Introduction: Amyloid plaques, mainly comprising of amyloid-beta peptides derived from its precursor protein, are found deposited in hippocampal and entorhinal cortical regions of patients with Alzheimer’s disease (AD). However, none led to a complete understanding of the molecular mechanisms of the AD in order to generate a new therapy that would eradicate the disease effectively. Activation of pro-apoptotic pathway was found to be associated with the accumulation of amyloid precursor protein (APP). The objective of this study is to examine theeffects of APP overexpression on the Bcl-2 family proteins involving in pro-apoptotic pathway in neuronal cells. Methods: The experiment was first performed with the transfection of HEK 293T cells for generation of lentiviral vector system consisting APP plasmid followed by transduction of SH-SY5Y neuronal cells using lentivirus generated. Subsequently, western blot analysis was conducted to validate the APP overexpression in SH-SY5Y cells. Then, expression levels of Bcl-2 family proteins in the APP overexpressed cells were determined by western blot analysis. The statistical analysis was performed by Microsoft Excel with Student’s t-test. Results: APP overexpression in SH-SY5Y cells slightly upregulated the pro-apoptotic proteins including Bad, Bid, Bok and Puma but slightly downregulated Bcl-2, Bim and Bax. Conclusion: Our data suggest that APP overexpression regulated the Bcl-2-mediated pathway by a significant downregulation of Bim protein in neuronal cells.
Introduction: The aging process is the most significant risk factor for developing Alzheimer’s disease (AD). AD is the most common neurodegenerative disease that causes cognitive and memory impairment in the elderly. Excessive build-up of amyloid protein leads to cell death, brain atrophy, and cognitive and functional decline in AD. The nuclear factor kappa beta (NF-κB) is a family of inducible transcription factors composed of NF-κB1, NF-κB2, RelA, RelB and c-Rel. It is activated by genotoxic agents, as well as oxidative and inflammatory stresses. It regulates expression of genes that control apoptosis, cell cycle progression, cell senescence, and inflammation. NF-κB regulates amyloid precursor protein (APP) processing by activating transcription of β and γ secretases, which promotes amyloid dysregulation in AD. In addition, NF-κB activation is linked with many of the known lifespan regulators including insulin/IGF- 1, FOXO, SIRT, and mTOR. Therefore, NF-κB pathway contributes to the pathophysiology of AD. This study aims to evaluate the effects of APP overexpression on NF-κB pathway in neuronal cells. Methods: SH-SY5Y neuronal cells were transduced with APP plasmid. Overexpression of APP in the cells was validated by western blotting. Western blot analysis using antibodies targeting NF-κB signalling pathway was performed using the APP-overexpressed cells. Results: Overexpression of APP in cells caused a significant down-regulation of phosphorylated NF-κB. Overexpression of APP also slightly up-regulated IkappaB-alpha, IKK alpha, and IKK beta. Conclusion: APP overexpression affected NF-κB pathway by down-regulating NF-κB protein.
Routine surveillance on resistant status of field mosquito populations is important to implement suitable strategies in order to prevent pest outbreaks. WHO test kit bioassay is the most frequent bioassay used to investigate the susceptibility status of field-collected mosquitoes, as it is relatively convenient to be carried out in the field. In contrast, the topical application of active ingredient is less popular in investigating the susceptibility status of mosquitoes. In this study, we accessed the susceptibility status of Aedes albopictus Skuse collected from two dengue hotspots on Penang Island: Sungai Dua and Persiaran Mayang Pasir. Two active ingredients: permethrin and deltamethrin, were used. WHO test kit bioassay showed that both wild strains collected were susceptible to the two active ingredients; while topical application assay showed that they were resistant. This indicated that WHO test kit bioassay less sensitive to low level of resistance compared to topical application assay. Hence, topical application is expected to be more indicative when used in a resistance surveillance programme.