scholarly journals Vimentin intermediate filaments mediate cell shape on visco-elastic substrates

2020 ◽  
Author(s):  
Maxx Swoger ◽  
Sarthak Gupta ◽  
Elisabeth E. Charrier ◽  
Michael Bates ◽  
Heidi Hehnly ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Wound Repair ◽  
Null Mouse ◽  
Polyacrylamide Hydrogels ◽  
Polymeric Networks ◽  
Cytoskeletal Network ◽  
Elastic Substrates ◽  
Sense And Respond ◽  
Mediate Cell

AbstractThe ability of cells to take and change shape is a fundamental feature underlying development, wound repair, and tissue maintenance. Central to this process is physical and signaling interactions between the three cytoskeletal polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). Vimentin is an IF protein that is essential to the mechanical resilience of cells and regulates cross-talk amongst the cytoskeleton, but its role in how cells sense and respond to the surrounding extracellular matrix is largely unclear. To investigate vimentin’s role in substrate sensing, we designed polyacrylamide hydrogels that mimic the elastic and viscoelastic nature of in vivo tissues. Using wild-type and vimentin-null mouse embryonic fibroblasts, we show that vimentin enhances cell spreading on viscoelastic substrates, even though it has little effect in the limit of purely elastic substrates. Our results provide compelling evidence that the vimentin cytoskeletal network is a physical modulator of how cells sense and respond to mechanical properties of their extracellular environment.

scholarly journals Loss of keratin 6 (K6) proteins reveals a function for intermediate filaments during wound repair

2003 ◽  
Vol 163 (2) ◽  
pp. 327-337 ◽  
Author(s):  
Pauline Wong ◽  
Pierre A. Coulombe
Keyword(s):  
Gene Expression ◽  
Wound Repair ◽  
Tissue Injury ◽  
Blood Clot ◽  
Explant Culture ◽  
Null Mouse ◽  
Actin Organization ◽  
Mammalian Tissues

The ability to heal wounds is vital to all organisms. In mammalian tissues, alterations in intermediate filament (IF) gene expression represent an early reaction of cells surviving injury. We investigated the role of keratin IFs during the epithelialization of skin wounds using a keratin 6α and 6β (K6α/K6β)-null mouse model. In skin explant culture, null keratinocytes exhibit an enhanced epithelialization potential due to increased migration. The extent of the phenotype is strain dependent, and is accompanied by alterations in keratin IF and F-actin organization. However, in wounded skin in vivo, null keratinocytes rupture as they attempt to migrate under the blood clot. Fragility of the K6α/K6β-null epidermis is confirmed when applying trauma to chemically treated skin. We propose that the alterations in IF gene expression after tissue injury foster a compromise between the need to display the cellular pliability necessary for timely migration and the requirement for resilience sufficient to withstand the rigors of a wound site.

scholarly journals Co-Transplantation of Skin-Derived Precursors and Collagen Sponge Facilitates Diabetic Wound Healing by Promoting Local Vascular Regeneration

2015 ◽  
Vol 37 (5) ◽  
pp. 1725-1737 ◽  
Author(s):  
Tingyu Ke ◽  
Mei Yang ◽  
Duo Mao ◽  
Meifeng Zhu ◽  
Yongzhe Che ◽  
...  
Keyword(s):  
Wound Healing ◽  
Wound Repair ◽  
Expression Patterns ◽  
Collagen Sponge ◽  
Health Concern ◽  
Diabetic Wound ◽  
Paracrine Signalling ◽  
Vascular Regeneration ◽  
Diabetic Wound Healing

Background/Aims: Impaired diabetes wound healing can often lead to serious complications and remains a major health concern due to the lack of effective therapeutic approaches. Compromised angiogenesis, disrupted growth factor and cytokine activity are all attributable to diabetic wound healing impairment. The skin-derived precursors (SKPs) have been shown to differentiate into vascular and nerve cells, both of which are crucial components for wound repair. Given their easy accessibility and multipotency, the SKPs were proposed as an ideal therapeutic candidate for diabetic wound healing. Since the efficacy of cell therapy is limited by poor cell survival, collagen sponge was employed for better SKPs delivery. Methods: SKPs were isolated and transplanted directly to the wound areas of diabetic mice in the absence and presence of collagen sponge. The effects of SKPs and/or collagen sponge on diabetic wound healing were examined histologically as well as immunostaining of isolectin and α-SMA. Mechanisms via which the SKPs facilitate wound healing were then investigated by transplanting SKPs that have been pre-labelled with a fluorescence dye, Dil. Expression patterns of Dil and an SKP marker, nestin, was also examined. Results and Conclusion: Accelerated wound healing and enhanced local capillary regeneration could be observed 14 days after skin ablation from both SKPs and collagen sponge co-transplanted and collagen sponge only groups. Subsequent analyses further revealed superior pro-angiogenic effects from the SKP and collagen sponge co-delivered group, which are mainly attributable to in vivo transdifferentation and paracrine signalling of the SKPs.

scholarly journals Cell-substratum interaction of cultured avian osteoclasts is mediated by specific adhesion structures.

1984 ◽  
Vol 99 (5) ◽  
pp. 1696-1705 ◽  
Author(s):  
P C Marchisio ◽  
D Cirillo ◽  
L Naldini ◽  
M V Primavera ◽  
A Teti ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Intermediate Filaments ◽  
Immunofluorescence Microscopy ◽  
Laying Hens ◽  
Cell Types ◽  
Medullary Bone ◽  
Transformed Cell ◽  
The Core ◽  
Low Calcium Diet

The cell-substratum interaction was studied in cultures of osteoclasts isolated from the medullary bone of laying hens kept on low calcium diet. In fully spread osteoclasts, cell-substratum adhesion mostly occurred within a continuous paramarginal area that corresponded also to the location of a thick network of intermediate filaments of the vimentin type. In this area, regular rows of short protrusions contacting the substratum and often forming a cup-shaped adhesion area were observed in the electron microscope. These short protrusions showed a core of F-actin-containing material presumably organized as a network of microfilaments and surrounded by a rosette-like structure in which vinculin and alpha-actinin were found by immunofluorescence microscopy. Rosettes were superposable to dark circles in interference-reflection microscopy and thus represented circular forms of close cell-substratum contact. The core of ventral protrusions also contained, beside F-actin, fimbrin and alpha-actinin. Villin was absent. This form of cell-substratum contact occurring at the tip of a short ventral protrusion differed from other forms of cell-substratum contact and represented an osteoclast-specific adhesion device that might also be present in in vivo osteoclasts as well as in other normal and transformed cell types.

Abstract 13373: Exercise Improves Angiogenic Function of Circulating Exosomes in Type 2 Diabetes: Role of Extracellular SOD

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Kareem Abdelsaid ◽  
Sudhahar Varadarajan ◽  
Archita Das ◽  
Yutao Liu ◽  
Xuexiu Fang ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Wound Healing ◽  
Endothelial Dysfunction ◽  
Wound Repair ◽  
Cell Communication ◽  
Tube Formation ◽  
Skin Wound ◽  
Skin Wound Healing

Background: Exosomes, key mediators of cell-cell communication, derived from type 2 diabetes mellitus (T2DM) have detrimental effects. Exercise not only improves endothelial dysfunction and angiogenesis in T2DM but also induces secretion of exosomes into circulation. Extracellular superoxide dismutase (ecSOD) is a major secretory Cu containing antioxidant enzyme that catalyzes dismutation of O 2 •- to H 2 O 2 and its full activity requires Cu transporter ATP7A. We reported that ecSOD-derived H 2 O 2 in endothelial cells (ECs) enhances angiogenesis while impaired ATP7A-ecSOD axis in diabetes induces endothelial dysfunction. Here we examined whether exercise-derived exosomes (Exe-Exo) may have pro-angiogenic effects via regulating ATP7A-ecSOD axis in T2DM. Results: Two weeks of voluntary wheel exercise of control C57Bl6 mice increased plasma exosome levels (6.2-fold) characterized by Nanosight, TEM and exosome markers (CD63, CD81, Tsg101). Treatment of HUVECs with equal number of exosomes revealed that angiogenic responses such as EC migration (1.8-fold) and tube formation (1.7-fold) were significantly enhanced by Exe-Exo compared to sedentary-derived exosomes (Sed-Exo). This was associated with increased ATP7A (2.9-fold) and ecSOD (1.4-fold) expression in Exe-Exo. Sed-Exo from high fat-induced T2DM mice significantly decreased EC migration (40%) and tube formation (10%) as well as ATP7A expression (28%) compared to Sed-Exo from control mice, which were restored by T2DM Exe-Exo, but not by T2DM/ecSOD KO Exe-Exo. Furthermore, exosomes overexpressing ecSOD (ecSOD-Exo) which mimic exercise increased angiogenesis and H2O2 levels in ECs, which were inhibited by overexpression of catalase. In vivo, skin wound healing model showed that direct application of T2DM Sed-Exo delayed while T2DM Exe-Exo enhanced wound healing of control mice. Furthermore, defective wound healing in T2DM mice or ecSOD KO mice were rescued by ecSOD-Exo application. Conclusion: Exercise training improves pro-angiogenic function of circulating exosomes in T2DM via increasing ATP7A-ecSOD axis, which may provide an effective therapy for promoting angiogenesis and wound repair in metabolic and cardiovascular diseases.

Gene transfer of hepatocyte growth factor by electroporation reduces bleomycin-induced lung fibrosis

2007 ◽  
Vol 292 (2) ◽  
pp. L529-L536 ◽  
Author(s):  
Amiq Gazdhar ◽  
Patrick Fachinger ◽  
Coretta van Leer ◽  
Jaroslaw Pierog ◽  
Mathias Gugger ◽  
...  
Keyword(s):  
Growth Factor ◽  
Gene Transfer ◽  
Pulmonary Fibrosis ◽  
Wound Repair ◽  
Alveolar Epithelial Cells ◽  
Epithelial Repair ◽  
Alveolar Epithelial ◽  
Hepatocyte Growth

Abnormal alveolar wound repair contributes to the development of pulmonary fibrosis after lung injury. Hepatocyte growth factor (HGF) is a potent mitogenic factor for alveolar epithelial cells and may therefore improve alveolar epithelial repair in vitro and in vivo. We hypothesized that HGF could increase alveolar epithelial repair in vitro and improve pulmonary fibrosis in vivo. Alveolar wound repair in vitro was determined using an epithelial wound repair model with HGF-transfected A549 alveolar epithelial cells. Electroporation-mediated, nonviral gene transfer of HGF in vivo was performed 7 days after bleomycin-induced lung injury in the rat. Alveolar epithelial repair in vitro was increased after transfection of wounded epithelial monolayers with a plasmid encoding human HGF, pCikhHGF [human HGF (hHGF) gene expressed from the cytomegalovirus (CMV) immediate-early promoter and enhancer] compared with medium control. Electroporation-mediated in vivo HGF gene transfer using pCikhHGF 7 days after intratracheal bleomycin reduced pulmonary fibrosis as assessed by histology and hydroxyproline determination 14 days after bleomycin compared with controls treated with the same vector not containing the HGF sequence (pCik). Lung epithelial cell proliferation was increased and apoptosis reduced in hHGF-treated lungs compared with controls, suggesting increased alveolar epithelial repair in vivo. In addition, profibrotic transforming growth factor-β1 (TGF-β1) was decreased in hHGF-treated lungs, indicating an involvement of TGF-β1 in hHGF-induced reduction of lung fibrosis. In conclusion, electroporation-mediated gene transfer of hHGF decreases bleomycin-induced pulmonary fibrosis, possibly by increasing alveolar epithelial cell proliferation and reducing apoptosis, resulting in improved alveolar wound repair.

scholarly journals Hypoxic stress underlies defects in erythroblast islands in the Rb-null mouse

Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 2173-2181 ◽  
Author(s):  
Benjamin T. Spike ◽  
Benjamin C. Dibling ◽  
Kay F. Macleod
Keyword(s):  
Fetal Liver ◽  
Cell Maturation ◽  
Null Mouse ◽  
Hypoxic Stress ◽  
Red Cell ◽  
Exogenous Stress ◽  
Erythroid Maturation ◽  
Definitive Erythropoiesis

Abstract Definitive erythropoiesis occurs in islands composed of a central macrophage in contact with differentiating erythroblasts. Erythroid maturation including enucleation can also occur in the absence of macrophages both in vivo and in vitro. We reported previously that loss of Rb induces cell-autonomous defects in red cell maturation under stress conditions, while other reports have suggested that the failure of Rb-null erythroblasts to enucleate is due to defects in associated macrophages. Here we show that erythropoietic islands are disrupted by hypoxic stress, such as occurs in the Rb-null fetal liver, that Rb−/− macrophages are competent for erythropoietic island formation in the absence of exogenous stress and that enucleation defects persist in Rb-null erythroblasts irrespective of macrophage function.

scholarly journals Inhibition of the oxygen sensor PHD2 in the liver improves survival in lactic acidosis by activating the Cori cycle

2015 ◽  
Vol 112 (37) ◽  
pp. 11642-11647 ◽  
Author(s):  
Tomohiro Suhara ◽  
Takako Hishiki ◽  
Masataka Kasahara ◽  
Noriyo Hayakawa ◽  
Tomoko Oyaizu ◽  
...  
Keyword(s):  
Lactic Acidosis ◽  
Oxygen Sensor ◽  
Lethal Dose ◽  
Hypoxia Inducible Factor ◽  
Tolerance Test ◽  
Null Mouse ◽  
Mice Model ◽  
Hypoxic Response ◽  
Cori Cycle

Loss of prolyl hydroxylase 2 (PHD2) activates the hypoxia-inducible factor-dependent hypoxic response, including anaerobic glycolysis, which causes large amounts of lactate to be released from cells into the circulation. We found that Phd2-null mouse embryonic fibroblasts (MEFs) produced more lactate than wild-type MEFs, as expected, whereas systemic inactivation of PHD2 in mice did not cause hyperlacticacidemia. This unexpected observation led us to hypothesize that the hypoxic response activated in the liver enhances the Cori cycle, a lactate–glucose carbon recycling system between muscle and liver, and thereby decreases circulating lactate. Consistent with this hypothesis, blood lactate levels measured after a treadmill or lactate tolerance test were significantly lower in Phd2-liver-specific knockout (Phd2-LKO) mice than in control mice. An in vivo 13C-labeled lactate incorporation assay revealed that the livers of Phd2-LKO mice produce significantly more glucose derived from 13C-labeled lactate than control mice, suggesting that blockade of PHD2 in the liver ameliorates lactic acidosis by activating gluconeogenesis from lactate. Phd2-LKO mice were resistant to lactic acidosis induced by injection of a lethal dose of lactate, displaying a significant elongation of survival. Moreover, oral administration of a PHD inhibitor improved survival in an endotoxin shock mice model. These data suggest that PHD2 is a potentially novel drug target for the treatment of lactic acidosis, which is a serious and often fatal complication observed in some critically ill patients.

scholarly journals Essential nucleotide- and protein-dependent functions of Actb/β-actin

2018 ◽  
Vol 115 (31) ◽  
pp. 7973-7978 ◽  
Author(s):  
Xiaobai Patrinostro ◽  
Pallabi Roy ◽  
Angus Lindsay ◽  
Christopher M. Chamberlain ◽  
Lauren J. Sundby ◽  
...  
Keyword(s):  
Gene Knockout ◽  
Null Mouse ◽  
Cellular Functions ◽  
Embryonic Fibroblasts ◽  
High Frequency Hearing Loss ◽  
Phenotypic Differences ◽  
Functional Differences ◽  
Actin Protein

The highly similar cytoplasmic β- and γ-actins differ by only four functionally similar amino acids, yet previous in vitro and in vivo data suggest that they support unique functions due to striking phenotypic differences between Actb and Actg1 null mouse and cell models. To determine whether the four amino acid variances were responsible for the functional differences between cytoplasmic actins, we gene edited the endogenous mouse Actb locus to translate γ-actin protein. The resulting mice and primary embryonic fibroblasts completely lacked β-actin protein, but were viable and did not present with the most overt and severe cell and organismal phenotypes observed with gene knockout. Nonetheless, the edited mice exhibited progressive high-frequency hearing loss and degeneration of actin-based stereocilia as previously reported for hair cell-specific Actb knockout mice. Thus, β-actin protein is not required for general cellular functions, but is necessary to maintain auditory stereocilia.

Silencing of junctional adhesion molecule-like protein attenuates atherogenesis and enhances plaque stability in ApoE−/− mice

2019 ◽  
Vol 133 (11) ◽  
pp. 1215-1228 ◽  
Author(s):  
Yu Sun ◽  
Juan Guan ◽  
Yunfeng Hou ◽  
Fei Xue ◽  
Wei Huang ◽  
...  
Keyword(s):  
Adhesion Molecule ◽  
Wound Repair ◽  
Inflammatory Responses ◽  
Atherosclerotic Lesion ◽  
Atherosclerotic Plaques ◽  
Plaque Stability ◽  
Fibrous Cap ◽  
Enhanced Expression

Abstract Background: Although junctional adhesion molecule-like protein (JAML) has recently been implicated in leukocyte recruitment during inflammation and wound repair, its role in atherosclerosis remains to be elucidated. Methods and results: First, we showed that JAML was strongly expressed in atherosclerotic plaques of cardiovascular patients. Similar results were obtained with atherosclerotic plaques of ApoE−/− mice. Co-immunofluorescence staining showed that JAML was mainly expressed in macrophages. Enhanced expression of JAML in cultured macrophages was observed following exposure of the cells to oxLDL. The functional role of JAML in atherosclerosis and macrophages function was assessed by interference of JAML with shRNA in vivo and siRNA in vitro. Silencing of JAML in mice significantly attenuated atherosclerotic lesion formation, reduced necrotic core area, increased plaque fibrous cap thickness, decreased macrophages content and inflammation. In addition, histological staining showed that JAML deficiency promoted plaques to stable phenotype. In vitro, JAML siRNA treatment lowered the expression of inflammatory cytokines in macrophages treated with oxLDL. The mechanism by which JAML mediated the inflammatory responses may be related to the ERK/NF-κB activation. Conclusions: Our results demonstrated that therapeutic drugs which antagonize the function of JAML may be a potentially effective approach to attenuate atherogenesis and enhance plaque stability.

scholarly journals Collagen-Chitosan Composite Powder as a Novel Biomaterial for Chronic Wounds in Hansen Disease-A Clinical Study

2021 ◽  
pp. 154-165
Author(s):  
Pombala Suresh Babu ◽  
Harini Srinivasan ◽  
B. Sai Dhandapani ◽  
C. Rose
Keyword(s):  
Wound Repair ◽  
Composite Powder ◽  
Chronic Wounds ◽  
Waste Product ◽  
Wound Dressings ◽  
Meat Industry ◽  
Before And After ◽  
Hematoxylin And Eosin ◽  
Chitosan Composite

Aims: Natural biomaterials are more suitable than synthetic biomaterials for in vivo applications for treating damaged tissues. Collagen and chitosan are abundantly available natural biomaterials for wound dressings for tissue/wound repair. In this context, collagen-chitosan composite powder has been used to treat chronic wounds in Hansen disease (HD) patients. Place and Duration of Study: CSIR Central Leather Research Institute, Sardar Patel Road, Adyar, Chennai 600021, Southern Railway Headquarters Hospital, Constable Road, Ayanavaram, Chennai 600023, and Gremaltes Hospital, India between June 2013 and July 2020. Methodology: Collagen extracted from bovine rumen, a waste product of meat industry, and a commercially available chitosan were prepared as a composite powder (COL/CS) and applied to chronic wounds in HD patients after debridement and the wound contours were measured by planimetry. Biochemical parameters in blood samples were periodically assessed. Histopathology of wound tissue with Hematoxylin and Eosin and Masson’s Trichrome staining was studied. Matrix Metalloproteinase-9 (MMP9) levels before and after treatment were estimated. Results: Wound healing of 64.2% was obtained with COL/CS treatment and formation of granulation cells was observed early. Hemogram studies have been reported in a regression model with 95% confidence intervals. Histopathology revealed dense collagen fibres and continuity of sub-epithelial layer on 8th day. MMP-9 levels showed collagen integrity after treatment. Conclusion: The novel biocompatible, biodegradable COL/CS wound dressing is a promising biomaterial for management of chronic wounds in Hansen disease patients.

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