scholarly journals miR-24 triggers epidermal differentiation by controlling actin adhesion and cell migration

2012 ◽  
Vol 199 (2) ◽  
pp. 347-363 ◽  
Author(s):  
Ivano Amelio ◽  
Anna Maria Lena ◽  
Giuditta Viticchiè ◽  
Ruby Shalom-Feuerstein ◽  
Alessandro Terrinoni ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Control Cell ◽  
Human Keratinocytes ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Mouse Epidermis ◽  
Proliferating Cells ◽  
Cell Mobility

During keratinocyte differentiation and stratification, cells undergo extensive remodeling of their actin cytoskeleton, which is important to control cell mobility and to coordinate and stabilize adhesive structures necessary for functional epithelia. Limited knowledge exists on how the actin cytoskeleton is remodeled in epithelial stratification and whether cell shape is a key determinant to trigger terminal differentiation. In this paper, using human keratinocytes and mouse epidermis as models, we implicate miR-24 in actin adhesion dynamics and demonstrate that miR-24 directly controls actin cable formation and cell mobility. miR-24 overexpression in proliferating cells was sufficient to trigger keratinocyte differentiation both in vitro and in vivo and directly repressed cytoskeletal modulators (PAK4, Tks5, and ArhGAP19). Silencing of these targets recapitulated the effects of miR-24 overexpression. Our results uncover a new regulatory pathway involving a differentiation-promoting microribonucleic acid that regulates actin adhesion dynamics in human and mouse epidermis.

scholarly journals The LINC complex transmits integrin-dependent tension to the nuclear lamina and represses epidermal differentiation

2020 ◽  
Author(s):  
Emma Carley ◽  
Rachel K. Stewart ◽  
Abigail Zieman ◽  
Iman Jalilian ◽  
Diane. E. King ◽  
...  
Keyword(s):  
Cell Fate ◽  
Control Cell ◽  
Nuclear Lamina ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Linc Complex ◽  
Force Transmission ◽  
Cell Fate Decisions

AbstractWhile the mechanisms by which chemical signals control cell fate have been well studied, how mechanical inputs impact cell fate decisions are not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells, and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate.

scholarly journals The LINC complex transmits integrin-dependent tension to the nuclear lamina and represses epidermal differentiation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Emma Carley ◽  
Rachel Stewart ◽  
Abigail G Zieman ◽  
Iman Jalilian ◽  
Diane E King ◽  
...  
Keyword(s):  
Cell Fate ◽  
Control Cell ◽  
Nuclear Lamina ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Linc Complex ◽  
Force Transmission ◽  
Cell Fate Decisions

While the mechanisms by which chemical signals control cell fate have been well studied, how mechanical inputs impact cell fate decisions are not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells, and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate.

scholarly journals Phosphoprotein Phosphatase 1 Is Required for Extracellular Calcium-Induced Keratinocyte Differentiation

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chandrama Shrestha ◽  
Yuanyuan Tang ◽  
Hong Fan ◽  
Lusha Li ◽  
Qin Zeng ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Second Messengers ◽  
Human Keratinocytes ◽  
Extracellular Calcium ◽  
Keratinocyte Differentiation ◽  
Differentiation Markers ◽  
Calcium Stimulation ◽  
E Cadherin

Extracellular calcium is a major regulator of keratinocyte differentiation in vitro and appears to play that role in vivo, but the mechanism is unclear. We have previously demonstrated that, following calcium stimulation, PIP5K1αis recruited by the E-cadherin-β-catenin complex to the plasma membrane where it provides the substrate PIP2 for both PI3K and PLC-γ1. This signaling pathway is critical for calcium-induced generation of second messengers including IP3 and intracellular calcium and keratinocyte differentiation. In this study, we explored the upstream regulatory mechanism by which calcium activates PIP5K1αand the role of this activation in calcium-induced keratinocyte differentiation. We found that treatment of human keratinocytes in culture with calcium resulted in an increase in serine dephosphorylation and PIP5K1αactivation. PP1 knockdown blocked extracellular calcium-induced increase in serine dephosphorylation and activity of PIP5K1αand induction of keratinocyte differentiation markers. Knockdown of PLC-γ1, the downstream effector of PIP5K1α, blocked upstream dephosphorylation and PIP5K1αactivation induced by calcium. Coimmunoprecipitation revealed calcium induced recruitment of PP1 to the E-cadherin-catenin-PIP5K1αcomplex in the plasma membrane. These results indicate that PP1 is recruited to the extracellular calcium-dependent E-cadherin-catenin-PIP5K1αcomplex in the plasma membrane to activate PIP5K1α, which is required for PLC-γ1 activation leading to keratinocyte differentiation.

scholarly journals Srf controls satellite cell fusion through the maintenance of actin architecture

2017 ◽  
Vol 217 (2) ◽  
pp. 685-700 ◽  
Author(s):  
Voahangy Randrianarison-Huetz ◽  
Aikaterini Papaefthymiou ◽  
Gaëlle Herledan ◽  
Chiara Noviello ◽  
Ulduz Faradova ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Serum Response Factor ◽  
Control Cell ◽  
Muscle Growth ◽  
Muscle Stem Cells ◽  
Hypertrophic Growth ◽  
Proliferation And Differentiation ◽  
Muscle Homeostasis

Satellite cells (SCs) are adult muscle stem cells that are mobilized when muscle homeostasis is perturbed. Here, we show that serum response factor (Srf) is needed for optimal SC-mediated hypertrophic growth. We identified Srf as a master regulator of SC fusion required in both fusion partners, whereas it was dispensable for SC proliferation and differentiation. We show that SC-specific Srf deletion leads to impaired actin cytoskeleton and report the existence of finger-like actin–based protrusions at fusion sites in vertebrates that were notoriously absent in fusion-defective myoblasts lacking Srf. Restoration of a polymerized actin network by overexpression of an α-actin isoform in Srf mutant SCs rescued their fusion with a control cell in vitro and in vivo and reestablished overload-induced muscle growth. These findings demonstrate the importance of Srf in controlling the organization of actin cytoskeleton and actin-based protrusions for myoblast fusion in mammals and its requirement to achieve efficient hypertrophic myofiber growth.

Overexpression of Krüppel-like factor 5 in esophageal epithelia in vivo leads to increased proliferation in basal but not suprabasal cells

2007 ◽  
Vol 292 (6) ◽  
pp. G1784-G1792 ◽  
Author(s):  
Bree G. Goldstein ◽  
Hann-Hsiang Chao ◽  
Yizeng Yang ◽  
Yuliya A. Yermolina ◽  
John W. Tobias ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Dna Sequences ◽  
Ectopic Expression ◽  
Basal Layer ◽  
Keratinocyte Differentiation ◽  
Basal Cells ◽  
Proliferating Cells ◽  
Barr Virus

Krüppel-like factor 5 ( Klf5; also called IKLF or BTEB2), a zinc-finger transcription factor with proproliferative and transforming properties in vitro, is expressed in proliferating cells of gastrointestinal tract epithelia, including in basal cells of the esophagus. Thus, Klf5 is an excellent candidate to regulate esophageal epithelial proliferation in vivo. Nonetheless, the function of Klf5 in esophageal epithelial homeostasis and tumorigenesis in vivo has not previously been determined. Here, we used the ED- L2 promoter of the Epstein-Barr virus to express Klf5 throughout esophageal epithelia. ED-L2/ Klf5 transgenic mice were born at the appropriate Mendelian ratio, survived to at least 1 yr of age, and showed no evidence of esophageal dysplasia or cancer. Staining for bromodeoxyuridine (BrdU) demonstrated increased proliferation in the basal layer of ED-L2/ Klf5 mice, but no proliferation was seen in suprabasal cells, despite ectopic expression of Klf5 in these cells. Notably, expression of the KLF family member Klf4, which binds the same DNA sequences as Klf5 and which inhibits proliferation and promotes differentiation, was not altered in ED-L2/ Klf5 transgenic mice. In primary esophageal keratinocytes that overexpressed Klf5, expression of Klf4 still inhibited proliferation and promoted differentiation, providing a possible mechanism for the persistence of keratinocyte differentiation in ED-L2/ Klf5 mice. To identify additional targets for Klf5 in esophageal epithelia, we performed functional genomic analyses and identified a total of 15 differentially expressed genes. In summary, while Klf5 positively regulates proliferation in basal cells, it is not sufficient to maintain proliferation in the esophageal epithelium.

scholarly journals Differential expression of cyclophilin isoforms during keratinocyte differentiation

1994 ◽  
Vol 303 (3) ◽  
pp. 863-867 ◽  
Author(s):  
D Chatellard-Gruaz ◽  
J H Saurat ◽  
G Siegenthaler
Keyword(s):  
Human Skin ◽  
Gel Filtration ◽  
Human Keratinocytes ◽  
Immunosuppressive Drug ◽  
Keratinocyte Differentiation ◽  
Normal Human Skin ◽  
Normal Human ◽  
Radiobinding Assay

Cyclophilin A, the major intracellular binding protein for the immunosuppressive drug cyclosporin A (CsA), was studied in human keratinocytes during differentiation both in vivo and in vitro. Analysis of cyclophilin by gel-filtration radiobinding-assay with tritiated CsA showed one specific radioactive peak at 17 kDa. By this technique, the levels of cyclophilin (mean 55.23 +/- 8.43 pmol/mg protein) did not significantly differ during keratinocyte differentiation. When the protein extracts from calcium-induced differentiating keratinocytes and normal human skin were analysed by PAGE radiobinding-assay, two specific radioactive CsA-binding peaks were detected. The major peak (RF 0.13) was expressed in all samples (mean 47.32 +/- 17.53 pmol/mg protein) whereas the minor peak (RF 0.23) was dramatically decreased about 6-fold in abnormally differentiated skin (psoriasis) as well as in non-differentiated keratinocytes. At least six [3H]CsA-binding isoforms with pI values ranging from 5.58 to 7.75 were detected by isoelectrofocusing autoradio-blotting-assay in normal human skin; three of them immunoreacted with antibodies to cyclophilin. These results demonstrated the presence of several cyclophilin isoforms in human epidermal cells and an expression which correlated with the differentiation of human keratinocytes both in vivo and in vitro.

scholarly journals Transient Hyperproliferation of a Transgenic Human Epidermis Expressing Hepatocyte Growth Factor

2002 ◽  
Vol 11 (4) ◽  
pp. 385-395 ◽  
Author(s):  
Karen E. Hamoen ◽  
Jeffrey R. Morgan
Keyword(s):  
Growth Factor ◽  
Hepatocyte Growth Factor ◽  
Human Keratinocytes ◽  
Epidermal Keratinocytes ◽  
Skin Substitutes ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Hepatocyte Growth

Hepatocyte growth factor (HGF) is a fibroblast-derived protein that affects the growth, motility, and differentiation of epithelial cells including epidermal keratinocytes. To investigate the role of HGF in cutaneous biology and to explore the possibility of using it in a tissue engineering approach, we used retroviral-mediated gene transfer to introduce the gene encoding human HGF into diploid human keratinocytes. Modified cells synthesized and secreted significant levels of HGF in vitro and the proliferation of keratinocytes expressing HGF was enhanced compared with control unmodified cells. To investigate the effects of HGF in vivo, we grafted modified keratinocytes expressing HGF onto athymic mice using acellular dermis as a substrate. When compared with controls, HGF-expressing keratinocytes formed a hyperproliferative epidermis. The epidermis was thicker, had more cells per length of basement membrane, and had increased numbers of Ki-67-positive proliferating cells, many of which were suprabasal in location. Hyperproliferation subsided and the epidermis was equivalent to controls by 2 weeks, a time frame that coincides with healing of the graft. Transient hyperproliferation may be linked to the loss of factors present in the wound that activate HGF. These data suggest that genetically modified skin substitutes secreting HGF may have applications in wound closure and the promotion of wound healing.

scholarly journals The Aryl Hydrocarbon Receptor senses the Henna pigment Lawsone and mediates Yin-Yang effects on skin homeostasis

2018 ◽  
Author(s):  
Laura Lozza ◽  
Pedro Moura-Alves ◽  
Teresa Domaszewska ◽  
Carolina Lage Crespo ◽  
Ioana Streata ◽  
...  
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Skin Irritation ◽  
Human Keratinocytes ◽  
Skin Inflammation ◽  
Keratinocyte Differentiation ◽  
Aryl Hydrocarbon ◽  
Differentiation And Proliferation ◽  
Potential Use

As a first host barrier, the skin is constantly exposed to environmental insults that perturb its integrity. Tight regulation of skin homeostasis is largely controlled by the aryl hydrocarbon receptor (AhR). Here, we demonstrate that Henna and its major pigment, the naphthoquinone Lawsone activate AhR, both in vitro and in vivo. In human keratinocytes and epidermis equivalents, Lawsone exposure enhances the production of late epidermal proteins, impacts keratinocyte differentiation and proliferation, and regulates skin inflammation. To determine the potential use of Lawsone for therapeutic application, we harnessed human, murine and zebrafish models. In skin regeneration models, Lawsone interferes with physiological tissue regeneration and inhibits wound healing. Conversely, in a human acute dermatitis model, topical application of a Lawsone-containing cream ameliorates skin irritation. Altogether, our study reveals how a widely used natural plant pigment is sensed by the host receptor AhR, and how the physiopathological context determines beneficial and detrimental outcomes.

iTSP-PseAAC: Identify Tumor Suppressor Proteins by Using Fully Connected Neural Network and PseAAC

2021 ◽  
Vol 15 ◽  
Author(s):  
Muhammad Awais ◽  
Waqar Hussain ◽  
Nouman Rasool ◽  
Yaser Daanial Khan
Keyword(s):  
Tumor Suppressor ◽  
Cross Validation ◽  
Control Cell ◽  
Normal Function ◽  
In Vivo Studies ◽  
Tumor Suppressor Proteins ◽  
Proposed Model ◽  
Self Consistency

Background: The uncontrolled growth due to accumulation of genetic and epigenetic changes as a result of loss or reduction in the normal function of Tumor Suppressor Genes (TSGs) and Pro-oncogenes is known as cancer. TSGs control cell division and growth by repairing of DNA mistakes during replication and restrict the unwanted proliferation of a cell or activities, those are the part of tumor production. Objectives: This study aims to propose a novel, accurate, user-friendly model to predict tumor suppressor proteins, which would be freely available to experimental molecular biologists to assist them using in vitro and in vivo studies. Methods: The predictor model has used the input feature vector (IFV) calculated from the physicochemical properties of proteins based on FCNN to compute the accuracy, sensitivity, specificity, and MCC. The proposed model was validated against different exhaustive validation techniques i.e. self-consistency and cross-validation. Results: Using self-consistency, the accuracy is 99%, for cross-validation and independent testing has 99.80% and 100% accuracy respectively. The overall accuracy of the proposed model is 99%, sensitivity value 98% and specificity 99% and F1-score was 0.99. Conclusion: It concludes, the proposed model for prediction of the tumor suppressor proteins can predict the tumor suppressor proteins efficiently, but it still has space for improvements in computational ways as the protein sequences may rapidly increase, day by day.

scholarly journals Long-Term Severe In Vitro Hypoxia Exposure Enhances the Vascularization Potential of Human Adipose Tissue-Derived Stromal Vascular Fraction Cell Engineered Tissues

2021 ◽  
Vol 22 (15) ◽  
pp. 7920
Author(s):  
Myroslava Mytsyk ◽  
Giulia Cerino ◽  
Gregory Reid ◽  
Laia Gili Sole ◽  
Friedrich S. Eckstein ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Therapeutic Potential ◽  
Stromal Vascular Fraction ◽  
Human Adipose Tissue ◽  
Bioreactor Culture ◽  
Proliferating Cells ◽  
Angiogenic Potential ◽  
Engineered Tissues

The therapeutic potential of mesenchymal stromal/stem cells (MSC) for treating cardiac ischemia strongly depends on their paracrine-mediated effects and their engraftment capacity in a hostile environment such as the infarcted myocardium. Adipose tissue-derived stromal vascular fraction (SVF) cells are a mixed population composed mainly of MSC and vascular cells, well known for their high angiogenic potential. A previous study showed that the angiogenic potential of SVF cells was further increased following their in vitro organization in an engineered tissue (patch) after perfusion-based bioreactor culture. This study aimed to investigate the possible changes in the cellular SVF composition, in vivo angiogenic potential, as well as engraftment capability upon in vitro culture in harsh hypoxia conditions. This mimics the possible delayed vascularization of the patch upon implantation in a low perfused myocardium. To this purpose, human SVF cells were seeded on a collagen sponge, cultured for 5 days in a perfusion-based bioreactor under normoxia or hypoxia (21% and <1% of oxygen tension, respectively) and subcutaneously implanted in nude rats for 3 and 28 days. Compared to ambient condition culture, hypoxic tension did not alter the SVF composition in vitro, showing similar numbers of MSC as well as endothelial and mural cells. Nevertheless, in vitro hypoxic culture significantly increased the release of vascular endothelial growth factor (p < 0.001) and the number of proliferating cells (p < 0.00001). Moreover, compared to ambient oxygen culture, exposure to hypoxia significantly enhanced the vessel length density in the engineered tissues following 28 days of implantation. The number of human cells and human proliferating cells in hypoxia-cultured constructs was also significantly increased after 3 and 28 days in vivo, compared to normoxia. These findings show that a possible in vivo delay in oxygen supply might not impair the vascularization potential of SVF- patches, which qualifies them for evaluation in a myocardial ischemia model.

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