Description
- Abstract:
- Aberrant endothelial cell (EC) proliferation plays an important role in the vascular remodeling observed in Pulmonary Arterial Hypertension (PAH). Anoctamin-1 (Ano1), a calcium activated chloride channel (CaCC), has been implicated in the regulation of cell proliferation in several cancer studies. We initially set out to confirm expression and localization of Ano1 in pulmonary ECs. Next we sought to investigate the role of altered Ano1 activity in regulating the proliferative potential of pulmonary ECs. The underlying rationale was to assess whether Ano1 could serve as a molecular target for the reversal of hyperproliferative ECs associated with PAH. The findings of this dissertation are summarized as follows: 1. Ano1 is expressed in Rat Lung Microvascular ECs (RLMVECs), Human Pulmonary Endothelial Cells (HPAECs), isolated control and IPAH patient ECs. Additionally, we utilized a rat model of PAH known as Sugen-Hypoxia (SUH). We demonstrated that Ano1 levels are elevated in isolated ECs from lungs of SUH rats when compared to controls. In line with this finding, we also demonstrate that Ano1 levels in lung ECs from patients with PAH are increased when compared to lung ECs from control patients. This is the first study identifying Ano1 expression in pulmonary ECs and that Ano1 is increased in settings of PAH. 2. Ano1 is localized to the membranous and mitochondrial fractions of RLMVECs. We also demonstrated that activation of Ano1 resulted in loss of mitochondrial membrane potential (ΔΨm) and increased mitochondrial ROS (mtROS). 3. Activation of Ano1 resulted in p38-dependent apoptosis and caspase-3 activation. Activation of Ano1 with Eact, a small molecule activator, resulted in caspase-3 activation, mediated by increased mtROS and p38 phosphorylation. 4. Activation of Ano1 in IPAH ECs resulted in reduced cell number when compared to control ECs. Underlying this reduction in cell number was an increase in caspase-3 cleavage when compared to control ECs. Blocking mtROS and Ano1 by using MitoTEMPO and DIDS, respectively, attenuated Eact-mediated decreases in IPAH EC number, confirming that the mechanism we established in RLMVEC is relevant in lung ECs from IPAH patients as well.
- Notes:
- Thesis (Ph.D. -- Brown University (2016)
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Citation
Allawzi, Ayed M.,
"Activation of Ano1 is Associated with Apoptosis of Pulmonary Endothelial Cells: Implications for Pulmonary Arterial Hypertension"
(2016).
Molecular Pharmacology, Physiology, and Biotechnology Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0BG2MDK
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Molecular Pharmacology, Physiology, and Biotechnology Theses and Dissertations
Theses and Dissertations for the Molecular Pharmacology, Physiology, and Biotechnology department....