Induction of insulin secretion in engineered liver cells by nitric oxide

Latha Muniappan,Sabire Özcan

doi:10.1186/1472-6793-7-11

Abstract

BackgroundType 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.ResultsExpression 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.ConclusionLiver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.

Highlights

Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin
In this study we demonstrate that the expression of human insulin or the beta-cell specific transcription factors Pancreatic Duodenum Homeobox protein-1 (PDX-1), v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) and Neurogenic Differentiation 1 (NeuroD1) in the Hepa1-6 liver cell line or in primary liver cells using adenoviral gene transfer, results in production and secretion of insulin
Hepa1-6 liver cells transfected with an adenoviral vector containing human insulin are able to produce and secrete insulin To test whether liver cells can be engineered to produce and secrete insulin in a regulated manner, we have incubated the Hepa1-6 liver cell line with an adenovirus expressing human insulin

Summary

Introduction

Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. Pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. Defects in insulin production and secretion, as observed in type 1 diabetes due to autoimmune destruction of the pancreatic beta cells, result in chronic hyperglycemia, which is responsible for most of the secondary complications associated with diabetes. Because of the lack of insulin production, gene therapy using surrogate beta cells is a potential approach in the treatment of Type 1 diabetes [1,2,3]. Successful therapy for Type 1 diabetes requires that mature insulin be produced and secreted from surrogate beta-cells in a glucose-regulated manner. Liver appears to be an excellent surrogate organ for production of insulin,

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