TIMP3 is reduced in atherosclerotic plaques from subjects with type 2 diabetes and increased by SirT1.
OBJECTIVE
Atherosclerosis is accelerated in subjects with type 2 diabetes by unknown mechanisms. We identified tissue inhibitor of metalloproteinase 3 (TIMP3), the endogenous inhibitor of A disintegrin and metalloprotease domain 17 (ADAM17) and other matrix metalloproteinases (MMPs), as a gene modifier for insulin resistance and vascular inflammation in mice. We tested its association with atherosclerosis in subjects with type 2 diabetes and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression.


METHODS
We investigated ADAM10, ADAM17, MMP9, TIMP1, TIMP2, TIMP3, and TIMP4 expression levels in human carotid atherosclerotic plaques (n = 60) from subjects with and without diabetes. Human vascular smooth muscle cells exposed to several metabolic stimuli were used to identify regulators of TIMP3 expression. SirT1 small interference RNA, cDNA, and TIMP3 promoter gene reporter were used to study SirT1-dependent regulation of TIMP3.


RESULTS
Here, we show that in human carotid atherosclerotic plaques, TIMP3 was significantly reduced in subjects with type 2 diabetes, leading to ADAM17 and MMP9 overactivity. Reduced expression of TIMP3 was associated in vivo with SirT1 levels. In smooth muscle cells, inhibition of SirT1 activity and levels reduced TIMP3 expression, whereas SirT1 overexpression increased TIMP3 promoter activity.


CONCLUSIONS
In atherosclerotic plaques from subjects with type 2 diabetes, the deregulation of ADAM17 and MMP9 activities is related to inadequate expression of TIMP3 via SirT1. Studies in vascular cells confirmed the role of SirT1 in tuning TIMP3 expression.
Cardellini
Marina
M
Department of Internal Medicine, University of Rome Tor Vergata, Rome, Italy.
Menghini
Rossella
R
Martelli
Eugenio
E
Casagrande
Viviana
V
Marino
Arianna
A
Rizza
Stefano
S
Porzio
Ottavia
O
Mauriello
Alessandro
A
Solini
Anna
A
Ippoliti
Arnaldo
A
Lauro
Renato
R
Folli
Franco
F
Federici
Massimo
M
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072198:ADAM17 Protein; D000818:Animals; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D002339:Carotid Arteries / Q000378:metabolism; D002340:Carotid Artery Diseases / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D056564:Sirtuin 1; D037761:Sirtuins / Q000378:metabolism*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000378:metabolism*
C088390:TIMP3 protein, human; D019717:Tissue Inhibitor of Metalloproteinase-3; D051722:ADAM Proteins; D020780:Matrix Metalloproteinase 9; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606463:Adam17 protein, mouse; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins