Itga8-Cre-mediated deletion of YAP and TAZ impairs bladder contractility with minimal inflammation and chondrogenic differentiation

A role of Yes1-associated transcriptional regulator (YAP) and WW domain-containing transcription regulator 1 (TAZ) in vascular and gastrointestinal contractility due to control of myocardin (Myocd) expression, which in turn activates contractile genes, has been demonstrated. Whether this transcriptional hierarchy applies to the urinary bladder is unclear. We found that YAP/TAZ are expressed in human detrusor myocytes and therefore exploited the Itga8-CreERT2 model for the deletion of YAP/TAZ. Recombination occurred in detrusor, and YAP/TAZ transcripts were reduced by >75%. Bladder weights were increased (by ≈22%), but histology demonstrated minimal changes in the detrusor, while arteries in the mucosa were inflamed. Real-time quantitative reverse transcription PCR (RT-qPCR) using the detrusor demonstrated reductions of Myocd (-79 ± 18%) and serum response factor (Srf) along with contractile genes. In addition, the cholinergic receptor muscarinic 2 (Chrm2) and Chrm3 were suppressed (-80 ± 23% and -80 ± 10%), whereas minute increases of Il1b and Il6 were seen. Unlike YAP/TAZ-deficient arteries, SRY (sex-determining region Y)-box 9 (Sox9) did not increase, and no chondrogenic differentiation was apparent. Reductions of smooth muscle myosin heavy chain 11 (Myh11), myosin light-chain kinase gene (Mylk), and Chrm3 were seen at the protein level. Beyond restraining the smooth muscle cell (SMC) program of gene expression, YAP/TAZ depletion silenced SMC-specific splicing, including exon 2a of Myocd. Reduced contractile differentiation was associated with weaker contraction in response to myosin phosphatase inhibition (-36%) and muscarinic activation (reduced by 53% at 0.3 µM carbachol). Finally, short-term overexpression of constitutively active YAP in human embryonic kidney 293 (HEK293) cells increased myocardin (greater than eightfold) along with archetypal target genes, but contractile genes were unaffected or reduced. YAP and TAZ thus regulate myocardin expression in the detrusor, and this is important for SMC differentiation and splicing as well as for contractility.NEW & NOTEWORTHY This study addresses the hypothesis that YAP and TAZ have an overarching role in the transcriptional hierarchy in the smooth muscle of the urinary bladder by controlling myocardin expression. Using smooth muscle-specific and inducible deletion of YAP and TAZ in adult mice, we find that YAP and TAZ control myocardin expression, contractile differentiation, smooth muscle-specific splicing, and bladder contractility. These effects are largely independent of inflammation and chondrogenic differentiation.

Vascular smooth muscle-specific YAP/TAZ deletion triggers aneurysm development in mouse aorta

Inadequate adaption to mechanical forces, including blood pressure, contributes to development of arterial aneurysms. Recent studies have pointed to a mechanoprotective role of YAP and TAZ in vascular smooth muscle cells (SMCs). Here, we identified reduced expression of YAP1 in human aortic aneurysms. Vascular SMC-specific knockouts (KOs) of YAP/TAZ were thus generated using the integrin α8-Cre (Itga8-Cre) mouse model (i8-YT-KO). i8-YT-KO mice spontaneously developed aneurysms in the abdominal aorta within 2 weeks of KO induction and in smaller arteries at later times. The vascular specificity of Itga8-Cre circumvented gastrointestinal effects. Aortic aneurysms were characterized by elastin disarray, SMC apoptosis, and accumulation of proteoglycans and immune cell populations. RNA sequencing, proteomics, and myography demonstrated decreased contractile differentiation of SMCs and impaired vascular contractility. This associated with partial loss of myocardin expression, reduced blood pressure, and edema. Mediators in the inflammatory cGAS/STING pathway were increased. A sizeable increase in SOX9, along with several direct target genes, including aggrecan (Acan), contributed to proteoglycan accumulation. This was the earliest detectable change, occurring 3 days after KO induction and before the proinflammatory transition. In conclusion, Itga8-Cre deletion of YAP and TAZ represents a rapid and spontaneous aneurysm model that recapitulates features of human abdominal aortic aneurysms.

Introducing Braining-physical exercise as adjunctive therapy in psychiatric care: a retrospective cohort study of a new method

BACKGROUND

Patients with severe mental disorders suffer from higher rates of poor somatic health and have shorter life expectancy than the average population. Physical activity can treat and prevent several diseases, e.g. cardiovascular and metabolic disorders as well as psychiatric symptoms. It is therefore of utmost importance to develop effective methods to integrate physical activity into psychiatric care. To meet this need, the physical activity intervention Braining was developed. This study aims to describe Braining, to assess the number of patients reached during the first years of pilot testing, to analyze clinical data in the group of patients participating in Braining 2017-2020 and to assess the intervention.

METHODS

In this descriptive retrospective study we analyzed data from all patients participating in Braining training sessions ≥ 3 times (n = 239), the Braining Participants. Regular patients at the clinic served as a comparison. Furthermore, medical records were studied for a smaller cohort (n = 51), the Braining Pilot Cohort. Data was analyzed using Chi-square and Fisher's tests.

RESULTS

During the introduction period of Braining, 580 patients attended an information meeting about Braining, or at least one training session. 239 patients participated in ≥ 3 training sessions, considered to be participants of Braining. These Braining Participants (n = 239), ages 19 to 82, males 23.4%, attended between 3 and 308 training sessions (median 9). The main diagnoses were affective and anxiety disorders. Number of diagnoses ranged from 0 to 10 (median = 2). For the subsample, the Braining Pilot Cohort (n = 51), participants attended between 3 and 208 training sessions (median = 20). Twelve percent were working full-time, and symptom severity of depression and general anxiety was moderate. Two thirds had ≥ 3 different classes of medication. Regarding metabolic morbidity, 28 had been diagnosed with hypertension, though blood lipids, blood glucose as well as blood pressure were within the normal range. Thirty-seven percent were prescribed Physical Activity on Prescription during 2017-2020. One severe adverse event was reported.

CONCLUSIONS

The Braining intervention reached all age-groups and patients with a wide and representative diagnostic panorama, suggesting that Braining could be a promising and safe method for implementing physical activity in a psychiatric patient population.

Transcription factor GATA6 promotes migration of human coronary artery smooth muscle cells in vitro

Vascular smooth muscle cell plasticity plays a pivotal role in the pathophysiology of vascular diseases. Despite compelling evidence demonstrating the importance of transcription factor GATA6 in vascular smooth muscle, the functional role of GATA6 remains poorly understood. The aim of this study was to elucidate the role of GATA6 on cell migration and to gain insight into GATA6-sensitive genes in smooth muscle. We found that overexpression of GATA6 promotes migration of human coronary artery smooth muscle cells in vitro, and that silencing of GATA6 in smooth muscle cells resulted in reduced cellular motility. Furthermore, a complete microarray screen of GATA6-sensitive gene transcription resulted in 739 upregulated and 248 downregulated genes. Pathways enrichment analysis showed involvement of transforming growth factor beta (TGF-β) signaling which was validated by measuring mRNA expression level of several members. Furthermore, master regulators prediction based on microarray data revealed several members of (mitogen activated protein kinase) MAPK pathway as a master regulators, reflecting involvement of MAPK pathway also. Our findings provide further insights into the functional role of GATA6 in vascular smooth muscle and suggest that targeting GATA6 may constitute as a new approach to inhibit vascular smooth muscle migration.

STEM-19. LIVE DETECTION OF NEURAL STEM AND GLIOBLASTOMA CELLS BY A LUMINESCENT CONJUGATED OLIGOTHIOPHENE DERIVATIVE

Glioblastoma (GBM) is an aggressive nervous system tumor with a mean survival time of 12-14 months. Cells with neural stem cell-like properties can be derived from GBM tumors. These cells seem to escape conventional irradiation treatment, chemotherapy, and surgery, and may play a crucial role for relapse. It is therefore urgent to develop novel approaches for reliable detection of neural stem cell-like cells in GBM. Here we report a luminescent conjugated oligothiophene (LCO), named GlioStem (p-HTMI), for non-invasive and non-amplified real-time detection of live human patient-derived GBM cells and embryonic neural stem/progenitor cells (NSPCs). Within a maximum of 10 minutes after administration of the molecule in vitro, in the existing media, fluorescence emission was observed without any modulation of the cells or additional vehicle, resulting in efficient detection of cytoplasmic luminescent signal in NSPCs or GBM cells from rodents and humans, detectable at Alexa488/GFP wavelength. GlioStem is functionalized with a methylated imidazole moiety resembling the side chain of histidine/histamine, and non-methylated analogues were not functional. In vitro, GlioStem was shown to identify fetal cortical NSPCs from rat (FGF2-expanded), embryonic stem cell-derived NSPCs from mouse (FGF2/EGF-expanded), and FGF2-exposed C6 glioma cell cultures from rat, but not any other cell types investigated. Cell sorting experiments of patient-derived, FGF2/EGF-expanded GBM cells demonstrated that GlioStem in addition to NSPC-markers like Nestin and Sox2 labeled the same population (overlap > 90%) of cells as CD271, a proposed marker for stem cell-like cells and rapidly migrating cells in glioblastoma. Our results suggest that the LCO GlioStem is a versatile tool for immediate and selective detection of subpopulations of neural stem and glioma cells.

PRC2-mediated repression is essential to maintain identity and function of differentiated dopaminergic and serotonergic neurons

How neurons can maintain cellular identity over an entire life span remains largely unknown. Here, we show that maintenance of identity in differentiated dopaminergic and serotonergic neurons is critically reliant on the Polycomb repressive complex 2 (PRC2). Deletion of the obligate PRC2 component, Eed, in these neurons resulted in global loss of H3K27me3, followed by a gradual activation of genes harboring both H3K27me3 and H3K9me3 modifications. Notably, H3K9me3 was lost at these PRC2 targets before gene activation. Neuronal survival was not compromised; instead, there was a reduction in subtype-specific gene expression and a progressive impairment of dopaminergic and serotonergic neuronal function, leading to behavioral deficits characteristic of Parkinson's disease and anxiety. Single-cell analysis revealed subtype-specific vulnerability to loss of PRC2 repression in dopamine neurons of the substantia nigra. Our study reveals that a PRC2-dependent nonpermissive chromatin state is essential to maintain the subtype identity and function of dopaminergic and serotonergic neurons.

Impaired oxygen-sensitive regulation of mitochondrial biogenesis within the von Hippel-Lindau syndrome

Mitochondria are the main consumers of oxygen within the cell. How mitochondria sense oxygen levels remains unknown. Here we show an oxygen-sensitive regulation of TFAM, an activator of mitochondrial transcription and replication, whose alteration is linked to tumours arising in the von Hippel-Lindau syndrome. TFAM is hydroxylated by EGLN3 and subsequently bound by the von Hippel-Lindau tumour-suppressor protein, which stabilizes TFAM by preventing mitochondrial proteolysis. Cells lacking wild-type VHL or in which EGLN3 is inactivated have reduced mitochondrial mass. Tumorigenic VHL variants leading to different clinical manifestations fail to bind hydroxylated TFAM. In contrast, cells harbouring the Chuvash polycythaemia VHL^R200W mutation, involved in hypoxia-sensing disorders without tumour development, are capable of binding hydroxylated TFAM. Accordingly, VHL-related tumours, such as pheochromocytoma and renal cell carcinoma cells, display low mitochondrial content, suggesting that impaired mitochondrial biogenesis is linked to VHL tumorigenesis. Finally, inhibiting proteolysis by targeting LONP1 increases mitochondrial content in VHL-deficient cells and sensitizes therapy-resistant tumours to sorafenib treatment. Our results offer pharmacological avenues to sensitize therapy-resistant VHL tumours by focusing on the mitochondria.

YAP and TAZ in Vascular Smooth Muscle Confer Protection Against Hypertensive Vasculopathy

BACKGROUND

Hypertension remains a major risk factor for cardiovascular diseases, but the underlying mechanisms are not well understood. We hypothesize that appropriate mechanotransduction and contractile function in vascular smooth muscle cells are crucial to maintain vascular wall integrity. The Hippo pathway effectors YAP (yes-associated protein 1) and TAZ (WW domain containing transcription regulator 1) have been identified as mechanosensitive transcriptional coactivators. However, their role in vascular smooth muscle cell mechanotransduction has not been investigated in vivo.

METHODS

We performed physiological and molecular analyses utilizing an inducible smooth muscle-specific YAP/TAZ knockout mouse model.

RESULTS

Arteries lacking YAP/TAZ have reduced agonist-mediated contraction, decreased myogenic response, and attenuated stretch-induced transcriptional regulation of smooth muscle markers. Moreover, in established hypertension, YAP/TAZ knockout results in severe vascular lesions in small mesenteric arteries characterized by neointimal hyperplasia, elastin degradation, and adventitial thickening.

CONCLUSIONS

This study demonstrates a protective role of YAP/TAZ against hypertensive vasculopathy.

Effect of DMSO on the catalytical production of 2,5-bis(hydoxymethyl)furan from 5-hydroxymethylfurfural over Ni/SiO2 catalysts

Highly effective production of 2,5-bis(hydoxymethyl)furan (BHMF) from 5-hydroxymethylfurfural (HMF) has been achieved over Ni/SiO2 catalyst. An effect of DMSO on the HMF hydrogenation is demonstrated under practical conditions.

Curriculum for vestibular medicine (vestmed) proposed by the barany society

This document presents the initiative of the Bárány Society to improve diagnosis and care of patients presenting with vestibular symptoms worldwide.

The Vestibular Medicine (VestMed) concept embraces a wide approach to the potential causes of vestibular symptoms, acknowledging that vertigo, dizziness, and unsteadiness are non-specific symptoms that may arise from a broad spectrum of disorders, spanning from the inner ear to the brainstem, cerebellum and supratentorial cerebral networks, to many disorders beyond these structures.

The Bárány Society Vestibular Medicine Curriculum (BS-VestMed-Cur) is based on the concept that VestMed is practiced by different physician specialties and non-physician allied health professionals. Each profession has its characteristic disciplinary role and profile, but all work in overlapping areas. Each discipline requires good awareness of the variety of disorders that can present with vestibular symptoms, their underlying mechanisms and etiologies, diagnostic criteria and treatment options. Similarly, all disciplines require an understanding of their own limitations, the contribution to patient care from other professionals and when to involve other members of the VestMed community. Therefore, the BS-VestMed-Cur is the same for all health professionals involved, the overlaps and differences of the various relevant professions being defined by different levels of detail and depth of knowledge and skills.

The BS-VestMed-Cur defines a Basic and an Expert Level Curriculum. The Basic Level Curriculum covers the VestMed topics in less detail and depth, yet still conveys the concept of the wide net approach. It is designed for health professionals as an introduction to, and first step toward, VestMed expertise. The Expert Level Curriculum defines a Focused and Broad Expert. It covers the VestMed spectrum in high detail and requires a high level of understanding. In the Basic and Expert Level Curricula, the range of topics is the same and runs from anatomy, physiology and physics of the vestibular system, to vestibular symptoms, history taking, bedside examination, ancillary testing, the various vestibular disorders, their treatment and professional attitudes. Additionally, research topics relevant to clinical practice are included in the Expert Level Curriculum. For Focused Expert proficiency, the Basic Level Curriculum is required to ensure a broad overview and additionally requires an expansion of knowledge and skills in one or a few specific topics related to the focused expertise, e.g. inner ear surgery. Broad Expert proficiency targets professionals who deal with all sorts of patients presenting with vestibular symptoms (e.g. otorhinolaryngologists, neurologists, audiovestibular physicians, physical therapists), requiring a high level of VestMed expertise across the whole spectrum. For the Broad Expert, the Expert Level Curriculum is required in which the minimum attainment targets for all the topics go beyond the Basic Level Curriculum. The minimum requirements regarding knowledge and skills vary between Broad Experts, since they are tuned to the activity profile and underlying specialty of the expert.

  The BS-VestMed-Cur aims to provide a basis for current and future teaching and training programs for physicians and non-physicians. The Basic Level Curriculum could also serve as a resource for inspiration for teaching VestMed to students, postgraduate generalists such as primary care physicians and undergraduate health professionals, or anybody wishing to enter VestMed.

  VestMed is considered a set of competences related to an area of practice of established physician specialties and non-physician health professions rather than a separate clinical specialty. This curriculum does not aim to define a new single clinical specialty.

  The BS-VestMed-Cur should also integrate with, facilitate and encourage translational research in the vestibular field.

Single-nuclei transcriptomes from human adrenal gland reveal distinct cellular identities of low and high-risk neuroblastoma tumors

Childhood neuroblastoma has a remarkable variability in outcome. Age at diagnosis is one of the most important prognostic factors, with children less than 1 year old having favorable outcomes. Here we study single-cell and single-nuclei transcriptomes of neuroblastoma with different clinical risk groups and stages, including healthy adrenal gland. We compare tumor cell populations with embryonic mouse sympatho-adrenal derivatives, and post-natal human adrenal gland. We provide evidence that low and high-risk neuroblastoma have different cell identities, representing two disease entities. Low-risk neuroblastoma presents a transcriptome that resembles sympatho- and chromaffin cells, whereas malignant cells enriched in high-risk neuroblastoma resembles a subtype of TRKB+ cholinergic progenitor population identified in human post-natal gland. Analyses of these populations reveal different gene expression programs for worst and better survival in correlation with age at diagnosis. Our findings reveal two cellular identities and a composition of human neuroblastoma tumors reflecting clinical heterogeneity and outcome.

Dizziness and localized pain are often concurrent in patients with balance or psychological disorders

Background and aims Symptoms of dizziness and pain are both common complaints and the two symptoms often seem to coincide. When symptoms appear concomitant for sustained periods of time the symptoms might maintain and even exacerbate each other, sometimes leading to psychological distress. In order to evaluate such comorbidity we studied patients referred to a vestibular unit and to a psychiatric outpatient clinic with respectively balance disorders and psychological issues. Methods Consecutive patients referred to a vestibular unit (n = 49) and a psychiatric outpatient clinic (n = 62) answered the Dizziness Handicap Inventory (DHI) questionnaire and a questionnaire detailing occurrence of dizziness and pain. Results The experience of dizziness and pain often coincided within individuals across both clinical populations, especially if the pain was located to the neck/shoulder or the back (p = 0.006). Patients who reported dizziness had significantly more often pain (p = 0.024); in the head (p = 0.002), neck/shoulders (p = 0.003) and feet (p = 0.043). Moreover, patients who reported dizziness stated significantly higher scoring on emotional (p < 0.001) and functional (p < 0.001) DHI sub-scales. Furthermore, patients who reported an accident in their history suffered significantly more often from dizziness (p = 0.039) and pain (p < 0.001); in the head (p < 0.001), neck/shoulders (p < 0.001) and arms (p = 0.045) and they scored higher on the emotional (p = 0.004) and functional (p = 0.002) DHI sub-scales. Conclusions The findings suggest comorbidity to exist between dizziness and neck/shoulder or back pain in patients seeking health care for balance disorders or psychological issues. Patients suffering from dizziness and pain, or with both symptoms, also reported higher emotional and functional strain. Thus, healthcare professionals should consider comorbidity when determining diagnosis and consequent measures. Implications Clinicians need to have a broader "receptive scope" in both history and clinical examinations, and ask for all symptoms. Although the patients in this study visited a vestibular unit respectively a psychological clinic, they commonly reported pain conditions when explicitly asked for this symptom. A multimodal approach is thus to favor, especially when the symptoms persist, for the best clinical management.

Aberrant splicing in neuroblastoma generates RNA-fusion transcripts and provides vulnerability to spliceosome inhibitors

The paucity of recurrent mutations has hampered efforts to understand and treat neuroblastoma. Alternative splicing and splicing-dependent RNA-fusions represent mechanisms able to increase the gene product repertoire but their role in neuroblastoma remains largely unexplored. Here we investigate the presence and possible roles of aberrant splicing and splicing-dependent RNA-fusion transcripts in neuroblastoma. In addition, we attend to establish whether the spliceosome can be targeted to treat neuroblastoma. Through analysis of RNA-sequenced neuroblastoma we show that elevated expression of splicing factors is a strong predictor of poor clinical outcome. Furthermore, we identified >900 primarily intrachromosomal fusions containing canonical splicing sites. Fusions included transcripts from well-known oncogenes, were enriched for proximal genes and in chromosomal regions commonly gained or lost in neuroblastoma. As a proof-of-principle that these fusions can generate altered gene products, we characterized a ZNF451-BAG2 fusion, producing a truncated BAG2-protein which inhibited retinoic acid induced differentiation. Spliceosome inhibition impeded neuroblastoma fusion expression, induced apoptosis and inhibited xenograft tumor growth. Our findings elucidate a splicing-dependent mechanism generating altered gene products in neuroblastoma and show that the spliceosome is a potential target for clinical intervention.

Activation of endogenous retroviruses during brain development causes an inflammatory response

Endogenous retroviruses (ERVs) make up a large fraction of mammalian genomes and are thought to contribute to human disease, including brain disorders. In the brain, aberrant activation of ERVs is a potential trigger for an inflammatory response, but mechanistic insight into this phenomenon remains lacking. Using CRISPR/Cas9‐based gene disruption of the epigenetic co‐repressor protein Trim28, we found a dynamic H3K9me3‐dependent regulation of ERVs in proliferating neural progenitor cells (NPCs), but not in adult neurons. In vivo deletion of Trim28 in cortical NPCs during mouse brain development resulted in viable offspring expressing high levels of ERVs in excitatory neurons in the adult brain. Neuronal ERV expression was linked to activated microglia and the presence of ERV‐derived proteins in aggregate‐like structures. This study demonstrates that brain development is a critical period for the silencing of ERVs and provides causal in vivo evidence demonstrating that transcriptional activation of ERV in neurons results in an inflammatory response.

MRTFA overexpression promotes conversion of human coronary artery smooth muscle cells into lipid-laden foam cells

OBJECTIVE

Smooth muscle cells contribute significantly to lipid-laden foam cells in atherosclerotic plaques. However, the underlying mechanisms transforming smooth muscle cells into foam cells are poorly understood. The purpose of this study was to gain insight into the molecular mechanisms regulating smooth muscle foam cell formation.

APPROACH AND RESULTS

Using human coronary artery smooth muscle cells we found that the transcriptional co-activator MRTFA promotes lipid accumulation via several mechanisms, including direct transcriptional control of LDL receptor, enhanced fluid-phase pinocytosis and reduced lipid efflux. Inhibition of MRTF activity with CCG1423 and CCG203971 significantly reduced lipid accumulation. Furthermore, we demonstrate enhanced MRTFA expression in vascular remodeling of human vessels.

CONCLUSIONS

This study demonstrates a novel role for MRTFA as an important regulator of lipid homeostasis in vascular smooth muscle cells. Thus, MRTFA could potentially be a new therapeutic target for inhibition of vascular lipid accumulation.

The Rapid Implementation of a Psychological Support Model for Frontline Healthcare Workers During the COVID-19 Pandemic: A Case Study and Process Evaluation

The COVID-19 pandemic highlighted the need for psychological support initiatives directed toward frontline healthcare workers, which can be rapidly and sustainably implemented during an infectious disease outbreak. The current case study presents a comprehensive model of psychological support that was implemented at an intensive care unit (ICU) during the first wave of the COVID-19 pandemic. The psychological support model aimed at promoting a resilient stress reaction among frontline staff by protecting physical, social, and psychological resources. The initiatives, targeting different groups of workers, included education and training, peer support, psychologist-supervised and unsupervised group sessions, on-boarding for transferred staff, manager support, and individual sessions for workers experiencing strong stress reactions. The results of the process evaluation of this rapid implementation suggest that peer support initiatives as well as daily group sessions were the most appreciated forms of psychological support. Psychologists involved in organizing and providing the support highlighted several aspects of a successful implementation of the support model: offering support during work hours (preferably after shift), positive attitude of line managers that framed support initiatives as a team effort, and involvement of experienced psychologists able to quickly adjust the content of the support according to the current needs. The study also identified two main problems of the current implementation: the lack of efficient planning due to the use of volunteer work and the need for more structural resources on the organizational level to ensure long-term sustainability of the support model and its implementation among all groups of healthcare staff. The current case study highlights the importance of establishing permanent structural resources and routines for psychological support integrated in clinical practice by healthcare organizations to improve both rapid and sustainable response to future crises.

Psychological Flexibility and Its Relationship to Distress and Work Engagement Among Intensive Care Medical Staff

Intensive care settings place specific work-related demands on health care professionals that may elicit stress and negatively influence occupational health and work engagement. Psychological flexibility has emerged as a promising construct that could help explain variation in reported health. Understanding the role of psychological flexibility in occupational psychological health among intensive care medical staff may potentially guide the development of effective interventions. Thus, the present study evaluated the relationships between psychological flexibility (Work-related Acceptance and Action Questionnaire), distress (Perceived Stress Scale, General Health Questionnaire) and work engagement (Utrecht Work Engagement Scale) in a sample of 144 health care professionals from one adult (ICU, N = 98) and one pediatric (PICU, N = 46) intensive care unit. In addition to cross-sectional analyses, a subset of data (PICU, N = 46) was analyzed using a longitudinal design. Results illustrated that higher levels of distress were associated with lower levels of work engagement. Furthermore, psychological flexibility was related to greater work engagement, and psychological flexibility had a significant indirect effect on the relationship between distress and work engagement. Lastly, increased psychological flexibility over time corresponded with increased work engagement. Although tentative, the results suggest the importance of psychological flexibility for work engagement in health care professionals within intensive care settings.

Inducible Deletion of YAP and TAZ in Adult Mouse Smooth Muscle Causes Rapid and Lethal Colonic Pseudo-Obstruction

BACKGROUND & AIMS

YAP (Yap1) and TAZ (Wwtr1) are transcriptional co-activators and downstream effectors of the Hippo pathway, which play crucial roles in organ size control and cancer pathogenesis. Genetic deletion of YAP/TAZ has shown their critical importance for embryonic development of the heart, vasculature, and gastrointestinal mesenchyme. The aim of this study was to determine the functional role of YAP/TAZ in adult smooth muscle cells in vivo.

METHODS

Because YAP and TAZ are mutually redundant, we used YAP/TAZ double-floxed mice crossed with mice that express tamoxifen-inducible CreER^T2 recombinase driven by the smooth muscle-specific myosin heavy chain promoter.

RESULTS

Double-knockout of YAP/TAZ in adult smooth muscle causes lethality within 2 weeks, mainly owing to colonic pseudo-obstruction, characterized by severe distension and fecal impaction. RNA sequencing in colon and urinary bladder showed that smooth muscle markers and muscarinic receptors were down-regulated in the YAP/TAZ knockout. The same transcripts also correlated with YAP/TAZ in the human colon. Myograph experiments showed reduced contractility to depolarization by potassium chloride and a nearly abolished muscarinic contraction and spontaneous activity in colon rings of YAP/TAZ knockout.

CONCLUSIONS

YAP and TAZ in smooth muscle are guardians of colonic contractility and control expression of contractile proteins and muscarinic receptors. The knockout model has features of human chronic intestinal pseudo-obstruction and may be useful for studying this disease.

Identification of the intermediate filament protein synemin/SYNM as a target of myocardin family coactivators

Myocardin (MYOCD) is a critical regulator of smooth muscle cell (SMC) differentiation, but its transcriptional targets remain to be exhaustively characterized, especially at the protein level. Here we leveraged human RNA and protein expression data to identify novel potential MYOCD targets. Using correlation analyses we found several targets that we could confirm at the protein level, including SORBS1, SLMAP, SYNM, and MCAM. We focused on SYNM, which encodes the intermediate filament protein synemin. SYNM rivalled smooth muscle myosin (MYH11) for SMC specificity and was controlled at the mRNA and protein levels by all myocardin-related transcription factors (MRTFs: MYOCD, MRTF-A/MKL1, and MRTF-B/MKL2). MRTF activity is regulated by the ratio of filamentous to globular actin, and SYNM was accordingly reduced by interventions that depolymerize actin, such as latrunculin treatment and overexpression of constitutively active cofilin. Many MRTF target genes depend on serum response factor (SRF), but SYNM lacked SRF-binding motifs in its proximal promoter, which was not directly regulated by MYOCD. Furthermore, SYNM resisted SRF silencing, yet the time course of induction closely paralleled that of the SRF-dependent target gene ACTA2. SYNM was repressed by the ternary complex factor (TCF) FLI1 and was increased in mouse embryonic fibroblasts lacking three classical TCFs (ELK1, ELK3, and ELK4). Imaging showed colocalization of SYNM with the intermediate filament proteins desmin and vimentin, and MRTF-A/MKL1 increased SYNM-containing intermediate filaments in SMCs. These studies identify SYNM as a novel SRF-independent target of myocardin that is abundantly expressed in all SMCs.

EPAS1/HIF2α correlates with features of low-risk neuroblastoma and with adrenal chromaffin cell differentiation during sympathoadrenal development

The hypoxia inducible transcription factor EPAS1/HIF2α has been described as an oncogene and a potential therapeutic target in neuroblastoma. Our analysis of several neuroblastoma tumour expression datasets does not support an oncogenic role, instead EPAS1 expression is associated with better patient outcome and characteristics of low-risk tumours. Treatment with HIF2α inhibitors did not block in vitro neuroblastoma cell proliferation nor xenograft growth. In addition, we analysed single cell sequencing data sets from the developing mouse sympathoadrenal lineage, wherein expression of Epas1 was a strong predictor of differentiated adrenal chromaffin cells and negatively correlated with progenitor characteristics. This was reflected in neuroblastoma tumours wherein genes co-expressed with Epas1 during sympathoadrenal development strongly predicts favourable patient outcome and features of low-risk tumours. Thus, our analysis suggest that with the current available data EPAS1/HIF2α should not be classified as a neuroblastoma oncogene and is less likely to represent a suitable drug target in this disease.

Author Correction: A comprehensive map coupling histone modifications with gene regulation in adult dopaminergic and serotonergic neurons

In the originally published version of this Article, financial support was not fully acknowledged. The PDF and HTML versions of the Article have now been corrected to include support to Thomas Perlmann provided by Knut and Alice Wallenberg Foundation (grant 2013.0075) and Swedish Research Council (VR; grant 2016-02506).

Nexilin/NEXN controls actin polymerization in smooth muscle and is regulated by myocardin family coactivators and YAP

Nexilin, encoded by the NEXN gene, is expressed in striated muscle and localizes to Z-discs, influencing mechanical stability. We examined Nexilin/NEXN in smooth muscle cells (SMCs), and addressed if Nexilin localizes to dense bodies and dense bands and whether it is regulated by actin-controlled coactivators from the MRTF (MYOCD, MKL1, MKL2) and YAP/TAZ (YAP1 and WWTR1) families. NEXN expression in SMCs was comparable to that in striated muscles. Immunofluorescence and immunoelectron microscopy suggested that Nexilin localizes to dense bodies and dense bands. Correlations at the mRNA level suggested that NEXN expression might be controlled by actin polymerization. Depolymerization of actin using Latrunculin B repressed the NEXN mRNA and protein in bladder and coronary artery SMCs. Overexpression and knockdown supported involvement of both YAP/TAZ and MRTFs in the transcriptional control of NEXN. YAP/TAZ and MRTFs appeared equally important in bladder SMCs, whereas MRTFs dominated in vascular SMCs. Expression of NEXN was moreover reduced in situations of SMC phenotypic modulation in vivo. The proximal promoter of NEXN conferred control by MRTF-A/MKL1 and MYOCD. NEXN silencing reduced actin polymerization and cell migration, as well as SMC marker expression. NEXN targeting by actin-controlled coactivators thus amplifies SMC differentiation through the actin cytoskeleton, probably via dense bodies and dense bands.

Reprint of: A chemical screen identifies trifluoperazine as an inhibitor of glioblastoma growth

Glioblastoma (GBM) is regarded as the most common malignant brain tumor but treatment options are limited. Thus, there is an unmet clinical need for compounds and corresponding targets that could inhibit GBM growth. We screened a library of 80 dopaminergic ligands with the aim of identifying compounds capable of inhibiting GBM cell line proliferation and survival. Out of 45 active compounds, 8 were further validated. We found that the dopamine receptor D2 antagonist trifluoperazine 2HCl inhibits growth and proliferation of GBM cells in a dose dependent manner. Trifluoperazine's inhibition of GBM cells is cell line dependent and correlates with variations in dopamine receptor expression profile. We conclude that components of the dopamine receptor signaling pathways are potential targets for pharmacological interventions of GBM growth.

Loss of Vascular Myogenic Tone in miR-143/145 Knockout Mice Is Associated With Hypertension-Induced Vascular Lesions in Small Mesenteric Arteries

OBJECTIVE

Pressure-induced myogenic tone is involved in autoregulation of local blood flow and confers protection against excessive pressure levels in small arteries and capillaries. Myogenic tone is dependent on smooth muscle microRNAs (miRNAs), but the identity of these miRNAs is unclear. Furthermore, the consequences of altered myogenic tone for hypertension-induced damage to small arteries are not well understood.

APPROACH AND RESULTS

The importance of smooth muscle-enriched microRNAs, miR-143/145, for myogenic tone was evaluated in miR-143/145 knockout mice. Furthermore, hypertension-induced vascular injury was evaluated in mesenteric arteries in vivo after angiotensin II infusion. Myogenic tone was abolished in miR-143/145 knockout mesenteric arteries, whereas contraction in response to calyculin A and potassium chloride was reduced by ≈30%. Furthermore, myogenic responsiveness was potentiated by angiotensin II in wild-type but not in knockout mice. Angiotensin II administration in vivo elevated systemic blood pressure in both genotypes. Hypertensive knockout mice developed severe vascular lesions characterized by vascular inflammation, adventitial fibrosis, and neointimal hyperplasia in small mesenteric arteries. This was associated with depolymerization of actin filaments and fragmentation of the elastic laminae at the sites of vascular lesions.

CONCLUSIONS

This study demonstrates that miR-143/145 expression is essential for myogenic responsiveness. During hypertension, loss of myogenic tone results in potentially damaging levels of mechanical stress and detrimental effects on small arteries. The results presented herein provide novel insights into the pathogenesis of vascular disease and emphasize the importance of controlling mechanical factors to maintain structural integrity of the vascular wall.

Sumoylation of Notch1 represses its target gene expression during cell stress

The Notch signaling pathway is a key regulator of stem cells during development, and its deregulated activity is linked to developmental defects and cancer. Transcriptional activation of Notch target genes requires cleavage of the Notch receptor in response to ligand binding, production of the Notch intracellular domain (NICD1), NICD1 migration into the nucleus, and assembly of a transcriptional complex. Post-translational modifications of Notch regulate its trafficking, turnover, and transcriptional activity. Here, we show that NICD1 is modified by small ubiquitin-like modifier (SUMO) in a stress-inducible manner. Sumoylation occurs in the nucleus where NICD1 is sumoylated in the RBPJ-associated molecule (RAM) domain. Although stress and sumoylation enhance nuclear localization of NICD1, its transcriptional activity is attenuated. Molecular modeling indicates that sumoylation can occur within the DNA-bound ternary transcriptional complex, consisting of NICD1, the transcription factor Suppressor of Hairless (CSL), and the co-activator Mastermind-like (MAML) without its disruption. Mechanistically, sumoylation of NICD1 facilitates the recruitment of histone deacetylase 4 (HDAC4) to the Notch transcriptional complex to suppress Notch target gene expression. Stress-induced sumoylation decreases the NICD1-mediated induction of Notch target genes, which was abrogated by expressing a sumoylation-defected mutant in cells and in the developing central nervous system of the chick in vivo. Our findings of the stress-inducible sumoylation of NICD1 reveal a novel context-dependent regulatory mechanism of Notch target gene expression.

A chemical screen identifies trifluoperazine as an inhibitor of glioblastoma growth

Glioblastoma (GBM) is regarded as the most common malignant brain tumor but treatment options are limited. Thus, there is an unmet clinical need for compounds and corresponding targets that could inhibit GBM growth. We screened a library of 80 dopaminergic ligands with the aim of identifying compounds capable of inhibiting GBM cell line proliferation and survival. Out of 45 active compounds, 8 were further validated. We found that the dopamine receptor D2 antagonist trifluoperazine 2HCl inhibits growth and proliferation of GBM cells in a dose dependent manner. Trifluoperazine's inhibition of GBM cells is cell line dependent and correlates with variations in dopamine receptor expression profile. We conclude that components of the dopamine receptor signaling pathways are potential targets for pharmacological interventions of GBM growth.

Molecular Regulation of Arterial Aneurysms: Role of Actin Dynamics and microRNAs in Vascular Smooth Muscle

Aortic aneurysms are defined as an irreversible increase in arterial diameter by more than 50% relative to the normal vessel diameter. The incidence of aneurysm rupture is about 10 in 100,000 persons per year and ruptured arterial aneurysms inevitably results in serious complications, which are fatal in about 40% of cases. There is also a hereditary component of the disease and dilation of the ascending thoracic aorta is often associated with congenital heart disease such as bicuspid aortic valves (BAV). Furthermore, specific mutations that have been linked to aneurysm affect polymerization of actin filaments. Polymerization of actin is important to maintain a contractile phenotype of smooth muscle cells enabling these cells to resist mechanical stress on the vascular wall caused by the blood pressure according to the law of Laplace. Interestingly, polymerization of actin also promotes smooth muscle specific gene expression via the transcriptional co-activator MRTF, which is translocated to the nucleus when released from monomeric actin. In addition to genes encoding for proteins involved in the contractile machinery, recent studies have revealed that several non-coding microRNAs (miRNAs) are regulated by this mechanism. The importance of these miRNAs for aneurysm development is only beginning to be understood. This review will summarize our current understanding about the influence of smooth muscle miRNAs and actin polymerization for the development of arterial aneurysms.

Absence of microRNA-21 does not reduce muscular dystrophy in mouse models of LAMA2-CMD

MicroRNAs (miRNAs) are short non-coding RNAs that modulate gene expression post-transcriptionally. Current evidence suggests that miR-21 plays a significant role in the progression of fibrosis in muscle diseases. Laminin-deficient congenital muscular dystrophy (LAMA2-CMD) is a severe form of congenital muscular dystrophy caused by mutations in the gene encoding laminin α2 chain. Mouse models dy^3K/dy^3K and dy^2J/dy^2J, respectively, adequately mirror severe and milder forms of LAMA2-CMD. Both human and mouse LAMA2-CMD muscles are characterized by extensive fibrosis and considering that fibrosis is the final step that destroys muscle during the disease course, anti-fibrotic therapies may be effective strategies for prevention of LAMA2-CMD. We have previously demonstrated a significant up-regulation of the pro-fibrotic miR-21 in dy^3K/dy^3K and dy^2J/dy^2J skeletal muscle. Hence, the objective of this study was to explore if absence of miR-21 reduces fibrogenesis and improves the phenotype of LAMA2-CMD mice. Thus, we generated dy^3K/dy^3K and dy^2J/dy^2J mice devoid of miR-21 (dy^3K/miR-21 and dy^2J/miR-21 mice, respectively). However, the muscular dystrophy phenotype of dy^3K/miR-21 and dy^2J/miR-21 double knock-out mice was not improved compared to dy^3K/dy^3K or dy^2J/dy^2J mice, respectively. Mice displayed the same body weight, dystrophic muscles (with fibrosis) and impaired muscle function. These data indicate that miR-21 may not be involved in the development of fibrosis in LAMA2-CMD.

SOX5/6/21 Prevent Oncogene-Driven Transformation of Brain Stem Cells

Molecular mechanisms preventing self-renewing brain stem cells from oncogenic transformation are poorly defined. We show that the expression levels of SOX5, SOX6, and SOX21 (SOX5/6/21) transcription factors increase in stem cells of the subventricular zone (SVZ) upon oncogenic stress, whereas their expression in human glioma decreases during malignant progression. Elevated levels of SOX5/6/21 promoted SVZ cells to exit the cell cycle, whereas genetic ablation of SOX5/6/21 dramatically increased the capacity of these cells to form glioma-like tumors in an oncogene-driven mouse brain tumor model. Loss-of-function experiments revealed that SOX5/6/21 prevent detrimental hyperproliferation of oncogene expressing SVZ cells by facilitating an antiproliferative expression profile. Consistently, restoring high levels of SOX5/6/21 in human primary glioblastoma cells enabled expression of CDK inhibitors and decreased p53 protein turnover, which blocked their tumorigenic capacity through cellular senescence and apoptosis. Altogether, these results provide evidence that SOX5/6/21 play a central role in driving a tumor suppressor response in brain stem cells upon oncogenic insult. Cancer Res; 77(18); 4985-97. ©2017 AACR.

Glioma-induced inhibition of caspase-3 in microglia promotes a tumor-supportive phenotype

Glioma cells recruit and exploit microglia (the resident immune cells of the brain) for their proliferation and invasion ability. The underlying molecular mechanism used by glioma cells to transform microglia into a tumor-supporting phenotype has remained elusive. We found that glioma-induced microglia conversion was coupled to a reduction in the basal activity of microglial caspase-3 and increased S-nitrosylation of mitochondria-associated caspase-3 through inhibition of thioredoxin-2 activity, and that inhibition of caspase-3 regulated microglial tumor-supporting function. Furthermore, we identified the activity of nitric oxide synthase 2 (NOS2, also known as iNOS) originating from the glioma cells as a driving stimulus in the control of microglial caspase-3 activity. Repression of glioma NOS2 expression in vivo led to a reduction in both microglia recruitment and tumor expansion, whereas depletion of microglial caspase-3 gene promoted tumor growth. Our results provide evidence that inhibition of the denitrosylation of S-nitrosylated procaspase-3 mediated by the redox protein Trx2 is a part of the microglial pro-tumoral activation pathway initiated by glioma cancer cells.

Elevated levels of ZAC1 disrupt neurogenesis and promote rapid in vivo reprogramming

The zinc finger transcription factor Zac1 is expressed in dividing progenitors of the nervous system with expression levels negatively controlled by genomic imprinting. To explore the consequences of elevated ZAC1 levels during neurogenesis we overexpressed it in the developing CNS. Increased levels of ZAC1 rapidly promoted upregulation of CDK inhibitors P57 and P27 followed by cell cycle exit. Surprisingly this was accompanied by stalled neuronal differentiation. Genome wide expression analysis of cortical cells overexpressing Zac1 revealed a decrease in neuronal gene expression and an increased expression of imprinted genes, factors regulating mesoderm formation as well as features of differentiated muscle. In addition, we observed a rapid induction of several genes regulating pluripotency. Taken together, our data suggests that expression levels of Zac1 need to be kept under strict control to avoid premature cell cycle exit, disrupted neurogenesis and aberrant expression of non-neuronal genes including pluripotency associated factors.

Sarcospan integration into laminin-binding adhesion complexes that ameliorate muscular dystrophy requires utrophin and α7 integrin

Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene that result in loss of the dystrophin-glycoprotein complex, a laminin receptor that connects the myofiber to its surrounding extracellular matrix. Utrophin, a dystrophin ortholog that is normally localized to the neuromuscular junction, is naturally upregulated in DMD muscle, which partially compensates for the loss of dystrophin. Transgenic overexpression of utrophin causes broad sarcolemma localization of utrophin, restoration of laminin binding and amelioration of disease in the mdx mouse model of DMD. We previously demonstrated that overexpression of sarcospan, a dystrophin- and utrophin-binding protein, ameliorates mdx muscular dystrophy. Sarcospan boosts levels of utrophin to therapeutic levels at the sarcolemma, where attachment to laminin is restored. However, understanding the compensatory mechanism is complicated by concomitant upregulation of α7β1 integrin, which also binds laminin. Similar to the effects of utrophin, transgenic overexpression of α7 integrin prevents DMD disease in mice and is accompanied by increased abundance of utrophin around the extra-synaptic sarcolemma. In order to investigate the mechanisms underlying sarcospan 'rescue' of muscular dystrophy, we created double-knockout mice to test the contributions of utrophin or α7 integrin. We show that sarcospan-mediated amelioration of muscular dystrophy in DMD mice is dependent on the presence of both utrophin and α7β1 integrin, even when they are individually expressed at therapeutic levels. Furthermore, we found that association of sarcospan into laminin-binding complexes is dependent on utrophin and α7β1 integrin.

Laminin α2 Chain-Deficiency is Associated with microRNA Deregulation in Skeletal Muscle and Plasma

microRNAs (miRNAs) are widespread regulators of gene expression, but little is known of their potential roles in congenital muscular dystrophy type 1A (MDC1A). MDC1A is a severe form of muscular dystrophy caused by mutations in the gene encoding laminin α2 chain. To gain insight into the pathophysiological roles of miRNAs associated with MDC1A pathology, laminin α2 chain-deficient mice were evaluated by quantitative PCR. We demonstrate that expression of muscle-specific miR-1, miR-133a, and miR-206 is deregulated in laminin α2 chain-deficient muscle. Furthermore, expression of miR-223 and miR-21, associated with immune cell infiltration and fibrosis, respectively, is altered. Finally, we show that plasma levels of muscle-specific miRNAs are markedly elevated in laminin α2 chain-deficient mice and partially normalized in response to proteasome inhibition therapy. Altogether, our data suggest important roles for miRNAs in MDC1A pathology and we propose plasma levels of muscle-specific miRNAs as promising biomarkers for the progression of MDC1A.

PKCζ regulates Notch receptor routing and activity in a Notch signaling-dependent manner

Activation of Notch signaling requires intracellular routing of the receptor, but the mechanisms controlling the distinct steps in the routing process is poorly understood. We identify PKCζ as a key regulator of Notch receptor intracellular routing. When PKCζ was inhibited in the developing chick central nervous system and in cultured myoblasts, Notch-stimulated cells were allowed to undergo differentiation. PKCζ phosphorylates membrane-tethered forms of Notch and regulates two distinct routing steps, depending on the Notch activation state. When Notch is activated, PKCζ promotes re-localization of Notch from late endosomes to the nucleus and enhances production of the Notch intracellular domain, which leads to increased Notch activity. In the non-activated state, PKCζ instead facilitates Notch receptor internalization, accompanied with increased ubiquitylation and interaction with the endosomal sorting protein Hrs. Collectively, these data identify PKCζ as a key regulator of Notch trafficking and demonstrate that distinct steps in intracellular routing are differentially modulated depending on Notch signaling status.

Bortezomib partially improves laminin α2 chain-deficient muscular dystrophy

Congenital muscular dystrophy, caused by mutations in LAMA2 (the gene encoding laminin α2 chain), is a severe and incapacitating disease for which no therapy is yet available. We have recently demonstrated that proteasome activity is increased in laminin α2 chain-deficient muscle and that treatment with the nonpharmaceutical proteasome inhibitor MG-132 reduces muscle pathology in laminin α2 chain-deficient dy(3K)/dy(3K) mice. Here, we explore the use of the selective and therapeutic proteasome inhibitor bortezomib (currently used for treatment of relapsed multiple myeloma and mantle cell lymphoma) in dy(3K)/dy(3K) mice and in congenital muscular dystrophy type 1A muscle cells. Outcome measures included quantitative muscle morphology, gene and miRNA expression analyses, proteasome activity, motor activity, and survival. Bortezomib improved several histological hallmarks of disease, partially normalized miRNA expression (miR-1 and miR-133a), and enhanced body weight, locomotion, and survival of dy(3K)/dy(3K) mice. In addition, bortezomib reduced proteasome activity in congenital muscular dystrophy type 1A myoblasts and myotubes. These findings provide evidence that the proteasome inhibitor bortezomib partially reduces laminin α2 chain-deficient muscular dystrophy. Investigation of the clinical efficacy of bortezomib administration in congenital muscular dystrophy type 1A clinical trials may be warranted.

Loss of dystrophin and β-sarcoglycan significantly exacerbates the phenotype of laminin α2 chain-deficient animals

The adhesion molecule laminin α2 chain interacts with the dystrophin-glycoprotein complex, contributes to normal muscle function, and protects skeletal muscles from damage. Complete loss of the laminin α2 chain in mice results in a severe muscular dystrophy phenotype and death at approximately 3 weeks of age. However, it is not clear if the remaining members of the dystrophin-glycoprotein complex further protect laminin α2 chain-deficient skeletal muscle fibers from degeneration. Hence, we generated mice deficient in laminin α2 chain and dystrophin (dy(3K)/mdx) and mice devoid of laminin α2 chain and β-sarcoglycan (dy(3K)/Sgcb). Severe muscular dystrophy and a lack of nourishment inevitably led to massive muscle wasting and death in double-knockout animals. The dy(3K)/Sgcb mice were generally more severely affected than dy(3K)/mdx mice. However, both double-knockout strains displayed exacerbated muscle degeneration, inflammation, fibrosis, and reduced life span (5 to 13 days) compared with single-knockout animals. However, neither extraocular nor cardiac muscle was affected in double-knockout animals. Our results suggest that, although laminin α2 chain, dystrophin, and β-sarcoglycan are all part of the same adhesion complex, they have complementary, but nonredundant, roles in maintaining sarcolemmal integrity and protecting skeletal muscle fibers from damage. Moreover, the double-knockout mice could potentially serve as models in which to study extremely aggressive muscle-wasting conditions.

NCoR controls glioblastoma tumor cell characteristics

Background

We have previously shown that the transcriptional coregulator NCoR represses astrocytic differentiation of neural stem cells, suggesting that NCoR could be a plausible target for differentiation therapy of glioblastoma.

Methods

To study a putative role for NCoR in regulating glioblastoma cell characteristics, we used RNA-mediated knockdown followed by analysis of gene expression, proliferation and cell growth, autophagy, invasiveness in vitro, and tumor formation in vitro and in vivo. We further performed chromatin immunoprecipitation of NCoR followed by genome-wide sequencing in the human glioblastoma cell line U87 in order to reveal NCoR-occupied loci.

Results

RNA knockdown of NCoR resulted in a moderate increase in differentiation accompanied by a significant decrease in proliferation in adherent U87 human glioblastoma cells. chromatin immunoprecipitation sequencing approach revealed alternative mechanisms underlying the decrease in proliferation, as NCoR was enriched at promoters of genes associated with autophagy such as ULK3. Indeed, signs of an autophagy response in adherent glioblastoma cells included an increased expression of autophagy genes, such as Beclin1, and increased lipidation and nuclear puncta of LC3. Intriguingly, in parallel to the effects in the adherent cells, NCoR knockdown resulted in a significant increase in anchorage-independent growth, and this glioblastoma cell population showed dramatic increases in invasive properties in vitro and tumor formation capacity in vitro and in vivo along with an increased proliferation rate.

Conclusion

Our results unveil unexpected aspects of NCoR regulation of tumor characteristics in glioblastoma cells and highlight the need for caution when transposing developmental concepts directly to cancer therapy.

Population structure and residency of whale sharks Rhincodon typus at Utila, Bay Islands, Honduras

There were 479 reported whale shark Rhincodon typus encounters between 1999 and 2011 at the island of Utila, which forms part of the Meso-American Barrier Reef System (MBRS) in the western Caribbean Sea. The majority of R. typus were found to feed on small bait fish associated with various tuna species. Ninety-five individual R. typus, ranging from 2 to 11 m total length (LT ), were identified through their unique spot patterns. A significant male bias (65%) was present. There was no significant difference between the mean ± s.d. LT of female (6·66 ± 1·65 m) and male (6·25 ± 1·60 m) R. typus. Most R. typus were transient to Utila, with 78% sighted only within a single calendar year, although some individuals were sighted in up to 5 years. Mean residency time was modelled to be 11·76 days using maximum likelihood methods.

Abstract PR12: CHD5 is required for neurogenesis and has a dual role in facilitating gene expression and Polycomb gene repression

The chromatin remodeler CHD5 is expressed in neural tissues and is frequently deleted in aggressive neuroblastoma. Very little is known about the normal function of CHD5, its mechanism of action or how its deletion may contribute to neuroblastoma. Here we report that depletion of CHD5 in the developing murine neocortex blocks neuronal differentiation leading to an accumulation of undifferentiated progenitors. Consistent with this, ChIP-SEQ analysis of CHD5 shows it binds a large cohort of neuronal genes and is required for facilitating their activation during differentiation. However, CHD5 also binds a cohort of Polycomb target genes and is required for the maintenance of H3K27me3 on their promoters and their sustained repression during differentiation. Finally, we show that the chromodomains of CHD5 directly bind H3K27me3 and are essential for the function of CHD5 during neuronal differentiation. These findings provide new insights into the essential role of CHD5 during neurogenesis and show how the inactivation of this candidate tumor suppressor might contribute to the progression of neuroblastoma via a defect in differentiation.

This abstract is also presented as Poster A05.

Citation Format: Christopher M. Egan, Ulrika Nyman, Julie Skotte, Gundula Streubel, Siobhán Turner, David J. O'Connell, Vilma Rraklli, Michael J. Dolan, Naomi Chadderton, Hansen Klaus, Farrar Gwyneth Jane, Kristian Helin, Johan Holmberg, Adrian P. Bracken. CHD5 is required for neurogenesis and has a dual role in facilitating gene expression and Polycomb gene repression. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Jun 19-22, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2013;73(13 Suppl):Abstract nr PR12.

Battery-Less Wireless Instrumented Knee Implant

Over 400,000 total knee replacement procedures (TKR) are performed annually in the United States. This paper focuses on the development of a battery-less wireless instrumented tibial tray for performance feedback in TKR implants. The proposed instrumented tibial tray is powered internally by an integrated piezoelectric energy harvesting system. Energy is harvested during the walking of the patient when forces are exerted on the tibial component. The sensors and wireless electronics are entirely powered from the harvested energy. This tibial tray is also instrumented with capacitive force sensors and an ultra low-power method to measure the capacitive force sensors. A bench top test rig is developed for testing the battery-less wireless knee replacement implant. For a person with a body weight of 55 kg, the energy harvesting system can fully charge the storage capacitors in 11 steps and can harvest an average of 1051 μJ per step. To power the force measurement system for ten seconds and to transmit the data, the piezoelectric energy harvesting system must be charged before the force measurement process is initiated by a minimum of 11 steps and a minimum of two steps must be taken during the force measurement process. During the force measurement process, each force sensor is sampled at a frequency of 10 Hz for ten seconds; thereafter, all of the data is transmitted to the RF base station. The resulting capacitive force sensors adequately represented cyclic loads; however, the sensors demonstrated some issues with repeatability.

Laminin-211 in skeletal muscle function

A chain is no stronger than its weakest link is an old idiom that holds true for muscle biology. As the name implies, skeletal muscle's main function is to move the bones. However, for a muscle to transmit force and withstand the stress that contractions give rise to, it relies on a chain of proteins attaching the cytoskeleton of the muscle fiber to the surrounding extracellular matrix. The importance of this attachment is illustrated by a large number of muscular dystrophies caused by interruption of the cytoskeletal-extracellular matrix interaction. One of the major components of the extracellular matrix is laminin, a heterotrimeric glycoprotein and a major constituent of the basement membrane. It has become increasingly apparent that laminins are involved in a multitude of biological functions, including cell adhesion, differentiation, proliferation, migration and survival. This review will focus on the importance of laminin-211 for normal skeletal muscle function.

Sarcospan-dependent Akt activation is required for utrophin expression and muscle regeneration

Utrophin is normally confined to the neuromuscular junction (NMJ) in adult muscle and partially compensates for the loss of dystrophin in mdx mice. We show that Akt signaling and utrophin levels were diminished in sarcospan (SSPN)-deficient muscle. By creating several transgenic and knockout mice, we demonstrate that SSPN regulates Akt signaling to control utrophin expression. SSPN determined α-dystroglycan (α-DG) glycosylation by affecting levels of the NMJ-specific glycosyltransferase Galgt2. After cardiotoxin (CTX) injury, regenerating myofibers express utrophin and Galgt2-modified α-DG around the sarcolemma. SSPN-null mice displayed delayed differentiation after CTX injury caused by loss of utrophin and Akt signaling. Treatment of SSPN-null mice with viral Akt increased utrophin and restored muscle repair after injury, revealing an important role for the SSPN-Akt-utrophin signaling axis in regeneration. SSPN improved cell surface expression of utrophin by increasing transportation of utrophin and DG from endoplasmic reticulum/Golgi membranes. Our experiments reveal functions of utrophin in regeneration and new pathways that regulate utrophin expression at the cell surface.