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1.  Long non-coding RNA INXS is a critical mediator of BCL-XS induced apoptosis 
Nucleic Acids Research  2014;42(13):8343-8355.
BCL-X mRNA alternative splicing generates pro-apoptotic BCL-XS or anti-apoptotic BCL-XL gene products and the mechanism that regulates splice shifting is incompletely understood. We identified and characterized a long non-coding RNA (lncRNA) named INXS, transcribed from the opposite genomic strand of BCL-X, that was 5- to 9-fold less abundant in tumor cell lines from kidney, liver, breast and prostate and in kidney tumor tissues compared with non-tumors. INXS is an unspliced 1903 nt-long RNA, is transcribed by RNA polymerase II, 5′-capped, nuclear enriched and binds Sam68 splicing-modulator. Three apoptosis-inducing agents increased INXS lncRNA endogenous expression in the 786-O kidney tumor cell line, increased BCL-XS/BCL-XL mRNA ratio and activated caspases 3, 7 and 9. These effects were abrogated in the presence of INXS knockdown. Similarly, ectopic INXS overexpression caused a shift in splicing toward BCL-XS and activation of caspases, thus leading to apoptosis. BCL-XS protein accumulation was detected upon INXS overexpression. In a mouse xenograft model, intra-tumor injections of an INXS-expressing plasmid caused a marked reduction in tumor weight, and an increase in BCL-XS isoform, as determined in the excised tumors. We revealed an endogenous lncRNA that induces apoptosis, suggesting that INXS is a possible target to be explored in cancer therapies.
PMCID: PMC4117780  PMID: 24992962
2.  Imatinib Treatment Causes Substantial Transcriptional Changes in Adult Schistosoma mansoni In Vitro Exhibiting Pleiotropic Effects 
Schistosome parasites cause schistosomiasis, one of the most important infectious diseases worldwide. For decades Praziquantel (PZQ) is the only drug widely used for controlling schistosomiasis. The absence of a vaccine and fear of PZQ resistance have motivated the search for alternatives. Studies on protein kinases (PKs) demonstrated their importance for diverse physiological processes in schistosomes. Among others two Abl tyrosine kinases, SmAbl1 and SmAbl2, were identified in Schistosoma mansoni and shown to be transcribed in the gonads and the gastrodermis. SmAbl1 activity was blocked by Imatinib, a known Abl-TK inhibitor used in human cancer therapy (Gleevec/Glivec). Imatinib exhibited dramatic effects on the morphology and physiology of adult schistosomes in vitro causing the death of the parasites.
Methodology/Principal Findings
Here we show modeling data supporting the targeting of SmAbl1/2 by Imatinib. A biochemical assay confirmed that SmAbl2 activity is also inhibited by Imatinib. Microarray analyses and qRT-PCR experiments were done to unravel transcriptional processes influenced by Imatinib in adult schistosomes in vitro demonstrating a wide influence on worm physiology. Surface-, muscle-, gut and gonad-associated processes were affected as evidenced by the differential transcription of e.g. the gynecophoral canal protein gene GCP, paramyosin, titin, hemoglobinase, and cathepsins. Furthermore, transcript levels of VAL-7 and egg formation-associated genes such as tyrosinase 1, p14, and fs800-like were affected as well as those of signaling genes including a ribosomal protein S6 kinase and a glutamate receptor. Finally, a comparative in silico analysis of the obtained microarray data sets and previous data analyzing the effect of a TGFβR1 inhibitor on transcription provided first evidence for an association of TGFβ and Abl kinase signaling. Among others GCP and egg formation-associated genes were identified as common targets.
The data affirm broad negative effects of Imatinib on worm physiology substantiating the role of PKs as interesting targets.
Author Summary
Schistosomiasis is an infectious disease caused by schistosome parasites, affecting millions of people worldwide. The pathogenic consequences of schistosomiasis are caused by the eggs inducing severe organ inflammations. Praziquantel is widely used to treat schistosomiasis; however, there is fear of resistance developing. Research in the last decades has provided strong evidence for the importance of protein kinases controlling physiological processes in schistosomes. Two Abl-kinases were discovered, whose activities are blocked by Imatinib, an inhibitor known as Gleevec/Glivec from human cancer therapy. In vitro, Imatinib treatment led to dramatic effects on morphology and physiology and to the death of adult schistosomes. Besides modeling of the schistosome Abl-kinases we investigated the effect of Imatinib on gene expression in adult S. mansoni by performing transcriptomics and discovered a wide influence on the transcription of genes involved in surface-, muscle-, gut- and gonad-associated processes. Comparative in silico analyses with data from a previous study indicated a yet unknown association of TGFβ and Abl-kinase signaling in schistosomes. Among others the gynecophoral canal protein gene GCP was identified as a common target. The data obtained demonstrate a substantial influence of Imatinib on physiological processes in adult schistosomes supporting the role of protein kinases as interesting targets.
PMCID: PMC4055459  PMID: 24921634
3.  Expression analysis and in silico characterization of intronic long noncoding RNAs in renal cell carcinoma: emerging functional associations 
Molecular Cancer  2013;12:140.
Intronic and intergenic long noncoding RNAs (lncRNAs) are emerging gene expression regulators. The molecular pathogenesis of renal cell carcinoma (RCC) is still poorly understood, and in particular, limited studies are available for intronic lncRNAs expressed in RCC.
Microarray experiments were performed with custom-designed arrays enriched with probes for lncRNAs mapping to intronic genomic regions. Samples from 18 primary RCC tumors and 11 nontumor adjacent matched tissues were analyzed. Meta-analyses were performed with microarray expression data from three additional human tissues (normal liver, prostate tumor and kidney nontumor samples), and with large-scale public data for epigenetic regulatory marks and for evolutionarily conserved sequences.
A signature of 29 intronic lncRNAs differentially expressed between RCC and nontumor samples was obtained (false discovery rate (FDR) <5%). A signature of 26 intronic lncRNAs significantly correlated with the RCC five-year patient survival outcome was identified (FDR <5%, p-value ≤0.01). We identified 4303 intronic antisense lncRNAs expressed in RCC, of which 22% were significantly (p <0.05) cis correlated with the expression of the mRNA in the same locus across RCC and three other human tissues. Gene Ontology (GO) analysis of those loci pointed to 'regulation of biological processes’ as the main enriched category. A module map analysis of the protein-coding genes significantly (p <0.05) trans correlated with the 20% most abundant lncRNAs, identified 51 enriched GO terms (p <0.05). We determined that 60% of the expressed lncRNAs are evolutionarily conserved. At the genomic loci containing the intronic RCC-expressed lncRNAs, a strong association (p <0.001) was found between their transcription start sites and genomic marks such as CpG islands, RNA Pol II binding and histones methylation and acetylation.
Intronic antisense lncRNAs are widely expressed in RCC tumors. Some of them are significantly altered in RCC in comparison with nontumor samples. The majority of these lncRNAs is evolutionarily conserved and possibly modulated by epigenetic modifications. Our data suggest that these RCC lncRNAs may contribute to the complex network of regulatory RNAs playing a role in renal cell malignant transformation.
PMCID: PMC3834536  PMID: 24238219
Renal cell carcinoma (RCC); Unspliced intronic long noncoding RNAs; Antisense lncRNAs; Microarray analysis; Molecular markers; Gene expression correlation; Histone methylation; Histone acetylation; Evolutionary lncRNA conservation
4.  Combinatory Microarray and SuperSAGE Analyses Identify Pairing-Dependently Transcribed Genes in Schistosoma mansoni Males, Including Follistatin 
Schistosomiasis is a disease of world-wide importance and is caused by parasitic flatworms of the genus Schistosoma. These parasites exhibit a unique reproduction biology as the female's sexual maturation depends on a constant pairing-contact to the male. Pairing leads to gonad differentiation in the female, and even gene expression of some gonad-associated genes is controlled by pairing. In contrast, no morphological changes have been observed in males, although first data indicated an effect of pairing also on gene transcription in males.
Methodology/Principal Findings
To investigate the influence of pairing on males, we performed a combinatory approach applying SuperSAGE and microarray hybridization, generating the most comprehensive data-set on differential transcription available to date. Of 6,326 sense transcripts detected by both analyses, 29 were significantly differentially transcribed. Besides mutual confirmation, the two methods complemented each other as shown by data comparison and real-time PCR, which revealed a number of genes with consistent regulation across all methods. One of the candidate genes, follistatin of S. mansoni (SmFst) was characterized in more detail by in situ hybridization and yeast two-hybrid (Y2H) interaction analyses with potential binding partners.
Beyond confirming previously hypothesized differences in metabolic processes between pairing-experienced (EM) and pairing-unexperienced males (UM), our data indicate that neuronal processes are involved in male-female interaction but also TGFβ-signaling. One candidate revealing significant down-regulation in EM was the TGFβ-pathway controlling molecule follistatin (SmFst). First functional analyses demonstrated SmFst interaction with the S. mansoni TGFβ-receptor agonists inhibin/activin (SmInAct) and bone morphogenic protein (SmBMP), and all molecules colocalized in the testes. This indicates a yet unknown role of the TGFβ-pathway for schistosome biology leading to male competence and a possible influence of pairing on the male gonad.
Author Summary
Schistosomiasis is an important infectious disease caused by worm parasites of the genus Schistosoma and directly affects more than 240 million people in 78 tropical and sub-tropical countries but also animals. Pathogenesis is triggered by eggs that are produced by paired females and get trapped in liver and gut causing severe inflammation. While studies have concentrated on the reproductive biology of schistosome females in the past, not much is known about males even though they are indispensable for female sexual development and egg production. Therefore, we studied pairing-dependent processes in S. mansoni males using two independent transcriptomics approaches providing a congruent and most comprehensive data-set on genes being differentially transcribed between pairing-experienced, competent males and pairing-unexperienced, naive males. Besides confirming former studies concerning changes in metabolic processes, our results give new insights into processes leading to male competence indicating among others a potential role of neurotransmitters and TGFβ signal-transduction processes. We especially highlight the follistatin gene SmFst, which codes for an inhibitor of the TGFβ-pathway. SmFst transcription was localized in the testes and found to be down-regulated in pairing-experienced males. This indicates a yet unknown function of pairing on the male gonad and a further role of TGFβ-signaling for schistosome biology.
PMCID: PMC3820750  PMID: 24244773
5.  Long non-coding RNAs and their implications in cancer epigenetics 
Bioscience Reports  2013;33(4):e00061.
LncRNAs (long non-coding RNAs) have emerged as key molecular players in the regulation of gene expression in different biological processes. Their involvement in epigenetic processes includes the recruitment of histone-modifying enzymes and DNA methyltransferases, leading to the establishment of chromatin conformation patterns that ultimately result in the fine control of genes. Some of these genes are related to tumorigenesis and it is well documented that the misregulation of epigenetic marks leads to cancer. In this review, we highlight how some of the lncRNAs implicated in cancer are involved in the epigenetic control of gene expression. While very few lncRNAs have already been identified as players in determining the cancer-survival outcome in a number of different cancer types, for most of the lncRNAs associated with epigenetic regulation only their altered pattern of expression in cancer is demonstrated. Thanks to their tissue-specificity features, lncRNAs have already been proposed as diagnostic markers in specific cancer types. We envision the discovery of a wealth of novel spliced and unspliced intronic lncRNAs involved in epigenetic networks or in highly location-specific epigenetic control, which might be predominantly altered in specific cancer subtypes. We expect that the characterization of new lncRNA (long non-coding RNA)–protein and lncRNA–DNA interactions will contribute to the discovery of potential lncRNA targets for use in therapies against cancer.
PMCID: PMC3759304  PMID: 23875687
cancer epigenetics; intergenic lncRNA; intronic lncRNA; long non-coding RNAs; regulatory RNA; RNA-guided gene silencing; ANRASSF1, antisense non-coding RNA in the RASSF1A locus; ANRIL, antisense non-coding RNA in the INK4 locus; AR, androgen receptor; ARF, ADP-ribosylation factor; CHD, chromodomain helicase DNA-binding protein; CpG, cytosine phosphodiester bond guanine; CRC, colorectal cancer; CTBP1-AS, C-terminal binding protein 1 antisense; EZH2, enhancer of zeste homologue 2; H3K27me3, histone 3 lysine 27 trymethylated; HDAC, histone deacetylase; HDM, histone demethylase; HMT, histone methyltransferase; HOTAIR, homeobox antisense intergenic RNA; HOX, homeobox; INK4a, inhibitor of cyclin-dependent kinase 4a; INK4b, inhibitor of cyclin-dependent kinase 4b; LICR, Ludwig Institute for Cancer Research; lncRNA, long non-coding RNA; lincRNA, long intergenic non-coding RNA; LSD1, lysine (K)-specific demethylase 1A; MLL, mixed-lineage leukaemia; PCAT-1, prostate cancer-associated ncRNA transcript 1; PRC, polycomb repressive complex; PSF, phosphotyrosine-binding-associated splicing factor; RASSF1A, Ras association (RalGDS/AF-6) domain family member 1 isoform A; RNAPII, RNA polymerase II; SMARCA2, SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, type 2 (also known as BRM); XCI, X chromosome inactivation; XIST, X-inactive specific transcript
6.  The Intronic Long Noncoding RNA ANRASSF1 Recruits PRC2 to the RASSF1A Promoter, Reducing the Expression of RASSF1A and Increasing Cell Proliferation 
PLoS Genetics  2013;9(8):e1003705.
The down-regulation of the tumor-suppressor gene RASSF1A has been shown to increase cell proliferation in several tumors. RASSF1A expression is regulated through epigenetic events involving the polycomb repressive complex 2 (PRC2); however, the molecular mechanisms modulating the recruitment of this epigenetic modifier to the RASSF1 locus remain largely unknown. Here, we identify and characterize ANRASSF1, an endogenous unspliced long noncoding RNA (lncRNA) that is transcribed from the opposite strand on the RASSF1 gene locus in several cell lines and tissues and binds PRC2. ANRASSF1 is transcribed through RNA polymerase II and is 5′-capped and polyadenylated; it exhibits nuclear localization and has a shorter half-life compared with other lncRNAs that bind PRC2. ANRASSF1 endogenous expression is higher in breast and prostate tumor cell lines compared with non-tumor, and an opposite pattern is observed for RASSF1A. ANRASSF1 ectopic overexpression reduces RASSF1A abundance and increases the proliferation of HeLa cells, whereas ANRASSF1 silencing causes the opposite effects. These changes in ANRASSF1 levels do not affect the RASSF1C isoform abundance. ANRASSF1 overexpression causes a marked increase in both PRC2 occupancy and histone H3K27me3 repressive marks, specifically at the RASSF1A promoter region. No effect of ANRASSF1 overexpression was detected on PRC2 occupancy and histone H3K27me3 at the promoter regions of RASSF1C and the four other neighboring genes, including two well-characterized tumor suppressor genes. Additionally, we demonstrated that ANRASSF1 forms an RNA/DNA hybrid and recruits PRC2 to the RASSF1A promoter. Together, these results demonstrate a novel mechanism of epigenetic repression of the RASSF1A tumor suppressor gene involving antisense unspliced lncRNA, in which ANRASSF1 selectively represses the expression of the RASSF1 isoform overlapping the antisense transcript in a location-specific manner. In a broader perspective, our findings suggest that other non-characterized unspliced intronic lncRNAs transcribed in the human genome might contribute to a location-specific epigenetic modulation of genes.
Author Summary
RASSF1A is a tumor suppressor gene whose expression is repressed through epigenetic events in a wide range of different cancers. Repression is effected by DNA hypermethylation of the RASSF1A promoter, which in turn is triggered through histone H3K9/H3K27 trimethylation repressive marks. The addition of the H3K27me3 mark at the RASSF1A promoter locus involves the polycomb repressive complex 2 (PRC2). The molecular mechanisms that control the recruitment of PRC2 to the promoter to initiate H3K27 trimethylation and repress RASSF1A expression have not been described. Here, we identified a long noncoding RNA (lncRNA), termed ANRASSF1 for antisense noncoding RASSF1, that is transcribed from the opposite strand of the RASSF1A gene and is responsible for recruiting PRC2 to the RASSF1A promoter region in a highly location-specific manner. No effect of ANRASSF1 was detected on the promoter of the RASSF1C isoform or the promoters of the four other genes within the vicinity of RASSF1, including two other well-characterized tumor suppressor genes. This work provides evidence that the epigenetic modulation of the tumor suppressor gene RASSF1A is dependent on the lncRNA ANRASSF1 and highlights the importance of further studies on the involvement of ANRASSF1 in tumorigenesis.
PMCID: PMC3749938  PMID: 23990798
8.  Transcriptome Analyses of Inhibitor-treated Schistosome Females Provide Evidence for Cooperating Src-kinase and TGFβ Receptor Pathways Controlling Mitosis and Eggshell Formation 
PLoS Pathogens  2013;9(6):e1003448.
Schistosome parasites cause schistosomiasis, one of the most prevalent parasitemias worldwide affecting humans and animals. Constant pairing of schistosomes is essential for female sexual maturation and egg production, which causes pathogenesis. Female maturation involves signaling pathways controlling mitosis and differentiation within the gonads. In vitro studies had shown before that a Src-specific inhibitor, Herbimycin A (Herb A), and a TGFβ receptor (TβR) inhibitor (TRIKI) have physiological effects such as suppressed mitoses and egg production in paired females. As one Herb A target, the gonad-specifically expressed Src kinase SmTK3 was identified. Here, we comparatively analyzed the transcriptome profiles of Herb A- and TRIKI-treated females identifying transcriptional targets of Src-kinase and TβRI pathways. After demonstrating that TRIKI inhibits the schistosome TGFβreceptor SmTβRI by kinase assays in Xenopus oocytes, couples were treated with Herb A, TRIKI, or both inhibitors simultaneously in vitro. RNA was isolated from females for microarray hybridizations and transcription analyses. The obtained data were evaluated by Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA), but also by manual classification and intersection analyses. Finally, extensive qPCR experiments were done to verify differential transcription of candidate genes under inhibitor influence but also to functionally reinforce specific physiological effects. A number of genes found to be differentially regulated are associated with mitosis and differentiation. Among these were calcium-associated genes and eggshell-forming genes. In situ hybridization confirmed transcription of genes coding for the calcium sensor hippocalcin, the calcium transporter ORAI-1, and the calcium-binding protein calmodulin-4 in the reproductive system pointing to a role of calcium in parasite reproduction. Functional qPCR results confirmed an inhibitor-influenced, varying dependence of the transcriptional activities of Smp14, Smp48, fs800, a predicted eggshell precursor protein and SmTYR1. The results show that eggshell-formation is regulated by at least two pathways cooperatively operating in a balanced manner to control egg production.
Author Summary
As one of the most prevalent parasitic infections worldwide, schistosomiasis is caused by blood-flukes of the genus Schistosoma. Pathology coincides with egg production, which is started upon pairing of the dioeciously living adults. A constant pairing contact is required to induce mitoses and differentiation processes in the female leading to the development of the gonads. Although long known, the molecular processes controlling gonad development or egg-production in schistosomes or other platyhelminths are largely unknown. Using an established in vitro-culture system and specific, chemical inhibitors we have obtained first evidence in previous studies for the participation of signal transduction processes playing essential roles in controlling mitoses, differentiation and egg production. In the present study we applied combinatory inhibitor treatments combined with subsequent microarray and qPCR analyses and demonstrate for the first time that cooperating Src-Kinase- und TGFβ-signaling pathways control mitoses and egg formation processes. Besides direct evidence for managing transcription of eggshell-forming genes, new target molecules of these pathways were identified. Among these are calcium-associated genes providing a first hint towards a role of this ion for reproduction. Our finding shed first light on the signaling mechanisms controlling egg formation, which is important for life-cycling and pathology.
PMCID: PMC3681755  PMID: 23785292
9.  Effect of human TGF-β on the gene expression profile of Schistosoma mansoni adult worms 
Schistosoma mansoni is responsible for schistosomiasis, a parasitic disease that affects 200 million people worldwide. Molecular mechanisms of host-parasite interaction are complex and involve a crosstalk between host signals and parasite receptors. TGF-β signaling pathway has been shown to play an important role in S. mansoni development and embryogenesis. In particular human (h) TGF-β has been shown to bind to a S. mansoni receptor, transduce a signal that regulates the expression of a schistosome target gene. Here we describe 381 parasite genes whose expression levels are affected by in vitro treatment with hTGF-β. Among these differentially expressed genes we highlight genes related to morphology, development and cell cycle that could be players of cytokine effects on the parasite. We confirm by qPCR the expression changes detected with microarrays for 5 out of 7 selected genes. We also highlight a set of non-coding RNAs transcribed from the same loci of protein-coding genes that are differentially expressed upon hTGF-β treatment. These datasets offer potential targets to be explored in order to understand the molecular mechanisms behind the possible role of hTGF-β effects on parasite biology.
PMCID: PMC3327796  PMID: 22387759
Schistosoma mansoni; TGF-β signaling; host-parasite cross talk; microarray analysis; ncRNAs; gene network interactions
10.  Immunization with tegument nucleotidases associated with a subcurative praziquantel treatment reduces worm burden following Schistosoma mansoni challenge 
PeerJ  2013;1:e58.
Schistosomiasis is a debilitating disease caused by flatworm parasites of the Schistosoma genus and remains a high public health impact disease around the world, although effective treatment with Praziquantel (PZQ) has been available since the 1970s. Control of this disease would be greatly improved by the development of a vaccine, which could be combined with chemotherapy. The sequencing of the Schistosoma mansoni transcriptome and genome identified a range of potential vaccine antigens. Among these, three nucleotidases from the tegument of the parasite, presumably involved in purinergic signaling and nucleotide metabolism, were proposed as promising vaccine candidates: an alkaline phosphatase (SmAP), a phosphodiesterase (SmNPP-5) and a diphosphohydrolase (SmNTPDase). Herein, we evaluate the potential of these enzymes as vaccine antigens, with or without subcurative PZQ treatment. Immunization of mice with the recombinant proteins alone or in combination demonstrated that SmAP is the most immunogenic of the three. It induced the highest antibody levels, particularly IgG1, associated with an inflammatory cellular immune response characterized by high TNF-α and a Th17 response, with high IL-17 expression levels. Despite the specific immune response induced, immunization with the isolated or combined proteins did not reduce the worm burden of challenged mice. Nonetheless, immunization with SmAP alone or with the three proteins combined, together with subcurative PZQ chemotherapy was able to reduce the worm burden by around 40%. The immunogenicity and relative exposure of SmAP to the host immune system are discussed, as key factors involved in the apparently synergistic effect of SmAP immunization and subcurative PZQ treatment.
PMCID: PMC3628383  PMID: 23638396
Schistosoma mansoni; Vaccine; SmNTPDase Apyrase ATPDase; Alkaline phosphatase; Nucleotide pyrophosphatase/phosphodiesterase SmNPP NPP; Tegument; Nucleotidases; Praziquantel
11.  Perspectives of Long Non-Coding RNAs in Cancer Diagnostics 
Long non-coding RNAs (lncRNAs) transcribed from intergenic and intronic regions of the human genome constitute a broad class of cellular transcripts that are under intensive investigation. While only a handful of lncRNAs have been characterized, their involvement in fundamental cellular processes that control gene expression highlights a central role in cell homeostasis. Not surprisingly, aberrant expression of regulatory lncRNAs has been increasingly documented in different types of cancer, where they can mediate both oncogenic or tumor suppressor effects. Interaction with chromatin remodeling complexes that promote silencing of specific genes or modulation of splicing factor proteins seem to be two general modes of lncRNA regulation, but it is conceivable that additional mechanisms of action are yet to be unveiled. LncRNAs show greater tissue specificity compared to protein-coding mRNAs making them attractive in the search of novel diagnostics/prognostics cancer biomarkers in body fluid samples. In fact, lncRNA prostate cancer antigen 3 can be detected in urine samples and has been shown to improve diagnosis of prostate cancer. We suggest that an unbiased screening of the presence of RNAs in easily accessible body fluids such as serum and urine might reveal novel circulating lncRNAs as potential biomarkers in many types of cancer. Annotation and functional characterization of the lncRNA complement of the cancer transcriptome will conceivably provide new venues for early diagnosis and treatment of the disease.
PMCID: PMC3297063  PMID: 22408643
long non-coding RNA; cancer; diagnostics; expression signature
12.  Long noncoding intronic RNAs are differentially expressed in primary and metastatic pancreatic cancer 
Molecular Cancer  2011;10:141.
Pancreatic ductal adenocarcinoma (PDAC) is known by its aggressiveness and lack of effective therapeutic options. Thus, improvement in current knowledge of molecular changes associated with pancreatic cancer is urgently needed to explore novel venues of diagnostics and treatment of this dismal disease. While there is mounting evidence that long noncoding RNAs (lncRNAs) transcribed from intronic and intergenic regions of the human genome may play different roles in the regulation of gene expression in normal and cancer cells, their expression pattern and biological relevance in pancreatic cancer is currently unknown. In the present work we investigated the relative abundance of a collection of lncRNAs in patients' pancreatic tissue samples aiming at identifying gene expression profiles correlated to pancreatic cancer and metastasis.
Custom 3,355-element spotted cDNA microarray interrogating protein-coding genes and putative lncRNA were used to obtain expression profiles from 38 clinical samples of tumor and non-tumor pancreatic tissues. Bioinformatics analyses were performed to characterize structure and conservation of lncRNAs expressed in pancreatic tissues, as well as to identify expression signatures correlated to tissue histology. Strand-specific reverse transcription followed by PCR and qRT-PCR were employed to determine strandedness of lncRNAs and to validate microarray results, respectively.
We show that subsets of intronic/intergenic lncRNAs are expressed across tumor and non-tumor pancreatic tissue samples. Enrichment of promoter-associated chromatin marks and over-representation of conserved DNA elements and stable secondary structure predictions suggest that these transcripts are generated from independent transcriptional units and that at least a fraction is under evolutionary selection, and thus potentially functional.
Statistically significant expression signatures comprising protein-coding mRNAs and lncRNAs that correlate to PDAC or to pancreatic cancer metastasis were identified. Interestingly, loci harboring intronic lncRNAs differentially expressed in PDAC metastases were enriched in genes associated to the MAPK pathway. Orientation-specific RT-PCR documented that intronic transcripts are expressed in sense, antisense or both orientations relative to protein-coding mRNAs. Differential expression of a subset of intronic lncRNAs (PPP3CB, MAP3K14 and DAPK1 loci) in metastatic samples was confirmed by Real-Time PCR.
Our findings reveal sets of intronic lncRNAs expressed in pancreatic tissues whose abundance is correlated to PDAC or metastasis, thus pointing to the potential relevance of this class of transcripts in biological processes related to malignant transformation and metastasis in pancreatic cancer.
PMCID: PMC3225313  PMID: 22078386
pancreatic cancer; molecular markers; noncoding RNAs; intronic transcription; metastasis; MAPK ; pathway; cDNA microarrays
13.  Systems medicine and integrated care to combat chronic noncommunicable diseases 
Genome Medicine  2011;3(7):43.
We propose an innovative, integrated, cost-effective health system to combat major non-communicable diseases (NCDs), including cardiovascular, chronic respiratory, metabolic, rheumatologic and neurologic disorders and cancers, which together are the predominant health problem of the 21st century. This proposed holistic strategy involves comprehensive patient-centered integrated care and multi-scale, multi-modal and multi-level systems approaches to tackle NCDs as a common group of diseases. Rather than studying each disease individually, it will take into account their intertwined gene-environment, socio-economic interactions and co-morbidities that lead to individual-specific complex phenotypes. It will implement a road map for predictive, preventive, personalized and participatory (P4) medicine based on a robust and extensive knowledge management infrastructure that contains individual patient information. It will be supported by strategic partnerships involving all stakeholders, including general practitioners associated with patient-centered care. This systems medicine strategy, which will take a holistic approach to disease, is designed to allow the results to be used globally, taking into account the needs and specificities of local economies and health systems.
PMCID: PMC3221551  PMID: 21745417
14.  Identification of protein-coding and non-coding RNA expression profiles in CD34+ and in stromal cells in refractory anemia with ringed sideroblasts 
BMC Medical Genomics  2010;3:30.
Myelodysplastic syndromes (MDS) are a group of clonal hematological disorders characterized by ineffective hematopoiesis with morphological evidence of marrow cell dysplasia resulting in peripheral blood cytopenia. Microarray technology has permitted a refined high-throughput mapping of the transcriptional activity in the human genome. Non-coding RNAs (ncRNAs) transcribed from intronic regions of genes are involved in a number of processes related to post-transcriptional control of gene expression, and in the regulation of exon-skipping and intron retention. Characterization of ncRNAs in progenitor cells and stromal cells of MDS patients could be strategic for understanding gene expression regulation in this disease.
In this study, gene expression profiles of CD34+ cells of 4 patients with MDS of refractory anemia with ringed sideroblasts (RARS) subgroup and stromal cells of 3 patients with MDS-RARS were compared with healthy individuals using 44 k combined intron-exon oligoarrays, which included probes for exons of protein-coding genes, and for non-coding RNAs transcribed from intronic regions in either the sense or antisense strands. Real-time RT-PCR was performed to confirm the expression levels of selected transcripts.
In CD34+ cells of MDS-RARS patients, 216 genes were significantly differentially expressed (q-value ≤ 0.01) in comparison to healthy individuals, of which 65 (30%) were non-coding transcripts. In stromal cells of MDS-RARS, 12 genes were significantly differentially expressed (q-value ≤ 0.05) in comparison to healthy individuals, of which 3 (25%) were non-coding transcripts.
These results demonstrated, for the first time, the differential ncRNA expression profile between MDS-RARS and healthy individuals, in CD34+ cells and stromal cells, suggesting that ncRNAs may play an important role during the development of myelodysplastic syndromes.
PMCID: PMC2914047  PMID: 20633296
15.  Identification of the Schistosoma mansoni TNF-Alpha Receptor Gene and the Effect of Human TNF-Alpha on the Parasite Gene Expression Profile 
Schistosoma mansoni is the major causative agent of schistosomiasis. The parasite takes advantage of host signals to complete its development in the human body. Tumor necrosis factor-alpha (TNF-α) is a human cytokine involved in skin inflammatory responses, and although its effect on the adult parasite's metabolism and egg-laying process has been previously described, a comprehensive assessment of the TNF-α pathway and its downstream molecular effects is lacking.
Methodology/Principal Findings
In the present work we describe a possible TNF-α receptor (TNFR) homolog gene in S. mansoni (SmTNFR). SmTNFR encodes a complete receptor sequence composed of 599 amino acids, and contains four cysteine-rich domains as described for TNFR members. Real-time RT-PCR experiments revealed that SmTNFR highest expression level is in cercariae, 3.5 (±0.7) times higher than in adult worms. Downstream members of the known human TNF-α pathway were identified by an in silico analysis, revealing a possible TNF-α signaling pathway in the parasite. In order to simulate parasite's exposure to human cytokine during penetration of the skin, schistosomula were exposed to human TNF-α just 3 h after cercariae-to-schistosomula in vitro transformation, and large-scale gene expression measurements were performed with microarrays. A total of 548 genes with significantly altered expression were detected, when compared to control parasites. In addition, treatment of adult worms with TNF-α caused a significantly altered expression of 1857 genes. Interestingly, the set of genes altered in adults is different from that of schistosomula, with 58 genes in common, representing 3% of altered genes in adults and 11% in 3 h-old early schistosomula.
We describe the possible molecular elements and targets involved in human TNF-α effect on S. mansoni, highlighting the mechanism by which recently transformed schistosomula may sense and respond to this host mediator at the site of cercarial penetration into the skin.
Author Summary
Schistosoma mansoni is the major causative agent of schistosomiasis in the Americas. This parasite takes advantage of host signaling molecules such as cytokines and hormones to complete its development inside the host. Tumor necrosis factor-alpha (TNF-α) is one of the most important host cytokines involved in the inflammatory response. When cercariae, the infective stage, penetrates the human skin the release of TNF-α is started. In this work the authors describe the complete sequence of a possible TNF-α receptor in S. mansoni and detect that the receptor is most highly expressed in cercariae among all life cycle stages. Aiming to mimic the situation at the site of skin penetration, cercariae were mechanically transformed in vitro into schistosomula and exposed to human TNF-α. Exposure of early-developing schistosomula to the human hormone caused a large-scale change in the expression of parasite genes. Exposure of adult worms to human TNF-α caused gene expression changes as well, and the set of parasite altered genes in the adult parasite was different from that of schistosomula. This work increases the number of known signaling pathways of the parasite, and opens new perspectives into understanding the molecular components of TNF-α response as well as into possibly interfering with parasite–host interaction.
PMCID: PMC2779652  PMID: 19956564
16.  Gene Expression Profile of Mesenchymal Stem Cells from Paired Umbilical Cord Units: Cord is Different from Blood 
Stem Cell Reviews  2009;5(4):387-401.
Mesenchymal stem cells (MSC) are multipotent cells which can be obtained from several adult and fetal tissues including human umbilical cord units. We have recently shown that umbilical cord tissue (UC) is richer in MSC than umbilical cord blood (UCB) but their origin and characteristics in blood as compared to the cord remains unknown. Here we compared, for the first time, the exonic protein-coding and intronic noncoding RNA (ncRNA) expression profiles of MSC from match-paired UC and UCB samples, harvested from the same donors, processed simultaneously and under the same culture conditions. The patterns of intronic ncRNA expression in MSC from UC and UCB paired units were highly similar, indicative of their common donor origin. The respective exonic protein-coding transcript expression profiles, however, were significantly different. Hierarchical clustering based on protein-coding expression similarities grouped MSC according to their tissue location rather than original donor. Genes related to systems development, osteogenesis and immune system were expressed at higher levels in UCB, whereas genes related to cell adhesion, morphogenesis, secretion, angiogenesis and neurogenesis were more expressed in UC cells. These molecular differences verified in tissue-specific MSC gene expression may reflect functional activities influenced by distinct niches and should be considered when developing clinical protocols involving MSC from different sources. In addition, these findings reinforce our previous suggestion on the importance of banking the whole umbilical cord unit for research or future therapeutic use.
Electronic supplementary material
The online version of this article (doi:10.1007/s12015-009-9098-5) contains supplementary material, which is available to authorized users.
PMCID: PMC2803263  PMID: 20058202
Human umbilical cord; Human umbilical cord blood; Mesenchymal stem cells; Comparative gene expression profile
17.  Interference with Hemozoin Formation Represents an Important Mechanism of Schistosomicidal Action of Antimalarial Quinoline Methanols 
The parasitic trematode Schistosoma mansoni is one of the major causative agents of human schistosomiasis, which afflicts 200 million people worldwide. Praziquantel remains the main drug used for schistosomiasis treatment, and reliance on the single therapy has been prompting the search for new therapeutic compounds against this disease. Our group has demonstrated that heme crystallization into hemozoin (Hz) within the S. mansoni gut is a major heme detoxification route with lipid droplets involved in this process and acting as a potential chemotherapeutical target. In the present work, we investigated the effects of three antimalarial compounds, quinine (QN), quinidine (QND) and quinacrine (QCR) in a murine schistosomiasis model by using a combination of biochemical, cell biology and molecular biology approaches.
Methodology/Principal Findings
Treatment of S. mansoni-infected female Swiss mice with daily intraperitoneal injections of QN, and QND (75 mg/kg/day) from the 11th to 17th day after infection caused significant decreases in worm burden (39%–61%) and egg production (42%–98%). Hz formation was significantly inhibited (40%–65%) in female worms recovered from QN- and QND-treated mice and correlated with reduction in the female worm burden. We also observed that QN treatment promoted remarkable ultrastructural changes in male and female worms, particularly in the gut epithelium and reduced the granulomatous reaction to parasite eggs trapped in the liver. Microarray gene expression analysis indicated that QN treatment increased the expression of transcripts related to musculature, protein synthesis and repair mechanisms.
The overall significant reduction in several disease burden parameters by the antimalarial quinoline methanols indicates that interference with Hz formation in S. mansoni represents an important mechanism of schistosomicidal action of these compounds and points out the heme crystallization process as a valid chemotherapeutic target to treat schistosomiasis.
Author Summary
Heme is an essential molecule to most living organisms, but once in a free state it exerts toxic effects. Blood-feeding organisms evolved efficient ways to detoxify free heme derived from hemoglobin digestion. A key mechanism present in some hematophagous organisms consists of the crystallization of heme into a pigment named hemozoin. Schistosoma mansoni is one of the etiologic agents of human schistosomiasis, a parasitic disease that affects over 200 million people in tropical and subtropical areas. Hemozoin formation represents the main heme detoxification pathway in S. mansoni. Here, we report that the antimalarial quinoline methanols quinine and quinidine exert schistosomicidal effects notably due to their capacity to interfere with hemozoin formation. When quinine or quinidine were administered intraperitoneally during seven days to S. mansoni-infected mice (75 mg/kg/day), both worm and eggs burden were significantly reduced. Interestingly, hemozoin content in female worms was drastically affected after treatment with either compound. We also found that quinine caused important changes in the cellular organization of worm gastrodermis and increased expression of genes related to musculature, protein synthesis and repair mechanisms. Together, our results indicate that interference with hemozoin formation is a valid chemotherapeutic target for development of new schistosomicidal agents.
PMCID: PMC2703804  PMID: 19597543
18.  Influence of Ecto-Nucleoside Triphosphate Diphosphohydrolase Activity on Trypanosoma cruzi Infectivity and Virulence 
The protozoan Trypanosoma cruzi is the causative agent of Chagas disease. There are no vaccines or effective treatment, especially in the chronic phase when most patients are diagnosed. There is a clear necessity to develop new drugs and strategies for the control and treatment of Chagas disease. Recent papers have suggested the ecto-nucleotidases (from CD39 family) from pathogenic agents as important virulence factors. In this study we evaluated the influence of Ecto-Nucleoside-Triphosphate-Diphosphohydrolase (Ecto-NTPDase) activity on infectivity and virulence of T. cruzi using both in vivo and in vitro models.
Methodology/Principal Findings
We followed Ecto-NTPDase activities of Y strain infective forms (trypomastigotes) obtained during sequential sub-cultivation in mammalian cells. ATPase/ADPase activity ratios of cell-derived trypomastigotes decreased 3- to 6-fold and infectivity was substantially reduced during sequential sub-cultivation. Surprisingly, at third to fourth passages most of the cell-derived trypomastigotes could not penetrate mammalian cells and had differentiated into amastigote-like parasites that exhibited 3- to 4-fold lower levels of Ecto-NTPDase activities. To evidence the participation of T. cruzi Ecto-NTPDase1 in the infective process, we evaluated the effect of known Ecto-ATPDase inhibitors (ARL 67156, Gadolinium and Suramin), or anti-NTPDase-1 polyclonal antiserum on ATPase and ADPase hydrolytic activities in recombinant T. cruzi NTPDase-1 and in live trypomastigotes. All tests showed a partial inhibition of Ecto-ATPDase activities and a marked inhibition of trypomastigotes infectivity. Mice infections with Ecto-NTPDase-inhibited trypomastigotes produced lower levels of parasitemia and higher host survival than with non-inhibited control parasites.
Our results suggest that Ecto-ATPDases act as facilitators of infection and virulence in vitro and in vivo and emerge as target candidates in chemotherapy of Chagas disease.
Author Summary
The protozoan Trypanosoma cruzi is the causative agent of Chagas disease, an endemic zoonosis present in some countries of South and Central Americas. The World Health Organization estimates that 100 million people are at risk of acquiring this disease. The infection affects mainly muscle tissues in the heart and digestive tract. There are no vaccines or effective treatment, especially in the chronic phase when most patients are diagnosed, which makes a strong case for the development of new drugs to treat the disease. In this work we evaluate a family of proteins called Ecto-Nucleoside-Triphosphate-Diphosphohydrolase (Ecto-NTPDase) as new chemotherapy target to block T. cruzi infection in mammalian cells and in mice. We have used inhibitors and antibodies against this protein and demonstrated that T. cruzi Ecto-NTPDases act as facilitators of infection in mammalian cells and virulence factors in mice model. Two of the drugs used in this study (Suramin and Gadolinium) are currently used for other diseases in humans, supporting the possibility of their use in the treatment of Chagas disease.
PMCID: PMC2644763  PMID: 19255624
19.  Schistosoma mansoni Tegument Protein Sm29 Is Able to Induce a Th1-Type of Immune Response and Protection against Parasite Infection 
Schistosomiasis continues to be a significant public health problem. This disease affects 200 million people worldwide and almost 800 million people are at risk of acquiring the infection. Although vaccine development against this disease has experienced more failures than successes, encouraging results have recently been obtained using membrane-spanning protein antigens from the tegument of Schistosoma mansoni. Our group recently identified Sm29, another antigen that is present at the adult worm tegument surface. In this study, we investigated murine cellular immune responses to recombinant (r) Sm29 and tested this protein as a vaccine candidate.
Methods and Findings
We first show that Sm29 is located on the surface of adult worms and lung-stage schistosomula through confocal microscopy. Next, immunization of mice with rSm29 engendered 51%, 60% and 50% reduction in adult worm burdens, in intestinal eggs and in liver granuloma counts, respectively (p<0.05). Protective immunity in mice was associated with high titers of specific anti-Sm29 IgG1 and IgG2a and elevated production of IFN-γ, TNF-α and IL-12, a typical Th1 response. Gene expression analysis of worms recovered from rSm29 vaccinated mice relative to worms from control mice revealed a significant (q<0.01) down-regulation of 495 genes and up-regulation of only 22 genes. Among down-regulated genes, many of them encode surface antigens and proteins associated with immune signals, suggesting that under immune attack schistosomes reduce the expression of critical surface proteins.
This study demonstrates that Sm29 surface protein is a new vaccine candidate against schistosomiasis and suggests that Sm29 vaccination associated with other protective critical surface antigens is the next logical strategy for improving protection.
Author Summary
Schistosomiasis is the most important human helminth infection in terms of morbidity and mortality. Although the efforts to develop a vaccine against this disease have experienced failures, a new generation of surface antigens revealed by proteomic studies changed this scenario. Our group has characterized the protein Sm29 described previously as one of the most exposed and expressed antigens in the outer tegument of Schistosoma mansoni. Studies in patients living in endemic areas for schistosomiasis revealed high levels of IgG1 and IgG3 anti-Sm29 in resistant individuals. In this study, confocal microscope analysis showed Sm29 present in the surface of lung-stage schistosoluma and adult worms. Recombinant Sm29, when used as vaccine candidate, induced high levels of protection in mice. This protection was associated with a typical Th1 immune response and reduction of worm burden, liver granulomas and in intestinal eggs. Further, microarray analysis of worms recovered from vaccinated mice showed significant down-regulation of several genes encoding previously characterized vaccine candidates and/or molecules exposed on the surface, suggesting an immune evasion strategy of schistosomes under immune attack. These results demonstrated that Sm29 as one of the important antigens with potential to compose a vaccine against schistosomiasis.
PMCID: PMC2553283  PMID: 18827884
20.  Analysis of Schistosoma mansoni genes shared with Deuterostomia and with possible roles in host interactions 
BMC Genomics  2007;8:407.
Schistosoma mansoni is a blood helminth parasite that causes schistosomiasis, a disease that affects 200 million people in the world. Many orthologs of known mammalian genes have been discovered in this parasite and evidence is accumulating that some of these genes encode proteins linked to signaling pathways in the parasite that appear to be involved with growth or development, suggesting a complex co-evolutionary process.
In this work we found 427 genes conserved in the Deuterostomia group that have orthologs in S. mansoni and no members in any nematodes and insects so far sequenced. Among these genes we have identified Insulin Induced Gene (INSIG), Interferon Regulatory Factor (IRF) and vasohibin orthologs, known to be involved in mammals in mevalonate metabolism, immune response and angiogenesis control, respectively. We have chosen these three genes for a more detailed characterization, which included extension of their cloned messages to obtain full-length sequences. Interestingly, SmINSIG showed a 10-fold higher expression in adult females as opposed to males, in accordance with its possible role in regulating egg production. SmIRF has a DNA binding domain, a tryptophan-rich N-terminal region and several predicted phosphorylation sites, usually important for IRF activity. Fourteen different alternatively spliced forms of the S. mansoni vasohibin (SmVASL) gene were detected that encode seven different protein isoforms including one with a complete C-terminal end, and other isoforms with shorter C-terminal portions. Using S. mansoni homologs, we have employed a parsimonious rationale to compute the total gene losses/gains in nematodes, arthropods and deuterostomes under either the Coelomata or the Ecdysozoa evolutionary hypotheses; our results show a lower losses/gains number under the latter hypothesis.
The genes discussed which are conserved between S. mansoni and deuterostomes, probably have an ancient origin and were lost in Ecdysozoa, being still present in Lophotrochozoa. Given their known functions in Deuterostomia, it is possible that some of them have been co-opted to perform functions related (directly or indirectly) to host adaptation or interaction with host signaling processes.
PMCID: PMC2194728  PMID: 17996068
21.  Apert p.Ser252Trp Mutation in FGFR2 Alters Osteogenic Potential and Gene Expression of Cranial Periosteal Cells 
Molecular Medicine  2007;13(7-8):422-442.
Apert syndrome (AS), a severe form of craniosynostosis, is caused by dominant gain-of-function mutations in FGFR2. Because the periosteum contribution to AS cranial pathophysiology is unknown, we tested the osteogenic potential of AS periosteal cells (p.Ser252Trp mutation) and observed that these cells are more committed toward the osteoblast lineage. To delineate the gene expression profile involved in this abnormal behavior, we performed a global gene expression analysis of coronal suture periosteal cells from seven AS patients (p.Ser252Trp), and matched controls. We identified 263 genes with significantly altered expression in AS samples (118 upregulated, 145 downregulated; SNR ≥ |0.4|, P ≤ 0.05). Several upregulated genes are involved in positive regulation of cell proliferation and nucleotide metabolism, whereas several downregulated genes are involved in inhibition of cell proliferation, gene expression regulation, cell adhesion, and extracellular matrix organization, and in PIK3-MAPK cascades. AS expression profile was confirmed through real-time PCR of a selected set of genes using RNAs from AS and control cells as well as from control cells treated with high FGF2 concentration, and through the analysis of genes involved in FGF-FGFR signaling. Our results allowed us to: (a) suggest that AS periosteal cells present enhanced osteogenic potential, (b) unravel a specific gene expression signature characteristic of AS periosteal cells which may be associated with their osteogenic commitment, (c) identify a set of novel genes involved in the pathophysiology of AS or other craniosynostotic conditions, and (d) suggest for the first time that the periosteum might be involved in the pathophysiology of AS.
PMCID: PMC1952676  PMID: 17622301
22.  A quantitative view of the transcriptome of Schistosoma mansoni adult-worms using SAGE 
BMC Genomics  2007;8:186.
Five species of the genus Schistosoma, a parasitic trematode flatworm, are causative agents of Schistosomiasis, a disease that is endemic in a large number of developing countries, affecting millions of patients around the world. By using SAGE (Serial Analysis of Gene Expression) we describe here the first large-scale quantitative analysis of the Schistosoma mansoni transcriptome, one of the most epidemiologically relevant species of this genus.
After extracting mRNA from pooled male and female adult-worms, a SAGE library was constructed and sequenced, generating 68,238 tags that covered more than 6,000 genes expressed in this developmental stage. An analysis of the ordered tag-list shows the genes of F10 eggshell protein, pol-polyprotein, HSP86, 14-3-3 and a transcript yet to be identified to be the five top most abundant genes in pooled adult worms. Whereas only 8% of the 100 most abundant tags found in adult worms of S. mansoni could not be assigned to transcripts of this parasite, 46.9% of the total ditags could not be mapped, demonstrating that the 3 sequence of most of the rarest transcripts are still to be identified. Mapping of our SAGE tags to S. mansoni genes suggested the occurrence of alternative-polyadenylation in at least 13 gene transcripts. Most of these events seem to shorten the 3 UTR of the mRNAs, which may have consequences over their stability and regulation.
SAGE revealed the frequency of expression of the majority of the S. mansoni genes. Transcriptome data suggests that alternative polyadenylation is likely to be used in the control of mRNA stability in this organism. When transcriptome was compared with the proteomic data available, we observed a correlation of about 50%, suggesting that both transcriptional and post-transcriptional regulation are important for determining protein abundance in S. mansoni. The generation of SAGE tags from other life-cycle stages should contribute to reveal the dynamics of gene expression in this important parasite.
PMCID: PMC1914358  PMID: 17584941
23.  Genome mapping and expression analyses of human intronic noncoding RNAs reveal tissue-specific patterns and enrichment in genes related to regulation of transcription 
Genome Biology  2007;8(3):R43.
An analysis of the expression of 7,135 human totally intronic noncoding RNA transcripts plus the corresponding protein-coding genes using oligonucleotide arrays has identified diverse intronic RNA expression patterns, pointing to distinct regulatory roles.
RNAs transcribed from intronic regions of genes are involved in a number of processes related to post-transcriptional control of gene expression. However, the complement of human genes in which introns are transcribed, and the number of intronic transcriptional units and their tissue expression patterns are not known.
A survey of mRNA and EST public databases revealed more than 55,000 totally intronic noncoding (TIN) RNAs transcribed from the introns of 74% of all unique RefSeq genes. Guided by this information, we designed an oligoarray platform containing sense and antisense probes for each of 7,135 randomly selected TIN transcripts plus the corresponding protein-coding genes. We identified exonic and intronic tissue-specific expression signatures for human liver, prostate and kidney. The most highly expressed antisense TIN RNAs were transcribed from introns of protein-coding genes significantly enriched (p = 0.002 to 0.022) in the 'Regulation of transcription' Gene Ontology category. RNA polymerase II inhibition resulted in increased expression of a fraction of intronic RNAs in cell cultures, suggesting that other RNA polymerases may be involved in their biosynthesis. Members of a subset of intronic and protein-coding signatures transcribed from the same genomic loci have correlated expression patterns, suggesting that intronic RNAs regulate the abundance or the pattern of exon usage in protein-coding messages.
We have identified diverse intronic RNA expression patterns, pointing to distinct regulatory roles. This gene-oriented approach, using a combined intron-exon oligoarray, should permit further comparative analysis of intronic transcription under various physiological and pathological conditions, thus advancing current knowledge about the biological functions of these noncoding RNAs.
PMCID: PMC1868932  PMID: 17386095
24.  Androgen responsive intronic non-coding RNAs 
BMC Biology  2007;5:4.
Transcription of large numbers of non-coding RNAs originating from intronic regions of human genes has been recently reported, but mechanisms governing their biosynthesis and biological functions are largely unknown. In this work, we evaluated the existence of a common mechanism of transcription regulation shared by protein-coding mRNAs and intronic RNAs by measuring the effect of androgen on the transcriptional profile of a prostate cancer cell line.
Using a custom-built cDNA microarray enriched in intronic transcribed sequences, we found 39 intronic non-coding RNAs for which levels were significantly regulated by androgen exposure. Orientation-specific reverse transcription-PCR indicated that 10 of the 13 were transcribed in the antisense direction. These transcripts are long (0.5–5 kb), unspliced and apparently do not code for proteins. Interestingly, we found that the relative levels of androgen-regulated intronic transcripts could be correlated with the levels of the corresponding protein-coding gene (asGAS6 and asDNAJC3) or with the alternative usage of exons (asKDELR2 and asITGA6) in the corresponding protein-coding transcripts. Binding of the androgen receptor to a putative regulatory region upstream from asMYO5A, an androgen-regulated antisense intronic transcript, was confirmed by chromatin immunoprecipitation.
Altogether, these results indicate that at least a fraction of naturally transcribed intronic non-coding RNAs may be regulated by common physiological signals such as hormones, and further corroborate the notion that the intronic complement of the transcriptome play functional roles in the human gene-expression program.
PMCID: PMC1800835  PMID: 17263875
25.  SmTRC1, a novel Schistosoma mansoni DNA transposon, discloses new families of animal and fungi transposons belonging to the CACTA superfamily 
The CACTA (also called En/Spm) superfamily of DNA-only transposons contain the core sequence CACTA in their Terminal Inverted Repeats (TIRs) and so far have only been described in plants. Large transcriptome and genome sequence data have recently become publicly available for Schistosoma mansoni, a digenetic blood fluke that is a major causative agent of schistosomiasis in humans, and have provided a comprehensive repository for the discovery of novel genes and repetitive elements. Despite the extensive description of retroelements in S. mansoni, just a single DNA-only transposon belonging to the Merlin family has so far been reported in this organism.
We describe a novel S. mansoni transposon named SmTRC1, for S. mansoni Transposon Related to CACTA 1, an element that shares several characteristics with plant CACTA transposons. Southern blotting indicates approximately 30–300 copies of SmTRC1 in the S. mansoni genome. Using genomic PCR followed by cloning and sequencing, we amplified and characterized a full-length and a truncated copy of this element. RT-PCR using S. mansoni mRNA followed by cloning and sequencing revealed several alternatively spliced transcripts of this transposon, resulting in distinct ORFs coding for different proteins. Interestingly, a survey of complete genomes from animals and fungi revealed several other novel TRC elements, indicating new families of DNA transposons belonging to the CACTA superfamily that have not previously been reported in these kingdoms. The first three bases in the S. mansoni TIR are CCC and they are identical to those in the TIRs of the insects Aedes aegypti and Tribolium castaneum, suggesting that animal TRCs may display a CCC core sequence.
The DNA-only transposable element SmTRC1 from S. mansoni exhibits various characteristics, such as generation of multiple alternatively-spliced transcripts, the presence of terminal inverted repeats at the extremities of the elements flanked by direct repeats and the presence of a Transposase_21 domain, that suggest a distant relationship to CACTA transposons from Magnoliophyta. Several sequences from other Metazoa and Fungi code for proteins similar to those encoded by SmTRC1, suggesting that such elements have a common ancestry, and indicating inheritance through vertical transmission before separation of the Eumetazoa, Fungi and Plants.
PMCID: PMC1636069  PMID: 17090310

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