Frattolin, J. | Search bioRxiv

bioRxiv2026

Fluid shear magnitude, mechanical history and actin-sensitive coupling shape Piezo1 signalling

Mechanical forces shape cell behaviour, yet how Piezo1-associated responses encode force magnitude, recent mechanical history and cytoskeletal context under repeated fluid shear remains unclear. We combined defined fluid shear stress (FSS) with GenEPi, a genetically encoded reporter of Piezo1-proximal Ca2+ entry, in engineered XLGenEPi-HEK293T monolayers to resolve mechanically evoked responses at single-cell and population scales. GenEPi responses increased with FSS magnitude but showed diminishing response gain at higher shear. Repeated submaximal FSS produced history-dependent attenuation and reduced temporal coordination, with higher FSS accelerating the early phase of attenuation. Low-dose Latrunculin A, without significantly reducing bulk F-actin abundance, converted sustained FSS-evoked signalling into a brief, decay-dominated response while largely preserving peak responses to Yoda1. These findings show that Piezo1-associated signalling is shaped over minutes by force magnitude, recent mechanical history and actin-sensitive mechanical coupling, providing a quantitative framework for understanding mechanotransduction under sustained and repeated mechanical stimulation.

biophysics↗

bioRxiv2020

Modelling the effects of lymph node swelling on T-cell response

Swelling of lymph nodes is commonly observed during the adaptive immune response, yet the impact on T cell trafficking and subsequent immune response is not well known. To better understand the effect of macro-scale alterations, we developed an agent-based model of the lymph node para-cortex, describing T cell trafficking and response to antigen-presenting dendritic cells alongside swelling-induced changes in T cell recruitment and egress, and regulation of expression of egress-modulating T cell receptor Sphingosine-1-phosphate receptor-1. Analysis of effector T cell response under varying swelling conditions showed that swelling consistently aided T cell activation. However, subsequent effector CD8+ T cell production could be reduced if swelling occurred too early in the T cell proliferative phase or if T cell cognate frequency was low due to increased opportunity for T cell exit. Temporarily extending retention of newly differentiated effector T cells, mediated by Sphingosine-1-phosphate receptor-1 expression, mitigated any negative effects of swelling by allowing facilitation of activation to outweigh increased access to exit areas. These results suggest targeting temporary effector T cell retention and egress associated with swelling may offer new ways to modulate effector TC responses in, for example, immuno-suppressed patients and optimisation of vaccine design.

immunology↗