scholarly journals Translational control in cell ageing: an update

2021 ◽  
Author(s):  
Katrina Woodward ◽  
Nikolay E. Shirokikh
Keyword(s):  
Stress Response ◽  
Translational Control ◽  
Cell Function ◽  
Current Knowledge ◽  
Protein Biosynthesis ◽  
Cell Phenotype ◽  
Proliferative Potential ◽  
Age Related ◽  
Aged Cell ◽  
Translational Mechanisms

Cellular ageing is one of the main drivers of organismal ageing and holds keys towards improving the longevity and quality of the extended life. Elucidating mechanisms underlying the emergence of the aged cells as well as their altered responses to the environment will help understanding the evolutionarily defined longevity preferences across species with different strategies of survival. Much is understood about the role of alterations in the DNA, including many epigenetic modifications such as methylation, in relation to the aged cell phenotype. While transcriptomes of the aged cells are beginning to be better-characterised, their translational responses remain under active investigation. Many of the translationally controlled homeostatic pathways are centred around mitigation of DNA damage, cell stress response and regulation of the proliferative potential of the cells, and thus are critical for the aged cell function. Translation profiling-type studies have boosted the opportunities in discovering the function of protein biosynthesis control and are starting to be applied to the aged cells. Here, we provide a summary of the current knowledge about translational mechanisms considered to be commonly altered in the aged cells, including the integrated stress response-, mechanistic target of Rapamycin- and elongation factor 2 kinase-mediated pathways. We enlist and discuss findings of the recent works that use broad profiling-type approaches to investigate the age-related translational pathways. We outline the limitations of the methods and the remaining unknowns in the established ageing-associated translation mechanisms, and flag translational mechanisms with high prospective importance in ageing, for future studies.

scholarly journals Signal Transduction and Regulatory Mechanisms Involved in Control of the σS (RpoS) Subunit of RNA Polymerase

2002 ◽  
Vol 66 (3) ◽  
pp. 373-395 ◽  
Author(s):  
Regine Hengge-Aronis
Keyword(s):  
Rna Polymerase ◽  
Translational Control ◽  
Current Knowledge ◽  
Response Regulator ◽  
Regulatory System ◽  
Stress Conditions ◽  
Acidic Ph ◽  
High Osmolarity ◽  
Multiple Signal ◽  
Rpos Mrna

SUMMARY The σS (RpoS) subunit of RNA polymerase is the master regulator of the general stress response in Escherichia coli and related bacteria. While rapidly growing cells contain very little σS, exposure to many different stress conditions results in rapid and strong σS induction. Consequently, transcription of numerous σS-dependent genes is activated, many of which encode gene products with stress-protective functions. Multiple signal integration in the control of the cellular σS level is achieved by rpoS transcriptional and translational control as well as by regulated σS proteolysis, with various stress conditions differentially affecting these levels of σS control. Thus, a reduced growth rate results in increased rpoS transcription whereas high osmolarity, low temperature, acidic pH, and some late-log-phase signals stimulate the translation of already present rpoS mRNA. In addition, carbon starvation, high osmolarity, acidic pH, and high temperature result in stabilization of σS, which, under nonstress conditions, is degraded with a half-life of one to several minutes. Important cis-regulatory determinants as well as trans-acting regulatory factors involved at all levels of σS regulation have been identified. rpoS translation is controlled by several proteins (Hfq and HU) and small regulatory RNAs that probably affect the secondary structure of rpoS mRNA. For σS proteolysis, the response regulator RssB is essential. RssB is a specific direct σS recognition factor, whose affinity for σS is modulated by phosphorylation of its receiver domain. RssB delivers σS to the ClpXP protease, where σS is unfolded and completely degraded. This review summarizes our current knowledge about the molecular functions and interactions of these components and tries to establish a framework for further research on the mode of multiple signal input into this complex regulatory system.

scholarly journals Multiple Roles for Cholinergic Signaling from the Perspective of Stem Cell Function

2021 ◽  
Vol 22 (2) ◽  
pp. 666
Author(s):  
Toshio Takahashi
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Function ◽  
Cell Activity ◽  
Embryonic Stem ◽  
Cholinergic Neurons ◽  
Cell Types ◽  
Proliferative Potential ◽  
True Nature ◽  
Cholinergic Signaling

Stem cells have extensive proliferative potential and the ability to differentiate into one or more mature cell types. The mechanisms by which stem cells accomplish self-renewal provide fundamental insight into the origin and design of multicellular organisms. These pathways allow the repair of damage and extend organismal life beyond that of component cells, and they probably preceded the evolution of complex metazoans. Understanding the true nature of stem cells can only come from discovering how they are regulated. The concept that stem cells are controlled by particular microenvironments, also known as niches, has been widely accepted. Technical advances now allow characterization of the zones that maintain and control stem cell activity in several organs, including the brain, skin, and gut. Cholinergic neurons release acetylcholine (ACh) that mediates chemical transmission via ACh receptors such as nicotinic and muscarinic receptors. Although the cholinergic system is composed of organized nerve cells, the system is also involved in mammalian non-neuronal cells, including stem cells, embryonic stem cells, epithelial cells, and endothelial cells. Thus, cholinergic signaling plays a pivotal role in controlling their behaviors. Studies regarding this signal are beginning to unify our understanding of stem cell regulation at the cellular and molecular levels, and they are expected to advance efforts to control stem cells therapeutically. The present article reviews recent findings about cholinergic signaling that is essential to control stem cell function in a cholinergic niche.

scholarly journals Age related extracellular matrix and interstitial cell phenotype in pulmonary valves

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaohua Wu ◽  
Vikas Kumar ◽  
Peng Xiao ◽  
Mitchell Kuss ◽  
Jung Yul Lim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Heart Valve ◽  
Cell Phenotype ◽  
Primary Concern ◽  
Ross Operation ◽  
Age Related ◽  
Cardiovascular Morbidity And Mortality ◽  
Extracellular Matrix Components ◽  
Matrix Components

AbstractHeart valve disease is a common manifestation of cardiovascular disease and is a significant cause of cardiovascular morbidity and mortality worldwide. The pulmonary valve (PV) is of primary concern because of its involvement in common congenital heart defects, and the PV is usually the site for prosthetic replacement following a Ross operation. Although effects of age on valve matrix components and mechanical properties for aortic and mitral valves have been studied, very little is known about the age-related alterations that occur in the PV. In this study, we isolated PV leaflets from porcine hearts in different age groups (~ 4–6 months, denoted as young versus ~ 2 years, denoted as adult) and studied the effects of age on PV leaflet thickness, extracellular matrix components, and mechanical properties. We also conducted proteomics and RNA sequencing to investigate the global changes of PV leaflets and passage zero PV interstitial cells in their protein and gene levels. We found that the size, thickness, elastic modulus, and ultimate stress in both the radial and circumferential directions and the collagen of PV leaflets increased from young to adult age, while the ultimate strain and amount of glycosaminoglycans decreased when age increased. Young and adult PV had both similar and distinct protein and gene expression patterns that are related to their inherent physiological properties. These findings are important for us to better understand the physiological microenvironments of PV leaflet and valve cells for correctively engineering age-specific heart valve tissues.

scholarly journals Hypoxia and Hypoxia-Inducible Factor Signaling in Muscular Dystrophies: Cause and Consequences

2021 ◽  
Vol 22 (13) ◽  
pp. 7220
Author(s):  
Thuy-Hang Nguyen ◽  
Stephanie Conotte ◽  
Alexandra Belayew ◽  
Anne-Emilie Declèves ◽  
Alexandre Legrand ◽  
...  
Keyword(s):  
Cell Function ◽  
Current Knowledge ◽  
Genetic Defect ◽  
Hypoxia Inducible Factor ◽  
Muscular Dystrophies ◽  
Compensatory Mechanisms ◽  
Hypoxia Response ◽  
Muscle Disorders ◽  
Almost All ◽  
The Impact

Muscular dystrophies (MDs) are a group of inherited degenerative muscle disorders characterized by a progressive skeletal muscle wasting. Respiratory impairments and subsequent hypoxemia are encountered in a significant subgroup of patients in almost all MD forms. In response to hypoxic stress, compensatory mechanisms are activated especially through Hypoxia-Inducible Factor 1 α (HIF-1α). In healthy muscle, hypoxia and HIF-1α activation are known to affect oxidative stress balance and metabolism. Recent evidence has also highlighted HIF-1α as a regulator of myogenesis and satellite cell function. However, the impact of HIF-1α pathway modifications in MDs remains to be investigated. Multifactorial pathological mechanisms could lead to HIF-1α activation in patient skeletal muscles. In addition to the genetic defect per se, respiratory failure or blood vessel alterations could modify hypoxia response pathways. Here, we will discuss the current knowledge about the hypoxia response pathway alterations in MDs and address whether such changes could influence MD pathophysiology.

Supplementation with Selenium Restores Age-Related Decline in Immune Cell Function

1995 ◽  
Vol 209 (4) ◽  
pp. 369-375 ◽  
Author(s):  
M. Roy ◽  
L. Kiremidjian-Schumacher ◽  
H. I. Wishe ◽  
M. W. Cohen ◽  
G. Stotzky
Keyword(s):  
Cell Function ◽  
Immune Cell ◽  
Immune Cell Function ◽  
Age Related

scholarly journals Age-Related Mitochondrial DNA Depletion and the Impact on Pancreatic Beta Cell Function

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e115433 ◽  
Author(s):  
Donna L. Nile ◽  
Audrey E. Brown ◽  
Meutia A. Kumaheri ◽  
Helen R. Blair ◽  
Alison Heggie ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Beta Cell ◽  
Beta Cell Function ◽  
Cell Function ◽  
Pancreatic Beta Cell ◽  
Age Related ◽  
Mitochondrial Dna Depletion ◽  
Pancreatic Beta Cell Function ◽  
The Impact

Hairless regulates heterochromatin maintenance and muscle stem cell function as a histone demethylase antagonist

2021 ◽  
Vol 118 (37) ◽  
pp. e2025281118
Author(s):  
Ling Liu ◽  
Cristina Rodriguez-Mateo ◽  
Polly Huang ◽  
Albin Huang ◽  
Alexander Lieu ◽  
...  
Keyword(s):  
Cell Function ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Genotoxic Stress ◽  
Histone Demethylases ◽  
Muscle Stem Cell ◽  
Muscle Stem Cells ◽  
Histone 3 ◽  
Age Related ◽  
Regenerative Ability

Skeletal muscle possesses remarkable regenerative ability because of the resident muscle stem cells (MuSCs). A prominent feature of quiescent MuSCs is a high content of heterochromatin. However, little is known about the mechanisms by which heterochromatin is maintained in MuSCs. By comparing gene-expression profiles from quiescent and activated MuSCs, we found that the mammalian Hairless (Hr) gene is expressed in quiescent MuSCs and rapidly down-regulated upon MuSC activation. Using a mouse model in which Hr can be specifically ablated in MuSCs, we demonstrate that Hr expression is critical for MuSC function and muscle regeneration. In MuSCs, loss of Hr results in reduced trimethylated Histone 3 Lysine 9 (H3K9me3) levels, reduced heterochromatin, increased susceptibility to genotoxic stress, and the accumulation of DNA damage. Deletion of Hr leads to an acceleration of the age-related decline in MuSC numbers. We have also demonstrated that despite the fact that Hr is homologous to a family of histone demethylases and binds to di- and trimethylated H3K9, the expression of Hr does not lead to H3K9 demethylation. In contrast, we show that the expression of Hr leads to the inhibition of the H3K9 demethylase Jmjd1a and an increase in H3K9 methylation. Taking these data together, our study has established that Hr is a H3K9 demethylase antagonist specifically expressed in quiescent MuSCs.

STEM-10. UPSTREAM REGULATORS OF THE GLIOMA STEM CELL PHENOTYPE

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi23-vi23
Author(s):  
Alexandra Calinescu ◽  
Zain Sultan ◽  
McKenzie Kauss ◽  
Wajd Al-Holou ◽  
Jason Heth
Keyword(s):  
Stem Cells ◽  
Tumor Grade ◽  
Telomerase Activity ◽  
Primary Brain Tumor ◽  
Tumor Formation ◽  
High Expression ◽  
Cell Phenotype ◽  
Proliferative Potential ◽  
Loss Of Function ◽  
Significant Enrichment

Abstract Glioblastoma (GBM) is the most common and deadly primary brain tumor in adults. Recurrence of the disease is attributed in part to the presence of Glioma Stem Cells (GSC), which are resistant to chemo- and radiotherapy and can initiate tumor formation. Molecularly, GSCs resemble the mesenchymal subtype that is associated with worse prognosis. GSCs share many characteristics with Neural Stem Cells (NSCs) including proliferative potential, migratory capacity, telomerase activity, diverse progeny and similar gene signature, however differ fundamentally from NSCs in their tumor forming ability. RNA-Seq analysis of GSCs and NSCs illustrates significant enrichment in GSCs of transcription factors (TFs) known to be dysregulated in cancer, chief among them being SIX1, a developmental TF with documented roles in progression of multiple cancers. Overexpression of SIX1 in A172 GBM cells enhances proliferation, promotes resistance to radiotherapy and alters expression of a core set of 4 developmental TFs (POU3F2, SALL2, OLIG2 and SOX2) capable to reprogram differentiated GBM cells into GSCs (Suva et al., 2014). Analysis of SIX1 in surgical samples from glioma patients illustrates that high expression of SIX1 correlates with tumor grade, finding corroborated in the TCGA and CGGA data sets. Surprisingly, primary NSCs, after extended time in culture, increase their proliferation rate, acquire a mesenchymal transcriptional signature akin to GSCs, including high expression of SIX1, and form deadly tumors when implanted into the brains of mice. Comparing the epigenetic landscape of transformed and normal NSCs we identify a significant enrichment of accessible chromatin at promoter and enhancer loci in transformed NSCs, including at regulatory regions of SIX1 and of genes that define mesenchymal GBM. These data suggest that SIX1 may represent an upstream regulator of the GSC phenotype and may drive malignant transformation of NSCs. Genetic and epigenetic loss of function analyses are ongoing to test this hypothesis.

scholarly journals Proteogenomic Analysis of Burkholderia Species Strains 25 and 46 Isolated from Uraniferous Soils Reveals Multiple Mechanisms to Cope with Uranium Stress

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 269 ◽  
Author(s):  
Meenakshi Agarwal ◽  
Ashish Pathak ◽  
Rajesh Rathore ◽  
Om Prakash ◽  
Rakesh Singh ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Stress Response ◽  
Proteomic Analysis ◽  
Protein Biosynthesis ◽  
Draft Genome ◽  
Department Of Energy ◽  
Coding Sequences ◽  
Total Rna ◽  
A Genome ◽  
Rna Genes

Two Burkholderia spp. (strains SRS-25 and SRS-46) were isolated from high concentrations of uranium (U) from the U.S. Department of Energy (DOE)-managed Savannah River Site (SRS). SRS contains soil gradients that remain co-contaminated by heavy metals from previous nuclear weapons production activities. Uranium (U) is one of the dominant contaminants within the SRS impacted soils, which can be microbially transformed into less toxic forms. We established microcosms containing strains SRS-25 and SRS-46 spiked with U and evaluated the microbially-mediated depletion with concomitant genomic and proteomic analysis. Both strains showed a rapid depletion of U; draft genome sequences revealed SRS-25 genome to be of approximately 8,152,324 bp, a G + C content of 66.5, containing a total 7604 coding sequences with 77 total RNA genes. Similarly, strain SRS-46 contained a genome size of 8,587,429 bp with a G + C content of 67.1, 7895 coding sequences, with 73 total RNA genes, respectively. An in-depth, genome-wide comparisons between strains 25, 46 and a previously isolated strain from our research (Burkholderia sp. strain SRS-W-2-2016), revealed a common pool of 3128 genes; many were found to be homologues to previously characterized metal resistance genes (e.g., for cadmium, cobalt, and zinc), as well as for transporter, stress/detoxification, cytochromes, and drug resistance functions. Furthermore, proteomic analysis of strains with or without U stress, revealed the increased expression of 34 proteins from strain SRS-25 and 52 proteins from strain SRS-46; similar to the genomic analyses, many of these proteins have previously been shown to function in stress response, DNA repair, protein biosynthesis and metabolism. Overall, this comparative proteogenomics study confirms the repertoire of metabolic and stress response functions likely rendering the ecological competitiveness to the isolated strains for colonization and survival in the heavy metals contaminated SRS soil habitat.

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