Biology subjects

Lucas, D.

Publications and source records attributed to Lucas, D..

4 recordsLinked to original sources

bioRxiv2023

Drought impact on phellem development: identification of novel gene regulators and evidence of photosynthetic activity

Quercus suber (cork oak) is a sustainably exploited forest resource, producing a unique renewable raw material known as cork. With drought events imposing a negative impact on tree vitality, we need more knowledge on the genetic and environmental regulation of cork development to protect the cork sector. We focused on characterizing long-term drought-induced molecular adaptations occurring in stems, and identifying key genetic pathways regulating phellem development. One-year-old cork oak plants were grown for 6 months under well-watered, or water-deficit (WD) conditions and main stems were targeted for histological characterization and transcriptomic analysis. WD treatment impaired secondary growth, by reducing meristem activity at both vascular cambium and phellogen. We analyzed the transcriptional changes imposed by WD in phellem, inner bark, and xylem, and found a global downregulation of genes related to cell division, differentiation, and cell wall biogenesis. Phellem and inner bark showed upregulation of photosynthesis-related genes, highlighting a determinant role of stem photosynthesis in the adaptation to long-term drought. We show that developing phellem cells contain chloroplasts and their abundance increases under WD. Finally, we propose new candidate regulatory genes involved in the regulation of phellogen activity and demonstrate the involvement of phellem in drought-induced bark photosynthesis in young plants. HighlightPhellem development in cork oak is impaired in drought adaptation, by negative regulation of cell division and differentiation programs, while photosynthesis is induced to contributing to CO2 recycling in the stem.

plant biology↗

bioRxiv2023

Macrophage epigenetic memories of early life injury drive neonatal nociceptive priming

The developing peripheral nervous and immune systems are functionally distinct from adults. These systems are vulnerable to early life injury, which influences outcomes related to nociception following subsequent injury later in life (i.e., "neonatal nociceptive priming"). The underpinnings of this phenomenon are largely unknown, although previous work indicates that macrophages are epigenetically trained by inflammation and injury. We found that macrophages are both necessary and partially sufficient to drive neonatal nociceptive priming possibly due to a long-lasting epigenetic remodeling. The p75 neurotrophic factor receptor (NTR) was an important effector in regulating neonatal nociceptive priming through modulation of the inflammatory profile of rodent and human macrophages. This "pain memory" was long lasting in females and could be transferred to a naive host to alter sex-specific pain-related behaviors. This study reveals a novel mechanism by which acute, neonatal post-surgical pain drives a peripheral immune-related predisposition to persistent pain following a subsequent injury. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/528015v2_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@117ad6eorg.highwire.dtl.DTLVardef@17b4188org.highwire.dtl.DTLVardef@10b4d9borg.highwire.dtl.DTLVardef@1142094_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Resilient anatomy and local microplasticity of na&iumlve and stress hematopoiesis

The bone marrow has an extraordinary capacity to adjust blood cell production to meet physiological demands in response to insults. The spatial organization of normal and stress responses is largely unknown due to the lack of methods to visualize most steps of blood production. Here we develop strategies to image multipotent hematopoiesis, megakaryopoiesis, erythropoiesis, and lymphopoiesis in mice. We combine these with imaging of myelopoiesis1 to define the anatomy of hematopoiesis in homeostasis, after acute insults, and during geriatric age. Blood production takes place via long-range migration of multipotent progenitors away from stem cells. Lineage-committed progenitors are then serially recruited to blood vessels where they contribute to lineage-specific microanatomical structures, composed of progenitors and immature cells, which function as production lines for mature blood cells. This anatomy is durable and resilient to insults as it was maintained after hemorrhage, acute bacterial infection, and with aging. Production lines enable hematopoietic plasticity as they differentially -and selectively-modulate their numbers and output in response to acute insults and then return to homeostasis. In geriatric mice the number of production lines is maintained, but their microanatomy becomes permanently remodeled in a cell- and lineage-specific manner indicating chronic anatomical adaptations to hematopoietic aging. Our studies uncover the sophisticated and durable anatomy of blood production -defined by distinct migratory behaviors depending on the maturation stage- and identify discrete microanatomical production lines that confer plasticity to hematopoiesis.

physiology↗

bioRxiv2020

Three-dimensional mapping identifies distinct vascular niches for myelopoiesis

In contrast to virtually all other tissues in the body the anatomy of differentiation in the bone marrow remains unknown. This is due to the lack of strategies to examine blood cell production in situ, which are required to better understand differentiation, lineage commitment decisions, and to define how spatial organizing cues inform tissue function. Here we developed imaging approaches to map all myeloid cells in whole bones and generated 3D atlases of granulocyte and monocyte/dendritic cell differentiation during homeostasis. We found that myeloid progenitors leave the hematopoietic stem cell niche during differentiation. Granulocyte and monocyte dendritic cell progenitors (MDP) do not interact, instead they localize to different sinusoids where they give rise to clusters of immature cells. MDP cluster with Ly6Clo monocytes and conventional dendritic cells; these localize to a unique subset of colony stimulating factor 1 (CSF1, the major regulator of monopoiesis1) -expressing sinusoids. Csf1 deletion in the vasculature disrupted the MDP clusters and their interaction with sinusoids, leading to reduced MDP numbers and differentiation ability, with subsequent loss of peripheral Ly6Clo monocytes and dendritic cells. These data indicate that there is a specific spatial organization of definitive hematopoiesis and that local cues produced by distinct blood vessels are responsible for this organization. These maps provide a blueprint for in situ analyses of hematopoiesis in blood disorders.

immunology↗