A New Human Somatic Stem Cell from Placental Cord Blood with Intrinsic
Pluripotent Differentiation Potential
Koegler, Gesine; Sensken, Sandra; Airey, Judith A; Trapp, Thorsten;
Mueschen, Markus; Feldhahn, Niklas; Liedtke, Stefanie; Sorg, Ruediger V;
Fischer, Johannes; Rosenbaum, Claudia; Greschat, Susanne; Knipper, Andreas;
Bender, Joerg; Degistirici, Oezer; Gao, Jizong; Caplan, Arnold I; Colletti,
Evan J; Almeida-Porada, Graca; Mueller, Hans W; Zanjani, Esmail; Wernet,
Journal of Experimental Medicine [J. Exp. Med.]. Vol. 200, no. 2,
pp. 123-135. 19 Jul 2004.
Here a new, intrinsically pluripotent,
CD45-negative population from human cord blood, termed unrestricted somatic
stem cells (USSCs) is described. This rare population grows adherently and
can be expanded to 10 super(15) cells without losing pluripotency. In vitro
USSCs showed homogeneous differentiation into osteoblasts, chondroblasts,
adipocytes, and hematopoietic and neural cells including astrocytes and
neurons that express neurofilament, sodium channel protein, and various
neurotransmitter phenotypes. Stereotactic implantation of USSCs into intact
adult rat brain revealed that human Tau-positive cells persisted for up to
3 mo and showed migratory activity and a typical neuron-like morphology. In
vivo differentiation of USSCs along mesodermal and endodermal pathways was
demonstrated in animal models. Bony reconstitution was observed after
transplantation of USSC-loaded calcium phosphate cylinders in nude rat
femurs. Chondrogenesis occurred after transplanting cell-loaded gelfoam
sponges into nude mice. Transplantation of USSCs in a noninjury model, the
preimmune fetal sheep, resulted in up to 5% human hematopoietic
engraftment. More than 20% albumin-producing human parenchymal hepatic
cells with absence of cell fusion and substantial numbers of human
cardiomyocytes in both atria and ventricles of the sheep heart were
detected many months after USSC transplantation. No tumor formation was
observed in any of these animals.
Adult stem cells - reprogramming neurological repair?
Rice, CM; Scolding, NJ*
Lancet [Lancet]. Vol. 364, no. 9429, pp. 193-199.
0-16 Jul 2004.
Much excitement has surrounded recent breakthroughs in
embryonic stem-cell research. Of lower profile, but no less exciting, are
the advances in the field of adult stem-cell research, and their
implications for cell therapy. Clinical experience from use of adult
haemopoietic stem cells in haematology will facilitate and hasten
transition from laboratory to clinic - indeed, clinical trials using adult
human stem cells are already in progress in some disease states, including
myocardial ischaemia. Here, with particular reference to neurology, we
review processes that might underlie apparent changes in adult cell
phenotype. We discuss implications these processes might have for the
development of new therapeutic strategies using adult stem cells.
Rat adult stem cells (marrow stromal cells) engraft and differentiate in
chick embryos without evidence of cell fusion
Pochampally, RR; Neville, BT; Schwarz, EJ; Li, MM; Prockop,
Proceedings of the National Academy of Sciences, USA [Proc. Natl.
Acad. Sci. USA]. Vol. 101, no. 25, pp. 9282-9285. 22 Jun 2004.
fusion was recently reported to account for the plasticity of adult stem
cells in vivo. Adult stem cells, referred to as mesenchymal stem cells or
marrow stromal cells, from rat marrow, were infused into 1.5- to 2-day-old
chick embryos. After 4 days, the rat cells had expanded 1.3- to 33-fold in
one- third of surviving embryos. The cells engrafted into many tissues, and
no multinuclear cells were detected. The most common site of engraftment
was the heart, apparently because the cells were infused just above the
dorsal aorta. Some of the cells in the heart expressed cardiotin, and alpha
-heavy-chain myosin. GFP super(+) cells reisolated from the embryos had a
rat karyotype. Therefore, the cells engrafted and partially differentiated
without evidence of cell fusion.
Adult pancreatic beta -cells are formed by self-duplication rather than
Dor, Yuval; Brown, Juliana; Martinez, Olga I; Melton, Douglas A
[Nature]. Vol. 429, no. 6987, pp. 41-46. 6 May 2004.
How tissues generate
and maintain the correct number of cells is a fundamental problem in
biology. In principle, tissue turnover can occur by the differentiation of
stem cells, as is well documented for blood, skin and intestine, or by the
duplication of existing differentiated cells. Recent work on adult stem
cells has highlighted their potential contribution to organ maintenance and
repair. However, the extent to which stem cells actually participate in
these processes in vivo is not clear. Here we introduce a method for
genetic lineage tracing to determine the contribution of stem cells to a
tissue of interest. We focus on pancreatic beta -cells, whose postnatal
origins remain controversial. Our analysis shows that pre-existing beta
-cells, rather than pluripotent stem cells, are the major source of new
beta -cells during adult life and after pancreatectomy in mice. These
results suggest that terminally differentiated beta -cells retain a
significant proliferative capacity in vivo and cast doubt on the idea that
adult stem cells have a significant role in beta -cell replenishment.
Plasticity of Adult Stem Cells
Wagers, AJ; Weissman, IL
Cell [Cell]. Vol. 116, no. 5, pp. 639-648. Mar
Recent years have seen much excitement over the possibility that
adult mammalian stem cells may be capable of differentiating across tissue
lineage boundaries, and as such may represent novel, accessible, and very
versatile effectors of therapeutic tissue regeneration. Yet studies
proposing such 'plasticity' of adult somatic stem cells remain
controversial, and in general, existing evidence suggests that in vivo such
unexpected transformations are exceedingly rare and in some cases can be
accounted for by equally unexpected alternative explanations.
Adult Cardiac Sca-1-positive Cells Differentiate into Beating
Matsuura, K; Nagai, T; Nishigaki, N; Oyama, T; Nishi, J; Wada, H; Sano, M;
Toko, H; Akazawa, H; Sato, T; Nakaya, H; Kasanuki, H; Komuro, I
of Biological Chemistry [J. Biol. Chem.]. Vol. 279, no. 12, pp.
11384-11391. 19 Mar 2004.
Although somatic stem cells have been reported
to exist in various adult organs, there have been few reports concerning
stem cells in the heart. We here demonstrate that Sca-1-positive (Sca-1+)
cells in adult hearts have some of the features of stem cells. Sca-1+ cells
were isolated from adult murine hearts by a magnetic cell sorting system
and cultured on gelatin-coated dishes. A fraction of Sca-1+ cells stuck to
the culture dish and proliferated slowly. When treated with oxytocin,
Sca-1+ cells expressed genes of cardiac transcription factors and
contractile proteins and showed sarcomeric structure and spontaneous
beating. Isoproterenol treatment increased the beating rate, which was
accompanied by the intracellular Ca super(2+) transients. The cardiac
Sca-1+ cells expressed oxytocin receptor mRNA, and the expression was
up-regulated after oxytocin treatment. Some of the Sca-1+ cells expressed
alkaline phosphatase after osteogenic induction and were stained with
Oil-Red O after adipogenic induction. These results suggest that Sca-1+
cells in the adult murine heart have potential as stem cells and may
contribute to the regeneration of injured hearts.
Adipogenic Differentiation of Human Adult Stem Cells From Bone Marrow
Sekiya, I; Larson, BL; Vuoristo, JT; Cui, J-G; Prockop, DJ
Bone and Mineral Research [J. Bone Miner. Res.]. Vol. 19, no. 2, pp.
256-264. Feb 2004.
We assayed gene expressions during adipogenesis of
human MSCs. Microarray assays demonstrated time-dependent increases in
expression of 67 genes, including 2 genes for transcription factors that
were not previously shown to be expressed during adipogenesis.
Introduction: Increased numbers of bone marrow adipocytes have been
observed in patients with osteoporosis and aplastic anemia, but the
pathological mechanisms remain unknown. Recently, microarray assays for
mRNAs were used to follow adipogenic differentiation of the preadipocytic
cell line, 3T3-L1, but adipogenic differentiation has not been examined in
primary cells from bone marrow. Here we defined the sequence of gene
expression during the adipogenesis ex vivo of human cells from bone marrow
referred to as either mesenchymal stem cells or marrow stromal cells
(MSCs). Materials and Methods: MSCs were plated at extremely low densities
to generate single-cell derived colonies, and adipogenic differentiation of
the colonies assayed by accumulation of fat vacuoles, time-lapse
photomicroscopy, microarrays, and reverse transcriptase-polymerase chain
reaction (RT-PCR) assays. Results and Conclusions: About 30% of the
colonies differentiated to adipocytes in 14 days and about 60% in 21 days.
Cell proliferation was inhibited by approximately 50% in adipogenic medium.
The differentiation occurred primarily at the center of the colonies, and a
few adipocytes that formed near the periphery migrated toward the centers.
RT-PCR assays demonstrated that the differentiation was accompanied by
increases in a series of genes previously shown to increase with adipogenic
differentiation: peroxisome proliferator activated receptor gamma , CCAAT
enhancer-binding protein alpha , acylCoA synthetase, lipoprotein lipase,
and fatty acid binding protein 4. We also followed differentiation with
microarray assays. Sixty-seven genes increased more than 10-fold at day 1
and 20-fold at day 7, 14, or 21. Many of the genes identified were
previously shown to be expressed during adipocytic differentiation.
However, others, such as zinc finger E-box binding protein and zinc finger
protein 145, were not. This study should serve as a basis for future study
to clarify the mechanisms of adipocyte differentiation of MSCs.
Stem cells in the skin: waste not, Wnt not
Alonso, L; Fuchs, E
Genes & Development [Genes Dev.]. Vol. 17, no. 10,
pp. 1189-1200. 15 May 2003.
Although it seems unlikely that adult stem
cells harvested from one tissue might be reprogrammed to take on the
characteristics of a different cell type, several tantalizing results have
encouraged researchers to consider this possibility. Before scientists can
begin to define the limits of adult stem cell plasticity, they need to
understand the signals that instruct multipotent cells to self-renew and
differentiate within the lineages of their resident tissues. Skin is an
excellent model system in which to explore these fundamental mechanisms,
because skin keratinocytes are easily accessible and are one of the few
adult stem cell types that can be maintained and propagated in vitro. These
cells have already been engrafted long term to replace damaged epidermis on
burn patients. Now skin biologists have begun to identify some of the key
steps involved in generating a functional tissue from multipotent stem
Clonal expansion of adult rat hepatic stem cell lines by suppression of
asymmetric cell kinetics (SACK)
Lee, H-S; Crane, GG; Merok, JR; Tunstead, JR; Hatch, NL; Panchalingam, K;
Powers, MJ; Griffith, LG; Sherley, JL*
Biotechnology and Bioengineering
[Biotechnol. Bioeng.]. Vol. 83, no. 7, pp. 760-771. 2003.
cells have potential use for several biomedical applications, including
cell replacement therapy, gene therapy, and tissue engineering. However,
such applications have been limited due to difficulties encountered in
expanding functional adult stem cells. We have developed a new approach to
the problem of adult stem cell expansion based on the suppression of
asymmetric cell kinetics (SACK). We postulated that asymmetric cell
kinetics, required for adult stem cell function, were a major barrier to
their expansion in culture. As such, conversion of adult stem cells from
asymmetric cell kinetics to symmetric cell kinetics would promote their
exponential expansion and longterm propagation in culture. The purine
nucleoside xanthosine (Xs), which promotes guanine ribonucleotide
biosynthesis, can be used to reversibly convert cells from asymmetric cell
kinetics to symmetric cell kinetics. We used Xs supplementation to derive
clonal epithelial cell lines from adult rat liver that have properties of
adult hepatic stem cells. The properties of two Xs-derived cell lines,
Lig-8 and Lig-13, are described in detail and compared to properties of
adult rat hepatic cell lines derived without Xs supplementation. The
Xs-derived cell lines exhibit Xs-dependent asymmetric cell kinetics and
Xs-dependent expression of mature hepatic differentiation markers.
Interestingly, Lig-8 cells produce progeny with properties consistent with
hepatocyte differentiation, while Lig-13 progeny cells have properties
consistent with bile duct epithelium differentiation. A stable adult
cholangiocyte stem cell line has not been previously described. Consistent
with the principles of their derivation, the SACK-derived hepatic cell
lines exhibit neither senescence nor tumorigenic properties, and their
differentiation properties are stable after longterm culture. These
characteristics of SACK-derived stem cell lines underscore asymmetric cell
kinetics as an essential adult stem cell property with potential to be the
basis for a general approach to expansion and propagation of diverse adult
"Stemness": Transcriptional Profiling of Embryonic and Adult Stem
Ramalho-Santos, M; Yoon, S; Matsuzaki, Y; Mulligan, RC; Melton,
Science (Washington) [Science (Wash.)]. Vol. 298, no. 5593, pp.
597-600. 18 Oct 2002.
The transcriptional profiles of mouse embryonic,
neural, and hematopoietic stem cells were compared to define a genetic
program for stem cells. A total of 216 genes are enriched in all three
types of stem cells, and several of these genes are clustered in the
genome. When compared to differentiated cell types, stem cells express a
significantly higher number of genes (represented by expressed sequence
tags) whose functions are unknown. Embryonic and neural stem cells have
many similarities at the transcriptional level. These results provide a
foundation for a more detailed understanding of stem cell biology.
Plasticity of hematopoietic stem cells and cellular memory
Avots, A; Harder, F; Schmittwolf, C; Petrovic, S; Mueller,
Immunological Reviews [Immunol. Rev.]. Vol. 187, pp. 9-21. Sep
Stem cell systems represent an effective and powerful approach for
tissue development and regeneration of diverse tissue types. Common and
defining features of these exceptional cells are the capacity for
self-renewal and the potential for differentiation into multiple mature
cell types. Recently, surprising new observations have indicated that stem
cells isolated from one adult tissue can also give rise to mature cells of
other cell lineages, irrespective of classical germ layer designations.
This discovery has resulted in quantum leaps in both scientific knowledge
and the potential applications of stem cells. The new findings contradict
central dogmas of commitment and differentiation of stem and progenitor
cells. However, the true potential of somatic stem cells is just emerging
and the new findings have to be defined more fully and integrated into a
unifying model of stem cell potential and behavior. Here we analyze the
developmental potential of hematopoietic stem cells of mouse and man
following their injection into the murine preimplantation blastocyst, an
environment that allows the development of all cell lineages. In addition,
we discuss the emerging lines of evidence of the developmental plasticity
of hematopoietic and other somatic stem cells and consider how cellular
memory of transcriptional states is established and may be potentially
involved in this phenomenon.