Biology subjects

Villa, M.

Publications and source records attributed to Villa, M..

11 recordsLinked to original sources

bioRxiv2026

Structural studies of the C-terminal cysteine-rich domain of Aedes albopictus vitellogenin reveal an evolutionarily divergent, monomeric C-terminal cysteine knot (CTCK) architecture

Vitellogenins are essential transport lipoproteins and precursors to egg-yolk proteins in oviparous species. Several molecular structure studies have elucidated most of their multi-domain organization, yet the structure and function of their C-terminal cysteine knot (CTCK) domain have remained largely elusive. In this study, we present the 1.2 [A] resolution crystal structure of the recombinant CTCK domain from a vitellogenin isoform of the mosquito Aedes albopictus (Vg-CTCK). The molecular architecture reveals a CTCK fold defined by two antiparallel beta sheets stabilized by three intramolecular disulfide bonds, featuring a unique 12-amino acid insertion shaping an alpha helix positioned between the two main beta sheets. Analysis of the crystal packing and biophysical characterization in solution consistently confirms that recombinant Vg-CTCK is monomeric. To validate these findings in a native context, we employed ex vivo cross-linking mass spectrometry (XL-MS) on intact mosquito ovaries, which corroborated the molecular architecture of the Vg-CTCK observed in the crystal structure and highlighted the absence of inter-molecular cross-links. Collectively, our data highlight an evolutionarily divergent, monomeric assembly for the mosquito Vg-CTCK domain, challenging previous hypotheses that suggested this domain might facilitate vitellogenin oligomerization.

molecular biology↗

bioRxiv2025

B cell/adipocyte crosstalk drives pro-fibrotic macrophage migration and polarisation in Crohn`s disease-associated, inflamed adipose tissue

During Crohns disease (CD), hyperplasia of the mesenteric white adipose tissue (WAT), called creeping fat (CrF), is associated with the accumulation of immune cells. We here investigated whether B cell infiltration and their interaction with adipocytes influence inflammation and fibrosis of CD-associated adipose tissue. Analysing CrF of CD patients as well as WAT from a mouse model of intestinal inflammation, we found an accumulation of B cells and pro-fibrotic, M2-like macrophages. Depleting B cells through anti-CD20 antibody treatment diminished M2-like macrophage accumulation in inflamed mouse WAT. Mechanistically, we found that the B cell/adipocyte co-cultures led to elevated secretion of monocyte chemoattractant protein-1 (MCP-1) by primary adipocytes, in part due to TNF-a secretion by activated B cells. Adipocyte-derived MCP-1 resulted in enhanced macrophage migration. Furthermore, the supernatants of the B cell/adipocyte co-culture promoted pro-fibrotic, M2-like macrophage polarization in vitro, correlating with elevated levels of lactate. Single-cell RNA sequencing of human CrF and mouse WAT supported our in vitro findings suggesting that the B cell/adipocyte crosstalk supports a lactate-rich, inflammatory adipose tissue niche. Taken together, our results provide evidence for a crucial role of the B cell/adipocyte crosstalk to CD-associated adipose tissue inflammation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/664132v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@15de8f9org.highwire.dtl.DTLVardef@6a6873org.highwire.dtl.DTLVardef@1ef7a22org.highwire.dtl.DTLVardef@13b89a4_HPS_FORMAT_FIGEXP M_FIG C_FIG One Sentence SummaryO_LIB cells and pro-fibrotic macrophages accumulate in IBD-associated, inflamed adipose tissue C_LIO_LIB cell depletion in a mouse model reduces pro-fibrotic macrophage accumulation in IBD-associated, inflamed adipose tissue C_LIO_LIB cell/adipocyte crosstalk promotes B cell activation and MCP-1 secretion by adipocytes C_LIO_LIAdipocyte-derived MCP-1 promotes migration of macrophages C_LIO_LIB cell/adipocyte crosstalk provides a lactate-rich, inflammatory environment which likely drives pro-fibrotic macrophage polarisation C_LI

immunology↗

bioRxiv2025

ECgo: All-Optical Induction of Single Endothelial Cell Injury and Capillary Occlusion in the Brain

The ability to induce endothelial cell (EC) damage in the mouse brain with high spatial precision is invaluable for mechanistic studies of brain capillary injury and repair. Here, we introduce an optical method, termed ECgo, that utilizes a new two-photon-excitable porphyrin-based photosensitizer (Ps2P) to selectively obliterate single ECs within the brain microvascular network. Using the developed approach, we were able to induce occlusions of single capillaries with high spatiotemporal control, while preserving the surrounding tissue. Combined with longitudinal two-photon imaging, ECgo enables studies of morphological and functional consequences of targeted single capillary EC injury in vivo under healthy and diseased conditions. SIGNIFICANCE STATEMENTBrain capillary injury is a common feature of aging and many neurological disorders. While a single capillary lesion may appear inconsequential, the cumulative effect of repeated and spatially dispersed capillary insults can lead to substantial brain dysfunction. Understanding how single capillary injuries contribute cumulatively to long-term brain damage requires tools that can precisely target individual capillaries in the living brain. Here, we introduce an optical method that uses a new light-activatable compound to selectively injure single brain capillaries with high spatial accuracy. Our method enables detailed, longitudinal studies of capillary repair, blood flow recovery, local oxygen dynamics, and glial responses following microvascular injury.

neuroscience↗

bioRxiv2023

Evolutionary signatures of human cancers revealed via genomic analysis of over 35,000 patients

By leveraging the ever-increasing availability of cancer omics data and the continuous advances in cancer data science and machine learning, we have discovered the existence of cancer type-specific evolutionary signatures associated with different disease outcomes. These signatures represent "favored trajectories" of acquisition of driver mutations that are repeatedly detected in patients with similar prognosis. In this work, we present a novel framework named ASCETIC (Agony-baSed Cancer EvoluTion InferenCe) that extracts such signatures from NGS experiments generated by different technologies such as bulk and single-cell sequencing data. In our study, we applied ASCETIC to (i) single-cell sequencing data from 146 patients with distinct myeloid malignancies and bulk whole-exome sequencing data from 366 acute myeloid leukemia patients, (ii) multi-region sequencing data from 100 early-stage lung cancer patients from the TRACERx project, (iii) whole-exome/genome sequencing data from more than 10,000 Pan-Cancer Atlas samples, and (iv) targeted bulk sequencing data from more than 25,000 MSK-MET metastatic patients (both datasets including multiple cancer types). As a result, we extracted different cancer (sub)type-specific single-nucleotide variants evolutionary signatures associated with clusters of patients with statistically significant different prognoses. In addition, we conducted several validations using diverse and previously unexplored datasets to evaluate the reliability and applicability of the evolutionary signatures extracted by ASCETIC. Such analyses provided evidence of the robustness and generalizability of the identified evolutionary patterns.

genetics↗

bioRxiv2023

Prostaglandin E2 controls the metabolic adaptation of T cells to the intestinal microenvironment

Immune cells must adapt to different environments during the course of an immune response. We studied the adaptation of CD8+ T cells to the intestinal microenvironment and how this process shapes their residency in the gut. CD8+ T cells progressively remodel their transcriptome and surface phenotype as they acquire gut residency, and downregulate expression of mitochondrial genes. Human and mouse gut-resident CD8+ T cells have reduced mitochondrial mass, but maintain a viable energy balance to sustain their function. We found that the intestinal microenvironment is rich in prostaglandin E2 (PGE2), which drives mitochondrial depolarization in CD8+ T cells. Consequently, these cells engage autophagy to clear depolarized mitochondria, and enhance glutathione synthesis to scavenge reactive oxygen species (ROS) that result from mitochondrial depolarization. Impairing PGE2 sensing promotes CD8+ T cell accumulation in the gut, while tampering with autophagy and glutathione negatively impacts the T cell population. Thus, a PGE2-autophagy-glutathione axis defines the metabolic adaptation of CD8+ T cells to the intestinal microenvironment, to ultimately influence the T cell pool.

immunology↗

bioRxiv2022

Resident T cells orchestrate adipose tissue remodeling in a site peripheral to infection

Infection with helminth parasites can affect adiposity, but underlying mechanisms that regulate this process are unclear. We found that fat content of mesenteric adipose tissue (mAT) declined in mice during infection with gut-restricted parasitic worms. This was associated with the accumulation of metabolically activated, immunostimulatory cytokine- and extracellular matrix-secreting multipotent stromal cells, which had potential to differentiate into preadipocytes. Concomitantly, mAT became infiltrated with Th2 lymphocytes that took up long-term residence and responded to signals from stromal cells by producing stromal cell-stimulating cytokines, including Amphiregulin. Signals delivered by Amphiregulin to stromal cells were required for immunity to infection. Our findings reveal intricate intercellular communication between Th2 cells and adipocyte progenitors and link immunity to intestinal infection to T cell-dependent effects on the adipocyte lineage.

immunology↗

bioRxiv2022

Fitness costs and benefits in response to artificial artesunate selection in Plasmodium

AO_SCPLOWBSTRACTC_SCPLOWDrug resistance is a major issue in the control of malaria. Mutations linked to drug resistance often target key metabolic pathways and are therefore expected to be associated with biological costs. The spread of drug resistance depends on the balance between the benefits that these mutations provide in the drug-treated host and the costs they incur in the untreated host. The latter may therefore be expressed both in the vertebrate host and in the vector. Research on the costs of drug resistance focusses on interactions with vertebrate host, yet whether they are also expressed in the vector has been overlooked. In this study, we aim to identify the costs and benefits of resistance against artesunate (AS), one of the main artemisinin derivatives used in malaria-endemic countries. For this purpose, we compared different AS-selected lines of the avian malaria parasite Plasmodium relictum to their ancestral (unselected) counterpart. We tested their within host dynamics and virulence both in the vertebrate host and in its natural vector, the mosquito Culex quinquefasciatus. The within-host dynamics of the AS-selected lines in the treated birds was consistent with the phenotype of resistance described in human P. falciparum malaria: a clearance delay during the treatment followed by a recrudescence once the treatment was interrupted. In the absence of treatment, however, we found no significant costs of resistance in the bird. The results of the two experiments to establish the infectivity of the lines to mosquitoes point towards a decreased infectivity of the drug-selected lines as compared to the ancestral, reference one. We discuss the potential implication of these results on the spread of artesunate resistance in the field.

evolutionary biology↗

bioRxiv2020

The transmission-blocking effects antimalarial drugs revisited: mosquito fitness costs and sporontocidal effects of artesunate and sulfadoxine-pyrimethamine

Assays used to evaluate the transmission-blocking activity of antimalarial drugs are largely focused on their potential to inhibit or reduce the infectivity of gametocytes, the blood stages of the parasite that are responsible for the onward transmission to the mosquito vector. For this purpose, the drug is administered concomitantly with the gametocyte-infected blood, and the results are evaluated as the % reduction in the number of oocysts in the mosquito midgut. We report the results of a series of experiments that explore the transmission blocking potential of two key antimalarial drugs, artesunate (AS) and sulfadoxine-pyrimethamine (SP), when administered to mosquitoes already infected from a previous blood meal. For this purpose, uninfected mosquitoes and mosquitoes carrying a 6-day old Plasmodium relictum infection (early oocyst stages) are allowed to feed either on a drug-treated or an untreated host in a fully factorial experiment. This protocol allows us to bypass the gametocyte stages and establish whether the drugs are able to arrest the ongoing development of oocysts and sporozoites, as would be the case when a mosquito takes a post-infection treated blood meal. In a separate experiment, we also explore whether a drug-treated blood meal impacts key life history traits of the mosquito relevant for transmission, and if this depends on their infection status. Our results show that feeding on an AS- or SP-treated host has no epidemiologically relevant effects on the fitness of infected or uninfected mosquitoes. In contrast, when infected mosquitoes feed on an SP-treated host, we observe both a significant increase in the number of oocysts in the midgut, and a drastic decrease in both sporozoite prevalence (-30%) and burden (-80%) compared to the untreated controls. We discuss the potential mechanisms underlying these seemingly contradictory results and contend that, provided the results are translatable to human malaria, the potential epidemiological and evolutionary consequences of the current preventive use of SP in malaria-endemic countries could be substantial.

evolutionary biology↗

bioRxiv2020

Experimental evolution of virulence and associated traits in a Drosophila melanogaster - Wolbachia symbiosis

AO_SCPLOWBSTRACTC_SCPLOWEvolutionary theory predicts that vertically transmitted symbionts are selected for low virulence, as their fitness is directly correlated to that of their host. In contrast with this prediction, the Wolbachia strain wMelPop drastically reduces its Drosophila melanogaster host lifespan at high rearing temperatures. It is generally assumed that this feature is maintained because the D. melanogaster-wMelPop symbiosis is usually not exposed to environmental conditions in which the symbiont is virulent. To test this hypothesis, we submitted wMelPop-infected D. melanogaster lines to 17 generations of experimental evolution at a high temperature, while enforcing late reproduction by artificial selection. The fly survival was measured at different time points, as well as two traits that have been proposed to be causally responsible for wMelPop virulence: its relative density and the mean number of copies of octomom, an 8-genes region of the Wolbachia genome. We hypothesised that these conditions (high temperature and late reproduction) would select for a reduced wMelPop virulence, a reduced wMelPop density, and a reduced octomom copy number. Our results indicate that density, octomom copy number and virulence are correlated to each other. However, contrary to our expectations, we could not detect any reduction in virulence during the course of evolution. We discuss the significance of our results with respect to the evolutionary causes of wMelPop virulence.

evolutionary biology↗

bioRxiv2020

Polyamine Metabolism Regulates the T Cell Epigenome Through Hypusination

We report here a central role for polyamines in T cell differentiation and function. Deficiency in ornithine decarboxylase (ODC), a critical enzyme for polyamine synthesis, resulted in a profound failure of CD4+ T cells to adopt correct subset specification, underscored by ectopic expression of multiple cytokines and lineage-defining transcription factors across TH1, TH2, TH17, and Treg polarizing conditions, and enhanced colitogenic potential. T cells deficient in deoxyhypusine synthase (DHPS) or deoxyhypusine hydroxylase (DOHH), which sequentially utilize polyamines to generate hypusine, phenocopied Odc-deficient T cells, and mice in which T cells lacked Dhps or Dohh developed colitis. Polyamine-hypusine pathway enzyme deficiency caused widespread chromatin and transcriptional dysregulation accompanied by alterations in histone methylation, histone acetylation, and TCA cycle metabolites. Epigenetic modulation by 2-hydroxyglutarate, or histone acetyltransferase inhibition, restored CD4+ T cell subset specification. Thus, polyamine synthesis via hypusine is critical for maintaining the epigenome to focus TH cell subset fidelity.

immunology↗

bioRxiv2019

High-throughput isolation and culture of human gut bacteria with droplet microfluidics

Isolation and culture of gut bacteria enable testing for microbial roles in disease and may also lead to novel therapeutics. However, the diversity of human gut microbial communities (microbiota) impedes comprehensive experimental studies of individual bacterial taxa. Here, we combine advances in droplet microfluidics and high-throughput DNA sequencing to develop a platform for isolating and assaying microbiota members in picoliter droplets (MicDrop). MicDrop can be used to create millions of distinct bacterial colonies in a single experiment while using off-the-shelf parts compact enough to fit in an anaerobic chamber. In proof-of-concept experiments, we used the platform to characterize inter-individual metabolic variation among hundreds of polysaccharide-degrading gut bacteria from nine stool donors. We also used MicDrop to test the hypothesis that growth kinetics of individual gut bacterial taxa are associated with longterm community dynamics in an artificial gut. These demonstrations suggest the MicDrop platform could support future diagnostic efforts to personalize microbiota-directed therapies, as well as to provide comprehensive new insights into the ecology of human gut microbiota.

microbiology↗