Biology subjects

Lafkas, D.

Publications and source records attributed to Lafkas, D..

4 recordsLinked to original sources

bioRxiv2024

Notch signaling stabilizes lengths of motile cilia in multiciliated cells in the lung

Airway multiciliated cells (MCs) maintain respiratory health by clearing mucus and trapped particles through the beating of motile cilia. While it is known that ciliary lengths decrease along the proximal-distal (P-D) axis of the tracheobronchial tree, how this is regulated is unclear. Here, we demonstrate that canonical Notch signaling in MCs plays a critical role in stabilizing ciliary length. Inhibition of Notch signaling in MCs results in ciliary shortening in the trachea, lengthening in the distal airway, and to region-specific alterations in gene expression. We probe how environmental challenges impact MC homeostasis using germ-free and Mycobacterium tuberculosis (M. tb) infection models. While germ-free conditions do not perturb ciliary lengths, M. tb infection leads to lengthening of distal airway cilia, correlating with a downregulation of Notch signaling. These findings reveal that ciliary length and the P-D gradient in the airways are actively regulated, with Notch signaling serving as a stabilizing mechanism.

cell biology↗

bioRxiv2024

The Jag2/Notch1 signaling axis promotes sebaceous gland differentiation and controls progenitor proliferation

The sebaceous gland (SG) is a vital appendage of the epidermis, and its normal homeostasis and function is crucial for effective maintenance of the skin barrier. Notch signaling is a well-known regulator of epidermal differentiation, and has also been shown to be involved in postnatal maintenance of SGs. However, the precise role of Notch signaling in regulating SG differentiation in the adult homeostatic skin remains unclear. While there is evidence to suggest that Notch1 is the primary Notch receptor involved in regulating the differentiation process, the ligand remains unknown. Using monoclonal therapeutic antibodies designed to specifically inhibit of each of the Notch ligands or receptors, we have identified the Jag2/Notch1 signaling axis as the primary regulator of sebocyte differentiation in homeostatic skin. Mature sebocytes are lost upon specific inhibition of the Jag2 ligand or Notch1 receptor, resulting in the accumulation of proliferative stem/progenitor cells in the SG. Strikingly, this phenotype is reversible, as these stem/progenitor cells re-enter differentiation when the inhibition of Notch activity is lifted. Thus, Notch activity promotes correct sebocyte differentiation, and is required to restrict progenitor proliferation.

developmental biology↗

bioRxiv2023

NEUROEPITHELIAL BODIES AND TERMINAL BRONCHIOLES ARE NICHES FOR DISTINCTIVE CLUB CELLS THAT CAN REPAIR AIRWAYS FOLLOWING ACUTE NOTCH INHIBITION

Airway club cells (CCs) have the dual role of a secretory cell and a progenitor cell. Using pharmacological, genetic, and cell-ablation approaches we probe the role of canonical Notch signalling in the regulation of the regenerative capacity of CCs. We report that in response to its perturbation, different subpopulations of CCs adopt distinct fates. Upon acute inhibition of Notch, the majority transdifferentiate into multiciliated cells. However, a "variant" subpopulation (v-CCs), juxtaposed with Neuroepithelial Bodies (5-10%) and neighbouring bronchioalveolar duct junctions (>80%), does not. Instead, v-CCs transition into partially differentiated/lineage ambiguous states but can revert to a CC fate upon restoration of Notch signalling and repopulate the airways with CCs and multiciliated cells. Analysis of a v-CC lineage marker (Uroplakin3a), coupled with sequential Notch inhibition, reveals that differential responses of v-CCs to Notch inhibition are regulated by their cellular microenvironment. We propose that perturbations to Notch signalling may be a common consequence of airway injury and that microenvironmental signals diversify CCs to create a robust pool that can repair airways upon acute Notch inhibition.

cell biology↗

bioRxiv2020

Single cell reconstruction of human basal cell diversity in normal and IPF lung.

RationaleDeclining lung function in patients with interstitial lung disease is accompanied by epithelial remodeling and progressive scarring of the gas-exchange region. There is a need to better understand the contribution of basal cell hyperplasia and associated mucosecretory dysfunction to the development of idiopathic pulmonary fibrosis (IPF). ObjectivesWe sought to decipher the transcriptome of freshly isolated epithelial cells from normal and IPF lung to discern disease-dependent changes within basal stem cells. MethodsSingle cell RNA sequencing was used to map epithelial cell types of the normal and IPF human airway. Organoid and ALI cultures were used to investigate functional properties of basal cell subtypes. Measurements and Main ResultsWe found that basal cells included multipotent and secretory primed subsets in control adult lung tissue. Secretory primed basal cells include an overlapping molecular signature with basal cells obtained from distal lung tissue of IPF lungs. We confirmed that NOTCH2 maintains undifferentiated basal cells and restrict basal-to-ciliated differentiation, and present evidence that NOTCH3 functions to restrain secretory differentiation. ConclusionsBasal cells are dynamically regulated in disease and are specifically biased towards expansion of the secretory primed basal cell subset in idiopathic pulmonary fibrosis. Modulation of basal cell plasticity may represent a relevant target for therapeutic intervention in IPF.

cell biology↗