Related Experiment Video
Updated: Sep 26, 2026
A Single Cell Dissociation Approach for Molecular Analysis of Urinary Bladder in the Mouse Following Spinal Cord Injury
Published on: June 17, 2020
Human RPE cell lysis of extracellular matrix: functional urokinase plasminogen activator receptor (uPAR), collagenase
Susan G Elner1, Victor M Elner, Andrei L Kindzelskii
1Department of Ophthalmology, University of Michigan, Kellogg Eye Center, Ann Arbor, MI 48105, USA.
Abstract:
Age-related macular degeneration (ARMD), proliferative vitreoretinopathy (PVR) and uveitis are characterized by RPE motility through the ECM of retinal lesions. The purpose of this study was to test the hypothesis that multiple proteolytic systems are functionally intact at the HRPE surface and peri-cellular region and that these activities are differentially modulated by IL-1beta. HRPE cells were evaluated: (1). as individual cells or cell extracts, (2). during migration across three-dimensional ECM-like layers and (3). in tissue sections. The urokirase plasminogen activator receptor (uPAR; CD87) was detected on HRPE cells as well as its functional activity. Although uPAR was associated with CD11b (CR3) on live resting cells, polarized migratory HRPE cells were found to dissociate uPAR from CR3; uPAR then translocated to anterior pole of the cell, where it enhanced PAI-1-inhibitable local proteolytic activity. The relative contribution of uPAR and collagenase in HRPE migration was evaluated using three-dimensional gelatin matrices. Interestingly, uPAR/uPA was found to play a key role in migration across these layers. IL-1 upregulated uPAR, collagenase, and elastase activities, suggesting that cytokines may affect the invasive program of HRPE cells in vivo. Immunohistochemistry for uPAR was performed in sections of human retina. Immunoreactive uPAR was present along the HRPE basolateral membrane in retinal sections and in sections of diseased retinal tissue at an enhanced level. Our results suggest that multiple proteolytic systems are present in association with HRPE and that the uPAR/uPA system may be particularly important.
Insights
The study found that the urokinase plasminogen activator receptor (uPAR) system plays a key role in retinal pigment epithelial cell migration. This system is upregulated by IL-1beta, suggesting its involvement in retinal diseases.
Area of Science:
- Ocular surface biology
- Cellular and Molecular Ophthalmology
- Retinal disease mechanisms
Background:
- Age-related macular degeneration (ARMD), proliferative vitreoretinopathy (PVR), and uveitis involve retinal pigment epithelial (HRPE) cell migration through the extracellular matrix (ECM).
- Understanding the proteolytic systems governing HRPE cell motility is crucial for elucidating disease pathogenesis.
Purpose of the Study:
- To investigate the presence and function of proteolytic systems at the HRPE cell surface.
- To determine how interleukin-1 beta (IL-1beta) modulates these proteolytic activities.
- To test the hypothesis that multiple proteolytic systems are intact and differentially regulated by IL-1beta.
Main Methods:
- HRPE cells were analyzed individually, during migration across 3D ECM-like layers, and in tissue sections.
- Urokinase plasminogen activator receptor (uPAR) expression and activity were assessed.
- Three-dimensional gelatin matrices were used to evaluate the role of uPAR and collagenase in migration.
- Immunohistochemistry was performed on human retinal sections.
Main Results:
- uPAR was detected on HRPE cells and exhibited functional activity, translocating to the cell's leading edge during migration.
- The uPAR/urokinase plasminogen activator (uPA) system was found to be critical for HRPE cell migration across 3D matrices.
- IL-1beta upregulated uPAR, collagenase, and elastase activities in HRPE cells.
- Immunoreactive uPAR was observed on the basolateral membrane of HRPE cells in normal and diseased retinal tissues.
Conclusions:
- Multiple proteolytic systems are associated with HRPE cells.
- The uPAR/uPA system plays a significant role in HRPE cell migration.
- Cytokines like IL-1beta can modulate HRPE cell invasive behavior, potentially impacting retinal disease progression.
Related Concept Videos
01:23Role of Matrix Metalloproteases in Degradation of ECM
A...
01:29The Extracellular Matrix
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.
Composition of the Extracellular Matrix
The extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse...