scholarly journals Mineralocorticoid receptor knockout mice: Pathophysiology of Na+ metabolism

1998 ◽  
Vol 95 (16) ◽  
pp. 9424-9429 ◽  
Author(s):  
Stefan Berger ◽  
Markus Bleich ◽  
Wolfgang Schmid ◽  
Timothy J. Cole ◽  
Jörg Peters ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Mineralocorticoid Receptor ◽  
Transcriptional Control ◽  
Plasma Concentrations ◽  
Prenatal Development ◽  
Strong Increase ◽  
Rnase Protection ◽  
Transepithelial Voltage ◽  
Deficient Mice

Mineralocorticoid receptor (MR)-deficient mice were generated by gene targeting. These animals had a normal prenatal development. During the first week of life, MR-deficient (−/−) mice developed symptoms of pseudohypoaldosteronism. They finally lost weight and eventually died at around day 10 after birth from dehydration by renal sodium and water loss. At day 8, −/− mice showed hyperkalemia, hyponatremia, and a strong increase in renin, angiotensin II, and aldosterone plasma concentrations. Methods were established to measure renal clearance and colonic transepithelial Na+ reabsorption in 8-day-old mice in vivo. The fractional renal Na+ excretion was elevated >8-fold. The glomerular filtration rate in −/− mice was not different from controls. The effect of amiloride on renal Na+ excretion and colonic transepithelial voltage reflects the function of amiloide-sensitive epithelial Na+ channels (ENaC). In −/− mice, it was reduced to 24% in the kidney and to 16% in the colon. There was, however, still significant residual ENaC-mediated Na+ reabsorption in both epithelia. RNase protection analysis of the subunits of ENaC and (Na++ K+)-ATPase did not reveal a decrease in −/− mice. The present data indicate that MR-deficient neonates die because they are not able to compensate renal Na+ loss. Regulation of Na+ reabsorption via MR is not achieved by transcriptional control of ENaC and (Na+ + K+)-ATPase in RNA abundance but by transcriptional control of other as yet unidentified genes. MR knockout mice will be a suitable tool for the search of these genes.

A Novel Role of Coagulation Proteases on Viral-Based Gene Transfer Efficacy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 691-691
Author(s):  
Joerg Schuettrumpf ◽  
Jianxiang Zou ◽  
Shin Jen Tai ◽  
Alexander Schlachterman ◽  
Kian Tian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Transfer ◽  
Knockout Mice ◽  
Viral Vectors ◽  
Hemophilia B ◽  
Gene Copy ◽  
Dependent Manner ◽  
Deficient Mice

Abstract Coagulation proteases are crucial for hemostasis and have also been implicated in inflammatory responses, blood vessel formation, and tumor cell metastasis. Cellular responses triggered by proteases are mediated by protease-activated receptors (PAR). Adeno-associated virus (AAV)-2 vectors hold promise for the treatment of several diseases and were already tested in Phase I studies for hemophilia B following intramuscular or hepatic artery deliveries. Previously, we determined an unexpected inhibitory effect (60–70% downregulation) on AAV-2 and adenovirus mediated gene transfer by thrombin- or FXa inhibitors. These results were independent of mouse strain, transgene product, or vector promoter, and gene expression by vectors of alternate serotypes AAV-5 or -8, which do not share cellular receptors with AAV-2, were not affected by any drug. Here we present in vivo evidence of a novel role of coagulation proteases and PARs in modulating gene transfer by viral vectors. We tested AAV-2 gene transfer efficacy in (a) animal models for proteases deficiency [FX and FIX deficient animals], (b) PAR-1 or PAR-2 deficient mice, (c) and following in vivo activation of PARs. FX knockout mice with residual activity of only 1–3% of normal (n=9) were injected with AAV-2-human(h)FIX vector and compared to littermates with FX levels of 50% (n=4). FIX expression levels were 2-fold lower among FX-deficient mice compared to controls (p<0.03). The second model, FIX deficient mice, received AAV expressing α1-antitrypsin (AAT-1). Severe hemophilia B models due to large-gene deletion (n=5) or missense mutation (R180T) in the FIX gene (n=3, <1% FIX) were compared to littermate controls with normal FIX levels (n=6). The results showed that AAT-1 levels among hemophilia B mice were 2-fold lower than in controls (24 vs 48 ng/ml, p<0.05, respectively). Because PAR activation by thrombin enhances αVβ5 (co-receptor for AAV-2 and adenovirus)-dependent cellular function (JBC 276:10952) we hypothesized that PAR modulates AAV-2 gene transfer. Homozygous (−/−) or heterozygous deficient (+/−) PAR-1 (n=24) or PAR-2 (n=25) mice received AAV-2-hF.IX and were compared to littermate controls (+/+). FIX levels among PAR-1 controls (1.9 μg/ml) were comparable to levels obtained among heterozygotes but higher than in homozygotes (1.1 μg/ml, p<0.02). Similarly, PAR-2 deficient mice presented 2-fold lower FIX levels than controls (0.7 vs 1.3 μg/ml, p<0.02) whereas heterozygous mice presented intermediate levels. To further confirm the role of PARs in AAV-2 gene transfer we activated PARs prior to AAV-2 injection. C57BL/6 mice received specific peptide agonists at doses ranging from 10 to 60 μM/kg (n=4 per dose and per peptide) and were compared to controls receiving scramble peptide. FIX levels increased 1.5 to 5-fold in a dose-dependent manner and the activation of PAR-1 and -2 simultaneously was superior to single peptide. Gene copy monitoring revealed low vector uptake by livers of PAR knockout mice while activation of PARs increased uptake. In conclusion, these data demonstrated a novel in vivo role of coagulation proteases and PARs on viral vectors (AAV-2 and adenovirus)-mediated gene expression and provide an alternative target to modulate gene therapy strategies.

scholarly journals Caspase-3/NLRP3 signaling in the mesenchymal stromal niche regulates myeloid-biased hematopoiesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Zhang ◽  
Yaozhen Chen ◽  
Dandan Yin ◽  
Fan Feng ◽  
Qunxing An ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Knockout Mice ◽  
Caspase 3 ◽  
Ex Vivo ◽  
Gene Knockout ◽  
Hematopoietic Stem ◽  
Nlrp3 Gene ◽  
Gene Knockout Mice ◽  
Deficient Mice

Abstract Background The fate of hematopoietic stem cells (HSCs) is determined by a complex regulatory network that includes both intrinsic and extrinsic signals. In the past decades, many intrinsic key molecules of HSCs have been shown to control hematopoiesis homeostasis. Non-hematopoietic niche cells also contribute to the self-renewal, quiescence, and differentiation of HSCs. Mesenchymal stromal cells (MSCs) have been identified as important components of the niche. However, the regulatory role of MSCs in hematopoiesis has not been fully understood. Methods Caspase-3 and NLRP3 gene knockout mice were generated respectively, and hematopoietic development was evaluated in the peripheral circulation and bone marrow by flow cytometry, colony formation assay, and bone marrow transplantation. Bone-associated MSCs (BA-MSCs) were then isolated from gene knockout mice, and the effect of Caspase-3/NLRP3 deficient BA-MSCs on hematopoiesis regulation was explored in vivo and ex vivo. Results We report that Caspase-3 deficient mice exhibit increased myelopoiesis and an aberrant HSC pool. Ablation of Caspase-3 in BA-MSCs regulates myeloid lineage expansion by altering the expression of hematopoietic retention cytokines, including SCF and CXCL12. Interestingly, NLRP3 gene knockout mice share phenotypic similarities with Caspase-3 deficient mice. Additionally, we found that NLRP3 may play a role in myeloid development by affecting the cell cycle and apoptosis of hematopoietic progenitors. Conclusions Our data demonstrate that the Caspase-3/NLRP3 signaling functions as an important regulator in physiological hematopoiesis, which provides new insights regarding niche signals that influence hematopoiesis regulation in the bone marrow.

Abstract 5290: Cypher Long but not Short Isoform Specific Knockout Mice Result in Cardiac Signaling Defects and Dilated Cardiomyopathy

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Hongqiang Cheng ◽  
Ming Zheng ◽  
Farah Sheikh ◽  
Kunfu Ouyang ◽  
Li Cui ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Heart Function ◽  
Gene Mutations ◽  
Splice Isoforms ◽  
Functional Roles ◽  
Deficient Mice

Our previous studies have demonstrated that Cypher, a PDZ-LIM protein localized at the Z line, plays a pivotal role in heart function. We recently identified long and short splice isoforms of Cypher, which are characterized by the presence and absence of LIM domains, respectively. The LIM domain of Cypher is thought to be involved in signaling, based on its ability to directly interact with signaling proteins. In human patients with dilated cardiomyopathy (DCM) we discovered Cypher gene mutations, which affect either long or short isoform or both isoforms. However, the precise molecular mechanisms underlying the role of Cypher isoforms in DCM remain unclear. To determine the role of Cypher isoforms in cardiac signaling and disease in vivo , we generated two Cypher isoform specific knockout mice. Selective ablation of Cypher long isoforms in mice resulted in partial neonatal lethality. However, hearts from viable Cypher long isoform deficient mice displayed Z line abnormalities and decreased cardiomyocyte widths, which resulted in a progressive form of DCM, characterized by fibrosis, calcification and lethality. The effects on cardiac function and disease observed in long-isoform specific Cypher knockout mice were preceded by significant decreases in cardiac protein kinase C and extracellular signal-regulated kinase signaling. These results are in contrast to Cypher short isoform deficient mice, which were viable with no overt cardiac morphology and signaling abnormalities. These results reveal distinct functional roles for Cypher isoforms in the heart as well as shed light into the molecular mechanisms underlying dilated cardiomyopathy.

scholarly journals Deficiency of the Tetraspanin CD63 Associated with Kidney Pathology but Normal Lysosomal Function

2008 ◽  
Vol 29 (4) ◽  
pp. 1083-1094 ◽  
Author(s):  
Jenny Schröder ◽  
Renate Lüllmann-Rauch ◽  
Nina Himmerkus ◽  
Irina Pleines ◽  
Bernhard Nieswandt ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Collecting Duct ◽  
Urine Osmolality ◽  
Urinary Flow ◽  
Late Endosomes ◽  
Fecal Water ◽  
Main Component ◽  
Deficient Mice ◽  
Tetraspanin Cd63

ABSTRACT CD63 is a member of the tetraspanin superfamily that constitutes a main component of the lysosomal membrane. In mice, two CD63 gene loci are present, with only one of these two being functional. We generated and analyzed mice deficient for active CD63. Disruption of CD63 results in a complete loss of CD63 protein expression. Despite its abundance in late endosomes/lysosomes, the lack of CD63 does not cause obvious endosomal/lysosomal abnormalities. CD63 knockout mice are viable and fertile without gross morphological abnormalities in the majority of tissues. No alterations in the populations of immune cells and only minor differences in platelet function were observed. This suggests that the lack of CD63 could be successfully compensated for, most likely by other tetraspanins. However, CD63 deficiency leads to an altered water balance. CD63 knockout mice show an increased urinary flow, water intake, reduced urine osmolality, and a higher fecal water content. In principle cells of the collecting duct of CD63-deficient mice, abnormal intracellular lamellar inclusions were observed. This indicates that the sorting of apical transport proteins might be impaired in these cells. CD63 knockout mice provide an important tool for analyzing the various postulated functions of CD63 in vivo.

scholarly journals Individual Somatic H1 Subtypes Are Dispensable for Mouse Development Even in Mice Lacking the H10Replacement Subtype

2001 ◽  
Vol 21 (23) ◽  
pp. 7933-7943 ◽  
Author(s):  
Yuhong Fan ◽  
Allen Sirotkin ◽  
Robert G. Russell ◽  
Julianna Ayala ◽  
Arthur I. Skoultchi
Keyword(s):  
Knockout Mice ◽  
Knockout Mouse ◽  
Embryonic Stem ◽  
Mouse Development ◽  
Double Knockout ◽  
Linker Histones ◽  
Deficient Mice ◽  
Mouse Lines

ABSTRACT H1 linker histones are involved in facilitating the folding of chromatin into a 30-nm fiber. Mice contain eight H1 subtypes that differ in amino acid sequence and expression during development. Previous work showed that mice lacking H10, the most divergent subtype, develop normally. Examination of chromatin in H10−/− mice showed that other H1s, especially H1c, H1d, and H1e, compensate for the loss of H10 to maintain a normal H1-to-nucleosome stoichiometry, even in tissues that normally contain abundant amounts of H10 (A. M. Sirotkin et al., Proc. Natl. Acad. Sci. USA 92:6434–6438, 1995). To further investigate the in vivo role of individual mammalian H1s in development, we generated mice lacking H1c, H1d, or H1e by homologous recombination in mouse embryonic stem cells. Mice lacking any one of these H1 subtypes grew and reproduced normally and did not exhibit any obvious phenotype. To determine whether one of these H1s, in particular, was responsible for the compensation present in H10−/− mice, each of the three H1 knockout mouse lines was bred with H10 knockout mice to generate H1c/H10, H1d/H10, or H1e/H10double-knockout mice. Each of these doubly H1-deficient mice also was fertile and exhibited no anatomic or histological abnormalities. Chromatin from the three double-knockout strains showed no significant change in the ratio of total H1 to nucleosomes. These results suggest that any individual H1 subtype is dispensable for mouse development and that loss of even two subtypes is tolerated if a normal H1-to-nucleosome stoichiometry is maintained. Multiple compound H1 knockouts will probably be needed to disrupt the compensation within this multigene family.

scholarly journals Genetic Targeting of Relaxin and Insulin-Like Factor 3 Receptors in Mice

Endocrinology ◽  
2004 ◽  
Vol 145 (10) ◽  
pp. 4712-4720 ◽  
Author(s):  
Aparna A. Kamat ◽  
Shu Feng ◽  
Natalia V. Bogatcheva ◽  
Anne Truong ◽  
Colin E. Bishop ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Peptide Hormone ◽  
Vascular Bundles ◽  
Biological Processes ◽  
Wild Type ◽  
Putative Receptor ◽  
Collagen Accumulation ◽  
Genetic Targeting ◽  
Deficient Mice

Abstract Relaxin (RLN) is a small peptide hormone that affects a variety of biological processes. Rln1 knockout mice exhibit abnormal nipple development, prolonged parturition, agerelated pulmonary fibrosis, and abnormalities in the testes and prostate. We describe here RLN receptor Lgr7-deficient mice. Mutant females have grossly underdeveloped nipples and are unable to feed their progeny. Some Lgr7−/− females were unable to deliver their pups. Histological analysis of Lgr7 mutant lung tissues demonstrates increased collagen accumulation and fibrosis surrounding the bronchioles and the vascular bundles, absent in wild-type animals. However, Lgr7-deficient males do not exhibit abnormalities in the testes or prostate as seen in Rln1 knockout mice. Lgr7-deficient females with additional deletion of Lgr8 (Great), another putative receptor for RLN, are fertile and have normal-sized litters. Double mutant males have normal-sized prostate and testes, suggesting that Lgr8 does not account for differences in Rln1−/− and Lgr7−/− phenotypes. Transgenic overexpression of Insl3, the cognate ligand for Lgr8, does not rescue the mutant phenotype of Lgr7-deficient female mice indicating nonoverlapping functions of the two receptors. Our data indicate that neither Insl3 nor Lgr8 contribute to the RLN signaling pathway. We conclude that the Insl3/Lgr8 and Rln1/Lgr7 actions do not overlap in vivo.

scholarly journals The antiapoptotic protein Mcl-1 is essential for the survival of neutrophils but not macrophages

Blood ◽  
2006 ◽  
Vol 109 (4) ◽  
pp. 1620-1626 ◽  
Author(s):  
Ivan Dzhagalov ◽  
Ashley St. John ◽  
You-Wen He
Keyword(s):  
Knockout Mice ◽  
Conditional Knockout ◽  
Hematopoietic Stem ◽  
Antiapoptotic Protein ◽  
Cell Lineages ◽  
Conditional Knockout Mice ◽  
Regulated Expression ◽  
Neutrophil Survival ◽  
Deficient Mice

Abstract The antiapoptotic protein Mcl-1, a member of the Bcl-2 family, plays critical roles in promoting the survival of lymphocytes and hematopoietic stem cells. Although previous studies have implicated Mcl-1 in regulating the survival of neutrophils and macrophages, the in vivo function of Mcl-1 in these 2 cell lineages remained unclear. To address this, we have generated mice conditionally lacking Mcl-1 expression in neutrophils and macrophages. We show that Mcl-1 conditional knockout mice had a severe defect in neutrophil survival, whereas macrophage survival was normal. The granulocyte compartment in the blood, spleen, and bone marrow of Mcl-1 conditional knockout mice exhibited an approximately 2- to 3-fold higher apoptotic rate than control cells. In contrast, resting and activated macrophages from Mcl-1–deficient mice exhibited normal survival and contained up-regulated expression of Bcl-2 and Bcl-xL. These data suggest that Mcl-1 plays a nonredundant role in promoting the survival of neutrophils but not macrophages.

scholarly journals Lessons from Tau-Deficient Mice

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yazi D. Ke ◽  
Alexandra K. Suchowerska ◽  
Julia van der Hoven ◽  
Dineeka M. De Silva ◽  
Christopher W. Wu ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Mouse Strains ◽  
Motor Deficits ◽  
Transgenic Mouse Models ◽  
The Past ◽  
Number Of Publications ◽  
The Brain ◽  
Deficient Mice

Both Alzheimer's disease (AD) and frontotemporal dementia (FTD) are characterized by the deposition of hyperphosphorylated forms of the microtubule-associated protein tau in neurons and/or glia. This unifying pathology led to the umbrella term “tauopathies” for these conditions, also emphasizing the central role of tau in AD and FTD. Generation of transgenic mouse models expressing human tau in the brain has contributed to the understanding of the pathomechanistic role of tau in disease. To reveal the physiological functions of tauin vivo, several knockout mouse strains with deletion of the tau-encodingMAPTgene have been established over the past decade, using different gene targeting constructs. Surprisingly, when initially introduced tau knockout mice presented with no overt phenotype or malformations. The number of publications using tau knockout mice has recently markedly increased, and both behavioural changes and motor deficits have been identified in aged mice of certain strains. Moreover, tau knockout mice have been instrumental in identifying novel functions of tau, both in cultured neurons andin vivo. Importantly, tau knockout mice have significantly contributed to the understanding of the pathophysiological interplay between Aβand tau in AD. Here, we review the literature that involves tau knockout mice to summarize what we have learned so far from depleting tauin vivo.

scholarly journals Huntingtin phosphorylation governs BDNF homeostasis and improves the phenotype of Mecp2 knockout mice

2019 ◽  
Author(s):  
Yann Ehinger ◽  
Julie Bruyère ◽  
Nicolas Panayotis ◽  
Yah-Se Abada ◽  
Emilie Borloz ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Neurotrophic Factor ◽  
Molecular Motor ◽  
Synaptic Connectivity ◽  
Knock Out ◽  
Cellular Pathways ◽  
Deficient Mice ◽  
Stimulation Of

AbstractMutations in the X-linked MECP2 gene are responsible for Rett syndrome (RTT), a severe neurological disorder for which there is no treatment. Several studies have linked the loss of MeCP2 function to alterations of brain-derived neurotrophic factor (BDNF) levels, but non-specific overexpression of BDNF only partially improves the phenotype of Mecp2-deficient mice. We and others have previously shown that huntingtin (HTT) scaffolds molecular motor complexes, transports BDNF-containing vesicles, and is under-expressed in Mecp2 knock-out brains. Here we demonstrate that promoting HTT phosphorylation at Ser421, either by a phospho-mimetic mutation or inhibition of the phosphatase calcineurin, restores endogenous BDNF axonal transport in vitro in the corticostriatal pathway, increases striatal BDNF availability and synaptic connectivity in vivo, and improves the phenotype and the survival of Mecp2 knockout mice—even though treatments were initiated only after the mice had already developed symptoms. Stimulation of endogenous cellular pathways may thus be a promising approach for the treatment of RTT patients.

scholarly journals Elimination of Protein Kinase MK5/PRAK Activity by Targeted Homologous Recombination

2003 ◽  
Vol 23 (21) ◽  
pp. 7732-7741 ◽  
Author(s):  
Yu Shi ◽  
Alexey Kotlyarov ◽  
Kathrin Laaß ◽  
Achim D. Gruber ◽  
Elke Butt ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Homologous Recombination ◽  
P38 Mapk ◽  
Knockout Mice ◽  
Endotoxic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Deficient Mice

ABSTRACT MK5 (mitogen-activated protein kinase [MAPK]-activated protein kinase 5), also designated PRAK (p38-regulated and -activated kinase), was deleted from mice by homologous recombination. Although no MK5 full-length protein and kinase activity was detected in the MK5 knockout mice, the animals were viable and fertile and did not display abnormalities in tissue morphology or behavior. In addition, these mice did not show increased resistance to endotoxic shock or decreased lipopolysaccharide-induced cytokine production. Hence, MK5 deletion resulted in a phenotype very different from the complex inflammation-impaired phenotype of mice deficient in MK2, although MK2 and MK5 exhibit evolutional, structural, and apparent extensive functional similarities. To explain this discrepancy, we used wild-type cells and embryonic fibroblasts from both MK2 and MK5 knockout mice as controls to reexamine the mechanism of activation, the interaction with endogenous p38 MAPK, and the substrate specificity of both enzymes. In contrast to MK2, which shows interaction with and chaperoning properties for p38 MAPK and which is activated by extracellular stresses such as arsenite or sorbitol treatment, endogenous MK5 did not show these properties. Furthermore, endogenous MK5 is not able to phosphorylate Hsp27 in vitro and in vivo. We conclude that the differences between the phenotypes of MK5- and MK2-deficient mice result from clearly different functional properties of both enzymes.

Sign in / Sign up

Export Citation Format

Share Document