Successful Crizotinib-targeted Therapy of Pediatric Unresectable ERC1::ALK Fusion Sarcoma.

Anaplastic lymphoma kinase ( ALK )-fusion sarcomas are rare part of the emerging theoretically targetable tyrosine kinase RAS::MAPK pathway fusion myopericytic-ovoid sarcomas. We report our clinicopathologic and treatment experience with an ALK fusion sarcoma. A novel ELKS/RAB6-interacting/CAST family member 1 - unaligned ALK fusion infiltrative nonmetastatic low-grade sarcoma of the right hand of a 15-month-old male was treated with crizotinib, an ALK tyrosine kinase inhibitor as oral monotherapy, inducing complete radiographic and clinical resolution by 10 months and sustained response now over 12 months after elective discontinuation. Crizotinib can successfully be used to treat unresectable novel ALK fusion sarcomas.

Risk of not being in employment, education or training (NEET) in late adolescence is signalled by school readiness measures at 4-5 years.

BACKGROUND: Not being in employment, education, or training (NEET) is associated with poor health (physical and mental) and social exclusion. We investigated whether England's statutory school readiness measure conducted at 4-5 years provides a risk signal for NEET in late adolescence. METHODS: We identified 8,118 individuals with school readiness measures at 4-5 years and NEET records at 16-17 years using Connected Bradford, a bank of linked routinely collected datasets. Children were categorised as 'school ready' if they reached a 'Good Level of Development' on the Early Years Foundation Stage Profile. We used probit regression and structural equation modelling to investigate the relationship between school readiness and NEET status and whether it primarily relates to academic attainment. RESULTS: School readiness was significantly associated with NEET status. A larger proportion of young people who were not school ready were later NEET (11%) compared to those who were school ready (4%). Most of this effect was attributable to shared relationships with academic attainment, but there was also a direct effect. Measures of deprivation and Special Educational Needs were also strong predictors of NEET status. CONCLUSIONS: NEET risk factors occur early in life. School readiness measures could be used as early indicators of risk, with interventions targeted to prevent the long-term physical and mental health problems associated with NEET, especially in disadvantaged areas. Primary schools are therefore well placed to be public health partners in early intervention strategies.

Click detection rate variability of central North Pacific sperm whales from passive acoustic towed arrays.

Passive acoustic monitoring (PAM) is an optimal method for detecting and monitoring cetaceans as they frequently produce sound while underwater. Cue counting, counting acoustic cues of deep-diving cetaceans instead of animals, is an alternative method for density estimation, but requires an average cue production rate to convert cue density to animal density. Limited information about click rates exists for sperm whales in the central North Pacific Ocean. In the absence of acoustic tag data, we used towed hydrophone array data to calculate the first sperm whale click rates from this region and examined their variability based on click type, location, distance of whales from the array, and group size estimated by visual observers. Our findings show click type to be the most important variable, with groups that include codas yielding the highest click rates. We also found a positive relationship between group size and click detection rates that may be useful for acoustic predictions of group size in future studies. Echolocation clicks detected using PAM methods are often the only indicator of deep-diving cetacean presence. Understanding the factors affecting their click rates provides important information for acoustic density estimation.

Obesity, tidal volume, and pulmonary deposition of fine particulate matter in children with asthma.

BACKGROUND: Obese children with asthma are more vulnerable to air pollution, especially fine particulate matter (PM2.5), but reasons are poorly understood. We hypothesised that differences in breathing patterns (tidal volume, respiratory rate and minute ventilation) due to elevated body mass index (BMI) may contribute to this finding. OBJECTIVE: To investigate the association of BMI with breathing patterns and deposition of inhaled PM2.5. METHODS: Baseline data from a prospective study of children with asthma were analysed (n=174). Tidal breathing was measured by a pitot-tube flowmeter, from which tidal volume, respiratory rate and minute ventilation were obtained. The association of BMI z-score with breathing patterns was estimated in a multivariable model adjusted for age, height, race, sex and asthma severity. A particle dosimetry model simulated PM2.5 lung deposition based on BMI-associated changes in breathing patterns. RESULTS: Higher BMI was associated with higher tidal volume (adjusted mean difference (aMD) between obese and normal-range BMI of 25 mL, 95% CI 5-45 mL) and minute ventilation (aMD 453 mL·min-1, 95% CI 123-784 mL·min-1). Higher tidal volumes caused higher fractional deposition of PM2.5 in the lung, driven by greater alveolar deposition. This translated into obese participants having greater per-breath retention of inhaled PM2.5 (aMD in alveolar deposition fraction of 3.4%, 95% CI 1.3-5.5%), leading to worse PM2.5 deposition rates. CONCLUSIONS: Obese children with asthma breathe at higher tidal volumes that may increase the efficiency of PM2.5 deposition in the lung. This finding may partially explain why obese children with asthma exhibit greater sensitivity to air pollution.

Patterns and predictors of air purifier adherence in children with asthma living in low-income, urban households.

OBJECTIVE: Black children and children from low-income communities are disproportionately affected by asthma, attributed partly to pollution exposure. Air purifiers reduce indoor air pollution and improve asthma symptoms in children. In order to implement air purifier interventions, an understanding of patterns of use and potential barriers is necessary. METHODS: In a home intervention study, 127 children with asthma living in Baltimore were randomized to receive two active or two placebo air purifiers. The 16-week study period included: baseline clinic visit, home visit for air purifier installation (active or placebo) with instruction to use the high or turbo settings, and electronic adherence monitoring of air purifiers. Determinants of adherence were identified using linear regression models. RESULTS: Air purifiers were used 80% of the time, and participants demonstrated adherence to high or turbo settings for 60% of the time. In an adjusted model, season was the major determinant of air purifier adherence, with 21% lower use in the winter (p = 0.025) attributed to the cold draft generated by the machine. CONCLUSION: In a clinical trial with electronic adherence monitoring, air purifier use was high and participants were adherent to use of high or turbo settings the majority of the time. Addressing practical barriers to consistent use, such as draft during the winter, in addition to financial barriers may improve air purifier adherence among children with asthma living in low-income, urban households. CLINICAL TRIALS REGISTRY NUMBER: NCT02763917.

Spatial analysis of tobacco outlet density on secondhand smoke exposure and asthma health among children in Baltimore City.

RATIONALE: Tobacco outlets are concentrated in low-income neighbourhoods; higher tobacco outlet density is associated with increased smoking prevalence. Secondhand smoke (SHS) exposure has significant detrimental effects on childhood asthma. We hypothesised there was an association between higher tobacco outlet density, indoor air pollution and worse childhood asthma. METHODS: Baseline data from a home intervention study of 139 children (8-17 years) with asthma in Baltimore City included residential air nicotine monitoring, paired with serum cotinine and asthma control assessment. Participant addresses and tobacco outlets were geocoded and mapped. Multivariable regression modelling was used to describe the relationships between tobacco outlet density, SHS exposure and asthma control. RESULTS: Within a 500 m radius of each participant home, there were on average six tobacco outlets. Each additional tobacco outlet in a 500 m radius was associated with a 12% increase in air nicotine (p<0.01) and an 8% increase in serum cotinine (p=0.01). For every 10-fold increase in air nicotine levels, there was a 0.25-point increase in Asthma Therapy Assessment Questionnaire (ATAQ) score (p=0.01), and for every 10-fold increase in serum cotinine levels, there was a 0.54-point increase in ATAQ score (p<0.05). CONCLUSIONS: Increased tobacco outlet density is associated with higher levels of bedroom air nicotine and serum cotinine. Increasing levels of SHS exposure (air nicotine and serum cotinine) are associated with less controlled childhood asthma. In Baltimore City, the health of children with asthma is adversely impacted in neighbourhoods where tobacco outlets are concentrated. The implications of our findings can inform community-level interventions to address these health disparities.

Ibuprofen and the Phosphatidylcholine Bilayer: Membrane Water Permeability in the Presence and Absence of Cholesterol.

The interactions between drugs and cell membranes can modulate the structural and physical properties of membranes. The resultant perturbations of the membrane integrity may affect the conformation of the proteins inserted within the membrane, disturbing the membrane-hosted biological functions. In this study, the droplet interface bilayer (DIB), a model cell membrane, is used to examine the effects of ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), on transbilayer water permeability, which is a fundamental membrane biophysical property. Our results indicate that the presence of neutral ibuprofen (pH 3) increases the water permeability of the lipid membranes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). When cholesterol is present with the DOPC, however, the water permeability is not influenced by addition of ibuprofen, regardless of the cholesterol content in DOPC. Given the fact that cholesterol is generally considered to impact packing in the hydrocarbon chain regions, our findings suggest that a potential competition between opposing effects of ibuprofen molecules and cholesterol on the hydrocarbon core environment of the phospholipid assembly may influence the overall water transport phenomena. Results from confocal Raman microspectroscopy and interfacial tensiometry show that ibuprofen molecules induce substantial structural and dynamic changes in the DOPC lipid bilayer. These results, demonstrating that the presence of ibuprofen increases the water permeability of pure DOPC but not that of DOPC-cholesterol mixtures, provide insight into the differential effect of a representative NSAID on heterogeneous biological membranes, depending upon the local composition and structure, results which will signal increased understanding of the gastrointestinal damage and toxicity induced by these molecules.

The association between state-based provisional attendance periods and adolescent middle school-entry vaccination coverage.

The rise of vaccine-preventable disease outbreaks calls for a deeper understanding of the impact of policy on school-entry vaccine compliance. Provisional attendance policies vary by state but permit under-vaccinated students a limited period to attend school while receiving their immunizations. The primary objective of this study was to clarify the relationship between annual immunization coverage and state provisional policies for a single-dose of school-entry-required adolescent vaccinations: tetanus, diphtheria, pertussis (Tdap), meningococcal conjugate (MCV4), and human papillomavirus (HPV). From June 22, 2020 to August 20, 2020, the Immunization Action Coalition and state-level Department of Health (DOH) webpages were reviewed with email confirmation with a DOH representative to determine provisional period policy. Vaccination coverage for Tdap, MCV4, and HPV were obtained from the Center for Disease Control's National Immunization Survey. Overall, 49 states and D.C. legally mandate exclusion of vaccine noncompliant adolescents, and the majority of jurisdictions assign responsibility for exclusion to local school officials (84%). Complete provisional period data was obtained for 46/51 jurisdictions. The effect of provisional period length categorized as 0 days (18 jurisdictions, 35.3%), 1 to 30 days (18 jurisdictions, 35.3%), 31+ days (10 jurisdictions, 19.6%), and "unclear" (5 jurisdictions with incomplete data, 9.8%) had no significant association with annual adolescent vaccination coverage for Tdap (p = 0.82), MCV4 (p = 0.08), and HPV (p = 0.76). Provisional policies may not increase vaccination coverage as anticipated. Unintended consequences, such as increased nonmedical exemptions and increased demands on clinical providers, are additional factors to consider.

Remodeling of the endoplasmic reticulum in Caenorhabditis elegans oocytes is regulated by CGH-1.

A key aspect of development in all metazoans is remodeling at the cellular level. During the development of gametes, remodeling occurs throughout the germ line. When Caenorhabditis elegans hermaphrodites become depleted of sperm after 4 days of adulthood, significant cellular remodeling occurs within the meiotically-arrested oocytes, including the formation of ribonucleoprotein granules. Since major remodeling of the endoplasmic reticulum (ER) occurs in early embryos, we investigated the extent of ER remodeling in meiotically-arrested oocytes. We found, using a combination of fluorescence reporters and transmission electron microscopy, that the ER in arrested oocytes accumulates in patches and sheets that are enriched at the cortex. Our findings suggest this remodeling is not due to simple displacement by large amounts of yolk that accumulate in arrested oocytes, and instead may be genetically regulated. We further identified the Ddx6 RNA helicase, CGH-1, as a key regulator of ER in the germ line. In cgh-1(tn691) oocytes, we detected cortical ER patches as well as aberrant granules of the RNA-binding proteins, PAB-1, MEX-3, and CGH-1. Taken together, our results suggest the possibility that the spatial organization of RNA binding proteins may regulate the translation of mRNAs associated with the ER that in turn, controls the organization of the ER in the adult germ line.

A systematic review of randomized and case-controlled trials investigating the effectiveness of school-based motor skill interventions in 3- to 12-year-old children.

BACKGROUND: Research suggests that children identified with impaired motor skills can respond well to intensive therapeutic interventions delivered via occupational and physical therapy services. There is, however, a need to explore alternative approaches to delivering interventions outside traditional referral-based clinic settings because limited resources mean such health services often struggle to meet demand. This review sets out to systematically assess the evidence for and against school-based interventions targeted at improving the motor skills of children aged between 3 and 12 years old. METHOD: Five electronic databases were searched systematically (AMED, CINAHL, Cochrane, Medline, and PsycINFO) for peer-reviewed articles published between January 2012 and July 2018. Studies were eligible if they implemented a school-based motor skill intervention with a randomized or case-controlled trial design that objectively measured motor skills as an outcome, which were not specific to an athletic or sporting skill. Participants had to be aged between 3 and 12 years old and free from neurological disorders known to affect muscle function. Risk of bias was assessed using the Cochrane risk of bias tool. RESULTS: Twenty-three studies met the inclusion criteria. These studies encompassed interventions targeted at training: fundamental movement skills, handwriting, fine, and global motor skills. The majority of these studies reported beneficial impact on motor function specifically, but some interventions also assessed subsequent impacts on activity and participation (but not well-being). A number of the studies had methodological shortcomings that means these results need to be interpreted with caution. CONCLUSIONS: Schools appear to be an effective setting for motor skill interventions, but the extent of benefit likely depends on the type of intervention. Moreover, confirmation is needed as to whether benefits extend beyond motor function into everyday activities, participation, and well-being. Future research should include follow-up measures to assess the longer term efficacy of school-based interventions.

Healthy volunteers' perceptions of risk in US Phase I clinical trials: A mixed-methods study.

BACKGROUND: There is limited research on healthy volunteers' perceptions of the risks of Phase I clinical trials. In order to contribute empirically to long-standing ethical concerns about healthy volunteers' involvement in drug development, it is crucial to assess how these participants understand trial risks. The objectives of this study were to investigate (1) participants' views of the overall risks of Phase I trials, (2) their views of the risk of personally being harmed in a trial, and (3) how risk perceptions vary across participants' clinical trial history and sociodemographic characteristics. METHODS AND FINDINGS: We qualitatively and quantitatively analyzed semi-structured interviews conducted with 178 healthy volunteers who had participated in a diverse range of Phase I trials in the United States. Participants had collective experience in a reported 1,948 Phase I trials (mean = 10.9; median = 5), and they were interviewed as part of a longitudinal study of healthy volunteers' risk perceptions, their trial enrollment decisions, and their routine health behaviors. Participants' qualitative responses were coded, analyzed, and subsequently quantified in order to assess correlations between their risk perceptions and demographics, such as their race/ethnicity, gender, age, educational attainment, employment status, and household income. We found that healthy volunteers often viewed the overall risks of Phase I trials differently than their own personal risk of harm. The majority of our participants thought that Phase I trials were medium, high, or extremely high risk (118 of 178), but most nonetheless felt that they were personally safe from harm (97 of 178). We also found that healthy volunteers in their first year of clinical trial participation, racial and ethnic minority participants, and Hispanic participants tended to view the overall trial risks as high (respectively, Jonckheere-Terpstra, -2.433, p = 0.015; Fisher exact test, p = 0.016; Fisher exact test, p = 0.008), but these groups did not differ in regard to their perceptions of personal risk of harm (respectively, chi-squared, 3.578, p = 0.059; chi-squared, 0.845, p = 0.358; chi-squared, 1.667, p = 0.197). The main limitation of our study comes from quantitatively aggregating data from in-depth interviews, which required the research team to interpret participants' nonstandardized risk narratives. CONCLUSIONS: Our study demonstrates that healthy volunteers are generally aware of and reflective about Phase I trial risks. The discrepancy in healthy volunteers' views of overall and personal risk sheds light on why healthy volunteers might continue to enroll in clinical trials, even when they view trials on the whole as risky.

The Observational Physician and surGEon Automobile Response (TOP GEAR) survey.

OBJECTIVE: To determine whether surgeons and junior doctors intending to pursue careers in surgery are more likely to purchase more expensive vehicles and to replace them sooner than colleagues of similar seniority pursuing non-surgical careers. DESIGN AND SETTING: Survey of practising medical officers at an Australian tertiary referral hospital. MAIN OUTCOME MEASURES: Car value; proportion of doctors who bought their car new; median time to replacement of vehicle. RESULTS: 154 doctors participated in the survey (17% response rate). 49% were interns, residents or unaccredited registrars, 18% were accredited registrars or fellows, and 31% were consultants; 40% of respondents were surgical trainees or consultants. 59% of surgical trainees and consultants purchased their car new, compared with 38% of non-surgical doctors (P = 0.013); 52% of doctors in the junior surgeon group purchased their car new, compared with 28% of non-surgeon junior doctors (P = 0.019). Median car value was $16 500 (IQR, $9350-37 000) for surgeons and $8500 (IQR, $4400-14 100) for non-surgeons (P < 0.001); 30% of surgeons owned cars valued at more than $50 000, compared with 6% of non-surgeons (P = 0.025). The median time to replacement was 5-7 years for surgeons and 7-10 years for non-surgeons (P < 0.001). CONCLUSIONS: Surgeons more frequently purchase their cars new and replace their cars earlier than non-surgeons, and the median value of their vehicles is higher. These findings were consistent across all levels of seniority.

Biphasic adaptation to osmotic stress in the C. elegans germ line.

Cells respond to environmental stress in multiple ways. In the germ line, heat shock and nutritive stress trigger the assembly of large ribonucleoprotein (RNP) granules via liquid-liquid phase separation (LLPS). The RNP granules are hypothesized to maintain the quality of oocytes during stress. The goal of this study was to investigate the cellular response to glucose in the germ line and determine if it is an osmotic stress response. We found that exposure to 500 mM glucose induces the assembly of RNP granules in the germ line within 1 h. Interestingly, the RNP granules are maintained for up to 3 h; however, they dissociate after longer periods of stress. The RNP granules include processing body and stress granule proteins, suggesting shared functions. Based on several lines of evidence, the germ line response to glucose largely appears to be an osmotic stress response, thus identifying osmotic stress as a trigger of LLPS. Although RNP granules are not maintained beyond 3 h of osmotic stress, the quality of oocytes does not appear to decrease after longer periods of stress, suggesting a secondary adaptation in the germ line. We used an indirect marker of glycerol and observed high levels after 5 and 20 h of glucose exposure. Moreover, in gpdh-1;gpdh-2 germ lines, glycerol levels are reduced concomitant with RNP granules being maintained for an extended period. We speculate that increased glycerol levels may function as a secondary osmoregulatory adaptive response in the germ line, following a primary response of RNP granule assembly.

Friendship Security, But Not Friendship Intimacy, Moderates the Stability of Anxiety During Preadolescence.

A two-wave longitudinal study of 380 preadolescents (M age = 10.87) from largely middle-class schools in Montréal, Québec, Canada, assessed the hypothesis that friendship security, but not friendship intimacy, moderates the stability of anxiety during adolescence. This central but largely overlooked question about peer relations concerns which aspects of friendship account for the effects of friendship on emotional adjustment. Anxiety and friendship quality were measured via self-report questionnaires, employing the Network of Relationships Inventory for security and intimacy items. An index of friendship durability, which combined reciprocity and stability within first- and second-best friendship choices, was derived from sociometric measures. A latent variable path analysis examined with structural equation modeling showed that anxiety was less stable for children who perceived their friendships as secure. The moderating effect of intimacy was statistically nonsignificant. A follow-up analysis showed that the effects of security did not result from friendship durability. These findings provide support for the long-standing but previously unaddressed hypothesis that security, rather than intimacy, accounts for friendship's effect on anxiety reduction during early adolescence.

TNF-α augments RANKL-dependent intestinal M cell differentiation in enteroid cultures.

Microfold (M) cells are phagocytic intestinal epithelial cells in the follicle-associated epithelium of Peyer's patches that transport particulate antigens from the gut lumen into the subepithelial dome. Differentiation of M cells from epithelial stem cells in intestinal crypts requires the cytokine receptor activator of NF-κB ligand (RANKL) and the transcription factor Spi-B. We used three-dimensional enteroid cultures established with small intestinal crypts from mice as a model system to investigate signaling pathways involved in M cell differentiation and the influence of other cytokines on RANKL-induced M cell differentiation. Addition of RANKL to enteroids induced expression of multiple M cell-associated genes, including Spib, Ccl9 [chemokine (C-C motif) ligand 9], Tnfaip2 (TNF-α-induced protein 2), Anxa5 (annexin A5), and Marcksl1 (myristoylated alanine-rich protein kinase C substrate) in 1 day. The mature M cell marker glycoprotein 2 (Gp2) was strongly induced by 3 days and expressed by 11% of cells in enteroids. The noncanonical NF-κB pathway was required for RANKL-induced M cell differentiation in enteroids, as addition of RANKL to enteroids from mice with a null mutation in the mitogen-activated protein kinase kinase kinase 14 (Map3k14) gene encoding NF-κB-inducing kinase failed to induce M cell-associated genes. While the cytokine TNF-α alone had little, if any, effect on expression of M cell-associated genes, addition of TNF-α to RANKL consistently resulted in three- to sixfold higher levels of multiple M cell-associated genes than RANKL alone. One contributing mechanism is the rapid induction by TNF-α of Relb and Nfkb2 (NF-κB subunit 2), genes encoding the two subunits of the noncanonical NF-κB heterodimer. We conclude that endogenous activators of canonical NF-κB signaling present in the gut-associated lymphoid tissue microenvironment, including TNF-α, can play a supportive role in the RANKL-dependent differentiation of M cells in the follicle-associated epithelium.

Psychiatrists' Perceptions of World of Warcraft and Other MMORPGs.

Video game use, particularly massively-multiplayer online games (MMOs) and massively-multiplayer online role-playing games (MMORPGs), has been a focus of considerable research in recent years. However, little is known regarding how mental health workers perceive patients and clients who report playing them. The present study examines whether psychiatrists play MMOs/MMORPGs and how they perceive those who play them. Psychiatrists (N = 48) at a tertiary care centre in Canada completed a questionnaire assessing history of playing video games as well as whether they associate such use with psychopathology. Only 36.7 % believed there was an association between psychopathology and MMO/MMORPG use. Implications for clinical practice and future research are discussed.

Psychiatrists' Perceptions of Facebook and Other Social Media.

The literature has seen a surge in research on the mental health impacts of technologies such as Facebook, Twitter and other social media, but little is known regarding how mental health workers perceive patients and clients who report use of such technologies. The present study examines how psychiatrists perceive social media and whether they make use of it. Psychiatrists (N = 48) at a tertiary care centre in Canada completed a questionnaire assessing history of using social networking sites (SNSs) such as Facebook and Google Plus and status update sites (SUSs) such as Twitter and Livejournal and whether they associate them with psychopathology. 38.5 % have used SNSs and 9.8 % have used SUSs. Only 37 % believed there was an association between psychopathology and SNSs while 33 % believed there was an association between psychopathology and SUSs. Implications for clinical practice and future research are discussed.

Damage-evoked signals in cochlear neurons and supporting cells.

In addition to hearing loss, damage to the cochlea can lead to gain of function pathologies such as hyperacusis. It has been proposed that painful hyperacusis, noxacusis, may be carried to the central nervous system by type II cochlear afferents, sparse, unmyelinated neurons that share morphological and neurochemical traits with nociceptive C-fibers of the somatic nervous system. Also like in skin, damage elicits spreading calcium waves within cochlear epithelia. These are mediated by extracellular ATP combined with IP3-driven release from intracellular calcium stores. Type II afferents are excited by ATP released from damaged epithelia. Thus, the genesis and propagation of epithelial calcium waves is central to cochlear pathology, and presumably hyperacusis. Damage-evoked signals in type II afferents and epithelial cells have been recorded in cochlear explants or semi-intact otic capsules. These efforts have included intracellular electrical recording, use of fluorescent calcium indicators, and visualization of an activity-dependent, intrinsic fluorescent signal. Of relevance to hyperacusis, prior noise-induced hearing loss leads to the generation of prolonged and repetitive activity in type II neurons and surrounding epithelia.

Programmed Death Ligand 1-Expressing Macrophages and Their Protective Role in the Joint During Arthritis.

OBJECTIVE: Arthritis associated with immune checkpoint inhibitor therapies highlights the importance of immune checkpoint expression for joint homeostasis. We investigated the role of programmed death ligand (PD-L) 1 in the synovium using a collagen-induced arthritis (CIA) mouse model. METHODS: We blocked PD-L1 using blocking antibodies during CIA and assessed the arthritis severity by clinical and histologic scoring. PD-L1 expression and the origin of synovial macrophages were investigated using flow cytometry and parabiosis. We used Cre-Lox mice to ascertain the protective role of PD-L1-expressing macrophages in arthritis. The immune profile of human and murine synovial PD-L1+ macrophages was determined by reverse transcriptase-polymerase chain reaction, flow cytometry, and single-cell RNA sequencing. RESULTS: Anti-PD-L1 antibody treatment during CIA worsened arthritis with increased immune cell infiltration compared with isotype control, supporting the regulatory role of PD-L1 in the joint. The main cells expressing PD-L1 in the synovium were macrophages. Using parabiosis, we showed that synovial PD-L1+ macrophages were both locally proliferating and partially replaced by the circulation. PD-L1+ macrophages had increased levels of MER proto-oncogene tyrosine kinase (MerTK) and interleukin (IL)-10 expression during acute CIA. Genetic depletion of PD-L1 on macrophages in LyzcrePD-L1fl/fl mice resulted in worsened CIA compared with controls. We found that human PD-L1+ macrophages in the synovium of healthy individuals and patients with rheumatoid arthritis express MerTK and IL-10. CONCLUSION: PD-L1+ macrophages with efferocytotic and anti-inflammatory characteristics protect the synovium from severe arthritis in the CIA mouse model. Tissue-protective, PD-L1-expressing macrophages are also present in the human synovium at homeostasis and during rheumatoid arthritis.

α-catenin middle- and actin-binding domain unfolding mutants differentially impact epithelial strength and sheet migration.

α-catenin (α-cat) displays force-dependent unfolding and binding to actin filaments through direct and indirect means, but features of adherens junction structure and function most vulnerable to loss of these allosteric mechanisms have not been directly compared. By reconstituting an α-cat F-actin-binding domain unfolding mutant known to exhibit enhanced binding to actin (α-cat-H0-FABD+) into α-cat knockout Madin Darby Canine Kidney (MDCK) cells, we show that partial loss of the α-cat catch bond mechanism (via an altered H0 α-helix) leads to stronger epithelial sheet integrity with greater colocalization between the α-cat-H0-FABD+ mutant and actin. α-cat-H0-FABD+ -expressing cells are less efficient at closing scratch-wounds, suggesting reduced capacity for more dynamic cell-cell coordination. Evidence that α-cat-H0-FABD+ is equally accessible to the conformationally sensitive α18 antibody epitope as WT α-cat and shows similar vinculin recruitment suggests this mutant engages lower tension cortical actin networks, as its M-domain is not persistently open. Conversely, α-cat-M-domain salt-bridge mutants with persistent recruitment of vinculin and phosphorylated myosin light chain show only intermediate monolayer adhesive strengths, but display less directionally coordinated and thereby slower migration speeds during wound-repair. These data show α-cat M- and FABD-unfolding mutants differentially impact cell-cell cohesion and migration properties, and suggest signals favoring α-cat-cortical actin interaction without persistent M-domain opening may improve epithelial monolayer strength through enhanced coupling to lower tension actin networks.