Differentially Expressed Proteins in Pulmonary Endothelial Cells in Chronic Thromboembolic Pulmonary Hypertension

Rationale: Dysfunction of endothelial cells is believed to be involved in the development of chronic thromboembolic pulmonary hypertension (CTEPH). The identification of the molecular mechanisms underlying endothelial dysfunction is crucial to the understanding of the disease and to the expansion of novel therapeutic strategies. The objective of this study was to identify the differentially regulated proteins associated with the vascular dysfunctionality of CTEPH. Patient derived endothelial cells provides a unique opportunity to analyze the precise mechanisms involved in the pathophysiology of the disease. Methods: We analyzed endothelial cells isolated from specimens obtained in pulmonary endarterectomy (PEA)(CTEPH-ECs) in 4 patients. Altered protein expression profiling in combination with gene ontology, network and pathway analysis was employed by using the mass spectrometry based label-free quantification approach to explore the molecular proceedings. Moreover, the status of few differentially expressed protein patterns were also determined at mRNA level by using the real-time PCR experiments. The differentially regulated proteins in CTEPH-ECs were identified against the human pulmonary artery endothelial cells (HPAE) as a control. All data were statistically analyzed using the paired t-test and the p value of <0.05 was considered as significance. Results: A total of 1725 proteins were identified and quantified. Significant variations were observed between control and CTEPH-ECs. We identified 46 statistically significant differentially regulated proteins. We found 12 and 4 unique proteins in CTEPH-ECs and HPAE cells, respectively. The gene-annotation enrichment analysis exposed the association of numerous biological processes, cellular component and molecular functions. The analysis using bioinformatic tools revealed the presence of metabolism, interleukin-4 and 13 signaling, biological oxidations, cytokine signaling in immune system, hemostasis and oxidative stress induced senescence pathways in the dysfunctional CTEPH-ECs. The expression pattern of few differentially regulated genes was validated at transcriptome level. Conclusions: This study provided a differentially expressed proteomic profile, biological processes, molecular functions and network pathways associated with the endothelial dysfunction in CTEPH. Further studies should identify the contribution of dysregulated proteins to CTEPH development. This abstract is funded by: H2020 Marie Skłodowska- Curie Actions, Innovative Training Network MOGLYNET, N. 675527. SEPAR (18/2013, 164/2016) SOCAP; Fundación Contra la Hipertensión Pulmonar and Fondo de Investigaciones Sanitarias (PI15/00582).