Professor Paola S. Timiras (Emerita)

Department of Molecular and Cell Biology

Dr. Timiras' laboratory has conducted research actively for many years in the field of neuroendocrinology. Her previous studies have focused on the effect of hormones on brain activity and metabolism. Neuroendocrinology investigates both the role of the central nervous system (CNS) in regulating hormonal function and, reciprocally, the role of hormones in directing the development and maturation of the brain (organizational actions of hormones) as well as its metabolic and behavioral functions. The research of Dr. Timiras' laboratory has been concerned primarily with the latter aspect of neuroendocrine relationship.

Currently, Dr. Timiras' laboratory is investigating the effect of hormones on the development, maturation, and aging of glial cells and the role of these cells on the normal and abnormal function of the brain. Glial cells are more numerous than neurons and have several metabolic essential functions as well as being responsible for myelination. Glial cells are grouped into neuroglial cells (astrocytes and oligodendrocytes with the same embryonal origin as neurons) and into microglial cells (representing the immune cells of the brain).

Several steroid hormones (estrogen, progesterone, glucocorticoids) have been shown to decrease proliferative activity of the glial cells while accelerating their maturation, thereby affording a certain degree of protection to the neurons during development and aging. They also display a protective action against cytotoxic effects of substances (such as the excitatory neurotransmitter glutamate). Neuroglial cells can be made to proliferate by the administration of various local growth factors. As the cells proliferate they undergo a change to less mature cells that may be considered equivalent progenitor cells and therefore capable of differentiation in either neurons or glial cells (depending on the conditions of the microenvironment). This type of investigation holds a promise for the identification of local progenitor cells and the possibility of stimulating (by hormones) their differentiation and maturation in adult competent cells.