C-Reactive Protein Induces Matrix Metalloproteinase-1 and -10 in Human Endothelial Cells

OBJECTIVES

We examined the effect of C-reactive protein (CRP) on matrix metalloproteinase (MMP) and inhibitor expression in endothelial cells and in patients with clinical and subclinical atherosclerosis.

BACKGROUND

In addition to predicting atherosclerotic vascular disease, CRP may directly promote a proinflammatory/proatherosclerotic phenotype.

METHODS

Human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAECs) were incubated in the presence or absence of CRP (50 mug/ml). Microarray analysis, real-time polymerase chain reaction, immunological and activity assays for MMPs were performed. Specific inhibitors of mitogen-activated protein kinase pathway were used. The MMP-1 and -10 plasma levels were measured in apparently healthy subjects (n = 70). Immunolocalization of CRP, MMP-1, and MMP-10 was performed in human mammary arteries and carotid endarterectomy specimens.

RESULTS

C-reactive protein augmented MMP-1 and -10 messenger ribonucleic acid expression in HUVEC (p < 0.05) and HAEC (p < 0.01). C-reactive protein stimulation also increased MMP-1 and -10 protein in conditioned culture medium (p < 0.001), as well as MMP activity (p = 0.001). Specific inhibition of p38 or MEK abolished the CRP induction of the MMP-1, whereas MMP-10 induction blockade required the simultaneous inhibition of p38 and Jun N-terminal kinase pathways. Subjects with CRP values >3 mg/l (n = 37) had increased plasma MMP-1 and -10 (p < 0.05), the association being significant after adjustment for confounding variables (p = 0.04 and p = 0.008, respectively). The MMP-10 levels were elevated in subjects with higher carotid intima-media thickness (p = 0.009). Increased CRP and MMP-10 colocalized in endothelial layer and macrophage-rich areas in advanced atherosclerotic plaques.

CONCLUSIONS

Increased local and systemic CRP-related MMP activation might provide a link between inflammation and plaque vulnerability.

Serum proteolytic activities and antiproteases in human colorectal carcinoma

Some proteolytic enzymes, trypsin, cathepsin B, cathepsin D, collagenase, elastase and their inhibitors, API and AMG, in serum of patients with colorectal carcinoma have been evaluated. Twenty patients belonged to stage B of colorectal carcinoma, twenty two patients to stage D (Astler and Coller classification) and a control group of thirty healthy volunteers were evaluated. Except in cathepsin D, patients exhibit higher enzymatic activities than healthy subjects, and both groups have all the proteolytic activities assayed in serum. Patients with disseminated disease have increased cathepsin B and collagenase levels, with a decrease of trypsin activity, showing an increment in API and AMG in sera. However, only the API values were significantly higher in patients with metastases. The coexistence of proteolytic activities in human sera together with their inhibitors is considered as well as the origin of these, tumoral and/or reactive, increments. Cathepsin B levels are raised in colorectal neoplasms and contribute to the destruction of the extracellular matrix and the proliferation of tumoral cells. There is evidence that a relation between collagenase like activity and tumor invasiveness exists. Cathepsin B and collagenase increases agree with the tumoral mass. On the other hand, trypsin decrease in metastatic carcinoma is probably related to the increment of their inhibitors, API and AMG, acute phase reactant proteins.

[McArdle's disease. Apropos of a case]

McArdle's disease (glycogenosis type V) is a metabolic disorder of hydrocarbons, inherited with autosomic recessive pattern. Biochemically is defined by a myophosphorylase deficiency; clinically it is characterized by exercise intolerance, due to the impossibility of providing energetic substrate to the muscle, myalgias and stiffness. We present a case report of a patient with McArdle's disease and we comment the diagnostic procedures and current therapeutic options.

Peroxisome enzyme modification and oxidative stress in rat by hypolipidemic and antiinflammatory drugs

Changes in the activities of two peroxisomal enzymes (catalase and thiolase), some parameters related to oxidative situations, such as conjugated dienes, zinc, iron, copper and superoxide dismutase after the administration of two known peroxisome proliferators (clofibrate and acetylsalicylic acid), and two drugs pharmacologically related to the former (probucol and diflunisal) have been studied in male Wistar rats. Administration of the drugs was made by p.o. for 15 days. After the treatment the rats were killed, their livers and brains were taken out, and their blood was collected. Peroxisomes were purified by differential centrifugation followed by ultracentrifugation. Total RNA was also extracted and the acyl CoA oxidase mRNA expression was studied. Clofibrate was inactive on both enzymes studied in liver and diflunisal in brain. However, the acyl CoA oxidase mRNA expression increased by clofibrate treatment. Results are justified by the liposolubility and protein-binding properties of the drugs. Otherwise, the present results show the existence of an increased lipid peroxidation, lower value of superoxide dismutase, and variable results for zinc, copper and iron trace elements. These data evidence an oxidative stress situation in plasma of rats treated with these drugs, probably as a consequence of an increase in some beta-oxidation enzymes, which brings about an overproduction of H2O2.

Insulin-receptor interactions. Possible involvement of metals

Addition of Zn2+ or Cu2+ ions to plasma membrane preparations or to purified insulin receptors from rat liver resulted in an increase of specific insulin binding; no effect was observed with the addition of Fe3+, Ca2+ or Na+. Dialysis of membrane preparations, or of purified receptors, against chelating agents such as zincon (2-carboxy-2'-hydroxy-5'-sulfoformazyl-benzene) or 1,10-phenantroline resulted in a decrease in specific binding of insulin. With the readdition of Zn2+ or Cu2+ to the medium an increase in specific binding was observed, and values much higher than those of the original preparations were obtained; the addition of Ca2+, Fe3+ or Na+ to dialyzed preparations did not cause any effect on the specific binding. Dialysis of purified receptors against chelating agents resulted in a decrease in the content of Zn2+ and Cu2+. Zincon has been found to be a competitive inhibitor of insulin interfering with the specific binding to the receptor, and noncompetitive with the nonspecific binding. These results suggest the possible involvement of a metal ion present in the receptor in the formation of the insulin-receptor complex.