Bladder Smooth Muscle Cells Differentiation from Dental Pulp Stem Cells: Future Potential for Bladder Tissue Engineering. Stem Cells Int. 2016;2016:6979368. [PMID: 26880982 PMCID: PMC4736571 DOI: 10.1155/2016/6979368]

Effects of different signaling pathways on odontogenic differentiation of dental pulp stem cells: a review

Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cells that can differentiate into odontoblast-like cells and protect the pulp. The differentiation of DPSCs can be influenced by biomaterials or growth factors that activate different signaling pathways in vitro or in vivo. In this review, we summarized six major pathways involved in the odontogenic differentiation of DPSCs, Wnt signaling pathways, Smad signaling pathways, MAPK signaling pathways, NF-kB signaling pathways, PI3K/AKT/mTOR signaling pathways, and Notch signaling pathways. Various factors can influence the odontogenic differentiation of DPSCs through one or more signaling pathways. By understanding the interactions between these signaling pathways, we can expand our knowledge of the mechanisms underlying the regeneration of the pulp-dentin complex.

Markers of dental pulp stem cells in in vivo developmental context

Teeth and their associated tissues contain several populations of mesenchymal stem cells, one of which is represented by dental pulp stem cells (DPSCs). These cells have mainly been characterised in vitro and numerous positive and negati ve markers for these cells have been suggested. To investigate the presence and localization of these molecules during development, forming dental pulp was examined using the mouse first mandibular molar as a model. The stages corresponding to postnatal (P) days 0, 7, 14, and 21 were investigated. The expression was monitored using customised PCR Arrays. Additionally, in situ localization of the key trio of markers (Cd73, Cd90, Cd105 coded by genes Nt5e, Thy1, Eng) was performed at prenatal and postnatal stages using immunohistochemistry. The expression panel of 24 genes assigned as in vitro markers of DPSCs or mesenchymal stem cells (MSCs) revealed their developmental dynamics during formation of dental pulp mesenchyme. Among the positive markers, Vcam1, Fgf2, Nes were identified as increasing and Cd44, Cd59b, Mcam, Alcam as decreasing between perinatal vs. postnatal stages towards adulthood. Within the panel of negative DPSC markers, Cd14, Itgb2, Ptprc displayed increased and Cd24a decreased levels at later stages of pulp formation. Within the key trio of markers, Nt5e did not show any significant expression difference within the investigated period. Thy1 displayed a strong decrease between P0 and P7 while Eng increased between these stages. In situ localization of Cd73, Cd90 and Cd105 showed them overlap in differentiated odontoblasts and in the sub-odontoblastic layer that is speculated to host odontoblast progenitors. The highly prevalent expression of particularly Cd73 and Cd90 opens the question of potential multiple functions of these molecules. The results from this study add to the in vitro based knowledge by showing dynamics in the expression of DPSC/MSC markers during dental pulp formation in an in vivo context and thus with respect to the natural environment important for commitment of stem cells.

Effect of tetracycline hydrochloride application on dental pulp stem cell metabolism-booster or obstacle for tissue engineering?

Introduction: Stem cells and scaffolds are an important foundation and starting point for tissue engineering. Human dental pulp stem cells (DPSC) are mesenchymal stem cells with self-renewal and multi-directional differentiation potential, and are ideal candidates for tissue engineering due to their excellent biological properties and accessibility without causing major trauma at the donor site. Tetracycline hydrochloride (TCH), a broad-spectrum antibiotic, has been widely used in recent years for the synthesis of cellular scaffolds to reduce the incidence of postoperative infections. Methods: In order to evaluate the effects of TCH on DPSC, the metabolism of DPSC in different concentrations of TCH environment was tested. Moreover, cell morphology, survival rates, proliferation rates, cell migration rates and differentiation abilities of DPSC at TCH concentrations of 0-500 μg/ml were measured. Phalloidin staining, live-dead staining, MTS assay, cell scratch assay and real-time PCR techniques were used to detect the changes in DPSC under varies TCH concentrations. Results: At TCH concentrations higher than 250 μg/ml, DPSC cells were sequestered, the proportion of dead cells increased, and the cell proliferation capacity and cell migration capacity decreased. The osteogenic and adipogenic differentiation abilities of DPSC, however, were already inhibited at TCH con-centrations higher than 50 μg/ml. Here, the expression of the osteogenic genes, runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN), the lipogenic genes lipase (LPL), as well as the peroxisome proliferator-activated receptor-γ (PPAR-γ) expression were found to be down-regulated. Discussion: The results of the study indicated that TCH in concentrations above 50 µg/ml negatively affects the differentiation capability of DPSC. In addition, TCH at concentrations above 250 µg/ml adversely affects the growth status, percentage of living cells, proliferation and migration ability of cells.

Pleiotrophin attenuates the senescence of dental pulp stem cells

OBJECTIVES

Pleiotrophin (PTN), a secreted extracellular matrix-associated protein, plays an important role in regulating the osteo/dentinogenic differentiation potential of dental pulp stem cells (DPSCs). Our previous study has demonstrated that PTN expression in young DPSCs was is 10-fold higher than that in aged DPSCs. However, the role of PTN on the in maintaining the stemness of senescent DPSCs remains unclear. The present study aimed to investigate the effect of PTN on senescent DPSCs in vitro.

MATERIALS AND METHODS

Dental pulp stem cells were isolated from human third molars. PTN was knocked down using short hairpin RNAs to study the role of PTN on the senescence of DPSCs. DPSCs with aging performance were obtained by a replicative senescence cell model was obtained by the long-term culture of DPSCs to the 15th passage in vitro (P15). We then investigated the effect of PTN on senescent DPSCs (P15 DPSCs). Real-time RT-PCR, western blotting, alizarin red staining, quantitative calcium analysis, SA-β-Gal staining, CFSE, and cell-counting kit-8 (CCK8) assays were used to study cellular senescence and function.

RESULTS

The depletion of PTN increased the ratio of SA-β-gal-positive cells, upregulated the expression of p16, and down-regulated the expression of TERT and p-p38. Furthermore, 50 pg/ml of PTN recombinant protein rescued these changes the altered ratio of SA-β-gal-positive cells, decreased the expression of p16, enhanced TERT and p-p38 expression, as well as telomere activity, caused by PTN depletion and long-term culture. The15th passage cells displayed typical aging characteristic, including high ratio of SA-β-gal-positive cells, increased aging-related gene expression, decreased proliferation rate, high level of Cyclin D expression, and impaired osteo/dentinogenic differentiation potential. However, 50 pg/ml of PTN recombinant protein could partially reverse these alteration rescue these changes.

CONCLUSIONS

The present study demonstrated that PTN could protect DPSCs from senescence by improving the proliferation and osteo/dentinogenic differentiation ability, probably through the p38 MAPK pathway.

Botanicals and Oral Stem Cell Mediated Regeneration: A Paradigm Shift from Artificial to Biological Replacement

Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.

New therapeutic approach with extracellular vesicles from stem cells for interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic disorder characterized by suprapubic pain and urinary symptoms such as urgency, nocturia, and frequency. The prevalence of IC/BPS is increasing as diagnostic criteria become more comprehensive. Conventional pharmacotherapy against IC/BPS has shown suboptimal effects, and consequently, patients with end-stage IC/BPS are subjected to surgery. The novel treatment strategies should have two main functions, anti-inflammatory action and the regeneration of glycosaminoglycan and urothelium layers. Stem cell therapy has been shown to have dual functions. Mesenchymal stem cells (MSCs) are a promising therapeutic option for IC/BPS, but they come with several shortcomings, such as immune activation and tumorigenicity. MSC-derived extracellular vesicles (MSC-EVs) hold numerous therapeutic cargos and are thus a viable cell-free therapeutic option. In this review, we provide a brief overview of IC/BPS pathophysiology and limitations of the MSC-based therapies. Then we provide a detailed explanation and discussion of therapeutic applications of EVs in IC/BPS as well as the possible mechanisms. We believe our review will give an insight into the strengths and drawbacks of EV-mediated IC/BPS therapy and will provide a basis for further development.

New therapeutic approach with extracellular vesicles from stem cells for interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic disorder characterized by suprapubic pain and urinary symptoms such as urgency, nocturia, and frequency. The prevalence of IC/BPS is increasing as diagnostic criteria become more comprehensive. Conventional pharmacotherapy against IC/BPS has shown suboptimal effects, and consequently, patients with end-stage IC/BPS are subjected to surgery. The novel treatment strategies should have two main functions, anti-inflammatory action and the regeneration of glycosaminoglycan and urothelium layers. Stem cell therapy has been shown to have dual functions. Mesenchymal stem cells (MSCs) are a promising therapeutic option for IC/BPS, but they come with several shortcomings, such as immune activation and tumorigenicity. MSC-derived extracellular vesicles (MSC-EVs) hold numerous therapeutic cargos and are thus a viable cell-free therapeutic option. In this review, we provide a brief overview of IC/BPS pathophysiology and limitations of the MSC-based therapies. Then we provide a detailed explanation and discussion of therapeutic applications of EVs in IC/BPS as well as the possible mechanisms. We believe our review will give an insight into the strengths and drawbacks of EV-mediated IC/BPS therapy and will provide a basis for further development. [BMB Reports 2022; 55(5): 205-212].

Controlled Growth Factor Delivery and Cyclic Stretch Induces a Smooth Muscle Cell-like Phenotype in Adipose-Derived Stem Cells

Adipose-derived stem cells (ASCs) are an abundant and easily accessible multipotent stem cell source with potential application in smooth muscle regeneration strategies. In 3D collagen hydrogels, we investigated whether sustained release of growth factors (GF) PDGF-AB and TGF-β1 from GF-loaded microspheres could induce a smooth muscle cell (SMC) phenotype in ASCs, and if the addition of uniaxial cyclic stretch could enhance the differentiation level. This study demonstrated that the combination of cyclic stretch and GF release over time from loaded microspheres potentiated the differentiation of ASCs, as quantified by protein expression of early to late SMC differentiation markers (SMA, TGLN and smooth muscle MHC). The delivery of GFs via microspheres produced large ASCs with a spindle-shaped, elongated SMC-like morphology. Cyclic strain produced the largest, longest, and most spindle-shaped cells regardless of the presence or absence of growth factors or the growth factor delivery method. Protein expression and cell morphology data confirmed that the sustained release of GFs from GF-loaded microspheres can be used to promote the differentiation of ASCs into SMCs and that the addition of uniaxial cyclic stretch significantly enhances the differentiation level, as quantified by intermediate and late SMC markers and a SMC-like elongated cell morphology.

Considerations for the clinical use of stem cells in genitourinary regenerative medicine

The genitourinary tract can be affected by several pathologies which require repair or replacement to recover biological functions. Current therapeutic strategies are challenged by a growing shortage of adequate tissues. Therefore, new options must be considered for the treatment of patients, with the use of stem cells (SCs) being attractive. Two different strategies can be derived from stem cell use: Cell therapy and tissue therapy, mainly through tissue engineering. The recent advances using these approaches are described in this review, with a focus on stromal/mesenchymal cells found in adipose tissue. Indeed, the accessibility, high yield at harvest as well as anti-fibrotic, immunomodulatory and proangiogenic properties make adipose-derived stromal/SCs promising alternatives to the therapies currently offered to patients. Finally, an innovative technique allowing tissue reconstruction without exogenous material, the self-assembly approach, will be presented. Despite advances, more studies are needed to translate such approaches from the bench to clinics in urology. For the 21^st century, cell and tissue therapies based on SCs are certainly the future of genitourinary regenerative medicine.

Phosphorylated PAMAM dendrimers: an analog of dentin non-collagenous proteins, enhancing the osteo/odontogenic differentiation of dental pulp stem cells

OBJECTIVES

Polyamidoamine (PAMAM) dendrimers have well-defined structures, with monodispersity and easily modified surface groups, and they have broad applications in biomedicine. In this study, phosphorylated PAMAM (P-PAMAM) dendrimers were synthesized based on the idea of mimicking the phosphorylated proteins of dentin non-collagenous proteins (DNCP). Then, proliferation and osteo/odontogenic differentiation effects of P-PAMAM on dental pulp stem cells (DPSCs) were investigated and were compared with DNCP.

MATERIALS AND METHODS

P-PAMAM was synthesized via the Mannich-type reaction. DNCP were extracted directly from human dentin with ethylenediaminetetraacetic acid (EDTA) solution. Then, the conditioned medium of P-PAMAM and DNCP were prepared respectively and applied to DPSCs. Proliferation of P-PAMAM was investigated with CCK-8, flow cytometry, and EdU test. Osteo/odontogenic differentiation of P-PAMAM was analyzed using alkaline phosphatase activity and staining, RT-PCR, western blot, alizarin red staining, and immunofluorescence staining.

RESULTS

Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance revealed that PAMAM were successfully phosphorylated. Western blot verified that the extracted DNCP contained dentin-related proteins DSPP, OPN, and BMP2. In cell proliferation, there was no apparent difference between P-PAMAM, DNCP, and Control groups (P > 0.05). P-PAMAM and DNCP upregulated related genes and proteins expression (DSPP/DSPP, COL-1/COL-1, ALP/ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN) and matrix mineralization. Still, the potential was lower than that of DNCP (P < 0.05).

CONCLUSIONS

P-PAMAM dendrimers, as a biomimetic analog of DNCP, promote osteo/odontogenic differentiation of DPSCs without influencing their proliferation at a low concentration.

CLINICAL RELEVANCE

This preliminary study about P-PAMAM dendrimers is expected to provide a more convenient bioactive macromolecular material for the regeneration of the pulp-dentin complex.

Stem Cells from Human Exfoliated Deciduous Teeth (SHEDs) and Dental Pulp Stem Cells (DPSCs) Display a Similar Profile with Pericytes

Background

Pericytes play an important role in forming functional blood vessels and establishing stable and effective microcirculation, which is crucial for vascular tissue engineering. The slow ex vivo expansion rate, limited proliferative capacity, and variability of tissue-specific phenotypes would hinder experimental studies and clinical translation of primary pericytes. In this study, the angiogenic and pericyte functions of stem cells from human exfoliated deciduous teeth (SHEDs) and postnatal human dental pulp stem cells (DPSCs) were investigated.

Methods

Osteogenic and adipogenic induction assays were performed to evaluate the mesenchymal potential of SHEDs, DPSCs, and pericytes. An in vitro Matrigel angiogenesis assay was conducted to reveal the ability of SHEDs, DPSCs, and pericytes to stabilize vascular-like structures. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed to evaluate mRNA expression. Flow cytometry, western blotting, and immunostaining were used to assess the protein expression. Wound healing and transwell assays were performed to evaluate the migration ability of SHEDs, DPSCs, and pericytes.

Results

The osteogenic and adipogenic induction assays showed that SHEDs, DPSCs, and pericytes exhibited similar stem cell characteristics. The mRNA expression levels of PDGFR-β, α-SMA, NG2, and DEMSIN in SHEDs and DPSCs cultured in EC medium were significantly higher than those in the control groups on day 7 (P < 0.05), but significantly higher than those in the pericytes group on day 14 (P < 0.05). Flow cytometry showed that high proportions of SHEDs and DPSCs were positive for various pericyte markers on day 7. The DPSCs, SHEDs, and pericytes displayed strong migration ability; however, there was no significant difference among the groups (P > 0.05).

Conclusion

The SHEDs and DPSCs display a profile similar to that of pericytes. Our study lays a solid theoretical foundation for the clinical use of dental pulp stem cells as a potential candidate to replace pericytes.

Inhibition of LIM kinase reduces contraction and proliferation in bladder smooth muscle

Overactive bladder (OAB) is the most bothersome symptom in lower urinary tract symptoms (LUTS). Current pharmacologic treatment aims to inhibit detrusor contraction; however, shows unsatisfied efficacy and high discontinuation rate. LIM kinases (LIMKs) promote smooth muscle contraction in the prostate; however, their function in the bladder smooth muscle remains unclear. Here, we studied effects of the LIMK inhibitors on bladder smooth muscle contraction and proliferation both in vitro and in vivo experiments. Bladder expressions of LIMKs are elevated in OAB rat detrusor tissues. Two LIMK inhibitors, SR7826 and LIMKi3, inhibit contraction of human detrusor strip, and cause actin filament breakdown, as well as cell proliferation reduction in cultured human bladder smooth muscle cells (HBSMCs), paralleled by reduced cofilin phosphorylation. Silencing of LIMK1 and LIMK2 in HBSMCs resulted in breakdown of actin filaments and decreased cell proliferation. Treatment with SR7826 or LIMKi3 decreased micturition frequency and bladder detrusor hypertrophy in rats with bladder outlet obstruction. Our study suggests that LIMKs may promote contraction and proliferation in the bladder smooth muscle, which could be inhibited by small molecule LIMK inhibitors. LIMK inhibitors could be a potential therapeutic strategy for OAB- related LUTS.

Dental-Derived Mesenchymal Stem Cells: State of the Art

Mesenchymal stem cells (MSCs) could be identified in mammalian teeth. Currently, dental-derived MSCs (DMSCs) has become a collective term for all the MSCs isolated from dental pulp, periodontal ligament, dental follicle, apical papilla, and even gingiva. These DMSCs possess similar multipotent potential as bone marrow-derived MSCs, including differentiation into cells that have the characteristics of odontoblasts, cementoblasts, osteoblasts, chondrocytes, myocytes, epithelial cells, neural cells, hepatocytes, and adipocytes. Besides, DMSCs also have powerful immunomodulatory functions, which enable them to orchestrate the surrounding immune microenvironment. These properties enable DMSCs to have a promising approach in injury repair, tissue regeneration, and treatment of various diseases. This review outlines the most recent advances in DMSCs' functions and applications and enlightens how these advances are paving the path for DMSC-based therapies.

Multidifferentiation potential of dental-derived stem cells

Tooth-related diseases and tooth loss are widespread and are a major public health issue. The loss of teeth can affect chewing, speech, appearance and even psychology. Therefore, the science of tooth regeneration has emerged, and attention has focused on tooth regeneration based on the principles of tooth development and stem cells combined with tissue engineering technology. As undifferentiated stem cells in normal tooth tissues, dental mesenchymal stem cells (DMSCs), which are a desirable source of autologous stem cells, play a significant role in tooth regeneration. Researchers hope to reconstruct the complete tooth tissues with normal functions and vascularization by utilizing the odontogenic differentiation potential of DMSCs. Moreover, DMSCs also have the ability to differentiate towards cells of other tissue types due to their multipotency. This review focuses on the multipotential capacity of DMSCs to differentiate into various tissues, such as bone, cartilage, tendon, vessels, neural tissues, muscle-like tissues, hepatic-like tissues, eye tissues and glands and the influence of various regulatory factors, such as non-coding RNAs, signaling pathways, inflammation, aging and exosomes, on the odontogenic/osteogenic differentiation of DMSCs in tooth regeneration. The application of DMSCs in regenerative medicine and tissue engineering will be improved if the differentiation characteristics of DMSCs can be fully utilized, and the factors that regulate their differentiation can be well controlled.

DPSCs treated by TGF-β1 regulate angiogenic sprouting of three-dimensionally co-cultured HUVECs and DPSCs through VEGF-Ang-Tie2 signaling

Background

Maintaining the stability and maturation of blood vessels is of paramount importance for the vessels to carry out their physiological function. Smooth muscle cells (SMCs), pericytes, and mesenchymal stem cells (MSCs) are involved in the maturation process of the newly formed vessels. The aim of this study was to investigate whether transforming growth factor beta 1 (TGF-β1) treatment could enhance pericyte-like properties of dental pulp stem cells (DPSCs) and how TGF-β1-treated DPSCs for 7 days (T-DPSCs) stabilize the newly formed blood vessels.

Methods

We utilized TGF-β1 to treat DPSCs for 1, 3, 5, and 7 days. Western blotting and immunofluorescence were used to analyze the expression of SMC markers. Functional contraction assay was conducted to assess the contractility of T-DPSCs. The effects of T-DPSC-conditioned media (T-DPSC-CM) on human umbilical vein endothelial cell (HUVEC) proliferation and migration were examined by MTT, wound healing, and trans-well migration assay. Most importantly, in vitro 3D co-culture spheroidal sprouting assay was used to investigate the regulating role of vascular endothelial growth factor (VEGF)-angiopoietin (Ang)-Tie2 signaling on angiogenic sprouting in 3D co-cultured spheroids of HUVECs and T-DPSCs. Angiopoietin 2 (Ang2) and VEGF were used to treat the co-cultured spheroids to explore their roles in angiogenic sprouting. Inhibitors for Tie2 and VEGFR2 were used to block Ang1/Tie2 and VFGF/VEGFR2 signaling.

Results

Western blotting and immunofluorescence showed that the expression of SMC-specific markers (α-SMA and SM22α) were significantly increased after treatment with TGF-β1. Contractility of T-DPSCs was greater compared with that of DPSCs. T-DPSC-CM inhibited HUVEC migration. In vitro sprouting assay demonstrated that T-DPSCs enclosed HUVECs, resembling pericyte-like cells. Compared to co-culture with DPSCs, a smaller number of HUVEC sprouting was observed when co-cultured with T-DPSCs. VEGF and Ang2 co-stimulation significantly enhanced sprouting in HUVEC and T-DPSC co-culture spheroids, whereas VEGF or Ang2 alone exerted insignificant effects on HUVEC sprouting. Blocking Tie2 signaling reversed the sprouting inhibition by T-DPSCs, while blocking VEGF receptor (VEGFR) signaling boosted the sprouting inhibition by T-DPSCs.

Conclusions

This study revealed that TGF-β1 can induce DPSC differentiation into functional pericyte-like cells. T-DPSCs maintain vessel stability through Ang1/Tie2 and VEGF/VEGFR2 signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02349-y.

Human Dental Pulp-Derived Mesenchymal Stem Cell Potential to Differentiate into Smooth Muscle-Like Cells In Vitro

Previous studies have shown that mesenchymal stem cells (MSCs) derived from various tissue sources can be differentiated into smooth muscle-like cells (SMLCs) in vitro. In this paper, dental pulp-derived mesenchymal stem cells (DPSCs) were evaluated for their differentiation ability towards smooth muscle-like cells (SMLCs) under the effect of widely used cytokines (TGF-β1 and PDGF-BB) with special focus on different culturing environments. For this purpose, both the commercially used culturing plates (Norm-c) and 0.1% gelatin-precoated (Gel-c) plates were used. Isolated cells displayed plastic adherence, pluripotency and cell surface marker profiling, and adipogenic and osteogenic differentiation potential with lineage specific marker expression. Differentiated cells induced under different culturing plates showed successful differentiation into SMLCs by positively expressing smooth muscle cell (SMC) specific markers both at the mRNA and protein levels. Gelatin coating could substantially enhance DPSC differentiation potential than Norm-c-induced cells. However, the absence of mature marker MHY-11 by immunostaining results from all treatment groups further indicated the development of immature and synthetic SMLCs. Finally, it was concluded that DPSC differentiation ability into SMLCs can be enhanced under cytokine treatment as well as by altering the cellular niche by precoating the culturing plates with suitable substrates. However, to get fully functional, contractile, and mature SMLCs, still many different cytokine cocktail combinations and more suitable coating substrates will be needed.

Insight into the Role of Dental Pulp Stem Cells in Regenerative Therapy

Mesenchymal stem cells (MSCs) have the capacity for self-renewal and multilineage differentiation potential, and are considered a promising cell population for cell-based therapy and tissue regeneration. MSCs are isolated from various organs including dental pulp, which originates from cranial neural crest-derived ectomesenchyme. Recently, dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs) have been isolated from dental pulp tissue of adult permanent teeth and deciduous teeth, respectively. Because of their MSC-like characteristics such as high growth capacity, multipotency, expression of MSC-related markers, and immunomodulatory effects, they are suggested to be an important cell source for tissue regeneration. Here, we review the features of these cells, their potential to regenerate damaged tissues, and the recently acquired understanding of their potential for clinical application in regenerative medicine.

Detrusor bioengineering using a cell-enriched compressed collagen hydrogel

OBJECTIVE

The gold standard for bladder regeneration in end-stage bladder disease is the use of intestinal tissue, which is however associated with significant long-term complications. Our study aims to bioengineer functional detrusor muscle combining bladder smooth muscle cells (SMC) and SMC-like adipose-derived stem cells (pADSC) in compressed collagen (CC) hydrogels and to investigate biocompatibility and tissue regeneration of such detrusor-equivalents in a rat detrusorectomy model.

METHODS

Compressed collagen hydrogels seeded with 1 × 10⁶ or 4 × 10⁶ SMC alone or in combination with pADSC in a 1:1 ratio were investigated. Morphology, phenotype, and viability as well as proteomic secretome analysis were assessed in the 1:1 co-cultures and the respective monocultures. The hydrogels were implanted into rat bladders after partial detrusorectomy. Bladders were harvested 8 weeks after transplantation, and assessed for tissue morphology, detrusor regeneration, neo-vascularization and -innervation.

RESULTS

Co-cultured cells exhibited native SMC morphology, high viability and proliferated to form microtissues in vitro. The pro-angiogenic factors angiogenin, vascular endothelial growth factor (VEGF)-A and -D were increased in the secretome of the pADSC samples. After 8 weeks of in vivo, the regenerated bladder wall showed a multilayered structure containing all bladder wall components. The overall performance of the bladder wall regeneration of CC seeded with 4 × 10⁶ cells was significantly better than with 1 × 10⁶ cells and the combination SMC:pADCS performed slightly better than SMC alone.

CONCLUSION

Compressed collagen possesses an adequate regenerative potential to promote regeneration of bladder wall tissue in vivo. Seeded with a combination of pADSC and SMC this may well be the first step towards a functional bladder reconstruction especially in patients suffering of end-stage bladder diseases.

Efficient smooth muscle cell differentiation of iPS cells on curcumin-incorporated chitosan/collagen/polyvinyl-alcohol nanofibers

Bladder dysfunction is one of the most common diseases that occur for a number of reasons and the current treatment modalities do not improve much in its recovery process. Tissue engineering in the last two decades has given great hope for the treatment of these disorders. In this study, a composite nanofibrous scaffold was fabricated from chitosan, collagen, and polyvinyl-alcohol polymer blend while curcumin incorporated in scaffold fibers. The scaffold supportive functions from smooth muscle cell differentiation were studied when human-induced pluripotent stem cells were cultured on the scaffolds under differentiation medium. Biocompatibility of the fabricated scaffold increased significantly by incorporating curcumin in the scaffold fibers, where protein adsorption, cell attachment, and viability were increased in the nanofiber/curcumin group compared with the other groups. In addition, the expression level of smooth muscle cell-related genes, including alpha-smooth muscle actin (αSMA), smooth muscle 22 alpha (SM-22a), Caldesmon1, and Calponin1in the stem cells upregulated while cultured in the presence of curcumin, but this increase was significantly improved while cells cultured on the nanofibers/curcumin. In addition, αSMA protein in the cells cultured on the nanofibers/curcumin expressed significantly higher than those cells cultured on the nanofibers without curcumin. It can be concluded that smooth muscle cell differentiation of the induced pluripotent stem cells promoted by curcumin and this promotion was synergistically improved while curcumin incorporated in the nanofibers.

Pulp stem cells derived from human permanent and deciduous teeth: Biological characteristics and therapeutic applications

Human pulp stem cells (PSCs) include dental pulp stem cells (DPSCs) isolated from dental pulp tissues of human extracted permanent teeth and stem cells from human exfoliated deciduous teeth (SHED). Depending on their multipotency and sensitivity to local paracrine activity, DPSCs and SHED exert therapeutic applications at multiple levels beyond the scope of the stomatognathic system. This review is specifically concentrated on PSC-updated biological characteristics and their promising therapeutic applications in (pre)clinical practice. Biologically, distinguished from conventional mesenchymal stem cell markers in vitro, NG2, Gli1, and Celsr1 have been evidenced as PSC markers in vivo. Both perivascular cells and glial cells account for PSC origin. Therapeutically, endodontic regeneration is where PSCs hold the most promises, attributable of PSCs' robust angiogenic, neurogenic, and odontogenic capabilities. More recently, the interplay between cell homing and liberated growth factors from dentin matrix has endowed a novel approach for pulp-dentin complex regeneration. In addition, PSC transplantation for extraoral tissue repair and regeneration has achieved immense progress, following their multipotential differentiation and paracrine mechanism. Accordingly, PSC banking is undergoing extensively with the intent of advancing tissue engineering, disease remodeling, and (pre)clinical treatments.

Application of Adult and Pluripotent Stem Cells in Interstitial Cystitis/Bladder Pain Syndrome Therapy: Methods and Perspectives

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a multifactorial, chronic disease without definite etiology characterized by bladder-related pelvic pain. IC/BPS is associated with pain that negatively affects the quality of life. There are various therapeutic approaches against IC/BPS. However, no efficient therapeutic agent against IC/BPS has been discovered yet. Urothelium dysfunction is one of the key factors of IC/BPS-related pathogenicity. Stem cells, including adult stem cells (ASCs) and pluripotent stem cells (PSCs), such as embryonic stem cells (ESCs) and induced PSCs (iPSCs), possess the abilities of self-renewal, proliferation, and differentiation into various cell types, including urothelial and other bladder cells. Therefore, stem cells are considered robust candidates for bladder regeneration. This review provides a brief overview of the etiology, pathophysiology, diagnosis, and treatment of IC/BPS as well as a summary of ASCs and PSCs. The potential of ASCs and PSCs in bladder regeneration via differentiation into bladder cells or direct transplantation into the bladder and the possible applications in IC/BPS therapy are described in detail. A better understanding of current studies on stem cells and bladder regeneration will allow further improvement in the approaches of stem cell applications for highly efficient IC/BPS therapy.

Dental Pulp Stem Cells: Advances to Applications

Dental pulp stem cells (DPSCs) have a high capacity for differentiation and the ability to regenerate a dentin/pulp-like complex. Numerous studies have provided evidence of DPSCs’ differentiation capacity, such as in neurogenesis, adipogenesis, osteogenesis, chondrogenesis, angiogenesis, and dentinogenesis. The molecular mechanisms and functions of DPSCs’ differentiation process are affected by growth factors and scaffolds. For example, growth factors such as basic fibroblast growth factor (bFGF), transforming growth factor-β (TGF-β), nerve growth factor (NGF), platelet-derived growth factor (PDGF), and bone morphogenic proteins (BMPs) influence DPSC fate, including in differentiation, cell proliferation, and wound healing. In addition, several types of scaffolds, such as collagen, hydrogel, decellularized bioscaffold, and nanofibrous spongy microspheres, have been used to characterize DPSC cellular attachment, migration, proliferation, differentiation, and functions. An appropriate combination of growth factors and scaffolds can enhance the differentiation capacity of DPSCs, in terms of optimizing not only dental-related expression but also dental pulp morphology. For a cell-based clinical approach, focus has been placed on the tissue engineering triad [cells/bioactive molecules (growth factors)/scaffolds] to characterize DPSCs. It is clear that a deep understanding of the mechanisms of stem cells, including their aging, self-renewal, microenvironmental homeostasis, and differentiation correlated with cell activity, the energy for which is provided from mitochondria, should provide new approaches for DPSC research and therapeutics. Mitochondrial functions and dynamics are related to the direction of stem cell differentiation, including glycolysis, oxidative phosphorylation, mitochondrial metabolism, mitochondrial transcription factor A (TFAM), mitochondrial elongation, and mitochondrial fusion and fission proteins. This review summarizes the effects of major growth factors and scaffolds for regenerating dentin/pulp-like complexes, as well as elucidating mitochondrial properties of DPSCs for the development of advanced applications research.

Differentiation potential of different regions-derived same donor human Wharton's jelly mesenchymal stem cells into functional smooth muscle-like cells

The present study evaluates the transdifferentiation potential of different region-derived same donor Wharton's jelly MSCs (WJMSCs) into functional smooth muscle-like cells (SMLCs). All regions showed baseline expression for early smooth muscle cell (SMC) markers (αSMA and SM22-α) whereas mid marker CALPONIN gradually reduced during in vitro culture expansion and late marker myosin heavy chain type-11 (MHY-11) was completely absent. Furthermore, WJMSCs were induced to SMLCs using DMEM containing 10% FBS supplemented with different concentrations/combinations of TGF-β1 and PDGF-BB under normoxia (20% O₂) condition. Three treatment groups namely group A: 2.5 ng/ml TGF-β1, group B: 5 ng/ml PDGF-BB and group C: 2.5 ng/ml TGF-β1 + 5 ng/ml PDGF-BB were used for the induction of WJMSCs into SMLCs. Cells were evaluated for SMC-specific marker expression at different time intervals. Finally, selection of the SMC-specific highly potent region along with the most suitable treatment group was done on the basis of highest outcome in terms of SMC-specific marker expression and functional competence of transdifferentiated cells. Among all regions, baby region-derived WJMSCs (B-WJMSCs) exhibited highest SMC marker expression and functional ability. To mimic the in vivo physiological conditions, hypoxic conditions (3% O₂) were used to evaluate the effect of low oxygen on the SMLC differentiation potential of selected WJMSCs using previously used same parameters. Annexin-V assay was performed to check the effect of cytokines and different oxygen concentrations, which revealed no significant differences. It was concluded that different induction conditions have different but positive effects on the functional SMLC differentiation ability of WJMSCs.

Tissue Engineering in Pediatric Bladder Reconstruction-The Road to Success

Several congenital disorders can cause end stage bladder disease and possibly renal damage in children. The current gold standard therapy is enterocystoplasty, a bladder augmentation using an intestinal segment. However, the use of bowel tissue is associated with numerous complications such as metabolic disturbance, stone formation, urine leakage, chronic infections, and malignancy. Urinary diversions using engineered bladder tissue would obviate the need for bowel for bladder reconstruction. Despite impressive progress in the field of bladder tissue engineering over the past decades, the successful transfer of the approach into clinical routine still represents a major challenge. In this review, we discuss major achievements and challenges in bladder tissue regeneration with a focus on different strategies to overcome the obstacles and to meet the need for living functional tissue replacements with a good growth potential and a long life span matching the pediatric population.

Wnt-GSK3β/β-Catenin Regulates the Differentiation of Dental Pulp Stem Cells into Bladder Smooth Muscle Cells

Smooth muscle cell- (SMC-) based tissue engineering provides a promising therapeutic strategy for SMC-related disorders. It has been demonstrated that human dental pulp stem cells (DPSCs) possess the potential to differentiate into mature bladder SMCs by induction with condition medium (CM) from bladder SMC culture, in combination with the transforming growth factor-β1 (TGF-β1). However, the molecular mechanism of SMC differentiation from DPSCs has not been fully uncovered. The canonical Wnt signaling (also known as Wnt/β-catenin) pathway plays an essential role in stem cell fate decision. The aim of this study is to explore the regulation via GSK3β and associated downstream effectors for SMC differentiation from DPSCs. We characterized one of our DPSC clones with the best proliferation and differentiation abilities. This stem cell clone has shown the capacity to generate a smooth muscle layer-like phenotype after an extended differentiation duration using the SMC induction protocol we established before. We further found that Wnt-GSK3β/β-catenin signaling is involved in the process of SMC differentiation from DPSCs, as well as a serial of growth factors, including TGF-β1, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor-homodimer polypeptide of B chain (BB) (PDGF-BB), and vascular endothelial growth factor (VEGF). Pharmacological inhibition on the canonical Wnt-GSK3β/β-catenin pathway significantly downregulated GSK3β phosphorylation and β-catenin activation, which in consequence reduced the augmented expression of the growth factors (including TGF-β1, HGF, PDGF-BB, and VEGF) as well as SMC markers (especially myosin) at a late stage of SMC differentiation. These results suggest that the canonical Wnt-GSK3β/β-catenin pathway contributes to DPSC differentiation into mature SMCs through the coordination of different growth factors.

Smooth muscle cell differentiation from rabbit amniotic cells

Amniotic fluid (AF) is the liquid layer that provides mechanical support and allows movement of the fetus during embryogenesis. Mesenchymal stem cells (MSCs), which have differentiation capacity, are also found in AF-derived cells at a low ratio. Smooth muscle cells (SMCs) play an important role in organ function and are frequently used in tissue engineering. We examined the differentiation of AF-derived MSCs (AMSCs) into SMCs. AMSCs were sorted from cultured amniotic cells and differentiated into SMCs using differentiation agents, including platelet-derived growth factor BB (PDGF-BB) and tumor growth factor β (TGF-β). Characterization of differentiated SMCs was confirmed morphologically, molecularly (via quantitative polymerase chain reaction [qPCR] and immunocytochemistry [ICC]), and functionally (using a contractile assay and fluo-4 calcium signaling assay). Poly(lactide-co-glycolide) (PLGA) scaffolds were fabricated, and the attachment capacity of AMSCs was assessed via scanning electron microscopy. AMSCs were successfully differentiated into SMCs. Our results indicate that AMSCs change their morphology and exhibit increased expression of ACTA2 and MYH11, which was confirmed via qPCR and ICC. Furthermore, functional experiments revealed that differentiated SMCs had both contraction ability and increased Ca² concentration in the cytoplasm. Finally, PLGA scaffolds were prepared and AMSCs were successfully planted onto the scaffolds. The AMSCs fully differentiated into functional SMCs, and the PLGA polymer is a suitable scaffold material for AMSCs. With further clinical trials, AF-derived MSC-based SMC engineering may become a highly efficient treatment option.

Therapeutic effect of dental pulp stem cell transplantation on a rat model of radioactivity-induced esophageal injury

Dental pulp stem cell (DPSC) transplantation has been demonstrated to promote the regeneration and repair of tissues and organs and is a potentially effective treatment for radioactive esophageal injury. In this study, to explore the therapeutic effects of DPSCs on acute radiation-induced esophageal injury, DPSCs were cultured and transplanted into rats with acute radioactive esophageal injuries induced by radioactive ¹²⁵I seeds in vivo. In the injured esophagus, PKH26-labeled DPSCs co-localized with PCNA, CK14, CD71, and integrin α6, and the expression levels of these four makers of esophageal stem cells were significantly increased. After DPSC transplantation, the injured esophagus exhibited a greater thickness. In addition, the esophageal function and inflammation recovered faster. The results demonstrated that transplanted DPSCs, which trans-differentiated into esophageal stem cells in vivo, could repair the damaged esophageal tissue.

Dental Mesenchymal Stem Cell-Based Translational Regenerative Dentistry: From Artificial to Biological Replacement

Dentistry is a continuously changing field that has witnessed much advancement in the past century. Prosthodontics is that branch of dentistry that deals with replacing missing teeth using either fixed or removable appliances in an attempt to simulate natural tooth function. Although such "replacement therapies" appear to be easy and economic they fall short of ever coming close to their natural counterparts. Complications that arise often lead to failures and frequent repairs of such devices which seldom allow true physiological function of dental and oral-maxillofacial tissues. Such factors can critically affect the quality of life of an individual. The market for dental implants is continuously growing with huge economic revenues. Unfortunately, such treatments are again associated with frequent problems such as peri-implantitis resulting in an eventual loss or replacement of implants. This is particularly influential for patients having co-morbid diseases such as diabetes or osteoporosis and in association with smoking and other conditions that undoubtedly affect the final treatment outcome. The advent of tissue engineering and regenerative medicine therapies along with the enormous strides taken in their associated interdisciplinary fields such as stem cell therapy, biomaterial development, and others may open arenas to enhancing tissue regeneration via designing and construction of patient-specific biological and/or biomimetic substitutes. This review will overview current strategies in regenerative dentistry while overviewing key roles of dental mesenchymal stem cells particularly those of the dental pulp, until paving the way to precision/translational regenerative medicine therapies for future clinical use.

1,25-Dihydroxyvitamin D3 stimulates odontoblastic differentiation of human dental pulp-stem cells in vitro

BACKGROUND

1,25-Dihydroxyvitamin D₃ (1,25-OH D₃) plays an important role in mineralized tissue metabolism, including teeth. However, few studies have addressed its role in odontoblastic differentiation of human dental pulp-stem cells (hDPSCs).

AIM

This study aimed to understand the influence of various concentrations of 1,25-OH D₃ on the proliferation capacity and early dentinogenesis responses of hDPSCs.

MATERIALS AND METHODS

hDPSCs were obtained from the impacted third molar teeth. Monolayer cultured cells were incubated with a differentiation medium containing different concentrations of 1,25-OH D₃ (0.001, 0.01, and 0.1 µM). All groups were evaluated by S-phase rate [immunohistochemical (IHC) bromodeoxyuridine (BrdU) staining], STRO-1 and dentin sialoprotein (DSP)+ levels (IHC), and alkaline phosphatase (ALP, enzyme-linked immunosorbent assay (ELISA)) levels.

RESULTS

The number of cells that entered the S-phase was determined to be the highest and lowest in the control and 0.001 µM 1,25-OH D₃ groups, respectively. The 0.1 µM vitamin D₃ group had the highest increase in DSP+ levels. The highest Stro-1 levels were detected in the control and 0.1 µM 1,25-OH D₃ groups, respectively. The 0.1 µM 1,25-OH D₃ induced a mild increase in ALP activity.

CONCLUSIONS

This study demonstrated that 1,25-OH D₃ stimulated odontoblastic differentiation of hDPSCs in vitro in a dose-dependent manner. The high DSP + cell number and a mild increase in ALP activity suggest that DPSCs treated with 0.1 μM 1,25-OH D₃ are in the later stage of odontoblastic differentiation. The results confirm that 1,25-OH D₃-added cocktail medium provides a sufficient microenvironment for the odontoblastic differentiation of hDPSCs in vitro.

IFN-γ regulates human dental pulp stem cells behavior via NF-κB and MAPK signaling

During caries, dental pulp expresses a range of pro-inflammatory cytokines in response to the infectious challenge. Interferon gamma (IFN-γ) is a dimerized soluble cytokine, which is critical for immune responses. Previous study has demonstrated that IFN-γ at relative high concentration (100 ng/mL) treatment improved the impaired dentinogenic and immunosuppressive regulatory functions of disease-derived dental pulp stem cells (DPSCs). However, little is known about the regulatory effects of IFN-γ at relative low concentration on healthy DPSC behavior (including proliferation, migration, and multiple-potential differentiation). Here we demonstrate that IFN-γ at relatively low concentrations (0.5 ng/mL) promoted the proliferation and migration of DPSCs, but abrogated odonto/osteogenic differentiation. Additionally, we identified that NF-κB and MAPK signaling pathways are both involved in the process of IFN-γ-regulated odonto/osteogenic differentiation of DPSCs. DPSCs treated with IFN-γ and supplemented with pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) or SB203580 (a MAPK inhibitor) showed significantly improved potential for odonto/osteogenic differentiation of DPSCs both in vivo and in vitro. These data provide important insight into the regulatory effects of IFN-γ on the biological behavior of DPSCs and indicate a promising therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment.

Stem Cells in Functional Bladder Engineering

Conditions impairing bladder function in children and adults, such as myelomeningocele, posterior urethral valves, bladder exstrophy or spinal cord injury, often need urinary diversion or augmentation cystoplasty as when untreated they may cause severe bladder dysfunction and kidney failure. Currently, the gold standard therapy of end-stage bladder disease refractory to conservative management is enterocystoplasty, a surgical enlargement of the bladder with intestinal tissue. Despite providing functional improvement, enterocystoplasty is associated with significant long-term complications, such as recurrent urinary tract infections, metabolic abnormalities, stone formation, and malignancies. Therefore, there is a strong clinical need for alternative therapies for these reconstructive procedures, of which stem cell-based tissue engineering (TE) is considered to be the most promising future strategy. This review is focused on the recent progress in bladder stem cell research and therapy and the challenges that remain for the development of a functional bladder wall.

The Regulatory Effects of Long Noncoding RNA-ANCR on Dental Tissue-Derived Stem Cells

Long noncoding RNAs (lncRNA) have been recognized as important regulators in diverse biological processes, such as transcriptional regulation, stem cell proliferation, and differentiation. Previous study has demonstrated that lncRNA-ANCR (antidifferentiation ncRNA) plays a key role in regulating the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). However, little is known about the role of ANCR in regulating other types of dental tissue-derived stem cells (DTSCs) behaviours (including proliferation and multiple-potential of differentiation). In this study, we investigated the regulatory effects of lncRNA-ANCR on the proliferation and differentiation (including osteogenic, adipogenic, and neurogenic differentiation) of DTSCs, including dental pulp stem cells (DPSCs), PDLSCs, and stem cells from the apical papilla (SCAP) by downregulation of lncRNA-ANCR. We found that downregulation of ANCR exerted little effect on proliferation of DPSCs and SCAP but promoted the osteogenic, adipogenic, and neurogenic differentiation of DTSCs. These data provide an insight into the regulatory effects of long noncoding RNA-ANCR on DTSCs and indicate that ANCR is a very important regulatory factor in stem cell differentiation.

Dental and Nondental Stem Cell Based Regeneration of the Craniofacial Region: A Tissue Based Approach

Craniofacial reconstruction may be a necessary treatment for those who have been affected by trauma, disease, or pathological developmental conditions. The use of stem cell therapy and tissue engineering shows massive potential as a future treatment modality. Currently in the literature, there is a wide variety of published experimental studies utilising the different stem cell types available and the plethora of available scaffold materials. This review investigates different stem cell sources and their unique characteristics to suggest an ideal cell source for regeneration of individual craniofacial tissues. At present, understanding and clinical applications of stem cell therapy remain in their infancy with numerous challenges to overcome. In spite of this, the field displays immense capacity and will no doubt be utilised in future clinical treatments of craniofacial regeneration.