Distribution of bone morphogenetic protein and bone morphogenetic protein receptor transcripts in the rodent nervous system and up-regulation of bonemorphogenetic protein receptor type II in hippocampal dentate gyrus in a rat model of global cerebral ischemia

Bone morphogenetic proteins belong to the transforming growth factor-p supe rfamily and act through serine/threonine kinase type I and type II receptor s such as bone morphogenetic protein receptor type I and type II. In order to further understand the roles that these factors exert in the nervous sys tem, we have examined the expression pattern of seven bone morphogenetic pr oteins and bone morphogenetic protein receptor type I and II transcripts in the brain and spinal cord of rodent. Whereas bone morphogenetic protein re ceptor type I expression was low in rat brain, in situ hybridization studie s performed with specific digoxigenin-labelled riboprobes revealed the pres ence of bone morphogenetic protein receptor type II-positive cells througho ut the brain, with a notable localization in dopaminergic cells of the subs tantia nigra. Bone morphogenetic protein receptor type Il transcripts were also expressed by large motoneuron-like cells located in the ventral horn o f the spinal cord and by sensory neurons of dorsal root ganglia. In additio n, we observed a significant up-regulation of bone morphogenetic protein re ceptor type II in the granule cells of the dentate gyms 48 h after transien t global cerebral ischemia in rat suggesting that modulation of this recept or intervenes during neuronal plasticity or repair that occur upon brain in jury. Among the potential ligands for this receptor, bone morphogenetic pro tein-6 and bone morphogenetic protein-7 were expressed in meninges and the choroid plexus, while bone morphogenetic protein-4-expressing cells were sp atially and temporally regulated in myelinated structures during developmen t and in the adult suggesting its expression in oligodendrocytes. These data clearly indicate that besides their roles in bone and embryonic tissues, bone morphogenetic proteins and their receptors may have also impo rtant functions in adult neural tissues. (C) 2000 IBRO. Published by Elsevi er Science Ltd. All rights reserved.