prvi kongres hrvatskih znanstvenika iz domovine i inozemstva - HATZ

PRVI KONGRES HRVATSKIH ZNANSTVENIKA IZ DOMOVINE I INOZEMSTVAZagreb - Vukovar, 15. - 19. studenog 2004.P - 26EFFECTS OF IMMUNOMODULATORY DRUGS ON GALECTIN-3S. Dabelić, J. Dumić and M. FlögelFaculty of Pharmacy and Biochemistry, University of Zagreb, CroatiaGalectin-3, a 29-32 kDa β-galactoside binding lectin, is implicated in many biologicalprocesses, (e.g. growth regulation, pre-mRNA splicing, cell differentiation, neoplastictransformation and tumor metastasis). It plays a key role in immune responses bymodulating T-cell apoptosis, proliferation, cell adhesion, chemotaxis and synthesis ofinflammatory mediators such as cytokines, nitric oxide and prostaglandines. Galectin-3expression is influenced by various stimuli but the precise regulatory mechanisms arenot yet elucidated. In our previous studies we showed the involvement of the NF-kappaBand AP-1 transcription factors in regulation of galectin-3 expression. It was also shownthat galectin-3 expression in macrophages is regulated by Ras/MAP kinase signallingpathway. The mentioned transcription factors and signalling pathway are stronglyinfluenced by many anti-inflammatory drugs. The aim of our study was to determine theeffects of steroid (hydrocortisone - HC and dexamethasone - Dex) as well as non-steroidimmunomodulatory drugs (aspirin – Asp and indomethacin - Ind) on the expression ofgalectin-3 both on the mRNA and protein level. The human monocytic cell line THP-1was exposed to various concentrations of Asp (0.1, 0.5, 1 and 2 mM), Ind (0.1, 1, 5 and10 µM), HC (0.1, 1, 5 and 10 µM) and Dex (0.1, 1, 10 and 100 nM) during 1, 3, 5, 24, 48or 72 hrs. The target gene mRNA level is evaluated using relative RT-PCR method andGeneScan analysis software. The results showed that all concentrations of applied drugshalved the galectin-3 mRNA level already after 1 h of exposure (except 0.1 mM aspirinwhich showed that effect after 24 h) and that the level of mRNA continued to decreaseduring time, and was only 4-30% of the initial value after 72 h. Surprisingly, the proteinexpression measured by chemiluminescent-western blot analysis didn’t follow the samepattern – the decrease was observed only after 48 and 72 h of exposure, when thegalectin-3 level fell on 70% and 50% of the initial value, respectively.Presented on:9 th Annual Meeting of The Society of Glycobiology – US/Japan Glyco 2004,Honolulu, USA, November 17-20, 2004.Principal Investigator : Dr.sc. Mirna Flögel-MršićProject No. 000661128