Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination.

During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. Despite these critical functions, crossover frequency varies extensively within and between species. Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained elusive. Using natural Arabidopsis thaliana accessions, we identified two major recombination quantitative trait loci (rQTLs) that explain 56.9% of crossover variation in Col×Ler F2 populations. We mapped rQTL1 to semidominant polymorphisms in HEI10, which encodes a conserved ubiquitin E3 ligase that regulates crossovers. Null hei10 mutants are haploinsufficient, and, using genome-wide mapping and immunocytology, we show that transformation of additional HEI10 copies is sufficient to more than double euchromatic crossovers. However, heterochromatic centromeres remained recombination-suppressed. The strongest HEI10-mediated crossover increases occur in subtelomeric euchromatin, which is reminiscent of sex differences in Arabidopsis recombination. Our work reveals that HEI10 naturally limits Arabidopsis crossovers and has the potential to influence the response to selection.

Mucopolysaccharidosis (MPS IIIA) mice have increased lung compliance and airway resistance, decreased diaphragm strength, and no change in alveolar structure.

Mucopolysaccharidosis type IIIA (MPS IIIA) is characterized by neurological and skeletal pathologies caused by reduced activity of the lysosomal hydrolase, sulfamidase, and the subsequent primary accumulation of undegraded heparan sulfate (HS). Respiratory pathology is considered secondary in MPS IIIA and the mechanisms are not well understood. Changes in the amount, metabolism, and function of pulmonary surfactant, the substance that regulates alveolar interfacial surface tension and modulates lung compliance and elastance, have been reported in MPS IIIA mice. Here we investigated changes in lung function in 20-wk-old control and MPS IIIA mice with a closed and open thoracic cage, diaphragm contractile properties, and potential parenchymal remodeling. MPS IIIA mice had increased compliance and airway resistance and reduced tissue damping and elastance compared with control mice. The chest wall impacted lung function as observed by an increase in airway resistance and a decrease in peripheral energy dissipation in the open compared with the closed thoracic cage state in MPS IIIA mice. Diaphragm contractile forces showed a decrease in peak twitch force, maximum specific force, and the force-frequency relationship but no change in muscle fiber cross-sectional area in MPS IIIA mice compared with control mice. Design-based stereology did not reveal any parenchymal remodeling or destruction of alveolar septa in the MPS IIIA mouse lung. In conclusion, the increased storage of HS which leads to biochemical and biophysical changes in pulmonary surfactant also affects lung and diaphragm function, but has no impact on lung or diaphragm structure at this stage of the disease.NEW & NOTEWORTHY Heparan sulfate storage in the lungs of mucopolysaccharidosis type IIIA (MPS IIIA) mice leads to changes in lung function consistent with those of an obstructive lung disease and includes an increase in lung compliance and airway resistance and a decrease in tissue elastance. In addition, diaphragm muscle contractile strength is reduced, potentially further contributing to lung function impairment. However, no changes in parenchymal lung structure were observed in mice at 20 wk of age.

MSH2 shapes the meiotic crossover landscape in relation to interhomolog polymorphism in Arabidopsis.

During meiosis, DNA double-strand breaks undergo interhomolog repair to yield crossovers between homologous chromosomes. To investigate how interhomolog sequence polymorphism affects crossovers, we sequenced multiple recombinant populations of the model plant Arabidopsis thaliana. Crossovers were elevated in the diverse pericentromeric regions, showing a local preference for polymorphic regions. We provide evidence that crossover association with elevated diversity is mediated via the Class I crossover formation pathway, although very high levels of diversity suppress crossovers. Interhomolog polymorphism causes mismatches in recombining molecules, which can be detected by MutS homolog (MSH) mismatch repair protein heterodimers. Therefore, we mapped crossovers in a msh2 mutant, defective in mismatch recognition, using multiple hybrid backgrounds. Although total crossover numbers were unchanged in msh2 mutants, recombination was remodelled from the diverse pericentromeres towards the less-polymorphic sub-telomeric regions. Juxtaposition of megabase heterozygous and homozygous regions causes crossover remodelling towards the heterozygous regions in wild type Arabidopsis, but not in msh2 mutants. Immunostaining showed that MSH2 protein accumulates on meiotic chromosomes during prophase I, consistent with MSH2 regulating meiotic recombination. Our results reveal a pro-crossover role for MSH2 in regions of higher sequence diversity in A. thaliana.

A Paradigm in Immunochemistry, Revealed by Monoclonal Antibodies to Spatially Distinct Epitopes on Syntenin-1.

Syntenin-1 is an essential multi-functional adaptor protein, which has multiple roles in membrane trafficking and exosome biogenesis, as well as scaffolding interactions with either the actin cytoskeleton or focal adhesions. However, how this functional multiplicity relates to syntenin-1 distribution in different endosome compartments or other intracellular locations and its underlying involvement in cancer pathogenesis have yet to be fully defined. To help facilitate the investigation of syntenin-1 biology, we developed two specific monoclonal antibodies (Synt-2C6 and Synt-3A11) to spatially distinct linear sequence epitopes on syntenin-1, which were each designed to be unique at the six-amino acid level. These antibodies produced very different intracellular staining patterns, with Synt-2C6 detecting endosomes and Synt-3A11 producing a fibrillar staining pattern suggesting a cytoskeletal localisation. Treatment of cells with Nocodazole altered the intracellular localisation of Synt-3A11, which was consistent with the syntenin-1 protein interacting with microtubules. In prostate tissue biopsies, Synt-3A11 defined atrophy and early-stage prostate cancer, whereas Synt-2C6 only showed minimal interaction with atrophic tissue. This highlights a critical need for site-specific antibodies and a knowledge of their reactivity to define differential protein distributions, interactions and functions, which may differ between normal and malignant cells.

Modification of meiotic recombination by natural variation in plants.

Meiosis is a specialized cell division that produces haploid gametes required for sexual reproduction. During the first meiotic division, homologous chromosomes pair and undergo reciprocal crossing over, which recombines linked sequence variation. Meiotic recombination frequency varies extensively both within and between species. In this review, we will examine the molecular basis of meiotic recombination rate variation, with an emphasis on plant genomes. We first consider cis modification caused by polymorphisms at the site of recombination, or elsewhere on the same chromosome. We review cis effects caused by mismatches within recombining joint molecules, the effect of structural hemizygosity, and the role of specific DNA sequence motifs. In contrast, trans modification of recombination is exerted by polymorphic loci encoding diffusible molecules, which are able to modulate recombination on the same and/or other chromosomes. We consider trans modifiers that act to change total recombination levels, hotspot locations, or interactions between homologous and homeologous chromosomes in polyploid species. Finally, we consider the significance of genetic variation that modifies meiotic recombination for adaptation and evolution of plant species.

Self-regulation of the anterior insula: Reinforcement learning using real-time fMRI neurofeedback.

The anterior insula (AI) plays a key role in affective processing, and insular dysfunction has been noted in several clinical conditions. Real-time functional MRI neurofeedback (rtfMRI-NF) provides a means of helping people learn to self-regulate activation in this brain region. Using the Blood Oxygenated Level Dependant (BOLD) signal from the right AI (RAI) as neurofeedback, we trained participants to increase RAI activation. In contrast, another group of participants was shown 'control' feedback from another brain area. Pre- and post-training affective probes were shown, with subjective ratings and skin conductance response (SCR) measured. We also investigated a reward-related reinforcement learning model of rtfMRI-NF. In contrast to the controls, we hypothesised a positive linear increase in RAI activation in participants shown feedback from this region, alongside increases in valence ratings and SCR to affective probes. Hypothesis-driven analyses showed a significant interaction between the RAI/control neurofeedback groups and the effect of self-regulation. Whole-brain analyses revealed a significant linear increase in RAI activation across four training runs in the group who received feedback from RAI. Increased activation was also observed in the caudate body and thalamus, likely representing feedback-related learning. No positive linear trend was observed in the RAI in the group receiving control feedback, suggesting that these data are not a general effect of cognitive strategy or control feedback. The control group did, however, show diffuse activation across the putamen, caudate and posterior insula which may indicate the representation of false feedback. No significant training-related behavioural differences were observed for valence ratings, or SCR. In addition, correlational analyses based on a reinforcement learning model showed that the dorsal anterior cingulate cortex underpinned learning in both groups. In summary, these data demonstrate that it is possible to regulate the RAI using rtfMRI-NF within one scanning session, and that such reward-related learning is mediated by the dorsal anterior cingulate.

Prostate cell lines as models for biomarker discovery: performance of current markers and the search for new biomarkers.

BACKGROUND: Prostate cancer cell lines have been used in the search for biomarkers that are suitable for prostate cancer diagnosis. Unfortunately, many cell line studies have only involved single cell lines, partially characterized cell lines or were performed without controls, and this may have been detrimental to effective biomarker discovery. We have analyzed a panel of prostate cancer and nonmalignant control cell lines using current biomarkers and then investigated a set of prospective endosomal and lysosomal proteins to search for new biomarkers. METHODS: Western blotting was used to define the amount of protein and specific molecular forms in cell extracts and culture media from a panel of nonmalignant (RWPE-1, PNT1a, PNT2) and prostate cancer (22RV1, CaHPV10, DU-145, LNCaP) cell lines. Gene expression was determined by qRT-PCR. RESULTS: HPV-18 transfected cell lines displayed a different pattern of protein and gene expression when compared to the other cell lines examined, suggesting that these cell lines may not be the most optimal for prostate cancer biomarker discovery. There was an increased amount of prostatic acid phosphatase and kallikrein proteins in LNCaP cell extracts and culture media, but variable amounts of these proteins in other prostate cancer cell lines. There were minimal differences in the amounts of lysosomal proteins detected in prostate cancer cells and culture media, but two endosomal proteins, cathepsin B and acid ceramidase, had increased gene and protein expression, and certain molecular forms showed increased secretion from prostate cancer cells (P ≤ 0.05). LIMP-2 gene and protein expression was significantly increased in prostate cancer compared to nonmalignant cell lines (P ≤ 0.05). CONCLUSIONS: While the existing prostate cancer biomarkers and lysosomal proteins investigated here were not able to specifically differentiate between a panel of nonmalignant and prostate cancer cell lines, endosomal proteins showed some discriminatory capacity. LIMP-2 is a critical regulator of endosome biogenesis and the increased expression observed in prostate cancer cells indicated that other endosome related proteins may also be upregulated and could be investigated as novel biomarkers.

Neonatal gene therapy with a gamma retroviral vector in mucopolysaccharidosis VI cats.

Mucopolysaccharidosis (MPS) VI is due to a deficiency in the activity of N-acetylgalactosamine 4-sulfatase (4S), also known as arylsulfatase B. Previously, retroviral vector (RV)-mediated neonatal gene therapy reduced the clinical manifestations of MPS I and MPS VII in mice and dogs. However, sulfatases require post-translational modification by sulfatase-modifying factors. MPS VI cats were injected intravenously (i.v.) with a gamma RV-expressing feline 4S, resulting in 5 ± 3 copies of RV per 100 cells in liver. Liver and serum 4S activity were 1,450 ± 1,720 U/mg (26-fold normal) and 107 ± 60 U/ml (13-fold normal), respectively, and were directly proportional to the liver 4S protein levels for individual cats. This study suggests that sulfatase-modifying factor (SUMF) activity in liver was sufficient to result in active enzyme despite overexpression of 4S. RV-treated MPS VI cats achieved higher body weights and longer appendicular skeleton lengths, had reduced articular cartilage erosion, and reduced aortic valve thickening and aortic dilatation compared with untreated MPS VI cats, although cervical vertebral bone lengths were not improved. This demonstrates that therapeutic expression of a functional sulfatase protein can be achieved with neonatal gene therapy using a gamma RV, but some aspects of bone disease remain difficult to treat.

Lysosomal storage disease: revealing lysosomal function and physiology.

The discovery over five decades ago of the lysosome, as a degradative organelle and its dysfunction in lysosomal storage disorder patients, was both insightful and simple in concept. Here, we review some of the history and pathophysiology of lysosomal storage disorders to show how they have impacted on our knowledge of lysosomal biology. Although a significant amount of information has been accrued on the molecular genetics and biochemistry of lysosomal storage disorders, we still do not fully understand the mechanistic link between the storage material and disease pathogenesis. However, the accumulation of undegraded substrate(s) can disrupt other lysosomal degradation processes, vesicular traffic, and lysosomal biogenesis to evoke the diverse pathophysiology that is evident in this complex set of disorders.

Increased Alveolar Heparan Sulphate and Reduced Pulmonary Surfactant Amount and Function in the Mucopolysaccharidosis IIIA Mouse.

Mucopolysaccharidosis IIIA (MPS IIIA) is a lysosomal storage disease with significant neurological and skeletal pathologies. Respiratory dysfunction is a secondary pathology contributing to mortality in MPS IIIA patients. Pulmonary surfactant is crucial to optimal lung function and has not been investigated in MPS IIIA. We measured heparan sulphate (HS), lipids and surfactant proteins (SP) in pulmonary tissue and bronchoalveolar lavage fluid (BALF), and surfactant activity in healthy and diseased mice (20 weeks of age). Heparan sulphate, ganglioside GM3 and bis(monoacylglycero)phosphate (BMP) were increased in MPS IIIA lung tissue. There was an increase in HS and a decrease in BMP and cholesteryl esters (CE) in MPS IIIA BALF. Phospholipid composition remained unchanged, but BALF total phospholipids were reduced (49.70%) in MPS IIIA. There was a reduction in SP-A, -C and -D mRNA, SP-D protein in tissue and SP-A, -C and -D protein in BALF of MPS IIIA mice. Captive bubble surfactometry showed an increase in minimum and maximum surface tension and percent surface area compression, as well as a higher compressibility and hysteresis in MPS IIIA surfactant upon dynamic cycling. Collectively these biochemical and biophysical changes in alveolar surfactant are likely to be detrimental to lung function in MPS IIIA.

The very preterm brain in young adulthood: the neural correlates of verbal paired associate learning.

OBJECTIVE: To determine whether preterm birth influences functional neuronal development in adulthood. STUDY DESIGN: We evaluated adults born very preterm (VPT; < 33 weeks of gestation) using a verbal paired-associate learning task within a functional magnetic resonance imaging paradigm. Hippocampi and parahippocampal gyri gray matter volumes were also quantified. RESULTS: Despite similar task performance compared with control participants, VPT adults showed increased brain activation in the left parahippocampal and precentral gyri during Encoding, and in the precentral gyrus during Recall. Very preterm participants also had decreased gray matter volume in the left and right hippocampi yet increased gray matter in the left parahippocampal gyrus. In VPT participants alone, activation in the left parahippocampal gyrus during Encoding (VPT>control participants) was positively associated with gray matter volume in the left parahippocampal gyrus, with VPT participants with the youngest gestational age (eg, born 28 weeks or less) having both increased gray matter and functional activation in this region. These results may reflect the process of neural reorganization after early brain injury. CONCLUSION: Preterm birth leads to functional neuronal differences in adulthood, which are meditated by both structural variations in task-specific regions, and gestational age.

The neural basis of response inhibition and attention allocation as mediated by gestational age.

Children and adolescents born before 33 weeks of gestation, that is very preterm, may experience problems with the inhibitory control of behaviour and the allocation of attention. Previous functional magnetic resonance imaging (fMRI) studies have found preterm-born adolescents to display altered brain activation in tasks measuring inhibitory control. However, adolescence is a period during which dynamic changes are occurring in the brain, and it is not yet known whether these functional alterations will persist into adulthood, or instead reflect developmental delay. This study used an event-related fMRI Go/No-Go motor response inhibition paradigm, which included an oddball task measuring attention allocation to infrequent stimuli, to compare blood-oxygen-level-dependent (BOLD) signal between 26 preterm-born adults and 21 controls. Group differences in brain activation were observed in inhibition and attention networks during both conditions. During motor response inhibition, preterm-born participants compared to controls showed increased BOLD signal in medial and right lateral posterior brain regions, including middle temporal/occipital gyrus, posterior cingulate gyrus and precuneus. During oddball trials, preterm-born young adults displayed attenuated brain activation in a fronto-parietal-cerebellar network which is involved in mediating attention allocation. This pattern of reduced brain activation in task-relevant regions of attention allocation, and increased activation in posterior brain regions during inhibitory control, suggests adult alteration of inhibition and attention processing following very preterm birth, which may reflect a developmental delay.

Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis.

Meiotic crossover frequency varies within genomes, which influences genetic diversity and adaptation. In turn, genetic variation within populations can act to modify crossover frequency in cis and trans. To identify genetic variation that controls meiotic crossover frequency, we screened Arabidopsis accessions using fluorescent recombination reporters. We mapped a genetic modifier of crossover frequency in Col × Bur populations of Arabidopsis to a premature stop codon within TBP-ASSOCIATED FACTOR 4b (TAF4b), which encodes a subunit of the RNA polymerase II general transcription factor TFIID. The Arabidopsis taf4b mutation is a rare variant found in the British Isles, originating in South-West Ireland. Using genetics, genomics, and immunocytology, we demonstrate a genome-wide decrease in taf4b crossovers, with strongest reduction in the sub-telomeric regions. Using RNA sequencing (RNA-seq) from purified meiocytes, we show that TAF4b expression is meiocyte enriched, whereas its paralog TAF4 is broadly expressed. Consistent with the role of TFIID in promoting gene expression, RNA-seq of wild-type and taf4b meiocytes identified widespread transcriptional changes, including in genes that regulate the meiotic cell cycle and recombination. Therefore, TAF4b duplication is associated with acquisition of meiocyte-specific expression and promotion of germline transcription, which act directly or indirectly to elevate crossovers. This identifies a novel mode of meiotic recombination control via a general transcription factor.

Lipid profiles of prostate cancer cells.

Lipids are important cellular components which can be significantly altered in a range of disease states including prostate cancer. Here, a unique systematic approach has been used to define lipid profiles of prostate cancer cell lines, using quantitative mass spectrometry (LC-ESI-MS/MS), FTIR spectroscopy and fluorescent microscopy. All three approaches identified significant difference in the lipid profiles of the three prostate cancer cell lines (DU145, LNCaP and 22RV1) and one non-malignant cell line (PNT1a). Specific lipid classes and species, such as phospholipids (e.g., phosphatidylethanolamine 18:1/16:0 and 18:1/18:1) and cholesteryl esters, detected by LC-ESI-MS/MS, allowed statistical separation of all four prostate cell lines. Lipid mapping by FTIR revealed that variations in these lipid classes could also be detected at a single cell level, however further investigation into this approach would be needed to generate large enough data sets for quantitation. Visualisation by fluorescence microscopy showed striking variations that could be observed in lipid staining patterns between cell lines allowing visual separation of cell lines. In particular, polar lipid staining by a fluorescent marker was observed to increase significantly in prostate cancer lines cells, when compared to PNT1a cells, which was consistent with lipid quantitation by LC-ESI-MS/MS and FTIR spectroscopy. Thus, multiple technologies can be employed to either quantify or visualise changes in lipid composition, and moreover specific lipid profiles could be used to detect and phenotype prostate cancer cells.

N-acetylgalactosamine-6-sulfatase protein detection in MPS IVA patient and unaffected control samples.

BACKGROUND: Mucopolysaccharidosis type IVA (MPS IVA; Morquio syndrome) is a lysosomal storage disorder caused by a deficiency in the activity of the lysosomal hydrolase N-acetylgalactosamine-6-sulfatase (GALNS). MPS IVA patients can present with severe myelopathy, hearing loss, heart valve involvement, short trunk/dwarfism and corneal clouding. Early diagnosis of MPS IVA will allow potential treatments to be implemented before the onset of irreversible pathology. METHODS: We have developed a sensitive immune-quantification assay for the accurate detection of GALNS protein in skin fibroblasts, blood and plasma from unaffected control and MPS IVA patients. RESULTS: MPS IVA patient fibroblast extracts (n=11) had non-detectable (ND)-10 ng/mg of 6-sulfatase protein compared to 3-82 ng/mg for normal controls (n=19). Dried blood-spots from MPS IVA patients (n=4) contained ND-1.3 ng/L of 6-sulfatase protein compared to 18-145 ng/L for normal controls (n=49). Plasma from MPS IVA patients (n=7) contained ND 6-sulfatase protein compared to 1-9 ng/L for normal controls (n=49). CONCLUSIONS: The immune assay described here had the capacity to accurately measure the amount of GALNS protein in various biological samples, providing the basis of an assay that could be further developed to enable newborn and high-risk population screening for MPS IVA patients.

Common antigenicity for two glycosidases.

Enzyme replacement therapy (ERT) has proven to be an effective therapy for some lysosomal storage disorder (LSD) patients. A potential complication during ERT is the generation of an immune response against the replacement protein. We have investigated the antigenicity of two distantly related glycosidases, alpha-glucosidase (Pompe disease or glycogen storage disease type II, GSD II), and alpha-L-iduronidase (Hurler syndrome, mucopolysaccharidosis type I, MPS I). The linear sequence epitope reactivity of affinity purified polyclonal antibodies to recombinant human alpha-glucosidase and alpha-L-iduronidase was defined, to both glycosidases. The polyclonal antibodies exhibited some cross-reactive epitopes on the two proteins. Moreover, a monoclonal antibody to the active site of alpha-glucosidase showed cross-reactivity with a catalytic structural element of alpha-L-iduronidase. In a previous study, in MPS I patients who developed an immune response to ERT, this same site on alpha-L-iduronidase was highly antigenic and the last to tolerise following repeated enzyme infusions. We conclude that glycosidases can exhibit cross-reactive epitopes, and infer that this may relate to common structural elements associated with their active sites.

Endosomal gene expression: a new indicator for prostate cancer patient prognosis?

Prostate cancer continues to be a major cause of morbidity and mortality in men, but a method for accurate prognosis in these patients is yet to be developed. The recent discovery of altered endosomal biogenesis in prostate cancer has identified a fundamental change in the cell biology of this cancer, which holds great promise for the identification of novel biomarkers that can predict disease outcomes. Here we have identified significantly altered expression of endosomal genes in prostate cancer compared to non-malignant tissue in mRNA microarrays and confirmed these findings by qRT-PCR on fresh-frozen tissue. Importantly, we identified endosomal gene expression patterns that were predictive of patient outcomes. Two endosomal tri-gene signatures were identified from a previously published microarray cohort and had a significant capacity to stratify patient outcomes. The expression of APPL1, RAB5A, EEA1, PDCD6IP, NOX4 and SORT1 were altered in malignant patient tissue, when compared to indolent and normal prostate tissue. These findings support the initiation of a case-control study using larger cohorts of prostate tissue, with documented patient outcomes, to determine if different combinations of these new biomarkers can accurately predict disease status and clinical progression in prostate cancer patients.

Aminoglycoside-Induced Premature Stop Codon Read-Through of Mucopolysaccharidosis Type I Patient Q70X and W402X Mutations in Cultured Cells.

The premature stop codon mutations, Q70X and W402X, are the most common α-L-iduronidase gene (IDUA) mutations in mucopolysaccharidosis type I (MPS I) patients. Read-through drugs have been used to suppress premature stop codons, and this can potentially be used to treat patients who have this type of mutation. We examined the effects of aminoglycoside treatment on the IDUA mutations Q70X and W402X in cultured cells and show that 4,5-disubstituted aminoglycosides induced more read-through for the W402X mutation, while 4,6-disubstituted aminoglycosides promoted more read-through for the Q70X mutation: lividomycin (4,5-disubstituted) induced a 7.8-fold increase in α-L-iduronidase enzyme activity for the W402X mutation; NB54 (4,5-disubstituted) induced a 3.7 fold increase in the amount of α-L-iduronidase enzyme activity for the W402X mutation, but had less effect on the Q70X mutation, whereas gentamicin (4,6-disubstituted) had the reverse effect on read-through for both mutations. The predicted mRNA secondary structural changes for both mutations were markedly different, which may explain these different effects on read-through for these two premature stop codons.

Altered endosome biogenesis in prostate cancer has biomarker potential.

UNLABELLED: Prostate cancer is the second most common form of cancer in males, affecting one in eight men by the time they reach the age of 70 years. Current diagnostic tests for prostate cancer have significant problems with both false negatives and false positives, necessitating the search for new molecular markers. A recent investigation of endosomal and lysosomal proteins revealed that the critical process of endosomal biogenesis might be altered in prostate cancer. Here, a panel of endosomal markers was evaluated in prostate cancer and nonmalignant cells and a significant increase in gene and protein expression was found for early, but not late endosomal proteins. There was also a differential distribution of early endosomes, and altered endosomal traffic and signaling of the transferrin receptors (TFRC and TFR2) in prostate cancer cells. These findings support the concept that endosome biogenesis and function are altered in prostate cancer. Microarray analysis of a clinical cohort confirmed the altered endosomal gene expression observed in cultured prostate cancer cells. Furthermore, in prostate cancer patient tissue specimens, the early endosomal marker and adaptor protein APPL1 showed consistently altered basement membrane histology in the vicinity of tumors and concentrated staining within tumor masses. These novel observations on altered early endosome biogenesis provide a new avenue for prostate cancer biomarker investigation and suggest new methods for the early diagnosis and accurate prognosis of prostate cancer. IMPLICATIONS: This discovery of altered endosome biogenesis in prostate cancer may lead to novel biomarkers for more precise cancer detection and patient prognosis.

Empathy and enduring depersonalization: the role of self-related processes.

Empathy has two key components: affective and cognitive. It relies on "embodied" processes such as the generation, representation and perception of feeling states. People diagnosed with Depersonalization Disorder (DPD) report disturbances in affective experience, such as emotional numbing, alongside aberrations in "body image" such as increased self-focus and feelings of "disembodiment". DPD therefore provides a test bed for the role of such self-related processes in empathy. We tested 16 participants diagnosed with DPD and 48 control volunteers on measures of cognitive and affective empathy. We used self-report measures (EQ; Baron-Cohen & Wheelwright, 2004), an objective measure of cognitive empathy-the "Eyes" task (Baron-Cohen, Wheelwright, Hill, Raste, & Plumb, 2001), and a novel task tapping affective empathy, utilizing speech rate as an implicit measure of physiological arousal. We also measured participants' tendency to use mental representations that relate to the self during the affective empathy task. The DPD group showed intact performance on the cognitive empathy task. However, there was a disruption in the physiological component of affective empathy alongside a more pronounced reliance on mental representations of the self. These findings suggest affective empathy to be reliant on intact emotional experience in the observer. In addition, excessive self-focus may be detrimental to an empathic response.