Diabetes Mellitus affects roughly 1 in 10 people globally . Type 2 Diabetes (T2D) comprises around 90% of all diabetes cases and is primarily a result of insulin resistance . In just our team of 15 undergraduates, all of us are one degree of separation from someone with T2D. Our friends and family with T2D are forced to endure expensive medications and administer multiple daily injections and finger pricks.
Moreover, the burden of diabetes is disproportionately borne by lower income groups , and even more so in countries that do not have medical infrastructure equipped to offer adequate treatment . We believe that healthcare is a human right. This prompted our mission to execute a project using the resources and privileges we have to make a global human impact among resource constrained communities.
On average, diabetic patients spend $9,601 (USD) annually on T2D care and have over twice the overall medical cost compared to non-diabetic individuals . The price of diabetes care has exhibited a steep increase while T2D rates are simultaneously growing by a projected fifty percent in the next thirty years . The expensive nature of treatment in combination with the concerning spread of T2D sparked the urgency for our project. The motivation for pursuing Helo is deeply rooted in the lack of global access to T2D care.
Chronic complications associated with T2D include heart failure, kidney disease, lower-limb amputations, blindness, and neuropathy . Of all associated complications, 50 to 85% are preventable by treatment and medication . Glucagon-Like Peptide 1 (GLP-1) Receptor Agonists (GLP-1 RA), such as Exendin-4 (Ex-4), are one of the leading forms of T2D treatment but can cost upwards of $800 (USD) a month within the U.S. . Increasing access to effective diabetes treatments can broadly improve human health and particularly benefit communities suffering from the inequitable distribution of diabetes therapeutics. This is what inspired our project: Helo.
Glucagon-like Peptide 1 is an incretin hormone that is naturally released by intestinal L-cells in response to a rise in blood glucose levels to regulate insulin production . GLP-1s bind to human GLP-1 receptors (GLP-1 R) found on pancreatic beta cells and activate adenylyl cyclase which converts ATP into cyclic adenosine monophosphate (cAMP). Increased levels of cAMP cause insulin to be released from pancreatic beta cells. GLP-1 is degraded by dipeptidyl peptidase-4 (DPP-4) enzymes and has an average half-life of two minutes in vivo.
Ex-4 is a 39 amino acid peptide originally derived from the salivary glands of the Gila Monster (Heloderma suspectum) and consists of a single alpha helix . Ex-4 is resistant to degradation by DPP-4, thus resulting in a longer half-life of around 30 minutes in vivo. The longer half-life of Ex-4 in combination with its competitive binding against native GLP-1 serves as an effective mechanism to increase both insulin production and sensitivity for T2D patients .
We propose that Ex-4 can be naturally produced in Saccharomyces cerevisiae (S. cerevisiae), commonly known as baker's yeast, as a functional and cost-effective pharmaceutical treatment. As S. cerevisiae is Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration (FDA) , we hypothesize bioencapsulated S. cerevisiae containing Ex-4 can be administered orally to bypass degradation in the stomach and avoid the need for subcutaneous injections . Our goal is to produce a cost-effective T2D therapeutic that can be propagated in as little as one square meter and distributed for local communties to grow.
We used Escherichia coli (E. coli) as a basis for Ex-4 production while simultaneously pursuing S. cerevisiae as a therapeutic host. Golden Gate Assembly (GGA) was employed to construct the Ex-4 plasmids that were transformed into E. coli and S. cerevisiae respectively. For S. cerevisiae, genomic integration of the Ex-4 gene was accomplished by homologous recombination. After integration and induced expression, Immobilized Metal Affinity Chromatography (IMAC) was used to isolate Ex-4. SDS-PAGE results indicated the presence of Ex-4 in both S. cerevisiae and E. coli. Finally, we plan to conduct a binding affinity assay with our recombinant GLP-1 R and our Ex-4 to confirm functionality.