Platelet-Derived Growth Factor Receptor Alpha as a Marker of Mesenchymal Stem Cells in Development and Stem Cell Biology

Three decades on, the mesenchymal stem cells (MSCs) have been intensively researched on the bench top and used clinically. However, ambiguity still exists in regard to their anatomical locations, identities, functions, and extent of their differentiative abilities. One of the major impediments in the quest of the MSC research has been lack of appropriate in vivo markers. In recent years, this obstacle has been resolved to some degree as PDGFRα emerges as an important mesenchymal stem cell marker. Accumulating lines of evidence are showing that the PDGFRα+ cells reside in the perivascular locations of many adult interstitium and fulfil the classic concepts of MSCs in vitro and in vivo. PDGFRα has long been recognised for its roles in the mesoderm formation and connective tissue development during the embryogenesis. Current review describes the lines of evidence regarding the role of PDGFRα in morphogenesis and differentiation and its implications for MSC biology

Regenerative approaches in oral medicine

Stem cells are undifferentiated cells, which possess self-renewal properties and can produce specialized cells of multiple lineages. In addition to other stem cells from various anatomical locations within the maxillofacial complex, the oral cavity harbours both epithelial and mesenchymal stem cells, each suited to approaches for treating or managing a variety of specific conditions encountered in routine clinical oral medicine practice. This chapter focusses on stem cell and regenerative medicine approaches related to oral pathology and oral medicine with particular attention paid to oral mucosal diseases, salivary gland disorders, craniofacial and temporomandibular joint disorders, and orofacial pain conditions. The potential roles of stem cells in highlighting the pathogenesis of these conditions in addition to regenerative strategies for their management are outlined. The role of bioprinting as a potential therapeutic approach for both soft and hard tissue defects is discussed. Finally, the limitations of current approaches to regenerative medicine underpinned by imperfect and incomplete understanding of stem cell niches and their properties are summarized

Single-cell expression profiling reveals dynamic flux of cardiac stromal, vascular and immune cells in health and injury

Besides cardiomyocytes (CM), the heart contains numerous interstitial cell types which play key roles in heart repair, regeneration and disease, including fibroblast, vascular and immune cells. However, a comprehensive understanding of this interactive cell community is lacking. We performed single-cell RNA-sequencing of the total non-CM fraction and enriched (Pdgfra-GFP+) fibroblast lineage cells from murine hearts at days 3 and 7 post-sham or myocardial infarction (MI) surgery. Clustering of >30,000 single cells identified >30 populations representing nine cell lineages, including a previously undescribed fibroblast lineage trajectory present in both sham and MI hearts leading to a uniquely activated cell state defined in part by a strong anti-WNT transcriptome signature. We also uncovered novel myofibroblast subtypes expressing either pro- fibrotic or anti-fibrotic signatures. Our data highlight non-linear dynamics in myeloid and fibroblast lineages after cardiac injury, and provide an entry point for deeper analysis of cardiac homeostasis, inflammation, fibrosis, repair and regeneration