Application Of Next-generation Sequencing Techniques Research Articles

First parechovirus reported case in Saudi Arabia in hospitalized immunocompromised adult patient

Human parechovirus, a member of the Picornaviridae family (PeVs), can lead to severe infections, including severe meningitis, meningoencephalitis, and sepsis-like syndrome. We report a case of human parechovirus-related encephalitis in a 52-year-old woman diagnosed with glioblastoma multiforme. She underwent surgical resection in June 2022. Unfortunately, her disease recurred, and she underwent a second resection in August 2022, followed by radiation therapy and Temozolomide therapy. She presented to the hospital with acute confusion followed by seizures, necessitating intubation for airway support. A cerebrospinal fluid (CSF) sample was obtained and processed using the Biofire FilmArray, which reported the detection of HSV-1. Despite being on Acyclovir, the patient did not show signs of improvement. Consequently, a second CSF sample was obtained and sent for next-generation sequencing (NGS), which returned a positive result for Parechovirus. In this presented case, the patient exhibited symptoms of an unknown infectious cause. The utilization of NGS and metagenomic analysis helped identify Parechovirus as the primary pathogen present, in addition to previously identified HSV. This comprehensive approach facilitated a thorough assessment of the underlying infection and guided targeted treatment. In conclusion, the application of NGS techniques and metagenomic analysis proved instrumental in identifying the root cause of the infection.

Global Meta-analysis of Urine Microbiome: Colonization of Polycyclic Aromatic Hydrocarbon–degrading Bacteria Among Bladder Cancer Patients

BackgroundThe application of next-generation sequencing techniques has enabled characterization of urinary tract microbiome. Although many studies have demonstrated associations between the human microbiome and bladder cancer (BC), these have not always reported consistent results, thereby necessitating cross-study comparisons. Thus, the fundamental questions remain how we can utilize this knowledge. ObjectiveThe aim of our study was to examine the disease-associated changes in urine microbiome communities globally utilizing a machine learning algorithm. Design, setting, and participantsRaw FASTQ files were downloaded for the three published studies in urinary microbiome in BC patients, in addition to our own prospectively collected cohort. Outcome measurements and statistical analysisDemultiplexing and classification were performed using the QIIME 2020.8 platform. De novo operational taxonomic units were clustered using the uCLUST algorithm and defined by 97% sequence similarity and classified at the phylum level against the Silva RNA sequence database. The metadata available from the three studies included were used to evaluate the differential abundance between BC patients and controls via a random-effect meta-analysis using the metagen R function. A machine learning analysis was performed using the SIAMCAT R package. Results and limitationsOur study includes 129 BC urine and 60 healthy control samples across four different countries. We identified a total of 97/548 genera to be differentially abundant in the BC urine microbiome compared with that of healthy patients. Overall, while the differences in diversity metrics were clustered around the country of origin (Kruskal-Wallis, p < 0.001), collection methodology was a driver of microbiome composition. When assessing dataset from China, Hungary, and Croatia, data demonstrated no discrimination capacity to distinguish between BC patients and healthy adults (area under the curve [AUC] 0.577). However, inclusion of samples with catheterized urine improved the diagnostic accuracy of prediction for BC to AUC 0.995, with precision-recall AUC = 0.994. Through elimination of contaminants associated with the collection methodology among all cohorts, our study identified increased abundance of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria Sphingomonas, Acinetobacter, Micrococcus, Pseudomonas, and Ralstonia to be consistently present in BC patients. ConclusionsThe microbiota of the BC population may be a reflection of PAH exposure from smoking, environmental pollutants, and ingestion. Presence of PAHs in the urine of BC patients may allow for a unique metabolic niche and provide necessary metabolic resources where other bacteria are not able to flourish. Furthermore, we found that while compositional differences are associated with geography more than with disease, many are driven by the collection methodology. Patient summaryThe goal of our study was to compare the urine microbiome of bladder cancer patients with that of healthy controls and evaluate any potential bacteria that may be more likely to be found in patients with bladder cancer. Our study is unique as it evaluates this across multiple countries, to find a common pattern. After we removed some of the contamination, we were able to localize several key bacteria that are more likely to be found in the urine of bladder cancer patients. These bacteria all share their ability to break down tobacco carcinogens.

Next Generation Sequencing for the Analysis of Parvovirus B19 Genomic Diversity.

Parvovirus B19 (B19V) is a ssDNA human virus, responsible for an ample range of clinical manifestations. Sequencing of B19V DNA from clinical samples is frequently reported in the literature to assign genotype (genotypes 1-3) and for finer molecular epidemiological tracing. The increasing availability of Next Generation Sequencing (NGS) with its depth of coverage potentially yields information on intrinsic sequence heterogeneity; however, integration of this information in analysis of sequence variation is not routinely obtained. The present work investigated genomic sequence heterogeneity within and between B19V isolates by application of NGS techniques, and by the development of a novel dedicated bioinformatic tool and analysis pipeline, yielding information on two newly defined parameters. The first, α-diversity, is a measure of the amount and distribution of position-specific, normalised Shannon Entropy, as a measure of intra-sample sequence heterogeneity. The second, σ-diversity, is a measure of the amount of inter-sample sequence heterogeneity, also incorporating information on α-diversity. Based on these indexes, further cluster analysis can be performed. A set of 24 high-titre viraemic samples was investigated. Of these, 23 samples were genotype 1 and one sample was genotype 2. Genotype 1 isolates showed low α-diversity values, with only a few samples showing distinct position-specific polymorphisms; a few genetically related clusters emerged when analysing inter-sample distances, correlated to the year of isolation; the single genotype 2 isolate showed the highest α-diversity, even if not presenting polymorphisms, and was an evident outlier when analysing inter-sample distance. In conclusion, NGS analysis and the bioinformatic tool and pipeline developed and used in the present work can be considered effective tools for investigating sequence diversity, an observable parameter that can be incorporated into the quasispecies theory framework to yield a better insight into viral evolution dynamics.

A review of migraine genetics: gathering genomic and transcriptomic factors.

Migraine is a common and complex neurologic disorder that affects approximately 15-18% of the general population. Although the cause of migraine is unknown, some genetic studies have focused on unravelling rare and common variants underlying the pathophysiological mechanisms of this disorder. This review covers the advances in the last decade on migraine genetics, throughout the history of genetic methodologies used, including recent application of next-generation sequencing techniques. A thorough review of the literature interweaves the genomic and transcriptomic factors that will allow a better understanding of the mechanisms underlying migraine pathophysiology, concluding with the clinical utility landscape of genetic information and future consideration to creating a new frontier toward advancing the field of personalized medicine.

Perspectives on Precision Medicine in Chronic Lymphocytic Leukemia: Targeting Recurrent Mutations-NOTCH1, SF3B1, MYD88, BIRC3.

Chronic lymphocytic leukemia (CLL) is highly heterogeneous, with extremely variable clinical course. The clinical heterogeneity of CLL reflects differences in the biology of the disease, including chromosomal alterations, specific immunophenotypic patterns and serum markers. The application of next-generation sequencing techniques has demonstrated the high genetic and epigenetic heterogeneity in CLL. The novel mutations could be pharmacologically targeted for individualized approach in some of the CLL patients. Potential neurogenic locus notch homolog protein 1 (NOTCH1) signalling targeting mechanisms in CLL include secretase inhibitors and specific antibodies to block NOTCH ligand/receptor interactions. In vitro studies characterizing the effect of the splicing inhibitors resulted in increased apoptosis of CLL cells regardless of splicing factor 3B subunit 1 (SF3B1) status. Several therapeutic strategies have been also proposed to directly or indirectly inhibit the toll-like receptor/myeloid differentiation primary response gene 88 (TLR/MyD88) pathway. Another potential approach is targeting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and inhibition of this prosurvival pathway. Newly discovered mutations and their signalling pathways play key roles in the course of the disease. This opens new opportunities in the management and treatment of CLL.

Understanding of Adventitious Root Formation: What Can We Learn From Comparative Genetics?

Adventitious root (AR) formation is a complex developmental process controlled by a plethora of endogenous and environmental factors. Based on fossil evidence and genomic phylogeny, AR formation might be considered the default state of plant roots, which likely evolved independently several times. The application of next-generation sequencing techniques and bioinformatics analyses to non-model plants provide novel approaches to identify genes putatively involved in AR formation in multiple species. Recent results uncovered that the regulation of shoot-borne AR formation in monocots is an adaptive response to nutrient and water deficiency that enhances topsoil foraging and improves plant performance. A hierarchy of transcription factors required for AR initiation has been identified from genetic studies, and recent results highlighted the key involvement of additional regulation through microRNAs. Here, we discuss our current understanding of AR formation in response to specific environmental stresses, such as nutrient deficiency, drought or waterlogging, aimed at providing evidence for the integration of the hormone crosstalk required for the activation of root competent cells within adult tissues from which the ARs develop.

The Involvement of Phytophthora Root Rot and Drought Stress in Holm Oak Decline: from Ecophysiology to Microbiome Influence

Holm oak is a relevant species, both for its distribution and ecological importance. Among the risks looming over this species, oak decline—influenced by extreme climatic events, and alien-invasive species—is considered the main factor causing the loss of holm oak in Mediterranean open woodlands. The aim of this review is to identify and summarize the effects of drought and pathogen root rot, focusing on tree physiology, and the relationship between the stressors (biotic and abiotic) and the tree response. Symptoms of root rot are often associated with drought. However, it has been shown the presence of a differential response to root rot and severe drought is related with general defence mechanisms triggered by the plant. Soil microbiota has also been shown to be a key factor influencing health status and soil pathogen abundance. The application of next-generation sequencing techniques to forest pathology allows us to study complex relationships between soil, plant and microorganisms. Tolerance of holm oak against Phytophthora cinnamomi root rot is related to specific hydric and photosynthetic mechanisms that differ from those associated with drought. This response involves changes in the metabolism of the photosynthetic organs of the plant which can be linked with changes in functional traits. Studies of the soil microbiome have identified several pathogens, apart from P. cinnamomi, involved in holm oak decline, and the relevance of key fungal species in the management of this syndrome. In this regard, the presence of beneficial microorganisms such as Trichoderma spp. or ectomycorrhizae influences the physiological status of trees affected by root rot.

Clinical, Histopathological, and Molecular Diagnostics in Lethal Lung Developmental Disorders.

Lethal lung developmental disorders are a rare but important group of pediatric diffuse lung diseases presenting with neonatal respiratory failure. On the basis of histopathological appearance at lung biopsy or autopsy, they have been termed: alveolar capillary dysplasia with misalignment of the pulmonary veins, acinar dysplasia, congenital alveolar dysplasia, and other unspecified primary pulmonary hypoplasias. However, the histopathological continuum in these lethal developmental disorders has made accurate diagnosis challenging, which has implications for recurrence risk. Over the past decade, genetic studies in infants with alveolar capillary dysplasia with misalignment of the pulmonary veins have revealed the causative role of the dosage-sensitive FOXF1 gene and its noncoding regulatory variants in the distant lung-specific enhancer at chromosome 16q24.1. In contrast, the molecular bases of acinar dysplasia and congenital alveolar dysplasia have remained poorly understood. Most recently, disruption of the TBX4-FGF10-FGFR2 epithelial-mesenchymal signaling pathway has been reported in patients with these lethal pulmonary dysplasias. Application of next-generation sequencing techniques, including exome sequencing and whole-genome sequencing, has demonstrated their complex compound inheritance. These data indicate that noncoding regulatory elements play a critical role in lung development in humans. We propose that for more precise lethal lung developmental disorder diagnosis, a diagnostic pathway including whole-genome sequencing should be implemented.

Transcriptome Sequencing of Different Avocado Ecotypes: de novo Transcriptome Assembly, Annotation, Identification and Validation of EST-SSR Markers

Avocado (Persea americana Mill.) could be considered as an important tropical and subtropical woody oil crop with high economic and nutritional value. Despite the importance of this species, genomic information is currently unavailable for avocado and closely related congeners. In this study, we generated more than 216 million clean reads from different avocado ecotypes using Illumina HiSeq high-throughput sequencing technology. The high-quality reads were assembled into 154,310 unigenes with an average length of 922 bp. A total of 55,558 simple sequence repeat (SSR) loci detected among the 43,270 SSR-containing unigene sequences were used to develop 74,580 expressed sequence tag (EST)-SSR markers. From these markers, a subset of 100 EST-SSR markers was randomly chosen to identify polymorphic EST-SSR markers in 28 avocado accessions. Sixteen EST-SSR markers with moderate to high polymorphism levels were detected, with polymorphism information contents ranging from 0.33 to 0.84 and averaging 0.63. These 16 polymorphic EST-SSRs could clearly and effectively distinguish the 28 avocado accessions. In summary, our study is the first presentation of transcriptome data of different avocado ecotypes and comprehensive study on the development and analysis of a set of EST-SSR markers in avocado. The application of next-generation sequencing techniques for SSR development is a potentially powerful tool for genetic studies.

Application of next-generation sequencing technique in genetic analysis of spontaneous abortion

Objective To investigate the value of next-generation sequencing (NGS) technique for genetic analysis of spontaneous abortion. Methods From January to June 2017, 154 patients who visited the First Affiliated Hospital of Zhengzhou University for spontaneous abortion were enrolled. All abortion tissue samples were analyzed by both NGS combined with short tandem repeat (STR) and single nucleotide polymorphism array (SNP-array). Results of the two methods were compared by Chi-square or Fisher's exact test. Results (1) Chromosomal abnormalities were detected in 109 of the 154 cases (70.7%), including 52 (47.7%) of numerical chromosomal abnormalities, 49 (45.0%) of structural chromosomal abnormalities, six (5.5%) of mosaicism, and two (1.8%) of uniparental disomy (UPD). In those 52 cases of numerical chromosome abnormalities, there were 45 of chromosome aneuploidy and seven of polyploidy. The top three numerical chromosomal abnormalities were 45,X (27.0%, 14/52), trisomy 22 (9.6%, 5/52) and trisomy 16 (7.7%, 4/52). Forty-nine structural abnormality cases carried 67 copy number variations (CNV), including 13 pathogenic CNV (pCNV, 19.4%), 24 variants of unknown clinical significance (35.8%) and 30 benign CNV (44.8%). In those 13 pCNVs, two were responsible for microdeletion and microduplication syndromes. (2) SNP-array was successful in 152 cases, but failed in two (1.3%) due to genomic DNA <200 ng. However, NGS technology was successful in all 154 cases and identified chromosomal abnormalities in the two cases that SNP-array had failed. No statistically significant difference was shown in the detection rate of chromosomal abnormalities between SNP-array and NGS technology [70.4% (107/152) vs 67.5% (104/154), χ2=0.293, P=0.588]. (3) No significant difference in the detection of chromosome aneuploidy (six cases in each group, 3.9% vs 3.9%) and mosaicism (45 cases in each group, 29.2% vs 29.6%) was found between NGS technology and SNP-array. Three cases of polyploidy (69, XXX) and two of UPD were identified by SNP-array, but not by NGS. When combined with STR, NGS was able to detect all three cases of polyploidy (69, XXX). (4) Forty-seven structural abnormality cases detected by SNP-array carried 53 CNVs, and 49 detected by NGS carried 67 CNVs. (5) NGS detected ten, three and one more CNVs than SNP-array did when the genome lengths were 100-<500, 500-<1 000 and ≥1 000 kb, respectively. Conclusions NGS can be used to detect chromosomal aneuploidy and mosaicism that can be identified by SNP-array with fewer limitations on total amount of genome. Moreover, CNVs that fail to be identified by SNP-array can also be detected by NGS. When combined with STR, NGS can effectively detect chromosomal polyploidy. Therefore, NGS could be a potential genetic analysis method for spontaneous abortion and of importance for genetic counseling. Key words: Abortion, spontaneous; High-throughput nucleotide sequencing; Chromosome aberrations; Polymorphism, single nucleotide

Mycorrhizal fungi affect orchid distribution and population dynamics.

Symbioses are ubiquitous in nature and influence individual plants and populations. Orchids have life history stages that depend fully or partially on fungi for carbon and other essential resources. As a result, orchid populations depend on the distribution of orchid mycorrhizal fungi (OMFs). We focused on evidence that local-scale distribution and population dynamics of orchids can be limited by the patchy distribution and abundance of OMFs, after an update of an earlier review confirmed that orchids are rarely limited by OMF distribution at geographic scales. Recent evidence points to a relationship between OMF abundance and orchid density and dormancy, which results in apparent density differences. Orchids were more abundant, less likely to enter dormancy, and more likely to re-emerge when OMF were abundant. We highlight the need for additional studies on OMF quantity, more emphasis on tropical species, and development and application of next-generation sequencing techniques to quantify OMF abundance in substrates and determine their function in association with orchids. Research is also needed to distinguish between OMFs and endophytic fungi and to determine the function of nonmycorrhizal endophytes in orchid roots. These studies will be especially important if we are to link orchids and OMFs in efforts to inform conservation.

Transcriptomic analysis of developing embryos of apricot (Prunus armeniaca L.)

Apricot (Prunus armeniaca L.) is an important, nutritionally valuable agricultural crop. A scarcity of transcriptomic and genomic data hinders progress toward understanding the molecular events of apricot embryogenesis, which is the primary determinant of fruit yield and kernel quality. In this study, three cDNA libraries were sequenced using an Illumina/Solexa platform. We obtained 35,928,496, 40,656,940, and 35,970,214 clean reads from endosperm formation (LT-A), embryo development (LT-B), and mature embryo (LT-C) cDNA libraries, respectively. De novo assembly of cDNA sequence data generated 35,614 unigenes with an average length of 973 bp. A total of 29,971 unigenes were matched in Nr, Nt, Swiss-Prot, KEGG, GO, and COG databases. The top matching species in the Nr database was P. persica (88.3% of matched Nr database accessions). A total of 8,327 differentially expressed genes (DEGs) were detected between LT-A and LT-B, of which 3,663 were upregulated and 4,664 were downregulated. Between LT-B and LT-C, 12,673 DEGs were detected, while 13,892 DEGs were uncovered between LT-A and LT-C. This work is the first reported application of next-generation sequencing techniques for transcriptome analysis of apricot embryo development. Besides providing valuable information on apricot embryo development, the comprehensive set of transcript sequences generated in this study may serve as additional molecular resources for the development of apricot functional genomics.

Genomic alterations underlying immune privilege in malignant lymphomas.

Malignant lymphomas represent a remarkably heterogeneous group of cancers with respect to their oncogenome, phenotype and clinical presentation. Lymphoma cells benefit from limited immune surveillance and have developed various mechanisms to alter antitumor immune responses. This article summarizes our current knowledge about genomic alterations underlying acquired immune privilege in lymphoid cancers. The implementation and broad application of next-generation sequencing techniques have significantly expanded our knowledge about genetic alterations and perturbed cellular pathways underlying lymphomagenesis. Based on key discoveries in the past decade, the purview of subsequent studies expanded beyond the biology of the lymphoma cells to include the pathogenic contribution of immune cells, stromal components and associated crosstalk between malignant and nonmalignant cells in the tumor microenvironment. A number of genetic mechanisms have been described that elucidate how lymphoma cells are selected for evading immune recognition and reprogramming immune responses. These prominently include structural genomic changes of the CIITA and programmed death ligand (CD274/PDCD1LG2) loci, alterations affecting antigen presentation and mutations in JAK-STAT and NFκB signaling pathways. Further investigations will foster our understanding about synergy of immune escape mechanisms, and lay the foundation for the development of predictive biomarkers in the context of conceptually novel therapies targeting microenvironment-related biology, such as immunological checkpoint inhibition.

Reflections on the US FDA's Warning on Direct-to-Consumer Genetic Testing.

In November 2013, the US Food and Drug Administration (FDA) sent a warning letter to 23andMe, Inc. and ordered the company to discontinue marketing of the 23andMe Personal Genome Service (PGS) until it receives FDA marketing authorization for the device. The FDA considers the PGS as an unclassified medical device, which requires premarket approval or de novo classification. Opponents of the FDA's action expressed their concerns, saying that the FDA is overcautious and paternalistic, which violates consumers' rights and might stifle the consumer genomics field itself, and insisted that the agency should not restrict direct-to-consumer (DTC) genomic testing without empirical evidence of harm. Proponents support the agency's action as protection of consumers from potentially invalid and almost useless information. This action was also significant, since it reflected the FDA's attitude towards medical application of next-generation sequencing techniques. In this review, we followed up on the FDA-23andMe incident and evaluated the problems and prospects for DTC genetic testing.

Tackling Skeletal Muscle Cells Epigenome in the Next-Generation Sequencing Era

Recent advances in high-throughput technologies have transformed methodologies employed to study cell-specific epigenomes and the approaches to investigate complex cellular phenotypes. Application of next-generation sequencing technology in the skeletal muscle differentiation field is rapidly extending our knowledge on how chromatin modifications, transcription factors and chromatin regulators orchestrate gene expression pathways guiding myogenesis. Here, we review recent biological insights gained by the application of next-generation sequencing techniques to decode the epigenetic profile and gene regulatory networks underlying skeletal muscle differentiation.