DHEA decreases HIF-1α accumulation under hypoxia in human pulmonary artery cells: Potential role in the treatment of pulmonary arterial hypertension

Damage-associated molecular patterns, such as HMGB1 (high mobility group box 1), play a well-recognized role in the development of pulmonary arterial hypertension (PAH), a progressive fatal disease of the pulmonary vasculature. However, the contribution of the particular type of vascular cells, type of cell death, or the form of released HMGB1 in PAH remains unclear. Moreover, although male patients with PAH show a higher level of circulating HMGB1, its involvement in the severe PAH phenotype reported in males is unknown. In this study, we aimed to investigate the sources and active forms of HMGB1 released from damaged vascular cells and their contribution to the progressive type of PAH in males. Our results showed that HMGB1 is released by either pulmonary artery human endothelial cells or human pulmonary artery smooth muscle cells that underwent necrotic cell death, although only human pulmonary artery smooth muscle cells produce HMGB1 during apoptosis. Moreover, only human pulmonary artery smooth muscle cell death induced a release of dimeric HMGB1, found to be mitochondrial reactive oxygen species dependent, and TLR4 (toll-like receptor 4) activation. The modified Sugen/Hypoxia rat model replicates the human sexual dimorphism in PAH severity (right ventricle systolic pressure in males versus females 54.7±2.3 versus 44.6±2 mm Hg). By using this model, we confirmed that necroptosis and necrosis are the primary sources of circulating HMGB1 in the male rats, although only necrosis increased circulation of HMGB1 dimers. Attenuation of necrosis but not apoptosis or necroptosis prevented TLR4 activation in males and blunted the sex differences in PAH severity. We conclude that necrosis, through the release of HMGB1 dimers, predisposes males to a progressive form of PAH.

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Unraveling endothelin-1 induced hypercontractility of human pulmonary artery smooth muscle cells from patients with pulmonary arterial hypertension

PLoS ONE ◽

10.1371/journal.pone.0195780 ◽

2018 ◽

Vol 13 (4) ◽

pp. e0195780 ◽

Cited By ~ 6

Author(s):

Jamie L. Wilson ◽

Rod Warburton ◽

Linda Taylor ◽

Deniz Toksoz ◽

Nicholas Hill ◽

...

Keyword(s):

Smooth Muscle ◽

Pulmonary Arterial Hypertension ◽

Pulmonary Artery ◽

Arterial Hypertension ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Endothelin 1 ◽

Pulmonary Arterial ◽

Pulmonary Artery Smooth Muscle ◽

Human Pulmonary Artery

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Extracellular matrix degradation pathways and fatty acid metabolism regulate distinct pulmonary vascular cell types in pulmonary arterial hypertension

Pulmonary Circulation ◽

10.1177/2045894021996190 ◽

2021 ◽

Vol 11 (1) ◽

pp. 204589402199619

Author(s):

Sharon Mumby ◽

F. Perros ◽

C. Hui ◽

B.L. Xu ◽

W. Xu ◽

...

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Pulmonary Arterial Hypertension ◽

Pulmonary Artery ◽

Arterial Hypertension ◽

Cell Types ◽

Microvascular Endothelial Cells ◽

Pulmonary Arterial ◽

Pulmonary Artery Smooth Muscle ◽

Human Pulmonary Artery

Pulmonary arterial hypertension describes a group of diseases characterised by raised pulmonary vascular resistance, resulting from vascular remodelling in the pre-capillary resistance arterioles. Left untreated, patients die from right heart failure. Pulmonary vascular remodelling involves all cell types but to date the precise roles of the different cells is unknown. This study investigated differences in basal gene expression between pulmonary arterial hypertension and controls using both human pulmonary microvascular endothelial cells and human pulmonary artery smooth muscle cells. Human pulmonary microvascular endothelial cells and human pulmonary artery smooth muscle cells from pulmonary arterial hypertension patients and controls were cultured to confluence, harvested and RNA extracted. Whole genome sequencing was performed and after transcript quantification and normalisation, we examined differentially expressed genes and applied gene set enrichment analysis to the differentially expressed genes to identify putative activated pathways. Human pulmonary microvascular endothelial cells displayed 1008 significant ( p ≤ 0.0001) differentially expressed genes in pulmonary arterial hypertension samples compared to controls. In human pulmonary artery smooth muscle cells, there were 229 significant ( p ≤ 0.0001) differentially expressed genes between pulmonary arterial hypertension and controls. Pathway analysis revealed distinctive differences: human pulmonary microvascular endothelial cells display down-regulation of extracellular matrix organisation, collagen formation and biosynthesis, focal- and cell-adhesion molecules suggesting severe endothelial barrier dysfunction and vascular permeability in pulmonary arterial hypertension pathogenesis. In contrast, pathways in human pulmonary artery smooth muscle cells were mainly up-regulated, including those for fatty acid metabolism, biosynthesis of unsaturated fatty acids, cell–cell and adherens junction interactions suggesting a more energy-driven proliferative phenotype. This suggests that the two cell types play different mechanistic roles in pulmonary arterial hypertension pathogenesis and further studies are required to fully elucidate the role each plays and the interactions between these cell types in vascular remodelling in disease progression.

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LRP1 Deficiency in Vascular SMC Leads to Pulmonary Arterial Hypertension That Is Reversed by PPARγ Activation

Circulation Research ◽

10.1161/circresaha.119.315088 ◽

2019 ◽

Vol 124 (12) ◽

pp. 1778-1785 ◽

Cited By ~ 8

Author(s):

Laurent Calvier ◽

Philippe Boucher ◽

Joachim Herz ◽

Georg Hansmann

Keyword(s):

Growth Factor ◽

Pulmonary Arterial Hypertension ◽

Pulmonary Artery ◽

Arterial Hypertension ◽

Main Pulmonary Artery ◽

Tissue Growth ◽

Pulmonary Vasculature ◽

Pparγ Agonist ◽

Pulmonary Arterial ◽

Human Pulmonary Artery

Rationale: Arterial remodeling—a hallmark of many cardiovascular pathologies including pulmonary arterial hypertension (PAH)—is regulated by TGFβ1 (transforming growth factor-β1)–TGFβ receptors and the antagonistic, vasoprotective BMPR2 (bone morphogenetic protein receptor 2)–PPARγ (peroxisome proliferator–activated receptor-γ) axis. However, it is unclear which factors drive detrimental TGFβ1 pathways in the hypertensive pulmonary vasculature. Objective: We hypothesized that LRP1 (low-density lipoprotein receptor–related protein 1) expression is decreased in PAH, leading to enhancement (disinhibition) of TGFβ1 signals and that the PPARγ agonist pioglitazone can restore vascular homeostasis and prevent PAH resulting from LRP1 deletion in vascular smooth muscle cells (SMCs). Methods and Results: Targeted deletion of LRP1 in vascular SMC (smLRP1 −/− ) in mice disinhibited TGFβ1–CTGF (connective tissue growth factor) signaling, leading to spontaneous PAH and distal pulmonary arterial muscularization as assessed by closed-chest cardiac catheterization and anti-αSMA staining. Pioglitazone inhibited the canonical TGFβ1–CTGF axis in human pulmonary artery SMC and smLRP1 −/− main pulmonary artery (CTGF and NOX4) and reversed PAH in smLRP1 −/− mice. TGFβ1 boosted pSmad3 in PASMC from smLRP1 −/− mice versus controls. Pioglitazone-activated PPARγ binds to Smad3 in human pulmonary artery SMC (coimmunoprecipitation), thereby blocking its phosphorylation and overriding LRP1 deficiency. Finally, mRNA and protein expression of LRP1 was decreased in pulmonary plexiform lesions of patients with end-stage idiopathic PAH (laser capture microdissection, qPCR, and immunohistochemistry). Downregulation of LRP1 protein was also demonstrated in explanted PASMC from patients with PAH and accompanied by enhanced TGFβ1–pSmad3–CTGF signaling and increased TGFβ1–induced PASMC proliferation that was prevented by pioglitazone. Conclusions: Here, we identify LRP1 as an integrator of TGFβ1–mediated mechanisms that regulate vascular remodeling in mice and clinical PAH and PPARγ as a therapeutic target that controls canonical TGFβ1 pathways. Hence, pharmacologic PPARγ activation represents a promising new therapy for patients with PAH who lack the vasoprotective LRP1 in vascular SMC.

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