Assemblies of JAG1 and JAG2 determine tracheobronchial cell fate in mucosecretory lung disease

Abstract

Mucosecretory lung disease compromises airway epithelial function and is characterized by goblet cell hyperplasia and ciliated cell hypoplasia. These cell types are derived from tracheobronchial stem/progenitor cells via a Notch dependent mechanism. Although specific arrays of Notch receptors regulate cell fate determination, the function of the ligands Jagged1 (JAG1) and Jagged2 (JAG2) is unclear. This study examined JAG1 and JAG2 function using human air-liquid-interface cultures that were treated with γ-secretase complex inhibitors (GSC), neutralizing peptides/antibodies, or WNT/β-catenin pathway antagonists/agonists. These experiments revealed that JAG1 and JAG2 regulated cell fate determination in the tracheobronchial epithelium; however, their roles did not adhere to simple necessity and sufficiency rules. Biochemical studies indicated that JAG1 and JAG2 underwent posttranslational modifications that resulted in generation of a JAG1 C-terminal peptide and regulated the abundance of full-length JAG2 on the cell surface. The GSC and glycogen synthase kinase 3 were implicated in these post-translational events but WNT agonist/antagonist studies and RNA sequencing indicated a WNT-independent mechanism.Collectively, these data suggest that post-translational modifications create distinct assemblies of JAG1 and JAG2 which regulate Notch signal strength and determine the fate of tracheobronchial stem/progenitor cells. the trachea and bronchi of the mouse and upper respiratory tract of humans. Lineage-tracing in mice (1-4) and clonal analysis in human (5) indicated that the TSC was a basal cell subtype.Previous studies reported that tracheobronchial ciliated and secretory cells were present in approximately equal numbers and that their frequency was regulated by Notch signaling (reviewed in (6, 7)). According to this model, signaling occurred between adjacent cells which expressed Notch ligands (jagged (JAG) 1 or 2 or delta-like (DLL) 1, 3, or 4) or notch receptors (NOTCH1, 2, 3, or 4) (6, 8). Following receptor ligation, ADAM10 or ADAM17 cleaved NOTCH at an extracellular site and the γ-secretase complex (GSC) cleaved NOTCH at an intracellular site. This process released the NOTCH intracellular domain which formed a transcriptional complex with several proteins including RBPJ and activated expression of the HES and HEY family of transcriptional repressors (9-11).Chronic lung disease is frequently associated a disruption of mucociliary clearance. In asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis (CB), and idiopathic pulmonary fibrosis (IPF) goblet cell hyperplasia and excess mucus secretion drive the mucosecretory phenotype. Single cell RNAseq (scRNAseq) analysis of asthma, IPF, and COPD indicated that Notch signaling was aberrant (12-14) and functional studies indicated that cigarette smoke, an agent which increases risk of developing COPD, CB, or IPF, activated Notch signaling (15). Mucociliary clearance can also be disrupted by ozone and cigarette smoke exposure or infection with SARS-Co...

Loss of an extensive ciliary connectome induces proteostasis and cell fate switching in a severe motile ciliopathy

“…Enrichment analysis of differential gene expression in multiciliated cells (Cil3), identified cilia structure and function, proteostasis, cell stress, oxidative phosphorylation, and Notch signaling pathways (Figure 6B, Figure S3B-S3F). Genes upregulated have roles in: (1) proteostasis, including components of the E3 ubiquitin ligase complex 62 , multiple proteasome subunits, heat shock chaperone proteins that handle unfolded proteins and aggregates 63 (Figure S3B, S3E); (2) cell stress response genes that include SAA1, SAA2, and SAA4, which are secreted acute phase reactants in sterile inflammation 64,65 (Figure 6B), (3) mitochondrial complex I subunits of NADH ubiquinone oxidoreductase and complex V subunits of ATP synthase indicating upregulation of ATP production (Figure S3C); and (4) HES1, a target of Notch signaling that increases secretory cell differentiation and airway secretory cell proteins [66][67][68] (Figure 6B). Together, these data indicate the presence of cellular stress in the variant cells, possibly due to the need to degrade the large burden of undocked connectome proteins.…”

Alveolar Organoids in Lung Disease Modeling

“…Multiciliated and secretory (including goblet and club) cell types originate from the tracheobronchial epithelial tissuespecific cells. They regenerate the pseudostratified airway epithelium and are located in the trachea and bronchi of the mouse and the upper respiratory tract of humans [37]. Neuroendocrine cells can be found as solitary cells [38].…”