Epigenetic mechanisms in the placenta related to infant neurodevelopment.

As the 'third brain' the placenta links the developing fetal brain and the maternal brain enabling study of epigenetic process in placental genes that affect infant neurodevelopment. We described the characteristics and findings of the 17 studies on epigenetic processes in placental genes and human infant neurobehavior. Studies showed consistent findings in the same cohort of term healthy infants across epigenetic processes (DNA methylation, genome wide, gene and miRNA expression) genomic region (single and multiple genes, imprinted genes and miRNAs) using candidate gene and genome wide approaches and across biobehavioral systems (neurobehavior, cry acoustics and neuroendocrine). Despite limitations, studies support future work on molecular processes in placental genes related to neurodevelopmental trajectories including implications for intervention.

Early lethality and neuronal proteinopathy in mice expressing cytoplasm-targeted FUS that lacks the RNA recognition motif.

Mutations to the RNA binding protein, fused in sarcoma (FUS) occur in ∼5% of familial ALS and FUS-positive cytoplasmic inclusions are commonly observed in these patients. Altered RNA metabolism is increasingly implicated in ALS, yet it is not understood how the specificity with which FUS interacts with RNA in the cytoplasm can affect its aggregation in vivo. To further understand this, we expressed, in mice, a form of FUS (FUS ΔRRMcyt) that lacked the RNA recognition motif (RRM), thought to impart specificity to FUS-RNA interactions, and carried an ALS-associated point mutation, R522G, retaining the protein in the cytoplasm. Here we report the phenotype and results of histological assessment of the brain of transgenic mice expressing this isoform of FUS. Results demonstrated that neuronal expression of FUS ΔRRMcyt caused early lethality often preceded by severe tremor. Large FUS-positive cytoplasmic inclusions were found in many brain neurons; however, neither neuronal loss nor neuroinflammatory response was observed. In conclusion, the extensive FUS proteinopathy and severe phenotype of these mice suggests that affecting the interactions of FUS with RNA in vivo may augment its aggregation in the neuronal cytoplasm and the severity of disease processes.

Gene expression changes of Caenorhabditis elegans larvae during molting and sleep-like lethargus.

During their development, Caenorhabditis elegans larvae go through four developmental stages. At the end of each larval stage, nematodes molt. They synthesize a new cuticle and shed the old cuticle. During the molt, larvae display a sleep-like behavior that is called lethargus. We wanted to determine how gene expression changes during the C. elegans molting cycle. We performed transcriptional profiling of C. elegans by selecting larvae displaying either sleep-like behavior during the molt or wake behavior during the intermolt to identify genes that oscillate with the molting-cycle. We found that expression changed during the molt and we identified 520 genes that oscillated with the molting cycle. 138 of these genes were not previously reported to oscillate. The majority of genes that had oscillating expression levels appear to be involved in molting, indicating that the majority of transcriptional changes serve to resynthesize the cuticle. Identification of genes that control sleep-like behavior during lethargus is difficult but may be possible by looking at genes that are expressed in neurons. 22 of the oscillating genes were expressed in neurons. One of these genes, the dopamine transporter gene dat-1, was previously shown in mammals and in C. elegans to control sleep. Taken together, we provide a dataset of genes that oscillate with the molting and sleep-wake cycle, which will be useful to investigate molting and possibly also sleep-like behavior during lethargus.

Autism traits in children and adolescents with Cornelia de Lange syndrome.

Cornelia de Lange syndrome (CdLS) is a cohesinopathy causing delayed growth and limb deficits. Individuals with CdLS have mild to profound intellectual disability and autistic features. This study characterizes the behavioral phenotype of children with CdLS, focusing on autistic features, maladaptive behaviors, and impact of age. Children with CdLS (5-18 years) were administered normed instruments to characterize autism features (Childhood Autism Rating Scale, CARS), maladaptive behaviors (Aberrant Behavior Checklist), and adaptive skills (Vineland Adaptive Behaviors Scales). CdLS features and severity were rated with Diagnostic Criteria for CdLS. Forty-one children with CdLS (23 females, 18 males) were classified as having "no autism" (n = 7; 17.1%), "mild autism" (n = 17; 41.4%), and "severe autism" (n = 17; 41.4%), using CARS scores. Characteristic items were abnormal emotional response, stereotypies, odd object use, rigidity, lack of verbal communication, and low intellectual functioning. Verbal communication deficits and repetitive behaviors were higher compared to sensory, social cognition, and behavior abnormalities (P ≤ 0.0001). Maladaptive behaviors associated with autism traits were stereotypies (P = 0.003), hyperactivity (P = 0.01), and lethargy (P = 0.03). Activities of daily living were significantly affected; socialization adaptive skills were a relative strength. However, with advancing age, both socialization (P < 0.0001) and communication (P = 0.001) domains declined significantly. CdLS is characterized by autistic features, notably excessive repetitive behaviors and expressive language deficits. While other adaptive skills are impacted, socialization adaptive skills are less affected. Advancing age can worsen communication and socialization deficits relative to neurotypical peers.

Elevated plasma citrulline: look for dihydrolipoamide dehydrogenase deficiency.

The E3 subunit of the pyruvate dehydrogenase complex (dihydrolipoamide dehydrogenase/dihydrolipoyl dehydrogenase/DLD/lipoamide dehydrogenase/LAD), is a mitochondrial matrix enzyme and also a part of the branched-chain ketoacid dehydrogenase and alpha-ketoglutarate dehydrogenase complexes. DLD deficiency (MIM #246900), is relatively frequent in the Ashkenazi Jewish population but occurs in other populations as well. Early diagnosis is important to prevent episodes of metabolic decompensation, liver failure, and encephalopathy. The clinical presentations are varied and may include Reye-like syndrome, hepatic failure, myopathy, and myoglobinuria. Laboratory markers, such as elevated urinary alpha-ketoglutarate, blood pyruvate, lactate, and ammonia, are mostly nonspecific and not always present, making the diagnosis difficult. Since we observed elevated plasma citrulline levels in a number of confirmed cases, we retrospectively examined the value of citrulline as a biochemical marker for DLD deficiency. Data was gathered from the files of 17 pediatric patients with DLD deficiency, confirmed by enzymatic and genetic analysis. The control group included 19 patients in whom urea cycle defects were ruled out but DLD deficiency was suspected. Seven of the DLD-deficient patients presented with elevated plasma citrulline levels (median value 205 µM, range 59-282 µM) (normal range 1-45 µM) while none in the control patient group. In five patients, elevated citrulline was associated with elevated plasma glutamine and metabolic acidosis. Interestingly, elevated plasma citrulline was associated with the common G229C mutation. In conclusion, we suggest that elevated plasma citrulline in the absence of urea cycle defects warrants an investigation for DLD deficiency.

Analysis of NPR-1 reveals a circuit mechanism for behavioral quiescence in C. elegans.

Animals undergo periods of behavioral quiescence and arousal in response to environmental, circadian, or developmental cues. During larval molts, C. elegans undergoes a period of profound behavioral quiescence termed lethargus. Locomotion quiescence during lethargus was abolished in mutants lacking a neuropeptide receptor (NPR-1) and was reduced in mutants lacking NPR-1 ligands (FLP-18 and FLP-21). Wild-type strains are polymorphic for the npr-1 gene, and their lethargus behavior varies correspondingly. Locomotion quiescence and arousal were mediated by decreased and increased secretion of an arousal neuropeptide (PDF-1) from central neurons. PDF receptors (PDFR-1) expressed in peripheral mechanosensory neurons enhanced touch-evoked calcium transients. Thus, a central circuit stimulates arousal from lethargus by enhancing the sensitivity of peripheral mechanosensory neurons in the body. These results define a circuit mechanism controlling a developmentally programmed form of quiescence.

Glucagon receptor is required for long-term survival: a natural history study of the Mahvash disease in a murine model.

BACKGROUND AND AIM: We have described a novel Mahvash disease of hyperglucagonemia and pancreatic neuroendocrine tumors (PNETs) associated with an inactivating glucagon receptor mutation, and identified the glucagon receptor-deficient (Gcgr(-/-)) mice as its murine model. We aim to elucidate the natural history of the rare Mahvash disease by long-term observation of the Gcgr(-/-) mice. MATERIALS AND METHOD: Wild type (WT) (n=52), heterozygous (n=127), and Gcgr(-/-) (n=56) mice living under standard vivarium conditions were observed without specific treatments over 22 months. Autopsy was performed on dead animals. RESULTS: The WT and heterozygous mice did not exhibit any measurable differences. The Gcgr(-/-) mice became progressively lethargic and cachexic after 12 months. Random glucose levels were stable in WT and heterozygous mice but decreased with age in the Gcgr(-/-) mice. At the end of observation, 28/56 Gcgr(-/-), 7/52 WT, and 24/127 heterozygous mice died. The survival curve of Gcgr(-/-) mice began to separate from those of WT and heterozygous mice at 12 months and the survival difference widened with age. At 18 months, survival probability was 17% for Gcgr(-/-) mice but 77% for WT and 81% for heterozygous mice. Autopsy revealed numerous PNETs up to 15 mm in diameter in most well-preserved Gcgr(-/-) pancreata (17/20) but none in WT or heterozygous ones. Four Gcgr(-/-) mice developed liver or subcutaneous metastasis. CONCLUSION: The untreated Mahvash disease may cause cachexia, severe hypoglycemia, and early death. Patients with Mahvash disease need to undergo life-long surveillance for PNETs. Functional glucagon receptor is thus required for long-term survival.

TAK1 in brain endothelial cells mediates fever and lethargy.

Systemic inflammation affects the brain, resulting in fever, anorexia, lethargy, and activation of the hypothalamus-pituitary-adrenal axis. How peripheral inflammatory signals reach the brain is still a matter of debate. One possibility is that, in response to inflammatory stimuli, brain endothelial cells in proximity to the thermoregulatory centers produce cyclooxygenase 2 (COX-2) and release prostaglandin E2, causing fever and sickness behavior. We show that expression of the MAP kinase kinase kinase TAK1 in brain endothelial cells is needed for interleukin 1ß (IL-1ß)-induced COX-2 production. Exploiting the selective expression of the thyroxine transporter Slco1c1 in brain endothelial cells, we generated a mouse line allowing inducible deletion of Tak1 specifically in brain endothelium. Mice lacking the Tak1 gene in brain endothelial cells showed a blunted fever response and reduced lethargy upon intravenous injection of the endogenous pyrogen IL-1ß. In conclusion, we demonstrate that TAK1 in brain endothelial cells induces COX-2, most likely by activating p38 MAPK and c-Jun, and is necessary for fever and sickness behavior.

Epidermal growth factor signaling induces behavioral quiescence in Caenorhabditis elegans.

The epidermal growth factor receptor (EGFR)/ErbB receptor tyrosine kinases regulate several aspects of development, including the development of the mammalian nervous system. ErbB signaling also has physiological effects on neuronal function, with influences on synaptic plasticity and daily cycles of activity. However, little is known about the effectors of EGFR activation in neurons. Here we show that EGF signaling has a nondevelopmental effect on behavior in Caenorhabditis elegans. Ectopic expression of the EGF-like ligand LIN-3 at any stage induces a reversible cessation of feeding and locomotion. These effects are mediated by neuronal EGFR (also called LET-23) and phospholipase C-gamma (PLC-gamma), diacylglycerol-binding proteins, and regulators of synaptic vesicle release. Activation of EGFR within a single neuron, ALA, is sufficient to induce a quiescent state. This pathway modulates the cessation of pharyngeal pumping and locomotion that normally occurs during the lethargus period that precedes larval molting. Our results reveal an evolutionarily conserved role for EGF signaling in the regulation of behavioral quiescence.

Redundancy of Cav2.1 channel accessory subunits in transmitter release at the mouse neuromuscular junction.

Ca(v)2.1 (P/Q-type) channels possess a voltage-sensitive pore-forming alpha(1) subunit that can associate with the accessory subunits alpha(2)delta, beta and gamma. The primary role of Ca(v)2.1 channels is to mediate transmitter release from nerve terminals both in the central and peripheral nervous system. Whole-cell voltage-clamp studies in in vitro expression systems have indicated that accessory channel subunits can have diverse modulatory effects on membrane expression and biophysical properties of Ca(v)2.1 channels. However, there is only limited knowledge on whether similar modulation also occurs in the specific presynaptic environment in vivo and, hence, whether accessory subunits influence neurotransmitter release. Ducky, lethargic and stargazer are mutant mice that lack functional alpha(2)delta-2, beta(4) and gamma(2) accessory Ca(v) channel subunits, respectively. The neuromuscular junction (NMJ) is a peripheral synapse, where transmitter release is governed exclusively by Ca(v)2.1 channels, and which can be characterized electrophysiologically with relative experimental ease. In order to investigate a possible synaptic influence of accessory subunits in detail, we electrophysiologically measured acetylcholine (ACh) release at NMJs of these three mutants. Surprisingly, we did not find any changes compared to wild-type littermates, other than a small reduction (25%) of evoked ACh release at ducky NMJs. This effect is most likely due to the approximately 40% reduced synapse size, associated with the reduced size of ducky mice, rather than resulting directly from reduced Ca(v)2.1 channel function due to alpha(2)delta-2 absence. We conclude that alpha(2)delta-2, beta(4), and gamma(2) accessory subunits are redundant for the transmitter release-mediating function of presynaptic Ca(v)2.1 channels at the mouse NMJ.