Integrins and human intestinal cell functions

1999 ◽  
Vol 4 (1-3) ◽  
pp. d310 ◽  
Author(s):  
Jean-Francois Beaulieu
Keyword(s):  
Intestinal Cell ◽  
Cell Functions

scholarly journals Signaling pathways in intestinal homeostasis and colorectal cancer: KRAS at centre stage

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Camille Ternet ◽  
Christina Kiel
Keyword(s):  
Colorectal Cancer ◽  
Signaling Pathways ◽  
Intestinal Microbiota ◽  
Critical Role ◽  
Neuroendocrine Cells ◽  
Cell Junction ◽  
Intestinal Cell ◽  
Intestinal Homeostasis ◽  
Cell Functions ◽  
The Impact

AbstractThe intestinal epithelium acts as a physical barrier that separates the intestinal microbiota from the host and is critical for preserving intestinal homeostasis. The barrier is formed by tightly linked intestinal epithelial cells (IECs) (i.e. enterocytes, goblet cells, neuroendocrine cells, tuft cells, Paneth cells, and M cells), which constantly self-renew and shed. IECs also communicate with microbiota, coordinate innate and adaptive effector cell functions. In this review, we summarize the signaling pathways contributing to intestinal cell fates and homeostasis functions. We focus especially on intestinal stem cell proliferation, cell junction formation, remodelling, hypoxia, the impact of intestinal microbiota, the immune system, inflammation, and metabolism. Recognizing the critical role of KRAS mutants in colorectal cancer, we highlight the connections of KRAS signaling pathways in coordinating these functions. Furthermore, we review the impact of KRAS colorectal cancer mutants on pathway rewiring associated with disruption and dysfunction of the normal intestinal homeostasis. Given that KRAS is still considered undruggable and the development of treatments that directly target KRAS are unlikely, we discuss the suitability of targeting pathways downstream of KRAS as well as alterations of cell extrinsic/microenvironmental factors as possible targets for modulating signaling pathways in colorectal cancer.

Integrins and human intestinal cell functions

10.2741/a429 ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. d310-321 ◽  
Author(s):  
Jean-François Beaulieu
Keyword(s):  
Intestinal Cell ◽  
Cell Functions

Interactions between laminin and epithelial cells in intestinal health and disease

2001 ◽  
Vol 3 (24) ◽  
pp. 1-18 ◽  
Author(s):  
Inga C. Teller ◽  
Jean-François Beaulieu
Keyword(s):  
Biological Activities ◽  
Basement Membranes ◽  
Intestinal Cell ◽  
Specific Cell ◽  
Intestinal Health ◽  
In Vivo Models ◽  
Cell Functions ◽  
Cell Adhesion And Migration

Laminins are a multigene family of extracellular matrix molecules. Quantitatively, they are one of the most abundant glycoproteins present in basement membranes. Functionally, they can modulate several key biological activities, including cell adhesion and migration, gene expression and cell survival. Variability in the spatial and temporal expression of laminins, as well as of their specific receptors of the integrin family, in various tissues and organs, suggests that different laminins perform distinct functions. This article focuses on the human intestinal epithelium as a paradigm to illustrate the potential relationship between laminin–cell interactions and the cell state. This rapidly renewing epithelium consists of spatially separated proliferative and differentiated cell populations located in the crypts and on the villi, respectively. Differential distributions of the various laminins and laminin-binding integrins have been observed along the crypt–villus axis in both the developing and the adult intestine, and important alterations in the pattern of laminin expression have been reported in various intestinal pathologies, such as tufting enteropathy, Crohn's disease and ulcerative colitis, and colorectal cancer. More-direct approaches, including experimentation with in vitro and in vivo models, have provided evidence in support of a role for laminins in intestinal cell functions. Although further work is still needed, laminins emerge more and more as key regulators of specific cell functions important in both intestinal health and intestinal disease.

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

Multimode light microscopy and fluorescence-based reagents as tools for the study of chemical and molecular dynamics of living cells and tissues

1992 ◽  
Vol 50 (1) ◽  
pp. 418-419
Author(s):  
D. L. Taylor
Keyword(s):  
Living Cells ◽  
Cellular Level ◽  
Molecular Techniques ◽  
Cellular Functions ◽  
Macromolecular Assemblies ◽  
Cell Functions ◽  
Molecular Events ◽  
Yield Information ◽  
Full Knowledge ◽  
Structural Methods

Cells function through the complex temporal and spatial interplay of ions, metabolites, macromolecules and macromolecular assemblies. Biochemical approaches allow the investigator to define the components and the solution chemical reactions that might be involved in cellular functions. Static structural methods can yield information concerning the 2- and 3-D organization of known and unknown cellular constituents. Genetic and molecular techniques are powerful approaches that can alter specific functions through the manipulation of gene products and thus identify necessary components and sequences of molecular events. However, full knowledge of the mechanism of particular cell functions will require direct measurement of the interplay of cellular constituents. Therefore, there has been a need to develop methods that can yield chemical and molecular information in time and space in living cells, while allowing the integration of information from biochemical, molecular and genetic approaches at the cellular level.

The photoreceptor cytoskeleton visualized

1992 ◽  
Vol 50 (1) ◽  
pp. 480-481
Author(s):  
Beth Burnside
Keyword(s):  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Polarization ◽  
Synaptic Proteins ◽  
Cell Functions ◽  
Vertebrate Photoreceptor ◽  
Numerous Cell ◽  
Turn Over

The vertebrate photoreceptor provides a drammatic example of cell polarization. Specialized to carry out phototransduction at its distal end and to synapse with retinal interneurons at its proximal end, this long slender cell has a uniquely polarized morphology which is reflected in a similarly polarized cytoskeleton. Membranes bearing photopigment are localized in the outer segment, a modified sensory cilium. Sodium pumps which maintain the dark current critical to photosensory transduction are anchored along the inner segment plasma membrane between the outer segment and the nucleus.Proximal to the nucleus is a slender axon terminating in specialized invaginating synapses with other neurons of the retina. Though photoreceptor diameter is only 3-8u, its length from the tip of the outer segment to the synapse may be as great as 200μ. This peculiar linear cell morphology poses special logistical problems and has evoked interesting solutions for numerous cell functions. For example, the outer segment membranes turn over by means of a unique mechanism in which new disks are continuously added at the proximal base of the outer segment, while effete disks are discarded at the tip and phagocytosed by the retinal pigment epithelium. Outer segment proteins are synthesized in the Golgi near the nucleus and must be transported north through the inner segment to their sites of assembly into the outer segment, while synaptic proteins must be transported south through the axon to the synapse.The role of the cytoskeleton in photoreceptor motile processes is being intensely investigated in several laboratories.

Cyste(i)ne stimulates intestinal cell proliferation independent of glutathione synthesis

2001 ◽  
Vol 120 (5) ◽  
pp. A502-A502
Author(s):  
T NODA ◽  
R IWAKIRI ◽  
K FUJIMOTO ◽  
T AW
Keyword(s):  
Cell Proliferation ◽  
Intestinal Cell ◽  
Glutathione Synthesis

Defibrotide Inhibits Platelet Activation by Cathepsin G Released From Stimulated Polymorphonuclear Leukocytes

1992 ◽  
Vol 67 (06) ◽  
pp. 660-664 ◽  
Author(s):  
Virgilio Evangelista ◽  
Paola Piccardoni ◽  
Giovanni de Gaetano ◽  
Chiara Cerletti
Keyword(s):  
Platelet Activation ◽  
Polymorphonuclear Leukocytes ◽  
Direct Interaction ◽  
Cathepsin G ◽  
In Vivo Test ◽  
Cell Functions ◽  
Test Models ◽  
Antithrombotic Effects

SummaryDefibrotide is a polydeoxyribonucleotide with antithrombotic effects in experimental animal models. Most of the actions of this drug have been observed in in vivo test models but no effects have been reported in in vitro systems. In this paper we demonstrate that defibrotide interferes with polymorphonuclear leukocyte-induced human platelet activation in vitro. This effect was not related to any direct interaction with polymorphonuclear leukocytes or platelets, but was due to the inhibition of cathepsin G, the main biochemical mediator of this cell-cell cooperation. Since cathepsin G not only induces platelet activation but also affects some endothelial cell functions, the anticathepsin G activity of defibrotide could help to explain the antithrombotic effect of this drug.

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