Dataset Information

An NAD⁺-dependent novel transcription factor controls stage conversion in Entamoeba.

ABSTRACT: Developmental switching between life-cycle stages is a common feature among parasitic pathogens to facilitate disease transmission and pathogenesis. The protozoan parasite Entamoeba switches between invasive trophozoites and dormant cysts, but the encystation process remains poorly understood despite being central to amoebic biology. We identify a transcription factor, Encystation Regulatory Motif-Binding Protein (ERM-BP), that regulates encystation. Down-regulation of ERM-BP decreases encystation efficiency resulting in abnormal cysts with defective cyst walls. We demonstrate that direct binding of NAD⁺ to ERM-BP affects ERM-BP conformation and facilitates its binding to promoter DNA. Additionally, cellular NAD⁺ levels increase during encystation and exogenous NAD⁺ enhances encystation consistent with the role of carbon source depletion in triggering Entamoeba encystation. Furthermore, ERM-BP catalyzes conversion of nicotinamide to nicotinic acid, which might have second messenger effects on stage conversion. Our findings link the metabolic cofactors nicotinamide and NAD⁺ to transcriptional regulation via ERM-BP and provide the first mechanistic insights into Entamoeba encystation.

SUBMITTER: Manna D

PROVIDER: S-EPMC6207428 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

An NAD+-dependent novel transcription factor controls stage conversion in Entamoeba.

Manna Dipak D Lentz Christian Stephan CS Ehrenkaufer Gretchen Marie GM Suresh Susmitha S Bhat Amrita A Singh Upinder U

eLife 20181030

Developmental switching between life-cycle stages is a common feature among parasitic pathogens to facilitate disease transmission and pathogenesis. The protozoan parasite Entamoeba switches between invasive trophozoites and dormant cysts, but the encystation process remains poorly understood despite being central to amoebic biology. We identify a transcription factor, Encystation Regulatory Motif-Binding Protein (ERM-BP), that regulates encystation. Down-regulation of ERM-BP decreases en ...[more]

PMID: 30375973

Similar Datasets

Project description:Cancer therapies targeting metabolic derangements unique to cancer cells are emerging as a key strategy to address refractory solid tumors such as pancreatic ductal adenocarcinomas (PDAC) that exhibit resistance to extreme nutrient deprivation in the tumor microenvironment. Nicotinamide adenine dinucleotide (NAD) participates in multiple metabolic pathways and nicotinamide phosphoribosyl transferase (NAMPT) is one of the key intracellular enzymes that facilitate the synthesis of NAD. C-terminal binding proteins 1 and 2 (CtBP) are paralogous NAD-dependent oncogenic transcription factors and dehydrogenases that nucleate an epigenetic complex regulating a cohort of genes responsible for cancer proliferation and metastasis. As adequate intracellular NAD is required for CtBP to oligomerize and execute its oncogenic transcriptional coregulatory activities, we hypothesized that NAD depletion would synergize with CtBP inhibition, improving cell inhibitory efficacy. Indeed, depletion of cellular NAD via the NAMPT inhibitor GMX1778 enhanced growth inhibition induced by either RNAi-mediated CtBP1/2 knockdown or the CtBP dehydrogenase inhibitor 4-chlorophenyl-2-hydroxyimino propanoic acid as much as 10-fold in PDAC cells, while untransformed pancreatic ductal cells were unaffected. The growth inhibitory effects of the NAMPT/CtBP inhibitor combination correlated pharmacodynamically with on-target disruption of CtBP1/2 dimerization, CtBP2 interaction with the CoREST epigenetic regulator, and transcriptional activation of the oncogenic target gene TIAM1. Moreover, this same therapeutic combination strongly attenuated growth of PDAC cell line xenografts in immunodeficient mice, with no observable toxicity. Collectively, our data demonstrate that targeting CtBP in combination with NAD depletion represents a promising therapeutic strategy for PDAC.SignificanceEffective precision therapies are lacking in PDAC. We demonstrate that simultaneous inhibition of NAD metabolism and the oncoprotein CtBP is potently effective at blocking growth of both PDAC cells in culture and human PDAC-derived tumors in mice and should be explored further as a potential therapy for patients with PDAC.

Project description:Entamoeba histolytica is a protozoan parasite and a major cause of dysentery and diarrheal disease in developing countries. Disease transmission from one host to another occurs via cysts which can survive in environmental extremes and are transmitted through contaminated food and water. Recent studies in our lab identified a novel transcription factor, Encystation Regulatory Motif- Binding Protein (ERM-BP), which is responsive to NAD+ and has an important role in encystation. The key residues important for ERM-BP function were demonstrated in vitro using recombinant protein. In this study we demonstrate the in vivo functional consequences of mutations in key domains and their impact on Entamoeba encystation. Our results show that mutations in the DNA binding domain (ERM-BP-DBM) and in the nicotinamidase domain (ERM-BP-C198A) lead to protein mis-localization in both trophozoites and cysts and significantly reduce encystation efficiency. Additionally, we showed that silencing of ERM-BP significantly decreased the size and number of multi-nucleated giant cells (MGC) that form during encystation, indicating that ERM-BP functions upstream of the cellular aggregation that precedes stage conversion. Dissection of epistatic interactions between ERM-BP and a second encystation-related transcription factor, NF-Y revealed that ERM-BP is upstream of NF-Y in controlling the developmental cascade and appears to be one of the earliest regulators of development identified to date in Entamoeba. We also demonstrated that ERM-BP is upregulated during heat stress in Entamoeba, another condition which increases intracellular NAD+ levels and that overexpression of ERM-BP makes E. histolytica and E. invadens parasites more resistant to heat stress. Overexpression of ERM-BP in E. histolytica also induced the formation of cyst-like quadrinucleated cells and formation of MGCs. Overall, our work has identified an important role of ERM-BP in Entamoeba stress response and links an NAD+-responsive transcription factor to both development and heat shock response. Characterization of stress and developmental cascades are important avenues to investigate for Entamoeba, an important human parasitic pathogen.

Dataset Information

An NAD⁺-dependent novel transcription factor controls stage conversion in Entamoeba.

Publications

An NAD<sup>+</sup>-dependent novel transcription factor controls stage conversion in <i>Entamoeba</i>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets