Racial disparities in rates of invasiveness of resected intraductal papillary mucinous neoplasms in the United States.

BACKGROUND: Racial and ethnic disparities have been observed in the multidisciplinary management of pancreatic ductal adenocarcinoma. Intraductal papillary mucinous neoplasm is the most common identifiable precursor to pancreatic ductal adenocarcinoma, where early surgical intervention before the development of an invasive intraductal papillary mucinous neoplasm improves survival. The association of race/ethnicity with the risk of identifying invasive intraductal papillary mucinous neoplasms during resection has not been previously defined. METHODS: The American College of Surgeons National Quality Improvement Program targeted pancreatectomy database (2014-2021) was queried for patients with race/ethnicity data who underwent resection of an intraductal papillary mucinous neoplasm. Backward Wald logistic regression modeling (P ≤ 0.05 for entry; P > .10 for removal) was used to identify independent predictors of invasion. RESULTS: A total of 4,505 cases of resected intraductal papillary mucinous neoplasms were identified, with 923 (20.5%) demonstrating invasive intraductal papillary mucinous neoplasms. The cohort of individuals other than non-Hispanic Whites were significantly more likely to have invasive intraductal papillary mucinous neoplasms (White, 19.9%; Black, 24.2%; Asian, 23.7%; Hispanic, 22.6%; P = .026). Such disparity could not be explained by greater comorbidity, as non-White patients were significantly younger (age <65 years: 41.7% vs 33.2%, P < .001) and had better physical status (American Society of Anesthesiologists score ≤2: 28.8% vs 25.2%, P = .053). After controlling for clinicodemographic variables, being an individual of race/ethnicity other than White was independently associated with higher odds of invasive intraductal papillary mucinous neoplasms (odds ratio, 1.280; 95% confidence interval, 1.046-1.566; P = .017). No differences in postoperative morbidity were observed. CONCLUSION: In a national cohort of patients with resected intraductal papillary mucinous neoplasms, individuals who identified as being of race/ethnicity other than White were significantly more likely to have invasive intraductal papillary mucinous neoplasms during surgical resection.

Association between SMAD4 Mutations and GATA6 Expression in Paired Pancreatic Ductal Adenocarcinoma Tumor Specimens: Data from Two Independent Molecularly-Characterized Cohorts.

Several molecular biomarkers have been identified to guide induction treatment selection for localized pancreatic ductal adenocarcinoma (PDAC). SMAD4 alterations and low GATA6 expression/modified "Moffitt" basal-like phenotype have each been associated with inferior survival uniquely for patients receiving 5-FU-based therapies. SMAD4 may directly regulate the expression of GATA6 in PDAC, pointing to a common predictive biomarker. To evaluate the relationship between SMAD4 mutations and GATA6 expression in human PDAC tumors, patients with paired SMAD4 mutation and GATA6 mRNA expression data in the TCGA and CPTAC were identified. In 321 patients (TCGA: n = 180; CPTAC: n = 141), the rate of SMAD4 alterations was 26.8%. The rate of SMAD4 alteration did not vary per tertile of normalized GATA6 expression (TCGA: p = 0.928; CPTAC: p = 0.828). In the TCGA, SMAD4 alterations and the basal-like phenotype were each associated with worse survival (log rank p = 0.077 and p = 0.080, respectively), but their combined presence did not identify a subset with uniquely inferior survival (p = 0.943). In the CPTAC, the basal-like phenotype was associated with significantly worse survival (p < 0.001), but the prognostic value was not influenced by the combined presence of SMAD4 alterations (p = 0.960). SMAD4 alterations were not associated with poor clinico-pathological features such as poor tumor grade, advanced tumor stage, positive lymphovascular invasion (LVI), or positive perineural invasion (PNI), compared with SMAD4-wildtype. Given that SMAD4 mutations were not associated with GATA6 expression or Moffitt subtype in two independent molecularly characterized PDAC cohorts, distinct biomarker-defined clinical trials are necessary.

Neural landscape diffusion resolves conflicts between needs across time.

Animals perform flexible goal-directed behaviours to satisfy their basic physiological needs1-12. However, little is known about how unitary behaviours are chosen under conflicting needs. Here we reveal principles by which the brain resolves such conflicts between needs across time. We developed an experimental paradigm in which a hungry and thirsty mouse is given free choices between equidistant food and water. We found that mice collect need-appropriate rewards by structuring their choices into persistent bouts with stochastic transitions. High-density electrophysiological recordings during this behaviour revealed distributed single neuron and neuronal population correlates of a persistent internal goal state guiding future choices of the mouse. We captured these phenomena with a mathematical model describing a global need state that noisily diffuses across a shifting energy landscape. Model simulations successfully predicted behavioural and neural data, including population neural dynamics before choice transitions and in response to optogenetic thirst stimulation. These results provide a general framework for resolving conflicts between needs across time, rooted in the emergent properties of need-dependent state persistence and noise-driven shifts between behavioural goals.

Association between N-Terminal Pyrenes Stabilizes the Collagen Triple Helix.

Collagen model peptides featuring the fluorophore pyrene at their N-termini have been synthesized, and their thermal denaturation has been examined using circular dichroism (CD) and fluorescence spectroscopies. Flanking the (Pro-Hyp-Gly)7 core of the peptide monomers at positions 1 and/or 23 in the primary sequence, Lys residues were introduced to ensure water solubility. Triple helices derived from such peptides show a broad excimer emission at ∼480 nm, indicative of interaction between the pyrene units. CD experiments show that the fluorophores enhance helix stability primarily through entropic effects. Unfolding temperatures (Tm) increase by up to 7 °C for systems with N-terminal lysine residues and by up to 21 °C for systems in which the first-position Lys is replaced by Ala. Tm values derived from fluorescence measurements (at 50 µM) typically lie within ∼1 °C of those obtained using CD (at 200 µM). Computational modeling in a water continuum using B3LYP-GD3 and M06-2X functionals predicts that face-to-face association of fluorophores can occur while H-bonding within the [(POG)n]3 assembly is retained. Such parallel stacking is consistent with hydrophobically driven stabilization. Labeling collagen peptides with pyrene is a synthetically simple way to promote triple helicity while providing a means to obtain Tm data on relatively dilute samples.

A transcription factor atlas of directed differentiation.

Transcription factors (TFs) regulate gene programs, thereby controlling diverse cellular processes and cell states. To comprehensively understand TFs and the programs they control, we created a barcoded library of all annotated human TF splice isoforms (>3,500) and applied it to build a TF Atlas charting expression profiles of human embryonic stem cells (hESCs) overexpressing each TF at single-cell resolution. We mapped TF-induced expression profiles to reference cell types and validated candidate TFs for generation of diverse cell types, spanning all three germ layers and trophoblasts. Targeted screens with subsets of the library allowed us to create a tailored cellular disease model and integrate mRNA expression and chromatin accessibility data to identify downstream regulators. Finally, we characterized the effects of combinatorial TF overexpression by developing and validating a strategy for predicting combinations of TFs that produce target expression profiles matching reference cell types to accelerate cellular engineering efforts.

Molecular and spatial signatures of mouse brain aging at single-cell resolution.

The diversity and complex organization of cells in the brain have hindered systematic characterization of age-related changes in its cellular and molecular architecture, limiting our ability to understand the mechanisms underlying its functional decline during aging. Here, we generated a high-resolution cell atlas of brain aging within the frontal cortex and striatum using spatially resolved single-cell transcriptomics and quantified changes in gene expression and spatial organization of major cell types in these regions over the mouse lifespan. We observed substantially more pronounced changes in cell state, gene expression, and spatial organization of non-neuronal cells over neurons. Our data revealed molecular and spatial signatures of glial and immune cell activation during aging, particularly enriched in the subcortical white matter, and identified both similarities and notable differences in cell-activation patterns induced by aging and systemic inflammatory challenge. These results provide critical insights into age-related decline and inflammation in the brain.

Cell-type-specific population dynamics of diverse reward computations.

Computational analysis of cellular activity has developed largely independently of modern transcriptomic cell typology, but integrating these approaches may be essential for full insight into cellular-level mechanisms underlying brain function and dysfunction. Applying this approach to the habenula (a structure with diverse, intermingled molecular, anatomical, and computational features), we identified encoding of reward-predictive cues and reward outcomes in distinct genetically defined neural populations, including TH+ cells and Tac1+ cells. Data from genetically targeted recordings were used to train an optimized nonlinear dynamical systems model and revealed activity dynamics consistent with a line attractor. High-density, cell-type-specific electrophysiological recordings and optogenetic perturbation provided supporting evidence for this model. Reverse-engineering predicted how Tac1+ cells might integrate reward history, which was complemented by in vivo experimentation. This integrated approach describes a process by which data-driven computational models of population activity can generate and frame actionable hypotheses for cell-type-specific investigation in biological systems.

Synthesis of redox-active fluorinated 5-hydroxytryptophans as molecular reporters for biological electron transfer.

Fluorinated 5-hydroxytryptophans (Fn-5HOWs) were synthesized in gram scale quantities and incorporated into a ß-hairpin peptide and the protein azurin. The redox-active Fn-5HOWs exhibit unique radical spectroscopic signatures that expand the function of as probes for biological electron transfer.

Differential encoding in prefrontal cortex projection neuron classes across cognitive tasks.

Single-cell transcriptomics has been widely applied to classify neurons in the mammalian brain, while systems neuroscience has historically analyzed the encoding properties of cortical neurons without considering cell types. Here we examine how specific transcriptomic types of mouse prefrontal cortex (PFC) projection neurons relate to axonal projections and encoding properties across multiple cognitive tasks. We found that most types projected to multiple targets, and most targets received projections from multiple types, except PFC→PAG (periaqueductal gray). By comparing Ca2+ activity of the molecularly homogeneous PFC→PAG type against two heterogeneous classes in several two-alternative choice tasks in freely moving mice, we found that all task-related signals assayed were qualitatively present in all examined classes. However, PAG-projecting neurons most potently encoded choice in cued tasks, whereas contralateral PFC-projecting neurons most potently encoded reward context in an uncued task. Thus, task signals are organized redundantly, but with clear quantitative biases across cells of specific molecular-anatomical characteristics.

Cerebellar nuclei evolved by repeatedly duplicating a conserved cell-type set.

How have complex brains evolved from simple circuits? Here we investigated brain region evolution at cell-type resolution in the cerebellar nuclei, the output structures of the cerebellum. Using single-nucleus RNA sequencing in mice, chickens, and humans, as well as STARmap spatial transcriptomic analysis and whole-central nervous system projection tracing, we identified a conserved cell-type set containing two region-specific excitatory neuron classes and three region-invariant inhibitory neuron classes. This set constitutes an archetypal cerebellar nucleus that was repeatedly duplicated to form new regions. The excitatory cell class that preferentially funnels information to lateral frontal cortices in mice becomes predominant in the massively expanded human lateral nucleus. Our data suggest a model of brain region evolution by duplication and divergence of entire cell-type sets.

Shoulder motion decreases as body mass increases in patients with asymptomatic shoulders.

BACKGROUND: Higher complication rates are reported after shoulder arthroplasty in obese patients. Understanding the effect of body mass index (BMI) on range of motion (ROM) in asymptomatic shoulders may be useful in evaluating clinical outcomes for patients of varying BMIs presenting with shoulder pathology. The purpose of this study is to investigate patient characteristics, in particular BMI, that may affect ROM outcomes after shoulder arthroplasty. METHODS: Individuals aged 18 years or older (mean 57.21 ± 16.27 years) were recruited with asymptomatic shoulder presentation and without history of shoulder injury. A total of 224 shoulders were grouped into 4 BMI categories, and ROM was measured with a goniometer. Analysis was performed between patient demographics and ROM. RESULTS: Analyzed continuously, BMI negatively correlated with ROM for internal rotation (IR; r = -0.511, P < .01), forward elevation (FE; r = -0.418, P < .01), and external rotation (ER; r = -0.328, P < .01). ROM analyzed by BMI category revealed a dose effect of BMI vs ROM. Obese patients demonstrated a significant decrease in IR whereas morbidly obese patients had significant decreases for all ranges: IR (r = -0.469, P < .01), FE (r = -0.452, P < .01), and ER (r = -0.33, P < .01). Normal- and overweight patients revealed no significant correlations with ROM. CONCLUSION: As BMI is negatively correlated with ROM of the asymptomatic shoulder, patients with higher BMIs may be predisposed to diminished outcomes postoperatively. These baseline correlations will allow surgeons to make postoperative expectations and anticipate poorer outcomes of shoulder ROM in obese patients.

Population-scale longitudinal mapping of COVID-19 symptoms, behaviour and testing.

Despite the widespread implementation of public health measures, coronavirus disease 2019 (COVID-19) continues to spread in the United States. To facilitate an agile response to the pandemic, we developed How We Feel, a web and mobile application that collects longitudinal self-reported survey responses on health, behaviour and demographics. Here, we report results from over 500,000 users in the United States from 2 April 2020 to 12 May 2020. We show that self-reported surveys can be used to build predictive models to identify likely COVID-19-positive individuals. We find evidence among our users for asymptomatic or presymptomatic presentation; show a variety of exposure, occupational and demographic risk factors for COVID-19 beyond symptoms; reveal factors for which users have been SARS-CoV-2 PCR tested; and highlight the temporal dynamics of symptoms and self-isolation behaviour. These results highlight the utility of collecting a diverse set of symptomatic, demographic, exposure and behavioural self-reported data to fight the COVID-19 pandemic.

Population-scale Longitudinal Mapping of COVID-19 Symptoms, Behavior, and Testing Identifies Contributors to Continued Disease Spread in the United States.

Despite social distancing and shelter-in-place policies, COVID-19 continues to spread in the United States. A lack of timely information about factors influencing COVID-19 spread and testing has hampered agile responses to the pandemic. We developed How We Feel, an extensible web and mobile application that aggregates self-reported survey responses, to fill gaps in the collection of COVID-19-related data. How We Feel collects longitudinal and geographically localized information on users' health, behavior, and demographics. Here we report results from over 500,000 users in the United States from April 2, 2020 to May 12, 2020. We show that self- reported surveys can be used to build predictive models of COVID-19 test results, which may aid in identification of likely COVID-19 positive individuals. We find evidence among our users for asymptomatic or presymptomatic presentation, as well as for household and community exposure, occupation, and demographics being strong risk factors for COVID-19. We further reveal factors for which users have been SARS-CoV-2 PCR tested, as well as the temporal dynamics of self- reported symptoms and self-isolation behavior in positive and negative users. These results highlight the utility of collecting a diverse set of symptomatic, demographic, and behavioral self- reported data to fight the COVID-19 pandemic.

Publisher Correction: Building an international consortium for tracking coronavirus health status.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cortical Observation by Synchronous Multifocal Optical Sampling Reveals Widespread Population Encoding of Actions.

To advance the measurement of distributed neuronal population representations of targeted motor actions on single trials, we developed an optical method (COSMOS) for tracking neural activity in a largely uncharacterized spatiotemporal regime. COSMOS allowed simultaneous recording of neural dynamics at ∼30 Hz from over a thousand near-cellular resolution neuronal sources spread across the entire dorsal neocortex of awake, behaving mice during a three-option lick-to-target task. We identified spatially distributed neuronal population representations spanning the dorsal cortex that precisely encoded ongoing motor actions on single trials. Neuronal correlations measured at video rate using unaveraged, whole-session data had localized spatial structure, whereas trial-averaged data exhibited widespread correlations. Separable modes of neural activity encoded history-guided motor plans, with similar population dynamics in individual areas throughout cortex. These initial experiments illustrate how COSMOS enables investigation of large-scale cortical dynamics and that information about motor actions is widely shared between areas, potentially underlying distributed computations.

Side-Chain Protonation States of a Fluorescent Arginine.

An arginine derivative with a fluorescent side-chain, Boc-Arg(Nap)-OH, was prepared by palladium(0)-catalyzed coupling of Boc-Arg-OH with a 4-bromonaphthalimide. The presence of the fluorophore lowers the pKa of the side-chain guanidinium group by several orders of magnitude, to 9.0 (±0.1), allowing the derivative to access an electrically neutral protonation state that is not generally available to arginine itself. Computational modeling (DFT) predicts that protonation takes place at the side-chain C═N atom that bears the fluorophore. Calculated electronic absorptions for the protonated (356 nm) and neutral species (440 nm) are in good agreement with experiment. When irradiated with light, excited-state proton transfer (ESPT) occurs from cationic side-chains to suitably basic solvents, resulting in fluorescence emission from the neutral species. Arg(Nap) can be incorporated into peptides with sterically accessible N-termini using specially adapted conditions of solid-phase peptide synthesis.

Thirst regulates motivated behavior through modulation of brainwide neural population dynamics.

Physiological needs produce motivational drives, such as thirst and hunger, that regulate behaviors essential to survival. Hypothalamic neurons sense these needs and must coordinate relevant brainwide neuronal activity to produce the appropriate behavior. We studied dynamics from ~24,000 neurons in 34 brain regions during thirst-motivated choice behavior in 21 mice as they consumed water and became sated. Water-predicting sensory cues elicited activity that rapidly spread throughout the brain of thirsty animals. These dynamics were gated by a brainwide mode of population activity that encoded motivational state. After satiation, focal optogenetic activation of hypothalamic thirst-sensing neurons returned global activity to the pre-satiation state. Thus, motivational states specify initial conditions that determine how a brainwide dynamical system transforms sensory input into behavioral output.