Biology subjects

Dehio, P.

Publications and source records attributed to Dehio, P..

3 recordsLinked to original sources

bioRxiv2024

Antibiotic lethality dictates mycobacterial infection outcomes

Antibiotic development and treatment focus on bacterial growth inhibition, often with limited success. Here, we introduce Antimicrobial Single-Cell Testing (ASCT), an advanced imaging strategy to assess bacterial killing in real-time. By tracking 140 million bacteria and generating over 20,000 in vitro time-kill curves, we can predict Mycobacterium tuberculosis treatment outcomes in mice and humans and link strain-specific survival (drug tolerance) in Mycobacterium abscessus to clinical responses. Using ASCT, we reveal drug tolerance as a distinct genetically encoded bacterial trait conserved across drugs with similar targets and, via genome-wide associations, uncover molecular mechanisms that govern bacterial killing. This study establishes the technical framework and in vivo validation for large-scale bacterial killing assessments to advance our understanding of bacterial survival, antibiotic development and clinical decision-making.

microbiology↗

bioRxiv2024

A lymphoid tissue chemokine checkpoint prevents loss of CD8+ T cell functionality

The generation of effector CD8+ T cells (TEFF) requires activation of naive CD8+ T cells (TN) by dendritic cells (DCs) within lymphoid tissue. To date, it remains elusive how the duration of TN-DC interactions and integration of activation signals are controlled in vivo. Here, we report that lymphoid stroma-secreted ligands for CCR7 constrained interaction duration by gradually inducing CD8+ T cell release from DCs. At late time points of interactions, CCR7 ligands repositioned the F-actin-promoting factor DOCK2 away from the DC interface to enable CD8+ T cell detachment, proliferation onset and acquisition of cytotoxicity. Lack of CCR7 signaling, as during ex vivo activation or in chronically inflamed lymphoid tissue, caused sustained T cell-DC interactions, and generated dysfunctional TEFF with high expression of inhibitory receptors, impaired antimicrobial activity, and poor recall responses. In sum, our findings uncover that lymphoid stromal chemokines act as built-in "disruptors" of T cell-DC interactions for long-term preservation of TEFF functionality.

immunology↗

bioRxiv2024

An evolutionary-conserved VPS34-PIKfyve-TRPML1-Myosin II axis regulates the speed of amoeboid cell migration

Amoeboid cell migration is key to efficient T cell immunity. Spatial polarization of organelles within cells, including endo-lysosomes, is a prerequisite of migration. However, how ultrastructural polarization is linked to the signaling requirements governing T cell migration, remains unknown. Here we show that signaling molecules generated by endo-lysosome-localized kinases regulate velocity of amoeboid migration. Specifically, imaging of T cells identified accumulation of endo-lysosomes decorated with the lipid kinases VPS34-PIKfyve at the uropod of polarized cells. Activity of VPS34 and PIKfyve regulated speed, but not directedness, of migrating T cells. Mechanistically, PI(3,5)P2 generated by the sequential action of VPS34 and PIKfyve mediated Ca2+ efflux from lysosomes via the mucolipin TRP cation channel 1 (TRPML1), thus controlling activity of myosin IIA and hence the generation of propulsive force through retrograde actin flow. The VPS34-PIKfyve kinases also regulated velocity of myeloid cells, as well as of the amoeba Dictyostelium discoideum - establishing the axis as an evolutionary conserved speed control system of amoeboid cell migration. Graphical AbstractO_LIThe VPS34-PIKfyve axis is active on endo-lysosomes at the uropod of migrating T cells. C_LIO_LIVPS34 and PIKfyve promote myosin IIA activation and retrograde action flow. C_LIO_LIAmoeboid cell migration speed is controlled by VPS34 and PIKfyve via TRPML1. C_LIO_LIRegulation of amoeboid migration speed is a conserved function of the VPS34-PIKfyve axis. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=83 SRC="FIGDIR/small/575998v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1b70e64org.highwire.dtl.DTLVardef@111d052org.highwire.dtl.DTLVardef@83bc24org.highwire.dtl.DTLVardef@b51931_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗