Probes for INS

Patients with mutations in the ectodysplasin receptor signalling pathway genes - the X-linked ligand ectodysplasin-A (EDA), the receptorEDAR or the receptor adapter EDARADD - have hypohidrotic ectodermal dysplasia (HED). In addition to having impaired development of teeth, hair, eccrine sweat glands, and salivary and mammary glands, HED patients have ear, nose and throat disease. The mouse strains Tabby (EdaTa ) and downless (Edardl-J/dl-J ) have rhinitis and otitis media due to loss of submucosal glands in the upper airway. We report that prenatal correction of EDAR signalling in EdaTa mice with the agonist anti-EDAR antibody rescues the auditory-tube submucosal glands and prevents otitis media, rhinitis and nasopharyngitis. The sparse- and wavy-haired (swh) rat strain carries a mutation in the Edaradd gene and has similar cutaneous HED phenotypes to mouse models. We report that auditory-tube submucosal glands are smaller in the homozygous mutant Edaraddswh/swh than those in unaffected heterozygous Edaraddswh/+ rats, and that this predisposes them to otitis media. Furthermore, the pathogenesis of otitis media in the rat HED model differs from that in mice, as otitis media is the primary pathology, and rhinitis is a later-onset phenotype. These findings in rodent HED models imply that hypomorphic as well as null mutations in EDAR signalling pathway genes may predispose to otitis media in humans. In addition, this work suggests that the recent successful prenatal treatment of X-linked HED (XLHED) in humans may also prevent ear, nose and throat disease, and provides diagnostic criteria that distinguish HED-associated otitis media from chronic otitis media with effusion, which is common in children.

Fibroblast growth factor (FGF) signaling is essential for many developmental processes and plays a pivotal role in skeletal homeostasis, regeneration and wound healing. FGF signals through one of five tyrosine kinase receptors: Fgfr1a, -1b, -2, -3, -4. To characterize the expression of zebrafish fgfr3 from the larval stage to adulthood, we used RNAscope in situ hybridization on paraffin sections of the zebrafish head. Our study revealed spatial and temporal distribution of fgfr3 transcript in chondrocytes of the head cartilages, osteoblasts involved in bone formation, ventricular zone of the brain, undifferentiated mesenchymal cells of the skin, and lens epithelium of the eye. In general, the expression pattern of zebrafish fgfr3 is similar to the expression observed in higher vertebrates.

Although hundreds of cytosolic or transmembrane molecules form the primary cilium, few secreted molecules are known to contribute to ciliogenesis. Here, homologous secreted metalloproteases ADAMTS9 and ADAMTS20 are identified as ciliogenesis regulators that act intracellularly. Secreted and furin-processed ADAMTS9 bound heparan sulfate and was internalized by LRP1, LRP2 and clathrin-mediated endocytosis to be gathered in Rab11 vesicles with a unique periciliary localization defined by super-resolution microscopy. CRISPR-Cas9 inactivation of ADAMTS9 impaired ciliogenesis in RPE-1 cells, which was restored by catalytically active ADAMTS9 or ADAMTS20 acting in trans, but not by their proteolytically inactive mutants. Their mutagenesis in mice impaired neural and yolk sac ciliogenesis, leading to morphogenetic anomalies resulting from impaired hedgehog signaling, which is transduced by primary cilia. In addition to their cognate extracellular proteolytic activity, ADAMTS9 and ADAMTS20 thus have an additional proteolytic role intracellularly, revealing an unexpected regulatory dimension in ciliogenesis.