PIEZO1-mediated mechanosensing governs NK cell killing efficiency in 3D (original) (raw)
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Mechanosensation and Mechanotransduction in Natural Killer Cells
Frontiers in Immunology
Natural killer (NK) cells are a main subset of innate lymphocytes that contribute to host immune protection against viruses and tumors by mediating target cell killing and secreting a wide array of cytokines. Their functions are finely regulated by a balance between activating and inhibitory receptors and involve also adhesive interactions. Mechanotransduction is the process in which physical forces sensed by mechanosensors are translated into chemical signaling. Herein, we report findings on the involvement of this mechanism that is mainly mediated by actin cytoskeleton, in the regulation of NK cell adhesion, migration, tissue infiltration and functions. Actin represents the structural basis for NK cell immunological synapse (NKIS) and polarization of secretory apparatus. NK-target cell interaction involves the formation of both uropods and membrane nanotubes that allow target cell interaction over long distances. Actin retrograde flow (ARF) regulates NK cell signaling and controls...
Nanobody-antigen catch-bond reveals NK cell mechanosensitivity
ABSTRACTAntibodies are key tools in biomedical research and medicine. Their binding properties are classically measured in solution and characterized by an affinity. However, in physiological conditions, antibodies can bridge an immune effector cell and an antigen presenting cell, implying that mechanical forces apply to the bonds. For example, in antibody-dependent cell cytotoxicity, a major mode of action of therapeutic monoclonal antibodies, the Fab domains bind the antigens on the target cell, while the Fc domain binds to the activating receptor CD16 (also known as FcgRIII) of an immune effector cell, in a quasi bi-dimensional environment (2D). Therefore, there is a strong need to investigating antigen/antibody binding under force (2D), to better understand and predict antibody activity in vivo. We used two anti-CD16 nanobodies targeting two different epitopes and laminar flow chamber assay to measure the association and dissociation of single bonds formed between microsphere-bo...
Nanobody-CD16 catch bond reveals NK cell mechanosensitivity
Biophysical Journal
Antibodies are key tools in biomedical research and medicine. Their binding properties are classically measured in solution and characterized by an affinity. However, in physiological conditions, antibodies can bridge an immune effector cell and an antigen presenting cell, implying that mechanical forces may apply to the bonds. For example, in antibody-dependent cell cytotoxicity, a major mode of action of therapeutic monoclonal antibodies, the Fab domains bind the antigens on the target cell, while the Fc domain binds to the activating receptor CD16 (also known as FcgRIII) of an immune effector cell, in a quasi bi-dimensional environment (2D). Therefore, there is a strong need to investigating antigen/antibody binding under force (2D), to better understand and predict antibody activity in vivo. We used two anti-CD16 nanobodies targeting two different epitopes and laminar flow chamber assay to measure the association and dissociation of single bonds formed between microsphere-bound CD16 antigens and surface-bound anti-CD16 nanobodies (or single domain antibodies), simulating 2D encounters. The two nanobodies exhibit similar 2D association kinetics, characterized by a strong dependence on the molecular encounter duration. However, their 2D dissociation kinetics strongly differ as a function of applied force: one exhibits a slip bond behaviour where off-rate increases with force; the other exhibits a catch bond behaviour where off-rate decreases with force. This is the first time, to our knowledge, that catch bond behaviour was reported for antigen-antibody bond. Quantification of NK cells spreading on surfaces coated with the nanobodies provides a comparison between 2D and 3D adhesion in a cellular context, supporting the hypothesis of NK cell mechanosensitivity. Our results may also have strong implications for the design of efficient bispecific antibodies for therapeutic applications.
Cytotoxic lymphocytes use mechanosurveillance to target biophysical vulnerabilities in cancer
ABSTRACTImmune cells identify cancer cells by recognizing characteristic biochemical features indicative of oncogenic transformation. Cancer cells have characteristic mechanical features, as well, but whether these biophysical properties also contribute to destruction by the immune system is not known. In the present study, we found that enhanced expression of myocardin related transcription factors (MRTFs), which promote migration and metastatic invasion, paradoxically compromised lung colonization by melanoma and breast carcinoma cells in an immune-mediated manner. Cancer cells with increased MRTF signaling were also more sensitive to immune checkpoint blockade therapy in mice and humans. The basis for this vulnerability was not biochemical, but biophysical. MRTF expression strengthened the actin cytoskeleton, increasing the rigidity of cancer cells and thereby making them more vulnerable to cytotoxic T lymphocytes and natural killer cells. These results reveal a mechanical dimens...
Mechanosensing in T lymphocyte activation
Mechanical forces play an increasingly recognized role in modulating cell function. This report demonstrates mechanosensing by T cells, using polyacrylamide gels presenting ligands to CD3 and CD28. Naive CD4 T cells exhibited stronger activation, as measured by attachment and secretion of IL-2, with increasing substrate elastic modulus over the range of 10-200 kPa. By presenting these ligands on different surfaces, this report further demonstrates that mechanosensing is more strongly associated with CD3 rather than CD28 signaling. Finally, phospho-specific staining for Zap70 and Src family kinase proteins suggests that sensing of substrate rigidity occurs at least in part by processes downstream of T-cell receptor activation. The ability of T cells to quantitatively respond to substrate rigidly provides an intriguing new model for mechanobiology.
Mechanosensation of cyclical force by PIEZO1 is essential for innate immunity
Nature, 2019
Although cells of the immune system experience force and pressure throughout their lifecycle, almost nothing is known about how these mechanical processes regulate the immune response 1. Both tissue-resident and tissue-infiltrating immune cells in highly mechanical organs, such as the lung, are constantly exposed to tonic and dynamically changing mechanical cues 2. Here using reverse genetics, we show that myeloid cells respond to force and alterations in cyclical hydrostatic pressure via the mechanosensory ion channel PIEZO1 3. Unbiased RNA sequencing from macrophages subjected to cyclical hydrostatic pressure reveals a striking state of proinflammatory reprogramming. We report a novel mechanosensory-immune signaling circuit which PIEZO1 initiates in response to cyclical hydrostatic pressure, driving c-JUN activation and transcriptional upregulation of Endothelin-1 (EDN1). EDN1 in turn stabilizes HIF1α, which facilitates transcription of a potent and prolonged program of proinflammatory mediators. Using mice conditionally deficient of PIEZO1 in myeloid cells, and cellular depletion assays, we show 10
Cancers, 2020
Mechanotransduction, the translation of mechanical stimuli into biological signals, is a crucial mechanism involved in the function of fundamentally all cell types. In many solid tumors, the malignant transformation is often associated with drastic changes in cell mechanical features. Extracellular matrix stiffness, invasive growth, and cell mobility are just a few hallmarks present in cancer cells that, by inducing mechanical stimuli, create positive feedbacks promoting cancer development. Among the molecular players involved in these pathophysiological processes, the mechanosensitive Ca2+-permeable Piezo channels have emerged as major transducers of mechanical stress into Ca2+ dependent signals. Piezo channels are overexpressed in several cancers, such as in breast, gastric, and bladder, whereas their downregulation has been described in other cancers. Still, the roles of mechanosensitive Piezos in cancer are somewhat puzzling. In this review, we summarize the current knowledge on...
Mechanically activated ion channel Piezo1 modulates macrophage polarization and stiffness sensing
Nature Communications, 2021
Macrophages perform diverse functions within tissues during immune responses to pathogens and injury, but molecular mechanisms by which physical properties of the tissue regulate macrophage behavior are less well understood. Here, we examine the role of the mechanically activated cation channel Piezo1 in macrophage polarization and sensing of microenvironmental stiffness. We show that macrophages lacking Piezo1 exhibit reduced inflammation and enhanced wound healing responses. Additionally, macrophages expressing the transgenic Ca 2+ reporter, Salsa6f, reveal that Ca 2+ influx is dependent on Piezo1, modulated by soluble signals, and enhanced on stiff substrates. Furthermore, stiffnessdependent changes in macrophage function, both in vitro and in response to subcutaneous implantation of biomaterials in vivo, require Piezo1. Finally, we show that positive feedback between Piezo1 and actin drives macrophage activation. Together, our studies reveal that Piezo1 is a mechanosensor of stiffness in macrophages, and that its activity modulates polarization responses.
Cytotoxic T Cells Use Mechanical Force to Potentiate Target Cell Killing
Cell, 2016
Highlights d T cell cytotoxicity correlates with the exertion of mechanical force d Force exertion is associated with enhanced perforin pore formation on the target cell d Cell tension promotes perforin pore formation d Cytotoxic T cells spatiotemporally coordinate force exertion and perforin release