Latest revision as of 16:22, 26 October 2020

Exendin-4 (GLP-1 analogue) with secretion signal

Exendin-4 is an analogue of H. suspectum to human GLP-1. Here with secretion signal (KR 1020120130606-A/1: Secretion signal peptide linked Exendin-4 gene transduced pancreatic islet cluster for treatment of type I diabetes). It is known to increase the release of Insulin from beta cells of the pancreas.

Background

In the iGEM Team Tübingen 2019 project, Exendin-4 was used as a therapeutic for the treatment of Type 2 Diabetes mellitus with probiotics. Exendin-4 is, in contrast to its human analogue more stable and not as easily degraded by DPP-IV peptidase. Thus, a suitable candidate for a therapeutic.

Usage and Biology

Exendin-4 is used as a treatment for Type 2 Diabetes mellitus. Its human analogue gLP-1 originates from the prepeptide proglucagon, which is cleaved into, among others, GLP-1 (1-37) by prohormone convertase 1 (PC1) (Lim et al. 2006). The inactive GLP-1 (1-37) is then processed into its active form GLP-1 (7-37) by an endopeptidase. This active form is secreted and diffuses across the basal lamina and enters the lamina propria, where it is taken up into the capillaries, reaching the circulatory system (Lim et al. 2006).The glucagon like peptide binds to a GPCR on the pancreatic beta cells, which will cause an intracellular cascade activating an Adenylate Cyclase. If ATP is available within the cell, which means if the cell has already taken up sugar and run through glycolysis, cAMP will be produced (Jens Juul Holst, 2007). Overall, this will result in prolonged depolarization and calcium ion influx and consequently more secretion of insulin from the beta cells (Jens Juul Holst, 2007). This increase in insulin secretion can overcome the relative lack of insulin in the periphery of Type 2 Diabetes mellitus(Jens Juul Holst, 2007).

Exendin-4 and GLP-1 do not only have a direct effect on the pancreas, but also decrease gastrointestinal motility and secretion, hunger and the emptying of the stomach, thus helping in weight reduction (Jens Juul Holst, 2007). Additionally, they are considered to be cardioprotective(Jens Juul Holst, 2007). This is very important for the therapy, since many cases of Type 2 DM are caused by an unhealthy lifestyle and obesity(Jens Juul Holst, 2007).

IISER_Bhopal 2020

(Author: Priya Sharma)

Exendin-4 was discovered in the venom of a poisonous lizard known as Gila monster (Heloderma suspectum) and was similar in both structure and function to GLP-1. The Exendin-4 molecule is resistant to dipeptidyl peptidase. It has a half-life of about 26 minutes in humans after intravenous infusion which is significantly higher than the half-life of active GLP-1 molecule (1–2 minutes) in humans. [5] The PI3K/Akt/mTOR pathway is closely related to development of resistance to enzalutamide treatment in prostate cancer cells. The pathway is activated in response to enzalutamide treatment of prostate cancer cells. Exendin-4 suppresses the PI3K/Akt/mTOR pathway and inhibits the growth of prostate cancer cells. [6] Exendin‐4 antagonizes enzalutamide induced invasion and migration of prostate cancer cells thus alleviated resistance to enzalutamide. Exendin‐4 along with enzalutamide might prove more effective for patients with advanced prostate cancer. [7]

We added the stop codon and codon optimized the existing sequence for expression in Escherichia coli (Part name: BBa_K3450020).

Sequence and Features

References

1. Holst, Jens Juul. The physiology of glucagon-like peptide 1. Physiological reviews 87.4 (2007): 1409-1439.
2. KR 1020120130606-A/1: Secretion signal peptide linked Exendin-4 gene transduced pancreatic islet cluster for treatment of type I diabetes
3. Lim, Gareth E., Brubaker, Patricia L. Glucagon-Like Peptide 1 Secretion by the L-Cell. (2006). 10.2337/db06-S020. Diabetes. p. S70-S77
4. Copley, Kathrin, et al. "Investigation of exenatide elimination and its in vivo and in vitro degradation." Current drug metabolism 7.4 (2006): 367-374.
5. Simonsen, L., Holst, J.J. & Deacon, C.F. Exendin-4, but not glucagon-like peptide-1, is cleared exclusively by glomerular filtration in anaesthetised pigs. Diabetologia 49, 706–712 (2006). https://doi.org/10.1007/s00125-005-0128-9
6. He W, Li J. Exendin-4 enhances radiation response of prostate cancer. The Prostate. 2018;1–9. https://doi.org/10.1002/pros.23687
7. He W, Shao Y, Yu Y, Huang W, Feng G, Li J. Exendin‐4 enhances the sensitivity of prostate cancer to enzalutamide by targeting Akt activation. The Prostate. 2020;1–9. https://doi.org/10.1002/pros.23951