Biology subjects

Anastasio, A.

Publications and source records attributed to Anastasio, A..

4 recordsLinked to original sources

bioRxiv2025

Life-history trade-offs explain local adaptation in Arabidopsis thaliana

Local adaptation has been demonstrated in many organisms, but the traits involved, and the temporal and spatial scales at which selection acts are generally unknown. We carried out a multi-year study of 200 accessions (natural inbred lines) of Swedish Arabidopsis thaliana using local field sites and a combination of common-garden experiments that measured adult survival and fecundity, and selection experiments that measured fitness over the full life cycle. We found evidence of strong and variable selection, with particular genotypes favored more than five-fold in certain years and locations. Fecundity showed evidence of classical local adaptation, with accessions generally performing better closer to their home. However, relative to other accessions, southern ones usually had the highest fecundity---but were far more sensitive to harsh winters and slug herbivory, which strongly decreased both survival and fecundity. Furthermore, accessions originally sampled on beaches had low fecundity in all common-garden experiments, but massively outperformed all other accessions in the selection experiments, presumably due to an advantage during seedling establishment associated with their very large seeds. We conclude that local adaptation in A. thaliana reflects strong temporally and spatially varying selection on multiple traits, generally involving trade-offs and different life-history strategies, making fitness difficult to predict and measure.

genetics↗

bioRxiv2023

Targeting BTN2A1 enhances Vγ9Vδ2 T cell effector functions and triggers tumor cells pyroptosis

V{gamma}9V{delta}2 T cells are potent but elusive cytotoxic effectors. Means to stimulate their function could lead to powerful new cancer immunotherapies. BTN2A1, a surface protein has recently been shown to bind the V{gamma}9 chain of the {gamma}{delta} TCR but its precise role in modulating V{gamma}9V{delta}2 T cells functions remains unknown. Here we show that 107G3B5, a monoclonal anti-BTN2A1 agonist antibody, significantly enhances V{gamma}9V{delta}2 T cell functions against hematological or solid cell lines and against primary cells from adult acute lymphoblastic leukemia patients. New computer vision strategies applied to holotomographic microscopy videos show that 107G3B5 enhances the interaction between V{gamma}9V{delta}2 T cells and target cells in a quantitative and qualitative manner. In addition, we provide evidence that V{gamma}9V{delta}2 T cells activated by 107G3B5 induce caspase 3/7 activation in tumor cells, thereby triggering their death by pyroptosis. We thus demonstrate that targeting BTN2A1 with 107G3B5 enhances the V{gamma}9V{delta}2 T cell antitumor response by triggering the pyroptosis-induced immunogenic cell death.

cancer biology↗

bioRxiv2022

Light-inducible T cell engagers trigger, tune and shape the activation of primary T cells

To mount appropriate responses, T cells integrate complex sequences of receptor stimuli perceived during transient interactions with antigen presenting cells. Although it has been hypothesized that the dynamics of these interactions influence the outcome of T cell activation, methodological limitations have hindered its formal demonstration. Here, we have engineered the Light-inducible T cell engager (LiTe) system, a recombinant optogenetics-based molecular tool targeting the T Cell Receptor (TCR). The LiTe system constitutes a reversible molecular switch displaying exquisite reactivity. As proof of concept, we dissect how specific temporal patterns of TCR stimulation shape T cell activation patterns. We established that CD4+ T cells respond to intermittent TCR stimulation more efficiently than their CD8+ T cells counterparts and provide evidence that distinct sequences of TCR stimulation encode different cytokine programs. Finally, we show that the LiTe system could be exploited to create light-activated bispecific T cell engagers and manipulate tumor cell killing. Overall, the LiTe system provides new opportunities to understand how T cells integrate TCR stimulations and to trigger T cell cytotoxicity with a high spatiotemporal control.

immunology↗

bioRxiv2017

Plant genes influence microbial hubs that shape beneficial leaf communities

Although complex interactions between hosts and microbial associates are increasingly well documented, we still know little about how and why hosts shape microbial communities in nature. In addition, host genetic effects on microbial communities vary widely depending on the environment, obscuring conclusions about which microbes are impacted and which plant functions are important. We characterized the leaf microbiota of 200 A. thaliana genotypes in eight field experiments and detected consistent host effects on specific, broadly distributed microbial OTUs. Host genetics disproportionately influenced hubs within the microbial communities, with their impact then percolating through the community, as evidenced by a decline in the heritability of particular OTUs with their distance to the nearest hub. By simultaneously measuring host performance, we found that host genetics associated with microbial hubs explained over 10% of the variation in lifetime seed production among host genotypes across sites and years. We successfully cultured one of these microbial hubs and demonstrated its growth-promoting effects on plants grown in sterile conditions. Finally, genome-wide association mapping identified many putatively causal genes with small effects on the relative abundance of microbial hubs across sites and years, and these genes were enriched for those involved in the synthesis of specialized metabolites, auxins and the immune system. Using untargeted metabolomics, we corroborate the consistent association of variation in specialized metabolites and microbial hubs across field sites. Together, our results reveal that host natural variation impacts the microbial communities in consistent ways across environments and that these effects contribute to fitness variation among host genotypes.

microbiology↗