Lin, y. | Search bioRxiv

bioRxiv2024

Env from EIAV vaccine delicately regulates NLRP3 activation via attenuating NLRP3-NEK7 interaction

The current equine infectious anemia virus (EIAV) vaccine causes attenuation of the inflammatory response to an appropriate level, compared to that produced by virulent EIAV. However, how the EIAV vaccine finely regulates the inflammatory response remains unclear. Using a constructed NLRP3-IL-1{beta} screening system, viral proteins from two EIAV strains (the attenuated vaccine and its virulent mother strain) were examined separately. Firstly, EIAV-Env was screened to direct binding P2X7(R) with notable K+ efflux trans-cellularly. Secondly, EIAV-Env was found to bind NLRP3 and/or NEK7 to trigger aggregation of NLRP3-NEK7 to form NLRP3-NEK7 complex in cells. Comparison of the two strains, we observed a significant reduction on vaccine-Env-initiated NLRP3-NEK7 complex formation, with no difference in Env triggering P2X7(R)-mediated ion fluxes. Thirdly, reciprocally mutation on four stable varied amino acids between two strains produced an anticipated outcome on NLRP3-IL-1{beta}-axis activation. As the attenuated vaccine was shown evolved as a natural quasispecies of the virulent EIAV, its precise and adaptable regulation via spatial proximity-dependent intracellular activation might present a "win-win" virus-host adaption, offering an alternative strategy on HIV vaccine development. Author SummaryHere, we report that EIAV-Env mediates NLRP3 inflammasome activation through two distinct pathways. The first pathway involves a transcellular mechanism driven by K+ flux, which couples Env-P2X7 interaction. The second pathway entails direct intracellular binding between Env and NLRP3, promoting the assembly of NLRP3-NEK7 and subsequent inflammasome formation. Notably, we observed a marked difference in NLRP3 inflammasome activation between the vaccine and virulent strains, which was reflected in the extent of Env-mediated NLRP3-NEK7 aggregation. This study not only enhances our understanding of lentivirus-host immune interactions but also contributes to the broader discourse on virus evolution and host-induced inflammation.

immunology↗

bioRxiv2021

Visceral organ morphogenesis via calcium-patterned muscle contractions

How organs achieve their final shape is a problem at the interface between physics and developmental biology. Organs often involve multiple interacting tissue layers that must be coordinated to orchestrate the complex shape changes of development. Intense study uncovered genetic, and physical ingredients driving the form of mono layer tissue. Yet, tracing dynamics across tissue layers, and scales - from cell to tissue, to entire organs - remains an outstanding challenge. Here, we study the midgut of Drosophila embryos as a model visceral organ, to reconstruct in toto the dynamics of multi-layer organ formation in vivo. Using light-sheet microscopy, genetics, computer vision, and tissue cartography, we extract individual tissue layers to map the time course of shape across scales from cells to organ. We identify the kinematic mechanism driving the shape change due to tissue layer interactions by linking out-of-plane motion to active contraction patterns, revealing a convergent extension process in which cells deform as they flow into deepening folds. Acute perturbations of contractility in the muscle layer using non-neuronal optogenetics reveals that these contraction patterns are due to muscle activity, which induces cell shape changes in the adjacent endoderm layer. This induction cascade relies on high frequency calcium pulses in the muscle layer, under the control of hox genes. Inhibition of targets of calcium involved in myosin phosphorylation abolishes constrictions. Our study of multi-layer organogenesis reveals how genetic patterning in one layer triggers a dynamic molecular mechanism to control a physical process in the adjacent layer, to orchestrate whole-organ shape change.

developmental biology↗