Biology subjects

England, E.

Publications and source records attributed to England, E..

4 recordsLinked to original sources

bioRxiv2024

PfATP2 is an essential flippase on the Plasmodium falciparum surface that influences parasite sensitivity to antiplasmodial compounds

Antimalarials play a crucial role in the fight against malaria. However, resistance of the most virulent malaria parasite, Plasmodium falciparum, to front-line antimalarials is spreading. To identify new antimalarials, millions of compounds have been screened for their ability to inhibit the growth of blood-stage P. falciparum parasites. To gain insight into the mode of action of novel compounds and the ease by which parasites can acquire resistance to them, many have been tested in in vitro evolution experiments, in which parasites are exposed to the compound for a prolonged period of time. In a recent study, parasite resistance to two compounds, MMV007224 and MMV665852, was associated with amplification of the pfatp2 gene, implicating PfATP2, a putative phospholipid flippase, as a parasite drug target or resistance determinant. These two compounds, along with MMV665794 (which is structurally related to MMV007224) had previously been reported to dysregulate pH in parasites. Here, we show that PfATP2 localises to the parasite surface and is essential for parasite growth. We demonstrate that parasites genetically engineered to overexpress PfATP2 display reduced sensitivity to MMV665794, MMV007224 and MMV665852 compared to parasites with a normal expression level of the protein, and that parasites in which PfATP2 is knocked down become hypersensitive to the three compounds. We show that PfATP2 expression level does not affect the cytosolic pH of parasites, or the potency by which MMV665794 or MMV007224 dysregulate parasite pH. We show that PfATP2-overexpressing parasites internalise a fluorescent phosphatidylserine analogue (NBD-PS) at a greater rate than parasites with a normal expression level of PfATP2, and that parasites in which PfATP2 is knocked down have a reduced rate of NBD-PS uptake. Further, we provide evidence that MMV665794 and MMV007224 inhibit both ATP-dependent and ATP-independent NBD-PS internalisation mechanisms, the former at lower concentrations. Together, our data are consistent with PfATP2 serving as a major ATP-dependent phosphatidylserine internalisation mechanism at the parasite plasma membrane, and being a target of MMV665794 and MMV007224.

microbiology↗

bioRxiv2023

Plant pathogenic fungi hijack phosphate starvation signaling with conserved enzymatic effectors

Phosphate availability modulates plant immune function and regulates interactions with beneficial, phosphate-providing, microbes. Here, we describe the hijacking of plant phosphate sensing by a family of Nudix hydrolase effectors from pathogenic Magnaporthe oryzae and Colletotrichum fungi. Structural and enzymatic analyses of the Nudix effector family demonstrate that they selectively hydrolyze inositol pyrophosphates, a molecule used by plants to monitor phosphate status and regulate starvation responses. In M. oryzae, gene deletion and complementation experiments reveal that the enzymatic activity of a Nudix effector significantly contributes to pathogen virulence. Further, we show that this conserved effector family induces phosphate starvation signaling in plants. Our study elucidates a molecular mechanism, utilized by multiple phytopathogenic fungi, that manipulates the highly conserved plant phosphate sensing pathway to exacerbate disease. One-Sentence SummaryA family of conserved enzyme effectors from pathogenic fungi manipulate plant phosphate sensing to promote infection.

plant biology↗

bioRxiv2023

Tozorakimab (MEDI3506): a dual-pharmacology anti-IL-33 antibody that inhibits IL-33 signalling via ST2 and RAGE/EGFR to reduce inflammation and epithelial dysfunction

Interleukin (IL)-33 is a broad-acting alarmin cytokine that can drive inflammatory responses following tissue damage or infection and is a promising target for treatment of inflammatory disease. Here, we describe the identification of tozorakimab (MEDI3506), a potent, human anti-IL-33 monoclonal antibody, which can inhibit reduced IL-33 (IL-33red) and oxidized IL-33 (IL-33ox) activities through distinct serum-stimulated 2 (ST2) and receptor for advanced glycation end products - epidermal growth factor receptor (RAGE-EGFR complex) signalling pathways. We hypothesized that a therapeutic antibody would require an affinity higher than that of ST2 for IL-33, with an association rate greater than 107 M-1 s-1, to effectively neutralize IL-33 following rapid release from damaged tissue. An innovative antibody generation campaign identified tozorakimab, an antibody with a femtomolar affinity for IL-33red and a fast association rate (8.5 x 107 M-1 s-1), which was comparable to soluble ST2. Tozorakimab potently inhibited ST2-dependent inflammatory responses driven by IL-33 in primary human cells and in a murine model of lung epithelial injury. Additionally, tozorakimab prevented the oxidation of IL-33 and its activity via the RAGE/EGFR signalling pathway, thus increasing in vitro epithelial cell migration and repair. Tozorakimab is a novel therapeutic agent with a dual mechanism of action that blocks IL-33red and IL-33ox signalling, offering potential to reduce inflammation and epithelial dysfunction in human disease.

immunology↗

bioRxiv2021

Drosophila functional screening of de novo variants in autism uncovers deleterious variants and facilitates discovery of rare neurodevelopmental diseases

Individuals with autism spectrum disorders (ASD) exhibit an increased burden of de novo variants in a broadening range of genes. We functionally tested the effects of ASD missense variants using Drosophila through humanization rescue and overexpression-based strategies. We studied 79 ASD variants in 74 genes identified in the Simons Simplex Collection and found 38% of them caused functional alterations. Moreover, we identified GLRA2 as the cause of a spectrum of neurodevelopmental phenotypes beyond ASD in eight previously undiagnosed subjects. Functional characterization of variants in ASD candidate genes point to conserved neurobiological mechanisms and facilitates gene discovery for rare neurodevelopmental diseases.

genetics↗