Dynamic intracellular exchange of nanomaterials' protein corona perturbs proteostasis and remodels cell metabolism.

The nanomaterial­protein "corona" is a dynamic entity providing a synthetic­natural interface mediating cellular uptake and subcellular distribution of nanomaterials in biological systems. As nanomaterials are central to the safe-by-design of future nanomedicines and the practice of nanosafety, understanding and delineating the biological and toxicological signatures of the ubiquitous nanomaterial­protein corona are precursors to the continued development of nano­bio science and engineering. However, despite well over a decade of extensive research, the dynamics of intracellular release or exchange of the blood protein corona from nanomaterials following their cellular internalization remains unclear, and the biological footprints of the nanoparticle­protein corona traversing cellular compartments are even less well understood. To address this crucial bottleneck, the current work screened evolution of the intracellular protein corona along the endocytotic pathway from blood via lysosomes to cytoplasm in cancer cells. Intercellular proteins, including pyruvate kinase M2 (PKM2), and chaperones, displaced some of the initially adsorbed blood proteins from the nanoparticle surface, which perturbed proteostasis and subsequently incited chaperone-mediated autophagy (CMA) to disrupt the key cellular metabolism pathway, including glycolysis and lipid metabolism. Since proteostasis is key to the sustainability of cell function, its collapse and the resulting CMA overdrive spell subsequent cell death and aging. Our findings shed light on the consequences of the transport of extracellular proteins by nanoparticles on cell metabolism.

A Systematic Literature Review on the Use of Dried Biofluid Microsampling in Patients With Kidney Disease.

BACKGROUND: Kidney disease is fairly unique due to the lack of symptoms associated with disease activity, and it is therefore dependent on biological monitoring. Dried biofluids, particularly dried capillary blood spots, are an accessible, easy-to-use technology that have seen increased utility in basic science research over the past decade. However, their use is yet to reach the kidney patient population clinically or in large-scale discovery science initiatives. The aim of this study was to systematically evaluate the existing literature surrounding the use of dried biofluids in kidney research. METHODS: A systematic literature review was conducted using three search engines and a predefined search term strategy. Results were summarised according to the collection method, type of biofluid, application to kidney disease, cost, sample stability and patient acceptability. RESULTS: In total, 404 studies were identified and 67 were eligible. In total, 34,739 patients were recruited to these studies with a skew towards male participants (> 73%). The majority of samples were blood, which was used either for monitoring anti-rejection immunosuppressive drug concentrations or for kidney function. Dried biofluids offered significant cost savings to the patient and healthcare service. The majority of patients preferred home microsampling when compared to conventional monitoring. CONCLUSION: There is an unmet need in bringing dried microsampling technology to advance kidney disease despite its advantages. This technology provides an opportunity to upscale patient recruitment and longitudinal sampling, enhance vein preservation and overcome participation bias in research.

Biotransformation modulates the penetration of metallic nanomaterials across an artificial blood-brain barrier model.

Understanding the potential of nanomaterials (NMs) to cross the blood-brain barrier (BBB), as a function of their physicochemical properties and subsequent behavior, fate, and adverse effect beyond that point, is vital for evaluating the neurological effects arising from their unintentional entry into the brain, which is yet to be fully explored. This is not only due to the complex nature of the brain but also the existing analytical limitations for characterization and quantification of NMs in the complex brain environment. By using a fit-for-purpose analytical workflow and an in vitro BBB model, we show that the physiochemical properties of metallic NMs influence their biotransformation in biological matrices, which in turn modulates the transport form, efficiency, amounts, and pathways of NMs through the BBB and, consequently, their neurotoxicity. The data presented here will support in silico modeling and prediction of the neurotoxicity of NMs and facilitate the tailored design of safe NMs.

The readability of parent information leaflets in paediatric studies.

BACKGROUND: Poor literacy can impact achieving optimal health outcomes. The aim of this project was to assess the readability of parent information leaflets (PILs). METHODS: A single-centre study using paediatric PILs. Five readability tests were applied (Gunning Fog Index (GFI), Simple Measure of Gobbledygook (SMOG), Flesch Kincaid Grade Level (FKGL), Coleman-Liau Index (CLI) and Automated Readability Index (ARI)). Results were compared to standards and by subtype. RESULTS: A total of 109 PILs were obtained; mean (±SD) number of characters was 14,365 (±12,055), total words 3066 (±2541), number of sentences 153 (±112), lexical density 49 (±3), number of characters per word 4.7 (±0.1), number of syllables per word 1.6 (±0.1) and number of words per sentence 19.1 (±2.5). The Flesch reading ease score was 51.1 (±5.6), equating to reading age 16-17 years. The mean PIL readability scores were GFI (12.18), SMOG (11.94), FKGL (10.89), CLI (10.08) and ARI (10.1). There were 0 (0%) PILs classed as easy (score <6), 21 (19%) mid-range (6-10) and 88 (81%) were difficult (>10). They were significantly above the recommended reading age (p < 0.0001) and commercial studies were least accessible (p < 0.01). CONCLUSION: Existing PILs are above the national reading level. Researchers should use readability tools to ensure that they are accessible. IMPACT: Poor literacy is a barrier to accessing research and achieving good health outcomes. Current parent information leaflets are pitched far higher than the national reading age. This study provides data to demonstrate the reading age of a large portfolio of research studies. This work raises awareness of literacy as a barrier to research participation and provides tips on how to improve the readability of patient information leaflets to guide investigators.

Increased Urinary IgA in Paediatric IgA Vasculitis Nephritis.

IgA vasculitis (IgAV) is the most common form of paediatric vasculitis, with up to 50% of patients experiencing kidney inflammation. Much remains unknown about IgAV, but it is believed to arise due to galactose-deficient IgA1 promoting an auto-inflammatory response. This study assesses whether urinary IgA can be detected in children with IgAV to allow further evaluation of IgA1 and whether it has any relationship with nephritis. Urinary and serum IgA concentrations were measured using commercially available ELISA kits. Patients were grouped into IgAV nephritis (IgAVN) or IgAV without nephritis (IgAVwoN). Fifty-nine children were included: IgAVN n = 12, IgAVwoN n = 35, and healthy controls (HC) n = 12, with a mean age of 8.2 ± 4.1 years. Urinary IgA concentrations were statistically significantly higher in patients with IgAV (107.1 ± 136.3 µg/mmol) compared to HC (50.6 ± 26.3 µg/mmol; p = 0.027) and IgAVN (229.8 ± 226.3 µg/mmol) compared to both IgAVwoN (65.0 ± 37.8 µg/mmol; p = 0.002) and HC (p < 0.001). Urinary IgA concentrations were able to distinguish between renal status (AUC 0.838, 95%CI [0.704−0.973], p < 0.001) and did not correlate with proteinuria (r = 0.124; p = 0.407). Urinary IgA concentrations are increased in children with IgAVN, and it has the potential to act as a non-invasive biofluid to further evaluate nephritis in this disease.

An Untargeted Thermogravimetric Analysis-Fourier Transform Infrared-Gas Chromatography-Mass Spectrometry Approach for Plastic Polymer Identification.

Reliable chemical identification of specific polymers in environmental samples represents a major challenge in plastic research, especially with the wide range of commercial polymers available, along with variable additive mixtures. Thermogravimetric analysis-Fourier transform infrared-gas chromatography-mass spectrometry (TGA-FTIR-GC-MS) offers a unique characterization platform that provides both physical and chemical properties of the analyzed polymers. This study presents a library of 11 polymers generated using virgin plastics and post-consumer products. TGA inflection points and mass of remaining residues following pyrolysis, in some cases, proved to be indicative of the polymer type. FTIR analysis of the evolved gas was able to differentiate between all but polypropylene (PP) and polyethylene (PE). Finally, GC-MS was able to differentiate between the unique chemical fingerprints of all but one polymer in the library. This library was then used to characterize real environmental samples of mesoplastics collected from beaches in the U.K. and South Africa. Unambiguous identification of the polymer types was achieved, with PE being the most frequently detected polymer and with South African samples indicating variations that potentially resulted from aging and weathering.

Capillary Electrophoresis-Mass Spectrometry at Trial by Metabo-Ring: Effective Electrophoretic Mobility for Reproducible and Robust Compound Annotation.

Capillary zone electrophoresis-mass spectrometry (CE-MS) is a mature analytical tool for the efficient profiling of (highly) polar and ionizable compounds. However, the use of CE-MS in comparison to other separation techniques remains underrepresented in metabolomics, as this analytical approach is still perceived as technically challenging and less reproducible, notably for migration time. The latter is key for a reliable comparison of metabolic profiles and for unknown biomarker identification that is complementary to high resolution MS/MS. In this work, we present the results of a Metabo-ring trial involving 16 CE-MS platforms among 13 different laboratories spanning two continents. The goal was to assess the reproducibility and identification capability of CE-MS by employing effective electrophoretic mobility (µeff) as the key parameter in comparison to the relative migration time (RMT) approach. For this purpose, a representative cationic metabolite mixture in water, pretreated human plasma, and urine samples spiked with the same metabolite mixture were used and distributed for analysis by all laboratories. The µeff was determined for all metabolites spiked into each sample. The background electrolyte (BGE) was prepared and employed by each participating lab following the same protocol. All other parameters (capillary, interface, injection volume, voltage ramp, temperature, capillary conditioning, and rinsing procedure, etc.) were left to the discretion of the contributing laboratories. The results revealed that the reproducibility of the µeff for 20 out of the 21 model compounds was below 3.1% vs 10.9% for RMT, regardless of the huge heterogeneity in experimental conditions and platforms across the 13 laboratories. Overall, this Metabo-ring trial demonstrated that CE-MS is a viable and reproducible approach for metabolomics.

The Nanomaterial Metabolite Corona Determined Using a Quantitative Metabolomics Approach: A Pilot Study.

Nanomaterials (NMs) are promptly coated with biomolecules in biological systems leading to the formation of the so-called corona. To date, research has predominantly focused on the protein corona and how it affects NM uptake, distribution, and bioactivity by conferring a biological identity to NMs enabling interactions with receptors to mediate cellular responses. Thus, protein corona studies are now integral to nanosafety assessment. However, a larger class of molecules, the metabolites, which are orders of magnitude smaller than proteins (<1000 Da) and regulate metabolic pathways, has been largely overlooked. This hampers the understanding of the bio-nano interface, development of computational predictions of corona formation, and investigations into uptake or toxicity at the cellular level, including identification of molecular initiating events triggering adverse outcome pathways. Here, a capillary electrophoresis-mass spectrometry based metabolomics approach reveals that pure polar ionogenic metabolite standards differentially adsorb to a range of 6 NMs (SiO2 , 3 TiO2 with different surface chemistries, and naïve and carboxylated polystyrene NMs). The metabolite corona composition is quantitatively compared using protein-free and complete plasma samples, revealing that proteins in samples significantly change the composition of the metabolite corona. This key finding provides the basis to include the metabolite corona in future nanosafety endeavors.

Metabolic characterisation of disturbances in the APOC3/triglyceride-rich lipoprotein pathway through sample-based recall by genotype.

INTRODUCTION: High plasma triacylglyceride levels are known to be associated with increased risk of atherosclerotic cardiovascular disease. Apolipoprotein C-III (apoC-III) is a key regulator of plasma triacylglyceride levels and is associated with hypertriglyceridemia via a number of pathways. There is consistent evidence for an association of cardiovascular events with blood apoC-III level, with support from human genetic studies of APOC3 variants. As such, apoC-III has been recognised as a potential therapeutic target for patients with severe hypertriglyceridaemia with one of the most promising apoC-III-targeting drugs, volanesorsen, having recently progressed through Phase III trials. OBJECTIVES: To exploit a rare loss of function variant in APOC3 (rs138326449) to characterise the potential long-term treatment effects of apoC-III targeting interventions on the metabolome. METHODS: In a recall-by-genotype study, 115 plasma samples were analysed by UHPLC-MS to acquire non-targeted metabolomics data. The study included samples from 57 adolescents and 33 adults. Overall, 12 985 metabolic features were tested for an association with APOC3 genotype. RESULTS: 161 uniquely annotated metabolites were found to be associated with rs138326449(APOC3). The highest proportion of associated metabolites belonged to the acyl-acyl glycerophospholipid and triacylglyceride metabolite classes. In addition to the anticipated (on-target) reduction of metabolites in the triacylglyceride and related classes, carriers of the rare variant exhibited previously unreported increases in levels of a number of metabolites from the acyl-alkyl glycerophospholipid class. CONCLUSION: Overall, our results suggest that therapies targeting apoC-III may potentially achieve a broad shift in lipid profile that favours better metabolic health.

Quantitative Lipoprotein Subclass and Low Molecular Weight Metabolite Analysis in Human Serum and Plasma by 1H NMR Spectroscopy in a Multilaboratory Trial.

We report an extensive 600 MHz NMR trial of quantitative lipoprotein and small-molecule measurements in human blood serum and plasma. Five centers with eleven 600 MHz NMR spectrometers were used to analyze 98 samples including 20 quality controls (QCs), 37 commercially sourced, paired serum and plasma samples, and two National Institute of Science and Technology (NIST) reference material 1951c replicates. Samples were analyzed using rigorous protocols for sample preparation and experimental acquisition. A commercial lipoprotein subclass analysis was used to quantify 105 lipoprotein subclasses and 24 low molecular weight metabolites from the NMR spectra. For all spectrometers, the instrument specific variance in measuring internal QCs was lower than the percentage described by the National Cholesterol Education Program (NCEP) criteria for lipid testing [triglycerides <2.7%; cholesterol <2.8%; low-density lipoprotein (LDL) cholesterol <2.8%; high-density lipoprotein (HDL) cholesterol <2.3%], showing exceptional reproducibility for direct quantitation of lipoproteins in both matrixes. The average relative standard deviations (RSDs) for the 105 lipoprotein parameters in the 11 instruments were 4.6% and 3.9% for the two NIST samples, whereas they were 38% and 40% for the 37 commercially sourced plasmas and sera, respectively, showing negligible analytical compared to biological variation. The coefficient of variance (CV) obtained for the quantification of the small molecules across the 11 spectrometers was below 15% for 20 out of the 24 metabolites analyzed. This study provides further evidence of the suitability of NMR for high-throughput lipoprotein subcomponent analysis and small-molecule quantitation with the exceptional required reproducibility for clinical and other regulatory settings.

msPurity: Automated Evaluation of Precursor Ion Purity for Mass Spectrometry-Based Fragmentation in Metabolomics.

Tandem mass spectrometry (MS/MS or MS2) is a widely used approach for structural annotation and identification of metabolites in complex biological samples. The importance of assessing the contribution of the precursor ion within an isolation window for MS2 experiments has been previously detailed in proteomics, where precursor ion purity influences the quality and accuracy of matching to mass spectral libraries, but to date, there has been little attention to this data-processing technique in metabolomics. Here, we present msPurity, a vendor-independent R package for liquid chromatography (LC) and direct infusion (DI) MS2 that calculates a simple metric to describe the contribution of the selected precursor. The precursor purity metric is calculated as "intensity of a selected precursor divided by the summed intensity of the isolation window". The metric is interpolated at the recorded point of MS2 acquisition using bordering full-scan spectra. Isotopic peaks of the selected precursor can be removed, and low abundance peaks that are believed to have limited contribution to the resulting MS2 spectra are removed. Additionally, the isolation efficiency of the mass spectrometer can be taken into account. The package was applied to Data Dependent Acquisition (DDA)-based MS2 metabolomics data sets derived from three metabolomics data repositories. For the 10 LC-MS2 DDA data sets with > ±1 Da isolation windows, the median precursor purity score ranged from 0.67 to 0.96 (scale = 0 to +1). The R package was also used to assess precursor purity of theoretical isolation windows from LC-MS data sets of differing sample types. The theoretical isolation windows being the same width used for an anticipated DDA experiment (±0.5 Da). The most complex sample had a median precursor purity score of 0.46 for the 64,498 XCMS determined features, in comparison to the less spectrally complex sample that had a purity score of 0.66 for 5071 XCMS features. It has been previously reported in proteomics that a purity score of <0.5 can produce unreliable spectra matching results. With this assumption, we show that for complex samples there will be a large number of metabolites where traditional DDA approaches will struggle to provide reliable annotations or accurate matches to mass spectral libraries.

Collection and Preparation of Clinical Samples for Metabolomics.

A wide range of biofluids (urine, serum, plasma, saliva, etc.) as well as cellular and tissue samples can be collected and investigated in clinical metabolomic studies. The choice of sample is dependent on the clinical question being investigated with biofluids typically studied to identify biomarkers, whereas tissues and primary/immortalised cells are typically studied to investigate mechanisms associated with pathophysiological processes. Methods applied to collect samples, quench metabolism and extract samples differ between sample types from simple collect, dilute and analyse methods for urine to complex washing, quenching and biphasic extraction methods for tissues. The range of sample collection and extraction methods are discussed with sample-specific considerations highlighted. Finally, methods for imaging of cells and tissues and for in vivo metabolomic analysis will also be introduced.

Solid-phase extraction and nanoflow liquid chromatography-nanoelectrospray ionization mass spectrometry for improved global urine metabolomics.

Global urine metabolomics is a rapidly expanding field with the potential to discover biomarkers of disease and exposure. To date, most methods focus on rapid sample preparation, using neat or diluted urine, together with high-throughput analyses, and are poorly suited for detection of low abundance metabolites present in urine samples. In this study, novel methods have been developed to analyze urine by splitless nanoflowUHPLC-nanoESI-TOFMS (nUHPLC-nESI-TOFMS) after preconcentration by solid-phase extraction (SPE), thus enabling significant improvements in analytical sensitivity and coverage of the urinary metabolome. In initial work, urine samples were extracted by both anion and cation exchange mixed-mode polymeric SPE cartridges and qualitatively compared with those using conventional sample preparations using UHPLC-ESI-TOFMS analyses. Compared with neat or diluted urine samples, SPE concentration of urine resulted in detection of additional metabolites including bile acids, lipids, pharmaceuticals, and markers of lifestyle, with little loss of other components of the metabolome. Analyses of SPE preparations by nUHPLC-nESI-TOFMS revealed excellent retention time repeatability with <1% coefficient of variation (CV) for 96% of analyzed peaks. The repeatability of the MS response was <30% CV for >79% of MS features in both negative and positive nESI modes. Compared with UHPLC-ESI-TOFMS, analysis by the nanoplatform enabled detection of signaling molecules important in disease processes including sex steroids, glucocorticoids, eicosanoids, and neurotransmitter metabolites. The significant improvement in sensitivity arising from use of splitless nUHPLC-nESI-TOFMS analyses of SPE-concentrated samples represents a step change in coverage of the urinary metabolome, thereby increasing the potential for biomarker discovery.

Urinary markers of the alternative and lectin complement pathway are increased in IgA vasculitis nephritis.

Background: IgA vasculitis (IgAV) is the most common form of childhood vasculitis. Nephritis (IgAVN) occurs in 50% of patients and 1-2% progress to chronic kidney disease stage 5. The pathophysiology of nephritis remains largely unknown, but recent evidence suggests that the complement system may be involved. The aim of this cross-sectional study was to explore whether there is evidence of alternative and/or lectin complement pathway activation in children with IgAVN. Methods: Children with IgAV were recruited and grouped according to proteinuria: IgAVN or IgAV without nephritis (IgAVwoN). Age and sex-matched healthy controls (HCs) were also recruited. Cross-sectional urine and plasma concentrations of complement factor D (CFD), factor B (CFB), and MBL-associated protease 1 (MASP-1) were performed using commercially available enzyme-linked immunoassays. Results: A total of 50 children were included (IgAVN, n = 15; IgAVwoN, n = 20, HCs, n = 15). The mean age was 8.5 ± 3.7 years old, male:female ratio was 1:1. Urinary CFD and CFB concentrations were statistically significantly increased in children with IgAVN (3.5 ± 5.4 µg/mmol; 25.9 ± 26.5 µg/mmol, respectively) compared to both IgAVwoN (0.4 ± 0.4 µg/mmol, P = 0.002; 9.2 ± 11.5 µg/mmol, P = 0.004) and HCs (0.3 ± 0.2 µg/mmol, P < 0.001; 5.1 ± 6.0 µg/mmol, P < 0.001). No statistically significant difference was reported for the plasma concentrations of CFD and CFB. Urinary MASP-1 concentrations were statistically significantly increased in IgAVN (116.9 ± 116.7 ng/mmol) compared to HCs (41.4 ± 56.1 ng/mmol, P = 0.006) and plasma MASP-1 concentrations were increased in IgAVwoN (254.2 ± 23.3 ng/mL) compared to HCs (233.4 ± 6.6 ng/mL, P = 0.046). Conclusion: There is evidence of complement pathway products in the urine of children with IgAVN that warrants further investigation.

A narrative review of potential drug treatments for nephritis in children with IgA vasculitis (HSP).

Immunoglobulin A (IgA) vasculitis (IgAV, also known as Henoch-Schoenlein purpura, HSP) is the most common vasculitis of childhood. It usually presents with a simple, self-limiting disease course; however, a small subset of patients may develop kidney involvement (IgAV-N) which occurs 4-12 weeks after disease onset and is the biggest contributor to long-term morbidity. Treatment currently targets patients with established kidney involvement; however; there is a desire to work towards early prevention of inflammation during the window of opportunity between disease presentation and onset of significant nephritis. There are no clinical trials evaluating drugs which may prevent or halt the progression of nephritis in children with IgAV apart from the early use of corticosteroids which have no benefit. This article summarises the latest scientific evidence and clinical trials that support potential therapeutic targets for IgAV-N that are currently being developed based on the evolving understanding of the pathophysiology of IgAV-N. These span the mucosal immunity, B-cell and T-cell modulation, RAAS inhibition, and regulation of complement pathways, amongst others. Novel drugs that may be considered for use in early nephritis include TRF-budesonide; B-cell inhibiting agents including belimumab, telitacicept, blisibimod, VIS649, and BION-1301; B-cell depleting agents such as rituximab, ofatumumab, and bortezomib; sparsentan; angiotensin converting enzyme inhibitors (ACE-Is); and complement pathway inhibitors including avacopan, iptacopan, and narsoplimab. Further clinical trials, as well as pre-clinical scientific studies, are needed to identify mechanistic pathways as there may be an opportunity to prevent nephritis in this condition. Key Points • Kidney involvement is the main cause of long-term morbidity and mortality in IgA vasculitis despite the current treatment recommendations. • The evolving understanding of the pathophysiology of IgA vasculitis is allowing exploration of novel treatment options which target underlying immune pathways. • Novel treatments currently being trialled in IgA nephropathy may have benefit in IgA vasculitis due to the similarities in the underlying pathophysiology, such as TRF-budesonide, B-cell modulators, and complement inhibitors. • Further studies, including clinical trials of novel drugs, are urgently needed to improve the long-term outcomes for children with IgA vasculitis nephritis.

Defining the Surface Oxygen Threshold That Switches the Interaction Mode of Graphene Oxide with Bacteria.

As antimicrobials, graphene materials (GMs) may have advantages over traditional antibiotics due to their physical mechanisms of action which ensure less chance of development of microbial resistance. However, the fundamental question as to whether the antibacterial mechanism of GMs originates from parallel interaction or perpendicular interaction, or from a combination of these, remains poorly understood. Here, we show both experimentally and theoretically that GMs with high surface oxygen content (SOC) predominantly attach in parallel to the bacterial cell surface when in the suspension phase. The interaction mode shifts to perpendicular interaction when the SOC reaches a threshold of ∼0.3 (the atomic percent of O in the total atoms). Such distinct interaction modes are highly related to the rigidity of GMs. Graphene oxide (GO) with high SOC is very flexible and thus can wrap bacteria while reduced GO (rGO) with lower SOC has higher rigidity and tends to contact bacteria with their edges. Neither mode necessarily kills bacteria. Rather, bactericidal activity depends on the interaction of GMs with surrounding biomolecules. These findings suggest that variation of SOC of GMs is a key factor driving the interaction mode with bacteria, thus helping to understand the different possible physical mechanisms leading to their antibacterial activity.

Urinary Protein Array Analysis to Identify Key Inflammatory Markers in Children with IgA Vasculitis Nephritis.

Chronic kidney disease is a recognised complication of immunoglobulin A vasculitis, (IgAV; formerly Henoch-Schonlein purpura-HSP). The pathophysiology of IgAV and why some patients develop significant renal involvement remains largely unknown. Identifying urinary inflammatory markers could direct targets for earlier intervention. The aim of this cross-sectional exploratory study was to perform a large protein array analysis to identify urinary markers to provide insight into the mechanisms of kidney inflammation in children with established IgAV nephritis (IgAVN). Determination of the relative levels of 124 key proteins was performed using commercially available proteome profiler array kits. Twelve children were recruited: IgAVN, n = 4; IgAV without nephritis (IgAVwoN), n = 4; healthy controls (HCs), n = 4. The urinary concentrations of twenty proteins were significantly different in IgAVN compared to IgAVwoN. The largest fold changes were reported for B-cell activating factor (BAFF), Cripto-1, sex-hormone-binding globulin and angiotensinogen. The urinary levels of complement components C5/C5a and factor D were also significantly elevated in patients with IgAVN. A total of 69 urinary proteins significantly raised levels in comparisons made between IgAVN vs. HCs and nine proteins in IgAVwoN vs. HCs, respectively. This study identified key urinary proteins potentially involved in IgAVN providing new insight into the pathophysiology. Further longitudinal studies with larger cohorts are needed to quantitatively analyse these biomarkers.

Understanding the Significance of Sample Preparation in Studies of the Nanoparticle Metabolite Corona.

The adsorption of metabolites to the surface of nanomaterials is a growing area of interest in the field of bionanointeractions. Like its more-established protein counterpart, it is thought that the metabolite corona has a key role in the uptake, distribution, and toxicity of nanomaterials in organisms. Previous research has demonstrated that nanomaterials obtain a unique metabolite fingerprint when exposed to biological matrices; however, there have been some concerns raised over the reproducibility of bionanointeraction research due to challenges in dispersion of nanomaterials and their stability. As such, this work investigates a much-overlooked aspect of this field, i.e., sample preparation, which is vital to the accurate, reproducible, and informative analysis of the metabolite corona. The impact of elution buffer pH, volume, and ionic strength on the metabolite corona composition acquired by uncapped and polyvinylpyrrolidone (PVP)-capped TiO2 from mixtures of cationic and anionic metabolites was studied. We demonstrate the temporal evolution of the TiO2 metabolite corona and the recovery of the metabolite corona, which resulted from a complex biological matrix, in this case human plasma. This work also demonstrates that it is vital to optimize sample preparation for each nanomaterial being investigated, as the metabolite recovery from Fe3O4 and Dispex-capped TiO2 nanomaterials is significantly reduced compared to the aforementioned uncapped and PVP-capped TiO2 nanomaterials. These are important findings for future bionanointeraction studies, which is a rapidly emerging area of research in nanoscience.

Environmental dimensions of the protein corona.

The adsorption of biomolecules to the surface of engineered nanomaterials, known as corona formation, defines their biological identity by altering their surface properties and transforming the physical, chemical and biological characteristics of the particles. In the first decade since the term protein corona was coined, studies have focused primarily on biomedical applications and human toxicity. The relevance of the environmental dimensions of the protein corona is still emerging. Often referred to as the eco-corona, a biomolecular coating forms upon nanomaterials as they enter the environment and may include proteins, as well as a diverse array of other biomolecules such as metabolites from cellular activity and/or natural organic matter. Proteins remain central in studies of eco-coronas because of the ease of monitoring and structurally characterizing proteins, as well as their crucial role in receptor engagement and signalling. The proteins within the eco-corona are optimal targets to establish the biophysicochemical principles of corona formation and transformation, as well as downstream impacts on nanomaterial uptake, distribution and impacts on the environment. Moreover, proteins appear to impart a biological identity, leading to cellular or organismal recognition of nanomaterials, a unique characteristic compared with natural organic matter. We contrast insights into protein corona formation from clinical samples with those in environmentally relevant systems. Principles specific to the environment are also explored to gain insights into the dynamics of interaction with or replacement by other biomolecules, including changes during trophic transfer and ecotoxicity. With many challenges remaining, we also highlight key opportunities for method development and impactful systems on which to focus the next phase of eco-corona studies. By interrogating these environmental dimensions of the protein corona, we offer a perspective on how mechanistic insights into protein coronas in the environment can lead to more sustainable, environmentally safe nanomaterials, as well as enhancing the efficacy of nanomaterials used in remediation and in the agri-food sector.