Proteomics insights into fragile X syndrome: Unraveling molecular mechanisms and therapeutic avenues

Fragile X Syndrome (FXS) is a neurodevelopment disorder characterized by cognitive impairment, behavioral challenges, and synaptic abnormalities, with a genetic basis linked to a mutation in the FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene that results in a deficiency or absence of its protein product, Fragile X Messenger Ribonucleoprotein (FMRP). In recent years, mass spectrometry (MS) - based proteomics has emerged as a powerful tool to uncover the complex molecular landscape underlying FXS. This review provides a comprehensive overview of the proteomics studies focused on FXS, summarizing key findings with an emphasis on dysregulated proteins associated with FXS. These proteins span a wide range of cellular functions including, but not limited to, synaptic plasticity, RNA translation, and mitochondrial function. The work conducted in these proteomic studies provides a more holistic understanding to the molecular pathways involved in FXS and considerably enhances our knowledge into the synaptic dysfunction seen in FXS.

Disentangling the relationship between sensory processing, alexithymia and broad autism spectrum: A study in parents' of children with autism spectrum disorders and sensory processing disorders

BACKGROUND

Autistic features and sensory processing difficulties and their phenotypic co-expression with alexithymia share a transdiagnostic vulnerability. In this work, we explored whether the current concept of broad autism phenotype rather translates altered sensory processing (non-specific to autism), meaning that the characteristics of altered sensory processing should be overexpressed among individuals with heightened vulnerability to sensory processing atypicalities (parents of children with sensorial processing disorder, or SPD parents) and individuals with heightened vulnerability to autistic traits (parents of children with autism spectrum disorders, or ASD parents). In addition, the association between altered sensory processing and alexithymia was inspected.

METHOD

The Adolescent/Adult Sensory Profile, Autism Spectrum Quotient, and Toronto Alexithymia Scale were completed by 31 parents of children with ASD, 32 parents of children with SPD, and 52 parents of typically developed (TD) children.

RESULTS

Extreme sensory patterns were overexpressed both in parents of children with SPD and parents of children with ASD when compared to parents of TD children. In addition, extreme sensory patterns were significantly associated with alexithymia scores. Specifically, sensory avoidance, low registration, and sensory sensitivity were positively correlated with alexithymia. No significant differences were found regarding the proportion of autistic traits and alexithymia between ASD and SPD groups of parents.

CONCLUSIONS

These results challenge the specificity of broad autism phenotype and suggest a neurodevelopmental atypicity with roots in altered sensory and emotional processing.

The effects of persistent sleep disturbances during early childhood over adolescent ADHD, and the mediating effect of attention-related executive functions: Data from the 2004 Pelotas Birth Cohort

OBJECTIVE

Investigate effects of persistent sleep disturbances during early childhood over ADHD during the adolescence, and the potential attention-related executive functions mediating this effect.

METHODS

We used data from the 2004 Pelotas Birth Cohort. Children's Sleep disturbances were reported by their mothers at 12, 24, and 48 months of age, whereas the Test-of-Everyday-Attention-for-Children (TEA-Ch) and the Development and Well Being Assessment (DAWBA) were applied at 11 years of age to evaluate attention-related executive functions and ADHD, respectively. Persistent sleep problems were defined as reporting have two or more points of difficulty to sleep, nightmares, restless sleeps, and/or <10h/24h sleep duration. Logistic regression and mediation models were used, adjusting for maternal and child sociodemographic, behavior and health related variables.

RESULTS

The highest prevalence of adolescent ADHD (15.4%) was on the group who reported having nightmares at 2,4 and 6 years. In adjusted models, we observed an odd of ADHD in the adolescence 2.26 higher in those who reported persistent nightmares (CI95% 1.33, 4.01) compared to those reported transitory or no nightmares. Persistent difficulty to sleep (OR=1.74 CI95% 1.13, 2.66) and restless sleep (OR=1.80, CI95% 1.23, 2.64) during childhood also increased ADHD odds at 11 years. No indirect effect through attention related executive functions was found using mediating models.

DISCUSSION

Persistent early sleep disturbances may increase odds of ADHD among adolescents and could be consider as early marker of such disorder, specially nightmares problems. These effects were not mediated by attention-related executive functions. Nevertheless, we had 75% of cohort inception response.

Neurodevelopmental and psychiatric disorders in pediatric bladder and bowel dysfunction

BACKGROUND

Bladder and bowel dysfunction (BBD) is a common pediatric problem that describes a constellation of lower urinary tract symptoms associated with constipation and/or encopresis. Its association with neurodevelopmental and psychiatric (NDP) problems is not well understood.

OBJECTIVES

Our primary aim was to identify pre-existing NDP disorders in children with BBD. Secondarily, we aimed to screen for new behavioral problems and evaluate the association between bladder or bowel symptoms and behaviors symptoms.

METHODS

A cross sectional study was conducted in urology clinics. New patients referred for BBD between 4 and 17 years old were recruited and completed: a demographics survey, Dysfunctional Voiding Score System questionnaire, assessment of bowel movements with the Bristol Stool Scale, and Strength and Difficulties questionnaire (SDQ). Those with known spinal dysraphism were excluded. SDQ scores were evaluated for abnormal screens in different subscales and total difficulties scores. Pearson correlation analyses were conducted for association.

RESULTS

We included 61 participants (age 9.5 ± 4.1 years), including 33 females and 28 males. One or more pre-existing NDP disorder(s) was reported in 14 (23%) children; most commonly being learning disability (43%) and attention deficit hyperactivity disorder (29%). This cohort had more severe BBD symptoms as reflected in DVSS scores. SDQ scores demonstrated that 12 patients without pre-existing NDP diagnoses scored in the clinical range, with hyperactivity as the most common difficulty (6/12; 50%).

CONCLUSIONS

A significant proportion of children with BBD have a comorbid NDP disorder and present with more severe symptomatology. The SDQ can be used as a behavioral screening tool this population for the identification of children who may benefit from formal developmental pediatrics assessment.

The thalamic reticular nucleus: A common nucleus of neuropsychiatric diseases and deep brain stimulation

This review focuses on the studies that have been reviewed to determine the influence of the thalamic reticular nucleus on neuropsychiatric diseases and deep brain stimulation. The literature reviewed to date describes how alterations in the thalamic reticular nucleus affect several functions that regulated brain rhythms and provokes symptoms of many disorders. The observations as the basis for the renewed interest in the thalamic reticular nucleus in experimental models and testing its effectiveness in patients with resistant neuropsychiatric disorders. The preclinical studies showed that deep brain stimulation in the thalamic reticular nucleus could have beneficial effects on EEG activity, including synchronization and desynchronization activity of the brain, as well as promoting an alleviate to neuropsychiatric diseases. These observations open up the possibility of studying the role played by neurotransmitters in the pathologic process and the deep brain stimulation in the thalamic reticular nucleus in experimental animal models and offer evidence of its possible action in the human brain.

Assessing drug response in engineered brain microenvironments

Tissue engineered systems are important models for the testing and discovery of therapeutics against a number of diseases. The use of these models in vitro can expand both our understanding of the mechanisms behind disease and allow for higher throughput and personalized modeling of therapeutic response. Over the past decade there has been an explosion of models of neurological disorders that can be used in vitro to study new therapies against devastating neurodegenerative, neurodevelopmental, and neuro-oncological disease. These models span several types of engineered microenvironments which are produced using microfluidic devices, microtissue technology and/or the incorporation of biomaterial scaffolds to model neurological conditions such as; Alzheimer's disease, idiopathic autism, Parkinson's disease, Zika-induced microcephaly and neoplasms. Using engineered brain microenvironments, therapeutics can be tested in more physiologically relevant ways leading to new knowledge of the underlying causes and interactions occurring at the tissue level. However, much is still left to learn and model within these systems to make them truly valuable in the discovery and testing of novel therapies. Here we review the current state of the art of engineered brain microenvironments being used specifically to screen and test new therapeutic strategies and discuss the current benefits and limitations that still exist.

How do hypothalamic nonapeptides shape youth's sociality? A systematic review on oxytocin, vasopressin and human socio-emotional development

The hypothalamic nonapeptides oxytocin and vasopressin are important modulators of socio-affective behaviours in a wide variety of animal species, including humans. Nevertheless, there is little research addressing their possible roles on socio-affective dimensions of human behaviour across development, during which considerable behavioural and physiological change occurs. Questions still remain about the extent to which findings from adults may directly apply to earlier phases of human development. In this article, we systematically summarize and discuss all existing studies investigating the developmental association of endogenous levels of hypothalamic neuropeptides oxytocin and vasopressin with human social behaviour or on its disruption in paediatric populations. Evidence is sparse insofar as there are still relatively few developmental studies and limited due to correlational research designs and unreliability of methods currently used for neuropeptide measurements in biological fluids. The findings to date generally converge with adult evidence, but also suggest that important differences between age stages may exist. Further studies focusing these differences may prove critical for informing drug development for socio-affective deficits in paediatric populations.

Children born extremely preterm had different sleeping habits at 11 years of age and more childhood sleep problems than term-born children

AIM

This study explored whether extremely preterm (EPT) children had different sleep characteristics in childhood than children born at term and how neurodevelopmental disabilities (NDD) affected sleep in children born EPT.

METHODS

A Norwegian national cohort of 231 children born EPT from 1999 to 2000 and separate study data on 556 children born at term in 2001 were compared. Parental questionnaires mapped the children's current sleep habits at 11 years of age, namely the prevalence of sleep problems throughout childhood until this age and five categories of sleep problems. In addition, the EPT children were clinically assessed at five years of age.

RESULTS

The EPT children had different sleep habits than the controls, for example they went to bed earlier. EPT children had a higher prevalence of sleep problems than the controls throughout childhood (26% versus 14%, p < 0.001) and this was also higher for the 93 EPT children with no NDD (20%) than for the controls (14%) and increased with increasing NDD to 67% (p = 0.015) for the six children with severe NDD.

CONCLUSION

EPT children had different sleep habits to term-born controls at 11 years of age, including those with no NDD. The prevalence of sleep problems increased with increasing NDD.

Clinical manifestations in children and adolescents with corpus callosum abnormalities

Corpus callosum abnormality (CCA) outcomes are quite unpredictable and variable, from asymptomatic forms to mild or severe neurodevelopment disorders. The aim of this study was to examine clinical outcomes in CCA patients. The study included 61 children and adolescents in whom brain magnetic resonance imaging (MRI) scans showed CCA, isolated or associated to other central nervous system lesions. All patients underwent anamnesis, physical and neurological examination, routine laboratory tests, electroencephalogram (EEG), and MRI scans. In all participants, the intelligence quotient (IQ) was determined. We divided the participants into two subgroups: the first subgroup included patients with an isolated CCA, and the second subgroup included patients with CCA associated with extra-callosal brain lesions (complex CCA). We found that CCA were associated with elevated frequency to intellectual disability (ID), other neurodevelopment disorders, epilepsy, and isolated EEG anomalies. Mild ID (p = 0.003) was more frequent in the isolated subgroup, while epilepsy (p = 0.036) and pre-perinatal risk factors (p = 0.023) were more frequent in the complex CCA subgroup. Although the role of the CC in the interhemispheric communication is known, neurological and neurodevelopment outcomes of CCA are extremely variable and unpredictable. The presence of extra-callosal brain anomalies is one of the major prognostic factor, and probably, they have an important impact on the clinical outcome.

Acid glycosaminoglycan (aGAG) excretion is increased in children with autism spectrum disorder, and it can be controlled by diet

Autism research continues to receive considerable attention as the options for successful management are limited. The understanding of the autism spectrum disorder (ASD) etiology has now progressed to encompass genetic, epigenetic, neurological, hormonal, and environmental factors that affect outcomes for patients with ASD. Glycosaminoglycans (GAGs) are a family of linear, sulfated polysaccharides that are associated with central nervous system (CNS) development, maintenance, and disorders. Proteoglycans (PG) regulate diverse functions in the central nervous system. Heparan sulfate (HS) and chondroitin sulfate (CS) are two major GAGs present in the PGs of the CNS. As neuroscience advances, biochemical treatments to correct brain chemistry become better defined. Nutrient therapy can be very potent and has minimal to no side effects, since no molecules foreign to the body are needed. Given GAGs are involved in several neurological functions, and that its level can be somewhat modulated by the diet, the present study aimed to evaluate the role of GAGs levels in ASD symptoms. Both tGAG and its different fractions were evaluated in the urine of ASD and healthy control childrens. As levels differed between groups, a second trial was conduted evaluating if diet could reduce tGAG levels and if this in turn decrease ASD symptoms. The present study found that tGAG concentration was significantly higher in the urine of children with ASD compared to healthy control children and this was also evident in all GAG fractions. Within groups (controls and ASD), no gender differences in GAG excretion were found. The use of a 90 days elimination diet (casein-free, special carbohydrates, multivitamin/mineral supplement), had major effects in reducing urinary tGAG excretion in children with ASD.