SRF-deficient astrocytes provide neuroprotection in mouse models of excitotoxicity and neurodegeneration

Reactive astrogliosis is a common pathological hallmark of CNS injury, infection, and neurodegeneration, where reactive astrocytes can be protective or detrimental to normal brain functions. Currently, the mechanisms regulating neuroprotective astrocytes and the extent of neuroprotection are poorly understood. Here, we report that conditional deletion of serum response factor (SRF) in adult astrocytes causes reactive-like hypertrophic astrocytes throughout the mouse brain. These SrfGFAP-ERCKO astrocytes do not affect neuron survival, synapse numbers, synaptic plasticity or learning and memory. However, the brains of Srf knockout mice exhibited neuroprotection against kainic-acid induced excitotoxic cell death. Relevant to human neurodegenerative diseases, SrfGFAP-ERCKO astrocytes abrogate nigral dopaminergic neuron death and reduce β-amyloid plaques in mouse models of Parkinson's and Alzheimer's disease, respectively. Taken together, these findings establish SRF as a key molecular switch for the generation of reactive astrocytes with neuroprotective functions that attenuate neuronal injury in the setting of neurodegenerative diseases.

Epilepsy Characteristics in Neurodevelopmental Disorders: Research from Patient Cohorts and Animal Models Focusing on Autism Spectrum Disorder

Epilepsy, a heterogeneous group of brain-related diseases, has continued to significantly burden society and families. Epilepsy comorbid with neurodevelopmental disorders (NDDs) is believed to occur due to multifaceted pathophysiological mechanisms involving disruptions in the excitation and inhibition (E/I) balance impeding widespread functional neuronal circuitry. Although the field has received much attention from the scientific community recently, the research has not yet translated into actionable therapeutics to completely cure epilepsy, particularly those comorbid with NDDs. In this review, we sought to elucidate the basic causes underlying epilepsy as well as those contributing to the association of epilepsy with NDDs. Comprehensive emphasis is put on some key neurodevelopmental genes implicated in epilepsy, such as MeCP2, SYNGAP1, FMR1, SHANK1-3 and TSC1, along with a few others, and the main electrophysiological and behavioral deficits are highlighted. For these genes, the progress made in developing appropriate and valid rodent models to accelerate basic research is also detailed. Further, we discuss the recent development in the therapeutic management of epilepsy and provide a briefing on the challenges and caveats in identifying and testing species-specific epilepsy models.

A perspective on molecular signalling dysfunction, its clinical relevance and therapeutics in autism spectrum disorder

Intellectual disability (ID) and autism spectrum disorder (ASD) are neurodevelopmental disorders that have become a primary clinical and social concern, with a prevalence of 2-3% in the population. Neuronal function and behaviour undergo significant malleability during the critical period of development that is found to be impaired in ID/ASD. Human genome sequencing studies have revealed many genetic variations associated with ASD/ID that are further verified by many approaches, including many mouse and other models. These models have facilitated the identification of fundamental mechanisms underlying the pathogenesis of ASD/ID, and several studies have proposed converging molecular pathways in ASD/ID. However, linking the mechanisms of the pathogenic genes and their molecular characteristics that lead to ID/ASD has progressed slowly, hampering the development of potential therapeutic strategies. This review discusses the possibility of recognising the common molecular causes for most ASD/ID based on studies from the available models that may enable a better therapeutic strategy to treat ID/ASD. We also reviewed the potential biomarkers to detect ASD/ID at early stages that may aid in diagnosis and initiating medical treatment, the concerns with drug failure in clinical trials, and developing therapeutic strategies that can be applied beyond a particular mutation associated with ASD/ID.

Pharmacological intervention in young adolescents rescues synaptic physiology and behavioural deficits in Syngap1+/- mice

Haploinsufficiency in SYNGAP1 is implicated in intellectual disability (ID) and autism spectrum disorder (ASD) and affects the maturation of dendritic spines. The abnormal spine development has been suggested to cause a disbalance of excitatory and inhibitory (E/I) neurotransmission at distinct developmental periods. In addition, E/I imbalances in Syngap1^+/- mice might be due to abnormalities in K⁺-Cl^- co-transporter function (NKCC1, KCC2), in a maner similar to the murine models of Fragile-X and Rett syndromes. To study whether an altered intracellular chloride ion concentration represents an underlying mechanism of modified function of GABAergic synapses in Dentate Gyrus Granule Cells of Syngap1^+/- recordings were performed at different developmental stages of the mice. We observed depolarised neurons at P14-15 as illustrated by decreased Cl^- reversal potential in Syngap1^+/- mice. The KCC2 expression was decreased compared to Wild-type (WT) mice at P14-15. The GSK-3β inhibitor, 6-bromoindirubin-3'-oxime (6BIO) that crosses the blood-brain barrier, was tested to restore the function of GABAergic synapses. We discovered that the intraperitoneal administration of 6BIO during the critical period or young adolescents [P30 to P80 (4-week to 10-week)] normalised an altered E/I balance, the deficits of synaptic plasticity, and behavioural performance like social novelty, anxiety, and memory of the Syngap1^+/- mice. In summary, altered GABAergic function in Syngap1^+/- mice is due to reduced KCC2 expression leading to an increase in the intracellular chloride concentration that can be counteracted by the 6BIO, which restored cognitive, emotional, and social symptoms by pharmacological intervention, particularly in adulthood.

Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling

Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3' UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity.

Critical aspects of neurodevelopment

Organisms have the unique ability to adapt to their environment by making use of external inputs. In the process, the brain is shaped by experiences that go hand-in-hand with optimisation of neural circuits. As such, there exists a time window for the development of different brain regions, each unique for a particular sensory modality, wherein the propensity of forming strong, irreversible connections are high, referred to as a critical period of development. Over the years, this domain of neurodevelopmental research has garnered considerable attention from many scientists, primarily because of the intensive activity-dependent nature of development. This review discusses the cellular, molecular, and neurophysiological bases of critical periods of different sensory modalities, and the disorders associated in cases the regulators of development are dysfunctional. Eventually, the neurobiological bases of the behavioural abnormalities related to developmental pathologies are discussed. A more in-depth insight into the development of the brain during the critical period of plasticity will eventually aid in developing potential therapeutics for several neurodevelopmental disorders that are categorised under critical period disorders.

Spatiotemporal analysis of soluble aggregates and autophagy markers in the R6/2 mouse model

Maintenance of cellular proteostasis is vital for post-mitotic cells like neurons to sustain normal physiological function and homeostasis, defects in which are established hallmarks of several age-related conditions like AD, PD, HD, and ALS. The Spatio-temporal accumulation of aggregated proteins in the form of inclusion bodies/plaques is one of the major characteristics of many neurodegenerative diseases, including Huntington's disease (HD). Toxic accumulation of HUNTINGTIN (HTT) aggregates in neurons bring about the aberrant phenotypes of HD, including severe motor dysfunction, dementia, and cognitive impairment at the organismal level, in an age-dependent manner. In several cellular and animal models, aggrephagy induction has been shown to clear aggregate-prone proteins like HTT and ameliorate disease pathology by conferring neuroprotection. In this study, we used the mouse model of HD, R6/2, to understand the pathogenicity of mHTT aggregates, primarily focusing on autophagy dysfunction. We report that basal autophagy is not altered in R6/2 mice, whilst being functional at a steady-state level in neurons. Moreover, we tested the efficacy of a known autophagy modulator, Nilotinib (Tasigna™), presently in clinical trials for PD, and HD, in curbing mHTT aggregate growth and their potential clearance, which was ineffective in both inducing autophagy and rescuing the pathological phenotypes in R6/2 mice.

Chronic postnatal chemogenetic activation of forebrain excitatory neurons evokes persistent changes in mood behavior

Early adversity is a risk factor for the development of adult psychopathology. Common across multiple rodent models of early adversity is increased signaling via forebrain Gq-coupled neurotransmitter receptors. We addressed whether enhanced Gq-mediated signaling in forebrain excitatory neurons during postnatal life can evoke persistent mood-related behavioral changes. Excitatory hM3Dq DREADD-mediated chemogenetic activation of forebrain excitatory neurons during postnatal life (P2–14), but not in juvenile or adult windows, increased anxiety-, despair-, and schizophrenia-like behavior in adulthood. This was accompanied by an enhanced metabolic rate of cortical and hippocampal glutamatergic and GABAergic neurons. Furthermore, we observed reduced activity and plasticity-associated marker expression, and perturbed excitatory/inhibitory currents in the hippocampus. These results indicate that Gq-signaling-mediated activation of forebrain excitatory neurons during the critical postnatal window is sufficient to program altered mood-related behavior, as well as functional changes in forebrain glutamate and GABA systems, recapitulating aspects of the consequences of early adversity.

Stress and adversity in early childhood can have long-lasting effects, predisposing people to mental illness and mood disorders in adult life. The weeks immediately before and after birth are critical for establishing key networks of neurons in the brain. Therefore, any disruption to these neural circuits during this time can be detrimental to emotional development. However, it is still unclear which cellular mechanisms cause these lasting changes in behavior.

Studies in animals suggest that these long-term effects could result from abnormalities in a few signaling pathways in the brain. For example, it has been proposed that overstimulating the cells that activate circuits in the forebrain – also known as excitatory neurons – may contribute to the behavioral changes that persist into adulthood.

To test this theory, Pati et al. used genetic engineering to modulate a signaling pathway in male mice, which is known to stimulate excitatory neurons in the forebrain. The experiments showed that prolonged activation of excitatory neurons in the first two weeks after birth resulted in anxious and despair-like behaviors as the animals aged. The mice also displayed discrepancies in how they responded to certain external sensory information, which is a hallmark of schizophrenia-like behavior. However, engineering the same changes in adolescent and adult mice had no effect on their mood-related behaviors.

This animal study reinforces just how critical the first few weeks of life are for optimal brain development. It provides an insight into a possible mechanism of how disruption during this time could alter emotional behavior. The findings are also relevant to psychiatrists interested in the underlying causes of mental illness after early childhood adversity.

Small molecule modulator of aggrephagy regulates neuroinflammation to curb pathogenesis of neurodegeneration

Background

Plethora of efforts fails to yield a single drug to reverse the pathogenesis of Parkinson's disease (PD) and related α-synucleopathies.

Methods

Using chemical biology, we identified a small molecule inhibitor of c-abl kinase, PD180970 that could potentially clear the toxic protein aggregates. Genetic, molecular, cell biological and immunological assays were performed to understand the mechanism of action. In vivo preclinical disease model of PD was used to assess its neuroprotection efficacy.

Findings

In this report, we show the ability of a small molecule inhibitor of tyrosine kinases, PD180970, to induce autophagy (cell lines and mice midbrain) in an mTOR-independent manner and ameliorate the α-synuclein mediated toxicity. PD180970 also exerts anti-neuroinflammatory potential by inhibiting the release of proinflammatory cytokines such as IL-6 (interleukin-6) and MCP-1 (monocyte chemoattractant protein-1) through reduction of TLR-4 (toll like receptor-4) mediated NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation. In vivo studies show that PD180970 is neuroprotective by degrading the toxic protein oligomers through induction of autophagy and subsiding the microglial activation.

Interpretation

These protective mechanisms ensure the negation of Parkinson's disease related motor impairments.

Fund

This work was supported by Wellcome Trust/DBT India Alliance Intermediate Fellowship (500159-Z-09-Z), DST-SERB grant (EMR/2015/001946), DBT (BT/INF/22/SP27679/2018) and JNCASR intramural funds to RM, and SERB, DST (SR/SO/HS/0121/2012) to PAA, and DST-SERB (SB/YS/LS-215/2013) to JPC and BIRAC funding to ETA C-CAMP.

Understanding intellectual disability and autism spectrum disorders from common mouse models: synapses to behaviour

Normal brain development is highly dependent on the timely coordinated actions of genetic and environmental processes, and an aberration can lead to neurodevelopmental disorders (NDDs). Intellectual disability (ID) and autism spectrum disorders (ASDs) are a group of co-occurring NDDs that affect between 3% and 5% of the world population, thus presenting a great challenge to society. This problem calls for the need to understand the pathobiology of these disorders and to design new therapeutic strategies. One approach towards this has been the development of multiple analogous mouse models. This review discusses studies conducted in the mouse models of five major monogenic causes of ID and ASDs: Fmr1, Syngap1, Mecp2, Shank2/3 and Neuroligins/Neurnexins. These studies reveal that, despite having a diverse molecular origin, the effects of these mutations converge onto similar or related aetiological pathways, consequently giving rise to the typical phenotype of cognitive, social and emotional deficits that are characteristic of ID and ASDs. This convergence, therefore, highlights common pathological nodes that can be targeted for therapy. Other than conventional therapeutic strategies such as non-pharmacological corrective methods and symptomatic alleviation, multiple studies in mouse models have successfully proved the possibility of pharmacological and genetic therapy enabling functional recovery.

Differential Regulation of Syngap1 Translation by FMRP Modulates eEF2 Mediated Response on NMDAR Activity

SYNGAP1, a Synaptic Ras-GTPase activating protein, regulates synapse maturation during a critical developmental window. Heterozygous mutation in SYNGAP1 (SYNGAP1 ^-/+) has been shown to cause Intellectual Disability (ID) in children. Recent studies have provided evidence for altered neuronal protein synthesis in a mouse model of Syngap1 ^-/+. However, the molecular mechanism behind the same is unclear. Here, we report the reduced expression of a known translation regulator, FMRP, during a specific developmental period in Syngap1 ^-/+ mice. Our results demonstrate that FMRP interacts with and regulates the translation of Syngap1 mRNA. We further show reduced Fmr1 translation leads to decreased FMRP level during development in Syngap1 ^-/+ which results in an increase in Syngap1 translation. These developmental changes are reflected in the altered response of eEF2 phosphorylation downstream of NMDA Receptor (NMDAR)-mediated signaling. In this study, we propose a cross-talk between FMRP and SYNGAP1 mediated signaling which can also explain the compensatory effect of impaired signaling observed in Syngap1 ^-/+ mice.

Neurodegenerative diseases: model organisms, pathology and autophagy

A proteostasis view of neurodegeneration (ND) identifies protein aggregation as a leading causative reason for damage seen at the cellular and organ levels. While investigative therapies that aim at dissolving aggregates have failed, and the promises of silencing expression of ND associated pathogenic proteins or the deployment of engineered induced pluripotent stem cells (iPSCs) are still in the horizon, emerging literature suggests degrading aggregates through autophagy-related mechanisms hold the current potential for a possible cure. Macroautophagy (hereafter autophagy) is an intracellular degradative pathway where superfluous or unwanted cellular cargoes (such as peroxisomes, mitochondria, ribosomes, intracellular bacteria and misfolded protein aggregates) are wrapped in double membrane vesicles called autophagosomes that eventually fuses with lysosomes for their degradation. The selective branch of autophagy that deals with identification, capture and degradation of protein aggregates is called aggrephagy. Here, we cover the workings of aggrephagy detailing its selectivity towards aggregates. The diverse cellular adaptors that bridge the aggregates with the core autophagy machinery in terms of autophagosome formation are discussed. In ND, essential protein quality control mechanisms fail as the constituent components also find themselves trapped in the aggregates. Thus, although cellular aggrephagy has the potential to be upregulated, its dysfunction further aggravates the pathogenesis. This phenomenonwhen combined with the fact that neurons can neither dilute out the aggregates by cell division nor the dead neurons can be replaced due to low neurogenesis, makes a compelling case for aggrephagy pathway as a potential therapeutic option.

Modulation of Autophagy by a Small Molecule Inverse Agonist of ERRα Is Neuroprotective

Mechanistic insights into aggrephagy, a selective basal autophagy process to clear misfolded protein aggregates, are lacking. Here, we report and describe the role of Estrogen Related Receptor α (ERRα, HUGO Gene Nomenclature ESRRA), new molecular player of aggrephagy, in keeping autophagy flux in check by inhibiting autophagosome formation. A screen for small molecule modulators for aggrephagy identified ERRα inverse agonist XCT 790, that cleared α-synuclein aggregates in an autophagy dependent, but mammalian target of rapamycin (MTOR) independent manner. XCT 790 modulates autophagosome formation in an ERRα dependent manner as validated by siRNA mediated knockdown and over expression approaches. We show that, in a basal state, ERRα is localized on to the autophagosomes and upon autophagy induction by XCT 790, this localization is lost and is accompanied with an increase in autophagosome biogenesis. In a preclinical mouse model of Parkinson's disease (PD), XCT 790 exerted neuroprotective effects in the dopaminergic neurons of nigra by inducing autophagy to clear toxic protein aggregates and, in addition, ameliorated motor co-ordination deficits. Using a chemical biology approach, we unrevealed the role of ERRα in regulating autophagy and can be therapeutic target for neurodegeneration.

A novel autophagy modulator 6-Bio ameliorates SNCA/α-synuclein toxicity

Parkinson disease (PD) is a life-threatening neurodegenerative movement disorder with unmet therapeutic intervention. We have identified a small molecule autophagy modulator, 6-Bio that shows clearance of toxic SNCA/α-synuclein (a protein implicated in synucleopathies) aggregates in yeast and mammalian cell lines. 6-Bio induces autophagy and dramatically enhances autolysosome formation resulting in SNCA degradation. Importantly, neuroprotective function of 6-Bio as envisaged by immunohistology and behavior analyses in a preclinical model of PD where it induces autophagy in dopaminergic (DAergic) neurons of mice midbrain to clear toxic protein aggregates suggesting that it could be a potential therapeutic candidate for protein conformational disorders.

Metabotropic action of postsynaptic kainate receptors triggers hippocampal long-term potentiation

Long-term potentiation (LTP) in the rat hippocampus is the most extensively studied cellular model for learning and memory. Induction of classical LTP involves an NMDA-receptor- and calcium-dependent increase in functional synaptic AMPA receptors, mediated by enhanced recycling of internalized AMPA receptors back to the postsynaptic membrane. Here we report a physiologically relevant NMDA-receptor-independent mechanism that drives increased AMPA receptor recycling and LTP. This pathway requires the metabotropic action of kainate receptors and activation of G protein, protein kinase C and phospholipase C. Like classical LTP, kainate-receptor-dependent LTP recruits recycling endosomes to spines, enhances synaptic recycling of AMPA receptors to increase their surface expression and elicits structural changes in spines, including increased growth and maturation. These data reveal a new and, to our knowledge, previously unsuspected role for postsynaptic kainate receptors in the induction of functional and structural plasticity in the hippocampus.

SYNGAP1: Mind the Gap

A cardinal feature of early stages of human brain development centers on the sensory, cognitive, and emotional experiences that shape neuronal-circuit formation and refinement. Consequently, alterations in these processes account for many psychiatric and neurodevelopmental disorders. Neurodevelopment disorders affect 3-4% of the world population. The impact of these disorders presents a major challenge to clinicians, geneticists, and neuroscientists. Mutations that cause neurodevelopmental disorders are commonly found in genes encoding proteins that regulate synaptic function. Investigation of the underlying mechanisms using gain or loss of function approaches has revealed alterations in dendritic spine structure, function, and plasticity, consequently modulating the neuronal circuit formation and thereby raising the possibility of neurodevelopmental disorders resulting from synaptopathies. One such gene, SYNGAP1 (Synaptic Ras-GTPase-activating protein) has been shown to cause Intellectual Disability (ID) with comorbid Autism Spectrum Disorder (ASD) and epilepsy in children. SYNGAP1 is a negative regulator of Ras, Rap and of AMPA receptor trafficking to the postsynaptic membrane, thereby regulating not only synaptic plasticity, but also neuronal homeostasis. Recent studies on the neurophysiology of SYNGAP1, using Syngap1 mouse models, have provided deeper insights into how downstream signaling proteins and synaptic plasticity are regulated by SYNGAP1. This knowledge has led to a better understanding of the function of SYNGAP1 and suggests a potential target during critical period of development when the brain is more susceptible to therapeutic intervention.

Pathogenic SYNGAP1 mutations impair cognitive development by disrupting maturation of dendritic spine synapses

Mutations that cause intellectual disability (ID) and autism spectrum disorder (ASD) are commonly found in genes that encode for synaptic proteins. However, it remains unclear how mutations that disrupt synapse function impact intellectual ability. In the SYNGAP1 mouse model of ID/ASD, we found that dendritic spine synapses develop prematurely during the early postnatal period. Premature spine maturation dramatically enhanced excitability in the developing hippocampus, which corresponded with the emergence of behavioral abnormalities. Inducing SYNGAP1 mutations after critical developmental windows closed had minimal impact on spine synapse function, whereas repairing these pathogenic mutations in adulthood did not improve behavior and cognition. These data demonstrate that SynGAP protein acts as a critical developmental repressor of neural excitability that promotes the development of life-long cognitive abilities. We propose that the pace of dendritic spine synapse maturation in early life is a critical determinant of normal intellectual development.

Proposed diagnostic criteria for apathy in Alzheimer's disease and other neuropsychiatric disorders

There is wide acknowledgement that apathy is an important behavioural syndrome in Alzheimer's disease and in various neuropsychiatric disorders. In light of recent research and the renewed interest in the correlates and impacts of apathy, and in its treatments, it is important to develop criteria for apathy that will be widely accepted, have clear operational steps, and that will be easily applied in practice and research settings. Meeting these needs is the focus of the task force work reported here. The task force includes members of the Association Française de Psychiatrie Biologique, the European Psychiatric Association, the European Alzheimer's Disease Consortium and experts from Europe, Australia and North America. An advanced draft was discussed at the consensus meeting (during the EPA conference in April 7th 2008) and a final agreement reached concerning operational definitions and hierarchy of the criteria. Apathy is defined as a disorder of motivation that persists over time and should meet the following requirements. Firstly, the core feature of apathy, diminished motivation, must be present for at least four weeks; secondly two of the three dimensions of apathy (reduced goal-directed behaviour, goal-directed cognitive activity, and emotions) must also be present; thirdly there should be identifiable functional impairments attributable to the apathy. Finally, exclusion criteria are specified to exclude symptoms and states that mimic apathy.

Rats smell in stereo

It has been hypothesized that rats and other mammals can use stereo cues to localize odor sources, but there is limited behavioral evidence to support this hypothesis. We found that rats trained on an odor-localization task can localize odors accurately in one or two sniffs. Bilateral sampling was essential for accurate odor localization, with internasal intensity and timing differences as directional cues. If the stimulus arrived at the correct point of the respiration cycle, internasal timing differences as short as 50 milliseconds sufficed. Neuronal recordings show that bulbar neurons responded differentially to stimuli from the left and stimuli from the right.

[Comparison of sociocultural attitudes towards epilepsy in Limousin (France), in Togo and in Benin (Africa)]

Sociocultural attitudes continue to have a negative impact on management of epilepsy in many African countries and in a few advanced countries. The purpose of this study was to compare attitudes toward epilepsy in France and two African nations: Togo and Benin. A total of 305 epileptic patients over 18 years of age were interviewed using the same quantitative questionnaire about their beliefs, knowledge attitudes and practices regarding their disease. There were 77 patients from the Limousin region in France, 129 from the rural canton of Nadoba in Togo and 99 from the coastal province in Benin. The frequency of epileptic seizure during the last two years prior to the study was lower in France than in Togo and Benin. The number of people who believed in supernatural causes of epilepsy was higher in Togo and Benin whereas the number of people attributing the disease to social causes (e.g. death and stress) was higher in France. Few epileptic patients in France thought that the disease was contagious whereas many patients in both Togo and Benin still believed that the disease was contagious and that some foods were forbidden. More patients in France than in Togo and Benin were aware of the relationship of epilepsy with alcohol, drug abuse and cerebral injury. Epileptic patients in France were more likely to consult a physician and use medical drugs for the treatment of epilepsy than their counterparts in Togo and Benin. Epileptic patients in Togo often complained of social exclusion. Although sometimes contradictory, these findings support the idea that sociocultural attitudes should be taken into account in the management of the disease.

HMO penetration: has it hurt public hospitals?

The purpose of this study is to determine the extent to which health maintenance organization (HMO) penetration within the public hospitals' market area affects the financial performance and viability of these institutions, relative to private hospitals. Hospital- and market-specific measures are examined in a fully interacted model of over 2,300 hospitals in 321 metropolitan statistical areas (MSAs) in 1995. Although hospitals located in markets with higher HMO penetration have lower financial performance as reflected in revenues, expenses and operating margin, public hospitals are not more disadvantaged than other hospitals by managed care.

Going the distance: the evolution of VCU's Executive Distance Learning Program over 12 years

Drawing upon the twelve-year history of Virginia Commonwealth University's (VCU) online distance learning Executive Program, this article identifies factors important to the success of online distance learning and major changes in distance learning over time. It discusses curriculum, instructional design, technology infrastructure and support, educational strategy and pedagogy, faculty, and student program dimensions. As one of the oldest online health administration or business programs, the Executive Program at VCU and this examination thereof are particularly suited to identify significant lessons learned from experience with online education. The article concludes with a summary of challenges facing this and other distance learning programs in health administration.

Strategic hospital alliances: do the type and market structure of strategic hospital alliances matter?

BACKGROUND

Throughout the 1990s, hospitals formed local alliances to defend against increasingly powerful hospital rivals and to improve their market positions relative to aggressive and consolidating managed-care organizations. An important consequence of hospitals combining or aligning horizontally at the local level is a significant consolidation of hospital markets.

OBJECTIVE

The aim of this study was to examine the relationship between the type of the local strategic hospital alliances (SHAs), market, environment, and operational factors with financial performance.

METHODS

The study is a cross-sectional analysis of the financial performance across SHAs in all metropolitan statistical areas in 1995.

RESULTS

SHAs with dominant or dominant for-profit (FP) hospitals are not more financially successful than other SHAs. SHAs in markets with high health maintenance organization (HMO) or SHA penetration have lower revenues per case-mix adjusted discharge. The operational characteristics, proportion of teaching members in the SHA, and SHA bed size, result in higher revenues and expenses, whereas greater SHA technical efficiency results in lower costs.

CONCLUSIONS

Health care organizations are centralizing their operations and governance. This study shows that this trend has not added financial value to hospital collectives, at least at this point in their development.

The C terminus of SUR1 is required for trafficking of KATP channels

In beta cells from the pancreas, ATP-sensitive potassium channels, or KATP channels, are composed of two subunits, SUR1 and KIR6.2, assembled in a (SUR1/KIR6.2)4 stoichiometry. The correct stoichiometry of channels at the cell surface is tightly regulated by the presence of novel endoplasmic reticulum (ER) retention signals in SUR1 and KIR6.2; incompletely assembled KATP channels fail to exit the ER/cis-Golgi compartments. In addition to these retrograde signals, we show that the C terminus of SUR1 has an anterograde signal, composed in part of a dileucine motif and downstream phenylalanine, which is required for KATP channels to exit the ER/cis-Golgi compartments and transit to the cell surface. Deletion of as few as seven amino acids, including the phenylalanine, from SUR1 markedly reduces surface expression of KATP channels. Mutations leading to truncation of the C terminus of SUR1 are one cause of a severe, recessive form of persistent hyperinsulinemic hypoglycemia of infancy. We propose that the complete loss of beta cell KATP channel activity seen in this form of hyperinsulinism is a failure of KATP channels to traffic to the plasma membrane.

Detection of depression in elderly hospitalized patients in emergency wards in France using the CES-D and the mini-GDS: preliminary experiences

OBJECTIVE

The purpose of this study was to evaluate the mini-GDS and the CES-D as instruments to detect depression in elderly hospitalized patients in emergency wards in France.

METHODS

The CES-D was used on two cohorts of 60 non-cognitively impaired patients aged 70 or more. The mini-GDS was also used on the second of the two cohorts administered by a medical intern. These ratings were compared with a diagnosis of depressive disorder by ICD-10 criteria.

RESULTS

The study population had a high (58%) prevalence of depression and a low level of active psychiatric referral. Mini-GDS and CES-D scores were well correlated (0.72, p < 0.001); the mini-GDS, with a cutoff score of 1, gave optimum sensitivity (88%) and specificity (63%).

CONCLUSION

The use of the mini-GDS may aid the detection of depression in patients in emergency wards.

What do we want and what do we get from not-for-profit hospitals?

The tax exemption for not-for-profit hospitals has been subject to many recent challenges, in part related to concerns over whether these hospitals provide sufficient levels of community benefits to merit tax exemption. Computing the value of community benefits for California hospitals as the sum of uncompensated care, education and research, net income, money-losing services, and price discounts from for-profit hospitals reveals that 20 to 80 percent of hospitals would have met various recommended community benefits standards. There is a clear need for hospitals and their communities to establish dialogues on what levels of community benefits are appropriate.

Dynamic cost shifting in hospitals: evidence from the 1980s and 1990s

The purpose of this paper is to determine whether dynamic cost shifting occurred among acute care hospitals during the period from the early 1980s to the early 1990s and, if so, whether market factors affected the ability to shift costs. Evidence from this study of California acute care hospitals during three time intervals shows that the hospital did practice dynamic cost shifting, but that their ability to shift costs decreased over time. Surprisingly, hospital competition and HMO penetration did not influence cost shifting. However, increasing HMO penetration (measured as the HMO percentage of hospital discharges) did decrease both net prices and costs for the early part of the study, but later was associated with increases in both.

Toward understanding the assembly and structure of KATP channels

Adenosine 5'-triphosphate-sensitive potassium (KATP) channels couple metabolic events to membrane electrical activity in a variety of cell types. The cloning and reconstitution of the subunits of these channels demonstrate they are heteromultimers of inwardly rectifying potassium channel subunits (KIR6.x) and sulfonylurea receptors (SUR), members of the ATP-binding cassette (ABC) superfamily. Recent studies indicate that SUR and KIR6.x associate with 1:1 stoichiometry to assemble a large tetrameric channel, (SUR/KIR6.x)4. The KIR6.x subunits form the channel pore, whereas SUR is required for activation and regulation. Two KIR6.x genes and two SUR genes have been identified, and combinations of subunits give rise to KATP channel subtypes found in pancreatic beta-cells, neurons, and cardiac, skeletal, and smooth muscle. Mutations in both the SUR1 and KIR6.2 genes have been shown to cause familial hyperinsulinism, indicating the importance of the pancreatic beta-cell channel in the regulation of insulin secretion. The availability of cloned KATP channel genes opens the way for characterization of this family of ion channels and identification of additional genetic defects.

Strategic hospital alliances: impact on financial performance

Acute care hospitals have increasingly been forming local strategic hospital alliances (SHAs), which consume considerable resources in forming and may affect the competitiveness of provider markets. This research shows that SHAs and market factors, which have been perceived to be threats to hospitals, are related to hospitals' financial performance. Among the findings are that SHA members have higher net revenues but that they are not more effective at cost control. Nor do the higher net revenues result in higher cash flow. However, increasing SHA penetration in a market is related to lower net revenues per case. In addition, the penetration of private health maintenance organizations in markets is associated with lower revenues and expenses.

Phosphorylation of human progesterone receptor by cyclin-dependent kinase 2 on three sites that are authentic basal phosphorylation sites in vivo

The human progesterone receptor (hPR) in T47D breast cancer cells is phosphorylated on at least nine different serine residues. We have previously reported the identification of five sites; three are hormone inducible (Ser102, Ser294 and Ser345), and their phosphorylation correlates with the timing of the change in receptor mobility on gel electrophoresis in response to hormone treatment. The other two sites, Ser81 and Ser162, along with the remaining sites, are basally phosphorylated and exhibit a general increase in phosphorylation in response to hormone. With the exception of Ser81, all of these sites are in Ser-Pro motifs, suggesting that proline-directed kinases are responsible for their phosphorylation. We now report that cyclin A-cyclin-dependent kinase-2 complexes phosphorylate hPR-B in vitro with a high stoichiometry on three sites that are authentic basal sites in vivo. One of these is Ser162, which has been described previously. The other two sites are identified here as Ser190 and Ser400. The specificity and stoichiometry of the in vitro phosphorylation suggest that hPR phosphorylation may be regulated in a cell cycle-dependent manner in vivo.

Association and stoichiometry of K(ATP) channel subunits

ATP-sensitive potassium channels (K(ATP) channels) are heteromultimers of sulfonylurea receptors (SUR) and inwardly rectifying potassium channel subunits (K(IR)6.x) with a (SUR-K(IR)6.x)4 stoichiometry. Association is specific for K(IR)6.x and affects receptor glycosylation and cophotolabeling of K(IR)6.x by 125I-azidoglibenclamide. Association produces digitonin stable complexes with an estimated mass of 950 kDa. These complexes can be purified by lectin chromatography or by using Ni2(+)-agarose and a his-tagged SUR1. Expression of SUR1 approximately (K(IR)6.2)i fusion constructs shows that a 1:1 SUR1:K(IR)6.2 stoichiometry is both necessary and sufficient for assembly of active K(ATP) channels. Coexpression of a mixture of strongly and weakly rectifying triple fusion proteins, rescued by SUR1, produced the three channel types expected of a tetrameric pore.

The high-affinity sulfonylurea receptor: distribution, glycosylation, purification, and immunoprecipitation of two forms from endocrine and neuroendocrine cell lines

The high-affinity sulfonylurea receptor, a novel member of the ATP-binding cassette superfamily, is one component of the ATP-sensitive K+ channel. The protein is critical for regulation of insulin secretion from pancreatic beta-cells, and mutations in the receptor have been linked to familial hyperinsulinemia, a disorder characterized by unregulated insulin release despite severe hypoglycemia. The sulfonylurea receptor is present in membranes from a number of endocrine and neuroendocrine cell lines, including HIT-T15, RINm5f, alpha TC-6, AtT-20, and GH3 cells. Two forms of the receptor are present in RINm5f and alpha TC-6 cells, with apparent SDS gel molecular masses of 140 and 150 kDa. The two forms have equally high affinity, KD approximately 3 nM, for an iodinated derivative of glyburide, an anti-diabetic sulfonylurea. The receptor is a glycoprotein; treatment of RINm5f or alpha TC-6 cells with tunicamycin reduces the 140 and 150 kDa species to a single approximately 137 kDa protein. The 140 and 150 kDa receptors bind differentially to concanavalin A and wheat germ agglutinin, and lectin-affinity chromatography is ideal for the initial stages of receptor purification. After lectin-affinity chromatography, the same methods can be applied for purifying the 150 kDa form as for the 140 kDa receptor. A transiently expressed receptor with a histidine-tagged carboxy-terminus was purified by Ni-agarose chromatography, and this variant was used to demonstrate that the 140 kDa polypeptide is full length. Anti-peptide antibodies directed against the amino-terminus of the receptor and antibodies against the nucleotide binding folds immunoprecipitate both receptor forms. The results indicate the 140 and 150 kDa receptors are differentially glycosylated forms of the same polypeptide chain.

Mutations in the sulonylurea receptor gene are associated with familial hyperinsulinism in Ashkenazi Jews

Familial hyperinsulinism (HI) is a disorder of pancreatic beta-cell function characterized by persistent hyperinsulinism despite severe hypoglycemia. To define the molecular genetic basis of HI in Ashkenazi Jews, 25 probands were screened for mutations in the sulfonylurea receptor (SUR1) gene by single-strand conformation polymorphism (SSCP) analysis of genomic DNA and subsequent nucleotide sequence analyses. Two common mutations were identified: (I) a novel in-frame deletion of three nucleotides (nt) in exon 34, resulting in deletion of the codon for F1388 (delta F1388) and (II) a previously described g-->a transition at position-9 of the 3' splice site of intron 32 (designated 3992-9g-->a). Together, these mutations are associated with 88% of the HI chromosomes of the patients studied. 86Rb+ efflux measurements of COSm6 cells co-expressing Kir6.2 and either wild-type or delta F1388 SUR1 revealed that the F1388 mutation abolished ATP-sensitive potassium channel (KATP) activity in intact cells. Extended haplotype analyses indicated that the delta F1388 mutation was associated with a single specific haplotype whereas the 3992-9g-->a mutation was primarily associated with a single haplotype but also occurred in the context of several other different haplotypes. These data suggest that HI in Ashkenazi Jews is predominantly associated with mutations in the SUR1 gene and provide evidence for the existence of at least two founder HI chromosomes in this population.

Assessing the characteristics of hospital bond defaults

OBJECTIVES

The authors identify market, operational, and financial characteristics associated with the default of hospital revenue bonds using logistic regression analysis.

METHODS

Data from 22 defaulted hospitals and 260 nondefaulted hospitals from 1988 to 1992 are analyzed.

RESULTS

Findings indicated that defaulted hospitals had smaller market shares, were located in near-urban markets, and incurred higher expenses per discharge than nondefaulted hospitals. Defaulted hospitals also were highly leveraged and had lower debt service coverage ratios compared with nondefaulted hospitals.

CONCLUSIONS

Results suggest that market share, ability to generate sufficient case flow to meet debt service, and amount of debt on hand are critical factors in avoiding a bond default but not government payer mix.

The performance of Hospital Corporation of America and Healthtrust hospitals after leveraged buyouts

The authors examine performance changes after two leveraged buyouts (LBOs) in the hospital industry, one an employee stock ownership plan (ESOP) and the other a managed buyout (MBO). The findings show that hospitals owned by HCA, the MBO firm, and Health Trust, the ESOP firm, did not increase revenues, decrease operating expenses, or improve profitability after the LBOs, relative to other hospitals in their local markets. Nor were the numbers or salaries of employees at these facilities decreased. Although performance incentives associated with LBOs did not change performance at the hospital level, incentives to meet debt payments did result in corporate changes. More specifically, the LBOs led to corporate downsizing through the sale of hospitals and subsidiaries.

Adenosine diphosphate as an intracellular regulator of insulin secretion

Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels couple the cellular metabolic state to electrical activity and are a critical link between blood glucose concentration and pancreatic insulin secretion. A mutation in the second nucleotide-binding fold (NBF2) of the sulfonylurea receptor (SUR) of an individual diagnosed with persistent hyperinsulinemic hypoglycemia of infancy generated KATP channels that could be opened by diazoxide but not in response to metabolic inhibition. The hamster SUR, containing the analogous mutation, had normal ATP sensitivity, but unlike wild-type channels, inhibition by ATP was not antagonized by adenosine diphosphate (ADP). Additional mutations in NBF2 resulted in the same phenotype, whereas an equivalent mutation in NBF1 showed normal sensitivity to MgADP. Thus, by binding to SUR NBF2 and antagonizing ATP inhibition of KATP++ channels, intracellular MgADP may regulate insulin secretion.

A family of sulfonylurea receptors determines the pharmacological properties of ATP-sensitive K+ channels

We have cloned an isoform of the sulfonylurea receptor (SUR), designated SUR2. Coexpression of SUR2 and the inward rectifier K+ channel subunit Kir6.2 in COS1 cells reconstitutes the properties of K(ATP) channels described in cardiac and skeletal muscle. The SUR2/Kir6.2 channel is less sensitive than the SUR/Kir6.2 channel (the pancreatic beta cell KATP channel) to both ATP and the sulfonylurea glibenclamide and is activated by the cardiac K(ATP) channel openers, cromakalim and pinacidil, but not by diazoxide. In addition, SUR2 binds glibenclamide with lower affinity. The present study shows that the ATP sensitivity and pharmacological properties of K(ATP) channels are determined by a family of structurally related but functionally distinct sulfonylurea receptors.

Philanthropy and hospital financing

OBJECTIVE

This study explores the relationships among donations to not-for-profit hospitals, the returns provided by these hospitals, and fund-raising efforts. It tests a model of hospital behavior and addresses an earlier debate regarding the supply price of donations.

DATA SOURCES

The main data source is the California Office of Statewide Health Planning data tapes of hospital financial disclosure reports for fiscal years 1980/1981 through 1986/1987. Complete data were available for 160 hospitals.

STUDY DESIGN

Three structural equations (donations, returns, and fund-raising) are estimated as a system using a fixed-effects, pooled cross-section, time-series least squares regression.

PRINCIPAL FINDINGS

Estimation results reveal the expected positive relation between donations and returns. The reverse relation between returns and donations is insignificant. The estimated effect of fund-raising on donations is insignificantly different from zero, and the effect of donations on fund-raising is negative. Fund-raising and returns are negatively associated with one another.

CONCLUSION

The empirical results presented here suggest a positive donations-returns relations and are consistent with a positive supply price for donations. Hospitals appear to view a trade-off between providing returns and soliciting donations, but donors do not respond equally to these two activities. Attempts to increase free cash flow through expansion of community returns or fund-raising activity, at least in the short run, are not likely to be highly successful financing strategies for many hospitals.

Reconstitution of IKATP: an inward rectifier subunit plus the sulfonylurea receptor

A member of the inwardly rectifying potassium channel family was cloned here. The channel, called BIR (Kir6.2), was expressed in large amounts in rat pancreatic islets and glucose-responsive insulin-secreting cell lines. Coexpression with the sulfonylurea receptor SUR reconstituted an inwardly rectifying potassium conductance of 76 picosiemens that was sensitive to adenosine triphosphate (ATP) (IKATP) and was inhibited by sulfonylureas and activated by diazoxide. The data indicate that these pancreatic beta cell potassium channels are a complex composed of at least two subunits--BIR, a member of the inward rectifier potassium channel family, and SUR, a member of the ATP-binding cassette superfamily. Gene mapping data show that these two potassium channel subunit genes are clustered on human chromosome 11 at position 11p15.1.

Fundraising, government grants and donations to nonprofit hospital charities

Using 1982-1987 tax return data from California hospital charities, this paper investigates the relationship between fundraising expenditures, government grants and donations, during a time in which significant changes were being made in the system of hospital reimbursement. Empirical results suggest that while donations have been declining, charities have been efficient in their solicitation of donations. Results also suggest that government grants worked to reduce charitable contributions in the period before the institution of Medicare's Prospective Payment System. In more recent years, government grants have been associated with increases in donations to hospital charities.

Cloning of the beta cell high-affinity sulfonylurea receptor: a regulator of insulin secretion

Sulfonylureas are a class of drugs widely used to promote insulin secretion in the treatment of non-insulin-dependent diabetes mellitus. These drugs interact with the sulfonylurea receptor of pancreatic beta cells and inhibit the conductance of adenosine triphosphate (ATP)-dependent potassium (KATP) channels. Cloning of complementary DNAs for the high-affinity sulfonylurea receptor indicates that it is a member of the ATP-binding cassette or traffic ATPase superfamily with multiple membrane-spanning domains and two nucleotide binding folds. The results suggest that the sulfonylurea receptor may sense changes in ATP and ADP concentration, affect KATP channel activity, and thereby modulate insulin release.

Hantavirus infections in The Netherlands: epidemiology and disease

A serological survey for the prevalence of hantavirus infections in The Netherlands was carried out on > 10,000 sera, from selected human populations, and different feral and domestic animal species. Hantavirus-specific antibodies were found in about 1% of patients suspected of acute leptospirosis, 10% of patients with acute nephropathia, and in less than 0.1% haemodialysis and renal transplant patients. Among individuals with a suspected occupational risk, 6% of animal trappers, 4% of forestry workers, 2% of laboratory workers and 0.4% of farmers were seropositive. The majority of the seropositive individuals lived in rural and forested areas. The main animal reservoir of the infection was shown to be the red bank vole (Clethrionomys glareolus). Epidemiological, clinical and laboratory findings seen in serologically confirmed human cases were similar to those associated with nephropathia epidemica.

Class and subclass distribution of Hantavirus-specific serum antibodies at different times after the onset of nephropathia epidemica

Sera from Dutch and Belgium individuals who suffered from nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome (HFRS), were tested for the distribution of classes and subclasses of Hantavirus (HV)-specific antibodies at different times after the onset of the disease, with class- and subclass-specific Ig capture enzyme-linked immunosorbent assays (ELISAs). In the acute, early convalescent, and convalescent phases, predominantly specific IgA, IgM, and IgG3 antibodies were detected. Specific IgG2 antibodies were only detected at low levels in the early convalescent and convalescent phases. In the late convalescent phase specific IgG1 and IgG3 antibodies were found, whereas in the late postconvalescent phase only specific IgG1 antibodies proved to be present. Specific IgG4 antibodies were not detected in any of the respective phases. These data show that the simultaneous determination of classes and subclasses of HV specific serum antibodies allows the estimation of the time elapsed after the onset of NE.

Hospital corporate restructuring and financial performance

In the last decade, an important innovation in the organizational structure of acute care hospitals occurred. Many hospitals restructured by creating subsidiaries that segment assets or services into separate corporations. We know relatively little about the effects of such restructuring. This paper examines the association of restructuring with financial performance of not-for-profit hospital firms. The study uses data from all not-for-profit acute care hospital firms in Virginia, the only state for which the unique study data are available. We find that the consolidated financial performance of hospital firms is influenced by factors that affect the hospital's financial performance (i.e., payer-mix, staffing and service mix) but not the number or size of non-hospital subsidiaries. Future research should examine the effect of restructuring on other types of performance.