Therapeutic antibodies reveal Notch control of transdifferentiation in the adult lung

Abstract

Prevailing dogma holds that cell-cell communication through Notch ligands and receptors determines binary cell fate decisions during progenitor cell divisions, with differentiated lineages remaining fixed. Mucociliary clearance in mammalian respiratory airways depends on secretory cells (club and goblet) and ciliated cells to produce and transport mucus. During development or repair, the closely related Jagged ligands (JAG1 and JAG2) induce Notch signalling to determine the fate of these lineages as they descend from a common proliferating progenitor. In contrast to such situations in which cell fate decisions are made in rapidly dividing populations, cells of the homeostatic adult airway epithelium are long-lived, and little is known about the role of active Notch signalling under such conditions. To disrupt Jagged signalling acutely in adult mammals, here we generate antibody antagonists that selectively target each Jagged paralogue, and determine a crystal structure that explains selectivity. We show that acute Jagged blockade induces a rapid and near-complete loss of club cells, with a concomitant gain in ciliated cells, under homeostatic conditions without increased cell death or division. Fate analyses demonstrate a direct conversion of club cells to ciliated cells without proliferation, meeting a conservative definition of direct transdifferentiation. Jagged inhibition also reversed goblet cell metaplasia in a preclinical asthma model, providing a therapeutic foundation. Our discovery that Jagged antagonism relieves a blockade of cell-to-cell conversion unveils unexpected plasticity, and establishes a model for Notch regulation of transdifferentiation.

Multiciliated Cells in Animals

“…In addition, they are able to drive ectopic differentiation of MCCs in Xenopus skin/kidney and mouse airway epithelia (Stubbs et al 2012;Zhou et al 2015). GEMC1 and MCIDAS are therefore sufficient to trigger the full developmental program for secretoryto-ciliated cell conversion, which is consistent with the finding that this (trans-)differentiation process is Notch-dependent (Lafkas et al 2015;Pardo-Saganta et al 2015b). Hierarchically, MCIDAS lies downstream from GEMC1, although the molecular aspect of this control is unknown (Fig.…”

“…In the adult, ciliated cells can differentiate from both basal progenitors and secretory cells in mouse airways (Rawlins et al 2009;Lafkas et al 2015;Pardo-Saganta et al 2015b;Watson et al 2015). Electron microscopy (EM) suggests the same events of (trans-)differentiation from secretory-to-ciliated cells in human and quail oviducts under hormonal control Hagiwara 1995).…”

“…In addition, microRNAs, such as miR449, are specifically expressed in MCC progenitors in Xenopus skin and human airway developing epithelium, where they repress the Notch pathway by targeting Notch1 and its ligand DLL1 (Marcet et al 2011). Finally, in the adult mouse homeostatic airways, a recent study proposes that basal cells continuously supply their daughter secretory cells with a Notch ligand to avoid their terminal (trans-)differentiation into MCC (Lafkas et al 2015;Pardo-Saganta et al 2015b). …”

Constitutive NOTCH3 Signaling Promotes the Growth of Basal Breast Cancers

“…2A and B). However, potent antibody inhibitors of these JAG ligands (24) failed to block the constitutive NOTCH3 signal, in contrast to the inhibition from a GSI or anti-N3.A4 (Fig. 2B and C) and as observed in additional basal lines (data not shown).…”

Stars from the darkest night: unlocking the neurogenic potential of astrocytes in different brain regions

“…Once an identity switch has occurred, feed-forward and cross-repressive mechanisms should operate to make the new network stable, provided that the environment is permissive. This has been conceptually demonstrated in the lung, where transient Notch manipulation leads to permanent transdifferentiation of club cells to ciliated cells (Lafkas et al, 2015). A similar process is likely to occur when Notch signaling in astrocytes is reduced in response to stroke (Magnusson et al, 2014).…”