student research day - Case Western Reserve University School of ...

Monica Reddy
The Unfolded Protein Response is Activated in Severe
Pulmonary Artery Hypertension
Monica Reddy, Leah Staskiewicz, Laura Sanders, Lisa Mettler, Kelley Colvin, D. Dunbar Ivy, Michael E. Yeager
Pulmonary Hypertension
University of Colorado School of Medicine
The origins of the insult(s) that serve as the genesis of PAH pathobiology have long been under intense
investigation. Viruses, ingestion of diet pills, high-altitude, and chronic thromboembolic disease have all been
implicated. We hypothesized that, regardless of etiology, the lung vasculature is severely stressed secondary to
these conditions. In many conditions of cell or tissue stress, the unfolded protein response (UPR) is activated and
plays a number of important roles in both normal and disease processes. We hypothesized that patients with
severe pulmonary artery hypertension (PAH) exhibit an underlying protein folding derangement. We therefore
investigated whether the UPR is activated in human tissue and in two mechanistically distinct animal models with
severe PAH. Further, we sought to examine the role of acute and chronic hypoxia in the generation of UPR in
pulmonary vascular cell cultures. Tissue samples from both animal models and human models were obtained and
examined using immunohistochemistry, immunoblot analysis, cell cultures, and RNA analysis. Antibodies BiP, IRE-
1, and ATF-6 were used as markers of UPR. We found that some groups in both rat models’ tissue demonstrated
tight correlation with the human tissue results with respect to expression of BiP, ATF-6, Hrd1, and IRE-1. In a
hypoxic state, BiP, IRE1, ATF6, and Hrd1 are highly expressed at 48 hours of hypoxia (Figure 5) as measured by
immunoblot and immunofluorescence, as well as XBP RTPCR.
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