Differentiation of rat adipose tissue-derived stem cells into neuron-like cells by valproic acid, a histone deacetylase inhibitor

Protein S-nitrosylation is involved in valproic acid-promoted neuronal differentiation of adipose tissue-derived stem cells

Neuronal differentiation of adipose tissue-derived stem cells (ASCs) is greatly promoted by valproic acid (VPA) with cAMP elevating agents thorough NO signaling pathways, but its mechanism is not fully understood. In the present study, we investigate the involvement of protein S-nitrosylation in the VPA-promoted neuronal differentiation of ASCs. The whole amount of S-nitrosylated protein was increased by the treatment with VPA alone for three days in ASCs. An inhibitor of thioredoxin reductase (TrxR), auranofin, further increased the amount of S-nitrosylated protein and enhances the VPA-promoted neuronal differentiation in ASCs. On the contrary, another inhibitor of TrxR, dinitrochlorobenzene, inhibited the VPA-promoted neuronal differentiation in ASCs even with cAMP elevating agents, which was accompanied by unexpectedly decreased S-nitrosylated protein. It was considered from these results that increased protein S-nitrosylation is involved in VPA-promoted neuronal differentiation of ASCs. By the proteomic analysis of S-nitrosylated protein in VPA-treated ASCs, no identified proteins could be specifically related to VPA-promoted neuronal differentiation. The identified proteins, however, included those involved in the metabolism of substances regulating neuronal differentiation, such as aspartate and glutamate.

Epigenetic regulation of dental-derived stem cells and their application in pulp and periodontal regeneration

Dental-derived stem cells have excellent proliferation ability and multi-directional differentiation potential, making them an important research target in tissue engineering. An increasing number of dental-derived stem cells have been discovered recently, including dental pulp stem cells (DPSCs), stem cells from exfoliated deciduous teeth (SHEDs), stem cells from apical papilla (SCAPs), dental follicle precursor cells (DFPCs), and periodontal ligament stem cells (PDLSCs). These stem cells have significant application prospects in tissue regeneration because they are found in an abundance of sources, and they have good biocompatibility and are highly effective. The biological functions of dental-derived stem cells are regulated in many ways. Epigenetic regulation means changing the expression level and function of a gene without changing its sequence. Epigenetic regulation is involved in many biological processes, such as embryonic development, bone homeostasis, and the fate of stem cells. Existing studies have shown that dental-derived stem cells are also regulated by epigenetic modifications. Pulp and periodontal regeneration refers to the practice of replacing damaged pulp and periodontal tissue and restoring the tissue structure and function under normal physiological conditions. This treatment has better therapeutic effects than traditional treatments. This article reviews the recent research on the mechanism of epigenetic regulation of dental-derived stem cells, and the core issues surrounding the practical application and future use of pulp and periodontal regeneration.

SFRP4+IGFBP5hi NKT cells induced neural-like cell differentiation to contribute to adenomyosis pain

Background

Adenomyosis is an estrogen-dependent gynecological disease. The pathogenesis of chronic pain, the main clinical symptom of adenomyosis, remains undefined. As a combination lymphocyte with both T-cell and natural killer (NK)-cell properties, NK T (NKT) cells play a role in immune defense against numerous diseases and modulate cell differentiation.

Method

This study analyzed the tissue-cell samples from adenomyosis with or without pain by single-cell sequencing.

Result

We found a specific population of secreted frizzled-related protein 4 (SFRP4)⁺NKT cells and a large amount of undifferentiated multipotent stem cells in the adenomyosis pain group. We discovered that a high expression of IGFBP5 in SFRP4⁺NKT cells could promote the differentiation of multipotent stem cells into neural-like cells via the single-cell trajectory. Through verification by the sample, we found that the degree of the expression of the neuronal marker NEFM was correlated with the duration of pain in adenomyosis patients. The expression of IGFBP5 was positively correlated with the pain scores of adenomyosis patients.

Conclusion

Collectively, these findings suggest that SFRP4⁺IGFBP5^hi NKT cells were capable of converting part of the stem cells into neurogenic cells and inducing adenomyosis pain.

Hydrogen sulfide potently promotes neuronal differentiation of adipose tissue-derived stem cells involving nitric oxide-mediated signaling cascade with the aid of cAMP-elevating agents

Neuronal differentiation of adipose tissue-derived stem cells (ASCs) is potently promoted by valproic acid (VPA) through a gaseous signaling molecule, nitric oxide (NO). Here, we investigated the involvement of hydrogen sulfide (H₂S), another gaseous signaling molecule, in neuronal differentiation of ASCs. VPA-promoted neuronal differentiation of ASCs was accompanied by increased intracellular H₂S and sulfane sulfur with increased mRNA expression of enzymes synthesizing sulfane sulfur including cystathionine β-synthase (CBS), of which inhibition reduced the differentiation efficiency. H₂S donors, GYY4137 (GYY) or NaHS, potently promoted neuronal differentiation of ASCs when cAMP-elevating agents, dibutyryl cyclic adenosine monophosphate and isobutyl methyl-xanthine, were added as neuronal induction medium (NIM). Neuronal differentiation of ASCs promoted by NaHS or GYY was accompanied by Ca²⁺ entry and increased mRNA expression of voltage-gated Ca²⁺ channels. NaHS or GYY also increased mRNA expression of enzymes of the NO-citrulline cycle including inducible NO synthase (iNOS). It was concluded from these results that H₂S potently promoted differentiation of ASCs into neuronal cells expressing functional voltage-gated Ca²⁺ channels with the aid of cAMP-elevating agents, involving NO-mediated signaling cascade. These effects of H₂S were also considered as a partial mechanism for the VPA-promoted neuronal differentiation of ASCs.

Valproic acid promotes differentiation of adipose tissue-derived stem cells to neuronal cells selectively expressing functional N-type voltage-gated Ca2+ channels

The differentiation of adipose tissue-derived stem cells (ASCs) to neuronal cells is greatly promoted by valproic acid (VPA), and is synergistically enhanced by the following treatment with neuronal induction medium (NIM) containing cAMP-elevating agents. In the present study, we investigated the synergism between VPA and NIM in neuronal differentiation of ASCs, assessed by the expression of neurofilament medium polypeptide (NeFM), with respect to Ca2+ entry. VPA (2 mM) treatment for 3 days followed by NIM for 2 h synergistically increased the incidence of neuronal cells differentiated from ASCs to an extent more than VPA alone treatment for 6 days, shortening the time required for the differentiation. VPA increased intracellular Ca2+ and the mRNAs of voltage-gated Ca2+ channels, Cacna1b (Cav2.2) and Cacna1h (Cav3.2), in ASCs. Inward currents through Ca2+ channels were evoked electrophysiologically at high voltage potential in ASCs treated with VPA. NIM reduced the mRNAs of NeFM and Cacna1b in VPA-promoted neuronal differentiation of ASCs. It was concluded that functional N-type voltage-gated Ca2+ channels (Cav2.2) are selectively expressed in VPA-promoted neuronal differentiation of ASCs. NIM seems to enhance the mRNA translation of molecules required for the differentiation. Neuronal cells obtained from ASCs by this protocol will be used as a cell source for regenerative therapy of neurological disorders associated with altered Cav2.2 activity.

Valproic acid up-regulates the whole NO-citrulline cycle for potent iNOS-NO signaling to promote neuronal differentiation of adipose tissue-derived stem cells

Valproic acid (VPA) remarkably promotes the differentiation of adipose tissue-derived stem cells (ASCs) to mature neuronal cells through nitric oxide (NO) signaling due to up-regulated inducible NO synthase (iNOS) as early as within 3 days. Here, we investigated mechanisms of VPA-promoted neuronal differentiation of ASCs concerning the NO-citrulline cycle, the metabolic cycle producing NO. Cultured rat ASCs were differentiated to mature neuronal cells rich in dendrites and expressing a neuronal marker by treatments with VPA at 2 mM for 3 days and subsequently with the neuronal induction medium for 2 h. Inhibitor (α-methyl-d, l-aspartic acid, MDLA) of arginosuccinate synthase (ASS), a key enzyme of the NO-citrulline cycle, abolishes intracellular NO increase and VPA-promoted neuronal differentiation in ASCs. l-Arginine, the substrate of iNOS, restores the promotion effect of VPA, being against MDLA. Immunocytochemistry showed that ASS and iNOS were increased in ASCs expressing neurofilament medium polypeptide (NeFM), a neuronal marker, by VPA and NIM synergistically. Real-time RT-PCR analysis showed that mRNAs of Ass and arginosuccinate lyase (Asl) in the NO-citrulline cycle were increased by VPA. Chromatin immunoprecipitation assay indicated that Ass and Asl were up-regulated by VPA through the acetylation of their associated histone. From these results, it was considered that VPA up-regulated the whole NO-citrulline cycle, which enabled continuous NO production by iNOS in large amounts for potent iNOS-NO signaling to promote neuronal differentiation of ASCs. This may also indicate a mechanism enabling short-lived NO to function conveniently as a potent signaling molecule that can disappear quickly after its role.

Dose optimization of early high-dose valproic acid for neuroprotection in a swine cardiac arrest model

Aim

High-dose valproic acid (VPA) improves the survival and neurologic outcomes after asphyxial cardiac arrest (CA) in rats. We characterized the pharmacokinetics, pharmacodynamics, and safety of high-dose VPA in a swine CA model to advance clinical translation.

Methods

After 8 ​min of untreated ventricular fibrillation CA, 20 male Yorkshire swine were resuscitated until return of spontaneous circulation (ROSC). They were block randomized to receive placebo, 75 ​mg/kg, 150 ​mg/kg, or 300 ​mg/kg VPA as 90-min intravenous infusion (n ​= ​5/group) beginning at ROSC. Animals were monitored for 2 additional hours then euthanized. Experimental operators were blinded to treatments.

Results

The mean(SD) total CA duration was 14.8(1.2) minutes. 300 ​mg/kg VPA animals required more adrenaline to maintain mean arterial pressure ≥80 ​mmHg and had worse lactic acidosis. There was a strong linear correlation between plasma free VPA C_max and brain total VPA (r² ​= ​0.9494; p ​< ​0.0001). VPA induced dose-dependent increases in pan- and site-specific histone H3 and H4 acetylation in the brain. Plasma free VPA C_max is a better predictor than peripheral blood mononuclear cell histone acetylation for brain H3 and H4 acetylation (r² ​= ​0.7189 for H3K27ac, r² ​= ​0.7189 for pan-H3ac, and r² ​= ​0.7554 for pan-H4ac; p ​< ​0.0001).

Conclusions

Up to 150 ​mg/kg VPA can be safely tolerated as 90-min intravenous infusion in a swine CA model. High-dose VPA induced dose-dependent increases in brain histone H3 and H4 acetylation, which can be predicted by plasma free VPA C_max as the pharmacodynamics biomarker for VPA target engagement after CA.

Homing of Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) Labeled Adipose-Derived Stem Cells by Magnetic Attraction in a Rat Model of Parkinson's Disease

Introduction

Stem cell therapies for neurodegenerative diseases such as Parkinson’s disease (PD) are intended to replace lost dopaminergic neurons. The basis of this treatment is to guide the migration of transplanted cells into the target tissue or injury site. The aim of this study is an evaluation of the homing of superparamagnetic iron oxide nanoparticles (SPIONs) labeled adipose-derived stem cells (ADSC) by an external magnetic field in a rat model of PD.

Methods

ADSCs were obtained from perinephric regions of male adult rats and cultured in a DMEM medium. ADSC markers were assessed by immunostaining with CD90, CD105, CD49d, and CD45. The SPION was coated using poly-L-lysine hydrobromide and transfection was determined in rat ADSC using the GFP reporter gene. For this in vivo study, rats with PD were divided into five groups: a positive control group, a control group with PD (lesion with 6-HD injection), and three treatment groups: the PD/ADSC group (PD transplant with ADSCs transfected by BrdU), PD/ADSC/SPION group (PD transplant with ADSCs labeled with SPION and transfected by GFP), and the PD/ADSC/SPION/EM group (PD transplant with ADSCs labeled with SPION and transfected by GFP induced with external magnet).

Results

ADSCs were immunoreactive to fat markers CD90 (90.73±1.7), CD105 (87.4±2.9) and CD49d (79.6±2.6), with negative immunostaining at the hematopoietic stem cell marker (CD45: 1.4±0.4). The efficiency of cells with SPION/PLL was about 96% of ADSC. The highest number of GFP-positive cells was in the ADSC/SPION/EM group (54.5±1.3), which was significantly different from that in ADSC/SPION group (30.83±3 and P<0.01).

Conclusion

Transfection of ADSC by SPION/PLL is an appropriate protocol for cell therapy. External magnets can be used for the delivery and homing of transplanted stem cells in the target tissue.

Adult stem cell response to doped bioactive borate glass

Bioactive glasses have transformed healthcare due to their versatility. Bioactive borate glass, in particular, has shown remarkable healing properties for both hard and soft tissues. Incorporating dopants into the composition of bioactive glass helps to control mechanical properties, and it increases their usefulness for clinical applications. Using a bioactive borate glass, 13-93B3 (B3), we investigated eleven dopants on the viability and migration potential of adipose stem cells (ASCs), a therapeutic source of cells used in tissue engineering and cell therapy. Our results show that under standard cell culture conditions, only Cu-doped B3 decreased cell viability, while only Y-doped B3 attracted ASCs as it dissolved in cell culture media. Using a transwell invasion assay, priming ASCs with Co, Fe, Ga, I, Sr, or Zn-doped B3 increased their homing capacity. Because there is widespread interest in optimizing and enhancing the homing efficiency of ASCs and other therapeutic cells, we then tested if priming bone marrow mesenchymal stem cells (BMSCs) with dopants also increased their homing capacity. In the case of BMSCs, there was a significant increase in invasion when cells were primed with any of the doped-B3 glasses. This work shows that incorporating dopants into borate glasses can provide a platform for a safe and efficient method that stimulates endogenous cells and healing mechanisms.

Valproic acid promotes mature neuronal differentiation of adipose tissue-derived stem cells through iNOS-NO-sGC signaling pathway

Valproic acid (VPA) remarkably promotes the differentiation of adipose tissue-derived stem cells (ASCs) to mature neuronal cells, enabling neuronal induction within only three days. Here, we investigated the involvement of NO-signaling in the VPA-promoted neuronal differentiation of ASCs as a possible mechanism. Cultured rat ASCs were differentiated to matured neuronal cells rich in dendrites and expressing βIII-tubulin protein, a neuronal marker, by treatments with VPA at 2 mM for 3 days and subsequently with the neuronal induction medium (NIM) containing cAMP-elevating agents for 2 h. Increased intracellular NO was detected in neuronal cells differentiated from ASCs treated with VPA by a fluorescence NO-specific probe, diaminofluorescein-FM diacetate. However, a NO donor (NOC18) increased the incidence of neuronal cells only to a lesser extent than VPA, indicating the insufficiency of exogenous NO. RT-PCR analysis of ASCs treated with VPA showed increased mRNA expression of inducible nitric oxide synthase (iNOS) with the acetylation of its associated histone H3K9. iNOS inhibitors (1400 W and dexamethasone) or a soluble guanylate cyclase (sGC) inhibitor (ODQ) decreased the incidence of neuronal cells differentiated from ASCs treated with VPA. These inhibitors also decreased the mRNA expression of mature neuronal markers, neurofilament medium polypeptide (NeFM) and microtubule-associated protein 2 (MAP2), as well as βIII-tubulin (TUBB3), to various extents. It was considered from these results that VPA promoted mature neuronal differentiation of ASCs through the iNOS-NO-sGC signaling pathway. This provided insights into the regulated neuronal differentiation of ASCs in clinical applications.

Immunocytochemical analysis of valproic acid induced histone H3 and H4 acetylation during differentiation of rat adipose derived stem cells into neuron-like cells

Valproic acid (VPA) is an inhibitor of histone deacetylases (HDACs) that can regulate differentiation and proliferation of stem cells by epigenetic mechanisms. We investigated VPA induced histone H3 and H4 acetylation in adipose derived stem cells (ADSCs) transdifferentiated into neuron-like cells (NLCs). Rat ADSCs were transdifferentiated into neural stem cells (NSCs) that had been generated from neurospheres. The NSCs were differentiated into NLCs by induction with different concentrations of VPA at 24, 48 and 72 h. The NLCs were evaluated using anti-H3 and -H4 antibodies, and ADSCs, NSCs and NLCs were evaluated using immunofluorescence. The ADSCs were immunoreactive to CD90 and CD49d, but not to CD45 and CD31. Both the neurospheres and NSCs were immunostained with nestin and neurofilament 68. The neurospheres expressed Musashi1, Sox2 and Neu N genes as determined by RT-PCR. Our dose-response study indicated that the optimal concentration of VPA was 1 mM at 72 h. Histone acetylation levels of H3 and H4 immunostaining intensities in NLCs were significantly greater than for ADSCs and NSCs. VPA alters H4 and H3 acetylation immunoreactivities of ADSCs transdifferentiated into NLCs.

Neurogenic differentiation of adipose derived stem cells on graphene-based mat

Adipose derived stem cells (ADSCs) have been proved as an abundant and accessible cell source with the ability to differentiate into neuron-like cells. However, the low differentiation efficiency puts forward an important challenge to practical applications in clinic. Considering of the good biocompatibility of graphene-based materials and the potential interaction between graphene and cells mentioned in previous studies, herein, we investigated the effect of graphene oxide (GO) and reduced graphene oxide (rGO) mats on neurogenic differentiation of the ADSCs. We demonstrated the excellent capabilities of graphene-based mats, especially GO to support the neural differentiation of ADSCs. By comparing the observation under an optical microscope and fluorescence microscope, the conversion rate of neuron-like cells reached about 90%. We consider that GO mat is better for promoting the differentiation of ADSCs into neuron-like cells, which compared to rGO based platforms. Meanwhile, we made an analysis of the mechanism by which graphene induced the differentiation of ADSCs to neuron-like cells. The data obtained here highlight the effect of GO mat on neurogenic differentiation of ADSCs and implicate the potential of graphene-based materials in application of neural tissue engineering for the limited self-repair capability of nerve cells.

Physiologically based microenvironment for in vitro neural differentiation of adipose-derived stem cells

The limited capacity of nervous system to promote a spontaneous regeneration and the high rate of neurodegenerative diseases appearance are keys factors that stimulate researches both for defining the molecular mechanisms of pathophysiology and for evaluating putative strategies to induce neural tissue regeneration. In this latter aspect, the application of stem cells seems to be a promising approach, even if the control of their differentiation and the maintaining of a safe state of proliferation should be troubled. Here, we focus on adipose tissue-derived stem cells and we seek out the recent advances on the promotion of their neural differentiation, performing a critical integration of the basic biology and physiology of adipose tissue-derived stem cells with the functional modifications that the biophysical, biomechanical and biochemical microenvironment induces to cell phenotype. The pre-clinical studies showed that the neural differentiation by cell stimulation with growth factors benefits from the integration with biomaterials and biophysical interaction like microgravity. All these elements have been reported as furnisher of microenvironments with desirable biological, physical and mechanical properties. A critical review of current knowledge is here proposed, underscoring that a real advance toward a stable, safe and controllable adipose stem cells clinical application will derive from a synergic multidisciplinary approach that involves material engineer, basic cell biology, cell and tissue physiology.

The effect of serum types on Chondrogenic differentiation of adipose-derived stem cells

Background

Fetal bovine serum (FBS) is the most essential supplement in culture media for cellular proliferation, metabolism, and differentiation. However, due to a limited supply and subsequently rising prices, a series of studies have investigated a biological feasibility of replaceable serums to substitute FBS. Along with the increasing interests to manufacture stem cell-based cellular products, optimizing the composition of culture media including serums and exogenous growth factors (GFs) is of importance. In this experiment, the effect of bovine serum (BS) and newborn calf serum (NCS) on proliferation and chondrogenic differentiation capacity of human adipose derived stem cells (ADSCs) was evaluated, especially in the chondrogenically supplemented culture condition.

Methods

ADSCs were chondrogenically cultured with FBS, BS, and NCS for 14 days. For the acceleration of in vitro chondrogenesis, exogenous insulin-like growth factor and transforming growth factor-β3 were added. Viability and proliferation of ADSCs were evaluated using Live/Dead fluorescence staining and DNA amount, respectively. To investigate a chondrogenic differentiation, a series of assays were performed including a quantification of glycosaminoglycan deposition, alcian blue staining, and RT-PCR analysis for type II collagen, aggrecan and Sox-9 genes.

Results

The results demonstrated that proliferation of ADSCs was facilitated in FBS condition as compared with other serum types. For chondrogenic marker gene expression, serum substitutes enhanced Sox-9 expression level on day 14. The deposition of glycosaminoglycan was more facilitated in BS condition regardless of additional chondrogenic GFs.

Conclusion

It could be presumably speculated that serum types and exogenous supplements of GFs could also be important parameters to optimize culture media composition, especially in order to maintain the enhanced levels of both proliferation and chondrogenic differentiation of ADSCs during expansion.

Effects of Valproic Acid on Morphology, Proliferation, and Differentiation of Mesenchymal Stem Cells Derived From Human Gingival Tissue

PURPOSE

Valproic acid (VPA), a histone deacetylase inhibitor, has been shown to affect cell growth and differentiation in various in vitro and in vivo models. The aim of this study is to evaluate the effects of VPA on viability and osteogenic differentiation of mesenchymal stem cells derived from the human gingival tissue.

MATERIALS AND METHODS

Stem cells derived from the gingiva were grown in the presence of VPA at concentrations ranging from 0.125 to 8 mM. Cell morphology was assessed on days 3, 5, and 7, and cell proliferation was analyzed on the same days using a Cell Counting Kit-8 (CCK-8). Alizarin Red-S staining was used to assess differentiation of the stem cells.

RESULTS

The control group showed a normal fibroblast morphology when cultured in growth media. The shape of cells in the 8 mM group was more flat than cells in other groups, and fewer cells were present. A statistically significant decrease in cell proliferation was seen in the 8 mM group. Results of Alizarin Red-S staining showed a significant decrease in mineralization in the 8 mM group.

CONCLUSIONS

Taken together, this study demonstrated that VPA, at the tested concentrations, decreases the viability of stem cells derived from the human gingiva. The decreases in osteogenic differentiation were achieved via the decrease of Rux2 expression. The concentration and application time of VPA treatment should be meticulously controlled to minimize any detrimental effects.