Amniotic fluid stem cells morph into a cardiovascular lineage: analysis of a chemically induced cardiac and vascular commitment

Mesenchymal Stem Cell Behavior under Microgravity: From Stress Response to a Premature Senescence

Mesenchymal stem cells are undifferentiated cells able to acquire different phenotypes under specific stimuli. Wharton's jelly is a tissue in the umbilical cord that contains mesenchymal stromal cells (MSCs) with a high plasticity and differentiation potential. Their regeneration capability is compromised by cell damage and aging. The main cause of cell damage is oxidative stress coming from an imbalance between oxidant and antioxidant species. Microgravity represents a stressing condition able to induce ROS production, ultimately leading to different subcellular compartment damages. Here, we analyzed molecular programs of stemness (Oct-4; SOX2; Nanog), cell senescence, p19, p21 (WAF1/CIP1), p53, and stress response in WJ-MSCs exposed to microgravity. From our results, we can infer that a simulated microgravity environment is able to influence WJ-MSC behavior by modulating the expression of stress and stemness-related genes, cell proliferation regulators, and both proapoptotic and antiapoptotic genes. Our results suggest a cellular adaptation addressed to survival occurring during the first hours of simulated microgravity, followed by a loss of stemness and proliferation capability, probably related to the appearance of a molecular program of senescence.

Natural Compounds and PCL Nanofibers: A Novel Tool to Counteract Stem Cell Senescence

Tissue homeostasis mainly depends on the activity of stem cells to replace damaged elements and restore tissue functions. Within this context, mesenchymal stem cells and fibroblasts are essential for maintaining tissue homeostasis in skin, in particular in the dermis. Modifications in collagen fibers are able to affect stem cell features. Skin properties can be significantly reduced after injuries or with aging, and stem cell niches, mainly comprising extracellular matrix (ECM), may be compromised. To this end, specific molecules can be administrated to prevent the aging process induced by UV exposure in the attempt to maintain a youngness phenotype. NanoPCL-M is a novel nanodevice able to control delivery of Mediterranean plant myrtle (Myrtus communis L.) extracts. In particular, we previously described that myrtle extracts, rich in bioactive molecules and nutraceuticals, were able to counteract senescence in adipose derived stem cells. In this study, we analyzed the effect of NanoPCL-M on skin stem cells (SSCs) and dermal fibroblasts in a dynamic cell culture model in order to prevent the effects of UV-induced senescence on proliferation and collagen depot. The BrdU assay results highlight the significantly positive effect of NanoPCL-M on the proliferation of both fibroblasts and SSCs. Our results demonstrate that-M is able to preserve SSCs features and collagen depot after UV-induced senescence, suggesting their capability to retain a young phenotype.

Small Molecule Treatments Improve Differentiation Potential of Human Amniotic Fluid Stem Cells

Human amniotic fluid stem cells (AFSC) are an exciting and very promising source of stem cells for therapeutic applications. In this study we investigated the effects of short-term treatments of small molecules to improve stem cell properties and differentiation capability. For this purpose, we used epigenetically active compounds, such as histone deacetylase inhibitors Trichostatin A (TSA) and sodium butyrate (NaBut), as well as multifunctional molecules of natural origin, such as retinoic acid (RA) and vitamin C (vitC). We observed that combinations of these compounds triggered upregulation of genes involved in pluripotency (KLF4, OCT4, NOTCH1, SOX2, NANOG, LIN28a, CMYC), but expression changes of these proteins were mild with only significant downregulation of Notch1. Also, some alterations in cell surface marker expression was established by flow cytometry with the most explicit changes in the expression of CD105 and CD117. Analysis of cellular energetics performed using Seahorse analyzer and assessment of gene expression related to cell metabolism and respiration (NRF1, HIF1α, PPARGC1A, ERRα, PKM, PDK1, LDHA, NFKB1, NFKB2, RELA, RELB, REL) revealed that small molecule treatments stimulate AFSCs toward a more energetically active phenotype. To induce cells to differentiate toward neurogenic lineage several different protocols including commercial supplements N2 and B27 together with RA were used and compared to the same differentiation protocols with the addition of a pre-induction step consisting of a combination of small molecules (vitC, TSA and RA). During differentiation the expression of several neural marker genes was analyzed (Nestin, MAP2, TUBB3, ALDH1L1, GFAP, CACNA1D, KCNJ12, KCNJ2, KCNH2) and the beneficial effect of small molecule treatment on differentiation potential was observed with upregulated gene expression. Differentiation was also confirmed by staining TUBB3, NCAM1, and Vimentin and assessed by secretion of BDNF. The results of this study provide valuable insights for the potential use of short-term small molecule treatments to improve stem cell characteristics and boost differentiation potential of AFSCs.

Human Umbilical Cord: Information Mine in Sex-Specific Medicine

Biological differences between sexes should be considered in all stages of research, as sexual dimorphism starts in utero leading to sex-specific fetal programming. In numerous biomedical fields, there is still a lack of stratification by sex despite primary cultured cells retaining memory of the sex and of the donor. The sex of donors in biological research must be known because variations in cells and cellular components can be used as endpoints, biomarkers and/or targets of pharmacological studies. This selective review focuses on the current findings regarding sex differences observed in the umbilical cord, a widely used source of research samples, both in the blood and in the circulating cells, as well as in the different cellular models obtainable from it. Moreover, an overview on sex differences in fetal programming is reported. As it emerges that the sex variable is still often forgotten in experimental models, we suggest that it should be mandatory to adopt sex-oriented research, because only awareness of these issues can lead to innovative research.

Smart Nanofibers with Natural Extracts Prevent Senescence Patterning in a Dynamic Cell Culture Model of Human Skin

Natural cosmetic products have recently re-emerged as a novel tool able to counteract skin aging and skin related damages. In addition, recently achieved progress in nanomedicine opens a novel approach yielding from combination of modern nanotechnology with traditional treatment for innovative pharmacotherapeutics. In the present study, we investigated the antiaging effect of a pretreatment with Myrtus communis natural extract combined with a polycaprolactone nanofibrous scaffold (NanoPCL-M) on skin cell populations exposed to UV. We set up a novel model of skin on a bioreactor mimicking a crosstalk between keratinocytes, stem cells and fibroblasts, as in skin. Beta-galactosidase assay, indicating the amount of senescent cells, and viability assay, revealed that fibroblasts and stem cells pretreated with NanoPCL-M and then exposed to UV are superimposable to control cells, untreated and unexposed to UV damage. On the other hand, cells only exposed to UV stress, without NanoPCL-M pretreatment, exhibited a significantly higher yield of senescent elements. Keratinocyte-based 3D structures appeared disjointed after UV-stress, as compared to NanoPCL-M pretreated samples. Gene expression analysis performed on different senescence associated genes, revealed the activation of a molecular program of rejuvenation in stem cells pretreated with NanoPCL-M and then exposed to UV. Altogether, our results highlight a future translational application of NanoPCL-M to prevent skin aging.

Tuning Adipogenic Differentiation in ADSCs by Metformin and Vitamin D: Involvement of miRNAs

Fat tissue represents an important source of adipose-derived stem cells (ADSCs), which can differentiate towards several phenotypes under certain stimuli. Definite molecules as vitamin D are able to influence stem cell fate, acting on the expression of specific genes. In addition, miRNAs are important modulating factors in obesity and numerous diseases. We previously identified specific conditioned media able to commit stem cells towards defined cellular phenotypes. In the present paper, we aimed at evaluating the role of metformin on ADSCs differentiation. In particular, ADSCs were cultured in a specific adipogenic conditioned medium (MD), in the presence of metformin, alone or in combination with vitamin D. Our results showed that the combination of the two compounds is able to counteract the appearance of an adipogenic phenotype, indicating a feedforward regulation on vitamin D metabolism by metformin, acting on CYP27B1 and CYP3A4. We then evaluated the role of specific epigenetic modulating genes and miRNAs in controlling stem cell adipogenesis. The combination of the two molecules was able to influence stem cell fate, by modulating the adipogenic phenotype, suggesting their possible application in clinical practice in counteracting uncontrolled lipogenesis and obesity-related diseases.

Isolating stem cells from skin: designing a novel highly efficient non-enzymatic approach

Stem cells are undifferentiated elements capable to acquire a specific cellular phenotype under the influence of specific stimuli, thus being involved in tissue integrity and maintenance. In the skin tissue self-renewal and wound healing after injury is a complex process, especially in adulthood, due to the aging process and the continuous exposure to damaging agents. The importance of stem cells in regenerative medicine is well known and defining or improving their isolation methods is therefore a primary and crucial step. In the present paper we present a novel method to isolate stem cells from human skin, including the involvement of a novel medium for the maintenance and expansion of in vitro cultures. The biopsies were mechanically digested and put in culture. The migrating cells were positive selected with magnetic cell sorting, characterized by flow-cytometry analysis, and viability detected by MTT assay. Cells exhibited a mesenchymal phenotype, as demonstrated by the positive acquirement of an osteogenic or adipogenic phenotype when cultured in specific conditioned media. Taken together our results disclose a novel method for culturing and expanding stem cells from skin and pave the way for future clinical applications in tissue regeneration.

Stem cells and physical energies: can we really drive stem cell fate?

Adult stem cells are undifferentiated elements able to self-renew or differentiate to maintain tissue integrity. Within this context, stem cells are able to divide in a symmetric fashion, feature characterising all the somatic cells, or in an asymmetric way, which leads daughter cells to different fates. It is worth highlighting that cell polarity have a critical role in regulating stem cell asymmetric division and the proper control of cell division depends on different proteins involved in cell development, differentiation and maintenance of tissue homeostasis. Moreover, the interaction between cells and the extracellular matrix are crucial in influencing cell behavior, included in terms of mechanical properties as cytoskeleton plasticity and remodelling, and membrane tension. Finally, the activation of specific transcriptional program and epigenetic modifications contributes to cell fate determination, through modulation of cellular signalling cascades. It is well known that physical and mechanical stimuli are able to influence biological systems, and in this context, the effects of electromagnetic fields (EMFs) have already shown a considerable role, even though there is a lack of knowledge and much remains to be done around this topic. In this review, we summarize the historical background of EMFs applications and the main molecular mechanism involved in cellular remodelling, with particular attention to cytoskeleton elasticity and cell polarity, required for driving stem cell behavior.

Behavioral Changes in Stem-Cell Potency by HepG2-Exhausted Medium

Wharton jelly mesenchymal stem cells (WJ-MSCs) are able to differentiate into different cell lineages upon stimulation. This ability is closely related to the perfect balance between the pluripotency-related genes, which control stem-cell proliferation, and genes able to orchestrate the appearance of a specific phenotype. Here we studied the expression of stemness-related genes, epigenetic regulators (DNMT1, SIRT1), miRNAs (miR-145, miR-148, and miR-185) related to stemness, exosomes, the cell-cycle regulators p21 (WAF1/CIP1) and p53, and the senescence-associated genes (p16, p19, and hTERT). Cells were cultured in the presence or absence of the human hepatocarcinoma cell line HepG2-exhausted medium, to evaluate changes in stemness, differentiation capability, and senescence sensibility. Our results showed the overexpression of SIRT1 and reduced levels of p21 mRNA. Moreover, we observed a downregulation of DNMT1, and a simultaneous overexpression of Oct-4 and c-Myc. These findings suggest that WJ-MSCs are more likely to retain a stem phenotype and sometimes to switch to a highly undifferentiable proliferative-like behavior if treated with medium exhausted by human HepG2 cell lines.

Fibroblast Proliferation and Migration in Wound Healing by Phytochemicals: Evidence for a Novel Synergic Outcome

Wound-healing is a dynamic skin reparative process that results in a sequence of events, including inflammation, proliferation, and migration of different cell types as fibroblasts. Fibroblasts play a crucial role in repairing processes, from the late inflammatory phase until the fully final epithelization of the injured tissue. Within this context, identifying tools able to implement cell proliferation and migration could improve tissue regeneration. Recently, plants species from all over the world are coming out as novel tools for therapeutic applications thanks to their phytochemicals, which have antioxidant properties and can promote wound healing. In this paper, we aimed at investigating antioxidant activity of waste extracts from different medicinal plants, endemic of the Mediterranean area, on fibroblast proliferation and wound healing. We determined the amount of total phenols and anti-oxidant activity by ABTS assay. We then evaluated the cytotoxicity of the compounds and the proliferative capabilities of fibroblasts by scratch assay. Our results showed that waste extracts retain antioxidant and regenerative properties, inducing tissue re-establishment after environmental stress exposure. Taken together, our findings suggest that waste material could be used in the future also in combinations to stimulate wound healing processes and antioxidant responses in damaged skin.

Thyroid Hormone Diseases and Osteoporosis

Thyroid hormones are essential for normal skeletal development and normal bone metabolism in adults but can have detrimental effects on bone structures in states of thyroid dysfunction. Untreated severe hyperthyroidism influences the degree of bone mass and increases the probability of high bone turnover osteoporosis. Subclinical hyperthyroidism, defined as low thyrotropin (TSH) and free hormones within the reference range, is a subtler disease, often asymptomatic, and the diagnosis is incidentally made during screening exams. However, more recent data suggest that this clinical condition may affect bone metabolism resulting in decreased bone mineral density (BMD) and increased risk of fracture, particularly in postmenopausal women. The main causes of exogenous subclinical hyperthyroidism are inappropriate replacement dose of thyroxin and TSH suppressive L-thyroxine doses in the therapy of benign thyroid nodules and thyroid carcinoma. Available data similarly suggest that a long-term TSH suppressive dose of thyroxin may decrease BMD and may induce an increased risk of fracture. These effects are particularly observed in postmenopausal women but are less evident in premenopausal women. Overt hypothyroidism is known to lower bone turnover by reducing both osteoclastic bone resorption and osteoblastic activity. These changes in bone metabolism would result in an increase in bone mineralization. At the moment, there are no clear data that demonstrate any relationship between BMD in adults and hypothyroidism. Despite these clinical evidences, the cellular and molecular actions of thyroid hormones on bone structures are not complete clear.

Unravelling Cellular Mechanisms of Stem Cell Senescence: An Aid from Natural Bioactive Molecules

Cellular senescence plays a role in the onset of age-related pathologies and in the loss of tissue homeostasis. Natural compounds of food or plants exert an important antioxidant activity, counteracting the formation of harmful free radicals. In the presence of an intense stressing event, cells activate specific responses to counteract senescence or cell death. In the present paper, we aimed at evaluating the levels of expression of specific markers of senescence, in order to demonstrate that extracts from Myrtus Communis L. can prevent premature senescence in ADSCs exposed to oxidative stress. Cells were cultured in the presence of Myrtus extracts for 12-24 and 48 h and then incubated with H₂O₂ to induce senescence. We then evaluated the expression of senescence-related markers p16, p19, p21, p53, TERT, c-Myc, and the senescence-associated β-Galactoidase activity. Our results showed that pre-treatment with Myrtus extracts protects cells from premature senescence, by regulating the cell cycle, and inducing the expression of TERT and c-Myc. These findings suggest a potential application of these natural compounds in the prevention and treatment of various diseases, counteracting premature senescence and preserving tissue functions.

Intracrine Endorphinergic Systems in Modulation of Myocardial Differentiation

A wide variety of peptides not only interact with the cell surface, but govern complex signaling from inside the cell. This has been referred to as an "intracrine" action, and the orchestrating molecules as "intracrines". Here, we review the intracrine action of dynorphin B, a bioactive end-product of the prodynorphin gene, on nuclear opioid receptors and nuclear protein kinase C signaling to stimulate the transcription of a gene program of cardiogenesis. The ability of intracrine dynorphin B to prime the transcription of its own coding gene in isolated nuclei is discussed as a feed-forward loop of gene expression amplification and synchronization. We describe the role of hyaluronan mixed esters of butyric and retinoic acids as synthetic intracrines, controlling prodynorphin gene expression, cardiogenesis, and cardiac repair. We also discuss the increase in prodynorphin gene transcription and intracellular dynorphin B afforded by electromagnetic fields in stem cells, as a mechanism of cardiogenic signaling and enhancement in the yield of stem cell-derived cardiomyocytes. We underline the possibility of using the diffusive features of physical energies to modulate intracrinergic systems without the needs of viral vector-mediated gene transfer technologies, and prompt the exploration of this hypothesis in the near future.

Epigenetics, Stem Cells, and Autophagy: Exploring a Path Involving miRNA

MiRNAs, a small family of non-coding RNA, are now emerging as regulators of stem cell pluripotency, differentiation, and autophagy, thus controlling stem cell behavior. Stem cells are undifferentiated elements capable to acquire specific phenotype under different kind of stimuli, being a main tool for regenerative medicine. Within this context, we have previously shown that stem cells isolated from Wharton jelly multipotent stem cells (WJ-MSCs) exhibit gender differences in the expression of the stemness related gene OCT4 and the epigenetic modulator gene DNA-Methyltransferase (DNMT1). Here, we further analyze this gender difference, evaluating adipogenic and osteogenic differentiation potential, autophagic process, and expression of miR-145, miR-148a, and miR-185 in WJ-MSCs derived from males and females. These miRNAs were selected since they are involved in OCT4 and DNMT1 gene expression, and in stem cell differentiation. Our results indicate a difference in the regulatory circuit involving miR-148a/DNMT1/OCT4 autophagy in male WJ-MSCs as compared to female cells. Moreover, no difference was detected in the expression of the two-differentiation regulating miRNA (miR-145 and miR-185). Taken together, our results highlight a different behavior of WJ-MSCs from males and females, disclosing the chance to better understand cellular processes as autophagy and stemness, usable for future clinical applications.

Angiotensin II and TGF-β1 Induce Alterations in Human Amniotic Fluid-Derived Mesenchymal Stem Cells Leading to Cardiomyogenic Differentiation Initiation

Background and Objectives

Human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) may be a valuable source for cardiovascular tissue engineering and cell therapy. The aim of this study is to verify angiotensin II and transforming growth factor-beta 1 (TGF-β1) as potential cardiomyogenic differentiation inducers of AF-MSCs.

Methods and Results

AF-MSCs were obtained from amniocentesis samples from second-trimester pregnant women, isolated and characterized by the expression of cell surface markers (CD44, CD90, CD105 positive; CD34 negative) and pluripotency genes (OCT4, SOX2, NANOG, REX1). Cardiomyogenic differentiation was induced using different concentrations of angiotensin II and TGF-β1. Successful initiation of differentiation was confirmed by alterations in cell morphology, upregulation of cardiac genes-markers NKX2-5, TBX5, GATA4, MYH6, TNNT2, DES and main cardiac ion channels genes (sodium, calcium, potassium) as determined by RT-qPCR. Western blot and immunofluorescence analysis revealed the increased expression of Connexin43, the main component of gap junctions, and Nkx2.5, the early cardiac transcription factor. Induced AF-MSCs switched their phenotype towards more energetic and started utilizing oxidative phosphorylation more than glycolysis for energy production as assessed using Agilent Seahorse XF analyzer. The immune analysis of chromatin-modifying enzymes DNMT1, HDAC1/2 and Polycomb repressive complex 1 and 2 (PRC1/2) proteins BMI1, EZH2 and SUZ12 as well as of modified histones H3 and H4 indicated global chromatin remodeling during the induced differentiation.

Conclusions

Angiotensin II and TGF-β1 are efficient cardiomyogenic inducers of human AF-MSCs; they initiate alterations at the gene and protein expression, metabolic and epigenetic levels in stem cells leading towards cardiomyocyte- like phenotype formation.

Extracts from Myrtle Liqueur Processing Waste Modulate Stem Cells Pluripotency under Stressing Conditions

Nutraceuticals present in food are molecules able to exert biological activity for the prevention and treatment of various diseases, in form of pharmaceutical preparations, such as capsules, cream, or pills. Myrtus communis L. is a spontaneous Mediterranean evergreen shrub, widely known for the liqueur obtained from its berries rich in phytochemicals such as tannins and flavonoids. In the present study, we aimed to evaluate the properties of myrtle byproducts, residual of the industrial liqueur processing, in Adipose-derived stem cells (ADSCs) induced at oxidative stress by in vitro H₂O₂ treatment. Cells were exposed for 12-24 and 48h at treatment with extracts and then senescence-induced. ROS production was then determined. The real-time PCR was performed to evaluate the expression of inflammatory cytokines and sirtuin-dependent epigenetic changes, as well the modifications in terms of stem cell pluripotency. The β-galactosidase assay was conducted to analyze stem cell senescence after treatment. Our results show that industrial myrtle byproducts retain a high antioxidant and antisenescence activity, protecting cells from oxidative stress damages. The results obtained suggest that residues from myrtle liqueur production could be used as resource in formulation of food supplements or pharmaceutical preparations with antioxidant, antiaging, and anti-inflammatory activity.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes diseases.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes diseases.

Magnesium Deprivation Potentiates Human Mesenchymal Stem Cell Transcriptional Remodeling

Magnesium plays a pivotal role in energy metabolism and in the control of cell growth. While magnesium deprivation clearly shapes the behavior of normal and neoplastic cells, little is known on the role of this element in cell differentiation. Here we show that magnesium deficiency increases the transcription of multipotency markers and tissue-specific transcription factors in human adipose-derived mesenchymal stem cells exposed to a mixture of natural molecules, i.e., hyaluronic, butyric and retinoid acids, which tunes differentiation. We also demonstrate that magnesium deficiency accelerates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. We argue that magnesium deprivation generates a stressful condition that modulates stem cell plasticity and differentiation potential. These studies indicate that it is possible to remodel transcription in mesenchymal stem cells by lowering extracellular magnesium without the need for genetic manipulation, thus offering new hints for regenerative medicine applications.

Cardiac Restoration Stemming From the Placenta Tree: Insights From Fetal and Perinatal Cell Biology

Efficient cardiac repair and ultimate regeneration still represents one of the main challenges of modern medicine. Indeed, cardiovascular disease can derive from independent conditions upsetting heart structure and performance: myocardial ischemia and infarction (MI), pharmacological cardiotoxicity, and congenital heart defects, just to name a few. All these disorders have profound consequences on cardiac tissue, inducing the onset of heart failure over time. Since the cure is currently represented by heart transplantation, which is extremely difficult due to the shortage of donors, much effort is being dedicated to developing innovative therapeutic strategies based on stem cell exploitation. Among the broad scenario of stem/progenitor cell subpopulations, fetal and perinatal sources, namely amniotic fluid and term placenta, have gained interest due to their peculiar regenerative capacity, high self-renewal capability, and ease of collection from clinical waste material. In this review, we will provide the state-of-the-art on fetal perinatal stem cells for cardiac repair and regeneration. We will discuss different pathological conditions and the main therapeutic strategies proposed, including cell transplantation, putative paracrine therapy, reprogramming, and tissue engineering approaches.

Synthesis of magnolol and honokiol derivatives and their effect against hepatocarcinoma cells

The hepatocellular carcinoma is one of the most common malignant tumour with high level of mortality rate due to its rapid progression and high resistance to conventional chemotherapies. Thus, the search for novel therapeutic leads is of global interest. Herein, a small set of derivatives of magnolol 1 and honokiol 2, the main components of Magnolia grandiflora and Magnolia obovata, were evaluated in in vitro assay using tumoral hepatocytes. The pro-drug approach was applied as versatile strategy to the improve bioactivity of the compounds by careful transformation of the hydroxyl groups of magnolol 1 and honokiol 2 in suitable ester derivatives. Compounds 10 and 11 resulted to be more potent than the parental honokiol 2 at concentration down to 1 μM with complete viability of treated fibroblast cells up to concentrations of 80 μM. The combination of a butyrate ester and a bare phenol-OH group in the honokiol structure seemed to play a significant role in the antiproliferative activity identifying an interesting pharmacological clue against hepatocellular carcinoma.

Melatonin and Vitamin D Orchestrate Adipose Derived Stem Cell Fate by Modulating Epigenetic Regulatory Genes

Melatonin, that regulates many physiological processes including circadian rhythms, is a molecule able to promote osteoblasts maturation in vitro and to prevent bone loss in vivo, while regulating also adipocytes metabolism. In this regard, we have previously shown that melatonin in combination with vitamin D, is able to counteract the appearance of an adipogenic phenotype in adipose derived stem cells (ADSCs), cultured in an adipogenic favoring condition. In the present study, we aimed at evaluating the specific phenotype elicited by melatonin and vitamin D based medium, considering also the involvement of epigenetic regulating genes. ADSCs were cultured in a specific adipogenic conditioned media, in the presence of melatonin alone or with vitamin D. The expression of specific osteogenic related genes was evaluated at different time points, together with the histone deacetylases epigenetic regulators, HDAC1 and Sirtuins (SIRT) 1 and 2. Our results show that melatonin and vitamin D are able to modulate ADSCs commitment towards osteogenic phenotype through the upregulation of HDAC1, SIRT 1 and 2, unfolding an epigenetic regulation in stem cell differentiation and opening novel strategies for future therapeutic balancing of stem cell fate toward adipogenic or osteogenic phenotype.

Amniotic fluid stem cell models: A tool for filling the gaps in knowledge for human genetic diseases

Induced pluripotent stem (iPS) cells have attracted attention in recent years as a model of human genetic diseases. Starting from the diseased somatic cells isolated from an affected patient, iPS cells can be created and subsequently differentiated into various cell types that can be used to gain a better understanding of the disease at a cellular and molecular level. There are limitations of iPS cell generation, however, due to low efficiency, high costs, and lengthy protocols. The use of amniotic fluid stem cells (AFS) presents a worthy alternative as a stem cell source for modeling of human genetic diseases. Prenatal identification of chromosomal or Mendelian diseases may require the collection of amniotic fluid which is not only useful for the sake of diagnosis but also from this, AFS cells can be isolated and cultured. Since AFS cells show some characteristics of pluripotency, having the capacity to differentiate into various cell types derived from all three germ layers in vitro, they are a well-suited model for investigations regarding alterations in the molecular biology of a cell due to a specific genetic disease. This readily accessible source of stem cells can replace the necessity for generating iPS cells. Here, we expand on the applicability and importance of AFS cells as a model for discovery in the field of human genetic disease research. This paper is a review article. Referred literature in this paper has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors’ experiences.

REAC technology and hyaluron synthase 2, an interesting network to slow down stem cell senescence

Hyaluronic acid (HA) plays a fundamental role in cell polarity and hydrodynamic processes, affording significant modulation of proliferation, migration, morphogenesis and senescence, with deep implication in the ability of stem cells to execute their differentiating plans. The Radio Electric Asymmetric Conveyer (REAC) technology is aimed to optimize the ions fluxes at the molecular level in order to optimize the molecular mechanisms driving cellular asymmetry and polarization. Here, we show that treatment with 4-methylumbelliferone (4-MU), a potent repressor of type 2 HA synthase and endogenous HA synthesis, dramatically antagonized the ability of REAC to recover the gene and protein expression of Bmi1, Oct4, Sox2, and Nanog in ADhMSCs that had been made senescent by prolonged culture up to the 30^th passage. In senescent ADhMSCs, 4-MU also counteracted the REAC ability to rescue the gene expression of TERT, and the associated resumption of telomerase activity. Hence, the anti-senescence action of REAC is largely dependent upon the availability of endogenous HA synthesis. Endogenous HA and HA-binding proteins with REAC technology create an interesting network that acts on the modulation of cell polarity and intracellular environment. This suggests that REAC technology is effective on an intracellular niche level of stem cell regulation.

The transplantation of Akt-overexpressing amniotic fluid-derived mesenchymal stem cells protects the heart against ischemia-reperfusion injury in rabbits

Amniotic fluid-derived mesenchymal stem cells (AFMSCs) are an attractive cell source for applications in regenerative medicine, due to characteristics such as proliferative capacity and multipotency. In addition, Akt, a serine‑threonine kinase, maintains stem cells by promoting viability and proliferation. Whether the transplantation of Akt-overexpressing AFMSCs protects the heart against ischemia‑reperfusion (I/R) injury has yet to be elucidated. Accordingly, the Akt gene was overexpressed in AFMSCs using lentiviral transduction, and Akt‑AFMSCs were transplanted into the ischemic myocardium of rabbits prior to reperfusion. Any protective effects resulting from this procedure were subsequently sought after three weeks later. A histological examination revealed that there was a decrease in intramyocardial inflammation and ultrastructural damage, and an increase in capillary density and in the levels of GATA binding protein 4, connexin 43 and cardiac troponin T in the Akt‑AFMSC group compared with the control group. A significant decrease in cardiomyocyte apoptosis, accompanying an increase in phosphorylated Akt and B‑cell lymphoma 2 (Bcl-2) and a decrease in caspase‑3, was also observed. Furthermore, the left ventricular function was markedly augmented in the Akt‑AFMSC group compared with the control group. These observations suggested that the protective effect of AFMSCs may be due to the delivery of secreted cytokines, promotion of neoangiogenesis, prevention of cardiomyocyte apoptosis, transdifferentiation into cardiomyocytes and promotion of the viability of AFMSCs, which are assisted by Akt gene modification. Taken together, the results of the present study have indicated that transplantation of Akt-AFMSCs is able to alleviate myocardial I/R injury and improve cardiac function.

Amniotic Fluid Stem Cells: A Novel Source for Modeling of Human Genetic Diseases

In recent years, great interest has been devoted to the use of Induced Pluripotent Stem cells (iPS) for modeling of human genetic diseases, due to the possibility of reprogramming somatic cells of affected patients into pluripotent cells, enabling differentiation into several cell types, and allowing investigations into the molecular mechanisms of the disease. However, the protocol of iPS generation still suffers from technical limitations, showing low efficiency, being expensive and time consuming. Amniotic Fluid Stem cells (AFS) represent a potential alternative novel source of stem cells for modeling of human genetic diseases. In fact, by means of prenatal diagnosis, a number of fetuses affected by chromosomal or Mendelian diseases can be identified, and the amniotic fluid collected for genetic testing can be used, after diagnosis, for the isolation, culture and differentiation of AFS cells. This can provide a useful stem cell model for the investigation of the molecular basis of the diagnosed disease without the necessity of producing iPS, since AFS cells show some features of pluripotency and are able to differentiate in cells derived from all three germ layers “in vitro”. In this article, we describe the potential benefits provided by using AFS cells in the modeling of human genetic diseases.

Osteogenesis from Dental Pulp Derived Stem Cells: A Novel Conditioned Medium Including Melatonin within a Mixture of Hyaluronic, Butyric, and Retinoic Acids

Human dental pulp stem cells (hDPSCs) have shown relevant potential for cell therapy in the orthopedic and odontoiatric fields. The optimization of their osteogenic potential is currently a major challenge. Vascular endothelial growth factor A (VEGF A) has been recently reported to act as a major conductor of osteogenesis in vitro and in vivo. Here, we attempted to prime endogenous VEGF A expression without the need for viral vector mediated gene transfer technologies. We show that hDPSCs exposure to a mixture of hyaluronic, butyric, and retinoic acids (HA + BU + RA) induced the transcription of a gene program of osteogenesis and the acquirement of an osteogenic lineage. Such response was also elicited by cell exposure to melatonin, a pleiotropic agent that recently emerged as a remarkable osteogenic inducer. Interestingly, the commitment to the osteogenic fate was synergistically enhanced by the combinatorial exposure to a conditioned medium containing both melatonin and HA + BU + RA. These in vitro results suggest that in vivo osteogenesis might be improved and further studies are needed.