Differential Role of gp130-Dependent STAT and Ras Signalling for Haematopoiesis Following Bone-Marrow Transplantation

INTRODUCTION: Bone marrow transplantation (BMT) is a complex process regulated by different cytokines and growth factors. The pleiotropic cytokine IL-6 (Interleukin-6) and related cytokines of the same family acting on the common signal transducer gp130 are known to play a key role in bone marrow (BM) engraftment. In contrast, the exact signalling events that control IL-6/gp130-driven haematopoietic stem cell development during BMT remain unresolved. METHODS: Conditional gp130 knockout and knockin mice were used to delete gp130 expression (gp130(ΔMx)), or to selectively disrupt gp130-dependent Ras (gp130(ΔMxRas)) or STAT signalling (gp130(ΔMxSTAT)) in BM cells. BM derived from the respective strains was transplanted into irradiated wildtype hosts and repopulation of various haematopoietic lineages was monitored by flow cytometry. RESULTS: BM derived from gp130 deficient donor mice (gp130(ΔMx)) displayed a delayed engraftment, as evidenced by reduced total white blood cells (WBC), marked thrombocytopenia and anaemia in the early phase after BMT. Lineage analysis unravelled a restricted development of CD4(+) and CD8(+) T-cells, CD19(+) B-cells and CD11b(+) myeloid cells after transplantation of gp130-deficient BM grafts. To further delineate the two major gp130-induced signalling cascades, Ras-MAPK and STAT1/3-signalling respectively, we used gp130(ΔMxRas) and gp130(ΔMxSTAT) donor BM. BMT of gp130(ΔMxSTAT) cells significantly impaired engraftment of CD4(+), CD8(+), CD19(+) and CD11b(+) cells, whereas gp130(ΔMxRas) BM displayed a selective impairment in early thrombopoiesis. Importantly, gp130-STAT1/3 signalling deficiency in BM grafts severely impaired survival of transplanted mice, thus demonstrating a pivotal role for this pathway in BM graft survival and function. CONCLUSION: Our data unravel a vital function of IL-6/gp130-STAT1/3 signals for BM engraftment and haematopoiesis, as well as for host survival after transplantation. STAT1/3 and ras-dependent pathways thereby exert distinct functions on individual bone-marrow-lineages

"Me's me and you's you": Exploring patients' perspectives of single patient (n-of-1) trials in the UK

BACKGROUND: The n-of-1 trial offers a more methodologically sound approach to determining optimum treatment for an individual patient than "trials of therapy" routinely conducted in clinical practice. However, such methodology is rarely used in the UK. This pilot study explores the acceptability of n-of-1 trials to patients in the UK. METHODS: Patients with osteoarthritis of the knee were recruited to their own 12-week n-of-1 trial comparing either two knee supports or an NSAID with simple analgesic. Patients were interviewed at the start and completion of their trial to explore reasons for participation, understanding of the trial design and experiences of participation. Daily diaries were completed to inform future treatment. RESULTS: Nine patients participated (5 supports, 4 drugs). Patients were keen to participate, believing that the trial may lead to personal gains such as improved symptom control and quality of life. However, recruitment to the pharmacological comparison was more difficult since this could also entail risk. All patients were eager to complete the trial, even when difficulties were encountered. Completing the daily diary provided some patients with greater insight into their condition, which allowed them to improve their self-management. The n-of-1 trial design was viewed as a 'logical' design offering an efficient method of reaching a personalised treatment decision tailored to suit individual needs and preferences. CONCLUSION: This pilot study suggests that patients perceive the n-of-1 trial as an acceptable approach to the individualisation of treatment. In addition, further benefits over and above any gained from the interventions can be derived from involvement in such a study

Hepatic acute-phase proteins control innate immune responses during infection by promoting myeloid-derived suppressor cell function

Acute-phase proteins (APPs) are an evolutionarily conserved family of proteins produced mainly in the liver in response to infection and inflammation. Despite vast pro- and antiinflammatory properties ascribed to individual APPs, their collective function during infections remains poorly defined. Using a mouse model of polymicrobial sepsis, we show that abrogation of APP production by hepatocyte-specific gp130 deletion, the signaling receptor shared by IL-6 family cytokines, strongly increased mortality despite normal bacterial clearance. Hepatic gp130 signaling through STAT3 was required to control systemic inflammation. Notably, hepatic gp130–STAT3 activation was also essential for mobilization and tissue accumulation of myeloid-derived suppressor cells (MDSCs), a cell population mainly known for antiinflammatory properties in cancer. MDSCs were critical to regulate innate inflammation, and their adoptive transfer efficiently protected gp130-deficient mice from sepsis-associated mortality. The hepatic APPs serum amyloid A and Cxcl1/KC cooperatively promoted MDSC mobilization, accumulation, and survival, and reversed dysregulated inflammation and restored survival of gp130-deficient mice. Thus, gp130-dependent communication between the liver and MDSCs through APPs controls inflammatory responses during infection

Applicant perspectives during selection

We provide a comprehensive but critical review of research on applicant reactions to selection procedures published since 2000 (n = 145), when the last major review article on applicant reactions appeared in the Journal of Management. We start by addressing the main criticisms levied against the field to determine whether applicant reactions matter to individuals and employers (“So what?”). This is followed by a consideration of “What’s new?” by conducting a comprehensive and detailed review of applicant reaction research centered upon four areas of growth: expansion of the theoretical lens, incorporation of new technology in the selection arena, internationalization of applicant reactions research, and emerging boundary conditions. Our final section focuses on “Where to next?” and offers an updated and integrated conceptual model of applicant reactions, four key challenges, and eight specific future research questions. Our conclusion is that the field demonstrates stronger research designs, with studies incorporating greater control, broader constructs, and multiple time points. There is also solid evidence that applicant reactions have significant and meaningful effects on attitudes, intentions, and behaviors. At the same time, we identify some remaining gaps in the literature and a number of critical questions that remain to be explored, particularly in light of technological and societal changes

AN EXPLORATION OF THE USE OF STUDENT SERVICES AND SUPPORT PROGRAMS IN AN ATHLETIC DEPARMENT

The purpose of the study was to explore the utilization of student services and support programs by athletic personnel. The sample was comprised of eight academic advisors (4 males and 4 females) from eight athletic institutions who agreed to participate in oral interviews. The institutions represented medium and large public universities. The participants expressed their perceptions of student services and support programs to the contributions and educational outcomes for student-athletes. The data analysis portion of the study produced two themes: (1) support services and programs in an athletic department; and (2) collaboration within the institution. The results helped athletic personnel to gain knowledge and experience of the importance in providing student support and services in athletic departments

The winged helix transcription factor Foxl1 in proliferation and homeostasis of the gastrointestinal tract and liver

Tissue homeostasis is a tightly controlled and regulated process that varies greatly between the multiple organs contained in an organism. For instance, the endodermally derived gastrointestinal epithelium and liver have very different proliferation profiles. Foxl1 (forkhead box l1) encodes a winged-helix transcription factor with constituative expression in the mesenchyme of the gastrointestinal tract and described here, induced expression expression in the liver following injury. To investigate the role of Foxl1 in the gastrointestinal tract a knockout mouse model was generated by Kaestner et al. in 1997. Foxl1 null mice are born at decreased Mendelian ratios and, although having similar birth weights to their WT and heterozygous littermates, are significantly growth retarded postnatally. Furthermore, the gastrointestinal tracts of Foxl1 null embryos display a developmental delay. The adults have increased proliferation, loss of tissue architecture and an increase in nuclear levels of β-catenin. Constitutive activation of the Wnt/APC/β-catenin pathway is a frequent initiating event in gastrointestinal carcinogenesis. Mutations in the Adenomatous Polyposis Coli (APC) gene upregulate Wnt signaling by stabilizing β-catenin and thereby cause activation of targets important in proliferation control. In collaboration with Dr. Nathalie Perreault, I have shown that loss of the mesenchymal transcription factor Foxl1 leads to a marked increase in tumor multiplicity in the colon of ApcMin mice. Apc+/Min; Foxl1-/- mice also develop gastric tumors not observed in ApcMin mice. My work revealed that these effects are caused by earlier tumor initiation due to accelerated loss of heterozygosity (LOH) at the Apc locus. This distinguishes Foxl1 as the first mesenchymal Modifier of Min and demonstrates that it plays a key role in gastrointestinal tumorigenesis through cell-to-cell signaling. The Cre-loxP technology is a powerful tool for the analysis of gene function in the gastrointestinal tract, however, no Cre-expressing transgenic mouse lines ( Cre lines ) exist for the deletion of loxP-flanked genes specifically in gut mesoderm. To address this deficiency. I have derived a bacterial artificial chromosome (BAC) based transgenic mouse line in which the Cre gene is controlled by the Foxl1 promoter and enhancer elements. X-Gal staining of Foxl1-Cre;Rosa26R bi-transgenic lines confirm that Foxl1-Cre results in recombination specifically in the gastrointestinal mesenchyme. The Foxl1-Cre line will facilitate the dissection of mesenchymal to epithelial signaling that is known to play a major role in the patterning and function of the gastrointestinal tract. In addition, it will facilitate the identification the cell type(s) expressing Foxl1 in other organs. Cell signaling pathways are implicated in causing and affecting the outcome of many diseases. In the liver, fibrosis is a major cause of liver disease for which the only present cure is transplantation. Growth signals emanating from mesenchymal cells, such as the hepatic stellate cell, other non-parenchymal cells and hepatocytes have been shown to be causative of fibrosis and liver damage. There are several forkhead transcription factors expressed in the developing and adult liver, such as the Foxa genes. Preliminary data from activated hepatic stellate cells encouraged further investigation into a potential role for Foxl1 in the liver. We hypothesized that Foxl1 may play a role in livers ability to respond to damage or injury. To investigate this possibility we employed the bile duct ligation model of cholestatic liver injury to address the role of Foxl1. I showed using laser capture microdissection that the Foxl1 gene is massively activated in the portal tract, but not parenchyma, of the liver. In the absence of Foxl1 there is increased persistence of necrosis and changes in cholangiocytes and hepatocyte proliferation and following injury. Furthermore, I observed significant changes in the expression of the cytokine IL6, a known regulator of proliferation of cholangiocytes and hepatocytes. I utilized the Foxl1Cre mouse model in order to identify the Foxl1 expressing cell type in the liver to further my understanding of role of Foxl1 in the liver following injury. The results from my genetic lineage tracing experiment shows a similar expression pattern to that of a ductular reaction and strongly suggests that the early Foxl1Cre lineage cell gives rise to both cholangiocytes and hepatocytes following cholestatic liver injury. Although further investigation is required, these studies will continue to elucidate the role of Foxl1 in the liver and continue to promote our understanding of liver response to injury

Impaired male fertility and atrophy of seminiferous tubules caused by haploinsufficiency for Foxa3

AbstractFoxa1, 2 and 3 (formerly HNF-3α, -β and -γ) constitute a sub-family of winged helix transcription factors with multiple roles in mammalian organ development. While all three Foxa mRNAs are present in endoderm derivatives including liver and pancreas, only Foxa3 is expressed in the testis. Here we demonstrate by genetic lineage tracing that Foxa3 is expressed in postmeiotic germ and interstitial Leydig cells. The germinal epithelium of Foxa3-deficient testes is characterized by a loss of germ cells secondary to an increase in germ cell apoptosis that ultimately leads to a Sertoli cell-only syndrome. Remarkably, not only the Foxa3−/− mice but also Foxa3+/− mice exhibited loss of germ cells. This cellular phenotype caused significantly reduced fertility and testis weight of both Foxa3−/− and Foxa3+/− mice. Using microarray analysis, we found a dramatic downregulation of the zinc finger protein 93 and the testicular tumor-associated paraneoplastic Ma antigen (PNMA) and increased expression of a number of genes including zinc finger protein 94 and several kallikrein 1-related peptidases which could account for at least part of the observed phenotype. In summary, we have identified Foxa3 as a transcriptional regulator with a dominant phenotype in germ cell maintenance and suggest FOXA3 as a potential candidate gene for subfertility in man

Foxl1 is a mesenchymal Modifier of Min in carcinogenesis of stomach and colon

Constitutive activation of the Wnt/APC/β-catenin pathway is a frequent initiating event in gastrointestinal carcinogenesis. Mutations in the Adenomatous Polyposis Coli (APC) gene up-regulate Wnt signaling by stabilizing β-catenin and causing activation of targets important in proliferation control. Here we show that loss of the mesenchymal transcription factor Foxl1 leads to a marked increase in tumor multiplicity in the colon of Apc(Min) mice. Apc(Min/+);Foxl1(-/-) mice also develop gastric tumors not observed in Apc(Min) mice. These effects are caused by earlier tumor initiation due to accelerated loss of heterozygosity (LOH) at the Apc locus. Foxl1 is the first mesenchymal Modifier of Min and plays a key role in gastrointestinal tumorigenesis