Vascular endothelial growth factor (VEGF) is a strong angiogenic mitogen and plays important roles in angiogenesis under various pathophysiological conditions. The in vivo angiogenic activity of secreted VEGF may be regulated by extracellular inhibitors, because it is also produced in avascular tissues such as the cartilage. To seek the binding inhibitors against VEGF, we screened the chondrocyte cDNA library by a yeast two‐hybrid system by using VEGF ₁₆₅ as bait and identified connective tissue growth factor (CTGF) as a candidate. The complex formation of VEGF ₁₆₅ with CTGF was first established by immunoprecipitation from the cells overexpressing both binding partners. A competitive affinity‐binding assay also demonstrated that CTGF binds specifically to VEGF ₁₆₅ with two classes of binding sites (Kd = 26 ± 11 nM and 125 ± 38 nM). Binding assay using deletion mutants of CTGF indicated that the thrombospondin type‐1 repeat (TSP‐1) domain of CTGF binds to the exon 7‐coded region of VEGF ₁₆₅ and that the COOH‐terminal domain preserves the affinity to both VEGF ₁₆₅ and VEGF ₁₂₁ . The interaction of VEGF ₁₆₅ with CTGF inhibited the binding of VEGF ₁₆₅ to the endothelial cells and the immobilized KDR/IgG Fc; that is, a recombinant protein for VEGF ₁₆₅ receptor. By in vitro tube formation assay of endothelial cells, full‐length CTGF and the deletion mutant possessing the TSP‐1 domain inhibited VEGF ₁₆₅ ‐induced angiogenesis significantly in the complex form. This antiangiogenic activity of CTGF was demonstrated further by in vivo angiogenesis assay by using Matrigel injection model in mice. These data demonstrate for the first time that VEGF ₁₆₅ binds to CTGF through a protein‐to‐protein interaction and suggest that the angiogenic activity of VEGF ₁₆₅ is regulated negatively by CTGF in the extracellular environment.

Mycobacterium tuberculosis can cause lung tissue damage to spread, but the mechanisms driving this immunopathology are poorly understood. The breakdown of lung matrix involves MMPs, which have a unique ability to degrade fibrillar collagens at neutral pH. To determine whether MMPs play a role in the immunopathology of tuberculosis (TB), we profiled MMPs and their inhibitors, the tissue inhibitor of metalloproteinases (TIMPs), in sputum and bronchoalveolar lavage fluid from patients with TB and symptomatic controls. MMP-1 concentrations were significantly increased in both HIV-negative and HIV-positive patients with TB, while TIMP concentrations were lower in HIV-negative TB patients. In primary human monocytes, M. tuberculosis infection selectively upregulated MMP1 gene expression and secretion, and Ro32-3555, a specific MMP inhibitor, suppressed M. tuberculosis–driven MMP-1 activity. Since the mouse MMP-1 ortholog is not expressed in the lung and mice infected with M. tuberculosis do not develop tissue destruction equivalent to humans, we infected transgenic mice expressing human MMP-1 with M. tuberculosis to investigate whether MMP-1 caused lung immunopathology. In the MMP-1 transgenic mice, M. tuberculosis infection increased MMP-1 expression, resulting in alveolar destruction in lung granulomas and significantly greater collagen breakdown. In summary, MMP-1 may drive tissue destruction in TB and represents a therapeutic target to limit immunopathology.

Cellular functions within tissues are strictly regulated by the tissue microenvironment which comprises extracellular matrix and extracellular matrix‐deposited factors such as growth factors, cytokines and chemokines. These molecules are metabolized by matrix metalloproteinases (MMP), a disintegrin and metalloproteinases (ADAM) and ADAM with thrombospondin motifs (ADAMTS), which are members of the metzincin superfamily. They function in various pathological conditions of both neoplastic and non‐neoplastic diseases by digesting different substrates under the control of tissue inhibitors of metalloproteinases (TIMP) and reversion‐inducing, cysteine‐rich protein with Kazal motifs (RECK). In neoplastic diseases MMP play a central role in cancer cell invasion and metastases, and ADAM are also important to cancer cell proliferation and progression through the metabolism of growth factors and their receptors. Numerous papers have described the involvement of these metalloproteinases in non‐neoplastic diseases in nearly every organ. In contrast to the numerous review articles on their roles in cancer cell proliferation and progression, there are very few articles discussing non‐neoplastic diseases. This review therefore will focus on the properties of MMP, ADAM and ADAMTS and their implications for non‐neoplastic diseases of the cardiovascular system, respiratory system, central nervous system, digestive system, renal system, wound healing and infection, and joints and muscular system.