Regulation of matrix metalloproteinases (MMP-2, -3, -9, and -13) by interleukin-1 and interleukin-6 in mouse calvaria: association of MMP induction with bone resorption.
Interleukin-1 (IL-1) greatly induces osteoclast formation and stimulates bone resorption of mouse calvaria in culture. In the presence of soluble IL-6 receptor (sIL-6R), IL-6 similarly induces osteoclast formation, but the potency of IL-6 in inducing bone resorption in organ culture is weaker than that of IL-1. To study the differences in bone-resorbing activity between IL-1 and IL-6, we examined the effects of the two cytokines on the induction of matrix metalloproteinases (MMPs). In mouse calvarial cultures, IL-1 markedly enhanced the messenger RNA (mRNA) expression of MMP-13 (collagenase 3), MMP-2 (gelatinase A), MMP-9 (gelatinase B), and MMP-3 (stromelysin 1), which associated with increases in bone matrix degradation. A hydroxamate inhibitor of MMPs significantly suppressed bone-resorbing activity induced by IL-1. Gelatin zymography showed that both pro- and active-forms of MMP-2 and MMP-9 were detected in the conditioned medium collected from calvarial cultures, and IL-1 markedly stimulated both pro- and active-forms of the two gelatinases. IL-6 with sIL-6R also stimulated mRNA expression and biological activities of these MMPs, but the potency was much weaker than that of IL-1. Conditioned medium collected from IL-1-treated calvariae degraded native type I collagen, but 3/4- and 1/4-length collagen fragments were not detected, suggesting that both collagenases and gelatinases synergistically degraded type I collagen into smaller fragments. In mouse osteoblastic cells, the expression ofMMP-2, MMP-3, and MMP-13 mRNAs could be detected, and they were markedly enhanced by IL-1alpha on days 2 and 5. IL-6 with sIL-6R also induced expression of MMP-13 and MMP-2 mRNAs on day 2, but the expression was rather transient. These results demonstrate that the potency of induction of MMPs by IL-1 and IL-6 is closely linked to the respective bone-resorbing activity, suggesting that MMP-dependent degradation of bone matrix plays a key role in bone resorption induced by these cytokines.
Kusano
K
K
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
Miyaura
C
C
Inada
M
M
Tamura
T
T
Ito
A
A
Nagase
H
H
Kamoi
K
K
Suda
T
T
D000818:Animals; D001862:Bone Resorption / Q000209:etiology*; D003094:Collagen / Q000378:metabolism; D017364:Collagenases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D018093:Gelatinases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis* / Q000235:genetics; D020780:Matrix Metalloproteinase 9; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012886:Skull / Q000201:enzymology*
D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D003094:Collagen; D017364:Collagenases; D018093:Gelatinases; D008666:Metalloendopeptidases; D019278:Matrix Metalloproteinase 3; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9