Cells genetically modified to comprise pancreatic islet glucokinase and uses thereof

Abstract

The present invention relates generally to a population of cells genetically modified to comprise pancreatic islet glucokinase and capable of producing insulin in a glucose responsive manner and uses thereof. More particularly, the present invention relates to a population of cells so genetically modified capable of producing insulin in response to physiologically relevant levels of glucose and uses thereof. The cells of the present invention are useful in a wide variety of applications, in particular in the context of therapeutic and prophylactic regimes directed to the treatment of diabetes and/or the amelioration of symptoms associated with diabetes, based on the transplantation of the cells of the present invention into mammals requiring treatment. Also facilitated is the design of in vitro based screening systems for testing the therapeutic effectiveness and/or toxicity of potential adjunctive treatment regimes.

1 . A genetically modified mammalian cell, which cell is capable of secreting insulin or functional fragment or homologue thereof, said genetic modification comprising the transfection of said cell with a nucleic acid molecule encoding pancreatic islet glucokinase or functional fragment or homologue thereof and wherein said cell is not a pancreatic β cell. 
     
     
         2 . The genetically modified cell of  claim 1  wherein said mammalian cell is a human cell. 
     
     
         3 . The genetically modified cell of  claim 1 , wherein said cell is a hepatocyte capable of secreting insulin. 
     
     
         4 . The genetically modified hepatocyte of  claim 3 , wherein said hepatocyte is capable of secreting insulin due to its transfection with a nucleic acid molecule encoding insulin or functional fragment or homologue thereof. 
     
     
         5 . The genetically modified hepatocyte of  claim 4  wherein said hepatocyte is an Huh7ins cell. 
     
     
         6 . The genetically modified hepatocyte of  claim 3  wherein said hepatocyte expresses glucokinase in response to an extracellular glucose concentration in the rang of 3-8 mM. 
     
     
         7 . The genetically modified hepatocyte of  claim 6  wherein said hepatocyte expresses glucokinase in response to an extracellular glucose concentration in the rang of 3.5-7 mM. 
     
     
         8 . The genetically modified hepatocyte of  claim 7  wherein said hepatocyte expresses glucokinase in response to an extracellular glucose concentration in the rang of 4-6 mM. 
     
     
         9 . The genetically modified hepatocyte of  claim 8  wherein said hepatocyte expresses glucokinase in response to an extracellular glucose concentration in the rang of 4-5 mM. 
     
     
         10 . The genetically modified hepatocyte of  claim 3  wherein said pancreatic islet glucokinase is human pancreatic islet glucokinase. 
     
     
         11 . The genetically modified hepatocyte of  claim 10  wherein said pancreatic islet glucokinase is the form encoded by SEQ ID NO:2 or is a functional fragment thereof. 
     
     
         12 . The genetically modified hepatocyte of  claim 11  wherein said genetic modification comprises the transfection of said hepatocyte with a vector, which vector expresses SEQ ID NO:2 or a functional fragment thereof. 
     
     
         13 . The genetically modified hepatocyte of  claim 12  wherein said vector is a bicistronic vector. 
     
     
         14 . The genetically modified hepatocyte of  claim 13  wherein said bicistronic vector is pIRESpuro3. 
     
     
         15 . The genetically modified hepatocyte of  claim 14  wherein said bicistronic vector corresponds substantially to SEQ ID NO:3. 
     
     
         16 . The genetically modified hepatocyte of  claim 14  wherein said hepatocyte is an Huh7ins cell. 
     
     
         17 . A method of therapeutically or prophylactically treating a condition in a mammal, which condition is characterised by the aberrant production of functional insulin, said method comprising introducing into said mammal an effective number of the genetically modified cells according to  claim 1 . 
     
     
         18 . (canceled) 
     
     
         19 . The method of  claim 17  wherein said mammal is a human. 
     
     
         20 . The method of  claim 17  wherein said aberrant production of functional insulin is an inadequate production of functional insulin. 
     
     
         21 . The method of  claim 20  wherein said inadequate production of functional insulin is an inadequate production of functional insulin in response to an extracellular glucose concentration of greater than 3 mM. 
     
     
         22 . The method of  claim 21  wherein said glucose concentration is 4-8 mM. 
     
     
         23 . The method of  claim 22  wherein said glucose concentration is 4-6 mM. 
     
     
         24 . The method of  claim 17  wherein said condition is diabetes. 
     
     
         25 . The method of  claim 24  wherein said diabetes is type 1 diabetes, IDDM, gestational diabetes, slowly progressive IDDM, latent autoimmune diabetes or type 2 diabetes. 
     
     
         26 . A method of reducing glucose levels in a mammal said method comprising introducing into said subject an effective number of the genetically modified cells according to  claim 1 . 
     
     
         27 . The method according to  claim 26  wherein said mammal is a human.