A CTNNA3 compound heterozygous deletion implicates a role for αT-catenin in susceptibility to autism spectrum disorder

Background

Autism spectrum disorder (ASD) is a highly heritable, neurodevelopmental condition showing extreme genetic heterogeneity. While it is well established that rare genetic variation, both de novo and inherited, plays an important role in ASD risk, recent studies also support a rare recessive contribution.

Methods

We identified a compound heterozygous deletion intersecting the CTNNA3 gene, encoding αT-catenin, in a proband with ASD and moderate intellectual disability. The deletion breakpoints were mapped at base-pair resolution, and segregation analysis was performed. We compared the frequency of CTNNA3 exonic deletions in 2,147 ASD cases from the Autism Genome Project (AGP) study versus the frequency in 6,639 controls. Western blot analysis was performed to get a quantitative characterisation of Ctnna3 expression during early brain development in mouse.

Results

The CTNNA3 compound heterozygous deletion includes a coding exon, leading to a putative frameshift and premature stop codon. Segregation analysis in the family showed that the unaffected sister is heterozygote for the deletion, having only inherited the paternal deletion. While the frequency of CTNNA3 exonic deletions is not significantly different between ASD cases and controls, no homozygous or compound heterozygous exonic deletions were found in a sample of over 6,000 controls. Expression analysis of Ctnna3 in the mouse cortex and hippocampus (P0-P90) provided support for its role in the early stage of brain development.

Conclusion

The finding of a rare compound heterozygous CTNNA3 exonic deletion segregating with ASD, the absence of CTNNA3 homozygous exonic deletions in controls and the high expression of Ctnna3 in both brain areas analysed implicate CTNNA3 in ASD susceptibility.     

Functional identification and monitoring of individual α and β cells in cultured mouse islets of Langerhans

Abstract The aim of the present study was to evaluate, by use of fluorescence microscopy and immunofluorescence stainings, the use of a fluorescent membrane potential sensitive probe as a means to identify and monitor changes in membrane potential of individual cell types in whole islets of Langerhans over time. Our work supports the use of the fluorescent probe bis-(1,3 dibutylbarbituric acid) trimethine oxonol (diBAC₄(3)), in identification of single and cells in the periphery of mouse pancreatic islets cultured on extracellular matrix. At a low extracellular glucose concentration (3 mM), heterogeneous staining of the islets was observed. Approximately 97% of the peripheral cells that stained brightly with diBAC₄(3) were glucagon positive. Additional diBAC₄(3) studies, demonstrated that an increase in glucose concentration from 3 to 10 mM is paralleled by repolarization of cells and depolarization of cells. This suggests that reciprocity of glucagon and insulin release upon glucose stimulation is coupled to divergent changes in membrane potential of these cell types and supports the use of diBAC₄(3) as a means to detect changes in secretion in both cell types.     

The Effect of Prestimulus Alpha Activity on the P300

Trials on which highly discrepant, auditory ‘oddball’ stimuli were presented were sorted into two bins on the basis of prestimulus alpha band RMS magnitude. The trial bins were then separately averaged to produce a ‘high alpha’ auditory ERP (event-related potential) and a ‘low alpha’ ERP for each subject. Study 1 found that larger amplitude P300s were obtained in the ‘high alpha’ ERP. No effect of alpha was found on the N100. Study 2 employed extra factors of stimulus intensity change (increases and decreases) and alpha measurement period (before and after the ‘oddball’ stimulus). It was found that P300 amplitude enhancement was independent of both stimulus intensity and the amount of alpha poststimulus. The data are discussed in terms of cascaded inhibition from the mesencephalic reticular formation to nucleus reticularis of the thalamus to a thalamo-cortical system responsible for the generation of both alpha and the P300.     

甲胎蛋白、游离雌三醇及绒毛膜促性腺激素测定在产前诊断唐氏综合征中的应用

目的：探讨胎儿胎盘产物甲胎蛋白（ＡＦＰ）、游离雌三醇（ｕＥ３）和β绒毛膜促性腺激素（β－ｈＣＧ）水平与胎儿唐氏综合征发病的关系。方法：用放射免疫法测定１７例妊娠唐氏综合征胎儿的孕妇（病例组）和１３１例妊娠正常胎儿孕妇（对照组）的外周血、羊水及脐血中ＡＦＰ、ｕＥ３和β－ｈＣＧ水平。结果：病例组孕妇外周血、羊水和脐血中ＡＦＰ水平均低于对照组（Ｐ＜０．０５）；ｕＥ３水平也均低于对照组（Ｐ＜０．０５）；β－ｈＣＧ水平均高于对照组（Ｐ＜０．０５）。结论：检测孕妇外周血中ＡＦＰ、ｕＥ３、β－ｈＣＧ可用于胎儿唐氏综合征的产前诊断     

Reduced alpha and exaggerated theta power during the resting-state EEG in fragile X syndrome

This study characterizes the resting-state EEG in males with fragile X syndrome to reveal abnormalities in oscillatory brain dynamics. Analyses of the eyes-closed EEG epochs showed that the resting-state EEG in FXS can be characterized by elevated relative theta power (4–8 Hz) and reduced relative upper-alpha power (10–12 Hz). Although preliminary, these findings suggest that the well-documented imbalance in excitatory/inhibitory cortical circuit activity in FXS can be revealed the level of oscillatory behavior at the scalp. A next step for future studies is linking the EEG resting-state indices to cognitive and behavioral measures.     

Adrenergic influences on the control of blood-brain barrier permeabilit

Summary The central adrenergic innervation of the cerebral microvessels may play a role in the control of blood-brain barrier permeability. To pursue the study of this hypothesis we investigated the effect of noradrenaline on both the permeability of the blood-brain barrier to sodium fluorescein and on the pinocytotic activity of cerebral endothelial cells in the rat. Noradrenaline, stereotactically injected in the right lateral cerebral ventricle, significantly increased the cerebral extraction ratio of sodium fluorescein in a dose-dependent way. The same effect was induced by phenylephrine. Prostaglandin F₂ had no significant effect on the passage of sodium fluorescein through the blood-brain barrier.The effect of noradrenaline (150 µg) on the cerebral extraction ratio of sodium fluorescein was totally blocked by phenoxybenzamine (25 mg/kg i.p., 24 h before noradrenaline). Noradrenaline (150 µg) significantly increased the pinocytotic activity of cerebral endothelial cells. Phenoxybenzamine (as above) reduced the effect of noradrenaline on pinocytosis.It is concluded that noradrenaline increases the blood-brain barrier's permeability to sodium fluorescein, most probably through an effect on alpha adrenoceptors. The increase induced in the blood-brain barrier's permeability by noradrenaline seems to be due, at least in part, to an increase in the pinocytotic activity of endothelial cells. Send offprint requests to A. Sarmento at the above address     

F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer

Background and purpose

We evaluate the contribution of ¹⁸F-choline PET/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques.

Materials and methods

Seventeen patients with local-only recurrent prostate cancer (median = 5.7 years) after initial irradiation were included in the study. Rebiopsies were performed in 10 patients that confirmed the local recurrence. Following injection of 300 MBq of ¹⁸F-fluorocholine, dynamic PET frames (3 min each) were reconstructed from the list-mode acquisition. Five PET image segmentation techniques were used to delineate the ¹⁸F-choline-based GTVs. These included manual delineation of contours (GTV_man) by two teams consisting of a radiation oncologist and a nuclear medicine physician each, a fixed threshold of 40% and 50% of the maximum signal intensity (GTV_40% and GTV_50%), signal-to-background ratio-based adaptive thresholding (GTV_SBR), and a region growing (GTV_RG) algorithm. Geographic mismatches between the GTVs were also assessed using overlap analysis.

Results

Inter-observer variability for manual delineation of GTVs was high but not statistically significant (p = 0.459). In addition, the volumes and shapes of GTVs delineated using semi-automated techniques were significantly higher than those of GTVs defined manually.

Conclusions

Semi-automated segmentation techniques for ¹⁸F-choline PET-guided GTV delineation resulted in substantially higher GTVs compared to manual delineation and might replace the latter for determination of recurrent prostate cancer for partial prostate re-irradiation. The selection of the most appropriate segmentation algorithm still needs to be determined.     

Protective effect of alpha-lipoic acid in methotrexate-induced ovarian oxidative injury and decreased ovarian reserve in rats

To determine whether the possible oxidative effect of methotrexate (Mtx) on ovary and to evaluate the effectiveness of alpha lipoic acid (ALA), which may be useful in many oxidative stress models.

Thirty-two female Wistar-albino rats were randomly divided into four groups; control group, alpha lipoic acid group (ALA 100?mg/kg, 10?days), multiple dose Mtx group (Mtx 1?mg/kg 1, 3, 5, 7?days) and Mtx and ALA group (Mtx 1?mg/kg 1, 3, 5, 7?days and ALA 100?mg/kg, 10?days). Serum total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI), tumor necrosis factor-alpha (TNF-α), tissue malondialdehyde (MDA) and activities of glutathione peroxidase (GSH-Px) and catalase (CAT) and anti-Mullerian hormone (AMH) and total ovarian follicle count were evaluated.

Mtx administration caused a significant decrease in TAS, a significant increase in TOS and OSI, a significant increase in MDA levels and a decrease in GSH-Px and CAT activity. Moreover the proinflammatory cytokine (TNF-α) was increased in the Mtx group. And AMH values and total follicle count were significantly decreased in Mtx group. However, ALA treatment reversed biochemical results and AMH levels and total follicle count.

Alpha lipoic acid ameliorates methotrexate induced oxidative damage of ovarian in rats.     

Nicotine improves probabilistic reward learning in wildtype but not alpha7 nAChR null mutants,yet alpha7 nAChR agonists do not improve probabilistic learning

Cognitive impairments, e.g., reward learning, are present in various psychiatric disorders and warrant treatment. Improving reward-related learning could synergistically enhance psychosocial treatments and cognition generally. A critical first step is to understand the mechanisms underlying reward learning. The dopamine system has been implicated in such learning, but less known is how indirect activation of this system may affect reward learning. We determined the role of alpha7 nicotinic acetylcholine receptors (nAChR) on a probabilistic reversal learning task (PRLT) in mice that includes reward and punishment. Male alpha7 knockout (KO), heterozygous (HT), and wildtype (WT) littermate mice (n?=?84) were treated with vehicle, 0.03, or 0.3?mg/kg nicotine. Two cohorts of C57BL/6NJ male mice were treated with various alpha7 nAChR ligands, including the full agonists PNU282877 and AR-R-17779, the positive allosteric modulator CCMI, the partial agonist SSR180711, and the antagonist methyllycaconitine. All mice were then tested in the PRLT. Nicotine (0.3?mg/kg) significantly improved initial reward learning in alpha7 WT and HT mice but did not improve learning in KO mice, suggesting an involvement of the alpha7 nAChR in the pro-learning effects of nicotine. Neither alpha7 nAChR treatments (PNU282987, AR-R-17779, CCMI, SSR180711, nor methyllycaconitine) affected mouse PRLT performance however. Nicotine improved reward learning via a mechanism that may include alpha7 nAChRs. This improvement unlikely relied solely on alpha7 nAChRs however, since no alpha7 nAChR ligand improved reward learning in normal mice. Future assessments of the effects of other nAChR subtypes on reward learning are needed.     

Selective ablation of dorsal horn NK1 expressing cells reveals a modulation of spinal alpha2-adrenergic inhibition of dorsal horn neurones

Activity in descending systems from the brainstem modulates nociceptive transmission through the dorsal horn. Intrathecal injection of the neurotoxin saporin conjugated to SP (SP-SAP) into the lumbar spinal cord results in the selective ablation of NK(1) receptor expressing (NK(1)+ve) neurones in the superficial dorsal horn (lamina I/III). Loss of these NK(1)+ve neurones attenuates excitability of deep dorsal horn neurones due to a disruption of both intrinsic spinal circuits and a spino-bulbo-spinal loop, which activates a descending excitatory drive, mediated through spinal 5HT(3) receptors. Descending inhibitory pathways also modulate spinal activity and hence control the level of nociceptive transmission relayed to higher centres. To ascertain the spinal origins of the major descending noradrenergic inhibitory pathway we studied the effects of a selective alpha2-adrenoceptor antagonist, atipamezole, on neuronal activity in animals pre-treated with SP-SAP. Intrathecal application of atipamezole dose dependently facilitated the mechanically evoked neuronal responses of deep dorsal horn neurones to low intensity von Frey hairs (5-15 g) and noxious thermal (45-50 degrees C) evoked responses in SAP control animals indicating a physiological alpha2-adrenoceptor control. This facilitatory effect of atipamezole was lost in the SP-SAP treated group. These data suggest that activity within noradrenergic pathways have a dependence on dorsal horn NK(1)+ve cells. Further, noradrenergic descending inhibition may in part be driven by lamina I/III (NK(1)+ve) cells, and mediated via spinal alpha2-adrenoceptor activation. Since the same neuronal population drives descending facilitation and inhibition, the reduced excitability of lamina V/VI WDR neurones seen after loss of these NK(1)+ve neurones indicates a dominant role of descending facilitation.