Puma, a pro-apoptotic gene, as a novel molecular biomarker for tnfalpha-induced human islet damage

Abstract

p53-upregulated modulator of apoptosis (PUMA) is a biomarker associated with islet cell health. If PUMA is low, islet cells are typically healthy. If PUMA is high, islet cells are typically unhealthy or dying. PUMA may be measured by either measuring its nucleic or amino acid. PUMA mRNA may be induced by TNF-α stimulation in a time- and dose-dependent manner and β cell apoptosis is induced through a mitochondrial pathway. TNF-α significantly inhibited glucose-induced preproinsulin precursor mRNA synthesis. Such β cell stress signaling in human islets indicates overall state of islet health and, ultimately, the risk of onset and/or degree of severity of both type 1 and type 2 diabetes mellitus.

1 . A method for measuring the health of an islet cell, comprising measuring the level of p53 upregulated modulator of apoptosis (PUMA), wherein the level of PUMA is inversely proportional to the health of the islet cell. 
     
     
         2 . The method of  claim 1 , wherein the level of PUMA is measured by quantifying the amount of nucleic acid encoding PUMA expressed by the islet cell. 
     
     
         3 . The method of  claim 2 , wherein the nucleic acid is PUMA mRNA and wherein the level of BBC3 mRNA is also quantified. 
     
     
         4 . The method of  claim 1 , wherein tumor necrosis factor-α level is positively correlated to the level of PUMA in the islet cell. 
     
     
         5 . The method of  claim 1 , wherein the level of PUMA is measured by stimulating islet cells with TNF-α alone or in combination with interferon gamma. 
     
     
         6 . The method of  claim 1 , wherein a high level of PUMA indicates an increased risk or severity of diabetes in a subject that produced the islet cell. 
     
     
         7 . The method of  claim 6 , wherein the diabetes is type 1 diabetes mellitus or type 2 diabetes mellitus. 
     
     
         8 . The method of  claim 1 , wherein a low level of PUMA indicates a healthy islet cell. 
     
     
         9 . The method of  claim 1 , wherein the level of PUMA is a factor in determining whether the islet cell is a candidate for transplant. 
     
     
         10 . The method of  claim 1 , further comprising testing the level of one or more proinflammatory cytokines, wherein a low PUMA level combined with a low or undetectable level of one or more of tumor necrosis factor-α, interleukin-1β, interferon-γ, oxygen free radicals, or nitric oxide indicates good islet cell health. 
     
     
         11 . A method protecting an islet cell from apoptosis comprising administering a JAK inhibitor to the islet cell. 
     
     
         12 . The method of  claim 11 , wherein the method further comprises administering a tyrosine kinase inhibitor to the islet cell. 
     
     
         13 . The method of  claim 12 , wherein the tyrosine kinase inhibitor is Imatinib. 
     
     
         14 . A screen for a compound that protects islet cell health, comprising:
 (a) administering the compound to an islet cell;   (b) after a time sufficient for the compound to affect the level of PUMA in the islet cell, taking a measurement of the level of PUMA in the islet cell and comparing that measurement to either a first measurement taken before the administration of the compound or a known PUMA level; wherein, if the level of PUMA in the cell has decreased after administration of the compound, then the compound protects islet cell health.   
     
     
         15 . The screen of  claim 14 , wherein the level of PUMA is measured after both the compound and TNF-α are administered to the islet cell, and wherein, if the level of PUMA does not increase, the compound protect the islet cells from TNF-α mediated islet damage. 
     
     
         16 . The screen of  claim 14 , wherein the PUMA nucleic acid or amino acid is measured. 
     
     
         17 . The screen of  claim 14 , further comprising administering the compound to the islet cell more than once and taking additional PUMA measurements over time to develop a time and dosing course for the compound. 
     
     
         18 . The screen of  claim 14 , wherein a compound found to protect islet health is administered in a pharmaceutically effective carrier and dose to a patient for the treatment of diabetes. 
     
     
         19 . The screen of  claim 14 , wherein the compound is a TNF-α receptor blocker. 
     
     
         20 . The screen of  claim 19 , wherein the compound is Etanercept.