Yongneng Zhang
◽
Sotirios D. Zervopoulos
◽
Aristeidis E. Boukouris
◽
Maria Areli Lorenzana‐Carrillo
◽
Bruno Saleme
◽
...
Background
Isolated loss‐of‐function single nucleotide polymorphisms (SNPs) for
SIRT3
(a mitochondrial deacetylase) and
UCP2
(an atypical uncoupling protein enabling mitochondrial calcium entry) have been associated with both pulmonary arterial hypertension (PAH) and insulin resistance, but their collective role in animal models and patients is unknown.
Methods and Results
In a prospective cohort of patients with PAH (n=60), we measured SNPs for both
SIRT3
and
UCP2,
along with several clinical features (including invasive hemodynamic data) and outcomes. We found
SIRT3
and
UCP2
SNPs often both in the same patient in a homozygous or heterozygous manner, correlating positively with PAH severity and associated with the presence of type 2 diabetes and 10‐year outcomes (death and transplantation). To explore this mechanistically, we generated double knockout mice for
Sirt3
and
Ucp2
and found increasing severity of PAH (mean pulmonary artery pressure, right ventricular hypertrophy/dilatation and extensive vascular remodeling, including inflammatory plexogenic lesions, in a gene dose‐dependent manner), along with insulin resistance, compared with wild‐type mice. The suppressed mitochondrial function (decreased respiration, increased mitochondrial membrane potential) in the double knockout pulmonary artery smooth muscle cells was associated with apoptosis resistance and increased proliferation, compared with wild‐type mice.
Conclusions
Our work supports the metabolic theory of PAH and shows that these mice exhibit spontaneous severe PAH (without environmental or chemical triggers) that mimics human PAH and may explain the findings in our patient cohort. Our study offers a new mouse model of PAH, with several features of human disease that are typically absent in other PAH mouse models.