Overexpression of tissue inhibitor of metalloproteinase 3 in macrophages reduces atherosclerosis in low-density lipoprotein receptor knockout mice.
OBJECTIVE
Tissue inhibitor of metalloproteinase 3 (TIMP3) is a stromal protein that inhibits the activity of proteases and receptors. TIMP3 is downregulated in metabolic and inflammatory disorders, such as type 2 diabetes mellitus and atherosclerosis, particularly in regions enriched with monocyte/macrophage cells. To investigate the role of TIMP3 in atherosclerosis, we generated a new mouse model in which Timp3 was overexpressed in the atherosclerotic plaque via a macrophage-specific promoter (MacT3). We elucidated any potential antiatherosclerotic effects of TIMP3, including regulation of monocyte/macrophage recruitment within atherosclerotic plaques, in MacT3 mice crossbred with low-density lipoprotein receptor knockout (LDLR(-/-)) mice.


RESULTS
MacT3/LDLR(-/-) mice had an improvement of atherosclerosis and metabolic parameters compared with LDLR(-/-). En face aorta and aortic root examination of MacT3/LDLR(-/-) mice revealed smaller atherosclerotic plaques with features of stability, such as increased collagen content and decreased necrotic core formation. Atherosclerotic plaques in MacT3/LDLR(-/-) mice contained fewer T cells and macrophages. Furthermore, TIMP3 overexpression in macrophages resulted in reduced oxidative stress signals, as evidenced by lower lipid peroxidation, protein carbonylation, and nitration in atheromas.


CONCLUSIONS
Our study confirmed that macrophage-specific overexpression of TIMP3 decreases the inflammatory content and the amplitude of atherosclerotic plaques in mice.
Department of Internal Medicine, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
Viviana
V
Casagrande
Rossella
R
Menghini
Stefano
S
Menini
Arianna
A
Marino
Valentina
V
Marchetti
Michele
M
Cavalera
Marta
M
Fabrizi
Marta L
ML
Hribal
Giuseppe
G
Pugliese
Paolo
P
Gentileschi
Orazio
O
Schillaci
Ottavia
O
Porzio
Davide
D
Lauro
Paolo
P
Sbraccia
Renato
R
Lauro
Massimo
M
Federici
D000818:Animals; D050197:Atherosclerosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004036:Diet, Atherogenic / Q000009:adverse effects; D004195:Disease Models, Animal; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D011973:Receptors, LDL / Q000172:deficiency* / Q000235:genetics; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D011973:Receptors, LDL; D019717:Tissue Inhibitor of Metalloproteinase-3