Cementoblastic lineage formation in the cross-talk between stem cells of human exfoliated deciduous teeth and epithelial rests of Malassez cells.

OBJECTIVES: The purpose of this study was to evaluate the synergistic effect of epithelial rests of Malassez cells (ERM) and transforming growth factor-ß1 (TGF-ß1) on proliferation, cementogenic and osteogenic differentiation of stem cells derived from human exfoliated deciduous teeth (SHED). MATERIALS AND METHODS: SHED were co-cultured with ERM with/without TGF-ß1. Then, SHED proliferation, morphological appearance, alkaline phosphatase (ALP) activity, mineralization behaviour and gene/protein expression of cemento/osteoblastic phenotype were evaluated. RESULTS: TGF-ß1 enhanced SHED proliferation when either cultured alone or co-cultured with ERM. ERM induced the cementoblastic differentiation of SHED which was significantly accelerated when treated with TGF-ß1. This activity was demonstrated by high ALP activity, strong mineral deposition and upregulation of cementum/bone-related gene and protein expressions (i.e. ALP, collagen type I, bone sialoprotein, osteocalcin and cementum attachment protein). CONCLUSIONS: ERM were able to induce SHED differentiation along the cemento/osteoblastic lineage that was triggered in the presence of TGF-ß1. CLINICAL RELEVANCE: The cemento/osteoblastic differentiation capability of SHED possesses a therapeutic potential in endodontic and periodontal tissue engineering.

Antibacterial and Immunomodulatory Properties of Stem Cells from Human Exfoliated Deciduous Teeth: An In Vitro Study.

Stem cells from human exfoliated deciduous teeth (SHED) provide an important autologous source for stem cell-based regenerative therapies with their easy acquisition and multipotency. However, the understanding of their antibacterial and immunomodulatory properties is limited. This in vitro research aims to determine whether SHED inhibits the growth of Streptococcus mutans (S. mutans) and Enterococcus faecalis (E. faecalis), as well as whether or not it has immunomodulatory effects by measuring interleukins (ILs)-2 and -6 levels. SHEDs were derived from the pulp of deciduous teeth that had undergone up to two-thirds of their roots' resorption. Isolated SHEDs were characterized on their morphological features, viability, assessment of surface markers, and in vitro induction into osteocytes and adipocytes. SHED was tested for its antibacterial efficacy against S. mutans and E. faecalis using a colony-forming units (CFU) assay. Lastly, we checked the cytokine levels by enzyme-linked immune sorbent assay (ELISA) for assessing the immunomodulatory properties of SHED. The results showed that the established SHED had fibroblastic morphology with higher viability. The ability to differentiate into osteocytes and adipocytes, as well as the expression of stem cell-specific markers, demonstrated their potential and flexibility under in vitro settings. SHED demonstrated antibacterial characteristics by significantly (p < 0.05) lowering S. mutans CFU, whereas E. faecalis CFU was either unaffected by or just slightly affected by the cells. SHED also helped keep inflammatory indicators, including IL-2 and IL-6, at stable levels when compared to the control. The results indicate that SHED may aid in preventing or reducing an infection due to its antibacterial activity and may provide immunomodulatory activities by controlling the production of cytokines. How to cite this article: Tyagi A, Shetty J, Shetty S, et al. Antibacterial and Immunomodulatory Properties of Stem Cells from Human Exfoliated Deciduous Teeth: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(S-3):S240-S246.

Effect of ciliary neurotrophic factor on neural differentiation of stem cells of human exfoliated deciduous teeth.

The stem cells of human exfoliated deciduous teeth (SHEDs) are considered to be one of the main sources of seed cells in stem cell therapy. The aim of this study was to examine the effect of ciliary neurotrophic factor (CNTF) on neurogenic differentiation of SHEDs. With the consent of parents, SHEDs from 6 to 8 year old children were isolated and cultured. The mesenchymal stemness and the potential of multidirectional (adipogenic and osteogenic) differentiation for the isolated SHEDs were firstly determined. The effect of CNTF on specific neurogenic differentiation of SHEDs was then examined by detecting the expression of marker genes and proteins via RT-PCR, immunoblotting, and immunofluorescence microscopy. The isolated SHEDs expressed specific surface markers of mesenchymal stem cells, and their potential of osteogenic and adipogenic differentiation were confirmed. CNTF promoted the differentiation of SHEDs into neuron-like cells with a high expression of acetylcholine transferase (CHAT), a marker of cholinergic neurons. The expression of other neuron markers including nestin, microtubule-associated protein 2 (MAP 2), and ß-tublin III was also detected. Interestingly, the expression of neurogenic markers was maintained at a high level after neurogenic induction. SHEDs can be induced by CNTF to differentiate into cholinergic neuron-like cells under appropriate culture conditions. Our findings have laid a foundation for future use of SHEDs to treat neurological diseases.

Comparative Immunophenotypic Characteristics, Proliferative Features, and Osteogenic Differentiation of Stem Cells Isolated from Human Permanent and Deciduous Teeth with Bone Marrow.

To find out differences and similarities in phenotypic, proliferative, and trans-differentiation properties of stem cells isolated from pulp of deciduous (SHEDs) and permanent (DPSCs) teeth with human bone marrow stem cells (BMSCs), we examined the expression of mesenchymal and embryonic stem cell markers in relation to the proliferation and osteogenic differentiation potentials of these cells. In this way, after isolating SHEDs, DPSCs, and BMSCs, cell proliferation was evaluated and population doubling time was calculated accordingly. Expression patterns of mesenchymal, hematopoietic, and embryonic stem cell markers were assessed followed by examining differentiation potential toward osseous tissue through alizarin red staining and qRT-PCR. Based on the results, the proliferation rates of SHEDs and DPSCs were significantly higher than that of BMSCs (P < 0.0001). High expression of mesenchymal stem cell markers and weak expression of hematopoietic markers were observed in all the three groups. The mean expression of OCT-4 was significantly higher in SHEDs and DPSCs (P = 0.028), while the expression of SSEA-4 was lower (P = 0.006) compared to BMSCs. Osteogenic differentiation potential of SHEDs was greater than DPSCs; however, it was lower than that of BMSCs. Conclusively, the distinctive immunophenotyping, proliferation rate, and differentiation pattern of SHEDs and DPSCs discriminate these cells from BMSCs. Furthermore, dissimilarity in differentiation potential is evidence implying that SHEDs might be more primitive stem cell population compared to DPSCs.

Stem cells as a good tool to investigate dysregulated biological systems in autism spectrum disorders.

Identification of the causes of autism spectrum disorders (ASDs) is hampered by their genetic heterogeneity; however, the different genetic alterations leading to ASD seem to be implicated in the disturbance of common molecular pathways or biological processes. In this scenario, the search for differentially expressed genes (DEGs) between ASD patients and controls is a good alternative to identify the molecular etiology of such disorders. Here, we employed genome-wide expression analysis to compare the transcriptome of stem cells of human exfoliated deciduous teeth (SHEDs) of idiopathic autistic patients (n = 7) and control samples (n = 6). Nearly half of the 683 identified DEGs are expressed in the brain (P = 0.003), and a significant number of them are involved in mechanisms previously associated with ASD such as protein synthesis, cytoskeleton regulation, cellular adhesion and alternative splicing, which validate the use of SHEDs to disentangle the causes of autism. Autistic patients also presented overexpression of genes regulated by androgen receptor (AR), and AR itself, which in turn interacts with CHD8 (chromodomain helicase DNA binding protein 8), a gene recently shown to be associated with the cause of autism and found to be upregulated in some patients tested here. These data provide a rationale for the mechanisms through which CHD8 leads to these diseases. In summary, our results suggest that ASD share deregulated pathways and revealed that SHEDs represent an alternative cell source to be used in the understanding of the biological mechanisms involved in the etiology of ASD.