Limited Adipogenic Differentiation Potential of Human Dental Pulp Stem Cells Compared to Human Bone Marrow Stem Cells.

Bone marrow and teeth contain mesenchymal stem cells (MSCs) that could be used for cell-based regenerative therapies. MSCs from these two tissues represent heterogeneous cell populations with varying degrees of lineage commitment. Although human bone marrow stem cells (hBMSCs) and human dental pulp stem cells (hDPSCs) have been extensively studied, it is not yet fully defined if their adipogenic potential differs.

An unexpected role of neurite outgrowth inhibitor A as regulator of tooth enamel formation.

Neurite outgrowth inhibitor A (Nogo-A) is a major player in neural development and regeneration and the target of clinical trials aiming at promoting the regeneration of the central nervous system upon traumatic and ischemic injury. In this work, we investigated the functions of Nogo-A during tooth development to determine its role in dental physiology and pathology. Using immunohistochemistry and in situ hybridization techniques, we showed that Nogo-A is highly expressed in the developing mouse teeth and, most specifically, in the ameloblasts that are responsible for the formation of enamel.

"Periodontal ligament-on-chip" as a Novel Tool for Studies on the Physiology and Pathology of Periodontal Tissues.

Teeth exert fundamental physiological functions, such as mastication and speech, and are a key feature of oral health that affects life quality. Teeth are anchored to the alveolar bone via the periodontal ligament, which provides stability to the teeth and absorbs mechanical stresses during mastication. Periodontal infection leads to periodontitis, a severe inflammation of the supporting soft tissues that ultimately cause tooth loss.

Extracellular matrix remodelling in dental pulp tissue of carious human teeth through the prism of single-cell RNA sequencing.

Carious lesions are bacteria-caused destructions of the mineralised dental tissues, marked by the simultaneous activation of immune responses and regenerative events within the soft dental pulp tissue. While major molecular players in tooth decay have been uncovered during the past years, a detailed map of the molecular and cellular landscape of the diseased pulp is still missing. In this study we used single-cell RNA sequencing analysis, supplemented with immunostaining, to generate a comprehensive single-cell atlas of the pulp of carious human teeth.

Kidney capsule transplantation of chemically treated embryonic murine tooth germs.

Subcapsular transplantation of developing tissues and organs into the richly vascularized murine kidney provides the necessary trophic support, thus ensuring proper completion of their growth. Here, we provide a protocol for kidney capsule transplantation that allows the full differentiation of embryonic teeth previously exposed to chemicals. We describe steps for dissection and in vitro culture of embryonic teeth, followed by transplantation of tooth germs.

Notch Signaling Pathway in Tooth Shape Variations throughout Evolution.

Evolutionary changes in vertebrates are linked to genetic alterations that often affect tooth crown shape, which is a criterion of speciation events. The Notch pathway is highly conserved between species and controls morphogenetic processes in most developing organs, including teeth. Epithelial loss of the Notch-ligand Jagged1 in developing mouse molars affects the location, size and interconnections of their cusps that lead to minor tooth crown shape modifications convergent to those observed along Muridae evolution.

Nogo-A Regulates the Fate of Human Dental Pulp Stem Cells toward Osteogenic, Adipogenic, and Neurogenic Differentiation.

Human teeth are highly innervated organs that contain a variety of mesenchymal stem cell populations that could be used for cell-based regenerative therapies. Specific molecules are often used in these treatments to favorably modulate the function and fate of stem cells. Nogo-A, a key regulator of neuronal growth and differentiation, is already used in clinical tissue regeneration trials.

Adam10-dependent Notch signaling establishes dental epithelial cell boundaries required for enamel formation.

The disintegrin and metalloproteinase Adam10 is a membrane-bound sheddase that regulates Notch signaling and ensures epidermal integrity. To address the function of Adam10 in the continuously growing incisors, we used Keratin14 ;Adam10 transgenic mice, in which Adam10 is conditionally deleted in the dental epithelium. Keratin14 ;Adam10 mice exhibited severe abnormalities, including defective enamel formation reminiscent of human enamel pathologies.

Exosomes as Carriers for Notch Molecules.

Exosomes are extracellular vesicles involved in cell-to-cell communication as well as extrusion of biological material. Using dental pulp stem cells culture as a model, we hereby describe a method for the packaging of Delta-like 4 (DLL4), a representative Notch ligand, into newly generated exosomes. We then provide methods of analysis to confirm the presence of Notch proteins and transcripts internalization and transport via exosomes.

Editorial - Brothers in arms: regenerative biology and dentistry.

The eCM special issue on Dental Regenerative Biology concentrates on recent key developments that will probably soon lead to significantly improved dental treatments. Progress in the understanding of the biology and technology involved provides exciting new clinical approaches to repairing and regenerating missing or damaged dental tissues. The application of stem cells has the potential to improve tissue regeneration and the use of significantly improved biomaterials can aid dental tissue healing.

Three-Dimensional Culture Systems for Dissecting Notch Signalling in Health and Disease.

Three-dimensional (3D) culture systems opened up new horizons in studying the biology of tissues and organs, modelling various diseases, and screening drugs. Producing accurate in vitro models increases the possibilities for studying molecular control of cell-cell and cell-microenvironment interactions in detail. The Notch signalling is linked to cell fate determination, tissue definition, and maintenance in both physiological and pathological conditions.

Isolation of dental pulp and periodontal cells from human teeth for single-cell RNA sequencing.

Teeth and the surrounding periodontal tissues are affected by many pathologies that compromise their integrity and significantly affect life quality. The study of the main dental tissues, the dental pulp and periodontium, is made arduous by their close association with highly mineralized tissues (dentin, cementum, and alveolar bone). Here we describe a protocol to isolate all cells composing human dental pulp and periodontium for single-cell RNA sequencing analysis.

New Scenarios in Pharmacological Treatments of Head and Neck Squamous Cell Carcinomas.

Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent types of cancer with a lethal outcome in half of the diagnosed cases. Mostly, HNSCC develops in the oral cavity, and its development is associated with tobacco and areca nut/betel quid usage, alcohol consumption, and HPV infection. Oral squamous cell carcinoma, as other head and neck cancers, presents a high degree of intratumor heterogeneity, which makes their treatment difficult, and directly correlates with drug resistance.

The Versatile Roles of Nerve Growth Factor in Neuronal Attraction, Odontoblast Differentiation, and Mineral Deposition in Human Teeth.

Nerve growth factor (NGF) is an important molecule for the development and differentiation of neuronal and non-neuronal cells. Here we analyze by immunohistochemistry the distribution of NGF in the dental pulp mesenchyme of embryonic and functional human teeth. In the dental pulp of both embryonic and healthy functional teeth, NGF is mainly expressed in the odontoblasts that are responsible for dentine formation, while in functional teeth NGF is also expressed in nerve fibers innervating the dental pulp.

Notch signaling in the dynamics of perivascular stem cells and their niches.

The Notch signaling pathway is a fundamental regulator of cell fate determination in homeostasis and regeneration. In this work, we aimed to determine how Notch signaling mediates the interactions between perivascular stem cells and their niches in human dental mesenchymal tissues, both in homeostatic and regenerative conditions. By single cell RNA sequencing analysis, we showed that perivascular cells across the dental pulp and periodontal human tissues all express NOTCH3, and that these cells are important for the response to traumatic injuries in vivo in a transgenic mouse model.

A single-cell atlas of human teeth.

Teeth exert fundamental functions related to mastication and speech. Despite their great biomedical importance, an overall picture of their cellular and molecular composition is still missing. In this study, we have mapped the transcriptional landscape of the various cell populations that compose human teeth at single-cell resolution, and we analyzed in deeper detail their stem cell populations and their microenvironment.

Bioengineered tooth emulation systems for regenerative and pharmacological purposes.

Genetic conditions, traumatic injuries, carious lesions and periodontal diseases are all responsible for dental pathologies. The current clinical approaches are based on the substitution of damaged dental tissues with inert materials, which, however, do not ensure full physiological recovery of the teeth. Different populations of dental mesenchymal stem cells have been isolated from dental tissues and several attempts have already been made at using these stem cells for the regeneration of human dental tissues.

Distinct Expression Patterns of Cxcl12 in Mesenchymal Stem Cell Niches of Intact and Injured Rodent Teeth.

Specific stem cell populations within dental mesenchymal tissues guarantee tooth homeostasis and regeneration throughout life. The decision between renewal and differentiation of stem cells is greatly influenced by interactions with stromal cells and extracellular matrix molecules that form the tissue specific stem cell niches. The chemokine is a general marker of stromal cells and plays fundamental roles in the maintenance, mobilization and migration of stem cells.

Tp63-expressing adult epithelial stem cells cross lineages boundaries revealing latent hairy skin competence.

The formation of hair follicles, a landmark of mammals, requires complex mesenchymal-epithelial interactions and it is commonly believed that embryonic epidermal cells are the only cells that can respond to hair follicle morphogenetic signals in vivo. Here, we demonstrate that epithelial stem cells of non-skin origin (e.g.

Exploiting teeth as a model to study basic features of signaling pathways.

Teeth constitute a classical model for the study of signaling pathways and their roles in mediating interactions between cells and tissues in organ development, homeostasis and regeneration. Rodent teeth are mostly used as experimental models. Rodent molars have proved fundamental in the study of epithelial-mesenchymal interactions and embryonic organ morphogenesis, as well as to faithfully model human diseases affecting dental tissues.

Molecular and Cellular Modelling of Salivary Gland Tumors Open New Landscapes in Diagnosis and Treatment.

Salivary gland tumors are neoplasms affecting the major and minor salivary glands of the oral cavity. Their complex pathological appearance and overlapping morphological features between subtypes, pose major challenges in the identification, classification, and staging of the tumor. Recently developed techniques of three-dimensional culture and organotypic modelling provide useful platforms for the clinical and biological characterization of these malignancies.

Notch in Head and Neck Cancer.

Head and neck cancer is a group of neoplastic diseases affecting the facial, oral, and neck region. It is one of the most common cancers worldwide with an aggressive, invasive evolution. Due to the heterogeneity of the tissues affected, it is particularly challenging to study the molecular mechanisms at the basis of these tumors, and to date we are still lacking accurate targets for prevention and therapy.

Three-Dimensional Imaging and Gene Expression Analysis Upon Enzymatic Isolation of the Tongue Epithelium.

The tongue is a complex organ involved in a variety of functions such as mastication, speech, and taste sensory function. Enzymatic digestion techniques have been developed to allow the dissociation of the epithelium from the connective tissue of the tongue. However, it is not clear if the integrity and three-dimensional architecture of the isolated epithelium is preserved, and, furthermore if this tissue separation technique excludes its contamination from the mesenchymal tissue.