Theasaponin E1 Attenuate Amyloid Beta(A?) Proteins and Hyperphosphorylated Tau in Sweapp N2a and Shy-5Y Cells By Down or up-Regulation of the Associated Signaling Molecules and Enzymes

In present study we investigated the therapeutic effects of green tea seed isolated theasaponin E1on attenuating Alzheimer by ameliorating the Aβ and tau level in SweAPP N2a cells and SHY-5Ycells. For reducing Aβ, the inhibition of β, γ-secretases and acetylcholinesterase and activation of α-secretase (ADAM10), neprilysin and insulin degrading enzyme (IDE) was investigated. In order to determine the inhibitory or activating effects of theasaponin E1 on tau, we targeted the signaling proteins involved in tau phosphorylation and dephosphorylation (Gsk-3β, Cdk5, MARK, Jnk, Akt, CaMKII AMPK/ERK, PP1, PP2-A and PP2-B). investigation was done with fluorometric assays, RT-PCR, Western blotting and ELISA respectively. Theasponin E1 was extracted and purified from green tea seed extract via HPLC. Cultured cells after treating with various concentrations were then processed for extraction of RNA, proteins and cell lysate which was then used for fluorometric assays, RT-PCR, Western blotting and ELISA respectively. Gen specific primers were used for amplification of the target genes and specific antibody for each terget were used for expression and quantification of the proteins. Our results demonstrated that theasaponin E1 significantly reduced Aβ concentration by activation of α-Secretase (over expression of ADAM10) and neprilysin. Activities of β secretase and γ-secretase were reduced in dose-dependent manner due to down-regulation of BACE1, Presenilin (PS1) and Nicastrin (NCT) respectively. NCT inhibition was lower as compared to PS1 also theasaponin E1 significantly reduce the activities of acetylcholinesterase. Theasaponin E1 effectively inhibit tau phosphorylation in dose dependent manner via downregulating Gsk-3β, Cdk5, MARK, Jnk, CaMKII.