[Search of (-)-Cytisine Derivatives as Potential Inhibitors of NF-κB and STAT1].

Design and synthesis ofnew derivatives of (-)-cytisine with a wide spectrum of pharmacological activity, represents the potential therapeutic interest for development of drug candidates for neurodegenerative disorders, inflammatory diseases, and treatment of nicotine addiction. We used HEK293 cell line transiently transfected with N F-κB and STATI luciferase reporter constructs to screen the (-)-cytisine derivatives for their potency to modulate basal and induced NF-κB and STAT1 activity. Currently, NF-κB, STAT1 and components of their signaling pathways are considered as attractive targets for pharmacological intervention, primarily in chronic inflammation, cancer, autoimmune, neurodegenerative and infectious diseases. The library of compounds included the derivatives of (-)-cytisine with amino-, amide-, thio- and carboxamide groups at 3, 5 and 12 position of the starting molecule, as well as some bimolecular derivatives. Our experimental data revealed compounds with moderate activating as well as inhibitory effects for basal NF-κB and STATI activity (IC50 or EC50 values are mainly in the micromolar range). The structure-activity relationship analysis demonstrated that the character of activity (activation or inhibition of NFκ-B and STAT1) is determined by the topology of the substituents at the (-)-cytisine molecule, whereas the nature of the substituents mainly contributes to severity of the effect (introduction of aromatic and adamantyl substituents, as well as thionyl or keto groups are of the principal importance). When evaluating the effect of (-)-cytisine derivatives on activity of NF-κB and STATI, induced by specific agents (TNFα and IFNγ, respectively) we observed that some compounds inhibited basal and stimulated activity of NF-κB and STAT1, another compounds showed the dual effect (an increase of basal- and a decrease of stimulated NF-κB activity) and several compounds increase both basal and induced activity of NF-κB and STAT1. Thus, obtained results suggest that one of the possible mechanisms of biological action of (-)-cytisine derivatives is their ability to influence the components of NF-κB and STAT1-dependent signaling pathways.

[Cellular test systems for the search for transcription factor activity modulators].

Test systems for monitoring activities and the search for substances activating or inhibiting transcription factors as biotargets have been designed on the basis of luciferase constructs containing binding sites for transcription factors CREB, NFAT, NF-kB, p53, STAT1, GAS, VDR, HSF1, and HIF1alpha. An assessment of the functional activity of reporter constructs has been carried out using their transient transfection into HEK293 cells followed by treatment with specific inducers. The functional activity of all reporter constructs was observed based on the increased luciferase expression. In order to evaluate the efficiency of the suggested test systems, aspirin was used. Incubation of cells transfected with the above-mentioned constructs treated with aspirin was accompanied by the suppression of NF-kB, HIF1alpha, GAS, VDR, and HSF binding activity. The findings revealed for NF-kB, NFAT, and STAT1 confirm the published data concerning the mechanisms of aspirin action. The detected effects of this drug on the HIF1alpha, GAS, VDR, and CREB activity have been demonstrated for the first time.

[To the mechanisms of antiarrhythmic action of Allapinine].

Allapinine (lappaconitine hydrobromide) is a drug for the treatment of cardiac arrhythmias, it shows IC class antiarrhythmics properties. Its action mechanism is associated with blockade of Na(+)-channels with subsequent inhibition of the depolarization rate and, consequently, of the slowing and reducing the excitability of the cardiac conduction system. At the moment, it is not established, what factors are associated with side effects of Allapinine, and therefore it seems important to study the molecular mechanisms of its action. The target genes were identified in a rat model of aconitine-induced arrhythmia using a commercial kit "Rat Neuroscience Ion Channels & Transporters RT2 Profiler PCR Array" (SABioscienses). Comparison of the expression of 84 genes in the experimental (aconitine arrhythmias/Allapinine) and control (aconitine arrhythmias/saline) animals revealed changes in the mRNA level of 18 genes. It has been shown an increase in mRNA levels of genes encoding various types of K(+)-channels (kcna6, kcnj1, kcnj4, kcnq2, kcnq4), Ca(2+)-channel (cacna 1g), vesicular acetylcholine transporter (slc 18a3). Decrease in the mRNA level was observed for genes encoding the Na(+)-channel (scn8a), K(+)-channels (kcne 1, kcns 1), membrane transporters (atp4a, slc6a9). Taken together, it appears that the effect of Allapinine on aconitine--induced arrhythmias is due to modulation of genes encoding Na(+)-, K(+)-, Ca(2+)-channels, conducting ionic currents (I(Na), I(to), I(Ks), I(K1), I(CaT)), which are involved in the formation of different phases of the action potential. The effect of the drug on the mRNA levels of genes encoding the acetylcholine and glycine transporters, suggesting the participation of these neurotransmitters in the mechanisms of anti-arrhythmic properties of the Allapinine.