A Mystery Unraveled: Non-tumorigenic pluripotent stem cells in human adult tissues

Embryonic stem cells and induced pluripotent stem cells have emerged as the gold standard of pluripotent stem cells and the class of 10 stem cell with the highest potential for contribution to regenerative and therapeutic application; however, their translational use is often impeded by teratoma formation, commonly associated with pluripotency. We discuss a population of nontumorigenic pluripotent stem cells, termed Multilineage Differentiating Stress Enduring (Muse) cells, which offer an innovative and 15 exciting avenue of exploration for the potential treatment of various human diseases. Areas covered: This review discusses the origin of Muse cells, describes in detail their various unique characteristics, and considers future avenues of their application and investigation with respect to what is currently known 20 of adult pluripotent stem cells in scientific literature. We begin by defining cell potency, then discussing both mesenchymal and various reported populations of pluripotent stem cells, and finally, delving into Muse cells and what sets them apart from their contemporaries. Expert opinion: Muse cells derived from adipose tissue (Muse-AT) are 25 efficiently, routinely and painlessly isolated from human lipoaspirate material, exhibit tripoblastic differentiation both spontaneously and under media-specific induction, and do not form teratomas. We describe qualities specific to Muse-ATcells and their potential impact on the field of regenerative medicine and cell therapy.Fil: Simerman, Ariel A.. University of California; Estados UnidosFil: Perone, Marcelo Javier. University of California; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires; ArgentinaFil: Gimeno, Maria Laura. University of California; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires; ArgentinaFil: Dumesic, Daniel A.. University of California; Estados UnidosFil: Chazenblak, Gregorio D.. University of California; Estados Unido

Muse Cells: Nontumorigenic Pluripotent Stem Cells Present in Adult Tissues—A Paradigm Shift in Tissue Regeneration and Evolution

Muse cells are a novel population of nontumorigenic pluripotent stem cells, highly resistant to cellular stress. These cells are present in every connective tissue and intrinsically express pluripotent stem markers such as Nanog, Oct3/4, Sox2, and TRA1-60. Muse cells are able to differentiate into cells from all three embryonic germ layers both spontaneously and under media-specific induction. Unlike ESCs and iPSCs, Muse cells exhibit low telomerase activity and asymmetric division and do not undergo tumorigenesis or teratoma formation when transplanted into a host organism. Muse cells have a high capacity for homing into damaged tissue and spontaneous differentiation into cells of compatible tissue, leading to tissue repair and functional restoration. The ability of Muse cells to restore tissue function may demonstrate the role of Muse cells in a highly conserved cellular mechanism related to cell survival and regeneration, in response to cellular stress and acute injury. From an evolutionary standpoint, genes pertaining to the regenerative capacity of an organism have been lost in higher mammals from more primitive species. Therefore, Muse cells may offer insight into the molecular and evolutionary bases of autonomous tissue regeneration and elucidate the molecular and cellular mechanisms that prevent mammals from regenerating limbs and organs, as planarians, newts, zebrafish, and salamanders do

Awakened by cellular stress: isolation and characterization of a novel population of pluripotent stem cells derived from human adipose tissue.

Advances in stem cell therapy face major clinical limitations, particularly challenged by low rates of post-transplant cell survival. Hostile host factors of the engraftment microenvironment such as hypoxia, nutrition deprivation, pro-inflammatory cytokines, and reactive oxygen species can each contribute to unwanted differentiation or apoptosis. In this report, we describe the isolation and characterization of a new population of adipose tissue (AT) derived pluripotent stem cells, termed Multilineage Differentiating Stress-Enduring (Muse) Cells, which are isolated using severe cellular stress conditions, including long-term exposure to the proteolytic enzyme collagenase, serum deprivation, low temperatures and hypoxia. Under these conditions, a highly purified population of Muse-AT cells is isolated without the utilization of cell sorting methods. Muse-AT cells grow in suspension as cell spheres reminiscent of embryonic stem cell clusters. Muse-AT cells are positive for the pluripotency markers SSEA3, TR-1-60, Oct3/4, Nanog and Sox2, and can spontaneously differentiate into mesenchymal, endodermal and ectodermal cell lineages with an efficiency of 23%, 20% and 22%, respectively. When using specific differentiation media, differentiation efficiency is greatly enhanced in Muse-AT cells (82% for mesenchymal, 75% for endodermal and 78% for ectodermal). When compared to adipose stem cells (ASCs), microarray data indicate a substantial up-regulation of Sox2, Oct3/4, and Rex1. Muse-ATs also exhibit gene expression patterns associated with the down-regulation of genes involved in cell death and survival, embryonic development, DNA replication and repair, cell cycle and potential factors related to oncogenecity. Gene expression analysis indicates that Muse-ATs and ASCs are mesenchymal in origin; however, Muse-ATs also express numerous lymphocytic and hematopoietic genes, such as CCR1 and CXCL2, encoding chemokine receptors and ligands involved in stem cell homing. Being highly resistant to severe cellular stress, Muse-AT cells have the potential to make a critical impact on the field of regenerative medicine and cell-based therapy

Pluripotent nontumorigenic multilineage differentiating stress enduring cells (Muse cells): a seven-year retrospective.

Multilineage differentiating stress enduring (Muse) cells, discovered in the spring of 2010 at Tohoku University in Sendai, Japan, were quickly recognized by scientists as a possible source of pluripotent cells naturally present within mesenchymal tissues. Muse cells normally exist in a quiescent state, singularly activated by severe cellular stress in vitro and in vivo. Muse cells have the capacity for self-renewal while maintaining pluripotent cell characteristics indicated by the expression of pluripotent stem cell markers. Muse cells differentiate into cells representative of all three germ cell layers both spontaneously and under media-specific induction. In contrast to embryonic stem and induced pluripotent stem cells, Muse cells exhibit low telomerase activity, a normal karyotype, and do not undergo tumorigenesis once implanted in SCID mice. Muse cells efficiently home into damaged tissues and differentiate into specific cells leading to tissue regeneration and functional recovery as described in different animal disease models (i.e., fulminant hepatitis, muscle degeneration, skin ulcers, liver cirrhosis, cerebral stroke, vitiligo, and focal segmental glomerulosclerosis). Circulating Muse cells have been detected in peripheral blood, with higher levels present in stroke patients during the acute phase. Furthermore, Muse cells have inherent immunomodulatory properties, which could contribute to tissue generation and functional repair in vivo. Genetic studies in Muse cells indicate a highly conserved cellular mechanism as seen in more primitive organisms (yeast, Saccharomyces cerevisiae, Caenorhabditis elegans, chlamydomonas, Torpedo californica, drosophila, etc.) in response to cellular stress and acute injury. This review details the molecular and cellular properties of Muse cells as well as their capacity for tissue repair and functional recovery, highlighting their potential for clinical application in regenerative medicine

Pluripotent nontumorigenic multilineage differentiating stress enduring cells (Muse cells): a seven-year retrospective

Abstract Multilineage differentiating stress enduring (Muse) cells, discovered in the spring of 2010 at Tohoku University in Sendai, Japan, were quickly recognized by scientists as a possible source of pluripotent cells naturally present within mesenchymal tissues. Muse cells normally exist in a quiescent state, singularly activated by severe cellular stress in vitro and in vivo. Muse cells have the capacity for self-renewal while maintaining pluripotent cell characteristics indicated by the expression of pluripotent stem cell markers. Muse cells differentiate into cells representative of all three germ cell layers both spontaneously and under media-specific induction. In contrast to embryonic stem and induced pluripotent stem cells, Muse cells exhibit low telomerase activity, a normal karyotype, and do not undergo tumorigenesis once implanted in SCID mice. Muse cells efficiently home into damaged tissues and differentiate into specific cells leading to tissue regeneration and functional recovery as described in different animal disease models (i.e., fulminant hepatitis, muscle degeneration, skin ulcers, liver cirrhosis, cerebral stroke, vitiligo, and focal segmental glomerulosclerosis). Circulating Muse cells have been detected in peripheral blood, with higher levels present in stroke patients during the acute phase. Furthermore, Muse cells have inherent immunomodulatory properties, which could contribute to tissue generation and functional repair in vivo. Genetic studies in Muse cells indicate a highly conserved cellular mechanism as seen in more primitive organisms (yeast, Saccharomyces cerevisiae, Caenorhabditis elegans, chlamydomonas, Torpedo californica, drosophila, etc.) in response to cellular stress and acute injury. This review details the molecular and cellular properties of Muse cells as well as their capacity for tissue repair and functional recovery, highlighting their potential for clinical application in regenerative medicine

Identification of functional groups and canonical pathways in Muse-ATs vs ASCs.

<p>Identification of the top ten (<b>A</b>) functional groups (<b>B</b>) canonical pathways of all differentially expressed genes (2 fold or higher) in Muse-AT cells versus ASCs. Fischer’s exact test was used to calculate a p-value determining the probability of the association between the genes in the data set with functional groups and canonical pathways. Both (<b>A</b>) functional groups (<b>B</b>) canonical pathways are displayed along the x-axis, while the y-axis displays logarithm of p values calculated by Fisher exact between the ratio of the number of genes differentially expressed genes (2 fold or higher) in Muse-AT versus ASCs in a given functional group or pathway divided by total number of genes that make up that functional group or pathway with a threshold for statistical significance set at 0.05. The analysis was performed by Ingenuity Pathways analysis software.</p

Muse-ATs express pluripotent stem cell markers.

<p>Immunofluorescence microscopy demonstrates that Muse-AT aggregates, along with individual Muse-AT cells, express characteristic pluripotent stem cell markers, including SSEA3, Oct3/4, Nanog, Sox2, and TRA1-60. Comparatively, ASCs (right panel) derived from the same lipoaspirate under standard conditions (see above, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064752#pone.0064752-Zuk1" target="_blank">[16]</a> were negative for these pluripotent stem cell markers. Nuclei were stained with DAPI (blue). Original magnification, 600 X.</p

Intrafollicular cortisol levels inversely correlate with cumulus cell lipid content as a possible energy source during oocyte meiotic resumption in&nbsp;women undergoing ovarian stimulation for in&nbsp;vitro fertilization

ObjectiveTo determine whether follicular fluid (FF) cortisol levels affect cumulus cell (CC) lipid content during oocyte meiotic resumption, and whether CCs express genes for glucocorticoid action.DesignProspective cohort study.SettingAcademic medical center.Patient(s)Thirty-seven nonobese women underwent ovarian stimulation for in vitro fertilization (IVF).Intervention(s)At oocyte retrieval, FF was aspirated from the first follicle (&gt;16 mm in size) of each ovary and pooled CCs were collected.Main outcome measure(s)Follicular fluid cortisol and cortisone analysis was performed with the use of liquid chromatography-tandem mass spectrometry. CCs were stained with lipid fluorescent dye Bodipy FL C16 to determine lipid content with the use of confocal microscopy. Quantitative real-time polymerase chain reaction was used to detect CC gene expression of 11β-hydroxysteroid dehydrogenase (11β-HSD) types 1 and 2, glucocorticoid receptor (NR3C1), lipoprotein lipase (LPL), and hormone-sensitive lipase (HSL).Result(s)Adjusting for maternal age, FF cortisol levels negatively correlated with CC lipid content and positively correlated with numbers of total and mature oocytes. CCs expressed genes for 11β-HSD type 1 as the predominant 11β-HSD isoform, NR3C1, LPL, and HSL.Conclusion(s)FF cortisol levels may regulate CC lipolysis during oocyte meiotic resumption and affect oocyte quality during IVF

Muse-ATs can differentiate to endodermal cell lineages.

<p>Isolated Muse-ATs were grown as adherent cells in the presence of DMEM/10%FCS for 6 days. (<b>A</b>) Immunostaining indicates that Muse-AT have the capacity to spontaneously differentiate to endodermal cell lineages. α-fetoprotein and pan-keratin are specific markers for hepatocytes; Nuclei were stained with DAPI (blue). Original magnification, 600 X. Comparatively, ASCs (right panel) derived from the same lipoaspirate under standard conditions (see above, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064752#pone.0064752-Zuk1" target="_blank">[16]</a>) were negative for α-fetoprotein and pan-keratin. Nuclei were stained with DAPI (blue); original magnification, 600 X; (<b>B</b>) Isolated Muse-AT cells were grown as adherent cells in the presence of hepatocyte differentiation medium <b>(see methods)</b> for 3 or 6 days and formation of hepatocytes was detected using anti-human cytokeratin 7 or α-fetoprotein antibodies. Comparatively, ASCs (right panel) were completely negative for cytokeratin 7 and α-fetoprotein <b>(B, right panel)</b>. Nuclei were stained with DAPI (blue). Original magnification was 200 X (first three rows) or 600 X (last two rows).</p