iGEM 2012

Hepatitis C

We designed a device for the therapy of hepatitis C, composed of microencapsulated mammalian cells that include a genetic bistable toggle switch with a positive feedback loop, where in one state the cells produce interferon alpha (IFN-α) as the antiviral effector and in the second state they produce hepatocyte growth factor (HGF) to promote liver regeneration.

A pharmacokinetic model demonstrated that if the device is implanted into the liver it results in higher levels of IFN-α within the liver than systemically. More importantly, this type of application avoids the spikes of high IFN-α concentration that occur in treatment with IFN-α injections. This should decrease the severity of side effects of IFN-α experienced by a high percentage of patients.

We estimated, based on the detection of IFN-α produced by HEK293 cells, that sufficient quantities of the therapeutic protein could be produced by the amount of microencapsulated cells feasible in a real therapeutic application.

Figure 1. Therapy of hepatitis C by microencapsulated cells which can be regulated to produce and release therapeutic proteins into the liver tissue.

Figure 2. Scheme of the constructs for the regulated therapy of hepatitis C with interferon alpha (IFN-α) and hepatocyte growth factor (HGF). Each of the therapeutic effector is released in equimolar amount to the autoactivator.

Hepatitis C virus infection

Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) which primarily infects the liver. Hepatitis C is a serious worldwide health problem with a prevalence of 3% in the world’s population. According to WHO, 170 million individuals are infected with an incidence of 3 to 4 million new cases per year. More than 350,000 people die yearly from hepatitis C-related diseases. In the US the HCV has surpassed HIV as a cause of death. Medical care costs associated with treatment of HCV infection are estimated to be more than $600 million per year just in the USA.

References

Banfi, A., von Degenfeld, G., Gianni-Barrera, R., Reginato, S., Merchant, M.J., McDonald, D.M., and Blau, H.M. (2012) Therapeutic angiogenesis due to balanced single-vector delivery of VEGF and PDGF-BB. FASEB J. 26, 2486-2497.

Ortiz, L.A., Dutreil, M., Fattman, C., Pandey, A.C., Torres, G., Go, K., and Phinney, D.G. (2007) Interleukin 1 receptor antagonist mediates the antiinflammatory and antifibrotic effect of mesenchymal stem cells during lung injury. Proc. Natl. Acad. Sci. U S A 104, 11002-11007.

Szymczak, A.L., Workman, C.J., Wang, Y., Vignali, K.M., Dilioglou, S., Vanin, E.F., Vignali D.A. (2004) Correction of multi-gene deficiency in vivo using a single 'self-cleaving' 2A peptide-based retroviral vector. Nat. Biotechnol. 22, 589-94.

---

Next: Ischaemic heart disease >>