SUMO protease FUG1, histone reader AL3 and chromodomain protein LHP1 are integral to repeat expansion-induced gene silencing in Arabidopsis thaliana.

Epigenetic gene silencing induced by expanded repeats can cause diverse phenotypes ranging from severe growth defects in plants to genetic diseases such as Friedreich's ataxia in humans. The molecular mechanisms underlying repeat expansion-induced epigenetic silencing remain largely unknown. Using a plant model with a temperature-sensitive phenotype, we have previously shown that expanded repeats can induce small RNAs, which in turn can lead to epigenetic silencing through the RNA-dependent DNA methylation pathway. Here, using a genetic suppressor screen and yeast two-hybrid assays, we identified novel components required for epigenetic silencing caused by expanded repeats. We show that FOURTH ULP GENE CLASS 1 (FUG1)-an uncharacterized SUMO protease with no known role in gene silencing-is required for epigenetic silencing caused by expanded repeats. In addition, we demonstrate that FUG1 physically interacts with ALFIN-LIKE 3 (AL3)-a histone reader that is known to bind to active histone mark H3K4me2/3. Loss of function of AL3 abolishes epigenetic silencing caused by expanded repeats. AL3 physically interacts with the chromodomain protein LIKE HETEROCHROMATIN 1 (LHP1)-known to be associated with the spread of the repressive histone mark H3K27me3 to cause repeat expansion-induced epigenetic silencing. Loss of any of these components suppresses repeat expansion-associated phenotypes coupled with an increase in IIL1 expression with the reversal of gene silencing and associated change in epigenetic marks. Our findings suggest that the FUG1-AL3-LHP1 module is essential to confer repeat expansion-associated epigenetic silencing and highlight the importance of post-translational modifiers and histone readers in epigenetic silencing.

Experimentally manipulated anger activates implicit cognitions about social hierarchy.

A correlational pilot study (N = 143) and an integrative data analysis of two experiments (total N = 377) provide evidence linking anger to the psychology of social hierarchy. The experiments demonstrate that the experience of anger increases the psychological accessibility of implicit cognitions related to social hierarchy: compared to participants in a control condition, participants in an anger-priming condition completed word stems with significantly more hierarchy-related words. We found little support for sex differences in the effect of anger on implicit hierarchy-related cognition; effects were equivalent across male and female participants. Findings fit with functionalist evolutionary views of anger suggesting that anger may motivate the use of dominance to strive for high social rank in group hierarchies. Implications for downstream behaviour, including aggression and negotiation, are discussed.

Emergent Spatiotemporal Organization in Stochastic Intracellular Transport Dynamics.

The interior of a living cell is an active, fluctuating, and crowded environment, yet it maintains a high level of coherent organization. This dichotomy is readily apparent in the intracellular transport system of the cell. Membrane-bound compartments called endosomes play a key role in carrying cargo, in conjunction with myriad components including cargo adaptor proteins, membrane sculptors, motor proteins, and the cytoskeleton. These components coordinate to effectively navigate the crowded cell interior and transport cargo to specific intracellular locations, even though the underlying protein interactions and enzymatic reactions exhibit stochastic behavior. A major challenge is to measure, analyze, and understand how, despite the inherent stochasticity of the constituent processes, the collective outcomes show an emergent spatiotemporal order that is precise and robust. This review focuses on this intriguing dichotomy, providing insights into the known mechanisms of noise suppression and noise utilization in intracellular transport processes, and also identifies opportunities for future inquiry. Expected final online publication date for the Annual Review of Biophysics, Volume 53 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Clinical Utility of Melanoma Sentinel Lymph Node Biopsy Nomograms.

BACKGROUND: For patients with melanoma, the decision to perform sentinel lymph node biopsy (SLNB) is based on the estimated risk of lymph node metastasis. We assessed 3 melanoma SLNB risk-prediction models' statistical performance and their ability to improve clinical decision making (clinical utility) on a cohort of melanoma SLNB cases. STUDY DESIGN: Melanoma patients undergoing SLNB at a single center from 2003 to 2021 were identified. The predicted probabilities of sentinel lymph node positivity using the Melanoma Institute of Australia, Memorial Sloan Kettering Cancer Center (MSK), and Friedman nomograms were calculated. Receiver operating characteristic and calibration curves were generated. Clinical utility was assessed via decision curve analysis, calculating the net SLNBs that could have been avoided had a given model guided selection at different risk thresholds. RESULTS: Of 2,464 melanoma cases that underwent SLNB, 567 (23.0%) had a positive sentinel lymph node. The areas under the receiver operating characteristic curves for the Melanoma Institute of Australia, MSK, and Friedman models were 0.726 (95% CI, 0.702 to 0.750), 0.720 (95% CI, 0.697 to 0.744), and 0.721 (95% CI, 0.699 to 0.744), respectively. For all models, calibration was best at predicted positivity rates below 30%. The MSK model underpredicted risk. At a 10% risk threshold, only the Friedman model would correctly avoid a net of 6.2 SLNBs per 100 patients. The other models did not reduce net avoidable SLNBs at risk thresholds of ≤10%. CONCLUSIONS: The tested nomograms had comparable performance in our cohort. The only model that achieved clinical utility at risk thresholds of ≤10% was the Friedman model.

EZH2 is a key component of hepatoblastoma tumor cell growth.

BACKGROUND: Enhancer of zeste homolog 2 (EZH2) catalyzes the trimethylation of histone H3 at lysine 27 via the polycomb recessive complex 2 (PRC2) and plays a time-specific role in normal fetal liver development. EZH2 is overexpressed in hepatoblastoma (HB), an embryonal tumor. EZH2 can also promote tumorigenesis via a noncanonical, PRC2-independent mechanism via proto-oncogenic, direct protein interaction, including ß-catenin. We hypothesize that the pathological activation of EZH2 contributes to HB propagation in a PRC2-independent manner. METHODS AND RESULTS: We demonstrate that EZH2 promotes proliferation in HB tumor-derived cell lines through interaction with ß-catenin. Although aberrant EZH2 expression occurs, we determine that both canonical and noncanonical EZH2 signaling occurs based on specific gene-expression patterns and interaction with SUZ12, a PRC2 component, and ß-catenin. Silencing and inhibition of EZH2 reduce primary HB cell proliferation. CONCLUSIONS: EZH2 overexpression promotes HB cell proliferation, with both canonical and noncanonical function detected. However, because EZH2 directly interacts with ß-catenin in human tumors and EZH2 overexpression is not equal to SUZ12, it seems that a noncanonical mechanism is contributing to HB pathogenesis. Further mechanistic studies are necessary to elucidate potential pathogenic downstream mechanisms and translational potential of EZH2 inhibitors for the treatment of HB.

Mu-opioid receptor knockout on Foxp2-expressing neurons leads to reduced aversion-resistant reward seeking.

Mu-opioid receptors (MORs) in the amygdala and striatum are important in addictive and rewarding behaviors. Foxp2 is a marker of intercalated (ITC) cells in the amygdala and a subset of striatal medium spiny neurons (MSNs), both of which express MORs in wild-type mice. For the current series of studies, we characterized the behavior of mice with genetic deletion of the MOR gene Oprm1 in Foxp2-expressing neurons (Foxp2-Cre/Oprm1 fl/fl ). Male and female Foxp2-Cre/Oprm1 fl/fl mice were generated and heterozygous Cre+ (knockout) and homozygous Cre-(control) animals were tested for aversion-resistant alcohol consumption using an intermittent access (IA) task, operant responding for a sucrose reward, conditioned place aversion (CPA) to morphine withdrawal, and locomotor sensitization to morphine. In IA, mice with the MOR-knockout were more sensitive to quinine-adulterated ethanol (EtOH) and less aversion-resistant, as they decreased EtOH consumption from baseline at all quinine concentrations, while control animals did not. In operant conditioning, Cre+ mice similarly exhibited less aversion-resistant reward seeking than Cre-mice when sucrose was adulterated with quinine. For CPA, both control and MOR-knockout mice demonstrated withdrawal-induced aversion. For locomotor sensitization, Cre+ mice demonstrated decreased locomotion following morphine injection compared to Cre-mice. The results of these studies suggest that MOR expression on Foxp2-expressing neurons is not necessary for rewarded behaviors or expression of opioid withdrawal but may be involved in aversion-resistance.

Urinary bladder matrix devices support closure in complex sacral wounds.

The management of sacral wounds is often complicated by patient comorbidities and anatomical factors. This retrospective case series describes the management of 5 complex sacral wounds in which UBM devices were applied to facilitate wound closure. The wounds in this series were exacerbated by comorbidities and challenging wound presentations including tunneling and exposed bone. In this series, application of UBM particulate and sheets supported progressive wound closure, marked by neo-tissue formation and depth reduction with closure of tunneling in all cases. Results from this series underscore the utility of UBM devices in the management of sacral wounds and especially those further hindered by extensive tunneling.

Deterministic early endosomal maturations emerge from a stochastic trigger-and-convert mechanism.

Endosomal maturation is critical for robust and timely cargo transport to specific cellular compartments. The most prominent model of early endosomal maturation involves a phosphoinositide-driven gain or loss of specific proteins on individual endosomes, emphasising an autonomous and stochastic description. However, limitations in fast, volumetric imaging long hindered direct whole cell-level measurements of absolute numbers of maturation events. Here, we use lattice light-sheet imaging and bespoke automated analysis to track individual very early (APPL1-positive) and early (EEA1-positive) endosomes over the entire population, demonstrating that direct inter-endosomal contact drives maturation between these populations. Using fluorescence lifetime, we show that this endosomal interaction is underpinned by asymmetric binding of EEA1 to very early and early endosomes through its N- and C-termini, respectively. In combination with agent-based simulation which supports a 'trigger-and-convert' model, our findings indicate that APPL1- to EEA1-positive maturation is driven not by autonomous events but by heterotypic EEA1-mediated interactions, providing a mechanism for temporal and population-level control of maturation.

Non-Native Site-Selective Enzyme Catalysis.

The ability to site-selectively modify equivalent functional groups in a molecule has the potential to streamline syntheses and increase product yields by lowering step counts. Enzymes catalyze site-selective transformations throughout primary and secondary metabolism, but leveraging this capability for non-native substrates and reactions requires a detailed understanding of the potential and limitations of enzyme catalysis and how these bounds can be extended by protein engineering. In this review, we discuss representative examples of site-selective enzyme catalysis involving functional group manipulation and C-H bond functionalization. We include illustrative examples of native catalysis, but our focus is on cases involving non-native substrates and reactions often using engineered enzymes. We then discuss the use of these enzymes for chemoenzymatic transformations and target-oriented synthesis and conclude with a survey of tools and techniques that could expand the scope of non-native site-selective enzyme catalysis.

FOXO3 Deficiency in Neutrophils Drives Colonic Inflammation and Tumorigenesis.

Inflammatory bowel disease (IBD), characterized by infiltration of polymorphonuclear neutrophils (PMNs), increases the risk of colon cancer. PMN activation corresponds to the accumulation of intracellular Lipid Droplets (LDs). As increased LDs are negatively regulated by transcription factor Forkhead Box O3 (FOXO3), we aim to determine the significance of this regulatory network in PMN-mediated IBD and tumorigenesis. Affected tissue of IBD and colon cancer patients, colonic and infiltrated immune cells, have increased LDs' coat protein, PLIN2. Mouse peritoneal PMNs with stimulated LDs and FOXO3 deficiency have elevated transmigratory activity. Transcriptomic analysis of these FOXO3-deficient PMNs showed differentially expressed genes (DEGs; FDR < 0.05) involved in metabolism, inflammation, and tumorigenesis. Upstream regulators of these DEGs, similar to colonic inflammation and dysplasia in mice, were linked to IBD and human colon cancer. Additionally, a transcriptional signature representing FOXO3-deficient PMNs (PMN-FOXO3389) separated transcriptomes of affected tissue in IBD (p = 0.00018) and colon cancer (p = 0.0037) from control. Increased PMN-FOXO3389 presence predicted colon cancer invasion (lymphovascular p = 0.015; vascular p = 0.046; perineural p = 0.03) and poor survival. Validated DEGs from PMN-FOXO3389 (P2RX1, MGLL, MCAM, CDKN1A, RALBP1, CCPG1, PLA2G7) are involved in metabolism, inflammation, and tumorigenesis (p < 0.05). These findings highlight the significance of LDs and FOXO3-mediated PMN functions that promote colonic pathobiology.

Termination of STING responses is mediated via ESCRT-dependent degradation.

cGAS-STING signalling is induced by detection of foreign or mislocalised host double-stranded (ds)DNA within the cytosol. STING acts as the major signalling hub, where it controls production of type I interferons and inflammatory cytokines. Basally, STING resides on the ER membrane. Following activation STING traffics to the Golgi to initiate downstream signalling and subsequently to endolysosomal compartments for degradation and termination of signalling. While STING is known to be degraded within lysosomes, the mechanisms controlling its delivery remain poorly defined. Here we utilised a proteomics-based approach to assess phosphorylation changes in primary murine macrophages following STING activation. This identified numerous phosphorylation events in proteins involved in intracellular and vesicular transport. We utilised high-temporal microscopy to track STING vesicular transport in live macrophages. We subsequently identified that the endosomal complexes required for transport (ESCRT) pathway detects ubiquitinated STING on vesicles, which facilitates the degradation of STING in murine macrophages. Disruption of ESCRT functionality greatly enhanced STING signalling and cytokine production, thus characterising a mechanism controlling effective termination of STING signalling.

Utilizing computed tomography volumetry for size matching prior to lung transplantation: a case series.

Background: Appropriate size matching between donor and recipient is critical for successful pulmonary transplantation. Although surrogate measurements such as height and gender are often utilized to approximate predicted lung volume, these methods provide only a gross estimation with wide variability and poor predictive value. Case Description: A single center exploratory study was conducted in which four patients underwent lung transplantation (LT) with pre-operative computed tomography (CT) volumetry obtained in both the donor and recipient to facilitate decision making regarding organ size and suitability. In four cases in which CT volumetry was used, the lung volumes calculated using surrogate measurements significantly overestimated both donor and recipient lung volumes quantified by CT volumetric analysis. All recipients underwent successful LT without necessary graft downsizing. Conclusions: This is an initial report of prospectively utilizing CT volumetry as an adjunct to decision-making regarding suitability of donor lungs. In these cases, CT volumetry facilitated the confident acceptance of donor lungs that were initially predicted to be oversized based on other clinical measures.

Structural and Functional Impact of Posttranslational Modification of Glypican-3 on Liver Carcinogenesis.

Glypican-3 (GPC3) is a cell-surface glycoprotein that is frequently overexpressed in hepatocellular carcinoma (HCC). GPC3 undergoes extensive posttranslational modification (PTM) including cleavage and glycosylation. This review focuses on the structure and function of GPC3 in liver cancer, highlighting the PTM of the tertiary and quaternary structures of GPC3 as a potential oncogenic regulatory mechanism. We propose that the function of GPC3 in normal development can vary with extensive PTM and that dysregulation of these processes leads to disease. Defining the regulatory impact of these modifications can provide a deeper understanding of the role of GPC3 in oncogenesis, epithelial-mesenchymal transition, and drug development. Through review of current literature, this article provides a unique perspective on the role of GPC3 in liver cancer, focusing on potential regulatory mechanisms of PTM on GPC3 function at the molecular, cellular, and disease level.

The ClC-2 Chloride Channel Activator, Lubiprostone, Improves Intestinal Barrier Function in Biopsies from Crohn's Disease but Not Ulcerative Colitis Patients.

The prostone analog, lubiprostone, is approved to manage constipation-predominant irritable bowel syndrome. Lubiprostone also protects intestinal mucosal barrier function in animal models of colitis. The aim of this study was to determine if lubiprostone improves barrier properties in isolated colonic biopsies from Crohn's disease (CD) and ulcerative colitis (UC) patients. Sigmoid colon biopsies from healthy subjects, CD and UC patients in remission, and CD patients with active disease were mounted in Ussing chambers. Tissues were treated with lubiprostone or vehicle to determine the effects on transepithelial electrical resistance (TER), FITC-dextran 4kD (FD4) permeability, and electrogenic ion transport responses to forskolin and carbachol. Localization of the tight junction protein, occludin, was determined by immunofluorescence. Lubiprostone significantly increased ion transport across control, CD and UC remission biopsies but not active CD. Lubiprostone selectively improved TER in both CD remission and active disease biopsies but not in control or UC biopsies. The improved TER was associated with increased membrane localization of occludin. Lubiprostone selectively improved barrier properties of biopsies from CD patients vs. UC and independent of an ion transport response. These data indicate that lubiprostone has potential efficacy in improving mucosal integrity in Crohn's disease.

Are the MIA and MSKCC nomograms useful in selecting patients with melanoma for sentinel lymph node biopsy?

BACKGROUND AND METHODS: The Melanoma Institute of Australia (MIA) and Memorial Sloan Kettering Cancer Center (MSKCC) nomograms were developed to help guide sentinel lymph node biopsy (SLNB) decisions. Although statistically validated, whether these prediction models provide clinical benefit at National Comprehensive Cancer Network guideline-endorsed thresholds is unknown. We conducted a net benefit analysis to quantify the clinical utility of these nomograms at risk thresholds of 5%-10% compared to the alternative strategy of biopsying all patients. External validation data for MIA and MSKCC nomograms were extracted from respective published studies. RESULTS: The MIA nomogram provided added net benefit at a risk threshold of 9% but net harm at 5%-8% and 10%. The MSKCC nomogram provided added net benefit at risk thresholds of 5% and 9%-10% but net harm at 6%-8%. When present, the magnitude of net benefit was small (1-3 net avoidable biopsies per 100 patients). CONCLUSION: Neither model consistently provided added net benefit compared to performing SLNB for all patients. DISCUSSION: Based on published data, use of the MIA or MSKCC nomograms as decision-making tools for SLNB at risk thresholds of 5%-10% does not clearly provide clinical benefit to patients.

American Society for Gastrointestinal Endoscopy guideline on management of post-liver transplant biliary strictures: summary and recommendations.

This clinical practice guideline from the American Society for Gastrointestinal Endoscopy provides an evidence-based approach for strategies to manage biliary strictures in liver transplant recipients. This document was developed using the Grading of Recommendations Assessment, Development and Evaluation framework. The guideline addresses the role of ERCP versus percutaneous transhepatic biliary drainage and covered self-expandable metal stents (cSEMSs) versus multiple plastic stents for therapy of post-transplant strictures, use of MRCP for diagnosing post-transplant biliary strictures, and administration of antibiotics versus no antibiotics during ERCP. In patients with post-transplant biliary strictures, we suggest ERCP as the initial intervention and cSEMSs as the preferred stent for extrahepatic strictures. In patients with unclear diagnoses or intermediate probability of a stricture, we suggest MRCP as the diagnostic modality. We suggest that antibiotics should be administered during ERCP when biliary drainage cannot be ensured.

American Society for Gastrointestinal Endoscopy guideline on management of post-liver transplant biliary strictures: methodology and review of evidence.

This clinical practice guideline from the American Society for Gastrointestinal Endoscopy provides an evidence-based approach for strategies to manage biliary strictures in liver transplant recipients. This document was developed using the Grading of Recommendations Assessment, Development and Evaluation framework. The guideline addresses the role of ERCP versus percutaneous transhepatic biliary drainage and covered self-expandable metal stents (cSEMSs) versus multiple plastic stents for therapy of strictures, use of MRCP for diagnosing post-transplant biliary strictures, and administration of antibiotics versus no antibiotics during ERCP. In patients with post-transplant biliary strictures, we suggest ERCP as the initial intervention and cSEMSs as the preferred stent. In patients with unclear diagnosis or intermediate probability of a stricture, we suggest MRCP as the diagnostic modality. We suggest that antibiotics should be administered during ERCP when biliary drainage cannot be assured.

A Structured Discharge Education Intervention for Parents of Newly Diagnosed Pediatric Oncology Patients.

Background: Parents of children newly diagnosed with cancer require specialized knowledge and skills in order to safely care for their children at home. The Children's Oncology Group (COG) developed expert consensus recommendations to guide new diagnosis education; however, these recommendations have not been empirically tested. Methods: We used a sequential two-cohort study design to test a nurse-led Structured Discharge Teaching Intervention (SDTI) that operationalizes the COG expert recommendations in the setting of a tertiary children's hospital. Outcomes included parent Readiness for Hospital Discharge Scale (RHDS); Quality of Discharge Teaching Scale (QDTS); Post-Discharge Coping Difficulty (PDCD); Nurse Satisfaction; and post-discharge unplanned healthcare utilization. Results: The process for discharge education changed significantly before and after implementation of the SDTI, with significantly fewer instances of one-day discharge teaching, and higher involvement of staff nurses in teaching. Overall, parental RHDS, QDTS, and PDCD scores were similar in the unintervened and intervened cohorts. Almost 60% of patients had unplanned healthcare encounters during the first 30 days following their initial hospital discharge. Overall nurse satisfaction with the quality and process of discharge education significantly increased post-intervention. Discussion: Although the structure for and process of delivering discharge education changed significantly with implementation of the SDTI, parent RHDS and QDTS scores remained uniformly high and PDCD scores and non-preventable unplanned healthcare utilization remained similar, while nurse satisfaction with the quality and process of discharge education significantly improved, suggesting that further testing of the SDTI across diverse pediatric oncology settings is warranted.