Biology subjects

Suleiman, R. L.

Publications and source records attributed to Suleiman, R. L..

3 recordsLinked to original sources

bioRxiv2026

CRISPR/Cas9 knockout and editing of the major cysteine protease in Entamoeba histolytica

Entamoeba histolytica is the cause of amoebiasis, a diarrheal infection that is a significant source of morbidity and mortality. Despite its importance to human health, the basic mechanism of disease is poorly understood. E. histolytica is dramatically understudied, even in comparison to other understudied parasites, due to challenging features of its genome and the relative paucity of genetic tools. A major limitation is the historical lack of gene knockouts or manipulation of the endogenous genome. While CRISPR/Cas9 has led to major advances in the tractability of numerous parasites, until recently, it was not applied in E. histolytica, except for the demonstration of editing of an episomal plasmid. In this study, we further developed CRISPR/Cas9 and demonstrated the successful targeting of the endogenous cysteine protease 5 (CP5) gene, a major virulence factor. Further, we demonstrated successful CRISPR/Cas9-based editing of this locus, which represents the very first successful editing of the endogenous genome. In the course of these approaches, we developed the viral skip peptide approach as well as a suite of endogenous promoters to drive tunable levels of gene expression. We also performed the most extensive empirical testing of nuclear localization signals in E. histolytica that has been done. Thus, this work demonstrates effective CRISPR/Cas9-based manipulation of the endogenous genome, together with significant advances to the overall genetic toolkit that extend beyond CRISPR/Cas9. These great improvements in the tractability of E. histolytica thus set the stage for future studies to better define its virulence.

microbiology↗

bioRxiv2026

Human cell F-actin density differentially influences trogocytosis and phagocytosis by Entamoeba histolytica

Entamoeba histolytica is a parasitic amoeba and the cause amoebiasis, a common but understudied human diarrheal disease. E. histolytica trophozoites ("amoebae") kill human cells through a process of cell-nibbling called trogocytosis (trogo-: nibble) that contributes to tissue damage. Amoebae can also perform phagocytosis, in which entire human cells are ingested. Based on studies in which human cells were artificially stiffened, it was suggested that amoebae perform phagocytosis on stiffer cells, and trogocytosis on less stiff cells. A handful of recent studies of macrophages that used artificial targets or artificially stiffened target cells also suggested a similar relationship between target stiffness and trogocytosis/phagocytosis efficiencies. To better evaluate the impact of target cell stiffness on amoebic ingestion, instead of using artificial targets or artificial cell stiffening, we created human cell mutants in which individual Rho-pathway genes were knocked down. Strikingly, amoebae performed quantitatively reduced levels of trogocytosis on all knockdown mutants, regardless of cytoskeletal F-actin organization. In contrast, amoebic phagocytosis efficiency was inversely correlated with human cell cortical F-actin density. Thus, human cell F-actin organization differentially influences amoebic trogocytosis and phagocytosis. This is more complex than the conclusions of studies that used artificial targets or artificially stiffened cells. Our results emphasize that the dynamic nature of the cytoskeleton in living cells impacts trogocytosis. In addition to shedding light on the burgeoning field of eukaryotic trogocytosis, this work extends knowledge of amoebic ingestion processes that contribute to disease.

microbiology↗

bioRxiv2018

Trogocytosis by Entamoeba histolytica mediates acquisition and display of human cell membrane proteins and evasion of lysis by human serum

Entamoeba histolytica is the protozoan parasite responsible for amoebiasis. We previously showed that E. histolytica kills human cells through a mechanism that we termed trogocytosis (trogo-: nibble), due to its resemblance to trogocytosis in other organisms. In parasites, trogocytosis is used to kill host cells. In multicellular organisms, trogocytosis is used for cell-cell interactions in the immune system, in the central nervous system, and during development. Thus, nibbling is an emerging theme in cell-cell interactions both within and between species, and it is relevant to host-pathogen interactions in many different contexts. When trogocytosis occurs between mammalian immune cells, cell membrane proteins from the nibbled cell can be acquired and displayed by the recipient cell. In this study, we tested the hypothesis that through trogocytosis of human cells, amoebae acquire and display human cell membrane proteins. Here we demonstrate for the first time that through trogocytosis, E. histolytica acquires and displays human cell membrane proteins and that this leads to protection from lysis by human serum. Protection from human serum only occurs after amoebae have undergone trogocytosis of live cells, but not phagocytosis of dead cells. Likewise, mutant amoebae that exhibit a phagocytosis defect, but are unaltered in their capacity to perform trogocytosis, are nevertheless protected from human serum. Our studies are the first to demonstrate that amoebae can display human cell membrane proteins and suggest that acquisition and display of membrane proteins is a general feature of trogocytosis that is not restricted to trogocytosis between mammalian immune cells. These studies have major implications for interactions between E. histolytica and the immune system and also reveal a novel strategy for immune evasion by a pathogen. Since other microbial eukaryotes use trogocytosis for cell killing, our findings may apply to the pathogenesis of other infections.\n\nAuthor SummaryEntamoeba histolytica is an intestinal parasite that causes amoebiasis, a potentially fatal diarrheal disease. Abscesses in organs outside of the intestine, such as the liver, can occur when amoebae are able to breach the intestinal wall and travel through the blood stream to other areas of the body. We previously showed that E. histolytica kills human cells by taking \"bites\" of human cell material in a process that we named trogocytosis (trogo-: nibble). Mammalian immune cells use trogocytosis to acquire proteins from other cells which impacts cell-cell communication. Here we tested the hypothesis that trogocytosis allows E. histolytica to acquire and display proteins from human cells allowing amoebae to survive in the blood stream. We demonstrate for the first time that through trogocytosis, E. histolytica acquires and displays human cell membrane proteins. We also demonstrate that trogocytosis of human cells allows amoebae to survive in human serum. These studies reveal a novel strategy for immune evasion by a pathogen and may apply to the pathogenesis of other infections.

microbiology↗