Dataset Information

Galectin-3 Mediates Endothelial-to-Mesenchymal Transition in Pulmonary Arterial Hypertension.

ABSTRACT: Galectin-3 (Gal-3) is highly expressed in fibrotic tissue related to diverse etiologies. endothelial-to-mesenchymal transition (EndoMT), A less well studied phenomenon serves as a critical process in pulmonary vascular remodeling associated with the development of pulmonary arterial hypertension (PAH). EndoMT is hypothesized to contribute to the over-proliferation of ?SMA positive cells. We aim to investigate the potential role of Gal-3 in regulating EndoMT in PAH. We observed an upregulation in both Gal-3 and ?SMA expression in the monocrotaline (MCT) and Hypoxia PAH model, accompanied with intimal thickening. For more profound vascular remodeling and endothelial layer lesion in former model, we employed Gal-3 knockdown and overexpression lentivirus methodology to the MCT rats to determine the mechanisms underlying abnormal endothelial cell transition in PAH. PAH was evaluated according to right ventricular systolic pressure, right heart hypertrophy and pulmonary artery remodeling. A reduction in Gal-3 was protective against the development of PAH, while Gal-3 upregulation aggravated pulmonary vascular occlusion. In addition, Gal-3 deficiency suppressed pulmonary vascular cell proliferation and macrophage infiltration. Finally, we revealed that in endothelial cells treated with tumor necrosis factor ? and hypoxia (representing an in vitro model of PAH), inhibition of Gal-3 by siRNA was able to abolish the associated upregulation of ?SMA. These observations suggesting Gal-3 serves as a critical mediator in PAH by regulating EndoMT. Inhibition of Gal-3 may represent a novel therapeutic target for PAH treatment.

SUBMITTER: Li T

PROVIDER: S-EPMC6675525 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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Galectin-3 Mediates Endothelial-to-Mesenchymal Transition in Pulmonary Arterial Hypertension.

Li Tangzhiming T Zha Lihuang L Luo Hui H Li Suqi S Zhao Lin L He Jingni J Li Xiaohui X Qi Qiangqiang Q Liu Yuwei Y Yu Zaixin Z

Aging and disease 20190801 4

Galectin-3 (Gal-3) is highly expressed in fibrotic tissue related to diverse etiologies. endothelial-to-mesenchymal transition (EndoMT), A less well studied phenomenon serves as a critical process in pulmonary vascular remodeling associated with the development of pulmonary arterial hypertension (PAH). EndoMT is hypothesized to contribute to the over-proliferation of αSMA positive cells. We aim to investigate the potential role of Gal-3 in regulating EndoMT in PAH. We observed an upregulation in ...[more]

PMID: 31440380

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Project description:Aims:The pathogenic mechanisms of pulmonary arterial hypertension (PAH) remain unclear, but involve dysfunctional endothelial cells (ECs), dysregulated immunity and inflammation in the lung. We hypothesize that a developmental process called endothelial to haematopoietic transition (EHT) contributes to the pathogenesis of pulmonary hypertension (PH). We sought to determine the role of EHT in mouse models of PH, to characterize specific cell types involved in this process, and to identify potential therapeutic targets to prevent disease progression. Methods and results:When transgenic mice with fluorescence protein ZsGreen-labelled ECs were treated with Sugen/hypoxia (Su/Hx) combination to induce PH, the percentage of ZsGreen+ haematopoietic cells in the peripheral blood, primarily of myeloid lineage, significantly increased. This occurrence coincided with the depletion of bone marrow (BM) ZsGreen+ c-kit+ CD45- endothelial progenitor cells (EPCs), which could be detected accumulating in the lung upon PH-induction. Quantitative RT-PCR based gene array analysis showed that key transcription factors driving haematopoiesis were expressed in these EPCs. When transplanted into lethally irradiated recipient mice, the BM-derived EPCs exhibited long-term engraftment and haematopoietic differentiation capability, indicating these EPCs are haemogenic in nature. Specific inhibition of the critical haematopoietic transcription factor Runx1 blocked the EHT process in vivo, prevented egress of the BM EPCs and ultimately attenuated PH progression in Su/Hx- as well as in monocrotaline-induced PH in mice. Thus, myeloid-skewed EHT promotes the development of PH and inhibition of this process prevents disease progression in mouse models of PH. Furthermore, high levels of Runx1 expression were found in circulating CD34+ CD133+ EPCs isolated from peripheral blood of patients with PH, supporting the clinical relevance of our proposed mechanism of EHT. Conclusion:EHT contributes to the pathogenesis of PAH. The transcription factor Runx1 may be a novel therapeutic target for the treatment of PAH.

Project description:Bronchopulmonary dysplasia (BPD), a chronic lung disease in premature infants, results from mechanical ventilation and hyperoxia, amongst other factors. Although most BPD survivors can be weaned from supplemental oxygen, many show evidence of cardiovascular sequelae in adulthood, including pulmonary hypertension and pulmonary vascular remodeling. Endothelial-mesenchymal transition (EndoMT) plays an important role in mediating vascular remodeling in idiopathic pulmonary arterial hypertension. Whether hyperoxic exposure, a known mediator of BPD in rodent models, causes EndoMT resulting in vascular remodeling and pulmonary hypertension remains unclear. We hypothesized that neonatal hyperoxic exposure causes EndoMT, leading to the development of pulmonary hypertension in adulthood. To test this hypothesis, newborn mice were exposed to hyperoxia and then allowed to recover in room air until adulthood. Neonatal hyperoxic exposure gradually caused pulmonary vascular and right ventricle remodeling as well as pulmonary hypertension. Male mice were more susceptible to developing pulmonary hypertension compared to female mice, when exposed to hyperoxia as newborns. Hyperoxic exposure induced EndoMT in mouse lungs as well as in cultured lung microvascular endothelial cells (LMVECs) isolated from neonatal mice and human fetal donors. This was augmented in cultured LMVECs from male donors compared to those from female donors. Using primary mouse LMVECs, hyperoxic exposure increased phosphorylation of both Smad2 and Smad3, but reduced Smad7 protein levels. Treatment with a selective TGF-β inhibitor SB431542 blocked hyperoxia-induced EndoMT in vitro. Altogether, we show that neonatal hyperoxic exposure caused vascular remodeling and pulmonary hypertension in adulthood. This was associated with increased EndoMT. These novel observations provide mechanisms underlying hyperoxia-induced vascular remodeling and potential approaches to prevent BPD-associated pulmonary hypertension by targeting EndoMT. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Project description:Pulmonary vascular remodeling characterized by concentric wall thickening and intraluminal obliteration is a major contributor to the elevated pulmonary vascular resistance in patients with idiopathic pulmonary arterial hypertension (IPAH). Here we report that increased hypoxia-inducible factor 2? (HIF-2?) in lung vascular endothelial cells (LVECs) under normoxic conditions is involved in the development of pulmonary hypertension (PH) by inducing endothelial-to-mesenchymal transition (EndMT), which subsequently results in vascular remodeling and occlusive lesions. We observed significant EndMT and markedly increased expression of SNAI, an inducer of EndMT, in LVECs from patients with IPAH and animals with experimental PH compared with normal controls. LVECs isolated from IPAH patients had a higher level of HIF-2? than that from normal subjects, whereas HIF-1? was upregulated in pulmonary arterial smooth muscle cells (PASMCs) from IPAH patients. The increased HIF-2? level, due to downregulated prolyl hydroxylase domain protein 2 (PHD2), a prolyl hydroxylase that promotes HIF-2? degradation, was involved in enhanced EndMT and upregulated SNAI1/2 in LVECs from patients with IPAH. Moreover, knockdown of HIF-2? (but not HIF-1?) with siRNA decreases both SNAI1 and SNAI2 expression in IPAH-LVECs. Mice with endothelial cell (EC)-specific knockout (KO) of the PHD2 gene, egln1 (egln1EC-/-), developed severe PH under normoxic conditions, whereas Snai1/2 and EndMT were increased in LVECs of egln1EC-/- mice. EC-specific KO of the HIF-2? gene, hif2a, prevented mice from developing hypoxia-induced PH, whereas EC-specific deletion of the HIF-1? gene, hif1a, or smooth muscle cell (SMC)-specific deletion of hif2a, negligibly affected the development of PH. Also, exposure to hypoxia for 48-72 h increased protein level of HIF-1? in normal human PASMCs and HIF-2? in normal human LVECs. These data indicate that increased HIF-2? in LVECs plays a pathogenic role in the development of severe PH by upregulating SNAI1/2, inducing EndMT, and causing obliterative pulmonary vascular lesions and vascular remodeling.

Dataset Information

Galectin-3 Mediates Endothelial-to-Mesenchymal Transition in Pulmonary Arterial Hypertension.

Publications

Galectin-3 Mediates Endothelial-to-Mesenchymal Transition in Pulmonary Arterial Hypertension.

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