Publications
83 results found
Yaganoglu S, Kalyviotis K, Vagena-Pantoula C, et al., 2023, Author Correction: Highly specific and non-invasive imaging of Piezo1-dependent activity across scales using GenEPi, Nature Communications, Vol: 14, ISSN: 2041-1723
Pantazis P, Pantazis P, Yaganoglu S, et al., 2023, Highly specific and non-invasive imaging of Piezo1-dependent activity across scales using GenEPi, Nature Communications, Vol: 14, Pages: 1-16, ISSN: 2041-1723
Mechanosensing is a ubiquitous process to translate external mechanical stimuliinto biological responses. Piezo1 ion channels are directly gated by mechanical forces and playan essential role in cellular mechanotransduction. However, readouts of Piezo1 activity aremainly examined by invasive or indirect techniques, such as electrophysiological analyses andcytosolic calcium imaging. Here, we introduce GenEPi, a genetically-encoded fluorescentreporter for non-invasive optical monitoring of Piezo1-dependent activity. We demonstrate thatGenEPi has high spatiotemporal resolution for Piezo1-dependent stimuli from the single-celllevel to that of the entire organism. GenEPi reveals transient, local mechanical stimuli in theplasma membrane of single cells, resolves repetitive contraction-triggered stimulation ofbeating cardiomyocytes within microtissues, and allows for robust and reliable monitoring of Piezo1-dependent activity in vivo. GenEPi will enable non-invasive optical monitoring ofPiezo1 activity in mechanochemical feedback loops during development, homeostaticregulation, and disease.
Matellan C, Lachowski D, Cortes E, et al., 2023, Retinoic acid receptor β modulates mechanosensing and invasion in pancreatic cancer cells via myosin light chain 2, Oncogenesis, Vol: 12, Pages: 1-11, ISSN: 2157-9024
Pancreatic ductal adenocarcinoma (PDAC) is the most common and lethal form of pancreatic cancer, characterised by stromal remodelling, elevated matrix stiffness and high metastatic rate. Retinoids, compounds derived from vitamin A, have a history of clinical use in cancer for their anti-proliferative and differentiation effects, and more recently have been explored as anti-stromal therapies in PDAC for their ability to induce mechanical quiescence in cancer associated fibroblasts. Here, we demonstrate that retinoic acid receptor β (RAR-β) transcriptionally represses myosin light chain 2 (MLC-2) expression in pancreatic cancer cells. As a key regulatory component of the contractile actomyosin machinery, MLC-2 downregulation results in decreased cytoskeletal stiffness and traction force generation, impaired response to mechanical stimuli via mechanosensing and reduced ability to invade through the basement membrane. This work highlights the potential of retinoids to target the mechanical drivers of pancreatic cancer.
Peng L, Matellan C, Bosch-Fortea M, et al., 2023, Mesenchymal Stem Cells Sense the Toughness of Nanomaterials and Interfaces, ADVANCED HEALTHCARE MATERIALS, Vol: 12, ISSN: 2192-2640
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Blackford SJI, Yu TTL, Norman MDA, et al., 2023, RGD density along with substrate stiffness regulate hPSC hepatocyte functionality through YAP signalling, Biomaterials, Vol: 293, Pages: 1-17, ISSN: 0142-9612
Human pluripotent stem cell-derived hepatocytes (hPSC-Heps) may be suitable for treating liver diseases, but differentiation protocols often fail to yield adult-like cells. We hypothesised that replicating healthy liver niche biochemical and biophysical cues would produce hepatocytes with desired metabolic functionality. Using 2D synthetic hydrogels which independently control mechanical properties and biochemical cues, we found that culturing hPSC-Heps on surfaces matching the stiffness of fibrotic liver tissue upregulated expression of genes for RGD-binding integrins, and increased expression of YAP/TAZ and their transcriptional targets. Alternatively, culture on soft, healthy liver-like substrates drove increases in cytochrome p450 activity and ureagenesis. Knockdown of ITGB1 or reducing RGD-motif-containing peptide concentration in stiff hydrogels reduced YAP activity and improved metabolic functionality; however, on soft substrates, reducing RGD concentration had the opposite effect. Furthermore, targeting YAP activity with verteporfin or forskolin increased cytochrome p450 activity, with forskolin dramatically enhancing urea synthesis. hPSC-Heps could also be successfully encapsulated within RGD peptide-containing hydrogels without negatively impacting hepatic functionality, and compared to 2D cultures, 3D cultured hPSC-Heps secreted significantly less fetal liver-associated alpha-fetoprotein, suggesting furthered differentiation. Our platform overcomes technical hurdles in replicating the liver niche, and allowed us to identify a role for YAP/TAZ-mediated mechanosensing in hPSC-Hep differentiation.
Majkowska A, Inostroza-Brito KE, Gonzalez M, et al., 2023, Peptide-Protein Coassemblies into Hierarchical and Bioactive Tubular Membranes, BIOMACROMOLECULES, Vol: 24, Pages: 4419-4429, ISSN: 1525-7797
Kong D, Peng L, Bosch-Fortea M, et al., 2022, Impact of the multiscale viscoelasticity of quasi-2D self-assembled protein networks on stem cell expansion at liquid interfaces, Biomaterials, Vol: 284, Pages: 121494-121494, ISSN: 0142-9612
Although not typically thought to sustain cell adhesion and expansion, liquid substrates have recently been shown to support such phenotypes, providing protein nanosheets could be assembled at corresponding liquid-liquid interfaces. However, the precise mechanical properties required from such quasi-2D nanoassemblies and how these correlate with molecular structure and nanoscale architecture has remained unclear. In this report, we screen a broad range of surfactants, proteins, oils and cell types and correlate interfacial mechanical properties with stem cell expansion. Correlations suggest an impact of interfacial viscoelasticity on the regulation of such behaviour. We combine interfacial rheology and magnetic tweezer-based interfacial microrheology to characterise the viscoelastic profile of protein nanosheets assembled at liquid-liquid interfaces. Based on neutron reflectometry and transmission electron microscopy data, we propose that the amorphous nanoarchitecture of quasi-2D protein nanosheets controls their multi-scale viscoelasticity which, in turn, correlates with cell expansion. This understanding paves the way for the rational design of protein nanosheets for microdroplet and bioemulsion-based stem cell manufacturing and screening platforms.
Lachowski D, Matellan C, Gopal S, et al., 2022, Substrate stiffness-driven membrane tension modulates vesicular trafficking via caveolin-1., ACS Nano, Vol: 16, Pages: 4322-4337, ISSN: 1936-0851
Liver fibrosis, a condition characterized by extensive deposition and cross-linking of extracellular matrix (ECM) proteins, is idiosyncratic in cases of chronic liver injury. The dysregulation of ECM remodeling by hepatic stellate cells (HSCs), the main mediators of fibrosis, results in an elevated ECM stiffness that drives the development of chronic liver disease such as cirrhosis and hepatocellular carcinoma. Tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) is a key element in the regulation of ECM remodeling, which modulates the degradation and turnover of ECM components. We have previously reported that a rigid, fibrotic-like substrate can impact TIMP-1 expression at the protein level in HSCs without altering its mRNA expression. While HSCs are known to be highly susceptible to mechanical stimuli, the mechanisms through which mechanical cues regulate TIMP-1 at the post-translational level remain unclear. Here, we show a mechanism of regulation of plasma membrane tension by matrix stiffness. We found that this effect is orchestrated by the β1 integrin/RhoA axis and results in elevated exocytosis and secretion of TIMP-1 in a caveolin-1- and dynamin-2-dependent manner. We then show that TIMP-1 and caveolin-1 expression increases in cirrhosis and hepatocellular carcinoma. These conditions are associated with fibrosis, and this effect can be recapitulated in 3D fibrosis models consisting of hepatic stellate cells encapsulated in a self-assembling polypeptide hydrogel. This work positions stiffness-dependent membrane tension as a key regulator of enzyme secretion and function and a potential target for therapeutic strategies that aim at modulating ECM remodeling in chronic liver disease.
Keen AN, Payne LA, Mehta V, et al., 2022, Eukaryotic initiation factor 6 regulates mechanical responses in endothelial cells, Journal of Cellular Biochemistry, Vol: 221, ISSN: 0730-2312
The repertoire of extratranslational functions of components of the protein synthesis apparatus is expanding to include control of key cell signaling networks. However, very little is known about noncanonical functions of members of the protein synthesis machinery in regulating cellular mechanics. We demonstrate that the eukaryotic initiation factor 6 (eIF6) modulates cellular mechanobiology. eIF6-depleted endothelial cells, under basal conditions, exhibit unchanged nascent protein synthesis, polysome profiles, and cytoskeleton protein expression, with minimal effects on ribosomal biogenesis. In contrast, using traction force and atomic force microscopy, we show that loss of eIF6 leads to reduced stiffness and force generation accompanied by cytoskeletal and focal adhesion defects. Mechanistically, we show that eIF6 is required for the correct spatial mechanoactivation of ERK1/2 via stabilization of an eIF6-RACK1-ERK1/2-FAK mechanocomplex, which is necessary for force-induced remodeling. These results reveal an extratranslational function for eIF6 and a novel paradigm for how mechanotransduction, the cellular cytoskeleton, and protein translation constituents are linked.
Lachowski D, Matellan C, Cortes E, et al., 2021, Self-assembling polypeptide hydrogels as a platform to recapitulate the tumor microenvironment, Cancers, Vol: 13, Pages: 1-25, ISSN: 2072-6694
The tumor microenvironment plays a critical role in modulating cancer cell migration, metabolism, and malignancy, thus, highlighting the need to develop in vitro culture systems that can recapitulate its abnormal properties. While a variety of stiffness-tunable biomaterials, reviewed here, have been developed to mimic the rigidity of the tumor extracellular matrix, culture systems that can recapitulate the broader extracellular context of the tumor microenvironment (including pH and temperature) remain comparably unexplored, partially due to the difficulty in independently tuning these parameters. Here, we investigate a self-assembled polypeptide network hydrogel as a cell culture platform and demonstrate that the culture parameters, including the substrate stiffness, extracellular pH and temperature, can be independently controlled. We then use this biomaterial as a cell culture substrate to assess the effect of stiffness, pH and temperature on Suit2 cells, a pancreatic cancer cell line, and demonstrate that these microenvironmental factors can regulate two critical transcription factors in cancer: yes-associated protein 1 (YAP) and hypoxia inducible factor (HIF-1A).
Julian L, Naylor G, Wickman GR, et al., 2021, Defective apoptotic cell contractility provokes sterile inflammation, leading to liver damage and tumour suppression, eLife, Vol: 10, Pages: 1-32, ISSN: 2050-084X
Apoptosis is characterized by profound morphological changes, but their physiological purpose is unknown. To characterize the role of apoptotic cell contraction, ROCK1 was rendered caspase non-cleavable (ROCK1nc) by mutating aspartate 1113, which revealed that ROCK1 cleavage was necessary for forceful contraction and membrane blebbing. When homozygous ROCK1nc mice were treated with the liver-selective apoptotic stimulus of diethylnitrosamine, ROCK1nc mice had more profound liver damage with greater neutrophil infiltration than wild-type mice. Inhibition of the damage-associated molecular pattern protein HMGB1 or signalling by its cognate receptor TLR4 lowered neutrophil infiltration and reduced liver damage. ROCK1nc mice also developed fewer diethylnitrosamine-induced hepatocellular carcinoma (HCC) tumours, while HMGB1 inhibition increased HCC tumour numbers. Thus, ROCK1 activation and consequent cell contraction are required to limit sterile inflammation and damage amplification following tissue-scale cell death. Additionally, these findings reveal a previously unappreciated role for acute sterile inflammation as an efficient tumour-suppressive mechanism.
Cheong SS, Akram K, Metellan C, et al., 2020, The planar polarity component Vangl2 is a key regulator of mechanosignaling, Frontiers in Cell and Developmental Biology, Vol: 8, ISSN: 2296-634X
VANGL2 is a component of the planar cell polarity (PCP) pathway, which regulates tissue polarity and patterning. The Vangl2Lp mutation causes lung branching defects due to dysfunctional actomyosin-driven morphogenesis. Since the actomyosin network regulates cell mechanics, we speculated that mechanosignaling could be impaired when VANGL2 is disrupted. Here, we used live-imaging of precision-cut lung slices (PCLS) from Vangl2Lp/+ mice to determine that alveologenesis is attenuated as a result of impaired epithelial cell migration. Vangl2Lp/+ tracheal epithelial cells (TECs) and alveolar epithelial cells (AECs) exhibited highly disrupted actomyosin networks and focal adhesions (FAs). Functional assessment of cellular forces confirmed impaired traction force generation in Vangl2Lp/+ TECs. YAP signaling in Vangl2Lp airway epithelium was reduced, consistent with a role for VANGL2 in mechanotransduction. Furthermore, activation of RhoA signaling restored actomyosin organization in Vangl2Lp/+, confirming RhoA as an effector of VANGL2. This study identifies a pivotal role for VANGL2 in mechanosignaling, which underlies the key role of the PCP pathway in tissue morphogenesis.
Lachowski D, Cortes Lopez J, Matellan C, et al., 2020, G protein-coupled estrogen receptor regulates actin cytoskeleton dynamics to impair cell polarization, Frontiers in Cell and Developmental Biology, Vol: 8, ISSN: 2296-634X
Mechanical forces regulate cell functions through multiple pathways. G protein-coupled estrogen receptor (GPER) is a seven-transmembrane receptor that is ubiquitously expressed across tissues and mediates the acute cellular response to estrogens. Here, we demonstrate an unidentified role of GPER as a cellular mechanoregulator. G protein-coupled estrogen receptor signaling controls the assembly of stress fibers, the dynamics of the associated focal adhesions, and cell polarization via RhoA GTPase (RhoA). G protein-coupled estrogen receptor activation inhibits F-actin polymerization and subsequently triggers a negative feedback that transcriptionally suppresses the expression of monomeric G-actin. Given the broad expression of GPER and the range of cytoskeletal changes modulated by this receptor, our findings position GPER as a key player in mechanotransduction.
Lachowski D, Cortes Lopez J, Matellan C, et al., 2020, GPER regulates actin cytoskeleton dynamics to impair cell polarization, Frontiers in Cell and Developmental Biology, Vol: 8, ISSN: 2296-634X
Mechanical forces regulate cell functions through multiple pathways. G protein-coupled estrogen receptor (GPER) is a seven-transmembrane receptor that is ubiquitously expressed across tissues and mediates the acute cellular response to estrogens. Here, we demonstrate an unidentified role of GPER as a cellular mechanoregulator.G protein-coupled estrogen receptor signaling controls the assembly of stress fibers, the dynamics of the associated focal adhesions, and cell polarization via RhoA GTPase (RhoA). G protein-coupled estrogen receptor activation inhibits F-actin polymerization and subsequently triggers a negative feedback that transcriptionally suppresses the expression of monomeric G-actin. Given the broad expression of GPER and the range of cytoskeletal changes modulated by this receptor, our findings position GPER as a key player in mechanotransduction.
Majkowska A, Redondo-Gomez C, Rice A, et al., 2020, Interfacial self-assembly to spatially organize graphene oxide into hierarchical and bioactive structures, Frontiers in Materials, Vol: 7, Pages: 1-13, ISSN: 2296-8016
Multicomponent self-assembly holds great promise for the generation of complex and functional biomaterials with hierarchical microstructure. Here, we describe the use of supramolecular co-assembly between an elastin-like recombinamer (ELR5) and a peptide amphiphile (PA) to organize graphene oxide (GO) flakes into bioactive structures across multiple scales. The process takes advantage of a reaction—diffusion mechanism to enable the incorporation and spatial organization of GO within multiple ELR5/PA layers. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ImageJ software were used to demonstrate the hierarchical organization of GO flakes within the ELR5/PA layers and the distribution profiles of GO throughout the ELR5/PA membranes. Furthermore, atomic force microscopy (AFM) revealed improved Young's Moduli of the ELR5/PA/GO membranes compared to the ELR5/PA membranes. Lastly, we investigated biocompatibility of the ELR5/PA/GO membrane via various cell culture methods.
Chronopoulos A, Thorpe SD, Cortes E, et al., 2020, Syndecan-4 tunes cell mechanics by activating the kindlin-integrin-RhoA pathway, Nature Materials, Vol: 19, Pages: 669-678, ISSN: 1476-1122
Extensive research over the past decades has identified integrins to be the primary transmembrane receptors that enable cells to respond to external mechanical cues. We reveal here a mechanism whereby syndecan-4 tunes cell mechanics in response to localized tension via a coordinated mechanochemical signalling response that involves activation of two other receptors: epidermal growth factor receptor and β1 integrin. Tension on syndecan-4 induces cell-wide activation of the kindlin-2/β1 integrin/RhoA axis in a PI3K-dependent manner. Furthermore, syndecan-4-mediated tension at the cell–extracellular matrix interface is required for yes-associated protein activation. Extracellular tension on syndecan-4 triggers a conformational change in the cytoplasmic domain, the variable region of which is indispensable for the mechanical adaptation to force, facilitating the assembly of a syndecan-4/α-actinin/F-actin molecular scaffold at the bead adhesion. This mechanotransduction pathway for syndecan-4 should have immediate implications for the broader field of mechanobiology.
Mehta V, Pang K-L, Rozbesky D, et al., 2020, The guidance receptor plexin D1 is a mechanosensor in endothelial cells, Nature, Vol: 578, Pages: 290-295, ISSN: 0028-0836
Shear stress on arteries produced by blood flow is important for vascular development and homeostasis but can also initiate atherosclerosis1. Endothelial cells that line the vasculature use molecular mechanosensors to directly detect shear stress profiles that will ultimately lead to atheroprotective or atherogenic responses2. Plexins are key cell-surface receptors of the semaphorin family of cell-guidance signalling proteins and can regulate cellular patterning by modulating the cytoskeleton and focal adhesion structures3,4,5. However, a role for plexin proteins in mechanotransduction has not been examined. Here we show that plexin D1 (PLXND1) has a role in mechanosensation and mechanically induced disease pathogenesis. PLXND1 is required for the response of endothelial cells to shear stress in vitro and in vivo and regulates the site-specific distribution of atherosclerotic lesions. In endothelial cells, PLXND1 is a direct force sensor and forms a mechanocomplex with neuropilin-1 and VEGFR2 that is necessary and sufficient for conferring mechanosensitivity upstream of the junctional complex and integrins. PLXND1 achieves its binary functions as either a ligand or a force receptor by adopting two distinct molecular conformations. Our results establish a previously undescribed mechanosensor in endothelial cells that regulates cardiovascular pathophysiology, and provide a mechanism by which a single receptor can exhibit a binary biochemical nature.
Rice A, Cortes Lopez JE, Lachowski D, et al., 2020, GPER activation inhibits cancer cell mechanotransduction and basement membrane invasion via RhoA, Cancers, Vol: 12, ISSN: 2072-6694
The invasive properties of cancer cells are intimately linked to their mechanical phenotype, which can be regulated by intracellular biochemical signalling. Cell contractility, induced by mechanotransduction of a stiff fibrotic matrix, and the epithelial–mesenchymal transition (EMT) promote invasion. Metastasis involves cells pushing through the basement membrane into the stroma—both of which are altered in composition with cancer progression. Agonists of the G protein-coupled oestrogen receptor (GPER), such as tamoxifen, have been largely used in the clinic, and interest in GPER, which is abundantly expressed in tissues, has greatly increased despite a lack of understanding regarding the mechanisms which promote its multiple effects. Here, we show that specific activation of GPER inhibits EMT, mechanotransduction and cell contractility in cancer cells via the GTPase Ras homolog family member A (RhoA). We further show that GPER activation inhibits invasion through an in vitro basement membrane mimic, similar in structure to the pancreatic basement membrane that we reveal as an asymmetric bilayer, which differs in composition between healthy and cancer patients.Keywords: cancer biomechanics; metastasis; G protein-coupled receptors; tumour microenvironment
Ghose R, Rice AJ, Cortes E, et al., 2020, Implementation of a basement membrane invasion assay using mesenteric tissue, CELL-DERIVED MATRICES, PT B, Editors: Caballero, Kundu, Reis, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 99-122
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Rice A, Hernandez ADR, 2020, Biomechanics of cancer cells, BIOENGINEERING INNOVATIVE SOLUTIONS FOR CANCER, Editors: Ladame, Chang, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 327-361, ISBN: 978-0-12-813886-1
Mazza G, Telese A, Al-Akkad W, et al., 2019, Cirrhotic human liver extracellular matrix 3D scaffolds promote smad-dependent TGF-β1 epithelial mesenchymal transition, Cells, Vol: 9, Pages: 1-16, ISSN: 2073-4409
An altered liver microenvironment characterized by a dysregulated extracellular matrix (ECM) supports the development and progression of hepatocellular carcinoma (HCC). The development of experimental platforms able to reproduce these physio-pathological conditions is essential in order to identify and validate new therapeutic targets for HCC. The aim of this work was to validate a new in vitro model based on engineering three-dimensional (3D) healthy and cirrhotic human liver scaffolds with HCC cells recreating the micro-environmental features favoring HCC. Healthy and cirrhotic human livers ECM scaffolds were developed using a high shear stress oscillation-decellularization procedure. The scaffolds bio-physical/bio-chemical properties were analyzed by qualitative and quantitative approaches. Cirrhotic 3D scaffolds were characterized by biomechanical properties and microarchitecture typical of the native cirrhotic tissue. Proteomic analysis was employed on decellularized 3D scaffolds and showed specific enriched proteins in cirrhotic ECM in comparison to healthy ECM proteins. Cell repopulation of cirrhotic scaffolds highlighted a unique up-regulation in genes related to epithelial to mesenchymal transition (EMT) and TGFβ signaling. This was also supported by the presence and release of higher concentration of endogenous TGFβ1 in cirrhotic scaffolds in comparison to healthy scaffolds. Fibronectin secretion was significantly upregulated in cells grown in cirrhotic scaffolds in comparison to cells engrafted in healthy scaffolds. TGFβ1 induced the phosphorylation of canonical proteins Smad2/3, which was ECM scaffold-dependent. Important, TGFβ1-induced phosphorylation of Smad2/3 was significantly reduced and ECM scaffold-independent when pre/simultaneously treated with the TGFβ-R1 kinase inhibitor Galunisertib. In conclusion, the inherent features of cirrhotic human liver ECM micro-environment were dissected and characterized for the first time
Kwong Hong Tsang D, Lieberthal T, Watts C, et al., 2019, Chemically functionalised graphene FET biosensor for the label-free sensing of exosomes, Scientific Reports, Vol: 9, ISSN: 2045-2322
A graphene field-effect transistor (gFET) was non-covalently functionalised with 1-pyrenebutyric acid N-hydroxysuccinimide ester and conjugated with anti-CD63 antibodiesfor the label-free detection of exosomes.Using a microfluidic channel, part of a graphene film was exposed to solution. The change in electrical properties of the exposed graphene created anadditional minimum alongside the original Dirac point inthe drain-source current(Ids)-back-gate voltage (Vg) curve. When phosphate buffered saline (PBS) was present in the channel, the additional minimum was present at a Vglower than the original Dirac point and shifted with time when exosomes were introduced into the channel.Thisshift of the minimum from the PBS reference point reached saturationafter 30 minutesand was observed for multiple exosome concentrations. Upon conjugation with an isotype control, sensor responsetothe highest concentration ofexosomes was negligible in comparison to that with anti-CD63antibody, indicatingthat thefunctionalised gFETcan specifically detect exosomes at least down to 0.1μg/mLand is sensitive to concentration. Such a gFET biosensor has not been used before for exosome sensing and could be an effective tool for the liquid-biopsy detection of exosomes as biomarkers for early-stage identification of diseases such as cancer.
Rice A, Del Rio Hernandez A, 2019, The mutational landscape of pancreatic and liver cancer, as represented by circulating tumour DNA, Frontiers in Oncology, Vol: 9, ISSN: 2234-943X
The mutational landscapes of pancreatic and liver cancer share many common genetic alterations which drive cancer progression.However, these mutations do not occur in all cases of these diseases, and this tumoural heterogeneity impedes diagnosis,prognosis and therapeutic development. One minimally invasive method for the evaluation of tumour mutations is the analysis ofcirculating tumour DNA (ctDNA), released through apoptosis, necrosis and active secretion by tumour cells into various body fluids.By observing mutations in those genes which promote transformation by controlling the cell cycle and oncogenic signallingpathways, a representation of the mutational profile of the tumour is revealed. The analysis of ctDNA is a promising technique forinvestigating these two gastrointestinal cancers, as many studies have reported on the accuracy of ctDNA assessment fordiagnosis and prognosis using a variety of techniques.
Perone Y, Farrugia AJ, Rodriguez-Meira A, et al., 2019, Author Corrections: SREBP1 drives keratin-80-dependent cytoskeletal changes and invasive behavior in endocrine-resistant ER alpha breast cancer, Nature Communications, Vol: 10, ISSN: 2041-1723
Matellan C, Del Río Hernández AE, 2019, Where no hand has gone before: probing mechanobiology at the cellular level., ACS Biomaterials Science and Engineering, Vol: 5, Pages: 3703-3719, ISSN: 2373-9878
Physical forces and other mechanical stimuli are fundamental regulators of cell behavior and function. Cells are also biomechanically competent: they generate forces to migrate, contract, remodel, and sense their environment. As the knowledge of the mechanisms of mechanobiology increases, the need to resolve and probe increasingly small scales calls for novel technologies to mechanically manipulate cells, examine forces exerted by cells, and characterize cellular biomechanics. Here, we review novel methods to quantify cellular force generation, measure cell mechanical properties, and exert localized piconewton and nanonewton forces on cells, receptors, and proteins. The combination of these technologies will provide further insight on the effect of mechanical stimuli on cells and the mechanisms that convert these stimuli into biochemical and biomechanical activity.
Lachowski D, Cortes E, Rice A, et al., 2019, Matrix stiffness modulates the activity of MMP-9 and TIMP-1 in hepatic stellate cells to perpetuate fibrosis, Scientific Reports, Vol: 9, ISSN: 2045-2322
Liver fibrosis is characterised by a dense and highly cross-linked extracellular matrix (ECM) which promotes progression of diseases such as hepatocellular carcinoma. The fibrotic microenvironment is characterised by an increased stiffness, with rigidity associated with disease progression. External stiffness is known to promote hepatic stellate cell (HSC) activation through mechanotransduction, leading to increased secretion of ECM components. HSCs are key effector cells which maintain the composition of the ECM in health and disease, not only by regulating secretion of ECM proteins such as collagen, but also ECM-degrading enzymes called matrix metalloproteinases (MMPs) and their inhibitors (TIMPs). Uninhibited MMPs degrade ECM proteins to reduce external rigidity. Using fibronectin-coated polyacrylamide gels to alter substrate rigidity without altering ligand density, we show that fibrotic rigidities downregulate MMP-9 expression and secretion, and also upregulate secretion of TIMP-1, though not its expression. Using tissue immunofluorescence studies, we also report that the expression of MMP-9 is significantly decreased in activated HSCs in fibrotic tissues associated with hepatocellular carcinoma. This suggests the presence of a mechanical network that allows HSCs to maintain a fibrotic ECM, with external rigidity providing feedback which affects MMP-9 and TIMP-1 secretion, which may become dysregulated in fibrosis.
Perone Y, Farrugia AJ, Meira AR, et al., 2019, SREBP1 drives Keratin 80-dependent cytoskeletal changes and invasive behavior in endocrine resistant ERα breast cancer, Nature Communications, Vol: 10, ISSN: 2041-1723
Approximately 30% of ERα breast cancer patients relapse with metastatic disease following adjuvant endocrine therapies. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain undergoes epigenetic reprogramming in aromatase inhibitors (AI)-resistant cells, leading to Keratin-80 (KRT80) upregulation. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 1 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion and cellular stiffening, collectively promoting cancer cell invasion. Shearwave elasticity imaging performed on prospectively recruited patients confirms KRT80 levels correlate with stiffer tumors. Immunohistochemistry showed increased KRT80-positive cells at relapse and, using several clinical endpoints, KRT80 expression associates with poor survival. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment.
Matellan C, Del Río Hernández AE, 2019, Engineering the cellular mechanical microenvironment - from bulk mechanics to the nanoscale., J Cell Sci, Vol: 132
The field of mechanobiology studies how mechanical properties of the extracellular matrix (ECM), such as stiffness, and other mechanical stimuli regulate cell behaviour. Recent advancements in the field and the development of novel biomaterials and nanofabrication techniques have enabled researchers to recapitulate the mechanical properties of the microenvironment with an increasing degree of complexity on more biologically relevant dimensions and time scales. In this Review, we discuss different strategies to engineer substrates that mimic the mechanical properties of the ECM and outline how these substrates have been applied to gain further insight into the biomechanical interaction between the cell and its microenvironment.
Cortes E, Lachowski D, Rice A, et al., 2019, Retinoic acid receptor-β is downregulated in hepatocellular carcinoma and cirrhosis and its expression inhibits myosin-driven activation and durotaxis in hepatic stellate cells, Hepatology, Vol: 69, Pages: 785-802, ISSN: 0270-9139
Hepatic stellate cells (HSCs) are essential perisinusoidal cells in the healthy and diseased liver. HSCs modulate extracellular matrix (ECM) homeostasis when quiescent, but in liver fibrosis, HSCs become activated and promote excess deposition of ECM molecules and tissue stiffening via force generation and mechanosensing. In hepatocellular carcinoma (HCC), activated HSCs infiltrate the stroma and migrate to the tumor core to facilitate paracrine signalling with cancer cells. Since the function of HSCs is known to be modulated by retinoids, we investigated the expression profile of retinoic acid receptor beta (RAR-β) in cirrhotic and HCC patients, as well as the effects of RAR-β activation in HSCs. We found that RAR-β expression is significantly reduced in cirrhotic and HCC tissues. Using a comprehensive set of biophysical methods combined with cellular and molecular biology, we have elucidated the biomechanical mechanism by which all trans-retinoic acid (ATRA) promotes HSC deactivation via RAR-β-dependent transcriptional downregulation of myosin light chain 2 (MLC-2) expression. Furthermore, this also abrogated mechanically driven migration towards stiffer substrates. CONCLUSION: Targeting mechanotransduction in HSCs at the transcriptional level may offer new therapeutic options for a range of liver diseases. This article is protected by copyright. All rights reserved.
Cortes E, Sarper M, Robinson B, et al., 2019, GPER is a mechanoregulator of pancreatic stellate cells and the tumor microenvironment, EMBO Reports, Vol: 20, ISSN: 1469-221X
The mechanical properties of the tumor microenvironment are emerging as attractive targets for the development of therapies. Tamoxifen, an agonist of the G protein-coupled estrogen receptor (GPER), is widely used to treat estrogen-positive breast cancer. Here, we show that tamoxifen mechanically reprograms the tumor microenvironment through a newly identified GPER-mediated mechanism. Tamoxifen inhibits the myofibroblastic differentiation of pancreatic stellate cells (PSCs) in the tumor microenvironment of pancreatic cancer in an acto-myosin-dependent manner via RhoA-mediated contractility, YAP deactivation, and GPER signaling. This hampers the ability of PSCs to remodel the extracellular matrix and to promote cancer cell invasion. Tamoxifen also reduces the recruitment and polarization to the M2 phenotype of tumor-associated macrophages. Our results highlight GPER as a mechanical regulator of the tumor microenvironment that targets the three hallmarks of pancreatic cancer: desmoplasia, inflammation, and immune suppression. The well-established safety of tamoxifen in clinics may offer the possibility to redirect the singular focus of tamoxifen on the cancer cells to the greater tumor microenvironment and lead a new strategy of drug repurposing.
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