A 0.6 Mpc H I structure associated with Stephan's Quintet.

Stephan's Quintet (SQ, co-moving radial distance = 85 ± 6 Mpc, taken from the NASA/IPAC Extragalactic Database (NED)1) is unique among compact groups of galaxies2-12. Observations have previously shown that interactions between multiple members, including a high-speed intruder galaxy currently colliding into the intragroup medium, have probably generated tidal debris in the form of multiple gaseous and stellar filaments6,8,13, the formation of tidal dwarfs7,14,15 and intragroup-medium starbursts16, as well as widespread intergalactic shocked gas5,10,11,17. The details and timing of the interactions and collisions remain poorly understood because of their multiple nature18,19. Here we report atomic hydrogen (H I) observations in the vicinity of SQ with a smoothed sensitivity of 1σ = 4.2 × 1016 cm-2 per channel (velocity bin-width Δv = 20 km s-1; angular resolution = 4'), which are about two orders of magnitude deeper than previous observations8,13,20,21. The data show a large H I structure (with linear scale of around 0.6 Mpc) encompassing an extended source of size approximately 0.4 Mpc associated with the debris field and a curved diffuse feature of length around 0.5 Mpc attached to the south edge of the extended source. The diffuse feature was probably produced by tidal interactions in early stages of the formation of SQ (>1 Gyr ago), although it is not clear how the low-density H I gas (NH i ≲ 1018 cm-2) can survive the ionization by the intergalactic ultraviolet background on such a long time scale. Our observations require a rethinking of properties of gas in outer parts of galaxy groups and demand complex modelling of different phases of the intragroup medium in simulations of group formation.

Migrating Myeloid Cells Sense Temporal Dynamics of Chemoattractant Concentrations.

Chemoattractant-mediated recruitment of hematopoietic cells to sites of pathogen growth or tissue damage is critical to host defense and organ homeostasis. Chemotaxis is typically considered to rely on spatial sensing, with cells following concentration gradients as long as these are present. Utilizing a microfluidic approach, we found that stable gradients of intermediate chemokines (CCL19 and CXCL12) failed to promote persistent directional migration of dendritic cells or neutrophils. Instead, rising chemokine concentrations were needed, implying that temporal sensing mechanisms controlled prolonged responses to these ligands. This behavior was found to depend on G-coupled receptor kinase-mediated negative regulation of receptor signaling and contrasted with responses to an end agonist chemoattractant (C5a), for which a stable gradient led to persistent migration. These findings identify temporal sensing as a key requirement for long-range myeloid cell migration to intermediate chemokines and provide insights into the mechanisms controlling immune cell motility in complex tissue environments.

The gravitationally unstable gas disk of a starburst galaxy 12 billion years ago.

Galaxies in the early Universe that are bright at submillimetre wavelengths (submillimetre-bright galaxies) are forming stars at a rate roughly 1,000 times higher than the Milky Way. A large fraction of the new stars form in the central kiloparsec of the galaxy1-3, a region that is comparable in size to the massive, quiescent galaxies found at the peak of cosmic star-formation history4 and the cores of present-day giant elliptical galaxies. The physical and kinematic properties inside these compact starburst cores are poorly understood because probing them at relevant spatial scales requires extremely high angular resolution. Here we report observations with a linear resolution of 550 parsecs of gas and dust in an unlensed, submillimetre-bright galaxy at a redshift of z = 4.3, when the Universe was less than two billion years old. We resolve the spatial and kinematic structure of the molecular gas inside the heavily dust-obscured core and show that the underlying gas disk is clumpy and rotationally supported (that is, its rotation velocity is larger than the velocity dispersion). Our analysis of the molecular gas mass per unit area suggests that the starburst disk is gravitationally unstable, which implies that the self-gravity of the gas is stronger than the differential rotation of the disk and the internal pressure due to stellar-radiation feedback. As a result of the gravitational instability in the disk, the molecular gas would be consumed by star formation on a timescale of 100 million years, which is comparable to gas depletion times in merging starburst galaxies5.

[Predictive value of left ventricular ejection fraction reserve assessed by SPECT G-MPI for major adverse cardiovascular event in patients with coronary artery disease].

Objective: To evaluate the prognostic value of left ventricular ejection fraction (LVEF) reserve assessed by gated SPECT myocardial perfusion imaging (SPECT G-MPI) for major adverse cardiovascular event (MACE) in patients with coronary artery disease. Methods: This is a retrospective cohort study. From January 2017 to December 2019, patients with coronary artery disease and confirmed myocardial ischemia by stress and rest SPECT G-MPI, and underwent coronary angiography within 3 months were enrolled. The sum stress score (SSS) and sum resting score (SRS) were analyzed by the standard 17-segment model, and the sum difference score (SDS, SDS=SSS-SRS) was calculated. The LVEF at stress and rest were analyzed by 4DM software. The LVEF reserve (ΔLVEF) was calculated (ΔLVEF=stress LVEF-rest LVEF). The primary endpoint was MACE, which was obtained by reviewing the medical record system or by telephone follow-up once every twelve months. Patients were divided into MACE-free and MACE groups. Spearman correlation analysis was used to analyze the correlation between ΔLVEF and all MPI parameters. Cox regression analysis was used to analyze the independent factors of MACE, and the optimal SDS cutoff value for predicting MACE was determined by receiver operating characteristic curve (ROC). Kaplan-Meier survival curves were plotted to compare the difference in the incidence of MACE between different SDS groups and different ΔLVEF groups. Results: A total of 164 patients with coronary artery disease [120 male; age (58.6±10.7) years] were included. The average follow-up time was (26.5±10.4) months, and a total of 30 MACE were recorded during follow-up. Multivariate Cox regression analysis showed that SDS (HR=1.069, 95%CI: 1.005-1.137, P=0.035) and ΔLVEF (HR=0.935, 95%CI: 0.878-0.995, P=0.034) were independent predictors of MACE. According to ROC curve analysis, the optimal cut-off to predict MACE was a SDS of 5.5 with an area under the curve of 0.63 (P=0.022). Survival analysis showed that the incidence of MACE was significantly higher in the SDS≥5.5 group than in the SDS<5.5 group (27.6% vs. 13.2%, P=0.019), but the incidence of MACE was significantly lower in the ΔLVEF≥0 group than in theΔLVEF<0 group (11.0% vs. 25.6%, P=0.022). Conclusions: LVEF reserve (ΔLVEF) assessed by SPECT G-MPI serves as an independent protective factor for MACE, while SDS is an independent risk predictor in patients with coronary artery disease. SPECT G-MPI is valuable for risk stratification by assessing myocardial ischemia and LVEF.

[Predictive value of the proportion of hibernating myocardium in total perfusion defect on reverse remodeling in patients with HFrEF underwent coronary artery bypass graft].

Objective: To evaluate the predictive value of the proportion of hibernating myocardium (HM) in total perfusion defect (TPD) on reverse left ventricle remodeling (RR) after coronary artery bypass graft (CABG) in patients with heart failure with reduced ejection fraction (HFrEF) by 99mTc-methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) combined with 18F-flurodeoxyglucose (FDG) gated myocardial imaging positron emission computed tomography (PET). Methods: Inpatients diagnosed with HFrEF at the Cardiac Surgery Center, Anzhen Hospital of Capital Medical University from January 2016 to January 2022 were prospectively recruited. MPI combined with 18F-FDG gated PET was performed before surgery for viability assessment and the patients received follow-up MPI and 18F-FDG gated PET at different stages (3-12 months) after surgery. Δ indicated changes (post-pre). Left ventricular end-systolic volume (ESV) reduced at least 10% was defined as RR, patients were divided into reverse remodeling (RR+) group and the non-reverse group (RR-). Binary logistic regression analysis was used to identify predictors of RR. Receiver operating characteristic (ROC) curve analysis was performed and the area under the curve (AUC) was calculated to assess the cut-off value for predicting RR. Additionally, we retrospectively enrolled inpatients with HFrEF at the Cardiac Surgery Center, Anzhen Hospital of Capital Medical University from January 2021 to January 2022 as the validation group, who underwent MPI and 18F-FDG gated PET before surgery. Echocardiography was performed before CABG and after CABG (3-12 months). In the validation group, the reliability of obtaining the cut-off value for the ROC curve was verified. Results: A total of 28 patients with HFrEF (26 males; age (56.9±8.7) years) were included in the prospective cohort. HM/TPD was significantly higher in the RR+ group than in the RR- group ((51.8%±17.9%) vs. (35.7%±13.9%), P=0.016). Binary logistic regression analysis revealed that HM/TPD was an independent predictor of RR (Odds ratio=1.073, 95% Confidence interval: 1.005-1.145, P=0.035). ROC curve analysis revealed that HM/TPD=38.3% yielded the highest sensitivity, specificity, and accuracy (all 75%) for predicting RR and the AUC was 0.786 (P=0.011). Meanwhile, a total of 100 patients with HFrEF (90 males; age (59.7±9.6) years) were included in the validation group. In the validation group, HM/TPD=38.3% predicted RR in HFrEF patients after CABG with the highest sensitivity, specificity and accuracy (82%, 60% and 73% respectively). Compared with the HFrEF patients in the HM/TPD<38.3% group (n=36), RR and cardiac function improved more significantly in the HM/TPD≥38.3% group (n=64) (all P<0.05). Conclusions: Preoperative HM/TPD ratio is an independent factor for predicting RR in patients with HFrEF after CABG, and HM/TPD≥38.3% can accurately predict RR and the improvement of cardiac function after CABG.

Utilizing flip angle/TR equivalence to reduce breath hold duration in hyperpolarized 129 Xe 1-point Dixon gas exchange imaging.

PURPOSE: To reduce scan duration in hyperpolarized 129 Xe 1-point Dixon gas exchange imaging by utilizing flip angle (FA)/TR equivalence. METHODS: Images were acquired in 12 subjects (n = 3 radiation therapy, n = 1 unexplained dyspnea, n = 8 healthy) using both standard (TR = 15 ms, FA = 20°, duration = 15 s, 998 projections) and "fast" (TR = 5.4 ms, FA = 12°, duration = 11.3 s, 2100 projections) acquisition parameters. For the fast acquisition, 3 image sets were reconstructed using subsets of 1900, 1500, and 1000 projections. From the resulting ventilation, tissue ("barrier"), and red blood cell (RBC) images, image metrics and biomarkers were compared to assess agreement between methods. RESULTS: Images acquired using both FA/TR settings had similar qualitative appearance. There were no significant differences in SNR, image mean, or image SD between images. Moreover, the percentage of the lungs in "defect", "normal", and "high" bins for each image (ventilation, RBC, barrier) was not significantly different among the acquisition types. After registration, comparison of 3D image metrics (Dice, volume similarity, average distance) agreed well between bins. Images using 1000 projections for reconstruction had no significant differences from images using all projections. CONCLUSION: Using flip angle/TR equivalence, hyperpolarized 129 Xe gas exchange images can be acquired via the 1-point Dixon technique in as little as 6 s, compared to ~15 s for previously reported parameter settings. The resulting images from this accelerated scan have no significant differences from the standard method in qualitative appearance or quantitative metrics.

Experimental Verification of Dissipation-Time Uncertainty Relation.

Dissipation is vital to any cyclic process in realistic systems. Recent research focus on nonequilibrium processes in stochastic systems has revealed a fundamental trade-off, called dissipation-time uncertainty relation, that entropy production rate associated with dissipation bounds the evolution pace of physical processes [Phys. Rev. Lett. 125, 120604 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.120604]. Following the dissipative two-level model exemplified in the same Letter, we experimentally verify this fundamental trade-off in a single trapped ultracold ^{40}Ca^{+} ion using elaborately designed dissipative channels, along with a postprocessing method developed in the data analysis, to build the effective nonequilibrium stochastic evolutions for the energy transfer between two heat baths mediated by a qubit. Since the dissipation-time uncertainty relation imposes a constraint on the quantum speed regarding entropy flux, our observation provides the first experimental evidence confirming such a speed restriction from thermodynamics on quantum operations due to dissipation, which helps us further understand the role of thermodynamical characteristics played in quantum information processing.

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation.

Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Although professional and non-professional macrophages reside in proximity in most tissues, whether they communicate with each other during cell clearance, and how this might affect inflammation, is not known. Here we show that macrophages, through the release of a soluble growth factor and microvesicles, alter the type of particles engulfed by non-professional phagocytes and influence their inflammatory response. During phagocytosis of apoptotic cells or in response to inflammation-associated cytokines, macrophages released insulin-like growth factor 1 (IGF-1). The binding of IGF-1 to its receptor on non-professional phagocytes redirected their phagocytosis, such that uptake of larger apoptotic cells was reduced whereas engulfment of microvesicles was increased. IGF-1 did not alter engulfment by macrophages. Macrophages also released microvesicles, whose uptake by epithelial cells was enhanced by IGF-1 and led to decreased inflammatory responses by epithelial cells. Consistent with these observations, deletion of IGF-1 receptor in airway epithelial cells led to exacerbated lung inflammation after allergen exposure. These genetic and functional studies reveal that IGF-1- and microvesicle-dependent communication between macrophages and epithelial cells can critically influence the magnitude of tissue inflammation in vivo.

Chatbot-mediated learning of cardiac auscultation.

Previous research suggested cardiac auscultation is underdeveloped in physicians-in-training. Developing proficiency requires wide exposure to signs, practice and feedback, which may not regularly occur in clinical environments. Our novel pilot study using a mixed-methods approach (n = 9) suggests chatbot-mediated learning of cardiac auscultation is accessible and possesses unique advantages, including immediate feedback, helping in the management of cognitive overload and facilitating deliberate practice.

Image- versus histogram-based considerations in semantic segmentation of pulmonary hyperpolarized gas images.

PURPOSE: To characterize the differences between histogram-based and image-based algorithms for segmentation of hyperpolarized gas lung images. METHODS: Four previously published histogram-based segmentation algorithms (ie, linear binning, hierarchical k-means, fuzzy spatial c-means, and a Gaussian mixture model with a Markov random field prior) and an image-based convolutional neural network were used to segment 2 simulated data sets derived from a public (n = 29 subjects) and a retrospective collection (n = 51 subjects) of hyperpolarized 129Xe gas lung images transformed by common MRI artifacts (noise and nonlinear intensity distortion). The resulting ventilation-based segmentations were used to assess algorithmic performance and characterize optimization domain differences in terms of measurement bias and precision. RESULTS: Although facilitating computational processing and providing discriminating clinically relevant measures of interest, histogram-based segmentation methods discard important contextual spatial information and are consequently less robust in terms of measurement precision in the presence of common MRI artifacts relative to the image-based convolutional neural network. CONCLUSIONS: Direct optimization within the image domain using convolutional neural networks leverages spatial information, which mitigates problematic issues associated with histogram-based approaches and suggests a preferred future research direction. Further, the entire processing and evaluation framework, including the newly reported deep learning functionality, is available as open source through the well-known Advanced Normalization Tools ecosystem.

Effects of Alzheimer's disease and Lewy body disease on subcortical atrophy.

BACKGROUND AND PURPOSE: Subcortical structures are affected by neurodegeneration in Alzheimer's disease (AD) and Lewy body disease (LBD). Although the co-occurrence of AD and LBD pathologies and their possible interaction have been reported, the effect of AD and LBD on subcortical structures remains unknown. The effects of AD and LBD on subcortical atrophy and their relationship with cognitive dysfunction were investigated. METHODS: The cross-sectional study recruited 42 patients with pure AD related cognitive impairment (ADCI), 30 patients with pure LBD related cognitive impairment (LBCI), 58 patients with mixed ADCI and LBCI, and 29 normal subjects. A general linear model was used to compare subcortical volume and shape amongst the groups, to investigate the independent and interaction effects of ADCI and LBCI on subcortical shape and volume, and to analyze the relationship between subcortical volume and cognitive dysfunction in each group. RESULTS: Alzheimer's disease related cognitive impairment and LBCI were independently associated with subcortical atrophies in the hippocampus and amygdala and in the hippocampus and putamen respectively, but their interaction effect was not significant. Compared to the control group, the pure LBCI group exhibited additional local atrophies in the amygdala, caudate and thalamus. Subcortical atrophies correlated differently with cognitive dysfunction according to the underlying causes of cognitive dysfunction. CONCLUSIONS: The patterns of subcortical atrophies and their correlation with cognitive dysfunction differ according to the underlying AD, LBD or concomitant AD and LBD.

[Association between brain glucose metabolism and cardiac dysfunction in patients with ischemic heart disease undergoing (18)F-FDG PET/CT imaging].

Objective: To evaluate the relationship between the brain glucose metabolism and left ventricular function parameters, and to explore the cerebral glucose metabolism reduction regions in patients with ischemic heart disease (IHD). Methods: A total of 110 consecutive IHD patients who underwent gated (99)Tc(m)-sestamibi (MIBI) SPECT/CT myocardial perfusion imaging, gated (18)F-fluorodeoxyglucose (FDG) PET/CT myocardial and brain glucose metabolic imaging within three days in Beijing Anzhen Hospital from April 2016 to October 2017, were enrolled in this study. Left ventricular functional parameters of SPECT/CT and PET/CT including end-diastolic volume (EDV), end-systolic volume (ESV) and left ventricular ejection fraction (LVEF) were analyzed by QGS software. Viable myocardium and myocardial infarction region were determined by 17-segment and 5 score system, and the ratio of viable myocardium and scar myocardium was calculated. According to the range of viable myocardium, the patients were divided into viable myocardium<10% group (n=44), viable myocardium 10%-<20% group (n=36) and viable myocardium≥20% group (n=30). Pearson correlation analysis was used to analyze the correlation between the range of viable myocardium and scar myocardium and the level of cerebral glucose metabolism. Brain glucose metabolism determined by the mean of standardized uptake value (SUV(mean)) was analyzed by SPM. The ratio of SUV(mean) in whole brain and SUV(mean) in cerebellum were calculated, namely taget/background ratio (TBR). Differences in cerebral glucose metabolism among various groups were analyzed by SPM. Results: There were 101 males, and age was (57±10) years in this cohort. The extent of viable myocardium and the extent of scar, LVEF evaluated by SPECT/CT and PET/CT were significantly correlated with TBR (r=0.280, r=-0.329, r=0.188, r=0.215 respectively,all P<0.05). TBR value was significantly lower in viable myocardium<10% group, compared with viable myocardium 10%-<20% group (1.25±0.97 vs. 1.32±0.17, P<0.05) and viable myocardium≥20% group (1.25±0.97 vs. 1.34±0.16, P<0.05). Furthermore, in comparison with viable myocardium≥20% group, the hypo-metabolic regions of viable myocardium<10% group were located in the precuneus, frontal lobe, postcentral gyrus, parietal lobe, temporal lobe, and so on. Conclusions: There is a correlation between impaired left ventricular function and brain glucose metabolism in IHD patients. In IHD patients with low myocardial viability, the level of glucose metabolism in the whole brain is decreased, especially in the brain functional areas related to cognitive function.

Leukotriene A4 Hydrolase Activation and Leukotriene B4 Production by Eosinophils in Severe Asthma.

Asthma is associated with the overproduction of leukotrienes (LTs), including LTB4. Patients with severe asthma can be highly responsive to 5-lipoxygenase (5-LO) inhibition, which blocks production of both the cysteinyl LTs and LTB4. Production of LTB4 has traditionally been ascribed to neutrophils, mononuclear phagocytes, and epithelial cells, and acts as a chemoattractant for inflammatory cells associated with asthma. The source of LTB4 is unclear, especially in eosinophilic asthma. We speculated that the benefit of 5-LO inhibition could be mediated in part by inhibition of eosinophil-derived LTB4. LTB4 concentrations were assayed in BAL fluid from patients with severe asthma characterized by isolated neutrophilic, eosinophilic, and paucigranulocytic inflammation. Expression of LTA4 hydrolase (LTA4H) by airway eosinophils was determined by immunohistochemistry (IHC). Subsequently, peripheral blood eosinophils were activated and secreted LTB4 was quantified by enzyme immunoassay. Blood eosinophil LTA4H expression was determined by flow cytometry, qPCR, and IHC. LTB4 concentrations were elevated in BAL fluid from patients with severe asthma, including those with isolated eosinophilic inflammation, and these eosinophils displayed LTA4H via IHC. LTA4H expression by blood eosinophils was confirmed by flow cytometry, IHC, and qPCR. Robust LTB4 production by blood eosinophils was observed in response to some, but not all, stimuli. We demonstrated that eosinophils express LTA4H transcripts and protein, and can be stimulated to secrete LTB4. We speculate that in many patients with asthma, eosinophil-derived LTB4 is increased, and this may contribute to the efficacy of 5-LO inhibition.

Suppression of aspirin-mediated eosinophil activation by prostaglandin E2: Relevance to aspirin and nonsteroidal anti-inflammatory drug hypersensitivity.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is characterized by severe, sometimes life-threatening reactions to nonsteroidal anti-inflammatory drugs (NSAIDs). Mechanisms driving the disease include overproduction of leukotrienes and loss of anti-inflammatory prostaglandin E2 (PGE2) production. Many cell types contribute to the disease; however, eosinophils are markedly elevated and are important drivers of pathologic findings. OBJECTIVE: To investigate the capacity of aspirin and NSAIDs to drive eosinophil activation and the ability of PGE2 to inhibit this activation. METHODS: Eosinophils were purified from blood of healthy individuals without AERD and stimulated with lysine aspirin, ketorolac, or sodium salicylate. The role of PGE2 in altering activation was determined by incubating eosinophils with increasing doses of PGE2 before lysine aspirin stimulation. Specific PGE2 receptor use was determined by incubating eosinophils with receptor agonists and antagonists before aspirin stimulation. Cysteinyl leukotrienes (CysLTs), leukotriene B4 (LTB4), and eosinophil-derived neurotoxin (EDN) were quantified by enzyme-linked immunosorbent assay. RESULTS: Stimulation of eosinophils with lysine aspirin, ketorolac, or sodium salicylate resulted in secretion of CysLTs and LTB4 in the absence of EDN release. Low doses of PGE2 inhibited LTB4 and CysLT release, an effect lost at higher PGE2 concentrations. Use of butaprost, an EP2 receptor agonist, suppressed lysine aspirin stimulation. This mechanism was supported by blocking activity of the EP1 and EP3 receptors. CONCLUSION: Eosinophils can be directly activated by NSAIDs via cyclooxygenase-independent pathways to produce CysLTs and LTB4. This effect can be inhibited by PGE2 acting through the EP2 receptor. The recognized loss of EP2 receptor expression combined with low PGE2 levels explains in part the sensitivity to NSAIDs.

Apoptotic cell clearance by bronchial epithelial cells critically influences airway inflammation.

Lung epithelial cells can influence immune responses to airway allergens. Airway epithelial cells also undergo apoptosis after encountering environmental allergens; yet, relatively little is known about how these are cleared, and their effect on airway inflammation. Here we show that airway epithelial cells efficiently engulf apoptotic epithelial cells and secrete anti-inflammatory cytokines, dependent upon intracellular signalling by the small GTPase Rac1. Inducible deletion of Rac1 expression specifically in airway epithelial cells in a mouse model resulted in defective engulfment by epithelial cells and aberrant anti-inflammatory cytokine production. Intranasal priming and challenge of these mice with house dust mite extract or ovalbumin as allergens led to exacerbated inflammation, augmented Th2 cytokines and airway hyper-responsiveness, with decreased interleukin (IL)-10 in bronchial lavages. Rac1-deficient epithelial cells produced much higher IL-33 upon allergen or apoptotic cell encounter, with increased numbers of nuocyte-like cells. Administration of exogenous IL-10 'rescued' the airway inflammation phenotype in Rac1-deficient mice, with decreased IL-33. Collectively, these genetic and functional studies suggest a new role for Rac1-dependent engulfment by airway epithelial cells and in establishing the anti-inflammatory environment, and that defects in cell clearance in the airways could contribute to inflammatory responses towards common allergens.

Effects of lobeglitazone, a novel thiazolidinedione, on adipose tissue remodeling and brown and beige adipose tissue development in db/db mice.

BACKGROUND/OBJECTIVES: We investigated the effect of long-term treatment with lobeglitazone, a novel thiazolidinedione-based activator of peroxisome proliferator-activated receptor gamma, on adipose tissue (AT), focusing on its effects on insulin resistance in obese db/db mice. METHODS: Seven-week-old male db/db mice were assigned to either a vehicle-treated (n=8) or lobeglitazone-treated (n=8) group. Lobeglitazone (1 mg kg-1 daily) was injected intraperitoneally for 20 weeks. RESULTS: Lobeglitazone treatment for 20 weeks resulted in a remarkably improved glycemic index, including significantly decreased glucose levels, enhanced insulin sensitivity and preserved pancreatic beta cells. Both whole body and subcutaneous AT weight increased in the lobeglitazone-treated group. However, lobeglitazone induced an increase in the number of small adipocyte in both epididymal and subcutaneous AT, with a significant weight decrease in the epididymal AT of db/db mice. Using flow cytometry, the CD11c-positive M1 macrophages and CD206-positive M2 macrophages in the epididymal AT were observed to exhibit a decreased M1-to-M2 ratio in lobeglitazone-treated db/db mice. Furthermore, in the lobeglitazone-treated group, interscapular brown AT was clearly visualized by 18F-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) and its mass was significantly greater than that of the vehicle-treated group. In the lobeglitazone-treated group, beige-specific gene expression and the number of mitochondria in white AT were upregulated. Lobeglitazone, with upregulating interferon regulatory factor-4 (a key transcriptional regulator of thermogenesis), promoted the development of brown adipocytes and the differentiation of white adipocytes into beige adipocytes. CONCLUSIONS: Long-term lobeglitazone treatment has a beneficial role in remodeling and ameliorating inflammation in white AT and in glycemic control, in relation to insulin sensitivity in obese db/db mice. Moreover, lobeglitazone induced the differentiation of brown and beige adipocytes. Collectively, our data suggest that lobeglitazone treatment provides promising effects on white and brown AT as well as great improvement in glycemic control, as a potent insulin sensitizer.

Co-clinical trials demonstrate predictive biomarkers for dovitinib, an FGFR inhibitor, in lung squamous cell carcinoma.

BACKGROUND: We conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC). METHODS: The PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected to in vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling. RESULTS: The PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations of FGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18 key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib. CONCLUSIONS: FGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Exogenous administration of DLK1 ameliorates hepatic steatosis and regulates gluconeogenesis via activation of AMPK.

BACKGROUND/OBJECTIVES: Activation of Notch signaling pathologically enhances lipogenesis and gluconeogenesis in the liver causing non-alcoholic fatty liver disease (NAFLD) and diabetes. Delta-like 1 homolog (DLK1), an imprinted gene that can modulate adipogenesis and muscle development in mice, was found as an inhibitory regulator of Notch signaling. Therefore, we investigated the metabolic effect of exogenous DLK1 in vitro and in vivo. SUBJECTS/METHODS: A soluble DLK1 peptide was generated with fusion between a human Fc fragment and extracellular domain of DLK1. Male db/db mice were randomly assigned to two groups: vehicle treated and DLK1-treated group (25 mg kg(-1), intraperitoneal injection, twice a week for 4 weeks). Primary mice hepatocytes and HepG2 cells were used for in vitro experiments. RESULTS: After 4 weeks of DLK1 administration, hepatic triglyceride content and lipid droplets in liver tissues, as well as serum levels of liver enzymes, were markedly decreased in db/db mice. DLK1 treatment induced phosphorylation of AMPK and ACC and suppressed nuclear expression of SREBP-1c in the mouse liver or hepatocytes, indicating regulation of fatty acid oxidation and synthesis pathways. Furthermore, DLK1-treated mice showed significantly lower levels of fasting and random glucose, with improved glucose and insulin tolerance compared with the vehicle-treated group. Macrophage infiltration and proinflammatory cytokine levels in the epididymal fat were decreased in DLK1-treated db/db mice. Moreover, DLK1 suppressed glucose production from hepatocytes, which was blocked after co-administration of an AMPK inhibitor, compound C. DLK1-treated hepatocytes and mouse liver tissues showed lower PEPCK and G6Pase expression. DLK1 triggered AKT phosphorylation followed by cytosolic translocation of FOXO1 from the nucleus in hepatocytes. CONCLUSIONS: The present study demonstrated that exogenous administration of DLK1 reduced hepatic steatosis and hyperglycemia via AMPK activation in the liver. This result suggests that DLK1 may be a novel therapeutic approach for treating NAFLD and diabetes.

Determination of influence of food intake after a single oral dose of mosapride in beagle dogs using nonlinear mixed effect modeling.

The objective of this study was to describe the population pharmacokinetics (PK) of mosapride under fasting and fed conditions. A single 5-mg oral dose of mosapride was administered to fasted (n = 15) and fed (n = 12) beagle dogs. Plasma concentrations of mosapride were subsequently measured by liquid chromatography-tandem mass spectrometry. Data were analyzed using modeling approaches with the NONMEM 7.2 software. A one-compartment open PK model utilizing model event time (MTIME) with first-order absorption and first-order elimination was found to be more appropriate than all other PK models tested. The absorption rate constants of mosapride were significantly decreased under fed conditions, compared to fasting conditions. The observed bootstrap medians of PK parameters were generally consistent with the corresponding population mean estimates. Furthermore, with the exception of some mosapride concentrations, most of observed data fell into the range of the 5th and 95th percentiles of the simulated values. Overall, the final model was able to describe the observed mosapride concentrations reasonably well. These findings suggest that food intake affects both the rate and extent of absorption of mosapride and that the pharmacological effect of mosapride can differ significantly depending on food intake.

Mechanistic model of natural killer cell proliferative response to IL-15 receptor stimulation.

Natural killer (NK) cells are innate lymphocytes that provide early host defense against intracellular pathogens, such as viruses. Although NK cell development, homeostasis, and proliferation are regulated by IL-15, the influence of IL-15 receptor (IL-15R)-mediated signaling at the cellular level has not been quantitatively characterized. We developed a mathematical model to analyze the kinetic interactions that control the formation and localization of IL-15/IL-15R complexes. Our computational results demonstrated that IL-15/IL-15R complexes on the cell surface were a key determinant of the magnitude of the IL-15 proliferative signal and that IL-15R occupancy functioned as an effective surrogate measure of receptor signaling. Ligand binding and receptor internalization modulated IL-15R occupancy. Our work supports the hypothesis that the total number and duration of IL-15/IL-15R complexes on the cell surface crosses a quantitative threshold prior to the initiation of NK cell division. Furthermore, our model predicted that the upregulation of IL-15Rα on NK cells substantially increased IL-15R complex formation and accelerated the expansion of dividing NK cells with the greatest impact at low IL-15 concentrations. Model predictions of the threshold requirement for NK cell recruitment to the cell cycle and the subsequent exponential proliferation correlated well with experimental data. In summary, our modeling analysis provides quantitative insight into the regulation of NK cell proliferation at the receptor level and provides a framework for the development of IL-15 based immunotherapies to modulate NK cell proliferation.