Molecular basis of egg coat cross-linking sheds light on ZP1-associated female infertility.

Mammalian fertilisation begins when sperm interacts with the egg zona pellucida (ZP), whose ZP1 subunit is important for fertility by covalently cross-linking ZP filaments into a three-dimensional matrix. Like ZP4, a structurally-related component absent in the mouse, ZP1 is predicted to contain an N-terminal ZP-N domain of unknown function. Here we report a characterisation of ZP1 proteins carrying mutations from infertile patients, which suggests that, in human, filament cross-linking by ZP1 is crucial to form a stable ZP.

Structure of mammalian plasma fetuin-B and its mechanism of selective metallopeptidase inhibition.

Mammalian fetuin-A and fetuin-B are abundant serum proteins with pleiotropic functions. Fetuin-B is a highly selective and potent inhibitor of metallo-peptidases (MPs) of the astacin family, which includes ovastacin in mammals. By inhibiting ovastacin, fetuin-B is essential for female fertility.

A radical switch in clonality reveals a stem cell niche in the epiphyseal growth plate.

Longitudinal bone growth in children is sustained by growth plates, narrow discs of cartilage that provide a continuous supply of chondrocytes for endochondral ossification. However, it remains unknown how this supply is maintained throughout childhood growth. Chondroprogenitors in the resting zone are thought to be gradually consumed as they supply cells for longitudinal growth, but this model has never been proved.

Characterization of a mutation in the zona pellucida module of Endoglin that causes Hereditary Hemorrhagic Telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is a vascular rare disease characterized by nose and gastrointestinal bleeding, skin and mucosa telangiectasias, and arteriovenous malformations in internal organs. HHT shows an autosomal dominant inheritance and a worldwide prevalence of approximately 1:5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG (HHT1) or ACVRL1 (HHT2) genes, which code for the membrane proteins Endoglin and Activin A Receptor Type II-Like Kinase 1 (ALK1), respectively, both belonging to the TGF-β/BMP signaling pathway.

Dermal Condensate Niche Fate Specification Occurs Prior to Formation and Is Placode Progenitor Dependent.

Cell fate transitions are essential for specification of stem cells and their niches, but the precise timing and sequence of molecular events during embryonic development are largely unknown. Here, we identify, with 3D and 4D microscopy, unclustered precursors of dermal condensates (DC), signaling niches for epithelial progenitors in hair placodes. With population-based and single-cell transcriptomics, we define a molecular time-lapse from pre-DC fate specification through DC niche formation and establish the developmental trajectory as the DC lineage emerges from fibroblasts.

Single-Cell Transcriptomics of Traced Epidermal and Hair Follicle Stem Cells Reveals Rapid Adaptations during Wound Healing.

Epithelial tissues, such as the skin, rely on cellular plasticity of stem cells (SCs) from different niches to restore tissue function after injury. How these molecularly and functionally diverse SC populations respond to injury remains elusive. Here, we genetically labeled Lgr5- or Lgr6-expressing cells from the hair follicle bulge and interfollicular epidermis (IFE), respectively, and monitored their individual transcriptional adaptations during wound healing using single-cell transcriptomics.

Synergistic cross-talk of hedgehog and interleukin-6 signaling drives growth of basal cell carcinoma.

Persistent activation of hedgehog (HH)/GLI signaling accounts for the development of basal cell carcinoma (BCC), a very frequent nonmelanoma skin cancer with rising incidence. Targeting HH/GLI signaling by approved pathway inhibitors can provide significant therapeutic benefit to BCC patients. However, limited response rates, development of drug resistance, and severe side effects of HH pathway inhibitors call for improved treatment strategies such as rational combination therapies simultaneously inhibiting HH/GLI and cooperative signals promoting the oncogenic activity of HH/GLI.

MicroRNA-132 with Therapeutic Potential in Chronic Wounds.

Chronic wounds represent a major and rising health and economic burden worldwide. There is a continued search toward more effective wound therapy. We found significantly reduced microRNA-132 (miR-132) expression in human diabetic ulcers compared with normal skin wounds and also in skin wounds of leptin receptor-deficient (db/db) diabetic mice compared with wild-type mice.

Structural Basis of the Human Endoglin-BMP9 Interaction: Insights into BMP Signaling and HHT1.

Endoglin (ENG)/CD105 is an essential endothelial cell co-receptor of the transforming growth factor β (TGF-β) superfamily, mutated in hereditary hemorrhagic telangiectasia type 1 (HHT1) and involved in tumor angiogenesis and preeclampsia. Here, we present crystal structures of the ectodomain of human ENG and its complex with the ligand bone morphogenetic protein 9 (BMP9). BMP9 interacts with a hydrophobic surface of the N-terminal orphan domain of ENG, which adopts a new duplicated fold generated by circular permutation.

Single-Cell Transcriptome Profiling of Human Pancreatic Islets in Health and Type 2 Diabetes.

Hormone-secreting cells within pancreatic islets of Langerhans play important roles in metabolic homeostasis and disease. However, their transcriptional characterization is still incomplete. Here, we sequenced the transcriptomes of thousands of human islet cells from healthy and type 2 diabetic donors.

Single-Cell Transcriptomics Reveals that Differentiation and Spatial Signatures Shape Epidermal and Hair Follicle Heterogeneity.

The murine epidermis with its hair follicles represents an invaluable model system for tissue regeneration and stem cell research. Here we used single-cell RNA-sequencing to reveal how cellular heterogeneity of murine telogen epidermis is tuned at the transcriptional level. Unbiased clustering of 1,422 single-cell transcriptomes revealed 25 distinct populations of interfollicular and follicular epidermal cells.

Isolation and Fluorescence-Activated Cell Sorting of Mouse Keratinocytes Expressing β-Galactosidase.

During the past decade, the rapid development of new transgenic and knock-in mouse models has propelled epidermal stem-cell research into "fast-forward mode". It has become possible to identify and visualize defined cell populations during normal tissue maintenance, and to follow their progeny during the processes of homeostasis, wound repair, and tumorigenesis. Moreover, these cells can be isolated using specific labels, and characterized in detail using an array of molecular and cell biology approaches.

Dynamics of Lgr6⁺ Progenitor Cells in the Hair Follicle, Sebaceous Gland, and Interfollicular Epidermis.

The dynamics and interactions between stem cell pools in the hair follicle (HF), sebaceous gland (SG), and interfollicular epidermis (IFE) of murine skin are still poorly understood. In this study, we used multicolor lineage tracing to mark Lgr6⁺ -expressing basal cells in the HF isthmus, SG, and IFE.We show that these Lgr6⁺ cells constitute long-term self-renewing populations within each compartment in adult skin.

Variant Profiling of Candidate Genes in Pancreatic Ductal Adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis. Variant profiling is crucial for developing personalized treatment and elucidating the etiology of this disease.

Methods: Patients with PDAC undergoing surgery from 2007 to 2012 (n = 73) were followed from diagnosis until death or the end of the study.

Aberrant splicing of genes involved in haemoglobin synthesis and impaired terminal erythroid maturation in SF3B1 mutated refractory anaemia with ring sideroblasts.

Refractory anaemia with ring sideroblasts (RARS) is distinguished by hyperplastic inefficient erythropoiesis, aberrant mitochondrial ferritin accumulation and anaemia. Heterozygous mutations in the spliceosome gene SF3B1 are found in a majority of RARS cases. To explore the link between SF3B1 mutations and anaemia, we studied mutated RARS CD34(+) marrow cells with regard to transcriptome sequencing, splice patterns and mutational allele burden during erythroid differentiation.

Transcriptome analysis of controlled and therapy-resistant childhood asthma reveals distinct gene expression profiles.

Background: Children with problematic severe asthma have poor disease control despite high doses of inhaled corticosteroids and additional therapy, leading to personal suffering, early deterioration of lung function, and significant consumption of health care resources. If no exacerbating factors, such as smoking or allergies, are found after extensive investigation, these children are given a diagnosis of therapy-resistant (or therapy-refractory) asthma (SA).

Objective: We sought to deepen our understanding of childhood SA by analyzing gene expression and modeling the underlying regulatory transcription factor networks in peripheral blood leukocytes.