NeuroD1 dynamics in adult rat pineal gland

CASTRO AE; SAVASTANO LE; FITT MR; MUÑOZ EM

Huerta Grande. Córdoba.

Congreso; II Reunión conjunta en Neurociencias; 2010

NeuroD1 protein dynamics in the adult rat pineal gland Castro A.E., Savastano L.E., Fitt M.R. and Muñoz E.M. Laboratory of Neurobiology: Chronobiology Section, IHEM-CONICET, School of Medical Sciences, National University of Cuyo, Mendoza, Argentina. ANPCyT. NeuroD1 is a transcription factor involved in the differentiation and functional maintenance of specific endocrine and neuronal cells, including rodent pinealocytes [1]. Several affected transcripts were identified in neonatal pineal gland from NeuroD1 KO mice using microarray analysis [1]. In contrast to mRNA levels [1], the NeuroD1 protein could exhibit circadian variations in the adult rat pineal gland. Via immunohistochemistry, we studied the expression of pineal NeuroD1 protein over a 12:12 L:D cycle. We observed a NeuroD1 signal in pinealocytes and vimentin-positive astrocytes. While NeuroD1 was cytoplasmic in all positive cells and nuclear in a few vimentin-positive cells during the light phase, at ZT14 NeuroD1 was found in both subcellular compartments in pinealocytes and astrocytes. During early night, the disruption of the circadian system via superior cervical ganglionectomy sequestered NeuroD1 into the pinealocyte cytoplasm. Furthermore, using phalloidin and an anti-actin antibody we observed abundant actin filaments at night vs. globular actin during day time. These results suggest that NeuroD1 might modulate adult pinealocyte functions in a circadian fashion; the actin cytoskeleton might be involved. Reference [1] Muñoz et al. 2007. J Neurochem 102(3): 887-899.