scholarly journals An intact keratin network is crucial for mechanical integrity and barrier function in keratinocyte cell sheets

2019 ◽  
Author(s):  
Susanne Karsch ◽  
Fanny Büchau ◽  
Thomas M. Magin ◽  
Andreas Janshoff
Keyword(s):  
Barrier Function ◽  
Time Course ◽  
Mechanical Response ◽  
Adhesion Force ◽  
Cell Junctions ◽  
Force Transmission ◽  
Cell Sheets ◽  
Mechanical Integrity ◽  
Barrier Formation ◽  
Mechanical Homeostasis

AbstractThe isotype-specific composition of the keratin cytoskeleton is important for strong adhesion, force resilience, and barrier function of the epidermis. However, the mechanisms by which keratins regulate these functions are still incompletely understood. In this study, the role and significance of the keratin network for mechanical integrity, force transmission, and barrier formation were analyzed in murine keratinocytes. Following the time-course of single-cell wounding, wildtype (WT) cells slowly closed the gap in a collective fashion involving tightly connected neighboring cells. In contrast, the mechanical response of neighboring cells was compromised in keratin-deficient cells, causing an increased wound area initially and an inefficient overall wound closure. Furthermore, the loss of the keratin network led to impaired, fragmented cell-cell junctions and triggered a profound change in the overall cellular actomyosin architecture. Electrical cell-substrate impedance sensing of cell junctions revealed a dysfunctional barrier in knockout (Kty−/−) compared to WT cells. These findings demonstrate that Kty−/− cells display a novel phenotype characterized by loss of mechanocoupling and failure to form a functional barrier. Re-expression of K5/K14 rescued the barrier defect to a significant extent and reestablished the mechanocoupling with remaining discrepancies likely due to the low abundance of keratins in that setting. Our study reveals the major role of the keratin network for mechanical homeostasis and barrier functionality in keratinocyte layers.

scholarly journals An intact keratin network is crucial for mechanical integrity and barrier function in keratinocyte cell sheets

2020 ◽  
Vol 77 (21) ◽  
pp. 4397-4411 ◽  
Author(s):  
Susanne Karsch ◽  
Fanny Büchau ◽  
Thomas M. Magin ◽  
Andreas Janshoff
Keyword(s):  
Barrier Function ◽  
Cell Sheets ◽  
Mechanical Integrity ◽  
Keratinocyte Cell

scholarly journals Sustained oscillations of epithelial cell sheets

2018 ◽  
Author(s):  
Grégoire Peyret ◽  
Romain Mueller ◽  
Joseph d’Alessandro ◽  
Simon Begnaud ◽  
Philippe Marcq ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Large Scale ◽  
Morphological Changes ◽  
Computational Modelling ◽  
Cell Junctions ◽  
Force Transmission ◽  
Cell Sheets ◽  
Wide Range ◽  
Collective Oscillations

AbstractMorphological changes during development, tissue repair, and disease largely rely on coordinated cell movements and are controlled by the tissue environment. Epithelial cell sheets are often subjected to large scale deformation during tissue formation. The active mechanical environment in which epithelial cells operate have the ability to promote collective oscillations, but how these cellular movements are generated and relate to collective migration remains unclear. Here, combining in vitro experiments and computational modelling we describe a novel mode of collective oscillations in confined epithelial tissues where the oscillatory motion is the dominant contribution to the cellular movements. We show that epithelial cells exhibit large-scale coherent oscillations when constrained within micro-patterns of varying shapes and sizes, and that their period and amplitude are set by the smallest confinement dimension. Using molecular perturbations, we then demonstrate that force transmission at cell-cell junctions and its coupling to cell polarity are pivotal for the generation of these collective movements. We find that the resulting tissue deformations are sufficient to trigger mechanotransduction within cells, potentially affecting a wide range of cellular processes.

scholarly journals Brick Strex: a robust device built of LEGO bricks for mechanical manipulation of cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elina Mäntylä ◽  
Teemu O. Ihalainen
Keyword(s):  
Molecular Mechanisms ◽  
Compressive Force ◽  
Tissue Mechanics ◽  
Cell Junctions ◽  
Physical Factors ◽  
Force Transmission ◽  
Cell Nuclei ◽  
Microscopy Imaging ◽  
Robust Solution ◽  
Mechanical Manipulation

AbstractCellular forces, mechanics and other physical factors are important co-regulators of normal cell and tissue physiology. These cues are often misregulated in diseases such as cancer, where altered tissue mechanics contribute to the disease progression. Furthermore, intercellular tensile and compressive force-related signaling is highlighted in collective cell behavior during development. However, the mechanistic understanding on the role of physical forces in regulation of cellular physiology, including gene expression and signaling, is still lacking. This is partly because studies on the molecular mechanisms of force transmission require easily controllable experimental designs. These approaches should enable both easy mechanical manipulation of cells and, importantly, readouts ranging from microscopy imaging to biochemical assays. To achieve a robust solution for mechanical manipulation of cells, we developed devices built of LEGO bricks allowing manual, motorized and/or cyclic cell stretching and compression studies. By using these devices, we show that $$\upbeta$$ β -catenin responds differentially to epithelial monolayer stretching and lateral compression, either localizing more to the cell nuclei or cell–cell junctions, respectively. In addition, we show that epithelial compression drives cytoplasmic retention and phosphorylation of transcription coregulator YAP1. We provide a complete part listing and video assembly instructions, allowing other researchers to build and use the devices in cellular mechanics-related studies.

scholarly journals Laminin-driven Epac/Rap1 regulation of epithelial barriers on decellularized matrix

2019 ◽  
Author(s):  
Bethany M. Young ◽  
Keerthana Shankar ◽  
Cindy K. Tho ◽  
Amanda R. Pellegrino ◽  
Rebecca L. Heise
Keyword(s):  
Barrier Function ◽  
Cellular Response ◽  
Alveolar Epithelium ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Main Challenge ◽  
Barrier Formation ◽  
Epithelial Barriers ◽  
Molecular Therapeutic

ABSTRACTDecellularized tissues offer a unique tool for developing regenerative biomaterials orin vitroplatforms for the study of cell-extracellular matrix (ECM) interactions. One main challenge associated with decellularized lung tissue is that ECM components can be stripped away or altered by the detergents used to remove cellular debris. Without characterizing the composition of lung decellularized ECM (dECM) and the cellular response caused by the altered composition, it is difficult to utilize dECM for regeneration and specifically, engineering the complexities of the alveolar-capillary barrier. This study takes steps towards uncovering if dECM must be enhanced with lost ECM proteins to achieve proper epithelial barrier formation. To achieve this, epithelial barrier function was assessed on dECM coatings with and without the systematic addition of several key basement membrane proteins. After comparing barrier function on collagen, fibronectin, laminin, and dECM in varying combinations as anin vitrocoating, the alveolar epithelium exhibited superior barrier function when dECM was supplemented with laminin as evidenced by trans-epithelial electrical resistance (TEER) and permeability assays. Increased barrier resistance with laminin addition was associated with upregulation of Claudin-18, E- cadherin, and junction adhesion molecule (JAM)-A, and stabilization of zonula occludens (ZO)-1 at junction complexes. The Epac/Rap1 pathway was observed to play a role in the ECM-mediated barrier function determined by protein expression and Epac inhibition. These findings reveal potential ECM coatings and molecular therapeutic targets for improved regeneration with decellularized scaffolds or edema related pathologies.

scholarly journals MYADM controls endothelial barrier function through ERM-dependent regulation of ICAM-1 expression

2013 ◽  
Vol 24 (4) ◽  
pp. 483-494 ◽  
Author(s):  
Juan F. Aranda ◽  
Natalia Reglero-Real ◽  
Beatriz Marcos-Ramiro ◽  
Ana Ruiz-Sáenz ◽  
Laura Fernández-Martín ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Inflammatory Response ◽  
Barrier Function ◽  
Leukocyte Adhesion ◽  
Cell Junctions ◽  
Membrane Domains ◽  
Filamentous Actin ◽  
Cytokine Tumor Necrosis Factor ◽  
Factor Α

The endothelium maintains a barrier between blood and tissue that becomes more permeable during inflammation. Membrane rafts are ordered assemblies of cholesterol, glycolipids, and proteins that modulate proinflammatory cell signaling and barrier function. In epithelial cells, the MAL family members MAL, MAL2, and myeloid-associated differentiation marker (MYADM) regulate the function and dynamics of ordered membrane domains. We analyzed the expression of these three proteins in human endothelial cells and found that only MYADM is expressed. MYADM was confined in ordered domains at the plasma membrane, where it partially colocalized with filamentous actin and cell–cell junctions. Small interfering RNA (siRNA)-mediated MYADM knockdown increased permeability, ICAM-1 expression, and leukocyte adhesion, all of which are features of an inflammatory response. Barrier function decrease in MYADM-silenced cells was dependent on ICAM-1 expression. Membrane domains and the underlying actin cytoskeleton can regulate each other and are connected by ezrin, radixin, and moesin (ERM) proteins. In endothelial cells, MYADM knockdown induced ERM activation. Triple-ERM knockdown partially inhibited ICAM-1 increase induced by MYADM siRNA. Importantly, ERM knockdown also reduced ICAM-1 expression in response to the proinflammatory cytokine tumor necrosis factor-α. MYADM therefore regulates the connection between the plasma membrane and the cortical cytoskeleton and so can control the endothelial inflammatory response.

scholarly journals MiR-144 mediates Nrf2 inhibition and alveolar epithelial dysfunction in HIV-1 transgenic rats

2019 ◽  
Vol 317 (2) ◽  
pp. C390-C397 ◽  
Author(s):  
Abiodun T. Kukoyi ◽  
Xian Fan ◽  
Bashar S. Staitieh ◽  
Brooks M. Hybertson ◽  
Bifeng Gao ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Barrier Function ◽  
Transgene Expression ◽  
Antioxidant Defenses ◽  
Transgenic Rats ◽  
Alveolar Epithelial ◽  
Barrier Formation ◽  
Hiv 1 ◽  
Expression And Activity

Chronic HIV infection causes redox stress and increases the risk of acute and chronic lung injury, even when individuals are adherent to antiretroviral therapy. HIV-1 transgene expression in rats inhibits nuclear factor (erythroid-derived 2)-like 2 (Nrf2), which regulates antioxidant defenses and alveolar epithelial cell (AEC) barrier function, but the mechanism is unknown. In this study, we present novel evidence that these pathological effects of HIV are mediated by microRNA-144 (miR-144). HIV-1 transgene expression in vivo increases the expression of miR-144 in the alveolar epithelium, and this can be replicated by direct exposure of naïve primary AECs to either Tat or gp120 ex vivo. Further, treating naïve primary AECs with a miR-144 mimic decreased the expression and activity of Nrf2 and inhibited their barrier formation. In contrast, treatment with a miR-144 antagomir increased the expression and activity of Nrf2 and improved barrier function in primary AECs isolated from HIV-1 transgenic rats. Importantly, either delivering the miR-144 antagomir intratracheally, or directly activating Nrf2 by dietary treatment with PB123, increased Nrf2 expression and barrier formation in HIV-1 transgenic rat AECs. This study provides new experimental evidence that HIV-induced inhibition of Nrf2 and consequent AEC barrier dysfunction are mediated via miR-144, and that these pathophysiological effects can be mitigated in vivo by either directly antagonizing miR-144 or activating Nrf2. Our findings suggest that targeting the inhibition of Nrf2 in individuals living with HIV could enhance their lung health and decrease the lung-specific morbidity and mortality that persists despite antiretroviral therapy.

scholarly journals Heterogeneity of barrier function in the lung reflects diversity in endothelial cell junctions

2008 ◽  
Vol 75 (3) ◽  
pp. 391-402 ◽  
Author(s):  
Solomon F. Ofori-Acquah ◽  
Judy King ◽  
Norbert Voelkel ◽  
Kane L. Schaphorst ◽  
Troy Stevens
Keyword(s):  
Endothelial Cell ◽  
Barrier Function ◽  
Cell Junctions

The Influence of Mild Hypothermia on the Pharmacokinetics and Time Course of Action of Neostigmine in Anesthetized Volunteers

2002 ◽  
Vol 97 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Tom Heier ◽  
David Clough ◽  
Peter M. C. Wright ◽  
Manohar L. Sharma ◽  
Daniel I. Sessler ◽  
...  
Keyword(s):  
Time Course ◽  
Mechanical Response ◽  
Mild Hypothermia ◽  
Neuromuscular Block ◽  
Onset Time ◽  
Volume Of Distribution ◽  
Maximum Effect ◽  
Surface Cooling ◽  
Duration Of Action ◽  
Course Of Action

Background The pharmacokinetics, maximum effect, and time course of action of neostigmine were studied in seven human volunteers. Methods Each volunteer was studied twice, during both normothermia and hypothermia. Anesthesia was induced with 30 microg/kg alfentanil and 3 mg/kg propofol, and was maintained with 60-70% nitrous oxide and 0.7-0.9% isoflurane. The mechanical response of the adductor pollicis to train-of-four stimulation of the ulnar nerve was recorded, and central body temperature maintained stable at either less than 34.5 degrees C or greater than 36.5 degrees C by surface cooling or warming. Before neostigmine administration, a stable 5% twitch height was obtained by an infusion of vecuronium, and the infusion rate remained unchanged thereafter. Neostigmine, 70 microg/kg, was then infused over 2 min, and blood samples for estimation of neostigmine concentrations were collected at intervals for 240 min. Results With hypothermia, the central volume of distribution of neostigmine decreased by 38%, and onset time of maximum effect increased (4.6 vs. 5.6 min). Hypothermia did not change the clearance (696 ml/min), maximum effect, or duration of action of neostigmine. Conclusions The efficacy of neostigmine as an antagonist of vecuronium-induced neuromuscular block is not altered by mild hypothermia.

scholarly journals Correction: Talin tension sensor reveals novel features of focal adhesion force transmission and mechanosensitivity

2016 ◽  
Vol 214 (2) ◽  
pp. 231-231 ◽  
Author(s):  
Abhishek Kumar ◽  
Mingxing Ouyang ◽  
Koen Van den Dries ◽  
Ewan James McGhee ◽  
Keiichiro Tanaka ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Adhesion Force ◽  
Force Transmission ◽  
Tension Sensor
Sign in / Sign up

Export Citation Format

Share Document