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BioRxiv : the Preprint Server For... Jun 2024Cellular mechanotransduction, a process central to cell biology, embryogenesis, adult physiology and multiple diseases, is thought to be mediated by force-driven changes...
Cellular mechanotransduction, a process central to cell biology, embryogenesis, adult physiology and multiple diseases, is thought to be mediated by force-driven changes in protein conformation that control protein function. However, methods to study proteins under defined mechanical loads on a biochemical scale are lacking. We report the development of a DNA based device in which the transition between single-stranded and double-stranded DNA applies tension to an attached protein. Using a fragment of the talin rod domain as a test case, negative-stain electron microscopy reveals programmable extension while pull down assays show tension-induced binding to two ligands, ARPC5L and vinculin, known to bind to cryptic sites inside the talin structure. These results demonstrate the utility of the DNA clamp for biochemical studies and potential structural analysis.
PubMed: 38895381
DOI: 10.1101/2024.06.06.597759 -
Antioxidants (Basel, Switzerland) Jan 2024Diabetes can disrupt physiological wound healing, caused by decreased levels or impaired activity of angiogenic factors. This can contribute to chronic inflammation,...
Diabetes can disrupt physiological wound healing, caused by decreased levels or impaired activity of angiogenic factors. This can contribute to chronic inflammation, poor formation of new blood vessels, and delayed re-epithelialization. The present study describes the preclinical application of medical gas plasma to treat a dermal, full-thickness ear wound in streptozotocin (STZ)-induced diabetic mice. Gas plasma-mediated effects occurred in both sexes but with gender-specific differences. Hyperspectral imaging demonstrated gas plasma therapy changing microcirculatory parameters, particularly oxygen saturation levels during wound healing, presumably due to the gas plasma's tissue delivery of reactive species and other bioactive components. In addition, gas plasma treatment significantly affected cell adhesion by regulating focal adhesion kinase and vinculin, which is important in maintaining skin barrier function by regulating syndecan expression and increasing re-epithelialization. An anticipated stimulation of blood vessel formation was detected via transcriptional and translational increase of angiogenic factors in gas plasma-exposed wound tissue. Moreover, gas plasma treatment significantly affected inflammation by modulating systemic growth factors and cytokine levels. The presented findings may help explain the mode of action of successful clinical plasma therapy of wounds of diabetic patients.
PubMed: 38247492
DOI: 10.3390/antiox13010068 -
Journal of Biomedical Optics Aug 2023Forces inside cells play a fundamental role in tissue growth, affecting important processes such as cancer cell migration or tissue repair after injury. Förster...
SIGNIFICANCE
Forces inside cells play a fundamental role in tissue growth, affecting important processes such as cancer cell migration or tissue repair after injury. Förster resonance energy transfer (FRET)-based tension sensors are a remarkable tool for studying these forces and should be made easier to use.
AIM
We prove that absolute FRET efficiency can be measured on a simple setup, an order of magnitude more cost-effective than a standard FRET microscopy setup, by applying it to vinculin tension sensors (VinTS) at the focal adhesions of live CHO-K1 cells.
APPROACH
Our setup located at Université Paris-Saclay acquires donor and acceptor fluorescence in parallel on two low-cost CMOS cameras and uses two LEDs for rapid switching of the excitation wavelength at a reduced cost. The calibration required to extract FRET efficiency was achieved using a single construct (TSMod). FRET efficiencies were measured for VinTS and the tail-less control VinTL, lacking the actin-binding domain of vinculin. Measurements were confirmed on the same cell type using a more standard intensity-based setup located at Rutgers University.
RESULTS
The average FRET efficiency of VinTS () over more than 10,000 focal adhesions is significantly lower () than that of VinTL (), our control that is insensitive to force, in agreement with the force exerted on vinculin at focal adhesions. Attachment of the CHO-K1 cells on fibronectin decreases FRET efficiency, thus increasing the force, compared with poly-lysine. FRET efficiency for the VinTL control is consistent with all measurements currently available in the literature, confirming the validity of our measurements and hence of our simpler setup.
CONCLUSIONS
Force measurements, resolved spatially inside a cell, can be achieved using FRET-based tension sensors with a cost effective intensity-based setup. This will facilitate combining FRET with techniques for applying controlled forces such as optical tweezers.
Topics: Humans; Fluorescence Resonance Energy Transfer; Focal Adhesions; Vinculin; Cost-Benefit Analysis; Mechanical Phenomena
PubMed: 37441563
DOI: 10.1117/1.JBO.28.8.082808 -
Cells May 2024Epithelial-mesenchymal transition (EMT) is a process during which epithelial cells lose epithelial characteristics and gain mesenchymal features. Here, we used several...
Epithelial-mesenchymal transition (EMT) is a process during which epithelial cells lose epithelial characteristics and gain mesenchymal features. Here, we used several cell models to study migratory activity and redistribution of cell-cell adhesion proteins in cells in different EMT states: EGF-induced EMT of epithelial IAR-20 cells; IAR-6-1 cells with a hybrid epithelial-mesenchymal phenotype; and their more mesenchymal derivatives, IAR-6-1-DNE cells lacking adherens junctions. In migrating cells, the cell-cell adhesion protein α-catenin accumulated at the leading edges along with ArpC2/p34 and α-actinin. Suppression of α-catenin shifted cell morphology from fibroblast-like to discoid and attenuated cell migration. Expression of exogenous α-catenin in MDA-MB-468 cells devoid of α-catenin drastically increased their migratory capabilities. The Y654 phosphorylated form of β-catenin was detected at integrin adhesion complexes (IACs). Co-immunoprecipitation studies indicated that α-catenin and pY654-β-catenin were associated with IAC proteins: vinculin, zyxin, and α-actinin. Taken together, these data suggest that in cells undergoing EMT, catenins not participating in assembly of adherens junctions may affect cell migration.
Topics: Animals; Actin Cytoskeleton; Actinin; Adherens Junctions; alpha Catenin; beta Catenin; Cell Adhesion; Cell Line, Tumor; Cell Movement; Epithelial Cells; Epithelial-Mesenchymal Transition; Integrins; Phosphorylation; Vinculin; Zyxin; Rats
PubMed: 38727316
DOI: 10.3390/cells13090780 -
Research Square Feb 2024Curvature is a critical factor in cornea mechanobiology, but its impact on phenotypic alterations and extracellular matrix remodeling of cornea stroma remains unclear....
Curvature is a critical factor in cornea mechanobiology, but its impact on phenotypic alterations and extracellular matrix remodeling of cornea stroma remains unclear. In this work, we investigated how curvature influences the corneal stroma using a hydraulically controlled curvature array chip. The responses of stromal cells to low, medium, and high curvatures were observed by preparing three phenotypes of corneal stromal cells: corneal keratocytes, fibroblasts, and myofibroblasts. Keratocytes exhibited phenotypic alterations in response to curvature changes, notably including a decrease in ALDH3 expression and an increase in α-SMA expression. For focal adhesion, corneal fibroblast and myofibroblasts showed enhanced vinculin localization in response to curvature, while corneal keratocytes presented reduced vinculin expression. For cell alignment and ECM expression, most stromal cells under all curvatures showed a radially organized f-actin and collagen fibrils. Interestingly, for corneal fibroblast under medium curvature, we observed orthogonal cell alignment, which is linked to the unique hoop and meridional stress profiles of the curved surface. Furthermore, lumican expression was upregulated in corneal keratocytes, and keratocan expression was increased in corneal fibroblasts and myofibroblasts due to curvature. These results demonstrate that curvature influences both the phenotype of corneal stromal cells and the structural organization of corneal stroma tissue without any external stimuli. This curvature-dependent behavior of corneal stromal cells presents potential opportunities for creating therapeutic strategies for corneal shape dysfunctions.
PubMed: 38464213
DOI: 10.21203/rs.3.rs-3973873/v1 -
Clinical Proteomics Mar 2024Cardiac rupture (CR) is a rare but catastrophic mechanical complication of acute myocardial infarction (AMI) that seriously threatens human health. However, the reliable...
BACKGROUND
Cardiac rupture (CR) is a rare but catastrophic mechanical complication of acute myocardial infarction (AMI) that seriously threatens human health. However, the reliable biomarkers for clinical diagnosis and the underlying signaling pathways insights of CR has yet to be elucidated.
METHODS
In the present study, a quantitative approach with tandem mass tag (TMT) labeling and liquid chromatography-tandem mass spectrometry was used to characterize the differential protein expression profiles of patients with CR. Plasma samples were collected from patients with CR (n = 37), patients with AMI (n = 47), and healthy controls (n = 47). Candidate proteins were selected for validation by multiple reaction monitoring (MRM) and enzyme-linked immunosorbent assay (ELISA).
RESULTS
In total, 1208 proteins were quantified and 958 differentially expressed proteins (DEPs) were identified. The difference in the expression levels of the DEPs was more noticeable between the CR and Con groups than between the AMI and Con groups. Bioinformatics analysis showed most of the DEPs to be involved in numerous crucial biological processes and signaling pathways, such as RNA transport, ribosome, proteasome, and protein processing in the endoplasmic reticulum, as well as necroptosis and leukocyte transendothelial migration, which might play essential roles in the complex pathological processes associated with CR. MRM analysis confirmed the accuracy of the proteomic analysis results. Four proteins i.e., C-reactive protein (CRP), heat shock protein beta-1 (HSPB1), vinculin (VINC) and growth/differentiation factor 15 (GDF15), were further validated via ELISA. By receiver operating characteristic (ROC) analysis, combinations of these four proteins distinguished CR patients from AMI patients with a high area under the curve (AUC) value (0.895, 95% CI, 0.802-0.988, p < 0.001).
CONCLUSIONS
Our study highlights the value of comprehensive proteomic characterization for identifying plasma proteome changes in patients with CR. This pilot study could serve as a valid foundation and initiation point for elucidation of the mechanisms of CR, which might aid in identifying effective diagnostic biomarkers in the future.
PubMed: 38429673
DOI: 10.1186/s12014-024-09474-9 -
Materials Today. Bio Dec 2023Bone resident cells are constantly subjected to a range of distinct mechanical loadings, which generates a complex microenvironment. In particular, hydrostatic pressure...
Bone resident cells are constantly subjected to a range of distinct mechanical loadings, which generates a complex microenvironment. In particular, hydrostatic pressure (HP) has a key impact on modulation of cell function and fate determination. Although HP is a constant mechanical stimulus, its role in regulating the osteogenesis process within a defined 3D microenvironment has not been comprehensively elucidated. Perceiving how environmental factors regulate the differentiation of stem cells is essential for expanding their regenerative potential. Inspired by the mechanical environment of bone, this study attempted to investigate the influence of different ranges of cyclic HP on human adipose-derived mesenchymal stem cells (MSCs) encapsulated within a compartmentalized liquefied microenvironment. Taking advantage of the liquefied environment of microcapsules, MSCs were exposed to cyclic HP of 5 or 50 MPa, 3 times/week at 37 °C. Biological tests using fluorescence staining of F-actin filaments showed a noticeable improvement in cell-cell interactions and cellular network formation of MSCs. These observations were more pronounced in osteogenic (OST) condition, as confirmed by fluorescent staining of vinculin. More interestingly, there was a significant increase in alkaline phosphatase activity of MSCs exposed to 50 MPa magnitude of HP, even in the absence of osteoinductive factors. In addition, a greater staining area of both osteopontin and hydroxyapatite was detected in the 50 MPa/OST group. These findings highlight the benefit of hydrostatic pressure to regulate osteogenesis of MSCs as well as the importance of employing simultaneous biochemical and mechanical stimulation to accelerate the osteogenic potential of MSCs for biomedical purposes.
PubMed: 38058695
DOI: 10.1016/j.mtbio.2023.100861 -
Cancers Apr 2024Colorectal tumorigenesis involves the development of aberrant crypt foci (ACF) or preneoplastic lesions, representing the earliest morphological lesion visible in colon...
Colorectal tumorigenesis involves the development of aberrant crypt foci (ACF) or preneoplastic lesions, representing the earliest morphological lesion visible in colon cancer. The purpose of this study was to determine changes in protein expression in carcinogen-induced ACF as they mature and transform into adenomas. Protein expression profiles of azoxymethane (AOM)-induced F344 rat colon ACF and adenomas were compared at four time points, 4 (control), 8, 16, and 24 weeks post AOM administration ( = 9/group), with time points correlating with induction and transformation events. At each time point, micro-dissected ACF and/or adenoma tissues were analyzed across multiple quantitative two-dimensional (2D-DIGE) gels using a Cy-dye labeling technique and a pooled internal standard to quantify expression changes with statistical confidence. Western blot and subsequent network pathway mapping were used to confirm and elucidate differentially expressed ( ≤ 0.05) proteins, including changes in vinculin (; = 0.007), scinderin (; = 0.02), and profilin (; = 0.01), By determining protein expression changes in ACF as they mature and transform into adenomas, a "baseline" of altered regulatory proteins associated with adenocarcinoma development in this model has been elucidated. These data will enable future studies aimed at biomarker identification and understanding the molecular biology of intestinal tumorigenesis and adenocarcinoma maturation under varying intestinal conditions.
PubMed: 38730628
DOI: 10.3390/cancers16091678 -
Chinese Herbal Medicines Jan 2024This study is designed to investigate the mode of action of the synergistic effect of 5-fluorouracil (5-FU) and magnolol against cervical cancer.
OBJECTIVE
This study is designed to investigate the mode of action of the synergistic effect of 5-fluorouracil (5-FU) and magnolol against cervical cancer.
METHODS
Network pharmacological approach was applied to predict the molecular mechanism of 5-FU combined with magnolol against cervical cancer. CCK-8 assay, colony formation assay, immunofluorescence staining, adhesion assay, wound healing mobility assay, cell migration and invasion assay and Western blot analysis were conducted to validate the results of study.
RESULTS
Phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway was identified as the key pathway study. The experimental results showed that 5-FU combined with magnolol strongly inhibited cervical cancer cell proliferation, induced the morphological change of HeLa cells by down-regulating the expression of -actinin, tensin-2 and vinculin. Moreover, magnolol enhanced inhibitory effect of 5-FU on the cell adhesion, migration and invasion. The phosphorylation of AKT and PI3K and the expression of mTOR were strongly inhibited by the combination of 5-FU and magnolol. Moreover, the expression of E-cadherin and -catenin was upregulated and the expression of Snail, Slug and vimentin was down-regulated by the 5-FU together with magnolol.
CONCLUSION
Taken together, this study suggests that 5-FU combined with magnolol exerts a synergistic anti-cervical cancer effect by regulating the PI3K/AKT/mTOR and epithelial-mesenchymal transition (EMT) signaling pathways.
PubMed: 38375055
DOI: 10.1016/j.chmed.2023.01.004 -
Biomedicines Feb 2024Prognoses for TNBC remain poor due to its aggressive nature and the lack of therapies that target its "drivers". RASA1, a RAS-GAP or GTPase-activating protein whose...
Prognoses for TNBC remain poor due to its aggressive nature and the lack of therapies that target its "drivers". RASA1, a RAS-GAP or GTPase-activating protein whose activity inhibits RAS signaling, is downregulated in up to 77% of TNBC cases. As such, RAS proteins become hyperactive and similar in effect to mutant hyperactive RAS proteins with impaired GTPase activities. PCAIs are a novel class of agents designed to target and disrupt the activities of KRAS and other G-proteins that are hyperactive in various cancers. This study shows the anticancer mechanisms of the PCAIs in two breast cancer cell lines, MDA-MB-468 and MDA-MB-231. PCAIs (NSL-YHJ-2-27) treatment increased BRAF phosphorylation, whereas CRAF phosphorylation significantly decreased in both cell lines. Moreover, the PCAIs also stimulated the phosphorylation of MEK, ERK, and p90RSK by 116, 340, and 240% in MDA-MB-468 cells, respectively. However, in MDA-MB-231 cells, a significant increase of 105% was observed only in p90RSK phosphorylation. Opposing effects were observed for AKT phosphorylation, whereby an increase was detected in MDA-MB-468 cells and a decrease in MDA-MB-231 cells. The PCAIs also induced apoptosis, as observed in the increased pro-apoptotic protein BAK1, by 51%, after treatment. The proportion of live cells in PCAIs-treated spheroids decreased by 42 and 34% in MDA-MB-468 and MDA-MB-231 cells, respectively, which further explains the PCAIs-induced apoptosis. The movement of the cells through the Matrigel was also inhibited by 74% after PCAIs exposure, which could have been due to the depleted levels of F-actin and vinculin punctate, resulting in the shrinkage of the cells by 76%, thereby impeding cell movement. These results show promise for PCAIs as potential therapies for TNBC as they significantly inhibit the hallmark processes and pathways that promote cell proliferation, migration, and invasion, which result in poor prognoses for breast cancer patients.
PubMed: 38540084
DOI: 10.3390/biomedicines12030470