Comprehensive analysis of a novel mouse model of the 22q11.2 deletion syndrome: a model with the most common 3.0-Mb deletion at the human 22q11.2 locus

The 22q11.2 deletion syndrome (22q11.2DS) is associated with an increased risk for psychiatric disorders. Although most of the 22q11.2DS patients have a 3.0-Mb deletion, existing mouse models only mimic a minor mutation of 22q11.2DS, a 1.5-Mb deletion. The role of the genes existing outside the 1.5-Mb deletion in psychiatric symptoms of 22q11.2DS is unclear. In this study, we generated a mouse model that reproduced the 3.0-Mb deletion of the 22q11.2DS (Del(3.0 Mb)/ +) using the CRISPR/Cas9 system. Ethological and physiological phenotypes of adult male mutants were comprehensively evaluated by visual-evoked potentials, circadian behavioral rhythm, and a series of behavioral tests, such as measurement of locomotor activity, prepulse inhibition, fear-conditioning memory, and visual discrimination learning. As a result, Del(3.0 Mb)/ + mice showed reduction of auditory prepulse inhibition and attenuated cue-dependent fear memory, which is consistent with the phenotypes of existing 22q11.2DS models. In addition, Del(3.0 Mb)/ + mice displayed an impaired early visual processing that is commonly seen in patients with schizophrenia. Meanwhile, unlike the existing models, Del(3.0 Mb)/ + mice exhibited hypoactivity over several behavioral tests, possibly reflecting the fatigability of 22q11.2DS patients. Lastly, Del(3.0 Mb)/ + mice displayed a faster adaptation to experimental jet lag as compared with wild-type mice. Our results support the validity of Del(3.0 Mb)/ + mice as a schizophrenia animal model and suggest that our mouse model is a useful resource to understand pathogenic mechanisms of schizophrenia and other psychiatric disorders associated with 22q11.2DS.

Metal Artifact Reduction in Head CT Performed for Patients with Deep Brain Stimulation Devices: Effectiveness of a Single-Energy Metal Artifact Reduction Algorithm

BACKGROUND AND PURPOSE

Deep brain stimulation electrodes induce massive artifacts on CT images, deteriorating the diagnostic value of examinations. We aimed to investigate the usefulness and potential limitations of a single-energy metal artifact reduction algorithm in head CT performed in patients with implanted deep brain stimulation devices.

MATERIALS AND METHODS

Thirty-four patients with deep brain stimulation (bilateral, n = 28) who underwent head CT on a 320-detector row scanner and whose images were reconstructed with and without single-energy metal artifact reduction at the examinations were retrospectively included. The severity of artifacts around electrodes was assessed objectively using SDs and an artifact index. Two radiologists subjectively evaluated the severity of artifacts from electrodes, the visibility of electrode localization and surrounding structures, and overall diagnostic confidence on 4-point scales. Background image quality (GM-WM contrast and image noise) was subjectively and objectively assessed. The presence and location of artifacts newly produced by single-energy metal artifact reduction were analyzed.

RESULTS

Single-energy metal artifact reduction provided lower objective and subjective metal artifacts and improved visualization of electrode localization and surrounding structures and diagnostic confidence compared with non-single-energy metal artifact reduction images, with statistical significance (all, P < .01). No significant differences were observed in GM-WM contrast and image noise (all, P ≥ .11). The new artifacts from single-energy metal artifact reduction were prominently observed in patients with bilateral deep brain stimulation at high convexity, possibly induced by deep brain stimulation leads placed under the parietal scalp.

CONCLUSIONS

Single-energy metal artifact reduction substantially reduces the metal artifacts from deep brain stimulation electrodes and improves the visibility of intracranial structures without affecting background image quality. However, non-single-energy metal artifact reduction images should be simultaneously reviewed to accurately assess the entire intracranial area, particularly in patients with bilateral deep brain stimulation.

Low-charge-state ion production by a laser ion source for the TIARA ion implanter

Ion implanters require various kinds of heavy-ion beams in low-charge states for material science experiments. For this purpose, a laser ion source has been developed for the ion implanter at Takasaki Ion Accelerators for Advanced Radiation Application. In this study, we investigated the particle number of ions per laser pulse for each charge state in the laser-produced carbon plasma. In the experiment, the carbon plasma was generated from a graphite target using a Nd:YAG laser (1064 nm wavelength, 5 ns pulse width) at a laser energy of 37.5 mJ, 28.3 mJ, or 15.6 mJ. The particle number of ions in the plasma was evaluated from the time-integrated value of each ion-charge-state's current signal by placing the focusing lens at various positions. We found that the particle number of carbon ions was the highest for singly charged ions at all laser energies, with particle number in the order of 10¹⁰ ions obtained at a 1-m distance from the target surface.

Comparison of angioscopy and histopathology for the evaluation of carotid plaque characteristics: an ex vivo validation study

Intravascular angioscopy is widely used for evaluating plaque characteristics through the plaque color in the coronary artery. This study evaluated whether angioscopy is capable of identifying various plaque morphologies, including necrotic core and intraplaque hemorrhage (IPH) in the carotid artery. Nine patients underwent carotid endarterectomy for carotid artery stenosis, and these specimens were imaged ex vivo by angioscopy within 6 h. An angioscopic examination of carotid plaque evaluated its color intensity as follows: white, yellow, or red. The IPH area, necrotic core area, and fibrous cap thickness was measured on histological sections at each site. A total of 7 plaques were graded as white plaques, 10 as yellow, and 8 as red by angioscopy. The IPH area and the percent area occupied by IPH were larger in red and yellow plaques than in white plaques (10.7 ± 9.3 mm², 9.4 ± 7.8 mm², and 2.2 ± 1.7 mm², respectively, P = 0.074; and 25 ± 10%, 19 ± 13%, and 7 ± 5%, respectively, P = 0.008). Furthermore, the thickness of the fibrous cap was significantly thinner in red plaques than in yellow and white plaques (128 ± 34 µm, 328 ± 136 µm, and 285 ± 102 µm, respectively, P = 0.002). The ROC analysis for predicting a presence of red plaques identified that the optimal cutoff value of fibrous cap thickness was 181 µm (area under the curve = 0.987, 100% sensitivity, 90% specificity). The prevalence of red plaques on intravascular angioscopy may represent the existence of plaques containing relatively larger necrotic core and IPH with a thin fibrous cap.

Usefulness of a New Electronic Conductivity Device with a Pedicle Probe and a Multi-axis Angiography Unit for Inserting a C1 Lateral Mass Screw Safely and Tightly: A Technical Note

The C1 lateral mass screw (LMS) is widely used as one of the screws for atlantoaxial fixation. Tight bicortical screwing from the posterior to anterior cortical margin of the atlas is recommended. However, important structures, such as the internal carotid artery, are located around this area so precision is required to avoid injuring them. We describe the usefulness of a new electronic conductivity device (ECD) with a pedicle probe and a multi-axis angiography unit for inserting the C1 LMS. Four consecutive patients who were treated with C1 and C2 posterior fixation using an ECD and a multi-axis angiography unit in the hybrid operating room were included. All patients were treated successfully. Seven of eight bicortical screws could be inserted into the perfectly ideal location. The median (interquartile range) distance from the anterior margin of the atlas to the tip of the screw was 0.81 mm (0.43, 1.21 mm). This study suggested that the ECD and multi-axis angiography unit are useful for inserting the C1 LMS safely and tightly.

Functional roles of the glial glutamate transporter (GLAST) in emotional and cognitive abnormalities of mice after repeated phencyclidine administration

Alterations of the glutamatergic system components, including N-methyl-d-aspartate (NMDA) receptors are relevant to the pathophysiology of schizophrenia. Repeated phencyclidine (PCP) administration induces several schizophrenia-like psychobehavioral abnormalities and decreases extracellular glutamate levels, which are associated with increased levels of glial glutamate and aspartate transporter (GLAST) in the prefrontal cortex (PFC) of mice. In the present study, we investigated the functional roles of GLAST in the emotional and cognitive abnormalities in mice following repeated PCP administration by using GLAST heterozygous (+/-) mice, since GLAST mutant mice are a useful tool for elucidating the contribution of glutamate dysfunction to the pathophysiology of schizophrenia. PCP-administered GLAST wild-type (+/+) mice showed enhancement of immobility in a forced swimming test, impairments of visual recognition memory in a novel object recognition test, decrease in high potassium (K⁺)-induced extracellular glutamate release, and overexpression of GLAST and S100 proteins in the PFC, compared to saline-administered GLAST^+/+ mice. Such behavioral and neurochemical abnormalities were not observed in PCP-administered GLAST^+/- mice. In conclusion, these results clearly suggest that genetic GLAST dysfunction and glial activation play important roles in the development of emotional and cognitive abnormalities in PCP-administered GLAST^+/+ mice.

Basic evaluation of a novel 4D target and human body phantom

Stereotactic body radiation therapy (SBRT) is usually verified with a dynamic phantom or solid phantom, but there is a demand for phantoms that can accurately simulate tumor dynamics within an individual that would allow customized validation in every patient. We developed a new 4D dynamic target phantom (multi-cell 4D phantom) that allows simulation of tumor movement in patients. The basic quality and dynamic reproducibility of this new phantom was verified in this investigation. The newly developed multi-cell 4D phantom comprises four main components: soft tissue, bones, lungs, and tumor (target). The phantom structure was based on computed tomography (CT) data of a male. In this study, we investigated the basic performance of a multi-cell 4D phantom. All the CT numbers of the phantom were very close to those of human data. The geometric maximum amplitudes were 4.57 mm in the lateral direction, 4.59 mm in the ventrodorsal direction, and 3.68 mm in the cranio-caudal direction. Geometric errors were 0.84, 0.58, and 0.40 mm, respectively. Movements of the abdominal surface were stable for 60 s. Repeated measurements show no actual differences in target movements between multiple measurements and indicated high reproducibility (r  >  0.97). End-to-end tests using Gafchromic film revealed a gamma pass rate of 98% or above (2 mm/3%). Although our phantom performed limited reproducibility in the movement of the patient tumor at present, a satisfactory level of precision was confirmed in general. This is a very promising device for use in the verification of radiation therapy for moving targets.

A Polymorphism rs6726395 in Nrf2 Contributes to the Development of Emphysema-Associated Age in Smokers Without COPD

INTRODUCTION

Several studies have reported that single nucleotide polymorphisms (SNPs) in the gene encoding NF-E2-related factor 2 (Nrf2) contribute to airflow limitations in smokers without COPD. Although small airway lesions and emphysema contribute cooperatively to airflow limitation, the relationship between Nrf2 SNPs and the development of emphysema in smokers without COPD is not well understood.

METHODS

Healthy subjects who underwent an annual health checkup with computed tomography (CT) of the chest at Osaka City University Hospital were prospectively recruited. The percentage of low-attenuation area (%LAA) on chest CT was quantified, and correlations between %LAA, Nrf2 SNP [rs6726395 (G/A)] genotypes, and clinical characteristics were examined.

RESULTS

A total of 245 subjects without COPD [non-/light-smoker: 153 (62.4%) and smoker: 92 (37.6%)] were enrolled. The %LAA in the upper lung field was higher than that in the lower lung field (p < 0.001). The %LAA in smokers was significantly higher than that in non-/light-smokers (p = 0.021). The %LAA showed significant but weak correlation with age in all subjects (r = 0.141, p = 0.028). Divided by genotype, the %LAA of the upper lung field was significantly correlated with age in smokers with genotype GG (wild type) (r = 0.333, p = 0.022), but was not significantly correlated with age in smokers with genotype AG/AA. These correlations were not observed in non-/light smokers.

CONCLUSION

A polymorphism rs6726395 in Nrf2 can contribute to the development of emphysema-associated aging in smokers. The Nrf2 SNP may be a predictive factor for smoking-induced emphysema, and genotyping of Nrf2 SNP may serve as biomarker for emphysema prevention.

Methylation analysis for postpartum depression: a case control study

BACKGROUND

Postpartum depression (PPD) is a major depressive disorder that occurs after childbirth. Objective diagnostic and predictive methods for PPD are important for early detection and appropriate intervention. DNA methylation has been recognized as a potential biomarker for major depressive disorder. In this study, we used methylation analysis and peripheral blood to search for biomarkers that could to lead to the development a predictive method for PPD.

METHODS

Study participants included 36 pregnant women (18 cases and 18 controls determined after childbirth). Genome-wide DNA methylation profiles were obtained by analysis with an Infinium Human Methylation 450BeadChip. The association of DNA methylation status at each DNA methylation site with PPD was assessed using linear regression analysis. We also conducted functional enrichment analysis of PPD using The Database for Annotation, Visualization and Integrated Discovery 6.8 to explore enriched functional-related gene groups for PPD.

RESULTS

In the analysis with postpartum depressed state as an independent variable, the difference in methylation frequency between the postpartum non-depressed group and the postpartum depressed group was small, and sites with genome-wide significant differences were not confirmed. After analysis by The Database for Annotation, Visualization and Integrated Discovery 6.8, we revealed four gene ontology terms, including axon guidance, related to postpartum depression.

CONCLUSIONS

These findings may help with the development of an objective predictive method for PPD.

[Exploring Molecular Targets for Epilepsy Treatment from the Perspective of Neuronal Homeostasis]

Brain function is controlled by the balance between the excitatory and inhibitory systems. If this balance is disrupted and the excitatory system dominates, convulsions or epileptic seizures are induced. Neuronal hyperexcitability in the brain leads to marked changes in the function of the neurons, which adversely affect the stability of the neural network. Many of the currently used antiepileptic drugs are symptomatic treatments that suppress the electrical hyperexcitability of the cerebrum. Although patients with epilepsy should continuously take antiepileptic drugs to control their seizures, approximately 20% of patients are drug resistant. The brain has the ability to control neuronal functions within acceptable limits while it maintains the amount of synaptic inputs that form the basis of information accumulation. Neuronal self-regulation is known as homeostatic scaling by which the intensity of all excitatory synapses is suppressed when neuronal excitability is increased. However, the molecular mechanisms of homeostatic scaling and their pathophysiological significance in vivo remain unclear. Repeated treatment with a subconvulsive dosage of pentylenetetrazol (PTZ), a γ-aminobutyric acid (GABA)_A receptor antagonist, is known to induce kindling in mice, which is a common animal model used to study epilepsy. We found that PTZ-induced kindling was potentiated in mice deficient in the transcription factor neuronal PAS domain protein 4 (Npas4), the expression of which is immediately induced in response to neuronal activity. At this symposium, we will discuss the possibility of Npas4 as a novel target molecule for epilepsy treatment.

[Physiological centers of decision-making: manipulation of neural activity in insular cortex by AAV]

Decision-making is a key activity process that influences many aspects of daily living and both mental and physical health. In general, healthy participants reveal rational choice, but patients with neuropsychiatric disorders reveal irrational and risky choice in decision-making. Addiction is one of typical diseases revealed risky decision-making, addicts select risky action and options that confer short-term rewards at the cost of long-term disadvantages. Thus, irrational and risky decision-making is recognized as a core problem in patients with neuropsychiatric disorders, and a better understanding of the mechanisms underlying altered decision-making would provide insights into potential therapeutic approaches for these diseases. However, the neural pathway and substrates underlying these deficits are particularly unknown. Recently, we found that insular cortex is one of key regions for risky decision-making in an animal model of methamphetamine addiction, by using the designer receptor exclusively activated by designer drug (DREADD) technology, and that GABAergic dysfunction in insular cortex is involved in evaluating the subjective value of reward and reward prediction error. These brain dysfunctions would be related to risk taking behavior in addiction. In this review, we introduced the possible neural pathway related to risky decision-making and behavioral changes in choice strategy using adeno associated virus (AAV).

Author Correction: Proteomic analysis of lymphoblastoid cell lines from schizophrenic patients

The original Article required a few updates; one co-author name, which was given as Hiroki Kiumura, has been updated to Hiroki Kimura. Furthermore, supplementary information has been updated, and grant numbers have been added. These updates have been made to both the PDF and HTML versions of this Article.

Proteomic analysis of lymphoblastoid cell lines from schizophrenic patients

Although a number of studies have identified several convincing candidate genes or molecules, the pathophysiology of schizophrenia (SCZ) has not been completely elucidated. Therapeutic optimization based on pathophysiology should be performed as early as possible to improve functional outcomes and prognosis; to detect useful biomarkers for SCZ, which reflect pathophysiology and can be utilized for timely diagnosis and effective therapy. To explore biomarkers for SCZ, we employed fluorescence two-dimensional differential gel electrophoresis (2D-DIGE) of lymphoblastoid cell lines (LCLs) (1st sample set: 30 SCZ and 30 CON). Differentially expressed proteins were sequenced by liquid chromatography tandem-mass spectrometry (LC-MS/MS) and identified proteins were confirmed by western blotting (WB) (1st and 2nd sample set: 60 SCZ and 60 CON). Multivariate logistic regression analysis was performed to identify an optimal combination of biomarkers to create a prediction model for SCZ. Twenty protein spots were differentially expressed between SCZ and CON in 2D-DIGE analysis and 22 unique proteins were identified by LC-MS/MS. Differential expression of eight of 22 proteins was confirmed by WB. Among the eight candidate proteins (HSPA4L, MX1, GLRX3, UROD, MAPRE1, TBCB, IGHM, and GART), we successfully constructed logistic regression models comprised of 4- and 6-markers with good discriminative ability between SCZ and CON. In both WB and gene expression analysis of LCL, MX1 showed reproducibly significant associations. Moreover, Mx1 and its related proinflamatory genes (Mx2, Il1b, and Tnf) were also up-regulated in poly I:C-treated mice. Differentially expressed proteins might be associated with molecular pathophysiology of SCZ, including dysregulation of immunological reactions and potentially provide diagnostic and prognostic biomarkers.