Background: Insulin deficiency is currently treated with pharmacological insulin secretagogues, insulin injections or islet transplants. Secondary failure of pharmacological agents is common; insulin injections often fail to achieve euglycemic control; and islet transplants are rare. Non-β cells capable of regulated insulin secretion in vivo could be a functional cure for diabetes. Hepatocytes are good candidates, being naturally glucose-responsive, protein-secreting cells, while the liver is positioned to receive direct nutrient signals that regulate insulin production. Methods: Human liver-derived Chang cells were modified with a plasmid construct in which a bifunctional promoter comprising carbohydrate response elements and the human metallothionein IIA promoter controlled human proinsulin cDNA expression. Secretory responses of stable cell clones were characterized in vitro and in vivo by proinsulin radioimmunoassay. Results: Transfected Chang cells secreted 5-8 pmol proinsulin/ 106 cells per 24 h in continuous passage for at least a year in response to 5-25 mM glucose and 10-90 μM zinc in vitro. Glucose and zinc synergistically increased proinsulin production by up to 30-fold. Non-glucose secretagogues were also active. Glucose transporter 2 (GLUT2) and glucokinase cDNA co-transfection enhanced glucose responsiveness. Intraperitoneally implanted Chang cells secreted proinsulin in scid and Balb/c mice. Serum proinsulin levels were further increased 1.3-fold (p<0.05) after glucose and 1.4- to 1.6-fold (p<0.005) after zinc administration in vivo. Conclusions: These results are the first to demonstrate stable proinsulin production in a human liver-derived cell line with activity in vitro and in vivo and provide a basis for engineering hepatocytes as in vivo bioimplants for future diabetes treatment. Copyright © 2002 John Wiley & Sons, Ltd.

Item Type:	Refereed Article
Keywords:	Diabetes; Glucose-inducible; Hepatocyte; Zinc-inducible; carbohydrate; complementary DNA; glucokinase; glucose; glucose transporter 2; proinsulin; zinc; proinsulin; animal experiment; article; cell based gene therapy; cell clone; controlled study
Research Division:	Medical and Health Sciences
Research Group:	Medical Biochemistry and Metabolomics
Research Field:	Medical Biochemistry: Nucleic Acids
Objective Division:	Health
Objective Group:	Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:	Diabetes
Author:	Patil, JG (Dr Jawahar Patil)
ID Code:	96249
Year Published:	2002
Web of Science® Times Cited:	9
Deposited By:	NC Ports and Shipping
Deposited On:	2014-10-28
Last Modified:	2014-11-25
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