scholarly journals Kinetics of creatine uptake in the perfused mouse liver: a 31P-n.m.r. study of transgenic mice expressing creatine kinase (CKBB) in the liver

1994 ◽  
Vol 303 (2) ◽  
pp. 531-538 ◽  
Author(s):  
S Masson ◽  
B Quistorff
Keyword(s):  
Creatine Kinase ◽  
Transgenic Mice ◽  
Mouse Liver ◽  
Biochemical Analysis ◽  
Perfused Liver ◽  
Creatine Uptake ◽  
Total Creatine ◽  
Kinetics Of ◽  
Dependent Mechanism

Transport of creatine in the mouse liver has been investigated in vivo and in the perfused organ. Experiments were carried out with transgenic mice expressing creatine kinase in the liver (brain isoenzyme CKBB; EC 7.2.3.2.) [Koretsky, Brosnan, Chen, Chen and Van Dyke (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 3112-3116] and in the corresponding control mice. The animals were fed a regular chow with or without the addition of 10% creatine (w/w) for 5 days. The kinetics of creatine uptake was measured in the perfused liver by 31P-n.m.r. spectroscopy and biochemical analysis following infusion of creatine at concentrations ranging over 0-15 mM and at an extracellular pH of either 7.40 or 6.40. The results suggest that creatine is actively transported by a pH-dependent mechanism obeying a saturable Michaelis-Menten type of kinetics (Km = 0.80 +/- 0.18 and 5.12 +/- 2.40 mM; Vmax. = 0.57 +/- 0.04 and 1.72 +/- 0.32 mumol.g of liver-1.min-1 at pH 7.40 and 6.40 respectively). Creatine export was evaluated in the perfused liver preloaded with creatine and the results show that less than 2.5 and 5% of the total creatine pool is exported to the perfusate during 80 min of perfusion at pH 7.40 and 6.40 respectively. Taken together, these results seem to explain the observation that creatine accumulates in the mouse liver only when blood creatine is raised by creatine feeding.

Different mechanisms in the attachment of cells to native and denatured collagen

1979 ◽  
Vol 38 (1) ◽  
pp. 267-281
Author(s):  
S.L. Schor ◽  
J. Court
Keyword(s):  
Cell Attachment ◽  
Experimental Conditions ◽  
Cell Matrix ◽  
Matrix Interactions ◽  
Independent Mechanism ◽  
Cell Matrix Interactions ◽  
Serum Dependent ◽  
Kinetics Of ◽  
Dependent Mechanism

The attachment of cells to collagen has been reported previously to require the presence of serum and the particular serum protein involved in this process, variously known as CIG, CAP or fibronectin, has been isolated. This conclusion that cell attachment to collagen requires serum (or more precisely, fibronectin) is based on experiments measuring the kinetics of cell attachment to films of collagen. We have measured the kinetics of attachment of HeLa and attachment to films of collagen-containing substrata under a variety of experimental conditions and present evidence that the serum-dependent mechanism of cell attachment described by others is actually only the case for films of denatured collagen, while cell attachment to native collagen fibres occurs by a different, serum-independent, mechanism. The possible relevance of these findings to cell-matrix interactions in vivo is discussed.

scholarly journals The Kinetics of In Vivo Priming of CD4 and CD8 T Cells by Dendritic/Tumor Fusion Cells in MUC1-Transgenic Mice

2002 ◽  
Vol 168 (5) ◽  
pp. 2111-2117 ◽  
Author(s):  
Shigeo Koido ◽  
Yasuhiro Tanaka ◽  
Dongshu Chen ◽  
Donald Kufe ◽  
Jianlin Gong
Keyword(s):  
T Cells ◽  
Transgenic Mice ◽  
Cd8 T Cells ◽  
Kinetics Of

scholarly journals Temporal and Spatial Resolution of Type I and III Interferon Responses In Vivo

2010 ◽  
Vol 84 (17) ◽  
pp. 8626-8638 ◽  
Author(s):  
Julia Elisabeth Pulverer ◽  
Ulfert Rand ◽  
Stefan Lienenklaus ◽  
Daniela Kugel ◽  
Natalia Ziętara ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Reporter Gene ◽  
Constitutive Expression ◽  
Type I ◽  
Type I Ifn ◽  
Limited Information ◽  
Activation Pattern ◽  
Type Iii ◽  
Kinetics Of

ABSTRACT Although the action of interferons (IFNs) has been extensively studied in vitro, limited information is available on the spatial and temporal activation pattern of IFN-induced genes in vivo. We created BAC transgenic mice expressing firefly luciferase under transcriptional control of the Mx2 gene promoter. Expression of the reporter with regard to onset and kinetics of induction parallels that of Mx2 and is thus a hallmark for the host response. Substantial constitutive expression of the reporter gene was observed in the liver and most other tissues of transgenic mice, whereas this expression was strongly reduced in animals lacking functional type I IFN receptors. As expected, the reporter gene was induced not only in response to type I (α and β) and type III (λ) IFNs but also in response to a variety of IFN inducers such as double-stranded RNA, lipopolysaccharide (LPS), and viruses. In vivo IFN subtypes show clear differences with respect to their kinetics of action and to their spatial activation pattern: while the type I IFN response was strong in liver, spleen, and kidney, type III IFN reactivity was most prominent in organs with mucosal surfaces. Infection of reporter mice with virus strains that differ in their pathogenicity shows that the IFN response is significantly altered in the strength of IFN action at sites which are not primarily infected as well as by the onset and duration of gene induction.

scholarly journals SOD1 aggregation in ALS mice shows simplistic test tube behavior

2015 ◽  
Vol 112 (32) ◽  
pp. 9878-9883 ◽  
Author(s):  
Lisa Lang ◽  
Per Zetterström ◽  
Thomas Brännström ◽  
Stefan L. Marklund ◽  
Jens Danielsson ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Protein Aggregation ◽  
Test Tube ◽  
Superoxide Dismutase 1 ◽  
Live Tissue ◽  
Antibody Assays ◽  
Kinetics Of ◽  
Aggregation Phenomena

A longstanding challenge in studies of neurodegenerative disease has been that the pathologic protein aggregates in live tissue are not amenable to structural and kinetic analysis by conventional methods. The situation is put in focus by the current progress in demarcating protein aggregation in vitro, exposing new mechanistic details that are now calling for quantitative in vivo comparison. In this study, we bridge this gap by presenting a direct comparison of the aggregation kinetics of the ALS-associated protein superoxide dismutase 1 (SOD1) in vitro and in transgenic mice. The results based on tissue sampling by quantitative antibody assays show that the SOD1 fibrillation kinetics in vitro mirror with remarkable accuracy the spinal cord aggregate buildup and disease progression in transgenic mice. This similarity between in vitro and in vivo data suggests that, despite the complexity of live tissue, SOD1 aggregation follows robust and simplistic rules, providing new mechanistic insights into the ALS pathology and organism-level manifestation of protein aggregation phenomena in general.

Phosphocreatine protects transgenic mouse liver expressing creatine kinase from hypoxia and ischemia

1993 ◽  
Vol 265 (6) ◽  
pp. C1544-C1551 ◽  
Author(s):  
K. Miller ◽  
J. Halow ◽  
A. P. Koretsky
Keyword(s):  
Creatine Kinase ◽  
Lactate Dehydrogenase ◽  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Intracellular Ph ◽  
Mouse Liver ◽  
Low Oxygen ◽  
Oxygen Stress ◽  
Atp Levels

Creatine kinase (CK) is normally found at high levels in muscle and brain and catalyzes the reaction phosphocreatine (PCr) + MgADP + H+<==>creatine (Cr) + MgATP. CK is not normally found at high levels in liver. A line of transgenic mice that express high levels of the BB-dimer of CK (CKB) in liver has allowed us to assess the role of CKB during periods of low oxygen stress. During 40 min of ischemia of normal perfused livers at 25 degrees C, ATP levels are depleted, and pH decreases to 6.6. pH recovers to a preischemic level after 30 min of reperfusion of normal livers; however, P(i) levels are significantly higher and ATP levels significantly lower than preischemic values. In transgenic liver with an initial PCr-to-ATP ratio of 4.5, ATP levels are maintained until PCr is markedly depleted. pH remains at preischemic levels for 16 min of ischemia of transgenic livers. During this length of ischemia in normal livers, pH has dropped to 6.9. pH, P(i), and ATP levels return to preischemic values within 30 min of reperfusion in transgenic livers containing PCr and CK. During 90 min of hypoxia of normal perfused livers at 37 degrees C, ATP is depleted. After 15 min of hypoxia of normal livers, there is a significant increase in the release of lactate dehydrogenase (LDH). In transgenic livers, ATP is maintained, and no increase in LDH release is observed for up to 90 min, depending on the level of PCr before hypoxia. These results demonstrate the role of CKB in buffering ATP levels and regulating intracellular pH during periods of low oxygen stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of functional mitochondrial creatine kinase in liver of transgenic mice

1997 ◽  
Vol 272 (4) ◽  
pp. C1193-C1202 ◽  
Author(s):  
K. Miller ◽  
K. Sharer ◽  
J. Suhan ◽  
A. P. Koretsky
Keyword(s):  
Creatine Kinase ◽  
Histochemical Staining ◽  
Mitochondrial Morphology ◽  
Resonance Spectroscopy ◽  
Intermembrane Space ◽  
Cellular Energetics ◽  
Mitochondrial Intermembrane Space ◽  
Total Creatine ◽  
Precise Role

The mitochondrial isoform of creatine kinase (MiCK) is localized to the mitochondrial intermembrane space, and its precise role in vivo is still actively being investigated. Here, we report a transgenic mouse model in which MiCK is expressed in liver, a tissue that does not normally express significant levels of CK. Expression of the genomic clone for human, ubiquitous MiCK was controlled by the promoter/enhancer region of the transthyretin gene. Three of seven founder mice were chosen to establish lines and had MiCK activity values ranging from 13 to 269 micromol x min(-1) x g wet wt(-1). Differential centrifugation and histochemical staining demonstrated that >90% of the CK activity is localized to the mitochondrial intermembrane space. An unusual mitochondrial morphology characterized by an angular nature to the membranes was detected using electron microscopy in the transgenic line expressing the highest levels of MiCK. Increasing hepatic total creatine levels led to a return to normal mitochondrial morphology. 31P-nuclear magnetic resonance spectroscopy demonstrated that the expressed MiCK is capable of producing and utilizing phosphocreatine. These mice will be useful for investigating gain of function effects of MiCK in cellular energetics.

scholarly journals Role of TLR4 in persistent Leptospira interrogans infection: a comparative in vivo study in mice

2020 ◽  
Author(s):  
Nisha Nair ◽  
Mariana Soares Guedes ◽  
Adeline Hajjar ◽  
Catherine Werts ◽  
Maria Gomes-Solecki
Keyword(s):  
Transgenic Mice ◽  
Sublethal Dose ◽  
Wild Type ◽  
Immune Markers ◽  
Lethal Infection ◽  
Tlr4 Gene ◽  
Kinetics Of ◽  
Tlr4 Receptor

AbstractToll-Like Receptor (TLR) 4, the LPS receptor, plays a central role in the control of leptospirosis and absence of TLR4 results in lethal infection in mice. Because human TLR4 does not sense the atypical leptospiral-LPS, we hypothesized that TLR4/MD-2 humanized transgenic mice (huTLR4) may be more susceptible to leptospirosis than wild-type mice, and thus may constitute a model of acute human leptospirosis. Therefore, we infected huTLR4 mice, which express human TLR4 but not murine TLR4, with a high but sublethal dose of L. interrogans serovar Copenhageni FioCruz (Leptospira) in comparison to C57BL/6J wildtype (WT) and, as a control, a congenic strain in which the tlr4 coding sequences are deleted (muTLR4Lps-del). We show that the huTLR4 gene is fully functional in the murine background. We found that dissemination of Leptospira in blood, shedding in urine, colonization of the kidney and overall kinetics of leptospirosis progression is equivalent between WT and huTLR4 C57BL/6J mice. Furthermore, inflammation of the kidney appeared to be subdued in huTLR4 compared to WT mice in that we observed less infiltrates of mononuclear lymphocytes, less innate immune markers and no relevant differences in fibrosis markers. Contrary to our hypothesis, huTLR4 mice showed less inflammation and kidney pathology, and are not more susceptible to leptospirosis than WT mice. This study is significant as it indicates that one intact TLR4 gene, be it mouse or human, is necessary to control acute leptospirosis.Contribution to the fieldDifferences of recognition exist between mouse and human TLR4, in that the anchor of LPS in the outer membrane of Leptospira (LipidA) activates murine, but not human TLR4. We hypothesized that if human TLR4 does not sense leptospiral-LPS, then transgenic mice in which murine TLR4 was replaced with human TLR4, should be more susceptible to Leptospira dissemination as compared to congenic wild-type mice, which could result in a more robust inflammatory response and pathology in the kidney. However, we found that impaired sensing of leptospiral-LPS in huTLR4 mice did not affect overall infection in comparison to wild-type mice and does not result in increased pathology of the kidney. Our study indicates that rather than leptospiral-LPS sensing, the presence of a fully functional TLR4 receptor is necessary to control acute leptospirosis.

Maturational changes in respiratory control through creatine kinase in heart in vivo

1992 ◽  
Vol 263 (2) ◽  
pp. C453-C460 ◽  
Author(s):  
M. A. Portman ◽  
X. H. Ning
Keyword(s):  
Creatine Kinase ◽  
Oxygen Consumption ◽  
Kinase Activity ◽  
Respiratory Control ◽  
Atp Synthesis ◽  
Developmental State ◽  
Creatine Kinase Activity ◽  
Total Creatine Kinase Activity ◽  
Total Creatine

The role of creatine kinase in regulation of myocardial respiration was studied in vivo as a function of maturation. Unidirectional creatine kinase flux (JCK), phosphocreatine to gamma-ATP, was measured in newborn lambs (age 3-9 days, n = 8) and mature sheep (age 30-60 days, n = 6) using 31P saturation transfer techniques, and total creatine kinase activity was measured using standard methods. Myocardial oxygen consumption (MVO2) was measured simultaneously via an extracorporeal shunt from the coronary sinus as cardiac work was increased via epinephrine (1-3 micrograms.kg-1.min-1). Findings were as follows: 1) baseline newborn JCK was markedly lower than in mature sheep despite higher levels of MVO2, and this could be related to a decrease in total creatine kinase activity; 2) JCK was substantially higher than the rate of ATP synthesis in both groups at baseline rates of oxygen consumption; and 3) JCK decreased significantly in newborns during increases in MVO2, whereas there was no change in flux rate in the mature sheep during even larger relative changes in work and oxygen consumption. These data imply that creatine kinase does not limit oxidative phosphorylation. However, this enzyme system probably maintains at least an indirect role in respiratory control that is a function of the myocardial developmental state.

Sign in / Sign up

Export Citation Format

Share Document