The emerging roles of microbiota-derived extracellular vesicles in psychiatric disorders.

Major depressive disorder, schizophrenia, and bipolar disorder are three major psychiatric disorders that significantly impact the well-being and overall health of patients. Some researches indicate that abnormalities in the gut microbiota can trigger certain psychiatric diseases. Microbiota-derived extracellular vesicles have the ability to transfer bioactive compounds into host cells, altering signaling and biological processes, ultimately influencing the mental health and illness of the host. This review aims to investigate the emerging roles of microbiota-derived extracellular vesicles in these three major psychiatric disorders and discusses their roles as diagnostic biomarkers and therapies for these psychiatric disorders.

Distinct fibroblast subpopulations associated with bone, brain or intrapulmonary metastasis in advanced non-small-cell lung cancer.

BACKGROUND: Bone or brain metastases may develop in 20-40% of individuals with late-stage non-small-cell lung cancer (NSCLC), resulting in a median overall survival of only 4-6 months. However, the primary lung cancer tissue's distinctions between bone, brain and intrapulmonary metastases of NSCLC at the single-cell level have not been underexplored. METHODS: We conducted a comprehensive analysis of 14 tissue biopsy samples obtained from treatment-naïve advanced NSCLC patients with bone (n = 4), brain (n = 6) or intrapulmonary (n = 4) metastasis using single-cell sequencing originating from the lungs. Following quality control and the removal of doublets, a total of 80 084 cells were successfully captured. RESULTS: The most significant inter-group differences were observed in the fraction and function of fibroblasts. We identified three distinct cancer-associated fibroblast (CAF) subpopulations: myofibroblastic CAF (myCAF), inflammatory CAF (iCAF) and antigen-presenting CAF (apCAF). Notably, apCAF was prevalent in NSCLC with bone metastasis, while iCAF dominated in NSCLC with brain metastasis. Intercellular signalling network analysis revealed that apCAF may play a role in bone metastasis by activating signalling pathways associated with cancer stemness, such as SPP1-CD44 and SPP1-PTGER4. Conversely, iCAF was found to promote brain metastasis by activating invasion and metastasis-related molecules, such as MET hepatocyte growth factor. Furthermore, the interaction between CAFs and tumour cells influenced T-cell exhaustion and signalling pathways within the tumour microenvironment. CONCLUSIONS: This study unveils the direct interplay between tumour cells and CAFs in NSCLC with bone or brain metastasis and identifies potential therapeutic targets for inhibiting metastasis by disrupting these critical cell-cell interactions.

[Correlation between diaphragmatic-rapid shallow breathing index and lung ultrasound score in elderly patients with mechanical ventilation and its predictive value for weaning results].

OBJECTIVE: To investigate the correlation between diaphragmatic-rapid shallow breathing index (D-RSBI) and lung ultrasound score (LUS) in elderly patients with mechanical ventilation and its predictive value for weaning results. METHODS: A retrospective study was conducted. The clinical data of elderly patients (age > 60 years old) with invasive positive pressure ventilation (IPPV) admitted to the department of intensive care unit (ICU) of the First Affiliated Hospital of Jinzhou Medical University from January 2021 to June 2022 were enrolled. According to the outcome of withdrawal, the patients were divided into successful and failed groups. The differences in gender, age, acute physiology and chronic health evaluation II (APACHE II), D-RSBI and LUS before weaning and extubation were compared between the two groups. Pearson correlation was used to analyze the correlation between D-RSBI and LUS. The predictive value of D-RSBI and LUS on weaning results of elderly patients with IPPV was analyzed by receiver operator characteristic curve (ROC curve). RESULTS: A total of 398 elderly patients with IPPV were enrolled, including 300 successful weaning patients and 98 failed weaning patients. There were no significant differences in gender and age between the failed group and successful group [male: 55.1% (54/98) vs. 59.0% (177/300), age (years old): 67.02±5.03 vs. 66.96±4.99, both P > 0.05]. APACHE II score in the failed group was significantly higher than that in the successful group (17.09±3.30 vs. 16.06±3.81, P < 0.05), and the D-RSBI and LUS score before extubation were significantly higher than those in the successful group [D-RSBI (time×min-1×mm-1): 2.19±0.33 vs. 1.60±0.22, LUS: 17.30±3.04 vs. 11.97±3.20, both P < 0.01]. All patients showed a significant positive correlation between D-RSBI and LUS score (r = 0.406, P = 0.000). ROC curve analysis showed that the area under the curve (AUC) of D-RSBI for predicting weaning outcomes in elderly IPPV patients was 0.920, with a 95% confidence interval (95%CI) of 0.881-0.958 and P = 0.000. When the cut-off value was 1.85 times×min-1×mm-1, the sensitivity was 88.7% and the specificity was 86.7%. The AUC of LUS score for predicting weaning outcome in elderly IPPV patients was 0.875, with a 95%CI of 0.839-0.912 and P = 0.000. When the cut-off value was 14.50, the sensitivity was 75.7% and the specificity was 84.7%. CONCLUSIONS: There is a significant correlation between D-RSBI and LUS score in elderly mechanically ventilated patients, both of them can predict weaning outcome in elderly patients with mechanical ventilation.

eccDNA-pipe: an integrated pipeline for identification, analysis and visualization of extrachromosomal circular DNA from high-throughput sequencing data.

Extrachromosomal circular DNA (eccDNA) is currently attracting considerable attention from researchers due to its significant impact on tumor biogenesis. High-throughput sequencing (HTS) methods for eccDNA identification are continually evolving. However, an efficient pipeline for the integrative and comprehensive analysis of eccDNA obtained from HTS data is still lacking. Here, we introduce eccDNA-pipe, an accessible software package that offers a user-friendly pipeline for conducting eccDNA analysis starting from raw sequencing data. This dataset includes data from various sequencing techniques such as whole-genome sequencing (WGS), Circle-seq and Circulome-seq, obtained through short-read sequencing or long-read sequencing. eccDNA-pipe presents a comprehensive solution for both upstream and downstream analysis, encompassing quality control and eccDNA identification in upstream analysis and downstream tasks such as eccDNA length distribution analysis, differential analysis of genes enriched with eccDNA and visualization of eccDNA structures. Notably, eccDNA-pipe automatically generates high-quality publication-ready plots. In summary, eccDNA-pipe provides a comprehensive and user-friendly pipeline for customized analysis of eccDNA research.

Astrocyte-derived lactoferrin reduces ß-amyloid burden by promoting the interaction between p38 kinase and PP2A phosphatase in male APP/PS1 transgenic mice.

BACKGROUND AND PURPOSE: Overexpression of astrocytic lactoferrin (Lf) was observed in the brain of Alzheimer's disease (AD) patients, whereas the role of astrocytic Lf in AD progression remains unexplored. In this study, we aimed to evaluate the effects of astrocytic Lf on AD progression. EXPERIMENTAL APPROACH: Male APP/PS1 mice with astrocytes overexpressing human Lf were developed to evaluate the effects of astrocytic Lf on AD progression. N2a-sw cells also were employed to further uncover the mechanism of astrocytic Lf on ß-amyloid (Aß) production. KEY RESULTS: Astrocytic Lf overexpression increased protein phosphatase 2A (PP2A) activity and reduced amyloid precursor protein (APP) phosphorylation, Aß burden and tau hyperphosphorylation in APP/PS1 mice. Mechanistically, astrocytic Lf overexpression promoted the uptake of astrocytic Lf into neurons in APP/PS1 mice, and conditional medium from astrocytes overexpressing Lf inhibited p-APP (Thr668) expression in N2a-sw cells. Furthermore, recombinant human Lf (hLf) significantly enhanced PP2A activity and inhibited p-APP expression, whereas inhibition of p38 or PP2A activities abrogated the hLf-induced p-APP down-regulation in N2a-sw cells. Additionally, hLf promoted the interaction of p38 and PP2A via p38 activation, thereby enhancing PP2A activity, and low-density lipoprotein receptor-related protein 1 (LRP1) knockdown significantly reversed the hLf-induced p38 activation and p-APP down-regulation. CONCLUSIONS AND IMPLICATIONS: Our data suggested that astrocytic Lf promoted neuronal p38 activation, via targeting to LRP1, subsequently promoting p38 binding to PP2A to enhance PP2A enzyme activity, which finally inhibited Aß production via APP dephosphorylation. In conclusion, promoting astrocytic Lf expression may be a potential strategy against AD. LINKED ARTICLES: This article is part of a themed issue From Alzheimer's Disease to Vascular Dementia: Different Roads Leading to Cognitive Decline. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.6/issuetoc.

Single-cell transcriptome profiling reveals immune and stromal cell heterogeneity in primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a complex autoimmune disease characterized by lymphocytic infiltration and exocrine dysfunction, particularly affecting the salivary gland (SG). We employed single-cell RNA sequencing to investigate cellular heterogeneity in 11 patients with pSS and 5 non-SS controls. Notably, patients with pSS exhibited downregulated SOX9 in myoepithelial cells, potentially associated with impaired epithelial regeneration. An expanded ACKR1+ endothelial subpopulation in patients with pSS suggested a role in facilitating lymphocyte transendothelial migration. Our analysis of immune cells revealed expanded IGHD+ naive B cells in peripheral blood from patients with pSS. Pseudotime trajectory analysis outlined a bifurcated differentiation pathway for peripheral B cells, enriching three subtypes (VPREB3+ B, BANK1+ B, CD83+ B cells) within SGs in patients with pSS. Fibroblasts emerged as pivotal components in a stromal-immune interaction network, potentially driving extracellular matrix disruption, epithelial regeneration impairment, and inflammation. Our study illuminates immune and stromal cell heterogeneity in patients with pSS, offering insights into therapeutic strategies.

Construction of 3D bioprinting of HAP/collagen scaffold in gelation bath for bone tissue engineering.

Reconstruction of bone defects remains a clinical challenge, and 3D bioprinting is a fabrication technology to treat it via tissue engineering. Collagen is currently the most popular cell scaffold for tissue engineering; however, a shortage of printability and low mechanical strength limited its application via 3D bioprinting. In the study, aiding with a gelatin support bath, a collagen-based scaffold was fabricated via 3D printing, where hydroxyapatite (HAP) and bone marrow mesenchymal stem cells (BMSCs) were added to mimic the composition of bone. The results showed that the blend of HAP and collagen showed suitable rheological performance for 3D extrusion printing and enhanced the composite scaffold's strength. The gelatin support bath could effectively support the HAP/collagen scaffold's dimension with designed patterns at room temperature. BMSCs in/on the scaffold kept living and proliferating, and there was a high alkaline phosphate expression. The printed collagen-based scaffold with biocompatibility, mechanical properties and bioactivity provides a new way for bone tissue engineering via 3D bioprinting.

A single-cell landscape of pre- and post-menopausal high-grade serous ovarian cancer ascites.

High-grade serous ovarian cancer (HGSOC) is a hormone-related cancer with high mortality and poor prognosis. Based on the transcriptome of 57,444 cells in ascites from 10 patients with HGSOC (including 5 pre-menopausal and 5 post-menopausal patients), we identified 14 cell clusters which were further classified into 6 cell types, including T cells, B cells, NK cells, myeloid cells, epithelial cells, and stromal cells. We discovered an increased proportion of epithelial cells and a decreased proportion of T cells in pre-menopausal ascites compared with post-menopausal ascites. GO analysis revealed the pre-menopausal tumor microenvironments (TME) are closely associated with viral infection, while the post-menopausal TME are mostly related to the IL-17 immune pathway. SPP1/CD44-mediated crosstalk between myeloid cells and B cells, NK cells, and stromal cells mainly present in the pre-menopausal group, while SPP1/PTGER4 -mediated crosstalk between myeloid cells and epithelial cells mostly present in the post-menopausal group.

Effects of additives on the performance of a laser-induced graphene sensor modified with ZrO2 nanoparticles for OP detection.

In this study, a simple and portable electrochemical sensor based on laser-induced graphene (LIG) has been developed to systematically investigate the feasibility of LIG as an electrode to detect organophosphorus pesticides (OPs). It proves that the LIG-based electrode has a relatively high electrochemically active surface area (ECSA) and heterogeneous electron transfer (HET) of 0.100 cm2 and 0.000825 cm s-1, respectively. In addition, zirconium dioxide nanoparticles (ZrO2 NPs) have been modified on the electrode with three different binders, ß-cyclodextrin (ß-CD), chitosan (CS) and Nafion, to improve the adsorption capacity of the electrode toward OPs, and the effect of the binders on the performance of the as-fabricated sensor has been investigated in detail. The results show that ß-CD increases not only the electrochemically active surface area of the electrode but also the redox peak current of methyl parathion (MP). To evaluate the sensitivity of the sensor, differential pulse voltammetry (DPV) curves have been tested in solutions containing different concentrations of MP using ZrO2-ß-CD/LIG as an electrode, which shows a detection range of 5-200 ng ml-1 and a detection limit of 0.89 ng ml-1. In summary, the LIG-based sensor has a low detection limit, high sensitivity and good interference resistance, and thus has tremendous potential for the detection of pesticides in the environment.

The human islet amyloid polypeptide reduces hippocampal tauopathy and behavioral impairments in P301S mice without inducing neurotoxicity or seeding amyloid aggregation.

Recent evidence suggests that human islet amyloid polypeptide (h-IAPP) accumulates in the brains of Alzheimer's disease (AD) patients and may interact with Aß or microtubule associated protein tau to associate with the neurodegenerative process. Increasing evidence indicates a potential protective effect of h-IAPP against Aß-induced neurotoxicity in AD mouse models. However, a direct therapeutic effect of h-IAPP supplementation on tauopathy has not been established. Here, we found that long-term h-IAPP treatment attenuated tau hyperphosphorylation levels and induced neuroinflammation and oxidative damage, prevented synaptic loss and neuronal degeneration in the hippocampus, and alleviated behavioral deficits in P301S transgenic mice (a mouse model of tauopathy). Restoration of insulin sensitization, glucose/energy metabolism, and activated BDNF signaling also contributed to the underlying mechanisms. These findings suggest that seemly h-IAPP has promise for the treatment of neurodegenerative disorders with tauopathy, such as AD.

Dynamics and regulation of mitotic chromatin accessibility bookmarking at single-cell resolution.

Although mitotic chromosomes are highly compacted and transcriptionally inert, some active chromatin features are retained during mitosis to ensure the proper postmitotic reestablishment of maternal transcriptional programs, a phenomenon termed "mitotic bookmarking." However, the dynamics and regulation of mitotic bookmarking have not been systemically surveyed. Using single-cell transposase-accessible chromatin sequencing (scATAC-seq), we examined 6538 mitotic L02 human liver cells of variable stages and found that chromatin accessibility remained changing throughout cell division, with a constant decrease until metaphase and a gradual increase as chromosomes segregated. In particular, a subset of chromatin regions were identified to remain open throughout mitosis, and genes associated with these bookmarked regions are primarily linked to rapid reactivation upon mitotic exit. We also demonstrated that nuclear transcription factor Y subunit α (NF-YA) preferentially occupied bookmarked regions and contributed to transcriptional reactivation after mitosis. Our study uncovers the dynamic and regulatory blueprint of mitotic bookmarking.

Single-cell transcriptome profiling and chromatin accessibility reveal an exhausted regulatory CD4+ T cell subset in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, and CD4+ T cells are known to promote SLE development. Here, we explore heterogeneities in the CD4+ T cell regulome and their associations with SLE pathogenesis by performing assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and single-cell transcriptome sequencing (single-cell RNA sequencing [scRNA-seq]) of peripheral CD4+ T cells from 72 SLE patients and 30 healthy controls. Chromatin accessibility signatures of CD4+ T cells are correlated with disease severity. Further, we generate 34,176 single-cell transcriptomes of healthy and SLE CD4+ T cells and reveal transcriptional dysfunction of regulatory T (Treg) cells, identifying two Treg subpopulations, among which the CCR7lowCD74hi Treg subgroup features type I interferon-induced functional exhaustion in SLE patients. These transcriptome-level findings for SLE Tregs are mirrored in trends from the ATAC-seq data. Our study establishes a rich empirical foundation for understanding SLE and uncovers previously unknown contributions of Treg with exhaustion-like properties to SLE pathogenesis.

Single-Cell Heterogeneity of the Liver-Infiltrating Lymphocytes in Individuals with Chronic Echinococcus multilocularis Infection.

Human alveolar echinococcosis (AE) is a tumor-like disease predominantly located in the liver. The cellular composition and heterogeneity of the lesion-infiltrating lymphocytes which produce an "immunosuppressive" microenvironment are poorly understood. Here, we profiled 83,921 CD45+ lymphocytes isolated from the peripheral blood (PB), perilesion (PL), and adjacent normal (AN) liver tissue of four advanced-stage AE patients using single-cell RNA and T-cell receptor (TCR) sequencing technology. We identified 23 large clusters, and the distributions and transcriptomes of these cell clusters in the liver and periphery were different. The cellular proportions of exhausted CD8+ T cells and group 2 innate lymphoid cells (ILC2s) were notably higher in PL tissue, and the expression features of these cell subsets were related to neoplasm metastasis and immune response suppression. In the 5 CD8+ T-cell populations, only CD8+ mucosa-associated invariant T (MAIT) cells were enriched in PL samples and the TRAV1-2_TRAJ33_TRAC TCR was clonally expanded. In the 11 subsets of CD4+ T cells, Th17 cells and induced regulatory T cells (iTregs) were preferentially enriched in PL samples, and their highly expressed genes were related to cell invasion, tumor metastasis, and inhibition of the inflammatory immune response. Exhaustion-specific genes (TIGIT, PD-1, and CTLA4) were upregulated in Tregs. Interestingly, there was a close contact between CD8+ T cells and iTregs or Th17 cells, especially for genes related to immunosuppression, such as PDCD1-FAM3C, which were highly expressed in PL tissue. This transcriptional data set provides valuable insights and a rich resource for deeply understanding the immune microenvironment in AE, which could provide potential target signatures for AE diagnosis and immunotherapies.

Astrocyte-specific loss of lactoferrin influences neuronal structure and function by interfering with cholesterol synthesis.

Growing evidence indicates that circulating lactoferrin (Lf) is implicated in peripheral cholesterol metabolism disorders. It has emerged that the distribution of Lf changes in astrocytes of aging brains and those exhibiting neurodegeneration; however, its physiological and/or pathological role remains unknown. Here, we demonstrate that astrocyte-specific knockout of Lf (designated cKO) led to decreased body weight and cognitive abnormalities during early life in mice. Accordingly, there was a reduction in neuronal outgrowth and synaptic structure in cKO mice. Importantly, Lf deficiency in the primary astrocytes led to decreased sterol regulatory element binding protein 2 (Srebp2) activation and cholesterol production, and cholesterol content in cKO mice and/or in astrocytes was restored by exogenous Lf or a Srebp2 agonist. Moreover, neuronal dendritic complexity and total dendritic length were decreased after culture with the culture medium of the primary astrocytes derived from cKO mice and that this decrease was reversed after cholesterol supplementation. Alternatively, these alterations were associated with an activation of AMP-activated protein kinase (AMPK) and inhibition of SREBP2 nuclear translocation. These data suggest that astrocytic Lf might directly or indirectly control in situ cholesterol synthesis, which may be implicated in neurodevelopment and several neurological diseases.

Novel melatonin-trientine conjugate as potential therapeutic agents for Alzheimer's disease.

Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the ß-amyloid (Aß) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aß deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aß levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology.

ATP13A2 Declines Zinc-Induced Accumulation of α-Synuclein in a Parkinson's Disease Model.

Parkinson's disease (PD) is characterized by the presence of Lewy bodies caused by α-synuclein. The imbalance of zinc homeostasis is a major cause of PD, promoting α-synuclein accumulation. ATP13A2, a transporter found in acidic vesicles, plays an important role in Zn2+ homeostasis and is highly expressed in Lewy bodies in PD-surviving neurons. ATP13A2 is involved in the transport of zinc ions in lysosomes and exosomes and inhibits the aggregation of α-synuclein. However, the potential mechanism underlying the regulation of zinc homeostasis and α-synuclein accumulation by ATP13A2 remains unexplored. We used α-synuclein-GFP transgenic mice and HEK293 α-synuclein-DsRed cell line as models. The spatial exploration behavior of mice was significantly reduced, and phosphorylation levels of α-synuclein increased upon high Zn2+ treatment. High Zn2+ also inhibited the autophagy pathway by reducing LAMP2a levels and changing the expression of LC3 and P62, by reducing mitochondrial membrane potential and increasing the expression of cytochrom C, and by activating the ERK/P38 apoptosis signaling pathway, ultimately leading to increased caspase 3 levels. These protein changes were reversed after ATP13A2 overexpression, whereas ATP13A2 knockout exacerbated α-synuclein phosphorylation levels. These results suggest that ATP13A2 may have a protective effect on Zn2+-induced abnormal aggregation of α-synuclein, lysosomal dysfunction, and apoptosis.

Tissue engineered bone via templated hBMSCs mineralization and its application for bone repairing.

To develop bone implants, a novel tissue-engineered bone was constructed via templated human bone mesenchymal stem cells (hBMSCs) mineralization. Firstly, an osteoid-like template (Os-template) with aligned collagen fibers was prepared and followed by seeding hBMSCs to mimic the process of bone formation. After being cultured over weeks, the cells produced collagen fibers in an orderly aligned osteomorphic fashion. Further, a novel tissue-engineered bone with mineralized collagen fiber (mOs-ECM) was subsequently achieved after cell mineralization, showing a high degree of osteomimicry in terms of both composition and structure. When applied to the rat cranial bone defect model, the mOs-ECM significantly promoted the new bone formation and fused with the host bone. The study indicated that microscopic cell mineralization could be guided by artificially designed templates and successfully fabricated a macroscopic implant with a pronounced effect on bone repairing.

A transcriptome atlas and interactive analysis platform for autoimmune disease.

With the rapid development of next-generation sequencing technology, many laboratories have produced a large amount of single-cell transcriptome data of blood and tissue samples from patients with autoimmune diseases, which enables in-depth studies of the relationship between gene transcription and autoimmune diseases. However, there is still a lack of a database that integrates the large amount of autoimmune disease transcriptome sequencing data and conducts effective analysis. In this study, we developed a user-friendly web database tool, Interactive Analysis and Atlas for Autoimmune disease (IAAA), which integrates bulk RNA-seq data of 929 samples of 10 autoimmune diseases and single-cell RNA-seq data of 783 203 cells in 96 samples of 6 autoimmune diseases. IAAA also provides customizable analysis modules, including gene expression, difference, correlation, similar gene detection and cell-cell interaction, and can display results in three formats (plot, table and pdf) through custom parameters. IAAA provides valuable data resources for researchers studying autoimmune diseases and helps users deeply explore the potential value of the current transcriptome data. IAAA is available. Database URL: http://galaxy.ustc.edu.cn/IAAA.

[Correlation between dead space fraction and pulmonary ultrasound score in patients with acute respiratory distress syndrome and its prognostic value].

OBJECTIVE: To investigate the correlation between dead space fraction and lung ultrasound score (LUS) and their prognostic value in patients with acute respiratory distress syndrome (ARDS). METHODS: The data of 98 patients with ARDS treated in the intensive care unit (ICU) of the First Affiliated Hospital of Jinzhou Medical University from January to December 2020 were collected and analyzed. The gender, age, acute physiology and chronic health evaluation II (APACHE II), oxygenation index, dead space fraction and LUS score immediately and 24, 48, 72 and 96 hours after ICU admission and 28-day outcomes of all patients were collected. Pearson correlation was used to analyze the correlation between dead space fraction and LUS score. Binary Logistic regression was performed to analyze whether the dead space fraction and LUS score could be the risk factors of the prognosis in patients with ARDS. Receiver operator characteristic curve (ROC) was used to analyze the predictive effect of dead space fraction and LUS score on 28-day mortality in patients with ARDS. RESULTS: A total of 98 patients with ARDS were included, of which 76 cases survived and 22 cases died within 28 days. With the prolongation of ICU stay, the dead space fraction and LUS score in the survival group increased first and then decreased. The dead space fraction and LUS score in the death group continued to increase to 96 hours, and were significantly higher than those in the survival group (dead space fraction: 0.569±0.019 vs. 0.491±0.021, LUS score: 20.09±2.39 vs. 15.13±1.91, both P < 0.05). There was a positive correlation between the dead space fraction and LUS score at 48, 72 and 96 hours in ICU (r values were 0.200, 0.471 and 0.677, all P < 0.05). Binary Logistic regression analysis showed that dead space fraction and LUS score were independent risk factors affecting the prognosis of patients with ARDS [dead space fraction: odds ratio (OR) was 69.064, 95% confidence interval (95%CI) was 22.680-123.499, P = 0.008; LUS score: OR was 4.790, 95%CI was 1.609-14.261, P = 0.005]. The results of ROC curve analysis showed that the dead space fraction at 48, 72 and 96 hours after ICU admission could be used to predict the 28-day mortality of patients with ARDS, the sensitivity was 59.1%, 90.9% and 95.5%, and the specificity was 89.5%, 80.3% and 98.7%. The area under the curve (AUC) of dead space fraction predicting 28-day mortality was 0.802, 0.952 and 0.998, all P < 0.01. The LUS score of 72 hours and 96 hours in ICU could be used to predict the 28-day mortality of patients with ARDS, the sensitivity was 77.3%, 77.3% and 100.0%, and the specificity was 68.4%, 88.2% and 80.3%, respectively. The AUC of the LUS score to predict the 28-day mortality of patients were 0.935 and 0.959, both P < 0.01. CONCLUSIONS: There was significant correlation between dead space fraction and LUS score, both of which were risk factors of 28-day mortality and be used to evaluate the 28-day prognosis of patients with ARDS.

Single-cell transcriptomics reveal a unique memory-like NK cell subset that accumulates with ageing and correlates with disease severity in COVID-19.

BACKGROUND: Natural killer (NK) cells are innate lymphoid cells that mediate antitumour and antiviral responses. However, very little is known about how ageing influences human NK cells, especially at the single-cell level. METHODS: We applied single-cell sequencing (scRNA-seq) to human lymphocytes and NK cells from 4 young and 4 elderly individuals and then analysed the transcriptome data using Seurat. We detected the proportion and phenotype of NK cell subsets in peripheral blood samples from a total of 62 young and 52 elderly healthy donors by flow cytometry. We also used flow cytometry to examine the effector functions of NK cell subsets upon IFN-α/IL-12+IL-15/K562/IL-2 stimulation in vitro in peripheral blood samples from a total of 64 young and 63 elderly healthy donors. We finally studied and integrated single-cell transcriptomes of NK cells from 15 young and 41 elderly COVID-19 patients with those from 12 young and 6 elderly healthy control individuals to investigate the impacts of ageing on NK cell subsets in COVID-19 disease. RESULTS: We discovered a memory-like NK subpopulation (NK2) exhibiting the largest distribution change between elderly and young individuals among lymphocytes. Notably, we discovered a unique NK subset that was predominantly CD52+ NK2 cells (NK2.1). These memory-like NK2.1 cells accumulated with age, exhibited proinflammatory characteristics, and displayed a type I interferon response state. Integrative analyses of a large-cohort COVID-19 dataset and our datasets revealed that NK2.1 cells from elderly COVID-19 patients are enriched for type I interferon signalling, which is positively correlated with disease severity in COVID-19. CONCLUSIONS: We identified a unique memory-like NK cell subset that accumulates with ageing and correlates with disease severity in COVID-19. Our results identify memory-like NK2.1 cells as a potential target for developing immunotherapies for infectious diseases and for addressing age-related dysfunctions of the immune system.