AbstractsBiology & Animal Science

The main goal of this dissertation is to identify novel modulators acting on ATP Binding Cassette subfamily C member 2 (ABCC2) transporters and α2-adrenoceptors subtypes. With the purpose of identifying novel modulators and their mode of action, a combination of experimental and computational approaches have been used. The first protein presented in this dissertation is the ABCC2 transporter, also known as the multidrug resistance associated protein 2 (MRP2), an efflux transporter expressed in polarized cells where it effluxes a variety of both endogenous and exogenous molecules out of the cell. The most common way to study the interactions between small molecules and ABCC2 transporter is by a vesicle transport assay. Three assays are commercially available, which use different probes to define the ABCC2- transport. With the intent to define the different assays and identify the effect that small molecules have on the ABCC2-transport, a small set of eight compounds and, subsequently a larger library of compounds were tested with the different assays. Additionally, the aim was to identify and characterise novel ABCC2 inhibitors, 16 inhibitors have been identified from the larger library and classification models were built to identify important descriptors that were able to discriminate inhibitors from inactive molecules. Instant structure-activity relationships (SAR) of four scaffolds of ABCC2 modulators are also presented. In addition, some unpublished results are presented, the homology model of ABCC2 and further insights into the SAR of ABCC2 modulators. The other proteins included in this dissertation are the three subtypes of the α2-adrenoceptors, G-protein coupled receptors, involved in the signalling pathway of adrenaline and noradrenaline. A clear subtype characterization/profile of these proteins is not available. Selective molecules could be used in treatment of high blood pressure, in the alleviation of withdrawal symptoms, and as anaesthetic with fewer side effects than the current drugs. To define the affinity of a small set of antagonists and outline the involvement of the first transmembrane helix in ligand binding, a competition binding assay has been used with chimera receptors where the first transmembrane helix has been swapped between the three subtypes. Molecular modelling has been used to explain the different binding affinities to the chimera receptors. Additionally, the aim was to identify novel α2B-adrenoceptor selective compounds, thus a mid-sized library has been screened using a miniaturized binding assay. Hierarchical classification and chemoinformatics analysis has been used to visualize and analyse the screening results. Väitöskirja käsittelee uusien ABCC2-kuljetinproteiinin modulaattoreiden ja α2 adrenoseptorialatyyppien inhibiittoreiden tunnistusta sekä kokeellisia että laskennallisia menetelmiä käyttäen. Väitöskirjan aluksi käsittelen ABBCC2-kuljetinproteiinia (ATP Binding Casette -proteiiniperhe, ryhmä C, alatyyppi 2), joka tunnetaan myös MRP2-proteiinina…