Oral Presentation 6th Australian Health and Medical Research Congress 2012

Modeling neuroinflammation in Parkinson’s disease using pluripotent stem cell-derived human midbrain dopaminergic neurons  (#122)

Brigham J Hartley 1 , Brad Watmuff 1 , Ben A Finnin 1 , Stewart A Fabb 1 , Colin W Pouton 1 , John M Haynes 1
  1. Monash University, Parkville, Vic, Australia

Studies of neuronal degeneration in Parkinson’s disease (PD) are typically conducted on post mortem tissue or in animal models of disease.  This post-mortem tissue, often at the end stage of disease, provides limited insight into the mechanisms of disease progression.  Rodent and primate models provide better resolution of the factors mediating disease progression, but whether they faithfully recapitulate human disease progression is unknown.  In addition, current animal models do not allow investigation of the effects of, and signaling pathways associated with the addition of specific neuromodulators, especially in real time.  Our lab has generated novel human pluripotent stem cell (hPSC) reporter cell lines to study the derivation of human midbrain dopaminergic (mbDA) neurons and the use of these neurons as in vitro models of PD.  Using reporter cell lines expressing EGFP under the control of regulatory elements of the LIM homeobox transcription factor 1 alpha (LMX1A) and paired-like homeodomain transcription factor (PITX3), markers of committed mbDA neurons, in conjunction with a highly reproducible monolayer differentiation protocol (75.46 % ± 11.54 TH+PITX3+ neurons), that recapitulates mdDA development we have demonstrated the generation of functional mbDA neurons.  Functionally mature PITX3-EGFP+ are sensitive to the effects of 1-methyl-4-phenylpyridinium (MPP+, 42.64 % ± 2.96 survival, p<0.05), a parkinsonian neurotoxin, in a concentration-dependent manner.  A 72 hr treatment with tumor necrosis factor α (TNFα), a pro-inflammatory cytokine released by microglia, induces a reduction in both neurite length and PITX3-EGFP+ cell survival (63.95%  ± 0.05 survival, P<0.05). This is the first study to model neuroinflammation in hPSC-derived bonafide mbDA population. Dissecting the TNFα signaling pathway(s) that promote PITX3-EGFP+ mbDA neuronal death should facilitate the identification of pro-death and pro-survival signaling pathways that contribute to the rate of on-going degeneration in PD.