Design and in vitro analysis of SIRT2 inhibitor targeting Parkinson's disease

Inhibition of Sirtuin2 (SIRT2) protein rescues the α-synuclein toxicity in vitro and in vivo models of Parkinson's disease (PD). Thioacetyl group can structurally mimic the acetyl group and restrain the deacetylating p53 reaction by SIRT2. This work evaluated the biological activity of designed pentapeptides inhibitor containing N-thioacetyl-lysine against SIRT2. Pentapeptide by introducing thioacetyl-lysine as an inhibitor of SIRT2 was screened by molecular docking and synthesized by solid phase method. The inhibition of pure recombinant SIRT2 as well as SIRT2 in serum of PD patients by peptide was done by fluorescent activity assay. The inhibition of SIRT2 was assessed in PC12 cell line by measuring acetylated α-tubulin level. The peptide YKK(ε-thioAc)AM and HRK(ε-thioAc)AM were found to be SIRT2 inhibitors by molecular docking. However, YKK(ε-thioAc)AM was more specific towards SIRT2 than SIRT1 (Sirtuin1). It inhibited recombinant SIRT2 by IC₅₀ value of 0.15 µM and KD values 9.92 × 10^-8/M. It also inhibited serum SIRT2 of PD. It increased the acetylation of α-tubulin in PC12 neuroblastoma cells which is essential for maintaining the microtubular cell functions of brain. It can be concluded that novel peptide YKK(ε-thioAc)AM may be a platform for therapeutic agent for Parkinson's disease targeting SIRT2.