Predicting Outcomes of Preterm Neonates Post Intraventricular Hemorrhage.

Intraventricular hemorrhage (IVH) in preterm neonates presents a high risk for developing posthemorrhagic ventricular dilatation (PHVD), a severe complication that can impact survival and long-term outcomes. Early detection of PHVD before clinical onset is crucial for optimizing therapeutic interventions and providing accurate parental counseling. This study explores the potential of explainable machine learning models based on targeted liquid biopsy proteomics data to predict outcomes in preterm neonates with IVH. In recent years, research has focused on leveraging advanced proteomic technologies and machine learning to improve prediction of neonatal complications, particularly in relation to neurological outcomes. Machine learning (ML) approaches, combined with proteomics, offer a powerful tool to identify biomarkers and predict patient-specific risks. However, challenges remain in integrating large-scale, multiomic datasets and translating these findings into actionable clinical tools. Identifying reliable, disease-specific biomarkers and developing explainable ML models that clinicians can trust and understand are key barriers to widespread clinical adoption. In this prospective longitudinal cohort study, we analyzed 1109 liquid biopsy samples from 99 preterm neonates with IVH, collected at up to six timepoints over 13 years. Various explainable ML techniques-including statistical, regularization, deep learning, decision trees, and Bayesian methods-were employed to predict PHVD development and survival and to discover disease-specific protein biomarkers. Targeted proteomic analyses were conducted using serum and urine samples through a proximity extension assay capable of detecting low-concentration proteins in complex biofluids. The study identified 41 significant independent protein markers in the 1600 calculated ML models that surpassed our rigorous threshold (AUC-ROC of ≥0.7, sensitivity ≥ 0.6, and selectivity ≥ 0.6), alongside gestational age at birth, as predictive of PHVD development and survival. Both known biomarkers, such as neurofilament light chain (NEFL), and novel biomarkers were revealed. These findings underscore the potential of targeted proteomics combined with ML to enhance clinical decision-making and parental counseling, though further validation is required before clinical implementation.

Neurodevelopmental outcome in preterm infants with intraventricular hemorrhages: the potential of quantitative brainstem MRI.

OBJECTIVES: This retrospective study aimed to identify quantitative magnetic resonance imaging markers in the brainstem of preterm neonates with intraventricular hemorrhages. It delves into the intricate associations between quantitative brainstem magnetic resonance imaging metrics and neurodevelopmental outcomes in preterm infants with intraventricular hemorrhage, aiming to elucidate potential relationships and their clinical implications. MATERIALS AND METHODS: Neuroimaging was performed on preterm neonates with intraventricular hemorrhage using a multi-dynamic multi-echo sequence to determine T1 relaxation time, T2 relaxation time, and proton density in specific brainstem regions. Neonatal outcome scores were collected using the Bayley Scales of Infant and Toddler Development. Statistical analysis aimed to explore potential correlations between magnetic resonance imaging metrics and neurodevelopmental outcomes. RESULTS: Sixty preterm neonates (mean gestational age at birth 26.26 ± 2.69 wk; n = 24 [40%] females) were included. The T2 relaxation time of the midbrain exhibited significant positive correlations with cognitive (r = 0.538, P < 0.0001, Pearson's correlation), motor (r = 0.530, P < 0.0001), and language (r = 0.449, P = 0.0008) composite scores at 1 yr of age. CONCLUSION: Quantitative magnetic resonance imaging can provide valuable insights into neurodevelopmental outcomes after intraventricular hemorrhage, potentially aiding in identifying at-risk neonates. Multi-dynamic multi-echo sequence sequences hold promise as an adjunct to conventional sequences, enhancing the sensitivity of neonatal magnetic resonance neuroimaging and supporting clinical decision-making for these vulnerable patients.

Patients with Systemic Juvenile Idiopathic Arthritis (SJIA) Show Differences in Autoantibody Signatures Based on Disease Activity.

Systemic juvenile idiopathic arthritis (SJIA) is a severe rheumatic disease in children. It is a subgroup of juvenile idiopathic arthritis (JIA; MIM #604302), which is the most common rheumatic disease in children. The diagnosis of SJIA often comes with a significant delay, and the classification between autoinflammatory and autoimmune disease is still discussed. In this study, we analyzed the immunological responses of patients with SJIA, using human proteome arrays presenting immobilized recombinantly expressed human proteins, to analyze the involvement of autoantibodies in SJIA. Results from group comparisons show several differentially reactive antigens involved in inflammatory processes. Intriguingly, many of the identified antigens had a high reactivity against proteins involved in the NF-κB pathway, and it is also notable that many of the detected DIRAGs are described as dysregulated in rheumatoid arthritis. Our data highlight novel proteins and pathways potentially dysregulated in SJIA and offer a unique approach to unraveling the underlying disease pathogenesis in this chronic arthropathy.

Accessing Antibody Reactivities in Serum or Plasma to (Auto-)antigens Using Multiplexed Bead-Based Protein Immunoassays.

Antibody (AB) testing or serotesting for reactive ABs against antigenic proteins is broadly used. Parallel examination of many antigens is of high interest to identify autoantibodies (AAB) or differential antigenic reactivities in many biological settings like allergy and infectious autoimmune, cancerous, or systemic disease. The resulting AAB profiles can be used for diagnosis, prognosis, and monitoring of such conditions. Protein microarrays have been used for AB profiling over the past decade but show some significant limitations which make them unsuitable for clinical applications. Alternative multiplexing platforms such as bead arrays were shown to provide a versatile tool for the confirmation and efficient analysis of high numbers of biological samples. Luminex' bead-based xMAP technology combines advantages such as multiplexing and lower demand for sample volume and at the same time overcomes the challenges of microarrays. It works faster, shows better antigen stability, is more reproducible, and allows the analysis of up to 500 analytes in one sample well. In this chapter we introduce our established workflow for the use of the xMAP technology for AB profiling including an overview of the method principle and protocols for the covalent immobilization of proteins to the MagPlex beads, confirmation of protein coupling, the execution of a multiplexed bead-based protein immunoassay, and subsequent data handling.

Multiplexed Bead-Based Peptide Immunoassays for the Detection of Antibody Reactivities.

Antigenic peptides are commonly used in serological test settings such as enzyme-linked immunosorbent assays (ELISA) to determine reactive antibodies (ABs) from serum or plasma samples. The use of synthetic peptides provides advantages like lower production effort and easier incorporation of specific chemical modifications compared to full-length antigenic proteins. Multiplexed antibody (AB) profiling methods such as microarray technologies enable the simultaneous identification of multiple novel biomarkers for the use in early disease diagnostics, vaccine development, or monitoring of immune responses. Despite various benefits they still show major limitations which can be overcome with bead-based assay technologies like the multi-analyte profiling (xMAP) technology developed by Luminex. In this chapter we introduce our established workflow for AB profiling with a multiplexed bead-based peptide immunoassay. The workflow is based on copper-catalyzed click chemistry to immobilize designed synthetic peptides onto uniquely color-coded paramagnetic beads in an orientation-specific manner. The individual peptide-coupled beads can be distinguished by their unique emission spectra during readout in the xMAP instrument and therefore allow testing of up to 500 different antigenic peptides in one multiplexed reaction. The multistep process described in this chapter is divided into separate sections for peptide design, coupling of functionalized peptides to MagPlex beads via click chemistry, confirmation of successful peptide immobilization, processing of serum or plasma samples, or preferably purified IgG thereof, with the multiplexed bead-based peptide immunoassay and subsequent data export and analysis.

Antibody Profiling and In Silico Functional Analysis of Differentially Reactive Antibody Signatures of Glioblastomas and Meningiomas.

Studies on tumor-associated antigens in brain tumors are sparse. There is scope for enhancing our understanding of molecular pathology, in order to improve on existing forms, and discover new forms, of treatment, which could be particularly relevant to immuno-oncological strategies. To elucidate immunological differences, and to provide another level of biological information, we performed antibody profiling, based on a high-density protein array (containing 8173 human transcripts), using IgG isolated from the sera of n = 12 preoperative and n = 16 postoperative glioblastomas, n = 26 preoperative and n = 29 postoperative meningiomas, and n = 27 healthy, cancer-free controls. Differentially reactive antigens were compared to gene expression data from an alternate public GBM data set from OncoDB, and were analyzed using the Reactome pathway browser. Protein array analysis identified approximately 350-800 differentially reactive antigens, and revealed different antigen profiles in the glioblastomas and meningiomas, with approximately 20-30%-similar and 10-15%-similar antigens in preoperative and postoperative sera, respectively. Seroreactivity did not correlate with OncoDB-derived gene expression. Antigens in the preoperative glioblastoma sera were enriched for signaling pathways, such as signaling by Rho-GTPases, COPI-mediated anterograde transport and vesicle-mediated transport, while the infectious disease, SRP-dependent membrane targeting cotranslational proteins were enriched in the meningiomas. The pre-vs. postoperative seroreactivity in the glioblastomas was enriched for antigens, e.g., platelet degranulation and metabolism of lipid pathways; in the meningiomas, the antigens were enriched in infectious diseases, metabolism of amino acids and derivatives, and cell cycle. Antibody profiling in both tumor entities elucidated several hundred antigens and characteristic signaling pathways that may provide new insights into molecular pathology and may be of interest for the development of new treatment strategies.

Targeting epigenetic features in clear cell sarcomas based on patient-derived cell lines.

BACKGROUND: Clear cell sarcomas (CCSs) are translocated aggressive malignancies, most commonly affecting young adults with a high incidence of metastases and a poor prognosis. Research into the disease is more feasible when adequate models are available. By establishing CCS cell lines from a primary and metastatic lesion and isolating healthy fibroblasts from the same patient, the in vivo process is accurately reflected and aspects of clinical multistep carcinogenesis recapitulated. METHODS: Isolated tumor cells and normal healthy skin fibroblasts from the same patient were compared in terms of growth behavior and morphological characteristics using light and electron microscopy. Tumorigenicity potential was determined by soft agar colony formation assay and in vivo xenograft applications. While genetic differences between the two lineages were examined by copy number alternation profiles, nuclear magnetic resonance spectroscopy determined arginine methylation as epigenetic features. Potential anti-tumor effects of a protein arginine N-methyltransferase type I (PRMT1) inhibitor were elicited in 2D and 3D cell culture experiments using cell viability and apoptosis assays. Statistical significance was calculated by one-way ANOVA and unpaired t-test. RESULTS: The two established CCS cell lines named MUG Lucifer prim and MUG Lucifer met showed differences in morphology, genetic and epigenetic data, reflecting the respective original tissue. The detailed cell line characterization especially in regards to the epigenetic domain allows investigation of new innovative therapies. Based on the epigenetic data, a PRMT1 inhibitor was used to demonstrate the targeted antitumor effect; normal tissue cells isolated and immortalized from the same patient were not affected with the IC50 used. CONCLUSIONS: MUG Lucifer prim, MUG Lucifer met and isolated and immortalized fibroblasts from the same patient represent an ideal in vitro model to explore the biology of CCS. Based on this cell culture model, novel therapies could be tested in the form of PRMT1 inhibitors, which drive tumor cells into apoptosis, but show no effect on fibroblasts, further supporting their potential as promising treatment options in the combat against CCS. The data substantiate the importance of tailored therapies in the advanced metastatic stage of CCS.

Functional Analysis of Autoantibody Signatures in Rheumatoid Arthritis.

For the identification of antigenic protein biomarkers for rheumatoid arthritis (RA), we conducted IgG profiling on high density protein microarrays. Plasma IgG of 96 human samples (healthy controls, osteoarthritis, seropositive and seronegative RA, n = 24 each) and time-series plasma of a pristane-induced arthritis (PIA) rat model (n = 24 total) were probed on AIT's 16k protein microarray. To investigate the analogy of underlying disease pathways, differential reactivity analysis was conducted. A total of n = 602 differentially reactive antigens (DIRAGs) at a significance cutoff of p < 0.05 were identified between seropositive and seronegative RA for the human samples. Correlation with the clinical disease activity index revealed an inverse correlation of antibodies against self-proteins found in pathways relevant for antigen presentation and immune regulation. The PIA model showed n = 1291 significant DIRAGs within acute disease. Significant DIRAGs for (I) seropositive, (II) seronegative and (III) PIA were subjected to the Reactome pathway browser which also revealed pathways relevant for antigen presentation and immune regulation; of these, seven overlapping pathways had high significance. We therefore conclude that the PIA model reflects the biological similarities of the disease pathogenesis. Our data show that protein array analysis can elucidate biological differences and pathways relevant in disease as well be a useful additional layer of omics information.

Designed SARS-CoV-2 receptor binding domain variants form stable monomers.

The receptor binding domain (RBD) of the SARS-CoV-2 spike (S)-protein is a prime target of virus-neutralizing antibodies present in convalescent sera of COVID-19 patients and thus is considered a key antigen for immunosurveillance studies and vaccine development. Although recombinant expression of RBD has been achieved in several eukaryotic systems, mammalian cells have proven particularly useful. The authors aimed to optimize RBD produced in HEK293-6E cells towards a stable homogeneous preparation and addressed its O-glycosylation as well as the unpaired cysteine residue 538 in the widely used RBD (319-541) sequence. The authors found that an intact O-glycosylation site at T323 is highly relevant for the expression and maintenance of RBD as a monomer. Furthermore, it was shown that deletion or substitution of the unpaired cysteine residue C538 reduces the intrinsic propensity of RBD to form oligomeric aggregates, concomitant with an increased yield of the monomeric form of the protein. Bead-based and enzyme-linked immunosorbent assays utilizing these optimized RBD variants displayed excellent performance with respect to the specific detection of even low levels of SARS-CoV-2 antibodies in convalescent sera. Hence, these RBD variants could be instrumental for the further development of serological SARS-CoV-2 tests and inform the design of RBD-based vaccine candidates.

Circulating serum microRNAs including senescent miR-31-5p are associated with incident fragility fractures in older postmenopausal women with type 2 diabetes mellitus.

Fragility fractures are an important hallmark of aging and an increasingly recognized complication of Type 2 diabetes (T2D). T2D individuals have been found to exhibit an increased fracture risk despite elevated bone mineral density (BMD) by dual x-ray absorptiometry (DXA). However, BMD and FRAX-scores tend to underestimate fracture risk in T2D. New, reliable biomarkers are therefore needed. MicroRNAs (miRNAs) are secreted into the circulation from cells of various tissues proportional to local disease severity. Serum miRNA-classifiers were recently found to discriminate T2D women with and without prevalent fragility fractures with high specificity and sensitivity (AUC > 0.90). However, the association of circulating miRNAs with incident fractures in T2D has not been examined yet. In 168 T2D postmenopausal women in the AGES-Reykjavik cohort, miRNAs were extracted from baseline serum and a panel of 10 circulating miRNAs known to be involved in diabetic bone disease and aging was quantified by qPCR and Ct-values extracted. Unadjusted and adjusted Cox proportional hazard models assessed the associations between serum miRNAs and incident fragility fracture. Additionally, Receiver operating curve (ROC) analyses were performed. Of the included 168 T2D postmenopausal women who were on average 77.2 ±â€¯5.6 years old, 70 experienced at least one incident fragility fracture during the mean follow-up of 5.8 ±â€¯2.7 years. We found that 3 serum miRNAs were significantly associated with incident diabetic fragility fracture: while low expression of miR-19b-1-5p was associated with significantly lower risk of incident fragility fracture (HR 0.84 (95% CI: 0.71-0.99, p = 0.0323)), low expression of miR-203a and miR-31-5p was each significantly associated with a higher risk of incident fragility fracture per unit increase in Ct-value (miR-203a: HR 1.29 (95% CI: 1.12-1.49), p = 0.0004, miR-31-5p HR 1.27 (95% CI: 1.06-1.52), p = 0.009). Hazard ratios of the latter two miRNAs remained significant after adjustments for age, body mass index (BMI), areal bone mineral density (aBMD), clinical FRAX or FRAXaBMD. Women with miR-203a and miR-31-5p serum levels in the lowest expression quartiles exhibited a 2.4-3.4-fold larger fracture risk than women with miR-31-5p and miR-203a serum expressions in the highest expression quartile (0.002 ≤ p ≤ 0.039). Women with both miR-203a and miR-31-5p serum levels below the median had a significantly increased fracture risk (Unadjusted HR 3.26 (95% CI: 1.57-6.78, p = 0.001) compared to those with both expression levels above the median, stable to adjustments. We next built a diabetic fragility signature consisting of the 3 miRNAs that showed the largest associations with incident fracture (miR-203a, miR-31-5p, miR-19b-1-5p). This 3-miRNA signature showed with an AUC of 0.722 comparable diagnostic accuracy in identifying incident fractures to any of the clinical parameters such as aBMD, Clinical FRAX or FRAXaBMD alone. When the 3 miRNAs were combined with aBMD, this combined 4-feature signature performed with an AUC of 0.756 (95% CI: 0.680, 0.823) significantly better than aBMD alone (AUC 0.666, 95% CI: 0.585, 0.741) (p = 0.009). Our data indicate that specific serum microRNAs including senescent miR-31-5p are associated with incident fragility fracture in older diabetic women and can significantly improve fracture risk prediction in diabetics when combined with aBMD measurements of the femoral neck.

Impact of Specific N-Glycan Modifications on the Use of Plant-Produced SARS-CoV-2 Antigens in Serological Assays.

The receptor binding domain (RBD) of the SARS-CoV-2 spike protein plays a key role in the virus-host cell interaction, and viral infection. The RBD is a major target for neutralizing antibodies, whilst recombinant RBD is commonly used as an antigen in serological assays. Such assays are essential tools to gain control over the pandemic and detect the extent and durability of an immune response in infected or vaccinated populations. Transient expression in plants can contribute to the fast production of viral antigens, which are required by industry in high amounts. Whilst plant-produced RBDs are glycosylated, N-glycan modifications in plants differ from humans. This can give rise to the formation of carbohydrate epitopes that can be recognized by anti-carbohydrate antibodies present in human sera. For the performance of serological tests using plant-produced recombinant viral antigens, such cross-reactive carbohydrate determinants (CCDs) could result in false positives. Here, we transiently expressed an RBD variant in wild-type and glycoengineered Nicotiana benthamiana leaves and characterized the impact of different plant-specific N-glycans on RBD reactivity in serological assays. While the overall performance of the different RBD glycoforms was comparable to each other and to a human cell line produced RBD, there was a higher tendency toward false positive results with sera containing allergy-related CCD-antibodies when an RBD carrying ß1,2-xylose and core α1,3-fucose was used. These rare events could be further minimized by pre-incubating sera from allergic individuals with a CCD-inhibitor. Thereby, false positive signals obtained from anti-CCD antibodies, could be reduced by 90%, on average.

N-Glycosylation of the SARS-CoV-2 Receptor Binding Domain Is Important for Functional Expression in Plants.

Nicotiana benthamiana is used worldwide as production host for recombinant proteins. Many recombinant proteins such as monoclonal antibodies, growth factors or viral antigens require posttranslational modifications like glycosylation for their function. Here, we transiently expressed different variants of the glycosylated receptor binding domain (RBD) from the SARS-CoV-2 spike protein in N. benthamiana. We characterized the impact of variations in RBD-length and posttranslational modifications on protein expression, yield and functionality. We found that a truncated RBD variant (RBD-215) consisting of amino acids Arg319-Leu533 can be efficiently expressed as a secreted soluble protein. Purified RBD-215 was mainly present as a monomer and showed binding to the conformation-dependent antibody CR3022, the cellular receptor angiotensin converting enzyme 2 (ACE2) and to antibodies present in convalescent sera. Expression of RBD-215 in glycoengineered ΔXT/FT plants resulted in the generation of complex N-glycans on both N-glycosylation sites. While site-directed mutagenesis showed that the N-glycans are important for proper RBD folding, differences in N-glycan processing had no effect on protein expression and function.

A comprehensive antigen production and characterisation study for easy-to-implement, specific and quantitative SARS-CoV-2 serotests.

BACKGROUND: Antibody tests are essential tools to investigate humoral immunity following SARS-CoV-2 infection or vaccination. While first-generation antibody tests have primarily provided qualitative results, accurate seroprevalence studies and tracking of antibody levels over time require highly specific, sensitive and quantitative test setups. METHODS: We have developed two quantitative, easy-to-implement SARS-CoV-2 antibody tests, based on the spike receptor binding domain and the nucleocapsid protein. Comprehensive evaluation of antigens from several biotechnological platforms enabled the identification of superior antigen designs for reliable serodiagnostic. Cut-off modelling based on unprecedented large and heterogeneous multicentric validation cohorts allowed us to define optimal thresholds for the tests' broad applications in different aspects of clinical use, such as seroprevalence studies and convalescent plasma donor qualification. FINDINGS: Both developed serotests individually performed similarly-well as fully-automated CE-marked test systems. Our described sensitivity-improved orthogonal test approach assures highest specificity (99.8%); thereby enabling robust serodiagnosis in low-prevalence settings with simple test formats. The inclusion of a calibrator permits accurate quantitative monitoring of antibody concentrations in samples collected at different time points during the acute and convalescent phase of COVID-19 and disclosed antibody level thresholds that correlate well with robust neutralization of authentic SARS-CoV-2 virus. INTERPRETATION: We demonstrate that antigen source and purity strongly impact serotest performance. Comprehensive biotechnology-assisted selection of antigens and in-depth characterisation of the assays allowed us to overcome limitations of simple ELISA-based antibody test formats based on chromometric reporters, to yield comparable assay performance as fully-automated platforms. FUNDING: WWTF, Project No. COV20-016; BOKU, LBI/LBG.

Expression Profiling Suggests Loss of Surface Integrity and Failure of Regenerative Repair as Major Driving Forces for Chronic Obstructive Pulmonary Disease Progression.

Chronic obstructive pulmonary disease (COPD) poses a major risk for public health, yet remarkably little is known about its detailed pathophysiology. Definition of COPD as nonreversible pulmonary obstruction revealing more about spatial orientation than about mechanisms of pathology may be a major reason for this. We conducted a controlled observational study allowing for simultaneous assessment of clinical and biological development in COPD. Sixteen healthy control subjects and 104 subjects with chronic bronchitis, with or without pulmonary obstruction at baseline, were investigated. Using both the extent of and change in bronchial obstruction as main scoring criteria for the analysis of gene expression in lung tissue, we identified 410 genes significantly associated with progression of COPD. One hundred ten of these genes demonstrated a distinctive expression pattern, with their functional annotations indicating participation in the regulation of cellular coherence, membrane integrity, growth, and differentiation, as well as inflammation and fibroproliferative repair. The regulatory pattern indicates a sequentially unfolding pathology that centers on a two-step failure of surface integrity commencing with a loss of epithelial coherence as early as chronic bronchitis. Decline of regenerative repair starting in Global Initiative for Chronic Obstructive Lung Disease stage I then activates degradation of extracellular-matrix hyaluronan, causing structural failure of the bronchial wall that is only resolved by scar formation. Although they require independent confirmation, our findings provide the first tangible pathophysiological concept of COPD to be further explored.Clinical trial registered with www.clinicaltrials.gov (NCT00618137).

Random rotation for identifying differentially expressed genes with linear models following batch effect correction.

MOTIVATION: Data generated from high-throughput technologies such as sequencing, microarray and bead-chip technologies are unavoidably affected by batch effects (BEs). Large effort has been put into developing methods for correcting these effects. Often, BE correction and hypothesis testing cannot be done with one single model, but are done successively with separate models in data analysis pipelines. This potentially leads to biased P-values or false discovery rates due to the influence of BE correction on the data. RESULTS: We present a novel approach for estimating null distributions of test statistics in data analysis pipelines where BE correction is followed by linear model analysis. The approach is based on generating simulated datasets by random rotation and thereby retains the dependence structure of genes adequately. This allows estimating null distributions of dependent test statistics, and thus the calculation of resampling-based P-values and false-discovery rates following BE correction while maintaining the alpha level. AVAILABILITY: The described methods are implemented as randRotation package on Bioconductor: https://bioconductor.org/packages/randRotation/. CONTACT: p.hettegger@gmail.com. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

In Planta Production of the Receptor-Binding Domain From SARS-CoV-2 With Human Blood Group A Glycan Structures.

Glycosylation of viral envelope proteins is important for infectivity and immune evasion. The SARS-CoV-2 spike protein is heavily glycosylated and host-derived glycan modifications contribute to the formation of specific immunogenic epitopes, enhance the virus-cell interaction or affect virus transmission. On recombinant viral antigens used as subunit vaccines or for serological assays, distinct glycan structures may enhance the immunogenicity and are recognized by naturally occurring antibodies in human sera. Here, we performed an in vivo glycoengineering approach to produce recombinant variants of the SARS-CoV-2 receptor-binding domain (RBD) with blood group antigens in Nicotiana benthamiana plants. SARS-CoV-2 RBD and human glycosyltransferases for the blood group ABH antigen formation were transiently co-expressed in N. benthamiana leaves. Recombinant RBD was purified and the formation of complex N-glycans carrying blood group A antigens was shown by immunoblotting and MS analysis. Binding to the cellular ACE2 receptor and the conformation-dependent CR3022 antibody showed that the RBD glycosylation variants carrying blood group antigens were functional. Analysis of sera from RBD-positive and RBD-negative individuals revealed further that non-infected RBD-negative blood group O individuals have antibodies that strongly bind to RBD modified with blood group A antigen structures. The binding of IgGs derived from sera of non-infected RBD-negative blood group O individuals to blood group A antigens on SARS-CoV-2 RBD suggests that these antibodies could provide some degree of protection from virus infection.

Gene expression profiling identifies pathways involved in seed maturation of Jatropha curcas.

BACKGROUND: Jatropha curcas, a tropical shrub, is a promising biofuel crop, which produces seeds with high content of oil and protein. To better understand the maturation process of J. curcas seeds and to improve its agronomic performance, a two-step approach was performed in six different maturation stages of seeds: 1) generation of the entire transcriptome of J. curcas seeds using 454-Roche sequencing of a cDNA library, 2) comparison of transcriptional expression levels using a custom Agilent 8x60K oligonucleotide microarray. RESULTS: A total of 793,875 high-quality reads were assembled into 19,382 unique full-length contigs, of which 13,507 could be annotated with Gene Ontology (GO) terms. Microarray data analysis identified 9111 probes (out of 57,842 probes), which were differentially expressed between the six maturation stages. The expression results were validated for 75 selected transcripts based on expression levels, predicted function, pathway, and length. Result from cluster analyses showed that transcripts associated with fatty acid, flavonoid, and phenylpropanoid biosynthesis were over-represented in the early stages, while those of lipid storage were over-represented in the late stages. Expression analyses of different maturation stages of J. curcas seed showed that most changes in transcript abundance occurred between the two last stages, suggesting that the timing of metabolic pathways during seed maturation in J. curcas occurs in late stages. The co-expression results showed that the hubs (CB5-D, CDR1, TT8, DFR, HVA22) with the highest number of edges, associated with fatty acid and flavonoid biosynthesis, are showing a decrease in their expression during seed maturation. Furthermore, seed development and hormone pathways are significantly well connected. CONCLUSION: The obtained results revealed differentially expressed sequences (DESs) regulating important pathways related to seed maturation, which could contribute to the understanding of the complex regulatory network during seed maturation with the focus on lipid, flavonoid and phenylpropanoid biosynthesis. This study provides detailed information on transcriptional changes during J. curcas seed maturation and provides a starting point for a genomic survey of seed quality traits. The results highlighted specific genes and processes relevant to the molecular mechanisms involved in Jatropha seed maturation. These data can also be utilized regarding other Euphorbiaceae species.

EPIC-TABSAT: analysis tool for targeted bisulfite sequencing experiments and array-based methylation studies.

DNA methylation is one of the major epigenetic modifications and has frequently demonstrated its suitability as diagnostic and prognostic biomarker. In addition to chip and sequencing based epigenome wide methylation profiling methods, targeted bisulfite sequencing (TBS) has been established as a cost-effective approach for routine diagnostics and target validation applications. Yet, an easy-to-use tool for the analysis of TBS data in combination with array-based methylation results has been missing. Consequently, we have developed EPIC-TABSAT, a user-friendly web-based application for the analysis of targeted sequencing data that additionally allows the integration of array-based methylation results. The tool can handle multiple targets as well as multiple sequencing files in parallel and covers the complete data analysis workflow from calculation of quality metrics to methylation calling and interactive result presentation. The graphical user interface offers an unprecedented way to interpret TBS data alone or in combination with array-based methylation studies. Together with the computation of target-specific epialleles it is useful in validation, research, and routine diagnostic environments. EPIC-TABSAT is freely accessible to all users at https://tabsat.ait.ac.at/.

Ape1 guides DNA repair pathway choice that is associated with drug tolerance in glioblastoma.

Ape1 is the major apurinic/apyrimidinic (AP) endonuclease activity in mammalian cells, and a key factor in base-excision repair of DNA. High expression or aberrant subcellular distribution of Ape1 has been detected in many cancer types, correlated with drug response, tumor prognosis, or patient survival. Here we present evidence that Ape1 facilitates BRCA1-mediated homologous recombination repair (HR), while counteracting error-prone non-homologous end joining of DNA double-strand breaks. Furthermore, Ape1, coordinated with checkpoint kinase Chk2, regulates drug response of glioblastoma cells. Suppression of Ape1/Chk2 signaling in glioblastoma cells facilitates alternative means of damage site recruitment of HR proteins as part of a genomic defense system. Through targeting "HR-addicted" temozolomide-resistant glioblastoma cells via a chemical inhibitor of Rad51, we demonstrated that targeting HR is a promising strategy for glioblastoma therapy. Our study uncovers a critical role for Ape1 in DNA repair pathway choice, and provides a mechanistic understanding of DNA repair-supported chemoresistance in glioblastoma cells.

New liver cancer biomarkers: PI3K/AKT/mTOR pathway members and eukaryotic translation initiation factors.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. The initiation of protein translation is an important rate-limiting step in eukaryotes and is crucial in many viral infections. Eukaryotic translation initiation factors (eIFs) are involved in the initiation step of protein translation and are linked to the phosphatidylinositol-3-kinases PI3K/AKT/mTOR pathway. Therefore we aimed to investigate a potential role of eIFs in HCC. We herein report on the immunohistochemical expression of the various eIF subunits in 235 cases of virus-related human HCC. Additionally, we used immunoblot analysis to investigate the expression of virus-related HCC and non-virus-related HCC in comparison to controls. Mammalian target of rapamycin (or mechanistic target of rapamycin as it is known now (mTOR) and activated mTOR were significantly increased in chronic hepatitis C (HCV)-associated HCC, in HCC without a viral background, in alcoholic liver disease and Wilson disease. pPTEN, phosphatase and tensin homologue (PTEN) and pAKT showed a significant increase in HBV- and HCV-associated HCC, chronic hepatitis B, HCC without a viral background, alcoholic steatohepatitis (ASH) and Wilson disease. Phosphorylated (p)-eIF2α, eIF2α, eiF3B, eIF3D, eIF3J, p-eIF4B, eIF4G and eIF6 were upregulated in HCV-associated HCC. eIF2α, p-eIF4B, eIF5 and various eIF3 subunits were significantly increased in chronic hepatitis B (HBV)-associated HCC. HCC without viral background displayed a significant increase for the eIF subunits p-2α, 3C, 3I, 4E and 4G. We noticed engraved differences in the expression pattern between chronic hepatitis B and C, HBV- and HCV-associated HCC and non-virus-related HCC.