scholarly journals Regulation of neurogenesis and gliogenesis by the matricellular protein CCN2 in the mouse retina

2021 ◽  
Author(s):  
Golam Mohiuddin ◽  
Genesis Lopez ◽  
Jose Sinon ◽  
M. Elizabeth Hartnett ◽  
Anastasiia Bulakhova ◽  
...  
Keyword(s):  
Glial Cell ◽  
Cell Fate ◽  
Matrix Protein ◽  
Ex Vivo ◽  
Mouse Genetics ◽  
Extracellular Matrix Protein ◽  
Retinal Cell ◽  
Mouse Retina ◽  
Matricellular Protein ◽  
Retinal Progenitor

AbstractCellular communication network (CCN) 2 is an extracellular matrix protein with cell type- and context-dependent functions. Using a combination of mouse genetics and omic approaches, we show that CCN2 is expressed in early embryonic retinal progenitor cells (RPCs) and becomes restricted to fully differentiated Müller glial cells (MGCs) thereafter. Germline deletion of CCN2 in mice decreases BrdU labeling, reduces RPC pool, and impairs the competency of remaining RPCs to generate early and late born retinal cell types. Retinal hypocellularity and microphthalmia ensue. The transcriptomic changes associated with CCN2 inactivation include reduced marker and transcriptional regulator genes of retinal ganglion cells, photoreceptors and MGCs. Yap (Yes-associated protein), a singular node for transcriptional regulation of growth and differentiation genes, is also a target of CCN2 signals. In an organotypic model of ex vivo cultured embryonic retinas, CCN2 and YAP immunoreactivity signals overlap. Lentivirus-mediated YAP expression in CCN2-deficient retinal explants increases the number of differentiating Sox9-positive MGCs. Taken together, our data indicate that CCN2 controls the proliferative and differentiation potentials of RPCs ultimately endowing, a subpopulation thereof, with Müller glial cell fate.Summary statementA CCN2-YAP regulatory axis controls retinal progenitor cell growth and lineage commitment to neuronal and glial cell fates.

scholarly journals Cdc42 and formin activity control non-muscle myosin dynamics during Drosophila heart morphogenesis

2014 ◽  
Vol 206 (7) ◽  
pp. 909-922 ◽  
Author(s):  
Georg Vogler ◽  
Jiandong Liu ◽  
Timothy W. Iafe ◽  
Ede Migh ◽  
József Mihály ◽  
...  
Keyword(s):  
Cell Fate ◽  
Matrix Protein ◽  
Small Gtpase ◽  
Extracellular Matrix Protein ◽  
Specific Expression ◽  
Heart Morphogenesis ◽  
Lumen Formation ◽  
Spatiotemporal Regulation ◽  
Genetic Mechanisms ◽  
Heart Formation

During heart formation, a network of transcription factors and signaling pathways guide cardiac cell fate and differentiation, but the genetic mechanisms orchestrating heart assembly and lumen formation remain unclear. Here, we show that the small GTPase Cdc42 is essential for Drosophila melanogaster heart morphogenesis and lumen formation. Cdc42 genetically interacts with the cardiogenic transcription factor tinman; with dDAAM which belongs to the family of actin organizing formins; and with zipper, which encodes nonmuscle myosin II. Zipper is required for heart lumen formation, and its spatiotemporal activity at the prospective luminal surface is controlled by Cdc42. Heart-specific expression of activated Cdc42, or the regulatory formins dDAAM and Diaphanous caused mislocalization of Zipper and induced ectopic heart lumina, as characterized by luminal markers such as the extracellular matrix protein Slit. Placement of Slit at the lumen surface depends on Cdc42 and formin function. Thus, Cdc42 and formins play pivotal roles in heart lumen formation through the spatiotemporal regulation of the actomyosin network.

scholarly journals Integrin-αvβ3 regulates thrombopoietin-mediated maintenance of hematopoietic stem cells

Blood ◽  
2012 ◽  
Vol 119 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Terumasa Umemoto ◽  
Masayuki Yamato ◽  
Jun Ishihara ◽  
Yoshiko Shiratsuchi ◽  
Mika Utsumi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Matrix Protein ◽  
Ex Vivo ◽  
Extracellular Matrix Protein ◽  
Αvβ3 Integrin ◽  
Hematopoietic Stem ◽  
Β3 Integrin ◽  
Ex Vivo Culture

AbstractThroughout life, one's blood supply depends on sustained division of hematopoietic stem cells (HSCs) for self-renewal and differentiation. Within the bone marrow microenvironment, an adhesion-dependent or -independent niche system regulates HSC function. Here we show that a novel adhesion-dependent mechanism via integrin-β3 signaling contributes to HSC maintenance. Specific ligation of β3-integrin on HSCs using an antibody or extracellular matrix protein prevented loss of long-term repopulating (LTR) activity during ex vivo culture. The actions required activation of αvβ3-integrin “inside-out” signaling, which is dependent on thrombopoietin (TPO), an essential cytokine for activation of dormant HSCs. Subsequent “outside-in” signaling via phosphorylation of Tyr747 in the β3-subunit cytoplasmic domain was indispensable for TPO-dependent, but not stem cell factor-dependent, LTR activity in HSCs in vivo. This was accompanied with enhanced expression of Vps72, Mll1, and Runx1, 3 factors known to be critical for maintaining HSC activity. Thus, our findings demonstrate a mechanistic link between β3-integrin and TPO in HSCs, which may contribute to maintenance of LTR activity in vivo as well as during ex vivo culture.

scholarly journals Generation, transcriptome profiling, and functional validation of cone-rich human retinal organoids

2019 ◽  
Vol 116 (22) ◽  
pp. 10824-10833 ◽  
Author(s):  
Sangbae Kim ◽  
Albert Lowe ◽  
Rachayata Dharmat ◽  
Seunghoon Lee ◽  
Leah A. Owen ◽  
...  
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Cell Fate ◽  
Time Course ◽  
Transcriptome Profiling ◽  
Retinal Cell ◽  
Peripheral Retina ◽  
Functional Validation ◽  
Retinal Progenitor ◽  
Retinal Differentiation

Rod and cone photoreceptors are light-sensing cells in the human retina. Rods are dominant in the peripheral retina, whereas cones are enriched in the macula, which is responsible for central vision and visual acuity. Macular degenerations affect vision the most and are currently incurable. Here we report the generation, transcriptome profiling, and functional validation of cone-rich human retinal organoids differentiated from hESCs using an improved retinal differentiation system. Induced by extracellular matrix, aggregates of hESCs formed single-lumen cysts composed of epithelial cells with anterior neuroectodermal/ectodermal fates, including retinal cell fate. Then, the cysts were en bloc-passaged, attached to culture surface, and grew, forming colonies in which retinal progenitor cell patches were found. Following gentle cell detachment, retinal progenitor cells self-assembled into retinal epithelium—retinal organoid—that differentiated into stratified cone-rich retinal tissue in agitated cultures. Electron microscopy revealed differentiating outer segments of photoreceptor cells. Bulk RNA-sequencing profiling of time-course retinal organoids demonstrated that retinal differentiation in vitro recapitulated in vivo retinogenesis in temporal expression of cell differentiation markers and retinal disease genes, as well as in mRNA alternative splicing. Single-cell RNA-sequencing profiling of 8-mo retinal organoids identified cone and rod cell clusters and confirmed the cone enrichment initially revealed by quantitative microscopy. Notably, cones from retinal organoids and human macula had similar single-cell transcriptomes, and so did rods. Cones in retinal organoids exhibited electrophysiological functions. Collectively, we have established cone-rich retinal organoids and a reference of transcriptomes that are valuable resources for retinal studies.

scholarly journals Extracellular SPARC improves cardiomyocyte contraction during health and disease

2018 ◽  
Author(s):  
Sophie Deckx ◽  
Daniel M. Johnson ◽  
Marieke Rienks ◽  
Paolo Carai ◽  
Elza van Deel ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Matrix Protein ◽  
Contractile Function ◽  
Ex Vivo ◽  
Cardiac Fibroblasts ◽  
Cardiac Injury ◽  
Coxsackie Virus ◽  
Extracellular Matrix Protein

Secreted protein acidic and rich in cysteine (SPARC) is a non-structural extracellular matrix protein that regulates interactions between the matrix and neighboring cells. In the cardiovascular system, it is expressed by cardiac fibroblasts, endothelial cells, and in lower levels by ventricular cardiomyocytes. SPARC expression levels are increased upon myocardial injury and also during hypertrophy and fibrosis. We have previously shown that SPARC improves cardiac function after myocardial infarction by regulating post-synthetic procollagen processing, however whether SPARC directly affects cardiomyocyte contraction is still unknown. In this study we demonstrate a novel inotropic function for extracellular SPARC in the healthy heart as well as in the diseased state after myocarditis-induced cardiac dysfunction. We demonstrate SPARC presence on the cardiomyocyte membrane where it is co-localized with the integrin-beta1 and the integrin-linked kinase. Moreover, extracellular SPARC directly improves cardiomyocyte cell shortening ex vivo and cardiac function in vivo, both in healthy myocardium and during coxsackie virus-induced cardiac dysfunction. In conclusion, we demonstrate a novel inotropic function for SPARC in the heart, with a potential therapeutic application when myocyte contractile function is diminished such as that caused by a myocarditis-related cardiac injury.

scholarly journals Loss of the Extracellular Matrix Protein DIG-1 Causes Glial Fragmentation, Dendrite Breakage and Dendrite Extension Defects

2021 ◽  
Vol 9 (4) ◽  
pp. 42
Author(s):  
Megan K. Chong ◽  
Elizabeth R. Cebul ◽  
Karolina Mizeracka ◽  
Maxwell G. Heiman
Keyword(s):  
Extracellular Matrix ◽  
Nervous System ◽  
Young Adults ◽  
Glial Cell ◽  
Sensory Neurons ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
C Elegans ◽  
Cellular Integrity ◽  
Novel Alleles

The extracellular matrix (ECM) guides and constrains the shape of the nervous system. In C. elegans, DIG-1 is a giant ECM component that is required for fasciculation of sensory dendrites during development and for maintenance of axon positions throughout life. We identified four novel alleles of dig-1 in three independent screens for mutants affecting disparate aspects of neuronal and glial morphogenesis. First, we find that disruption of DIG-1 causes fragmentation of the amphid sheath glial cell in larvae and young adults. Second, it causes severing of the BAG sensory dendrite from its terminus at the nose tip, apparently due to breakage of the dendrite as animals reach adulthood. Third, it causes embryonic defects in dendrite fasciculation in inner labial (IL2) sensory neurons, as previously reported, as well as rare defects in IL2 dendrite extension that are enhanced by loss of the apical ECM component DYF-7, suggesting that apical and basolateral ECM contribute separately to dendrite extension. Our results highlight novel roles for DIG-1 in maintaining the cellular integrity of neurons and glia, possibly by creating a barrier between structures in the nervous system.

scholarly journals Phenotypic analysis of c-Kit expression in epithelial monolayers derived from postnatal rat pancreatic islets

2004 ◽  
Vol 182 (1) ◽  
pp. 113-122 ◽  
Author(s):  
R Wang ◽  
J Li ◽  
N Yashpal
Keyword(s):  
Stem Cell ◽  
Progenitor Cells ◽  
Matrix Protein ◽  
Ex Vivo ◽  
Stem Cell Marker ◽  
Haematopoietic Stem Cell ◽  
Extracellular Matrix Protein ◽  
Type I ◽  
Cytokeratin 20 ◽  
Epithelial Monolayers

The limitation of available islets for transplantation is a major obstacle for the treatment of diabetes through islet therapy. However, islet monolayers expanded ex vivo may provide a source of progenitor cells and a model to help understand islet development from precursor cell types. The existence of progenitor cells within the islets is highly likely, yet, to date, no fully defined or characterized postnatal stem cell has been isolated, expanded or marked. Our study evaluates the expression of progenitor markers, including the haematopoietic stem cell marker c-Kit, in epithelial monolayers derived from postnatal rat islets through immunofluorescence and RT-PCR, and the ability of precursor-rich monolayers to reform islet-like structures. Islets formed confluent monolayers when cultured on a type I collagen gel which lacked endocrine phenotypes but were positive for cytokeratin 20 and contained an increased proportion of proliferating c-Kit-expressing cells, with the proportion reaching a maximum of 45+/-6% at 8 weeks of culture. Evaluation of transcription factors at the mRNA level revealed constant PDX-1, ngn3 and Pax4 expression, while undifferentiated cell markers, such as Oct4 and alpha-fetoprotein, were also detected frequently after 4 weeks of culture. Changing the extracellular matrix protein to laminin-rich Matrigel, the monolayers re-formed islet-like clusters that secreted insulin in a glucose-responsive fashion. Our data show that islets can be expanded ex vivo to form epithelial monolayers with rich undifferentiating cell populations that are characterized by cells expressing the progenitor markers. These monolayers are capable of extensive proliferation and retain plasticity to form new islet cells, and c-Kit-expressing cells may play an important role in new islet cluster formation.

scholarly journals Endorepellin evokes an angiostatic stress signaling cascade in endothelial cells

2020 ◽  
Vol 295 (19) ◽  
pp. 6344-6356 ◽  
Author(s):  
Aastha Kapoor ◽  
Carolyn G. Chen ◽  
Renato V. Iozzo
Keyword(s):  
Endothelial Cells ◽  
Matrix Protein ◽  
Ex Vivo ◽  
Effector Proteins ◽  
Extracellular Matrix Protein ◽  
Signaling Cascade ◽  
Stress Signaling ◽  
Downstream Effector ◽  
Transient Activation ◽  
Phosphorylated Eif2α

Endorepellin, the C-terminal fragment of the heparan sulfate proteoglycan perlecan, influences various signaling pathways in endothelial cells by binding to VEGFR2. In this study, we discovered that soluble endorepellin activates the canonical stress signaling pathway consisting of PERK, eIF2α, ATF4, and GADD45α. Specifically, endorepellin evoked transient activation of VEGFR2, which, in turn, phosphorylated PERK at Thr980. Subsequently, PERK phosphorylated eIF2α at Ser51, upregulating its downstream effector proteins ATF4 and GADD45α. RNAi-mediated knockdown of PERK or eIF2α abrogated the endorepellin-mediated up-regulation of GADD45α, the ultimate effector protein of this stress signaling cascade. To functionally validate these findings, we utilized an ex vivo model of angiogenesis. Exposure of the aortic rings embedded in 3D fibrillar collagen to recombinant endorepellin for 2–4 h activated PERK and induced GADD45α vis à vis vehicle-treated counterparts. Similar effects were obtained with the established cellular stress inducer tunicamycin. Notably, chronic exposure of aortic rings to endorepellin for 7–9 days markedly suppressed vessel sprouting, an angiostatic effect that was rescued by blocking PERK kinase activity. Our findings unravel a mechanism by which an extracellular matrix protein evokes stress signaling in endothelial cells, which leads to angiostasis.

scholarly journals Loss of the extracellular matrix protein DIG-1 causes glial fragmentation, dendrite breakage, and dendrite extension defects

2021 ◽  
Author(s):  
Megan K Chong ◽  
Elizabeth R Cebul ◽  
Karolina Mizeracka ◽  
Maxwell G Heiman
Keyword(s):  
Extracellular Matrix ◽  
Nervous System ◽  
Young Adults ◽  
Glial Cell ◽  
Sensory Neurons ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
C Elegans ◽  
Cellular Integrity ◽  
Novel Alleles

The extracellular matrix (ECM) guides and constrains the shape of the nervous system. In C. elegans, DIG-1 is a giant ECM component that is required for fasciculation of sensory dendrites during development and for maintenance of axon positions throughout life. We identified four novel alleles of dig-1 in three independent screens for mutants affecting disparate aspects of neuronal and glial morphogenesis. First, we find that disruption of DIG-1 causes fragmentation of the amphid sheath glial cell in larvae and young adults. Second, it causes severing of the BAG sensory dendrite from its terminus at the nose tip, apparently due to breakage of the dendrite as animals reach adulthood. Third, it causes embryonic defects in dendrite fasciculation in inner labial (IL2) sensory neurons, as previously reported, as well as rare defects in IL2 dendrite extension that are enhanced by loss of the apical ECM component DYF-7, suggesting that apical and basolateral ECM contribute separately to dendrite extension. Our results highlight novel roles for DIG-1 in maintaining the cellular integrity of neurons and glia, possibly by creating a barrier between structures in the nervous system.

scholarly journals A CTGF-YAP regulatory pathway is essential for angiogenesis and barriergenesis in the retina

2020 ◽  
Author(s):  
Sohyun Moon ◽  
Sangmi Lee ◽  
JoyAnn Caesar ◽  
Sarah Pruchenko ◽  
Andew Leask ◽  
...  
Keyword(s):  
Growth Factor ◽  
Matrix Protein ◽  
Vascular Development ◽  
Tissue Growth ◽  
Molecular Signature ◽  
Extracellular Matrix Protein ◽  
Matricellular Protein ◽  
Permeability Barrier ◽  
Barrier Breakdown ◽  
Regulator Genes

ABSTRACTConnective tissue growth factor (CTGF) or CCN2 is a matricellular protein essential for normal embryonic development and tissue repair. CTGF exhibits cell- and context-dependent activities, but the CTGF function in vascular development and permeability barrier is not known. Here we show that endothelial cells (ECs) are one of the major cellular sources of CTGF in the developing and adult retinal vasculature. Mice lacking CTGF expression either globally or specifically in ECs exhibit impaired vascular cell growth and morphogenesis, and blood barrier breakdown. The global molecular signature of CTGF includes cytoskeletal and extracellular matrix protein, growth factor, and transcriptional co-regulator genes such as yes-associated protein (YAP). YAP, itself a transcriptional activator of the CTGF gene, mediates several CTGF-controlled angiogenic and barriergenic transcriptional programs. Re-expression of YAP rescues, at least partially, angiogenesis and barriergenesis in CTGF mutant mouse retinas. Thus, the CTGF-YAP angiomodulatory pathway is critical for vascular development and barrier function.

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