Zinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200 µM ZG for 0-24 h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1ß protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons. Overall design: 5 treatment groups, 3 replicates/group, 1 control group, 3 groups treated with 100 µM zinc gluconate for increasing time (6, 12, and 24 h), 1 group treated with 200 µM zinc gluconate for 6 h
Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora.
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View SamplesMonoallelic expression of autosomal genes (MAE) is a widespread epigenetic phenomenon which is poorly understood, due in part to current limitations of genome-wide approaches for assessing it. Recently, we reported that a specific histone modification signature is strongly associated with MAE, and demonstrated that it can serve as a proxy of MAE in human lymphoblastoid cells (Nag et al. Elife. 2013 Dec 31;2:e01256). Here, we use murine cells to establish that this chromatin signature is conserved between mouse and human, and is associated with MAE in every tested cell type. Our analyses reveal extensive conservation in the identity of MAE genes between the two species. By applying MAE chromatin signature analysis to a large number of cell and tissue types, we show that the MAE state remains consistent during terminal cell differentiation and is predominant among cell-type specific genes, suggesting a link between MAE and specification of cell identity. Overall design: PolyA RNA purification and subsequent high-throughput sequencing were performed on two independent B-lymphoid clonal cell line, derived from 129S1/SvImJ x CAST/EiJ F1 mice and immortalized with Abelson murine leukemia virus, and on two independent fibroblast clonal cell lines, derived from 129S1/Sv x CAST/EiJ F1 and immortalized with SV40.
Chromatin Signature Identifies Monoallelic Gene Expression Across Mammalian Cell Types.
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View SamplesLung transplantation remains the only viable therapy for patients with end-stage lung disease; however, full utilization of this treatment strategy is severely compromised by the lack of donor lung availability. For example, the vast majority of donor lungs available for transplantation are obtained from brain death (BD) individuals. Unfortunately, the autonomic storm which accompanies BD often results in neurogenic pulmonary edema (NPE), thereby either producing irreversible lung injury or leading to primary graft dysfunction following lung transplantation. We previously demonstrated that sphingosine 1-phosphate (S1P), a phospholipid angiogenic factor and major barrier-enhancing agent, as well as S1P analogues serve to reduce vascular permeability and ischemia/reperfusion (I/R) lung injury in rodents via ligation of the S1P1 receptor, S1PR1. As primary lung graft dysfunction is induced by lung vascular endothelial cell barrier dysfunction, we hypothesized that SEW-2871, a S1PR1 agonist, may attenuate NPE when administered to the donor shortly after BD. Significant lung injury was observed 4h after BD in a rat BD model with ~60% increases in BAL total protein, BAL cell counts, and lung tissue W/D weight ratios. In contrast, rats receiving SEW-2871 (0.1 mg/kg) 15 minutes after the induction of BD and assessed 4h later exhibited significant lung protection (~50% reduction, p=0.01) reflected by reduced BAL total protein, BAL cytokines concentrations, BAL albumin, BAL total cell count and lung tissue wet/dry (W/D) weights ratio. Microarray analysis at 4hrs revealed a global impact of both BD and SEW on lung gene expression with differential expression of a subclass of genes enriched in immune/inflammation response pathways across the 4 experimental groups. Overall, SEW served to attenuate the BD-mediated ie gene expression upregulation. Two potentially useful biomarkers, Tnf and Ccrl2, exhibited gene dysregulation by microarray analysis, which was validated by qPCR. We conclude that SEW-2871 significantly attenuates BD-induced lung injury and may serve as a potential candidate to improve human lung donor availability and transplantation outcomes.
A sphingosine 1-phosphate 1 receptor agonist modulates brain death-induced neurogenic pulmonary injury.
Sex, Specimen part, Treatment
View SamplesCholecystokinin (CCK) is a satiety hormone produced by discrete enteroendocrine cells scattered among absorptive cells of the small intestine. CCK is released into blood following a meal; however, the mechanisms inducing hormone secretion are largely unknown. Ingested fat is the major stimulant of CCK secretion. We recently identified a novel member of the lipoprotein remnant receptor family known as immunoglobulin-like domain containing receptor 1 (ILDR1) in intestinal CCK cells and postulated that this receptor conveyed the signal for fat-stimulated CCK secretion. In the intestine, ILDR1 is expressed exclusively in CCK cells. Orogastric administration of fatty acids elevated blood levels of CCK in wild type but not ILDR1-deficient mice, although the CCK secretory response to trypsin inhibitor was retained. The uptake of fluorescently labeled lipoproteins in ILDR1-transfected CHO cells and release of CCK from isolated intestinal cells required a unique combination of fatty acid plus HDL. CCK secretion secondary to ILDR1 activation is associated with increased [Ca2+]i consistent with regulated hormone release. These findings demonstrate that ILDR1 regulates CCK release through a mechanism dependent on fatty acids and lipoproteins and that absorbed fatty acids regulate gastrointestinal hormone secretion.
Immunoglobulin-like domain containing receptor 1 mediates fat-stimulated cholecystokinin secretion.
Specimen part
View SamplesRegulatory T cells (Tregs) can suppress a wide variety of cell types, in diverse organ sites and inflammatory conditions. While Tregs possess multiple suppressive mechanisms, the number required for maximal function is unclear. Furthermore, whether any inter-relationship orcross-regulatory mechanisms exist that areused to orchestrate and control their utilization is unknown. Here we assessed the functional capacity of Tregs lacking the ability to secrete both interleukin-10 (IL-10) and IL-35, which individually are required for maximal Treg activity. Surprisingly, IL-10/IL-35-double deficient Tregswere fully functionalin vitro and in vivo. Loss of IL-10 and IL-35 was compensated for by a concurrent increase in cathepsin E (CTSE) expression, enhanced TRAIL (Tnfsf10)expression and soluble TRAIL release, rendering IL-10/IL-35-double deficient Tregsfunctionally dependent on TRAIL in vitro and in vivo. Lastly, while C57BL/6 Tregs are IL-10/IL-35-dependent, Balb/c Tregs, which express high levels of CTSE and enhanced TRAIL expression, are TRAIL-dependent.These data reveal that cross-regulatory pathways exist, which control the utilization of suppressive mechanisms,thereby providing Tregfunctional plasticity.
The plasticity of regulatory T cell function.
Specimen part
View SamplesRegulatory T cells (Treg) represent a critical immunoregulatory component of the immune system. The signals that maintain Treg stability and potentiate their function remain obscure. Here we show that the immune cell surface ligand semaphorin-4a (Sema4a)
Stability and function of regulatory T cells is maintained by a neuropilin-1-semaphorin-4a axis.
Treatment
View SamplesCTCF (CCCTC-binding factor) is a highly conserved 11-zinc finger DNA binding protein with tens of thousands of binding sites genome-wide. CTCF acts as a multifunctional regulator of transcription, having been previously associated with activator, repressor, and insulator activity. These diverse regulatory functions are crucial for preimplantation development and are implicated in the regulation of numerous lineage-specific genes. Despite playing a critical role in developmental gene regulation, the mechanisms that underlie developmental changes in CTCF recruitment and function are poorly understood. Our previous work suggested that differences in CTCF’s binding site sequence may affect the regulation of CTCF recruitment, as well as CTCF’s regulatory function. To investigate these two possibilities directly during a developmental process, changes in genome-wide CTCF binding and gene expression were characterized during in vitro differentiation of mouse embryonic stem cells. CTCF binding sites were initially separated into three classes (named LowOc, MedOc, and HighOc) based on similarity to the consensus motif. The LowOc class, with lower-similarity to the consensus motif, is more likely to show changes in binding during differentiation. These more dynamically bound sites are enriched for motifs that confer a lower in vitro affinity for CTCF, suggesting a mechanism where sites with low-binding affinity are more amenable to developmental control. Additionally, by comparing changes in CTCF binding with changes in gene expression during differentiation, we show that LowOc and HighOc sites are associated with distinct regulatory functions. In sum, these results suggest that the regulatory control of CTCF’s binding and function is dependent in part upon specific motifs within its DNA binding site. Overall design: Mouse E14 ES cells were differentiated in vitro for 4.5 days using retinoic acid. RNA-Seq was performed from cells collected before and after differentiation.
CTCF binding site sequence differences are associated with unique regulatory and functional trends during embryonic stem cell differentiation.
Specimen part, Cell line, Subject
View SamplesAML with mutated NPM1 usually carries normal karyotype (NK) but it may harbor chromosomal aberrations whose significance remains unclear. We addressed this question in 631 AML patients with mutated/cytoplasmic NPM1. An abnormal karyotype (AK) was present in 93/631 cases (14.7%), the most frequent abnormalities being +8, +4, -Y, del(9q), +21. Chromosome aberrations in NPM1-mutated AML were similar to, but occurred less frequently than additional chromosome changes found in other AML with recurrent cytogenetic abnormalities according to WHO classification. Four of the 31 NPM1-mutated AML patients karyotyped at different time points had NK at diagnosis but AK at relapse: del(9q) (n=2), t(2;11) (n=1), inv(12) (n=1).
AML with mutated NPM1 carrying a normal or aberrant karyotype show overlapping biologic, pathologic, immunophenotypic, and prognostic features.
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View SamplesMyotonic dystrophes (DM), the most common adult muscular dystrophy, are the first recognized examples of RNA-mediated diseases in which expression of mutant RNAs containing expanded CUG or CCUG repeats interfere with the splicing of other mRNAs. Using whole-genome microarrays, we found that alternative splicing of the BIN1 mRNA is altered in DM skeletal muscle tissues, resulting in the expression of an inactive form of BIN1 deprived of phosphoinositide-binding and membrane-tubulating activities. BIN1 is involved in tubular invaginations of the plasma membrane and is essential for biogenesis of the muscle T-tubules, which are specialized skeletal muscle membrane structures essential to correct excitation-contraction (E-C) coupling. Mutations in the BIN1 gene cause centronuclear myopathy (CNM) that shares some histopathological features with DM, and both diseases are characterized by muscle weakness. Consistent with a loss-of-function of BIN1, muscle T-tubules were altered in DM patients, and membrane tubulation was restored upon expression of the correct splicing form of BIN1 in DM muscle cells. By deciphering the mechanism of BIN1 splicing mis-regulation we demonstrate that the splicing regulator, MBNL1, which is sequestered by expanded CUG and CCUG in DM, binds the BIN1 pre-mRNA and regulates directly its alternative splicing. Finally, reproducing BIN1 splicing alteration in mice is sufficient to reproduce the DM features of T-tubule alterations and muscle weakness. We propose that alteration of BIN1 alternative splicing regulation leads to muscle weakness, a predominant pathological feature of DM.
Misregulated alternative splicing of BIN1 is associated with T tubule alterations and muscle weakness in myotonic dystrophy.
Specimen part
View SamplesRegulatory T cells (Tregs) are critical for maintaining self-tolerance and immune homeostasis, but their suppressive function can impede effective anti-tumor immune responses. Foxp3 is a transcription factor expressed in Tregs that is required for their function. The pathways and microenvironmental cues governing Foxp3 expression and Treg function are not completely understood. We found that Yes-associated protein (YAP), a co-activator of the Hippo pathway, is highly expressed in Tregs and bolsters Foxp3 expression and Treg function in vitro and in vivo. To assess how YAP influences patterns of gene expression in Tregs, naïve CD4+ T cells and Tregs were isolated from wild type mice and CD4+ T cell lineage-restricted YAP knockout mice (YAPflox/flox, CD4-Cre+). Gene expression by naïve CD4+ T cells and their resting and stimulated Treg counterparts was analyzed by RNASeq. Our findings reveal that YAP ablation undermines expression of multiple genes involved in the TGFß/SMAD signaling pathway in Tregs including Activin. These findings suggest that YAP potentiates activity along a pro-Treg signaling axis. Overall design: The gene expression patterns in naïve T cells and nTregs from Wild type and YAP cKO (YAP flox/flox,CD4-Cre+) mice were assessed and compared using RNASeq. Sequencing was performed using a Illumina Hiseq2000.
YAP Is Essential for Treg-Mediated Suppression of Antitumor Immunity.
Specimen part, Cell line, Treatment, Subject
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