Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neutrophils have been implicated in the pathogenesis of pulmonary injury in many clinical entities, but in vitro studies of neutrophil-mediated pneumocyte damage are limited. To study the role of neutrophils in mediating pulmonary injury, we cocultured these cells with monolayers of human A549 pneumocytes and rat type II alveolar cells. As indexes of injury, we measured cell detachment from monolayers, frank cytolysis, and the effect on pneumocyte protein and DNA synthesis. Unstimulated neutrophils effected minimal lysis or detachment of both pneumocyte targets, but neutrophils stimulated with phorbal myristate acetate and other secretogogues produced marked target cell detachment without lysis, which was time- and dose-dependent. Supernatants of activated neutrophils were similarly effective, suggesting that the mediator was a stable, soluble substance. Catalase and superoxide dismutase were minimally inhibitory to neutrophil-mediated detachment, and neutrophils from patients with chronic granulomatous disease produced detachment comparable to that produced by normal neutrophils. Furthermore, target cells were quite resistant to reagent H2O2 and non-neutrophil-derived toxic oxygen species, further suggesting that oxidative injury was not a major factor in causing detachment. Target cells were susceptible to detachment by the neutral proteases, elastase and collagenase, whereas neutrophil-mediated detachment was markedly inhibited by neutral protease and elastase inhibitors. Human and bovine serum were also inhibitory, but not albumin or pepstatin A, an acid protease inhibitor. Furthermore, we found that activated neutrophils inhibited protein and DNA synthesis of pneumocyte targets, providing additional evidence that neutrophils cause nonlytic injury to pneumocytes. These studies indicate that stimulated neutrophils cause nonlethal injury to pneumocytes, as measured by detachment from monolayers, and inhibition of vital intracellular synthetic functions. The mechanism of detachment is through the action of granule neutral proteases, rather than toxic oxygen metabolites, and is probably due to degradation of the extracellular matrix of the pneumocytes. In vivo, detachment could lead to desquamation of alveolar cells and increased permeability of the epithelial barrier of the lung. Similarly, inhibition of protein and DNA synthesis could have profound effects on the normal function and replication of alveolar epithelium.
 ...
PMID:The injurious effect of neutrophils on pneumocytes in vitro. 673 53

Hepatocytes of 2-acetylaminofluorene-induced hyperplastic nodules of rats treated with clofibrate were transferred to primary culture after dispersion by a collagenase perfusion technique. After 48-hr treatment with dimethylnitrosamine (DMN), the resistance to the agent of the cells forming rod-shaped peroxisomes was examined. Catalase activity of the DMN-resistant cells was also determined. At concentrations of 10(-3)M and 10(-4)M DMN, the resistant cell population of hepatocytes with rod-shaped peroxisomes was larger than that of the cells without abnormal peroxisomes. On the other hand, the catalase activity of the attached cells that remained after DMN treatment decreased as the concentration of DMN was increased. The cells showing a stronger induction of the enzyme activity were found to be more sensitive to the cytotoxicity of DMN and they became detached from the culture dishes.
 ...
PMID:Primary culture of preneoplastic hepatocytes from rats treated with 2-acetylaminofluorene and clofibrate: relationship between resistance to dimethylnitrosamine and responsiveness of peroxisomes. 711 36

The effects of ultraviolet A (UVA) radiation and reactive oxygen species (ROS), generated with a xanthine and xanthine oxidase (XOD) system, on collagen enzymatic degradation involving the matrix metalloproteinase (MMP) and its tissue inhibitor of metalloproteinase (TIMP) were investigated using cultured human dermal fibroblasts. Total RNA was isolated and subjected to Northern blot analysis using cDNA clones for human interstitial collagenase (MMP-1), 72-kDa type IV collagenase (MMP-2) and TIMP-2. UVA irradiation resulted in an increase in MMP-1 mRNA up to 2.3-fold, but did not stimulate MMP-2 or TIMP-2 mRNA expression. In contrast, ROS induced by the xanthine and XOD system resulted in a dose-related increase in the level of MMP-2 mRNA up to 2.1-fold and a decrease in the level of TIMP-2 mRNA by 49% in the same fibroblasts. Catalase, used as scavenger, essentially prevented the ROS-induced alterations in MMP-2 and TIMP-2 mRNA levels. These results suggest that ROS produced in the dermis may contribute to biological changes in the connective tissue matrix observed in photoaging skin by accelerating the MMP-2-related matrix degradation system.
 ...
PMID:The effects of ultraviolet A and reactive oxygen species on the mRNA expression of 72-kDa type IV collagenase and its tissue inhibitor in cultured human dermal fibroblasts. 875 Sep 33