Showing 1 - 3 of 3 results
A micro-nano optogenetic system based on probiotics for in situ host metabolism regulation.
Genetically engineered bacteria have aroused attention as micro-nano drug delivery systems in situ. However, conventional designs of engineered bacteria usually function constantly or autonomously, which might be non-specific or imprecise. Therefore, designing and optimizing in situ control strategy are important methodological progress for therapeutic researches of intestinal engineered bacteria. Here, a micro-nano optogenetic system based on probiotic was developed combining microelectronics, nanotechnology, and synthetic biology to achieve in situ controllable drug delivery. Firstly, optogenetic engineered Lactococcus lactis was orally administrated in the intestinal tract. A wearable optical device was designed to control optical signals remotely. Then, L. lactis could be customized to secrete peptides according to optical signals. As an example, optogenetic L. lactis system can be constructed to secrete glucagon-like peptide-1 (GLP-1) under the control of the wearable optical device to regulate metabolism. To improve the half-life of GLP-1 in vivo, Fc-domain fused GLP-1 was optimally used. Using this strategy, blood glucose, weight, and other features were well controlled in rats and mice models. Furthermore, upconversion microcapsules were introduced to increase the excitation wavelength of the optogenetic system for better penetrability. This strategy has biomedical potential to expand the toolbox for intestinal engineered bacteria.
Spatiotemporal regulation of ubiquitin-mediated protein degradation via upconversion optogenetic nanosystem.
Protein degradation technology, which is one of the most direct and effective ways to regulate the life activities of cells, is expected to be applied to the treatment of various diseases. However, current protein degradation technologies such as some small-molecule degraders which are unable to achieve spatiotemporal regulation, making them difficult to transform into clinical applications. In this article, an upconversion optogenetic nanosystem was designed to attain accurate regulation of protein degradation. This system worked via two interconnected parts: 1) the host cell expressed light-sensitive protein that could trigger the ubiquitinproteasome pathway upon blue-light exposure; 2) the light regulated light-sensitive protein by changing light conditions to achieve regulation of protein degradation. Experimental results based on model protein (Green Fluorescent Protein, GFP) validated that this system could fulfill protein degradation both in vitro (both Hela and 293T cells) and in vivo (by upconversion optogenetic nanosystem), and further demonstrated that we could reach spatiotemporal regulation by changing the illumination time (0–25 h) and the illumination frequency (the illuminating frequency of 0–30 s every 1 min). We further took another functional protein (The Nonstructural Protein 9, NSP9) into experiment. Results confirmed that the proliferation of porcine reproductive and respiratory syndrome virus (PRRSV) was inhibited by degrading the NSP9 in this light-induced system, and PRRSV proliferation was affected by different light conditions (illumination time varies from 0–24 h). We expected this system could provide new perspectives into spatiotemporal regulation of protein degradation and help realize the clinical application transformation for treating diseases of protein degradation technology.
Reversible hydrogels with tunable mechanical properties for optically controlling cell migration.
Synthetic hydrogels are widely used as biomimetic in vitro model systems to understand how cells respond to complex microenvironments. The mechanical properties of hydrogels are deterministic for many cellular behaviors, including cell migration, spreading, and differentiation. However, it remains a major challenge to engineer hydrogels that recapture the dynamic mechanical properties of native extracellular matrices. Here, we provide a new hydrogel platform with spatiotemporally tunable mechanical properties to assay and define cellular behaviors under light. The change in the mechanical properties of the hydrogel is effected by a photo-induced switch of the cross-linker fluorescent protein, Dronpa145N, between the tetrameric and monomeric states, which causes minimal changes to the chemical properties of the hydrogel. The mechanical properties can be rapidly and reversibly tuned for multiple cycles using visible light, as confirmed by rheological measurements and atomic force microscopybased nano-indentation. We further demonstrated real-time and reversible modulation of cell migration behaviors on the hydrogels through photo-induced stiffness switching, with minimal invasion to the cultured cells. Hydrogels with a programmable mechanical history and a spatially defined mechanical hierarchy might serve as an ideal model system to better understand complex cellular functions.