Parthenogenesis-derived Multipotent Stem Cells Adapted for Tissue Engineering Applications

PubMed Central

Koh, Chester J.; Delo, Dawn M.; Lee, Jang Won; Siddiqui, M. Minhaj; Lanza, Robert P.; Soker, Shay; Yoo, James J.; Atala, Anthony

2009-01-01

Embryonic stem cells are envisioned as a viable source of pluripotent cells for use in regenerative medicine applications when donor tissue is not available. However, most current harvest techniques for embryonic stem cells require the destruction of embryos, which has led to significant political and ethical limitations on their usage. Parthenogenesis, the process by which an egg can develop into an embryo in the absence of sperm, may be a potential source of embryonic stem cells that may avoid some of the political and ethical concerns surrounding embryonic stem cells. Here we provide the technical aspects of embryonic stem cell isolation and expansion from the parthenogenetic activation of oocytes. These cells were characterized for their stem-cell properties. In addition, these cells were induced to differentiate to the myogenic, osteogenic, adipogenic, and endothelial lineages, and were able to form muscle-like and bony-like tissue in vivo. Furthermore, parthenogenetic stem cells were able to integrate into injured muscle tissue. Together, these results demonstrate that parthenogenetic stem cells can be successfully isolated and utilized for various tissue engineering applications. PMID:18799133

Concise Review: Fabrication, Customization, and Application of Cell Mimicking Microparticles in Stem Cell Science

PubMed Central

Labriola, Nicholas R.; Azagury, Aharon; Gutierrez, Robert; Mathiowitz, Edith

2018-01-01

Abstract Stem and non‐stem cell behavior is heavily influenced by the surrounding microenvironment, which includes other cells, matrix, and potentially biomaterials. Researchers have been successful in developing scaffolds and encapsulation techniques to provide stem cells with mechanical, topographical, and chemical cues to selectively direct them toward a desired differentiation pathway. However, most of these systems fail to present truly physiological replications of the in vivo microenvironments that stem cells are typically exposed to in tissues. Thus, cell mimicking microparticles (CMMPs) have been developed to more accurately recapitulate the properties of surrounding cells while still offering ways to tailor what stimuli are presented. This nascent field holds the promise of reducing, or even eliminating, the need for live cells in select, regenerative medicine therapies, and diagnostic applications. Recent, CMMP‐based studies show great promise for the technology, yet only reproduce a small subset of cellular characteristics from among those possible: size, morphology, topography, mechanical properties, surface molecules, and tailored chemical release to name the most prominent. This Review summarizes the strengths, weaknesses, and ideal applications of micro/nanoparticle fabrication and customization methods relevant to cell mimicking and provides an outlook on the future of this technology. Moving forward, researchers should seek to combine multiple techniques to yield CMMPs that replicate as many cellular characteristics as possible, with an emphasis on those that most strongly influence the desired therapeutic effects. The level of flexibility in customizing CMMP properties allows them to substitute for cells in a variety of regenerative medicine, drug delivery, and diagnostic systems. Stem Cells Translational Medicine 2018;7:232–240 PMID:29316362

Wnt some lose some: transcriptional governance of stem cells by Wnt/β-catenin signaling

PubMed Central

Lien, Wen-Hui; Fuchs, Elaine

2014-01-01

In mammals, Wnt/β-catenin signaling features prominently in stem cells and cancers, but how and for what purposes have been matters of much debate. In this review, we summarize our current knowledge of Wnt/β-catenin signaling and its downstream transcriptional regulators in normal and malignant stem cells. We centered this review largely on three types of stem cells—embryonic stem cells, hair follicle stem cells, and intestinal epithelial stem cells—in which the roles of Wnt/β-catenin have been extensively studied. Using these models, we unravel how many controversial issues surrounding Wnt signaling have been resolved by dissecting the diversity of its downstream circuitry and effectors, often leading to opposite outcomes of Wnt/β-catenin-mediated regulation and differences rooted in stage- and context-dependent effects. PMID:25030692

Which bank? A guardian model for regulation of embryonic stem cell research in Australia.

PubMed

McLennan, A

2007-08-01

In late 2005 the Legislation Review: Prohibition of Human Cloning Act 2002 (Cth) and the Research Involving Human Embryos Act 2002 (Cth) recommended the establishment of an Australian stem cell bank. This article aims to address a lack of discussion of issues surrounding stem cell banking by suggesting possible answers to the questions of whether Australia should establish a stem cell bank and what its underlying philosophy and functions should be. Answers are developed through an analysis of regulatory, scientific and intellectual property issues relating to embryonic stem cell research in the United Kingdom, United States and Australia. This includes a detailed analysis of the United Kingdom Stem Cell Bank. It is argued that a "guardian" model stem cell bank should be established in Australia. This bank would aim to promote the maximum public benefit from human embryonic stem cell research by providing careful regulatory oversight and addressing ethical issues, while also facilitating research by addressing practical scientific concerns and intellectual property issues.

Stem cell research and transplantation: science leading ethics.

PubMed

Daar, A S; Bhatt, A; Court, E; Singer, P A

2004-10-01

One of the most exciting developments in the biological sciences in the past decade has been the discovery and characterization of human embryonic stem cells (ESCs). The interest to transplanters is the potential applications of stem cells in regenerative medicine (RM), which may involve tissue engineering, genetic engineering, and other techniques to repair, replace, or regenerate failing tissues and organs. There is little controversy surrounding human adult stem cells. However, human ESCs are surrounded by a number of ethical controversies, the extent of which is partly dependent on their source. Those derived from currently existing embryonic stem cell lines are less controversial than those derived from "excess" embryos from in vitro fertilization (IVF) clinics, while ESCs derived from IVF embryos specifically created for the purpose are not acceptable to many people arguing from religious and other moral perspectives. Somatic cell nuclear transfer, or therapeutic cloning, must be distinguished from reproductive cloning. It holds the most promise for regenerative medicine. ESCs can also be derived from gonadal ridges of aborted fetuses. The transplant community must strive to uphold societal values in its effort to find remedies for their ailing patients and address the perennial problem of organ shortage. Transplanters also have a responsibility to engage the public in their efforts to gain public understanding and support, and policy makers must take into account public opinion. Only in this way can we realize the great potential of stem cell research for organ transplantation.

Cryopreservation of Human Stem Cells for Clinical Application: A Review

PubMed Central

Hunt, Charles J.

2011-01-01

Summary Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell. PMID:21566712

Cryopreservation of Human Stem Cells for Clinical Application: A Review.

PubMed

Hunt, Charles J

2011-01-01

SUMMARY: Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell.

Matrix mechanics and fluid shear stress control stem cells fate in three dimensional microenvironment.

PubMed

Chen, Guobao; Lv, Yonggang; Guo, Pan; Lin, Chongwen; Zhang, Xiaomei; Yang, Li; Xu, Zhiling

2013-07-01

Stem cells have the ability to self-renew and to differentiate into multiple mature cell types during early life and growth. Stem cells adhesion, proliferation, migration and differentiation are affected by biochemical, mechanical and physical surface properties of the surrounding matrix in which stem cells reside and stem cells can sensitively feel and respond to the microenvironment of this matrix. More and more researches have proven that three dimensional (3D) culture can reduce the gap between cell culture and physiological environment where cells always live in vivo. This review summarized recent findings on the studies of matrix mechanics that control stem cells (primarily mesenchymal stem cells (MSCs)) fate in 3D environment, including matrix stiffness and extracellular matrix (ECM) stiffness. Considering the exchange of oxygen and nutrients in 3D culture, the effect of fluid shear stress (FSS) on fate decision of stem cells was also discussed in detail. Further, the difference of MSCs response to matrix stiffness between two dimensional (2D) and 3D conditions was compared. Finally, the mechanism of mechanotransduction of stem cells activated by matrix mechanics and FSS in 3D culture was briefly pointed out.

Tracking the rise of stem cell tourism.

PubMed

Ryan, Kirsten A; Sanders, Amanda N; Wang, Dong D; Levine, Aaron D

2010-01-01

Driven by hype surrounding stem cell research, a number of clinics around the world currently offer 'stem cell therapies' to patients. These unproven interventions have attracted policy interest owing to the risks they may pose to patients and to the progress of legitimate translational stem cell research, yet remarkably little data exists about the patients who undergo these unproven therapies or their experiences. We sought to characterize this patient population. We developed a comprehensive data set of blogs written by patients (or their caretakers) about their experiences with unproven stem cell therapies. Analyzing these data suggests that unproven stem cell therapies are increasing rapidly in popularity and are attracting a wide range of patients--both young and old and with a diverse collection of medical conditions. These results should help clinicians advise individual patients and help policymakers devise strategies to mitigate the risks these treatments pose.

Debating restrictions on embryonic stem cell research.

PubMed

McClain, Colleen

2009-09-01

This study investigates the emotional and behavioral effects of interpersonal online communication, focusing on the controversy surrounding the loosening of restrictions on human embryonic stem cell research. The issue, central to national and statewide elections in 2008, generated heated debate among candidates and voters and evoked strong emotional sentiments among partisans. Using the theory of affective intelligence, this study proposes a predictive model connecting levels of enthusiasm and anxiety with behavioral and information-seeking outcomes. Cognitive appraisal theory is also employed to provide a role for political emotion in accounting for interactive media effects. To investigate the ways that online deliberation may influence discussions surrounding stem cell research, a between-subjects experimental study was conducted that systematically varied the tone of feedback received (reinforcing or challenging) and type of interaction (synchronous or asynchronous) experienced by users. Results indicate that emotional responses play a significant role in predicting behavioral intentions arising from the user-to-user interactive experience.

Regenerative Chemical Biology: Current Challenges and Future Potential

PubMed Central

Ao, Ada; Hao, Jijun; Hong, Charles C.

2011-01-01

The enthusiasm surrounding the clinical potential of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) is tempered by the fact that key issues regarding their safety, efficacy, and long-term benefits have thus far been suboptimal. Small molecules can potentially relieve these problems at major junctions of stem cell biology and regenerative therapy. In this review, we will introduce recent advances in these important areas and the first-generation of small molecules used in the regenerative context. Current chemical biology studies will provide the archetype for future interdisciplinary collaborations, and improve clinical benefits of cell-based therapies. PMID:21513877

Stem cell banking: between traceability and identifiability

PubMed Central

2010-01-01

Stem cell banks are increasingly seen as an essential resource of biological materials for both basic and translational research. Stem cell banks support transnational access to quality-controlled and ethically sourced stem cell lines from different origins and of varying grades. According to the Organisation for Economic Co-operation and Development, advances in regenerative medicine are leading to the development of a bioeconomy, 'a world where biotechnology contributes to a significant share of economic output'. Consequently, stem cell banks are destined to constitute a pillar of the bioeconomy in many countries. While certain ethical and legal concerns are specific to the nature of stem cells, stem cell banking could do well to examine the approaches fostered by tissue banking generally. Indeed, the past decade has seen a move to simplify and harmonize biological tissue and data banking so as to foster international interoperability. In particular, the issues of consent and of traceability illustrate not only commonalities but the opportunity for stem cell banking to appreciate the lessons learned in biobanking generally. This paper analyzes convergence and divergence in issues surrounding policy harmonization, transnational sharing, informed consent, traceability and return of results in the context of stem cell banks. PMID:20923580

Optimal matrix rigidity for stress fiber polarization in stem cells

PubMed Central

Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.

2010-01-01

The shape and differentiation of human mesenchymal stem cells is especially sensitive to the rigidity of their environment; the physical mechanisms involved are unknown. A theoretical model and experiments demonstrate here that the polarization/alignment of stress-fibers within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix whose polarizability, unlike dead matter, depends on the feedback of cellular forces that develop in response to matrix stresses. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress-fibers parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress-fibers in stem cells. These findings offer a first physical insight for the dependence of stem cell differentiation on tissue elasticity. PMID:20563235

Neural stem cells induce the formation of their physical niche during organogenesis

PubMed Central

Riebesehl, Bea F; Ambrosio, Elizabeth M; Stolper, Julian S; Lischik, Colin Q; Dross, Nicolas

2017-01-01

Most organs rely on stem cells to maintain homeostasis during post-embryonic life. Typically, stem cells of independent lineages work coordinately within mature organs to ensure proper ratios of cell types. Little is known, however, on how these different stem cells locate to forming organs during development. Here we show that neuromasts of the posterior lateral line in medaka are composed of two independent life-long lineages with different embryonic origins. Clonal analysis and 4D imaging revealed a hierarchical organisation with instructing and responding roles: an inner, neural lineage induces the formation of an outer, border cell lineage (nBC) from the skin epithelium. Our results demonstrate that the neural lineage is necessary and sufficient to generate nBCs highlighting self-organisation principles at the level of the entire embryo. We hypothesise that induction of surrounding tissues plays a major role during the establishment of vertebrate stem cell niches. PMID:28950935

ERRATUM: In vivo evaluation of a neural stem cell-seeded prosthesis In vivo evaluation of a neural stem cell-seeded prosthesis

NASA Astrophysics Data System (ADS)

Purcell, E. K.; Seymour, J. P.; Yandamuri, S.; Kipke, D. R.

2009-08-01

In the published article, an error was made in figure 5. Specifically, the three-month, NSC-seeded image is a duplicate of the six-week image, and the one-day, probe alone image is a duplicate of the three-month image. The corrected figure is reproduced below. Figure 5 Figure 5. Glial encapsulation of each probe condition over the 3 month time course. Ox-42 labeled microglia and GFAP labeled astrocytes are shown. Images are taken from probes implanted in the same animal at each time point. NSC seeding was associated with reduced non-neuronal density at 1 day post-implantation in comparison to alginate coated probes and at the 1 week time point in comparison to untreated probes (P < 0.001). Glial activation is at its overall peak 1 week after insertion. A thin encapsulation layer surrounds probes at the 6 week and 3 month time points, with NSC-seeded probes having the greatest surrounding non-neuronal density P < 0.001). Interestingly, microglia appeared to have a ramified, or `surveilling', morphology surrounding a neural stem cell-alginate probe initially, whereas activated cells with an amoeboid structure were found near an alginate probe in the same hemisphere of one animal (left panels).

Science spin: iPS cell research in the news.

PubMed

Caulfield, T; Rachul, C

2011-05-01

Big scientific developments have always been spun to meet particular social agendas. We have seen it in the context of global warming, nuclear power, and genetically modified organisms. But few stories illustrate the phenomenon of spin as well as the reaction, and concomitant media coverage, that surrounded the November 2007 announcement regarding the reprogramming of skin cells to produce cells with qualities comparable to those of human embryonic stem cells (hESCs) known as induced pluripotent stem (iPS) cells.

Future issues in transplantation ethics: ethical and legal controversies in xenotransplantation, stem cell, and cloning research.

PubMed

Shapiro, Robyn S

2008-07-01

With little prospect of developing a sufficient supply of human transplantable organs to meet the large and growing demand, attention has turned to xenotransplantation, as well as stem cell and cloning research, as possible approaches for alleviating this allograft shortage. This article explores ethical and legal issues that surround developments in these fields.

Nanotopographical Surfaces for Stem Cell Fate Control: Engineering Mechanobiology from the Bottom

PubMed Central

Chen, Weiqiang; Shao, Yue; Li, Xiang; Zhao, Gang; Fu, Jianping

2015-01-01

Summary During embryogenesis and tissue maintenance and repair in an adult organism, a myriad of stem cells are regulated by their surrounding extracellular matrix (ECM) enriched with tissue/organ-specific nanoscale topographical cues to adopt different fates and functions. Attributed to their capability of self-renewal and differentiation into most types of somatic cells, stem cells also hold tremendous promise for regenerative medicine and drug screening. However, a major challenge remains as to achieve fate control of stem cells in vitro with high specificity and yield. Recent exciting advances in nanotechnology and materials science have enabled versatile, robust, and large-scale stem cell engineering in vitro through developments of synthetic nanotopographical surfaces mimicking topological features of stem cell niches. In addition to generating new insights for stem cell biology and embryonic development, this effort opens up unlimited opportunities for innovations in stem cell-based applications. This review is therefore to provide a summary of recent progress along this research direction, with perspectives focusing on emerging methods for generating nanotopographical surfaces and their applications in stem cell research. Furthermore, we provide a review of classical as well as emerging cellular mechano-sensing and -transduction mechanisms underlying stem cell nanotopography sensitivity and also give some hypotheses in regard to how a multitude of signaling events in cellular mechanotransduction may converge and be integrated into core pathways controlling stem cell fate in response to extracellular nanotopography. PMID:25883674

Stem-cell-activated organ following ultrasound exposure: better transplant option for organ transplantation.

PubMed

Wang, Sen; Li, Yu; Ji, Ying-Chang; Lin, Chang-Min; Man, Cheng; Zheng, Xiao-Xuan

2010-01-01

Although doctors try their best to protect transplants during surgery, there remain great challenges for the higher survival rate and less rejection of transplants after organ transplantation. Growing evidence indicates that the stem cells could function after injury rather than aging, implying that suitable injury may activate the stem cells of damaged organs. Furthermore, it has been revealed that stem cells can be used to induce tolerance in transplantation and the ultrasound has great biological effects on organs. Basing on these facts, we hypothesize that the stem cells within the transplants can be activated by ultrasound with high-frequency and medium-intensity. Therefore, the stem-cell-activated organs (SCAO) can be derived, and the SCAO will be better transplant option for organ transplantation. We postulate the ultrasound can change the molecular activity and/or quantity of the stem cells, the membrane permeability, the cell-cell junctions, and their surrounding microenvironments. As a result, the stem cells are activated, and the SCAO will acquire more regenerative capacity and less rejection. In the paper, we also discuss the process, methods and models for verifying the theory, and the consequences. We believe the theory may provide a practical method for the clinical application of the ultrasound and stem cells in organ transplantation.

Insight on stem cell preconditioning and instructive biomaterials to enhance cell adhesion, retention, and engraftment for tissue repair.

PubMed

Shafiq, Muhammad; Jung, Youngmee; Kim, Soo Hyun

2016-06-01

Stem cells are a promising solution for the treatment of a variety of diseases. However, the limited survival and engraftment of transplanted cells due to a hostile ischemic environment is a bottleneck for effective utilization and commercialization. Within this environment, the majority of transplanted cells undergo apoptosis prior to participating in lineage differentiation and cellular integration. Therefore, in order to maximize the clinical utility of stem/progenitor cells, strategies must be employed to increase their adhesion, retention, and engraftment in vivo. Here, we reviewed key strategies that are being adopted to enhance the survival, retention, and engraftment of transplanted stem cells through the manipulation of both the stem cells and the surrounding environment. We describe how preconditioning of cells or cell manipulations strategies can enhance stem cell survival and engraftment after transplantation. We also discuss how biomaterials can enhance the function of stem cells for effective tissue regeneration. Biomaterials can incorporate or mimic extracellular function (ECM) function and enhance survival or differentiation of transplanted cells in vivo. Biomaterials can also promote angiogenesis, enhance engraftment and differentiation, and accelerate electromechanical integration of transplanted stem cells. Insight gained from this review may direct the development of future investigations and clinical trials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gliomagenesis and neural stem cells: Key role of hypoxia and concept of tumor "neo-niche".

PubMed

Diabira, Sylma; Morandi, Xavier

2008-01-01

Gliomas represent the most common primary brain tumors and the most devastating pathology of the central nervous system. Despite progress in conventional treatments, the prognosis remains dismal. Recent studies have suggested that a glioma brain tumor may arise from a "cancer stem cell". To understand this theory we summarize studies of the concepts of neural stem cell, and its specialized microenvironment, namely the niche which can regulate balanced self-renewal, differentiation and stem cell quiescence. We summarize the molecular mechanism known or postulated to be involved in the disregulation of normal stem cells features allowing them to undergo neoplasic transformation. We seek data pointing out the key role of hypoxia in normal homeostasis of stem cells and in the initiation, development and aggressiveness of gliomas. We develop the concept of tumor special microenvironment and we propose the new concept of neo-niche, surrounding the glioma, in which hypoxia could be a key factor to recruit and deregulate different stem cells for gliogenesis process. Substantial advances in treatment would come from obtaining better knowledge of molecular impairs of this disease.

Biophysics and dynamics of natural and engineered stem cell microenvironments.

PubMed

Keung, Albert J; Healy, Kevin E; Kumar, Sanjay; Schaffer, David V

2010-01-01

Stem cells are defined by their ability to self-renew and to differentiate into one or more mature lineages, and they reside within natural niches in many types of adult and embryonic tissues that present them with complex signals to regulate these two hallmark properties. The diverse nature of these in vivo microenvironments raises important questions about the microenvironmental cues regulating stem cell plasticity, and the stem cell field has built a strong foundation of knowledge on the biochemical identities and regulatory effects of the soluble, cellular, and extracellular matrix factors surrounding stem cells through the isolation and culture of stem cells in vitro within microenvironments that, in effect, emulate the properties of the natural niche. Recent work, however, has expanded the field's perspective to include biophysical and dynamic characteristics of the microenvironment. These include biomechanical characteristics such as elastic modulus, shear force, and cyclic strain; architectural properties such as geometry, topography, and dimensionality; and dynamic structures and ligand profiles. We will review how these microenvironmental characteristics have been shown to regulate stem cell fate and discuss future research directions that may help expand our current understanding of stem cell biology and aid its application to regenerative medicine.

Biomaterials for 4D stem cell culture

PubMed Central

Hilderbrand, Amber M.; Ovadia, Elisa M.; Rehmann, Matthew S.; Kharkar, Prathamesh M.; Guo, Chen; Kloxin, April M.

2017-01-01

Stem cells reside in complex three-dimensional (3D) environments within the body that change with time, promoting various cellular functions and processes such as migration and differentiation. These complex changes in the surrounding environment dictate cell fate yet, until recently, have been challenging to mimic within cell culture systems. Hydrogel-based biomaterials are well suited to mimic aspects of these in vivo environments, owing to their high water content, soft tissue-like elasticity, and often-tunable biochemical content. Further, hydrogels can be engineered to achieve changes in matrix properties over time to better mimic dynamic native microenvironments for probing and directing stem cell function and fate. This review will focus on techniques to form hydrogel-based biomaterials and modify their properties in time during cell culture using select addition reactions, cleavage reactions, or non-covalent interactions. Recent applications of these techniques for the culture of stem cells in four dimensions (i.e., in three dimensions with changes over time) also will be discussed for studying essential stem cell processes. PMID:28717344

Fully functional hair follicle regeneration through the rearrangement of stem cells and their niches

PubMed Central

Toyoshima, Koh-ei; Asakawa, Kyosuke; Ishibashi, Naoko; Toki, Hiroshi; Ogawa, Miho; Hasegawa, Tomoko; Irié, Tarou; Tachikawa, Tetsuhiko; Sato, Akio; Takeda, Akira; Tsuji, Takashi

2012-01-01

Organ replacement regenerative therapy is purported to enable the replacement of organs damaged by disease, injury or aging in the foreseeable future. Here we demonstrate fully functional hair organ regeneration via the intracutaneous transplantation of a bioengineered pelage and vibrissa follicle germ. The pelage and vibrissae are reconstituted with embryonic skin-derived cells and adult vibrissa stem cell region-derived cells, respectively. The bioengineered hair follicle develops the correct structures and forms proper connections with surrounding host tissues such as the epidermis, arrector pili muscle and nerve fibres. The bioengineered follicles also show restored hair cycles and piloerection through the rearrangement of follicular stem cells and their niches. This study thus reveals the potential applications of adult tissue-derived follicular stem cells as a bioengineered organ replacement therapy. PMID:22510689

Expression of Idh1R132H in the Murine Subventricular Zone Stem Cell Niche Recapitulates Features of Early Gliomagenesis.

PubMed

Bardella, Chiara; Al-Dalahmah, Osama; Krell, Daniel; Brazauskas, Pijus; Al-Qahtani, Khalid; Tomkova, Marketa; Adam, Julie; Serres, Sébastien; Lockstone, Helen; Freeman-Mills, Luke; Pfeffer, Inga; Sibson, Nicola; Goldin, Robert; Schuster-Böeckler, Benjamin; Pollard, Patrick J; Soga, Tomoyoshi; McCullagh, James S; Schofield, Christopher J; Mulholland, Paul; Ansorge, Olaf; Kriaucionis, Skirmantas; Ratcliffe, Peter J; Szele, Francis G; Tomlinson, Ian

2016-10-10

Isocitrate dehydrogenase 1 mutations drive human gliomagenesis, probably through neomorphic enzyme activity that produces D-2-hydroxyglutarate. To model this disease, we conditionally expressed Idh1 R132H in the subventricular zone (SVZ) of the adult mouse brain. The mice developed hydrocephalus and grossly dilated lateral ventricles, with accumulation of 2-hydroxyglutarate and reduced α-ketoglutarate. Stem and transit amplifying/progenitor cell populations were expanded, and proliferation increased. Cells expressing SVZ markers infiltrated surrounding brain regions. SVZ cells also gave rise to proliferative subventricular nodules. DNA methylation was globally increased, while hydroxymethylation was decreased. Mutant SVZ cells overexpressed Wnt, cell-cycle and stem cell genes, and shared an expression signature with human gliomas. Idh1 R132H mutation in the major adult neurogenic stem cell niche causes a phenotype resembling gliomagenesis. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

APETALA2 regulates the stem cell niche in the Arabidopsis shoot meristem.

PubMed

Würschum, Tobias; Gross-Hardt, Rita; Laux, Thomas

2006-02-01

Postembryonic organ formation in higher plants relies on the activity of stem cell niches in shoot and root meristems where differentiation of the resident cells is repressed by signals from surrounding cells. We searched for mutations affecting stem cell maintenance and isolated the semidominant l28 mutant, which displays premature termination of the shoot meristem and differentiation of the stem cells. Allele competition experiments suggest that l28 is a dominant-negative allele of the APETALA2 (AP2) gene, which previously has been implicated in floral patterning and seed development. Expression of both WUSCHEL (WUS) and CLAVATA3 (CLV3) genes, which regulate stem cell maintenance in the wild type, were disrupted in l28 shoot apices from early stages on. Unlike in floral patterning, AP2 mRNA is active in the center of the shoot meristem and acts via a mechanism independent of AGAMOUS, which is a repressor of WUS and stem cell maintenance in the floral meristem. Genetic analysis shows that termination of the primary shoot meristem in l28 mutants requires an active CLV signaling pathway, indicating that AP2 functions in stem cell maintenance by modifying the WUS-CLV3 feedback loop.

Isolation and morphology of Stem Cells from Deciduous Tooth (SHED) and Human Dental Pulp Stem Cells (hDPSC)

NASA Astrophysics Data System (ADS)

Ariffin, Shahrul Hisham Zainal; Manogaran, Thanaletchumi; Abidin, Intan Zarina Zainol; Senafi, Sahidan; Wahab, Rohaya Megat Abdul

2016-11-01

Dental pulp is a tissue obtained from pulp chamber of deciduous and permanent tooth which contain stem cells. Stem cell isolation procedure is performed to obtain cells from tissue using enzymatic digestion. The aim of this study is to isolate and observe the morphology of stem cells during passage 0 and passage 3. Dental pulp from deciduous and permanent tooth was enzymatically digested using collagenase Type I and cells obtained were cultured in DMEM-KO that contains 10% fetal bovine serum, 1% antibiotic-antimycotic solution and 0.001× GlutaMax®. During culture, cell morphology was observed under the microscope on day 3, 16 and 33 and captured using cellB software. Giemsa staining was conducted on cells at passage 3. Cells attached at the bottom of the flask on day 3 and started forming small colonies. Cells became confluent after approximately 4 weeks. Both Stem Cells from Deciduous Tooth (SHED) and Human Dental Pulp Stem Cells (hDPSC) exhibited fibroblast-like morphology during passage 0 and passage 3. Meanwhile, Giemsa staining at passage 3 revealed single intact nucleus surrounded by fibroblastic cytoplasm structure. It can be concluded that SHED and hDPSC showed consistent fibroblast-like morphology throughout culture period.

[Current progress and future direction in the biology of ovarian germ stem cells in mammals].

PubMed

Li, Chao-Hui; Guo, Kun; Zheng, Ping

2012-12-01

Whether or not oogenesis continues after birth in mammalian ovaries remains controversial. Since the 1950's, it has been generally accepted that oogenesis takes place during embryogenesis in mammals and ceases at birth. At birth, germ cells in mammalian ovaries have progressed to the diplotene stage of meiotic prophase and have formed primordial follicles with surrounding somatic cells. These primordial follicles represent follicle reserves of the reproductive life. However, this view has been recently challenged by a growing body of evidence showing the isolation and propagation of germ stem cells from mouse and human ovaries. These ovarian germ stem cells are capable of regenerating functional oocytes when transplanted back into recipient ovaries. Despite the discovery of the potential germ stem cells in mammalian ovaries, it remains uncertain whether these cells exist and function in ovaries under physiological conditions. Herein we review the current progress and future direction in this infant area.

Angiopellosis as an Alternative Mechanism of Cell Extravasation.

PubMed

Allen, Tyler A; Gracieux, David; Talib, Maliha; Tokarz, Debra A; Hensley, M Taylor; Cores, Jhon; Vandergriff, Adam; Tang, Junnan; de Andrade, James B M; Dinh, Phuong-Uyen; Yoder, Jeffrey A; Cheng, Ke

2017-01-01

Stem cells possess the ability to home in and travel to damaged tissue when injected intravenously. For the cells to exert their therapeutic effect, they must cross the blood vessel wall and enter the surrounding tissues. The mechanism of extravasation injected stem cells employ for exit has yet to be characterized. Using intravital microscopy and a transgenic zebrafish line Tg(fli1a:egpf) with GFP-expressing vasculature, we documented the detailed extravasation processes in vivo for injected stem cells in comparison to white blood cells (WBCs). While WBCs left the blood vessels by the standard diapedesis process, injected cardiac and mesenchymal stem cells underwent a distinct method of extravasation that was markedly different from diapedesis. Here, the vascular wall undergoes an extensive remodeling to allow the cell to exit the lumen, while the injected cell remains distinctively passive in activity. We termed this process Angio-pello-sis, which represents an alternative mechanism of cell extravasation to the prevailing theory of diapedesis. Stem Cells 2017;35:170-180 Video Highlight: https://youtu.be/i5EI-ZvhBps. © 2016 AlphaMed Press.

Sucrose accumulation in sweet sorghum stems occurs by apoplasmic phloem unloading and does not involve differential Sucrose transporter expression.

PubMed

Bihmidine, Saadia; Baker, R Frank; Hoffner, Cassandra; Braun, David M

2015-07-30

Sorghum (Sorghum bicolor L. Moench) cultivars store non-structural carbohydrates predominantly as either starch in seeds (grain sorghums) or sugars in stems (sweet sorghums). Previous research determined that sucrose accumulation in sweet sorghum stems was not correlated with the activities of enzymes functioning in sucrose metabolism, and that an apoplasmic transport step may be involved in stem sucrose accumulation. However, the sucrose unloading pathway from stem phloem to storage parenchyma cells remains unelucidated. Sucrose transporters (SUTs) transport sucrose across membranes, and have been proposed to function in sucrose partitioning differences between sweet and grain sorghums. The purpose of this study was to characterize the key differences in carbohydrate accumulation between a sweet and a grain sorghum, to define the path sucrose may follow for accumulation in sorghum stems, and to determine the roles played by sorghum SUTs in stem sucrose accumulation. Dye tracer studies to determine the sucrose transport route revealed that, for both the sweet sorghum cultivar Wray and grain sorghum cultivar Macia, the phloem in the stem veins was symplasmically isolated from surrounding cells, suggesting sucrose was apoplasmically unloaded. Once in the phloem apoplasm, a soluble tracer diffused from the vein to stem parenchyma cell walls, indicating the lignified mestome sheath encompassing the vein did not prevent apoplasmic flux outside of the vein. To characterize carbohydrate partitioning differences between Wray and Macia, we compared the growth, stem juice volume, solute contents, SbSUTs gene expression, and additional traits. Contrary to previous findings, we detected no significant differences in SbSUTs gene expression within stem tissues. Phloem sieve tubes within sweet and grain sorghum stems are symplasmically isolated from surrounding cells; hence, unloading from the phloem likely occurs apoplasmically, thereby defining the location of the previously postulated step for sucrose transport. Additionally, no changes in SbSUTs gene expression were detected in sweet vs. grain sorghum stems, suggesting alterations in SbSUT transcript levels do not account for the carbohydrate partitioning differences between cultivars. A model illustrating sucrose phloem unloading and movement to stem storage parenchyma, and highlighting roles for sucrose transport proteins in sorghum stems is discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bihmidine, Saadia; Baker, R. Frank; Hoffner, Cassandra

Background: Sorghum (Sorghum bicolor L. Moench) cultivars store non-structural carbohydrates predominantly as either starch in seeds (grain sorghums) or sugars in stems (sweet sorghums). Previous research determined that sucrose accumulation in sweet sorghum stems was not correlated with the activities of enzymes functioning in sucrose metabolism, and that an apoplasmic transport step may be involved in stem sucrose accumulation. However, the sucrose unloading pathway from stem phloem to storage parenchyma cells remains unelucidated. Sucrose transporters (SUTs) transport sucrose across membranes, and have been proposed to function in sucrose partitioning differences between sweet and grain sorghums. The purpose of this studymore » was to characterize the key differences in carbohydrate accumulation between a sweet and a grain sorghum, to define the path sucrose may follow for accumulation in sorghum stems, and to determine the roles played by sorghum SUTs in stem sucrose accumulation. Results: Dye tracer studies to determine the sucrose transport route revealed that, for both the sweet sorghum cultivar Wray and grain sorghum cultivar Macia, the phloem in the stem veins was symplasmically isolated from surrounding cells, suggesting sucrose was apoplasmically unloaded. Once in the phloem apoplasm, a soluble tracer diffused from the vein to stem parenchyma cell walls, indicating the lignified mestome sheath encompassing the vein did not prevent apoplasmic flux outside of the vein. To characterize carbohydrate partitioning differences between Wray and Macia, we compared the growth, stem juice volume, solute contents, SbSUTs gene expression, and additional traits. Contrary to previous findings, we detected no significant differences in SbSUTs gene expression within stem tissues. Conclusions: Phloem sieve tubes within sweet and grain sorghum stems are symplasmically isolated from surrounding cells; hence, unloading from the phloem likely occurs apoplasmically, thereby defining the location of the previously postulated step for sucrose transport. Additionally, no changes in SbSUTs gene expression were detected in sweet vs. grain sorghum stems, suggesting alterations in SbSUT transcript levels do not account for the carbohydrate partitioning differences between cultivars. A model illustrating sucrose phloem unloading and movement to stem storage parenchyma, and highlighting roles for sucrose transport proteins in sorghum stems is discussed.« less

Alternative sources of pluripotency: science, ethics, and stem cells.

PubMed

Kastenberg, Zachary J; Odorico, Jon S

2008-07-01

Despite many advances in human embryonic stem cell (hESC) technology the ethical dilemma involving the destruction of a human embryo is one factor that has limited the development of hESC based clinical therapies. Two recent reports describing the production of pluripotent stem cells following the in vitro reprogramming of human somatic cells with certain defined factors illustrate one potential method of bypassing the ethical debate surrounding hESCs (Yu J, Vodyanik MA, Smuga-Otto K, et al. Induced pluripotent stem cell lines derived from human somatic cells. Science. 2007 Dec;318(5858):1917-1920; Takahashi K, Tanabe K, Ohnuki M, et al. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell. 2007 Nov;131(5): 861-872.). Other alternative methods include nuclear transfer, altered nuclear transfer, and parthenogenesis; each with its own set of advantages and disadvantages. This review discusses recent advances in these technologies with specific focus on the issues of embryo destruction, oocyte recovery, and the potential of each technology to produce large scale, patient specific cell transplantation therapies that would require little or no immunosuppression.

Human Adipose-Derived Stem Cells Labeled with Plasmonic Gold Nanostars for Cellular Tracking and Photothermal Cancer Cell Ablation.

PubMed

Shammas, Ronnie L; Fales, Andrew M; Crawford, Bridget M; Wisdom, Amy J; Devi, Gayathri R; Brown, David A; Vo-Dinh, Tuan; Hollenbeck, Scott T

2017-04-01

Gold nanostars are unique nanoplatforms that can be imaged in real time and transform light energy into heat to ablate cells. Adipose-derived stem cells migrate toward tumor niches in response to chemokines. The ability of adipose-derived stem cells to migrate and integrate into tumors makes them ideal vehicles for the targeted delivery of cancer nanotherapeutics. To test the labeling efficiency of gold nanostars, undifferentiated adipose-derived stem cells were incubated with gold nanostars and a commercially available nanoparticle (Qtracker), then imaged using two-photon photoluminescence microscopy. The effects of gold nanostars on cell phenotype, proliferation, and viability were assessed with flow cytometry, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide metabolic assay, and trypan blue, respectively. Trilineage differentiation of gold nanostar-labeled adipose-derived stem cells was induced with the appropriate media. Photothermolysis was performed on adipose-derived stem cells cultured alone or in co-culture with SKBR3 cancer cells. Efficient uptake of gold nanostars occurred in adipose-derived stem cells, with persistence of the luminescent signal over 4 days. Labeling efficiency and signal quality were greater than with Qtracker. Gold nanostars did not affect cell phenotype, viability, or proliferation, and exhibited stronger luminescence than Qtracker throughout differentiation. Zones of complete ablation surrounding the gold nanostar-labeled adipose-derived stem cells were observed following photothermolysis in both monoculture and co-culture models. Gold nanostars effectively label adipose-derived stem cells without altering cell phenotype. Once labeled, photoactivation of gold nanostar-labeled adipose-derived stem cells ablates neighboring cancer cells, demonstrating the potential of adipose-derived stem cells as a vehicle for the delivery of site-specific cancer therapy.

Toward angiogenesis of implanted bio-artificial liver using scaffolds with type I collagen and adipose tissue-derived stem cells.

PubMed

Lee, Jae Geun; Bak, Seon Young; Nahm, Ji Hae; Lee, Sang Woo; Min, Seon Ok; Kim, Kyung Sik

2015-05-01

Stem cell therapies for liver disease are being studied by many researchers worldwide, but scientific evidence to demonstrate the endocrinologic effects of implanted cells is insufficient, and it is unknown whether implanted cells can function as liver cells. Achieving angiogenesis, arguably the most important characteristic of the liver, is known to be quite difficult, and no practical attempts have been made to achieve this outcome. We carried out this study to observe the possibility of angiogenesis of implanted bio-artificial liver using scaffolds. This study used adipose tissue-derived stem cells that were collected from adult patients with liver diseases with conditions similar to the liver parenchyma. Specifically, microfilaments were used to create an artificial membrane and maintain the structure of an artificial organ. After scratching the stomach surface of severe combined immunocompromised (SCID) mice (n=4), artificial scaffolds with adipose tissue-derived stem cells and type I collagen were implanted. Expression levels of angiogenesis markers including vascular endothelial growth factor (VEGF), CD34, and CD105 were immunohistochemically assessed after 30 days. Grossly, the artificial scaffolds showed adhesion to the stomach and surrounding organs; however, there was no evidence of angiogenesis within the scaffolds; and VEGF, CD34, and CD105 expressions were not detected after 30 days. Although implantation of cells into artificial scaffolds did not facilitate angiogenesis, the artificial scaffolds made with type I collagen helped maintain implanted cells, and surrounding tissue reactions were rare. Our findings indicate that type I collagen artificial scaffolds can be considered as a possible implantable biomaterial.

Surface functionalization of nanobiomaterials for application in stem cell culture, tissue engineering, and regenerative medicine.

PubMed

Rana, Deepti; Ramasamy, Keerthana; Leena, Maria; Jiménez, Constanza; Campos, Javier; Ibarra, Paula; Haidar, Ziyad S; Ramalingam, Murugan

2016-05-01

Stem cell-based approaches offer great application potential in tissue engineering and regenerative medicine owing to their ability of sensing the microenvironment and respond accordingly (dynamic behavior). Recently, the combination of nanobiomaterials with stem cells has paved a great way for further exploration. Nanobiomaterials with engineered surfaces could mimic the native microenvironment to which the seeded stem cells could adhere and migrate. Surface functionalized nanobiomaterial-based scaffolds could then be used to regulate or control the cellular functions to culture stem cells and regenerate damaged tissues or organs. Therefore, controlling the interactions between nanobiomaterials and stem cells is a critical factor. However, surface functionalization or modification techniques has provided an alternative approach for tailoring the nanobiomaterials surface in accordance to the physiological surrounding of a living cells; thereby, enhancing the structural and functional properties of the engineered tissues and organs. Currently, there are a variety of methods and technologies available to modify the surface of biomaterials according to the specific cell or tissue properties to be regenerated. This review highlights the trends in surface modification techniques for nanobiomaterials and the biological relevance in stem cell-based tissue engineering and regenerative medicine. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:554-567, 2016. © 2016 American Institute of Chemical Engineers.

Stem cells and corneal epithelial maintenance – insights from the mouse and other animal models

PubMed Central

Mort, Richard L.; Douvaras, Panagiotis; Morley, Steven D.; Dorà, Natalie; Hill, Robert E.; Collinson, J. Martin; West, John D.

2012-01-01

Maintenance of the corneal epithelium is essential for vision and is a dynamic process incorporating constant cell production, movement and loss. Although cell based therapies involving the transplantation of putative stem cells are well advanced for the treatment of human corneal defects, the scientific understanding of these interventions is poor. No definitive marker that discriminates stem cells that maintain the corneal epithelium from the surrounding tissue has been discovered and the identity of these elusive cells is, therefore, hotly debated. The key elements of corneal epithelial maintenance have long been recognised but it is still not known how this dynamic balance is coordinated during normal homeostasis to ensure the corneal epithelium is maintained at a uniform thickness. Most indirect experimental evidence supports the limbal epithelial stem cell (LESC) hypothesis, which proposes that the adult corneal epithelium is maintained by stem cells located in the limbus at the corneal periphery. However, this has been challenged recently by the corneal epithelial stem cell (CESC) hypothesis, which proposes that during normal homeostasis the mouse corneal epithelium is maintained by stem cells located throughout the basal corneal epithelium with LESCs only contributing during wound healing. In this chapter we review experimental studies, mostly based on animal work, that provide insights into how stem cells maintain the normal corneal epithelium and consider the merits of the alternative LESC and CESC hypotheses. Finally, we highlight some recent research on other stem cell systems and consider how this could influence future research directions for identifying the stem cells that maintain the corneal epithelium. PMID:22918816

Publishing SNP genotypes of human embryonic stem cell lines: policy statement of the International Stem Cell Forum Ethics Working Party.

PubMed

Knoppers, Bartha M; Isasi, Rosario; Benvenisty, Nissim; Kim, Ock-Joo; Lomax, Geoffrey; Morris, Clive; Murray, Thomas H; Lee, Eng Hin; Perry, Margery; Richardson, Genevra; Sipp, Douglas; Tanner, Klaus; Wahlström, Jan; de Wert, Guido; Zeng, Fanyi

2011-09-01

Novel methods and associated tools permitting individual identification in publicly accessible SNP databases have become a debatable issue. There is growing concern that current technical and ethical safeguards to protect the identities of donors could be insufficient. In the context of human embryonic stem cell research, there are no studies focusing on the probability that an hESC line donor could be identified by analyzing published SNP profiles and associated genotypic and phenotypic information. We present the International Stem Cell Forum (ISCF) Ethics Working Party's Policy Statement on "Publishing SNP Genotypes of Human Embryonic Stem Cell Lines (hESC)". The Statement prospectively addresses issues surrounding the publication of genotypic data and associated annotations of hESC lines in open access databases. It proposes a balanced approach between the goals of open science and data sharing with the respect for fundamental bioethical principles (autonomy, privacy, beneficence, justice and research merit and integrity).

Alginate Microcapsules Incorporating Hyaluronic Acid Recreate Closer in Vivo Environment for Mesenchymal Stem Cells.

PubMed

Cañibano-Hernández, Alberto; Saenz Del Burgo, Laura; Espona-Noguera, Albert; Orive, Gorka; Hernández, Rosa M; Ciriza, Jesús; Pedraz, Jose Luis

2017-07-03

The potential clinical application of alginate cell microencapsulation has advanced enormously during the past decade. However, the 3D environment created by alginate beads does not mimic the natural extracellular matrix surrounding cells in vivo, responsible of cell survival and functionality. As one of the most frequent macromolecules present in the extracellular matrix is hyaluronic acid, we have formed hybrid beads with alginate and hyaluronic acid recreating a closer in vivo cell environment. Our results show that 1% alginate-0.25% hyaluronic acid microcapsules retain 1.5% alginate physicochemical properties. Moreover, mesenchymal stem cells encapsulated in these hybrid beads show enhanced viability therapeutic protein release and mesenchymal stem cells' potential to differentiate into chondrogenic lineage. Although future studies with additional proteins need to be done in order to approach even more the extracellular matrix features, we have shown that hyaluronic acid protects alginate encapsulated mesenchymal stem cells by providing a niche-like environment and remaining them competent as a sustainable drug delivery system.

Semiconductor chips, genes, and stem cells: new wine for new bottles?

PubMed

Rose, Simone A

2012-01-01

This Article analogizes early semiconductor technology and its surrounding economics with isolated genes, stem cells, and related bioproducts, and their surrounding economics, to make the case for sui generis (of its own class) intellectual property protection for isolated bioproducts. Just as early semiconductors failed to meet the patent social bargain requiring novelty and non-obviousness in the 1980s, isolated genes and stem cells currently fail to meet the patent bargain requirements of non-obviousness and eligible subject matter that entitle them to traditional intellectual property protection. Like early semiconductor chip designs, nevertheless, the high cost of upstream bioproduct research and development, coupled with the need to sustain continued economic growth of the biotechnology industry, mandates that Congress provide some level of exclusive rights to ensure continued funding for this research. Sui generis intellectual property protection for isolated bioproducts would preserve the incentive to continue innovation in the field. As illustrated by the semiconductor industry, however, such sui generis protection for this technology must include limitations that address the need to provide an appropriate level of public access to facilitate downstream product development and enrich the public domain.

Adeno-Associated Virus Vectors and Stem Cells: Friends or Foes?

PubMed

Brown, Nolan; Song, Liujiang; Kollu, Nageswara R; Hirsch, Matthew L

2017-06-01

The infusion of healthy stem cells into a patient-termed "stem-cell therapy"-has shown great promise for the treatment of genetic and non-genetic diseases, including mucopolysaccharidosis type 1, Parkinson's disease, multiple sclerosis, numerous immunodeficiency disorders, and aplastic anemia. Stem cells for cell therapy can be collected from the patient (autologous) or collected from another "healthy" individual (allogeneic). The use of allogenic stem cells is accompanied with the potentially fatal risk that the transplanted donor T cells will reject the patient's cells-a process termed "graft-versus-host disease." Therefore, the use of autologous stem cells is preferred, at least from the immunological perspective. However, an obvious drawback is that inherently as "self," they contain the disease mutation. As such, autologous cells for use in cell therapies often require genetic "correction" (i.e., gene addition or editing) prior to cell infusion and therefore the requirement for some form of nucleic acid delivery, which sets the stage for the AAV controversy discussed herein. Despite being the most clinically applied gene delivery context to date, unlike other more concerning integrating and non-integrating vectors such as retroviruses and adenovirus, those based on adeno-associated virus (AAV) have not been employed in the clinic. Furthermore, published data regarding AAV vector transduction of stem cells are inconsistent in regards to vector transduction efficiency, while the pendulum swings far in the other direction with demonstrations of AAV vector-induced toxicity in undifferentiated cells. The variation present in the literature examining the transduction efficiency of AAV vectors in stem cells may be due to numerous factors, including inconsistencies in stem-cell collection, cell culture, vector preparation, and/or transduction conditions. This review summarizes the controversy surrounding AAV vector transduction of stem cells, hopefully setting the stage for future elucidation and eventual therapeutic applications.

Drosophila Perlecan Regulates Intestinal Stem Cell Activity via Cell-Matrix Attachment

PubMed Central

You, Jia; Zhang, Yan; Li, Zhouhua; Lou, Zhefeng; Jin, Longjin; Lin, Xinhua

2014-01-01

Summary Stem cells require specialized local microenvironments, termed niches, for normal retention, proliferation, and multipotency. Niches are composed of cells together with their associated extracellular matrix (ECM). Currently, the roles of ECM in regulating niche functions are poorly understood. Here, we demonstrate that Perlecan (Pcan), a highly conserved ECM component, controls intestinal stem cell (ISC) activities and ISC-ECM attachment in Drosophila adult posterior midgut. Loss of Pcan from ISCs, but not other surrounding cells, causes ISCs to detach from underlying ECM, lose their identity, and fail to proliferate. These defects are not a result of a loss of epidermal growth factor receptor (EGFR) or Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling activity but partially depend on integrin signaling activity. We propose that Pcan secreted by ISCs confers niche properties to the adjacent ECM that is required for ISC maintenance of stem cell identity, activity, and anchorage to the niche. PMID:24936464

The quantitative proteomes of human-induced pluripotent stem cells and embryonic stem cells

PubMed Central

Munoz, Javier; Low, Teck Y; Kok, Yee J; Chin, Angela; Frese, Christian K; Ding, Vanessa; Choo, Andre; Heck, Albert J R

2011-01-01

Assessing relevant molecular differences between human-induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) is important, given that such differences may impact their potential therapeutic use. Controversy surrounds recent gene expression studies comparing hiPSCs and hESCs. Here, we present an in-depth quantitative mass spectrometry-based analysis of hESCs, two different hiPSCs and their precursor fibroblast cell lines. Our comparisons confirmed the high similarity of hESCs and hiPSCS at the proteome level as 97.8% of the proteins were found unchanged. Nevertheless, a small group of 58 proteins, mainly related to metabolism, antigen processing and cell adhesion, was found significantly differentially expressed between hiPSCs and hESCs. A comparison of the regulated proteins with previously published transcriptomic studies showed a low overlap, highlighting the emerging notion that differences between both pluripotent cell lines rather reflect experimental conditions than a recurrent molecular signature. PMID:22108792

Femtosecond laser pulses for chemical-free embryonic and mesenchymal stem cell differentiation

NASA Astrophysics Data System (ADS)

Mthunzi, Patience; Dholakia, Kishan; Gunn-Moore, Frank

2011-10-01

Owing to their self renewal and pluripotency properties, stem cells can efficiently advance current therapies in tissue regeneration and/or engineering. Under appropriate culture conditions in vitro, pluripotent stem cells can be primed to differentiate into any cell type some examples including neural, cardiac and blood cells. However, there still remains a pressing necessity to answer the biological questions concerning how stem cell renewal and how differentiation programs are operated and regulated at the genetic level. In stem cell research, an urgent requirement on experimental procedures allowing non-invasive, marker-free observation of growth, proliferation and stability of living stem cells under physiological conditions exists. Femtosecond (fs) laser pulses have been reported to non-invasively deliver exogenous materials, including foreign genetic species into both multipotent and pluripotent stem cells successfully. Through this multi-photon facilitated technique, directly administering fs laser pulses onto the cell plasma membrane induces transient submicrometer holes, thereby promoting cytosolic uptake of the surrounding extracellular matter. To display a chemical-free cell transfection procedure that utilises micro-litre scale volumes of reagents, we report for the first time on 70 % transfection efficiency in ES-E14TG2a cells using the enhanced green fluorescing protein (EGFP) DNA plasmid. We also show how varying the average power output during optical transfection influences cell viability, proliferation and cytotoxicity in embryonic stem cells. The impact of utilizing objective lenses of different numerical aperture (NA) on the optical transfection efficiency in ES-E14TG2a cells is presented. Finally, we report on embryonic and mesenchymal stem cell differentiation. The produced specialized cell types could thereafter be characterized and used for cell based therapies.

The Fountain of Stem Cell-Based Youth? Online Portrayals of Anti-Aging Stem Cell Technologies.

PubMed

Rachul, Christen M; Percec, Ivona; Caulfield, Timothy

2015-08-01

The hype surrounding stem cell science has created a market opportunity for the cosmetic industry. Cosmetic and anti-aging products and treatments that make claims regarding stem cell technology are increasingly popular, despite a lack of evidence for safety and efficacy of such products. This study explores how stem cell-based products and services are portrayed to the public through online sources, in order to gain insight into the key messages available to consumers. A content analysis of 100 web pages was conducted to examine the portrayals of stem cell-based cosmetic and anti-aging products and treatments. A qualitative discourse analysis of one web page further examined how language contributes to the portrayals of these products and treatments to public audiences. The majority of web pages portrayed stem cell-based products as ready for public use. Very few web pages substantiated claims with scientific evidence, and even fewer mentioned any risks or limitations associated with stem cell science. The discourse analysis revealed that the framing and use of metaphor obscures the certainty of the efficacy of and length of time for stem cell-based anti-aging technology to be publicly available. This study highlights the need to educate patients and the public on the current limits of stem cell applications in this context. In addition, generating scientific evidence for stem cell-based anti-aging and aesthetic applications is needed for optimizing benefits and minimizing adverse effects for the public. Having more evidence on efficacy and risks will help to protect patients who are eagerly seeking out these treatments. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Notch ligand Dll1 mediates cross-talk between mammary stem cells and the macrophageal niche.

PubMed

Chakrabarti, Rumela; Celià-Terrassa, Toni; Kumar, Sushil; Hang, Xiang; Wei, Yong; Choudhury, Abrar; Hwang, Julie; Peng, Jia; Nixon, Briana; Grady, John J; DeCoste, Christina; Gao, Jie; van Es, Johan H; Li, Ming O; Aifantis, Iannis; Clevers, Hans; Kang, Yibin

2018-05-17

The stem cell niche is a specialized environment that dictates stem cell function during development and homeostasis. Here, we show that Dll1, a Notch pathway ligand, is enriched in mammary gland stem cells (MaSCs) and mediates critical interactions with stromal macrophages in the surrounding niche. Conditional deletion of Dll1 reduced the number of MaSCs and impaired ductal morphogenesis in the mammary gland. Moreover, MaSC-expressed Dll1 activates Notch signaling in stromal macrophages, increasing their expression of Wnt family ligands such as Wnt3, Wnt10A, and Wnt16, thereby initiating a feed back loop that promotes the function of Dll1 + MaSCs. Together, these findings reveal functionally important cross-talk between MaSCs and their macrophageal niche through Dll1/Notch-mediated signaling. Copyright © 2018, American Association for the Advancement of Science.

Sucrose accumulation in sweet sorghum stems occurs by apoplasmic phloem unloading and does not involve differential Sucrose transporter expression

DOE PAGES

Bihmidine, Saadia; Baker, R. Frank; Hoffner, Cassandra; ...

2015-07-30

Background: Sorghum (Sorghum bicolor L. Moench) cultivars store non-structural carbohydrates predominantly as either starch in seeds (grain sorghums) or sugars in stems (sweet sorghums). Previous research determined that sucrose accumulation in sweet sorghum stems was not correlated with the activities of enzymes functioning in sucrose metabolism, and that an apoplasmic transport step may be involved in stem sucrose accumulation. However, the sucrose unloading pathway from stem phloem to storage parenchyma cells remains unelucidated. Sucrose transporters (SUTs) transport sucrose across membranes, and have been proposed to function in sucrose partitioning differences between sweet and grain sorghums. The purpose of this studymore » was to characterize the key differences in carbohydrate accumulation between a sweet and a grain sorghum, to define the path sucrose may follow for accumulation in sorghum stems, and to determine the roles played by sorghum SUTs in stem sucrose accumulation. Results: Dye tracer studies to determine the sucrose transport route revealed that, for both the sweet sorghum cultivar Wray and grain sorghum cultivar Macia, the phloem in the stem veins was symplasmically isolated from surrounding cells, suggesting sucrose was apoplasmically unloaded. Once in the phloem apoplasm, a soluble tracer diffused from the vein to stem parenchyma cell walls, indicating the lignified mestome sheath encompassing the vein did not prevent apoplasmic flux outside of the vein. To characterize carbohydrate partitioning differences between Wray and Macia, we compared the growth, stem juice volume, solute contents, SbSUTs gene expression, and additional traits. Contrary to previous findings, we detected no significant differences in SbSUTs gene expression within stem tissues. Conclusions: Phloem sieve tubes within sweet and grain sorghum stems are symplasmically isolated from surrounding cells; hence, unloading from the phloem likely occurs apoplasmically, thereby defining the location of the previously postulated step for sucrose transport. Additionally, no changes in SbSUTs gene expression were detected in sweet vs. grain sorghum stems, suggesting alterations in SbSUT transcript levels do not account for the carbohydrate partitioning differences between cultivars. A model illustrating sucrose phloem unloading and movement to stem storage parenchyma, and highlighting roles for sucrose transport proteins in sorghum stems is discussed.« less

Toward angiogenesis of implanted bio-artificial liver using scaffolds with type I collagen and adipose tissue-derived stem cells

PubMed Central

Lee, Jae Geun; Bak, Seon Young; Nahm, Ji Hae; Lee, Sang Woo; Min, Seon Ok

2015-01-01

Backgrounds/Aims Stem cell therapies for liver disease are being studied by many researchers worldwide, but scientific evidence to demonstrate the endocrinologic effects of implanted cells is insufficient, and it is unknown whether implanted cells can function as liver cells. Achieving angiogenesis, arguably the most important characteristic of the liver, is known to be quite difficult, and no practical attempts have been made to achieve this outcome. We carried out this study to observe the possibility of angiogenesis of implanted bio-artificial liver using scaffolds. Methods This study used adipose tissue-derived stem cells that were collected from adult patients with liver diseases with conditions similar to the liver parenchyma. Specifically, microfilaments were used to create an artificial membrane and maintain the structure of an artificial organ. After scratching the stomach surface of severe combined immunocompromised (SCID) mice (n=4), artificial scaffolds with adipose tissue-derived stem cells and type I collagen were implanted. Expression levels of angiogenesis markers including vascular endothelial growth factor (VEGF), CD34, and CD105 were immunohistochemically assessed after 30 days. Results Grossly, the artificial scaffolds showed adhesion to the stomach and surrounding organs; however, there was no evidence of angiogenesis within the scaffolds; and VEGF, CD34, and CD105 expressions were not detected after 30 days. Conclusions Although implantation of cells into artificial scaffolds did not facilitate angiogenesis, the artificial scaffolds made with type I collagen helped maintain implanted cells, and surrounding tissue reactions were rare. Our findings indicate that type I collagen artificial scaffolds can be considered as a possible implantable biomaterial. PMID:26155277

Potential Use of Human Periapical Cyst-Mesenchymal Stem Cells (hPCy-MSCs) as a Novel Stem Cell Source for Regenerative Medicine Applications

PubMed Central

Tatullo, Marco; Codispoti, Bruna; Pacifici, Andrea; Palmieri, Francesca; Marrelli, Massimo; Pacifici, Luciano; Paduano, Francesco

2017-01-01

Mesenchymal stem cells (MSCs) are attracting growing interest by the scientific community due to their huge regenerative potential. Thus, the plasticity of MSCs strongly suggests the utilization of these cells for regenerative medicine applications. The main issue about the clinical use of MSCs is related to the complex way to obtain them from healthy tissues; this topic has encouraged scientists to search for novel and more advantageous sources of these cells in easily accessible tissues. The oral cavity hosts several cell populations expressing mesenchymal stem cell like-features, furthermore, the access to oral and dental tissues is simple and isolation of cells is very efficient. Thus, oral-derived stem cells are highly attractive for clinical purposes. In this context, human periapical cyst mesenchymal stem cells (hPCy-MSCs) exhibit characteristics similar to other dental-derived MSCs, including their extensive proliferative potential, cell surface marker profile and the ability to differentiate into various cell types such as osteoblasts, adipocytes and neurons. Importantly, hPCy-MSCs are easily collected from the surgically removed periapical cysts; this reusing of biological waste guarantees a smart source of stem cells without any impact on the surrounding healthy tissues. In this review, we report the most interesting research topics related to hPCy-MSCs with a newsworthy discussion about the future insights. This newly discovered cell population exhibits interesting and valuable potentialities that could be of high impact in the future regenerative medicine applications. PMID:29259970

Potential Use of Human Periapical Cyst-Mesenchymal Stem Cells (hPCy-MSCs) as a Novel Stem Cell Source for Regenerative Medicine Applications.

PubMed

Tatullo, Marco; Codispoti, Bruna; Pacifici, Andrea; Palmieri, Francesca; Marrelli, Massimo; Pacifici, Luciano; Paduano, Francesco

2017-01-01

Mesenchymal stem cells (MSCs) are attracting growing interest by the scientific community due to their huge regenerative potential. Thus, the plasticity of MSCs strongly suggests the utilization of these cells for regenerative medicine applications. The main issue about the clinical use of MSCs is related to the complex way to obtain them from healthy tissues; this topic has encouraged scientists to search for novel and more advantageous sources of these cells in easily accessible tissues. The oral cavity hosts several cell populations expressing mesenchymal stem cell like-features, furthermore, the access to oral and dental tissues is simple and isolation of cells is very efficient. Thus, oral-derived stem cells are highly attractive for clinical purposes. In this context, human periapical cyst mesenchymal stem cells (hPCy-MSCs) exhibit characteristics similar to other dental-derived MSCs, including their extensive proliferative potential, cell surface marker profile and the ability to differentiate into various cell types such as osteoblasts, adipocytes and neurons. Importantly, hPCy-MSCs are easily collected from the surgically removed periapical cysts; this reusing of biological waste guarantees a smart source of stem cells without any impact on the surrounding healthy tissues. In this review, we report the most interesting research topics related to hPCy-MSCs with a newsworthy discussion about the future insights. This newly discovered cell population exhibits interesting and valuable potentialities that could be of high impact in the future regenerative medicine applications.

Cu2+ inhibition of gel secretion in the xylem and its potential implications for water uptake of cut Acacia holosericea stems.

PubMed

Ratnayake, Kamani; Joyce, Daryl C; Webb, Richard I

2013-08-01

Maintaining a high rate of water uptake is crucial for maximum longevity of cut stems. Physiological gel/tylosis formation decreases water transport efficiency in the xylem. The primary mechanism of action for post-harvest Cu(2+) treatments in improving cut flower and foliage longevity has been elusive. The effect of Cu(2+) on wound-induced xylem vessel occlusion was investigated for Acacia holosericea A. Cunn. ex G. Don. Experiments were conducted using a Cu(2+) pulse (5 h, 2.2 mM) and a Cu(2+) vase solution (0.5 mM) vs a deionized water (DIW) control. Development of xylem blockage in the stem-end region 10 mm proximal to the wounded stem surface was examined over 21 days by light and transmission electron microscopy. Xylem vessels of stems stood into DIW were occluded with gels secreted into vessel lumens via pits from surrounding axial parenchyma cells. Gel secretion was initiated within 1-2 days post-wounding and gels were detected in the xylem from day 3. In contrast, Cu(2+) treatments disrupted the surrounding parenchyma cells, thereby inhibiting gel secretion and maintaining the vessel lumens devoid of occlusions. The Cu(2+) treatments significantly improved water uptake by the cut stems as compared to the control. © 2013 Scandinavian Plant Physiology Society.

In vivo and in vitro evaluation of an Acetobacter xylinum synthesized microbial cellulose membrane intended for guided tissue repair

PubMed Central

Mendes, Péricles Nóbrega; Rahal, Sheila Canevese; Pereira-Junior, Oduvaldo Câmara Marques; Fabris, Viciany Erique; Lenharo, Sara Lais Rahal; de Lima-Neto, João Ferreira; da Cruz Landim-Alvarenga, Fernanda

2009-01-01

Background Barrier materials as cellulose membranes are used for guided tissue repair. However, it is essential that the surrounding tissues accept the device. The present study histologically evaluated tissue reaction to a microbial cellulose membrane after subcutaneous implantation in mice. Furthermore, the interaction between mesenchymal stem cells and the biomaterial was studied in vitro to evaluate its ability to act as cellular scaffold for tissue engineering. Methods Twenty-five Swiss Albino mice were used. A 10 × 10 mm cellulose membrane obtained through biosynthesis using Acetobacter xylinum bacteria was implanted into the lumbar subcutaneous tissue of each mouse. The mice were euthanatized at seven, 15, 30, 60, and 90 days, and the membrane and surrounding tissues were collected and examined by histology. Results A mild inflammatory response without foreign body reaction was observed until 30 days post-surgery around the implanted membrane. Polarized microscopy revealed that the membrane remained intact at all evaluation points. Scanning electron microscopy of the cellulose membrane surface showed absence of pores. The in vitro evaluation of the interaction between cells and biomaterial was performed through viability staining analysis of the cells over the biomaterial, which showed that 95% of the mesenchymal stem cells aggregating to the cellulose membrane were alive and that 5% were necrotic. Scanning electron microscopy showed mesenchymal stem cells with normal morphology and attached to the cellulose membrane surface. Conclusion The microbial cellulose membrane evaluated was found to be nonresorbable, induced a mild inflammatory response and may prove useful as a scaffold for mesenchymal stem cells. PMID:19317903

Biomimetic extracellular matrix mediated somatic stem cell differentiation: applications in dental pulp tissue regeneration

PubMed Central

Ravindran, Sriram; George, Anne

2015-01-01

Dental caries is one of the most widely prevalent infectious diseases in the world. It affects more than half of the world's population. The current treatment for necrotic dental pulp tissue arising from dental caries is root canal therapy. This treatment results in loss of tooth sensitivity and vitality making it prone for secondary infections. Over the past decade, several tissue-engineering approaches have attempted regeneration of the dental pulp tissue. Although several studies have highlighted the potential of dental stem cells, none have transitioned into a clinical setting owing to limited availability of dental stem cells and the need for growth factor delivery systems. Our strategy is to utilize the intact ECM of pulp cells to drive lineage specific differentiation of bone marrow derived mesenchymal stem cells. From a clinical perspective, pulp ECM scaffolds can be generated using cell lines and patient specific somatic stem cells can be used for regeneration. Our published results have shown the feasibility of using pulp ECM scaffolds for odontogenic differentiation of non-dental mesenchymal cells. This focused review discusses the issues surrounding dental pulp tissue regeneration and the potential of our strategy to overcome these issues. PMID:25954205

Gene expression profiling of rat spermatogonia and Sertoli cells reveals signaling pathways from stem cells to niche and testicular cancer cells to surrounding stroma

PubMed Central

2011-01-01

Background Stem cells and their niches are studied in many systems, but mammalian germ stem cells (GSC) and their niches are still poorly understood. In rat testis, spermatogonia and undifferentiated Sertoli cells proliferate before puberty, but at puberty most spermatogonia enter spermatogenesis, and Sertoli cells differentiate to support this program. Thus, pre-pubertal spermatogonia might possess GSC potential and pre-pubertal Sertoli cells niche functions. We hypothesized that the different stem cell pools at pre-puberty and maturity provide a model for the identification of stem cell and niche-specific genes. We compared the transcript profiles of spermatogonia and Sertoli cells from pre-pubertal and pubertal rats and examined how these related to genes expressed in testicular cancers, which might originate from inappropriate communication between GSCs and Sertoli cells. Results The pre-pubertal spermatogonia-specific gene set comprised known stem cell and spermatogonial stem cell (SSC) markers. Similarly, the pre-pubertal Sertoli cell-specific gene set comprised known niche gene transcripts. A large fraction of these specifically enriched transcripts encoded trans-membrane, extra-cellular, and secreted proteins highlighting stem cell to niche communication. Comparing selective gene sets established in this study with published gene expression data of testicular cancers and their stroma, we identified sets expressed genes shared between testicular tumors and pre-pubertal spermatogonia, and tumor stroma and pre-pubertal Sertoli cells with statistic significance. Conclusions Our data suggest that SSC and their niche specifically express complementary factors for cell communication and that the same factors might be implicated in the communication between tumor cells and their micro-enviroment in testicular cancer. PMID:21232125

The Basic Helix-Loop-Helix Transcription Factor MYC2 Directly Represses PLETHORA Expression during Jasmonate-Mediated Modulation of the Root Stem Cell Niche in Arabidopsis[W][OA

PubMed Central

Chen, Qian; Sun, Jiaqiang; Zhai, Qingzhe; Zhou, Wenkun; Qi, Linlin; Xu, Li; Wang, Bao; Chen, Rong; Jiang, Hongling; Qi, Jing; Li, Xugang; Palme, Klaus; Li, Chuanyou

2011-01-01

The root stem cell niche, which in the Arabidopsis thaliana root meristem is an area of four mitotically inactive quiescent cells (QCs) and the surrounding mitotically active stem cells, is critical for root development and growth. We report here that during jasmonate-induced inhibition of primary root growth, jasmonate reduces root meristem activity and leads to irregular QC division and columella stem cell differentiation. Consistently, jasmonate reduces the expression levels of the AP2-domain transcription factors PLETHORA1 (PLT1) and PLT2, which form a developmentally instructive protein gradient and mediate auxin-induced regulation of stem cell niche maintenance. Not surprisingly, the effects of jasmonate on root stem cell niche maintenance and PLT expression require the functioning of MYC2/JASMONATE INSENSITIVE1, a basic helix-loop-helix transcription factor that involves versatile aspects of jasmonate-regulated gene expression. Gel shift and chromatin immunoprecipitation experiments reveal that MYC2 directly binds the promoters of PLT1 and PLT2 and represses their expression. We propose that MYC2-mediated repression of PLT expression integrates jasmonate action into the auxin pathway in regulating root meristem activity and stem cell niche maintenance. This study illustrates a molecular framework for jasmonate-induced inhibition of root growth through interaction with the growth regulator auxin. PMID:21954460

Rare complications after second hematopoietic stem cell transplantation for thalassemia major.

PubMed

Yanir, Asaf; Yatsiv, Ido; Braun, Jacques; Zilkha, Amir; Brooks, Rebecca; Bouhanna, Dalia; Weintraub, Michael; Stepensky, Polina

2012-07-01

We describe an 11-year-old girl with thalassemia major who underwent a second hematopoietic stem cell transplantation from a matched related donor and who subsequently developed posttransplant lymphoproliferative disorder complicated by severe ascending paralysis resembling Guillian-Barré syndrome. Six months later she developed a massive pericardial effusion. She received a multimodal treatment for these complications and currently, 18 months after transplantation, she is in a good clinical condition, is transfusion independent, with no evidence of graft-versus-host disease and off all treatment. This case highlights the dilemma surrounding second hematopoietic stem cell transplantations in hemoglobinopathies and the need for a careful, well informed, and collaborative decision-making process by patients, families, and medical professionals.

A novel method of mouse ex utero transplantation of hepatic progenitor cells into the fetal liver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shikanai, Mima; Asahina, Kinji; Iseki, Sachiko

2009-04-03

Avoiding the limitations of the adult liver niche, transplantation of hepatic stem/progenitor cells into fetal liver is desirable to analyze immature cells in a hepatic developmental environment. Here, we established a new monitor tool for cell fate of hepatic progenitor cells transplanted into the mouse fetal liver by using ex utero surgery. When embryonic day (ED) 14.5 hepatoblasts were injected into the ED14.5 fetal liver, the transplanted cells expressed albumin abundantly or {alpha}-fetoprotein weakly, and contained glycogen in the neonatal liver, indicating that transplanted hepatoblasts can proliferate and differentiate in concord with surrounding recipient parenchymal cells. The transplanted cells becamemore » mature in the liver of 6-week-old mice. Furthermore, this method was applicable to transplantation of hepatoblast-like cells derived from mouse embryonic stem cells. These data indicate that this unique technique will provide a new in vivo experimental system for studying cell fate of hepatic stem/progenitor cells and liver organogenesis.« less

Specification of regional intestinal stem cell identity during Drosophila metamorphosis.

PubMed

Driver, Ian; Ohlstein, Benjamin

2014-05-01

In the adult Drosophila midgut the bone morphogenetic protein (BMP) signaling pathway is required to specify and maintain the acid-secreting region of the midgut known as the copper cell region (CCR). BMP signaling is also involved in the modulation of intestinal stem cell (ISC) proliferation in response to injury. How ISCs are able to respond to the same signaling pathway in a regionally different manner is currently unknown. Here, we show that dual use of the BMP signaling pathway in the midgut is possible because BMP signals are only capable of transforming ISC and enterocyte identity during a defined window of metamorphosis. ISC heterogeneity is established prior to adulthood and then maintained in cooperation with regional signals from surrounding tissue. Our data provide a conceptual framework for how other tissues maintained by regional stem cells might be patterned and establishes the pupal and adult midgut as a novel genetic platform for identifying genes necessary for regional stem cell specification and maintenance.

Localization of lead accumulated by corn plants. [Zea mays L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malone, C.; Koeppe, D.E.; Miller, R.J.

1974-01-01

Light and electron microscopic studies of corn plants (Zea mays L.) exposed to Pb in hydroponic solution showed that the roots generally accumulated a surface Pb precipitate and slowly accumulated Pb crystals in the cell walls. The root surface precipitate formed without the apparent influence of any cell organelles. In contrast, Pb taken up by roots was concentrated in dicytosome vesicles. Dicytosome vesicles containing cell wall material fused with one another to encase the Pb deposit. This encased deposit which was surrounded by a membrane migrated toward the outside of the cell where the membrane surrounding the deposit then fusedmore » with the plasmalemma. The material surrounding the deposit then fused with the cell wall. The result of this process was a concentration of Pb deposits in the cell wall outside the plasmalemma. Similar deposits were observed in stems and leaves suggesting that Pb was transported and deposited in a similar manner.« less

Localization of Lead Accumulated by Corn Plants 1

PubMed Central

Malone, Carl; Koeppe, D. E.; Miller, Raymond J.

1974-01-01

Light and electron microscopic studies of corn plants (Zea mays L.) exposed to Pb in hydroponic solution showed that the roots generally accumulated a surface Pb precipitate and slowly accumulated Pb crystals in the cell walls. The root surface precipitate formed without the apparent influence of any cell organelles. In contrast, Pb taken up by roots was concentrated in dictyosome vesicles. Dictyosome vesicles containing cell wall material fused with one another to encase the Pb deposit. This encased deposit which was surrounded by a membrane migrated toward the outside of the cell where the membrane surrounding the deposit fused with the plasmalemma. The material surrounding the deposit then fused with the cell wall. The result of this process was a concentration of Pb deposits in the cell wall outside the plasmalemma. Similar deposits were observed in stems and leaves suggesting that Pb was transported and deposited in a similar manner. Images PMID:16658711

Current-Controlled Electrical Point-Source Stimulation of Embryonic Stem Cells

PubMed Central

Chen, Michael Q.; Xie, Xiaoyan; Wilson, Kitchener D.; Sun, Ning; Wu, Joseph C.; Giovangrandi, Laurent; Kovacs, Gregory T. A.

2010-01-01

Stem cell therapy is emerging as a promising clinical approach for myocardial repair. However, the interactions between the graft and host, resulting in inconsistent levels of integration, remain largely unknown. In particular, the influence of electrical activity of the surrounding host tissue on graft differentiation and integration is poorly understood. In order to study this influence under controlled conditions, an in vitro system was developed. Electrical pacing of differentiating murine embryonic stem (ES) cells was performed at physiologically relevant levels through direct contact with microelectrodes, simulating the local activation resulting from contact with surrounding electroactive tissue. Cells stimulated with a charged balanced voltage-controlled current source for up to 4 days were analyzed for cardiac and ES cell gene expression using real-time PCR, immunofluorescent imaging, and genome microarray analysis. Results varied between ES cells from three progressive differentiation stages and stimulation amplitudes (nine conditions), indicating a high sensitivity to electrical pacing. Conditions that maximally encouraged cardiomyocyte differentiation were found with Day 7 EBs stimulated at 30 µA. The resulting gene expression included a sixfold increase in troponin-T and a twofold increase in β-MHCwithout increasing ES cell proliferation marker Nanog. Subsequent genome microarray analysis revealed broad transcriptome changes after pacing. Concurrent to upregulation of mature gene programs including cardiovascular, neurological, and musculoskeletal systems is the apparent downregulation of important self-renewal and pluripotency genes. Overall, a robust system capable of long-term stimulation of ES cells is demonstrated, and specific conditions are outlined that most encourage cardiomyocyte differentiation. PMID:20652088

Unique and Conserved Features of the Barley Root Meristem

PubMed Central

Kirschner, Gwendolyn K.; Stahl, Yvonne; Von Korff, Maria; Simon, Rüdiger

2017-01-01

Plant root growth is enabled by root meristems that harbor the stem cell niches as a source of progenitors for the different root tissues. Understanding the root development of diverse plant species is important to be able to control root growth in order to gain better performances of crop plants. In this study, we analyzed the root meristem of the fourth most abundant crop plant, barley (Hordeum vulgare). Cell division studies revealed that the barley stem cell niche comprises a Quiescent Center (QC) of around 30 cells with low mitotic activity. The surrounding stem cells contribute to root growth through the production of new cells that are displaced from the meristem, elongate and differentiate into specialized root tissues. The distal stem cells produce the root cap and lateral root cap cells, while cells lateral to the QC generate the epidermis, as it is typical for monocots. Endodermis and inner cortex are derived from one common initial lateral to the QC, while the outer cortex cell layers are derived from a distinct stem cell. In rice and Arabidopsis, meristem homeostasis is achieved through feedback signaling from differentiated cells involving peptides of the CLE family. Application of synthetic CLE40 orthologous peptide from barley promotes meristem cell differentiation, similar to rice and Arabidopsis. However, in contrast to Arabidopsis, the columella stem cells do not respond to the CLE40 peptide, indicating that distinct mechanisms control columella cell fate in monocot and dicot plants. PMID:28785269

Isolation and functional assessment of cutaneous stem cells.

PubMed

Doucet, Yanne S; Owens, David M

2015-01-01

The epidermis and associated appendages of the skin represent a multi-lineage tissue that is maintained by perpetual rounds of renewal. During homeostasis, turnover of epidermal lineages is achieved by input from regionalized keratinocytes stem or progenitor populations with little overlap from neighboring niches. Over the last decade, molecular markers selectively expressed by a number of these stem or progenitor pools have been identified, allowing for the isolation and functional assessment of stem cells and genetic lineage tracing analysis within intact skin. These advancements have led to many fundamental observations about epidermal stem cell function such as the identification of their progeny, their role in maintenance of skin homeostasis, or their contribution to wound healing. In this chapter, we provide a methodology to identify and isolate epidermal stem cells and to assess their functional role in their respective niche. Furthermore, recent evidence has shown that the microenvironment also plays a crucial role in stem cell function. Indeed, epidermal cells are under the influence of surrounding fibroblasts, adipocytes, and sensory neurons that provide extrinsic signals and mechanical cues to the niche and contribute to skin morphogenesis and homeostasis. A better understanding of these microenvironmental cues will help engineer in vitro experimental models with more relevance to in vivo skin biology. New approaches to address and study these environmental cues in vitro will also be addressed.

Generation of structures formed by lens and retinal cells differentiating from embryonic stem cells.

PubMed

Hirano, Mariko; Yamamoto, Akitsugu; Yoshimura, Naoko; Tokunaga, Tomoyuki; Motohashi, Tsutomu; Ishizaki, Katsuhiko; Yoshida, Hisahiro; Okazaki, Kenji; Yamazaki, Hidetoshi; Hayashi, Shin-Ichi; Kunisada, Takahiro

2003-12-01

Embryonic stem cells have the potential to give rise to all cell lineages when introduced into the early embryo. They also give rise to a limited number of different cell types in vitro in specialized culture systems. In this study, we established a culture system in which a structure consisting of lens, neural retina, and pigmented retina was efficiently induced from embryonic stem cells. Refractile cell masses containing lens and neural retina were surrounded by retinal pigment epithelium layers and, thus, designated as eye-like structures. Developmental processes required for eye development appear to proceed in this culture system, because the formation of the eye-like structures depended on the expression of Pax6, a key transcription factor for eye development. The present culture system opens up the possibility of examining early stages of eye development and also of producing cells for use in cellular therapy for various diseases of the eye. Copyright 2003 Wiley-Liss, Inc.

Autonomous assembly of epithelial structures by subrenal implantation of dissociated embryonic inner-ear cells.

PubMed

Wang, Li; Zhang, Kaiqing; Zhu, Helen He; Gao, Wei-Qiang

2015-05-27

Microenvironment and cell-cell interactions play an important role during embryogenesis and are required for the stemness and differentiation of stem cells. The inner-ear sensory epithelium, containing hair cells and supporting cells, is derived from the stem cells within the otic vesicle at early embryonic stages. However, whether or not such microenvironment or cell-cell interactions within the embryonic otic tissue have the capacity to regulate the proliferation and differentiation of stem cells and to autonomously reassemble the cells into epithelial structures is unknown. Here, we report that on enzymatic digestion and dissociation to harvest all the single cells from 13.5-day-old rat embryonic (E13.5) inner-ear tissue as well as on implantation of these cells under renal capsules; the dissociated cells are able to reassemble themselves to form epithelial structures as early as 7 days after implantation. By 25 days after implantation, more mature epithelial structures are formed. Immunostaining with cell-type-specific markers reveals that hair cells and supporting cells are not only formed, but are also well aligned with the hair cells located in the apical layer surrounded by the supporting cells. These findings suggest that microenvironment and cell-cell interactions within the embryonic inner-ear tissue have the autonomous signals to induce the formation of sensory epithelial structures. This method may also provide a useful system to study the potential of stem cells to differentiate into hair cells in vivo.

Symplastic isolation of the sieve element-companion cell complex in the phloem of Ricinus communis and Salix alba stems.

PubMed

van Bel, A J; Kempers, R

1991-12-01

The anatomical and physiological isolation of the sieve element-companion cell complex (se-cc complex) was investigated in stems of Ricinus communis L. and Salix alba L. In Ricinus, the plasmodesmatal frequencies were in the proportions 8∶1∶2∶30, in the order given, at the interfaces between sieve tube-companion cell, sieve tube-phloem parenchyma cell, companion cellphloem parenchyma cell, and phloem parenchyma cellphloem parenchyma cell. The membrane potentials of the se-cc complex and the surrounding phloem-parenchyma cells sharply contrasted: the membrane potential of the se-cc complex was about twice as negative as that of the phloem parenchyma. Lucifer Yellow CH injected into the sieve element or into the companion cell remained within the se-cc complex. Dye introduced into phloem parenchyma only moved (mostly poorly) to other phloem-parenchyma cells. The distribution of the plasmodesmatal frequencies, the differential dye-coupling and the sharp discontinuities in membrane potentials indicate that the se-cc complexes constitute symplast domains in the stem phloem. Symplastic autonomy is discussed as a basic necessity for the functioning of the se-cc complex in the stem.

Donor-derived stem-cells and epithelial mesenchymal transition in squamous cell carcinoma in transplant recipients.

PubMed

Verneuil, Laurence; Leboeuf, Christophe; Bousquet, Guilhem; Brugiere, Charlotte; Elbouchtaoui, Morad; Plassa, Louis-François; Peraldi, Marie-Noelle; Lebbé, Celeste; Ratajczak, Philippe; Janin, Anne

2015-12-08

Skin squamous-cell-carcinoma (SCC), is the main complication in long-term kidney-transplant recipients, and it can include donor-derived cells. Preclinical models demonstrated the involvement of epithelial mesenchymal transition (EMT) in the progression of skin SCC, and the role of Snail, an EMT transcription factor, in cancer stem-cell survival and expansion.Here, we studied stem-cells and EMT expression in SCCs and concomitant actinic keratoses (AK) in kidney-transplant recipients. In SCC and AK in 3 female recipients of male kidney-transplants, donor-derived Y chromosome in epidermal stem cells was assessed using combined XY-FISH/CD133 immunostaining, and digital-droplet-PCR on laser-microdissected CD133 expressing epidermal cells.For EMT study, double immunostainings of CD133 with vimentin or snail and slug, electron microscopy and immunostainings of keratinocytes junctions were performed. Digital droplet PCR was used to check CDH1 (E-cadherin) expression level in laser-microdissected cells co-expressing CD133 and vimentin or snail and slug.The numbers of Y-chromosome were assessed using digital droplet PCR in laser-microdissected cells co-expressing CD133 and vimentin, or snail and slug, and in CD133 positive cells not expressing any EMT maker. We identified donor-derived stem-cells in basal layers and invasive areas in all skin SCCs and in concomitant AKs, but not in surrounding normal skin.The donor-derived stem-cells expressed the EMT markers, vimentin, snail and slug in SCCs but not in AKs. The expression of the EMT transcription factor, SNAI1, was higher in stem-cells when they expressed vimentin. They were located in invasive areas of SCCs. In these areas, the expressions of claudin-1 and desmoglein 1 were reduced or absent, and within the basal layer there were features of basal membrane disappearance.Donor-derived stem cells were in larger numbers in stem cells co-expressing vimentin or snail and slug than in stem cells not expressing any EMT marker. We identified here donor-derived stem cells within skin SCC in kidney-transplant recipients. They were located in invasive areas of SCC and had EMT characteristics.

Characterization of human skeletal stem and bone cell populations using dielectrophoresis.

PubMed

Ismail, A; Hughes, M P; Mulhall, H J; Oreffo, R O C; Labeed, F H

2015-02-01

Dielectrophoresis (DEP) is a non-invasive cell analysis method that uses differences in electrical properties between particles and surrounding medium to determine a unique set of cellular properties that can be used as a basis for cell separation. Cell-based therapies using skeletal stem cells are currently one of the most promising areas for treating a variety of skeletal and muscular disorders. However, identifying and sorting these cells remains a challenge in the absence of unique skeletal stem cell markers. DEP provides an ideal method for identifying subsets of cells without the need for markers by using their dielectric properties. This study used a 3D dielectrophoretic well chip device to determine the dielectric characteristics of two osteosarcoma cell lines (MG-63 and SAOS-2) and an immunoselected enriched skeletal stem cell fraction (STRO-1 positive cell) of human bone marrow. Skeletal cells were exposed to a series of different frequencies to induce dielectrophoretic cell movement, and a model was developed to generate the membrane and cytoplasmic properties of the cell populations. Differences were observed in the dielectric properties of MG-63, SAOS-2 and STRO-1 enriched skeletal populations, which could potentially be used to sort cells in mixed populations. This study provide evidence of the ability to characterize different human skeletal stem and mature cell populations, and acts as a proof-of-concept that dielectrophoresis can be exploited to detect, isolate and separate skeletal cell populations from heterogeneous bone marrow cell populations. Copyright © 2012 John Wiley & Sons, Ltd.

Cnn dynamics drive centrosome size asymmetry to ensure daughter centriole retention in Drosophila neuroblasts.

PubMed

Conduit, Paul T; Raff, Jordan W

2010-12-21

Centrosomes comprise a pair of centrioles surrounded by an amorphous network of pericentriolar material (PCM). In certain stem cells, the two centrosomes differ in size, and this appears to be important for asymmetric cell division [1, 2]. In some cases, centrosome asymmetry is linked to centriole age because the older, mother centriole always organizes more PCM than the daughter centriole, thus ensuring that the mother centriole is always retained in the stem cell after cell division [3]. This has raised the possibility that an "immortal" mother centriole may help maintain stem cell fate [4, 5]. It is unclear, however, how centrosome size asymmetry is generated in stem cells. Here we provide compelling evidence that centrosome size asymmetry in Drosophila neuroblasts is generated by the differential regulation of Cnn incorporation into the PCM at mother and daughter centrioles. Shortly after centriole separation, mother and daughter centrioles organize similar amounts of PCM, but Cnn incorporation is then rapidly downregulated at the mother centriole, while it is maintained at the daughter centriole. This ensures that the daughter centriole maintains its PCM and so its position at the apical cortex. Thus, the daughter centriole, rather than an "immortal" mother centriole, is ultimately retained in these stem cells.

Synthetic niches for differentiation of human embryonic stem cells bypassing embryoid body formation.

PubMed

Liu, Yarong; Fox, Victoria; Lei, Yuning; Hu, Biliang; Joo, Kye-Il; Wang, Pin

2014-07-01

The unique self-renewal and pluripotency features of human embryonic stem cells (hESCs) offer the potential for unlimited development of novel cell therapies. Currently, hESCs are cultured and differentiated using methods, such as monolayer culture and embryoid body (EB) formation. As such, achieving efficient differentiation into higher order structures remains a challenge, as well as maintaining cell viability during differentiation into homogeneous cell populations. Here, we describe the application of highly porous polymer scaffolds as synthetic stem cell niches. Bypassing the EB formation step, these scaffolds are capable of three-dimensional culture of undifferentiated hESCs and subsequent directed differentiation into three primary germ layers. H9 hESCs were successfully maintained and proliferated in biodegradable polymer scaffolds based on poly (lactic-co-glycolic acid) (PLGA). The results showed that cells within PLGA scaffolds retained characteristics of undifferentiated pluripotent stem cells. Moreover, the scaffolds allowed differentiation towards the lineage of interest by the addition of growth factors to the culture system. The in vivo transplantation study revealed that the scaffolds could provide a microenvironment that enabled hESCs to interact with their surroundings, thereby promoting cell differentiation. Therefore, this approach, which provides a unique culture/differentiation system for hESCs, will find its utility in various stem cell-based tissue-engineering applications. © 2013 Wiley Periodicals, Inc.

Mesenchymal Cells of the Intestinal Lamina Propria

PubMed Central

Powell, D.W.; Pinchuk, I.V.; Saada, J.I.; Chen, Xin; Mifflin, R.C.

2013-01-01

The mesenchymal elements of the intestinal lamina propria reviewed here are the myofibroblasts, fibroblasts, mural cells (pericytes) of the vasculature, bone marrow–derived stromal stem cells, smooth muscle of the muscularis mucosae, and smooth muscle surrounding the lymphatic lacteals. These cells share similar marker molecules, origins, and coordinated biological functions previously ascribed solely to subepithelial myofibroblasts. We review the functional anatomy of intestinal mesenchymal cells and describe what is known about their origin in the embryo and their replacement in adults. As part of their putative role in intestinal mucosal morphogenesis, we consider the intestinal stem cell niche. Lastly, we review emerging information about myofibroblasts as nonprofessional immune cells that may be important as an alarm system for the gut and as a participant in peripheral immune tolerance. PMID:21054163

Tumor tropism of intravenously injected human-induced pluripotent stem cell-derived neural stem cells and their gene therapy application in a metastatic breast cancer model.

PubMed

Yang, Jing; Lam, Dang Hoang; Goh, Sally Sallee; Lee, Esther Xingwei; Zhao, Ying; Tay, Felix Chang; Chen, Can; Du, Shouhui; Balasundaram, Ghayathri; Shahbazi, Mohammad; Tham, Chee Kian; Ng, Wai Hoe; Toh, Han Chong; Wang, Shu

2012-05-01

Human pluripotent stem cells can serve as an accessible and reliable source for the generation of functional human cells for medical therapies. In this study, we used a conventional lentiviral transduction method to derive human-induced pluripotent stem (iPS) cells from primary human fibroblasts and then generated neural stem cells (NSCs) from the iPS cells. Using a dual-color whole-body imaging technology, we demonstrated that after tail vein injection, these human NSCs displayed a robust migratory capacity outside the central nervous system in both immunodeficient and immunocompetent mice and homed in on established orthotopic 4T1 mouse mammary tumors. To investigate whether the iPS cell-derived NSCs can be used as a cellular delivery vehicle for cancer gene therapy, the cells were transduced with a baculoviral vector containing the herpes simplex virus thymidine kinase suicide gene and injected through tail vein into 4T1 tumor-bearing mice. The transduced NSCs were effective in inhibiting the growth of the orthotopic 4T1 breast tumor and the metastatic spread of the cancer cells in the presence of ganciclovir, leading to prolonged survival of the tumor-bearing mice. The use of iPS cell-derived NSCs for cancer gene therapy bypasses the sensitive ethical issue surrounding the use of cells derived from human fetal tissues or human embryonic stem cells. This approach may also help to overcome problems associated with allogeneic transplantation of other types of human NSCs. Copyright © 2012 AlphaMed Press.

Biodegradable composite scaffolds: a strategy to modulate stem cell behaviour.

PubMed

Armentano, Ilaria; Fortunati, Elena; Mattioli, Samantha; Rescignano, Nicolatta; Kenny, José M

2013-04-01

The application of new biomaterial technologies offers the potential to direct the stem cell fate, targeting the delivery of cells and reducing immune rejection, thereby supporting the development of regenerative medicine. Cells respond to their surrounding structure and with nanostructures exhibit unique proliferative and differentiation properties. This review presents the relevance, the promising perspectives and challenges of current biodegradable composite scaffolds in terms of material properties, processing technology and surface modification, focusing on significant recent patents in these fields. It has been reported how biodegradable porous composite scaffolds can be engineered with initial properties that reproduce the anisotropy, viscoelasticity, tension-compression non-linearity of different tissues by introducing specific nanostructures. Moreover the modulation of electrical, morphological, surface and topographic scaffold properties enables specific stem cell response. Recent advances in nanotechnology have allowed to engineer novel biomaterials with these complexity levels. Understanding the specific biological response triggered by various aspects of the fibrous environment is important in guiding the design and engineering of novel substrates that mimic the native cell matrix interactions in vivo.

Distinct spatial distribution of microglia and macrophages following mesenchymal stem cell implantation in mouse brain.

PubMed

Le Blon, Debbie; Hoornaert, Chloé; Daans, Jasmijn; Santermans, Eva; Hens, Niel; Goossens, Herman; Berneman, Zwi; Ponsaerts, Peter

2014-09-01

Although implantation of cellular material in the central nervous system (CNS) is a key direction in CNS regenerative medicine, this approach is currently limited by the occurrence of strong endogenous immune cell responses. In a model of mesenchymal stem cell (MSC) grafting in the CNS of immune-competent mice, we previously described that MSC grafts become highly surrounded and invaded by Iba1(+) myeloid cells (microglia and/or macrophages). Here, following grafting of blue fluorescent protein (BFP)-expressing MSC in the CNS of CX3CR1(+/-) and CX3CR1(-/-) mice, our results indicate: (1) that the observed inflammatory response is independent of the fractalkine signalling axis, and (2) that a significant spatial distribution of Iba1(+) inflammatory cells occurs, in which Iba1(+) CX3CR1(+) myeloid cells mainly surround the MSC graft and Iba1(+) CX3CR1(-) myeloid cells mainly invade the graft at 10 days post transplantation. Although Iba1(+) CX3CR1(+) myeloid cells are considered to be of resident microglial origin, Iba1(+) CX3CR1(-) myeloid cells are most likely of peripheral monocyte/macrophage origin. In order to confirm the latter, we performed MSC-BFP grafting experiments in the CNS of eGFP(+) bone marrow chimeric C57BL/6 mice. Analysis of MSC-BFP grafts in the CNS of these mice confirmed our observation that peripheral monocytes/macrophages invade the MSC graft and that resident microglia surround the MSC graft site. Furthermore, analysis of major histocompatibility complex class II (MHCII) expression revealed that mainly macrophages, but not microglia, express this M1 pro-inflammatory marker in the context of MSC grafting in the CNS. These results again highlight the complexity of cell implantation immunology in the CNS.

Human stem cells for craniomaxillofacial reconstruction.

PubMed

Jalali, Morteza; Kirkpatrick, William Niall Alexander; Cameron, Malcolm Gregor; Pauklin, Siim; Vallier, Ludovic

2014-07-01

Human stem cell research represents an exceptional opportunity for regenerative medicine and the surgical reconstruction of the craniomaxillofacial complex. The correct architecture and function of the vastly diverse tissues of this important anatomical region are critical for life supportive processes, the delivery of senses, social interaction, and aesthetics. Craniomaxillofacial tissue loss is commonly associated with inflammatory responses of the surrounding tissue, significant scarring, disfigurement, and psychological sequelae as an inevitable consequence. The in vitro production of fully functional cells for skin, muscle, cartilage, bone, and neurovascular tissue formation from human stem cells, may one day provide novel materials for the reconstructive surgeon operating on patients with both hard and soft tissue deficit due to cancer, congenital disease, or trauma. However, the clinical translation of human stem cell technology, including the application of human pluripotent stem cells (hPSCs) in novel regenerative therapies, faces several hurdles that must be solved to permit safe and effective use in patients. The basic biology of hPSCs remains to be fully elucidated and concerns of tumorigenicity need to be addressed, prior to the development of cell transplantation treatments. Furthermore, functional comparison of in vitro generated tissue to their in vivo counterparts will be necessary for confirmation of maturity and suitability for application in reconstructive surgery. Here, we provide an overview of human stem cells in disease modeling, drug screening, and therapeutics, while also discussing the application of regenerative medicine for craniomaxillofacial tissue deficit and surgical reconstruction.

Human Stem Cells for Craniomaxillofacial Reconstruction

PubMed Central

Kirkpatrick, William Niall Alexander; Cameron, Malcolm Gregor

2014-01-01

Human stem cell research represents an exceptional opportunity for regenerative medicine and the surgical reconstruction of the craniomaxillofacial complex. The correct architecture and function of the vastly diverse tissues of this important anatomical region are critical for life supportive processes, the delivery of senses, social interaction, and aesthetics. Craniomaxillofacial tissue loss is commonly associated with inflammatory responses of the surrounding tissue, significant scarring, disfigurement, and psychological sequelae as an inevitable consequence. The in vitro production of fully functional cells for skin, muscle, cartilage, bone, and neurovascular tissue formation from human stem cells, may one day provide novel materials for the reconstructive surgeon operating on patients with both hard and soft tissue deficit due to cancer, congenital disease, or trauma. However, the clinical translation of human stem cell technology, including the application of human pluripotent stem cells (hPSCs) in novel regenerative therapies, faces several hurdles that must be solved to permit safe and effective use in patients. The basic biology of hPSCs remains to be fully elucidated and concerns of tumorigenicity need to be addressed, prior to the development of cell transplantation treatments. Furthermore, functional comparison of in vitro generated tissue to their in vivo counterparts will be necessary for confirmation of maturity and suitability for application in reconstructive surgery. Here, we provide an overview of human stem cells in disease modeling, drug screening, and therapeutics, while also discussing the application of regenerative medicine for craniomaxillofacial tissue deficit and surgical reconstruction. PMID:24564584

Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation.

PubMed

Handschel, Jörg; Naujoks, Christian; Depprich, Rita; Lammers, Lydia; Kübler, Norbert; Meyer, Ulrich; Wiesmann, Hans-Peter

2011-07-14

Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs) in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG). After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin. © 2011 Handschel et al; licensee BioMed Central Ltd.

Gingival Mesenchymal Stem/Progenitor Cells: A Unique Tissue Engineering Gem

PubMed Central

Fawzy El-Sayed, Karim M.; Dörfer, Christof E.

2016-01-01

The human gingiva, characterized by its outstanding scarless wound healing properties, is a unique tissue and a pivotal component of the periodontal apparatus, investing and surrounding the teeth in their sockets in the alveolar bone. In the last years gingival mesenchymal stem/progenitor cells (G-MSCs), with promising regenerative and immunomodulatory properties, have been isolated and characterized from the gingival lamina propria. These cells, in contrast to other mesenchymal stem/progenitor cell sources, are abundant, readily accessible, and easily obtainable via minimally invasive cell isolation techniques. The present review summarizes the current scientific evidence on G-MSCs' isolation, their characterization, the investigated subpopulations, the generated induced pluripotent stem cells- (iPSC-) like G-MSCs, their regenerative properties, and current approaches for G-MSCs' delivery. The review further demonstrates their immunomodulatory properties, the transplantation preconditioning attempts via multiple biomolecules to enhance their attributes, and the experimental therapeutic applications conducted to treat multiple diseases in experimental animal models in vivo. G-MSCs show remarkable tissue reparative/regenerative potential, noteworthy immunomodulatory properties, and primary experimental therapeutic applications of G-MSCs are very promising, pointing at future biologically based therapeutic techniques, being potentially superior to conventional clinical treatment modalities. PMID:27313628

Actin dynamics involved in gravity perception in Arabidopsis inflorescense stem

NASA Astrophysics Data System (ADS)

Tasaka, Masao; Nakamura, Moritaka; Morita, Miyo T.

The amyloplasts sedimentation in the endodermal cells is important for gravity perception in Arabidopsis shoot. Our previous study suggests that SGR5(SHOOT GRAVITROPISM 5) and SGR9 are synergistically involved in regulation of amyloplast movement in these cells, and shows that sgr5 sgr9 double mutant completely loses gravitropic response. SGR5 encodes putative transcription factor and SGR9 encodes a ring finger containing protein, which surrounds amyloplasts. It has been reported that amyloplasts are surrounded by actin microfilaments (MFs), and that treatment with actin polymerization inhibitor enhances gravitropic organ curvature. However, not only the molecular link between amyolplasts and MFs, but also regulatory role of MFs in gravitropic response is still unclear. Here, we found that treatment with actin polymerization inhibitor restored gravitropic response of sgr5 sgr9 double mutant stems. The result suggests that abnormal amyloplasts movement in the double mutant could result from inhibition of MFs depolymerization, leading to abnormal gravitropism. We are investigating whether SGR5 and SGR9 are involved in amyloplasts movement by regulating actin remodeling in gravity perceptive cells.

Extracellular Vesicles in Physiology, Pathology, and Therapy of the Immune and Central Nervous System, with Focus on Extracellular Vesicles Derived from Mesenchymal Stem Cells as Therapeutic Tools

PubMed Central

Koniusz, Sylwia; Andrzejewska, Anna; Muraca, Maurizio; Srivastava, Amit K.; Janowski, Miroslaw; Lukomska, Barbara

2016-01-01

Extracellular vesicles (EVs) are membrane-surrounded structures released by most cell types. They are characterized by a specific set of proteins, lipids and nucleic acids. EVs have been recognized as potent vehicles of intercellular communication to transmit biological signals between cells. In addition, pathophysiological roles of EVs in conditions like cancer, infectious diseases and neurodegenerative disorders are well established. In recent years focus has been shifted on therapeutic use of stem cell derived-EVs. Use of stem cell derived-EVs present distinct advantage over the whole stem cells as EVs do not replicate and after intravenous administration, they are less likely to trap inside the lungs. From the therapeutic perspective, the most promising cellular sources of EVs are mesenchymal stem cells (MSCs), which are easy to obtain and maintain. Therapeutic activity of MSCs has been shown in numerous animal models and the beneficial paracrine effect of MSCs may be mediated by EVs. The various components of MSC derived-EVs such as proteins, lipids, and RNA might play a specific therapeutic role. In this review, we characterize the role of EVs in immune and central nervous system (CNS); present evidences for defective signaling of these vesicles in neurodegeneration and therapeutic role of EVs in CNS. PMID:27199663

Mesenchymal-epithelial interactions during hair follicle morphogenesis and cycling

PubMed Central

Sennett, Rachel; Rendl, Michael

2012-01-01

Embryonic hair follicle induction and formation are regulated by mesenchymal-epithelial interactions between specialized dermal cells and epidermal stem cells that switch to a hair fate. Similarly, during postnatal hair growth, communication between mesenchymal dermal papilla cells and surrounding epithelial matrix cells coordinates hair shaft production. Adult hair follicle regeneration in the hair cycle again is thought to be controlled by activating signals originating from the mesenchymal compartment and acting on hair follicle stem cells. Although many signaling pathways are implicated in hair follicle formation and growth, the precise nature, timing, and intersection of these inductive and regulatory signals remains elusive. The goal of this review is to summarize our current understanding and to discuss recent new insights into mesenchymal-epithelial interactions during hair follicle morphogenesis and cycling. PMID:22960356

In vitro bioactivity of Bioroot™ RCS, via A4 mouse pulpal stem cells.

PubMed

Dimitrova-Nakov, Sasha; Uzunoglu, Emel; Ardila-Osorio, Hector; Baudry, Anne; Richard, Gilles; Kellermann, Odile; Goldberg, Michel

2015-11-01

To evaluate the biocompatibility and osteoinductive properties of Bioroot™ RCS (BR, Septodont, France) compared to Kerr's Pulp Canal Sealer™ (PCS, Kerr, Italy) using the mouse pulp-derived stem cell line A4, which have an osteo/odontogenic potential in vitro and contribute to efficient bone repair in vivo. A4 cells were cultured at the stem cell stage in the presence of solid disks of BR or PCS, whereas untreated A4 cells were used as control. After 3, 7, 10 days of direct contact with the sealers, cell viability was quantified using Trypan Blue exclusion assay. Immunolabelings were performed to assess the expression of odontoblast markers i.e. type 1 collagen, DMP1 or BSP. Finally, sealer-treated cells were induced toward osteo/odontogenic differentiation to assess the impact of the sealers on mineralization by Von Kossa staining. Statistical significance was evaluated by one-way analysis of variance and t-test (p<0.05). BR did not alter the viability and morphology of A4 pulpal cells compared to control group (p>0.05); however, living cell percentage of PCS was significantly lower compared to control and BR groups (p<0.05). BR preserved the intrinsic ability of A4 cells to express type 1 collagen, DMP1 or BSP at the stem cell stage. It did not alter the integrity of collagen fibers surrounding the cells and promoted overexpression of BSP and DMP1 at the cell surface. In contrast to PCS, BR did not compromise the mineralization potential of pulpal A4 stem cells. Bioroot™ RCS was not as cytotoxic as PCS. It did not recruit the pulpal stem cells toward differentiation but preserve their osteo-odontogenic intrinsic properties. Bioroot™ RCS might provide more suitable environment to induce stem cells for hard tissue deposition. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Tumourigenicity and radiation resistance of mesenchymal stem cells.

PubMed

D'Andrea, Filippo P; Horsman, Michael R; Kassem, Moustapha; Overgaard, Jens; Safwat, Akmal

2012-05-01

Cancer stem cells are believed to be more radiation resistant than differentiated tumour cells of the same origin. It is not known, however, whether normal nontransformed adult stem cells share the same radioresistance as their cancerous counterpart. Nontumourigenic (TERT4) and tumourigenic (TRET20) cell lines, from an immortalised mesenchymal stem cell line, were grown in culture prior to irradiation and gene expression analysis. Radiation resistance was measured using a clonogenic assay. Differences in gene expression between the two cell lines, both under nontreated and irradiated conditions, were assessed with microarrays (Affymetrix Human Exon 1.0 ST array). The cellular functions affected by the altered gene expressions were assessed through gene pathway mapping (Ingenuity Pathway Analysis). Based on the clonogenic assay the nontumourigenic cell line was found to be more sensitive to radiation than the tumourigenic cell line. Using the exon chips, 297 genes were found altered between untreated samples of the cell lines whereas only 16 genes responded to radiation treatment. Among the genes with altered expression between the untreated samples were PLAU, PLAUR, TIMP3, MMP1 and LOX. The pathway analysis based on the alteration between the untreated samples indicated cancer and connective tissue disorders. This study has shown possible common genetic events linking tumourigenicity and radiation response. The PLAU and PLAUR genes are involved in apoptosis evasion while the genes TIMP3, MMP1 and LOX are involved in regulation of the surrounding matrix. The first group may contribute to the difference in radiation resistance observed and the latter could be a major contributor to the tumourigenic capabilities by degrading the intercellular matrix. These results also indicate that cancer stem cells are more radiation resistant than stem cells of the same origin.

Low oxygen tension enhances endothelial fate of human pluripotent stem cells.

PubMed

Kusuma, Sravanti; Peijnenburg, Elizabeth; Patel, Parth; Gerecht, Sharon

2014-04-01

A critical regulator of the developing or regenerating vasculature is low oxygen tension. Precise elucidation of the role of low oxygen environments on endothelial commitment from human pluripotent stem cells necessitates controlled in vitro differentiation environments. We used a feeder-free, 2-dimensional differentiation system in which we could monitor accurately dissolved oxygen levels during human pluripotent stem cell differentiation toward early vascular cells (EVCs). We found that oxygen uptake rate of differentiating human pluripotent stem cells is lower in 5% O2 compared with atmospheric conditions. EVCs differentiated in 5% O2 had an increased vascular endothelial cadherin expression with clusters of vascular endothelial cadherin+ cells surrounded by platelet-derived growth factor β+ cells. When we assessed the temporal effects of low oxygen differentiation environments, we determined that low oxygen environments during the early stages of EVC differentiation enhance endothelial lineage commitment. EVCs differentiated in 5% O2 exhibited an increased expression of vascular endothelial cadherin and CD31 along with their localization to the membrane, enhanced lectin binding and acetylated low-density lipoprotein uptake, rapid cord-like structure formation, and increased expression of arterial endothelial cell markers. Inhibition of reactive oxygen species generation during the early stages of differentiation abrogated the endothelial inductive effects of the low oxygen environments. Low oxygen tension during early stages of EVC derivation induces endothelial commitment and maturation through the accumulation of reactive oxygen species, highlighting the importance of regulating oxygen tensions during human pluripotent stem cell-vascular differentiation.

The evolution of policy issues in stem cell research: an international survey.

PubMed

Caulfield, Timothy; Rachul, Christen; Zarzeczny, Amy

2012-12-01

Stem cell research remains a tremendously promising yet controversial field of study. It continues to attract considerable public interest and generate discussion and debate. However, while the high profile of this field has endured, the tone and nature of the discourse that drives this profile appears to be changing. In order to get a better sense of how these potential shifts are perceived by individuals directly embedded in the field, we conducted an international internet survey of members of the stem cell research community. Our participants included individuals publishing on both scientific and ethical, legal and social issues topics. We explored the degree to which participants perceived that key policy issues were becoming more or less contentious over time. We queried views regarding the effect of regulatory frameworks on emerging stem cell research technologies and the extent to which participants experience pressure related to clinical translation. We also explored participants' relationships with industry, experience with patents and perceptions regarding the emphasis placed on the potential economic benefits of stem cell research. Our results suggest that while traditional debates such as those surrounding the moral status of the embryo remain, other issues more closely associated with clinical translation and commercialization are perceived as becoming increasingly contentious. This survey provides useful insight into the perspectives of a sample of active researchers working in countries around the world as well as an opportunity to reflect on the likely direction of future stem cell policy debates.

Using therapeutic cloning to fight human disease: a conundrum or reality?

PubMed

Hall, Vanessa J; Stojkovic, Petra; Stojkovic, Miodrag

2006-07-01

The development and transplantation of autologous cells derived from nuclear transfer embryonic stem cell (NT-ESC) lines to treat patients suffering from disease has been termed therapeutic cloning. Human NT is still a developing field, with further research required to improve somatic cell NT and human embryonic stem cell differentiation to deliver safe and effective cell replacement therapies. Furthermore, the implications of transferring mitochondrial heteroplasmic cells, which may harbor aberrant epigenetic gene expression profiles, are of concern. The production of human NT-ESC lines also remains plagued by ethical dilemmas, societal concerns, and controversies. Recently, a number of alternate therapeutic strategies have been proposed to circumvent the moral implications surrounding human nuclear transfer. It will be critical to overcome these biological, legislative, and moral restraints to maximize the potential of this therapeutic strategy and to alleviate human disease.

Rhetoric, power and legitimacy: a critical analysis of the public policy disputes surrounding stem cell research in Australia (2005-6).

PubMed

Lysaght, Tamra; Kerridge, Ian

2012-02-01

In December 2006, the Australian Parliament liberalized regulation governing stem cell research. This decision and preceding legislative review generated considerable public debate, which centred on objections to the deliberate creation and destruction of human embryos for research purposes. This paper draws on qualitative research conducted on the public debate surrounding this policy episode. The aim of this research was to examine how science and scientific knowledge are mobilized by participants in these debates to support their arguments. Data were collected from 109 newspaper opinion editorials as well as 23 in-depth interviews and examined using qualitative content and thematic analysis. Results of this analysis depict science as a rhetorical, moral and political resource that provides opportunities for participants to gain legitimacy, negotiate meaning and assert authority in the public domain. The mobilization of science in public discourse is discussed along with suggestions that are aimed at encouraging greater transparency and inclusiveness in public debates around contested science and emergent technologies.

Testicular cell conditioned medium supports differentiation of embryonic stem cells into ovarian structures containing oocytes.

PubMed

Lacham-Kaplan, Orly; Chy, Hun; Trounson, Alan

2006-02-01

Previous reports and the current study have found that germ cell precursor cells appear in embryoid bodies (EBs) formed from mouse embryonic stem cells as identified by positive expression of specific germ cell markers such as Oct-3/4, Mvh, c-kit, Stella, and DAZL. We hypothesized that if exposed to appropriate growth factors, the germ cell precursor cells within the EBs would differentiate into gametes. The source for growth factors used in the present study is conditioned medium collected from testicular cell cultures prepared from the testes of newborn males. Testes at this stage of development contain most growth factors required for the transformation of germ stem cells into differentiated gametes. When EBs were cultured in the conditioned medium, they developed into ovarian structures, which contained putative oocytes. The oocytes were surrounded by one to two layers of flattened cells and did not have a visible zona pellucida. However, oocyte-specific markers such as Fig-alpha and ZP3 were found expressed by the ovarian structures. The production of oocytes using this method is repeatable and reliable and may be applicable to other mammalian species, including the human.

Through the eyes of young sibling donors: the hematopoietic stem cell donation experience.

PubMed

D'Auria, Jennifer P; Fitzgerald, Tania M; Presler, Cammie M; Kasow, Kimberly A

2015-01-01

This qualitative study used a grounded theory approach to explore how pediatric sibling donors of a successful hematopoietic stem cell transplantation conceptualized their donation experiences. Saving my sister's (or brother's) life describes the central phenomenon identified by this purposive sample of 8 sibling donors. Five themes captured their memories: being the perfect match, stepping up, worrying about the outcome, the waiting process, and sharing a special bond. Further research surrounding changes in relational issues will provide insight into inter-sibling support and the developmental course of the sibling relationship into adulthood when intensified by a health crisis. Copyright © 2015 Elsevier Inc. All rights reserved.

Paracrine Engineering of Human Cardiac Stem Cells With Insulin-Like Growth Factor 1 Enhances Myocardial Repair.

PubMed

Jackson, Robyn; Tilokee, Everad L; Latham, Nicholas; Mount, Seth; Rafatian, Ghazaleh; Strydhorst, Jared; Ye, Bin; Boodhwani, Munir; Chan, Vincent; Ruel, Marc; Ruddy, Terrence D; Suuronen, Erik J; Stewart, Duncan J; Davis, Darryl R

2015-09-11

Insulin-like growth factor 1 (IGF-1) activates prosurvival pathways and improves postischemic cardiac function, but this key cytokine is not robustly expressed by cultured human cardiac stem cells. We explored the influence of an enhanced IGF-1 paracrine signature on explant-derived cardiac stem cell-mediated cardiac repair. Receptor profiling demonstrated that IGF-1 receptor expression was increased in the infarct border zones of experimentally infarcted mice by 1 week after myocardial infarction. Human explant-derived cells underwent somatic gene transfer to overexpress human IGF-1 or the green fluorescent protein reporter alone. After culture in hypoxic reduced-serum media, overexpression of IGF-1 enhanced proliferation and expression of prosurvival transcripts and prosurvival proteins and decreased expression of apoptotic markers in both explant-derived cells and cocultured neonatal rat ventricular cardiomyocytes. Transplant of explant-derived cells genetically engineered to overexpress IGF-1 into immunodeficient mice 1 week after infarction boosted IGF-1 content within infarcted tissue and long-term engraftment of transplanted cells while reducing apoptosis and long-term myocardial scarring. Paracrine engineering of explant-derived cells to overexpress IGF-1 provided a targeted means of improving cardiac stem cell-mediated repair by enhancing the long-term survival of transplanted cells and surrounding myocardium. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Control of germline stem cell self-renewal and differentiation in the Drosophila ovary: concerted actions of niche signals and intrinsic factors.

PubMed

Xie, Ting

2013-01-01

In the Drosophila ovary, germline stem cells (GSCs) physically interact with their niche composed of terminal filament cells, cap cells, and possibly GSC-contacting escort cells (ECs). A GSC divides to generate a self-renewing stem cell that remains in the niche and a differentiating daughter that moves away from the niche. The GSC niche provides a bone morphogenetic protein (BMP) signal that maintains GSC self-renewal by preventing stem cell differentiation via repression of the differentiation-promoting gene bag of marbles (bam). In addition, it expresses E-cadherin, which mediates cell adhesion for anchoring GSCs in the niche, enabling continuous self-renewal. GSCs themselves also express different classes of intrinsic factors, including signal transducers, transcription factors, chromatin remodeling factors, translation regulators, and miRNAs, which control self-renewal by strengthening interactions with the niche and repressing various differentiation pathways. Differentiated GSC daughters, known as cystoblasts (CBs), also express distinct classes of intrinsic factors to inhibit self-renewal and promote germ cell differentiation. Surprisingly, GSC progeny are also dependent on their surrounding ECs for proper differentiation at least partly by preventing BMP from diffusing to the differentiated germ cell zone and by repressing ectopic BMP expression. Therefore, both GSC self-renewal and CB differentiation are controlled by collaborative actions of extrinsic signals and intrinsic factors. Copyright © 2012 Wiley Periodicals, Inc.

How deep cells feel: Mean-field Computations and Experiments

NASA Astrophysics Data System (ADS)

Buxboim, Amnon; Sen, Shamik; Discher, Dennis E.

2009-03-01

Most cells in solid tissues exert contractile forces that mechanically couple them to elastic surroundings and that significantly influence cell adhesion, cytoskeletal organization and differentiation. However, strains within the depths of matrices are often unclear and are likely relevant to thin matrices, such as basement membranes, relative to cell size as well as to defining how far cells can ``feel.'' We present experimental results for cell spreading on thin, ligand- coated gels and for prestress in stem cells in relation to gel stiffness. Matrix thickness affects cell spread area, focal adhesions and cytoskeleton organization in stem cells, which we will compare to differentiated cells. We introduce a finite element computation to estimate the elastostatic deformations within the matrix on which a cell is placed. Interfacial strains between cell and matrix show large deviations only when soft matrices are a fraction of cell dimensions, proving consistent with experiments. 3-D cell morphologies that model stem cell-derived neurons, myoblasts, and osteoblasts show that a cylinder-shaped myoblast induces the highest strains, consistent with the prominent contractility of muscle. Groups of such cells show a weak crosstalk via matrix strains only when cells are much closer than a cell-width. Cells thus feel on length scales closer to that of adhesions than on cellular scales.

Intrinsic protective mechanisms of the neuron-glia network against glioma invasion.

PubMed

Iwadate, Yasuo; Fukuda, Kazumasa; Matsutani, Tomoo; Saeki, Naokatsu

2016-04-01

Gliomas arising in the brain parenchyma infiltrate into the surrounding brain and break down established complex neuron-glia networks. However, mounting evidence suggests that initially the network microenvironment of the adult central nervous system (CNS) is innately non-permissive to glioma cell invasion. The main players are inhibitory molecules in CNS myelin, as well as proteoglycans associated with astrocytes. Neural stem cells, and neurons themselves, possess inhibitory functions against neighboring tumor cells. These mechanisms have evolved to protect the established neuron-glia network, which is necessary for brain function. Greater insight into the interaction between glioma cells and the surrounding neuron-glia network is crucial for developing new therapies for treating these devastating tumors while preserving the important and complex neural functions of patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

A GRFa2/Prop1/stem (GPS) cell niche in the pituitary.

PubMed

Garcia-Lavandeira, Montse; Quereda, Víctor; Flores, Ignacio; Saez, Carmen; Diaz-Rodriguez, Esther; Japon, Miguel A; Ryan, Aymee K; Blasco, Maria A; Dieguez, Carlos; Malumbres, Marcos; Alvarez, Clara V

2009-01-01

The adult endocrine pituitary is known to host several hormone-producing cells regulating major physiological processes during life. Some candidates to progenitor/stem cells have been proposed. However, not much is known about pituitary cell renewal throughout life and its homeostatic regulation during specific physiological changes, such as puberty or pregnancy, or in pathological conditions such as tumor development. We have identified in rodents and humans a niche of non-endocrine cells characterized by the expression of GFRa2, a Ret co-receptor for Neurturin. These cells also express b-Catenin and E-cadherin in an oriented manner suggesting a planar polarity organization for the niche. In addition, cells in the niche uniquely express the pituitary-specific transcription factor Prop1, as well as known progenitor/stem markers such as Sox2, Sox9 and Oct4. Half of these GPS (GFRa2/Prop1/Stem) cells express S-100 whereas surrounding elongated cells in contact with GPS cells express Vimentin. GFRa2+-cells form non-endocrine spheroids in culture. These spheroids can be differentiated to hormone-producing cells or neurons outlining the neuroectoderm potential of these progenitors. In vivo, GPSs cells display slow proliferation after birth, retain BrdU label and show long telomeres in its nuclei, indicating progenitor/stem cell properties in vivo. Our results suggest the presence in the adult pituitary of a specific niche of cells characterized by the expression of GFRa2, the pituitary-specific protein Prop1 and stem cell markers. These GPS cells are able to produce different hormone-producing and neuron-like cells and they may therefore contribute to postnatal pituitary homeostasis. Indeed, the relative abundance of GPS numbers is altered in Cdk4-deficient mice, a model of hypopituitarism induced by the lack of this cyclin-dependent kinase. Thus, GPS cells may display functional relevance in the physiological expansion of the pituitary gland throughout life as well as protection from pituitary disease.

A GRFa2/Prop1/Stem (GPS) Cell Niche in the Pituitary

PubMed Central

Garcia-Lavandeira, Montse; Quereda, Víctor; Flores, Ignacio; Saez, Carmen; Diaz-Rodriguez, Esther; Japon, Miguel A.; Ryan, Aymee K.; Blasco, Maria A.; Dieguez, Carlos; Malumbres, Marcos; Alvarez, Clara V.

2009-01-01

Background The adult endocrine pituitary is known to host several hormone-producing cells regulating major physiological processes during life. Some candidates to progenitor/stem cells have been proposed. However, not much is known about pituitary cell renewal throughout life and its homeostatic regulation during specific physiological changes, such as puberty or pregnancy, or in pathological conditions such as tumor development. Principal Findings We have identified in rodents and humans a niche of non-endocrine cells characterized by the expression of GFRa2, a Ret co-receptor for Neurturin. These cells also express b-Catenin and E-cadherin in an oriented manner suggesting a planar polarity organization for the niche. In addition, cells in the niche uniquely express the pituitary-specific transcription factor Prop1, as well as known progenitor/stem markers such as Sox2, Sox9 and Oct4. Half of these GPS (GFRa2/Prop1/Stem) cells express S-100 whereas surrounding elongated cells in contact with GPS cells express Vimentin. GFRa2+-cells form non-endocrine spheroids in culture. These spheroids can be differentiated to hormone-producing cells or neurons outlining the neuroectoderm potential of these progenitors. In vivo, GPSs cells display slow proliferation after birth, retain BrdU label and show long telomeres in its nuclei, indicating progenitor/stem cell properties in vivo. Significance Our results suggest the presence in the adult pituitary of a specific niche of cells characterized by the expression of GFRa2, the pituitary-specific protein Prop1 and stem cell markers. These GPS cells are able to produce different hormone-producing and neuron-like cells and they may therefore contribute to postnatal pituitary homeostasis. Indeed, the relative abundance of GPS numbers is altered in Cdk4-deficient mice, a model of hypopituitarism induced by the lack of this cyclin-dependent kinase. Thus, GPS cells may display functional relevance in the physiological expansion of the pituitary gland throughout life as well as protection from pituitary disease. PMID:19283075

In Situ Spatiotemporal Mapping of Flow Fields around Seeded Stem Cells at the Subcellular Length Scale

PubMed Central

Song, Min Jae; Dean, David; Knothe Tate, Melissa L.

2010-01-01

A major hurdle to understanding and exploiting interactions between the stem cell and its environment is the lack of a tool for precise delivery of mechanical cues concomitant to observing sub-cellular adaptation of structure. These studies demonstrate the use of microscale particle image velocimetry (μ-PIV) for in situ spatiotemporal mapping of flow fields around mesenchymal stem cells, i.e. murine embryonic multipotent cell line C3H10T1/2, at the subcellular length scale, providing a tool for real time observation and analysis of stem cell adaptation to the prevailing mechanical milieu. In the absence of cells, computational fluid dynamics (CFD) predicts flow regimes within 12% of μ-PIV measures, achieving the technical specifications of the chamber and the flow rates necessary to deliver target shear stresses at a particular height from the base of the flow chamber. However, our μ-PIV studies show that the presence of cells per se as well as the density at which cells are seeded significantly influences local flow fields. Furthermore, for any given cell or cell seeding density, flow regimes vary significantly along the vertical profile of the cell. Hence, the mechanical milieu of the stem cell exposed to shape changing shear stresses, induced by fluid drag, varies with respect to proximity of surrounding cells as well as with respect to apical height. The current study addresses a previously unmet need to predict and observe both flow regimes as well as mechanoadaptation of cells in flow chambers designed to deliver precisely controlled mechanical signals to live cells. An understanding of interactions and adaptation in response to forces at the interface between the surface of the cell and its immediate local environment may be key for de novo engineering of functional tissues from stem cell templates as well as for unraveling the mechanisms underlying multiscale development, growth and adaptation of organisms. PMID:20862249

A Protocol for Decellularizing Mouse Cochleae for Inner Ear Tissue Engineering.

PubMed

Neal, Christopher A; Nelson-Brantley, Jennifer G; Detamore, Michael S; Staecker, Hinrich; Mellott, Adam J

2018-01-01

In mammals, mechanosensory hair cells that facilitate hearing lack the ability to regenerate, which has limited treatments for hearing loss. Current regenerative medicine strategies have focused on transplanting stem cells or genetic manipulation of surrounding support cells in the inner ear to encourage replacement of damaged stem cells to correct hearing loss. Yet, the extracellular matrix (ECM) may play a vital role in inducing and maintaining function of hair cells, and has not been well investigated. Using the cochlear ECM as a scaffold to grow adult stem cells may provide unique insights into how the composition and architecture of the extracellular environment aids cells in sustaining hearing function. Here we present a method for isolating and decellularizing cochleae from mice to use as scaffolds accepting perfused adult stem cells. In the current protocol, cochleae are isolated from euthanized mice, decellularized, and decalcified. Afterward, human Wharton's jelly cells (hWJCs) that were isolated from the umbilical cord were carefully perfused into each cochlea. The cochleae were used as bioreactors, and cells were cultured for 30 days before undergoing processing for analysis. Decellularized cochleae retained identifiable extracellular structures, but did not reveal the presence of cells or noticeable fragments of DNA. Cells perfused into the cochlea invaded most of the interior and exterior of the cochlea and grew without incident over a duration of 30 days. Thus, the current method can be used to study how cochlear ECM affects cell development and behavior.

Resistance in mango against infection by Ceratocystis fimbriata.

PubMed

Araujo, Leonardo; Bispo, Wilka Messner Silva; Cacique, Isaías Severino; Moreira, Wiler Ribas; Rodrigues, Fabrício Ávila

2014-08-01

This study was designed to characterize and describe host cell responses of stem tissue to mango wilt disease caused by the fungus Ceratocystis fimbriata in Brazil. Disease progress was followed, through time, in inoculated stems for two cultivars, 'Ubá' (field resistant) and 'Haden' (field susceptible). Stem sections from inoculated areas were examined using fluorescence light microscopy and transmission and scanning electron microscopy, coupled with energy-dispersive X-ray microanalysis. Tissues from Ubá colonized by C. fimbriata had stronger autofluorescence than those from Haden. The X-ray microanalysis revealed that the tissues of Ubá had higher levels of insoluble sulfur and calcium than those of Haden. Scanning electron microscopy revealed that fungal hyphae, chlamydospores (aleurioconidia), and perithecia-like structures of C. fimbriata were more abundant in Haden relative to Ubá. At the ultrastructural level, pathogen hyphae had grown into the degraded walls of parenchyma, fiber cells, and xylem vessels in the tissue of Haden. However, in Ubá, plant cell walls were rarely degraded and hyphae were often surrounded by dense, amorphous granular materials and hyphae appeared to have died. Taken together, the results of this study characterize the susceptible and resistant basal cell responses of mango stem tissue to infection by C. fimbriata.

Intra-discal injection of autologous, hypoxic cultured bone marrow-derived mesenchymal stem cells in five patients with chronic lower back pain: a long-term safety and feasibility study.

PubMed

Elabd, Christian; Centeno, Christopher J; Schultz, John R; Lutz, Gregory; Ichim, Thomas; Silva, Francisco J

2016-09-01

Chronic low back pain due to disc degeneration represents a major social and economic burden worldwide. The current standard of care is limited to symptomatic relief and no current approved therapy promotes disc regeneration. Bone marrow-derived mesenchymal stem cells (MSCs) are easily accessible and well characterized. These MSCs are multipotent and exhibit great tissue regenerative potential including bone, cartilage, and fibrous tissue regeneration. The use of this cell-based biologic for treating protruding disc herniation and/or intervertebral disc degeneration is a promising therapeutic strategy, due to their known regenerative, immuno-modulatory and anti-inflammatory properties. Five patients diagnosed with degenerative disc disease received an intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells (15.1-51.6 million cells) as part of a previous study. These patients were re-consented to participate in this study in order to assess long-term safety and feasibility of intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells 4-6 years post mesenchymal stem cell infusion. The follow-up study consisted of a physical examination, a low back MRI, and a quality of life questionnaire. Patients' lower back MRI showed absence of neoplasms or abnormalities surrounding the treated region. Based on the physical examination and the quality of life questionnaire, no adverse events were reported due to the procedure or to the stem cell treatment 4-6 years post autologous, hypoxic cultured mesenchymal stem cell infusion. All patients self-reported overall improvement, as well as improvement in strength, post stem cell treatment, and four out of five patients reported improvement in mobility. This early human clinical data suggests the safety and feasibility of the clinical use of hypoxic cultured bone marrow-derived mesenchymal stem cells for the treatment of lower back pain due to degenerative disc disorders and support further studies utilizing hypoxic cultured bone marrow-derived stem cells. The overall improvements reported are encouraging, but a larger double-blind, controlled, randomized clinical study with significant number of patients and implementation of validated endpoint measurements are next steps in order to demonstrate efficacy of this cell-based biologic.

Mesenchymal stem cells from adipose and bone marrow promote angiogenesis via distinct cytokine and protease expression mechanisms

PubMed Central

Kachgal, Suraj; Putnam, Andrew J.

2012-01-01

Using a fibrin-based angiogenesis model, we have established that there is no canonical mechanism used by ECs to degrade the surrounding extracellular matrix (ECM), but rather the set of proteases used is dependent on the mural cells providing the angiogenic cues. Mesenchymal stem cells (MSCs) originating from different tissues, which are thought to be phenotypically similar, promote angiogenesis through distinct mechanisms. Specifically, adipose-derived stem cells (ASCs) promote utilization of the plasminogen activator-plasmin axis by ECs as the primary means of vessel invasion and elongation in fibrin. Matrix metalloproteinases (MMPs) serve a purpose in regulating capillary diameter and possibly in stabilizing the nascent vessels. These proteolytic mechanisms are more akin to those involved in fibroblast-mediated angiogenesis than to those in bone marrow-derived stem cell (BMSC)-mediated angiogenesis. In addition, expression patterns of angiogenic factors such as urokinase plasminogen activator (uPA), hepatocyte growth factor (HGF), and tumor necrosis factor alpha (TNFα) were similar for ASC and fibroblast-mediated angiogenesis, and in direct contrast to BMSC-mediated angiogenesis. The present study illustrates that the nature of the heterotypic interactions between mural cells and endothelial cells depend on the identity of the mural cell used. Even MSCs which are shown to behave phenotypically similar do not stimulate angiogenesis via the same mechanisms. PMID:21104120

Engineering the human pluripotent stem cell microenvironment to direct cell fate

PubMed Central

Hazeltine, Laurie B.; Selekman, Joshua A.; Palecek, Sean P.

2013-01-01

Human pluripotent stem cells (hPSCs), including both embryonic stem cells and induced pluripotent stem cells, offer a potential cell source for research, drug screening, and regenerative medicine applications due to their unique ability to self-renew or differentiate to any somatic cell type. Before the full potential of hPSCs can be realized, robust protocols must be developed to direct their fate. Cell fate decisions are based on components of the surrounding microenvironment, including soluble factors, substrate or extracellular matrix, cell-cell interactions, mechanical forces, and 2D or 3D architecture. Depending on their spatio-temporal context, these components can signal hPSCs to either self-renew or differentiate to cell types of the ectoderm, mesoderm, or endoderm. Researchers working at the interface of engineering and biology have identified various factors which can affect hPSC fate, often based on lessons from embryonic development, and they have utilized this information to design in vitro niches which can reproducibly direct hPSC fate. This review highlights culture systems that have been engineered to promote self-renewal or differentiation of hPSCs, with a focus on studies that have elucidated the contributions of specific microenvironmental cues in the context of those culture systems. We propose the use of microsystems technologies for high-throughput screening of spatial-temporal presentation of cues, as this has been demonstrated to be a powerful approach for differentiating hPSCs to desired cell types. PMID:23510904

Engineering the human pluripotent stem cell microenvironment to direct cell fate.

PubMed

Hazeltine, Laurie B; Selekman, Joshua A; Palecek, Sean P

2013-11-15

Human pluripotent stem cells (hPSCs), including both embryonic stem cells and induced pluripotent stem cells, offer a potential cell source for research, drug screening, and regenerative medicine applications due to their unique ability to self-renew or differentiate to any somatic cell type. Before the full potential of hPSCs can be realized, robust protocols must be developed to direct their fate. Cell fate decisions are based on components of the surrounding microenvironment, including soluble factors, substrate or extracellular matrix, cell-cell interactions, mechanical forces, and 2D or 3D architecture. Depending on their spatio-temporal context, these components can signal hPSCs to either self-renew or differentiate to cell types of the ectoderm, mesoderm, or endoderm. Researchers working at the interface of engineering and biology have identified various factors which can affect hPSC fate, often based on lessons from embryonic development, and they have utilized this information to design in vitro niches which can reproducibly direct hPSC fate. This review highlights culture systems that have been engineered to promote self-renewal or differentiation of hPSCs, with a focus on studies that have elucidated the contributions of specific microenvironmental cues in the context of those culture systems. We propose the use of microsystem technologies for high-throughput screening of spatial-temporal presentation of cues, as this has been demonstrated to be a powerful approach for differentiating hPSCs to desired cell types. Copyright © 2013 Elsevier Inc. All rights reserved.

Unexpected severe calcification after transplantation of bone marrow cells in acute myocardial infarction.

PubMed

Yoon, Young-Sup; Park, Jong-Seon; Tkebuchava, Tengiz; Luedeman, Corinne; Losordo, Douglas W

2004-06-29

There has been a rapid increase in the number of clinical trials using unselected bone marrow (BM) cells or the mononuclear fraction of BM cells for treating ischemic heart diseases. Thus far, no significant deleterious effects or complications have been reported in any studies using BM-derived cells for treatment of various cardiac diseases. Seven-week-old female Fisher-344 rats underwent surgery to induce acute myocardial infarction and were randomized into 3 groups of 16 rats, each receiving intramyocardial injection of either 7x10(5) DiI-labeled total BM cells (TBMCs), the same number of DiI-labeled, clonally expanded BM multipotent stem cells, or the same volume of phosphate-buffered saline in the peri-infarct area. Echocardiography 2 weeks after cell transplantation indicated intramyocardial calcification in 4 of 14 surviving rats (28.5%) in the TBMC group. Histological examination with hematoxylin and eosin staining and von Kossa staining confirmed the presence of extensive intramyocardial calcification. Alkaline phosphatase staining revealed strong positivity surrounding the calcified area suggestive of ongoing osteogenic activity. Fluorescent microscopic examination revealed that acellular calcific areas were surrounded by DiI-labeled TBMCs, suggesting the direct involvement of transplanted TBMCs in myocardial calcification. In contrast, in hearts receiving equal volumes of saline or BM multipotent stem cells delivered in the same manner, there was no evidence of calcification. These results demonstrate that direct transplantation of unselected BM cells into the acutely infarcted myocardium may induce significant intramyocardial calcification.

BMP signaling in dermal papilla cells is required for their hair follicle-inductive properties

PubMed Central

Rendl, Michael; Polak, Lisa; Fuchs, Elaine

2008-01-01

Hair follicle (HF) formation is initiated when epithelial stem cells receive cues from specialized mesenchymal dermal papilla (DP) cells. In culture, DP cells lose their HF-inducing properties, but during hair growth in vivo, they reside within the HF bulb and instruct surrounding epithelial progenitors to orchestrate the complex hair differentiation program. To gain insights into the molecular program that maintains DP cell fate, we previously purified DP cells and four neighboring populations and defined their cell-type-specific molecular signatures. Here, we exploit this information to show that the bulb microenvironment is rich in bone morphogenetic proteins (BMPs) that act on DP cells to maintain key signature features in vitro and hair-inducing activity in vivo. By employing a novel in vitro/in vivo hybrid knockout assay, we ablate BMP receptor 1a in purified DP cells. When DPs cannot receive BMP signals, they lose signature characteristics in vitro and fail to generate HFs when engrafted with epithelial stem cells in vivo. These results reveal that BMP signaling, in addition to its key role in epithelial stem cell maintenance and progenitor cell differentiation, is essential for DP cell function, and suggest that it is a critical feature of the complex epithelial–mesenchymal cross-talk necessary to make hair. PMID:18281466

Myogenic Progenitor Cells Control Extracellular Matrix Production by Fibroblasts during Skeletal Muscle Hypertrophy.

PubMed

Fry, Christopher S; Kirby, Tyler J; Kosmac, Kate; McCarthy, John J; Peterson, Charlotte A

2017-01-05

Satellite cells, the predominant stem cell population in adult skeletal muscle, are activated in response to hypertrophic stimuli and give rise to myogenic progenitor cells (MPCs) within the extracellular matrix (ECM) that surrounds myofibers. This ECM is composed largely of collagens secreted by interstitial fibrogenic cells, which influence satellite cell activity and muscle repair during hypertrophy and aging. Here we show that MPCs interact with interstitial fibrogenic cells to ensure proper ECM deposition and optimal muscle remodeling in response to hypertrophic stimuli. MPC-dependent ECM remodeling during the first week of a growth stimulus is sufficient to ensure long-term myofiber hypertrophy. MPCs secrete exosomes containing miR-206, which represses Rrbp1, a master regulator of collagen biosynthesis, in fibrogenic cells to prevent excessive ECM deposition. These findings provide insights into how skeletal stem and progenitor cells interact with other cell types to actively regulate their extracellular environments for tissue maintenance and adaptation. Copyright © 2017 Elsevier Inc. All rights reserved.

The lived experience of autologous stem cell-transplanted patients: Post-transplantation and before discharge.

PubMed

Alnasser, Qasem; Abu Kharmah, Salahel Deen; Attia, Manal; Aljafari, Akram; Agyekum, Felicia; Ahmed, Falak Aftab

2018-04-01

To explore the lived experience of the patients post-haematopoietic stem cell transplantation and specifically after engraftment and before discharge. Patients post-stem cell transplantation experience significant changes in all life aspects. Previous studies carried out by other researchers focused mainly on the postdischarge experience, where patients reported their perceptions that have always been affected by the life post-transplantation and influenced by their surroundings. The lived experience of patients, specifically after engraftment and prior to discharge (the "transition" phase), has not been adequately explored in the literature. Doing so might provide greater insight into the cause of change post-haematopoietic stem cell transplantation. This study is a phenomenological description of the participants' perception about their lived experience post-haematopoietic stem cell transplantation. The study used Giorgi's method of analysis. Through purposive sampling, 15 post-haematopoietic stem cell transplantation patients were recruited. Data were collected by individual interviews. Data were then analysed based on Giorgi's method of analysis to reveal the meaning of a phenomenon as experienced through the identification of essential themes. The analysis process revealed 12 core themes covered by four categories that detailed patients lived experience post-haematopoietic stem cell transplantation. The four categories were general transplant experience, effects of transplantation, factors of stress alleviation and finally life post-transplantation. This study showed how the haematopoietic stem cell transplantation affected the patients' physical, psychological and spiritual well-being. Transplantation also impacted on the patients' way of thinking and perception of life. Attending to patients' needs during transplantation might help to alleviate the severity of the effects and therefore improve experience. Comprehensive information about transplantation needs to be provided over different intervals and at different occasions. The role of the haematopoietic stem cell transplantation coordinators is important, and their communication skills and knowledge were found to be significant in patients' preparation and decision-making. As healthcare providers usually attend to only the patients' physical and psychological needs, spirituality was found to play an important role in maintaining morale and making sense of the meaning of life. © 2018 John Wiley & Sons Ltd.

Human pluripotent stem cells on artificial microenvironments: a high content perspective

PubMed Central

Viswanathan, Priyalakshmi; Gaskell, Terri; Moens, Nathalie; Culley, Oliver J.; Hansen, Darrick; Gervasio, Mia K. R.; Yeap, Yee J.; Danovi, Davide

2014-01-01

Self-renewing stem cell populations are increasingly considered as resources for cell therapy and tools for drug discovery. Human pluripotent stem (hPS) cells in particular offer a virtually unlimited reservoir of homogeneous cells and can be differentiated toward diverse lineages. Many diseases show impairment in self-renewal or differentiation, abnormal lineage choice or other aberrant cell behavior in response to chemical or physical cues. To investigate these responses, there is a growing interest in the development of specific assays using hPS cells, artificial microenvironments and high content analysis. Several hurdles need to be overcome that can be grouped into three areas: (i) availability of robust, homogeneous, and consistent cell populations as a starting point; (ii) appropriate understanding and use of chemical and physical microenvironments; (iii) development of assays that dissect the complexity of cell populations in tissues while mirroring specific aspects of their behavior. Here we review recent progress in the culture of hPS cells and we detail the importance of the environment surrounding the cells with a focus on synthetic material and suitable high content analysis approaches. The technologies described, if properly combined, have the potential to create a paradigm shift in the way diseases are modeled and drug discovery is performed. PMID:25071572

Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model.

PubMed

Qi, Yiying; Du, Yi; Li, Weixu; Dai, Xuesong; Zhao, Tengfei; Yan, Weiqi

2014-06-01

The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model. Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically. The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups. The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.

Gelatinized Copper–Capillary Alginate Gel Functions as an Injectable Tissue Scaffolding System for Stem Cell Transplants

PubMed Central

Willenberg, Bradley Jay; Zheng, Tong; Meng, Fan-Wei; Meneses, Juan Carlos; Rossignol, Candace; Batich, Christopher D.; Terada, Naohiro; Steindler, Dennis A.; Weiss, Michael D.

2013-01-01

In severe hypoxic–ischemic brain injury, cellular components such as neurons and astrocytes are injured or destroyed along with the supporting extracellular matrix. This presents a challenge to the field of regenerative medicine since the lack of extracellular matrix and supporting structures makes the transplant milieu inhospitable to the transplanted cells. A potential solution to this problem is the use of a biomaterial to provide the extracellular components needed to keep cells localized in cystic brain regions, allowing the cells to form connections and repair lost brain tissue. Ideally, this biomaterial would be combined with stem cells, which have been proven to have therapeutic potentials, and could be delivered via an injection. To study this approach, we derived a hydrogel biomaterial tissue scaffold from oligomeric gelatin and copper–capillary alginate gel (GCCAG). We then demonstrated that our multipotent astrocytic stem cells (MASCs) could be maintained in GCCAG scaffolds for up to 2 weeks in vitro and that the cells retained their multipotency. We next performed a pilot transplant study in which GCCAG was mixed with MASCs and injected into the brain of a neonatal rat pup. After a week in vivo, our results showed that: the GCCAG biomaterial did not cause a significant reactive gliosis; viable cells were retained within the injected scaffolds; and some delivered cells migrated into the surrounding brain tissue. Therefore, GCCAG tissue scaffolds are a promising, novel injectable system for transplantation of stem cells to the brain. PMID:20699061

Initial stem cell adhesion on porous silicon surface: molecular architecture of actin cytoskeleton and filopodial growth

PubMed Central

2014-01-01

The way cells explore their surrounding extracellular matrix (ECM) during development and migration is mediated by lamellipodia at their leading edge, acting as an actual motor pulling the cell forward. Lamellipodia are the primary area within the cell of actin microfilaments (filopodia) formation. In this work, we report on the use of porous silicon (pSi) scaffolds to mimic the ECM of mesenchymal stem cells from the dental pulp (DPSC) and breast cancer (MCF-7) cells. Our atomic force microscopy (AFM), fluorescence microscopy, and scanning electron microscopy (SEM) results show that pSi promoted the appearance of lateral filopodia protruding from the DPSC cell body and not only in the lamellipodia area. The formation of elongated lateral actin filaments suggests that pores provided the necessary anchorage points for protrusion growth. Although MCF-7 cells displayed a lower presence of organized actin network on both pSi and nonporous silicon, pSi stimulated the formation of extended cell protrusions. PMID:25386101

Wnt Responsive Lgr5-Expressing Stem Cells Are Hair Cell Progenitors in the Cochlea

PubMed Central

Shi, Fuxin; Kempfle, Judith; Edge, Albert S. B.

2012-01-01

Auditory hair cells are surrounded on their basolateral aspects by supporting cells, and these two cell types together constitute the sensory epithelium of the organ of Corti, which is the hearing apparatus of the ear. We show here that Lgr5, a marker for adult stem cells, was expressed in a subset of supporting cells in the newborn and adult murine cochlea. Lgr5-expressing supporting cells, sorted by flow cytometry and cultured in a single cell suspension, as compared to unsorted cells, displayed an enhanced capacity for self-renewing neurosphere formation in response to Wnt and were converted to hair cells at a higher (>10-fold) rate. The greater differentiation of hair cell in the neurosphere assay showed that Lgr5-positive cells had the capacity to act as cochlear progenitor cells, and lineage tracing confirmed that Lgr5-expressing cells accounted for the cells that formed neurospheres and differentiated to hair cells. The responsiveness to Wnt of cells with a capacity for division and sensory cell formation suggests a potential route to new hair cell generation in the adult cochlea. PMID:22787049

Stem cells from human exfoliated deciduous teeth (SHED) enhance wound healing and the possibility of novel cell therapy.

PubMed

Nishino, Yudai; Yamada, Yoichi; Ebisawa, Katsumi; Nakamura, Sayaka; Okabe, Kazuto; Umemura, Eri; Hara, Kenji; Ueda, Minoru

2011-05-01

In recent years, stem cells from human exfoliated deciduous teeth (SHED) have received attention as a novel stem cell source with multipotent potential. We examined the effect on wound-healing promotion with unique stem cells from deciduous teeth as a medical waste. An excisional wound-splinting mouse model was used and the effect of wound healing among SHED, human mesenchymal stromal cells (hMSCs), human fibroblasts (hFibro) and a control (phosphate-buffered saline; PBS) was evaluated by macroscopy, histology and enzyme-linked immunosorbent assay (ELISA), and the expression of hyaluronan (HA), which is related to wound healing, investigated. SHED and hMSCs accelerated wound healing compared with hFibro and the control. There was a statistically significant difference in wound healing area among hFibro, hMSCs and SHED compared with the control after day 5. At days 7 and 14 after cell transplantation, the histologic observation showed that transplanted PKH26-positive cells were surrounded by human HA binding protein, especially in hMSCs and SHED. HA expression volume values were 1558.41 ± 60.33 (control), 2092.75 ± 42.56 (hFibro), 2342.07 ± 188.10 (hMSCs) and 2314.85 ± 164.91 (SHED) ng/mg, respectively, and significantly higher in hMSCs and SHED compared with hFibro and control at days 7 and 14 (P < 0.05). Our results show that SHED hMSCs have similar effects of wound-healing promotion as hFibro and controls. This implies that SHED might offer a unique stem cell resource and the possibility of novel cell therapies for wound healing in the future.

Blastema cells derived from New Zealand white rabbit's pinna carry stemness properties as shown by differentiation into insulin producing, neural, and osteogenic lineages representing three embryonic germ layers.

PubMed

Saeinasab, Morvarid; Matin, Maryam M; Rassouli, Fatemeh B; Bahrami, Ahmad Reza

2016-05-01

Stem cells (SCs) are known as undifferentiated cells with self-renewal and differentiation capacities. Regeneration is a phenomenon that occurs in a limited number of animals after injury, during which blastema tissue is formed. It has been hypothesized that upon injury, the dedifferentiation of surrounding tissues leads into the appearance of cells with SC characteristics. In present study, stem-like cells (SLCs) were obtained from regenerating tissue of New Zealand white rabbit's pinna and their stemness properties were examined by their capacity to differentiate toward insulin producing cells (IPCs), as well as neural and osteogenic lineages. Differentiation was induced by culture of SLCs in defined medium, and cell fates were monitored by specific staining, RT-PCR and flow cytometry assays. Our results revealed that dithizone positive cells, which represent IPCs, and islet-like structures appeared 1 week after induction of SLCs, and this observation was confirmed by the elevated expression of Ins, Pax6 and Glut4 at mRNA level. Furthermore, SLCs were able to express neural markers as early as 1 week after retinoic acid treatment. Finally, SLCs were able to differentiate into osteogenic lineage, as confirmed by Alizarin Red S staining and RT-PCR studies. In conclusion, SLCs, which could successfully differentiate into cells derived from all three germ layers, can be considered as a valuable model to study developmental biology and regenerative medicine.

Expression of SRY-related HMG Box Transcription Factors (Sox) 2 and 9 in Craniopharyngioma Subtypes and Surrounding Brain Tissue.

PubMed

Thimsen, Vivian; John, Nora; Buchfelder, Michael; Flitsch, Jörg; Fahlbusch, Rudolf; Stefanits, Harald; Knosp, Engelbert; Losa, Marco; Buslei, Rolf; Hölsken, Annett

2017-11-20

Stem cells have been discovered as key players in the genesis of different neoplasms including craniopharyngioma (CP), a rare tumour entity in the sellar region. Sox2 and Sox9 are well-known stem cell markers involved in pituitary development. In this study we analysed the expression of both transcription factors using immunohistochemistry in a large cohort of 64 adamantinomatous (aCP) and 9 papillary CP (pCP) and quantitative PCR in 26 aCP and 7 pCP. Whereas immunohistochemically Sox2+ cells were verifiable in only five aCP (7.8%) and in 39.1% of the respective surrounding cerebral tissue, pCP specimens appeared always negative. In contrast, Sox9 was detectable in all tumours with a significantly higher expression in aCP compared to pCP (protein, p < 0.0001; mRNA p = 0.0484) This was also true for the respective tumour adjacent CNS where 63 aCP (98.4%) and six pCP (66.7%) showed Sox9+ cells. We further confirmed absence of Sox9 expression in nuclear β-catenin accumulating cells of aCP. Our results point to the conclusion that Sox2 and Sox9, seem to play essential roles not only in the specific formation of aCP, but also in processes involving the cerebral tumour environment, which needs to be illuminated in the future.

Ginger Oleoresin Alleviated γ-Ray Irradiation-Induced Reactive Oxygen Species via the Nrf2 Protective Response in Human Mesenchymal Stem Cells

PubMed Central

Ji, Kaihua; Li, Qing; Shi, Yang; Xu, Chang; Wang, Yan; Du, Liqing

2017-01-01

Unplanned exposure to radiation can cause side effects on high-risk individuals; meanwhile, radiotherapies can also cause injury on normal cells and tissues surrounding the tumor. Besides the direct radiation damage, most of the ionizing radiation- (IR-) induced injuries were caused by generation of reactive oxygen species (ROS). Human mesenchymal stem cells (hMSCs), which possess self-renew and multilineage differentiation capabilities, are a critical population of cells to participate in the regeneration of IR-damaged tissues. Therefore, it is imperative to search effective radioprotectors for hMSCs. This study was to demonstrate whether natural source ginger oleoresin would mitigate IR-induced injuries in human mesenchymal stem cells (hMSCs). We demonstrated that ginger oleoresin could significantly reduce IR-induced cytotoxicity, ROS generation, and DNA strand breaks. In addition, the ROS-scavenging mechanism of ginger oleoresin was also investigated. The results showed that ginger oleoresin could induce the translocation of Nrf2 to cell nucleus and activate the expression of cytoprotective genes encoding for HO-1 and NQO-1. It suggests that ginger oleoresin has a potential role of being an effective antioxidant and radioprotective agent. PMID:29181121

Liver stem/progenitor cells in the canals of Hering: cellular origin of hepatocellular carcinoma with bile duct tumor thrombi?

PubMed

Peng, Ningfu; Li, Lequn; Cai, Xiang; Tan, Shaozao; Wu, Ting

2010-12-01

It is generally believed that the invasion of hepatocellular carcinoma (HCC) into the biliary tree ultimately leads to the formation of bile duct tumor thrombi (BDTT). However, recent studies revealed that primary tumor might be small, even undetectable, and there was no histopathologic evidence of direct tumor invasion into bile duct wall in some patients. During the last decade, efforts on stem cell biology may shed light on the pathogenesis of BDTT. Presently, accumulating evidence supports the following notions: (1) the canals of Hering (CoH) are the most likely origin of liver stem/progenitor cells (LSPCs) in adult livers; (2) similar signalling pathways may regulate self-renewal in LSPCs and liver cancer cells, and a substantial proportion of liver tumors may often originate from the transformation of LSPCs; and (3) liver cancer contains rare cells with stem cell-like properties, which could derive from malignant transformation of LSPCs. Herein, we propose that HCC with BDTT, especially with small or undetectable primary lesion and/or no histopathologic evidence for bile duct invasion, might arise from LSPCs residing in the CoH and, possibly, some primary lesions are formed firstly within the intrahepatic biliary tree. When "tumor thrombi" extends mainly along bile duct, there might be "BDTT" alone; when it invades into surrounding parenchyma, there might often be small "primary tumor" with "BDTT". If this holds true, the putative type may be a particular subset of HCC, and most importantly it would facilitate our understanding of stem-cell origin of HCC.

Dental Stem Cell Migration on Pulp Ceiling Cavities Filled with MTA, Dentin Chips, or Bio-Oss

PubMed Central

Lymperi, Stefania; Taraslia, Vasiliki; Tsatsoulis, Ioannis N.; Samara, Athina; Agrafioti, Anastasia; Anastasiadou, Ema; Kontakiotis, Evangelos

2015-01-01

MTA, Bio-Oss, and dentin chips have been successfully used in endodontics. The aim of this study was to assess the adhesion and migration of dental stem cells on human pulp ceiling cavities filled with these endodontic materials in an experimental model, which mimics the clinical conditions of regenerative endodontics. Cavities were formed, by a homemade mold, on untouched third molars, filled with endodontic materials, and observed with electron microscopy. Cells were seeded on cavities' surface and their morphology and number were analysed. The phenomenon of tropism was assessed in a migration assay. All three materials demonstrated appropriate microstructures for cell attachment. Cells grew on all reagents, but they showed a differential morphology. Moreover, variations were observed when comparing cells numbers on cavity's filling versus the surrounding dentine disc. The highest number of cells was recorded on dentin chips whereas the opposite was true for Bio-Oss. This was confirmed in the migration assay where a statistically significant lower number of cells migrated towards Bio-Oss as compared to MTA and dentin chips. This study highlights that MTA and dentin chips have a greater potential compared to Bio-Oss regarding the attraction of dental stem cells and are good candidates for bioengineered pulp regeneration. PMID:26146613

ALS Pathogenesis and Therapeutic Approaches: The Role of Mesenchymal Stem Cells and Extracellular Vesicles.

PubMed

Bonafede, Roberta; Mariotti, Raffaella

2017-01-01

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive muscle paralysis determined by the degeneration of motoneurons in the motor cortex brainstem and spinal cord. The ALS pathogenetic mechanisms are still unclear, despite the wealth of studies demonstrating the involvement of several altered signaling pathways, such as mitochondrial dysfunction, glutamate excitotoxicity, oxidative stress and neuroinflammation. To date, the proposed therapeutic strategies are targeted to one or a few of these alterations, resulting in only a minimal effect on disease course and survival of ALS patients. The involvement of different mechanisms in ALS pathogenesis underlines the need for a therapeutic approach targeted to multiple aspects. Mesenchymal stem cells (MSC) can support motoneurons and surrounding cells, reduce inflammation, stimulate tissue regeneration and release growth factors. On this basis, MSC have been proposed as promising candidates to treat ALS. However, due to the drawbacks of cell therapy, the possible therapeutic use of extracellular vesicles (EVs) released by stem cells is raising increasing interest. The present review summarizes the main pathological mechanisms involved in ALS and the related therapeutic approaches proposed to date, focusing on MSC therapy and their preclinical and clinical applications. Moreover, the nature and characteristics of EVs and their role in recapitulating the effect of stem cells are discussed, elucidating how and why these vesicles could provide novel opportunities for ALS treatment.

Comparative effects of chlorhexidine and essential oils containing mouth rinse on stem cells cultured on a titanium surface.

PubMed

Park, Jun-Beom; Lee, Gil; Yun, Byeong Gon; Kim, Chang-Hyen; Ko, Youngkyung

2014-04-01

Chlorhexidine (CHX) and Listerine (LIS), an essential oil compound, are the two commonly used adjunctive agents for mechanical debridement, for reducing the bacterial load in the treatment of peri-implant inflammation. However, antimicrobial agents have been reported to be cytotoxic to the alveolar bone cells and gingival epithelial cells. The present study was performed to examine the effects of antiseptics CHX and LIS, on the morphology and proliferation of stem cells. Stem cells derived from the buccal fat pad were grown on machined titanium discs. Each disc was immersed in CHX or LIS for 30 sec, 1.5 min or 4.5 min. Cell morphology was evaluated with a confocal laser microscope and the viability of the cells was quantitatively analyzed with the cell counting kit-8 (CCK-8). The untreated cells attached to the titanium discs demonstrated well-organized actin cytoskeletons. No marked alterations in the cytoskeletal organization were observed in any of the treated groups. The treatment with CHX and LIS of the titanium discs decreased the viability of the cells grown on the treated discs (P<0.05). The stem cells derived from the buccal fat pad were sensitive to CHX and LIS, and a reduction in cellular viability was observed when these agents were applied to the discs for 30 sec. Further studies are required to determine the optimal application time and concentration of this antimicrobial agent for maximizing the reduction of the bacterial load and minimizing the cytotoxicity to the surrounding cells.

Carvedilol protects bone marrow stem cells against hydrogen peroxide-induced cell death via PI3K-AKT pathway.

PubMed

Chen, Meihui; Chen, Shudong; Lin, Dingkun

2016-03-01

Carvedilol, a nonselective β-adrenergic receptor blocker, has been reported to exert potent anti-oxidative activities. In the present study, we aimed to investigate the effects of carvedilol against hydrogen peroxide (H2O2)-induced bone marrow-derived mesenchymal stem cells (BMSCs) death, which imitate the microenvironment surrounding transplanted cells in the injured spinal cord in vitro. Carvedilol significantly reduced H2O2-induced reactive oxygen species production, apoptosis and subsequent cell death. LY294002, the PI3K inhibitor, blocked the protective effects and up-regulation of Akt phosphorylation of carvedilol. Together, our results showed that carvedilol protects H2O2-induced BMSCs cell death partly through PI3K-Akt pathway, suggesting carvedilol could be used in combination with BMSCs for the treatment of spinal cord injury by improving the cell survival and oxidative stress microenvironments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance

PubMed Central

Liu, H-X; Ermilov, A; Grachtchouk, M; Li, L; Gumucio, DL; Dlugosz, AA; Mistretta, CM

2014-01-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. PMID:23916850

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance.

PubMed

Liu, Hong Xiang; Ermilov, Alexandre; Grachtchouk, Marina; Li, Libo; Gumucio, Deborah L; Dlugosz, Andrzej A; Mistretta, Charalotte M

2013-10-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. © 2013 Elsevier Inc. All rights reserved.

Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration.

PubMed

Plikus, Maksim V; Mayer, Julie Ann; de la Cruz, Damon; Baker, Ruth E; Maini, Philip K; Maxson, Robert; Chuong, Cheng-Ming

2008-01-17

In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge are regulated by the surrounding microenvironment, or niche. The activation of such stem cells is cyclic, involving periodic beta-catenin activity. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/beta-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug delivery and stem cell engineering studies, because they highlight the acute need to differentiate supportive versus inhibitory regions in the host skin.

Stem cell-dependent formation of a functional anterior regeneration pole in planarians requires Zic and Forkhead transcription factors.

PubMed

Vogg, Matthias C; Owlarn, Suthira; Pérez Rico, Yuvia A; Xie, Jianlei; Suzuki, Yoko; Gentile, Luca; Wu, Wei; Bartscherer, Kerstin

2014-06-15

Planarians can regenerate their head within days. This process depends on the direction of adult stem cells to wound sites and the orchestration of their progenitors to commit to appropriate lineages and to arrange into patterned tissues. We identified a zinc finger transcription factor, Smed-ZicA, as a downstream target of Smed-FoxD, a Forkhead transcription factor required for head regeneration. Smed-zicA and Smed-FoxD are co-expressed with the Wnt inhibitor notum and the Activin inhibitor follistatin in a cluster of cells at the anterior-most tip of the regenerating head - the anterior regeneration pole - and in surrounding stem cell progeny. Depletion of Smed-zicA and Smed-FoxD by RNAi abolishes notum and follistatin expression at the pole and inhibits head formation downstream of initial polarity decisions. We suggest a model in which ZicA and FoxD transcription factors synergize to control the formation of Notum- and Follistatin-producing anterior pole cells. Pole formation might constitute an early step in regeneration, resulting in a signaling center that orchestrates cellular events in the growing tissue. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Deep tissue single cell MSC ablation using a fiber laser source to evaluate therapeutic potential in osteogenesis imperfecta

NASA Astrophysics Data System (ADS)

Tehrani, Kayvan F.; Pendleton, Emily G.; Lin, Charles P.; Mortensen, Luke J.

2016-04-01

Osteogenesis imperfecta (OI) is a currently uncurable disease where a mutation in collagen type I yields brittle bones. One potential therapy is transplantation of mesenchymal stem cells (MSCs), but controlling and enhancing transplanted cell survival has proven challenging. Therefore, we use a 2- photon imaging system to study individual transplanted cells in the living bone marrow. We ablated cells deep in the bone marrow and observed minimal collateral damage to surrounding tissue. Future work will evaluate the local impact of transplanted MSCs on bone deposition in vivo.

Comparative characterization of stromal vascular cells derived from three types of vascular wall and adipose tissue.

PubMed

Yang, Santsun; Eto, Hitomi; Kato, Harunosuke; Doi, Kentaro; Kuno, Shinichiro; Kinoshita, Kahori; Ma, Hsu; Tsai, Chi-Han; Chou, Wan-Ting; Yoshimura, Kotaro

2013-12-01

Multipotent stem/progenitor cells localize perivascularly in many organs and vessel walls. These tissue-resident stem/progenitor cells differentiate into vascular endothelial cells, pericytes, and other mesenchymal lineages, and participate in physiological maintenance and repair of vasculatures. In this study, we characterized stromal vascular cells obtained through the explant culture method from three different vessel walls in humans: arterial wall (ART; >500 μm in diameter), venous wall (VN; >500 μm in diameter), and small vessels in adipose tissue (SV; arterioles and venules, <100 μm in diameter). These were examined for functionality and compared with adipose-derived stem/stromal cells (ASCs). All stromal vascular cells of different origins presented fibroblast-like morphology and we could not visually discriminate one population from another. Flow cytometry showed that the cultured population heterogeneously expressed a variety of surface antigens associated with stem/progenitor cells, but CD105 was expressed by most cells in all groups, suggesting that the cells generally shared the characteristics of mesenchymal stem cells. Our histological and flow cytometric data suggested that the main population of vessel wall-derived stromal vascular cells were CD34(+)/CD31(-) and came from the tunica adventitia and areola tissue surrounding the adventitia. CD271 (p75NTR) was expressed by the vasa vasorum in the VN adventitia and by a limited population in the adventitia of SV. All three populations differentiated into multiple lineages as did ASCs. ART cells induced the largest quantity of calcium formation in the osteogenic medium, whereas ASCs showed the greatest adipogenic differentiation. SV and VN stromal cells had greater potency for network formation than did ART stromal cells. In conclusion, the three stromal vascular populations exhibited differential functional properties. Our results have clinical implications for vascular diseases such as arterial wall calcification and possible applications to regenerative therapies involving each vessel wall-resident stromal population.

In vitro and in vivo assessment of magnetically actuated biomaterials and prospects in tendon healing.

PubMed

Santos, Lívia; Silva, Marta; Gonçalves, Ana I; Pesqueira, Tamagno; Rodrigues, Márcia T; Gomes, Manuela E

2016-05-01

To expand our understanding on the effect of magnetically actuated biomaterials in stem cells, inflammation and fibrous tissue growth. Magnetic biomaterials were obtained by doping iron oxide particles into starch poly-ϵ-caprolactone (SPCL) to create two formulations, magSPCL-1.8 and 3.6. Stem cell behavior was assessed in vitro and the inflammatory response, subcutaneously in Wistar rats. Metabolic activity and proliferation increased significantly overtime in SPCL and magSPCL-1.8. Electromagnetic fields attenuated the presence of mast cells and macrophages in tissues surrounding SPCL and magSPCL-1.8, between weeks 1 and 9. Macrophage reduction was more pronounced for magSPCL-1.8, which could explain why this material prevented growth of fibrous tissue overtime. Magnetically actuated biomaterials have potential to modulate inflammation and the growth of fibrous tissue.

In vitro organogenesis of gut-like structures from mouse embryonic stem cells.

PubMed

Kuwahara, M; Ogaeri, T; Matsuura, R; Kogo, H; Fujimoto, T; Torihashi, S

2004-04-01

Embryonic stem (ES) cells have pluripotency and give rise to many cell types and tissues, including representatives of all three germ layers in the embryo. We have reported previously that mouse ES cells formed contracting gut-like organs from embryoid bodies (EBs). These gut-like structures contracted spontaneously, and had large lumens surrounded by three layers, i.e. epithelium, lamina propria and muscularis. Ganglia were scattered along the periphery, and interstitial cells of Cajal (ICC) were distributed among the smooth muscle cells. In the present study, to determine whether they can be a model of gut organogenesis, we investigated the formation process of the gut-like structures in comparison with embryonic gut development. As a result, we found that the fundamental process of formation in vitro was similar to embryonic gut development in vivo. The result indicates that the gut-like structure is a useful tool not only for developmental study to determine the factors that induce gut organogenesis, but also for studies of enteric neurone and ICC development.

Beller Lectureship Talk: Active response of biological cells to mechanical stress

NASA Astrophysics Data System (ADS)

Safran, Samuel

2009-03-01

Forces exerted by and on adherent cells are important for many physiological processes such as wound healing and tissue formation. In addition, recent experiments have shown that stem cell differentiation is controlled, at least in part, by the elasticity of the surrounding matrix. We present a simple and generic theoretical model for the active response of biological cells to mechanical stress. The theory includes cell activity and mechanical forces as well as random forces as factors that determine the polarizability that relates cell orientation to stress. This allows us to explain the puzzling observation of parallel (or sometimes random) alignment of cells for static and quasi-static stresses and of nearly perpendicular alignment for dynamically varying stresses. In addition, we predict the response of the cellular orientation to a sinusoidally varying applied stress as a function of frequency and compare the theory with recent experiments. The dependence of the cell orientation angle on the Poisson ratio of the surrounding material distinguishes cells whose activity is controlled by stress from those controlled by strain. We have extended the theory to generalize the treatment of elastic inclusions in solids to ''living'' inclusions (cells) whose active polarizability, analogous to the polarizability of non-living matter, results in the feedback of cellular forces that develop in response to matrix stresses. We use this to explain recent observations of the non-monotonic dependence of stress-fiber polarization in stem cells on matrix rigidity. These findings provide a mechanical correlate for the existence of an optimal substrate elasticity for cell differentiation and function. [3pt] *In collaboration with R. De (Brown University), Y. Biton (Weizmann Institute), and A. Zemel (Hebrew University) and the experimental groups: Max Planck Institute, Stuttgart: S. Jungbauer, R. Kemkemer, J. Spatz; University of Pennsylvania: A. Brown, D. Discher, F. Rehfeldt.

Regulation of Ovarian Cancer Stem Cells or Tumor-Initiating Cells

PubMed Central

Kwon, Mi Jeong; Shin, Young Kee

2013-01-01

Cancer stem cells or tumor-initiating cells (CSC/TICs), which can undergo self-renewal and differentiation, are thought to play critical roles in tumorigenesis, therapy resistance, tumor recurrence and metastasis. Tumor recurrence and chemoresistance are major causes of poor survival rates of ovarian cancer patients, which may be due in part to the existence of CSC/TICs. Therefore, elucidating the molecular mechanisms responsible for the ovarian CSC/TICs is required to develop a cure for this malignancy. Recent studies have indicated that the properties of CSC/TICs can be regulated by microRNAs, genes and signaling pathways which also function in normal stem cells. Moreover, emerging evidence suggests that the tumor microenvironments surrounding CSC/TICs are crucial for the maintenance of these cells. Similarly, efforts are now being made to unravel the mechanism involved in the regulation of ovarian CSC/TICs, although much work is still needed. This review considers recent advances in identifying the genes and pathways involved in the regulation of ovarian CSC/TICs. Furthermore, current approaches targeting ovarian CSC/TICs are described. Targeting both CSC/TICs and bulk tumor cells is suggested as a more effective approach to eliminating ovarian tumors. Better understanding of the regulation of ovarian CSC/TICs might facilitate the development of improved therapeutic strategies for recurrent ovarian cancer. PMID:23528891

Blastocyst-like structures generated solely from stem cells.

PubMed

Rivron, Nicolas C; Frias-Aldeguer, Javier; Vrij, Erik J; Boisset, Jean-Charles; Korving, Jeroen; Vivié, Judith; Truckenmüller, Roman K; van Oudenaarden, Alexander; van Blitterswijk, Clemens A; Geijsen, Niels

2018-05-01

The blastocyst (the early mammalian embryo) forms all embryonic and extra-embryonic tissues, including the placenta. It consists of a spherical thin-walled layer, known as the trophectoderm, that surrounds a fluid-filled cavity sheltering the embryonic cells 1 . From mouse blastocysts, it is possible to derive both trophoblast 2 and embryonic stem-cell lines 3 , which are in vitro analogues of the trophectoderm and embryonic compartments, respectively. Here we report that trophoblast and embryonic stem cells cooperate in vitro to form structures that morphologically and transcriptionally resemble embryonic day 3.5 blastocysts, termed blastoids. Like blastocysts, blastoids form from inductive signals that originate from the inner embryonic cells and drive the development of the outer trophectoderm. The nature and function of these signals have been largely unexplored. Genetically and physically uncoupling the embryonic and trophectoderm compartments, along with single-cell transcriptomics, reveals the extensive inventory of embryonic inductions. We specifically show that the embryonic cells maintain trophoblast proliferation and self-renewal, while fine-tuning trophoblast epithelial morphogenesis in part via a BMP4/Nodal-KLF6 axis. Although blastoids do not support the development of bona fide embryos, we demonstrate that embryonic inductions are crucial to form a trophectoderm state that robustly implants and triggers decidualization in utero. Thus, at this stage, the nascent embryo fuels trophectoderm development and implantation.

Repair of full-thickness cartilage defects with cells of different origin in a rabbit model.

PubMed

Yan, Hui; Yu, Changlong

2007-02-01

The purpose of this study was to evaluate the repaired tissues formed in full-thickness cartilage defects in a rabbit model implanted with 4 types of chondrogenic cells, including chondrocytes, mesenchymal stem cells (MSCs) and fibroblasts from rabbit, and human umbilical cord blood (hUCB) stem cells. Chondrocytes, MSCs, and fibroblasts were isolated from 6-week-old New Zealand rabbits; hUCB stem cells were isolated from the umbilical cord blood of newborn children. These 4 types of cells were cultured in vitro and embedded in polylactic acid (PLA) matrices. Full-thickness defects were produced in the femoral trochlear grooves of both knees in 36 adult New Zealand White rabbits. Cell/PLA composites were transplanted into cartilage defects. A total of 5 groups were formed according to implanted cell type: Group A, chondrocytes; Group B, MSCs; Group C, fibroblasts; Group D, hUCB stem cells; and Group E, no cells (control group). Repaired tissues were evaluated grossly, histologically, and immunohistochemically at 6 weeks and 12 weeks after implantation. In Groups A and B, defects were repaired with hyaline-like cartilage. In Group C, defects were repaired with fibrous tissue. In Group D, defects were repaired primarily with fibrous tissue and scattered chondrocytes; in some specimens, defects were repaired with a thin layer of hyaline-like cartilage at 12 weeks. In Group E, defects were repaired with fibrous tissue. Histologic scores in Groups A and B were significantly higher than those in Groups C, D, and E at 6 and 12 weeks after transplantation. Full-thickness cartilage defects treated with chondrocyte or MSC transplantation were repaired with hyaline-like cartilage tissue, and repair was significantly better than in tissues treated with fibroblasts and hUCB stem cells, as well as in the control group. Repaired tissues treated with MSCs appeared to have better cell arrangement, subchondral bone remodeling, and integration with surrounding cartilage than did repaired tissues generated by chondrocyte implantation. MSCs might be the most suitable cell source for cartilage repair. Further investigation into hUCB stem cell transplantation is needed. In our study of rabbits, MSCs supplied the most promising cell source for cartilage repair.

Biomechanics of stem cells

NASA Astrophysics Data System (ADS)

Spector, A. A.; Yuan, D.; Somers, S.; Grayson, W. L.

2018-04-01

Stem cells play a key role in the healthy development and maintenance of organisms. They are also critically important in medical treatments of various diseases. It has been recently demonstrated that the mechanical factors such as forces, adhesion, stiffness, relaxation, etc. have significant effects on stem cell functions. Under physiological conditions, cells (stem cells) in muscles, heart, and blood vessels are under the action of externally applied strains. We consider the stem cell microenvironment and performance associated with their conversion (differentiation) into skeletal muscle cells. Two problems are studied by using mathematical models whose parameters are then optimized by fitting experiments. First, we present our analysis of the process of stem cell differentiation under the application of cyclic unidirectional strain. This process is interpreted as a transition through several (six) stages where each of them is defined in terms of expression of a set of factors typical to skeletal muscle cells. The stem cell evolution toward muscle cells is described by a system of nonlinear ODEs. The parameters of the model are determined by fitting the experimental data on the time course of expression of the factors under consideration. Second, we analyse the mechanical (relaxation) properties of a scaffold that serves as the microenvironment for stem cells differentiation into skeletal muscle cells. This scaffold (surrounded by a liquid solution) is composed of unidirectional fibers with pores between them. The relaxation properties of the scaffold are studied in an experiment where a long cylindrical specimen is loaded by the application of ramp displacement until the strain reaches a prescribed value. The magnitude of the corresponding load is recorded. The specimen is considered as transversely isotropic poroelastic cylinder whose force relaxation is associated with liquid diffusion through the pores. An analytical solution for the total force applied to the cylinder in terms of the mechanical properties of the scaffold (longitudinal and lateral Young’s moduli, two Poisson’s ratios, and typical time of liquid diffusion) is used. The number of constant is then reduced to three by estimating the longitudinal Young’s modulus and one of Poisson’s ratios from an earlier experiment. Finally, three remaining parameters are estimated by fitting the relaxation curve corresponding to strain rate of loading of 0.01 s‑1. The developed mathematical solution is then tested by comparing the theoretical and experimental results for another strain rate of 0.0025 s‑1. The scaffold relaxation properties can be important for differentiation of stem cells inside the pores.

Arthroscopic Harvest of Adipose-Derived Mesenchymal Stem Cells From the Infrapatellar Fat Pad.

PubMed

Dragoo, Jason L; Chang, Wenteh

2017-11-01

The successful isolation of adipose-derived mesenchymal stem cells (ADSCs) from the arthroscopically harvested infrapatellar fat pad (IFP) would provide orthopaedic surgeons with an autologous solution for regenerative procedures. To demonstrate the quantity and viability of the mesenchymal stem cell population arthroscopically harvested from the IFP as well as the surrounding synovium. Descriptive laboratory study. The posterior border of the IFP, including the surrounding synovial tissue, was harvested arthroscopically from patients undergoing anterior cruciate ligament reconstruction. Tissue was then collected in an AquaVage adipose canister, followed by fat fractionization using syringe emulsification and concentration with an AdiPrep device. In the laboratory, the layers of tissue were separated and then digested with 0.3% type I collagenase. The pelleted stromal vascular fraction (SVF) cells were then immediately analyzed for viability, mesenchymal cell surface markers by fluorescence-activated cell sorting, and clonogenic capacity. After culture expansion, the metabolic activity of the ADSCs was assessed by an AlamarBlue assay, and the multilineage differentiation capability was tested. The transition of surface antigens from the SVF toward expanded ADSCs at passage 2 was further evaluated. SVF cells were successfully harvested with a mean yield of 4.86 ± 2.64 × 10 5 cells/g of tissue and a mean viability of 69.03% ± 10.75%, with ages ranging from 17 to 52 years (mean, 35.14 ± 13.70 years; n = 7). The cultured ADSCs composed a mean 5.85% ± 5.89% of SVF cells with a mean yield of 0.33 ± 0.42 × 10 5 cells/g of tissue. The nonhematopoietic cells (CD45 - ) displayed the following surface antigens as a percentage of the viable population: CD44 + (52.21% ± 4.50%), CD73 + CD90 + CD105 + (19.20% ± 17.04%), and CD44 + CD73 + CD90 + CD105 + (15.32% ± 15.23%). There was also a significant increase in the expression of ADSC markers CD73 (96.97% ± 1.72%; P < .01), CD10 (84.47% ± 15.46%; P < .05), and CD166 (11.63% ± 7.84%; P < .005) starting at passage 2 compared with freshly harvested SVF cells. The clonogenic efficiency of SVF cells was determined at a mean 3.21% ± 1.52% for layer 1 and 1.51% ± 0.55% for layer 2. Differentiation into cartilage, fat, and bone tissue was demonstrated by tissue-specific staining and quantitative polymerase chain reaction. SVF cells from the IFP and adjacent synovial tissue were successfully harvested using an arthroscopic technique and produced ADSCs with surface markers that meet criteria for defined mesenchymal stem cells. An autologous source of stem cells can now be harvested using a simple arthroscopic technique that will allow orthopaedic surgeons easier access to progenitor cells for regenerative procedures.

PHABULOSA Controls the Quiescent Center-Independent Root Meristem Activities in Arabidopsis thaliana

PubMed Central

Sebastian, Jose; Ryu, Kook Hui; Zhou, Jing; Tarkowská, Danuše; Tarkowski, Petr; Cho, Young-Hee; Yoo, Sang-Dong; Kim, Eun-Sol; Lee, Ji-Young

2015-01-01

Plant growth depends on stem cell niches in meristems. In the root apical meristem, the quiescent center (QC) cells form a niche together with the surrounding stem cells. Stem cells produce daughter cells that are displaced into a transit-amplifying (TA) domain of the root meristem. TA cells divide several times to provide cells for growth. SHORTROOT (SHR) and SCARECROW (SCR) are key regulators of the stem cell niche. Cytokinin controls TA cell activities in a dose-dependent manner. Although the regulatory programs in each compartment of the root meristem have been identified, it is still unclear how they coordinate one another. Here, we investigate how PHABULOSA (PHB), under the posttranscriptional control of SHR and SCR, regulates TA cell activities. The root meristem and growth defects in shr or scr mutants were significantly recovered in the shr phb or scr phb double mutant, respectively. This rescue in root growth occurs in the absence of a QC. Conversely, when the modified PHB, which is highly resistant to microRNA, was expressed throughout the stele of the wild-type root meristem, root growth became very similar to that observed in the shr; however, the identity of the QC was unaffected. Interestingly, a moderate increase in PHB resulted in a root meristem phenotype similar to that observed following the application of high levels of cytokinin. Our protoplast assay and transgenic approach using ARR10 suggest that the depletion of TA cells by high PHB in the stele occurs via the repression of B-ARR activities. This regulatory mechanism seems to help to maintain the cytokinin homeostasis in the meristem. Taken together, our study suggests that PHB can dynamically regulate TA cell activities in a QC-independent manner, and that the SHR-PHB pathway enables a robust root growth system by coordinating the stem cell niche and TA domain. PMID:25730098

Isogenic blood-brain barrier models based on patient-derived stem cells display inter-individual differences in cell maturation and functionality.

PubMed

Patel, Ronak; Page, Shyanne; Al-Ahmad, Abraham Jacob

2017-07-01

The blood-brain barrier (BBB) constitutes an important component of the neurovascular unit formed by specialized brain microvascular endothelial cells (BMECs) surrounded by astrocytes, pericytes, and neurons. Recently, isogenic in vitro models of the BBB based on human pluripotent stem cells have been documented, yet the impact of inter-individual variability on the yield and phenotype of such models remains to be documented. In this study, we investigated the impact of inter-individual variability on the yield and phenotype of isogenic models of the BBB, using patient-derived induced pluripotent stem cells (iPSCs). Astrocytes, BMECs, and neurons were differentiated from four asymptomatic patient-derived iPSCs (two males, two females). We differentiated such cells using existing differentiation protocols and quantified expression of cell lineage markers, as well as BBB phenotype, barrier induction, and formation of neurite processes. iPSC-derived BMECs showed barrier properties better than hCMEC/D3 monolayers; however, we noted differences in the expression and activity among iPSC lines. In addition, we noted differences in the differentiation efficiency of these cells into neural stem cells and progenitor cells (as noted by differences in expression of cell lineage markers). Such differences were reflected later in the terminal differentiation, as seen as ability to induce barrier function and to form neurite processes. Although we demonstrated our ability to obtain an isogenic model of the BBB with different patients' iPSCs, we also noted subtle differences in the expression of cell lineage markers and cell maturation processes, suggesting the presence of inter-individual polymorphisms. © 2017 International Society for Neurochemistry.

Transplantation of embryonic stem cells improves nerve repair and functional recovery after severe sciatic nerve axotomy in rats.

PubMed

Cui, Lin; Jiang, Jun; Wei, Ling; Zhou, Xin; Fraser, Jamie L; Snider, B Joy; Yu, Shan Ping

2008-05-01

Extensive research has focused on transplantation of pluripotent stem cells for the treatment of central nervous system disorders, the therapeutic potential of stem cell therapy for injured peripheral nerves is largely unknown. We used a rat sciatic nerve transection model to test the ability of implanted embryonic stem (ES) cell-derived neural progenitor cells (ES-NPCs) in promoting repair of a severely injured peripheral nerve. Mouse ES cells were neurally induced in vitro; enhanced expression and/or secretion of growth factors were detected in differentiating ES cells. One hour after removal of a 1-cm segment of the left sciatic nerve, ES-NPCs were implanted into the gap between the nerve stumps with the surrounding epineurium as a natural conduit. The transplantation resulted in substantial axonal regrowth and nerve repair, which were not seen in culture medium controls. One to 3 months after axotomy, co-immunostaining with the mouse neural cell membrane specific antibody M2/M6 and the Schwann cell marker S100 suggested that transplanted ES-NPCs had survived and differentiated into myelinating cells. Regenerated axons were myelinated and showed a uniform connection between proximal and distal stumps. Nerve stumps had near normal diameter with longitudinally oriented, densely packed Schwann cell-like phenotype. Fluoro-Gold retrogradely labeled neurons were found in the spinal cord (T12-13) and DRG (L4-L6), suggesting reconnection of axons across the transection. Electrophysiological recordings showed functional activity recovered across the injury gap. These data suggest that transplanted neurally induced ES cells differentiate into myelin-forming cells and provide a potential therapy for severely injured peripheral nerves.

“Engineering Substrate Micro- and Nanotopography to Control Cell Function”

PubMed Central

Bettinger, Christopher J; Langer, Robert; Borenstein, Jeffrey T

2010-01-01

Lead-In The interaction of mammalian cells with nanoscale topography has proven to be an important signaling modality in controlling cell function. Naturally occurring nanotopographic structures within the extracellular matrix present surrounding cells with mechanotransductive cues that influence local migration, cell polarization, and other functions. Synthetically nanofabricated topography can also influence cell morphology, alignment, adhesion, migration, proliferation, and cytoskeleton organization. Here we review the use of in vitro synthetic cell-nanotopography interactions to control cell behavior and influence complex cellular processes including stem cell differentiation and tissue organization. Future challenges and opportunities in cell-nanotopography engineering will also be discussed including the elucidation of mechanisms and applications in tissue engineering. PMID:19492373

Fetal cell carcinogenesis of the thyroid: a modified theory based on recent evidence.

PubMed

Takano, Toru

2014-01-01

Thyroid cancer cells were believed to be generated by multi-step carcinogenesis, in which cancer cells are derived from thyrocytes, via multiple incidences of damage to their genome, especially in oncogenes or anti-oncogenes that accelerate proliferation or foster malignant phenotypes, such as the ability to invade the surrounding tissue or metastasize to distant organs, until a new hypothesis, fetal cell carcinogenesis, was presented. In fetal cell carcinogenesis, thyroid tumor cells are assumed to be derived from three types of fetal thyroid cell which only exist in fetuses or young children, namely, thyroid stem cells (TSCs), thyroblasts and prothyrocytes, by proliferation without differentiation. Genomic alternations, such as RET/PTC and PAX8-PPARγ1 rearrangements and a mutation in the BRAF gene, play an oncogenic role by preventing thyroid fetal cells from differentiating. Fetal cell carcinogenesis effectively explains recent molecular and clinical evidence regarding thyroid cancer, including thyroid cancer initiating cells (TCICs), and it underscores the importance of identifying a stem cells and clarifying the molecular mechanism of organ development in cancer research. It introduces three important concepts, the reverse approach, stem cell crisis and mature and immature cancers. Further, it implies that analysis of a small population of cells in a cancer tissue will be a key technique in establishing future laboratory tests. In the contrary, mass analysis such as gene expression profiling, whole genomic scan, and proteomics analysis may have definite limitations since they can only provide information based on many cells.

Growth dynamics and cytoskeleton organization during stem maturation and gravity-induced stem bending in Zea mays L

NASA Technical Reports Server (NTRS)

Collings, D. A.; Winter, H.; Wyatt, S. E.; Allen, N. S.; Davies, E. (Principal Investigator)

1998-01-01

Characterization of gravitropic bending in the maize stem pulvinus, a tissue that functions specifically in gravity responses, demonstrates that the pulvinus is an ideal system for studying gravitropism. Gravistimulation during the second of three developmental phases of the pulvinus induces a gradient of cell elongation across the non-growing cells of the pulvinus, with the most elongation occurring on the lower side. This cell elongation is spatially and temporally separated from normal internodal cell elongation. The three characterized growth phases in the pulvinus correspond closely to a specialized developmental sequence in which structural features typical of cells not fully matured are retained while cell maturation occurs in surrounding internodal and nodal tissue. For example, the lignification of supporting tissue and rearrangement of transverse microtubules to oblique that occur in the internode when cell elongation ceases are delayed for up to 10 d in the adjacent cells of the pulvinus, and only occurs as a pulvinus loses its capacity to respond to gravistimulation. Gravistimulation does not modify this developmental sequence. Neither wall lignification nor rearrangement of transverse microtubules occurs in the rapidly elongating lower side or non-responsive upper side of the pulvinus until the pulvinus loses the capacity to bend further. Gravistimulation does, however, lead to the formation of putative pit fields within the expanding cells of the pulvinus.

Two-Step Functional Innovation of the Stem-Cell Factors WUS/WOX5 during Plant Evolution

PubMed Central

Zhang, Yuzhou; Jiao, Yue; Jiao, Hengwu

2017-01-01

WUS and WOX5, which are expressed, respectively, in the organizing center (OC) and the quiescent center (QC), are essential for shoot/root apical stem-cell maintenance in flowering plants. However, little is known about how these stem-cell factors evolved their functions in flowering plants. Here, we show that the WUS/WOX5 proteins acquired two distinct capabilities by a two-step functional innovation process in the course of plant evolution. The first-step is the apical stem-cell maintenance activity of WUS/WOX5, which originated in the common ancestor of ferns and seed plants, as evidenced by the interspecies complementation experiments, showing that ectopic expression of fern Ceratopteris richardii WUS-like (CrWUL) surrounding OC/QC, or exclusive OC-/QC-expressed gymnosperms/angiosperms WUS/WOX5 in Arabidopsis wus-1 and wox5-1 mutants, could rescue their phenotypes. The second-step is the intercellular mobility that emerged in the common ancestor of seed plants after divergence from the ferns. Evidence for this includes confocal imaging of GFP fusion proteins, showing that WUS/WOX5 from seed plants, rather than from the fern CrWUL, can migrate into cells adjacent to the OC/QC. Evolutionary analysis showed that the WUS-like gene was duplicated into two copies prior to the divergence of gymnosperms/angiosperms. Then the two gene copies (WUS and WOX5) have undergone similar levels of purifying selection, which is consistent with their conserved functions in angiosperm shoot/root stem-cell maintenance and floral organ formation. Our results highlight the critical roles and the essential prerequisites that the two-step functional innovation of these genes performs and represents in the origin of flowering plants. PMID:28053005

Analyzing pERK Activation During Planarian Regeneration.

PubMed

Fraguas, Susanna; Umesono, Yoshihiko; Agata, Kiyokazu; Cebrià, Francesc

2017-01-01

Planarians are an ideal model in which to study stem cell-based regeneration. After amputation, planarian pluripotent stem cells surrounding the wound proliferate to produce the regenerative blastema, in which they differentiate into the missing tissues and structures. Recent independent studies in planarians have shown that Smed-egfr-3, a gene encoding a homologue of epidermal growth factor (EGF) receptors, and DjerkA, which encodes an extracellular signal-regulated kinase (ERK), may control cell differentiation and blastema growth. However, because these studies were carried in two different planarian species, the relationship between these two genes remains unclear. We have optimized anti-pERK immunostaining in Schmidtea mediterranea using the original protocol developed in Dugesia japonica. Both protocols are reported here as most laboratories worldwide work with one of these two species. Using this protocol we have determined that Smed-egfr-3 appears to be necessary for pERK activation during planarian regeneration.

Development and Stem Cells of the Esophagus

PubMed Central

Zhang, Yongchun; Jiang, Ming; Kim, Eugene; Lin, Sijie; Liu, Kuancan; Lan, Xiaopeng; Que, Jianwen

2017-01-01

The esophagus is derived from the anterior portion of the developmental intermediate foregut, a structure that also gives rise to other organs including the trachea, lung, and stomach. Genetic studies have shown that multiple signaling pathways (e.g. Bmp) and transcription factors (e.g. SOX2) are required for the separation of the esophagus from the neighboring respiratory system. Notably, some of these signaling pathways and transcription factors continue to play essential roles in the subsequent morphogenesis of the esophageal epithelium which undergoes a simple columnar-to-stratified squamous conversion. Reactivation of the relevant signaling pathways has also been associated with pathogenesis of esophageal diseases that affect the epithelium and its stem cells in adults. In this review we will summarize these findings. We will also discuss new data regarding the cell-of-origin for the striated and smooth muscles surrounding the esophagus and how they are differentiated from the mesenchyme during development. PMID:28007661

Investigating Preservice STEM Teacher Conceptions of STEM Education

ERIC Educational Resources Information Center

Radloff, Jeff; Guzey, Selcen

2016-01-01

Surrounding the national emphasis on improving STEM education, effective STEM educators are required. Connected, yet often overlooked, is the need for effective preservice STEM teaching instruction for incoming educators. At a basic level, preservice STEM teacher education should include STEM content, pedagogy, and conceptualization. However, the…

Core-shell designed scaffolds for drug delivery and tissue engineering.

PubMed

Perez, Roman A; Kim, Hae-Won

2015-07-01

Scaffolds that secure and deliver therapeutic ingredients like signaling molecules and stem cells hold great promise for drug delivery and tissue engineering. Employing a core-shell design for scaffolds provides a promising solution. Some unique methods, such as co-concentric nozzle extrusion, microfluidics generation, and chemical confinement reactions, have been successful in producing core-shelled nano/microfibers and nano/microspheres. Signaling molecules and drugs, spatially allocated to the core and/or shell part, can be delivered in a controllable and sequential manner for optimal therapeutic effects. Stem cells can be loaded within the core part on-demand, safely protected from the environments, which ultimately affords ex vivo culture and in vivo tissue engineering. The encapsulated cells experience three-dimensional tissue-mimic microenvironments in which therapeutic molecules are secreted to the surrounding tissues through the semi-permeable shell. Tuning the material properties of the core and shell, changing the geometrical parameters, and shaping them into proper forms significantly influence the release behaviors of biomolecules and the fate of the cells. This topical issue highlights the immense usefulness of core-shell designs for the therapeutic actions of scaffolds in the delivery of signaling molecules and stem cells for tissue regeneration and disease treatment. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biological Characteristics of Fluorescent Superparamagnetic Iron Oxide Labeled Human Dental Pulp Stem Cells

PubMed Central

Li, Ming-wei; Bai, Yu; Guo, Hui-hui

2017-01-01

Tracking transplanted stem cells is necessary to clarify cellular properties and improve transplantation success. In this study, we investigate the effects of fluorescent superparamagnetic iron oxide particles (SPIO) (Molday ION Rhodamine-B™, MIRB) on biological properties of human dental pulp stem cells (hDPSCs) and monitor hDPSCs in vitro and in vivo using magnetic resonance imaging (MRI). Morphological analysis showed that intracellular MIRB particles were distributed in the cytoplasm surrounding the nuclei of hDPSCs. 12.5–100 μg/mL MIRB all resulted in 100% labeling efficiency. MTT showed that 12.5–50 μg/mL MIRB could promote cell proliferation and MIRB over 100 μg/mL exhibited toxic effect on hDPSCs. In vitro MRI showed that 1 × 106 cells labeled with various concentrations of MIRB (12.5–100 μg/mL) could be visualized. In vivo MRI showed that transplanted cells could be clearly visualized up to 60 days after transplantation. These results suggest that 12.5–50 μg/mL MIRB is a safe range for labeling hDPSCs. MIRB labeled hDPSCs cell can be visualized by MRI in vitro and in vivo. These data demonstrate that MIRB is a promising candidate for hDPSCs tracking in hDPSCs based dental pulp regeneration therapy. PMID:28298928

Cell Wall Modifications in Arabidopsis Plants with Altered α-l-Arabinofuranosidase Activity[C][W

PubMed Central

Chávez Montes, Ricardo A.; Ranocha, Philippe; Martinez, Yves; Minic, Zoran; Jouanin, Lise; Marquis, Mélanie; Saulnier, Luc; Fulton, Lynette M.; Cobbett, Christopher S.; Bitton, Frédérique; Renou, Jean-Pierre; Jauneau, Alain; Goffner, Deborah

2008-01-01

Although cell wall remodeling is an essential feature of plant growth and development, the underlying molecular mechanisms are poorly understood. This work describes the characterization of Arabidopsis (Arabidopsis thaliana) plants with altered expression of ARAF1, a bifunctional α-l-arabinofuranosidase/β-d-xylosidase (At3g10740) belonging to family 51 glycosyl-hydrolases. ARAF1 was localized in several cell types in the vascular system of roots and stems, including xylem vessels and parenchyma cells surrounding the vessels, the cambium, and the phloem. araf1 T-DNA insertional mutants showed no visible phenotype, whereas transgenic plants that overexpressed ARAF1 exhibited a delay in inflorescence emergence and altered stem architecture. Although global monosaccharide analysis indicated only slight differences in cell wall composition in both mutant and overexpressing lines, immunolocalization experiments using anti-arabinan (LM6) and anti-xylan (LM10) antibodies indicated cell type-specific alterations in cell wall structure. In araf1 mutants, an increase in LM6 signal intensity was observed in the phloem, cambium, and xylem parenchyma in stems and roots, largely coinciding with ARAF1 expression sites. The ectopic overexpression of ARAF1 resulted in an increase in LM10 labeling in the secondary walls of interfascicular fibers and xylem vessels. The combined ARAF1 gene expression and immunolocalization studies suggest that arabinan-containing pectins are potential in vivo substrates of ARAF1 in Arabidopsis. PMID:18344421

Mesenchymal stem cells: environmentally responsive therapeutics for regenerative medicine

PubMed Central

Murphy, Matthew B; Moncivais, Kathryn; Caplan, Arnold I

2013-01-01

Mesenchymal stem cells (MSCs) are partially defined by their ability to differentiate into tissues including bone, cartilage and adipose in vitro, but it is their trophic, paracrine and immunomodulatory functions that may have the greatest therapeutic impact in vivo. Unlike pharmaceutical treatments that deliver a single agent at a specific dose, MSCs are site regulated and secrete bioactive factors and signals at variable concentrations in response to local microenvironmental cues. Significant progress has been made in understanding the biochemical and metabolic mechanisms and feedback associated with MSC response. The anti-inflammatory and immunomodulatory capacity of MSC may be paramount in the restoration of localized or systemic conditions for normal healing and tissue regeneration. Allogeneic MSC treatments, categorized as a drug by regulatory agencies, have been widely pursued, but new studies demonstrate the efficacy of autologous MSC therapies, even for individuals affected by a disease state. Safety and regulatory concerns surrounding allogeneic cell preparations make autologous and minimally manipulated cell therapies an attractive option for many regenerative, anti-inflammatory and autoimmune applications. PMID:24232253

Functional cortical neurons and astrocytes from human pluripotent stem cells in 3D culture.

PubMed

Paşca, Anca M; Sloan, Steven A; Clarke, Laura E; Tian, Yuan; Makinson, Christopher D; Huber, Nina; Kim, Chul Hoon; Park, Jin-Young; O'Rourke, Nancy A; Nguyen, Khoa D; Smith, Stephen J; Huguenard, John R; Geschwind, Daniel H; Barres, Ben A; Paşca, Sergiu P

2015-07-01

The human cerebral cortex develops through an elaborate succession of cellular events that, when disrupted, can lead to neuropsychiatric disease. The ability to reprogram somatic cells into pluripotent cells that can be differentiated in vitro provides a unique opportunity to study normal and abnormal corticogenesis. Here, we present a simple and reproducible 3D culture approach for generating a laminated cerebral cortex-like structure, named human cortical spheroids (hCSs), from pluripotent stem cells. hCSs contain neurons from both deep and superficial cortical layers and map transcriptionally to in vivo fetal development. These neurons are electrophysiologically mature, display spontaneous activity, are surrounded by nonreactive astrocytes and form functional synapses. Experiments in acute hCS slices demonstrate that cortical neurons participate in network activity and produce complex synaptic events. These 3D cultures should allow a detailed interrogation of human cortical development, function and disease, and may prove a versatile platform for generating other neuronal and glial subtypes in vitro.

Mutant Ataxin-1 Inhibits Neural Progenitor Cell Proliferation in SCA1

PubMed Central

Cvetanovic, Marija; Hu, Yuan-Shih; Opal, Puneet

2017-01-01

Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by the expansion of a polyglutamine (Q) repeat tract in the protein ataxin-1 (ATXN1). Beginning as a cerebellar ataxic disorder, SCA1 progresses to involve the cerebral cortex, hippocampus, and brainstem. Using SCA1 knock-in mice that mirror the complexity of the human disease, we report a significant decrease in the capacity of adult neuronal progenitor cells (NPCs) to proliferate. Remarkably, a decrease in NPCs proliferation can be observed in vitro, outside the degenerative milieu of surrounding neurons or glia, demonstrating that mutant ATXN1 acting cell autonomously within progenitor cells interferes with their ability to proliferate. Our findings suggest that compromised adult neurogenesis contributes to the progressive pathology of the disease particularly in areas such as the hippocampus and cerebral cortex where stem cells provide neurotropic factors and participate in adult neurogenesis. These findings not only shed light on the biology of the disease but also have therapeutic implications in any future stem cell- based clinical trials. PMID:27306906

Mutant Ataxin-1 Inhibits Neural Progenitor Cell Proliferation in SCA1.

PubMed

Cvetanovic, Marija; Hu, Yuan-Shih; Opal, Puneet

2017-04-01

Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by the expansion of a polyglutamine (Q) repeat tract in the protein ataxin-1 (ATXN1). Beginning as a cerebellar ataxic disorder, SCA1 progresses to involve the cerebral cortex, hippocampus, and brainstem. Using SCA1 knock-in mice that mirror the complexity of the human disease, we report a significant decrease in the capacity of adult neuronal progenitor cells (NPCs) to proliferate. Remarkably, a decrease in NPCs proliferation can be observed in vitro, outside the degenerative milieu of surrounding neurons or glia, demonstrating that mutant ATXN1 acting cell autonomously within progenitor cells interferes with their ability to proliferate. Our findings suggest that compromised adult neurogenesis contributes to the progressive pathology of the disease particularly in areas such as the hippocampus and cerebral cortex where stem cells provide neurotropic factors and participate in adult neurogenesis. These findings not only shed light on the biology of the disease but also have therapeutic implications in any future stem cell-based clinical trials.

Deciphering the Combinatorial Roles of Geometric, Mechanical, and Adhesion Cues in Regulation of Cell Spreading

PubMed Central

Harris, Greg M.; Shazly, Tarek; Jabbarzadeh, Ehsan

2013-01-01

Significant effort has gone towards parsing out the effects of surrounding microenvironment on macroscopic behavior of stem cells. Many of the microenvironmental cues, however, are intertwined, and thus, further studies are warranted to identify the intricate interplay among the conflicting downstream signaling pathways that ultimately guide a cell response. In this contribution, by patterning adhesive PEG (polyethylene glycol) hydrogels using Dip Pen Nanolithography (DPN), we demonstrate that substrate elasticity, subcellular elasticity, ligand density, and topography ultimately define mesenchymal stem cells (MSCs) spreading and shape. Physical characteristics are parsed individually with 7 kilopascal (kPa) hydrogel islands leading to smaller, spindle shaped cells and 105 kPa hydrogel islands leading to larger, polygonal cell shapes. In a parallel effort, a finite element model was constructed to characterize and confirm experimental findings and aid as a predictive tool in modeling cell microenvironments. Signaling pathway inhibition studies suggested that RhoA is a key regulator of cell response to the cooperative effect of the tunable substrate variables. These results are significant for the engineering of cell-extra cellular matrix interfaces and ultimately decoupling matrix bound cues presented to cells in a tissue microenvironment for regenerative medicine. PMID:24282570

Derivation and characterization of gut-like structures from embryonic stem cells.

PubMed

Yamada, Takatsugu; Nakajima, Yoshiyuki

2006-01-01

Embryonic stem (ES) cells have a pluripotent ability to differentiate into a variety of cell lineages of all three embryonic germ layers in vitro. The hanging drop culture of ES cell suspension in the absence of leukemia inhibitory factor induces aggregation and differentiation of the cells into simple or cystic embryoid bodies (EBs). After 6 d of hanging drop culture, the resulting EBs are plated onto plastic dishes for the outgrowth culture. At d 21 after outgrowth culture, cell populations of EBs can give rise to three-dimensional gut-like structures that exhibit spontaneous contraction and highly coordinated peristalsis. The gut-like structures have large lumens surrounded by three layers: epithelium, lamina propria, and muscularis. Ganglia are scattered along the periphery, and interstitial cells of Cajal are distributed among the smooth muscle cells. The fundamental process of formation of the in vitro organized gut-like structures is similar to embryonic gastrointestinal development in vivo. The EBs at the 6-d egg-cylinder stage may have the potential to regulate developmental programs associated with cell lineage commitment and provide an appropriate microenvironment to differentiate ES cells into enteric derivatives of all three embryonic germ layers and reproduce the gut organization process in vitro.

Osteoarthritis and stem cell therapy in humans: a systematic review.

PubMed

Jevotovsky, D S; Alfonso, A R; Einhorn, T A; Chiu, E S

2018-06-01

Osteoarthritis (OA) is a leading cause of disability in the world. Mesenchymal stem cells (MSCs) have been studied to treat OA. This review was performed to systematically assess the quality of literature and compare the procedural specifics surrounding MSC therapy for osteoarthritis. PubMed, CINAHL, EMBASE and Cochrane Central Register of Controlled Trials were searched for studies using MSCs for OA treatment (final search December 2017). Outcomes of interest included study evidence level, patient demographics, MSC protocol, treatment results and adverse events. Level I and II evidence articles were further analyzed. Sixty-one of 3,172 articles were identified. These studies treated 2,390 patients with osteoarthritis. Most used adipose-derived stem cells (ADSCs) (n = 29) or bone marrow-derived stem cells (BMSCs) (n = 30) though the preparation varied within group. 57% of the sixty-one studies were level IV evidence, leaving five level I and nine level II studies containing 288 patients to be further analyzed. Eight studies used BMSCs, five ADSCs and one peripheral blood stem cells (PBSCs). The risk of bias in these studies showed five level I studies at low risk with seven level II at moderate and two at high risk. While studies support the notion that MSC therapy has a positive effect on OA patients, there is limited high quality evidence and long-term follow-up. The present study summarizes the specifics of high level evidence studies and identifies a lack of consistency, including a diversity of MSC preparations, and thus a lack of reproducibility amongst these articles' methods. Copyright © 2018 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Engineered Microenvironments for the Maturation and Observation of Human Embryonic Stem Cell Derived Cardiomyocytes

NASA Astrophysics Data System (ADS)

Salick, Max R.

The human heart is a dynamic system that undergoes substantial changes as it develops and adapts to the body's growing needs. To better understand the physiology of the heart, researchers have begun to produce immature heart muscle cells, or cardiomyocytes, from pluripotent stem cell sources with remarkable efficiency. These stem cell-derived cardiomyocytes hold great potential in the understanding and treatment of heart disease; however, even after prolonged culture, these cells continue to exhibit an immature phenotype, as indicated by poor sarcomere organization and calcium handling, among other features. The lack of maturation that is observed in these cardiomyocytes greatly limits their applicability towards drug screening, disease modeling, and cell therapy applications. The mechanical environment surrounding a cell has been repeatedly shown to have a large impact on that cell's behavior. For this reason, we have implemented micropatterning methods to mimic the level of alignment that occurs in the heart in vivo in order to study how this alignment may help the cells to produce a more mature sarcomere phenotype. It was discovered that the level of sarcomere organization of a cardiomyocyte can be strongly influenced by the micropattern lane geometry on which it adheres. Steps were taken to optimize this micropattern platform, and studies of protein organization, gene expression, and myofibrillogenesis were conducted. Additionally, a set of programs was developed to provide quantitative analysis of the level of sarcomere organization, as well as to assist with several other tissue engineering applications.

Alginate Encapsulation of Pluripotent Stem Cells Using a Co-axial Nozzle

PubMed Central

Horiguchi, Ikki; Sakai, Yasuyuki

2015-01-01

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening. However, the development of a mass culture system would be required for using PS cells in these applications. Suspension culture is one promising culture method for the mass production of PS cells, although some issues such as controlling aggregation and limiting shear stress from the culture medium are still unsolved. In order to solve these problems, we developed a method of calcium alginate (Alg-Ca) encapsulation using a co-axial nozzle. This method can control the size of the capsules easily by co-flowing N2 gas. The controllable capsule diameter must be larger than 500 µm because too high a flow rate of N2 gas causes the breakdown of droplets and thus heterogeneous-sized capsules. Moreover, a low concentration of Alg-Na and CaCl2 causes non-spherical capsules. Although an Alg-Ca capsule without a coating of Alg-PLL easily dissolves enabling the collection of cells, they can also potentially leak out from capsules lacking an Alg-PLL coating. Indeed, an alginate-PLL coating can prevent cellular leakage but is also hard to break. This technology can be used to research the stem cell niche as well as the mass production of PS cells because encapsulation can modify the micro-environment surrounding cells including the extracellular matrix and the concentration of secreted factors. PMID:26168084

Cell wars: regulation of cell survival and proliferation by cell competition

PubMed Central

Vivarelli, Silvia; Wagstaff, Laura; Piddini, Eugenia

2012-01-01

During cell competition fitter cells take over the tissue at the expense of viable, but less fit, cells, which are eliminated by induction of apoptosis or senescence. This probably acts as a quality-control mechanism to eliminate suboptimal cells and safeguard organ function. Several experimental conditions have been shown to trigger cell competition, including differential levels in ribosomal activity or in signalling pathway activation between cells, although it is unclear how those differences are sensed and translated into fitness levels. Many of the pathways implicated in cell competition have been previously linked with cancer, and this has led to the hypothesis that cell competition could play a role in tumour formation. Cell competition could be co-opted by cancer cells to kill surrounding normal cells and boost their own tissue colonization. However, in some cases, cell competition could have a tumour suppressor role, as cells harbouring mutations in a subset of tumour suppressor genes are killed by wild-type cells. Originally described in developing epithelia, competitive interactions have also been observed in some stem cell niches, where they play a role in regulating stem cell selection, maintenance and tissue repopulation. Thus competitive interactions could be relevant to the maintenance of tissue fitness and have a protective role against aging. PMID:22928509

S100β-Positive Cells of Mesenchymal Origin Reside in the Anterior Lobe of the Embryonic Pituitary Gland.

PubMed

Horiguchi, Kotaro; Yako, Hideji; Yoshida, Saishu; Fujiwara, Ken; Tsukada, Takehiro; Kanno, Naoko; Ueharu, Hiroki; Nishihara, Hiroto; Kato, Takako; Yashiro, Takashi; Kato, Yukio

2016-01-01

The anterior and intermediate lobes of the pituitary gland develop through invagination of the oral ectoderm and as they are endocrine tissues, they participate in the maintenance of vital functions via the synthesis and secretion of numerous hormones. We recently observed that several extrapituitary cells invade the anterior lobe of the developing pituitary gland. This raised the question of the origin(s) of these S100β-positive cells, which are not classic endocrine cells but instead comprise a heterogeneous cell population with plural roles, especially as stem/progenitor cells. To better understand the roles of these S100β-positive cells, we performed immunohistochemical analysis using several markers in S100β/GFP-TG rats, which express GFP in S100β-expressing cells under control of the S100β promoter. GFP-positive cells were present as mesenchymal cells surrounding the developing pituitary gland and at Atwell's recess but were not present in the anterior lobe on embryonic day 15.5. These cells were negative for SOX2, a pituitary stem/progenitor marker, and PRRX1, a mesenchyme and pituitary stem/progenitor marker. However, three days later, GFP-positive and PRRX1-positive (but SOX2-negative) cells were observed in the parenchyma of the anterior lobe. Furthermore, some GFP-positive cells were positive for vimentin, p75, isolectin B4, DESMIN, and Ki67. These data suggest that S100β-positive cells of extrapituitary origin invade the anterior lobe, undergoing proliferation and diverse transformation during pituitary organogenesis.

S100β-Positive Cells of Mesenchymal Origin Reside in the Anterior Lobe of the Embryonic Pituitary Gland

PubMed Central

Yoshida, Saishu; Fujiwara, Ken; Tsukada, Takehiro; Kanno, Naoko; Ueharu, Hiroki; Nishihara, Hiroto; Kato, Takako; Yashiro, Takashi; Kato, Yukio

2016-01-01

The anterior and intermediate lobes of the pituitary gland develop through invagination of the oral ectoderm and as they are endocrine tissues, they participate in the maintenance of vital functions via the synthesis and secretion of numerous hormones. We recently observed that several extrapituitary cells invade the anterior lobe of the developing pituitary gland. This raised the question of the origin(s) of these S100β-positive cells, which are not classic endocrine cells but instead comprise a heterogeneous cell population with plural roles, especially as stem/progenitor cells. To better understand the roles of these S100β-positive cells, we performed immunohistochemical analysis using several markers in S100β/GFP-TG rats, which express GFP in S100β-expressing cells under control of the S100β promoter. GFP-positive cells were present as mesenchymal cells surrounding the developing pituitary gland and at Atwell's recess but were not present in the anterior lobe on embryonic day 15.5. These cells were negative for SOX2, a pituitary stem/progenitor marker, and PRRX1, a mesenchyme and pituitary stem/progenitor marker. However, three days later, GFP-positive and PRRX1-positive (but SOX2-negative) cells were observed in the parenchyma of the anterior lobe. Furthermore, some GFP-positive cells were positive for vimentin, p75, isolectin B4, DESMIN, and Ki67. These data suggest that S100β-positive cells of extrapituitary origin invade the anterior lobe, undergoing proliferation and diverse transformation during pituitary organogenesis. PMID:27695124

[Effect of different oxygen concentrations on biological properties of bone marrow hematopoietic stem cells of mice].

PubMed

Ma, Yi-Ran; Ren, Si-Hua; He, Yu-Xin; Wang, Lin-Lin; Jin, Li; Hao, Yi-Wen

2012-10-01

This study purposed to investigate the effects of different oxygen concentrations and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and their possible mechanisms through simulating oxygen environment to which the peripheral blood HSC are subjected in peripheral blood HSCT. The proliferation ability, cell cycle, directed differentiation ability, ROS level and hematopoietic reconstitution ability of Lin(-)c-kit(+)Sca-1(+) BMHSC were detected by using in vitro amplification test, directional differentiation test, cell cycle analysis, ROS assay and transplantation of Lin(-)c-kit(+)Sca-1(+) HSC from sublethally irradiated mice respectively. The results showed that oxygen concentrations lower than normal oxygen concentration, especially in hypoxic oxygen environment, could reduce ROS generation and amplify more primitive CD34(+)AC133(+) HSC and active CD34(+) HSC, and maintain more stem cells in the G(0)/G(1) phase, which is more helpful to the growth of CFU-S and viability of mice. At the same time, BMHSC exposed to normal oxygen level or inconstant and greatly changed oxygen concentrations could produce a high level of ROS, and the above-mentioned features and functional indicators are relatively low. It is concluded that ROS levels of HSC in BMHSCT are closely related with the oxygen concentration surrounding the cells and its stability. Low oxygen concentration and antioxidant intervention are helpful to transplantation of BMHSC.

Chymase Cleavage of Stem Cell Factor Yields a Bioactive, Soluble Product

NASA Astrophysics Data System (ADS)

Longley, B. Jack; Tyrrell, Lynda; Ma, Yongsheng; Williams, David A.; Halaban, Ruth; Langley, Keith; Lu, Hsieng S.; Schechter, Norman M.

1997-08-01

Stem cell factor (SCF) is produced by stromal cells as a membrane-bound molecule, which may be proteolytically cleaved at a site close to the membrane to produce a soluble bioactive form. The proteases producing this cleavage are unknown. In this study, we demonstrate that human mast cell chymase, a chymotrypsin-like protease, cleaves SCF at a novel site. Cleavage is at the peptide bond between Phe-158 and Met-159, which are encoded by exon 6 of the SCF gene. This cleavage results in a soluble bioactive product that is 7 amino acids shorter at the C terminus than previously identified soluble SCF. This research shows the identification of a physiologically relevant enzyme that specifically cleaves SCF. Because mast cells express the KIT protein, the receptor for SCF, and respond to SCF by proliferation and degranulation, this observation identifies a possible feedback loop in which chymase released from mast cell secretory granules may solubilize SCF bound to the membrane of surrounding stromal cells. The liberated soluble SCF may in turn stimulate mast cell proliferation and differentiated functions; this loop could contribute to abnormal accumulations of mast cells in the skin and hyperpigmentation at sites of chronic cutaneous inflammation.

In vitro and in vivo biocompatibility study on laser 3D microstructurable polymers

NASA Astrophysics Data System (ADS)

Malinauskas, Mangirdas; Baltriukiene, Daiva; Kraniauskas, Antanas; Danilevicius, Paulius; Jarasiene, Rasa; Sirmenis, Raimondas; Zukauskas, Albertas; Balciunas, Evaldas; Purlys, Vytautas; Gadonas, Roaldas; Bukelskiene, Virginija; Sirvydis, Vytautas; Piskarskas, Algis

2012-09-01

Films and microstructured scaffolds have been fabricated using direct laser writing out of different polymers: hybrid organic-inorganic ORMOCORE b59, acrylate-based AKRE23, novel organic-inorganic Zr containing hybrid SZ2080, and biodegradable PEG-DA-258. Adult myogenic stem cells were grown on these surfaces in vitro. Their adhesion, growth, and viability test results suggest good potential applicability of the materials in biomedical practice. Pieces of these polymers were implanted in rat's paravertebral back tissue. Histological examination of the implants and surrounding tissue ex vivo after 3 weeks of implantation was conducted and results show the materials to be at least as biocompatible as surgical clips or sutures. The applied direct laser writing technique seems to offer good future prospects in a polymeric 3D scaffold design for artificial tissue engineering with autologous stem cells.

Activating Hair Follicle Stem Cells via R-spondin2 to Stimulate Hair Growth.

PubMed

Smith, Andrew A; Li, Jingtao; Liu, Bo; Hunter, Daniel; Pyles, Malcolm; Gillette, Martin; Dhamdhere, Girija R; Abo, Arie; Oro, Anthony; Helms, Jill A

2016-08-01

Wnt signaling is required for the development of the hair follicle, and for inciting the growth (anagen) phase of the hair cycle. Most strategies to enhance Wnt signaling for hair growth create a state of constitutive Wnt activation, which leads to neoplastic transformation of the epithelial hair matrix. Using Axin2(LacZ/+) and Axin2(Cre/+)R26R(mTmG/+) reporter mice and RNA analyses, we show that Wnt signaling is elevated during anagen, is reduced at the onset of catagen, and can be reamplified in the skin and surrounding hair follicles via intradermal injection of recombinant R-spondin2 protein. Using Lgr5(LacZ/+) reporter mice, we demonstrate that this amplified Wnt environment leads to activation of leucine-rich repeat-containing G-protein coupled receptor 5-positive stem cells in the hair follicle. The onset of catagen is repressed by R-spondin2 injection, and the anagen phase persists. As a consequence, hair shafts grow longer. We conclude that R-spondin2 treatment activates hair follicle stem cells and therefore may have therapeutic potential to promote hair growth. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Generating induced pluripotent stem cell derived endothelial cells and induced endothelial cells for cardiovascular disease modelling and therapeutic angiogenesis.

PubMed

Clayton, Z E; Sadeghipour, S; Patel, S

2015-10-15

Standard therapy for atherosclerotic coronary and peripheral arterial disease is insufficient in a significant number of patients because extensive disease often precludes effective revascularization. Stem cell therapy holds promise as a supplementary treatment for these patients, as pre-clinical and clinical research has shown transplanted cells can promote angiogenesis via direct and paracrine mechanisms. Induced pluripotent stem cells (iPSCs) are a novel cell type obtained by reprogramming somatic cells using exogenous transcription factor cocktails, which have been introduced to somatic cells via viral or plasmid constructs, modified mRNA or small molecules. IPSCs are now being used in disease modelling and drug testing and are undergoing their first clinical trial, but despite recent advances, the inefficiency of the reprogramming process remains a major limitation, as does the lack of consensus regarding the optimum transcription factor combination and delivery method and the uncertainty surrounding the genetic and epigenetic stability of iPSCs. IPSCs have been successfully differentiated into vascular endothelial cells (iPSC-ECs) and, more recently, induced endothelial cells (iECs) have also been generated by direct differentiation, which bypasses the pluripotent intermediate. IPSC-ECs and iECs demonstrate endothelial functionality in vitro and have been shown to promote neovessel growth and enhance blood flow recovery in animal models of myocardial infarction and peripheral arterial disease. Challenges remain in optimising the efficiency, safety and fidelity of the reprogramming and endothelial differentiation processes and establishing protocols for large-scale production of clinical-grade, patient-derived cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Testicular receptor 2, Nr2c1, is associated with stem cells in the developing olfactory epithelium and other cranial sensory and skeletal structures.

PubMed

Baker, Jennifer L; Wood, Bernard; Karpinski, Beverly A; LaMantia, Anthony-S; Maynard, Thomas M

2016-01-01

Comparative genomic analysis of the nuclear receptor family suggests that the testicular receptor 2, Nr2c1, undergoes positive selection in the human-chimpanzee clade based upon a significant increase in nonsynonymous compared to synonymous substitutions. Previous in situ analyses of Nr2c1 lacked the temporal range and spatial resolution necessary to characterize cellular expression of this gene from early to mid gestation, when many nuclear receptors are key regulators of tissue specific stem or progenitor cells. Thus, we asked whether Nr2c1 protein is associated with stem cell populations in the mid-gestation mouse embryo. Nr2c1 is robustly expressed in the developing olfactory epithelium. Its expression in the olfactory epithelium shifts from multiple progenitor classes at early stages to primarily transit amplifying cells later in olfactory epithelium development. In the early developing central nervous system, Nr2c1 is limited to the anterior telencephalon/olfactory bulb anlagen, coincident with Nestin-positive neuroepithelial stem cells. Nr2c1 is also seen in additional cranial sensory specializations including cells surrounding the mystacial vibrissae, the retinal pigment epithelium and Scarpa's ganglion. Nr2c1 was also detected in a subset of mesenchymal cells in developing teeth and cranial bones. The timing and distribution of embryonic expression suggests that Nr2c1 is primarily associated with the early genesis of mammalian cranial sensory neurons and craniofacial skeletal structures. Thus, Nr2c1 may be a candidate for mediating parallel adaptive changes in cranial neural sensory specializations such as the olfactory epithelium, retina and mystacial vibrissae and in non-neural craniofacial features including teeth. Copyright © 2015 Elsevier B.V. All rights reserved.

Wnt-Responsive Cancer Stem Cells Are Located Close to Distorted Blood Vessels and Not in Hypoxic Regions in a p53-Null Mouse Model of Human Breast Cancer

PubMed Central

Landua, John D.; Bu, Wen; Wei, Wei; Li, Fuhai; Wong, Stephen T.C.; Dickinson, Mary E.; Rosen, Jeffrey M.; Lewis, Michael T.

2014-01-01

Cancer stem cells (CSCs, or tumor-initiating cells) may be responsible for tumor formation in many types of cancer, including breast cancer. Using high-resolution imaging techniques, we analyzed the relationship between a Wnt-responsive, CSC-enriched population and the tumor vasculature using p53-null mouse mammary tumors transduced with a lentiviral Wnt signaling reporter. Consistent with their localization in the normal mammary gland, Wnt-responsive cells in tumors were enriched in the basal/myoepithelial population and generally located in close proximity to blood vessels. The Wnt-responsive CSCs did not colocalize with the hypoxia-inducible factor 1α-positive cells in these p53-null basal-like tumors. Average vessel diameter and vessel tortuosity were increased in p53-null mouse tumors, as well as in a human tumor xenograft as compared with the normal mammary gland. The combined strategy of monitoring the fluorescently labeled CSCs and vasculature using high-resolution imaging techniques provides a unique opportunity to study the CSC and its surrounding vasculature. PMID:24797826

7 CFR 51.3064 - Damage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... appearance is materially affected; (b) Pulled stems when the exposed stem cavity is excessively deep, or when skin surrounding the stem cavity is more than slightly torn; (c) Russeting or similar discoloration...

7 CFR 51.3064 - Damage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... appearance is materially affected; (b) Pulled stems when the exposed stem cavity is excessively deep, or when skin surrounding the stem cavity is more than slightly torn; (c) Russeting or similar discoloration...

Enhanced osseointegration of titanium implants in a rat model of osteoporosis using multilayer bone mesenchymal stem cell sheets

PubMed Central

Duan, Yan; Ma, Wei; Li, Dehua; Wang, Tongfei; Liu, Baolin

2017-01-01

The present study aimed to investigate whether bone marrow-derived mesenchymal stem cell (BMSC) sheets combined with titanium implants enhanced implant osseointegration in an ovariectomized (OVX) rat model of osteoporosis. Sprague-Dawley rats were randomly assigned into a test group and control group. Allogenic BMSCs were collected from the rats, cultured and stored via cryopreservation. At 6 months post-ovariectomy, establishment of the OVX model was confirmed by micro-computed tomography (CT) measurements. BMSC sheets were subsequently layered and wrapped over titanium implants for implantation. Unmodified implants served as the control. At 8 weeks post-implantation, samples were observed by micro-CT reconstruction and histomorphometric evaluation. Micro-CT reconstruction identified a marked improvement in the surrounding bone volume following treatment, with data analyses indicating a significant increase in bone volume in the BMSC-implant group compared with the control implant group (P<0.05). In addition, histological staining identified new bone formation and an increased rate of bone-implant contact surrounding the BMSC-implant constructs. These results indicate that the use of BMSC sheets as a novel tissue engineering approach improves the osseointegration of titanium implants in an osteoporosis model. This method may expand the operative indications in patients with osteoporosis and improve the success rate of clinical dental implant treatments. PMID:29250137

Early events in xenograft development from the human embryonic stem cell line HS181--resemblance with an initial multiple epiblast formation.

PubMed

Gertow, Karin; Cedervall, Jessica; Jamil, Seema; Ali, Rouknuddin; Imreh, Marta P; Gulyas, Miklos; Sandstedt, Bengt; Ahrlund-Richter, Lars

2011-01-01

Xenografting is widely used for assessing in vivo pluripotency of human stem cell populations. Here, we report on early to late events in the development of mature experimental teratoma from a well-characterized human embryonic stem cell (HESC) line, HS181. The results show an embryonic process, increasingly chaotic. Active proliferation of the stem cell derived cellular progeny was detected already at day 5, and characterized by the appearance of multiple sites of engraftment, with structures of single or pseudostratified columnar epithelium surrounding small cavities. The striking histological resemblance to developing embryonic ectoderm, and the formation of epiblast-like structures was supported by the expression of the markers OCT4, NANOG, SSEA-4 and KLF4, but a lack of REX1. The early neural marker NESTIN was uniformly expressed, while markers linked to gastrulation, such as BMP-4, NODAL or BRACHYURY were not detected. Thus, observations on day 5 indicated differentiation comparable to the most early transient cell populations in human post implantation development. Confirming and expanding on previous findings from HS181 xenografts, these early events were followed by an increasingly chaotic development, incorporated in the formation of a benign teratoma with complex embryonic components. In the mature HS181 teratomas not all types of organs/tissues were detected, indicating a restricted differentiation, and a lack of adequate spatial developmental cues during the further teratoma formation. Uniquely, a kinetic alignment of rare complex structures was made to human embryos at diagnosed gestation stages, showing minor kinetic deviations between HS181 teratoma and the human counterpart.

Stem cell autotomy and niche interaction in different systems

PubMed Central

Dorn, David C; Dorn, August

2015-01-01

The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes (platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells (GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells (homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche (hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion (E-cadherin) and the direction of asymmetrical GSC division - as they were found in Drosophila - can hardly be translated into the systems where GSC autotomy was reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon pruning and dying-back degeneration in neurodegenerative diseases. Especially the hypothesis of an existing evolutionary conserved “autodestruction program” in axons that might also be active in GSC projections appears attractive. Investigations on the underlying signaling pathways have to be carried out. There are two other well known cases of programmed cell autotomy: the enucleation of erythroblasts in the process of erythrocyte maturation and the segregation of thousands of thrombocytes (platelets) from one megakaryocyte. Both progenitor cell types - erythroblasts and megakaryocytes - are associated with a niche in the bone marrow, erythroblasts with a macrophage, which they surround, and the megakaryocytes with the endothelial cells of sinusoids and their extracellular matrix. Although the regulatory mechanisms may be specific in each case, there is one aspect that connects all described processes of programmed cell autotomy and neuronal autodestruction: apoptotic pathways play always a prominent role. Studies on the role of male GSC autotomy in stem cell-niche interaction have just started but are expected to reveal hitherto unknown ways of signal exchange. Spermatogenesis in mammals advance our understanding of insect spermatogenesis. Mammal and insect spermatogenesis share some broad principles, but a comparison of the signaling pathways is difficult. We have intimate knowledge from Drosophila, but of almost no other insect, and we have only limited knowledge from mammals. The discovery of stem cell autotomy as part of the interaction with the niche promises new general insights into the complicated stem cell-niche interdependence. PMID:26240680

Human Herpesvirus-6 cytopathic inclusions: an exceptional and recognizable finding on skin biopsy during HHV6 reactivation after autologous stem-cell transplantation.

PubMed

Roux, Jennifer; Battistella, Maxime; Fornecker, Luc; Legoff, Jérôme; Deau, Bénédicte; Houhou, Nadira; Bouaziz, Jean-David; Thieblemont, Catherine; Janin, Anne

2012-08-01

Skin rash are common in immunocompromised patients, particularly after bone marrow transplantation. Human herpes virus 6 (HHV6) reactivation is often suspected, but its clinical presentation and the routine laboratory tests may be unspecific, thus leading to late diagnosis. In this case, we report specific intralymphocytic cytopathic inclusions on skin biopsy as a sign of systemic HHV6 reactivation. A 56-year-old patient presented progressive erythroderma and fever occurring after autologous hematopoietic stem-cell transplantation for mantle cell lymphoma. The skin biopsy showed a perivascular infiltrate of medium-to-large lymphocytes with irregular nuclei containing a large central basophilic inclusion surrounded by a clear halo. High levels of HHV-6 genomic in skin biopsy confirm HHV-6-induced cytopathic effect. The clinical course improved with intravenous foscavir. The specific histopathological findings encountered in this case are exceptional but recognizable, and along with HHV-6 DNA detection allow a prompt recognition of HHV6 skin rash.

Exosomes released by chronic lymphocytic leukemia cells induce the transition of stromal cells into cancer-associated fibroblasts

PubMed Central

Paggetti, Jerome; Haderk, Franziska; Seiffert, Martina; Janji, Bassam; Distler, Ute; Ammerlaan, Wim; Kim, Yeoun Jin; Adam, Julien; Lichter, Peter; Solary, Eric; Berchem, Guy

2015-01-01

Exosomes derived from solid tumor cells are involved in immune suppression, angiogenesis, and metastasis, but the role of leukemia-derived exosomes has been less investigated. The pathogenesis of chronic lymphocytic leukemia (CLL) is stringently associated with a tumor-supportive microenvironment and a dysfunctional immune system. Here, we explore the role of CLL-derived exosomes in the cellular and molecular mechanisms by which malignant cells create this favorable surrounding. We show that CLL-derived exosomes are actively incorporated by endothelial and mesenchymal stem cells ex vivo and in vivo and that the transfer of exosomal protein and microRNA induces an inflammatory phenotype in the target cells, which resembles the phenotype of cancer-associated fibroblasts (CAFs). As a result, stromal cells show enhanced proliferation, migration, and secretion of inflammatory cytokines, contributing to a tumor-supportive microenvironment. Exosome uptake by endothelial cells increased angiogenesis ex vivo and in vivo, and coinjection of CLL-derived exosomes and CLL cells promoted tumor growth in immunodeficient mice. Finally, we detected α-smooth actin–positive stromal cells in lymph nodes of CLL patients. These findings demonstrate that CLL-derived exosomes actively promote disease progression by modulating several functions of surrounding stromal cells that acquire features of cancer-associated fibroblasts. PMID:26100252

Preclinical evaluation of the immunomodulatory properties of cardiac adipose tissue progenitor cells using umbilical cord blood mesenchymal stem cells: a direct comparative study.

PubMed

Perea-Gil, Isaac; Monguió-Tortajada, Marta; Gálvez-Montón, Carolina; Bayes-Genis, Antoni; Borràs, Francesc E; Roura, Santiago

2015-01-01

Cell-based strategies to regenerate injured myocardial tissue have emerged over the past decade, but the optimum cell type is still under scrutiny. In this context, human adult epicardial fat surrounding the heart has been characterized as a reservoir of mesenchymal-like progenitor cells (cardiac ATDPCs) with potential clinical benefits. However, additional data on the possibility that these cells could trigger a deleterious immune response following implantation are needed. Thus, in the presented study, we took advantage of the well-established low immunogenicity of umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) to comparatively assess the immunomodulatory properties of cardiac ATDPCs in an in vitro allostimulatory assay using allogeneic mature monocyte-derived dendritic cells (MDDCs). Similar to UCBMSCs, increasing amounts of seeded cardiac ATDPCs suppressed the alloproliferation of T cells in a dose-dependent manner. Secretion of proinflammatory cytokines (IL6, TNFα, and IFNγ) was also specifically modulated by the different numbers of cardiac ATDPCs cocultured. In summary, we show that cardiac ATDPCs abrogate T cell alloproliferation upon stimulation with allogeneic mature MDDCs, suggesting that they could further regulate a possible harmful immune response in vivo. Additionally, UCBMSCs can be considered as valuable tools to preclinically predict the immunogenicity of prospective regenerative cells.

Nanoparticle-neural stem cells for targeted ovarian cancer treatment: optimization of silica nanoparticles for efficient drug loading

NASA Astrophysics Data System (ADS)

Patel, Z.; Berlin, J.; Abidi, W.

2018-02-01

One of the drugs used to treat ovarian cancer is cisplatin. However, cisplatin kills normal surrounding tissue in addition to cancer cells. To improve tumor targeting efficiency, our lab uses neural stem cells (NSCs), which migrate directly to ovarian tumors. If free cisplatin is loaded into NSCs for targeted drug delivery, it will kill the NSCs. To prevent the drug cisplatin from killing both the NSCs and normal surrounding tissue, our lab synthesizes silica nanoparticles (SiNPs) that act as a protective carrier. The big picture here is to maximize efficiency of tumor targeting using NSCs and minimize toxicity to these NSCs using SiNPs. The goal of this project is to optimize the stability of SiNPs, which is important for efficient drug loading. To do this, the concentration of tetraethyl orthosilicate (TEOS), one of the main components of SiNPs, was varied. We hypothesized that more TEOS equates to more stable SiNPs because TEOS contributes carbon to SiNPs, and thus a tightly-packed chemical structure results in a stable particle. Then, the stability of the SiNPs were checked in cell media and phosphate buffered saline (PBS). Lastly, the SiNPs were analyzed for their porosity using the transmission electron microscope (TEM). TEM imaging showed white spots in the 200-800 μL TEOS batches and no white spots in the 1000-1800 μL TEOS batches. The white spots were pores, which indicate instability. We concluded that the ultimate factor that determines the stability of SiNPs (100 nm) is the concentration of organic substance.

An empirical method that separates irreversible stem radial growth from bark water content changes in trees: theory and case studies.

PubMed

Mencuccini, Maurizio; Salmon, Yann; Mitchell, Patrick; Hölttä, Teemu; Choat, Brendan; Meir, Patrick; O'Grady, Anthony; Tissue, David; Zweifel, Roman; Sevanto, Sanna; Pfautsch, Sebastian

2017-02-01

Substantial uncertainty surrounds our knowledge of tree stem growth, with some of the most basic questions, such as when stem radial growth occurs through the daily cycle, still unanswered. We employed high-resolution point dendrometers, sap flow sensors, and developed theory and statistical approaches, to devise a novel method separating irreversible radial growth from elastic tension-driven and elastic osmotically driven changes in bark water content. We tested this method using data from five case study species. Experimental manipulations, namely a field irrigation experiment on Scots pine and a stem girdling experiment on red forest gum trees, were used to validate the theory. Time courses of stem radial growth following irrigation and stem girdling were consistent with a-priori predictions. Patterns of stem radial growth varied across case studies, with growth occurring during the day and/or night, consistent with the available literature. Importantly, our approach provides a valuable alternative to existing methods, as it can be approximated by a simple empirical interpolation routine that derives irreversible radial growth using standard regression techniques. Our novel method provides an improved understanding of the relative source-sink carbon dynamics of tree stems at a sub-daily time scale. © 2016 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Two-Step Functional Innovation of the Stem-Cell Factors WUS/WOX5 during Plant Evolution.

PubMed

Zhang, Yuzhou; Jiao, Yue; Jiao, Hengwu; Zhao, Huabin; Zhu, Yu-Xian

2017-03-01

WUS and WOX5, which are expressed, respectively, in the organizing center (OC) and the quiescent center (QC), are essential for shoot/root apical stem-cell maintenance in flowering plants. However, little is known about how these stem-cell factors evolved their functions in flowering plants. Here, we show that the WUS/WOX5 proteins acquired two distinct capabilities by a two-step functional innovation process in the course of plant evolution. The first-step is the apical stem-cell maintenance activity of WUS/WOX5, which originated in the common ancestor of ferns and seed plants, as evidenced by the interspecies complementation experiments, showing that ectopic expression of fern Ceratopteris richardii WUS-like (CrWUL) surrounding OC/QC, or exclusive OC-/QC-expressed gymnosperms/angiosperms WUS/WOX5 in Arabidopsis wus-1 and wox5-1 mutants, could rescue their phenotypes. The second-step is the intercellular mobility that emerged in the common ancestor of seed plants after divergence from the ferns. Evidence for this includes confocal imaging of GFP fusion proteins, showing that WUS/WOX5 from seed plants, rather than from the fern CrWUL, can migrate into cells adjacent to the OC/QC. Evolutionary analysis showed that the WUS-like gene was duplicated into two copies prior to the divergence of gymnosperms/angiosperms. Then the two gene copies (WUS and WOX5) have undergone similar levels of purifying selection, which is consistent with their conserved functions in angiosperm shoot/root stem-cell maintenance and floral organ formation. Our results highlight the critical roles and the essential prerequisites that the two-step functional innovation of these genes performs and represents in the origin of flowering plants. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Inhibition of AQP1 Hampers Osteosarcoma and Hepatocellular Carcinoma Progression Mediated by Bone Marrow-Derived Mesenchymal Stem Cells.

PubMed

Pelagalli, Alessandra; Nardelli, Anna; Fontanella, Raffaela; Zannetti, Antonella

2016-07-11

The complex cross-talk between tumor cells and their surrounding stromal environment plays a key role in the pathogenesis of cancer. Among several cell types that constitute the tumor stroma, bone marrow-derived mesenchymal stem cells (BM-MSCs) selectively migrate toward the tumor microenvironment and contribute to the active formation of tumor-associated stroma. Therefore, here we elucidate the involvement of BM-MSCs to promote osteosarcoma (OS) and hepatocellular carcinoma (HCC) cells migration and invasion and deepening the role of specific pathways. We analyzed the function of aquaporin 1 (AQP1), a water channel known to promote metastasis and neoangiogenes. AQP1 protein levels were analyzed in OS (U2OS) and HCC (SNU-398) cells exposed to conditioned medium from BM-MSCs. Tumor cell migration and invasion in response to BM-MSC conditioned medium were evaluated through a wound healing assay and Boyden chamber, respectively. The results showed that the AQP1 level was increased in both tumor cell lines after treatment with BM-MSC conditioned medium. Moreover, BM-MSCs-mediated tumor cell migration and invasion were hampered after treatment with AQP1 inhibitor. These data suggest that the recruitment of human BM-MSCs into the tumor microenvironment might cause OS and HCC cell migration and invasion through involvement of AQP1.

Development and Translation of a Tissue-Engineered Disc in a Preclinical Rodent Model

DTIC Science & Technology

2014-12-01

annulus fibrosus tissue into full 3D Disc-like Angle Ply Structures (DAPS), inclusive of a hyaluronic acid hydrogel seeded with adult stem cells, that...AF constructs surrounding an engineered nucleus pulposus (NP) composed of a hyaluronic acid (HA) hydrogel. Measure the disc structural mechanics in...exposure to TGF-ß3 improves the functional properties of MSC-seeded photocrosslinked hyaluronic acid hydrogels by authors Minwook Kim, Isaac E

The effects of dynamic loading on the intervertebral disc.

PubMed

Chan, Samantha C W; Ferguson, Stephen J; Gantenbein-Ritter, Benjamin

2011-11-01

Loading is important to maintain the balance of matrix turnover in the intervertebral disc (IVD). Daily cyclic diurnal assists in the transport of large soluble factors across the IVD and its surrounding circulation and applies direct and indirect stimulus to disc cells. Acute mechanical injury and accumulated overloading, however, could induce disc degeneration. Recently, there is more information available on how cyclic loading, especially axial compression and hydrostatic pressure, affects IVD cell biology. This review summarises recent studies on the response of the IVD and stem cells to applied cyclic compression and hydrostatic pressure. These studies investigate the possible role of loading in the initiation and progression of disc degeneration as well as quantifying a physiological loading condition for the study of disc degeneration biological therapy. Subsequently, a possible physiological/beneficial loading range is proposed. This physiological/beneficial loading could provide insight into how to design loading regimes in specific system for the testing of various biological therapies such as cell therapy, chemical therapy or tissue engineering constructs to achieve a better final outcome. In addition, the parameter space of 'physiological' loading may also be an important factor for the differentiation of stem cells towards most ideally 'discogenic' cells for tissue engineering purpose.

Emulating Native Periosteum Cell Population and Subsequent Paracrine Factor Production To Promote Tissue Engineered Periosteum-Mediated Allograft Healing

PubMed Central

Hoffman, Michael D.

2015-01-01

Emulating autograft healing within the context of decellularized bone allografts has immediate clinical applications in the treatment of critical-sized bone defects. The periosteum, a thin, osteogenic tissue that surrounds bone, houses a heterogeneous population of stem cells and osteoprogenitors. There is evidence that periosteum-cell derived paracrine factors, specifically vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP2), orchestrate autograft healing through host cell recruitment and subsequent tissue elaboration. In previous work, we demonstrated that the use of poly(ethylene glycol) (PEG) hydrogels as a tissue engineered (T.E.) periosteum to localize mesenchymal stem cells (MSCs) to the surface of decellularized bone enhances allograft healing and integration. Herein, we utilize a mixed population of 50:50 MSCs and osteoprogenitor cells to better mimic native periosteum cell population and paracrine factor production to further promote allograft healing. This mixed cell population was localized to the surface of decellularized allografts within degradable hydrogels and shown to expedite allograft healing. Specifically, bone callus formation and biomechanical graft-host integration are increased as compared to unmodified allografts. These results demonstrate the dual importance of periosteum-mediated paracrine factors orchestrating host cell recruitment as well as new bone formation while developing clinically translatable strategies for allograft healing and integration. PMID:25818449

Cell and matrix modulation in prenatal and postnatal equine growth cartilage, zones of Ranvier and articular cartilage

PubMed Central

Löfgren, Maria; Ekman, Stina; Svala, Emilia; Lindahl, Anders; Ley, Cecilia; Skiöldebrand, Eva

2014-01-01

Formation of synovial joints includes phenotypic changes of the chondrocytes and the organisation of their extracellular matrix is regulated by different factors and signalling pathways. Increased knowledge of the normal processes involved in joint development may be used to identify similar regulatory mechanisms during pathological conditions in the joint. Samples of the distal radius were collected from prenatal and postnatal equine growth plates, zones of Ranvier and articular cartilage with the aim of identifying Notch signalling components and cells with stem cell-like characteristics and to follow changes in matrix protein localisation during joint development. The localisation of the Notch signalling components Notch1, Delta4, Hes1, Notch dysregulating protein epidermal growth factor-like domain 7 (EGFL7), the stem cell-indicating factor Stro-1 and the matrix molecules cartilage oligomeric matrix protein (COMP), fibromodulin, matrilin-1 and chondroadherin were studied using immunohistochemistry. Spatial changes in protein localisations during cartilage maturation were observed for Notch signalling components and matrix molecules, with increased pericellular localisation indicating new synthesis and involvement of these proteins in the formation of the joint. However, it was not possible to characterise the phenotype of the chondrocytes based on their surrounding matrix during normal chondrogenesis. The zone of Ranvier was identified in all horses and characterised as an area expressing Stro-1, EGFL7 and chondroadherin with an absence of COMP and Notch signalling. Stro-1 was also present in cells close to the perichondrium, in the articular cartilage and in the fetal resting zone, indicating stem cell-like characteristics of these cells. The presence of stem cells in the articular cartilage will be of importance for the repair of damaged cartilage. Perivascular chondrocytes and hypertrophic cells of the cartilage bone interface displayed positive staining for EGFL7, which is a novel finding and suggests a role of EGFL7 in the vascular infiltration of growth cartilage. PMID:25175365

Rotatable stem and lock

DOEpatents

Deveney, Joseph E.; Sanderson, Stephen N.

1984-01-01

A valve stem and lock include a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

Rotatable stem and lock

DOEpatents

Deveney, J.E.; Sanderson, S.N.

1981-10-27

A valve stem and lock is disclosed which includes a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

Functional properties of cells obtained from human cord blood CD34+ stem cells and mouse cardiac myocytes in coculture.

PubMed

Orlandi, Alessia; Pagani, Francesca; Avitabile, Daniele; Bonanno, Giuseppina; Scambia, Giovanni; Vigna, Elisa; Grassi, Francesca; Eusebi, Fabrizio; Fucile, Sergio; Pesce, Maurizio; Capogrossi, Maurizio C

2008-04-01

Prior in vitro studies suggested that different types of hematopoietic stem cells may differentiate into cardiomyocytes. The present work examined whether human CD34(+) cells from the human umbilical cord blood (hUCB), cocultured with neonatal mouse cardiomyocytes, acquire the functional properties of myocardial cells and express human cardiac genes. hUCB CD34(+) cells were cocultured onto cardiomyocytes following an infection with a lentivirus-encoding enhanced green fluorescent protein (EGFP). After 7 days, mononucleated EGFP(+) cells were tested for their electrophysiological features by patch clamp and for cytosolic [Ca(2+)] ([Ca(2+)](i)) homeostasis by [Ca(2+)](i) imaging of X-rhod1-loaded cells. Human Nkx2.5 and GATA-4 expression was examined in cocultured cell populations by real-time RT-PCR. EGFP(+) cells were connected to surrounding cells by gap junctions, acquired electrophysiological properties similar to those of cardiomyocytes, and showed action potential-associated [Ca(2+)](i) transients. These cells also exhibited spontaneous sarcoplasmic reticulum [Ca(2+)](i) oscillations and the associated membrane potential depolarization. However, RT-PCR of both cell populations showed no upregulation of human-specific cardiac genes. In conclusion, under our experimental conditions, hUCB CD34(+) cells cocultured with murine cardiomyocytes formed cells that exhibited excitation-contraction coupling features similar to those of cardiomyocytes. However, the expression of human-specific cardiac genes was undetectable by RT-PCR.

SDF-1 promotes endochondral bone repair during fracture healing at the traumatic brain injury condition.

PubMed

Liu, Xiaoqi; Zhou, Changlong; Li, Yanjing; Ji, Ye; Xu, Gongping; Wang, Xintao; Yan, Jinglong

2013-01-01

The objective of this study was to investigate the role of stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, on bone healing and whether SDF-1 contributes to accelerating bone repair in traumatic brain injury (TBI)/fracture model. Real-time polymerase chain reaction and immunohistochemical analysis were used to detect the expression of SDF-1 during the repair of femoral bone in TBI/fracture model. The TBI/fracture model was treated with anti-SDF-1 neutralizing antibody or AMD3100, an antagonist for CXCR4, and evaluated by histomorphometry. In vitro and in vivo migration assays were used to evaluate the functional effect of SDF-1 on primary mesenchymal stem cells. The expression of SDF1 and CXCR4 messenger RNA was increased during the bone healing in TBI/fracture model but was less increased in fracture only model. High expression of SDF-1 protein was observed in the surrounding tissue of the damaged bone. Treated with anti-SDF-1 antibody or AMD3100 could inhibit new bone formation. SDF-1 increased mesenchymal stem cell chemotaxis in vitro in a dose-dependent manner. The in vivo migration study demonstrated that mesenchymal stem cells recruited by SDF-1 participate in endochondral bone repair. The SDF-1/CXCR4 axis plays a crucial role in the accelerating fracture healing under the condition of TBI and contributes to endochondral bone repair.

CB-02MiRNA EXPRESSION PROFILES OF GLIOMA STEM CELLS AND THEIR ASSOCIATION WITH THE MESENCHYMAL TRANSFORMATION OF THESE CELLS

PubMed Central

Bier, Ariel; Finniss, Susan; Cazacu, Simona; Xiang, Cunli; Lee, Hae Kyung; Rand, Daniel; Yalon, Michal; Toren, Amos; Poisson, Laila; Brodie, Chaya

2014-01-01

Glioblastoma, are characterized by increased infiltration into the surrounding brain tissue, resistance to therapies, and poor prognosis. A major pathway that contributes to these characteristics is the mesenchymal phenotype of these tumors. A small subpopulation of cancer stem cells (GSCs) have been implicated in the enhanced infiltration, radio-resistance and tumor recurrence. GSCs share some similarities with neural stem cells (NSCs) but exhibit deregulated differentiation ability and enhanced oncogenic potential. Recent studies documented miRNAs as important regulators of GSC functions and of the malignant and stemness features of these cells. In this study we performed miRNA and mRNA integrated analysis of GSCs compared to human NSCs and mesenchymal stromal cells (MSCs) to identify significant miRNA-mRNA signatures associated with the mesenchymal signature of GSCs, using miRNA and mRNA microarray analysis. The comparison of GSCs and NSCs identified 79 miRNAs that were upregulated in GSCs and 21 miRNAs that were increased in MSCs. Twenty six miRNAs were downregulated in GSCs compared to NSCs and 21 miRNAs from this group were further downregulated in MSCs. The comparison of mRNA expression of GSCs and NSCs identified gene clusters associated with glioma cell invasiveness, axonal guidance signaling and TGF-b signaling. miR-504 is one of the miRNAs that was significantly downregulated in GSCs compared to NSCs. The expression of miR-504 was also decreased in mesenchymal GBM and highly increased in the G-CIMP subset of GBM. miR-504 promoted the neural differentiation of GSC, inhibited their self-renewal, migration and the mesenchymal signature of these cells, by downregulating CD44, BCAN, ZRB1 and ZEB2. In conclusion, these results reveal novel miRNAs and potential target networks that play a role in the oncogenic potential and stemness of GSCs and in their mesenchymal transformation and may lead to the identification of therapeutic targets for the eradication of GSCs and the treatment of GBM.

Bone marrow mesenchymal stem cells accelerate the hyperglycemic refractory wound healing by inhibiting an excessive inflammatory response.

PubMed

Nan, Wenbin; Xu, Zhihao; Chen, Zhibin; Yuan, Xin; Lin, Juntang; Feng, Huigen; Lian, Jie; Chen, Hongli

2017-05-01

The aim of the present study was to evaluate the healing effect of bone marrow-derived mesenchymal stem cells administered to hyperglycemia model mice with skin wounds, and to explore the underlying mechanism contributing to their effects in promoting refractory wound healing. A full‑thickness skin wound mouse model was established, and refers to a wound of the skin and subcutaneous tissue. The mice were randomly divided into three groups: Blank control group, hyperglycemic group and a hyperglycemic group treated with stem cells. Wound healing was monitored and the wound‑healing rate was determined at 3, 6, 9, and 12 days following trauma. The structure of the organization of new skin tissue was observed by hematoxylin and eosin staining, and expression levels of the inflammatory cytokines interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α were determined from 1 to 6 days following trauma. The wound healing of the hyperglycemic group was slower than that of the blank group, and the hyperglycemic mice treated with stem cells presented faster healing than the hyperglycemia group. The horny layer and granular layer of the skin were thinner and incomplete in the new skin tissue of the hyperglycemic group, whereas the new skin wound tissue basal layer was flat and demonstrated better fusion with the wound edge in the other two groups. The expression of inflammatory cytokines (IL‑6 and TNF‑α) was significantly increased in all three groups, with continuously higher expression in the hyperglycemic group and decreased expression in the other two groups over time. Hyperglycemia refractory wounds are likely related to the excessive expression of inflammatory cytokines surrounding the wound area. Stem cells may be able to alleviate the excessive inflammatory reaction in the wound tissue of hyperglycemic mice, so as to promote wound healing.

Müller glia: Stem cells for generation and regeneration of retinal neurons in teleost fish

PubMed Central

Lenkowski, Jenny R.; Raymond, Pamela A.

2014-01-01

Adult zebrafish generate new neurons in the brain and retina throughout life. Growth-related neurogenesis allows a vigorous regenerative response to damage, and fish can regenerate retinal neurons, including photoreceptors, and restore functional vision following photic, chemical, or mechanical destruction of the retina. Müller glial cells in fish function as radial-glial-like neural stem cells. During adult growth, Müller glial nuclei undergo sporadic, asymmetric, self-renewing mitotic divisions in the inner nuclear layer to generate a rod progenitor that migrates along the radial fiber of the Müller glia into the outer nuclear layer, proliferates, and differentiates exclusively into rod photoreceptors. When retinal neurons are destroyed, Müller glia in the immediate vicinity of the damage partially and transiently dedifferentiate, re-express retinal progenitor and stem cell markers, re-enter the cell cycle, undergo interkinetic nuclear migration (characteristic of neuroepithelial cells), and divide once in an asymmetric, self-renewing division to generate a retinal progenitor. This daughter cell proliferates rapidly to form a compact neurogenic cluster surrounding the Müller glia; these multipotent retinal progenitors then migrate along the radial fiber to the appropriate lamina to replace missing retinal neurons. Some aspects of the injury-response in fish Müller glia resemble gliosis as observed in mammals, and mammalian Müller glia exhibit some neurogenic properties, indicative of a latent ability to regenerate retinal neurons. Understanding the specific properties of fish Müller glia that facilitate their robust capacity to generate retinal neurons will inform and inspire new clinical approaches for treating blindness and visual loss with regenerative medicine. PMID:24412518

EMPOWERING ADULT STEM CELLS FOR MYOCARDIAL REGENERATION

PubMed Central

Mohsin, Sadia; Siddiqi, Sailay; Collins, Brett; Sussman, Mark A.

2012-01-01

Treatment strategies for heart failure remain a high priority for ongoing research due to the profound unmet need in clinical disease coupled with lack of significant translational progress. The underlying issue is the same whether the cause is acute damage, chronic stress from disease, or aging: progressive loss of functional cardiomyocytes and diminished hemodynamic output. To stave off cardiomyocyte losses, a number of strategic approaches have been embraced in recent years involving both molecular and cellular approaches to augment myocardial structure and performance. Resultant excitement surrounding regenerative medicine in the heart has been tempered by realizations that reparative processes in the heart are insufficient to restore damaged myocardium to normal functional capacity and that cellular cardiomyoplasty is hampered by poor survival, proliferation, engraftment and differentiation of the donated population. To overcome these limitations, a combination of molecular and cellular approaches needs to be adopted involving use of genetic engineering to enhance resistance to cell death and increase regenerative capacity. This review will highlight biological properties of approached to potentiate stem cell-mediated regeneration to promote enhanced myocardial regeneration, persistence of donated cells, and long lasting tissue repair. Optimizing cell delivery and harnessing the power of survival signaling cascades for ex vivo genetic modification of stem cells prior to reintroduction into the patient will be critical to enhance the efficacy of cellular cardiomyoplasty. Once this goal is achieved, then cell-based therapy has great promise for treatment of heart failure to combat the loss of cardiac structure and function associated with acute damage, chronic disease or aging. PMID:22158649

Porphyromonas gingivalis can invade periodontal ligament stem cells.

PubMed

Pan, Chunling; Liu, Junchao; Wang, Hongyan; Song, Jia; Tan, Lisi; Zhao, Haijiao

2017-02-17

Porphyromonas gingivalis is strongly associated with the development, progression, severity and recurrence of periodontitis. Periodontal ligament stem cells (PDLSCs) play an important role in the maintenance of periodontal tissue self-renewal and repair. The purpose of this study was to investigate the ability of P. gingivalis to infect PDLSCs using an in vitro monolayer model. We separated and cultured primary PDLSCs using the tissue block with limiting dilution method. The efficiency of P. gingivalis (ATCC 33277) infection of PDLSCs was measured using agar plate culture and quantitative polymerase chain reaction (q-PCR) methods. PDLSCs infected with P. gingivalis were also observed by transmission electron microscopy. We assessed stem cell properties including cell morphology, clone formation, growth activity, cell surface antigens and multiple differentiation capacity. The infection rates of P. gingivalis in PDLSC at MOIs of 50, 100, 200, and 500 were 5.83%, 8.12%, 7.77% and 7.53% according to the agar plate culture method. By q-PCR, the efficiencies of P. gingivalis infection of PDLSCs at MOIs of 50, 100, 200, and 500 were 6.74%, 10.56%, 10.36% and 9.78%, respectively. Overall, the infection efficiency based on q-PCR was higher than that according to agar plate culture. Using transmission electron microscopy, we verified that P. gingivalis (ATCC 33277) could infect and invade PDLSCs after 2 h of incubation, and endocytic vacuoles were not found surrounding the internalized bacteria. In conclusion, our data demonstrate that P. gingivalis can invade PDLSCs.

Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

NASA Astrophysics Data System (ADS)

Zhang, Lingli; Hanagata, Nobutaka; Maeda, Megumi; Minowa, Takashi; Ikoma, Toshiyuki; Fan, Hongsong; Zhang, Xingdong

2009-04-01

Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in β-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than β-TCP.

Surgical Ablation Assay for Studying Eye Regeneration in Planarians.

PubMed

Morton, Jacob M; Saad, Marwa A; Beane, Wendy S

2017-04-14

In the study of adult stem cells and regenerative mechanisms, planarian flatworms are a staple in vivo model system. This is due in large part to their abundant pluripotent stem cell population and ability to regenerate all cell and tissue types after injuries that would be catastrophic for most animals. Recently, planarians have gained popularity as a model for eye regeneration. Their ability to regenerate the entire eye (comprised of two tissue types: pigment cells and photoreceptors) allows for the dissection of the mechanisms regulating visual system regeneration. Eye ablation has several advantages over other techniques (such as decapitation or hole punch) for examining eye-specific pathways and mechanisms, the most important of which is that regeneration is largely restricted to eye tissues alone. The purpose of this video article is to demonstrate how to reliably remove the planarian optic cup without disturbing the brain or surrounding tissues. The handling of worms and maintenance of an established colony is also described. This technique uses a 31 G, 5/16-inch insulin needle to surgically scoop out the optic cup of planarians immobilized on a cold plate. This method encompasses both single and double eye ablation, with eyes regenerating within 1-2 weeks, allowing for a wide range of applications. In particular, this ablation technique can be easily combined with pharmacological and genetic (RNA interference) screens for a better understanding of regenerative mechanisms and their evolution, eye stem cells and their maintenance, and phototaxic behavioral responses and their neurological basis.

Influences of photosynthetically active radiation on cladode orientation, stem tilting, and height of cacti

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobel, P.S.

1981-08-01

Stem orientation and morphology were investigated for 14 species of cacti in Chile, Ecuador, Mexico, and the United States. The interception of photosynthetically active radiation (PAR) was specifically considered for cladodes (flattened stems) of platyopuntias, for tilted cylindrical stems, and in the presence of surrounding vegetation.

Targeting Epithelial-Mesenchymal Transition (EMT) to Overcome Drug Resistance in Cancer.

PubMed

Du, Bowen; Shim, Joong Sup

2016-07-22

Epithelial-mesenchymal transition (EMT) is known to play an important role in cancer progression, metastasis and drug resistance. Although there are controversies surrounding the causal relationship between EMT and cancer metastasis, the role of EMT in cancer drug resistance has been increasingly recognized. Numerous EMT-related signaling pathways are involved in drug resistance in cancer cells. Cells undergoing EMT show a feature similar to cancer stem cells (CSCs), such as an increase in drug efflux pumps and anti-apoptotic effects. Therefore, targeting EMT has been considered a novel opportunity to overcome cancer drug resistance. This review describes the mechanism by which EMT contributes to drug resistance in cancer cells and summarizes new advances in research in EMT-associated drug resistance.

Biology of Bone: The Vasculature of the Skeletal System.

PubMed

Watson, Emma C; Adams, Ralf H

2017-09-11

Blood vessels are essential for the distribution of oxygen, nutrients, and immune cells, as well as the removal of waste products. In addition to this conventional role as a versatile conduit system, the endothelial cells forming the innermost layer of the vessel wall also possess important signaling capabilities and can control growth, patterning, homeostasis, and regeneration of the surrounding organ. In the skeletal system, blood vessels regulate developmental and regenerative bone formation as well as hematopoiesis by providing vascular niches for hematopoietic stem cells. Here we provide an overview of blood vessel architecture, growth and properties in the healthy, aging, and diseased skeletal system. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

Controlling micro- and nano-environment of tumor and stem cells for novel research and therapy of brain cancer

NASA Astrophysics Data System (ADS)

Smith, Christopher Lloyd

The use of modern technologies in cancer research has engendered a great deal of excitement. Many of these advanced approaches involve in-depth mathematical analyses of the inner working of cells, via genomic and proteomic analyses. However these techniques may not be ideal for the study of complex cell phenotypes and behaviors. This dissertation explores cancer and potential therapies through phenotypic analysis of cell behaviors, an alternative approach. We employ this experimental framework to study brain cancer (glioma), a particularly formidable example of this diverse ailment. Through the application of micro- and nanotechnology, we carefully control the surrounding environments of cells to understand their responses to various cues and to manipulate their behaviors. Subsequently we obtain clinically relevant information that allows better understanding of glioma, and enhancement of potential therapies. We first aim to address brain tumor dispersal, through analysis of cell migration. Utilizing nanometer-scale topographic models of the extracellular matrix, we study the migratory response of glioma cells to various stimuli in vitro. Second, we implement knowledge gained from these investigations to define characteristics of tumor progression in patients, and to develop treatments inhibiting cell migration. Next we use microfluidic and nanotopographic models to study the behaviors of stem cells in vitro. Here we attempt to improve their abilities to deliver therapeutic proteins to cancer, an innovative treatment approach. We analyze the multi-step process by which adipose-derived stem cells naturally home to tumor sites, and identify numerous environmental perturbations to enhance this behavior. Finally, we attempt to demonstrate that these cell culture-based manipulations can enhance the localization of adipose stem cells to glioma in vivo using animal models. Throughout this work we utilize environmental cues to analyze and induce particular behaviors in cells. We further demonstrate that this general technique can be used to determine clinically relevant tumor characteristics, to identify potential drug targets, and to enhance potential therapies. Therefore this thesis illuminates a novel framework for experimentation into cancer, and specifically advances two treatment approaches. We anticipate that the methodologies described in this study will prove useful to various branches of medicine and biological research.

Body Management: Mesenchymal Stem Cells Control the Internal Regenerator

PubMed Central

Hariri, Robert

2015-01-01

Summary It has been assumed that adult tissues cannot regenerate themselves. With the current understanding that every adult tissue has its own intrinsic progenitor or stem cell, it is now clear that almost all tissues have regenerative potential partially related to their innate turnover dynamics. Moreover, it appears that a separate class of local cells originating as perivascular cells appears to provide regulatory oversight for localized tissue regeneration. The management of this regeneration oversight has a profound influence on the use of specific cells for cell therapies as a health care delivery tool set. The multipotent mesenchymal stem cell (MSC), now renamed the medicinal signaling cell, predominantly arises from pericytes released from broken and inflamed blood vessels and appears to function as both an immunomodulatory and a regeneration mediator. MSCs are being tested for their management capabilities to produce therapeutic outcomes in more than 480 clinical trials for a wide range of clinical conditions. Local MSCs function by managing the body’s primary repair and regeneration activities. Supplemental MSCs can be provided from either endogenous or exogenous sources of either allogeneic or autologous origin. This MSC-based therapy has the potential to change how health care is delivered. These medicinal cells are capable of sensing their surroundings. Also, by using its complex signaling circuitry, these cells organize site-specific regenerative responses as if these therapeutic cells were well-programmed modern computers. Given these facts, it appears that we are entering a new age of cellular medicine. Significance This report is a perspective from an active scientist and an active entrepreneur and commercial leader. It is neither a comprehensive review nor a narrowly focused treatise. The broad themes and the analogy to the working component of a computer and that of a cell are meant to draw several important scientific principles and health care themes together into the thesis that regenerative medicine is a constant throughout life and its management is the next frontier of health care. Mesenchymal stem cells are used as the central connection in the broad theme, not as multipotent progenitors but rather as an important control element in the natural local regeneration process. PMID:26019227

Inverse Relationship between Tumor Proliferation Markers and Connexin Expression in a Malignant Cardiac Tumor Originating from Mesenchymal Stem Cell Engineered Tissue in a Rat in vivo Model

PubMed Central

Spath, Cathleen; Schlegel, Franziska; Leontyev, Sergey; Mohr, Friedrich-Wilhelm; Dhein, Stefan

2013-01-01

Background: Recently, we demonstrated the beneficial effects of engineered heart tissues for the treatment of dilated cardiomyopathy in rats. For further development of this technique we started to produce engineered tissue (ET) from mesenchymal stem cells. Interestingly, we observed a malignant tumor invading the heart with an inverse relationship between proliferation markers and connexin expression. Methods: Commercial CD54+/CD90+/CD34−/CD45− bone marrow derived mesenchymal rat stem cells (cBM-MSC), characterized were used for production of mesenchymal stem-cell-ET (MSC-ET) by suspending them in a collagen I, matrigel-mixture and cultivating for 14 days with electrical stimulation. Three MSC-ET were implanted around the beating heart of adult rats for days. Another three MSC-ET were produced from freshly isolated rat bone marrow derived stem cells (sBM-MSC). Results: Three weeks after implantation of the MSC-ETs the hearts were surgically excised. While in 5/6 cases the ET was clearly distinguishable and was found as a ring containing mostly connective tissue around the heart, in 1/6 the heart was completely surrounded by a huge, undifferentiated, pleomorphic tumor originating from the cMSC-ET (cBM-MSC), classified as a high grade malignant sarcoma. Quantitatively we found a clear inverse relationship between cardiac connexin expression (Cx43, Cx40, or Cx45) and increased Ki-67 expression (Cx43: p < 0.0001, Cx45: p < 0.03, Cx40: p < 0.014). At the tumor-heart border there were significantly more Ki-67 positive cells (p = 0.001), and only 2% Cx45 and Ki-67-expressing cells, while the other connexins were nearly completely absent (p < 0.0001). Conclusion and Hypothesis: These observations strongly suggest the hypothesis, that invasive tumor growth is accompanied by reduction in connexins. This implicates that gap junction communication between tumor and normal tissue is reduced or absent, which could mean that growth and differentiation signals can not be exchanged. PMID:23616767

Exosomes and cardiovascular cell-cell communication.

PubMed

Poe, Adam J; Knowlton, Anne A

2018-05-15

Exosomes have become an important player in intercellular signaling. These lipid microvesicles can stably transfer miRNA, protein, and other molecules between cells and circulate throughout the body. Exosomes are released by almost all cell types and are present in most if not all biological fluids. The biologically active cargo carried by exosomes can alter the phenotype of recipient cells. Exosomes increasingly are recognized as having an important role in the progression and treatment of cardiac disease states. Injured cardiac cells can release exosomes with important pathological effects on surrounding tissue, in addition to effecting other organs. But of equal interest is the possible benefit(s) conferred by exosomes released from stem cells for use in treatment and possible repair of cardiac damage. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Bone Marrow Aspirate Concentrate for Cartilage Defects of the Knee: From Bench to Bedside Evidence.

PubMed

Cotter, Eric J; Wang, Kevin C; Yanke, Adam B; Chubinskaya, Susan

2018-04-01

Objective To critically evaluate the current basic science, translational, and clinical data regarding bone marrow aspirate concentrate (BMAC) in the setting of focal cartilage defects of the knee and describe clinical indications and future research questions surrounding the clinical utility of BMAC for treatment of these lesions. Design A literature search was performed using the PubMed and Ovid MEDLINE databases for studies in English (1980-2017) using keywords, including ["bone marrow aspirate" and "cartilage"], ["mesenchymal stem cells" and "cartilage"], and ["bone marrow aspirate" and "mesenchymal stem cells" and "orthopedics"]. A total of 1832 articles were reviewed by 2 independent authors and additional literature found through scanning references of cited articles. Results BMAC has demonstrated promising results in the clinical application for repair of chondral defects as an adjuvant procedure or as an independent management technique. A subcomponent of BMAC, bone marrow derived-mesenchymal stem cells (MSCs) possess the ability to differentiate into cells important for osteogenesis and chondrogenesis. Modulation of paracrine signaling is perhaps the most important function of BM-MSCs in this setting. In an effort to increase the cellular yield, authors have shown the ability to expand BM-MSCs in culture while maintaining phenotype. Conclusions Translational studies have demonstrated good clinical efficacy of BMAC both concomitant with cartilage restoration procedures, at defined time points after surgery, and as isolated injections. Early clinical data suggests BMAC may help stimulate a more robust hyaline cartilage repair tissue response. Numerous questions remain regarding BMAC usage, including cell source, cell expansion, optimal pathology, and injection timing and quantity.

Movers, Shakers, & Everyone in Between: Faculty Personas Surrounding Active Learning in the Undergraduate STEM Classroom

ERIC Educational Resources Information Center

Guy, Batsheva R.

2017-01-01

This qualitative study explores the attitudes that STEM (Science, Technology, Engineering, and Mathematics) faculty have about active learning (AL), the barriers that STEM faculty face when implementing AL, and what would encourage STEM faculty to use AL. Data was gathered using a modified Group-Level Assessment (GLA), a participatory method meant…

Labeling and Magnetic Resonance Imaging of Exosomes Isolated from Adipose Stem Cells.

PubMed

Busato, Alice; Bonafede, Roberta; Bontempi, Pietro; Scambi, Ilaria; Schiaffino, Lorenzo; Benati, Donatella; Malatesta, Manuela; Sbarbati, Andrea; Marzola, Pasquina; Mariotti, Raffaella

2017-06-19

Adipose stem cells (ASC) represent a promising therapeutic approach for neurodegenerative diseases. Most biological effects of ASC are probably mediated by extracellular vesicles, such as exosomes, which influence the surrounding cells. Current development of exosome therapies requires efficient and noninvasive methods to localize, monitor, and track the exosomes. Among imaging methods used for this purpose, magnetic resonance imaging (MRI) has advantages: high spatial resolution, rapid in vivo acquisition, and radiation-free operation. To be detectable with MRI, exosomes must be labeled with MR contrast agents, such as ultra-small superparamagnetic iron oxide nanoparticles (USPIO). Here, we set up an innovative approach for exosome labeling that preserves their morphology and physiological characteristics. We show that by labeling ASC with USPIO before extraction of nanovesicles, the isolated exosomes retain nanoparticles and can be visualized by MRI. The current work aims at validating this novel USPIO-based exosome labeling method by monitoring the efficiency of the labeling with MRI both in ASC and in exosomes. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Silent IL2RG Gene Editing in Human Pluripotent Stem Cells.

PubMed

Li, Li B; Ma, Chao; Awong, Geneve; Kennedy, Marion; Gornalusse, German; Keller, Gordon; Kaufman, Dan S; Russell, David W

2016-03-01

Many applications of pluripotent stem cells (PSCs) require efficient editing of silent chromosomal genes. Here, we show that a major limitation in isolating edited clones is silencing of the selectable marker cassette after homologous recombination and that this can be overcome by using a ubiquitous chromatin opening element (UCOE) promoter-driven transgene. We use this strategy to edit the silent IL2RG locus in human PSCs with a recombinant adeno-associated virus (rAAV)-targeting vector in the absence of potentially genotoxic, site-specific nucleases and show that IL2RG is required for natural killer and T-cell differentiation of human PSCs. Insertion of an active UCOE promoter into a silent locus altered the histone modification and cytosine methylation pattern of surrounding chromatin, but these changes resolved when the UCOE promoter was removed. This same approach could be used to correct IL2RG mutations in X-linked severe combined immunodeficiency patient-derived induced PSCs (iPSCs), to prevent graft versus host disease in regenerative medicine applications, or to edit other silent genes.

Peritubular Myoid Cells Participate in Male Mouse Spermatogonial Stem Cell Maintenance

PubMed Central

Chen, Liang-Yu; Brown, Paula R.; Willis, William B.

2014-01-01

Peritubular myoid (PM) cells surround the seminiferous tubule and together with Sertoli cells form the cellular boundary of the spermatogonial stem cell (SSC) niche. However, it remains unclear what role PM cells have in determining the microenvironment in the niche required for maintenance of the ability of SSCs to undergo self-renewal and differentiation into spermatogonia. Mice with a targeted disruption of the androgen receptor gene (Ar) in PM cells experienced a progressive loss of spermatogonia, suggesting that PM cells require testosterone (T) action to produce factors influencing SSC maintenance in the niche. Other studies showed that glial cell line-derived neurotrophic factor (GDNF) is required for SSC self-renewal and differentiation of SSCs in vitro and in vivo. This led us to hypothesize that T-regulated GDNF expression by PM cells contributes to the maintenance of SSCs. This hypothesis was tested using an adult mouse PM cell primary culture system and germ cell transplantation. We found that T induced GDNF expression at the mRNA and protein levels in PM cells. Furthermore, when thymus cell antigen 1-positive spermatogonia isolated from neonatal mice were cocultured with PM cells with or without T and transplanted to the testes of germ cell-depleted mice, the number and length of transplant-derived colonies was increased considerably by in vitro T treatment. These results support the novel hypothesis that T-dependent regulation of GDNF expression in PM cells has a significant influence on the microenvironment of the niche and SSC maintenance. PMID:25181385

Exosomes Function in Tumor Immune Microenvironment.

PubMed

Huang, Yin; Liu, Keli; Li, Qing; Yao, Yikun; Wang, Ying

2018-01-01

Immune cells and mesenchymal stem/stromal cells are the major cellular components in tumor microenvironment that actively migrate to tumor sites by sensing "signals" released from tumor cells. Together with other stromal cells, they form the soil for malignant cell progression. In the crosstalk between tumor cells and its surrounded microenvironment, exosomes exert multiple functions in shaping tumor immune responses. In tumor cells, their exosomes can lead to pro-tumor immune responses, whereas in immune cells, their derived exosomes can operate on tumor cells and regulate their ability to growth, metastasis, even reaction to chemotherapy. Employing exosomes as vehicles for the delivery products to initiate anti-tumor immune responses has striking therapeutic effects on tumor progression. Thus, exosomes are potential therapeutic targets in tumor-related clinical conditions. Here we discuss the role of exosomes in regulating tumor immune microenvironment and future indications for the clinical application of exosomes.

Tree water relations can trigger monoterpene emissions from Scots pine stems during spring recovery

NASA Astrophysics Data System (ADS)

Vanhatalo, A.; Chan, T.; Aalto, J.; Korhonen, J. F.; Kolari, P.; Hölttä, T.; Nikinmaa, E.; Bäck, J.

2015-09-01

Tree canopies are known to emit large amounts of VOCs (volatile organic compounds) such as monoterpenes into the surrounding air. High VOC emission rates from boreal forests have been observed during the transition from winter to summer activity. The most important sources of these are considered to be the green foliage, understory vegetation and soil organisms, but emissions from the living stand woody compartments have so far not been quantified. We analyzed whether the non-foliar components could partially explain the springtime high emission rates. We measured the monoterpene emissions from Scots pine (Pinus sylvestris L.) stem and shoots during the dehardening phase of trees in field conditions in two consecutive springs. We observed a large, transient monoterpene burst from the stem, while the shoot monoterpene emissions remained low. The burst lasted about 12 h. Simultaneously, an unusual nighttime sap flow and a non-systematic diurnal pattern of tree diameter were detected. Hence, we suggest that the monoterpene burst was a consequence of the recovery of the stem from wintertime, and likely related to the refilling of embolized tracheids and/or phenological changes in the living cells of the stem. This indicates that the dominant processes and environmental drivers triggering the monoterpene emissions are different between the stem and the foliage.

Amyloid plaque structure and cell surface interactions of β-amyloid fibrils revealed by electron tomography

PubMed Central

Han, Shen; Kollmer, Marius; Markx, Daniel; Claus, Stephanie; Walther, Paul; Fändrich, Marcus

2017-01-01

The deposition of amyloid fibrils as plaques is a key feature of several neurodegenerative diseases including in particular Alzheimer’s. This disease is characterized, if not provoked, by amyloid aggregates formed from Aβ peptide that deposit inside the brain or are toxic to neuronal cells. We here used scanning transmission electron microscopy (STEM) to determine the fibril network structure and interactions of Aβ fibrils within a cell culture model of Alzheimer’s disease. STEM images taken from the formed Aβ amyloid deposits revealed three main types of fibril network structures, termed amorphous meshwork, fibril bundle and amyloid star. All three were infiltrated by different types of lipid inclusions from small-sized exosome-like structures (50–100 nm diameter) to large-sized extracellular vesicles (up to 300 nm). The fibrils also presented strong interactions with the surrounding cells such that fibril bundles extended into tubular invaginations of the plasma membrane. Amyloid formation in the cell model was previously found to have an intracellular origin and we show here that it functionally destroys the integrity of the intracellular membranes as it leads to lysosomal leakage. These data provide a mechanistic link to explain why intracellular fibril formation is toxic to the cell. PMID:28240273

Specific binding of a HeLa cell nuclear protein to RNA sequences in the human immunodeficiency virus transactivating region.

PubMed Central

Gaynor, R; Soultanakis, E; Kuwabara, M; Garcia, J; Sigman, D S

1989-01-01

The transactivator protein, tat, encoded by the human immunodeficiency virus is a key regulator of viral transcription. Activation by the tat protein requires sequences downstream of the transcription initiation site called the transactivating region (TAR). RNA derived from the TAR is capable of forming a stable stem-loop structure and the maintenance of both the stem structure and the loop sequences located between +19 and +44 is required for complete in vivo activation by tat. Gel retardation assays with RNA from both wild-type and mutant TAR constructs generated in vitro with SP6 polymerase indicated specific binding of HeLa nuclear proteins to the TAR. To characterize this RNA-protein interaction, a method of chemical "imprinting" has been developed using photoactivated uranyl acetate as the nucleolytic agent. This reagent nicks RNA under physiological conditions at all four nucleotides in a reaction that is independent of sequence and secondary structure. Specific interaction of cellular proteins with TAR RNA could be detected by enhanced cleavages or imprints surrounding the loop region. Mutations that either disrupted stem base-pairing or extensively changed the primary sequence resulted in alterations in the cleavage pattern of the TAR RNA. Structural features of the TAR RNA stem-loop essential for tat activation are also required for specific binding of the HeLa cell nuclear protein. Images PMID:2544877

7 CFR 51.3064 - Damage.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., CERTIFICATION, AND STANDARDS) United States Standards for Florida Avocados Definitions § 51.3064 Damage. Damage... inch in width, or when healed and the appearance is materially affected; (b) Pulled stems when the exposed stem cavity is excessively deep, or when skin surrounding the stem cavity is more than slightly...

7 CFR 51.3064 - Damage.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., CERTIFICATION, AND STANDARDS) United States Standards for Florida Avocados Definitions § 51.3064 Damage. Damage... inch in width, or when healed and the appearance is materially affected; (b) Pulled stems when the exposed stem cavity is excessively deep, or when skin surrounding the stem cavity is more than slightly...

Mesenchymal stem cells cultured on magnetic nanowire substrates

NASA Astrophysics Data System (ADS)

Perez, Jose E.; Ravasi, Timothy; Kosel, Jürgen

2017-02-01

Stem cells have been shown to respond to extracellular mechanical stimuli by regulating their fate through the activation of specific signaling pathways. In this work, an array of iron nanowires (NWs) aligned perpendicularly to the surface was fabricated by pulsed electrodepositon in porous alumina templates followed by a partial removal of the alumina to reveal 2-3 μm of the NWs. This resulted in alumina substrates with densely arranged NWs of 33 nm in diameter separated by 100 nm. The substrates were characterized by scanning electron microscopy (SEM) energy dispersive x-ray analysis and vibrating sample magnetometer. The NW array was then used as a platform for the culture of human mesenchymal stem cells (hMSCs). The cells were stained for the cell nucleus and actin filaments, as well as immuno-stained for the focal adhesion protein vinculin, and then observed by fluorescence microscopy in order to characterize their spreading behavior. Calcein AM/ethidium homodimer-1 staining allowed the determination of cell viability. The interface between the cells and the NWs was studied using SEM. Results showed that hMSCs underwent a re-organization of actin filaments that translated into a change from an elongated to a spherical cell shape. Actin filaments and vinculin accumulated in bundles, suggesting the attachment and formation of focal adhesion points of the cells on the NWs. Though the overall number of cells attached on the NWs was lower compared to the control, the attached cells maintained a high viability (>90%) for up to 6 d. Analysis of the interface between the NWs and the cells confirmed the re-organization of F-actin and revealed the adhesion points of the cells on the NWs. Additionally, a net of filopodia surrounded each cell, suggesting the probing of the array to find additional adhesion points. The cells maintained their round shape for up to 6 d of culture. Overall, the NW array is a promising nanostructured platform for studying and influencing hMSCs differentiation.

The role of social and cognitive processes in the relationship between fear network and psychological distress among parents of children undergoing hematopoietic stem cell transplantation.

PubMed

Virtue, Shannon Myers; Manne, Sharon; Mee, Laura; Bartell, Abraham; Sands, Stephen; Ohman-Strickland, Pamela; Gajda, Tina Marie

2014-09-01

The current study examined whether cognitive and social processing variables mediated the relationship between fear network and depression among parents of children undergoing hematopoietic stem cell transplant (HSCT). Parents whose children were initiating HSCT (N = 179) completed survey measures including fear network, Beck Depression Inventory, cognitive processing variables (positive reappraisal and self-blame) and social processing variables (emotional support and holding back from sharing concerns). Fear network was positively correlated with depression (p < .001). Self-blame and holding back emerged as individual partial mediators in the relationship between fear network and depression. Together they accounted for 34.3% of the variance in the relationship between fear network and depression. Positive reappraisal and emotional support did not have significant mediating effects. Social and cognitive processes, specifically self-blame and holding back from sharing concerns, play a negative role in parents' psychological adaptation to fears surrounding a child's HSCT.

The Role of Social and Cognitive Processes in the Relationship between Fear Network and Psychological Distress among Parents of Children Undergoing Hematopoietic Stem Cell Transplantation

PubMed Central

Virtue, Shannon Myers; Manne, Sharon; Mee, Laura; Bartell, Abraham; Sands, Stephen; Ohman-Strickland, Pamela; Gajda, Tina Marie

2014-01-01

The current study examined whether cognitive and social processing variables mediated the relationship between fear network and depression among parents of children undergoing hematopoietic stem cell transplant (HSCT). Parents whose children were initiating HSCT (N = 179) completed survey measures including fear network, Beck Depression Inventory (BDI), cognitive processing variables (positive reappraisal and self-blame) and social processing variables (emotional support and holding back from sharing concerns). Fear network was positively correlated with depression (p < .001). Self-blame and holding back emerged as individual partial mediators in the relationship between fear network and depression. Together they accounted for 34.3% of the variance in the relationship between fear network and depression. Positive reappraisal and emotional support did not have significant mediating effects. Social and cognitive processes, specifically self-blame and holding back from sharing concerns, play a negative role in parents’ psychological adaptation to fears surrounding a child’s HSCT. PMID:25081956

Rapid fusion between mesenchymal stem cells and cardiomyocytes yields electrically active, non-contractile hybrid cells.

PubMed

Shadrin, Ilya Y; Yoon, Woohyun; Li, Liqing; Shepherd, Neal; Bursac, Nenad

2015-07-10

Cardiac cell therapies involving bone marrow-derived human mesenchymal stem cells (hMSCs) have shown promising results, although their mechanisms of action are still poorly understood. Here, we investigated direct interactions between hMSCs and cardiomyocytes in vitro. Using a genetic Ca(2+) indicator gCaMP3 to efficiently label hMSCs in co-cultures with neonatal rat ventricular myocytes (NRVMs), we determined that 25-40% of hMSCs (from 4 independent donors) acquired periodic Ca(2+) transients and cardiac markers through spontaneous fusion with NRVMs. Sharp electrode and voltage-clamp recordings in fused cells showed action potential properties and Ca(2+) current amplitudes in between those of non-fused hMSCs and NRVMs. Time-lapse video-microscopy revealed the first direct evidence of active fusion between hMSCs and NRVMs within several hours of co-culture. Application of blebbistatin, nifedipine or verapamil caused complete and reversible inhibition of fusion, suggesting potential roles for actomyosin bridging and Ca(2+) channels in the fusion process. Immunostaining for Cx43, Ki67, and sarcomeric α-actinin showed that fused cells remain strongly coupled to surrounding NRVMs, but downregulate sarcomeric structures over time, acquiring a non-proliferative and non-contractile phenotype. Overall, these results describe the phenotype and mechanisms of hybrid cell formation via fusion of hMSCs and cardiomyocytes with potential implications for cardiac cell therapy.

7 CFR 51.3069 - Very serious damage.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Florida Avocados Definitions § 51.3069... quality; (b) Pulled stems when the skin surrounding the exposed stem cavity is torn more than an aggregate...

7 CFR 51.3069 - Very serious damage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Florida Avocados Definitions § 51.3069... quality; (b) Pulled stems when the skin surrounding the exposed stem cavity is torn more than an aggregate...

Descending pathways to the cutaneus trunci muscle motoneuronal cell group in the cat

NASA Technical Reports Server (NTRS)

Holstege, Gert; Blok, Bertil F.

1989-01-01

The descending pathways to the motoneuronal cell group of the cutaneous trunci muscle (CTM) of the cat were investigated by injecting H-3-labeled lucine into the brain stem, the diencephalon, or the C1, C2, C6, and C8 segments of the spinal cord, and examining fixed autoradiographic sections of the spinal cord and brain regions. Results demonstrate presence of specific supraspinal projectons to the CTM motor nucleus originating in the contralateral nucleus retroambiguous and the ipsilateral dorsolateral pontine tegmentum. Results also suggest that propriospinal pathways to the CTM motor nucleus originating in the cervical cord do not exist, although these propriospinal projections to all other motoneuronal cell groups surrounding the CTM nucleus are very strong.

Matrix Property-Controlled Stem Cell Differentiation for Cardiac and Skeletal Tissue Regeneration

NASA Astrophysics Data System (ADS)

Xu, Yanyi

When ischemia, caused by diseases such as myocardial infarction (MI) or atherosclerotic peripheral artery disease (PAD), happens in myocardium or skeletal muscles, the depletion of oxygen and nutrients can cause the immediate death of muscle cells, the formation of stiff scar tissues, followed by the mechanical and functional properties loss of heart/skeletal muscles. In order to treat these diseases, it's necessary to: 1). fast re-establish the blood flow of ischemic tissues; 2). fully regenerate the cardiac/skeletal muscles to restore the tissue functions. One of the widely used approaches to reach these treatment goals is stem cell transplantation. By using novel biomaterial-based scaffolds (gels, foams or fibrous networks), stem cells may be delivered into the injured area, differentiate into cardiomyocytes/myofibers and help the regeneration of local tissues. In the first part of this work, physical induction approaches for stem cell differentiation is presented. Using an electrospinning method, fibrous scaffolds based on hydrogel and polyurethane (PU) were fabricated and cardiac differentiation of cardio-sphere derived cells (CDCs) was successfully induced through the control of scaffold mechanical and morphological properties (fiber diameter, density, alignment, single fiber modulus and scaffold macro modulus). In a hydrogel system, the matrix modulus was successfully decoupled from the chemical structure, composition and water content properties, and a matrix tensile modulus of around 20kPa was found to better induce the myogenic differentiation of mesenchymal stem cells (MSCs) cultured under normal condition. In the other hand, due to the harsh local environment caused by ischemia, the transplanted cells usually have low survival and differentiation rates. To solve this problem, cells were delivered in hydrogels with angiogenesis factor basic fibroblast growth factor (bFGF) or oxygen release microspheres (ORM) to conquer the local low oxygen and low nutrient conditions. The second part of this work focuses on the application of this delivery system in vivo using a mice hindlimb ischemia model. Results showed that MSC survival and myogenic differentiation rates were significantly improved both in vitro and in vivo with the delivery of bFGF or ORM under ischemic condition. In addition, a dramatic increase of muscle fiber regeneration, blood flow recovery as well as the mechanical/functional (muscle contractility, fatigue resistance and mice running ability) properties was observed. These results indicate the great potential of this cell-gel-biomolecule system in the treatment of muscle regeneration. To better understand how the matrix modulus affects the stem cell differentiation, we developed a novel approach using digital image correlation (DIC) and finite element modeling (FEM) to calculate the cell-generated tractions. This is presented in the third part of this work, and our results demonstrated that MSCs with higher myogenic differentiation exerted larger tractions to their surrounding matrix.

Gravitropism in Higher Plant Shoots 1

PubMed Central

Wheeler, Raymond M.; White, Rosemary G.; Salisbury, Frank B.

1986-01-01

Ethylene at 1.0 and 10.0 cubic centimeters per cubic meter decreased the rate of gravitropic bending in stems of cocklebur (Xanthium strumarium L.) and tomato (Lycopersicon esculentum Mill), but 0.1 cubic centimeter per cubic meter ethylene had little effect. Treating cocklebur plants with 1.0 millimolar aminoethoxyvinylglycine (AVG) (ethylene synthesis inhibitor) delayed stem bending compared with controls, but adding 0.1 cubic centimeter per cubic meter ethylene in the surrounding atmosphere (or applying 0.1% ethephon solution) partially restored the rate of bending of AVG-treated plants. Ethylene increases in bending stems, and AVG inhibits this. Virtually all newly synthesized ethylene appeared in bottom halves of horizontal stems, where ethylene concentrations were as much as 100 times those in upright stems or in top halves of horizontal stems. This was especially true when horizontal stems were physically restrained from bending. Ethylene might promote cell elongation in bottom tissues of a horizontal stem or indicate other factors there (e.g. a large amount of `functioning' auxin). Or top and bottom tissues may become differentially sensitive to ethylene. Auxin applied to one side of a vertical stem caused extreme bending away from that side; gibberellic acid, kinetin, and abscisic acid were without effect. Acidic ethephon solutions applied to one side of young seedlings of cocklebur, tomato, sunflower (Helianthus annuus L.), and soybean (Glycine max [L.] Merr.) caused bending away from that side, but neutral ethephon solutions did not cause bending. Buffered or unbuffered acid (HCl) caused similar bending. Neutral ethephon solutions produced typical ethylene symptoms (i.e. epinasty, inhibition of stem elongation). HCl or acidic ethephon applied to the top of horizontal stems caused downward bending, but these substances applied to the bottom of such stems inhibited growth and upward bending—an unexpected result. PMID:11539089

Macrophage-derived oncostatin M contributes to human and mouse neurogenic heterotopic ossifications

PubMed Central

Torossian, Frédéric; Guerton, Bernadette; Anginot, Adrienne; Alexander, Kylie A.; Desterke, Christophe; Soave, Sabrina; Tseng, Hsu-Wen; Arouche, Nassim; Boutin, Laetitia; Kulina, Irina; Salga, Marjorie; Jose, Beulah; Pettit, Allison R.; Clay, Denis; Vlachos, Erica; Genet, Guillaume; Debaud, Charlotte; Denormandie, Philippe; Genet, François; Sims, Natalie A.; Banzet, Sébastien; Levesque, Jean-Pierre; Lataillade, Jean-Jacques; Le Bousse-Kerdilès, Marie-Caroline

2017-01-01

Neurogenic heterotopic ossification (NHO) is the formation of ectopic bone generally in muscles surrounding joints following spinal cord or brain injury. We investigated the mechanisms of NHO formation in 64 patients and a mouse model of spinal cord injury–induced NHO. We show that marrow from human NHOs contains hematopoietic stem cell (HSC) niches, in which mesenchymal stromal cells (MSCs) and endothelial cells provide an environment supporting HSC maintenance, proliferation, and differentiation. The transcriptomic signature of MSCs from NHOs shows a neuronal imprinting associated with a molecular network required for HSC support. We demonstrate that oncostatin M (OSM) produced by activated macrophages promotes osteoblastic differentiation and mineralization of human muscle-derived stromal cells surrounding NHOs. The key role of OSM was confirmed using an experimental model of NHO in mice defective for the OSM receptor (OSMR). Our results provide strong evidence that macrophages contribute to NHO formation through the osteogenic action of OSM on muscle cells within an inflammatory context and suggest that OSM/OSMR could be a suitable therapeutic target. Altogether, the evidence of HSCs in ectopic bones growing at the expense of soft tissue in spinal cord/brain-injured patients indicates that inflammation and muscle contribute to HSC regulation by the brain-bone-blood triad. PMID:29093266

EphrinB3 restricts endogenous neural stem cell migration after traumatic brain injury.

PubMed

Dixon, Kirsty J; Mier, Jose; Gajavelli, Shyam; Turbic, Alisa; Bullock, Ross; Turnley, Ann M; Liebl, Daniel J

2016-11-01

Traumatic brain injury (TBI) leads to a series of pathological events that can have profound influences on motor, sensory and cognitive functions. Conversely, TBI can also stimulate neural stem/progenitor cell proliferation leading to increased numbers of neuroblasts migrating outside their restrictive neurogenic zone to areas of damage in support of tissue integrity. Unfortunately, the factors that regulate migration are poorly understood. Here, we examine whether ephrinB3 functions to restrict neuroblasts from migrating outside the subventricular zone (SVZ) and rostral migratory stream (RMS). We have previously shown that ephrinB3 is expressed in tissues surrounding these regions, including the overlying corpus callosum (CC), and is reduced after controlled cortical impact (CCI) injury. Our current study takes advantage of ephrinB3 knockout mice to examine the influences of ephrinB3 on neuroblast migration into CC and cortex tissues after CCI injury. Both injury and/or ephrinB3 deficiency led to increased neuroblast numbers and enhanced migration outside the SVZ/RMS zones. Application of soluble ephrinB3-Fc molecules reduced neuroblast migration into the CC after injury and limited neuroblast chain migration in cultured SVZ explants. Our findings suggest that ephrinB3 expression in tissues surrounding neurogenic regions functions to restrict neuroblast migration outside the RMS by limiting chain migration. Copyright © 2016 Michael Boutros, German Cancer Research Center, Heidelberg, Germany. Published by Elsevier B.V. All rights reserved.

Cryo-Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)-in-SEM for Bio- and Organo-Mineral Interface Characterization in the Environment.

PubMed

Wille, Guillaume; Hellal, Jennifer; Ollivier, Patrick; Richard, Annie; Burel, Agnes; Jolly, Louis; Crampon, Marc; Michel, Caroline

2017-12-01

Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy). Fluorescent microscopy revealed that nZVI were embedded in the biofilm structure as aggregates but the resolution was insufficient to observe individual nZVI. Cryo-scanning electron microscopy (SEM) observations showed nZVI aggregates close to bacteria, but it was not possible to confirm direct interactions between nZVI and cell membranes. Scanning transmission electron microscopy in the SEM (STEM-in-SEM) showed that nZVI aggregates could enter the biofilm to a depth of 7-11 µm. Bacteria were surrounded by a ring of extracellular polymeric substances (EPS) preventing direct nZVI/membrane interactions. STEM/EDS mapping revealed a co-localization of nZVI aggregates with lectins suggesting a potential role of EPS in nZVI embedding. Thus, the combination of divergent microscopy approaches is a good approach to better understand and characterize biofilm/metal interactions.

Investigating Preservice STEM Teacher Conceptions of STEM Education

NASA Astrophysics Data System (ADS)

Radloff, Jeff; Guzey, Selcen

2016-10-01

Surrounding the national emphasis on improving STEM education, effective STEM educators are required. Connected, yet often overlooked, is the need for effective preservice STEM teaching instruction for incoming educators. At a basic level, preservice STEM teacher education should include STEM content, pedagogy, and conceptualization. However, the literature suggests no leading conception of STEM education, and little is known about how preservice STEM teachers are conceptualizing STEM education. In order to explore preservice STEM teacher conceptions of STEM education, preservice teachers at a large, Midwestern research university were given an open-ended survey eliciting both textual and visual responses. Here, we report and discuss the results of employing this instrument in relation with the current STEM conceptualization literature.

Muscle satellite cells adopt divergent fates

PubMed Central

Zammit, Peter S.; Golding, Jon P.; Nagata, Yosuke; Hudon, Valérie; Partridge, Terence A.; Beauchamp, Jonathan R.

2004-01-01

Growth, repair, and regeneration of adult skeletal muscle depends on the persistence of satellite cells: muscle stem cells resident beneath the basal lamina that surrounds each myofiber. However, how the satellite cell compartment is maintained is unclear. Here, we use cultured myofibers to model muscle regeneration and show that satellite cells adopt divergent fates. Quiescent satellite cells are synchronously activated to coexpress the transcription factors Pax7 and MyoD. Most then proliferate, down-regulate Pax7, and differentiate. In contrast, other proliferating cells maintain Pax7 but lose MyoD and withdraw from immediate differentiation. These cells are typically located in clusters, together with Pax7−ve progeny destined for differentiation. Some of the Pax7+ve/MyoD−ve cells then leave the cell cycle, thus regaining the quiescent satellite cell phenotype. Significantly, noncycling cells contained within a cluster can be stimulated to proliferate again. These observations suggest that satellite cells either differentiate or switch from terminal myogenesis to maintain the satellite cell pool. PMID:15277541

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

PubMed Central

Arzumanyan, Alla; Kulathinal, Rob J.; Blain, Stacy W.; Holcombe, Randall F.; Mahajna, Jamal; Marino, Maria; Martinez-Chantar, Maria L.; Nawroth, Roman; Sanchez-Garcia, Isidro; Sharma, Dipali; Saxena, Neeraj K.; Singh, Neetu; Vlachostergios, Panagiotis J.; Guo, Shanchun; Honoki, Kanya; Fujii, Hiromasa; Georgakilas, Alexandros G.; Amedei, Amedeo; Niccolai, Elena; Amin, Amr; Ashraf, S. Salman; Boosani, Chandra S.; Guha, Gunjan; Ciriolo, Maria Rosa; Aquilano, Katia; Chen, Sophie; Mohammed, Sulma I.; Azmi, Asfar S.; Bhakta, Dipita; Halicka, Dorota; Nowsheen, Somaira

2016-01-01

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). This data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression. PMID:25892662

SDF-1 overexpression by mesenchymal stem cells enhances GAP-43-positive axonal growth following spinal cord injury.

PubMed

Stewart, Andrew Nathaniel; Matyas, Jessica Jane; Welchko, Ryan Matthew; Goldsmith, Alison Delanie; Zeiler, Sarah Elizabeth; Hochgeschwender, Ute; Lu, Ming; Nan, Zhenhong; Rossignol, Julien; Dunbar, Gary Leo

2017-01-01

Utilizing genetic overexpression of trophic molecules in cell populations has been a promising strategy to develop cell replacement therapies for spinal cord injury (SCI). Over-expressing the chemokine, stromal derived factor-1 (SDF-1α), which has chemotactic effects on many cells of the nervous system, offers a promising strategy to promote axonal regrowth following SCI. The purpose of this study was to explore the effects of human SDF-1α, when overexpressed by mesenchymal stem cells (MSCs), on axonal growth and motor behavior in a contusive rat model of SCI. Using a transwell migration assay, the paracrine effects of MSCs, which were engineered to secrete human SDF-1α (SDF-1-MSCs), were assessed on cultured neural stem cells (NSCs). For in vivo analyses, the SDF-1-MSCs, unaltered MSCs, or Hanks Buffered Saline Solution (vehicle) were injected into the lesion epicenter of rats at 9-days post-SCI. Behavior was analyzed for 7-weeks post-injury, using the Basso, Beattie, and Bresnahan (BBB) scale of locomotor functions. Immunohistochemistry was performed to evaluate major histopathological outcomes, including gliosis, inflammation, white matter sparing, and cavitation. New axonal outgrowth was characterized using immunohistochemistry against the neuron specific growth-associated protein-43 (GAP-43). The results of these experiments demonstrate that the overexpression of SDF-1α by MSCs can enhance the migration of NSCs in vitro. Although only modest functional improvements were observed following transplantation of SDF-1-MSCs, a significant reduction in cavitation surrounding the lesion, and an increased density of GAP-43-positive axons inside the SCI lesion/graft site were found. The results from these experiments support the potential role for utilizing SDF-1α as a treatment for enhancing growth and regeneration of axons after traumatic SCI.

Use of trimetasphere metallofullerene MRI contrast agent for the non-invasive longitudinal tracking of stem cells in the lung

PubMed Central

Murphy, Sean V.; Hale, Austin; Reid, Tanya; Olson, John; Kidiyoor, Amritha; Tan, Josh; Zhou, Zhiguo; Jackson, John; Atala, Anthony

2016-01-01

Magnetic Resonance Imaging (MRI) is a commonly used, non-invasive imaging technique that provides visualization of soft tissues with high spatial resolution. In both a research and clinical setting, the major challenge has been identifying a non-invasive and safe method for longitudinal tracking of delivered cells in vivo. The labeling and tracking of contrast agent labeled cells using MRI has the potential to fulfill this need. Contrast agents are often used to enhance the image contrast between the tissue of interest and surrounding tissues with MRI. The most commonly used MRI contrast agents contain Gd(III) ions. However, Gd(III) ions are highly toxic in their ionic form, as they tend to accumulate in the liver, spleen, kidney and bones and block calcium channels. Endohedral metallofullerenes such as trimetallic nitride endohedral metallofullerenes (Trimetasphere®) are one unique class of fullerene molecules where a Gd3N cluster is encapsulated inside a C80 carbon cage referred to as Gd3N@C80. These endohedral metallofullerenes have several advantages over small chelated Gd(III) complexes such as increased stability of the Gd(III) ion, minimal toxic effects, high solubility in water and high proton relativity. In this study, we describe the evaluation of gadolinium-based Trimetasphere® positive contrast agent for the in vitro labeling and in vivo tracking of human amniotic fluid-derived stem cells within lung tissue. In addition, we conducted a ‘proof-of-concept’ experiment demonstrating that this methodology can be used to track the homing of stem cells to injured lung tissue and provide longitudinal analysis of cell localization over an extended time course. PMID:26546729

Use of trimetasphere metallofullerene MRI contrast agent for the non-invasive longitudinal tracking of stem cells in the lung.

PubMed

Murphy, Sean V; Hale, Austin; Reid, Tanya; Olson, John; Kidiyoor, Amritha; Tan, Josh; Zhou, Zhiguo; Jackson, John; Atala, Anthony

2016-04-15

Magnetic Resonance Imaging (MRI) is a commonly used, non-invasive imaging technique that provides visualization of soft tissues with high spatial resolution. In both a research and clinical setting, the major challenge has been identifying a non-invasive and safe method for longitudinal tracking of delivered cells in vivo. The labeling and tracking of contrast agent labeled cells using MRI has the potential to fulfill this need. Contrast agents are often used to enhance the image contrast between the tissue of interest and surrounding tissues with MRI. The most commonly used MRI contrast agents contain Gd(III) ions. However, Gd(III) ions are highly toxic in their ionic form, as they tend to accumulate in the liver, spleen, kidney and bones and block calcium channels. Endohedral metallofullerenes such as trimetallic nitride endohedral metallofullerenes (Trimetasphere®) are one unique class of fullerene molecules where a Gd3N cluster is encapsulated inside a C80 carbon cage referred to as Gd3N@C80. These endohedral metallofullerenes have several advantages over small chelated Gd(III) complexes such as increased stability of the Gd(III) ion, minimal toxic effects, high solubility in water and high proton relativity. In this study, we describe the evaluation of gadolinium-based Trimetasphere® positive contrast agent for the ​in vitro labeling and in vivo tracking of human amniotic fluid-derived stem cells within lung tissue. In addition, we conducted a 'proof-of-concept' experiment demonstrating that this methodology can be used to track the homing of stem cells to injured lung tissue and provide longitudinal analysis of cell localization over an extended time course. Copyright © 2015 Elsevier Inc. All rights reserved.

Planarians as a Model to Assess In Vivo the Role of Matrix Metalloproteinase Genes during Homeostasis and Regeneration

PubMed Central

Isolani, Maria Emilia; Abril, Josep F.; Saló, Emili; Deri, Paolo; Bianucci, Anna Maria; Batistoni, Renata

2013-01-01

Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results have high potential to generate significant information for development of regenerative and anti cancer therapies. PMID:23405188

Planarians as a model to assess in vivo the role of matrix metalloproteinase genes during homeostasis and regeneration.

PubMed

Isolani, Maria Emilia; Abril, Josep F; Saló, Emili; Deri, Paolo; Bianucci, Anna Maria; Batistoni, Renata

2013-01-01

Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results have high potential to generate significant information for development of regenerative and anti cancer therapies.

Lab-On-Chip Clinorotation System for Live-Cell Microscopy Under Simulated Microgravity

NASA Technical Reports Server (NTRS)

Yew, Alvin G.; Atencia, Javier; Chinn, Ben; Hsieh, Adam H.

2013-01-01

Cells in microgravity are subject to mechanical unloading and changes to the surrounding chemical environment. How these factors jointly influence cellular function is not well understood. We can investigate their role using ground-based analogues to spaceflight, where mechanical unloading is simulated through the time-averaged nullification of gravity. The prevailing method for cellular microgravity simulation is to use fluid-filled containers called clinostats. However, conventional clinostats are not designed for temporally tracking cell response, nor are they able to establish dynamic fluid environments. To address these needs, we developed a Clinorotation Time-lapse Microscopy (CTM) system that accommodates lab-on- chip cell culture devices for visualizing time-dependent alterations to cellular behavior. For the purpose of demonstrating CTM, we present preliminary results showing time-dependent differences in cell area between human mesenchymal stem cells (hMSCs) under modeled microgravity and normal gravity.

Lab-On-Chip Clinorotation System for Live-Cell Microscopy Under Simulated Microgravity

NASA Technical Reports Server (NTRS)

Yew, Alvin G.; Atencia, Javier; Chinn, Ben; Hsieh, Adam H.

1980-01-01

Cells in microgravity are subject to mechanical unloading and changes to the surrounding chemical environment. How these factors jointly influence cellular function is not well understood. We can investigate their role using ground-based analogues to spaceflight, where mechanical unloading is simulated through the time-averaged nullification of gravity. The prevailing method for cellular microgravity simulation is to use fluid-filled containers called clinostats. However, conventional clinostats are not designed for temporally tracking cell response, nor are they able to establish dynamic fluid environments. To address these needs, we developed a Clinorotation Time-lapse Microscopy (CTM) system that accommodates lab-on- chip cell culture devices for visualizing time-dependent alterations to cellular behavior. For the purpose of demonstrating CTM, we present preliminary results showing time-dependent differences in cell area between human mesenchymal stem cells (hMSCs) under modeled microgravity and normal gravity.

Establishment of goat embryonic stem cells from in vivo produced blastocyst-stage embryos.

PubMed

Behboodi, E; Bondareva, A; Begin, I; Rao, K; Neveu, N; Pierson, J T; Wylie, C; Piero, F D; Huang, Y J; Zeng, W; Tanco, V; Baldassarre, H; Karatzas, C N; Dobrinski, I

2011-03-01

Embryonic stem (ES) cells with the capacity for germ line transmission have only been verified in mouse and rat. Methods for derivation, propagation, and differentiation of ES cells from domestic animals have not been fully established. Here, we describe derivation of ES cells from goat embryos. In vivo-derived embryos were cultured on goat fetal fibroblast feeders. Embryos either attached to the feeder layer or remained floating and expanded in culture. Embryos that attached showed a prominent inner cell mass (ICM) and those that remained floating formed structures resembling ICM disks surrounded by trophectodermal cells. ICM cells and embryonic disks were isolated mechanically, cultured on feeder cells in the presence of hLIF, and outgrown into ES-like colonies. Two cell lines were cultured for 25 passages and stained positive for alkaline phosphatase, POU5F1, NANOG, SOX2, SSEA-1, and SSEA-4. Embryoid bodies formed in suspension culture without hLIF. One cell line was cultured for 2 years (over 120 passages). This cell line differentiated in vitro into epithelia and neuronal cells, and could be stably transfected and selected for expression of a fluorescent marker. When cells were injected into SCID mice, teratomas were identified 5-6 weeks after transplantation. Expression of known ES cell markers, maintenance in vitro for 2 years in an undifferentiated state, differentiation in vitro, and formation of teratomas in immunodeficient mice provide evidence that the established cell line represents goat ES cells. This also is the first report of teratoma formation from large animal ES cells. Copyright © 2011 Wiley-Liss, Inc.

SCAPs Regulate Differentiation of DFSCs During Tooth Root Development in Swine

PubMed Central

Wu, Xiaoshan; Hu, Lei; Li, Yan; Li, Yang; Wang, Fu; Ma, Ping; Wang, Jinsong; Zhang, Chunmei; Jiang, Canhua; Wang, Songlin

2018-01-01

The tooth root transmits and balances occlusal forces through the periodontium to the alveolar bone. The periodontium, including the gingiva, the periodontal ligament, the cementum and the partial alveolar bone, derives from the dental follicle (DF), except for the gingiva. In the early developmental stages, the DF surrounds the tooth germ as a sphere and functions to promote tooth eruption. However, the morphological dynamics and factors regulating the differentiation of the DF during root elongation remain largely unknown. Miniature pigs are regarded as a useful experimental animal for modeling in craniofacial research because they are similar to humans with respect to dentition and mandible anatomy. In the present study, we used the third deciduous incisor of miniature pig as the model to investigate the factors influencing DF differentiation during root development. We found that the DF was shaped like a crescent and was located between the root apical and the alveolar bone. The expression levels of WNT5a, β-Catenin, and COL-I gradually increased from the center of the DF (beneath the apical foramen) to the lateral coronal corner, where the DF differentiates into the periodontium. To determine the potential regulatory role of the apical papilla on DF cell differentiation, we co-cultured dental follicle stem cells (DFSCs) with stem cells of the apical papilla (SCAPs). The osteogenesis and fibrogenesis abilities of DFSCs were inhibited when being co-cultured with SCAPs, suggesting that the fate of the DF can be regulated by signals from the apical papilla. The apical papilla may sustain the undifferentiated status of DFSCs before root development finishes. These data yield insight into the interaction between the root apex and surrounding DF tissues in root and periodontium development and shed light on the future study of root regeneration in large mammals. PMID:29511365

Nanomaterials for regulating cancer and stem cell fate

NASA Astrophysics Data System (ADS)

Shah, Birju P.

The realm of nanomedicine has grown exponentially over the past few decades. However, there are several obstacles that need to be overcome, prior to the wide-spread clinical applications of these nanoparticles, such as (i) developing well-defined nanoparticles of varying size, morphology and composition to enable various clinical applications; (ii) overcome various physiological barriers encountered in order to deliver the therapeutics to the target location; and (iii) real-time monitoring of the nano-therapeutics within the human body for tracking their uptake, localization and effect. Hence, this dissertation focuses on developing multimodal nanotechnology-based approaches to overcome the above-mentioned challenges and thus enable regulation of cancer and stem cell fate. The initial part of this dissertation describes the development of multimodal magnetic core-shell nanoparticles (MCNPs), comprised of a highly magnetic core surrounded by a thin gold shell, thus combining magnetic and plasmonic properties. These nanoparticles were utilized for mainly two applications: (i) Magnetically-facilitated delivery of siRNA and plasmid DNA for effective stem cell differentiation and imaging and (ii) Combined hyperthermia and targeted delivery of a mitochondria-targeting peptide for enhancing apoptosis in cancer cells. The following part of this dissertation presents the generation of a multi-functional cyclodextrin-conjugated polymeric delivery platform (known as DexAMs), for co-delivery of anticancer drugs and siRNAs in a target-specific manner to brain tumor cells. This combined delivery of chemotherapeutics and siRNA resulted in a synergistic effect on the apoptosis of brain tumor cells, as compared to the individual treatments. The final part of this thesis presents development of stimuli-responsive uorescence resonance energy transfer (FRET)-based mesoporous silica nanoparticles for real-time monitoring of drug release in cells. The stimuli-responsive behavior of these nanoparticles resulted in change in the FRET signal, thus allowing for real time monitoring of drug release. Taken together, these nanomaterial-based approaches combine therapeutic and imaging modalities within a single nanoplatform and as a result have the potential for regulating cancer and stem cell fate such as proliferation, differentiation and apoptosis as well as allowing for real-time monitoring of these events in a non-invasive manner.

Isolation and expansion of functionally-competent cardiac progenitor cells directly from heart biopsies

PubMed Central

Davis, Darryl R; Kizana, Eddy; Terrovitis, John; Barth, Andreas S.; Zhang, Yiqiang; Smith, Rachel Ruckdeschel; Miake, Junichiro; Marbán, Eduardo

2010-01-01

The adult heart contains reservoirs of progenitor cells that express embryonic and stem cell-related antigens. While these antigenically-purified cells are promising candidates for autologous cell therapy, clinical application is hampered by their limited abundance and tedious isolation methods. Methods that involve an intermediate cardiosphere-forming step have proven successful and are being tested clinically, but it is unclear whether the cardiosphere step is necessary. Accordingly, we investigated the molecular profile and functional benefit of cells that spontaneously emigrate from cardiac tissue in primary culture. Adult Wistar-Kyoto rat hearts were minced, digested and cultured as separate anatomical regions. Loosely-adherent cells that surround the plated tissue were harvested weekly for a total of five harvests. Genetic lineage tracing demonstrated that a small proportion of the direct outgrowth from cardiac samples originates from myocardial cells. This outgrowth contains sub-populations of cells expressing embryonic (SSEA-1) and stem cell-related antigens (c-Kit, abcg2) that varied with time in culture but not with the cardiac chamber of origin. This direct outgrowth, and its expanded progeny, underwent marked in vitro angiogenic/cardiogenic differentiation and cytokine secretion (IGF-1, VGEF). In vivo effects included long-term functional benefits as gauged by MRI following cell injection in a rat model of myocardial infarction. Outgrowth cells afforded equivalent functional benefits to cardiosphere-derived cells, which require more processing steps to manufacture. These results provide the basis for a simplified and efficient process to generate autologous cardiac progenitor cells (and mesenchymal supporting cells) to augment clinically-relevant approaches for myocardial repair. PMID:20211627

Contribution of Adipose Tissue to Development of Cancer

PubMed Central

Cozzo, Alyssa J.; Fuller, Ashley M.; Makowski, Liza

2018-01-01

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose “organ,” and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. PMID:29357128

The RNA-binding protein Musashi-1 is produced in the developing and adult mouse eye.

PubMed

Raji, B; Dansault, A; Leemput, J; de la Houssaye, G; Vieira, V; Kobetz, A; Arbogast, L; Masson, C; Menasche, M; Abitbol, M

2007-08-10

Musashi-1 (Msi1) is an RNA-binding protein produced in various types of stem cells including neural stem/progenitor cells and astroglial progenitor cells in the vertebrate central nervous system. Other RNA-binding proteins such as Pumilio-1, Pumilio-2, Staufen-1, and Staufen-2 have been characterized as potential markers of several types of stem or progenitor cells. We investigated the involvement of Msi1 in mouse eye development and adult mouse eye functions by analyzing the profile of Msi1 production in all ocular structures during development and adulthood. We studied Msi1 production by in situ hybridization and immunohistochemistry of ocular tissue sections and by semi-quantitative RT-PCR and western blot analysis from the embryonic stage of 12.5 days post coitum (E12.5 dpc) when the first retinal ganglion cells (RGCs) begin to appear to the adult stage when all retinal cell types are present. Msi1 mRNA was present at all studied stages of eye development. Msi1 protein was detected in the primitive neuroblastic layer (NbL), the ganglion cell layer (GCL), and in all major differentiated neurons of postnatal developing and adult retinae. During postnatal developing stages, faint diffuse Msi1 protein staining is converted to a more specific distribution once mouse retina is fully differentiated. The most striking result of our study concerns the large amounts of Msi1 protein and mRNA in several unexpected sites of adult mouse eyes including the corneal epithelium and endothelium, stromal keratocytes, progenitor cells of the limbus, equatorial lens stem cells, differentiated lens epithelial cells, and differentiating lens fibers. Msi1 was also found in the pigmented and nonpigmented cells of the ciliary processes, the melanocytes of the ciliary body, the retinal pigment epithelium, differentiated retinal neurons, and most probably in the retinal glial cells such as Müller glial cells, astrocytes, and the oligodendocytes surrounding the axons of the optic nerve. Msi1 expression was detected in the outer plexiform layer, the inner plexiform layer, and the nerve fiber layer of fully differentiated adult retina. We provide here the first demonstration that the RNA-binding protein, Msi1, is produced in mouse eyes from embryonic stages until adulthood. The relationship between the presence of Msi1 in developing ocular compartments and the possible stem/progenitor cell characteristics of these compartments remains unclear. Finally, the expression of Msi1 in several different cell types in the adult eye is extremely intriguing and should lead to further attempts to unravel the role of Msi1 in cellular and subcellular RNA metabolism and in the control of translational processes in adult eye cells particularly in adult neuronal dendrites, axons, and synapses.

The Controversy Surrounding Bone Morphogenetic Proteins in the Spine: A Review of Current Research

PubMed Central

Hustedt, Joshua W.; Blizzard, Daniel J.

2014-01-01

Bone morphogenetic proteins have been in use in spinal surgery since 2002. These proteins are members of the TGF-beta superfamily and guide mesenchymal stem cells to differentiate into osteoblasts to form bone in targeted tissues. Since the first commercial BMP became available in 2002, a host of research has supported BMPs and they have been rapidly incorporated in spinal surgeries in the United States. However, recent controversy has arisen surrounding the ethical conduct of the research supporting the use of BMPs. Yale University Open Data Access (YODA) recently teamed up with Medtronic to offer a meta-analysis of the effectiveness of BMPs in spinal surgery. This review focuses on the history of BMPs and examines the YODA research to guide spine surgeons in their use of BMP in spinal surgery. PMID:25506287

Types of Stem Cells

MedlinePlus

... Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

Reimagining the Role of School Libraries in STEM Education: Creating Hybrid Spaces for Exploration

ERIC Educational Resources Information Center

Subramaniam, Mega M.; Ahn, June; Fleischmann, Kenneth R.; Druin, Allison

2012-01-01

In recent years, many technological interventions have surfaced, such as virtual worlds, games, and digital labs, that aspire to link young people's interest in media technology and social networks to learning about science, technology, engineering, and math (STEM) areas. Despite the tremendous interest surrounding young people and STEM education,…

Effects of Verticillium dahliae infection on stem-end chip defect development in potatoes (Solanum tuberosum L.)

USDA-ARS?s Scientific Manuscript database

Potato chips are America's favorite snack food with annual retail sales of over $6 billion. Stem-end chip defect, which is characterized by discoloration of the vasculature and surrounding tissues at the tuber stem end portion of chips, is an important tuber quality concern for US chip production. T...

miRNA-regulated cancer stem cells: understanding the property and the role of miRNA in carcinogenesis.

PubMed

Chakraborty, Chiranjib; Chin, Kok-Yong; Das, Srijit

2016-10-01

Over the last few years, microRNAs (miRNA)-controlled cancer stem cells have drawn enormous attention. Cancer stem cells are a small population of tumor cells that possess the stem cell property of self-renewal. Recent data shows that miRNA regulates this small population of stem cells. In the present review, we explained different characteristics of cancer stem cells as well as miRNA regulation of self-renewal and differentiation in cancer stem cells. We also described the migration and tumor formation. Finally, we described the different miRNAs that regulate various types of cancer stem cells, such as prostate cancer stem cells, head and neck cancer stem cells, breast cancer stem cells, colorectal cancer stem cells, lung cancer stem cells, gastric cancer stem cells, pancreatic cancer stem cells, etc. Extensive research is needed in order to employ miRNA-based therapeutics to control cancer stem cell population in various cancers in the future.

What is a stem cell?

PubMed

Slack, Jonathan M W

2018-05-15

The historical roots of the stem cell concept are traced with respect to its usage in embryology and in hematology. The modern consensus definition of stem cells, comprising both pluripotent stem cells in culture and tissue-specific stem cells in vivo, is explained and explored. Methods for identifying stem cells are discussed with respect to cell surface markers, telomerase, label retention and transplantability, and properties of the stem cell niche are explored. The CreER method for identifying stem cells in vivo is explained, as is evidence in favor of a stochastic rather than an obligate asymmetric form of cell division. In conclusion, it is found that stem cells do not possess any unique and specific molecular markers; and stem cell behavior depends on the environment of the cell as well as the stem cell's intrinsic qualities. Furthermore, the stochastic mode of division implies that stem cell behavior is a property of a cell population not of an individual cell. In this sense, stem cells do not exist in isolation but only as a part of multicellular system. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches Adult Stem Cells, Tissue Renewal, and Regeneration > Methods and Principles Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells. © 2018 Wiley Periodicals, Inc.

Loss of imprinting of IGF2 and the epigenetic progenitor model of cancer

PubMed Central

Leick, Mark B; Shoff, Christopher J; Wang, Erwin C; Congress, Jaclyn L; Gallicano, G Ian

2012-01-01

Among the hypotheses discussing cancer formation, the cancer stem cell (CSC) theory is one receiving widespread support. One version of this theory states that changes in otherwise healthy cells can cause formation of tumor- initiating cells (TICs), which have the potential to create precancerous stem cells that can lead to CSC formation. These CSCs can be rare, in contrast to their differentiated progeny, which give rise to the vast majority of the tumor mass in most cancers. Loss of imprinting (LOI) of the insulin-like growth factor-2 (IGF2) gene is one change that can produce these TICs via an epigenetic progenitor model of tumorigenesis. While IGF2 usually supports normal cellular growth, LOI of IGF2 may lead to overexpression of the gene and moreover global chromatin instability. This modification has been observed in many forms of cancer, and given the effect of LOI of IGF2 and its role in cancer, detecting a loss of imprinting in this gene could serve as a valuable diagnostic tool. Preclinical data has shown some progress in identifying therapeutic approaches seeking to exploit this relationship. Thus, further research surrounding LOI of IGF2 could lead to increased understanding of several cancer types and enhance therapies against these diseases. PMID:23671798

Synovial Mesenchymal Stem Cells Promote Meniscus Regeneration Augmented by an Autologous Achilles Tendon Graft in a Rat Partial Meniscus Defect Model

PubMed Central

Ozeki, Nobutake; Muneta, Takeshi; Matsuta, Seiya; Koga, Hideyuki; Nakagawa, Yusuke; Mizuno, Mitsuru; Tsuji, Kunikazu; Mabuchi, Yo; Akazawa, Chihiro; Kobayashi, Eiji; Saito, Tomoyuki; Sekiya, Ichiro

2015-01-01

Although meniscus defects and degeneration are strongly correlated with the later development of osteoarthritis, the promise of regenerative medicine strategies is to prevent and/or delay the disease's progression. Meniscal reconstruction has been shown in animal models with tendon grafting and transplantation of mesenchymal stem cells (MSCs); however, these procedures have not shown the same efficacy in clinical studies. Here, our aim was to investigate the ability of tendon grafts pretreated with exogenous synovial-derived MSCs to prevent cartilage degeneration in a rat partial meniscus defect model. We removed the anterior half of the medial meniscus and grafted autologous Achilles tendons with or without a 10-minute pretreatment of the tendon with synovial MSCs. The meniscus and surrounding cartilage were evaluated at 2, 4, and 8 weeks (n = 5). Tendon grafts increased meniscus size irrespective of synovial MSCs. Histological scores for regenerated menisci were better in the tendon + MSC group than in the other two groups at 4 and 8 weeks. Both macroscopic and histological scores for articular cartilage were significantly better in the tendon + MSC group at 8 weeks. Implanted synovial MSCs survived around the grafted tendon and native meniscus integration site by cell tracking assays with luciferase+, LacZ+, DiI+, and/or GFP+ synovial MSCs and/or GFP+ tendons. Flow cytometric analysis showed that transplanted synovial MSCs retained their MSC properties at 7 days and host synovial tissue also contained cells with MSC characteristics. Synovial MSCs promoted meniscus regeneration augmented by autologous Achilles tendon grafts and prevented cartilage degeneration in rats. Stem Cells 2015;33:1927–1938 PMID:25993981

In Vivo Exposure to Inorganic Arsenic Alters Differentiation-Specific Gene Expression of Adipose-Derived Mesenchymal Stem/Stromal Cells in C57BL/6J Mouse Model

PubMed Central

Shearer, Joseph J.; Figueiredo Neto, Manoel; Umbaugh, C. Samuel; Figueiredo, Marxa L.

2017-01-01

Abstract The number of mesenchymal stem cell (MSC) therapeutic modalities has grown in recent years. Adipose-derived mesenchymal stem/stromal cells (ASCs) can be isolated and expanded relatively easily as compared with their bone-marrow counterparts, making them a particularly promising source of MSCs. And although the biological mechanisms surrounding ASCs are actively being investigated, little is known about the effects that in vivo environmental exposures might have on their ability to properly differentiate. Therefore, we hypothesized that ASCs isolated from mice exposed to inorganic arsenic (iAs) would have an altered response towards adipogenic, osteogenic, and/or chondrogenic differentiation. To test this hypothesis, C57BL/6J male mice were provided drinking water containing 0, 300, or 1000 ppb iAs. ASCs were then isolated and differentiated, which was assessed by immunocytochemistry and real-time quantitative PCR (RT-qPCR). Our results showed that total urinary arsenic equilibrated within 1 week of exposure to iAs and was maintained throughout the study. ASCs isolated from each exposure group maintained differentiation capabilities for each lineage. The magnitude of differentiation-specific gene expression, however, appeared to be concentration dependent. For osteogenesis and chondrogenesis, differentiation-specific gene expression decreased, whereas adipogenesis showed a biphasic response with an initial decrease followed by an increase in adipogenic-related gene expression following iAs exposure. These results suggest that the level in which differentiation-specific genes are induced within these stromal cells might be sensitive to environmental contaminants. These findings highlight the need to take into account potential environmental exposures prior to selecting stromal cell donors, so ASCs can achieve optimal efficiency in regenerative therapy applications. PMID:28206643

Ultrasound -Assisted Gene Transfer to Adipose Tissue-Derived Stem/Progenitor Cells (ASCs)

NASA Astrophysics Data System (ADS)

Miyamoto, Yoshitaka; Ueno, Hitomi; Hokari, Rei; Yuan, Wenji; Kuno, Shuichi; Kakimoto, Takashi; Enosawa, Shin; Negishi, Yoichi; Yoshinaka, Kiyoshi; Matsumoto, Yoichiro; Chiba, Toshio; Hayashi, Shuji

2011-09-01

In recent years, multilineage adipose tissue-derived stem cells (ASCs) have become increasingly attractive as a promising source for cell transplantation and regenerative medicine. Particular interest has been expressed in the potential to make tissue stem cells, such as ASCs and marrow stromal cells (MSCs), differentiate by gene transfection. Gene transfection using highly efficient viral vectors such as adeno- and sendai viruses have been developed for this purpose. Sonoporation, or ultrasound (US)-assisted gene transfer, is an alternative gene manipulation technique which employs the creation of a jet stream by ultrasonic microbubble cavitation. Sonoporation using non-viral vectors is expected to be a much safer, although less efficient, tool for prospective clinical gene therapy. In this report, we assessed the efficacy of the sonoporation technique for gene transfer to ASCs. We isolated and cultured adipocyets from mouse adipose tissue. ASCs that have the potential to differentiate with transformation into adipocytes or osteoblasts were obtained. Using the US-assisted system, plasmid DNA containing beta-galactosidase (beta-Gal) and green fluorescent protein (GFP) genes were transferred to the ASCs. For this purpose, a Sonopore 4000 (NEPAGENE Co.) and a Sonazoid (Daiichi Sankyo Co.) instrument were used in combination. ASCs were subjected to US (3.1 MHz, 50% duty cycle, burst rate 2.0 Hz, intensity 1.2 W/cm2, exposure time 30 sec). We observed that the gene was more efficiently transferred with increased concentrations of plasmid DNA (5-150 μg/mL). However, further optimization of the US parameters is required, as the gene transfer efficiency was still relatively low. In conclusion, we herein demonstrate that a gene can be transferred to ASCs using our US-assisted system. In regenerative medicine, this system might resolve the current issues surrounding the use of viral vectors for gene transfer.

Cancer cells enter dormancy after cannibalizing mesenchymal stem/stromal cells (MSCs)

PubMed Central

Bartosh, Thomas J.; Ullah, Mujib; Zeitouni, Suzanne; Beaver, Joshua; Prockop, Darwin J.

2016-01-01

Patients with breast cancer often develop malignant regrowth of residual drug-resistant dormant tumor cells years after primary treatment, a process defined as cancer relapse. Deciphering the causal basis of tumor dormancy therefore has obvious therapeutic significance. Because cancer cell behavior is strongly influenced by stromal cells, particularly the mesenchymal stem/stromal cells (MSCs) that are actively recruited into tumor-associated stroma, we assessed the impact of MSCs on breast cancer cell (BCC) dormancy. Using 3D cocultures to mimic the cellular interactions of an emerging tumor niche, we observed that MSCs sequentially surrounded the BCCs, promoted formation of cancer spheroids, and then were internalized/degraded through a process resembling the well-documented yet ill-defined clinical phenomenon of cancer cell cannibalism. This suspected feeding behavior was less appreciable in the presence of a rho kinase inhibitor and in 2D monolayer cocultures. Notably, cannibalism of MSCs enhanced survival of BCCs deprived of nutrients but suppressed their tumorigenicity, together suggesting the cancer cells entered dormancy. Transcriptome profiles revealed that the resulting BCCs acquired a unique molecular signature enriched in prosurvival factors and tumor suppressors, as well as inflammatory mediators that demarcate the secretome of senescent cells, also referred to as the senescence-associated secretory phenotype. Overall, our results provide intriguing evidence that cancer cells under duress enter dormancy after cannibalizing MSCs. Importantly, our practical 3D coculture model could provide a valuable tool to understand the antitumor activity of MSCs and cell cannibalism further, and therefore open new therapeutic avenues for the prevention of cancer recurrence. PMID:27698134

Cancer cells enter dormancy after cannibalizing mesenchymal stem/stromal cells (MSCs).

PubMed

Bartosh, Thomas J; Ullah, Mujib; Zeitouni, Suzanne; Beaver, Joshua; Prockop, Darwin J

2016-10-18

Patients with breast cancer often develop malignant regrowth of residual drug-resistant dormant tumor cells years after primary treatment, a process defined as cancer relapse. Deciphering the causal basis of tumor dormancy therefore has obvious therapeutic significance. Because cancer cell behavior is strongly influenced by stromal cells, particularly the mesenchymal stem/stromal cells (MSCs) that are actively recruited into tumor-associated stroma, we assessed the impact of MSCs on breast cancer cell (BCC) dormancy. Using 3D cocultures to mimic the cellular interactions of an emerging tumor niche, we observed that MSCs sequentially surrounded the BCCs, promoted formation of cancer spheroids, and then were internalized/degraded through a process resembling the well-documented yet ill-defined clinical phenomenon of cancer cell cannibalism. This suspected feeding behavior was less appreciable in the presence of a rho kinase inhibitor and in 2D monolayer cocultures. Notably, cannibalism of MSCs enhanced survival of BCCs deprived of nutrients but suppressed their tumorigenicity, together suggesting the cancer cells entered dormancy. Transcriptome profiles revealed that the resulting BCCs acquired a unique molecular signature enriched in prosurvival factors and tumor suppressors, as well as inflammatory mediators that demarcate the secretome of senescent cells, also referred to as the senescence-associated secretory phenotype. Overall, our results provide intriguing evidence that cancer cells under duress enter dormancy after cannibalizing MSCs. Importantly, our practical 3D coculture model could provide a valuable tool to understand the antitumor activity of MSCs and cell cannibalism further, and therefore open new therapeutic avenues for the prevention of cancer recurrence.

Differential marker expression by cultures rich in mesenchymal stem cells

PubMed Central

2013-01-01

Background Mesenchymal stem cells have properties that make them amenable to therapeutic use. However, the acceptance of mesenchymal stem cells in clinical practice requires standardized techniques for their specific isolation. To date, there are no conclusive marker (s) for the exclusive isolation of mesenchymal stem cells. Our aim was to identify markers differentially expressed between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. We compared and contrasted the phenotype of tissue cultures in which mesenchymal stem cells are rich and rare. By initially assessing mesenchymal stem cell differentiation, we established that bone marrow and breast adipose cultures are rich in mesenchymal stem cells while, in our hands, foreskin fibroblast and olfactory tissue cultures contain rare mesenchymal stem cells. In particular, olfactory tissue cells represent non-stem cell mesenchymal cells. Subsequently, the phenotype of the tissue cultures were thoroughly assessed using immuno-fluorescence, flow-cytometry, proteomics, antibody arrays and qPCR. Results Our analysis revealed that all tissue cultures, regardless of differentiation potential, demonstrated remarkably similar phenotypes. Importantly, it was also observed that common mesenchymal stem cell markers, and fibroblast-associated markers, do not discriminate between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. Examination and comparison of the phenotypes of mesenchymal stem cell and non-stem cell mesenchymal cell cultures revealed three differentially expressed markers – CD24, CD108 and CD40. Conclusion We indicate the importance of establishing differential marker expression between mesenchymal stem cells and non-stem cell mesenchymal cells in order to determine stem cell specific markers. PMID:24304471

A Novel Method for Isolation of Pluripotent Stem Cells from Human Umbilical Cord Blood.

PubMed

Monti, Manuela; Imberti, Barbara; Bianchi, Niccolò; Pezzotta, Anna; Morigi, Marina; Del Fante, Claudia; Redi, Carlo Alberto; Perotti, Cesare

2017-09-01

Very small embryonic-like cells (VSELs) are a population of very rare pluripotent stem cells isolated in adult murine bone marrow and many other tissues and organs, including umbilical cord blood (UCB). VSEL existence is still not universally accepted by the scientific community, so for this purpose, we sought to investigate whether presumptive VSELs (pVSELs) could be isolated from human UCB with an improved protocol based on the isolation of enriched progenitor cells by depletion of nonprogenitor cells with magnetic separation. Progenitor cells, likely including VSELs, cultured with retinoic acid were able to form dense colonies and cystic embryoid bodies and to differentiate toward the ecto-meso-endoderm lineages as shown by the positivity to specific markers. VSEL differentiative potential toward mesodermal lineage was further demonstrated in vitro upon exposure to an established inductive protocol, which induced the acquisition of renal progenitor cell phenotype. VSEL-derived renal progenitors showed regenerative potential in a cisplatin model of acute kidney injury by restoring renal function and tubular structure through induction of proliferation of endogenous renal cells. The data presented here foster the great debate that surrounds VSELs and, more in general, the existence of cells endowed with pluripotent features in adult tissues. In fact, the possibility to find and isolate subpopulations of cells that fully fit all the criteria utilized to define pluripotency remains, nowadays, almost unproven. Thus, efforts to better characterize the phenotype of these intriguing cells are crucial to understand their possible applications for regenerative and precision medicine purposes.

Specialized mouse embryonic stem cells for studying vascular development.

PubMed

Glaser, Drew E; Burns, Andrew B; Hatano, Rachel; Medrzycki, Magdalena; Fan, Yuhong; McCloskey, Kara E

2014-01-01

Vascular progenitor cells are desirable in a variety of therapeutic strategies; however, the lineage commitment of endothelial and smooth muscle cell from a common progenitor is not well-understood. Here, we report the generation of the first dual reporter mouse embryonic stem cell (mESC) lines designed to facilitate the study of vascular endothelial and smooth muscle development in vitro. These mESC lines express green fluorescent protein (GFP) under the endothelial promoter, Tie-2, and Discomsoma sp. red fluorescent protein (RFP) under the promoter for alpha-smooth muscle actin (α-SMA). The lines were then characterized for morphology, marker expression, and pluripotency. The mESC colonies were found to exhibit dome-shaped morphology, alkaline phosphotase activity, as well as expression of Oct 3/4 and stage-specific embryonic antigen-1. The mESC colonies were also found to display normal karyotypes and are able to generate cells from all three germ layers, verifying pluripotency. Tissue staining confirmed the coexpression of VE (vascular endothelial)-cadherin with the Tie-2 GFP+ expression on endothelial structures and smooth muscle myosin heavy chain with the α-SMA RFP+ smooth muscle cells. Lastly, it was verified that the developing mESC do express Tie-2 GFP+ and α-SMA RFP+ cells during differentiation and that the GFP+ cells colocalize with the vascular-like structures surrounded by α-SMA-RFP cells. These dual reporter vascular-specific mESC permit visualization and cell tracking of individual endothelial and smooth muscle cells over time and in multiple dimensions, a powerful new tool for studying vascular development in real time.

Learn About Stem Cells

MedlinePlus

... Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... Home > Learn About Stem Cells > Stem Cell Basics Cells in the human body The human body comprises ...

Controlling Cell Function with Geometry

NASA Astrophysics Data System (ADS)

Mrksich, Milan

2012-02-01

This presentation will describe the use of patterned substrates to control cell shape with examples that illustrate the ways in which cell shape can regulate cell function. Most cells are adherent and must attach to and spread on a surface in order to survive, proliferate and function. In tissue, this surface is the extracellular matrix (ECM), an insoluble scaffold formed by the assembly of several large proteins---including fibronectin, the laminins and collagens and others---but in the laboratory, the surface is prepared by adsorbing protein to glass slides. To pattern cells, gold-coated slides are patterned with microcontact printing to create geometric features that promote cell attachment and that are surrounded by inert regions. Cells attach to these substrates and spread to adopt the shape defined by the underlying pattern and remain stable in culture for several days. Examples will be described that used a series of shapes to reveal the relationship between the shape of the cell and the structure of its cytoskeleton. These geometric cues were used to control cell polarity and the tension, or contractility, present in the cytoskeleton. These rules were further used to control the shapes of mesenchymal stem cells and in turn to control the differentiation of these cells into specialized cell types. For example, stem cells that were patterned into a ``star'' shape preferentially differentiated into bone cells whereas those that were patterned into a ``flower'' shape preferred a fat cell fate. These influences of shape on differentiation depend on the mechanical properties of the cytoskeleton. These examples, and others, reveal that shape is an important cue that informs cell function and that can be combined with the more common soluble cues to direct and study cell function.

Knockout-Rescue Embryonic Stem Cell-Derived Mouse Reveals Circadian-Period Control by Quality and Quantity of CRY1.

PubMed

Ode, Koji L; Ukai, Hideki; Susaki, Etsuo A; Narumi, Ryohei; Matsumoto, Katsuhiko; Hara, Junko; Koide, Naoshi; Abe, Takaya; Kanemaki, Masato T; Kiyonari, Hiroshi; Ueda, Hiroki R

2017-01-05

To conduct comprehensive characterization of molecular properties in organisms, we established an efficient method to produce knockout (KO)-rescue mice within a single generation. We applied this method to produce 20 strains of almost completely embryonic stem cell (ESC)-derived mice ("ES mice") rescued with wild-type and mutant Cry1 gene under a Cry1 -/- :Cry2 -/- background. A series of both phosphorylation-mimetic and non-phosphorylation-mimetic CRY1 mutants revealed that multisite phosphorylation of CRY1 can serve as a cumulative timer in the mammalian circadian clock. KO-rescue ES mice also revealed that CRY1-PER2 interaction confers a robust circadian rhythmicity in mice. Surprisingly, in contrast to theoretical predictions from canonical transcription/translation feedback loops, the residues surrounding the flexible P loop and C-lid domains of CRY1 determine circadian period without changing the degradation rate of CRY1. These results suggest that CRY1 determines circadian period through both its degradation-dependent and -independent pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Erythroid differentiation of human induced pluripotent stem cells is independent of donor cell type of origin.

PubMed

Dorn, Isabel; Klich, Katharina; Arauzo-Bravo, Marcos J; Radstaak, Martina; Santourlidis, Simeon; Ghanjati, Foued; Radke, Teja F; Psathaki, Olympia E; Hargus, Gunnar; Kramer, Jan; Einhaus, Martin; Kim, Jeong Beom; Kögler, Gesine; Wernet, Peter; Schöler, Hans R; Schlenke, Peter; Zaehres, Holm

2015-01-01

Epigenetic memory in induced pluripotent stem cells, which is related to the somatic cell type of origin of the stem cells, might lead to variations in the differentiation capacities of the pluripotent stem cells. In this context, induced pluripotent stem cells from human CD34(+) hematopoietic stem cells might be more suitable for hematopoietic differentiation than the commonly used fibroblast-derived induced pluripotent stem cells. To investigate the influence of an epigenetic memory on the ex vivo expansion of induced pluripotent stem cells into erythroid cells, we compared induced pluripotent stem cells from human neural stem cells and human cord blood-derived CD34(+) hematopoietic stem cells and evaluated their potential for differentiation into hematopoietic progenitor and mature red blood cells. Although genome-wide DNA methylation profiling at all promoter regions demonstrates that the epigenetic memory of induced pluripotent stem cells is influenced by the somatic cell type of origin of the stem cells, we found a similar hematopoietic induction potential and erythroid differentiation pattern of induced pluripotent stem cells of different somatic cell origin. All human induced pluripotent stem cell lines showed terminal maturation into normoblasts and enucleated reticulocytes, producing predominantly fetal hemoglobin. Differences were only observed in the growth rate of erythroid cells, which was slightly higher in the induced pluripotent stem cells derived from CD34(+) hematopoietic stem cells. More detailed methylation analysis of the hematopoietic and erythroid promoters identified similar CpG methylation levels in the induced pluripotent stem cell lines derived from CD34(+) cells and those derived from neural stem cells, which confirms their comparable erythroid differentiation potential. Copyright© Ferrata Storti Foundation.

[Progress in stem cells and regenerative medicine].

PubMed

Wang, Libin; Zhu, He; Hao, Jie; Zhou, Qi

2015-06-01

Stem cells have the ability to differentiate into all types of cells in the body and therefore have great application potential in regenerative medicine, in vitro disease modelling and drug screening. In recent years, stem cell technology has made great progress, and induced pluripotent stem cell technology revolutionizes the whole stem cell field. At the same time, stem cell research in our country has also achieved great progress and becomes an indispensable power in the worldwide stem cell research field. This review mainly focuses on the research progress in stem cells and regenerative medicine in our country since the advent of induced pluripotent stem cell technology, including induced pluripotent stem cells, transdifferentiation, haploid stem cells, and new gene editing tools.

Application of Graphene Based Nanotechnology in Stem Cells Research.

PubMed

Hu, Shanshan; Zeng, Yongxiang; Yang, Shuying; Qin, Han; Cai, He; Wang, Jian

2015-09-01

The past several years have witnessed significant advances in stem cell therapy, tissue engineering and regenerative medicine. Graphene, with its unique properties such as high electrical conductivity, elasticity and good molecule absorption, have potential for creating the next generation of biomaterials. This review summarizes the interrelationship between graphene and stem cells. The analysis of graphene when applied on mesenchymal stem cells, neural stem cells, induced pluripotent stem cells, embryonic stem cells, periodontal ligament stem cells, human adipose-derived stem cells and cancer stem cells, and how graphene influences cell behavior and differentiation are discussed in details.

BAM 1 and RECEPTOR-LIKE PROTEIN KINASE 2 constitute a signaling pathway and modulate CLE peptide-triggered growth inhibition in Arabidopsis root.

PubMed

Shimizu, Noriko; Ishida, Takashi; Yamada, Masashi; Shigenobu, Shuji; Tabata, Ryo; Kinoshita, Atsuko; Yamaguchi, Katsushi; Hasebe, Mitsuyasu; Mitsumasu, Kanako; Sawa, Shinichiro

2015-12-01

Ligand receptor-based signaling is a means of cell-to-cell communication for coordinating developmental and physiological processes in multicellular organisms. In plants, cell-producing meristems utilize this signaling to regulate their activities and ensure for proper development. Shoot and root systems share common requirements for carrying out this process; however, its molecular basis is largely unclear. It has been suggested that synthetic CLV3/EMBRYO SURROUNDING REGION (CLE) peptide shrinks the root meristem through the actions of CLAVATA2 (CLV2) and the RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2) pathway in Arabidopsis thaliana. Our genetic screening for mutations that resist CLE peptide signaling in roots determined that BAM1, which is a member of the leucine-rich repeat receptor-like kinase (LRR-RLK) family, is also involved in this pathway. BAM1 is preferentially expressed in the root tip, including the quiescent center and its surrounding stem cells. Our genetic analysis revealed that BAM1 functions together with RPK2. Using coimmunoprecipitation assay, we showed that BAM1 is capable of forming heteromeric complexes with RPK2. These findings suggest that the BAM1 and RPK2 receptors constitute a signaling pathway that modulates cell proliferation in the root meristem and that related molecules are employed in root and shoot meristems. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

A revisionist history of adult marrow stem cell biology or 'they forgot about the discard'.

PubMed

Quesenberry, P; Goldberg, L

2017-08-01

The adult marrow hematopoietic stem cell biology has largely been based on studies of highly purified stem cells. This is unfortunate because during the stem cell purification the great bulk of stem cells are discarded. These cells are actively proliferating. The final purified stem cell is dormant and not representative of the whole stem cell compartment. Thus, a large number of studies on the cellular characteristics, regulators and molecular details of stem cells have been carried on out of non-represented cells. Niche studies have largely pursued using these purified stem cells and these are largely un-interpretable. Other considerations include the distinction between baseline and transplant stem cells and the modulation of stem cell phenotype by extracellular vesicles, to cite a non-inclusive list. Work needs to proceed on characterizing the true stem cell population.

Neuromast hair cells retain the capacity of regeneration during heavy metal exposure.

PubMed

Montalbano, G; Capillo, G; Laurà, R; Abbate, F; Levanti, M; Guerrera, M C; Ciriaco, E; Germanà, A

2018-07-01

The neuromast is the morphological unit of the lateral line of fishes and is composed of a cluster of central sensory cells (hair cells) surrounded by support and mantle cells. Heavy metals exposure leads to disruption of hair cells within the neuromast. It is well known that the zebrafish has the ability to regenerate the hair cells after damage caused by toxicants. The process of regeneration depends on proliferation, differentiation and cellular migration of sensory and non-sensory progenitor cells. Therefore, our study was made in order to identify which cellular types are involved in the complex process of regeneration during heavy metals exposure. For this purpose, adult zebrafish were exposed to various heavy metals (Arsenic, cadmium and zinc) for 72h. After acute (24h) exposure, immunohistochemical localization of S100 (a specific marker for hair cells) in the neuromasts highlighted the hair cells loss. The immunoreaction for Sox2 (a specific marker for stem cells), at the same time, was observed in the support and mantle cells, after exposure to arsenic and cadmium, while only in the support cells after exposure to zinc. After chronic (72h) exposure the hair cells were regenerated, showing an immunoreaction for S100 protein. At the same exposure time to the three metals, a Sox2 immunoreaction was expressed in support and mantle cells. Our results showed for the first time the regenerative capacity of hair cells, not only after, but also during exposure to heavy metals, demonstrated by the presence of different stem cells that can diversify in hair cells. Copyright © 2018 Elsevier GmbH. All rights reserved.

The potential role of telocytes in Tissue Engineering and Regenerative Medicine.

PubMed

Boos, Anja M; Weigand, Annika; Brodbeck, Rebekka; Beier, Justus P; Arkudas, Andreas; Horch, Raymund E

2016-07-01

Research and ideas for potential applications in the field of Tissue Engineering (TE) and Regenerative Medicine (RM) have been constantly increasing over recent years, basically driven by the fundamental human dream of repairing and regenerating lost tissue and organ functions. The basic idea of TE is to combine cells with putative stem cell properties with extracellular matrix components, growth factors and supporting matrices to achieve independently growing tissue. As a side effect, in the past years, more insights have been gained into cell-cell interaction and how to manipulate cell behavior. However, to date the ideal cell source has still to be found. Apart from commonly known various stem cell sources, telocytes (TC) have recently attracted increasing attention because they might play a potential role for TE and RM. It becomes increasingly evident that TC provide a regenerative potential and act in cellular communication through their network-forming telopodes. While TE in vitro experiments can be the first step, the key for elucidating their regenerative role will be the investigation of the interaction of TC with the surrounding tissue. For later clinical applications further steps have to include an upscaling process of vascularization of engineered tissue. Arteriovenous loop models to vascularize such constructs provide an ideal platform for preclinical testing of future therapeutic concepts in RM. The following review article should give an overview of what is known so far about the potential role of TC in TE and RM. Copyright © 2016 Elsevier Ltd. All rights reserved.

Perspectives on stem cell therapy for cardiac regeneration. Advances and challenges.

PubMed

Choi, Sung Hyun; Jung, Seok Yun; Kwon, Sang-Mo; Baek, Sang Hong

2012-01-01

Ischemic heart disease (IHD) accelerates cardiomyocyte loss, but the developing stem cell research could be useful for regenerating a variety of tissue cells, including cardiomyocytes. Diverse sources of stem cells for IHD have been reported, including embryonic stem cells, induced pluripotent stem cells, skeletal myoblasts, bone marrow-derived stem cells, mesenchymal stem cells, and cardiac stem cells. However, stem cells have unique advantages and disadvantages for cardiac tissue regeneration, which are important considerations in determining the specific cells for improving cell survival and long-term engraftment after transplantation. Additionally, the dosage and administration method of stem cells need to be standardized to increase stability and efficacy for clinical applications. Accordingly, this review presents a summary of the stem cell therapies that have been studied for cardiac regeneration thus far, and discusses the direction of future cardiac regeneration research for stem cells.

Stem Cells

MedlinePlus

Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

Preparation of poly(ethylene glycol)/polylactide hybrid fibrous scaffolds for bone tissue engineering.

PubMed

Ni, PeiYan; Fu, ShaoZhi; Fan, Min; Guo, Gang; Shi, Shuai; Peng, JinRong; Luo, Feng; Qian, ZhiYong

2011-01-01

Polylactide (PLA) electrospun fibers have been reported as a scaffold for bone tissue engineering application, however, the great hydrophobicity limits its broad application. In this study, the hybrid amphiphilic poly(ethylene glycol) (PEG)/hydrophobic PLA fibrous scaffolds exhibited improved morphology with regular and continuous fibers compared to corresponding blank PLA fiber mats. The prepared PEG/PLA fibrous scaffolds favored mesenchymal stem cell (MSC) attachment and proliferation by providing an interconnected porous extracellular environment. Meanwhile, MSCs can penetrate into the fibrous scaffold through the interstitial pores and integrate well with the surrounding fibers, which is very important for favorable application in tissue engineering. More importantly, the electrospun hybrid PEG/PLA fibrous scaffolds can enhance MSCs to differentiate into bone-associated cells by comprehensively evaluating the representative markers of the osteogenic procedure with messenger ribonucleic acid quantitation and protein analysis. MSCs on the PEG/PLA fibrous scaffolds presented better differentiation potential with higher messenger ribonucleic acid expression of the earliest osteogenic marker Cbfa-1 and mid-stage osteogenic marker Col I. The significantly higher alkaline phosphatase activity of the PEG/PLA fibrous scaffolds indicated that these can enhance the differentiation of MSCs into osteoblast-like cells. Furthermore, the higher messenger ribonucleic acid level of the late osteogenic differentiation markers OCN (osteocalcin) and OPN (osteopontin), accompanied by the positive Alizarin red S staining, showed better maturation of osteogenic induction on the PEG/PLA fibrous scaffolds at the mineralization stage of differentiation. After transplantation into the thigh muscle pouches of rats, and evaluating the inflammatory cells surrounding the scaffolds and the physiological characteristics of the surrounding tissues, the PEG/PLA scaffolds presented good biocompatibility. Based on the good cellular response and excellent osteogenic potential in vitro, as well as the biocompatibility with the surrounding tissues in vivo, the electrospun PEG/PLA fibrous scaffolds could be one of the most promising candidates in bone tissue engineering.

The Role of Integrin α6 (CD49f) in Stem Cells: More than a Conserved Biomarker.

PubMed

Krebsbach, Paul H; Villa-Diaz, Luis G

2017-08-01

Stem cells have the capacity for self-renewal and differentiation into specialized cells that form and repopulated all tissues and organs, from conception to adult life. Depending on their capacity for differentiation, stem cells are classified as totipotent (ie, zygote), pluripotent (ie, embryonic stem cells), multipotent (ie, neuronal stem cells, hematopoietic stem cells, epithelial stem cells, etc.), and unipotent (ie, spermatogonial stem cells). Adult or tissue-specific stem cells reside in specific niches located in, or nearby, their organ or tissue of origin. There, they have microenvironmental support to remain quiescent, to proliferate as undifferentiated cells (self-renewal), and to differentiate into progenitors or terminally differentiated cells that migrate from the niche to perform specialized functions. The presence of proteins at the cell surface is often used to identify, classify, and isolate stem cells. Among the diverse groups of cell surface proteins used for these purposes, integrin α6, also known as CD49f, may be the only biomarker commonly found in more than 30 different populations of stem cells, including some cancer stem cells. This broad expression among stem cell populations indicates that integrin α6 may play an important and conserved role in stem cell biology, which is reaffirmed by recent demonstrations of its role maintaining self-renewal of pluripotent stem cells and breast and glioblastoma cancer stem cells. Therefore, this review intends to highlight and synthesize new findings on the importance of integrin α6 in stem cell biology.

Modulation of the tumor microenvironment by Epstein-Barr virus latent membrane protein 1 in nasopharyngeal carcinoma.

PubMed

Yoshizaki, Tomokazu; Kondo, Satoru; Endo, Kazuhira; Nakanishi, Yosuke; Aga, Mitsuharu; Kobayashi, Eiji; Hirai, Nobuyuki; Sugimoto, Hisashi; Hatano, Miyako; Ueno, Takayoshi; Ishikawa, Kazuya; Wakisaka, Naohiro

2018-02-01

Latent membrane protein 1 (LMP1) is a primary oncogene encoded by the Epstein-Barr virus, and various portions of LMP1 are detected in nasopharyngeal carcinoma (NPC) tumor cells. LMP1 has been extensively studied since the discovery of its transforming property in 1985. LMP1 promotes cancer cell growth during NPC development and facilitates the interaction of cancer cells with surrounding stromal cells for invasion, angiogenesis, and immune modulation. LMP1 is detected in 100% of pre-invasive NPC tumors and in approximately 50% of advanced NPC tumors. Moreover, a small population of LMP1-expressing cells in advanced NPC tumor tissue is proposed to orchestrate NPC tumor tissue maintenance and development through cancer stem cells and progenitor cells. Recent studies suggest that LMP1 activity shifts according to tumor development stage, but it still has a pivotal role during all stages of NPC development. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

What Is Trophoblast? A Combination of Criteria Define Human First-Trimester Trophoblast

PubMed Central

Lee, Cheryl Q.E.; Gardner, Lucy; Turco, Margherita; Zhao, Nancy; Murray, Matthew J.; Coleman, Nicholas; Rossant, Janet; Hemberger, Myriam; Moffett, Ashley

2016-01-01

Summary Controversy surrounds reports describing the derivation of human trophoblast cells from placentas and embryonic stem cells (ESC), partly due to the difficulty in identifying markers that define cells as belonging to the trophoblast lineage. We have selected criteria that are characteristic of primary first-trimester trophoblast: a set of protein markers, HLA class I profile, methylation of ELF5, and expression of microRNAs (miRNAs) from the chromosome 19 miRNA cluster (C19MC). We tested these criteria on cells previously reported to show some phenotypic characteristics of trophoblast: bone morphogenetic protein (BMP)-treated human ESC and 2102Ep, an embryonal carcinoma cell line. Both cell types only show some, but not all, of the four trophoblast criteria. Thus, BMP-treated human ESC have not fully differentiated to trophoblast. Our study identifies a robust panel, including both protein and non-protein-coding markers that, in combination, can be used to reliably define cells as characteristic of early trophoblast. PMID:26862703

Drosophila's contribution to stem cell research.

PubMed

Singh, Gyanesh

2015-01-01

The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila.

Drosophila's contribution to stem cell research

PubMed Central

Singh, Gyanesh

2016-01-01

The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila. PMID:26180635

Mesenchymal stem cells derived from normal gingival tissue inhibit the proliferation of oral cancer cells in vitro and in vivo.

PubMed

Ji, Xiaoli; Zhang, Zhihui; Han, Ying; Song, Jiangyuan; Xu, Xiangliang; Jin, Jianqiu; Su, Sha; Mu, Dongdong; Liu, Xiaodan; Xu, Si; Cui, Hongwei; Zhao, Zhongfang; Wang, Yixiang; Liu, Hongwei

2016-11-01

The interplay between tumor cells and mesenchymal stem cells (MSCs) within tumor microenvironment plays a significant role in tumor development, and thus might be exploited for therapeutic intervention. In this study, we isolated MSCs from normal gingival tissue (GMSCs), and detected the effect of GMSCs on oral cancer cells via direct co-culture and indirect co-culture systems. The cell proliferation assay of direct co-culture showed that GMSCs could inhibit the growth of oral cancer cells. Conditioned medium derived from GMSCs (GMSCs-CM) also exerted an anticancer effect, which indicates that soluble factors in GMSCs-CM played a dominant role in GMSCs-induced cancer cell growth inhibition. To investigate the mechanism, we performed apoptosis assay by flow cytometry, and confirmed that cancer cell apoptosis induced by GMSCs could be a reason for the effect of GMSCs on the growth of oral cancer cells. Western blotting also confirmed that GMSCs could upregulate expression of pro-apoptotic genes including p-JNK, cleaved PARP, cleaved caspase-3, Bax expression and downregulate proliferation- and anti-apoptosis-related gene expression such as p-ERK1/2, Bcl-2, CDK4, cyclin D1, PCNA and survivin. Importantly, the inhibitory effect of GMSCs on cancer cells can partially be restored by blockade of JNK pathway. Moreover, animal studies showed that GMSCs exerted an anticancer effect after oral cancer cells and GMSCs were co-injected with oral cancer cells. Taken together, our data suggest that GMSCs can suppress oral cancer cell growth in vitro and in vivo via altering the surrounding microenvironment of oral cancer cells, which indicates that GMSCs have a potential use in the management of oral dysplasia and oral cancer in future.

Optical cell cleaning with NIR femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Uchugonova, Aisada; Breunig, Hans Georg; Batista, Ana; König, Karsten

2015-03-01

Femtosecond laser microscopes have been used as both micro and nanosurgery tools. The optical knock-out of undesired cells in multiplex cell clusters shall be further reported on in this study. Femtosecond laser-induced cell death is beneficial due to the reduced collateral side effects and therefore can be used to selectively destroy target cells within monolayers, as well as within 3D tissues, all the while preserving cells of interest. This is an important characteristic for the application in stem cell research and cancer treatment. Non-precise damage compromises the viability of neighboring cells by inducing side effects such as stress to the cells surrounding the target due to the changes in the microenvironment, resulting from both the laser and laser-exposed cells. In this study, optimum laser parameters for optical cleaning by isolating single cells and cell colonies are exploited through the use of automated software control. Physiological equilibrium and cellular responses to the laser induced damages are also investigated. Cell death dependence on laser focus, determination and selectivity of intensity/dosage, controllable damage and cell recovery mechanisms are discussed.

Current overview on dental stem cells applications in regenerative dentistry.

PubMed

Bansal, Ramta; Jain, Aditya

2015-01-01

Teeth are the most natural, noninvasive source of stem cells. Dental stem cells, which are easy, convenient, and affordable to collect, hold promise for a range of very potential therapeutic applications. We have reviewed the ever-growing literature on dental stem cells archived in Medline using the following key words: Regenerative dentistry, dental stem cells, dental stem cells banking, and stem cells from human exfoliated deciduous teeth. Relevant articles covering topics related to dental stem cells were shortlisted and the facts are compiled. The objective of this review article is to discuss the history of stem cells, different stem cells relevant for dentistry, their isolation approaches, collection, and preservation of dental stem cells along with the current status of dental and medical applications.

Flow environment and matrix structure interact to determine spatial competition in Pseudomonas aeruginosa biofilms.

PubMed

Nadell, Carey D; Ricaurte, Deirdre; Yan, Jing; Drescher, Knut; Bassler, Bonnie L

2017-01-13

Bacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics in Pseudomonas aeruginosa biofilms. Irrespective of initial frequency, in competition with matrix mutants, wild-type cells always increase in relative abundance in planar microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles - which are common in natural environments - wild-type matrix-producing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero shear that allow matrix mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments.

Peptide Signaling in Plant Development

PubMed Central

Katsir, Leron; Davies, Kelli A.; Bergmann, Dominique C.; Laux, Thomas

2011-01-01

Cell-to-cell communication is integral to the evolution of multicellularity. In plant development, peptide signals relay information coordinating cell proliferation and differentiation. These peptides are often encoded by gene families and bind to corresponding families of receptors. The precise spatiotemporal expression of signals and their cognate receptors underlies developmental patterning, and expressional and biochemical changes over evolutionary time have likely contributed to the refinement and complexity of developmental programs. Here, we discuss two major plant peptide families which have central roles in plant development: the CLAVATA3/ENDOSPERM SURROUNDING REGION (CLE) peptide family and the EPIDERMAL PATTERNING FACTOR (EPF) family. We discuss how specialization has enabled the CLE peptides to modulate stem cell differentiation in various tissue types, and how differing activities of EPF peptides precisely regulate the stomatal developmental program, and we examine the contributions of these peptide families to plant development from an evolutionary perspective. PMID:21549958

Connexins: Intercellular Signal Transmitters in Lymphohematopoietic Tissues.

PubMed

González-Nieto, Daniel; Chang, Kyung-Hee; Fasciani, Ilaria; Nayak, Ramesh; Fernandez-García, Laura; Barrio, Luis C; Cancelas, José A

2015-01-01

Life-long hematopoietic demands are met by a pool of hematopoietic stem cells (HSC) with self-renewal and multipotential differentiation ability. Humoral and paracrine signals from the bone marrow (BM) hematopoietic microenvironment control HSC activity. Cell-to-cell communication through connexin (Cx) containing gap junctions (GJs) allows pluricellular coordination and synchronization through transfer of small molecules with messenger activity. Hematopoietic and surrounding nonhematopoietic cells communicate each other through GJs, which regulate fetal and postnatal HSC content and function in hematopoietic tissues. Traffic of HSC between peripheral blood and BM is also dependent on Cx proteins. Cx mutations are associated with human disease and hematopoietic dysfunction and Cx signaling may represent a target for therapeutic intervention. In this review, we illustrate and highlight the importance of Cxs in the regulation of hematopoietic homeostasis under normal and pathological conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

The longest telomeres: a general signature of adult stem cell compartments

PubMed Central

Flores, Ignacio; Canela, Andres; Vera, Elsa; Tejera, Agueda; Cotsarelis, George; Blasco, María A.

2008-01-01

Identification of adult stem cells and their location (niches) is of great relevance for regenerative medicine. However, stem cell niches are still poorly defined in most adult tissues. Here, we show that the longest telomeres are a general feature of adult stem cell compartments. Using confocal telomere quantitative fluorescence in situ hybridization (telomapping), we find gradients of telomere length within tissues, with the longest telomeres mapping to the known stem cell compartments. In mouse hair follicles, we show that cells with the longest telomeres map to the known stem cell compartments, colocalize with stem cell markers, and behave as stem cells upon treatment with mitogenic stimuli. Using K15-EGFP reporter mice, which mark hair follicle stem cells, we show that GFP-positive cells have the longest telomeres. The stem cell compartments in small intestine, testis, cornea, and brain of the mouse are also enriched in cells with the longest telomeres. This constitutes the description of a novel general property of adult stem cell compartments. Finally, we make the novel finding that telomeres shorten with age in different mouse stem cell compartments, which parallels a decline in stem cell functionality, suggesting that telomere loss may contribute to stem cell dysfunction with age. PMID:18283121

Evaluation of the immunogenicity of human iPS cell-derived neural stem/progenitor cells in vitro.

PubMed

Ozaki, Masahiro; Iwanami, Akio; Nagoshi, Narihito; Kohyama, Jun; Itakura, Go; Iwai, Hiroki; Nishimura, Soraya; Nishiyama, Yuichiro; Kawabata, Soya; Sugai, Keiko; Iida, Tsuyoshi; Matsubayashi, Kohei; Isoda, Miho; Kashiwagi, Rei; Toyama, Yoshiaki; Matsumoto, Morio; Okano, Hideyuki; Nakamura, Masaya

2017-03-01

To achieve the goal of a first-in-human trial for human induced pluripotent stem cell (hiPSC)-based transplantation for the treatment of various diseases, allogeneic human leukocyte antigen (HLA)-matched hiPSC cell banks represent a realistic tool from the perspective of quality control and cost performance. Furthermore, considering the limited therapeutic time-window for acute injuries, including neurotraumatic injuries, an iPS cell bank is of potential interest. However, due to the relatively immunoprivileged environment of the central nervous system, it is unclear whether HLA matching is required in hiPSC-derived neural stem/progenitor cell (hiPSC-NS/PC) transplantation for the treatment of neurodegenerative diseases and neurotraumatic injuries. In this study, we evaluated the significance of HLA matching in hiPSC-NS/PC transplantation by performing modified mixed lymphocyte reaction (MLR) assays with hiPSC-NS/PCs. Compared to fetus-derived NS/PCs, the expression levels of human leukocyte antigen-antigen D related (HLA-DR) and co-stimulatory molecules on hiPSC-NS/PCs were significantly low, even with the addition of tumor necrosis factor-α (TNFα) and/or interferon-γ (IFNγ) to mimic the inflammatory environment surrounding transplanted hiPSC-NS/PCs in injured tissues. Interestingly, both the allogeneic HLA-matched and the HLA-mismatched responses were similarly low in the modified MLR assay. Furthermore, the autologous response was also similar to the allogeneic response. hiPSC-NS/PCs suppressed the proliferative responses of allogeneic HLA-mismatched peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. Thus, the low antigen-presenting function and immunosuppressive effects of hiPSC-NS/PCs result in a depressed immune response, even in an allogeneic HLA-mismatched setting. It is crucial to verify whether these in vitro results are reproducible in a clinical setting. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Epigenetic therapy potential of suberoylanilide hydroxamic acid on invasive human non-small cell lung cancer cells.

PubMed

Zhang, Shirong; Wu, Kan; Feng, Jianguo; Wu, Zhibing; Deng, Qinghua; Guo, Chao; Xia, Bing; Zhang, Jing; Huang, Haixiu; Zhu, Lucheng; Zhang, Ke; Shen, Binghui; Chen, Xufeng; Ma, Shenglin

2016-10-18

Metastasis is the reason for most cancer death, and a crucial primary step for cancer metastasis is invasion of the surrounding tissue, which may be initiated by some rare tumor cells that escape the heterogeneous primary tumor. In this study, we isolated invasive subpopulations of cancer cells from human non-small cell lung cancer (NSCLC) H460 and H1299 cell lines, and determined the gene expression profiles and the responses of these invasive cancer cells to treatments of ionizing radiation and chemotherapeutic agents. The subpopulation of highly invasive NSCLC cells showed epigenetic signatures of epithelial-mesenchymal transition, cancer cell stemness, increased DNA damage repair and cell survival signaling. We also investigated the epigenetic therapy potential of suberoylanilide hydroxamic acid (SAHA) on invasive cancer cells, and found that SAHA suppresses cancer cell invasiveness and sensitizes cancer cells to treatments of IR and chemotherapeutic agents. Our results provide guidelines for identification of metastatic predictors and for clinical management of NSCLC. This study also suggests a beneficial clinical potential of SAHA as a chemotherapeutic agent for NSCLC patients.

Cancer stem cells and differentiation therapy.

PubMed

Jin, Xiong; Jin, Xun; Kim, Hyunggee

2017-10-01

Cancer stem cells can generate tumors from only a small number of cells, whereas differentiated cancer cells cannot. The prominent feature of cancer stem cells is its ability to self-renew and differentiate into multiple types of cancer cells. Cancer stem cells have several distinct tumorigenic abilities, including stem cell signal transduction, tumorigenicity, metastasis, and resistance to anticancer drugs, which are regulated by genetic or epigenetic changes. Like normal adult stem cells involved in various developmental processes and tissue homeostasis, cancer stem cells maintain their self-renewal capacity by activating multiple stem cell signaling pathways and inhibiting differentiation signaling pathways during cancer initiation and progression. Recently, many studies have focused on targeting cancer stem cells to eradicate malignancies by regulating stem cell signaling pathways, and products of some of these strategies are in preclinical and clinical trials. In this review, we describe the crucial features of cancer stem cells related to tumor relapse and drug resistance, as well as the new therapeutic strategy to target cancer stem cells named "differentiation therapy."

Clinical trials for stem cell transplantation: when are they needed?

PubMed

Van Pham, Phuc

2016-04-27

In recent years, both stem cell research and the clinical application of these promising cells have increased rapidly. About 1000 clinical trials using stem cells have to date been performed globally. More importantly, more than 10 stem cell-based products have been approved in some countries. With the rapid growth of stem cell applications, some countries have used clinical trials as a tool to diminish the rate of clinical stem cell applications. However, the point at which stem cell clinical trials are essential remains unclear. This commentary discusses when stem cell clinical trials are essential for stem cell transplantation therapies.

Advanced platelet-rich fibrin: a new concept for cell-based tissue engineering by means of inflammatory cells.

PubMed

Ghanaati, Shahram; Booms, Patrick; Orlowska, Anna; Kubesch, Alica; Lorenz, Jonas; Rutkowski, Jim; Landes, Constantin; Sader, Robert; Kirkpatrick, Cj; Choukroun, Joseph

2014-12-01

Choukroun's platelet-rich fibrin (PRF) is obtained from blood without adding anticoagulants. In this study, protocols for standard platelet-rich fibrin (S-PRF) (2700 rpm, 12 minutes) and advanced platelet-rich fibrin (A-PRF) (1500 rpm, 14 minutes) were compared to establish by histological cell detection and histomorphometrical measurement of cell distribution the effects of the centrifugal force (speed and time) on the distribution of cells relevant for wound healing and tissue regeneration. Immunohistochemistry for monocytes, T and B -lymphocytes, neutrophilic granulocytes, CD34-positive stem cells, and platelets was performed on clots produced from four different human donors. Platelets were detected throughout the clot in both groups, although in the A-PRF group, more platelets were found in the distal part, away from the buffy coat (BC). T- and B-lymphocytes, stem cells, and monocytes were detected in the surroundings of the BC in both groups. Decreasing the rpm while increasing the centrifugation time in the A-PRF group gave an enhanced presence of neutrophilic granulocytes in the distal part of the clot. In the S-PRF group, neutrophils were found mostly at the red blood cell (RBC)-BC interface. Neutrophilic granulocytes contribute to monocyte differentiation into macrophages. Accordingly, a higher presence of these cells might be able to influence the differentiation of host macrophages and macrophages within the clot after implantation. Thus, A-PRF might influence bone and soft tissue regeneration, especially through the presence of monocytes/macrophages and their growth factors. The relevance and feasibility of this tissue-engineering concept have to be proven through in vivo studies.

Stem cells - biological update and cell therapy progress

PubMed Central

GIRLOVANU, MIHAI; SUSMAN, SERGIU; SORITAU, OLGA; RUS-CIUCA, DAN; MELINCOVICI, CARMEN; CONSTANTIN, ANNE-MARIE; MIHU, CARMEN MIHAELA

2015-01-01

In recent years, the advances in stem cell research have suggested that the human body may have a higher plasticity than it was originally expected. Until now, four categories of stem cells were isolated and cultured in vivo: embryonic stem cells, fetal stem cells, adult stem cells and induced pluripotent stem cells (hiPSCs). Although multiple studies were published, several issues concerning the stem cells are still debated, such as: the molecular mechanisms of differentiation, the methods to prevent teratoma formation or the ethical and religious issues regarding especially the embryonic stem cell research. The direct differentiation of stem cells into specialized cells: cardiac myocytes, neural cells, pancreatic islets cells, may represent an option in treating incurable diseases such as: neurodegenerative diseases, type I diabetes, hematologic or cardiac diseases. Nevertheless, stem cell-based therapies, based on stem cell transplantation, remain mainly at the experimental stages and their major limitation is the development of teratoma and cancer after transplantation. The induced pluripotent stem cells (hiPSCs) represent a prime candidate for future cell therapy research because of their significant self-renewal and differentiation potential and the lack of ethical issues. This article presents an overview of the biological advances in the study of stem cells and the current progress made in the field of regenerative medicine. PMID:26609255

A Long-Gap Peripheral Nerve Injury Therapy Using Human Skeletal Muscle-Derived Stem Cells (Sk-SCs): An Achievement of Significant Morphological, Numerical and Functional Recovery

PubMed Central

Hirata, Maki; Nakajima, Nobuyuki; Saito, Kosuke; Hashimoto, Hiroyuki; Soeda, Shuichi; Uchiyama, Yoshiyasu; Watanabe, Masahiko

2016-01-01

Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs) to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34) and CD34-/45-/29+ (Sk-DN/29+) cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm) bridging an acellular conduit. After 8–12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells) were also observed. A significant tetanic tension recovery (over 90%) of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap) was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon) and functional (80% vs. 60% in tetanus) recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks) of recovery was observed in both groups with the expression of key factors (mRNA and protein levels), suggesting the paracrine effects to angiogenesis. These results suggested that the human Sk-SCs may be a practical source for autologous stem cell therapy following severe peripheral nerve injury. PMID:27846318

A Long-Gap Peripheral Nerve Injury Therapy Using Human Skeletal Muscle-Derived Stem Cells (Sk-SCs): An Achievement of Significant Morphological, Numerical and Functional Recovery.

PubMed

Tamaki, Tetsuro; Hirata, Maki; Nakajima, Nobuyuki; Saito, Kosuke; Hashimoto, Hiroyuki; Soeda, Shuichi; Uchiyama, Yoshiyasu; Watanabe, Masahiko

2016-01-01

Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs) to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34) and CD34-/45-/29+ (Sk-DN/29+) cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm) bridging an acellular conduit. After 8-12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells) were also observed. A significant tetanic tension recovery (over 90%) of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap) was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon) and functional (80% vs. 60% in tetanus) recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks) of recovery was observed in both groups with the expression of key factors (mRNA and protein levels), suggesting the paracrine effects to angiogenesis. These results suggested that the human Sk-SCs may be a practical source for autologous stem cell therapy following severe peripheral nerve injury.

Establishment of mouse expanded potential stem cells

PubMed Central

Gao, Xuefei; Antunes, Liliana; Yu, Yong; Zhu, Zhexin; Wang, Juexuan; Kolodziejczyk, Aleksandra A.; Campos, Lia S.; Wang, Cui; Yang, Fengtang; Zhong, Zhen; Fu, Beiyuan; Eckersley-Maslin, Melanie A.; Woods, Michael; Tanaka, Yosuke; Chen, Xi; Wilkinson, Adam C.; Bussell, James; White, Jacqui; Ramirez-Solis, Ramiro; Reik, Wolf; Göttgens, Berthold; Teichmann, Sarah A.; Tam, Patrick P. L.; Nakauchi, Hiromitsu; Zou, Xiangang; Lu, Liming; Liu, Pentao

2018-01-01

Mouse embryonic stem cells derived from the epiblast1 contribute to the somatic lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive endoderm2 upon reintroduction to the blastocyst. Here we report that cultures of expanded potential stem cells can be established from individual eight-cell blastomeres, and by direct conversion of mouse embryonic stem cells and induced pluripotent stem cells. Remarkably, a single expanded potential stem cell can contribute both to the embryo proper and to the trophectoderm lineages in a chimaera assay. Bona fide trophoblast stem cell lines and extra-embryonic endoderm stem cells can be directly derived from expanded potential stem cells in vitro. Molecular analyses of the epigenome and single-cell transcriptome reveal enrichment for blastomere-specific signature and a dynamic DNA methylome in expanded potential stem cells. The generation of mouse expanded potential stem cells highlights the feasibility of establishing expanded potential stem cells for other mammalian species. PMID:29019987

Adult Stem Cell Therapy for Stroke: Challenges and Progress

PubMed Central

Bang, Oh Young; Kim, Eun Hee; Cha, Jae Min; Moon, Gyeong Joon

2016-01-01

Stroke is one of the leading causes of death and physical disability among adults. It has been 15 years since clinical trials of stem cell therapy in patients with stroke have been conducted using adult stem cells like mesenchymal stem cells and bone marrow mononuclear cells. Results of randomized controlled trials showed that adult stem cell therapy was safe but its efficacy was modest, underscoring the need for new stem cell therapy strategies. The primary limitations of current stem cell therapies include (a) the limited source of engraftable stem cells, (b) the presence of optimal time window for stem cell therapies, (c) inherited limitation of stem cells in terms of growth, trophic support, and differentiation potential, and (d) possible transplanted cell-mediated adverse effects, such as tumor formation. Here, we discuss recent advances that overcome these hurdles in adult stem cell therapy for stroke. PMID:27733032

Two sides of the same coin? Unraveling subtle differences between human embryonic and induced pluripotent stem cells by Raman spectroscopy.

PubMed

Parrotta, Elvira; De Angelis, Maria Teresa; Scalise, Stefania; Candeloro, Patrizio; Santamaria, Gianluca; Paonessa, Mariagrazia; Coluccio, Maria Laura; Perozziello, Gerardo; De Vitis, Stefania; Sgura, Antonella; Coluzzi, Elisa; Mollace, Vincenzo; Di Fabrizio, Enzo Mario; Cuda, Giovanni

2017-11-28

Human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells, hold enormous promise for many biomedical applications, such as regenerative medicine, drug testing, and disease modeling. Although induced pluripotent stem cells resemble embryonic stem cells both morphologically and functionally, the extent to which these cell lines are truly equivalent, from a molecular point of view, remains controversial. Principal component analysis and K-means cluster analysis of collected Raman spectroscopy data were used for a comparative study of the biochemical fingerprint of human induced pluripotent stem cells and human embryonic stem cells. The Raman spectra analysis results were further validated by conventional biological assays. Raman spectra analysis revealed that the major difference between human embryonic stem cells and induced pluripotent stem cells is due to the nucleic acid content, as shown by the strong positive peaks at 785, 1098, 1334, 1371, 1484, and 1575 cm -1 , which is enriched in human induced pluripotent stem cells. Here, we report a nonbiological approach to discriminate human induced pluripotent stem cells from their native embryonic stem cell counterparts.

Postnatal neurogenesis in the cow pineal gland: an immunohistochemical study.

PubMed

Gómez Esteban, M B; Muñoz Mosqueira, M I; Arroyo, A A; Muñoz Barragán, L

2013-03-01

In the pineal gland of cows and rats structures designated rosettes have been described both during embryonic development and in adult animals. In order to investigate the possible nature of the cells comprising such structures, in the present work we studied the pineal glands from 10 cows of one- or four-years-old using conventional immunocytochemical and confocal microscopy techniques. As markers of glial cells, we used anti-vimentin (Vim) and glial fibrillary acidic protein (GFAP) and anti-S-100 sera, and the pinealocytes were labelled with β-III tubulin. As a marker of stem cells, we used an antinestin serum, while an anti-PCNA serum was employed to label proliferating cells. To explore the neuronal nature of some cells of the rosettes, we used an anti-SRIF serum. The rosettes were seen to be present throughout the glandular parenchyma and displayed a central cavity surrounded by cells, most of which expressed all or just some of the above glial labels and nestin, although there were also some rosettes with cells that expressed β-III tubulin and other cells that expressed SRIF. Likewise, in the cells of the rosettes the cell nucleus showed strong expression of PCNA. Confocal microscopy revealed that the walls of the rosettes contained cells that coexpressed Vim/S-100, Vim/GFAP and Vim/nestin. The number of rosettes was significantly greater in the animals of one year of age with respect to the four-year-old cows. The present findings allow us to suggest that rosettes are evolving structures and that most of the cells present in their walls should be considered stem cells, and hence responsible for the postnatal neurogenesis occurring in the pineal gland of cows.

Telocytes and putative stem cells in the lungs: electron microscopy, electron tomography and laser scanning microscopy.

PubMed

Popescu, Laurentiu M; Gherghiceanu, Mihaela; Suciu, Laura C; Manole, Catalin G; Hinescu, Mihail E

2011-09-01

This study describes a novel type of interstitial (stromal) cell - telocytes (TCs) - in the human and mouse respiratory tree (terminal and respiratory bronchioles, as well as alveolar ducts). TCs have recently been described in pleura, epicardium, myocardium, endocardium, intestine, uterus, pancreas, mammary gland, etc. (see www.telocytes.com ). TCs are cells with specific prolongations called telopodes (Tp), frequently two to three per cell. Tp are very long prolongations (tens up to hundreds of μm) built of alternating thin segments known as podomers (≤ 200 nm, below the resolving power of light microscope) and dilated segments called podoms, which accommodate mitochondria, rough endoplasmic reticulum and caveolae. Tp ramify dichotomously, making a 3-dimensional network with complex homo- and heterocellular junctions. Confocal microscopy reveals that TCs are c-kit- and CD34-positive. Tp release shed vesicles or exosomes, sending macromolecular signals to neighboring cells and eventually modifying their transcriptional activity. At bronchoalveolar junctions, TCs have been observed in close association with putative stem cells (SCs) in the subepithelial stroma. SCs are recognized by their ultrastructure and Sca-1 positivity. Tp surround SCs, forming complex TC-SC niches (TC-SCNs). Electron tomography allows the identification of bridging nanostructures, which connect Tp with SCs. In conclusion, this study shows the presence of TCs in lungs and identifies a TC-SC tandem in subepithelial niches of the bronchiolar tree. In TC-SCNs, the synergy of TCs and SCs may be based on nanocontacts and shed vesicles.

A family business: stem cell progeny join the niche to regulate homeostasis.

PubMed

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-23

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems.

A family business: stem cell progeny join the niche to regulate homeostasis

PubMed Central

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-01

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems. PMID:22266760

Stem Cell Therapy for Erectile Dysfunction.

PubMed

Matz, Ethan L; Terlecki, Ryan; Zhang, Yuanyuan; Jackson, John; Atala, Anthony

2018-04-06

The prevalence of erectile dysfunction (ED) is substantial and continues to rise. Current therapeutics for ED consist of oral medications, intracavernosal injections, vacuum erection devices, and penile implants. While such options may manage the disease state, none of these modalities, however, restore function. Stem cell therapy has been evaluated for erectile restoration in animal models. These cells have been derived from multiple tissues, have varied potential, and may function via local engraftment or paracrine signaling. Bone marrow-derived stem cells (BMSC) and adipose-derived stem cells (ASC) have both been used in these models with noteworthy effects. Herein, we will review the pathophysiology of ED, animal models, current and novel stem-cell based therapeutics, clinical trials and areas for future research. The relevant literature and contemporary data using keywords, "stem cells and erectile dysfunction" was reviewed. Examination of evidence supporting the association between erectile dysfunction and adipose derived stem cells, bone marrow derived stem cells, placental stem cells, urine stem cells and stem cell therapy respectively. Placental-derived stem cells and urine-derived stem cells possess many similar properties as BMSC and ASC, but the methods of acquisition are favorable. Human clinical trials have already demonstrated successful use of stem cells for improvement of erectile function. The future of stem cell research is constantly being evaluated, although, the evidence suggests a place for stem cells in erectile dysfunction therapeutics. Matz EL, Terlecki R, Zhang Y, et al. Stem Cell Therapy for Erectile Dysfunction. Sex Med Rev 2018;XX:XXX-XXX. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

A new prospect in cancer therapy: targeting cancer stem cells to eradicate cancer.

PubMed

Chen, Li-Sha; Wang, An-Xin; Dong, Bing; Pu, Ke-Feng; Yuan, Li-Hua; Zhu, Yi-Min

2012-12-01

According to the cancer stem cell theory, cancers can be initiated by cancer stem cells. This makes cancer stem cells prime targets for therapeutic intervention. Eradicating cancer stem cells by efficient targeting agents may have the potential to cure cancer. In this review, we summarize recent breakthroughs that have improved our understanding of cancer stem cells, and we discuss the therapeutic strategy of targeting cancer stem cells, a promising future direction for cancer stem cell research.

Adult bone marrow-derived stem cells for organ regeneration and repair.

PubMed

Tögel, Florian; Westenfelder, Christof

2007-12-01

Stem cells have been recognized as a potential tool for the development of innovative therapeutic strategies. There are in general two types of stem cells, embryonic and adult stem cells. While embryonic stem cell therapy has been riddled with problems of allogeneic rejection and ethical concerns, adult stem cells have long been used in the treatment of hematological malignancies. With the recognition of additional, potentially therapeutic characteristics, bone marrow-derived stem cells have become a tool in regenerative medicine. The bone marrow is an ideal source of stem cells because it is easily accessible and harbors two types of stem cells. Hematopoietic stem cells give rise to all blood cell types and have been shown to exhibit plasticity, while multipotent marrow stromal cells are the source of osteocytes, chondrocytes, and fat cells and have been shown to support and generate a large number of different cell types. This review describes the general characteristics of these stem cell populations and their current and potential future applications in regenerative medicine. 2007 Wiley-Liss, Inc

Design and optimization of a tissue-engineered bone graft substitute

NASA Astrophysics Data System (ADS)

Shimko, Daniel Andrew

2004-12-01

In 2000, 3.1 million surgical procedures on the musculoskeletal system were reported in the United States. For many of these cases, bone grafting was essential for successful fracture stabilization. Current techniques use intact bone obtained either from the patient (autograft) or a cadaver (allograft) to repair large defects, however, neither source is optimal. Allografts suffer integration problems, and for autografts, the tissue supply is limited. Because of these shortcomings, and the high demand for graft tissues, alternatives are being explored. To successfully engineer a bone graft replacement, one must employ a three pronged research approach, addressing (1) the cells that will inhabit the new tissue, (2) the culture environment that these cells will be exposed to, and (3) the scaffold in which these cells will reside. The work herein examines each of these three aspects in great detail. Both adult and embryonic stem cells (ESCs) were considered for the tissue-engineered bone graft. Both exhibited desirable qualities, however, neither were optimal in all categories examined. In the end, the possibility of teratoma formation and ethical issues surrounding ESCs, made the use of adult marrow-derived stem cells in the remaining experiments obligatory. In subsequent experiments, the adult stem cells' ability to form bone was optimized. Basic fibroblast growth factor, fetal bovine serum, and extracellular calcium supplementation studies were all performed. Ultimately, adult stem cells cultured in alpha-MEM supplemented with 10% fetal bovine serum, 10mM beta-glycerophosphate, 10nM dexamethasone, 50mug/ml ascorbic acid, 1%(v/v) antibiotic/antimycotic, and 10.4mM CaCl2 performed the best, producing nearly four times more mineral than any other medium formulation. Several scaffolds were then investigated including those fabricated from poly(alpha-hydroxy esters), tantalum, and poly-methylmethacrylate. In the final study, the most appealing cell type, medium formulation, and scaffold material from all preceding studies were combined and a tissue-engineered bone graft was fabricated. The graft was exposed to long-term in vitro culture, and then mechanically evaluated to determine its clinical potential. The studies contained herein constitute the first steps in the conception and development of a viable tissue-engineered bone graft substitute and establish a solid scientific foundation for future in vivo experimentation utilizing this design.

Stem cells.

PubMed

Behr, Björn; Ko, Sae Hee; Wong, Victor W; Gurtner, Geoffrey C; Longaker, Michael T

2010-10-01

Stem cells are self-renewing cells capable of differentiating into multiple cell lines and are classified according to their origin and their ability to differentiate. Enormous potential exists in use of stem cells for regenerative medicine. To produce effective stem cell-based treatments for a range of diseases, an improved understanding of stem cell biology and better control over stem cell fate are necessary. In addition, the barriers to clinical translation, such as potential oncologic properties of stem cells, need to be addressed. With renewed government support and continued refinement of current stem cell methodologies, the future of stem cell research is exciting and promises to provide novel reconstructive options for patients and surgeons limited by traditional paradigms.

Some Ethical Concerns About Human Induced Pluripotent Stem Cells.

PubMed

Zheng, Yue Liang

2016-10-01

Human induced pluripotent stem cells can be obtained from somatic cells, and their derivation does not require destruction of embryos, thus avoiding ethical problems arising from the destruction of human embryos. This type of stem cell may provide an important tool for stem cell therapy, but it also results in some ethical concerns. It is likely that abnormal reprogramming occurs in the induction of human induced pluripotent stem cells, and that the stem cells generate tumors in the process of stem cell therapy. Human induced pluripotent stem cells should not be used to clone human beings, to produce human germ cells, nor to make human embryos. Informed consent should be obtained from patients in stem cell therapy.

Laser biomodulation on stem cells

NASA Astrophysics Data System (ADS)

Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

2001-08-01

Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells.

PubMed

Kang, N-H; Hwang, K-A; Kim, S U; Kim, Y-B; Hyun, S-H; Jeung, E-B; Choi, K-C

2012-08-01

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

In vitro differentiation of primordial germ cells and oocyte-like cells from stem cells.

PubMed

Costa, José J N; Souza, Glaucinete B; Soares, Maria A A; Ribeiro, Regislane P; van den Hurk, Robert; Silva, José R V

2018-02-01

Infertility is the result of failure due to an organic disorder of the reproductive organs, especially their gametes. Recently, much progress has been made on generating germ cells, including oocytes, from various types of stem cells. This review focuses on advances in female germ cell differentiation from different kinds of stem cells, with emphasis on embryonic stem cells, adult stem cells, and induced pluripotent stem cells. The advantages and disadvantages of the derivation of female germ cells from several types of stem cells are also highlighted, as well as the ability of stem cells to generate mature and functional female gametes. This review shows that stem cell therapies have opened new frontiers in medicine, especially in the reproductive area, with the possibility of regenerating fertility.

Reduced hematopoietic stem cell frequency predicts outcome in acute myeloid leukemia.

PubMed

Wang, Wenwen; Stiehl, Thomas; Raffel, Simon; Hoang, Van T; Hoffmann, Isabel; Poisa-Beiro, Laura; Saeed, Borhan R; Blume, Rachel; Manta, Linda; Eckstein, Volker; Bochtler, Tilmann; Wuchter, Patrick; Essers, Marieke; Jauch, Anna; Trumpp, Andreas; Marciniak-Czochra, Anna; Ho, Anthony D; Lutz, Christoph

2017-09-01

In patients with acute myeloid leukemia and low percentages of aldehyde-dehydrogenase-positive cells, non-leukemic hematopoietic stem cells can be separated from leukemic cells. By relating hematopoietic stem cell frequencies to outcome we detected poor overall- and disease-free survival of patients with low hematopoietic stem cell frequencies. Serial analysis of matched diagnostic and follow-up samples further demonstrated that hematopoietic stem cells increased after chemotherapy in patients who achieved durable remissions. However, in patients who eventually relapsed, hematopoietic stem cell numbers decreased dramatically at the time of molecular relapse demonstrating that hematopoietic stem cell levels represent an indirect marker of minimal residual disease, which heralds leukemic relapse. Upon transplantation in immune-deficient mice cases with low percentages of hematopoietic stem cells of our cohort gave rise to leukemic or no engraftment, whereas cases with normal hematopoietic stem cell levels mostly resulted in multi-lineage engraftment. Based on our experimental data, we propose that leukemic stem cells have increased niche affinity in cases with low percentages of hematopoietic stem cells. To validate this hypothesis, we developed new mathematical models describing the dynamics of healthy and leukemic cells under different regulatory scenarios. These models suggest that the mechanism leading to decreases in hematopoietic stem cell frequencies before leukemic relapse must be based on expansion of leukemic stem cells with high niche affinity and the ability to dislodge hematopoietic stem cells. Thus, our data suggest that decreasing numbers of hematopoietic stem cells indicate leukemic stem cell persistence and the emergence of leukemic relapse. Copyright© 2017 Ferrata Storti Foundation.

Immunomodulatory Effects of Adipose Stromal Vascular Fraction Cells Promote Alternative Activation Macrophages to Repair Tissue Damage.

PubMed

Bowles, Annie C; Wise, Rachel M; Gerstein, Brittany Y; Thomas, Robert C; Ogelman, Roberto; Febbo, Isabella; Bunnell, Bruce A

2017-10-01

The pathogenesis of many diseases is driven by the interactions between helper T (T H ) cells and macrophages. The phenotypes of these cells are functional dichotomies that are persuaded according to the surrounding milieu. In both multiple sclerosis and the experimental autoimmune encephalomyelitis (EAE) model, T H 1 and T H 17 cells propagate autoimmune signaling and inflammation in the peripheral lymphoid tissues. In turn, this proinflammatory repertoire promotes the classical activation, formerly the M1-type, macrophages. Together, these cells infiltrate into the central nervous system (CNS) tissues and generate inflammatory and demyelinating lesions. Our most recent report demonstrated the immunomodulatory and anti-inflammatory effects of adipose stromal vascular fraction (SVF) cells and adipose-derived stem cells (ASCs) that led to functional, immunological, and pathological improvements in the EAE model. Here, a deeper investigation revealed the induction of regulatory T cells and alternative activation, or M2-type, macrophages in the periphery followed by the presence of alternative activation macrophages, reduced cellular infiltrates, and attenuation of neuroinflammation in CNS tissues following intraperitoneal administration of these treatments. Spleens from treated EAE mice revealed diminished T H 1 and T H 17 cell activities and were markedly higher in the levels of anti-inflammatory cytokine interleukin-10. Interestingly, SVF cells were more effective than ASCs at mediating these beneficial changes, which were attributed to their localization to the spleens after administration. Together, SVF cells rapidly and robustly attenuated the propagation of autoimmune signaling in the periphery that provided a permissive milieu in the CNS for repair and possibly regeneration. Stem Cells 2017;35:2198-2207. © 2017 AlphaMed Press.

Evaluation of the secretion and release of vascular endothelial growth factor from two-dimensional culture and three-dimensional cell spheroids formed with stem cells and osteoprecursor cells.

PubMed

Lee, Hyunjin; Lee, Sung-Il; Ko, Youngkyung; Park, Jun-Beom

2018-05-18

Co-culture has been applied in cell therapy, including stem cells, and has been reported to give enhanced functionality. In this study, stem-cell spheroids were formed in concave micromolds at different ratios of stem cells to osteoprecursor cells, and the amount of secretion of vascular endothelial growth factor (VEGF) was evaluated. Gingiva-derived stem cells and osteoprecursor cells in the amount of 6 × 105 were seeded on a 24-well culture plate or concave micromolds. The ratios of stem cells to osteoprecursor cells included: 0:4 (group 1), 1:3 (group 2), 2:2 (group 3), 3:1 (group 4), and 4:0 (group 5). The morphology of cells in a 2-dimensional culture (groups 1-5) showed a fibroblast-like appearance. The secretion of VEGF increased with the increase in stem cells, and a statistically significant increase was noted in groups 3, 4 and 5 when compared with the media-only group (p < 0.05). Osteoprecursor cells formed spheroids in concave microwells, and no noticeable change in the morphology was noted with the increase in stem cells. Spheroids containing stem cells were positive for the stem-cell markers SSEA-4. The secretion of VEGF from cell spheroids increased with the increase in stem cells. This study showed that cell spheroids formed with stem cells and osteoprecursor cells with different ratios, using microwells, had paracrine effects on the stem cells. The secretion of VEGF increased with the increase in stem cells. This stem-cell spheroid may be applied for tissue-engineering purposes.

Ovarian steroids, stem cells and uterine leiomyoma: therapeutic implications

PubMed Central

Moravek, Molly B.; Yin, Ping; Ono, Masanori; Coon V, John S.; Dyson, Matthew T.; Navarro, Antonia; Marsh, Erica E.; Chakravarti, Debabrata; Kim, J. Julie; Wei, Jian-Jun; Bulun, Serdar E.

2015-01-01

BACKGROUND Uterine leiomyoma is the most common benign tumor in women and is thought to arise from the clonal expansion of a single myometrial smooth muscle cell transformed by a cellular insult. Leiomyomas cause a variety of symptoms, including abnormal uterine bleeding, pelvic pain, bladder or bowel dysfunction, and recurrent pregnancy loss, and are the most common indication for hysterectomy in the USA. A slow rate of cell proliferation, combined with the production of copious amounts of extracellular matrix, accounts for tumor expansion. A common salient feature of leiomyomas is their responsiveness to steroid hormones, thus providing an opportunity for intervention. METHODS A comprehensive search of PUBMED was conducted to identify peer-reviewed literature published since 1980 pertinent to the roles of steroid hormones and somatic stem cells in leiomyoma, including literature on therapeutics that target steroid hormone action in leiomyoma. Reviewed articles were restricted to English language only. Studies in both animals and humans were reviewed for the manuscript. RESULTS Estrogen stimulates the growth of leiomyomas, which are exposed to this hormone not only through ovarian steroidogenesis, but also through local conversion of androgens by aromatase within the tumors themselves. The primary action of estrogen, together with its receptor estrogen receptor α (ERα), is likely mediated via induction of progesterone receptor (PR) expression, thereby allowing leiomyoma responsiveness to progesterone. Progesterone has been shown to stimulate the growth of leiomyoma through a set of key genes that regulate both apoptosis and proliferation. Given these findings, aromatase inhibitors and antiprogestins have been developed for the treatment of leiomyoma, but neither treatment results in complete regression of leiomyoma, and tumors recur after treatment is stopped. Recently, distinct cell populations were discovered in leiomyomas; a small population showed stem-progenitor cell properties, and was found to be essential for ovarian steroid-dependent growth of leiomyomas. Interestingly, these stem-progenitor cells were deficient in ERα and PR and instead relied on the strikingly higher levels of these receptors in surrounding differentiated cells to mediate estrogen and progesterone action via paracrine signaling. CONCLUSIONS It has been well established that estrogen and progesterone are involved in the proliferation and maintenance of uterine leiomyoma, and the majority of medical treatments currently available for leiomyoma work by inhibiting steroid hormone production or action. A pitfall of these therapeutics is that they decrease leiomyoma size, but do not completely eradicate them, and tumors tend to regrow once treatment is stopped. The recent discovery of stem cells and their paracrine interactions with more differentiated cell populations within leiomyoma has the potential to provide the missing link between developing therapeutics that temper leiomyoma growth and those that eradicate them. PMID:25205766

Dose Dependent Side Effect of Superparamagnetic Iron Oxide Nanoparticle Labeling on Cell Motility in Two Fetal Stem Cell Populations

PubMed Central

Diana, Valentina; Bossolasco, Patrizia; Moscatelli, Davide; Silani, Vincenzo; Cova, Lidia

2013-01-01

Multipotent stem cells (SCs) could substitute damaged cells and also rescue degeneration through the secretion of trophic factors able to activate the endogenous SC compartment. Therefore, fetal SCs, characterized by high proliferation rate and devoid of ethical concern, appear promising candidate, particularly for the treatment of neurodegenerative diseases. Super Paramagnetic Iron Oxide nanoparticles (SPIOn), routinely used for pre-clinical cell imaging and already approved for clinical practice, allow tracking of transplanted SCs and characterization of their fate within the host tissue, when combined with Magnetic Resonance Imaging (MRI). In this work we investigated how SPIOn could influence cell migration after internalization in two fetal SC populations: human amniotic fluid and chorial villi SCs were labeled with SPIOn and their motility was evaluated. We found that SPIOn loading significantly reduced SC movements without increasing production of Reactive Oxygen Species (ROS). Moreover, motility impairment was directly proportional to the amount of loaded SPIOn while a chemoattractant-induced recovery was obtained by increasing serum levels. Interestingly, the migration rate of SPIOn labeled cells was also significantly influenced by a degenerative surrounding. In conclusion, this work highlights how SPIOn labeling affects SC motility in vitro in a dose-dependent manner, shedding the light on an important parameter for the creation of clinical protocols. Establishment of an optimal SPIOn dose that enables both a good visualization of grafted cells by MRI and the physiological migration rate is a main step in order to maximize the effects of SC therapy in both animal models of neurodegeneration and clinical studies. PMID:24244310

The Role of Stem Cells in Aesthetic Surgery: Fact or Fiction?

PubMed Central

McArdle, Adrian; Senarath-Yapa, Kshemendra; Walmsley, Graham G.; Hu, Michael; Atashroo, David A.; Tevlin, Ruth; Zielins, Elizabeth; Gurtner, Geoffrey C.; Wan, Derrick C.; Longaker, Michael T.

2014-01-01

Stem cells are attractive candidates for the development of novel therapies, targeting indications that involve functional restoration of defective tissue. Although most stem cell therapies are new and highly experimental, there are clinics around the world that exploit vulnerable patients with the hope of offering supposed stem cell therapies, many of which operate without credible scientific merit, oversight, or other patient protection. We review the potential, as well as drawbacks, for incorporation of stem cells in cosmetic procedures. A review of FDA-approved indications and ongoing clinical trials with adipose stem cells is provided. Furthermore, a “snapshot” analysis of websites using the search terms “stem cell therapy” or “stem cell treatment” or “stem cell facelift” was performed. Despite the protective net cast by regulatory agencies such as the FDA and professional societies such as the American Society of Plastic Surgeons, we are witnessing worrying advertisements for procedures such as stem cell facelifts, stem cell breast augmentations, and even stem cell vaginal rejuvenation. The marketing and promotion of stem cell procedures in aesthetic surgery is not adequately supported by clinical evidence in the majority of cases. Stem cells offer tremendous potential, but the marketplace is saturated with unsubstantiated and sometimes fraudulent claims that may place patients at risk. With plastic surgeons at the forefront of stem cell-based regenerative medicine, it is critically important that we provide an example of a rigorous approach to research, data collection, and advertising of stem cell therapies. PMID:24732654

A WUSCHEL-Independent Stem Cell Specification Pathway Is Repressed by PHB, PHV and CNA in Arabidopsis.

PubMed

Lee, Chunghee; Clark, Steven E

2015-01-01

The homeostatic maintenance of stem cells that carry out continuous organogenesis at the shoot meristem is crucial for plant development. Key known factors act to signal between the stem cells and an underlying group of cells thought to act as the stem cell niche. In Arabidopsis thaliana the homeodomain transcription factor WUSCHEL (WUS) is essential for stem cell initiation and maintenance at shoot and flower meristems. Recent data suggest that the WUS protein may move from the niche cells directly into the stem cells to maintain stem cell identity. Here we provide evidence for a second, previously unknown, pathway for stem cell specification at shoot and flower meristems that bypasses the requirement for WUS. We demonstrate that this novel stem cell specification pathway is normally repressed by the activity of the HD-zip III transcription factors PHABULOSA (PHB), PHAVOLUTA (PHV) and CORONA (CNA). When de-repressed, this second stem cell pathway leads to an accumulation of stem cells and an enlargement of the stem cell niche. When de-repressed in a wus mutant background, this second stem cell pathway leads to functional meristems with largely normal cell layering and meristem morphology, activation of WUS cis regulatory elements, and extensive, but not indeterminate, organogenesis. Thus, WUS is largely dispensable for stem cell specification and meristem function, suggesting a set of key stem cell specification factors, competitively regulated by WUS and PHB/PHV/CNA, remain unidentified.

A WUSCHEL-Independent Stem Cell Specification Pathway Is Repressed by PHB, PHV and CNA in Arabidopsis

PubMed Central

Lee, Chunghee; Clark, Steven E.

2015-01-01

The homeostatic maintenance of stem cells that carry out continuous organogenesis at the shoot meristem is crucial for plant development. Key known factors act to signal between the stem cells and an underlying group of cells thought to act as the stem cell niche. In Arabidopsis thaliana the homeodomain transcription factor WUSCHEL (WUS) is essential for stem cell initiation and maintenance at shoot and flower meristems. Recent data suggest that the WUS protein may move from the niche cells directly into the stem cells to maintain stem cell identity. Here we provide evidence for a second, previously unknown, pathway for stem cell specification at shoot and flower meristems that bypasses the requirement for WUS. We demonstrate that this novel stem cell specification pathway is normally repressed by the activity of the HD-zip III transcription factors PHABULOSA (PHB), PHAVOLUTA (PHV) and CORONA (CNA). When de-repressed, this second stem cell pathway leads to an accumulation of stem cells and an enlargement of the stem cell niche. When de-repressed in a wus mutant background, this second stem cell pathway leads to functional meristems with largely normal cell layering and meristem morphology, activation of WUS cis regulatory elements, and extensive, but not indeterminate, organogenesis. Thus, WUS is largely dispensable for stem cell specification and meristem function, suggesting a set of key stem cell specification factors, competitively regulated by WUS and PHB/PHV/CNA, remain unidentified. PMID:26011610

Generation, characterization and potential therapeutic applications of mature and functional hepatocytes from stem cells.

PubMed

Zhang, Zhenzhen; Liu, Jianfang; Liu, Yang; Li, Zheng; Gao, Wei-Qiang; He, Zuping

2013-02-01

Liver cancer is the sixth most common tumor in the world and the majority of patients with this disease usually die within 1 year. The effective treatment for end-stage liver disease (also known as liver failure), including liver cancer or cirrhosis, is liver transplantation. However, there is a severe shortage of liver donors worldwide, which is the major handicap for the treatment of patients with liver failure. Scarcity of liver donors underscores the urgent need of using stem cell therapy to the end-stage liver disease. Notably, hepatocytes have recently been generated from hepatic and extra-hepatic stem cells. We have obtained mature and functional hepatocytes from rat hepatic stem cells. Here, we review the advancements on hepatic differentiation from various stem cells, including hepatic stem cells, embryonic stem cells, the induced pluripotent stem cells, hematopoietic stem cells, mesenchymal stem cells, and probably spermatogonial stem cells. The advantages, disadvantages, and concerns on differentiation of these stem cells into hepatic cells are highlighted. We further address the methodologies, phenotypes, and functional characterization on the differentiation of numerous stem cells into hepatic cells. Differentiation of stem cells into mature and functional hepatocytes, especially from an extra-hepatic stem cell source, would circumvent the scarcity of liver donors and human hepatocytes, and most importantly it would offer an ideal and promising source of hepatocytes for cell therapy and tissue engineering in treating liver disease. Copyright © 2012 Wiley Periodicals, Inc.

Vitronectin-Based, Biomimetic Encapsulating Hydrogel Scaffolds Support Adipogenesis of Adipose Stem Cells

PubMed Central

Clevenger, Tracy N.; Hinman, Cassidy R.; Ashley Rubin, Rebekah K.; Smither, Kate; Burke, Daniel J.; Hawker, Craig J.; Messina, Darin; Van Epps, Dennis

2016-01-01

Soft tissue defects are relatively common, yet currently used reconstructive treatments have varying success rates, and serious potential complications such as unpredictable volume loss and reabsorption. Human adipose-derived stem cells (ASCs), isolated from liposuction aspirate have great potential for use in soft tissue regeneration, especially when combined with a supportive scaffold. To design scaffolds that promote differentiation of these cells down an adipogenic lineage, we characterized changes in the surrounding extracellular environment during adipogenic differentiation. We found expression changes in both extracellular matrix proteins, including increases in expression of collagen-IV and vitronectin, as well as changes in the integrin expression profile, with an increase in expression of integrins such as αVβ5 and α1β1. These integrins are known to specifically interact with vitronectin and collagen-IV, respectively, through binding to an Arg-Gly-Asp (RGD) sequence. When three different short RGD-containing peptides were incorporated into three-dimensional (3D) hydrogel cultures, it was found that an RGD-containing peptide derived from vitronectin provided strong initial attachment, maintained the desired morphology, and created optimal conditions for in vitro 3D adipogenic differentiation of ASCs. These results describe a simple, nontoxic encapsulating scaffold, capable of supporting the survival and desired differentiation of ASCs for the treatment of soft tissue defects. PMID:26956095

Repair of full-thickness articular cartilage defect using stem cell-encapsulated thermogel.

PubMed

Zhang, Yanbo; Zhang, Jin; Chang, Fei; Xu, Weiguo; Ding, Jianxun

2018-07-01

Cartilage defect repair by hydrogel-based tissue engineering is becoming one of the most potential treatment strategies. In this work, a thermogel of triblock copolymer poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) was prepared as scaffold of bone marrow mesenchymal stem cells (BMMSCs) for repair of full-thickness articular cartilage defect. At first, the copolymer solution showed a reversible sol-gel transition at physiological temperature range, and the mechanical properties of such thermogel were high enough to support the repair of cartilage. Additionally, excellent biodegradability and biocompatibility of the thermogel were demonstrated. By implanting the BMMSC-encapsulated thermogel into the full-thickness articular cartilage defect (5.0 mm in diameter and 4.0 mm in depth) in the rabbit, it was found that the regenerated cartilage integrated well with the surrounding normal cartilage and subchondral bone at 12 weeks post-surgery. The upregulated expression of glycosaminoglycan and type II collagen in the repaired cartilage, and the comparable biomechanical properties with normal cartilage suggested that the cell-encapsulated PLGA-PEG-PLGA thermogel had great potential in serving as the promising scaffold for cartilage regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Stem cells in dentistry--part I: stem cell sources.

PubMed

Egusa, Hiroshi; Sonoyama, Wataru; Nishimura, Masahiro; Atsuta, Ikiru; Akiyama, Kentaro

2012-07-01

Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties. Copyright © 2012 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Plant stem cell niches.

PubMed

Stahl, Yvonne; Simon, Rüdiger

2005-01-01

Stem cells are required to support the indeterminate growth style of plants. Meristems are a plants stem cell niches that foster stem cell survival and the production of descendants destined for differentiation. In shoot meristems, stem cell fate is decided at the populational level. The size of the stem cell domain at the meristem tip depends on signals that are exchanged with cells of the organizing centre underneath. In root meristems, individual stem cells are controlled by direct interaction with cells of the quiescent centre that lie in the immediate neighbourhood. Analysis of the interactions and signaling processes in the stem cell niches has delivered some insights into the molecules that are involved and revealed that the two major niches for plant stem cells are more similar than anticipated.

Stem cells in the Drosophila digestive system.

PubMed

Zeng, Xiankun; Chauhan, Chhavi; Hou, Steven X

2013-01-01

Adult stem cells maintain tissue homeostasis by continuously replenishing damaged, aged and dead cells in any organism. Five types of region and organ-specific multipotent adult stem cells have been identified in the Drosophila digestive system: intestinal stem cells (ISCs) in the posterior midgut; hindgut intestinal stem cells (HISCs) at the midgut/hindgut junction; renal and nephric stem cells (RNSCs) in the Malpighian Tubules; type I gastric stem cells (GaSCs) at foregut/midgut junction; and type II gastric stem cells (GSSCs) at the middle of the midgut. Despite the fact that each type of stem cell is unique to a particular organ, they share common molecular markers and some regulatory signaling pathways. Due to the simpler tissue structure, ease of performing genetic analysis, and availability of abundant mutants, Drosophila serves as an elegant and powerful model system to study complex stem cell biology. The recent discoveries, particularly in the Drosophila ISC system, have greatly advanced our understanding of stem cell self-renewal, differentiation, and the role of stem cells play in tissue homeostasis/regeneration and adaptive tissue growth.

Induced cancer stem cells generated by radiochemotherapy and their therapeutic implications.

PubMed

Chen, Xiewan; Liao, Rongxia; Li, Dezhi; Sun, Jianguo

2017-03-07

Local and distant recurrence of malignant tumors following radio- and/or chemotherapy correlates with poor prognosis of patients. Among the reasons for cancer recurrence, preexisting cancer stem cells (CSCs) are considered the most likely cause due to their properties of self-renewal, pluripotency, plasticity and tumorigenicity. It has been demonstrated that preexisting cancer stem cells derive from normal stem cells and differentiated somatic cells that undergo transformation and dedifferentiation respectively under certain conditions. However, recent studies have revealed that cancer stem cells can also be induced from non-stem cancer cells by radiochemotherapy, constituting the subpopulation of induced cancer stem cells (iCSCs). These findings suggest that radiochemotherapy has the side effect of directly transforming non-stem cancer cells into induced cancer stem cells, possibly contributing to tumor recurrence and metastasis. Therefore, drugs targeting cancer stem cells or preventing dedifferentiation of non-stem cancer cells can be combined with radiochemotherapy to improve its antitumor efficacy. The current review is to investigate the mechanisms by which induced cancer stem cells are generated by radiochemotherapy and hence provide new strategies for cancer treatment.

Stem cells in gastroenterology and hepatology

PubMed Central

Quante, Michael; Wang, Timothy C.

2010-01-01

Cellular and tissue regeneration in the gastrointestinal tract and liver depends on stem cells with properties of longevity, self-renewal and multipotency. Progress in stem cell research and the identification of potential esophageal, gastric, intestinal, colonic, hepatic and pancreatic stem cells provides hope for the use of stem cells in regenerative medicine and treatments for disease. Embryonic stem cells and induced pluripotent stem cells have the potential to give rise to any cell type in the human body, but their therapeutic application remains challenging. The use of adult or tissue-restricted stem cells is emerging as another possible approach for the treatment of gastrointestinal diseases. The same self-renewal properties that allow stem cells to remain immortal and generate any tissue can occasionally make their proliferation difficult to control and make them susceptible to malignant transformation. This Review provides an overview of the different types of stem cell, focusing on tissue-restricted adult stem cells in the fields of gastroenterology and hepatology and summarizing the potential benefits and risks of using stems cells to treat gastroenterological and liver disorders. PMID:19884893

7 CFR 51.3069 - Very serious damage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS) United States Standards for Florida Avocados Definitions § 51.3069 Very serious damage. Very... break very seriously affecting the appearance, or the edible or shipping quality; (b) Pulled stems when the skin surrounding the exposed stem cavity is torn more than an aggregate area of a circle one-half...

7 CFR 51.3069 - Very serious damage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS) United States Standards for Florida Avocados Definitions § 51.3069 Very serious damage. Very... break very seriously affecting the appearance, or the edible or shipping quality; (b) Pulled stems when the skin surrounding the exposed stem cavity is torn more than an aggregate area of a circle one-half...

Human Effector Memory T Helper Cells Engage with Mouse Macrophages and Cause Graft-versus-Host-Like Pathology in Skin of Humanized Mice Used in a Nonclinical Immunization Study.

PubMed

Sundarasetty, Balasai; Volk, Valery; Theobald, Sebastian J; Rittinghausen, Susanne; Schaudien, Dirk; Neuhaus, Vanessa; Figueiredo, Constanca; Schneider, Andreas; Gerasch, Laura; Mucci, Adele; Moritz, Thomas; von Kaisenberg, Constantin; Spineli, Loukia M; Sewald, Katherina; Braun, Armin; Weigt, Henning; Ganser, Arnold; Stripecke, Renata

2017-06-01

Humanized mice engrafted with human hematopoietic stem cells and developing functional human T-cell adaptive responses are in critical demand to test human-specific therapeutics. We previously showed that humanized mice immunized with long-lived induced-dendritic cells loaded with the pp65 viral antigen (iDCpp65) exhibited a faster development and maturation of T cells. Herein, we evaluated these effects in a long-term (36 weeks) nonclinical model using two stem cell donors to assess efficacy and safety. Relative to baseline, iDCpp65 immunization boosted the output of effector memory CD4 + T cells in peripheral blood and lymph nodes. No weight loss, human malignancies, or systemic graft-versus-host (GVH) disease were observed. However, for one reconstitution cohort, some mice immunized with iDCpp65 showed GVH-like signs on the skin. Histopathology analyses of the inflamed skin revealed intrafollicular and perifollicular human CD4 + cells near F4/80 + mouse macrophages around hair follicles. In spleen, CD4 + cells formed large clusters surrounded by mouse macrophages. In plasma, high levels of human T helper 2-type inflammatory cytokines were detectable, which activated in vitro the STAT5 pathway of murine macrophages. Despite this inflammatory pattern, human CD8 + T cells from mice with GVH reacted against the pp65 antigen in vitro. These results uncover a dynamic cross-species interaction between human memory T cells and mouse macrophages in the skin and lymphatic tissues of humanized mice. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Lower Oncogenic Potential of Human Mesenchymal Stem Cells Derived from Cord Blood Compared to Induced Pluripotent Stem Cells

PubMed Central

Foroutan, T.; Najmi, M.; Kazemi, N.; Hasanlou, M.; Pedram, A.

2015-01-01

Background: In regenerative medicine, use of each of the mesenchymal stem cells derived from bone marrow, cord blood, and adipose tissue, has several cons and pros. Mesenchymal stem cells derived from cord blood have been considered the best source for precursor transplantation. Direct reprogramming of a somatic cell into induced pluripotent stem cells by over-expression of 6 transcription factors Oct4, Sox2, Klf4, lin28, Nanog, and c-Myc has great potential for regenerative medicine, eliminating the ethical issues of embryonic stem cells and the rejection problems of using non-autologous cells. Objective: To compare reprogramming and pluripotent markers OCT4, Sox-2, c-Myc, Klf4, Nanog, and lin28 in mesenchymal stem cells derived from cord blood and induced pluripotent stem cells. Methods: We analyzed the expression level of OCT4, Sox-2, c-Myc, Klf4, Nanog and lin28 genes in human mesenchymal stem cells derived from cord blood and induced pluripotent stem cells by cell culture and RT-PCR. Results: The expression level of pluripotent genes OCT4 and Sox-2, Nanog and lin28 in mesenchymal stem cells derived from cord blood were significantly higher than those in induced pluripotent stem cells. In contrast to OCT-4A and Sox-2, Nanog and lin28, the expression level of oncogenic factors c-Myc and Klf4 were significantly higher in induced pluripotent stem cells than in mesenchymal stem cells derived from cord blood. Conclusion: It could be concluded that mesenchymal stem cells derived from human cord blood have lower oncogenic potential compared to induced pluripotent stem cells. PMID:26306155

Eckol suppresses maintenance of stemness and malignancies in glioma stem-like cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyun, Kyung-Hwan; Yoon, Chang-Hwan; Kim, Rae-Kwon

A subpopulation of cancer cells with stem cell properties is responsible for tumor maintenance and progression, and may contribute to resistance to anticancer treatments. Thus, compounds that target cancer stem-like cells could be usefully applied to destroy cancer. In this study, we investigated the effect of Eckol, a phlorotannin compound, on stemness and malignancies in glioma stem-like cells. To determine whether Eckol targets glioma stem-like cells, we examined whether Eckol treatment could change the expression levels of glioma stem-like cell markers and self-renewal-related proteins as well as the sphere forming ability, and the sensitivity to anticancer treatments. Alterations in themore » malignant properties of sphere-derived cells by Eckol were also investigated by soft-agar colony forming assay, by xenograft assay in nude mice, and by cell invasion assay. Treatment of sphere-forming glioma cells with Eckol effectively decreased the sphere formation as well as the CD133{sup +} cell population. Eckol treatment suppressed expression of the glioma stem-like cell markers and the self-renewal-related proteins without cell death. Moreover, treatment of glioma stem-like cells with Eckol significantly attenuated anchorage-independent growth on soft agar and tumor formation in xenograft mice. Importantly, Eckol treatment effectively reduced the resistance of glioma stem-like cells to ionizing radiation and temozolomide. Treatment of glioma stem-like cells with Eckol markedly blocked both phosphoinositide 3-kinase-Akt and Ras-Raf-1-Erk signaling pathways. These results indicate that the natural phlorotannin Eckol suppresses stemness and malignancies in glioma stem-like cells, and thereby makes glioma stem-like cells more sensitive to anticancer treatments, providing novel therapeutic strategies targeting specifically cancer stem-like cells.« less

Flagellin preconditioning enhances the efficacy of mesenchymal stem cells in an irradiation-induced proctitis model.

PubMed

Linard, Christine; Strup-Perrot, Carine; Lacave-Lapalun, Jean-Victor; Benderitter, Marc

2016-09-01

The success of mesenchymal stem cell transplantation for proctitis depends not only on cell donors but also on host microenvironmental factors, which play a major role in conditioning mesenchymal stem cell immunosuppressive action and repair. This study sought to determine if flagellin, a TLR5 ligand, can enhance the mesenchymal stem cell treatment efficacy in radiation-induced proctitis. With the use of a colorectal model of 27 Gy irradiation in rats, we investigated and compared the effects on immune capacity and remodeling at 28 d after irradiation of the following: 1) systemic mesenchymal stem cell (5 × 10(6)) administration at d 7 after irradiation, 2) administration of flagellin at d 3 and systemic mesenchymal stem cell administration at d 7, and 3) in vitro preconditioning of mesenchymal stem cells with flagellin, 24 h before their administration on d 7. The mucosal CD8(+) T cell population was normalized after treatment with flagellin-preconditioned mesenchymal stem cells or flagellin plus mesenchymal stem cells, whereas mesenchymal stem cells alone did not alter the radiation-induced elevation of CD8(+) T cell frequency. Mesenchymal stem cell treatment returned the irradiation-elevated frequency of CD25(+) cells in the mucosa-to-control levels, whereas both flagellin-preconditioned mesenchymal stem cell and flagellin-plus-mesenchymal stem cell treatment each significantly increased not only CD25(+) cell frequency but also forkhead box p3 and IL-2Rα expression. Specifically, IL-10 was overexpressed after flagellin-preconditioned mesenchymal stem cell treatment. Analysis of collagen expression showed that the collagen type 1/collagen type 3 ratio, an indicator of wound-healing maturation, was low in the irradiated and mesenchymal stem cell-treated groups and returned to the normal level only after the flagellin-preconditioned mesenchymal stem cell treatment. This was associated with a reduction in myofibroblast accumulation. In a proctitis model, flagellin-preconditioned mesenchymal stem cells improved colonic immune capacity and enhanced tissue remodeling. © Society for Leukocyte Biology.

MicroRNAs: key regulators of stem cells.

PubMed

Gangaraju, Vamsi K; Lin, Haifan

2009-02-01

The hallmark of a stem cell is its ability to self-renew and to produce numerous differentiated cells. This unique property is controlled by dynamic interplays between extrinsic signalling, epigenetic, transcriptional and post-transcriptional regulations. Recent research indicates that microRNAs (miRNAs) have an important role in regulating stem cell self-renewal and differentiation by repressing the translation of selected mRNAs in stem cells and differentiating daughter cells. Such a role has been shown in embryonic stem cells, germline stem cells and various somatic tissue stem cells. These findings reveal a new dimension of gene regulation in controlling stem cell fate and behaviour.

[Progress in epidermal stem cells].

PubMed

Wang, Li-Juan; Wang, You-Liang; Yang, Xiao

2010-03-01

Mammalian skin epidermis contains different epidermal stem cell pools which contribute to the homeostasis and repair of skin epithelium. Epidermal stem cells possess two essential features common to all stem cells: self-renewal and differentiation. Disturbing the balance between self-renewal and differentiation of epidermal stem cell often causes tumors or other skin diseases. Epidermal stem cell niches provide a special microenvironment that maintains a balance of stem cell quiescence and activity. This review primarily concentrates on the following points of the epidermal stem cells: the existing evidences, the self-renewal and differentiation, the division pattern, the signal pathways regulating self-renewal and differentiation, and the microenvironment (niche) and macroenvironment maintaining the homeostasis of stem cells.

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

PubMed

Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Amnion-derived stem cells: in quest of clinical applications

PubMed Central

2011-01-01

In the promising field of regenerative medicine, human perinatal stem cells are of great interest as potential stem cells with clinical applications. Perinatal stem cells could be isolated from normally discarded human placentae, which are an ideal cell source in terms of availability, the fewer number of ethical concerns, less DNA damage, and so on. Numerous studies have demonstrated that some of the placenta-derived cells possess stem cell characteristics like pluripotent differentiation ability, particularly in amniotic epithelial (AE) cells. Term human amniotic epithelium contains a relatively large number of stem cell marker-positive cells as an adult stem cell source. In this review, we introduce a model theory of why so many AE cells possess stem cell characteristics. We also describe previous work concerning the therapeutic applications and discuss the pluripotency of the AE cells and potential pitfalls for amnion-derived stem cell research. PMID:21596003

The role of stem cells in aesthetic surgery: fact or fiction?

PubMed

McArdle, Adrian; Senarath-Yapa, Kshemendra; Walmsley, Graham G; Hu, Michael; Atashroo, David A; Tevlin, Ruth; Zielins, Elizabeth; Gurtner, Geoffrey C; Wan, Derrick C; Longaker, Michael T

2014-08-01

Stem cells are attractive candidates for the development of novel therapies, targeting indications that involve functional restoration of defective tissue. Although most stem cell therapies are new and highly experimental, there are clinics around the world that exploit vulnerable patients with the hope of offering supposed stem cell therapies, many of which operate without credible scientific merit, oversight, or other patient protection. The authors review the potential and the drawbacks of incorporation of stem cells in cosmetic procedures. A review of U.S. Food and Drug Administration-approved indications and ongoing clinical trials with adipose stem cells is provided. Furthermore, a "snapshot" analysis of Web sites using the search terms "stem cell therapy" or "stem cell treatment" or "stem cell facelift" was performed. Despite the protective net cast by regulatory agencies such as the U.S. Food and Drug Administration and professional societies such as the American Society of Plastic Surgeons, the authors are witnessing worrying advertisements for procedures such as stem cell face lifts, stem cell breast augmentations, and even stem cell vaginal rejuvenation. The marketing and promotion of stem cell procedures in aesthetic surgery is not adequately supported by clinical evidence in the majority of cases. Stem cells offer tremendous potential, but the marketplace is saturated with unsubstantiated and sometimes fraudulent claims that may place patients at risk. With plastic surgeons at the forefront of stem cell-based regenerative medicine, it is critically important that they provide an example of a rigorous approach to research, data collection, and advertising of stem cell therapies.

Polymer microarray technology for stem cell engineering

PubMed Central

Coyle, Robert; Jia, Jia; Mei, Ying

2015-01-01

Stem cells hold remarkable promise for applications in tissue engineering and disease modeling. During the past decade, significant progress has been made in developing soluble factors (e.g., small molecules and growth factors) to direct stem cells into a desired phenotype. However, the current lack of suitable synthetic materials to regulate stem cell activity has limited the realization of the enormous potential of stem cells. This can be attributed to a large number of materials properties (e.g., chemical structures and physical properties of materials) that can affect stem cell fate. This makes it challenging to design biomaterials to direct stem cell behavior. To address this, polymer microarray technology has been developed to rapidly identify materials for a variety of stem cell applications. In this article, we summarize recent developments in polymer array technology and their applications in stem cell engineering. Statement of significance Stem cells hold remarkable promise for applications in tissue engineering and disease modeling. In the last decade, significant progress has been made in developing chemically defined media to direct stem cells into a desired phenotype. However, the current lack of the suitable synthetic materials to regulate stem cell activities has been limiting the realization of the potential of stem cells. This can be attributed to the number of variables in material properties (e.g., chemical structures and physical properties) that can affect stem cells. Polymer microarray technology has shown to be a powerful tool to rapidly identify materials for a variety of stem cell applications. Here we summarize recent developments in polymer array technology and their applications in stem cell engineering. PMID:26497624

Stem cells in kidney regeneration.

PubMed

Yokote, Shinya; Yokoo, Takashi

2012-01-01

Currently many efforts are being made to apply regenerative medicine to kidney diseases using several types of stem/progenitor cells, such as mesenchymal stem cells, renal stem/progenitor cells, embryonic stem cells and induced pluripotent stem cells. Stem cells have the ability to repair injured organs and ameliorate damaged function. The strategy for kidney tissue repair is the recruitment of stem cells and soluble reparative factors to the kidney to elicit tissue repair and the induction of dedifferentiation of resident renal cells. On the other hand, where renal structure is totally disrupted, absolute kidney organ regeneration is needed to rebuild a whole functional kidney. In this review, we describe current advances in stem cell research for kidney tissue repair and de novo organ regeneration.

Stem Cell Sciences plc.

PubMed

Daniels, Sebnem

2006-09-01

Stem Cell Sciences' core objective is to develop safe and effective stem cell-based therapies for currently incurable diseases. In order to achieve this goal, Stem Cell Sciences recognizes the need for multiple technologies and a globally integrated stem cell initiative. The key challenges for the successful application of stem cells in the clinic is the need for a reproducible supply of pure, fully characterized stem cells that have been grown in suitable conditions for use in the clinic.

Fusion with stem cell makes the hepatocellular carcinoma cells similar to liver tumor-initiating cells.

PubMed

Wang, Ran; Chen, Shuxun; Li, Changxian; Ng, Kevin Tak Pan; Kong, Chi-wing; Cheng, Jinping; Cheng, Shuk Han; Li, Ronald A; Lo, Chung Mau; Man, Kwan; Sun, Dong

2016-02-04

Cell fusion is a fast and highly efficient technique for cells to acquire new properties. The fusion of somatic cells with stem cells can reprogram somatic cells to a pluripotent state. Our research on the fusion of stem cells and cancer cells demonstrates that the fused cells can exhibit stemness and cancer cell-like characteristics. Thus, tumor-initiating cell-like cells are generated. We employed laser-induced single-cell fusion technique to fuse the hepatocellular carcinoma cells and human embryonic stem cells (hESC). Real-time RT-PCR, flow cytometry and in vivo tumorigenicity assay were adopted to identify the gene expression difference. We successfully produced a fused cell line that coalesces the gene expression information of hepatocellular carcinoma cells and stem cells. Experimental results showed that the fused cells expressed cancer and stemness markers as well as exhibited increased resistance to drug treatment and enhanced tumorigenesis. Fusion with stem cells transforms liver cancer cells into tumor initiating-like cells. Results indicate that fusion between cancer cell and stem cell may generate tumor initiating-like cells.

Stem cell-derived vascular endothelial cells and their potential application in regenerative medicine

USDA-ARS?s Scientific Manuscript database

Although a 'vascular stem cell' population has not been identified or generated, vascular endothelial and mural cells (smooth muscle cells and pericytes) can be derived from currently known pluripotent stem cell sources, including human embryonic stem cells and induced pluripotent stem cells. We rev...

Hematopoietic cell differentiation from embryonic and induced pluripotent stem cells

PubMed Central

2013-01-01

Pluripotent stem cells, both embryonic stem cells and induced pluripotent stem cells, are undifferentiated cells that can self-renew and potentially differentiate into all hematopoietic lineages, such as hematopoietic stem cells (HSCs), hematopoietic progenitor cells and mature hematopoietic cells in the presence of a suitable culture system. Establishment of pluripotent stem cells provides a comprehensive model to study early hematopoietic development and has emerged as a powerful research tool to explore regenerative medicine. Nowadays, HSC transplantation and hematopoietic cell transfusion have successfully cured some patients, especially in malignant hematological diseases. Owing to a shortage of donors and a limited number of the cells, hematopoietic cell induction from pluripotent stem cells has been regarded as an alternative source of HSCs and mature hematopoietic cells for intended therapeutic purposes. Pluripotent stem cells are therefore extensively utilized to facilitate better understanding in hematopoietic development by recapitulating embryonic development in vivo, in which efficient strategies can be easily designed and deployed for the generation of hematopoietic lineages in vitro. We hereby review the current progress of hematopoietic cell induction from embryonic stem/induced pluripotent stem cells. PMID:23796405

Stem Cell Basics

MedlinePlus

... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... Basics » Stem Cell Basics I. Back to top Stem Cell Basics I. Introduction: What are stem cells, and ...

TOPICAL REVIEW: Stem cells engineering for cell-based therapy

NASA Astrophysics Data System (ADS)

Taupin, Philippe

2007-09-01

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

From Banking to International Governance: Fostering Innovation in Stem Cell Research

PubMed Central

Isasi, Rosario; Knoppers, Bartha M.

2011-01-01

Stem cell banks are increasingly recognized as an essential resource of biological materials for both basic and translational stem cell research. By providing transnational access to quality controlled and ethically sourced stem cell lines, stem cell banks seek to foster international collaboration and innovation. However, given that national stem cell banks operate under different policy, regulatory and commercial frameworks, the transnational sharing of stem cell materials and data can be complicating. This paper will provide an overview of the most pressing challenges regarding the governance of stem cell banks, and the difficulties in designing regulatory and commercial frameworks that foster stem cell research. Moreover, the paper will shed light on the numerous international initiatives that have arisen to help harmonize and standardize stem cell banking and research processes to overcome such challenges. PMID:21904557

Stem Cells Transplantation in the Treatment of Patients with Liver Failure.

PubMed

Tao, Ya-Chao; Wang, Meng-Lan; Chen, En-Qiang; Tang, Hong

2018-02-23

Liver failure is a life-threatening liver disease encompassing severe acute deterioration of liver function. Emergency liver transplantation is the only curative treatment for liver failure, but is restricted by the severe shortage of organ donors. Stem cell, including embroyonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells and hepatic progenitor cells, have capacity to proliferate and differentiate and could be used in a variety of liver diseases including hereditary liver diseases, cirrhosis and liver failure. We summarized the basic experimental and clinical advances of stem cell transplantation in liver failure treatment, and also discussed the advantages and disadvantage of different stem cells subtype in this field, aiming to provide a perspective on the stem cell-based therapy for liver failure. Stem cells, especially mesenchymal stem cells (mainly low immunogenicity and paracrine characteristics) and induced pluripotent stem cells (generation of desired cell type from somatic cell), are feasible candidates for cell therapy in the treatment of liver failure, but there are some drawbacks remaining to be resolved, such as low engraftment, cryotpreservation methods and tumorigenesis. Stem cell transplantation is a promising but challenging strategy and paves a new way for curing liver failure. But more efforts need to be made to overcome problems before this new strategy could be safely and effectively applied to humans. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Recent Progress in Stem Cell Modification for Cardiac Regeneration

PubMed Central

Voronina, Natalia; Steinhoff, Gustav

2018-01-01

During the past decades, stem cell-based therapy has acquired a promising role in regenerative medicine. The application of novel cell therapeutics for the treatment of cardiovascular diseases could potentially achieve the ambitious aim of effective cardiac regeneration. Despite the highly positive results from preclinical studies, data from phase I/II clinical trials are inconsistent and the improvement of cardiac remodeling and heart performance was found to be quite limited. The major issues which cardiac stem cell therapy is facing include inefficient cell delivery to the site of injury, accompanied by low cell retention and weak effectiveness of remaining stem cells in tissue regeneration. According to preclinical and clinical studies, various stem cells (adult stem cells, embryonic stem cells, and induced pluripotent stem cells) represent the most promising cell types so far. Beside the selection of the appropriate cell type, researchers have developed several strategies to produce “second-generation” stem cell products with improved regenerative capacity. Genetic and nongenetic modifications, chemical and physical preconditioning, and the application of biomaterials were found to significantly enhance the regenerative capacity of transplanted stem cells. In this review, we will give an overview of the recent developments in stem cell engineering with the goal to facilitate stem cell delivery and to promote their cardiac regenerative activity. PMID:29535769

Eat, breathe, ROS: controlling stem cell fate through metabolism.

PubMed

Kubli, Dieter A; Sussman, Mark A

2017-05-01

Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered: Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary: The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes.

Eat, breathe, ROS: controlling stem cell fate through metabolism

PubMed Central

Kubli, Dieter A.; Sussman, Mark A.

2017-01-01

Introduction Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes. PMID:28406333

Therapeutic strategies involving uterine stem cells in reproductive medicine.

PubMed

Simoni, Michael; Taylor, Hugh S

2018-06-01

The current review provides an update on recent advances in stem cell biology relevant to female reproduction. Stem cells are undifferentiated cells that often serve as a reservoir of cells to regenerate tissue in settings or injury or cell loss. The endometrium has progenitor stem cells that can replace all of the endometrium during each menstrual cycle. In addition, multipotent endometrial cells replace these progenitor cells when depleted. Recruitment of stem cells from outside of the uterus occurs in setting of increased demand such as ischemia or injury. Bone marrow-derived multipotent stem cells are recruited to the uterus by estrogen or injury-induced expression of the chemokine CXCL12. In the setting of overwhelming injury, especially in the setting of low estrogen levels, there may be insufficient stem cell recruitment to adequately repair the uterus resulting in conditions such as Asherman syndrome or other endometrial defects. In contrast, excessive recruitment of stem cells underlies endometriosis. Enhanced understanding of stem-cell mobilization, recruitment, and engraftment has created the possibility of improved therapy for endometrial defects and endometriosis through enhanced manipulation of stem-cell trafficking. Further, the normal endometrium is a rich source of multipotent stem cells that can be used for numerous applications in regenerative medicine beyond reproduction. A better understanding of reproductive stem-cell biology may allow improved treatment of endometrial disease such as Asherman syndrome and other endometrial receptivity defects. Inhibiting stem-cell mobilization may also be helpful in endometriosis therapy. Finally, endometrial derived multipotent stem cells may play a crucial role in cell therapy for regenerative medicine.

Gene screening of Wharton's jelly derived stem cells.

PubMed

Mechiche Alami, S; Velard, F; Draux, F; Siu Paredes, F; Josse, J; Lemaire, F; Gangloff, S C; Graesslin, O; Laurent-Maquin, D; Kerdjoudj, H

2014-01-01

Stem cells are the most powerful candidate for the treatment of various diseases. Suitable stem cell source should be harvested with minimal invasive procedure, found in great quantity, and transplanted with no risk of immune response and tumor formation. Fetal derived stem cells have been introduced as an excellent alternative to adult and embryonic stem cells use, but unfortunately, their degree of "stemness" and molecular characterization is still unclear. Several studies have been performed deciphering whether fetal stem cells meet the needs of regenerative medicine. We believe that a transcriptomic screening of Wharton's jelly stem cells will bring insights on cell population features.

Stem Cell Banking for Regenerative and Personalized Medicine

PubMed Central

Harris, David T.

2014-01-01

Regenerative medicine, tissue engineering and gene therapy offer the opportunity to treat and cure many of today’s intractable afflictions. These approaches to personalized medicine often utilize stem cells to accomplish these goals. However, stem cells can be negatively affected by donor variables such as age and health status at the time of collection, compromising their efficacy. Stem cell banking offers the opportunity to cryogenically preserve stem cells at their most potent state for later use in these applications. Practical stem cell sources include bone marrow, umbilical cord blood and tissue, and adipose tissue. Each of these sources contains stem cells that can be obtained from most individuals, without too much difficulty and in an economical fashion. This review will discuss the advantages and disadvantages of each stem cell source, factors to be considered when contemplating banking each stem cell source, the methodology required to bank each stem cell source, and finally, current and future clinical uses of each stem cell source. PMID:28548060

Gingival Fibroblasts as Autologous Feeders for Induced Pluripotent Stem Cells.

PubMed

Yu, G; Okawa, H; Okita, K; Kamano, Y; Wang, F; Saeki, M; Yatani, H; Egusa, H

2016-01-01

Human gingival fibroblasts (hGFs) present an attractive source of induced pluripotent stem cells (iPSCs), which are expected to be a powerful tool for regenerative dentistry. However, problems to be addressed prior to clinical application include the use of animal-derived feeder cells for cultures. The aim of this study was to establish an autologous hGF-derived iPSC (hGF-iPSC) culture system by evaluating the feeder ability of hGFs. In both serum-containing and serum-free media, hGFs showed higher proliferation than human dermal fibroblasts (hDFs). Three hGF strains were isolated under serum-free conditions, although 2 showed impaired proliferation. When hGF-iPSCs were transferred onto mitomycin C-inactivated hGFs, hDFs, or mouse-derived SNL feeders, hGF and SNL feeders were clearly hGF-iPSC supportive for more than 50 passages, whereas hDF feeders were only able to maintain undifferentiated hGF-iPSC growth for a few passages. After 20 passages on hGF feeders, embryonic stem cell marker expression and CpG methylation at the NANOG and OCT3/4 promoters were similar for hGF-iPSCs cultured on hGF and SNL feeder cells. Long-term cultures of hGF-iPSCs on hGF feeders sustained their normal karyotype and pluripotency. On hGF feeders, hGF-iPSC colonies were surrounded by many colony-derived fibroblast-like cells, and the size of intact colonies at 7 d after passage was significantly larger than that on SNL feeders. Allogeneic hGF strains also maintained hGF-iPSCs for 10 passages. Compared with hDFs, hGFs showed a higher production of laminin-332, laminin α5 chain, and insulin-like growth factor-II, which have been reported to sustain the long-term self-renewal of pluripotent stem cells. These results suggest that hGFs possess an excellent feeder capability and thus can be used as alternatives to conventional mouse-derived SNL and hDF feeders. In addition, our findings suggest that hGF feeders are promising candidates for animal component-free ex vivo expansion of autologous hGF-iPSCs, thus providing an important step toward the future therapeutic application of hGF-iPSCs. © International & American Associations for Dental Research 2015.

Nine Things to Know About Stem Cell Treatments

MedlinePlus

... Toggle Nav Nine Things To Know About Stem Cell Treatments Home > Stem Cells and Medicine > Nine Things ... About Stem Cell Treatments Many clinics offering stem cell treatments make claims that are not supported by ...

Cancer (stem) cell differentiation: An inherent or acquired property?

PubMed

Mohr, Marieke; Zänker, Kurt S; Dittmar, Thomas

2015-12-01

There is a growing list of data indicating that cancer (stem) cells could functionally adapt foreign tissue features, such as endothelial-like cells or neuroendocrine cells, express lineage markers or could differentiate into various lineages in response to appropriate differentiation criteria. The finding that cancer (stem) cells may possess some kind of differentiation capacity poses the question whether this might be an inherent or acquired property. Cancer stem cells share stem cell characteristics and may thus possess an inherent differentiation capacity enabling the cells to respond to various differentiation stimuli. Considering the plasticity of cancer (stem) cells, even non-tumorigenic (and putatively non-differentiable) tumor cells could give rise to tumorigenic tumor stem cells, exhibiting stem cell characteristics including an inherent differentiation capacity. On the contrary, cancer (stem) cells may have acquired differentiation capacity as a consequence of a previous cell fusion event with cell types exhibiting differentiation potential and being fusogenic, such as macrophages or stem cells. Of pivotal interest in a tumor context are macrophages, which chiefly foster the chronically inflamed tumor microenvironment. Because chronically inflamed tissue is a well-known trigger for cell fusion and both macrophages and stem cells are highly fusogenic we conclude that cell fusion events between these cell types and cancer (stem) cells should frequently occur, thereby giving rise to hybrid cells exhibiting not only novel properties, like an enhanced metastatogenic phenotype, but also parental characteristics, such as differentiation capacity. Conceivably, the combination of both properties might be advantageous for metastasizing cancer (stem) cells to adapt better and faster to a foreign organ tissue environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sox10+ adult stem cells contribute to biomaterial encapsulation and microvascularization

PubMed Central

Wang, Dong; Wang, Aijun; Wu, Fan; Qiu, Xuefeng; Li, Ye; Chu, Julia; Huang, Wen-Chin; Xu, Kang; Gong, Xiaohua; Li, Song

2017-01-01

Implanted biomaterials and biomedical devices generally induce foreign body reaction and end up with encapsulation by a dense avascular fibrous layer enriched in extracellular matrix. Fibroblasts/myofibroblasts are thought to be the major cell type involved in encapsulation, but it is unclear whether and how stem cells contribute to this process. Here we show, for the first time, that Sox10+ adult stem cells contribute to both encapsulation and microvessel formation. Sox10+ adult stem cells were found sparsely in the stroma of subcutaneous loose connective tissues. Upon subcutaneous biomaterial implantation, Sox10+ stem cells were activated and recruited to the biomaterial scaffold, and differentiated into fibroblasts and then myofibroblasts. This differentiation process from Sox10+ stem cells to myofibroblasts could be recapitulated in vitro. On the other hand, Sox10+ stem cells could differentiate into perivascular cells to stabilize newly formed microvessels. Sox10+ stem cells and endothelial cells in three-dimensional co-culture self-assembled into microvessels, and platelet-derived growth factor had chemotactic effect on Sox10+ stem cells. Transplanted Sox10+ stem cells differentiated into smooth muscle cells to stabilize functional microvessels. These findings demonstrate the critical role of adult stem cells in tissue remodeling and unravel the complexity of stem cell fate determination. PMID:28071739

Tumor suppressors Sav/Scrib and oncogene Ras regulate stem cell transformation in adult Drosophila Malpighian Tubules

PubMed Central

Zeng, Xiankun; Singh, Shree Ram; Hou, David; Hou, Steven X.

2012-01-01

An increasing body of evidence suggests that tumors might originate from a few transformed cells that share many properties with normal stem cells. However, it remains unclear how normal stem cells are transformed into cancer stem cells. Here, we demonstrated that mutations causing the loss of tumor suppressor Sav or Scrib or activation of the oncogene Ras transform normal stem cells into cancer stem cells through a multistep process in the adult Drosophila Malpighian Tubules (MTs). In wild-type MTs, each stem cell generates one self-renewing and one differentiating daughter cell. However, in flies with loss-of-function sav or scrib or gain-of-function Ras mutations, both daughter cells grew and behaved like stem cells, leading to the formation of tumors in MTs. Ras functioned downstream of Sav and Scrib in regulating the stem cell transformation. The Ras-transformed stem cells exhibited many of the hallmarks of cancer, such as increased proliferation, reduced cell death, and failure to differentiate. We further demonstrated that several signal transduction pathways (including MEK/MAPK, RhoA, PKA, and TOR) mediate Rasṕ function in the stem cell transformation. Therefore, we have identified a molecular mechanism that regulates stem cell transformation, and this finding may lead to strategies for preventing tumor formation in certain organs. PMID:20432470

Molecular Dissection of Mesenchymal–Epithelial Interactions in the Hair Follicle

PubMed Central

Rendl, Michael; Lewis, Lisa

2005-01-01

De novo hair follicle formation in embryonic skin and new hair growth in adult skin are initiated when specialized mesenchymal dermal papilla (DP) cells send cues to multipotent epithelial stem cells. Subsequently, DP cells are enveloped by epithelial stem cell progeny and other cell types to form a niche orchestrating hair growth. Understanding the general biological principles that govern the mesenchymal–epithelial interactions within the DP niche, however, has been hampered so far by the lack of systematic approaches to dissect the complete molecular make-up of this complex tissue. Here, we take a novel multicolor labeling approach, using cell type–specific transgenic expression of red and green fluorescent proteins in combination with immunolabeling of specific antigens, to isolate pure populations of DP and four of its surrounding cell types: dermal fibroblasts, melanocytes, and two different populations of epithelial progenitors (matrix and outer root sheath cells). By defining their transcriptional profiles, we develop molecular signatures characteristic for the DP and its niche. Validating the functional importance of these signatures is a group of genes linked to hair disorders that have been largely unexplored. Additionally, the DP signature reveals novel signaling and transcription regulators that distinguish them from other cell types. The mesenchymal–epithelial signatures include key factors previously implicated in ectodermal-neural fate determination, as well as a myriad of regulators of bone morphogenetic protein signaling. These findings establish a foundation for future functional analyses of the roles of these genes in hair development. Overall, our strategy illustrates how knowledge of the genes uniquely expressed by each cell type residing in a complex niche can reveal important new insights into the biology of the tissue and its associated disease states. PMID:16162033

Mesenchymal Stem Cell Levels of Human Spinal Tissues.

PubMed

Harris, Liam; Vangsness, C Thomas

2018-05-01

Systematic review. The aim of this study was to investigate, quantify, compare, and compile the various mesenchymal stem cell (MSC) tissue sources within human spinal tissues to act as a compendium for clinical and research application. Recent years have seen a dramatic increase in academic and clinical understanding of human MSCs. Previously limited to cells isolated from bone marrow, the past decade has illicited the characterization and isolation of human MSCs from adipose, bone marrow, synovium, muscle, periosteum, peripheral blood, umbilical cord, placenta, and numerous other tissues. As researchers explore practical applications of cells in these tissues, the absolute levels of MSCs in specific spinal tissue will be critical to guide future research. The PubMED, MEDLINE, EMBASE, and Cochrane databases were searched for articles relating to the harvest, characterization, isolation, and quantification of human MSCs from spinal tissues. Selected articles were examined for relevant data, categorized according to type of spinal tissue, and when possible, standardized to facilitate comparisons between sites. Human MSC levels varied widely between spinal tissues. Yields for intervertebral disc demonstrated roughly 5% of viable cells to be positive for MSC surface markers. Cartilage endplate cells yielded 18,500 to 61,875 cells/0.8 mm thick sample of cartilage end plate. Ligamentum flavum yielded 250,000 to 500,000 cells/g of tissue. Annulus fibrosus fluorescence activated cell sorting treatment found 29% of cells positive for MSC marker Stro-1. Nucleus pulposus yielded mean tissue samples of 40,584 to 234,137 MSCs per gram of tissue. Numerous tissues within and surrounding the spine represent a consistent and reliable source for the harvest and isolation of human MSCs. Among the tissues of the spine, the annulus fibrosus and ligamentum flavum each offer considerable levels of MSCs, and may prove comparable to that of bone marrow. 5.

Structure and enzyme expression in photosynthetic organs of the atypical C4 grass Arundinella hirta.

PubMed

Wakayama, Masataka; Ohnishi, Jun-ichi; Ueno, Osamu

2006-05-01

In its leaf blade, Arundinella hirta has unusual Kranz cells that lie distant from the veins (distinctive cells; DCs), in addition to the usual Kranz units composed of concentric layers of mesophyll cells (MCs) and bundle sheath cells (BSCs; usual Kranz cells) surrounding the veins. We examined whether chlorophyllous organs other than leaf blades--namely, the leaf sheath, stem, scale leaf, and constituents of the spike--also have this unique anatomy and the C4 pattern of expression of photosynthetic enzymes. All the organs developed DCs to varying degrees, as well as BSCs. The stem, rachilla, and pedicel had C4-type anatomy with frequent occurrence of DCs, as in the leaf blade. The leaf sheath, glume, and scale leaf had a modified C4 anatomy with MCs more than two cells distant from the Kranz cells; DCs were relatively rare. An immunocytochemical study of C3 and C4 enzymes revealed that all the organs exhibited essentially the same C4 pattern of expression as in the leaf blade. In the scale leaf, however, intense expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) occurred in the MCs as well as in the BSCs and DCs. In the leaf sheath, the distant MCs also expressed Rubisco. In Arundinella hirta, it seems that the ratio of MC to Kranz cell volumes, and the distance from the Kranz cells, but not from the veins, affects the cellular expression of photosynthetic enzymes. We suggest that the main role of DCs is to keep a constant quantitative balance between the MCs and Kranz cells, which is a prerequisite for effective C4 pathway operation.

The king is dead, long live the king: entering a new era of stem cell research and clinical development.

PubMed

Ichim, Thomas; Riordan, Neil H; Stroncek, David F

2011-12-20

In mid November the biopharma industry was shocked by the announcement from Geron that they were ending work on embryonic stem cell research and therapy. For more than 10 years the public image of all stem cell research has been equated with embryonic stem cells. Unfortunately, a fundamentally important medical and financial fact was being ignored: embryonic stem cell therapy is extremely immature. In parallel to efforts in embryonic stem cell research and development, scientists and physicians in the field of adult stem cells realized that the natural role of adult stem cells in the body is to promote healing and to act like endogenous "repair cells" and, as a result, numerous companies have entered the field of adult stem cell therapy with the goal of expanding numbers of adult stem cells for administration to patients with various conditions. In contrast to embryonic stem cells, which are extremely expensive and potentially dangerous, adult cell cells are inexpensive and have an excellent safety record when used in humans. Many studies are now showing that adult stem cells are practical, patient-applicable, therapeutics that are very close to being available for incorporation into the practice of medicine. These events signal the entrance of the field of stem cells into a new era: an era where hype and misinformation no longer triumph over economic and medical realities.

On the Origin of Cancer Metastasis

PubMed Central

Seyfried, Thomas N.; Huysentruyt, Leanne C.

2013-01-01

Metastasis involves the spread of cancer cells from the primary tumor to surrounding tissues and to distant organs and is the primary cause of cancer morbidity and mortality. In order to complete the metastatic cascade, cancer cells must detach from the primary tumor, intravasate into the circulatory and lymphatic systems, evade immune attack, extravasate at distant capillary beds, and invade and proliferate in distant organs. Currently, several hypotheses have been advanced to explain the origin of cancer metastasis. These involve an epithelial mesenchymal transition, an accumulation of mutations in stem cells, a macrophage facilitation process, and a macrophage origin involving either transformation or fusion hybridization with neoplastic cells. Many of the properties of metastatic cancer cells are also seen in normal macrophages. A macrophage origin of metastasis can also explain the long-standing “seed and soil” hypothesis and the absence of metastasis in plant cancers. The view of metastasis as a macrophage metabolic disease can provide novel insight for therapeutic management. PMID:23237552

Control of stem cell fate by engineering their micro and nanoenvironment

PubMed Central

Griffin, Michelle F; Butler, Peter E; Seifalian, Alexander M; Kalaskar, Deepak M

2015-01-01

Stem cells are capable of long-term self-renewal and differentiation into specialised cell types, making them an ideal candidate for a cell source for regenerative medicine. The control of stem cell fate has become a major area of interest in the field of regenerative medicine and therapeutic intervention. Conventional methods of chemically inducing stem cells into specific lineages is being challenged by the advances in biomaterial technology, with evidence highlighting that material properties are capable of driving stem cell fate. Materials are being designed to mimic the clues stem cells receive in their in vivo stem cell niche including topographical and chemical instructions. Nanotopographical clues that mimic the extracellular matrix (ECM) in vivo have shown to regulate stem cell differentiation. The delivery of ECM components on biomaterials in the form of short peptides sequences has also proved successful in directing stem cell lineage. Growth factors responsible for controlling stem cell fate in vivo have also been delivered via biomaterials to provide clues to determine stem cell differentiation. An alternative approach to guide stem cells fate is to provide genetic clues including delivering DNA plasmids and small interfering RNAs via scaffolds. This review, aims to provide an overview of the topographical, chemical and molecular clues that biomaterials can provide to guide stem cell fate. The promising features and challenges of such approaches will be highlighted, to provide directions for future advancements in this exciting area of stem cell translation for regenerative medicine. PMID:25621104

Multipotent Stem Cell and Reproduction.

PubMed

Khanlarkhani, Neda; Baazm, Maryam; Mohammadzadeh, Farzaneh; Najafi, Atefeh; Mehdinejadiani, Shayesteh; Sobhani, Aligholi

Stem cells are self-renewing and undifferentiated cell types that can be differentiate into functional cells. Stem cells can be classified into two main types based on their source of origin: Embryonic and Adult stem cells. Stem cells also classified based on the range of differentiation potentials into Totipotent, Pluripotent, Multipotent, and Unipotent. Multipotent stem cells have the ability to differentiate into all cell types within one particular lineage. There are plentiful advantages and usages for multipotent stem cells. Multipotent Stem cells act as a significant key in procedure of development, tissue repair, and protection. The accessibility and adaptability of these amazing cells create them a great therapeutic choice for different part of medical approaches, and it becomes interesting topic in the scientific researches to found obvious method for the most advantageous use of MSC-based therapies. Recent studies in the field of stem cell biology have provided new perspectives and opportunities for the treatment of infertility disorders.

Strategies to improve homing of mesenchymal stem cells for greater efficacy in stem cell therapy.

PubMed

Naderi-Meshkin, Hojjat; Bahrami, Ahmad Reza; Bidkhori, Hamid Reza; Mirahmadi, Mahdi; Ahmadiankia, Naghmeh

2015-01-01

Stem/progenitor cell-based therapeutic approach in clinical practice has been an elusive dream in medical sciences, and improvement of stem cell homing is one of major challenges in cell therapy programs. Stem/progenitor cells have a homing response to injured tissues/organs, mediated by interactions of chemokine receptors expressed on the cells and chemokines secreted by the injured tissue. For improvement of directed homing of the cells, many techniques have been developed either to engineer stem/progenitor cells with higher amount of chemokine receptors (stem cell-based strategies) or to modulate the target tissues to release higher level of the corresponding chemokines (target tissue-based strategies). This review discusses both of these strategies involved in the improvement of stem cell homing focusing on mesenchymal stem cells as most frequent studied model in cellular therapies. © 2014 International Federation for Cell Biology.

College Students' Conceptions of Stem Cells, Stem Cell Research, and Cloning

ERIC Educational Resources Information Center

Concannon, James P.; Siegel, Marcelle A.; Halverson, Kristy; Freyermuth, Sharyn

2010-01-01

In this study, we examined 96 undergraduate non-science majors' conceptions of stem cells, stem cell research, and cloning. This study was performed at a large, Midwest, research extensive university. Participants in the study were asked to answer 23 questions relating to stem cells, stem cell research, and cloning in an on-line assessment before…

Stem cell biobanks.

PubMed

Bardelli, Silvana

2010-04-01

Stem cells contribute to innate healing and harbor a promising role for regenerative medicine. Stem cell banking through long-term storage of different stem cell platforms represents a fundamental source to preserve original features of stem cells for patient-specific clinical applications. Stem cell research and clinical translation constitute fundamental and indivisible modules catalyzed through biobanking activity, generating a return of investment.

Muscle Stem Cells: A Model System for Adult Stem Cell Biology.

PubMed

Cornelison, Ddw; Perdiguero, Eusebio

2017-01-01

Skeletal muscle stem cells, originally termed satellite cells for their position adjacent to differentiated muscle fibers, are absolutely required for the process of skeletal muscle repair and regeneration. In the last decade, satellite cells have become one of the most studied adult stem cell systems and have emerged as a standard model not only in the field of stem cell-driven tissue regeneration but also in stem cell dysfunction and aging. Here, we provide background in the field and discuss recent advances in our understanding of muscle stem cell function and dysfunction, particularly in the case of aging, and the potential involvement of muscle stem cells in genetic diseases such as the muscular dystrophies.

Redox regulation of plant stem cell fate.

PubMed

Zeng, Jian; Dong, Zhicheng; Wu, Haijun; Tian, Zhaoxia; Zhao, Zhong

2017-10-02

Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen peroxide (H 2 O 2 ) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS-metabolizing enzymes. The superoxide anion (O2·-) is markedly enriched in stem cells to activate WUSCHEL and maintain stemness, whereas H 2 O 2 is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, H 2 O 2 negatively regulates O2·- biosynthesis in stem cells, and increasing H 2 O 2 levels or scavenging O2·- leads to the termination of stem cells. Our results provide a mechanistic framework for ROS-mediated control of plant stem cell fate and demonstrate that the balance between O2·- and H 2 O 2 is key to stem cell maintenance and differentiation. © 2017 The Authors.

Ocular Stem Cell Research from Basic Science to Clinical Application: A Report from Zhongshan Ophthalmic Center Ocular Stem Cell Symposium

PubMed Central

Ouyang, Hong; Goldberg, Jeffrey L.; Chen, Shuyi; Li, Wei; Xu, Guo-Tong; Li, Wei; Zhang, Kang; Nussenblatt, Robert B.; Liu, Yizhi; Xie, Ting; Chan, Chi-Chao; Zack, Donald J.

2016-01-01

Stem cells hold promise for treating a wide variety of diseases, including degenerative disorders of the eye. The eye is an ideal organ for stem cell therapy because of its relative immunological privilege, surgical accessibility, and its being a self-contained system. The eye also has many potential target diseases amenable to stem cell-based treatment, such as corneal limbal stem cell deficiency, glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa (RP). Among them, AMD and glaucoma are the two most common diseases, affecting over 200 million people worldwide. Recent results on the clinical trial of retinal pigment epithelial (RPE) cells from human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) in treating dry AMD and Stargardt’s disease in the US, Japan, England, and China have generated great excitement and hope. This marks the beginning of the ocular stem cell therapy era. The recent Zhongshan Ophthalmic Center Ocular Stem Cell Symposium discussed the potential applications of various stem cell types in stem cell-based therapies, drug discoveries and tissue engineering for treating ocular diseases. PMID:27102165

Bioengineered Systems and Designer Matrices That Recapitulate the Intestinal Stem Cell Niche.

PubMed

Wang, Yuli; Kim, Raehyun; Hinman, Samuel S; Zwarycz, Bailey; Magness, Scott T; Allbritton, Nancy L

2018-03-01

The relationship between intestinal stem cells (ISCs) and the surrounding niche environment is complex and dynamic. Key factors localized at the base of the crypt are necessary to promote ISC self-renewal and proliferation, to ultimately provide a constant stream of differentiated cells to maintain the epithelial barrier. These factors diminish as epithelial cells divide, migrate away from the crypt base, differentiate into the postmitotic lineages, and end their life span in approximately 7 days when they are sloughed into the intestinal lumen. To facilitate the rapid and complex physiology of ISC-driven epithelial renewal, in vivo gradients of growth factors, extracellular matrix, bacterial products, gases, and stiffness are formed along the crypt-villus axis. New bioengineered tools and platforms are available to recapitulate various gradients and support the stereotypical cellular responses associated with these gradients. Many of these technologies have been paired with primary small intestinal and colonic epithelial cells to re-create select aspects of normal physiology or disease states. These biomimetic platforms are becoming increasingly sophisticated with the rapid discovery of new niche factors and gradients. These advancements are contributing to the development of high-fidelity tissue constructs for basic science applications, drug screening, and personalized medicine applications. Here, we discuss the direct and indirect evidence for many of the important gradients found in vivo and their successful application to date in bioengineered in vitro models, including organ-on-chip and microfluidic culture devices.

Genetic Basis of Inherited Macular Dystrophies and Implications for Stem Cell Therapy

PubMed Central

Mellough, Carla B; Steel, David HW; Lako, Majlinda

2009-01-01

Untreatable hereditary macular dystrophy (HMD) presents a major burden to society in terms of the resulting patient disability and the cost to the healthcare provision system. HMD results in central vision loss in humans sufficiently severe for blind registration, and key issues in the development of therapeutic strategies to target these conditions are greater understanding of the causes of photoreceptor loss and the development of restorative procedures. More effective and precise analytical techniques coupled to the development of transgenic models of disease have led to a prolific growth in the identification and our understanding of the genetic mutations that underly HMD. Recent successes in driving differentiation of pluripotent cells towards specific somatic lineages have led to the development of more efficient protocols that can yield enriched populations of a desired phenotype. Retinal pigmented epithelial cells and photoreceptors derived from these are some of the most promising cells that may soon be used in the treatment of specific HMD, especially since rapid developments in the field of induced pluripotency have now set the stage for the production of patient-derived stem cells that overcome the ethical and methodological issues surrounding the use of embryonic derivatives. In this review we highlight a selection of HMD which appear suitable candidates for combinatorial restorative therapy, focusing specifically on where those photoreceptor loss occurs. This technology, along with increased genetic screening, opens up an entirely new pathway to restore vision in patients affected by HMD. PMID:19551904

StemTextSearch: Stem cell gene database with evidence from abstracts.

PubMed

Chen, Chou-Cheng; Ho, Chung-Liang

2017-05-01

Previous studies have used many methods to find biomarkers in stem cells, including text mining, experimental data and image storage. However, no text-mining methods have yet been developed which can identify whether a gene plays a positive or negative role in stem cells. StemTextSearch identifies the role of a gene in stem cells by using a text-mining method to find combinations of gene regulation, stem-cell regulation and cell processes in the same sentences of biomedical abstracts. The dataset includes 5797 genes, with 1534 genes having positive roles in stem cells, 1335 genes having negative roles, 1654 genes with both positive and negative roles, and 1274 with an uncertain role. The precision of gene role in StemTextSearch is 0.66, and the recall is 0.78. StemTextSearch is a web-based engine with queries that specify (i) gene, (ii) category of stem cell, (iii) gene role, (iv) gene regulation, (v) cell process, (vi) stem-cell regulation, and (vii) species. StemTextSearch is available through http://bio.yungyun.com.tw/StemTextSearch.aspx. Copyright © 2017. Published by Elsevier Inc.

Application of Stem Cell Technology in Dental Regenerative Medicine.

PubMed

Feng, Ruoxue; Lengner, Chistopher

2013-07-01

In this review, we summarize the current literature regarding the isolation and characterization of dental tissue-derived stem cells and address the potential of these cell types for use in regenerative cell transplantation therapy. Looking forward, platforms for the delivery of stem cells via scaffolds and the use of growth factors and cytokines for enhancing dental stem cell self-renewal and differentiation are discussed. We aim to understand the developmental origins of dental tissues in an effort to elucidate the molecular pathways governing the genesis of somatic dental stem cells. The advantages and disadvantages of several dental stem cells are discussed, including the developmental stage and specific locations from which these cells can be purified. In particular, stem cells from human exfoliated deciduous teeth may act as a very practical and easily accessibly reservoir for autologous stem cells and hold the most value in stem cell therapy. Dental pulp stem cells and periodontal ligament stem cells should also be considered for their triple lineage differentiation ability and relative ease of isolation. Further, we address the potentials and limitations of induced pluripotent stem cells as a cell source in dental regenerative. From an economical and a practical standpoint, dental stem cell therapy would be most easily applied in the prevention of periodontal ligament detachment and bone atrophy, as well as in the regeneration of dentin-pulp complex. In contrast, cell-based tooth replacement due to decay or other oral pathology seems, at the current time, an untenable approach.

The UK Stem Cell Bank: a UK government-funded, international resource center for stem cell research.

PubMed

Stacey, Glyn; Hunt, Charles J

2006-01-01

The UK Stem Cell Bank is a UK Research Council-funded initiative that aims to provide ethically sourced and quality controlled stocks of cells for researchers and also establish seed stocks of cell lines for clinical trials. Whilst the Bank is prohibited from carrying out basic stem cell research (to avoid conflicts of interest) it is working to improve stem cell banking procedures including cryopreservation, characterization and quality control. The Bank also supports training activities and has provided the hub for the International Stem Cell Initiative, which includes 17 expert stem cell centers aiming to characterize a large number of human embryonic stem cell lines in a standardized way to improve our understanding of the characteristics of these cells.

Methods for Stem Cell Production and Therapy

NASA Technical Reports Server (NTRS)

Valluri, Jagan V. (Inventor); Claudio, Pier Paolo (Inventor)

2015-01-01

The present invention relates to methods for rapidly expanding a stem cell population with or without culture supplements in simulated microgravity conditions. The present invention relates to methods for rapidly increasing the life span of stem cell populations without culture supplements in simulated microgravity conditions. The present invention also relates to methods for increasing the sensitivity of cancer stem cells to chemotherapeutic agents by culturing the cancer stem cells under microgravity conditions and in the presence of omega-3 fatty acids. The methods of the present invention can also be used to proliferate cancer cells by culturing them in the presence of omega-3 fatty acids. The present invention also relates to methods for testing the sensitivity of cancer cells and cancer stem cells to chemotherapeutic agents by culturing the cancer cells and cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce tissue for use in transplantation by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors to promote differentiation of cancer stem cells under microgravity conditions.

Dental pulp stem cells in regenerative dentistry.

PubMed

Casagrande, Luciano; Cordeiro, Mabel M; Nör, Silvia A; Nör, Jacques E

2011-01-01

Stem cells constitute the source of differentiated cells for the generation of tissues during development, and for regeneration of tissues that are diseased or injured postnatally. In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that span from Alzheimer's disease to cardiac ischemia to bone or tooth loss. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental pulp is considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that dental pulp stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. The dental pulp stem cells are highly proliferative. This characteristic facilitates ex vivo expansion and enhances the translational potential of these cells. Notably, the dental pulp is arguably the most accessible source of postnatal stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental pulp an attractive source of mesenchymal stem cells for tissue regeneration. This review discusses fundamental concepts of stem cell biology and tissue engineering within the context of regenerative dentistry.

Translating stem cell therapies: the role of companion animals in regenerative medicine

PubMed Central

Volk, Susan W.; Theoret, Christine

2013-01-01

Veterinarians and veterinary medicine have been integral to the development of stem cell therapies. The contributions of large animal experimental models to the development and refinement of modern hematopoietic stem cell transplantation were noted nearly five decades ago. More recent advances in adult stem cell/regenerative cell therapies continue to expand knowledge of the basic biology and clinical applications of stem cells. A relatively liberal legal and ethical regulation of stem cell research in veterinary medicine has facilitated the development and in some instances clinical translation of a variety of cell-based therapies involving hematopoietic (HSC) and mesenchymal stem cells (MSC) as well as other adult regenerative cells and recently embryonic stem cells (ESC) and induced pluripotent stem cells (iPSC). In fact, many of the pioneering developments in these fields of stem cell research have been achieved through collaborations of veterinary and human scientists. This review aims to provide an overview of the contribution of large animal veterinary models in advancing stem cell therapies for both human and clinical veterinary applications. Moreover, in the context of the “One Health Initiative”, the role veterinary patients may play in the future evolution of stem cell therapies for both human and animal patients will be explored. PMID:23627495

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche

PubMed Central

2018-01-01

ABSTRACT Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. PMID:29361569

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche.

PubMed

Wang, Xiaoxi; Page-McCaw, Andrea

2018-02-07

Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. © 2018. Published by The Company of Biologists Ltd.

21st Nantes Actualités Transplantation: "When Stem Cells Meet Immunology".

PubMed

Anegon, Ignacio; Nguyen, Tuan Huy

2017-01-01

"When Stem Cells Meet Immunology" has been the topic of the 21st annual "Nantes Actualités en Transplantation" meeting (June 9-10, 2016, Nantes, France). This meeting brought together pioneers and leading experts in the fields of stem cells, biomaterials and immunoregulation. Presentations covered multipotent (mesenchymal and hematopoietic) and pluripotent stem cells (embryonic and induced) for regenerative medicine of incurable diseases, immunotherapy and blood transfusions. An additional focus had been immune rejections and responses of allogeneic or autologous stem cells. Conversely, stem cells are also able to directly modulate the immune response through the production of immunoregulatory molecules. Moreover, stem cells may also provide an unlimited source of immune cells (DCs, NK cells, B cells, and T cells) that can operate as "super" immune cells, for example, through genetic engineering with chimeric antigen receptors.This meeting report puts presentations into an overall context highlighting new potential biomarkers for potency prediction of mesenchymal stem cell-derived and pluripotent stem cell-derived multicellular organoids. Finally, we propose future directions arising from the flourishing encounter of stem cell and immune biology.

Differential sensitivity of Glioma stem cells to Aurora kinase A inhibitors: implications for stem cell mitosis and centrosome dynamics.

PubMed

Mannino, Mariella; Gomez-Roman, Natividad; Hochegger, Helfrid; Chalmers, Anthony J

2014-07-01

Glioma stem-cell-like cells are considered to be responsible for treatment resistance and tumour recurrence following chemo-radiation in glioblastoma patients, but specific targets by which to kill the cancer stem cell population remain elusive. A characteristic feature of stem cells is their ability to undergo both symmetric and asymmetric cell divisions. In this study we have analysed specific features of glioma stem cell mitosis. We found that glioma stem cells appear to be highly prone to undergo aberrant cell division and polyploidization. Moreover, we discovered a pronounced change in the dynamic of mitotic centrosome maturation in these cells. Accordingly, glioma stem cell survival appeared to be strongly dependent on Aurora A activity. Unlike differentiated cells, glioma stem cells responded to moderate Aurora A inhibition with spindle defects, polyploidization and a dramatic increase in cellular senescence, and were selectively sensitive to Aurora A and Plk1 inhibitor treatment. Our study proposes inhibition of centrosomal kinases as a novel strategy to selectively target glioma stem cells. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Effect of aging on stem cells

PubMed Central

Ahmed, Abu Shufian Ishtiaq; Sheng, Matilda HC; Wasnik, Samiksha; Baylink, David J; Lau, Kin-Hing William

2017-01-01

Pluripotent stem cells have the remarkable self-renewal ability and are capable of differentiating into multiple diverse cells. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging-associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging-associated diseases. This review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging-associated stem cell defects. PMID:28261550

Engineering Stem Cells for Biomedical Applications

PubMed Central

Yin, Perry T.; Han, Edward

2018-01-01

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. PMID:25772134

Therapeutic potential of dental stem cells

PubMed Central

Chalisserry, Elna Paul; Nam, Seung Yun; Park, Sang Hyug; Anil, Sukumaran

2017-01-01

Stem cell biology has become an important field in regenerative medicine and tissue engineering therapy since the discovery and characterization of mesenchymal stem cells. Stem cell populations have also been isolated from human dental tissues, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla, dental follicle progenitor cells, and periodontal ligament stem cells. Dental stem cells are relatively easily obtainable and exhibit high plasticity and multipotential capabilities. The dental stem cells represent a gold standard for neural-crest-derived bone reconstruction in humans and can be used for the repair of body defects in low-risk autologous therapeutic strategies. The bioengineering technologies developed for tooth regeneration will make substantial contributions to understand the developmental process and will encourage future organ replacement by regenerative therapies in a wide variety of organs such as the liver, kidney, and heart. The concept of developing tooth banking and preservation of dental stem cells is promising. Further research in the area has the potential to herald a new dawn in effective treatment of notoriously difficult diseases which could prove highly beneficial to mankind in the long run. PMID:28616151

Single-cell sequencing in stem cell biology.

PubMed

Wen, Lu; Tang, Fuchou

2016-04-15

Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of stem cell populations, but these differences are masked when bulk cells are used for omic analysis. Single-cell sequencing technologies serve as powerful tools to dissect cellular heterogeneity comprehensively and to identify distinct phenotypic cell types, even within a 'homogeneous' stem cell population. These technologies, including single-cell genome, epigenome, and transcriptome sequencing technologies, have been developing rapidly in recent years. The application of these methods to different types of stem cells, including pluripotent stem cells and tissue-specific stem cells, has led to exciting new findings in the stem cell field. In this review, we discuss the recent progress as well as future perspectives in the methodologies and applications of single-cell omic sequencing technologies.

The Implications of the Cancer Stem Cell Hypothesis for Neuro-Oncology and Neurology.

PubMed

Rich, Jeremy N

2008-05-01

The cancer stem cell hypothesis posits that cancers contain a subset of neoplastic cells that propagate and maintain tumors through sustained self-renewal and potent tumorigenecity. Recent excitement has been generated by a number of reports that have demonstrated the existence of cancer stem cells in several types of brain tumors. Brain cancer stem cells - also called tumor initiating cells or tumor propagating cells - share features with normal neural stem cells but do not necessarily originate from stem cells. Although most cancers have only a small fraction of cancer stem cells, these tumor cells have been shown in laboratory studies to contribute to therapeutic resistance, formation of new blood vessels to supply the tumor, and tumor spread. As malignant brain tumors rank among the deadliest of all neurologic diseases, the identification of new cellular targets may have profound implications in neuro-oncology. Novel drugs that target stem cell pathways active in brain tumors have been efficacious against cancer stem cells suggesting that anti-cancer stem cell therapies may advance brain tumor therapy. The cancer stem cell hypothesis may have several implications for other neurologic diseases as caution must be exercised in activating stem cell maintenance pathways in cellular therapies for neurodegenerative diseases. The ability for a small fraction of cells to determine the overall course of a disease may also inform new paradigms of disease that may translate into improved patient outcomes.

Can bone marrow differentiate into renal cells?

PubMed

Imai, Enyu; Ito, Takahito

2002-10-01

A considerable plasticity of adult stem cells has been confirmed in a wide variety of tissues. In particular, the pluripotency of bone marrow-derived stem cells may influence the regeneration of injured tissues and may provide novel avenues in regenerative medicine. Bone marrow contains at least hematopoietic and mesenchymal stem cells, and both can differentiate into a wide range of differentiated cells. Side population (SP) cells, which are originally defined in bone marrow cells by high efflux of DNA-binding dye, seem to be a new class of multipotent stem cells. Irrespective of the approach used to obtain stem cells, the fates of marrow-derived cells following bone marrow transplantation can be traced by labeling donor cells with green fluorescence protein or by identifying donor Y chromosome in female recipients. So far, bone marrow-derived cells have been reported to differentiate into renal cells, including mesangial cells, endothelial cells, podocytes, and tubular cells in the kidney, although controversy exists. Further studies are required to address this issue. Cell therapy will be promising when we learn to control stem cells such as bone marrow-derived stem cells, embryonic stem cells, and resident stem cells in the kidney. Identification of factors that support stem cells or promote their differentiation should provide a relevant step towards cell therapy.

Dynamics of vesicles in electric fields

NASA Astrophysics Data System (ADS)

Vlahovska, Petia; Gracia, Ruben

2007-11-01

Electromechanical forces are widely used for cell manipulation. Knowledge of the physical mechanisms underlying the interaction of cells and external fields is essential for practical applications. Vesicles are model cells made of a lipid bilayer membrane. They are examples of ``soft'' particles, i.e., their shape when subjected to flow or electric field is not given a priori but it is governed by the balance of membrane, fluid and electrical stresses. This generic ``softness'' gives rise to a very complex vesicle dynamics in external fields. In an AC electric field, as the frequency is increased, vesicles filled with a fluid less conducting than the surrounding fluid undergo shape transition from prolate to oblate ellipsoids. The opposite effect is observed with drops. We present an electro- hydrodynamic theory based on the leaky dielectric model that quantitatively describes experimental observations. We compare drops and vesicles, and show how their distinct behavior stems from different interfacial properties.

[The emerging technology of tissue engineering : Focus on stem cell niche].

PubMed

Schlötzer-Schrehardt, U; Freudenberg, U; Kruse, F E

2017-04-01

Limbal stem cells reside in a highly specialized complex microenvironment that is known as the stem cell niche, an anatomically protected region at the bottom of the Palisades of Vogt, where the stem cells are located and where their quiescence, proliferation and differentiation are maintained in balance. Besides the epithelial stem and progenitor cell clusters, the limbal niche comprises several types of supporting niche cells and a specific extracellular matrix mediating biochemical and biophysical signals. Stem cell-based tissue engineering aims to mimic the native stem cell niche and to present appropriate microenvironmental cues in a controlled and reproducible fashion in order to maintain stem cell function within the graft. Current therapeutic approaches for ex vivo expansion of limbal stem cells only take advantage of surrogate niches. However, new insights into the molecular composition of the limbal niche and innovative biosynthetic scaffolds have stimulated novel strategies for niche-driven stem cell cultivation. Promising experimental approaches include collagen-based organotypic coculture systems of limbal epithelial stem cells with their niche cells and biomimetic hydrogel platforms prefunctionalized with appropriate biomolecular and biophysical signals. Future translation of these novel regenerative strategies into clinical application is expected to improve long-term outcomes of limbal stem cell transplantation for ocular surface reconstruction.

Combination cell therapy with mesenchymal stem cells and neural stem cells for brain stroke in rats.

PubMed

Hosseini, Seyed Mojtaba; Farahmandnia, Mohammad; Razi, Zahra; Delavari, Somayeh; Shakibajahromi, Benafsheh; Sarvestani, Fatemeh Sabet; Kazemi, Sepehr; Semsar, Maryam

2015-05-01

Brain stroke is the second most important events that lead to disability and morbidity these days. Although, stroke is important, there is no treatment for curing this problem. Nowadays, cell therapy has opened a new window for treating central nervous system disease. In some previous studies the Mesenchymal stem cells and neural stem cells. In this study, we have designed an experiment to assess the combination cell therapy (Mesenchymal and Neural stem cells) effects on brain stroke. The Mesenchymal stem cells were isolated from adult rat bone marrow and the neural stem cells were isolated from ganglion eminence of rat embryo 14 days. The Mesenchymal stem cells were injected 1 day after middle cerebral artery occlusion (MCAO) and the neural stem cells transplanted 7 day after MCAO. After 28 days, the neurological outcomes and brain lesion volumes were evaluated. Also, the activity of Caspase 3 was assessed in different groups. The group which received combination cell therapy had better neurological examination and less brain lesion. Also the combination cell therapy group had the least Caspase 3 activity among the groups. The combination cell therapy is more effective than Mesenchymal stem cell therapy and neural stem cell therapy separately in treating the brain stroke in rats.

Application of Stem Cells in Oral Disease Therapy: Progresses and Perspectives

PubMed Central

Yang, Bo; Qiu, Yi; Zhou, Niu; Ouyang, Hong; Ding, Junjun; Cheng, Bin; Sun, Jianbo

2017-01-01

Stem cells are undifferentiated and pluripotent cells that can differentiate into specialized cells with a more specific function. Stem cell therapies become preferred methods for the treatment of multiple diseases. Oral and maxillofacial defect is one kind of the diseases that could be most possibly cured by stem cell therapies. Here we discussed oral diseases, oral adult stem cells, iPS cells, and the progresses/challenges/perspectives of application of stem cells for oral disease treatment. PMID:28421002

Diploid, but not haploid, human embryonic stem cells can be derived from microsurgically repaired tripronuclear human zygotes

PubMed Central

Fan, Yong; Li, Rong; Huang, Jin; Yu, Yang; Qiao, Jie

2013-01-01

Human embryonic stem cells have shown tremendous potential in regenerative medicine, and the recent progress in haploid embryonic stem cells provides new insights for future applications of embryonic stem cells. Disruption of normal fertilized embryos remains controversial; thus, the development of a new source for human embryonic stem cells is important for their usefulness. Here, we investigated the feasibility of haploid and diploid embryo reconstruction and embryonic stem cell derivation using microsurgically repaired tripronuclear human zygotes. Diploid and haploid zygotes were successfully reconstructed, but a large proportion of them still had a tripolar spindle assembly. The reconstructed embryos developed to the blastocyst stage, although the loss of chromosomes was observed in these zygotes. Finally, triploid and diploid human embryonic stem cells were derived from tripronuclear and reconstructed zygotes (from which only one pronucleus was removed), but haploid human embryonic stem cells were not successfully derived from the reconstructed zygotes when two pronuclei were removed. Both triploid and diploid human embryonic stem cells showed the general characteristics of human embryonic stem cells. These results indicate that the lower embryo quality resulting from abnormal spindle assembly contributed to the failure of the haploid embryonic stem cell derivation. However, the successful derivation of diploid embryonic stem cells demonstrated that microsurgical tripronuclear zygotes are an alternative source of human embryonic stem cells. In the future, improving spindle assembly will facilitate the application of triploid zygotes to the field of haploid embryonic stem cells. PMID:23255130

Transcriptome Response to Embolism Formation in Stems of Populus trichocarpa Provides Insight into Signaling and the Biology of Refilling1[W][OA

PubMed Central

Secchi, Francesca; Gilbert, Matthew E.; Zwieniecki, Maciej A.

2011-01-01

The mechanism of embolism repair in transpiring plants is still not understood, despite significant scientific effort. The refilling process is crucial to maintaining stem transport capacity and ensuring survival for plants experiencing dynamic changes in water stress. Refilling air-filled xylem vessels requires an energy and water source that can only be provided by adjacent living parenchyma cells. Here, we report an analysis of the transcriptome response of xylem parenchyma cells after embolism formation in Populus trichocarpa trees. Genes encoding aquaporins, ion transporters, and carbohydrate metabolic pathways were up-regulated, and there was a significant reduction in the expression of genes responding to oxidative stress. Thus, a novel view of the plant response to embolism emerges that suggests a role for oxygen in embolized vessels as a signal triggering xylem refilling and for the activity of cation transport as having a significant role in the generation of the energy gradient necessary to heal embolized vessels. These findings redefine current hypotheses surrounding the refilling phenomenon and provide insight into the complexity of the biological response to the seemingly simple physical event of xylem embolism formation. PMID:21951466

Nano scaffolds and stem cell therapy in liver tissue engineering

NASA Astrophysics Data System (ADS)

Montaser, Laila M.; Fawzy, Sherin M.

2015-08-01

Tissue engineering and regenerative medicine have been constantly developing of late due to the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Although stem cells hold great potential for the treatment of many injuries and degenerative diseases, several obstacles must be overcome before their therapeutic application can be realized. These include the development of advanced techniques to understand and control functions of micro environmental signals and novel methods to track and guide transplanted stem cells. A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. The application of nanotechnology to stem cell biology would be able to address those challenges. Combinations of stem cell therapy and nanotechnology in tissue engineering and regenerative medicine have achieved significant advances. These combinations allow nanotechnology to engineer scaffolds with various features to control stem cell fate decisions. Fabrication of Nano fiber cell scaffolds onto which stem cells can adhere and spread, forming a niche-like microenvironment which can guide stem cells to proceed to heal damaged tissues. In this paper, current and emergent approach based on stem cells in the field of liver tissue engineering is presented for specific application. The combination of stem cells and tissue engineering opens new perspectives in tissue regeneration for stem cell therapy because of the potential to control stem cell behavior with the physical and chemical characteristics of the engineered scaffold environment.

Stem-Cell-Based Tumorigenesis in Adult Drosophila.

PubMed

Hou, S X; Singh, S R

2017-01-01

Recent studies suggest that a small subset of cells within a tumor, the so-called cancer stem cells (CSCs), are responsible for tumor propagation, relapse, and the eventual death of most cancer patients. CSCs may derive from a few tumor-initiating cells, which are either transformed normal stem cells or reprogrammed differentiated cells after acquiring initial cancer-causing mutations. CSCs and normal stem cells share some properties, but CSCs differ from normal stem cells in their tumorigenic ability. Notably, CSCs are usually resistant to chemo- and radiation therapies. Despite the apparent roles of CSCs in human cancers, the biology underlying their behaviors remains poorly understood. Over the past few years, studies in Drosophila have significantly contributed to this new frontier of cancer research. Here, we first review how stem-cell tumors are initiated and propagated in Drosophila, through niche appropriation in the posterior midgut and through stem-cell competition for niche occupancy in the testis. We then discuss the differences between normal and tumorigenic stem cells, revealed by studying Ras V12 -transformed stem-cell tumors in the Drosophila kidney. Finally, we review the biology behind therapy resistance, which has been elucidated through studies of stem-cell resistance and sensitivity to death inducers using female germline stem cells and intestinal stem cells of the posterior midgut. We expect that screens using adult Drosophila neoplastic stem-cell tumor models will be valuable for identifying novel and effective compounds for treating human cancers. © 2017 Elsevier Inc. All rights reserved.

Stem cells with potential to generate insulin producing cells in man.

PubMed

Zulewski, Henryk

2006-10-14

Replacement of insulin-producing cells represents an almost ideal treatment for patients with diabetes mellitus type 1. Transplantation of pancreatic islets of Langerhans--although successful in experienced centres--is limited by the lack of donor organs. Generation of insulin-producing cells from stem cells represents an attractive alternative. Stem cells with the potential to differentiate into insulin-producing cells include embryonic stem cells (ESC) as well as adult stem cells from various tissues including the pancreas, liver, central nervous system, bone marrow and adipose tissue. The use of human ESC is hampered by ethical concerns and the inability to create patient specific ESC with therapeutic cloning. Among adult stem cells mesenchymal stem cells appear to have a particular developmental plasticity ex vivo that include their ability to adopt a pancreatic endocrine phenotype. The present review summarises the current knowledge on the development of insulin-producing cells from stem cells with special emphasis on human mesenchymal stem cells isolated from the pancreas and adipose tissue.

Stem cells with potential to generate insulin-producing cells in man.

PubMed

Zulewski, Henryk

2007-03-02

Replacement of insulin-producing cells represents an almost ideal treatment for patients with diabetes mellitus type 1. Transplantation of pancreatic islets of Langerhans--although successful in experienced centres--is limited by the lack of donor organs. Generation of insulin-producing cells from stem cells represents an attractive alternative. Stem cells with the potential to differentiate into insulin-producing cells include embryonic stem cells (ESC) as well as adult stem cells from various tissues including the pancreas, liver, central nervous system, bone marrow and adipose tissue. The use of human ESC is hampered by ethical concerns and the inability to create patient specific ESC with therapeutic cloning. Among adult stem cells mesenchymal stem cells appear to have a particular developmental plasticity ex vivo that include their ability to adopt a pancreatic endocrine phenotype. The present review summarises the current knowledge on the development of insulin-producing cells from stem cells with special emphasis on human mesenchymal stem cells isolated from the pancreas and adipose tissue.

Mechanical forces direct stem cell behaviour in development and regeneration

PubMed Central

Vining, Kyle H.; Mooney, David J.

2018-01-01

Stem cells and their local microenvironment, or niche, communicate through mechanical, cues to regulate cell fate and cell behaviour, and to guide developmental processes. During embryonic development, mechanical forces are involved in patterning and organogenesis. The physical environment of pluripotent stem cells regulates their differentiation and self-renewal. Mechanical and physical cues are also important in adult tissues, where adult stem cells require physical interactions with the extracellular matrix to maintain their potency. In vitro, synthetic models of the stem cell niche can be used to precisely control and manipulate the biophysical and biochemical properties of the stem cell microenvironment and examine how the mode and magnitude of mechanical cues, such as matrix stiffness or applied forces, direct stem cell differentiation and function. Fundamental insights on the mechanobiology of stem cells also inform the design of artificial niches to support stem cells for regenerative therapies. PMID:29115301

Recent Advances towards the Clinical Application of Stem Cells for Retinal Regeneration

PubMed Central

Becker, Silke; Jayaram, Hari; Limb, G. Astrid

2012-01-01

Retinal degenerative diseases constitute a major cause of irreversible blindness in the world. Stem cell-based therapies offer hope for these patients at risk of or suffering from blindness due to the deterioration of the neural retina. Various sources of stem cells are currently being investigated, ranging from human embryonic stem cells to adult-derived induced pluripotent stem cells as well as human Müller stem cells, with the first clinical trials to investigate the safety and tolerability of human embryonic stem cell-derived retinal pigment epithelium cells having recently commenced. This review aims to summarize the latest advances in the development of stem cell strategies for the replacement of retinal neurons and their supportive cells, the retinal pigment epithelium (RPE) affected by retinal degenerative conditions. Particular emphasis will be given to the advances in stem cell transplantation and the challenges associated with their translation into clinical practice. PMID:24710533

A switch in the mode of Wnt signaling orchestrates the formation of germline stem cell differentiation niche in Drosophila

PubMed Central

Upadhyay, Maitreyi; Kuna, Michael; Tudor, Sara; Martino Cortez, Yesenia

2018-01-01

Germline stem cell (GSC) self-renewal and differentiation into gametes is regulated by both intrinsic factors in the germ line as well as extrinsic factors from the surrounding somatic niche. dWnt4, in the escort cells of the adult somatic niche promotes GSC differentiation using the canonical β-catenin-dependent transcriptional pathway to regulate escort cell survival, adhesion to the germ line and downregulation of self-renewal signaling. Here, we show that in addition to the β-catenin-dependent canonical pathway, dWnt4 also uses downstream components of the Wnt non-canonical pathway to promote escort cell function earlier in development. We find that the downstream non-canonical components, RhoA, Rac1 and cdc42, are expressed at high levels and are active in escort cell precursors of the female larval gonad compared to the adult somatic niche. Consistent with this expression pattern, we find that the non-canonical pathway components function in the larval stages but not in adults to regulate GSC differentiation. In the larval gonad, dWnt4, RhoA, Rac1 and cdc42 are required to promote intermingling of escort cell precursors, a function that then promotes proper escort cell function in the adults. We find that dWnt4 acts by modulating the activity of RhoA, Rac1 and cdc42, but not their protein levels. Together, our results indicate that at different points of development, dWnt4 switches from using the non-canonical pathway components to using a β-catenin-dependent canonical pathway in the escort cells to facilitate the proper differentiation of GSCs. PMID:29370168

Generation of insulin-producing cells from rat mesenchymal stem cells using an aminopyrrole derivative XW4.4.

PubMed

Ouyang, Jingfeng; Huang, Wei; Yu, Wanwan; Xiong, Wei; Mula, Ramanjaneya V R; Zou, Hongbin; Yu, Yongping

2014-02-05

Type 1 diabetes mellitus (T1DM), a multisystem disease with both biochemical and anatomical/structural consequences, is a major health concern worldwide. Pancreatic islet transplantation provides a promising treatment for T1DM. However, the limited availability of islet tissue or new sources of insulin producing cells (IPCs) that are responsive to glucose hinder this promising approach. Though slow, the development of pancreatic beta-cell lines from rodent or human origin has been steadily progressing. Bone marrow-derived mesenchymal stem cells (MSCs) are multipotent, culture-expanded, non-hematopoietic cells that are currently being investigated as a novel cellular therapy. The in vitro differentiation potential of IPCs has raised hopes for a treatment of clinical diseases associated with autoimmunity. We screened for small molecules that induce pancreatic differentiation of IPCs. There are some compounds which showed positive effects on the DTZ staining. The aminopyrrole derivative compound XW4.4 which shows the best activity among them was found to induce pancreatic differentiation of rat MSCs (rMSCs). The in vitro studies indicated that treatment of rMSCs with compound XW4.4 resulted in differentiated cells with characteristics of IPCs including islet-like clusters, spherical, grape-like morphology, insulin secretion, positive for dithizone, glucose stimulation and expression of pancreatic endocrine cell marker genes. The data has also suggested that hepatocyte nuclear factor 3β (HNF 3β) may be involved in pancreatic differentiation of rMSCs when treated with XW4.4. Results indicate that XW4.4 induced rMSCs support the efforts to derive functional IPCs and serve as a means to alleviate limitations surrounding islet cell transplantation in the treatment of T1DM. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Cell plasticity and heterogeneity in cancer.

PubMed

Marjanovic, Nemanja D; Weinberg, Robert A; Chaffer, Christine L

2013-01-01

Heterogeneity within a given cancer arises from diverse cell types recruited to the tumor and from genetic and/or epigenetic differences amongst the cancer cells themselves. These factors conspire to create a disease with various phenotypes. There are 2 established models of cancer development and progression to metastatic disease. These are the clonal evolution and cancer stem cell models. The clonal evolution theory suggests that successive mutations accumulating in a given cell generate clonal outgrowths that thrive in response to microenvironmental selection pressures, dictating the phenotype of the tumor. The alternative cancer stem cell (CSC) model suggests that cancer cells with similar genetic backgrounds can be hierarchically organized according to their tumorigenic potential. Accordingly, CSCs reside at the apex of the hierarchy and are thought to possess the majority of a cancer's tumor-initiating and metastatic ability. A defining feature of this model is its apparent unidirectional nature, whereby CSCs undergo symmetric division to replenish the CSC pool and irreversible asymmetric division to generate daughter cells (non-CSCs) with low tumorigenic potential. However, evolving evidence supports a new model of tumorigenicity, in which considerable plasticity exists between the non-CSC and CSC compartments, such that non-CSCs can reacquire a CSC phenotype. These findings suggest that some tumors may adhere to a plastic CSC model, in which bidirectional conversions are common and essential components of tumorigenicity. Accumulating evidence surrounding the plasticity of cancer cells, in particular, suggests that aggressive CSCs can be created de novo within a tumor. Given the current focus on therapeutic targeting of CSCs, we discuss the implications of non-CSC-to-CSC conversions on the development of future therapies. © 2012 American Association for Clinical Chemistry

Stem-Cell Therapy Advances in China.

PubMed

Hu, Lei; Zhao, Bin; Wang, Songlin

2018-02-01

Stem-cell therapy is a promising method for treating patients with a wide range of diseases and injuries. Increasing government funding of scientific research has promoted rapid developments in stem-cell research in China, as evidenced by the substantial increase in the number and quality of publications in the past 5 years. Multiple high-quality studies have been performed in China that concern cell reprogramming, stem-cell homeostasis, gene modifications, and immunomodulation. The number of translation studies, including basic and preclinical investigations, has also increased. Around 100 stem-cell banks have been established in China, 10 stem-cell drugs are currently in the approval process, and >400 stem cell-based clinical trials are currently registered in China. With continued state funding, advanced biotechnical support, and the development of regulatory standards for the clinical application of stem cells, further innovations are expected that will lead to a boom in stem-cell therapies. This review highlights recent achievements in stem-cell research in China and discusses future prospects.

New insights into mechanisms of stem cell daughter fate determination in regenerative tissues.

PubMed

Sada, Aiko; Tumbar, Tudorita

2013-01-01

Stem cells can self-renew and differentiate over extended periods of time. Understanding how stem cells acquire their fates is a central question in stem cell biology. Early work in Drosophila germ line and neuroblast showed that fate choice is achieved by strict asymmetric divisions that can generate each time one stem and one differentiated cell. More recent work suggests that during homeostasis, some stem cells can divide symmetrically to generate two differentiated cells or two identical stem cells to compensate for stem cell loss that occurred by direct differentiation or apoptosis. The interplay of all these factors ensures constant tissue regeneration and the maintenance of stem cell pool size. This interplay can be modeled as a population-deterministic dynamics that, at least in some systems, may be described as stochastic behavior. Here, we overview recent progress made on the characterization of stem cell dynamics in regenerative tissues. Copyright © 2013 Elsevier Inc. All rights reserved.

Sensing of substratum rigidity and directional migration by fast-crawling cells

NASA Astrophysics Data System (ADS)

Okimura, Chika; Sakumura, Yuichi; Shimabukuro, Katsuya; Iwadate, Yoshiaki

2018-05-01

Living cells sense the mechanical properties of their surrounding environment and respond accordingly. Crawling cells detect the rigidity of their substratum and migrate in certain directions. They can be classified into two categories: slow-moving and fast-moving cell types. Slow-moving cell types, such as fibroblasts, smooth muscle cells, mesenchymal stem cells, etc., move toward rigid areas on the substratum in response to a rigidity gradient. However, there is not much information on rigidity sensing in fast-moving cell types whose size is ˜10 μ m and migration velocity is ˜10 μ m /min . In this study, we used both isotropic substrata with different rigidities and an anisotropic substratum that is rigid on the x axis but soft on the y axis to demonstrate rigidity sensing by fast-moving Dictyostelium cells and neutrophil-like differentiated HL-60 cells. Dictyostelium cells exerted larger traction forces on a more rigid isotropic substratum. Dictyostelium cells and HL-60 cells migrated in the "soft" direction on the anisotropic substratum, although myosin II-null Dictyostelium cells migrated in random directions, indicating that rigidity sensing of fast-moving cell types differs from that of slow types and is induced by a myosin II-related process.

Sensing of substratum rigidity and directional migration by fast-crawling cells.

PubMed

Okimura, Chika; Sakumura, Yuichi; Shimabukuro, Katsuya; Iwadate, Yoshiaki

2018-05-01

Living cells sense the mechanical properties of their surrounding environment and respond accordingly. Crawling cells detect the rigidity of their substratum and migrate in certain directions. They can be classified into two categories: slow-moving and fast-moving cell types. Slow-moving cell types, such as fibroblasts, smooth muscle cells, mesenchymal stem cells, etc., move toward rigid areas on the substratum in response to a rigidity gradient. However, there is not much information on rigidity sensing in fast-moving cell types whose size is ∼10 μm and migration velocity is ∼10 μm/min. In this study, we used both isotropic substrata with different rigidities and an anisotropic substratum that is rigid on the x axis but soft on the y axis to demonstrate rigidity sensing by fast-moving Dictyostelium cells and neutrophil-like differentiated HL-60 cells. Dictyostelium cells exerted larger traction forces on a more rigid isotropic substratum. Dictyostelium cells and HL-60 cells migrated in the "soft" direction on the anisotropic substratum, although myosin II-null Dictyostelium cells migrated in random directions, indicating that rigidity sensing of fast-moving cell types differs from that of slow types and is induced by a myosin II-related process.

Selection of Phage Display Peptides Targeting Human Pluripotent Stem Cell-Derived Progenitor Cell Lines.

PubMed

Bignone, Paola A; Krupa, Rachel A; West, Michael D; Larocca, David

2016-01-01

The ability of human pluripotent stem cells (hPS) to both self-renew and differentiate into virtually any cell type makes them a promising source of cells for cell-based regenerative therapies. However, stem cell identity, purity, and scalability remain formidable challenges that need to be overcome for translation of pluripotent stem cell research into clinical applications. Directed differentiation from hPS cells is inefficient and residual contamination with pluripotent cells that have the potential to form tumors remains problematic. The derivation of scalable (self-renewing) embryonic progenitor stem cell lines offers a solution because they are well defined and clonally pure. Clonally pure progenitor stem cell lines also provide a means for identifying cell surface targeting reagents that are useful for identification, tracking, and repeated derivation of the corresponding progenitor stem cell types from additional hPS cell sources. Such stem cell targeting reagents can then be applied to the manufacture of genetically diverse banks of human embryonic progenitor cell lines for drug screening, disease modeling, and cell therapy. Here we present methods to identify human embryonic progenitor stem cell targeting peptides by selection of phage display libraries on clonal embryonic progenitor cell lines and demonstrate their use for targeting quantum dots (Qdots) for stem cell labeling.

Extinction models for cancer stem cell therapy

PubMed Central

Sehl, Mary; Zhou, Hua; Sinsheimer, Janet S.; Lange, Kenneth L.

2012-01-01

Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth–death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives. PMID:22001354

Extinction models for cancer stem cell therapy.

PubMed

Sehl, Mary; Zhou, Hua; Sinsheimer, Janet S; Lange, Kenneth L

2011-12-01

Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth-death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives. Copyright © 2011 Elsevier Inc. All rights reserved.

Aging and stem cell therapy: AMPK as an applicable pharmacological target for rejuvenation of aged stem cells and achieving higher efficacy in stem cell therapy.

PubMed

Khorraminejad-Shirazi, Mohammadhossein; Farahmandnia, Mohammad; Kardeh, Bahareh; Estedlal, Alireza; Kardeh, Sina; Monabati, Ahmad

2017-10-19

In recent years, tissue regeneration has become a promising field for developing stem cell-based transplantation therapies for human patients. Adult stem cells are affected by the same aging mechanisms that involve somatic cells. One of the mechanisms involved in cellular aging is hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and disruption of 5' adenosine monophosphate-activated protein kinase (AMPK). Aging of stem cells results in their impaired regenerative capacity and depletion of stem cell pools in adult tissue, which results in lower efficacy of stem cell therapy. By utilizing an effective therapeutic intervention for aged stem cells, stem cell therapy can become more promising for future application. mTORC1 inhibition is a practical approach to preserve the stem cell pool. In this article, we review the dynamic interaction between sirtuin (silent mating type information regulation 2 homolog) 1, AMPK, and mTORC1. We propose that using AMPK activators such as 5-aminoimidazole-4-carboxamide ribonucleotide, A769662, metformin, and oxidized nicotinamide adenine dinucleotide (NAD + ) are practical ways to be employed for achieving better optimized results in stem cell-based transplantation therapies. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Stemness of spermatogonial stem cells encapsulated in alginate hydrogel during cryopreservation.

PubMed

Pirnia, A; Parivar, K; Hemadi, M; Yaghmaei, P; Gholami, M

2017-06-01

This study investigated the effect of spermatogonial stem cell encapsulated in alginate hydrogel during cryopreservation, as cells were protected against damage during cryopreservation within the hydrogel. Spermatogonial stem cells were isolated from the testes of Balb/c mice pups (6 days old), purified in laminin-coated dishes and CD90.1 microbeads, encapsulated in alginate hydrogel and then cryopreserved. After thawing, cell viability and Spermatogonial stem cell (SSC) colony diameter were evaluated. After RNA was isolated and cDNA was synthesised, the expression of stemness genes was considered using RT real-time PCR. Finally, spermatogonial stem cells labelled with BrdU were transplanted to busulfan azoospermic mouse models. Lin28a and Sall4 genes were significantly upregulated after cryopreservation in alginate hydrogel. However, cell viability was significantly decreased. The diameter of colonies consisting of spermatogonial stem cells freeze-thawed in alginate microbeads showed no significant difference with fresh spermatogonial stem cells and the control group. The injection of freeze-thawed spermatogonial stem cells encapsulated in alginate hydrogel resulted in spermatogenesis recovery. Alginate mimics the extracellular matrices (ECM) for spermatogonial stem cells; therefore, it can support stemness potential during the cell cryopreservation process and restart spermatogenesis after transplantation. © 2016 Blackwell Verlag GmbH.

Normal and cancer mammary stem cells evade interferon-induced constraint through the miR-199a-LCOR Axis

PubMed Central

Celià-Terrassa, Toni; Liu, Daniel; Choudhury, Abrar; Hang, Xiang; Wei, Yong; Zamalloa, Jose; Alfaro-Aco, Raymundo; Chakrabarti, Rumela; Jiang, Yi-Zhou; Koh, Bong Ihn; Smith, Heath; DeCoste, Christina; Li, Jun-Jing; Shao, Zhi-Ming; Kang, Yibin

2017-01-01

Tumor-initiating cells (TICs), or cancer stem cells (CSC), possess stem cell-like properties observed in normal adult tissue stem cells. Normal and cancerous stem cells may therefore share regulatory mechanisms for maintaining self-renewing capacity and resisting differentiation elicited by cell-intrinsic or microenvironmental cues. Here, we show that miR-199a promotes stem cell properties in mammary stem cells (MaSCs) and breast CSCs by directly repressing nuclear receptor corepressor LCOR, which primes interferon (IFN) responses. Elevated miR-199a expression in stem cell-enriched populations protects normal and malignant stem-like cells from differentiation and senescence induced by IFNs that are produced by epithelial and immune cells in the mammary gland. Importantly, the miR-199a-LCOR-IFN axis is activated in poorly differentiated ER− breast tumors, functionally promotes tumor initiation and metastasis, and is associated with poor clinical outcome. Our study therefore reveals a common mechanism shared by normal and malignant stem cells to protect them from suppressive immune cytokine signaling. PMID:28530657

The Role of Epithelial-Mesenchymal Transition in the Formation of Normal and Neoplastic Mammary Epithelial Stem Cells

DTIC Science & Technology

2011-09-01

separating stem cell and non- stem cell populations of normal and breast cancer cells and identified EMT transcription factors most likely involved in... stem cell biology. Preliminary results directly demonstrate that transient induction of EMT increases the number of mammary epithelial stem cells...EMT and entrance into a stem - cell state. The outcome of these experiments holds important implications for the mechanisms controlling the formation of

Role of the Stem Cell Niche in Hormone-Induced Tumorigenesis in Fetal Mouse Mammary Epithelium

DTIC Science & Technology

2005-08-01

responsive, self renewing and pluripotent. A structure specialized to contain and regulate stem cell activity has been structurally and molecularly...described in Drosophila and some mammalian tissues. The structure, the stem cell niche, functions to 1) shield the stem cell from the burden of incoming...directing stem cell renewal and maturation, 3) prevent stem cells from wandering through the tissue and producing new cells inappropriately, 4) prevent

The Effect of Laser Irradiation on Adipose Derived Stem Cell Proliferation and Differentiation

NASA Astrophysics Data System (ADS)

Abrahamse, H.; de Villiers, J.; Mvula, B.

2009-06-01

There are two fundamental types of stem cells: Embryonic Stem cells and Adult Stem cells. Adult Stem cells have a more restricted potential and can usually differentiate into a few different cell types. In the body these cells facilitate the replacement or repair of damaged or diseased cells in organs. Low intensity laser irradiation was shown to increase stem cell migration and stimulate proliferation and it is thought that treatment of these cells with laser irradiation may increase the stem cell harvest and have a positive effect on the viability and proliferation. Our research is aimed at determining the effect of laser irradiation on differentiation of Adipose Derived Stem Cells (ADSCs) into different cell types using a diode laser with a wavelength of 636 nm and at 5 J/cm2. Confirmation of stem cell characteristics and well as subsequent differentiation were assessed using Western blot analysis and cellular morphology supported by fluorescent live cell imaging. Functionality of subsequent differentiated cells was confirmed by measuring adenosine triphosphate (ATP) production and cell viability.

Alpha-fetoprotein, stem cells and cancer: how study of the production of alpha-fetoprotein during chemical hepatocarcinogenesis led to reaffirmation of the stem cell theory of cancer.

PubMed

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein during development, in response to liver injury and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas. When the cellular changes in these processes were compared to that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue-determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as normal tissues: stem cells, transit-amplifying cells and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, antiangiogenesis and differentiation therapy) are directed against the cancer transit-amplifying cells. When these therapies are discontinued, the cancer reforms from the cancer stem cells. Therapy directed toward interruption of the cell signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of regrowth of the cancer. Copyright 2008 S. Karger AG, Basel.

ALPHA-FETOPROTEIN (AFP), STEM CELLS, AND CANCER: HOW STUDY OF THE PRODUCTION OF AFP DURING CHEMICAL HEPATOCARCINOGENESIS LED TO REAFFIRMATION OF THE STEM CELL THEORY OF CANCER

PubMed Central

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein (AFP) during development, in response to liver injury, and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas (HCC). When the cellular changes in these processes were compared that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as do normal tissues: stem cells, transit-amplifying cells, and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, anti-angiogenesis and differentiation therapy) are directed against the cancer transit amplifying cells. When these therapies are discontinued, the cancer re-forms from the cancer stem cells. Therapy directed toward interruption of the cell-signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of re-growth of the cancer. PMID:18612221

A Comparative Transcriptomic Analysis Reveals Conserved Features of Stem Cell Pluripotency in Planarians and Mammals

PubMed Central

Labbé, Roselyne M.; Irimia, Manuel; Currie, Ko W.; Lin, Alexander; Zhu, Shu Jun; Brown, David D.R.; Ross, Eric J.; Voisin, Veronique; Bader, Gary D.; Blencowe, Benjamin J.; Pearson, Bret J.

2014-01-01

Many long-lived species of animals require the function of adult stem cells throughout their lives. However, the transcriptomes of stem cells in invertebrates and vertebrates have not been compared, and consequently, ancestral regulatory circuits that control stem cell populations remain poorly defined. In this study, we have used data from high-throughput RNA sequencing to compare the transcriptomes of pluripotent adult stem cells from planarians with the transcriptomes of human and mouse pluripotent embryonic stem cells. From a stringently defined set of 4,432 orthologs shared between planarians, mice and humans, we identified 123 conserved genes that are ≥5-fold differentially expressed in stem cells from all three species. Guided by this gene set, we used RNAi screening in adult planarians to discover novel stem cell regulators, which we found to affect the stem cell-associated functions of tissue homeostasis, regeneration, and stem cell maintenance. Examples of genes that disrupted these processes included the orthologs of TBL3, PSD12, TTC27, and RACK1. From these analyses, we concluded that by comparing stem cell transcriptomes from diverse species, it is possible to uncover conserved factors that function in stem cell biology. These results provide insights into which genes comprised the ancestral circuitry underlying the control of stem cell self-renewal and pluripotency. PMID:22696458

Investigating the mincing method for isolation of adipose-derived stem cells from pregnant women fat.

PubMed

Li, Yuan-Sheng; Chen, Pao-Jen; Wu, Li-Wei; Chou, Pei-Wen; Sun, Li-Yi; Chiou, Tzyy-Wen

2018-02-01

The success of stem cell application in regenerative medicine, usually require a stable source of stem or progenitor cells. Fat tissue represents a good source of stem cells because it is rich in stem cells and there are fewer ethical issues related to the use of such stem cells, unlike embryonic stem cells. Therefore, there has been increased interest in adipose-derived stem cells (ADSCs) for tissue engineering applications. Here, we aim to provide an easy processing method for isolating adult stem cells from human adipose tissue harvested from the subcutaneous fat of the abdominal wall during gynecologic surgery. We used a homogenizer to mince fat and compared the results with those obtained from the traditional cut method involving a sterile scalpel and forceps. Our results showed that our method provides another stable and quality source of stem cells that could be used in cases with a large quantity of fat. Furthermore, we found that pregnancy adipose-derived stem cells (P-ADSCs) could be maintained in vitro for extended periods with a stable population doubling and low senescence levels. P-ADSCs could also differentiate in vitro into adipogenic, osteogenic, chondrogenic, and insulin-producing cells in the presence of lineage-specific induction factors. In conclusion, like human lipoaspirates, adipose tissues obtained from pregnant women contain multipotent cells with better proliferation and showed great promise for use in both stem cell banking studies as well as in stem cell therapy.

Gremlin 1 Identifies a Skeletal Stem Cell with Bone, Cartilage, and Reticular Stromal Potential

PubMed Central

Worthley, Daniel L.; Churchill, Michael; Compton, Jocelyn T.; Tailor, Yagnesh; Rao, Meenakshi; Si, Yiling; Levin, Daniel; Schwartz, Matthew G.; Uygur, Aysu; Hayakawa, Yoku; Gross, Stefanie; Renz, Bernhard W.; Setlik, Wanda; Martinez, Ashley N.; Chen, Xiaowei; Nizami, Saqib; Lee, Heon Goo; Kang, H. Paco; Caldwell, Jon-Michael; Asfaha, Samuel; Westphalen, C. Benedikt; Graham, Trevor; Jin, Guangchun; Nagar, Karan; Wang, Hongshan; Kheirbek, Mazen A.; Kolhe, Alka; Carpenter, Jared; Glaire, Mark; Nair, Abhinav; Renders, Simon; Manieri, Nicholas; Muthupalani, Sureshkumar; Fox, James G.; Reichert, Maximilian; Giraud, Andrew S.; Schwabe, Robert F.; Pradere, Jean-Phillipe; Walton, Katherine; Prakash, Ajay; Gumucio, Deborah; Rustgi, Anil K.; Stappenbeck, Thaddeus S.; Friedman, Richard A.; Gershon, Michael D.; Sims, Peter; Grikscheit, Tracy; Lee, Francis Y.; Karsenty, Gerard; Mukherjee, Siddhartha; Wang, Timothy C.

2014-01-01

The stem cells that maintain and repair the postnatal skeleton remain undefined. One model suggests that perisinusoidal mesenchymal stem cells (MSCs) give rise to osteoblasts, chondrocytes, marrow stromal cells, and adipocytes, although the existence of these cells has not been proven through fate-mapping experiments. We demonstrate here that expression of the bone morphogenetic protein (BMP) antagonist gremlin 1 defines a population of osteochondroreticular (OCR) stem cells in the bone marrow. OCR stem cells self-renew and generate osteoblasts, chondrocytes, and reticular marrow stromal cells, but not adipocytes. OCR stem cells are concentrated within the metaphysis of long bones not in the perisinusoidal space and are needed for bone development, bone remodeling, and fracture repair. Grem1 expression also identifies intestinal reticular stem cells (iRSCs) that are cells of origin for the periepithelial intestinal mesenchymal sheath. Grem1 expression identifies distinct connective tissue stem cells in both the bone (OCR stem cells) and the intestine (iRSCs). PMID:25594183

Biochemistry of epidermal stem cells.

PubMed

Eckert, Richard L; Adhikary, Gautam; Balasubramanian, Sivaprakasam; Rorke, Ellen A; Vemuri, Mohan C; Boucher, Shayne E; Bickenbach, Jackie R; Kerr, Candace

2013-02-01

The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue. A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer. An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis. Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Basics and applications of stem cells in the pancreas.

PubMed

Sekine, Keisuke; Taniguchi, Hideki

2012-11-01

Enormous efforts have been made to establish pancreatic stem/progenitor cells as a source for regenerative medicine for the treatment of diabetes mellitus. In recent years, it has been recognized that the self-renewal of beta cells is the dominant process involved in postnatal beta-cell regeneration and expansion. Nevertheless, several in-vitro studies have suggested that ductal or as yet unidentified cells are candidates for pancreatic stem/progenitor cells that can differentiate into multilineage cells, including insulin(+) cells. The question remains as to whether beta cells are generated postnatally from stem/progenitor cells other than pre-existing beta cells. Furthermore, mutated pancreatic stem cells are considered to be prospective candidates for cancer stem cells or tumor-initiating cells. This review highlights recent progress in pancreatic stem/progenitor cell research.

Ablation of proliferating neural stem cells during early life is sufficient to reduce adult hippocampal neurogenesis.

PubMed

Youssef, Mary; Krish, Varsha S; Kirshenbaum, Greer S; Atsak, Piray; Lass, Tamara J; Lieberman, Sophie R; Leonardo, E David; Dranovsky, Alex

2018-05-09

Environmental exposures during early life, but not during adolescence or adulthood, lead to persistent reductions in neurogenesis in the adult hippocampal dentate gyrus (DG). The mechanisms by which early life exposures lead to long-term deficits in neurogenesis remain unclear. Here, we investigated whether targeted ablation of dividing neural stem cells during early life is sufficient to produce long-term decreases in DG neurogenesis. Having previously found that the stem cell lineage is resistant to long-term effects of transient ablation of dividing stem cells during adolescence or adulthood (Kirshenbaum et al., 2014), we used a similar pharmacogenetic approach to target dividing neural stem cells for elimination during early life periods sensitive to environmental insults. We then assessed the Nestin stem cell lineage in adulthood. We found that the adult neural stem cell reservoir was depleted following ablation during the first postnatal week, when stem cells were highly proliferative, but not during the third postnatal week, when stem cells were more quiescent. Remarkably, ablating proliferating stem cells during either the first or third postnatal week led to reduced adult neurogenesis out of proportion to the changes in the stem cell pool, indicating a disruption of the stem cell function or niche following stem cell ablation in early life. These results highlight the first three postnatal weeks as a series of sensitive periods during which elimination of dividing stem cells leads to lasting alterations in adult DG neurogenesis and stem cell function. These findings contribute to our understanding of the relationship between DG development and adult neurogenesis, as well as suggest a possible mechanism by which early life experiences may lead to lasting deficits in adult hippocampal neurogenesis. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

State performance in pluripotent and adult stem cell research, 2009-2016.

PubMed

Surani, Sana H; Levine, Aaron D

2018-04-01

To examine how the geographic distribution of pluripotent and adult stem cell research publications within the USA differs from other areas of biomedical research. Publication count data for pluripotent stem cell research, adult stem cell research and a comparison group representative of biomedical research more broadly were collected and analyzed for each US state from 2009 to 2016. The distribution of pluripotent stem cell research differed from the other fields with overperformance in pluripotent stem cell research observed in California, as well as Wisconsin, Massachusetts, Maryland and Connecticut. Our analysis suggests that permissive state stem cell policy may be one of the several factors contributing to strong state performance in pluripotent stem cell research.

Stem cell clinics online: the direct-to-consumer portrayal of stem cell medicine.

PubMed

Lau, Darren; Ogbogu, Ubaka; Taylor, Benjamin; Stafinski, Tania; Menon, Devidas; Caulfield, Timothy

2008-12-04

Despite the immature state of stem cell medicine, patients are seeking and accessing putative stem cell therapies in an "early market" in which direct-to-consumer advertising via the internet likely plays an important role. We analyzed stem cell clinic websites and appraised the relevant published clinical evidence of stem cell therapies to address three questions about the direct-to-consumer portrayal of stem cell medicine in this early market: What sorts of therapies are being offered? How are they portrayed? Is there clinical evidence to support the use of these therapies? We found that the portrayal of stem cell medicine on provider websites is optimistic and unsubstantiated by peer-reviewed literature.

Effects of Telomerase and Telomere Length on Epidermal Stem Cell Behavior

NASA Astrophysics Data System (ADS)

Flores, Ignacio; Cayuela, María L.; Blasco, María A.

2005-08-01

A key process in organ homeostasis is the mobilization of stem cells out of their niches. We show through analysis of mouse models that telomere length, as well as the catalytic component of telomerase, Tert, are critical determinants in the mobilization of epidermal stem cells. Telomere shortening inhibited mobilization of stem cells out of their niche, impaired hair growth, and resulted in suppression of stem cell proliferative capacity in vitro. In contrast, Tert overexpression in the absence of changes in telomere length promoted stem cell mobilization, hair growth, and stem cell proliferation in vitro. The effects of telomeres and telomerase on stem cell biology anticipate their role in cancer and aging.

Prospects for neural stem cell-based therapies for neurological diseases.

PubMed

Imitola, Jaime

2007-10-01

Neural stem and progenitor cells have great potential for the treatment of neurological disorders. However, many obstacles remain to translate this field to the patient's bedside, including rationales for using neural stem cells in individual neurological disorders; the challenges of neural stem cell biology; and the caveats of current strategies of isolation and culturing neural precursors. Addressing these challenges is critical for the translation of neural stem cell biology to the clinic. Recent work using neural stem cells has yielded novel biologic concepts such as the importance of the reciprocal interaction between neural stem cells and the neurodegenerative environment. The prospect of using transplants of neural stem cells and progenitors to treat neurological diseases requires a better understanding of the molecular mechanisms of both neural stem cell behavior in experimental models and the intrinsic repair capacity of the injured brain.

Impact of genomic damage and ageing on stem cell function

PubMed Central

Behrens, Axel; van Deursen, Jan M.; Rudolph, K. Lenhard; Schumacher, Björn

2014-01-01

Impairment of stem cell function contributes to the progressive deterioration of tissue maintenance and repair with ageing. Evidence is mounting that age-dependent accumulation of DNA damage in both stem cells and cells that comprise the stem cell microenvironment are partly responsible for stem cell dysfunction with ageing. Here, we review the impact of the various types of DNA damage that accumulate with ageing on stem cell functionality, as well as the development of cancer. We discuss DNA-damage-induced cell intrinsic and extrinsic alterations that influence these processes, and review recent advances in understanding systemic adjustments to DNA damage and how they affect stem cells. PMID:24576896

Lgr proteins in epithelial stem cell biology.

PubMed

Barker, Nick; Tan, Shawna; Clevers, Hans

2013-06-01

The ultimate success of global efforts to exploit adult stem cells for regenerative medicine will depend heavily on the availability of robust, highly selective stem cell surface markers that facilitate the isolation of stem cells from human tissues. Any subsequent expansion or manipulation of isolated stem cells will also require an intimate knowledge of the mechanisms that regulate these cells, to ensure maintenance of their regenerative capacities and to minimize the risk of introducing undesirable growth traits that could pose health risks for patients. A subclass of leucine-rich repeat-containing G-protein-coupled receptor (Lgr) proteins has recently gained prominence as adult stem cell markers with crucial roles in maintaining stem cell functions. Here, we discuss the major impact that their discovery has had on our understanding of adult stem cell biology in various self-renewing tissues and in accelerating progress towards the development of effective stem cell therapies.

Characterization of Amniotic Stem Cells

PubMed Central

Koike, Chika; Zhou, Kaixuan; Takeda, Yuji; Fathy, Moustafa; Okabe, Motonori; Yoshida, Toshiko; Nakamura, Yukio; Kato, Yukio

2014-01-01

Abstract The amnion membrane is developed from embryo-derived cells, and amniotic cells have been shown to exhibit multidifferentiation potential. These cells represent a desirable source for stem cells for a variety of reasons. However, to date very few molecular analyses of amnion-derived cells have been reported, and efficient markers for isolating the stem cells remain unclear. This paper assesses the characterization of amnion-derived cells as stem cells by examining stemness marker expressions for amnion-derived epithelial cells and mesenchymal cells by flow cytometry, immunocytochemistry, and quantitative PCR. Flow cytometry revealed that amnion epithelial cells expressed CD133, CD 271, and TRA-1-60, whereas mecenchymal cells expressed CD44, CD73, CD90, and CD105. Immunohistochemistry showed that both cells expressed the stemness markers Oct3/4, Sox2, Klf4, and SSEA4. Stemness genes' expression in amnion epithelial cells, mesenchymal cells, fibroblast, bone marrow–derived mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) was compared by quantitative reverse-transcription polymerase chain reaction (RT-PCR). Amnion-derived epithelial cells and mesenchymal cells expressed Oct3/4, Nanog, and Klf4 more than bone marrow–derived MSCs. The sorted TRA1-60–positive cells expressed Oct3/4, Nanog, and Klf4 more than unsorted cells or TRA1-60–negative cells. TRA1-60 can be a marker for isolating amnion epithelial stem cells. PMID:25068631

Electroporation of the Testis

NASA Astrophysics Data System (ADS)

Yomogida, Kentaro

The mature mammalian testis is a marvelous organ that produces numerous sperm cells during its reproductive phase. This biologically significant process consists of three steps: stem cell self-renewal and differentiation, meiosis and genetic recombination, and haploid cell morphogenesis into sperm (Russell et al., 1990). The first step provides a good model for investigating the molecular mechanism of stem cell regulation. Currently, the mechanism underlying sperm cell production is a very exciting topic in regenerative medicine (Lensch et al. 2007; Okita et al., 2007). The spermatogonial stem cell system has several advantages, including the easy histological identification of stem cells (Russell et al., 1990), a clear relationship between stem cells and the supporting Sertoli cells, which provide a stem cell niche (Tadokoro et al., 2002; Yomogida et al., 2003), and a transplantation assay for stem cell activity (Oatley & Brinster, 2006). Although germline stem (GS) cells derived from the gonocytes in newborn testis constitute a suitable in vitro system for investigating the properties of spermatogonial stem cells (Kanatsu-Shinohara et al., 2003, 2004), studies using living mammalian testes continue to provide information regarding the roles of the stem cell niche. In vivo electroporation of the supporting cells in the testis will expand our ability to study it.

Current applications of human pluripotent stem cells: possibilities and challenges.

PubMed

Ho, Pai-Jiun; Yen, Men-Luh; Yet, Shaw-Fang; Yen, B Linju

2012-01-01

Stem cells are self-renewable cells with the differentiation capacity to develop into somatic cells with biological functions. This ability to sustain a renewable source of multi- and/or pluripotential differentiation has brought new hope to the field of regenerative medicine in terms of cell therapy and tissue engineering. Moreover, stem cells are invaluable tools as in vitro models for studying diverse fields, from basic scientific questions such as developmental processes and lineage commitment, to practical application including drug screening and testing. The stem cells with widest differentiation potential are pluripotent stem cells (PSCs), which are rare cells with the ability to generate somatic cells from all three germ layers. PSCs are considered the most optimal choice for therapeutic potential of stem cells, bringing new impetus to the field of regenerative medicine. In this article, we discuss the therapeutic potential of human PSCs (hPSCs) including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), reviewing the current preclinical and clinical data using these stem cells. We describe the classification of different sources of hPSCs, ongoing research, and currently encountered clinical obstacles of these novel and versatile human stem cells.

Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction.

PubMed

Miyahara, Yoshinori; Nagaya, Noritoshi; Kataoka, Masaharu; Yanagawa, Bobby; Tanaka, Koichi; Hao, Hiroyuki; Ishino, Kozo; Ishida, Hideyuki; Shimizu, Tatsuya; Kangawa, Kenji; Sano, Shunji; Okano, Teruo; Kitamura, Soichiro; Mori, Hidezo

2006-04-01

Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue-derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.

Multiple Roles of Soluble Sugars in the Establishment of Gunnera-Nostoc Endosymbiosis1[OA

PubMed Central

Khamar, Hima J.; Breathwaite, Erick K.; Prasse, Christine E.; Fraley, Elizabeth R.; Secor, Craig R.; Chibane, Fairouz L.; Elhai, Jeff; Chiu, Wan-Ling

2010-01-01

Gunnera plants have the unique ability to form endosymbioses with N2-fixing cyanobacteria, primarily Nostoc. Cyanobacteria enter Gunnera through transiently active mucilage-secreting glands on stems. We took advantage of the nitrogen (N)-limitation-induced gland development in Gunnera manicata to identify factors that may enable plant tissue to attract and maintain cyanobacteria colonies. Cortical cells in stems of N-stressed Gunnera plants were found to accumulate a copious amount of starch, while starch in the neighboring mature glands was nearly undetectable. Instead, mature glands accumulated millimolar concentrations of glucose (Glc) and fructose (Fru). Successful colonization by Nostoc drastically reduced sugar accumulation in the surrounding tissue. Consistent with the abundance of Glc and Fru in the gland prior to Nostoc colonization, genes encoding key enzymes for sucrose and starch hydrolysis (e.g. cell wall invertase, α-amylase, and starch phosphorylase) were expressed at higher levels in stem segments with glands than those without. In contrast, soluble sugars were barely detectable in mucilage freshly secreted from glands. Different sugars affected Nostoc’s ability to differentiate motile hormogonia in a manner consistent with their locations. Galactose and arabinose, the predominant constituents of polysaccharides in the mucilage, had little or no inhibitory effect on hormogonia differentiation. On the other hand, soluble sugars that accumulated in gland tissue, namely sucrose, Glc, and Fru, inhibited hormogonia differentiation and enhanced vegetative growth. Results from this study suggest that, in an N-limited environment, mature Gunnera stem glands may employ different soluble sugars to attract Nostoc and, once the cyanobacteria are internalized, to maintain them in the N2-fixing vegetative state. PMID:20833727

Genetic and epigenetic instability of stem cells.

PubMed

Rajamani, Karthyayani; Li, Yuan-Sheng; Hsieh, Dean-Kuo; Lin, Shinn-Zong; Harn, Horng-Jyh; Chiou, Tzyy-Wen

2014-01-01

Recently, research on stem cells has been receiving an increasing amount of attention, both for its advantages and disadvantages. Genetic and epigenetic instabilities among stem cells have been a recurring obstacle to progress in regenerative medicine using stem cells. Various reports have stated that these instabilities can transform stem cells when transferred in vivo and thus have the potential to develop tumors. Previous research has shown that various extrinsic and intrinsic factors can contribute to the stability of stem cells. The extrinsic factors include growth supplements, growth factors, oxygen tension, passage technique, and cryopreservation. Controlling these factors based on previous reports may assist researchers in developing strategies for the production and clinical application of "safe" stem cells. On the other hand, the intrinsic factors can be unpredictable and uncontrollable; therefore, to ensure the successful use of stem cells in regenerative medicine, it is imperative to develop and implement appropriate strategies and technique for culturing stem cells and to confirm the genetic and epigenetic safety of these stem cells before employing them in clinical trials.

Dipeptide species regulate p38MAPK–Smad3 signalling to maintain chronic myelogenous leukaemia stem cells

PubMed Central

Naka, Kazuhito; Jomen, Yoshie; Ishihara, Kaori; Kim, Junil; Ishimoto, Takahiro; Bae, Eun-Jin; Mohney, Robert P.; Stirdivant, Steven M.; Oshima, Hiroko; Oshima, Masanobu; Kim, Dong-Wook; Nakauchi, Hiromitsu; Takihara, Yoshihiro; Kato, Yukio; Ooshima, Akira; Kim, Seong-Jin

2015-01-01

Understanding the specific survival of the rare chronic myelogenous leukaemia (CML) stem cell population could provide a target for therapeutics aimed at eradicating these cells. However, little is known about how survival signalling is regulated in CML stem cells. In this study, we survey global metabolic differences between murine normal haematopoietic stem cells (HSCs) and CML stem cells using metabolomics techniques. Strikingly, we show that CML stem cells accumulate significantly higher levels of certain dipeptide species than normal HSCs. Once internalized, these dipeptide species activate amino-acid signalling via a pathway involving p38MAPK and the stemness transcription factor Smad3, which promotes CML stem cell maintenance. Importantly, pharmacological inhibition of dipeptide uptake inhibits CML stem cell activity in vivo. Our results demonstrate that dipeptide species support CML stem cell maintenance by activating p38MAPK–Smad3 signalling in vivo, and thus point towards a potential therapeutic target for CML treatment. PMID:26289811

Engineering Stem Cells for Biomedical Applications.

PubMed

Yin, Perry T; Han, Edward; Lee, Ki-Bum

2016-01-07

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling TSC and LAM Using Patient Derived Induced Pluripotent Stem Cells

DTIC Science & Technology

2016-10-01

lentiviral knockdown, and CRISPR /Cas9 genome editing in embryonic stem cells (ESCs). We have characterized the iPSCs extensively and found that they display...induced pluripotent stem cells (iPSCs) embryonic stem cells (ESCs) reprogramming CRISPR /Cas9 genome editing neural stem cells (NSCs) neural crest... CRISPR /cas9 in two additional human pluripotent stem cell lines (WA07 (H7) – female cell line registry #0061; and a control male iPSC lines generated

Biochemistry of epidermal stem cells☆

PubMed Central

Eckert, Richard L.; Adhikary, Gautam; Balasubramanian, Sivaprakasam; Rorke, Ellen A.; Vemuri, Mohan C.; Boucher, Shayne E.; Bickenbach, Jackie R.; Kerr, Candace

2014-01-01

Background The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue. Scope of review A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer. Major conclusions An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis. General significance Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells. PMID:22820019

YAP/TAZ enhance mammalian embryonic neural stem cell characteristics in a Tead-dependent manner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Dasol; Byun, Sung-Hyun; Park, Soojeong

Mammalian brain development is regulated by multiple signaling pathways controlling cell proliferation, migration and differentiation. Here we show that YAP/TAZ enhance embryonic neural stem cell characteristics in a cell autonomous fashion using diverse experimental approaches. Introduction of retroviral vectors expressing YAP or TAZ into the mouse embryonic brain induced cell localization in the ventricular zone (VZ), which is the embryonic neural stem cell niche. This change in cell distribution in the cortical layer is due to the increased stemness of infected cells; YAP-expressing cells were colabeled with Sox2, a neural stem cell marker, and YAP/TAZ increased the frequency and sizemore » of neurospheres, indicating enhanced self-renewal- and proliferative ability of neural stem cells. These effects appear to be TEA domain family transcription factor (Tead)–dependent; a Tead binding-defective YAP mutant lost the ability to promote neural stem cell characteristics. Consistently, in utero gene transfer of a constitutively active form of Tead2 (Tead2-VP16) recapitulated all the features of YAP/TAZ overexpression, and dominant negative Tead2-EnR resulted in marked cell exit from the VZ toward outer cortical layers. Taken together, these results indicate that the Tead-dependent YAP/TAZ signaling pathway plays important roles in neural stem cell maintenance by enhancing stemness of neural stem cells during mammalian brain development. - Highlights: • Roles of YAP and Tead in vivo during mammalian brain development are clarified. • Expression of YAP promotes embryonic neural stem cell characteristics in vivo in a cell autonomous fashion. • Enhancement of neural stem cell characteristics by YAP depends on Tead. • Transcriptionally active form of Tead alone can recapitulate the effects of YAP. • Transcriptionally repressive form of Tead severely reduces stem cell characteristics.« less

Recent progress in stem cell differentiation directed by material and mechanical cues.

PubMed

Lin, Xunxun; Shi, Yuan; Cao, Yilin; Liu, Wei

2016-02-02

Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular field.

Engineering Hydrogel Microenvironments to Recapitulate the Stem Cell Niche.

PubMed

Madl, Christopher M; Heilshorn, Sarah C

2018-06-04

Stem cells are a powerful resource for many applications including regenerative medicine, patient-specific disease modeling, and toxicology screening. However, eliciting the desired behavior from stem cells, such as expansion in a naïve state or differentiation into a particular mature lineage, remains challenging. Drawing inspiration from the native stem cell niche, hydrogel platforms have been developed to regulate stem cell fate by controlling microenvironmental parameters including matrix mechanics, degradability, cell-adhesive ligand presentation, local microstructure, and cell-cell interactions. We survey techniques for modulating hydrogel properties and review the effects of microenvironmental parameters on maintaining stemness and controlling differentiation for a variety of stem cell types. Looking forward, we envision future hydrogel designs spanning a spectrum of complexity, ranging from simple, fully defined materials for industrial expansion of stem cells to complex, biomimetic systems for organotypic cell culture models.

Incorporation of Biomaterials in Multicellular Aggregates Modulates Pluripotent Stem Cell Differentiation

PubMed Central

Bratt-Leal, Andrés M.; Carpenedo, Richard L.; Ungrin, Mark; Zandstra, Peter W.; McDevitt, Todd C.

2010-01-01

Biomaterials are increasingly being used to engineer the biochemical and biophysical properties of the extracellular stem cell microenvironment in order to tailor niche characteristics and direct cell phenotype. To date, stem cell-biomaterial interactions have largely been studied by introducing stem cells into artificial environments, such as 2D cell culture on biomaterial surfaces, encapsulation of cell suspensions within hydrogel materials, or cell seeding on 3D polymeric scaffolds. In this study, microparticles fabricated from different materials, such as agarose, PLGA and gelatin, were stably integrated, in a dose-dependent manner, within aggregates of pluripotent stem cells (PSCs) prior to differentiation as a means to directly examine stem cell-biomaterial interactions in 3D. Interestingly, the presence of the materials within the stem cell aggregates differentially modulated the gene and protein expression patterns of several differentiation markers without adversely affecting cell viability. Microparticle incorporation within 3D stem cell aggregates can control the spatial presentation of extracellular environmental cues (i.e. soluble factors, extracellular matrix and intercellular adhesion molecules) as a means to direct the differentiation of stem cells for tissue engineering and regenerative medicine applications. In addition, these results suggest that the physical presence of microparticles within stem cell aggregates does not compromise PSC differentiation, but in fact the choice of biomaterials can impact the propensity of stem cells to adopt particular differentiated cell phenotypes. PMID:20864164

Markers for the identification of tendon-derived stem cells in vitro and tendon stem cells in situ - update and future development.

PubMed

Lui, Pauline Po Yee

2015-06-02

The efficacy of tendon-derived stem cells (TDSCs) for the promotion of tendon and tendon-bone junction repair has been reported in animal studies. Modulation of the tendon stem cell niche in vivo has also been reported to influence tendon structure. There is a need to have specific and reliable markers that can define TDSCs in vitro and tendon stem cells in situ for several reasons: to understand the basic biology of TDSCs and their subpopulations in vitro; to understand the identity, niches and functions of tendon/progenitor stem cells in vivo; to meet the governmental regulatory requirements for quality of TDSCs when translating the exciting preclinical findings into clinical trial/practice; and to develop new treatment strategies for mobilizing endogenous stem/progenitor cells in tendon. TDSCs were reported to express the common mesenchymal stem cell (MSC) markers and some embryonic stem cell (ESC) markers, and there were attempts to use these markers to label tendon stem cells in situ. Are these stem cell markers useful for the identification of TDSCs in vitro and tracking of tendon stem cells in situ? This review aims to discuss the values of the panel of MSC, ESC and tendon-related markers for the identification of TDSCs in vitro. Important factors influencing marker expression by TDSCs are discussed. The usefulness and limitations of the panel of MSC, ESC and tendon-related markers for tracking stem cells in tendon, especially tendon stem cells, in situ are then reviewed. Future research directions are proposed.

Haematopoietic stem and progenitor cells from human pluripotent stem cells

PubMed Central

Sugimura, Ryohichi; Jha, Deepak Kumar; Han, Areum; Soria-Valles, Clara; da Rocha, Edroaldo Lummertz; Lu, Yi-Fen; Goettel, Jeremy A.; Serrao, Erik; Rowe, R. Grant; Malleshaiah, Mohan; Wong, Irene; Sousa, Patricia; Zhu, Ted N.; Ditadi, Andrea; Keller, Gordon; Engelman, Alan N.; Snapper, Scott B.; Doulatov, Sergei; Daley, George Q.

2018-01-01

A variety of tissue lineages can be differentiated from pluripotent stem cells by mimicking embryonic development through stepwise exposure to morphogens, or by conversion of one differentiated cell type into another by enforced expression of master transcription factors. Here, to yield functional human haematopoietic stem cells, we perform morphogen-directed differentiation of human pluripotent stem cells into haemogenic endothelium followed by screening of 26 candidate haematopoietic stem-cell-specifying transcription factors for their capacity to promote multi-lineage haematopoietic engraftment in mouse hosts. We recover seven transcription factors (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1 and SPI1) that are sufficient to convert haemogenic endothelium into haematopoietic stem and progenitor cells that engraft myeloid, B and T cells in primary and secondary mouse recipients. Our combined approach of morphogen-driven differentiation and transcription-factor-mediated cell fate conversion produces haematopoietic stem and progenitor cells from pluripotent stem cells and holds promise for modelling haematopoietic disease in humanized mice and for therapeutic strategies in genetic blood disorders. PMID:28514439

Stem Cells in the Trabecular Meshwork for Regulating Intraocular Pressure.

PubMed

Yun, Hongmin; Zhou, Yi; Wills, Andrew; Du, Yiqin

2016-06-01

Intraocular pressure (IOP) is still the main treatment target for glaucoma. Outflow resistance mainly exists at the trabecular meshwork (TM) outflow pathway, which is responsible for IOP regulation. Changes of TM cellularity and TM extracellular matrix turnover may play important roles in IOP regulation. In this article, we review basic anatomy and physiology of the outflow pathway and TM stem cell characteristics regarding the location, isolation, identification and function. TM stem cells are localized at the insert region of the TM and are label-retaining in vivo. They can be isolated by side-population cell sorting, cloning culture, or sphere culture. TM stem cells are multipotent with the ability to home to the TM region and differentiate into TM cells in vivo. Other stem cell types, such as adipose-derived stem cells, mesenchymal stem cells and induced pluripotent stem cells have been discovered for TM cell differentiation and TM regeneration. We also review glaucomatous animal models, which are suitable to study stem cell-based therapies for TM regeneration.

Stem Cells in the Trabecular Meshwork for Regulating Intraocular Pressure

PubMed Central

Yun, Hongmin; Zhou, Yi; Wills, Andrew

2016-01-01

Abstract Intraocular pressure (IOP) is still the main treatment target for glaucoma. Outflow resistance mainly exists at the trabecular meshwork (TM) outflow pathway, which is responsible for IOP regulation. Changes of TM cellularity and TM extracellular matrix turnover may play important roles in IOP regulation. In this article, we review basic anatomy and physiology of the outflow pathway and TM stem cell characteristics regarding the location, isolation, identification and function. TM stem cells are localized at the insert region of the TM and are label-retaining in vivo. They can be isolated by side-population cell sorting, cloning culture, or sphere culture. TM stem cells are multipotent with the ability to home to the TM region and differentiate into TM cells in vivo. Other stem cell types, such as adipose-derived stem cells, mesenchymal stem cells and induced pluripotent stem cells have been discovered for TM cell differentiation and TM regeneration. We also review glaucomatous animal models, which are suitable to study stem cell-based therapies for TM regeneration. PMID:27183473

New perspectives in human stem cell therapeutic research.

PubMed

Trounson, Alan

2009-06-11

Human stem cells are in evaluation in clinical stem cell trials, primarily as autologous bone marrow studies, autologous and allogenic mesenchymal stem cell trials, and some allogenic neural stem cell transplantation projects. Safety and efficacy are being addressed for a number of disease state applications. There is considerable data supporting safety of bone marrow and mesenchymal stem cell transplants but the efficacy data are variable and of mixed benefit. Mechanisms of action of many of these cells are unknown and this raises the concern of unpredictable results in the future. Nevertheless there is considerable optimism that immune suppression and anti-inflammatory properties of mesenchymal stem cells will be of benefit for many conditions such as graft versus host disease, solid organ transplants and pulmonary fibrosis. Where bone marrow and mesenchymal stem cells are being studied for heart disease, stroke and other neurodegenerative disorders, again progress is mixed and mostly without significant benefit. However, correction of multiple sclerosis, at least in the short term is encouraging. Clinical trials on the use of embryonic stem cell derivatives for spinal injury and macular degeneration are beginning and a raft of other clinical trials can be expected soon, for example, the use of neural stem cells for killing inoperable glioma and embryonic stem cells for regenerating beta islet cells for diabetes. The change in attitude to embryonic stem cell research with the incoming Obama administration heralds a new co-operative environment for study and evaluation of stem cell therapies. The Californian stem cell initiative (California Institute for Regenerative Medicine) has engendered global collaboration for this new medicine that will now also be supported by the US Federal Government. The active participation of governments, academia, biotechnology, pharmaceutical companies, and private investment is a powerful consortium for advances in health.

Invincible, but not invisible: imaging approaches toward in vivo detection of cancer stem cells.

PubMed

Hart, Lori S; El-Deiry, Wafik S

2008-06-10

With evidence emerging in support of a cancer stem-cell model of carcinogenesis, it is of paramount importance to identify and image these elusive cells in their natural environment. The cancer stem-cell hypothesis has the potential to explain unresolved questions of tumorigenesis, tumor heterogeneity, chemotherapeutic and radiation resistance, and even the metastatic phenotype. Intravital imaging of cancer stem cells could be of great value for determining prognosis, as well as monitoring therapeutic efficacy and influencing therapeutic protocols. Cancer stem cells represent a rare population of cells, as low as 0.1% of cells within a human tumor, and the phenotype of isolated cancer stem cells is easily altered when placed under in vitro conditions. This represents a challenge in studying cancer stem cells without manipulation or extraction from their natural environment. Advanced imaging techniques allow for the in vivo observation of physiological events at cellular resolution. Cancer stem-cell studies must take advantage of such technology to promote a better understanding of the cancer stem-cell model in relation to tumor growth and metastasis, as well as to potentially improve on the principles by which cancers are treated. This review examines the opportunities for in vivo imaging of putative cancer stem cells with regard to currently accepted cancer stem-cell characteristics and advanced imaging technologies.

Neural stem cell-based treatment for neurodegenerative diseases.

PubMed

Kim, Seung U; Lee, Hong J; Kim, Yun B

2013-10-01

Human neurodegenerative diseases such as Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD) are caused by a loss of neurons and glia in the brain or spinal cord. Neurons and glial cells have successfully been generated from stem cells such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs) and neural stem cells (NSCs), and stem cell-based cell therapies for neurodegenerative diseases have been developed. A recent advance in generation of a new class of pluripotent stem cells, induced pluripotent stem cells (iPSCs), derived from patients' own skin fibroblasts, opens doors for a totally new field of personalized medicine. Transplantation of NSCs, neurons or glia generated from stem cells in animal models of neurodegenerative diseases, including PD, HD, ALS and AD, demonstrates clinical improvement and also life extension of these animals. Additional therapeutic benefits in these animals can be provided by stem cell-mediated gene transfer of therapeutic genes such as neurotrophic factors and enzymes. Although further research is still needed, cell and gene therapy based on stem cells, particularly using neurons and glia derived from iPSCs, ESCs or NSCs, will become a routine treatment for patients suffering from neurodegenerative diseases and also stroke and spinal cord injury. © 2013 Japanese Society of Neuropathology.

Constitutive Proteasomal Degradation of TWIST-1 in Epithelial Ovarian Cancer Stem Cells Impacts Differentiation and Metastatic Potential

PubMed Central

Yin, Gang; Alvero, Ayesha B.; Craveiro, Vinicius; Holmberg, Jennie C.; Fu, Han-Hsuan; Montagna, Michele K.; Yang, Yang; Chefetz-Menaker, Ilana; Nuti, Sudhakar; Rossi, Michael; Silasi, Dan-Arin; Rutherford, Thomas; Mor, Gil

2013-01-01

Epithelial-mesenchymal transition (EMT) is a critical process for embryogenesis but is abnormally activated during cancer metastasis and recurrence. This process enables epithelial cancer cells to acquire mobility and traits associated with stemness. It is unknown whether epithelial stem cells or epithelial cancer stem cells are able to undergo EMT, and what molecular mechanism regulates this process in these specific cell types. We found that Epithelial Ovarian Cancer Stem cells (EOC stem cells) are the source of metastatic progenitor cells through a differentiation process involving EMT and Mesenchymal-Epithelial Transition (MET). We demonstrate both in vivo and in vitro the differentiation of EOC stem cells into mesenchymal spheroid-forming cells (MSFCs) and their capacity to initiate an active carcinomatosis. Furthermore, we demonstrate that human EOC stem cells injected i.p in mice are able to form ovarian tumors, suggesting that the EOC stem cells have the ability to “home” to the ovaries and establish tumors. Most interestingly, we found that TWIST1 is constitutively degraded in EOC stem cells, and that the acquisition of TWIST1 requires additional signals that will trigger the differentiation process. These findings are relevant for understanding the differentiation and metastasis process in EOC stem cells. PMID:22349827

Hepatic differentiation of pluripotent stem cells.

PubMed

Loya, Komal; Eggenschwiler, Reto; Ko, Kinarm; Sgodda, Malte; André, Francoise; Bleidissel, Martina; Schöler, Hans R; Cantz, Tobias

2009-10-01

In regenerative medicine pluripotent stem cells are considered to be a valuable self-renewing source for therapeutic cell transplantations, given that a functional organ-specific phenotype can be acquired by in vitro differentiation protocols. Furthermore, derivatives of pluripotent stem cells that mimic fetal progenitor stages could serve as an important tool to analyze organ development with in vitro approaches. Because of ethical issues regarding the generation of human embryonic stem (ES) cells, other sources for pluripotent stem cells are intensively studied. Like in less developed vertebrates, pluripotent stem cells can be generated from the female germline even in mammals, via parthenogenetic activation of oocytes. Recently, testis-derived pluripotent stem cells were derived from the male germline. Therefore, we compared two different hepatic differentiation approaches and analyzed the generation of definitive endoderm progenitor cells and their further maturation into a hepatic phenotype using murine parthenogenetic ES cells, germline-derived pluripotent stem cells, and ES cells. Applying quantitative RT-PCR, both germline-derived pluripotent cell lines show similar differentiation capabilities as normal murine ES cells and can be considered an alternative source for pluripotent stem cells in regenerative medicine.

An overview on ethical considerations in stem cell research in Iran and ethical recommendations: A review.

PubMed

Farajkhoda, Tahmineh

2017-02-01

Conducting research on the stem cell lines might bring some worthy good to public. Human Stem Cells (hSCs) research has provided opportunities for scientific progresses and new therapies, but some complex ethical matters should be noticed to ensure that stem cell research is carried out in an ethically appropriate manner. The aim of this review article is to discuss the importance of stem cell research, code of ethics for stem cell research in Iran and ethical recommendation. Generation of stem cells for research from human embryo or adult stem cells, saving, maintenance and using of them are the main ethical, legal and jurisprudence concerns in Iran. Concerns regarding human reproduction or human cloning, breach of human dignity, genetic manipulation and probability of tumorogenisity are observed in adult/somatic stem cells. Destruction of embryo to generate stem cell is an important matter in Iran. In this regards, obtaining stem cell from donated frozen embryos through infertility treatment that would be discarded is an acceptable solution in Iran for generation of embryo for research. Ethical, legal, and jurisprudence strategies for using adult/somatic stem cells are determination of ownership of stem cells, trade prohibition of human body, supervision on bio banks and information of Oversight Committee on Stem Cell Research. Recommendations to handle ethical issues for conducting stem cell research are well-designed studies, compliance codes of ethics in biomedical research (specifically codes of ethics on stem cell research, codes of ethics on clinical trials studies and codes of ethics on animals studies), appropriate collaboration with ethics committees and respecting of rights of participants (including both of human and animal rights) in research. In addition, there is a necessity for extending global networks of bioethics for strengthening communications within organizations at both the regional and international level, strengthening legislation systems, designing and establishing convenient collaborative educational courses at different levels.

An overview on ethical considerations in stem cell research in Iran and ethical recommendations: A review

PubMed Central

Farajkhoda, Tahmineh

2017-01-01

Conducting research on the stem cell lines might bring some worthy good to public. Human Stem Cells (hSCs) research has provided opportunities for scientific progresses and new therapies, but some complex ethical matters should be noticed to ensure that stem cell research is carried out in an ethically appropriate manner. The aim of this review article is to discuss the importance of stem cell research, code of ethics for stem cell research in Iran and ethical recommendation. Generation of stem cells for research from human embryo or adult stem cells, saving, maintenance and using of them are the main ethical, legal and jurisprudence concerns in Iran. Concerns regarding human reproduction or human cloning, breach of human dignity, genetic manipulation and probability of tumorogenisity are observed in adult/somatic stem cells. Destruction of embryo to generate stem cell is an important matter in Iran. In this regards, obtaining stem cell from donated frozen embryos through infertility treatment that would be discarded is an acceptable solution in Iran for generation of embryo for research. Ethical, legal, and jurisprudence strategies for using adult/somatic stem cells are determination of ownership of stem cells, trade prohibition of human body, supervision on bio banks and information of Oversight Committee on Stem Cell Research. Recommendations to handle ethical issues for conducting stem cell research are well-designed studies, compliance codes of ethics in biomedical research (specifically codes of ethics on stem cell research, codes of ethics on clinical trials studies and codes of ethics on animals studies), appropriate collaboration with ethics committees and respecting of rights of participants (including both of human and animal rights) in research. In addition, there is a necessity for extending global networks of bioethics for strengthening communications within organizations at both the regional and international level, strengthening legislation systems, designing and establishing convenient collaborative educational courses at different levels. PMID:28462397

Effect of Dedifferentiation on Time to Mutation Acquisition in Stem Cell-Driven Cancers

PubMed Central

Jilkine, Alexandra; Gutenkunst, Ryan N.

2014-01-01

Accumulating evidence suggests that many tumors have a hierarchical organization, with the bulk of the tumor composed of relatively differentiated short-lived progenitor cells that are maintained by a small population of undifferentiated long-lived cancer stem cells. It is unclear, however, whether cancer stem cells originate from normal stem cells or from dedifferentiated progenitor cells. To address this, we mathematically modeled the effect of dedifferentiation on carcinogenesis. We considered a hybrid stochastic-deterministic model of mutation accumulation in both stem cells and progenitors, including dedifferentiation of progenitor cells to a stem cell-like state. We performed exact computer simulations of the emergence of tumor subpopulations with two mutations, and we derived semi-analytical estimates for the waiting time distribution to fixation. Our results suggest that dedifferentiation may play an important role in carcinogenesis, depending on how stem cell homeostasis is maintained. If the stem cell population size is held strictly constant (due to all divisions being asymmetric), we found that dedifferentiation acts like a positive selective force in the stem cell population and thus speeds carcinogenesis. If the stem cell population size is allowed to vary stochastically with density-dependent reproduction rates (allowing both symmetric and asymmetric divisions), we found that dedifferentiation beyond a critical threshold leads to exponential growth of the stem cell population. Thus, dedifferentiation may play a crucial role, the common modeling assumption of constant stem cell population size may not be adequate, and further progress in understanding carcinogenesis demands a more detailed mechanistic understanding of stem cell homeostasis. PMID:24603301

PGE2 /EP4 Signaling Controls the Transfer of the Mammary Stem Cell State by Lipid Rafts in Extracellular Vesicles.

PubMed

Lin, Meng-Chieh; Chen, Shih-Yin; Tsai, Ho-Min; He, Pei-Lin; Lin, Yen-Chun; Herschman, Harvey; Li, Hua-Jung

2017-02-01

Prostaglandin E 2 (PGE 2 )-initiated signaling contributes to stem cell homeostasis and regeneration. However, it is unclear how PGE 2 signaling controls cell stemness. This study identifies a previously unknown mechanism by which PGE 2 /prostaglandin E receptor 4 (EP 4 ) signaling regulates multiple signaling pathways (e.g., PI3K/Akt signaling, TGFβ signaling, Wnt signaling, EGFR signaling) which maintain the basal mammary stem cell phenotype. A shift of basal mammary epithelial stem cells (MaSCs) from a mesenchymal/stem cell state to a non-basal-MaSC state occurs in response to prostaglandin E receptor 4 (EP 4 ) antagonism. EP 4 antagonists elicit release of signaling components, by controlling their trafficking into extracellular vesicles/exosomes in a lipid raft/caveolae-dependent manner. Consequently, EP 4 antagonism indirectly inactivates, through induced extracellular vesicle/exosome release, pathways required for mammary epithelial stem cell homeostasis, e.g. canonical/noncanonical Wnt, TGFβ and PI3K/Akt pathways. EP 4 antagonism causes signaling receptors and signaling components to shift from non-lipid raft fractions to lipid raft fractions, and to then be released in EP 4 antagonist-induced extracellular vesicles/exosomes, resulting in the loss of the stem cell state by mammary epithelial stem cells. In contrast, luminal mammary epithelial cells can acquire basal stem cell properties following ingestion of EP 4 antagonist-induced stem cell extracellular vesicles/exosomes, and can then form mammary glands. These findings demonstrate that PGE 2 /EP 4 signaling controls homeostasis of mammary epithelial stem cells through regulating extracellular vesicle/exosome release. Reprogramming of mammary epithelial cells can result from EP 4 -mediated stem cell property transfer by extracellular vesicles/exosomes containing caveolae-associated proteins, between mammary basal and luminal epithelial cells. Stem Cells 2017;35:425-444. © 2016 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

The Drosophila ovarian and testis stem cell niches: similar somatic stem cells and signals.

PubMed

Decotto, Eva; Spradling, Allan C

2005-10-01

The stem cell niches at the apex of Drosophila ovaries and testes have been viewed as distinct in two major respects. While both contain germline stem cells, the testis niche also contains "cyst progenitor" stem cells, which divide to produce somatic cells that encase developing germ cells. Moreover, while both niches utilize BMP signaling, the testis niche requires a key JAK/STAT signal. We now show, by lineage marking, that the ovarian niche also contains a second type of stem cell. These "escort stem cells" morphologically resemble testis cyst progenitor cells and their daughters encase developing cysts before undergoing apoptosis at the time of follicle formation. In addition, we show that JAK/STAT signaling also plays a critical role in ovarian niche function, and acts within escort cells. These observations reveal striking similarities in the stem cell niches of male and female gonads, and suggest that they are largely governed by common mechanisms.

How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia

PubMed Central

Robert, Elisabeth M. R.; Jambia, Abudhabi H.; Schmitz, Nele; De Ryck, Dennis J. R.; De Mey, Johan; Kairo, James G.; Dahdouh-Guebas, Farid; Beeckman, Hans; Koedam, Nico

2014-01-01

Background and Aims Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) during 1 year. Key Results Patchiness was found in the radial growth and shrinkage and swelling patterns of Avicennia stems. It was, however, potentially rather than systematically present, i.e. stems reacted either concentrically or patchily to environment triggers, and it was fresh water availability and not tidal inundation that affected radial increment. Conclusions It is concluded that the ability to develop successive cambia in a patchy way enables Avicennia trees to adapt to changes in the prevailing environmental conditions, enhancing its survival in the highly dynamic mangrove environment. Limited water could be used in a more directive way, investing all the attainable resources in only some locations of the tree stem so that at least at these locations there is enough water to, for example, overcome vessel embolisms or create new cells. As these locations change with time, the overall functioning of the tree can be maintained. PMID:24510216

Placenta-an alternative source of stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matikainen, Tiina; Laine, Jarmo

2005-09-01

The two most promising practical applications of human stem cells are cellular replacement therapies in human disease and toxicological screening of candidate drug molecules. Both require a source of human stem cells that can be isolated, purified, expanded in number and differentiated into the cell type of choice in a controlled manner. Currently, uses of both embryonic and adult stem cells are investigated. While embryonic stem cells are pluripotent and can differentiate into any specialised cell type, their use requires establishment of embryonic stem cell lines using the inner cell mass of an early pre-implantation embryo. As the blastocyst ismore » destroyed during the process, ethical issues need to be carefully considered. The use of embryonic stem cells is also limited by the difficulties in growing large numbers of the cells without inducing spontaneous differentiation, and the problems in controlling directed differentiation of the cells. The use of adult stem cells, typically derived from bone marrow, but also from other tissues, is ethically non-controversial but their differentiation potential is more limited than that of the embryonic stem cells. Since human cord blood, umbilical cord, placenta and amnion are normally discarded at birth, they provide an easily accessible alternative source of stem cells. We review the potential and current status of the use of adult stem cells derived from the placenta or umbilical cord in therapeutic and toxicological applications.« less

Pluripotent stem cells and reprogrammed cells in farm animals.

PubMed

Nowak-Imialek, Monika; Kues, Wilfried; Carnwath, Joseph W; Niemann, Heiner

2011-08-01

Pluripotent cells are unique because of their ability to differentiate into the cell lineages forming the entire organism. True pluripotent stem cells with germ line contribution have been reported for mice and rats. Human pluripotent cells share numerous features of pluripotentiality, but confirmation of their in vivo capacity for germ line contribution is impossible due to ethical and legal restrictions. Progress toward derivation of embryonic stem cells from domestic species has been made, but the derived cells were not able to produce germ line chimeras and thus are termed embryonic stem-like cells. However, domestic animals, in particular the domestic pig (Sus scrofa), are excellent large animals models, in which the clinical potential of stem cell therapies can be studied. Reprogramming technologies for somatic cells, including somatic cell nuclear transfer, cell fusion, in vitro culture in the presence of cell extracts, in vitro conversion of adult unipotent spermatogonial stem cells into germ line derived pluripotent stem cells, and transduction with reprogramming factors have been developed with the goal of obtaining pluripotent, germ line competent stem cells from domestic animals. This review summarizes the present state of the art in the derivation and maintenance of pluripotent stem cells in domestic animals.

Effect of chondrocyte-derived early extracellular matrix on chondrogenesis of placenta-derived mesenchymal stem cells.

PubMed

Park, Yong-Beom; Seo, Sinji; Kim, Jin-A; Heo, Jin-Chul; Lim, Young-Cheol; Ha, Chul-Won

2015-06-24

The extracellular matrix (ECM) surrounding cells contains a variety of proteins that provide structural support and regulate cellular functions. Previous studies have shown that decellularized ECM isolated from tissues or cultured cells can be used to improve cell differentiation in tissue engineering applications. In this study we evaluated the effect of decellularized chondrocyte-derived ECM (CDECM) on the chondrogenesis of human placenta-derived mesenchymal stem cells (hPDMSCs) in a pellet culture system. After incubation with or without chondrocyte-derived ECM in chondrogenic medium for 1 or 3 weeks, the sizes and wet masses of the cell pellets were compared with untreated controls (hPDMSCs incubated in chondrogenic medium without chondrocyte-derived ECM). In addition, histologic analysis of the cell pellets (Safranin O and collagen type II staining) and quantitative reverse transcription-PCR analysis of chondrogenic markers (aggrecan, collagen type II, and SOX9) were carried out. Our results showed that the sizes and masses of hPDMSC pellets incubated with chondrocyte-derived ECM were significantly higher than those of untreated controls. Differentiation of hPDMSCs (both with and without chondrocyte-derived ECM) was confirmed by Safranin O and collagen type II staining. Chondrogenic marker expression and glycosaminoglycan (GAG) levels were significantly higher in hPDMSC pellets incubated with chondrocyte-derived ECM compared with untreated controls, especially in cells precultured with chondrocyte-derived ECM for 7 d. Taken together, these results demonstrate that chondrocyte-derived ECM enhances the chondrogenesis of hPDMSCs, and this effect is further increased by preculture with chondrocyte-derived ECM. This preculture method for hPDMSC chondrogenesis represents a promising approach for cartilage tissue engineering.

Information on Stem Cell Research

MedlinePlus

... of stem cells share similar properties there are differences as well. For example, ES cells and iPS cells are able to differentiate into any type of cell, whereas adult stem cells are more restricted in their potential. The promise of all stem cells for use ...

The Development of Stem Cell-Based Treatment for Liver Failure.

PubMed

Zhu, Tiantian; Li, Yuwen; Guo, Yusheng; Zhu, Chuanlong

2017-01-01

Liver failure is a devastating clinical syndrome with a persistently mortality rate despite advanced care. Orthotopic liver transplantation protected patients from hepatic failure. Yet, limitations including postoperative complications, high costs, and shortages of donor organs defect its application. The development of stem cell therapy complements the deficiencies of liver transplantation, due to the inherent ability of stem cells to proliferate and differentiate. Understand the source of stem cells, as well as the advantages and disadvantages of stem cell therapy. Based on published papers, we discussed the cell sources and therapeutic effect of stem cells. We also summarized the pros and cons, as well as optimization of stem cell-based treatment. Finally outlook future prospects of stem cell therapy. Stem cells may be harvested from a variety of human tissues, and then used to promote the convalescence of hepatocellular function. The emergence of the co-cultured system, tissueengineered technology and genetic modfication has further enhanced the functionality of stem cells. However, the tumorigenicity, the low survival rate and the scarcity of long-term treatment effect are obstacles for the further development of stem cell therapy. In this review, we highlight current research findings and present the future prospects in the area of stem cell-based treatment for liver failure. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

76 FR 11491 - Advisory Council on Blood Stem Cell Transplantation; Request for Nominations for Voting Members

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... Council on Blood Stem Cell Transplantation; Request for Nominations for Voting Members AGENCY: Health... on Blood Stem Cell Transplantation. The Advisory Council on Blood Stem Cell Transplantation was...: Nominations should be submitted to the Executive Secretary, Advisory Council on Blood Stem Cell...

3 CFR - Guidelines for Human Stem Cell Research

Code of Federal Regulations, 2010 CFR

2010-01-01

... 3 The President 1 2010-01-01 2010-01-01 false Guidelines for Human Stem Cell Research Presidential Documents Other Presidential Documents Memorandum of July 30, 2009 Guidelines for Human Stem Cell Research..., scientifically worthy human stem cell research, including human embryonic stem cell research, to the extent...

Aging, metabolism and stem cells: Spotlight on muscle stem cells.

PubMed

García-Prat, Laura; Muñoz-Cánoves, Pura

2017-04-15

All tissues and organs undergo a progressive regenerative decline as they age. This decline has been mainly attributed to loss of stem cell number and/or function, and both stem cell-intrinsic changes and alterations in local niches and/or systemic environment over time are known to contribute to the stem cell aging phenotype. Advancing in the molecular understanding of the deterioration of stem cell cells with aging is key for targeting the specific causes of tissue regenerative dysfunction at advanced stages of life. Here, we revise exciting recent findings on why stem cells age and the consequences on tissue regeneration, with a special focus on regeneration of skeletal muscle. We also highlight newly identified common molecular pathways affecting diverse types of aging stem cells, such as altered proteostasis, metabolism, or senescence entry, and discuss the questions raised by these findings. Finally, we comment on emerging stem cell rejuvenation strategies, principally emanating from studies on muscle stem cells, which will surely burst tissue regeneration research for future benefit of the increasing human aging population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

In vitro spatially organizing the differentiation in individual multicellular stem cell aggregates.

PubMed

Qi, Hao; Huang, Guoyou; Han, Yu Long; Lin, Wang; Li, Xiujun; Wang, Shuqi; Lu, Tian Jian; Xu, Feng

2016-01-01

With significant potential as a robust source to produce specific somatic cells for regenerative medicine, stem cells have attracted increasing attention from both academia and government. In vivo, stem cell differentiation is a process under complicated regulations to precisely build tissue with unique spatial structures. Since multicellular spheroidal aggregates of stem cells, commonly called as embryoid bodies (EBs), are considered to be capable of recapitulating the events in early stage of embryonic development, a variety of methods have been developed to form EBs in vitro for studying differentiation of embryonic stem cells. The regulation of stem cell differentiation is crucial in directing stem cells to build tissue with the correct spatial architecture for specific functions. However, stem cells within the three-dimensional multicellular aggregates undergo differentiation in a less unpredictable and spatially controlled manner in vitro than in vivo. Recently, various microengineering technologies have been developed to manipulate stem cells in vitro in a spatially controlled manner. Herein, we take the spotlight on these technologies and researches that bring us the new potential for manipulation of stem cells for specific purposes.

Stem cells in nephrology: present status and future.

PubMed

Watorek, Ewa; Klinger, Marian

2006-01-01

Stem cell biology is currently developing rapidly because of the potential therapeutic utility of stem cells. The ability to acquire any desired phenotype raises hope for regenerative therapies. Manipulation of these cells is a potentially valuable tool; however, the mechanisms of stem cell differentiation and plasticity are currently beyond our control. In the field of nephrology, the presence of adult kidney stem cells has been debated. Renal adult stem cells may be descendants of some early kidney progenitors, or may be derived from bone marrow. Evidence of a hematopoietic stem-cell contribution to renal repair encourages the possibility of bone marrow or stem cell transplantation as a means of treating autoimmune glomerulopathies. The transplantation of fetal kidney tissue containing renal progenitors, which then develop into functional nephrons, is a step towards renal regeneration. According to recent reports, the development of functional nephrons from human mesenchymal stem cells in rodent whole-embryo culture is possible. Establishing in vitro self organs from autologous stem cells would be a promising therapeutic solution in light of the shortage of allogenic organs and the unresolved problem of chronic allograft rejection.

Socializing with the neighbors: stem cells and their niche.

PubMed

Fuchs, Elaine; Tumbar, Tudorita; Guasch, Geraldine

2004-03-19

The potential of stem cells in regenerative medicine relies upon removing them from their natural habitat, propagating them in culture, and placing them into a foreign tissue environment. To do so, it is essential to understand how stem cells interact with their microenvironment, the so-called stem cell niche, to establish and maintain their properties. In this review, we examine adult stem cell niches and their impact on stem cell biology.

Stem Cells News Update: A Personal Perspective

PubMed Central

Wong, SC

2013-01-01

This article is a follow-up to a previous Commentary published in 2011. It updates some of the events mentioned in that Commentary and continues with more interesting and exciting news on stem cell research and the emerging field of Regenerative Medicine. Some of the news includes: 1) the 2012 Nobel Prize for Medicine awarded to John B. Gurdon and Shinya Yamanaka; 2) the cloning of human embryonic stem cells; 3) the continued search for truly pluripotent adult stem cells via in vitro and in vivo protocols; 4) the breakthrough in organ replacements; 5) the global stem cell race; 6) the global stem cell cryo-preservation business; 7) the worldwide stem cell donor registries, and 8) the issue of government regulation on stem cell therapy. PMID:24778557

Stem cells news update: a personal perspective.

PubMed

Wong, Sc

2013-12-01

This article is a follow-up to a previous Commentary published in 2011. It updates some of the events mentioned in that Commentary and continues with more interesting and exciting news on stem cell research and the emerging field of Regenerative Medicine. Some of the news includes: 1) the 2012 Nobel Prize for Medicine awarded to John B. Gurdon and Shinya Yamanaka; 2) the cloning of human embryonic stem cells; 3) the continued search for truly pluripotent adult stem cells via in vitro and in vivo protocols; 4) the breakthrough in organ replacements; 5) the global stem cell race; 6) the global stem cell cryo-preservation business; 7) the worldwide stem cell donor registries, and 8) the issue of government regulation on stem cell therapy.

Platelet-rich plasma derived growth factors contribute to stem cell differentiation in musculoskeletal regeneration

NASA Astrophysics Data System (ADS)

Qian, Yun; Han, Qixin; Chen, Wei; Song, Jialin; Zhao, Xiaotian; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

2017-10-01

Stem cell treatment and platelet-rich plasma (PRP) therapy are two significant issues in regenerative medicine. Stem cells such as bone marrow mesenchymal stem cells, adipose-derived stem cells and periodontal ligament stem cells can be successfully applied in the field of tissue regeneration. PRP, a natural product isolated from whole blood, can secrete multiple growth factors (GFs) for regulating physiological activities. These GFs can stimulate proliferation and differentiation of different stem cells in injury models. Therefore, combination of both agents receives wide expectations in regenerative medicine, especially in bone, cartilage and tendon repair. In this review, we thoroughly discussed the interaction and underlying mechanisms of platelet-rich plasma derived growth factors with stem cells, and assessed their functions in cell differentiation for musculoskeletal regeneration.

Elements of the niche for adult stem cell expansion

PubMed Central

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells. PMID:28890779

Platelet-Rich Plasma Derived Growth Factors Contribute to Stem Cell Differentiation in Musculoskeletal Regeneration.

PubMed

Qian, Yun; Han, Qixin; Chen, Wei; Song, Jialin; Zhao, Xiaotian; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

2017-01-01

Stem cell treatment and platelet-rich plasma (PRP) therapy are two significant issues in regenerative medicine. Stem cells such as bone marrow mesenchymal stem cells, adipose-derived stem cells and periodontal ligament stem cells can be successfully applied in the field of tissue regeneration. PRP, a natural product isolated from whole blood, can secrete multiple growth factors (GFs) for regulating physiological activities. These GFs can stimulate proliferation and differentiation of different stem cells in injury models. Therefore, combination of both agents receives wide expectations in regenerative medicine, especially in bone, cartilage and tendon repair. In this review, we thoroughly discussed the interaction and underlying mechanisms of PRP derived GFs with stem cells, and assessed their functions in cell differentiation for musculoskeletal regeneration.

Elements of the niche for adult stem cell expansion.

PubMed

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells.

Stem cell maintenance by manipulating signaling pathways: past, current and future

PubMed Central

Chen, Xi; Ye, Shoudong; Ying, Qi-Long

2015-01-01

Pluripotent stem cells only exist in a narrow window during early embryonic development, whereas multipotent stem cells are abundant throughout embryonic development and are retainedin various adult tissues and organs. While pluripotent stem cell lines have been established from several species, including mouse, rat, and human, it is still challenging to establish stable multipotent stem cell lines from embryonic or adult tissues. Based on current knowledge, we anticipate that by manipulating extrinsic and intrinsic signaling pathways, most if not all types of stem cells can be maintained in a long-term culture. In this article, we summarize current culture conditions established for the long-term maintenance of authentic pluripotent and multipotent stem cells and the signaling pathways involved. We also discuss the general principles of stem cell maintenance and propose several strategies on the establishment of novel stem cell lines through manipulation of signaling pathways. [BMB Reports 2015; 48(12): 668-676] PMID:26497581

Stem cells and female reproduction.

PubMed

Du, Hongling; Taylor, Hugh S

2009-02-01

Several recent findings in stem cell biology have resulted in new opportunities for the treatment of reproductive disease. Endometrial regeneration can be driven by bone marrow derived stem cells. This finding has potential implications for the treatment of uterine disorders. It also supports a new theory for the etiology of endometriosis. The ovaries have been shown to contain stem cells that form oocytes in adults and can be cultured in vitro to develop mature oocytes. Stem cells from the fetus have been demonstrated to lead to microchimerism in the mother and implicated in several maternal diseases. Additionally the placenta may be another source of hematopoietic stem cell. Finally endometrial derived stem cells have been demonstrated to differentiate into non-reproductive tissues. While we are just beginning to understand stem cells and many key questions remain, the potential advantages of stem cells in reproductive biology and medicine are apparent.

The potential of nanofibers in tissue engineering and stem cell therapy.

PubMed

Gholizadeh-Ghaleh Aziz, Shiva; Gholizadeh-Ghaleh Aziz, Sara; Akbarzadeh, Abolfazl

2016-08-01

Electrospinning is a technique in which materials in solution are shaped into continuous nano- and micro-sized fibers. Combining stem cells with biomaterial scaffolds and nanofibers affords a favorable approach for bone tissue engineering, stem cell growth and transfer, ocular surface reconstruction, and treatment of congenital corneal diseases. This review seeks to describe the current examples of the use of scaffolds in stem cell therapy. Stem cells are classified as adult or embryonic stem (ES) cells, and the advantages and drawbacks of each group are detailed. The nanofibers and scaffolds are further classified in Tables I and II , which describe specific examples from the literature. Finally, the current applications of biomaterial scaffolds containing stem cells for tissue engineering applications are presented. Overall, this review seeks to give an overview of the biomaterials available for use in combination with stem cells, and the application of nanofibers in stem cell therapy.

The stem cell patent landscape as relevant to cancer vaccines.

PubMed

Wang, Shyh-Jen

2011-10-01

Cancer vaccine targeting cancer stem cells is proposed to serve as a potent immunotherapy. Thus, it would be useful to examine the main trends in stem cell patenting activity as a guide for those seeking to develop such cancer vaccines. We found that a substantial number of stem cell patents were granted up to the end of 2010, including ~2000 issued in the US. Many of these have been filed since 2001, including 7,551 applications in the US. Stem cell development, as evidenced by the numbers of PubMed articles, has matured steadily in recent years. However, the other metrics, such as the number of patent applications, the technology-science linkage and the number of patent assignees, have been stagnant. Moreover, the ownership of stem cell patents is still quiet fragmented across multiple organizations, and the number of stem cell patent assignees from the business sector has not increased significantly. Academic and nonprofit institutions not only account for a large share of stem cell patents but also apply for patents continually. Based on this analysis, the strength of stem cell resources seems to remain stagnant in recent years due to the ban on government funding of embryonic stem cell research. Furthermore, the patent prosecution or technical barriers in the field of stem cells would be another main reason that the number of US-issued stem cell patents for each application have been in gradual decline since 2000. Therefore, we consider stem cell technology to still be under development.

Fraudsters operate and officialdom turns a blind eye: a proposal for controlling stem cell therapy in China.

PubMed

Jiang, Li; Dong, Bing He

2016-09-01

Stem cell tourism-the flow of patients from home countries to destination countries to obtain stem cell treatment-is a growing business in China. Many concerns have been raised regarding fraudsters that operate unsafe stem cell therapies and an officialdom that turns a blind eye to the questionable technology. The Chinese regulatory approach to stem cell research is based on Guidelines and Administrative Measures, rather than legislation, and may have no binding force on certain institutions, such as military hospitals. There is no liability and traceability system and no visible set of penalties for non-compliance in the stem cell legal framework. In addition to the lack of safety and efficacy systems in the regulations, no specific expert authority has been established to monitor stem cell therapy to date. Recognizing the global nature of stem cell tourism, this article argues that resolving stem cell tourism issues may require not only the Chinese government but also an international mechanism for transparency and ethical oversight. A stringent set of international regulations that govern stem cell therapies can encourage China to improve stem cell regulation and enforcement to fulfill its obligations. Through an international consensus, a minimum standard for clinical stem cell research and a central enforcement system will be provided. As a result, rogue clinics that conduct unauthorized stem cell therapies can be penalized, and countries that are reluctant to implement the reconciled regulations should be sanctioned.

Epigenetic Control of Stem Cell Potential During Homeostasis, Aging, and Disease

PubMed Central

Beerman, Isabel; Rossi, Derrick J.

2015-01-01

Stem cell decline is an important cellular driver of aging-associated pathophysiology in multiple tissues. Epigenetic regulation is central to establishing and maintaining stem cell function, and emerging evidence indicates that epigenetic dysregulation contributes to the altered potential of stem cells during aging. Unlike terminally differentiated cells, the impact of epigenetic dysregulation in stem cells is propagated beyond self; alterations can be heritably transmitted to differentiated progeny, in addition to being perpetuated and amplified within the stem cell pool through self-renewal divisions. This review focuses on recent studies examining epigenetic regulation of tissue-specific stem cells in homeostasis, aging, and aging-related disease. PMID:26046761

Attitude of A Sample of Iranian Researchers toward The Future of Stem Cell Research.

PubMed

Lotfipanah, Mahdi; Azadeh, Fereydoon; Totonchi, Mehdi; Omani-Samani, Reza

2018-10-01

Stem cells that have unlimited proliferation potential as well as differentiation potency are considered to be a promising future treatment method for incurable diseases. The aim of the present study is to evaluate the future trend of stem cell researches from researchers' viewpoints. This was a cross-sectional descriptive study on researchers involved in stem cell research at Royan Institute. We designed a questionnaire using a qualitative study based on expert opinion and a literature review. Content validity was performed using three rounds of the Delphi method with experts. Face validity was undertaken by a Persian literature expert and a graphics designer. The questionnaire was distributed among 150 researchers involved in stem cell studies in Royan Institute biology laboratories. We collected 138 completed questionnaires. The mean age of participants was 31.13 ± 5.8 years; most (60.9%) were females. Participants (76.1%) considered the budget to be the most important issue in stem cell research, 79.7% needed financial support from the government, and 77.5% felt that charities could contribute substantially to stem cell research. A total of 90.6% of participants stated that stem cells should lead to commercial usage which could support future researches (86.2%). The aim of stem cell research was stipulated as increasing health status of the society according to 92.8% of the participants. At present, among cell types, importance was attached to cord blood and adult stem cells. Researchers emphasized the importance of mesenchymal stem cells (MSCs) rather than hematopoietic stem cells (HSCs, 57.73%). The prime priorities were given to cancer so that stem cell research could be directed to sphere stem cell research whereas the least preference was given to skin research. Regenerative medicine is considered the future of stem cell research with emphasis on application of these cells, especially in cancer treatment. Copyright© by Royan Institute. All rights reserved.

Translating stem cell research: challenges at the research frontier.

PubMed

Magnus, David

2010-01-01

This paper will address the translation of basic stem cell research into clinical research. While "stem cell" trials are sometimes used to describe established practices of bone marrow transplantation or transplantation of primary cells derived from bone marrow, for the purposes of this paper, I am primarily focusing on stem cell trials which are far less established, including use of hESC derived stem cells. The central ethical challenges in stem cell clinical trials arise in frontier research, not in standard, well-established areas of research.

Murine hepatocellular carcinoma derived stem cells reveal epithelial-to-mesenchymal plasticity.

PubMed

Jayachandran, Aparna; Shrestha, Ritu; Dhungel, Bijay; Huang, I-Tao; Vasconcelos, Marianna Yumi Kawashima; Morrison, Brian J; Ramlogan-Steel, Charmaine A; Steel, Jason C

2017-09-26

To establish a model to enrich and characterize stem-like cells from murine normal liver and hepatocellular carcinoma (HCC) cell lines and to further investigate stem-like cell association with epithelial-to-mesenchymal transition (EMT). In this study, we utilized a stem cell conditioned serum-free medium to enrich stem-like cells from mouse HCC and normal liver cell lines, Hepa 1-6 and AML12, respectively. We isolated the 3-dimensional spheres and assessed their stemness characteristics by evaluating the RNA levels of stemness genes and a cell surface stem cell marker by quantitative reverse transcriptase-PCR (qRT-PCR). Next, we examined the relationship between stem cells and EMT using qRT-PCR. Three-dimensional spheres were enriched by culturing murine HCC and normal hepatocyte cell lines in stem cell conditioned serum-free medium supplemented with epidermal growth factor, basic fibroblast growth factor and heparin sulfate. The 3-dimensional spheres had enhanced stemness markers such as Klf4 and Bmi1 and hepatic cancer stem cell (CSC) marker Cd44 compared to parental cells grown as adherent cultures. We report that epithelial markers E-cadherin and ZO-1 were downregulated, while mesenchymal markers Vimentin and Fibronectin were upregulated in 3-dimensional spheres. The 3-dimensional spheres also exhibited changes in expression of Snai , Zeb and Twist family of EMT transcription factors. Our novel method successfully enriched stem-like cells which possessed an EMT phenotype. The isolation and characterization of murine hepatic CSCs could establish a precise target for the development of more effective therapies for HCC.

Wnt/β-Catenin Signaling Determines the Vasculogenic Fate of Postnatal Mesenchymal Stem Cells.

PubMed

Zhang, Zhaocheng; Nör, Felipe; Oh, Min; Cucco, Carolina; Shi, Songtao; Nör, Jacques E

2016-06-01

Vasculogenesis is the process of de novo blood vessel formation observed primarily during embryonic development. Emerging evidence suggest that postnatal mesenchymal stem cells are capable of recapitulating vasculogenesis when these cells are engaged in tissue regeneration. However, the mechanisms underlining the vasculogenic differentiation of mesenchymal stem cells remain unclear. Here, we used stem cells from human permanent teeth (dental pulp stem cells [DPSC]) or deciduous teeth (stem cells from human exfoliated deciduous teeth [SHED]) as models of postnatal primary human mesenchymal stem cells to understand mechanisms regulating their vasculogenic fate. GFP-tagged mesenchymal stem cells seeded in human tooth slice/scaffolds and transplanted into immunodeficient mice differentiate into human blood vessels that anastomize with the mouse vasculature. In vitro, vascular endothelial growth factor (VEGF) induced the vasculogenic differentiation of DPSC and SHED via potent activation of Wnt/β-catenin signaling. Further, activation of Wnt signaling is sufficient to induce the vasculogenic differentiation of postnatal mesenchymal stem cells, while Wnt inhibition blocked this process. Notably, β-catenin-silenced DPSC no longer differentiate into endothelial cells in vitro, and showed impaired vasculogenesis in vivo. Collectively, these data demonstrate that VEGF signaling through the canonical Wnt/β-catenin pathway defines the vasculogenic fate of postnatal mesenchymal stem cells. Stem Cells 2016;34:1576-1587. © 2016 AlphaMed Press.

MiR-7 inhibited peripheral nerve injury repair by affecting neural stem cells migration and proliferation through cdc42.

PubMed

Zhou, Nan; Hao, Shuang; Huang, Zongqiang; Wang, Weiwei; Yan, Penghui; Zhou, Wei; Zhu, Qihang; Liu, Xiaokang

2018-01-01

Objective Neural stem cells play an important role in the recovery and regeneration of peripheral nerve injury, and the microRNA-7 (miR-7) regulates differentiation of neural stem cells. This study aimed to explore the role of miR-7 in neural stem cells homing and proliferation and its influence on peripheral nerve injury repair. Methods The mice model of peripheral nerve injury was created by segmental sciatic nerve defect (sciatic nerve injury), and neural stem cells treatment was performed with a gelatin hydrogel conduit containing neural stem cells inserted into the sciatic nerve injury mice. The Sciatic Function Index was used to quantify sciatic nerve functional recovery in the mice. The messenger RNA and protein expression were detected by reverse transcription polymerase chain reaction and Western blot, respectively. Luciferase reporter assay was used to confirm the binding between miR-7 and the 3'UTR of cell division cycle protein 42 (cdc42). The neural stem cells migration and proliferation were analyzed by transwell assay and a Cell-LightTM EdU DNA Cell Proliferation kit, respectively. Results Neural stem cells treatment significantly promoted nerve repair in sciatic nerve injury mice. MiR-7 expression was decreased in sciatic nerve injury mice with neural stem cells treatment, and miR-7 mimic transfected into neural stem cells suppressed migration and proliferation, while miR-7 inhibitor promoted migration and proliferation. The expression level and effect of cdc42 on neural stem cells migration and proliferation were opposite to miR-7, and the luciferase reporter assay proved that cdc42 was a target of miR-7. Using co-transfection into neural stem cells, we found pcDNA3.1-cdc42 and si-cdc42 could reverse respectively the role of miR-7 mimic and miR-7 inhibitor on neural stem cells migration and proliferation. In addition, miR-7 mimic-transfected neural stem cells could abolish the protective role of neural stem cells on peripheral nerve injury. Conclusion MiR-7 inhibited peripheral nerve injury repair by affecting neural stem cells migration and proliferation through cdc42.