Nitric oxide-dependent changes in Schistosoma mansoni gene expression

Abstract

Keywords Schistosoma mansoni; Nitric oxide (NO); Serial analysis of gene expression (SAGE); Extracellular superoxide dismutase (EC-SOD)Nitric oxide (NO)-related pathways potentially play at least two critical roles in schistosomes, the causative agents of schistosomiasis. First, these pathways may represent essential signaling cascades required for normal parasite physiology and survival. Second, NO-related pathways may also play an important role in parasite-host interactions. Several reports have demonstrated that platyhelminths have nitric oxide synthase (NOS) activity and that NO is likely acting as a signaling molecule in these organisms [1][2][3][4]. Furthermore, the host NO pathway may be involved in host defense against schistosome infection, though its precise role in vivo is not clear [5][6][7].Here we examine changes in parasite gene expression in response to exposure to exogenous NO in vitro. Prior studies have provided evidence of NO-related pathways in adult schistosomes [1,2,8]. However, the physiological role and downstream targets of NO have not been elucidated in adult worms. To assay NO-dependent changes in gene expression, we have used Long-SAGE (serial analysis of gene expression) [9], which provides both the identity of expressed genes and the relative levels of their expression.In Long-SAGE, a short 21 bp sequence tag from the most polyA proximal NlaIII restriction site of an mRNA molecule is used to uniquely identify the source gene from within the genome. Short sequence tags are sampled from all NlaIII-positive transcripts in a mRNA sample and are linked together to form long concatenated molecules that are cloned and sequenced. Quantification of all tags provides a relative measure of gene expression (i.e., mRNA abundance). Using SAGE, we have identified genes which respond to NO by changing expression levels, and we also show by RT-PCR that RNA encoding extracellular superoxide dismutase (EC-SOD, also referred to as signal peptide-SOD [10][11] Publisher's Disclaimer:This article was originally published in a journal published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues that you know, and providing a copy to your institution's administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution's website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: http://www.elsevier.com/ locate/permissionusematerial NIH Public Access After correcting for sequencing error, we sampled 26,072 SAGE tags for the control library and 26,815 tags for the SNP-exposed library. We used log-likelihood statistics (R > 1.5) to reduce the effects of sampling...

Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology

“…In this regard, S . mansoni worms are capable of inducing an adaptive response against redox challenges, by increasing the expression of antioxidant [ 136 , 152 , 153 ], and repair enzymes [ 152 ].…”

Profiling Schistosoma mansoni development using serial analysis of gene expression (SAGE)

“…High-throughput methods exist to identify full transcripts from SAGE tag sequences (Chen et al, 2000(Chen et al, , 2002a and, in some cases, SAGE tag sequences have been used to prime 5′ Rapid Amplification of cDNA Ends (RACE) for isolation of nearly complete transcripts (AGM, unpublished). SAGE has been used to identify nitric oxide responsive changes in gene expression in S. mansoni following a 3 hour exposure to sodium nitroprusside, a nitric oxide donor (Messerli et al, 2006). Nitric oxide is a gaseous intercellular signaling molecule that also plays a role in host-parasite relations.…”

Manipulation of vascular function by blood flukes?

“…It has been suggested that NO-related pathways derived from these sources may play a role in parasite–host interactions, perhaps by permitting the parasites to respond not only to endogenous NO but also to host-derived NO. Indeed it has been demonstrated that exposure of adult schistosomes to an NO donor in vitro does induce rapid changes in gene expression, though these changes are not large-scale 34 . Some NO upregulated genes, such as cyclic nucleotide phosphodiesterase and calcineurin, and some down regulated genes, such as Rac GTPase, share similarity with genes that have previously been reported to be involved in NO signaling in other systems 34 .…”

“…Indeed it has been demonstrated that exposure of adult schistosomes to an NO donor in vitro does induce rapid changes in gene expression, though these changes are not large-scale 34 . Some NO upregulated genes, such as cyclic nucleotide phosphodiesterase and calcineurin, and some down regulated genes, such as Rac GTPase, share similarity with genes that have previously been reported to be involved in NO signaling in other systems 34 . The roles of other NO upregulated genes, (e.g.…”

“…encoding a subunit of vacuolar ATP synthase, a putative coated vesicle membrane protein, and a putative ligand gated ion channel) are entirely unknown. Several other genes, both up and down regulated, encode hypothetical proteins with no homologs outside of the schistosomes 34 .…”