EXPRESSION OF MESSENGER-RNAS OF MULTIPLE GROWTH-FACTORS AND RECEPTORSBY NEURONAL CELL-LINES - DETECTION WITH RT-PCR

Neurons and glia are capable of both secreting and responding to a lar ge variety of growth factors. However, information on multiple express ion of growth factors and their receptors was usually obtained from un correlated observations, using cells from various animals of origin, d evelopmental stages, growth phases, culture ages and culture condition s. Because of its specificity and extreme sensitivity, reverse transcr iption-polymerase chain reaction (RT-PCR) is uniquely suitable to stud y a large panel of growth factors and their receptors from a limited c ell sample, free of these intervening variables. In this paper we eval uate the expression of mRNA of a total of 35 growth factor-related pro teins by conducting RT-PCR on three neuronal cell lines: the PC12 rat pheochromocytoma line, the MAH rat sympathoadrenal progenitor line, an d the N18 mouse neuroblastoma line. Three types of results are present ed. The first confirms the existing knowledge such as the presence of Trk-A (NFG receptor) in PC12. The second consists of new information t hat expands and extends earlier observations, such as the presence of CNTF receptor complex in PC12, which explains our previous report that CNTF enhances the biological effects of NGF on these cells. The third consists of novel information that leads the way to further experimen tation by the more conventional methods. These include the strong expr ession of Trk-B by MAH, predicting the biological responsiveness of MA H to BDNF and NT-4, and the expression of CNTF receptor in N18. Our re sults also suggest that CNTF is an autocrine factor for PC12 and MAH, since both lines express the growth factor as well as the receptor. Th us, RT-PCR is a valuable tool in growth factor research that can be us ed in complement to, and interactively with, other approaches such as bioassay, receptor binding, and immunochemical determination. It will be particularly useful for screening a large number of growth factors in minute areas of the brain in patients suffering from neurodegenerat ive diseases such as Parkinson's and Alzheimer's.