Search bioRxiv⌕ Search

bioRxiv · 10.1101/2022.03.11.484029

Patterned apoptosis modulates local growth and tissue shape in a fast-growing epithelium

Abstract

What regulates organ size and shape remains one of the fundamental mysteries of modern biology. So far, research in this area has primarily focused on deciphering the regulation in time and space of growth and cell division, while the contribution of cell death has been much more neglected. This includes studies of the Drosophila wing imaginal disc, the prospective fly wing which undergoes massive growth during larval stage, and represents one of the best characterised systems for the study of growth and patterning. So far, it has been assumed that cell death was relatively neglectable in this tissue and as a result the pattern of growth was usually attributed to the distribution of cell division. Here, using systematic mapping and registration combined with quantitative assessment of clone size and disappearance, we show for the first time that cell death is not neglectable, and outline a persistent pattern of cell death and clone elimination in the disc. Local variation of cell death is associated with local variation of clone size, pointing to an impact of cell death on local growth which is not fully compensated by proliferation. Using morphometric analyses of adult wing shape and genetic perturbations, we provide evidence that patterned death affects locally and globally adult wing shape and size. This study describes a roadmap for accurate assessment of the contribution of cell death to tissue shape, and outlines for the first time an important instructive role of cell death in modulating quantitatively local growth and the morphogenesis of a fast-growing tissue.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Matamoro-Vidal, A., Cumming, T., Davidovic, A., Levayer, R.. 2022-03-14. Patterned apoptosis modulates local growth and tissue shape in a fast-growing epithelium. https://doi.org/10.1101/2022.03.11.484029

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Hyaluronic acid dynamics are regulated by neural crest cells and NEDD4 in the developing cardiac outflow tract valves

The extracellular matrix (ECM) is essential for cardiac valve development, with hyaluronic acid (HA) playing a critical role in cardiac cushion formation. While HA is required for atrioventricular valve development, its role in semilunar valve formation remains poorly understood. The ubiquitin ligase NEDD4 is essential for cardiac outflow tract development, particularly within cardiac neural crest cells, however its role in semilunar valve development has been unexplored. Here, we demonstrate that neural crest-specific deletion of NEDD4 in mice disrupts outflow tract valve development, resulting in abnormal leaflet number and morphology. Analysis of valve ECM revealed a specific reduction in HA within the neural crest-derived valve mesenchyme, while other ECM components such as fibronectin and versican remained unaffected. In contrast, deletion of NEDD4 in endocardium-derived valve mesenchyme did not alter HA abundance. Using NEDD4-deficient neural crest cells, we further demonstrate a cell-autonomous requirement for NEDD4 in regulating HA abundance, with in vitro evidence supporting impaired HA synthesis rather than increased turnover of HA in the ECM. Our findings identify a previously unrecognised role for NEDD4 in regulating HA synthesis in cardiac neural crest cells, revealing a cell-type-specific mechanism governing semilunar valve development and highlighting distinct cellular requirements for ECM regulation across cardiac valve populations.

developmental biology↗

Cxcr2 is required for ductal outgrowth and shapes the stromal microenvironment in postnatal mammary gland development

Mammary gland development requires coordinated signaling between epithelial and stromal compartments. While CXC chemokine receptor 2 (CXCR2) is known to regulate inflammatory and tissue remodeling processes in disease, including breast cancer, its role in mammary gland morphogenesis is not well understood. Here, we examined postnatal mammary gland development in germline Cxcr2 knockout mice. Loss of Cxcr2 resulted in delayed ductal outgrowth, reduced epithelial area, and altered stromal architecture, including decreased adipocyte size and increased collagen deposition, despite preserved branching organization. These defects occurred in the context of severe systemic immune dysregulation, marked by expansion of granulocytic populations and loss of adaptive immune cells. Together, our findings indicate that CXCR2 indirectly regulates mammary gland development through coordination between the epithelium and stroma, rather than acting through epithelial cell-intrinsic mechanisms. Because the same myeloid expansion, immune suppression, and collagen-rich stromal remodeling that CXCR2 controls during normal development are hallmarks of the pro-tumorigenic breast microenvironment, these findings establish CXCR2 as a regulator of the immune and stromal landscape of the mammary gland and provide a developmental framework for understanding its contributions to the breast tumor microenvironment.

developmental biology↗

Endogenous Mechanical Reporters Encode the Global Mechanical Landscape of Morphogenesis

Developmental systems usually comprise multiple genetically programmed morphogenetic events within a mechanically continuous environment, yet how individual processes interact and contribute to the overall mechanical landscape remains unknown. Here, we introduce the concept of mechanical reporter: endogenous tissues function as in situ probes of the embedded mechanical landscape. We exemplified cephalic furrow (CF) migration as a mechanical reporter in gastrulating Drosophila. Using optogenetics and genetics, we revealed that CF displacement reflects the combined effect of both force and tissue mechanical properties. By incorporating condition-specific mechanical landscape into a continuum minimal-response model, we developed a framework to quantitatively predict the reporter dynamics. Using different genetic mutants, we successfully decoded changes in the mechanical landscape from CF dynamics in gastrulating Drosophila. Overall, we established a predictive framework that uses CF dynamics to infer changes in the global mechanical landscape. Beyond this, the concept of mechanical reporter provides a general strategy for systematically understanding and decoding complex mechanical environments in living systems.

developmental biology↗