Sorsa T, Ramamurthy N S, Vernillo A T, Zhang X, Konttinen Y T, Rifkin B R, Golub L M
Department of Medical Chemistry, Institute of Dentistry, University of Helsinki and Helsinki University Central Hospital, Finland.
J Rheumatol. 1998 May;25(5):975-82.
We studied the relative ability of 6 different chemically modified non-antimicrobial analogs of tetracycline (CMT) to inhibit human and chicken matrix metalloproteinases (MMP) in vitro. The ability of tetracycline and its analogs to inhibit MMP appears to depend on the Ca++/Zn++ binding site at C11 (carbonyl oxygen) and C12 (OH group) of the molecule, which is lacking in CMT-5, the pyrazole derivative of tetracycline. This significant property of CMT-5 was used to differentiate between the effects of CMT on already active MMP versus the oxidative activation of latent MMP (pro-MMP).
Cultured chicken osteoclast conditioned medium and purified human neutrophil progelatinase (MMP-9) and pro-collagenase (MMP-8) were assayed for proteinase activities using gelatin and collagen, respectively. The pro-MMP were activated either by preincubation with 1 mM aminophenylmercuric acetate (APMA) or 100 microM sodium hypochlorite (NaOCI). CMT were added either to the preincubation mixtures together with NaOCl or after activation of pro-MMP with NaOCl.
All CMT tested, except CMT-5, inhibited APMA or NaOCl activated pro-MMP. However, CMT-5 (like the other CMT), inhibited the oxidative activation of pro-MMP by NaOCl when added together by scavenging the reactive oxygen species. The degradation of type-I collagen by chicken osteoclast conditioned medium was probably due to MMP-2 and/or MMP-13.
Oxidative activation of pro-MMP may be crucial during soft tissue/bone destruction in the inflammatory diseases, including the arthritides. Our results indicate that the Ca++/Zn++ binding site of CMT is not essential for inhibition of the oxidative activation of pro-MMP.
我们研究了6种不同的四环素化学修饰非抗菌类似物（CMT）在体外抑制人及鸡基质金属蛋白酶（MMP）的相对能力。四环素及其类似物抑制MMP的能力似乎取决于分子中C11（羰基氧）和C12（羟基）处的Ca++/Zn++结合位点，而四环素的吡唑衍生物CMT-5缺乏该位点。利用CMT-5的这一显著特性来区分CMT对已激活的MMP的作用与对潜伏MMP（前MMP）的氧化激活作用。
分别使用明胶和胶原蛋白检测培养的鸡破骨细胞条件培养基以及纯化的人中性粒细胞前明胶酶（MMP-9）和前胶原酶（MMP-8）的蛋白酶活性。前MMP通过与1 mM乙酸氨基苯汞（APMA）或100 microM次氯酸钠（NaOCl）预孵育来激活。CMT要么与NaOCl一起添加到预孵育混合物中，要么在NaOCl激活前MMP后添加。
除CMT-5外，所有测试的CMT均抑制APMA或NaOCl激活的前MMP。然而，CMT-5（与其他CMT一样）在与NaOCl一起添加时，通过清除活性氧来抑制NaOCl对前MMP的氧化激活。鸡破骨细胞条件培养基对I型胶原蛋白的降解可能归因于MMP-2和/或MMP-13。
在前MMP的氧化激活在包括关节炎在内的炎症性疾病的软组织/骨破坏过程中可能至关重要。我们的结果表明，CMT的Ca++/Zn++结合位点对于抑制前MMP的氧化激活并非必不可少。
