Oral Delivery of Glucagon Like Peptide-1 by a Recombinant Lactococcus lactis
To develop a live oral delivery system of Glucagon like peptide-1 (GLP-1), for the treatment of Type-2 Diabetes.
LL-pUBGLP-1, a recombinant Lactococcus lactis (L. lactis)) transformed with a plasmid vector encoding GLP-1 cDNA was constructed and was used as a delivery system. Secretion of rGLP-1 from LL-pUBGLP-1 was characterized by ELISA. The bioactivity of the rGLP-1 was examined for its insulinotropic activity on HIT-T15 cells. Transport of rGLP-1 across MDCK cell monolayer when delivered by LL-pUBGLP-1 was studied. The therapeutic effect of LL-pUBGLP-1 after oral administration was investigated in ZDF rats.
DNA sequencing and ELISA confirmed the successful construction of the LL-pUBGLP-1 and secretion of the active form of rGLP-1. In vitro insulinotropic studies demonstrated that LL-pUBGLP-1 could significantly (p < 0.05) stimulate HIT-T15 cells to secrete insulin as compared to the controls. When delivered by LL-pUBGLP-1, the GLP-1 transport rate across the MDCK cell monolayer was increased by eight times (p < 0.01) as compared to the free solution form. Oral administration of LL-pUBGLP-1 in ZDF rats resulted in a significant decrease (10–20%, p < 0.05) in blood glucose levels during 2–11 h post dosing and a significant increase in insulin AUC0-11h (2.5 times, p < 0.01) as compared to the free solution.
The present study demonstrates that L. lactis when genetically modified with a recombinant plasmid can be used for the oral delivery of GLP-1.
KEY WORDSGLP-1 L. lactis normal flora oral protein delivery type-2 diabetes
Glucagon like peptide-1
- L. lactis
Lactococcus lactis sub sp. lactis
Lactococcus lactis transformed with pUB1000 plasmid
Lactococcus lactis transformed with pUBGLP-1 plasmid
M17 growth media supplemented with 5% glucose
Expression host plasmid vector
Recombinant plasmid with GLP-1 c-DNA
recombinant GLP-1 secreted extracellularly by LL-pUBGLP-1
Type 2 Diabetes mellitus
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