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The purpose of our study was to investigate the protective effects of a natural product—‘curcumin’— in Alzheimer's disease (AD)-like neurons. Although much research has been done in AD, very little has been reported on the effects of curcumin on mitochondrial biogenesis, dynamics, function and synaptic activities. Therefore, the present study investigated the protective effects against amyloid ß (Aß) induced mitochondrial and synaptic toxicities. Using human neuroblastoma (SHSY5Y) cells, curcumin and Aß, we studied the protective effects of curcumin against Aß. Further, we also studied preventive (curcumin+Aß) and intervention (Aß+curcumin) effects of curcumin against Aß in SHSY5Y cells. Using real time RT-PCR, immunoblotting and immunofluorescence analysis, we measured mRNA and protein levels of mitochondrial dynamics, mitochondrial biogenesis and synaptic genes. We also assessed mitochondrial function by measuring hydrogen peroxide, lipid peroxidation, cytochrome oxidase activity and mitochondrial ATP. Cell viability was studied using the MTT assay. Aß was found to impair mitochondrial dynamics, reduce mitochondrial biogenesis and decrease synaptic activity and mitochondrial function. In contrast, curcumin enhanced mitochondrial fusion activity and reduced fission machinery, and increased biogenesis and synaptic proteins. Mitochondrial function and cell viability were elevated in curcumin treated cells. Interestingly, curcumin pre- and post-treated cells incubated with Aß showed reduced mitochondrial dysfunction, and maintained cell viability and mitochondrial dynamics, mitochondrial biogenesis and synaptic activity. Further, the protective effects of curcumin were stronger in pretreated SHSY5Y cells than in post-treated cells, indicating that curcumin works better in prevention than treatment in AD-like neurons. Our findings suggest that curcumin is a promising drug molecule to treat AD patients.

The purpose of our study was to investigate the protective effects of a natural product—‘curcumin’— in Alzheimer's disease (AD)-like neurons. Although much research has been done in AD, very little has been reported on the effects of curcumin on mitochondrial biogenesis, dynamics, function and synaptic activities. Therefore, the present study investigated the protective effects against amyloid β (Aβ) induced mitochondrial and synaptic toxicities. Using human neuroblastoma (SHSY5Y) cells, curcumin and Aβ, we studied the protective effects of curcumin against Aβ. Further, we also studied preventive (curcumin+Aβ) and intervention (Aβ+curcumin) effects of curcumin against Aβ in SHSY5Y cells. Using real time RT-PCR, immunoblotting and immunofluorescence analysis, we measured mRNA and protein levels of mitochondrial dynamics, mitochondrial biogenesis and synaptic genes. We also assessed mitochondrial function by measuring hydrogen peroxide, lipid peroxidation, cytochrome oxidase activity and mitochondrial ATP. Cell viability was studied using the MTT assay. Aβ was found to impair mitochondrial dynamics, reduce mitochondrial biogenesis and decrease synaptic activity and mitochondrial function. In contrast, curcumin enhanced mitochondrial fusion activity and reduced fission machinery, and increased biogenesis and synaptic proteins. Mitochondrial function and cell viability were elevated in curcumin treated cells. Interestingly, curcumin pre- and post-treated cells incubated with Aβ showed reduced mitochondrial dysfunction, and maintained cell viability and mitochondrial dynamics, mitochondrial biogenesis and synaptic activity. Further, the protective effects of curcumin were stronger in pretreated SHSY5Y cells than in post-treated cells, indicating that curcumin works better in prevention than treatment in AD-like neurons. Our findings suggest that curcumin is a promising drug molecule to treat AD patients.

The binding of transcription factors to the core promoter of the juvenile hormone esterase gene was functionally characterized using both a cell-free in vitrotranscription functional assay and a cell transfection assay. A core JHE promoter (-61 to +28 bp relative to transcription start site) supported faithful transcription from the in vivo transcription start site. The nuclear extracts from the Sf9 insect cell line that provided transcription from that template also bound to that template as a probe in gel-mobility shift assays. Deletion or transversion of the initiator-binding motif (-1 to +4 bp) abolished detectable transcription either in vitro or in transfected cells. An AT-rich motif (ATATAT; -28 to -23 bp) serves another transcription factor-binding site. Mutation of the AT-rich motif to a canonical TATA-box preserved transcription, while either its deletion or complete transversion abolished or significantly reduced detectable transcriptional activity. These results indicate that, under these conditions, the functional operation of this core promoter approaches that of a composite promoter in which both the TATA- and initiator-binding protein complexes are necessary, even for basal transcription. On the other hand, these debilitating mutations to either the TATA box or initiator motif did not prevent the ability of the corresponding gel-shift competitive probes to compete with the wild-type promoter for binding by the transcription factors. Even a double transversion of both the AT-rich motif and the initiator-binding motif was able to competitively displace the protein complex that bound to the labelled wild-type probe. These data strongly indicate the presence of (an) additional core-promoter-associated transcription factor(s) (that is not the ‘downstream element ’) that contact(s) the AT-binding complex and/or initiator-binding factor with sufficient avidity to remove them from binding to the competing wild-type promoter sequence.