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In humans, circulating blood cells such as platelets are being increasingly used as a readily available and minimally invasive biospecimen to determine mitochondrial respiratory function. Here, we set out to determine the influence of sample preparation, assay buffer composition, and instrumental platform, on the respiratory function of platelets isolated from human blood.Approximately 50 mL of whole blood was collected from healthy adults (n=16) following an overnight (>12 hr.) fast. Platelets were immediately isolated from whole blood by centrifugation. Respiratory function was assayed in intact and permeabilized platelets using an Oxygraph-2K (O2K) high-resolution respirometer (Oroboros Instruments). Respiratory function was assayed in intact platelets suspended in either culture (RPMI) or respiration (MIR05) media (both supplemented with 5 mM glucose, 1 mM pyruvate and 2 mM glutamine), or the participants own plasma. Respiratory function was also assayed in digitonin-permeabilized platelets suspended in both RPMI and MIR05. In addition, respiratory function was determined in intact platelets using a Seahorse Extra-Cellular Flux analyzer (XFe) in RPMI buffer containing 5 mM glucose, 1 mM pyruvate and 2 mM glutamine.In intact platelets assayed in suspension using an O2K, routine and ATP-linked respiration were 35 and 34% greater in cells assayed in RPMI compared to MIR05, respectively (P Supported by USDA-ARS Project 6026-51000-012-06S, NIH 5P20GM109096-07 and 5R35GM142744-02. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

OBJECTIVES: The obesity epidemic is continuing to grow in the United States and world for past two decades. There is a link between obesity and chronic diseases development such as diabetes, cardiovascular disease, certain types of cancer and liver diseases. Previously, we reported that obesity caused a significant increase liver steatosis and feeding soy protein isolate (SPI) reduced liver steatosis. The mechanism of SPI protection against liver steatosis is less known. We hypothesize that soy protein diet will reduce development of liver steatosis caused by obesity in part by changing methylation status. The objective of the present study was to investigate the effects of SPI feeding on liver metabolic methylation status using obese zucker rat model. METHODS: After one week of acclimation, five weeks old female lean and obese Zucker rats (n = 8/group) were randomly fed AIN-93-G diet with either casein (CAS as control) or SPI as source of protein for 22 weeks. Rats were weighted twice per week. Liver sample metabolites concentrations were measured using HPLC with Electrochemical Detection and LC-MS. RESULTS: Our results shows that; 1) obesity increased body weight significantly (P

Background and purpose Thoracic (chemo)radiation therapy is increasingly administered with tyrosine kinase inhibitors (TKI). While TKI have adverse effects on the heart, it is unknown whether combination with other cancer therapies causes enhanced toxicity. We used an animal model to investigate whether radiation and sunitinib interact in their effects on the heart. Material and methods Male Sprague–Dawley rats received local heart irradiation (9Gy per day, 5days). Oral sunitinib (8 or 15mg/kg bodyweight per day) started on day 1 of irradiation and continued for 2weeks. Cardiac function was examined with echocardiography. Cardiac remodeling, cell death, left ventricular (LV) oxidative stress markers, mitochondrial morphology and mitochondrial permeability transition pore (mPTP) opening were assessed. Results Cardiac diameter, stroke volume, and LV volume, mass and anterior wall thickness increased in time, but only in the vehicle group. Sunitinib reduced LV inner diameter and volume in systole, which were counteracted by radiation. Sunitinib and radiation showed enhanced effects on mitochondrial morphology and mPTP opening, but not on cardiac troponin I, mast cell numbers or markers of oxidative stress. Conclusions This study found no early enhanced effects of radiation and sunitinib on cardiac function or structure. Long-term effects remain to be determined.

DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation-proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ((56)Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or (56)Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with (56)Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and expression of repetitive elements may serve as early biomarkers of exposure to space radiation.

Background Currently there is no test for pregnant mothers that can predict the probability of having a child that will be diagnosed with autism spectrum disorder (ASD). Recent estimates indicate that if a mother has previously had a child with ASD, the risk of having a second child with ASD is ∼18.7% (High Risk) whereas the risk of ASD in the general population is ∼1.7% (Low Risk). Methods In this study, metabolites of the folate-dependent transmethylation and transsulfuration biochemical pathways of pregnant mothers were measured to determine whether or not the risk of having a child with autism could be predicted by her metabolic profile. Pregnant mothers who have had a child with autism before were separated into two groups based on the diagnosis of their child whether the child had autism (ASD) or not (TD). Then these mothers were compared to a group of control mothers who have not had a child with autism before. A total of 107 mothers were in the High Risk category and 25 mothers in the Low Risk category. The High Risk category was further separated into 29 mothers in the ASD group and 78 mothers in the TD group. Results The metabolic results indicated that among High Risk mothers, it was not possible to predict an autism pregnancy outcome. However, the metabolic profile was able to predict with approximately 90% sensitivity and specificity whether a mother fell into the High Risk group (18.7% risk) or Low Risk group (1.7% risk). Conclusions Based upon these measurements it is not possible to determine during a pregnancy if a child will be diagnosed with ASD by age 3. However, differences in the folate-dependent transmethylation and transsulfuration metabolites are indicative of the risk level (High Risk of 18.7% vs. Low Risk of 1.7%) of the mother for having a child with ASD.

The prevalence of the overweight and obesity is on the rise worldwide. Obesity can increase the risk of certain cancers and liver steatosis development. Previously, we reported that obesity increased liver steatosis in a mammary tumor model, but little is known about the effects of obesity in the liver in regard to global DNA methylation, DNA damage, and oxidative/nitrosative stress. Using a mammary tumor model, we investigated the effects of obesity on oxidative stress and DNA reaction. Five-week-old lean and obese female rats were used. At 50 days of age, all rats received 7,12-dimethylbenz(α)anthracene (DMBA) and were sacrificed 155 days later. HPLC with electrochemical and ultraviolet detection and LC-MS were used. Obesity caused higher (p < 0.0004) methionine levels, had no effect (p < 0.055) on SAM levels, caused lower (p < 0.0005) SAH levels, caused higher (p < 0.0005) SAM/SAH ratios, and increased (p < 0.02) global DNA methylation. Levels of free reduced GSH were not significantly lower (p < 0.08), but free oxidized GSSG was higher (p < 0.002) in obese rats. The GSH/GSSG ratio was lower (p < 0.0001), and oxidized guanosine was higher (p < 0.002) in DNA of obese rats compared to lean rats. Obesity caused significant oxidative/nitrosative stress, oxidative DNA damage, and change of DNA methylation pattern in the liver, and these changes may contribute to the development of liver steatosis in breast cancer models.

Long interspersed nuclear elements-1 (LINE-1 or L1) are mobile DNA sequences that are capable of duplication and insertion (retrotransposition) within the genome. Recently, retrotransposition of L1 was shown to occur within human brain leading to somatic mosaicism in hippocampus and cerebellum. Because unregulated L1 activity can promote genomic instability and mutagenesis, multiple mechanisms including epigenetic chromatin condensation have evolved to effectively repress L1 expression. Nonetheless, L1 expression has been shown to be increased in patients with Rett syndrome and schizophrenia. Based on this evidence and our reports of oxidative stress and epigenetic dysregulation in autism cerebellum, we sought to determine whether L1 expression was increased in autism brain. The results indicated that L1 expression was significantly elevated in the autism cerebellum but not in BA9, BA22, or BA24. The binding of repressive MeCP2 and histone H3K9me3 to L1 sequences was significantly lower in autism cerebellum suggesting that relaxation of epigenetic repression may have contributed to increased expression. Further, the increase in L1 expression was inversely correlated with glutathione redox status consistent with reports indicating that L1 expression is increased under pro-oxidant conditions. Finally, the expression of transcription factor FOXO3, sensor of oxidative stress, was significantly increased and positively associated with L1 expression and negatively associated with glutathione redox status. While these novel results are an important first step, future understanding of the contribution of elevated L1 expression to neuronal CNVs and genomic instability in autism will depend on emerging cell-specific genomic technologies, a challenge that warrants future investigation.

Research into the metabolic phenotype of autism has been relatively unexplored despite the fact that metabolic abnormalities have been implicated in the pathophysiology of several other neurobehav- ioral disorders. Plasma biomarkers of oxidative stress have been reported in autistic children; however, intra- cellular redox status has not yet been evaluated. Lym- phoblastoid cells (LCLs) derived from autistic children and unaffected controls were used to assess relative concentrations of reduced glutathione (GSH) and oxi- dized disulfide glutathione (GSSG) in cell extracts and isolated mitochondria as a measure of intracellular redox capacity. The results indicated that the GSH/ GSSG redox ratio was decreased and percentage oxi- dized glutathione increased in both cytosol and mito- chondria in the autism LCLs. Exposure to oxidative stress via the sulfhydryl reagent thimerosal resulted in a greater decrease in the GSH/GSSG ratio and increase in free radical generation in autism compared to con- trol cells. Acute exposure to physiological levels of nitric oxide decreased mitochondrial membrane poten- tial to a greater extent in the autism LCLs, although GSH/GSSG and ATP concentrations were similarly decreased in both cell lines. These results suggest that the autism LCLs exhibit a reduced glutathione reserve capacity in both cytosol and mitochondria that may compromise antioxidant defense and detoxification ca- pacity under prooxidant conditions.—James, S. J., Rose, S., Melnyk, S., Jernigan, S., Blossom, S., Pavliv, O., Gaylor, D.W. Cellular and mitochondrial glutathione re- dox imbalance in lymphoblastoid cells derived from chil- dren with autism. FASEB J. 23, 000-000 (2009)

Background: Metabolic abnormalities and targeted treatment trials have been reported for several neurobehavioral disorders but are relatively understudied in autism. Objective: The objective of this study was to determine whether or not treatment with the metabolic precursors, methylcobalamin and folinic acid, would improve plasma concentrations of transmethylation/transsulfuration metabolites and glutathione redox status in autistic children. Design: In an open-label trial, 40 autistic children were treated with 75 μg/kg methylcobalamin (2 times/wk) and 400 μg folinic acid (2 times/d) for 3 mo. Metabolites in the transmethylation/transsulfuration pathway were measured before and after treatment and compared with values measured in age-matched control children. Results: The results indicated that pretreatment metabolite concentrations in autistic children were significantly different from values in the control children. The 3-mo intervention resulted in significant increases in cysteine, cysteinylglycine, and glutathione concentrations (P < 0.001). The oxidized disulfide form of glutathione was decreased and the glutathione redox ratio increased after treatment (P < 0.008). Although mean metabolite concentrations were improved significantly after intervention, they remained below those in unaffected control children. Conclusion: The significant improvements observed in transmethylation metabolites and glutathione redox status after treatment suggest that targeted nutritional intervention with methylcobalamin and folinic acid may be of clinical benefit in some children who have autism. This trial was registered at clinicaltrials.gov as NCT00692315.

The age-associated decline in cellular antioxidant defenses and resultant accumulation of DNA damage in central nervous system has been mechanistically implicated in the etiology and pathogenesis of neurodegenerative diseases. Neurons possess a high metabolic activity and are especially vulnerable to the long-term effects of continuous exposure to endogenous reactive oxygen species. It is well recognized that adequate availability of essential nutrients involved in cellular one-carbon metabolism is essential for normal brain development and function. Additionally, the synthesis of the primary low-molecular cellular antioxidant glutathione is inter-dependently linked to one-carbon metabolic pathway. Thus, any aberrant disruptions in one-carbon metabolism can result in potentially deleterious effects including cell death as a result of an imbalance in the cellular redox state. Hence, in the present study, we examined the long-term effects of a folate/methyl-deficient (FMD) diet on cellular antioxidant defenses and DNA damage in the rat brain. Feeding male Fisher 344 rats a FMD diet resulted in perturbations in the levels of one-carbon metabolites along with induction of oxidative stress and oxidative DNA damage in the brain. This was evidenced by a decrease in the reduced oxidized/glutathione ratio, imbalance of cellular antioxidant defense system; specifically, altered activity and expression of antioxidant enzymes Mn-containing superoxide dismutase (Mn-SOD), catalase, and glutathione peroxidase (GPX), increased accumulation of oxidative DNA lesions, 8-hydroxydeoxyguanosine (8-OH-dG) and DNA single-strand breaks, even in the presence of increased expression of critical DNA repair genes apurinic/apyrimidinic endonuclease 1 (Apex1) and DNA polymerase beta (Polbeta), and apoptosis in the brains of folate/methyl-deficient rats. These results indicate that chronic methyl group deficiency leads to an imbalance in cellular antioxidant defense systems, increased oxidative stress, and apoptosis. Any of these events may compromise normal central nervous system function and contribute to the development of various neurological, behavioral, and neurocognitive dysfunctions.

Epidemiological studies showed that obese women have higher mortality rates from all cancers including breast cancer. Previously we reported that obesity effects methylation and create higher oxida...

The conserved oligomeric Golgi (COG) complex is an evolutionarily conserved peripheral membrane oligomeric protein complex that is involved in intra-Golgi protein trafficking. The COG complex is composed of eight subunits that are located in two lobes; Lobe A contains COG1-4, and Lobe B is composed of COG5-8. Both in vivo and in vitro protein-protein interaction techniques were applied to characterize interactions between individual COG subunits. In vitro assays revealed binary interactions between Cog2p and Cog3p, Cog2p and Cog4p, and Cog6p and Cog8p and a strong interaction between Cog5p and Cog7p. The two-hybrid assay confirmed these findings and revealed that Cog1p interacted with subunits from both lobes of the complex. Antibodies to COG subunits were utilized to determine the protein levels and membrane association of COG subunits in yeast delta cog1-8 mutants. As a result, we created a model of the protein-protein interactions within the yeast COG complex and proposed that Cog1p is a bridging subunit between the two COG lobes. In support of this hypothesis, we have demonstrated that Cog1p is required for the stable association between two COG subcomplexes.

Epigenetic mechanisms regulate programmed gene expression during prenatal neurogenesis and serve as a mediator between genetics and environment in postnatal life. The recent discovery of 5-hydroxymethylcytosine (5-hmC), with highest concentration in the brain, has added a new dimension to epigenetic regulation of neurogenesis and the development of complex behavior disorders. Here, we take a candidate gene approach to define the role 5-hmC in Engrailed-2 (EN-2) gene expression in the autism cerebellum. The EN-2 homeobox transcription factor, previously implicated in autism, is essential for normal cerebellar patterning and development. We previously reported EN-2 overexpression associated with promoter DNA hypermethylation in the autism cerebellum but because traditional DNA methylation methodology cannot distinguish 5-methylcytosine (5-mC) from 5-hmC, we now extend our investigation by quantifying global and gene-specific 5-mC and 5-hmC. Globally, 5-hmC was significantly increased in the autism cerebellum and accompanied by increases in the expression of de novo methyltransferases DNMT3A and DNMT3B, ten-eleven translocase genes TET1 and TET3, and in 8-oxo-deoxyguanosine (8-oxo-dG) content, a marker of oxidative DNA damage. Within the EN-2 promoter, there was a significant positive correlation between 5-hmC content and EN-2 gene expression. Based on reports of reduced MeCP2 affinity for 5-hmC, MeCP2 binding studies in the EN-2 promoter revealed a significant decrease in repressive MeCP2 binding that may contribute to the aberrant overexpression of EN-2. Because normal cerebellar development depends on perinatal EN-2 downregulation, the sustained postnatal overexpression suggests that a critical window of cerebellar development may have been missed in some individuals with autism with downstream developmental consequences. Epigenetic regulation of the programmed on-off switches in gene expression that occur at birth and during early brain development warrants further investigation.

There is increasing recognition that mitochondrial dysfunction is associated with the autism spectrum disorders. However, little attention has been given to the etiology of mitochondrial dysfunction or how mitochondrial abnormalities might interact with other physiological disturbances associated with autism, such as oxidative stress. In the current study we used respirometry to examine reserve capacity, a measure of the mitochondrial ability to respond to physiological stress, in lymphoblastoid cell lines (LCLs) derived from children with autistic disorder (AD) as well as age and gender-matched control LCLs. We demonstrate, for the first time, that LCLs derived from children with AD have an abnormal mitochondrial reserve capacity before and after exposure to increasingly higher concentrations of 2,3-dimethoxy-1,4-napthoquinone (DMNQ), an agent that increases intracellular reactive oxygen species (ROS). Specifically, the AD LCLs exhibit a higher reserve capacity at baseline and a sharper depletion of reserve capacity when ROS exposure is increased, as compared to control LCLs. Detailed investigation indicated that reserve capacity abnormalities seen in AD LCLs were the result of higher ATP-linked respiration and maximal respiratory capacity at baseline combined with a marked increase in proton leak respiration as ROS was increased. We further demonstrate that these reserve capacity abnormalities are driven by a subgroup of eight (32%) of 25 AD LCLs. Additional investigation of this subgroup of AD LCLs with reserve capacity abnormalities revealed that it demonstrated a greater reliance on glycolysis and on uncoupling protein 2 to regulate oxidative stress at the inner mitochondria membrane. This study suggests that a significant subgroup of AD children may have alterations in mitochondrial function which could render them more vulnerable to a pro-oxidant microenvironment derived from intrinsic and extrinsic sources of ROS such as immune activation and pro-oxidant environmental toxicants. These findings are consistent with the notion that AD is caused by a combination of genetic and environmental factors.

Treatments targeting metabolic abnormalities in children with autism are limited. Previously we reported that a nutritional treatment significantly improved glutathione metabolism in children with autistic disorder. In this study we evaluated changes in adaptive behaviors in this cohort and determined whether such changes are related to changes in glutathione metabolism. Thirty-seven children diagnosed with autistic disorder and abnormal glutathione and methylation metabolism were treated with twice weekly 75 µg/Kg methylcobalamin and twice daily 400 µg folinic acid for 3 months in an open-label fashion. The Vineland Adaptive Behavior Scale (VABS) and glutathione redox metabolites were measured at baseline and at the end of the treatment period. Over the treatment period, all VABS subscales significantly improved with an average effect size of 0.59, and an average improvement in skills of 7.7 months. A greater improvement in glutathione redox status was associated with a greater improvement in expressive communication, personal and domestic daily living skills, and interpersonal, play-leisure, and coping social skills. Age, gender, and history of regression did not influence treatment response. The significant behavioral improvements observed and the relationship between these improvements to glutathione redox status suggest that nutritional interventions targeting redox metabolism may benefit some children with autism.

Free oxygen and free nitrogen radicals, commonly named as reactive oxygen species (ROS) and reactive nitrogen species (RNS) play an important role in cancer promotion. The cumulative effect of ROS/RNS termed oxidative and nitrosative stress is commonly seen in the development of several cancers. Obesity has been also linked with the risk of development of various cancers, including breast cancer. DHEA is a dietary supplement used as an anti-cancer agent and anti-obesity supplement. Previously, we reported that obese rats fed DHEA had lower body weight gain and developed no mammary tumor in DMBA model. The effect of DHEA on development of oxidative/nitrosative stress is not known. The objectives of this study were to investigate the possible mechanism of DHEA tumor protection by determining the DHEA effects on serum concentration of methylation cycle metabolites, oxidative and nitrosative stress biomarkers. Twenty (20) six-week-old obese female Zucker rats were randomly assigned ad libitum to water and a diet of either chow as a control diet or chow with the addition of DHEA at a concentration of 6 g/kg of chow as a DHEA diet. All rats were orally gavaged at age 50 days with 65 mg DMBA/kg body weight and were sacrificed 155 days later. Serum concentration of Methionine, S-sdenosylmethionine (SAM), S-adenosylhomocysteine (SAH), homocysteine, free reduced glutathione (fGSH), oxidized glutathione (GSSG), nitroglutathione (GSNO), free Cysteine, Cystine and 3-nitroTyrosine (3NT) were measured by HPLC method with electrochemical detection or LC-MS method. There were no significant differences in serum concentration of fGSH between control and DHEA fed-rats. However, DHEA-fed rats had lower (P Citation Format: Reza Hakkak, Soheila Korourian, Teresa Evans, Oleksandra Pavliv, Stepan Melnyk. Effects of Dehydroepiandrosterone (DHEA) treatment on serum methylation, oxidative and nitrosative stress biomarkers in an obesity model of mammary carcinogenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3459.

Oxidative stress and abnormal DNA methylation have been implicated in the pathophysiology of autism. We investigated the dynamics of an integrated metabolic pathway essential for cellular antioxidant and methylation capacity in 68 children with autism, 54 age-matched control children and 40 unaffected siblings. The metabolic profile of unaffected siblings differed significantly from case siblings but not from controls. Oxidative protein/DNA damage and DNA hypomethylation (epigenetic alteration) were found in autistic children but not paired siblings or controls. These data indicate that the deficit in antioxidant and methylation capacity is specific for autism and may promote cellular damage and altered epigenetic gene expression. Further, these results suggest a plausible mechanism by which pro-oxidant environmental stressors may modulate genetic predisposition to autism.

The modulation of the redox microenvironment is an important regulator of immune cell activation and proliferation. To investigate immune cell redox status in autism we quantified the intracellular glutathione redox couple (GSH/GSSG) in resting peripheral blood mononuclear cells (PBMCs), activated monocytes and CD4 T cells and the extracellular cysteine/cystine redox couple in the plasma from 43 children with autism and 41 age-matched control children. Resting PBMCs and activated monocytes from children with autism exhibited significantly higher oxidized glutathione (GSSG) and percent oxidized glutathione equivalents and decreased glutathione redox status (GSH/GSSG). In activated CD4 T cells from children with autism, the percent oxidized glutathione equivalents were similarly increased, and GSH and GSH/GSSG were decreased. In the plasma, both glutathione and cysteine redox ratios were decreased in autistic compared to control children. Consistent with decreased intracellular and extracellular redox status, generation of free radicals was significantly elevated in lymphocytes from the autistic children. These data indicate primary immune cells from autistic children have a more oxidized intracellular and extracellular microenvironment and a deficit in glutathione-mediated redox/antioxidant capacity compared to control children. These results suggest that the loss of glutathione redox homeostasis and chronic oxidative stress may contribute to immune dysregulation in autism.

The biologic basis of autism is complex and is thought to involve multiple and variable gene-environment interactions. While the logical focus has been on the affected child, the impact of maternal genetics on intrauterine microenvironment during pivotal developmental windows could be substantial. Folate-dependent one carbon metabolism is a highly polymorphic pathway that regulates the distribution of one-carbon derivatives between DNA synthesis (proliferation) and DNA methylation (cell-specific gene expression and differentiation). These pathways are essential to support the programmed shifts between proliferation and differentiation during embryogenesis and organogenesis. Maternal genetic variants that compromise intrauterine availability of folate derivatives could alter fetal cell trajectories and disrupt normal neurodevelopment. In this investigation, the frequency of common functional polymorphisms in the folate pathway was investigated in a large population-based sample of autism case-parent triads. In case-control analysis, a significant increase in the reduced folate carrier (RFC1) G allele frequency was found among case mothers, but not among fathers or affected children. Subsequent log linear analysis of the RFC1 A80G genotype within family trios revealed that the maternal G allele was associated with a significant increase in risk of autism whereas the inherited genotype of the child was not. Further, maternal DNA from the autism mothers was found to be significantly hypomethylated relative to reference control DNA. Metabolic profiling indicated that plasma homocysteine, adenosine, and S-adenosylhomocyteine were significantly elevated among autism mothers consistent with reduced methylation capacity and DNA hypomethylation. Together, these results suggest that the maternal genetics/epigenetics may influence fetal predisposition to autism.

Radiation-induced heart disease (RIHD) is a common and sometimes severe late side effect of radiation therapy for intrathoracic and chest wall tumors. We have previously shown that local heart irradiation in a rat model caused prolonged changes in mitochondrial respiration and increased susceptibility to mitochondrial permeability transition pore (mPTP) opening. Because tocotrienols are known to protect against oxidative stress-induced mitochondrial dysfunction, in this study, we examined the effects of tocotrienols on radiation-induced alterations in mitochondria, and structural and functional manifestations of RIHD. Male Sprague-Dawley rats received image-guided localized X irradiation to the heart to a total dose of 21 Gy. Twenty-four hours before irradiation, rats received a tocotrienol-enriched formulation or vehicle by oral gavage. Mitochondrial function and mitochondrial membrane parameters were studied at 2 weeks and 28 weeks after irradiation. In addition, cardiac function and histology were examined at 28 weeks. A single oral dose of the tocotrienol-enriched formulation preserved Bax/Bcl2 ratios and prevented mPTP opening and radiation-induced alterations in succinate-driven mitochondrial respiration. Nevertheless, the late effects of local heart irradiation pertaining to myocardial function and structure were not modified. Our studies suggest that a single dose of tocotrienols protects against radiation-induced mitochondrial changes, but these effects are not sufficient against long-term alterations in cardiac function or remodeling.

The elucidation of epigenetic alterations in the autism brain has potential to provide new insights into the molecular mechanisms underlying abnormal gene expression in this disorder. Given strong evidence that engrailed-2 (EN-2) is a developmentally expressed gene relevant to cerebellar abnormalities and autism, the epigenetic evaluation of this candidate gene was undertaken in 26 case and control post-mortem cerebellar samples. Assessments included global DNA methylation, EN-2 promoter methylation, EN-2 gene expression and EN-2 protein levels. Chromatin immunoprecipitation was used to evaluate trimethylation status of histone H3 lysine 27 (H3K27) associated with gene downregulation and histone H3 lysine 4 (H3K4) associated with gene activation. The results revealed an unusual pattern of global and EN-2 promoter region DNA hypermethylation accompanied by significant increases in EN-2 gene expression and protein levels. Consistent with EN-2 overexpression, histone H3K27 trimethylation mark in the EN-2 promoter was significantly decreased in the autism samples relative to matched controls. Supporting a link between reduced histone H3K27 trimethylation and increased EN-2 gene expression, the mean level of histone H3K4 trimethylation was elevated in the autism cerebellar samples. Together, these results suggest that the normal EN-2 downregulation that signals Purkinje cell maturation during late prenatal and early-postnatal development may not have occurred in some individuals with autism and that the postnatal persistence of EN-2 overexpression may contribute to autism cerebellar abnormalities.

Despite increasing evidence of oxidative stress in the pathophysiology of autism, most studies have not evaluated biomarkers within specific brain regions, and the functional consequences of oxidative stress remain relatively understudied. We examined frozen samples from the cerebellum and temporal cortex (Brodmann area 22 (BA22)) from individuals with autism and unaffected controls (n=15 and n=12 per group, respectively). Biomarkers of oxidative stress, including reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione redox/antioxidant capacity (GSH/GSSG), were measured. Biomarkers of oxidative protein damage (3-nitrotyrosine; 3-NT) and oxidative DNA damage (8-oxo-deoxyguanosine; 8-oxo-dG) were also assessed. Functional indicators of oxidative stress included relative levels of 3-chlorotyrosine (3-CT), an established biomarker of a chronic inflammatory response, and aconitase activity, a biomarker of mitochondrial superoxide production. Consistent with previous studies on plasma and immune cells, GSH and GSH/GSSG were significantly decreased in both autism cerebellum (P