scholarly journals Insights into Wild-Type and Mutant p53 Functions Provided by Genetically Engineered Mice

2014 ◽  
Vol 35 (6) ◽  
pp. 715-727 ◽  
Author(s):  
Lawrence A. Donehower
Keyword(s):  
Genetically Engineered ◽  
Mutant P53 ◽  
Wild Type ◽  
Genetically Engineered Mice

The α2-isoform of Na-K-ATPase mediates ouabain-induced hypertension in mice and increased vascular contractility in vitro

2005 ◽  
Vol 288 (2) ◽  
pp. H477-H485 ◽  
Author(s):  
Iva Dostanic ◽  
Richard J. Paul ◽  
John N. Lorenz ◽  
Steven Theriault ◽  
James W. Van Huysse ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Left Ventricular ◽  
Genetically Engineered ◽  
Wild Type ◽  
Vascular Contractility ◽  
Genetically Engineered Mice ◽  
Basal Tone ◽  
Induced Hypertension ◽  
Spontaneous Contractions

Although ouabain is known to induce hypertension, the mechanism of how this cardiac glycoside affects blood pressure is uncertain. The present study demonstrates that the α2-isoform of the Na-K-ATPase mediates the pressor effects of ouabain in mice. To accomplish this, we analyzed the effect of ouabain on blood pressure in wild-type mice, where the α2-isoform is sensitive to ouabain, and genetically engineered mice expressing a ouabain-insensitive α2-isoform of the Na-K-ATPase. Thus differences in the response to ouabain between these two genotypes can only be attributed to the α2-isoform of Na-K-ATPase. As the α1-isoform is naturally resistant to ouabain in rodents, it will not be inhibited by ouabain in either genotype. Whereas prolonged administration of ouabain increased levels of ouabain in serum from both wild-type and targeted animals, hypertension developed only in wild-type mice. In addition, bolus intravenous infusion of ouabain increased the systolic, mean arterial, and left ventricular blood pressure in only wild-type anesthetized mice. In vitro, ouabain increased vascular tone and thereby phenylephrine-induced contraction of the aorta in intact and endothelium-denuded wild-type mice but in α2-resistant mice. Ouabain also increased the magnitude of the spontaneous contractions of portal vein and the basal tone of the intact aorta from only wild-type mice. The increase in aortic basal tone was dependent on the presence of endothelium. Our studies also demonstrate that the α2-isoform of Na-K-ATPase mediates the ouabain-induced increase in vascular contractility. This could play a role in the development and maintenance of ouabain-induced hypertension.

Lack of neurokinin-1 receptor expression affects tissue mast cell numbers but not their spatial relationship with nerves

2005 ◽  
Vol 288 (2) ◽  
pp. R491-R500 ◽  
Author(s):  
Michael R. D'Andrea ◽  
Marcia R. Saban ◽  
Norma P. Gerard ◽  
Barry K. Wershil ◽  
Ricardo Saban
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Spatial Association ◽  
Spatial Relationship ◽  
Genetically Engineered ◽  
Receptor Expression ◽  
Wild Type ◽  
Genetically Engineered Mice ◽  
Neurokinin 1 ◽  
Anatomic Relationship

A spatial association between mast cells and nerves has been described in both the gastrointestinal and genitourinary tracts. However, the factors that influence the anatomic relationship between mast cells and nerves have not been completely defined. It has been suggested that the high-affinity receptor for substance P [neurokinin-1 (NK1)] might modulate this interaction. We therefore assessed mast cell-nerve relationships in tissues isolated from wild-type and NK1 receptor knockout (NK1−/−) mice. We now report that, in the complete absence of NK1 receptor expression, there is a significant increase in the number of mast cells without a change in the anatomic relationship between mast cell and nerves in stomach and bladder tissues at the light microscopic level. We next determined whether transplanted mast cells would maintain their spatial distribution, number, and contact with nerve elements. For this purpose, mast cell-deficient Kit W /Kit W−v mice were reconstituted with wild-type or NK1−/− bone marrow. No differences in mast cell-nerve contact were observed. These results suggest that NK1 receptor expression is important in the regulation of the number of mast cells but is not important in the interaction between mast cells and nerves. Furthermore, the interaction between mast cells and nerves is not mediated through NK1 receptor expression on the mast cell. Further studies are needed to determine the molecular pathway involved in mast cell migration and interaction with nerve elements, but the model of reconstitution of Kit W /Kit W−v mice with mast cells derived from different genetically engineered mice is a useful approach to further explore these mechanisms.

bFGF ameliorates focal ischemic injury by blood flow-independent mechanisms in eNOS mutant mice

1997 ◽  
Vol 272 (3) ◽  
pp. H1401-H1405 ◽  
Author(s):  
Z. Huang ◽  
K. Chen ◽  
P. L. Huang ◽  
S. P. Finklestein ◽  
M. A. Moskowitz
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Infarct Volume ◽  
Genetically Engineered ◽  
Mutant Mice ◽  
Neurological Deficits ◽  
Wild Type ◽  
Doppler Flowmetry ◽  
Mca Occlusion ◽  
Genetically Engineered Mice

Genetically engineered mice deficient in the expression of type III nitric oxide synthase (NOS) [endothelial NOS (eNOS)] were used to decipher the importance of nitric oxide (NO)-dependent augmentation of regional cerebral blood flow (rCBF) to infarct volume reduction following basic fibroblast growth factor (bFGF) infusion during acute middle cerebral artery (MCA) occlusion. We have shown previously that intravenously administered bFGF reduces infarct volume following MCA occlusion in rats and that bFGF dilates cerebral pial arterioles by NO-dependent mechanisms. Halothane-anesthetized eNOS knockout and wild-type mice were subjected to permanent MCA occlusion by intraluminal filament for 24 h. bFGF (100 microg x kg(-1) x h(-1)) was infused intravenously for 2 h, beginning 15 min after the onset of occlusion. Infarct volume was reduced from 119 +/- 8 to 93 +/- 4 mm3 (22% reduction, P < 0.05) or from 102 +/- 9 to 77 +/- 6 mm3 (24% reduction, P < 0.05) in eNOS knockout or wild-type mice, respectively (means +/- SE; n = 10 per group), and neurological deficits were also significantly reduced. Although bFGF infusion caused a 27% increase in rCBF and a 17% reduction in vascular resistance in the infarct margin of wild-type animals as measured by laser Doppler flowmetry, bFGF did not enhance rCBF in the infarct margin of eNOS mutant mice. These data indicate that intravenous bFGF reduces infarct volume following focal ischemia by mechanisms that are largely blood flow independent.

Formation of Platelet Strings and Microthrombi in the Presence of ADAMTS13 Inhibitor Does Not Require P-Selectin or β3 Integrin.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1782-1782
Author(s):  
Anil K. Chauhan ◽  
Denisa D. Wagner
Keyword(s):  
Calcium Ionophore ◽  
Genetically Engineered ◽  
Ionophore A23187 ◽  
Type I ◽  
Wild Type ◽  
Endothelial Surface ◽  
Genetically Engineered Mice ◽  
Β3 Integrin ◽  
Mean Time

Abstract VWF is synthesized in megakaryocytes and endothelial cells and stored in a-granules and Weibel-Palade bodies respectively. VWF released from the storage granules upon cellular activation or stimulation with secretagogues are extremely large and known as Ultra-Large von Willebrand factor (UL-VWF). Such filaments were first shown by Dong and colleagues (Dong et. al., 2002) and platelets were seen to align as string of beads on these UL-VWF multimers. These platelet strings are then rapidly cleaved to smaller size by the metalloprotease ADAMTS-13 (A Disintegrin-like And Metalloprotease with Thrombospondin type I repeats-13). Recently, we have similarly shown that in Adamts13−/− mice platelet strings form and remain on stimulated endothelium in veins, where they wave in the blood stream for many minutes (Motto et. al., 2005). We have also shown that antibody to ADAMTS13 induces platelet strings in activated venules and transient thrombi formation in activated microvenules of wild type similar to Adamts13−/− mice (Chauhan et. al., 2006). The obvious question is what anchors the UL-VWF mulimers to the endothelial surface? In a flow chamber model, using polyclonal antibodies to P-selectin or soluble P-selectin, it was proposed that P-selectin anchors the UL-VWF multimers to the endothelial surface. The present study was designed to address the role of P-selectin and that of the platelet and endothelial integrin β3 in platelet string formation in vivo using intravital microscopy and genetically engineered mice. We demonstrate that in histamine activated venules, causing Weibel-Palade bodies secretion, P-selectin is not required for formation or retention of VWF platelet strings on endothelium in vivo. The mean time the platelet strings (~30–100 μm long) anchored onto the endothelium was 45 s. This duration was significantly longer than in P-selectin−/− mice infused with control Ig (P&lt;0.001) and similar to WT mice treated with the inhibitory antibody. Similar to wild type, 45 s after topical superfusion of calcium ionophore A23187, platelet strings forming transient thrombi formation was seen in microvenules (25–30 μm in diameter) of P-selectin−/− mice when the ADAMTS13 activity was inhibited. Platelet strings were either not seen or were very short lived in the β3−/− mice infused with control Ig, whereas in the mice infused with anti- ADAMTS13 antibody platelet strings could be seen that anchored to the endothelium with a mean time of 50 s (P&lt;0.0001). These observations show that platelet strings are not held by β3 integrin and platelets lacking β3 integrin can adhere firmly to the VWF strings in the histamine activated venules. VWF containing platelet strings could also entangle and form emboli in the absence of β3 integrin.

scholarly journals Mesotheliomas in Genetically Engineered Mice Unravel Mechanism of Mesothelial Carcinogenesis

2018 ◽  
Vol 19 (8) ◽  
pp. 2191 ◽  
Author(s):  
Didier Jean ◽  
Marie-Claude Jaurand
Keyword(s):  
Malignant Mesothelioma ◽  
Asbestos Exposure ◽  
Genetically Engineered ◽  
Health Concern ◽  
Molecular Profile ◽  
Tumour Suppressor Genes ◽  
Wild Type ◽  
Genetically Engineered Mice ◽  
Bona Fide

Malignant mesothelioma (MM), a rare and severe cancer, mainly caused as a result of past-asbestos exposure, is presently a public health concern. Current molecular studies aim to improve the outcome of the disease, providing efficient therapies based on the principles of precision medicine. To model the molecular profile of human malignant mesothelioma, animal models have been developed in rodents, wild type animals and genetically engineered mice harbouring mutations in tumour suppressor genes, especially selecting genes known to be inactivated in human malignant mesothelioma. Animals were either exposed or not exposed to asbestos or to other carcinogenic fibres, to understand the mechanism of action of fibres at the molecular level, and the role of the selected genes in mesothelial carcinogenesis. The aim of the manuscript was to compare mesothelioma models to human malignant mesothelioma and to specify the clue genes playing a role in mesothelial carcinogenesis. Collectively, MM models recapitulate the clinical features of human MM. At least two altered genes are needed to induce malignant mesothelioma in mice. Two pathways regulated by Cdkn2a and Trp53 seem independent key players in mesothelial carcinogenesis. Other genes and pathways appear as bona fide modulators of the neoplastic transformation.

scholarly journals Colorectal cancers utilize glutamine as an anaplerotic substrate of the TCA cycle in vivo

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yiqing Zhao ◽  
Xuan Zhao ◽  
Vanessa Chen ◽  
Ying Feng ◽  
Lan Wang ◽  
...  
Keyword(s):  
Tca Cycle ◽  
Genetically Engineered ◽  
Glutamine Metabolism ◽  
Colorectal Cancers ◽  
Wild Type ◽  
Colon Tumors ◽  
The Tca Cycle ◽  
Genetically Engineered Mice ◽  
Tca Cycle Intermediates

AbstractCancer cells in culture rely on glutamine as an anaplerotic substrate to replenish tricarboxylic acid (TCA) cycle intermediates that have been consumed. but it is uncertain whether cancers in vivo depend on glutamine for anaplerosis. Here, following in vivo infusions of [13C5]-glutamine in mice bearing subcutaneous colon cancer xenografts, we showed substantial amounts of infused [13C5]-glutamine enters the TCA cycle in the tumors. Consistent with our prior observation that colorectal cancers (CRCs) with oncogenic mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic (PIK3CA) subunit are more dependent on glutamine than CRCs with wild type PIK3CA, labeling from glutamine to most TCA cycle intermediates was higher in PIK3CA-mutant subcutaneous xenograft tumors than in wild type PIK3CA tumors. Moreover, using orthotopic mouse colon tumors estalished from human CRC cells or patient-derived xenografts, we demonstrated substantial amounts of infused [13C5]-glutamine enters the TCA cycle in the tumors and tumors utilize anaplerotic glutamine to a greater extent than adjacent normal colon tissues. Similar results were seen in spontaneous colon tumors arising in genetically engineered mice. Our studies provide compelling evidence CRCs utilizes glutamine to replenish the TCA cycle in vivo, suggesting that targeting glutamine metabolism could be a therapeutic approach for CRCs, especially for PIK3CA-mutant CRCs.

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