Nicotine and menthol independently exert neuroprotective effects against cisplatin-or amyloid-toxicity by upregulating Bcl-xl via JNK activation in SH-SY5Y cells

Nicotine and menthol,agonists of nicotinic acetylcholine receptor(nAChR)and transient receptor potential melastatin type 8(TRPM8),serve important roles in the prevention of cell death-involved neurodegenerative diseases.However,the potential synergistic effects of nicotine and menthol on anti-apoptotic ability are still uncertain.In the present study,the potential synergistic effects of nicotine and menthol on cisplatin or amyloidβ1-42 induced cell model of the neurodegenerative diseases were explored by assessing cell viability,TNF-αexpression,caspase-3 activation,and the collapse of mitochondrial membrane potential in human SH-SY5Y neuroblastoma cells.Statistical significance was tested using Student’s t-test or one-way ANOVA with post hoc Newman-Keuls test.The results showed that:Firstly,SH-SY5Y cell viability was obviously increased by the treatments with nicotine and menthol.Secondly,nicotine and menthol independently alleviated cisplatin or amyloidβ1-42 induced TNF-αup-regulation.Thirdly,nicotine and menthol abrogated the effect of cisplatin and amyloidβ25-35 on caspase-3 activation.Interestingly,the effect of cisplatin and amyloidβ1-42 on the collapse of mitochondrial membrane potential was efficiently attenuated by nicotine and menthol treatments.Most importantly,the inhibition of c-jun kinase(JNK)activation abolished the effect of cisplatin,and amyloidβ1-42 stimulated Bcl-xl expression.All these findings indicate that nicotine and menthol independently exert neuroprotective effects by upregulating Bcl-xl via JNK activation.Nicotine and menthol augmented Bcl-xl expression and JNK phosphorylation,and thus they are potential therapeutic targets for altering the progress of neurodegenerative diseases.

Dysfunction of Murine Dendritic Cells Induced by Incubation with Tumor Cells

In vivo studies showed that dendritic cell （DC） dysfunction occurred in tumor microenvironment. As tumors were composed of many kinds of cells, the direct effects of tumor cells on immature DCs （imDCs） are needed for further studies in vitro. In the present study, bone marrow-derived imDCs were incubated with lymphoma, hepatoma and menaloma cells in vitro and surface molecules in imDCs were determined by flow cytometry. Then, imDCs incubated with tumor cells or control imDCs were further pulsed with tumor lysates and then incubated with splenocytes to perform mixed lymphocyte reaction. The DC-dependent tumor antigen-specific T cell proliferation, and IL-12 secretion were determined by flow cytometry, and enzyme-linked immunosorbent assay respectively. Finally, the DC-dependent tumor-associated antigen-specific CTL was determined by enzyme-linked immunospot assay. The results showed that tumor cell-DC incubation down-regulated the surface molecules in imDCs, such as CD80, CD54, CDIIb, CDIIa and MHC class II molecules. The abilities of DC-dependent antigen-specific T cell proliferation and IL-12 secretion were also decreased by tumor cell incubation in vitro. Most importantly, the ability for antigenic-specific CTL priming of DCs was also decreased by incubation with tumor cells. In the present in vitro study demonstrated that the defective abilities of DCs induced by tumor cell co-incubation and the co-incubation system might be useful for future study of tumor-immune cells direct interaction and for drug screen of immune-modulation. Cellular ＆ Molecular Immunology.