Name: reprogramming mature cells into stem cells
Uploaded: 2019-03-11T09:21:22.000Z
Duration: 1 min 13 s
Channel: JoVE

- [Narratore] Le cellule staminali
pluripotenti indotte,iPSC

sono cellule mature e
differenziate come le cellule della

pelle che vengono riprogrammate
in laboratorio per essere

simili alle cellule staminali
embrionali indifferenziate.

Cioè, si dividono e
sono pluripotenti, sono

in grado di produrre qualsiasi
tipo di cellula nel corpo.

Ad esempio, le cellule
retiniche che potrebbero essere

utilizzate per sostituire il
tessuto retinico danneggiato.

Per creare iPSC, cellule mature
come fibroblasti della pelle

sono presi da un paziente
e messi in coltura.

Quindi, in genere, i geni
per i fattori di trascrizione

sono consegnati da vettori
virali nei nuclei delle cellule

dove sono incorporati nel genoma.

I fattori di trascrizione
attivano quindi i geni

che sono espressi da
cellule staminali embrionali

de-differenziandoli in modo efficace

e portandoli a uno stato pluripotente.

Le cellule possono ora dividersi
e idealmente essere dirette

per produrre un tipo specifico
di cellule in coltura.

Le nuove cellule potrebbero
quindi essere trapiantate

di nuovo nel paziente per
curare il danno o la malattia

con il minimo rischio di rigetto

perché provenienti dalle
cellule del paziente stesso.

Hamazaki, Takashi, Nihal El Rouby, Natalie C. Fredette, Katherine E. Santostefano e Naohiro Terada. "Revisione concisa: ricerca indotta sulle cellule staminali pluripotenti nell'era della medicina di precisione". Cellule staminali (Dayton, Ohio) 35, n. 3 (marzo 2017): 545–50. [<a href="https://doi.org/10.1002/stem.2570" target="__blank">Source</a>].

induced pluripotent stem cells

Induced Pluripotent Stem Cells

Le cellule staminali sono cellule indifferenziate che dividono e producono diversi tipi di cellule. In genere, le celle differenziate in un tipo di cella specifico sono post-mitotiche, ovvero non si dividono più. Tuttavia, gli scienziati hanno trovato un modo per riprogrammare queste cellule mature in modo che "de-differenzino" e tornino a uno stato non specializzato e proliferino. Queste cellule sono anche pluripotenti come cellule staminali embrionali, in grado di produrre tutti i tipi di cellule, e sono quindi chiamate cellule staminali pluripotenti indotte (iPSC).

Gli iPSC sono potenzialmente preziosi in medicina, perché un paziente che ha bisogno di un particolare tipo di cellula, ad esempio una retina danneggiata a causa della degenerazione maculare, potrebbe ricevere un trapianto delle cellule richieste, generato da un altro tipo di cellula nel proprio corpo. Questo è chiamato trapianto autologo, e riduce il rischio di rigetto del trapianto che può verificarsi quando i tessuti vengono trapiantati tra individui.

<h4>Il processo</h4>

Per creare iPSC, le cellule mature come i fibroblasti della pelle o le cellule del sangue di una persona sono coltivate in coltura. Quindi, i geni per più fattori di trascrizione vengono consegnati nelle cellule utilizzando un vettore virale, e le proteine del fattore di trascrizione vengono espresse utilizzando il meccanismo della cellula. I fattori di trascrizione si attivano poi molti altri geni che sono espressi da cellule staminali embrionali, restituendo le cellule a uno stato indifferenziato, proliferante e pluripotente.

È ancora in fase di studio se gli iPSC siano realmente equivalenti alle cellule staminali embrionali, ma sembrano essere simili e possono produrre cellule da tutti e tre gli strati germinali del corpo. Come per altri tipi di cellule staminali, gli scienziati stanno imparando a promuovere la differenziazione di specifici tipi di cellule dagli iPSC in modo efficiente, in modo che i tipi di cellule necessari possano essere prodotti in quantità adeguate.

<h4>Prime sperimentazioni cliniche</h4>

Le prime cellule retiniche trapiantate in studio clinico derivate da iPSC in pazienti con degenerazione maculare senile. Da allora, diversi studi clinici iPSC sono stati approvati per il trattamento del morbo di Parkinson, malattia cardiaca, e lesioni del midollo spinale. Le cellule prelevate dai pazienti e trasformate in iPSC vengono utilizzate anche per studiare le loro malattie in laboratorio. In generale, gli iPSC forniscono un'altra fonte di cellule staminali per la ricerca scientifica.

Stem cells are undifferentiated cells that divide and produce different types of cells. Ordinarily, cells that have differentiated into a specific cell ...

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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 those transcription factor proteins, which switch on other genes that are active in embryonic stem cells and return the cells to a proliferative, undifferentiated, and pluripotent state.

iPSCs may be useful in medicine because they can come from a patient’s own body. For example, cells needed to repair a damaged retina in age-related macular degeneration could be made from that same patient’s cells. This autologous transplantation lowers the risk of transplant rejection that can happen when tissue is moved between different people.

Scientists are still studying whether iPSCs are truly equivalent to embryonic stem cells, but they appear to be similar and can produce cells from all three germ layers. Researchers are also working on ways to direct iPSCs to become specific cell types in efficient amounts. Early clinical trials have used iPSC-derived retinal cells for macular degeneration, and other trials have been approved for Parkinson’s disease, heart disease, and spinal cord injury. Patient cells turned into iPSCs are also helping scientists study disease in the lab.

Reprogramming Mature Cells into Stem Cells

reprogramming-mature-cells-into-stem-cells

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

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...

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,...

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

Learn how mature cells are reprogrammed into induced pluripotent stem cells, why iPSCs matter for transplants, and how they are used in research and clinical trials.

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Reprogramming Mature Cells into Stem Cells

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