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Published on: June 26, 2018
Establishment of an MT4-MMP-deficient mouse strain representing an efficient tracking system for MT4-MMP/MMP-17
Akiko Rikimaru1, Kiyoshi Komori, Takeharu Sakamoto
1Division of Cancer Cell Research, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, 108-8639, Japan.
Abstract:
The biological functions of membrane-type 4 matrix metalloproteinase (MT4-MMP/MMP-17) are poorly understood because of the lack of a sensitive system for tracking its expression in vivo. We established a mutant mouse strain (Mt4-mmp(-/-)) in which Mt4-mmp was replaced with a reporter gene encoding beta-galactosidase (LacZ). Mt4-mmp(-/-) mice had normal gestations, and no apparent defects in growth, life span and fertility. Using LacZ as a marker, we were able to monitor the expression and promoter activity of Mt4-mmp for the first time in vivo. The tissue distribution of Mt4-mmp mRNA correlated with LacZ expression, and we showed that Mt4-mmp is expressed primarily in cerebrum, lung, spleen, intestine and uterus. We identified LacZ-positive neurons in the cerebrum, smooth muscle cells in the intestine and uterus, and macrophages located in the lung alveolar or intraperitoneal space. Contrary to the reported role of MT4-MMP as a tumor necrosis factor-alpha (TNF-alpha) sheddase, the lipopolysaccharide (LPS)-induced release of TNF-alpha from Mt4-mmp(-/-)macrophages was similar to that in wild-type cells, and expression of Mt4-mmp mRNA was repressed following LPS stimulation. Thus, we have established a mutant mouse strain for analyzing the physiological functions of MT4-MMP, which also serves as a sensitive system for monitoring and tracking the expression of MT4-MMP in vivo.
Insights
Researchers developed a novel mouse model to track membrane-type 4 matrix metalloproteinase (MT4-MMP) expression in vivo. This tool helps uncover the biological functions of MT4-MMP across various tissues and cell types.
Area of Science:
- Biochemistry
- Genetics
- Physiology
Background:
- The biological roles of membrane-type 4 matrix metalloproteinase (MT4-MMP/MMP-17) remain largely unknown due to limitations in tracking its in vivo expression.
- A sensitive system is needed to study MT4-MMP's physiological functions.
Purpose of the Study:
- To establish a mutant mouse strain for monitoring MT4-MMP expression and activity in vivo.
- To investigate the tissue distribution and cellular localization of MT4-MMP.
- To explore MT4-MMP's role in TNF-alpha shedding.
Main Methods:
- Generation of a mutant mouse strain (Mt4-mmp(-/-)) replacing Mt4-mmp with a beta-galactosidase (LacZ) reporter gene.
- Analysis of mouse phenotype, including gestation, growth, lifespan, and fertility.
- Monitoring LacZ expression to determine Mt4-mmp expression patterns in vivo.
- Investigating lipopolysaccharide (LPS)-induced TNF-alpha release from macrophages.
Main Results:
- Mt4-mmp(-/-) mice exhibited normal development and fertility.
- LacZ expression accurately reflected Mt4-mmp mRNA distribution, primarily in the cerebrum, lung, spleen, intestine, and uterus.
- Specific cell types expressing MT4-MMP were identified, including neurons, smooth muscle cells, and macrophages.
- LPS-induced TNF-alpha release from Mt4-mmp(-/-) macrophages was comparable to wild-type, and MT4-MMP mRNA expression was repressed by LPS.
Conclusions:
- A functional mutant mouse model for MT4-MMP was successfully created.
- This model enables sensitive in vivo tracking of MT4-MMP expression and facilitates the study of its physiological roles.
- MT4-MMP may not be a primary sheddase for TNF-alpha in macrophages, and its expression is downregulated by LPS stimulation.
