Medical, Dental, and Nursing Students' Experience with Virtual Practical Sessions: A Cross-Sectional Study in a Developing Country.

Background: The COVID-19 pandemic has disrupted the scope of healthcare education and shifted the teaching methods from on-campus to virtual. The impact of such a shift has rarely been investigated, and limited evidence exists about students' experience in terms of effort made and time spent, especially for laboratory sessions. Assessing students' experiences will provide paramount evidence to fine-tune laboratory virtual learning sessions. Objective: To assess students' experience of virtual (online) laboratory sessions versus on-campus laboratory sessions, including preference, time spent, the effort made, ability to remember instructions, and preference for future teaching. Methods: A cross-sectional study was utilized. A Google Forms questionnaire was prepared and sent to medicine, dentistry, and nursing school students registered at Jordan University of Science and Technology (JUST) during the 2019/2020 academic year. Self-reported preference, time spent, efforts made, ability to remember instructions and preference for future teaching were assessed for virtual versus on-campus anatomy, pathology, microbiology, histology, and physiology laboratory sessions. Results: A total of 455 students participated in this questionnaire. More students in histology (55.2%), pathology (57.4%), and microbiology (55.3%) laboratories, but not anatomy (39.6%) physiology (443.95), reported preferring virtual sessions over on-campus sessions. More students from histology (35.6%) and microbiology (37.0%) reported spending less effort than on-campus sessions. More than half of the participants agreed that virtual laboratory sessions consumed less time than on-campus sessions. Participants reported that they cannot remember the instruction given during virtual teaching compared to on-campus teaching. Differences in students' experiences were detected by gender, major, and year of study. Conclusion: The COVID-19 pandemic has the potential to change the future of healthcare education, and preparation for future crises is paramount. Effort made, time spent, ability to remember, and preference for virtual education should be considered in terms of gender, major of study, and year. These differences should also be reflected in the planning of virtual sessions for effective implementation.

Factors contributing to poor COVID-19 outcomes in diabetic patients: Findings from a single-center cohort study.

Diabetes Mellitus (DM) is a frequent comorbidity in patients infected with the SARS-CoV-2 virus. The risk of developing severe or critical COVID-19 and higher mortality was observed to be increased in diabetic patients hospitalized due to COVID-19. In this study we aimed to find out the impact of clinical characteristics, comorbidities, laboratory results, and complications on the outcomes of diabetic patients hospitalized due to COVID-19. This article is a retrospective cohort study that include diabetic patients hospitalized with COVID-19 infection. A definition of diabetes was based on the past history of diabetes or if the HbA1c was 6.5% or higher. Demographics, clinical characteristics, comorbidities, laboratory results, and complications were extracted from the electronic medical records. The mortality rate increased with increasing age (from 5.56% in younger patients to 46% in the elderly) and with severity (from 25.71% in moderate cases to 43.77% in critical cases). We found that a critical severity on admission (OR: 5.26, 95% CI: 1.28-21.66, p = 0.0214), a history of stroke (OR: 8.37, 95% CI: 2.2-31.88, p = 0.0018), and low calcium levels on admission (OR: 2.23, 95% CI: 1.01-4.91, p = 0.0475) were significant risk factors predicting higher COVID-19 mortality in diabetic patients. The findings of this study suggest that reduced calcium levels could potentially indicate higher mortality due to COVID-19 in patients with DM. Furthermore, careful monitoring of diabetic patients hospitalized due to COVID-19 infection, especially those with critical disease severity or those with a history of stroke, may improve their outcome and lessen mortality.

Acid-base imbalance as a risk factor for mortality among COVID-19 hospitalized patients.

Severe coronavirus disease 2019 (COVID-19) infection can lead to extensive lung infiltrate, a significant increase in the respiratory rate, and respiratory failure, which can affect the acid-base balance. No research in the Middle East has previously examined acid-base imbalance in COVID-19 patients. The present study aimed to describe the acid-base imbalance in hospitalized COVID-19 patients, determine its causes, and assess its impact on mortality in a Jordanian hospital. The study divided patients into 11 groups based on arterial blood gas data. Patients in normal group were defined as having a pH of 7.35-7.45, PaCO2 of 35-45 mmHg, and HCO3- of 21-27 mEq/L. Other patients were divided into 10 additional groups: mixed acidosis and alkalosis, respiratory and metabolic acidosis with or without compensation, and respiratory and metabolic alkalosis with or without compensation. This is the first study to categorize patients in this way. The results showed that acid-base imbalance was a significant risk factor for mortality (P<0.0001). Mixed acidosis nearly quadruples the risk of death when compared with those with normal levels (OR = 3.61, P=0.05). Furthermore, the risk of death was twice as high (OR = 2) for metabolic acidosis with respiratory compensation (P=0.002), respiratory alkalosis with metabolic compensation (P=0.002), or respiratory acidosis with no compensation (P=0.002). In conclusion, acid-base abnormalities, particularly mixed metabolic and respiratory acidosis, were associated with increased mortality in hospitalized COVID-19 patients. Clinicians should be aware of the significance of these abnormalities and address their underlying causes.

Micropatterning of cells via adjusting surface wettability using plasma treatment and graphene oxide deposition.

The wettability of a polymer surface plays a critical role in cell-cell interaction and behavior. The degree to which a surface is hydrophobic or hydrophilic affects the adhesion and behavior of cells. Two distinct techniques for patterning the surface wettability of a Cyclic Olefin Copolymer (COC) substrate were developed and investigated in this article for the purpose of patterning cell growth. These include oxygen plasma treatment and graphene oxide (GO) coating to alter the wettability of the COC substrate and create hydrophilic patterned regions on a hydrophobic surface. When the two techniques are compared, patterning the surface of COC using GO film results in a more stable wettability over time and increases the roughness of the patterned area. Interestingly, both developed techniques were effective at patterning the COC surface's wettability, which modulated cell adhesion and resulted in micropatterning of cell growth. The novel methods described herein can be used in the fields of cell and tissue culture as well as in the development of new biological assays.

Remote E-exams during Covid-19 pandemic: A cross-sectional study of students' preferences and academic dishonesty in faculties of medical sciences.

BACKGROUND: Since the emergence of coronavirus disease 2019 (Covid-19), distance education has been extensively implemented in all educational institutes and remote electronic exams (E-exams) have been adopted as a primary mode of assessment. OBJECTIVES: This cross-sectional study aimed to evaluate the experience of students at faculties of Medicine, Dentistry, Pharmacy, Nursing and Applied Medical Sciences at Jordan University of Science and Technology regarding remote E-exams preferences and academic dishonesty during the pandemic. MATERIALS AND METHODS: The survey composed of 16 questions, prepared using Google forms and distributed through students' E-learning platforms. The survey explored factors affecting students' preference for remote E-exams, methods for course assessment/evaluation, factors related to students' exam dishonesty/misconduct during remote E-exams and measures that can be considered to reduce this behavior. Data were analyzed using descriptive, cross tabulation and Chi-square tests. RESULTS: Among 730 students, approximately only one third preferred remote E-exams. This was significantly (P < 0.05) associated with academic major, efforts/time for remote E-exam preparation, questions appropriateness with study material, and academic achievements (students Grade Point Average (GPA), curriculum objectives). Combining both exams and quizzes was the most preferred method of assessment (30%), while submission of reports or short written assignments were the least preferred ones. Exam dishonesty/misconduct appears as one of the major challenges with remote E-exams. The main measures considered by students to reduce exam dishonesty included substituting the exam with other forms of assessment, using different exam forms, the use of online proctoring solutions and considering compulsory pass/fail grades. CONCLUSION: Results suggested less preference of remote E-exams among students at medical faculties. Findings from this study are highly valuable to plan for academic strategies to overcome difficulties and challenges of remote E-exams. These might include improvement for the distance teaching methodologies, rearrangement of assessment options, modification of the academic curriculum to fit the current situation, and adopting certain measures to prevent exam dishonesty and maintain academic integrity.

Hypertension prevalence and associated factors among patients with diabetes: A retrospective cross-sectional study from Jordan.

BACKGROUND: Hypertension (HTN) is a common comorbidity among diabetic patients. Studies reported that HTN prevalence in patients with diabetes mellitus (DM) depends on many risk factors related to the disease (the type and duration of DM), patients (age, sex, race/ethnicity, BMI), and medical history (glycemic control, renal problems). Best to our knowledge, limited evidence is available in this regard among Jordanian population. OBJECTIVES: This retrospective cross-sectional study aimed to determine the prevalence of HTN among patients with DM in Jordan and factors that might be associated with the concurrence of both diseases. MATERIALS AND METHODS: A cross-sectional study was conducted to determine HTN prevalence and risk factors among diabetic outpatients in Jordan. Patients were asked about their sociodemographic information and medical history. A descriptive analysis was used to determine HTN prevalence and a fit bivariate logistic regression model was used to identify the significant risk factors of HTN in patients with type 2 DM (T2DM). RESULTS: HTN was found to be concurrently occurring in approximately 80% of T2DM patients. This was found to increase with age. In addition, dyslipidemia, gout disease, ischemic heart disease, renal impairment, or a family history of HTN were found to be associated with the concurrence of HTN among T2DM patients. CONCLUSION: Findings from this study highlight the need for proper monitoring of DM patients to reduce the co-occurrence of HTN. Specific attention should be directed to control the patients' glycemic and lipid profiles as well as the cardiac and renal health using non-pharmacological and pharmacological measures. This is of particular importance in T2DM patients at old age and with family history of HTN, to reduce patients' deterioration. Results from this study will also be informative for the development of public health strategies to increase the awareness of the general population regarding T2DM and HTN since both diseases are very common among Jordanian population.

Comparing supervised and semi-supervised Machine Learning Models on Diagnosing Breast Cancer.

BACKGROUND: Breast cancer disease is the most common cancer in US women and the second cause of cancer death among women. OBJECTIVES: To compare and evaluate the performance and accuracy of the key supervised and semi-supervised machine learning algorithms for breast cancer prediction. MATERIALS AND METHODS: We have used nine machine learning classification algorithms for supervised (SL) and semi-supervised learning (SSL): 1) Logistic regression; 2) Gaussian Naive Bayes; 3) Linear Support vector machine; 4) RBF Support vector machine; 5) Decision Tree; 6) Random Forest; 7) Xgboost; 8) Gradient Boosting; 9) KNN. The Wisconsin Diagnosis Cancer dataset was used to train and test these models. To ensure the robustness of the model, we have applied K-fold cross-validation and optimized hyperparameters. We have evaluated and compared the models using accuracy, precision, recall, F1-score, and ROC curves. RESULTS: The results of all models are inspiring using both SL and SSL. The SSL has high accuracy (90%-98%) with just half of the training data. The KNN model for the SL and logistic regression for the SSL achieved the highest accuracy of 98. CONCLUSION: The accuracies of SSL algorithms are very close to the SL algorithms. The accuracies of all models are in the range of 91-98%. SSL is a promising and competitive approach to solve the problem. Using a small sample of labeled and low computational power, the SSL is fully capable of replacing SL algorithms in diagnosing tumor type.

A cross-sectional study to determine factors affecting dental and medical students' preference for virtual learning during the COVID-19 outbreak.

Virtual "online" teaching has been adopted by most universities around the world during the COVID-19 outbreak. This study aims to investigate the factors that might affect students' preference for virtual learning. Since a second wave of such pandemic is expected to occur, professors and teaching assistants may want to be prepared and aware to create an effective virtual learning environment for students. Using an online survey questionnaire, a total of 488 students in their basic science years of study (first to the third year) who are enrolled in dental and medical college responded to the online survey. The authors utilized a binary logistic regression model to estimate the impact of the nine explanatory variables (gender, student's year of study, accessibility of online tools, class engagement in virtual classes, GPA change during COVID-19 outbreak, class attendance in virtual vs. in-person lectures, type of study material, time saving for virtual classes, and anxiety level during the COVID-19 outbreak) on the students' preference for virtual learning. The analysis of variance showed that three out of the nine variables were not significant to the model: gender, study level, and study material. In addition, to understand the behavioral intention for the students during such pandemic, the online survey questionnaire captured students' voice on their willingness to wear masks, wash their hands, or both as well as their acceptance to take the vaccine once it is available. The results showed that 7.02 % of the students did not change simple health behaviors and 18.43% are not interested in taking the vaccine. This implies the importance of enacting new laws for reopening universities, applying high fines for violators, and obligating students to take the vaccine since university settings have high levels of social contact with populations from different communities and countries.

Stress and behavioral changes with remote E-exams during the Covid-19 pandemic: A cross-sectional study among undergraduates of medical sciences.

Emergence of coronavirus disease 2019 (COVID-19) forced the worldwide higher educational institutes to adopt distance learning mode. Further, remote electronic exams (E-exams) were considered as mode of assessment. Objectives: This cross-sectional study evaluated the students' experience of remote E-exams during the COVID-19 pandemic among Medical Sciences students in Jordan. Materials and Methods: A survey of 29 questions was prepared on Google forms and distributed among students at Faculties of Medical Sciences (Medicine, Dentistry, Pharmacy, Nursing and Applied Medical Sciences) at Jordan University of Science and Technology. The questions include students' demographics, stress experience, and factors contributing to stress as well as behavioral changes related to remote E-exams. Responses were analyzed using descriptive, cross tabulation and Chi-square tests. Results: Among 1019 respondents, 32% reported more stress with remote E-exams. This was associated with academic major and gender. Among students with more stress during remote E-exams, the exam duration, mode of questions navigation and technical problems (exam platform and internet connectivity) appeared as the main factors related to stress in 78%, 76% and >60%, respectively. Other factors include concern regarding the teaching methods, exam environment and students' dishonesty. Remote E-exams had negative impact on students' dietary habits (increase consumption of caffeine and high energy drinks, high sugar food, fast food), sleep (reduction in sleeping hours, more consumption of insomnia medications), physical activity (less exercises) and smoking habits (increase). Conclusion: Results suggested a negative impact of E-exams on students within Medical Faculties. Robust exam platform and remote mock E-exams are recommended to reduce students' potential stress. A stress-free environment is very essential to encourage students to adopt remote E-exams, particularly if the pandemic will take longer. Various awareness programs about students' habits related to dietary, sleep quality, physical activity and smoking are highly valuable for students' health benefits. This is of particular importance since the current students at Faculties of Medical Sciences are the future health care providers.

Leukotriene D4 role in allergic asthma pathogenesis from cellular and therapeutic perspectives.

Asthma is a chronic inflammatory and allergic disease that is mainly characterized by reversible airway obstruction and bronchial hyperresponsiveness. The incidence of asthma is increasing with more than 350 million people worldwide are affected. Up to now, there is no therapeutic option for asthma and most of the prescribed drugs aim to ameliorate the symptoms of the disease especially during the acute exacerbations after trigger exposure. Asthma is a heterogonous disease that involves interactions between inflammatory mediators and cellular components within the disease microenvironment including inflammatory and structural cells. Cysteinyl leukotrienes (cys-LTs) are inflammatory lipid mediators that have potent roles in asthma pathogenesis. CysLTs consisting of LTC4, LTD4, and LTE4 are mainly secreted by leukocytes and act through three main G-protein coupled receptors (CysLT1R, CysLT2R, and CysLT3R). LTD4 is the most potent bronchoconstrictor which gives it the priority to be discussed in detail in this review. LTD4 binds with high affinity to CysLT1R and many studies showed that using CysLT1R antagonists such as montelukast has a beneficial effect for asthmatics especially in corticosteroid refractory cases. Since asthma is a heterogeneous inflammatory disease of many cell types involved in the disease pathogenies and LTD4 has a special role in inflammation and bronchoconstriction, this review highlights the role of LTD4 on each cellular component in asthma and the benefits of using CysLT1R antagonists in ameliorating LTD4-induced effects.

Sirtuin 6 and metabolic genes interplay in Warburg effect in cancers.

Under oxygen availability, normal cells undergo mitochondrial oxidative phosphorylation to metabolize glucose and yield up to 36 ATPs per glucose molecule for cellular functions, and undergo non-oxidative metabolism (glycolysis) under hypoxic and proliferating conditions to yield 2 ATP per glucose. These cells metabolize glucose to pyruvate via glycolysis followed by conversion of pyruvate to lactate via lactate dehydrogenase. However, cancer cells have the ability to undergo glycolysis and ferment glucose to lactate regardless of oxygen availability; a phenomenon first addressed by Otto Warburg and called, "Warburg effect". Numerous glycolytic genes/proteins have been identified in tumors; that include glucose transporter 1 (GLUT1), hexokinase 2 (HK2), pyruvate kinase-M2 splice isoform (PKM2), and lactate dehydrogenase (LDH-A). Histone deacetylase sirtuin 6 (SIRT6), an epigenetic regulator, is highly expressed in various cancers. SIRT6 plays an important role in Warburg effect by regulating many glycolytic genes. Loss of SIRT6 enhances tumor growth via enhancing glycolysis. This review is mainly concerned with exploring the most recent advances in understanding the roles of the metabolic genes (GLUT1, HK2, PKM2, and LDH-A) and the epigenetic regulator SIRT6 in cancer metabolism and how SIRT6 can modulate these metabolic genes expression and its possible use as a therapeutic target for cancer treatment.

Transient Receptor Potential Vanilloid channel regulates fibroblast differentiation and airway remodeling by modulating redox signals through NADPH Oxidase 4.

Asthma is characterized by pathological airway remodeling resulting from persistent myofibroblast activation. Although transforming growth factor beta 1 (TGFß1), mechanical signals, and reactive oxygen species (ROS) are implicated in fibroblast differentiation, their integration is still elusive. We identified that Transient Receptor Potential Vanilloid 4 (TRPV4), a mechanosensitive ion channel mediates lung fibroblast (LF) differentiation and D. farinae-induced airway remodeling via a novel TRPV4-NADPH Oxidase 4 (NOX4) interaction. NOX4-mediated ROS production is essential for TGFß1-induced LF differentiation via myocardin-related transcription factor-A (MRTF-A) and plasminogen activator inhibitor 1 (PAI-1). Importantly, TRPV4 inhibition prevented TGFß1-induced NOX4 expression and ROS production. Both TRPV4 and NOX4 are activated by phosphatidylinositol 3-kinase (PI3K) downstream of TGFß1, and signals from both TRPV4 and Rac are necessary for NOX4 upregulation. Notably, NOX4 expression is higher in fibroblasts derived from asthmatic patients (disease human LF; DHLF) in comparison to non-asthmatics (normal human LF; NHLF). Further, NOX4 expression is up-regulated in the lungs of D.farinae-treated wild type mice (WT) relative to saline-treated WT, which was attenuated in TRPV4 knockout (KO) mice. Our findings suggest that TRPV4 integrates TGFß1 and ROS signaling through NOX4 and, TRPV4-NOX4 interaction is amenable to target lung remodeling during asthma.

The effect of dielectrophoresis on living cells: crossover frequencies and deregulation in gene expression.

This article documents the effect of dielectrophoresis on living cells. Given the longer duration procedures performed on microfluidic platforms, the influence of electric fields of high intensity may be of interest in manipulations other than dielectrophoresis. The crossover frequencies of several cell lines were experimentally determined using a microfluidic device. The crossover frequencies are investigated at different medium conductivities for red blood cells, white blood cells-Jurkat, 92.1 and OCM melanoma, and MDA-MB-231 breast cancer cell lines. The effect of dielectrophoresis on the cells at the gene level was also investigated by studying the alteration in gene expressions using microarray analysis. The alterations in genes due to the manipulation of cells at 10 kHz and 100 kHz with a sinusoidal 10 V peak signal for 60 minutes are explored. The two frequencies correspond to negative and positive dielectrophoresis, respectively. The cell line MDA-MB-231 is used as a model for studying the genes in this work. The dielectrophoresis was found to alter genes related to apoptosis, rRNA transcription, cellular respiration, energy production, cellular transcriptional activity, and other cellular functions.

Mechanosensitive transient receptor potential vanilloid 4 regulates Dermatophagoides farinae-induced airway remodeling via 2 distinct pathways modulating matrix synthesis and degradation.

Contributions of mechanical signals to airway remodeling during asthma are poorly understood. Transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel, has been implicated in cardiac and pulmonary fibrosis; however, its role in asthma remains elusive. Employing a Dermatophagoides farinae-induced asthma model, we report here that TRPV4-knockout mice were protected from D. farinae-induced airway remodeling. Furthermore, lung fibroblasts that were isolated from TRPV4-knockout mice showed diminished differentiation potential compared with wild-type mice. Fibroblasts from asthmatic lung exhibited increased TRPV4 activity and enhanced differentiation potential compared with normal human lung fibroblasts. Of interest, TGF-ß1 treatment enhanced TRPV4 activation in a PI3K-dependent manner in normal human lung fibroblasts in vitro Mechanistically, TRPV4 modulated matrix remodeling in the lung via 2 distinct but dependent pathways: one enhances matrix deposition by fibrotic gene activation, whereas the other slows down matrix degradation by increased plasminogen activator inhibitor 1. Of importance, both pathways are regulated by Rho/myocardin-related transcription factor-A and contribute to fibroblast differentiation and matrix remodeling in the lung. Thus, our results support a unique role for TRPV4 in D. farinae-induced airway remodeling and warrant further studies in humans for it to be used as a novel therapeutic target in the treatment of asthma.-Gombedza, F., Kondeti, V., Al-Azzam, N., Koppes, S., Duah, E., Patil, P., Hexter, M., Phillips, D., Thodeti, C. K., Paruchuri, S. Mechanosensitive transient receptor potential vanilloid 4 regulates Dermatophagoides farinae-induced airway remodeling via 2 distinct pathways modulating matrix synthesis and degradation.

Leukotriene D4 and prostaglandin E2 signals synergize and potentiate vascular inflammation in a mast cell-dependent manner through cysteinyl leukotriene receptor 1 and E-prostanoid receptor 3.

BACKGROUND: Although arachidonic acid metabolites, cysteinyl leukotrienes (cys-LTs; leukotriene [LT] C4, LTD4, and LTE4), and prostaglandin (PG) E2 are generated at the site of inflammation, it is not known whether crosstalk exists between these 2 classes of inflammatory mediators. OBJECTIVE: We sought to determine the role of LTD4-PGE2 crosstalk in inducing vascular inflammation in vivo, identify effector cells, and ascertain specific receptors and pathways involved in vitro. METHODS: Vascular (ear) inflammation was assessed by injecting agonists into mouse ears, followed by measuring ear thickness and histology, calcium influx with Fura-2, phosphorylation and expression of signaling molecules by means of immunoblotting, PGD2 and macrophage inflammatory protein 1ß generation by using ELISA, and expression of transcripts by using RT-PCR. Candidate receptors and signaling molecules were identified by using antagonists and inhibitors and confirmed by using small interfering RNA. RESULTS: LTD4 plus PGE2 potentiated vascular permeability and edema, gearing the system toward proinflammation in wild-type mice but not in Kit(W-sh) mice. Furthermore, LTD4 plus PGE2, through cysteinyl leukotriene receptor 1 (CysLT1R) and E-prostanoid receptor (EP) 3, enhanced extracellular signal-regulated kinase (Erk) and c-fos phosphorylation, inflammatory gene expression, macrophage inflammatory protein 1ß secretion, COX-2 upregulation, and PGD2 generation in mast cells. Additionally, we uncovered that this synergism is mediated through Gi, protein kinase G, and Erk signaling. LTD4 plus PGE2-potentiated effects are partially sensitive to CysLT1R or EP3 antagonists but completely abolished by simultaneous treatment both in vitro and in vivo. CONCLUSIONS: Our results unravel a unique LTD4-PGE2 interaction affecting mast cells through CysLT1R and EP3 involving Gi, protein kinase G, and Erk and contributing to vascular inflammation in vivo. Furthermore, current results also suggest an advantage of targeting both CysLT1R and EP3 in attenuating inflammation.

Modulation of mast cell proliferative and inflammatory responses by leukotriene d4 and stem cell factor signaling interactions.

Mast cells (MCs) are important effector cells in asthma and pulmonary inflammation, and their proliferation and maturation is maintained by stem cell factor (SCF) via its receptor, c-Kit. Cysteinyl leukotrienes (cys-LTs) are potent inflammatory mediators that signal through CysLT1 R and CysLT2 R located on the MC surface, and they enhance MC inflammatory responses. However, it is not known if SCF and cys-LTs cross-talk and influence MC hyperplasia and activation in inflammation. Here, we report the concerted effort of the growth factor SCF and the inflammatory mediator LTD4 in MC activation. Stimulation of MCs by LTD4 in the presence of SCF enhances c-Kit-mediated proliferative responses. Similarly, SCF synergistically enhances LTD4 -induced calcium, c-fos expression and phosphorylation, as well as MIP1ß generation in MCs. These findings suggest that integration of SCF and LTD4 signals may contribute to MC hyperplasia and hyper-reactivity during airway hyper-response and inflammation.

Cysteinyl leukotrienes regulate endothelial cell inflammatory and proliferative signals through CysLT2 and CysLT1 receptors.

Cysteinyl leukotrienes (cys-LTs), LTC4, LTD4, LTE4 are potent inflammatory lipid mediators that act through two distinct G-protein-coupled receptors, CysLT1R and CysLT2R. Although cys-LTs are shown to induce vascular leakage and atherosclerosis, the molecular mechanism by which cys-LTs modulate endothelial function is not known. Here, we show that cys-LTs (LTC4 and LTD4) induce robust calcium influx in human umbilical vein endothelial cells (HUVECs) through CysLT2R, but not CysLT1R. Further, cys-LT treatment induced endothelial cell (EC) contraction leading to monolayer disruption via CysLT2R/Rho kinase dependent pathway. Furthermore, stimulation with cys-LTs potentiated TNFα-induced VCAM-1 expression and leukocyte recruitment to ECs through CysLT2R. In contrast, we found that both LTC4 and LTD4 stimulated EC proliferation through CysLT1R. Taken together, these results suggest that cys-LTs induce endothelial inflammation and proliferation via CysLT2R/Rho kinase and CysLT1R/Erk dependent pathways, respectively, which play critical role in the etiology of cardiovascular diseases such as atherosclerosis and myocardial infarction.

Differential regulation of cysteinyl leukotriene receptor signaling by protein kinase C in human mast cells.

Cysteinyl leukotrienes (cys-LTs) are a group of lipid mediators that are potent bronchoconstrictors, powerful inducers of vascular leakage and potentiators of airway hyperresponsiveness. Cys-LTs play an essential role in asthma and are synthesized as well as activated in mast cells (MCs). Cys-LTs relay their effects mainly through two known GPCRs, CysLT1R and CysLT2R. Although protein kinase C (PKC) isoforms are implicated in the regulation of CysLT1R function, neither the role of PKCs in cys-LT-dependent MC inflammatory signaling nor the involvement of specific isoforms in MC function are known. Here, we show that PKC inhibition augmented LTD4 and LTE4-induced calcium influx through CysLT1R in MCs. In contrast, inhibition of PKCs suppressed c-fos expression as well MIP1ß generation by cys-LTs. Interestingly, cys-LTs activated both PKCα and PKCε isoforms in MC. However, knockdown of PKCα augmented cys-LT mediated calcium flux, while knockdown of PKCε attenuated cys-LT induced c-fos expression and MIP1ß generation. Taken together, these results demonstrate for the first time that cys-LT signaling downstream of CysLT1R in MCs is differentially regulated by two distinct PKCs which modulate inflammatory signals that have significant pathobiologic implications in allergic reactions and asthma pathology.