Biology subjects

Sester, D. P.

Publications and source records attributed to Sester, D. P..

3 recordsLinked to original sources

bioRxiv2022

High dimensional flow cytometric analysis reveals distinct NK cell subsets but conserved response to cytokine stimulation in umbilical cord blood and adult peripheral blood

Adoptive cellular therapies using Natural Killer (NK) cells are of growing interest. NK cells can be obtained from various sources, including umbilical cord blood (UCB) and adult peripheral blood (APB). Understanding the diversity of NK cell populations and their receptor expression in both UCB and APB will guide future therapeutic designs. In this study, we used a 20-colour flow cytometry panel to compare unstimulated and cytokine-activated UCB and APB NK cells. Our analysis showed that UCB NK cells express slightly higher levels of the immune checkpoints PD-1, TIGIT and CD96 compared to their APB counterparts. Unsupervised hierarchical clustering and principal component analyses revealed previously unappreciated differences in NK cell populations from UCB and APB. UCB was characterised by an enrichment in CD56neg as well as mature NKp46neg and CD56+CD16+ NK cell populations whereas CD57+ terminally differentiated NK cells with variable expression of KIRs and CD16 were found in APB. These populations were conserved following two-days of IL-15 culture as well as overnight stimulation with IL-12, IL-15, and IL-18. Interestingly, cytokine stimulation was associated with the up-regulation of LAG-3 and DNAM-1 together with the downregulation of NKG2D, TIGIT and CD16 on multiple NK cell subsets in both UCB and APB. TIM-3 was also up-regulated with activation, but only in UCB. Overall, our data indicate that NK cells in UCB have a more immature phenotype than APB NK cells and UCB NK cells might be more amenable to immune checkpoint therapy.

immunology↗

bioRxiv2022

A Microtubule Mechanostat Enables Cells to Navigate Confined Environments

Cells migrating through complex 3D environments experience considerable physical challenges including tensile stress and compression. To move, cells need to resist these forces whilst also squeezing the large nucleus through confined spaces. This requires highly coordinated cortical contractility. Microtubules can both resist compressive forces and sequester key actomyosin regulators to ensure appropriate activation of contractile forces. Yet, how these two roles are integrated to achieve nuclear transmigration in 3D is largely unknown. Here, we demonstrate that compression triggers reinforcement of a dedicated microtubule structure at the rear of the nucleus by the mechanoresponsive recruitment of CLASPs (cytoplasmic linker-associated proteins) which dynamically strengthens and repairs the lattice. These reinforced microtubules form the mechanostat: an adaptive feedback mechanism that allows the cell to both withstand compressive force and spatiotemporally organise contractility signalling pathways. The microtubule mechanostat facilitates nuclear positioning and coordinates force production to enable the cell to pass through constrictions. Disruption of the mechanostat imbalances cortical contractility, stalling migration and ultimately resulting in catastrophic cell rupture. Our findings reveal a new role for microtubules as cellular sensors which detect and respond to compressive forces, enabling movement and ensuring survival in mechanically demanding environments. One Sentence SummaryMechanically tuned microtubules form a mechanostat to coordinate contractility and nuclear positioning in confined migration.

cell biology↗

bioRxiv2021

Fragmentation of macrophages during isolation confounds analysis of single cell preparations from mouse hematopoietic tissues

Mouse hematopoietic tissues contain abundant and heterogeneous populations of tissue-resident macrophages attributed trophic functions in control of immunity, hematopoiesis and bone homeostasis. A systematic strategy to characterise macrophage subsets in mouse bone marrow (BM), spleen and lymph node, unexpectedly revealed macrophage surface marker staining typically emanated from membrane-bound subcellular remnants associated with unrelated cell types. Remnant-restricted macrophage-specific membrane markers, cytoplasmic fluorescent reporters and mRNA were all detected in non-macrophage cell populations including isolated stem and progenitor cells. The profile of macrophage remnant association reflects adhesive interactions between macrophages and other cell types in vivo. Applying this knowledge, reduced macrophage remnant attachment to BM granulocytes in Siglec1 deficient mice was associated with compromised emergency granulocytosis, revealing a function for Siglec1-dependent granulocyte-macrophage interactions. Analysis of published RNA-seq data for purified macrophage and non-macrophage populations indicates that macrophage fragmentation is a general phenomenon that confounds bulk and single cell analysis of disaggregated tissues.

immunology↗