Expression of bone morphogenetic proteins (BMP), BMP receptors, and BMP associated proteins in human trabecular meshwork and optic nerve head cells and tissues

Purpose: Bone morphogenetic proteins (BMPs) are multi-functional cytokines that have wide ranging effects on a variety of cells and tissues. In the present study, we profile the expression of BMPs, BMP receptors, and BMP associated proteins in the human trabecular meshwork (TM) and optic nerve head (ONH), two tissues involved in glaucoma pathogenesis. Methods: Total RNA was isolated and subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) to examine the expression of BMP, BMP receptor, and BMP associated proteins in tissues and cultured cells from the human TM and ONH (ONH astrocytes and lamina cribrosa cells). Western immunoblotting was used to study the expression of BMP and BMP receptor proteins in cultured human TM and ONH cells. Results: Both TM and ONH cells and tissues expressed mRNAs for BMP2, BMP4, BMP5, BMP7, BMP-RIA, BMP-RIB, BMP-RII, DRM(gremlin), follistatin, chordin and NMA (BAMBI). The proteins for BMP2, BMP4, BMP5, BMP7, and all three BMP receptors were expressed in cultured human TM and ONH cells. Conclusions: Members of the BMP family of genes, including BMPs, BMP receptors, and inhibitory BMP associated proteins are expressed in the human TM and ONH. These molecules may be involved in the normal formation and function of these tissues. Altered expression of members of this gene family may lead to functional changes in the TM and ONH. These genes and their respective signaling pathways merit further research to examine their possible role in glaucoma.