OBJECTIVETo investigate the effects of mannan-binding lectin (MBL) on the functions of human polymorphonuclear cells (PMNs).

METHODSELISA and Dot blot were performed to examine the binding between MBL and the microorganisms. Flow cytometry and fluorescence microscopy were employed to analyze the phagocytosis of FITC-labeled microorganisms by the PMNs. Real-time quantitative PCR was used to detect the expression levels of IL-1β, TNF-α and CD11b mRNA in the PMNs, and ELISA used to detect the levels of TNF-α and IL-6 in the supernatants of PMN culture. Nitro-blue tetrazolium reduction assay was used to estimate the levels of superoxide production.

RESULTSMBL bound to the microorganisms in a dose-dependent manner. MBL had no significant effect on phagocytosis of C. albicans and E.coli by the PMNs in the absence of human serum, but in presence of mixed MBL-deficient human sera, MBL promoted the phagocytosis of C. albicans, which could be blocked by mannan. Mannan treatment increased the expressions of IL-1β, TNF-α, IL-6 and CD11b and enhanced superoxide production in the PMNs.

CONCLUSIONMBL can promote phagocytosis of microorganisms by PMNs and increase the expressions of proinflammatory cytokines from PMNs in a complement lectin pathway-dependent manner.

Candida albicans ; immunology ; Cells, Cultured ; Cytokines ; immunology ; Escherichia coli ; immunology ; Humans ; Mannose-Binding Lectin ; blood ; Neutrophils ; immunology ; Phagocytosis ; Superoxides ; immunology

[Abstract] Objective: To investigate the expression of tight junction protein claudin-7 (CLDN-7) in pancreatic cancer and its correlation with the clinicopathological features and prognosis of pancreatic cancer patients. Methods: Oncomine, GEPIA and GEO databases were used to comprehensively analyze the mRNA expression level of CLDN-7 in pancreatic cancer, and Kaplan-Meier Plotter database was used to analyze the relationship between the expression of CLDN-7 and the survival prognosis of pancreatic cancer patients. Immunohistochemical staining was used to detect the protein level of CLDN-7 in 44 cases of pancreatic cancer tissues and 31 cases of para-cancerous tissues resected in the Department of General Surgery of the Second Hospital of Lanzhou University from 2015 to 2018, and the relationship between CLDN-7 expression and clinicopathological characteristics and prognosis of patients was also analyzed. GO (Gene Ontology) analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis were conducted to analyze the possible signaling pathways that CLDN-7 may involve in and their main functions, which were further verified in TCGA and GEPIA databases. Results: Analysis of both the databases and the clinical samples showed that CLDN-7 was significantly over-expressed in pancreatic cancer tissues, and its high expression was correlated with clinical prognosis of pancreatic cancer patients; moreover, CLDN-7 expression was an independent factor affecting the overall survival time of pancreatic cancer patients (all P<0.05). GO analysis and KEGG pathway enrichment analysis confirmed that CLDN-7 was involved in DNA damage repair and glucose metabolism in pancreatic cancer patients. TCGA and GEPIA database validation showed that CLDN-7 expression in pancreatic cancer was significantly and positively correlated with the expression of DNA damage repair related genes (POLD4, SMUG1, NTHL1) and glucose metabolism related genes (ALDOA, TALDO1, PGLS) (all P<0.01). Conclusion: CLDN-7 is highly expressed in pancreatic cancer and indicates a worse clinical prognosis; moreover, CLDN-7 is associated with DNA damage repair and intratumoral glucose metabolism in pancreatic cancer.