Induction of insulin secretion in engineered liver cells by nitric oxide.
BACKGROUND
Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs in a glucose-independent manner. In the present study we engineered liver cells to produce and secrete insulin and insulin secretion can be stimulated via the nitric oxide pathway.


RESULTS
Expression of either human insulin or the beta cell specific transcription factors PDX-1, NeuroD1 and MafA in the Hepa1-6 cell line or primary liver cells via adenoviral gene transfer, results in production and secretion of insulin. Although, the secretion of insulin is not significantly increased in response to high glucose, treatment of these engineered liver cells with L-arginine stimulates insulin secretion up to three-fold. This L-arginine-mediated insulin release is dependent on the production of nitric oxide.


CONCLUSIONS
Liver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.
Muniappan
Latha
L
Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, 741 South Limestone, BBSRB, Lexington, KY 40536, USA. latha.muniappan@uky.edu
Ozcan
Sabire
S
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001698:Biomedical Engineering / Q000379:methods; D002460:Cell Line; D002478:Cells, Cultured; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D051473:Maf Transcription Factors, Large / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D001120:Arginine; D051792:Basic Helix-Loop-Helix Proteins; D018398:Homeodomain Proteins; D007328:Insulin; D051473:Maf Transcription Factors, Large; D009569:Nitric Oxide; D015534:Trans-Activators; C485159:MAFA protein, human; C093970:NEUROD1 protein, human; C084010:pancreatic and duodenal homeobox 1 protein