Introducing Transthyretin as a Differentially Expressed Protein in Washing Subtype of Obsessive-Compulsive Disorder.

INTRODUCTION: Obsessive-Compulsive Disorder (OCD) as one of the important mental problems is valuable topic for proteomic research studies to better understand the underlying mechanisms of this disorder. METHODS: In this paper, gel-based proteomic was used to investigate the proteome profile of 16 female patients with OCD, washing subtype before and after treatment with fluoxetine and comparing them with 20 healthy female controls. RESULTS: One of the abnormally expressed protein spots in this study was introduced and examined for protein-protein interaction network analysis via Cytoscape and its plug-ins. Transthyretin (TTR) protein showed significant expression changes (fold change=1.7, P<0.05). While the expression level of TTR is significantly decreased in OCD patients before any treatments, the trend is partially normalized after treatment with fluoxetine in positive responders. Furthermore, TTR interaction profile shows that the proteins interacting with this protein may get affected as this protein expression trend changes in OCD patients. CONCLUSION: TTR can be considered for further studies to be validated as a potential biomarker for OCD.

Could the endogenous opioid, morphine, prevent neural stem cell proliferation?

In spite of widespread use of morphine to treat pain in patients, little is known about the effects of this opioid on many cells including stem cells. Moreover the studies have been shown controversial results about morphine effects on several kinds of cells. It is well-known that morphine exposure could decrease testosterone levels in brain and spinal cord. Morphine could increase the activity of 5α-redutase, the enzyme that converts testosterone into its respective 5α-redutase derivative dihydrotestosterone (DHT). Also it could increase aromatase activity that converts testosterone to estradiol. Proliferation of neural stem cells was observed in human stem cells after exposure to certain combinations of steroids especially testosterone. On the other hand DHT has negative effect in neural stem cell reproduction. Morphine induces over-expression of p53 gene that could mediate stem cell apoptosis. Therefore we hypothesized that due to reduction in the testosterone levels, elevation in the DHT levels, and over-expression of p53 gene, morphine could prevent neural stem cell proliferation.