Protein Quality Control of the Endoplasmic Reticulum and Ubiquitin-Proteasome-Triggered Degradation of Aberrant Proteins: Yeast Pioneers the Path.

Cells must constantly monitor the integrity of their macromolecular constituents. Proteins are the most versatile class of macromolecules but are sensitive to structural alterations. Misfolded or otherwise aberrant protein structures lead to dysfunction and finally aggregation. Their presence is linked to aging and a plethora of severe human diseases. Thus, misfolded proteins have to be rapidly eliminated. Secretory proteins constitute more than one-third of the eukaryotic proteome. They are imported into the endoplasmic reticulum (ER), where they are folded and modified. A highly elaborated machinery controls their folding, recognizes aberrant folding states, and retrotranslocates permanently misfolded proteins from the ER back to the cytosol. In the cytosol, they are degraded by the highly selective ubiquitin-proteasome system. This process of protein quality control followed by proteasomal elimination of the misfolded protein is termed ER-associated degradation (ERAD), and it depends on an intricate interplay between the ER and the cytosol.

eIF3 Associates with 80S Ribosomes to Promote Translation Elongation, Mitochondrial Homeostasis, and Muscle Health.

eIF3, a multi-subunit complex with numerous functions in canonical translation initiation, is known to interact with 40S and 60S ribosomal proteins and translation elongation factors, but a direct involvement in translation elongation has never been demonstrated. We found that eIF3 deficiency reduced early ribosomal elongation speed between codons 25 and 75 on a set of ∼2,700 mRNAs encoding proteins associated with mitochondrial and membrane functions, resulting in defective synthesis of their encoded proteins. To promote elongation, eIF3 interacts with 80S ribosomes translating the first ∼60 codons and serves to recruit protein quality-control factors, functions required for normal mitochondrial physiology. Accordingly, eIF3e+/- mice accumulate defective mitochondria in skeletal muscle and show a progressive decline in muscle strength. Hence, eIF3 interacts with 80S ribosomes to enhance, at the level of early elongation, the synthesis of proteins with membrane-associated functions, an activity that is critical for mitochondrial physiology and muscle health.

eIF3 mRNA selectivity profiling reveals eIF3k as a cancer-relevant regulator of ribosome content.

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA-selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo-complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5'-UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k-l as a mRNA-specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress.

Dual roles of HSP70 chaperone HSPA1 in quality control of nascent and newly synthesized proteins.

Exposure to heat stress triggers a well-defined acute response marked by HSF1-dependent transcriptional upregulation of heat shock proteins. Cells allowed to recover acquire thermotolerance, but this adaptation is poorly understood. By quantitative proteomics, we discovered selective upregulation of HSP70-family chaperone HSPA1 and its co-factors, HSPH1 and DNAJB1, in MCF7 breast cancer cells acquiring thermotolerance. HSPA1 was found to have dual function during heat stress response: (i) During acute stress, it promotes the recruitment of the 26S proteasome to translating ribosomes, thus poising cells for rapid protein degradation and resumption of protein synthesis upon recovery; (ii) during thermotolerance, HSPA1 together with HSPH1 maintains ubiquitylated nascent/newly synthesized proteins in a soluble state required for their efficient proteasomal clearance. Consistently, deletion of HSPH1 impedes thermotolerance and esophageal tumor growth in mice, thus providing a potential explanation for the poor prognosis of digestive tract cancers with high HSPH1 and nominating HSPH1 as a cancer drug target. We propose dual roles of HSPA1 either alone or in complex with HSPH1 and DNAJB1 in promoting quality control of nascent/newly synthesized proteins and cellular thermotolerance.

A case of hemorrhage at the junctions of the posterior intercostal arteries-a vital sign?

The authors present the case of a 58-year-old man found hanging from a radiator by his shoelaces. The time of death was approximately 6 h before the body was discovered. An autopsy was performed approximately 24 h after the body was found, which revealed hemorrhages in the thoracic aorta at the junctions of the posterior intercostal arteries. Before autopsy, a routine whole-body CT scan was performed. Histologic examination of the aorta and the posterior intercostal arteries revealed a fresh hemorrhage into the tunica adventitia of the aorta. To our knowledge, there is no case description of such findings in hanged persons in the literature. Conclusion: Hemorrhages into the tunica adventitia of the junction of the posterior costal arteries may occur in association with suicidal hanging. The significance of these hemorrhages as a sign of vitality may be debated.

Parallel in-depth analysis of repeat expansions in ataxia patients by long-read sequencing.

Instability of simple DNA repeats has been known as a common cause of hereditary ataxias for over 20 years. Routine genetic diagnostics of these phenotypically similar diseases still rely on an iterative workflow for quantification of repeat units by PCR-based methods of limited precision. We established and validated clinical nanopore Cas9-targeted sequencing, an amplification-free method for simultaneous analysis of 10 repeat loci associated with clinically overlapping hereditary ataxias. The method combines target enrichment by CRISPR-Cas9, Oxford Nanopore long-read sequencing and a bioinformatics pipeline using the tools STRique and Megalodon for parallel detection of length, sequence, methylation and composition of the repeat loci. Clinical nanopore Cas9-targeted sequencing allowed for the precise and parallel analysis of 10 repeat loci associated with adult-onset ataxia and revealed additional parameter such as FMR1 promotor methylation and repeat sequence required for diagnosis at the same time. Using clinical nanopore Cas9-targeted sequencing we analysed 100 clinical samples of undiagnosed ataxia patients and identified causative repeat expansions in 28 patients. Parallel repeat analysis enabled a molecular diagnosis of ataxias independent of preconceptions on the basis of clinical presentation. Biallelic expansions within RFC1 were identified as the most frequent cause of ataxia. We characterized the RFC1 repeat composition of all patients and identified a novel repeat motif, AGGGG. Our results highlight the power of clinical nanopore Cas9-targeted sequencing as a readily expandable workflow for the in-depth analysis and diagnosis of phenotypically overlapping repeat expansion disorders.

Rfu1: stimulus for the ubiquitin economy.

During cellular stress, monoubiquitin is in demand due to the accumulation of misfolded proteins that require proteasomal degradation. Kimura et al. (2009) now show in yeast that monoubiquitin levels are bolstered during stress conditions by downregulation of the protein Rfu1, an inhibitor of the deubiquitinating enzyme Doa4.

Transcript capture and ultradeep long-read RNA sequencing (CAPLRseq) to diagnose HNPCC/Lynch syndrome.

PURPOSE: Whereas most human genes encode multiple mRNA isoforms with distinct function, clinical workflows for assessing this heterogeneity are not readily available. This is a substantial shortcoming, considering that up to 25% of disease-causing gene variants are suspected of disrupting mRNA splicing or mRNA abundance. Long-read sequencing can readily portray mRNA isoform diversity, but its sensitivity is relatively low due to insufficient transcriptome penetration. METHODS: We developed and applied capture-based target enrichment from patient RNA samples combined with Oxford Nanopore long-read sequencing for the analysis of 123 hereditary cancer transcripts (capture and ultradeep long-read RNA sequencing (CAPLRseq)). RESULTS: Validating CAPLRseq, we confirmed 17 cases of hereditary non-polyposis colorectal cancer/Lynch syndrome based on the demonstration of splicing defects and loss of allele expression of mismatch repair genes MLH1, PMS2, MSH2 and MSH6. Using CAPLRseq, we reclassified two variants of uncertain significance in MSH6 and PMS2 as either likely pathogenic or benign. CONCLUSION: Our data show that CAPLRseq is an automatable and adaptable workflow for effective transcriptome-based identification of disease variants in a clinical diagnostic setting.

Imaging of alert patients after non-self-inflicted strangulation: MRI is superior to CT.

OBJECTIVE: To assess the accuracy of CT and MRI reports of alert patients presenting after non-self-inflicted strangulation (NSIS) and evaluate the appropriateness of these imaging modalities in NSIS. MATERIAL AND METHODS: The study was a retrospective analysis of patient characteristics and strangulation details, with a comparison of original radiology reports (ORR) to expert read-outs (EXR) of CT and MRI studies of all NSIS cases seen from 2008 to 2020 at a single centre. RESULTS: The study included 116 patients (71% women, p < .001, χ2), with an average age of 33.8 years, mostly presenting after manual strangulation (97%). Most had experienced intimate partner violence (74% of women, p < .001, χ2) or assault by unknown offender (88% of men, p < 0.002 χ2). Overall, 132 imaging studies (67 CT, 51% and 65 MRI, 49%) were reviewed. Potentially dangerous injuries were present in 7%, minor injuries in 22%, and no injuries in 71% of patients. Sensitivity and specificity of ORR were 78% and 97% for MRI and 30% and 98% for CT. Discrepancies between ORR and EXR occurred in 18% of all patients, or 62% of injured patients, with a substantial number of unreported injuries on CT. CONCLUSIONS: The results indicate that MRI is more appropriate than CT for alert patients presenting after non-self-inflicted strangulation and underline the need for radiologists with specialist knowledge to report these cases in order to add value to both patient care and potential future medico-legal investigations. CLINICAL RELEVANCE STATEMENT: MRI should be preferred over CT for the investigation of strangulation related injuries in alert patients because MRI has a higher accuracy than CT and does not expose this usually young patient population to ionizing radiation. KEY POINTS: • Patients presenting after strangulation are often young women with a history of intimate partner violence while men typically present after assault by an unknown offender. • Expert read-outs of CT and MRI revealed potentially dangerous injuries in one of 14 patients. • MRI has a significantly higher sensitivity than CT and appears to be more appropriate for the diagnostic workup of alert patients after strangulation.

Standards of practice in forensic age estimation with CT of the medial clavicular epiphysis-a systematic review.

The AGFAD (Arbeitsgemeinschaft für Forensische Alterdiagnostik, Study Group on Forensic Age Diagnostics) has published several recommendations regarding both technical aspects of computed tomography (CT) of the medial clavicular epiphysis (MCE) and the process of reading and interpreting the CT images for forensic age estimations (FAE). There are, however, no published recommendations regarding CT scan protocols and no dose reference values for CT of the MCE. The objective of this analysis was to assess adherence to AGFAD recommendations among practitioners of FAE and analyse reported dose-relevant CT scan parameters with the objective of helping to establish evidence-based dose reference values for FAE. A systematic literature search was conducted in PubMed and in Google Scholar with specific MeSH terms to identify original research articles on FAE with CT of the MCE from 1997 to 2022. A total of 48 studies were included. Adherence to AGFAD recommendations among practitioners of FAE is high regarding the use of Schmeling main stages (93%), bone window (79%), ≤ 1 mm CT slices (67%), axial/coronal CT images (65%), and Kellinghaus sub-stages (59%). The reporting of CT technique and CT dose-relevant scan parameters is heterogeneous and often incomplete in the current literature. Considering the success achieved by the AGFAD in creating standards of practice of FAE in living subjects, there is potential for the AGFAD to establish standards for radiation protection in FAE as well.

Constitutional chromothripsis of the APC locus as a cause of genetic predisposition to colon cancer.

PURPOSE: Approximately 20% of patients with clinical familial adenomatous polyposis (FAP) remain unsolved after molecular genetic analysis of the APC and other polyposis genes, suggesting additional pathomechanisms. METHODS: We applied multidimensional genomic analysis employing chromosomal microarray profiling, optical mapping, long-read genome and RNA sequencing combined with FISH and standard PCR of genomic and complementary DNA to decode a patient with an attenuated FAP that had remained unsolved by Sanger sequencing and multigene panel next-generation sequencing for years. RESULTS: We identified a complex 3.9 Mb rearrangement involving 14 fragments from chromosome 5q22.1q22.3 of which three were lost, 1 reinserted into chromosome 5 and 10 inserted into chromosome 10q21.3 in a seemingly random order and orientation thus fulfilling the major criteria of chromothripsis. The rearrangement separates APC promoter 1B from the coding ORF (open reading frame) thus leading to allele-specific downregulation of APC mRNA. The rearrangement also involves three additional genes implicated in the APC-Axin-GSK3B-ß-catenin signalling pathway. CONCLUSIONS: Based on comprehensive genomic analysis, we propose that constitutional chromothripsis dampening APC expression, possibly modified by additional APC-Axin-GSK3B-ß-catenin pathway disruptions, underlies the patient's clinical phenotype. The combinatorial approach we deployed provides a powerful tool set for deciphering unsolved familial polyposis and potentially other tumour syndromes and monogenic diseases.

Interobserver variability of cochlear duct measurements in pediatric cochlear implant candidates.

PURPOSE: The objective of the study was to evaluate the proposed cochlear duct length estimation based on the cochlear 'A value'. Furthermore, we assessed the interobserver variability between radiology and otolaryngology attending physicians and otolaryngology trainees. METHODS: Thirteen pediatric cochlear implant candidates were retrospectively analyzed by three otolaryngology physicians (attending physician, second year, and fourth year trainees) and a radiology attending. The cochlear duct length was calculated based on the formula of Grover et al. The differences in acquired measurements between observers were compared using the Wilcoxon matched signed-rank test. RESULTS: The differences in measurements between the attending otolaryngologist and radiologist were not statistically different, while several significant differences were observed with regard to measurements of attending doctors compared to both residents. In particular, a significant difference between the second year otolaryngology resident and otolaryngology and radiology attending was observed for one side (right ear p = 0.034 and p = 0.012, respectively). Moreover, the fourth year resident calculated significantly different cochlear duct measurements when compared to the attending otolaryngologist (left ear p = 0.014) and radiologist (right ear p = 0.047). Interestingly, differently experienced otolaryngology residents provided significantly different measurements for both ears. CONCLUSIONS: Based on these results, cochlear duct length measurement according to the proposed method may be a reliable and cost-effective method. Indeed, otolaryngology training may be sufficient to provide measurements comparable to radiologists. On the other hand, additional efforts should be invested during otolaryngology training in terms of the evaluation of radiological imaging which may increase the capabilities of otolaryngology residents in this regard.

Multicentric study on surgical information and early safety and performance results with the Bonebridge BCI 602: an active transcutaneous bone conduction hearing implant.

AIM: This European multicentric study aimed to prove safety and performance of the Bonebridge BCI 602 in children and adults suffering from either conductive hearing loss (CHL), mixed hearing loss (MHL), or single-sided sensorineural deafness (SSD). METHODS: 33 patients (13 adults and 10 children with either CHL or MHL and 10 patients with SSD) in three study groups were included. Patients were their own controls (single-subject repeated measures), comparing the unaided or pre-operative to the 3-month post-operative outcomes. Performance was evaluated by sound field thresholds (SF), word recognition scores (WRS) and/or speech reception thresholds in quiet (SRT) and in noise (SNR). Safety was demonstrated with a device-specific surgical questionnaire, adverse event reporting and stable pure-tone measurements. RESULTS: The Bonebridge BCI 602 significantly improved SF thresholds (+ 25.5 dB CHL/MHL/SSD), speech intelligibility in WRS (+ 68.0% CHL/MHL) and SRT in quiet (- 16.5 dB C/MHL) and in noise (- 3.51 dB SNR SSD). Air conduction (AC) and bone conduction (BC) thresholds remained stable over time. All adverse events were resolved, with none unanticipated. Mean audio processor wearing times in hours [h] per day for the CHL/MHL group were ~ 13 h for adults, ~ 11 h for paediatrics and ~ 6 h for the SSD group. The average surgical length was 57 min for the CHL/MHL group and 42 min for the SSD group. The versatility of the BCI 602 (reduced drilling depth and ability to bend the transition for optimal placement) allows for treatment of normal, pre-operated and malformed anatomies. All audiological endpoints were reached. CONCLUSIONS: The Bonebridge BCI 602 significantly improved hearing thresholds and speech understanding. Since implant placement follows the patient's anatomy instead of the shape of the device and the duration of surgery is shorter than with its predecessor, implantation is easier with the BCI 602. Performance and safety were proven for adults and children as well as for the CHL/MHL and SSD indications 3 months post-operatively.

Impact of manual toothbrush design on plaque removal efficacy.

BACKGROUND: Effective dental plaque removal is essential for oral health. Different toothbrush parameters including head-size, filament-diameter and interdent-height and different brushing movements like horizontal, rotating and vertical may affect plaque removal efficacy. The purpose of the study was to examine plaque removal efficacy of different design parameters of manual toothbrushes. METHODS: Eight manual toothbrushes were tested using a validated robot test to examine efficacy of toothbrush on replicated human teeth. Characteristics tested were: (i) head-size, (ii) filament-diameter, (iii) cutting-height, (iv) hardness, (v) interdental-height. Each test ran five times in horizontal, rotating, vertical movements. Simulated Plaque removal was evaluated using automated plaque planimetry: 30 fields/tooth, 13 areas representing buccal, lingual, proximal tooth sites. The Kolmogorov-Smirnov-test was applied to test tooth surface variables for normal distribution of plaque removal values. Parameters were analysed by independent two-sample t-test to assess mean differences. Where null hypothesis of normality was rejected, the Wilcoxon-Mann-Whitney-U-test was used. RESULTS: Plaque removal was significantly better with toothbrush having smaller head-size (compact vs. full-size); smaller filament-diameter (0.12 mm vs. 0.15 mm); larger cutting-height (12 mm vs. 9 mm); softer filaments (0.15 or 0.18 mm vs. 0.23 mm) and greater interdent-height difference (8.5/11 mm vs. 10/11 mm). CONCLUSIONS: Manual brushes allowing filaments free to flex with longer, softer and/or having a difference in filament length overall removed significantly more simulated plaque as compared to more standard flat trim, stiff brushes with shorter, harder bristles and a larger head size. While limited by the in vitro nature of the study design, this indicates that the advances in toothbrush design can further enhance plaque removal.

Price changes and within-class competition of cancer drugs in the USA and Europe: a comparative analysis.

BACKGROUND: Cancer drugs are a major component of pharmaceutical spending in the USA and Europe. The number of approved cancer drugs continues to increase. More new drugs with overlapping mechanisms of action and similar approved indications might be expected to decrease prices within drug classes. We compared patterns of price changes for cancer drugs within the same class in the USA and in two European countries (Germany and Switzerland) with national mechanisms for drug price negotiation. METHODS: For this comparative analysis, we identified cancer drugs approved for the treatment of solid cancers in the USA and Europe (Germany and Switzerland) between Jan 1, 2009, and Dec 31, 2020, using the US Food and Drug Administration's Drugs@FDA database and the European Medicines Agency's publicly available database. We considered cancer drugs as within-class competitors if they were approved for the same indication and had the same biological mechanism. We calculated monthly treatment prices for each drug, median price changes at launch and over time, and differences within and across drug classes. European price data were converted to US dollars by applying the exchange rates on Dec 1, 2020, and prices were adjusted for inflation. Median changes in the drugs' monthly treatment prices at 2 and 4 years after market entry across and within drug classes were also assessed. For the USA, correlations in relative price changes between all pairs of drugs within and across drug classes were calculated with Spearman's rank correlation. FINDINGS: Our study cohort comprised 12 drug classes covering nine indications. With the exception of one drug, increasing prices were observed within and across all drug classes in the USA (median 6·07% [range -3·60 to 33·83] 2 years after market entry, and 15·31% [-4·15 to 54·64] 4 years after market entry). By contrast, in Europe, prices generally decreased over time or did not increase more than inflation (2 years after market entry: -21·01% [range -50·72 to 12·71] in Germany and -1·48% [-26·81 to 1·69] in Switzerland; 4 years after market entry: -25·54% [-51·81 to 11·63] in Germany and -13·02% [-43·83 to 18·31] in Switzerland). In the USA, most prices changes within and across drug classes occurred at the end and beginning of the year (ie, from Dec 1 to Jan 31). In the USA, correlation for price changes was r=0·29 (SD 0·36) for within-class drugs and r=0·28 (0·36) for drugs across drug classes. INTERPRETATION: Competition within classes of cancer drugs generally did not constrain rising prices in the USA. Price negotiations, as practised in Germany or Switzerland, could help address the high prices of cancer drugs in the USA. FUNDING: Swiss Cancer Research Foundation (Krebsforschung Schweiz), Swiss National Science Foundation, and Arnold Ventures.

Cullin 3-Based Ubiquitin Ligases as Master Regulators of Mammalian Cell Differentiation.

Specificity of the ubiquitin proteasome system is controlled by ubiquitin E3 ligases, including their major representatives, the multisubunit cullin-RING ubiquitin (Ub) ligases (CRLs). More than 200 different CRLs are divided into seven families according to their cullin scaffolding proteins (CUL1-7) around which they are assembled. Research over two decades has revealed that different CRL families are specialized to fulfill specific cellular functions. Whereas many CUL1-based CRLs (CRL1s) ubiquitylate cell cycle regulators, CRL4 complexes often associate with chromatin to control DNA metabolism. Based on studies about differentiation programs of mesenchymal stem cells (MSCs), including myogenesis, neurogenesis, chondrogenesis, osteogenesis and adipogenesis, we propose here that CRL3 complexes evolved to fulfill a pivotal role in mammalian cell differentiation.

γδ T cells exhibit multifunctional and protective memory in intestinal tissues.

The study of T cell memory and the target of vaccine design have focused on memory subsumed by T cells bearing the αß T cell receptor. Alternatively, γδ T cells are thought to provide rapid immunity, particularly at mucosal borders. Here, we have shown that a distinct subset of mucosal γδ T cells mounts an immune response to oral Listeria monocytogenes (Lm) infection and leads to the development of multifunctional memory T cells capable of simultaneously producing interferon-γ and interleukin-17A in the murine intestinal mucosa. Challenge infection with oral Lm, but not oral Salmonella or intravenous Lm, induced rapid expansion of memory γδ T cells, suggesting contextual specificity to the priming pathogen. Importantly, memory γδ T cells were able to provide enhanced protection against infection. These findings illustrate that γδ T cells play a role with hallmarks of adaptive immunity in the intestinal mucosa.

From the tyrosine hydroxylase hypothesis of Parkinson's disease to modern strategies: a short historical overview.

A time span of 60 years covers the detection of catecholamines in the brain, their function in movement and correlation to Parkinson's disease (PD). The clinical findings that orally given L-DOPA can alleviate or even prevent akinesia gave great hope for the treatment of PD. Attention focused on the role of tyrosine hydroxylase (TH) as the rate-limiting enzyme in the formation of catecholamines. It became evident that the enzyme driven formation is lowered in PD. Such results could only be obtained from studying human brain samples demonstrating the necessity for human brain banks. Originally, a TH enzyme deficiency was suspected in PD. Studies were conducted on the enzyme properties: its induction and turnover, the complex regulation starting with cofactor requirements as tetrahydrobiopterin and ferrous iron, and the necessity for phosphorylation for activity as well as inhibition by toxins or regulatory feedback inhibition by catecholamines. In the course of time, it became evident that neurodegeneration and cell death of dopaminergic neurons is the actual pathological process and the decrease of TH a cophenomenon. Nevertheless, TH immunochemistry has ever since been a valuable tool to study neuronal pathways, neurodegeneration in various animal models of neurotoxicity and cell cultures, which have been used as well to test potential neuroprotective strategies.

Light contamination in stable isotope-labelled internal peptide standards is frequent and a potential source of false discovery and quantitation error in proteomics.

In mass spectrometry-based proteomics, heavy internal standards are used to validate target peptide detections and to calibrate peptide quantitation. Here, we report light contamination present in heavy labelled synthetic peptides of high isotopic enrichment. Application of such peptides as assay-internal standards potentially compromises the detection and quantitation especially of low abundant cellular peptides. Therefore, it is important to adopt guidelines to prevent false-positive identifications of endogenous light peptides as well as errors in their quantitation from biological samples.

Educating physicians on strong opioids by descriptive versus simulated-experience formats: a randomized controlled trial.

BACKGROUND: Long-term prescriptions of strong opioids for chronic noncancer pain-which are not supported by scientific evidence-suggest miscalibrated risk perceptions among those who prescribe, dispense, and take opioids. Because risk perceptions and behaviors can differ depending on whether people learn about risks through description or experience, we investigated the effects of descriptive versus simulated-experience educative formats on physicians' risk perceptions of strong opioids and their prescription behavior for managing chronic noncancer pain. METHODS: Three hundred general practitioners and 300 pain specialists in Germany-enrolled separately in two independent exploratory randomized controlled online trials-were randomly assigned to either a descriptive format (fact box) or a simulated-experience format (interactive simulation). PRIMARY ENDPOINTS: Objective risk perception (numerical estimates of opioids' benefits and harms), actual prescriptions of seven therapy options for managing chronic pain. SECONDARY ENDPOINT: Implementation of intended prescriptions of seven therapy options for managing chronic pain. RESULTS: Both formats improved the proportion of correct numerical estimates of strong opioids' benefits and harms immediately after intervention, with no notable differences between formats. Compared to description, simulated experience led to significantly lower reported actual prescription rates for strong and/or weak opioids, and was more effective at increasing prescription rates for non-drug-based therapies (e.g., means of opioid reduction) from baseline to follow-up for both general practitioners and pain specialists. Simulated experience also resulted in a higher implementation of intended behavior for some drug-based and non-drug-based therapies. CONCLUSIONS: The two formats, which recruit different cognitive processes, may serve different risk-communication goals: If the goal is to improve exact risk perception, descriptive and simulated-experience formats are likely to be equally suitable. If, however, the goal is to boost less risky prescription habits, simulated experience may be the better choice. TRIAL REGISTRATION: DRKS00020358 (German Clinical Trials Register, first registration: 07/01/2020).