Physicochemical interactions between the cell and its environment are crucial for morphogenesis, tissue homeostasis, remodeling and pathogenesis. Cells form specialized structures like focal adhesions and podosomes that are responsible for bi-directional information exchange between the cell and its surroundings. Besides their role in the transmission of regulatory signals, these structures are also involved in mechanosensing and mechanotransduction. In the past few years, many research groups have been trying to elucidate the mechanisms and consequences of the mechanosensitivity of cells. In this review we discuss the role of the integrin pathway in cellular mechanosensing, focusing on primary mechanosensors, molecules that respond to mechanical stress by changing their conformation. We propose mechanisms by which p130Cas is involved in this process, and emphasize the importance of mechanosensing in cell physiology and the development of diseases.
- MeSH
- Cell Surface Extensions metabolism MeSH
- Mechanotransduction, Cellular physiology MeSH
- Focal Adhesions metabolism MeSH
- Integrins metabolism MeSH
- Humans MeSH
- Stress, Mechanical MeSH
- Actin Cytoskeleton metabolism MeSH
- Crk-Associated Substrate Protein metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
CAS is a docking protein, which was shown to act as a mechanosensor in focal adhesions. The unique assembly of structural domains in CAS is important for its function as a mechanosensor. The tension within focal adhesions is transmitted to a stretchable substrate domain of CAS by focal adhesion-targeting of SH3 and CCH domain of CAS, which anchor the CAS protein in focal adhesions. Mechanistic models of the stretching biosensor propose equal roles for both anchoring domains. Using deletion mutants and domain replacements, we have analyzed the relative importance of the focal adhesion anchoring domains on CAS localization and dynamics in focal adhesions as well as on CAS-mediated mechanotransduction. We confirmed the predicted prerequisite of the focal adhesion targeting for CAS-dependent mechanosensing and unraveled the critical importance of CAS SH3 domain in mechanosensing. We further show that CAS localizes to the force transduction layer of focal adhesions and that mechanical stress stabilizes CAS in focal adhesions.
- MeSH
- Cell Adhesion MeSH
- Mechanotransduction, Cellular * MeSH
- Fibroblasts cytology metabolism MeSH
- Focal Adhesions metabolism MeSH
- Stress, Mechanical MeSH
- Mutant Proteins chemistry MeSH
- Mice MeSH
- Protein Domains MeSH
- Recombinant Fusion Proteins metabolism MeSH
- Signal Transduction MeSH
- Protein Stability MeSH
- Crk-Associated Substrate Protein chemistry metabolism MeSH
- Structure-Activity Relationship MeSH
- Green Fluorescent Proteins metabolism MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Extracellular matrix (ECM) is an essential component of the tissue microenvironment, actively shaping cellular behavior. In vitro culture systems are often poor in ECM constituents, thus not allowing for naturally occurring cell-ECM interactions. This study reports on a straightforward and efficient method for the generation of ECM scaffolds from lung tissue and its subsequent in vitro application using primary lung cells. Mouse lung tissue was subjected to decellularization with 0.2% sodium dodecyl sulfate, hypotonic solutions, and DNase. Resultant ECM scaffolds were devoid of cells and DNA, whereas lung ECM architecture of alveolar region and blood and airway networks were preserved. Scaffolds were predominantly composed of core ECM and ECM-associated proteins such as collagens I-IV, nephronectin, heparan sulfate proteoglycan core protein, and lysyl oxidase homolog 1, among others. When homogenized and applied as coating substrate, ECM supported the attachment of lung fibroblasts (LFs) in a dose-dependent manner. After ECM characterization and biocompatibility tests, a novel in vitro platform for three-dimensional (3D) matrix repopulation that permits live imaging of cell-ECM interactions was established. Using this system, LFs colonized the ECM scaffolds, displaying a close-to-native morphology in intimate interaction with the ECM fibers, and showed nuclear translocation of the mechanosensor yes-associated protein (YAP), when compared with cells cultured in two dimensions. In conclusion, we developed a 3D-like culture system, by combining an efficient decellularization method with a live-imaging culture platform, to replicate in vitro native lung cell-ECM crosstalk. This is a valuable system that can be easily applied to other organs for ECM-related drug screening, disease modeling, and basic mechanistic studies.
- MeSH
- Extracellular Matrix Proteins metabolism MeSH
- Extracellular Matrix physiology MeSH
- Fibroblasts cytology metabolism MeSH
- Cells, Cultured MeSH
- Mice, Inbred C57BL MeSH
- Mice, Inbred ICR MeSH
- Mice MeSH
- Lung cytology metabolism MeSH
- Proteomics MeSH
- In Vitro Techniques MeSH
- Tissue Engineering methods MeSH
- Tissue Scaffolds MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
RATIONALE: Cardiac ECM (extracellular matrix) comprises a dynamic molecular network providing structural support to heart tissue function. Understanding the impact of ECM remodeling on cardiac cells during heart failure (HF) is essential to prevent adverse ventricular remodeling and restore organ functionality in affected patients. OBJECTIVES: We aimed to (1) identify consistent modifications to cardiac ECM structure and mechanics that contribute to HF and (2) determine the underlying molecular mechanisms. METHODS AND RESULTS: We first performed decellularization of human and murine ECM (decellularized ECM) and then analyzed the pathological changes occurring in decellularized ECM during HF by atomic force microscopy, 2-photon microscopy, high-resolution 3-dimensional image analysis, and computational fluid dynamics simulation. We then performed molecular and functional assays in patient-derived cardiac fibroblasts based on YAP (yes-associated protein)-transcriptional enhanced associate domain (TEAD) mechanosensing activity and collagen contraction assays. The analysis of HF decellularized ECM resulting from ischemic or dilated cardiomyopathy, as well as from mouse infarcted tissue, identified a common pattern of modifications in their 3-dimensional topography. As compared with healthy heart, HF ECM exhibited aligned, flat, and compact fiber bundles, with reduced elasticity and organizational complexity. At the molecular level, RNA sequencing of HF cardiac fibroblasts highlighted the overrepresentation of dysregulated genes involved in ECM organization, or being connected to TGFβ1 (transforming growth factor β1), interleukin-1, TNF-α, and BDNF signaling pathways. Functional tests performed on HF cardiac fibroblasts pointed at mechanosensor YAP as a key player in ECM remodeling in the diseased heart via transcriptional activation of focal adhesion assembly. Finally, in vitro experiments clarified pathological cardiac ECM prevents cell homing, thus providing further hints to identify a possible window of action for cell therapy in cardiac diseases. CONCLUSIONS: Our multiparametric approach has highlighted repercussions of ECM remodeling on cell homing, cardiac fibroblast activation, and focal adhesion protein expression via hyperactivated YAP signaling during HF.
- MeSH
- Adaptor Proteins, Signal Transducing genetics metabolism MeSH
- Mechanotransduction, Cellular MeSH
- Cardiomyopathy, Dilated genetics metabolism pathology physiopathology MeSH
- Extracellular Matrix genetics metabolism ultrastructure MeSH
- Fibroblasts metabolism ultrastructure MeSH
- Ventricular Function, Left * MeSH
- Myocardial Infarction genetics metabolism pathology physiopathology MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Disease Models, Animal MeSH
- Myocardium metabolism ultrastructure MeSH
- Mice, Inbred C57BL MeSH
- Cell Movement MeSH
- Ventricular Remodeling * MeSH
- Heart Failure genetics metabolism pathology physiopathology MeSH
- Case-Control Studies MeSH
- Transcription Factors genetics metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Video-Audio Media MeSH
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Clinical studies showed that GABA(B) receptor agonists improve symptoms in patients with gastroesophageal reflux disease. One proposed mechanism of this effect is direct inhibition of the gastroesophageal vagal tension mechanosensors by GABA(B) agonists leading to reduction of reflux. In addition to tension mechanosensors, the vagal nodose ganglion supplies the esophagus with nociceptive C-fibers that likely contribute to impairment of esophageal reflex regulation in diseases. We hypothesized that GABA(B) agonists inhibit mechanically-induced activation of vagal esophageal nodose C-fibers in baseline and/or in sensitized state induced by inflammatory mediators. Ex vivo extracellular recordings were made from the esophageal nodose C-fibers in the isolated vagally-innervated guinea pig esophagus. We found that the selective GABA(B) agonist baclofen (100-300 microM) did not inhibit activation of esophageal nodose C-fibers evoked by esophageal distention (10-60 mmHg). The mechanical response of esophageal nodose C-fibers can be sensitized by different pathways including the stimulation of the histamine H(1) receptor and the stimulation the adenosine A(2A) receptor. Baclofen failed to inhibit mechanical sensitization of esophageal nodose C-fibers induced by histamine (100 microM) or the selective adenosine A(2A) receptor agonist CGS21680 (3 nM). Our data suggest that the direct mechanical inhibition of nodose C-fibers in the esophagus is unlikely to contribute to beneficial effects of GABA(B) agonists in patients with esophageal diseases.
- MeSH
- Afferent Pathways drug effects physiology MeSH
- GABA-A Receptor Agonists administration & dosage MeSH
- Baclofen administration & dosage MeSH
- Esophagus drug effects innervation physiology MeSH
- Nodose Ganglion drug effects physiology MeSH
- Guinea Pigs MeSH
- Neural Inhibition drug effects physiology MeSH
- Dose-Response Relationship, Drug MeSH
- Animals MeSH
- Check Tag
- Guinea Pigs MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Cells have developed a unique set of molecular mechanisms that allows them to probe mechanical properties of the surrounding environment. These systems are based on deformable primary mechanosensors coupled to tension transmitting proteins and enzymes generating biochemical signals. This modular setup enables to transform a mechanical load into more versatile biochemical information. Src kinase appears to be one of the central components of the mechanotransduction network mediating force-induced signalling across multiple cellular contexts. In tight cooperation with primary sensors and the cytoskeleton, Src functions as an effector molecule necessary for transformation of mechanical stimuli into biochemical outputs executing cellular response and adaptation to mechanical cues.
- MeSH
- Adaptor Proteins, Signal Transducing genetics metabolism MeSH
- Mechanotransduction, Cellular genetics MeSH
- Cytoskeleton metabolism pathology ultrastructure MeSH
- Extracellular Matrix metabolism pathology ultrastructure MeSH
- Integrins genetics metabolism MeSH
- Humans MeSH
- Stress, Mechanical MeSH
- Neoplasms genetics metabolism pathology MeSH
- Protein Serine-Threonine Kinases genetics metabolism MeSH
- Gene Expression Regulation MeSH
- src-Family Kinases genetics metabolism MeSH
- Crk-Associated Substrate Protein genetics metabolism MeSH
- Transcription Factors genetics metabolism MeSH
- Receptor-Like Protein Tyrosine Phosphatases, Class 4 genetics metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Primární řasinka je senzorická buněčná organela, která se v klidové fázi buněčného cyklu vyskytuje u většiny lidských buněk, včetně buněk embryonálních, kmenových a buněk stromatu nádoru. Přítomnost primární řasinky na povrchu buňky je přechodná: vyskytuje se v klidové G1 (G0) fázi a na počátku S fáze buněčného cyklu. Bazálním tělískem primární řasinky je mateřská centriola. U většiny nádorových buněk se primární řasinka nevyskytuje. Výjimkou jsou nádory, které jsou závislé na signální dráze Hedgehog a tím i na primární řasince, jako například bazocelulární karcinom kůže či meduloblastom. Primární řasinka je pozorována i u trojitě negativního karcinomu prsu. V primárních řasinkách je přítomna řada receptorů, včetně mechanosenzorů, receptorů pro růstové faktory (EGFR, PDGFR), hormony (somatostatin), biologicky aktivní látky (serotonin) a morfogeny (Hedgehog, Wnt). V primární řasince se vyskytují signální dráhy Hedgehog a Wnt. U těch typů lidských buněk, které mají primární řasinku – tedy u naprosté většiny buněk, se signální dráhy Hedgehog a Wnt vyskytují výlučně právě jen v primární řasince. Cílem tohoto sdělení je přehled biologických funkcí primárních řasinek.
The primary cilium is a sensory organelle protruding in the quiescent phase of the cell cycle from the surface of the majority of human cells, including embryonic cells, stem cells and stromal cells of malignant tumors. The presence of primary cilium on the cell surface is transient, limited to the quiescent G1 (G0) phase, as well as the beginning of the S phase of the cell cycle. Primary cilium is formed from the centriole. Most cancer cells do not posses the primary cilium, with some exceptions, such as tumors depending on the Hedgehog pathway -e.g. basal cell carcinoma or medulloblastoma. The primary cilium is present also in cells of triple negative breast carcinoma. Primary cilia are equiped with a variety of receptors, including mechanosensors, receptors for growth factors (EGFR, PDGFR), hormones (somatostatin), biologically active substances (serotonin) and morphogens (Hedgehog, Wnt). Multiple components of Hedgehog and Wnt pathways are localized in the primary cilium. In the human cells possessing the primary cilium (majority of the human cells) Hedgehog and Wnt pathways are located exclusively in primary cilium. The aim of this paper is review of the current knowledge of the biological functions of the primary cilia.
- Keywords
- nádorové buňky, EGFR, PDGFR, Hedgehog, Wnt,
- MeSH
- Cell Cycle physiology MeSH
- Centrioles physiology MeSH
- Cilia physiology metabolism MeSH
- ErbB Receptors physiology MeSH
- Extracellular Space physiology MeSH
- Financing, Organized MeSH
- Cell Physiological Phenomena MeSH
- Humans MeSH
- Cell Transformation, Neoplastic MeSH
- Hedgehog Proteins physiology MeSH
- Wnt Proteins physiology MeSH
- Receptor, Platelet-Derived Growth Factor alpha physiology MeSH
- Signal Transduction physiology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Review MeSH
Osteoporotic fractures are the result of low density and especially inferior bone quality (microarchitecture) caused by both internal (genes, hormones) and external (life style) influences. Bone mechanosensors are extremely important for the overall integrity of the skeleton, because in response to mechanical load they activate its modeling, resulting in an increase in bone density and strength. The largest physiological loads are caused by muscle contractions. Bone mass in adult men has a closer relationship to muscle mass than is case in women. The sexual differences in the relationship between bone and muscle mass are also apparent in children. Based on the mechanostatic theory, the muscle-bone unit has been defined as a functional system whose components are under the common control of the hormones of the somatotropin-IGF-I axis, sexual steroids, certain adipose tissue hormones and vitamin D. The osteogenic effects of somatotropin-IGF-I system are based on the stimulation of bone formation, as well as increase in muscle mass. Moreover, somatotropin decreases the bone mechanostat threshold and reinforces the effect of physical stress on bone formation. The system, via the muscle-bone unit, plays a significant role in the development of the childhood skeleton as well as in its stability during adulthood. The muscle and bone are also the targets of androgens, which increase bone formation and the growth of muscle mass in men and women, independently of IGF-I. The role of further above-mentioned hormones in regulation of this unified functional complex is also discussed.
- MeSH
- Hormones physiology MeSH
- Muscle, Skeletal growth & development physiology MeSH
- Bone and Bones physiology MeSH
- Bone Density physiology MeSH
- Humans MeSH
- Osteoporosis physiopathology MeSH
- Bone Development physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Vlivem biomechanických silových účinků působících na kostní struktury vznikají ve tkáních stavy napjatosti a stavy přetvoření. Anabolické účinky zatěžované kostní tkáně jsou ovlivněny frekvencemi zatížení. Mechanický přenos cyklických silových a deformačních účinků zahrnuje také komplex interakcí mezi smykovými silami vyvozenými tokem extracelulární tekutiny na povrchu příslušné buňky. Cyklické zatěžování kostí stimuluje formace nové kostní tkáně prostřednictvím řady senzorů. Cyklické změny napjatostně deformačních stavů a pulzní toky kapalin v intercelulární síti kanálků a lakun osteocytů mohou být indukovány externím elektronicky regulovaným budičem – elektronickým distrakčním fixátorem (EDF). Dynamické účinky EDF stimulují distrakční osteogenezi (desmogenezi). Prodlužování dlouhých kostí prostřednictvím EDF je regulováno postupným protahováním svalku mezi kostními fragmenty a oscilacemi. Definované velikosti oscilací, iniciované softwarově naprogramovanými silami/ posuny, účinně regulují rychlost remodelace, nárůst únosnosti tkáně a vývoj elastických a viskoelastických vlastností nové kostní tkáně. Aktivita zatěžování může být také softwarově přerušena a programovaně modulována. EDF reguluje délku a doby distrakce, frekvence oscilací a velikosti amplitud (výkmitů). EDF je efektivním klinickým nástrojem pro softwarem regulované stimulace osteogeneze. Presentovaný distrakční fixátor (EDF) je tč. prvním elektronicky řízeným distrakčním fixátorem (prolongátorem) na světě. Jeho předností je schopnost stimulovat remodelaci a regulovat osifikační fázi během distrakcí, prolongovat asymetricky nebo symetricky zkrácené dlouhé kosti dětí/dospělých a přispět k odstranění některých deformit dlouhých kostí u dětí nebo u dospělých
Biomechanical loading affects bone structures. The anabolic effects of cyclic biomechanical loading on bone tissue are influenced by the frequency of loading. Mechanotransduction appears to involve a complex interaction between extracellular fluid shear forces and cellular mechanics. Bone cells are activated by both the cyclic fluid shear stresses and transported ions/molecules in fluid flow. The cyclic loading stimulates new bone formation through (for example) integrin linkages and ion channels. Cyclic stress/strain changes in bone and the cyclic fluid flow in intercellular networks can be induced by the dynamic electronic fixative (EDF). The dynamic effects of EDF stimulate the distraction osteogenesis (desmogenesis). Increasing the rate or frequency by which dynamic loading is applied greatly improves bone tissue mechanosensitivity, possibly due to loading-induced extracellular fluid forces around bone cells, that serve as mechanosensors. The elongation of long bones by EDF is accompanied by the gradual stretching and/or oscillations of the callus between bone fragments. Defined microoscilations of callus between bone fragments initiated by predetermined external force effects very efficiently regulate the healing velocity, the corticalisation – the rise of load bearing tissue structures and the development of elastic and viscoelastic properties of new bone tissue. The active load cycles can be interrupted by the defined tranquillity also. EDF regulates both strain frequencies and amplitude modulations also. EDF presents the effective clinical tool for software regulated osteogenic stimulations within the callus. The presented distraction fixator was originally the first electronically controlled distraction fixation apparatus in the world. Its advantage is the ability to stimulate and regulate the corticalisation of the callus during distraction, to asymmetrically or symmetrically elongate shortened long bones of children/adults and to contribute to the elimination of some deformities of long bones in children or in adul
- Keywords
- prolongátor, stimulace kortikalizace, novotvorba kostní tkáně, distrakce dlouhých kostí, elektronicky regulované oscilace,
- MeSH
- Biomechanical Phenomena * MeSH
- Time Factors MeSH
- Equipment Design MeSH
- Child MeSH
- Adult MeSH
- Electrical Equipment and Supplies * MeSH
- Extracellular Fluid physiology MeSH
- Physical Stimulation methods MeSH
- Ion Transport physiology MeSH
- Bone and Bones physiology metabolism MeSH
- Bony Callus physiology MeSH
- Humans MeSH
- Osteocytes physiology MeSH
- Osteogenesis, Distraction * methods instrumentation utilization MeSH
- Bone Lengthening * methods MeSH
- Bone Remodeling physiology MeSH
- Software MeSH
- Check Tag
- Child MeSH
- Adult MeSH
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
