Nanoscale Arrangement of Apoptotic Ligands Reveals a Demand for a Minimal Lateral Distance for Efficient Death Receptor Activation

Department of New Materials and Biosystems, Max-Planck-Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany.
Nano Letters (Impact Factor: 13.59). 09/2009; 9(12):4240-5. DOI: 10.1021/nl902429b
Source: PubMed


Cellular apoptosis, the prototype of programmed cell death, can be induced by activation of so-called death receptors. Interestingly, soluble and membrane-bound members of death receptor ligands can differentially activate their receptors. Using the death receptor ligand tumor necrosis factor (TNF) presented on a surface in a nanoscaled pattern with spacings between 58 and 290 nm, we investigated its requirements for spatial arrangement and motility to efficiently activate TNF receptor (TNFR)1 and TNFR2 as well as its chimeras TNFR1-Fas and TNFR2-Fas. We show that the mere mechanical fixation of TNF is insufficient to efficiently activate TNFR2 that is responsive to only the membrane bound form of TNF but not its soluble form. Rather, an additional stabilization of TNFR2(-Fas) by cluster formation seems to be mandatory for efficient activation. In contrast, TNFR1(-Fas) is strongly activated by TNF spaced within up to 200 nm distances, whereas larger spacings of 290 nm fails completely. Furthermore, unlike for TNFR2(-Fas) no dose-response relationship to increasing distances of nanostructured ligands could be observed for TNFR1-(Fas), suggesting that compartmentalization of the cell membrane in confinement zones of approximately 200 nm regulates TNFR1 activation.

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    • "These interactions regulate mammalian cellular functions including apoptosis, signal transduction, enzymatic reactions and cell-cell interactions8. The receptor molecules must be precisely assembled to enhance the molecular interactions required for initiating signal transduction9. Likewise, the polymer system bears improvements for precisely regulating the cell-surface receptor function in synthetic biology. "
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    ABSTRACT: A human cell surface displays many complex-structured receptors for receiving extracellular signals to regulate cellular functions. The use of precisely regulated signal-controls of the receptors could have possibilities beyond the current synthetic biology research that begins with the transfection of exogenous molecules to rewire intracellular circuits. However, by using a current ligand-receptor technique, the configuration of the artificially assembled cell surface molecules has been undefined because the assemblage is an unsystematic molecular clustering. Thus, the system bears improvements for precisely regulating receptor functions. We report here a new tool that refines stereochemically-controlled positioning of an assembled surface receptor. The tool performs rationally as an ON/OFF switch and is finely tunable so that a 3 to 6 nm size difference of the device precisely distinguishes the efficiency of apoptosis induced via cell-surface receptor binding. We discuss the potential use of the device in next-generation synthetic biology and in cell surface studies.
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    • "While the mechanism behind the effect of topography on cell function is not clearly understood, it is believed that it modulates cell attachment through contact guidance, and produces anisotropic stresses in the cell's cytoskeleton (Bettinger et al., 2009). Control over the nanotopography of scaffolds has been shown to influence cell shape (Kim et al., 2010a), adhesion, migration, proliferation (Ranzinger et al., 2009) and differentiation (Yang et al., 2011) and hence provides an additional degree of control in the design of biomaterials used to engineer functioning tissues. "
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    ABSTRACT: Micro- and nanotechnologies have emerged as potentially effective fabrication tools for addressing the challenges faced in tissue engineering and drug delivery. The ability to control and manipulate polymeric biomaterials at the micron and nanometre scale with these fabrication techniques has allowed for the creation of controlled cellular environments, engineering of functional tissues and development of better drug delivery systems. In tissue engineering, micro- and nanotechnologies have enabled the recapitulation of the micro- and nanoscale detail of the cell's environment through controlling the surface chemistry and topography of materials, generating 3D cellular scaffolds and regulating cell-cell interactions. Furthermore, these technologies have led to advances in high-throughput screening (HTS), enabling rapid and efficient discovery of a library of materials and screening of drugs that induce cell-specific responses. In drug delivery, controlling the size and geometry of drug carriers with micro- and nanotechnologies have allowed for the modulation of parametres such as bioavailability, pharmacodynamics and cell-specific targeting. In this review, we introduce recent developments in micro- and nanoscale engineering of polymeric biomaterials, with an emphasis on lithographic techniques, and present an overview of their applications in tissue engineering, HTS and drug delivery. Copyright © 2012 John Wiley & Sons, Ltd.
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    • "Cross-linking experiments with TNFR1-Fas and TNFR2-Fas also suggest the formation of homodimers in the absence of a ligand [27]. These homo-dimers/trimers of receptors then build up to form cluster-aggregates on the cell surface upon ligand binding [28,29]. The CRD1 domain has also been shown to be important for stabilizing the CRD2 domain for efficient ligand binding [26]. "
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