Perinatal asphyxia alters neuregulin-1 and COMT gene expression in the medial prefrontal cortex in rats

Epidemiological studies suggest that perinatal complications, particularly hypoxia-related ones, increase the risk of schizophrenia. Recent genetic studies of the disorder have identified several putative susceptibility genes, some of which are known to be regulated by hypoxia. It can be postulated therefore that birth complications that cause hypoxia in the fetal brain may be associated with a dysregulation in the expression of some of the schizophrenia candidate genes. To test this, we used an animal model of perinatal asphyxia, in which rat pups were exposed to 15 min of intrauterine anoxia during Caesarean section birth, and examined the expression of mRNA of five of the putative susceptibility genes (NRG1, ErbB4, AKT1, COMT and BDNF) by real-time quantitative PCR in the medial prefrontal cortex (mPFC) and the hippocampus at 6 and 12 weeks after birth. The expression of NRG1 mRNA was significantly decreased in the mPFC, but not in the hippocampus, at 6 and 12 weeks after birth. In addition, a significant increase in COMT mRNA expression was observed in the mPFC at 12 weeks. The alteration in mRNA levels of NRG1 and COMT was not associated with a change in their protein levels. These results suggest that perinatal asphyxia may lead to disturbances in the PFC, which in turn may exert a long-lasting influence on the expression of specific genes, such as NRG1 and COMT. Our results also suggest that translational interruption may occur in this model of perinatal asphyxia.

Aging effect on plasma metabolites and hormones concentrations in riding horses

Age effects on plasma metabolites, hormone concentrations, and enzyme activities related to energy metabolism were investigated in 20 riding horses. Animals were divided into two groups: young (3-8 years) and aged (11-18 years). They were clinically healthy, and not obese. Plasma adiponectin (ADN) concentrations in aged horses were significantly lower than those in young horses (mean±SE, 6.5±1.3 µg mL-1 vs, 10.9±1.7 µg mL-1, Mann-Whitney U test, respectively; P=0.0233). Plasma non-esterified fatty acid levels and Insulin and malondialdehyde concentrations in aged group tended to increase compared to those in young group although there were not significant differences statistically. In aged group, malate dehydrogenase/lactate dehydrogenase (M/L) ratio, which is considered an energy metabolic indicator, did not change significantly compared to that in young group. Present data suggest that aging may negatively affect nutrition metabolism, but not induce remarkable changes in M/L ratio in riding horses.

Aging effect on plasma metabolites and hormones concentrations in riding horses

Age effects on plasma metabolites, hormone concentrations, and enzyme activities related to energy metabolism were investigated in 20 riding horses. Animals were divided into two groups: Young (3-8 years) and aged (11-18 years). They were clinically healthy, and not obese. Plasma adiponectin (ADN) concentrations in aged horses were significantly lower than those in young horses (mean±SE, 6.5±1.3 µg mL(-1) vs, 10.9±1.7 µg mL(-1), Mann-Whitney U test, respectively; P=0.0233). Plasma non-esterified fatty acid levels and Insulin and malondialdehyde concentrations in aged group tended to increase compared to those in young group although there were not significant differences statistically. In aged group, malate dehydrogenase/lactate dehydrogenase (M/L) ratio, which is considered an energy metabolic indicator, did not change significantly compared to that in young group. Present data suggest that aging may negatively affect nutrition metabolism, but not induce remarkable changes in M/L ratio in riding horses.

Exon resequencing of H3K9 methyltransferase complex genes, EHMT1, EHTM2 and WIZ, in Japanese autism subjects

Background

Histone H3 methylation at lysine 9 (H3K9) is a conserved epigenetic signal, mediating heterochromatin formation by trimethylation, and transcriptional silencing by dimethylation. Defective GLP (Ehmt1) and G9a (Ehmt2) histone lysine methyltransferases, involved in mono and dimethylation of H3K9, confer autistic phenotypes and behavioral abnormalities in animal models. Moreover, EHMT1 loss of function results in Kleefstra syndrome, characterized by severe intellectual disability, developmental delays and psychiatric disorders. We examined the possible role of histone methyltransferases in the etiology of autism spectrum disorders (ASD) and suggest that rare functional variants in these genes that regulate H3K9 methylation may be associated with ASD.

Methods

Since G9a-GLP-Wiz forms a heteromeric methyltransferase complex, all the protein-coding regions and exon/intron boundaries of EHMT1, EHMT2 and WIZ were sequenced in Japanese ASD subjects. The detected variants were prioritized based on novelty and functionality. The expression levels of these genes were tested in blood cells and postmortem brain samples from ASD and control subjects. Expression of EHMT1 and EHMT2 isoforms were determined by digital PCR.

Results

We identified six nonsynonymous variants: three in EHMT1, two in EHMT2 and one in WIZ. Two variants, the EHMT1 ankyrin repeat domain (Lys968Arg) and EHMT2 SET domain (Thr961Ile) variants were present exclusively in cases, but showed no statistically significant association with ASD. The EHMT2 transcript expression was significantly elevated in the peripheral blood cells of ASD when compared with control samples; but not for EHMT1 and WIZ. Gene expression levels of EHMT1, EHMT2 and WIZ in Brodmann area (BA) 9, BA21, BA40 and the dorsal raphe nucleus (DoRN) regions from postmortem brain samples showed no significant changes between ASD and control subjects. Nor did expression levels of EHMT1 and EHMT2 isoforms in the prefrontal cortex differ significantly between ASD and control groups.

Conclusions

We identified two novel rare missense variants in the EHMT1 and EHMT2 genes of ASD patients. We surmise that these variants alone may not be sufficient to exert a significant effect on ASD pathogenesis. The elevated expression of EHMT2 in the peripheral blood cells may support the notion of a restrictive chromatin state in ASD, similar to schizophrenia.

Electronic supplementary material

The online version of this article (doi:10.1186/2040-2392-5-49) contains supplementary material, which is available to authorized users.

Zinc finger protein 804A (ZNF804A) and verbal deficits in individuals with autism

BACKGROUND

In a genome-wide association study of autism, zinc finger protein 804A (ZNF804A) single nucleotide polymorphisms (SNPs) were found to be nominally associated in verbally deficient individuals with autism. Zinc finger protein 804A copy number variations (CNVs) have also been observed in individuals with autism. In addition, ZNF804A is known to be involved in theory of mind (ToM) tasks, and ToM deficits are deemed responsible for the communication and social challenges faced by individuals with autism. We hypothesized that ZNF804A could be a risk gene for autism.

METHODS

We examined the genetic association and CNVs of ZNF804A in 841 families in which 1 or more members had autism. We compared the expression of ZNF804A in the postmortem brains of individuals with autism (n = 8) and controls (n = 13). We also assessed in vitro the effect of ZNF804A silencing on the expression of several genes known to be involved in verbal efficiency and social cognition.

RESULTS

We found that rs7603001 was nominally associated with autism (p = 0.018). The association was stronger (p = 0.008) in the families of individuals with autism who were verbally deficient (n = 761 families). We observed ZNF804A CNVs in 7 verbally deficient boys with autism. In ZNF804A knockdown cells, the expression of synaptosomal-associated protein, 25kDa (SNAP25) was reduced compared with controls (p = 0.009). The expression of ZNF804A (p = 0.009) and SNAP25 (p = 0.009) were reduced in the anterior cingulate gyrus (ACG) of individuals with autism. There was a strong positive correlation between the expression of ZNF804A and SNAP25 in the ACG (p < 0.001).

LIMITATIONS

Study limitations include our small sample size of postmortem brains.

CONCLUSION

Our results suggest that ZNF804A could be a potential candidate gene mediating the intermediate phenotypes associated with verbal traits in individuals with autism.

Serum microRNA profiles in children with autism

Background

As regulators of gene expression, microRNAs (miRNAs) play a key role in the transcriptional networks of the developing human brain. Circulating miRNAs in the serum and plasma are remarkably stable and are suggested to have promise as noninvasive biomarkers for neurological and neurodevelopmental disorders. We examined the serum expression profiles of neurologically relevant miRNAs in autism spectrum disorder (ASD), a complex neurodevelopmental disorder characterized by multiple deficits in communication, social interaction and behavior.

Methods

Total RNA, including miRNA, was extracted from the serum samples of 55 individuals with ASD and 55 age- and sex-matched control subjects, and the mature miRNAs were selectively converted into cDNA. Initially, the expression of 125 mature miRNAs was compared between pooled control and ASD samples. The differential expression of 14 miRNAs was further validated by SYBR Green quantitative PCR of individual samples. Receiver-operating characteristic (ROC) analysis was used to evaluate the sensitivity and specificity of miRNAs. The target genes and pathways of miRNAs were predicted using DIANA mirPath software.

Results

Thirteen miRNAs were differentially expressed in ASD individuals compared to the controls. MiR-151a-3p, miR-181b-5p, miR-320a, miR-328, miR-433, miR-489, miR-572, and miR-663a were downregulated, while miR-101-3p, miR-106b-5p, miR-130a-3p, miR-195-5p, and miR-19b-3p were upregulated. Five miRNAs showed good predictive power for distinguishing individuals with ASD. The target genes of these miRNAs were enriched in several crucial neurological pathways.

Conclusions

This is the first study of serum miRNAs in ASD individuals. The results suggest that a set of serum miRNAs might serve as a possible noninvasive biomarker for ASD.

Functional characterization of FABP3, 5 and 7 gene variants identified in schizophrenia and autism spectrum disorder and mouse behavioral studies

Disturbances of lipid metabolism have been implicated in psychiatric illnesses. We previously reported an association between the gene for fatty acid binding protein 7 (FABP7) and schizophrenia. Furthermore, we identified and reported several rare non-synonymous polymorphisms of the brain-expressed genes FABP3, FABP5 and FABP7 from schizophrenia and autism spectrum disorder (ASD), diseases known to part share genetic architecture. Here, we conducted further studies to better understand the contribution these genes make to the pathogenesis of schizophrenia and ASD. In postmortem brains, we detected altered mRNA expression levels of FABP5 in schizophrenia, and of FABP7 in ASD and altered FABP5 in peripheral lymphocytes. Using a patient cohort, comprehensive mutation screening identified six missense and two frameshift variants from the three FABP genes. The two frameshift proteins, FABP3 E132fs and FABP7 N80fs, formed cellular aggregates and were unstable when expressed in cultured cells. The four missense mutants with predicted possible damaging outcomes showed no changes in intracellular localization. Examining ligand binding properties, FABP7 S86G and FABP7 V126L lost their preference for docosahexaenoic acid to linoleic acid. Finally, mice deficient in Fabp3, Fabp5 and Fabp7 were evaluated in a systematic behavioral test battery. The Fabp3 knockout (KO) mice showed decreased social memory and novelty seeking, and Fabp7 KO mice displayed hyperactive and anxiety-related phenotypes, while Fabp5 KO mice showed no apparent phenotypes. In conclusion, disturbances in brain-expressed FABPs could represent an underlying disease mechanism in a proportion of schizophrenia and ASD sufferers.

Interaction of hydrophobic components in female urine before and after childbirth with P-glycoprotein in vitro

The first urine in the morning (total 15 samples) and whole day urine (total 4 days, 17 samples) were collected from a young healthy woman during the pregnancy and lactation period, to examine the possible interactions of urine components (methanol extracts) with P-glycoprotein (P-gp) and multidrug resistance-associated proteins (MRPs). The interaction was evaluated by measuring the intracellular accumulation of rhodamine123, a P-gp substrate, in LLC-GA5-COL150 cells, or calcein, an MRP substrate, in Caco-2 cells in the absence and presence of urine components. Four first urine samples out of 12 collected before childbirth and one sample out of three collected after childbirth suppressed P-gp function significantly. The effect of pregnancy and lactation on P-gp inhibitory potencies of urine components was not observed. The whole day urine samples showed a clear circadian rhythm, in which three first urine samples in the morning out of four showed greater P-gp inhibitory potencies than other daytime samples. Interaction of urine components with MRPs was not detected. In conclusion, the concentration of endogenous P-gp inhibitor(s) was higher in the first urine in the morning, showing a clear circadian rhythm. Normal pregnancy and lactation appeared not to significantly affect the P-gp inhibitory potencies of urine components.

N-ethylmaleimide-sensitive factor interacts with the serotonin transporter and modulates its trafficking: implications for pathophysiology in autism

Background

Changes in serotonin transporter (SERT) function have been implicated in autism. SERT function is influenced by the number of transporter molecules present at the cell surface, which is regulated by various cellular mechanisms including interactions with other proteins. Thus, we searched for novel SERT-binding proteins and investigated whether the expression of one such protein was affected in subjects with autism.

Methods

Novel SERT-binding proteins were examined by a pull-down system. Alterations of SERT function and membrane expression upon knockdown of the novel SERT-binding protein were studied in HEK293-hSERT cells. Endogenous interaction of SERT with the protein was evaluated in mouse brains. Alterations in the mRNA expression of SERT (SLC6A4) and the SERT-binding protein in the post-mortem brains and the lymphocytes of autism patients were compared to nonclinical controls.

Results

N-ethylmaleimide-sensitive factor (NSF) was identified as a novel SERT-binding protein. NSF was co-localized with SERT at the plasma membrane, and NSF knockdown resulted in decreased SERT expression at the cell membranes and decreased SERT uptake function. NSF was endogenously co-localized with SERT and interacted with SERT. While SLC6A4 expression was not significantly changed, NSF expression tended to be reduced in post-mortem brains, and was significantly reduced in lymphocytes of autistic subjects, which correlated with the severity of the clinical symptoms.

Conclusions

These data clearly show that NSF interacts with SERT under physiological conditions and is required for SERT membrane trafficking and uptake function. A possible role for NSF in the pathophysiology of autism through modulation of SERT trafficking, is suggested.

Abstract P3-01-01: Targeting glutamine metabolism in breast cancer for therapy

Metabolic reprogramming of cancer cells is observed in different types of tumors including breast. Oncogenic signals aid changes in metabolism that provide selective advantage to the cancer cells to meet their energy requirements to accomplish rapid proliferation. The increased dependence on the glycolytic pathway for energy called the “Warburg effect” was reported by Otto Warburg several decades ago. Our recent understanding of cancer metabolism has thrown light on alternative energy sources, especially glutamine and other branched chain amino acids. The role of glutamine in breast cancer cell growth has not yet been studied extensively.

In this study we found that a number of breast cancer cell lines, especially those negative for ER, PR, HER2, display a high dependence on glutamine for their survival and growth. Interestingly, most of these glutamine-dependent cell lines express high levels of c-myc protein. Consistent with their growth dependency on glutamine, transaminases responsible for entry of glutamine into the tricarboxylic acid cycle are transcriptionally up regulated under low glutamine conditions. Consequently, growth of these cancer cell lines was found to be specifically inhibited by the transaminase inhibitor, amino oxyacetate (AOA). Moreover, the AOA mediated cytotoxic effect was partially c-myc dependent. Through 1H-NMR studies of AOA-treated cells we show that in addition to glutamine, AOA treatment decreases the aspartate and alanine content in the cells. In line with these findings, exogenous supplementation with aspartate partially rescued the cells from the growth inhibitory effects of AOA. Flow cytometry analysis showed that AOA causes cell cycle arrest in the S phase. AOA also had significant inhibitory effect on in vivo growth of rapidly growing SUM 149 and SUM159 xenografts in immunodeficient mice. When combined with chemotherapeutic agents, doxorubicin and carboplatin, AOA inhibited growth of MDA-MB-231 xenograft tumors more effectively than AOA alone. Lastly we present evidence that the cytotoxic effect of AOA is mediated through activation of the ER stress pathway, combined with depletion of key amino acids and likely, a reduction in the nucleoside pool in the cells. Our preclinical studies, both in vitro and in vivo, combined with development of intermediate markers of response, provide a strong rationale for testing AOA for therapy in Phase 0 clinical trials.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-01-01.

Cosmic-ray positron energy spectrum measured by PAMELA

Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.

Reliability and validity of autism diagnostic interview-revised, Japanese version

To examine the inter-rater reliability of Autism Diagnostic Interview-Revised, Japanese Version (ADI-R-JV), the authors recruited 51 individuals aged 3-19 years, interviewed by two independent raters. Subsequently, to assess the discriminant and diagnostic validity of ADI-R-JV, the authors investigated 317 individuals aged 2-19 years, who were divided into three diagnostic groups as follows: autistic disorder (AD), pervasive developmental disorder not otherwise specified, and other psychiatric diagnosis or no diagnosis, according to the consensus clinical diagnosis. As regards inter-rater reliability, intraclass correlation coefficients of greater than 0.80 were obtained for all three domains of ADI-R-JV. As regards discriminant validity, the mean scores of the three domains was significantly higher in individuals with AD than in those of other diagnostic groups. As regards diagnostic validity, sensitivity and specificity for correctly diagnosing AD were 0.92 and 0.89, respectively, but sensitivity was 0.55 for individuals younger than 5 years. Specificity was consistently high regardless of age and intelligence. ADI-R-JV was shown to be a reliable tool, and has sufficient discriminant validity and satisfactory diagnostic validity for correctly diagnosing AD, although the diagnostic validity appeared to be compromised with respect to the diagnosis of younger individuals.

Serum levels of soluble platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 are decreased in subjects with autism spectrum disorder

BACKGROUND

Adhesion molecules, such as platelet-endothelial adhesion molecule-1 (PECAM-1), platelet selectin (P-selectin), endothelial selectin (E-selectin), intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), are localized on the membranes of activated platelets and leukocytes and on the vascular endothelium. Recently, we measured serum levels of soluble (s) forms of adhesion molecules in adults,18 to 26 years old, with autism spectrum disorder (ASD) and observed low levels of sPECAM-1 and sP-selectin. A subsequent study showed a similar result in children two to four years old with ASD. However, information about school age (five to seventeen years old) ASD subjects is required to determine whether adhesion molecules are also reduced in individuals with ASD in this age range.

FINDINGS

Twenty-two subjects with high-functioning ASD and 29 healthy age-matched controls were recruited. ELISA was used for sPECAM-1, and a suspension array system was used for sP-selectin, sE-selectin, sICAM-1 and sVCAM-1 measurements. We found that serum levels of sPECAM-1 (U = 91.0, P<0.0001 by Mann-Whitney U test) and sVCAM-1 (U = 168.0, P = 0.0042) were significantly lower in ASD subjects than in controls. Subsequently, we examined the correlations between serum levels of either sPECAM-1 or sVCAM-1 and clinical variables including Autism Diagnostic Interview - Revised subscores and our previous cytokine profile data from the same ASD subjects. However, we did not find any significant correlations between them.

CONCLUSIONS

The present results, taken together with previous results, suggest that sPECAM-1 may play a role in the generation and development of ASD, beginning in childhood and lasting until adulthood.

Intratumoral concentration of estrogens and clinicopathological changes in ductal carcinoma in situ following aromatase inhibitor letrozole treatment

Background:

Estrogens have important roles in ductal carcinoma in situ (DCIS) of the breast. However, the significance of presurgical aromatase inhibitor treatment remains unclear. Therefore, we examined intratumoral concentration of estrogens and changes of clinicopathological factors in DCIS after letrozole treatment.

Methods:

Ten cases of postmenopausal oestrogen receptor (ER)-positive DCIS were examined. They received oral letrozole before the surgery, and the tumour size was evaluated by ultrasonography. Surgical specimens and corresponding biopsy samples were used for immunohistochemistry. Snap-frozen specimens were also available in a subset of cases, and used for hormone assays and microarray analysis.

Results:

Intratumoral oestrogen levels were significantly lower in DCIS treated with letrozole compared with that in those without the therapy. A great majority of oestrogen-induced genes showed low expression levels in DCIS treated with letrozole by microarray analysis. Moreover, letrozole treatment reduced the greatest dimension of DCIS, and significantly decreased Ki-67 and progesterone receptor immunoreactivity in DCIS tissues.

Conclusion:

These results suggest that estrogens are mainly produced by aromatase in DCIS tissues, and aromatase inhibitors potently inhibit oestrogen actions in postmenopausal ER-positive DCIS through rapid deprivation of intratumoral estrogens.

The role of trigeminal nasal TRPM8-expressing afferent neurons in the antitussive effects of menthol

The cold-sensitive cation channel TRPM8 is a target for menthol, which is used routinely as a cough suppressant and as an additive to tobacco and food products. Given that cold temperatures and menthol activate neurons through gating of TRPM8, it is unclear how menthol actively suppresses cough. In this study we describe the antitussive effects of (-)-menthol in conscious and anesthetized guinea pigs. In anesthetized guinea pigs, cough evoked by citric acid applied topically to the tracheal mucosa was suppressed by menthol only when it was selectively administered as vapors to the upper airways. Menthol applied topically to the tracheal mucosa prior to and during citric acid application or administered continuously as vapors or as an aerosol to the lower airways was without effect on cough. These actions of upper airway menthol treatment were mimicked by cold air delivered to the upper airways but not by (+)-menthol, the inactive isomer of menthol, or by the TRPM8/TRPA1 agonist icilin administered directly to the trachea. Subsequent molecular analyses confirmed the expression of TRPM8 in a subset of nasal trigeminal afferent neurons that do not coincidently express TRPA1 or TRPV1. We conclude that menthol suppresses cough evoked in the lower airways primarily through a reflex initiated from the nose.

Protocadherin α (PCDHA) as a novel susceptibility gene for autism

BACKGROUND

Synaptic dysfunction has been shown to be involved in the pathogenesis of autism. We hypothesized that the protocadherin α gene cluster (PCDHA), which is involved in synaptic specificity and in serotonergic innervation of the brain, could be a suitable candidate gene for autism.

METHODS

We examined 14 PCDHA single nucleotide polymorphisms (SNPs) for genetic association with autism in DNA samples of 3211 individuals (841 families, including 574 multiplex families) obtained from the Autism Genetic Resource Exchange.

RESULTS

Five SNPs (rs251379, rs1119032, rs17119271, rs155806 and rs17119346) showed significant associations with autism. The strongest association (p < 0.001) was observed for rs1119032 (z score of risk allele G = 3.415) in multiplex families; SNP associations withstand multiple testing correction in multiplex families (p = 0.041). Haplotypes involving rs1119032 showed very strong associations with autism, withstanding multiple testing corrections. In quantitative transmission disequilibrium testing of multiplex fam - ilies, the G allele of rs1119032 showed a significant association (p = 0.033) with scores on the Autism Diagnostic Interview-Revised (ADI-R)_D (early developmental abnormalities). We also found a significant difference in the distribution of ADI-R_A (social interaction) scores between the A/A, A/G and G/G genotypes of rs17119346 (p = 0.002).

LIMITATIONS

Our results should be replicated in an independent population and/or in samples of different racial backgrounds.

CONCLUSION

Our study provides strong genetic evidence of PCDHA as a potential candidate gene for autism.