Title: The Pathway of IRF6 Using Salivary Glands and Pancreas
Sameer Bilal (Presenter)
University of Houston
Walid Fakhouri, University of Texas School of Dentistry
Objectives: IRF6 is a member of the IRF family of transcription factors. IRF6 encodes for transcription factors that regulates expression of interferons critical for immune functions and biological processes during craniofacial development. Although the regulative role of IRF6 has been confirmed in epithelial, immune, and erythropoiesis pathways, its mechanism of regulation in osteoblastic differentiation remain unknown. Mutations in IRF6 cause VWS and PPS and contribute to the risk of CLP. IRF6 null mice are born with abnormal craniofacial structures as compared to mice with IRF6 and they show a loss of mucous acini in salivary glands and large spatial arrangement between acinar cells in pancreas. The aim of this project was to determine the pathway of IRF6 by detecting the level of interacting and downstream targets using IHC. The expression of MMP2, MMP3 and AQP5 was detected in salivary gland and pancreas.
Methods: Got sections of the salivary gland and pancreas samples to be used in our study. Performed H&E and IHC staining for the antibodies MMP2, MMP3 and AQP5 on the wild type and IRF6 null samples obtained from sectioning. Ages of the specimens used were E15.5, E17.5 and P0.
Results: H&E staining showed a clear difference in terms of cell organization and helped us differentiate between wild type and IRF6 null samples. The salivary glands in IRF6 null mice were disorganized and had almost no mucous acinar cells. In IRF6 null pancreas, abnormal morphology was observed. The nuclei was on the apex as compared to the wild type pancreas where it was generally in the center of the cytosol. The antibodies tested were expressed in the cytosol in wild type pancreas, had almost no expression in mutant cells and were expressed only in the acini for wild type salivary glands, were not expressed in mutant cells.
Conclusions: Our findings indicate IRF6 is critical in the development of salivary glands and pancreas. These results suggest that DNA variations in IRF6 cause risk of salivary gland and pancreatic disorders in humans. Antibodies expressed in the wild type cells suggest a regulatory role of IRF6 in extra-cellular matrix. Our future goal is to find out more branches in the IRF6 pathway and translate these findings into the clinic to identify genetic risk factors in patients with salivary gland and pancreas disorders.