We examine the impact of local labor market shocks and state unemployment insurance (UI) policies on student discipline in U.S. public schools. Analyzing school-level discipline data and firm-level layoffs in 23 states, we find that layoffs have little effect on discipline rates overall. However, effects differ across the UI benefit distribution. At the lowest benefit level ($265/week), a mass layoff increases out-of-school suspensions by 4.5%, with effects dissipating as UI benefits increase. Effects are consistently largest for Black students - especially in predominantly White schools - resulting in increased racial disproportionality in school discipline following layoffs in low-UI states.

Mouse embryonic stem (ES) cells are pluripotent cell lines established from the preimplantation epiblast. ES cells undergo transition from naive to formative pluripotency in defined conditions. Here, we used the Rex1-GFPd2 (RGd2) fluorescent reporter to track ES cells traversing the cell state boundary by long-term single-cell imaging (LTSCI). We saw no reporter re-expression, indicating irreversible differentiation. We observed only symmetric divisions, consistent with a simple population dynamics model. Genealogical analysis showed that transitions were highly correlated between sister cells. The collapse of naive identity was invariably abrupt but was preceded by a variable lag period. Across the population, however, exit times varied by more than 15 h. The delay in entering transition extended up to three generations. Thus, ES cell differentiation timing is not directly determined by cell cycle. We speculate that asynchronous departure from the naive state may safeguard pluripotency progression in the embryo founder population.

Naive pluripotent stem cells (PSCs) are counterparts of early epiblast in the mammalian embryo. Mouse and human naive PSCs differ in self-renewal requirements and extraembryonic lineage potency. Here, we investigated the generation of chimpanzee naive PSCs. Colonies generated by resetting or reprogramming failed to propagate. We discovered that self-renewal is enabled by inhibition of Polycomb repressive complex 2 (PRC2). Expanded cells show global transcriptome proximity to human naive PSCs and embryo pre-implantation epiblast, with shared expression of a subset of pluripotency transcription factors. Chimpanzee naive PSCs can transition to multilineage competence or can differentiate into trophectoderm and hypoblast, forming tri-lineage blastoids. They thus provide a higher primate comparative model for studying pluripotency and early embryogenesis. Genetic deletions confirm that PRC2 mediates growth arrest. Further, inhibition of PRC2 overcomes a roadblock to feeder-free propagation of human naive PSCs. Therefore, excess deposition of chromatin modification H3K27me3 is an unexpected barrier to naive PSC self-renewal.

Alzheimer's disease (AD) is a neurodegenerative disorder that lacks effective treatments and urgently requires innovative therapeutic strategies. Although stem cell therapy has demonstrated efficacy in preclinical and clinical studies, it faces challenges such as low cell survival (<5%) and uncontrolled glial differentiation. This study aims to develop a 3D-bioprinted neural patch to enhance stem cell therapy for AD. The hypothesis is that a supportive bioengineered microenvironment would improve cell integration and neuronal differentiation, leading to functional recovery. A tri-component bioink (gelatin/alginate/fibrinogen) is created with tunable printability, biocompatibility, and biodegradation, establishing functional transplantation microenvironments for a 3D-printed human induced pluripotent stem cell (hiPSC)-derived neural progenitor cell (NPC) construct as a hippocampal patch. The system (TTBT) maintains NPC survival and promotes neuronal differentiation, neurite development, and calcium signaling in vitro. In AD-like rats, these constructs improved cell retention (3.41-fold over suspensions), enhanced neuron (79.21 ± 6.67% vs 65.08 ± 7.14%) and GABAergic neuron (29.85 ± 7.69% vs 15.93 ± 10.33%) differentiation, and restored long-term potentiation (LTP) to 97.89% ± 19.84% of healthy control levels. Behavioral tests also show memory improvement, particularly in the Morris water maze. This 3D-printed therapy not only holds potential for enhancing stem cell treatments but also addresses other 3D brain defects.

Stem cell transplantation has demonstrated efficacy in treating neurological disorders by generating functional cells and secreting beneficial factors. However, challenges remain for current cell suspension injection therapy, including uncontrollable cell distribution, the potential for tumor formation, and limited ability to treat spatial defects. Therefore, implants with programmable cell development, tailored 3D structure, and functionalized biomaterials have the potential to both control cell distribution and reduce or heal spatial defects. Here, a biomimetic material system comprising gelatin, alginate, and fibrinogen has been developed for neural progenitor cell constructs using 3D printing. The resulting constructs exhibit excellent formability, stability, and developmental functions in vitro, as well as biocompatibility and integration into the hippocampus in vivo. The controllability, reproducibility, and material composition of the constructs show potential for use in personalized stem cell-based therapies for defective neurological disorders, neural development research, disease modeling, and organoid-derived intelligent systems.

Analysis of single cell transcriptomics (scRNA-seq) data is typically performed after subsetting to highly variable genes (HVGs). Here, we show that Entropy Sorting provides an alternative mathematical framework for feature selection. On synthetic datasets, continuous Entropy Sort Feature Weighting (cESFW) outperforms HVG selection in distinguishing cell-state-specific genes. We apply cESFW to six merged scRNA-seq datasets spanning human early embryo development. Without smoothing or augmenting the raw counts matrices, cESFW generates a high-resolution embedding displaying coherent developmental progression from eight-cell to post-implantation stages and delineating 15 distinct cell states. The embedding highlights sequential lineage decisions during blastocyst development, while unsupervised clustering identifies branch point populations obscured in previous analyses. The first branching region, where morula cells become specified for inner cell mass or trophectoderm, includes cells previously asserted to lack a developmental trajectory. We quantify the relatedness of different pluripotent stem cell cultures to distinct embryo cell types and identify marker genes of naïve and primed pluripotency. Finally, by revealing genes with dynamic lineage-specific expression, we provide markers for staging progression from morula to blastocyst.

As the incidence of shoulder arthroplasty continues to rise, encountering significant glenoid bone loss in the primary and revision setting is becoming a common occurrence. To effectively treat these difficult scenarios, surgeons must understand the common patterns of glenoid bone loss and be aware of the various techniques available for treatment. Understanding bone loss requires careful pre-operative evaluation with appropriate imaging and pre-operative planning software. Treatment algorithms consist of primary anatomic and reverse arthroplasty as well as the use of allograft or autograft bone grafting, augmented glenoid components, specialized surgical techniques, or custom implant designs. Ultimately, good outcomes are able to be obtained with various techniques when applied to the appropriate clinical situation.

Naïve epiblast cells in the embryo and pluripotent stem cells in vitro undergo developmental progression to a formative state competent for lineage specification. During this transition, transcription factors and chromatin are rewired to encode new functional features. Here, we examine the role of mitogen-activated protein kinase (ERK1/2) signalling in pluripotent state transition. We show that a primary consequence of ERK activation in mouse embryonic stem cells is elimination of Nanog, which precipitates breakdown of the naïve state gene regulatory network. Variability in pERK dynamics results in heterogeneous loss of Nanog and metachronous state transition. Knockdown of Nanog allows exit without ERK activation. However, transition to formative pluripotency does not proceed and cells collapse to an indeterminate identity. This outcome is due to failure to maintain expression of the central pluripotency factor Oct4. Thus, during formative transition ERK signalling both dismantles the naïve state and preserves pluripotency. These results illustrate how a single signalling pathway can both initiate and secure transition between cell states.

The discovery of mouse embryonic stem cells in 1981 transformed research in mammalian developmental biology and functional genomics. The subsequent generation of human pluripotent stem cells (PSCs) and the development of molecular reprogramming have opened unheralded avenues for drug discovery and cell replacement therapy. Here, I review the history of PSCs from the perspective that long-term self-renewal is a product of the in vitro signaling environment, rather than an intrinsic feature of embryos. I discuss the relationship between pluripotent states captured in vitro to stages of epiblast in the embryo and suggest key considerations for evaluation of PSCs. A remaining fundamental challenge is to determine whether naïve pluripotency can be propagated from the broad range of mammals by exploiting common principles in gene regulatory architecture.

Over 188 million people in the United States use a subscription video streaming service, yet digital piracy remains prevalent and costs the U.S. economy an estimated $29.2 billion annually. This paper investigates the relationship between a movie's availability on Netflix, the largest video subscription service, and intent to illegally stream the movie. We leverage a contract dispute that caused Epix (a cable network company) to move all its movies from Netflix to Hulu, representing a substantial decrease in the legal streaming availability of these movies. Using a difference-in-differences design, we find that reducing legal streaming access via the removal of Epix movies from Netflix results in a 20% increase in piracy intent relative to movies that remained on Netflix, as measured by Google search volume. This study contributes to the understanding of the substitution between legal streaming services and movie piracy and has implications for content owners deciding what platform to offer their movie on.

Human pluripotent stem cells (hPSCs) are of fundamental relevance in regenerative medicine. Naïve hPSCs hold promise to overcome some of the limitations of conventional (primed) hPSCs, including recurrent epigenetic anomalies. Naïve-to-primed transition (capacitation) follows transcriptional dynamics of human embryonic epiblast and is necessary for somatic differentiation from naïve hPSCs. We found that capacitated hPSCs are transcriptionally closer to postimplantation epiblast than conventional hPSCs. This prompted us to comprehensively study epigenetic and related transcriptional changes during capacitation. Our results show that CpG islands, gene regulatory elements, and retrotransposons are hotspots of epigenetic dynamics during capacitation and indicate possible distinct roles of specific epigenetic modifications in gene expression control between naïve and primed hPSCs. Unexpectedly, PRC2 activity appeared to be dispensable for the capacitation. We find that capacitated hPSCs acquire an epigenetic state similar to conventional hPSCs. Significantly, however, the X chromosome erosion frequently observed in conventional female hPSCs is reversed by resetting and subsequent capacitation.

BACKGROUND:Shoulder radiographs are used for evaluation and the planning of treatment of various pathologies. Making a diagnosis of these pathologies on plain radiographs occurs by recognizing the relationship of the humeral head on the registry of the glenoid. Quantification of these changes in registry does not currently exist. We hypothesize that a geometric relationship of the humeral head and the glenoid exists that is defined on an anteroposterior Grashey view radiograph by the relationship of the best-fit circle of the humeral head relative to the best-fit circle of the glenoid such that relative measurements will define the normal shoulder and the pathologic shoulder.METHODS:One hundred fifty-six shoulders were included: 53 normal shoulders, 51 with primary glenohumeral osteoarthritis (GHOA), and 52 with cuff tear arthropathy (CTA). Humeral head best-fit circle was used to define the circle of the humeral head (cHH). A glenoid best-fit circle (cG) was defined by the following rules: (1) best fit of the glenoid articular surface and (2) was limited by the acromion such that either (a) it reaches maximal interaction with the inferior surface of the acromion or (b) the perimeter of the circle is at the lateralmost point of the acromion. The relationship between cHH and cG is defined by measurement of cHH in horizontal and vertical planes relative to the glenoid circle reference. The horizontal displacement angle (HDA) measures the horizontal position of cHH relative to cG, representing the degree of medialization toward the glenoid. The vertical displacement angle (VDA) measures the vertical position of cHH relative to cG, representing the degree of superiorization toward the acromion. Angles were compared by diagnosis and sex.RESULTS:The mean HDA was 61.0° (95% confidence interval [CI] 60.3°-61.7°) in normal shoulders, 79.9° (95% CI 76.9°-82.9°) in GHOA, and 63.4° (95% CI 61.7°-65.1°) in CTA (P < .001). The mean VDA was 43.1° (95% CI 42.2°-44.0°) in normal shoulders, 40.9° (95% CI 39.9°-42.0°) in GHOA, and 59.7° (95% CI 57.6°-61.7°) in CTA (P < .001). Interobserver reliability was 0.991 (95% CI 0.94-1.0) and intraobserver reliability was 0.998 (95% CI 0.99-1.0). The geometric relationship of cHH to the glenoid circle reference was plotted for each group.CONCLUSION:A geometric relationship exists of the humeral head in reference to the glenoid circle. Together, the HDA and the VDA distinguish between a normal shoulder and those with GHOA or CTA. This suggests that this novel methodology may provide a preoperative planning tool that is easily accessible.

Single cell transcriptomics (scRNA-seq) transforms our capacity to define cell states and reveal developmental trajectories. Resolution is challenged, however, by high dimensionality and noisy data. Analysis is therefore typically performed after sub-setting to highly variable genes (HVGs). However, existing HVG selection techniques have been found to have poor agreement with one another, and tend to be biased towards highly expressed genes. Entropy sorting provides an alternative mathematical framework for feature subset selection. Here we implement continuous entropy sort feature weighting (cESFW). On synthetic datasets, cESFW outperforms HVG selection in distinguishing cell state specific genes. We apply cESFW to six merged scRNA-seq datasets spanning human early embryo development. Without smoothing or augmenting the raw counts matrices, cESFW generates a high-resolution embedding displaying coherent developmental progression from 8-cell to post-implantation stages, delineating 15 distinct cell states. The embedding highlights sequential lineage decisions during blastocyst development while unsupervised clustering identifies branch point populations. Cells previously claimed to lack a developmental trajectory reside in the first branching region where morula differentiates into Inner Cell Mass (ICM) or Trophectoderm (TE). We quantify the relatedness of pluripotent stem cell cultures to embryo cell types and identify naïve and primed marker genes conserved across culture conditions and the human embryo. Finally, by identifying genes with specifically enriched and dynamic expression during blastocyst formation, we provide markers for staging lineage progression from morula to blastocyst. Together these analyses indicate that cESFW provides the ability to reveal gene expression dynamics in scRNA-seq data that HVG selection can fail to elucidate.

The Company of Biologists' 2022 workshop on 'Cell State Transitions: Approaches, Experimental Systems and Models' brought together an international and interdisciplinary team of investigators spanning the fields of cell and developmental biology, stem cell biology, physics, mathematics and engineering to tackle the question of how cells precisely navigate between distinct identities and do so in a dynamic manner. This second edition of the workshop was organized after a successful virtual workshop on the same topic that took place in 2021.

Embryo development is a critical and fascinating stage in the life cycle of many organisms. Despite decades of research, the earliest stages of mammalian embryogenesis are still poorly understood, caused by a scarcity of high-resolution spatial and temporal data, the use of only a few model organisms, and a paucity of truly multidisciplinary approaches that combine biological research with biophysical modeling and computational simulation. Here, we explain the theoretical frameworks and biophysical processes that are best suited to modeling the early mammalian embryo, review a comprehensive list of previous models, and discuss the most promising avenues for future work.

The laboratory culture of human stem cells seeks to capture a cellular state as an in vitro surrogate of a biological system. For the results and outputs from this research to be accurate, meaningful, and durable, standards that ensure reproducibility and reliability of the data should be applied. Although such standards have been previously proposed for repositories and distribution centers, no widely accepted best practices exist for laboratory research with human pluripotent and tissue stem cells. To fill that void, the International Society for Stem Cell Research has developed a set of recommendations, including reporting criteria, for scientists in basic research laboratories. These criteria are designed to be technically and financially feasible and, when implemented, enhance the reproducibility and rigor of stem cell research.

ABSTRACT Naïve epiblast cells in the embryo and pluripotent stem cells in vitro undergo developmental progression to a formative state competent for lineage specification. During this transition, transcription factors and chromatin are rewired to encode new functional features. Here, we examine the role of mitogen-activated protein kinase (ERK1/2) signalling in pluripotent state transition. We show that a primary consequence of ERK activation in mouse embryonic stem cells is elimination of Nanog, precipitating breakdown of the naïve state gene regulatory network. Cell variability in pERK dynamics results in metachronous down-regulation of Nanog and naïve state exit. Knockdown of Nanog allows exit without ERK activation. However, transition to formative pluripotency does not proceed and cells collapse to an indeterminate identity. This failure is attributable to loss of expression of the central pluripotency factor Oct4. Thus, during formative transition ERK signalling both dismantles the naïve state and preserves pluripotency. These results illustrate that a single signalling pathway can both drive exit from a developmental state and safeguard progression to the successor state.

A major challenge in single-cell gene expression analysis is to discern meaningful cellular heterogeneity from technical or biological noise. To address this challenge, we present entropy sorting (ES), a mathematical framework that distinguishes genes indicative of cell identity. ES achieves this in an unsupervised manner by quantifying if observed correlations between features are more likely to have occurred due to random chance versus a dependent relationship, without the need for any user-defined significance threshold. On synthetic data, we demonstrate the removal of noisy signals to reveal a higher resolution of gene expression patterns than commonly used feature selection methods. We then apply ES to human pre-implantation embryo single-cell RNA sequencing (scRNA-seq) data. Previous studies failed to unambiguously identify early inner cell mass (ICM), suggesting that the human embryo may diverge from the mouse paradigm. In contrast, ES resolves the ICM and reveals sequential lineage bifurcations as in the classical model. ES thus provides a powerful approach for maximizing information extraction from high-dimensional datasets such as scRNA-seq data.

ABSTRACT Propagation of human naïve pluripotent stem cells (nPSCs) relies on the inhibition of MEK/ERK signalling. However, MEK/ERK inhibition also promotes differentiation into trophectoderm (TE). Therefore, robust self-renewal requires suppression of TE fate. Tankyrase inhibition using XAV939 has been shown to stabilise human nPSCs and is implicated in TE suppression. Here, we dissect the mechanism of this effect. Tankyrase inhibition is known to block canonical Wnt/β-catenin signalling. However, we show that nPSCs depleted of β-catenin remain dependent on XAV939. Rather than inhibiting Wnt, we found that XAV939 prevents TE induction by reducing activation of YAP, a co-factor of TE-inducing TEAD transcription factors. Tankyrase inhibition stabilises angiomotin, which limits nuclear accumulation of YAP. Upon deletion of angiomotin-family members AMOT and AMOTL2, nuclear YAP increases and XAV939 fails to prevent TE induction. Expression of constitutively active YAP similarly precipitates TE differentiation. Conversely, nPSCs lacking YAP1 or its paralog TAZ (WWTR1) resist TE differentiation and self-renewal efficiently without XAV939. These findings explain the distinct requirement for tankyrase inhibition in human but not in mouse nPSCs and highlight the pivotal role of YAP activity in human naïve pluripotency and TE differentiation. This article has an associated ‘The people behind the papers’ interview.