Anxious to see you: Neuroendocrine mechanisms of social vigilance and anxiety during adolescence.

Social vigilance is a behavioral strategy commonly used in adverse or changing social environments. In animals, a combination of avoidance and vigilance allows an individual to evade potentially dangerous confrontations while monitoring the social environment to identify favorable changes. However, prolonged use of this behavioral strategy in humans is associated with increased risk of anxiety disorders, a major burden for human health. Elucidating the mechanisms of social vigilance in animals could provide important clues for new treatment strategies for social anxiety. Importantly, during adolescence the prevalence of social anxiety increases significantly. We hypothesize that many of the actions typically characterized as anxiety behaviors begin to emerge during this time as strategies for navigating more complex social structures. Here, we consider how the social environment and the pubertal transition shape neural circuits that modulate social vigilance, focusing on the bed nucleus of the stria terminalis and prefrontal cortex. The emergence of gonadal hormone secretion during adolescence has important effects on the function and structure of these circuits, and may play a role in the emergence of a notable sex difference in anxiety rates across adolescence. However, the significance of these changes in the context of anxiety is still uncertain, as not enough studies are sufficiently powered to evaluate sex as a biological variable. We conclude that greater integration between human and animal models will aid the development of more effective strategies for treating social anxiety

Variation in early life maternal care predicts later long range frontal cortex synapse development in mice.

Empirical and theoretical work suggests that early postnatal experience may inform later developing synaptic connectivity to adapt the brain to its environment. We hypothesized that early maternal experience may program the development of synaptic density on long range frontal cortex projections. To test this idea, we used maternal separation (MS) to generate environmental variability and examined how MS affected 1) maternal care and 2) synapse density on virally-labeled long range axons of offspring reared in MS or control conditions. We found that MS and variation in maternal care predicted bouton density on dorsal frontal cortex axons that terminated in the basolateral amygdala (BLA) and dorsomedial striatum (DMS) with more, fragmented care associated with higher density. The effects of maternal care on these distinct axonal projections of the frontal cortex were manifest at different ages. Maternal care measures were correlated with frontal cortex → BLA bouton density at mid-adolescence postnatal (P) day 35 and frontal cortex → DMS bouton density in adulthood (P85). Meanwhile, we found no evidence that MS or maternal care affected bouton density on ascending orbitofrontal cortex (OFC) or BLA axons that terminated in the dorsal frontal cortices. Our data show that variation in early experience can alter development in a circuit-specific and age-dependent manner that may be relevant to understanding the effects of early life adversity

Developmental differences in the control of action selection by social information

Our everyday actions are often performed in the context of a social interaction. We previously showed that, in adults, selecting an action on the basis of either social or symbolic cues was associated with activations in the fronto-parietal cognitive control network, whereas the presence and use of social versus symbolic cues was in addition associated with activations in the temporal and medial prefrontal cortex (MPFC) social brain network. Here we investigated developmental changes in these two networks. Fourteen adults (21–30 years of age) and 14 adolescents (11–16 years) followed instructions to move objects in a set of shelves. Interpretation of the instructions was conditional on the point of view of a visible “director” or the meaning of a symbolic cue (Director Present vs. Director Absent) and the number of potential referent objects in the shelves (3-object vs. 1-object). 3-object trials elicited increased fronto-parietal and temporal activations, with greater left lateral prefrontal cortex and parietal activations in adults than adolescents. Social versus symbolic information led to activations in superior dorsal MPFC, precuneus, and along the superior/middle temporal sulci. Both dorsal MPFC and left temporal clusters exhibited a Director × Object interaction, with greater activation when participants needed to consider the directors' viewpoints. This effect differed with age in dorsal MPFC. Adolescents showed greater activation whenever social information was present, whereas adults showed greater activation only when the directors' viewpoints were relevant to task performance. This study thus shows developmental differences in domain-general and domain-specific PFC activations associated with action selection in a social interaction context

Controlled trial of lovastatin combined with an open-label treatment of a parent-implemented language intervention in youth with fragile X syndrome.

BackgroundThe purpose of this study was to conduct a 20-week controlled trial of lovastatin (10 to 40 mg/day) in youth with fragile X syndrome (FXS) ages 10 to 17 years, combined with an open-label treatment of a parent-implemented language intervention (PILI), delivered via distance video teleconferencing to both treatment groups, lovastatin and placebo.MethodA randomized, double-blind trial was conducted at one site in the Sacramento, California, metropolitan area. Fourteen participants were assigned to the lovastatin group; two participants terminated early from the study. Sixteen participants were assigned to the placebo group. Lovastatin or placebo was administered orally in a capsule form, starting at 10 mg and increasing weekly or as tolerated by 10 mg increments, up to a maximum dose of 40 mg daily. A PILI was delivered to both groups for 12 weeks, with 4 activities per week, through video teleconferencing by an American Speech-Language Association-certified Speech-Language Pathologist, in collaboration with a Board-Certified Behavior Analyst. Parents were taught to use a set of language facilitation strategies while interacting with their children during a shared storytelling activity. The main outcome measures included absolute change from baseline to final visit in the means for youth total number of story-related utterances, youth number of different word roots, and parent total number of story-related utterances.ResultsSignificant increases in all primary outcome measures were observed in both treatment groups. Significant improvements were also observed in parent reports of the severity of spoken language and social impairments in both treatment groups. In all cases, the amount of change observed did not differ across the two treatment groups. Although gains in parental use of the PILI-targeted intervention strategies were observed in both treatment groups, parental use of the PILI strategies was correlated with youth gains in the placebo group and not in the lovastatin group.ConclusionParticipants in both groups demonstrated significant changes in the primary outcome measures. The magnitude of change observed across the two groups was comparable, providing additional support for the efficacy of the use of PILI in youth with FXS.Trial registrationUS National Institutes of Health (ClinicalTrials.gov), NCT02642653. Registered 12/30/2015

Inflammatory Response as a Mechanism of Perinatal Programming: Long-term Impact on Pulmonary and Renal Function?

RATIONALE: Temporal changes in the fetal environment, such as malnutrition and placental insufficiency induce intrauterine growth restriction (IUGR) and lead to a permanent changes of physiological processes later in life. Interestingly, epidemiological studies demonstrated an impairment of lung and renal function in young infants subsequent to IUGR. Complementary, experimental studies showed that IUGR induces a perinatal programming of the developing lung with persisting impairment of pulmonary structure and function. Besides IUGR, early postnatal hyperalimentation (pHA) is discussed as a crucial factor of IUGR-associated diseases. Both extracellular matrix (ECM) and inflammatory processes have been shown to be dysregulated following IUGR and early pHA. However, the underlying molecular mechanisms of IUGR-associated diseases and the potential linkage of ECM and inflammation have not been addressed so far. Therefore, the ultimate goal of this project was to elucidate the role of regulation of ECM and inflammatory cytokines subsequent to IUGR and early pHA. AIMS: There are three specific aims: (1) to analyze the role of the TGF-β signaling in lung development subsequent to IUGR, (2) to determine the regulation of inflammatory cytokines and ECM-molecules in lungs subsequent to IUGR, and (3) to characterize the pathomechanistic role of early pHA using the example of the kidney. METHODS: Two simultaneous sets of animal experiments were used. One animal model addressed pre- and postnatal nutritional intervention, the other was restricted to postnatal interventions only: (A) IUGR was induced in Wister rats by isocaloric low protein diet (8% casein; IUGR) during gestation. The control group received normal protein diet (17% casein; Co). At birth the litter size was reduced to 6 male pups to induce early pHA. During lactation the mothers of both groups were fed standard chow. (B) Early pHA was induced by litter size reduction to 6 (LSR6) or 10 (LSR10) male neonates. Home-cage control (HCC; mean litter size of 16) animals without any postnatal manipulation during lactation were included. At postnatal day (P) 28 as well as P70 animals underwent whole body plethysmography and in addition metabolic cages at P70. Serum and samples of lungs and kidney were obtained at P1, P12, P21, P42, and P70 for mRNA extraction, protein extraction as well as histological analyses. RESULTS: Both respiratory system resistance and compliance were impaired subsequent to IUGR at P28; this impairment was even more significant at P70. (1) These changes were accompanied by persistent attenuated activity of the TGF-β signaling, assessed by phosphorylation of Smad2 and Smad3. Expression analysis of TGF-β-regulated ECM components in the lungs of IUGR animals at P1, such as collagen I, elastin, and tenascin N, revealed a significant deregulation. Consistently, in vitro inhibition of TGF-β signaling in NIH/3T3, MLE 12 and endothelial cells by adenovirus-delivered Smad7 demonstrated a direct effect on the expression of ECM components. Interestingly, however, not just a deregulation of ECM components was detected at P1, but also attenuated apoptotic processes, e.g. decreased cleavage of PARP. (2) Since the TGF-β signaling has potent anti-inflammatory effects, we next determined the dynamic expression of pro-inflammatory and pro-fibrotic markers as well of ECM components in the lung subsequent to IUGR at P1, P42 and P70. The expression of ECM components and metabolizing enzymes was markedly deregulated and the deposition of collagen I was strikingly increased at P70. Concomitantly to the pro-fibrotic processes in the lung subsequent to IUGR, the expression of inflammatory cytokines and both the activity and the expression of target genes of Stat3 signaling were dynamically regulated, with unaltered or decreased expression at P1 and significantly increased expression art P70. (3) Assessment of renal function at postnatal day 70 revealed decreased glomerular filtration rate, proteinuria, and increased fractional sodium and potassium secretion following early pHA (LSR6). Moreover, the deposition of ECM molecules, such as collagen I, was increased. Interestingly, despite the elevated expression of pro-inflammatory leptin and IL-6 expression the phosphorylation of Stat3 and ERK1/2 in the kidney, however, was decreased after LSR6. In accordance, neuropeptide Y (NPY) gene expression – sympathetic co-neurotransmitter regulated by Stat3 signaling – was down-regulated. In accordance, suppressor of cytokine signaling (SOCS)3 protein expression, an inhibitor of Stat3 and Erk1/2 signaling, was strongly elevated and colocalized with NPY. Interestingly, NPY is co- localized with SOCS3 in the distal tubules in the cortex and outer medulla, and in the proximal tubules, but no expression of SOCS3 was detectable in glomeruli. CONCLUSION: Taken together, IUGR has a direct and strong negative impact on respiratory resistance and compliance of the lung. There are two major underlying mechanisms linking IUGR and deregulation of ECM: first, the attenuated TGF-β signaling during late lung development; and second, the increased expression of inflammatory cytokines subsequent to IUGR. In addition, the missing anti-inflammatory effect of TGF-β signaling could contribute to the increased inflammatory response following IUGR. Furthermore we demonstrated that early pHA leads to organ-intrinsic increased expression of NPY via a postreceptor-leptin-receptor leptin resistance. This leptin resistance could contribute to the observed profibrotic processes, and ultimately to a long-term impairment of renal function. Thus, both IUGR and early postnatal hyperalimentation have a strong impact on perinatal programming of multi-organ inflammatory response

Potential therapeutic use of the ketogenic diet in autism spectrum disorders.

The ketogenic diet (KGD) has been recognized as an effective treatment for individuals with glucose transporter 1 (GLUT1) and pyruvate dehydrogenase (PDH) deficiencies as well as with epilepsy. More recently, its use has been advocated in a number of neurological disorders prompting a newfound interest in its possible therapeutic use in autism spectrum disorders (ASD). One study and one case report indicated that children with ASD treated with a KGD showed decreased seizure frequencies and exhibited behavioral improvements (i.e., improved learning abilities and social skills). The KGD could benefit individuals with ASD affected with epileptic episodes as well as those with either PDH or mild respiratory chain (RC) complex deficiencies. Given that the mechanism of action of the KGD is not fully understood, caution should be exercised in ASD cases lacking a careful biochemical and metabolic characterization to avoid deleterious side effects or refractory outcomes

Modulation of the GABAergic pathway for the treatment of fragile X syndrome.

Fragile X syndrome (FXS) is the most common genetic cause of intellectual disability and the most common single-gene cause of autism. It is caused by mutations on the fragile X mental retardation gene (FMR1) and lack of fragile X mental retardation protein, which in turn, leads to decreased inhibition of translation of many synaptic proteins. The metabotropic glutamate receptor (mGluR) hypothesis states that the neurological deficits in individuals with FXS are due mainly to downstream consequences of overstimulation of the mGluR pathway. The main efforts have focused on mGluR5 targeted treatments; however, investigation on the gamma-aminobutyric acid (GABA) system and its potential as a targeted treatment is less emphasized. The fragile X mouse models (Fmr1-knock out) show decreased GABA subunit receptors, decreased synthesis of GABA, increased catabolism of GABA, and overall decreased GABAergic input in many regions of the brain. Consequences of the reduced GABAergic input in FXS include oversensitivity to sensory stimuli, seizures, and anxiety. Deficits in the GABA receptors in different regions of the brain are associated with behavioral and attentional processing deficits linked to anxiety and autistic behaviors. The understanding of the neurobiology of FXS has led to the development of targeted treatments for the core behavioral features of FXS, which include social deficits, inattention, and anxiety. These symptoms are also observed in individuals with autism and other neurodevelopmental disorders, therefore the targeted treatments for FXS are leading the way in the treatment of other neurodevelopmental syndromes and autism. The GABAergic system in FXS represents a target for new treatments. Herein, we discuss the animal and human trials of GABAergic treatment in FXS. Arbaclofen and ganaxolone have been used in individuals with FXS. Other potential GABAergic treatments, such as riluzole, gaboxadol, tiagabine, and vigabatrin, will be also discussed. Further studies are needed to determine the safety and efficacy of GABAergic treatments for FXS

Dystonia: sparse synapses for D2 receptors in striatum of a DYT1 knock-out mouse model

Dystonia pathophysiology has been partly linked to downregulation and dysfunction of dopamine D2 receptors in striatum. We aimed to investigate the possible morpho-structural correlates of D2 receptor downregulation in the striatum of a DYT1 Tor1a mouse model. Adult control Tor1a+/+ and mutant Tor1a+/− mice were used. The brains were perfused and free-floating sections of basal ganglia were incubated with polyclonal anti-D2 antibody, followed by secondary immune-fluorescent antibody. Confocal microscopy was used to detect immune-fluorescent signals. The same primary antibody was used to evaluate D2 receptor expression by western blot. The D2 receptor immune-fluorescence appeared circumscribed in small disks (~0.3–0.5 μm diameter), likely representing D2 synapse aggregates, densely distributed in the striatum of Tor1a+/+ mice. In the Tor1a+/− mice the D2 aggregates were significantly smaller (μm2 2.4 ± SE 0.16, compared to μm2 6.73 ± SE 3.41 in Tor1a+/+) and sparse, with ~30% less number per microscopic field, value correspondent to the amount of reduced D2 expression in western blotting analysis. In DYT1 mutant mice the sparse and small D2 synapses in the striatum may be insufficient to “gate” the amount of presynaptic dopamine release diffusing in peri-synaptic space, and this consequently may result in a timing and spatially larger nonselective sphere of influence of dopamine action