Dr sci Nikolić Aleksandra, Dr sci nBobić Branko, Dr sci Štajner Tijana , Dr sci Jelena Srbljanović, Dr sci Vitomir Đokić Dr sci Vladimir Ivović, Dr sci Marija Vujanić, Dr sci Ksenija Slavić, Dr sci Irena Rajnprecht, Dr Neda Bauman

The goal of this multidisciplinary project, which integrates basic, applied and developmental research on infections caused by leading apicomplex pathogens, is to improve the control of toxoplasmosis and malaria, by improving therapeutic options and developing strategies for the prevention of infection, which will contribute to the improvement of control both at the clinical level and at the level public health. The scientific importance of the planned results lies in the contribution to the knowledge of the pathogenesis of malaria and toxoplasmosis. Basic research on the metabolic processes and transport molecules involved in these contribute to the understanding of the complex relationship established between the parasite and the host, and indicate potential sites of action of future drugs. The development of new transgenic lines as well as their characterization will increase the arsenal of tools available for the identification of further therapeutics. The synthesis of new active substances and eventual identification of those with activity against P. falciparum and T. gondii will represent in itself a contribution to the repertoire of chemotherapeutics, with enormous development potential. Applied research has immediate clinical significance. The introduction of new diagnostic methods (such as molecular diagnostics of malaria) will represent a contribution to the clinical care of these patients in Serbia. Also, in the same sense, knowledge of the genetic variability of T. gondii and P. falciparum strains that are isolated in Serbia will be useful because it will contribute to treatment with a more adequate choice of drugs, but it will also have wider significance because they contribute to knowledge of the molecular map of these organisms at the level of the region, Europe and the world.

Objective: to replace the antimalarial chloroquine (CQ) due to the increase in the number of MDR P.falciparum strains; to develop new tetraoxane antimalarials due to the appearance of significantly reduced clinical efficacy of drugs containing artemisinin derivatives (Nat.Rev.Microbiol 2010,8,272); transform leading non-toxic inhibitors (SMNPIs) of BoNT/A LC into bioavailable inhibitors (low nM region) that will become drug candidates. To develop compounds that could treat botulism caused by botulinum neurotoxin poisoning. The project includes the development of dual inhibitors, antimalarial compounds and botulinum neurotoxin inhibitors. SMNPIs based on the structure of diazachrysene, cholic acid and adamantane have been shown to inhibit CQR P.f. strains with IC50<10nM, as well as to treat mice at doses of 50-80mg/kg/day without toxic effects after necropsy. Another antimalarial, an aminoquinoline steroid derivative, also proved to be a strong BoNT inhibitor: BoNT/A LC IC50=2.20µM;Ki=3.20µM. The project includes the synthesis of new chemotypes and the optimization of current leads discovered by us; potential in vivo candidates will be tested for metabolic stability in liver microsomes. We will apply the methods of modern computational chemistry, the simulation of the behavior of interacting molecules and the calculation of images of the electrostatic potentials of these compounds in different pH environments, applying higher degrees of theory. Scientific collaborations with WRAIR (malaria), USAMRIID (BoNT inhibition), and SAIC-NCI (computational modeling; CRADA contracts and/or joint scientific projects).

Dr Nevena Mihailović-Stanojević, dr Đurđica Jovović, dr Zoran Miloradović, dr Jelica Grujić Milanović, dr Milan Ivanov

University of Belgrade, Institute for Medical Research, Institute of national importance for the Republic of Serbia

The subproject was designed with the aim to explore the possible role of the active components of Thymus serpyllum L. and Urtica dioica L. from Serbia in the prevention and treatment of cardiovascular diseases. In this subproject, the in vivo effects of extracts of Thymus serpyllum L. and Urtica dioica L. on blood pressure, peripheral circulation resistance, lipid peroxidation, and oxidative stress were studied in the model of essential and malignant hypertension in rats with congenital hypertension. These results formed the basis for further research into the chronic effects of biologically active substances from Thymus serpyllum L. and Urtica dioica L. and for their application as dietary supplements in the therapy of cardiovascular diseases.

Dr Đurđica Jovović, dr Zoran Miloradović, dr Nevena Mihailović-Stanojević, dr Jelica Grujić Milanović, dr Milan Ivanov, dr Danijela Karanović, dr Una Jovana Vajić

University of Belgrade, Institute for Medical Research, Institute of national importance for the Republic of Serbia

One of the main objectives of the project was to investigate the effects of natural and synthetic antioxidant substances in hypertension and acute and chronic renal failure. The effects of using olive extract (which contains potent antioxidants) on animal models of essential hypertension and kidney disease were also studied. Part of the project also included testing the beneficial effects of resveratrol, a potent antioxidant molecule isolated from grapes, in models of experimental essential and malignant hypertension. The relationship between the renin-angiotensin system and oxidative stress in the development of post-ischemic acute renal failure and chronic kidney disease was investigated. We used rats with essential hypertension in which we induced acute kidney injury or adriamycin-induced renal glomerulosclerosis and administered angiotensin-2 receptor blockers and synthetic analogues of the enzyme superoxide dismutase. The results of these studies have revealed to us inadequately known mechanisms of action of oxidative stress and the renin-angiotensin system in hypertension, acute renal failure, and chronic kidney disease.

Teodora Dragojević, Tijana Subotički, Miloš Diklić, Olivera Mitrović Ajtić, Vladan Čokić

The aim of this project is to investigate potential involvement of NOS enzymes in the molecular mechanism of action of the chemotherapeutic agent hydroxyurea, which is used for the treatment of myeloproliferative neoplasms, chronic myeloid leukemia, and solid tumors. Obtained results should answer the following scientific questions: 1) if HU activates NOS enzymes via direct interaction or indirectly, 2) if inhibition or reduced protein expression of NOS enzymes at least partially rescues HU-induced proliferation block and apoptosis and, 3) which of the NOS isoforms is involved in these processes? Primary mouse erythroid cells isolated from bone marrow and human erythroleukemic cell lines will be used in this study. The relevance of the results obtained in vitro will be confirmed by in vivo treatment of Nos2- or Nos3- deficient mice. Comprehensive knowledge of the molecular mechanism of HU might help improve its beneficial properties and decrease adverse effects.