Imbalance of NFATc2 and KV1.5 Expression in Rat Pulmonary Vasculature of Nitrofen-Induced Congenital Diaphragmatic Hernia

Abstract

Aim of the Study Nuclear factor of activated T-cell (NFATc2), a Ca²⁺/calcineurin-dependent transcription factor, is reported to be activated in human and animal pulmonary hypertension (PH). KV1.5, a voltage-gated K⁺ (KV) channel, is expressed in pulmonary artery smooth muscle cells (PASMC) and downregulated in PASMC in patients and animals with PH. Furthermore, activation of NFATc2 downregulates expression of KV1.5 channels, leading to excessive PASMC proliferation. The aim of this study was to investigate the pulmonary vascular expression of NFATc2 and KV1.5 in rats with nitrofen-induced congenital diaphragmatic hernia (CDH).

Materials and Methods After ethical approval, time-pregnant Sprague–Dawley rats received nitrofen or vehicle on gestational day 9 (D9). When sacrificed on D21, the fetuses (n = 22) were divided into CDH and control groups. Using quantitative real-time polymerase chain reaction and western blotting, we determined the gene and protein expression of NFATc2 and KV1.5. Confocal microscopy was used to detect both proteins in the pulmonary vasculature.

Results Relative mRNA levels of NFATc2 were significantly upregulated and KV1.5 levels were significantly downregulated in CDH lungs compared with controls (p < 0.05). Western blotting confirmed the imbalanced pulmonary protein expression of both proteins. An increased pulmonary vascular expression of NFATc2 and a diminished expression of KV1.5 in CDH lungs compared with controls were seen in confocal microscopy.

Conclusions This study demonstrates for the first time an altered gene and protein expression of NFATc2 and KV1.5 in the pulmonary vasculature of nitrofen-induced CDH. Upregulation of NFATc2 with concomitant downregulation of KV1.5 channels may contribute to abnormal vascular remodeling resulting in PH in this model.

Keywords

congenital diaphragmatic hernia - nitrofen - NFATc2 - KV1.5 - pulmonary hypertension

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