Sequence reliance of the Drosophila context-dependent transcription factor CLAMP.

Despite binding similar cis elements in multiple locations, a single transcription factor (TF) often performs context-dependent functions at different loci. How factors integrate cis sequence and genomic context is still poorly understood and has implications for off-target effects in genetic engineering. The Drosophila context-dependent TF chromatin-linked adaptor for male-specific lethal proteins (CLAMP) targets similar GA-rich cis elements on the X-chromosome and at the histone gene locus but recruits very different, locus-specific factors. We discover that CLAMP leverages information from both cis element and local sequence to perform context-specific functions. Our observations imply the importance of other cues, including protein-protein interactions and the presence of additional cofactors.

Differential cognitive and behavioral development from 6 to 24 months in autism and fragile X syndrome.

BACKGROUND: Specifying early developmental differences among neurodevelopmental disorders with distinct etiologies is critical to improving early identification and tailored intervention during the first years of life. Recent studies have uncovered important differences between infants with fragile X syndrome (FXS) and infants with familial history of autism spectrum disorder who go on to develop autism themselves (FH-ASD), including differences in brain development and behavior. Thus far, there have been no studies longitudinally investigating differential developmental skill profiles in FXS and FH-ASD infants. METHODS: The current study contrasted longitudinal trajectories of verbal (expressive and receptive language) and nonverbal (gross and fine motor, visual reception) skills in FXS and FH-ASD infants, compared to FH infants who did not develop ASD (FH-nonASD) and typically developing controls. RESULTS: Infants with FXS showed delays on a nonverbal composite compared to FH-ASD (as well as FH-nonASD and control) infants as early as 6 months of age. By 12 months an ordinal pattern of scores was established between groups on all domains tested, such that controls > FH-nonASD > FH-ASD > FXS. This pattern persisted through 24 months. Cognitive level differentially influenced developmental trajectories for FXS and FH-ASD. CONCLUSIONS: Our results demonstrate detectable group differences by 6 months between FXS and FH-ASD as well as differential trajectories on each domain throughout infancy. This work further highlights an earlier onset of global cognitive delays in FXS and, conversely, a protracted period of more slowly emerging delays in FH-ASD. Divergent neural and cognitive development in infancy between FXS and FH-ASD contributes to our understanding of important distinctions in the development and behavioral phenotype of these two groups.

ATF6 protects against protein misfolding during cardiac hypertrophy.

Cardiomyocytes activate the unfolded protein response (UPR) transcription factor ATF6 during pressure overload-induced hypertrophic growth. The UPR is thought to increase ER protein folding capacity and maintain proteostasis. ATF6 deficiency during pressure overload leads to heart failure, suggesting that ATF6 protects against myocardial dysfunction by preventing protein misfolding. However, conclusive evidence that ATF6 prevents toxic protein misfolding during cardiac hypertrophy is still pending. Here, we found that activation of the UPR, including ATF6, is a common response to pathological cardiac hypertrophy in mice. ATF6 KO mice failed to induce sufficient levels of UPR target genes in response to chronic isoproterenol infusion or transverse aortic constriction (TAC), resulting in impaired cardiac growth. To investigate the effects of ATF6 on protein folding, the accumulation of poly-ubiquitinated proteins as well as soluble amyloid oligomers were directly quantified in hypertrophied hearts of WT and ATF6 KO mice. Whereas only low levels of protein misfolding was observed in WT hearts after TAC, ATF6 KO mice accumulated increased quantities of misfolded protein, which was associated with impaired myocardial function. Collectively, the data suggest that ATF6 plays a critical adaptive role during cardiac hypertrophy by protecting against protein misfolding.

Associations between early trajectories of amygdala development and later school-age anxiety in two longitudinal samples.

Amygdala function is implicated in the pathogenesis of autism spectrum disorder (ASD) and anxiety. We investigated associations between early trajectories of amygdala growth and anxiety and ASD outcomes at school age in two longitudinal studies: high- and low-familial likelihood for ASD, Infant Brain Imaging Study (IBIS, n = 257) and typically developing (TD) community sample, Early Brain Development Study (EBDS, n = 158). Infants underwent MRI scanning at up to 3 timepoints from neonate to 24 months. Anxiety was assessed at 6-12 years. Linear multilevel modeling tested whether amygdala volume growth was associated with anxiety symptoms at school age. In the IBIS sample, children with higher anxiety showed accelerated amygdala growth from 6 to 24 months. ASD diagnosis and ASD familial likelihood were not significant predictors. In the EBDS sample, amygdala growth from birth to 24 months was associated with anxiety. More anxious children had smaller amygdala volume and slower rates of amygdala growth. We explore reasons for the contrasting results between high-familial likelihood for ASD and TD samples, grounding results in the broader literature of variable associations between early amygdala volume and later anxiety. Results have the potential to identify mechanisms linking early amygdala growth to later anxiety in certain groups.

Sequence reliance of a Drosophila context-dependent transcription factor.

Despite binding similar cis elements in multiple locations, a single transcription factor often performs context-dependent functions at different loci. How factors integrate cis sequence and genomic context is still poorly understood and has implications for off-target effects in genetic engineering. The Drosophila context-dependent transcription factor CLAMP targets similar GA-rich cis elements on the X-chromosome and at the histone gene locus but recruits very different, loci-specific factors. We discover that CLAMP leverages information from both cis element and local sequence to perform context-specific functions. Our observations imply the importance of other cues, including protein-protein interactions and the presence of additional cofactors.

Telephone Assessment of Suicidal Risk at Prehospital Emergency Medical Services: A Direct Comparison with Face-to-Face Evaluation at Psychiatric Emergency Service.

OBJECTIVE: Assessment of suicidal risk is one of the most challenging tasks faced by health professionals, notably in emergency care. We compared telephone suicide risk assessment at prehospital Emergency Medical Services Dispatch Center (EMS-DC), with subsequent face-to-face evaluation at Psychiatric Emergency Service (PES), using French national Risk-Urgency-Danger standards (RUD). METHOD: Data were collected for all suicidal adult patients (N = 80) who were addressed by EMS-DC to PES between December 2018 and August 2019 and benefited from RUD assessment at both services. Suicidal risk was given a score of 1, 2, 3 or 4, in order of severity. RESULTS: Mean of the differences between the RUD score at EMS-DC and PES was -0.825 (SD = 1.19), and was found to be significant (p < 0.01). The average time between RUD assessments was 420 min (SD = 448) and was negatively correlated with the difference in the RUD score (r = -0.295, p = 0.008). Associated suicide attempt increased the odds of a decrease in the RUD score (OR = 2.989; 95% CI = 1.141-8.069; p < 0.05). CONCLUSIONS: Telephone evaluation of suicidal risk using RUD at EMS-DC yielded moderately higher scores than those obtained by a subsequent face-to face evaluation at PES, with this difference partially explained by the time between assessments, and by clinical and contextual factors.

Knowledge updating in real-world estimation: Connecting hindsight bias and seeding effects.

When people estimate the quantities of objects (e.g., country populations), are then presented with the objects' actual quantities, and subsequently asked to remember their initial estimates, responses are often distorted towards the actual quantities. This hindsight bias-traditionally considered to reflect a cognitive error-has more recently been proposed to result from adaptive knowledge updating. But how to conceptualize such knowledge-updating processes and their potentially beneficial consequences? Here, we provide a framework that conceptualizes knowledge updating in the context of hindsight bias in real-world estimation by connecting it with research on seeding effects-improvements in people's estimation accuracy after exposure to numerical facts. This integrative perspective highlights a previously neglected facet of knowledge updating, namely, recalibration of metric domain knowledge, which can be expected to lead to transfer learning and thus improve estimation for objects from a domain more generally. We develop an experimental paradigm to investigate the association of hindsight bias with improved estimation accuracy. In Experiment 1, we demonstrate that the classical approach to induce hindsight bias indeed produces transfer learning. In Experiment 2, we provide evidence for the novel prediction that hindsight bias can be triggered via transfer learning; this establishes a direct link from knowledge updating to hindsight bias. Our work integrates two prominent but previously unconnected research programs on the effects of knowledge updating in real-world estimation and supports the notion that hindsight bias is driven by adaptive learning processes. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The Impact of the COVID-19 Pandemic on the Experiences and Operations of Sponsors of the Summer Food Service Program in Maryland, USA: A Multiphase Mixed Methods Study.

During the COVID-19 pandemic, the Summer Food Service Program (SFSP) was allowed to operate in untraditional non-summer months to ensure children did not lose access to free and reduced-priced nutritious meals when schools were mandated to close in the United States. This study assessed the impact of the pandemic on the operations and experiences of Summer Food Service Program (SFSP) sponsors in the state of Maryland during the COVID-19 pandemic in 2020 (Phase I) and 2021 (Phase II). This study used a multiphase explanatory sequential mixed methods design with qualitative prioritization. Maryland SFSP sponsors completed an online survey (Phase I: n = 27, Phase II: n = 30), and semi-structured in-depth interviews were conducted with a subset of sponsors who completed the survey (Phase I: n = 12, Phase II: n = 7). Inductive and deductive analyses were used for qualitative data, and descriptive statistics were used for quantitative data. The COVID-19 pandemic caused SFSP sponsors to change their operations. Sponsors were primarily concerned about staff safety/burnout and decreased participation. Sponsors perceived waivers implemented by the United States Department of Agriculture to be crucial in enabling them to serve meals to children during the pandemic. The findings from our study support advocacy efforts to permanently implement waivers and provide free school meals for all children.

Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients.

Introduction: Acute kidney injury (AKI) is frequently observed in patients with COVID-19 admitted to intensive care units (ICUs). Observational studies suggest that cardiovascular comorbidities and mechanical ventilation (MV) are the most important risk factors for AKI. However, no studies have investigated the renal impact of longitudinal covariates such as drug treatments, biological variations, and/or MV parameters. Methods: We performed a monocentric, prospective, longitudinal analysis to identify the dynamic risk factors for AKI in ICU patients with severe COVID-19. Results: Seventy-seven patients were included in our study (median age: 63 [interquartile range, IQR: 53-73] years; 58 (75%) men). Acute kidney injury was detected in 28 (36.3%) patients and occurred at a median time of 3 [IQR: 2-6] days after ICU admission. Multivariate Cox cause-specific time-dependent analysis identified a history of hypertension (cause-specific hazard (CSH) = 2.46 [95% confidence interval, CI: 1.04-5.84]; P = .04), a high hemodynamic Sequential Organ Failure Assessment score (CSH = 1.63 [95% CI: 1.23-2.16]; P < .001), and elevated Paco2 (CSH = 1.2 [95%CI: 1.04-1.39] per 5 mm Hg increase in Pco2; P = .02) as independent risk factors for AKI. Concerning the MV parameters, positive end-expiratory pressure (CSH = 1.11 [95% CI: 1.01-1.23] per 1 cm H2O increase; P = .04) and the use of neuromuscular blockade (CSH = 2.96 [95% CI: 1.22-7.18]; P = .02) were associated with renal outcome only in univariate analysis but not after adjustment. Conclusion: Acute kidney injury is frequent in patients with severe COVID-19 and is associated with a history of hypertension, the presence of hemodynamic failure, and increased Pco2. Further studies are necessary to evaluate the impact of hypercapnia on increasing the effects of ischemia, particularly in the most at-risk vascular situations.

Introduction: L'insuffisance rénale aiguë (IRA) est fréquemment observée chez les patients atteints de COVID-19 admis dans les unités de soins intensifs (USI). Des études observationnelles suggèrent que les comorbidités cardiovasculaires et la ventilation mécanique (VM) seraient les plus importants facteurs de risque de l'IRA. Aucune étude n'a cependant examiné l'impact sur la fonction rénale de covariables longitudinales telles que les traitements médicamenteux, les variations biologiques et/ou les paramètres de la VM. Méthodologie: Nous avons procédé à une analyse prospective et longitudinale dans un seul centre hospitalier afin d'identifier les facteurs de risque dynamiques de l'IRA chez les patients hospitalisés aux USI en raison d'une forme grave de la COVID-19. Résultats: Soixante-dix-sept patients ont été inclus dans notre étude (75 % d'hommes [n=58]; âge médian: 63 ans [ÉIQ: 53-73]). L'IRA a été détectée chez 28 patients (36,3 %) et est survenue dans un délai médian de 3 jours (ÉIQ: 2-6 jours) après l'admission à l'USI. Une analyse de Cox multivariée, spécifique à la cause et tenant compte du temps, a permis de dégager les éléments suivants comme étant des facteurs de risque indépendants pour l'IRA: des antécédents d'hypertension (probabilité par cause [PPC]=2,46 [IC 95 %: 1,04-5,84]; p=0,04), un score SOFA hémodynamique élevé (PPC=1,63 [IC 95 %: 1,23-2,16]; p<0,001) et une concentration élevée de PaCO2 (PPC=1,2 [IC 95 %: 1,04-1,39] pour chaque augmentation de 5 mmHg de pCO2; p = 0,02). En ce qui concerne les paramètres de la VM, une pression expiratoire positive (PPC=1,11 [IC 95 %: 1,01-1,23] pour chaque augmentation de 1 cm H2O; p = 0,04) et l'utilisation d'un bloc neuromusculaire (PPC=2,96 [IC 95 %: 1,22-7,18]; p=0,02) ont été associés à l'IRA dans l'analyse univariée seulement, et non après ajustement. Conclusion: L'IRA est fréquente chez les patients atteints d'une forme grave de COVID-19 et elle est associé à des antécédents d'hypertension, à la présence d'une instabilité hémodynamique et à une augmentation de la pCO2. D'autres études sont nécessaires pour évaluer l'impact de l'hypercapnie sur l'augmentation des effets de l'ischémie, en particulier dans les situations vasculaires les plus à risque.

Single-cell transcriptomics reveal extracellular vesicles secretion with a cardiomyocyte proteostasis signature during pathological remodeling.

Aberrant Wnt activation has been reported in failing cardiomyocytes. Here we present single cell transcriptome profiling of hearts with inducible cardiomyocyte-specific Wnt activation (ß-catΔex3) as well as with compensatory and failing hypertrophic remodeling. We show that functional enrichment analysis points to an involvement of extracellular vesicles (EVs) related processes in hearts of ß-catΔex3 mice. A proteomic analysis of in vivo cardiac derived EVs from ß-catΔex3 hearts has identified differentially enriched proteins involving 20 S proteasome constitutes, protein quality control (PQC), chaperones and associated cardiac proteins including α-Crystallin B (CRYAB) and sarcomeric components. The hypertrophic model confirms that cardiomyocytes reacted with an acute early transcriptional upregulation of exosome biogenesis processes and chaperones transcripts including CRYAB, which is ameliorated in advanced remodeling. Finally, human induced pluripotent stem cells (iPSC)-derived cardiomyocytes subjected to pharmacological Wnt activation recapitulated the increased expression of exosomal markers, CRYAB accumulation and increased PQC signaling. These findings reveal that secretion of EVs with a proteostasis signature contributes to early patho-physiological adaptation of cardiomyocytes, which may serve as a read-out of disease progression and can be used for monitoring cellular remodeling in vivo with a possible diagnostic and prognostic role in the future.

Studies on the Reaction of Dietary Methylglyoxal and Creatine during Simulated Gastrointestinal Digestion and in Human Volunteers.

The reactive 1,2-dicarbonyl compound methylglyoxal (MGO) is consumed with food and its concentrations decrease during digestion. In the present paper, the reaction of MGO with creatine, arginine, and lysine during simulated digestion, and its reaction with creatine during the digestion in human volunteers, was studied. Therefore, simulated digestion experiments with a gastric and an intestinal phase were performed. Additionally, an intervention study with 12 subjects consuming MGO-containing Manuka honey and creatine simultaneously or separately was conducted. Derivatization with o-phenylenediamine and HPLC-UV was used to measure MGO, while creatine and glycated amino compounds were analyzed via HPLC-MS/MS. We show that MGO quickly reacts with creatine and arginine, but not lysine, during simulated digestion. Creatine reacts with 56% of MGO to form the hydroimidazolone MG-HCr, and arginine reacted with 4% of MGO to form the hydroimidazolone MG-H1. In the intervention study, urinary MG-HCr excretion is higher in subjects who consumed MGO and creatine simultaneously compared to subjects who ingested the substances separately. This demonstrates that the 1,2-dicarbonyl compound MGO reacts with amino compounds during human digestion, and glycated adducts are formed. These contribute to dietary glycation products consumed, and should be considered in studies investigating their physiological consequences.

Microscopic and biochemical monitoring of endosomal trafficking and extracellular vesicle secretion in an endogenous in vivo model.

Extracellular vesicle (EV) secretion enables cell-cell communication in multicellular organisms. During development, EV secretion and the specific loading of signalling factors in EVs contributes to organ development and tissue differentiation. Here, we present an in vivo model to study EV secretion using the fat body and the haemolymph of the fruit fly, Drosophila melanogaster. The system makes use of tissue-specific EV labelling and is amenable to genetic modification by RNAi. This allows the unique combination of microscopic visualisation of EVs in different organs and quantitative biochemical purification to study how EVs are generated within the cells and which factors regulate their secretion in vivo. Characterisation of the system revealed that secretion of EVs from the fat body is mainly regulated by Rab11 and Rab35, highlighting the importance of recycling Rab GTPase family members for EV secretion. We furthermore discovered a so far unknown function of Rab14 along with the kinesin Klp98A in EV biogenesis and secretion.

Transcriptional Effects of Candidate COVID-19 Treatments on Cardiac Myocytes.

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) has emerged as a major cause of morbidity and mortality worldwide, placing unprecedented pressure on healthcare. Cardiomyopathy is described in patients with severe COVID-19 and increasing evidence suggests that cardiovascular involvement portends a high mortality. To facilitate fast development of antiviral interventions, drugs initially developed to treat other diseases are currently being repurposed as COVID-19 treatments. While it has been shown that SARS-CoV-2 invades cells through the angiotensin-converting enzyme 2 receptor (ACE2), the effect of drugs currently repurposed to treat COVID-19 on the heart requires further investigation. Methods: Human induced pluripotent stem cell-derived cardiac myocytes (hiPSC-CMs) were treated with five repurposed drugs (remdesivir, lopinavir/ritonavir, lopinavir/ritonavir/interferon beta (INF-ß), hydroxychloroquine, and chloroquine) and compared with DMSO controls. Transcriptional profiling was performed to identify global changes in gene expression programs. Results: RNA sequencing of hiPSC-CMs revealed significant changes in gene programs related to calcium handling and the endoplasmic reticulum stress response, most prominently for lopinavir/ritonavir and lopinavir/ritonavir/interferon-beta. The results of the differential gene expression analysis are available for interactive access at https://covid19drugs.jakobilab.org. Conclusion: Transcriptional profiling in hiPSC-CMs treated with COVID-19 drugs identified unfavorable changes with lopinavir/ritonavir and lopinavir/ritonavir/INF-ß in key cardiac gene programs that may negatively affect heart function.

Serving Summer Meals During the COVID-19 Pandemic: A Case Study of 2 Summer Food Service Program Sponsors in Maryland.

BACKGROUND: The Summer Food Service Program (SFSP) provides free and nutritious meals to children under age 18 during out-of-school times. During the COVID-19 pandemic, Maryland sponsors served over 9.5 million meals to children through an expanded version of the SFSP. This study aimed to explore and compare the factors that enabled 2 SFSP sponsors in Maryland to dramatically increase meals distribution during the pandemic. METHODS: Sponsors were selected based on their responses in the larger study and demographic characteristics of the area in which they served. Semi-structured in-depth interviews were conducted over Zoom-4 interviews with Sponsor A (3 interviews with the sponsor, 1 interview with their vendor) and 1 interview with Sponsor B. Qualitative data were analyzed inductively and deductively. Participation data from 2019 and 2020 were obtained from the Maryland State Department of Education and analyzed. RESULTS: Despite their differences in organization type and geographic region, they identified similar facilitators to their success-communication with the community and utilization of the United States Department of Agriculture-issued waivers. CONCLUSIONS: Strengthening community communication networks and permanently integrating more flexibility into regulation of the SFSP may increase meals participation during future out-of-school times.

Subcortical Brain Development in Autism and Fragile X Syndrome: Evidence for Dynamic, Age- and Disorder-Specific Trajectories in Infancy.

OBJECTIVE: Previous research has demonstrated that the amygdala is enlarged in children with autism spectrum disorder (ASD). However, the precise onset of this enlargement during infancy, how it relates to later diagnostic behaviors, whether the timing of enlargement in infancy is specific to the amygdala, and whether it is specific to ASD (or present in other neurodevelopmental disorders, such as fragile X syndrome) are all unknown. METHODS: Longitudinal MRIs were acquired at 6-24 months of age in 29 infants with fragile X syndrome, 58 infants at high likelihood for ASD who were later diagnosed with ASD, 212 high-likelihood infants not diagnosed with ASD, and 109 control infants (1,099 total scans). RESULTS: Infants who developed ASD had typically sized amygdala volumes at 6 months, but exhibited significantly faster amygdala growth between 6 and 24 months, such that by 12 months the ASD group had significantly larger amygdala volume (Cohen's d=0.56) compared with all other groups. Amygdala growth rate between 6 and 12 months was significantly associated with greater social deficits at 24 months when the infants were diagnosed with ASD. Infants with fragile X syndrome had a persistent and significantly enlarged caudate volume at all ages between 6 and 24 months (d=2.12), compared with all other groups, which was significantly associated with greater repetitive behaviors. CONCLUSIONS: This is the first MRI study comparing fragile X syndrome and ASD in infancy, demonstrating strikingly different patterns of brain and behavior development. Fragile X syndrome-related changes were present from 6 months of age, whereas ASD-related changes unfolded over the first 2 years of life, starting with no detectable group differences at 6 months. Increased amygdala growth rate between 6 and 12 months occurs prior to social deficits and well before diagnosis. This gradual onset of brain and behavior changes in ASD, but not fragile X syndrome, suggests an age- and disorder-specific pattern of cascading brain changes preceding autism diagnosis.

Neutral sphingomyelinase 2 controls exosome secretion by counteracting V-ATPase-mediated endosome acidification.

During endosome maturation, neutral sphingomyelinase 2 (nSMase2, encoded by SMPD3) is involved in budding of intraluminal vesicles (ILVs) into late endosomes or multivesicular bodies (MVBs). Fusion of these with the plasma membrane results in secretion of exosomes or small extracellular vesicles (sEVs). Here, we report that nSMase2 activity controls sEV secretion through modulation of vacuolar H+-ATPase (V-ATPase) activity. Specifically, we show that nSMase2 inhibition induces V-ATPase complex assembly that drives MVB lumen acidification and consequently reduces sEV secretion. Conversely, we further demonstrate that stimulating nSMase2 activity with the inflammatory cytokine TNFα (also known as TNF) decreases acidification and increases sEV secretion. Thus, we find that nSMase2 activity affects MVB membrane lipid composition to counteract V-ATPase-mediated endosome acidification, thereby shifting MVB fate towards sEV secretion. This article has an associated First Person interview with the first author of the paper.

Older and younger adults' hindsight bias after positive and negative outcomes.

After learning about facts or outcomes of events, people overestimate in hindsight what they knew in foresight. Prior research has shown that this hindsight bias is more pronounced in older than in younger adults. However, this robust finding is based primarily on a specific paradigm that requires generating and recalling numerical judgments to general knowledge questions that deal with emotionally neutral content. As older and younger adults tend to process positive and negative information differently, they might also show differences in hindsight bias after positive and negative outcomes. Furthermore, hindsight bias can manifest itself as a bias in memory for prior given judgments, but also as retrospective impressions of inevitability and foreseeability. Currently, there is no research on age differences in all three manifestations of hindsight bias. In this study, younger (N = 46, 18-30 years) and older adults (N = 45, 64-90 years) listened to everyday-life scenarios that ended positively or negatively, recalled the expectation they previously held about the outcome (to measure the memory component of hindsight bias), and rated each outcome's foreseeability and inevitability. Compared with younger adults, older adults recalled their prior expectations as closer to the actual outcomes (i.e., they showed a larger memory component of hindsight bias), and this age difference was more pronounced for negative than for positive outcomes. Inevitability and foreseeability impressions, however, did not differ between the age groups. Thus, there are age differences in hindsight bias after positive and negative outcomes, but only with regard to memory for prior judgments.

The Impact of Waivers on Summer Meal Participation in Maryland.

BACKGROUND: The Summer Food Service Program (SFSP) is a federally funded program that serves free, nutritious meals during the summer months. In 2019, 6 federal waivers that previously helped sponsors serve meals were rescinded. The purpose of this mixed methods study was to assess the impact of the waiver rescission on the experiences of SFSP sponsors in Maryland. METHODS: This study analyzed responses from Maryland SFSP sponsors in a quantitative online survey and linked meal participation data for 2018 and 2019 (n = 29) and in-depth interviews (n = 11) about their experiences serving summer meals. RESULTS: Most respondents reported that the waiver rescission significantly impacted their experience serving meals, including increases in workload, spending and staffing; reductions in meal types (eg, breakfast); fewer meals served; and changing closed sites to open. Sponsors expressed desire for the state to apply for waivers on behalf of all SFSP sponsors in future years. CONCLUSION: The federal rescission of USDA summer meals waivers created substantial barriers for sponsors. To address the issues created by policy decisions, school food authorities and other SFSP should continue to work with researchers and antihunger advocates to share their experiences in order to shape state programs and policies.

Extracellular WNTs: Trafficking, Exosomes, and Ligand-Receptor Interaction.

WNT signaling is a key developmental pathway in tissue organization. A recent focus of research is the secretion of WNT proteins from source cells. Research over the past decade on how WNTs are produced and released into the extracellular space has unravelled very specific control mechanisms in the early secretory pathway, specialized trafficking routes, and redundant forms of packaging for delivery to target cells. In this review I discuss the findings that WNT proteins have been found on extracellular vesicles (EVs) such as exosomes and possible functional implications. There is an ongoing debate in the WNT signaling field whether EV are relevant in vivo and can fulfill specific functions, also fueled by the general preconception of EV secretion as cellular garbage disposal. As part of the EV research community, I want to give an overview of what we know and don't know about WNT secretion on EVs and offer a more unifying model that can explain current discrepancies in observations regarding WNT secretion.