Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysyl oxidase activity was measured in lung extracts of hamsters with elastase-induced emphysema 8 days after administration of the enzyme and again after 2, 3, and 4 wk. Levels of activity rose rapidly to 7 times the base values determined in the lungs of saline-injected control animals. In parallel with the increase in lysyl oxidase activity, the rate of 14C-lysine incorporation into desmosine and isodesmosine was at its maximum 1 wk after elastase administration, reflecting the lysyl-oxidase-mediated cross-link formation, which is the final step in the resynthesis of the pulmonary elastin destroyed by the elastolytic insult.
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PMID:Stimulation of lung lysyl oxidase activity in hamsters with elastase-induced emphysema. 285 74

The nonelastolytic proteases trypsin and chymotrypsin were administered to hamsters 24 hours after intratracheal injection of elastase. Severity of the disease, extent of degradation and resynthesis, new cross-link formation, and the levels of the enzyme lysyl oxidase, which mediates the cross-link formation, were compared with the same parameters measured in hamsters with experimental emphysema induced by elastase alone. Increases in mean linear intercept indicated that a more severe form of the disease was produced. Although elastin degradation after 1 week was similar in both groups, resynthesis of the elastin destroyed by the elastolytic insult was significantly impaired in the animals injected sequentially with elastase and trypsin or chymotrypsin. Formation of new elastin as monitored by 14C-lysine incorporation into the elastin specific cross-links desmosine and isodesmosine was reduced approximately 40%, although there was no significant difference in the levels of lysyl oxidase activity. It is suggested that the most likely mechanism compatible with the recorded observations involves destruction of the microfibrillar component of the elastic fiber by trypsin or chymotrypsin, resulting in the absence of the requisite template for resynthesis of the pulmonary elastin.
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PMID:Impairment of elastin resynthesis in the lungs of hamsters with experimental emphysema induced by sequential administration of elastase and trypsin. 285 57

The severity of pulmonary emphysema can be affected by exposure to cigarette smoke in several ways. Inactivation of alpha-1-antitrypsin and recruitment of leukocytes to lung airways shifts the protease-antiprotease balance towards increased elastolytic activity. The present study demonstrates an additional effect of cigarette smoke inhalation and retardation of the repair process and of the neosynthesis of cross-linked elastin. Hamsters with elastase-induced emphysema, exposed to cigarette smoke for 1 wk immediately after elastase administration, showed a 40% reduction of 14C-lysine incorporation into the elastin-specific cross-links, desmosine, and isodesmosine. Concomitantly, there was a decrease in the level of lung lysyl oxidase to that observed in uninjured control animals, in sharp contrast to the sevenfold increase in lysyl oxidase activity in hamsters with elastase-induced emphysema recovering under atmospheric conditions. These findings suggest that impairment of the production of lysyl oxidase and the resynthesis of cross-linked elastin by smoke inhalation exacerbates alveolar destruction.
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PMID:Cigarette smoke impairs elastin resynthesis in lungs of hamsters with elastase-induced emphysema. 392 58

A mild form of emphysema was produced in pigs raised on a copper-deficient, zinc-supplemented diet. The copper-requiring enzyme, lysyl oxidase, catalyzes the cross-linking of tropoelastin into mature elastin. Zinc further inhibits the activity of lysyl oxidase. Lungs from animals raised on copper-deficient, zinc-supplemented diets of demonstrate perforations in alveolar walls and diminished amounts of elastin bronchi and pulmonary arteries. Mean linear intercepts are greater and alveolar internal surface areas are less than those in control animals, fulfilling the generally accepted definition of emphysema. Physiologic confirmation is provided by a leftward shift of the saline volume-pressure curves when compared with those in control animals. Ultrastructurally, the alveolar walls are effaced and pores of Kohn are enlarged. There are areas in which elastin is absent leaving remnant microfibrils, and there are other changes consistent with active elastin synthesis. Biochemical data demonstrate no difference in elastin content as micrograms/ml of fat-free dry weight but do demonstrate increased collagen content in experimental animal lungs compared with that in control lungs. Ultrastructural similarities to enzyme-induced models of emphysema suggest the presence of elastin degradation in our model. We speculate that although the copper-deficient, zinc-supplemented state may stimulate protein synthesis in general, elastin is being degraded by endogenous means, but collagen is not.
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PMID:A copper-deficient, zinc-supplemented diet produces emphysema in pigs. 612 18

Water-soluble components of the gas phase of filtered cigarette smoke inhibit formation of covalent desmosine cross-links during conversion of tropoelastin to elastin in vitro. These same smoke components also suppress lysyl-oxidase-catalyzed oxidation of lysine epsilon-amino groups in tropoelastin (the chemical step preceding formation of all elastin cross-links, including desmosine) in a dose-dependent fashion. However, gas phase smoke does not block the oxidation of diaminopentane by lysyl oxidase. Thus, gas phase cigarette smoke may possess substrate-directed (rather than enzyme-directed) inhibitory components capable of interfering with elastin cross-linking in vitro. Similar effects occurring in smokers' lungs could impede elastin repair and contribute to the development of pulmonary emphysema.
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PMID:Cigarette smoke blocks cross-linking of elastin in vitro. 683 36

Elastic fibers are components of the extracellular matrix and confer resilience. Once laid down, they are thought to remain stable, except in the uterine tract where cycles of active remodeling occur. Loss of elastic fibers underlies connective tissue aging and important diseases including emphysema. Failure to maintain elastic fibers is explained by a theory of antielastase-elastase imbalance, but little is known about the role of renewal. Here we show that mice lacking the protein lysyl oxidase-like 1 (LOXL1) do not deposit normal elastic fibers in the uterine tract post partum and develop pelvic organ prolapse, enlarged airspaces of the lung, loose skin and vascular abnormalities with concomitant tropoelastin accumulation. Distinct from the prototypic lysyl oxidase (LOX), LOXL1 localizes specifically to sites of elastogenesis and interacts with fibulin-5. Thus elastin polymer deposition is a crucial aspect of elastic fiber maintenance and is dependent on LOXL1, which serves both as a cross-linking enzyme and an element of the scaffold to ensure spatially defined deposition of elastin.
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PMID:Elastic fiber homeostasis requires lysyl oxidase-like 1 protein. 1474 49

Lysyl oxidase (LO), a copper-dependent enzyme, plays a critical role in the formation and repair of the extracellular matrix (ECM) by catalyzing the crosslinking of elastin and collagen. To better understand mechanisms of cigarette smoke (CS)-induced emphysema, we examined changes in LO and its substrates, i.e., elastin and collagen type I, the major components of cellular thiols, i.e., metallothionein (MT) and glutathione (GSH), and gamma-glutamylcysteine synthetase (gamma-GCS), a key enzyme for GSH biosynthesis, in cigarette smoke condensate (CSC)-treated rat fetal lung fibroblasts (RFL6). Exposure of RFL6 cells to CSC decreased levels of LO catalytic activity, mRNA, and protein, i.e., the 46 kDa preproenzyme, the 50 kDa proenzyme and the 32 kDa mature enzyme in a dose-dependent manner. In addition, CSC also inhibited the expression of collagen type I and elastin, substrates of LO and important components of the lung ECM. Meanwhile, cellular thiols including MT and GSH as well as gamma-GCS were markedly upregulated in CSC-treated cells. To evaluate modulation of LO expression by cellular thiols, we further examined the effect of increased levels of GSH on LO expression at protein and catalytic levels. Interestingly, exposure of cells to glutathione monoethyl ester, a GSH delivery system, effectively elevated cellular GSH levels and induced a dose-dependent decrease in levels of the protein species and catalytic activity of LO. These results suggest that upregulation by CSC of cellular thiols may play an important role in the downregulation of LO and subsequently destabilization of the lung ECM in CS-induced emphysema.
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PMID:Downregulation of lysyl oxidase and upregulation of cellular thiols in rat fetal lung fibroblasts treated with cigarette smoke condensate. 1550 64

Lysyl oxidase (LO) catalyzes crosslinking of collagen and elastin essential for maintaining the structural integrity of the lung extracellular matrix (ECM). To understand mechanisms of cigarette smoke (CS)-induced emphysema, we investigated effects of cigarette smoke condensate (CSC), the particulate matter of CS, on LO mRNA expression in cultured rat fetal lung fibroblasts (RFL6). Exposure of RFL6 cells to 0-120 microg CSC/ml for 24 h induced a dose-dependent inhibition of LO steady-state mRNAs, for example, reducing transcript levels to below 10% of the control in cells incubated with 80-120 microg CSC/ml. Nuclear run-on assays indicated a marked reduction in LO relative transcriptional rates amounting to 27.7% of the control in cells treated with 120 microg CSC/ml. The actinomycin D-chase assay showed that CSC enhanced the instability of LO transcripts. The t1/2 for LO mRNA decay was decreased from 24 h in the control to 4.5 h in cells treated with 120 microg CSC/ml. Moreover, 80-120 microg CSC/ml also inhibited LO promoter activity as revealed by suppression of reporter gene expression in cells transfected with LO promoter-luciferase vectors. Thus, inhibition of LO transcription initiation and enhancement of LO mRNA instability both contributed to downregulation of LO steady-state mRNA in CSC-treated cells. Note that inhibition of LO mRNA expression by CSC was closely accompanied by markedly decreased levels of transcripts of collagen type I and tropoelastin, two substrates of LO. Thus, transcriptional perturbation of LO and its substrates may be a critical mechanism for ECM damage in CS-induced emphysema.
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PMID:Transcriptional and posttranscriptional inhibition of lysyl oxidase expression by cigarette smoke condensate in cultured rat fetal lung fibroblasts. 1593 28

Menkes disease is an X-linked recessive disorder of copper transport characterized by neurological deterioration, connective tissue, and vascular defects, abnormal hair, and death in early childhood. We report on a patient with Menkes disease in whom severe diffuse emphysema caused respiratory failure and death at 14 months of age. He had severe growth and developmental delays and other typical clinical manifestations of Menkes disease. He developed respiratory problems requiring continuous supplemental oxygen and a progressively enlarging soft tissue mass appeared on the neck. Imaging studies revealed cystic spaces in multiple lobes of the lung consistent with bullous emphysema. The neck mass was determined to be an internal jugular venous aneurysm. At autopsy, extensive emphysematous change was evident. Post-mortem barium injections of the pulmonary arterial system revealed marked dilatation and tortuosity of the preacinar pulmonary arteries and reduced numbers of intra-acinar arteries. Severe emphysema, presumably caused by abnormal elastin due to deficiency of the copper-dependent enzyme lysyl oxidase, may represent an underestimated clinical complication of Menkes disease and should be considered in the differential diagnosis of chronic respiratory disease in these patients.
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PMID:Severe bilateral panlobular emphysema and pulmonary arterial hypoplasia: unusual manifestations of Menkes disease. 1627 98

Copper (Cu)-dependent lysyl oxidase (LO) catalyzes crosslinking of collagen and elastin stabilizing the extracellular matrix (ECM). Chronic inhalation of cadmium (Cd), a toxic metal, induces emphysema. To probe mechanisms of Cd injury to the lung, we developed Cd-resistant (CdR) cells from rat fetal lung fibroblasts (RFL6) by chronic exposure to CdCl(2) from 1 to 40 microM and further examined their expressions of LO, LO substrates, and Cu-scavenging thiols. Levels of cellular thiols, metallothionein, and glutathione in CdR cells were elevated to 13.0- and 3.2-fold of parental controls, respectively, whereas LO mRNA and protein levels were markedly reduced in these cells, with catalytic activity declining to only 16% of the parental control. A conspicuous 52 kDa species rather then the normal 50 kDa proenzyme appeared in the CdR cell extract but not in the conditioned medium, which was codistributed with the endoplasmic reticulum marker [DiOC5(3)] within the cell, implying the Cd-induced 52 kDa species as a product of an abnormal LO-processing defect in secretion. Addition of Cu into CdR cell cultures enhanced the expression of LO mRNA, protein and catalytic activities reflecting limitation of Cu bioavailability for LO in these cells. With inhibition of LO, CdR cells also displayed downregulation of collagen and elastin, substrates of LO. Restoration of collagen synthesis by exposure of CdR cells to purified LO or Cu suggests that inhibition of LO and limitation of Cu cofactor by Cd, as key phenotype changes, accelerated collagen and elastin damage, a critical event pertinent to emphysema pathogenesis.
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PMID:Inhibition of the expression of lysyl oxidase and its substrates in cadmium-resistant rat fetal lung fibroblasts. 1643 78


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