Cells isolated from cryopreserved dental follicle display similar characteristics to cryopreserved dental follicle cells

Dental follicle tissue is a promising resource of mesenchymal stem cells for cytotherapeutic approaches and tissue engineering applications. There are two procedures for banking of human dental follicle stem cells have been reported. Conventional method requires cell isolation, expansion and immediate cryopreservation. Whereas dental follicle stem cells can be isolated from cryopreserved dental follicle fragments. The aim of this study was to compare the characteristics of dental follicle cells isolated from cryopreserved fragments (DFCs-CF) with dental follicle cells recovered from cryopreserved cells (DFCs-CC). Dental follicle fragments obtained after mechanical disaggregation were divided into two parts, with one part maintained in culture, while another part underwent cryopreservation. Dental follicle fragments and dental follicle cells from fresh tissue were stored in liquid nitrogen for 3 months. After thawing, the isolation, morphology, proliferation, cell cycle, colony-forming-unit ability, stemness-related marker expression, apoptosis, and multi-lineage differentiation potential of DFCs-CF were tested compared with DFCs-CC. DFCs-CF expressed mesenchymal stem cells marker, proliferated well, showed similar levels of mRNA for stemness- and apoptosis-related genes and exhibited the capacity of multi-lineage differentiation similar to those of DFCs-CC. These results imply that cryopreservation of dental follicle fragments is an effective banking method for isolation of dental follicle 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 β-III-tubulin. Interestingly, DFCs formed β-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, β-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 β-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 β-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.     

Neurogenic differentiation of murine and human adipose-derived stromal cells

The identification of cells capable of neuronal differentiation has great potential for cellular therapies. We examined whether murine and human adipose-derived adult stem (ADAS) cells can be induced to undergo neuronal differentiation. We isolated ADAS cells from the adipose tissue of adult BalbC mice or from human liposuction tissue and induced neuronal differentiation with valproic acid, butylated hydroxyanisole, insulin, and hydrocortisone. As early as 1-3 h after neuronal induction, the phenotype of ADAS cells changed towards neuronal morphology. Following neuronal induction, muADAS cells displayed immunocytochemical staining for GFAP, nestin and NeuN and huADAS cells displayed staining for intermediate filament M, nestin, and NeuN. Following neuronal induction of murine and human ADAS cells, Western blot analysis confirmed GFAP, nestin, and NeuN protein expression. Pretreatment with EGF and basic FGF augmented the neuronal differentiation of huADAS cells. The neuronal differentiation of stromal cells from adipose tissue has broad biological and clinical implications.     

Nestin Modulates Glucocorticoid Receptor Function by Cytoplasmic Anchoring

Nestin is the characteristic intermediate filament (IF) protein of rapidly proliferating progenitor cells and regenerating tissue. Nestin copolymerizes with class III IF-proteins, mostly vimentin, into heteromeric filaments. Its expression is downregulated with differentiation. Here we show that a strong nestin expression in mouse embryo tissue coincides with a strong accumulation of the glucocorticoid receptor (GR), a key regulator of growth and differentiation in embryonic development. Microscopic studies on cultured cells show an association of GR with IFs composed of vimentin and nestin. Cells lacking nestin, but expressing vimentin, or cells expressing vimentin, but lacking nestin accumulate GR in the nucleus. Completing these networks with an exogenous nestin, respectively an exogenous vimentin restores cytoplasmic anchoring of GR to the IF system. Thus, heteromeric filaments provide the basis for anchoring of GR. The reaction pattern with phospho-GR specific antibodies and the presence of the chaperone HSC70 suggest that specifically the unliganded receptor is anchored to the IF system. Ligand addition releases GR from IFs and shifts the receptor into the nucleus. Suppression of nestin by specific shRNA abolishes anchoring of GR, induces its accumulation in the nucleus and provokes an irreversible G1/S cell cycle arrest. Suppression of GR prior to that of nestin prevents entry into the arrest. The data give evidence that nestin/vimentin specific anchoring modulates growth suppression by GR. We hypothesize that expression of nestin is a major determinant in suppression of anti-proliferative activity of GR in undifferentiated tissue and facilitates activation of this growth control in a precise tissue and differentiation dependent manner.