Alloying Matters for Ordering: Synthesis of Highly Ordered PtCo Intermetallic Catalysts for Fuel Cells.

Porous carbon-supported atomically ordered intermetallic compounds (IMCs) are promising electrocatalysts in boosting oxygen reduction reaction (ORR) for fuel cell applications. However, the formation mechanism of IMC structures under high temperatures is poorly understood, which hampers the synthesis of highly ordered IMC catalysts with promoted ORR performance. Here, we employ high-temperature X-ray diffraction and energy-dispersive spectroscopic elemental mapping techniques to study the formation process of IMCs, by taking PtCo for example, in an industry-relevant impregnation synthesis. We find that high-temperature annealing is crucial in promoting the formation of alloy particles with a stoichiometric Co/Pt ratio, which in turn is the precondition for transforming the disordered alloys to ordered intermetallic structures at a relatively low temperature. Based on the findings, we accordingly synthesize highly ordered L10-type PtCo catalysts with a remarkable ORR performance in fuel cells.

Formation of nuclear condensates by the Mediator complex subunit Med15 in mammalian cells.

BACKGROUND: The Mediator complex is an evolutionarily conserved multi-subunit protein complex that plays major roles in transcriptional activation and is essential for cell growth, proliferation, and differentiation. Recent studies revealed that some Mediator subunits formed nuclear condensates that may facilitate enhancer-promoter interactions and gene activation. The assembly, regulation, and functions of these nuclear condensates remain to be further understood. RESULTS: We found that Med15, a subunit in the tail module of the Mediator complex, formed nuclear condensates through a novel mechanism. Nuclear foci of Med15 were detected by both immunostaining of endogenous proteins and live cell imaging. Like Med1 foci and many other biomolecular condensates, Med15 foci were sensitive to 1, 6-Hexanediol and showed rapid recovery during fluorescence recovery after photobleaching. Interestingly, overexpressing DYRK3, a dual-specificity kinase that controls the phase transition of membraneless organelles, appeared to disrupt Med1 foci and Med15 foci. We identified two regions that are required to form Med15 nuclear condensates: the glutamine-rich intrinsically disordered region (IDR) and a short downstream hydrophobic motif. The optodroplet assay revealed that both the IDR and the C-terminal region of Med15 contributed to intracellular phase separation. CONCLUSIONS: We identified that the Mediator complex subunit Med15 formed nuclear condensates and characterized their features in living cells. Our work suggests that Med15 plays a role in the assembly of transcription coactivator condensates in the nucleus and identifies Med15 regions that contribute to phase separation.

High-Temperature Synthesis of Small-Sized Pt/Nb Alloy Catalysts on Carbon Supports for Hydrothermal Reactions.

Catalytic biomass conversions are sustainable processes to produce value-added fuels and chemicals but need stable catalysts that can tolerate harsh hydrothermal conditions. Herein, we report a hydrothermally stable catalyst by alloying Pt with a high-melting-point metal Nb. The Pt/Nb alloy catalysts are prepared by H2 reduction at a high temperature of 900 °C with a high-surface-area carbon black support, which can suppress metal sintering at high temperatures and thus lead to small-sized alloyed Pt/Nb particles of only 2.2 nm. Taking the advantages of surface acid property provided by the Nb sites and the size effect, the prepared C-supported small-sized Pt/Nb alloy catalysts exhibit attractive activities for the hydrogenation of levulinic acid into γ-valerolactone and the water-gas shift reaction. More significantly, benefiting from the inherent stability of high-melting-point Nb, the Pt/Nb alloy catalysts show much enhanced hydrothermal stability compared to commercial Pt/C and Ru/C catalysts.

Automatic detection of sleep apnea based on EEG detrended fluctuation analysis and support vector machine.

Sleep apnea syndrome (SAS) is prevalent in individuals and recently, there are many studies focus on using simple and efficient methods for SAS detection instead of polysomnography. However, not much work has been done on using nonlinear behavior of the electroencephalogram (EEG) signals. The purpose of this study is to find a novel and simpler method for detecting apnea patients and to quantify nonlinear characteristics of the sleep apnea. 30 min EEG scaling exponents that quantify power-law correlations were computed using detrended fluctuation analysis (DFA) and compared between six SAS and six healthy subjects during sleep. The mean scaling exponents were calculated every 30 s and 360 control values and 360 apnea values were obtained. These values were compared between the two groups and support vector machine (SVM) was used to classify apnea patients. Significant difference was found between EEG scaling exponents of the two groups (p < 0.001). SVM was used and obtained high and consistent recognition rate: average classification accuracy reached 95.1% corresponding to the sensitivity 93.2% and specificity 98.6%. DFA of EEG is an efficient and practicable method and is helpful clinically in diagnosis of sleep apnea.

Red blood cell distribution width predicts survival in patients with Eisenmenger syndrome.

BACKGROUND: Previous studies identified an independent relationship between red blood cell distribution width (RDW) and prognosis in patients with pulmonary hypertension of mixed etiologies and idiopathic pulmonary arterial hypertension. This study aimed to investigate the significance of RDW for predicting survival in patients with Eisenmenger syndrome (ES). METHODS: We retrospectively reviewed the clinical records and collected baseline data for patients newly diagnosed with ES in our hospital between January 2005 and October 2009. Follow-up data were collected periodically using a specifically designed network database until December 31, 2012. The end point was all-cause death. RESULTS: A total of 109 patients with ES were included in the study. Twenty-one patients (19.3%) died during a median follow-up period of 4.2 years (interquartile range 3.7-5.0 years). Baseline RDW was significantly correlated with mixed venous oxygen saturation (r=-0.286, p=0.003), arterial oxygen saturation (r=-0.423, p<0.001), mean pulmonary arterial pressure (r=0.271, p=0.004) and total pulmonary resistance (r=0.465, p<0.001). The 1-, 3- and 5-year survival rates for all 109 patients were 94%, 87% and 78%, respectively. Kaplan-Meier analysis showed that patients with RDW ≥13.9% had a lower survival rate than patients with RDW <13.9% (p=0.001). Multivariate Cox regression analysis showed that RDW was an independent prognostic marker in ES, with a hazard ratio of 1.162 (95% CI 1.036-1.302; p=0.010). CONCLUSIONS: Baseline RDW correlates with hemodynamics and is an independent prognostic marker in ES.

Prognostic relevance of ventricular arrhythmias in surgical patients with gastrointestinal tumors.

BACKGROUND: Individuals diagnosed with gastrointestinal tumors are at an increased risk of developing cardiovascular diseases. Among which, ventricular arrhythmia is a prevalent clinical concern. This suggests that ventricular arrhythmias may have predictive value in the prognosis of patients with gastrointestinal tumors. AIM: To explore the prognostic value of ventricular arrhythmias in patients with gastrointestinal tumors receiving surgery. METHODS: We retrospectively analyzed data from 130 patients undergoing gastrointestinal tumor resection. These patients were evaluated by a 24-h ambulatory electrocardiogram (ECG) at the Sixth Affiliated Hospital of Sun Yat-sen University from January 2018 to June 2020. Additionally, 41 general healthy age-matched and sex-matched controls were included. Patients were categorized into survival and non-survival groups. The primary endpoint was all-cause mortality, and secondary endpoints included major adverse cardiovascular events (MACEs). RESULTS: Colorectal tumors comprised 90% of cases. Preoperative ambulatory ECG monitoring revealed that among the 130 patients with gastrointestinal tumors, 100 (76.92%) exhibited varying degrees of premature ventricular contractions (PVCs). Ten patients (7.69%) manifested non-sustained ventricular tachycardia (NSVT). The patients with gastrointestinal tumors exhibited higher PVCs compared to the healthy controls on both conventional ECG [27 (21.3) vs 1 (2.5), P = 0.012] and 24-h ambulatory ECG [14 (1.0, 405) vs 1 (0, 6.5), P < 0.001]. Non-survivors had a higher PVC count than survivors [150.50 (7.25, 1690.50) vs 9 (0, 229.25), P = 0.020]. During the follow-up period, 24 patients died and 11 patients experienced MACEs. Univariate analysis linked PVC > 35/24 h to all-cause mortality, and NSVT was associated with MACE. However, neither PVC burden nor NSVT independently predicted outcomes according to multivariate analysis. CONCLUSION: Patients with gastrointestinal tumors exhibited elevated PVCs. PVCs > 35/24 h and NSVT detected by 24-h ambulatory ECG were prognostically significant but were not found to be independent predictors.

Promoting ordering degree of intermetallic fuel cell catalysts by low-melting-point metal doping.

Carbon supported intermetallic compound nanoparticles with high activity and stability are promising cathodic catalysts for oxygen reduction reaction in proton-exchange-membrane fuel cells. However, the synthesis of intermetallic catalysts suffers from large diffusion barrier for atom ordering, resulting in low ordering degree and limited performance. We demonstrate a low-melting-point metal doping strategy for the synthesis of highly ordered L10-type M-doped PtCo (M = Ga, Pb, Sb, Cu) intermetallic catalysts. We find that the ordering degree of the M-doped PtCo catalysts increases with the decrease of melting point of M. Theoretic studies reveal that the low-melting-point metal doping can decrease the energy barrier for atom diffusion. The prepared highly ordered Ga-doped PtCo catalyst exhibits a large mass activity of 1.07 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a rated power density of 1.05 W cm-2 in H2-air fuel cells, with a Pt loading of 0.075 mgPt cm-2.

Atorvastatin in pulmonary arterial hypertension (APATH) study.

Statins have been shown to both prevent and attenuate pulmonary hypertension in animal models. This study investigates the potential therapeutic benefits of atorvastatin as an affordable treatment for pulmonary hypertension patients. 220 patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) were randomised, double-blind, to receive atrovastatin 10 mg daily or matching placebo in addition to supportive care. At 6 months, 6-min walk distance decreased by 16.6 m in the atorvastatin group and 14.1 m in the placebo group. The mean placebo-corrected treatment effect was -2.5 m (95% CI: -38-33; p=0.96), based on intention to treat. A small nonsignificant increase in pulmonary vascular resistance and fall in cardiac output was seen in both treatment groups. There was no significant difference in the proportion of patients who improved, remained stable or showed a deterioration in World Health Organization functional class between atorvastatin and placebo treatments. Nine patients died in the atorvastatin group and 11 in the placebo group. Serum cholesterol levels fell significantly on atorvastatin treatment. Discontinuation rates were 23.2% and 26.9% on atorvastatin and placebo, respectively. Atorvastatin 10 mg daily has no beneficial effect on the natural history of PAH or CTEPH over 6 months.

[Screening study of pulmonary arterial hypertension in patients with congenital heart diseases].

OBJECTIVE: To determine the prevalence and influencing factors of pulmonary arterial hypertension (PAH) in patients with congenital heart disease (CHD). METHODS: Between May 2007 and December 2008, a total of 692 CHD patients admitted into Fuwai Hospital were prospectively enrolled. Doppler echocardiography was employed to measure the level of pulmonary artery systolic pressure (PASP). PAH occurred when there was an increase in PASP > 40 mm Hg (1 mm Hg = 0.133 kPa) at rest. Eisenmenger syndrome was defined when there was a reversed (pulmonary-to-systemic) or bidirectional shunt. The clinical characteristics between the patients with/without PAH and Eisenmenger syndrome were compared and their risk factors analyzed with a multivariate Logistic model. RESULTS: The underlying conditions included atrial septal defect (n = 187, 27.0%), ventricular septal defect (n = 456, 65.9%) and patent ductus arteriosus (n = 49, 7.1%). The numbers of patients with PAH-CHD and Eisenmenger syndrome were 329 (47.5%) and 105 (15.2%) respectively. Among the PAH-CHD patients, 31.9% of them had Eisenmenger syndrome. The patients with large shunts were at an elevated risk of PAH. Logistic regression analysis showed that advanced age was an independent risk factor of PAH (OR = 1.04, P < 0.001). Compared with atrial septal defect, ventricular septal defect and patent ductus arteriosus increased the risks of PAH (OR = 2.78, P < 0.001 and OR = 2.50, P < 0.001 respectively). CONCLUSIONS: PAH is a common complication in CHD patients. And ventricular septal defect is the most common pathogenic type of PAH. Advanced age, ventricular septal defect and patent ductus arteriosus are the risk factors of PAH.

[Multicenter study of disease attributes in adult patients with pulmonary hypertension].

OBJECTIVE: To understand the demographic, hemodynamic and clinical features of adult patients with pulmonary hypertension (PH) in China. METHODS: Between May 2007 and October 2010, a total of 551 adult PH patients were recruited from 31 clinical centers all over China. All fulfilled the traditional hemodynamic criteria diagnosed through right heart catheterization (RHC). The relevant data of demographic, clinical and hemodynamic features of all patients, analyzed the similarities and differences of demographic characteristics between different subtypes. They were divided into 2 groups: WHO functional class I/II and III/IV. And their hemodynamic and clinical features were compared. RESULTS: There were 165 males and 386 females with a mean age of (35 ± 12) years. The mean body mass index (BMI) was (21 ± 4) kg/m(2). There were pulmonary arterial hypertension (PAH, n = 487) and chronic thromboembolic pulmonary hypertension (CTEPH, n = 64). Fatigue (421, 76.4%) and dyspnea (398, 72.2%) were the most common symptoms; Physical examination revealed such a common sign as an accentuated pulmonic second sound (P(2)) in 510 patients (92.6%). Over half (325, 59.0%) of them were of WHO functional class II and 213 (38.6%) patients functional class III. The 6-minute walking distance (6MWD) and Borg dyspnea score were (352 ± 91) m and 3.0 (2.0 - 4.0) respectively. ECG of 497 (90.2%) patients showed right ventricular hypertrophy. Mean right atrial pressure was (9 ± 6) mm Hg (1 mm Hg = 0.133 kPa), pulmonary arterial pressure (67 ± 20) mm Hg, cardiac index (2.7 ± 1.2) Lmin(-1)m(-2) and pulmonary vascular resistance (1496 ± 783) dyn.sec.cm(-5). CONCLUSIONS: Young females with a low BMI are predominantly affected by PH. Severe functional and hemodynamic compromises often appear on presentation. And hemodynamic impairment is correlated with 6MWD and WHO functional class.

[Clinical analysis of 150 patients with idiopathic pulmonary arterial hypertension].

OBJECTIVE: To explore the demographic characteristics and clinical features of patients with idiopathic pulmonary arterial hypertension (IPAH) in China. METHODS: Between March 2007 and September 2010, IPAH diagnosis was confirmed by right heart catheterization in 150 adult patients from 31 clinical centers in China. Clinical and hemodynamic data were analyzed and patients were divided into WHO functional class I/II and WHO functional class III/IV group. RESULTS: The mean age of 150 patients were 36 ± 13 years with female patient/male patient ratio of 2:1, and mean BMI was (21.3 ± 3.5) kg/m(2). Fatigue (n = 123, 82.0%) and dyspnea (n = 112, 74.7%) are the most common symptoms. Accentuated pulmonic second sound (P(2)) was detected in 92.0% (n = 138) of patients during physical examination, which was also the most common sign. About 49.0% (n = 73) patients were WHO functional class I/II patients and 46.0% (n = 68) patients were WHO functional class III/IV patients. Six minutes walking distance (6MWD) and Borg dyspnea score was (337 ± 101) m and 2.0 (2.0, 4.0), respectively. Right ventricular hypertrophy was suggested by ECG in 93.1% (n = 140) patients. Right atrial pressure was (10 ± 6) mm Hg, mean pulmonary artery pressure was (61 ± 16) mm Hg, cardiac index was (2.3 ± 0.8) L×min(-1)×m(-2) and pulmonary vascular resistance (1484 ± 699) dyn×s(-1)×cm(-5) in this cohort. 6 MWD (305 m ± 89 m vs. 377 m ± 88 m) was significantly shorter while Borg dyspnea score [3.0 (3.0, 5.0) vs. 2.0 (2.0, 3.0)] was significantly higher in WHO functional class III/IV patients than in WHO functional class I/II patients. Similarly hemodynamic parameters were also worse in WHO functional class III/IV patients than in WHO functional class I/II patients (all P < 0.05). CONCLUSION: Idiopathic pulmonary arterial hypertension patients in this cohort affect mostly young adults, dominated by female gender and lower body mass index. Fatigue and dyspnea are the most common symptoms and accentuated pulmonic second sound (P(2)) is the most common sign. IPAH patients are often displaying severe functional and hemodynamic disturbance at first visit to hospitals. Dyspnea and hemodynamic impairment are related to 6MWD and WHO functional class.

Phase diagrams guide synthesis of highly ordered intermetallic electrocatalysts: separating alloying and ordering stages.

Supported platinum intermetallic compound catalysts have attracted considerable attention owing to their remarkable activities and durability for the oxygen reduction reaction in proton-exchange membrane fuel cells. However, the synthesis of highly ordered intermetallic compound catalysts remains a challenge owing to the limited understanding of their formation mechanism under high-temperature conditions. In this study, we perform in-situ high-temperature X-ray diffraction studies to investigate the structural evolution in the impregnation synthesis of carbon-supported intermetallic catalysts. We identify the phase-transition-temperature (TPT)-dependent evolution process that involve concurrent (for alloys with high TPT) or separate (for alloys with low TPT) alloying/ordering stages. Accordingly, we realize the synthesis of highly ordered intermetallic catalysts by adopting a separate annealing protocol with a high-temperature alloying stage and a low-temperature ordering stage, which display a high mass activity of 0.96 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a remarkable durability.

[Effect of Special Structure Bi-Specific Chimeric Antigen Receptor T Cell on Tumor Cells].

OBJECTIVE: To explore and design a novel bi-specific chimeric antigen receptor (CAR) structure. To obtain the corresponding CAR-T cells and verify killing effects on tumor cells in vitro and in vivo. METHODS: Five kinds of bi-specific CAR structures including humanized CD19 scFv and CD79b scFv, CD8 hinge & TM-4-1BB-CD3ζ and/or CD3ε chain intracellular regions were constructed and prepared. CAR-19-79b cells were obtained. Five kinds of CAR-T cells were co-incubated with the 3M-CD19-CD79b-Luc target cells. Luciferase assay and ELISA were used to detecte the killing ability of these five groups of CAR-T cells and the secretion of cytokines and compared. The optimal structure of CAR-T cells was used to treat the leukemia mouse model constructed by Daudi-Luc cells. And the treatment efficacy was evaluated. At the same time, other targets were used in this structure. With the same methods, the stability and effectiveness of the structure were verified. RESULTS: CAR-19-79b-T cells were cultured for 7 days, the expression rates of CAR-19 and CAR-79b were 21.6%-36.3% and 21.7%-37.8%, respectively. The killing rates of 5 kinds of CAR-19-79b-T cells prepared by T cells from 3 healthy donors on 3M-CD19-CD79b-Luc cells were significantly higher than those of the T cell control group at the effect-target ratio of 10∶1. Among them, the killing rates of CAR-19-79b-T cells with No. III and No. IV structures were the strongest. After co-incubation with 3M-CD19-CD79b-Luc target cells, the amount of IFN-γ and TNF-α secreted by CAR-T cells with CAR IV and CARV structures was the lowest. And there was no significance between the two groups (P>0.05). CAR IV cells with remarkable killing effect and low secretion factor had obvious therapeutic effect on Daudi-Luc leukemia mice, extending the survival period of mice to 64 days. And all mice in the T cell control group died at 41.0±2.4 days. The CAR-19-BCMA-T and CAR-19-22-T with the same structure showed significant killing ability and low cytokine expression levels. CONCLUSION: A novel bi-specific CAR structures was successfully designed, which could efficiently kill the corresponding tumor cells and secrete less cytokines (such as TNF-α, IFN-γ). Moreover, it shows obvious therapeutic effect on Daudi lymphoma mouse model. The bi-specific CAR structure shows good killing specificity and safety.

Small molecule-assisted synthesis of carbon supported platinum intermetallic fuel cell catalysts.

Supported ordered intermetallic compounds exhibit superior catalytic performance over their disordered alloy counterparts in diverse reactions. But the synthesis of intermetallic compounds catalysts often requires high-temperature annealing that leads to the sintering of metals into larger crystallites. Herein, we report a small molecule-assisted impregnation approach to realize the general synthesis of a family of intermetallic catalysts, consisting of 18 binary platinum intermetallic compounds supported on carbon blacks. The molecular additives containing heteroatoms (that is, O, N, or S) can be coordinated with platinum in impregnation and thermally converted into heteroatom-doped graphene layers in high-temperature annealing, which significantly suppress alloy sintering and insure the formation of small-sized intermetallic catalysts. The prepared optimal PtCo intermetallics as cathodic oxygen-reduction catalysts exhibit a high mass activity of 1.08 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a rated power density of 1.17 W cm-2 in H2-air fuel cells.

[Accuracy of transthoracic Doppler echocardiography in the estimation of pulmonary artery systolic pressures].

OBJECTIVE: To investigate the qualitative accuracy of pulmonary artery systolic pressure (PASP) as estimated by transthoracic Doppler echocardiography (TDE). METHODS: A retrospective study was conducted on 102 adult patients with idiopathic pulmonary arterial hypertension undergoing Doppler echocardiography within 72 hours prior to right heart catheterization. During this period, all patients were stable without any specific drug therapy. Compared with right heart catheterization, the accuracy of PASP as measured by TDE was evaluated. RESULTS: Among them, there were 38 males and 64 females with an average age of (31 ± 11) years old (range: 18 - 59 years old). There was a moderate correlation between the measurements of PASP by TDE and right heart catheterization (r = 0.64, P < 0.01). Through the analysis of Bland-Altman, the bias for the TDE estimates of PASP was 6.7 mm Hg with a 95% limit of agreement ranging from -47.6 to 34.3 mm Hg. There were 60 (58.8%) cases with absolute differences over 10 mm Hg between two methods. Overestimation and underestimation of PASP by TDE occurred in 15.7% (16/102) and 43.1% (44/102) respectively. The magnitude of pressure underestimation and overestimation was insignificant [(25 ± 12) vs (26 ± 16) mm Hg, P = 0.765]. The probability of underestimate was higher than that of overestimate. As to the corresponding diagnostic categories of severity that each subject would fall into for each technique, the diagnostic categories of 16 overestimated patients were in accordance. Among 44 underestimated patients, 9 (20.5%) had their pressure underestimated within one diagnostic category (minor error) while 2 (4.5%) were within two diagnostic categories (major error). CONCLUSION: Due to a frequent rate of inaccurate estimation of PASP, TDE can not replace right heart catheterization. TDE tends to underestimate PASP and results in a diagnostic misclassification of degree.

[Sildenafil therapy for pulmonary hypertension: a prospective study].

OBJECTIVE: To explore the safety and efficacy of oral sildenafil therapy for pulmonary arterial hypertension (PAH), and to provide evidence for sildenafil treatment for Chinese patients with PAH. METHODS: In this 12-week, prospective, open-label, uncontrolled study, 56 patients with PAH were given oral sildenafil (25 mg, tid). The primary end point was change from baseline to 12 weeks in exercise capacity assessed by 6 min walk (6MW) test. Secondary end points included changes in WHO class and cardiopulmonary hemodynamics. Clinical worsening was defined as death, transplantation, hospitalization for PAH, or initiation of additional therapies for PAH, such as intravenous epoprostenol or oral bosentan. RESULTS: After 12 weeks, the compliance was good in 56 patients. Significant improvement was seen in NYHA heart function class and WHO class as compared to baseline (P < 0.01): from class IV to class III in 2, from class III to class II in 8 and to class I in 2 cases, and from class II to class I in 5 cases. No NYHA heart function class and WHO PAH function class deterioration were observed. Oral sildenafil increased 6MW distance, from (352 ± 80) m to (396 ± 78) m, with a change of (44 ± 70) m (P < 0.01). Significant improvement was seen in hemodynamics (mean pulmonary artery pressure, P < 0.01; cardiac index, P < 0.01; pulmonary vascular resistance, P < 0.01) at week 12 as compared with baseline. Mean right atrial pressure decreased (3 ± 11) mm Hg (1 mm Hg = 0.133 kPa), mean pulmonary arterial pressure decreased (6 ± 14) mm Hg, cardiac output increased (1.1 ± 2.0) L/min, cardiac index increased (0.7 ± 1.1) L×min(-1)×m(-2), and total pulmonary resistance decreased (490 ± 831) Dys×s×cm(-5). Side effects were mild and consistent with those reported with sildenafil treatment. No statistically significant clinical worsening was observed with sildenafil therapy for PAH patients. CONCLUSIONS: Sildenafil improves exercise capacity, WHO functional class, and hemodynamics in patients with pulmonary arterial hypertension.

Initiation of stress granule assembly by rapid clustering of IGF2BP proteins upon osmotic shock.

Stress granules (SGs) are membraneless organelles formed in the cytoplasm by liquid-liquid phase separation (LLPS) of translationally-stalled mRNA and RNA-binding proteins during stress response. Understanding the mechanisms governing SG assembly requires imaging SG formation in real time. Although numerous SG proteins have been identified, the kinetics of their recruitment during SG assembly has not been well established. Here we used live cell imaging and super-resolution imaging to visualize SG assembly in human cells. We found that IGF2BP proteins formed microscopically visible clusters in living cells almost instantaneously after osmotic stress, followed by fusion of clusters and the recruitment of G3BP1 and TIA1. Rapid clustering of IGF2BP1 was reduced in cells pretreated with emetine that stabilizes polysomes on mRNA. The KH3/4 di-domain and an intrinsically disordered region (IDR) of IGF2BP1 were found to mediate its clustering. Super-resolution imaging confirmed the formation of IGF2BP clusters associated with mRNA at 40 s after osmotic stress. In mature SGs, multiple clusters of poly(A) mRNA were found to associate with the periphery and the interior of a dense granule formed by IGF2BP1. Taken together, our findings revealed a novel, multi-stage LLPS process during osmotic stress, in which rapid clustering of IGF2BP proteins initiates SG assembly.

Dehydroepiandrosterone attenuates pulmonary artery and right ventricular remodeling in a rat model of pulmonary hypertension due to left heart failure.

AIM: Pulmonary hypertension due to left heart failure (PH-LHF) is the most common cause of pulmonary hypertension. However, therapies for PH-LHF are lacking. Therefore, we investigated the effects and potential mechanism of dehydroepiandrosterone (DHEA) treatment in an experimental model of PH-LHF. MAIN METHOD: PH-LHF was induced in rats via ascending aortic banding. The rats then received daily DHEA from Day 1 to Day 63 for the prevention protocol or from Day 49 to Day 63 for the reversal protocol. Other ascending aortic banding rats were left untreated to allow development of PH and right ventricular (RV) failure. Sham ascending aortic banding rats served as controls. KEY FINDING: Significant increases in mean pulmonary arterial pressure (mPAP) and right ventricular end-diastolic diameter (RVEDD) were observed in the PH-LHF group. Therapy with DHEA prevented LHF-induced PH and RV failure by preserving mPAP and preventing RV hypertrophy and pulmonary artery remodeling. In preexisting severe PH, DHEA attenuated most lung and RV abnormalities. The beneficial effects of DHEA in PH-LHF seem to result from depression of the STAT3 signaling pathway in the lung. SIGNIFICANT: DHEA not only prevents the development of PH-LHF and RV failure but also rescues severe preexisting PH-LHF.

Microglia Are Indispensable for Synaptic Plasticity in the Spinal Dorsal Horn and Chronic Pain.

Spinal long-term potentiation (LTP) at C-fiber synapses is hypothesized to underlie chronic pain. However, a causal link between spinal LTP and chronic pain is still lacking. Here, we report that high-frequency stimulation (HFS; 100 Hz, 10 V) of the mouse sciatic nerve reliably induces spinal LTP without causing nerve injury. LTP-inducible stimulation triggers chronic pain lasting for more than 35 days and increases the number of calcitonin gene-related peptide (CGRP) terminals in the spinal dorsal horn. The behavioral and morphological changes can be prevented by blocking NMDA receptors, ablating spinal microglia, or conditionally deleting microglial brain-derived neurotrophic factor (BDNF). HFS-induced spinal LTP, microglial activation, and upregulation of BDNF are inhibited by antibodies against colony-stimulating factor 1 (CSF-1). Together, our results show that microglial CSF1 and BDNF signaling are indispensable for spinal LTP and chronic pain. The microglia-dependent transition of synaptic potentiation to structural alterations in pain pathways may underlie pain chronicity.

Topical delivery of l-theanine ameliorates TPA-induced acute skin inflammation via downregulating endothelial PECAM-1 and neutrophil infiltration and activation.

l-theanine, the most abundant free amino acid in tea, has been documented to possess many different bioactive properties through oral or intragastrical delivery. However, little is known about the effect of topical delivery of l-theanine on acute inflammation. In the present study, by using 12-O-tetradecanoylphorbol-13-acetate (TPA, 2.5 µg/ear)-induced ear edema model in mice, we first found that single-dose local pretreatment of l-theanine 30 min before TPA time- and dose-dependently suppressed the increases in both skin thickness and weight. Subsequently l-theanine ameliorated TPA-induced erythema, vascular permeability increase, epidermal and dermal hyperplasia, neutrophil infiltration and activation via downregulating the expression of PECAM-1 (a platelet endothelial adhesion molecule-1) in blood vessels and the production of pro-inflammatory cytokines IL-1ß, TNF-α, and mediator cyclooxygenase-2 (COX-2), which is mainly expressed in neutrophils. It highlighted the potential of l-theanine as a locally administrable therapeutic agent for acute cutaneous inflammation.