Oral Delivery of Pentameric Glucagon-Like Peptide-1 by Recombinant Lactobacillus in Diabetic Rats.
Glucagon-like peptide-1 (GLP-1) is an incretin hormone produced by intestinal cells and stimulates insulin secretion from the pancreas in a glucose-dependent manner. Exogenously supplied GLP-1 analogues are used in the treatment of type 2 diabetes. An anti-diabetic effect of Lactobacillus in lowering plasma glucose levels and its use as a vehicle for delivery of protein and antibody fragments has been shown previously. The aim of this study was to employ lactobacilli as a vehicle for in situ production and delivery of GLP-1 analogue to normalize blood glucose level in diabetic GK (Goto-Kakizaki) rats. In this study, we designed pentameric GLP-1 (5×GLP-1) analogues which were both expressed in a secreted form and anchored to the surface of lactobacilli. Intestinal trypsin sites were introduced within 5×GLP-1, leading to digestion of the pentamer into an active monomeric form. The E. coli-produced 5×GLP-1 peptides delivered by intestinal intubation to GK rats resulted in a significant improvement of glycemic control demonstrated by an intraperitoneal glucose tolerance test. Meanwhile, the purified 5×GLP-1 (trypsin-digested) from the Lactobacillus cultures stimulated insulin secretion from HIT-T15 cells, similar to the E. coli-produced 5×GLP-1 peptides. When delivered by gavage to GK rats, non-expressor L. paracasei significantly lowered the blood glucose level but 5×GLP-1 expression did not provide an additional anti-diabetic effect, possibly due to the low levels produced. Our results indicate that lactobacilli themselves might be used as an alternative treatment method for type 2 diabetes, but further work is needed to increase the expression level of GLP-1 by lactobacilli in order to obtain a significant insulinotropic effect in vivo.
Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden.
Yin
http://orcid.org/0000-0001-6294-8241
Y
Lin
Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden.
Kasper
K
Krogh-Andersen
Department of Molecular Medicine and Surgery, Rolf Luft Research Center for Diabetes and Endocrinology, M1:03 Karolinska University Hospital, Karolinska Institutet, Stockholm SE-17176, Sweden.
Julien
J
Pelletier
Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden.
Harold
H
Marcotte
Department of Molecular Medicine and Surgery, Rolf Luft Research Center for Diabetes and Endocrinology, M1:03 Karolinska University Hospital, Karolinska Institutet, Stockholm SE-17176, Sweden.
Claes-Göran
CG
Östenson
Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden.
Lennart
L
Hammarström
D000284:Administration, Oral; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D016503:Drug Delivery Systems; D004926:Escherichia coli / Q000378:metabolism; D005247:Feeding Behavior; D052216:Glucagon-Like Peptide 1 / Q000008:administration & dosage* / Q000627:therapeutic use*; D005951:Glucose Tolerance Test; D007279:Injections, Subcutaneous; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007778:Lactobacillus / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus; D019151:Peptide Library; D051381:Rats; D011995:Recombination, Genetic / Q000235:genetics; D015203:Reproducibility of Results; D014170:Transformation, Genetic; D014357:Trypsin / Q000378:metabolism
D001786:Blood Glucose; D007328:Insulin; D019151:Peptide Library; D052216:Glucagon-Like Peptide 1; D014357:Trypsin