105 research outputs found
The multispecific thyroid hormone transporter OATP1C1 mediates cell-specific sulforhodamine 101-labeling of hippocampal astrocytes
Sulforhodamine 101 (SR101) is widely used for astrocyte identification, though the labeling mechanism remains unknown and the efficacy of labeling in different brain regions is heterogeneous. By combining region-specific isolation of astrocytes followed by transcriptome analysis, two-photon excitation microscopy, and mouse genetics, we identified the thyroid hormone transporter OATP1C1 as the SR101-uptake transporter in hippocampus and cortex. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00429-013-0645-0) contains supplementary material, which is available to authorized users
Revisiting unstable disability and the fluctuations of frailty: a measurement burst approach
Background
It has been hypothesised that frailty is the root cause of clinically observed but rarely systematically measured unstable disability among older adults. In this study, we measure the extent of short-term disability fluctuations and estimate their association with frailty using intensive longitudinal data.
Methods
Repeated measurements of disability were collected under a measurement burst design in the FRequent health Assessment In Later life (FRAIL70+) study. A total of 426 community-dwelling older adults (70+) in Austria were interviewed about difficulties with basic, instrumental and mobility-related activities of daily living biweekly up to a total of 14 times in two measurement bursts (2891 and 2192 observations). Baseline frailty was assessed with both physical frailty (FP) and the frailty index (FI). Disability fluctuations were measured with the intra-individual interquartile range (iIQR) and estimated with a two-step generalised mixed regression procedure.
Results
Fewer participants were frail at baseline according to FP (11%) than FI (32%). Frail study participants reported not only more severe disability but also had more short-term disability fluctuations (iIQR = 1.0–1.5) compared with their robust counterparts (iIQR = 0). Regression models indicated that baseline frailty was associated with 2–3 times larger short-term disability fluctuations, which were also more prevalent among women, and increased with age and disability severity.
Conclusion
Compared with those who were robust, frail older adults were characterised by not only more severe but also more unstable disability. Short-term disability fluctuations are closely tied to disability severity. Future studies should assess both stressors that may cause disability fluctuations among frail older adults as well as their potential consequences to inform frailty-centred care
Transcriptomics reveal an integrative role for maternal thyroid hormones during zebrafish embryogenesis
Thyroid hormones (THs) are essential for embryonic brain development but the genetic mechanisms involved in the action of maternal THs (MTHs) are still largely unknown. As the basis for understanding the underlying genetic mechanisms of MTHs regulation we used an established zebrafish monocarboxylic acid transporter 8 (MCT8) knock-down model and characterised the transcriptome in 25hpf zebrafish embryos. Subsequent mapping of differentially expressed genes using Reactome pathway analysis together with in situ expression analysis and immunohistochemistry revealed the genetic networks and cells under MTHs regulation during zebrafish embryogenesis. We found 4,343 differentially expressed genes and the Reactome pathway analysis revealed that TH is involved in 1681 of these pathways. MTHs regulated the expression of core developmental pathways, such as NOTCH and WNT in a cell specific context. The cellular distribution of neural MTH-target genes demonstrated their cell specific action on neural stem cells and differentiated neuron classes. Taken together our data show that MTHs have a role in zebrafish neurogenesis and suggest they may be involved in cross talk between key pathways in neural development. Given that the observed MCT8 zebrafish knockdown phenotype resembles the symptoms in human patients with Allan-Herndon-Dudley syndrome our data open a window into understanding the genetics of this human congenital condition.Portuguese Fundacao para Ciencia e Tecnologia (FCT) [PTDC/EXPL/MARBIO/0430/2013]; CCMAR FCT Plurianual financing [UID/Multi/04326/2013]; FCT [SFRH/BD/111226/2015, SFRH/BD/108842/2015, SFRH/BPD/89889/2012]; FCT-IF Starting Grant [IF/01274/2014]info:eu-repo/semantics/publishedVersio
Thyroid Hormone Transporters MCT8 and OATP1C1 Control Skeletal Muscle Regeneration
Thyroid hormone (TH) transporters are required for the transmembrane passage of TH in target cells. In humans, inactivating mutations in the TH transporter MCT8 cause the Allan-Herndon-Dudley syndrome, characterized by severe neuromuscular symptoms and an abnormal TH serum profile, which is fully replicated in Mct8 knockout mice and Mct8/Oatp1c1 double-knockout (M/O DKO) mice. Analysis of tissue TH content and expression of TH-regulated genes indicate a thyrotoxic state in Mct8-deficient skeletal muscles. Both TH transporters are upregulated in activated satellite cells (SCs). In M/O DKO mice, we observed a strongly reduced number of differentiated SCs, suggesting an impaired stem cell function. Moreover, M/O DKO mice and mice lacking both transporters exclusively in SCs showed impaired skeletal muscle regeneration. Our data provide solid evidence for a unique gate-keeper function of MCT8 and OATP1C1 in SC activation, underscoring the importance of a finely tuned TH signaling during myogenesis. In this article, Mayerl and colleagues demonstrate that the thyroid hormone transporters MCT8 and OATP1C1 are unique gate-keepers in activated muscle stem cells. The expression of both transporters increases upon activation of muscle stem cells, while loss of MCT8 and OATP1C1 expression results in impaired muscle stem cell differentiation
Macroevolutionary diversification of glands for chemical communication in squamate reptiles
Chemical communication plays a central role in social, sexual and ecological interactions among animals. However, the macroevolutionary diversification of traits responsible for chemical signaling remains fundamentally unknown. Most research investigating evolutionary diversification of glands responsible for the production of chemical signals has focused on arthropods, while its study among vertebrates remains neglected. Using a global-scale dataset covering > 80% (7,904 species) of the living diversity of lizards and snakes (squamates), we investigate rates, trajectories and phylogenetic patterns of diversification of their follicular glands for chemical communication. We observed these glands in 13.66% of species, that their expression has varying phylogenetic signal among lineages, and that the crown squamate ancestor lacked follicular glands, which therefore originated and diversified subsequently during their evolutionary history. Additionally, our findings challenge the longstanding view that within squamates the Iguania are visually oriented while Scleroglossa are chemically-oriented, given that Iguania doubles Scleroglossa in the frequency of glands. Our phylogenetic analyses identified stabilizing selection as the best model describing follicular gland diversification, and revealed high rates of disparity. We provide the first global-scale analysis investigating the diversification of one of the main forms of communication among reptiles, presenting a macroevolutionary angle to questions traditionally explored at microevolutionary scale
The effects of TNF-alpha inhibitor therapy on the incidence of infection in JIA children
Juvenile Idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood. The diagnosis is based on the underlying symptoms of arthritis with an exclusion of other diseases Biologic agents are increasingly used on the side of disease-modifying anti-rheumatic drugs (DMARD) in JIA treatment.The aim of this meta-analysis was to investigate the observed infections in JIA children during tumor necrosis factor (TNF)-alpha inhibitor therapy. A systematic search of three databases (Medline via PubMed, Embase, Cochrane Library) was carried out up to May 2018. Published trials that evaluated the infectious adverse events in patients receiving TNF-alpha inhibitor vs. a control group were included in the analysis. Full-text data extraction was carried out independently by the investigators from ten relevant publications. 1434 patients received TNF-alpha inhibitor therapy; the control group consisted of 696 subjects. The analysis presented the risk of infection in the active treatment group (OR = 1.13; 95% CI: 0.76-1.69; p = 0.543). The majority of infections were upper respiratory tract infections (URTIs). Furthermore, the subgroup analysis demonstrated a higher infection rate in the observed localization.Anti-TNF therapy slightly but not significantly increases the incidence of infection in JIA children compared to other therapies (GRADE: moderate evidence). The most common infections reported were mild URTIs. Further studies with larger patients number with a strong evidence level are crucially needed to finalize the answer whether anti-TNF therapy elevates and if yes on what extent the incidence of infection in JIA children.Prospero: CRD42017067873
Familial t(1;11) translocation is associated with disruption of white matter structural integrity and oligodendrocyte–myelin dysfunction
Although the underlying neurobiology of major mental illness (MMI) remains unknown, emerging evidence implicates a role for oligodendrocyte–myelin abnormalities. Here, we took advantage of a large family carrying a balanced t(1;11) translocation, which substantially increases risk of MMI, to undertake both diffusion tensor imaging and cellular studies to evaluate the consequences of the t(1;11) translocation on white matter structural integrity and oligodendrocyte–myelin biology. This translocation disrupts among others the DISC1 gene which plays a crucial role in brain development. We show that translocation-carrying patients display significant disruption of white matter integrity compared with familial controls. At a cellular level, we observe dysregulation of key pathways controlling oligodendrocyte development and morphogenesis in induced pluripotent stem cell (iPSC) derived case oligodendrocytes. This is associated with reduced proliferation and a stunted morphology in vitro. Further, myelin internodes in a humanized mouse model that recapitulates the human translocation as well as after transplantation of t(1;11) oligodendrocyte progenitors were significantly reduced when compared with controls. Thus we provide evidence that the t(1;11) translocation has biological effects at both the systems and cellular level that together suggest oligodendrocyte–myelin dysfunction
Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty
This study explores how researchers’ analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers’ expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team’s workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers’ results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings
The Crowdsourced Replication Initiative: Investigating Immigration and Social Policy Preferences. Executive Report.
In an era of mass migration, social scientists, populist parties and social movements raise concerns over the future of immigration-destination societies. What impacts does this have on policy and social solidarity? Comparative cross-national research, relying mostly on secondary data, has findings in different directions. There is a threat of selective model reporting and lack of replicability. The heterogeneity of countries obscures attempts to clearly define data-generating models. P-hacking and HARKing lurk among standard research practices in this area.This project employs crowdsourcing to address these issues. It draws on replication, deliberation, meta-analysis and harnessing the power of many minds at once. The Crowdsourced Replication Initiative carries two main goals, (a) to better investigate the linkage between immigration and social policy preferences across countries, and (b) to develop crowdsourcing as a social science method. The Executive Report provides short reviews of the area of social policy preferences and immigration, and the methods and impetus behind crowdsourcing plus a description of the entire project. Three main areas of findings will appear in three papers, that are registered as PAPs or in process
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