Oral glucagon-like peptide 1 analogue ameliorates glucose intolerance in db/db mice

Objectives We constructed a recombinant oral GLP-1 analogue in Lactococcus lactis (L. lactis) and evaluated its physiological functions. Results In silico docking suggested the alanine at position 8 substituted with serine (A8SGLP-1) reduced binding of DPP4, which translated to reduced cleavage by DPP4 with minimal changes in stability. This was further confirmed by an in vitro enzymatic assay which showed that A8SGLP-1 significantly increased half-life upon DPP4 treatment. In addition, recombinant L. lactis (LL-A8SGLP-1) demonstrated reduced fat mass with no changes in body weight, significant improvement of random glycemic control and reduced systemic inflammation compared with WT GLP-1 in db/db mice. Conclusion LL-A8SGLP-1 adopted in live biotherapeutic products reduce blood glucose in db/db mice without affecting its function.