scholarly journals Hyaluronan-Based Three-Dimensional Microenvironment Potently Induces Cardiovascular Progenitor Cell Populations

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Jessica M. Gluck ◽  
Jennifer Chyu ◽  
Connor Delman ◽  
Sepideh Heydarkhan-Hagvall ◽  
W. Robb MacLellan ◽  
...  

The relationship between stem cell niches in vivo and their surrounding microenvironment is still relatively unknown. Recent advances have indicated that extrinsic factors within the cardiovascular progenitor cell niche influence maintenance of a multipotent state as well as drive cell-fate decisions. We have previously shown the direct effects of extracellular matrix (ECM) proteins and have now investigated the effects of dimension on the induction of a cardiovascular progenitor cell (CPC) population. We have shown here that the three-dimensionality of a hyaluronan-based hydrogel greatly induces a CPC population, as marked by Flk-1. We have compared the effects of a 3D microenvironment to those of conventional 2D cell culture practices and have found that the 3D microenvironment potently induces a progenitor cell state.

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1055-1067 ◽  
Author(s):  
Z.D. Ezzeddine ◽  
X. Yang ◽  
T. DeChiara ◽  
G. Yancopoulos ◽  
C.L. Cepko

Lineage analyses of vertebrate retinae have led to the suggestions that cell fate decisions are made during or after the terminal cell division and that extrinsic factors can influence fate choices. The evidence for a role of extrinsic factors is strongest for development of rodent rod photoreceptors ('rods'). In an effort to identify molecules that may regulate rod development, a number of known factors were assayed in vitro. Ciliary neurotrophic factor (CNTF) was found to have a range of effects on retinal cells. Addition of CNTF to postnatal rat retinal explants resulted in a dramatic reduction in the number of differentiating rods. Conversly, the number of cells expressing markers of bipolar cell differentiation was increased to a level not normally seen in vivo or in vitro. In addition, a small increase in the percentage of cells expressing either a marker of amacrine cells or a marker of Muller glia was noted. It was determined that many of the cells that would normally differentiate into rods were the cells that differentiated as bipolar cells in the presence of CNTF. Prospective rod photoreceptors could make this change even when they were postmitotic, indicating that at least a subset of cells fated to be rods were not committed to this fate at the time they were born. These findings highlight the distinction between cell fate and commitment. Resistance to the effect of CNTF on rod differentiation occurred at about the time that a cell began to express opsin. The time of commitment to terminal rod differentiation may thus coincide with the initiation of opsin expression. In agreement with the hypothesis that CNTF plays a role in rod differentiation in vivo, a greater percentage of cells were observed differentiating as rod photoreceptors in mouse retinal explants lacking a functional CNTF receptor, relative to wild-type littermates.


Author(s):  
Satish Kumar Tiwari ◽  
Sudip Mandal

Over the years, Drosophila has served as a wonderful genetically tractable model system to unravel various facets of tissue-resident stem cells in their microenvironment. Studies in different stem and progenitor cell types of Drosophila have led to the discovery of cell-intrinsic and extrinsic factors crucial for stem cell state and fate. Though initially touted as the ATP generating machines for carrying various cellular processes, it is now increasingly becoming clear that mitochondrial processes alone can override the cellular program of stem cells. The last few years have witnessed a surge in our understanding of mitochondria’s contribution to governing different stem cell properties in their subtissular niches in Drosophila. Through this review, we intend to sum up and highlight the outcome of these in vivo studies that implicate mitochondria as a central regulator of stem cell fate decisions; to find the commonalities and uniqueness associated with these regulatory mechanisms.


2020 ◽  
Author(s):  
Darshika Tomer ◽  
Sudipto Munshi ◽  
Brianna E. Alexander ◽  
Brenda French ◽  
Pavan Vedula ◽  
...  

AbstractThe regulation of cell fate decisions, morphogenesis, and responses to injury are intimately linked to the process of Fn1 fibrillogenesis. Live imaging and super-resolution microscopy revealed that Fn1 fibrils are not continuous. Instead, Fn1 fibrils arise from nanodomains containing multiple Fn1 dimers. As they move toward cell center, Fn1 nanodomains become organized into linear arrays with a spacing of 130 nm between the nanodomains, with little Fn1 in between; Fn1 nanodomain arrays are resistant to deoxycholate treatment demonstrating that these beaded assemblies are indeed mature Fn1 fibrils. FUD, a bacterial peptide that disrupts Fn1 fibrillogenesis, does not disrupt nanodomain formation; instead, it interferes with the organization of nanodomains into arrays. The nanodomain composition of Fn1 fibrils is observed in multiple contexts: in three-dimensional ECM in vivo, on substrata of different composition and stiffness, and is retained in the absence of cells. The modular architecture of Fn1 fibrils bears important implications for mechanisms of ECM remodeling and signal transduction.


2005 ◽  
Vol 202 (11) ◽  
pp. 1599-1611 ◽  
Author(s):  
Emmanuelle Passegué ◽  
Amy J. Wagers ◽  
Sylvie Giuriato ◽  
Wade C. Anderson ◽  
Irving L. Weissman

Knowledge of the molecular networks controlling the proliferation and fate of hematopoietic stem cells (HSC) is essential to understand their function in maintaining blood cell production during normal hematopoiesis and upon clinical transplantation. Using highly purified stem and progenitor cell populations, we define the proliferation index and status of the cell cycle machinery at discrete stages of hematopoietic differentiation and during cytokine-mediated HSC mobilization. We identify distinct sets of cell cycle proteins that specifically associate with differentiation, self-renewal, and maintenance of quiescence in HSC and progenitor cells. Moreover, we describe a striking inequality of function among in vivo cycling and quiescent HSC by demonstrating that their long-term engraftment potential resides predominantly in the G0 fraction. These data provide a direct link between HSC proliferation and function and identify discrete molecular targets in regulating HSC cell fate decisions that could have implications for both the therapeutic use of HSC and the understanding of leukemic transformation.


2015 ◽  
Author(s):  
Adam L MacLean ◽  
Paul Kirk ◽  
Michael PH Stumpf

Within populations of cells, fate decisions are controlled by an indeterminate combination of cell-intrinsic and cell-extrinsic factors. In the case of stem cells, the stem cell niche is believed to maintain "stemness" through communication and interactions between the stem cells and one or more other cell-types that contribute to the niche conditions. To investigate the robustness of cell fate decisions in the stem cell hierarchy and the role that the niche plays, we introduce simple mathematical models of stem and progenitor cells, their progeny and their interplay in the niche. These models capture the fundamental processes of proliferation and differentiation and allow us to consider alternative possibilities regarding how niche-mediated signalling feedback regulates the niche dynamics. Generalised stability analysis of these stem cell niche systems enables us to describe the stability properties of each model. We find that although the number of feasible states depends on the model, their probabilities of stability in general do not: stem cell--niche models are stable across a wide range of parameters. We demonstrate that niche-mediated feedback increases the number of stable steady states, and show how distinct cell states have distinct branching characteristics. The ecological feedback and interactions mediated by the stem cell niche thus lend (surprisingly) high levels of robustness to the stem and progenitor cell population dynamics. Furthermore, cell--cell interactions are sufficient for populations of stem cells and their progeny to achieve stability and maintain homeostasis. We show that the robustness of the niche -- and hence of the stem cell pool in the niche -- depends only weakly, if at all, on the complexity of the niche make-up: simple as well as complicated niche systems are capable of supporting robust and stable stem cell dynamics.


Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2422
Author(s):  
Oleg Timofeev ◽  
Thorsten Stiewe

p53 is a tumor suppressor that is mutated in half of all cancers. The high clinical relevance has made p53 a model transcription factor for delineating general mechanisms of transcriptional regulation. p53 forms tetramers that bind DNA in a highly cooperative manner. The DNA binding cooperativity of p53 has been studied by structural and molecular biologists as well as clinical oncologists. These experiments have revealed the structural basis for cooperative DNA binding and its impact on sequence specificity and target gene spectrum. Cooperativity was found to be critical for the control of p53-mediated cell fate decisions and tumor suppression. Importantly, an estimated number of 34,000 cancer patients per year world-wide have mutations of the amino acids mediating cooperativity, and knock-in mouse models have confirmed such mutations to be tumorigenic. While p53 cancer mutations are classically subdivided into “contact” and “structural” mutations, “cooperativity” mutations form a mechanistically distinct third class that affect the quaternary structure but leave DNA contacting residues and the three-dimensional folding of the DNA-binding domain intact. In this review we discuss the concept of DNA binding cooperativity and highlight the unique nature of cooperativity mutations and their clinical implications for cancer therapy.


Cell Reports ◽  
2021 ◽  
Vol 34 (10) ◽  
pp. 108818
Author(s):  
Luca Orlando ◽  
Borko Tanasijevic ◽  
Mio Nakanishi ◽  
Jennifer C. Reid ◽  
Juan L. García-Rodríguez ◽  
...  

Author(s):  
Karen Perta ◽  
Eileen Kalmar ◽  
Youkyung Bae

Purpose The aim of the study was to update our information regarding the salpingopharyngeus (SP) muscle using cadaveric and in vivo magnetic resonance imaging (MRI) data. Primary objectives were to (a) observe the presence/absence of the muscle and (b) quantify and describe its dimensions and course. Method SP specimens from 19 cadavers (10 women, nine men) were analyzed. Following head bisection, measurements of SP, including width of the cartilaginous attachment (CW) and width of the superior muscle base (SMW), were taken before and after removal of the overlying mucosa. In addition, SP was analyzed in 15 healthy subjects (eight men, seven women) using high-resolution three-dimensional MRI data. CW and SMW measures were replicated in the paraxial MRI view. Results The presence of the salpingopharyngeal fold and muscle was confirmed bilaterally in all cadaveric and living subjects. Following mucosa removal, mean cadaveric CW and SMW measurements were 5.6 and 3.8 mm, respectively. Mean in vivo CW and SMW were 6.1 and 3.7 mm, respectively. Results from the hierarchical regression analyses revealed that, in both cadaveric and living groups, SMW is dependent on the relationship between age and body weight, after controlling for sex. Conclusions The salpingopharyngeal fold and SP muscle are always present bilaterally and can be quantified at the superior origin using both cadaveric and in vivo three-dimensional MRI data. Though both the superior origin and inferior course of SP are highly variable, the size of the SP muscle is dependent on characteristics known to affect muscle fibers, such as the relationship between age and body weight. Given the consistent and quantifiable presence of the SP muscle, its potential role in velopharyngeal function for speech and swallowing is reconsidered. Supplemental Material https://doi.org/10.23641/asha.14347859


Author(s):  
Emma Carley ◽  
Rachel K. Stewart ◽  
Abigail Zieman ◽  
Iman Jalilian ◽  
Diane. E. King ◽  
...  

AbstractWhile the mechanisms by which chemical signals control cell fate have been well studied, how mechanical inputs impact cell fate decisions are not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells, and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate.


Author(s):  
Anoeska Agatha Alida van de Moosdijk ◽  
Yorick Bernardus Cornelis van de Grift ◽  
Saskia Madelon Ada de Man ◽  
Amber Lisanne Zeeman ◽  
Renée van Amerongen

AbstractWnt signal transduction controls tissue morphogenesis, maintenance and regeneration in all multicellular animals. In mammals, the WNT/CTNNB1 (Wnt/β-catenin) pathway controls cell proliferation and cell fate decisions before and after birth. It plays a critical role at multiple stages of embryonic development, but also governs stem cell maintenance and homeostasis in adult tissues. However, it remains challenging to monitor endogenous WNT/CTNNB1 signaling dynamics in vivo. Here we report the generation and characterization of a new knock-in mouse strain that doubles as a fluorescent reporter and lineage tracing driver for WNT/CTNNB1 responsive cells. We introduced a multi-cistronic targeting cassette at the 3’ end of the universal WNT/CTNNB1 target gene Axin2. The resulting knock-in allele expresses a bright fluorescent reporter (3xNLS-SGFP2) and a doxycycline-inducible driver for lineage tracing (rtTA3). We show that the Axin2P2A-rtTA3-T2A-3xNLS-SGFP2 strain labels WNT/CTNNB1 cells at multiple anatomical sites during different stages of embryonic and postnatal development. It faithfully reports the subtle and dynamic changes in physiological WNT/CTNNB1 signaling activity that occur in vivo. We expect this mouse strain to be a useful resource for biologists who want to track and trace the location and developmental fate of WNT/CTNNB1 responsive stem cells in different contexts.Abstract Figure


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