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Objective:To screen plasma exosomal protein molecular markers in patients with spinal cord injury (SCI) by applying Label-Free quantification and bioinformatics analysis.Methods:Fifty plasma specimens from the First Affiliated Hospital of Nanjing Medical University (from January 2021 to June 2022) were collected from SCI patients and healthy people, respectively. Plasma exosomes were isolated using ultracentrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis and western blot. Plasma exosomal differentially expressed proteins (DEPs) were analyzed using Label-Free quantitative proteomics, and DEPs were characterized, annotated, and enriched based on Gene Ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) databases. The screened DEPs were validated by western blot and enzyme linked immunosorbent assay (ELISA) using plasma exosomal specimens.Results:According to the spinal cord injury classification of the American Spinal Injury Association, 14 cases were grade A, 19 cases were grade B, 12 cases were grade C, and 5 cases were grade D. Plasma exosomes of SCI patients and control groups showed typical cup-like morphology, with diameters mainly ranging from 30-200 nm. A total of 493 exosomal proteins were identified by Label-Free quantification, and 126 proteins were screened for differential expression, of which 38 were up-regulated and 88 were down-regulated. GO annotation revealed that DEPs were mainly involved in functions such as protein activation cascade, complement activation and immune response. KEGG pathway analysis revealed that DEPs were involved in biological pathways such as complement and coagulation cascade reactions, proteasome and neurodegenerative disease pathways. Two candidate proteins, APOB and S100A9, were initially screened based on quantitative results from proteomics and bioinformatics analyses. Western blot results showed that the relative expression of S100A9 protein in plasma exosomes of 30 SCI patients (1.62±0.19) was elevated compared with that of 30 control groups (0.86±0.24), and the difference was statistically significant ( t=8.55, P<0.001), while the relative expression of APOB protein (1.06±0.13 and 1.02±0.23) were not statistically significant ( t=0.46, P=0.653). The results of ELISA analysis showed that the expression of S100A9 in plasma exosomes of patients with different degrees of SCI (grade A 197.7±11.7 pg/ml, grade B 151.7±15.2 pg/ml, grade C 136.3±14.7 pg/ml) had statistical significance ( F=69.94, P<0.001), the higher the severity of SCI, the higher the expression of S100A9 in plasma exosomes (A vs. B, q=13.11, P<0.001; A vs. C, q=15.66, P<0.001; B vs. C, q=4.19, P=0.005). Conclusion:S100A9 is a potentially valid plasma exosomal molecular marker for assessing the severity of SCI.
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Objective@#To analyze the alterations and clinical significance of serum calcium binding protein S100A8/A9 and soluble receptor for advanced glycation end products (sRAGE) levels in patients with chronic obstructive pulmonary disease(COPD).@*Methods@#Enzyme-linked immonosorbent assay was established to detect serum levels of S100A8/A9 and sRAGE in 203 patients with COPD[male166, female 37, aged 52-92 years, average years(69.72±9.079)] and in 41 smoking elderly non-COPD patients[male 35,female 6, aged 55-89 years, average years(68.66±8.74)], and 167 non-smoking healthy subjects as the control group[male 132, female 35, aged 57-92 years, average years(69.13±7.21)] from April 2018 to January 2019. The relationship between the S100A8/A9, sRAGE and clinical biomarkers [the percentage of fored expiratory volume in one second(FEV1) in the predicted value, FEV1/fored vital capacity(FVC), neutrophile granulocyte(NEU)%, pack-year] were investigated. The diagnostic value of S100A8/A9, sRAGE and their combined detection for COPD was analyzed using the subject operating characteristic curve.@*Results@#The serum S100A8/A9 level [(2.70±1.11)μg/ml] in COPD patients was significantly higher than that in the smoking control group [(1.65±0.63) μg/ml] and the non-smoking control group[(0.99±0.48)μg/ml], t=5.807, P<0.000 1; t=18.45, P<0.000 1. The serum S100A8/A9 levels in patients with COPD[GOLD Ⅰ(2.08±1.08) μg/ml, GOLDⅡ (2.58±1.06) μg/ml, GOLD Ⅲ (2.69±1.12) μg/ml, GOLDⅣ (2.95±1.10)μg/ml] were significantly higher than the non-smoking control group(0.99±0.48)μg/ml, t=6.616, P<0.000 1; t=14.56, P<0.000 1; t=17.10, P<0.000 1; t=18.09, P<0.000 1.The serum sRAGE level [(0.29±0.25)ng/ml] in COPD patients was significantly higher than that in the smoking control group[(0.60±0.24)ng/ml] and the non-smoking control group[(0.85±0.35)ng/ml], t=7.367, P<0.000 1; t=18.14, P<0.000 1. The serum sRAGE levels in patients with COPD[GOLD Ⅰ(0.46±0.40),GOLDⅡ (0.28±0.25),GOLD Ⅲ (0.29±0.25),GOLD Ⅳ (0.25±0.19)ng/ml] were significantly lower compared with non-smoking control group[(0.85±0.35)ng/ml], t=3.459, P=0.000 5; t=10.23, P<0.000 1; t=13.95, P<0.000 1; t=11.70, P<0.000 1. Serum S100A8/A9 levels were positively correlated with smoking amount and NEU% (r=0.458 5, P<0.000 1; r=0.228 3, P=0.001 1), negatively correlated with FEV1/FVC, the percentage of FEV1 in the predicted value, and sRAGE(r=-0.190 6, P=0.006 4; r=-0.186 3, P=0.007 8; r=-0.201 7, P=0.003 9). sRAGE levels were negatively correlated with NEU% (r=-0.155 9, P=0.026 4). In the ROC curve, the area under the curve of S100A8/A9, sRAGE and combined detection were 0.922[95%CI(0.897-0.947)], 0.926[95%CI(0.899-0.952)]and 0.966 [95%CI(0.950-0.983)], respectively.@*Conclusion@#S100A8/A9 and sRAGE are closely correlated with the degree of airflow constrains and the levels of serum inflammatory mediators, which are expected to be as potential biomarkers of COPD.
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Human airways contact with pathogen-associated molecular patterns and danger-associated molecular patterns present in many environments. Asthmatic's airways may be more susceptible to these patterns and lead to inflammasome activation; however, the participation of inflammasome in the development and exacerbation of asthma is not fully understood and remains controversial. Asthma is a heterogeneous group composed of different airway inflammation patterns with different underlying immune mechanisms. One mechanism is neutrophilic airway inflammation based on the axis of inflammasome activation, interleukin (IL) 1β/IL-18 production, T helper 17 activation, IL-8/IL-6 overproduction, and neutrophilic inflammation. The role of inflammasome activation has been highlighted in experimental asthma models and some evidence of inflammasome activation has been recently demonstrated in human neutrophilic asthmatic airways. In addition to caspase-1 activation, proteinase 3 and other protease from activated neutrophils directly cleave pro-IL-1β and pro-IL-18 to IL-1β and IL-18, which contribute to the phenotype of subsequent adaptive immune responses without inflammasome activation. Data suggests that neutrophilics in asthmatic airways may have an additional effect in initiating inflammasome activation and amplifying immune responses. Among the mediators from neutrophils, S100A9 seems to be one candidate mediator to explain the action of neutrophils in amplifying the airway inflammation in concert with inflammasome.