Proteomic profile of human stem cells from dental pulp and periodontal ligament

Proteome differences of dental stem cells between permanent and deciduous teeth by data-independent acquisition proteomics

Dental pulp stem cells hold significant prospects for tooth regeneration and repair. However, a comprehensive understanding of the molecular differences between dental pulp stem cells (DPSC, from permanent teeth) and stem cells from human exfoliated deciduous teeth (SHED, from deciduous teeth) remains elusive, which is crucial for optimizing their therapeutic potential. To address this gap, we employed a novel data-independent acquisition (DIA) proteomics approach to compare the protein expression profiles of DPSC and SHED. Based on nano-LC-MS/MS DIA proteomics, we identified over 7,000 proteins in both cell types. By comparing their expression levels, 209 differentially expressed proteins were identified. Subsequent Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, along with protein-protein interaction network construction, revealed significant metabolic differences and key regulatory nodes. DPSC exhibited significantly higher expression of proteins belonging to the NDUFB family, SMARC family, RPTOR and TLR3. These proteins are known to be involved in critical cellular processes such as mitochondrial energy metabolism, mTOR-related autophagy pathway, and innate immune response. Conversely, SHED displayed elevated expression of AKR1B family, which participated in glycerolipid metabolism and adipogenic differentiation, PRKG1, MGLL and UQCRB proteins associated with thermogenesis. These findings highlight the specific proteomic landscape of DPSC and SHED, suggesting their distinct biological roles and potential applications.

Impact of increasingly complex cell culture conditions on the proteome of human periodontal ligament stem cells

AIMS

Human periodontal ligament stem cells (hPDLSCs) exhibit an enormous potential to regenerate periodontal tissue. However, their translatability to the clinical setting is constrained by technical difficulties in standardizing culture conditions. The aim was to assess complex culture conditions using a proteomic-based protocol to standardize multi-layer hPDLSC cultivation methodology.

MATERIALS AND METHODS

hPDLSC-derived constructs were created with varying biological complexity. The simplest constructs were monolayer sheets of hPDLSCs cultured with fetal bovine serum (FBS) or Plasma Rich in Growth Factors supernatant (PRGFsn). The most complex constructs were triple-layered cell structures cultured with PRGFsn, with or without PRGF fibrin membrane (mPRGF). Ultrastructure and proteomic analyses were performed on these constructs.

RESULTS

PRGF supernatant improved protein expression related to extracellular matrix, adhesion, proliferation, and migration in hPDLSCs. PRGF fibrin scaffold upregulates proteins for cell activation, respiration, and electron transport. hPDLSCs on fibrin membrane show robust osteogenic potential through differential protein expression (ossification, tissue remodeling, morphogenesis, or cell migration) and overall homeostasis relative to less complex structures.

CONCLUSION

Our data reveal the far-reaching potential of 3-dimensional constructs in combination with PRGF technology in periodontal regenerative applications.

ATF3 affects osteogenic differentiation in inflammatory hPDLSCs by mediating ferroptosis via regulating the Nrf2/HO-1 signaling pathway

Activating transcription factor 3 (ATF3) has been identified as a regulator associated with osteoblast differentiation. However, the effects of ATF3 on the osteogenic differentiation and proliferation of human periodontal stem cells (hPDLSCs) in periodontitis have not been reported. With the purpose of establishing an in vitro model of periodontitis, hPDLSCs were challenged with lipopolysaccharide (LPS). The Cell Counting Kit-8 assay was applied to assess cell viability, while reverse transcription-quantitative PCR and western blotting were employed to detect ATF3 expression. Inflammatory release was assessed using ELISA, together with western blotting. Lipid peroxidation was explored using the C11 BODIPY 581/591 probe, biochemical kits, thiobarbituric acid reactive substances (TBARS) assay and DCFH-DA staining. Iron and Fe2+ levels, and the expression levels of ferroptosis-related proteins were measured using corresponding kits and western blotting. Osteogenic differentiative capability was evaluated using alkaline phosphatase staining, Alizarin red staining and western blotting. The expression levels of proteins associated with Nrf2/HO-1 signaling were identified using western blotting. The results indicated that ATF3 expression was upregulated in LPS-induced hPDLSCs. The knockdown of ATF3 alleviated the LPS-induced inflammatory response in hPDLSCs, together with increased levels of TNF-α, IL-6, IL-1β, Cox-2 and iNOS, and decreased levels of IL-10. ATF3 silencing also led to lower TBARS production rate, and reduced levels of reactive oxygen species, iron, Fe2+, ACSL4 and TFR1, whereas it elevated the levels of SLC7A11 and GPX4. In addition, ATF3 silencing promoted hPDLSC mineralization and cell differentiation, and elevated the levels of OCN2, RUNX2 and BMP2. Additionally, ATF3 depletion upregulated the expression levels of proteins related with Nrf2/HO-1 signaling. The Nrf2 inhibitor ML385 partially counteracted the effects of ATF3 interference on the LPS-challenged inflammatory response, lipid peroxidation, ferroptosis as well as osteogenic differentiative capability in hPDLSCs. In summary, the results revealed that ATF3 silencing suppressed inflammation and ferroptosis, while it improved osteogenic differentiation in LPS-induced hPDLSCs by regulating Nrf2/HO-1 signaling, which may provide promising therapeutic targets for the treatment of periodontitis.

Human Periodontal Ligament Stem Cells (hPDLSCs) Spontaneously Differentiate into Myofibroblasts to Repair Diabetic Wounds

Advanced glycation end product (AGE) accumulation due to diabetes causes vascular and neurological lesions, delaying healing. The use of stem cells could overcome these problems. Although many studies have shown the potential beneficial effects of stem cell therapies in the treatment of chronic and refractory skin ulcers, their delivery methods are still under investigation. Human periodontal ligament stem cells (hPDLSCs) can spontaneously differentiate into myofibroblasts in specific cultures; therefore, they have the potential to effectively treat diabetic wounds and may also have applications in the field of medical cosmetics. The myofibroblastic differentiation ability of hPDLSCs in the presence of AGEs was evaluated by the expression of α-SMA and COL1A1 using RT-qPCR and WB technology. Wound healing in diabetic mice, induced by streptozotocin (STZ) and assessed using H&E staining, Masson staining, and immunohistochemical (IHC) and immunofluorescence (IF) staining, was used to validate the effects of hPDLSCs. In the wound tissues, the expression of α-SMA, COL1A1, CD31, CD206, iNOS, and vimentin was detected. The findings indicated that in H-DMEM, the expression of COL1A1 exhibited a significant decrease, while α-SMA demonstrated an increase in P7 cells, ignoring the damage from AGEs (p < 0.05). In an STZ-induced diabetic C57BL/6J mice whole-skin defect model, the healing rate of the hPDLSCs treatment group was significantly higher than that in the models (on the 7th day, the rate was 65.247% vs. 48.938%, p < 0.05). hPDLSCs have been shown to spontaneously differentiate into myofibroblasts in H-DMEM and resist damage from AGEs in both in vivo and in vitro models, suggesting their potential in the field of cosmetic dermatology.

Determinants of Dental Pulp Stem Cell Heterogeneity

INTRODUCTION

The aim of this review is to provide a narrative review on the determinants of dental pulp stem cell (DPSC) heterogeneity that may affect the regenerative properties of these cells.

METHODS

PubMed, Scopus and Medline (Ovid) literature searches were done on human dental pulp stem cell (hDPSC) heterogeneity. The focus was on human dental pulp stem cells (hDPSCs) with a primary focus on DPSC heterogeneity.

RESULTS

DPSCs display significant heterogeneity as illustrated by the various subpopulations reported, including differences in proliferation and differentiation capabilities and the impact of various intrinsic and extrinsic factors.

CONCLUSIONS

The lack of consistent and reliable results in the clinical setting may be due to the heterogeneous nature of DPSC populations. Standardization in isolation techniques and in criteria to characterize DPSCs should lead to less variability in results reported and improve comparison of findings between studies. Single-cell RNA sequencing holds promise in elucidating DPSC heterogeneity and may contribute to the establishment of standardized techniques.