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The root causes of dementia are still largely unclear, and the medical community lacks highly effective preventive and therapeutic pharmaceutical agents for dementia despite large investments into their development. There is growing interest in the question if infectious agents play a role in the development of dementia, with herpesviruses attracting particular attention. To provide causal as opposed to merely correlational evidence on this question, we take advantage of the fact that in Wales eligibility for the herpes zoster vaccine (Zostavax) for shingles prevention was determined based on an individual’s exact date of birth. Those born before September 2 1933 were ineligible and remained ineligible for life, while those born on or after September 2 1933 were eligible to receive the vaccine. By using country-wide data on all vaccinations received, primary and secondary care encounters, death certificates, and patients’ date of birth in weeks, we first show that the percentage of adults who received the vaccine increased from 0.01% among patients who were merely one week too old to be eligible, to 47.2% among those who were just one week younger. Apart from this large difference in the probability of ever receiving the herpes zoster vaccine, there is no plausible reason why those born just one week prior to September 2 1933 should differ systematically from those born one week later. We demonstrate this empirically by showing that there were no systematic differences (e.g., in pre-existing conditions or uptake of other preventive interventions) between adults across the date-of-birth eligibility cutoff, and that there were no other interventions that used the exact same date-of-birth eligibility cutoff as was used for the herpes zoster vaccine program. This unique natural randomization, thus, allows for robust causal, rather than correlational, effect estimation. We first replicate the vaccine’s known effect from clinical trials of reducing the occurrence of shingles. We then show that receiving the herpes zoster vaccine reduced the probability of a new dementia diagnosis over a follow-up period of seven years by 3.5 percentage points (95% CI: 0.6 – 7.1, p=0.019), corresponding to a 19.9% relative reduction in the occurrence of dementia. Besides preventing shingles and dementia, the herpes zoster vaccine had no effects on any other common causes of morbidity and mortality. In exploratory analyses, we find that the protective effects from the vaccine for dementia are far stronger among women than men. Randomized trials are needed to determine the optimal population groups and time interval for administration of the herpes zoster vaccine to prevent or delay dementia, as well as to quantify the magnitude of the causal effect when more precise measures of cognition are used. Our findings strongly suggest an important role of the varicella zoster virus in the etiology of dementia.

The wake-active orexin system plays a central role in the dynamic regulation of glucose homeostasis. Here we show orexin receptor type 1 and 2 are predominantly expressed in dorsal raphe nucleus-dorsal and -ventral, respectively. Serotonergic neurons in ventral median raphe nucleus and raphe pallidus selectively express orexin receptor type 1. Inactivation of orexin receptor type 1 in serotonin transporter-expressing cells of mice reduced insulin sensitivity in diet-induced obesity, mainly by decreasing glucose utilization in brown adipose tissue and skeletal muscle. Selective inactivation of orexin receptor type 2 improved glucose tolerance and insulin sensitivity in obese mice, mainly through a decrease in hepatic gluconeogenesis. Optogenetic activation of orexin neurons in lateral hypothalamus or orexinergic fibers innervating raphe pallidus impaired or improved glucose tolerance, respectively. Collectively, the present study assigns orexin signaling in serotonergic neurons critical, yet differential orexin receptor type 1- and 2-dependent functions in the regulation of systemic glucose homeostasis., The wake-active orexin system plays a central role in the dynamic regulation of glucose homeostasis. Here the authors report that inactivation of the orexin receptor type 1 or 2 in serotonergic neurons differentially regulate systemic glucose homeostasis in the context of diet induced obesity.

This article investigates the effects of development projects on economic networks. To this end, we study the impact that a randomly allocated Community-Driven Development program in The Gambia has on economic interactions within rural villages. The program provides an exogenous source of variation to village-level stocks of productive capital and to village-wide collective activities. Based on detailed data on economic and social networks, we find a significant reduction of transfers in these networks in treatment villages. Guided by a theoretical framework, we investigate several possible mechanisms and find evidence that is consistent with two channels. First, the evidence points to modest wealth effects and a village-level transformation process towards a more formal economy. Second, we also find evidence that is consistent with elite capture, favouritism, and unequally distributed benefits leading to reductions in social capital and thus economic transactions. Overall, our findings suggest changes in networks as an avenue through which development interventions may have unintended consequences.

The maternal perinatal environment modulates brain formation, and altered maternal nutrition has been linked to the development of metabolic and psychiatric disorders in the offspring. Here, we showed that maternal high-fat diet (HFD) feeding during lactation in mice elicits long-lasting changes in gene expression in the offspring’s dopaminergic circuitry. This translated into silencing of dopaminergic midbrain neurons, reduced connectivity to their downstream targets, and reduced stimulus-evoked dopamine (DA) release in the striatum. Despite the attenuated activity of DA midbrain neurons, offspring from mothers exposed to HFD feeding exhibited a sexually dimorphic expression of DA-related phenotypes, i.e., hyperlocomotion in males and increased intake of palatable food and sucrose in females. These phenotypes arose from concomitantly increased spontaneous activity of D1 medium spiny neurons (MSNs) and profoundly decreased D2 MSN projections. Overall, we have unraveled a fundamental restructuring of dopaminergic circuitries upon time-restricted altered maternal nutrition to induce persistent behavioral changes in the offspring.

Graphical abstract How to get error bars on the ratiometric calcium estimator? The two measurements areas (region of interest, ROI, on the cell body and background measurement region, BMR, outside of the cell) are displayed on the frame corresponding to one actual experiment. Two measurements, one following an excitation at 340 nm and the other following an excitation at 380 nm are performed (at each ’time point’) from each region. The result is a set of four measures: adu340 (from the ROI), adu340,B (from the BMR), adu380 and adu380,B.. The fact that the measurements as well as the subsequent quantities derived from them are random variable realization is conveyed throughout the figure by the use of Gaussian probability densities. The densities from the BMR are ’tighter’ because there are much more pixels in the BMR than in the ROI (the standard deviations of the densities shown on this figure have been enlarged for clarity, but their relative size has been preserved, the horizontal axis in black always starts at 0). The key result of the paper is that the standard deviation of the four Gaussian densities corresponding to the raw data (bottom of the figure) can be reliably estimated from the data alone, egσ380≈Gadu380+V, where V is the product of the CCD chip gain squared by the number of pixels in the ROI by the CCD chip read-out variance. The paper explains how to compute the standard deviation of the derived distributions obtained at each step of the calcium concentration estimation., The ratiometric fluorescent calcium indicator Fura-2 plays a fundamental role in the investigation of cellular calcium dynamics. Despite of its widespread use in the last 30 years, only one publication (Joucla et al., 2010)) proposed a way of obtaining confidence intervals on fitted calcium dynamic model parameters from single ‘calcium transients’. Shortcomings of this approach are its requirement for a ‘3 wavelengths’ protocol (excitation at 340 and 380 nm as usual plus at 360 nm, the isosbestic point) as well as the need for an autofluorence / background fluorescence model at each wavelength. Here, we propose a simpler method that eliminates both shortcommings:1.a precise estimation of the standard errors of the raw data is obtained first,2.the standard error of the ratiometric calcium estimator (a function of the raw data values) is derived using both the propagation of uncertainty and a Monte-Carlo method.Once meaningful standard errors for calcium estimates are available, standard errors on fitted model parameters follow directly from the use of nonlinear least-squares optimization algorithms.

In dopaminergic (DA)

In dopaminergic (DA) substantia nigra (SN) neurons Cav2.3 R-type Ca2+-currents contribute to somatodendritic Ca2+-oscillations. These may contribute to the selective degeneration of these neurons in Parkinson’s disease (PD) since Cav2.3-knockout is neuroprotective in a PD mouse model. However, the typical Cav2.3 gating would predict complete channel inactivation during SN DA neuronal firing. Here we show that in tsA-201-cells the membrane-anchored β2-splice variants β2a and β2e stabilize Cav2.3 gating properties allowing sustained Cav2.3 availability during simulated pacemaking and enhanced Ca2+-currents during bursts. We confirmed the expression of β2a and β2e-subunits in the SN and identified SN DA neurons. Patch-clamp recordings of SN DA neurons in mouse brain slices revealed R-type Ca2+-currents similar to β2a- or β2e-stabilized Cav2.3-currents and recordings in cultured murine DA neurons confirmed their activity during pacemaking. Taken together, our data support an important (patho)physiological role of β-subunit alternative splicing for Cav2.3 Ca2+-signaling in highly vulnerable SN DA neurons.

Ca2+functions as an important intracellular signal for a wide range of cellular processes. These processes are selectively activated by controlled spatiotemporal dynamics of the free cytosolic Ca2+. Intracellular Ca2+dynamics are regulated by numerous cellular parameters. Here, we established a new way to determine neuronal Ca2+handling properties by combining the ‘added buffer’ approach (Neher and Augustine, 1992) with perforated patch-clamp recordings (Horn and Marty, 1988). Since the added buffer approach typically employs the standard whole-cell configuration for concentration-controlled Ca2+indicator loading, it only allows for the reliable estimation of the immobile fraction of intracellular Ca2+buffers. Furthermore, crucial components of intracellular signaling pathways are being washed out during prolonged whole-cell recordings, leading to cellular deterioration. By combining the added buffer approach with perforated patch-clamp recordings, these issues are circumvented, allowing the precise quantification of the cellular Ca2+handling properties, including immobile as well as mobile Ca2+buffers.

SUMMARY Anorexigenic pro-opiomelanocortin (Pomc)/alpha-melanocyte stimulating hormone (αMSH) neurons of the hypothalamic melanocortin system function as key regulators of energy homeostasis, also controlling somatic growth across different species. However, the mechanisms of melanocortin-dependent growth control still remain ill-defined. Here, we reveal a thus-far-unrecognized structural and functional connection between Pomc neurons and the somatotropic hypothalamo-pituitary axis. Excessive feeding of larval zebrafish causes leptin resistance and reduced levels of the hypothalamic satiety mediator pomca. In turn, this leads to reduced activation of hypophysiotropic somatostatin (Sst)-neurons that express the melanocortin receptor Mc4r, elevated growth hormone (GH) expression in the pituitary, and enhanced somatic growth. Mc4r expression and αMSH responsiveness are conserved in Sst-expressing hypothalamic neurons of mice. Thus, acquired leptin resistance and attenuation of pomca transcription in response to excessive caloric intake may represent an ancient mechanism to promote somatic growth when food resources are plentiful., Graphical abstract In Brief: The melanocortin system controls energy homeostasis and somatic growth, but the underlying mechanisms are elusive. Löhr et al. identify a functional neural circuit in which Pomc neurons stimulate hypothalamic somatostatin neurons, thereby inhibiting hypophyseal growth hormone production. Excessive feeding and acquired leptin resistance attenuate this pathway, allowing faster somatic growth when food resources are rich.

International audience; Ca 2+ functions as an important intracellular signal for a wide range of cellular processes. These processes are selectively activated by controlled spatiotemporal dynamics of the free cytosolic Ca 2+ . Intracellular Ca 2+ dynamics are regulated by numerous cellular parameters. Here, we established a new way to determine neuronal Ca 2+ handling properties by combining the ‘added buffer’ approach (Neher and Augustine, 1992) with perforated patch-clamp recordings (Horn and Marty, 1988). Since the added buffer approach typically employs the standard whole-cell configuration for concentration-controlled Ca 2+ indicator loading, it only allows for the reliable estimation of the immobile fraction of intracellular Ca 2+ buffers. Furthermore, crucial components of intracellular signaling pathways are being washed out during prolonged whole-cell recordings, leading to cellular deterioration. By combining the added buffer approach with perforated patch-clamp recordings, these issues are circumvented, allowing the precise quantification of the cellular Ca 2+ handling properties, including immobile as well as mobile Ca 2+ buffers.

Randomization inference or permutation tests are only sporadically used in economics and other social sciences—this despite a steep increase in randomization in field and laboratory experiments that provide perfect experimental setups for applying randomization inference. In the context of causal inference, such tests can handle problems often faced by applied researchers, including issues arising in the context of small samples, stratified or clustered treatment assignments, or nonstandard randomization techniques. Standard statistical software packages have either no implementation of randomization tests or very basic implementations. Whenever researchers use randomization inference, they regularly code individual program routines, risking inconsistencies and coding mistakes. In this article, I show how randomization inference can best be conducted in Stata and introduce a new command, ritest, to simplify such analyses. I illustrate this approach's usefulness by replicating the results in Fujiwara and Wantchekon (2013, American Economic Journal: Applied Economics 5: 241–255) and running simulations. The applications cover clustered and stratified assignments, with varying cluster sizes, pairwise randomization, and the computation of nonapproximate p-values. The applications also touch upon joint hypothesis testing with randomization inference.

Ca(2+)-influx through L-type Ca(2+)-channels (LTCCs) is associated with activity-related stressful oscillations of Ca(2+) levels within dopaminergic (DA) neurons in the substantia nigra (SN), which may contribute to their selective degeneration in Parkinson's disease (PD). LTCC blockers were neuroprotective in mouse neurotoxin models of PD, and isradipine is currently undergoing testing in a phase III clinical trial in early PD. We report no evidence for neuroprotection by in vivo pretreatment with therapeutically relevant isradipine plasma levels, or Ca(v)1.3 LTCC deficiency in 6-OHDA-treated male mice. To explain this finding, we investigated the pharmacological properties of human LTCCs during SN DA-like and arterial smooth muscle (aSM)-like activity patterns using whole-cell patch-clamp recordings in HEK293 cells (Ca(v)1.2 α1-subunit, long and short Ca(v)1.3 α1-subunit splice variants; β3/α2δ1). During SN DA-like pacemaking, only Ca(v)1.3 variants conducted Ca(2+) current (I(Ca)) at subthreshold potentials between action potentials. SN DA-like burst activity increased integrated I(Ca) during (Ca(v)1.2 plus Ca(v)1.3) and after (Ca(v)1.3) the burst. Isradipine inhibition was splice variant and isoform dependent, with a 5- to 11-fold lower sensitivity to Ca(v)1.3 variants during SN DA-like pacemaking compared with Ca(v)1.2 during aSM-like activity. Supratherapeutic isradipine concentrations reduced the pacemaker precision of adult mouse SN DA neurons but did not affect their somatic Ca(2+) oscillations. Our data predict that Ca(v)1.2 and Ca(v)1.3 splice variants contribute differentially to Ca(2+) load in SN DA neurons, with prominent Ca(v)1.3-mediated I(Ca) between action potentials and after bursts. The failure of therapeutically relevant isradipine levels to protect SN DA neurons can be explained by weaker state-dependent inhibition of SN DA LTCCs compared with aSM Ca(v)1.2. SIGNIFICANCE STATEMENT The high vulnerability of dopamine (DA) neurons in the substantia nigra (SN) to neurodegenerative stressors causes Parkinson's disease (PD). Ca(2+) influx through voltage-gated L-type Ca(2+) channels (LTCCs), in particular Ca(v)1.3, appears to contribute to this vulnerability, and the LTCC inhibitor isradipine is currently being tested as a neuroprotective agent for PD in a phase III clinical trial. However, in our study isradipine plasma concentrations approved for therapy were not neuroprotective in a PD mouse model. We provide an explanation for this observation by demonstrating that during SN DA-like neuronal activity LTCCs are less sensitive to isradipine than Ca(v)1.2 LTCCs in resistance blood vessels (mediating dose-limiting vasodilating effects) and even at supratherapeutic concentrations isradipine fails to reduce somatic Ca(2+) oscillations of SN DA neurons.

Mitochondrial dysfunction causes neurodegeneration but whether impairment of mitochondrial homeostasis in astrocytes contributes to this pathological process remains largely unknown. The m‐AAA protease exerts quality control and regulatory functions crucial for mitochondrial homeostasis. AFG3L2, which encodes one of the subunits of the m‐AAA protease, is mutated in spinocerebellar ataxia SCA28 and in infantile syndromes characterized by spastic‐ataxia, epilepsy and premature death. Here, we investigate the role of Afg3l2 and its redundant homologue Afg3l1 in the Bergmann glia (BG), radial astrocytes of the cerebellum that have functional connections with Purkinje cells (PC) and regulate glutamate homeostasis. We show that astrocyte‐specific deletion of Afg3l2 in the mouse leads to late‐onset motor impairment and to degeneration of BG, which display aberrant morphology, altered expression of the glutamate transporter EAAT2, and a reactive inflammatory signature. The neurological and glial phenotypes are drastically exacerbated when astrocytes lack both Afg31l and Afg3l2, and therefore, are totally depleted of the m‐AAA protease. Moreover, mitochondrial stress responses and necroptotic markers are induced in the cerebellum. In both mouse models, targeted BG show a fragmented mitochondrial network and loss of mitochondrial cristae, but no signs of respiratory dysfunction. Importantly, astrocyte‐specific deficiency of Afg3l1 and Afg3l2 triggers secondary morphological degeneration and electrophysiological changes in PCs, thus demonstrating a non‐cell‐autonomous role of glia in neurodegeneration. We propose that astrocyte dysfunction amplifies both neuroinflammation and glutamate excitotoxicity in patients carrying mutations in AFG3L2, leading to a vicious circle that contributes to neuronal death.

Accumulation of mitochondrial DNA deletions is observed especially in dopaminergic neurons of the substantia nigra during ageing and even more in Parkinson's disease. The resulting mitochondrial dysfunction is suspected to play an important role in neurodegeneration. However, the molecular mechanisms involved in the preferential generation of mitochondrial DNA deletions in dopaminergic neurons are still unknown. To study this phenomenon, we developed novel polymerase chain reaction strategies to detect distinct mitochondrial DNA deletions and monitor their accumulation patterns. Applying these approaches in in vitro and in vivo models, we show that catecholamine metabolism drives the generation and accumulation of these mitochondrial DNA mutations. As in humans, age-related accumulation of mitochondrial DNA deletions is most prominent in dopaminergic areas of mouse brain and even higher in the catecholaminergic adrenal medulla. Dopamine treatment of terminally differentiated neuroblastoma cells, as well as stimulation of dopamine turnover in mice over-expressing monoamine oxidase B both induce multiple mitochondrial DNA deletions. Our results thus identify catecholamine metabolism as the driving force behind mitochondrial DNA deletions, probably being an important factor in the ageing-associated degeneration of dopaminergic neurons.

Summary Brown adipose tissue (BAT) is a critical regulator of glucose, lipid, and energy homeostasis, and its activity is tightly controlled by the sympathetic nervous system. However, the mechanisms underlying CNS-dependent control of BAT sympathetic nerve activity (SNA) are only partly understood. Here, we demonstrate that catecholaminergic neurons in the locus coeruleus (LC) adapt their firing frequency to extracellular glucose concentrations in a K ATP -channel-dependent manner. Inhibiting K ATP -channel-dependent control of neuronal activity via the expression of a variant K ATP channel in tyrosine-hydroxylase-expressing neurons and in neurons of the LC enhances diet-induced obesity in mice. Obesity results from decreased energy expenditure, lower steady-state BAT SNA, and an attenuated ability of centrally applied glucose to activate BAT SNA. This impairs the thermogenic transcriptional program of BAT. Collectively, our data reveal a role of K ATP -channel-dependent neuronal excitability in catecholaminergic neurons in maintaining thermogenic BAT sympathetic tone and energy homeostasis.

Melanin-concentrating-hormone (MCH)-expressing neurons (MCH neurons) in the lateral hypothalamus (LH) are critical regulators of energy and glucose homeostasis. Here, we demonstrate that insulin increases the excitability of these neurons in control mice. In vivo, insulin promotes phosphatidylinositol 3-kinase (PI3K) signaling in MCH neurons, and cell-type-specific deletion of the insulin receptor (IR) abrogates this response. While lean mice lacking the IR in MCH neurons (IRΔMCH) exhibit no detectable metabolic phenotype under normal diet feeding, they present with improved locomotor activity and insulin sensitivity under high-fat-diet-fed, obese conditions. Similarly, obesity promotes PI3 kinase signaling in these neurons, and this response is abrogated in IRΔMCH mice. In turn, acute chemogenetic activation of MCH neurons impairs locomotor activity but not insulin sensitivity. Collectively, our experiments reveal an insulin-dependent activation of MCH neurons in obesity, which contributes via distinct mechanisms to the manifestation of impaired locomotor activity and insulin resistance.

Steroidogenic factor 1 (SF-1)-expressing neurons of the ventromedial hypothalamus (VMH) control energy homeostasis, but the role of insulin action in these cells remains undefined. We show that insulin activates phosphatidylinositol-3-OH kinase (PI3K) signaling in SF-1 neurons and reduces firing frequency in these cells through activation of K(ATP) channels. These effects were abrogated in mice with insulin receptor deficiency restricted to SF-1 neurons (SF-1(ΔIR) mice). Whereas body weight and glucose homeostasis remained the same in SF-1(ΔIR) mice as in controls under a normal chow diet, they were protected from diet-induced leptin resistance, weight gain, adiposity and impaired glucose tolerance. High-fat feeding activated PI3K signaling in SF-1 neurons of control mice, and this response was attenuated in the VMH of SF-1(ΔIR) mice. Mimicking diet-induced overactivation of PI3K signaling by disruption of the phosphatidylinositol-3,4,5-trisphosphate phosphatase PTEN led to increased body weight and hyperphagia under a normal chow diet. Collectively, our experiments reveal that high-fat diet-induced, insulin-dependent PI3K activation in VMH neurons contributes to obesity development.

Dopaminergic midbrain neurons integrate signals on food palatability and food-associated reward into the complex control of energy homeostasis. To define the role of insulin receptor (IR) signaling in this circuitry, we inactivated IR signaling in tyrosine hydroxylase (Th)-expressing cells of mice (IR(DeltaTh)). IR inactivation in Th-expressing cells of mice resulted in increased body weight, increased fat mass, and hyperphagia. While insulin acutely stimulated firing frequency in 50% of dopaminergic VTA/SN neurons, this response was abolished in IR(DeltaTh) mice. Moreover, these mice exhibited an altered response to cocaine under food-restricted conditions. Taken together, these data provide in vivo evidence for a critical role of insulin signaling in catecholaminergic neurons to control food intake and energy homeostasis.

Leptin-stimulated Stat3 activation in proopiomelanocortin (POMC)-expressing neurons of the hypothalamus plays an important role in maintenance of energy homeostasis. While Stat3 activation in POMC neurons is required for POMC expression, the role of elevated basal Stat3 activation as present in the development of obesity has not been directly addressed. Here, we have generated and characterized mice expressing a constitutively active version of Stat3 (Stat3-C) in POMC neurons (Stat3-CPOMCmice). On normal chow diet, these animals develop obesity as a result of hyperphagia and decreased POMC expression accompanied by central leptin and insulin resistance. This unexpected finding coincides with POMC-cell-specific, Stat3-mediated upregulation of SOCS3 expression inhibiting both leptin and insulin signaling as insulin-stimulated PIP3(phosphatidylinositol-3,4,5 triphosphate) formation and protein kinase B (AKT) activation in POMC neurons as well as with the fact that insulin's ability to hyperpolarize POMC neurons is largely reduced in POMC cells of Stat3-CPOMCmice. These data indicate that constitutive Stat3 activation is not sufficient to promote POMC expression but requires simultaneous PI3K (phosphoinositide 3-kinase)-dependent release of FOXO1 repression. In contrast, upon exposure to a high-fat diet, food intake and body weight were unaltered in Stat3-CPOMCmice compared with control mice. Taken together, these experiments directly demonstrate that enhanced basal Stat3 activation in POMC neurons as present in control mice upon high-fat feeding contributes to the development of hypothalamic leptin and insulin resistance.

SummaryMaternal metabolic homeostasis exerts long-term effects on the offspring’s health outcomes. Here, we demonstrate that maternal high-fat diet (HFD) feeding during lactation predisposes the offspring for obesity and impaired glucose homeostasis in mice, which is associated with an impairment of the hypothalamic melanocortin circuitry. Whereas the number and neuropeptide expression of anorexigenic proopiomelanocortin (POMC) and orexigenic agouti-related peptide (AgRP) neurons, electrophysiological properties of POMC neurons, and posttranslational processing of POMC remain unaffected in response to maternal HFD feeding during lactation, the formation of POMC and AgRP projections to hypothalamic target sites is severely impaired. Abrogating insulin action in POMC neurons of the offspring prevents altered POMC projections to the preautonomic paraventricular nucleus of the hypothalamus (PVH), pancreatic parasympathetic innervation, and impaired glucose-stimulated insulin secretion in response to maternal overnutrition. These experiments reveal a critical timing, when altered maternal metabolism disrupts metabolic homeostasis in the offspring via impairing neuronal projections, and show that abnormal insulin signaling contributes to this effect.

Dopaminergic (DA) signaling governs the control of complex behaviors, and its deregulation has been implicated in a wide range of diseases. Here we demonstrate that inactivation of the Fto gene, encoding a nucleic acid demethylase, impairs dopamine receptor type 2 (D2R) and type 3 (D3R) (collectively, 'D2-like receptor')-dependent control of neuronal activity and behavioral responses. Conventional and DA neuron-specific Fto knockout mice show attenuated activation of G protein-coupled inwardly-rectifying potassium (GIRK) channel conductance by cocaine and quinpirole. Impaired D2-like receptor-mediated autoinhibition results in attenuated quinpirole-mediated reduction of locomotion and an enhanced sensitivity to the locomotor- and reward-stimulatory actions of cocaine. Analysis of global N(6)-methyladenosine (m(6)A) modification of mRNAs using methylated RNA immunoprecipitation coupled with next-generation sequencing in the midbrain and striatum of Fto-deficient mice revealed increased adenosine methylation in a subset of mRNAs important for neuronal signaling, including many in the DA signaling pathway. Several proteins encoded by these mRNAs had altered expression levels. Collectively, FTO regulates the demethylation of specific mRNAs in vivo, and this activity relates to the control of DA transmission.

Coronin proteins belong to the super family of eukaryotic-specific WD40-repeat domain proteins.1 Phylogenetic analyses of the coronin family of proteins defined 17 coronin subfamilies, including 7 paralogs in mammals.2–4 CRN2 is a 474 amino acid short coronin5 harboring 7 WD40-repeats, which adopt the fold of a 7-bladed β-propeller.6,7 It has an apparent molecular mass of 57 kDa (reference sequences: {"type":"entrez-nucleotide","attrs":{"text":"NM_014325.2","term_id":"27477119","term_text":"NM_014325.2"}}NM_014325.2, {"type":"entrez-protein","attrs":{"text":"NP_055140.1","term_id":"7656991","term_text":"NP_055140.1"}}NP_055140.1). Coronin proteins function in cellular actin dynamics and play important roles in numerous cellular processes, for example, in secretion, matrix degradation, protrusion formation, cell migration, and invasion.8 CRN2 homo-trimerizes via its C-terminal coiled coil domain and binds to and bundles actin filaments via 3 actin binding sites.9–12 CRN2's F-actin bundling activity and inhibitory effect on actin polymerization are abolished by CK2-dependent phosphorylation of CRN2 at serine 463, as shown by in vitro and in vivo kinase assays and the use of S463D phospho-mimetic and S463A phospho-resistant CRN2 variants.12 In addition, CRN2 regulates the actin cytoskeleton via interaction with small G-proteins. An interaction of CRN2 with GDP-Rab27a increased its F-actin bundling activity and endocytosis of the insulin secretory membrane in pancreatic beta cells.4,13 With respect to human cancer, the number of CRN2 positive tumor cells is correlated with the malignant phenotype of human diffuse gliomas. Gliomas of high grade, such as anaplastic astrocytomas, anaplastic oligodendrogliomas, anaplastic oligoastrocytomas, and glioblastomas, show high numbers of CRN2-positive tumor cells, whereas low-grade gliomas, such as diffuse astrocytomas, oligodendrogliomas, and oligoastrocytomas, show low numbers of CRN2-positive tumor cells.14 Furthermore, CRN2 expression is up-regulated in melanoma cells.15 In another study, the expression level of CRN2 correlated with the clinical progression of hepatocellular carcinoma.16 Finally, the CRN2 gene was amplified in one-fourth and the CRN2 expression was elevated in three-fourths of the specimens of primary effusion lymphoma.17 In the present work, we show that increased expression of CRN2 or presence of the S463A phospho-resistant mutant promote glioblastoma cell invasion in vitro and tumor growth ex vivo, whereas knock-down of CRN2 or expression of the S463D phospho-mimetic variant causes opposite effects.

In many mammals, body weight increases continuously throughout adulthood until late middle age. The hormone leptin is necessary for maintaining body weight, in that high levels of leptin promote negative energy balance. As animals age, however, their increase in body weight is accompanied by a steady rise in circulating leptin levels, indicating the progressive development of counterregulatory mechanisms to antagonize leptin's anorexigenic effects. Hypothalamic neurons coexpressing agouti-related peptide (AgRP) and neuropeptide Y are direct leptin targets. These neurons promote positive energy balance, and they inhibit anorexigenic proopiomelanocortin (POMC) neurons via direct neuropeptide action and release of γ-aminobutyric acid. We show here that AgRP and neuropeptide Y innvervation onto POMC neurons increases dramatically with age in male mice. This is associated with progressive increase of inhibitory postsynaptic currents and decrease of POMC firing rate with age. Neuronal activity is significantly attenuated in POMC neurons that receive a high density of AgRP puncta. These high-density AgRP inputs correlate with leptin levels in normal mice and are nearly absent in mice lacking leptin. The progression of increased AgRP innervation onto POMC somas is accelerated in hyperleptinemic, diet-induced obese mice. Together our study suggests that modulation of hypothalamic AgRP innervation constitutes one mechanism to counter the effects of the age-associated rise in leptin levels, thus sustaining body weight and fat mass at an elevated level in adulthood.

The global economic crisis has seen global growth plummet to its lowest rate in 60 years against the backdrop of falling demand, declining manufacturing and industrial output, trade credit fi nancing problems and plunging consumer confi dence. The article argues that despite initial suggestions that the African continent, including the SADC region, would be insulated from the worst effects of the global economic crisis, the secondary, real economy impact of the crisis has been felt across the SADC countries. The article shows that the crisis has hit key drivers of growth, particularly trade and capital infl ows, across the region and has been felt principally through the SADC countries’ external accounts, trade balances, as well as access to capital fl ows and

Toward our goal to better understand the physiological parameters that mediate olfactory information processing on the cellular level, voltage-activated calcium currents ( ICa) in olfactory interneurons of the antennal lobe from adult cockroaches were analyzed under two conditions: 1) in acutely dissociated cells (in vitro) and 2) in an intact brain preparation (in situ). The study included an analysis of modulatory effects of potential inorganic and organic Ca2+channel blockers. ICawas isolated and identified using pharmacological, voltage, and ion substitution protocols. ICaconsisted of two components: transient and sustained. The decay of the transient component was largely Ca2+dependent. In vitro, ICahad an activation threshold of −50 mV with a maximal peak current at −7 mV and a half-maximal voltage ( V0.5act) for tail-current activation of −18 mV. In situ these parameters were significantly shifted to more depolarized membrane potentials: ICaactivated at −40 mV with a maximal peak current at 8 mV and a V0.5actfor tail-current activation of −11 mV. The sensitivity of ICato the divalent cations Cd2+, Co2+, and Ni2+was dose dependent. The most effective blocker was Cd2+with an IC50of 10−5M followed by Ni2+(IC50= 3.13 × 10−3M) and Co2+(IC50= 1.06 × 10−3M). The organic channel blockers verapamil, diltiazem, and nifedipine also blocked ICain a dose-dependent way and had differential effects on the current waveform. Verapamil blocked ICawith an IC50of 1.5 × 10−4M and diltiazem had an IC50of 2.87 × 10−4M. Nifedipine blocked ICaby 33% at a concentration of 10−4M.

The squid giant synapse was used to test the hypothesis that guanosine-5'-triphosphate (GTP)-binding proteins regulate the local distribution of synaptic vesicles within nerve terminals. Presynaptic injection of the nonhydrolyzable GTP analog GTP gamma S irreversibly inhibited neurotransmitter release without changing either the size of the calcium signals produced by presynaptic action potentials or the number of synaptic vesicles docked at presynaptic active zones. Neurotransmitter release was also inhibited by injection of the nonhydrolyzable guanosine diphosphate (GDP) analog GDP beta S but not by injection of AIF4-. These results suggest that a small molecular weight GTP-binding protein directs the docking of synaptic vesicles that occurs before calcium-dependent neurotransmitter release. Depletion of undocked synaptic vesicles by GTP gamma S indicates that additional GTP-binding proteins function in the terminal at other steps responsible for synaptic vesicle replenishment.

Obesity is an increasing health problem in the modern world. Feeding behavior is mostly controlled by homeostatic and hedonic systems. It was already demonstrated in the hypothalamus that diet-induced obesity can change the spontaneous activity of cells involved in homeostatic regulation. It is, however, unclear if the hedonic regulation is also affected by diet-induced obersity. The midbrain dopaminergic (DA) neurons are a key component of the hedonic system. Usually, dopaminergic neurons in brain slice preparations show a highly regular pacemaker-like activity pattern. However it was found in [1], that in mice fed on high fat diet (HFD) a significantly increased proportion of DA neurons fired irregularly as compared to the ones in mice that ware fed on normal diet (NCD). A mathematical model of midbrain dopaminergic neuron (DA) has been developed to better understand the mechanisms underlying the different types of firing patterns that these cells exhibit in vitro. The dopaminergic neuron was modeled using a single compartment which includes voltage and Ca2+-dependent currents described by Hodgkin-Huxley kinetics. The model used in this study is based on an existing DA neuron model [2,3] and some parameters were determined using new voltage-clamp data from HFD and NCD mouse brain slices.