5. Tissue-specific stem cells

2021 ◽  
pp. 75-89
Author(s):  
Jonathan Slack

‘Tissue-specific stem cells’ explores tissue-specific stem cells, which are stem cells found in the postnatal body that are responsible for tissue renewal or for repair following damage. Tissue-specific stem cells share with pluripotent stem cells the same ability to persist indefinitely as a population, to reproduce themselves, and to generate differentiated progeny cells. However, tissue-specific stem cells share few molecular characteristics with embryonic stem (ES) cells or induced pluripotent stem cells (iPS cells), such as expression of specific transcription factors or cell surface molecules. Only renewal tissues have stem cells in the sense of a special population of cells that reproduce themselves and continue to generate differentiated progeny.

2014 ◽  
Vol 8 (1) ◽  
pp. 5-10
Author(s):  
Song Hua ◽  
Henry Chung ◽  
Kuldip Sidhu

AbstractBackground: Therapeutic cloning is the combination of somatic cell nuclear transfer (SCNT) and embryonic stem cell (ES) techniques to create specific ES cells that match those of a patient. Because ES cells derived by nuclear transfer (SCNT ES cells) are genetically identical to the donor, it will not generate rejection by the host’s immune system and thus therapeutically may be more acceptable. Induced pluripotent stem cells (iPS) are a type of pluripotent stem cell artificially derived from an adult somatic cell by inducing a forced expression of a set of specific pluripotent genes. In the past few years, rapid progress in reprogramming and iPS technology has been made, and it seems to shadow any progress made in SCNT programs.Objective: This review compares the application perspective of SCNT with that of iPS in regenerative medicine.Methods:We conducted a literature search using the MEDLINE (PubMed), Wiley InterScience, Springer, EBSCO, and Annual Reviews databases using the keywords “iPS”, “ES”, “SCNT” “induced pluripotent stem cells”, “embryonic stem cells”, “therapeutic cloning”, “regenerative medicine”, and “somatic cell nuclear transfer”. Only articles published in English were included in this review.Results: These two methods both have advantages and disadvantages. Nevertheless, by using SCNT to generate patient-specific cell lines, it eliminates complications by avoiding the use of viral vectors during iPS generation. Success in in vitro matured eggs from aged women and even differentiation of oocytes from germ stem cells will further enhance the application of SCNT in regenerative medicine.Conclusion: Human SCNT may be an appropriate mean of generating patient stem cell lines for clinical therapy in the near future.


2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Keiko Koga ◽  
Bo Wang ◽  
Shin Kaneko

Abstract In 2007, Human-induced pluripotent stem cells (iPSCs) were generated by transducing four genes (Oct3/4, Sox2, Klf4, c-Myc). Because iPSCs can differentiate into any types of cells in the body and have fewer ethical issues compared to embryonic stem (ES) cells, application of iPSCs for regenerative medicine has been actively examined. In fact, iPSCs have already been used for clinical applications, but at present, only autologous iPSC-derived grafts or HLA homozygous iPSC-derived grafts are being transplanted into patients following HLA matching. HLA is an important molecule that enables the immune system differentiates between self and non-self-components; thus, HLA mismatch is a major hurdle in the transplantation of iPSCs. To deliver inexpensive off-the-shelf iPSC-derived regenerative medicine products to more patients, it is necessary to generate universal iPSCs that can be transplanted regardless of the HLA haplotypes. The current strategy to generate universal iPSCs has two broad aims: deleting HLA expression and avoiding attacks from NK cells, which are caused by HLA deletion. Deletion of B2M and CIITA genes using the CRISPR/Cas9 system has been reported to suppress the expression of HLA class I and class II, respectively. Transduction of NK inhibitory ligands, such as HLA-E and CD47, has been used to avoid NK cell attacks. Most recently, the HLA-C retaining method has been used to generate semi-universal iPSCs. Twelve haplotypes of HLA-C retaining iPSCs can cover 95% of the global population. In future, studying which types of universal iPSCs are most effective for engraftment in various physiological conditions is necessary.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 780
Author(s):  
Issei Saitoh ◽  
Masahiro Sato ◽  
Yuki Kiyokawa ◽  
Emi Inada ◽  
Yoko Iwase ◽  
...  

Induced tissue-specific stem cells (iTSCs) are partially reprogrammed cells which have an intermediate state, such as progenitors or stem cells. They originate from the de-differentiation of differentiated somatic cells into pluripotent stem cells, such as induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs), or from the differentiation of undifferentiated cells. They show a limited capacity to differentiate and a morphology similar to that of somatic cell stem cells present in tissues, but distinct from that of iPSCs and ESCs. iTSCs can be generally obtained 7 to 10 days after reprogramming of somatic cells with Yamanaka’s factors, and their fibroblast-like morphology remains unaltered. iTSCs can also be obtained directly from iPSCs cultured under conditions allowing cellular differentiation. In this case, to effectively induce iTSCs, additional treatment is required, as exemplified by the conversion of iPSCs into naïve iPSCs. iTSCs can proliferate continuously in vitro, but when transplanted into immunocompromised mice, they fail to generate solid tumors (teratomas), implying loss of tumorigenic potential. The low tendency of iTSCs to elicit tumors is beneficial, especially considering applications for regenerative medicine in humans. Several iTSC types have been identified, including iTS-L, iTS-P, and iTS-D, obtained by reprogramming hepatocytes, pancreatic cells, and deciduous tooth-derived dental pulp cells, respectively. This review provides a brief overview of iPSCs and discusses recent advances in the establishment of iTSCs and their possible applications in regenerative medicine.


2020 ◽  
Vol 15 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Gaifang Wang ◽  
Maryam Farzaneh

Primary Ovarian Insufficiency (POI) is one of the main diseases causing female infertility that occurs in about 1% of women between 30-40 years of age. There are few effective methods for the treatment of women with POI. In the past few years, stem cell-based therapy as one of the most highly investigated new therapies has emerged as a promising strategy for the treatment of POI. Human pluripotent stem cells (hPSCs) can self-renew indefinitely and differentiate into any type of cell. Human Embryonic Stem Cells (hESCs) as a type of pluripotent stem cells are the most powerful candidate for the treatment of POI. Human-induced Pluripotent Stem Cells (hiPSCs) are derived from adult somatic cells by the treatment with exogenous defined factors to create an embryonic-like pluripotent state. Both hiPSCs and hESCs can proliferate and give rise to ectodermal, mesodermal, endodermal, and germ cell lineages. After ovarian stimulation, the number of available oocytes is limited and the yield of total oocytes with high quality is low. Therefore, a robust and reproducible in-vitro culture system that supports the differentiation of human oocytes from PSCs is necessary. Very few studies have focused on the derivation of oocyte-like cells from hiPSCs and the details of hPSCs differentiation into oocytes have not been fully investigated. Therefore, in this review, we focus on the differentiation potential of hPSCs into human oocyte-like cells.


2009 ◽  
Vol 1 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Mark Denham ◽  
Jessie Leung ◽  
Cheryl Tay ◽  
Raymond C.B. Wong ◽  
Peter Donovan ◽  
...  

2021 ◽  
Vol 22 (9) ◽  
pp. 5011
Author(s):  
Daehwan Kim ◽  
Sangho Roh

Stem cell research is essential not only for the research and treatment of human diseases, but also for the genetic preservation and improvement of animals. Since embryonic stem cells (ESCs) were established in mice, substantial efforts have been made to establish true ESCs in many species. Although various culture conditions were used to establish ESCs in cattle, the capturing of true bovine ESCs (bESCs) has not been achieved. In this review, the difficulty of establishing bESCs with various culture conditions is described, and the characteristics of proprietary induced pluripotent stem cells and extended pluripotent stem cells are introduced. We conclude with a suggestion of a strategy for establishing true bESCs.


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