Comparison of lung proteome profiles in two rodent models of pulmonary arterial hypertension

We studied the lung proteome changes in two widely used models of pulmonary arterial hypertension (PAH): monocrotaline (MCT) injection and chronic hypoxia (CH); untreated rats were used as controls (n = 6/group). After 28 days, invasive right ventricular systolic pressure (RVSP) was measured. Lungs were immunostained for alpha-smooth muscle actin (alphaSMA). 2-DE (n = 4/group) followed by nano-LC-MS/MS was applied for protein identification. Western blotting was used additionally if possible. RVSP was significantly increased in MCT- and CH-rats (MCT 62.5 +/- 4.4 mmHg, CH 62.2 +/- 4.1 mmHg, control 25.0 +/- 1.7 mmHg, p<0.001). This was associated with an increase of alphaSMA positive vessels. In both groups, there was a significantly increased expression of proteins associated with the contractile apparatus (diphosphoHsp27 (p<0.001), Septin2 (p<0.001), F-actin capping protein (p<0.01), and tropomyosin beta (p<0.02)). In CH, proteins of the nitric oxide (Hsc70; p = 0.002), carbon monoxide (biliverdin reductase; p = 0.005), and vascular endothelial growth factor (VEGF) pathway (annexin 3; p<0.001) were significantly increased. In MCT, proteins involved in serotonin synthesis (14-3-3; p = 0.02), the enhanced unfolded protein response (ERp57; p = 0.02), and intracellular chloride channels (CLIC 1; p = 0.002) were significantly elevated. Therefore, MCT- and CH-induced vasoconstriction and remodeling seemed to be mediated via different signaling pathways. These differences should be considered in future studies using either PAH model.