Comparison of standard surface chemistries for culturing mesenchymal stem cells prior to neural differentiation

Nanosheets Based Approach to Elevate the Proliferative and Differentiation Efficacy of Human Wharton's Jelly Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-based therapy and tissue repair necessitate the use of an ideal clinical biomaterial capable of increasing cell proliferation and differentiation. Recently, MXenes 2D nanomaterials have shown remarkable potential for improving the functional properties of MSCs. In the present study, we elucidated the potential of Ti2CTx MXene as a biomaterial through its primary biological response to human Wharton's Jelly MSCs (hWJ-MSCs). A Ti2CTx nanosheet was synthesized and thoroughly characterized using various microscopic and spectroscopic tools. Our findings suggest that Ti2CTx MXene nanosheet exposure does not alter the morphology of the hWJ-MSCs; however, it causes a dose-dependent (10-200 µg/mL) increase in cell proliferation, and upon using it with conditional media, it also enhanced its tri-lineage differentiation potential, which is a novel finding of our study. A two-fold increase in cell viability was also noticed at the highest tested dose of the nanosheet. The treated hWJ-MSCs showed no sign of cellular stress or toxicity. Taken together, these findings suggest that the Ti2CTx MXene nanosheet is capable of augmenting the proliferation and differentiation potential of the cells.

Comprehensive Evaluation of Stable Neuronal Cell Adhesion and Culture on One-Step Modified Polydimethylsiloxane Using Functionalized Pluronic

Polydimethylsiloxane (PDMS) is a popular and property-advantageous material for developing biomedical microsystems and advancing cell microengineering. The requirement of constructing a robust cell-adhesive PDMS interface drives the exploration of simple, straightforward, and applicable surface modification methods. Here, a comprehensive evaluation of highly stable neuronal cell adhesion and culture on the PDMS surface modified in one step using functionalized Pluronic is presented. According to multiple comparative tests, this modification is sufficiently verified to enable more significant cell adhesion and spreading in both quantity and stability, higher neuronal differentiation and viability/growth, more complete formation of the neuronal network, and stabler neuronal cell culture than the common coating tools on the PDMS substrate. The comparable and even superior cellular effects of this modification on PDMS to the standard coating of polystyrene for in vitro neurological research are demonstrated. Long-term microfluidic neuron culture with stable adhesion and high differentiation on the modified PDMS interface is accomplished, too. The achievement provides a detailed experimental demonstration of this simple and effective modification for strengthening neuronal cell culture on the PDMS substrate, which is useful for potential applications in the fields of neurobiology, neuron microengineering, and brain-on-a-chip.

Nanostructured TiC Layer is Highly Suitable Surface for Adhesion, Proliferation and Spreading of Cells

Cell culture is usually performed in 2D polymer surfaces; however, several studies are conducted with the aim to screen functional coating molecules to find substrates more suitable for cell adhesion and proliferation. The aim of this manuscript is to compare the cell adhesion and cytoskeleton organization of different cell types on different surfaces. Human primary fibroblasts, chondrocytes and osteoblasts isolated from patients undergoing surgery were seeded on polystyrene, poly-d-lysine-coated glass and titanium carbide slides and left to grow for several days. Then their cytoskeleton was analyzed, both by staining cells with phalloidin, which highlights actin fibers, and using Atomic Force Microscopy. We also monitored the production of Fibroblast Growth Factor-2, Bone Morphogenetic Protein-2 and Osteocalcin, using ELISA, and we highlighted production of Collagen type I in fibroblasts and osteoblasts and Collagen type II in chondrocytes by immunofluorescences. Fibroblasts, chondrocytes and osteoblasts showed both an improved proliferative activity and a good adhesion ability when cultured on titanium carbide slides, compared to polystyrene and poly-d-lysine-coated glass. In conclusion, we propose titanium carbide as a suitable surface to cultivate cells such as fibroblasts, chondrocytes and osteoblasts, allowing the preservation of their differentiated state and good adhesion properties.

IDH mutation and MGMT promoter methylation are associated with the pseudoprogression and improved prognosis of glioblastoma multiforme patients who have undergone concurrent and adjuvant temozolomide-based chemoradiotherapy

PURPOSE

This study aimed to investigate the potential association between IDH mutation and O⁶-methyl-guanine methyl transferase (MGMT) gene promoter methylation and pseudoprogression disease (psPD) in glioblastoma multiforme (GBM) patients after concurrent temozolomide (TMZ)-based chemoradiotherapy.

METHODS

A total of 157 GBM patients who received concurrent TMZ-based chemoradiotherapy were included in this retrospective study. The association between psPD and a number of demographic and genetic factors, including IDH mutation and MGMT promoter methylation, were analyzed based on logistic regression, Cox regression, and multivariate analysis.

RESULTS

Of the 157 GBM patients, 145 (92.36%) patients, including 38 patients with psPD, 38 patients with early progression (ePD), and 69 patients with non-progression (non-PD), were followed up for six to 56 months. We identified a higher rate of MGMT promoter methylation and IDH1 mutation in psPD patients compared with ePD patients (P=0.002). In addition, MGMT promoter methylation and IDH1 mutation predicted a high probability of psPD development in GBM patients (P=0.001 and P<0.001, respectively). MGMT promoter methylation, IDH1 mutation, Karnofsky performance score (KPS) ≥70, and psPD were associated with a significantly longer overall survival of GBM patients (P=0.001, 0.001, 0.002, and P<0.001, respectively). Both of MGMT promoter methylation and IDH mutation had a cumulative effect on the OS of GBM patients. GBM patients with psPD (39.2±2.1months, P<0.001) had a longer median survival (MS) than GBM patients with ePD (11.9±1.1months) or with non-PD (24.4±2.4months).

CONCLUSION

MGMT promoter methylation and IDH1 mutation were associated with PsPD and predicted a longer median survival in GBM patients after TMZ-based chemoradiotherapy. Genetic analyses of the MGMT promoter and IDH1 may allow us to effectively treat GBM patients.

An Overview of Protocols for the Neural Induction of Dental and Oral Stem Cells In Vitro

To date, various adult stem cells have been identified within the oral cavity, including dental pulp stem cells, dental follicle stem cells, stem cells from apical papilla, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, and mesenchymal stem cells from the gingiva. All of these possess neurogenic potential due to their common developmental origin from the embryonic neural crest. Besides the relative ease of isolation of these adult stem cells from readily available biological waste routinely produced during dental treatment, these cells also possess the advantage of immune compatibility in autologous transplantation. In recent years, much interest has been focused on the derivation of neural lineages from these adult stem cells for therapeutic applications in the brain, spinal cord, and peripheral nerve regeneration. In addition, there are also promising nontherapeutic applications of stem cell-derived neurons in pharmacological and toxicological screening of neuroactive drugs, and for in vitro modeling of neurodevelopmental and neurodegenerative diseases. Hence, this review will critically examine the diverse array of in vitro neural induction protocols that have been devised for dental and oral-derived stem cells. These protocols are defined not only by the culture milieu comprising the basal medium plus growth factors, small molecules, and other culture supplements but also by the substrata/surface coatings utilized, the presence of multiple culture stages, the total culture duration, the initial seeding density, and whether the spheroid/neurosphere formation is being utilized to recapitulate the three-dimensional neural differentiation microenvironment that is naturally present physiologically in vivo.

Poly-L-ornithine promotes preferred differentiation of neural stem/progenitor cells via ERK signalling pathway

Neural stem/progenitor cells (NSPCs) replacement therapies are the most attractive strategies to restore an injured brain. Key challenges of such therapies are enriching NSPCs and directing them differentiation into specific neural cell types. Here, three biomaterial substrates Poly-L-ornithine (PO), Poly-L-lysine (PLL) and fibronectin (FN) were investigated for their effects on proliferation and differentiation of rat NSPCs, and the underlying mechanisms were also explored. The results showed PO significantly increased NSPCs proliferation and induced preferred differentiation, compared with PLL and FN. Checking protein markers of several neural cell subtypes, it is showed PO significantly induced NSPCs expressing Doublecortin (DCX) and Olig2, one for neuroblasts and young neurons and the other for young oligodendrocytes. It is suggested the ERK signaling pathway was involving in this process because an ERK antagonist U0126 could inhibit PO’s effects mentioned above, as well as an ERK pathway agonist Ceramide C6 could enhance them. Given that both neurons and oligodendrocytes are the most vulnerable cells in many neurological diseases, PO-induced preferred differentiation into neurons and oligodendrocytes is a potential paradigm for NSPCs-based therapies.

Pendant small functional groups on poly(ϵ-caprolactone) substrate modulate adhesion, proliferation and differentiation of human mesenchymal stem cells

Probing stem cell-biomaterial interactions is of great significance in both gaining profound understanding of stem cell biology and advancing tissue regeneration. In the present work, we developed a series of poly(ϵ-caprolactone) (PCL) films bearing distinct pendant small functional groups to study the effects of biomaterial substrate chemistry on stem cell behaviors. PCL films, bearing hydroxyl (OH), methyl (CH₃), carboxyl (COOH) and amino (NH₂), demonstrated varied surface properties, such as wettability, serum protein adsorption and surface topographical feature. In comparison with pristine PCL film, the adhesion of hMSCs on PCL-COOH, PCL-OH and PCLCO films was significantly promoted and cells slightly outgrew on PCL-NH₂ and PCL-COOH films. Most importantly, the tri-lineage differentiation of hMSCs varied on this series of PCL films, with the best osteogenesis achieved on PCL-NH₂ film, PCL and PCL-CH₃ films supporting the superior adipogenic differentiation and PCL-CH₃ film being the most favorable one for chondrogenesis. This study highlights the critical roles of surface chemistry in modulating the fates of MSCs and potentially provides a practical guidance in developing instructive tissue engineering scaffolds.

Critical steps in the isolation and expansion of adipose-derived stem cells for translational therapy

Since the discovery of adipose-derived stem cells (ASCs), there have been high expectations of their putative clinical use. Recent advances support these expectations, and it is expected that the transition from pre-clinical and clinical studies to implementation as a standard treatment modality is imminent. However ASCs must be isolated and expanded according to good manufacturing practice guidelines and a basic assurance of quality, safety, and medical effectiveness is needed for authorisation by regulatory agencies, such as European Medicines Agency and US Food and Drug Administration. In this review, a collection of studies investigating the influence of different steps of the isolation and expansion protocol on the yield and functionality of ASCs has been presented in an attempt to come up with best recommendations that ensure potential beneficial clinical outcome of using ASCs in any therapeutic setting. If the findings confirm the initial observations of beneficial effects of ASCs, the path is paved for implementing these ASC-based therapies as standard treatment options.

Effects of mesenchymal stem cell therapy, in association with pharmacologically active microcarriers releasing VEGF, in an ischaemic stroke model in the rat

Few effective therapeutic interventions are available to limit brain damage and functional deficits after ischaemic stroke. Within this context, mesenchymal stem cell (MSC) therapy carries minimal risks while remaining efficacious through the secretion of trophic, protective, neurogenic and angiogenic factors. The limited survival rate of MSCs restricts their beneficial effects. The usefulness of a three-dimensional support, such as a pharmacologically active microcarrier (PAM), on the survival of MSCs during hypoxia has been shown in vitro, especially when the PAMs were loaded with vascular endothelial growth factor (VEGF). In the present study, the effect of MSCs attached to laminin-PAMs (LM-PAMs), releasing VEGF or not, was evaluated in vivo in a model of transient stroke. The parameters assessed were infarct volume, functional recovery and endogenous cellular reactions. LM-PAMs induced the expression of neuronal markers by MSCs both in vitro and in vivo. Moreover, the prolonged release of VEGF increased angiogenesis around the site of implantation of the LM-PAMs and facilitated the migration of immature neurons towards the ischaemic tissue. Nonetheless, MSCs/LM-PAMs-VEGF failed to improve sensorimotor functions. The use of LM-PAMs to convey MSCs and to deliver growth factors could be an effective strategy to repair the brain damage caused by a stroke.

Growth Properties and Pluripotency Marker Expression of Spontaneously Formed Three-dimensional Aggregates of Human Adipose-derived Stem Cells

Background and Objectives:

Recent findings suggest that therapeutic potential of mesenchymal stem cells (MSCs) could be increased through aggregation into three-dimensional (3D) bodies, and different culture methods have been employed to obtain 3D spheroids of MSCs. In the current study we report accidentally encountered spontaneous formation of adipose-derived stem cell (ASC) bodies in standard ASC culture of a single donor.

Methods and Results:

Human ASCs from passages 1 to 3, cultured in a medium containing 5% autologous serum (AS), spontaneously clustered and formed floating 3D bodies. After a transfer of floating ASC bodies onto new adherent plastic dish, they attached to the surface and gradual migration of spindle-shaped ASCs out of the bodies was detected. A substitution of AS with allogeneic sera did not hinder this ability, but commercial medium containing fetal bovine serum delayed the process. Substantial part of ASCs surrounding transferred ASC bodies showed alkaline phosphatase (AP) activity, while ASC aggregates were AP negative. Similar 3D bodies formed when ASCs were grown on an uncoated glass surface. These ASC aggregates as well as clusters of ASCs, where formation of the 3D bodies is initiated, expressed pluripotency marker NANOG, but the expression of OCT4A was not detected.

Conclusions:

Obtained results suggest that spontaneously formed ASC aggregates may represent a more primitive cell subpopulation within the individual ASC culture. The ability to form 3D aggregates, the expression of NANOG, and the lack of the AP activity may be used to enrich ASC cultures with potentially more primitive cells serving as an excellent basis for therapeutic applications.

Investigation of early cell-surface interactions of human mesenchymal stem cells on nanopatterned β-type titanium-niobium alloy surfaces

Multi-potent adult mesenchymal stem cells (MSCs) derived from bone marrow have therapeutic potential for bone diseases and regenerative medicine. However, an intrinsic heterogeneity in their phenotype, which in turn results in various differentiation potentials, makes it difficult to predict the response of these cells. The aim of this study is to investigate initial cell-surface interactions of human MSCs on modified titanium alloys. Gold nanoparticles deposited on β-type Ti-40Nb alloys by block copolymer micelle nanolithography served as nanotopographical cues as well as specific binding sites for the immobilization of thiolated peptides present in several extracellular matrix proteins. MSC heterogeneity persists on polished and nanopatterned Ti-40Nb samples. However, cell heterogeneity and donor variability decreased upon functionalization of the gold nanoparticles with cyclic RGD peptides. In particular, the number of large cells significantly decreased after 24 h owing to the arrangement of cell anchorage sites, rather than peptide specificity. However, the size and number of integrin-mediated adhesion clusters increased in the presence of the integrin-binding peptide (cRGDfK) compared with the control peptide (cRADfK). These results suggest that the use of integrin ligands in defined patterns could improve MSC-material interactions, not only by regulating cell adhesion locally, but also by reducing population heterogeneity.

Ambient DESI and LESA-MS analysis of proteins adsorbed to a biomaterial surface using in-situ surface tryptic digestion

The detection and identification of proteins adsorbed onto biomaterial surfaces under ambient conditions has significant experimental advantages but has proven to be difficult to achieve with conventional measuring technologies. In this study, we present an adaptation of desorption electrospray ionization (DESI) and liquid extraction surface analysis (LESA) mass spectrometry (MS) coupled with in-situ surface tryptic digestion to identify protein species from a biomaterial surface. Cytochrome c, myoglobin, and BSA in a combination of single and mixture spots were printed in an array format onto Permanox slides, followed by in-situ surface digestion and detection via MS. Automated tandem MS performed on surface peptides was able to identify the proteins via MASCOT. Limits of detection were determined for DESI-MS and a comparison of DESI and LESA-MS peptide spectra characteristics and sensitivity was made. DESI-MS images of the arrays were produced and analyzed with imaging multivariate analysis to automatically separate peptide peaks for each of the proteins within a mixture into distinct components. This is the first time that DESI and LESA-MS have been used for the in-situ detection of surface digested proteins on biomaterial surfaces and presents a promising proof of concept for the use of ambient MS in the rapid and automated analysis of surface proteins.

The effect of amino density on the attachment, migration, and differentiation of rat neural stem cells in vitro

Artificial extracellular matrices play important roles in the regulation of stem cell behavior. To generate materials for tissue engineering, active functional groups, such as amino, carboxyl, and hydroxyl, are often introduced to change the properties of the biomaterial surface. In this study, we chemically modified coverslips to create surfaces with different amino densities and investigated the adhesion, migration, and differentiation of neural stem cells (NSCs) under serum-free culture conditions. We observed that a higher amino density significantly promoted NSCs attachment, enhanced neuronal differentiation and promoted excitatory synapse formation in vitro. These results indicate that the amino density significantly affected the biological behavior of NSCs. Thus, the density and impact of functional groups in extracellular matrices should be considered in the research and development of materials for tissue engineering.

Influence of decellularized matrix derived from human mesenchymal stem cells on their proliferation, migration and multi-lineage differentiation potential

Developing biomaterials to promote stem cell proliferation and differentiation is a critical requirement in tissue engineering and regeneration. Extracellular matrix (ECM) derived from mesenchymal stem cells (MSCs) has recently been shown to be able to maintain the differentiation potential of MSCs during culture expansion and to restore the activities of aging MSCs, suggesting that MSC ECM (MECM) may be a suitable culture substrate to enhance the bioactivity of biomaterial scaffolds for MSCs. This investigation aims to characterize the biological nature and specificity of the influence of the MECM on MSCs. Native ECM produced by human MSC in vitro was extracted in urea, and the residual pellet was further processed with pepsin digestion (denoted as U-MECM and HP-MECM, respectively). The MECM products were then coated as a substrate on standard tissue culture plastic, and the behavior of MSCs seeded on the coated surfaces was studied. Our results showed that U-MECM coating dramatically accelerated MSC proliferation, attachment, spread, migration and multi-lineage differentiation (i.e., osteogenesis and adipogenesis), compared to collagen type I and HP-MECM coating. Non-collagenous proteins are likely the bioactive components in U-MECM, as MSCs cultured on collagen type I and HP-MECM showed similar biological activities, and collagen type I appeared to be the major protein components remaining in HP-MECM based on SDS-PAGE. These findings support the biological utility of MECM in the formulation of biomaterial scaffolds to enhance MSC bioactivities, including proliferation, migration and multi-lineage differentiation, for tissue regeneration applications.

Carbon nanotubes in neural interfacing applications

Carbon nanotubes (CNT) are remarkable materials with a simple and inert molecular structure that gives rise to a range of potentially valuable physical and electronic properties, including high aspect ratio, high mechanical strength and excellent electrical conductivity. This review summarizes recent research on the application of CNT-based materials to study and control cells of the nervous system. It includes the use of CNT as cell culture substrates, to create patterned surfaces and to study cell-matrix interactions. It also summarizes recent investigations of CNT toxicity, particularly as related to neural cells. The application of CNT-based materials to directing the differentiation of progenitor and stem cells toward neural lineages is also discussed. The emphasis is on how CNT surface chemistry and nanotopography can be altered, and how such changes can affect neural cell function. This knowledge can be applied to creating improved neural interfaces and devices, as well as providing new approaches to neural tissue engineering and regeneration.

Characterization of mesenchymal stem cells from rat bone marrow: ultrastructural properties, differentiation potential and immunophenotypic markers

Bone marrow-derived mesenchymal stem cells (BM-MSCs) can differentiate into many lineages. Although the growing interest in BM-MSCs has led to a number of characterization studies, some important biochemical and immunohistochemical properties are still lacking. In this study, morphological and immunophenotypic properties of BM-MSCs were examined in detail. Differentiation potential and growth kinetics of adult rat BM-MSCs were also determined. Immunohistochemistry and RT-PCR results indicated that BM-MSCs expressed myogenic (desmin, myogenin, myosin IIa, and alpha-SMA), neurogenic (gamma-enolase, MAP2a,b, c-fos, nestin, GFAP and beta III tubulin), and osteogenic (osteonectin, osteocalcin, osteopontin, Runx-2, BMP-2, BMP-4 and type I collagen) markers without stimulation towards differentiation. These expression patterns indicated why these cells can easily differentiate into multiple lineages both in vitro and in vivo. Ultrastructural characteristics of rBM-MSCs showed more developed and metabolically active cells.

A two-step strategy for neuronal differentiation in vitro of human dental follicle cells

Human dental follicle cells (DFCs) derived from wisdom teeth are precursor cells for cementoblasts. In this study, we recognized that naïve DFCs express constitutively the early neural cell marker beta-III-tubulin. Interestingly, DFCs formed beta-III-tubulin-positive neurosphere-like cell clusters (NLCCs) on low-attachment cell culture dishes in serum-replacement medium (SRM). For a detailed examination of the neural differentiation potential, DFCs were cultivated in different compositions of SRM containing supplements such as N2, B27, G5 and the neural stem cell supplement. Moreover, these cell culture media were combined with different cell culture substrates such as gelatin, laminin, poly-L-ornithine or poly-L-lysine. After cultivation in SRM, DFCs differentiated into cells with small cell bodies and long cellular extrusions. The expression of nestin, beta-III-tubulin, neuron-specific enolase (NSE) and neurofilament was up-regulated in SRM supplemented with G5, a cell culture supplement for glial cells, and the neural stem cell supplement. DFCs formed NLCCs and demonstrated an increased gene expression of neural cell markers beta-III-tubulin, NSE, nestin and for small neuron markers such as neuropeptides galanin (GAL) and tachykinin (TAC1) after cultivation on poly-L-lysine. For a further neural differentiation NLCC-derived cells were sub-cultivated on laminin and poly-L-ornithine cell culture substrate. After 2 weeks of differentiation, DFCs exposed neural-like cell morphology with small neurite-like cell extrusions. These cells differentially express neurofilament and NSE, but only low levels of beta-III-tubulin and nestin. In conclusion, we demonstrated the differentiation of human DFCs into neuron-like cells after a two-step strategy for neuronal differentiation.

Toxicity and intraocular properties of a novel long-acting anti-proliferative and anti-angiogenic compound IMS2186

PURPOSE

To investigate the intraocular properties and toxicity of IMS2186, a small molecule developed as an anti-choroidal neovascularization (anti-CNV) drug.

MATERIALS AND METHODS

Cellular toxicity and mechanism of action was tested on cell lines in vitro. Intraocular studies used rabbits for drug dissolution as well as toxicity and rats for the treatment study as well as the toxicity confirmation study. Rabbits' eyes were injected with 2.5 mg of IMS2186 and observed for 36 weeks. Laser-induced CNV in rats was treated with IMS2186, Kenalog, or phosphate-buffered saline (pBS). Fluorescein angiography (FA) and immunohistochemical processing of the globes was performed.

RESULTS

The anti-proliferative IC(50) of IMS2186 for human fibroblast cells was 1.0-3.0 microM and 0.3-3.0 microM for human cancer cells; the IC(50) of IMS2186 to inhibit endothelial tube formation was 0.1-0.3 microM. The IC(50) of IMS2186 for inhibiting the production of pro-inflammatory cytokines was 0.3-1 microM. The IC(50) of IMS2186 for inhibiting macrophage migration was 1 micrM. These biological properties were not species specific. IMS2186 can be formulated as a suspension for long-lasting release and when delivered intraocularly, no intraocular toxicity was observed by slit lamp exam, fundus exam, intraocular pressure measurements, or by electroretinography. FA showed a reduction in the leakage in eyes treated with IMS2186 and triamcinolone acetonide; DAPI staining also showed significantly less cellularity in IMS2186-treated lesions as compared to PBS (p = 0.0025).

CONCLUSION

IMS2186 may be a safe intraocular therapeutic agent for intraocular proliferation and angiogenesis.

Stem cell sources and therapeutic approaches for central nervous system and neural retinal disorders

In the past decades, stem cell biology has made a profound impact on our views of mammalian development as well as opened new avenues in regenerative medicine. The potential of stem cells to differentiate into various cell types of the body is the principal reason they are being explored in treatments for diseases in which there may be dysfunctional cells and/or loss of healthy cells due to disease. In addition, other properties are unique to stem cells; their endogenous trophic support, ability to home to sites of pathological entities, and stability in culture, which allows genetic manipulation, are also being utilized to formulate stem cell-based therapy for central nervous system (CNS) disorders. In this review, the authors will review key characteristics of embryonic and somatic (adult) stem cells, consider therapeutic strategies employed in stem cell therapy, and discuss the recent advances made in stem cell-based therapy for a number of progressive neurodegenerative diseases in the CNS as well as neuronal degeneration secondary to other abnormalities and injuries. Although a great deal of progress has been made in our knowledge of stem cells and their utility in treating CNS disorders, much still needs to be elucidated regarding the biology of the stem cells and the pathogenesis of targeted CNS diseases to maximize therapeutic benefits. Nonetheless, stem cells present tremendous promise in the treatment of a variety of neurodegenerative diseases.