Cellular responses to silencing of PDIA3 (protein disulphide-isomerase A3): Effects on proliferation, migration, and genes in control of active vitamin D

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

Activated EGFR and PDGFR internalize in separate vesicles and downstream AKT and ERK1/2 signaling are differentially impacted by cholesterol depletion

The interplay between membrane subregions and receptor tyrosine kinases (RTK) will influence signaling in both normal and pathological RTK conditions. In this study, epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor β (PDGFR-β) internalizations were investigated by immunofluorescent microscopy following simultaneous treatment with EGF and PDGF-BB. We found that the two receptors utilize separate routes of internalization, which merges in a common perinuclear endosomal compartment after 45 min of stimulation. This is further strengthened when contrasting the recruitment of either EGFR or PDGFR-β to either clathrin or caveolin-1: PDGFR-β dissociates from caveolin-1 upon stimulation, and engages clathrin, whilst an increased recruitment of EGFR, to both clathrin and caveolin-1, was observed upon EGF stimulation. The association between EGFR and caveolin-1 is supported by the observation that EGFR was localized in lipid raft associated fractions, whereas PDGFR-β was not. We also found that disruption of lipid rafts using MβCD led to an increased EGFR dimerization and phosphorylation in response to ligand, as well as a dramatic decrease in AKT- and a smaller but robust decrease in ERK1/2 phosphorylation. This suggest that lipid rafts may be important to effectively connect the EGFR with downstream proteins to facilitate signaling. Our data implies that cholesterol depletion of the plasma membrane affect the signaling of EGFR and PDGFRβ differently.

Metapopulation effective size and conservation genetic goals for the Fennoscandian wolf (Canis lupus) population

The Scandinavian wolf population descends from only five individuals, is isolated, highly inbred and exhibits inbreeding depression. To meet international conservation goals, suggestions include managing subdivided wolf populations over Fennoscandia as a metapopulation; a genetically effective population size of N_e⩾500, in line with the widely accepted long-term genetic viability target, might be attainable with gene flow among subpopulations of Scandinavia, Finland and Russian parts of Fennoscandia. Analytical means for modeling N_e of subdivided populations under such non-idealized situations have been missing, but we recently developed new mathematical methods for exploring inbreeding dynamics and effective population size of complex metapopulations. We apply this theory to the Fennoscandian wolves using empirical estimates of demographic parameters. We suggest that the long-term conservation genetic target for metapopulations should imply that inbreeding rates in the total system and in the separate subpopulations should not exceed Δf=0.001. This implies a meta-Ne of N_eMeta⩾500 and a realized effective size of each subpopulation of N_eRx⩾500. With current local effective population sizes and one migrant per generation, as recommended by management guidelines, the meta-N_e that can be reached is ~250. Unidirectional gene flow from Finland to Scandinavia reduces meta-N_e to ~130. Our results indicate that both local subpopulation effective sizes and migration among subpopulations must increase substantially from current levels to meet the conservation target. Alternatively, immigration from a large (N_e⩾500) population in northwestern Russia could support the Fennoscandian metapopulation, but immigration must be substantial (5–10 effective immigrants per generation) and migration among Fennoscandian subpopulations must nevertheless increase.

Living with faecal incontinence: trying to control the daily life that is out of control

AIMS AND OBJECTIVES

To identify and describe the lived experience of persons living with faecal incontinence and show how it affects daily life.

BACKGROUND

Faecal incontinence is a relatively common condition, with a prevalence ranging from 3-24%, not differing between men and women. There is an under-reporting due to patients' reluctance to talk about their symptoms and consult healthcare professionals about their problems, which means that problems related to faecal incontinence are often underestimated. Living with faecal incontinence affects the quality of life negatively and has a negative impact on family situations, social interaction, etc.

DESIGN

A qualitative interpretative study based on interviews.

METHODS

In-depth interviews were conducted with five informants, all women, living with faecal incontinence. The interviews were transcribed verbatim and analysed using interpretive phenomenological analysis.

RESULTS

The analysis identified four themes: self-affirmation, guilt and shame, limitations in life and personal approach. The themes differ from each other, but are related and have similarities. The results show different aspects of living with faecal incontinence and how they affected daily life.

CONCLUSIONS

Living with faecal incontinence is a complex problem affecting everyday life in a number of different ways. It is a highly distressing and socially incapacitating problem. Living with faecal incontinence is about trying to control the daily life which is out of control. Living with faecal incontinence cannot be generalised as individuals experience the situation in unique ways.

RELEVANCE TO CLINICAL PRACTICE

By gaining insight into the experience of living with faecal incontinence, healthcare professionals can deepen their understanding of this complex problem and thereby better address it and provide more individually based care.

Early vertebrate chromosome duplications and the evolution of the neuropeptide Y receptor gene regions

Background

One of the many gene families that expanded in early vertebrate evolution is the neuropeptide (NPY) receptor family of G-protein coupled receptors. Earlier work by our lab suggested that several of the NPY receptor genes found in extant vertebrates resulted from two genome duplications before the origin of jawed vertebrates (gnathostomes) and one additional genome duplication in the actinopterygian lineage, based on their location on chromosomes sharing several gene families. In this study we have investigated, in five vertebrate genomes, 45 gene families with members close to the NPY receptor genes in the compact genomes of the teleost fishes Tetraodon nigroviridis and Takifugu rubripes. These correspond to Homo sapiens chromosomes 4, 5, 8 and 10.

Results

Chromosome regions with conserved synteny were identified and confirmed by phylogenetic analyses in H. sapiens, M. musculus, D. rerio, T. rubripes and T. nigroviridis. 26 gene families, including the NPY receptor genes, (plus 3 described recently by other labs) showed a tree topology consistent with duplications in early vertebrate evolution and in the actinopterygian lineage, thereby supporting expansion through block duplications. Eight gene families had complications that precluded analysis (such as short sequence length or variable number of repeated domains) and another eight families did not support block duplications (because the paralogs in these families seem to have originated in another time window than the proposed genome duplication events). RT-PCR carried out with several tissues in T. rubripes revealed that all five NPY receptors were expressed in the brain and subtypes Y2, Y4 and Y8 were also expressed in peripheral organs.

Conclusion

We conclude that the phylogenetic analyses and chromosomal locations of these gene families support duplications of large blocks of genes or even entire chromosomes. Thus, these results are consistent with two early vertebrate tetraploidizations forming a paralogon comprising human chromosomes 4, 5, 8 and 10 and one teleost tetraploidization. The combination of positional and phylogenetic data further strengthens the identification of orthologs and paralogs in the NPY receptor family.

Pufferfish and zebrafish have five distinct NPY receptor subtypes, but have lost appetite receptors Y1 and Y5

The two neuropeptide Y (NPY) receptors Y1 and Y5 stimulate feeding in mammals, but are missing in the euteleosts, zebrafish and pufferfish (Takifugu rubripes). Both species have five other subtypes called Y2, Y7, Ya, Yb, and Yc. RT-PCR studies in pufferfish show that all five are expressed in the brain and may mediate NPY effects on feeding. Y2, Ya, and Yb are also broadly expressed in peripheral organs. These results reveal interesting differences in the NPY system of teleosts and mammals that may have arisen in the genetic turmoil involving the basal ray-fin fish tetraploidization.