2001 Fiscal Year Final Research Report Summary
Effect of pseudomonal virulence factors on the induction of corneal matrix metalloproteinases
| Project/Area Number |
12671713
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Ophthalmology
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| Research Institution | Kumamoto University |
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Principal Investigator |
YONEMURA Takaharu Kumamoto University, Ophthalmology, Faculty member, 医学部附属病院, 助手 (20332877)
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| Co-Investigator(Kenkyū-buntansha) |
KIMURA Akira Kumamoto University, Ophthalmology, Assistant Professor, 医学部附属病院, 講師 (20284771)
HIRATA Akira Kumamoto University, Ophthalmology, Assistant Professor, 医学部附属病院, 講師 (60295144)
FUKUSHIMA Mikiko Kumamoto University, Ophthalmology, Faculty member, 医学部附属病院, 助手 (10284770)
MIYAJIMA Seiya Kumamoto University, Ophthalmology, Faculty member, 医学部, 助手 (10336208)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Pseudomonas aeruginosa / keratitis / matrix metalloproteinase / pseudomonal elastase / alkaline protease / exotoxin A / lipopolysaccharide / corneal stromal cells / proinflammatory cytokines |
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| Research Abstract |
The pathogenesis of pseudomonal keratitis was investigated by focusing on induction and activation of matrix metalloproteinases(MMPs) by pseudomonal virulence factors and proluflammatory cytokines. Corneal lesions and MMP induction in vivo were evaluated in rabbit corneas infected with a clinical isolate of Pseudomonas aeruginosa. Effects of pseudomonal virulence factors [elastase, alkaline protease, exotoxin A and lipoporysaccharide (LPS)], tumor necrosis factor (TNF)-α and interleukin (IL)-1β on MMP induction and activation were further examined in vitro in rabbit corneal fibroblasts (RCF) and human fibrosarcoma (HT1080) cells using reverse transcriptase-polymerase chain reaction (RT-PCR), zymography and immunoblotting. Corneal ulcers with typical ring abscesses were observed 12-24 h after infection, and MMPs, particularly MMP-9, were upregulated in infected corneas. Pseudomonal elastase caused the most extensive damage to both cell types. PCF treated with pseudomonal exoproteases or LPS expressed and secreted MMP-9. Exotoxin A had no effect on MMP expressioa Both IL-1β and TNF-α augmented MMP-9 released from the cells. In conclusion, corneal destruction seen with P. aeruginosa infections may result from enhanced expression of MMPs by corneal stromal cells stimulated with pseudomonal exoproteases and proinflammatory cytokines and the proteolytic activation of MMPs by pseudomonal elastase.
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