Canonical Wnt signaling in optic nerve head

Purpose: While canonical Wnt signaling has been explored in areas of the eye like the trabecular meshwork and ciliary body during glaucomatous pathology, it has not been explored in the lamina cribrosa. Complement protein 1, subunit q (C1q) has been shown to be an activator of the canonical Wnt pathway leading to an increase in fibrosis in various tissues, but not explored in the lamina cribrosa (LC) either. As C1q concentration increases in blood serum and central nervous system with an increase in age, C1q activation of canonical Wnt signaling may be an important factor in glaucomatous pathology. Therefore, we aimed to prove that a functional canonical Wnt signaling pathway is expressed in the lamina cribrosa and that C1q is an activator of the pathway. Methods: Primary mouse optic nerve head (ONH) astrocytes from C57BL/6J mice were cultured and characterized. When confluent, cells were serum starved overnight and then treated for 24 hours with 100 nM Wnt3a or left untreated as a control. Following treatment, cells were collected and had cytosolic and nuclear fractions separated. Fractions were then western blotted and probed for β-Catenin. Bands were analyzed via densotometry and fold changes in expression were compared to control cells. Results: In a single primary mouse ONH astrocyte cell strain, β-Catenin expression increased 1.354-fold when treated with 100 nM Wnt3a compared to control in the cytosolic fraction and 1.145-fold when treated with 100 nM Wnt3a compared to control in the nuclear fraction. Without additional cell strains, statistical significance is not able to be determined. Conclusions: Our very preliminary results support our hypothesis that a functional canonical Wnt signaling pathway is expressed in the LC. Additional cell strains will need to be examined to fully determine presence of a functional canonical Wnt signaling pathway as well as determining if C1q activates the pathway in this population.