Biology subjects

Barillas-Mury, C.

Publications and source records attributed to Barillas-Mury, C..

8 recordsLinked to original sources

bioRxiv2025

Cell-specific responses of Anopheles gambiae fat body to blood feeding and infection at a single nuclei resolution

The mosquito fat body plays key roles in metabolism and immunity, yet its cellular diversity and functional specialization remain unclear. We characterized the Anopheles gambiae fat body and associated cells, examining their responses to blood feeding, bacterial infection, and immune priming following Plasmodium berghei infection, at single-cell resolution. We analyzed 97,650 nuclei from the female mosquitos abdominal body wall and identified seven major cell types. Fat body trophocytes were the most abundant ([~]85% of cells), while sessile hemocytes represented 7.4% of cells. Trophocytes consisted of five subpopulations, including basal (T1, T2), metabolic-enriched (T3), immune-responsive (T4), and a vitellogenic population (T5) exclusive to blood-fed females. T4 trophocytes exhibited constitutive expression of immune genes, while multiple cell types, including other trophocytes, hemocytes, and epidermal epithelial cells, responded to a systemic bacterial challenge. Oenocytes (1.1% of cells) induced the expression of enzymes involved in the biosynthesis of lipids in response to immune priming. Blood feeding triggered massive transcriptomic changes, with a strong induction of vitellogenin and multiple genes involved in DNA replication, consistent with trophocyte endoreplication and metabolic reprogramming. Interestingly, vitellogenin mRNA was expressed only in the first layer of trophocytes facing the hemolymph and had an apical subcellular localization. These findings provide a high-resolution atlas of fat body and associated cells, revealing specialized roles in immunity and reproduction and offering insights into how mosquitoes coordinate metabolic and immune functions at the cellular level.

molecular biology↗

bioRxiv2025

High-Resolution Proteomics Unveils Salivary Gland Disruption and Saliva-Hemolymph Protein Exchange in Plasmodium-Infected Mosquitoes

Plasmodium sporozoites, the stage that initiates a malaria infection, must invade the mosquito salivary glands (SGs) before transmitting to a vertebrate host. However, the effects of sporozoite invasion on salivary gland physiology and saliva composition remain largely unexplored. We examined the impact of Plasmodium infection on Anopheles gambiae salivary glands using high-resolution proteomics, gene expression, and morphological analysis. The data revealed differential expression of various proteins, including the enrichment of humoral proteins in infected salivary glands originating from the hemolymph. These proteins diffused into the SGs due to structural damage caused by the sporozoites during invasion. Conversely, saliva proteins diffused out into the circulation of infected mosquitoes. Moreover, infection altered saliva protein composition, as shown by proteomes from saliva collected from mosquitoes infected by P. berghei or P. falciparum, revealing a significant reduction of immune proteins compared to uninfected mosquitoes. This reduction is likely due to the association of these proteins with the surface of sporozoites within the mosquito salivary secretory cavities. The saliva protein profiles from mosquitoes infected with both Plasmodium species were remarkably similar, suggesting a conserved interaction between sporozoites and salivary glands. Our results provide a foundation for understanding the molecular interactions between Plasmodium sporozoites and mosquito salivary glands.

microbiology↗

bioRxiv2023

Mosquito midgut stem cell cellular defense response limits Plasmodium parasite infection

A novel cellular response of midgut progenitors (stem cells and enteroblasts) to Plasmodium berghei infection was investigated in Anopheles stephensi. The presence of developing oocysts triggers proliferation of midgut progenitors that is modulated by the Jak/STAT pathway, and proportional to the number of oocysts on individual midguts. The percentage of parasites in direct contact with enteroblasts increases over time, as progenitors proliferate. Enhancing proliferation of progenitors significantly decreases oocyst numbers, while limiting proliferation increases oocyst survival. Live imaging revealed that enteroblasts interact directly with oocysts and eliminate them. Midgut progenitors sense the presence of Plasmodium oocysts and mount a cellular defense response that involves extensive proliferation and tissue remodeling, followed by oocysts lysis and phagocytosis of parasite remnants by enteroblasts. One-Sentence SummaryMosquito midgut stem cells detect Plasmodium parasites, proliferate and enteroblasts actively eliminate oocysts.

immunology↗

bioRxiv2022

Genetic exchange in Leishmania is facilitated by IgM natural antibodies

Host factors mediating Leishmania genetic exchange are not well defined. Here, we demonstrate that IgM antibodies, but not IgG or IgA, facilitate parasite genetic hybridization in vitro and in vivo. IgM induces the gradual and transient formation of a structured parasite clump in a process essential for L. major and L. tropica hybridization in vitro. Parasite hybrids and 3-nucleated parasites were observed inside this structure, named the Leishmania mating clump. IgM was also required for or significantly increased Leishmania hybrid formation in vivo. At minimum, we observed a 12-fold increase in the proportion of hybrids recovered from sand flies provided a second blood meal containing IgM compared to controls. Notably, genetic backcross events in sand flies were only observed in the presence of IgM, and were reproducibly recovered, reinforcing the relevance of IgM for Leishmania genetic exchange in vivo. The in vitro and in vivo Leishmania crosses from these studies resulted in full genome hybrids. Leishmania co-option of a host antibody to facilitate mating in the insect vector establishes a new paradigm of parasite-host-vector coevolution that promotes parasite diversity and fitness through genetic exchange.

microbiology↗

bioRxiv2022

The Aedes aegypti peritrophic matrix controls arbovirus vector competence through HPx1, a heme induced peroxidase.

Aedes aegypti mosquitoes are the main vectors of arboviruses. The peritrophic matrix (PM) is an extracellular layer that surrounds the blood bolus and acts as an immune barrier that prevents direct contact of bacteria with midgut epithelial cells during blood digestion. Here, we describe a heme-dependent peroxidase, hereafter referred to as heme peroxidase 1 (HPx1). HPx1 promotes PM assembly and antioxidant ability, modulating vector competence. Mechanistically, the heme presence in a blood meal induces HPx1 transcriptional activation mediated by the E75 transcription factor. HPx1 knockdown increases midgut reactive oxygen species (ROS) production by the DUOX NADPH oxidase. Elevated ROS levels reduce microbiota growth while enhancing epithelial mitosis, a response to tissue damage. However, simultaneous HPx1 and DUOX silencing was not able to rescue bacterial population growth, as explained by increased expression of antimicrobial peptides (AMPs), which occurred only after double knockdown. This result revealed hierarchical activation of ROS and AMPs to control microbiota. HPx1 knockdown produced a 100-fold decrease in Zika and Dengue 2 midgut infection, demonstrating the essential role of the mosquito PM in the modulation of arbovirus vector competence. Our data show that the PM connects blood digestion to midgut immunological sensing of the microbiota and viral infections.

microbiology↗

bioRxiv2021

Malaria parasite evades mosquito immunity by glutaminyl cyclase mediated protein modification

Glutaminyl cyclase (QC) modifies N-terminal glutamine or glutamic acid residues of target proteins into cyclic pyroglutamic acid (pGlu). Here, we report the biochemical and functional analysis of Plasmodium QC. We show that Plasmodium sporozoites of QC-null mutants are recognized by the mosquito immune system and melanized when they reach the hemocoel. Sporozoite numbers in salivary glands are also reduced in mosquitoes infected with QC-null or QC catalytically-dead mutants. This phenotype can be rescued by genetic complementation or by disrupting mosquito hemocytes or melanization immune responses. Mutation of a single QC-target glutamine of the major sporozoite surface protein (CSP) also results in immune recognition of sporozoites. These findings reveal QC-mediated post-translational modification of surface proteins as a major mechanism of mosquito immune evasion by Plasmodium sporozoites.

microbiology↗

bioRxiv2020

Proliferation of DBLOX Peroxidase-Expressing Oenocytes Maintains Innate Immune Memory in Primed Mosquitoes

Immune priming in Anopheles gambiae mosquitoes following infection with Plasmodium parasites is mediated by the systemic release of a hemocyte differentiation factor (HDF), a complex of lipoxin A4 bound to Evokin, a lipid carrier. HDF increases the proportion of circulating granulocytes and enhances mosquito cellular immunity. We found that Evokin is constitutively produced by hemocytes and fat-body cells, but expression increases in response to infection. Insects synthesize lipoxins, but lack lipoxygenases. Here, we show that the Double Peroxidase (DBLOX) enzyme, present in insects but not in vertebrates, is essential for HDF synthesis. DBLOX is highly expressed in oenocytes in the fat body tissue, and these cells proliferate in response to Plasmodium challenge. We provide direct evidence that modifications mediated by the histone acetyltransferase AgTip60 (AGAP01539) are essential for sustained oenocyte proliferation, HDF synthesis and immune priming. We propose that oenocytes function as a population of "memory" cells that continuously release lipoxin to orchestrate and maintain a broad, systemic and long-lasting state of enhanced immune surveillance.

immunology↗

bioRxiv2020

Mosquito cellular immunity at single-cell resolution

Insect hemocytes are the functional equivalents of leukocytes and limit the capacity of mosquitoes to transmit human pathogens through phagocytosis, encapsulation, secretion of immune factors and immune priming (1, 2). Here we profile the transcriptomes of 8506 hemocytes of Anopheles gambiae and Aedes aegypti, two important mosquito vectors. Blood feeding, infection with malaria parasites and other immune challenges reveal a previously unknown functional diversity of hemocytes, with different types of granulocytes expressing distinct and evolutionarily conserved subsets of effector genes. A new cell type, which we term megacyte, is defined in Anopheles by a unique transmembrane protein marker (TM7318) and high expression of LPS-Induced TNF-alpha transcription factor 3 (LL3). Knock-down experiments indicate that LL3 mediates hemocyte differentiation during immune priming. We identify two main hemocyte lineages and find evidence of proliferating granulocyte populations. We validate our analysis with RNA in-situ hybridization and highlight the mobilization of sessile hemocytes into circulation upon infection. Our data (https://hemocytes.cellgeni.sanger.ac.uk/) provide the first atlas of medically relevant invertebrate immune cells at single cell resolution. It provides an important resource for invertebrate immunology by identifying cellular events that underpin mosquito immunity to malaria infection.

immunology↗