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

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.

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

Journal of Fungi ◽

10.3390/jof7060439 ◽

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.

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Set1 Targets Genes with Essential Identity and Tumor-Suppressing Functions in Planarian Stem Cells

Genes ◽

10.3390/genes12081182 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1182

Author(s):

Prince Verma ◽

Court K. M. Waterbury ◽

Elizabeth M. Duncan

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Mammalian Cells ◽

Cell Function ◽

Genotoxic Stress ◽

Specific Gene ◽

Cell Identity ◽

Chromatin Signature ◽

Lysine Methyltransferase

Tumor suppressor genes (TSGs) are essential for normal cellular function in multicellular organisms, but many TSGs and tumor-suppressing mechanisms remain unknown. Planarian flatworms exhibit particularly robust tumor suppression, yet the specific mechanisms underlying this trait remain unclear. Here, we analyze histone H3 lysine 4 trimethylation (H3K4me3) signal across the planarian genome to determine if the broad H3K4me3 chromatin signature that marks essential cell identity genes and TSGs in mammalian cells is conserved in this valuable model of in vivo stem cell function. We find that this signature is indeed conserved on the planarian genome and that the lysine methyltransferase Set1 is largely responsible for creating it at both cell identity and putative TSG loci. In addition, we show that depletion of set1 in planarians induces stem cell phenotypes that suggest loss of TSG function, including hyperproliferation and an abnormal DNA damage response (DDR). Importantly, this work establishes that Set1 targets specific gene loci in planarian stem cells and marks them with a conserved chromatin signature. Moreover, our data strongly suggest that Set1 activity at these genes has important functional consequences both during normal homeostasis and in response to genotoxic stress.

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TNFR25 Expression on CD4+CD25+ T Cells: Down Modulation of Regulatory Activity.

Blood ◽

10.1182/blood.v108.11.3165.3165 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3165-3165

Author(s):

Vadim Deyev ◽

Melinda Roskos ◽

Robert B. Levy ◽

Eckhard R. Podack

Keyword(s):

T Cells ◽

Cell Function ◽

Ex Vivo ◽

Cell Activity ◽

Treg Cells ◽

Regulatory Activity ◽

T Regulatory Cell ◽

Tnf Receptor Family ◽

Receptor Family

Abstract TNFR25 (“DR3”) is a member of the TNF receptor family that is expressed by activated CD4+ and CD8+ T cells. To determine if activated CD4+CD25+ T cells also expressed this TNFR family molecule, B6 CD4+CD25+ T cells were stimulated with anti-CD3/CD28 coated beads (kind gift of Dr. B. Blazar, U. Minn.) and expanded for 3–4 days. TNFR25 expression was readily detected on CD4+CD25+ FoxP3+ T cells. Since other members of the TNF receptor family (GITR, OX40, 4–1BB) are known to influence T regulatory cell function, we investigated whether TNFR25 signaling can regulate CD4+CD25+ T cell activity. TNFR25 triggering in B6-wt T regulatory CD4+CD25+ cells with the recombinant TNFR25 ligand TL1A or agonistic anti-TNFR25 antibody (4C12) resulted in reduction of their ability to suppress anti-CD3 induced ex-vivo proliferation of CD4+CD25− cells. 4C12 mediated TNFR25 signaling also reduced B6-wt Treg mediated inhibition of peptide induced proliferation of OVA-specific B6 CD8+ (OT-I) cells. To further investigate a role for TNFR25 in Treg cell regulation, TNFR25 (full length) transgenic mice were generated and bred onto the BL/6 background. CD4+CD25+ cells from these TNFR25 tg mice were found to possess diminished T regulatory activity in vitro as determined by their diminished inability to regulate proliferation by B6-wt CD4+ and OT-I CD8+ T cells. To assess their in vivo regulatory activity, B6-wt and B6 TNFR25 tg Treg cells were examined for their ability to inhibit graft vs. host disease (GVHD) following allogeneic MHC class I/II mismatched BMT. In contrast to B6-wt Treg cells, TNFR25 tg Treg cells exhibited significantly diminished ability to regulate the onset of GVHD in vivo as assessed by weight loss and clinical symptoms. Using agonistic antibody, stimulation of TNFR25 on transgenic Treg cells was also found to effectively remove the ex-vivo regulatory activity expressed by this population. To exclude any possible direct co-stimulatory effects of 4C12 antibody on the responding proliferating cells, CD4+CD25−T cells from TNFR25 dominant negative transgenic mice were employed. 4C12 mab again abolished Treg cell inhibitory activity. The effect of TNFR25 agonists on T reg cell activity in vivo is being further investigated in both mouse models of GVHD and IBD diseases. Initial observations administering 4C12 post-allogeneic BMT together with B6-wt Treg cells indicate a reduction in their ability to regulate GVHD. In total, these studies identify TNFR25 as a new potential target for augmenting CD4+ and CD8+ responses by concomitant direct co-stimulation of effecter cells and inhibition of T regulatory cell function.

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Na+/H+Antiport Is Essential for Yersinia pestis Virulence

Infection and Immunity ◽

10.1128/iai.00071-13 ◽

2013 ◽

Vol 81 (9) ◽

pp. 3163-3172 ◽

Cited By ~ 28

Author(s):

Yusuke Minato ◽

Amit Ghosh ◽

Wyatt J. Faulkner ◽

Erin J. Lind ◽

Sara Schesser Bartra ◽

...

Keyword(s):

Yersinia Pestis ◽

Drug Target ◽

Deletion Mutant ◽

Ex Vivo ◽

Ion Homeostasis ◽

Content Type ◽

Double Deletion ◽

Derivative Strain

ABSTRACTNa+/H+antiporters are ubiquitous membrane proteins that play a central role in the ion homeostasis of cells. In this study, we examined the possible role of Na+/H+antiport inYersinia pestisvirulence and found thatY. pestisstrains lacking the major Na+/H+antiporters, NhaA and NhaB, are completely attenuated in anin vivomodel of plague. TheY. pestisderivative strain lacking thenhaAandnhaBgenes showed markedly decreased survival in blood and blood serumex vivo. Complementation of eithernhaAornhaBintransrestored the survival of theY. pestis nhaA nhaBdouble deletion mutant in blood. ThenhaA nhaBdouble deletion mutant also showed inhibited growth in an artificial serum medium, Opti-MEM, and a rich LB-based medium with Na+levels and pH values similar to those for blood. Taken together, these data strongly suggest that intact Na+/H+antiport is indispensable for the survival ofY. pestisin the bloodstreams of infected animals and thus might be regarded as a promising noncanonical drug target for infections caused byY. pestisand possibly for those caused by other blood-borne bacterial pathogens.

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

Blood ◽

10.1182/blood-2004-02-0655 ◽

2004 ◽

Vol 104 (4) ◽

pp. 1217-1223 ◽

Cited By ~ 416

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)

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Clinical indices of in vivo biocompatibility: The role of ex vivo cell function studies and effluent markers in peritoneal dialysis patients

Kidney International ◽

10.1046/j.1523-1755.2003.08809.x ◽

2003 ◽

Vol 64 ◽

pp. S84-S93 ◽

Cited By ~ 17

Author(s):

Ruth Mackenzie ◽

Clifford J. Holmes ◽

Suzanne Jones ◽

John D. Williams ◽

Nicholas Topley

Keyword(s):

Peritoneal Dialysis ◽

Cell Function ◽

Ex Vivo ◽

Dialysis Patients ◽

Clinical Indices

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Sequential in vivo labeling of insulin secretory granule pools in INS-SNAP transgenic pigs

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2107665118 ◽

2021 ◽

Vol 118 (37) ◽

pp. e2107665118

Author(s):

Elisabeth Kemter ◽

Andreas Müller ◽

Martin Neukam ◽

Anna Ivanova ◽

Nikolai Klymiuk ◽

...

Keyword(s):

Secretory Granule ◽

Cell Function ◽

Ex Vivo ◽

Secretory Granules ◽

Pig Model ◽

Transgenic Pigs ◽

Glucose Levels ◽

Molecular Features ◽

Insulin Secretory Granule

β cells produce, store, and secrete insulin upon elevated blood glucose levels. Insulin secretion is a highly regulated process. The probability for insulin secretory granules to undergo fusion with the plasma membrane or being degraded is correlated with their age. However, the molecular features and stimuli connected to this behavior have not yet been fully understood. Furthermore, our understanding of β cell function is mostly derived from studies of ex vivo isolated islets in rodent models. To overcome this translational gap and study insulin secretory granule turnover in vivo, we have generated a transgenic pig model with the SNAP-tag fused to insulin. We demonstrate the correct targeting and processing of the tagged insulin and normal glycemic control of the pig model. Furthermore, we show specific single- and dual-color granular labeling of in vivo–labeled pig pancreas. This model may provide unprecedented insights into the in vivo insulin secretory granule behavior in an animal close to humans.

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

Molecular and Cellular Biology ◽

10.1128/mcb.25.5.1980-1988.2005 ◽

2005 ◽

Vol 25 (5) ◽

pp. 1980-1988 ◽

Cited By ~ 248

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.

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

Journal of Biological Rhythms ◽

10.1177/07487304211032385 ◽

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.

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