Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Thekkekara Puthenparampil, H.
Extracellular Matrix Components in Idiopathic Pulmonary Arterial Hypertension: a Non-coding Perspective
PhD-Studium (Doctor of Philosophy); Humanmedizin; [ Dissertation ] Medizinische Universität Graz; 2022. pp. 115
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Jandl Katharina
- Kwapiszewska-Marsh Grazyna
- Olschewski Andrea
- Altmetrics:
- Abstract:
- Extracellular matrix (ECM) remodelling of the distal pulmonary arteries occurs early in idiopathic pulmonary arterial hypertension (IPAH) and is a core aspect of its pathologic development. The resulting increased ECM turnover provides a permissive environment that favours cell proliferation, migration and resistance to apoptosis, and thereby strongly contributes to the vascular stiffness in IPAH. The rather newly identified players in IPAH are the long non-coding RNAs (lncRNAs). Central biologic importance has been attributed to the lncRNAs recently, while less is known about them in the context of ECM remodelling in IPAH. By applying transcriptomic analysis on laser-capture microdissected small pulmonary arteries, we characterized the differential gene expression profile in IPAH that is shaped by coding as well non-coding genes. Our findings identifed metabolic, cytoskeletal, apoptotic and proliferative processes as key signalling pathways perturbed in IPAH, and identifed the ECM as the core cellular component that is affected in the disease. Focusing further on the ECM, we described the expression of ECM related components in IPAH. Demonstrating the significance of lncRNAs in IPAH, we validated the upregulation of the lncRNAs TUSC8 and PAXIP1-AS1 in IPAH and detailed the functional involvement of PAXIP1-AS1 and intrinsic molecular mechanisms in pulmonary artery smooth muscle cells (PASMC) by applying a siRNA-mediated knockdown approach. We reported the markedly reduced proliferative and migrative behaviour, and elevated pro-apoptotic events in PASMC after PAXIP1-AS1 knockdown. Transcriptomic analysis identified the basement membrane as the most affected cellular component after PAXIP1-AS1 knockdown and revealed a regulatory mechanism of the lncRNA via the focal adhesion machinery where PAXIP1-AS1 acts via its downstream target paxillin. Our results showed the upregulation of the prominent basement membrane collagen COL18A1 in IPAH and confirmed the anti-proliferative effects of its proteolytic product endostatin. Finally, we found first indications that suggest PAXIP1-AS1 overexpression does not influence endostatin release in pulmonary artery endothelial cells in our experimental setup. Taken together, we were able to identify an entanglement of the lncRNAs with the ECM in the setting of IPAH and revealed PAXIP1-AS1 as a potent regulator of smooth-muscle cell function acting via its downstream effector protein paxillin.