Biology subjects

Bagley, D. C.

Publications and source records attributed to Bagley, D. C..

6 recordsLinked to original sources

bioRxiv2026

Starvation improves epithelial fitness by selectively extruding DNA damaged cells

During homeostasis, crowded cells with the lowest energy levels are eliminated by extrusion via Piezo1 signalling to maintain constant cell numbers. However, crowding-induced extrusion does not necessarily remove damaged or otherwise unfit cells. Here, we show that glucose or glutamine starvation triggers a rapid, regulated wave of extrusion, called starvation-induced cell extrusion (STICE), that selectively eliminates cells bearing DNA damage markers via a p53-dependent, Piezo1-independent pathway, improving monolayer fitness. Unlike non-extruding cells, which recycle contents through autophagy and lysosomal digestion, p53-activated cells instead use LC3 to drive lysosomal exocytosis, promoting extrusion signalling. By eliminating defective and transformed cells, STICE confers resistance to damage and apoptotic stimuli in the remaining monolayer. STICE thus acts as a tissue-level analogue of autophagy: rather than improving individual cells by digesting and recycling damaged components, it improves tissue fitness by eliminating substandard cells.

cell biology↗

bioRxiv2026

Piezo1 balances focal and reticular adhesions to enable EGFR clathrin-mediated endocytosis

Cells attach to the extracellular matrix through distinct integrin-mediated adhesive structures, including force-transmitting focal adhesions (FAs) and clathrin-enriched reticular adhesions (RAs). FAs enable mesenchymal cell migration and disassemble at mitotic entry, whereas RAs impede migration, persist during mitosis, and contribute to clathrin-mediated endocytosis (CME) as they disassemble. FAs grow with RhoA contractility, whereas RAs shrink, but the mechanisms coordinating these opposing responses remain unclear. Here, we identify the mechanically activated ion channel Piezo1 as a master regulator of FA/RA balance. Piezo1-dependent calcium influx activates the Src family kinase Fyn, which activates two actin polymerization pathways: FA and stress fiber growth via VAV2-RhoA and RA disassembly via N-WASP-Arp2/3. Inhibition or knockdown of Piezo1, Fyn, or VAV2 decreases FA size and increases RA coverage. Critically, cells lacking Piezo1 fail to internalize ligand-activated EGFR on stiff substrates despite normal CME on soft substrates, establishing an essential role for Piezo1 in EGFR CME mechanoadaption. Our findings reveal Piezo1 as the mechanosensor linking membrane tension to coordinated actin polymerization pathways that co-regulate cell-matrix adhesion and endocytosis. Given that CME contributes to viral entry into host cells and cancer resistance to anti-EGFR antibody therapy, targeting the Piezo1-RA-CME axis may offer novel therapeutic opportunities.

cell biology↗

bioRxiv2025

Human airway epithelia clear rhinovirus-infected cells using two waves of cell extrusion

Epithelial barriers represent the first line of defence against pathogens, yet their role in innate immunity is typ-ically relegated to pathogen detection and immune cell recruitment. This perspective ignores a fundamental evolutionary principle: epithelia defended against pathogens long before complex immune systems evolved. Here, we demonstrate that human bronchial epithelial monolayers retain this ancestral capacity, autono-mously clearing rhinovirus (RV) within 24 hours by selectively extruding infected cells--a process we term virus-induced cell extrusion (VICE). VICE occurs in two waves: a rapid response occurring independently of virus entry, followed by a replication-dependent wave. Barrier-defective epithelia that cannot extrude fail to clear RV. While extrusion maintains barrier integrity and eliminates local infection, it also expels virus-laden cells, promoting transmission. Thus, VICE enables leukocyte-independent epithelial defence while inadver-tently promoting viral transmission, reflecting an evolutionary strategy that prioritizes barrier integrity over containment. These findings redefine epithelia as central players in viral pathogenesis and host protection.

cell biology↗

bioRxiv2025

Inhibiting epithelial cell extrusion and inflammation synergistically reverses asthmatic airway remodelling

Airway smooth muscle (ASM) hyperresponsiveness is the defining feature of asthma, yet neither its origins nor the processes that establish and maintain it are understood. Here, using a mouse model, we show that hyperresponsiveness arises from ASM realignment into dense, parallel bundles reinforced by excess extracellular matrix, a fundamental remodelling rather than mere amplification of existing contractile ASM. This remodelling is initiated and sustained by a mechanical feedforward cycle. Allergen treatment initiates a contraction-relaxation cycle that realigns ASM into a bronchoconstrictive state. As bronchoconstriction triggers crowding and excess airway epithelial cell extrusion 1, the wounding then locks ASM into a hypercontractile architecture that drives further constriction. Gadolinium, a mechanosensitive channel blocker that inhibits extrusion, prevents this remodelling and hyperresponsiveness--unlike the corticosteroid budesonide. Critically, in mice with fully established disease, gadolinium reverses all asthmatic features and restores normal airway function, while budesonide alone cannot. Budesonide, however, synergises with gadolinium to normalise protein and gene expression. These findings reframe asthma pathogenesis as a mechanically driven, pharmacologically reversible process -- suggesting that asthma may be curable rather than merely treatable.

cell biology↗

bioRxiv2023

The mechanics of bronchoconstriction cause airway epithelial damage and inflammation by excess crowding-induced extrusion

Asthma is deemed an inflammatory disease, yet the defining diagnostic symptom is mechanical bronchoconstriction. We previously discovered a conserved process that drives homeostatic epithelial cell death in response to mechanical cell crowding called cell extrusion(1, 2). Here, we show that the pathological crowding of a bronchoconstrictive attack causes so much epithelial cell extrusion that it damages the airways, resulting in inflammation and mucus secretion. While relaxing airways with the rescue treatment albuterol did not impact these responses, inhibiting live cell extrusion signaling during bronchoconstriction prevented all these symptoms. Our findings propose a new etiology for asthma, dependent on the mechanical crowding of a bronchoconstrictive attack. Our studies suggest that blocking epithelial extrusion, instead of ensuing downstream inflammation, could prevent the feed-forward asthma inflammatory cycle.

cell biology↗

bioRxiv2023

Mon1a and FCHO2 are required for maintenance of Golgi architecture

Mon1a has been shown to function in the endolysosomal pathway functioning in the Mon1-Ccz1 complex and it also acts in the secretory pathway where it interacts with dynein and affects ER to Golgi traffic. Here we show that Mon1a is also required for maintenance of the Golgi apparatus. We identified the F-BAR protein FCHO2 as a Mon1a-interacting protein by both yeast two-hybrid analysis and co-immunoprecipitation. siRNA-dependent reductions in Mon1a or FCHO2 resulted in Golgi fragmentation. Membrane trafficking through the secretory apparatus in FCHO2-depleted cells was unaltered, however, reduction of FCHO2 affected the uniform distribution of Golgi enzymes necessary for carbohydrate modification. Fluorescence recovery after photobleaching analysis showed that the Golgi ministacks in Mon1a- or FCHO2-silenced cells did not exchange resident membrane proteins. The effect of FCHO2 silencing on Golgi structure was partially cell cycle-dependent and required mitosis-dependent Golgi fragmentation, whereas the effect of Mon1a-silencing on Golgi disruption was not cell cycle-dependent. mCherry-FCHO2 transiently colocalized on Golgi structures independent of Mon1a. These findings suggest that Mon1a has functions throughout the secretory pathway including interacting with dynein at the ER-Golgi interface in vesicle formation and then interacting with FCHO2 at the Golgi to generate lateral links between ministacks, thus creating Golgi ribbons.

cell biology↗