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Expression of membrane type-4 matrix metalloproteinase (metalloproteinase-17) by human eosinophils
Marie-Christine Gauthier1, Christine Racine, Claudine Ferland
1Institut Universitaire de Cardiologie et de Pneumologie de l'Université Laval, Que., G1V 4G5, Sainte-Foy, Canada.
Abstract:
Circulating eosinophils need proteinases to mediate a spatially limited and orientated digestion of the extracellular matrix and to migrate into tissue. Moreover, proteinases are likely involved in tissue remodeling, a crucial feature of chronic diseases including asthma. Eosinophils express matrix metalloproteinase (MMP)-9, which is increased upon stimulation with TNF-alpha. Other MMPs, the membrane type (MT)-MMPs, likely play a major role in cell invasion and tissue remodeling. MT4-MMP was identified in peripheral blood leukocyte preparations, but it is not known whether eosinophils express MT4-MMP. We investigated the expression of MT4-MMP and its modulation by TNF-alpha in purified human blood eosinophils. The constitutive expression of MT4-MMP mRNA was detected by RT-PCR in unstimulated eosinophils, lymphocytes, and monocytes, but not neutrophils. Stimulation of eosinophils with TNF-alpha increased MT4-MMP mRNA expression. This effect appeared at 4h and reached a maximum at 8h of incubation. MT4-MMP protein was detected in freshly isolated blood eosinophils by Western blotting and immunocytochemistry. TNF-alpha increased expression of the MT4-MMP protein. MT4-MMP protein was also detected in nasal polyp eosinophils by immunohistochemistry. In conclusion, eosinophils constitutively express MT4-MMP, which is increased upon stimulation with TNF-alpha. Consequently, MT4-MMP may be directly involved in the degradation of extracellular matrix components and/or modulate the activity of other proteins implicated in eosinophil migration and tissue remodeling.
Insights
Eosinophils express membrane type 4 matrix metalloproteinase (MT4-MMP), an enzyme involved in tissue remodeling. Tumor necrosis factor-alpha (TNF-alpha) increases MT4-MMP expression in eosinophils, suggesting a role in chronic inflammatory diseases.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Eosinophils utilize proteinases for extracellular matrix digestion and tissue migration.
- Proteinases are implicated in tissue remodeling, a hallmark of chronic diseases like asthma.
- Eosinophils express matrix metalloproteinase (MMP)-9, with levels rising upon TNF-alpha stimulation.
Purpose of the Study:
- To investigate the expression of membrane type 4 matrix metalloproteinase (MT4-MMP) in human blood eosinophils.
- To determine if TNF-alpha modulates MT4-MMP expression in eosinophils.
Main Methods:
- Reverse transcription polymerase chain reaction (RT-PCR) to detect MT4-MMP mRNA.
- Western blotting and immunocytochemistry to detect MT4-MMP protein.
- Stimulation of purified human blood eosinophils with TNF-alpha.
Main Results:
- Constitutive MT4-MMP mRNA expression was found in eosinophils, lymphocytes, and monocytes, but not neutrophils.
- TNF-alpha stimulation significantly increased MT4-MMP mRNA and protein expression in eosinophils.
- MT4-MMP protein was also detected in nasal polyp eosinophils via immunohistochemistry.
Conclusions:
- Human eosinophils constitutively express MT4-MMP.
- TNF-alpha upregulates both MT4-MMP mRNA and protein in eosinophils.
- MT4-MMP may play a direct role in extracellular matrix degradation and modulate eosinophil functions in tissue remodeling and migration.