The role of the embryonic microenvironment in hematopoietic cell development

The adult hematopoietic system is comprised of a hierarchy of cells with the hematopoietic stem cell (HSC) at its foundation. HSCs give rise to progenitors that differentiate into mature hematopoietic cells, which perform the physiological functions of the hematopoietic system. The mature hematopoietic cells have a limited life span and need to be continuously replaced during adult life through the differentiation of HSCs. However, the pool of HSCs also has to be kept intact. The decision whether a dividing HSC differentiates towards a mature hematopoietic cell or preserves it self in an undifferentiated state is a tightly regulated process. An important player in this regulation is the so-called microenvironment (cells surrounding the HSCs). The adult hematopoietic system resides mainly within the bone marrow microenvironment. The hematopoietic supportive microenvironment changes during the development of an organism. Within the embryo the first HSCs are generated in close association with the dorsal aorta (major blood vessel). The dorsal aorta is part of a larger structure referred to as the aorta-gonad-mesonephros (AGM) region. During later stages in development, HSCs are found in the yolk sac, placenta and fetal liver. The fetal liver will eventually harbour the HSCs until birth when they colonize the bone marrow. All these hematopoietic tissues are believed to provide a specialized microenvironment for the generation, expansion and/or maintenance of HSCs. Despite the fact that new insights into the interactions of HSCs and the bone marrow microenvironment have been revealed in the last few years, the interplay between the embryonic microenvironment and the HSCs remains under intensive investigation. To bette! r understand how HSCs communicate with the microenvironments we studied the role of growth factors FGFs and IL-1 and the Runx1 transcription factor in the HSC supportive microenvironments provided by embryonic cell lines and embryos. As an interesting family of growth factors, the Fibroblast Growth Factors (FGFs) have previously been implicated to play a role in the communication between the bone marrow microenvironment and HSCs. As described in chapter 2, our studies showed that FGFs not only influence adult hematopoiesis, but are also regulators of embryonic hematopoiesis. More specifically, FGFs influence the supportive capacities of the AGM microenvironment for hematopoietic progenitors. As it is known that inbred mouse strains differ in HSC pool size as well as cycling activity, we compared the effects of FGFs on the bone marrow supportive microenvironment in six mouse strains. We showed that indeed there are strain-specific hematopoieticThe full text of this item cannot yet be made available, due to a publisher's embarg

Participeren moet je organiseren:onderzoek naar de participatie van cliënten bij De Zijlen die kleinschalig wonen in de wijk

De Zijlen is een organisatie die zich inzet voor zo’n 1000 mensen (kinderen, jongeren en volwassenen) met een verstandelijke beperking. Vanaf 2005 is bij De Zijlen een belangrijke verhuisbeweging gestart, waarbij cliënten met een verstandelijke beperking van het instellingsterrein “Sintmaheerdt” in Tolbert en “Groot Bronswijk” in Wagenborgen, verhuisd zijn naar kleinschaliger woonlocaties. Dit onderzoek is een vervolg op het onderzoek ”Op weg naar een nieuwe woning” (Emmens, van der Meulen, Wallenburg & Terpstra, 2010). In dit vervolgonderzoek zijn hierbij ook ervaringen van cliënten van Groot Bronswijk meegenomen. Bij De Zijlen vindt men het belangrijk dat iedere cliënt zijn of haar eigen plek inneemt in de maatschappij. Maatschappelijke participatie is een van de kernthema’s binnen De Zijlen. In de visie van De Zijlen worden verder als kernthema’s keuzevrijheid, privacy en relatievorming genoemd. Door het management van De Zijlen is aan het lectoraat Rehabilitatie van de Hanzehogeschool Groningen gevraagd om te onderzoeken welke resultaten deze verhuizingen hebben opgeleverd. In hoeverre heeft het deconcentratieproces geleid tot verbetering van de kwaliteit van leven en tot participatie in de wijk? In deze samenvatting komen achtereenvolgens de achtergrond, de onderzoeksvraag, de opzet van het onderzoek, de uitkomsten en de aanbevelingen aan bod

Physiological tonicity improves human chondrogenic marker expression through nuclear factor of activated T-cells 5 in vitro

Abstract Introduction: Chondrocytes experience a hypertonic environment compared to plasma (280 mOsm) due to the high fixed negative charge density of cartilage. Standard isolation of chondrocytes removes their hypertonic matrix, exposing them to non-physiological conditions. During in-vitro expansion, chondrocytes quickly lose their specialized phenotype, making them inappropriate for cell-based regenerative strategies. We aimed to elucidate the effects of tonicity during isolation and in-vitro expansion on chondrocyte phenotype. Methods: Human articular chondrocytes were isolated and subsequently expanded at control tonicity (280 mOsm) or at moderately elevated, physiological, tonicity (380 mOsm). The effects of physiological tonicity on chondrocyte proliferation and chondrogenic marker expression were evaluated. The role of Tonicity-responsive Enhancer Binding Protein (TonEBP/NFAT5) in response to physiological tonicity was investigated using nuclear factor of activated T-cells 5 (NFAT5) RNA interference. Results: Moderately elevated, physiological, tonicity (380 mOsm) did not affect chondrocyte proliferation, while higher tonicities inhibited proliferation and diminished cell viability. Physiological tonicity improved expression of chondrogenic markers and NFAT5 and its target genes, while suppressing dedifferentiation marker collagen type I and improving type II/type I expression ratios >100-fold. Effects of physiological tonicity were similar in osteoarthritic and ‘normal’ (non-osteoarthritic) chondrocytes, indicating a disease-independent mechanism. NFAT5 RNA interference abolished tonicity-mediated effects and revealed that NFAT5 positively regulates collagen type II expression, while suppressing type I. Conclusions: Physiological tonicity provides a simple, yet effective, means to improve phenotypical characteristics during cytokine-free isolation and in-vitro expansion of human articular chondrocytes. Our findings will lead to the development of improved cell-based repair strategies for chondral lesions and provides important insights into mechanisms underlying osteoarthritic progression

Current practice of first-trimester ultrasound screening for structural fetal anomalies in developed countries

Objectives: First-trimester ultrasound screening is increasingly performed to detect fetal anomalies early in pregnancy, aiming to enhance reproductive autonomy for future parents. This study aims to display the current practice of first-trimester ultrasound screening in developed countries. Method: An online survey among 47 prenatal screening experts in developed countries. Results: First-trimester structural anomaly screening is available in 30 of the 33 countries and is mostly offered to all women with generally high uptakes. National protocols are available in 23/30 (76.7%) countries, but the extent of anatomy assessment varies. Monitoring of scan quality occurs in 43.3% of the countries. 23/43 (53.5%) of the respondents considered the quality of first-trimester ultrasound screening unequal in different regions of their country. Conclusions: First-trimester screening for structural fetal anomalies is widely offered in developed countries, but large differences are reported in availability and use of screening protocols, the extent of anatomy assessment, training and experience of sonographers and quality monitoring systems. Consequently, this results in an unequal offer to parents in developed countries, sometimes even within the same country. Furthermore, as offer and execution differ widely, this has to be taken into account when results of screening policies are scientifically published or compared.</p

Informed choice and routinization of the second-trimester anomaly scan: a national cohort study in the Netherlands

Background: Since 2007 all pregnant women in the Netherlands are offered the second-trimester anomaly scan (SAS) in a nationwide prenatal screening program. This study aims to assess the level of informed choice of women opting for the SAS and to evaluate the presence of routinization 16 years after its implementation. It further explores decisional conflict and women’s decision making. Methods: This prospective national survey study consisted of an online questionnaire which was completed after prenatal counseling and before undergoing the SAS. Informed choice was measured by the adapted multidimensional measure of informed choice (MMIC) and was defined in case women were classified as value-consistent, if their decision for the SAS was deliberated and made with sufficient knowledge. Results: A total of 894/1167 (76.6%) women completed the questionnaire. Overall, 54.8% made an informed choice, 89.6% had good knowledge, 59.8% had deliberated their choice and 92.7% held a positive attitude towards the SAS. Women with low educational attainment (p=0.004) or respondents of non-Western descent (p=0.038) were less likely to make an informed choice. Decisional conflict was low, with a significantly lower decisional conflict score in women that made an informed choice (p<0.001). Most respondents (97.9%) did not perceive pressure to undergo the SAS. Conclusions: Our study showed a relatively low rate of informed choice for the SAS, due to absence of deliberation. Therefore, some routinization seem to be present in the Netherlands. However, most women had sufficient knowledge, did not perceive pressure and experienced low decisional conflict

Is there still a role for nuchal translucency measurement in the changing paradigm of first trimester screening?

Objectives: To give an overview of the genetic and structural abnormalities occurring in fetuses with nuchal translucency (NT) measurement exceeding the 95th percentile at first-trimester screening and to investigate which of these abnormalities would be missed if cell-free fetal DNA (cfDNA) were used as a first-tier screening test for chromosomal abnormalities. Methods: This is a national study including 1901 pregnancies with NT≥95th percentile referred to seven university hospitals in the Netherlands between 1 January 2010 and 1 January 2016. All cases with unknown pregnancy outcome were excluded. Results of detailed ultrasound examinations, karyotyping, genotyping, pregnancy and neonatal outcomes, investigation by a clinical geneticist and post-mortem investigations were collected. Results: In total, 821 (43%) pregnancies had at least one abnormality. The rate of abnormalities was 21% for fetuses with NT between 95th and 99th percentile and 62% for fetuses with NT≥99th percentile. Prevalence of single-gene disorders, submicroscopic, chromosomal and structural abnormalities was 2%, 2%, 30% and 9%, respectively. Conclusion: Although cfDNA is superior to the combined test, especially for the detection of trisomy 21, 34% of the congenital abnormalities occurring in fetuses with increased NT may remain undetected in the first trimester of pregnancy, unless cfDNA is used in combination with fetal sonographic assessment, including NT measurement

Current practice of first-trimester ultrasound screening for structural fetal anomalies in developed countries

OBJECTIVES: First-trimester ultrasound screening is increasingly performed to detect fetal anomalies early in pregnancy, aiming to enhance reproductive autonomy for future parents. This study aims to display the current practice of first-trimester ultrasound screening in developed countries. METHOD: An online survey among 47 prenatal screening experts in developed countries. RESULTS: First-trimester structural anomaly screening is available in 30 of the 33 countries and is mostly offered to all women with generally high uptakes. National protocols are available in 23/30 (76.7%) countries, but the extent of anatomy assessment varies. Monitoring of scan quality occurs in 43.3% of the countries. 23/43 (53.5%) of the respondents considered the quality of first-trimester ultrasound screening unequal in different regions of their country. CONCLUSIONS: First-trimester screening for structural fetal anomalies is widely offered in developed countries, but large differences are reported in availability and use of screening protocols, the extent of anatomy assessment, training and experience of sonographers and quality monitoring systems. Consequently, this results in an unequal offer to parents in developed countries, sometimes even within the same country. Furthermore, as offer and execution differ widely, this has to be taken into account when results of screening policies are scientifically published or compared

Correction: Protocol of the Healthy Brain Study:An accessible resource for understanding the human brain and how it dynamically and individually operates in its bio-social context

[This corrects the article DOI: 10.1371/journal.pone.0260952.]

Heat Shock Protein 90 as a Prognostic Marker and Therapeutic Target for Adrenocortical Carcinoma

Background: Adrenocortical carcinoma (ACC) is a rare tumor entity with restricted therapeutic opportunities. HSP90 (Heat Shock Protein 90) chaperone activity is fundamental for cell survival and contributes to different oncogenic signaling pathways. Indeed, agents targeting HSP90 function have shown therapeutic efficacy in several cancer types. We have examined the expression of HSP90 in different adrenal tumors and evaluated the use of HSP90 inhibitors in vitro as possible therapy for ACC. Methods: Immunohistochemical expression of HSP90 isoforms was investigated in different adrenocortical tumors and associated with clinical features. Additionally, a panel of N-terminal (17-allylamino-17-demethoxygeldanamycin (17-AAG), luminespib, and ganetespib) and C-terminal (novobiocin and silibinin) HSP90 inhibitors were tested on various ACC cell lines. Results: Within adrenocortical tumors, ACC samples exhibited the highest expression of HSP90β. Within a cohort of ACC patients, HSP90β expression levels were inversely correlated with recurrence-free and overall survival. In functional assays, among five different compounds tested luminespib and ganetespib induced a significant decrease in cell viability in single as well as in combined treatments with compounds of the clinically used EDP-M scheme (etoposide, doxorubicin, cisplatin, mitotane). Inhibition of cell viability correlated furthermore with a decrease in proliferation, in cell migration and an increase in apoptosis. Moreover, analysis of cancer pathways indicated a modulation of the ERK1/2—and AKT—pathways by luminespib and ganetespib treatment. Conclusions: Our findings emphasize HSP90 as a marker with prognostic impact and promising target with N-terminal HSP90 inhibitors as drugs with potential therapeutic efficacy toward ACC