Gelatin but not type I collagen promotes bacteria phagocytosis in PMA-treated U937 human lymphoma cells.

PURPOSE: Besides comprising scaffolding, extracellular matrix components modulate many biological processes including inflammation and cell differentiation. We previously found precoating cell plates with extracellular matrix collagen I, or its denatured product gelatin, causes aggregation of macrophage-like human lymphoma U937 cells, which are induced to differentiation by phorbol myristate treatment. In the present study, we investigated the influence of gelatin or collagen I precoating on the bacteria phagocytosis in PMA-stimulated U937 cells. MATERIALS AND METHODS: Colony forming units of phagocytosed bacteria, Giemsa-staining of cells with phagocytosed bacteria, confocal microscopic and flow cytometric analysis of cells with phagocytosed FITC-labeled bacteria and non-bioactive latex beats were conducted. RESULTS: Gelatin precoating enhances the phagocytosis of both Gram-negative and positive bacteria, as shown by the increased colony forming units of bacteria phagocytosed by cells, and increased intracellular bacteria observed after Giemsa-staining. But collagen I has no marked influence. Confocal microscopy reveals that both live and dead FITC-bacteria were phagocytosed more in the cells with gelatin-coating but not collagen-coating. Of note, both gelatin and collagen I coating had no influence on the phagocytosis of non-bioactive latex beads. Since gelatin-coating increases autophagy but collagen I has no such impact, we are curious about the role of autophagy. Inhibiting autophagy reduced the phagocytosis of bacteria, in cells with gelatin-coating, while stimulating autophagy enhanced phagocytosis. CONCLUSION: This study finds the bacteria-phagocytosis stimulatory effect of gelatin in PMA-treated U937 cells and reveals the positive regulatory role of autophagy, predicting the potential use of gelatin products in anti-bacterial therapy.

The impact of basketball on the social adjustment of Chinese middle school students: the chain mediating role of interpersonal relationships and self-identity.

Background: This study examines the effects of 12 weeks of basketball on interpersonal relationships, self-identity and social adjustment of middle school students, as well as exploring the mediating role of interpersonal relationships and self-identity in basketball's influence on social adjustment. Methods: A total of 87 students from a middle school in Jiangsu Province, China, were selected to participate in this study. A 12-week basketball intervention experiment was conducted, and questionnaires were administered to measure the study variables. Common method bias test, normality test, ANOVA and Pearson correlation analysis were used to analyze the study variables. The theoretical model of this study was also validated using the Process plug-in developed by Hayes, setting p < 0.05 (two-tail) as statistically significant. Results: After a 12-week basketball intervention experiment, the interpersonal relationships, self-identity and social adjustment of the middle school students in the experimental and control groups showed improvement, with the experimental group showing significantly more significant improvement than the control group. A 12-week basketball intervention can positively impact the social adjustment of middle school students, with interpersonal relationships and self-identity acting as a chain mediator in the impact process.