Biology subjects

Dupuy, F.

Publications and source records attributed to Dupuy, F..

4 recordsLinked to original sources

bioRxiv2026

Tuning T-cell immunological synapse by modular DNA-Nanobody engagers for precision immunotherapy

Bispecific T-cell engagers (TCEs) are a promising class of cancer immunotherapies, but their clinical use is limited by toxicity and insufficient specificity. Tuning the T cell- tumor interface through engager architecture may address these drawbacks. To this end, we engineered hybrid constructs composed of two nanobodies targeting CD3 and the model tumor antigen HER2, respectively, connected by rigid DNA linkers of variable length. Using cytotoxicity assays and hybrid biophysical platforms, we demonstrate a linker-length dependence of cell spreading on antigen, target killing and cytokine release, revealing a functional decoupling between killing and cytokine secretion, and implicating the glycocalyx as a key player. Through the addition of EGFR targeting, we also generate trispecific constructs implementing an "OR-gate" logic to address tumor heterogeneity and reduce resistance due to antigen loss. Overall, these versatile constructs show great therapeutic promise, and at the same time serve as platforms to test hypotheses on biophysical mechanisms.

synthetic biology↗

bioRxiv2024

Microvalve-based devices for flow-free gradient generators

Experiments with gradients of soluble bioactive species have significantly advanced with microfluidic developments that enable cell observation and stringent control of environmental conditions. While some methodologies rely on flow to establish gradients, other opt for flow-free conditions, which is particularly beneficial for studying non-adherent and/or shear-sensitive cells. In flow-free devices, bioactive species diffuse either through resistive microchannels in "microchannel-based" devices, a porous membrane in "membrane-based" devices, or a hydrogel in "gel-based" devices. However, despite significant advancements over traditional methods such as "Boyden chambers", these technologies have not widely disseminated in biological laboratories, arguably due to entrenched practices and the intricate skills required for conducting microfluidic assays. Here, we integrated Quake-type pneumatic microvalves in place of microgrooves, membranes, or gels, and developed devices with precise control over residual flow, establishment initial gradient, and long-term stability of gradients. The "Microvalve-based" approach enables the generation of the automatization of delicate microfluidic manipulations, which paves the way for routine applications of controlled and tunable flow-free gradients in academic laboratories and biomedical units.

biophysics↗

bioRxiv2021

Expression patterns of Plasmodium falciparum clonally variant genes at the onset of a blood infection in non-immune humans

Clonally variant genes (CVGs) play fundamental roles in the adaptation of Plasmodium falciparum parasites to the fluctuating conditions of the human host. However, their expression patterns under the natural conditions of the blood circulation have been characterized in detail only for a few specific gene families. Here we provide a detailed characterization of the complete P. falciparum transcriptome across the full intraerythrocytic development cycle (IDC) at the onset of a blood infection in non-immune human volunteers. We found that the vast majority of transcriptional differences between parasites obtained from the volunteers and the parental parasite line maintained in culture occur in CVGs. Specifically, we observed a major increase in the transcript levels of most members of the pfmc-2tm and gbp families and of specific genes of other families, in addition to previously reported changes in var and clag3 genes expression. Large transcriptional differences correlate with changes in the distribution of heterochromatin, confirming their epigenetic nature. The analysis of parasites collected at different time points along the infection indicates that when parasites pass through transmission stages, the epigenetic memory at CVG loci is lost, resulting in a reset of their expression state and reestablishment of new epigenetic patterns. ImportanceThe ability of malaria parasites to adapt to changes in the human blood environment, where they produce long term infection associated with clinical symptoms, is fundamental for their survival. Clonally variant genes, regulated at the epigenetic level, play a major role in this adaptive process, as changes in the expression of these genes result in antigenic and functional alterations that enable immune evasion and provide phenotypic plasticity. However, the way these genes are expressed under the natural conditions of the human circulation or how their expression is affected by passage through transmission stages is not well understood. Here we provide a comprehensive characterization of the expression patterns of these genes at the onset of human blood infections, which reveals major differences with in vitro cultured parasites and also distinctive alterations between different families of clonally variant genes. We also show that epigenetic patterns are erased and reestablished during transmission stages.

microbiology↗

bioRxiv2020

Plasmodium falciparum sexual parasites regulate infected erythrocyte permeability

To ensure the transport of nutrients necessary for their survival, Plasmodium falciparum parasites increase erythrocyte permeability to diverse solutes. These New Permeation Pathways (NPP) have been extensively characterized in the pathogenic asexual parasite stages, however the existence of NPP has never been investigated in gametocytes, the sexual stages responsible for transmission to mosquitoes. Here, we show that NPP are still active in erythrocytes infected with immature gametocytes and that this activity declines along gametocyte maturation. Our results indicate that NPP are regulated by cyclic AMP (cAMP) signaling cascade during sexual parasite stages, and that the decrease in cAMP levels in mature stages results in a slowdown of NPP activity. We also show that NPP facilitate the uptake of artemisinin derivatives and that phosphodiesterase (PDE) inhibitors can reactivate NPP and increase drug uptake in mature gametocyte-infected erythrocytes. These processes are predicted to play a key role in P. falciparum gametocyte biology and susceptibility to antimalarials.

microbiology↗