Biology subjects

Pedro-Cos, L.

Publications and source records attributed to Pedro-Cos, L..

3 recordsLinked to original sources

bioRxiv2026

Defensive lipid droplets are PUFA reservoirs driving bacterial clearance and inflammation

Lipid droplets (LDs) rapidly form in infected cells to participate in the defence against microbes. Here, we investigate the involvement of LD lipids in these immune responses. Comparative shotgun and targeted lipidomics demonstrate that in vivo host LDs accumulate polyunsaturated fatty acids (PUFAs). PUFAs arrive at cells from the bloodstream to be further metabolised into complex PUFAs accrued by LD-triglycerides and -phospholipids. Host lipid metabolism is transcriptionally controlled by rapid, transient, and intricate immune programs initiated by pathogen-associated molecular patterns and relayed by cytokines such as interferons (type I and II), interleukins (IL-1{beta}), and tumour necrosis factor. When this lipid and signalling environment is reproduced in cultured macrophages, newly formed LDs accumulate defensive proteins, coordinate the synthesis of complex PUFAs, and become PUFA reservoirs and suppliers. Among LD-PUFAs, the {omega}-6 arachidonic acid is the most actively metabolised during the initial phases of innate immunity. Released from LDs by adipose triglyceride lipase, arachidonic acid is used by macrophages for prostaglandin synthesis, bacterial phagocytosis, and elimination of microbes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=163 HEIGHT=200 SRC="FIGDIR/small/711356v2_ufig1.gif" ALT="Figure 1"> View larger version (107K): org.highwire.dtl.DTLVardef@14d65eorg.highwire.dtl.DTLVardef@5ecc1org.highwire.dtl.DTLVardef@fa99e5org.highwire.dtl.DTLVardef@8d9632_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

A platform for high-throughput and ultrasensitive immunopeptidomics

Mass spectrometry (MS)-based immunopeptidomics is a powerful approach for untargeted discovery of peptides presented on major histocompatibility complex (MHC) molecules, which can guide the selection of vaccine antigens and immunotherapy targets. First-generation immunopeptidomics workflows require processing of hundreds of millions of cells using lengthy, manual procedures. More recent approaches focus on increasing either sensitivity or throughput, but rarely combine both aspects. Here, we describe a semi-automated immunopeptidomics platform that combines high sensitivity with high throughput by implementing highly optimized conditions for immunoprecipitation, elution and purification of MHC class I and II peptides on a 96-well positive-pressure device. Upon analysis of 25% of the eluate from 16 million cells, our workflow identified over 13,500 MHC I and 6,000 MHC II peptides on a timsTOF SCP mass spectrometer, operating in DDA-PASEF mode. Exploring the sensitivity limits of our platform, we identified over 1,000 MHC I peptides from as few as 20,000 JY cells. Validating the platforms performance for quantitative biological discovery, we report the identification of known and novel bacterial immunopeptides from U937 macrophages infected with Listeria monocytogenes or Bacillus Calmette-Guerin (BCG). Together, our optimized immunopeptidomics platform enables robust immunopeptide detection from lower-input samples in a high-throughput fashion, enabling its use for biological applications where sample amounts are limiting.

immunology↗

bioRxiv2021

De novo synthesized polyunsaturated fatty acids operate as both host immunomodulators and nutrients for Mycobacterium tuberculosis

Successful control of Mycobacterium tuberculosis (Mtb) infection by macrophages relies on immunometabolic reprogramming, where the role of fatty acids (FAs) remains poorly understood. Recent studies unraveled Mtbs capacity to acquire saturated and monounsaturated FAs via the Mce1 importer. However, upon activation macrophages produce polyunsaturated FAs (PUFAs), mammal-specific FAs mediating the generation of key immunomodulatory eicosanoids. Here, we asked whether de novo synthesis of PUFAs is modulated in Mtb-infected macrophages and benefits host or pathogen. Quantitative lipidomics revealed that Mtb infection activates the early PUFA biosynthetic pathway for production of eicosanoids. While PUFA synthesis blockade significantly impaired the inflammatory and antimicrobial responses of infected macrophages, it had no effect on Mtb growth in vivo. Using a click-chemistry approach, we found that Mtb efficiently imports PUFAs of the {omega}6 subset via Mce1 in axenic culture, including the eicosanoid precursor arachidonic acid (AA). Notably, Mtb preferentially internalized AA over all other FAs within infected macrophages, but here Mtbs import of AA was largely Mce1-independent and correlated with elevated AA uptake by host cells. Together, these findings reveal AA as a major FA substrate for intracellular Mtb. They suggest that Mtbs hijacking of host-derived AA may counteract its stimulatory effect on anti-mycobacterial immune responses.

immunology↗