: Glaucoma is the leading cause of blindness worldwide. It is a genetic disease, but usually not monogenic. PITX2 is a transcription factor which affects the development of the eye, and mutations in its encoding gene are a common cause of Axenfeld-Rieger syndrome (ARS). As ARS is often accompanied with glaucoma, it is reasonable to consider that Malfunction of PITX2 or its target genes may contribute to glaucoma. NOMO that encodes NODAL modulator 2 was among earlier identified PITX2 target genes. NODAL signaling is a form of TGFB signaling, and TGFB signaling is an important glaucoma related pathway. MicroRNAs are important components in the regulation of most normal and abnormal biological processes. We aimed in this study to identify miRNAs that may affect the expression of PITX2, and NOMO, NODAL, SMAD2 and SMAD3. SMAD2 and SMAD3 are downstream components of NODAL signaling

In silico searches were performed to identify miRNAs that may target above genes. Among the miRNAs, we focused on fourteen that are expressed in the trabecular meshwork or that have otherwise been associated with glaucoma. The trabecular meshwork is a glaucoma relevant tissue because it affects intraocular pressure. The effects of the miRNAs were assessed using a luciferase dual assay in HEK293 cells transfected with the miRNAs and with vectors in which 3'UTR segments of the genes were cloned downstream of coding sequences of a luciferase encoding gene.

In silico searches predicted four, one, three, thirteen, and seven miRNAs that may, respectively, target NODAL, PITX2, NOMO, SMAD2 and 7 SMAD3. The luciferase assays confirmed the predicted effects on the 3'UTR of most of the target genes, including all predicted to affect NODAL, PITX2, NOMO

Results of earlier experiments suggested that functions of PITX2 and TGFB signaling molecules may have relevance to glaucoma. Most recently, NOMO has also been implicated. Here, we have presented evidence that certain miRNAs may target these molecules and/or related molecules. Further studies will elucidate the potential roles of these miRNAs in the etiology of glaucoma.