Focal adhesions are cellular structures through which both mechanical forces and regulatory signals are transmitted. Two focal adhesion-associated proteins, Crk-associated substrate (CAS) and vinculin, were both independently shown to be crucial for the ability of cells to transmit mechanical forces and to regulate cytoskeletal tension. Here, we identify a novel, direct binding interaction between CAS and vinculin. This interaction is mediated by the CAS SRC homology 3 domain and a proline-rich sequence in the hinge region of vinculin. We show that CAS localization in focal adhesions is partially dependent on vinculin, and that CAS-vinculin coupling is required for stretch-induced activation of CAS at the Y410 phosphorylation site. Moreover, CAS-vinculin binding significantly affects the dynamics of CAS and vinculin within focal adhesions as well as the size of focal adhesions. Finally, disruption of CAS binding to vinculin reduces cell stiffness and traction force generation. Taken together, these findings strongly implicate a crucial role of CAS-vinculin interaction in mechanosensing and focal adhesion dynamics.

• MeSH
• Amino Acid Motifs MeSH
• Biomechanical Phenomena MeSH
• Cell Adhesion MeSH
• Cell Line MeSH
• Fibroblasts cytology   metabolism   MeSH
• Focal Adhesions metabolism   ultrastructure   MeSH
• Focal Adhesion Protein-Tyrosine Kinases metabolism   MeSH
• Phosphorylation MeSH
• Protein Interaction Maps MeSH
• Mice MeSH
• Peptides chemistry   metabolism   MeSH
• src Homology Domains MeSH
• Crk-Associated Substrate Protein analysis   metabolism   MeSH
• Protein Binding MeSH
• Vinculin analysis   metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.

• MeSH
• Fibroblasts pathology   MeSH
• Humans MeSH
• Myocardium pathology   MeSH
• Ventricular Remodeling MeSH
• Heart Ventricles pathology   MeSH
• Heart Failure * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

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

Hippo effectors YAP/TAZ act as on-off mechanosensing switches by sensing modifications in extracellular matrix (ECM) composition and mechanics. The regulation of their activity has been described by a hierarchical model in which elements of Hippo pathway are under the control of focal adhesions (FAs). Here we unveil the molecular mechanism by which cell spreading and RhoA GTPase activity control FA formation through YAP to stabilize the anchorage of the actin cytoskeleton to the cell membrane. This mechanism requires YAP co-transcriptional function and involves the activation of genes encoding for integrins and FA docking proteins. Tuning YAP transcriptional activity leads to the modification of cell mechanics, force development and adhesion strength, and determines cell shape, migration and differentiation. These results provide new insights into the mechanism of YAP mechanosensing activity and qualify this Hippo effector as the key determinant of cell mechanics in response to ECM cues.

• MeSH
• Cell Differentiation genetics   physiology   MeSH
• Cell Membrane metabolism   MeSH
• Cell Line MeSH
• Mechanotransduction, Cellular genetics   physiology   MeSH
• Extracellular Matrix metabolism   MeSH
• Focal Adhesions genetics   metabolism   physiology   MeSH
• HEK293 Cells MeSH
• Nuclear Proteins genetics   metabolism   MeSH
• Humans MeSH
• Actin Cytoskeleton metabolism   MeSH
• Cell Line, Tumor MeSH
• Cell Movement genetics   physiology   MeSH
• rhoA GTP-Binding Protein genetics   metabolism   MeSH
• Gene Expression Profiling MeSH
• Transcription Factors genetics   metabolism   MeSH
• Cell Shape MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't 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

Mammary gland is composed of branched epithelial structure embedded within a complex stroma formed by several stromal cell types, including fibroblasts, and extracellular matrix (ECM). Development of mammary gland is tightly regulated by bidirectional epithelial-stromal interactions that include paracrine signaling, ECM remodeling and mechanosensing. Importantly, these interactions play crucial role in mammary gland homeostasis and when deregulated they contribute to tumorigenesis. Therefore, understanding the mechanisms underlying epithelial-stromal interactions is critical for elucidating regulation of normal mammary gland development and homeostasis and revealing novel strategies for breast cancer therapy. To this end, several three-dimensional (3D) cell culture models have been developed to study these interactions in vitro. In this chapter, a novel 3D organoid-fibrosphere coculture model of mammary gland is described with the capacity for studying not only the qualitative and quantitative aspects of interactions between mammary fibroblasts and epithelial organoids but also their radius and directionality.

• MeSH
• Cell Differentiation MeSH
• Spheroids, Cellular cytology   MeSH
• Stromal Cells cytology   MeSH
• Epithelial Cells cytology   MeSH
• Fibroblasts cytology   MeSH
• Coculture Techniques methods   MeSH
• Cells, Cultured MeSH
• Mammary Glands, Animal cytology   MeSH
• Mice MeSH
• Organoids cytology   MeSH
• Paracrine Communication MeSH
• Cell Proliferation MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Interactions between living cells and nanoparticles are extensively studied to enhance the delivery of therapeutics. Nanoparticles size, shape, stiffness, and surface charge are regarded as the main features able to control the fate of cell-nanoparticle interactions. However, the clinical translation of nanotherapies has so far been limited, and there is a need to better understand the biology of cell-nanoparticle interactions. This study investigates the role of cellular mechanosensitive components in cell-nanoparticle interactions. It is demonstrated that the genetic and pharmacologic inhibition of yes-associated protein (YAP), a key component of cancer cell mechanosensing apparatus and Hippo pathway effector, improves nanoparticle internalization in triple-negative breast cancer cells regardless of nanoparticle properties or substrate characteristics. This process occurs through YAP-dependent regulation of endocytic pathways, cell mechanics, and membrane organization. Hence, the study proposes targeting YAP may sensitize triple-negative breast cancer cells to chemotherapy and increase the selectivity of nanotherapy.

• MeSH
• Humans MeSH
• Nanoparticles * MeSH
• YAP-Signaling Proteins MeSH
• Signal Transduction physiology   MeSH
• Triple Negative Breast Neoplasms * drug therapy   metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Within the mandible, the odontogenic and osteogenic mesenchymes develop in a close proximity and form at about the same time. They both originate from the cranial neural crest. These two condensing ecto-mesenchymes are soon separated from each other by a very loose interstitial mesenchyme, whose cells do not express markers suggesting a neural crest origin. The two condensations give rise to mineralized tissues while the loose interstitial mesenchyme, remains as a soft tissue. This is crucial for proper anchorage of mammalian teeth. The situation in all three regions of the mesenchyme was compared with regard to cell heterogeneity. As the development progresses, the early phenotypic differences and the complexity in cell heterogeneity increases. The differences reported here and their evolution during development progressively specifies each of the three compartments. The aim of this review was to discuss the mechanisms underlying condensation in both the odontogenic and osteogenic compartments as well as the progressive differentiation of all three mesenchymes during development. Very early, they show physical and structural differences including cell density, shape and organization as well as the secretion of three distinct matrices, two of which will mineralize. Based on these data, this review highlights the consecutive differences in cell-cell and cell-matrix interactions, which support the cohesion as well as mechanosensing and mechanotransduction. These are involved in the conversion of mechanical energy into biochemical signals, cytoskeletal rearrangements cell differentiation, or collective cell behavior.

• Publication type
• Journal Article MeSH
• Review MeSH

Living cells are constantly exposed to mechanical stimuli arising from the surrounding extracellular matrix (ECM) or from neighboring cells. The intracellular molecular processes through which such physical cues are transformed into a biological response are collectively dubbed as mechanotransduction and are of fundamental importance to help the cell timely adapt to the continuous dynamic modifications of the microenvironment. Local changes in ECM composition and mechanics are driven by a feed forward interplay between the cell and the matrix itself, with the first depositing ECM proteins that in turn will impact on the surrounding cells. As such, these changes occur regularly during tissue development and are a hallmark of the pathologies of aging. Only lately, though, the importance of mechanical cues in controlling cell function (e.g., proliferation, differentiation, migration) has been acknowledged. Here we provide a critical review of the recent insights into the molecular basis of cellular mechanotransduction, by analyzing how mechanical stimuli get transformed into a given biological response through the activation of a peculiar genetic program. Specifically, by recapitulating the processes involved in the interpretation of ECM remodeling by Focal Adhesions at cell-matrix interphase, we revise the role of cytoskeleton tension as the second messenger of the mechanotransduction process and the action of mechano-responsive shuttling proteins converging on stage and cell-specific transcription factors. Finally, we give few paradigmatic examples highlighting the emerging role of malfunctions in cell mechanosensing apparatus in the onset and progression of pathologies.

• Publication type
• Journal Article MeSH
• Review MeSH

Alexander disease (AxD) is a rare and severe neurodegenerative disorder caused by mutations in glial fibrillary acidic protein (GFAP). While the exact disease mechanism remains unknown, previous studies suggest that mutant GFAP influences many cellular processes, including cytoskeleton stability, mechanosensing, metabolism, and proteasome function. While most studies have primarily focused on GFAP-expressing astrocytes, GFAP is also expressed by radial glia and neural progenitor cells, prompting questions about the impact of GFAP mutations on central nervous system (CNS) development. In this study, we observed impaired differentiation of astrocytes and neurons in co-cultures of astrocytes and neurons, as well as in neural organoids, both generated from AxD patient-derived induced pluripotent stem (iPS) cells with a GFAPR239C mutation. Leveraging single-cell RNA sequencing (scRNA-seq), we identified distinct cell populations and transcriptomic differences between the mutant GFAP cultures and a corrected isogenic control. These findings were supported by results obtained with immunocytochemistry and proteomics. In co-cultures, the GFAPR239C mutation resulted in an increased abundance of immature cells, while in unguided neural organoids and cortical organoids, we observed altered lineage commitment and reduced abundance of astrocytes. Gene expression analysis revealed increased stress susceptibility, cytoskeletal abnormalities, and altered extracellular matrix and cell-cell communication patterns in the AxD cultures, which also exhibited higher cell death after stress. Overall, our results point to altered cell differentiation in AxD patient-derived iPS-cell models, opening new avenues for AxD research.

• MeSH
• Alexander Disease * genetics   pathology   metabolism   MeSH
• Astrocytes * metabolism   pathology   MeSH
• Cell Differentiation * physiology   MeSH
• Glial Fibrillary Acidic Protein * metabolism   genetics   MeSH
• Induced Pluripotent Stem Cells * metabolism   MeSH
• Coculture Techniques MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Mutation MeSH
• Neural Stem Cells metabolism   MeSH
• Neurons metabolism   pathology   MeSH
• Organoids metabolism   pathology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH