Loss of DP1 Aggravates Vascular Remodeling in Pulmonary Arterial Hypertension via mTORC1 Signaling

Am J Respir Crit Care Med. 2020 May 15;201(10):1263-1276. doi: 10.1164/rccm.201911-2137OC.


Rationale: Vascular remodeling, including smooth muscle cell hypertrophy and proliferation, is the key pathological feature of pulmonary arterial hypertension (PAH). Prostaglandin I2 analogs (beraprost, iloprost, and treprostinil) are effective in the treatment of PAH. Of note, the clinically favorable effects of treprostinil in severe PAH may be attributable to concomitant activation of DP1 (D prostanoid receptor subtype 1).Objectives: To study the role of DP1 in the progression of PAH and its underlying mechanism.Methods: DP1 levels were examined in pulmonary arteries of patients and animals with PAH. Multiple genetic and pharmacologic approaches were used to investigate DP1-mediated signaling in PAH.Measurements and Main Results: DP1 expression was downregulated in hypoxia-treated pulmonary artery smooth muscle cells and in pulmonary arteries from rodent PAH models and patients with idiopathic PAH. DP1 deletion exacerbated pulmonary artery remodeling in hypoxia-induced PAH, whereas pharmacological activation or forced expression of the DP1 receptor had the opposite effect in different rodent models. DP1 deficiency promoted pulmonary artery smooth muscle cell hypertrophy and proliferation in response to hypoxia via induction of mTORC1 (mammalian target of rapamycin complex 1) activity. Rapamycin, an inhibitor of mTORC1, alleviated the hypoxia-induced exacerbation of PAH in DP1-knockout mice. DP1 activation facilitated raptor dissociation from mTORC1 and suppressed mTORC1 activity through PKA (protein kinase A)-dependent phosphorylation of raptor at Ser791. Moreover, treprostinil treatment blocked the progression of hypoxia-induced PAH in mice in part by targeting the DP1 receptor.Conclusions: DP1 activation attenuates hypoxia-induced pulmonary artery remodeling and PAH through PKA-mediated dissociation of raptor from mTORC1. These results suggest that the DP1 receptor may serve as a therapeutic target for the management of PAH.

Keywords: DP1 receptor; hypertrophy and proliferation; mTOR signaling; pulmonary arterial hypertension; pulmonary artery smooth muscle cell.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antihypertensive Agents / pharmacology
  • Cell Proliferation / drug effects
  • Cell Proliferation / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Down-Regulation
  • Epoprostenol / analogs & derivatives
  • Epoprostenol / pharmacology
  • Humans
  • Hypertrophy
  • Hypoxia / metabolism*
  • Immunosuppressive Agents / pharmacology
  • Mechanistic Target of Rapamycin Complex 1 / antagonists & inhibitors
  • Mechanistic Target of Rapamycin Complex 1 / metabolism*
  • Mice
  • Mice, Knockout
  • Muscle, Smooth, Vascular / drug effects
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / metabolism
  • Myocytes, Smooth Muscle / pathology
  • Pulmonary Arterial Hypertension / drug therapy
  • Pulmonary Arterial Hypertension / genetics*
  • Pulmonary Arterial Hypertension / metabolism
  • Pulmonary Artery
  • RNA, Messenger / metabolism
  • Rats
  • Receptors, Immunologic / genetics*
  • Receptors, Prostaglandin / genetics*
  • Sirolimus / pharmacology
  • Vascular Remodeling / genetics*


  • Antihypertensive Agents
  • Immunosuppressive Agents
  • RNA, Messenger
  • Receptors, Immunologic
  • Receptors, Prostaglandin
  • Epoprostenol
  • Mechanistic Target of Rapamycin Complex 1
  • Cyclic AMP-Dependent Protein Kinases
  • treprostinil
  • Sirolimus
  • prostaglandin D2 receptor