Sox17 Deficiency Promotes Pulmonary Arterial Hypertension via HGF/c-Met Signaling.

BACKGROUND: In large-scale genomic studies, Sox17, an endothelial-specific transcription factor, has been suggested as a putative causal gene of pulmonary arterial hypertension (PAH); however, its role and molecular mechanisms remain to be elucidated. We investigated the functional impacts and acting mechanisms of impaired Sox17 (SRY-related HMG-box17) pathway in PAH and explored its potential as a therapeutic target. METHODS: In adult mice, Sox17 deletion in pulmonary endothelial cells (ECs) induced PAH under hypoxia with high penetrance and severity, but not under normoxia. RESULTS: Key features of PAH, such as hypermuscularization, EC hyperplasia, and inflammation in lung arterioles, right ventricular hypertrophy, and elevated pulmonary arterial pressure, persisted even after long rest in normoxia. Mechanistically, transcriptomic profiling predicted that the combination of Sox17 deficiency and hypoxia activated c-Met signaling in lung ECs. HGF (hepatocyte grow factor), a ligand of c-Met, was upregulated in Sox17-deficient lung ECs. Pharmacologic inhibition of HGF/c-Met signaling attenuated and reversed the features of PAH in both preventive and therapeutic settings. Similar to findings in animal models, Sox17 levels in lung ECs were repressed in 26.7% of PAH patients (4 of 15), while those were robust in all 14 non-PAH controls. HGF levels in pulmonary arterioles were increased in 86.7% of patients with PAH (13 of 15), but none of the controls showed that pattern. CONCLUSIONS: The downregulation of Sox17 levels in pulmonary arterioles increases the susceptibility to PAH, particularly when exposed to hypoxia. Our findings suggest the reactive upregulation of HGF/c-Met signaling as a novel druggable target for PAH treatment.

Sulfur and methane oxidation by a single microorganism.

Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from wetlands are mitigated by methanotrophic bacteria at the oxic-anoxic interface, a zone of intense redox cycling of carbon, sulfur, and nitrogen compounds. Here, we report on the isolation of an aerobic methanotrophic bacterium, 'Methylovirgula thiovorans' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, strain HY1 is the first bacterium shown to aerobically oxidize both methane and reduced sulfur compounds for growth. Genomic and proteomic analyses showed that soluble methane monooxygenase and XoxF-type alcohol dehydrogenases are responsible for methane and methanol oxidation, respectively. Various pathways for respiratory sulfur oxidation were present, including the Sox-rDsr pathway and the S4I system. Strain HY1 employed the Calvin-Benson-Bassham cycle for CO2 fixation during chemolithoautotrophic growth on reduced sulfur compounds. Proteomic and microrespirometry analyses showed that the metabolic pathways for methane and thiosulfate oxidation were induced in the presence of the respective substrates. Methane and thiosulfate could therefore be independently or simultaneously oxidized. The discovery of this versatile bacterium demonstrates that methanotrophy and thiotrophy are compatible in a single microorganism and underpins the intimate interactions of methane and sulfur cycles in oxic-anoxic interface environments.

Multimodal evaluation of an interphotoreceptor retinoid-binding protein-induced mouse model of experimental autoimmune uveitis.

We aimed to characterize the vascular phenotypes of an experimental autoimmune retinal uveitis (EAU) model induced by interphotoreceptor retinoid-binding protein (IRBP) using multimodal imaging techniques. We systemically administered IRBP or vehicle to adult C57BL/6 mice. Fundus photography, optical coherence tomography (OCT), in vivo live confocal imaging using different tracers, OCT angiography (OCTA), and electroretinography (ERG) were performed after IRBP immunization. Hematoxylin and eosin and immunofluorescence staining were performed to characterize the immune response and vascular permeability. Mice with EAU exhibited perivascular inflammation, vitritis, and superficial retinal inflammation on fundus photography and OCT. H&E revealed immune cell infiltration in the perivascular area of the retina and choroid accompanied by a significant degree of perivasculitis that subsequently damaged photoreceptors 3 weeks postimmunization. Immunofluorescence staining showed subsequent transcytosis induction after local microglial activation followed by neutrophil recruitment in the perivascular area. Transcytosis in the superficial and deep vascular areas was improved by immune cell suppression. Intravital in vivo confocal imaging showed signs of neutrophil infiltration and obstructive vasculitis with perivascular leakage 3 weeks postimmunization. OCTA revealed a significant decrease in vascular flow in the deep capillary layer of the retina. Functional analysis showed that scotopic responses were intact at 2 weeks; however, normal photopic and scotopic responses were hardly detected in mice with EAU mice at 3 weeks postimmunization. Our data suggest that inflammatory cell activation and subsequent transcytosis induction in endothelial cells might be a major pathogenic factor for vascular leakage in uveitis, providing new insights into the pathophysiology of retinal vasculitis in noninfectious uveitis.

Predictors of In-Hospital Mortality in Korean Patients with Acute Myocardial Infarction.

Acute myocardial infarction (AMI) is a fatal cardiovascular disease, and mortality is relatively high; therefore, integrated assessment is necessary for its management. There are several risk predictive models, but treatment trends have changed due to newly introduced medications and the universal use of percutaneous coronary intervention (PCI). The author aimed to find out predictive factors of in-hospital mortality in Korean patients with AMI. A group of 13,104 patients with AMI enrolled in the Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH) registry were divided into two groups. One was a derivation group for evaluating mortality prediction; the other was a validation group for the application of risk prediction. In-hospital mortality was 4.2% (n=552). With hierarchical and stepwise multivariate analyses, nine factors were shown to predict in-hospital mortality for Korean patients with AMI. These were 1) being over 65 years of age, 2) high Killip class over II, 3) hyperglycemia over 180 mg/dl, 4) tachycardia over 100/min, 5) serum creatinine over 1.5 mg/dl, 6) atypical chest pain, 7) low systolic blood pressure under 90 mmHg, 8) low Thrombolysis In Myocardial Infarction (TIMI) flow (TIMI 0-II) before PCI and 9) low TIMI flow (TIMI 0-II) after PCI. The validation group showed a predictive power of 88.3%. Old age, high Killip class, hyperglycemia, tachycardia, renal dysfunction, atypical chest pain, low systolic blood pressure, and low TIMI flow are important risk factors of in-hospital mortality in Korean patients with AMI.

Factors affecting use of word-of-mouth by dental patients.

OBJECTIVES: Word-of-mouth (WOM) refers to communication among consumers, which greatly influences the marketing strategies of dental clinics. This study aimed to explore factors that affect use of WOM by dental patients and to analyse their pathways. METHODS: The participants were 520 outpatients from four private dental clinics. Data were obtained from a survey using self-reported questionnaires, which included questions regarding seven latent variables: five exogenous variables, including medical service quality (physical environment, customer service, patient relationship quality) and individual characteristic variables (opinion leader tendency, social hub tendency); and two endogenous variables (intention to recommend, WOM experience). Statistical analysis was performed using structural equation modelling. RESULTS: Significant associations were found in the pathways between relationship quality and intention to recommend, intention to recommend and WOM, and opinion leader tendency and WOM (P < 0.001). Higher patient relationship quality and higher intention to recommend were related to positive WOM, as was higher opinion leader tendency. CONCLUSIONS: Improving patient relationship quality can promote positive WOM for dental clinics. Strategies are needed to promote a positive perception of dental clinics by effectively responding to the views of patients with strong opinion leader tendencies.

A novel polymer-free drug-eluting stent coated with everolimus using nitrogen-doped titanium dioxide film deposition in a porcine coronary restenosis model.

BACKGROUND: Titanium dioxide (TiO2) films have superior biocompatibility and may be effective as drug-binding matrices for drug-eluting stents (DESs). We sought to evaluate efficacy of a polymer-free DES coated with everolimus using nitrogen-doped TiO2 film deposition in a porcine coronary restenosis model. METHODS: Forty coronary arteries in 20 pigs were randomly allocated to group 1 (bare-metal stents (BMSs), 3.0×18mm, n=10), group 2 (BMSs with nitrogen-doped TiO2 film deposition, 3.0×18mm, n=10), group 3 [commercial everolimus-eluting stent, 3.0×18mm, n=10], and group 4 (polymer-free everolimus-eluting stent using nitrogen-doped TiO2 film deposition, 3.0×18mm, n=10). Stents were randomly implanted in the left anterior descending coronary artery and left circumflex artery with stent:artery ratio of 1.3. Four weeks later, pigs underwent follow-up coronary angiography and were sacrificed for histopathologic analysis. RESULTS: Percent area stenosis was greater in group 1 compared to groups 3 and 4 (46.4±13.8% vs. 30.2±11.7% vs. 29.2±8.9%, respectively, p=0.005). Fibrin score was lower in groups 1 and 2, compared to groups 3 and 4: 0.87±0.67 vs. 0.76±0.61 vs. 2.27±0.24 vs. 1.75±0.31, respectively, p<0.001). Injury score and inflammation score were not different. Comparison between DES showed a higher fibrin score in group 3 than group 4 (2.27±0.24 vs. 1.75±0.31, p=0.023). CONCLUSIONS: In a porcine model of coronary restenosis, a novel polymer-free DES using nitrogen-doped TiO2 film deposition shows higher biocompatibility and compares favorably with a commercial DES.

Acetylcholine rescues two-cell block through activation of IP3 receptors and Ca2+/calmodulin-dependent kinase II in an ICR mouse strain.

Acetylcholine (ACh) causes early activation events in mouse oocytes, but little is known about its precise role in the early embryonic development of mice. We aimed to determine whether and how ACh is capable of rescuing two-cell block in an in vitro culture system. ACh evoked different transient Ca(2+) patterns showing a higher Ca(2+) peak in the two-cell stage embryos (two-cells) than observed in mature oocytes. In early two-cells subjected to an in vitro two-cell block, xestospongin C (Xes-C), an IP3 receptor antagonist, significantly decreased the level of the ACh-induced Ca(2+) increase. The reduction in the ACh-induced Ca(2+) increase by Xes-C in late two-cells was lower than that in early two-cells. Furthermore, KN62 and KN93, both CaMKII inhibitors, were found to reduce the magnitude of the ACh-induced Ca(2+) increase in early two-cells. The addition of ACh to the culture medium showed an ability to rescue in vitro two-cell block. However, the addition of ACh together with both Xes-C and CaMKII inhibitors or with either inhibitor separately had no effect on the rescue of two-cell block. Long-term exposure of late two-cells to ACh decreased morula and early blastocyst development and ACh had a differential effect on early and late two-cells. These results indicate that ACh likely rescues the in vitro two-cell block through activation of IP3R- and/or CaMKII-dependent signal transduction pathways.

Expression of thermosensitive two-pore domain K+ channels in human keratinocytes cell line HaCaT cells.

Recent studies have shown that keratinocytes can sense temperature via thermo-transient receptor potential (TRP) channels. It is not known whether other thermosensitive ion channels such as TREK-1, TREK-2 and TRAAK (TREKs/TRAAK) that are members of the two-pore domain K(+) (K(2P)) channel family are expressed in human keratinocytes. Here, we identified the expression of TREKs/TRAAK in human keratinocytes-derived cell line HaCaT cells using RT-PCR, immunocytochemistry, Western blot analysis and patch-clamp technique. RT-PCR showed that all six K(2P) channels tested (TASK-1, TASK-3, TREK-1, TREK-2, TRAAK and TASK-2) were expressed in HaCaT cells, as well as in skin and dorsal root ganglion (DRG) of rat. The expression of TREKs/TRAAK mRNA identified by RT-PCR was further studied at the protein level. Using anti-TREK-1, -TREK-2 and -TRAAK, bands of approximately 46, approximately 60 and approximately 43 kDa, respectively, were observed at plasma membrane of HaCaT cells. Immunostaining also showed that TREK-1, TREK-2 and TRAAK were expressed in all area of cells including plasma membrane. Whole-cell K(+) currents recorded from HaCaT cells were activated by arachidonic acid and heat. These results suggest that TREKs/TRAAK channels could act as thermosensors in human keratinocytes.

Improvement of oxidative decomposition of aqueous phenol by microwave irradiation in UV/H2O2 process and kinetic study.

2.5GHz of microwave irradiation can cause a considerable improvement of oxidative decomposition of aqueous phenol in a UV/H2O2 system. The experimental results showed that the microwave irradiation can raise both the phenol conversion and the TOC removal efficiency up to or above 50%. Also, the microwave irradiation could considerably enhance the oxidative degradation of phenol in the UV/H2O2 system even under a suppression of thermal effect. Addition of hydrogen peroxide by more than a stoichiometric amount was critical to mineralize aqueous phenol to create a short reaction time. Also, microwave irradiation can accelerate the degradation rate of intermediates, hydroquinone and catechol, produced in the course of phenol oxidative decomposition. From the kinetic study, the disappearance rate of phenol can be expressed as dX/dt = kPH[M]0(alpha - X)(1 - X), where alpha equivalent [H2O2]0/[M]0 + kOH[OH*]/kPH[M]0, shows a good correlation with the experimental data. The kinetic analysis showed that an indirect reaction of phenol with OH radical might be dominant in the absence of microwave irradiation, meanwhile a direct reaction of phenol with hydrogen peroxide might be dominant in the presence of microwave irradiation except for low concentrations of hydrogen peroxide.