Mammalian stem cells

Algal Cells-Derived Extracellular Vesicles: A Review With Special Emphasis on Their Antimicrobial Effects

Extracellular vesicles (EVs) originated from different cells of approximately all kinds of organisms, recently got more attention because of their potential in the treatment of diseases and reconstructive medicine. To date, lots of studies have been performed on mammalian-derived vesicles, but little attention has been paid to algae and marine cells as valuable sources of EVs. Proving the promising role of EVs in medicine requires sufficient resources to produce qualified microvesicles. Algae, same as its other sister groups, such as plants, have stem cells and stem cell niches. Previous studies showed the EVs in plants and marine cells. So, this study was set out to talk about algal extracellular vesicles. EVs play a major role in cell-to-cell communication to convey molecules, such as RNA/DNA, metabolites, proteins, and lipids within. The components of EVs depends on the origin of the primitive cells or tissues and the isolation method. Sufficient resources are needed to produce high-quality, stable, and compatible EVs as a drug or drug delivery system. Plant stem cells have great potential as a new controllable resource for the production of EVs. The EVs secreted from stem cells can easily be extracted from the cell culture medium and evaluated for medicinal uses. In this review, the aim is to introduce algae stem cells as well as EVs derived from algal cells. In the following, the production of the EVs¸ the properties of EVs extracted from these sources and their antimicrobial effects will be discussed.

Cytology, function and dynamics of stem and progenitor cells in decapod crustaceans

Stem cells play key roles in development, tissue homeostasis, regeneration, ageing and diseases. Comprehensive reviews on stem cells are available for the determinately growing mammals and insects and some lower invertebrates like hydra but are rare for larger, indeterminately growing invertebrates that can live for many decades. This paper reviews the cytology, function and dynamics of stem and progenitor cells in the decapod crustaceans, a species-rich and ecologically and economically important animal group that includes mainly indeterminate growers but also some determinate growers. Further advantages of decapods for stem cell research are almost 1000-fold differences in body size and longevity, the regeneration of damaged appendages and the virtual absence of age-related diseases and tumours in the indeterminately growing species. The available data demonstrate that the Decapoda possess a remarkable variety of structurally and functionally different stem cells in embryos and larvae, and in the epidermis, musculature, haematopoietic tissue, heart, brain, hepatopancreas, olfactory sense organs and gonads of adults. Some of these seem to be rather continuously active over a lifetime but others are cyclically activated and silenced in periods of days, weeks and years, depending on the specific organ and function. Stem cell proliferation is triggered by signals related to development, moulting, feeding, reproduction, injury, infection, environmental enrichment and social status. Some regulatory pathways have already been identified, including the evolutionarily conserved GATA-binding and runt-domain transcription factors, the widespread neurotransmitter serotonin, the arthropod-specific hormone 20-hydroxyecdysone and the novel astakine growth factors. Knowledge of stem cells in decapods primarily refines our picture on the development, growth and maintenance of tissues and organs in this animal group. Cultured decapod stem cells have good potential for toxicity testing and virus research with practical relevance for aquaculture. Knowledge of stem cells in decapods also broadens our understanding of the evolution of stem cells and regeneration in the animal kingdom. The stem cells of long-lived, indeterminately growing decapods may hold the key to understanding how stem and progenitor cells function into old age without adverse side effects, possibly evoking new ideas for the development of anti-ageing and anti-cancer treatments in humans.

Effects of Salvia miltorrhiza in neural differentiation of rat mesenchymal stem cells with optimized protocol

AIM OF THE STUDY

The present study was aimed to explore the effects of Salvia miltorrhiza in inducing rMSCs to differentiate into functional neurons.

MATERIALS AND METHODS

rMSCs were isolated and cultured in vitro, then Salvia miltorrhiza was added to induce rMSCs to differentiate repeatedly for 5 times with an optimized protocol, and neurophysiological functions such as action potential, endocytosis and exocytosis of the induced cells were investigated.

RESULTS

About 98% of rMSCs expressed markers related to neural stem cells after treatment with preinduction medium, but they remained fibroform, the classical morphological state of MSCs, after exposure to induction medium for 2h, and the induced cells showed a neural shape. Next, fetal bovine serum (FBS) was added into the induction medium, transforming the neuron-like cells into fibroform cells. Finally, after exposure to induction medium, the cells could be transformed into neuron-like cells again. After the procedure was repeated 5 times, the induced cells displayed a classical neural shape and more than 95% of them expressed neural markers, including TUJ-1, NF and synaptophysin. Furthermore, the induced cells displayed neurophysiological functions, as characterized by action potential, endocytosis and exocytosis in response to a solution with a high concentration of potassium (K(+)).

CONCLUSION

Salvia miltorrhiza can induce rMSCs to differentiate into neurons with neurophysiological functions efficiently by an optimized protocol.

Transcriptomes and Proteomes of Dental Follicle Cells

Ectomesenchymal dental stem cells could be feasible tools for dental tissue engineering. Dental follicle cells are a promising example, since they are capable of differentiation into various dental tissue cells, such as osteoblasts or cementoblasts. However, cellular mechanisms of cell proliferation and differentiation are not understood in detail. Basic knowledge of these molecular processes may shorten the time before ectomesenchymal dental stem cells can be exploited for bone augmentation in regenerative medicine. Recent developments in proteomics and transcriptomics have made information about genome-wide expression profiles accessible, which can aid in clarifying molecular mechanisms of cells. This review describes the transcriptomes and proteomes of dental follicle cells before and after differentiation, and compares them with differentially expressed populations from dental tissue or bone marrow.

Training the next generation of pluripotent stem cell researchers

Human pluripotent stem cells (PSCs) have the unique properties of being able to proliferate indefinitely in their undifferentiated state and of being able to differentiate into any somatic cell type. These cells are thus posited to be extremely useful for furthering our understanding of both normal and abnormal human development, providing a human cell preparation that can be used to screen for new reagents or therapeutic agents, and generating large numbers of differentiated cells that can be used for transplantation purposes. PSCs in culture have a specific morphology and they express characteristic surface antigens and nuclear transcription factors; thus, PSC culture is very specific and requires a core skill set for successful propagation of these unique cells. Specialized PSC training courses have been extremely valuable in seeding the scientific community with researchers that possess this skill set.

The promoter of the oocyte-specific gene, Gdf9, is active in population of cultured mouse embryonic stem cells with an oocyte-like phenotype

The study of germ cell-specific gene regulation in vitro is challenging. Here we report that the promoter of the oocyte-specific gene, Gdf9, is active in a population of cultured murine embryonic stem cells (ES) which have a phenotype resembling oocytes. The promoter region of the murine Gdf9 coupled to enhanced green fluorescent protein (eGFP) was stably transfected into XX mouse ES cells. eGFP was expressed only in oocytes of chimeric mice generated from the transfected XX ES cells. The transfected ES cells were examined when cultured on feeder layers or as embryoid bodies. Large eGFP-positive cells, surrounded by a structure resembling a zona pellucida appeared transiently in cultures of the ES cells on feeder layers. Surprisingly, they were detectable on days 1 and 2 of culture but virtually absent on day 3. Addition of leukemia inhibitory factor (LIF) to the media significantly increased the number of eGFP-positive cels resembling oocytes. Quantitative-time PCR demonstrated a parallel increase in Gdf9 and Zp3 mRNA with changes in the abundance of eGFP-positive cells. In embryoid body cultures, eGFP-positive cells appeared transiently and then re-appeared in regional clusters after 30-45 days of culture. These findings demonstrate that a population of cultured murine ES cells contain the transcriptional machinery to drive expression of an oocyte-specific gene, and that those cells phenotypically resemble oocytes.

Differentiation of neural lineage cells from human pluripotent stem cells

Human pluripotent stem cells have the unique properties of being able to proliferate indefinitely in their undifferentiated state and to differentiate into any somatic cell type. These cells are thus posited to be extremely useful for furthering our understanding of both normal and abnormal human development, providing a human cell preparation that can be used to screen for new reagents or therapeutic agents, and generating large numbers of differentiated cells that can be used for transplantation purposes. Critical among the applications for the latter are diseases and injuries of the nervous system, medical approaches to which have been, to date, primarily palliative in nature. Differentiation of human pluripotent stem cells into cells of the neural lineage, therefore, has become a central focus of a number of laboratories. This has resulted in the description in the literature of several dozen methods for neural cell differentiation from human pluripotent stem cells. Among these are methods for the generation of such divergent neural cells as dopaminergic neurons, retinal neurons, ventral motoneurons, and oligodendroglial progenitors. In this review, we attempt to fully describe most of these methods, breaking them down into five basic subdivisions: (1) starting material, (2) induction of loss of pluripotency, (3) neural induction, (4) neural maintenance and expansion, and (5) neuronal/glial differentiation. We also show data supporting the concept that undifferentiated human pluripotent stem cells appear to have an innate neural differentiation potential. In addition, we evaluate data comparing and contrasting neural stem cells differentiated from human pluripotent stem cells with those derived directly from the human brain.

Stand der humanen dentalen Stammzellforschung

This review article arranges the current results of stem cell biology for their use in dentistry. There are different types of stem cells, which are applicable for dental treatments. The use of embryonic stem cells, whose possibilities for breeding an artificial tooth were hardly evaluated, is however ethically precarious. On the other side the ethically harmless adult stem cells, which were isolated for example from bone marrow, were little examined for their capability of differentiation into dental tissues. Therefore their forthcoming use in dentistry is rather improbable. However, dental ectomesenchymal stem cells are more promising for dentistry in future. For example dental pulp stem cells (DPSCs) are capable to differentiate into dentin under in vitro conditions. Moreover it is possible to use periodontal ligament (PDL) stem cells and dental follicle precursors for periodontal tissue differentiations in vitro. Recently new populations of stem cells were isolated from the dental pulp and the PDL. These cells distinguish from the initially isolated DPSCs and PDL stem cells in growth and cell differentiation. Therefore stem cell markers are very important for the characterization of dental stem cells. A significant marker for dental stem cells is STRO-1, which is also a marker for bone marrow derived mesenchymal stem cells. Nonetheless dental stem cells are CD45 negative and they express rarely hematopoietic stem cell markers. These research results plead for the participation of dental stem cells in dental practice in future.

Stem cells adaptive network: mechanism and implications for evolution and disease development

During development, different cells and tissues acquire different programmes of gene expression, so that cells are related to each other through a somatic cells tree or cluster and adult pluripotential stem cells (PSC) may be defined as progenitors that we distinguish in four types according to their biological behaviour. This clustering may segregate specific pathways establishing spatial patterns of cell-cell communications. Thus, we suggest that normal somatic cells renewal is tributary of multipotential stem cells (MSC), while renewal of cells undergoing stress or abnormal death is tributary of PSC through specific pathway(s) from cluster, thus, defining the cell repertoire that will be produced. We also assume that PSC play a pivotal role in evolutionary and propose the theory of "internal clusters competition". According to the functional duality of stem cells (SC) we define a stem cells adaptive network (SCAN) which we believe is linked to the central clock and display two pathways. The diurnal pathway includes SC-somatic cells communications, while the nocturnal pathway includes inter-SC network. These alternate pathways could be activated or repressed as a consequence of change in the biological chirality. This new approach of SC may contribute to our understanding on how some diseases may develop including cancer which could be linked to "cluster illness", while demyelinating and systemic diseases could be related to "PSC locus illness" or "focalised SCAN disturbances" and it explains how any environment stress may act on organism evolution.