Wide-ranging DNA methylation differences of primary trophoblast cell populations and derived cell lines: implications and opportunities for understanding trophoblast function

Difficulties associated with long-term culture of primary trophoblasts have proven to be a major hurdle in their functional characterization. In order to circumvent this issue, several model cell lines have been established over many years using a variety of different approaches. Due to their differing origins, gene expression profiles and behaviour in vitro, different model lines have been utilized to investigate specific aspects of trophoblast biology. However, generally speaking, the molecular mechanisms underlying functional differences remain unclear. In this study, we profiled genome-scale DNA methylation in primary first trimester trophoblast cells and seven commonly used trophoblast-derived cell lines in an attempt to identify functional pathways differentially regulated by epigenetic modification in these cells. We identified a general increase in DNA promoter methylation levels in four choriocarcinoma (CCA)-derived lines and transformed HTR-8/SVneo cells, including hypermethylation of several genes regularly seen in human cancers, while other differences in methylation were noted in genes linked to immune responsiveness, cell morphology, development and migration across the different cell populations. Interestingly, CCA-derived lines show an overall methylation profile more similar to unrelated solid cancers than to untransformed trophoblasts, highlighting the role of aberrant DNA methylation in CCA development and/or long-term culturing. Comparison of DNA methylation and gene expression in CCA lines and cytotrophoblasts revealed a significant contribution of DNA methylation to overall expression profile. These data highlight the variability in epigenetic state between primary trophoblasts and cell models in pathways underpinning a wide range of cell functions, providing valuable candidate pathways for future functional investigation in different cell populations. This study also confirms the need for caution in the interpretation of data generated from manipulation of such pathways in vitro.     

Attachment mental states and inferred pathways of development in borderline personality disorder: a study using the Adult Attachment Interview

We report the outcome of an investigation on how specific attachment states of mind and corresponding risk factors related to different DSM Axis I comorbidities in subjects with BPD. Mental representations of attachment in four BPD sub-groups (BPD and Anxiety/Mood Disorders, BPD and Substance Use and Abuse Disorders, BPD and Alcohol Use and Abuse Disorders, and BPD and Eating Disorders) were assessed in 140 BPD subjects using the Adult Attachment Interview (AAI). In addition to the global attachment picture in which Insecure organized (Dismissing 51% and Enmeshed 35%) and Insecure disorganized categories (40%) were overrepresented, significant differences in attachment category were found between the four BPD sub-groups. Axis I comorbidities corresponded with attachment features on the internalizing/externalizing functioning dimension of the disorder. Furthermore, specific constellations of inferred developmental antecedents and attachment states of mind corresponded differentially with the BPD sub-groups. Implications for developmental research and clinical nosology are discussed.     

The role of prefrontal cortex in visuo-spatial planning: a repetitive TMS study

The visuo-spatial planning process is based on an “opportunistic” combination of heuristics and strategies, carried out in small units during the execution of plans. In order to investigate the functional role of the prefrontal cortex in heuristic switching, 42 healthy controls performed a labyrinth crossing task (the Maps Test). During this computerized version of the Travelling Salesperson Problem, subjects had to decide which order of locations optimizes total travel time and distance. This task was performed with and without 1 Hz repetitive transcranial magnetic stimulation (rTMS), which exerts an inhibitory action on the targeted area, applied during the task over bilateral frontal sites (active stimulation) and parieto-occipital site (sham stimulation). Only repetitive bilateral rTMS over F3 and F4 significantly decreased the number of strategies with changes of heuristics, and increased the number of movements required to solve the task. This behaviour contrasts with the performance of healthy subjects in the planning task, but is consistent with the performance of frontal traumatic brain injury patients. The results indicate that, in a visuo-spatial problem-solving task, the prefrontal cortex is involved in the switching between heuristics during the execution of a plan.     

Perceptual Sensitivity to High-Frequency Interaural Time Differences Created by Rustling Sounds

Interaural time differences (ITDs) can be used to localize sounds in the horizontal plane. ITDs can be extracted from either the fine structure of low-frequency sounds or from the envelopes of high-frequency sounds. Studies of the latter have included stimuli with periodic envelopes like amplitude-modulated tones or transposed stimuli, and high-pass filtered Gaussian noises. Here, four experiments are presented investigating the perceptual relevance of ITD cues in synthetic and recorded “rustling” sounds. Both share the broad long-term power spectrum with Gaussian noise but provide more pronounced envelope fluctuations than Gaussian noise, quantified by an increased waveform fourth moment, W. The current data show that the JNDs in ITD for band-pass rustling sounds tended to improve with increasing W and with increasing bandwidth when the sounds were band limited. In contrast, no influence of W on JND was observed for broadband sounds, apparently because of listeners' sensitivity to ITD in low-frequency fine structure, present in the broadband sounds. Second, it is shown that for high-frequency rustling sounds ITD JNDs can be as low as 30 μs. The third result was that the amount of dominance for ITD extraction of low frequencies decreases systematically with increasing amount of envelope fluctuations. Finally, it is shown that despite the exceptionally good envelope ITD sensitivity evident with high-frequency rustling sounds, minimum audible angles of both synthetic and recorded high-frequency rustling sounds in virtual acoustic space are still best when the angular information is mediated by interaural level differences.     

Neurodegeneration induced by complex I inhibition in a cellular model of familial amyotrophic lateral sclerosis

G93A Cu/Zn superoxide dismutase (SOD1), a human mutant SOD1 associated with familial amyotrophic lateral sclerosis, increased the toxicity of the mitochondrial toxin rotenone in the NSC-34 motoneuronal cell line. G93ASOD1 cells died more than untransfected and wild-type SOD1 cells after 6 and 24h exposure to 12.5 microM rotenone. Biparametric flow cytometry showed that rotenone induced rapid hyperpolarization of mitochondrial membrane potential (deltapsi(m)) in all the cell lines, followed by depolarization, and then by cell death. However, G93ASOD1 mitochondria were significantly more likely to shift from a hyperpolarized to a depolarized condition, and within the still viable cell population there was a higher proportion with depolarized mitochondria, a condition that can be envisaged as a commitment to cell death. ATP, which is needed to prevent loss of deltapsi(m), decreased more rapidly and to a greater extent in rotenone-treated G93ASOD1 cells than in the untransfected and wtSOD1cells. In all the cell lines, 1h after rotenone exposure, mitochondrial hyperpolarization was accompanied by the formation of a comparable amount of reactive oxygen species. However, G93ASOD1 cells reached the highest reactive oxygen species level since their basal level was higher than in untransfected and wild-type SOD1 cells. Our findings indicate that the mutant protein G93ASOD1 enhances the vulnerability of motor neurons to rotenone by mechanism(s) involving oxidative stress and perturbed mitochondrial homeostasis. This suggests that motor neurons from individuals carrying the mutant G93ASOD1 are at greater risk of death after inhibition of the electron transport chain.     

A RARE CASE OF ADENOVIRAL FULMINANT HEPATIC NECROSIS AFTER CHEMOTHERAPY

The authors report a rare case of fulminant adenoviral hepatic necrosis occurring after chemotherapy in a patient with a second relapse of acute myeloid leukemia. The literature is reviewed and the a role of rapid viral diagnosis in the clinical management of this complication is discussed. A 10-year-old girl with relapsed acute myeloid leukemia after allogeneic bone marrow transplant underwent re-induction chemotherapy with high-dose cytosine arabinoside and amsacrine. During induction she developed diarrhea and a marked coagulopathy, followed by fulminant hepatic failure and acute pre-renal failure. She rapidly deteriorated and died. A limited autopsy was performed. Adenovirus type 5 was cultured from ante mortem clinical samples and detected by polymerase chain reaction in postmortem samples of heart blood, lung, trachea, spleen, and liver. At autopsy, the liver demonstrated massive hepatic necrosis with positive immunofluorescence for adenovirus. Electron microscopy demonstrated intranuclear inclusions, typical of adenovirus. There was no evidence of pneumonia. Adenovirus can cause fulminant hepatic necrosis following chemotherapy in a nontransplant setting. If adenoviral disease is suspected, appropriate rapid viral studies should be undertaken, because early intervention with ribavirin or cidofovir may prevent rapid fulminant progression. Further studies on the role of antiviral therapy in this setting are warranted.     

Operationalising ‘sexual orientation’ in routine data collection and equality monitoring in the UK

New legal provisions and regulatory practices in the UK have afforded protection against discrimination for sexual orientation minorities and conferred rights similar to those of heterosexually partnered couples. In addition, sexual orientation has been recognised as one of the main equality strands in new equality legislation and equality governance. Government departments and statutory and other organisations now face the need to collect equal opportunities and other data on these groups to monitor compliance. However, there has been little track record in the UK of collecting data on this dimension, resulting in issues of definition, categorisation, sample size and potential measurement error having to be addressed from a negligible evidence base. Limited survey data indicate significant problems relating to item non‐response and misreporting, reflecting wider concerns about the sensitivity of the data and disclosure. Given that sexual orientation is on track to be mainstreamed in the context of workforce recruitment and service delivery, a strategy across government and other sectors is needed to pool expertise and establish a shared evidence base and stock of good practice.