Biology subjects

Laganiere, J.

Publications and source records attributed to Laganiere, J..

4 recordsLinked to original sources

bioRxiv2025

Soil microbiomes reveal different strategies for nitrogen acquisition in aspen-dominated stands from Mexico and Canada

Plant species shape soil microbiome composition through species-specific interactions. However, it is less clear how these interactions vary across populations that diverged a long time ago. In this study, we explore the influence of host genetic composition and edaphic factors on the soil microbiome of Populus tremuloides, one of North Americas most widespread tree species. Using 16S, 18S rRNA gene, and ITS2 region metabarcoding on soils from natural stands and potting mix, rhizosphere, and root samples from a greenhouse common garden, we examined prokaryotic and fungal communities in two aspen genetic groups. The Eastern Canada group represents boreal and cold temperate ecoregions, and the one from Northwestern Mexico represents warm temperate ecoregion. Variation in microbial community structure correlated with soil properties but results from common gardens indicated that the host genetic makeup may also play a role. The three ecoregions showed functional divergence: warm temperate sites hosted a higher abundance and diversity of nitrogen-fixing bacteria, while boreal stands exhibited stronger associations with ectomycorrhizal fungi. Our findings highlight how local adaptations to climate and soil conditions in aspen extend to their microbial partners, emphasizing the potential role of host-microbe interactions in shaping tree resilience and susceptibility to future climate changes.

evolutionary biology↗

bioRxiv2023

MTOR as a selectable genomic harbor for CRISPR-engineered CAR-T cell therapy

Chimeric antigen receptors (CARs) reprogram T cells to recognize and target cancer cells. Despite remarkable responses observed with CAR-T cell therapy in patients with hematological malignancies, CAR-T cell engineering still relies mostly on randomly integrating vectors, limiting the possibilities of fine-tuning T cell function. Here, we designed a CRISPR-based marker-free selection strategy to simultaneously target a therapeutic transgene and a gain-of-function mutation to the MTOR locus to enrich cells resistant to rapamycin, a clinically used immunosuppressant. We readily engineered rapamycin-resistant (RapaR) CAR-T cells by targeting CAR expression cassettes to the MTOR locus. Using in vitro cytotoxicity assays, and a humanized mouse model of acute lymphoblastic leukemia, we show that RapaR-CAR-T cells can efficiently target CD19+ leukemia cells in presence of immunosuppressing doses of rapamycin. Furthermore, our strategy allows multiplexed targeting of rapamycin-regulated immunoreceptors complexes (DARICs) to the MTOR and TRAC loci to pharmacologically control CAR-T cells activity. We foresee that our approach could both facilitate the enrichment of CRISPR-engineered CAR-T cells ex vivo and in vivo while improving tumor eradication.

cancer biology↗

bioRxiv2022

Accessory-cell-free differentiation of hematopoietic stem and progenitor cells into mature red blood cells

The culture and ex vivo engineering of red blood cells (RBCs) can help characterize genetic variants, model diseases, and may eventually spur the development of applications in transfusion medicine. In the last decade, improvements to the in vitro production of RBCs have enabled efficient erythroid progenitor proliferation and high enucleation levels from several sources of hematopoietic stem and progenitor cells (HSPCs). Despite these advances, there remains a need for refining the terminal step of in vitro human erythropoiesis -- i.e., the terminal maturation of reticulocytes into erythrocytes -- so that it can occur without feeder or accessory cells and animal components. Here, we describe the near-complete erythroid differentiation of cultured RBCs (cRBCs) from adult HSPCs in accessory-cell-free and animal-component-free conditions. The approach improves post-enucleation cell integrity and cell survival, and enables subsequent storage of cRBCs for up to 42 days in classical nutritive solution conditions, without any specialized equipment. We foresee that these improvements will facilitate the characterization of RBCs derived from gene-edited HSPCs. KEY POINTSO_LIErythroid progenitors were differentiated into fully mature RBCs in a medium free of accessory cells C_LIO_LICultured RBCs can be stored up to 42 days in a standard nutritive solution C_LI

cell biology↗

bioRxiv2017

A marker-free co-selection strategy for high efficiency human genome engineering

Targeted genome editing using engineered nucleases facilitates the creation of bona fide cellular models for biological research and may be applied to human cell-based therapies. Broadly applicable and versatile methods for increasing the levels of gene editing in cell populations remain highly desirable due to the variable efficiency between distinct genomic loci and cell types. Harnessing the multiplexing capabilities of CRISPR-Cas9 and Cpf1 systems, we designed a simple and robust co-selection strategy for enriching cells harboring either nuclease-driven non-homologous end joining (NHEJ) or homology-directed repair (HDR) events. Selection for dominant alleles of the endogenous sodium-potassium pump (Na+,K+-ATPase) that render cells resistant to ouabain is used to enrich for custom modifications at another unlinked locus of interest, effectively increasing the recovery of engineered cells. The process was readily adaptable to transformed and primary cells, including hematopoietic stem and progenitor cells (HSPCs). The use of universal CRISPR reagents and a commercially available small molecule inhibitor streamlines the incorporation of marker-free genetic changes in human cells.

molecular biology↗