Cannabidiol Modulates the Immunophenotype and Inhibits the Activation of the Inflammasome in Human Gingival Mesenchymal Stem Cells

Biofunctionalized Scaffold in Bone Tissue Repair

Bone tissue engineering is based on bone grafting to repair bone defects. Bone graft substitutes can contribute to the addition of mesenchymal stem cells (MSCs) in order to enhance the rate and the quality of defect regeneration. The stem cell secretome contains many growth factors and chemokines, which could affect cellular characteristics and behavior. Conditioned medium (CM) could be used in tissue regeneration avoiding several problems linked to the direct use of MSCs. In this study, we investigated the effect of human periodontal ligament stem cells (hPDLSCs) and their CM on bone regeneration using a commercially available membrane scaffold Evolution (EVO) implanted in rat calvarias. EVO alone or EVO + hPDLSCs with or without CM were implanted in Wistar male rats subjected to calvarial defects. The in vivo results revealed that EVO membrane enriched with hPDLSCs and CM showed a better osteogenic ability to repair the calvarial defect. These results were confirmed by acquired micro-computed tomography (CT) images and the increased osteopontin levels. Moreover, RT-PCR in vitro revealed the upregulation of three genes (Collagen (COL)5A1, COL16A1 and transforming growth factor (TGF)β1) and the down regulation of 26 genes involved in bone regeneration. These results suggest a promising potential application of CM from hPDLSCs and scaffolds for bone defect restoration and in particular for calvarial repair in case of trauma.

Repeated stimulation by LPS promotes the senescence of DPSCs via TLR4/MyD88-NF-κB-p53/p21 signaling

Dental pulp stem cells (DPSCs), one type of mesenchymal stem cells, are considered to be a type of tool cells for regenerative medicine and tissue engineering. Our previous studies found that the stimulation with lipopolysaccharide (LPS) might introduce senescence of DPSCs, and this senescence would have a positive correlation with the concentration of LPS. The β-galactosidase (SA-β-gal) staining was used to evaluate the senescence of DPSCs and immunofluorescence to show the morphology of DPSCs. Our findings suggested that the activity of SA-β-gal has increased after repeated stimulation with LPS and the morphology of DPSCs has changed with the stimulation with LPS. We also found that LPS bound to the Toll-like receptor 4 (TLR4)/myeloid differentiation factor (MyD) 88 signaling pathway. Protein and mRNA expression of TLR4, MyD88 were enhanced in DPSCs with LPS stimulation, resulting in the activation of nuclear factor-κB (NF-κB) signaling, which exhibited the expression of p65 improved in the nucleus while the decreasing of IκB-α. Simultaneously, the expression of p53 and p21, the downstream proteins of the NF-κB signaling, has increased. In summary, DPSCs tend to undergo senescence after repeated stimulation in an inflammatory microenvironment. Ultimately, these findings may lead to a new direction for cell-based therapy in oral diseases and other regenerative medicines.

Biotherapeutic Effect of Gingival Stem Cells Conditioned Medium in Bone Tissue Restoration

Bone tissue engineering is one of the main branches of regenerative medicine. In this field, the use of a scaffold, which supported bone development, in combination with mesenchymal stem cells (MSCs), has promised better outcomes for bone regeneration. In particular, human gingival mesenchymal stem cells (hGMSCs) may present advantages compared to other MSCs, including the easier isolation. However, MSCs’ secretome has attracted much attention for its potential use in tissue regeneration, such as conditioned medium (CM) that contains different soluble factors proved to be useful for the regenerative purposes. In this study, we evaluated the osteogenic capacity of a poly-(lactide) (3D-PLA) scaffold enriched with hGMSCs and hGMSCs derived CM and its ability to regenerate bone defects in rat calvarias. 3D-PLA alone, 3D-PLA + CM or 3D-PLA + hGMSCs with/without CM were implanted in Wistar male rats subjected to calvarial defects. We observed that 3D-PLA scaffold enriched with hGMSCs and CM showed a better osteogenic capacity, being able to repair the calvarial defect as revealed in vivo by morphological evaluation. Moreover, transcriptomic analysis in vitro revealed the upregulation of genes involved in ossification and regulation of ossification in the 3D-PLA + CM + hGMSCs group. All of these results indicate the great osteogenic ability of 3D-PLA + CM + hGMSCs supporting its use in bone regenerative medicine, in particular in the repair of cranial bone defects. Especially, hGMSCs derived CM played a key role in the induction of the osteogenic process and in bone regeneration.

High-throughput immunophenotypic characterization of bone marrow- and cord blood-derived mesenchymal stromal cells reveals common and differentially expressed markers: identification of angiotensin-converting enzyme (CD143) as a marker differentially expressed between adult and perinatal tissue sources

BACKGROUND

Mesenchymal stromal cells (MSC) are a heterogeneous population of multipotent progenitors used in the clinic because of their immunomodulatory properties and their ability to differentiate into multiple mesodermal lineages. Although bone marrow (BM) remains the most common MSC source, cord blood (CB) can be collected noninvasively and without major ethical concerns. Comparative studies comprehensively characterizing the MSC phenotype across several tissue sources are still lacking. This study provides a 246-antigen immunophenotypic analysis of BM- and CB-derived MSC aimed at identifying common and strongly expressed MSC markers as well as the existence of discriminating markers between the two sources.

METHODS

BM-MSC (n = 4) were expanded and analyzed as bulk (n = 6) or single clones isolated from the bulk culture (n = 3). CB-MSC (n = 6) were isolated and expanded as single clones in 5/6 samples. The BM-MSC and CB-MSC phenotype was investigated by flow cytometry using a panel of 246 monoclonal antibodies. To define the markers common to both sources, those showing the smallest variation between samples (coefficient of variation of log₂ fold increase ≤ 0.5, n = 59) were selected for unsupervised hierarchical cluster analysis (HCL). Differentially expressed markers were identified by directly comparing the expression of all 246 antigens between BM-MSC and CB-MSC.

RESULTS

Based on HCL, 18 markers clustered as strongly expressed in BM-MSC and CB-MSC, including alpha-smooth muscle antigen (SMA), beta-2-microglobulin, CD105, CD13, CD140b, CD147, CD151, CD276, CD29, CD44, CD47, CD59, CD73, CD81, CD90, CD98, HLA-ABC, and vimentin. All except CD140b and alpha-SMA were suitable for the specific identification of ex-vivo expanded MSC. Notably, only angiotensin-converting enzyme (CD143) was exclusively expressed on BM-MSC. CD143 expression was tested on 10 additional BM-MSC and CB-MSC and on 10 umbilical cord- and adipose tissue-derived MSC samples, confirming that its expression is restricted to adult sources.

CONCLUSIONS

This is the first study that has comprehensively compared the phenotype of BM-MSC and CB-MSC. We have identified markers that could complement the minimal panel proposed for the in-vitro MSC definition, being shared and strongly expressed by BM- and CB-derived MSC. We have also identified CD143 as a marker exclusively expressed on MSC derived from adult tissue sources. Further studies will elucidate the biological role of CD143 and its potential association with tissue-specific MSC features.

Conditioned medium from human gingival mesenchymal stem cells protects motor-neuron-like NSC-34 cells against scratch-injury-induced cell death

Neuronal cell death is a normal process during central nervous system (CNS) development and is also involved in the death of motor neurons in diverse spinal motor neuron degenerative diseases. Here, we investigated the neuroprotective effect of secretory factors released from human gingival mesenchymal stem cells (hGMSCs) in mechanically injured murine motor-neuron-like NSC-34 cells. The cells were exposed to scratch injury and the markers for apoptosis and oxidative stress were examined. Immunocytochemistry results showed that proapoptotic markers cleaved caspase-3 and Bax were elevated while anti-apoptotic protein Bcl-2 was suppressed in scratch-injured NSC-34 cells. Oxidative stress markers SOD-1, inducible nitric oxide synthase (iNOS), Cox-2, and proinflammatory cytokine tumor necrosis factor alpha (TNF-α) were activated. Conditioned medium (CM) derived from hGMSCs (hGMSC-CM) significantly blocked the cell death by suppressing SOD-1, iNOS, TNF-α, cleaved caspase-3, and Bax. Bcl-2 and anti-inflammatory cytokine anti-interleukin 10 (IL-10) were increased in hGMSC-CM-treated injured cells. Moreover, hGMSC-CM treatment upregulated neurotrophins anti-brain-derived neurotrophic factor (BDNF) and NT3. Western blot data of hGMSC-CM revealed the presence of neurotrophins nerve growth factor (NGF), NT3, anti-inflammatory cytokines IL-10, and transforming growth factor beta (TGF-β), suggesting their positive role to elicit neuroprotection. Our results propose that hGMSC-CM may serve as a simple and potential autologous therapeutic tool to treat motor neuron injury.

Transcriptomic analysis of gingival mesenchymal stem cells cultured on 3D bioprinted scaffold: A promising strategy for neuroregeneration

The combined approach of mesenchymal stem cells (MSCs) and scaffolds has been proposed as a potential therapeutic tool for the treatment of neurodegenerative diseases. Indeed, even if MSCs can promote neuronal regeneration, replacing lost neurons or secreting neurotrophic factors, many limitations still exist for their application in regenerative medicine, including the low survival and differentiation rate. The scaffolds, by mimicking the endogenous microenvironment, have shown to promote cell survival, proliferation, and differentiation. In this work, gingival mesenchymal stem cells (GMSCs), isolated from healthy donors, were expanded in vitro, by culturing them adherent in plastic dishes (CTR-GMSCs) or on a poly(lactic acid) scaffold (SC-GMSCs). In order to evaluate the survival and the neurogenic differentiation potential, we performed a comparative transcriptomic analysis between CTR-GMSCs and SC-GMSCs by next generation sequencing. We found that SC-GMSCs showed an increased expression of neurogenic and prosurvival genes. In particular, genes involved in neurotrophin signaling and PI3K/Akt pathways were upregulated. On the contrary, proapoptotic and negative regulator of neuronal growth genes were downregulated. Moreover, nestin and GAP-43 protein levels increased in SC-GMSCs, confirming the neurogenic commitment of these cells. In conclusion, the scaffold, providing a trophic support for MSCs, may promote GMSCs differentiation toward a neuronal phenotype and survival. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 126-137, 2018.

Porphyromonas gingivalis lipopolysaccharide stimulation in human periodontal ligament stem cells: role of epigenetic modifications to the inflammation

Periodontitis is a chronic oral inflammatory disease produced by bacteria. Gingival retraction and bone and connective tissues resorption are the hallmarks of this disease. Chronic periodontitis may contribute to the risk of onset or progression of neuroinflammatory pathological conditions, such as Alzheimer’s disease. The main goal of the present study was to investigate if the role of epigenetic modulations is involved in periodontitis using human periodontal ligament stem cells (hPDLSCs) as an in vitro model system. hPDLSCs were treated with lipopolysaccharide of Porphyromonas gingivalis and the expression of proteins associated with DNA methylation and histone acetylation, such as DNMT1 and p300, respectively, and inflammatory transcription factor NF-kB, were examined. Immunofluorescence, Western blot and next generation sequencing results demonstrated that P. gingivalis lipopolysaccharide significantly reduced DNA methylase DNMT1, while it markedly upregulated the level of histone acetyltransferase p300 and NF-kB in hPDLSCs. Our results showed that P. gingivalis lipopolysaccharide markedly regulate the genes involved in epigenetic mechanism, which may result in inflammation induction. We propose that P. gingivalis lipopolysaccharide-treated hPDLSCs could be a potential in vitro model system to study epigenetics modulations associated with periodontitis, which might be helpful to identify novel biomarkers linked to this oral inflammatory disease.