Human Amyloid-beta (1-43) ELISA kit

Cholesterol has been implicated in the pathogenesis of Alzheimer's disease ( AD). Although the underlying mechanisms are not yet clear, several studies have provided evidence for the involvement of cholesterol-rich lipid rafts in the production of amyloid beta peptide (A beta), the major component of amyloid deposits in AD. In this regard, the gamma-secretase complex is responsible for the final cleavage event in the processing of beta-amyloid precursor protein (beta APP), resulting in A beta generation. The gamma-secretase complex is a multiprotein complex composed of presenilin, nicastrin (NCT), APH-1, and PEN-2. Recent reports have suggested that gamma-secretase activity is predominantly localized in lipid rafts, and presenilin and NCT have been reported to be localized in lipid rafts. In this study, various biochemical methods, including coimmunoprecipitation, in vitro gamma-secretase assay, and methyl-beta-cyclodextrin (M beta CD) treatment, are employed to demonstrate that all four components of the active endogenous gamma-secretase complex, including APH-1 and PEN-2, are associated with lipid rafts in human neuroblastoma cells (SH-SY5Y). Treatment with statins, 3-hydroxy-3- methylglutaryl-CoA-reductase inhibitors, significantly decreased the association of the beta-secretase complex with lipid rafts without affecting the distribution of flotillin-1. This effect was partially abrogated by the addition of geranylgeraniol. These results suggest that both cholesterol and protein isoprenylation influence the active gamma-secretase complex association with lipid rafts.

Over activation of glial cell derived innate immune factors induces neuro-inflammation that results in neurodegenerative disease, like working memory impairment. In this study, we have investigated the role of andrographolide, a major constituent of Andrographis paniculata plant, in reduction of reactive glial cell derived working memory impairment. Real time PCR, Western bloting, flow cytometric and immunofluorescence studies demonstrated that andrographolide inhibited lipopolysaccharide (LPS)-induced overexpression of HMGB1, TLR4, NF kappa B, COX-2, iNOS, and release of inflammatory mediators in primary mix glial culture, adult mice prefrontal cortex and hippocampus region. Active microglial and reactive astrocytic makers were also down regulated after andrographolide treatment. Andrographolide suppressed overexpression of microglial MIP-1 alpha, P2X7 receptor and its downstream signaling mediators including-inflammasome NLRP3, caspasel and mature IL-1 beta. Furthermore, in vivo maze studies suggested that andrographolide treatment reversed LPS-induced behavioural and working memory disturbances including regulation of expression of protein markers like PKC, p-CREB, amyloid beta, APP, p-tau, synapsin and PSD-95. Andrographolide, by lowering expression of pro apoptotic genes and enhancing the expression of anti-apoptotic gene showed its anti-apoptotic nature that in turn reduces neurodegeneration. Morphology studies using Nissl and FJB staining also showed the neuroprotective effect of andrographolide in the prefrontal cortex region. The above studies indicated that andrographolide prevented neuroinflammation-associated neurodegeneration and improved synaptic plasticity markers in cortical as well as hippocampal region which suggests that andrographolide could be a novel pharmacological countermeasure for the treatment of neuroinflammation and neurological disorders related to memory impairment.