Self-Renewal and Multipotency Coexist in a Long-Term Cultured Adult Rat Dental Pulp Stem Cell Line: An Exception to the Rule?

Sinking Our Teeth in Getting Dental Stem Cells to Clinics for Bone Regeneration

Dental stem cells have been isolated from the medical waste of various dental tissues. They have been characterized by numerous markers, which are evaluated herein and differentiated into multiple cell types. They can also be used to generate cell lines and iPSCs for long-term in vitro research. Methods for utilizing these stem cells including cellular systems such as organoids or cell sheets, cell-free systems such as exosomes, and scaffold-based approaches with and without drug release concepts are reported in this review and presented with new pictures for clarification. These in vitro applications can be deployed in disease modeling and subsequent pharmaceutical research and also pave the way for tissue regeneration. The main focus herein is on the potential of dental stem cells for hard tissue regeneration, especially bone, by evaluating their potential for osteogenesis and angiogenesis, and the regulation of these two processes by growth factors and environmental stimulators. Current in vitro and in vivo publications show numerous benefits of using dental stem cells for research purposes and hard tissue regeneration. However, only a few clinical trials currently exist. The goal of this review is to pinpoint this imbalance and encourage scientists to pick up this research and proceed one step further to translation.

Dental pulp stem cells (DPSCs) increase prostate cancer cell proliferation and migration under in vitro conditions

Cancer as a multistep and complicated disease is regulated by several molecular and cellular events. Cancer treatment could be managed at the early stages when the tumor is confined in the tissue. However, disseminated cancer cells metastasize to other body parts and generate new tumors resulting in mortality. Mesenchymal stem cells (MSCs) are found in different body parts and helps adult tissue regeneration. The role of MSCs in cancer progression has emerged as one of the important aspects in cancer biology and is the aim of interest in recent years. In the current study, effects of Dental Pulp Stem Cells (DPSCs) on PC-3 prostate cancer cell proliferation and migration were conducted by cell proliferation, apoptosis, gene expression and cell migration analysis in vitro. Condition medium (CM) obtained from DPSCs increased cell proliferation of PC-3 cells and decreased apoptosis. Either administration of CM or trans well co-culture of DPSCs increased cell migration in scratch assay, confirmed by gene expression analysis of migratory genes including fibronectin, laminin and collagen type I (Col I). Furthermore, DPSCs participated in a self-organized structure with PC-3 cells in co-culture conditions. Overall, results indicated that DPSCs could promote PC-3 cancer cell proliferation and metastasis in co-culture conditions in vitro.

A Simple Protocol to Isolate, Characterize, and Expand Dental Pulp Stem Cells

Adult stem cells reside in body tissues to preserve organs and whole organism homeostasis. They are acquiring a prominent role in the contemporary medicine. Many protocols to isolate and cultivate adult stem cells have been so far described, though they are often lengthy, laborious, and require very expansive instruments, materials, and reagents. On this basis, we describe a simple, cheap but at the same time functional method to: (1) isolate dental pulp stem cells (DPSC), (2) expand and cultivate DPSC, (3) cryopreserve DPSC, (4) characterize DPSC, and (5) differentiate DPSC into both mesenchymal and non-mesenchymal lineages.

Odontogenic stimulation of human dental pulp cells with bioactive nanocomposite fiber

The aim of the present study was to investigate the effects of a composite nanofibrous matrix made of biopolymer blend polycaprolactone-gelatin (BP) and mesoporous bioactive glass nanoparticles (BGNs) on the odontogenic differentiation of human dental pulp cells (HDPCs). BGN-BP nanomatrices, with BGN content of up to 20 wt%, were produced via electrospinning. The differentiation of the HDPCs was evaluated by using an ALP activity assay, calcified nodule formation, and mRNA expression for markers. Integrin and its underlying signal pathways were assessed via reverse transcriptase-polymerase chain reaction and Western blot analysis. Although cell growth and attachment on the BGN-BP nanomatrix was similar to that on BP, ALP activity, mineralized nodule formation, and mRNA, expressions involving ALP, osteocalcin, osteopontin, dentin sialophosphoprotein, and dentin matrix protein-1 were greater on BGN-BP. BGN-BP upregulated the key adhesion receptors (integrin components α1, α2, α5, and β1) and activated integrin downstream pathways, such as phosphorylated-focal adhesion kinase (p-FAK), and p-paxillin. In addition, BGN-BP activated BMP receptors, BMP-2 mRNA, and p-Smad 1/5/8, and such activation was blocked by the BMP antagonist, noggin. Furthermore, BGN-BP induced phosphorylation of extracellular signal-regulated kinase, protein kinase 38, and c-Jun-N-terminal kinase mitogen-activated protein kinases and activated expression of the transcription factors Runx2 and Osterix in HDPCs. Collectively, the results indicated for the first time that a BGN-BP composite nanomatrix promoted odontogenic differentiation of HDPCs through the integrin, BMP, and mitogen-activated protein kinases signaling pathway. Moreover, the nanomatrix is considered to be promising scaffolds for the culture of HDPCs and dental tissue engineering.

Isolation and characterization of a spontaneously immortalized multipotent mesenchymal cell line derived from mouse subcutaneous adipose tissue

The emerging field of tissue engineering and regenerative medicine is a multidisciplinary science that is based on the combination of a reliable source of stem cells, biomaterial scaffolds, and cytokine growth factors. Adult mesenchymal stem cells are considered important cells for applications in this field, and adipose tissue has revealed to be an excellent source of them. Indeed, adipose-derived stem cells (ASCs) can be easily isolated from the stromal vascular fraction (SVF) of adipose tissue. During the isolation and propagation of murine ASCs, we observed the appearance of a spontaneously immortalized cell clone, named m17.ASC. This clone has been propagated for more than 180 passages and stably expresses a variety of stemness markers, such as Sca-1, c-kit/CD117, CD44, CD106, islet-1, nestin, and nucleostemin. Furthermore, these cells can be induced to differentiate toward osteogenic, chondrogenic, adipogenic, and cardiogenic phenotypes. m17.ASC clone displays a normal karyotype and stable telomeres; it neither proliferates when plated in soft agar nor gives rise to tumors when injected subcutaneously in NOD/SCID-γ (null) mice. The analysis of gene expression highlighted transcriptional traits of SVF cells. m17.ASCs were genetically modified by lentiviral vectors carrying green fluorescent protein (GFP) as a marker transgene and efficiently engrafted in the liver, when injected in the spleen of NOD/SCID-γ (null) monocrotaline-treated mice. These results suggest that this non-tumorigenic spontaneously immortalized ASC line may represent a useful tool (cell model) for studying the differentiation mechanisms involved in tissue repair as well as a model for pharmacological/toxicological studies.

Potentiation of amyloid-β peptide neurotoxicity in human dental-pulp neuron-like cells by the membrane lipid peroxidation product 4-hydroxynonenal

Lipid peroxidation is generally considered as primarily implicated in the pathogenesis of Alzheimer's disease (AD); one of its more reactive end products, 4-hydroxynonenal (HNE), has been shown to cause neuron dysfunction and degeneration. HNE production in the brain is stimulated by the amyloid-β peptide (Aβ), whose excessive accumulation in specific brain areas is a hallmark of AD. Conversely, Aβ production is up-regulated by this multifunctional aldehyde. Findings reported here point to the ability of HNE and Aβ to interact, with consequent potentiation of Aβ's cytotoxicity as determined in vitro using neuron-like cells derived from human dental-pulp progenitor cells. Preincubation of cells with the aldehyde markedly up-regulated Aβ uptake and intracellular accumulation, by overexpressing two of the three components of the plasma membrane multireceptor complex CD36/CD47/β1-integrin: experimental and clinical data indicate that intraneuronal accumulation of Aβ is an early event possibly playing a primary role in AD pathogenesis. That HNE-mediated overexpression of CD36 and β1-integrin, which plays a key role in HNE's potentiating Aβ neurotoxicity, in terms of necrosis, was confirmed when this effect was prevented by specific antibodies against the two receptors.