Molecular Sciences II.
Dr. Janka Borbála Gém / Semmelweis University - Department of Physiology
Angiotensin II (AngII) is an octapeptide hormone which performs most of its effects via angiotensin II type 1 receptor (AT1R) stimulation. AngII causes fast vasoconstriction in vascular smooth muscle cells (VSMCs) but the stimulation has numerous long term-effects as well, such as gene expression changes, increased proliferation and migration. The long-term actions are essential in the development of AngII related pathological conditions, such as vascular remodelling, hypertension or atherosclerosis. It is already known that the transactivation of epidermal growth factor receptor (EGFR) and other receptor tyrosine-kinases by AT1R have an important role in forming these long-term effects.
In this study, we wanted to explore more deeply the role of AT1R transactivated tyrosine-kinase receptors and non-receptor tyrosine-kinases in the physiological and pathophysiological long-term effects of AngII.
We used primary VSMCs isolated from the aotra thoracalis of rats in our experiments. The cells were exposed to different tyrosine-kinase inhibitor treatments before hormonal stimulations to examine which ones of these enzymes are involved in AngII- induced long-term effects. Gene expression changes were mainly measured by quantitative real-time PCR, focusing on genes that had been proven to be significantly upregulated by AngII stimulation in VSMCs with an Affymetrix gene-chip assay, namely dual-specificity-phosphatase (DUSP) 5, 6 and 10 isoforms that are important regulators of mitogen activated protein kinase (MAPK) cascades. We found that dasatinib, a Bcr-Abl and Src kinase family inhibitor effectively reduced AngII induced gene expressional changes. Furthermore, we demonstrated in Western-blot analysis that dasatinib significantly reduces AngII caused p38 MAPK activation, which can provide useful information about the role p38 MAPK in AngII-induced long-term effects.
To sum up, our research aims to characterize more specifically the molecular background of cardiovascular diseases related to exaggerated AngII effect and may reveal potential targets in the future treatments of these pathological conditions.
This work was supported by the Hungarian National Research, Development and Innovation Fund (NKFI K116954, NVKP_16-1-2016-0039 and VEKOP-2.3.2-16-2016-00002).