Transient neuroprotection by SRY upregulation in dopamine cells following injury in males — ASN Events

Transient neuroprotection by SRY upregulation in dopamine cells following injury in males (#303)

Vincent Harley 1 , Daniel P Czech 1 , Joohyung Lee 1 , Jeanne Correia 1 , Hannah Loke 1 , Eva K Möller 1
  1. MIMR-PHI Institute, Clayton, VIC, Australia

Emerging evidence suggest sex-specific regulation of dopamine neurons may underlie susceptibility of males to disorders such as Parkinson’s disease (PD). In healthy male dopamine neurons, the Y-chromosome gene product, the sex-determining region on the Y chromosome (SRY) modulates dopamine biosynthesis and motor function. We investigated the regulation and function of SRY in a model of dopamine cell injury. Treatment with the dopaminergic toxin, 6-hydroxydopamine (6-OHDA), significantly elevated SRY mRNA expression (9-fold) inhumanmaledopamineM17cells. SRY up-regulation occurred via the p-quinone pathway, associated with a 3.5-fold increase in expression of GADD45_, a DNA damage inducible factor gene and known SRY regulator. In turn, a signaling cascade involvingGADD45_/p38-MAPK/GATA activated the SRY promoter. Knockdown of SRY mRNA in 6-OHDA-treated M17 cells was deleterious, increasing levels of reactive oxygen species (ROS), pro-apoptotic marker PUMA mRNA, and cell injury (_25%, _32% and _34%, respectively). Conversely, ectopic over-expression of SRY in 6-OHDA-treated female SH-SY5Y cells was protective, decreasing ROS, PUMA, and cell injury (_40%, _46%, and _30%, respectively). However, the 6-OHDA-induced increase in SRY expression was diminished with higher concentrations of toxins or with chronic exposure to 6-OHDA. We conclude that SRY upregulation after dopamine cell injury is initially a protective response in males, but diminishes with gradual loss in dopamine cells. We speculate that dysregulation of SRY may contribute the susceptibility of males to PD.

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