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Developmental Biology
Signaling Dynamics Control Cell Fate in the Early Drosophila Embryo.
Feb 12, 2019   Developmental Cell
Johnson HE, Toettcher JE
Signaling Dynamics Control Cell Fate in the Early Drosophila Embryo.
Feb 12, 2019
Developmental Cell
The Erk mitogen-activated protein kinase plays diverse roles in animal development. Its widespread reuse raises a conundrum: when a single kinase like Erk is activated, how does a developing cell know which fate to adopt? We combine optogenetic control with genetic perturbations to dissect Erk-dependent fates in the early Drosophila embryo. We find that Erk activity is sufficient to "posteriorize" 88% of the embryo, inducing gut endoderm-like gene expression and morphogenetic movements in all cells within this region. Gut endoderm fate adoption requires at least 1 h of signaling, whereas a 30-min Erk pulse specifies a distinct ectodermal cell type, intermediate neuroblasts. We find that the endoderm-ectoderm cell fate switch is controlled by the cumulative load of Erk activity, not the duration of a single pulse. The fly embryo thus harbors a classic example of dynamic control, where the temporal profile of Erk signaling selects between distinct physiological outcomes.
Nr2f-dependent allocation of ventricular cardiomyocyte and pharyngeal muscle progenitors.
Feb 15, 2019   PLoS Genetics
Dohn TE, Ravisankar P, Tirera FT, Martin KE, Gafranek JT, Duong TB, VanDyke TL, Touvron M, Barske LA, Crump JG, Waxman JS
Nr2f-dependent allocation of ventricular cardiomyocyte and pharyngeal muscle progenitors.
Feb 15, 2019
PLoS Genetics
Multiple syndromes share congenital heart and craniofacial muscle defects, indicating there is an intimate relationship between the adjacent cardiac and pharyngeal muscle (PM) progenitor fields. However, mechanisms that direct antagonistic lineage decisions of the cardiac and PM progenitors within the anterior mesoderm of vertebrates are not understood. Here, we identify that retinoic acid (RA) signaling directly promotes the expression of the transcription factor Nr2f1a within the anterior lateral plate mesoderm. Using zebrafish nr2f1a and nr2f2 mutants, we find that Nr2f1a and Nr2f2 have redundant requirements restricting ventricular cardiomyocyte (CM) number and promoting development of the posterior PMs. Cre-mediated genetic lineage tracing in nr2f1a; nr2f2 double mutants reveals that tcf21+ progenitor cells, which can give rise to ventricular CMs and PM, more frequently become ventricular CMs potentially at the expense of posterior PMs in nr2f1a; nr2f2 mutants. Our studies reveal insights into the molecular etiology that may underlie developmental syndromes that share heart, neck and facial defects as well as the phenotypic variability of congenital heart defects associated with NR2F mutations in humans.
Protocol to Generate Ureteric Bud Structures from Human iPS Cells.
Feb 11, 2019   Methods In Molecular Biology (Clifton, N.J.)
Mae SI, Ryosaka M, Osafune K
Protocol to Generate Ureteric Bud Structures from Human iPS Cells.
Feb 11, 2019
Methods In Molecular Biology (Clifton, N.J.)
The generation of ureteric bud (UB), which is the renal progenitor that gives rise to renal collecting ducts and lower urinary tract, from human-induced pluripotent stem cells (hiPSCs) provides a cell source for studying the development of UB and kidney disease. Here we describe a stepwise and efficient two-dimensional differentiation method of hiPSCs into Wolffian duct (WD) cells. We also describe how to generate three-dimensional WD epithelial structures that can differentiate into UB-like structures.
Nkx2-5 Second Heart Field Target Gene Ccdc117 Regulates DNA Metabolism and Proliferation.
Feb 16, 2019   Scientific Reports
Horton AJ, Brooker J, Streitfeld WS, Flessa ME, Pillai B, Simpson R, Clark CD, Gooz MB, Sutton KK, Foley AC, Lee KH
Nkx2-5 Second Heart Field Target Gene Ccdc117 Regulates DNA Metabolism and Proliferation.
Feb 16, 2019
Scientific Reports
The cardiac transcription factor Nkx2-5 is essential for normal outflow tract (OFT) and right ventricle (RV) development. Nkx2-5-/- null mouse embryos display severe OFT and RV hypoplasia and a single ventricle phenotype due to decreased proliferation of Second Heart Field (SHF) cells, a pool of cardiac progenitors present in anterior pharyngeal arch mesoderm at mid-gestation. However, definition of the precise role of Nkx2-5 in facilitating SHF expansion is incomplete. We have found that Nkx2-5 positively and directly regulates a novel target gene, Ccdc117, in cells of the SHF at these stages. The nuclear/mitotic spindle associated protein Ccdc117 interacts with the MIP18/MMS19 cytoplasmic iron-sulfur (FeS) cluster assembly (CIA) complex, which transfers critical FeS clusters to several key enzymes with functions in DNA repair and replication. Loss of cellular Ccdc117 expression results in reduced proliferation rates associated with a delay at the G1-S transition, decreased rates of DNA synthesis, and unresolved DNA damage. These results implicate a novel role for Nkx2-5 in the regulation of cell cycle events in the developing heart, through Ccdc117's interaction with elements of the CIA pathway and the facilitation of DNA replication during SHF expansion.
No evidence of involvement of E-cadherin in cell fate specification or the segregation of Epi and PrE in mouse blastocysts.
Feb 08, 2019   PloS One
Filimonow K, Saiz N, Suwińska A, Wyszomirski T, Grabarek JB, Ferretti E, Piliszek A, Plusa B, Maleszewski M
No evidence of involvement of E-cadherin in cell fate specification or the segregation of Epi and PrE in mouse blastocysts.
Feb 08, 2019
PloS One
During preimplantation mouse development stages, emerging pluripotent epiblast (Epi) and extraembryonic primitive endoderm (PrE) cells are first distributed in the blastocyst in a "salt-and-pepper" manner before they segregate into separate layers. As a result of segregation, PrE cells become localised on the surface of the inner cell mass (ICM), and the Epi is enclosed by the PrE on one side and by the trophectoderm on the other. During later development, a subpopulation of PrE cells migrates away from the ICM and forms the parietal endoderm (PE), while cells remaining in contact with the Epi form the visceral endoderm (VE). Here, we asked: what are the mechanisms mediating Epi and PrE cell segregation and the subsequent VE vs PE specification? Differences in cell adhesion have been proposed; however, we demonstrate that the levels of plasma membrane-bound E-cadherin (CDH1, cadherin 1) in Epi and PrE cells only differ after the segregation of these lineages within the ICM. Moreover, manipulating E-cadherin levels did not affect lineage specification or segregation, thus failing to confirm its role during these processes. Rather, we report changes in E-cadherin localisation during later PrE-to-PE transition which are accompanied by the presence of Vimentin and Twist, supporting the hypothesis that an epithelial-to-mesenchymal transition process occurs in the mouse peri-implantation blastocyst.
Cell population balance of cardiovascular spheroids derived from human induced pluripotent stem cells.
Feb 08, 2019   Scientific Reports
Yan Y, Bejoy J, Xia J, Griffin K, Guan J, Li Y
Cell population balance of cardiovascular spheroids derived from human induced pluripotent stem cells.
Feb 08, 2019
Scientific Reports
Stem cell-derived cardiomyocytes and vascular cells can be used for a variety of applications such as studying human heart development and modelling human disease in culture. In particular, protocols based on modulation of Wnt signaling were able to produce high quality of cardiomyocytes or vascular cells from human pluripotent stem cells (hPSCs). However, the mechanism behind the development of 3D cardiovascular spheroids into either vascular or cardiac cells has not been well explored. Hippo/Yes-associated protein (YAP) signaling plays important roles in the regulation of organogenesis, but its impact on cardiovascular differentiation has been less evaluated. In this study, the effects of seeding density and a change in YAP signaling on 3D cardiovascular spheroids patterning from hPSCs were evaluated. Compared to 2D culture, 3D cardiovascular spheroids exhibited higher levels of sarcomeric striations and higher length-to-width ratios of α-actinin+ cells. The spheroids with high seeding density exhibited more α-actinin+ cells and less nuclear YAP expression. The 3D cardiovascular spheroids were also treated with different small molecules, including Rho kinase inhibitor (Y27632), Cytochalasin D, Dasatinib, and Lysophosphatidic acid to modulate YAP localization. Nuclear YAP inhibition resulted in lower expression of active β-catenin, vascular marker, and MRTF, the transcription factor mediated by RhoGTPases. Y27632 also promoted the gene expression of MMP-2/-3 (matrix remodeling) and Notch-1 (Notch signaling). These results should help our understanding of the underlying effects for the efficient patterning of cardiovascular spheroids after mesoderm formation from hPSCs.
Noise-resistant developmental reproducibility in vertebrate somite formation.
Feb 16, 2019   PLoS Computational Biology
Naoki H, Akiyama R, Sari DWK, Ishii S, Bessho Y, Matsui T
Noise-resistant developmental reproducibility in vertebrate somite formation.
Feb 16, 2019
PLoS Computational Biology
The reproducibility of embryonic development is remarkable, although molecular processes are intrinsically stochastic at the single-cell level. How the multicellular system resists the inevitable noise to acquire developmental reproducibility constitutes a fundamental question in developmental biology. Toward this end, we focused on vertebrate somitogenesis as a representative system, because somites are repeatedly reproduced within a single embryo whereas such reproducibility is lost in segmentation clock gene-deficient embryos. However, the effect of noise on developmental reproducibility has not been fully investigated, because of the technical difficulty in manipulating the noise intensity in experiments. In this study, we developed a computational model of ERK-mediated somitogenesis, in which bistable ERK activity is regulated by an FGF gradient, cell-cell communication, and the segmentation clock, subject to the intrinsic noise. The model simulation generated our previous in vivo observation that the ERK activity was distributed in a step-like gradient in the presomitic mesoderm, and its boundary was posteriorly shifted by the clock in a stepwise manner, leading to regular somite formation. Here, we showed that this somite regularity was robustly maintained against the noise. Removing the clock from the model predicted that the stepwise shift of the ERK activity occurs at irregular timing with irregular distance owing to the noise, resulting in somite size variation. This model prediction was recently confirmed by live imaging of ERK activity in zebrafish embryos. Through theoretical analysis, we presented a mechanism by which the clock reduces the inherent somite irregularity observed in clock-deficient embryos. Therefore, this study indicates a novel role of the segmentation clock in noise-resistant developmental reproducibility.
Induction of Mesoderm and Neural Crest-Derived Pericytes from Human Pluripotent Stem Cells to Study Blood-Brain Barrier Interactions.
Feb 12, 2019   Stem Cell Reports
Faal T, Phan DTT, Davtyan H, Scarfone VM, Varady E, Blurton-Jones M, Hughes CCW, Inlay MA
Induction of Mesoderm and Neural Crest-Derived Pericytes from Human Pluripotent Stem Cells to Study Blood-Brain Barrier Interactions.
Feb 12, 2019
Stem Cell Reports
In the CNS, perivascular cells ("pericytes") associate with endothelial cells to mediate the formation of tight junctions essential to the function of the blood-brain barrier (BBB). The BBB protects the CNS by regulating the flow of nutrients and toxins into and out of the brain. BBB dysfunction has been implicated in the progression of Alzheimer's disease (AD), but the role of pericytes in BBB dysfunction in AD is not well understood. In the developing embryo, CNS pericytes originate from two sources: mesoderm and neural crest. In this study, we report two protocols using mesoderm or neural crest intermediates, to generate brain-specific pericyte-like cells from induced pluripotent stem cell (iPSC) lines created from healthy and AD patients. iPSC-derived pericytes display stable expression of pericyte surface markers and brain-specific genes and are functionally capable of increasing vascular tube formation and endothelial barrier properties.
Machine Learning of Stem Cell Identities From Single-Cell Expression Data via Regulatory Network Archetypes.
Feb 08, 2019   Frontiers In Genetics
Stumpf PS, MacArthur BD
Machine Learning of Stem Cell Identities From Single-Cell Expression Data via Regulatory Network Archetypes.
Feb 08, 2019
Frontiers In Genetics
The molecular regulatory network underlying stem cell pluripotency has been intensively studied, and we now have a reliable ensemble model for the "average" pluripotent cell. However, evidence of significant cell-to-cell variability suggests that the activity of this network varies within individual stem cells, leading to differential processing of environmental signals and variability in cell fates. Here, we adapt a method originally designed for face recognition to infer regulatory network patterns within individual cells from single-cell expression data. Using this method we identify three distinct network configurations in cultured mouse embryonic stem cells-corresponding to naïve and formative pluripotent states and an early primitive endoderm state-and associate these configurations with particular combinations of regulatory network activity archetypes that govern different aspects of the cell's response to environmental stimuli, cell cycle status and core information processing circuitry. These results show how variability in cell identities arise naturally from alterations in underlying regulatory network dynamics and demonstrate how methods from machine learning may be used to better understand single cell biology, and the collective dynamics of cell communities.
Rapid Differentiation of Multi-Zone Ocular Cells from Human Induced Pluripotent Stem Cells and Generation of Corneal Epithelial and Endothelial Cells.
Feb 04, 2019   Stem Cells And Development
Li Z, Duan H, Li W, Hu X, Jia Y, Zhao C, Zhang S, Zhou Q, Shi W
Rapid Differentiation of Multi-Zone Ocular Cells from Human Induced Pluripotent Stem Cells and Generation of Corneal Epithelial and Endothelial Cells.
Feb 04, 2019
Stem Cells And Development
Eye is a complex organ with highly specialized tissue structure. The establishment of human pluripotent stem cells (hPSCs) has allowed the simulation of eye development in vitro. Most differentiation works of hPSC-derived ocular cells focus on a single, tissue-specific lineage, however, which face the difficulty in reflecting the complexity of eye development. Recently, generation of a self-formed ectodermal automomous multi-zone of ocular cells availably mimics the process of whole-eye development. In this study, we developed a rapid defined method to induce the differentiation of multi-zone ocular cells (MZOCs) from human induced pluripotent stem cells, which specifically experienced the key progenitor stages of anterior neuroectoderm and eye field stem cells by 2.5-dimensional culture. These differentiated cell types spanned neural retina, retinal pigment epithelium, surface ectoderm, neural crest and lens cells. In addition, the surface ectoderm zone of MZOCs could be mechanically isolated and induced into corneal epithelial cells, and the isolated neural crest zone could be directed into corneal endothelial cells. This in vitro differentiation process vividly mimics the development of vertebrate eye, and provides a promising model for the study of ocular morphogenesis, as well as an ideal resource of seed cells for corneal regenerative medicine.
Peli1b governs the brain patterning via ERK signaling pathways in zebrafish embryos.
Feb 15, 2019   Gene
Kumar A, Anuppalle M, Maddirevula S, Huh TL, Choe J, Rhee M
Peli1b governs the brain patterning via ERK signaling pathways in zebrafish embryos.
Feb 15, 2019
Gene
Pellino proteins are associated with immune and stress responses through their effects on NF-κB signaling and B-cell development, and through their role as a scaffold in TLR/IL-1R signaling pathways. However, their function during embryonic development is unclear. Here, we report the developmental expression patterns and functions of peli1b, which encodes a zebrafish ortholog of human Pellino1. Maternal peli1b transcripts were present in zebrafish embryos at the 1-cell stage and zygotic transcripts appeared in the shield area at 6 hours post fertilization (hpf), particularly in the neural plate of the dorsal region. peli1b transcripts were concentrated in the somites, lens, myogenic cells, lateral plate mesoderm, and presomitic mesoderm at 12 hpf, but expression shifted to the telencephalon, diencephalon, hindbrain, and rhombomeres (r1-7) at 24 hpf. Distribution of peli1b transcripts was further restricted to the telencephalon, diencephalon, hindbrain, eyes, and pectoral fins at 48 hpf. Knock-down of peli1b with a peli1b antisense morpholino resulted in significant developmental defects and a reduction in size of the telencephalon, diencephalon, rhombomeres (r1-7), and spinal cord at 24 hpf. When peli1b-knock-down embryos were analyzed for zic3, a marker associated with the central nervous system, we found lower levels of zic3 transcripts in the shield area at 6 hpf and in the posterior diencephalon, dorsal neural plate, midbrain, and hindbrain at 14 hpf. Finally, the ERK3/4 inhibitor SB203580 also induced a significant reduction in the level of zic3 transcripts in the neural plate at 6 hpf and in the posterior diencephalon, dorsal neural plate, midbrain, hindbrain, segmental plate, dorsal spinal cord, and dorsal posterior neural plate at 14 hpf. It is thus likely that the association between Peli1b and brain development in zebrafish embryos occurs via ERK3/4 pathways.
Defining early hematopoietic-fated primitive streak specification of human pluripotent stem cells by the orchestrated balance of Wnt, activin, and BMP signaling.
Feb 16, 2019   Journal Of Cellular Physiology
Shen J, Lyu C, Zhu Y, Feng Z, Zhang S, Hoyle DL, Ji G, Brodsky RA, Cheng T, Wang ZZ
Defining early hematopoietic-fated primitive streak specification of human pluripotent stem cells by the orchestrated balance of Wnt, activin, and BMP signaling.
Feb 16, 2019
Journal Of Cellular Physiology
Distinct regions of the primitive streak (PS) have diverse potential to differentiate into several tissues, including the hematopoietic lineage originated from the posterior region of PS. Although various signaling pathways have been identified to promote the development of PS and its mesoderm derivatives, there is a large gap in our understanding of signaling pathways that regulate the hematopoietic fate of PS. Here, we defined the roles of Wnt, activin, and bone morphogenetic protein (BMP) signaling pathways in generating hematopoietic-fated PS from human pluripotent stem cells (hPSCs). We found that the synergistic balance of these signaling pathways was crucial for controlling the PS fate determination towards hematopoietic lineage via mesodermal progenitors. Although the induction of PS depends largely on the Wnt and activin signaling, the PS generated without BMP4 lacks the hematopoietic potential, indicating that the BMP signaling is necessary for the PS to acquire hematopoietic property. Appropriate levels of Wnt signaling is crucial for the development of PS and its specification to the hematopoietic lineage. Although the development of PS is less sensitive to activin or BMP signaling, the fate of PS to mesoderm progenitors and subsequent hematopoietic lineage is determined by appropriate levels of activin or BMP signaling. Collectively, our study demonstrates that Wnt, activin, and BMP signaling pathways play cooperative and distinct roles in regulating the fate determination of PS for hematopoietic development. Our understanding of the regulatory networks of hematopoietic-fated PS would provide important insights into early hematopoietic patterning and possible guidance for generating functional hematopoietic cells from hPSCs in vitro.
Edar is a downstream target of beta-catenin and drives collagen accumulation in the mouse prostate.
Feb 16, 2019   Biology Open
Wegner KA, Mehta V, Johansson JA, Mueller BR, Keil KP, Abler LL, Marker PC, Taketo MM, Headon DJ, Vezina CM
Edar is a downstream target of beta-catenin and drives collagen accumulation in the mouse prostate.
Feb 16, 2019
Biology Open
Beta-catenin (CTNNB1) directs ectodermal appendage spacing by activating ectodysplasin A receptor (EDAR) transcription but whether CTNNB1 acts by a similar mechanism in prostate, an endoderm-derived tissue, is unclear. Here we examined the expression, function, and CTNNB1 dependence of the EDAR pathway during prostate development. In situ hybridization studies reveal EDAR pathway components including Wnt10b in developing prostate and localize these factors to prostatic bud epithelium where CTNNB1 target genes are co-expressed. We used a genetic approach to ectopically activate CTNNB1 in developing mouse prostate and observed focal increases in Edar and Wnt10b mRNAs. We also used a genetic approach to test the prostatic consequences of activating or inhibiting Edar expression. Edar overexpression does not visibly alter prostatic bud formation or branching morphogenesis, and Edar expression is not necessary for either of these events. However, Edar overexpression is associated with an abnormally thick and collagen-rich stroma in adult mouse prostate. These results support CTNNB1 as a transcriptional activator of Edar and Wnt10b in developing prostate and demonstrate Edar is not only important for ectodermal appendage patterning but also influences collagen organization in adult prostate.
Bioinformatic analysis of next‑generation sequencing data to identify dysregulated genes in fibroblasts of idiopathic pulmonary fibrosis.
Feb 05, 2019   International Journal Of Molecular Medicine
Sheu CC, Chang WA, Tsai MJ, Liao SH, Chong IW, Kuo PL
Bioinformatic analysis of next‑generation sequencing data to identify dysregulated genes in fibroblasts of idiopathic pulmonary fibrosis.
Feb 05, 2019
International Journal Of Molecular Medicine
Idiopathic pulmonary fibrosis (IPF) is a lethal fibrotic lung disease with an increasing global burden. It is hypothesized that fibroblasts have a number of functions that may affect the development and progression of IPF. However, the present understanding of cellular and molecular mechanisms associated with fibroblasts in IPF remains limited. The present study aimed to identify the dysregulated genes in IPF fibroblasts, elucidate their functions and explore potential microRNA (miRNA)‑mRNA interactions. mRNA and miRNA expression profiles were obtained from IPF fibroblasts and normal lung fibroblasts using a next‑generation sequencing platform, and bioinformatic analyses were performed in a step‑wise manner. A total of 42 dysregulated genes (>2 fold‑change of expression) were identified, of which 5 were verified in the Gene Expression Omnibus (GEO) database analysis, including the upregulation of neurotrimin (NTM), paired box 8 (PAX8) and mesoderm development LRP chaperone, and the downregulation of ITPR interacting domain containing 2 and Inka box actin regulator 2 (INKA2). Previous data indicated that PAX8 and INKA2 serve roles in cell growth, proliferation and survival. Gene Ontology analysis indicated that the most significant function of these 42 dysregulated genes was associated with the composition and function of the extracellular matrix (ECM). A total of 60 dysregulated miRNAs were also identified, and 1,908 targets were predicted by the miRmap database. The integrated analysis of mRNA and miRNA expression data, combined with GEO verification, finally identified Homo sapiens (hsa)‑miR‑1254‑INKA2 and hsa‑miR‑766‑3p‑INKA2 as the potential miRNA‑mRNA interactions in IPF fibroblasts. In summary, the results of the present study suggest that dysregulation of PAX8, hsa‑miR‑1254‑INKA2 and hsa‑miR‑766‑3p‑INKA2 may promote the proliferation and survival of IPF fibroblasts. In the functional analysis of the dysregulated genes, a marked association between fibroblasts and the ECM was identified. These data improve the current understanding of fibroblasts as key cells in the pathogenesis of IPF. As a screening study using bioinformatics approaches, the results of the present study require additional validation.
Distinct dormancy progression depending on embryonic regions during mouse embryonic diapause.
Feb 04, 2019   Biology Of Reproduction
Kamemizu C, Fujimori T
Distinct dormancy progression depending on embryonic regions during mouse embryonic diapause.
Feb 04, 2019
Biology Of Reproduction
Many mammalian species undergo embryonic diapause and suspend development at the blastocyst stage before implantation, which is also known as delayed implantation. We studied the process of how mouse embryos enter a dormancy status at a cellular level. Immunofluorescent analysis of differentiation markers for epiblast, primitive endoderm and trophectoderm suggested that cell differentiation status was maintained during 7days in diapause. To understand the progression of cellular dormancy during diapause, we examined the expression of a transgenic cell cycle marker Fucci2 and Ki67 by antibody staining, in addition to direct counting of nuclei in embryos. From these analyses, embryos during diapause were categorized into four stages by cell number and cell cycle. Cell cycle arrest occurred from the ab-embryonic region, and from the TE to the ICM in the embryonic side. We also observed cell cycle transition by live imaging of Fucci2 embryos during the reactivation in culture from dormant status. Cell cycle was initially recovered from the embryonic side of embryos and eventually spread throughout the whole embryo. We also found that embryos in later stages of diapause required a longer period of time for reactivation. From these observations, it was shown that entrance into and exit from dormant status varied depending on cell types and location of cells in an embryo. These results suggest that embryonic diapause includes multiple steps and the mechanisms involved in cellular dormancy may be distinct between embryonic regions.
Sequence Variants in TBX6 Are Associated with Disorders of the Müllerian Ducts: An Update.
Feb 10, 2019   Sexual Development : Genetics, Molecular Biology, Evolution, Endocrinology, Embryology, And Pathology Of Sex Determination And Differentiation
Tewes AC, Hucke J, Römer T, Kapczuk K, Schippert C, Hillemanns P, Wieacker P, Ledig S
Sequence Variants in TBX6 Are Associated with Disorders of the Müllerian Ducts: An Update.
Feb 10, 2019
Sexual Development : Genetics, Molecular Biology, Evolution, Endocrinology, Embryology, And Pathology Of Sex Determination And Differentiation
Müllerian anomalies comprise the Mayer-Rokitansky-Küster-Hauser syndrome as well as fusion defects of the müllerian ducts. Recurrent micro-aberrations like deletions in 16p11.2 encompassing TBX6 were found to be causative in these patients. TBX6 encodes a transcription factor which plays a role in paraxial mesoderm differentiation/specification. In previous studies, we and other groups found possibly pathogenic variants in TBX6 in patients with müllerian anomalies. Since we suggested TBX6 as a strong candidate, we performed sequential analysis of the TBX6 gene in additional 125 patients with müllerian anomalies, and 2 possibly pathogenic missense variants and 1 nonsense substitution in TBX6 in 4/125 patients were found. The missense variant c.484G>A, which we have described in a previous study, was reidentified but with no higher frequency as in our controls. We detected 3 possibly pathogenic variants in TBX6 and could show that the variant c.484G>A is not causative for disorders of the müllerian ducts in the non-Finnish European population. In summary, we present increasing evidence for association of variants in TBX6 with malformations of the müllerian ducts.
Influence of hormones on osteogenic differentiation processes of mesenchymal stem cells.
Feb 12, 2019   Expert Review Of Endocrinology & Metabolism
Ebert R, Schütze N, Schilling T, Seefried L, Weber M, Nöth U, Eulert J, Jakob F
Influence of hormones on osteogenic differentiation processes of mesenchymal stem cells.
Feb 12, 2019
Expert Review Of Endocrinology & Metabolism
Bone development, regeneration and maintenance are governed by osteogenic differentiation processes from mesenchymal stem cells through to mature bone cells, which are directed by local growth and differentiation factors and modulated strongly by hormones. Mesenchymal stem cells develop from both mesoderm and neural crest and can give rise to development, regeneration and maintenance of mesenchymal tissues, such as bone, cartilage, muscle, tendons and discs. There are only limited data regarding the effects of hormones on early events, such as regulation of stemness and maintenance of the mesenchymal stem cell pool. Hormones, such as estrogens, vitamin D-hormone and parathyroid hormone, besides others, are important modulators of osteogenic differentiation processes and bone formation, starting off with fate decision and the development of osteogenic offspring from mesenchymal stem cells, which end up in osteoblasts and osteocytes. Hormones are involved in fetal bone development and regeneration and, in childhood, adolescence and adulthood, they control adaptive needs for growth and reproduction, nutrition, physical power and crisis adaptation. As in other tissues, aging in mesenchymal stem cells and their osteogenic offspring is accompanied by the accumulation of genomic and proteomic damage caused by oxidative burden and insufficient repair. Failsafe programs, such as apoptosis and cellular senescence avoid tumorigenesis. Hormones can influence the pace of such events, thus supporting the quality of tissue regeneration in aging organisms in vivo; for example, by delaying osteoporosis development. The potential for hormones in systemic therapeutic strategies is well appreciated and some concepts are approved for clinical use already. Their potential for cell-based therapeutic strategies for tissue regeneration is probably underestimated and could enhance the quality of tissue-engineering constructs for transplantation and the concept of in situ-guided tissue regeneration.

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