Aminoalkylaziridines as substrates and inhibitors of lysyl oxidase specific inactivation of the enzyme by n- 5-aminopentyl aziridine

Kagan, Herbert M.

doi:10.2741/a247

Cited by 12 publications

(4 citation statements)

References 19 publications

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“…After compensating for the added fumarate salt, this concentration corresponds to 0.0137mM BAPN, as compared with the 0.137mM BAPN concentration used in the current study. Given that this tenfold higher 0.137mM BAPN concentration corresponded to five times the half-maximal inhibitory BAPN concentration in vivo [49,50], we expected greater lysyl oxidase inhibition to be induced in vitro . In other words, the quantitative analysis of collagen synthesized in vitro reflects a direct rather than systemic effect of lysyl oxidase inhibition by BAPN.…”

Section: Discussionmentioning

confidence: 99%

β-Aminopropionitrile-Induced Reduction in Enzymatic Crosslinking Causes In Vitro Changes in Collagen Morphology and Molecular Composition

Canelón

Wallace

2016

PLoS ONE

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Type I collagen morphology can be characterized using fibril D-spacing, a metric which describes the periodicity of repeating bands of gap and overlap regions of collagen molecules arranged into collagen fibrils. This fibrillar structure is stabilized by enzymatic crosslinks initiated by lysyl oxidase (LOX), a step which can be disrupted using β-aminopropionitrile (BAPN). Murine in vivo studies have confirmed effects of BAPN on collagen nanostructure and the objective of this study was to evaluate the mechanism of these effects in vitro by measuring D-spacing, evaluating the ratio of mature to immature crosslinks, and quantifying gene expression of type I collagen and LOX. Osteoblasts were cultured in complete media, and differentiated using ascorbic acid, in the presence or absence of 0.25mM BAPN-fumarate. The matrix produced was imaged using atomic force microscopy (AFM) and 2D Fast Fourier transforms were performed to extract D-spacing from individual fibrils. The experiment was repeated for quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Fourier Transform infrared spectroscopy (FTIR) analyses. The D-spacing distribution of collagen produced in the presence of BAPN was shifted toward higher D-spacing values, indicating BAPN affects the morphology of collagen produced in vitro, supporting aforementioned in vivo experiments. In contrast, no difference in gene expression was found for any target gene, suggesting LOX inhibition does not upregulate the LOX gene to compensate for the reduction in aldehyde formation, or regulate expression of genes encoding type I collagen. Finally, the mature to immature crosslink ratio decreased with BAPN treatment and was linked to a reduction in peak percent area of mature crosslink hydroxylysylpyridinoline (HP). In conclusion, in vitro treatment of osteoblasts with low levels of BAPN did not induce changes in genes encoding LOX or type I collagen, but led to an increase in collagen D-spacing as well as a decrease in mature crosslinks.

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Section: Discussionmentioning

confidence: 99%

β-Aminopropionitrile-Induced Reduction in Enzymatic Crosslinking Causes In Vitro Changes in Collagen Morphology and Molecular Composition

Canelón

Wallace

2016

PLoS ONE

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“…While the bulk quantification of crosslinks using high performance liquid chromatography would be inconclusive in the current study due to the modest effect of BAPN and the relative amount of pre-existing tissue to tissue formed during BAPN treatment, quantifying crosslinks in a model where a higher dose was used over a longer period is needed to conclude whether or not the modest effect in this model is due to a failure to adequately inhibit crosslinks or simply enzymatic crosslinks are not as important in determining macroscale mechanical properties as believed. Additionally, the timing of the injections in future studies should be optimized to coincide with the circadian rhythm of bone formation so that over the approximately 2.5 hours when the serum concentration of BAPN is above the half maximal inhibitory concentration of 25 μM bone formation is at its peak [ 42 – 45 ]. Alternatively, other administration routes that do not rely on timing a bolus of BAPN may be more successful in generating an overt mechanical disease state such as osmotic pumps [ 46 ] or dietary supplements [ 47 , 48 ] that deliver near constant or repeated doses over the course of the day to maintain efficacy despite rapid clearance.…”

Section: Discussionmentioning

confidence: 99%

Treadmill Exercise Improves Fracture Toughness and Indentation Modulus without Altering the Nanoscale Morphology of Collagen in Mice

et al. 2016

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The specifics of how the nanoscale properties of collagen (e.g., the crosslinking profile) affect the mechanical integrity of bone at larger length scales is poorly understood despite growing evidence that collagen’s nanoscale properties are altered with disease. Additionally, mass independent increases in postyield displacement due to exercise suggest loading-induced improvements in bone quality associated with collagen. To test whether disease-induced reductions in bone quality driven by alterations in collagen can be rescued or prevented via exercise-mediated changes to collagen’s nanoscale morphology and mechanical properties, the effects of treadmill exercise and β-aminopropionitrile treatment were investigated. Eight week old female C57BL/6 mice were given a daily subcutaneous injection of either 164 mg/kg β-aminopropionitrile or phosphate buffered saline while experiencing either normal cage activity or 30 min of treadmill exercise for 21 consecutive days. Despite differences in D-spacing distribution (P = 0.003) and increased cortical area (tibial: P = 0.005 and femoral: P = 0.015) due to β-aminopropionitrile treatment, an overt mechanical disease state was not achieved as there were no differences in fracture toughness or 4 point bending due to β-aminopropionitrile treatment. While exercise did not alter (P = 0.058) the D-spacing distribution of collagen or prevent (P < 0.001) the β-aminopropionitrile-induced changes present in the unexercised animals, there were differential effects in the distribution of the reduced elastic modulus due to exercise between control and β-aminopropionitrile-treated animals (P < 0.001). Fracture toughness was increased (P = 0.043) as a main effect of exercise, but no significant differences due to exercise were observed using 4 point bending. Future studies should examine the potential for sex specific differences in the dose of β-aminopropionitrile required to induce mechanical effects in mice and the contributions of other nanoscale aspects of bone (e.g., the mineral–collagen interface) to elucidate the mechanism for the exercise-based improvements in fracture toughness observed here and the increased postyield deformation observed in other studies.

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“…It has been shown that treatment with BAPN decreases collagen cross-linking and myocardial stiffness in the left ventricle of normal adult pigs (32). Vicinal diamines (a certain kind of halogenated allyl amines), hydralazines, and aminoalkylaziridines with strict structural requirements are also inhibitors of LOX (17,47,48). Taurine, niacine, heparin, and 2-mercaptopyridine-N-oxide have been also reported as LOX inhibitors in vitro (1,19) and in vivo (3).…”

Section: Therapeutic Modulation Of Lox In Cardiac Diseasesmentioning

confidence: 99%

Role of lysyl oxidase in myocardial fibrosis: from basic science to clinical aspects

López

González

Hermida

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

224

198

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Because of its dynamic nature, the composition and structure of the myocardial collagen network can be reversibly modified to adapt to transient cardiac injuries. In response to persistent injury, however, irreversible, maladaptive changes of the network occur leading to fibrosis, mostly characterized by the excessive interstitial and perivascular deposition of collagen types I and III fibers. It is now becoming apparent that myocardial fibrosis directly contributes to adverse myocardial remodeling and the resulting alterations of left ventricular (LV) anatomy and function present in the major types of cardiac diseases. The enzyme lysyl oxidase (LOX) is a copper-dependent extracellular enzyme that catalyzes lysine-derived cross-links in collagen and elastin. LOXmediated cross-linking of collagen types I and III fibrils leads to the formation of stiff collagen types I and III fibers and their subsequent tissue deposition. Evidence from experimental and clinical studies shows that the excess of LOX is associated with an increased collagen cross-linking and stiffness. It is thus conceivable that LOX upregulation and/or overactivity could underlie myocardial fibrosis and altered LV mechanics and contribute to the compromise of LV function in cardiac diseases. This review will consider the molecular aspects related to the regulation and actions of LOX, namely, in the context of collagen synthesis. In addition, it will address the information related to the role of myocardial LOX in heart failure and the potential benefits of controlling its expression and function. collagen; diastolic dysfunction; hypertensive heart disease; myocardial remodeling THE ELEVATION IN myocardial stress that results from cardiac injury and/or persistent elevations in ventricular pressure or volume triggers a response of the myocardium in an attempt to return the tissue stress to its normal value. This response leads to progressive structural remodeling of the cardiomyocyte, vascular and extracellular matrix (ECM) components of the myocardium that manifest as changes in ventricular wall and chamber dimensions, as well as in diastolic and systolic function (5).Alterations in the myocardial collagen network are a hallmark of the ECM response to stress, either hemodynamic or nonhemodynamic in origin. A collagen network, composed largely of collagen types I and III fibers, is found in the interstitial space of the myocardium. Because collagen is a relatively stiff material with a high-tensile strength, small changes in its concentration have been shown to exert marked effects on the passive mechanical properties of the human heart (7). In addition to the concentration of collagen, experimental data suggest that the passive behavior of the myocardium may also be dependent on the relative proportion of the types of collagen, the diameter of the collagen fibers and their spatial alignment, and the degree of cross-linking. Accordingly, tissue containing predominantly type I collagen, large-diameter collagen fibers, and/or a high degree of cross-lin...

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Aminoalkylaziridines as substrates and inhibitors of lysyl oxidase specific inactivation of the enzyme by n- 5-aminopentyl aziridine

Abstract: Introduction 3. Materials and Methods 3.1. Enzyme purification and assay 4. Results 4.1 Substrate potential of aminoalkylaziridines 4.2 Competitive nature of inhibition 4.3 Irreversibility of inhibition 5. Discussion 6.. Acknowledgement 7. References

Cited by 12 publications

References 19 publications

β-Aminopropionitrile-Induced Reduction in Enzymatic Crosslinking Causes In Vitro Changes in Collagen Morphology and Molecular Composition

β-Aminopropionitrile-Induced Reduction in Enzymatic Crosslinking Causes In Vitro Changes in Collagen Morphology and Molecular Composition

Treadmill Exercise Improves Fracture Toughness and Indentation Modulus without Altering the Nanoscale Morphology of Collagen in Mice

Role of lysyl oxidase in myocardial fibrosis: from basic science to clinical aspects

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