Spatial enhancer activation influences inhibitory neuron identity during mouse embryonic development.

The mammalian telencephalon contains distinct GABAergic projection neuron and interneuron types, originating in the germinal zone of the embryonic basal ganglia. How genetic information in the germinal zone determines cell types is unclear. Here we use a combination of in vivo CRISPR perturbation, lineage tracing and ChIP-sequencing analyses and show that the transcription factor MEIS2 favors the development of projection neurons by binding enhancer regions in projection-neuron-specific genes during mouse embryonic development. MEIS2 requires the presence of the homeodomain transcription factor DLX5 to direct its functional activity toward the appropriate binding sites. In interneuron precursors, the transcription factor LHX6 represses the MEIS2-DLX5-dependent activation of projection-neuron-specific enhancers. Mutations of Meis2 result in decreased activation of regulatory enhancers, affecting GABAergic differentiation. We propose a differential binding model where the binding of transcription factors at cis-regulatory elements determines differential gene expression programs regulating cell fate specification in the mouse ganglionic eminence.

A patient-enriched MEIS1 coding variant causes a restless legs syndrome-like phenotype in mice.

Restless legs syndrome (RLS) is a neurological disorder characterized by uncomfortable or unpleasant sensations in the legs during rest periods. To relieve these sensations, patients move their legs, causing sleep disruption. While the pathogenesis of RLS has yet to be resolved, there is a strong genetic association with the MEIS1 gene. A missense variant in MEIS1 is enriched sevenfold in people with RLS compared to non-affected individuals. We generated a mouse line carrying this mutation (p.Arg272His/c.815G>A), referred to herein as Meis1R272H/R272H (Meis1 point mutation), to determine whether it would phenotypically resemble RLS. As women are more prone to RLS, driven partly by an increased risk of developing RLS during pregnancy, we focused on female homozygous mice. We evaluated RLS-related outcomes, particularly sensorimotor behavior and sleep, in young and aged mice. Compared to noncarrier littermates, homozygous mice displayed very few differences. Significant hyperactivity occurred before the lights-on (rest) period in aged female mice, reflecting the age-dependent incidence of RLS. Sensory experiments involving tactile feedback (rotarod, wheel running, and hotplate) were only marginally different. Overall, RLS-like phenomena were not recapitulated except for the increased wake activity prior to rest. This is likely due to the focus on young mice. Nevertheless, the Meis1R272H mouse line is a potentially useful RLS model, carrying a clinically relevant variant and showing an age-dependent phenotype.

Best Case/Worst Case: protocol for a multisite randomised clinical trial of a scenario planning intervention for patients with kidney failure.

INTRODUCTION: Given the burdens of treatment and poor prognosis, older adults with kidney failure would benefit from improved decision making and palliative care to clarify goals, address symptoms, and reduce unwanted procedures. Best Case/Worst Case (BC/WC) is a communication tool that uses scenario planning to support patients' decision making. This article describes the protocol for a multisite, cluster randomised trial to test the effect of training nephrologists to use the BC/WC communication tool on patient receipt of palliative care, and quality of life and communication. METHODS AND ANALYSIS: We are enrolling attending nephrologists, at 10 study sites in the USA, who see outpatients with advanced chronic kidney disease considering dialysis. We aim to enrol 320 patients with an estimated glomerular filtration rate of ≤24 mL/min/1.73 m2 who are age 60 and older and have a predicted survival of 18 months or less. Nephrologists will be randomised in a 1:1 ratio to receive training to use the communication tool (intervention) at study initiation or after study completion (wait-list control). Patients in the intervention group will receive care from a nephrologist trained to use the BC/WC communication tool. Patients in the control group will receive usual care. Using chart review and surveys of patients and caregivers, we will test the efficacy of the BC/WC intervention with receipt of palliative care as the primary outcome. Secondary outcomes include intensity of treatment at the end of life, the effect of the intervention on quality of communication (QOC) between nephrologists and patients (using the QOC scale), the change in quality of life (using the Functional Assessment of Chronic Illness Therapy-Palliative Care scale) and receipt of dialysis. ETHICS AND DISSEMINATION: Approvals have been granted by the Institutional Review Board at the University of Wisconsin (ID: 2022-0193), with each study site ceding review to the primary IRB. All nephrologists will be consented and given a copy of the consent form. No patients or caregivers will be recruited or consented until their nephrology provider has chosen to participate in the study. Results will be disseminated via submission for publication in a peer-reviewed journal and at national meetings. TRIAL REGISTRATION NUMBER: NCT04466865.

Discovery of mobocertinib, a new irreversible tyrosine kinase inhibitor indicated for the treatment of non-small-cell lung cancer harboring EGFR exon 20 insertion mutations.

Epidermal growth factor receptor (EGFR) is essential for normal cellular functions. Mutations of EGFR's kinase domain can cause dysregulation leading to non-small cell lung cancer (NSCLC). Exon 20 insertion (ex20ins) mutations in EGFR are one of the leading contributors to oncogenesis and confer insensitivity to most available therapeutics. Mobocertinib is a novel tyrosine kinase inhibitor (TKI) recently approved by the US FDA as a first-in-class small molecule therapeutic for EGFR ex20ins-positive NSCLC. When compared to osimertinib, a TKI indicated for the treatment of EGFR T790M-positive NSCLC, mobocertinib differs only by the presence of an additional C5-carboxylate isopropyl ester group on the middle pyrimidine core. Together with the acrylamide side chain that is responsible for irreversible inhibition, this additional C5-substituent affords mobocertinib high anticancer potency and specificity to EGFR ex20ins-positive lung cancer that is resistant to other EGFR TKIs. This review article provides an overview of the discovery of mobocertinib from osimertinib including their structure-activity relationships, mechanisms of action, preclinical pharmacology, pharmacokinetics, and clinical applications. The discovery and use of mobocertinib and other EGFR TKIs demonstrate the power of structure-based drug design and promising therapeutic outcomes of using precision medicine approaches in the management of molecularly defined tumors. Graphical abstract.

Use of e-triggers to identify diagnostic errors in the paediatric ED.

BACKGROUND: Diagnostic errors (DxEs) are an understudied source of patient harm in children rarely captured in current adverse event reporting systems. Applying electronic triggers (e-triggers) to electronic health records shows promise in identifying DxEs but has not been used in the emergency department (ED) setting. OBJECTIVES: To assess the performance of an e-trigger and subsequent manual screening for identifying probable DxEs among children with unplanned admission following a prior ED visit and to compare performance to existing incident reporting systems. DESIGN/METHODS: Retrospective single-centre cohort study of children ages 0-22 admitted within 14 days of a previous ED visit between 1 January 2018 and 31 December 2019. Subjects were identified by e-trigger, screened to identify cases where index visit and hospital discharge diagnoses were potentially related but pathophysiologically distinct, and then these screened-in cases were reviewed for DxE using the SaferDx Instrument. Cases of DxE identified by e-trigger were cross-referenced against existing institutional incident reporting systems. RESULTS: An e-trigger identified 1915 unplanned admissions (7.7% of 24 849 total admissions) with a preceding index visit. 453 (23.7%) were screened in and underwent review using SaferDx. 92 cases were classified as likely DxEs, representing 0.4% of all hospital admissions, 4.8% among those selected by e-trigger and 20.3% among those screened in for review. Half of cases were reviewed by two reviewers using SaferDx with substantial inter-rater reliability (Cohen's κ=0.65 (95% CI 0.54 to 0.75)). Six (6.5%) cases had been reported elsewhere: two to the hospital's incident reporting system and five to the ED case review team (one reported to both). CONCLUSION: An e-trigger coupled with manual screening enriched a cohort of patients at risk for DxEs. Fewer than 10% of DxEs were identified through existing surveillance systems, suggesting that they miss a large proportion of DxEs. Further study is required to identify specific clinical presentations at risk of DxEs.

Intronic elements associated with insomnia and restless legs syndrome exhibit cell-type-specific epigenetic features contributing to MEIS1 regulation.

A highly evolutionarily conserved myeloid ecotropic viral integration site 1 (MEIS1) intronic region is strongly associated with restless legs syndrome (RLS) and insomnia. To understand its regulatory function, we dissected the region by analyzing chromatin accessibility, enhancer-promoter contacts, DNA methylation and expression quantitative trait locus (eQTLs) in different human neural cell types and tissues. We observed specific activity with respect to cell type and developmental maturation, indicating a prominent role for distinct highly conserved intronic elements in forebrain inhibitory neuron differentiation. Two elements were hypomethylated in neural cells with higher MEIS1 expression, suggesting a role of enhancer demethylation in gene regulation. MEIS1 eQTLs showed a striking modular chromosomal distribution, with forebrain eQTLs clustering in intron 8/9. Clustered regularly interspersed short palindromic repeats interference targeting of individual elements in this region attenuated MEIS1 expression, revealing a complex regulatory interplay of distinct elements. In summary, we found that MEIS1 regulation is organized in a modular pattern. Disease-associated intronic regulatory elements control MEIS1 expression with cell type and maturation stage specificity, particularly in the inhibitory neuron lineage. The precise spatiotemporal activity of these elements likely contributes to the pathogenesis of insomnia and RLS.

Collagen VI Regulates Motor Circuit Plasticity and Motor Performance by Cannabinoid Modulation.

Collagen VI is a key component of muscle basement membranes, and genetic variants can cause monogenic muscular dystrophies. Conversely, human genetic studies recently implicated collagen VI in central nervous system function, with variants causing the movement disorder dystonia. To elucidate the neurophysiological role of collagen VI, we generated mice with a truncation of the dystonia-related collagen α3 VI (COL6A3) C-terminal domain (CTD). These Col6a3CTT mice showed a recessive dystonia-like phenotype in both sexes. We found that COL6A3 interacts with the cannabinoid receptor 1 (CB1R) complex in a CTD-dependent manner. Col6a3CTT mice of both sexes have impaired homeostasis of excitatory input to the basal pontine nuclei (BPN), a motor control hub with dense COL6A3 expression, consistent with deficient endocannabinoid (eCB) signaling. Aberrant synaptic input in the BPN was normalized by a CB1R agonist, and motor performance in Col6a3CTT mice of both sexes was improved by CB1R agonist treatment. Our findings identify a readily therapeutically addressable synaptic mechanism for motor control.SIGNIFICANCE STATEMENT Dystonia is a movement disorder characterized by involuntary movements. We previously identified genetic variants affecting a specific domain of the COL6A3 protein as a cause of dystonia. Here, we created mice lacking the affected domain and observed an analogous movement disorder. Using a protein interaction screen, we found that the affected COL6A3 domain mediates an interaction with the cannabinoid receptor 1 (CB1R). Concordantly, our COL6A3-deficient mice showed a deficit in synaptic plasticity linked to a deficit in cannabinoid signaling. Pharmacological cannabinoid augmentation rescued the motor impairment of the mice. Thus, cannabinoid augmentation could be a promising avenue for treating dystonia, and we have identified a possible molecular mechanism mediating this.

Proteomic profiling dataset of chemical perturbations in multiple biological backgrounds.

While gene expression profiling has traditionally been the method of choice for large-scale perturbational profiling studies, proteomics has emerged as an effective tool in this context for directly monitoring cellular responses to perturbations. We previously reported a pilot library containing 3400 profiles of multiple perturbations across diverse cellular backgrounds in the reduced-representation phosphoproteome (P100) and chromatin space (Global Chromatin Profiling, GCP). Here, we expand our original dataset to include profiles from a new set of cardiotoxic compounds and from astrocytes, an additional neural cell model, totaling 5300 proteomic signatures. We describe filtering criteria and quality control metrics used to assess and validate the technical quality and reproducibility of our data. To demonstrate the power of the library, we present two case studies where data is queried using the concept of "connectivity" to obtain biological insight. All data presented in this study have been deposited to the ProteomeXchange Consortium with identifiers PXD017458 (P100) and PXD017459 (GCP) and can be queried at https://clue.io/proteomics .

Investigation of dopaminergic signalling in Meis homeobox 1 (Meis1) deficient mice as an animal model of restless legs syndrome.

Restless legs syndrome (RLS) is a common neurological disorder in which sensorimotor symptoms lead to sleep disturbances with substantial impact on life quality. RLS is caused by a combination of genetic and environmental factors, and Meis homeobox 1 (MEIS1) was identified as the main genetic risk factor. The efficacy of dopaminergic agonists, including dopamine D2 receptor (DRD2) agonists, for treating RLS led to the hypothesis of dopaminergic impairment. However, it remains unclear whether it is directly involved in the disease aetiology and what the role of MEIS1 is considering its developmental and postnatal expression in the striatum, a critical structure in motor control. We addressed the role of MEIS1 in striatal dopaminergic signalling in Meis1+/- mice, a valid animal model of RLS, and in Meis1Drd2-/- mice carrying a somatic null mutation of Meis1 in Drd2+ neurones. Motor behaviours, pharmacological exploration of DRD2 signalling, and quantitative analyses of DRD2+ and DRD1+ expressing neurones were investigated. Although Meis1+/- mice displayed an RLS-like phenotype, including motor hyperactivity at the beginning of the rest phase, no reduction of dopaminoceptive neurones was observed in the striatum. Moreover, the null mutation of Meis1 in DRD2+ cells did not lead to RLS-like symptoms and dysfunction of the DRD2 pathway. These data indicate that MEIS1 does not modulate DRD2-dependent signalling in a cell-autonomous manner. Thus, the efficiency of D2 -like agonists may reflect the involvement of other dopaminergic receptors or normalisation of motor circuit abnormalities downstream from defects caused by MEIS1 dysfunction.

Decreased sensitivity to the anorectic effects of leptin in mice that lack a Pomc-specific neural enhancer.

Enhancer redundancy has been postulated to provide a buffer for gene expression against genetic and environmental perturbations. While work in Drosophila has identified functionally overlapping enhancers, work in mammalian models has been limited. Recently, we have identified two partially redundant enhancers, nPE1 and nPE2, that drive proopiomelanocortin gene expression in the hypothalamus. Here we demonstrate that deletion of nPE1 produces mild obesity while knockout of nPE2 has no discernible metabolic phenotypes. Additionally, we show that acute leptin administration has significant effects on nPE1 knockout mice, with food intake and body weight change significantly impacted by peripheral leptin treatment. nPE1 knockout mice became less responsive to leptin treatment over time as percent body weight change increased over 2 week exposure to peripheral leptin. Both Pomc and Agrp mRNA were not differentially affected by chronic leptin treatment however we did see a decrease in Pomc and Agrp mRNA in both nPE1 and nPE2 knockout calorie restricted mice as compared to calorie restricted PBS-treated WT mice. Collectively, these data suggest dynamic regulation of Pomc by nPE1 such that mice with nPE1 knockout become less responsive to the anorectic effects of leptin treatment over time. Our results also support our earlier findings in which nPE2 may only be critical in adult mice that lack nPE1, indicating that these neural enhancers work synergistically to influence metabolism.

Author Correction: Cas9 activates the p53 pathway and selects for p53-inactivating mutations.

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

Cas9 activates the p53 pathway and selects for p53-inactivating mutations.

Cas9 is commonly introduced into cell lines to enable CRISPR-Cas9-mediated genome editing. Here, we studied the genetic and transcriptional consequences of Cas9 expression itself. Gene expression profiling of 165 pairs of human cancer cell lines and their Cas9-expressing derivatives revealed upregulation of the p53 pathway upon introduction of Cas9, specifically in wild-type TP53 (TP53-WT) cell lines. This was confirmed at the messenger RNA and protein levels. Moreover, elevated levels of DNA repair were observed in Cas9-expressing cell lines. Genetic characterization of 42 cell line pairs showed that introduction of Cas9 can lead to the emergence and expansion of p53-inactivating mutations. This was confirmed by competition experiments in isogenic TP53-WT and TP53-null (TP53-/-) cell lines. Lastly, Cas9 was less active in TP53-WT than in TP53-mutant cell lines, and Cas9-induced p53 pathway activation affected cellular sensitivity to both genetic and chemical perturbations. These findings may have broad implications for the proper use of CRISPR-Cas9-mediated genome editing.

Creating a Palliative Care Inpatient Response Plan for COVID-19-The UW Medicine Experience.

CONTEXT: The coronavirus disease 2019 (COVID-19) pandemic is stressing health care systems throughout the world. Significant numbers of patients are being admitted to the hospital with severe illness, often in the setting of advanced age and underlying comorbidities. Therefore, palliative care is an important part of the response to this pandemic. The Seattle area and UW Medicine have been on the forefront of the pandemic in the U.S. METHODS: UW Medicine developed a strategy to implement a palliative care response for a multihospital health care system that incorporates conventional capacity, contingency capacity, and crisis capacity. The strategy was developed by our palliative care programs with input from the health care system leadership. RESULTS: In this publication, we share our multifaceted strategy to implement high-quality palliative care in the context of the COVID-19 pandemic that incorporates conventional, contingency, and crisis capacity and focuses on the areas of the hospital caring for the most patients: the emergency department, intensive care units, and acute care services. The strategy focuses on key content areas, including identifying and addressing goals of care, addressing moderate and severe symptoms, and supporting family members. CONCLUSION: Strategy planning for delivery of high-quality palliative care in the context of the COVID-19 pandemic represents an important area of need for our health care systems. We share our experiences of developing such a strategy to help other institutions conduct and adapt such strategies more quickly.

Update on KMT2B-Related Dystonia.

PURPOSE OF REVIEW: To summarize the molecular and clinical findings of KMT2B-related dystonia (DYT-KMT2B), a newly identified genetic dystonia syndrome. RECENT FINDINGS: Since first described in 2016, 66 different KMT2B-affecting variants, encompassing a set of frameshift, nonsense, splice-site, missense, and deletion mutations, have been reported in 76 patients. Most mutations are de novo and expected to mediate epigenetic dysregulation by inducing KMT2B haploinsufficiency. DYT-KMT2B is characterized phenotypically by limb-onset childhood dystonia that tends to spread progressively, resulting in generalized dystonia with cranio-cervical involvement. Co-occuring signs such as intellectual disability are frequently observed. Sustained response to deep brain stimulation (DBS), including restoration of independent ambulation, is seen in 93% (27/29) of patients. DYT-KMT2B is emerging as a prevalent monogenic dystonia. Childhood-onset dystonia presentations should prompt a search for KMT2B mutations, preferentially via next-generation-sequencing and genomic-array technologies, to enable specific counseling and treatment. Prospective multicenter studies are desirable to establish KMT2B mutational status as a DBS outcome predictor.

Role of MEIS1 in restless legs syndrome: From GWAS to functional studies in mice.

MEIS1 is a transcription factor playing an important role in the development of several organs, including central and peripheral nervous systems. A genetic locus spanning the MEIS1 coding region has been associated with the risk of RLS in genome-wide association studies, with increasing evidence that MEIS1 is the causal RLS gene. The RLS-linked genetic signal has been mapped to an intronic regulatory element within MEIS1. This element plays a role in the ganglionic eminences of the developing forebrain, with the RLS risk allele related to a reduced activation of the enhancer. This suggests that the ganglionic eminences play an important role in the development of genetic susceptibility to RLS. In addition, rare variants within MEIS1 have been shown to contribute to the disease risk. These variants were identified first in RLS families and later found in further RLS cases by targeted sequencing. Some of these variants alone are sufficient to suppress MEIS1 function in neural development, providing further evidence of the importance of neurodevelopmental processes in the pathological mechanism of MEIS1 in RLS. Heterozygous Meis1 inactivation in mice causes hyperactivity at the onset of the inactive period, consistent with human RLS. In addition, these mice revealed an effect of MEIS1 on the dopaminergic system at both the spinal and supraspinal level. More studies are needed in human genetics to determine the exact role of MEIS1 variants in the risk of RLS, as well as in functional genetics and animal studies to further elucidate the pathological mechanism of MEIS1 in RLS.

Recessive variants in ZNF142 cause a complex neurodevelopmental disorder with intellectual disability, speech impairment, seizures, and dystonia.

PURPOSE: The purpose of this study was to expand the genetic architecture of neurodevelopmental disorders, and to characterize the clinical features of a novel cohort of affected individuals with variants in ZNF142, a C2H2 domain-containing transcription factor. METHODS: Four independent research centers used exome sequencing to elucidate the genetic basis of neurodevelopmental phenotypes in four unrelated families. Following bioinformatic filtering, query of control data sets, and secondary variant confirmation, we aggregated findings using an online data sharing platform. We performed in-depth clinical phenotyping in all affected individuals. RESULTS: We identified seven affected females in four pedigrees with likely pathogenic variants in ZNF142 that segregate with recessive disease. Affected cases in three families harbor either nonsense or frameshifting likely pathogenic variants predicted to undergo nonsense mediated decay. One additional trio bears ultrarare missense variants in conserved regions of ZNF142 that are predicted to be damaging to protein function. We performed clinical comparisons across our cohort and noted consistent presence of intellectual disability and speech impairment, with variable manifestation of seizures, tremor, and dystonia. CONCLUSION: Our aggregate data support a role for ZNF142 in nervous system development and add to the emergent list of zinc finger proteins that contribute to neurocognitive disorders.

A Conceptual Framework of Palliative Care across the Continuum of Advanced Kidney Disease.

Kidney palliative care is a growing discipline within nephrology. Kidney palliative care specifically addresses the stress and burden of advanced kidney disease through the provision of expert symptom management, caregiver support, and advance care planning with the goal of optimizing quality of life for patients and families. The integration of palliative care principles is necessary to address the multidimensional impact of advanced kidney disease on patients. In particular, patients with advanced kidney disease have a high symptom burden and experience greater intensity of care at the end of life compared with other chronic serious illnesses. Currently, access to kidney palliative care is lacking, whether delivered by trained kidney care professionals or by palliative care clinicians. These barriers include a gap in training and workforce, policies limiting access to hospice and outpatient palliative care services for patients with ESKD, resistance to integrating palliative care within the nephrology community, and the misconception that palliative care is synonymous with end-of-life care. As such, addressing kidney palliative care needs on a population level will require not only access to specialized kidney palliative care initiatives, but also equipping kidney care professionals with the skills to address basic kidney palliative care needs. This article will address the role of kidney palliative care for patients with advanced kidney disease, describe models of care including primary and specialty kidney palliative care, and outline strategies to improve kidney palliative care on a provider and system level.

Muscle-induced loading as an important source of variation in craniofacial skeletal shape.

The shape of the craniofacial skeleton is constantly changing through ontogeny and reflects a balance between developmental patterning and mechanical-load-induced remodeling. Muscles are a major contributor to producing the mechanical environment that is crucial for "normal" skull development. Here, we use an F5 hybrid population of Lake Malawi cichlids to characterize the strength and types of associations between craniofacial bones and muscles. We focus on four bones/bone complexes, with different developmental origins, alongside four muscles with distinct functions. We used micro-computed tomography to extract 3D information on bones and muscles. 3D geometric morphometrics and volumetric measurements were used to characterize bone and muscle shape, respectively. Linear regressions were performed to test for associations between bone shape and muscle volume. We identified three types of associations between muscles and bones: weak, strong direct (i.e., muscles insert directly onto bone), and strong indirect (i.e., bone is influenced by muscles without a direct connection). In addition, we show that although the shape of some bones is relatively robust to muscle-induced mechanical stimulus, others appear to be highly sensitive to muscular input. Our results imply that the roles for muscular input on skeletal shape extend beyond specific points of origin or insertion and hold significant potential to influence broader patterns of craniofacial geometry. Thus, changes in the loading environment, either as a normal course of ontogeny or if an organism is exposed to a novel environment, may have pronounced effects on skeletal shape via near and far-ranging effects of muscular loading.