Analysis of transcriptome in hypoxia(7d)-exposed lungs upon KO of Nfat5 in ECs

Chronic hypoxic stress stimulates lung endothelial cells to promote vascular remodeling processes, which - in the long run - increase the resistance of pulmonary arteries. While several molecular determinants promoting these maladaptive changes have been delineated, their transcriptional regulation is not well studied. In this context, we revealed that hypoxia activates nuclear factor of activated T-cells 5 (NFAT5/TonEBP) in murine lung endothelial cells (MLECs) - a transcription factor that regulates the adjustment of the cellular transcriptome to cope with osmotic, biomechanical or metabolic environmental stressors. Here, we studied the functional relevance of NFAT5 for the control of endothelial hypoxic stress responses in the lung. Genetic ablation of Nfat5 in endothelial cells did not evoke any obvious phenotypic alterations under normoxia. However, microarray-based transcriptome analyses of lung tissue revealed significant alterations 7 but not 21 days after exposure to normobaric hypoxia (10% O2). RNA was isolated from lungs of 4 male/female Nfat5fl/fl (control) and Nfat5(EC)-/- (EC-specific KO) mice exposed to hypoxia for 7 days. Lung preparations containing contaminating tissue (e.g. thymus) or showing inadequate (expression) responses to hypoxia were excluded from further analyses.