title: Gene therapy by targeted adenovirus-mediated knockdown of pulmonary endothelial Tph1 attenuates hypoxia-induced pulmonary hypertension.
abstract: Serotonin is produced by pulmonary arterial endothelial cells (PAEC) via tryptophan hydroxylase-1 (Tph1). Pathologically, serotonin acts on underlying pulmonary arterial cells, contributing to vascular remodeling associated with pulmonary arterial hypertension (PAH). The effects of hypoxia on PAEC-Tph1 activity are unknown. We investigated the potential of a gene therapy approach to PAH using selective inhibition of PAEC-Tph1 in vivo in a hypoxic model of PAH. We exposed cultured bovine pulmonary arterial smooth muscle cells (bPASMCs) to conditioned media from human PAECs (hPAECs) before and after hypoxic exposure. Serotonin levels were increased in hypoxic PAEC media. Conditioned media evoked bPASMC proliferation, which was greater with hypoxic PAEC media, via a serotonin-dependent mechanism. In vivo, adenoviral vectors targeted to PAECs (utilizing bispecific antibody to angiotensin-converting enzyme (ACE) as the selective targeting system) were used to deliver small hairpin Tph1 RNA sequences in rats. Hypoxic rats developed PAH and increased lung Tph1. PAEC-Tph1 expression and development of PAH were attenuated by our PAEC-Tph1 gene knockdown strategy. These results demonstrate that hypoxia induces Tph1 activity and selective knockdown of PAEC-Tph1 attenuates hypoxia-induced PAH in rats. Further investigation of pulmonary endothelial-specific Tph1 inhibition via gene interventions is warranted.
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, College of Medical, Veterinary and Life Sciences, West Medical Building, University of Glasgow, Glasgow, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Morecroft
authors.forename: Katie
authors.initials: K
authors.lastname: White
authors.forename: Paola
authors.initials: P
authors.lastname: Caruso
authors.forename: Margaret
authors.initials: M
authors.lastname: Nilsen
authors.forename: Lynn
authors.initials: L
authors.lastname: Loughlin
authors.forename: Raul
authors.initials: R
authors.lastname: Alba
authors.forename: Paul N
authors.initials: PN
authors.lastname: Reynolds
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Danilov
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Baker
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Maclean
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002417:Cattle; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D065627:Familial Primary Pulmonary Hypertension; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D000860:Hypoxia / Q000503:physiopathology*; D051381:Rats; D014365:Tryptophan Hydroxylase / Q000235:genetics / Q000378:metabolism*
chemical_list: C497467:TPH1 protein, human; D014365:Tryptophan Hydroxylase