Biology subjects

Berry, L.

Publications and source records attributed to Berry, L..

17 recordsLinked to original sources

bioRxiv2026

ABCE1-dependent translational control links Fe-S cluster biogenesis to parasite growth and lipid homeostasis in Toxoplasma gondii

Toxoplasma gondii relies on tightly regulated protein synthesis to adapt to diverse host environments and to progress through its developmental stages. Here, we investigated the role of the ATP-binding cassette protein ABCE1, a broadly-conserved factor involved in ribosome recycling and translational control. Using a conditional knockdown approach, we demonstrate that depletion of TgABCE1 severely impairs parasite growth and disrupts global protein synthesis, confirming its essential role in maintaining translational capacity. TgABCE1 function depends on the incorporation of iron-sulfur (Fe-S) clusters, likely mediated by the cytosolic iron-sulfur assembly (CIA) pathway component HCF101. Depletion of TgABCE1 phenocopies the defects observed in TgHCF101-depleted parasites, supporting a functional link between these proteins. Notably, loss of TgABCE1 also disrupts lipid homeostasis, resulting in the accumulation of lipid droplets. Together, these findings uncover a critical link between translational regulation, Fe-S cluster biogenesis, and lipid homeostasis, highlighting the central role of proteostasis in parasite survival and development.

microbiology↗

bioRxiv2026

Two anchoring proteins control daughter apical complex assembly in Toxoplasma gondii

During Toxoplasma gondii division, the apical complex--comprising the conoid, apical polar ring (APR), and preconoidal rings--assembles with precise spatiotemporal coordination to form functional daughter buds. Despite their essential roles in invasion, motility, and division, the scaffolding proteins orchestrating this ordered assembly have remained largely unidentified. Here, we identify and characterize RCC1-2 and APR8 as essential factors directing distinct, sequential phases of daughter cell apical complex construction. Both proteins are recruited with precise spatial and temporal dynamics to the daughter buds, where they function as scaffolds rather than static structural components. APR8 transiently occupies the basal region of the APR specifically in early daughter cells. It is dispensable for conoid and PCR initiation, yet its loss causes APR collapse, abolishes SPMT anchoring, and eventually arrests conoid maturation. In contrast, RCC1-2 localizes beneath the APR basal layer and persists throughout daughter cell development, where it contributes to stabilizing the attachment of SPMTs to the APR. Notably, in situ cryo-electron tomography further reveals that the interspersed pillars bridging SPMTs ends to the APR fail to form properly in RCC1-2-depleted parasites. These findings map a hierarchical RCC1-2/APR8-dependent scaffolding process that advances our understanding of parasite replication.

microbiology↗

bioRxiv2026

The Nucleoporin MLP1 of the nuclear basket is essential for nuclear integrity and ploidy maintenance in Trypanosoma brucei

Trypanosoma brucei is a divergent eukaryote parasite responsible for neglected tropical diseases in human and animals, sleeping sickness or human African trypanosomiasis and nagana respectively. Besides scientific interest, understanding the specific features of its biology has medical and economical relevance. Nuclear pore complexes (NPCs) are large multiprotein channels embedded in the nuclear envelope that regulate nucleo-cytoplasmic transport. Beyond this role, NPCs also participate in essential nuclear processes such as chromosome segregation, transcription, and cytokinesis. Here, we showed that Myosin-like protein-1 (MLP1) localized to the nuclear basket of NPCs in T. brucei. Silencing of TbMLP1 by RNA interference in T. brucei procyclic cells caused marked defects in parasite growth, severe impairment of messenger RNA export, disorganization of nuclear structure, and pronounced genomic instability. Flow cytometry and FISH analyses revealed abnormal DNA content and a sharp reduction in disomic cells, accompanied by increased numbers of monosomic, trisomic, and polysomic cells, indicating an untolerated aneuploidy. These findings reveal that TbMLP1 links NPC function to multiple key cellular pathways. We provide new insights into the mechanisms that preserve nuclear architecture, nuclear envelope morphology, genome stability, and faithful chromosome segregation, including effects on kinetochore distribution and organization of the mitotic spindle. Author SummaryTrypanosoma brucei is the microscopic parasite responsible for sleeping sickness in humans and nagana in cattle; learning more about its basic biology may help identify weak points that could one day be targeted in new treatments. In this work, we studied a protein called MLP1, which sits at the nuclear pores--the gateways that control what enters and leaves the nucleus. Our findings revealed that MLP1 is essential for ensuring proper movement of messenger RNA, keeping the nucleus stable, and allowing chromosomes to be shared equally when cells divided. In total, we gained new insight into the basic biology of a parasite that remains a major health concern in many regions of the world, showing how a single structural protein can influence many vital processes within it.

microbiology↗

bioRxiv2025

An acyclic nucleoside phosphonate effectively blocks the egress of the malaria parasite by inhibiting the synthesis of cyclic GMP.

The urgent need for new antimalarial therapies arises from the alarming spread of malaria parasite resistance to existing drugs. A promising candidate, UA2239, an acyclic nucleoside phosphonate with a guanine as nucleobase, demonstrates rapid and irreversible cytotoxic effects on Plasmodium parasites, both in vitro and in an animal model. It blocks the active exit process, named egress, of merozoites and gametes from infected erythrocytes. UA2239 disrupts the essential cGMP-dependent egress pathway by decreasing cGMP levels in the parasite, making guanylate cyclase (PfGC) the most likely target. We also uncovered the remarkable molecular mechanism of resistance developed by parasites after prolonged exposure to the drug, which involves mutating not the target itself, but a downstream effector. The unique mechanism action of UA2239 makes it a valuable first-in-class candidate for further development and its ability to inhibit both parasite growth and transmission highlights its therapeutic potential as a dual-stage antimalarial agent.

microbiology↗

bioRxiv2024

TgGloL is an atypical glyoxalase/VOC domain-containing apicoplast protein that is important for the growth of Toxoplasma

Glycolysis is a conserved metabolic pathway that converts glucose into pyruvate in the cytosol, producing ATP and NADH. In Toxoplasma gondii and several other apicomplexan parasites, some glycolytic enzymes have isoforms located in their plastid (called the apicoplast). In this organelle, glycolytic intermediates like glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) are imported from the cytosol and further metabolized, providing ATP, reducing power, and precursors for anabolic pathways such as isoprenoid synthesis. However, GAP and DHAP can spontaneously convert into methylglyoxal, a toxic by-product detoxified by the glyoxalase system, typically involving Glyoxalase-1 (Glo-1) and Glyoxalase-2 (Glo-2). In T. gondii, we identified an atypical protein, TgGloL, containing a Glo-1-like motif but with limited homology to typical Glo enzymes. TgGloL localizes to the apicoplast, and its conditional knockdown impairs parasite growth, indicating its importance. While a specific and direct role for TgGloL in methylglyoxal detoxification within the apicoplast remains unclear, it is crucial for maintaining organelle homeostasis and for overall parasite fitness.

microbiology↗

bioRxiv2024

The malaria parasite PP1 phosphatase controls the initiation of the egress pathway of asexual blood-stages by regulating the rounding-up of the vacuole

A sustained blood-stage infection of the human malaria parasite P. falciparum relies on the active exit of merozoites from their host erythrocytes. During this process, named egress, the infected red blood cell undergoes sequential morphological events: the rounding-up of the surrounding parasitophorous vacuole, the disruption of the vacuole membrane and finally the rupture of the red blood cell membrane. These events are coordinated by two intracellular second messengers, cGMP and calcium ions (Ca2+), that control the activation of their dedicated kinases, PKG and CDPKs respectively, and thus the secretion of parasitic factors that assist membranes rupture. We had previously identified the serine-threonine phosphatase PP1 as an essential enzyme required for the rupture of the surrounding vacuole. Here, we address its precise positioning and function within the egress signaling pathway by combining chemical genetics and live-microscopy. Fluorescent reporters of the parasitophorous vacuole morphology were expressed in the conditional PfPP1-iKO line which allowed to monitor the kinetics of natural and induced egress, as well as the rescue capacity of known egress inducers. Our results underscore a dual function for PP1 in the egress cascade. First, we provide further evidence that PP1 controls the homeostasis of the second messenger cGMP by modulating the basal activity of guanylyl cyclase alpha and consequently the PKG-dependent downstream Ca2+ signaling. Second, we demonstrate that PP1 also regulates the rounding-up of the parasitophorous vacuole, as this step is almost completely abolished in PfPP1-null schizonts. Strikingly, our data show that rounding-up is the step triggered by egress inducers, and support its reliance on Ca2+, as the calcium ionophore A23187 bypasses the egress defect of PfPP1-null schizonts, restores proper egress kinetics and promotes the initiation of the rounding-up step. Therefore, this study places the phosphatase PP1 upstream of the cGMP-PKG signaling pathway, and sheds new light on the regulation of rounding-up, the first step in P. falciparum blood stage egress cascade. AUTHOR SUMMARYMalaria caused by Plasmodium falciparum infections remains a major human threat in endemic countries. Its proliferation within the host relies on the iteration of red blood cell invasion, multiplication and release of newly formed parasites in the blood circulation. This last step, named egress, is tightly regulated by a signaling pathway controlled by phospho-regulation. The phosphatase PP1 is a conserved pleiotropic enzyme that regulates various biological processes in mammals and controls the replication and egress mechanisms in P. falciparum. Indeed, PP1-depleted parasites are unable to egress from the erythrocytes and remain trapped within a vacuole in the host cell. Here, using fluorescent reporters of the surrounding vacuole, and pharmacological inducers of the egress pathway, we analyzed natural and induced egress by time-lapse video-microscopy. Our results underscore a dual function of PP1 during egress and identify the phosphatase as an early regulator of this essential process.

microbiology↗

bioRxiv2024

Intracellular Pseudomonas aeruginosa persist and evade antibiotic treatment in a wound infection model

Persistent bacterial infections evade host immunity and resist antibiotic treatments through various mechanisms that are difficult to evaluate in a living host. Pseudomonas aeruginosa is a main cause of chronic infections in patients with cystic fibrosis (CF) and wounds. Here, by immersing wounded zebrafish embryos in a suspension of P. aeruginosa isolates from CF patients, we established a model of persistent infection that mimics a murine chronic skin infection model. Live and electron microscopy revealed persisting aggregated P. aeruginosa inside zebrafish cells, including macrophages, at unprecedented resolution. Persistent P. aeruginosa exhibited adaptive resistance to several antibiotics, host cell permeable drugs being the most efficient. Moreover, persistent bacteria could be partly re-sensitized to antibiotics upon addition of anti-biofilm molecules that dispersed the bacterial aggregates in vivo. Collectively, this study demonstrates that an intracellular location protects P. aeruginosa in vivo from host innate immunity and antibiotics, and provides new insights into efficient treatments against chronic infections.

microbiology↗

bioRxiv2024

HCF101 is a novel component of the CIA cytosolic iron-sulfur synthesis pathway in the human pathogen Toxoplasma gondii

Several key cellular functions depend on proteins harboring an iron-sulfur (Fe-S) cofactor. As these Fe-S proteins localize to several subcellular compartments, they require a dedicated machinery for cofactor assembly. For instance, in plants and algae there are Fe-S cluster synthesis pathways localizing to the cytosol, but also present in the mitochondrion and in the chloroplast, two organelles of endosymbiotic origin. Toxoplasma gondii is a plastid-bearing parasitic protist responsible for a pathology affecting humans and other warm-blooded vertebrates. We have characterized the Toxoplasma homologue of HCF101, originally identified in plants as a protein transferring Fe-S clusters to photosystem I subunits in the chloroplast. Contrarily to plants, we have shown that HCF101 does not localize to the plastid in parasites, but instead is an important component of the cytosolic Fe-S assembly (CIA) pathway which is vital for Toxoplasma. While the CIA pathway is widely conserved in eukaryotes, it is the first time the involvement of HCF101 in this pan-eukaryotic machinery is established. Moreover, as this protein is essential for parasite viability and absent from its mammalian hosts, it constitutes a novel and promising potential drug target.

microbiology↗

bioRxiv2023

Iron depletion has different consequences on the growth and survival of Toxoplasma gondii strains

Toxoplasma gondii is an obligate intracellular parasite that is responsible for a pathology called toxoplasmosis which is primarily affecting immunocompromised individuals and developing fetuses. The parasite is able to scavenge essential nutrients from its host to support its own growth and survival. Among them, iron is one of the most important elements needed to sustain basic cellular functions, as it is involved in a number of key metabolic processes, including oxygen transport, redox balance and electron transport. We have evaluated the effects of an iron chelator on the development of several parasite strains and found that they differed in their ability to tolerate iron depletion. The growth of parasites usually associated with a model of acute toxoplasmosis was strongly impacted by iron depletion, while cystogenic strains were less sensitive as they were able to convert into persisting developmental forms which are associated with the chronic form of the disease. Ultrastructural and biochemical characterization of the impact of iron depletion on the parasites also highlighted striking changes in both in their metabolism and the one of the host, with a marked accumulation of lipid droplets and perturbation of lipid homeostasis. Overall, our study demonstrates that although acute iron depletion has an important effect on the growth of T. gondii, it has a more profound impact on actively dividing parasites, while less metabolically-active parasite forms may be able to avoid some of the most detrimental consequences.

microbiology↗

bioRxiv2022

Disruption of the plastid-hosted iron-sulfur cluster biogenesis pathway in Toxoplasma gondii has pleiotropic effects irreversibly impacting parasite viability

Like many other apicomplexan parasites, Toxoplasma gondii contains a plastid harbouring key metabolic pathways, including the SUF pathway that is involved in the biosynthesis of iron-sulfur clusters. These cofactors are key for a variety of proteins involved in important metabolic reactions, potentially including plastidic pathways for the synthesis of isoprenoid and fatty acids. It was shown previously that impairing the NFS2 cysteine desulfurase, involved in the first step of the SUF pathway, leads to an irreversible killing of intracellular parasites. However, the metabolic impact of disrupting the pathway remained unexplored. We have generated another mutant of the pathway, deficient for the SUFC ATPase, and we have investigated in details the phenotypic consequences of TgNFS2 and TgSUFC depletion on parasite homeostasis. Our analysis confirms that Toxoplasma SUF mutants are severely and irreversibly impacted in growth: cell division and membrane homeostasis are particularly affected. Lipidomic analysis suggests a defect in apicoplast-generated fatty acids, along with a simultaneous increase in scavenging of host-derived lipids. However, addition of exogenous lipids did not allow full restauration of growth, suggesting other more important cellular functions were impacted in addition to fatty acid synthesis. For instance, we have shown that the SUF pathway is also key for generating isoprenoid-derived precursors necessary for the proper targeting of GPI-anchored proteins as well as for the parasite gliding motility. Thus, plastid-generated iron-sulfur clusters support the functions of proteins involved in several vital downstream cellular pathways, which implies the SUF machinery may be explored for discovering new potential anti-Toxoplasma targets.

microbiology↗

bioRxiv2022

Cystic fibrosis patient-derived bronchial organoids unveil druggable pathways against Mycobacterium abscessus infection.

Mycobacterium abscessus (Mabs) drives life-shortening mortality in cystic fibrosis (CF) patients, primarily because of its resistance to chemotherapeutic agents. To date, our knowledge on the host and bacterial determinants driving Mabs pathology in CF patient lung remains rudimentary. Here, we used human airway organoids (AOs) microinjected with smooth (S) or rough (R-)Mabs to evaluate bacteria fitness, host responses to infection, and new treatment efficacy. We show that S Mabs formed biofilm, R Mabs formed cord serpentines and displayed a higher virulence. While Mabs infection triggers enhanced oxidative stress, pharmacological activation of antioxidant pathways resulted in better control of Mabs growth. Genetic and pharmacological inhibition of the CFTR is associated with better growth and higher virulence of S and R Mabs. Finally, pharmacological activation of antioxidant pathways inhibited Mabs growth and improved efficacy in combination with cefoxitin, a first line antibiotic. In conclusion, we have established AOs as a suitable human system to decipher mechanisms of CF-driven respiratory infection by Mabs and propose antioxidants as a potential host-directed strategy to improve Mabs infection control.

cell biology↗

bioRxiv2021

The genome of stress tolerant crop wild relativePaspalum vaginatum leads to increased biomassproductivity in the crop Zea mays

A number of crop wild relatives can tolerate extreme stressed to a degree outside the range observed in their domesticated relatives. However, it is unclear whether or how the molecular mechanisms employed by these species can be translated to domesticated crops. Paspalum Paspalum vaginatum is a self-incompatible and multiply stress-tolerant wild relative of maize and sorghum. Here we describe the sequencing and pseudomolecule level assembly of a vegetatively propagated accession of P. vaginatum. Phylogenetic analysis based on 6,151 single-copy syntenic orthologous conserved in 6 related grass species placed paspalum as an outgroup of the maize-sorghum clade demonstrating paspalum as their closest sequenced wild relative. In parallel metabolic experiments, paspalum, but neither maize nor sorghum, exhibited significant increases in trehalose when grown under nutrient-deficit conditions. Inducing trehalose accumulation in maize, imitating the metabolic phenotype of paspalum, resulting in autophagy dependent increases in biomass accumulation.

plant biology↗

bioRxiv2021

Pharmacological activation of PIEZO1 in human red blood cells prevents Plasmodium falciparum invasion

An inherited gain-of-function variant (E756 del) in the mechanosensitive cationic channel PIEZO1 was recently shown to confer a significant protection against severe malaria. Here, we demonstrate in vitro that human red blood cell (RBC) infection by Plasmodium falciparum is prevented by the pharmacological activation of PIEZO1. The PIEZO1 activator Yoda1 inhibits RBC invasion, without affecting parasite intraerythrocytic growth, division or egress. RBC dehydration, echinocytosis and intracellular Na+/K+ imbalance are unrelated to the mechanism of protection. Inhibition of invasion is maintained, even after a prolonged wash out of Yoda1. Similarly, the chemically unrelated activators Jedi1 and Jedi2 potently inhibit parasitemia, further indicating a PIEZO1-dependent mechanism. Notably, Yoda1 treatment significantly reduced RBC surface receptors of P. falciparum, and decreased merozoite attachment and subsequent RBC deformation. Altogether these data indicate that the pharmacological activation of Piezo1 in human RBCs inhibits malaria infection by impairing P. falciparum invasion.

microbiology↗

bioRxiv2020

Co-option of Plasmodium falciparum PP1 for egress from host erythrocytes

Asexual proliferation of the Plasmodium parasites that cause malaria follow a developmental program that alternates non-canonical intraerythrocytic replication with dissemination to new host cells. We carried out a functional analysis of the Plasmodium falciparum homolog of Protein Phosphatase 1 (PfPP1), a universally conserved cell cycle factor in eukaryotes, to investigate regulation of parasite proliferation. PfPP1 is indeed required for efficient replication, but is absolutely essential for egress of parasites from host red blood cells. A phosphoproteomic screen and chemical-genetic analysis provided evidence for a HECT E3 protein-ubiquitin ligase, as well as a fusion protein with guanylyl cyclase and phospholipid transporter domains, as functional targets of PfPP1. Extracellular phosphatidylcholine stimulates PfPP1-dependent egress. Parasite PfPP1 acts as a master regulator that can integrate multiple cell-intrinsic pathways with external signals to direct parasite egress from host cells.

microbiology↗

bioRxiv2019

Division and adaptation to host nutritional environment of apicomplexan parasites depend on apicoplast lipid metabolic plasticity and host organelles remodelling

Apicomplexan parasites are unicellular eukaryotes responsible for major human diseases including malaria and toxoplasmosis. Apicomplexan parasites must obtain and combine lipids both from host cell scavenging and de novo synthesis to maintain parasite propagation and survival within their human host. Major questions on the actual role for each lipid source or how these are regulated upon fluctuating host nutritional conditions remain unanswered. Characterization of an apicoplast acyltransferase TgATS2, shows that the apicoplast provides local (lyso)phosphatidic acid balance, which is required for the recruitment of a novel dynamin (TgDrpC) critical during parasite cytokinesis. Disruption of TgATS2 led parasites to shift metabolic lipid acquisition from de novo synthesis towards host scavenging. Importantly, both lipid scavenging and de novo synthesis pathways exhibit major metabolic and cellular plasticity upon sensing host lipid-deprived environments through concomitant (i) up-regulation of de novo fatty acid synthesis capacities in the apicoplast, and (ii) parasite-driven host cell remodelling to generate multi-membrane-bound structures from host organelles that are imported towards the parasite.

microbiology↗

bioRxiv2018

Killing from the inside: Intracellular role of T3SS in the fate of Pseudomonas aeruginosa within macrophages revealed by mgtC and oprF mutants

While considered solely an extracellular pathogen, increasing evidence indicates that Pseudomonas aeruginosa encounters intracellular environment in diverse mammalian cell types, including macrophages. In the present study, we have deciphered the intramacrophage fate of wild-type P. aeruginosa PAO1 strain by live and electron microscopy. P. aeruginosa first resided in phagosomal vacuoles and subsequently could be detected in the cytoplasm, indicating phagosomal escape of the pathogen, a finding also supported by vacuolar rupture assay. The intracellular bacteria could eventually induce cell lysis. Two bacterial factors, MgtC and OprF, recently identified to be important for survival of P. aeruginosa in macrophages, were found to be involved in bacterial escape from the phagosome as well as cell lysis caused by intracellular bacteria. Strikingly, type III secretion system (T3SS) genes of P. aeruginosa were down-regulated within macrophages in both mgtC and oprF mutants. Concordantly, cyclic di-GMP (c-di-GMP) level was increased in both mutants, providing a clue for negative regulation of T3SS inside macrophages. Consistent with the phenotypes and gene expression pattern of mgtC and oprF mutants, a T3SS mutant ({Delta}pscN) exhibited defect in phagosomal escape and macrophage lysis driven by internalized bacteria. Importantly, these effects appeared to be largely dependent on the ExoS effector, in contrast with the known T3SS-dependent, but ExoS independent, cytotoxicity caused by extracellular P. aeruginosa towards macrophages. Hence, our work highlights T3SS and ExoS, whose expression is modulated by MgtC and OprF, as key players in the intramacrophage life of P. aeruginosa, allowing internalized bacteria to evade macrophages.\n\nAuthor summaryThe ability of professional phagocytes to ingest and kill microorganisms is central to host defense and Pseudomonas aeruginosa has developed mechanisms to avoid being killed by phagocytes. While considered an extracellular pathogen, P. aeruginosa has been reported to be engulfed by macrophages in animal models. Here, we visualized the fate of P. aeruginosa within cultured macrophages, revealing macrophage lysis driven by intracellular P. aeruginosa. Two bacterial factors, MgtC and OprF, recently discovered to be involved in the intramacrophage survival of P. aeruginosa, appeared to play role in this cytotoxicity caused by intracellular bacteria. We provided evidence that type III secretion system (T3SS) gene expression is lowered intracellularly in mgtC and oprF mutants. We further showed that intramacrophage P. aeruginosa uses its T3SS, specifically the ExoS effector, to promote phagosomal escape and cell lysis. We thus describe a transient intramacrophage stage of P. aeruginosa that could contribute to bacterial dissemination.

microbiology↗

bioRxiv2017

Common Piezo1 allele in African populations causes xerocytosis and attenuates Plasmodium infection

Hereditary xerocytosis (HX) is thought to be a rare genetic condition characterized by red blood cell (RBC) dehydration with mild hemolysis. Gain-of-function (GOF) mutations in mechanosensitive Piezo1 ion channels are identified in HX patients. RBC dehydration is linked to reduced Plasmodium infection rates in vitro. We engineered a Piezo1 mouse model of HX and show that Plasmodium infection fails to cause experimental cerebral malaria in these mice. Furthermore, we identified a novel GOF human Piezo1 variant, E756del, present in a third of African population. Remarkably, RBCs from individuals carrying this allele are dehydrated and protected against Plasmodium infection in vitro. The presence of an HX-causing Piezo1 mutation at such high frequencies in African population is surprising, and suggests an association with malaria resistance.

physiology↗