Gamma-rays from millisecond pulsars in Globular Clusters

Globular clusters (GCs) with their ages of the order of several billion years contain many final products of evolution of stars such as: neutron stars, white dwarfs and probably also black holes. These compact objects can be at present responsible for the acceleration of particles to relativistic energies. Therefore, gamma-ray emission is expected from GCs as a result of radiation processes occurring either in the inner magnetosperes of millisecond pulsars or in the vicinity of accreting neutron stars and white dwarfs or as a result of interaction of particles leaving the compact objects with the strong radiation field within the GC. Recently, GeV gamma-ray emission has been detected from several GCs by the new satellite observatory Fermi. Also Cherenkov telescopes reported interesting upper limits at the TeV energies which start to constrain the content of GCs. We review the results of these gamma-ray observations in the context of recent scenarios for their origin.Comment: 20 pages, 9 figures, will be published in Astrophysics and Space Science Series (Springer), eds. N. Rea and D.F. Torre

A multi-exon deletion within WWOX is associated with a 46,XY disorder of sex development

Disorders of sex development (DSD) are congenital conditions where chromosomal, gonad or genital development is atypical. In a significant proportion of 46,XY DSD cases it is not possible to identify a causative mutation, making genetic counseling difficult and potentially hindering optimal treatment. Here, we describe the analysis of a 46,XY DSD patient that presented at birth with ambiguous genitalia. Histological analysis of the surgically removed gonads showed bilateral undifferentiated gonadal tissue and immature testis, both containing malignant germ cells. We screened genomic DNA from this patient for deletions and duplications using an Illumina whole-genome SNP microarray. This analysis revealed a heterozygous deletion within the WWOX gene on chromosome 16, removing exons 6-8. Analysis of parental DNA showed that the deletion was inherited from the mother. cDNA analysis confirmed that the deletion maintained the reading frame, with exon 5 being spliced directly onto exon 9. This deletion is the first description of a germline rearrangement affecting the coding sequence of WWOX in humans. Previously described Wwox knockout mouse models showed gonadal abnormalities, supporting a role for WWOX in human gonad development

WWOX expression in colorectal cancer—a real-time quantitative RT-PCR study

The WWOX gene is a tumour suppressor gene affected in various types of malignancies. Numerous studies showed either loss or reduction of the WWOX expression in variety of tumours, including breast, ovary, liver, stomach and pancreas. Recent study demonstrated that breast cancer patients exhibiting higher WWOX expression showed significantly longer disease-free survival in contrast to the group with lower relative WWOX level. This work was undertaken to show whether similar phenomena take place in colon tumours and cell lines. To assess the correlation of WWOX gene expression with prognosis and cancer recurrence in 99 colorectal cancer patients, we performed qRT-PCR analysis. We also performed analysis of WWOX promoter methylation status using MethylScreen method and analysis of loss of heterozygosity (LOH) status at two WWOX-related loci, previously shown to be frequently deleted in various types of tumours. A significantly better disease-free survival was observed among patients with tumours exhibiting high level of WWOX (hazard ratio = 0.39; p = 0.0452; Mantel–Cox log-rank test), but in multivariate analysis it was not an independent prognostic factor. We also found that although in colorectal cancer WWOX expression varies among patients and correlates with DFS, the exact mode of decrease in this type of tumour was not found. We failed to find the evidence of LOH in WWOX region, or hypermethylation in promoter regions of this gene. Although we provide the evidence for tumour-suppressive role of WWOX gene expression in colon, we were unable to identify the molecular mechanism responsible for this

Generation and Characterization of Mice Carrying a Conditional Allele of the Wwox Tumor Suppressor Gene

WWOX, the gene that spans the second most common human chromosomal fragile site, FRA16D, is inactivated in multiple human cancers and behaves as a suppressor of tumor growth. Since we are interested in understanding WWOX function in both normal and cancer tissues we generated mice harboring a conditional Wwox allele by flanking Exon 1 of the Wwox gene with LoxP sites. Wwox knockout (KO) mice were developed by breeding with transgenic mice carrying the Cre-recombinase gene under the control of the adenovirus EIIA promoter. We found that Wwox KO mice suffered from severe metabolic defect(s) resulting in growth retardation and all mice died by 3 wk of age. All Wwox KO mice displayed significant hypocapnia suggesting a state of metabolic acidosis. This finding and the known high expression of Wwox in kidney tubules suggest a role for Wwox in acid/base balance. Importantly, Wwox KO mice displayed histopathological and hematological signs of impaired hematopoeisis, leukopenia, and splenic atrophy. Impaired hematopoeisis can also be a contributing factor to metabolic acidosis and death. Hypoglycemia and hypocalcemia was also observed affecting the KO mice. In addition, bone metabolic defects were evident in Wwox KO mice. Bones were smaller and thinner having reduced bone volume as a consequence of a defect in mineralization. No evidence of spontaneous neoplasia was observed in Wwox KO mice. We have generated a new mouse model to inactivate the Wwox tumor suppressor gene conditionally. This will greatly facilitate the functional analysis of Wwox in adult mice and will allow investigating neoplastic transformation in specific target tissues

Loss of Wwox Perturbs Neuronal Migration and Impairs Early Cortical Development

Mutations in the WWOX gene cause a broad range of ultra-rare neurodevelopmental and brain degenerative disorders, associated with a high likelihood of premature death in animal models as well as in humans. The encoded Wwox protein is a WW domain-containing oxidoreductase that participates in crucial biological processes including tumor suppression, cell growth/differentiation and regulation of steroid metabolism, while its role in neural development is less understood. We analyzed the exomes of a family affected with multiple pre- and postnatal anomalies, including cerebellar vermis hypoplasia, severe neurodevelopmental impairment and refractory epilepsy, and identified a segregating homozygous WWOX mutation leading to a premature stop codon. Abnormal cerebral cortex development due to a defective architecture of granular and molecular cell layers was found in the developing brain of a WWOX-deficient human fetus from this family. A similar disorganization of cortical layers was identified in lde/lde rats (carrying a homozygous truncating mutation which disrupts the active Wwox C-terminal domain) investigated at perinatal stages. Transcriptomic analyses of Wwox-depleted human neural progenitor cells showed an impaired expression of a number of neuronal migration-related genes encoding for tubulins, kinesins and associated proteins. These findings indicate that loss of Wwox may affect different cytoskeleton components and alter prenatal cortical development, highlighting a regulatory role of the WWOX gene in migrating neurons across different species

Conditional Wwox Deletion in Mouse Mammary Gland by Means of Two Cre Recombinase Approaches

Loss of WWOX expression has been reported in many different cancers including breast cancer. Elucidating the function of this gene in adult tissues has not been possible with full Wwox knockout models. Here we characterize the first conditional models of Wwox ablation in mouse mammary epithelium utilizing two transgenic lines expressing Cre recombinase, keratin 5-Cre (BK5-Cre) and MMTV-Cre. In the BK5-Cre model we observed very efficient Wwox ablation in KO mammary glands. However, BK5-Cre Wwox KO animals die prematurely for unknown reasons. In the MMTV-Cre model we observed significant ablation of Wwox in mammary epithelium with no effect on survival. In both of these models we found that Wwox deletion resulted in impaired mammary branching morphogenesis. We demonstrate that loss of Wwox is not carcinogenic in our KO models. Furthermore, no evidence of increase proliferation or development of premalignant lesions was observed. In none of the models did loss of a single Wwox allele (i.e. haploinsufficiency) have any observable phenotypic effect in mammary gland. To better understand the function of Wwox in the mammary gland, transcriptome profiling was performed. We observed that Wwox ablation results in the deregulation of genes involved in various cellular processes. We found that expression of the non-canonical Wnt ligand, Wnt5a, was significantly upregulated in Wwox KO mammary epithelium. Interestingly, we also determined that components of the Jak/Stat3 signaling pathway were upregulated in KO mice and this correlated with a very robust increase in phospho-Stat3 signaling, which warrants further testing. Even though the loss of Wwox expression in breast and other cancers is very well documented, our findings suggest that Wwox does not act as a classical tumor suppressor as previously thought

WWOX protein expression varies among ovarian carcinoma histotypes and correlates with less favorable outcome

BACKGROUND: The putative tumor suppressor WWOX gene spans the common chromosomal fragile site 16D (FRA16D) at chromosome area 16q23.3-24.1. This region is a frequent target for loss of heterozygosity and chromosomal rearrangement in ovarian, breast, hepatocellular, prostate carcinomas and other neoplasias. The goal of these studies was to evaluate WWOX protein expression levels in ovarian carcinomas to determine if they correlated with clinico-pathological parameters, thus providing additional support for WWOX functioning as a tumor suppressor. METHODS: We performed WWOX protein expression analyses by means of immunobloting and immunohistochemistry on normal ovaries and specific human ovarian carcinoma Tissue Microarrays (n = 444). Univariate analysis of clinical-pathological parameters based on WWOX staining was determined by χ(2 )test with Yates' correction. The basic significance level was fixed at p < 0.05. RESULTS: Immunoblotting analysis from normal ovarian samples demonstrated consistently strong WWOX expression while 37% ovarian carcinomas showed reduced or undetectable WWOX protein expression levels. The immunohistochemistry of normal human ovarian tissue sections confirmed strong WWOX expression in ovarian surface epithelial cells and in epithelial inclusion cysts within the cortex. Out of 444 ovarian carcinoma samples analyzed 30% of tumors showed lack of or barely detectable WWOX expression. The remaining ovarian carcinomas (70%) stained moderately to strongly positive for this protein. The two histotypes showing significant loss of WWOX expression were of the Mucinous (70%) and Clear Cell (42%) types. Reduced WWOX expression demonstrated a significant association with clinical Stage IV (FIGO) (p = 0.007), negative Progesterone Receptor (PR) status (p = 0.008) and shorter overall survival (p = 0.03). CONCLUSION: These data indicate that WWOX protein expression is highly variable among ovarian carcinoma histotypes. It was also observed that subsets of ovarian tumors demonstrated loss of WWOX expression and is potentially associated with patient outcome

Central neuropeptide Y receptors are involved in 3(rd )ventricular ghrelin induced alteration of colonic transit time in conscious fed rats

BACKGROUND: Feeding related peptides have been shown to be additionally involved in the central autonomic control of gastrointestinal functions. Recent studies have shown that ghrelin, a stomach-derived orexigenic peptide, is involved in the autonomic regulation of GI function besides feeding behavior. Pharmacological evidence indicates that ghrelin effects on food intake are mediated by neuropeptide Y in the central nervous system. METHODS: In the present study we examine the role of ghrelin in the central autonomic control of GI motility using intracerobroventricular and IP microinjections in a freely moving conscious rat model. Further the hypothesis that a functional relationship between NPY and ghrelin within the CNS exists was addressed. RESULTS: ICV injections of ghrelin (0.03 nmol, 0.3 nmol and 3.0 nmol/5 μl and saline controls) decreased the colonic transit time up to 43%. IP injections of ghrelin (0.3 nmol – 3.0 nmol kg(-1 )BW and saline controls) decreased colonic transit time dose related. Central administration of the NPY(1 )receptor antagonist, BIBP-3226, prior to centrally or peripherally administration of ghrelin antagonized the ghrelin induced stimulation of colonic transit. On the contrary ICV-pretreatment with the NPY(2 )receptor antagonist, BIIE-0246, failed to modulate the ghrelin induced stimulation of colonic motility. CONCLUSION: The results suggest that ghrelin acts in the central nervous system to modulate gastrointestinal motor function utilizing NPY(1 )receptor dependent mechanisms