OBJECTIVE: To investigate expression of Semaphorin 3A in rats after spinal cord injury and explore possible mechanism of inhibiting of axonal regeneration after SCI. METHODS: Forty healthy female SD rats, 8 weeks old, weighing (210.00±9.88) g, were randomly divided into control group(20 rats in group A) and model group(20 rats in group B). In control group, removal of T RESULTS: After a simple spinal cord transection injury, hemorrhagic necrosis, localized edema, neurodegeneration, necrosis, and cyst formation occurred in the injured area, and glial scar formation occurred in glial cells. Semaphorin 3A expression levels in control group was low in the gray matter area. There was no expression of Semaphorin 3A in the injured area of spinal cord injury in model group 3 days after operation. On the 14th day, the expression of Semaphorin 3A in the injured area of spinal cord injury increased significantly and was at a high level. On the 28th day, the expression of Semaphorin 3A was moderate. On the 42th day, the positive expression of Semaphorin 3A returned to normal level. CONCLUSION The increased expression of Semaphorin 3A after spinal cord injury may be one of the mechanisms that inhibit axonal regeneration.
Animals ; Female ; Rats ; Rats, Sprague-Dawley ; Semaphorin-3A/genetics* ; Spinal Cord ; Spinal Cord Injuries/genetics*

BACKGROUNDMaintenance of normal cardiac function is controlled by the autonomic nervous system. In congestive heart failure (CHF), sympathetic nerve denervation is increasingly recognized. The sympathetic fiber density depends on the balance between neurotrophins and neural guidance molecules. Semaphorin 3A (sema3a), a secreted neural guidance factor, is a well characterized member of the newly found semaphorin family. It can induce sympathetic growth cone collapse and axon repulsion. We conducted this study to investigate cell sources of sema3a in the heart, the expression level of sema3a in CHF and discuss the possible role of sema3a in CHF.

METHODSRats were divided into four groups: 30 days control group rats, 30 days CHF rats, 60 days control group rats, 60 days CHF rats. The heart failure model was induced by injection of isoproterenol (ISO) 340 mg/kg continuously two days. All animals underwent echocardiography and haemodynamics measurements. Cardiac expression of sema3a was determined by real time polymerase chain reaction (RT-PCR) and Western blotting analysis. Immunohistochemical analysis was used to determine the cell source of sema3a in the heart.

RESULTSIsoproterenol induced 30 days and 60 days CHF rats displayed left ventricular dilation, systolic and diastolic function decrease. Sema3a was secreted by the cardiocytes and increased significantly in 30 days and 60 days CHF rats compared with the controls (RT-PCR: 30 days group: 0.32 ± 0.05 vs. 0.58 ± 0.06, P < 0.01; 60 days group: 0.34 ± 0.08 vs. 0.71 ± 0.07, P < 0.01. Western blotting: 30 days group: 0.25 ± 0.10 vs. 0.46 ± 0.10, P < 0.05; 60 days group: 0.29 ± 0.10 vs. 0.55 ± 0.16, P < 0.01. Immunohistochemical analysis: 30 days group: 2.91 ± 0.20 vs. 5.31 ± 0.30, P < 0.01; 60 days group: 2.94 ± 0.30 vs. 5.80 ± 0.30, P < 0.01).

CONCLUSIONSSema3a was expressed in the heart by cardiocytes. Increased expression of sema3a may partly account for sympathetic denervation in CHF; modulation of this pathway may prove beneficial in heart failure sympathetic remodeling.

Animals ; Blotting, Western ; Echocardiography ; Heart Failure ; chemically induced ; metabolism ; Hemodynamics ; drug effects ; Immunohistochemistry ; Isoproterenol ; toxicity ; Male ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Real-Time Polymerase Chain Reaction ; Semaphorin-3A ; genetics ; metabolism

OBJECTIVETo investigate the effects of tumor cell-derived Sema3A on the immunological functions of murine dendritic cells (DCs).

METHODSLung adenocarcinoma A549 cells were transfected with small interference RNA, Si-Sema and Si-mut, and the interference efficiency was determined by real-time PCR and Western-blot. The concentrated supernatants from cultured tumor cells, Si-Sema and Si-mut-infected tumor cells were subjected to DCs respectively. The immunophenotypes of DCs were analyzed by flow cytometry, the production of IL-12P70 and the ability of DCs to stimulate DO11. 10 T cells secreting IFN-gamma and IL-2 were detected by enzyme linked immunosorbent assay (ELISA).

RESULTSKnockdown with Si-Sema3A significantly decreased the secretion of Sema3A by A549 cells in comparison with the Si-mut cells. DCs exposed to supernatants from Si-Sema cells showed elevated levels of MHC, CD40 and CD80, more production of IL-12P70, and enhanced capability of activating antigen-specific T cells, as evidenced by the remarkably increased levels of IFN-gamma and IL-2.

CONCLUSIONA549 cells secrete Sema3A to inhibit the maturation and functions of DCs, which might be associated with the unidentified mechanism of immune evasion by tumor cells.

Animals ; Cell Line, Tumor ; Dendritic Cells ; drug effects ; immunology ; Female ; Humans ; Lung Neoplasms ; immunology ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Semaphorin-3A ; genetics ; metabolism ; pharmacology ; Transfection ; Tumor Escape ; immunology

Neuropilin 1 (NP1) is a part of essential receptor complexes mediating both semaphorin3A (SEMA3A) and vascular endothelial growth factor (VEGF) which is one of important mediators involved in the pathogenesis of asthma. Therefore, it is possible that SEMA3A plays a role in the pathogenesis of asthma through attenuation of VEGF-mediated effects. In the present study, we aimed to evaluate expression levels of SEMA3A and NP1 using induced sputum of asthmatics and a murine model of asthma. Firstly, SEMA3A and NP1 expressions in induced sputum of asthmatics and SEMA3A and NP1 expression on bronchoalveolar lavage (BAL) cells and lung homogenates of asthmatic mice were determined. Then we evaluated the immunolocalization of VEGF receptor 1 (VEGFR1), VEGF receptor 2 (VEGFR2), and NP1 expressions on asthmatic mice lung tissue and their subcellular distributions using fibroblast and BEAS2B cell lines. Sputum SEMA3A and NP1 expressions were significantly higher in asthmatics than controls. Similarly, SEMA3A and NP1 expressions on BAL cells and lung homogenates were significantly elevated in asthmatic mice compared to control mice. Immunohistochemical analysis showed that VEGFR1, VEGFR2, and NP1 expressions were also uniformly increased in asthmatic mice. Our observations suggest that SEMA3A and NP1 may play important roles in the pathogenesis of asthma.
Animals ; Asthma/metabolism/pathology/*physiopathology ; Bronchoalveolar Lavage Fluid/cytology ; Cell Line ; Disease Models, Animal ; Female ; Fibroblasts/metabolism ; *Gene Expression Regulation ; Immunohistochemistry ; Lung/metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Neuropilin-1/*genetics/metabolism ; Semaphorin-3A/*genetics/metabolism ; Sputum/metabolism ; Vascular Endothelial Growth Factor Receptor-1/metabolism ; Vascular Endothelial Growth Factor Receptor-2/metabolism