Search results for "Homeostasis"
showing 10 items of 630 documents
The histone deacetylase Rpd3 regulates the heterochromatin structure of Drosophila telomeres
2011
Telomeres are specialized structures at the end of eukaryotic chromosomes that are required to preserve genome integrity, chromosome stability and nuclear architecture. Telomere maintenance and function are established epigenetically in several eukaryotes. However, the exact chromatin enzymatic modifications regulating telomere homeostasis are poorly understood. In Drosophila melanogaster, telomere length and stability are maintained through the retrotransposition of specialized telomeric sequences and by the specific loading of protecting capping proteins, respectively. Here, we show that the loss of the essential and evolutionarily conserved histone deacetylase Rpd3, the homolog of mammal…
Protective effect of paraoxonase-2 against endoplasmic reticulum stress-induced apoptosis is lost upon disturbance of calcium homoeostasis
2008
PON2 (paraoxonase-2) is a ubiquitously expressed antioxidative protein which is largely found in the ER (endoplasmic reticulum). Addressing the cytoprotective functions of PON2, we observed that PON2 overexpression provided significant resistance to ER-stress-induced caspase 3 activation when the ER stress was induced by interference with protein modification (by tunicamycin or dithiothreitol), but not when ER stress was induced by disturbance of Ca2+ homoeostasis (by thapsigargin or A23187). When analysing the underlying molecular events, we found an activation of the PON2 promoter in response to all tested ER-stress-inducing stimuli. However, only tunicamycin and dithiothreitol resulted i…
''Deferoxamine blocks death induced by glutathione depletion in PC 12 cells''
2013
Chouraqui, E. | Leon, A. | Repesse, Y. | Prigent-Tessier, A. | Bouhallab, S. | Bougle, D. | Marie, C. | Duval, D.; International audience; ''The purpose of the present work was to investigate the mechanisms by which glutathione depletion induced by treatment with buthionine sulfoximine (BSO) led within 24-30 h to PC 12 cells apoptosis. Our results showed that treatment by relatively low concentrations (10-30 mu M) of deferoxamine (DFx), a natural iron-specific chelator, almost completely shielded the cells from BSO-induced toxicity and that DFx still remained protective when added up to 9-12 h after BSO treatment. On the other hand, phosphopeptides derived from milk casein and known to carr…
A central nervous system-focused treatment approach for people with frozen shoulder: protocol for a randomized clinical trial
2019
Background: Frozen shoulder (FS) is a musculoskeletal condition of poorly understood etiology that results in shoulder pain and large mobility deficits. Despite some physical therapy interventions, such as joint mobilization and exercise, having shown therapeutic benefit, a definitive treatment does not currently exist. The aim of this study will be to compare the effectiveness of a central nervous system (CNS)-directed treatment program versus a standard medical and physical therapy care program on outcomes in participants with FS. Methods/design: The study is a two-group, randomized clinical trial with blinding of participants and assessors. Participants will be recruited via referrals fr…
Impact of Chaperonopathies in Protein Homeostasis and Beyond
2013
Chaperones have functions other than those classically attributed to them pertaining to protein homeostasis. These “other” non-canonical functions are the focus of chapter 8. The close interaction of the chaperoning and the immune systems and the impact of their malfunctioning on aging and cancer are highlighted. Conversely, the impact of ageing and cancer on the two systems is also underscored. The connections between stress, protein damage (including chaperones), protein misfolding, protein aggregation and precipitation, and tissue degeneration, are analyzed, indicating that all these processes are aggravated by a decline in chaperoning potential with aging (chaperonopathies of the aged) …
Topiramate and Metabolic Acidosis in Infants and Toddlers
2002
Summary: Purpose: Topiramate (TPM) inhibits carbonic anhydrase, with metabolic acidosis as a possible side effect, although this has been reported in only two adult cases. We investigated the acid–base metabolism in infants and toddlers treated with TPM. Methods: Nine infants and toddlers aged 5 months to 2.3 years (median, 6 months) were treated with TPM at maximal doses of 8.2–26 mg/kg/day (median, 11 mg/kg/day). The maximal TPM dose was achieved after 8–35 days (median, 17 days). TPM was given in addition to other antiepileptic drugs (AEDs) in five cases and as a sole AED in four patients with refractory epilepsy resistant to multiple AEDs. The diagnoses were infantile spasms (n = 5), e…
Iron Regulatory Mechanisms in Saccharomyces cerevisiae
2020
Iron is an essential micronutrient for all eukaryotic organisms because it participates as a redox cofactor in many cellular processes. However, excess iron can damage cells since it promotes the generation of reactive oxygen species. The budding yeast Saccharomyces cerevisiae has been used as a model organism to study the adaptation of eukaryotic cells to changes in iron availability. Upon iron deficiency, yeast utilizes two transcription factors, Aft1 and Aft2, to activate the expression of a set of genes known as the iron regulon, which are implicated in iron uptake, recycling and mobilization. Moreover, Aft1 and Aft2 activate the expression of Cth2, an mRNA-binding protein that limits t…
Single cell RNAseq provides a molecular and cellular cartography of changes to the human endometrium through the menstrual cycle
2018
SummaryIn a human menstrual cycle, the endometrium undergoes remodeling, shedding, and regeneration, all of which are driven by substantial gene expression changes in the underlying cellular hierarchy. Despite its importance in human fertility and regenerative biology, mechanistic understanding of this unique type of tissue homeostasis remains rudimentary. We characterized the transcriptomic transformation of human endometrium at single cell resolution, dissecting the multidimensional cellular heterogeneity of this tissue across the entire natural menstrual cycle. We profiled the behavior of 6 endometrial cell types, including a previously uncharacterized ciliated epithelial cell type, duri…
Early life stress programming of NG2+ glia transcriptome alters functional properties of voltage gated sodium (Nav) channels and cognitive performance
2020
AbstractThe precise mechanisms underlying the detrimental effects of early life stress (ELS) on adult mental health remain still elusive. To date, most studies have exclusively targeted neuronal populations and not considered neuron-glia crosstalk as a crucially important element for the integrity of stress-related brain function. Here, we have investigated the impact of ELS on a glial subpopulation with unique properties in brain homeostasis, the NG2+ cells. ELS shifted the NG2+ transcriptome towards more mature stages, and these transcriptional effects were dependent on stress-induced glucocorticoids. The functional relevance of one candidate gene, Scn7a, could be confirmed by an increase…
Homeostasis in the Central Dogma of molecular biology: the importance of mRNA instability
2019
Cell survival requires the control of biomolecule concentration, i.e. biomolecules should approach homeostasis. With information-carrying macromolecules, the particular concentration variation ranges depend on each type: DNA is not buffered, but mRNA and protein concentrations are homeostatically controlled, which leads to the ribostasis and proteostasis concepts. In recent years, we have studied the particular features of mRNA ribostasis and proteostasis in the model organism S. cerevisiae. Here we extend this study by comparing published data from three other model organisms: E. coli, S. pombe and cultured human cells. We describe how mRNA ribostasis is less strict than proteostasis. A co…