Cutaneous ischemia-reperfusion injury is exacerbated by IL-36 receptor antagonist deficiency

BACKGROUND

Loss-of-function homozygous or compound heterozygous mutations in IL36RN, which encodes interleukin-36 receptor antagonist (IL-36Ra), has been implicated in the pathogenesis of skin disorders. However, the pathogenic role of IL-36Ra in cutaneous ischemia-reperfusion (I/R) injury remains unclear.

OBJECTIVES

We investigated the role of IL36Ra in cutaneous I/R injury.

METHODS

We examined I/R injury in Il36rn^-/- mice. The area of wounds, numbers of infiltrated cells, apoptotic cells and neutrophil extracellular trap (NET) formation were assessed. The expression levels of various genes were analysed using real-time RT-PCR. The expression of high mobility group box 1 (HMGB1), an endogenous toll-like receptor (TLR) 4 ligand, was confirmed using immunohistology, and serum HMGB1 levels were measured by ELISA. Cytokine production by stimulated cultured J774A.1 and HaCaT cells was examined.

RESULTS

IL-36Ra deficiency resulted in significantly delayed wound healing and increased neutrophil and macrophage infiltration into the wound tissues. Il36rn^-/- mice had increased mRNA expression levels of CXCL1, CXCL2, CCL4, TNF-α, TGF-β, IL-1β, IL-6 and IL-36γ relative to wild-type mice. Apoptosis was identified in keratinocytes by TUNEL assay. HMGB1 expression in the I/R site was decreased in both keratinocytes and adnexal cells, while serum HMGB1 levels were significantly elevated after reperfusion. The mRNA levels of various cytokines, including IL-1β, were elevated in J774A.1 cells through TLR4 signalling by HMGB1 stimulation. In addition, HaCaT cells stimulated with IL-1β showed significantly increased CXCL1, TNF-α, IL-6, IL-36β and IL-36γ mRNA expression. Furthermore, NET formation was increased by IL-36Ra deficiency. Finally, either the blockade of TLR4 signalling by TAK-242 or inhibition of NET formation by Cl-amidine normalized exacerbated I/R injury in Il36rn^-/- mice.

CONCLUSIONS

This study indicated that IL-36Ra deficiency exacerbates cutaneous I/R injury due to excessive inflammatory cell recruitment, NET formation, and excessive cytokine and chemokine production via the TLR4 pathway by HMGB1 released from epidermal apoptotic cells.

Cardiac amyloidosis in patients undergoing aortic valve replacement for aortic stenosis

Background

Transthyretin cardiac amyloidosis (ATTR) has been increasingly recognized in patients with degenerative aortic stenosis (AS). In some reports, the uptake of Tc-99m labeled bone radiotracers in cardiac amyloidosis has been documented. Tc-99m pyrophosphate (PYP) scintigraphy in the absence of evidence of a monoclonal gammopathy was diagnostic for transthyretin cardiac amyloidosis, providing a cost-effective and non-invasive technique with a specificity and positive predictive value of nearly 100%. We sought to determine the prevalence of ATTR as detected by the bone scan tracer among the patients with severe AS requiring surgical valve replacement.

Methods

We retrospectively analyzed clinical and echocardiographical data for 44 patients with severe AS requiring surgical valve replacement between Jan. 2009 and Dec. 2016. All eligible patients were offered Tc-99m PYP scintigraphy. Retention of Tc-99m PYP in the heart was assessed using both a semiquantitative visual score (range, 0 [no uptake] to 3 [uptake greater than bone]). Positive uptake was defined score 2 and 3.

Results

Myocardial deposition of Tc-99m PYP (Score 2–3) was identified in 4 of 44 patients (9%), all >70 years and 75% male. Patients with myocardial deposition of the tracer were older (78±8 years vs. 70±12 years), and had more mean interventricular septum thickness (18±3 mm vs. 14±5 mm). Both groups had at least ejection fraction and abnormal global longitudinal strain with no significant difference between groups. Pre-operative serum median NT-pro BNP level was similar between two groups, but post-operative improvement of NT-pro BNP was larger in non-deposition of the tracer group. During the post operative follow-up, survival was significantly worse if patients had amyloid deposition compared with no deposition subjects (25% vs. 7.5%).

Conclusion

Incidental transthyretin cardiac amyroidosis had a prevelance of 9% among patients undergoing surgical aortic valve replacement and was associated with a poor outcome.

Funding Acknowledgement

Type of funding source: None

A potential role of fatty acid binding protein 4 in the pathophysiology of autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder characterized by difficulties in social communication and interaction, as well as repetitive and characteristic patterns of behaviour. Although the pathogenesis of autism spectrum disorder is unknown, being overweight or obesity during infancy and low weight at birth are known as risks, suggesting a metabolic aspect. In this study, we investigated adipose tissue development as a pathophysiological factor of autism spectrum disorder by examining the serum levels of adipokines and other metabolic markers in autism spectrum disorder children (n = 123) and typically developing children (n = 92) at 4–12 years of age. Among multiple measures exhibiting age-dependent trajectories, the leptin levels displayed different trajectory patterns between autism spectrum disorder and typically developing children, supporting an adipose tissue-dependent mechanism of autism spectrum disorder. Of particular interest, the levels of fatty acid binding protein 4 (FABP4) were significantly lower in autism spectrum disorder children than in typically developing subjects, at preschool age (4–6 years old: n = 21 for autism spectrum disorder and n = 26 for typically developing). The receiver operating characteristic curve analysis discriminated autism spectrum disorder children from typically developing children with a sensitivity of 94.4% and a specificity of 75.0%. We re-sequenced the exons of the FABP4 gene in a Japanese cohort comprising 659 autism spectrum disorder and 1000 control samples, and identified two rare functional variants in the autism spectrum disorder group. The Trp98Stop, one of the two variants, was transmitted to the proband from his mother with a history of depression. The disruption of the Fabp4 gene in mice evoked autism spectrum disorder-like behavioural phenotypes and increased spine density on apical dendrites of pyramidal neurons, which has been observed in the postmortem brains of autism spectrum disorder subjects. The Fabp4 knockout mice had an altered fatty acid composition in the cortex. Collectively, these results suggest that an ‘adipo-brain axis’ may underlie the pathophysiology of autism spectrum disorder, with FABP4 as a potential molecule for use as a biomarker.

Ion species discrimination method by linear energy transfer measurement in Fujifilm BAS-SR imaging plate

We have developed a novel discrimination methodology to identify ions in multispecies beams with similar charge-to-mass ratios, but different atomic numbers. After an initial separation by charge-to-mass ratios using co-linear electric and magnetic fields, individual ions can be discriminated by considering the linear energy transfer of ions irradiating a stimulable phosphor plate (Fujifilm imaging plate) by comparison with the Monte Carlo calculation. We apply the method to energetic multispecies laser-driven ion beams and use it to identify silver ions produced by the interaction between a high contrast, high intensity laser pulse; and a sub-micrometer silver foil target. We also show that this method can be used to calibrate the imaging plate for arbitrary ion species in the range of Z ≥ 6 with dE/dx > 0.1 MeV/μm without requiring individual calibration.

VLDL-specific increases of fatty acids in autism spectrum disorder correlate with social interaction

BACKGROUND

Abnormalities of lipid metabolism contributing to the autism spectrum disorder (ASD) pathogenesis have been suggested, but the mechanisms are not fully understood. We aimed to characterize the lipid metabolism in ASD and to explore a biomarker for clinical evaluation.

METHODS

An age-matched case-control study was designed. Lipidomics was conducted using the plasma samples from 30 children with ASD compared to 30 typical developmental control (TD) children. Large-scale lipoprotein analyses were also conducted using the serum samples from 152 children with ASD compared to 122 TD children. Data comparing ASD to TD subjects were evaluated using univariate (Mann-Whitney test) and multivariate analyses (conditional logistic regression analysis) for main analyses using cofounders (diagnosis, sex, age, height, weight, and BMI), Spearman rank correlation coefficient, and discriminant analyses.

FINDINGS

Forty-eight significant metabolites involved in lipid biosynthesis and metabolism, oxidative stress, and synaptic function were identified in the plasma of ASD children by lipidomics. Among these, increased fatty acids (FAs), such as omega-3 (n-3) and omega-6 (n-6), showed correlations with clinical social interaction score and ASD diagnosis. Specific reductions of very-low-density lipoprotein (VLDL) and apoprotein B (APOB) in serum of ASD children also were found by large-scale lipoprotein analysis. VLDL-specific reduction in ASD was correlated with APOB, indicating VLDL-specific dyslipidaemia associated with APOB in ASD children.

INTERPRETATION

Our results demonstrated that the increases in FAs correlated positively with social interaction are due to VLDL-specific degradation, providing novel insights into the lipid metabolism underlying ASD pathophysiology.

FUNDING

This study was supported mainly by MEXT, Japan.

Experimental study on monitoring system of clinical beam purity in multiple-ion beam operation for heavy-ion radiotherapy

The National Institute of Radiological Sciences has investigated multiple-ion therapy using energetic beams of helium, carbon, oxygen, and neon ions, to improve treatment outcomes of refractory cancer. For this therapy, it is necessary to ensure the helium-ion beam purity to avoid irradiation by unwanted ions. Here, we develop a measurement method for monitoring beam purity. This method can measure the charge number of the ions in a high-purity beam using an ionization chamber and Faraday cup. In addition, it can be used to detect the contamination of the clinical helium-ion beam. We perform beam experiments to evaluate our beam-purity monitoring method and predict that our method is capable of detecting contamination below 1%.

P2725Transthyretin cardiac amyloidosis in heart failure with preserved ejection fraction: Imaging by Tc-99m bone scan

Background

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous clinical syndrome with multiple underlying causes. Transthyretin amyloidosis (ATTR) is an underdiagnosed cause of HFpEF. Extraosseous uptake, in particular, myocardial uptake, was observed in a number of ATTR patients examined with the bone scan tracers.

Objectives

We sought to determine the prevalence of ATTR as detected by the bone scan among the patients admitted due to HFpEF.

Methods

We screened all consecutive patients ≥60 years old admitted due to HFpEF (left ventricular ejection fraction ≥50%). All eligible patients were offered an echocardiogram and a bone scan (a 99mTc-DPD/MDP/HMDP scintigraphy). Echocardiographic and clinical variables were gathered in all the subjects. The intensity of the myocardial uptake was graded according to a visual scale ranging from 0 to 3 points, in which the absence of uptake was assigned a score of 0 points; uptake less than that of bone (referred to as the adjacent rib), 1 point; uptake similar to that of bone, 2 points; and uptake greater than that of bone, 3 points. The distribution of the uptake in myocardium was defined as focal uptake, diffuse uptake, uptake in a ventricular wall segment, diffuse ventricular uptake, or diffuse biventricular uptake.

Results

The study included 62 HFpEF patients (52% women, 73±9 years). The bone scintigraphic analysis revealed relatively intense myocardial uptake in 7 of 62 patients (11.2%). 7 patients had intense Tc-99m uptake (score of 2–3) in the cardiac region, showing deposition in both right and left ventricles in every case. Patients with amyloid deposition were older (78±6 vs. 70±12 years, p<0.05), had a lower systolic blood pressure (118±23 vs. 148±28 mmHg, p<0.05), and left ventricular ejection fraction (52±11 vs. 58±6%, p<0.05). Both groups had at least moderate left ventricular hypertrophy and abnormal global longitudinal strain with no significant difference between groups. In 6 all the cases, the final diagnosis of amyloidosis was based on the results of abdominal fat aspiration biopsy.

Conclusion

ATTR is an underdiagnosed disease that accounts for a significant number (11.2%) of HFpEF cases. These findings create an opportunity for further investigation in the targeted therapy of patients with HFpEF.

A strategy for generating aryl radicals from arylborates through organic photoredox catalysis: photo-Meerwein type arylation of electron-deficient alkenes

Generation of a variety of aryl radicals from arylboronic acids through metal-free photoredox catalysis under mild conditions.

Genetic and molecular risk factors within the newly identified primate-specific exon of the SAP97/DLG1 gene in the 3q29 schizophrenia-associated locus

The synapse-associated protein 97/discs, large homolog 1 of Drosophila (DLG1) gene encodes synaptic scaffold PDZ proteins interacting with ionotropic glutamate receptors including the N-methyl-D-aspartate type glutamate receptor (NMDAR) that is presumed to be hypoactive in brains of patients with schizophrenia. The DLG1 gene resides in the chromosomal position 3q29, the microdeletion of which confers a 40-fold increase in the risk for schizophrenia. In the present study, we performed genetic association analyses for DLG1 gene using a Japanese cohort with 1808 schizophrenia patients and 2170 controls. We detected an association which remained significant after multiple comparison testing between schizophrenia and the single nucleotide polymorphism (SNP) rs3915512 that is located within the newly identified primate-specific exon (exon 3b) of the DLG1 gene and constitutes the exonic splicing enhancer sequence. When stratified by onset age, although it did not survive multiple comparisons, the association was observed in non-early onset schizophrenia, whose onset-age selectivity is consistent with our recent postmortem study demonstrating a decrease in the expression of the DLG1 variant in early-onset schizophrenia. Although the present study did not demonstrate the previously reported association of the SNP rs9843659 by itself, a meta-analysis revealed a significant association between DLG1 gene and schizophrenia. These findings provide a valuable clue for molecular mechanisms on how genetic variations in the primate-specific exon of the gene in the schizophrenia-associated 3q29 locus affect its regulation in the glutamate system and lead to the disease onset around a specific stage of brain development.

Enrichment of deleterious variants of mitochondrial DNA polymerase gene (POLG1) in bipolar disorder

AIM

Rare missense variants, which likely account for a substantial portion of the genetic 'dark matter' for a common complex disease, are challenging because the impacts of variants on disease development are difficult to substantiate. This study aimed to examine the impacts of amino acid substitution variants in the POLG1 found in bipolar disorder, as an example and proof of concept, in three different modalities of assessment: in silico predictions, in vitro biochemical assays, and clinical evaluation. We then tested whether deleterious variants in POLG1 contributed to the genetics of bipolar disorder.

METHODS

We searched for variants in the POLG1 gene in 796 Japanese patients with bipolar disorder and 767 controls and comprehensively investigated all 23 identified variants in the three modalities of assessment. POLG1 encodes mitochondrial DNA polymerase and is one of the causative genes for a Mendelian-inheritance mitochondrial disease, which is occasionally accompanied by mood disorders. The healthy control data from the Tohoku Medical Megabank Organization were also employed.

RESULTS

Although the frequency of carriers of deleterious variants varied from one method to another, every assessment achieved the same conclusion that deleterious POLG1 variants were significantly enriched in the variants identified in patients with bipolar disorder compared to those in controls.

CONCLUSION

Together with mitochondrial dysfunction in bipolar disorder, the present results suggested deleterious POLG1 variants as a credible risk for the multifactorial disease.

Depiction of microglial activation in aging and dementia: Positron emission tomography with [11C]DPA713 versus [11C]( R)PK11195

The presence of activated microglia in the brains of healthy elderly people is a matter of debate. We aimed to clarify the degree of microglial activation in aging and dementia as revealed by different tracers by comparing the binding potential (BP_ND) in various brain regions using a first-generation translocator protein (TSPO) tracer [¹¹C]( R)PK11195 and a second-generation tracer [¹¹C]DPA713. The BP_ND levels, estimated using simplified reference tissue models, were compared among healthy young and elderly individuals and patients with Alzheimer's disease (AD) and were correlated with clinical scores. An analysis of variance showed category-dependent elevation in levels of [¹¹C]DPA713 BP_ND in all brain regions and showed a significant increase in the AD group, whereas no significant changes among groups were found when [¹¹C]( R)PK11195 BP_ND was used. Cognito-mnemonic scores were significantly correlated with [¹¹C]DPA713 BP_ND levels in many brain regions, whereas [¹¹C]( R)PK11195 BP_ND failed to correlate with the scores. As mentioned elsewhere, the present results confirmed that the second-generation TSPO tracer [¹¹C]DPA713 has a greater sensitivity to TSPO in both aging and neuronal degeneration than [¹¹C]( R)PK11195. Positron emission tomography with [¹¹C]DPA713 is suitable for the delineation of in vivo microglial activation occurring globally over the cerebral cortex irrespective of aging and degeneration.

Case report of multiple pustules of the bilateral lower limbs caused by a granulocyte colony-stimulating factor-producing solid pseudopapillary tumour of the pancreas

Here we report a rare case of neutrophilic dermatoses related to a granulocyte colony-stimulating factor (G-CSF)-producing solid pseudopapillary tumour (SPT). The patient was a 39-year-old woman presenting with scattered pustules and crusts of the palms, heels and thighs and plaques of the bilateral lower legs. The skin biopsy revealed dense neutrophil infiltration in the epidermis to the dermis. A pancreatic head tumour was detected using computed tomography. A pathological examination of the resected specimen suggested an SPT. As the skin eruption promptly disappeared after SPT resection, we hypothesized that SPT secretes growth factors including epidermal growth factor (EGF) and G-CSF. The SPT cells stained positive for both EGF and G-CSF tumour cells. The serum levels of interleukin (IL)-6 and IL-10 and tumour necrosis factor-α were within normal limits before and after the SPT resection. In contrast, the serum IL-8, EGF and G-CSF levels decreased after the SPT resection. This is a rare case of neutrophilic dermatoses related to a G-CSF-producing SPT. The present case suggests that physicians should be aware that a G-CSF-producing tumour is a differential diagnosis to consider in patients with unusual aseptic pustulosis.

Serum Wisteria floribunda agglutinin-positive Mac-2-binding protein for patients with chronic hepatitis B and C: a comparative study

We compared Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA⁺ -M2BP) levels between patients with chronic hepatitis B (n=249) and chronic hepatitis C (n=386) based on the degree of liver fibrosis. We examined WFA⁺ -M2BP levels in patients with F4 (cirrhosis), F3 or more (advanced fibrosis) and F2 or more (significant fibrosis) in the two groups. We further examined the relationship between five fibrosis markers and the degree of fibrosis. The WFA⁺ -M2BP values ranged from 0.25 cut-off index (COI) to 12.9 COI in patients with hepatitis B and 0.34-20.0 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F4 in the two groups were 2.83 COI in patients with hepatitis B and 5.03 COI in patients with hepatitis C (P=.0046). The median WFA⁺ -M2BP values in F3 or more in the two groups were 1.79 COI in patients with hepatitis B and 3.79 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F2 or more in the two groups were 1.49 COI in the hepatitis B cohort and 3.19 COI in the hepatitis C group (P<.0001). Among five liver fibrosis markers, WFA⁺ -M2BP had the highest correlation coefficient (r_s =.629) in terms of correlation with the degree of fibrosis in the patients with hepatitis C and had the second highest r_s value (.415) in the hepatitis B group. Although WFA⁺ -M2BP could be a useful indicator of liver fibrosis, WFA⁺ -M2BP levels in the two groups significantly differed even in the same degree of fibrosis. Individual cut-off values in each aetiology for the degree of fibrosis should be determined.

Erratum: Large-Scale Shell-Model Analysis of the Neutrinoless ββ Decay of ^{48}Ca [Phys. Rev. Lett. 116, 112502 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.116.112502.

Bilateral Kienböck’s Disease

We conducted a retrospective review of 11 patients with bilateral Kienböck’s disease from our series of 251 patients with Kienböck’s disease. There were no significant differences in radiographic parameters, including ulnar variance and carpal bone angle, between those with unilateral and those with bilateral Kienböck’s disease. None of the patients with bilateral disease had been treated with corticosteroids or had a systemic disease that predisposed to osteonecrosis. Thus, this study failed to demonstrate any risk factor for bilateral, as opposed to unilateral Kienböck’s disease.

Selective Activity of Various Nucleoside and Nucleotide Analogues against Human Herpesvirus 6 and 7

We have developed a new sensitive enzyme immunoassay (EIA) and MTT (tetrazolium salt) assay for screening compounds against two variants of human herpesvirus 6 (HHV-6A, HHV-6B) and human herpesvirus 7 (HHV-7) and evaluated the anti-HHV-6 and HHV-7 activity of a series of anti-herpesvirus compounds and acyclic nucleoside phosphonate analogues. The results indicate that the pattern of activity of these compounds against these betaherpesviruses is similar to that for human cytomegalovirus (HCMV). The highest potency and selectivity against the two variants of HHV-6 and HHV-7 was demonstrated by S2242 (N7-isomer of 6-deoxy-ganciclovir). Also, ganciclovir (GCV), foscarnet, (phosphonoformic acid; PFA) and the acyclic nucleoside phosphonate analogues such as cidofovir (HPMPC) exhibited selective inhibitory activity against these viruses. Thymidine kinase (TK)-dependent drugs (acyclovir, ACV; brivudin, BVDU; and sorivudine, BVaraU) showed little, if any, activity. These results suggest a structural homology of the DNA polymerase and a lack of TK gene among these three betaherpesviruses (HHV-6, HHV-7 and HCMV). The finding that HHV-7 was highly sensitive to GCV also suggests that HHV-7 may have an HCMV-UL97-homologue gene for the phosphorylation of GCV. The present EIA method is more rapid and sensitive than the previously reported procedures and could be useful for the large-scale screening of compounds against HHV-6 and HHV-7.

Novel stress radiography technique for avulsion fracture of the lateral malleolus in children: a report of three cases

This study reports a novel stress radiography technique to evaluate an avulsion fracture at the lateral malleolus in children. Radiographs in the stress anteroposterior view or the Haraguchi calcaneofibular ligament or anterior tarofibular ligament (ATFL) projection could not detect any fracture; only manual inversion stress radiography in the Haraguchi ATFL projection could identify the avulsion fracture.

Large-Scale Shell-Model Analysis of the Neutrinoless ββ Decay of ^{48}Ca

We present the nuclear matrix element for the neutrinoless double-beta decay of ^{48}Ca based on large-scale shell-model calculations including two harmonic oscillator shells (sd and pf shells). The excitation spectra of ^{48}Ca and ^{48}Ti, and the two-neutrino double-beta decay of ^{48}Ca are reproduced in good agreement to the experimental data. We find that the neutrinoless double-beta decay nuclear matrix element is enhanced by about 30% compared to pf-shell calculations. This reduces the decay lifetime by almost a factor of 2. The matrix-element increase is mostly due to pairing correlations associated with cross-shell sd-pf excitations. We also investigate possible implications for heavier neutrinoless double-beta decay candidates.

Development of a compact ECR ion source for various ion production

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Investigation of the fatty acid transporter-encoding genes SLC27A3 and SLC27A4 in autism

The solute carrier 27A (SLC27A) gene family encodes fatty acid transport proteins (FATPs) and includes 6 members. During fetal and postnatal periods of development, the growing brain requires a reliable supply of fatty acids. Because autism spectrum disorders (ASD) are now recognized as disorders caused by impaired early brain development, it is possible that functional abnormalities of SLC27A genes may contribute to the pathogenesis of ASD. Here, we confirmed the expression of SLC27A3 and SLC27A4 in human neural stem cells derived from human induced pluripotent stem cells, which suggested their involvement in the developmental stage of the central nervous system. Additionally, we resequenced the SLC27A3 and SLC27A4 genes using 267 ASD patient and 1140 control samples and detected 47 (44 novel and 29 nonsynonymous) and 30 (17 novel and 14 nonsynonymous) variants for the SLC27A3 and SLC27A4, respectively, revealing that they are highly polymorphic with multiple rare variants. The SLC27A4 Ser209 allele was more frequently represented in ASD samples. Furthermore, we showed that a SLC27A4 Ser209 mutant resulted in significantly higher fluorescently-labeled fatty acid uptake into bEnd3 cells, a mouse brain capillary-derived endothelial cell line, compared with SLC27A4 Gly209, suggesting that the functional change may contribute to ASD pathophysiology.

Population-dependent contribution of the major histocompatibility complex region to schizophrenia susceptibility

There is consistent data from European cohorts suggesting a genetic contribution from the major histocompatibility complex (MHC) to the pathogenesis of schizophrenia. However, the genomic complexity and ethnicity-specific diversity found in the MHC cause difficulties in identifying causal variants or genes, and there is a need for studies encompassing the entire MHC region in multiple ethnic populations. Here, we report on association signals in the MHC region, with schizophrenia in the Japanese population. We genotyped and imputed a total of 10,131 single nucleotide polymorphisms (SNPs), spanning the entire MHC interval. The analysis included 3302 participants (1518 schizophrenics and 1784 healthy controls) from the Japanese population. In this study, we present evidence for association at rs494620, located in the SLC44A4 gene. The association survived after correction for multiple testing (unadjusted P=7.78×10(-5), empirical P=0.0357). The imputation results detected the highest association at rs707937 in the MSH5-SAPCD1 gene (imputed P=8.40×10(-5)). In expression analysis using postmortem brains from schizophrenia and control samples, MSH5-SAPCD1 showed marginally significant expression differences in Brodmann's area 46 (P=0.044 by unpaired t test with Welch's correction, P=0.099 by Mann-Whitney U test). Our study further strengthens evidence for the involvement of the MHC in schizophrenia across populations, and provides insight into population-specific mechanisms for the MHC region in schizophrenia susceptibility.

Genome-wide Association Study of Autism Spectrum Disorder in the East Asian Populations

Autism spectrum disorder is a heterogeneous neurodevelopmental disorder with strong genetic basis. To identify common genetic variations conferring the risk of ASD, we performed a two-stage genome-wide association study using ASD family and healthy control samples obtained from East Asian populations. A total of 166 ASD families (n = 500) and 642 healthy controls from the Japanese population were used as the discovery cohort. Approximately 900,000 single nucleotide polymorphisms (SNPs) were genotyped using Affymetrix Genome-Wide Human SNP array 6.0 chips. In the replication stage, 205 Japanese ASD cases and 184 healthy controls, as well as 418 Chinese Han trios (n = 1,254), were genotyped by TaqMan platform. Case-control analysis, family based association test, and transmission/disequilibrium test (TDT) were then conducted to test the association. In the discovery stage, significant associations were suggested for 14 loci, including 5 known ASD candidate genes: GPC6, JARID2, YTHDC2, CNTN4, and CSMD1. In addition, significant associations were identified for several novel genes with intriguing functions, such as JPH3, PTPRD, CUX1, and RIT2. After a meta-analysis combining the Japanese replication samples, the strongest signal was found at rs16976358 (P = 6.04 × 10(-7)), which is located near the RIT2 gene. In summary, our results provide independent support to known ASD candidate genes and highlight a number of novel genes warranted to be further investigated in a larger sample set in an effort to improve our understanding of the genetic basis of ASD.

Genetic analysis of the glyoxalase system in schizophrenia

Recent reports suggest that carbonyl stress might affect a subset of schizophrenia patients suffering from severe symptoms. Carbonyl stress protection is achieved by the glyoxalase system consisting of two enzymes, glyoxalase 1 and 2, which in humans are encoded by the genes GLO1 and HAGH, respectively. Glyoxalase 1 and 2 catalyze the detoxification of reactive alpha-oxoaldehydes such as glyoxal and methylglyoxal, which are particularly damaging components of carbonyl stress. Here, we investigated the role of the glyoxalase system in schizophrenia by performing association analyses of common genetic variants (n=12) in GLO1 and HAGH in a Japanese sample consisting of 2012 schizophrenia patients and 2170 healthy controls. We detected a nominally significant association with schizophrenia (p=0.020) of rs11859266, a SNP in the intronic region of HAGH. However, rs11859266 did not survive multiple testing (empirical p=0.091). The variants in HAGH, rs11859266 and rs3743852, showed significant associations with schizophrenia in males at allelic and genotype levels, which remained persistent after multiple testing with the exception of rs3743852 for the genotype model. We further measured the mRNA expression of both genes in postmortem brain, but did not detect any changes in transcript expression levels between case and control samples or in sex-specific comparisons. Therefore, our findings suggest that an explanation of elevated carbonyl stress in a substantial part (reported as ~20%) of patients with schizophrenia will require the examination of a much larger cohort to detect risk alleles with weak effect size and/or other risk factors.

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.

A case of lichen planus pemphigoides with autoantibodies to the NC16a and C-terminal domains of BP180 and to desmoglein-1

Lichen planus pemphigoides (LPP) is a rare autoimmune blistering disease that occurs in association with lichen planus (LP). This report describes a 59-year-old Japanese female patient with LPP. The patient first showed LP lesions on her hands, and subsequently developed bullae on her extremities and erosions of the oral mucosa. The patient's serum was positive for IgG autoantibodies against the BP180 NC16a domain, the BP180 C-terminal domain and desmoglein-1. However, a serum sampled one and a half years before the diagnosis of LPP was negative for autoantibodies against BP180 NC16a and BP180 C-terminal domains. These findings strongly suggest that the damage to the basal cells in the LP lesions exposed a sequestered antigen or formed neoantigens, leading to the production of pathogenic autoantibodies for LPP. Most of the previous cases of LPP have produced autoantibodies to the NC16a domain of BP180. This is the first case in which autoantibodies to the C-terminal domain of BP180 were detected. The oral mucosal symptoms in this case may have been caused by autoantibodies to the BP180 C-terminal domain.

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.

Sequencing and expression analyses of the synaptic lipid raft adapter gene PAG1 in schizophrenia

Disruption of synaptic networks has been advocated in the pathogenesis of psychiatric diseases like schizophrenia. The majority of synaptic proteins involved in neuronal communications are localized in lipid rafts. These rafts form the platform for coordinating neuronal signal transduction, by clustering interacting partners. The PAG1 protein is a transmembrane adaptor protein in the lipid raft signaling cluster that regulates Src family kinases (SFKs), a convergent point for multiple pathways regulating N-methyl-D-aspartate (NMDA) receptors. Reports of de novo missense mutations in PAG1 and SFK mediated reductions in tyrosine phosphorylation of NMDA receptor subunit proteins in schizophrenia patients, point to a putative role in schizophrenia pathogenesis. To evaluate this, we resequenced the entire coding region of PAG1 in Japanese schizophrenia patients (n = 1,140) and controls (n = 1,140). We identified eight missense variants, of which four were previously unreported. Case-control genetic association analysis of these variants in a larger cohort (n = 4,182) showed neither a statistically significant association of the individual variants with schizophrenia, nor any increased burden of the rare alleles in the patient group. Expression levels of PAG1 in post-mortem brain samples from schizophrenia patients and controls also showed no significant differences. To assess the precise role of PAG1 in schizophrenia, future studies with larger sample sizes are needed.

Lack of association of EGR2 variants with bipolar disorder in Japanese population

The early growth response gene 2 (EGR2) has been recently reported to be associated with bipolar disorder in the Korean population. However replication studies in independent cohorts of same and different ethnicities are essential for establishing the credibility of a genotype-phenotype association. With this notion, in the present study we have performed a replication study of the reported association of SNPs in EGR2 in a case-control study comprising of 867 unrelated Japanese bipolar disorder patients and 895 age-, sex- and ethnicity-matched controls. Results showed no significant differences in allele and genotype frequencies of EGR2 SNPs between bipolar disorder patients and controls and also in a sex-stratified genetic analysis. The haplotype and meta-analyses also showed no significant association with bipolar disorder. In conclusion, this is the first replication study of the previously reported association of EGR2 with bipolar disorder in a larger sample set and the results showed that the EGR2 gene is unlikely to contribute to the susceptibility of bipolar disorder in a Japanese cohort.

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.

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.

Enzymes in the glutamate-glutamine cycle in the anterior cingulate cortex in postmortem brain of subjects with autism

BACKGROUND

Accumulating evidence suggests that dysfunction in the glutamatergic system may underlie the pathophysiology of autism. The anterior cingulate cortex (ACC) has been implicated in autism as well as in glutamatergic neurotransmission. We hypothesized that alterations in the glutamate-glutamine cycle in the ACC might play a role in the pathophysiology of autism.

METHODS

We performed Western blot analyses for the protein expression levels of enzymes in the glutamate-glutamine cycle, including glutamine synthetase, kidney-type glutaminase, liver-type glutaminase, and glutamate dehydrogenases 1 and 2, in the ACC of postmortem brain of individuals with autism (n = 7) and control subjects (n = 13).

RESULTS

We found that the protein levels of kidney-type glutaminase, but not those of the other enzymes measured, in the ACC were significantly lower in subjects with autism than in controls.

CONCLUSION

The results suggest that reduced expression of kidney-type glutaminase may account for putative alterations in glutamatergic neurotransmission in the ACC in autism.

Different critical perinatal periods and hypothalamic sites of oestradiol action in the defeminisation of luteinising hormone surge and lordosis capacity in the rat

Female rats show a gonadotrophin-releasing hormone (GnRH)/luteinising hormone (LH) surge in the presence of a preovulatory level of oestrogen, whereas males do not because of brain defeminisation during the developmental period by perinatal oestrogen converted from androgen. The present study aimed to identify the site(s) of oestrogen action and the critical period for defeminising the mechanism regulating the GnRH/LH surge. Animals given perinatal treatments, such as steroidal manipulations, brain local implantation of oestradiol (E(2) ) or administration of an NMDA antagonist, were examined for their ability to show an E(2) -induced LH surge at adulthood. Lordosis behaviour was examined to compare the mechanisms defeminising the GnRH/LH surge and sexual behaviour. A single s.c. oestradiol-benzoate administration on either the day before birth (E21), the day of birth (D0) or day 5 (D5) postpartum completely abolished the E(2) -induced LH surge at adulthood in female rats, although the same treatment did not inhibit lordosis. Perinatal castration on E21 or D0 partially rescued the E2-induced LH surge in genetically male rats, whereas castration from E21 to D5 totally rescued lordosis. Neonatal E(2) implantation in the anterior hypothalamus including the anteroventral periventricular nucleus (AVPV)/preoptic area (POA) abolished the E(2) -induced LH surge in female rats, whereas E(2) implantation in the mid and posterior hypothalamic regions had no inhibitory effect on the LH surge. Lordosis was not affected by neonatal E(2) implantation in any hypothalamic regions. In male rats, neonatal NMDA antagonist treatment rescued lordosis but not the LH surge. Taken together, these results suggest that an anterior hypothalamic region such as the AVPV/POA region is a perinatal site of oestrogen action where the GnRH/LH regulating system is defeminised to abolish the oestrogen-induced surge. The mechanism for defeminisation of the GnRH/LH surge system might be different from that of sexual behaviour, in terms of the site(s) of oestrogen action and critical period, as well as the neurotransmitter system involved.

Microglial activation in young adults with autism spectrum disorder

CONTEXT

A growing body of evidence suggests that aberrant immunologic systems underlie the pathophysiologic characteristics of autism spectrum disorder (ASD). However, to our knowledge, no information is available on the patterns of distribution of microglial activation in the brain in ASD.

OBJECTIVES

To identify brain regions associated with excessively activated microglia in the whole brain, and to examine similarities in the pattern of distribution of activated microglia in subjects with ASD and control subjects.

DESIGN

Case-control study using positron emission tomography and a radiotracer for microglia--[11C](R)-(1-[2-chrorophynyl]-N-methyl-N-[1-methylpropyl]-3 isoquinoline carboxamide) ([11C](R)-PK11195).

SETTING

Subjects recruited from the community.

PARTICIPANTS

Twenty men with ASD (age range, 18-31 years; mean [SD] IQ, 95.9 [16.7]) and 20 age- and IQ-matched healthy men as controls. Diagnosis of ASD was made in accordance with the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised.

MAIN OUTCOME MEASURES

Regional brain [11C](R)-PK11195 binding potential as a representative measure of microglial activation.

RESULTS

The [11C](R)-PK11195 binding potential values were significantly higher in multiple brain regions in young adults with ASD compared with those of controls (P < .05, corrected). Brain regions with increased binding potentials included the cerebellum, midbrain, pons, fusiform gyri, and the anterior cingulate and orbitofrontal cortices. The most prominent increase was observed in the cerebellum. The pattern of distribution of [11C](R)-PK11195 binding potential values in these brain regions of ASD and control subjects was similar, whereas the magnitude of the [11C](R)-PK11195 binding potential in the ASD group was greater than that of controls in all regions.

CONCLUSIONS

Our results indicate excessive microglial activation in multiple brain regions in young adult subjects with ASD. The similar distribution pattern of regional microglial activity in the ASD and control groups may indicate augmented but not altered microglial activation in the brain in the subjects with ASD.

Seasonal variations of neuromotor development by 14 months of age: Hamamatsu Birth Cohort for mothers and children (HBC Study)

The present study aimed at investigating whether neuromotor development, from birth to 14 months of age, shows seasonal, cyclic patterns in association with months of birth. Study participants were 742 infants enrolled in the Hamamatsu Birth Cohort (HBC) Study and followed-up from birth to the 14th month of age. Gross motor skills were assessed at the ages of 6, 10, and 14 months, using Mullen Scales of Early Learning. The score at each assessment was regressed onto a trigonometric function of months of birth, with an adjustment for potential confounders. Gross motor scores at the 6th and 10th months showed significant 1-year-cycle variations, peaking among March- and April-born infants, and among February-born infants, respectively. Changes in gross motor scores between the 10th and 14th months also showed a cyclic variation, peaking among July- and August-born infants. Due to this complementary effect, gross motor scores at the 14th month did not show seasonality. Neuromotor development showed cyclic seasonality during the first year of life. The effects brought about by month of birth disappeared around 1 year of age, and warmer months seemed to accelerate the neuromotor development.

Downregulation of the expression of mitochondrial electron transport complex genes in autism brains

Mitochondrial dysfunction (MtD) and abnormal brain bioenergetics have been implicated in autism, suggesting possible candidate genes in the electron transport chain (ETC). We compared the expression of 84 ETC genes in the post-mortem brains of autism patients and controls. Brain tissues from the anterior cingulate gyrus, motor cortex, and thalamus of autism patients (n = 8) and controls (n = 10) were obtained from Autism Tissue Program, USA. Quantitative real-time PCR arrays were used to quantify gene expression. We observed reduced expression of several ETC genes in autism brains compared to controls. Eleven genes of Complex I, five genes each of Complex III and Complex IV, and seven genes of Complex V showed brain region-specific reduced expression in autism. ATP5A1 (Complex V), ATP5G3 (Complex V) and NDUFA5 (Complex I) showed consistently reduced expression in all the brain regions of autism patients. Upon silencing ATP5A1, the expression of mitogen-activated protein kinase 13 (MAPK13), a p38 MAPK responsive to stress stimuli, was upregulated in HEK 293 cells. This could have been induced by oxidative stress due to impaired ATP synthesis. We report new candidate genes involved in abnormal brain bioenergetics in autism, supporting the hypothesis that mitochondria, critical for neurodevelopment, may play a role in autism.

Brain region-specific altered expression and association of mitochondria-related genes in autism

BACKGROUND

Mitochondrial dysfunction (MtD) has been observed in approximately five percent of children with autism spectrum disorders (ASD). MtD could impair highly energy-dependent processes such as neurodevelopment, thereby contributing to autism. Most of the previous studies of MtD in autism have been restricted to the biomarkers of energy metabolism, while most of the genetic studies have been based on mutations in the mitochondrial DNA (mtDNA). Despite the mtDNA, most of the proteins essential for mitochondrial replication and function are encoded by the genomic DNA; so far, there have been very few studies of those genes. Therefore, we carried out a detailed study involving gene expression and genetic association studies of genes related to diverse mitochondrial functions.

METHODS

For gene expression analysis, postmortem brain tissues (anterior cingulate gyrus (ACG), motor cortex (MC) and thalamus (THL)) from autism patients (n=8) and controls (n=10) were obtained from the Autism Tissue Program (Princeton, NJ, USA). Quantitative real-time PCR arrays were used to quantify the expression of 84 genes related to diverse functions of mitochondria, including biogenesis, transport, translocation and apoptosis. We used the delta delta Ct (∆∆Ct) method for quantification of gene expression. DNA samples from 841 Caucasian and 188 Japanese families were used in the association study of genes selected from the gene expression analysis. FBAT was used to examine genetic association with autism.

RESULTS

Several genes showed brain region-specific expression alterations in autism patients compared to controls. Metaxin 2 (MTX2), neurofilament, light polypeptide (NEFL) and solute carrier family 25, member 27 (SLC25A27) showed consistently reduced expression in the ACG, MC and THL of autism patients. NEFL (P = 0.038; Z-score 2.066) and SLC25A27 (P = 0.046; Z-score 1.990) showed genetic association with autism in Caucasian and Japanese samples, respectively. The expression of DNAJC19, DNM1L, LRPPRC, SLC25A12, SLC25A14, SLC25A24 and TOMM20 were reduced in at least two of the brain regions of autism patients.

CONCLUSIONS

Our study, though preliminary, brings to light some new genes associated with MtD in autism. If MtD is detected in early stages, treatment strategies aimed at reducing its impact may be adopted.

Vldlr overexpression causes hyperactivity in rats

BACKGROUND

Reelin regulates neuronal positioning in cortical brain structures and neuronal migration via binding to the lipoprotein receptors Vldlr and Lrp8. Reeler mutant mice display severe brain morphological defects and behavioral abnormalities. Several reports have implicated reelin signaling in the etiology of neurodevelopmental and psychiatric disorders, including autism, schizophrenia, bipolar disorder, and depression. Moreover, it has been reported that VLDLR mRNA levels are increased in the post-mortem brain of autistic patients.

METHODS

We generated transgenic (Tg) rats overexpressing Vldlr, and examined their histological and behavioral features.

RESULTS

Spontaneous locomotor activity was significantly increased in Tg rats, without detectable changes in brain histology. Additionally, Tg rats tended to show performance deficits in the radial maze task, suggesting that their spatial working memory was slightly impaired. Thus, Vldlr levels may be involved in determining locomotor activity and memory function.

CONCLUSIONS

Unlike reeler mice, patients with neurodevelopmental or psychiatric disorders do not show striking neuroanatomical aberrations. Therefore, it is notable, from a clinical point of view, that we observed behavioral phenotypes in Vldlr-Tg rats in the absence of neuroanatomical abnormalities.