Biology subjects

Capolupo, L.

Publications and source records attributed to Capolupo, L..

7 recordsLinked to original sources

bioRxiv2025

The lipidomic architecture of the mouse brain

Lipids are fundamental components of the brain, crucial for synaptic transmission and signal propagation. Altered brain lipid composition is associated with common and rare neuropathologies, yet, the spatial organization of the mammalian brain lipidome remains insufficiently characterized compared to other modalities1-8. Here, we mapped the membrane lipid architecture of the adult mouse brain at micrometric scale, across sexes, and during pregnancy. This Lipid Brain Atlas reveals that lipids define a fine-grained biochemical structure that aligns with functional anatomy. Membrane lipid spatial heterogeneity clusters into territories, which we termed lipizones. Lipizones partially mirror cell type territories, but also capture distal axon terminals. Through lipizones, (i) we reveal the organizing principles of the gray matter lipidome, related to connectivity and cytoarchitecture; (ii) we discover a new axis of oligodendrocyte heterogeneity in the white matter; (iii) and we find biochemical zonation in the choroid plexus and in the ventricular walls. We show that this lipidomic architecture can adapt to changing physiological needs. In the brain of pregnant females, the white matter is metabolically activated and the outer cortex is reorganized. These results are a foundational resource (https://lbae-v2.epfl.ch/), poised to reshape our understanding of lipids in brain development, physiology, and pathology.

systems biology↗

bioRxiv2024

Unified Mass Imaging Maps the Lipidome of Vertebrate Development

Embryo development entails the formation of anatomical structures with distinct biochemical compositions. Compared with the wealth of knowledge on gene regulation, our understanding of metabolic programs operating during embryogenesis is limited. Mass spectrometry imaging (MSI) has the potential to map the distribution of metabolites across embryo development. Here, we established an analytical framework for the joint analysis of large MSI datasets that allows for the construction of multi-dimensional metabolomic atlases. Employing this framework, we mapped the 4D distribution of over a hundred lipids at quasi-single-cell resolution in Danio rerio embryos. We discovered metabolic trajectories that unfold in concert with morphogenesis and revealed spatially organized biochemical coordination overlooked by bulk measurements. Interestingly, lipid mapping revealed unexpected distributions of sphingolipid and triglyceride species, suggesting their involvement in pattern establishment and organ development. Our approach empowers a new generation of whole-organism metabolomic atlases and enables the discovery of spatially organized metabolic circuits.

systems biology↗

bioRxiv2024

Actin dynamics sustains spatial gradients of membrane tension in adherent cells

Tension propagates in lipid bilayers over hundreds of microns within milliseconds, precluding the formation of tension gradients. Nevertheless, plasma membrane tension gradients have been evidenced in migrating cells and along axons. Here, using a fluorescent membrane tension probe, we show that membrane tension gradients exist in all adherent cells, whether they migrate or not. Non-adhering cells do not display tension gradients. We further show that branched actin increases tension, while membrane-to-cortex attachments facilitate its propagation. Tension is the lowest at the edge of adhesion sites and highest at protrusions, setting the boundaries of the tension gradients. By providing a quantitative and mechanistic basis behind the organization of membrane tension gradients, our work explains how they are actively sustained in adherent cells.

cell biology↗

bioRxiv2022

Anthrax intoxication reveals that ER-Golgi membrane contact sites control the formation of plasma membrane lipid nanodomains

To promote infections, pathogens exploit host cell machineries including structural elements of the plasma membrane. Studying these interactions and identifying involved molecular players is an ideal way to gain insights into the fundamental biology of the host cell. Here, using the anthrax toxin, we screened a 1500-gene library of regulatory, cell surface, and membrane trafficking genes for their involvement in the intoxication process. We found that the ER-Golgi-localized proteins TMED2 and TMED10 are required for toxin oligomerization at the cell surface, an essential step for anthrax intoxication that depends on localization to cholesterol-rich lipid nanodomains. Further biochemical, morphological and mechanistic analyses showed that TMED2 and TMED10 are essential components of a multiprotein supercomplex that operates exchange of both cholesterol and ceramides at ER-Golgi membrane contact sites. Overall, this study of anthrax intoxication led to the discovery that lipid compositional remodelling at ER-Golgi interfaces fully controls the formation of functional membrane nanodomains at the cell surface.

cell biology↗

bioRxiv2021

Sphingolipid Control of Fibroblast Heterogeneity Revealed by Single-Cell Lipidomics

Human cells produce thousands of lipids that impact a wide range of biological processes in ways we are only starting to characterize. The cellular composition in lipids changes during differentiation events and also varies across individual cells of the same type. Yet, the precise differences in lipid composition that directly affect cell phenotypes remain unknown. Here we have measured the lipidomes and transcriptomes of individual human dermal fibroblasts by coupling high-resolution mass spectrometry imaging to single-cell transcriptomics. We found that the cell-to-cell variation of specific lipid metabolic pathways contributes to the establishment of cell states involved in wound repair and in skin cancer growth. Sphingolipid composition defined fibroblast subpopulations while sphingolipid metabolic rewiring drove cell state transitions. These data uncover a role for cell-to-cell lipid heterogeneity in the determination of cell states and reveal a new regulatory component to the homeostasis and self-organization of multicellular systems.

biochemistry↗

bioRxiv2020

Regulated compartmentalization of enzymes in Golgi by GRASP55 controls cellular glycosphingolipid profile and function

Glycans are important regulators of cell and organismal physiology. This requires that the glycan biosynthesis be controlled to achieve specific cellular glycan profiles. Glycans are assembled in the Golgi apparatus on secretory cargoes that traverse it. The mechanisms by which the Golgi apparatus ensures cell- and cargo-specific glycosylation remain obscure. We investigated how the Golgi apparatus regulates glycosylation by studying biosynthesis of glycosphingolipids, glycosylated lipids with critical roles in signalling and differentiation. We identified the Golgi matrix protein GRASP55 as a controller of sphingolipid glycosylation by regulating the compartmentalized localization of key sphingolipid biosynthetic enzymes in the Golgi. GRASP55 controls the localization of the enzymes by binding to them and regulating their entry into peri-Golgi vesicles. Impairing GRASP55-enzyme interaction decompartmentalizes these enzymes, changes the substrate flux across competing glycosylation pathways that results in alteration of the cellular glycosphingolipid profile. This GRASP55 regulated pathway of enzyme compartmentalization allows cells to make cell density-dependent adaptations in glycosphingolipid biosynthesis to suit cell growth needs. Thus, the Golgi apparatus controls the cellular glycan (glycosphingolipid) profile by governing competition between biosynthetic reactions through regulated changes in enzyme compartmentalization.

cell biology↗

bioRxiv2019

Retrograde Transport of Golgi Enzymes by GOLPH3 Across Maturing Cisternae Regulates Glycan Assembly on Sphingolipids and CellGrowth

Glycans are ubiquitous sugar polymers with major biological functions that are assembled by glyco-enzymes onto cargo molecules during their transport through the Golgi complex. How the Golgi determines glycan assembly is poorly understood. By relying on the Golgi cisternal maturation model and using the glyco-enzyme adaptor and oncoprotein GOLPH3 as a molecular tool, we define the first example of how the Golgi controls glycosylation and associated cell functions. GOLPH3, acting as a component of the cisternal maturation mechanism, selectively binds and recycles a subset of glyco-enzymes of the glycosphingolipid synthetic pathway, hinders their escape to the lysosomes and hence increases their levels through a novel lysosomal degradation-regulated mechanism. This enhances the production of specific growth-inducing glycosphingolipids and reprograms the glycosphingolipid pathway to potentiate mitogenic signaling and cell proliferation. These findings unravel unforeseen organizing principles of Golgi-dependent glycosylation and delineate a paradigm for glycan assembly by the Golgi transport mechanisms. Moreover, they indicate a new role of cisternal maturation as a regulator of glycosylation, and outline a novel mechanism of action for GOLPH3-induced proliferation.

cell biology↗