20.109(F12) Pre-Proposal: Viral mitigation of insulin resistance
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One of the hallmark characteristics of obesity and Type 2 diabetes is insulin resistance
One of the hallmark characteristics of obesity and Type 2 diabetes is insulin resistance, a peptide the insulin resistance. Here, we that the of synthetic system antibodies resistininsulin resistance and development of Type 2 diabetes.
Revision as of 08:27, 29 November 2012
- Stanley Gill
- Amy Liu
- T/R 20.109 Lab
- Team Yellow
Title of Proposed Project
Antibody-based Regulation of Resistin Levels through a Synthetic Circuit Injected via Vector Immunoprophylaxis
One of the hallmark characteristics of obesity and Type 2 diabetes is insulin resistance, and data across many papers suggests that a peptide called resistin is responsible for the increase in insulin resistance. Here, we wish to use vectored immunoprophylaxis, a technique that involves gene therapy, to introduce a synthetic biological system which can regulate levels of resistin in the body. When an abnormally high level of resistin is present, the synthetic system will activate expression of the injected gene and induce muscles cells in mice to secrete antibodies targeting resistin, which will hopefully lower insulin resistance and prevent further development of obesity and Type 2 diabetes.
Previous research has shown a strong positive correlation between the resistin protein level and insulin resistance, suggesting that high levels of resistin may be the cause of insulin resistance, which also commonly coexists with obesity and Type II diabetes (Steppan 2002, Sanchez-Solana 2012). A previous study by Balazs et al. has also shown that genes encoding for specific antibodies can be injected into the muscle tissue of mice through a technique called vectored immunoprophylaxis (VIP). VIP uses adeno-associated virus to transfer the genes into muscle cells, where the genes can then be expressed and neutralizing antibodies can be secreted into the blood circulation (Balazs 2012). Exploring the possibility of using gene therapy and antibodies to reduce excess levels of resistin in the body may significantly reduce insulin resistance and help elucidate the relationship between between resistin and obesity and Type II diabetes.
References: 1. Balazs, A.B., Chen, J., Hong, C.M., Rao, D.S., Yang, L. and Baltimore, D. Antibody-based protection against HIV infection by vectored immunoprophylaxis. Nature 481:81-84 (2012).
2. Steppan, C.M. and Lazar, M.A. Resistin and obesity-associated insulin resistance. Trends Endocrinol Metab 13:18–23 (2002).
3. Sanchez-Solana, B., Laborda, J., and Baladron, V. Mouse resistin modulates adipogenesis and glucose uptake in 3T3-L1 preadipocytes through the ROR1 receptor. Mol Endocrinol 26:110-127 (2012).
Personal health is of great concern to today's society, especially in relation to weight loss. The rate of Type 2 diabetes in the human population has increased alongside the rate of obesity; it has been clear for some time that excessive weight gain can lead to insulin resistance which is a direct cause of Type 2 diabetes. Presently, the accepted method of prevention and alleviation of obesity and its related ailments is diet and exercise. Drug based weight-loss methods have not been exhaustively explored; of the drugs that have been explored, very few act directly on the adipose cells and the products they secrete. Because mouse adipocytes have been implicated in accelerating the development of insulin resistance through the production of resistin and because increased levels of resisitin can be found in humans that are insulin resistant, the formation of a new therapy that targets resistin could be beneficial in preventing and/or reducing the degree of insulin resistance in any given individual.
Our experiment aims to test if neutralization of resistin via a humoral response can effectively slow the onset of and/or treat insulin resistance in mice. This will be done using a synthetically created system inserted into muscle cells via immunoprophylaxis. The synthetic system will be self regulating and will turn on only when there is an excess of Resistin. When on, the system will produce monoclonal antibodies for resistin when the levels reach a certain threshold, the antibodies will bind to the resistin and prevent it from binding to one of the several receptors of its downstream effectors (such as the receptor ROR1) that may lead to insulin resistance. Upon introducing the system into mice that already show symptoms similar to type 2 diabetes, we hope that this potentially long acting therapy will result a decrease in resistin in the blood as well as a decrease in insulin resistance. We will test over long periods of time (up 90 days) to monitor how the resistin levels in the blood change at certain time points after the therapy is introduced. We will also periodically perform insulin tests (inject the mice with insulin, test how long they take to stabilize to baseline levels) to get gauges of how resistant the mice are, if at all to the insulin test while being treated with the synthetic system. If we can confirm that downregulating the activity of resistin reduces the level of resistin in the blood and has an effect on insulin resistance, there may be potential for using this therapy for insulin resistance in humans as well.