Team:ShanghaiTech China/Design
INSULEN
An Intelligent N-palmitoyl serinol System Utilizing Light-controlled ENterobacterium for diabetic therapy, aiming to develop an intelligent system to regulate Type 2 diabetes (T2D) patients’ blood sugar level by controlling the secretion of a type of molecule-N-palmitoyl serinol in the intestine through a light control system. The implementation of this system consists of four steps: engineered bacteria design, bacteria drug delivery, blood sugar level detection, and Near-Infrared Light(NIR) intelligent regulation.
1.Engineered bacteria design
N-palmitoyl serinol is considered to have an impact on regulating the blood sugar level by interacting with G-Protein Coupled Receptor (GPCR) in the intestine [1]. It will help reduce the glucose level and contribute to the treatment of diabetes. Therefore, the engineered bacteria are designed to carry the N-acyl synthase (NAS) gene so that they can express the relative enzyme and synthesize N-acyl amide under the suitable control system.
The expression of NAS gene is regulated by the light-inducible system:pDawn, of which the mechanism is shown in the figure. It is a robust gene expression system acting as a light-activated manner with blue light activating the expression of target genes, of which the effect can be greatly enhanced with either the increase of light intensity or the extension of the duration of illumination. The system features the histidine kinase YF1 constitutively expressed from the LacIq promoter. In the absence of the blue light, YF1 phosphorylates its cognate response regulator FixJ, which then drives significant gene expression from the FixK2 promoter and upon light absorption, the expression can be therefore suppressed. Target genes can be introduced via a multiple-cloning site (MCS), and after that, insertion of the λ phage repressor cI driven by FixK2 represses λ promoter pR in pDawn [2] , inverting signal polarity and renders gene expression light activated.
Considering the problem that it’s hard for the blue light to pass through the human body and reach the intestine, a kind of nanoparticles which can convert Near-Infrared Light (NIR) to blue light in vivo are introduced into our system [3]. NIR has been widely accepted as a tool of medical examination due to its better penetration and high security. Therefore, by giving NIR to the patients, the upconversion nanoparticles can convert NIR to blue light in the intestine, which induces the expression of NAS gene through pDawn system.
2.Bacteria drug delivery
According to the design of our engineered bacteria, they are aimed to settle down in the human’s gut. Therefore, it is necessary to come up with a way to deliver the engineered bacteria to the intestine. The safety of both bacteria and human also need to be carefully considered. Therefore, agarose vesicles turn out to be good bacteria carriers. they can protect engineered bacteria from the adverse conditions in the gut while keeping the bacteria grow in the vesicles so that the intestinal bacteria balance won’t be affected by the foreign bacteria. In this case, enteric-coated capsule containing engineered bacteria in agarose vesicles is constructed. The capsule is released in the gut and will protect the bacteria from being killed by stomach acids. The vesicles may help bacteria adhere to the intestinal wall so that the bacteria drug can be successfully delivered to the human’s gut.
3.Blood sugar level detection
With the development of modern medical technology, there has been blood sugar monitor on the market which can detect patients’ real-time blood sugar level without blood taking, and transfer data to the patients’ devices so that they can acquire their real-time blood sugar data. To capture the real-time data from the monitor, an INSULEN APP is designed to receive data generated by the blood sugar monitor. Through this app, patients can acquire their blood sugar status easily. Also, further regulation of the device will be carried out based the acquired data.
4.Near-infrared light intelligent regulation
To realize intelligent regulation, a wearable gene expression control device, named “INSULEN Waist Pack” is designed. It is equipped with tape lights which emit NIR to induce the engineered bacteria in the intestine. The data received from the blood sugar monitor is then treated to be a visible line chart, determine whether the patients need to be treated with NIR. The signal will be sent through Bluetooth to the INSULEN Waist Pack to guide its work. In conclusion, the whole system can be regulated by real-time blood sugar data so that patients can be treated with NIR to relieve diabetes automatically. Therefore, it is obvious that our system of treating diabetes is much more convenient, flexible and patient-centered.
References
[1] Cohen, L. J. et al. Commensal bacteria make GPCR ligands that mimic human signalling molecules. Nature 549, 48-+, doi:10.1038/nature23874 (2017).
[2] Ohlendorf, R., Vidavski, R. R., Eldar, A., Moffat, K. & Moglich, A. From dusk till dawn: one-plasmid systems for light-regulated gene expression. J Mol Biol 416, 534-542, doi:10.1016/j.jmb.2012.01.001 (2012).
[3] Ma, Y. et al. Mammalian Near-Infrared Image Vision through Injectable and Self-Powered Retinal Nanoantennae. Cell 177, 243-255 e215, doi:10.1016/j.cell.2019.01.038 (2019).