A Synthetic Optogenetic Transcription Device Enhances Blood-Glucose Homeostasis in Mice

Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland.
Science (Impact Factor: 33.61). 06/2011; 332(6037):1565-8. DOI: 10.1126/science.1203535
Source: PubMed

ABSTRACT Synthetic biology has advanced the design of genetic devices that can be used to reprogram metabolic activities in mammalian cells. By functionally linking the signal transduction of melanopsin to the control circuit of the nuclear factor of activated T cells, we have designed a synthetic signaling cascade enabling light-inducible transgene expression in different cell lines grown in culture or bioreactors or implanted into mice. In animals harboring intraperitoneal hollow-fiber or subcutaneous implants containing light-inducible transgenic cells, the serum levels of the human glycoprotein secreted alkaline phosphatase could be remote-controlled with fiber optics or transdermally regulated through direct illumination. Light-controlled expression of the glucagon-like peptide 1 was able to attenuate glycemic excursions in type II diabetic mice. Synthetic light-pulse-transcription converters may have applications in therapeutics and protein expression technology.

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    • "The capsules may, for example, not be impervious over time, possibly exposing the engineered cells to the patients' immune system. Furthermore , the current version of the circuits are operated in standard tissue culture cells originally derived from cultures of human embryonic kidney cells transformed with sheared adenovirus 5 DNA (HEK-293 cells) (Kemmer et al. 2010; Ye et al. 2011). These cells have several chromosomal abnormalities and share other features with human cancer cells. "
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    ABSTRACT: Recent progress in synthetic biology (SynBio) has enabled the development of novel therapeutic opportunities for the treatment of human disease. In the near future, first-in-human trials (FIH) will be indicated. FIH trials mark a key milestone in the translation of medical SynBio applications into clinical practice. Fostered by uncertainty of possible adverse events for trial participants, a variety of ethical concerns emerge with regards to SynBio FIH trials, including 'risk' minimization. These concerns are associated with any FIH trial, however, due to the novelty of the approach, they become more pronounced for medical applications of emerging technologies (emTech) like SynBio. To minimize potential harm for trial participants, scholars, guidelines, regulations and policy makers alike suggest using 'risk assessment' as evaluation tool for such trials. Conversely, in the context of emTech FIH trials, we believe it to be at least questionable to contextualize uncertainty of potential adverse events as 'risk' and apply traditional risk assessment methods. Hence, this issue needs to be discussed to enable alterations of the evaluation process before the translational phase of SynBio applications begins. In this paper, we will take the opportunity to start the debate and highlight how a misunderstanding of the concept of risk, and the possibilities and limitations of risk assessment, respectively, might impair decision-making by the relevant regulatory authorities and research ethics committees, and discuss possible solutions to tackle the issue.
    Medicine Health Care and Philosophy 08/2015; DOI:10.1007/s11019-015-9660-7 · 0.91 Impact Factor
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    • "During the past decade, mammalian synthetic biology has progressed from simple control switches providing trigger-inducible transgene expression to complex transcription/translation networks enabling oscillating expression dynamics (Tigges et al., 2009), intercellular communication (Bacchus et al., 2012), and fundamental arithmetic operations (Auslä nder et al., 2012). To date, synthetic biology-inspired biomedical applications have been successfully tested in animal models including T cell therapy (Chen et al., 2010), treatment of gouty arthritis (Kemmer et al., 2010), obesity (Rö ssger et al., 2013b), and type 2 diabetes (Ye et al., 2011). Type 1 diabetes mellitus is a chronic metabolic disease that is characterized by excessive blood glucose levels resulting from autoimmune destruction of insulin-producing b cells in the islets of Langerhans of the pancreas (Pozzilli, 2012). "
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    ABSTRACT: All metabolic activities operate within a narrow pH range that is controlled by the CO2-bicarbonate buffering system. We hypothesized that pH could serve as surrogate signal to monitor and respond to the physiological state. By functionally rewiring the human proton-activated cell-surface receptor TDAG8 to chimeric promoters, we created a synthetic signaling cascade that precisely monitors extracellular pH within the physiological range. The synthetic pH sensor could be adjusted by organic acids as well as gaseous CO2 that shifts the CO2-bicarbonate balance toward hydrogen ions. This enabled the design of gas-programmable logic gates, provided remote control of cellular behavior inside microfluidic devices, and allowed for CO2-triggered production of biopharmaceuticals in standard bioreactors. When implanting cells containing the synthetic pH sensor linked to production of insulin into type 1 diabetic mice developing diabetic ketoacidosis, the prosthetic network automatically scored acidic pH and coordinated an insulin expression response that corrected ketoacidosis.
    Molecular Cell 07/2014; DOI:10.1016/j.molcel.2014.06.007 · 14.02 Impact Factor
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    • "It has been previously found that specific patterns of cellular calcium oscillation can initiate signaling of gene expression1234. Recently, progresses on optogenetics56789101112, heat-activated promoters13, and gene/protein modification combined with nanoparticles and radio wave14 have successfully demonstrated controllable expression of some genes. However, all those methods include at least three complicated phases: 1) gene or protein engineering/modification, 2) introduction of those bioengineered exogenous materials into cells, and 3) activation of those materials to express corresponding genes by some chemical or physical stimulation. "
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    ABSTRACT: Controllable gene expression is always a challenge and of great significance to biomedical research and clinical applications. Recently, various approaches based on extra-engineered light-sensitive proteins have been developed to provide optogenetic actuators for gene expression. Complicated biomedical techniques including exogenous genes engineering, transfection, and material delivery are needed. Here we present an all-optical method to regulate gene expression in targeted cells. Intrinsic or exogenous genes can be activated by a Ca(2+)-sensitive transcription factor nuclear factor of activated T cells (NFAT) driven by a short flash of femtosecond-laser irradiation. When applied to mesenchymal stem cells, expression of a differentiation regulator Osterix can be activated by this method to potentially induce differentiation of them. A laser-induced "Ca(2+)-comb" (LiCCo) by multi-time laser exposure is further developed to enhance gene expression efficiency. This noninvasive method hence provides an encouraging advance of gene expression regulation, with promising potential of applying in cell biology and stem-cell science.
    Scientific Reports 06/2014; 4:5346. DOI:10.1038/srep05346 · 5.58 Impact Factor
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