Identification and quantification of DNA N6-methyladenine modification in mammals: A challenge to modern analytical technologies.

DNA N6-methyladenine modification (6mA) is a predominant epigenetic mark in prokaryotes but rarely present in multicellular metazoa. The analytical technologies have been developed for sensitive detection of 6mA, including ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS) and single molecule real-time sequencing (SMRTseq). However, it remains challenging to detect 6mA at global level and/or in the context of sequence in multicellular metazoa (including mammals). This mini-review brings insights into current dilemma and potential solutions for the identification and quantifications of 6mA in mammals.

The benefits of expressive writing among newly diagnosed mainland Chinese breast cancer patients.

The study aimed to evaluate the effects of an expressive writing intervention on quality of life (QoL) among mainland Chinese breast cancer patients. A total of 118 Chinese breast cancer patients were randomly assigned to one of four groups: a cancer-facts writing condition (CTL group), an emotional disclosure writing condition (EMO group), a self-regulation writing condition (SR group), or a neutral control condition with no writing tasks (CON group). QoL was assessed by FACT-B at baseline, 3-, and 6-month follow-ups. A repeated measure analysis of variance revealed significant effects of time (F = 13.9, P < 0.001, η2 = 0.20) and the time × group interaction (F = 3.5, P < 0.01, η2 = 0.08) on QoL. Residualized change models showed that the CTL, EMO and SR groups reported higher levels of QoL than the CON group at the 6-month follow-up. The EMO group had a higher level of QoL than the SR group. The CTL group had higher level of physical well-being compared to the SR group. Mainland Chinese breast cancer patients shortly after diagnosis benefit from expressive writing. They benefited more from cancer-facts and emotional disclosure compared to self-regulation. The study indicated that the impact of expressive writing may differ due to stage of cancer survivorship, social, and cultural context.

The detrimental effects of ambivalence over emotional expression on well-being among Mainland Chinese breast cancer patients: Mediating role of perceived social support.

OBJECTIVE: Recent research has documented the harmful effects of ambivalence over emotional expression (AEE) on psychological well-being, but few studies to date have examined AEE among Mainland Chinese breast cancer patients, an ethnic group that prioritizes emotion restraint to preserve social harmony. The present study examined the relationship between AEE and well-being (viz, anxious and depressive symptoms and quality of life) and evaluated perceived social support as a potential mediator of this relationship in a sample of Mainland Chinese breast cancer patients. METHODS: Three hundred twenty-seven Chinese breast cancer patients recruited from Weifang, China, completed a self-reported questionnaire containing the Ambivalence over Emotional Expression Questionnaire (AEQ), the Medical Outcomes Study Social Support Scale (MOS-SSS), the Self-rating Anxiety Scale (SAS), the Self-rating Depression Scale (SDS), and the Functional Assessment of Cancer Therapy-Breast (FACT-B). RESULTS: Overall, Mainland Chinese breast cancer patients endorsed high levels of AEE. A series of mediation analyses revealed perceived social support served as a partial mediator of the relationship between AEE and well-being. Specifically, AEE was associated with lower perceived social support (ßs = -.13, P < .001), which in turn, was associated with greater anxious symptoms (ß = .23, P < .001), depressive symptoms (ß = .20, P < .001) and lower quality of life (ß = -.30, P < .001). CONCLUSIONS: The harmful relationship between AEE and well-being is partially explained by reduced social support. Psychosocial interventions that facilitate emotional disclosure without harming social harmony may be culturally effective for mainland Chinese breast cancer patients.

Microglial Pruning of Synapses in the Prefrontal Cortex During Adolescence.

Exaggerated synaptic elimination in the prefrontal cortex (PFC) during adolescence has been suggested to contribute to the neuropathological changes of schizophrenia. Recent data indicate that microglia (MG) sculpt synapses during early postnatal development. However, it is not known if MG contribute to the structural maturation of the PFC, which has a protracted postnatal development. We determined if MG are involved in developmentally specific synapse elimination in the PFC, focusing on adolescence. Layer 5 PFC pyramidal cells (PCs) were intracellularly filled with Lucifer Yellow for dendritic spine measurements in postnatal day (P) 24, P30, P35, P39, and P50 rats. In the contralateral PFC we evaluated if MG engulfed presynaptic (glutamatergic) and postsynaptic (dendritic spines) elements. Dendritic spine density increased from P24 to P35, when spine density peaked. There was a significant increase in MG engulfment of spines at P39 relative to earlier ages; this subsided by P50. MG also phagocytosed presynaptic glutamatergic terminals. These data indicate that MG transiently prune synapses of PFC PCs during adolescence, when the symptoms of schizophrenia typically first appear. An increase in MG-mediated synaptic remodeling of PFC PCs may contribute to the structural changes observed in schizophrenia.

Connecting imaging mass spectrometry and magnetic resonance imaging-based anatomical atlases for automated anatomical interpretation and differential analysis.

Imaging mass spectrometry (IMS) is a molecular imaging technology that can measure thousands of biomolecules concurrently without prior tagging, making it particularly suitable for exploratory research. However, the data size and dimensionality often makes thorough extraction of relevant information impractical. To help guide and accelerate IMS data analysis, we recently developed a framework that integrates IMS measurements with anatomical atlases, opening up opportunities for anatomy-driven exploration of IMS data. One example is the automated anatomical interpretation of ion images, where empirically measured ion distributions are automatically decomposed into their underlying anatomical structures. While offering significant potential, IMS-atlas integration has thus far been restricted to the Allen Mouse Brain Atlas (AMBA) and mouse brain samples. Here, we expand the applicability of this framework by extending towards new animal species and a new set of anatomical atlases retrieved from the Scalable Brain Atlas (SBA). Furthermore, as many SBA atlases are based on magnetic resonance imaging (MRI) data, a new registration pipeline was developed that enables direct non-rigid IMS-to-MRI registration. These developments are demonstrated on protein-focused FTICR IMS measurements from coronal brain sections of a Parkinson's disease (PD) rat model. The measurements are integrated with an MRI-based rat brain atlas from the SBA. The new rat-focused IMS-atlas integration is used to perform automated anatomical interpretation and to find differential ions between healthy and diseased tissue. IMS-atlas integration can serve as an important accelerator in IMS data exploration, and with these new developments it can now be applied to a wider variety of animal species and modalities. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

Cortical hierarchy governs rat claustrocortical circuit organization.

The claustrum is a telencephalic gray matter structure with various proposed functions, including sensory integration and attentional allocation. Underlying these concepts is the reciprocal connectivity of the claustrum with most, if not all, areas of the cortex. What remains to be elucidated to inform functional hypotheses further is whether a pattern exists in the strength of connectivity between a given cortical area and the claustrum. To this end, we performed a series of retrograde neuronal tract tracer injections into rat cortical areas along the cortical processing hierarchy, from primary sensory and motor to frontal cortices. We observed that the number of claustrocortical projections increased as a function of processing hierarchy; claustrum neurons projecting to primary sensory cortices were scant and restricted in distribution across the claustrum, whereas neurons projecting to the cingulate cortex were densely packed and more evenly distributed throughout the claustrum. This connectivity pattern suggests that the claustrum may preferentially subserve executive functions orchestrated by the cingulate cortex. J. Comp. Neurol. 525:1347-1362, 2017. © 2016 Wiley Periodicals, Inc.

Astragalosides promote angiogenesis via vascular endothelial growth factor and basic fibroblast growth factor in a rat model of myocardial infarction.

The aim of the present study was to evaluate the effect of astragalosides (ASTs) on angiogenesis, as well as the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) following myocardial infarction (MI). MI was induced in rats by ligation of the left coronary artery. Twenty­four hours after surgery, the rats were divided into low­dose, high­dose, control and sham surgery groups (n=8 per group). The low­ and high­dose groups were treated with ASTs (2.5 and 10 mg/kg/day, respectively, via intraperitoneal injection), while, the control and sham surgery group rats received saline. Serum levels, and mRNA and protein expression levels of VEGF and bFGF, as well as the microvessel density (MVD) were determined four weeks post­treatment. Twenty­four hours post­surgery, VEGF and bFGF serum levels were observed to be comparable between the groups; while at four weeks, the VEGF and bFGF levels were higher in the AST­treated rats (P<0.01). Similarly, VEGF and bFGF mRNA and protein expression levels were higher following AST treatment (P<0.05). No difference in VEGF mRNA expression between the low­ and high­dose groups was noted, however, an increase in the bFGF expression levels was detected in the high­dose group. Newly generated blood vessels were observed following MI, with a significant increase in MVD observed in the AST­treated groups (P<0.05). AST promotes angiogenesis of the heart and increases VEGF and bFGF expression levels. Thus, it is hypothesized that increased VEGF and bFGF levels may contribute to the AST­induced increase in angiogenesis in rat models of MI.

Genetic inhibition of CaMKII in dorsal striatal medium spiny neurons reduces functional excitatory synapses and enhances intrinsic excitability.

Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is abundant in striatal medium spiny neurons (MSNs). CaMKII is dynamically regulated by changes in dopamine signaling, as occurs in Parkinson's disease as well as addiction. Although CaMKII has been extensively studied in the hippocampus where it regulates excitatory synaptic transmission, relatively little is known about how it modulates neuronal function in the striatum. Therefore, we examined the impact of selectively overexpressing an EGFP-fused CaMKII inhibitory peptide (EAC3I) in striatal medium spiny neurons (MSNs) using a novel transgenic mouse model. EAC3I-expressing cells exhibited markedly decreased excitatory transmission, indicated by a decrease in the frequency of spontaneous excitatory postsynaptic currents (sEPSCs). This decrease was not accompanied by changes in the probability of release, levels of glutamate at the synapse, or changes in dendritic spine density. CaMKII regulation of the AMPA receptor subunit GluA1 is a major means by which the kinase regulates neuronal function in the hippocampus. We found that the decrease in striatal excitatory transmission seen in the EAC3I mice is mimicked by deletion of GluA1. Further, while CaMKII inhibition decreased excitatory transmission onto MSNs, it increased their intrinsic excitability. These data suggest that CaMKII plays a critical role in setting the excitability rheostat of striatal MSNs by coordinating excitatory synaptic drive and the resulting depolarization response.

Dystrophic dendrites in prefrontal cortical pyramidal cells of dopamine D1 and D2 but not D4 receptor knockout mice.

Recent data indicate that cortical dopamine denervation results in dystrophic changes in the dendrites of pyramidal cells, including decreases in dendritic spine density and length. However, it is not known if the loss of signaling through specific dopamine receptors subserves these dendritic changes. We examined the dendritic structure of layer V pyramidal cells in the prefrontal cortex of D(1), D(2), and D(4) dopamine receptor null mutant mice and their wild-type littermates. Decreased basal dendritic length and spine density were observed in the D(1) knockout mice. Similarly, a decrease in basal dendritic spine density was uncovered in the D(2) knockout mice relative to wild-type littermates. No changes in any dendritic parameter were observed in the D(4) knockout mice. These observations suggest that the dystrophic changes observed in prefrontal cortical pyramidal cell dendrites are due to loss of signaling through D(1) and possibly D(2) receptors. The current data also suggest that caution should be exercised in the interpretation of behavioral, physiological, and biochemical studies of the prefrontal cortex in dopamine receptor knockout mice.

Fat embolism syndromes following liposuction.

Fat embolism syndrome (FES) after liposuction is likely a life-threatening disorder, though its incidence is low. The three chief clinical manifestations include respiratory insufficiency, cerebral involvement, and petechial rash. Although FES is a multisystem disorder, the most seriously affected organs are the lungs, brain, cardiavascular system, and skin. Many laboratory findings are characteristic but nonspecific. The pathogenesis of FES after liposuction has been looked at both mechanically and biochemically. Diagnosis is difficult; Gurd and Wilson's diagnostic criteria based on clinical examination is still extensively used in clinics at present. There is no specific therapy for FES after liposuction for the moment, so prevention, early diagnosis, and supportive therapies are important. In this article we discuss the clinical presentation, pathogensis, and current methods to prevent FES and, if possible, ways to treat this complication.

Dopamine depletion of the prefrontal cortex induces dendritic spine loss: reversal by atypical antipsychotic drug treatment.

Dystrophic changes in dendrites of cortical neurons are present in several neuro-psychiatric disorders, including schizophrenia. The mechanisms that account for dendritic changes in the prefrontal cortex (PFC) in schizophrenia are unclear. Cognitive deficits in schizophrenia have been linked to compromised cortical dopamine function, and the density of the PFC dopamine innervation is decreased in schizophrenia. We determined if 6-hydroxydopamine lesions of the ventral tegmental area that disrupt the PFC dopamine innervation cause dystrophic changes in cortical neurons. Three weeks post-operatively we observed a marked decrease in basal dendritic length and spine density of layer V pyramidal cells in the prelimbic cortex; no change was seen in neurons of the motor cortex. We then examined rats in which the PFC dopamine innervation was lesioned and 3 weeks later were started on chronic treatment with an atypical (olanzapine) or typical (haloperidol) antipsychotic drug. Olanzapine but not haloperidol reversed lesion-induced changes in PFC pyramidal cell dendrites. These data suggest that dopamine regulates dendritic structure in PFC neurons. Moreover, the findings are consistent with a decrease in cortical dopaminergic tone contributing to the pathological changes in the cortex of schizophrenia, and suggest that the progressive cortical loss in schizophrenia may be slowed or reversed by treatment with atypical antipsychotic drugs.

Effects of antipsychotic drugs on neurogenesis in the forebrain of the adult rat.

The generation of new cells in the adult mammalian brain may significantly modify pathophysiological processes in neuropsychiatric disorders. We examined the ability of chronic treatment with the antipsychotic drugs (APDs) olanzapine and haloperidol to increase the number and survival of newly generated cells in the prefrontal cortex (PFC) and striatal complex of adult male rats. Animals were treated with olanzapine or haloperidol for 3 weeks and then injected with 5-bromo-2'-deoxyuridine (BrdU) to label mitotic cells. Half of the animals continued on the same APD for two more weeks after BrdU challenge, with the other half receiving vehicle during this period. Olanzapine but not haloperidol significantly increased both the total number and density of BrdU-labeled cells in the PFC and dorsal striatum; no effect was observed in the nucleus accumbens. Continued olanzapine treatment after the BrdU challenge did not increase the survival of newly generated cells. The newly generated cells in the PFC did not express the neuronal marker NeuN. Despite the significant increase in newly generated cells in the PFC of olanzapine-treated rats, the total number of these cells is low, suggesting that the therapeutic effects of atypical APD treatment may not be due to the presence of newly generated cells that have migrated to the cortex.

The blockade by phencyclidine of glutamate-induced intracellular calcium increase in cultured neocortical neurons.

A calcium imaging technique combined with a confocal laser scanning microscope (CLSM) was applied to investigate the effects of phencyclidine (PCP) on glutamate-induced calcium increases in same group of primary cultured neocortical neurons. Non-N-methyl-D-aspartate (NMDA) receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) alone did not significantly alter glutamate-induced changes of fluorescence (89.6%), while addition of PCP greatly blocked increases in fluorescence to 32.6% of the glutamate response. Competitive NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (APV) alone and the addition of PCP reduced glutamate responses to 30.5% and 21.2%, respectively. These data clearly demonstrate that the neuropharmacological properties of PCP may function through its blockade of the NMDA receptor.

A shift in information flow between prefrontal cortex and the ventral tegmental area in methamphetamine-sensitized rats.

We examined the effects of long-term methamphetamine (MAP) administration to rats on locomotor traces and reward-seeking behavior that was evaluated through ventral tegmental intracranial self-stimulation (ICSS). Furthermore, using the directed coherence (DCOH) EEG analysis method, correlation of prefrontal cortical and ventral tegmental EEGs was investigated in terms of the direction of information transmission. The results showed a transition from 'mixed type' behavior to 'fixed type' behavior during long-term MAP treatment, accompanied by a gradually diminished rate of ICSS and increased reward threshold. Correlating to these changes, a dominant information flow from ventral tegmental area (VTA) to prefrontal cortex (PFC) was observed after long-term MAP administration. Together with our previously reported finding of reciprocal information flow between PFC and VTA in MAP-induced hyperactive and stereotyped behavior, the present results indicate that information flow and its direction may be useful in explaining the neuronal substrates mediating development of behavioral sensitization. The predominant information flow from the VTA to PFC that occurs with sensitization supports recent speculations concerning impulsivity in drug addiction.