Islet neogenesis-associated protein (INGAP): Its positive modulatory role in insulin secretion

FLORES LE; DEL ZOTTO HH; FRAGAPANE F; MAIZTEGUI B; ROMÁN C; BOSCHERO AC; GAGLIARDINO JJ

REGULATORY PEPTIDES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 192 p. 30 - 34

0167-0115

Islet neogenesis-associated protein (INGAP) enhances β-cell secretory function and mass increasing islet neogenesis and reducing β-cell apoptosis. We have currently studied the potential modulatory role of INGAP in insulin secretion using two different experimental approaches. Glucose stimulated insulin secretion (GSIS) was studied in hamster islets transfected with INGAP-small interfering RNA (INGAP-siRNA). In parallel, freshly isolated islets were incubated with high glucose and the same concentration of either a specific anti-INGAP rabbit serum or normal rabbit serum. INGAP-siRNA transfected islets decreased by 35.4% and 47.2% their INGAP mRNA and protein content and lowered its GSIS by 25.8%. When INGAP-PP was added to the culture medium of INGAP-siRNA transfected islets they enhanced its GSIS at the same level of control islets. INGAP antibody in the medium also decreased significantly the GSIS (37%). These results indicate that INGAP plays a positive modulatory role in insulin secretion; thus, its addition to islets maintained in culture previous to their transplant could optimize their secretory function