2008 — 2012 |
Chan, Matilda Frances |
K08Activity Code Description: To provide the opportunity for promising medical scientists with demonstrated aptitude to develop into independent investigators, or for faculty members to pursue research aspects of categorical areas applicable to the awarding unit, and aid in filling the academic faculty gap in these shortage areas within health profession's institutions of the country. |
The Role of Extracelluar Enzymes in Regulating Corneal Repair @ University of California San Francisco
[unreadable] DESCRIPTION (provided by applicant): Corneal opacification affects millions of people and is the second leading cause of blindness in the world. A clear need exists for the development of non-surgical strategies to prevent and treat corneal fibrosis and the subsequent development of corneal opacification. Previous and preliminary studies show that extracellular enymes including the 6-O-sulfatase Sulf-1 and matrix metalloproteinases (MMPs) including MMP-9 and MMP-12 are expressed in the cornea only upon injury, implicating their possible roles in corneal repair. These enzymes are produced by epithelial, stromal and inflammatory cells, and their roles in corneal repair c have not been well-studied. In the epithelium, MMP-9 appears to decrease re-epithelialization through its effects on the TGF pathway, while in the stroma MMP-12 has been shown to be protective against fibrosis via TGF-p in various other disease processes. In addition, MMP-12's ability to produce angiostatin more efficiently than other MMPs suggests that it might play a role in preventing corneal angiogenesis. Sulf-1 has been found to modulate the binding of growth factors and chemokines in vitro. Stimulation of various growth factors, particularly TGF-p2 and FGF, are critical to the corneal fibrotic phenotype and corneal neovascularization. Taken together, these extracellular enzymes may regulate various aspects of the repair process, both positively and negatively. In this application, we propose to investigate the roles of the extracellular enzymes MMP-9, MMP-12, and Sulf-1 in the epithelial, stromal, and inflammatory corneal response to injury. Specific Aim 1 will determine the effects of MMP-9 or Sulf-1 activity on the epithelial cell proliferation response to injury. Specific Aim 2 will use MMP-12 knockout mice to examine the role of MMP- 12 in fibrosis and angiogenesis during the corneal stromal response to injury. Specific Aim 3 will examine the ability of these extracellular enzymes to recruit inflammatory cells to the cornea and will use a novel imaging technique based on spinning disk confocal microscopy to study inflammatory cell dynamics in the cornea in vivo and in real-time. Understanding the roles of extracellular enzymes in wounded corneas should further our understanding of the mechanisms important to the maintenance of corneal clarity and provide basic insights that will, in the long term, allow for the development of better treatment of corneal opacification. [unreadable] [unreadable] [unreadable]
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0.976 |
2013 — 2017 |
Chan, Matilda Frances |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Regulation of Corneal Repair by Metalloproteinases @ University of California, San Francisco
PROJECT SUMMARY Corneal opacification affects millions of people and is the second leading cause of blindness in the world. The effective medical treatment of vision-threatening corneal opacification is a major unmet clinical challenge. Injury is a major cause of corneal opacification and can occur by a variety of mechanisms including infectious and noninfectious ulcers, incisional and laser surgery, and trauma. Following injury, proteinases regulate aspects of the repair process including inflammation, neovascularization, and remodeling. Excessive proteolysis resulting in corneal scarring has been associated with loss of corneal clarity. The matrix metalloproteinases (MMPs) represent the most prominent family of proteinases associated with corneal wound repair in humans. It has long been appreciated that tissue destruction and corneal pathology following corneal injury is associated with excessive proteolytic activity mediated by MMPs. However, potential protective effects of MMPs in the repair response are underappreciated. We have found that MMP12 (macrophage metalloelastase) is expressed in injured corneas and has a protective effect on corneal fibrosis during wound repair. Our preliminary data show that MMP12 protects against corneal stromal myofibroblast transformation, that MMP12 blunts the corneal angiogenic response to injury via regulation of VEGFA expression, and that MMP12 inhibits the accumulation of macrophages in wounded corneas via regulation of CCL2 expression. Collectively, these data demonstrate a protective role of MMP12 in the fibrotic, neovascular, and inflammatory responses to corneal injury. Furthermore, our findings suggest MMP12 as an important factor needed for the maintenance of corneal clarity following injury. Given these findings, we hypothesize that MMP12 regulation of CCL2 expression is a common mechanism by which MMP12 inhibits inflammation and neovascularization. This hypothesis will be addressed in the experiments of the following Specific Aims: (1) to define the role of MMP12 in the regulation of expression of CCL2 and CCR2; (2) to determine the interplay of MMP12 and CCL2 in the regulation of corneal neovascularization; and (3) to characterize MMP12 expression and activity levels in patient corneal samples. This combination of molecular and translational approaches will provide novel insight into the mechanisms by which MMP12 protects against corneal fibrosis and will open the possibility of developing novel modalities aimed at preventing and treating pathological fibrosis in human patients.
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0.976 |
2021 |
Chan, Matilda F Gestwicki, Jason E (co-PI) [⬀] |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Analysis of Chemical Modulators For Corneal Endothelial Dystrophies @ University of California, San Francisco
PROJECT SUMMARY Corneal endothelial dystrophies are a common cause of vision loss and are characterized by a slowly progressive, bilateral dysfunction of the corneal endothelium. The main therapeutic option to restore vision in these patients remains corneal transplantation, as medical management is usually inadequate. Mutations in the SLC4A11 gene are associated with several endothelial dystrophies, including Fuchs endothelial corneal dystrophy (FECD), congenital hereditary endothelial corneal dystrophy (CHED), and Harboyan syndrome. SLC4A11 is a transporter protein that functions to maintain osmotic balance in corneal endothelium, and many point mutations in SLC4A11 found in disease lead to misfolding of the full-length protein. There is recent evidence that assisting mutant SLC4A11 to regain proper folding is a promising therapeutic approach. A prior small-scale, high throughput chemical screen identified the non-steroidal anti-inflammatory drug glafenine for its ability to correct folding defects in misfolded SLC4A11, and following correction the mutant SLC4A11 protein regained functional activity. Though glafenine is not a candidate for clinical use due to anaphylaxis and renal toxicity, its efficacy supports an approach using other small molecule folding correctors to repair defective SLC4A11 in corneal endothelial dystrophies. Our long-term objective is to develop first-in-class therapeutics for patients with vision impairment due to protein misfolding in the cornea. We propose to test the hypothesis that compounds identified through phenotypic screening assays will promote the correct folding of mutant SLC4A11 and restore corneal endothelial cell function. The goals of this proposal are to: Aim 1) Perform focused screening to identify correctors of SLC4A11 folding; Aim 2) Perform large, unbiased chemical library and genetic screening to identify novel targets and mechanisms; and Aim 3) Assess cytotoxic effects of NSAIDs on corneal cells. Using advanced experimental methods, including high-content microscopy-based screening assays and novel CRISPR-based genetic screens, the proposed studies will provide insight into the correction of protein folding defects as a therapeutic strategy for corneal endothelial dystrophies. Results from the study will be used to develop a new, non-surgical treatment option for patients with vision loss due to corneal endothelial dystrophies and establish a novel therapeutic approach to corneal disease.
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0.976 |