Analysing Megasynthetase Mutants at High Throughput Using Droplet Microfluidics.

Nonribosomal peptide synthetases (NRPSs) are giant enzymatic assembly lines that deliver many pharmaceutically valuable natural products, including antibiotics. As the search for new antibiotics motivates attempts to redesign nonribosomal metabolic pathways, more robust and rapid sorting and screening platforms are needed. Here, we establish a microfluidic platform that reliably detects production of the model nonribosomal peptide gramicidin S. The detection is based on calcein-filled sensor liposomes yielding increased fluorescence upon permeabilization. From a library of NRPS mutants, the sorting platform enriches the gramicidin S producer 14.5-fold, decreases internal stop codons 250-fold, and generates enrichment factors correlating with enzyme activity. Screening for NRPS activity with a reliable non-binary sensor will enable more sophisticated structure-activity studies and new engineering applications in the future.

"A morning cortisol is the most effective clinical predictor of short synacthen test outcome": A tertiary care centre experience.

OBJECTIVE: Increasing referrals to Endocrinology with nonspecific symptoms of suspected adrenal insufficiency (AI) has increased use of the short-synacthen test (SST). Prevailing resource and safety concerns emphasise importance of patient selection criterion to optimise SST use. This study aimed to (1) document the adverse event profile of the SST (2) identify any pretest predictors of SST outcome. DESIGN, PATIENTS AND MEASUREMENTS: Retrospective data analysis of all patients referred for SST in Oxford from 2017 to 2021. Pretest clinical variables (age, sex, BMI, blood pressure and electrolytes), symptoms (fatigue, dizziness, weight loss) and pretest morning cortisol were included in the statistical model with the aim of identifying any variables that could predict SST outcome in Group 1 primary AI, Group 2 central AI and Group 3 glucocorticoid induced AI. Symptoms and signs during and post SST were also noted with the aim of describing adverse effects to synacthen across a large cohort. RESULTS: A total 1480 SSTs (Males:38%, age 52 [39-66] years) were performed: 505 (34.1%) in Group 1, 838 (57%) in Group 2, and 137 (9.3%) in Group 3. Adverse-effects were recorded in 1.8% of tests, including one episode of anaphylaxis. Pretest morning-cortisol was the only predictor for an "SST pass" (whole cohort: B = 0.015, p < 0.001, Group 1: B = 0.018, p < .001; Group 2: B = 0.010, p < 0.012; Group 3: B = 0.018, p = <.001). A threshold of ≥343 nmol/l (receiver-operating characteristic [ROC] area under the curve [AUC] = 0.725, 95% confidence interval [CI] 0.675-0.775, p < 0.001) for the whole cohort, ≥300 nmol/L (ROC AUC = 0.763, 95% CI 0.675 to 0.850, p < 0.001) for Group 1, ≥340 nmol/L (ROC AUC = 0.688, 95% CI 0.615 to 0.761, p < 0.001) for Group2, and ≥376 nmol/L [baseline cortisol] (ROC AUC = 0.783, 95% CI 0.708 to 0.859, p < 0.001) for Group 3, predicted an 'SST pass' with 100% specificity. CONCLUSIONS: Adverse effects to synacthen are rare. Pretest morning cortisol is a reliable predictor for SST outcome and is a helpful tool to rationalise use of the SST. Predictive morning-cortisol thresholds vary according to the aetiology of AI.

The Disclosure of Bad News Over the Phone vs. in Person and its Association with Psychological Distress: a Systematic Review and Meta-Analysis.

BACKGROUND: Communicating bad news such as a new cancer diagnosis to patients may have a major impact on their well-being. We investigated differences in patients' psychological distress due to the disclosure of bad news by telephone compared to in person in a systematic review and meta-analysis. METHODS: We included all studies that investigated anxiety, depressive or post-traumatic stress disorder (PTSD) symptoms in adult patients in whom bad news by telephone compared to in person were disclosed. We systematically searched PubMed, Embase, PsycINFO and CINAHL from the inception of each database to October 18, 2022. We included randomized and non-randomized trials. RESULTS: We screened 5944 studies and included 11 studies in the qualitative analysis and 9 in the meta-analyses, including four randomized controlled trials. Overall, the quality of studies was moderate to good. There was no difference regarding psychological distress when bad news was disclosed by telephone compared to in person with similar symptom levels of anxiety (3 studies, 285 participants; standardized mean difference [SMD] 0.10 [95% CI -0.15 to 0.35]), depression (3 studies, 284 participants; SMD 0.10 [95% CI -0.30 to 0.49]), and PTSD (2 studies, 171 participants; SMD -0.01 [95% CI -0.48 to 0.36]). Results were similar for satisfaction with care. DISCUSSION: This meta-analysis found no difference regarding psychological distress regardless if bad news were disclosed by telephone or in person, but there were overall only few and heterogeneous studies with a small number of eligible patients. The findings suggest that the modality of disclosure might play a secondary role and the way in which the bad news are communicated might be more important.

Patients' Preference for Participation in Medical Decision-Making: Secondary Analysis of the BEDSIDE-OUTSIDE Trial.

BACKGROUND: Patients may prefer different levels of involvement in decision-making regarding their medical care which may influence their medical knowledge. OBJECTIVE: We investigated associations of patients' decisional control preference (DCP) with their medical knowledge, ward round performance measures (e.g., duration, occurrence of sensitive topics), and perceived quality of care measures (e.g., trust in the healthcare team, satisfaction with hospital stay). DESIGN: This is a secondary analysis of a randomized controlled multicenter trial conducted between 2017 and 2019 at 3 Swiss teaching hospitals. PARTICIPANTS: Adult patients that were hospitalized for inpatient care. MAIN MEASURES: The primary outcome was patients' subjective average knowledge of their medical care (rated on a visual analog scale from 0 to 100). We classified patients as active, collaborative, and passive according to the Control Preference Scale. Data collection was performed before, during, and after the ward round. KEY RESULTS: Among the 761 included patients, those with a passive DCP had a similar subjective average (mean ± SD) knowledge (81.3 ± 19.4 points) compared to patients with a collaborative DCP (78.7 ± 20.3 points) and active DCP (81.3 ± 21.5 points), p = 0.25. Regarding patients' trust in physicians and nurses, we found that patients with an active vs. passive DCP reported significantly less trust in physicians (adjusted difference, - 5.08 [95% CI, - 8.69 to - 1.48 points], p = 0.006) and in nurses (adjusted difference, - 3.41 [95% CI, - 6.51 to - 0.31 points], p = 0.031). Also, patients with an active vs. passive DCP were significantly less satisfied with their hospital stay (adjusted difference, - 7.17 [95% CI, - 11.01 to - 3.34 points], p < 0.001). CONCLUSION: Patients with active DCP have lower trust in the healthcare team and lower overall satisfaction despite similar perceived medical knowledge. The knowledge of a patient's DCP may help to individualize patient-centered care. A personalized approach may improve the patient-physician relationship and increase patients' satisfaction with medical care. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03210987).

Membrane permeabilization can be crucially biased by a fusogenic lipid composition - leaky fusion caused by antimicrobial peptides in model membranes.

Induced membrane permeabilization or leakage is often taken as an indication for activity of membrane-active molecules, such as antimicrobial peptides (AMPs). The exact leakage mechanism is often unknown, but important, because certain mechanisms might actually contribute to microbial killing, while others are unselective, or potentially irrelevant in an in vivo situation. Using an antimicrobial example peptide (cR3W3), we illustrate one of the potentially misleading leakage mechanisms: leaky fusion, where leakage is coupled to membrane fusion. Like many others, we examine peptide-induced leakage in model vesicles consisting of binary mixtures of anionic and zwitterionic phospholipids. In fact, phosphatidylglycerol and phosphatidylethanolamine (PG/PE) are supposed to reflect bacterial membranes, but exhibit a high propensity for vesicle aggregation and fusion. We describe the implications of this vesicle fusion and aggregation for the reliability of model studies. The ambiguous role of the relatively fusogenic PE-lipids becomes clear as leakage decreases significantly when aggregation and fusion are prevented by sterical shielding. Furthermore, the mechanism of leakage changes if PE is exchanged for phosphatidylcholine (PC). We thus point out that the lipid composition of model membranes can be biased towards leaky fusion. This can lead to discrepancies between model studies and activity in true microbes, because leaky fusion is likely prevented by bacterial peptidoglycan layers. In conclusion, choosing the model membrane might implicate the type of effect (here leakage mechanism) that is observed. In the worst case, as with leaky fusion of PG/PE vesicles, this is not directly relevant for the intended antimicrobial application.

Diabetes disturbs functional adaptation of the remote myocardium after ischemia/reperfusion.

Diabetes mellitus type 2 is associated with adverse clinical outcome after myocardial infarction. To better understand the underlying causes we here investigated sarcomere protein function and its calcium-dependent regulation in the non-ischemic remote myocardium (RM) of diabetic mice (db/db) after transient occlusion of the left anterior descending coronary artery. Before and 24 h after surgery db/db and non-diabetic db/+ underwent magnetic resonance imaging followed by histological and biochemical analyses of heart tissue. Intracellular calcium transients and sarcomere function were measured in isolated cardiomyocytes. Active and passive force generation was assessed in skinned fibers and papillary muscle preparations. Before ischemia and reperfusion (I/R), beat-to-beat calcium cycling was depressed in diabetic cardiomyocytes. Nevertheless, contractile function was preserved owing to increased myofilament calcium sensitivity and higher responsiveness of myocardial force production to ß-adrenergic stimulation in db/db compared to db/+. In addition, protein kinase C activity was elevated in db/db hearts leading to strong phosphorylation of the titin PEVK region and increased titin-based tension of myofilaments. I/R impaired the function of whole hearts and RM sarcomeres in db/db to a larger extent than in non-diabetic db/+, and we identified several reasons. First, the amplitude and the kinetics of cardiomyocyte calcium transients were further reduced in the RM of db/db. Underlying causes involved altered expression of calcium regulatory proteins. Diabetes and I/R additively reduced phospholamban S16-phosphorylation by 80% (P < 000.1) leading to strong inhibition of the calcium ATPase SERCA2a. Second, titin stiffening was only observed in the RM of db/+, but not in the RM of db/db. Finally, db/db myofilament calcium sensitivity and force generation upon ß-adrenergic stimulation were no longer enhanced over db/+ in the RM. The findings demonstrate that impaired cardiomyocyte calcium cycling of db/db hearts is compensated by increased myofilament calcium sensitivity and increased titin-based stiffness prior to I/R. In contrast, sarcomere function of the RM 24 h after I/R is poor because both these compensatory mechanisms fail and myocyte calcium handling is further depressed.

Stress effects on memory retrieval of aversive and appetitive instrumental counterconditioning in men.

Extinction training creates a second inhibitory memory trace and effectively reduces conditioned responding. However, acute stress inhibits the retrieval of this extinction memory trace. It is not known whether this also applies to other forms of associative learning such as instrumental counterconditioning, where previously learned associations are reversed and paired with the opposite valence. Therefore, the current preregistered study investigates whether stress decreases the retrieval of instrumental counterconditioning memories with aversive and appetitive consequences. Fifty-two healthy men were randomly assigned to either a stress or control group and took part in a two-day instrumental learning paradigm. During a first phase, participants learned that pressing specific buttons in response to the presentation of four neutral stimuli either leads to gaining or losing money. During a second phase, two stimuli reversed their contingencies (counterconditioning). One day later, participants were exposed to acute stress or a control condition prior to the same task, which no longer included feedback about gains or losses. Stressed participants showed more approach behavior towards appetitive and less avoidance behavior towards aversive stimuli as compared to non-stressed participants. Our findings indicate that stress effects on memory retrieval differ depending on the associative learning approach in men. These differences might be related to stress effects on decision making and different motivational systems involved.

Predicting neurological outcome in adult patients with cardiac arrest: systematic review and meta-analysis of prediction model performance.

This work aims to assess the performance of two post-arrest (out-of-hospital cardiac arrest, OHCA, and cardiac arrest hospital prognosis, CAHP) and one pre-arrest (good outcome following attempted resuscitation, GO-FAR) prediction model for the prognostication of neurological outcome after cardiac arrest in a systematic review and meta-analysis. A systematic search was conducted in Embase, Medline, and Web of Science Core Collection from November 2006 to December 2021, and by forward citation tracking of key score publications. The search identified 1'021 records, of which 25 studies with a total of 124'168 patients were included in the review. A random-effects meta-analysis of C-statistics and overall calibration (total observed vs. expected [O:E] ratio) was conducted. Discriminatory performance was good for the OHCA (summary C-statistic: 0.83 [95% CI 0.81-0.85], 16 cohorts) and CAHP score (summary C-statistic: 0.84 [95% CI 0.82-0.87], 14 cohorts) and acceptable for the GO-FAR score (summary C-statistic: 0.78 [95% CI 0.72-0.84], five cohorts). Overall calibration was good for the OHCA (total O:E ratio: 0.78 [95% CI 0.67-0.92], nine cohorts) and the CAHP score (total O:E ratio: 0.78 [95% CI 0.72-0.84], nine cohorts) with an overestimation of poor outcome. Overall calibration of the GO-FAR score was poor with an underestimation of good outcome (total O:E ratio: 1.62 [95% CI 1.28-2.04], five cohorts). Two post-arrest scores showed good prognostic accuracy for predicting neurological outcome after cardiac arrest and may support early discussions about goals-of-care and therapeutic planning on the intensive care unit. A pre-arrest score showed acceptable prognostic accuracy and may support code status discussions.

Effect of Bedside Compared With Outside the Room Patient Case Presentation on Patients' Knowledge About Their Medical Care : A Randomized, Controlled, Multicenter Trial.

BACKGROUND: Although bedside case presentation contributes to patient-centered care through active patient participation in medical discussions, the complexity of medical information and jargon-induced confusion may cause misunderstandings and patient discomfort. OBJECTIVE: To compare bedside versus outside the room patient case presentation regarding patients' knowledge about their medical care. DESIGN: Randomized, controlled, parallel-group trial. (ClinicalTrials.gov: NCT03210987). SETTING: 3 Swiss teaching hospitals. PATIENTS: Adult medical patients who were hospitalized. INTERVENTION: Patients were randomly assigned to bedside or outside the room case presentation. MEASUREMENTS: The primary endpoint was patients' average knowledge of 3 dimensions of their medical care (each rated on a visual analogue scale from 0 to 100): understanding their disease, the therapeutic approach being used, and further plans for care. RESULTS: Compared with patients in the outside the room group (n = 443), those in the bedside presentation group (n = 476) reported similar knowledge about their medical care (mean, 79.5 points [SD, 21.6] vs. 79.4 points [SD, 19.8]; adjusted difference, 0.09 points [95% CI, -2.58 to 2.76 points]; P = 0.95). Also, an objective rating of patient knowledge by the study team was similar for the 2 groups, but the bedside presentation group had higher ratings of confusion about medical jargon and uncertainty caused by team discussions. Bedside ward rounds were more efficient (mean, 11.89 minutes per patient [SD, 4.92] vs. 14.14 minutes per patient [SD, 5.65]; adjusted difference, -2.31 minutes [CI, -2.98 to -1.63 minutes]; P < 0.001). LIMITATION: Only Swiss hospitals and medical patients were included. CONCLUSION: Compared with outside the room case presentation, bedside case presentation was shorter and resulted in similar patient knowledge, but sensitive topics were more often avoided and patient confusion was higher. Physicians presenting at the bedside need to be skilled in the use of medical language to avoid confusion and misunderstandings. PRIMARY FUNDING SOURCE: Swiss National Foundation (10531C_ 182422).

Serum neurofilament measurement improves clinical risk scores for outcome prediction after cardiac arrest: results of a prospective study.

BACKGROUND: A recent study found serum neurofilament light chain (NfL) levels to be strongly associated with poor neurological outcome in patients after cardiac arrest. Our aim was to confirm these findings in an independent validation study and to investigate whether NfL improves the prognostic value of two cardiac arrest-specific risk scores. METHODS: This prospective, single-center study included 164 consecutive adult after out-of-hospital cardiac arrest (OHCA) patients upon intensive care unit admission. We calculated two clinical risk scores (OHCA, CAHP) and measured NfL on admission within the first 24 h using the single molecule array NF-light® assay. The primary endpoint was neurological outcome at hospital discharge assessed with the cerebral performance category (CPC) score. RESULTS: Poor neurological outcome (CPC > 3) was found in 60% (98/164) of patients, with 55% (91/164) dying within 30 days of hospitalization. Compared to patients with favorable outcome, NfL was 14-times higher in patients with poor neurological outcome (685 ± 1787 vs. 49 ± 111 pg/mL), with an adjusted odds ratio of 3.4 (95% CI 2.1 to 5.6, p < 0.001) and an area under the curve (AUC) of 0.82. Adding NfL to the clinical risk scores significantly improved discrimination of both the OHCA score (from AUC 0.82 to 0.89, p < 0.001) and CAHP score (from AUC 0.89 to 0.92, p < 0.05). Adding NfL to both scores also resulted in significant improvement in reclassification statistics with a Net Reclassification Index (NRI) of 0.58 (p < 0.001) for OHCA and 0.83 (p < 0.001) for CAHP. CONCLUSIONS: Admission NfL was a strong outcome predictor and significantly improved two clinical risk scores regarding prognostication of neurological outcome in patients after cardiac arrest. When confirmed in future outcome studies, admission NfL should be considered as a standard laboratory measures in the evaluation of OHCA patients.

Association of medical futility with do-not-resuscitate (DNR) code status in hospitalised patients.

Guidelines recommend a 'do-not-resuscitate' (DNR) code status for inpatients in which cardiopulmonary resuscitation (CPR) attempts are considered futile because of low probability of survival with good neurological outcome. We retrospectively assessed the prevalence of DNR code status and its association with presumed CPR futility defined by the Good Outcome Following Attempted Resuscitation score and the Clinical Frailty Scale in patients hospitalised in the Divisions of Internal Medicine and Traumatology/Orthopedics at the University Hospital of Basel between September 2018 and June 2019. The definition of presumed CPR futility was met in 467 (16.2%) of 2889 patients. 866 (30.0%) patients had a DNR code status. In a regression model adjusted for age, gender, main diagnosis, nationality, language and religion, presumed CPR futility was associated with a higher likelihood of a DNR code status (37.3% vs 7.1%, adjusted OR 2.99, 95% CI 2.31 to 3.88, p<0.001). In the subgroup of patients with presumed futile CPR, 144 of 467 (30.8%) had a full code status, which was independently associated with younger age, male gender, non-Christian religion and non-Swiss citizenship. We found a significant proportion of hospitalised patients to have a full code status despite the fact that CPR had to be considered futile according to an established definition. Whether these decisions were based on patient preferences or whether there was a lack of patient involvement in decision-making needs further investigation.

Drug-induced endocrine blood pressure elevation.

Patients with uncontrolled hypertension are at risk for cardiovascular complications. The majority of them suffers from unidentified forms of hypertension and a fraction has so-called secondary hypertension with an identifiable cause. The patient's medications, its use of certain herbal supplements and over-the-counter agents represent potential causal factors for secondary hypertension that are often overlooked. The current review focuses on drugs that are likely to elevate blood pressure by affecting the human endocrine system at the level of steroid synthesis or metabolism, mineralocorticoid receptor activity, or by affecting the catecholaminergic system. Drugs with known adverse effects but where benefits outweigh their risks, drug candidates and market withdrawals are reviewed. Finally, potential therapeutic strategies are discussed.

Trimethylamine-N-oxide (TMAO) predicts short- and long-term mortality and poor neurological outcome in out-of-hospital cardiac arrest patients.

Objectives: Prior research found the gut microbiota-dependent and pro-atherogenic molecule trimethylamine-N-oxide (TMAO) to be associated with cardiovascular events as well as all-cause mortality in different patient populations with cardiovascular disease. Our aim was to investigate the prognostic value of TMAO regarding clinical outcomes in patients after out-of-hospital cardiac arrest (OHCA). Methods: We included consecutive OHCA patients upon intensive care unit admission into this prospective observational study between October 2012 and May 2016. We studied associations of admission serum TMAO with in-hospital mortality (primary endpoint), 90-day mortality and neurological outcome defined by the Cerebral Performance Category (CPC) scale. Results: We included 258 OHCA patients of which 44.6% died during hospitalization. Hospital non-survivors showed significantly higher admission TMAO levels (µmol L-1) compared to hospital survivors (median interquartile range (IQR) 13.2 (6.6-34.9) vs. 6.4 (2.9-15.9), p<0.001). After multivariate adjustment for other prognostic factors, TMAO levels were significantly associated with in-hospital mortality (adjusted odds ratios (OR) 2.1, 95%CI 1.1-4.2, p=0.026). Results for secondary outcomes were similar with significant associations with 90-day mortality and neurological outcome in univariate analyses. Conclusions: In patients after OHCA, TMAO levels were independently associated with in-hospital mortality and other adverse clinical outcomes and may help to improve prognostication for these patients in the future. Whether TMAO levels can be influenced by nutritional interventions should be addressed in future studies.

Predictors of study drop-out and service disengagement in patients at clinical high risk for psychosis.

PURPOSE: Study drop-out during follow-up and service disengagement frequently occur in patients at clinical high risk for psychosis (CHR-P). However, little is known about their predictors. Therefore, we aimed to analyze the rate and reasons for drop-out and service disengagement in CHR-P patients and investigate their sociodemographic and clinical predictors. METHODS: Data from 200 patients of the prospective Früherkennung von Psychosen (FePsy) study were analyzed with competing risks survival models, considering drop-out and transition to psychosis as competing events. To investigate whether symptoms changed immediately before drop-out, t tests were applied. RESULTS: Thirty-six percent of patients dropped out within 5 years. Almost all drop-outs also disengaged from our service. Hence, study drop-out was used as a proxy for service disengagement. Patients with more severe baseline disorganized symptoms and a late inclusion into the study were significantly more likely to disengage. Immediately before disengagement, there was significant improvement in negative symptoms only. CONCLUSION: A considerable proportion of CHR-P patients disengaged from our clinical study and service. Patients who were included during a later study period with more assessments disengaged more often, which might have been due to more frequent invitations to follow-up assessments and thereby increasing participation burden. Hence, our study provides a cautionary note on high-frequency follow-up assessments. Larger-scale studies evaluating predictors on multiple domains would help to further elucidate drop-out and disengagement.

11ß-Hydroxysteroid dehydrogenases control access of 7ß,27-dihydroxycholesterol to retinoid-related orphan receptor γ.

Oxysterols previously were considered intermediates of bile acid and steroid hormone biosynthetic pathways. However, recent research has emphasized the roles of oxysterols in essential physiologic processes and in various diseases. Despite these discoveries, the metabolic pathways leading to the different oxysterols are still largely unknown and the biosynthetic origin of several oxysterols remains unidentified. Earlier studies demonstrated that the glucocorticoid metabolizing enzymes, 11ß-hydroxysteroid dehydrogenase (11ß-HSD) types 1 and 2, interconvert 7-ketocholesterol (7kC) and 7ß-hydroxycholesterol (7ßOHC). We examined the role of 11ß-HSDs in the enzymatic control of the intracellular availability of 7ß,27-dihydroxycholesterol (7ß27OHC), a retinoid-related orphan receptor γ (RORγ) ligand. We used microsomal preparations of cells expressing recombinant 11ß-HSD1 and 11ß-HSD2 to assess whether 7ß27OHC and 7-keto,27-hydroxycholesterol (7k27OHC) are substrates of these enzymes. Binding of 7ß27OHC and 7k27OHC to 11ß-HSDs was studied by molecular modeling. To our knowledge, the stereospecific oxoreduction of 7k27OHC to 7ß27OHC by human 11ß-HSD1 and the reverse oxidation reaction of 7ß27OHC to 7k27OHC by human 11ß-HSD2 were demonstrated for the first time. Apparent enzyme affinities of 11ß-HSDs for these novel substrates were equal to or higher than those of the glucocorticoids. This is supported by the fact that 7k27OHC and 7ß27OHC are potent inhibitors of the 11ß-HSD1-dependent oxoreduction of cortisone and the 11ß-HSD2-dependent oxidation of cortisol, respectively. Furthermore, molecular docking calculations explained stereospecific enzyme activities. Finally, using an inducible RORγ reporter system, we showed that 11ß-HSD1 and 11ß-HSD2 controlled RORγ activity. These findings revealed a novel glucocorticoid-independent prereceptor regulation mechanism by 11ß-HSDs that warrants further investigation.

Profiling withanolide A for therapeutic targets in neurodegenerative diseases.

To identify new potential therapeutic targets for neurodegenerative diseases, we initiated activity-based protein profiling studies with withanolide A (WitA), a known neuritogenic constituent of Withania somnifera root with unknown mechanism of action. Molecular probes were designed and synthesized, and led to the discovery of the glucocorticoid receptor (GR) as potential target. Molecular modeling calculations using the VirtualToxLab predicted a weak binding affinity of WitA for GR. Neurite outgrowth experiments in human neuroblastoma SH-SY5Y cells further supported a glucocorticoid-dependent mechanism, finding that WitA was able to reverse the outgrowth inhibition mediated by dexamethasone (Dex). However, further GR binding and transactivation assays found no direct interference of WitA. Further molecular modeling analysis suggested that WitA, although forming several contacts with residues in the GR binding pocket, is lacking key stabilizing interactions as observed for Dex. Taken together, the data suggest that WitA-dependent induction of neurite outgrowth is not through a direct effect on GR, but might be mediated through a closely related pathway. Further experiments should evaluate a possible role of GR modulators and/or related signaling pathways such as ERK, Akt, NF-κB, TRα, or Hsp90 as potential targets in the WitA-mediated neuromodulatory effects.

Nitrergic signalling via interstitial cells of Cajal regulates motor activity in murine colon.

In the enteric nervous systems, NO is released from nitrergic neurons as a major inhibitory neurotransmitter. NO acts via NO-sensitive guanylyl cyclase (NO-GC), which is found in different gastrointestinal (GI) cell types including smooth muscle cells (SMCs) and interstitial cells of Cajal (ICC). The precise mechanism of nitrergic signalling through these two cell types to regulate colonic spontaneous contractions is not fully understood yet. In the present study we investigated the impact of endogenous and exogenous NO on colonic contractile motor activity using mice lacking nitric oxide-sensitive guanylyl cyclase (NO-GC) globally and specifically in SMCs and ICC. Longitudinal smooth muscle of proximal colon from wild-type (WT) and knockout (KO) mouse strains exhibited spontaneous contractile activity ex vivo. WT and smooth muscle-specific guanylyl cyclase knockout (SMC-GCKO) colon showed an arrhythmic contractile activity with varying amplitudes and frequencies. In contrast, colon from global and ICC-specific guanylyl cyclase knockout (ICC-GCKO) animals showed a regular contractile rhythm with constant duration and amplitude of the rhythmic contractions. Nerve blockade (tetrodotoxin) or specific blockade of NO signalling (L-NAME, ODQ) did not significantly affect contractions of GCKO and ICC-GCKO colon whereas the arrhythmic contractile patterns of WT and SMC-GCKO colon were transformed into uniform motor patterns. In contrast, the response to electric field-stimulated neuronal NO release was similar in SMC-GCKO and global GCKO. In conclusion, our results indicate that basal enteric NO release acts via myenteric ICC to influence the generation of spontaneous contractions whereas the effects of elevated endogenous NO are mediated by SMCs in the murine proximal colon.

Pharmacophore Models and Pharmacophore-Based Virtual Screening: Concepts and Applications Exemplified on Hydroxysteroid Dehydrogenases.

Computational methods are well-established tools in the drug discovery process and can be employed for a variety of tasks. Common applications include lead identification and scaffold hopping, as well as lead optimization by structure-activity relationship analysis and selectivity profiling. In addition, compound-target interactions associated with potentially harmful effects can be identified and investigated. This review focuses on pharmacophore-based virtual screening campaigns specifically addressing the target class of hydroxysteroid dehydrogenases. Many members of this enzyme family are associated with specific pathological conditions, and pharmacological modulation of their activity may represent promising therapeutic strategies. On the other hand, unintended interference with their biological functions, e.g., upon inhibition by xenobiotics, can disrupt steroid hormone-mediated effects, thereby contributing to the development and progression of major diseases. Besides a general introduction to pharmacophore modeling and pharmacophore-based virtual screening, exemplary case studies from the field of short-chain dehydrogenase/reductase (SDR) research are presented. These success stories highlight the suitability of pharmacophore modeling for the various application fields and suggest its application also in futures studies.

Imaging atherosclerotic plaque inflammation via folate receptor targeting using a novel 18F-folate radiotracer.

Folate receptor ß (FR-ß) is overexpressed on activated, but not resting, macrophages involved in a variety of inflammatory and autoimmune diseases. A pivotal step in atherogenesis is the subendothelial accumulation of macrophages. In nascent lesions, they coordinate the scavenging of lipids and cellular debris to define the likelihood of plaque inflammation and eventually rupture. In this study, we determined the presence of FR-ß-expressing macrophages in atherosclerotic lesions by the use of a fluorine-18-labeled folate-based radiotracer. Human endarterectomized specimens were used to measure gene expression levels of FR-ß and CD68. Increased FR-ß and CD68 levels were found in atherosclerotic plaques compared to normal artery walls by quantitative real-time polymerase chain reaction. Western blotting and immunohistochemistry demonstrated prominent FR-ß protein levels in plaques. FR-ß-positive cells colocalized with activated macrophages (CD68) in plaque tissue. Carotid sections incubated with 3'-aza-2'-[18F]fluorofolic acid displayed increased accumulation in atherosclerotic plaques through in vitro autoradiography. Specific binding of the radiotracer correlated with FR-ß-expressing macrophages. These results demonstrate high FR-ß expression in atherosclerotic lesions of human carotid tissue correlating with CD68-positive macrophages. Areas of high 3'-aza-2'-[18F]fluorofolic acid binding within the lesions represented FR-ß-expressing macrophages. Selectively targeting FR-ß-positive macrophages through folate-based radiopharmaceuticals may be useful for noninvasive imaging of plaque inflammation.