Visualizing chaperone-mediated multistep assembly of the human 20S proteasome

Dedicated assembly factors orchestrate the stepwise production of many molecular machines, including the 28-subunit proteasome core particle (CP) that mediates protein degradation. Here we report cryo-electron microscopy reconstructions of seven recombinant human subcomplexes that visualize all five chaperones and the three active site propeptides across a wide swath of the assembly pathway. Comparison of these chaperone-bound intermediates and a matching mature CP reveals molecular mechanisms determining the order of successive subunit additions, as well as how proteasome subcomplexes and assembly factors structurally adapt upon progressive subunit incorporation to stabilize intermediates, facilitate the formation of subsequent intermediates and ultimately rearrange to coordinate proteolytic activation with gated access to active sites. This work establishes a methodologic approach for structural analysis of multiprotein complex assembly intermediates, illuminates specific functions of assembly factors and reveals conceptual principles underlying human proteasome biogenesis, thus providing an explanation for many previous biochemical and genetic observations.

Mechanism of autocatalytic activation during proteasome assembly

Many large molecular machines are too elaborate to assemble spontaneously and are built through ordered pathways orchestrated by dedicated chaperones. During assembly of the core particle (CP) of the proteasome, where protein degradation occurs, its six active sites are simultaneously activated via cleavage of N-terminal propeptides. Such activation is autocatalytic and coupled to fusion of two half-CP intermediates, which protects cells by preventing activation until enclosure of the active sites within the CP interior. Here we uncover key mechanistic aspects of autocatalytic activation, which proceeds through alignment of the β5 and β2 catalytic triad residues, respectively, with these triads being misaligned before fusion. This mechanism contrasts with most other zymogens, in which catalytic centers are preformed. Our data also clarify the mechanism by which individual subunits can be added in a precise, temporally ordered manner. This work informs two decades-old mysteries in the proteasome field, with broader implications for protease biology and multisubunit complex assembly.

Arthroscopic Treatment Is a Safe and Effective Alternative to Open Treatment for Acute Septic Arthritis of the Native Knee: A Systematic Review

PURPOSE

To compare complication rates, reoperation rates, and subjective outcomes after arthroscopic and open irrigation and debridement for treatment of native knee septic arthritis.

METHODS

Following The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review of the Embase, Cochrane, and PubMed databases was performed. Comparative studies reporting clinical outcomes after arthroscopic versus open treatment for septic arthritis of the native knee in human adults were included. Excluded were case series with <10 patients, inclusion of patients <18 years old, studies on non-native joints, abstract-only publications, and studies without stratification of the involved joint. Two reviewers in duplicate independently performed search and data extraction. The quality of the included studies was assessed with the Methodological Index for Non-Randomized Studies instrument. The mean score among the included studies was 18.2 (range 16-23).

RESULTS

Eleven studies were included, comprising 2,343 knees treated arthroscopically, and 1,595 treated with arthrotomy. Studies reported no differences in erythrocyte sedimentation rate, C-reactive protein, peripheral white blood cells, or symptom chronicity between groups. Nine studies (81.8%) attempted to control for potentially confounding variables in their analyses, and 4 studies (36.4%) reported significant differences in patient characteristics. Reoperation rates ranged from 0% to 50% for arthroscopy and 6% to 71% for arthrotomy. Complication rates ranged from 0% to 39.4% arthroscopically and 0% to 49% for arthrotomy. Superior patient-reported outcomes were achieved after arthroscopy in 2 studies that analyzed subjective outcomes.

CONCLUSIONS

Arthroscopic management of native knee septic arthritis is a safe and effective alternative to open treatment and is associated with comparable complication rates, reoperation rates, hospitalization lengths, readmission rates, and superior patient-reported outcomes compared with open irrigation and debridement.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I, III, and IV studies.

Epidermodysplasia verruciformis-associated eccrine neoplasm: a rare entity with distinctive clinical and histopathologic features

Most tumors are caused by inherited or acquired genetic changes. However, a subset of tumors is driven by viral infection including Kaposi sarcoma, nasopharyngeal carcinoma, and others. Human papillomavirus (HPV) is an especially common cause of epithelial cancers and hyperplasias. Epidermodysplasia verruciformis (EDV) is a rare type of HPV infection with characteristic histopathologic features and a unique spectrum of HPV subtypes. We report here a distinctive form of EDV-associated eccrine neoplasia. Seven tumors from two patients were analyzed and show highly uniform features including multiple clustered clinical lesions, multifocal epidermal origin, eccrine differentiation with close association with the acrosyringium, an anastomosing growth pattern, and a bland monotonous poroid-to-basaloid cytomorphology. Clinical follow-up for one patient has been benign to date. These tumors show strong similarity to two previously reported cases, suggesting that this type of EDV-associated eccrine neoplasia may represent a rare but reproducible form of skin adnexal tumor with distinctive clinicopathologic features.

Innominate artery occlusion: a case study

Aim of the study

The aim of this case report is to evaluate carotid duplex and hemodynamic patterns in an asymptomatic male patient with innominate artery occlusion. Innominate artery occlusion is a rare clinical entity that can lead to a range of cerebrovascular symptoms, including arm claudication, subclavian steal syndrome, and stroke. The case report emphasizes key learning points in diagnosing innominate artery occlusion using imaging and physiological methods.

Case description

A 64-year-old asymptomatic male patient with a history of carotid bruit, hypertension, coronary artery bypass grafting, aortic aneurysm, hyperlipidemia, mild aortic stenosis, long-term tobacco use, and a body mass index of 24 was referred for a carotid ultrasound.

Conclusions

Innominate artery occlusion is a rare condition requiring a comprehensive assessment of collateralization before any intervention is attempted. Considering waveform features such as transient end-diastolic flow reversal and tardus parvus, along with brachial pressures and transcranial Doppler, can assist in evaluating the extent of disease.

Visualizing chaperone-mediated multistep assembly of the human 20S proteasome

Dedicated assembly factors orchestrate stepwise production of many molecular machines, including the 28-subunit proteasome core particle (CP) that mediates protein degradation. Here, we report cryo-EM reconstructions of seven recombinant human subcomplexes that visualize all five chaperones and the three active site propeptides across a wide swath of the assembly pathway. Comparison of these chaperone-bound intermediates and a matching mature CP reveals molecular mechanisms determining the order of successive subunit additions, and how proteasome subcomplexes and assembly factors structurally adapt upon progressive subunit incorporation to stabilize intermediates, facilitate the formation of subsequent intermediates, and ultimately rearrange to coordinate proteolytic activation with gated access to active sites. The structural findings reported here explain many previous biochemical and genetic observations. This work establishes a methodologic approach for structural analysis of multiprotein complex assembly intermediates, illuminates specific functions of assembly factors, and reveals conceptual principles underlying human proteasome biogenesis.

Melanotic PEComa: A Rare But Distinctive Subtype Analyzed in a Series of 7 Cases

Perivascular epithelioid cell neoplasms (PEComas) are tumors of uncertain cell lineage that show a strong female predominance. Their hallmark is the presence of combined smooth muscle and melanocytic differentiation. In most cases, melanocytic differentiation is detectable only by immunohistochemistry, but there are rare reports of PEComa with extensive melanin accumulation (so-called "melanotic PEComa"). Here we report a clinicopathologic series of 7 melanotic PEComas that occurred across a wide patient age range of 21 to 82 years (median: 41 y) and with a wide anatomic distribution, including 2 cases in the pelvis and 1 case each in the gallbladder, cervix, eyelid, epidural space, and femur. All tumors were heavily pigmented and, like conventional PEComas, were composed of variably sized neoplastic cells with voluminous granular, or less commonly clear, cytoplasm with prominent nucleoli. All tumors expressed HMB45 by immunohistochemistry, and 6 of 7 showed nuclear TFE3 expression. Where tested, tumors were uniformly negative for Mart-1/Melan-A, S100, desmin, and smooth muscle actin. Molecular analysis identified TFE3 gene rearrangement in 5 of 7 cases, 4 of which were demonstrated by fluorescence in situ hybridization and one by whole-exome RNA sequencing which revealed a SFPQ::TFE3 fusion. The one tumor negative for TFE3 by immunohistochemistry was found instead to harbor a SFPQ::TFEB fusion, the first reported example to our knowledge of TFEB fusion in a PEComa. Clinical follow-up was available for 6 of 7 patients (median: 2.5 y: range: 0.75 to 7 y). The patient whose tumor harbored SFPQ::TFEB died of metastatic disease 9 months after diagnosis. The other tumors behaved in an indolent fashion: 4 patients were alive without evidence of disease at the most recent follow-up and 1 patient died of an unrelated cancer 4 years after diagnosis of the melanotic PEComa. Our results expand the morphologic and molecular spectrum of melanotic PEComa, and awareness of this rare but distinctive subtype is important to ensure accurate diagnosis within the broader family of heavily pigmented neoplasms.

Rational design of proteasome inhibitors based on the structure of the endogenous inhibitor PI31/Fub1

Proteasome inhibitors are widely used anticancer drugs. The three clinically approved agents are modified small peptides that preferentially target one of the proteasome's three active sites (β5) at physiologic concentrations. In addition to these drugs, there is also an endogenous proteasome inhibitor, PI31/Fub1, that enters the proteasome's interior to simultaneously yet specifically inhibit all three active sites. Here, we have used PI31's evolutionarily optimized inhibitory mechanisms to develop a suite of potent and specific β2 inhibitors. The lead compound strongly inhibited growth of multiple myeloma cells as a standalone agent, indicating the compound's cell permeability and establishing β2 as a potential therapeutic target in multiple myeloma. The lead compound also showed strong synergy with the existing β5 inhibitor bortezomib; such combination therapies might help with existing challenges of resistance and severe side effects. These results represent an effective method for rational structure-guided development of proteasome inhibitors.

Structure of the preholoproteasome reveals late steps in proteasome core particle biogenesis

Assembly of the proteasome's core particle (CP), a barrel-shaped chamber of four stacked rings, requires five chaperones and five subunit propeptides. Fusion of two half-CP precursors yields a complete structure but remains immature until active site maturation. Here, using Saccharomyces cerevisiae, we report a high-resolution cryogenic electron microscopy structure of preholoproteasome, a post-fusion assembly intermediate. Our data reveal how CP midline-spanning interactions induce local changes in structure, facilitating maturation. Unexpectedly, we find that cleavage may not be sufficient for propeptide release, as residual interactions with chaperones such as Ump1 hold them in place. We evaluated previous models proposing that dynamic conformational changes in chaperones drive CP fusion and autocatalytic activation by comparing preholoproteasome to pre-fusion intermediates. Instead, the data suggest a scaffolding role for the chaperones Ump1 and Pba1/Pba2. Our data clarify key aspects of CP assembly, suggest that undiscovered mechanisms exist to explain CP fusion/activation, and have relevance for diseases of defective CP biogenesis.

Deep-penetrating-nevus-like melanoma arising in patients with familial adenomatous polyposis syndrome

Deep penetrating nevi (DPN) are uncommon but distinctive melanocytic neoplasms that show an epithelioid to spindle cell morphology, prominent pigmentation with melanophages, and a plexiform growth pattern. Molecularly, most DPN are thought to be characterized by dual activation of the mitogen-activated protein kinase and the wingless-related integration site (Wnt) pathways, the latter being most commonly driven by activating β-catenin mutations. DPN-like melanomas are very rare but can be recognized through their overlapping morphologic and architectural features with DPN. Familial adenomatous polyposis (FAP) is a hereditary cancer predisposition syndrome associated with multiple tumor types including colorectal carcinoma and desmoid fibromatosis. Like DPN, FAP is also driven by activation of the Wnt pathway, most commonly through loss of function mutations in APC, which is a major negative regulator of β-catenin. Here we report two cases of DPN-like melanoma arising in FAP patients. While the small number of cases precludes definitive establishment of an etiologic link between these entities, the shared molecular pathogenesis of DPN-like lesions and FAP suggests that FAP patients may be at increased risk for this rare subtype of melanoma.

A Novel Fusion Partner, SP100, Drives Nuclear Dot Localization of ALK in Epithelioid Fibrous Histiocytoma

ABSTRACT

Epithelioid fibrous histiocytoma (EFH) is a distinctive benign cutaneous neoplasm composed of uniform epithelioid cells, often with binucleated cells. EFH are characterized by the presence of anaplastic lymphoma kinase (ALK) gene rearrangements with a variety of binding partners. These rearrangements result in the overexpression of ALK, which can be detected using immunohistochemistry. Cytoplasmic ALK expression is by far the most common pattern encountered. Here, we describe a case of EFH with a distinctive intranuclear dot-like ALK expression pattern. Subsequent next-generation DNA sequencing revealed a novel SP100::ALK gene fusion. Speckled protein-100 (SP100) is a constituent of nuclear dots, also known as promyelocytic leukemia bodies, which are still poorly understood membraneless subnuclear structures. Thus, this novel ALK fusion partner seems to explain this distinctive pattern of ALK localization. We examined ALK expression patterns in 11 other cases of EFH, but all showed typical cytoplasmic localization. This study expands the morphologic and molecular spectrum of EFH, provides a dramatic illustration of the ability of fusion partners to control protein localization, and implies that tumorigenic ALK signaling may occur at a variety of subcellular locations.

D-SPIN constructs gene regulatory network models from multiplexed scRNA-seq data revealing organizing principles of cellular perturbation response

Gene regulatory networks within cells modulate the expression of the genome in response to signals and changing environmental conditions. Reconstructions of gene regulatory networks can reveal the information processing and control principles used by cells to maintain homeostasis and execute cell-state transitions. Here, we introduce a computational framework, D-SPIN, that generates quantitative models of gene-regulatory networks from single-cell mRNA-seq data sets collected across thousands of distinct perturbation conditions. D-SPIN models the cell as a collection of interacting gene-expression programs, and constructs a probabilistic model to infer regulatory interactions between gene-expression programs and external perturbations. Using large Perturb-seq and drug-response datasets, we demonstrate that D-SPIN models reveal the organization of cellular pathways, sub-functions of macromolecular complexes, and the logic of cellular regulation of transcription, translation, metabolism, and protein degradation in response to gene knockdown perturbations. D-SPIN can also be applied to dissect drug response mechanisms in heterogeneous cell populations, elucidating how combinations of immunomodulatory drugs can induce novel cell states through additive recruitment of gene expression programs. D-SPIN provides a computational framework for constructing interpretable models of gene-regulatory networks to reveal principles of cellular information processing and physiological control.

Clear cell tumor with melanocytic differentiation and MITF::CREM translocation

In addition to melanoma, a large and diverse family of tumors shows melanocytic differentiation. The best characterized member of this family is clear cell sarcoma, which is characterized by EWSR1::ATF1 and EWSR1::CREB1 fusions. These fusions drive the transcription of MITF, the master regulator of melanocytic differentiation. Clear cell tumor with melanocytic differentiation and MITF::CREM translocation is a recently described tumor with some similarities to clear cell sarcoma. However, only a single case has been reported. Here, we describe a second molecularly proven case that arose on the scalp of a newborn baby. In contrast to the prior reported case, the current case showed predominantly high-grade cytomorphologic features with only focal clear cell areas. Similar to the prior case, the tumor showed immunohistochemical evidence of neural crest origin/differentiation with prominent melanocytic differentiation. The fusion breakpoints were also similar and preserved the transcriptional activation domain of CREM, suggesting that CREM hyperactivity is a major feature of this tumor type. The current tumor showed a short-interval recurrence. These results expand the clinical and pathologic spectrum of this potentially new entity.

An evidence-based approach to provide essential and desirable components to develop surveys on Sudden Unexpected Death in Epilepsy (SUDEP) for doctors: A focused review

Sudden Unexpected Death in Epilepsy (SUDEP) is a major concern for people with epilepsy, their families, their care givers, and medical professionals. There is inconsistency in the SUDEP counselling doctors provide, compared to what is recommended in clinical guidelines. Numerous national and international surveys have highlighted how epilepsy professionals, usually doctors, deliver SUDEP risk counselling, particularly, when they deliver it and to whom. These surveys help understand the unmet need, develop suitable strategies, and raise awareness among clinicians with the eventual goal to reduce SUDEPs. However, there is no standardised survey or essential set of questions identified that can be used to evaluate SUDEP counselling practice globally. This focused review analyses the content of all published SUDEP counselling surveys for medical professionals (n=16) to date covering over 4000 doctors across over 30 countries and five continents. It identifies 36 question themes across three topics. The questions are then reviewed by an expert focus group of SUDEP communication experts including three doctors, an expert statistician and SUDEP Action, an UK based charity specialising in epilepsy deaths with a pre-set criterion. The review and focus group provide ten essential questions that should be included in all future surveys inquiring on SUDEP counselling. They could be used to evaluate current practice and compare findings over time, between services, across countries and between professional groups. They are provided as a template to download and use. The review also explores if there is a continued need in future for similar surveys to justify this activity.

Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

DUB-le vision: snapshots of the proteasome during substrate processing

Covalent modification by the small protein ubiquitin can target proteins for destruction by the proteasome, but the ubiquitin signal itself is recycled. Surprisingly, proteasomes contain three different deubiquitinating enzymes (DUBs). Recent work by Zhang and Zou et al. reveals how one of these enzymes, Usp14, regulates, and is regulated by, the proteasome.

MAML2 Gene Rearrangement Occurs in Nearly All Hidradenomas: A Reappraisal in a Series of 20 Cases

ABSTRACT

Hidradenoma is a benign cutaneous adnexal neoplasm that occurs across a wide age range and at a variety of anatomic sites. Its most characteristic morphologic feature is the presence of diverse cell types including squamoid, clear, plasmacytoid, and mucinous cells. Hidradenoma is morphologically and molecularly similar to mucoepidermoid carcinoma, and both tumors are characterized by recurrent CRTC1-MAML2 cytogenetic translocations. Previous studies have suggested that approximately half of hidradenomas possess this translocation. This finding raised the question of whether translocation-negative hidradenomas might have an alternate molecular basis. Here, we sought to reevaluate the frequency of MAML2 translocation in hidradenoma in a series of 20 cases. We find that 90% show evidence of MAML2 translocation, suggesting that this genetic event is a nearly invariant feature of hidradenoma. These results inform our molecular understanding of this tumor and may be useful in challenging cases to distinguish hidradenoma from its histologic mimics.

Melanoma arising in extracutaneous cellular blue nevus: report of two cases with comparison to cutaneous counterparts and uveal melanoma

AIMS

Blue nevi are benign melanocytic lesions that typically occur in the dermis. Melanoma arising in blue nevus is rare and shows a molecular profile distinct from conventional forms of cutaneous melanoma and more similar to uveal melanoma and central nervous system (CNS) melanocytomas. In contrast to conventional cutaneous melanoma, these tumor types typically show activating driver mutations in GNAQ or GNA11, a low mutational burden without evidence of a UV signature, and a reproducible pattern of chromosomal copy number changes. Blue nevi can also occur at extracutaneous sites. Here we report two cases of melanoma arising in extracutaneous blue nevus and compare their molecular features to cohorts of melanoma arising in cutaneous blue nevus (5 patients) and uveal melanoma (6 patients).

METHODS AND RESULTS

We describe the clinical, histomorphologic, immunohistochemical, and molecular findings in these two cases of melanoma arising in extracutaneous blue nevus. We compare their molecular profiles to melanomas arising in cutaneous blue nevus and uveal melanoma using a targeted next-generation DNA sequencing platform and find striking similarities between all three groups.

CONCLUSIONS

The close relationship between blue nevus-associated melanomas, regardless of their anatomic site, supports and validates the concept of melanoma arising in extracutaneous blue nevus and suggests that the two groups share common pathogenic mechanisms. The similarity of both groups to uveal melanoma in turn supports the close relationship between blue nevus-associated melanoma, uveal melanoma, and CNS melanocytoma, and their distinction from conventional UV-associated melanoma. These findings have important implications for prognosis and therapy.

Asking questions can help: development and preliminary evaluation of a question prompt list for patients living with Heart Failure

Funding Acknowledgements

Type of funding sources: None.

Background

Discussing disease trajectories with patients living with chronic illnesses is recommended in guidelines worldwide and Heart Failure [HF] is no different. Discussions are centered around day-to-day disease management and less on illness trajectory including prognosis, symptoms, treatment options, preferences, and advanced care planning. Lack of open communication is common leading to prolonged suffering and unnecessary admissions [1] and can be improved when patients are able to initiate discussions, ask questions that are of concern to them, and engage in healthcare decision making [2,3].

A range of approaches have been employed to promote patient participation and empowerment. One such approach is the use of Question Prompt Lists [QPL]. Studies show that QPLs are linked to more questions asked, increased satisfaction, and reduced unmet information needs [3,4]. Despite this, they are less commonly used in non-oncology contexts and not available in Lebanon. Health system differences and cultural factors may influence content and impact of QPLs and as such cross-cultural adaptation is essential [5]. As the need for disclosure can vary among cultures, examining QPLs through an anthropological lens is imperative.

Purpose

To develop a culturally sensitive QPL designed to improve communication about HF illness trajectory.

Methods

A review of literature on HF QPLs was done. To address cultural and country specific needs, studies on HF from Lebanon and the Middle East were reviewed. This comprised the initial draft of a QPL that included context specific challenges and concerns. A Delphi survey inviting an interdisciplinary team of healthcare providers caring for HF patients was used to seek expert consensus regarding the draft. Sixteen experts rated each question for relevance, using a Likert scale from 0 to 4, clarity, and need to rephrase and suggested additional questions. Ratings were analyzed to determine the level of consensus. Questions that received less than 80% favorable answers [Very Relevant/Relevant and/or more than 20% indicated lack of clarity or the need to rephrase] were discussed in the second round of Delphi. Experts met and reviewed the comments provided on some questions and questions that were rated unfavorably, suggested for deletion, as well as those added by the panelists. Clarity of questions and suggestions for wording improvements was ensured.

Results

During the second round of Delphi, 12 questions were rephrased, one was dropped, and one was added. A final QPL of 42 questions and 6 categories was reached.

Conclusion

This is the first step of more research work that will aim at developing Arabic QPLs in the Middle East. The immediate next step would be repeating the Survey with patients, caregivers, and HF providers. Data will be analyzed using central tendency and levels of dispersion to assess consensus. The final QPLs will be translated to Arabic, culturally validated, and pilot tested in Lebanon.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Pasteurella multocida Bacteremia Secondary to Peritoneal Dialysis Associated Peritonitis: A Case Report and Literature Review

We report the fiftieth case in the literature of Pasteurella species peritoneal dialysis (PD)-related peritonitis and the third reported case of Pasteurella multocida bacteremia associated with PD-related peritonitis. Our review provides the most up-to-date collection of all fifty reported cases of PD-related peritonitis caused by Pasteurella species. A 77-year-old Caucasian male with a past medical history significant for new-onset left-ventricular systolic heart failure, severe mitral valve regurgitation, and end-stage renal disease on PD for six months presented to the emergency department with a one-week cloudy peritoneal effluent and intermittent abdominal pain. Pasteurella multocida was isolated from blood cultures and peritoneal fluid cultures. The patient was treated with intravenous piperacillin-tazobactam and intraperitoneal cefepime. The PD catheter was not removed or exchanged. A repeat blood culture on the third hospital day was negative. His hospital course was complicated by cardiogenic shock, atrial fibrillation, and gastrointestinal bleeding, and his goals of care changed to focus on comfort measures. This case report and literature review provide a resource for healthcare providers who may encounter this infection in the future. This case also serves as a reminder of the challenges of PD in patients at risk of acquired zoonotic infections from their pets. Based on the reviewed three cases of Pasteurella multocida bacteremia associated with PD-related peritonitis, blood cultures may be a prudent option for patients presenting with peritoneal dialysis associated peritonitis to ensure that concurrent bacteremia is not overlooked.

Chaperone-mediated assembly of the proteasome core particle - recent developments and structural insights

Much of cellular activity is mediated by large multisubunit complexes. However, many of these complexes are too complicated to assemble spontaneously. Instead, their biogenesis is facilitated by dedicated chaperone proteins, which are themselves excluded from the final product. This is the case for the proteasome, a ubiquitous and highly conserved cellular regulator that mediates most selective intracellular protein degradation in eukaryotes. The proteasome consists of two subcomplexes: the core particle (CP), where proteolysis occurs, and the regulatory particle (RP), which controls substrate access to the CP. Ten chaperones function in proteasome biogenesis. Here, we review the pathway of CP biogenesis, which requires five of these chaperones and proceeds through a highly ordered multistep pathway. We focus on recent advances in our understanding of CP assembly, with an emphasis on structural insights. This pathway of CP biogenesis represents one of the most dramatic examples of chaperone-mediated assembly and provides a paradigm for understanding how large multisubunit complexes can be produced.

Targeted protein degradation: from small molecules to complex organelles-a Keystone Symposia report

Targeted protein degradation is critical for proper cellular function and development. Protein degradation pathways, such as the ubiquitin proteasomes system, autophagy, and endosome-lysosome pathway, must be tightly regulated to ensure proper elimination of misfolded and aggregated proteins and regulate changing protein levels during cellular differentiation, while ensuring that normal proteins remain unscathed. Protein degradation pathways have also garnered interest as a means to selectively eliminate target proteins that may be difficult to inhibit via other mechanisms. On June 7 and 8, 2021, several experts in protein degradation pathways met virtually for the Keystone eSymposium "Targeting protein degradation: from small molecules to complex organelles." The event brought together researchers working in different protein degradation pathways in an effort to begin to develop a holistic, integrated vision of protein degradation that incorporates all the major pathways to understand how changes in them can lead to disease pathology and, alternatively, how they can be leveraged for novel therapeutics.

Mechanism of Proteasome Gate Modulation by Assembly Chaperones Pba1 and Pba2

The active sites of the proteasome are housed within its central core particle (CP), a barrel-shaped chamber of four stacked heptameric rings, and access of substrates to the CP interior is mediated by gates at either axial end. These gates are constitutively closed and may be opened by the regulatory particle (RP), which binds the CP and facilitates substrate degradation. We recently showed that the heterodimeric CP assembly chaperones Pba1/2 also mediate gate opening through an unexpected structural arrangement that facilitates the insertion of the N terminus of Pba1 into the CP interior; however, the full mechanism of Pba1/2-mediated gate opening is unclear. Here, we report a detailed analysis of CP gate modulation by Pba1/2. The clustering of key residues at the interface between neighboring α-subunits is a critical feature of RP-mediated gate opening, and we find that Pba1/2 recapitulate this strategy. Unlike RP, which inserts at six α-subunit interfaces, Pba1/2 insert at only two α-subunit interfaces. Nevertheless, Pba1/2 are able to regulate six of the seven interfacial clusters, largely through direct interactions. The N terminus of Pba1 also physically interacts with the center of the gate, disrupting the intersubunit contacts that maintain the closed state. This novel mechanism of gate modulation appears to be unique to Pba1/2 and therefore likely occurs only during proteasome assembly. Our data suggest that release of Pba1/2 at the conclusion of assembly is what allows the nascent CP to assume its mature gate conformation, which is primarily closed, until activated by RP.

Trends in upper extremity injuries presenting to emergency departments during the COVID-19 pandemic

Introduction

Methods

Results

Conclusion

Level of evidence

The impact of COVID-19 on epilepsy care: Perspectives from UK healthcare workers

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We surveyed UK healthcare workers (HCWs) involved in the care of people with epilepsy.

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During the pandemic, 70% of respondents held most consultations remotely.

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HCWs experienced increased mental strain and concern for colleagues/family members.

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HCWs reported being less confident in diagnosing epilepsy remotely.

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Clinicians were more reluctant to withdraw seizure medications during the pandemic.

The COVID-19 pandemic has created an immense pressure on healthcare providers, resulting in a shift to remote consultations and the redeployment of healthcare workers (HCWs). We present survey data from the United Kingdom (UK) HCWs to outline how changes in healthcare provision impact clinicians' wellbeing and ability to provide adequate care. We designed an online survey to gather the experiences of HCWs providing care to people with epilepsy. We received seventy-nine responses from UK-based HCWs, of whom 43% reported an impact on their mental health. Changes to service delivery have resulted in 71% of clinicians performing > 75% of their consultations remotely. Diagnosing and treating epilepsy has changed, with a fifth of respondents being significantly less confident in diagnosing epilepsy. Ultimately, these results show that COVID-19 has had an overall negative impact on HCWs and their ability to provide epilepsy care. These results must be considered when reorganizing health services to ensure optimal outcomes for people with epilepsy.

1288 Colorectal Cancer Surgery Service Provision During The COVID-19 Pandemic: An Assessment of a Single Trust

Aim

Post-operative pulmonary complications in perioperative SARS-CoV-2 infection are associated with significant morbidity and mortality. To maintain a safe cancer service, the Countess of Chester Hospital adopted “Cold-site” operating and maintained ERAS principles for patients undergoing elective colorectal cancer surgery during the pandemic. A comparative assessment of service was undertaken for benchmarking purposes.

Method

A comparative retrospective audit was undertaken of consecutive patients undergoing elective colorectal cancer surgery from June to November 2019 and compared to June to November 2020. The Somerset Cancer Registry and electronic medical case records were used to obtain the dataset. Outcomes measured were approach to surgery; stoma rate; length of stay; level of care required; post-operative complications (&gt;Clavien-Dindo 2) and survival at 30 days. Mann-Whitney U test and Chi-squared were used for analysis.

Results

There were 33 and 24 elective colorectal cancer operations in 2019 and 2020 respectively. There was no difference in the median age (64:69; p = 0.3) or ASA grade (p = 0.9). The median length of stay was 5 and 4 days respectively (p = 0.3). There was a 32.2% reduction in laparoscopic approach to surgery in 2020 (69.7% vs 37.5%; p = 0.02). There was no difference in the stoma rate (p = 0.9), post-operative complication rate (p = 0.7), ITU admission rate (p = 0.3), length of ITU stay (p = 0.6) and 30-day mortality rates (p = 0.4).

Conclusions

“Cold-site” operating allows robust ERAS care to be adopted to ensure comparative outcomes for patients undergoing colorectal cancer surgery and was associated with a non-significant trend to shorter hospital stay during the COVID-19 pandemic.

Risk Factors Associated with the Clinical Outcomes of COVID-19 and Its Variants in the Context of Cytokine Storm and Therapeutics/Vaccine Development Challenges

The recent appearance of SARS-CoV-2 is responsible for the ongoing coronavirus disease 2019 (COVID-19) pandemic and has brought to light the importance of understanding this highly pathogenic agent to prevent future pandemics. This virus is from the same single-stranded positive-sense RNA family, Coronaviridae, as two other epidemic-causing viruses, SARS-CoV-1 and MERS-CoV. During this pandemic, one crucial focus highlighted by WHO has been to understand the risk factors that may contribute to disease severity and predict COVID-19 outcomes. In doing so, it is imperative to understand the virology of SARS-CoV-2 and the immunological response eliciting the clinical manifestation and progression of COVID-19. In this review, we provide clinical data-based analyses of how multiple risk factors (such as sex, race, HLA genotypes, blood groups, vitamin D deficiency, obesity, smoking, and asthma) contribute to the inflammatory overactivation and cytokine storm (frequently seen in COVID-19 patients) with a focus on the IL-6 pathway. We also draw comparisons to the virulence and pathophysiology of SARS and MERS to establish parallels in immune response and discuss the potential for therapeutic approaches that may limit disease progression in patients with higher risk profiles than others. Moreover, we cover the latest information on approved or upcoming COVID-19 vaccines. This paper also provides perspective on emerging variants and associated opportunistic infections such as black molds and fungus that have added to mortality in some parts of the world, such as India. This compilation of existing COVID-19 studies and data will provide an excellent referencing tool for the research, clinical, and public health communities.

THE VALUE OF A REGIONAL 'LIVING' COVID-19 REGISTRY AND THE CHALLENGES OF KEEPING IT ALIVE

BACKGROUND

The availability of accurate, reliable, and timely clinical data is crucial for clinicians, researchers, and policymakers so that they can respond effectively to emerging public health threats. This was typified by the recent SARS-CoV-2 pandemic and the critical knowledge and data gaps associated with novel Coronavirus 2019 disease (COVID-19).We sought to create an adaptive, living data mart containing detailed clinical, epidemiologic, and outcome data from COVID-19 patients in our healthcare system. If successful, the approach could then be used for any future outbreak or disease.

METHODS

From 3/13/2020 onward, demographics, comorbidities, outpatient medications, along with 75 laboratory, 2 imaging, 19 therapeutic, and 4 outcome-related parameters, were manually extracted from the electronic medical record (EMR) of SARS-CoV-2 positive patients. These parameters were entered on a registry featuring calculation, graphing tools, pivot tables, and a macro programming language. Initially, two internal medicine residents populated the database, then professional data abstractors populated the registry. Clinical parameters were developed with input from infectious diseases and critical care physicians and using a modified COVID-19 worksheet from the U.S. Centers for Disease Control and Prevention (CDC). Registry contents were migrated to a browser-based, metadata-driven electronic data capture software platform. Eventually, we developed queries and used various business intelligence (BI) tools which enabled us to semi-automate data ingestion of 147 clinical and outcome parameters from the EMR, via a large U.S. hospital-based, service-level, all-payer database. Statistics were performed in R and Minitab.

RESULTS

From March 13, 2020 to May 17, 2021, 549,691 SARS-CoV-2 test results on 236,144 distinct patients, along with location, admission status, and other epidemiologic details are stored on the cloud-based BI platform. From March 2020 until May 2021, extraction of clinical-epidemiologic parameter had to be performed manually. Of those, 543 have had >/=75 parameters fully entered in the registry. Ten clinical characteristics were significantly associated with the need for hospital admission. Only one characteristic was associated with a need for ICU admission. Use of supplemental oxygen, vasopressors and outpatient statin were associated with increased mortality.Initially, 0.5hrs -1.5 hours per patient chart (approximately 450-575 person hours) were required to manually extract the parameters and populate the registry. As of May 17, 2021, semi-automated data ingestion from the U.S. hospital all-payer database, employing user-defined queries, was implemented. That process can ingest and populate the registry with 147 clinical, epidemiologic, and outcome parameters at a rate of 2 hours per 100 patient charts.

CONCLUSION

A living COVID-19 registry represents a mechanism to facilitate optimal sharing of data between providers, consumers, health information networks, and health plans through technology-enabled, secure-access electronic health information. Our approach also involves a diversity of new roles in the field, such as using residents, staff, and the quality department, in addition to professional data extractors and the health informatics team.Initially, due to the overwhelming number of infections that continues to accelerate, and the labor/time intense nature of the project, only a small fraction of all patients with COVID-19 had all parameters entered in the registry. Therefore, this report also offers lessons learned and discusses sustainability issues, should others wish to establish a registry. It also highlights the registry's local and broader public health significance. Beginning in June 2021, whole-genome sequencing results such as lineages harboring important viral mutations, or variants of concern will be linked to the clinical meta-data.

Symptom Management Among Cancer Survivors: Randomized Pilot Intervention Trial of Heart Rate Variability Biofeedback

Chronic cancer-related symptoms (stress, fatigue, pain, depression, insomnia) may be linked with sympathetic nervous system over-activation and autonomic imbalance. Decreased heart rate variability (HRV) is an indicator of autonomic dysregulation that is commonly observed among cancer survivors. HRV biofeedback (HRVB) training induces HRV coherence, which maximizes HRV and facilitates autonomic and cardiorespiratory homeostasis. This randomized, wait-list-controlled, pilot intervention trial tested the hypothesis that HRVB can improve HRV coherence and alleviate cancer-related symptoms. The intervention group (n = 17) received 4-6 weekly HRVB training sessions until participants demonstrated skill acquisition. Controls (n = 17) received usual care. Outcomes assessed at baseline and follow-up included 15-min HRV recordings (HRV Coherence Ratio), and symptoms of: stress, distress, post-traumatic stress disorder (PTSD), pain, depression, fatigue, and sleep disturbance. Linear mixed models for repeated measures were used to assess Group-by-Time interactions, pre- versus post-treatment differences in mean symptom scores, and group differences at follow-up. Mean HRV Coherence Ratios (± standard error) improved in the HRVB group at follow-up (baseline: 0.37 ± 0.05, post-intervention: 0.84 ± 0.18, p = 0.01), indicating intervention validity. Statistically significant Group-by-Time interactions indicated treatment-related improvements in HRV Coherence Ratios (p = 0.03, Pre-vs. post-treatment effect size [Cohen's d]: 0.98), sleep symptoms (p = 0.001, d = 1.19), and sleep-related daytime impairment (p = 0.005, d = 0.86). Relative to controls, the intervention group experienced trends toward improvements in stress, distress, fatigue, PTSD, and depression, although no other statistically significant Group-by-Time interactions were observed. This pilot intervention found that HRVB training reduced symptoms of sleep disturbance among cancer survivors. Larger-scale interventions are warranted to further evaluate the role of HRVB for managing symptoms in this population. Registration: NCT03692624 www.clinicaltrials.gov.

Structures of chaperone-associated assembly intermediates reveal coordinated mechanisms of proteasome biogenesis

The proteasome mediates most selective protein degradation. Proteolysis occurs within the 20S core particle (CP), a barrel-shaped chamber with an α₇β₇β₇α₇ configuration. CP biogenesis proceeds through an ordered multistep pathway requiring five chaperones, Pba1-4 and Ump1. Using Saccharomyces cerevisiae, we report high-resolution structures of CP assembly intermediates by cryogenic-electron microscopy. The first structure corresponds to the 13S particle, which consists of a complete α-ring, partial β-ring (β2-4), Ump1 and Pba1/2. The second structure contains two additional subunits (β5-6) and represents a later pre-15S intermediate. These structures reveal the architecture and positions of Ump1 and β2/β5 propeptides, with important implications for their functions. Unexpectedly, Pba1's N terminus extends through an open CP pore, accessing the CP interior to contact Ump1 and the β5 propeptide. These results reveal how the coordinated activity of Ump1, Pba1 and the active site propeptides orchestrate key aspects of CP assembly.

Reg1 and Snf1 regulate stress-induced relocalization of protein phosphatase-1 to cytoplasmic granules

The compartmentalization of cellular function is achieved largely through the existence of membrane-bound organelles. However, recent work suggests a novel mechanism of compartmentalization mediated by membraneless structures that have liquid droplet-like properties and arise through phase separation. Cytoplasmic stress granules (SGs) are the best characterized and are induced by various stressors including arsenite, heat shock, and glucose deprivation. Current models suggest that SGs play an important role in protein homeostasis by mediating reversible translation attenuation. Protein phosphatase-1 (PP1) is a central cellular regulator responsible for most serine/threonine dephosphorylation. Here, we show that upon arsenite stress, PP1's catalytic subunit Glc7 relocalizes to punctate cytoplasmic granules. This altered localization requires PP1's recently described maturation pathway mediated by the multifunctional ATPase Cdc48 and PP1's regulatory subunit Ypi1. Glc7 relocalization is mediated by its regulatory subunit Reg1 and its target Snf1, the AMP-dependent protein kinase. Surprisingly, Glc7 granules are highly specific to arsenite and appear distinct from canonical SGs. Arsenite induces potent translational inhibition, and translational recovery is strongly dependent on Glc7, but independent of Glc7's well-established role in regulating eIF2α. These results suggest a novel form of stress-induced cytoplasmic granule and a new mode of translational control by Glc7.

Clear cell tumor with melanocytic differentiation and MITF-CREM translocation: a novel entity similar to clear cell sarcoma

The presence of melanocytic differentiation in tumors of non-melanocyte origin is uncommon and is typically associated with the overexpression of MITF, the master regulator of melanin synthesis, or another member of the MIT/TFE3 family. In clear cell sarcoma, the presence of either an EWSR1-ATF1 or EWSR1-CREB1 translocation-derived fusion protein is thought to drive melanocytic differentiation by directly stimulating the expression of MITF. Here, we describe a clear cell neoplasm with melanocytic differentiation that is characterized by a novel MITF-CREM gene fusion. CREM is the third member of the ATF1/CREB1/CREM family, and the nature of the MITF-CREM fusion appears analogous to the EWSR1-ATF1 and EWSR1-CREB1 fusions. Thus, this MITF-CREM-rearranged clear cell tumor represents a novel entity with morphologic, immunohistochemical, and molecular similarity to clear cell sarcoma.

Utility of YAP1 and NUT immunohistochemistry in the diagnosis of porocarcinoma

BACKGROUND

Porocarcinoma is the malignant counterpart of poroma, a benign tumor derived from the eccrine or apocrine units. In contrast to poroma, porocarcinoma is rare and its diagnosis may be challenging. Recent work has identified YAP1-associated gene fusions in most poromas, and a subset of porocarcinomas. These included YAP1-MAML2 and YAP1-NUTM1, the latter being enriched in porocarcinomas over poromas.

METHODS

We studied YAP1 C-terminus and NUT immunohistochemistry in a cohort of 12 porocarcinomas, 10 poromas, 10 squamous cell carcinomas, and 6 hidradenocarcinomas.

RESULTS

Seven of 12 (58%) porocarcinomas showed loss of YAP1 C-terminus expression, consistent with a YAP1 fusion. Of these seven, five showed NUT positivity, implying the presence of the YAP1-NUTM1 fusion. One of 12 (8%) cases showed NUT positivity, but retention of YAP1 C-terminus expression, consistent with a non-YAP1 NUT-associated fusion. Eight of 10 (80%) poromas showed loss of YAP1 C-terminus expression and negative NUT staining, consistent with non-NUT YAP1 fusions. All squamous cell carcinomas and hidradenocarcinomas retained YAP1 C-terminus expression and were negative for NUT.

CONCLUSION

YAP1 C-terminus and NUT immunohistochemistry may be helpful in the diagnosis of porocarcinoma, with the combination of YAP1 C-terminus loss and NUT positivity being particularly informative.

Temporal, Spatial, and Epidemiologic Relationships of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Gene Cycle Thresholds: A Pragmatic Ambi-directional Observation

Prospective serial sampling of 70 patients revealed clinically relevant cycle thresholds (Ct) occurred 9, 26, and 36 days after symptom onset. Race, gender, or corticosteroids did not appear to influence RNA-positivity. Retrospective analysis of 180 patients revealed that initial Ct did not correlate with requirement for admission or intensive care

A phase 1b/2 study of duvelisib in combination with FCR (DFCR) for frontline therapy for younger CLL patients

Fludarabine, cyclophosphamide, and rituximab (FCR) is highly effective initial therapy for younger patients with chronic lymphocytic leukemia (CLL); however, most eventually relapse. Duvelisib is a delta/gamma PI3K inhibitor approved for relapsed/refractory CLL. We conducted an investigator-initiated, phase 1b/2 study of duvelisib + FCR (DFCR) as initial treatment for CLL patients aged ≤65. A standard 3 + 3 design included two dose levels of duvelisib (25 mg qd and 25 mg bid). Duvelisib was given for 1 week, then with standard FCR added for up to six 28-day cycles, then up to 2 years of duvelisib maintenance. Thirty-two patients were enrolled. The phase 2 dose of duvelisib was identified as 25 mg bid. Hematologic toxicity was common, and all-grade non-hematologic toxicities included transaminitis (28%), febrile neutropenia (22%), pneumonia (19%), and colitis (6%). The best overall response rate by ITT was 88% (56% CR/CRi and 32% PR). The best rate of bone marrow undetectable minimal residual disease (BM-uMRD) by ITT was 66%. The rate of CR with BM-uMRD at end of combination treatment (primary endpoint) was 25%. Three-year PFS and OS are 73 and 93%, respectively. DFCR is active as initial therapy of younger CLL patients. Immune-mediated and infectious toxicities occurred and required active management.

Thiol-based direct threat sensing by the stress-activated protein kinase Hog1

The yeast stress-activated protein kinase Hog1 is best known for its role in mediating the response to osmotic stress, but it is also activated by various mechanistically distinct environmental stressors, including heat shock, endoplasmic reticulum stress, and arsenic. In the osmotic stress response, the signal is sensed upstream and relayed to Hog1 through a kinase cascade. Here, we identified a mode of Hog1 function whereby Hog1 senses arsenic through a direct physical interaction that requires three conserved cysteine residues located adjacent to the catalytic loop. These residues were essential for Hog1-mediated protection against arsenic, were dispensable for the response to osmotic stress, and promoted the nuclear localization of Hog1 upon exposure of cells to arsenic. Hog1 promoted arsenic detoxification by stimulating phosphorylation of the transcription factor Yap8, promoting Yap8 nuclear localization, and stimulating the transcription of the only known Yap8 targets, ARR2 and ARR3, both of which encode proteins that promote arsenic efflux. The related human kinases ERK1 and ERK2 also bound to arsenic in vitro, suggesting that this may be a conserved feature of some members of the mitogen-activated protein kinase (MAPK) family. These data provide a mechanistic basis for understanding how stress-activated kinases can sense distinct threats and perform highly specific adaptive responses.

Dysregulation of very-long-chain fatty acid metabolism causes membrane saturation and induction of the unfolded protein response

The unfolded protein response (UPR) senses defects in the endoplasmic reticulum (ER) and orchestrates a complex program of adaptive cellular remodeling. Increasing evidence suggests an important relationship between lipid homeostasis and the UPR. Defects in the ER membrane induce the UPR, and the UPR in turn controls the expression of some lipid metabolic genes. Among lipid species, the very-long-chain fatty acids (VLCFAs) are relatively rare and poorly understood. Here, we show that loss of the VLCFA-coenzyme A synthetase Fat1, which is essential for VLCFA utilization, results in ER stress with compensatory UPR induction. Comprehensive lipidomic analyses revealed a dramatic increase in membrane saturation in the fat1Δ mutant, likely accounting for UPR induction. In principle, this increased membrane saturation could reflect adaptive membrane remodeling or an adverse effect of VLCFA dysfunction. We provide evidence supporting the latter, as the fat1Δ mutant showed defects in the function of Ole1, the sole fatty acyl desaturase in yeast. These results indicate that VLCFAs play essential roles in protein quality control and membrane homeostasis and suggest an unexpected requirement for VLCFAs in Ole1 function.

Metastatic Basal Cell Carcinoma

OBJECTIVES

Diagnosis of metastatic basal cell carcinoma (BCC) remains challenging, in part due to its rarity. With the advent of molecularly targeted therapies, recognition of this entity is more important than ever.

METHODS

We identified 11 cases of metastatic BCC over a 13-year period. We analyzed these tumors in conjunction with their respective primary tumors by histomorphologic, immunohistochemical, and molecular genetic analyses.

RESULTS

We identified three morphologic patterns of metastasis in BCC. The most common (seven cases) was characterized by completely typical features of BCC. Two cases showed marked squamous differentiation within BCC. The final two cases showed exclusively features of a poorly differentiated carcinoma. One of these was definitively classified by molecular analysis, as both the primary and metastatic tumors harbored the same inactivating PTCH1 mutation.

CONCLUSIONS

This study illustrates multiple distinct morphologic patterns in metastatic BCC and highlights the utility of ancillary molecular testing for accurate diagnosis.

The need for enhanced psychological support in esophageal cancer-an exploratory study of the perception of HCPs, patients, and carers

Esophageal cancer patients and carers report significant levels of psychological distress. Despite this, only a small number of patients and carers engage with existing psychological services. This study aims to explore the perception of esophageal cancer patients, carers, and healthcare professionals (HCPs) of psychological distress and current provision of support, the need for and format of tailored support and barriers to patient/carer engagement. Semistructured interviews were undertaken with n = 14 esophageal cancer patients, carers, and HCPs. Directed content analysis was utilized to code the transcripts according to the preconceived categories as defined by study aim. Participants reported key periods for heightened distress around diagnosis and postsurgery on discharge from hospital. Provision of existing support was not felt to be adequate. A number of patient/carer barriers to engaging with support were identified in addition to HCP barriers. Participants perceived enhanced psychological support as a priority supportive care need with a number of recommendations for tailoring existing support services more adequately to the clinical population. With reports of heightened psychological morbidity yet with few esophageal cancer patients engaging with psychological services, there is an impetus to develop detailed care pathways to facilitate meeting this prioritized support need.

Regulation of the unfolded protein response in yeast by oxidative stress

In the unfolded protein response (UPR), Ire1 activates Hac1 to coordinate the transcription of hundreds of genes to mitigate ER stress. Recent work in Caenorhabditis elegans suggests that oxidative stress inhibits this canonical Ire1 signalling pathway, activating instead an antioxidant stress response. We sought to determine whether this novel mode of UPR function also existed in yeast, where Ire1 has been best characterized. We show that the yeast UPR is also subject to inhibition by oxidative stress. Inhibition is mediated by a single evolutionarily conserved cysteine, and affects both luminal and membrane pathways of Ire1 activation. In yeast, Ire1 appears dispensable for resistance to oxidative stress and, therefore, the physiological significance of this pathway remains to be demonstrated.

352. Towards Earlier Diagnosis of Transmissible Spongiform Encephalopathies (TSEs): A Case Series, Including One Associated With Squirrel Brain Consumption

Background

TSEs present diagnostic and infection control (IC) challenges. Creutzfeldt-Jakob Disease (CJD) is the most common human TSE, occurring in 1–2/million/year in the United States, but other zoonotic factors or transmissions remain incompletely understood. Prompted by the occurrence of four suspected cases from November 2017 to April 2018, we present a case series of suspected CJD to illustrate its variable presentation and the need for more rapid identification for implementation of disease-specific disinfection, sterilization, and quarantine measures.

Methods

We defined a case as any patient with a rapidly progressive dementing or neurologic illness and laboratory tests for CJD. IC and laboratory databases, and electronic medical records were reviewed to identify possible cases from 2013 to 2018.

Results

Five patients met case definition. The average time to suspecting and confirming a diagnosis was 5.2 and 14.2 days, respectively.

Conclusion

Protean in presentation, the diagnosis of CJD can be delayed. Variant CJD and emerging zoonotic TSEs should be considered in differential diagnoses and IC measures. Improved empiric classification algorithms and tests with faster turnaround times are needed.

Disclosures

All authors: No reported disclosures.