Matrix Metalloproteins Research Articles

Recent Advances in the Development of MMPIs and APNIs Based on the Pyrrolidine Platforms

Pyrrolidine scaffold has been widely used to design a variety of N-heterocyclic derivatives towards various targets. Amongst them, matrix metalloproteins (MMPs) and aminopeptidase N (APN) represent two kinds of important metalloproteinase targets which have been proved to be tightly related to tumor proliferation, invasion, metastasis and angiogenesis. As a result, their respective inhibitors, namely MMP inhibitors (MMPIs) and APN inhibitors (APNIs), have been systematically studied in our group for many years. Recent advances in the elucidation of MMPIs and APNIs based on the pyrrolidine platforms are briefly reviewed in this paper.

The role of interleukin 18 in the pathogenesis of hypertension-induced vascular disease

Understanding the mechanism by which chronic high blood pressure induces vascular disease is of fundamental importance for prevention of the adverse consequences of hypertension. Clinical and population studies have consistently found increased circulating levels of interleukin 18 (IL-18) in patients with hypertension. Although obesity, and possibly age, is a determinant of plasma IL-18 levels, the relationship of IL-18 to hypertension seems to be independent of these factors. Experimental evidence indicates that the expression of IL-18 and/or its receptor can be induced by catecholamines or angiotensin, two factors that are involved in the pathophysiology of hypertension. Elevated circulating IL-18 levels are associated with vascular changes in the carotid artery, including increased carotid intima-media thickness, which, in turn, is a predictor of cardiovascular events in patients with established coronary disease. IL-18, either directly or through oxidative stress pathways and matrix metalloproteins, can alter endothelial function or induce vascular smooth muscle cell migration and/or proliferation to produce the vascular changes that occur with hypertension. This Review examines the data on IL-18 and hypertensive vascular disease, and explores the potential cellular and molecular mechanisms that might connect hypertension to vascular disease.

Fate of the hypertrophic chondrocyte: Microenvironmental perspectives on apoptosis and survival in the epiphyseal growth plate

The goal of this review is to examine the fate of the hypertrophic chondrocyte in the epiphyseal growth plate and consider the impact of the cartilage microenvironment on cell survival and apoptosis. Early investigations pointed to a direct role of the hypertrophic chondrocyte in osteogenesis. The terminally differentiated cells were considered to undergo a dramatic change in shape, size, and phenotype, and assume the characteristics of an osteoblast. While some studies have supported the notion of transdifferentiation, much of the evidence in favor of reprogramming epiphyseal chondrocytes is circumstantial and based on microscopic evaluation of cells that are present at the chondro-osseous junction. Although these investigations provided a novel perspective on endochondral bone formation, they were flawed by the failure to consider the importance of stem cells in osseous tissue formation. Subsequent studies indicated that many, if not all, of the cells of the cartilage plate die through the induction of apoptosis. With respect to agents that mediate apoptosis, at the chondro-osseous junction, solubilization of mineral and hydrolysis of organic matrix constituents by septoclasts generates high local concentrations of ions, peptides, and glycans, and secreted matrix metalloproteins. Individually, and in combination, a number of these agents serve as potent chondrocyte apoptogens. We present a new concept: hypertrophic cells die through the induction of autophagy. In the cartilage microenvironment, combinations of local factors cause chondrocytes to express an initial survival phenotype and oxidize their own structural macromolecules to generate ATP. While delaying death, autophagy leads to a state in which cells are further sensitized to changes in the local microenvironment. One such change is similar to ischemia reperfusion injury, a condition that leads to tissue damage and cell death. In the growth cartilage, an immediate effect of this type of injury is sensitization to local apoptogens. These two concepts (type II programmed cell death and ischemia reperfusion injury) emphasize the importance of the local microenvironment, in particular pO(2), in directing chondrocyte survival and apoptosis.

Spectrum of Calcific Aortic Valve Disease

Received October 26, 2004; revision received January 13, 2005; accepted February 4, 2005. Calcific aortic valve disease is a slowly progressive disorder with a disease continuum that ranges from mild valve thickening without obstruction of blood flow, termed aortic sclerosis, to severe calcification with impaired leaflet motion, or aortic stenosis (Figure 1). In the past, this process was thought to be “degenerative” because of time-dependent wear-and-tear of the leaflets with passive calcium deposition. Now, there is compelling histopathologic and clinical data suggesting that calcific valve disease is an active disease process akin to atherosclerosis with lipoprotein deposition, chronic inflammation, and active leaflet calcification. The overlap in the clinical factors associated with calcific valve disease and atherosclerosis and the correlation between the severity of coronary artery and aortic valve calcification provide further support for a shared disease process. Figure 1. Gross specimen of minimally diseased aortic valve (left) and severely stenotic aortic valve (right). In the severely stenotic valve, there are prominent lipocalcific changes on aortic side of valve cusps (arrow), with sparing of commissures. ### Anatomy of Normal Aortic Valve The normal aortic valve comprises 3 layers. The ventricularis, on the ventricular side of the leaflet, is composed of elastin-rich fibers that are aligned in a radial direction, perpendicular to the leaflet margin. The fibrosa, on the aortic side of the leaflet, comprises primarily fibroblasts and collagen fibers arranged circumferentially, parallel to the leaflet margin. The spongiosa is a layer of loose connective tissue at the base of the leaflet, between the fibrosa and ventricularis, composed of fibroblasts, mesenchymal cells, and a mucopolysaccharide-rich matrix. These layers work in concert to provide tensile strength and pliability for decades of repetitive motion. ### Early Lesion of Aortic Sclerosis Histopathologic studies of aortic sclerosis show focal subendothelial plaquelike lesions on the aortic side of the leaflet that extend to the adjacent fibrosa layer. Similarities to …

Enzymes implicated in arthritis, cancer clarified

An enzyme thought to perpetrate the onset of arthritis has been purified and cloned [ Science , 284 , 1664 (1999)]. And the crystal structure of an enzyme believed to enable cancer cells to spread has been determined [ Science , 284,1667 (1999)]. The feats, achieved by separate research groups, offer new leads for drugs to treat arthritis and cancer. Both enzymes are metalloproteinases. Human matrix metalloproteinase-2 (MMP-2) and other MMPs degrade the extracellular matrix, clearing the way for cancer cells to migrate. Aggrecanase-1 (cloned by a 26-member team at DuPont Pharmaceuticals, Wilmington, Del., in collaboration researchers at the University of Kansas Medical School, Kansas City) hydrolyzes aggrecan, a proteoglycan that endows cartilage with its properties of compressibility and resilience, explains lead author Micky D. Tortorella. Other enzymes that degrade extracellular matrix are known to clip aggrecan at a specific site. However, the aggrecan fragments these matrix metalloproteins gen...