INCREASED EXPRESSION OF CALBINDIN D-28K VIA HERPES-SIMPLEX VIRUS AMPLICON VECTOR DECREASES CALCIUM-ION MOBILIZATION AND ENHANCES NEURONAL SURVIVAL AFTER HYPOGLYCEMIC CHALLENGE

Disruption of Ca2+ homeostasis often leads to neuron death. Recently, the function of calcium-binding proteins as neuronal Ca2+ buffers has been debated, We tested whether calbindin D-28k functions as an in tra cellular Ca2+ buffer by constructing bicistronic herpes simplex virus vectors to deliver rat calbindin cDNA to hippocampal neurons in vitro. Neurons were infected with vectors delivering calbindin or a negative control or were mock-infected. After 12 or 24 h of hypoglycemia, infe cted cells were made aglycemic during fura-2 calcium ratiometric imagi ng, In response to this challenge, neuronal overexpressing calbindin h ad less Ca2+ mobilized as compared with negative controls or mock-infe cted cells. Cells were assayed for survival after 12- or 24-h hypoglyc emia or aglycemia. The calbindin vector decreased neuronal death due t o hypoglycemia but not aglycemia. Here we demonstrate, in response to hypoglycemic challenge, both decreased Ca2+ mobilization and increased survival of cells infected with the calbindin vector.