylation at CDK1, CDK4, and CDK9 sites on, respectively, protein phosphatase 1A, retinoblastoma protein, and RNA polymerase II is inhibited in neuroblastoma SH-SY5Y cells exposed to meriolins. Apoptosis triggered by meriolins is accompanied by rapid Mcl-1 down-regulation, cytochrome c release, and activation of caspases. Meriolin 3 potently inhibits tumor growth in two mouse xenograft cancer models, namely, Ewing's sarcoma and LS174T colorectal carcinoma. Meriolins thus constitute a new CDK inhibitory scaffold, with promising antitumor activity, derived from molecules initially isolated from marine organisms. [Cancer Res 2007;67(17):8325-34]

We report the synthesis and biological characterization of 3-(pyrimidin-4-yl)-7-azaindoles (meriolins), a chemical hybrid between the natural products meridianins and variolins, derived from marine organisms. Meriolins display potent inhibitory activities toward cyclin-dependent kinases (CDKs) and, to a lesser extent, other kinases (GSK-3, DYRK1A). The crystal structures of 1e (meriolin 5) and variolin B (Bettayeb, K.; Tirado, O. M.; Marionneau-Lambert, S.; Ferandin, Y.; Lozach, O.; Morris, J.; Mateo-Lozano, S.; Drückes, P.; Schächtele, C.; Kubbutat, M.; Liger, F.; Marquet, B.; Joseph, B.; Echalier, A.; Endicott, J.; Notario, V.; Meijer, L. Cancer Res. 2007, 67, 8325-8334) in complex with CDK2/cyclin A reveal that the two inhibitors are orientated in very different ways inside the ATP-binding pocket of the kinase. A structure-activity relationship provides further insight into the molecular mechanism of action of this family of kinase inhibitors. Meriolins are also potent antiproliferative and proapoptotic agents in cells cultured either as monolayers or in spheroids. Proapoptotic efficacy of meriolins correlates best with their CDK2 and CDK9 inhibitory activity. Meriolins thus constitute a promising class of pharmacological agents to be further evaluated against the numerous human diseases that imply abnormal regulation of CDKs including cancers, neurodegenerative disorders, and polycystic kidney disease.

under the supervision of Assoc. Prof. Emily Parker. He is currently a postdoctoral fellow in the Morris group at the University of Adelaide. His research interests focus on the synthesis of biologically active compounds. Erin Carter obtained her B.Sc. (Hons) degree from Flinders University, Australia, in 2004. She is currently working toward her Ph.D. degree with Dr. Jonathan Morris at the University of Adelaide, where she is carrying out research on the variolins.

Specific forms of the lipid ceramide, synthesized by the ceramide synthase enzyme family, are believed to regulate metabolic physiology. Genetic mouse models have established C16 ceramide as a driver of insulin resistance in liver and adipose tissue. C18 ceramide, synthesized by ceramide synthase 1 (CerS1), is abundant in skeletal muscle and suggested to promote insulin resistance in humans. We herein describe the first isoform-specific ceramide synthase inhibitor, P053, which inhibits CerS1 with nanomolar potency. Lipidomic profiling shows that P053 is highly selective for CerS1. Daily P053 administration to mice fed a high-fat diet (HFD) increases fatty acid oxidation in skeletal muscle and impedes increases in muscle triglycerides and adiposity, but does not protect against HFD-induced insulin resistance. Our inhibitor therefore allowed us to define a role for CerS1 as an endogenous inhibitor of mitochondrial fatty acid oxidation in muscle and regulator of whole-body adiposity.

Fissure coupling of the fluoranthene adduct (7,12-diphenyl)benzo[k]fluoranthene (3) using AlCl3/NaCl, CoF3/TFA, or Tl(OCOCF3) gave the new polyaromatic hydrocarbon dibenzo{[f,f’]-4,4’,7,7’-tetraphenyl}diindeno[1,2,3-cd:1‘,2‘,3‘-lm]perylene (4). Crystal data for 4:  triclinic space group P1̄, a = 10.569(2) Å, b = 11.565(4) Å, c = 13.001(3) Å, α = 95.05(2)°, β = 111.24(1)°, γ = 100.53(1)°, Z = 1, R F = 0.075%. Compounds 3 and 4 are both highly fluorescent in solution and display relative fluorescence quantum yields of φF = 1.0 and 0.85, respectively. The electrochemistry and electrogenerated chemiluminescence (ECL) of each compound has been investigated. The cyclic voltammogram of 3 in benzene−acetonitrile (9:1) shows that the compound undergoes a reversible reduction and an irreversible oxidation, whereas the cyclic voltammogram of 4 displays the reversible formation of both singly and doubly charged cations and anions. Compounds 3 and 4 undergo ECL to yield blue and orange-red light, respectively, with an ECL efficiency of ∼2% for 4. Emission from 4 is observed in the ECL of unstirred solutions of 3. This indicates that 4 is produced at the electrode during the ECL experiment, presumably via an electrochemical oxidative coupling process during the anodic potential steps.

Upon oxidation at a platinum electrode, (7,12-diphenyl)benzo[k]fluoranthene (1) undergoes intermolecular dehydrogenative coupling to form bis-4,4'-(7,12-diphenyl)benzo[k]fluoranthene (2). Further oxidation of this product results in a much slower intramolecular coupling reaction that yields dibenzo{[f,f']-4,4',7,7'-tetraphenyl}diindeno[1,2,3-cd:1',2',3'-lm]perylene (3). 2 can be synthesized via bulk electrolysis of 1 and also by the chemical coupling of 4-bromo-7,12-diphenylbenzo[k]fluoranthene (4) with a nickel catalyst. Compounds 1-3 are capable of electrogenerated chemiluminescence (ECL), and their coupling reactions have been detected and followed using this technique. Cyclic voltammograms of 1 have been digitally simulated to provide mechanistic and kinetic insight into the initial intermolecular oxidative coupling reaction. Evidence supports an EC(2)()EE mechanism, in which the coupling of radical cations of 1 is the rate-limiting step. A second-order rate constant of k = 7500 M(-)(1) s(-)(1) has been determined for the dimerization process by fitting experimental data to theoretical working curves.

Serine/arginine-protein kinase 1 (SRPK1) regulates alternative splicing of VEGF-A to pro-angiogenic isoforms and SRPK1 inhibition can restore the balance of pro/antiangiogenic isoforms to normal physiological levels. The lack of potency and selectivity of available compounds has limited development of SRPK1 inhibitors, with the control of alternative splicing by splicing factor-specific kinases yet to be translated. We present here compounds that occupy a binding pocket created by the unique helical insert of SRPK1, and trigger a backbone flip in the hinge region, that results in potent (<10 nM) and selective inhibition of SRPK1 kinase activity. Treatment with these inhibitors inhibited SRPK1 activity and phosphorylation of serine/arginine splicing factor 1 (SRSF1), resulting in alternative splicing of VEGF-A from pro-angiogenic to antiangiogenic isoforms. This property resulted in potent inhibition of blood vessel growth in models of choroidal angiogenesis in vivo. This work identifies tool compounds for splice isoform selective targeting of pro-angiogenic VEGF, which may lead to new therapeutic strategies for a diversity of diseases where dysfunctional splicing drives disease development.