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Sökning: WFRF:(Rovira Carlos)

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1.
  • Ferrando, Carlos, et al. (författare)
  • Effects of oxygen on post-surgical infections during an individualised perioperative open-lung ventilatory strategy : a randomised controlled trial
  • 2020
  • Ingår i: British Journal of Anaesthesia. - : ELSEVIER SCI LTD. - 0007-0912 .- 1471-6771. ; 124:1, s. 110-120
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: We aimed to examine whether using a high fraction of inspired oxygen (FIO2) in the context of an individualised intra- and postoperative open-lung ventilation approach could decrease surgical site infection (SSI) in patients scheduled for abdominal surgery. Methods: We performed a multicentre, randomised controlled clinical trial in a network of 21 university hospitals from June 6, 2017 to July 19, 2018. Patients undergoing abdominal surgery were randomly assigned to receive a high (0.80) or conventional (0.3) FIO2 during the intraoperative period and during the first 3 postoperative hours. All patients were mechanically ventilated with an open-lung strategy, which included recruitment manoeuvres and individualised positive end-expiratory pressure for the best respiratory-system compliance, and individualised continuous postoperative airway pressure for adequate peripheral oxyhaemoglobin saturation. The primary outcome was the prevalence of SSI within the first 7 postoperative days. The secondary outcomes were composites of systemic complications, length of intensive care and hospital stay, and 6-month mortality. Results: We enrolled 740 subjects: 371 in the high FIO2 group and 369 in the low FIO2 group. Data from 717 subjects were available for final analysis. The rate of SSI during the first postoperative week did not differ between high (8.9%) and low (9.4%) FIO2 groups (relative risk [RR]: 0.94; 95% confidence interval [CI]: 0.59-1.50; P=0.90]). Secondary outcomes, such as atelectasis (7.7% vs 9.8%; RR: 0.77; 95% CI: 0.48-1.25; P=0.38) and myocardial ischaemia (0.6% [n=2] vs 0% [n=0]; P=0.47) did not differ between groups. Conclusions: An oxygenation strategy using high FIO2 compared with conventional FIO2 did not reduce postoperative SSIs in abdominal surgery. No differences in secondary outcomes or adverse events were found.
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2.
  • Fernandez-Calero, Tamara, et al. (författare)
  • Profiling of small RNA cargo of extracellular vesicles shed by Trypanosoma cruzi reveals a specific extracellular signature.
  • 2015
  • Ingår i: Molecular and Biochemical Parasitology. - : Elsevier BV. - 1872-9428 .- 0166-6851. ; 199:1-2, s. 19-28
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last years, an expanding family of small regulatory RNAs (e.g. microRNAs, siRNAs and piRNAs) was recognized as key players in novel forms of post-transcriptional gene regulation in most eukaryotes. However, the machinery associated with Ago/Dicer-dependent small RNA biogenesis was thought to be either entirely lost or extensively simplified in some unicellular organisms including Trypanosoma cruzi, Saccharomyces cerevisiae, Leishmania major and Plasmodium falciparum. Although the biogenesis of small RNAs from non-coding RNAs represent a minor fraction of the normal small RNA transcriptome in eukaryotic cells, they represent the unique small RNA pathways in Trypanosoma cruzi which produce different populations of small RNAs derived from tRNAs, rRNAs, sn/snoRNAs and mRNAs. These small RNAs are secreted included in extracellular vesicles and transferred to other parasites and susceptible mammalian cells. This process represents a novel form of cross-kingdom transfer of genetic material suggesting that secreted vesicles could represent new relevant pieces in life cycle transitions, infectivity and cell-to-cell communication. Here, we provide for the first time a detailed analysis of the small RNA cargo of extracellular vesicles from T. cruzi epimastigotes under nutritional stress conditions compared to the respective intracellular compartment using deep sequencing. Compared with the intracellular compartment, shed extracellular vesicles showed a specific extracellular signature conformed by distinctive patterns of small RNAs derived from rRNA, tRNA, sno/snRNAs and protein coding sequences which evidenced specific secretory small RNA processing pathways.
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3.
  • Ferrando, Carlos, et al. (författare)
  • Rationale and study design for an individualized perioperative open lung ventilatory strategy (iPROVE) : study protocol for a randomized controlled trial
  • 2015
  • Ingår i: Trials. - : Springer Science and Business Media LLC. - 1745-6215. ; 16
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Postoperative pulmonary and non-pulmonary complications are common problems that increase morbidity and mortality in surgical patients, even though the incidence has decreased with the increased use of protective lung ventilation strategies. Previous trials have focused on standard strategies in the intraoperative or postoperative period, but without personalizing these strategies to suit the needs of each individual patient and without considering both these periods as a global perioperative lung-protective approach. The trial presented here aims at comparing postoperative complications when using an individualized ventilatory management strategy in the intraoperative and immediate postoperative periods with those when using a standard protective ventilation strategy in patients scheduled for major abdominal surgery. Methods: This is a comparative, prospective, multicenter, randomized, and controlled, four-arm trial that will include 1012 patients with an intermediate or high risk for postoperative pulmonary complications. The patients will be divided into four groups: (1) individualized perioperative group: intra-and postoperative individualized strategy; (2) intraoperative individualized strategy + postoperative continuous positive airway pressure (CPAP); (3) intraoperative standard ventilation + postoperative CPAP; (4) intra-and postoperative standard strategy (conventional strategy). The primary outcome is a composite analysis of postoperative complications. Discussion: The Individualized Perioperative Open-lung Ventilatory Strategy (iPROVE) is the first multicenter, randomized, and controlled trial to investigate whether an individualized perioperative approach prevents postoperative pulmonary complications.
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4.
  • Garcia-Silva, Maria Rosa, et al. (författare)
  • A population of tRNA-derived small RNAs is actively produced in Trypanosoma cruzi and recruited to specific cytoplasmic granules
  • 2010
  • Ingår i: Molecular and Biochemical Parasitology. - : Elsevier BV. - 1872-9428 .- 0166-6851. ; 171:2, s. 64-73
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last years an expanding family of small RNAs (i.e. microRNAs, siRNAs and piRNAs) was recognized as key players in diverse forms of gene silencing and chromatin organization. Effectors functions of these small RNAs are achieved through ribonucleoprotein (RNP) complexes containing at their center an Argonaute/Piwi protein. Although these proteins and their small RNA-associated machinery can be traced back to the common ancestor of eukaryotes, this machinery seems to be entirely lost or extensively simplified in some unicellular organisms including Trypanosoma cruzi, which are unable to trigger RNAi related phenomena. Speculating about the presence of alternate small RNA-mediated pathways in these organisms, we constructed and analyzed a size-fractionated cDNA library (20-35 nt) from epimastigotes forms of T. cruzi. Our results showed the production of an abundant class of tRNA-derived small RNAs preferentially restricted to specific isoacceptors and whose production was more accentuated under nutritional stress. These small tRNAs derived preferentially from the 5' halves of mature tRNAs and were recruited to distinctive cytoplasmic granules. Our data favor the idea that tRNA cleavage is unlikely to be the consequence of non-specific degradation but a controlled process, whose biological significance remains to be elucidated. (C) 2010 Elsevier B.V. All rights reserved.
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5.
  • Garcia Silva, Maria R., et al. (författare)
  • Cloning, characterization, and subcellular localization of a Trypanosoma cruzi argonaute protein defining a new subfamily distinctive of trypanosomatids
  • 2010
  • Ingår i: Gene. - : Elsevier BV. - 1879-0038 .- 0378-1119. ; 466:1-2, s. 26-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last years an expanding family of small non-coding RNAs (sRNA) has been identified in eukaryotic genomes which behave as sequence-specific triggers for mRNA degradation, translation repression, heterochromatin formation and genome stability. To achieve their effectors functions, sRNAs associate with members of the Argonaute protein family. Argonaute proteins are segregated into three paralogous groups: the AGO-like subfamily, the PIWI-like subfamily, and the WAGO subfamily (for Worm specific AGO). Detailed phylogenetic analysis of the small RNA-related machinery components revealed that they can be traced back to the common ancestor of eukaryotes. However, this machinery seems to be lost or excessively simplified in some unicellular organisms such as Saccharomyces cerevisiae, Trypanosoma cruzi, Leishmania major and Plasmodium falciparum which are unable to utilize dsRNA to trigger degradation of target RNAs. We reported here a unique ORF encoding for an AGO/PIWI protein in T. cruzi which was expressed in all stages of its life cycle at the transcript as well as the protein level. Database search for remote homologues, revealed the presence of a divergent PAZ domain adjacent to the well supported PIWI domain. Our results strongly suggested that this unique AGO/PIWI protein from T. cruzi is a canonical Argonaute in terms of its domain architecture. We propose to reclassify all Argonaute members from trypanosomatids as a distinctive phylogenetic group representing a new subfamily of Argonaute proteins and propose the generic designation of AGO/PIWI-tryp to identify them. Inside the Trypanosomatid-specific node, AGO/PIWI-tryps were clearly segregated into two paralog groups designated as AGO-tryp and PIWI-tryp according to the presence or absence of a functional link with RNAi-related phenomena, respectively. (C) 2010 Elsevier B.V. All rights reserved.
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6.
  • Rego, Natalia, et al. (författare)
  • Comparative microRNA profiling of Trypanosoma cruzi infected human cells
  • 2023
  • Ingår i: Frontiers in cellular and infection microbiology. - 2235-2988. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Trypanosoma cruzi, the causative agent of Chagas disease, can infect almost any nucleated cell in the mammalian host. Although previous studies have described the transcriptomic changes that occur in host cells during parasite infection, the understanding of the role of post-transcriptional regulation in this process is limited. MicroRNAs, a class of short non-coding RNAs, are key players in regulating gene expression at the post-transcriptional level, and their involvement in the host-T. cruzi interplay is a growing area of research. However, to our knowledge, there are no comparative studies on the microRNA changes that occur in different cell types in response to T. cruzi infection. Methods and results: Here we investigated microRNA changes in epithelial cells, cardiomyocytes and macrophages infected with T. cruzi for 24 hours, using small RNA sequencing followed by careful bioinformatics analysis. We show that, although microRNAs are highly cell type-specific, a signature of three microRNAs -miR-146a, miR-708 and miR-1246, emerges as consistently responsive to T. cruzi infection across representative human cell types. T. cruzi lacks canonical microRNA-induced silencing mechanisms and we confirm that it does not produce any small RNA that mimics known host microRNAs. We found that macrophages show a broad response to parasite infection, while microRNA changes in epithelial and cardiomyocytes are modest. Complementary data indicated that cardiomyocyte response may be greater at early time points of infection. Conclusions: Our findings emphasize the significance of considering microRNA changes at the cellular level and complement previous studies conducted at higher organizational levels, such as heart samples. While miR-146a has been previously implicated in T. cruzi infection, similarly to its involvement in many other immunological responses, miR-1246 and miR-708 are demonstrated here for the first time. Given their expression in multiple cell types, we anticipate our work as a starting point for future investigations into their role in the post-transcriptional regulation of T. cruzi infected cells and their potential as biomarkers for Chagas disease.
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7.
  • Boele, Joost, et al. (författare)
  • PAPD5-mediated 3' adenylation and subsequent degradation of miR-21 is disrupted in proliferative disease.
  • 2014
  • Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 111:31, s. 11467-11472
  • Tidskriftsartikel (refereegranskat)abstract
    • Next-generation sequencing experiments have shown that microRNAs (miRNAs) are expressed in many different isoforms (isomiRs), whose biological relevance is often unclear. We found that mature miR-21, the most widely researched miRNA because of its importance in human disease, is produced in two prevalent isomiR forms that differ by 1 nt at their 3' end, and moreover that the 3' end of miR-21 is posttranscriptionally adenylated by the noncanonical poly(A) polymerase PAPD5. PAPD5 knockdown caused an increase in the miR-21 expression level, suggesting that PAPD5-mediated adenylation of miR-21 leads to its degradation. Exoribonuclease knockdown experiments followed by small-RNA sequencing suggested that PARN degrades miR-21 in the 3'-to-5' direction. In accordance with this model, microarray expression profiling demonstrated that PAPD5 knockdown results in a down-regulation of miR-21 target mRNAs. We found that disruption of the miR-21 adenylation and degradation pathway is a general feature in tumors across a wide range of tissues, as evidenced by data from The Cancer Genome Atlas, as well as in the noncancerous proliferative disease psoriasis. We conclude that PAPD5 and PARN mediate degradation of oncogenic miRNA miR-21 through a tailing and trimming process, and that this pathway is disrupted in cancer and other proliferative diseases.
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8.
  • Fernández-Calero, Tamara, et al. (författare)
  • Fine-tuning the metabolic rewiring and adaptation of translational machinery during an epithelial-mesenchymal transition in breast cancer cells
  • 2020
  • Ingår i: Cancer & Metabolism. - : Springer Science and Business Media LLC. - 2049-3002. ; 8, s. 8-8
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: Background: During breast cancer progression, the epithelial to mesenchymal transition has been associated with metastasis and endocrine therapy resistance; however, the underlying mechanisms remain elusive. To gain insight into this process, we studied the transition undergone by MCF7-derived cells, which is driven by the constitutive nuclear expression of a MKL1 variant devoid of the actin-binding domain (MKL1 ΔN200). We characterized the adaptive changes that occur during the MKL1-induced cellular model and focused on regulation of translation machinery and metabolic adaptation.Methods: We performed a genome-wide analysis at the transcriptional and translational level using ribosome profiling complemented with RNA-Seq and analyzed the expression of components of the translation machinery and enzymes involved in energy metabolism. NGS data were correlated with metabolomic measurements and quantification of specific mRNAs extracted from polysomes and western blots.Results: Our results reveal the expression profiles of a luminal to basal-like state in accordance with an epithelial to mesenchymal transition. During the transition, the synthesis of ribosomal proteins and that of many translational factors was upregulated. This overexpression of the translational machinery appears to be regulated at the translational level. Our results indicate an increase of ribosome biogenesis and translation activity. We detected an extensive metabolic rewiring occurring in an already "Warburg-like" context, in which enzyme isoform switches and metabolic shunts indicate a crucial role of HIF-1α along with other master regulatory factors. Furthermore, we detected a decrease in the expression of enzymes involved in ribonucleotide synthesis from the pentose phosphate pathway. During this transition, cells increase in size, downregulate genes associated with proliferation, and strongly upregulate expression of cytoskeletal and extracellular matrix genes.Conclusions: Our study reveals multiple regulatory events associated with metabolic and translational machinery adaptation during an epithelial mesenchymal-like transition process. During this major cellular transition, cells achieve a new homeostatic state ensuring their survival. This work shows that ribosome profiling complemented with RNA-Seq is a powerful approach to unveil in-depth global adaptive cellular responses and the interconnection among regulatory circuits, which will be helpful for identification of new therapeutic targets.
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9.
  • Fernández-Calero, Tamara, et al. (författare)
  • The transcriptional activities and cellular localization of the human estrogen receptor alpha are affected by the synonymous Ala87 mutation.
  • 2014
  • Ingår i: Journal of Steroid Biochemistry and Molecular Biology. - : Elsevier BV. - 1879-1220 .- 0960-0760. ; 143:Mar 4, s. 99-104
  • Tidskriftsartikel (refereegranskat)abstract
    • Until recently, synonymous mutations (which do not change amino acids) have been much neglected. Some evidence suggests that this kind of mutations could affect mRNA secondary structure or stability, translation kinetics and protein structure. To explore deeper the role of synonymous mutations, we studied their consequence on the functional activity of the estrogen receptor alpha (ERα). The ERα is a ligand-inducible transcription factor that orchestrates pleiotropic cellular effects, at both genomic and non-genomic levels in response to estrogens. In this work we analyzed in transient transfection experiments, the activity of ERα carrying the synonymous mutation Ala87, a polymorphism involving about 5-10% of the population. In comparison to the wild type receptor, our results show that ERαA87 mutation reduces the transactivation efficiency of ERα on an ERE reporter gene while its expression level remains similar. This mutation enhances 4-OHT-induced transactivation of ERα on an AP1 reporter gene. Finally, the mutation affects the subcellular localization of ERα in a cell type specific manner. It enhances the cytoplasmic location of ERα without significant changes in non-genomic effects of E2. The functional alteration of the ERαA87 determined in this work highlights the relevance of synonymous mutations for biomedical and pharmacological points of view.
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10.
  • Ferrando, Carlos, et al. (författare)
  • Individualised perioperative open-lung approach versus standard protective ventilation in abdominal surgery (iPROVE) : a randomised controlled trial
  • 2018
  • Ingår i: The Lancet Respiratory Medicine. - : ELSEVIER SCI LTD. - 2213-2600 .- 2213-2619. ; 6:3, s. 193-203
  • Tidskriftsartikel (refereegranskat)abstract
    • Background The effects of individualised perioperative lung-protective ventilation (based on the open-lung approach [OLA]) on postoperative complications is unknown. We aimed to investigate the effects of intraoperative and postoperative ventilatory management in patients scheduled for abdominal surgery, compared with standard protective ventilation. Methods We did this prospective, multicentre, randomised controlled trial in 21 teaching hospitals in Spain. We enrolled patients who were aged 18 years or older, were scheduled to have abdominal surgery with an expected time of longer than 2 h, had intermediate-to-high-risk of developing postoperative pulmonary complications, and who had a body-mass index less than 35 kg/m(2). Patients were randomly assigned (1: 1: 1: 1) online to receive one of four lung-protective ventilation strategies using low tidal volume plus positive end-expiratory pressure (PEEP): open-lung approach (OLA)-iCPAP (individualised intraoperative ventilation [individualised PEEP after a lung recruitment manoeuvre] plus individualised postoperative continuous positive airway pressure [CPAP]), OLA-CPAP (intraoperative individualised ventilation plus postoperative CPAP), STD-CPAP (standard intraoperative ventilation plus postoperative CPAP), or STD-O-2 (standard intraoperative ventilation plus standard postoperative oxygen therapy). Patients were masked to treatment allocation. Investigators were not masked in the operating and postoperative rooms; after 24 h, data were given to a second investigator who was masked to allocations. The primary outcome was a composite of pulmonary and systemic complications during the first 7 postoperative days. We did the primary analysis using the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02158923. Findings Between Jan 2, 2015, and May 18, 2016, we enrolled 1012 eligible patients. Data were available for 967 patients, whom we included in the final analysis. Risk of pulmonary and systemic complications did not differ for patients in OLA-iCPAP (110 [46%] of 241, relative risk 0.89 [95% CI 0.74-1.07; p=0.25]), OLA-CPAP (111 [47%] of 238, 0.91 [0.76-1.09; p=0.35]), or STD-CPAP groups (118 [48%] of 244, 0.95 [0.80-1.14; p=0.65]) when compared with patients in the STD-O-2 group (125 [51%] of 244). Intraoperatively, PEEP was increased in 69 (14%) of patients in the standard perioperative ventilation groups because of hypoxaemia, and no patients from either of the OLA groups required rescue manoeuvres. Interpretation In patients who have major abdominal surgery, the different perioperative open lung approaches tested in this study did not reduce the risk of postoperative complications when compared with standard lung-protective mechanical ventilation.
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11.
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12.
  • Gorbatenko, Andrej, et al. (författare)
  • HER2 and p95HER2 differentially regulate miRNA expression in MCF-7 breast cancer cells and downregulate MYB proteins through miR-221/222 and miR-503
  • 2019
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The HER2 oncogene and its truncated form p95HER2 play central roles in breast cancer. Here, we show that although HER2 and p95HER2 generally elicit qualitatively similar changes in miRNA profile in MCF-7 breast cancer cells, a subset of changes are distinct and p95HER2 shifts the miRNA profile towards the basal breast cancer subtype. High-throughput miRNA profiling was carried out 15, 36 and 60 h after HER2 or p95HER2 expression and central hits validated by RT-qPCR. miRNAs strongly regulated by p95HER2 yet not by HER2, included miR-221, miR-222, miR-503, miR-29a, miR-149, miR-196 and miR-361. Estrogen receptor-α (ESR1) expression was essentially ablated by p95HER2 expression, in a manner recapitulated by miR-221/-222 mimics. c-Myb family transcription factors MYB and MYBL1, but not MYBL2, were downregulated by p95HER2 and by miR-503 or miR-221/-222 mimics. MYBL1 3′UTR inhibition by miR-221/222 was lost by deletion of a single putative miR-221/222 binding sites. p95HER2 expression, or knockdown of either MYB protein, elicited upregulation of tissue inhibitor of matrix metalloprotease-2 (TIMP2). miR-221/222 and -503 mimics increased, and TIMP2 knockdown decreased, cell migration and invasion. A similar pathway was operational in T47D- and SKBr-3 cells. This work reveals important differences between HER2- and p95HER2- mediated miRNA changes in breast cancer cells, provides novel mechanistic insight into regulation of MYB family transcription factors by p95HER2, and points to a role for a miR-221/222– MYB family–TIMP2 axis in regulation of motility in breast cancer cells.
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13.
  • Hafstað, Völundur, et al. (författare)
  • Regulatory networks and 5 partner usage of miRNA host gene fusions in breast cancer
  • 2022
  • Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 151:1, s. 95-106
  • Tidskriftsartikel (refereegranskat)abstract
    • Genomic rearrangements in cancer cells can create gene fusions where the juxtaposition of two different genes leads to the production of chimeric proteins or altered gene expression through promoter-swapping. We have previously shown that fusion transcripts involving microRNA (miRNA) host genes contribute to deregulation of miRNA expression regardless of the protein-coding potential of these transcripts. Many different genes can also be used as 5 partners by a miRNA host gene in what we named recurrent miRNA-convergent fusions. Here, we have explored the properties of 5 partners in fusion transcripts that involve miRNA hosts in breast tumours from The Cancer Genome Atlas (TCGA). We hypothesised that firstly, 5 partner genes should belong to pathways and transcriptional programmes that reflect the tumour phenotype and secondly, there should be a selection for fusion events that shape miRNA expression to benefit the tumour cell through the known hallmarks of cancer. We found that the set of 5 partners in miRNA host fusions is non-random, with overrepresentation of highly expressed genes in pathways active in cancer including epithelial-to-mesenchymal transition, translational regulation and oestrogen signalling. Furthermore, many miRNAs were upregulated in samples with host gene fusions, including established onco-genic miRNAs such as mir-21 and the mir-106b similar to mir-93 similar to mir-25 cluster. To the list of mechanisms for deregulation of miRNA expression, we have added fusion transcripts that change the promoter region. We propose that this adds material for genetic selection and tumour evolution in cancer cells and that miRNA host fusions can act as tumour drivers.
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14.
  • Horjales, Sofia, et al. (författare)
  • Translational machinery and protein folding: Evidence of conformational variants of the estrogen receptor alpha
  • 2007
  • Ingår i: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 467:2, s. 139-143
  • Tidskriftsartikel (refereegranskat)abstract
    • As an approach to understand how translation may affect protein folding, we analyzed structural and functional properties of the human estrogen receptor alpha synthesized by different eukaryotic translation systems. A minimum of three conformations of the receptor were detected using limited proteolysis and a sterol ligand-binding assay. The receptor in vitro translated in rabbit reticulocyte lysate was rapidly degraded by protease, produced major bands of about 34 kDa and showed a high affinity for estradiol. In a wheat germ translation system, the receptor was more slowly digested. Two soluble co-existing conformations were evident by different degradation patterns and estradiol binding. Our data show that differences in the translation machinery may result in alternative conformations of the receptor with distinct sterol binding properties. These studies suggest that components of the cellular translation machinery itself might influence the protein folding pathways and the relative abundance of different receptor conformers. (C) 2007 Published by Elsevier Inc.
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15.
  • Kvist, Anders, et al. (författare)
  • Promoter usage of BRCA1-IRIS
  • 2005
  • Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 7:4, s. 325-326
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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16.
  • Marton, S, et al. (författare)
  • Small RNAs analysis in CLL reveals a deregulation of miRNA expression and novel miRNA candidates of putative relevance in CLL pathogenesis
  • 2008
  • Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 22:2, s. 330-338
  • Tidskriftsartikel (refereegranskat)abstract
    • MicroRNAs (miRNAs) are a novel class of small noncoding RNA molecules that regulate gene expression by inducing degradation or translational inhibition of target mRNAs. There are more than 500 miRNA genes reported in the human genome, constituting one of the largest classes of regulatory genes. Increasing experimental evidence supports the idea of aberrant miRNA expression in cancer pathogenesis. We analyzed the pattern of miRNA expression in chronic lymphocytic leukemia (CLL) cells and our results showed a global reduction in miRNA expression levels in CLL cells associated to a consistent underexpression of miR-181a, let-7a and miR-30d. We observed overexpression of miR-155 and a set of five miRNAs that are differentially expressed between patients with different clinical outcomes. Five novel miRNA candidates cloned from leukemic cells are reported. Surprisingly, predicted mRNA targets for these novel miRNA revealed a high proportion of targets located in a small region of chromosome
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17.
  • Marzouka, Nour Al Dain, et al. (författare)
  • A validation and extended description of the Lund taxonomy for urothelial carcinoma using the TCGA cohort
  • 2018
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Global gene expression analysis has been a major tool for urothelial carcinoma subtype discovery. This approach has revealed extensive complexity both in intrinsic features of the tumor cells and in the microenvironment. However, global gene expression cannot distinguish between gene expression signals originating from the tumor cells proper and from normal cells in the biopsy. Here, we use a large cohort of advanced urothelial carcinomas for which both gene expression data and extensive immunohistochemistry are available to create a supervised mRNA expression centroid classifier. This classifier identifies the major Lund taxonomy tumor cell phenotypes as defined by IHC. We apply this classifier to the independent TCGA dataset and show excellent associations between identified subtypes and genomic features. We validate a progressed version of Urothelial-like A (UroA-Prog) that shows FGFR3 mutations and CDKN2A deletions, and we show that the variant Urothelial-like C is almost devoid of FGFR3 mutations. We show that Genomically Unstable tumors are very distinct from Urothelial-like tumors at the genomic level, and that tumors classified as Basal/SCC-like all complied with the established definition for Basal/SCC-like tumors. We identify the Mesenchymal-like and Small-cell/Neuroendocrine-like subtypes, and demonstrate that patients with UroB and Sc/NE-like tumors show the worst overall survival.
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18.
  • Newie, Inga, et al. (författare)
  • HER2-encoded mir-4728 forms a receptor-independent circuit with miR-21-5p through the non-canonical poly(A) polymerase PAPD5
  • 2016
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
  • Tidskriftsartikel (refereegranskat)abstract
    • We previously reported that the human HER2 gene encodes the intronic microRNA mir-4728, which is overexpressed together with its oncogenic host gene and may act independently of the HER2 receptor. More recently, we also reported that the oncogenic miR-21-5p is regulated by 3′ tailing and trimming by the non-canonical poly(A) polymerase PAPD5 and the ribonuclease PARN. Here we demonstrate a dual function for the HER2 locus in upregulation of miR-21-5p; while HER2 signalling activates transcription of mir-21, miR-4728-3p specifically stabilises miR-21-5p through inhibition of PAPD5. Our results establish a new and unexpected oncogenic role for the HER2 locus that is not currently being targeted by any anti-HER2 therapy.
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19.
  • Newie, Inga, et al. (författare)
  • The HER2-Encoded miR-4728-3p Regulates ESR1 through a Non-Canonical Internal Seed Interaction.
  • 2014
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Since the early 1980s remarkable progress has been made in understanding the role of the HER2 locus in carcinogenesis, but many details of its regulatory network are still elusive. We recently reported the finding of 367 new human microRNA (miRNA) genes of which one, mir-4728, is encoded in an intron of the HER2 gene. Here, we confirm that the HER2 oncogene is a bi-functional locus encoding the membrane receptor and a functional miRNA gene. We further show that miR-4728-3p has alternative functionalities depending on the region used for interaction with its target; the canonical seed between nucleotides 2-8 or a novel, more internal seed shifted to nucleotides 6-12. Analysis of public data shows that this internal seed region, although rare compared to the far more abundant canonical 2-8 seed interaction, can also direct targeted down-regulation by other miRNAs. Through the internal seed, miR-4728-3p regulates expression of estrogen receptor alpha, an interaction that would have remained undetected if classic rules for miRNA-target interaction had been applied. In summary, we present here an alternative mode of miRNA regulation and demonstrate this dual function of the HER2 locus, linking the two major biomarkers in breast cancer.
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20.
  • Olsson, Oskar, et al. (författare)
  • Expression of MicroRNAs Is Dysregulated by HIV While Mycobacterium tuberculosis Drives Alterations of Small Nucleolar RNAs in HIV Positive Adults With Active Tuberculosis
  • 2022
  • Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • HIV infection affects the course of tuberculosis (TB), and HIV and Mycobacterium tuberculosis (Mtb) synergize in disease progression through complex immunological interplay. To gain further understanding of these mechanisms, we compared the microRNA (miRNA) and small nucleolar RNA (snoRNA) expression patterns in whole blood of individuals with active TB, with and without HIV coinfection (HIV+/TB+ and HIV-/TB+), and HIV and TB-negative individuals (HIV-/TB-). We found that 218 miRNAs were differentially expressed between HIV+/TB+ and HIV-/TB+, while no statistically significant difference in snoRNA expression was observed between these groups. In contrast, both miRNA (n = 179) and snoRNA (n = 103) expression patterns were significantly altered in HIV+/TB+ individuals compared to those of the HIV-/TB- controls. Of note, 26 of these snoRNAs were also significantly altered between the HIV-/TB+ and HIV-/TB- groups. Normalization toward the miRNA and snoRNA expression patterns of the HIV-/TB- control group was noted during anti-TB and antiretroviral treatment in HIV+/TB+ participants. In summary, these results show that HIV coinfection influences miRNA expression in active TB. In contrast, snoRNA expression patterns differ between individuals with and without active TB, independently of HIV coinfection status. Moreover, in coinfected individuals, therapy-induced control of HIV replication and clearance of Mtb appears to normalize the expression of some small non-coding RNA (sncRNA). These findings suggest that dysregulation of miRNA is a mechanism by which HIV may modify immunity against TB, while active TB alters snoRNA expression. Improved understanding of how regulation of sncRNA expression influences the disease course in coinfected individuals may have implications for diagnostics, risk stratification, and host-directed therapy. Here, we propose a novel mechanism by which HIV alters the immune response to TB.
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21.
  • Persson, Helena, et al. (författare)
  • Analysis of fusion transcripts indicates widespread deregulation of snoRNAs and their host genes in breast cancer
  • 2020
  • Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 146:12, s. 3343-3353
  • Tidskriftsartikel (refereegranskat)abstract
    • Genomic rearrangements in cancer can join the sequences of two separate genes. Studies of such gene fusion events have mainly focused on identification of fusion proteins from the chimeric transcripts. We have previously investigated how fusions instead can affect the expression of intronic microRNA (miRNA) genes that are encoded within fusion gene partners. Here, we extend our analysis to small nucleolar RNAs (snoRNAs) that also are embedded within protein-coding or non-coding host genes. We found that snoRNA hosts are selectively enriched in fusion transcripts, like miRNA host genes, and that this enrichment is associated with all snoRNA classes. These structural changes may have functional consequences for the cell; proteins involved in the protein translation machinery are overrepresented among snoRNA host genes, a gene architecture assumed to be needed for closely coordinated expression of snoRNAs and host proteins. Our data indicate that this structure is frequently disrupted in cancer. We furthermore observed that snoRNA genes involved in fusions tend to associate with stronger promoters than the natural host, suggesting a mechanism that selects for snoRNA overexpression. In summary, we highlight a previously unexplored frequent structural change in cancer that affects important components of cellular physiology. This article is protected by copyright. All rights reserved.
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22.
  • Persson, Helena, et al. (författare)
  • Frequent miRNA-convergent fusion gene events in breast cancer
  • 2017
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies of fusion genes have mainly focused on the formation of fusions that result in the production of hybrid proteins or, alternatively, on promoter-switching events that put a gene under the control of aberrant signals. However, gene fusions may also disrupt the transcriptional control of genes that are encoded in introns downstream of the breakpoint. By ignoring structural constraints of the transcribed fusions, we highlight the importance of a largely unexplored function of fusion genes. Here, we show, using breast cancer as an example, that miRNA host genes are specifically enriched in fusion genes and that many different, low-frequency, 5 partners may deregulate the same miRNA irrespective of the coding potential of the fusion transcript. These results indicate that the concept of recurrence, defined by the rate of functionally important aberrations, needs to be revised to encompass convergent fusions that affect a miRNA independently of transcript structure and protein-coding potential.
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23.
  • Persson, Helena, et al. (författare)
  • Identification of new microRNAs in paired normal and tumor breast tissue suggests a dual role for the ERBB2/Her2 gene.
  • 2011
  • Ingår i: Cancer Research. - 1538-7445. ; 71:1, s. 78-86
  • Tidskriftsartikel (refereegranskat)abstract
    • To comprehensively characterize microRNA (miRNA) expression in breast cancer, we performed the first extensive next-generation sequencing expression analysis of this disease. We sequenced small RNA from tumors with paired samples of normal and tumor-adjacent breast tissue. Our results indicate that tumor identity is achieved mainly by variation in the expression levels of a common set of miRNAs rather than by tissue-specific expression. We also report 361 new, well-supported miRNA precursors. Nearly two-thirds of these new genes were detected in other human tissues and 49% of the miRNAs were found associated with Ago2 in MCF7 cells. Ten percent of the new miRNAs are located in regions with high-level genomic amplifications in breast cancer. A new miRNA is encoded within the ERBB2/Her2 gene and amplification of this gene leads to overexpression of the new miRNA, indicating that this potent oncogene and important clinical marker may have two different biological functions. In summary, our work substantially expands the number of known miRNAs and highlights the complexity of small RNA expression in breast cancer.
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24.
  • Persson, Helena, et al. (författare)
  • Preparation of highly multiplexed small RNA sequencing libraries
  • 2017
  • Ingår i: BioTechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 63:2, s. 57-64
  • Tidskriftsartikel (refereegranskat)abstract
    • MicroRNAs (miRNAs) are ~22-nucleotide-long small non-coding RNAs that regulate the expression of protein-coding genes by base pairing to partially complementary target sites, preferentially located in the 3´ untranslated region (UTR) of target mRNAs. The expression and function of miRNAs have been extensively studied in human disease, as well as the possibility of using these molecules as biomarkers for prognostication and treatment guidance. To identify and validate miRNAs as biomarkers, their expression must be screened in large collections of patient samples. Here, we develop a scalable protocol for the rapid and economical preparation of a large number of small RNA sequencing libraries using dual indexing for multiplexing. Combined with the use of off-the-shelf reagents, more samples can be sequenced simultaneously on large-scale sequencing platforms at a considerably lower cost per sample. Sample preparation is simplified by pooling libraries prior to gel purification, which allows for the selection of a narrow size range while minimizing sample variation. A comparison with publicly available data from benchmarking of miRNA analysis platforms showed that this method captures absolute and differential expression as effectively as commercially available alternatives.
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25.
  • Persson, Helena, et al. (författare)
  • The non-coding RNA of the multidrug resistance-linked vault particle encodes multiple regulatory small RNAs.
  • 2009
  • Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 11:10, s. 1268-1271
  • Tidskriftsartikel (refereegranskat)abstract
    • Vault particles are conserved organelles implicated in multidrug resistance and intracellular transport. They contain three different proteins and non-coding vault RNAs (vRNAs). Here we show that human vRNAs produce several small RNAs (svRNAs) by mechanisms different from those in the canonical microRNA (miRNA) pathway. At least one of these svRNAs, svRNAb, associates with Argonaute proteins to guide sequence-specific cleavage and regulate gene expression similarly to miRNAs. We demonstrate that svRNAb downregulates CYP3A4, a key enzyme in drug metabolism. Our findings expand the repertoire of small regulatory RNAs and assign, for the first time, a function to vRNAs that may help explain the association between vault particles and drug resistance.
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26.
  • Rego, Natalia, et al. (författare)
  • Search for an aetiological virus candidate in chronic lymphocytic leukaemia by extensive transcriptome analysis
  • 2012
  • Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048. ; 157:6, s. 709-717
  • Tidskriftsartikel (refereegranskat)abstract
    • As an approach to determining the aetiology of chronic lymphocytic leukaemia (CLL), we searched for a virus expressed in human CLL B-cells by combining high-throughput sequencing and digital subtraction. Pooled B-cell mRNA transcriptomes from five CLL patients and five healthy donors were sequenced with 454 Life Sciences technology. Human reads were excluded by BLAST (Basic Local Alignment Search Tool) and BLAT (BLAST-like alignment tool) searches. Remaining reads were screened with BLAST against viral databases. Purified B-cells from two CLL patients, with and without stimulation by phorbol-esters, were sequenced using Illumina technology to achieve depth of sequencing. Burrows-Wheeler Aligner mapping and BLAST searches were used for the Illumina data. Pyrosequencing resulted in about 400 similar to 000 reads per sample. No viral candidate could be found. Illumina single-end sequencing for 115 cycles yielded an average of 26 +/- 2.5million filtered reads per sample, of which 2.2 +/- 0.6 similar to million remained unmapped to human references. BLAST searches of these reads against viral and human databases assigned nine reads to an Epstein-Barr virus origin, in one sample following phorbol-ester stimulation. Other reads showing a putative viral origin were dismissed after further analysis. Despite an in-depth analysis of the CLL transcriptome reaching more than 100 similar to million sequences, we have not found evidence for a putative viral candidate in CLL.
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27.
  • Rovira, Carlos, et al. (författare)
  • MicroRNAs and other small silencing RNAs in cancer.
  • 2010
  • Ingår i: IUBMB Life. - : Wiley. - 1521-6543. ; 62:12, s. 859-868
  • Tidskriftsartikel (refereegranskat)abstract
    • Small noncoding RNAs are key controllers of cellular function, and their deregulation can lead to cancer development and metastatic evolution. This review summarizes the most important examples of small RNAs involved in human cancer and discusses their clinical use as biomarkers and drug targets for diagnosis, prognosis, and treatment of cancer. We also describe the possible mechanisms underlying small RNA-mediated transformation and outline the future describing new small RNA families with great potential in cancer biology. © 2010 IUBMB IUBMB Life, 2010.
  •  
28.
  • Rovira, Carlos (författare)
  • miRNA-convergent gene fusions
  • 2018
  • Ingår i: Molecular and Cellular Oncology. - : Informa UK Limited. - 2372-3556. ; 5:1
  • Tidskriftsartikel (refereegranskat)abstract
    • In a recent study published in Nature Communications, we showed that intron-encoded microRNA genes (miRNA) are frequent partners of fusion genes in the cancer genome. Analyzed from a functional rather than structural perspective, these rearrangements represent a new class of fusions we called “miRNA-convergent fusions”.
  •  
29.
  • Sökilde, Rolf, et al. (författare)
  • Passenger strand loading in overexpression experiments using microRNA mimics.
  • 2015
  • Ingår i: RNA Biology. - : Informa UK Limited. - 1547-6286 .- 1555-8584. ; 12:8, s. 787-791
  • Tidskriftsartikel (refereegranskat)abstract
    • MicroRNAs (miRNAs) are important regulators of gene function and manipulation of miRNAs is a central component of basic research. Modulation of gene expression by miRNA gain-of-function can be based on different approaches including transfection with miRNA mimics; artificial, chemically modified miRNA-like small RNAs. These molecules are intended to mimic the function of a miRNA guide strand while bypassing the maturation steps of endogenous miRNAs. Due to easy accessibility through commercial providers this approach has gained popularity, and accuracy is often assumed without prior independent testing. Our in silico analysis of over-represented sequence motifs in microarray expression data and sequencing of AGO-associated small RNAs indicate, however, that miRNA mimics may be associated with considerable side-effects due to the unwanted activity of the miRNA mimic complementary strand.
  •  
30.
  • Søkilde, Rolf, et al. (författare)
  • Refinement of breast cancer molecular classification by miRNA expression profiles
  • 2019
  • Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 20:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Accurate classification of breast cancer using gene expression profiles has contributed to a better understanding of the biological mechanisms behind the disease and has paved the way for better prognostication and treatment prediction.RESULTS: We found that miRNA profiles largely recapitulate intrinsic subtypes. In the case of HER2-enriched tumors a small set of miRNAs including the HER2-encoded mir-4728 identifies the group with very high specificity. We also identified differential expression of the miR-99a/let-7c/miR-125b miRNA cluster as a marker for separation of the Luminal A and B subtypes. High expression of this miRNA cluster is linked to better overall survival among patients with Luminal A tumors. Correlation between the miRNA cluster and their precursor LINC00478 is highly significant suggesting that its expression could help improve the accuracy of present day's signatures.CONCLUSIONS: We show here that miRNA expression can be translated into mRNA profiles and that the inclusion of miRNA information facilitates the molecular diagnosis of specific subtypes, in particular the clinically relevant sub-classification of luminal tumors.
  •  
31.
  • Tosar, Juan Pablo, et al. (författare)
  • Mining of public sequencing databases supports a non-dietary origin for putative foreign miRNAs: underestimated effects of contamination in NGS
  • 2014
  • Ingår i: RNA. - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 20:6, s. 754-757
  • Tidskriftsartikel (refereegranskat)abstract
    • The report that exogenous plant miRNAs are able to cross the mammalian gastrointestinal tract and exert gene-regulation mechanism in mammalian tissues has yielded a lot of controversy, both in the public press and the scientific literature. Despite the initial enthusiasm, reproducibility of these results was recently questioned by several authors. To analyze the causes of this unease, we searched for diet-derived miRNAs in deep-sequencing libraries performed by ourselves and others. We found variable amounts of plant miRNAs in publicly available small RNA-seq data sets of human tissues. In human spermatozoa, exogenous RNAs reached extreme, biologically meaningless levels. On the contrary, plant miRNAs were not detected in our sequencing of human sperm cells, which was performed in the absence of any known sources of plant contamination. We designed an experiment to show that cross-contamination during library preparation is a source of exogenous RNAs. These contamination-derived exogenous sequences even resisted oxidation with sodium periodate. To test the assumption that diet-derived miRNAs were actually contamination-derived, we sought in the literature for previous sequencing reports performed by the same group which reported the initial finding. We analyzed the spectra of plant miRNAs in a small RNA sequencing study performed in amphioxus by this group in 2009 and we found a very strong correlation with the plant miRNAs which they later reported in human sera. Even though contamination with exogenous sequences may be easy to detect, cross-contamination between samples from the same organism can go completely unnoticed, possibly affecting conclusions derived from NGS transcriptomics.
  •  
32.
  • Vallon-Christersson, Johan, et al. (författare)
  • Non-coding antisense transcription detected by conventional and single-stranded cDNA microarray
  • 2007
  • Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Recent studies revealed that many mammalian protein- coding genes also transcribe their complementary strands. This phenomenon raises questions regarding the validity of data obtained from double-stranded cDNA microarrays since hybridization to both strands may occur. Here, we wanted to analyze experimentally the incidence of antisense transcription in human cells and to estimate their influence on protein coding expression patterns obtained by double-stranded microarrays. Therefore, we profiled transcription of sense and antisense independently by using strand-specific cDNA microarrays. Results: Up to 88% of expressed protein coding loci displayed concurrent expression from the complementary strand. Antisense transcription is cell specific and showed a strong tendency to be positively correlated to the expression of the sense counterparts. Even if their expression is widespread, detected antisense signals seem to have a limited distorting effect on sense profiles obtained with double-stranded probes. Conclusion: Antisense transcription in humans can be far more common than previously estimated. However, it has limited influence on expression profiles obtained with conventional cDNA probes. This can be explained by a biological phenomena and a bias of the technique: a) a co-ordinate sense and antisense expression variation and b) a bias for sense-hybridization to occur with more efficiency, presumably due to variable exonic overlap between antisense transcripts.
  •  
33.
  • Veerla, Srinivas, et al. (författare)
  • MiRNA expression in urothelial carcinomas: Important roles of miR-10a, miR-222, miR-125b, miR-7 and miR-452 for tumor stage and metastasis, and frequent homozygous losses of miR-31.
  • 2009
  • Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 124, s. 2236-2242
  • Tidskriftsartikel (refereegranskat)abstract
    • We analyzed 34 cases of urothelial carcinomas by miRNA, mRNA and genomic profiling. Unsupervised hierarchical clustering using expression information for 300 miRNAs produced 3 major clusters of tumors corresponding to Ta, T1 and T2-T3 tumors, respectively. A subsequent SAM analysis identified 51 miRNAs that discriminated the 3 pathological subtypes. A score based on the expression levels of the 51 miRNAs, identified muscle invasive tumors with high precision and sensitivity. MiRNAs showing high expression in muscle invasive tumors included miR-222 and miR-125b and in Ta tumors miR-10a. A miRNA signature for FGFR3 mutated cases was also identified with miR-7 as an important member. MiR-31, located in 9p21, was found to be homozygously deleted in 3 cases and miR-452 and miR-452* were shown to be over expressed in node positive tumors. In addition, these latter miRNAs were shown to be excellent prognostic markers for death by disease as outcome. The presented data shows that pathological subtypes of urothelial carcinoma show distinct miRNA gene expression signatures. (c) 2009 Wiley-Liss, Inc.
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34.
  • Vera, Carlos, et al. (författare)
  • Validation of a Qualification Procedure Applied to the Verification of Partial Discharge Analysers Used for HVDC or HVAC Networks
  • 2023
  • Ingår i: Applied Sciences. - : Multidisciplinary Digital Publishing Institute (MDPI). - 2076-3417. ; 13:14
  • Tidskriftsartikel (refereegranskat)abstract
    • The insulation condition of HVDC grids consisting of cable systems, GIS, and converters should be monitored by partial discharge (PD) analysers using artificial intelligence (AI) tools for efficient insulation diagnosis. Although there are many experiences of PD monitoring solutions developed for the supervision of the insulation condition of HVAC grids using PD analysers, there are no standardised requirements for their qualification available yet. The international technical specification TS IEC 62478 provides general rules for PD measurements using electromagnetic methods but does not define performance requirements for qualification tests. HVDC and HVAC PD analysers must be tested by unambiguous test procedures. This paper compiles experiences of using PD analysers with HFCT sensors in HVAC grids (cable systems, GIS, and AIS) to define a qualification procedure for HVAC systems. This procedure is applicable to HVDC grids (cable systems, GIS, AIS, and converters) because the particularities related to the insulation behaviour under HVDC voltage are also considered. Representative PD sources are discussed in HVAC and HVDC positive and negative polarity. The PD pulse trend of representative insulation defects in HVDC cable systems is quite different from that of HVAC grids. Special attention should be paid to the acquisition of PD signals in HVDC grids since few pulses appear in solid insulations, mainly during voltage changes (polarity reversals or surges), but rarely in continuous operation with constant direct voltage. A synthetic PD simulator has been developed to reproduce trains of PD pulses or noise signals, similar to those that can appear in the power network. A set of three functionality tests has been developed for qualification of the diagnostic capabilities of PD analysers working up to 30 MHz addressed to HVDC or HVAC grids: (1) PD recognition test, (2) PD clustering test, and (3) PD location test. This qualification procedure has been validated by means of a round-robin test performed by five research institutes (RISE, FFII, TUDelft, TAU, and UPM) using commercial and in-development AI PD recognition and clustering tools to demonstrate its robustness and applicability. Applying this qualification procedure, two PD methods for electrical detection and prevention of insulation defects have been approved, one for HVAC and the other for HVDC grids. © 2023 by the authors.
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