scholarly journals Regionalized tissue fluidization is required for epithelial gap closure during insect gastrulation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Akanksha Jain ◽  
Vladimir Ulman ◽  
Arghyadip Mukherjee ◽  
Mangal Prakash ◽  
Marina B. Cuenca ◽  
...  
Keyword(s):  
Wound Healing ◽  
Tribolium Castaneum ◽  
Leading Edge ◽  
Dorsal Region ◽  
Extraembryonic Tissue ◽  
Ventral Region ◽  
Local Tissue ◽  
Gap Closure ◽  
Epithelial Sheet

Abstract Many animal embryos pull and close an epithelial sheet around the ellipsoidal egg surface during a gastrulation process known as epiboly. The ovoidal geometry dictates that the epithelial sheet first expands and subsequently compacts. Moreover, the spreading epithelium is mechanically stressed and this stress needs to be released. Here we show that during extraembryonic tissue (serosa) epiboly in the insect Tribolium castaneum, the non-proliferative serosa becomes regionalized into a solid-like dorsal region with larger non-rearranging cells, and a more fluid-like ventral region surrounding the leading edge with smaller cells undergoing intercalations. Our results suggest that a heterogeneous actomyosin cable contributes to the fluidization of the leading edge by driving sequential eviction and intercalation of individual cells away from the serosa margin. Since this developmental solution utilized during epiboly resembles the mechanism of wound healing, we propose actomyosin cable-driven local tissue fluidization as a conserved morphogenetic module for closure of epithelial gaps.

scholarly journals Regionalized tissue fluidization by an actomyosin cable is required for epithelial gap closure during insect gastrulation

2019 ◽  
Author(s):  
A. Jain ◽  
V. Ulman ◽  
A. Mukherjee ◽  
M. Prakash ◽  
L. Pimpale ◽  
...  
Keyword(s):  
Wound Healing ◽  
Tribolium Castaneum ◽  
Leading Edge ◽  
Red Flour Beetle ◽  
Dorsal Region ◽  
Extraembryonic Tissue ◽  
Ventral Region ◽  
Gap Closure ◽  
Epithelial Sheet ◽  
Cell Intercalation

ABSTRACTMany animal embryos pull and close an epithelial sheet around the spherical or ellipsoidal egg surface during a gastrulation process known as epiboly. The ovoidal geometry dictates that the epithelial sheet first expands and subsequently compacts. Moreover, the epithelial sheet spreading over the sphere is mechanically stressed and this stress needs to be released. Here we show that during extraembryonic tissue (serosa) epiboly in the red flour beetle Tribolium castaneum, the non-proliferative serosa becomes regionalized into two distinct territories: a dorsal region under higher tension away from the leading edge with larger non-rearranging cells, and a more fluid ventral region under lower tension surrounding the leading edge with smaller cells undergoing cell intercalation. Our results suggest that fluidization of the leading edge is caused by a heterogeneous actomyosin cable that drives sequential eviction and intercalation of individual cells away from the serosa margin. Since this developmental solution utilized during epiboly resembles the mechanism of wound healing in other systems, we propose actomyosin cable-driven local tissue fluidization as a conserved morphogenetic module for closure of epithelial gaps.

Nanotopography-Modulated Epithelial Cell Collective Migration

2021 ◽  
Vol 17 (6) ◽  
pp. 1079-1087
Author(s):  
Zaozao Chen ◽  
Qiwei Li ◽  
Shihui Xu ◽  
Jun Ouyang ◽  
Hongmei Wei
Keyword(s):  
Wound Healing ◽  
Cell Migration ◽  
Epithelial Cells ◽  
Leading Edge ◽  
Cell Types ◽  
Protein Kinase Activity ◽  
Migration Behavior ◽  
Collective Migration ◽  
Epithelial Migration ◽  
Activity Dependent

Matrix nanotopography plays an essential role in regulating cell behaviors including cell proliferation, differentiation, and migration. While studies on isolated single cell migration along the nanostructural orientation have been reported for various cell types, there remains a lack of understanding of how nanotopography regulates the behavior of collectively migrating cells during processes such as epithelial wound healing. We demonstrated that collective migration of epithelial cells was promoted on nanogratings perpendicular to, but not on those parallel to, the wound-healing axis. We further discovered that nanograting-modulated epithelial migration was dominated by the adhesion turnover process, which was Rho-associated protein kinase activity-dependent, and the lamellipodia protrusion at the cell leading edge, which was Rac1-GTPase activity-dependent. This work provides explanations to the distinct migration behavior of epithelial cells on nanogratings, and indicates that the effect of nanotopographic modulations on cell migration is cell-type dependent and involves complex mechanisms

scholarly journals A genetic variant of cortactin linked to acute lung injury impairs lamellipodia dynamics and endothelial wound healing

2015 ◽  
Vol 309 (9) ◽  
pp. L983-L994 ◽  
Author(s):  
Sangwook Choi ◽  
Sara M. Camp ◽  
Arkaprava Dan ◽  
Joe G. N. Garcia ◽  
Steven M. Dudek ◽  
...  
Keyword(s):  
Wound Healing ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Regulatory Protein ◽  
Actin Binding ◽  
Gap Closure ◽  
Sphingosine 1 Phosphate ◽  
Endothelial Wound Healing ◽  
Genetic Signatures ◽  
The Impact

Inflammatory mediators released in acute lung injury (ALI) trigger the disruption of interendothelial junctions, leading to loss of vascular barrier function, protein-rich pulmonary edema, and severe hypoxemia. Genetic signatures that predict patient recovery or disease progression are poorly defined, but recent genetic screening of ALI patients has identified an association between lung inflammatory disease and a single nucleotide polymorphism (SNP) in the gene for the actin-binding and barrier-regulatory protein cortactin. This study investigated the impact of this disease-linked cortactin variant on wound healing processes that may contribute to endothelial barrier restoration. A microfabricated platform was used to quantify wound healing in terms of gap closure speed, lamellipodia dynamics, and cell velocity. Overexpression of wild-type cortactin in endothelial cells (ECs) improved directional cell motility and enhanced lamellipodial protrusion length, resulting in enhanced gap closure rates. By contrast, the cortactin SNP impaired wound closure and cell locomotion, consistent with the observed reduction in lamellipodial protrusion length and persistence. Overexpression of the cortactin SNP in lung ECs mitigated the barrier-enhancing activity of sphingosine 1-phosphate. These findings suggest that this common cortactin variant may functionally contribute to ALI predisposition by impeding endothelial wound healing.

scholarly journals The Drosophila Shark tyrosine kinase is required for embryonic dorsal closure

2000 ◽  
Vol 14 (5) ◽  
pp. 604-614
Author(s):  
Rafael Fernandez ◽  
Fumitaka Takahashi ◽  
Zhao Liu ◽  
Ruth Steward ◽  
David Stein ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Leading Edge ◽  
Dorsal Closure ◽  
Kinase Gene ◽  
Dorsal Midline ◽  
Jnk Signaling ◽  
Amino Terminal ◽  
Tyrosine Kinase Gene ◽  
Epithelial Sheet ◽  
Jnk Signaling Pathway

Dorsal closure (DC) in the Drosophila embryo requires the coordinated interaction of two different functional domains of the epidermal cell layer—the leading edge (LE) and the lateral epidermis. In response to activation of a conserved c-Jun amino-terminal kinase (JNK) signaling module, the dorsal-most layer of cells, which constitute the LE of the stretching epithelial sheet, secrete Dpp, a member of the TGFβ superfamily. Dpp and other LE cell-derived signaling molecules stimulate the bilateral dorsal elongation of cells of the dorsolateral epidermis over the underlaying amnioserosa and the eventual fusion of their LEs along the dorsal midline. We have found that flies bearing a Shark tyrosine kinase gene mutation,shark1, exhibit a DC-defective phenotype. Dpp fails to be expressed in shark1 mutant LE cells. Consistent with these observations, epidermal-specific reconstitution ofshark function or overexpression of an activated form of c-Jun in the shark1 mutant background, rescues the DC defect. Thus, Shark regulates the JNK signaling pathway leading to Dpp expression in LE cells. Furthermore, constitutive activation of the Dpp pathway throughout the epidermis fails to rescue theshark1 DC defect, suggesting that Shark may function in additional pathways in the LE and/or lateral epithelium.

scholarly journals Epithelial layer unjamming shifts energy metabolism toward glycolysis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephen J. DeCamp ◽  
Victor M. K. Tsuda ◽  
Jacopo Ferruzzi ◽  
Stephan A. Koehler ◽  
John T. Giblin ◽  
...  
Keyword(s):  
Wound Healing ◽  
Energy Metabolism ◽  
Cell Layer ◽  
Healing Process ◽  
Leading Edge ◽  
Cellular Migration ◽  
Wound Healing Process ◽  
Epithelial Layer ◽  
Traction Forces ◽  
Cell Shapes

Abstract In development of an embryo, healing of a wound, or progression of a carcinoma, a requisite event is collective epithelial cellular migration. For example, cells at the advancing front of a wound edge tend to migrate collectively, elongate substantially, and exert tractions more forcefully compared with cells many ranks behind. With regards to energy metabolism, striking spatial gradients have recently been reported in the wounded epithelium, as well as in the tumor, but within the wounded cell layer little is known about the link between mechanical events and underlying energy metabolism. Using the advancing confluent monolayer of MDCKII cells as a model system, here we report at single cell resolution the evolving spatiotemporal fields of cell migration speeds, cell shapes, and traction forces measured simultaneously with fields of multiple indices of cellular energy metabolism. Compared with the epithelial layer that is unwounded, which is non-migratory, solid-like and jammed, the leading edge of the advancing cell layer is shown to become progressively more migratory, fluid-like, and unjammed. In doing so the cytoplasmic redox ratio becomes progressively smaller, the NADH lifetime becomes progressively shorter, and the mitochondrial membrane potential and glucose uptake become progressively larger. These observations indicate that a metabolic shift toward glycolysis accompanies collective cellular migration but show, further, that this shift occurs throughout the cell layer, even in regions where associated changes in cell shapes, traction forces, and migration velocities have yet to penetrate. In characterizing the wound healing process these morphological, mechanical, and metabolic observations, taken on a cell-by-cell basis, comprise the most comprehensive set of biophysical data yet reported. Together, these data suggest the novel hypothesis that the unjammed phase evolved to accommodate fluid-like migratory dynamics during episodes of tissue wound healing, development, and plasticity, but is more energetically expensive compared with the jammed phase, which evolved to maintain a solid-like non-migratory state that is more energetically economical.

The yolk syncytial layer of loach, Misgurnus fossilis (Teleostei) during early development

Zygote ◽  
2017 ◽  
Vol 25 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Ekaterina Kondakova ◽  
Irina Neklyudova ◽  
Vladimir Efremov
Keyword(s):  
Developmental Stages ◽  
Yolk Mass ◽  
Dorsal Region ◽  
Blastula Stage ◽  
Ventral Region ◽  
Basal Surface ◽  
Yolk Syncytial Layer ◽  
Early Developmental ◽  
Different Thickness ◽  
Misgurnus Fossilis

SummaryThe yolk syncytial layer (YSL) of Teleostei is a dynamic multifunctional temporary system. This paper describes the YSL structure of Misgurnus fossilis (Cobitidae) during its early developmental stages, studied using histological methods. YSL formation is prolonged. From the late blastula stage, the basal surface of the YSL is uneven and has protuberances, but becomes smoother during development. There are syncytial ‘islands’ with 1–2 yolk syncytial nuclei in the yolk mass. During epiboly, gastrulation and early segmentation, loach YSL is of different thickness in different regions along the dorso-ventral and antero-posterior axes of an embryo. The YSL is thickened in the dorsal region of gastrulae compared with the ventral region. Although the development of M. fossilis is similar to the development of zebrafish, there are important differences in YSL formation and organization that await further study and analysis. The study of YSL organization contributes to our knowledge of teleost developmental diversity and to the biology of temporary structures.

scholarly journals A role for myosin IXb, a motor–RhoGAP chimera, in epithelial wound healing and tight junction regulation

2012 ◽  
Vol 23 (13) ◽  
pp. 2468-2480 ◽  
Author(s):  
Surjit K. Chandhoke ◽  
Mark S. Mooseker
Keyword(s):  
Wound Healing ◽  
Tight Junction ◽  
Protein Localization ◽  
Leading Edge ◽  
Dominant Negative ◽  
Protein Domain ◽  
Intestinal Barrier Function ◽  
Epithelial Cell Line ◽  
Epithelial Wound Healing ◽  
Tail Tip

Polymorphisms in the gene encoding the heavy chain of myosin IXb (Myo9b) have been linked to several forms of inflammatory bowel disease (IBD). Given that Myo9b contains a RhoGTPase-activating protein domain within its tail, it may play key roles in Rho-mediated actin cytoskeletal modifications critical to intestinal barrier function. In wounded monolayers of the intestinal epithelial cell line Caco2BBe(BBe), Myo9b localizes to the extreme leading edge of lamellipodia of migrating cells. BBe cells exhibiting loss of Myo9b expression with RNA interference or Myo9b C-terminal dominant-negative (DN) tail-tip expression lack lamellipodia, fail to migrate into the wound, and form stress fiber–like arrays of actin at the free edges of cells facing the wound. These cells also exhibit disruption of tight junction (TJ) protein localization, including ZO-1, occludin, and claudin-1. Torsional motility and junctional permeability to dextran are greatly increased in cells expressing DN-tail-tip. Of interest, this effect is propagated to neighboring cells. Consistent with a role for Myo9b in regulating levels of active Rho, localization of both RhoGTP and myosin light chain phosphorylation corresponds to Myo9b-knockdown regions of BBe monolayers. These data reveal critical roles for Myo9b during epithelial wound healing and maintenance of TJ integrity—key functions that may be altered in patients with Myo9b-linked IBD.

scholarly journals Multiple Forces Contribute to Cell Sheet Morphogenesis for Dorsal Closure in Drosophila

2000 ◽  
Vol 149 (2) ◽  
pp. 471-490 ◽  
Author(s):  
Daniel P. Kiehart ◽  
Catherine G. Galbraith ◽  
Kevin A. Edwards ◽  
Wayne L. Rickoll ◽  
Ruth A. Montague
Keyword(s):  
Wound Healing ◽  
Cell Shape ◽  
Cell Sheet ◽  
Leading Edge ◽  
Drosophila Embryo ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Dorsal Closure ◽  
Purse String ◽  
Ultraviolet Laser

The molecular and cellular bases of cell shape change and movement during morphogenesis and wound healing are of intense interest and are only beginning to be understood. Here, we investigate the forces responsible for morphogenesis during dorsal closure with three approaches. First, we use real-time and time-lapsed laser confocal microscopy to follow actin dynamics and document cell shape changes and tissue movements in living, unperturbed embryos. We label cells with a ubiquitously expressed transgene that encodes GFP fused to an autonomously folding actin binding fragment from fly moesin. Second, we use a biomechanical approach to examine the distribution of stiffness/tension during dorsal closure by following the response of the various tissues to cutting by an ultraviolet laser. We tested our previous model (Young, P.E., A.M. Richman, A.S. Ketchum, and D.P. Kiehart. 1993. Genes Dev. 7:29–41) that the leading edge of the lateral epidermis is a contractile purse-string that provides force for dorsal closure. We show that this structure is under tension and behaves as a supracellular purse-string, however, we provide evidence that it alone cannot account for the forces responsible for dorsal closure. In addition, we show that there is isotropic stiffness/tension in the amnioserosa and anisotropic stiffness/tension in the lateral epidermis. Tension in the amnioserosa may contribute force for dorsal closure, but tension in the lateral epidermis opposes it. Third, we examine the role of various tissues in dorsal closure by repeated ablation of cells in the amnioserosa and the leading edge of the lateral epidermis. Our data provide strong evidence that both tissues appear to contribute to normal dorsal closure in living embryos, but surprisingly, neither is absolutely required for dorsal closure. Finally, we establish that the Drosophila epidermis rapidly and reproducibly heals from both mechanical and ultraviolet laser wounds, even those delivered repeatedly. During healing, actin is rapidly recruited to the margins of the wound and a newly formed, supracellular purse-string contracts during wound healing. This result establishes the Drosophila embryo as an excellent system for the investigation of wound healing. Moreover, our observations demonstrate that wound healing in this insect epidermal system parallel wound healing in vertebrate tissues in situ and vertebrate cells in culture (for review see Kiehart, D.P. 1999. Curr. Biol. 9:R602–R605).

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