MAP1B and NOS1 genes are associated with working memory in youths with attention-deficit/hyperactivity disorder

Caffeine Consumption and Interaction with ADORA2A, CYP1A2 and NOS1 Variants Do Not Influence Age at Onset of Machado-Joseph Disease

BACKGROUND

The age at onset (AO) of Machado-Joseph disease (SCA3/MJD), a disorder due to an expanded CAG repeat (CAGexp) in ATXN3, is quite variable and the role of environmental factors is still unknown. Caffeine was associated with protective effects against other neurodegenerative diseases, and against SCA3/MJD in transgenic mouse models. We aimed to evaluate whether caffeine consumption and its interaction with variants of caffeine signaling/metabolization genes impact the AO of this disease.

METHODS

a questionnaire on caffeine consumption was applied to adult patients and unrelated controls living in Rio Grande do Sul, Brazil. AO and CAGexp were previously determined. SNPs rs5751876 (ADORA2A), rs2298383 (ADORA2A), rs762551 (CYP1A2) and rs478597 (NOS1) were genotyped. AO of subgroups were compared, adjusting the CAGexp to 75 repeats (p < 0.05).

RESULTS

171/179 cases and 98/100 controls consumed caffeine. Cases with high and low caffeine consumption (more or less than 314.5 mg of caffeine/day) had mean (SD) AO of 35.05 (11.44) and 35.43 (10.08) years (p = 0.40). The mean (SD) AO of the subgroups produced by the presence or absence of caffeine-enhancing alleles in ADORA2A (T allele at rs5751876 and rs2298383), CYP1A2 (C allele) and NOS1 (C allele) were all similar (p between 0.069 and 0.516).

DISCUSSION

Caffeine consumption was not related to changes in the AO of SCA3/MJD, either alone or in interaction with protective genotypes at ADORA2A, CYP1A2 and NOS1.

Role of Glutamate Receptor-related Biomarkers in the Etiopathogenesis of ADHD

Objective

: Pathways associated with glutamate receptors are known to play a role in the pathophysiology of attention-deficit hyperactivity disorder (ADHD). However, cyclin-dependent kinase 5 (CDK5), microtubule-associated protein-2 (MAP2), guanylate kinase-associated protein (GKAP), and postsynaptic density 95 (PSD95), all of which are biomarkers involved in neurodevelopmental processes closely related to glutamatergic pathways, have not previously been studied in patients with ADHD. The main purpose of this study was to evaluate the plasma levels of CDK5, MAP2, GKAP, and PSD95 in children with ADHD and investigate whether these markers have a role in the etiology of ADHD.

Methods

: Ninety-six children with ADHD between 6 and 15 years of age and 72 healthy controls were included in the study. Five milliliters of blood samples were taken from all participants. The samples were stored at -80°C until analyzed by the enzyme-linked immunosorbent assay method.

Results

: Statistically significantly lower CDK5 levels were observed in children with ADHD than in healthy controls (p = 0.037). The MAP2, GKAP, and PSD95 levels were found to be statistically significantly higher in the ADHD group than in healthy controls (p = 0.012, p = 0.009, and p = 0.024, respectively). According to binary regression analysis, CDK5 and MAP2 levels were found to be predictors of ADHD.

Conclusion

: In conclusion, we found that a close relationship existed between ADHD and glutamatergic pathways, and low levels of CDK5 and high levels of MAP2 and GKAP played a role in the etiopathogenesis of ADHD.

ADRAM is an experience-dependent long noncoding RNA that drives fear extinction through a direct interaction with the chaperone protein 14-3-3

Here, we used RNA capture-seq to identify a large population of lncRNAs that are expressed in the infralimbic prefrontal cortex of adult male mice in response to fear-related learning. Combining these data with cell-type-specific ATAC-seq on neurons that had been selectively activated by fear extinction learning, we find inducible 434 lncRNAs that are derived from enhancer regions in the vicinity of protein-coding genes. In particular, we discover an experience-induced lncRNA we call ADRAM (activity-dependent lncRNA associated with memory) that acts as both a scaffold and a combinatorial guide to recruit the brain-enriched chaperone protein 14-3-3 to the promoter of the memory-associated immediate-early gene Nr4a2 and is required fear extinction memory. This study expands the lexicon of experience-dependent lncRNA activity in the brain and highlights enhancer-derived RNAs (eRNAs) as key players in the epigenomic regulation of gene expression associated with the formation of fear extinction memory.

Maternal oxytocin administration modulates gene expression in the brains of perinatal mice

OBJECTIVES

Oxytocin (OXT) is widely used to facilitate labor. However, little is known about the effects of perinatal OXT exposure on the developing brain. We investigated the effects of maternal OXT administration on gene expression in perinatal mouse brains.

METHODS

Pregnant C57BL/6 mice were treated with saline or OXT at term (n=6-7/group). Dams and pups were euthanized on gestational day (GD) 18.5 after delivery by C-section. Another set of dams was treated with saline or OXT (n=6-7/group) and allowed to deliver naturally; pups were euthanized on postnatal day 9 (PND9). Perinatal/neonatal brain gene expression was determined using Illumina BeadChip Arrays and real time quantitative PCR. Differential gene expression analyses were performed. In addition, the effect of OXT on neurite outgrowth was assessed using PC12 cells.

RESULTS

Distinct and sex-specific gene expression patterns were identified in offspring brains following maternal OXT administration at term. The microarray data showed that female GD18.5 brains exhibited more differential changes in gene expression compared to male GD18.5 brains. Specifically, Cnot4 and Frmd4a were significantly reduced by OXT exposure in male and female GD18.5 brains, whereas Mtap1b, Srsf11, and Syn2 were significantly reduced only in female GD18.5 brains. No significant microarray differences were observed in PND9 brains. By quantitative PCR, OXT exposure reduced Oxtr expression in female and male brains on GD18.5 and PND9, respectively. PC12 cell differentiation assays revealed that OXT induced neurite outgrowth.

CONCLUSIONS

Prenatal OXT exposure induces sex-specific differential regulation of several nervous system-related genes and pathways with important neural functions in perinatal brains.

Beyond Neuronal Microtubule Stabilization: MAP6 and CRMPS, Two Converging Stories

The development and function of the central nervous system rely on the microtubule (MT) and actin cytoskeletons and their respective effectors. Although the structural role of the cytoskeleton has long been acknowledged in neuronal morphology and activity, it was recently recognized to play the role of a signaling platform. Following this recognition, research into Microtubule Associated Proteins (MAPs) diversified. Indeed, historically, structural MAPs—including MAP1B, MAP2, Tau, and MAP6 (also known as STOP);—were identified and described as MT-binding and -stabilizing proteins. Extensive data obtained over the last 20 years indicated that these structural MAPs could also contribute to a variety of other molecular roles. Among multi-role MAPs, MAP6 provides a striking example illustrating the diverse molecular and cellular properties of MAPs and showing how their functional versatility contributes to the central nervous system. In this review, in addition to MAP6’s effect on microtubules, we describe its impact on the actin cytoskeleton, on neuroreceptor homeostasis, and its involvement in signaling pathways governing neuron development and maturation. We also discuss its roles in synaptic plasticity, brain connectivity, and cognitive abilities, as well as the potential relationships between the integrated brain functions of MAP6 and its molecular activities. In parallel, the Collapsin Response Mediator Proteins (CRMPs) are presented as examples of how other proteins, not initially identified as MAPs, fall into the broader MAP family. These proteins bind MTs as well as exhibiting molecular and cellular properties very similar to MAP6. Finally, we briefly summarize the multiple similarities between other classical structural MAPs and MAP6 or CRMPs.In summary, this review revisits the molecular properties and the cellular and neuronal roles of the classical MAPs, broadening our definition of what constitutes a MAP.

[A differential peptidomics analysis of hippocampal tissue in a rat model of premature white matter injury]

OBJECTIVE

To observe differential peptidomics in the hippocampal tissue in a rat model of premature white matter injury, and to investigate the mechanism of premature white matter injury.

METHODS

Twenty neonatal Sprague-Dawley rats were randomly and equally divided into a control group and a model group. Rats in the model group underwent permanent ligation of the right common carotid artery 2 days after birth, followed by 2 hours of hypoxia. For rats in the control group, the right common carotid artery was isolated, but without ligation and hypoxia. Brain tissue samples were collected from the two groups, and hippocampal tissue was isolated. Liquid chromatography-tandem mass spectrometry combined with tandem mass spectrometry was used for peptidomic profiling of hippocampal tissue, and the differentially expressed peptides between the two groups were subjected to bioinformatics analysis to assess their possible roles in neural development and function.

RESULTS

A total of 4164 peptides were identified and quantified, and 262 of them were differentially expressed (absolute fold change ≥2.5), including 164 upregulated peptides and 98 downregulated peptides. The numbers of differentially expressed peptides of the precursor proteins ELN, PCLO, MYO15a, MAP4, and MAP1b were the most, and may play significant roles in the pathogenesis of premature white matter injury. CDK5 signaling pathway in the hippocampus was activated in the rat model of premature white matter injury.

CONCLUSIONS

The differentially expressed peptides related to precursor proteins such as MAP1b may be key bioactive peptides involved in neural development and function in premature white matter injury, and activation of the CDK5 signaling pathway may be associated with premature white matter injury.

Peptidomic analysis of hippocampal tissue for explore leptin neuroprotective effect on the preterm ischemia-hypoxia brain damage model rats

The most common injury of preterm infants is periventricular leukomalacia (PVL) and to date there is still no safe and effective treatment. In our previous studies, leptin has been found to have neuroprotective effects on the preterm ischemia-hypoxia brain damage model rats in animal behavior. To gain insight into the neuroprotective mechanisms of leptin on preterm brain damage model rats, we constructed a comparative peptidomic profiling of hippocampal tissue between leptin-treated after model and preterm ischemia-hypoxia brain damage model rats using a stable isobaric labeling strategy involving tandem mass tag reagents, followed by nano liquid chromatography tandem mass spectrometry. We identified and quantified 4164 peptides, 238 of which were differential expressed in hippocampal tissue in the two groups. A total of 150 peptides were up regulated and 88 peptides were down regulated. These peptides were imported into the Ingenuity Pathway Analysis (IPA) and identified putative roles in nervous system development, function and diseases. We concluded that the preterm ischemia-hypoxia brain damage model with leptin treatment induced peptides changes in hippocampus, and these peptides, especially for the peptides associated "microtubule-associated protein 1b (MAP1b), Elastin (Eln), Piccolo presynaptic cytomatrix protein (Pclo), Zinc finger homeobox 3(Zfhx3), Alpha-kinase 3(Alpk3) and Myosin XVA(Myo15a) ", could be candidate bio-active peptides and participate in neuroprotection of leptin. These may advance our current understanding of the mechanism of leptin's neuroprotective effect on preterm brain damage and may be involved in the etiology of preterm brain damage. Meanwhile, we found that repression of ILK signaling pathway plays a significant role in neuroprotection of leptin. A better understanding of the role of ILK signaling pathway in neuroprotective mechanisms will help scientists and researchers to develop selective, safe and efficacious drug for therapy against human nervous system disorders.

Attention-Deficit/Hyperactivity Disorder: Focus upon Aberrant N-Methyl-D-Aspartate Receptors Systems

Attention-deficit/hyperactivity disorder (ADHD) pathophysiology persists in an obscure manner with complex interactions between symptoms, staging, interventions, genes, and environments. Only on the basis of increasing incidence of the disorder, the need for understanding is greater than ever. The notion of an imbalance between central inhibitory/excitatory neurotransmitters is considered to exert an essential role. In this chapter, we first review how the default mode network functions and dysfunction in individuals diagnosed with ADHD. We also present and briefly review some of the animal models used to examine the neurobiological aspects of ADHD. There is much evidence indicating that compounds/interventions that antagonize/block glutamic acid receptors and/or block the glutamate signal during the "brain growth spurt" or in the adult animal may induce functional and biomarker deficits. Additionally, we present evidence suggesting that animals treated with glutamate blockers at the period of the "brain growth spurt" fail to perform the exploratory activity, observed invariably with control mice, that is associated with introduction to a novel environment (the test cages). Later, when the control animals show less locomotor and rearing activity, i.e., interest in the test cages, the MK-801, ketamine and ethanol treated mice showed successively greater levels of locomotion and rearing (interest), i.e., they fail to "habituate" effectively, implying a cognitive dysfunction. These disturbances of glutamate signaling during a critical period of brain development may contribute to the ADHD pathophysiology. As a final addition, we have briefly identified new research venues in the interaction between ADHD, molecular studies, and personality research.