Molecular dynamics simulations suggest the potential toxicity of fluorinated graphene to HP35 protein via unfolding the α-helix structure

Fluorinated graphene, a two-dimensional nanomaterial composed of three atomic layers, a central carbon layer sandwiched between two layers of fluorine atoms, has attracted considerable attention across various fields, particularly for its potential use in biomedical applications. Nonetheless, scant effort has been devoted to assessing the potential toxicological implications of this nanomaterial. In this study, we scrutinize the potential impact of fluorinated graphene on a protein model, HP35 by utilizing extensive molecular dynamics (MD) simulation methods. Our MD results elucidate that upon adsorption to the nanomaterial, HP35 undergoes a denaturation process initiated by the unraveling of the second helix of the protein and the loss of the proteins hydrophobic core. In detail, substantial alterations in various structural features of HP35 ensue, including alterations in hydrogen bonding, Q value, and RMSD. Subsequent analyses underscore that hydrophobic and van der Waals interactions (predominant), alongside electrostatic energy (subordinate), exert influence over the adsorption of HP35 on the fluorinated graphene surface. Mechanistic scrutiny attests that the unrestrained lateral mobility of HP35 on the fluorinated graphene nanomaterial primarily causes the exposure of HP35's hydrophobic core, resulting in the eventual structural denaturation of HP35. A trend in the features of 2D nanostructures is proposed that may facilitate the denaturation process. Our findings not only substantiate the potential toxicity of fluorinated graphene but also unveil the underlying molecular mechanism, which thereby holds significance for the prospective utilization of such nanomaterials in the field of biomedicine.

Potential toxicity of graphene (oxide) quantum dots via directly covering the active site of anterior gradient homolog 2 protein

Graphene quantum dots (GQDs) have attracted significant attention in biomedicine, while extensive investigations have revealed a reverse regarding the potential biotoxicity of GQDs. In order to supplementing the understanding of the toxicity profile of GQDs, this study employs a molecular dynamics (MD) simulation approach to systematically investigate the potential toxicity of both GQDs and Graphene Oxide Quantum Dots (GOQDs) on the Anterior Gradient Homolog 2 (AGR2) protein, a key protein capable of protecting the intestine. We construct two typical simulation systems, in which an AGR2 protein is encircled by either GQDs or GOQDs. The MD results demonstrate that both GQDs and GOQDs can directly make contact with and even cover the active site (specifically, the Cys81 amino acid) of the AGR2 protein. This suggests that GQDs and GOQDs have the capability to inhibit or interfere with the normal biological interaction of the AGR2 active site with its target protein. Thus, GQDs and GOQDs exhibit potential detrimental effects on the AGR2 protein. Detailed analyses reveal that GQDs adhere to the Cys81 residue due to van der Waals (vdW) interaction forces, whereas GOQDs attach to the Cys81 residue through a combination of vdW (primary) and Coulomb (secondary) interactions. Furthermore, GQDs aggregation typically adsorb onto the AGR2 active site, while GOQDs adsorb to the active site of AGR2 one by one. Consequently, these findings shed new light on the potential adverse impact of GQDs and GOQDs on the AGR2 protein via directly covering the active site of AGR2, providing valuable molecular insights for the toxicity profile of GQD nanomaterials.

Efficient heavy metal ion removal by fluorographene nanochannel templated molecular sieve: a molecular dynamics simulation study

Environmental water contamination, particularly by heavy metal ions, has emerged as a worldwide concern due to their non-biodegradable nature and propensity to accumulate in soil and living organisms, posing a significant risk to human health. Therefore, the effective removal of heavy metal ions from wastewater is of utmost importance for both public health and environmental sustainability. In this study, we propose and design a membrane consisting of fluorographene (F-GRA) nanochannels to investigate its heavy metal ion removal capacity through molecular dynamics simulation. Although many previous studies have revealed the good performance of lamellar graphene membranes for desalination, how the zero-charged graphene functionalized by fluorine atoms (fully covered by negative charges) affects the heavy metal ion removal capacity is still unknown. Our F-GRA membrane exhibits an exceptional water permeability accompanied by an ideal heavy metal ion rejection rate. The superior performance of F-GRA membrane in removing heavy metal ions can be attributed to the negative charge of the F-GRA surface, which results in electrostatic attraction to positively charged ions that facilitates the optimal ion capture. Our analysis of the potential of mean force further reveals that water molecule exhibits the lowest free energy barrier relative to ions when passing through the F-GRA channel, indicating that water transport is energetically more favorable than ion. Additional simulations of lamellar graphene membranes show that graphene membranes have higher water permeabilities compared with F-GRA membranes, while robustly compromising the heavy meal ion rejection rates, and thus F-GRA membranes show better performances. Overall, our theoretical research offers a potential design approach of F-GRA membrane for heavy metal ions removal in future industrial wastewater treatment.

Accuracy of quantitative viral secondary standards: a re-examination

Interlaboratory agreement of viral load assays depends on the accuracy and uniformity of quantitative calibrators. Previous work demonstrated poor agreement of secondary cytomegalovirus (CMV) standards with nominal values. This study re-evaluated this issue among commercially produced secondary standards for both BK virus (BKV) and CMV, using digital polymerase chain reaction (dPCR) to compare the materials from three different manufacturers. Overall, standards showed an improved agreement compared to prior work, against nominal values in both log10 copies/mL and log10 international unit (IU)/mL, with bias from manufacturer-assigned nominal values of 0.0-0.9 log10 units (either copies or IU)/mL. Standards normalized to IU and those values assigned by dPCR rather than by real-time PCR (qPCR) showed better agreement with nominal values. The latter reinforces prior conclusions regarding the utility of using such methods for quantitative value assignment in reference materials. Quantitative standards have improved over the last several years, and the remaining bias from nominal values might be further reduced by universal implementation of dPCR methods for value assignment, normalized to IU.

IMPORTANCE

Interlaboratory agreement of viral load assays depends on accuracy and uniformity of quantitative calibrators. Previous work, published in JCM several years ago, demonstrated poor agreement of secondary cytomegalovirus (CMV) standards with nominal values. This study re-evaluated this issue among commercially produced secondary standards for both BK virus (BKV) and CMV, using digital polymerase chain reaction (dPCR) to compare the materials from three different manufacturers. Overall, standards showed an improved agreement compared to prior work, against nominal values, indicating a substantial improvement in the production of accurate secondary viral standards, while supporting the need for further work in this area and for the broad adaption of international unit (IU) as a reporting standard for quantitative viral load results.

Magnesium Ion Gated Ion Rejection through Carboxylated Graphene Oxide Nanopore: A Theoretical Study

While nanoporous graphene oxide (GO) is recognized as one of the most promising reverse osmosis desalination membranes, limited attention has been paid to controlling desalination performance through the large GO pores, primarily due to significant ion leakage resulting in the suboptimal performance of these pores. In this study, we employed a molecular dynamics simulation approach to demonstrate that Mg2+ ions, adhered to carboxylated GO nanopores, can function as gates, regulating the transport of ions (Na+ and Cl-) through the porous GO membrane. Specifically, the presence of divalent cations near a nanopore reduces the concentration of salt ions in the vicinity of the pore and prolongs their permeation time across the pore. This subsequently leads to a notable enhancement in salt rejection rates. Additionally, the ion rejection rate increases with more adsorbed Mg2+ ions. However, the presence of the adsorbed Mg2+ ions compromises water transport. Here, we also elucidate the impact of graphene oxidation degree on desalination. Furthermore, we design an optimal combination of adsorbed Mg2+ ion quantity and oxidation degree to achieve high water flux and salt rejection rates. This work provides valuable insights for developing new nanoporous graphene oxide membranes for controlled water desalination.

Exceptional metal-semiconductor-metal transition of lead apatites via oxygen defect tuning

Lead apatites, distinguished and compelling bulk materials with the stoichiometric arrangement as Pb10(POx)6Oy, are renowned for their structural complexity. Recently, the discovery of possible room-temperature superconductivity under ambient pressure in copper-substituted lead apatites has engendered considerable interest within both the physics community and beyond. Nevertheless, exploration of pristine Pb10(POx)6Oy parent structures has hitherto remained elusive. In this study, we employ density functional theory (DFT) calculations to investigate the effects of oxygen defects on the electronic structures of Pb10(POx)6Oy and Pb9Cu(POx)6Oy. We scrutinize two distinct categories of defects: oxygen atoms enmeshed within POx groups (Ox) and solitary oxygen atoms (Oy). Our investigation uncovers a profound influence of these defects on the band structure. Specifically, the introduction of Oy defects prompts a remarkable transition in Pb10(PO4)6Oy from a metal to semiconductor to metal state, accompanied by pivotal shifts in the principal electronic contributors from p orbitals of Oy to those of Pb atoms. Furthermore, the introduction of Ox defects in Pb10(POx)6O1 engenders metamorphosis in the band structure, transmuting it from a semiconductor to a metallic state. Significantly, our findings pinpoint the suitable range of x in the Pb10(POx)6O1 configuration as lying between 2 and 4. Additionally, our study also demonstrates that the oxygen defects (Ox/Oy) do not affect the metallic properties of copper-substituted lead apatites. This study elucidates the significant role of oxygen defects in modulating the electronic properties of apatite materials, offering insights into potential interdisciplinary applications. This establishes a crucial link between material composition and electronic behavior, revealing key mechanisms for engineering functionality in lead apatites and other advanced materials.

Villin headpiece unfolding upon binding to boridene mediated by the "anchoring-perturbation" mechanism

We employ molecular dynamics (MD) simulations to investigate the influence of boridene on the behavior of a protein model, HP35, with the aim of assessing the potential biotoxicity of boridene. Our MD results reveal that HP35 can undergo unfolding via an "anchoring-perturbation" mechanism upon adsorption onto the boridene surface. Specifically, the third helix of HP35 becomes tightly anchored to the boridene surface through strong electrostatic interactions between the abundant molybdenum atoms on the boridene surface and the oxygen atoms on the HP35 backbone. Meanwhile, the first helix, experiencing continuous perturbation from the surrounding water solution over an extended period, suffers from potential breakage of hydrogen bonds, ultimately resulting in its unfolding. Our findings not only propose, for the first time to our knowledge, the "anchoring-perturbation" mechanism as a guiding principle for protein unfolding but also reveal the potential toxicity of boridene on protein structures.

Graphene quantum dots blocking the channel egresses of cytochrome P450 enzyme (CYP3A4) reveals potential toxicity

Graphene quantum dots (GQDs) have garnered significant attention, particularly in the biomedical domain. However, extensive research reveals a dichotomy concerning the potential toxicity of GQDs, presenting contrasting outcomes. Therefore, a comprehensive understanding of GQD biosafety necessitates a detailed supplementation of their toxicity profile. In this study, employing a molecular dynamics (MD) simulation approach, we systematically investigate the potential toxicity of GQDs on the CYP3A4 enzyme. We construct two distinct simulation systems, wherein a CYP3A4 protein is enveloped by either GQDs or GOQDs (graphene oxide quantum dots). Our results elucidate that GQDs come into direct contact with the bottleneck residues of Channels 2a and 2b of CYP3A4. Furthermore, GQDs entirely cover the exits of Channels 2a and 2b, implying a significant hindrance posed by GQDs to these channels and consequently leading to toxicity towards CYP3A4. In-depth analysis reveals that the adsorption of GQDs to the exits of Channels 2a and 2b is driven by a synergistic interplay of hydrophobic and van der Waals (vdW) interactions. In contrast, GOQDs only partially obstruct Channel 1 of CYP3A4, indicating a weaker influence on CYP3A4 compared to GQDs. Our findings underscore the potential deleterious impact of GQDs on the CYP3A4 enzyme, providing crucial molecular insights into GQD toxicology.

Moderate binding of villin headpiece protein to C3N3 nanosheet reveals the suitable biocompatibility of this nanomaterial

Since its recent successful synthesis and due to its promising physical and chemical properties, the carbon nitrite nanomaterial, C3N3, has attracted considerable attention in various scientific areas. However, thus far, little effort has been devoted to investigating the structural influence of the direct interaction of this 2D nanomaterial and biomolecules, including proteins and biomembranes so as to understand the physical origin of its bio-effect, particularly from the molecular landscape. Such information is fundamental to correlate to the potential nanotoxicology of the C3N3 nanomaterial. In this work, we explored the potential structural influence of a C3N3 nanosheet on the prototypical globular protein, villin headpiece (HP35) using all-atom molecular dynamics (MD) simulations. We found that HP35 could maintain its native conformations upon adsorption onto the C3N3 nanosheet regardless of the diversity in the binding sites, implying the potential advantage of C3N3 in protecting the biomolecular structure. The adsorption was mediated primarily by vdW interactions. Moreover, once adsorbed on the C3N3 surface, HP35 remains relatively fixed on the nanostructure without a distinct lateral translation, which may aid in keeping the structural integrity of the protein. In addition, the porous topological structure of C3N3 and the special water layer present on the C3N3 holes conjointly contributed to the restricted motion of HP35 via the formation of a high free energy barrier and a steric hindrance to prevent the surface displacement. This work revealed for the first time the potential influence of the 2D C3N3 nanomaterial in the protein structure and provided the corresponding in-depth molecular-level mechanism, which is valuable for future applications of C3N3 in bionanomedicine.

Ultralow lattice thermal conductivities and excellent thermoelectric properties of hypervalent triiodides XI3 (X = Rb, Cs) discovered by machine learning method

Thermal conductivity and power factor are key factors in evaluating heat transfer performance and designing thermoelectric conversion devices. To search for materials with ultralow thermal conductivity and a high power factor, we proposed a set of universal statistical interaction descriptors (SIDs) and developed accurate machine learning models for the prediction of thermoelectric properties. For lattice thermal conductivity prediction, the SID-based model achieved the state-of-the-art results with an average absolute error of 1.76 W m-1 K-1. The well-performing models predicted that hypervalent triiodides XI3 (X = Rb, Cs) have ultralow thermal conductivities and high power factors. Combining first-principles calculations, the self-consistent phonon theory, and the Boltzmann transport equation, we obtained the anharmonic lattice thermal conductivities of 0.10 and 0.13 W m-1 K-1 for CsI3 and RbI3 in the c-axis direction at 300 K, respectively. Further studies show that the ultralow thermal conductivity of XI3 arises from the competition of vibrations between alkali metal atoms and halogen atoms. In addition, at 700 K, the thermoelectric figure of merit ZT values of CsI3 and RbI3 are 4.10 and 1.52, respectively, at the optimal hole doping level, which indicates hypervalent triiodides are potential high performance thermoelectric materials.

MoS2-Plasmonic Nanocavities for Raman Spectra of Single Extracellular Vesicles Reveal Molecular Progression in Glioblastoma

Extracellular vesicles (EVs) are continually released from cancer cells into biofluids, carrying actionable molecular fingerprints of the underlying disease with considerable diagnostic and therapeutic potential. The scarcity, heterogeneity and intrinsic complexity of tumor EVs present a major technological challenge in real-time monitoring of complex cancers such as glioblastoma (GBM). Surface-enhanced Raman spectroscopy (SERS) outputs a label-free spectroscopic fingerprint for EV molecular profiling. However, it has not been exploited to detect known biomarkers at the single EV level. We developed a multiplex fluidic device with embedded arrayed nanocavity microchips (MoSERS microchip) that achieves 97% confinement of single EVs in a minute amount of fluid (<10 μL) and enables molecular profiling of single EVs with SERS. The nanocavity arrays combine two featuring characteristics: (1) An embedded MoS₂ monolayer that enables label-free isolation and nanoconfinement of single EVs due to physical interaction (Coulomb and van der Waals) between the MoS₂ edge sites and the lipid bilayer; and (2) A layered plasmonic cavity that enables sufficient electromagnetic field enhancement inside the cavities to obtain a single EV level signal resolution for stratifying the molecular alterations. We used the GBM paradigm to demonstrate the diagnostic potential of the SERS single EV molecular profiling approach. The MoSERS multiplexing fluidic achieves parallel signal acquisition of glioma molecular variants (EGFRvIII oncogenic mutation and MGMT expression) in GBM cells. The detection limit of 1.23% was found for stratifying these key molecular variants in the wild-type population. When interfaced with a convolutional neural network (CNN), MoSERS improved diagnostic accuracy (87%) with which GBM mutations were detected in 12 patient blood samples, on par with clinical pathology tests. Thus, MoSERS demonstrates the potential for molecular stratification of cancer patients using circulating EVs.

Highly Efficient CO2/C2H2 Separation by Porous Graphene via Quadrupole Gating Mechanism

Acetylene (C₂H₂) is an important and widely used raw material in various industries (such as petrochemical). Generally, a product yield is proportional to the purity of C₂H₂; however, C₂H₂ from a typical industrial gas-production process is commonly contaminated by CO₂. So far, the achievement of high-purity C₂H₂ separated from a CO₂/C₂H₂ mixture is still challenging due to their very close molecular dimensions and boiling temperatures. Taking advantage of their quadrupoles with opposite signs, here, we show that the graphene membrane embedded with crown ether nanopores can achieve an unprecedented separation efficiency of CO₂/C₂H₂. Combining the molecular dynamics simulation and the density functional theory (DFT) approaches, we discovered that the electrostatic gas-pore interaction favorably allows the fast transport of CO₂ through crown ether nanopores while completely prohibiting C₂H₂ transport, which yields a remarkable permeation selectivity. In particular, the utilized crown ether pore is capable of allowing the individual transport of CO₂ while completely rejecting the passage of C₂H₂, independent of the applied pressures, fed gases ratios, and exerted temperatures, featuring the superiority and robustness of the crown pore in CO₂/C₂H₂ separation. Further, DFT and PMF calculations demonstrate that the transport of CO₂ through the crown pore is energetically more favorable than the transport of C₂H₂. Our findings reveal the potential application of graphene crown pore for CO₂ separation with outstanding performance.

Robust Mechanical Destruction to the Cell Membrane of Carbon Nitride Polyaniline (C3N): A Molecular Dynamics Simulation Study

The drug-resistant bacteria, particularly multidrug-resistant bacteria, has emerged as a major global public health concern posing serious threats to human life and survival. Nanomaterials, including graphene, have shown promise as effective antibacterial agents owing to their unique antibacterial mechanism compared with traditional drugs. Despite the structural similarity to graphene, the potential antibacterial activity of carbon nitride polyaniline (C₃N) remains unexplored. In this study, we employed molecular dynamics simulations to investigate the effects of the interaction between the C₃N nanomaterial and the bacterial membrane to evaluate the potential antibacterial activity of C₃N. Our results suggest that C₃N is capable of inserting deep into the bacterial membrane interior, regardless of the presence or absence of positional restraints in the C₃N. The insertion process also resulted in local lipid extraction by the C₃N sheet. Additional structural analyses revealed that C₃N induced significant changes in membrane parameters, including mean square displacement, deuterium order parameters, membrane thickness, and area per lipid. Docking simulations, where all the C₃N are restraint to a specific positions, confirmed that C₃N can extract lipids from the membrane, indicating the strong interaction between the C₃N material and the membrane. Free-energy calculations further revealed that the insertion of the C₃N sheet is energetically favorable and that C₃N exhibits membrane insertion capacity comparable to that observed for graphene, suggesting their potential for similar antibacterial activity. This study provides the first evidence of the potential antibacterial properties of C₃N nanomaterials via bacterial membrane damage and underscores the potential for its use as antibacterial agents in the future applications.

Favorable outcome in advanced pheochromocytoma and paraganglioma after hypofractionated intensity modulated radiotherapy

PURPOSE

The purpose of this study was to review outcomes of patients with advanced/metastatic pheochromocytoma/paraganglioma (PPGL) treated at our institution with Intensity-modulated radiotherapy (IMRT), describe the treatment outcomes, and determine predictors.

METHODS

A retrospective study on patients with advanced/metastatic PPGL who received IMRT at Peking Union Medical College Hospital between 2014 and 2019. A total of 14 patients with 17 lesions were included in this study. Ultra-hypofractionated radiation therapy was used for 7 lesions in 5 patients, while hypofractionated radiation therapy was used for 8 lesions in 7 patients. 2 patients got conventional fractionated radiotherapy. Patients who received external beam radiation therapy were given a median total radiation dose of 74.4/130 Gy (BED10/3) in a median of 13 fractions.

RESULTS

OS at 2 years was 78% for all patients. For lesions evaluated by RECIST response, at least stable disease of the target lesion was achieved in 94% and distant progression in 28.5%, with an average time to progression of 5.2 months. Patients with locally advanced primary tumors or recurred in situ (n = 8) achieved 100% local control, and none of them got recurrence or distant metastasis after radiotherapy at last follow-up (median 29 months). Of patients with catecholamine-related syndromes (n = 12), 91% of symptomatic lesions improved following radiation therapy and a more than 50% decline in catecholamines.

CONCLUSIONS

We have found hypofractionated IMRT effective as an additional therapy for patients with advanced primary tumors or recurrence in situ and not amenable to complete surgical resection.

The single-atom catalytic activity of the hydrogen evolution reaction of the experimentally synthesized boridene 2D material: a density functional theory study

CONTEXT

Previous theoretical studies have suggested that two-dimensional (2D) MBene materials might display adequate monatomic catalytic activity for the hydrogen evolution reaction (HER). Recently, a study reported the experimental synthesis of a 2D MBene (Mo_4/3B₂), re-defined as boridene, albeit no effort has been devoted to explore the single-atom catalytic activity for HER of this experimentally synthesized 2D material. Therefore, we herein investigate the single-atom HER performance of the boridene. Interestingly, with Mo defects mixed with single Au and Zn atoms shows excellent hydrogen evolution performance, and the change in the Gibbs free energy ([Formula: see text]) value is close to 0 eV, which can even match the performance of Pt-based materials. Through analysis of the charge density difference and density of states, the mechanism affecting the HER performance is explained at the electronic level. This work provides a new direction for the use of the Mo_4/3B₂ monolayer two-dimensional materials in the field of single-atom catalysis for HER.

METHODS

This study used the DFT calculations in Vienna ab initio simulation package. The GGA-Perdew-Burke-Ernzerhof functional with DFT-D2 correction is used to describe the exchange-correlation interactions. The projection augmented wave is used with the plane wave cutoff of 500 eV. The convergences of energy and force are 10^-5 eV and 0.01 eV/Å, respectively. A vacuum layer with a height of 20 Å is set in the Z direction. For geometry optimization, self-consistent, and DOS calculations, the k-point grids sampled in Brillouin zones are 3 × 3 × 1, 9 × 9 × 1, and 9 × 9 × 1, respectively. The AIMD simulation is performed in the canonical ensemble (NVT), and the temperature was maintained at 300 K by Nosé-Hoover thermostats with a time step of 2.0 fs.

Insights into the thermodynamic-kinetic synergistic separation of propyne/propylene in anion pillared cage MOFs with entropy-enthalpy balanced adsorption sites

Propyne/propylene (C₃H₄/C₃H₆) separation is an important industrial process yet challenged by the trade-off of selectivity and capacity due to the molecular similarity. Herein, record C₃H₄/C₃H₆ separation performance is achieved by fine tuning the pore structure in anion pillared MOFs. SIFSIX-Cu-TPA (ZNU-2-Si) displays a benchmark C₃H₄ capacity (106/188 cm³ g^-1 at 0.01/1 bar and 298 K), excellent C₃H₄/C₃H₆ IAST selectivity (14.6-19.3) and kinetic selectivity, and record high C₃H₄/C₃H₆ (10/90) separation potential (36.2 mol kg^-1). The practical C₃H₄/C₃H₆ separation performance is fully demonstrated by breakthroughs under various conditions. 37.8 and 52.9 mol kg^-1 of polymer grade C₃H₆ can be produced from 10/90 and 1/99 C₃H₄/C₃H₆ mixtures. 4.7 mol kg^-1 of >99% purity C₃H₄ can be recovered by a stepped desorption process. Based on the in situ single crystal analysis and DFT calculation, an unprecedented entropy-enthalpy balanced adsorption pathway is discovered. MD simulation further confirmed the thermodynamic-kinetic synergistic separation of C₃H₄/C₃H₆ in ZNU-2-Si.

Efficient Seawater Desalination in Lamellar Nanochannels Based Boridene Filtration Membrane

With the progressively increasing demand of freshwater, the shortage of global freshwater resources has become one of the most serious events that all humans are facing now. The reverse osmosis...

Matrix Matters: Assessment of Commutability among BK Virus Assays and Standards

Quantitative testing of BK virus (BKPyV) nucleic acid has become the standard of care in transplant patients. While the relationship between interassay harmonization and commutability has been well characterized for other transplant-related viruses, it has been less well studied for BKPyV, particularly regarding differences in commutability between matrices. Here, interassay agreement was evaluated among six real-time nucleic acid amplification tests (NAATs) and one digital PCR (dPCR) BKPyV assay. Differences in the commutability of three quantitative standards was examined across all assays using a variety of statistical approaches. Panels, including 40 samples each of plasma and urine samples previously positive for BKPyV, together with one previously negative plasma sample and four previously negative urine samples, were tested using all assays, with each real-time NAAT utilizing its usual quantitative calibrators. Serial dilutions of WHO, National Institute for Standards and Technology (NIST), and commercially produced (Exact/Bio-Rad) reference materials were also run by each assay as unknowns. The agreement of the clinical sample values was assessed as a group and in a pairwise manner. The commutability was estimated using both relativistic and quantitative means. The quantitative agreement across assays in the urine samples was within a single log10 unit across all assays, while the results from the plasma samples varied by 2 to 3 log10 IU/mL. The commutability showed a similar disparity between the matrices. Recalibration using international standards diminished the resulting discrepancies in some but not all cases. Differences in the sample matrix can affect the commutability and interassay agreement of quantitative BKPyV assays. Differences in commutability between matrices may largely be due to factors other than those such as amplicon size, previously described as important in the case of cytomegalovirus. Continued efforts to standardize viral load measurements must address multiple sources of variability and account for differences in assay systems, quantitative standards, and sample matrices.

Ionic Liquid Decelerates Single-Stranded DNA Transport through Molybdenum Disulfide Nanopores

Nanopores in two-dimensional (2D) materials have emerged to offer in principle necessary spatial resolution for high-throughput DNA sequencing. However, their fidelity is severely limited by the fast DNA translocation. A recent experiment indicates that introducing ionic liquids could slow down DNA translocation in a MoS₂ nanopore. However, the corresponding in-depth molecular mechanism underlying the experimental findings is not fully understood, which is crucial for the future improvement of rational DNA translocation control. Here, we computationally investigate and then experimentally identify the effect of BmimCl ionic liquid on the retardation of ssDNA translocation through a single-layer MoS₂ nanopore. Our all-atom molecular dynamics simulations demonstrate that the strong interaction between Bmim⁺ and ssDNA offers a considerable dragging force to decelerate the electrophoretic motion of ssDNA in the BmimCl solution. Moreover, we show that Bmim⁺ ions exhibit preferential binding on the sulfur edges of the nanopore. These Bmim⁺ in the pore region can not only act as a steric blockage but also form π-π stackings with nucleobases, which provide a further restriction on the ssDNA motion. Therefore, our molecular dynamics simulation investigations deepen the understanding of the critical role of ionic liquid in DNA translocation through a nanopore from a molecular landscape, which may benefit practical implementations of ionic liquids in nanopore sequencing.

Crown Nanopores in Graphene for CO2 Capture and Filtration

With growing concerns about global warming, it has become urgent and critical to capture carbon from various emission sources (such as power plants) and even directly from air. Recent advances in materials research permit the design of various efficient approaches for capturing CO₂ with high selectivity over other gases. Here, we show that crown nanopores (resembling crown ethers) embedded in graphene can efficaciously allow CO₂ to pass and block other flue gas components (such as N₂ and O₂). We carried out extensive density functional theory-based calculations as well as classical and ab initio molecular dynamics simulations to reveal the energetics and dynamics of gas transport through crown nanopores. Our results highlight that the designed crown nanopores in graphene possess not only an excellent selectivity for CO₂ separation/capture but also fast transport (flow) rates, which are ideal for the treatment of flue gas in power plants.

Unexpected hydrophobicity on self-assembled monolayers terminated with two hydrophilic hydroxyl groups

Current major approaches to access surface hydrophobicity include directly introducing hydrophobic nonpolar groups/molecules onto the surface or elaborately fabricating surface roughness. Here, for the first time, molecular dynamics simulations show an unexpected hydrophobicity with a contact angle of 82° on a flexible self-assembled monolayer terminated only with two hydrophilic OH groups ((OH)₂-SAM). This hydrophobicity, verified by a water slip phenomenon characterizing the friction on the (OH)₂-SAM surface, is attributed to the formation of a hexagonal-ice-like H-bonding structure in the OH matrix of (OH)₂-SAM, which sharply reduces the hydrogen bonds between the surface and the water molecules above. The unique simple interface presented here offers a significant molecular-level platform for examining the bio-interfacial interactions ranging from biomolecule binding to cell adhesion.

Application Prospects and Prospect of Metabolomics in the Identification of Sudden Cardiac Death

Abstract

In cases of sudden death, the prevention of sudden cardiac death and the analysis of the cause of death after sudden cardiac death have always been a difficult problem. Therefore, clinical research and forensic pathological identification of sudden cardiac death are of great significance. In recent years, metabolomics has gradually developed into a popular field of life science research. The detection of "metabolic fingerprints" of biological fluids can provide an important basis for early diagnosis of diseases and the discovery of potential biomarkers. This article reviews the current research status of sudden cardiac death and the research on metabolomics of cardiovascular diseases that is closely related to sudden cardiac death and analyzes the application prospects of metabolomics in the identification of the cause of sudden cardiac death.

Membrane Insertion of MoS2 Nanosheets: Fresh vs. Aged

Fresh two-dimensional molybdenum disulfide (MoS₂) absorbs the hydrocarbon contaminations in the ambient air and makes surface aging. To understand how the surface aging influences the interactions between MoS₂ and biomolecules is important in the biomedical applications. Here, employing all-atom molecular dynamics simulations, we investigated the interactions of the fresh and aged MoS₂ nanosheets with the lipid membranes of different components. Our results demonstrate that both the fresh and aged MoS₂ nanosheets can spontaneously insert into the bilayer membranes. However, the fresh MoS₂ nanosheet displays significantly stronger interaction and then has a larger penetration depth than the aged counterpart, regardless of the lipid components. The calculations of potential mean forces through the umbrella sampling further confirm that the insertion of fresh MoS₂ into the lipid membranes is more energetically favorable. Moreover, we found that the fresh MoS₂ nanosheet can cause a larger damage to the integrity of lipid membranes than the aged one. This work provides insightful understandings of the surface-aging-dependent interactions of the MoS₂ nanosheets with biomembranes, which could facilitate the design of novel MoS₂-based nanodevices with advanced surface properties.

Multifaceted Regulation of Potassium-Ion Channels by Graphene Quantum Dots

Graphene quantum dots (GQDs) are emerging as a versatile nanomaterial with numerous proposed biomedical applications. Despite the explosion in potential applications, the molecular interactions between GQDs and complex biomolecular systems, including potassium-ion (K+) channels, remain largely unknown. Here, we use molecular dynamics (MD) simulations and electrophysiology to study the interactions between GQDs and three representative K+ channels, which participate in a variety of physiological processes and are closely related to many disease states. Using MD simulations, we observed that GQDs adopt distinct contact poses with each of the three structurally distinct K+ channels. Our electrophysiological characterization of the effects of GQDs on channel currents revealed that GQDs interact with the extracellular voltage-sensing domain (VSD) of a Kv1.2 channel, augmenting current by left-shifting the voltage dependence of channel activation. In contrast, GQDs form a "lid" cluster over the extracellular mouth of inward rectifier Kir3.2, blocking the channel pore and decreasing the current in a concentration-dependent manner. Meanwhile, GQDs accumulate on the extracellular "cap domain" of K2P2 channels and have no apparent impact on the K+ flux through the channel. These results reveal a surprising multifaceted regulation of K+ channels by GQDs, which might help de novo design of nanomaterial-based channel probe openers/inhibitors that can be used to further discern channel function.

POS0788 CIRCULATING EXOSOMES PROMOTE LUPUS NEPHRITIS IN MRL-LPR MICE

Background:

Systemic Lupus Erythematosus (SLE) is a prototypic autoimmune disease that characterized by the loss of self-tolerance and the production of autoantibodies (autoAbs) [1, 2]. Lupus nephritis (LN), the severe organ-threatening manifestations of SLE, could cause massive damage to patients[3, 4]. Currently, some exosomal microRNAs (miRNAs) are considered as potential biomarkers in SLE. However, the role of exosomal miRNAs in Lupus Nephritis (LN) remains unclear.

Objectives:

The purpose of this study was to investigate molecular mechanism of plasma exosomal miRNAs in the development of Lupus Nephritis.

Methods:

Circulating exosomes were isolated from plasma of patients with LN, SLE without LN (NLN). Plasma exosomes were authenticated by Western Blot, Nanosight Tracking Analysis (NTA) and transmission electron microscopy (TEM). Fluorescence microscopy of co-cultured plasma exosomes and podocytes demonstrated that exosomes were uptaken into podocytes. Moreover, cell apoptosis and the inflammation factors was assessed using Western Blot. We analyzed the expression profiles of miRNAs in LN and NLN exosomes and the expression profiles of mRNAs of podocytes stimulated with LN and NLN exosomes with the help of next generation sequencing (NGS).

Results:

We demonstrate that exosomes derived from LN plasma could be taken by neighboring podocytes and promote the apoptosis of podocytes and the expression of inflammation factors. In addition, the sequencing found that miRNAs were differentially expressed in LN and NLN exosomes and mRNAs were differentially expressed in podocytes stimulated with LN and NLN exosomes.

Conclusion:

LN plasma exosomes have a potency to stimulate the apoptosis of podocytes and the expression of inflammation factors. Moreover, differentially expressed miRNAs in exosomes play a potential role in the development of LN.

References:

[1]T. Colasanti, A. Maselli, F. Conti, M. Sanchez, C. Alessandri, C. Barbati, D. Vacirca, A. Tinari, F. Chiarotti, A. Giovannetti, F. Franconi, G. Valesini, W. Malorni, M. Pierdominici, E. Ortona, Autoantibodies to estrogen receptor α interfere with T lymphocyte homeostasis and are associated with disease activity in systemic lupus erythematosus, Arthritis and rheumatism, 64 (2012) 778-787.

[2]H.A. Al-Shobaili, A.A. Al Robaee, A.A. Alzolibani, Z. Rasheed, Antibodies against 4-hydroxy-2-nonenal modified epitopes recognized chromatin and its oxidized forms: role of chromatin, oxidized forms of chromatin and 4-hydroxy-2-nonenal modified epitopes in the etiopathogenesis of SLE, Disease markers, 33 (2012) 19-34.

[3]A. Kaul, C. Gordon, M.K. Crow, Z. Touma, M.B. Urowitz, R. van Vollenhoven, G. Ruiz-Irastorza, G. Hughes, Systemic lupus erythematosus, Nat Rev Dis Primers, 2 (2016) 16039.

[4]M.G. Tektonidou, A. Dasgupta, M.M. Ward, Risk of End-Stage Renal Disease in Patients With Lupus Nephritis, 1971-2015: A Systematic Review and Bayesian Meta-Analysis, Arthritis & rheumatology (Hoboken, N.J.), 68 (2016) 1432-1441.

Disclosure of Interests:

None declared

AB0343 THE CHARACTERISTICS OF T CELLS IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS WITH ANXIETY BASED ON MACHINE LEARNING

Background:

Systemic lupus erythematosus (SLE) is an autoimmune disease, the immune system of patients to be disordered, especially in T cell subsets1. They were prone to mental diseases, anxiety particularly, which lead to suicide2. The recent study had reported that CD4+ T cells in the peripheral blood played the key role in like anxiety behavior of mice3. Although there showed that the level of serum TNF-α in SLE patients with anxiety was higher than without anxiety4, finding the important special mediators especially in T cell subsets was still necessary for the prevention of anxiety in SLE patients.

Objectives:

In total, 108 SLE patients, which met the diagnostic criteria of the American Society of rheumatology (v1997), were enrolled in this study from Affilliated Hospital of Nantong University, China. Exclusion criteria included other autoimmune diseases and active infection (including hepatitis B or C virus, Epstein-Barr virus, human immunodeficiency virus or Mycobacterium tuberculosis infection).

Methods:

We surveyed the abundance of 74 immune cell subpopulations from 108 SLE patients using flow cytometry, and investigated their differences between patients with and without anxiety (24 versus 84). Moreover, machine learning including Lasso regression, Random forest (RF) and Sparsity partial least squares discriminant analysis (sPLS-DA) was employed to build models and futher selected important features for the classification of SLE patients with anxiety.

Results:

SLE patients with anxiety showed higher body mass index (BMI) and lower quality of life. In their peripheral blood, the proportion of internal cell subsets composition of Th cell and Treg cells changed. By machine learning, we finally found that BMI and PD1-CD28- Treg played important rules to developing lupus anxiety.

Conclusion:

In this study, machine learning was applied to build models to select the most important T cell subset in SLE patients with anxiety. These findings suggested that BMI and imbalance of PD1-CD28- Treg containing effector memory Treg cells and effector Treg cells mostly played important roles in the development of SLE anxiety.

Disclosure of Interests:

None declared

POS0401 THE APPLICATION OF MTX-LOADING DNA TETRAHEDRON IN TREATING COLLAGEN-INDUCED ARTHRITIS MICE VIA REGULATING MACROPHAGE

Background:

Rheumatoid arthritis (RA) is a systemic autoimmune disease which mainly affect joints. [1]. Macrophages often infiltrate in the inflammatory joints. Activated macrophages release TNF-α, IL-1β to accelerate tissue damage, is one of the most important targets for RA intervention. The traditional drugs currently used commonly have some disadvantages cannot be bypassed[2], while DNA nanostructure is a new type of drugs have precise design, and likewise takes biological effect together[3]. We synthesized a DNA tetrahedron loaded with MTX and conjugated with HA which targeted to macrophage.

Objectives:

To verify whether MTX-loading DNA tetrahedron can regulate the apoptosis and polarization of macrophage and finally improve the condition of CIA model mice by while decrease the side effect of MTX.

Methods:

DNA TET was synthesized by mixing signal strand DNA in TM buffer and heated to 95 °C for 10 min, then cooling to 4 °C. Electrophoresis was applied to confirm the formation of TET. The absorbance of MTX solution was detected by microplate reader to analyze the loading efficiency of MTX into TET. Fluorescence microscope was used to observe the intake of TET into cells. CCK8 experiment was applied to measure the vitality of cells. Flow cytometry was used to detect the apoptosis and polarization. CIA model was established based on DBA/1 mice. Mice were randomly divided into five groups: normal group injected with NS; after established CIA model, CIA group injected with NS, MTX group injected with MTX solution, MTX-TET group injected with MTX-TET NP.

Results:

We synthesized DNA tetrahedron(A) and used 8% PAGE electrophoresis to confirmed the successfully synthesis(B). Then We found that when TET concentration fixed, the loading MTX concentration gradually increased and saturated at 190μM(C). While completely loading needed at least 4 hours(D). Fluorescence showed that single DNA strand cannot be taken by RAW, while TET can be easily taken by RAW(E). CCK8 showed that empty TET had no obvious effect on cells, while MTX and MTX-TET with equivalent concentration can obviously suppress the vitality(F). Similarly, the apoptosis trial showed that TET can slightly decrease the apoptosis of RAW, MTX and MTX-TET can significantly promote the apoptosis(G). Flow cytometry showed that the MTX-TET can decrease the expression of M1 marker CD80 (H).

At last, we treat mice with NS, TET, MTX and MTX-TET once a week after CIA model established, and found that TET have no significantly effect on mice, while MTX and MTX-TET can alleviate the inflammation symptom of paws(I).

Conclusion:

Conclusions: We synthesized MTX-loading DNA tetrahedron conjugated with HA, and found that the MTX-TET NP have the excellent ability of promote RAW apoptosis and relieve proinflammatory M1 polarization. while also can alleviate the symptom of CIA mice.

References:

[1]Aletaha D, Smolen JS: Diagnosis and Management of Rheumatoid Arthritis: A Review. JAMA 2018, 320(13):1360-1372.

[2]Smolen JS, Aletaha D, McInnes IB: Rheumatoid arthritis. Lancet 2016, 388(10055):2023-2038.

[3]Hu Q, Li H, Wang L, Gu H, Fan C: DNA Nanotechnology-Enabled Drug Delivery Systems. Chem Rev 2019, 119(10):6459-6506.

Figure 1.

Disclosure of Interests:

None declared

OP0073 SINGLE-CELL TRANSCRIPTOMICS UNCOVERS DEFECTIVE BONE MARROW EARLY B CELL DEVELOPMENT IN A SUBSET OF LUPUS PATIENTS ASSOCIATED WITH AGGRAVATED INFLAMMATION

Background:

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that occurs when the body’s immune system attacks own tissues and organs. B cells play a central role in SLE pathogenesis by producing autoantibodies as well as antibody-independent functions. Peripheral B cell abnormality is well known in lupus patients such as expansions of plasmablasts and atypical memory B cells, which are associated with active diseases. However, little is known about the B cell development in the bone marrow of lupus patients.

Objectives:

We conduct this survey to explore the disorder of the B cell development in the bone marrow of lupus patients.

Methods:

In this study, we have performed the scRNASeq to profile the bone marrow B cell compartment in lupus patients and healthy donors.

Results:

We identified that in a subset of lupus patients, the early B cells (proB and preB cells) were strongly decreased, which were confirmed by flow cytometry in an expanded cohort. Furthermore, bone marrow B cells from these patients showed a strong proinflammatory signature revealed by pathway analysis. Interestingly, BCR repertoire analysis showed that the IGHV-4-34 was highly enriched in these patients, indicating an enhanced B cell tolerance defect. Finally, a panel of proinflammatory cytokines (TNF-a, IL-1a, IL-12p70, IFN-g, et al.) were strongly increased in the bone marrow plasma of these patients compared with early B normal patients and healthy donors, confirming a localized proinflammatory microenvironment.

Conclusion:

Altogether, the current study has revealed that a defective early B cell development in lupus patients is associated with a more severe B cell tolerance defect and aggravated inflammation, which may shed new light on developing novel therapies by targeting relevant pathways.

References:

[1]Min Wang, Hua Chen, Jia Qiu, et al. Antagonizing miR-7 suppresses B cell hyperresponsiveness and inhibits lupus development. J Autoimmun 2020.

[2]A M Jacobi, D M Goldenberg, F Hiepe, et al. Differential effects of epratuzumab on peripheral blood B cells of patients with systemic lupus erythematosus versus normal controls. Ann Rheum Dis, 2008.

Acknowledgements:

This work was funded by Special project of clinical medicine of Nantong University (Grant/Award number: 2019LQ001), National Natural Science Foundation of China (Grant/Award number: 81671616, 81871278 and 82071838).

Disclosure of Interests:

None declared

AB0639 EXOSOMES DERIVED FROM ENDOTHELIAL CELLS PREVENT OSTEOBLAST APOPTOSIS IN STEROID-INDUCED OSTEONECROSIS OF THE FEMORAL HEAD RAT MODEL VIA THE PI3K/AKT/Bcl-2 SIGNAL PATHWAY

Background:

Osteonecrosis of the femoral head (ONFH) is a common disease caused by many trauma factors and un-trauma factors. Among those un-trauma factors, steroid-induced osteonecrosis of the femoral head (SNFH) accounted for a large proportion and mainly concentrated in young people. SNFH has been reported as an irreversible disease and associated with the damage of blood vessels and the loss balance of bone homeostasis. Circulating endothelial progenitor cells (CEPCs), one part of circulating endothelial cells (CECs), are immature precursor cells with proliferative potential. The damage of vascular endothelial cells in SNFH has been confirmed by many studies, but the changes of CECs and CEPCs in the peripheral blood of patients with SNFH have not been studied yet.

Objectives:

The objective of the study is to explore the number of CECs and CEPCs in SNFH patients and normal people and then investigate whether EC-secreted exosomes (EC-exos) could prevent the progression of SNFH in rat model and its mechanism of action.

Methods:

We collect peripheral blood of 3 SNFH patients and 3 heathy people and detected the levels of CECs and CEPCs by Flow cytometer. TEM, NTA and western blot was used to characterize the isolated EC-exos. Annexin V-FITC/PI double staining with flow cytometric analysis and western blot were used to evaluate MC3T3-E1 cells apoptosis. CCK-8, scratching experiment and transwell were used to evaluate MC3T3-E1 cells viability and migration ability. Micro-CT and morphological staining were used to evaluate the progress of SNFH in rat model.

Results:

Firstly, we found that the number of CECs and CEPCs in the peripheral blood was decreased in SNFH patients than normal people. Then our results indicated that EC-exos could improve the migration, viability and prevent apoptosis of osteoblasts under dexamethasone by activating the PI3K/AKT/Bcl-2 signal pathway in vitro. Finally, our Micro-CT and morphological staining results in SNFH rat model revealed that EC-exos prevented the progression of SNFH.

Conclusion:

EC-exos could enhance the cell viability and migration ability of osteoblasts under dexamethasone and play an anti-apoptosis role against steroids-induced osteoblast apoptosis by activating the PI3K/AKT/Bcl-2 signal pathway. EC-exos prevented the progression of SNFH in rat model.

References:

[1]Zalavras CG, Lieberman JR. Osteonecrosis of the femoral head: evaluation and treatment. J Am Acad Orthop Surg. 2014;22(7):455-64.

[2]Microsurgery Department of the Orthopedics Branch of the Chinese Medical Doctor A, Group from the O, Bone Defect Branch of the Chinese Association of R, Reconstructive S, Microsurgery, Reconstructive Surgery Group of the Orthopedics Branch of the Chinese Medical A. Chinese Guideline for the Diagnosis and Treatment of Osteonecrosis of the Femoral Head in Adults. Orthop Surg. 2017;9(1):3-12.

[3]Mont MA, Jones LC, Hungerford DS. Nontraumatic osteonecrosis of the femoral head: ten years later. J Bone Joint Surg Am. 2006;88(5):1117-32.

[4]Yuan HF, Zhang J, Guo CA, Yan ZQ. Clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation: a meta-analysis of seven case-control studies. Clinics (Sao Paulo). 2016;71(2):110-3.

[5]Houdek MT, Wyles CC, Packard BD, Terzic A, Behfar A, Sierra RJ. Decreased Osteogenic Activity of Mesenchymal Stem Cells in Patients With Corticosteroid-Induced Osteonecrosis of the Femoral Head. J Arthroplasty. 2016;31(4):893-8.

Disclosure of Interests:

None declared.

POS0787 BERBERINE MODULATE LUPUS SYNDROME VIA THE REGULATION OF GUT MICROBIOTA IN MRL/LPR MICE

Background:

Intestinal flora disorder and immune abnormalities have been reported in systemic lupus erythematosus (SLE) patients1,2. Berberine (BBR) showed significant effects in regulating the intestinal flora, repairing gut barriers and regulating immune cells3,4. While few reports mentioned the abnormal gut microbiota and metabolites in Chinese SLE patients.

Objectives:

Our investigation tried to illustrate the relationship between gut microbiota, intestinal metabolites and disease activity in Chinese SLE patients. And the effect of BBR to intestinal dysbacteriosis, multiple organ damages and over-activated immune system in MRL/Lpr mice.

Methods:

16S high-throughput (16S rRNA) sequence, qRT-PCR and gas chromatography technology were used to determine the gut microbiota and metabolites in 104 SLE patients from Affiliated Hospital of Nantong University, China. BBR was orally treated to the MRL/Lpr mice in low, medium and high doses. After 6 weeks treatment, mice were sacrificed. Serum, faeces and organs were collected for further studies.

Results:

Chinese SLE patients showed higher abundance of Bacteroidetes and lower abundance of Firmcutes. The results of qRT-PCR showed high Firmcutes/Bacteroidetes (F/B) ratio of SLE patients. The F/B ratio was negative correlated with SLE disease activity index (SLEDA) score. Almost all the tested short-chain fatty acids (SCFAs) found statistically significant results in SLE and LN (lupus nephritis) patients, especially the propanoic acid and butyric. BBR altered the relative abundance of Bacteroides and Verrucomicrobia and the butyric acid content in colon of MRL/Lpr mice. The increase of tight junction protein also indicated the gut barrier was repaired by BBR. Treg and Tfr cells in spleen and mesenteric lymph node (MLN) were increased. These results revealed a positive therapeutic effect of berberine on SLE from gut microbiota to immune status.

Conclusion:

Our study highlights current status of intestinal dysbacteriosis in Chinese patients with SLE and differences in intestinal metabolites among patients with different disease states. The regulation of intestinal flora and the repairment of gut barrier by intestinal metabolites in BBR treated mice seemed to be the factor that directed the immune responses and disease outcomes. The ultimate goal of our study was to determine the beneficial effects of regulating the gut microbiota on the treatment of SLE. The application of berberine is a relatively safe and convenient way. In the coming investigations, we plan to focus on the study of berberine and its metabolites on intestinal function and systemic immunity.

References:

[1]Guo, M. et al. Alteration in gut microbiota is associated with dysregulation of cytokines and glucocorticoid therapy in systemic lupus erythematosus. Gut microbes11, 1758-1773, doi:10.1080/19490976.2020.1768644 (2020).

[2]Mu, Q. et al. Control of lupus nephritis by changes of gut microbiota. Microbiome5, 73, doi:10.1186/s40168-017-0300-8 (2017).

[3]Habtemariam, S. Berberine pharmacology and the gut microbiota: A hidden therapeutic link. Pharmacological research155, 104722, doi:10.1016/j.phrs.2020.104722 (2020).

[4]Cui, H. et al. Berberine Regulates Treg/Th17 Balance to Treat Ulcerative Colitis Through Modulating the Gut Microbiota in the Colon. Frontiers in pharmacology9, 571, doi:10.3389/fphar.2018.00571 (2018).

Figure 1.

Disclosure of Interests:

None declared

POS0761 INVESTIGATION ON THE EFFECT AND MECHANISM OF ABNORMALLY ACTIVATED CD8+ T CELLS FROM BONE MARROW ON HEMATOPOIETIC STEM CELLS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

SLE is an autoimmune disease characterized by the abnormal function of lymphocytes. The impairment of hematopoietic function of bone marrow participates in its pathogenesis, in which T cells play an important role. However, study on bone marrow T cells in SLE patients is very limited.

Objectives:

This study aims to characterize the phenotype and molecular characteristics of abnormally activated CD8+T cells in bone marrow of SLE patients and explore the mechanism of hematopoietic stem cells (HSCs) reduction caused by the abnormally activated CD8+T cells in bone marrow of patients with SLE.

Methods:

A total of 8 SLE patients and 5 age- and sex-matched controls were recruited in our study. Among them, 3 SLE patients and 4 donors were collected bone marrow and peripheral blood samples for Single-cell RNA sequencing (scRNA-seq) and functional studies. BM and peripheral T cell subsets were measured by flow cytometry. Plasma cytokines and secreted immunoglobulins were detected by Luminex. Disease activity of SLE patients was measured using the SLE Disease Activity Index (SLEDAI). All analyses were performed using R language and Flowjo 9.

Results:

In the present study, SLE patients had increased CD8+T%αβT cells and decreased CD4+T%αβT cells in bone marrow of SLE, compared to healthy controls. A large number of CD38+HLADR+CD8+T cells existed in the bone marrow and peripheral blood of SLE patients. Those patients also showed reduced number of HSCs, and with a downward trend of the numbers of peripheral red blood cells, white blood cells, neutrophils, hemoglobin, and platelets. By scRNA-seq, the CD38+HLADR+CD8+T cells contained high levels of GZMK, GZMA, PRF1, IFNG, and TNF in the bone marrow of SLE patients. the CD38+HLADR+CD8+T cells exhibited significant relationship with HSCs, white blood cells, neutrophils, and platelets.

Conclusion:

These findings demonstrated that the abnormally activated CD8+T cells in bone marrow can reduce the number of HSCs by the expression of killer molecules, which contributes to the impairment of hematopoietic function and the development of SLE. This project focuses on the specific bone marrow T cell subset in SLE. The completement of this project provides information for exploring the mechanism of hematopoiesis involvement.

References:

[1]Anderson E, Shah B, Davidson A, Furie R. Lessons learned from bone marrow failure in systemic lupus erythematosus: Case reports and review of the literature. Semin Arthritis Rheum. 2018;48(1):90-104.

[2]Sun LY, Zhou KX, Feng XB, Zhang HY, Ding XQ, Jin O, Lu LW, Lau CS, Hou YY, Fan LM. Abnormal surface markers expression on bone marrow CD34+cells and correlation with disease activity in patients with systemic lupus erythematosus. Clin Rheumatol. 2007;26(12):2073-2079.

Acknowledgements:

We want to thank Lu Meng, Teng Li, Wei Zhou, and Jiaxin Guo for their assistance with this study.

Disclosure of Interests:

None declared

POS0785 CHANGING EXPRESSION PROFILES OF LONG NONCODING RNAS, MIRNAS, MRNAS AND CIRCULAR RNAS IN LABIAL SALIVARY GLANDS OF PRIMARY SJÖGREN’S SYNDROME (PSS)

Background:

Primary Sjögren’s syndrome (pSS) is a relatively common autoimmune disease characterized by oral and ocular dryness. An increasing number of studies have revealed that long non-coding RNA (lncRNA), miRNA, mRNA and circular RNA (circRNA) contributes to the pathogenesis of autoimmune diseases.

Objectives:

To explore lncRNA, miRNA, mRNA and circRNA expression profiles in labial salivary glands (LSGs) in pSS patients and their biological functions in the regulation of pSS.

Methods:

The expression of 75,550 lncRNAs, 2,318 miRNA, 20,292 mRNAs and 6,877 circRNAs were determined in the LSG of six pSS patients and six healthy controls using microarray experiments. Validation was performed in pSS patients and controls using real-time PCR. LncRNA-mRNA co-expression and gene-pathway networks were constructed using bioinformatics software.

Results:

A total of 599 lncRNAs (upregulated: 279, downregulated: 320), 78 miRNAs (upregulated: 26, downregulated: 52), 615 mRNAs (upregulated: 590, downregulated: 25) and 160 mRNAs (upregulated: 110, downregulated: 50) were differentially expressed in the LSGs of pSS patients. Five of these lncRNAs were validated using real-time PCR. lncRNA HCP5, lncRNA SNHG5, lncRNA IFI44L, lncRNA CMPK2 were significantly upregulated and lncRNA TTYH1 were downregulated in pSS. GO and KEGG biological pathway analysis were performed to predict the functions of differentially expressed lncRNAs and co-expressed potential targeting genes. Subsequently, a ceRNA (lncRNA-miRNA-mRNA) network including 2320 ceRNA pairs was constructed based on predicted miRNAs shared by lncRNAs and mRNAs.

Conclusion:

The expression profile provided a systematic perspective on the potential functions of lncRNAs miRNAs, mRNAs and circRNAs in the pathogenesis of pSS. Therefore, this study will aid in the development of new diagnostic biomarkers and drug therapies.

References:

[1]Le Dantec C, Varin MM, Brooks WH, Pers JO, Youinou P, Renaudineau Y. Epigenetics and Sjogren’s syndrome.Curr Pharm Biotechnol. 2012 Aug;13(10):2046-53.

Disclosure of Interests:

None declared

AB0146 HAND AND WRIST ACTIVE RANGE OF MOTIONS AND CONTRIBUTING FACTORS IN RHEUMATOID ARTHRITIS: A CROSS-SECTIONAL STUDY

Background:

Patients with rheumatoid arthritis (RA) usually impaired range of motions (ROMs), especially hand and wrist active ROMs (AROMs), thus influencing their ability to perform daily activities and health-related quality of life (HR-QoL). However, little is known about the potential factors of reduced hand and wrist AROMs and their relations to quality of life in Chinese RA patients.

Objectives:

To explore the contributing factors of hand and wrist AROMs and their associations with HR-QoL and functional limitation in Chinese RA population.

Methods:

In this cross-sectional study, 108 patients were enrolled from Affiliated Hospital of Nantong University between November 2018 and July 2019. We measured all the participants’ AROMs with different directions of the hand and wrist in both sides, including volar flexion, ulnar deviation, radial deviation and radial deviation of the wrist joint, the first metacarpophalangeal (MCP1) flexion, interphalangeal (IP) flexion, volar abduction, radial abduction and thumb opposition (cm) in the thumb, average flexion, hypertension and abduction of the MCP2-5, average proximal interphalangeal (PIP) 2-5 and distal interphalangeal (DIP) 2-5 flexions, total active range of motion (TAM) of the second to the fifth fingers (TAM2-TAM5). Their sociodemographic, physical, psychological, disease-related data, acute phase reactants, laboratory indicators, drug usage and HR-QoL were examined as well. Statistical analysis used Pearson’s and Spearman’s correlation analysis, univariate and multivariate linear regression analyses.

Results:

In univariate analyses, we found that living in rural area, longer disease duration, comorbidity, hospitalization, more swollen joints, higher disease activity, pain level, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), red blood cell count and glucocorticoids usage were associated with most of the decreased hand and wrist AROMs (P ≤ 0.050), while higher education and annual income were related to most of the increased hand and wrist AROMs (P ≤ 0.048). In multivariate analyses, higher disease duration (P ≤ 0.023) and higher disease activity (P ≤ 0.033) were corelated with most of the decreased hand and wrist AROMs. Interestingly, the psychological factor, anxiety, was only positively associated with thumb opposition in both univariate and multivariate analyses (P ≤ 0.001). Additionally, most of the declined hand and wrist AROMs were associated with functional impairment and poor HR-QoL, especially in physical components (P < 0.05).

Conclusion:

Various factors, especially longer disease duration and higher disease activity, were related to decreased hand and wrist AROMs, and thus causing functional impairment and poor HR-QoL in RA patients. Clinical physicians and medical faculties should pay more attention to disease activity and disease-related symptoms of these patients in order to maintain their activity of daily living (ADL) ability and improve HR-QoL.

References:

[1]Rheumatoid arthritis. Nat Rev Dis Primers. 2018;4:18002.

[2]Zhang L, Cao H, Zhang Q, Fu T, Yin R, Xia Y, et al. Motion analysis of the wrist joints in Chinese rheumatoid arthritis patients: a cross-sectional study. BMC Musculoskelet Disord. 2018;19(1):270.

Acknowledgements:

This work was funded by Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant/Award number: KYCX19_2071), National Natural Science Foundation of China (Grant/Award number: 81871278, Science and technology Project of Jiangsu Province (Grant/Award number: BE2018671)

Disclosure of Interests:

None declared

Biotransformation of rare earth oxide nanoparticles eliciting microbiota imbalance

Background

Disruption of microbiota balance may result in severe diseases in animals and phytotoxicity in plants. While substantial concerns have been raised on engineered nanomaterial (ENM) induced hazard effects (e.g., lung inflammation), exploration of the impacts of ENMs on microbiota balance holds great implications.

Results

This study found that rare earth oxide nanoparticles (REOs) among 19 ENMs showed severe toxicity in Gram-negative (G⁻) bacteria, but negligible effects in Gram-positive (G⁺) bacteria. This distinct cytotoxicity was disclosed to associate with the different molecular initiating events of REOs in G⁻ and G⁺ strains. La₂O₃ as a representative REOs was demonstrated to transform into LaPO₄ on G⁻ cell membranes and induce 8.3% dephosphorylation of phospholipids. Molecular dynamics simulations revealed the dephosphorylation induced more than 2-fold increments of phospholipid diffusion constant and an unordered configuration in membranes, eliciting the increments of membrane fluidity and permeability. Notably, the ratios of G⁻/G⁺ reduced from 1.56 to 1.10 in bronchoalveolar lavage fluid from the mice with La₂O₃ exposure. Finally, we demonstrated that both IL-6 and neutrophil cells showed strong correlations with G⁻/G⁺ ratios, evidenced by their correlation coefficients with 0.83 and 0.92, respectively.

Conclusions

This study deciphered the distinct toxic mechanisms of La₂O₃ as a representative REO in G⁻ and G⁺ bacteria and disclosed that La₂O₃-induced membrane damages of G⁻ cells cumulated into pulmonary microbiota imbalance exhibiting synergistic pulmonary toxicity. Overall, these findings offered new insights to understand the hazard effects induced by REOs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00410-5.

Multi-omics integration identifies key upstream regulators of pathomechanisms in hypertrophic cardiomyopathy due to truncating MYBPC3 mutations

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the cardiac muscle, frequently caused by mutations in MYBPC3. However, little is known about the upstream pathways and key regulators causing the disease. Therefore, we employed a multi-omics approach to study the pathomechanisms underlying HCM comparing patient hearts harboring MYBPC3 mutations to control hearts.

RESULTS

Using H3K27ac ChIP-seq and RNA-seq we obtained 9310 differentially acetylated regions and 2033 differentially expressed genes, respectively, between 13 HCM and 10 control hearts. We obtained 441 differentially expressed proteins between 11 HCM and 8 control hearts using proteomics. By integrating multi-omics datasets, we identified a set of DNA regions and genes that differentiate HCM from control hearts and 53 protein-coding genes as the major contributors. This comprehensive analysis consistently points toward altered extracellular matrix formation, muscle contraction, and metabolism. Therefore, we studied enriched transcription factor (TF) binding motifs and identified 9 motif-encoded TFs, including KLF15, ETV4, AR, CLOCK, ETS2, GATA5, MEIS1, RXRA, and ZFX. Selected candidates were examined in stem cell-derived cardiomyocytes with and without mutated MYBPC3. Furthermore, we observed an abundance of acetylation signals and transcripts derived from cardiomyocytes compared to non-myocyte populations.

CONCLUSIONS

By integrating histone acetylome, transcriptome, and proteome profiles, we identified major effector genes and protein networks that drive the pathological changes in HCM with mutated MYBPC3. Our work identifies 38 highly affected protein-coding genes as potential plasma HCM biomarkers and 9 TFs as potential upstream regulators of these pathomechanisms that may serve as possible therapeutic targets.

Microsatellite markers reveal polymorphisms at the 3′ untranslated region of the SLC11A1 gene in Zhongdian Yellow cattle (Bos taurus)

Solute carrier family 11-member A1 (SLC11A1) gene encodes natural macrophage resistance-associated protein which regulates activity of macrophages against intracellular pathogens. The objective of this study was to study the polymorphism in the microsatellites present at 3′ untranslated region (UTR) of the SLC11A1 gene in 113 Zhongdian Yellow cattle (Bos taurus). Using DNA bi-directional sequencing, we detected seven alleles (GT10–16) for the first microsatellite (MS1), five alleles (GT12–16) for MS2, and four alleles (GT4–7) for MS3. MS3 is studied for the first time and revealed four novel variants (alleles GT4–7). Alleles GT12 (45.1%), GT13 (59.3%), and GT5 (85.4%) were the most frequent alleles at MS1, MS2, and MS3, respectively, Genotypes G12/12, G13/13, and G5/5 had the highest frequency 0.239, 0.540, and 0.743 at MS1, MS2, and MS3, respectively. Haplotypic data revealed that GT12/GT13 was the most frequent haplotype observed followed by GT12/14 haplotype. Three nucleotide variations were observed in MS1 and MS2. Comparative analysis of GT12/GT12 and GT13/GT13 genotype with other bovine genotypes showed significant difference (P > 0.05). Our results suggest that the homozygous genotypes GT12/GT12 and GT13/GT13 in Zhongdian Yellow cattle might be related to disease resistance. The findings reported in this study would be helpful in cattle breeding programs.

Potential Unwinding of Double-Stranded DNA upon Binding to a Carbon Nitride Polyaniline (C3N) Nanosheet

Recently, carbon nitride polyaniline (C₃N) had attracted considerable attention from many scientific fields after its successful synthesis. However, thus far, limited efforts were devoted to reveal its potential effect to biomolecules, which correlated intimately with its further utilization. In this study, by using a molecular dynamics (MD) simulation approach, we investigated in detail the interaction between C₃N and a double-stranded DNA (dsDNA) segment to expose the underlying biological effect of C₃N to dsDNA and the corresponding molecular basis. MD simulation results demonstrated that dsDNA presented serious damages upon adsorption onto a C₃N nanosheet with the terminal base pairs denaturized, unwound, and directly packing on the C₃N surface, which implied that C₃N was potentially deleterious to biomolecules. This binding/unwinding process was mainly guided by a combination of van der Waals and π-π stacking interactions together with a continuous lateral migration of dsDNA. Moreover, the nanoscale dewetting also played an important role during the adsorption. These findings revealed the potential bio-effect of the C₃N nanomaterial and its molecular mechanism, which might benefit the future applications of C₃N-based nanostructures.

Restricted binding of a model protein on C3N4 nanosheets suggests an adequate biocompatibility of the nanomaterial

The fixed binding pattern of protein adsorption to C₃N₄ plays a major role in the nanomaterial biocompatibility, which results from the inherent porous surface structure.

Molecular cloning, tissue expression and polymorphism analysis of the Caveolin-3 gene in ducks

1. Duck meat is considered a delicacy, but choosing the best meat is problematic. Caveolin-3 (CAV-3) is a muscle-specific protein marker in animals. The goal of the current study was to detect the characteristics of CAV-3 gene in ducks. 2. Full-length CAV-3 was acquired from ducks (Anas platyrhynchos) using reverse transcriptase PCR and rapid amplification of cDNA ends. DNAMAN software was used for homology comparisons. Quantitative reverse transcription-PCR, PCR-single-strand conformation polymorphism, and sequencing were used to determine CAV-3 expression and polymorphism of a single nucleotide, respectively. The study examined four types of ducks, including Jinding, Chaohu, Cherry Valley, and Gaoyou ducks. 3. The study acquired 1066 bp of CAV-3 cDNA sequences, including a 456 bp complete open reading frame encoding 151 amino acids. Both coding sequences (CDSs) and translated amino acids exhibited highest homology with Gallus gallus (CDS homology 91.67%, amino acids 94.04%), followed by mammalian species (CDS homology 79.0%, amino acids 78.0%). Single nucleotide polymorphism analysis revealed five mutations in exons (A489G, G501A, A557G, T563A, and A602G), and a C805T mutation in an intron. Among amplified polymorphic loci detected using primer 2, allele frequency was higher for A (489A501G507A563T602A) than B (489G501G507G563T602C) or C (489G501A507G563A602C). The highest occurred in Cherry Valley ducks (0.7587). Using primer 4, the M allele frequency was higher than that of the N allele. CAV-3 was most highly expressed in the heart, followed by skeletal muscles. Additionally, CAV-3 had higher expression in heart and breast muscle of overfed Muscovy ducks than control ducks, but no difference was seen in thigh muscle. 4. CAV-3 in ducks had the highest homology with Gallus gallus CAV-3, and it could be used as a marker for muscle quality in ducks.

Effects of glucocorticoids on osteoporosis in rheumatoid arthritis: a systematic review and meta-analysis

We evaluated the effects of glucocorticoids on bone mineral density (BMD), and prevalence of osteoporosis and fracture in rheumatoid arthritis (RA) by meta-analysis. Until June 26, 2019, we conducted a systematic literature search in EMBASE, Web of science, PubMed, and Cochrane Library to obtain BMD and the prevalence of osteoporosis and fracture in glucocorticoid-treated subjects with RA. The BMD of the treatment and control groups were analyzed by meta-analysis (Stata. version 15), and the 95% confidence interval (CI) was calculated. We identified 15 observational studies, including 46,711 RA subjects and 857 healthy controls. The BMD of the lumbar spine (- 0.038 g/cm²; CI, - 0.052, - 0.024) and femoral neck (- 0.017 g/cm²; - 0.030, - 0.003) in RA treated with glucocorticoids were significantly lower than those in RA controls. Compared with healthy control group, the BMD of the lumbar spine (- 0.094 g/cm²; - 0.126, - 0.061) and femoral neck (- 0.097 g/cm², - 0.109, - 0.085) of RA treated with glucocorticoids decreased more significantly. The prevalence of osteoporosis in whole body, spine, and femur was 38.6% (0.305, 0.466), 32.9% (0.277, 0.381), and 21.7% (0.106, 0.328), respectively. And the prevalence of vertebral fracture was 13.0% (0.058, 0.203). Glucocorticoids may lead to a decline in skeletal health in subjects with RA, especially in vertebral and femoral BMD, compared with normal people or RA without glucocorticoid therapy. Meanwhile, osteoporosis and fractures were also common. Therapeutic measures should be targeted at individuals, which needs further study. Through meta-analysis, we found that glucocorticoids have some negative effects on the bone health of subjects with rheumatoid arthritis. Therefore, when using glucocorticoids to treat rheumatoid arthritis, we should take strategic measures to prevent the decline of bone quality.

AB1331-HPR ACTIVE DISEASE ACTIVITY IN ANKYLOSIS SPONDYLITIS: WORSE OUTCOMES AND POORER HR-QOL

Background:

Ankylosing spondylitis (AS) is a chronic inflammatory disease that mainly affects the sacroiliac joints and the spine, resulting in decline in quality of life[1,2]. Poor QoL is significantly related to high disease activity[3]. However, there is no systematic report on which prognosis indicators are affected by disease activity in AS patients.

Objectives:

This study aimed to evaluate the patient-reported outcome measures and health-related quality of life (HR-QoL) in AS patients defined on the basis of the Bath Spondylitis Ankylosing Disease Activity Index (BASDAI).

Methods:

204 AS patients were involved in this study. A serious of questionnaires were used to overall assess AS patients, which include: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI), the 10 cm Visual Analog Scale (VAS), the Self-Rating Anxiety Scale (SAS), the Self-Rating Depression Scale (SDS), the Pittsburgh Sleep Quality Index (PSQI), the Health Assessment Questionnaire-Disability Index (HAQ-DI), the Fatigue Severity Scale(FSS) and the Short Form 36 Health Survey (SF-36). Independent samples t-test, Mann–Whitney U-test, Chi-square analysis and Pearson /Spearman correlation were used to analyze the data.

Results:

The results demonstrated 31.4% AS patients were in active disease activity stage. Active AS patients were older, unemployed, and had less exercise therapy than stable AS patients. Besides, AS patients with active disease activity presented more severe pain(P<0.001), poor physical function(P<0.001) and spinal mobility(P<0.001). They were more anxious(P<0.001), depressed(P<0.001) and had more sleep disturbance(P=0.001). Compared with active AS patients, stable AS patients had more leukocytes(P=0.040), lymphocytes(P=0.002), erythrocytes(P=0.001) and hemoglobin(P<0.001). Active disease activity had a significant impact on all dimensions of quality of life in AS patients(P<0.001).

Conclusion:

These findings suggested that medical personnel should pay more attention to active AS patients and make effective interventions to improve quality of life.

References:

[1]Exarchou S, Lindstrom U, Askling J, Eriksson JK, Forsblad-d’Elia H, Neovius M, Turesson C, Kristensen LE, Jacobsson LT (2015) The prevalence of clinically diagnosed ankylosing spondylitis and its clinical manifestations: a nationwide register study. Arthritis research & therapy 17:118. doi:10.1186/s13075-015-0627-0

[2]Qian Q, Xu X, He H, Ji H, Zhang H, Ding Y, Dai SM, Zou Y, Zhu Q, Yang C, Ye S, Jiang L, Tang JP, Tong Q, He D, Zhao D, Li Y, Ma Y, Zhou J, Yuan Z, Zhang J, Jin L, Zhou X, Reveille JD, Zou H, Wang J (2017) Clinical patterns and characteristics of ankylosing spondylitis in China. Clinical rheumatology 36 (7):1561-1568. doi:10.1007/s10067-017-3660-3

[3]Huang JC, Qian BP, Qiu Y, Wang B, Yu Y, Zhu ZZ, Hu J, Qu Z (2017) Quality of life and correlation with clinical and radiographic variables in patients with ankylosing spondylitis: a retrospective case series study. BMC musculoskeletal disorders 18 (1):352. doi:10.1186/s12891-017-1711-1

Acknowledgments:

Thanks to all the authors for their efforts and thanks to all members of the Department of Rheumatology of Affiliated Hospital of Nantong University for their helpfulness in the acquisition of data.

Disclosure of Interests:

None declared

THU0044 SINGLE CELL ANALYSIS OF BONE MARROW AND PERIPHERAL ALTERED B CELL DIFFERENTIATION IN PATIENTS WITH ACTIVE SLE AND THE MECHANISM OF ABNORMAL EARLY B CELL DEVELOPMENT

Background:

B cell differentiation and dysfunction play a key role in the pathogenesis of Systemic lupus erythematosus (SLE). Bone marrow (BM) is the development organ of B cells, and also the home and residence place of plasma cells and memory B cells. However, there is a lack of studies on B cells in BM with lupus.

Objectives:

To map the development of BM and peripheral B cells and investigate the mechanism of abnormal early B cell development in SLE.

Methods:

A total of 11 SLE patients and 5 age- and sex-matched controls were recruited.BM and peripheral B cell subsets were measured by flow cytometry. sorting-purified B cell subsets were subject toSingle-cell RNA sequencing (scRNA-seq) and functional studies. Plasma cytokines and secreted immunoglobulins were detected by Luminex or ELISA. Disease activity of SLE patients was measured using the SLE Disease Activity Index (SLEDAI).

Results:

In the present study, we find out that the percentage of monocytes in MNC (p=0.070) and plasma cells(p=0.001)in CD19+ were significantly decreased in BM of SLE, compared to healthy controls. While, SLE patients had increased T%MNC(p=0.008) and B%CD19+(p=0.002) in BM that controls. In detail, the B cell subsets of bone marrow in patients with active lupus (SLEDAI≥8 score) were seriously disordered, showing the increasing T%MNC(p=0.049), propre-B%CD19+ (p=0.006)and immature B cell%CD19+ (p=0.010) than healthy donors. propre-B%CD19+ exhibited good relationship with SLEDAI. By integrating single B cell expression profiling and repertoire analysis, we map the development of B cells in BM and peripheral and pathogenic characteristics of early B cells, especially propre-B.

Conclusion:

These findings demonstrated that early B cells in BM, especially propre-B are abnormally differentiated with dysregulations. BM is an important organ targeted by SLE. This studyis not only to clarify the internal mechanism of the disorder of differentiation of B cells, but also to provide new clues for the targeted diagnosis and treatment of SLE.

References:

[1]Palanichamy, A., et al.,Neutrophil-mediated IFN activation in the bone marrow alters B cell development in human and murine systemic lupus erythematosus.J Immunol, 2014.192(3): p. 906-18.

[2]Papadaki, H.A., J.C. Marsh, and G.D. Eliopoulos,Bone marrow stem cells and stromal cells in autoimmune cytopenias.Leuk Lymphoma, 2002.43(4): p. 753-60.

[3]Karrar, S. and D.S. Cunninghame Graham,Abnormal B Cell Development in Systemic Lupus Erythematosus: What the Genetics Tell Us.Arthritis Rheumatol, 2018.70(4): p. 496-507.

[4]Woods, M., Y.R. Zou, and A. Davidson,Defects in Germinal Center Selection in SLE.Front Immunol, 2015.6: p. 425.

[5]Upregulation of p16INK4A promotes cellular senescence of bone marrow-derived mesenchymal stem cells from systemic lupus erythematosus patients.Cell Signal, 2012.24(12): p. 2307-14.

Disclosure of Interests:

None declared

AB1330-HPR ASSOCIATION OF INTERSTITIAL LUNG DISEASE AND QUALITY OF LIFE IN CHINESE RHEUMATOID ARTHRITIS

Background:

The health-related quality of life (HRQL) of patients with rheumatoid arthritis associated interstitial lung disease (RA-ILD) is less concerned(1). This study hypothesized that HRQL of such patients decreased.

Objectives:

The aim of this study was to assess the difference in HRQL between RA with and without ILD, and to predict risk factors of HRQL in Chinese RA-ILD.

Methods:

A cross-sectional survey of RA-ILD patients included socio-demographic characteristics, clinical variables, psychological factors and HRQL. Data were analyzed by Student’s t or chi-square test. Linear regression analysis was used to investigate the predictors of HRQL in RA-ILD.

Results:

The data showed that 35.17% (51/145) of RA patients had ILD. There are significant differences in age, sex, smoking history, disease duration and activity between RA with and without ILD. HRQL of RA-ILD was impaired. Physical component score (PCS) of patients with RA-ILD was also worse than that of RA without ILD (48.91±2.48 vs. 50.80±2.55). Linear regression analysis showed that DAS28 and fatigue were risk factors for PCS in patients with RA-ILD, while depression and rural residence were risk factors for mental components summary in Table 1.

Table 1.

Stepwise multiple linear regression analysis of PCS and MCS in RA-ILD

PredictorsBSEtP95%CIPCSDAS28-0.7770.227-3.4250.001-1.236,-0.319Fatigue-0.6550.206-3.1770.003-1.071, -0.238MCSDepression2.1880.6693.2720.0020.836, 3.539Rural residents-1.6090.756-2.1280.040-3.137,-0.081

Footnotes: CI=Confidence interval. PCS=Physical component score; MCS=Mental component score; DAS28=28-joint disease activity score.

Conclusion:

Compared with RA without ILD, HRQL of patients with RA-ILD was significantly impaired. Disease activity, fatigue, depression and rural residence were independent predictors of HRQL in Chinese RA-ILD.

References:

[1]Zamora-Legoff JA, Krause ML, Crowson CS, Ryu JH, Matteson EL. Patterns ofinterstitial lung disease and mortality in rheumatoid arthritis. Rheumatology (Oxford, England). 2017;56(3):344-50.

Disclosure of Interests:

None declared

SAT0625-HPR FATIGUE AND CONTRIBUTING FACTORS IN CHINESE PATIENTS WITH ANKYLOSING SPONDYLITIS

Background:

Ankylosing spondylitis (AS) is a systemic chronic inflammatory disease, which most likely occurs in young men. It mainly affects sacroiliac joints, axial skeleton, thoracic cage and seriously decreasing quality of life in AS patients[1,2]. In recent years, fatigue of AS patients has been paid more and more attention[3]. Fatigue is a complex feeling, diseased individuals describe fatigue as a sense of tiredness at rest, exhaustion with activity, lack of energy which affects daily work, inertia or lack of endurance, or as loss of vitality. It has been confirmed that fatigue is not only a symptom but may also be quantified by fatigue scores and can be modified by various measures depending on the underlying cause[4]. However, there has been no study about fatigue in AS patients in China.

Objectives:

This study aimed to evaluate the predictors of fatigue and the effects of fatigue on HR-QoL among patients with AS.

Methods:

A total of 150 AS patients were involved in the study. A series of questionnaires included: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI), the 10 cm Visual Analog Scale (VAS), the Self-Rating Anxiety Scale (SAS), the Self-Rating Depression Scale (SDS), the Pittsburgh Sleep Quality Index (PSQI), the Health Assessment Questionnaire-Disability Index (HAQ-DI), the Short Form 36 Health Survey (SF-36) and the Fatigue Severity Scale(FSS). Independent samples t-test, Mann–Whitney U-test, Chi-square analysis, Pearson /Spearman correlation and binary logistic regression were used to analyze the data.

Results:

The results demonstrated that 48.7% individuals with AS suffered from fatigue. Compared with AS patients without fatigue, AS patients with fatigue showed higher WHR(P<0.05), increased BASDAI (P<0.01) and poorer BASFI (P<0.05). Meanwhile, AS patients with fatigue tended to have more severe pain(P<0.05), higher degree of anxiety(P=0.001), more serious functional disability(P=0.001) and worse sleep quality(P=0.001). Binary logistic regression indicated that WHR (OR=1.78,P<0.05), BASDAI (OR=1.34,P=0.01), sleep disturbance (OR=2.35,P<0.05) were independent predictors of fatigue in AS patients. Additionally, the occurrence of fatigue significantly reduced the quality of life in AS patients both physically and psychologically.

Conclusion:

These findings suggested that medical personnel should pay more attention to AS patients with fatigue and take effective measures to relieve fatigue.

References:

[1]Law L, Beckman Rehnman J, Deminger A, Klingberg E, Jacobsson LTH, Forsblad-d’Elia H (2018) Factors related to health-related quality of life in ankylosing spondylitis, overall and stratified by sex. Arthritis research & therapy 20 (1):284. doi:10.1186/s13075-018-1784-8

[2]Hanson A, Brown MA (2017) Genetics and the Causes of Ankylosing Spondylitis. Rheumatic diseases clinics of North America 43 (3):401-414. doi:10.1016/j.rdc.2017.04.006

[3]Ulus Y, Akyol Y, Bilgici A, Kuru O (2019) Association of work instability with fatigue and emotional status in patients with ankylosing spondylitis: comparison with healthy controls. Clinical rheumatology 38 (4):1017-1024. doi:10.1007/s10067-018-4366-x

[4]Finsterer J, Mahjoub SZ (2014) Fatigue in healthy and diseased individuals. The American journal of hospice & palliative care 31 (5):562-575. doi:10.1177/1049909113494748

Acknowledgments:

Thanks to all the authors for their efforts and thanks to all members of the Department of Rheumatology of Affiliated Hospital of Nantong University for their helpfulness in the acquisition of data.

Disclosure of Interests:

None declared