In genetics and developmental biology, somatic cell nuclear transfer (SCNT) is a laboratory strategy for creating a viable embryo from a body cell and an egg cell. The technique consists of taking an enucleated oocyte (egg cell) and implanting a donor nucleus from a somatic (body) cell. It is used in both therapeutic and reproductive cloning. Dolly the Sheep became famous for being the first successful case of the reproductive cloning of a mammal. "Therapeutic cloning" refers to the potential use of SCNT in regenerative medicine; this approach has been championed as an answer to the many issues concerning embryonic stem cells (ESC) and the destruction of viable embryos for medical use, though questions remain on how homologous the two cell types truly are.
The process of somatic cell nuclear transplant involves two different cells. The first being a female gamete, known as the ovum (egg/oocyte). In human SCNT experiments, these eggs are obtained through consenting donors, many times utilizing ovarian stimulation. The second being a somatic cell, referring to the cells of the human body. Skin cells, fat cells, and liver cells are only a few examples. The nucleus of the donor egg cell is removed and discarded, leaving it 'deprogrammed.' The nucleus of the somatic cell is also removed but is kept, the enucleated somatic cell is discarded. What is left is a lone somatic nucleus and an enucleated egg cell. These are then fused by squirting the somatic nucleus into the 'empty' ovum. After being inserted into the egg, the somatic cell nucleus is reprogrammed by its host egg cell. The ovum, now containing the somatic cell's nucleus, is stimulated with a shock and will begin to divide. The egg is now viable and capable of producing an adult organism containing all the necessary genetic information from just one parent. Development will ensue normally and after many mitotic divisions, this single cell forms a blastocyst (an early stage embryo with about 100 cells) with an identical genome to the original organism (i.e. a clone). Stem cells can then be obtained by the destruction of this clone embryo for use in therapeutic cloning or in the case of reproductive cloning the clone embryo is implanted into a host mother for further development and brought to term.
Somatic cell nuclear transplantation has become a focus of study in stem cell research. The aim of carrying out this procedure is to obtain pluripotent cells from a cloned embryo. These cells genetically matched the donor organism from which they came.This gives them the ability to create patient specific pluripotent cells, which could then be used in therapies or disease research.
Embryonic stem cells are undifferentiated cells of an embryo. These cells are deemed to have a pluripotent potential because they have the ability to give rise to all of the tissues found in an adult organism. This ability allows stem cells to create any cell type, which could then be transplanted to replace damaged or destroyed cells. Controversy surrounds human ESC work due to the destruction of viable human embryos. Leading scientists to seek an alternative method of obtaining stem cells, SCNT is one such method.
A potential use of stem cells genetically matched to a patient would be to create cell lines that have genes linked to a patient's particular disease. By doing so, an in vitro model could be created, would be useful for studying that particular disease, potentially discovering its pathophysiology, and discovering therapies. For example, if a person with Parkinson's disease donated his or her somatic cells, the stem cells resulting from SCNT would have genes that contribute to Parkinson's disease. The disease specific stem cell lines could then be studied in order to better understand the condition.
Another application of SCNT stem cell research is using the patient specific stem cell lines to generate tissues or even organs for transplant into the specific patient. The resulting cells would be genetically identical to the somatic cell donor, thus avoiding any complications from immune system rejection.
Only a handful of the labs in the world are currently using SCNT techniques in human stem cell research. In the United States, scientists at the Harvard Stem Cell Institute, the University of California San Francisco, the Oregon Health & Science University,Stemagen (La Jolla, CA) and possibly Advanced Cell Technology are currently researching a technique to use somatic cell nuclear transfer to produce embryonic stem cells. In the United Kingdom, the Human Fertilisation and Embryology Authority has granted permission to research groups at the Roslin Institute and the Newcastle Centre for Life. SCNT may also be occurring in China.
In 2005, a South Korean research team led by Professor Hwang Woo-suk, published claims to have derived stem cell lines via SCNT, but supported those claims with fabricated data. Recent evidence has proved that he in fact created a stem cell line from a parthenote.
Though there has been numerous successes with cloning animals, questions remain concerning the mechanisms of reprogramming in the ovum. Despite many attempts, success in creating human nuclear transfer embryonic stem cells has been limited. There lies a problem in the human cell's ability to form a blastocyst; the cells fail to progress past the eight cell stage of development. This is thought to be a result from the somatic cell nucleus being unable to turn on embryonic genes crucial for proper development. These earlier experiments used procedures developed in non-primate animals with little success. A research group from the Oregon Health & Science University demonstrated SCNT procedures developed for primates successfully reprogrammed skin cells into stem cells. The key to their success was utilizing oocytes in metaphase II (MII) of the cell cycle. Egg cells in MII contain special factors in the cytoplasm that have a special ability in reprogramming implanted somatic cell nuclei into cells with pluripotent states. When the ovum's nucleus is removed, the cell loses its genetic information. This has been blamed for why enucleated eggs are hampered in their reprogramming ability. It is theorized the critical embryonic genes are physically linked to oocyte chromosomes, enucleation negatively affects these factors. Another possibility is removing the egg nucleus or inserting the somatic nucleus causes damage to the cytoplast, affecting reprogramming ability. Taking this into account the research group applied their new technique in an attempt to produce human SCNT stem cells. In May 2013, the Oregon group reported the successful derivation of human embryonic stem cell lines derived through SCNT, using fetal and infant donor cells. Using MII oocytes from volunteers and their improved SCNT procedure, human clone embryos were successfully produced. These embryos were of poor quality, lacking a substantial inner cell mass and poorly constructed trophectoderm. The imperfect embryos prevented the acquisition of human ESC. The addition of caffeine during the removal of the ovum's nucleus and injection of the somatic nucleus improved blastocyst formation and ESC isolation. The ESC obtain were found to be capable of producing teratomas, expressed pluripotent transcription factors, and expressed a normal 46XX karyotype, indicating these SCNT were in fact ESC-like. This was the first instance of successfully using SCNT to reprogram human somatic cells. This study used fetal and infantile somatic cells to produce their ESC.
In April 2014, an international research team expanded on this break through. There remained the question of whether the same success could be accomplished using adult somatic cells. Epigenetic and age related changes were thought to possibly hinder an adult somatic cells ability to be reprogrammed. Implementing the procedure pioneered by the Oregon research group they indeed were able to grow stem cells generated by SCNT using adult cells from two donors, aged 35 and 75.Indicating age does not impede a cells ability to be reprogrammed
- Orgenesis and Theracell to launch point-of-care cell and gene therapy centers in HYGEIA Group"s hospitals - Proactive Investors USA & Canada - December 6th, 2019
- Rocket Pharmaceuticals Announces First Patient Treated in Global Registrational Phase 2 Study of RP-L102 Process B for Fanconi Anemia - BioSpace - December 6th, 2019
- Stem Cell Therapy Industry 2019 Global Market Size, Trends, Revenue, Growth Prospects, Key Companies and Forecast by 2023 - Techi Labs - December 6th, 2019
- Brave new world? Why the public might be ready for gene-edited babies - Genetic Literacy Project - December 6th, 2019
- Stem Cell Therapies Market research to Witness a Healthy Growth during 2015 2025 - Lake Shore Gazette - November 25th, 2019
- Osteonecrosis Treatment Market Benefit and Volume with Status and Prospect to 2026 - Crypto Journal - November 21st, 2019
- US Nobel laureates tell us what they think about cancer research, moonshots, the dark side, funding, meritocracy, herd mentality, Trump, and joy - The... - November 21st, 2019
- Youngstown State, IBM to offer high-tech training in the Mahoning Valley - Crain's Cleveland Business - November 15th, 2019
- A short guide to regulation for disruptive technologies - Lexology - November 14th, 2019
- Cereal rust could lead to new wheat threat - Farm Weekly - November 14th, 2019
- Tooth Regeneration Industry 2019 Research on Market Sales, Revenue, Top Companies and Future Development - TheFinanceTime - November 11th, 2019
- Stem Cell Therapy Market : Opportunities and Challenges - MENAFN.COM - November 3rd, 2019
- Cell Therapy Market Forecast to 2025 | Analysis by Regions, Type, Application, and Top Key Players like Dendreon, Mesoblast, Vericel, Antibe... - November 3rd, 2019
- Detection of Latent HSCs Fated to Progress to Blast Phase in Myelofibrosis Patients Several Years Before Blast Transformation - DocWire News - October 25th, 2019
- Stem cell therapy is for animals too - SciTech Europa - October 21st, 2019
- Stem Cell Therapy Industry 2019 Global Market Size, Trends, Revenue, Growth Prospects, Key Companies and Forecast by 2023 - Markets Gazette - October 17th, 2019
- Significant Growth Foreseen by Stem Cell Therapies Market During 2015 2025 - Rapid News Network - September 22nd, 2019
- Blast Off With Rocket Pharmaceuticals - Seeking Alpha - September 22nd, 2019
- Zinc Finger Nuclease Technology Market Estimated to Discern 2X Expansion by 2025 - Commerce Gazette - September 22nd, 2019
- Tooth Regeneration Market : Huge Growth Opportunity by Trend, Key Players and Forecast 2026 - TodayTimes - September 22nd, 2019
- Direct generation of human naive induced pluripotent stem ... - June 5th, 2019
- Somatic Stem Cells and Cancer - Stem Cell Centers ... - May 4th, 2019
- Difference Between Embryonic and Somatic Stem Cells ... - May 3rd, 2019
- Mosaic (genetics) - Wikipedia - March 8th, 2019
- What is the Difference Between Embryonic and Somatic Stem Cells - February 27th, 2019
- Somatic Cells - Definition and Examples | Biology Dictionary - November 14th, 2018
- Stem Cell Quick Reference - Learn.Genetics - September 9th, 2018
- Where Do Stem Cells Come From? - verywellhealth.com - July 2nd, 2018
- What Is Another Name for Somatic Stem Cells and What Do ... - June 22nd, 2018
- Difference Between Somatic Cells and Gametes ... - June 19th, 2018
- Skin graft gene therapy could treat obesity and diabetes - ResearchGate (blog) - August 3rd, 2017
- Cloning - Wikipedia - December 7th, 2016
- Characterization of Regenerative Phenotype of Unrestricted ... - December 1st, 2016
- Somatic cell nuclear transfer - Wikipedia - November 25th, 2016
- Somatic cell - Wikipedia - November 2nd, 2016
- Embryonic and Somatic Stem Cells, Whats the Difference? - November 2nd, 2016
- Adult stem cell - Wikipedia - October 21st, 2016
- Somatic stem cells in the human endometrium. - October 7th, 2016
- Glossary | stemcells.nih.gov - September 17th, 2016
- Stem Cell Basics IV. | stemcells.nih.gov - September 17th, 2016
- Human embryonic stem cells derived by somatic cell nuclear ... - August 3rd, 2015
- Comparative proteomic analysis of human somatic cells ... - July 20th, 2015
- Somatic cell - Wikipedia, the free encyclopedia - July 15th, 2015
- somatic stem cell - Learn Genetics - July 2nd, 2015
- What is the difference between embryonic and somatic stem ... - June 11th, 2015
- Redox Signaling and Stem Cell Function - Dirk Bohmann - June 2nd, 2015
- Adult stem cell - Wikipedia, the free encyclopedia - June 1st, 2015
- somatic stem cells - Science Daily - May 24th, 2015
- Somatic Cell Nuclear Transfer | Knoepfler Lab Stem Cell Blog - May 20th, 2015
- Adult stem cell - ScienceDaily - May 10th, 2015
- Glossary [Stem Cell Information] - Embryonic stem cell - May 6th, 2015
- Human oocytes reprogram adult somatic nuclei of a type 1 ... - May 6th, 2015