The Morrell laboratory is studying the molecular mechanisms underlying pulmonary arterial hypertension. In particular our research is focussed on how mutations in the bone morphogenetic protein type II receptor (BMPR-II), a receptor member of the transforming growth factor-beta superfamily, cause familial pulmonary arterial hypertension (PAH).

Our research is revealing how BMPR-II mutation leads to dysfunctional signalling, gene transcription and vascular cell biology. This work has also revealed a broader role for BMPR-II in angiogenesis, inflammation, iron metabolism and innate immunity.

Our research has suggested new approaches to the rescue of BMPR-II deficiency. These include gene therapy, enhanced BMPR-II transcription and the demonstration that BMPR-II is rapidly degraded by the lysosome. Inhibition of the lysosomal turnover of BMPR-II with agents such as chloroquine increase cell surface BMPR-II and are effective in experimental models of pulmonary hypertension. Loss of BMPR-II is associated with increased activity of other important growth factor pathways including platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) signalling. We have confirmed that inhibitors of these pathways are effective in experimental models of PAH, and PDGF inhibition has now proven beneficial in patients with PAH.

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