Comprehensive Report: Role of Stem Cells in Tissue & Organ Development

This report delves into the multifaceted role of stem cells in tissue and organ development. It begins by differentiating between primordial germ cells and stem cells, highlighting their distinct functions. The report then explores stem cell markers, which are crucial for identifying and isolating stem cells, and discusses the applications of gene knockout techniques. Furthermore, it examines the use of embryonic stem cell lines, directed differentiation, and direct reprogramming methods in the context of regenerative medicine and drug discovery. The report also covers various types of stem cells, including those derived from amniotic fluid, cord blood, hematopoietic stem cells, mesenchymal stem cells, and pluripotent stem cells. It provides detailed information on each type, including their characteristics, applications, and advantages, supported by relevant references.

Running head: ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 1
Role of Stem Cell in Tissue and Organ Development
Name of the Student
Name of the University
Author Note

ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 2
Difference between primordial germ cell and stem cell
Primordial germ cell (PGC) is the precursor of embryonic stem cells. The primordial
germ cell which is present within the embryo develops into stem cells which leads to the
production of reproductive gametes (sperm or eggs) in adults. The PGC are subsets of stem
cells used for creating a new combination of alleles which divides by meiosis to give rise to
haploid gametes that combine to form genetically different offspring. Stem cells, on the other
hand, possess self-renewal property and give rise to the production of progeny cells which
again differentiates to form different cell types(Stanfordchildrens.org, 2020).
The antigenic determinants present on the stem cells are also known as stem cell
markers, they help in the identification of stem cells. The embryonic stem cell is identified by
the presence of TRA-1-60 and TRA-1-81 antigens on the surface of human embryonal
carcinoma cells(EC) cells and human pluripotent stem cells. Some other transcriptional
factors such as Oct4, Nanog, Sall4, Essrb, Tbx3 have been found to affect the pluripotency of
the stem cells. Haematopoetic stem cells or progenitor cells are identified by CD117(c-kit),
CD150 markers, also Sca-1, Lin- and IL7R+ have been used to study the lineage of
hematopoietic stem cells or lymphopoiesis(Hirata et al, 2019). Mesenchymal stem cell
markers include CD10, CD13, CD271 etcetera. The stem cell markers are advantageous for
the fact that they allow for recovery of live cells with multiparameter labeling, as a result, the
recovered cells can be readily applied to functional stem cell analyses, moreover, the stem
cell markers have allowed purification of stem cells and their ability to be cultured again. One
limitation of stem cell marker being the risk of formation of teratoma or immune rejection
after transplantation, and there is a lack of proper knowledge about the benefits of using such
markers.

ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 3
Gene knockout by targeted mutation
[Source: Genecopoeia, 2020]
Application of gene knockout
 Genome engineering.
 To study the function of a particular gene.
 Helps in monitoring and controlling the effect of a gene.
 It also helps in the construction of a genetically modified organism
Use of embryonic stem cell line
 Replenish damaged and injured cell or tissue
 Drug discovery and toxicological studies

ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 4
 For identifying drug target
 Used to study cell differentiation
Directed differentiation
 Directed differentiation is a bioengineering method used particularly in stem cell
biology, tissue engineering and developmental biology. This method exposes the cells
to specific signalling pathway modulators and manipulates the cell culture in such a
way that it mimics the natural environment for the development of a given cell type.
This method is used mainly in drug discovery and toxicological studies, disease
modelling and production of regenerative medicines(Kaminski et al, 2017).
 One disadvantage of this method is one has to have sufficient prior knowledge and
understanding about the process of development of a particular cell type.
Direct reprogramming
 Directed reprogramming is also known as transdifferentiation or direct conversion. It
consists of several transcription factors which are introduced within a cell and are
overexpressed. The starting material is usually either a pluripotent stem cell or
differentiated cell types like fibroblast(Prasad et al, 2016).
 One drawback of this method is the introduction of foreign nucleic acid within a cell,
followed by the induced expression of the transcription factors, whose effects are not
yet fully understood.

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[So
urce: Molecular Biotechnology and Stem Cell Research, 2020]
Types of Stem cell
Stem cell derived from amniotic fluid and cord blood
Stem cells are also found in the amniotic fluid as well as in the amniotic membrane.
The amniotic stem cells are mainly composed of adherent cells such as epithelial cells and
fibroblastic cells(Stemcells.nih.gov, 2020).
Umbilical cord blood is also called placental blood which acts as an abundant source of
young stem cells having the ability to multiply rapidly. The umbilical cord also contains
haematopoetic progenitor stem cells and precursor of other cells.
Haematopoietic stem cell
Haematopoetic stem cells are pluripotent progenitor stem cells that develop from the
mesodermal hemangioblast cells, giving rise to other blood cells through haematopoiesis.

ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 6
They have self-renewal property giving rise to specialised cells which comes out of the bone
marrow into the blood circulation. HSC are mostly present in bone marrow, umbilical cord
blood and peripheral blood.
Peripheral blood stem cell
Peripheral blood stem cell is a potential source of hematopoietic stem cells. They are
the cellular component of blood consisting of erythrocytes, leukocytes and platelets.
Mesenchymal stem cell
The Mesenchymal stem cell is pluripotent stromal cells which divide into various
kinds of cells such as osteoblast, chondrocytes, myocytes and adipocytes. They function in
the regulation of homeostasis and also help in the proliferation and differentiation of
Haematopoetic Stem Cells.
Pluripotent stem cell
Pluripotent stem cell or master cells, are self-replicating cells developed from the
embryo or fetal tissue. They expand to form the three primary germ cells such as ectoderm,
mesoderm and endoderm.

ROLE OF STEM CELL IN TISSUE AND ORGAN DEVELOPMENT 7
REFERENCE
Hirata, Y., Kakiuchi, M., Robson, S. C., & Fujisaki, J. (2019). CD150high CD4 T cells and
CD150high regulatory T cells regulate hematopoietic stem cell quiescence via
CD73. haematologica, 104(6), 1136-1142.
Kaminski, M. M., Tosic, J., Pichler, R., Arnold, S. J., & Lienkamp, S. S. (2017). Engineering
kidney cells: reprogramming and directed differentiation to renal tissues. Cell and
tissue research, 369(1), 185-197.
Knockout by TALEN or CRISPR vs. by shRNA/siRNA | Genecopoeia. Genecopoeia.com.
(2020). Retrieved 22 February 2020, from
https://www.genecopoeia.com/resource/knockout-by-talen-or-crispr/.
Leibniz Forschungslaboratorien für Biotechnologie und künstliche Organe - Molecular
Biotechnology and Stem Cell Research. Lebao.eu. (2020). Retrieved 22 February
2020, from https://www.lebao.eu/areas-of-research/molecular-biotechnology-and-
stem-cell-research/.
Prasad, A., Manivannan, J., Loong, D. T., Chua, S. M., Gharibani, P. M., & All, A. H.
(2016). A review of induced pluripotent stem cell, direct conversion by trans-
differentiation, direct reprogramming and oligodendrocyte
differentiation. Regenerative medicine, 11(2), 181-191.
Stanford Children's Health. Stanfordchildrens.org. (2020). Retrieved 22 February 2020, from
https://www.stanfordchildrens.org/en/topic/default?id=what-are-stem-cells-160-38.
Stem Cell Basics I. | stemcells.nih.gov. Stemcells.nih.gov. (2020). Retrieved 22 February
2020, from https://stemcells.nih.gov/info/basics/1.htm.

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