Regulation of fibroblast migration by tenascin-C

2007 ◽  
Vol 35 (4) ◽  
pp. 695-697 ◽  
Author(s):  
A. Trebaul ◽  
E.K. Chan ◽  
K.S. Midwood
Keyword(s):  
Tissue Repair ◽  
Tissue Injury ◽  
Three Dimensional ◽  
Scar Tissue ◽  
Fibrotic Disease ◽  
Tenascin C ◽  
Fibroblast Migration ◽  
Rate Limiting Step ◽  
Surrounding Healthy Tissue ◽  
Rate Limiting

Synthesis of new tissue by fibroblasts is required for tissue rebuilding in response to injury. Fibroblast migration from surrounding healthy tissue into the fibrin–fibronectin provisional matrix deposited upon injury is a key rate-limiting step of this stage of tissue repair. These events must be tightly regulated. Excessive deposition of scar tissue is the major hallmark of fibrotic disease. Tenascin-C is an extracellular matrix glycoprotein that is transiently expressed upon tissue injury, where it is specifically localized to the wound edge, and persistently up-regulated in fibrotic disease. We have shown that full-length tenascin-C promotes fibroblast migration within fibrin–fibronectin matrices and we have mapped the domains within the molecule critical for enhancing migration. We also demonstrated that specific fragments of tenascin-C inhibit fibroblast migration. These results suggest that transient expression of tenascin-C at the wound boundary is key to tissue repair: its induction recruits fibroblasts into the wound and fragments resulting from its breakdown prevent excessive fibroblast infiltration. Our results demonstrate how fibroblast migration in three-dimensional provisional matrices may be differentially regulated by proteolysis of matrix molecules and could explain how persistent expression of tenascin-C contributes to the progression of fibrotic disease.

An internal enhancer regulates heme- and cadmium-mediated induction of human heme oxygenase-1

2003 ◽  
Vol 285 (3) ◽  
pp. F515-F523 ◽  
Author(s):  
Nathalie Hill-Kapturczak ◽  
Eric Sikorski ◽  
Christy Voakes ◽  
Jairo Garcia ◽  
Harry S. Nick ◽  
...  
Keyword(s):  
Heme Oxygenase ◽  
Tissue Injury ◽  
Molecular Regulation ◽  
Heme Oxygenase 1 ◽  
Aortic Endothelial Cells ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Beneficial Response ◽  
Enhancer Function ◽  
Rate Limiting

Heme oxygenase-1 (HO-1) catalyzes the rate-limiting step in heme degradation, releasing iron, carbon monoxide, and biliverdin. Induction of HO-1 is an adaptive and beneficial response in renal and nonrenal settings of tissue injury. The purpose of this study was to characterize the regulation of the human HO-1 gene in renal proximal tubule and aortic endothelial cells in response to heme and cadmium. Evaluation of multiple human HO-1 promoter-reporter constructs up to -9.1 kb demonstrated only a partial response to heme and cadmium. In an effort to mimic endogenous stimulus-dependent levels of HO-1 induction, we evaluated the entire 12.5 kb of the human HO-1 gene, including introns and exons, in conjunction with a -4.5-kb human HO-1 promoter and observed significant heme- and cadmium-mediated induction of the reporter gene, suggesting the presence of an internal enhancer. Enhancer function was orientation independent and required a region between -3.5 and -4.5 kb of the human HO-1 promoter. Our studies identified a novel enhancer internal to the human HO-1 gene that, in conjunction with the HO-1 promoter, recapitulates heme- and cadmium-mediated induction of the endogenous HO-1 gene. Elucidation of the molecular regulation of the human HO-1 gene will allow for the development of therapeutic strategies to manipulate HO-1 gene expression in pathological states.

Devitrification kinetics and mechanism of Pyrex borosilicate glass

2001 ◽  
Vol 16 (6) ◽  
pp. 1752-1758 ◽  
Author(s):  
Jau-Ho Jean ◽  
Yu-Ching Fang
Keyword(s):  
Borosilicate Glass ◽  
Linear Growth ◽  
Energy Analysis ◽  
Three Dimensional ◽  
Rate Limiting Step ◽  
Dimensional Diffusion ◽  
Limiting Step ◽  
Diffusion Controlled ◽  
Rate Limiting ◽  
Kinetics Of

Cristobalite is formed when initially amorphous Pyrex borosilicate glass (Corning 7740) is fired at temperatures ranging from 700 to 1000 °C. The sigmoidal devitrification kinetics of cristobalite obeys Avrami-like three-dimensional diffusion-controlled kinetics. Activation energy analysis indicates that the diffusion of Na+ in the glass is the rate-limiting step during phase transformation. The above conclusion is further confirmed by calculated and measured results of linear growth rates.

Intrinsic alterations in the hydrogen desorption of Mg2NiH4 by solid dissolution of titanium

2018 ◽  
Vol 47 (25) ◽  
pp. 8418-8426 ◽  
Author(s):  
Pengfei Wei ◽  
Wen Huang ◽  
Xiaoli Ding ◽  
Yongtao Li ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Phase Boundary ◽  
Boundary Migration ◽  
Three Dimensional ◽  
Hydrogen Desorption ◽  
Two Dimensional ◽  
Rate Limiting Step ◽  
Dimensional Diffusion ◽  
Limiting Step ◽  
Rate Limiting

The rate-limiting step for Mg2NiH4 desorption was intrinsically shifted from three-dimensional diffusion to two-dimensional phase boundary migration by titanium dissolution.

scholarly journals Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

2004 ◽  
Vol 15 (12) ◽  
pp. 5670-5677 ◽  
Author(s):  
Kim S. Midwood ◽  
Leyla V. Valenick ◽  
Henry C. Hsia ◽  
Jean E. Schwarzbauer
Keyword(s):  
Extracellular Matrix ◽  
Intracellular Signaling ◽  
Tissue Repair ◽  
Matrix Protein ◽  
Tissue Injury ◽  
Fiber Formation ◽  
Extracellular Matrix Protein ◽  
Actin Stress Fiber ◽  
Tenascin C ◽  
Matrix Contraction

Syndecan-4 is a ubiquitously expressed heparan sulfate proteoglycan that modulates cell interactions with the extracellular matrix. It is transiently up-regulated during tissue repair by cells that mediate wound healing. Here, we report that syndecan-4 is essential for optimal fibroblast response to the three-dimensional fibrin-fibronectin provisional matrix that is deposited upon tissue injury. Interference with syndecan-4 function inhibits matrix contraction by preventing cell spreading, actin stress fiber formation, and activation of focal adhesion kinase and RhoA mediated-intracellular signaling pathways. Tenascin-C is an extracellular matrix protein that regulates cell response to fibronectin within the provisional matrix. Syndecan-4 is also required for tenascin-C action. Inhibition of syndecan-4 function suppresses tenascin-C activity and overexpression of syndecan-4 circumvents the effects of tenascin-C. In this way, tenascin-C and syndecan-4 work together to control fibroblast morphology and signaling and regulate events such as matrix contraction that are essential for efficient tissue repair.

scholarly journals Iterative screen optimization maximizes the efficiency of macromolecular crystallization

2019 ◽  
Vol 75 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Harrison G. Jones ◽  
Daniel Wrapp ◽  
Morgan S. A. Gilman ◽  
Michael B. Battles ◽  
Nianshuang Wang ◽  
...  
Keyword(s):  
Narrow Range ◽  
Three Dimensional ◽  
X Ray ◽  
X Ray Crystallography ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Crystallization Experiment ◽  
Automated Process ◽  
Macromolecular Crystallization ◽  
Rate Limiting

Advances in X-ray crystallography have streamlined the process of determining high-resolution three-dimensional macromolecular structures. However, a rate-limiting step in this process continues to be the generation of crystals that are of sufficient size and quality for subsequent diffraction experiments. Here, iterative screen optimization (ISO), a highly automated process in which the precipitant concentrations of each condition in a crystallization screen are modified based on the results of a prior crystallization experiment, is described. After designing a novel high-throughput crystallization screen to take full advantage of this method, the value of ISO is demonstrated by using it to successfully crystallize a panel of six diverse proteins. The results suggest that ISO is an effective method to obtain macromolecular crystals, particularly for proteins that crystallize under a narrow range of precipitant concentrations.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Sign in / Sign up

Export Citation Format

Share Document