Abstract P622: Regulation of Neuroprotective Myeloid Cell Leukemia 1 by Rapamycin and AT2R Agonists in Dopaminergic Neuronal Cell-line

Abstract

Myeloid Cell Leukemia I (MCL-1) is a critical protein for neuronal cell survival. MCL-1 is one of the anti-apoptotic proteins in the Bcl2 family. In neurons, MCL-1 regulates the rate of programmed cell death during development and after neuronal damage. It is now well established that without sufficient MCL-1 dopaminergic neuronal cells succumb to cell death under conditions of oxidative stress that result in neurodegenerative diseases such as Parkinsonism. Therefore, identifying drugs that can up-regulate the expression of MCL-1 in neuronal cells is critical for enhancing neuronal resistance to oxidative stress and improving neuronal survival. Aim of this study was to evaluate the effects of treatments with Rapamycin and a novel AT2R peptide agonist NP-6A4 on the MCL-1 expression in SH-SY5Y neuronal cell line. SH-SY5Y cells are a human-derived in vitro model of neuronal function and differentiation, expressing both adrenergic and dopaminergic markers. This cell line is a highly translational model for Parkinson's disease. Cells were maintained in a 1:1 mixture of DMEM and Ham's F-12 with 10% FBS. Cells were subjected to serum starvation and were treated with Rap (10nM), NP-6A4 (300nM) or their combination for 6 hours. MCL-1 protein expression was assessed by immunofluorescence using anti-MCL-1 antibody and a fluorophore-conjugated secondary antibody. Cells were imaged using a confocal microscope and fluorescence was quantified using Leica LAS AF software. It was observed that Rap treatment significantly suppressed MCL-1 expression in SH-SY5Y cells (~40% suppression, p<0.001), whereas Rap+NP-6A4 treatment reversed the Rap-mediated suppression of MCL-1 (p<0.0002). This data indicates that Rapamycin suppresses MCL-1 in dopaminergic neuronal cells and AT2R agonist, NP-6A4 is capable of reversing this effect.