20.109(F11): Light based therapeutics
Light Based Therapeutics
In an effort to combine elements of the three different Modules we pursued in 20.109, we wish to explore light based therapeutics as a method to address significant unmet medical or research needs. Light is very non-invasive compared to other common inputs, which may involve flooding a cell with protein or chemical, which does not translate well to in vivo tests within an actual living system. Recently, a lot of work has been done within the field of optigenetics, which combines optical methods and genetic regulation to achieve control within living organisms.
Our goal is to construct useful novel circuits, which would sense light as an input, and modularly release a product or response (eg. apoptosis protein). We're exploring different methods of delivery, but the idea of gold nanoparticles that target a specific cell type (eg. tumor) look promising. Gold nanoparticles infused with a synthetic genetic circuit could be introduced into the human body, whereby it will become incorporated and localized to a patient's tumor. Upon delivery of the gold nanoparticles' cargo, herein the novel circuit, we could light activate the circuit by shining light, thus producing highly localized cytotoxicity to the tumor. Such a process could be engineered to combat other medical needs, such as aging, tissue regeneration, neurodegenerative diseases, etc or be used to allow easier non-invasive studying of cellular response in large-scale systems.
Our project will consist of 3 main components:
When designing the circuit, our main consideration will be that the circuit is modular and a wide variety of outputs can be hooked up to it, maximizing the potential benefits. Another consideration is that it's orthogonal and translates well to a wide variety of cell types and does not interfere with the cell too much, although since we're actively aiming to control and reprogram the cell for therapeutic reasons, we don't have to worry about system interference too much.
Delivery to cells will be a big challenge, as many current methods are insufficient or very toxic to the cells and unrealistic (lipofectamine, nucleofection). Hopefully, our usage of emerging nanoparticle delivery systems will allow our delivery mechanism to be efficient. Potentially there will be synergy as well, as gold nanoparticles have been shown to have potential therapeutic effects by themselves.
Finally, we will have to consider how we will verify that our system is actually working. This will probably consist of in vitro assays of individualized circuit parts, followed by characterization of our circuit as a whole. Finally, we will need some way to make sure the delivery method actually works before loading our circuit onto it.
- Chow, B. Y., & Boyden, E. S. (2011). Synthetic Physiology. Science, 332(6037), 1508-1509. http://www.sciencemag.org/content/332/6037/1508.summary.
This is a nice perspective on the potential applications of optigenetics, especially in relation to physiological applications. They examine how the delivery of a payload could be regulated through a light-sensitive melanopsin-NFAT signaling cascade, which is one of the potential approaches we could take in our genetic circuit.
- Kleinlogel, S., Feldbauer, K., Dempski, R. E., Fotis, H., Wood, P. G., Bamann, C., & Bamberg, E. (2011). Ultra light-sensitive and fast neuronal activation with the Ca2+-permeable channelrhodopsin CatCh. Nature neuroscience, 14(4), 513-8. http://www.nature.com/neuro/journal/v14/n4/full/nn.2776.html.
In this paper, they develop a variant of the traditional rhodopsin protein, which is activated by light, that is over 70 times more sensitive to light than the wild-type protein. This is of particular interest to our circuit, which needs a way to quickly respond to light. They characterize their optimized rhodopsin protein in the paper, which gives an idea of the different assays we could use to test our system to see if it actually responds to light.
- Poon Z, Lee JB, Morton SW, Hammond PT. (2011). Controlling in vivo stability and biodistribution in electrostatically assembled nanoparticles for systemic delivery. Nano Letters, 11(5), 2096-103. http://pubs.acs.org/doi/pdf/10.1021/nl200636r.
From the Hammond lab, another nanoparticle paper! Here, they talk about the generation of LbL (layer-by-layer) nanoparticles to deliver drugs to tumors more effectively. In short, they designed nanoparticles with different “shells” that can actively seek, bind tightly, and desposit their drug cargo in the most efficient manner.
- von Maltzahn G, Park JH, Lin KY, Singh N, Schwöppe C, Mesters R, Berdel WE, Ruoslahti E, Sailor MJ, Bhatia SN. (2011). Nanoparticles that communicate in vivo to amplify tumour targeting. Nat Materials, 10(7), 545-52. http://www.nature.com/nmat/journal/v10/n7/pdf/nmat3049.pdf.
From the Bhatia lab, they describe a cool “biomaterials” approach to targeting cancer cells. More specifically, they engineer signaling modules (nanoparticles or engineered proteins) to target tumors, and activate coagulation cascade that recruits clot-targeted nanoparticles in circulation that either carries a diagnostic or has a therapeutic cargo. A “2CS” if you will, with a sensor that homes the tumor, and a responder that activates a very localized drug delivery or diagnostic.
- Ye, H., Daoud-El Baba, M., Peng, R.-W., & Fussenegger, M. (2011). A synthetic optogenetic transcription device enhances blood-glucose homeostasis in mice. Science, 332(6037), 1565-8. http://www.ncbi.nlm.nih.gov/pubmed/21700876.
In this paper, they expressed a genetic circuit in diabetic mice that expressed a glucagon-like peptide in response to blue light. This is especially interesting as they tested their construct both in vitro and in vivo, showing the potential robustness of such a genetic circuit in an actual application. In addition, their circuit is a new approach to combating diabetes, showing the power of light-based clinical applications.
Langer lab, siRNA delivery with gold http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2728206/
DNA Delivery with polymers http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3044603/
Antibody conjugation http://www.jnanobiotechnology.com/content/5/1/4
Layer by Layer gold nanoparticle assembly for siRNA http://pubs.acs.org/doi/pdf/10.1021/nl9003865
UV release of DNA from gold nanoparticles https://people.chem.umass.edu/cmartin/Pubs/PDF/Han_PhotoReleaseAu_Angew06.pdf
Review on gold nanoparticles and cancer therapeutics http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&sqi=2&ved=0CEUQFjAB&url=http%3A%2F%2Fwww.dovepress.com%2Fgetfile.php%3FfileID%3D3421&ei=uEbaTqbSAq-62gXQnZDrAw&usg=AFQjCNE2o0vIyNmMI7gFxwYzC_Md7mA51A&sig2=vgVPFKMVLTHz6YNdgq8R4w