High-yield synthesis of 2-O-α-D-glucosyl-D-glycerate by a bifunctional glycoside phosphorylase

Osmolytes are produced by various microorganisms as a defense mechanism to protect cells and macromolecules from damage caused by external stresses in harsh environments. Due to their useful stabilizing properties, these molecules are applied as active ingredients in a wide range of cosmetics and healthcare products. The metabolic pathways and biocatalytic syntheses of glycosidic osmolytes such as 2-O-α-D-glucosyl-D-glycerate often involve the action of a glycoside phosphorylase. Here, we report the discovery of a glucosylglycerate phosphorylase from carbohydrate-active enzyme family GH13 that is also active on sucrose, which contrasts the strict specificity of known glucosylglycerate phosphorylases that can only use α-D-glucose 1-phosphate as glycosyl donor in transglycosylation reactions. The novel enzyme can be distinguished from other phosphorylases from the same family by the presence of an atypical conserved sequence motif at specificity-determining positions in the active site. The promiscuity of the sucrose-active glucosylglycerate phosphorylase can be exploited for the high-yielding and rapid synthesis of 2-O-α-D-glucosyl-D-glycerate from sucrose and D-glycerate. KEY POINTS: • A Xylanimonas protaetiae glycoside phosphorylase can use both d-glycerate and fructose as glucosyl acceptor with high catalytic efficiency • Biocatalytic synthesis of the osmolyte 2-O-α-d-glucosyl-d-glycerate • Positions in the active site of GH13 phosphorylases act as convenient specificity fingerprints.

Endolysin NC5 improves early cloxacillin treatment in a mouse model of Streptococcus uberis mastitis

Streptococcus uberis frequently causes bovine mastitis, an infectious udder disease with significant economic implications for dairy cows. Conventional antibiotics, such as cloxacillin, sometimes have limited success in eliminating S. uberis as a stand-alone therapy. To address this challenge, the study objective was to investigate the VersaTile engineered endolysin NC5 as a supplemental therapy to cloxacillin in a mouse model of bovine S. uberis mastitis. NC5 was previously selected based on its intracellular killing and biofilm eradicating activity. To deliver preclinical proof-of-concept of this supplemental strategy, lactating mice were intramammarily infected with a bovine S. uberis field isolate and subsequently treated with cloxacillin (30.0 μg) combined with either a low (23.5 μg) or high (235.0 μg) dose of NC5. An antibiotic monotherapy group, as well as placebo treatment, was included as controls. Two types of responders were identified: fast (n = 17), showing response after 4-h treatment, and slow (n = 10), exhibiting no clear response at 4 h post-treatment across all groups. The high-dose combination therapy in comparison with placebo treatment impacted the hallmarks of mastitis in the fast responders by reducing (i) the bacterial load 13,000-fold (4.11 ± 0.78 Δlog10; p < 0.001), (ii) neutrophil infiltration 5.7-fold (p > 0.05), and (iii) the key pro-inflammatory chemokine IL-8 13-fold (p < 0.01). These mastitis hallmarks typically followed a dose response dependent on the amount of endolysin added. The current in vivo study complements our in vitro data and provides preclinical proof-of-concept of NC5 as an adjunct to intramammary cloxacillin treatment. KEY POINTS: • Engineered endolysin NC5 was preclinically evaluated as add-on to cloxacillin treatment. • Two types of mice (slow and fast responding) were observed. • The add-on treatment decreased bacterial load, neutrophil influx, and pro-inflammatory mediators.

Cavity-Directed Synthesis of Labile Polyoxometalates for Catalysis in Confined Spaces

The artificial microenvironments inside coordination cages have gained significant attention for performing enzyme-like catalytic reactions by facilitating the formation of labile and complex molecules through a "ship-in-a-bottle" approach. Despite many fascinating examples, this approach remains scarcely explored in the context of synthesizing metallic clusters such as polyoxometalates (POMs). The development of innovative approaches to control and influence the speciation of POMs in aqueous solutions would greatly advance their applicability and could ultimately lead to the formation of elusive clusters that cannot be synthesized by using traditional methods. In this study, we employ host-guest stabilization within a coordination cage to enable a novel cavity-directed synthesis of labile POMs in aqueous solutions under mild conditions. The elusive Lindqvist [M6O19]2- (M=Mo or W) POMs were successfully synthesized at room temperature via the condensation of molybdate or tungstate building blocks within the confined cavity of a robust and water-soluble Pt6L4(NO3)12 coordination cage. Importantly, the encapsulation of these POMs enhances their stability in water, rendering them efficient catalysts for environmentally friendly and selective sulfoxidation reactions using H2O2 as a green oxidant in a pure aqueous medium. The approach developed in this paper offers a means to synthesize and stabilize the otherwise unstable metal-oxo clusters in water, which can broaden the scope of their applications.

Staying on track - Keeping things running in a high-end scientific imaging core facility

Modern life science research is a collaborative effort. Few research groups can single-handedly support the necessary equipment, expertise and personnel needed for the ever-expanding portfolio of technologies that are required across multiple disciplines in today's life science endeavours. Thus, research institutes are increasingly setting up scientific core facilities to provide access and specialised support for cutting-edge technologies. Maintaining the momentum needed to carry out leading research while ensuring high-quality daily operations is an ongoing challenge, regardless of the resources allocated to establish such facilities. Here, we outline and discuss the range of activities required to keep things running once a scientific imaging core facility has been established. These include managing a wide range of equipment and users, handling repairs and service contracts, planning for equipment upgrades, renewals, or decommissioning, and continuously upskilling while balancing innovation and consolidation.

Prevalence of hypersensitivity reactions in various forms of mastocytosis: A pilot study of 2485 adult patients with mastocytosis collected in the ECNM registry

BACKGROUND

Hypersensitivity reactions (HR) are common in mastocytosis. However, little is known about triggers and risk factors. The registry of the European Competence Network on Mastocytosis (ECNM) enables reliable studies in a larger cohort of mastocytosis patients. We assessed prevalence, triggers and risk factors of HR in adults with mastocytosis in the ECNM registry.

METHODS

Data were collected in 27 ECNM centers. We analyzed potential triggers (Hymenoptera venoms, food, drug, inhalant and others) and risk factors at diagnosis and during follow-up. The study group consisted of 2485 adults with mastocytosis, 1379 women (55.5%) and 1106 men (44.5%). Median age was 48.2 years (range 18-91 years).

RESULTS

Nine hundred and forty eight patients (38.1%) reported one or more HR`. Most common triggers were Hymenoptera venoms in cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM), whereas in advanced SM (advSM), most common elicitors were drugs, including nonsteroidal anti-inflammatory agents and penicillin. In multivariate analyses, tryptase level < 90 ng/mL, <15% infiltration by mast cells in bone marrow biopsy-sections, and diagnosis of ISM were identified as independent risk factors for HR. For drug-induced HR, prominent risk factors were advSM and high tryptase levels. New reactions were observed in 4.8% of all patients during 4 years follow-up.

CONCLUSIONS

HR are mainly triggered by Hymenoptera venoms in patients with CM and ISM and by drugs in patients with advSM. Tryptase levels <90 ng/mL, mast cell bone marrow infiltration <15%, and WHO category ISM are predictors of HR. New HR occur in 4.8% of all patients within 4 years.

The future burden of type 2 diabetes in Belgium: a microsimulation model

OBJECTIVE

To forecast the annual burden of type 2 diabetes and related socio-demographic disparities in Belgium until 2030.

METHODS

This study utilized a discrete-event transition microsimulation model. A synthetic population was created using 2018 national register data of the Belgian population aged 0-80 years, along with the national representative prevalence of diabetes risk factors obtained from the latest (2018) Belgian Health Interview and Examination Surveys using Multiple Imputation by Chained Equations (MICE) as inputs to the Simulation of Synthetic Complex Data (simPop) model. Mortality information was obtained from the Belgian vital statistics and used to calculate annual death probabilities. From 2018 to 2030, synthetic individuals transitioned annually from health to death, with or without developing type 2 diabetes, as predicted by the Finnish Diabetes Risk Score, and risk factors were updated via strata-specific transition probabilities.

RESULTS

A total of 6722 [95% UI 3421, 11,583] new cases of type 2 diabetes per 100,000 inhabitants are expected between 2018 and 2030 in Belgium, representing a 32.8% and 19.3% increase in T2D prevalence rate and DALYs rate, respectively. While T2D burden remained highest for lower-education subgroups across all three Belgian regions, the highest increases in incidence and prevalence rates by 2030 are observed for women in general, and particularly among Flemish women reporting higher-education levels with a 114.5% and 44.6% increase in prevalence and DALYs rates, respectively. Existing age- and education-related inequalities will remain apparent in 2030 across all three regions.

CONCLUSIONS

The projected increase in the burden of T2D in Belgium highlights the urgent need for primary and secondary preventive strategies. While emphasis should be placed on the lower-education groups, it is also crucial to reinforce strategies for people of higher socioeconomic status as the burden of T2D is expected to increase significantly in this population segment.

Against age limits for men in reproductive care

Almost all countries and fertility clinics impose age limits on women who want to become pregnant through Assisted Reproductive Technologies (ART). Age limits for aspiring fathers, however, are much less common and remain a topic of debate. This article departs from the principle of reproductive autonomy and a conditional positive right to receive ART, and asks whether there are convincing arguments to also impose age limits on aspiring fathers. After considering three consequentialist approaches to justifying age limits for aspiring fathers, we take in a concrete normative stance by concluding that those are not strong enough to justify such cut-offs. We reinforce our position by drawing a comparison between the case of a 39-year-old woman who wants to become a single mother via a sperm donor on the one hand, and on the other hand the same woman who wants to have a child with a 64-year-old man who she loves and who is willing to care for the child as long as he is able to. We conclude that, as long as appropriate precautions are taken to protect the welfare of the future child, couples who want to receive fertility treatment should never be limited on the basis of the age of the (male) partner. An absence of age limits for men would respect the reproductive autonomy of both the man and the woman.

The identification of requirements for competency development during work-integrated learning in healthcare education

BACKGROUND

Work-integrated learning (WIL) is widely accepted and necessary to attain the essential competencies healthcare students need at their future workplaces. Yet, competency-based education (CBE) remains complex. There often is a focus on daily practice during WIL. Hereby, continuous competency development is at stake. Moreover, the fact that competencies need to continuously develop is often neglected.

OBJECTIVES

To ultimately contribute to the optimization of CBE in healthcare education, this study aimed at examining how competency development during WIL in healthcare education could be optimized, before and after graduation.

METHODS

Fourteen semi-structured interviews with 16 experts in competency development and WIL were carried out. Eight healthcare disciplines were included namely associate degree nursing, audiology, family medicine, nursing (bachelor), occupational therapy, podiatry, pediatrics, and speech therapy. Moreover, two independent experts outside the healthcare domain were included to broaden the perspectives on competency development. A qualitative research approach was used based on an inductive thematic analysis using Nvivo12© where 'in vivo' codes were clustered as sub-themes and themes.

RESULTS

The analysis revealed eight types of requirements for effective and continuous competency development, namely requirements in the context of (1) competency frameworks, (2) reflection and feedback, (3) assessment, (4) the continuity of competency development, (5) mentor involvement, (6) ePortfolios, (7) competency development visualizations, and (8) competency development after graduation. It was noteworthy that certain requirements were fulfilled in one educational program whereas they were absent in another. This emphasizes the large differences in how competence-based education is taking shape in different educational programs and internship contexts. Nevertheless, all educational programs seemed to recognize the importance of ongoing competency development.

CONCLUSION

The results of this study indicate that identifying and meeting the requirements for effective and continuous competency development is essential to optimize competency development during practice in healthcare education.

An exact algorithm to find a maximum weight clique in a weighted undirected graph

We introduce a new algorithm MaxCliqueWeight for identifying a maximum weight clique in a weighted graph, and its variant MaxCliqueDynWeight with dynamically varying bounds. This algorithm uses an efficient branch-and-bound approach with a new weighted graph coloring algorithm that efficiently determines upper weight bounds for a maximum weighted clique in a graph. We evaluate our algorithm on random weighted graphs with node counts up to 10,000 and on standard DIMACS benchmark graphs used in a variety of research areas. Our findings reveal a remarkable improvement in computational speed when compared to existing algorithms, particularly evident in the case of high-density random graphs and DIMACS graphs, where our newly developed algorithm outperforms existing alternatives by several orders of magnitude. The newly developed algorithm and its variant are freely available to the broader research community at http://insilab.org/maxcliqueweight , paving the way for transformative applications in various research areas, including drug discovery.

The Clinical Relevance of the Infiltrating Immune Cell Composition in Kidney Transplant Rejection

BACKGROUND

The link between the histology of kidney transplant rejection, especially Antibody-mediated rejection, T cell-mediated rejection and Mixed rejection, and the types of infiltrating immune cells is currently not well charted. Cost and technical complexity of single cell analysis hinder large scale studies of the relationship between cell infiltrate profiles and histological heterogeneity.

METHODS

In this cross-sectional study, we assessed the composition of nine intragraft immune cell types by using a validated kidney transplant-specific signature matrix for deconvolution of bulk transcriptomics in three different kidney transplant biopsy datasets (N=403, N=224, N=282). The association and the discrimination of the immune cell types with the Banff histology and the association with graft failure were assessed individually and with multivariable models. Unsupervised clustering algorithms were applied on the overall immune cells composition and compared to the Banff phenotypes.

RESULTS

Banff-defined rejection was related to high presence of CD8+ effector T cells, Natural Killer cells, monocytes/macrophages and to a lesser extent B cells, whereas CD4+ memory T cells were lower in rejection compared to no rejection. Estimated intragraft effector memory-expressing CD45RA (TEMRA) CD8+ T cells were strongly and consistently associated with graft failure. The large heterogeneity in immune cell composition across rejection types prevented supervised and unsupervised methods to accurately recover the Banff phenotypes based solely on immune cell estimates. The lack of correlation between immune cell composition and Banff-defined rejection types was validated using multiplex immunohistochemistry.

CONCLUSIONS

Although some specific cell types (FCGR3A+ myeloid cells, CD14+ monocytes/macrophages and NK cells), partly discriminate between rejection phenotypes, the overall estimated immune cell composition of kidney transplants is ill related to main Banff-defined rejection categories and adds to the Banff lesion scoring and evaluation of rejection severity. The estimated intragraft CD8temra cells bear strong and consistent association with graft failure and independent of Banff-grade rejection.

Aspecific binding of anti-NK1.1 antibodies on myeloid cells in an experimental model for malaria-associated acute respiratory distress syndrome

BACKGROUND

Conventional natural killer (cNK) cells play an important role in the innate immune response by directly killing infected and malignant cells and by producing pro- and anti-inflammatory cytokines. Studies on their role in malaria and its complications have resulted in conflicting results.

METHODS

Using the commonly used anti-NK1.1 depletion antibodies (PK136) in an in-house optimized experimental model for malaria-associated acute respiratory distress syndrome (MA-ARDS), the role of cNK cells was investigated. Moreover, flow cytometry was performed to characterize different NK cell populations.

RESULTS

While cNK cells were found to be dispensable in the development of MA-ARDS, the appearance of a NK1.1+ cell population was observed in the lungs upon infection despite depletion with anti-NK1.1. Detailed characterization of the unknown population revealed that this population consisted of a mixture of monocytes and macrophages that bind the anti-NK1.1 antibody in an aspecific way. This aspecific binding may occur via Fcγ receptors, such as FcγR4. In contrast, in vivo depletion using anti-NK1.1 antibodies was proved to be specific for cNK cells.

CONCLUSION

cNK cells are dispensable in the development of experimental MA-ARDS. Moreover, careful flow cytometric analysis, with a critical mindset in relation to potential aspecific binding despite the use of commercially available Fc blocking reagents, is critical to avoid misinterpretation of the results.

From Gel to Crystal: Mechanism of HfO2 and ZrO2 Nanocrystal Synthesis in Benzyl Alcohol

Nonaqueous sol-gel syntheses have been used to make many types of metal oxide nanocrystals. According to the current paradigm, nonaqueous syntheses have slow kinetics, thus favoring the thermodynamic (crystalline) product. Here we investigate the synthesis of hafnium (and zirconium) oxide nanocrystals from the metal chloride in benzyl alcohol. We follow the transition from precursor to nanocrystal through a combination of rheology, EXAFS, NMR, TEM, and X-ray total scattering (PDF analysis). Upon dissolving the metal chloride precursor, the exchange of chloride ligands for benzylalkoxide liberates HCl. The latter catalyzes the etherification of benzyl alcohol, eliminating water. During the temperature ramp to the reaction temperature (220 °C), sufficient water is produced to turn the reaction mixture into a macroscopic gel. Rheological analysis shows a network consisting of strong interactions with temperature-dependent restructuring. After a few minutes at the reaction temperature, crystalline particles emerge from the gel, and nucleation and growth are complete after 30 min. In contrast, 4 h are required to obtain the highest isolated yield, which we attribute to the slow in situ formation of water (the extraction solvent). We used our mechanistic insights to optimize the synthesis, achieving high isolated yields with a reduced reaction time. Our results oppose the idea that nonaqueous sol-gel syntheses necessarily form crystalline products in one step, without a transient, amorphous gel state.

The relation between meniscal dynamics and tibiofemoral kinematics

Over the past 30 years, research on meniscal kinematics has been limited by challenges such as low-resolution imaging and capturing continuous motion from static data. This study aimed to develop a computational knee model that overcomes these limitations and enables the continuous assessment of meniscal dynamics. A high-resolution MRI dataset (n = 11) was acquired in 4 configurations of knee flexion. In each configuration, the menisci were modeled based on the underlying osseous anatomy. Principal Polynomial Shape Analysis (PPSA) was employed for continuous meniscal modeling. Maximal medial anterior horn displacement occurred in 60° of flexion, equaling 6.24 mm posteromedial, while the posterior horn remained relatively stable. At 90° of flexion, the lateral anterior and posterior horn displaced posteromedially, amounting 5.70 mm and 6.51 mm respectively. The maximal observed Average Surface Distance (ASD) equaled 0.70 mm for lateral meniscal modeling in 90° of flexion. Based on our results, a strong relation between meniscal dynamics and tibiofemoral kinematics was confirmed. Expanding on static meniscal modeling and employing PPSA, we derived and validated a standardized and systematic methodological workflow.

Photopharmacology of Protease Inhibitors: Current Status and Perspectives

Proteases are involved in many essential biological processes. Dysregulation of their activity underlies a wide variety of human diseases. Photopharmacology, as applied on various classes of proteins, has the potential to assist protease research by enabling spatiotemporal control of protease activity. Moreover, it may be used to decrease side-effects of protease-targeting drugs. In this review, we discuss the current status of the chemical design of photoactivatable proteases inhibitors and their biological application. Additionally, we give insight into future possibilities for further development of this field of research.

Exploiting G-Quadruplex-DNA Damage as a Tool to Quantify Singlet Oxygen Production

G-Quadruplexes (G4s) are highly dynamic and polymorphic nucleic acid structures that can adopt a variety of conformations. When exposed to oxidative conditions, more specifically singlet oxygen, the guanosine nucleobases can be oxidized, which in turn can affect the conformation and folding of the G4. Based on this peculiar phenomenon, it is rationalized that G4s can serve as quantification sensors for the production of singlet oxygen. Here, a method for determining the quantum yield of singlet oxygen generation for visible as well as UV-light excited photosensitizers, using a short G4 DNA sequence, readily available from common DNA companies, as a biological and water-soluble probe, is presented.

Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington's disease

BACKGROUND

Huntington's disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have been shown to lead to dysregulated energy supply to brain regions in several neurological diseases, including HD, which could potentially trigger the process of neurodegeneration. In particular, it has been observed in cross-sectional human HD studies that vascular alterations are associated to impaired cerebral blood flow (CBF). To assess whether whole-brain changes in CBF are present and follow a pattern of progression, we investigated both resting-state brain perfusion and vascular reactivity longitudinally in the zQ175DN mouse model of HD.

METHODS

Using pseudo-continuous arterial spin labelling (pCASL) MRI in the zQ175DN model of HD and age-matched wild-type (WT) mice, we assessed whole-brain, resting-state perfusion at 3, 6 and 9 and 13 months of age, and assessed hypercapnia-induced cerebrovascular reactivity (CVR), at 4.5, 6, 9 and 15 months of age.

RESULTS

We found increased perfusion in cortical regions of zQ175DN HET mice at 3 months of age, and a reduction of this anomaly at 6 and 9 months, ages at which behavioural deficits have been reported. On the other hand, under hypercapnia, CBF was reduced in zQ175DN HET mice as compared to the WT: for multiple brain regions at 6 months of age, for only somatosensory and retrosplenial cortices at 9 months of age, and brain-wide by 15 months. CVR impairments in cortical regions, the thalamus and globus pallidus were observed in zQ175DN HET mice at 9 months, with whole brain reactivity diminished at 15 months of age. Interestingly, blood vessel density was increased in the motor cortex at 3 months, while average vessel length was reduced in the lateral portion of the caudate putamen at 6 months of age.

CONCLUSION

Our findings reveal early cortical resting-state hyperperfusion and impaired CVR at ages that present motor anomalies in this HD model, suggesting that further characterization of brain perfusion alterations in animal models is warranted as a potential therapeutic target in HD.

Oral Biofilm Composition, Dissemination to Keratinocytes, and Inflammatory Attenuation Depend on Probiotic and Synbiotic Strain Specificity

Several inflammatory diseases are characterized by a disruption in the equilibrium between the host and its microbiome. Due to the increase in resistance, the use of antibiotics for the widespread, nonspecific killing of microorganisms is at risk. Pro-microbial approaches focused on stimulating or introducing beneficial species antagonistic toward pathobionts may be a viable alternative for restoring the host-microbiome equilibrium. Unfortunately, not all potential probiotic or synbiotic species and even subspecies (to strain level) are equally effective for the designated pathology, leading to conflicting accounts of their efficacy. To assess the extent of these species- and strain-specific effects, 13 probiotic candidates were evaluated for their probiotic and synbiotic potential with glycerol on in vitro oral biofilms, dissemination from biofilms to keratinocytes, and anti-inflammatory activity. Species- and strain-specific effects and efficacies were observed in how they functioned as probiotics or synbiotics by influencing oral pathobionts and commensals within biofilms and affected the dissemination of pathobionts to keratinocytes, ranging from ineffective strains to strains that reduced pathobionts by 3 + log. In addition, a minority of the candidates exhibited the ability to mitigate the inflammatory response of LPS-stimulated monocytes. For a comprehensive assessment of probiotic therapy for oral health, a judicious selection of fully characterized probiotic strains that are specifically tailored to the designated pathology is required. This approach aims to challenge the prevailing perception of probiotics, shifting the focus away from "form over function." Rather than using unproven, hypothetical probiotic strains from known genera or species, one should choose strains that are actually functional in resolving the desired pathology before labelling them probiotics.

Strategies for the synthesis of the osmolyte glucosylglycerate and its precursor glycerate

Glycosidic osmolytes are widespread natural compounds that protect microorganisms and their macromolecules from the deleterious effects of various environmental stresses. Their protective properties have attracted considerable interest for industrial applications, especially as active ingredients in cosmetics and healthcare products. In that regard, the osmolyte glucosylglycerate is somewhat overlooked. Glucosylglycerate is typically accumulated by certain organisms when they are exposed to high salinity and nitrogen starvation, and its potent stabilizing effects have been demonstrated in vitro. However, the applications of this osmolyte have not been thoroughly explored due to the lack of a cost-efficient production process. Here, we present an overview of the progress that has been made in developing promising strategies for the synthesis of glucosylglycerate and its precursor glycerate, and discuss the remaining challenges. KEY POINTS: • Bacterial milking could be explored for fermentative production of glucosylglycerate • Glycoside phosphorylases of GH13_18 represent attractive alternatives for biocatalytic production • Conversion of glycerol with alditol oxidase is a promising strategy for generating the precursor glycerate.

Chitin-mediated blockade of chitinase-like proteins reduces tumor immunosuppression, inhibits lymphatic metastasis and enhances anti-PD-1 efficacy in complementary TNBC models

BACKGROUND

Chitinase-like proteins (CLPs) play a key role in immunosuppression under inflammatory conditions such as cancer. CLPs are enzymatically inactive and become neutralized upon binding of their natural ligand chitin, potentially reducing CLP-driven immunosuppression. We investigated the efficacy of chitin treatment in the context of triple-negative breast cancer (TNBC) using complementary mouse models. We also evaluated the immunomodulatory influence of chitin on immune checkpoint blockade (ICB) and compared its efficacy as general CLP blocker with blockade of a single CLP, i.e. chitinase 3-like 1 (CHI3L1).

METHODS

Female BALB/c mice were intraductally injected with luciferase-expressing 4T1 or 66cl4 cells and systemically treated with chitin in combination with or without anti-programmed death (PD)-1 ICB. For single CLP blockade, tumor-bearing mice were treated with anti-CHI3L1 antibodies. Metastatic progression was monitored through bioluminescence imaging. Immune cell changes in primary tumors and lymphoid organs (i.e. axillary lymph nodes and spleen) were investigated through flow cytometry, immunohistochemistry, cytokine profiling and RNA-sequencing. CHI3L1-stimulated RAW264.7 macrophages were subjected to 2D lymphatic endothelial cell adhesion and 3D lymphatic integration in vitro assays for studying macrophage-mediated lymphatic remodeling.

RESULTS

Chitin significantly reduced primary tumor progression in the 4T1-based model by decreasing the high production of CLPs that originate from tumor-associated neutrophils (TANs) and Stat3 signaling, prominently affecting the CHI3L1 and CHI3L3 primary tumor levels. It reduced immunosuppressive cell types and increased anti-tumorigenic T-cells in primary tumors as well as axillary lymph nodes. Chitin also significantly reduced CHI3L3 primary tumor levels and immunosuppression in the 66cl4-based model. Compared to anti-CHI3L1, chitin enhanced primary tumor growth reduction and anti-tumorigenicity. Both treatments equally inhibited lymphatic adhesion and integration of macrophages, thereby hampering lymphatic tumor cell spreading. Upon ICB combination therapy, chitin alleviated anti-PD-1 resistance in both TNBC models, providing a significant add-on reduction in primary tumor and lung metastatic growth compared to chitin monotherapy. These add-on effects occurred through additional increase in CD8α+ T-cell infiltration and activation in primary tumor and lymphoid organs.

CONCLUSIONS

Chitin, as a general CLP blocker, reduces CLP production, enhances anti-tumor immunity as well as ICB responses, supporting its potential clinical relevance in immunosuppressed TNBC patients.

Determining the exposure of maternal medicines through breastfeeding: the UmbrelLACT study protocol-a contribution from the ConcePTION project

INTRODUCTION

Breastfeeding is beneficial for the health of the mother and child. However, at least 50% of postpartum women need pharmacotherapy, and this number is rising due to the increasing prevalence of chronic diseases and pregnancies at a later age. Making informed decisions on medicine use while breastfeeding is often challenging, considering the extensive information gap on medicine exposure and safety during lactation. This can result in the unnecessary cessation of breastfeeding, the avoidance of pharmacotherapy or the off-label use of medicines. The UmbrelLACT study aims to collect data on human milk transfer of maternal medicines, child exposure and general health outcomes. Additionally, the predictive performance of lactation and paediatric physiologically based pharmacokinetic (PBPK) models, a promising tool to predict medicine exposure in special populations, will be evaluated.

METHODS AND ANALYSIS

Each year, we expect to recruit 5-15 breastfeeding mothers using pharmacotherapy via the University Hospitals Leuven, the BELpREG project (pregnancy registry in Belgium) or external health facilities. Each request and compound will be evaluated on relevance (ie, added value to available scientific evidence) and feasibility (including access to analytical assays). Participants will be requested to complete at least one questionnaire on maternal and child's general health and collect human milk samples over 24 hours. Optionally, two maternal and one child's blood samples can be collected. The maternal medicine concentration in human milk will be determined along with the estimation of the medicine intake (eg, daily infant dose and relative infant dose) and systemic exposure of the breastfed child. The predictive performance of PBPK models will be assessed by comparing the observed concentrations in human milk and plasma to the PBPK predictions.

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee Research UZ/KU Leuven (internal study number S67204). Results will be published in peer-reviewed journals and presented at (inter)national scientific meetings.

TRIAL REGISTRATION NUMBER

NCT06042803.

C-TERMINAL DOMAIN PHOSPHATASE-LIKE 3 contributes to GA-mediated growth and flowering by interaction with DELLA proteins

Gibberellic acid (GA) plays a central role in many plant developmental processes and is crucial for crop improvement. DELLA proteins, the core suppressors in the GA signaling pathway, are degraded by GA via the 26S proteasomal pathway to release the GA response. However, little is known about the phosphorylation-mediated regulation of DELLA proteins. In this study, we combined GA response assays with protein-protein interaction analysis to infer the connection between Arabidopsis thaliana DELLAs and the C-TERMINAL DOMAIN PHOSPHATASE-LIKE 3 (CPL3), a phosphatase involved in the dephosphorylation of RNA polymerase II. We show that CPL3 directly interacts with DELLA proteins and promotes DELLA protein stability by inhibiting its degradation by the 26S proteasome. Consequently, CPL3 negatively modulates multiple GA-mediated processes of plant development, including hypocotyl elongation, flowering time, and anthocyanin accumulation. Taken together, our findings demonstrate that CPL3 serves as a novel regulator that could improve DELLA stability and thereby participate in GA signaling transduction.

Evaluating the Efficiency of Boron Nitride Coating in Single-Walled Carbon-Nanotube-Based 1D Heterostructure Films by Optical Spectroscopy

Single-walled carbon nanotube (SWCNT) films exhibit exceptional optical and electrical properties, making them highly promising for scalable integrated devices. Previously, we employed SWCNT films as templates for the chemical vapor deposition (CVD) synthesis of one-dimensional heterostructure films where boron nitride nanotubes (BNNTs) and molybdenum disulfide nanotubes (MoS2NTs) were coaxially nested over the SWCNT networks. In this work, we have further refined the synthesis method to achieve precise control over the BNNT coating in SWCNT@BNNT heterostructure films. The resulting structure of the SWCNT@BNNT films was thoroughly characterized using a combination of electron microscopy, UV-vis-NIR spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. Specifically, we investigated the pressure effect induced by BNNT wrapping on the SWCNTs in the SWCNT@BNNT heterostructure film and demonstrated that the shifts of the SWCNT's G and 2D (G') modes in Raman spectra can be used as a probe of the efficiency of BNNT coating. In addition, we studied the impact of vacuum annealing on the removal of the initial doping in SWCNTs, arising from exposure to ambient atmosphere, and examined the effect of MoO3 doping in SWCNT films by using UV-vis-NIR spectroscopy and Raman spectroscopy. We show that through correlation analysis of the G and 2D (G') modes in Raman spectra, it is possible to discern distinct types of doping effects as well as the influence of applied pressure on the SWCNTs within SWCNT@BNNT heterostructure films. This work contributes to a deeper understanding of the strain and doping effect in both SWCNTs and SWCNT@BNNTs, thereby providing valuable insights for future applications of carbon-nanotube-based one-dimensional heterostructures.

Shaping brassinosteroid signaling through scaffold proteins

Cellular responses to internal and external stimuli are orchestrated by intricate intracellular signaling pathways. To ensure an efficient and specific information flow, cells employ scaffold proteins as critical signaling organizers. With the ability to bind multiple signaling molecules, scaffold proteins can sequester signaling components within specific subcellular domains or modulate the efficiency of signal transduction. Scaffolds can also tune the output of signaling pathways by serving as regulatory targets. This review focuses on scaffold proteins associated with the plant GLYCOGEN SYNTHASE KINASE3-like kinase, BRASSINOSTEROID-INSENSITIVE2 (BIN2) that serve as a key negative regulator of brassinosteroid (BR) signaling. Here we summarize the current understanding of how scaffold proteins actively shape BR signaling outputs and crosstalk in plant cells via interactions with BIN2.

Enhanced accuracy through machine learning-based simultaneous evaluation: a case study of RBS analysis of multinary materials

We address the high accuracy and precision demands for analyzing large in situ or in operando spectral data sets. A dual-input artificial neural network (ANN) algorithm enables the compositional and depth-sensitive analysis of multinary materials by simultaneously evaluating spectra collected under multiple experimental conditions. To validate the developed algorithm, a case study was conducted analyzing complex Rutherford backscattering spectrometry (RBS) spectra collected in two scattering geometries. The dual-input ANN analysis excelled in providing a systematic analysis and precise results, showcasing its robustness in handling complex data and minimizing user bias. A comprehensive comparison with human supervision analysis and conventional single-input ANN analysis revealed a reduced susceptibility of the dual-input ANN analysis to inaccurately known setup parameters, a common challenge in material characterization. The developed multi-input approach can be extended to a wide range of analytical techniques, in which the combined analysis of measurements performed under different experimental conditions is beneficial for disentangling details of the material properties.

Residual Cystine Transport Activity for Specific Infantile and Juvenile CTNS Mutations in a PTEC-Based Addback Model

Cystinosis is a rare, autosomal recessive, lysosomal storage disease caused by mutations in the gene CTNS, leading to cystine accumulation in the lysosomes. While cysteamine lowers the cystine levels, it does not cure the disease, suggesting that CTNS exerts additional functions besides cystine transport. This study investigated the impact of infantile and juvenile CTNS mutations with discrepant genotype/phenotype correlations on CTNS expression, and subcellular localisation and function in clinically relevant cystinosis cell models to better understand the link between genotype and CTNS function. Using CTNS-depleted proximal tubule epithelial cells and patient-derived fibroblasts, we expressed a selection of CTNSmutants under various promoters. EF1a-driven expression led to substantial overexpression, resulting in CTNS protein levels that localised to the lysosomal compartment. All CTNSmutants tested also reversed cystine accumulation, indicating that CTNSmutants still exert transport activity, possibly due to the overexpression conditions. Surprisingly, even CTNSmutants expression driven by the less potent CTNS and EFS promoters reversed the cystine accumulation, contrary to the CTNSG339R missense mutant. Taken together, our findings shed new light on CTNS mutations, highlighting the need for robust assessment methodologies in clinically relevant cellular models and thus paving the way for better stratification of cystinosis patients, and advocating for the development of more personalized therapy.

Azasulfur(iv) derivatives of sulfite and sulfinate esters by formal S-S bond insertion of dichloramines

Azasulfur(vi) compounds such as sulfoximines and sulfonimidamides are attractive due to the unique properties of the S[double bond, length as m-dash]N bond. While the synthesis of these carbon-attached sulfonimidoyl derivatives is well-established, the situation is different for their heteroatom-bound counterparts. In this work, we propose azasulfur(iv) esters as platform chemicals that can be derivatized to obtain all types of SVI[double bond, length as m-dash]N functional groups, among these are the poorly accessible, all-heteroatom imidosulfate esters. Using a chloroamination workflow established here, S-S bond-containing structures such as elemental sulfur or diaryl disulfides can be transformed into imidothionyl or sulfinimidoyl chlorides, which are easily esterified or amidated. Thus, chloramines serve as a versatile [N] and [Cl+] source, and by using them in the context reported here, we advance the set of mild synthetic methods as the latest toolbox member to cover even more of the azasulfur(iv) and (vi) chemical space.

Still in Search for an EAAT Activator: GT949 Does Not Activate EAAT2, nor EAAT3 in Impedance and Radioligand Uptake Assays

Excitatory amino acid transporters (EAATs) are important regulators of amino acid transport and in particular glutamate. Recently, more interest has arisen in these transporters in the context of neurodegenerative diseases. This calls for ways to modulate these targets to drive glutamate transport, EAAT2 and EAAT3 in particular. Several inhibitors (competitive and noncompetitive) exist to block glutamate transport; however, activators remain scarce. Recently, GT949 was proposed as a selective activator of EAAT2, as tested in a radioligand uptake assay. In the presented research, we aimed to validate the use of GT949 to activate EAAT2-driven glutamate transport by applying an innovative, impedance-based, whole-cell assay (xCELLigence). A broad range of GT949 concentrations in a variety of cellular environments were tested in this assay. As expected, no activation of EAAT3 could be detected. Yet, surprisingly, no biological activation of GT949 on EAAT2 could be observed in this assay either. To validate whether the impedance-based assay was not suited to pick up increased glutamate uptake or if the compound might not induce activation in this setup, we performed radioligand uptake assays. Two setups were utilized; a novel method compared to previously published research, and in a reproducible fashion copying the methods used in the existing literature. Nonetheless, activation of neither EAAT2 nor EAAT3 could be observed in these assays. Furthermore, no evidence of GT949 binding or stabilization of purified EAAT2 could be observed in a thermal shift assay. To conclude, based on experimental evidence in the present study GT949 requires specific assay conditions, which are difficult to reproduce, and the compound cannot simply be classified as an activator of EAAT2 based on the presented evidence. Hence, further research is required to develop the tools needed to identify new EAAT modulators and use their potential as a therapeutic target.

Time-dependent complexity characterisation of activity patterns in patients with Chronic Fatigue Syndrome

BACKGROUND

Chronic Fatigue Syndrome patients suffer from symptoms that cannot be explained by a single underlying biological cause. It is sometimes claimed that these symptoms are a manifestation of a disrupted autonomic nervous system. Prior works studying this claim from the complex adaptive systems perspective, have observed a lower average complexity of physical activity patterns in chronic fatigue syndrome patients compared to healthy controls. To further study the robustness of such methods, we investigate the within-patient changes in complexity of activity over time. Furthermore, we explore how these changes might be related to changes in patient functioning.

METHODS

We propose an extension of the allometric aggregation method, which characterises the complexity of a physiological signal by quantifying the evolution of its fractal dimension. We use it to investigate the temporal variations in within-patient complexity. To this end, physical activity patterns of 7 patients diagnosed with chronic fatigue syndrome were recorded over a period of 3 weeks. These recordings are accompanied by physicians' judgements in terms of the patients' weekly functioning.

RESULTS

We report significant within-patient variations in complexity over time. The obtained metrics are shown to depend on the range of timescales for which these are evaluated. We were unable to establish a consistent link between complexity and functioning on a week-by-week basis for the majority of the patients.

CONCLUSIONS

The considerable within-patient variations of the fractal dimension across scales and time force us to question the utility of previous studies that characterise long-term activity signals using a single static complexity metric. The complexity of a Chronic Fatigue Syndrome patient's physical activity signal does not suffice to characterise their high-level functioning over time and has limited potential as an objective monitoring metric by itself.

Subpar reporting of pre-analytical variables in RNA-focused blood plasma studies

Extracellular RNA (cell-free RNA; exRNA) from blood-derived liquid biopsies is an appealing, minimally invasive source of disease biomarkers. As pre-analytical variables strongly influence exRNA measurements, their reporting is essential for meaningful interpretation and replication of results. The aim of this review was to chart to what extent pre-analytical variables are documented, to pinpoint shortcomings and to improve future reporting. In total, 200 blood plasma exRNA studies published in 2018 or 2023 were reviewed for annotation of 22 variables associated with blood collection, plasma preparation, and RNA purification. Our results show that pre-analytical variables are poorly documented, with only three out of 22 variables described in over half of the publications. The percentage of variables reported ranged from 4.6% to 54.6% (mean 24.84%) in 2023 and from 4.6% to 57.1% (mean 28.60%) in 2018. Recommendations and guidelines (i.e., BRISQ, ASCO-CAP, BloodPAC, PPMPT, and CEN standards) have currently not resulted in improved reporting. In conclusion, our results highlight the lack of reporting pre-analytical variables in exRNA studies and advocate for a consistent use of available standards, endorsed by funders and journals.

DLC1 promotes mechanotransductive feedback for YAP via RhoGAP-mediated focal adhesion turnover

Angiogenesis is a tightly controlled dynamic process demanding a delicate equilibrium between pro-angiogenic signals and factors that promote vascular stability. The spatiotemporal activation of the transcriptional co-factors YAP/TAZ is crucial to allow for efficient collective endothelial migration in angiogenesis. The focal adhesion protein Deleted-in-liver-cancer-1 (DLC1) was recently described as a transcriptional downstream target of YAP/TAZ in endothelial cells. In this study, we uncover a negative feedback loop between DLC1 expression and YAP activity during collective migration and sprouting angiogenesis. In particular, our study demonstrates that signaling via the RhoGAP domain of DLC1 reduces YAP's nuclear localization and its transcriptional activity. Moreover, the RhoGAP activity of DLC1 is essential for YAP-mediated cellular processes, including the regulation of focal adhesion turnover, traction forces, and sprouting angiogenesis. We show that DLC1 restricts intracellular cytoskeletal tension by inhibiting Rho signaling at the basal adhesion plane, consequently reducing nuclear YAP localization. Collectively, these findings underscore the significance of DLC1 expression levels and its function in mitigating intracellular tension as a pivotal mechanotransductive feedback mechanism that finely tunes YAP activity throughout the process of sprouting angiogenesis.

Cell-free DNA methylation-based preeclampsia prediction: A journey to improve maternal health

Presymptomatic prediction of preeclampsia (PE) is crucial to enable early prophylactic treatment. Current screening tools are either complex or lack predictive value. We recently demonstrated that cell-free DNA methylation can be leveraged to predict early-onset PE in 57% at a 10% false positive rate. Importantly, this minimally invasive screening test can be implemented as an add-on to current widespread noninvasive prenatal aneuploidy screening. Here, we highlight the pitfalls and promising prospects of this research.

Bottom-Up Extrusion-Based Biofabrication of the Osteoid Niche

Bone regeneration remains a clinical challenge given the transplantation incidence rate and the associated economic burden. Bottom-up osteoid tissue engineering has the potential to offer an alternative approach to current clinical solutions that suffer from various drawbacks. In this paper, deposition-based bioprinting is exploited while the effect is explored of both the crosslinking mechanism (gelatin methacryloyl (GelMA) versus gelatin norbornene (DS 91) crosslinked with thiolated gelatin (GelNBSH)) and the degree of substitution (GelNBSH versus norbornene-norbornene-modified gelatin (DS 169) crosslinked with thiolated gelatin (GelNBNBSH)) on the presented biophysical cues as well as on the osteogenic differentiation. The incorporation of tris(2-carboxyethyl)phosphine (TCEP) to the step-growth inks allows the production of reproducible and biocompatible scaffolds based on thiol-ene chemistry. Dental pulp stem cell encapsulation in GelNBNBSH biofabricated constructs shows a favorable response due to the combination of its stress relaxation and substrate rigidity (bulk compressive modulus of 11-30 kPa) as reflected by a sevenfold increase in calcium production compared to the tissue engineering standard GelMA. This work is the first to exploit a controlled biocompatible and cell-interactive thiolated macromolecular crosslinker (GelSH + TCEP) allowing the extrusion-based biofabrication of low concentration (5 w/v%) modified osteogenic gelatin-based inks (GelNBNBSH + TCEP).

Developmental epileptic encephalopathy in DLG4-related synaptopathy

OBJECTIVE

The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy.

METHODS

We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician.

RESULTS

A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants.

SIGNIFICANCE

Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

In vitro cannabinoid receptor activity, metabolism, and detection in seized samples of CH-PIATA, a new indole-3-acetamide synthetic cannabinoid

The rapidly evolving synthetic cannabinoid receptor agonist (SCRA) market poses significant challenges for forensic scientists. Since the enactment of a generic ban in China, a variety of new compounds have emerged capable of evading the legislation by carrying new structural features. One recent example of a SCRA with new linker and head moieties is CH-PIATA (CH-PIACA, CHX-PIATA, CHX-PIACA). CH-PIATA bears an additional methylene spacer in the linker moiety between the indole core and the traditional carbonyl component of the linker. This study describes detections in 2022 of this new SCRA in the United States, Belgium, and Scottish prisons. CH-PIATA was detected once in a seized powder by Belgian customs and 12 times in Scottish prisons in infused papers or resin. The metabolites of CH-PIATA were investigated via in vitro human liver microsome (HLM) incubations and eight metabolites were identified, dominated by oxidative biotransformations. A blood sample from the United States was confirmed to contain a mixture of SCRAs including CH-PIATA via presence of the parent and at least five of the metabolites identified from HLM incubations. Furthermore, this paper evaluates the intrinsic in vitro cannabinoid 1 and 2 (CB1 and CB2) receptor activation potential of CH-PIATA reference material and the powder seized by Belgian customs by means of β-arrestin 2 recruitment assays. Both the reference and the seized powder showed a weak activity at both CB receptors with signs of antagonism found. Based on these results, the expected harm potential of this newly emerging substance remains limited.

Does parents' perceived style of setting limits to gaming matter? The interplay between profiles of parental mediation and BIS/BAS sensitivity in problematic gaming and online gambling

INTRODUCTION

Parents try to prevent possible negative outcomes associated with gaming by setting rules on their adolescent's gaming behavior (i.e., restrictive mediation). Parents can use either more autonomy-supportive or more controlling styles to communicate those rules. Using a person-centered approach, this study aims to, first, identify profiles of parents' perceived degree of restrictive mediation in gaming and styles of communicating these rules (i.e., autonomy-supportive and controlling); second, to examine how adolescents in different profiles differ in terms of maladaptive gaming outcomes (i.e., problematic gaming, simulated, and online gambling); third, to investigate the moderating role of gaming frequency and adolescents' personality (i.e., behavioral inhibition system [BIS] sensitivity and behavioral activation system [BAS] sensitivity) in the associations between the parental profiles and the outcomes.

METHODS

The study used quantitative, cross-sectional survey data from Belgian adolescents (N = 1651, mean age = 14.00 years, 51.2% boys), collected between November 2021 and February 2022 in schools.

RESULTS

Cluster analysis yielded four profiles of perceived restrictive mediation: an exclusively controlling one, an autonomy-supportive one, one where parents used a perceived mix of both communication styles, and one where there was an overall perceived lack of restrictive mediation. Adolescents in the controlling profile displayed the most maladaptive outcomes. Some of the associations between the parental profiles and the outcomes were stronger for more frequent gamers and for adolescents scoring higher on both BIS and BAS sensitivity.

CONCLUSION

Associations between the parental profiles and gaming outcomes were theoretically meaningful, yet small in terms of effect size.

Transcriptional chronology reveals conserved genes involved in pennate diatom sexual reproduction

Sexual reproduction is a major driver of adaptation and speciation in eukaryotes. In diatoms, siliceous microalgae with a unique cell size reduction-restitution life cycle and among the world's most prolific primary producers, sex also acts as the main mechanism for cell size restoration through the formation of an expanding auxospore. However, the molecular regulators of the different stages of sexual reproduction and size restoration are poorly explored. Here, we combined RNA sequencing with the assembly of a 55 Mbp reference genome for Cylindrotheca closterium to identify patterns of gene expression during different stages of sexual reproduction. These were compared with a corresponding transcriptomic time series of Seminavis robusta to assess the degree of expression conservation. Integrative orthology analysis revealed 138 one-to-one orthologues that are upregulated during sex in both species, among which 56 genes consistently upregulated during cell pairing and gametogenesis, and 11 genes induced when auxospores are present. Several early, sex-specific transcription factors and B-type cyclins were also upregulated during sex in other pennate and centric diatoms, pointing towards a conserved core regulatory machinery for meiosis and gametogenesis across diatoms. Furthermore, we find molecular evidence that the pheromone-induced cell cycle arrest is short-lived in benthic diatoms, which may be linked to their active mode of mate finding through gliding. Finally, we exploit the temporal resolution of our comparative analysis to report the first marker genes for auxospore identity called AAE1-3 ("Auxospore-Associated Expression"). Altogether, we introduce a multi-species model of the transcriptional dynamics during size restoration in diatoms and highlight conserved gene expression dynamics during different stages of sexual reproduction.

Adolescents' mental health in the social-media era: The role of offline and online need-based experiences

INTRODUCTION

Debate about the precise role of social media use (SMU) in the mental health of today's adolescents is still ongoing. The present study adds to the literature by focusing on adolescents' experiences during SMU and in their offline activities through the lens of basic psychological needs, which are central to self-determination theory.

METHODS

To examine the joint and supplementary effects of need-experiences in the offline and SMU domain (i.e., SMU satisfaction, offline satisfaction, SMU frustration, offline frustration) on several indicators of adolescents' mental health (i.e., vitality, life satisfaction, sleep quality, anxiety, and depression), polynomial regression analyses were used. Three cross-sectional samples were collected in Belgium, including early to mid-adolescents during the COVID-pandemic (Sample 1; N = 447; Mage = 14.26; 54.4% female) as well as postpandemic (Sample 2; N = 179, Mage = 15.25; 54.2% female), and among college students in postpandemic times (Sample 3; N = 4977; Mage = 20.72; 69.1% female).

RESULTS

The results showed that need-experiences common to both domains were a robust factor associated with mental health. This finding was obtained across all samples and outcomes, with need satisfaction playing a beneficial and need frustration a harmful role. We further found that offline need-experiences serve as a more crucial predictor of adolescents' mental health than need experiences on social media.

CONCLUSIONS

Adolescents' experiences of need satisfaction and need frustration on social media and in offline activities are central to their mental health. However, only relying on SMU as a single source of need satisfaction may not be recommended, given that offline experiences seem to be more decisive.

French Polynesian Scytosiphonaceae (Ectocarpales, Phaeophyceae): A combined molecular and morphological approach to their diversity and systematics

This study revisited the taxonomy and diversity of brown macroalgae within the Scytosiphonaceae family in French Polynesia, which had previously been recognized as encompassing only six species. Using the chloroplast and mitochondrial genes rbcL, psbA, and cox3 as molecular markers in conjunction with morpho-anatomical observations, we unveiled the presence of 11 species spanning six genera: Chnoospora minima, Colpomenia claytoniae, Co. sinuosa [groups IIIa and IIIb], Hydroclathrus rapanuii, H. tenuis, H. tilesii, Manzaea minuta, Pseudochnoospora implexa, Rosenvingea australis, and the newly described species R. polynesiensis sp. nov. and R. tahitiensis sp. nov. This encompasses the recognition of two previously unreported genera in this region: Manzaea and Pseudochnoospora. Sequences were successfully acquired for four taxa that had been documented previously, while the absence of sequences for H. clathratus and H. tumulis in French Polynesia raises queries about their presence in this region. With these additions, the total species count now stands at 13 (including H. clathratus and H. tumulis), one being an endemic species. The molecular-assisted alpha taxonomic approach used here allowed for a critical revision of the Scytosiphonaceae species checklist for French Polynesia. The diversity revealed in this region accounts for a substantial 20% of the family's global diversity. Additionally, our study presents an updated species-level phylogeny for the Scytosiphonaceae.

Serum methylmalonic acid concentrations at breast cancer diagnosis significantly correlate with clinical frailty

Methylmalonic acid (MMA), a by-product of propionate metabolism, is known to increase with age. This study investigates the potential of serum MMA concentrations as a biomarker for age-related clinical frailty in older patients with breast cancer. One hundred nineteen patients ≥ 70 years old with early-stage breast cancer were included (median age 76 years). G8 screening, full geriatric assessment, clinical parameters (i.e., estimated glomerular filtration rate (eGFR) and body mass index (BMI)), and serum sample collection were collected at breast cancer diagnosis before any therapy was administered. MMA concentrations were measured via liquid chromatography with tandem mass spectrometry. MMA concentrations significantly increased with age and eGFR (all P < 0.001) in this older population. The group with an abnormal G8 (≤ 14, 51% of patients) had significantly higher MMA levels than the group with normal G8 (> 14, 49%): 260 nmol/L vs. 188 nmol/L, respectively (P = 0.0004), even after correcting for age and eGFR (P = 0.001). Furthermore, in the detailed assessment, MMA concentrations correlated most with mobility (Eastern Cooperative Oncology Group (ECOG) Performance Status and Activities of Daily Living (ADL) tools, all P ≤ 0.02), comorbidity (Charlson Comorbidity Index (CCI) tool, P = 0.005), and polypharmacy (P < 0.001), whereas no significant associations were noted for instrumental ADL (IADL), Mini-Mental State Examination (MMSE), Geriatric Depression Scale-15 (GDS15), Mini Nutritional Assessment-Short Form (MNA-SF), and pain (all P > 0.1). In addition, our results showed that higher MMA levels correlate with poor overall survival in breast cancer patients (P = 0.003). Elevated serum MMA concentrations at initial diagnosis are significantly associated, not only with age but also independently with clinical frailty, suggesting a possible influence of MMA on clinical frailty in older patients with early-stage breast cancer.

Integrated gut metabolome and microbiome fingerprinting reveals that dysbiosis precedes allergic inflammation in IgE-mediated pediatric cow's milk allergy

BACKGROUND

IgE-mediated cow's milk allergy (IgE-CMA) is one of the first allergies to arise in early childhood and may result from exposure to various milk allergens, of which β-lactoglobulin (BLG) and casein are the most important. Understanding the underlying mechanisms behind IgE-CMA is imperative for the discovery of novel biomarkers and the design of innovative treatment and prevention strategies.

METHODS

We report a longitudinal in vivo murine model, in which two mice strains (BALB/c and C57Bl/6) were sensitized to BLG using either cholera toxin or an oil emulsion (n = 6 per group). After sensitization, mice were challenged orally, their clinical signs monitored, antibody (IgE and IgG1) and cytokine levels (IL-4 and IFN-γ) measured, and fecal samples subjected to metabolomics. The results of the murine models were further extrapolated to fecal microbiome-metabolome data from our population of IgE-CMA (n = 22) and healthy (n = 23) children (Trial: NCT04249973), on which polar metabolomics, lipidomics and 16S rRNA metasequencing were performed. In vitro gastrointestinal digestions and multi-omics corroborated the microbial origin of proposed metabolic changes.

RESULTS

During mice sensitization, we observed multiple microbially derived metabolic alterations, most importantly bile acid, energy and tryptophan metabolites, that preceded allergic inflammation. We confirmed microbial dysbiosis, and its associated effect on metabolic alterations in our patient cohort, through in vitro digestions and multi-omics, which was accompanied by metabolic signatures of low-grade inflammation.

CONCLUSION

Our results indicate that gut dysbiosis precedes allergic inflammation and nurtures a chronic low-grade inflammation in children on elimination diets, opening important new opportunities for future prevention and treatment strategies.

Serological diagnosis of soil-transmitted helminth (Ascaris, Trichuris and hookworm) infections: A scoping review

BACKGROUND

The World Health Organization emphasizes the importance of integrated monitoring and evaluation in neglected tropical disease (NTD) control programs. Serological assays offer a potential solution for integrated diagnosis of NTDs, particularly for those requiring mass drug administration (MDA) as primary control and elimination strategy. This scoping review aims (i) to provide an overview of assays using serum or plasma to detect infections with soil-transmitted helminths (STHs) in both humans and animals, (ii) to examine the methodologies used in this research field and (iii) to discuss advancements in serological diagnosis of STHs to guide prevention and control programs in veterinary and human medicine.

METHODOLOGY

We conducted a systematic search in the Ovid MEDLINE, Embase and Cochrane Library databases, supplemented by a Google search using predefined keywords to identify commercially available serological assays. Additionally, we performed a patent search through Espacenet.

PRINCIPAL FINDINGS

We identified 85 relevant literature records spanning over 50 years, with a notable increased interest in serological assay development in recent years. Most of the research efforts concentrated on diagnosing Ascaris infections in both humans and pigs, primarily using ELISA and western blot technologies. Almost all records targeted antibodies as analytes, employing proteins and peptides as analyte detection agents. Approximately 60% of sample sets described pertained to human samples. No commercially available tests for Trichuris or hookworms were identified, while for Ascaris, there are at least seven different ELISAs on the market.

CONCLUSIONS

While a substantial number of assays are employed in epidemiological research, the current state of serological diagnosis for guiding STH prevention and control programs is limited. Only two assays designed for pigs are used to inform efficient deworming practices in pig populations. Regarding human diagnosis, none of the existing assays has undergone extensive large-scale validation or integration into routine diagnostics for MDA programs.

Frequency-Following Responses in Sensorineural Hearing Loss: A Systematic Review

PURPOSE

This systematic review aims to assess the impact of sensorineural hearing loss (SNHL) on various frequency-following response (FFR) parameters.

METHODS

Following PRISMA guidelines, a systematic review was conducted using PubMed, Web of Science, and Scopus databases up to January 2023. Studies evaluating FFRs in patients with SNHL and normal hearing controls were included.

RESULTS

Sixteen case-control studies were included, revealing variability in acquisition parameters. In the time domain, patients with SNHL exhibited prolonged latencies. The specific waves that were prolonged differed across studies. There was no consensus regarding wave amplitude in the time domain. In the frequency domain, focusing on studies that elicited FFRs with stimuli of 170 ms or longer, participants with SNHL displayed a significantly smaller fundamental frequency (F0). Results regarding changes in the temporal fine structure (TFS) were inconsistent.

CONCLUSION

Patients with SNHL may require more time for processing (speech) stimuli, reflected in prolonged latencies. However, the exact timing of this delay remains unclear. Additionally, when presenting longer stimuli (≥ 170 ms), patients with SNHL show difficulties tracking the F0 of (speech) stimuli. No definite conclusions could be drawn on changes in wave amplitude in the time domain and the TFS in the frequency domain. Patient characteristics, acquisition parameters, and FFR outcome parameters differed greatly across studies. Future studies should be performed in larger and carefully matched subject groups, using longer stimuli presented at the same intensity in dB HL for both groups, or at a carefully determined maximum comfortable loudness level.

Cable bacteria delay euxinia and modulate phosphorus release in coastal hypoxic systems

Cable bacteria are long, filamentous bacteria with a unique metabolism involving centimetre-scale electron transport. They are widespread in the sediment of seasonally hypoxic systems and their metabolic activity stimulates the dissolution of iron sulfides (FeS), releasing large quantities of ferrous iron (Fe2+) into the pore water. Upon contact with oxygen, Fe2+ oxidation forms a layer of iron(oxyhydr)oxides (FeOx), which in its turn can oxidize free sulfide (H2S) and trap phosphorus (P) diffusing upward. The metabolism of cable bacteria could thus prevent the release of H2S from the sediment and reduce the risk of euxinia, while at the same time modulating P release over seasonal timescales. However, experimental support for this so-called 'iron firewall hypothesis' is scarce. Here, we collected natural sediment in a seasonally hypoxic basin in three different seasons. Undisturbed sediment cores were incubated under anoxic conditions and the effluxes of H2S, dissolved iron (dFe) and phosphate (PO4 3-) were monitored for up to 140 days. Cores with recent cable bacterial activity revealed a high stock of sedimentary FeOx, which delayed the efflux of H2S for up to 102 days. Our results demonstrate that the iron firewall mechanism could exert an important control on the prevalence of euxinia and regulate the P release in coastal oceans.

Growth and remodeling of the dissected membrane in an idealized dissected aorta model

While transitioning from the acute to chronic phase, the wall of a dissected aorta often expands in diameter and adaptations in thickness and microstructure take place in the dissected membrane. Including the mechanisms, leading to these changes, in a computational model is expected to improve the accuracy of predictions of the long-term complications and optimal treatment timing of dissection patients. An idealized dissected wall was modeled to represent the elastin and collagen production and/or degradation imposed by stress- and inflammation-mediated growth and remodeling, using the homogenized constrained mixture theory. As no optimal growth and remodeling parameters have been defined for aortic dissections, a Latin hypercube sampling with 1000 parameter combinations was assessed for four inflammation patterns, with a varying spatial extent (full/local) and temporal evolution (permanent/transient). The dissected membrane thickening and microstructure was considered together with the diameter expansion over a period of 90 days. The highest success rate was found for the transient inflammation patterns, with about 15% of the samples leading to converged solutions after 90 days. Clinically observed thickening rates were found for 2-4% of the transient inflammation samples, which represented median total diameter expansion rates of about 5 mm/year. The dissected membrane microstructure showed an elastin decrease and, in most cases, a collagen increase. In conclusion, the model with the transient inflammation pattern allowed the reproduction of clinically observed dissected membrane thickening rates, diameter expansion rates and adaptations in microstructure, thus providing guidance in reducing the parameter space in growth and remodeling models of aortic dissections.

Longitudinal trajectory of medial gastrocnemius muscle growth in the first years of life

AIM

To define the longitudinal trajectory of gastrocnemius muscle growth in 6- to 36-month-old children with and without spastic cerebral palsy (SCP) and to compare trajectories by levels of gross motor function (Gross Motor Function Classification System, GMFCS) and presumed brain-lesion timing.

METHOD

Twenty typically developing children and 24 children with SCP (GMFCS levels I-II/III-IV = 15/9), were included (28/16 females/males; mean age at first scan 15.4 months [standard deviation 4.93, range 6.24-23.8]). Three-dimensional freehand ultrasound was used to repeatedly assess muscle volume, length, and cross-sectional area (CSA), resulting in 138 assessments (mean interval 7.9 months). Brain lesion timing was evaluated with magnetic resonance imaging classification. Linear mixed-effects models defined growth rates, adjusted for GMFCS levels and presumed brain-lesion timing.

RESULTS

At age 12 months, children with SCP showed smaller morphological muscle size than typically developing children (5.8 mL vs 9.8 mL, p < 0.001), while subsequently no differences in muscle growth were found between children with and without SCP (muscle volume: 0.65 mL/month vs 0.74 mL/month). However, muscle volume and CSA growth rates were lower in children classified in GMFCS levels III and IV than typically developing children and those classified in GMFCS levels I and II, with differences ranging from -56% to -70% (p < 0.001).

INTERPRETATION

Muscle growth is already hampered during infancy in SCP. Muscle size growth further reduces with decreasing functional levels, independently from the brain lesion. Early monitoring of muscle growth combined with early intervention is needed.

Peer Influences on (Dis)Engagement in Early Adolescence: the Role of Friendship, Social Status, and Academic Status

Academic engagement in adolescence is shaped by influences from the peer environment, yet the types of peers impacting engagement remain unclear. This study explores the roles of friends, popular students, and intelligent students in shaping peers' behavioral and emotional (dis)engagement. Data were analyzed from 3409 Flemish eighth-grade students (Mage = 13.48 years, SD = 0.46, 50.09% female), utilizing self-reports and peer nominations to measure (dis)engagement and map friendship, popularity, and intelligence networks in the fall and spring. Longitudinal network analysis revealed that, while accounting for selection and network structure, friends influenced all dimensions of engagement. Popular students influenced emotional disengagement, and intelligent students impacted emotional engagement. These findings underscore the intricate nature of peer dynamics, highlighting the need for a multidimensional approach to studying peer influences on engagement.

Machine learning-based peptide-spectrum match rescoring opens up the immunopeptidome

Immunopeptidomics is a key technology in the discovery of targets for immunotherapy and vaccine development. However, identifying immunopeptides remains challenging due to their non-tryptic nature, which results in distinct spectral characteristics. Moreover, the absence of strict digestion rules leads to extensive search spaces, further amplified by the incorporation of somatic mutations, pathogen genomes, unannotated open reading frames, and post-translational modifications. This inflation in search space leads to an increase in random high-scoring matches, resulting in fewer identifications at a given false discovery rate. Peptide-spectrum match rescoring has emerged as a machine learning-based solution to address challenges in mass spectrometry-based immunopeptidomics data analysis. It involves post-processing unfiltered spectrum annotations to better distinguish between correct and incorrect peptide-spectrum matches. Recently, features based on predicted peptidoform properties, including fragment ion intensities, retention time, and collisional cross section, have been used to improve the accuracy and sensitivity of immunopeptide identification. In this review, we describe the diverse bioinformatics pipelines that are currently available for peptide-spectrum match rescoring and discuss how they can be used for the analysis of immunopeptidomics data. Finally, we provide insights into current and future machine learning solutions to boost immunopeptide identification.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

Facile Fabrication of Flexible and High-Performing Thermoelectrics by Direct Laser Printing on Plastic Foil

The emerging fields of wearables and the Internet of Things introduce the need for electronics and power sources with unconventional form factors: large area, customizable shape, and flexibility. Thermoelectric (TE) generators can power those systems by converting abundant waste heat into electricity, whereas the versatility of additive manufacturing suits heterogeneous form factors. Here, additive manufacturing of high-performing flexible TEs is proposed. Maskless and large-area patterning of Bi2Te3-based films is performed by laser powder bed fusion directly on plastic foil. Mechanical interlocking allows simultaneous patterning, sintering, and attachment of the films to the substrate without using organic binders that jeopardize the final performance. Material waste could be minimized by recycling the unexposed powder. The particular microstructure of the laser-printed material renders the-otherwise brittle-Bi2Te3 films highly flexible despite their high thickness. The films survive 500 extreme-bending cycles to a 0.76 mm radius. Power factors above 1500 µW m-1K-2 and a record-low sheet resistance for flexible TEs of 0.4 Ω sq-1 are achieved, leading to unprecedented potential for power generation. This versatile fabrication route enables innovative implementations, such as cuttable arrays adapting to specific applications in self-powered sensing, and energy harvesting from unusual scenarios like human skin and curved hot surfaces.