İnsan Yağ Dokusu Mezenşimal Kök Hücrelerinde Notch Sinyal Yolunun Araştırılması

Abstract

ABSTRACT

INVESTIGATION OF THE NOTCH SIGNALING PATHWAY IN HUMAN ADIPOSE DERIVED MESENCHYMAL STEM CELLS

Asım Niyaz Master of Science, Department of Biology Supervisor: Doç.Dr. Ozer Aylin GURPINAR January 2017, 67 pages

Stem cells are specialized cells that have ability to proliferate, self renew and differantiate into various types of cells. Because of this potential they have an important role in tissue repair and treatment. Notch signaling pathway plays key role in cell cycle of vertebrate and invertebrates. Abnormal activation of the notch signaling pathway associated with developmental problems, neurodegenerative diseases and cancer. Notch signaling shows variable biological results on stem cell biology like self renew or differantiation according to different cellular context. Researchers have investigated notch signaling activity on adipose tissue derived mesenchymal stem cells (MSCs), and the results have been variable. Our aim was to investigate changes in the notch signaling pathway activity in different passages of human adipose tissue derived MSCs. Adipose tissue obtained from healthy donors and MSCs were isolated with primary explant culture method. The isolated cells were characterized and passaged (P2, P3, P4, P6, P8 and P10). In order to determine the aging at different passages β- galactosidase levels were measured. Changes of the notch signaling pathway activity at different passages were measure by ELISA. Total Notch1 (receptors located on the cell membrane) and Cleaved Notch1 (the intracellular part of the ruptured receptors indicating that the signaling is active) measured seperately. The results showed that β-galactosidase activity of cells show a significant difference (p<0,05) between adipose derived MSCs (P2, P3, P4, P6, P8 and P10) and control. β-galactosidase activity increased parallel with aging and thus demonstrate the degree of aging of the cells. Total Notch1 and Cleaved Notch1 ELISA results showed statistically significant difference (p<0,05) between different passages of adipose derived MSCs and control, but no difference (p>0,05) between passages. These data showed that adipose derived MSCs express notch receptors and keep this signaling pathway active. As a result, MSCs continued to demonstrate notch signaling pathway activity in different passages, but this activity did not differ significantly between passages. This suggests that for the first ten passages MSCs continue self renewal features.

Keywords: Human, adipose tissue, mesenchymal stem cell, β-Galactosidase, Notch1