Search results for "quiescence"
showing 10 items of 15 documents
Neural Stem Cell Regulation by Adhesion Molecules Within the Subependymal Niche
2019
In the mammalian adult brain, neural stem cells persist in neurogenic niches. The subependymal zone is the most prolific neurogenic niche in adult rodents, where residing stem cells generate large numbers of immature neurons that migrate into the olfactory bulb, where they differentiate into different types of interneurons. Subependymal neural stem cells derive from embryonic radial glia and retain some of their features like apico-basal polarity, with apical processes piercing the ependymal layer, and a basal process contacting blood vessels, constituting an epithelial niche. Conservation of the cytoarchitecture of the niche is of crucial importance for the maintenance of stem cells and fo…
Estrogen Regulates the Satellite Cell Compartment in Females
2019
SUMMARY Skeletal muscle mass, strength, and regenerative capacity decline with age, with many measures showing a greater deterioration in females around the time estrogen levels decrease at menopause. Here, we show that estrogen deficiency severely compromises the maintenance of muscle stem cells (i.e., satellite cells) as well as impairs self-renewal and differentiation into muscle fibers. Mechanistically, by hormone replacement, use of a selective estrogen-receptor modulator (bazedoxifene), and conditional estrogen receptor knockout, we implicate 17β-estradiol and satellite cell expression of estrogen receptor α and show that estrogen signaling through this receptor is necessary to preven…
Improved Properties of the Big Five Inventory and the Rosenberg Self-Esteem Scale in the Expanded Format Relative to the Likert Format.
2019
Previous research by Zhang and Savalei (2015) proposed an alternative scale format to the Likert scale format: the Expanded format. Scale items in the Expanded format present both positively worded and negatively worded sentences as response options for each scale item; therefore, they were less affected by the acquiescence bias and method effects that often occur in the Likert scale items. The major goal of the current study is to further demonstrate the superiority of the Expanded format to the Likert format across different psychological scales. Specifically, we aim to replicate the findings of Zhang and Savalei and to determine whether order effect exists in the Expanded format scales. …
Quiescence Modulates Stem Cell Maintenance and Regenerative Capacity in the Aging Brain.
2018
The function of somatic stem cells declines with age. Understanding the molecular underpinnings of this decline is key to counteract age-related disease. Here, we report a dramatic drop in the neural stem cells (NSCs) number in the aging murine brain. We find that this smaller stem cell reservoir is protected from full depletion by an increase in quiescence that makes old NSCs more resistant to regenerate the injured brain. Once activated, however, young and old NSCs show similar proliferation and differentiation capacity. Single-cell transcriptomics of NSCs indicate that aging changes NSCs minimally. In the aging brain, niche-derived inflammatory signals and the Wnt antagonist sFRP5 induce…
¿El Estado de Derecho en peligro? El juez constitucional contra la Constitución y a favor de la reelección presidencial indefinida : caso Bolivia
2021
In Bolivia, the third term and the habilitation of former President Evo Morales to the 2019 presidential elections was allowed with the acquiescence of the Plurinational Constitutional Court. Despite the fact that the Constitution prohibited it and there was a referendum that rejected indefinite presidential re-election. This occurred through the judicialization of politics that produced a non-formal reform of the Constitution producing a case of abusive constitutionalism and the destabilization of the rule of law.
Unveiling neural stem cell quiescence: a crosstalk with the extracellular matrix niche
2023
Neural stem cells (NSCs) in the subependymal zone (SEZ) reside in a very specialized microenvironment that tightly regulates their activation state. Three NSC populations coexist in the niche, quiescent (qNSCs), primed and activated (aNSCs), which display unique, actively modulated, molecular identities. One of the specialized extrinsic properties that affect NSC quiescence-to-activation transitions is the extracellular matrix (ECM). The SEZ is the only region in the whole mouse brain that has two basement membrane (BM) structures: vascular and speckled BMs. Further, it displays higher stiffness compared to non-neurogenic areas, suggesting that both composition and ECM properties could part…
Individual and culture-level components of survey response styles: A multi-level analysis using cultural models of selfhood
2016
Variations in acquiescence and extremity pose substantial threats to the validity of cross-cultural research that relies on survey methods. Individual and cultural correlates of response styles when using 2 contrasting types of response mode were investigated, drawing on data from 55 cultural groups across 33 nations. Using 7 dimensions of self-other relatedness that have often been confounded within the broader distinction between independence and interdependence, our analysis yields more specific understandings of both individual- and culture-level variations in response style. When using a Likert-scale response format, acquiescence is strongest among individuals seeing themselves as simi…
A Post-contentious Turning Point for the Contentious French? Crisis Without Protest in France
2018
International audience; This chapter shows that the ‘contentious French’ may not be that contentious anymore. The economic crisis provides a unique chance to argue that a post-contentious turning point is emerging in spite of a long-standing tradition of protesting. Yet the chapter suggests that this post-contentious turning point is not bringing about acquiescence but opens space for new forms of political participation, especially in connection with resources acquired through employment and educational track. In this case, we find a more extensive engagement in online activism and non-institutional forms of political participation, that is, the two forms of political participation that ar…
STRIPAK Members Orchestrate Hippo and Insulin Receptor Signaling to Promote Neural Stem Cell Reactivation
2019
Summary Adult stem cells reactivate from quiescence to maintain tissue homeostasis and in response to injury. How the underlying regulatory signals are integrated is largely unknown. Drosophila neural stem cells (NSCs) also leave quiescence to generate adult neurons and glia, a process that is dependent on Hippo signaling inhibition and activation of the insulin-like receptor (InR)/PI3K/Akt cascade. We performed a transcriptome analysis of individual quiescent and reactivating NSCs harvested directly from Drosophila brains and identified the conserved STRIPAK complex members mob4, cka, and PP2A (microtubule star, mts). We show that PP2A/Mts phosphatase, with its regulatory subunit Widerbors…
Hematopoietic Stem Cells Reversibly Switch from Dormancy to Self-Renewal during Homeostasis and Repair
2008
Bone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1(+)cKit(+)CD150(+)CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of th…