Role of mesenchymal stem cells in cell life and their signaling

Synthesis and Systematic Investigation of Lepidiline A and Its Gold(I), Silver(I), and Copper(I) Complexes Using In Vitro Cancer Models and Multipotent Stem Cells

The imidazole alkaloid lepidiline A from the root of Lepidium meyenii has a moderate to low in vitro anticancer effect. Our aim was to extend cytotoxicity investigations against a panel of cancer cells, including multidrug-resistant cancer cells, and multipotent stem cells. Lepidiline A is a N-heterocyclic carbene precursor, therefore a suitable ligand source for metal complexes. Thus, we synthesized lepidiline A and its copper(I), gold(I), and silver(I) complexes and tested them against ovarian, gastrointestinal, breast, and uterine cancer cells and bone marrow-derived and adipose-derived mesenchymal stem cells. Lepidiline A and its copper complex demonstrated moderate cytotoxicity, while silver and gold complexes exhibited significantly enhanced and consistent cytotoxicity against both cancer and stem cell lines. ABCB1 in the multidrug-resistant uterine sarcoma line conferred significant resistance against lepidiline A and the copper-lepidiline A complex, but not against the silver and gold complexes. Our results indicate that only the copper complex induced a significant and universal increase in the production of reactive oxygen species within cells. In summary, binding of metal ions to lepidiline A results in enhanced cytotoxicity with the nature of the metal ion playing a critical role in determining its properties.

Biomaterial-mediated presentation of wnt5a mimetic ligands enhances chondrogenesis and metabolism of stem cells by activating non-canonical Wnt signaling

The presentation of development-relevant bioactive cues by biomaterial scaffolds is essential to the guided differentiation of seeded human mesenchymal stem cells (hMSCs) and subsequent tissue regeneration. Wnt5a is a critical non-canonical Wnt signaling ligand and plays a key role in the development of musculoskeletal tissues including cartilage. Herein we investigate the efficacy of biofunctionalizing the hyaluronic acid hydrogel with a synthetic Wnt5a mimetic ligand (Foxy5 peptide) to promote the chondrogenesis of hMSCs and the potential underlying molecular mechanism. Our findings show that the conjugation of Foxy5 peptide in the hydrogels activates non-canonical Wnt signaling of encapsulated hMSCs via the upregulation expression of PLCE1, CaMKII-β, and downstream NFATc1, leading to enhanced expression of chondrogenic markers such as SOX9. The decoration of Foxy5 peptide also promotes the metabolic activities of encapsulated hMSCs as evidenced by upregulated gene expression of mitochondrial complex components and glucose metabolism biomarkers, leading to enhanced ATP biosynthesis. Furthermore, the conjugation of Foxy5 peptide activates the non-canonical Wnt, PI3K-PDK-AKT and IKK/NF-κB signaling pathways, thereby inhibiting the hypertrophy of the chondrogenically induced hMSCs in the hydrogels under both in vitro and in vivo conditions. This enhanced chondrogenesis and attenuated hypertrophy of hMSCs by the biomaterial-mediated bioactive cue presentation facilitates the potential clinical translation of hMSCs for cartilage regeneration. Our work provides valuable guidance to the rational design of bio-inductive scaffolds for various applications in regenerative medicine.

What Molecular Recognition Systems Do Mesenchymal Stem Cells/Medicinal Signaling Cells (MSC) Use to Facilitate Cell-Cell and Cell Matrix Interactions? A Review of Evidence and Options

Mesenchymal stem cells, also called medicinal signaling cells (MSC), have been studied regarding their potential to facilitate tissue repair for >30 years. Such cells, derived from multiple tissues and species, are capable of differentiation to a number of lineages (chondrocytes, adipocytes, bone cells). However, MSC are believed to be quite heterogeneous with regard to several characteristics, and the large number of studies performed thus far have met with limited or restricted success. Thus, there is more to understand about these cells, including the molecular recognition systems that are used by these cells to perform their functions, to enhance the realization of their potential to effect tissue repair. This perspective article reviews what is known regarding the recognition systems available to MSC, the possible systems that could be looked for, and alternatives to enhance their localization to specific injury sites and increase their subsequent facilitation of tissue repair. MSC are reported to express recognition molecules of the integrin family. However, there are a number of other recognition molecules that also could be involved such as lectins, inducible lectins, or even a MSC-specific family of molecules unique to these cells. Finally, it may be possible to engineer expression of recognition molecules on the surface of MSC to enhance their function in vivo artificially. Thus, improved understanding of recognition molecules on MSC could further their success in fostering tissue repair.

In vitro Assessment of the DNA Damage Response in Dental Mesenchymal Stromal Cells Following Low Dose X-ray Exposure

Stem cells contained within the dental mesenchymal stromal cell (MSC) population are crucial for tissue homeostasis. Assuring their genomic stability is therefore essential. Exposure of stem cells to ionizing radiation (IR) is potentially detrimental for normal tissue homeostasis. Although it has been established that exposure to high doses of ionizing radiation (IR) has severe adverse effects on MSCs, knowledge about the impact of low doses of IR is lacking. Here we investigated the effect of low doses of X-irradiation with medical imaging beam settings (<0.1 Gray; 900 mGray per hour), in vitro, on pediatric dental mesenchymal stromal cells containing dental pulp stem cells from deciduous teeth, dental follicle progenitor cells and stem cells from the apical papilla. DNA double strand break (DSB) formation and repair kinetics were monitored by immunocytochemistry of γH2AX and 53BP1 as well as cell cycle progression by flow cytometry and cellular senescence by senescence-associated β-galactosidase assay and ELISA. Increased DNA DSB repair foci, after exposure to low doses of X-rays, were measured as early as 30 min post-irradiation. The number of DSBs returned to baseline levels 24 h after irradiation. Cell cycle analysis revealed marginal effects of IR on cell cycle progression, although a slight G₂/M phase arrest was seen in dental pulp stromal cells from deciduous teeth 72 h after irradiation. Despite this cell cycle arrest, no radiation-induced senescence was observed. In conclusion, low X-ray IR doses (< 0.1 Gray; 900 mGray per hour), were able to induce significant increases in the number of DNA DSBs repair foci, but cell cycle progression seems to be minimally affected. This highlights the need for more detailed and extensive studies on the effects of exposure to low IR doses on different mesenchymal stromal cells.

Prevention of multiple system atrophy using human bone marrow-derived mesenchymal stem cells by reducing polyamine and cholesterol-induced neural damages

Background

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology, but is closely associated with damage to dopaminergic neurons. MSA progression is rapid. Hence, long-term drug treatments do not have any therapeutic benefits. We assessed the inhibitory effect of mesenchymal stem cells (MSCs) on double-toxin-induced dopaminergic neurodegenerative MSA.

Results

Behavioral disorder was significantly improved and neurodegeneration was prevented following MSC transplantation. Proteomics revealed lower expression of polyamine modulating factor-binding protein 1 (PMFBP1) and higher expression of 3-hydroxymethyl-3-methylglutaryl-CoA lyase (HMGCL), but these changes were reversed after MSC transplantation. In the in vitro study, the 6-OHDA-induced effects were reversed following co-culture with MSC. However, PMFBP1 knockdown inhibited the recovery effect due to the MSCs. Furthermore, HMGCL expression was decreased following co-culture with MSCs, but treatment with recombinant HMGCL protein inhibited the recovery effects due to MSCs.

Conclusions

These data indicate that MSCs protected against neuronal loss in MSA by reducing polyamine- and cholesterol-induced neural damage.

Medicinal Signaling Cells Metabolite Oral Based as a Potential Biocompatible Biomaterial Accelerating Oral Ulcer Healing (In Vitro Study)

OBJECTIVE

 Medicinal signaling cells metabolite (MSCM) is often considered medical waste even though it contains abundant growth factors, and advantageous micro- and macromolecules that can accelerate healing in oral ulcer.The purpose of this experimental laboratory study was to analyze the biocompatibility and potential of MSCM, (oral based) to accelerate healing in oral ulcer (in vitro).

MATERIALS AND METHODS

 MSCM (oral based) was obtained by mixing 10 mL of MSCM and 2% of carboxymethyl cellulose sodium. 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (or MTT assay) was obtained using human gingival somatic cell culture to examine cell viability treated with MSCM (oral based). Fourier transform infrared spectroscopy was performed to know the functional structure and composition of MSCM (oral based). To know the elemental composition of MSCM (oral based), energy-dispersive X-ray analysis was performed. Scratch test was performed to know the ability of MSCM (oral based) to increase human somatic cell proliferation.

RESULTS

 MSCM (oral based) has good cell viability. MSCM (oral based) administration accelerated the proliferation of human somatic cell culture after 12-hours in vitro. MSCM (oral based) has carboxylic acids and derivatives chemical bond. MSCM (oral based) mostly contained carbon and potassium but did not contain heavy metal substances.

CONCLUSIONS

 MSCM (oral based) has a biocompatible and potential ability to accelerate healing in oral ulcer in vitro. It would be useful in daily clinical practice in treating traumatic oral ulcer.

Self-assembled nanofiber coatings for controlling cell responses

Nanofibers are thought to enhance cell adhesion, growth, and function. We demonstrate that the choice of building blocks in self-assembling nanofiber systems can be used to control cell behavior. The use of 2 D-coated, self-assembled nanofibers in controlling lens epithelial cells, fibroblasts, and mesenchymal stem cells was investigated, focusing on gene and protein expression related to the fibrotic response. To this end, three nanofibers with different characteristics (morphology, topography, and wettability) were compared with two standard materials frequently used in culturing cells, TCPS, and a collagen type I coating. Cell metabolic activity, cell morphology, and gene and protein expression were analyzed. The most hydrophilic nanofiber with more compact network consisting of small fibers proved to provide a beneficial 2 D environment for cell proliferation and matrix formation while decreasing the fibrotic/stress behavior in all cell lines when compared with TCPS and the collagen type I coating. This nanofiber demonstrates the potential to be used as a biomimetic coating to study the development of fibrosis through epithelial-to-mesenchymal transition. This study also shows that nanofiber structures do not enhance cell function by definition, because the physico-chemical characteristics of the nanofibers influence cell behavior as well and actually can be used to regulate cell behavior toward suboptimal performance. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2252-2265, 2017.

The Complexity of Targeting PI3K-Akt-mTOR Signalling in Human Acute Myeloid Leukaemia: The Importance of Leukemic Cell Heterogeneity, Neighbouring Mesenchymal Stem Cells and Immunocompetent Cells

Therapeutic targeting of PI3K-Akt-mTOR is considered a possible strategy in human acute myeloid leukaemia (AML); the most important rationale being the proapoptotic and antiproliferative effects of direct PI3K/mTOR inhibition observed in experimental studies of human AML cells. However, AML is a heterogeneous disease and these effects caused by direct pathway inhibition in the leukemic cells are observed only for a subset of patients. Furthermore, the final effect of PI3K-Akt-mTOR inhibition is modulated by indirect effects, i.e., treatment effects on AML-supporting non-leukemic bone marrow cells. In this article we focus on the effects of this treatment on mesenchymal stem cells (MSCs) and monocytes/macrophages; both these cell types are parts of the haematopoietic stem cell niches in the bone marrow. MSCs have unique membrane molecule and constitutive cytokine release profiles, and mediate their support through bidirectional crosstalk involving both cell-cell contact and the local cytokine network. It is not known how various forms of PI3K-Akt-mTOR targeting alter the molecular mechanisms of this crosstalk. The effect on monocytes/macrophages is also difficult to predict and depends on the targeted molecule. Thus, further development of PI3K-Akt-mTOR targeting into a clinical strategy requires detailed molecular studies in well-characterized experimental models combined with careful clinical studies, to identify patient subsets that are likely to respond to this treatment.

Osteogenic Potential of Human Oral-Periosteal Cells (PCs) Isolated From Different Oral Origin: An In Vitro Study

The periosteum is a specialized connective tissue containing multipotent stem cells capable of bone formation. In this study, we aimed at demonstrating that human oral periosteal cells derived from three different oral sites (upper vestibule, lower vestibule, and hard palate) represent an innovative cell source for maxillo-facial tissue engineering applications in terms of accessibility and self-commitment towards osteogenic lineage. Periosteal cells (PCs) were isolated from patients with different ages (20-30 yy, 40-50 yy, 50-60 yy); we then analyzed the in vitro proliferation capacity and the bone self-commitment of cell clones culturing them without any osteogenic supplement to support their differentiation. We found that oral PCs, independently of their origin and age of patients, are mesenchymal stem cells with stem cell characteristics (clonogenical and proliferative activity) and that, even in absence of any osteogenic induction, they undertake the osteoblast lineage after 45 days of culture. These results suggest that oral periosteal cells could replace mesenchymal cells from bone marrow in oral tissue-engineering applications.

Anti-CD73 in cancer immunotherapy: awakening new opportunities

In recent years, cancer immunotherapy made significant advances due to a better understanding of the principles underlying tumor biology and immunology. In this context, CD73 is a key molecule, since via degradation of adenosine monophosphate into adenosine, endorses the generation of an immunosuppressed and pro-angiogenic niche within the tumor microenvironment that promotes the onset and progression of cancer. Targeting CD73 results in favorable antitumor effects in pre-clinical models and combined treatments of CD73 blockade with other immune-modulating agents (i.e. anti-CTLA-4 mAb or anti-PD1 mAb) is particularly attractive. Although there is still a long way to go, anti-CD73 therapy, through the development of CD73 monoclonal antibodies, can potentially constitute a new biologic therapy for cancer patients. In this review, we discuss the link between CD73 and the onset, development and spread of tumors, highlighting the potential value of this molecule as a target and as a novel biomarker in the context of personalized cancer therapy.

The conditioned medium from osteo-differentiating human mesenchymal stem cells affects the viability of triple negative MDA-MB231 breast cancer cells

This study aimed to investigate the effect of conditioned media (CM) from osteo-differentiating and adipo-differentiating human mesenchymal stem cells (MSCs) isolated from lipoaspirates of healthy female donors on the viability of triple-negative breast cancer cells MDA-MB231. The CM of undifferentiated and differentiating MSCs were collected after 7, 14, 21 and 28 days of culture. The effects of MSC CM on cell proliferation were assessed using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after 24 h. The effects of osteo-differentiating cell CM on apoptotic promotion, cell cycle impairment, mitochondrial transmembrane potential dissipation, production of reactive oxygen species and autophagosome accumulation were analysed by flow cytometry and Western blot. MTT assay showed that only CM collected from osteo-induced cells at day 28 (d28O-CM) reduced tumour cell viability. Treatment with d28O-CM restrained cell cycle progression through G2 phase, elicited a caspase-8-driven apoptotic effect already after 5 h of culture, and down-regulated autophagosome accumulation and beclin-1 expression. The finding that factor(s) secreted by osteo-differentiating MSCs shows properties of an apoptotic inducer and autophagy inhibitor on triple-negative breast cancer cells may have an important applicative potential that deserves further investigation.

MicroRNA-29a inhibits mesenchymal stem cell viability and proliferation by targeting Roundabout 1

Secreted Slit glycoproteins and their Roundabout (Robo) receptors have been identified as important axon guidance molecules. The pivotal role of Slit‑Robo signaling is in regulating cell proliferation. MicroRNAs (miRNAs), a class of small non‑coding RNAs, function as critical regulators of gene expression by binding to the 3'‑untranslated region of mRNAs and causing mRNA degradation or translational repression. The present study demonstrated that downregulation of Robo1 using small interfering RNA inhibited mesenchymal stem cell (MSC) proliferation. Additionally, four miRNAs (miR), including miR‑218, miR‑29a, miR‑146 and miR‑148, inhibited the protein expression of Robo1 in the MSCs, with miR‑29 having the most marked effect. A luciferase reporter assay identified Robo1 as a novel target of miR‑29a. Overexpression of miR‑29a suppressed the protein expression levels of Robo1 and Slit2 and inhibited the viability and proliferation of the MSCs. By contrast, overexpression of Robo1 partly rescued these inhibitory effects of miR‑29a on the MSCs confirming that miR‑29a inhibited MSC viability and proliferation, at least partially, by directly targeting Robo1. These results indicated that the miR‑29a/Robo1 axis is crucial for the regulation of MSC viability and proliferation, suggesting that miR‑29a may serve as a potential clinical target for MSC expansion and stem cell transplantation.

Origin of cells and network information

All cells are derived from one cell, and the origin of different cell types is a subject of curiosity. Cells construct life through appropriately timed networks at each stage of development. Communication among cells and intracellular signaling are essential for cell differentiation and for life processes. Cellular molecular networks establish cell diversity and life. The investigation of the regulation of each gene in the genome within the cellular network is therefore of interest. Stem cells produce various cells that are suitable for specific purposes. The dynamics of the information in the cellular network changes as the status of cells is altered. The components of each cell are subject to investigation.