Response time of an electron inside a molecule to light in strong-field ionization.

We study ionization of aligned H2+ in strong elliptically polarized laser fields numerically and analytically. The calculated offset angle in photoelectron momentum distribution is several degrees larger for the molecule than a model atom with similar ionization potential at diverse laser parameters. Using a strong-field model that considers the properties of multi-center and single-center Coulomb potentials, we are able to quantitatively reproduce this angle difference between the molecule and the atom. Further analyses based on this model show that the response time of electron to light which is encoded in the offset angle and is manifested as the time spent in tunneling ionization, is about 15 attoseconds longer for the molecule than the atom. This time difference is further enlarged when increasing the internuclear distance of the molecule.

Four New Species of Russula Subsection Sardoninae from China.

Four new species of Russula subsection Sardoninae from northern and southwestern China under coniferous and deciduous trees are proposed as R. begonia, R. photinia, R. rhodochroa, and R. rufa. Illustrations and descriptions of R. gracillima, R. leucomarginata, R. roseola, and the above four new species are provided based on evidence of morphological characters and phylogenetic analyses of the internal transcribed spacer (ITS), as well as the multi-locus of mtSSU, nLSU, rpb1, rpb2 and tef1-α. The relationships between these new species and allied taxa are discussed.

Wnt5a/Ror2 promotes vascular smooth muscle cells proliferation via activating PKC.

INTRODUCTION: Abnormal proliferation of vascular smooth muscle cells (VSMCs) can cause various vascular diseases, such as atherosclerosis, restenosis, and pulmonary hypertension. However, the effect and underlying mechanism of Wnt5a on the proliferation of VSMCs remain unclear. Our study aimed to investigate whether Wnt5a/Ror2 promotes vascular smooth muscle cell proliferation via activating protein kinase C (PKC), thereby effectively alleviating vascular proliferative diseases. MATERIAL AND METHODS: The proliferation of HA-VSMC cell line was evaluated by CCK-8, EdU, and Plate clone formation assays. The Wnt5a gene knockdown and overexpression were carried out by standard methods. The interaction between Wnt5a and Ror2 was explored by co-immunoprecipitation. Western blotting and immunofluorescence were used to determine the expression levels of key proteins in VSMCs. RESULTS: The present study found that the expression of Wnt5a protein increased significantly in the proliferation of VSMCs stimulated by 10% serum in a time-dependent manner. Furthermore, the proliferative rate of VSMCs overexpressing Wnt5a was dramatically accelerated, whereas Wnt5a knockdown using siWnt5a reversed thisproliferative effect. Wnt5a up-regulated the expression of receptor tyrosine kinase-like orphan receptor 2 (Ror2) by binding to it. Further studies indicated that Wnt5a induces the PKC expression in VSMCs and knockdown of Wnt5a or Ror2 could inhibit PKC phosphorylation. CONCLUSIONS: Wnt5a could effectively promote the proliferation of VSMCs, which might be related to the binding of Wnt5a and Ror2 to activate PKC.

Three new Russula species in sect. Ingratae (Russulales, Basidiomycota) from southern China.

Three new species of Russulasection Ingratae, found in Guizhou and Jiangsu Provinces, southern China, are proposed: R.straminella, R.subpectinatoides and R.succinea. Photographs, line drawings and detailed morphological descriptions for these species are provided with comparisons against closely-related taxa. Phylogenetic analysis of the internal transcribed spacer (ITS) region supported the recognition of these specimens as new species. Additionally, R.indocatillus is reported for the first time from China and morphological and phylogenetic data are provided for the Chinese specimens.

Direct Interaction of Daxx and Androgen Receptor Is Required for Their Regulatory Activity in Cholesterol Biosynthesis.

INTRODUCTION: Homeostasis of cholesterol is crucial for cellular function, and dysregulated cholesterol biosynthesis is a metabolic event that can lead to hepatic and cardiovascular abnormalities. OBJECTIVE: The aim of this study was to investigate the effects and mechanisms of domain-associated protein (Daxx) and androgen receptor (AR) on intracellular cholesterol synthesis. METHODS: HepG2 cells were transfected with pCDNA3.1(+)/Daxx plasmid or treated with testosterone propionate to observe the effects of Daxx and AR on intracellular cholesterol levels. Co-immunoprecipitation experiments were performed to identify the interaction between Daxx and AR and to explore the regulatory effects of this interaction on cholesterol synthesis. RESULTS: Our experiments showed that AR promoted cholesterol synthesis and accumulation by activating sterol-regulatory element-binding protein isoform 2. AR-induced cholesterol synthesis was inhibited by Daxx; however, the expression of AR was not affected. Further studies demonstrated the existence of direct binding between Daxx and AR and this interaction was required to suppress AR activity. CONCLUSIONS: The Daxx-mediated antagonism of AR depicts a more complete picture as to how Daxx regulates intracellular cholesterol level and provides a new target for treatment of atherosclerosis.

Acid-Sensing Ion Channel 1/Calpain1 Activation Impedes Macrophage ATP-Binding Cassette Protein A1-Mediated Cholesterol Efflux Induced by Extracellular Acidification.

BACKGROUND: Extracellular acidification is a common feature of atherosclerotic lesions, and such an acidic microenvironment impedes ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux and promotes atherogenesis. However, the underlying mechanism is still unclear. Acid-sensing ion channel 1 (ASIC1) is a critical H+ receptor, which is responsible for the perception and transduction of extracellular acidification signals. AIM: In this study, we explored whether or how ASIC1 influences extracellular acidification-induced ABCA1-mediated cholesterol efflux from macrophage-derived foam cells. METHODS: RAW 264.7 macrophages were cultured in an acidic medium (pH 6.5) to generate foam cells. Then the intracellular lipid deposition, cholesterol efflux, and ASIC1/calpain1/ABCA1 expressions were evaluated. RESULTS: We showed that extracellular acidification enhanced ASIC1 expression and translocation, promoted calpain1 expression and lipid accumulation, and decreased ABCA1 protein expression as well as ABCA1-mediated cholesterol efflux. Of note, inhibiting ASIC1 activation with amiloride or Psalmotoxin 1 (PcTx-1) not only lowered calpain1 protein level and lipid accumulation but also enhanced ABCA1 protein levels and ABCA1-mediated cholesterol efflux of macrophages under extracellular acidification conditions. Furthermore, similar results were observed in macrophages treated with calpain1 inhibitor PD150606. CONCLUSION: Extracellular acidification declines cholesterol efflux via activating ASIC1 to promote calpain1-mediated ABCA1 degradation. Thus, ASIC1 may be a novel therapeutic target for atherosclerosis.

Coulomb-induced ionization time lag after electrons tunnel out of a barrier.

After electrons tunnel out of a laser-Coulomb-formed barrier, the movement of the tunneling electron can be affected by the Coulomb potential. We show that this Coulomb effect induces a large time difference (longer than a hundred attoseconds) between the tunneling-out time at which the electron exits the barrier and the ionization time at which the electron is free. This large time difference has important influences on strong-field processes such as above-threshold ionization and high-harmonic generation, with remarkably changing time-frequency properties of electron trajectories. Some semi-quantitative evaluations on these influences are addressed, which provide new insight into strong-field processes and give suggestions on attosecond measurements.

The crosstalk: exosomes and lipid metabolism.

Exosomes have been considered as novel and potent vehicles of intercellular communication, instead of "cell dust". Exosomes are consistent with anucleate cells, and organelles with lipid bilayer consisting of the proteins and abundant lipid, enhancing their "rigidity" and "flexibility". Neighboring cells or distant cells are capable of exchanging genetic or metabolic information via exosomes binding to recipient cell and releasing bioactive molecules, such as lipids, proteins, and nucleic acids. Of note, exosomes exert the remarkable effects on lipid metabolism, including the synthesis, transportation and degradation of the lipid. The disorder of lipid metabolism mediated by exosomes leads to the occurrence and progression of diseases, such as atherosclerosis, cancer, non-alcoholic fatty liver disease (NAFLD), obesity and Alzheimer's diseases and so on. More importantly, lipid metabolism can also affect the production and secretion of exosomes, as well as interactions with the recipient cells. Therefore, exosomes may be applied as effective targets for diagnosis and treatment of diseases. Video abstract.

Mechanisms of Berberine for the Treatment of Atherosclerosis Based on Network Pharmacology.

Atherosclerosis is a common metabolic disease characterized by lipid metabolic disorder. The processes of atherosclerosis include endothelial dysfunction, new endothelial layer formation, lipid sediment, foam cell formation, plaque formation, and plaque burst. Owing to the adverse effects of first-line medications, it is urgent to discover new medications to deal with atherosclerosis. Berberine is one of the most promising natural products derived from traditional Chinese medicine. However, the panoramic mechanism of berberine against atherosclerosis has not been discovered clearly. In this study, we used network pharmacology to investigate the interaction between berberine and atherosclerosis. We identified potential targets related to berberine and atherosclerosis from several databases. A total of 31 and 331 putative targets for berberine and atherosclerosis were identified, respectively. Then, we constructed berberine and atherosclerosis targets with PPI data. Berberine targets network with PPI data had 3204 nodes and 79437 edges. Atherosclerosis targets network with PPI data had 5451 nodes and 130891 edges. Furthermore, we merged the two PPI networks and obtained the core PPI network from the merged PPI network. The core PPI network had 132 nodes and 3339 edges. At last, we performed functional enrichment analyses including GO and KEGG pathway analysis in David database. GO analysis indicated that the biological processes were correlated with G1/S transition of mitotic cells cycle. KEGG pathway analysis found that the pathways directly associated with berberine against atherosclerosis were cell cycle, ubiquitin mediated proteolysis, MAPK signaling pathway, and PI3K-Akt signaling pathway. After combining the results in context with the available treatments for atherosclerosis, we considered that berberine inhibited inflammation and cell proliferation in the treatment of atherosclerosis. Our study provided a valid theoretical foundation for future research.

Autophagy in chronic stress induced atherosclerosis.

Atherosclerosis, a complex multifactorial disease, is the leading cause of acute cardiovascular events. Substantial evidence confirms that chronic stress plays a pivot role in the occurrence and development of atherosclerosis, but the specific mechanism remains unclear. Autophagy serves as a safeguard mechanism for sustaining cellular homeostasis via eliminating unnecessary or/and harmful components, and damaged organelles in response to various stress. An increasing number of studies indicate that autophagy plays vital roles in the development of atherosclerosis. Therefore, understanding the role of chronic stress in the regulation of autophagy may provide new insight into prevention and treatment atherosclerotic disease, especially with respect to emerging targeted therapy. In present review, we focus on changes in autophagic function under chronic stress and its relationship to atherosclerosis.

Acid-sensing ion channels: Linking extracellular acidification with atherosclerosis.

Extracellular acidification in atherosclerosis-prone regions of arterial walls is considered pro-atherosclerotic by exerting detrimental effect on macrophages, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Acid-sensing ion channels (ASICs), a family of extracellular H+ (proton)-gated cation channels, are present extensively in the nervous system and other tissues, implying physiologic as well as pathophysiologic importance. Aberrant activation of ASICs is thought to be associated in EC dysfunction, macrophage phenotypic switch, and VSMC migration and proliferation. Although in vitro evidence acknowledges the contribution of ASIC activation in atherosclerosis, no direct evidence confirms their pro-atherosclerotic roles in vivo. In this review, the effect of extracellular acidity on three major contributors, ECs, macrophages, and VSMCs, is discussed focusing on the potential roles of ASICs in atherosclerotic development and underlying pathology. A more comprehensive understanding of ASICs in these processes may provide promising new therapeutic targets for treatment and prevention of atherosclerotic diseases.

Autophagy: a killer or guardian of vascular smooth muscle cells.

Vascular smooth muscle cells (VSMCs) is one of the main intracellular components of the blood vessel wall. The abnormalities of VSMCs participate in the development of cardiovascular diseases such as atherosclerosis, hypertension, and restenosis, especially the formation and stability of atherosclerotic plaques. Autophagy is involved in the regulation of proliferation, migration and phenotype switching of VSMCs, which in turn affects the pathological process of atherosclerosis. However, the autophagy of VSMCs has a dual effect on cells survival. Autophagy is induced in VSMCs by various stimuli such as 7-ketocholesterol (7-KC), unsaturated lipid peroxidation-derived aldehyde and excess free cholesterol, thereby promoting VSMCs survival and stabilising atherosclerotic plaque. Conversely, autophagy caused by factors such as osteopontin (OPN), angiotensin II (Ang II) and nicotine can accelerate the death of VSMCs, further accelerating atherosclerotic lesions. In addition, mitophagy and lipophagy as selective autophagy are also involved in the outcome of VSMCs as well as progression of atherosclerotic lesion. Currently, there are only a few drugs available to induce VSMCs autophagy, such as atorvastatin, telmisartan and so on. Due to the important role of VSMCs autophagy in the progression of atherosclerosis plaques, drugs that directly target autophagy of VSMCs are urgently needed to be developed.

[Daxx overexpression inhibits Angâ ¡-induced proliferation and migration in vascular smooth muscle cells].

OBJECTIVE: To construct a recombinant lentiviral expression vector pCDH-Daxx-EGFP to investigate the effect of Daxx on the proliferation of vascular smooth muscle cells (VSMCs). METHODS: The recombinant lentiviral expression vector pCDHDaxx-EGFP was constructed using PCR-based accurate synthesis method. After identification by sequencing and enzyme digestion, the recombinant lentiviral vector was contransfected into 293T cells with lentivirus packaging vector. The recombinant lentivirus particles were collected and purified to infect VSMCs, whose expression of Daxx was detected with Western boltting. The cells infected with the empty vector pCDH-EGFP or pCDH-Daxx-EGFP were incubated in serum-free medium or in the presence of angiotensin Ⅱ (AngⅡ). The cell viability was determined with MTT assay, and the cell cycle changes were analyzed with flow cytometry. The cell migration ability was assessed using a scratch wound healing assay. The expression of p-Akt protein in the cells was detected using Western blotting. RESULTS: Double enzyme digestion and sequencing confirmed successful construction of the recombinant plasmid. Compared with the cells infected with the empty vector, the cells infected with pCDH-Daxx-EGFP exhibited significantly increased expressions of Daxx protein (P < 0.05). AngⅡ treatment of the cells infected with the pCDH-Daxx-EGFP, as compared with the cells infected with the empty vector, significantly lowered the cell viability, S phase cell ratio and cell migration ability (P < 0.05), and significantly decreased the expression level of p-Akt protein (P < 0.05). CONCLUSIONS: We successfully constructed the recombinant lentiviral vector pCDH-Daxx-EGFP and overexpressed Daxx in primary cultured VSMCs using this vector. Daxx overexpression can inhibit AngⅡ-induced proliferation and migration in VSMCs probably by regulating p-Akt protein.

miR-142-3p Regulates Milk Synthesis and Structure of Murine Mammary Glands via PRLR-Mediated Multiple Signaling Pathways.

Murine mammary gland is an ideal model for studying the development and milk synthesis in dairy animals. MicroRNAs play an important role in milk synthesis and mammary gland development; however, the molecular mechanism of miR-142-3p continues to be poorly understood. Here, we knocked down miR-142-3p expression in vitro and vivo, increased the prolactin receptor expression and activated many downstream cellular proteins, such as mammalian target of rapamycin, sterol regulatory element-binding transcription factor 1, cyclin D1, and signal transducer and activator of transcription 5. Additionally, miR-142-3p knockdown in mouse mammary gland epithelial cells increased proliferation but not viability, induced cell cycle progression, decreased apoptosis, and increased the expression of triglycerides and ß-casein. Moreover, miR-142-3p knockdown in murine mammary gland tissue in vivo affected the structure and function of the mammary gland, which showed an increased number of lobules and ducts and was more capable of producing milk. However, overexpression of miR-142-3p had the opposite effects. In summary, these data reveal that miR-142-3p regulates milk synthesis and the structure of murine mammary glands via PRLR-mediated multiple signaling pathways.

Astragaloside VI Promotes Neural Stem Cell Proliferation and Enhances Neurological Function Recovery in Transient Cerebral Ischemic Injury via Activating EGFR/MAPK Signaling Cascades.

Radix Astragali (AR) is a commonly used medicinal herb for post-stroke disability in Traditional Chinese Medicine but its active compounds for promoting neurogenic effects are largely unknown. In the present study, we tested the hypothesis that Astragaloside VI could be a promising active compound from AR for adult neurogenesis and brain repair via targeting epidermal growth factor (EGF)-mediated MAPK signaling pathway in post-stroke treatment. By using cultured neural stem cells (NSCs) and experimental stroke rat model, we investigated the effects of Astragaloside VI on inducing NSCs proliferation and self-renewal in vitro, and enhancing neurogenesis for the recovery of the neurological functions in post-ischemic brains in vivo. For animal experiments, rats were undergone 1.5 h middle cerebral artery occlusion (MCAO) plus 7 days reperfusion. Astragaloside VI (2 µg/kg) was daily administrated by intravenous injection (i.v.) for 7 days. Astragaloside VI treatment promoted neurogenesis and astrogenic formation in dentate gyrus zone, subventricular zone, and cortex of the transient ischemic rat brains in vivo. Astragaloside VI treatment enhanced NSCs self-renewal and proliferation in the cultured NSCs in vitro without affecting NSCs differentiation. Western blot analysis showed that Astragaloside VI up-regulated the expression of nestin, p-EGFR and p-MAPK, and increased neurosphere sizes, whose effects were abolished by the co-treatment of EGF receptor inhibitor gefitinib and ERK inhibitor PD98059. Behavior tests revealed that Astragaloside VI promoted the spatial learning and memory and improved the impaired motor function in transient cerebral ischemic rats. Taken together, Astragaloside VI could effectively activate EGFR/MAPK signaling cascades, promote NSCs proliferation and neurogenesis in transient cerebral ischemic brains, and improve the repair of neurological functions in post-ischemic stroke rats. Astragaloside VI could be a new therapeutic drug candidate for post-stroke treatment.

Routes of odd-even harmonic emission from oriented polar molecules.

We study odd-even high-harmonic generation (HHG) from oriented asymmetric molecules with different symmetries in strong laser fields. A model based on strong-field approximations is used which allows us to resolve the contributions of different emission routes to odd-even HHG. The comparison between the HHG yields of all routes versus one certain route demonstrates that the routes in which the electron ionizes from the gerade component of the asymmetric orbital contribute mainly to odd-even HHG. We show that the potential mechanism is associated with effects of intramolecular interference in tunneling ionization as the bound electron passes through the barrier formed by the laser field and the asymmetric Coulomb potential. The influences of different emission routes on asymmetric orbital imagining with odd-even HHG are also addressed.

Ablation of endothelial prolyl hydroxylase domain protein-2 promotes renal vascular remodelling and fibrosis in mice.

Accumulating evidence demonstrates that hypoxia-inducible factor (HIF-α) hydroxylase system has a critical role in vascular remodelling. Using an endothelial-specific prolyl hydroxylase domain protein-2 (PHD2) knockout (PHD2EC KO) mouse model, this study investigates the regulatory role of endothelial HIF-α hydroxylase system in the development of renal fibrosis. Knockout of PHD2 in EC up-regulated the expression of HIF-1α and HIF-2α, resulting in a significant decline of renal function as evidenced by elevated levels of serum creatinine. Deletion of PHD2 increased the expression of Notch3 and transforming growth factor (TGF-ß1) in EC, thus further causing glomerular arteriolar remodelling with an increased pericyte and pericyte coverage. This was accompanied by a significant elevation of renal resistive index (RI). Moreover, knockout of PHD2 in EC up-regulated the expression of fibroblast-specific protein-1 (FSP-1) and increased interstitial fibrosis in the kidney. These alterations were strongly associated with up-regulation of Notch3 and TGF-ß1. We concluded that the expression of PHD2 in endothelial cells plays a critical role in renal fibrosis and vascular remodelling in adult mice. Furthermore, these changes were strongly associated with up-regulation of Notch3/TGF-ß1 signalling and excessive pericyte coverage.

Oxidized low-density lipoprotein induced mouse hippocampal HT-22 cell damage via promoting the shift from autophagy to apoptosis.

AIMS: Although oxidized low-density lipoprotein (ox-LDL) in the brain induces neuronal death, the mechanism underlying the damage effects remains largely unknown. Given that the ultimate outcome of a cell is depended on the balance between autophagy and apoptosis, this study was performed to explore whether ox-LDL induced HT-22 neuronal cell damage via autophagy impairment and apoptosis enhancement. METHODS: Flow cytometry and transmission electron microscopy (TEM) were used to evaluate changes in cell apoptosis and autophagy, respectively. The protein expression of LC3-II, p62, Bcl-2, and Bax in HT-22 cells was measured by Western bolt analysis. RESULTS: Our study confirmed that 100 µg/mL of ox-LDL not only promoted TH-22 cell apoptosis, characterized by elevated cell apoptosis rate and Bax protein expression, decreased Bcl-2 protein expression, and damaged cellular ultrastructures, but also impaired autophagy as indicated by the decreased LC3-II levels and the increased p62 levels. Importantly, all of these effects of ox-LDL were significantly aggravated by cotreatment with chloroquine (an inhibitor of autophagy flux). In contrast, cotreatment with rapamycin (an inducer of autophagy) remarkably reversed these effects of ox-LDL. CONCLUSIONS: Taken together, our results indicated that ox-LDL-induced shift from autophagy to apoptosis contributes to HT-22 cell damage.

Notch3 deficiency impairs coronary microvascular maturation and reduces cardiac recovery after myocardial ischemia.

RATIONALE: Vascular maturation plays an important role in wound repair post-myocardial infarction (MI). The Notch3 is critical for pericyte recruitment and vascular maturation during embryonic development. OBJECTIVE: This study is to test whether Notch3 deficiency impairs vascular maturation and blunts cardiac functional recovery post-MI. APPROACH AND RESULTS: Wild type (WT) and Notch3 knockout (Notch3KO) mice were subjected to MI by the ligation of left anterior descending coronary artery (LAD). Cardiac function and coronary blood flow reserve (CFR) were measured by echocardiography. The expression of angiogenic growth factor, pericyte/capillary coverage and arteriolar formation were analyzed. Loss of Notch3 in mice resulted in a significant reduction of pericytes and small arterioles. Notch3 KO mice had impaired pericyte/capillary coverage and CFR compared to WT mice. Notch3 KO mice were more prone to ischemic injury with larger infarcted size and higher rates of mortality. The expression of CXCR-4 and VEGF/Ang-1 was significantly decreased in Notch3 KO mice. Notch3 KO mice also had few NG2+/Sca1+ and NG2+/c-kit+ progenitor cells in the ischemic area and exhibited worse cardiac function recovery at 2weeks after MI. These were accompanied by a significant reduction of pericyte/capillary coverage and arteriolar maturation. Furthermore, Notch3 KO mice subjected to MI had increased intracellular adhesion molecule-2 (ICAM-2) expression and CD11b+ macrophage infiltration into ischemic areas compared to that of WT mice. CONCLUSION: Notch3 mutation impairs recovery of cardiac function post-MI by the mechanisms involving the pre-existing coronary microvascular dysfunction conditions, and impairment of pericyte/progenitor cell recruitment and microvascular maturation.

Loss of prolyl hydroxylase domain protein 2 in vascular endothelium increases pericyte coverage and promotes pulmonary arterial remodeling.

Pulmonary arterial hypertension (PAH) is a leading cause of heart failure. Although pulmonary endothelial dysfunction plays a crucial role in the progression of the PAH, the underlying mechanisms are poorly understood. The HIF-α hydroxylase system is a key player in the regulation of vascular remodeling. Knockout of HIF-2α has been reported to cause pulmonary hypertension. The present study examined the role of endothelial cell specific prolyl hydroxylase-2 (PHD2) in the development of PAH and pulmonary vascular remodeling. The PHD2f/f mouse was crossbred with VE-Cadherin-Cre promoter mouse to generate an endothelial specific PHD2 knockout (Cdh5-Cre-PHD2ECKO) mouse. Pulmonary arterial pressure and the size of the right ventricle was significantly elevated in the PHD2ECKO mice relative to the PHD2f/f controls. Knockout of PHD2 in EC was associated with vascular remodeling, as evidenced by an increase in pulmonary arterial media to lumen ratio and number of muscularized arterioles. The pericyte coverage and vascular smooth muscle cells were also significantly increased in the PA. The increase in vascular pericytes was associated with elevated expression of fibroblast specific protein-1 (FSP-1). Moreover, perivascular interstitial fibrosis of pulmonary arteries was significantly increased in the PHD2ECKO mice. Mechanistically, knockout of PHD2 in EC increased the expression of Notch3 and transforming growth factor (TGF-ß) in the lung tissue. We conclude that the expression of PHD2 in endothelial cells plays a critical role in preventing pulmonary arterial remodeling in mice. Increased Notch3/TGF-ß signaling and excessive pericyte coverage may be contributing to the development of PAH following deletion of endothelial PHD2.