Foxg1 is required to limit the formation of ciliary margin tissue and Wnt/β-catenin signalling in the developing nasal retina of the mouse

AbstractThe ciliary margin (CM) develops in the peripheral retina and gives rise to the iris and the ciliary body. The Wnt/β-catenin signalling pathway has been implicated in ciliary margin development. Here, we tested the hypothesis that in the developing mouse retina Foxg1 is responsible for suppressing the Wnt/β-catenin pathway and restricting CM development. We showed that there is excess CM tissue in Foxg1−/− null embryos and this expansion is more pronounced in the nasal retina where Foxg1 normally shows its highest expression levels. Results on expression of a reporter allele for Wnt/β-catenin signalling and of Lef1, a target of Wnt/β-catenin signalling, displayed significant upregulation of this pathway in Foxg1−/− nulls at embryonic days 12.5 and 14.5. Interestingly, this upregulation was observed specifically in the nasal retina, where normally very few Wnt-responsive cells are observed. These results indicate a suppressive role of Foxg1 on this signalling pathway. Our results reveal a new role of Foxg1 in limiting CM development in the nasal peripheral retina and add a new molecular player in the developmental network involved in CM specification

Abnormal positioning of diencephalic cell types in neocortical tissue in the dorsal telencephalon of mice lacking functional Gli3

The transcription factor Gli3 (glioma-associated oncogene homolog) is essential for normal development of the mammalian forebrain. One extreme requirement for Gli3 is at the dorsomedial telencephalon, which does not form in Gli3(Xt/Xt) mutant mice lacking functional Gli3. In this study, we analyzed expression of Gli3 in the wild-type telencephalon and observed a (high)dorsal-to-(low)ventral gradient of Gli3 expression and predominance of the cleaved form of the Gli3 protein dorsally. This graded expression correlates with the (severe)dorsal-to-(mild)ventral telencephalic phenotype observed in Gli3(Xt/Xt) mice. We characterized the abnormal joining of the telencephalon to the diencephalon and defined the medial limit of the dorsal telencephalon in Gli3(Xt/Xt) mice early in corticogenesis. Based on this analysis, we concluded that some of the abnormal expression of ventral telencephalic markers previously described as being in the dorsal telencephalon is, in fact, expression in adjacent diencephalic tissue, which expresses many of the same genes that mark the ventral telencephalon. We observed occasional cells with diencephalic character in the Foxg1 (forkhead box)-expressing Gli3(Xt/Xt) telencephalon at embryonic day 10.5, a day after the anatomical subdivision of the forebrain vesicle. Large clusters of such cells appear in the Gli3(Xt/Xt) neocortical region at later ages, when the neocortex becomes highly disorganized, forming rosettes comprising mainly neural progenitors. We propose that Gli3 is indispensable for formation of an intact telencephalic-diencephalic boundary and for preventing the abnormal positioning of diencephalic cells in the dorsal telencephalon

Impaired spatial learning strategies and novel object recognition in mice haploinsufficient for the dual specificity tyrosine-regulated kinase-1A (Dyrk1A)

BACKGROUND: Pathogenic aneuploidies involve the concept of dosage-sensitive genes leading to over- and underexpression phenotypes. Monosomy 21 in human leads to mental retardation and skeletal, immune and respiratory function disturbances. Most of the human condition corresponds to partial monosomies suggesting that critical haploinsufficient genes may be responsible for the phenotypes. The DYRK1A gene is localized on the human chromosome 21q22.2 region, and has been proposed to participate in monosomy 21 phenotypes. It encodes a dual-specificity kinase involved in neuronal development and in adult brain physiology, but its possible role as critical haploinsufficient gene in cognitive function has not been explored. METHODOLOGY/PRINCIPAL FINDINGS: We used mice heterozygous for a Dyrk1A targeted mutation (Dyrk1A+/−) to investigate the implication of this gene in the cognitive phenotypes of monosomy 21. Performance of Dyrk1A+/− mice was assayed 1/ in a navigational task using the standard hippocampally related version of the Morris water maze, 2/ in a swimming test designed to reveal potential kinesthetic and stress-related behavioral differences between control and heterozygous mice under two levels of aversiveness (25°C and 17°C) and 3/ in a long-term novel object recognition task, sensitive to hippocampal damage. Dyrk1A+/− mice showed impairment in the development of spatial learning strategies in a hippocampally-dependent memory task, they were impaired in their novel object recognition ability and were more sensitive to aversive conditions in the swimming test than euploid control animals. CONCLUSIONS/SIGNIFICANCE: The present results are clear examples where removal of a single gene has a profound effect on phenotype and indicate that haploinsufficiency of DYRK1A might contribute to an impairment of cognitive functions and stress coping behavior in human monosomy 21

Dyrk1A haploinsufficiency affects viability and causes developmental delay and abnormal brain morphology in mice

DYRK1A is the human orthologue of the Drosophila minibrain (mnb) gene, which is involved in postembryonic neurogenesis in flies. Because of its mapping position on chromosome 21 and the neurobehavioral alterations shown by mice overexpressing this gene, involvement of DYRK1A in some of the neurological defects of Down syndrome patients has been suggested. To gain insight into its physiological role, we have generated mice deficient in Dyrk1A function by gene targeting. Dyrk1A(−/−) null mutants presented a general growth delay and died during midgestation. Mice heterozygous for the mutation (Dyrk1A(+/−)) showed decreased neonatal viability and a significant body size reduction from birth to adulthood. General neurobehavioral analysis revealed preweaning developmental delay of Dyrk1A(+/−) mice and specific alterations in adults. Brains of Dyrk1A(+/−) mice were decreased in size in a region-specific manner, although the cytoarchitecture and neuronal components in most areas were not altered. Cell counts showed increased neuronal densities in some brain regions and a specific decrease in the number of neurons in the superior colliculus, which exhibited a significant size reduction. These data provide evidence about the nonredundant, vital role of Dyrk1A and suggest a conserved mode of action that determines normal growth and brain size in both mice and flies

A European survey on the insights of patients living with metastatic colorectal cancer: the patient journey before, during and after diagnosis - an Eastern European perspective

Background: Despite being highly preventable and treatable if diagnosed early, colorectal cancer (CRC) remains the second leading cause of cancer-related death in Europe. Limited information is available from the patient perspective on the persisting unmet needs of the journey of the patient with CRC. Objective: To capture European metastatic CRC (mCRC) patients' insights during the patient journey (prediagnosis; diagnosis; postdiagnosis) through a patient survey. Methods: In total, 883 patients from 15 European countries participated. Participants were divided into four groups from Hungary, Poland, Serbia and 'other European countries' (n=103, 163, 170 and 447 patients, respectively). Results: General awareness of CRC and its symptoms prediagnosis varied among groups, with patients from Poland recording the lowest levels. Screening practices and attitudes also varied; while more patients from Serbia had been invited to CRC screening (~15%) compared with the other groups, the ones not invited claimed mostly (~20%) that would not have attended if they had been invited. Whereas most patients were diagnosed within a month after the first consultation/positive screening, the percentages varied substantially being lowest among patients in Poland (~30%) and Serbia (~25%). Although CRC-related information provision varied, with most informed patients from Hungary (~90%) and least from Serbia (~50%), all groups requested an easier-to-understand language by the healthcare team. Approximately 50% of patients from Eastern Europe had to wait longer than a month to receive treatment, in contrast to ~30% from other European countries. All groups emphasised the unmet need for support from psychologists and other patients. Conclusions: Our survey reveals the key aspects of the journey of the patient with mCRC and highlights the areas of similarities and differences between patients with mCRC from Eastern Europe versus those from other European countries as well as among patients from different Eastern European countries, calling for improvement particularly around awareness, screening, treatment availability, communication and support networks

The molecular and cellular signatures of the mouse eminentia thalami support its role as a signalling centre in the developing forebrain

The mammalian eminentia thalami (EmT) (or thalamic eminence) is an embryonic forebrain structure of unknown function. Here, we examined the molecular and cellular properties of the mouse EmT. We first studied mRNA expression of signalling molecules and found that the EmT is a structure, rich in expression of secreted factors, with Wnts being the most abundantly detected. We then examined whether EmT tissue could induce cell fate changes when grafted ectopically. For this, we transplanted EmT tissue from a tau-GFP mouse to the ventral telencephalon of a wild type host, a telencephalic region where Wnt signalling is not normally active but which we showed in culture experiments is competent to respond to Wnts. We observed that the EmT was able to induce in adjacent ventral telencephalic cells ectopic expression of Lef1, a transcriptional activator and a target gene of the Wnt/β-catenin pathway. These Lef1-positive;GFP-negative cells expressed the telencephalic marker Foxg1 but not Ascl1, which is normally expressed by ventral telencephalic cells. These results suggest that the EmT has the capacity to activate Wnt/β-catenin signalling in the ventral telencephalon and to suppress ventral telencephalic gene expression. Altogether, our data support a role of the EmT as a signalling centre in the developing mouse forebrain. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00429-015-1127-3) contains supplementary material, which is available to authorized users

Bringing onco‐innovation to Europe’s healthcare systems: The potential of biomarker testing, real world evidence, tumour agnostic therapies to empower personalised medicine

Rapid and continuing advances in biomarker testing are not being matched by uptake in health systems, and this is hampering both patient care and innovation. It also risks costing health systems the opportunity to make their services more efficient and, over time, more economical. The potential that genomics has brought to biomarker testing in diagnosis, prediction and research is being realised, pre‐eminently in many cancers, but also in an ever‐wider range of conditions— notably BRCA1/2 testing in ovarian, breast, pancreatic and prostate cancers. Nevertheless, the implementation of genetic testing in clinical routine setting is still challenging. Development is impeded by country‐related heterogeneity, data deficiencies, and lack of policy alignment on standards, approval—and the role of real‐world evidence in the process—and reimbursement. The acute nature of the problem is compellingly illustrated by the particular challenges facing the development and use of tumour agnostic therapies, where the gaps in preparedness for taking advantage of this innovative approach to cancer therapy are sharply exposed. Europe should already have in place a guarantee of universal access to a minimum suite of biomarker tests and should be planning for an optimum testing scenario with a wider range of biomarker tests integrated into a more sophisticated health system articulated around personalised medicine. Improving healthcare and winning advantages for Europe’s industrial competitiveness and innovation require an appropriate policy framework—starting with an update to outdated recommendations. We show herein the main issues and proposals that emerged during the previous advisory boards organised by the European Alliance for Personalized Medicine which mainly focus on possible scenarios of harmonisation of both oncogenetic testing and management of cancer patients

Role of Gli3 in the developing mouse forebrain

The mammalian forebrain, which consists of the telencephalon and the diencephalon, is responsible for many higher cognitive functions such as thinking, learning and memory. The cerebral cortex, which is important for language and processing information, is located in the dorsal portion of the telencephalon. The basal ganglia, which are important for movement, are located in the ventral telencephalon. Many genes are involved in patterning and the development of the forebrain. One gene that appears to be crucial for forebrain development is Gli3. Gli3 has been shown to work as both a transcriptional activator and a repressor of the Sonic Hedgehog (Shh) signalling pathway in the developing spinal cord and limb buds. In the telencephalon, Shh has been shown to be important for induction of ventral cell fate, but the exact function of Gli3 in the forebrain and the interactions between Gli3 and Shh are still obscure. Previous studies have shown that Gli3 is required for the formation of the cortical hem area of the telencephalon, which does not form in Gli3Xt/Xt mutant mice lacking functional Gli3. The residual dorsal telencephalon of the Gli3Xt/Xt mutants is partially ‘ventralized’. The main aim of this study was to re-examine the developing forebrain of Gli3Xt/Xt mouse mutants to gain insight into the function of Gli3 during forebrain development. In this thesis, the expression of Gli3 mRNA and protein was examined in the E12.5 and E14.5 wild type telencephalon. The highdorsal-to-lowventral expression pattern of Gli3 corresponds to severedorsal-to-mildventral defects observed in the Gli3Xt/Xt mutants. The ratios between the levels of the cleaved and full length isoforms of Gli3 in dorsal and ventral telencephalon resemble those described in dorsal and ventral spinal cord and in the anterior and posterior limb bud, respectively, suggesting Gli3 in the dorsal telencephalon may act as a repressor of the Shh signalling pathway. The total amount and the ratios of the two isoforms of Gli3 protein were examined in Shh and Foxg1 null mice, which lack ventral telencephalon. The results obtained agree with a role of Gli3 as a repressor of the Shh pathway in the dorsal telencephalon. The forebrains of Gli3Xt/Xt mutants were analysed systematically both anatomically and by molecular markers in this thesis. The border between the telencephalon and the diencephalon was delineated in the Gli3Xt/Xt mutants by using a combination of markers expressed in different areas within the forebrain. This lead to the observation that the previously reported ‘ventralization’ only occurred in the very rostral telencephalic sections of the Gli3Xt/Xt mutant embryos, suggesting a possible shape change of the Gli3Xt/Xt telencephalon. To examine the possible causes of the significant size reduction of Gli3Xt/Xt mutant telencephalon compared to wild type telencephalon from E10.5, cell proliferation and cell death properties studies were undertaken. The changes observed were not sufficient to explain the phenotypic differences between the Gli3Xt/Xt mutant and the wild type embryos indicating that they might be the result of an early patterning defect. The dorsal telencephalon is severely reduced in volume at both E12.5 and E10.5, containing cells from adjacent eminentia thalami, probably due to the loss of the dorso-medial telencephalon. Large clusters of eminentia thalami cells were observed at later developmental stages, when the neocortex becomes highly disorganized, forming rosettes comprising mainly neural progenitors. These results suggest Gli3 is important for the formation of an intact telencephalic-diencephalic boundary and for preventing the abnormal location of diencephalic cells in the dorsal telencephalon. The volume of Gli3Xt/Xt ventral telencephalon was increased compared to that of the wild types at E10.5, but became smaller than that of the wild type littermates at E12.5. This might have been the result of a combination of more cells exiting the cell cycle and increased cell death observed in the Gli3Xt/Xt ventral telencephalon at E10.5, suggesting Gli3 regulates cell differentiation and cell death properties at this age and brain region. The significant expansion of rostro-ventral telencephalon observed in the Gli3Xt/Xt mutant might correlate with the expansion of Fgf8 expression and this hypothesis has been tested in this thesis.EThOS - Electronic Theses Online ServiceGBUnited Kingdo