Name: how embryonic stem cells become specialized
Uploaded: 2019-03-11T09:21:21.000Z
Duration: 58 s
Channel: JoVE

- Les cellules souches embryonnaires, ou cellules ES,sont des cellules indifférenciéesqui viennent de la masse cellulaire interne d'un blastocyte,un embryon de 3 à 5 jours. 
Ils sont pluripotents, ce qui signifiequ'ils peuvent produire tous les types de cellule du corps,des cellules sanguines aux cellules du cerveau,ce qui leur donne une grande diversité d'usages potentielsen sciences et en médecine. 
Ils sont prélevés et cultivés en laboratoire,où ils peuvent se diviser à l'infini,produisant de nouvelles cellules souches. 
En manipulant les conditions de culture,par exemple en ajoutant certains facteurs de croissance,on peut les pousser à se différencieren un type de cellule précis. 
Ces nouvelles cellules peuvent être utiliséespour en remplacer d'autres, dans le corps,perdues à cause de dégâts ou d'une maladie,comme les cellules produisant l'insuline dans le pancréaset qui sont détruites dans le diabète de type 1.

Ilic, Dusko et Caroline Ogilvie. « Revue concise : Cellules souches embryonnaires humaines – Qu’avons-nous fait ? Que faisons-nous ? Où allons-nous ? CELLULES SOUCHES 35, n° 1 (2017) : 17-25. [<a href="https://doi.org/10.1002/stem.2450 » target="__blank">Source</a>]

cellules souches embryonnaires

Embryonic Stem Cells

Les cellules souches embryonnaires (ES) sont des cellules pluripotentes indifférenciées, ce qui signifie qu’elles peuvent produire n’importe quel type de cellule dans le corps. Cela leur donne un potentiel énorme en science et en médecine car elles peuvent générer des types précis de cellules qui sont utilisées dans la recherche ou pour remplacer les cellules du corps perdues à cause de dommages ou de la maladie.
 
 <h4>L’origine</h4>
 
 Les cellules ES sont présentes dans la masse cellulaire interne d’un embryon au stade blastocyste, qui se produit environ 3 à 5 jours après la fécondation chez l’homme avant que l’embryon ne soit implanté dans l’utérus. Les cellules ES humaines sont habituellement dérivées d’embryons donnés restant du processus de fécondation in vitro (FIV).
 
 Les cellules sont recueillies et mises en culture, où elles peuvent se diviser indéfiniment, créant des lignées cellulaires ES Dans certaines conditions, les cellules ES peuvent se différencier, soit spontanément en une variété de types de cellules, soit de manière dirigée pour produire les types de cellules souhaités. Les scientifiques peuvent contrôler quels types de cellules sont générés en manipulant les conditions de culture, comme en changeant la surface de la boite de culture ou en ajoutant des facteurs de croissance spécifiques au milieu de culture, ainsi qu’en modifiant génétiquement les cellules. Grâce à ces méthodes, les chercheurs ont été en mesure de générer de nombreux types de cellules spécifiques à partir de cellules ES, y compris des cellules du sang, de nerf, du cœur, des os, du foie et du pancréas.
 
 <h4>Médecine régénératrice</h4>
 
 La médecine régénératrice concerne la création de tissus vivants et fonctionnels pour remplacer les tissus morts, malades ou défectueux. Compte tenu de leur capacité à se différencier en n’importe quel type de cellule, les cellules ES sont utilisées en médecine régénératrice. Bien que ce domaine en soit encore aux premiers stades, plusieurs types de cellules potentiellement bénéfiques ont été produits à partir de cellules ES, et des études cliniques ont commencé à tester leur innocuité et leur efficacité chez les patients. Certains premiers résultats ont été prometteurs ; par exemple, les patients paralysés ont regagné certains mouvements après avoir reçu des cellules du système nerveux dérivées d’ES. En outre, les cellules ES peuvent être utilisées pour étudier les premiers événements dans le développement humain, ce qui est difficile autrement, et fournissent une source de types de cellules spécifiques qui peuvent être utilisés dans l’évaluation des médicaments et d’autres recherches scientifiques.

Cellules souches embryonnaires

Les cellules souches embryonnaires (SE) sont des cellules pluripotentes indifférenciées, ce qui signifie qu’elles peuvent produire n’importe quel type de cellule dans le corps. Cela leur donne un potentiel énorme...

Education

Enseignement

JoVE Core

Biology

Biologie

Genetics

Génétique

Biotechnology

Biotechnologie

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

how embryonic stem cells become specialized

Embryonic stem cells are pluripotent cells that have not yet specialized. Pluripotent means they can give rise to many different cell types in the body. Because of this, they are useful in science and medicine for making cells needed in research or for replacing cells lost to damage or disease.

These cells come from the inner cell mass of a blastocyst, which is an early embryo about 3 to 5 days after fertilization in humans. At this stage, the embryo has not yet implanted in the uterus. Human embryonic stem cells are usually taken from donated embryos left over from in vitro fertilization, or IVF.

Once collected, the cells are grown in culture and can divide for a very long time. This creates embryonic stem cell lines. Under the right conditions, the cells can differentiate, which means they can become specialized cells. They may do this on their own or through directed differentiation into a chosen cell type.

Scientists guide this process by changing the culture conditions. They may alter the surface of the culture dish, add specific growth factors to the medium, or genetically modify the cells. Using these methods, researchers have made blood, nerve, heart, bone, liver, and pancreas cells from embryonic stem cells.

These cells also have an important role in regenerative medicine, which aims to create living, functional tissues to replace dead, diseased, or malfunctioning ones. This field is still in early stages, but some cell types made from embryonic stem cells have already been tested in clinical studies. Some results have been promising, including reports of paralyzed patients regaining some movement after receiving nervous system cells made from embryonic stem cells. Researchers also use these cells to study early human development and to provide specific cell types for drug testing and other scientific research.

How Embryonic Stem Cells Become Specialized

how-embryonic-stem-cells-become-specialized

what is genetic engineering?

How Scientists Edit DNA for New Traits

Genetic engineering changes an organism’s DNA to add useful traits. Scientists use it in bacteria, plants, animals, and even viruses for research, medicine, agriculture, and industry. It can bring major benefits, but it also raises ethical concerns about humans and the food supply. This work is possible because DNA has the same basic structure and genetic code across life. That shared code lets scientists modify DNA in several ways. One method is CRISPR/Cas9, often called molecular scissors,...

dna isolation

Steps in DNA Extraction

DNA extraction is the process of removing and purifying DNA from cells. It is used in many biotechnology and research applications, including molecular cloning. The main goal is to free DNA from the cell and prepare it for later study or use. The first step is cell lysis, which means breaking cells open. Researchers may use a homogenizer, sonicator, or bead beater to physically lyse the cells. They also often add detergent to chemically disrupt the lipid-based cell membranes. This helps...

recombinant dna technology

Recombinant DNA in Cloning and GMOs

Recombinant DNA is made by joining DNA from different sources in the lab. Scientists often use it to clone genes and study them in cells that are easy to handle, such as bacteria. Organisms that carry recombinant DNA are called genetically modified organisms, or GMOs. This technology gives scientists new tools for research, medicine, and agriculture. To build recombinant DNA, researchers place a gene of interest into a vector, which is a DNA carrier that moves foreign DNA into a host cell. The...

PCR Cycle for DNA Amplification

PCR is a laboratory method for making many copies of a DNA segment. It can turn a small amount of DNA into millions or even billions of copies in just a few hours. The process uses a heat-resistant DNA polymerase inside a machine called a thermocycler. PCR was developed by Kary Mullis in 1983, and he received the 1993 Nobel Prize in Chemistry for it. The method is fast, relatively inexpensive, and precise. It has become useful for molecular cloning, gene mutagenesis, pathogen detection, gene...

complementary dna

From mRNA to cDNA for Gene Studies

Complementary DNA, or cDNA, is made from messenger RNA (mRNA) so scientists can study which genes are active in cells and tissues. Only genes that are transcribed into mRNA are expressed. By extracting mRNA from cells, researchers can compare gene expression across samples. cDNA is produced by reverse transcription. This process copies mRNA into DNA, which is useful because mRNA does not contain introns, or non-coding regions, and other regulatory sequences. As a result, cDNA can help...

antibiotic selection

Antibiotic Resistance in Cloning

Antibiotic resistance genes help scientists find bacteria that took up a plasmid with a gene of interest. In genetic engineering, this resistance is used as a marker, not just as a medical concern. The same process also connects to the growing problem of resistant bacteria in the real world. Antibiotics, such as penicillin, stop bacterial growth or kill bacteria. When bacteria naturally have, or are engineered to carry, an antibiotic resistance gene, the antibiotic no longer works on them.

transgenic organisms

Creating Transgenic Plants and Animals

Transgenic organisms are genetically engineered to carry a transgene, which is a gene from a different species, in their genome. The inserted gene may be a new gene for that organism or a different version of one it already has. Scientists usually make transgenes with recombinant DNA and DNA cloning methods. Researchers use transgenic bacteria, plants, and animals to answer biological questions and to build useful tools. To make a transgenic organism, they first choose a transgenesis method,...

in-vitro mutagenesis (gene knockouts)

Knockout Mice and Gene Replacement

Knockout mice help researchers study gene function by showing what happens when a gene is turned off. These engineered animals are also useful for modeling human diseases such as cancer, Parkinson’s disease, and diabetes. A specific gene can be targeted by using a targeting vector, which is a piece of engineered DNA that replaces the normal gene and inactivates it. The vector has matching DNA sequences on both ends. These homologous sequences let the vector swap in for the target gene through...

crispr

CRISPR-Cas9 Gene Editing in Action

CRISPR-Cas9 is a genome editing tool that lets scientists change DNA at a specific location. It can add, remove, or rearrange genetic material. Researchers study it because it may help treat genetic disorders such as hemophilia and sickle cell anemia. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and Cas9 is a CRISPR-associated protein 9. The basic system includes a Cas9 endonuclease, which is an enzyme that cuts DNA, and a small RNA that guides Cas9 to the...

gene therapy

Gene Delivery for Serious Diseases

Gene therapy is a technique used to treat serious disease by adding a gene to a person’s cells. The added gene may be a healthy copy of a mutated gene. It may also be a different gene that inactivates or compensates for the disease-causing gene. One example is severe combined immunodeficiency, or SCID, caused by a mutation in the gene for adenosine deaminase. In that case, a working copy of the gene can be inserted so the patient’s cells make the enzyme again. This can cure the disease in some...

embryonic stem cells

Embryonic stem cells are pluripotent cells that have not yet specialized. Pluripotent means they can give rise to many different cell types in the body. Because of this, they are useful in science and medicine for making cells needed in research or for replacing cells lost to damage or disease. These cells come from the inner cell mass of a blastocyst, which is an early embryo about 3 to 5 days after fertilization in humans. At this stage, the embryo has not yet implanted in the uterus. Human...

adult stem cells

Adult Stem Cells in the Small Intestine

Adult stem cells help maintain tissues by replacing old or damaged cells. These undifferentiated cells divide to make more stem cells or progenitor cells, which then become mature, specialized cells. Small groups of adult stem cells are found in many tissues, including the bone marrow, brain, skin, and gut. The small intestine shows this process clearly. Its lining, called the epithelium, is renewed continuously by adult stem cells. It is also the fastest replaced tissue in the human body,...

induced pluripotent stem cells

Reprogramming Mature Cells into Stem Cells

Reprogramming mature cells into stem cells lets scientists turn specialized cells back into an unspecialized state. These cells are called induced pluripotent stem cells, or iPSCs. Like embryonic stem cells, iPSCs are pluripotent, which means they can form all cell types. To make iPSCs, researchers start with mature cells such as skin fibroblasts or blood cells. The cells are grown in culture, and genes for several transcription factors are delivered with a viral vector. The cells then make...

reproductive cloning

Cloning Animals with SCNT

Reproductive cloning can produce a genetically identical copy of an entire organism. In adult animals, this is usually done with somatic cell nuclear transfer, or SCNT. Another way clones can form is by splitting an early embryo, which is similar to how identical twins arise naturally. In SCNT, an egg cell is taken from an animal and its nucleus is removed. This creates an enucleated egg. A somatic cell, which is any body cell that is not a sex cell, is then taken from the animal to be cloned.

genomics

Genomics and DNA Sequencing

Genomics studies the full set of genetic material in an organism. In humans, that genome includes the DNA carried in 23 pairs of chromosomes in the nucleus, along with mitochondrial DNA. Genomics looks at both coding DNA and non-coding DNA, which helps scientists study how living things are built and how they differ. This field is useful in many areas of biology and medicine. Scientists use genomics to build phylogenetic trees, improve crop productivity and sustainability, help with criminal...

key terms and concepts

Explore how embryonic stem cells are grown, guided to specialize, and used in regenerative medicine, development studies, and drug testing.

How Embryonic Stem Cells Become Specialized | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

La collection JoVE Core Biologie donne vie à la biologie à travers plus de 300 leçons vidéos animées concises et faciles à comprendre qui expliquent les concept clés de la biologie, mais aussi plus de 150 vidéos de scientifiques à l'action effectuant des expériences de recherche dans des laboratoires modernes.

myJoVE Corporation

How Embryonic Stem Cells Become Specialized

Description

Transcript

Tags