Eosinophil‐derived exosomes can act as functional units and are able to autoregulate eosinophil function.
Eosinophils are able to secrete exosomes that have an undefined role in asthma pathogenesis. ...We hypothesized that exosomes released by eosinophils autoregulate and promote eosinophil function. Eosinophils of patients with asthma (n = 58) and healthy volunteers (n = 16) were purified from peripheral blood, and exosomes were isolated and quantified from eosinophils of the asthmatic and healthy populations. Apoptosis, adhesion, adhesion molecules expression, and migration assays were performed with eosinophils in the presence or absence of exosomes from healthy and asthmatic individuals. Reactive oxygen species (ROS) were evaluated by flow cytometry with an intracellular fluorescent probe and nitric oxide (NO) and a colorimetric kit. In addition, exosomal proteins were analyzed by mass spectrometry. Eosinophil‐derived exosomes induced an increase in NO and ROS production on eosinophils. Moreover, exosomes could act as a chemotactic factor on eosinophils, and they produced an increase in cell adhesion, giving rise to a specific augmentation of adhesion molecules, such as ICAM‐1 and integrin α2. Protein content between exosomes from healthy and asthmatic individuals seems to be similar in both groups. In conclusion, we found that exosomes from the eosinophils of patients with asthma could modify several specific eosinophil functions related to asthma pathogenesis and that they could contribute fundamentally to the development and maintenance of asthma.
Facile fabrication of asymmetrically adhesive hydrogel with robust wet tissue adhesion simultaneously with effective anti‐postoperative adhesion still remains a great challenge. In this work, an ...integrally formed Janus hydrogel is facilely fabricated in one step by controlling the interfacial distribution of free carboxyl groups on the two sides of hydrogels. At a lower stirring speed, the generated bigger sized emulsion droplets mainly occupy the top surface of hydrogel, which effectively hinders the exposition of carboxyl groups on the top surface, driving them to be more distributed on the bottom surface, ultimately resulting in the poor adhesion of top surface but robust adhesion of bottom surface to various wet tissue even underwater. The difference in adhesive strength achieves as high as 20 times between the two surfaces. In vivo rabbit experiment outcomes clearly validate that the bottom surface of hydrogel firmly adheres to the stomach defect, and the other opposite surface can efficiently address the postoperative adhesion problem. Besides, this hydrogel exhibits superior mechanical toughness and conductivity which has been used as a highly adhesive strain sensor to real‐time monitor the beating heart in vivo. This simple yet effective strategy provides a much more feasible approach for creating Janus hydrogels bioadhesives.
An integrally formed asymmetrically adhesive hydrogel is fabricated by controlling the interfacial distribution of free –COOH groups via simply adjusting the stirring speed. The difference in adhesive strength achieves as high as 20 times between the two sides of one hydrogel, which attains one‐sided robust adhesion to the wet tissue, simultaneously preventing the postoperative adhesion for the opposite side.
Total knee arthroplasty (TKA) inevitably perturbs the femoral medullary canal, which increases blood loss or morbidities associated with marrow embolization postoperatively. Computer navigation TKA ...reportedly minimizes medullary disturbance to alleviate perioperative blood loss. We performed a prospective comparative study, enrolling 87 patients with osteoarthritic knees from March 2011 to December 2011 in our hospital. The patients were separated into two groups, according to the surgeon they visited. Fifty-four patients underwent computer navigation TKAs and 33 had conventional TKAs. Levels of cell adhesion molecules (CAMs), including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and platelet endothelial cellular adhesion molecule-1 (PECAM-1) in sera and hemovac drainage were measured by ELISA before and 24 hours after the surgery. We showed that patients receiving computer navigation TKAs had less blood loss and lower CAMs in serum and hemovac drainage after the operation. Less postoperative elevation of serum ICAM-1 (p=0.022) and PECAM-1 (p=0.003) from the preoperative baseline after the surgery was also noted. This study provides molecular evidence for the differential extent in vascular injury between conventional and navigation TKAs and sheds light on the possible benefits of computer navigation TKAs.
ClinicalTrials.gov NCT02206321.
Focal adhesions (FAs) are macromolecular complexes that regulate cell adhesion and mechanotransduction. By performing fluorescence recovery after photobleaching (FRAP) and fluorescence loss after ...photoactivation (FLAP) experiments, we found that the mobility of core FA proteins correlates with their function. Structural proteins such as tensin, talin and vinculin are significantly less mobile in FAs than signaling proteins such as FAK (also known as PTK2) and paxillin. The mobilities of the structural proteins are directly influenced by substrate stiffness, suggesting that they are involved in sensing the rigidity of the extracellular environment. The turnover rates of FAK and paxillin, as well as kindlin2 (also known as FERMT2), are not influenced by substrate stiffness. By using specific Src and FAK inhibitors, we reveal that force-sensing by vinculin occurs independently of FAK and paxillin phosphorylation. However, their phosphorylation is required for downstream Rac1-driven cellular processes, such as protrusion and cell migration. Overall, we show that the FA is composed of different functional modules that separately control mechanosensing and the cellular mechano-response.
Formation of distant metastases is by far the most common cause of cancer-related deaths. The process of metastasis formation is complex, and within this complex process the formation of migratory ...cells, the so called epithelial mesenchymal transition (EMT), which enables cancer cells to break loose from the primary tumor mass and to enter the bloodstream, is of particular importance. To break loose from the primary cancer, cancer cells have to down-regulate the cell-to-cell adhesion molecuIes (CAMs) which keep them attached to neighboring cancer cells. In contrast to this downregulation of CAMS in the primary tumor, cancer cells up-regulate other types of CAMs, that enable them to attach to the endothelium in the organ of the future metastasis. During EMT, the expression of cell-to-cell and cell-to-matrix adhesion molecules and their down- and upregulation is therefore critical for metastasis formation. Tumor cells mimic leukocytes to enable transmigration of the endothelial barrier at the metastatic site. The attachment of leukocytes/cancer cells to the endothelium are mediated by several CAMs different from those at the site of the primary tumor. These CAMs and their ligands are organized in a sequential row, the leukocyte adhesion cascade. In this adhesion process, integrins and their ligands are centrally involved in the molecular interactions governing the transmigration. This review discusses the integrin expression patterns found on primary tumor cells and studies whether their expression correlates with tumor progression, metastatic capacity and prognosis. Simultaneously, further possible, but so far unclearly characterized, alternative adhesion molecules and/or ligands, will be considered and emerging therapeutic possibilities reviewed.
Cell adhesion molecules are ubiquitous in multicellular organisms, specifying precise cell-cell interactions in processes as diverse as tissue development, immune cell trafficking and the wiring of ...the nervous system
. Here we show that a wide array of synthetic cell adhesion molecules can be generated by combining orthogonal extracellular interactions with intracellular domains from native adhesion molecules, such as cadherins and integrins. The resulting molecules yield customized cell-cell interactions with adhesion properties that are similar to native interactions. The identity of the intracellular domain of the synthetic cell adhesion molecules specifies interface morphology and mechanics, whereas diverse homotypic or heterotypic extracellular interaction domains independently specify the connectivity between cells. This toolkit of orthogonal adhesion molecules enables the rationally programmed assembly of multicellular architectures, as well as systematic remodelling of native tissues. The modularity of synthetic cell adhesion molecules provides fundamental insights into how distinct classes of cell-cell interfaces may have evolved. Overall, these tools offer powerful abilities for cell and tissue engineering and for systematically studying multicellular organization.
The integrity of transplanted mesenchymal stem cells (MSCs) for cardiac regeneration is dependent on cell-cell or cell-matrix adhesion, which is inhibited by reactive oxygen species (ROS) generated ...in ischemic surroundings after myocardial infarction. Intracellular ROS play a key role in the regulation of cell adhesion, migration, and proliferation. This study was designed to investigate the role of ROS on MSC adhesion. In H(2)O(2) treated MSCs, adhesion and spreading were inhibited and detachment was increased in a dose-dependent manner, and these effects were significantly rescued by co-treatment with the free radical scavenger, N-acetyl-L-cysteine (NAC, 1 mM). A similar pattern was observed on plates coated with different matrices such as fibronectin and cardiogel. Hydrogen peroxide treatment resulted in a marked decrease in the level of focal adhesion-related molecules, such as phospho-FAK and p-Src in MSCs. We also observed a significant decrease in the integrin-related adhesion molecules, alpha V and beta1, in H(2)O(2) treated MSCs. When injected into infarcted hearts, the adhesion of MSCs co-injected with NAC to the border region was significantly improved. Consequently, we observed that fibrosis and infarct size were reduced in MSC and NAC-injected rat hearts compared to in MSC-only injected hearts. These results indicate that ROS inhibit cellular adhesion of engrafted MSCs and provide evidence that the elimination of ROS might be a novel strategy for improving the survival of engrafted MSCs.
High-grade gliomas (HGG) are a devastating group of cancers, and represent the leading cause of brain tumour-related death in both children and adults. Therapies aimed at mechanisms intrinsic to ...glioma cells have translated to only limited success; effective therapeutic strategies will need also to target elements of the tumour microenvironment that promote glioma progression. Neuronal activity promotes the growth of a range of molecularly and clinically distinct HGG types, including adult and paediatric glioblastoma (GBM), anaplastic oligodendroglioma, and diffuse intrinsic pontine glioma (DIPG). An important mechanism that mediates this neural regulation of brain cancer is activity-dependent cleavage and secretion of the synaptic adhesion molecule neuroligin-3 (NLGN3), which promotes glioma proliferation through the PI3K-mTOR pathway. However, the necessity of NLGN3 for glioma growth, the proteolytic mechanism of NLGN3 secretion, and the further molecular consequences of NLGN3 secretion in glioma cells remain unknown. Here we show that HGG growth depends on microenvironmental NLGN3, identify signalling cascades downstream of NLGN3 binding in glioma, and determine a therapeutically targetable mechanism of secretion. Patient-derived orthotopic xenografts of paediatric GBM, DIPG and adult GBM fail to grow in Nlgn3 knockout mice. NLGN3 stimulates several oncogenic pathways, such as early focal adhesion kinase activation upstream of PI3K-mTOR, and induces transcriptional changes that include upregulation of several synapse-related genes in glioma cells. NLGN3 is cleaved from both neurons and oligodendrocyte precursor cells via the ADAM10 sheddase. ADAM10 inhibitors prevent the release of NLGN3 into the tumour microenvironment and robustly block HGG xenograft growth. This work defines a promising strategy for targeting NLGN3 secretion, which could prove transformative for HGG therapy.
Objective
While endothelial dysfunction has been implicated in the widespread thromboinflammatory complications of COVID‐19, the upstream mediators of endotheliopathy remain, for the most part, ...unknown. This study was undertaken to identify circulating factors contributing to endothelial cell activation and dysfunction in COVID‐19.
Methods
Human endothelial cells were cultured in the presence of serum or plasma from 244 patients hospitalized with COVID‐19 and plasma from 100 patients with non–COVID‐19–related sepsis. Cell adhesion molecules (E‐selectin, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1 ICAM‐1) were quantified using in‐cell enzyme‐linked immunosorbent assay.
Results
Serum and plasma from COVID‐19 patients increased surface expression of cell adhesion molecules. Furthermore, levels of soluble ICAM‐1 and E‐selectin were elevated in patient serum and correlated with disease severity. The presence of circulating antiphospholipid antibodies was a strong marker of the ability of COVID‐19 serum to activate endothelium. Depletion of total IgG from antiphospholipid antibody–positive serum markedly reduced the up‐regulation of cell adhesion molecules. Conversely, supplementation of control serum with patient IgG was sufficient to trigger endothelial activation.
Conclusion
These data are the first to indicate that some COVID‐19 patients have potentially diverse antibodies that drive endotheliopathy, providing important context regarding thromboinflammatory effects of autoantibodies in severe COVID‐19.
Integrin adhesion complexes (IACs) form mechanochemical connections between the extracellular matrix and actin cytoskeleton and mediate phenotypic responses via posttranslational modifications. Here, ...we investigate the modularity and robustness of the IAC network to pharmacological perturbation of the key IAC signaling components focal adhesion kinase (FAK) and Src. FAK inhibition using AZ13256675 blocked FAK(Y397) phosphorylation but did not alter IAC composition, as reported by mass spectrometry. IAC composition was also insensitive to Src inhibition using AZD0530 alone or in combination with FAK inhibition. In contrast, kinase inhibition substantially reduced phosphorylation within IACs, cell migration and proliferation. Furthermore using fluorescence recovery after photobleaching, we found that FAK inhibition increased the exchange rate of a phosphotyrosine (pY) reporter (dSH2) at IACs. These data demonstrate that kinase-dependent signal propagation through IACs is independent of gross changes in IAC composition. Together, these findings demonstrate a general separation between the composition of IACs and their ability to relay pY-dependent signals.
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