Potential sources, impact and mitigation of stress in the workplace : a review and preliminary case of AD-CJO Technology Company

The objective of this paper was to investigate the causes of stress in an organisation, and its effects on individuals in the organisations, in order to propose mechanisms of mitigating stress in the workplace. Data was obtained through literatures that were reviewed as well as through a stress questionnaire, from the International Stress Management Association (ISMA), which was handed out to the procurement department of AD-CJO Technology Company. An interview that was conducted with a senior Manager in the Procurement department of the company. The findings reveals that stress is a major issue in the workplace, hence, organisations should strive to combat it to a manageable degree, so that employees are not adversely affected. Some ameliorating mechanisms such as employee wellness programmes, stress management programs, counselling, and social support systems have been proposed to address the problems of stress at AD-CJO Technology Company and any organisation. However, it should kept in mind that stress cannot be eradicated to a zero base. Some element of it is required in order to stay motivated and develop a drive towards personal and organisational goal attainment

Effects of age and Pax6 deficiency on mouse limbal stem cell function

The conventional view for corneal epithelial maintenance suggests that a stem cell population found in the limbus (at the rim of the cornea) produces daughter cells, called transient amplifying cells, which migrate centripetally. This limbal stem cell (LSC) hypothesis was recently questioned and the alternative model suggests that stem cells are present throughout the corneal epithelium. The main aims of this thesis were to investigate whether age and Pax6 genotype affect LSC function. Previous work with X-inactivation mosaics revealed radial stripes of β-galactosidase-expressing cells in the corneal epithelium (from about 5 weeks of age), which decreased with age and were reduced in Pax6+/- mice (a model for aniridia, a human eye disease). The reduction in Pax6+/- mice could be due to either reduced LSCs function or a more coarse-grained mosaicism caused by reduced cell mixing during development. Comparison of patch sizes in Pax6+/- and wild-type X-inactivation mosaics showed that patches were smaller in Pax6+/- cornea epithelia before the initiation of stripes (3 weeks of age). This implies that stripe-number reduction is not caused by reduced cell mixing, so an effect on LSC function remained a possibility. Thus, the numbers of label-retaining cells (putative stem cells) in Pax6+/- were compared to controls at 15 and 30 weeks old but they were not reduced at 30 weeks or in Pax6+/- mice, as had been predicted. The failure to demonstrate the predicted result suggests either that the hypothesis was incorrect or the experimental approach was inappropriate. Furthermore, it was discovered that mice expressing β-galactosidase under the keratin 5 promoter produced rare stripes in the corneal epithelium, which are likely to represent clonal lineages derived from individual stem cells. Older mice demonstrated a significantly lower frequency of stripes, a result compatible with the predicted reduction of active LSC with age. Pax6+/- corneas were highly abnormal and stripes were not formed properly, so direct comparison was not possible. Finally, pilot experiments with conditional expression of a reporter gene revealed the successful formation of a stripe, and hence provide a plausible alternative approach to compare stripe numbers reflecting active LSCs but the method has yet to be optimised. Overall, the results suggest that LSCs are reduced with age and support the limbal location of stem cells maintaining the corneal epithelium

Directed Differentiation of Human Pluripotent Stem Cells to Microglia

Microglia, the immune cells of the brain, are crucial to proper development and maintenance of the CNS, and their involvement in numerous neurological disorders is increasingly being recognized. To improve our understanding of human microglial biology, we devised a chemically defined protocol to generate human microglia from pluripotent stem cells. Myeloid progenitors expressing CD14/CX3CR1 were generated within 30 days of differentiation from both embryonic and induced pluripotent stem cells (iPSCs). Further differentiation of the progenitors resulted in ramified microglia with highly motile processes, expressing typical microglial markers. Analyses of gene expression and cytokine release showed close similarities between iPSC-derived (iPSC-MG) and human primary microglia as well as clear distinctions from macrophages. iPSC-MG were able to phagocytose and responded to ADP by producing intracellular Ca 2+ transients, whereas macrophages lacked such response. The differentiation protocol was highly reproducible across several pluripotent stem cell lines

The Sixth Annual Translational Stem Cell Research Conference of the New York Stem Cell Foundation

The New York Stem Cell Foundation's "Sixth Annual Translational Stem Cell Research Conference" convened on October 11-12, 2011 at the Rockefeller University in New York City. Over 450 scientists, patient advocates, and stem cell research supporters from 14 countries registered for the conference. In addition to poster and platform presentations, the conference featured panels entitled "Road to the Clinic" and "The Future of Regenerative Medicine". © 2012 New York Academy of Sciences

Lineage tracing in the adult mouse corneal epithelium supports the limbal epithelial stem cell hypothesis with intermittent periods of stem cell quiescence

We thank Drs Kevin Painter (Heriot-Watt University), Steven Morley and Richard Mort for their helpful discussion. We also thank Mr Ronnie Grant for his help with the figures, staff at BRR, University of Edinburgh, for their specialised technical services and Drs Bettina Wilm (Liverpool University), Peter Hohenstein, Richard Mort and Alison Mackinnon for kindly providing founder mice. This work was supported by the UK Biotechnology and Biological Sciences Research Council (grants BB/J015172/1 and BB/J015237/1).Peer reviewedPublisher PD

Normal X-inactivation mosaicism in corneas of heterozygous FlnaDilp2/+ female mice--a model of human Filamin A (FLNA) diseases

<p>Abstract</p> <p>Background</p> <p>Some abnormalities of mouse corneal epithelial maintenance can be identified by the atypical mosaic patterns they produce in X-chromosome inactivation mosaics and chimeras. Human <it>FLNA</it>/+ females, heterozygous for X-linked, filamin A gene (<it>FLNA</it>) mutations, display a range of disorders and X-inactivation mosaicism is sometimes quantitatively unbalanced. <it>Flna</it>^{<it>Dilp2/+ </it>}mice, heterozygous for an X-linked filamin A (<it>Flna</it>) nonsense mutation have variable eye, skeletal and other abnormalities, but X-inactivation mosaicism has not been investigated. The aim of this study was to determine whether X-inactivation mosaicism in the corneal epithelia of <it>Flna</it>^{<it>Dilp2/+ </it>}mice was affected in any way that might predict abnormal corneal epithelial maintenance.</p> <p>Results</p> <p>X-chromosome inactivation mosaicism was studied in the corneal epithelium and a control tissue (liver) of <it>Flna</it>^{<it>Dilp2/+ </it>}and wild-type (WT) female X-inactivation mosaics, hemizygous for the X-linked, <it>LacZ </it>reporter H253 transgene, using β-galactosidase histochemical staining. The corneal epithelia of <it>Flna</it>^{<it>Dilp2/+ </it>}and WT X-inactivation mosaics showed similar radial, striped patterns, implying epithelial cell movement was not disrupted in <it>Flna</it>^{<it>Dilp2/+ </it>}corneas. Corrected stripe numbers declined with age overall (but not significantly for either genotype individually), consistent with previous reports suggesting an age-related reduction in stem cell function. Corrected stripe numbers were not reduced in <it>Flna</it>^{<it>Dilp2/+ </it>}compared with WT X-inactivation mosaics and mosaicism was not significantly more unbalanced in the corneal epithelia or livers of <it>Flna</it>^{<it>Dilp2/+ </it>}than wild-type <it>Flna^+/+</it>X-inactivation mosaics.</p> <p>Conclusions</p> <p>Mosaic analysis identified no major effect of the mouse <it>Flna^Dilp2</it>mutation on corneal epithelial maintenance or the balance of X-inactivation mosaicism in the corneal epithelium or liver.</p

Abnormal corneal epithelial maintenance in mice heterozygous for the micropinna microphthalmia mutation Mp

We investigated the corneal morphology of adult Mp/+ mice, which are heterozygous for the micropinna microphthalmia mutation, and identified several abnormalities, which implied that corneal epithelial maintenance was abnormal. The Mp/+ corneal epithelium was thin, loosely packed and contained goblet cells in older mice. Evidence also suggested that the barrier function was compromised. However, there was no major effect on corneal epithelial cell turnover and mosaic patterns of radial stripes indicated that radial cell movement was normal. Limbal blood vessels formed an abnormally wide limbal vasculature ring, K19-positive cells were distributed more widely than normal and K12 was weakly expressed in the peripheral cornea. This raises the possibilities that the limbal-corneal boundary was poorly defined or the limbus was wider than normal. BrdU label-retaining cell numbers and quantitative clonal analysis suggested that limbal epithelial stem cell numbers were not depleted and might be higher than normal. However, as corneal epithelial homeostasis was abnormal, it is possible that Mp/+ stem cell function was impaired. It has been shown recently that the Mp mutation involves a chromosome 18 inversion that disrupts the Fbn2 and Isoc1 genes and produces an abnormal, truncated fibrillin-2(MP) protein. This abnormal protein accumulates in the endoplasmic reticulum (ER) of cells that normally express Fbn2 and causes ER stress. It was also shown that Fbn2 is expressed in the corneal stroma but not the corneal epithelium, suggesting that the presence of truncated fibrillin-2(MP) protein in the corneal stroma disrupts corneal epithelial homeostasis in Mp/+ mice

Analysis of compound heterozygotes reveals that the mouse floxed Pax6 tm1Ued allele produces abnormal eye phenotypes

Analysis of abnormal phenotypes produced by different types of mutations has been crucial for our understanding of gene function. Some floxed alleles that retain a neomycin-resistance selection cassette (neo cassette) are not equivalent to wild-type alleles and provide useful experimental resources. Pax6 is an important developmental gene and the aim of this study was to determine whether the floxed Pax6(tm1Ued) (Pax6(fl)) allele, which has a retained neo cassette, produced any abnormal eye phenotypes that would imply that it differs from the wild-type allele. Homozygous Pax6(fl/fl) and heterozygous Pax6(fl/+) mice had no overt qualitative eye abnormalities but morphometric analysis showed that Pax6(fl/fl) corneas tended be thicker and smaller in diameter. To aid identification of weak effects, we produced compound heterozygotes with the Pax6(Sey-Neu) (Pax6(−)) null allele. Pax6(fl/−) compound heterozygotes had more severe eye abnormalities than Pax6(+/−) heterozygotes, implying that Pax6(fl) differs from the wild-type Pax6(+) allele. Immunohistochemistry showed that the Pax6(fl/−) corneal epithelium was positive for keratin 19 and negative for keratin 12, indicating that it was abnormally differentiated. This Pax6(fl) allele provides a useful addition to the existing Pax6 allelic series and this study demonstrates the utility of using compound heterozygotes with null alleles to unmask cryptic effects of floxed alleles. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11248-016-9962-4) contains supplementary material, which is available to authorized users

Cellular senescence in progenitor cells contributes to diminished remyelination potential in progressive multiple sclerosis

Cellular senescence is a form of adaptive cellular physiology associated with aging. Cellular senescence causes a proinflammatory cellular phenotype that impairs tissue regeneration, has been linked to stress, and is implicated in several human neurodegenerative diseases. We had previously determined that neural progenitor cells (NPCs) derived from induced pluripotent stem cell (iPSC) lines from patients with primary progressive multiple sclerosis (PPMS) failed to promote oligodendrocyte progenitor cell (OPC) maturation, whereas NPCs from age-matched control cell lines did so efficiently. Herein, we report that expression of hallmarks of cellular senescence were identified in SOX2+ progenitor cells within white matter lesions of human progressive MS (PMS) autopsy brain tissues and iPS-derived NPCs from patients with PPMS. Expression of cellular senescence genes in PPMS NPCs was found to be reversible by treatment with rapamycin, which then enhanced PPMS NPC support for oligodendrocyte (OL) differentiation. A proteomic analysis of the PPMS NPC secretome identified high-mobility group box-1 (HMGB1), which was found to be a senescence-associated inhibitor of OL differentiation. Transcriptome analysis of OPCs revealed that senescent NPCs induced expression of epigenetic regulators mediated by extracellular HMGB1. Lastly, we determined that progenitor cells are a source of elevated HMGB1 in human white matter lesions. Based on these data, we conclude that cellular senescence contributes to altered progenitor cell functions in demyelinated lesions in MS. Moreover, these data implicate cellular aging and senescence as a process that contributes to remyelination failure in PMS, which may impact how this disease is modeled and inform development of future myelin regeneration strategies