Effect of monocrotaline pyrrole on cultured cell cytoskeletons: An ultrastructural study

1991 ◽  
Vol 49 ◽  
pp. 122-123
Author(s):  
J.I. Wood ◽  
K.L. Klomparens ◽  
C.M. Hoorn ◽  
R.A. Roth ◽  
J. Reindel
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Cell Division ◽  
Alkylating Agent ◽  
Pyrrolizidine Alkaloid ◽  
Cell Structure ◽  
Plant Toxin ◽  
Monocrotaline Pyrrole ◽  
Intracellular Motility

The cytoskeleton (CS) is responsible for locomotion, intracellular motility and maintenance of cell structure. The system is composed of three major components: microfilaments, responsible for motility and cell structure, microtubules for organization and movement within the cell, and intermediate filaments, which may provide stability of intracellular contents.Monocrotaline (MCT) is a pyrrolizidine alkaloid plant toxin. When administered to rats, MCT is metabolized to monocrotaline pyrrole (MCTP) which induces lung injury and pulmonary hypertension. When administered to cultured pulmonary artery endothelial cells, MCTP causes progressive detachment, release of LDH, inhibition of cell proliferation, and distorted and enlarged nuclei. MCTP is a bifunctional alkylating agent that can crosslink DNA. We speculate that MCTP may also affect the cytoskeleton, resulting in inhibition of cell division.

Morphologic alterations in porcine endothelial cells by the plant toxin metabolite, monocrotaline pyrrole

1990 ◽  
Vol 48 (3) ◽  
pp. 822-823
Author(s):  
M.E. Hogan ◽  
J.G. Wagner ◽  
K.L. Klomparens ◽  
R.A. Roth
Keyword(s):  
Endothelial Cells ◽  
Pyrrolizidine Alkaloid ◽  
Tissue Cultures ◽  
Interstitial Edema ◽  
Plant Toxin ◽  
Porcine Endothelial Cells ◽  
Monocrotaline Pyrrole ◽  
Primary Tissue ◽  
Scanning Electron ◽  
Millipore Filters

Animals treated with the pyrrolizidine alkaloid metabolite, monocrotaline pyrrole (MCTP), show a progressive pulmonary hypertension associated with interstitial edema and smooth muscle thickening of muscular vessels in the lung. To determine what effect the blood borne toxin has on the endothelium, primary tissue cultures were treated with MCTP and were examined using the scanning electron microscope.Porcine endothelial cells were isolated, cultured, then plated on tissue culture slides and Millipore filters. The effect of cell density was examined by plating at three different concentrations, the most dense (control cells) being confluent at time of fixation. Cells received no treatment, the vehicle (N,Ndimethylformamide), 5μg MCTP/ml or 50μg MCTP/ml 24 hours after plating and were allowed to grow for an additional four days.The most striking changes were cell hypertrophy and an alteration in the cell's plating character at a dose of 50μg MCTP/ml. Hypertrophy of the endothelial cells was evident at the 50μg MCTP/ml dose, at which the treated cells approached 4 to 5 times the size of the untreated cells.

scholarly journals Critical Role of Caveolin-1 Loss/Dysfunction in Pulmonary Hypertension

2021 ◽  
Vol 9 (4) ◽  
pp. 58
Author(s):  
Rajamma Mathew
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Membrane Protein ◽  
Critical Role ◽  
High Morbidity ◽  
Caveolin 1 ◽  
Enhanced Expression ◽  
Medial Hypertrophy

Pulmonary hypertension (PH) is a rare disease with a high morbidity and mortality rate. A number of systemic diseases and genetic mutations are known to lead to PH. The main features of PH are altered vascular relaxation responses and the activation of proliferative and anti-apoptotic pathways, resulting in pulmonary vascular remodeling, elevated pulmonary artery pressure, and right ventricular hypertrophy, ultimately leading to right heart failure and premature death. Important advances have been made in the field of pulmonary pathobiology, and several deregulated signaling pathways have been shown to be associated with PH. Clinical and experimental studies suggest that, irrespective of the underlying disease, endothelial cell disruption and/or dysfunction play a key role in the pathogenesis of PH. Endothelial caveolin-1, a cell membrane protein, interacts with and regulates several transcription factors and maintains homeostasis. Disruption of endothelial cells leads to the loss or dysfunction of endothelial caveolin-1, resulting in reciprocal activation of proliferative and inflammatory pathways, leading to cell proliferation, medial hypertrophy, and PH, which initiates PH and facilitates its progression. The disruption of endothelial cells, accompanied by the loss of endothelial caveolin-1, is accompanied by enhanced expression of caveolin-1 in smooth muscle cells (SMCs) that leads to pro-proliferative and pro-migratory responses, subsequently leading to neointima formation. The neointimal cells have low caveolin-1 and normal eNOS expression that may be responsible for promoting nitrosative and oxidative stress, furthering cell proliferation and metabolic alterations. These changes have been observed in human PH lungs and in experimental models of PH. In hypoxia-induced PH, there is no endothelial disruption, loss of endothelial caveolin-1, or enhanced expression of caveolin-1 in SMCs. Hypoxia induces alterations in membrane composition without caveolin-1 or any other membrane protein loss. However, caveolin-1 is dysfunctional, resulting in cell proliferation, medial hypertrophy, and PH. These alterations are reversible upon removal of hypoxia, provided there is no associated EC disruption. This review examined the role of caveolin-1 disruption and dysfunction in PH.

Characterization of monocrotaline pyrrole-induced DNA cross-linking in pulmonary artery endothelium

1993 ◽  
Vol 264 (5) ◽  
pp. L517-L522 ◽  
Author(s):  
J. G. Wagner ◽  
T. W. Petry ◽  
R. A. Roth
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Pulmonary Vasculature ◽  
Cross Linking ◽  
Toxic Metabolite ◽  
Dependent Manner ◽  
Inhibition Of Proliferation ◽  
Monocrotaline Pyrrole

Monocrotaline pyrrole (MCTP) is a putative, toxic metabolite of the pyrrolizidine alkaloid, monocrotaline (MCT). When given intravenously to rats, it produces a delayed and progressive injury to the vasculature of the lungs that results in pulmonary hypertension and right heart hypertrophy. Dysfunctional endothelium and vascular leak are early signs of overt injury to the lung. When administered to endothelial cell cultures, MCTP causes cell enlargement, delayed and progressive cytotoxicity, and inhibition of proliferation in surviving cells. MCTP is a bifunctional alkylating agent which binds to DNA and other macromolecules. To examine DNA-MCTP interactions in endothelium, MCTP-induced DNA cross-linking was characterized in cultures of porcine endothelial cells (PECs) derived from pulmonary artery. MCTP caused DNA cross-linking in a dose-dependent manner that was consistent with its ability to inhibit cell proliferation. PECs exposed to MCTP for 48 h developed cross-linking that was maximal at 2 days and remained significant through 10 days. Increasing the duration of PEC exposure to the medium to which MCTP had been added was associated with increased DNA cross-linking. These results indicate that MCTP causes DNA cross-linking, which may explain the inhibition of cell proliferation observed in pulmonary endothelial cells in vitro. The long-lasting nature of DNA cross-linking and its dose relatedness are consistent with the delayed and progressive effects of MCTP on endothelial cells in vitro and on pulmonary vasculature in vivo.

scholarly journals Monocrotaline pyrrole induces pulmonary endothelial damage through binding to and release from erythrocytes in lung during venous blood reoxygenation

2019 ◽  
Vol 316 (5) ◽  
pp. L798-L809 ◽  
Author(s):  
Rui Xiao ◽  
Liping Zhu ◽  
Yuan Su ◽  
Jiwei Zhang ◽  
Yankai Lu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Partial Pressure ◽  
Venous Blood ◽  
Endothelial Damage ◽  
Toxic Metabolite ◽  
Partial Pressure Of Oxygen ◽  
Standard Dosage ◽  
Arterial Blood ◽  
Monocrotaline Pyrrole

Monocrotaline has been widely used to establish an animal model of pulmonary hypertension, most frequently in rats. An important feature of this model resides in the selectivity of monocrotaline injury toward the pulmonary vascular endothelium versus the systemic vasculature when administrated at standard dosage. The toxic metabolite of monocrotaline, monocrotaline pyrrole, is transported by erythrocytes. This study aimed to reveal whether partial pressure of oxygen of blood determined the binding and release of monocrotaline pyrrole from erythrocytes in rats with one subcutaneous injection of monocrotatline at the standard dosage of 60 mg/kg. Our experiments demonstrated that monocrotaline pyrrole bound to and released from erythrocytes at the physiological levels of partial pressure of oxygen in venous and arterial blood, respectively, and then aggregated on pulmonary artery endothelial cells. Monocrotaline pyrrole-induced damage of endothelial cells was also dependent on partial pressure of oxygen. In conclusion, our results demonstrate the importance of oxygen partial pressure on monocrotaline pyrrole binding to erythrocytes and on aggregation and injury of pulmonary endothelial cells. We suggest that these mechanisms contribute to pulmonary selectivity of this toxic injury model of pulmonary hypertension.

Hypoxia increases AP-1 binding activity by enhancing capacitative Ca2+ entry in human pulmonary artery endothelial cells

2003 ◽  
Vol 285 (6) ◽  
pp. L1233-L1245 ◽  
Author(s):  
Ivana Fantozzi ◽  
Shen Zhang ◽  
Oleksandr Platoshyn ◽  
Carmelle V. Remillard ◽  
Randy T. Cowling ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Transcription Factors ◽  
Pulmonary Artery ◽  
Transient Receptor Potential ◽  
Chronic Hypoxia ◽  
Receptor Potential ◽  
Binding Activity

Activating protein (AP)-1 transcription factors modulate expression of genes involved in cell proliferation and migration. Chronic hypoxia increases pulmonary artery smooth muscle cell proliferation by upregulating AP-1-responsive genes encoding for endothelium-derived vasoactive and mitogenic factors implicated in pulmonary hypertension development. The expression of AP-1 transcription factors is sensitive to changes in cytosolic free [Ca2+] ([Ca2+]cyt). Capacitative Ca2+ entry (CCE) via store-operated Ca2+ channels (SOC) is an important mechanism for raising [Ca2+]cyt in pulmonary artery endothelial cells (PAEC). Using combined molecular biological, fluorescence microscopy, and biophysical approaches, we examined the effect of chronic hypoxia (3% O2, 72 h) on AP-1 DNA binding activity, CCE, and transient receptor potential (TRP) gene expression in human (h) PAEC. EMSA showed that AP-1 binding to hPAEC nuclear protein extracts was significantly enhanced by hypoxia, the increase being dependent on store-operated Ca2+ influx and sensitive to La3+, an SOC inhibitor. Hypoxia also increased basal [Ca2+]cyt, the amount of CCE produced by store depletion with cyclopiazonic acid, and the amplitude of SOC-mediated currents ( ISOC). The increases of CCE amplitude and ISOC current density by hypoxia were paralleled by enhanced TRPC4 mRNA and protein expression. Hypoxia-enhanced CCE and TRPC4 expression were also attenuated by La3+. These data suggest that hypoxia increases AP-1 binding activity by enhancing Ca2+ influx via La3+-sensitive TRP-encoded SOC channels in hPAEC. The Ca2+-mediated increase in AP-1 binding may play an important role in upregulating AP-1-responsive gene expression, in stimulating pulmonary vascular cell proliferation and, ultimately, in pulmonary vascular remodeling in patients with hypoxia-mediated pulmonary hypertension.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

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