The behavioral and developmental physiology of nematocysts

2002 ◽  
Vol 80 (10) ◽  
pp. 1772-1794 ◽  
Author(s):  
G Kass-Simon ◽  
A A Scappaticci, Jr.
Keyword(s):  
Stem Cells ◽  
Frequency Response ◽  
Electrical Signal ◽  
Sensory Cells ◽  
Mechanical Stimuli ◽  
Functional Categories ◽  
Multipotent Stem Cells ◽  
Calcium Dependent ◽  
Developmental Physiology ◽  
Pattern Determination

Nematocysts are the nonliving secretions of specialized cells, the nematocytes, which develop from multipotent stem cells. Nematocysts are the means by which coelenterates capture prey and defend against predation. The 25 or more known types of nematocysts can be divided into to four functional categories: those that pierce, ensnare, or adhere to prey, and those that adhere to the substrate. During development a collagenous cyst, which may contain toxins, forms; a hollow thread, which becomes coiled as it invaginates, develops. Maturing nematocyte–nematocyst complexes migrate to their discharge sites and are deployed in specific patterns. The mechanisms of pattern determination are not clear. Discharge of nematocysts appears to involve increases in intracapsular osmotic pressure consequent upon release of bound calcium within the capsule; the eversion of the filament may depend upon release of structural tension consequent upon a loss of zinc from the thread. Evidence exists that discharge is initiated as a calcium-dependent exocytosis, triggered by an electrical signal resulting from the transduction of mechanical stimuli received at the nematocyte's cnidocil. Chemical signals transduced in adjacent sensory cells alter the frequency response of the nematocyte. In opposition to the nematocyte–nematocyst independent effector hypothesis, excitatory and inhibitory neuronal input appears to regulate discharge.

Effects of Matrix Stiffness on the Differentiation of Multipotent Stem Cells

2020 ◽  
Vol 15 (5) ◽  
pp. 449-461 ◽  
Author(s):  
Weidong Zhang ◽  
Genglei Chu ◽  
Huan Wang ◽  
Song Chen ◽  
Bin Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Differentiation ◽  
Three Dimensional ◽  
Stem Cell Differentiation ◽  
The Body ◽  
Mechanical Stimuli ◽  
Matrix Stiffness ◽  
Multipotent Stem Cells ◽  
3D Environments ◽  
Mechanical Factors

Differentiation of stem cells, a crucial step in the process of tissue development, repair and regeneration, can be regulated by a variety of mechanical factors such as the stiffness of extracellular matrix. In this review article, the effects of stiffness on the differentiation of stem cells, including bone marrow-derived stem cells, adipose-derived stem cells and neural stem cells, are briefly summarized. Compared to two-dimensional (2D) surfaces, three-dimensional (3D) hydrogel systems better resemble the native environment in the body. Hence, the studies which explore the effects of stiffness on stem cell differentiation in 3D environments are specifically introduced. Integrin is a well-known transmembrane molecule, which plays an important role in the mechanotransduction process. In this review, several integrin-associated signaling molecules, including caveolin, piezo and Yes-associated protein (YAP), are also introduced. In addition, as stiffness-mediated cell differentiation may be affected by other factors, the combined effects of matrix stiffness and viscoelasticity, surface topography, chemical composition, and external mechanical stimuli on cell differentiation are also summarized.

scholarly journals The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

2021 ◽  
Vol 22 (5) ◽  
pp. 2472
Author(s):  
Carl Randall Harrell ◽  
Valentin Djonov ◽  
Vladislav Volarevic
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Immune Cells ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Multipotent Stem Cells ◽  
Tissue Repair And Regeneration ◽  
Almost All ◽  
And Function

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

scholarly journals EZH2 reduction is an essential mechanoresponse for the maintenance of super-enhancer polarization against compressive stress in human periodontal ligament stem cells

2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Qian Li ◽  
Xiwen Sun ◽  
Yunyi Tang ◽  
Yanan Qu ◽  
Yanheng Zhou ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mechanical Stress ◽  
Periodontal Ligament ◽  
Compressive Force ◽  
Mechanical Stimuli ◽  
Periodontal Ligament Stem Cells ◽  
Super Enhancer ◽  
Ezh2 Expression ◽  
A Genome ◽  
Temporal Dimensions

Abstract Despite the ubiquitous mechanical cues at both spatial and temporal dimensions, cell identities and functions are largely immune to the everchanging mechanical stimuli. To understand the molecular basis of this epigenetic stability, we interrogated compressive force-elicited transcriptomic changes in mesenchymal stem cells purified from human periodontal ligament (PDLSCs), and identified H3K27me3 and E2F signatures populated within upregulated and weakly downregulated genes, respectively. Consistently, expressions of several E2F family transcription factors and EZH2, as core methyltransferase for H3K27me3, decreased in response to mechanical stress, which were attributed to force-induced redistribution of RB from nucleoplasm to lamina. Importantly, although epigenomic analysis on H3K27me3 landscape only demonstrated correlating changes at one group of mechanoresponsive genes, we observed a genome-wide destabilization of super-enhancers along with aberrant EZH2 retention. These super-enhancers were tightly bounded by H3K27me3 domain on one side and exhibited attenuating H3K27ac deposition and flattening H3K27ac peaks along with compensated EZH2 expression after force exposure, analogous to increased H3K27ac entropy or decreased H3K27ac polarization. Interference of force-induced EZH2 reduction could drive actin filaments dependent spatial overlap between EZH2 and super-enhancers and functionally compromise the multipotency of PDLSC following mechanical stress. These findings together unveil a specific contribution of EZH2 reduction for the maintenance of super-enhancer stability and cell identity in mechanoresponse.

scholarly journals The Role of the Bone Marrow Microenvironment in the Response to Infection

2020 ◽  
Vol 11 ◽  
Author(s):  
Courtney B. Johnson ◽  
Jizhou Zhang ◽  
Daniel Lucas
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Immune Cells ◽  
Critical Role ◽  
Primary Source ◽  
Bone Marrow Microenvironment ◽  
Future Research ◽  
Multipotent Stem Cells ◽  
Hematopoietic Stem

Hematopoiesis in the bone marrow (BM) is the primary source of immune cells. Hematopoiesis is regulated by a diverse cellular microenvironment that supports stepwise differentiation of multipotent stem cells and progenitors into mature blood cells. Blood cell production is not static and the bone marrow has evolved to sense and respond to infection by rapidly generating immune cells that are quickly released into the circulation to replenish those that are consumed in the periphery. Unfortunately, infection also has deleterious effects injuring hematopoietic stem cells (HSC), inefficient hematopoiesis, and remodeling and destruction of the microenvironment. Despite its central role in immunity, the role of the microenvironment in the response to infection has not been systematically investigated. Here we summarize the key experimental evidence demonstrating a critical role of the bone marrow microenvironment in orchestrating the bone marrow response to infection and discuss areas of future research.

Comparison of human post-embryonic, multipotent stem cells derived from various tissues

2009 ◽  
Vol 31 (7) ◽  
pp. 929-938 ◽  
Author(s):  
Baijun Fang ◽  
Ning Li ◽  
Yongping Song ◽  
Quande Lin ◽  
Robert Chunhua Zhao
Keyword(s):  
Stem Cells ◽  
Multipotent Stem Cells

Biomaterials Nano Geometry for Control of Stem Cell Differentiation

2009 ◽  
Vol 1239 ◽  
Author(s):  
Karla Brammer ◽  
Seunghan Oh ◽  
Sungho Jin
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Stem Cell Differentiation ◽  
Human Mesenchymal Stem Cell ◽  
Oxide Surface ◽  
Specific Cell ◽  
Implant Surface ◽  
Multipotent Stem Cells

AbstractTwo important goals in stem cell research are to control the cell proliferation without differentiation, and also to direct the differentiation into a specific cell lineage when desired. Recent studies indicate that the nanostructures substantially influence the stem cell behavior. It is well known that mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into stromal lineages such as adipocyte, chondrocyte, fibroblast, myocyte, and osteoblast cell types. By examining the cellular behavior of MSCs cultured in vitro on nanostructures, some understanding of the effects that the nanostructures have on the stem cell’s response has been obtained. Here we demonstrate that TiO2 nanotubes produced by anodization on Ti implant surface can regulate human mesenchymal stem cell (hMSC) differentiation towards an osteoblast lineage in the absence of osteogenic inducing factors. Altering the dimensions of nanotubular-shaped titanium oxide surface structures independently allowed either augmented human mesenchymal stem cell (hMSC) adhesion at smaller diameter levels or a specific differentiation of hMSCs into osteoblasts using only the geometric cues. Small (˜30 nm diameter) nanotubes promoted adhesion without noticeable differentiation, while larger (˜70 - 100 nm diameter) nanotubes elicited a dramatic, ˜10 fold stem cell elongation, which induced cytoskeletal stress and selective differentiation into osteoblast-like cells, offering a promising nanotechnology-based route for novel orthopaedics-related hMSC treatments. The fact that a guided and preferential osteogenic differentiation of stem cells can be achieved using substrate nanotopography alone without using potentially toxic, differentiation-inducing chemical agents is significant, which can be useful for future development of novel and enhanced stem cell control and therapeutic implant development.

Migration of Human Mesenchymal Stem Cells is Stimulated by Low Shear Stress via MAPK Signaling

2012 ◽  
Author(s):  
Lin Yuan ◽  
Naoya Sakamoto ◽  
Guanbin Song ◽  
Masaaki Sato
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Human Mesenchymal Stem Cells ◽  
Mapk Signaling ◽  
Disease Treatment ◽  
Differentiation Potential ◽  
Multipotent Stem Cells ◽  
Low Shear Stress ◽  
Multipotent Differentiation ◽  
And Migration

Mesenchymal stem cells (MSCs) represent as multipotent stem cells which hold the abilities of self-renewal and give rise to cells of diverse lineages [1]. With their remarkable combination of multipotent differentiation potential and low immunogenicity, MSCs are considered to be an attractive candidate for cell-based tissue repair and regenerative tissue engineering [2, 3]. Increasing number of studies has demonstrated that mobilization and migration of injected MSCs to the damaged tissues is a key step for these cells to participate in disease treatment and tissue regeneration [4, 5].

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