Biology subjects

Hathout, Y.

Publications and source records attributed to Hathout, Y..

4 recordsLinked to original sources

bioRxiv2023

Toxoplasma Membrane Inositol Phospholipid Binding Protein TgREMIND Is Essential for Secretory Organelle Function and Host Infection

Apicomplexan parasites have specialized secretory organelles called rhoptries, micronemes, and dense granules that are essential for host infection. Here, we show that TgREMIND, a Toxoplasma gondii protein containing a membrane phospholipid interacting domain, is required for the biogenesis of rhoptries and dense granules. TgREMIND contains a Fes/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain at the N-terminus, known to promote cell membrane bending, and a novel uncharacterized domain that we named REMIND for regulator of membrane interacting domain at the C-terminus. TgREMIND binds to PIP2 lipid species and both F-BAR and REMIND domains are necessary to ensure proper biological activities in vitro and in cellulo. Conditional depletion of TgREMIND results in the absence of dense granules and abnormal transparent rhoptries, leading to a severe inhibition of parasite motility, host invasion, and dissemination. Thus, our study demonstrates that TgREMIND is essential for the proper functioning of key secretory organelles required for successful infection by Toxoplasma.

cell biology↗

bioRxiv2022

Structural analysis of Toxoplasma gondii sortilin

Rhoptries and micronemes are essential for host cell invasion and survival of all apicomplexan parasites, which are composed of numerous obligate intracellular protozoan pathogens including Plasmodium falciparum (malaria) and Toxoplasma gondii (toxoplasmosis) that infect humans and animals causing severe diseases. We identified Toxoplasma gondii TgSORT as an essential cargo receptor, which drives the transport of rhoptry (ROP) and microneme (MIC) proteins to ensure the biogenesis of these secretory organelles. The luminal ectodomain of 752 amino acid long situated at the N-terminus end of TgSORT has been described to bind to MIC and ROP proteins. Here, we present an optimized protocol for expression of the entire luminal ectodomain of TgSORT (Tg-NSORT) in the yeast Pichia pastoris. Optimization of its coding sequence, cloning and transformation of the yeast P. pastoris allowed the secretion of Tg-NSORT. The protein was purified and further analyzed by negative staining electron microscopy. In addition, molecular modeling using AlphaFold identified key differences between human and T gondii sortilin. The structural features that are only present in T. gondii and other apicomplexan parasites were highlighted. Elucidating the roles of these specific structural features may be useful for designing new therapeutic agents against apicomplexan parasites

cell biology↗

bioRxiv2018

High-resolution mass spectrometry-based non-targeted metabolomic discovery of disease and glucocorticoid biomarkers in an animal model of muscular dystrophy

Urine is increasingly being considered as a source of biomarker development in Duchenne Muscular Dystrophy (DMD), a severe, life-limiting disorder that affects approximately 1 in 4500 boys. In this study, we used the mdx mice--a murine model of DMD--to discover biomarkers of disease, as well as pharmacodynamic biomarkers responsive to prednisolone, commonly used to treat DMD. Longitudinal urine samples were analyzed from male age-matched mdx and wild-type mice randomized to prednisolone or vehicle. We used high-resolution mass spectrometry to discover metabolic biomarkers of both disease and glucocorticoid treatment. A large number of metabolites (869 out of 6,334) were found to be significantly different between mdx and wild-type mice at baseline (Bonferroni-adjusted p-value < 0.05), thus being associated with disease status. These included a peak with m/z=357 and creatine, which were also discovered in a previous human study looking at serum. Novel observations included biliverdin and hypusine. These four peaks were also significantly higher in mdx mice compared to wild-type, as well as significantly associated with time after the baseline. Creatine and biliverdin were also associated with treatment after the baseline, but the association with creatine may have been driven by an imbalance at baseline. In conclusion, our study reports a number of biomarkers, both known and novel, which may be related to either the mechanisms of muscle injury in DMD and/or prednisolone treatment.

bioinformatics↗

bioRxiv2018

AMPK Signaling Regulates Expression of Urea Cycle Enzymes in Response to Changes in Dietary Protein Intake

Abundance of urea cycle enzymes in the liver is regulated by the dietary protein intake. Although urea cycle enzyme levels rise in response to a high protein diet, signaling networks that sense dietary protein intake and trigger changes in expression of urea cycle genes have not been identified. The aim of this study was to identify signaling pathway(s) that respond to changes in protein intake and regulate expression of urea cycle genes in mice and human hepatocytes. Mice were adapted to either control or high (HP) protein diets followed by isolation of liver protein and mRNA and integrated analysis of the proteomic and transcriptome profiles. HP diet led to increased expression of mRNA and enzymes in amino acid degradation pathways, and decreased expression of mRNA and enzymes in carbohydrate and fat metabolism, which implicated AMPK as a possible regulator. Primary human hepatocytes, treated with AICAR an activator of AMPK, were used to test whether AMPK regulates expression of urea cycle genes. The abundance of CPS1 and OTC mRNA increased in hepatocytes treated with AICAR, which supports a role for AMPK signaling in regulation of the urea cycle. Because AMPK is either a target of drugs used to treat type-2 diabetes, these drugs might increase the expression of urea cycle enzymes in patients with urea cycle disorders, which could be the basis of a new therapeutic approach.\n\nAuthor summaryIntegrated analysis of transcriptional and proteomic profiles of the liver tissue from mice fed different protein content diets revealed that AMPK signaling pathway regulates expression of urea cycle enzymes.

molecular biology↗