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.

Occurrence of sensitive topics during ward round: an ancillary analysis of the BEDSIDE-OUTSIDE trial.

OBJECTIVE: Discussing sensitive topics (eg, medical uncertainty, social issues, non-adherence) during ward rounds is challenging and may negatively impact patient satisfaction with the healthcare they are receiving. In the previous multicentre randomised BEDSIDE-OUTSIDE trial focusing on communication during ward rounds, we investigated the interplay between sensitive topics and low reported satisfaction with care. DESIGN: Pre-planned secondary analysis of a randomised controlled trial. For this analysis data of the original trial was pooled across intervention groups. SETTING: Three Swiss teaching hospitals. PARTICIPANTS: Adult patients hospitalised for medical care. INTERVENTIONS: We analysed predefined sensitive health topics and specific elements of communication from audiotapes recorded during ward rounds, for both patients dealing with and without sensitive topics. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary endpoint was overall patient satisfaction with care; measured on a Visual Analogue Scale from 0 to 100. Secondary endpoints included duration of ward rounds and further satisfaction outcomes. RESULTS: Of the 919 included patients, 474 had at least one sensitive topic including medical uncertainty (n=251), psychiatric comorbidities (n=161), tumour diagnosis (n=137) and social issues (n=125). Compared with patients without sensitive topics, patients with sensitive topics reported lower satisfaction with care (mean (SD), 87.7 (±14.6) vs 90.2 (±12.1), adjusted difference -2.5 (95% CI -4.28 to -0.72), p=0.006. Among patients with sensitive topics, risk factors for low satisfaction included several parameters concerning patient-physician interaction such as disagreements during ward rounds (mean (SD), 14/212 (6.6%) vs 41/254 (16.1%), adjusted OR 2.78 (95% CI 1.47 to 5.27), p=0.002). CONCLUSIONS: A large proportion of medical inpatients must deal with sensitive health topics. This is associated with lower satisfaction with care, particularly if the patient perceives the interaction with doctors during ward rounds as unsatisfactory. Educating physicians on specific communication techniques may help improve care for these patients. TRIAL REGISTRATION NUMBER: NCT03210987.

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.

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.

Profiling of anabolic androgenic steroids and selective androgen receptor modulators for interference with adrenal steroidogenesis.

Anabolic-androgenic steroids (AAS) are testosterone derivatives developed for steroid-replacement and treatment of debilitating conditions. They are widely used by athletes in elite sports and bodybuilding due to their muscle-building and performance-enhancing properties. Excessive AAS use is associated with cardiovascular diseases, mood changes, endocrine and metabolic disorders; however, the underlying mechanisms remain unknown. Selective androgen receptor modulators (SARMs) aim to reduce adverse androgenic effects, while maximizing anabolic effects. This study assessed potential steroidogenic disturbances of 19 AAS and 3 SARMs in human adrenocortical carcinoma H295R cells, comparing basal and forskolin-activated states by mass spectrometry-based quantification of nine major adrenal steroids. Mesterolone, mestanolone and methenolone increased mineralocorticoid but decreased adrenal androgen production, indicating CYP17A1 dysfunction. Cell-free activity assays failed to detect direct CYP17A1 inhibition, supported by molecular modeling. The mRNA expression levels of 3ß-HSD2, CYP17A1, CYP21A2, CYP11B1 and CYP11B2 were unaffected, suggesting indirect inhibition involving post-translational modification and/or impaired protein stability. Clostebol and oxymetholone decreased corticosteroid but increased dehydroepiandrosterone biosynthesis in H295R cells, suggesting CYP21A2 inhibition, sustained by molecular modeling. These AAS did not affect the expression of key steroidogenic genes. None of the SARMs tested interfered with steroidogenesis. The chosen approach allowed the grouping of AAS according to their steroidogenic-disrupting effects and provided initial mechanistic information. Mesterolone, mestanolone and methenolone potentially promote hypertension and cardiovascular diseases via excessive mineralocorticoid biosynthesis. Clostebol and oxymetholone might cause metabolic disturbances by suppressing corticosteroid production, resulting in adrenal hyperplasia. The non-steroidal SARMs exhibit an improved safety profile and represent a preferred therapeutic option.

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.

Exploring the predictive power of the unspecific risk category of the Basel Screening Instrument for Psychosis.

AIM: Ultrahigh risk (UHR) criteria, consisting of brief limited intermittent psychotic symptoms (BLIPS), attenuated psychotic symptoms (APS) and genetic risk and deterioration (GRD) syndrome are the most widely used criteria for assessing the clinical high-risk state for psychosis (CHR-P). The Basel Screening Instrument for Psychosis (BSIP) includes a further risk category, the unspecific risk category (URC). However, little is known about the predictive power of this risk category compared to other risk categories. METHODS: Two hundred CHR-P patients were detected as part of the Früherkennung von Psychosen (FePsy) study using the BSIP. Transition to psychosis was assessed in regular intervals for up to 7 years. RESULTS: Patients meeting only the URC criterion (n = 40) had a significantly lower risk of transition to psychosis than the UHR group (including BLIPS, APS and GRD) (HR 0.19 [0.05; 0.80] (P = 0.024). Furthermore, the URC only risk group had a lower transition risk than the APS without BLIPS group (P = 0.015) and a trendwise lower risk than the BLIPS group (P = 0.066). However, despite the lower transition risk in the URC only group, there were still two patients (5%) in this group with a later transition to psychosis. CONCLUSIONS: The URC includes patients who have a lower risk of transition than those included by the UHR categories and thereby increases the sensitivity of the BSIP. This offers the possibility of a stratified intervention, with these subjects receiving low intensity follow-up and treatment.

DHRS7 (SDR34C1) - A new player in the regulation of androgen receptor function by inactivation of 5α-dihydrotestosterone?

DHRS7 (SDR34C1) has been associated with potential tumor suppressor effects in prostate cancer; however, its function remains largely unknown. Recent experiments using purified recombinant human DHRS7 suggested several potential substrates, including the steroids cortisone and Δ4-androstene-3,17-dione (androstenedione). However, the substrate and cofactor concentrations used in these experiments were very high and the physiological relevance of these observations needed to be further investigated. In the present study, recombinant human DHRS7 was expressed in intact HEK-293 cells in order to investigate whether glucocorticoids and androgens serve as substrates at sub-micromolar concentrations and at physiological cofactor concentrations. Furthermore, the membrane topology of DHRS7 was revisited using redox-sensitive green-fluorescent protein fusions in living cells. The results revealed that (1) cortisone is a substrate of DHRS7; however, it is not reduced to cortisol but to 20ß-dihydrocortisone, (2) androstenedione is not a relevant substrate of DHRS7, (3) DHRS7 catalyzes the oxoreduction of 5α-dihydrotestosterone (5αDHT) to 3α-androstanediol (3αAdiol), with a suppressive effect on androgen receptor (AR) transcriptional activity, and (4) DHRS7 is anchored in the endoplasmic reticulum membrane with a cytoplasmic orientation. Together, the results show that DHRS7 is a cytoplasmic oriented enzyme exhibiting 3α/20ß-hydroxysteroid dehydrogenase activity, with a possible role in the modulation of AR function. Further research needs to address the physiological relevance of DHRS7 in the inactivation of 5αDHT and AR regulation.

Virtual screening applications in short-chain dehydrogenase/reductase research.

Several members of the short-chain dehydrogenase/reductase (SDR) enzyme family play fundamental roles in adrenal and gonadal steroidogenesis as well as in the metabolism of steroids, oxysterols, bile acids, and retinoids in peripheral tissues, thereby controlling the local activation of their cognate receptors. Some of these SDRs are considered as promising therapeutic targets, for example to treat estrogen-/androgen-dependent and corticosteroid-related diseases, whereas others are considered as anti-targets as their inhibition may lead to disturbances of endocrine functions, thereby contributing to the development and progression of diseases. Nevertheless, the physiological functions of about half of all SDR members are still unknown. In this respect, in silico tools are highly valuable in drug discovery for lead molecule identification, in toxicology screenings to facilitate the identification of hazardous chemicals, and in fundamental research for substrate identification and enzyme characterization. Regarding SDRs, computational methods have been employed for a variety of applications including drug discovery, enzyme characterization and substrate identification, as well as identification of potential endocrine disrupting chemicals (EDC). This review provides an overview of the efforts undertaken in the field of virtual screening supported identification of bioactive molecules in SDR research. In addition, it presents an outlook and addresses the opportunities and limitations of computational modeling and in vitro validation methods.

Gene expression levels of matrix metalloproteinases in human atherosclerotic plaques and evaluation of radiolabeled inhibitors as imaging agents for plaque vulnerability.

INTRODUCTION: Atherosclerotic plaque rupture is the primary cause for myocardial infarction and stroke. During plaque progression macrophages and mast cells secrete matrix-degrading proteolytic enzymes, such as matrix metalloproteinases (MMPs). We studied levels of MMPs and tissue inhibitor of metalloproteinases-3 (TIMP-3) in relation to the characteristics of carotid plaques. We evaluated in vitro two radiolabeled probes targeting active MMPs towards non-invasive imaging of rupture-prone plaques. METHODS: Human carotid plaques obtained from endarterectomy were classified into stable and vulnerable by visual and histological analysis. MMP-1, MMP-2, MMP-8, MMP-9, MMP-10, MMP-12, MMP-14, TIMP-3, and CD68 levels were investigated by quantitative polymerase chain reaction. Immunohistochemistry was used to localize MMP-2 and MMP-9 with respect to CD68-expressing macrophages. Western blotting was applied to detect their active forms. A fluorine-18-labeled MMP-2/MMP-9 inhibitor and a tritiated selective MMP-9 inhibitor were evaluated by in vitro autoradiography as potential lead structures for non-invasive imaging. RESULTS: Gene expression levels of all MMPs and CD68 were elevated in plaques. MMP-1, MMP-9, MMP-12 and MMP-14 were significantly higher in vulnerable than stable plaques. TIMP-3 expression was highest in stable and low in vulnerable plaques. Immunohistochemistry revealed intensive staining of MMP-9 in vulnerable plaques. Western blotting confirmed presence of the active form in plaque lysates. In vitro autoradiography showed binding of both inhibitors to stable and vulnerable plaques. CONCLUSIONS: MMPs differed in their expression patterns among plaque phenotypes, providing possible imaging targets. The two tested MMP-2/MMP-9 and MMP-9 inhibitors may be useful to detect atherosclerotic plaques, but not the vulnerable lesions selectively.