ijms-22-09105.pdf

t: Pulmonary arterial hypertension (PAH) is a devastating lung disease characterized by the

progressive obstruction of the distal pulmonary arteries (PA). Structural and functional alteration of

pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) contributes to PA wall

remodeling and vascular resistance, which may lead to maladaptive right ventricular (RV) failure

and, ultimately, death. Here, we found that decreased expression of sarcoplasmic/endoplasmic

reticulum Ca2+ ATPase 2a (SERCA2a) in the lung samples of PAH patients was associated with

the down-regulation of bone morphogenetic protein receptor type 2 (BMPR2) and the activation of

signal transducer and activator of transcription 3 (STAT3). Our results showed that the antiprolifera-

tive properties of SERCA2a are mediated through the STAT3/BMPR2 pathway. At the molecular

level, transcriptome analysis of PASMCs co-overexpressing SERCA2a and BMPR2 identified STAT3

amongst the most highly regulated transcription factors. Using a specific siRNA and a potent pharma-

cological STAT3 inhibitor (STAT3i, HJC0152), we found that SERCA2a potentiated BMPR2 expression

by repressing STAT3 activity in PASMCs and PAECs. In vivo, we used a validated and efficient

model of severe PAH induced by unilateral left pneumonectomy combined with monocrotaline

(PNT/MCT) to further evaluate the therapeutic potential of single and combination therapies using

adeno-associated virus (AAV) technology and a STAT3i. We found that intratracheal delivery of

AAV1 encoding SERCA2 or BMPR2 alone or STAT3i was sufficient to reduce the mean PA pressure

and vascular remodeling while improving RV systolic pressures, RV ejection fraction, and cardiac

remodeling. Interestingly, we found that combined therapy of AAV1.hSERCA2a with AAV1.hBMPR2

or STAT3i enhanced the beneficial effects of SERCA2a. Finally, we used cardiac magnetic resonance

imaging to measure RV function and found that therapies using AAV1.hSERCA2a alone or combined

with STAT3i significantly inhibited RV structural and functional changes in PNT/MCT-induced PAH.

In conclusion, our study demonstrated that combination therapies using SERCA2a gene transfer

with a STAT3 inhibitor could represent a new promising therapeutic alternative to inhibit PAH and

to restore BMPR2 expression by limiting STAT3 activity