CNTN6 mutations are risk factors for abnormal auditory sensory perception in autism spectrum disorders.

Contactin genes CNTN5 and CNTN6 code for neuronal cell adhesion molecules that promote neurite outgrowth in sensory-motor neuronal pathways. Mutations of CNTN5 and CNTN6 have previously been reported in individuals with autism spectrum disorders (ASDs), but very little is known on their prevalence and clinical impact. In this study, we identified CNTN5 and CNTN6 deleterious variants in individuals with ASD. Among the carriers, a girl with ASD and attention-deficit/hyperactivity disorder was carrying five copies of CNTN5. For CNTN6, both deletions (6/1534 ASD vs 1/8936 controls; P=0.00006) and private coding sequence variants (18/501 ASD vs 535/33480 controls; P=0.0005) were enriched in individuals with ASD. Among the rare CNTN6 variants, two deletions were transmitted by fathers diagnosed with ASD, one stop mutation CNTN6W923X was transmitted by a mother to her two sons with ASD and one variant CNTN6P770L was found de novo in a boy with ASD. Clinical investigations of the patients carrying CNTN5 or CNTN6 variants showed that they were hypersensitive to sounds (a condition called hyperacusis) and displayed changes in wave latency within the auditory pathway. These results reinforce the hypothesis of abnormal neuronal connectivity in the pathophysiology of ASD and shed new light on the genes that increase risk for abnormal sensory perception in ASD.

Electrical stimulation alleviates depressive-like behaviors of rats: investigation of brain targets and potential mechanisms.

Deep brain stimulation (DBS) is a promising therapy for patients with refractory depression. However, key questions remain with regard to which brain target(s) should be used for stimulation, and which mechanisms underlie the therapeutic effects. Here, we investigated the effect of DBS, with low- and high-frequency stimulation (LFS, HFS), in different brain regions (ventromedial prefrontal cortex, vmPFC; cingulate cortex, Cg; nucleus accumbens (NAc) core or shell; lateral habenula, LHb; and ventral tegmental area) on a variety of depressive-like behaviors using rat models. In the naive animal study, we found that HFS of the Cg, vmPFC, NAc core and LHb reduced anxiety levels and increased motivation for food. In the chronic unpredictable stress model, there was a robust depressive-like behavioral phenotype. Moreover, vmPFC HFS, in a comparison of all stimulated targets, produced the most profound antidepressant effects with enhanced hedonia, reduced anxiety and decreased forced-swim immobility. In the following set of electrophysiological and histochemical experiments designed to unravel some of the underlying mechanisms, we found that vmPFC HFS evoked a specific modulation of the serotonergic neurons in the dorsal raphe nucleus (DRN), which have long been linked to mood. Finally, using a neuronal mapping approach by means of c-Fos expression, we found that vmPFC HFS modulated a brain circuit linked to the DRN and known to be involved in affect. In conclusion, HFS of the vmPFC produced the most potent antidepressant effects in naive rats and rats subjected to stress by mechanisms also including the DRN.

[Autism spectrum disorder and suicidality]. / Troubles du spectre autistique et suicidalité.

INTRODUCTION: Most studies on suicide exclude subjects with autism spectrum disorders, yet there is a risk group. The purpose of this article is to present the data in the literature regarding the clinical and epidemiological characteristics of suicidality in subjects with autism spectrum disorders and to identify the factors that promote the transition to action. METHODS: This review was carried out using the data set collected in Medline PubMed, items with "autism spectrum disorder", "pervasive developmental disorder", "Asperger's syndrome", "suicide", "suicide attempt", and "suicide behavior". RESULTS: In all subjects from our research on PubMed, 21.3% of subjects with autism spectrum disorder reported suicidal ideation, have attempted suicide or died by suicide (115 out of 539 subjects) and 7.7% of subjects supported for suicidal thoughts or attempted suicide exhibited an autism spectrum disorder (62 out of 806 subjects), all ages combined. Suicidal ideation and morbid preoccupation are particularly common in adolescents and young adults. Suicide attempts are accompanied by a willingness for death and can lead to suicide. They are more common in high-functioning autism and Asperger subjects. The methods used are often violent and potentially lethal or fatal in two cases published. Suicide risk depends on many factors that highlight the vulnerability of these subjects, following autistic and developmental symptoms. Vulnerability complicating the diagnosis of comorbid depressive and anxiety disorders are major factors associated with suicidality. Vulnerability but also directly related to suicidality, since the origin of physical and sexual abuse and victimization by peers assigning them the role of "scapegoat" are both responsible for acting out. CONCLUSION: Given the diversity of factors involved in the risk of suicide in this population, this does not validate "a" program of intervention, but the intervention of "customized programs". Their implementation should be as early as possible in order to treat while the brain has the greatest plasticity. The aim is to provide the necessary access to the greatest possible autonomy. Hence, including working communication skills and interaction, these subject will have independent means of protection, an essential complement to measures to protect vulnerable subjects; the vulnerability of direct and indirect suicidality. Comorbid diagnoses must take into account the specificities of these patients, their difficulties in communicating their mental state, and adapted and innovative therapeutic strategies must be offered and validated.

Genomic architecture of human neuroanatomical diversity.

Human brain anatomy is strikingly diverse and highly inheritable: genetic factors may explain up to 80% of its variability. Prior studies have tried to detect genetic variants with a large effect on neuroanatomical diversity, but those currently identified account for <5% of the variance. Here, based on our analyses of neuroimaging and whole-genome genotyping data from 1765 subjects, we show that up to 54% of this heritability is captured by large numbers of single-nucleotide polymorphisms of small-effect spread throughout the genome, especially within genes and close regulatory regions. The genetic bases of neuroanatomical diversity appear to be relatively independent of those of body size (height), but shared with those of verbal intelligence scores. The study of this genomic architecture should help us better understand brain evolution and disease.

Cntnap4 differentially contributes to GABAergic and dopaminergic synaptic transmission.

Although considerable evidence suggests that the chemical synapse is a lynchpin underlying affective disorders, how molecular insults differentially affect specific synaptic connections remains poorly understood. For instance, Neurexin 1a and 2 (NRXN1 and NRXN2) and CNTNAP2 (also known as CASPR2), all members of the neurexin superfamily of transmembrane molecules, have been implicated in neuropsychiatric disorders. However, their loss leads to deficits that have been best characterized with regard to their effect on excitatory cells. Notably, other disease-associated genes such as BDNF and ERBB4 implicate specific interneuron synapses in psychiatric disorders. Consistent with this, cortical interneuron dysfunction has been linked to epilepsy, schizophrenia and autism. Using a microarray screen that focused upon synapse-associated molecules, we identified Cntnap4 (contactin associated protein-like 4, also known as Caspr4) as highly enriched in developing murine interneurons. In this study we show that Cntnap4 is localized presynaptically and its loss leads to a reduction in the output of cortical parvalbumin (PV)-positive GABAergic (γ-aminobutyric acid producing) basket cells. Paradoxically, the loss of Cntnap4 augments midbrain dopaminergic release in the nucleus accumbens. In Cntnap4 mutant mice, synaptic defects in these disease-relevant neuronal populations are mirrored by sensory-motor gating and grooming endophenotypes; these symptoms could be pharmacologically reversed, providing promise for therapeutic intervention in psychiatric disorders.

Intracranial self stimulation upregulates the expression of synaptic plasticity related genes and Arc protein expression in rat hippocampus.

Post-training lateral hypothalamus (LH) intracranial self stimulation (ICSS) has a reliable enhancing effect on explicit memory formation evaluated in hippocampus-dependent tasks such as the Morris water maze. In this study, the effects of ICSS on gene expression in the hippocampus are examined 4.5 h post treatment by using oligonucleotide microarray and real-time PCR, and by measuring Arc protein levels in the different layers of hippocampal subfields through immunofluorescence. The microarray data analysis resulted in 65 significantly regulated genes in rat ICSS hippocampi compared to sham, including cAMP-mediated signaling as one of the most significantly enriched Database for Annotation, Visualization and Integrated Discovery (DAVID) functional categories. In particular, expression of CREB-dependent synaptic plasticity related genes (c-Fos, Arc, Bdnf, Ptgs-2 and Crem and Icer) was regulated in a time-dependent manner following treatment administration. Immunofluorescence results showed that ICSS treatment induced a significant increase in Arc protein expression in CA1 and DG hippocampal subfields. This empirical evidence supports our hypothesis that the effect of ICSS on improved or restored memory functions might be mediated by increased hippocampal expression of activity-dependent synaptic plasticity related genes, including Arc protein expression, as neural mechanisms related to memory consolidation.

[Clozapine rechallenge in resistant schizophrenia disorder affecting "super sensitive" patients, after neutropenia under clozapine: a case report]. / Réintroduction de la clozapine chez les patients souffrant de schizophrénie résistante "super répondeurs", après neutropénie sous clozapine: à propos d'un cas.

INTRODUCTION AND OBJECTIVE: The frequency of agranulocytosis induced by psychoactive drugs is estimated the first year of around 0.8% under clozapine, against 0.13% under chlorpromazine (King and Wager, 1998 [3]). It is associated with a mortality rate of 5 to 10%, and requires heavy treatment, usually in an intensive care unit. The objective of this paper is to present a practical therapeutic answer (clozapine rechallenge with filgrastim) through a case report following a neutropenia episode preventing clozapine use. CASE AND METHODS: B.N. aged 35, native of Martinique, shows a resistant schizophrenia disorder "ultra sensitive" to clozapine. Without any treatment, after 4 years in stable clinical state under clozapine, B.N. suffered three neutropenia episodes when absorbing clozapine (2008, 2010 and 2011). First, a literature survey was conducted along with a consultation of the head of pharmacovigilance regional center and the hematology referee. Then, a 4th clozapine treatment was decided under cover of filgrastim (G-CSF), the role of which is to limit the risk of a new neutropenia. After stopping all psychoactive drugs, except morphine, the subject benefited from a first 0.3mg filgrastim injection, the day before re-introducing 25mg clozapine. Before treatment: Leucocytes=4.8 G/L while absolute neutrophils count=2.4 G/L. Filgrastim injections were carried out at a rate of two 0.3mg injections per week. Clozapine was increased to reach 25mg every 3 days and electroconvulsivotherapy continued fortnightly while supervision was double: on the first hand, daily and clinical search for an increase in body temperature and signs of treatment intolerance, and on the other hand biological surveillance with NFS three times a week besides weekly clozapinemia. The well-informed consent of the patient was obtained. RESULTS: Signs of improvement were noticed as early as the 8th day and after 8 weeks of treatment and 31 sessions of ECT, the patient was stabilized under clozapine at 300 mg per day. The evolution is clearly favorable, as PANNS evolved from 158 to 90. Neutropenia episodes were not observed with a lowest measured rate of 1.9 G/L neutrophils. The filgrastim dosage was then reduced to 0.3mg per week from the 7th week onwards, along with the pursuit of a weekly NFS supervision throughout the treatment. Tolerance is satisfying, with an improvement in lipid check, glycaemia, blood pressure and QT intervals during ECG. DISCUSSION AND CONCLUSION: The B.N. case isn't an isolated one as several articles refer to filgrastim use, combined with clozapine. This confirms the role of hematopoietic cytokines (mainly G-CSF) in neutropenia episodes induced by clozapine. Filgrastim dosage appears to be an important point with regards to the risk of a new neutropenia episode. Let's mention also that it is not a harmless treatment, it could hide the occurrence of neutropenia, besides it's expensive and invasive. Clinical and biological supervision is essential as the probability of an enhanced malignant hemopathy is low but nonetheless present. We also noticed a "biased notoriety of the clozapine", with the association with other hematotoxic molecules, the existence of a circadian rhythm of neutrophils or G-CSF, along with transitional or ethnical neutropenia. These points should be discussed thoroughly before exclusively accusing clozapine; this in turn would have consequences regarding the possibility of treatment resumption. Finally, association with lithium is also an option; several cases have already been reported.

Analysis of the chromosome X exome in patients with autism spectrum disorders identified novel candidate genes, including TMLHE.

The striking excess of affected males in autism spectrum disorders (ASD) suggests that genes located on chromosome X contribute to the etiology of these disorders. To identify new X-linked genes associated with ASD, we analyzed the entire chromosome X exome by next-generation sequencing in 12 unrelated families with two affected males. Thirty-six possibly deleterious variants in 33 candidate genes were found, including PHF8 and HUWE1, previously implicated in intellectual disability (ID). A nonsense mutation in TMLHE, which encodes the ɛ-N-trimethyllysine hydroxylase catalyzing the first step of carnitine biosynthesis, was identified in two brothers with autism and ID. By screening the TMLHE coding sequence in 501 male patients with ASD, we identified two additional missense substitutions not found in controls and not reported in databases. Functional analyses confirmed that the mutations were associated with a loss-of-function and led to an increase in trimethyllysine, the precursor of carnitine biosynthesis, in the plasma of patients. This study supports the hypothesis that rare variants on the X chromosome are involved in the etiology of ASD and contribute to the sex-ratio disequilibrium.

Intracranial self-stimulation induces expression of learning and memory-related genes in rat amygdala.

Intracranial self-stimulation (ICSS) in the lateral hypothalamus improves memory when administered immediately after a training session. In our laboratory, ICSS has been shown as a very reliable way to increase two-way active avoidance (TWAA) conditioning, an amygdala-dependent task. The aim of this work was to study, in the rat amygdala, anatomical and molecular aspects of ICSS, using the same parameters facilitating TWAA. First, we examined the activation of ipsilateral and contralateral lateral (LA) and basolateral (BLA) amygdala, the main amygdalar regions involved in the TWAA, by the immunohistochemical determination of c-Fos protein expression. Second, we tested the effects of the ICSS treatment on the expression of 14 genes related to learning and memory processes using real-time polymerase chain reaction. Results showed a bilateral increase in c-Fos protein expression in LA and BLA nuclei after ICSS treatment. We also found that Fos, brain-derived nerve growth factor (BDNF), Arc, inducible cAMP early repressor (ICER), COX-2, Dnajb1, FKpb5 and Ret genes were upregulated in the amygdala 90 min and 4.5 h post ICSS. From this set of genes, BDNF, Arc and ICER are functionally associated with the cAMP-responsive element-mediated gene transcription molecular pathway that plays a pivotal role in memory, whereas Dnajb1 and Ret are associated with protein folding required for plasticity or neuroprotection. Our results suggest that ICSS induces expression of genes related with synaptic plasticity and protein folding functions in the rat amygdaloid area, which may be involved in the molecular mechanisms by which ICSS may improve or restore memory functions related to this brain structure.

Intracranial self-stimulation to the lateral hypothalamus, a memory improving treatment, results in hippocampal changes in gene expression.

Intracranial self-stimulation (ICSS) within the medial forebrain bundle of the lateral hypothalamus (LH) facilitates consolidation of implicit and explicit memories for a variety of learning paradigms in rats. However, the neural and molecular mechanisms involved in memory facilitation by ICSS are not known. Here, we investigated the influence of ICSS treatment on hippocampal gene expression in order to identify potential signaling pathways and cellular processes involved in ICSS-mediated cognitive improvements. Immunohistochemistry studies demonstrated that ICSS caused a rapid induction of c-Fos expression in hippocampal cornu ammonis (CA) 3 and dentatus gyrus areas. Moreover, using microarray or quantitative real-time polymerase chain reaction (PCR) analysis, we showed that ICSS modulates the expression of 62 hippocampal genes shortly after training. Most of the proteins encoded by these genes, such as calmodulin-dependent-phosphodiesterase 1 A (Pde1a), are part of signal transduction machineries or are related to anti-apoptosis, as heat shock 70 kDa protein 1A (Hspa1a). Importantly, 10 of the regulated genes have been previously related with learning and memory or neural plasticity, including the cocaine and amphetamine-regulated transcript (Cart), adenylate cyclase activating polypeptide 1 (Adcyap1), serum/glucocorticoid regulated kinase (Sgk), Ret proto-oncogene (Ret), and Fos. The fact that the Fos gene was differentially expressed in our microarray experiments validated our findings from our immunohistochemical studies mentioned above. In addition, using quantitative real-time PCR, we confirmed the observed expression changes for several of the genes identified by our microarray analyses. Our results suggest that ICSS may facilitate learning and memory by regulation of multiple signaling pathways in the hippocampus that may promote neuroplasticity.

Wound healing after silver nitrate burns in the leech hirudo medicinalis

The healing process after inflicting silver nitrate burns, a type of injury in which a heavy loss of body wall tissues occurs, was studied in Hirudo medicinalis. Silver solution penetrates the body wall and silver precipitates in the tissues during infiltration. Vasocentral cells, do not penetrate the impregnated zone but accumulate just below it to form a pseudoblastema. The impregnated zone splits off entirely, leaving an area covered by pseudoblastema cells on the leech surface, which is progressively reepithelialized. There is no regeneration of the lost body region, and although some connective tissue matrix may be produced by pseudoblastema cells, there is no significant regeneration of the connective tissue and nor the muscular fibers of the body wall, resting an evident depression in the damaged zone. The amount of affected tissue, and possibly the inability of vasocentral cells to reach the infiltrated tissues are determinant factors in the development of the splitting process. Copyright 1999 Academic Press.

Morning versus afternoon gymnastic time and diurnal and seasonal changes in psychophysiological variables of school children.

The aims of this study were to document time-related (morning versus afternoon) effects of physical activities (gymnastics) on a set of physiological and psychological variables in school children, including diurnal changes. For the study, 61 boys and 69 girls, 6 to 11 years of age, volunteered. They were considered healthy according to routine clinical criteria. They were synchronized with diurnal activity from around 07:00 to 21:00 and nocturnal rest, time of year being taken into account. Tests were performed at school during 4 weeks of 4.5 days of school at fixed clock hours: 09:00, 11:00, 14:00, and 16:00. Gym time was randomized with regard to week order and season. Four different classes (39 boys and 38 girls) were involved in psychophysiological tests, and two different classes (22 boys and 31 girls) collected saliva samples for morning free cortisol determination. Both t-test and three-factor analysis of variance (ANOVA) were used for statistical analyses. Better performances were obtained in June than in mid-winter with reference to letter cancellation and random number addition tests. As a group phenomenon, morning (09:00 to 10:00) versus afternoon (14:00 to 15:00) gym was not an influential condition with regard to sleep duration, oral temperature, self-rated fatigue and drowsiness, letter cancellation, addition tests, or salivary cortisol. However, gym-time-related differences were observed in classes of younger subjects (e.g., 6-7 years) with regard to self-rated fatigue and the letter cancellation test. Such variability among subgroups suggests that interindividual differences are likely to exist in younger children with regard to manipulation of environmental factors. In addition, gym itself (without gym time consideration) may be an influential factor with regard to diurnal patterns of some variables (e.g., the letter cancellation test).

The pseudoblastema in the wound healing process of the leech Hirudo medicinalis L. (Hirudinea): changes in cell junctions.

The role of the connective tissue cells and their migratory behavior have been investigated in the formation and evolution of the pseudoblastema during wound healing in the leech Hirudo medicinalis. In H. medicinalis the healing process shows first a flow of cells that effectively seal the wound and form a temporary cellular clump, the pseudoblastema, which contributes to the phagocytotic process and apparently regenerates the extracellular matrix. The migratory cells forming the pseudoblastema are connective tissue cells known as vasocentral cells, which, when in a resting state, are associated with the vasofibrous cells. During the formation and evolution of the pseudoblastema several changes affect vasocentral cell junctions. At rest, vasocentral cells do not show cell to cell junctions but they show adhering junctions in contact with the extracellular matrix. These junctions disrupt during the migratory phase. When vasocentral cells regroup in the pseudoblastema, adhering junctions are formed between them, and adhering junctions making contact with the matrix appear again. As the pseudoblastema evolves, cell to cell adhering junctions become more conspicuous and undergo other changes. During the next stage of retraction, close contacts develop between pseudoblastema cells and neighboring nondamaged muscle fibers, which probably serve as points of anchorage for the approaching movement of the wound edges. Finally, cell to cell and cell to matrix junctions disappear and the pseudoblastema disintegrates.

Ultrastructure and cytochemistry of secretory cells in the skin of the leech, Dina lineata.

The ultrastructure and histochemical features of the two types of secretory cells in leech skin are described. Pear-shaped cells secrete mucus containing carboxylated mucosubstances, while tubular cells produce a mucus containing a mixture of neutral, carboxylated, and sulfated mucosubstances. Pear-shaped secretory cells have two types of neuroglandular junctions, one containing dense-core serotonergic vesicles and the other small clear vesicles. Tubular secretory cells have large terminals, with many clear vesicles thought to be cholinergic. © 1993 Wiley-Liss, Inc.

Changes in epithelial cells in Hirudo medicinalis during wound healing.

In the leech, Hirudo medicinalis, reepithelialization is an event which takes place early in the wound healing process, immediately after the formation of the pseudoblastema, 4-8 hr postinjury. Epithelial cells on the wound margins move into the wound, modifying their phenotypic characteristics. Cells lose their columnar shape and become flattened. Dermal junctions disrupt and tonofilaments regroup around the nucleus. Then, the epithelial cell sheet moves over the newly formed pseudoblastema by extending filopodia, formed by the cells on the edge, following the so-called "sliding model." When the wound is fully covered by the new epithelium, about 24 hr postinjury, a reorganization of the cytoskeleton occurs and the basal dermal junctions are reconstructed. Six days postinjury, the epidermal cells return to their original columnar shape.