scholarly journals Naturalistic Stress Hormone Levels Drive Cumulative Epigenomic Changes along the Cellular Lifespan

2021 ◽  
Vol 22 (16) ◽  
pp. 8778
Author(s):  
Anthony S. Zannas
Keyword(s):  
Molecular Mechanisms ◽  
Cell Function ◽  
Human Fibroblasts ◽  
Stress Hormones ◽  
Stress Hormone ◽  
Cumulative Impact ◽  
Spatiotemporal Model ◽  
Genome Wide ◽  
Open Sea

Environmental stress is ubiquitous in modern societies and can exert a profound and cumulative impact on cell function and health phenotypes. This impact is thought to be in large part mediated by the action of glucocorticoid stress hormones, primarily cortisol in humans. While the underlying molecular mechanisms are unclear, epigenetics—the chemical changes that regulate genomic function without altering the genetic code—has emerged as a key link between environmental exposures and phenotypic outcomes. The present study assessed genome-wide DNA (CpG) methylation, one of the key epigenetic mechanisms, at three timepoints during prolonged (51-day) exposure of cultured human fibroblasts to naturalistic cortisol levels, which can be reached in human tissues during in vivo stress. The findings support a spatiotemporal model of profound and widespread stress hormone-driven methylomic changes that emerge at selected CpG sites, are more likely to spread to nearby located CpGs, and quantitatively accrue at open sea, glucocorticoid receptor binding, and chromatin-accessible sites. Taken together, these findings provide novel insights into how prolonged stress may impact the epigenome, with potentially important implications for stress-related phenotypes.

Abstract 12192: MBNL1 Directly Regulates the Alternative Splicing of mRNAs That Promote Myofibroblast Differentiation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jennifer Davis ◽  
Michelle Sargent ◽  
Jianjian Shi ◽  
Lei Wei ◽  
Maurice S Swanson ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Cardiac Injury ◽  
Myofibroblast Differentiation ◽  
Genome Wide ◽  
A Genome

Rationale: During the cardiac injury response fibroblasts differentiate into myofibroblasts, a cell type that enhances extracellular matrix production and facilitates ventricular remodeling. To better understand the molecular mechanisms whereby myofibroblasts are generated in the heart we performed a genome-wide screen with 18,000 cDNAs, which identified the RNA-binding protein muscleblind-like splicing regulator 1 (MBNL1), suggesting a novel association between mRNA alternative splicing and the regulation of myofibroblast differentiation. Objective: To determine the mechanism whereby MBNL1 regulates myofibroblast differentiation and the cardiac fibrotic response. Methods and Results: Confirming the results from our genome wide screen, adenoviral-mediated overexpression of MBNL1 promoted transformation of rat cardiac fibroblasts and mouse embryonic fibroblasts (MEFs) into myofibroblasts, similar to the level of conversion obtained by the profibrotic agonist transforming growth factor β (TGFβ). Antithetically, Mbnl1 -/- MEFs were refractory to TGFβ-induced myofibroblast differentiation. MBNL1 expression is induced in transforming fibroblasts in response to TGFβ and angiotensin II. These results were extended in vivo by analysis of dermal wound healing, a process dependent on myofibroblast differentiation and their proper activity. By day 6 control mice had achieved 82% skin wound closure compared with only 40% in Mbnl1 -/- mice. Moreover, Mbnl1 -/- mice had reduced survival following myocardial infarction injury due to defective fibrotic scar formation and healing. High throughput RNA sequencing (RNAseq) and RNA immunoprecipitation revealed that MBNL1 directly regulates the alternative splicing of transcripts for myofibroblast signaling factors and cytoskeletal-assembly elements. Functional analysis of these factors as mediators of MBNL1 activity is also described here. Conclusions: Collectively, our data suggest that MBNL1 coordinates myofibroblast transformation by directly mediating the alternative splicing of an array of mRNAs encoding differentiation-specific signaling transcripts, which then alter the fibroblast proteome for myofibroblast structure and function.

scholarly journals Paupar LncRNA Promotes KAP1 Dependent Chromatin Changes And Regulates Subventricular Zone Neurogenesis

2017 ◽  
Author(s):  
Ioanna Pavlaki ◽  
Farah Alammari ◽  
Bin Sun ◽  
Neil Clark ◽  
Tamara Sirey ◽  
...  
Keyword(s):  
Subventricular Zone ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Neuroblastoma Cell ◽  
Regulatory Protein ◽  
Regulatory Elements ◽  
Loss Of Function ◽  
Transcriptional Regulatory Elements ◽  
Genome Wide

ABSTRACTMany long non-coding RNAs (lncRNAs) are expressed during central nervous system (CNS) development, yet their in vivo roles and molecular mechanisms of action remain poorly understood. Paupar, a CNS expressed lncRNA, controls neuroblastoma cell growth by binding and modulating the activity of genome-wide transcriptional regulatory elements. We show here that Paupar transcript directly binds KAP1, an essential epigenetic regulatory protein, and thereby regulates the expression of shared target genes important for proliferation and neuronal differentiation. Paupar promotes KAP1 chromatin occupancy and H3K9me3 deposition at a subset of distal targets, through formation of a DNA binding ribonucleoprotein complex containing Paupar, KAP1 and the PAX6 transcription factor. Paupar-KAP1 genome-wide co-occupancy reveals a 4-fold enrichment of overlap between Paupar and KAP1 bound sequences. Furthermore, both Paupar and Kap1 loss of function in vivo accelerates lineage progression in the mouse postnatal subventricular zone (SVZ) stem cell niche and disrupts olfactory bulb neurogenesis. These observations provide important conceptual insights into the trans-acting modes of lncRNA-mediated epigenetic regulation, the mechanisms of KAP1 genomic recruitment and identify Paupar and Kap1 as regulators of SVZ neurogenesis.

scholarly journals TREM2 Limits Progression of Deficits and Spreading of Tau Pathology in Mice

2021 ◽  
Author(s):  
Astrid F. Feiten ◽  
Carol Au ◽  
Annika van Hummel ◽  
Julia van der Hoven ◽  
Yuanyuan Deng ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Association Studies ◽  
Amyloid Β ◽  
Distinct Pattern ◽  
Genome Wide Association Studies ◽  
Tau Pathology ◽  
Functional Deficits ◽  
Genome Wide ◽  
Deficient Mice

Abstract Background. Amyloid-β (Aβ) and tau form pathogenic lesions in Alzheimer’s disease (AD) brains. As ΑD clinically progresses, tau pathology propagates in a very distinct pattern between connected brain areas. The molecular mechanisms underlying this tau pathology spread remain largely unknown. Genome-wide association studies have identified polymorphisms in triggering receptor expressed on myeloid cells 2 ( TREM2 ) as genetic risk factors for AD and regulators of Aβ pathology-dependent tau propagation. Whether TREM2 contributes to neuron-to-neuron spreading of pathological tau remains unknown.Methods. Here, we crossed Trem2- deficient mice with P301S tau transgenic TAU58 mice and subjected the mice to behavioral testing and assessed neuropathology. Microglial activation states were determined using cytometry by of flight (CyTOF) and quantitative PCR. Tau spreading was assessed in vivo using tracing of focal tau expression.Results. Trem2 depletion significantly aggravated tau-induced early-onset motor and behavioural deficits. Neuropathologically, Trem2 reduction increased the number of hyperphosphorylated tau lesions in young TAU58 brains and reduced disease-associated microglia. Direct assessment of inter-neuronal spread of tau in vivo revealed significantly enhanced propagation of tau in the absence of Trem2 , suggesting that microglial TREM2 limits the progression of tau pathology in disease.Conclusion. Taken together, our data suggests that reduced TREM2 function accelerates the onset and progression of functional deficits and tau neuropathology in tau transgenic mice, which is - at least in part - due to increased tau spreading. Therefore, reduced TREM2 function may contribute to early AD by augmenting tau toxicity and its inter-neuronal propagation.

scholarly journals Prolonged Glucocorticoid Exposure Does Not Accelerate Telomere Shortening in Cultured Human Fibroblasts

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1425
Author(s):  
Anthony S. Zannas ◽  
Oksana Kosyk ◽  
Calvin S. Leung
Keyword(s):  
Telomere Length ◽  
Psychosocial Stress ◽  
Prolonged Exposure ◽  
Disease Risk ◽  
Human Fibroblasts ◽  
Stress Hormones ◽  
In Vivo Studies ◽  
Biological Aging ◽  
Telomere Shortening

Psychosocial stress, especially when chronic or excessive, can increase disease risk and accelerate biological aging. Although the underlying mechanisms are unclear, in vivo studies have associated exposure to stress and glucocorticoid stress hormones with shorter telomere length. However, the extent to which prolonged glucocorticoid exposure can shorten telomeres in controlled experimental settings remains unknown. Using a well-characterized cell line of human fibroblasts that undergo gradual telomere shortening during serial passaging in culture, we show that prolonged exposure (up to 51 days) to either naturalistic levels of the human endogenous glucocorticoid cortisol or the more potent synthetic glucocorticoid dexamethasone is not sufficient to accelerate telomere shortening. While our findings await extension in other cell types and biological contexts, they indicate that the in vivo association of psychosocial stress with telomere shortening is unlikely to be mediated by a direct and universal glucocorticoid effect on telomere length.

scholarly journals The Human Cytomegalovirus Virion Possesses an Activated Casein Kinase II That Allows for the Rapid Phosphorylation of the Inhibitor of NF-κB, IκBα

2007 ◽  
Vol 81 (10) ◽  
pp. 5305-5314 ◽  
Author(s):  
Maciej T. Nogalski ◽  
Jagat P. Podduturi ◽  
Ian B. DeMeritt ◽  
Liesl E. Milford ◽  
Andrew D. Yurochko
Keyword(s):  
Human Cytomegalovirus ◽  
Molecular Mechanisms ◽  
Kinase Activity ◽  
Human Fibroblasts ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Temporal Regulation ◽  
Protein Kinase Ckii

ABSTRACT We documented that the NF-κB signaling pathway was rapidly induced following human cytomegalovirus (HCMV) infection of human fibroblasts and that this induced NF-κB activity promoted efficient transactivation of the major immediate-early promoter (MIEP). Previously, we showed that the major HCMV envelope glycoproteins, gB and gH, initiated this NF-κB signaling event. However, we also hypothesized that there were additional mechanisms utilized by the virus to rapidly upregulate NF-κB. In this light, we specifically hypothesized that the HCMV virion contained IκBα kinase activity, allowing for direct phosphorylation of IκBα following virion entry into infected cells. In vitro kinase assays performed on purified HCMV virion extract identified bona fide IκBα kinase activity in the virion. The enzyme responsible for this kinase activity was identified as casein kinase II (CKII), a cellular serine-threonine protein kinase. CKII activity was necessary for efficient transactivation of the MIEP and IE gene expression. CKII is generally considered to be a constitutively active kinase. We suggest that this molecular characteristic of CKII represents the biologic rationale for the viral capture and utilization of this kinase early after infection. The packaging of CKII into the HCMV virion identifies that diverse molecular mechanisms are utilized by HCMV for rapid NF-κB activation. We propose that HCMV possesses multiple pathways to increase NF-κB activity to ensure that the correct temporal regulation of NF-κB occurs following infection and that sufficient threshold levels of NF-κB are reached in the diverse array of cells, including monocytes and endothelial cells, infected in vivo.

scholarly journals Persistent organic pollutants and obesity: are they potential mechanisms for breast cancer promotion?

2015 ◽  
Vol 22 (2) ◽  
pp. R69-R86 ◽  
Author(s):  
Denise K Reaves ◽  
Erika Ginsburg ◽  
John J Bang ◽  
Jodie M Fleming
Keyword(s):  
Breast Cancer ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Causal Link ◽  
Model Systems ◽  
Tissue Microenvironment

Dietary ingestion of persistent organic pollutants (POPs) is correlated with the development of obesity. Obesity alters metabolism, induces an inflammatory tissue microenvironment, and is also linked to diabetes and breast cancer risk/promotion of the disease. However, no direct evidence exists with regard to the correlation among all three of these factors (POPs, obesity, and breast cancer). Herein, we present results from current correlative studies indicating a causal link between POP exposure through diet and their bioaccumulation in adipose tissue that promotes the development of obesity and ultimately influences breast cancer development and/or progression. Furthermore, as endocrine disruptors, POPs could interfere with hormonally responsive tissue functions causing dysregulation of hormone signaling and cell function. This review highlights the critical need for advancedin vitroandin vivomodel systems to elucidate the complex relationship among obesity, POPs, and breast cancer, and, more importantly, to delineate their multifaceted molecular, cellular, and biochemical mechanisms. Comprehensivein vitroandin vivostudies directly testing the observed correlations as well as detailing their molecular mechanisms are vital to cancer research and, ultimately, public health.

scholarly journals The tumor suppressor MIR139 is silenced by POLR2M to promote AML oncogenesis

Leukemia ◽  
2021 ◽  
Author(s):  
Christiaan J. Stavast ◽  
Iris van Zuijen ◽  
Elena Karkoulia ◽  
Arman Özçelik ◽  
Antoinette van Hoven-Beijen ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Regulatory Factor ◽  
Molecular Control ◽  
Polycomb Repressive Complex 2 ◽  
Genome Wide ◽  
A Genome

AbstractMIR139 is a tumor suppressor and is commonly silenced in acute myeloid leukemia (AML). However, the tumor-suppressing activities of miR-139 and molecular mechanisms of MIR139-silencing remain largely unknown. Here, we studied the poorly prognostic MLL-AF9 fusion protein-expressing AML. We show that MLL-AF9 expression in hematopoietic precursors caused epigenetic silencing of MIR139, whereas overexpression of MIR139 inhibited in vitro and in vivo AML outgrowth. We identified novel miR-139 targets that mediate the tumor-suppressing activities of miR-139 in MLL-AF9 AML. We revealed that two enhancer regions control MIR139 expression and found that the polycomb repressive complex 2 (PRC2) downstream of MLL-AF9 epigenetically silenced MIR139 in AML. Finally, a genome-wide CRISPR-Cas9 knockout screen revealed RNA Polymerase 2 Subunit M (POLR2M) as a novel MIR139-regulatory factor. Our findings elucidate the molecular control of tumor suppressor MIR139 and reveal a role for POLR2M in the MIR139-silencing mechanism, downstream of MLL-AF9 and PRC2 in AML. In addition, we confirmed these findings in human AML cell lines with different oncogenic aberrations, suggesting that this is a more common oncogenic mechanism in AML. Our results may pave the way for new targeted therapy in AML.

scholarly journals Genome-wide in vivo screen of circulating tumor cells identifies SLIT2 as a regulator of metastasis

2021 ◽  
Author(s):  
Fan Xia ◽  
Yuan Ma ◽  
Kangfu Chen ◽  
Bill Duong ◽  
Sharif Ahmed ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Cellular Migration ◽  
Gene Encoding ◽  
Primary Tumors ◽  
Genome Wide ◽  
Genome Level

Circulating tumor cells (CTCs) break free from primary tumors and travel through the bloodstream and lymphatic system to seed metastatic tumors, which are the major cause of death from cancer. The identification of the major genetic factors that enhance production and persistence of CTCs in the bloodstream at a whole genome level would enable more comprehensive molecular mechanisms of metastasis to be elucidated and the identification of novel therapeutic targets, but this remains a challenging task due to the heterogeneity and extreme rarity of CTCs. Here, we describe the first in vivo genome-wide CRISPR KO screen using CTCs directly isolated from a mouse xenograft. This screen elucidated SLIT2, a gene encoding a secreted protein acting as a cellular migration cue, as the most significantly represented gene knockout in the CTC population. SLIT2 knockout cells are highly metastatic with hypermigratory and mesenchymal phenotype. Loss of SLIT2 is observed in human tumors, indicating its role as a negative modulator of tumor progression and metastasis.

scholarly journals Autophagy in T cells from aged donors is maintained by spermidine, and correlates with function and vaccine responses

2020 ◽  
Author(s):  
Ghada Alsaleh ◽  
Isabel Panse ◽  
Leo Swadling ◽  
Hanlin Zhang ◽  
Alain Meyer ◽  
...  
Keyword(s):  
Older Adults ◽  
T Cells ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Degradation Pathway ◽  
Immune Memory ◽  
Vaccine Responses ◽  
Human T Cells

AbstractOlder adults are at high risk for infectious diseases such as the recent COVID-19 and vaccination seems to be the only long-term solution to the pandemic. While most vaccines are less efficacious in older adults, little is known about the molecular mechanisms that underpin this. Autophagy, a major degradation pathway and one of the few processes known to prevent aging, is critical for the maintenance of immune memory in mice. Here, we show induction of autophagy is specifically induced in human vaccine-induced antigen-specific T cells in vivo. Reduced IFNγ secretion by vaccine-induced T cells in older vaccinees correlates with low autophagy. We demonstrate in human cohorts that levels of the endogenous autophagy-inducing metabolite spermidine, fall with age and supplementing it in vitro recovers autophagy and T cell function. Finally, our data show that endogenous spermidine maintains autophagy via the translation factor eIF5A and transcription factor TFEB. With these findings we have uncovered novel targets and biomarkers for the development of anti-aging drugs for human T cells, providing evidence for the use of spermidine in improving vaccine immunogenicity in the aged human population.

scholarly journals Wine Polyphenols and Neurodegenerative Diseases: An Update on the Molecular Mechanisms Underpinning Their Protective Effects

Beverages ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 96 ◽  
Author(s):  
Paula Silva ◽  
David Vauzour
Keyword(s):  
Neurodegenerative Disorders ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Inverse Correlation ◽  
Protective Effects ◽  
Wine Consumption ◽  
Age Related ◽  
Parkinson’S Diseases

Alzheimer’s and Parkinson’s diseases are the most common age-related and predominantly idiopathic neurodegenerative disorders of unknown pathogenesis. Although there are both clinical and neuropathological features of these diseases that are different, they also share some common aetiologies, such as protein aggregation, mitochondrial dysfunction, oxidative stress, and neuroinflammation. Epidemiological, in vitro and in vivo evidences suggest an inverse correlation between wine consumption and the incidence of neurodegenerative disorders. Wine benefits are, in large part, attributable to the intake of specific polyphenols, which mediate cell function under both normal and pathological conditions. In this review, we aim to provide an overview of the role that wine consumption plays in delaying neurodegenerative disorders. We discuss animal and in vitro studies in support of these actions and we consider how their biological mechanisms at the cellular level may underpin their physiological effects. Together, these data indicate that polyphenols present in wine may hold neuroprotective potential in delaying the onset of neurodegenerative disorders.

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