scholarly journals Placenta Defects and Embryonic Lethality Resulting from Disruption of Mouse Hydroxysteroid (17-β) Dehydrogenase 2 Gene

2008 ◽  
Vol 22 (3) ◽  
pp. 665-675 ◽  
Author(s):  
Pia Rantakari ◽  
Leena Strauss ◽  
Riku Kiviranta ◽  
Heidi Lagerbohm ◽  
Jenni Paviala ◽  
...  
Keyword(s):  
Embryonic Stem ◽  
Basal Layer ◽  
Embryonic Lethality ◽  
Cellular Density ◽  
Targeted Gene Disruption ◽  
Structural Abnormalities ◽  
The Brain

Abstract Hydroxysteroid (17-β) dehydrogenase 2 (HSD17B2) is a member of aldo-keto reductase superfamily, known to catalyze the inactivation of 17β-hydroxysteroids to less active 17-keto forms and catalyze the conversion of 20α-hydroxyprogesterone to progesterone in vitro. To examine the role of HSD17B2 in vivo, we generated mice deficient in Hsd17b2 [HSD17B2 knockout (KO)] by a targeted gene disruption in embryonic stem cells. From the homozygous mice carrying the disrupted Hsd17b2, 70% showed embryonic lethality appearing at the age of embryonic d 11.5 onward. The embryonic lethality was associated with reduced placental size measured at embryonic d 17.5. The HSD17B2KO mice placentas presented with structural abnormalities in all three major layers: the decidua, spongiotrophoblast, and labyrinth. Most notable was the disruption of the spongiotrophoblast and labyrinthine layers, together with liquid-filled cysts in the junctional region and the basal layer. Treatments with an antiestrogen or progesterone did not rescue the embryonic lethality or the placenta defect in the homozygous mice. In hybrid background used, 24% of HSD17B2KO mice survived through the fetal period but were born growth retarded and displayed a phenotype in the brain with enlargement of ventricles, abnormal laminar organization, and increased cellular density in the cortex. Furthermore, the HSD17B2KO mice had unilateral renal degeneration, the affected kidney frequently appearing as a fluid-filled sac. Our results provide evidence for a role for HSD17B2 enzyme in the cellular organization of the mouse placenta.

The use of siRNA as a pharmacological tool to assess a role for the transcription factor NF-IL6 in the brain under in vitro and in vivo conditions during LPS-induced inflammatory stimulation

2017 ◽  
Vol 28 (6) ◽  
Author(s):  
Jelena Damm ◽  
Joachim Roth ◽  
Rüdiger Gerstberger ◽  
Christoph Rummel
Keyword(s):  
Transcription Factor ◽  
Brain Cells ◽  
Nuclear Factor ◽  
Si Rna ◽  
The Brain ◽  
Deficient Mice ◽  
Transcription Factor Nuclear Factor

AbstractBackground:Studies with NF-IL6-deficient mice indicate that this transcription factor plays a dual role during systemic inflammation with pro- and anti-inflammatory capacities. Here, we aimed to characterize the role of NF-IL6 specifically within the brain.Methods:In this study, we tested the capacity of short interfering (si) RNA to silence the inflammatory transcription factor nuclear factor-interleukin 6 (NF-IL6) in brain cells underResults:In cells of a mixed neuronal and glial primary culture from the ratConclusions:This approach was, thus, not suitable to characterize the role NF-IL6 in the brain

scholarly journals DR5 Knockout Mice Are Compromised in Radiation-Induced Apoptosis

2005 ◽  
Vol 25 (5) ◽  
pp. 2000-2013 ◽  
Author(s):  
Niklas Finnberg ◽  
Joshua J. Gruber ◽  
Peiwen Fei ◽  
Dorothea Rudolph ◽  
Anka Bric ◽  
...  
Keyword(s):  
Cell Death ◽  
Null Mouse ◽  
Organ Specific ◽  
Radiation Induced ◽  
Induced Apoptosis ◽  
The Brain ◽  
Necrosis Factor

ABSTRACT DR5 (also called TRAIL receptor 2 and KILLER) is an apoptosis-inducing membrane receptor for tumor necrosis factor-related apoptosis-inducing ligand (also called TRAIL and Apo2 ligand). DR5 is a transcriptional target of p53, and its overexpression induces cell death in vitro. However, the in vivo biology of DR5 has remained largely unexplored. To better understand the role of DR5 in development and in adult tissues, we have created a knockout mouse lacking DR5. This mouse is viable and develops normally with the exception of having an enlarged thymus. We show that DR5 is not expressed in developing embryos but is present in the decidua and chorion early in development. DR5-null mouse embryo fibroblasts expressing E1A are resistant to treatment with TRAIL, suggesting that DR5 may be the primary proapoptotic receptor for TRAIL in the mouse. When exposed to ionizing radiation, DR5-null tissues exhibit reduced amounts of apoptosis compared to wild-type thymus, spleen, Peyer's patches, and the white matter of the brain. In the ileum, colon, and stomach, DR5 deficiency was associated with a subtle phenotype of radiation-induced cell death. These results indicate that DR5 has a limited role during embryogenesis and early stages of development but plays an organ-specific role in the response to DNA-damaging stimuli.

Embryo biotechnology in the dog: a review

2010 ◽  
Vol 22 (7) ◽  
pp. 1049 ◽  
Author(s):  
Sylvie Chastant-Maillard ◽  
Martine Chebrout ◽  
Sandra Thoumire ◽  
Marie Saint-Dizier ◽  
Marc Chodkiewicz ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Embryonic Stem ◽  
Reproductive Technologies ◽  
Reproductive Physiology ◽  
Biological Models ◽  
The Past ◽  
Fertilisation Rate

Canine embryos are a scarce biological material because of difficulties in collecting in vivo-produced embryos and the inability, to date, to produce canine embryos in vitro. The procedure for the transfer of in vivo-produced embryos has not been developed adequately, with only six attempts reported in the literature that have resulted in the birth of 45 puppies. In vitro, the fertilisation rate is particularly low (∼10%) and the incidence of polyspermy particularly high. So far, no puppy has been obtained from an in vitro-produced embryo. In contrast, cloning of somatic cells has been used successfully over the past 4 years, with the birth of 41 puppies reported in the literature, a yield that is comparable to that for other mammalian species. Over the same period, canine embryonic stem sells and transgenic cloned dogs have been obtained. Thus, the latest reproductive technologies are further advanced than in vitro embryo production. The lack of fundamental studies on the specific features of reproductive physiology and developmental biology in the canine is regrettable in view of the increasing role of dogs in our society and of the current demand for new biological models in biomedical technology.

scholarly journals The Two Faces of Ascorbate: Prooxidant Activity and Radio-Sensitisation

2021 ◽  
Author(s):  
◽  
Georgia Carson
Keyword(s):  
Dna Damage ◽  
Alternative Therapy ◽  
High Dose ◽  
Intravenous Injections ◽  
Unique Nature ◽  
Therapy Option ◽  
The Brain

<p>Although not recommended by mainstream oncologists, intravenous injections of pharmacological ascorbate are currently an alternative therapy option for cancer patients. Research has not yet determined whether high-dose ascorbate interacts favourably with radiation therapy to increase DNA damage, and therefore cell death in cancer. Some studies suggest that ascorbate can act as a prooxidant and increase the cytotoxic effect of irradiation in vitro. Glioblastoma multiforme (GBM) is a primary brain astrocytoma that is highly therapy resistant, so patients would be advantaged if ascorbate radiosensitised their cancer.  In this investigation, flow cytometry and single cell gel electrophoresis (comet tail assay) were used to measure three indicators of DNA damage in GBM cells in response to ascorbate and irradiation, and were contrasted with immunofluorescence-revealed DNA damage from an intracranial mouse model of GBM.   The pro-oxidant, radiosensitisation role of ascorbate was confirmed, as measured by H2AX, 8OHdG, and DSBs in vitro. With all three of these markers of DNA damage, combinations of irradiation and ascorbate had increased damage compared with individual treatments. However preliminary in vivo evidence indicates that increased DNA damage did not occur in an animal model of GBM, and in fact ascorbate may protect from DNA damage in an in vivo context.  These findings complement previous results from our lab, and serve to fill in gaps in knowledge specifically around the DNA damaging effects of ascorbate. The unique nature of the brain environment, as enclosed by the blood brain barrier, prevents translation of data from other non-brain cancer studies, as such, this investigation also contributes to the exploration of a much needed avenue of research. Considering the context of ascorbate treatment as a potentially harmful currently used adjuvant, it is imperative to confirm or disprove its efficacy in a clinically relevant environment.</p>

scholarly journals Extracellular Matrix and Integrins in Embryonic Stem Cell Differentiation

2015 ◽  
Vol 8s2 ◽  
pp. BCI.S30377 ◽  
Author(s):  
Han Wang ◽  
Xie Luo ◽  
Jake Leighton
Keyword(s):  
Extracellular Matrix ◽  
Pancreatic Beta Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
In Vitro Differentiation ◽  
Integrin Receptors

Embryonic stem cells (ESCs) are pluripotent cells with great therapeutic potentials. The in vitro differentiation of ESC was designed by recapitulating embryogenesis. Significant progress has been made to improve the in vitro differentiation protocols by toning soluble maintenance factors. However, more robust methods for lineage-specific differentiation and maturation are still under development. Considering the complexity of in vivo embryogenesis environment, extracellular matrix (ECM) cues should be considered besides growth factor cues. ECM proteins bind to cells and act as ligands of integrin receptors on cell surfaces. Here, we summarize the role of the ECM and integrins in the formation of three germ layer progenies. Various ECM–integrin interactions were found, facilitating differentiation toward definitive endoderm, hepatocyte-like cells, pancreatic beta cells, early mesodermal progenitors, cardiomyocytes, neuroectoderm lineages, and epidermal cells, such as keratinocytes and melanocytes. In the future, ECM combinations for the optimal ESC differentiation environment will require substantial study.

Abstract P482: Elucidating And Characterizing The Molecular Mechanistic Role Of Phospholamban L39 Stop In The Pathophysiology Of Cardiomyopathy Using Patient-derived Human Induced Pluripotent Stem Cells And Humanized Knock-in Mouse Model Systems

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Anichavezhi Devendran ◽  
Rasheed Bailey ◽  
Sumanta Kar ◽  
Francesca Stillitano ◽  
Irene Turnbull ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mouse Model ◽  
Mononuclear Cells ◽  
Embryonic Stem ◽  
Model Systems ◽  
Patient Specific ◽  
Induced Pluripotent

Background: Heart failure (HF) is a complex clinical condition associated with substantial morbidity and mortality worldwide. The contractile dysfunction and arrhythmogenesis related to HF has been linked to the remodelling of calcium (Ca ++ ) handling. Phospholamban (PLN) has emerged as a key regulator of intracellular Ca ++ concentration. Of the PLN mutations, L39X is intriguing as it has not been fully characterized. This mutation is believed to be functionally equivalent to PLN null (KO) but contrary to PLN KO mice, L39X carriers develop a lethal cardiomyopathy (CMP). Our study aims at using induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) from homozygous L39X carriers to elucidate the role of L39X in human pathophysiology. Our plan also involves the characterization of humanized L39X knock-in mice (KM), which we hypothesize will develop a CMP from mis-localization of PLN and disruption of Ca ++ signalling. Methodology and Results: Mononuclear cells from Hom L39X carriers were obtained to generate 11 integration-free patient-specific iPSC clones. The iPSC-CMs were derived using established protocols. Compared to the WT iPSC-CMs, the Hom L39X derived-CMs PLN had an abnormal cytoplasmic distribution and formed intracellular aggregates, with the loss of perinuclear localization. There was also a 70% and 50% reduction of mRNA and protein expression of PLN respectively in L39X compared to WT iPSC-CMs. These findings indicated that L39X PLN is both under-expressed and mis-localized within the cell. To validate this observation in-vivo, we genetically modified FVB mice to harbour the human L39X. Following electroporation, positively transfected mouse embryonic stem cells were injected into host blastocysts to make humanized KM that were subsequently used to generate either a protamine-Cre (endogenous PLN driven expression) or a cardiac TNT mouse (i.e., CMP specific). Conclusion: Our data confirm an abnormal intracellular distribution of PLN, with the loss of perinuclear accumulation and mis-localization, suggestive of ineffective targeting to or retention of L39X. The mouse model will be critically important to validate the in-vitro observations and provides an ideal platform for future studies centred on the development of novel therapeutic strategies including virally delivered CRISPR/Cas9 for in-vivo gene editing and testing of biochemical signalling pathways.

scholarly journals Exaggerated inflammation, impaired host defense, and neuropathology in progranulin-deficient mice

2009 ◽  
Vol 207 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Fangfang Yin ◽  
Rebecca Banerjee ◽  
Bobby Thomas ◽  
Ping Zhou ◽  
Liping Qian ◽  
...  
Keyword(s):  
Host Defense ◽  
Hippocampal Slices ◽  
Interleukin 10 ◽  
Biological Processes ◽  
Listeria Monocytogenes Infection ◽  
The Brain ◽  
Deficient Mice

Progranulin (PGRN) is a widely expressed protein involved in diverse biological processes. Haploinsufficiency of PGRN in the human causes tau-negative, ubiquitin-positive frontotemporal dementia (FTD). However, the mechanisms are unknown. To explore the role of PGRN in vivo, we generated PGRN-deficient mice. Macrophages from these mice released less interleukin-10 and more inflammatory cytokines than wild type (WT) when exposed to bacterial lipopolysaccharide. PGRN-deficient mice failed to clear Listeria monocytogenes infection as quickly as WT and allowed bacteria to proliferate in the brain, with correspondingly greater inflammation than in WT. PGRN-deficient macrophages and microglia were cytotoxic to hippocampal cells in vitro, and PGRN-deficient hippocampal slices were hypersusceptible to deprivation of oxygen and glucose. With age, brains of PGRN-deficient mice displayed greater activation of microglia and astrocytes than WT, and their hippocampal and thalamic neurons accumulated cytosolic phosphorylated transactivation response element DNA binding protein–43. Thus, PGRN is a key regulator of inflammation and plays critical roles in both host defense and neuronal integrity. FTD associated with PGRN insufficiency may result from many years of reduced neutrotrophic support together with cumulative damage in association with dysregulated inflammation.

scholarly journals The effects of 6 hours of hypoxia on protein synthesis in rat tissues in vivo and in vitro

1985 ◽  
Vol 228 (1) ◽  
pp. 179-185 ◽  
Author(s):  
V R Preedy ◽  
D M Smith ◽  
P H Sugden
Keyword(s):  
Protein Synthesis ◽  
Gastric Emptying ◽  
Skeletal Muscles ◽  
Rat Tissues ◽  
Tissue Nitrogen ◽  
The Brain ◽  
H Protein

Rates of protein synthesis were measured in vivo in several tissues (heart, skeletal muscles, liver, tibia, skin, brain, kidney, lung) of fed rats exposed to O2/N2 (1:9) for 6 h starting at 08:00-11:00 h. Protein synthesis rates were depressed by 15-35% compared with normoxic controls in all of the tissues studied. The decreases were greatest in the brain and the skin. Although hypoxia inhibited gastric emptying, its effects on protein synthesis could probably not be attributed to its induction of a starved state, because protein-synthesis rates in brain and skin were not decreased by a 15-18 h period of starvation initiated at 23:00 h. Furthermore, we showed that protein synthesis was inhibited by hypoxia in the rat heart perfused in vitro, suggesting a direct effect. The role of hypoxia in perturbing tissue nitrogen balance in various physiological and pathological states is discussed.

scholarly journals Hypoxia as a Driving Force of Pluripotent Stem Cell Reprogramming and Differentiation to Endothelial Cells

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1614
Author(s):  
Paulina Podkalicka ◽  
Jacek Stępniewski ◽  
Olga Mucha ◽  
Neli Kachamakova-Trojanowska ◽  
Józef Dulak ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Disease Modeling ◽  
Embryonic Stem ◽  
Hypoxic Conditions ◽  
Vascular Structures ◽  
Induced Pluripotent

Inadequate supply of oxygen (O2) is a hallmark of many diseases, in particular those related to the cardiovascular system. On the other hand, tissue hypoxia is an important factor regulating (normal) embryogenesis and differentiation of stem cells at the early stages of embryonic development. In culture, hypoxic conditions may facilitate the derivation of embryonic stem cells (ESCs) and the generation of induced pluripotent stem cells (iPSCs), which may serve as a valuable tool for disease modeling. Endothelial cells (ECs), multifunctional components of vascular structures, may be obtained from iPSCs and subsequently used in various (hypoxia-related) disease models to investigate vascular dysfunctions. Although iPSC-ECs demonstrated functionality in vitro and in vivo, ongoing studies are conducted to increase the efficiency of differentiation and to establish the most productive protocols for the application of patient-derived cells in clinics. In this review, we highlight recent discoveries on the role of hypoxia in the derivation of ESCs and the generation of iPSCs. We also summarize the existing protocols of hypoxia-driven differentiation of iPSCs toward ECs and discuss their possible applications in disease modeling and treatment of hypoxia-related disorders.

scholarly journals Elucidating the role of leptin in systemic inflammation: a study targeting physiological leptin levels in rats and their macrophages

2017 ◽  
Vol 313 (5) ◽  
pp. R572-R582 ◽  
Author(s):  
Elizabeth A. Flatow ◽  
Evilin N. Komegae ◽  
Monique T. Fonseca ◽  
Camila F. Brito ◽  
Florin M. Musteata ◽  
...  
Keyword(s):  
Food Deprivation ◽  
Systemic Inflammation ◽  
Peritoneal Macrophages ◽  
Tnf Α ◽  
Macrophage Subpopulations ◽  
Limited Food ◽  
The Brain

To elucidate the role of leptin in acute systemic inflammation, we investigated how its infusion at low, physiologically relevant doses affects the responses to bacterial lipopolysaccharide (LPS) in rats subjected to 24 h of food deprivation. Leptin was infused subcutaneously (0–20 μg·kg−1·h−1) or intracerebroventricularly (0–1 μg·kg−1·h−1). Using hypothermia and hypotension as biomarkers of systemic inflammation, we identified the phase extending from 90 to 240 min post-LPS as the most susceptible to modulation by leptin. In this phase, leptin suppressed the rise in plasma TNF-α and accelerated the recoveries from hypothermia and hypotension. Suppression of TNF-α was not accompanied by changes in other cytokines or prostaglandins. Leptin suppressed TNF-α when infused peripherally but not when infused into the brain. Importantly, the leptin dose that suppressed TNF-α corresponded to the lowest dose that limited food consumption; this dose elevated plasma leptin within the physiological range (to 5.9 ng/ml). We then conducted in vitro experiments to investigate whether an action of leptin on macrophages could parallel our in vivo observations. The results revealed that, when sensitized by food deprivation, LPS-stimulated peritoneal macrophages can be inhibited by leptin at concentrations that are lower than those reported to promote cytokine release. It is concluded that physiological levels of leptin do not exert a proinflammatory effect but rather an anti-inflammatory effect involving selective suppression of TNF-α via an action outside the brain. The mechanism of this effect might involve a previously unrecognized, suppressive action of leptin on macrophage subpopulations sensitized by food deprivation, but future studies are warranted.

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