Sphingosine kinase 1-specific inhibitor PF543 reduces goblet cell metaplasia of bronchial epithelium in an acute asthma model

Sphingosine kinase 1 (SPHK1) has been shown to play a key role in the pathogenesis of asthma where SPHK1-generated sphingosine-1-phosphate (S1P) is known to mediate innate and adaptive immunity while promoting mast cell degranulation. Goblet cell metaplasia (GCM) contributes to airway obstruction in asthma and has been demonstrated in animal models. We investigated the role of PF543, a SPHK1-specific inhibitor, in preventing the pathogenesis of GCM using a murine (C57BL/6) model of allergen-induced acute asthma. Treatment with PF543 before triple allergen exposure (DRA: House dust mite, Ragweed pollen, and Aspergillus) reduced inflammation, eosinophilic response, and GCM followed by reduced airway hyperreactivity to intravenous methacholine. Furthermore, DRA exposure was associated with increased expression of SPHK1 in the airway epithelium which was reduced by PF543. DRA-induced reduction of acetylated α-tubulin in airway epithelium was associated with an increased expression of NOTCH2 and SPDEF which was prevented by PF543. In vitro studies using human primary airway epithelial cells showed that inhibition of SPHK1 using PF543 prevented an allergen-induced increase of both NOTCH2 and SPDEF. siRNA silencing of SPHK1 prevented the allergen-induced increase of both NOTCH2 and SPDEF. NOTCH2 silencing was associated with a reduction of SPDEF but not that of SPHK1 upon allergen exposure. Our studies demonstrate that inhibition of SPHK1 protected allergen-challenged airways by preventing GCM and airway hyperreactivity, associated with downregulation of the NOTCH2-SPDEF signaling pathway. This suggests a potential novel link between SPHK1, GCM, and airway remodeling in asthma.NEW & NOTEWORTHY The role of SPHK1-specific inhibitor, PF543, in preventing goblet cell metaplasia (GCM) and airway hyperreactivity (AHR) is established in an allergen-induced mouse model. This protection was associated with the downregulation of NOTCH2-SPDEF signaling pathway, suggesting a novel link between SPHK1, GCM, and AHR.

NOX4 Mediates Epithelial Cell Death in Hyperoxic Acute Lung Injury Through Mitochondrial Reactive Oxygen Species

Management of acute respiratory distress involves O₂ supplementation, which is lifesaving, but causes severe hyperoxic acute lung injury (HALI). NADPH oxidase (NOX) could be a major source of reactive oxygen species (ROS) in hyperoxia (HO). Epithelial cell death is a crucial step in the development of many lung diseases. Alveolar type II (AT2) cells are the metabolically active epithelial cells of alveoli that serve as a source of AT1 cells following lung injury. The aim of this study was to determine the possible role of AT2 epithelial cell NOX4 in epithelial cell death from HALI. Wild type (WT), Nox4^fl/fl (control), and Nox4^−/−Spc-Cre mice were exposed to room air (NO) or 95% O₂ (HO) to investigate the structural and functional changes in the lung. C57BL/6J WT animals subjected to HO showed increased expression of lung NOX4 compared to NO. Significant HALI, increased bronchoalveolar lavage cell counts, increased protein levels, elevated proinflammatory cytokines and increased AT2 cell death seen in hyperoxic Nox4^fl/fl control mice were attenuated in HO-exposed Nox4^−/−Spc-Cre mice. HO-induced expression of NOX4 in MLE cells resulted in increased mitochondrial (mt) superoxide production and cell apoptosis, which was reduced in NOX4 siRNA silenced cells. This study demonstrates a novel role for epithelial cell NOX4 in accelerating lung epithelial cell apoptosis from HALI. Deletion of the Nox4 gene in AT2 cells or silencing NOX4 in lung epithelial cells protected the lungs from severe HALI with reduced apoptosis and decreased mt ROS production in HO. These results suggest NOX4 as a potential target for the treatment of HALI.

The Role of Sphingolipid Signaling in Oxidative Lung Injury and Pathogenesis of Bronchopulmonary Dysplasia

Premature infants are born with developing lungs burdened by surfactant deficiency and a dearth of antioxidant defense systems. Survival rate of such infants has significantly improved due to advances in care involving mechanical ventilation and oxygen supplementation. However, a significant subset of such survivors develops the chronic lung disease, Bronchopulmonary dysplasia (BPD), characterized by enlarged, simplified alveoli and deformed airways. Among a host of factors contributing to the pathogenesis is oxidative damage induced by exposure of the developing lungs to hyperoxia. Recent data indicate that hyperoxia induces aberrant sphingolipid signaling, leading to mitochondrial dysfunction and abnormal reactive oxygen species (ROS) formation (ROS). The role of sphingolipids such as ceramides and sphingosine 1-phosphate (S1P), in the development of BPD emerged in the last decade. Both ceramide and S1P are elevated in tracheal aspirates of premature infants of <32 weeks gestational age developing BPD. This was faithfully reflected in the murine models of hyperoxia and BPD, where there is an increased expression of sphingolipid metabolites both in lung tissue and bronchoalveolar lavage. Treatment of neonatal pups with a sphingosine kinase1 specific inhibitor, PF543, resulted in protection against BPD as neonates, accompanied by improved lung function and reduced airway remodeling as adults. This was accompanied by reduced mitochondrial ROS formation. S1P receptor1 induced by hyperoxia also aggravates BPD, revealing another potential druggable target in this pathway for BPD. In this review we aim to provide a detailed description on the role played by sphingolipid signaling in hyperoxia induced lung injury and BPD.

Hyperoxia-induced S1P1 signaling reduced angiogenesis by suppression of TIE-2 leading to experimental bronchopulmonary dysplasia

INTRODUCTION

We have earlier shown that hyperoxia (HO)-induced sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling contribute to bronchopulmonary dysplasia (BPD). S1P acts through G protein-coupled receptors, S1P₁ through S1P₅. Further, we noted that heterozygous deletion of S1pr1 ameliorated the HO-induced BPD in the murine model. The mechanism by which S1P₁ signaling contributes to HO-induced BPD was explored.

METHODS

S1pr1^+/+ and S1pr1^+/- mice pups were exposed to either room air (RA) or HO (75% oxygen) for 7 days from PN 1-7. Lung injury and alveolar simplification was evaluated. Lung protein expression was determined by Western blotting and immunohistochemistry (IHC). In vitro experiments were performed using human lung microvascular endothelial cells (HLMVECs) with S1P₁ inhibitor, NIBR0213 to interrogate the S1P₁ signaling pathway.

RESULTS

HO increased the expression of S1pr1 gene as well as S1P₁ protein in both neonatal lungs and HLMVECs. The S1pr1^+/- neonatal mice showed significant protection against HO-induced BPD which was accompanied by reduced inflammation markers in the bronchoalveolar lavage fluid. HO-induced reduction in ANG-1, TIE-2, and VEGF was rescued in S1pr1^+/- mouse, accompanied by an improvement in the number of arterioles in the lung. HLMVECs exposed to HO increased the expression of KLF-2 accompanied by reduced expression of TIE-2, which was reversed with S1P₁ inhibition.

CONCLUSION

HO induces S1P₁ followed by reduced expression of angiogenic factors. Reduction of S1P₁ signaling restores ANG-1/ TIE-2 signaling leading to improved angiogenesis and alveolarization thus protecting against HO-induced neonatal lung injury.

Segment-Specific Orientation of the Dorsal and Ventral Roots for Precise Therapeutic Targeting of Human Spinal Cord

OBJECTIVE

To provide precise description of the dorsal and ventral roots orientation along with the main spinal cord anatomical measurements and their segment-specific variations.

PATIENTS AND METHODS

We collected and analyzed the measurements of the spines, spinal cords, and dorsal and ventral roots (C2-L5) of nine adult cadavers (five males and four females).

RESULTS

This study for the first time provides analysis of the dorsal and ventral roots orientation along with spinal cord anatomical measurements and their segment-specific distribution. The results of this study showed less variability in rostral root angles compared with the caudal. Dorsal and ventral rootlets were oriented mostly perpendicular to the spinal cord at the cervical level and had more parallel orientation to the spinal cord at the thoracic and lumbar segments. The number of rootlets per root was greatest at dorsal cervical and lumbar segments. Spinal cord transverse diameter and width of the dorsal columns were largest at cervical segments. The strongest correlation between the spinal cord and vertebrae structures was found between the length of intervertebral foramen to rostral rootlet distance and vertebral bone length.

CONCLUSION

These results demonstrate consistent variation in spinal cord anatomical features across all tested subjects. The results of this study can be used to locate spinal roots and main spinal cord landmarks based on bone marks on computed tomography or X-rays. These results could improve stereotactic surgical procedures and electrode positioning for neuromodulation procedures.

Psychiatric impact of mobile usage on medical student life: Ringxiety, nomophobia, and sleep

Introduction

The usage of mobile phones has seen exponential growth worldwide.^1,2 While college students use mobile applications for educational purposes, the reports of adverse health problems are emerging.^3,4

Objectives

Investigate the impact of mobile usage patterns on the life of medical students and its association with psychiatric effects concerning ringxiety and nomophobia.

Methods

Data was collected from the 300 medical students of Ashwini Rural Medical College of India through a survey for this cross-sectional study. Chi-square (χ2) was used for statistics that revealed association, mobile phone usage patterns, including time spent before sleep, in classrooms or clinics, and frequency of update checks.

Results

A significant association was found between time spent on mobile before sleep and duration of sleep, and mobile usage in classrooms or clinics and psychological effects (p<0.0001). Significant association observed between mobile use in classes or clinics and the frequency of update checks, and the frequency of update checks and psychological effects (p<0.0001). About 78% of participants distracted in self-study due to mobile. Updates checked every 10 minutes by 14.7%, every hourly by 43%, and during breaks by 42.3%. Mobile low network caused anxiety (13.3%) and irritability (67.3%). About 41.7% of students couldn’t abstain from mobile use for a day. Every student used the mobile phone averagely for 24 minutes before they went to sleep.

Conclusions

Our study results highlight the prevalence of ringxiety and nomophobia in medical school students. With the surging dependency on mobile phones and technology, we need to cautiously monitor its adverse effects on psychology and psychiatric conditions.

Introducing nanoscaled surface morphology and percolation barrier network into mesoporous silica coatings

The advantages of surface pattern and mesoporous character of silica thin films were combined, while preserving the interconnected pore system or creating laterally separated porous volumes surrounded by nonpermeable compact zones.

Antibacterial properties of Ag–TiO2 composite sol–gel coatings

This study reveals the connection between the silver-doping method, the resulting nature and amount of the silver dopant together with the structural properties and the long-term antibacterial activity of composite coatings.

Formation of ge nanocrystals in SiO2 by electron beam evaporation

Ge nanocrystals were formed by electron beam evaporation on SiO2 covered Si substrates. The size and distribution of the nanocrystals were studied by atomic force microscopy, scanning electron microscopy and cross-sectional transmission electron microscopy. Dependencies of the nanocrystal size, of the nanocrystal surface coverage, and sheet resistance obtained by van der Pauw method of the Ge layer have been found on the evaporation time. The suggested growth mechanism for the formation of nanocrystals is the Volmer-Weber type. The sheet resistance exhibited a power dependence on the nanocrystal size.

Electrical and memory properties of Si3N4 MIS structures with embedded Si nanocrystals

Memory structures with an embedded sheet of separated Si nanocrystals were prepared by low pressure chemical vapour deposition using a Si3N4 control layer and different Si2O2 or Si3N4 tunnel layers. It was obtained that Si nanocrystals improve the charging behaviour of the MNOS structures. Memory window width of 1.3 V and 2.0 V were obtained for pulse amplitudes of +/-9 V and +/-10 V, 100 ms, respectively. The extrapolated memory window after 10 years is about 15% of its initial value.

Risk factors for doxorubicin-induced congestive heart failure

Potential risk factors responsible for development of doxorubicin-induced congestive heart failure were examined through retrospective analysis of 4018 patient records. The overall incidence of drug-induced congestive heart failure was 2.2% (88 cases). The probability of incurring doxorubicin-induced congestive heart failure was related to the total dose of doxorubicin administered. There was a continuum of increasing risk as the cumulative amount of administered drug increased. A weekly dose schedule of doxorubicin was associated with a significantly lower incidence of congestive heart failure than was the usually employed every 3-week schedule. An increase in drug-related congestive heart failure was also seen with advancing patient age. Performance status, sex, race, and tumor type were not risk factors. These data will enable clinicians to better estimate the risk/benefit ratio in individual patients receiving prolonged administration of doxorubicin. They also provide a basis for the investigation of less cardiotoxic anthracycline analogues or for designing measures to prevent doxorubicin-induced cardiomyopathy.