You are What You Drink? How Associations Between Profiles of Beverage Consumption and Type 2 Diabetes Risk are Mediated by Biomarker Networks.

BACKGROUND: Multiple studies have independently investigated the associations of the consumption of individual beverage types and specific plasma biomarkers with the risk of type 2 diabetes (T2D). However, as individuals do not consume single beverage types exclusively and plasma biomarkers do not act in isolation, it remains unclear how patterns of beverage consumption and plasma biomarker networks associate both with each other and T2D risk. OBJECTIVES: We aimed to elucidate potential dietary determinants of T2D risk by defining a model that describes habitual beverage consumption profiles in relation to identified networks of circulating plasma biomarkers. METHODS: This study included 1,461 case and 1,568 control participants from case-control studies of T2D nested within the Nurses' Health Study. Participants completed validated semiquantitative food frequency questionnaires that assessed habitual beverage consumption, and they provided blood samples from which 27 plasma biomarkers of cardiometabolic risk were identified. Common exploratory factor analysis (EFA) identified factors that separately described beverage consumption profiles and biomarker networks. Multivariable-adjusted regression elucidated the relationships between beverage and biomarker factors and T2D risk. RESULTS: EFA revealed five factors describing unique beverage consumption profiles and seven factors describing biomarker networks. The factor describing alcoholic beverage consumption was associated with a reduced risk of T2D (odds ratio [OR]: 0.50 [0.40, 0.64], P<0.001) mediated, in part, by the factor describing increased concentrations of adiponectin biomarkers (19.9% [12.0, 31.1] P = 0.004). The factor describing low-calorie sweetened beverage (LCSBs) consumption was associated with an increased risk of T2D (OR: 1.33 [1.03, 1.72], P = 0.021), and the factor describing lower concentrations of insulin-like growth factor binding proteins 1 and 2, and soluble leptin receptor, and increased leptin concentrations (P = 0.005). CONCLUSIONS: Moderate alcohol consumption was associated with reduced T2D risk, mediated in part by increased circulating adiponectin. LCSB consumption was associated with both increased T2D risk and perturbed insulin-like growth factor and leptin signaling.

Migration of retained tarsal bee stinger onto the ocular surface causing superficial keratopathy.

We report a case of keratopathy due to retained stinger elements following a bee sting and envenomation of the ocular adnexa. A 48-year-old woman presented with a 2-day history of right-sided eye pain, photophobia, and reduced visual acuity. Six days prior to presentation, she had been stung on the right upper eyelid by a bee. Her usual practitioner had removed the stinger and commenced a course of oral antibiotics. Anterior segment examination revealed coarse linear abrasions and superficial punctate keratitis with associated epithelial edema. Eversion of the right upper eyelid revealed the presence of retained stinger lancets near the medial eyelid margin. The retained stinger was removed, and the patient responded well to treatment with topical antibiotics, steroids, and cycloplegia.

Risk of Mental Health Problems in Children and Youths Following Concussion.

IMPORTANCE: Concussion may exacerbate existing mental health issues. Little evidence exists on whether concussion is associated with the onset of new psychopathologies or long-term mental health problems. OBJECTIVE: To investigate associations between concussion and risk of subsequent mental health issues, psychiatric hospitalizations, self-harm, or suicides. DESIGN, SETTING, AND PARTICIPANTS: This population-based retrospective cohort study including children and youths aged 5 to 18 years with a concussion or orthopedic injury incurred between April 1, 2010, and March 31, 2020, in Ontario, Canada. Participants had no previous mental health visit in the year before the index event for cohort entry and no prior concussion or traumatic brain injury 5 years before the index visit. Data were collected from provincewide health administrative databases. Participants with concussion were included in the exposed cohort, and those with an orthopedic injury were included in the comparison cohort; these groups were matched 1:2, respectively, on age and sex. EXPOSURES: Concussion or orthopedic injury. MAIN OUTCOMES AND MEASURES: The primary outcome was mental health problems, such as psychopathologies and psychiatric disorders, identified from health care visits in emergency departments, hospitalizations, or primary care settings. Secondary outcomes were psychiatric hospitalizations, self-harm health care visits, and death by suicide (identified in health care or vital statistics databases). RESULTS: A total of 152 321 children and youths with concussion (median [IQR] age, 13 [10-16] years; 86 423 [56.7%] male) and 296 482 children and youths with orthopedic injury (median [IQR] age, 13 [10-16] years; 171 563 [57.9%] male) were matched by age and sex. The incidence rates of any mental health problem were 11 141 per 100 000 person-years (exposed group) and 7960 per 100 000 person-years (unexposed group); with a difference of 3181 (95% CI, 3073-3291) per 100 000 person-years. The exposed group had an increased risk of developing a mental health issue (adjusted hazard ratio [aHR], 1.39; 95% CI, 1.37-1.40), self-harm (aHR, 1.49; 95% CI, 1.42-1.56), and psychiatric hospitalization (aHR, 1.47; 95% CI, 1.41-1.53) after a concussion. There was no statistically significant difference in death by suicide between exposed and unexposed groups (HR, 1.54; 95% CI, 0.90-2.61). CONCLUSIONS AND RELEVANCE: Among children and youths aged 5 to 18 years, concussion was associated with an increased risk of mental health issues, psychiatric hospitalization, and self-harm compared with children and youths with an orthopedic injury.

Quinine Effects on Gut and Pancreatic Hormones and Antropyloroduodenal Pressures in Humans-Role of Delivery Site and Sex.

CONTEXT: The bitter substance quinine modulates the release of a number of gut and gluco-regulatory hormones and upper gut motility. As the density of bitter receptors may be higher in the duodenum than the stomach, direct delivery to the duodenum may be more potent in stimulating these functions. The gastrointestinal responses to bitter compounds may also be modified by sex. BACKGROUND: We have characterized the effects of intragastric (IG) versus intraduodenal (ID) administration of quinine hydrochloride (QHCl) on gut and pancreatic hormones and antropyloroduodenal pressures in healthy men and women. METHODS: 14 men (26 ±â€…2 years, BMI: 22.2 ±â€…0.5 kg/m2) and 14 women (28 ±â€…2 years, BMI: 22.5 ±â€…0.5 kg/m2) received 600 mg QHCl on 2 separate occasions, IG or ID as a 10-mL bolus, in randomized, double-blind fashion. Plasma ghrelin, cholecystokinin, peptide YY, glucagon-like peptide-1 (GLP-1), insulin, glucagon, and glucose concentrations and antropyloroduodenal pressures were measured at baseline and for 120 minutes following QHCl. RESULTS: Suppression of ghrelin (P = 0.006), stimulation of cholecystokinin (P = 0.030), peptide YY (P = 0.017), GLP-1 (P = 0.034), insulin (P = 0.024), glucagon (P = 0.030), and pyloric pressures (P = 0.050), and lowering of glucose (P = 0.001) were greater after ID-QHCl than IG-QHCl. Insulin stimulation (P = 0.021) and glucose reduction (P = 0.001) were greater in females than males, while no sex-associated effects were found for cholecystokinin, peptide YY, GLP-1, glucagon, or pyloric pressures. CONCLUSION: ID quinine has greater effects on plasma gut and pancreatic hormones and pyloric pressures than IG quinine in healthy subjects, consistent with the concept that stimulation of small intestinal bitter receptors is critical to these responses. Both insulin stimulation and glucose lowering were sex-dependent.

Incidence of chronic immune-mediated inflammatory diseases after diagnosis with Kawasaki disease: a population-based cohort study.

OBJECTIVES: Kawasaki disease (KD) is an immune-mediated vasculitis of childhood with multi-organ inflammation. We determined the risk of subsequent immune-mediated inflammatory disease (IMID), including arthritis, type 1 diabetes, IBD, autoimmune liver disease, primary sclerosing cholangitis and multiple sclerosis. METHODS: We conducted a matched population-based cohort study using health administrative data from Ontario, Canada. Children aged <18 years born between 1991 and 2016 diagnosed with KD (n = 3753) were matched to 5 non-KD controls from the general population (n = 18 749). We determined the incidence of IMIDs after resolution of KD. Three- and 12-month washout periods were used to exclude KD-related symptoms. RESULTS: There was an elevated risk of arthritis in KD patients compared with non-KD controls, starting 3 months after index date [103.0 vs 12.7 per 100 000 person-years (PYs); incidence rate ratio 8.07 (95% CI 4.95, 13.2); hazard ratio 8.08 (95% CI 4.95, 13.2), resulting in the overall incidence of IMIDs being elevated in KD patients (175.1 vs 68.0 per 100 000 PYs; incidence rate ratio 2.58 (95% CI 1.93, 3.43); hazard ratio 2.58, 95% CI 1.94, 3.43]. However, there was no increased risk for diabetes, IBD, autoimmune liver disease, primary sclerosing cholangitis or multiple sclerosis in KD patients. Similar results were observed using a 12-month washout period. CONCLUSION: Children diagnosed with KD were at increased risk of arthritis following the acute KD event, but not other IMIDs. Health-care providers should monitor for arthritis in children following a diagnosis of KD.

The impact of COVID-19 on community antibiotic use in Canada: an ecological study.

OBJECTIVES: The COVID-19 pandemic has had an effect on the incidence of infectious diseases and medical care. This study aimed to describe the impact of the COVID-19 pandemic on community-level antibiotic use. METHODS: Using national antibiotic dispensing data from IQVIA's CompuScript database, this ecological study investigated antibiotic dispensing through community retail pharmacies in Canada from November 2014 to October 2020. Analyses were stratified by age, sex, prescription origin and approximate indication. RESULTS: Adjusting for seasonality, the national rate of antibiotic dispensing in Canada decreased by 26.5% (50.4 to 37.0 average prescriptions per 1000 inhabitants) during the first 8 months of the Canadian COVID-19 period (March to October 2020), compared with the pre-COVID-19 period. Prescribing rates in children ≤18 years decreased from 43.7 to 12.2 prescriptions per 1000 inhabitants in males (-72%) and from 46.8 to 14.9 prescriptions per 1000 inhabitants in females (-68%) in April 2020. Rates in adults ≥65 decreased from 74.9 to 48.8 prescriptions per 1000 inhabitants in males (-35%) and from 91.7 to 61.3 prescriptions per 1000 inhabitants in females (-33%) in May 2020. Antibiotic prescriptions from family physicians experienced a greater decrease than from surgeons and infectious disease physicians. Prescribing rates for antibiotics for respiratory indications decreased by 56% in May 2020 (29.2 to 12.8 prescriptions per 1000 inhabitants), compared with prescribing rates for urinary tract infections (9.4 to 7.8 prescriptions per 1000 inhabitants; -17%) and skin and soft tissue infections (6.4 to 5.2 prescriptions per 1000 inhabitants; -19%). DISCUSSION: The first 8 months of the COVID-19 pandemic reduced community antibiotic dispensing by 26.5% in Canada, compared with the marginal decrease of 3% in antibiotic consumption between 2015 and 2019. Further research is needed to understand the implications and long-term effects of the observed reductions on antibiotic use on antibiotic resistance in Canada.

Health care costs of hospitalization of young children for respiratory syncytial virus infections: a population-based matched cohort study.

BACKGROUND: Respiratory syncytial virus (RSV) infection poses a substantial clinical burden among infants and young children. We sought to determine the health care costs of hospitalizations attributable to RSV in Ontario, Canada, from the health care payer perspective. METHODS: For this population-based matched cohort study, we identified children younger than 24 months who were or were not hospitalized with RSV infections in 2006-2016. We performed a cost-of-illness analysis using linked administrative health data, with subjects stratified by gestational age and congenital heart disease, and propensity score-matched on established risk factors. The primary outcome was attributable health care costs per patient, reflecting the difference in direct medical costs between the groups, calculated to 12 months postdischarge in 2020 Canadian dollars. RESULTS: We identified 14 608 RSV-infected children, matched to 72 040 controls. The adjusted attributable cost of hospitalized RSV was $134 931 900 over 10 years, or $9240 per patient (95% confidence interval [CI] $8790-$9690). Health care costs escalated 3 days before hospitalization, and persisted up to 12 months after discharge. Increased costs were associated with major comorbidities, but not extreme premature birth. The highest mean attributable cost per patient was in the presence of hemodynamically significant heart disease ($60 110, 95% CI $26 700-$93 060). Infants born at 36-43 weeks' gestation constituted the greatest overall cost burden at $117 886 720. INTERPRETATION: Although the greatest direct medical costs per patient hospitalized with RSV infection are among children with cardiac disease, the greatest overall cost burden is from children born at or near term, who are not targeted by current prophylaxis strategies. The substantial attributable health care costs of RSV can inform cost-effectiveness analyses of novel RSV vaccines and prioritization of health care resources.

Comparative Effects of Intragastric and Intraduodenal Administration of Quinine on the Plasma Glucose Response to a Mixed-Nutrient Drink in Healthy Men: Relations with Glucoregulatory Hormones and Gastric Emptying.

BACKGROUND: In preclinical studies, bitter compounds, including quinine, stimulate secretion of glucoregulatory hormones [e.g., glucagon-like peptide-1 (GLP-1)] and slow gastric emptying, both key determinants of postprandial glycemia. A greater density of bitter-taste receptors has been reported in the duodenum than the stomach. Thus, intraduodenal (ID) delivery may be more effective in stimulating GI functions to lower postprandial glucose. OBJECTIVE: We compared effects of intragastric (IG) and ID quinine [as quinine hydrochloride (QHCl)] administration on the plasma glucose response to a mixed-nutrient drink and relations with gastric emptying, plasma C-peptide (reflecting insulin secretion), and GLP-1. METHODS: Fourteen healthy men [mean ± SD age: 25 ± 3 y; BMI (in kg/m2): 22.5 ± 0.5] received, on 4 separate occasions, in double-blind, randomly assigned order, 600 mg QHCl or control, IG or ID, 60 min (IG conditions) or 30 min (IG conditions) before a mixed-nutrient drink. Plasma glucose (primary outcome) and hormones were measured before, and for 2 h following, the drink. Gastric emptying of the drink was measured using a 13C-acetate breath test. Data were analyzed using repeated-measures 2-way ANOVAs (factors: treatment and route of administration) to evaluate effects of QHCl alone and 3-way ANOVAs (factors: treatment, route-of-administration, and time) for responses to the drink. RESULTS: After QHCl alone, there were effects of treatment, but not route of administration, on C-peptide, GLP-1, and glucose (P < 0.05); QHCl stimulated C-peptide and GLP-1 and lowered glucose concentrations (IG control: 4.5 ± 0.1; IG-QHCl: 3.9 ± 0.1; ID-control: 4.6 ± 0.1; ID-QHCl: 4.2 ± 0.1 mmol/L) compared with control. Postdrink, there were treatment × time interactions for glucose, C-peptide, and gastric emptying, and a treatment effect for GLP-1 (all P < 0.05), but no route-of-administration effects. QHCl stimulated C-peptide and GLP-1, slowed gastric emptying, and reduced glucose (IG control: 7.2 ± 0.3; IG-QHCl: 6.2 ± 0.3; ID-control: 7.2 ± 0.3; ID-QHCl: 6.4 ± 0.4 mmol/L)  compared with control. CONCLUSIONS: In healthy men, IG and ID quinine administration similarly lowered plasma glucose, increased plasma insulin and GLP-1, and slowed gastric emptying. These findings have potential implications for lowering blood glucose in type 2 diabetes. This study was registered as a clinical trial with the Australian New Zealand Clinical Trials at www.anzctr.org.au as ACTRN12619001269123.

IOData: A python library for reading, writing, and converting computational chemistry file formats and generating input files.

IOData is a free and open-source Python library for parsing, storing, and converting various file formats commonly used by quantum chemistry, molecular dynamics, and plane-wave density-functional-theory software programs. In addition, IOData supports a flexible framework for generating input files for various software packages. While designed and released for stand-alone use, its original purpose was to facilitate the interoperability of various modules in the HORTON and ChemTools software packages with external (third-party) molecular quantum chemistry and solid-state density-functional-theory packages. IOData is designed to be easy to use, maintain, and extend; this is why we wrote IOData in Python and adopted many principles of modern software development, including comprehensive documentation, extensive testing, continuous integration/delivery protocols, and package management. This article is the official release note of the IOData library.

Predictors of Hospitalization for Children With Croup, a Population-Based Cohort Study.

OBJECTIVES: We sought to determine predictors of hospitalization for children presenting with croup to emergency departments (EDs), as well as predictors of repeat ED presentation and of hospital readmissions within 18 months of index admission. We also aimed to develop a practical tool to predict hospitalization risk upon ED presentation. METHODS: Multiple deterministically linked health administrative data sets from Ontario, Canada, were used to conduct this population-based cohort study between April 1, 2006 and March 31, 2017. Children born between April 1, 2006, and March 31, 2011, were eligible if they had 1 ED visit with a croup diagnosis. Multivariable logistic regression was used to determine factors associated with hospitalization, subsequent ED visits, and subsequent croup hospitalizations. A multivariable prediction tool and associated scoring system were created to predict hospitalization risk within 7 days of ED presentation. RESULTS: Overall, 1811 (3.3%) of the 54 981 eligible children who presented to an Ontario ED were hospitalized. Significant hospitalization predictors included age, sex, Canadian Triage and Acuity Scale score, gestational age at birth, and newborn distress. Younger patients and boys were more likely to revisit the ED for croup. Our multivariable prediction tool could forecast hospitalization up to a 32% probability for a given patient. CONCLUSIONS: This study is the first population-based study in which predictors of hospitalization for croup based on demographic and historical factors are identified. Our prediction tool emphasized the importance of symptom severity on ED presentation but will require refinement before clinical implementation.

A Simple Method for Including Polarization Effects in Solvation Free Energy Calculations When Using Fixed-Charge Force Fields: Alchemically Polarized Charges.

The incorporation of polarizability in classical force-field molecular simulations is an ongoing area of research. We focus here on its application to hydration free energy simulations of organic molecules. In contrast to computationally complex approaches involving the development of explicitly polarizable force fields, we present herein a simple methodology for incorporating polarization into such simulations using standard fixed-charge force fields, which we call the alchemically polarized charges (APolQ) method. APolQ employs a standard classical alchemical free energy change simulation to calculate the free energy difference between a fully polarized solute particle in a condensed phase and its unpolarized state in a vacuum. APolQ can in principle be applied to any microscopically homogeneous system (e.g., pure or mixed solvents). We applied APolQ to hydration free energy data for a test set of 45 neutral solute molecules in the FreeSolv database and compared results obtained using three different water models (SPC/E, TIP3P, and OPC3) and using minimal basis iterative Stockholder (MBIS) and restrained electrostatic potential (RESP) partial charge methodologies. In comparison with AM1-BCC, we found that APolQ outperforms it for the test set. Despite our method using default GAFF parameters, the MBIS partial charges yield absolute average deviations 1.5-1.9 kJ mol-1 lower than using AM1 bond charge correction (AM1-BCC). We conjecture that this method can be further improved by fitting the Lennard-Jones and torsional parameters to partial charges derived using MBIS or RESP methodologies.

The Characteristics and Effectiveness of Interventions for Frequent Emergency Department Utilizing Patients With Chronic Noncancer Pain: A Systematic Review.

BACKGROUND: Patients with chronic noncancer pain (CNCP) present unique challenges to emergency department (ED) care providers and administrators. Their conditions lead to frequent ED visits for pain relief and symptom management and are often poorly addressed with costly, low-yield care. A systematic review has not been performed to inform the management of frequent ED utilizing patients with CNCP. Therefore, we synthesized the available evidence on interventional strategies to improve care-associated outcomes for this patient group. METHODS: We searched Medline, EMBASE, CINAHL, CENTRAL, SCOPUS, and Web of Science from database inception to June 2018 for eligible interventional studies aimed at reducing frequent ED utilization among adult patients with CNCP. Articles were assessed in duplicate in accordance with methodologic recommendations from the Cochrane Handbook for Systematic Reviews of Interventions. Outcomes of interest were the frequency of subsequent ED visits, type and amount of opioids administered in the ED and prescribed at discharge, and costs. Methodologic quality was assessed using the Cochrane Risk of Bias in Non-Randomized Studies of Interventions and Risk of Bias tools for nonrandomized and randomized studies, respectively. RESULTS: Thirteen studies including 1,679 patients met the inclusion criteria. Identified interventions implemented pain policies (n = 4), individualized care plans (n = 5), ED care coordination (n = 2), chronic pain management pathways (n = 1), and behavioral health interventions (n = 1). All of the studies reported a decrease in ED visit frequency following their respective interventions. These reductions were especially pronounced in studies whose interventions were focused around individualized care plans and primary care involvement. Interventions implementing opioid restriction and pain management policies were largely successful in reducing the amounts of opioid medications administered and prescribed in the ED. CONCLUSIONS: Multifaceted interventions, especially those employing individualized care plans, can successfully reduce subsequent ED visits, ED opioid administration and prescription, and care-associated costs for frequent ED utilizing patients with CNCP.

Alchemical Hydration Free-Energy Calculations Using Molecular Dynamics with Explicit Polarization and Induced Polarity Decoupling: An On-the-Fly Polarization Approach.

We present a methodology using fixed charge force fields for alchemical solvation free energy calculations which accounts for the change in polarity that the solute experiences as it transfers from the gas-phase to the condensed phase. We update partial charges using QM/MM snapshots, decoupling the electric field appropriately when updating the partial charges. We also show how to account for the cost of self-polarization. We test our methodology on 30 molecules ranging from small polar to large druglike molecules. We use Minimum Basis Iterative Stockholder (MBIS), Restrained Electrostatic Potential (RESP), and AM1-BCC partial charge methodologies. Using our method with MP2/cc-pVTZ and MBIS partial charges yields an average absolute deviation (AAD) of 6.3 kJ·mol-1 in comparison with the AM1-BCC result of 8.6 kJ·mol-1. AM1-BCC is within experimental uncertainty on 10% of the data compared to 30% with our method. We conjecture that results can be further improved by using Lennard-Jones and torsional parameters refitted to MBIS and RESP partial charge methods that use high levels of theory.

Leukocyte function assessed via serial microlitre sampling of peripheral blood from sepsis patients correlates with disease severity.

Dysregulated leukocyte responses underlie the pathobiology of sepsis, which is a leading cause of death. However, measures of leukocyte function are not routinely available in clinical care. Here we report the development and testing of an inertial microfluidic system for the label-free isolation and downstream functional assessment of leukocytes from 50 µl of peripheral blood. We used the system to assess leukocyte phenotype and function in serial samples from 18 hospitalized patients with sepsis and 10 healthy subjects. The sepsis samples had significantly higher levels of CD16dim and CD16- neutrophils and CD16+ 'intermediate' monocytes, as well as significantly lower levels of neutrophil-elastase release, O2- production and phagolysosome formation. Repeated sampling of sepsis patients over 7 days showed that leukocyte activation (measured by isodielectric separation) and leukocyte phenotype and function were significantly more predictive of the clinical course than complete-blood-count parameters. We conclude that the serial assessment of leukocyte function in microlitre blood volumes is feasible and that it provides significantly more prognostic information than leukocyte counting.

Generational Patterns of Asthma Incidence among Immigrants to Canada over Two Decades. A Population-based Cohort Study.

RATIONALE: Canada, an industrialized country with high endemic asthma rates, is characterized by a large immigrant population. OBJECTIVES: We sought to provide insight into the relative contribution of environmental exposure to asthma risk by comparing asthma rates among recent immigrants relative to long-term residents of Canada. METHODS: This was a population-based, retrospective cohort study performed using provincial health administrative data for all residents of Ontario, Canada. Residents with and without a diagnosis of asthma from fiscal years 1996-2012 were included. Individuals were categorized as being immigrants (landed in Canada after 1985) or long-term residents of Ontario by linkage with the Immigration, Refugees, and Citizenship Canada's Permanent Resident Database. We calculated the age- and sex-standardized incidence of asthma among residents of Ontario, and compared the incidence of asthma among immigrants and long-term residents using incidence rate ratios (IRRs). RESULTS: Analysis of approximately 11.7 million records showed that 2.2 immigrants arrived in Canada during the study period, with over 50% from East and South Asia and the Pacific. We found that asthma incidence was lower among immigrants compared with long-term residents (IRR = 0.30; 95% confidence interval = 0.30-0.30; P < 0.001). However, Ontario-born children of immigrants from most world regions had significantly higher asthma incidence compared with children of long-term residents (IRR = 1.44; 95% confidence interval = 1.43-1.45; P < 0.001). The overall incidence of asthma in Ontario decreased between 1996 and 2012 (Ptrend < 0.001). Immigrants contributed to only a small proportion of the asthma incidence in Ontario, and changes within this group did not significantly affect trends in the overall Ontario population asthma incidence. CONCLUSIONS: The higher asthma incidence seen among children of immigrants, but not in their parents, suggests that being born in Canada was critical for determining asthma risk. These findings support the importance of in utero and/or early life exposures on asthma development.

Specialized Proresolving Mediators in Innate and Adaptive Immune Responses in Airway Diseases.

Airborne pathogens and environmental stimuli evoke immune responses in the lung. It is critical to health that these responses be controlled to prevent tissue damage and the compromise of organ function. Resolution of inflammation is a dynamic process that is coordinated by biochemical and cellular mechanisms. Recently, specialized proresolving mediators (SPMs) have been identified in resolution exudates. These molecules orchestrate anti-inflammatory and proresolving actions that are cell type specific. In this review, we highlight SPM biosynthesis, the influence of SPMs on the innate and adaptive immune responses in the lung, as well as recent insights from SPMs on inflammatory disease pathophysiology. Uncovering these mediators and cellular mechanisms for resolution is providing new windows into physiology and disease pathogenesis.

Ras Binder Induces a Modified Switch-II Pocket in GTP and GDP States.

Covalent inhibitors of K-Ras(G12C) have been reported that exclusively recognize the GDP state. Here, we utilize disulfide tethering of a non-natural cysteine (K-Ras(M72C)) to identify a new switch-II pocket (S-IIP) binding ligand (2C07) that engages the active GTP state. Co-crystal structures of 2C07 bound to H-Ras(M72C) reveal binding in a cryptic groove we term S-IIG. In the GppNHp state, 2C07 binding to a modified S-IIP pushes switch I away from the nucleotide, breaking the network of polar contacts essential for adopting the canonical GTP state. Biochemical studies show that 2C07 alters nucleotide preference and inhibits SOS binding and catalyzed nucleotide exchange. 2C07 was converted to irreversible covalent analogs, which target both nucleotide states, inhibit PI3K activation in vitro, and function as occupancy probes to detect reversible engagement in competition assays. Targeting both nucleotide states opens the possibility of inhibiting oncogenic mutants of Ras, which exist predominantly in the GTP state in cells.

Molecular mechanism of activation of class IA phosphoinositide 3-kinases (PI3Ks) by membrane-localized HRas.

Class IA PI3Ks are involved in the generation of the key lipid signaling molecule phosphatidylinositol 3,4,5-trisphosphate (PIP3), and inappropriate activation of this pathway is implicated in a multitude of human diseases, including cancer, inflammation, and primary immunodeficiencies. Class IA PI3Ks are activated downstream of the Ras superfamily of GTPases, and Ras-PI3K interaction plays a key role in promoting tumor formation and maintenance in Ras-driven tumors. Investigating the detailed molecular events in the Ras-PI3K interaction has been challenging because it occurs on a membrane surface. Here, using maleimide-functionalized lipid vesicles, we successfully generated membrane-resident HRas and evaluated its effect on PI3K signaling in lipid kinase assays and through analysis with hydrogen-deuterium exchange MS. We screened all class IA PI3K isoforms and found that HRas activates both p110α and p110δ isoforms but does not activate p110ß. The p110α and p110δ activation by Ras was synergistic with activation by a soluble phosphopeptide derived from receptor tyrosine kinases. Hydrogen-deuterium exchange MS revealed that membrane-resident HRas, but not soluble HRas, enhances conformational changes associated with membrane binding by increasing membrane recruitment of both p110α and p110δ. Together, these results afford detailed molecular insight into the Ras-PI3K signaling complex, provide a framework for screening Ras inhibitors, and shed light on the isoform specificity of Ras-PI3K interactions in a native membrane context.