Abstract
Purpose :
To characterize the secretion of matrix metalloproteases (MMPs) and tissue inhibitors of matrix metalloproteases (TIMPs) by induced pluripotent stem cell- derived Retinal Pigment Epithelium (iPS-RPE) during wound healing. iPS-RPE displays the phenotype and functions of in vivo retinal pigment epithelium (RPE), and provides a physiologically relevant cell type to study disease mechanisms. iPS-RPE was used to develop an in vitro wound healing model. We hypothesize that iPS-RPE secretes mediators of tissue remodeling such as MMPs and TIMPs that promote migration and proliferation of cells during wound healing.
Methods :
iPS-RPE was grown on transwells until fully confluent and pigmented. The monolayers were scratched to induce a wound. Cell culture media were collected from both the apical and basolateral sides of the transwells every 72 hours for 12 days. The media were analyzed by multiplex ELISA assays to detect secreted MMPs and TIMPS. Activity assays were performed to detect activated forms of MMP-2 and TIMP-1 in the conditioned media from the wounded monolayers.
Results :
MMP-2 and TIMP-1, -2, -3, and -4 were detected in the culture media from iPS-RPE. The proteins were found to be secreted in a polarized manner. Increased levels of MMP-2 were detected in media from the apical side of wounded cells. Increased levels of TIMPs were detected in culture media from both the apical and basolateral sides of wounded cells. The secretion of MMP-2 was elevated from Days 3-12 after wounding of the monolayer. MMP-2 activity was also increased from Days 3 -12 after wounding. Secretion of all four TIMPs increased within 3 days after wounding and peaked at Day 6. TIMP-1 activity was increased from Days 3-12 after wounding.
Conclusions :
These results indicate that iPS-RPE secretes MMP-2 and all four TIMPS in a polarized manner. After wounding of the monolayer, apical secretion of MMP-2 was significantly higher compared to control. After wounding of the monolayer, apical secretion of all four TIMPs increased compared to control, while only TIMP-1 and -3 showed increased basolateral secretion compared to control.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.