The hTH-GFP Reporter Rat Model for the Study of Parkinson's Disease

Lorraine Iacovitti, Xiaotao Wei, Jingli Cai, Eric W. Kostuk, Ruihe Lin, Alexander Gorodinsky, Philip Roman, Gretchen Kusek, Sonal S. Das, Audrey Dufour, Terina N. Martinez, Kuldip D. Dave (+1 others)
2014 PLoS ONE  
Parkinson disease (PD) is the second leading neurodegenerative disease in the US. As there is no known cause or cure for PD, researchers continue to investigate disease mechanisms and potential new therapies in cell culture and in animal models of PD. In PD, one of the most profoundly affected neuronal populations is the tyrosine hydroxylase (TH)-expressing dopaminergic (DA) neurons of the substantia nigra pars compacta (SNpc). These DA-producing neurons undergo degeneration while neighboring
more » ... -producing cells of the ventral tegmental area (VTA) are largely spared. To aid in these studies, The Michael J. Fox Foundation (MJFF) partnered with Thomas Jefferson University and Taconic Inc. to generate new transgenic rat lines carrying the human TH gene promoter driving EGFP using a 11 kb construct used previously to create a hTH-GFP mouse reporter line. Of the five rat founder lines that were generated, three exhibited high level specific GFP fluorescence in DA brain structures (ie. SN, VTA, striatum, olfactory bulb, hypothalamus). As with the hTH-GFP mouse, none of the rat lines exhibit reporter expression in adrenergic structures like the adrenal gland. Line 12141, with its high levels of GFP in adult DA brain structures and minimal ectopic GFP expression in non-DA structures, was characterized in detail. We show here that this line allows for anatomical visualization and microdissection of the rat midbrain into SNpc and/ or VTA, enabling detailed analysis of midbrain DA neurons and axonal projections after toxin treatment in vivo. Moreover, we further show that embryonic SNpc and/or VTA neurons, enriched by microdissection or FACS, can be used in culture or transplant studies of PD. Thus, the hTH-GFP reporter rat should be a valuable tool for Parkinson's disease research. remains the 6-hydroxydopamine (6-OHDA) lesioned rat, first described by Ungerstedt [8]. Because of the larger size of the rat brain as compared to the mouse brain, this model allows local administration of toxin unilaterally into the SNpc, striatum or median forebrain bundle (MFB), resulting in ipsilateral motor deficits which can be assessed, quantified, and compared to the contralateral side over time and following various experimental treatments. Because of the ease and reliability of this behavioral model [9, 10] , it has been long-favored by researchers. However, until now, there has been no transgenic reporter rat line to facilitate these studies in vivo or in vitro. The Michael J. Fox Foundation (MJFF) has developed a strategy to directly sponsor the generation, phenotypic characterization and distribution of preclinical rodent models in order to aid and accelerate PD research [11] . As part of this overall strategy, MJFF, partnered with Thomas Jefferson University and Taconic Inc. to generate new transgenic rat lines carrying 11 kb of the human TH gene promoter driving EGFP [5] . With its high levels of GFP, hTH-GFP rat reporter line 12141 allows for anatomical visualization of the rat SNpc and/or VTA and detailed analysis of midbrain DA neurons and axonal projections after toxin treatment in vivo. Moreover, embryonic microdissection of fluorescent SNpc and/or VTA greatly enriches the proportion of DA neurons that can be isolated from each of these midbrain regions for culture and transplant studies. With further FACS analysis, DA neurons from each of these regions can be purified to near homogeneity. Thus, the hTH-GFP reporter rat should be a valuable tool for Parkinson disease research.
doi:10.1371/journal.pone.0113151 pmid:25462571 pmcid:PMC4251919 fatcat:crnowjf4f5fobmyunz3bwzegsy