Dimerization of kringle 1 domain from hepatocyte growth factor/scatter factor provides a potent MET receptor agonist.

Hepatocyte growth factor/scatter factor (HGF/SF) and its cognate receptor MET play several essential roles in embryogenesis and regeneration in postnatal life of epithelial organs such as the liver, kidney, lung, and pancreas, prompting a strong interest in harnessing HGF/SF-MET signalling for regeneration of epithelial organs after acute or chronic damage. The limited stability and tissue diffusion of native HGF/SF, however, which reflect the tightly controlled, local mechanism of action of the morphogen, have led to a major search of HGF/SF mimics for therapy. In this work, we describe the rational design, production, and characterization of K1K1, a novel minimal MET agonist consisting of two copies of the kringle 1 domain of HGF/SF in tandem orientation.

High Throughput Blood-brain Barrier Organoid Generation and Assessment of Receptor-Mediated Antibody Transcytosis.

Targeting receptor-mediated transcytosis (RMT) is a successful strategy for drug delivery of biologic agents across the blood-brain barrier (BBB). The recent development of human BBB organoid models is a major advancement to help characterize the mechanisms of RMT and thus accelerate the design of brain delivery technologies. BBB organoids exhibit self-organization, which resembles the architecture of the neurovascular unit, and low paracellular permeability, due to the formation of tight junctions between endothelial cells.

Investigating receptor-mediated antibody transcytosis using blood-brain barrier organoid arrays.

Background: The pathways that control protein transport across the blood-brain barrier (BBB) remain poorly characterized. Despite great advances in recapitulating the human BBB in vitro, current models are not suitable for systematic analysis of the molecular mechanisms of antibody transport. The gaps in our mechanistic understanding of antibody transcytosis hinder new therapeutic delivery strategy development.

Validation of a Miniaturized Permeability Assay Compatible with CRISPR-Mediated Genome-Wide Screen.

The impermeability of the luminal endothelial cell monolayer is crucial for the normal performance of the vascular and lymphatic systems. A key to this function is the integrity of the monolayer's intercellular junctions. The known repertoire of junction-regulating genes is incomplete.

Murine -linked hydrocephalus is caused by hyperpermeability of the choroid plexus.

Though congenital hydrocephalus is heritable, it has been linked only to eight genes, one of which is Humans and mice that carry a truncated version of MPDZ incur severe hydrocephalus resulting in acute morbidity and lethality. We show by magnetic resonance imaging that contrast medium penetrates into the brain ventricles of mice carrying a loss-of-function mutation, whereas none is detected in the ventricles of normal mice, implying that the permeability of the choroid plexus epithelial cell monolayer is abnormally high. Comparative proteomic analysis of the cerebrospinal fluid of normal and hydrocephalic mice revealed up to a 53-fold increase in protein concentration, suggesting that transcytosis through the choroid plexus epithelial cells of KO mice is substantially higher than in normal mice.

Pannexin-1 in Human Lymphatic Endothelial Cells Regulates Lymphangiogenesis.

The molecular mechanisms governing the formation of lymphatic vasculature are not yet well understood. Pannexins are transmembrane proteins that form channels which allow for diffusion of ions and small molecules (<1 kDa) between the extracellular space and the cytosol. The expression and function of pannexins in blood vessels have been studied in the last few decades.

Semi-synthesis of a HGF/SF kringle one (K1) domain scaffold generates a potent MET receptor agonist.

The development of MET receptor agonists is an important goal in regenerative medicine, but is limited by the complexity and incomplete understanding of its interaction with HGF/SF (Hepatocyte Growth Factor/Scatter Factor). NK1 is a natural occurring agonist comprising the N-terminal (N) and the first kringle (K1) domains of HGF/SF. In the presence of heparin, NK1 can self-associate into a "head to tail" dimer which is considered as the minimal structural module able to trigger MET dimerization and activation whereas isolated K1 and N domains showed a weak or a complete lack of agonistic activity respectively.

The vitamin K-dependent anticoagulant factor, protein S, inhibits multiple VEGF-A-induced angiogenesis events in a Mer- and SHP2-dependent manner.

Protein S is a vitamin K-dependent glycoprotein, which, besides its anticoagulant function, acts as an agonist for the tyrosine kinase receptors Tyro3, Axl, and Mer. The endothelium expresses Tyro3, Axl, and Mer and produces protein S. The interaction of protein S with endothelial cells and particularly its effects on angiogenesis have not yet been analyzed.