Correlation of Nr4a2 expression with the neuron progenitors in adult zebrafish brain.

Our previous study showed that although Nr4a2b transcripts have little co-localization with tyrosine hydroxylase (TH) in the posterior tuberculum area, knockdown of Nr4a2 caused a decrease in the number of TH-positive (TH(+)) neurons in the posterior tuberculum area. It suggests that Nr4a2 expression in the progenitors may play an important role in regulating differentiation rather than survival of TH(+) progenitors in the posterior tuberculum area during early zebrafish embryogenesis. In this study, we determined the correlation between TH and Nr4a2 in adult zebrafish brain and found that Nr4a2b was co-localized with the spindle-shaped TH(+) cells in the posterior tuberculum area and some small round TH(+) cells in the pretectum area, but not with large pear-shaped TH(+) cells in adult zebrafish diencephalon.

Collective roles of molecular chaperones in protein degradation pathways associated with neurodegenerative diseases.

The homeostasis of the protein synthesis and degradation is crucial for cell survival. Most age-related neurodegenerative diseases are characterized by accumulation of aberrant protein aggregates in affected brain regions. The principal routes of intracellular protein metabolism are the ubiquitin proteasome system (UPS) and the autophagy-lysosome pathway (ALP).

Nr4a2 is essential for the differentiation of dopaminergic neurons during zebrafish embryogenesis.

Nr4a2 is a member of the orphan nuclear receptor gene superfamily, which has been found to be critical for the development and maintenance of mesencephalic dopaminergic (DA) neurons. To uncover the molecular mechanisms by which Nr4a2 contributes to the development of DA neurons, we have applied zebrafish to study the topographic distribution of nr4a2b transcripts, as well as its correlation with neuronal progenitor marker (neurogenin 1) and DA neuron markers (tyrosine hydroxylase, TH and DA transporter, DAT) during neurogenesis. Our studies showed that although nr4a2b transcripts did not co-localize with TH and DAT transcripts in the posterior tuberculum (PT area), knockdown of Nr4a2 resulted in a significant decrease of TH(+) and DAT(+) DA neurons in the PT area, accompanied by a reduction of DA transmitter, which were partially rescued by the injection of mouse Nr4a2 mRNA.

Are heat shock proteins therapeutic target for Parkinson's disease?

Heat shock proteins (HSPs), known as molecular chaperone to assist protein folding, have recently become a research focus in Parkinson's disease (PD) because the pathogenesis of this disease is highlighted by the intracellular protein misfolding and inclusion body formation. The present review will focus on the functions of different HSPs and their protective roles in PD. It is postulated that HSPs may serve as protein folding machinery and work together with ubiquitin-proteasome system (UPS) to assist in decomposing aberrant proteins.

Estrogen provides neuroprotection against activated microglia-induced dopaminergic neuronal injury through both estrogen receptor-alpha and estrogen receptor-beta in microglia.

Estrogen provides neuroprotection against neurodegenerative diseases, including Parkinson's disease. Its effects may stem from interactions with neurons, astrocytes, and microglia. We demonstrate here in primary cultures of rat mesencephalic neurons that estrogen protects them from injury induced by conditioned medium obtained from lipopolysaccharide (LPS)-activated microglia.