scholarly journals Melatonin Adjusts the Phase of Mouse Circadian Clocks in the Cornea Both Ex Vivo and In Vivo

2021 ◽  
pp. 074873042110323
Author(s):  
Alex V. Huynh ◽  
Ethan D. Buhr
Keyword(s):  
Mammalian Cells ◽  
Ex Vivo ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Environmental Cues ◽  
Dark Cycle ◽  
Environmental Light ◽  
Advanced Phase ◽  
Different Tissues

The presence of an endogenous circadian clock within most mammalian cells is associated with the amazing observation that within a given tissue, these clocks are largely in synchrony with each other. Different tissues use a variety of systemic or environmental cues to precisely coordinate the phase of these clocks. The cornea is a unique tissue in that it is largely isolated from the direct blood supply that most tissues experience, it is transparent to visible light, and it is exposed directly to environmental light and temperature. Melatonin is a hormone that has been implicated in regulation of the cornea’s circadian clocks. Here, we analyze the ability of rhythmic melatonin to entrain corneas ex vivo, and analyze the phase of corneal circadian clocks in vivo both in light: dark cycles and in constant darkness. We find that the presence of a retina from a melatonin-proficient mouse strain, C3Sn, can photoentrain the circadian clocks of a co-cultured mouse cornea, but a retina from a melatonin-deficient strain, C57Bl/6, cannot. Furthermore, pharmacologic blockade of melatonin or use of a retina with advanced retinal degeneration, Pde6brd1, blocks the photoentraining effect. Corneal circadian clocks in vivo adopt an advanced phase in C3Sn mice compared with C57Bl/6, but the circadian clocks in the liver are unaffected. This observation is not attributable to a shorter endogenous period of the cornea or behavior between the strains. Some transcripts of circadian genes in the corneas of C3Sn mice also show an advanced phase of expression in a light: dark cycle, while the transcript of Per2 exhibits a light-dependent transient induction at the onset of darkness. We conclude that melatonin acts as a phase modifying factor in a rhythmic manner for the circadian clocks of the cornea.

scholarly journals In Silico Predicted Antifungal Peptides: In Vitro and In Vivo Anti-Candida Activity

2021 ◽  
Vol 7 (6) ◽  
pp. 439
Author(s):  
Tecla Ciociola ◽  
Walter Magliani ◽  
Tiziano De Simone ◽  
Thelma A. Pertinhez ◽  
Stefania Conti ◽  
...  
Keyword(s):  
In Silico ◽  
Mammalian Cells ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Consensus Sequence ◽  
In Silico Analysis ◽  
Significant Activity ◽  
Synthetic Antibody

It has been previously demonstrated that synthetic antibody-derived peptides could exert a significant activity in vitro, ex vivo, and/or in vivo against microorganisms and viruses, as well as immunomodulatory effects through the activation of immune cells. Based on the sequence of previously described antibody-derived peptides with recognized antifungal activity, an in silico analysis was conducted to identify novel antifungal candidates. The present study analyzed the candidacidal and structural properties of in silico designed peptides (ISDPs) derived by amino acid substitutions of the parent peptide KKVTMTCSAS. ISDPs proved to be more active in vitro than the parent peptide and all proved to be therapeutic in Galleria mellonella candidal infection, without showing toxic effects on mammalian cells. ISDPs were studied by circular dichroism spectroscopy, demonstrating different structural organization. These results allowed to validate a consensus sequence for the parent peptide KKVTMTCSAS that may be useful in the development of novel antimicrobial molecules.

Efficient magnetic cell labeling with protamine sulfate complexed to ferumoxides for cellular MRI

Blood ◽  
2004 ◽  
Vol 104 (4) ◽  
pp. 1217-1223 ◽  
Author(s):  
Ali S. Arbab ◽  
Gene T. Yocum ◽  
Heather Kalish ◽  
Elaine K. Jordan ◽  
Stasia A. Anderson ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mammalian Cells ◽  
Ex Vivo ◽  
Human Mesenchymal Stem Cells ◽  
Superparamagnetic Iron Oxide ◽  
Protamine Sulfate ◽  
Mri Contrast Agent ◽  
Cell Labeling ◽  
Cellular Iron

AbstractRecently, there have been several reports using various superparamagnetic iron oxide (SPIO) nanoparticles to label mammalian cells for monitoring their temporal and spatial migration in vivo by magnetic resonance imaging (MRI). The purpose of this study was to evaluate the efficiency and toxicity of labeling cells using 2 commercially available Food and Drug Administration (FDA)-approved agents, ferumoxides, a suspension of dextran-coated SPIO used as an MRI contrast agent, and protamine sulfate, conventionally used to reverse heparin anticoagulation but also used ex vivo as a cationic transfection agent. After labeling of human mesenchymal stem cells (MSCs) and hematopoietic (CD34+) stem cells and other mammalian cells with ferumoxides-protamine sulfate complexes (FE-Pro), cellular toxicity, functional capacity, and quantitative cellular iron incorporation were determined. FE-Pro-labeled cells demonstrated no short- or long-term toxicity, changes in differentiation capacity of the stem cells, or changes in phenotype when compared with unlabeled cells. Efficient labeling with FE-Pro was observed with iron content per cell varying between 2.01 ± 0.1 pg for CD34+ cells and 10.94 ± 1.86 pg for MSCs with 100% of cells labeled. Cell labeling using these agents should facilitate the translation of this method to clinical trials for evaluation of trafficking of infused or transplanted cells by MRI. (Blood. 2004;104:1217-1223)

scholarly journals Differentiating external zeitgeber impact on peripheral circadian clock resetting

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Isabel Heyde ◽  
Henrik Oster
Keyword(s):  
Energy Metabolism ◽  
Metabolic Disorders ◽  
Circadian Clocks ◽  
Metabolic Homeostasis ◽  
Experimental Paradigm ◽  
Dark Cycle ◽  
Clock System ◽  
Specific Tissue ◽  
Hierarchical Manner

AbstractCircadian clocks regulate physiological functions, including energy metabolism, along the 24-hour day cycle. The mammalian clock system is organized in a hierarchical manner with a coordinating pacemaker residing in the hypothalamic suprachiasmatic nucleus (SCN). The SCN clock is reset primarily by the external light-dark cycle while other zeitgebers such as the timing of food intake are potent synchronizers of many peripheral tissue clocks. Under conflicting zeitgeber conditions, e.g. during shift work, phase synchrony across the clock network is disrupted promoting the development of metabolic disorders. We established a zeitgeber desynchrony (ZD) paradigm to quantify the differential contributions of the two main zeitgebers, light and food, to the resetting of specific tissue clocks and the effect on metabolic homeostasis in mice. Under 28-hour light-dark and 24-hour feeding-fasting conditions SCN and peripheral clock, as well as activity and hormonal rhythms showed specific periodicities aligning in-between those of the two zeitgebers. During ZD, metabolic homeostasis was cyclic with mice gaining weight under synchronous and losing weight under conflicting zeitgeber conditions. In summary, our study establishes an experimental paradigm to compare zeitgeber input in vivo and study the physiological consequences of chronodisruption.

scholarly journals Cytoplasmic Thioredoxin Reductase Is Essential for Embryogenesis but Dispensable for Cardiac Development

2005 ◽  
Vol 25 (5) ◽  
pp. 1980-1988 ◽  
Author(s):  
Cemile Jakupoglu ◽  
Gerhard K. H. Przemeck ◽  
Manuela Schneider ◽  
Stéphanie G. Moreno ◽  
Nadja Mayr ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cardiac Development ◽  
Ex Vivo ◽  
Cell Communication ◽  
Thioredoxin Reductase ◽  
Early Embryonic Lethality ◽  
The Individual ◽  
Thioredoxin Reductases

ABSTRACT Two distinct thioredoxin/thioredoxin reductase systems are present in the cytosol and the mitochondria of mammalian cells. Thioredoxins (Txn), the main substrates of thioredoxin reductases (Txnrd), are involved in numerous physiological processes, including cell-cell communication, redox metabolism, proliferation, and apoptosis. To investigate the individual contribution of mitochondrial (Txnrd2) and cytoplasmic (Txnrd1) thioredoxin reductases in vivo, we generated a mouse strain with a conditionally targeted deletion of Txnrd1. We show here that the ubiquitous Cre-mediated inactivation of Txnrd1 leads to early embryonic lethality. Homozygous mutant embryos display severe growth retardation and fail to turn. In accordance with the observed growth impairment in vivo, Txnrd1-deficient embryonic fibroblasts do not proliferate in vitro. In contrast, ex vivo-cultured embryonic Txnrd1-deficient cardiomyocytes are not affected, and mice with a heart-specific inactivation of Txnrd1 develop normally and appear healthy. Our results indicate that Txnrd1 plays an essential role during embryogenesis in most developing tissues except the heart.

scholarly journals Circadian rhythms of gastrointestinal function are regulated by both central and peripheral oscillators

2012 ◽  
Vol 303 (4) ◽  
pp. G461-G473 ◽  
Author(s):  
Jaclyn N. Malloy ◽  
Jiffin K. Paulose ◽  
Ye Li ◽  
Vincent M. Cassone
Keyword(s):  
Circadian Rhythms ◽  
Ex Vivo ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Restricted Feeding ◽  
Chemical Sympathectomy ◽  
Surgical Ablation ◽  
Peripheral Oscillators ◽  
Ad Libitum ◽  
6 Hydroxydopamine

Circadian clocks are responsible for daily rhythms in a wide array of processes, including gastrointestinal (GI) function. These are vital for normal digestive rhythms and overall health. Previous studies demonstrated circadian clocks within the cells of GI tissue. The present study examines the roles played by the suprachiasmatic nuclei (SCN), master circadian pacemaker for overt circadian rhythms, and the sympathetic nervous system in regulation of circadian GI rhythms in the mouse Mus musculus . Surgical ablation of the SCN abolishes circadian locomotor, feeding, and stool output rhythms when animals are presented with food ad libitum, while restricted feeding reestablishes these rhythms temporarily. In intact mice, chemical sympathectomy with 6-hydroxydopamine has no effect on feeding and locomotor rhythmicity in light-dark cycles or constant darkness but attenuates stool weight and stool number rhythms. Again, however, restricted feeding reestablishes rhythms in locomotor activity, feeding, and stool output rhythms. Ex vivo, intestinal tissue from PER2::LUC transgenic mice expresses circadian rhythms of luciferase bioluminescence. Chemical sympathectomy has little effect on these rhythms, but timed administration of the β-adrenergic agonist isoproterenol causes a phase-dependent shift in PERIOD2 expression rhythms. Collectively, the data suggest that the SCN are required to maintain feeding, locomotor, and stool output rhythms during ad libitum conditions, acting at least in part through daily activation of sympathetic activity. Even so, this input is not necessary for entrainment to timed feeding, which may be the province of oscillators within the intestines themselves or other components of the GI system.

scholarly journals Compensatory ion transport buffers daily protein rhythms to regulate osmotic balance and cellular physiology

2020 ◽  
Author(s):  
Alessandra Stangherlin ◽  
David C. S. Wong ◽  
Silvia Barbiero ◽  
Joseph L. Watson ◽  
Aiwei Zeng ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cell Function ◽  
Ex Vivo ◽  
Ion Homeostasis ◽  
Protein Abundance ◽  
Ion Composition ◽  
Cellular Physiology ◽  
Circadian Control ◽  
Osmotic Balance

AbstractBetween 6-20% of the cellular proteome is under circadian control to tune cell function with cycles of environmental change. For cell viability, and to maintain volume within narrow limits, the osmotic pressure exerted by changes in the soluble proteome must be compensated. The mechanisms and consequences underlying compensation are not known. Here, we show in cultured mammalian cells and in vivo that compensation requires electroneutral active transport of Na+, K+, and Cl− through differential activity of SLC12A family cotransporters. In cardiomyocytes ex vivo and in vivo, compensatory ion fluxes alter their electrical activity at different times of the day. Perturbation of soluble protein abundance has commensurate effects on ion composition and cellular function across the circadian cycle. Thus, circadian regulation of the proteome impacts ion homeostasis with substantial consequences for the physiology of electrically active cells such as cardiomyocytes.

Selective nematocidal effects of essential oils from two cultivated Artemisia absinthium populations

2015 ◽  
Vol 70 (9-10) ◽  
pp. 275-280 ◽  
Author(s):  
Juan José García-Rodríguez ◽  
María-Fé Andrés ◽  
Alexandra Ibañez-Escribano ◽  
Luis F. Julio ◽  
Jesús Burillo ◽  
...  
Keyword(s):  
Essential Oils ◽  
Mammalian Cells ◽  
Trichinella Spiralis ◽  
Ex Vivo ◽  
Dose Range ◽  
Meloidogyne Javanica ◽  
Root Knot Nematode ◽  
Artemisia Absinthium ◽  
Plant Parasitic

Abstract Essential oils (EOs) obtained from two crops and populations of thujone-free cultivated Artemisia absinthium were tested against two nematode models, the mammalian parasite Trichinella spiralis, and the plant parasitic root knot nematode Meloidogyne javanica. The EOs were characterized by the presence of (Z)-epoxyocimene and chrysanthenol as major components and showed time and population dependent quantitative and qualitative variations in composition. The EOs showed a strong ex vivo activity against the L1 larvae of the nematode Trichinella spiralis with a reduction of infectivity between 72 and 100% at a dose range of 0.5–1 mg/ml in absence of cytotoxicity against mammalian cells. Moreover, the in vivo activity of the EO against T. spiralis showed a 66% reduction of intestinal adults. However, these oils were not effective against M. javanica.

scholarly journals Bone marrow transplantation for chronic myeloid leukemia with volunteer unrelated donors using ex vivo or in vivo T-cell depletion: major prognostic impact of HLA class I identity between donor and recipient

Blood ◽  
1995 ◽  
Vol 86 (9) ◽  
pp. 3590-3597 ◽  
Author(s):  
A Spencer ◽  
RM Szydlo ◽  
PA Brookes ◽  
E Kaminski ◽  
S Rule ◽  
...  
Keyword(s):  
T Cell ◽  
Ex Vivo ◽  
Chronic Phase ◽  
High Dose Chemotherapy ◽  
Cell Depletion ◽  
Class I ◽  
High Dose ◽  
T Cell Depletion ◽  
Advanced Phase

Between August 1985 and July 1994, we performed 115 volunteer unrelated donor (VUD) bone marrow transplants (BMT) for first chronic phase (n = 86) or advanced phase (n = 29) chronic myeloid leukemia (CML). Standard serologic HLA typing of potential donors and recipients was supplemented with one-dimensional isoelectric focusing (IEF) for class I proteins, allogenotyping for DR and DQ alleles using DNA restriction fragment length polymorphism (RFLP) analysis, and the measurement of antirecipient major histocompatibility complex (MHC) cytotoxic T- lymphocyte precursor cells in the donors' blood (CTLp assay). Recipients were conditioned for transplantation with a combination of high-dose chemotherapy and total body irradiation (n = 103) or high- dose chemotherapy alone (n = 12). Twenty eight recipients received ex vivo T-cell-depleted marrow, and 84 underwent some form of in vivo T- cell depletion. The probability of severe (grades III or IV) acute graft-versus-host disease (aGVHD) was 24%, and that of extensive chronic graft-versus-host disease (cGVHD), 38%. Proportional hazards regression analysis showed an association between low frequency CTLp and a reduced incidence of severe aGVHD (relative risk [RR], 0.28; P = .0035). The probability of relapse at 3 years was 23%, with first chronic phase disease being independently associated with a lower risk of relapse (RR, 0.71; P = .01). The overall leukemia-free survival (LFS) at 3 years was 37%; the LFS for the first chronic phase and advanced phase recipients was 41% and 26%, respectively. First chronic phase disease (RR, 0.56; P = .063) and the combination of recipient cytomegalovirus (CMV) seronegativity and an IEF-matched donor (RR, 0.48; P = .011) were both associated with improved LFS. The probabilities of survival and LFS for patients under 40 years of age transplanted in first chronic phase from an IEF-matched donor were 73% and 50%, respectively. We conclude that VUD BMT is a reasonable option for patients with CML; when using ex vivo or in vivo T-cell depletion, optimal results are achieved in patients transplanted in chronic phase with marrow from donors without demonstrable class I HLA mismatch and a low CTLp frequency.

scholarly journals Differential impacts of the head onPlatynereis dumeriliiperipheral circadian rhythms

2019 ◽  
Author(s):  
Enrique Arboleda ◽  
Martin Zurl ◽  
Kristin Tessmar-Raible
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Clock Genes ◽  
Functional Model ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Dark Cycle ◽  
Peripheral Tissues ◽  
Platynereis Dumerilii ◽  
Strong Control

AbstractBackgroundThe marine bristle wormPlatynereis dumeriliiis a useful functional model system for the study of the circadian clock and its interplay with others, e.g. circalunar clocks. The focus has so far been on the worm’s head. However, behavioral and physiological cycles in other animals typically arise from the coordination of circadian clocks located in the brain and in peripheral tissues. Here we focus on peripheral circadian rhythms and clocks, revisit and expand classical circadian work on the worm’s chromatophores, investigate locomotion as read-out and include molecular analyses.ResultsWe establish that different pieces of the trunk exhibit synchronized, robust oscillations of core circadian clock genes. These circadian core clock transcripts are under strong control of the light-dark cycle, quickly losing synchronized oscillation under constant darkness, irrespective of the absence or presence of heads. Different wavelengths are differently effective in controlling the peripheral molecular synchronization. We have previously shown that locomotor activity is under circadian clock control. Here we show that upon decapitation it still follows the light-dark cycle, but does not free-run under constant darkness. We also observe the rhythmicity of pigments in the worm’s individual chromatophores, confirming that chromatophore size changes follow a circadian pattern. These size changes continue under constant darkness, but cannot be re-entrained by light upon decapitation.ConclusionsHere we provide the first basic characterization of the peripheral circadian clock ofPlatynereis dumerilii. In the absence of the head, light is essential as a major synchronization cue for peripheral molecular and locomotor circadian rhythms. Circadian changes in chromatophore size can however continue for several days in the absence of light/dark changes and the head. Thus, the dependence on the head depends on the type of peripheral rhythm studied. These data show that peripheral circadian rhythms and clocks should be considered when investigating the interactions of clocks with different period lengths, a notion likely also true for other organisms with circadian and non-circadian clocks.

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