Placenta-derived mesenchymal stem cells promote diabetic wound healing via exosomal protein interaction networks.

There is a lack of effective treatment options for diabetic refractory wounds, which presents a critical clinical issue that needs to be addressed urgently. Our research has demonstrated that human placenta-derived mesenchymal stem cells (plaMSCs) facilitate the migration and proliferation of HaCat cells, thereby enhancing diabetic wound healing primarily via the exosomes derived from plaMSCs (plaMSCs-Ex). Using label-free proteomics, plaMSCs and their exosomes were analysed for proteome taxonomic content in order to explore the underlying effective components mechanism of plaMSCs-Ex in diabetic wound healing. Differentially expressed proteins enriched in plaMSCs-Ex were identified and underwent bioinformatics analysis including GO annotation, KEGG pathway enrichment, gene set enrichment analysis (GSEA) and protein-protein interaction analysis (PPI). Results showed that the proteins enriched in plaMSCs-Ex are significantly involved in extracellular matrix organisation, epithelium morphogenesis, cell growth, adhesion, proliferation and angiogenesis. PPI analysis filtered 2 wound healing-related clusters characterised by hub proteins such as POSTN, FN1, SPARC, TIMP1, SERPINE1, LRP1 and multiple collagens. In brief, the exosomal proteins derived from plaMSCs reveal diverse functions of regeneration and tissue remodelling based on proteomics analysis and potentially play a role in diabetic wound healing.

Alkaline phosphatase-activated prodrug system based on a bifunctional CuO NP tandem nanoenzyme for on-demand bacterial inactivation and wound disinfection.

Nanozymes are promising antimicrobials, as they produce reactive oxygen species (ROS). However, the intrinsic lack of selectivity of ROS in distinguishing normal flora from pathogenic bacteria deprives nanozymes of the necessary selectivities of ideal antimicrobials. Herein, we exploit the physiological conditions of bacteria (high alkaline phosphatase (ALP) expression) using a novel CuO nanoparticle (NP) nanoenzyme system to initiate an ALP-activated ROS prodrug system for use in the on-demand precision killing of bacteria. The prodrug strategy involves using 2-phospho-L-ascorbic acid trisodium salt (AAP) that catalyzes the ALP in pathogenic bacteria to generate ascorbic acid (AA), which is converted by the CuO NPs, with intrinsic ascorbate oxidase- and peroxidase-like activities, to produce ROS. Notably, the prodrug system selectively kills Escherichia coli (pathogenic bacteria), with minimal influence on Staphylococcus hominis (non-pathogenic bacteria) due to their different levels of ALP expression. Compared to the CuO NPs/AA system, which generally depletes ROS during storage, CuO NPs/AAP exhibits a significantly higher stability without affecting its antibacterial activity. Furthermore, a rat model is used to indicate the applicability of the CuO NPs/AAP fibrin gel in wound disinfection in vivo with negligible side effects. This study reveals the therapeutic precision of this bifunctional tandem nanozyme platform against pathogenic bacteria in ALP-activated conditions.

Imbalance of programmed cell death patterns mediated by dendritic cell subsets in systemic lupus erythematosus and lupus nephritis. / æ ‘çªçŠ¶ç»†èƒžäºšç¾¤ä»‹å¯¼ç³»ç»Ÿæ€§çº¢æ–‘ç‹¼ç–®å’Œç‹¼ç–®è‚¾ç‚Žçš„ç¨‹åºæ€§ç»†èƒžæ­»äº¡æ¨¡å¼å¤±è¡¡ï¼ˆè‹±æ–‡ï¼‰.

OBJECTIVES: Abnormal programmed cell death in immune cells is associated with autoimmune diseases, but the patterns of programmed cell death in systemic lupus erythematosus (SLE) and especially lupus nephritis (LN) remain unclear. This study aims to explore the association between SLE, LN, and immune cell death patterns. METHODS: Bulk RNA sequencing (bulk RNA-seq) and single-cell RNA sequencing (scRNA-seq) data were downloaded from the Gene Expression Omnibus (GEO) database. Bioinformatic analysis was conducted to explore the expression levels of genes related to 3 cell death patterns in peripheral blood mononuclear cells of SLE patients. Key cell subsets involved in the imbalance of cell death patterns were identified through scRNA-seq. Immunofluorescence was used to detect the expression levels of receptor interacting serine/threonine kinase 3 (RIPK3), mixed-lineage kinase domain-like protein (MLKL), phosphorylated MLKL (pMLKL), caspase 1 (CASP1), CD1c molecule (CD1C), C-type lectin domain containing 9A (CLEC9A), and X-C motif chemokine receptor 1 (XCR1) in dendritic cells (DC). scRNA-seq was performed on kidney tissues collected from LN patients and healthy controls (HC) at the Third Xiangya Hospital of Central South University, followed by bioinformatic analysis to identify key cell subsets involved in the imbalance of cell death patterns. Pseudotime analysis and ligand-receptor analysis were used to explore the differentiation direction and cell communication of different DC subsets. Transient transfection was used to transfect RAW264.7 cells with empty plasmid, empty plasmid+dsDNA (HSV-DNA), empty plasmid+200 µmol/L tert-butyl hydroperoxide (TBHP), stimulator of interferon genes (STING) shRNA plasmid, STING shRNA plasmid+dsDNA (HSV-DNA), and STING shRNA plasmid+200 µmol/L TBHP. Annexin V-mCherry and SYTOX Green staining were used to detect cell death in each group. Western blotting was used to detect the activation of CASP1, gasdermin D (GSDMD), RIPK3, and MLKL in each group. RESULTS: Bioinformatic analysis showed an imbalance in 3 cell death patterns in SLE and LN patients: Pro-inflammatory pyroptosis and necroptosis were activated, while anti-inflammatory apoptosis was inhibited. The key cell subsets involved were DC subsets, particularly focusing on CLEC9A+cDC1. Immunofluorescence results showed that the expression levels of RIPK3, MLKL, and CASP1 in DCs were higher in the SLE group compared to the HC group. pMLKL and CASP1 expression levels in renal cDC1 marked by CLEC9A and XCR1 were higher in the LN group than in the HC group. Pseudotime analysis and ligand-receptor analysis suggested that the CLEC9A+cDC1 subset in LN kidney tissues originated from peripheral circulation. Annexin V-mCherry and SYTOX Green staining results showed that the number of dead cells decreased in the STING shRNA transfection group compared to the empty plasmid group in RAW264.7 cells. Western blotting results showed that the activation of CASP1, GSDMD, RIPK3, and MLKL was decreased in the STING shRNA transfection group compared to the empty plasmid group. CONCLUSIONS: This study provides novel insights into the role of CLEC9A+cDC1 in the imbalance of cell death patterns in SLE and LN.

Intrahepatic macrophage reprogramming associated with lipid metabolism in hepatitis B virus-related acute-on-chronic liver failure.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a severe syndrome with high short-term mortality, but the pathophysiology still remains largely unknown. Immune dysregulation and metabolic disorders contribute to the progression of ACLF, but the crosstalk between immunity and metabolism during ACLF is less understood. This study aims to depict the immune microenvironment in the liver during ACLF, and explore the role of lipid metabolic disorder on immunity. METHODS: Single-cell RNA-sequencing (scRNA-seq) was performed using the liver non-parenchymal cells (NPCs) and peripheral blood mononuclear cells (PBMCs) from healthy controls, cirrhosis patients and ACLF patients. A series of inflammation-related cytokines and chemokines were detected using liver and plasma samples. The lipid metabolomics targeted free fatty acids (FFAs) in the liver was also detected. RESULTS: The scRNA-seq analysis of liver NPCs showed a significant increase of monocytes/macrophages (Mono/Mac) infiltration in ACLF livers, whereas the resident Kupffer cells (KCs) were exhausted. A characterized TREM2+ Mono/Mac subpopulation was identified in ACLF, and showed immunosuppressive function. Combined with the scRNA-seq data from PBMCs, the pseudotime analysis revealed that the TREM2+ Mono/Mac were differentiated from the peripheral monocytes and correlated with lipid metabolism-related genes including APOE, APOC1, FABP5 and TREM2. The targeted lipid metabolomics proved the accumulation of unsaturated FFAs associated with α-linolenic acid (α-LA) and α-LA metabolism and beta oxidation of very long chain fatty acids in the ACLF livers, indicating that unsaturated FFAs might promote the differentiation of TREM2+ Mono/Mac during ACLF. CONCLUSIONS: The reprogramming of macrophages was found in the liver during ACLF. The immunosuppressive TREM2+ macrophages were enriched in the ACLF liver and contributed to the immunosuppressive hepatic microenvironment. The accumulation of unsaturated FFAs in the ACLF liver promoted the reprogramming of the macrophages. It might be a potential target to improve the immune deficiency of ACLF patients through regulating lipid metabolism.

The long non-coding RNA KLF3-AS1/miR-10a-3p/ZBTB20 axis improves the degenerative changes in human nucleus pulposus cells.

Excessive apoptosis of intervertebral disc cells, namely nucleus pulposus (NP) cells, results in decreased cell density and extracellular matrix (ECM) catabolism, hence leading to intervertebral disc degeneration (IVDD). As a cell model in the present study, a commercially available human NP cell line was utilized. Long noncoding RNAs and microRNAs may regulate the proliferation or apoptosis of human NP cells, hence exerting a significant influence on the occurrence of IVDD. KLF3-AS1 was discovered to be abnormally downregulated in IVDD tissues. Overexpression of KLF3-AS1 enhanced NP cell viability, prevented cell apoptosis, boosted ECM synthesis, and lowered MMP-13 and ADAMTS4 levels. ZBTB20 and KLF3-AS1 were co-expressed in IVDD; ZBTB20 overexpression had similar effects on NP cells, ECM production, and MMP-13 and ADAMTS4 levels as KLF3-AS1 overexpression. miR-10a-3p may target KLF3-AS1 and ZBTB20 and inhibit the expression of ZBTB20. Inhibition of miR-10a-3p enhanced NP cell viability, reduced apoptosis, and enhanced ECM synthesis. KLF3-AS1 overexpression increased ZBTB20 expression, whereas miR-10a-3p overexpression decreased ZBTB20 expression; miR-10a-3p overexpression reduced the effects of KLF3-AS1 on ZBTB20. Overexpression of miR-10a-3p consistently decreased the effects of KLF3-AS1 overexpression on NP cell survival, apoptosis, and ECM synthesis. In conclusion, KLF3-AS1 overexpression may ameliorate degenerative NP cell alterations through the miR-10a-3p/ZBTB20 axis.

A meta-validated immune infiltration-related gene model predicts prognosis and immunotherapy sensitivity in HNSCC.

BACKGROUND: Tumor microenvironment (TME) is of great importance to regulate the initiation and advance of cancer. The immune infiltration patterns of TME have been considered to impact the prognosis and immunotherapy sensitivity in Head and Neck squamous cell carcinoma (HNSCC). Whereas, specific molecular targets and cell components involved in the HNSCC tumor microenvironment remain a twilight zone. METHODS: Immune scores of TCGA-HNSCC patients were calculated via ESTIMATE algorithm, followed by weighted gene co-expression network analysis (WGCNA) to filter immune infiltration-related gene modules. Univariate, the least absolute shrinkage and selection operator (LASSO), and multivariate cox regression were applied to construct the prognostic model. The predictive capacity was validated by meta-analysis including external dataset GSE65858, GSE41613 and GSE686. Model candidate genes were verified at mRNA and protein levels using public database and independent specimens of immunohistochemistry. Immunotherapy-treated cohort GSE159067, TIDE and CIBERSORT were used to evaluate the features of immunotherapy responsiveness and immune infiltration in HNSCC. RESULTS: Immune microenvironment was significantly associated with the prognosis of HNSCC patients. Total 277 immune infiltration-related genes were filtered by WGCNA and involved in various immune processes. Cox regression identified nine prognostic immune infiltration-related genes (MORF4L2, CTSL1, TBC1D2, C5orf15, LIPA, WIPF1, CXCL13, TMEM173, ISG20) to build a risk score. Most candidate genes were highly expressed in HNSCC tissues at mRNA and protein levels. Survival meta-analysis illustrated high prognostic accuracy of the model in the discovery cohort and validation cohort. Higher proportion of progression-free outcomes, lower TIDE scores and higher expression levels of immune checkpoint genes indicated enhanced immunotherapy responsiveness in low-risk patients. Decreased memory B cells, CD8+ T cells, follicular helper T cells, regulatory T cells, and increased activated dendritic cells and activated mast cells were identified as crucial immune cells in the TME of high-risk patients. CONCLUSIONS: The immune infiltration-related gene model was well-qualified and provided novel biomarkers for the prognosis of HNSCC.

Identification of the shared genes and immune signatures between systemic lupus erythematosus and idiopathic pulmonary fibrosis.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disorder which could lead to inflammation and fibrosis in various organs. Pulmonary fibrosis is a severe complication in patients with SLE. Nonetheless, SLE-derived pulmonary fibrosis has unknown pathogenesis. Of pulmonary fibrosis, Idiopathic pulmonary fibrosis (IPF) is a typicality and deadly form. Aiming to investigate the gene signatures and possible immune mechanisms in SLE-derived pulmonary fibrosis, we explored common characters between SLE and IPF from Gene Expression Omnibus (GEO) database. RESULTS: We employed the weighted gene co-expression network analysis (WGCNA) to identify the shared genes. Two modules were significantly identified in both SLE and IPF, respectively. The overlapped 40 genes were selected out for further analysis. The GO enrichment analysis of shared genes between SLE and IPF was performed with ClueGO and indicated that p38MAPK cascade, a key inflammation response pathway, may be a common feature in both SLE and IPF. The validation datasets also illustrated this point. The enrichment analysis of common miRNAs was obtained from the Human microRNA Disease Database (HMDD) and the enrichment analysis with the DIANA tools also indicated that MAPK pathways' role in the pathogenesis of SLE and IPF. The target genes of these common miRNAs were identified by the TargetScan7.2 and a common miRNAs-mRNAs network was constructed with the overlapped genes in target and shared genes to show the regulated target of SLE-derived pulmonary fibrosis. The result of CIBERSORT showed decreased regulatory T cells (Tregs), naïve CD4+ T cells and rest mast cells but increased activated NK cells and activated mast cells in both SLE and IPF. The target genes of cyclophosphamide were also obtained from the Drug Repurposing Hub and had an interaction with the common gene PTGS2 predicted with protein-protein interaction (PPI) and molecular docking, indicating its potential treatment effect. CONCLUSIONS: This study originally uncovered the MAPK pathway, and the infiltration of some immune-cell subsets might be pivotal factors for pulmonary fibrosis complication in SLE, which could be used as potentially therapeutic targets. The cyclophosphamide may treat SLE-derived pulmonary fibrosis through interaction with PTGS2, which could be activated by p38MAPK.

Association between serum soluble α-klotho and bone mineral density (BMD) in middle-aged and older adults in the United States: a population-based cross-sectional study.

BACKGROUND: Osteoporosis is a degenerative disease defined by low bone mineral density, has a high prevalence, and causes fractures at multiple sites throughout the body, greatly affecting the quality of patients. α-Klotho is an endocrine factor involved in the regulation of various metabolic processes in humans, and its role in bone metabolism has attracted widespread attention. The relationship between α-klotho and bone mineral density has not been uniformly recognized, and no large-scale correlation analysis has been conducted in the middle-aged and elderly population. OBJECTIVE: To determine the relationship between α-klotho and bone mineral density in middle-aged and elderly people. METHODS: Population data of 3120 individuals aged 40-79 years were obtained from the NHANES database for the period 2011-2016. Regression analysis was performed using a general linear model with serum α-klotho as the independent variable and total bone mineral density, thoracic bone mineral density, lumbar bone mineral density, pelvic bone mineral density, and trunk bone mineral density as the dependent variables, respectively. The generalized additive model was also used for smoothing curve fitting and threshold effect analysis. RESULTS: Serum α-klotho was positively correlated with total bone mineral density at lg (Klotho) < 2.97 and with thoracic bone mineral density at lg (Klotho) > 2.69 (ß = 0.05, p = 0.0006), and negatively correlated (ß = -0.27, p = 0.0341) with lumbar bone mineral density at lg (Klotho) < 2.69. It also positively correlated with trunk bone mineral density (ß = 0.027, p = 0.03657) and had no segmental effect but did not correlate with pelvic bone mineral density. The positive association of serum α-klotho with those aged 40-49 years, female, non-Hispanic White, and without hypertension was clearer. In the population with diabetes, a significantly positive association between total (ß = 0.15, p = 0.01), thoracic (ß = 0.23, p = 0.0404), and lumbar (ß = 0.22, p = 0.0424) bone mineral density and α-klotho was observed. CONCLUSIONS: α-Klotho has different relationships with total, thoracic, lumbar, and trunk bone mineral density. Among them, the positive correlation between α-klotho and trunk bone mineral density is more valuable for predicting osteoporosis. The significant effect of α-klotho on bone mineral density in diabetes patients suggests its potential as a predictive marker of diabetes progression.

Multivalley Superconductivity in Monolayer Transition Metal Dichalcogenides.

In transition metal dichalcogenides (TMDs), Ising superconductivity with an antisymmetric spin texture on the Fermi surface has attracted wide interest due to the exotic pairing and topological properties. However, it is not clear whether the Q valley with a giant spin splitting is involved in the superconductivity of heavily doped semiconducting 2H-TMDs. Here by taking advantage of a high-quality monolayer WS2 on hexagonal boron nitride flakes, we report an ionic-gating induced superconducting dome with a record high critical temperature of ∼6 K, accompanied by an emergent nonlinear Hall effect. The nonlinearity indicates the development of an additional high-mobility channel, which (corroborated by first principle calculations) can be ascribed to the population of Q valleys. Thus, multivalley population at K and Q is suggested to be a prerequisite for developing superconductivity. The involvement of Q valleys also provides insights to the spin textured Fermi surface of Ising superconductivity in the large family of transition metal dichalcogenides.

CX3CR1 regulates the development of renal interstitial fibrosis through macrophage polarization. / CX3CR1通过调控巨噬细胞极化影响肾间质纤维化.

OBJECTIVES: The binding of CX3C chemokine receptor 1 (CX3CR1) and its unique ligand CX3C chemokine ligand 1 (CX3CL1) can promote the migration of inflammatory cells to the lesion and affect the progression of renal interstitial fibrosis, but the underlying mechanisms remain unclear. This study aims to investigate whether CX3CR1 affects renal interstitial fibrosis by macrophage polarization. METHODS: A mouse model of renal interstitial fibrosis was established by unilateral ureteral obstruction (UUO). C57/B6 mice were divided into a CX3CR1 inhibitor group (injected with CX3CR1 inhibitor AZD8797) and a model group (injected with physiological saline). After continuous intraperitoneal injection for 5 days, the ligated lateral kidneys of mice were obtained on the 7th day. Hematoxylin and eosin (HE) staining and Masson staining were used to observe the infiltration of inflammatory cells and the collagen fiber deposition in renal interstitium, respectively. The mRNA and protein expressions of CX3CR1, alpha-smooth muscle actin (α-SMA) and fibronectin (FN) in the kidneys were detected by reverse transcription PCR (RT-PCR) and Western blotting, respectively. Differentially expressed genes in kidney of the 2 groups were identified by whole genome sequencing and the differential expression of arginase-1 (Arg-1) was verified by RT-PCR. Flow cytometry was used to detect the proportion of M2 type macrophages in kidneys of the 2 groups. RESULTS: The infiltration of inflammatory cells and the collagen fiber deposition in renal interstitium were significantly reduced in the CX3CR1 inhibitor group. The mRNA and protein levels of CX3CR1 and the mRNA levels of α-SMA and FN in the CX3CR1 inhibitor group were significantly lower than those of the model group (all P<0.05). Whole genome sequencing showed that the top 5 differentially expressed genes in kidney of the 2 groups were Ugt1a6b, Serpina1c, Arg-1, Retnla, and Nup62. RT-PCR verified that the expression level of Arg-1 in kidney of the CX3CR1 inhibitor group was significantly higher than that of the model group (P<0.001). Flow cytometry showed that the proportion of Arg1+CD206+M2 macrophages in kidney of the CX3CR1 inhibitor group was significantly higher than that of the model group (P<0.01). CONCLUSIONS: Inhibiting CX3CR1 can effectively prevent the progression of renal interstitial fibrosis. The mechanism may be related to macrophage polarization towards M2 type and upregulation of Arg-1 expression.

Models to predict the short-term survival of acute-on-chronic liver failure patients following liver transplantation.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is featured with rapid deterioration of chronic liver disease and poor short-term prognosis. Liver transplantation (LT) is recognized as the curative option for ACLF. However, there is no standard in the prediction of the short-term survival among ACLF patients following LT. METHOD: Preoperative data of 132 ACLF patients receiving LT at our center were investigated retrospectively. Cox regression was performed to determine the risk factors for short-term survival among ACLF patients following LT. Five conventional score systems (the MELD score, ABIC, CLIF-C OFs, CLIF-SOFAs and CLIF-C ACLFs) in forecasting short-term survival were estimated through the receiver operating characteristic (ROC). Four machine-learning (ML) models, including support vector machine (SVM), logistic regression (LR), multi-layer perceptron (MLP) and random forest (RF), were also established for short-term survival prediction. RESULTS: Cox regression analysis demonstrated that creatinine (Cr) and international normalized ratio (INR) were the two independent predictors for short-term survival among ACLF patients following LT. The ROC curves showed that the area under the curve (AUC) ML models was much larger than that of conventional models in predicting short-term survival. Among conventional models the model for end stage liver disease (MELD) score had the highest AUC (0.704), while among ML models the RF model yielded the largest AUC (0.940). CONCLUSION: Compared with the traditional methods, the ML models showed good performance in the prediction of short-term prognosis among ACLF patients following LT and the RF model perform the best. It is promising to optimize organ allocation and promote transplant survival based on the prediction of ML models.

Immunofluorescent-aggregation assay based on anti-Salmonella typhimurium IgG-AuNCs, for rapid detection of Salmonella typhimurium.

Sensitive and rapid detection of pathogenic bacteria plays an important role in avoiding food poisoning. However, the practical application value of conventional assays for detection of foodborne bacteria, are limited by major drawbacks; these include the laboriousness of pure culture preparation, complexity of DNA extraction for polymerase chain reaction, and low sensitivity of enzyme-linked immunosorbent assay. Herein, we designed a non-complex strategy for the sensitive, quantitative, and rapid detection of Salmonella typhimurium with high specificity, using an anti-Salmonella typhimurium IgG-AuNC-based immunofluorescent-aggregation assay. Salmonella typhimurium was agglutinated with fluorescent anti-Salmonella typhimurium IgG-AuNC on a glass slide, and observed using a fluorescence microscope with photoexcitation and photoemission at 560 nm and 620 nm, respectively. Under optimized reaction conditions, the AuNC-based immunofluorescent-aggregation assay had a determination range between 7.0 × 103 and 3.0 × 108 CFU/mL, a limit of detection of 1.0 × 103 CFU/mL and an assay response time of 3 min. The technique delivered good results in assessing real samples.

Proposed Superconducting Electride Li_{6}C by sp-Hybridized Cage States at Moderate Pressures.

The combination of electride state and superconductivity within the same compound, e.g., [Ca_{24}Al_{28}O_{6}]^{4+}(4e^{-}), opens up a new category of conventional superconductors. However, neither the underlying causations to explain superconducting behaviors nor effects of interstitial quasiatoms (ISQs) on superconductivity remain unclear. Here we have designed an efficient and resource-saving method to identify superconducting electrides only by chemical compositions and bonding characteristics. A representative superconducting electride Li_{6}C with a noteworthy T_{c} of 10 K below 1 Mbar among the known binary electrides has been revealed. Our first-principles studies unveil that the anomalous sp-hybridized cage-state ISQs, as a guest in Li_{6}C, exhibit unexpected ionic and covalent bonds, which act as a chemical precompression to lower dynamically stable pressure. More importantly, we uncover that, contrary to common expectations, the high T_{c} is attributed to the strong electron-phonon coupling derived from the synergy of interatomic coupling effect, phonon softening caused by Fermi surface nesting, and phonon-coupled bands, which are mainly dominated by host sp-hybridized electrons, rather than the ISQs. Our present results elucidate a new superconducting mechanism of electrides and shed light on the way for seeking a high-T_{c} superconductor at lower pressures in cage-state electrides.

A Heparinase Sensor Based on a Ternary System of Hg2+-Heparin-Osmium Nanoparticles.

A visual assay for the detection of heparinase was developed on the basis of a ternary system of Hg2+-heparin-osmium nanoparticles (OsNPs). First, heparin-capped OsNPs (heparin-OsNPs) were synthesized by a facile reduction method using heparin as the protecting/stabilizing agent. The oxidase-like activity of heparin-OsNPs, however, turned out to be low, which somewhat limits their application. We discovered that Hg2+ can significantly/specifically boost the oxidase-like activity of heparin-OsNPs via electrostatic interaction. The oxidase-like activity of heparin-OsNPs toward the oxidation of the substrate, 3,3',5,5'-tetramethylbenzidine, by dissolved O2 was found to increase by 76-fold in the presence of Hg2+. More significantly, heparin in heparin-OsNPs could be specifically hydrolyzed into small fragments in the presence of heparinase, which resulted in the weakening of the oxidase-like activity of Hg2+/heparin-OsNPs. On the basis of these findings, a linear response of the sensor for heparinase was obtained in the range 20-1000 µg/L with a low detection limit (15 µg/L), which is comparable to those of other reported sensors. Further, the colorimetric sensor was employed for the detection of heparinase in human serum samples with satisfactory results. We speculate that combining such surface modification of the osmium nanozyme with a sensing element could be an interesting direction for promoting nanozyme research in medical diagnosis.

Ascorbate Oxidase Mimetic Activity of Copper(II) Oxide Nanoparticles.

Although oxidase mimetic nanozymes have been widely investigated, specific biological molecules have rarely been explored as substrates, particularly in the case of ascorbate oxidase (AAO) mimetic nanozymes. Herein, we demonstrate for the first time that copper(II) oxide nanoparticles (CuO NPs) catalyze the oxidation of ascorbic acid (AA) by dissolved O2 (as a green oxidant) to form dehydroascorbic acid (DHAA), thus functioning as a new kind of AAO mimic. Under neutral conditions, the Michaelis-Menten constant of CuO NPs (0.1302 mm) is similar to that of AAO (0.0840 mm). Furthermore, the robustness of CuO NPs is greater than that of AAO, thus making them suitable for applications under various conditions. As a demonstration, a fluorescence AA sensor based on the AAO mimetic activity of CuO NPs was developed. To obtain a fluorescent product, o-phenylenediamine (OPDA) was used to react with the DHAA produced by the oxidation of AA catalyzed by CuO NPs. The developed sensor was cost-effective and easy to fabricate and exhibited high selectivity/sensitivity with a wide linear range (1.25×10-6 to 1.125×10-4 m) and a low detection limit (3.2×10-8 m). The results are expected to aid in expanding the applicability of oxidase mimetic nanozymes in a variety of fields such as biology, medicine, and detection science.

The study of the association between immune monitoring and pneumonia in kidney transplant recipients through machine learning models.

BACKGROUND: Kidney transplantation is the optimal treatment to cure the patients with end-stage renal disease (ESRD). However, the infectious complication, especially pneumonia, is the main cause of mortality in the early stage. Immune monitoring by relevant biomarkers provides direct evidence of immune status. We aimed to study the association between immune monitoring and pneumonia in kidney transplant patients through machine learning models. METHODS: A total of 146 patients receiving the immune monitoring panel in our center, including 46 pneumonia recipients and 100 stable recipients, were retrospectively reviewed to develop the models. All the models were validated by external data containing 10 pneumonia recipients and 32 stable recipients. The immune monitoring panel consisted of the percentages and absolute cell counts of CD3+CD4+ T cells, CD3+CD8+ T cells, CD19+ B cells and natural killer (NK) cells, and median fluorescence intensity (MFI) of human leukocyte antigen (HLA)-DR on monocytes and CD64 on neutrophils. The machine learning models including support vector machine (SVM), logistic regression (LR), multi-layer perceptron (MLP) and random forest (RF) were applied for analysis. RESULTS: The pneumonia and stable groups showed significant difference in cell counts of each subpopulation and MFI of monocyte HLA-DR and neutrophil CD64. The SVM model by monocyte HLA-DR (MFI), neutrophil CD64 (MFI), CD8+ T cells (cells/µl), NK cells (cell/µl) and TBNK (T cells, B cells and NK cells, cells/µl) had the best performance with the average area under the curve (AUC) of 0.940. The RF model best predicted the patients who would progress into severe pneumonia, with the average AUC of 0.760. All the models had good performance validated by external data. CONCLUSIONS: The immune monitoring panel was tightly associated with pneumonia in kidney transplant recipients. The models developed by machine learning techniques identified patients at risk and predicted the prognosis. Based on the results of immune monitoring, better individualized therapy might be achieved.

Psychological Impact and Coping Strategies of Frontline Medical Staff in Hunan Between January and March 2020 During the Outbreak of Coronavirus Disease 2019 (COVID­19) in Hubei, China.

BACKGROUND Throughout China, during the recent epidemic in Hubei province, frontline medical staff have been responsible for tracing contacts of patients infected with coronavirus disease 2019 (COVID­19). This study aimed to investigate the psychological impact and coping strategies of frontline medical staff in Hunan province, adjacent to Hubei province, during the COVID­19 outbreak between January and March 2020. MATERIAL AND METHODS A cross-sectional observational study included doctors, nurses, and other hospital staff throughout Hunan province between January and March 2020. The study questionnaire included five sections and 67 questions (scores, 0-3). The chi-squared χ² test was used to compare the responses between professional groups, age-groups, and gender. RESULTS Study questionnaires were completed by 534 frontline medical staff. The responses showed that they believed they had a social and professional obligation to continue working long hours. Medical staff were anxious regarding their safety and the safety of their families and reported psychological effects from reports of mortality from COVID­19 infection. The availability of strict infection control guidelines, specialized equipment, recognition of their efforts by hospital management and the government, and reduction in reported cases of COVID­19 provided psychological benefit. CONCLUSIONS The COVID­19 outbreak in Hubei resulted in increased stress for medical staff in adjacent Hunan province. Continued acknowledgment of the medical staff by hospital management and the government, provision of infection control guidelines, specialized equipment and facilities for the management of COVID­19 infection should be recognized as factors that may encourage medical staff to work during future epidemics.

Anti-Diabetogenic Properties of Mineralocorticoid Receptor Antagonists: Implications for Enhanced Safety and Efficacy of Post-Transplantation Pharmacotherapies.

Widespread usage of the calcineurin inhibitors tacrolimus and cyclosporine A as post-transplantation immunosuppressive agents is fraught with severe nephrotoxic and diabetogenic side effects. More recently, tapering of calcineurin inhibitor-based immunotherapies with concurrent administration of the mammalian target of rapamycin (mTOR) inhibitors sirolimus and everolimus has been employed within pharmacological regimens designed to achieve better safety and efficacy for preservation of allograft kidney function. Collected preclinical data and recent clinical study, however, indicate that usage of calcineurin inhibitors and/or mTOR blockers as immunosuppressive agents promotes equivalent diabetogenic side effects. Based on a wealth of validating preclinical studies, we contend that the favorable metabolic effects of mineralocorticoid receptor antagonists, such as spironolactone, support their inclusion in novel immunosuppressive strategies to inhibit new onset type II diabetic symptoms in post-transplantation patient populations.

Comparison of Physical Crossmatch and Virtual Crossmatch to Identify Preexisting Donor-Specific Human Leukocyte Antigen (HLA) Antibodies and Outcome Following Kidney Transplantation.

BACKGROUND Physical crossmatch (PXM) and virtual crossmatch (VXM) are applied to identify preexisting donor-specific human leukocyte antigen (HLA) antibodies in patients awaiting kidney transplantation. Recently, high-resolution epitope analysis has emerged as a novel strategy for VXM. A retrospective clinical study compared PXM with VXM before kidney transplantation and recipient outcome following transplantation. MATERIAL AND METHODS Between August 2017 and March 2018, 239 patients underwent crossmatching and 94 patients received a donor kidney. A complement-dependent cytotoxicity (CDC) PXM assay and VXM using serological and epitope analysis identified donor-specific antibodies (DSA). Crossmatch results and clinical outcome at 3 months were compared. RESULTS VXM identified serological DSA (sDSA), verified epitope DSA, and total epitope DSA in 74 (31.0%), 39 (16.3%), and 49 (20.5%) cases, respectively. Eleven cases (4.6%) had a positive PXM detected by the CDC assay. Of 94 kidney transplant recipients, 21 had preexisting sDSA but were negative in PXM; there was 1 case of delayed graft function (DGF) and no cases of hyperacute rejection or acute rejection. Of the rest of the 73 recipients who were negative for sDSA, 8 had acute rejection (P=0.253) and 19 had DGF (P=0.037). No significant differences were found in graft survival at 3 months. CONCLUSIONS High-resolution epitope analysis identified fewer cases with DSA compared with serological analysis. Because patients with and without sDSA had a similar short-term outcome in the setting of a negative PXM, the presence of preexisting sDSA, determined by VXM, should not be an absolute contraindication for kidney transplantation.

Association Between Red Blood Cell Distribution Width and Prognosis of Renal Transplant Recipients with Early-Onset Pneumonia.

BACKGROUND Following renal transplantation, early-onset pneumonia is a frequent and severe infection-related complication. Red blood cell distribution width (RDW) has been reported as a predictive marker among patients with infectious diseases. Therefore, the aim of this study was to explore the significance of RDW in predicting prognosis, including 60-day mortality, in renal transplant recipients with early-onset pneumonia. MATERIAL AND METHODS Clinical data from patients who developed early-onset pneumonia after renal transplantation were retrospectively reviewed. Patients were divided into 2 groups: those with an RDW ≤15.0% and those with an RDW >15.0%. The 60-day mortality, bacteremia, need for mechanical ventilation, renal transplant rejection rate, and number of admissions to the intensive care unit (ICU) were estimated by Kaplan-Meier methods. Univariate and multivariate Cox regression analyses were performed to determine the risk factors for 60-day mortality. RESULTS Among the 118 patients participating in the study, 18 (15.2%) died during the 60-day follow-up. Kaplan-Meier analysis showed a death rate of 9.38% in the group with an RDW ≤15.0%, and a death rate of 40.9% in the group with an RDW >15.0% (P<0.001). Patient prognosis, including episodes of mechanical ventilation, graft rejection, and ICU admissions were significantly different between groups (P<0.01). RDW was an independent factor related to higher 60-day mortality (HR, 1.672; 95% CI, 1.111-2.516). CONCLUSIONS Among patients with early-onset pneumonia following renal transplantation, increased RDW >15.0% was significantly associated with prognosis and 60-day mortality.