In the nervous system, neurons contact each other to form neuronal circuits and drive behavior, relying heavily on synaptic connections. The proper development and growth of synapses allows functional transmission of electrical information between neurons or between neurons and muscle fibers. Defects in synapse-formation or development lead to many diseases. Autophagy, a major determinant of protein turnover, is an essential process that takes place in developing synapses. During the induction of autophagy, proteins and cytoplasmic components are encapsulated in autophagosomes, which fuse with lysosomes to form autolysosomes. The cargoes are subsequently degraded and recycled. However, aberrant autophagic activity may lead to synaptic dysfunction, which is a common pathological characteristic in several disorders. Here, we review the current understanding of autophagy in regulating synaptic development and function. In addition, autophagy-related synaptic dysfunction in human diseases is also summarized.
OBJECTIVE Previously we demonstrated the neuroprotective effect of 5-lipoxygenase(5-LOX)inhibitor as well as cysteinyl leukotriene receptor 1(Cys LT1)antagoniston rotenone-induced microglial activation and neuronal death.In this study,we determined the effects of 5-LOX inhibitor zileuton and Cys LT1 antagonist montelukast on neurotoxicity induced by 1-methyl-4-phenylpyridine(MPP+)in an in vitro model of Parkinson disease(PD).METHODS The neurotoxicity of MPP+,a neurotoxin relevant to PD,on the PC12 cells was measured by MTT assay,lactate dehydrogenase(LDH)release and double fluorescence staining with Hoechst/propidiumiodide(PI).The protective effects of 5-LOX inhibitor zileuton and Cys LT1 antagonist montelukast were investigated by the above methods.RESULTS We found that exposure of PC12 cells to MPP+led to a reduced cell viability and an increased level of LDH in a concentration-dependent manner.Pretreatment with zileuton and montelukast significantly attenuated viability loss and LDH release in MPP+-treated PC12 cells.Furthermore,MPP+increasednecrotic cell death in PC12 cells.Administration of montelukast significantly decreased MPP+-induced cell necrosis in PC12 cells.CONCLUSION The 5-LOX inhibitor zileuton and Cys LT1 antagonist montelukast have a neuroprotective effects on MPP+-induced neurotoxicity in PC12 cells.The 5-LOX inhibitor and Cys LT1 antagonist might raise a possibility as potential therapeutic agent for PD and other inflammation-related the central nervous system disorders.
