The integrity of chemically treated plasmid DNA as a chemical-based choice for prion clearance.

In regenerative medical products for clinical applications, a major concern is the risk of ruminant-derived materials developing transmissible spongiform encephalopathy (TSE) in the manufacturing process. Because of the risk of TSE causing prion disease, the raw materials derived from ruminants should be compliant with the "Standard for Biological Raw Materials" to ensure the quality and safety of pharmaceutical products. We therefore tested whether plasmid DNA could withstand four chemical reagents (Gdn-HCl, Gdn-SCN, TCA, or SDS), having referred to the report by Tateishi et al. [1], which describes how Creutzfeldt-Jakob disease pathogens can be inactivated by chemical reagents capable of producing a 7-log reduction in prion inactivation. We observed that plasmid DNA was mixed with chemical reagents and that the functionality of plasmid DNA was equivalent for both chemical and non-chemical treatment. The potency of plasmid DNA was monitored by the existence of DNA fragments and the function by which GFP proteins were produced by HEK293-cell transfected plasmid DNA. The existence of DNA fragments was detected in plasmid DNA treated by chemical reagents, except when undergoing TCA treatment. Additionally, when HEK293 cells were transfected with the plasmid DNA after chemical treatment, GFP protein was produced. These results indicate that plasmid DNA can withstand the chemical treatments for blocking prion transmission.

Chronic unpredictable mild stress-induced behavioral changes are coupled with dopaminergic hyperfunction and serotonergic hypofunction in mouse models of depression.

Accumulating evidence shows that stressful events evoke molecular alterations in the brain, considered a pathology in major depressive disorder (MDD). However, the abnormalities of neurotransmissions as well as intracellular signaling pathways affected by chronic stress in brain have not been fully explored. We investigated the effect of chronic unpredictable mild stress (CUMS) on the emotional behaviors, dopaminergic and serotoninergic function, and intracellular signaling in the nucleus accumbens, hippocampus and prefrontal cortex. Male C57BL/6J mice were exposed to CUMS for 4 weeks. CUMS was shown to induce hyperactivity in a novel environment, decrease interaction time in the social interaction test, prolong feeding latency in the novelty suppressed feeding test and enhance immobility in the forced swimming test. The levels of dopamine, its metabolites and turnover, and protein level of tyrosine hydroxylase (TH) were increased by CUMS in the nucleus accumbens (NAc). The level of serotonin and protein levels of tryptophan hydroxylase (TPH) and TH were decreased by CUMS in the hippocampus (HPC) and prefrontal cortex (PFC). Accompanying the increase in dopaminergic function, phosphorylation levels of extracellular signal-regulated kinases (ERK), protein kinase B (Akt) and cAMP response element-binding protein (CREB) were increased by CUMS in the NAc. Administration of fluoxetine (selective serotonin re-uptake inhibitor: 20 mg/kg i.p.) and aripiprazole (dopamine D2 receptor partial agonist: 0.1 mg/kg i.p.) during CUMS, prevented behavioral changes and increase of dopamine level in the NAc. These data suggest that CUMS-induced depression-like behaviors are coupled with dopaminergic hyperfunction in the NAc and serotonergic hypofunction in the HPC and PFC.

Changes in tryptophan metabolism during pregnancy and postpartum periods: Potential involvement in postpartum depressive symptoms.

BACKGROUND: Many women experience depressive symptoms during pregnancy and postpartum periods. These depressive symptoms are often accompanied by other inflammatory morbidities present during pregnancy. Tryptophan (TRP) metabolism has attracted considerable attention due to its influence on the onset of depression via induction of inflammation. We examined the changes in plasma levels of TRP metabolites in pregnant women with depressive symptoms during pregnancy and/or the postpartum period. METHODS: In line with a previous analysis using the Edinburgh Postnatal Depression Scale (EPDS), participants were divided into a non-depressive (ND) group, a postpartum depressive (PD) group, a temporary gestational depressive (TG) group, and a continuous depressive (CD) group. Blood samples were collected before and 1 month after delivery. The concentrations of plasma TRP metabolites were measured using high-performance liquid chromatography (HPLC). RESULTS: There are differences in plasma levels of TRP metabolites during pregnancy and postpartum periods between the ND group and the PD group, but not the TG or CD group. In the PD group, plasma levels of kynurenine (KYN) and kynurenic acid (KA), and KYN/TRP and KA/KYN ratio during the pregnancy period were higher and 3-hydroxyanthranilic acid (3HAA) during the postpartum period was lower than those in the ND group. LIMITATIONS: Histories regarding mood disorders before pregnancy were not assessed. CONCLUSIONS: The higher plasma levels of KYN and KA, and KYN/TRP and KA/KYN ratio during pregnancy period and lower plasma level of 3HAA during the postpartum period could be useful predictive and diagnostic markers of postpartum depressive symptoms.