Browsing by Subject "tymosiini beta4"

Angiogenesis may be regarded as one of the most important phenomena involved in basic physiology as well as in numerous pathological conditions. Angiogenesis is a multistep process involving the balance of pro- and con-angiogenic factors. Several studies have suggested that angiogenesis is regulated in vitro and in vivo by peptides thymosin ȕ4 (Tȕ4) and tetrapeptide Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline). There are also studies supporting the view that Ac-SDKP, a peptide fragment is released from the proline-containing C-terminus of Tȕ4 (43-mer) by hydrolyzing prolyl oligopeptidase (POP). POP is a widely existing serine protease cleaving oligopeptides of no longer than 30 amino acids. Thus, Tȕ4 should first be cleaved into a shorter peptide by some other, yet unknown peptidase. POP has been mostly studied in memory and learning disorders as well as in neurodegenerative diseases. The true physiological character of POP is still unresolved. In this Master's thesis, the associations of the factors involved in angiogenesis are reviewed in the literature part as well as the character, presence and function of the angiogenic molecules 7ȕ4, Ac-SDKP and POP. In the experimental part attempts were made to find whether POP and Tȕ4 increase Ac-SDKP formation and capillary tube network and consequently, whether the POP activity, tetrapeptide and capillary formation could be inhibited by the proline-spesific POP inhibitor KYP-2047. The study had two phases. The first phase included POP activity and Ac-SDKP measurements(time period 0-180 min) with Wistar rat kidney homogenates. Study groups were 0,1 and 0,5 µM KYP-2047 (+2 µM Tȕ4), 1:20 (0.625 µM) human recombinant POP (+ 2 µM Tȕ4), 2 µM 7ȕ4 (pos. control) and raw homogenate (neg. control). The second phase involved the study of capillary formation (time period 0-180 min) with primary endothelial HUVECs on a 48-well plate seeded with 50 000 cells/well on an extracellular membrane mimicking MatrigelTM Matrix dissolved in DMEM. Study groups treated with fetal bovine serum and antibiotics were 5 and 10 µM KYP-2047 (+4 µM Tȕ4), 1:20 (0.625 µM) human recombinant POP (+4 µM Tȕ4)4 µM Tȕ4 (pos. control) and DMEM (neg. control). The wells were cultured and capillary formation photographed with a light microscope using a digital camera. All experiments were repeated four times, and each study group in wells was measured in triplicate. Enclosed capillaries were counted manually and statistical tests were performed. 7ȕ4 along with POP participated in the formation of AC-SDKP in the kidney homogenates. Cultures of primary endothelial cells on Matrigel resulted in clear capillary formation in Tȕ4 and POP groups. KYP-2047 had a strong POP-inhibitory activity on antiangiogenesis throughout the study resulting. Obviously, underlying mechanisms of angiogenesis and the function of the interaction between POP, Tȕ4 and Ac-SDKP in capillary formation require further studies.