Blocking TGF-β and BMP SMAD-dependent cell differentiation is a master key to expand all kinds of epithelial stem cells

iPSCs derived from esophageal atresia patients reveal SOX2 dysregulation at the anterior foregut stage

A series of well-regulated cellular and molecular events result in the compartmentalization of the anterior foregut into the esophagus and trachea. Disruption of the compartmentalization process leads to esophageal atresia/tracheoesophageal fistula (EA/TEF). The cause of EA/TEF remains largely unknown. Therefore, to mimic the early development of the esophagus and trachea, we differentiated induced pluripotent stem cells (iPSCs) from EA/TEF patients, and iPSCs and embryonic stem cells from healthy individuals into mature three-dimensional esophageal organoids. CXCR4, SOX17 and GATA4 expression was similar in both patient-derived and healthy endodermal cells. The expression of the key transcription factor SOX2 was significantly lower in the patient-derived anterior foregut. We also observed an abnormal expression of NKX2.1 (or NKX2-1) in the patient-derived mature esophageal organoids. At the anterior foregut stage, RNA sequencing revealed the critical genes GSTM1 and RAB37 to be significantly lower in the patient-derived anterior foregut. We therefore hypothesize that a transient dysregulation of SOX2 and the abnormal expression of NKX2.1 in patient-derived cells could be responsible for the abnormal foregut compartmentalization.

Effects of bone morphogenetic proteins on epithelial repair

Epithelial tissue has important functions such as protection, secretion, and sensation. Epithelial damage is involved in various pathological processes. Bone morphogenetic proteins (BMPs) are a class of growth factors with multiple functions. They play important roles in epithelial cells, including in differentiation, proliferation, and migration during the repair of the epithelium. This article reviews the functions and mechanisms of the most profoundly studied BMPs in the process of epithelial damage repair and their clinical significance.

Phenotypic profiling with a living biobank of primary rhabdomyosarcoma unravels disease heterogeneity and AKT sensitivity

Cancer therapy is currently shifting from broadly used cytotoxic drugs to patient-specific precision therapies. Druggable driver oncogenes, identified by molecular analyses, are present in only a subset of patients. Functional profiling of primary tumor cells could circumvent these limitations, but suitable platforms are unavailable for most cancer entities. Here, we describe an in vitro drug profiling platform for rhabdomyosarcoma (RMS), using a living biobank composed of twenty RMS patient-derived xenografts (PDX) for high-throughput drug testing. Optimized in vitro conditions preserve phenotypic and molecular characteristics of primary PDX cells and are compatible with propagation of cells directly isolated from patient tumors. Besides a heterogeneous spectrum of responses of largely patient-specific vulnerabilities, profiling with a large drug library reveals a strong sensitivity towards AKT inhibitors in a subgroup of RMS. Overall, our study highlights the feasibility of in vitro drug profiling of primary RMS for patient-specific treatment selection in a co-clinical setting.

Patient-specific precision medicine approaches are important for future cancer therapies. Here, the authors show that functional drug profiling with Rhabdomyosarcoma cells isolated from PDX and primary patient tumors uncovers patient-specific vulnerabilities.

Genetic Mouse Models and Induced Pluripotent Stem Cells for Studying Tracheal-Esophageal Separation and Esophageal Development

Esophagus and trachea arise from a common origin, the anterior foregut tube. The compartmentalization process of the foregut into the esophagus and trachea is still poorly understood. Esophageal atresia/tracheoesophageal fistula (EA/TEF) is one of the most common gastrointestinal congenital defects with an incidence rate of 1 in 2,500 births. EA/TEF is linked to the disruption of the compartmentalization process of the foregut tube. In EA/TEF patients, other organ anomalies and disorders have also been reported. Over the last two decades, animal models have shown the involvement of multiple signaling pathways and transcription factors in the development of the esophagus and trachea. Use of induced pluripotent stem cells (iPSCs) to understand organogenesis has been a valuable tool for mimicking gastrointestinal and respiratory organs. This review focuses on the signaling mechanisms involved in esophageal development and the use of iPSCs to model and understand it.

Establishment of Primary Transgenic Human Airway Epithelial Cell Cultures to Study Respiratory Virus-Host Interactions

Primary human airway epithelial cell (hAEC) cultures represent a universal platform to propagate respiratory viruses and characterize their host interactions in authentic target cells. To further elucidate specific interactions between human respiratory viruses and important host factors in the airway epithelium, it is important to make hAEC cultures amenable to genetic modification. However, the short and finite lifespan of primary cells in cell culture creates a bottleneck for the genetic modification of these cultures. In the current study, we show that the incorporation of the Rho-associated protein kinase (ROCK) inhibitor (Y-27632) during cell propagation extends the life span of primary human cells in vitro and thereby facilitates the incorporation of lentivirus-based expression systems. Using fluorescent reporters for fluorescence-activated cell sorting (FACS)-based sorting, we generated homogenously fluorescent hAEC cultures that differentiate normally after lentiviral transduction. As a proof-of-principle, we demonstrate that host gene expression can be modulated post-differentiation via inducible short hairpin (sh)RNA-mediated knockdown. Importantly, functional characterization of these transgenic hAEC cultures with exogenous poly (I:C), as a proxy for virus infection, demonstrates that such modifications do not influence the host innate immune response. Moreover, the propagation kinetics of both human coronavirus 229E (HCoV-229E) and human respiratory syncytial virus (hRSV) were not affected. Combined, these results validate our newly established protocol for the genetic modification of hAEC cultures, thereby unlocking a unique potential for detailed molecular characterization of virus–host interactions in human respiratory epithelium.

Amelogenic transcriptome profiling in ameloblast-like cells derived from adult gingival epithelial cells

Dental enamel is the highly mineralized tissue covering the tooth surface and is formed by ameloblasts. Ameloblasts have been known to be impossible to detect in adult tooth because they are shed by apoptosis during enamel maturation and tooth eruption. Owing to these, little was known about appropriate cell surface markers to isolate ameloblast-like cells in tissues. To overcome these problems, epithelial cells were selectively cultivated from the gingival tissues and used as a stem cell source for ameloblastic differentiation. When gingival epithelial cells were treated with a specified concentration of BMP2, BMP4, and TGFβ-1, the expression of ameloblast-specific markers was increased, and both the MAPK and Smad signaling pathways were activated. Gingival epithelial cells differentiated into ameloblast-like cells through epithelial-mesenchymal transition. By RNA-Seq analysis, we reported 20 ameloblast-specific genes associated with cell surface, cell adhesion, and extracellular matrix function. These cell surface markers might be useful for the detection and isolation of ameloblast-like cells from dental tissues.