Peptide Binding Glucose Regulated Protein 78 Improves Type 1 Diabetes by Preventing Pancreatic β Cell Apoptosis.
OBJECTIVE
Diabetes Type 1 is characterized by hyperglycemia due to reduced insulin secretion that results from the death of pancreatic β cells. It was suggested that endoplasmic reticulum (ER) stress is associated with the autoimmune-mediated β cell destruction. Glucose regulated protein 78 (GRP78) functions as a key regulator to maintain the ER function. Under stress conditions GRP78 is up-regulated and expressed on the cell surface serving as a signaling receptor. Our first objective was to examine the effects of peptide binding cell surface GRP78 to reduce the deleterious effects of diabetes induced by streptozotocin. The second objective was to demonstrate the ability of the peptide to protect the pancreatic β cells from apoptosis.


METHODS
The effect of ADoPep on weight loss, HbA1c levels and anti GRP78 antibody titers was evaluated in a diabetes mouse model. The effect of ADoPep on the pancreatic β Ins1E cell apoptosis was determined by FACS analysis.


RESULTS
The administration of ADoPep to diabetic mice retained the weight loss and reduced HbA1c significantly in 60% of mice. Titers of anti GRP78 antibodies increased in 70% of the treated mice. Apoptosis was significantly inhibited in stressed pancreatic β Ins 1E cells.


CONCLUSIONS
We demonstrate that administration of the peptide ADoPep to diabetic mice improved type 1 diabetes by preventing pancreatic β cell apoptosis.
Felsenstein Medical Research Center, Rabin Medical Center, Beilinson Campus, Petach Tikva 49100, Israel.
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Raiter
The Jesse Z and Sara Lea Shafer, Institute for Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
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Tenenbaum
The Jesse Z and Sara Lea Shafer, Institute for Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
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Yackobovitch-Gavan
Felsenstein Medical Research Center, Rabin Medical Center, Beilinson Campus, Petach Tikva 49100, Israel.
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Battler
Felsenstein Medical Research Center, Rabin Medical Center, Beilinson Campus, Petach Tikva 49100, Israel.
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Hardy
D051722:ADAM Proteins / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL
D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse; D008565:Membrane Proteins; D051722:ADAM Proteins; C490902:Adam15 protein, mouse