Synthetic DNA nanopores for direct molecular transmission between lipid vesicles.

Lipid vesicles hold potential as artificial cells in bottom-up synthetic biology, and as tools in drug delivery and biosensing. Transmitting molecular signals is a key function for vesicle-based systems. One strategy to achieve this function is by releasing molecular signals from vesicles through nanopores. Nevertheless, in this strategy, an excess of molecular signals may be required to reach the targets, due to the dispersion of the signals during diffusion. The key to achieving the efficient utilization of signals is to shorten the distance between the sender vesicle and the target. Here, we present a pair of DNA nanopores that can connect and form a direct molecular pathway between vesicles. The nanopores are self-assembled from nine single DNA strands, including six 14-nucleotide single-stranded overhangs as sticky-end segments, enabling them to bind with each other. Incorporating nanopores shortens the distance between different populations of vesicles, allowing less diffusion of molecules into bulk solution. To further reduce the loss of molecules, a DNA nanocap is added to one of the nanopore's openings. The nanocap can be removed through the toehold-mediated DNA strand displacement when the nanopore meets its counterpart. Our DNA nanopores provide a novel molecular transmission tool to lipid vesicles-based systems.

Lipid vesicle-based molecular robots.

A molecular robot, which is a system comprised of one or more molecular machines and computers, can execute sophisticated tasks in many fields that span from nanomedicine to green nanotechnology. The core parts of molecular robots are fairly consistent from system to system and always include (i) a body to encapsulate molecular machines, (ii) sensors to capture signals, (iii) computers to make decisions, and (iv) actuators to perform tasks. This review aims to provide an overview of approaches and considerations to develop molecular robots. We first introduce the basic technologies required for constructing the core parts of molecular robots, describe the recent progress towards achieving higher functionality, and subsequently discuss the current challenges and outlook. We also highlight the applications of molecular robots in sensing biomarkers, signal communications with living cells, and conversion of energy. Although molecular robots are still in their infancy, they will unquestionably initiate massive change in biomedical and environmental technology in the not too distant future.

A Study of the Effects of Plasma Surface Treatment on Lipid Bilayers Self-Spreading on a Polydimethylsiloxane Substrate under Different Treatment Times.

Plasma-treated poly(dimethylsiloxane) (PDMS)-supported lipid bilayers are used as functional tools for studying cell membrane properties and as platforms for biotechnology applications. Self-spreading is a versatile method for forming lipid bilayers. However, few studies have focused on the effect of plasma treatment on self-spreading lipid bilayer formation. In this paper, we performed lipid bilayer self-spreading on a PDMS surface with different treatment times. Surface characterization of PDMS treated with different treatment times is evaluated by AFM and SEM, and the effects of plasma treatment of the PDMS surface on lipid bilayer self-spreading behavior is investigated by confocal microscopy. The front-edge velocity of lipid bilayers increases with the plasma treatment time. By theoretical analyses with the extended-DLVO modeling, we find that the most likely cause of the velocity change is the hydration repulsion energy between the PDMS surface and lipid bilayers. Moreover, the growth behavior of membrane lobes on the underlying self-spreading lipid bilayer was affected by topography changes in the PDMS surface resulting from plasma treatment. Our findings suggest that the growth of self-spreading lipid bilayers can be controlled by changing the plasma treatment time.

Preparation of Size-controlled Giant Vesicles Under Physiological Conditions.

Giant vesicles (GVs) are model cell membranes that function as tools for the study of cell membrane properties. Recently, researchers have been calling for GVs of specific sizes for use in studies with precise needs. In this paper, we report a method of forming GVs of specific sizes by using an agarose-swelling approach. The resulting GVs had a narrow size distribution and were successfully formed under physiological conditions.

An initial exploration of hair cortisol responses to antidepressants in unmedicated patients with depression.

OBJECTIVE: Major depressive disorder is associated with abnormal functioning of the hypothalamic-pituitary-adrenal (HPA) axis. Studies using hair cortisol to measure the effect of antidepressants on the HPA axis are lacking. The aim of this study was to explore the long-term effects of antidepressants on hair cortisol concentration (HCC). METHODS: Participants were 42 patients and 36 healthy individuals. The patients took antidepressants for 4 weeks. Patient HCC was measured pre-treatment and post-treatment. The HCC of healthy controls was also measured. RESULTS: Patient post-treatment HCC (mean ± standard deviation: 34.40 ± 32.57 pmol/mg) was significantly higher than patient pre-treatment HCC (17.42 ± 12.40 pmol/mg) and healthy control HCC (10.22 ± 7.99 pmol/mg). No significant correlation was found between Hamilton Depression Rating Scale scores and HCC at pre-treatment or post-treatment. CONCLUSIONS: Hair cortisol concentration analysis could be used to monitor the dynamics of the effects of antidepressants on the HPA axis.

Sex differences in the clinical characteristics and brain gray matter volume alterations in unmedicated patients with major depressive disorder.

This study was to explore the sex differences in clinical characteristics and brain gray matter volume (GMV) alterations in 29 male patients with major depressive disorder (MDDm), 53 female patients with MDD (MDDf), and in 29 male and 53 female matched healthy controls. Maps of GMV were constructed using magnetic resonance imaging data and compared between groups. We evaluated clinical symptoms using the Hamilton Rating Scale for Depression and obtained a total score and five syndrome scores. A two-factor ANCOVA model was specified using SPM8, with sex and diagnosis as the between-subject factors. We found that: (1) significant GMV increase in the left cerebellum and GMV reduction in the bilateral middle temporal gyrus and left ventral medial prefrontal gyrus occurred selectively in male patients, while the GMV reduction in the left lingual gyrus and dorsal medial prefrontal gyrus occurred selectively in female patients; (2) MDDf may have experienced more severe sleep disturbance than MDDm; and (3) the severity of sleep symptom could be predicted by the sex specific brain structural alterations in depressions. These findings suggest that sex specific anatomical alterations existed in MDD, and these alterations were associated with the clinical symptoms.

Evaluation of tobacco use on Chinese population through ATTOC model: a cross-sectional survey on hospitalized psychiatric patients.

OBJECTIVES: To evaluate the feasibility of Addressing Tobaccos through Organizational Change (ATTOC) intervention to Chinese psychiatric patients, and to better address tobacco use through the ATTOC intervention model in the context of China. METHODS: The study was conducted in Mental Health Center of West China Hospital in 2010. A total of 100 hospitalized psychiatric patients were recruited to carry out ATTOC intervention. Subjects suffers from mental illness were diagnosed by professional psychiatrists according to the International Statistical Classification of Diseases (ICD-10) criteria. RESULTS: The prevalence of tobacco use in hospitalized psychiatric patients were closely correlated with the type of mental illness, family smoking history, sex, age, marital status, education status, etc. However, most psychiatric patients knew little about these, and tended to ignore the importance of smoking cessation. CONCLUSIONS: The ATTOC intervention program of the U.S. may be suitable for hospitalized Chinese psychiatric patients, and it could be applied for the tobacco smoking treatment in China. However, the health effects of tobacco use still did not draw amount attentions from both the clinicians and general public. It is urgently needed to raise people's awareness and carry out ATTOC intervention to control tobacco use, and ultimately terminate tobacco use.

3,4-methylenedioxyamphetamine upregulates p75 neurotrophin receptor protein expression in the rat brain.

The p75 neurotrophin receptor, which is a member of the tumor necrosis factor receptor superfamily, facilitates apoptosis during development and following central nervous system injury. Previous studies have shown that programmed cell death is likely involved in the neurotoxic effects of 3, 4-methylenedioxy-N-methylamphetamine (MDMA), because MDMA induces apoptosis of immortalized neurons through regulation of proteins belonging to the Bcl-2 family. In the present study, intraperitoneal injection of different doses of MDMA (20, 50, and 100 mg/kg) induced significant behavioral changes, such as increased excitability, increased activity, and irritability in rats. Moreover, changes exhibited dose-dependent adaptation. Following MDMA injection in rat brain tissue, the number of apoptotic cells dose-dependently increased and p75 neurotrophin receptor expression significantly increased in the prefrontal cortex, cerebellum, and hippocampus. These findings confirmed that MDMA induced neuronal apoptosis, and results suggested that this effect was related by upregulated protein expression of the p75 neurotrophin receptor.

Inhibition of Period1 gene attenuates the morphine-induced ERK-CREB activation in frontal cortex, hippocampus, and striatum in mice.

OBJECTIVE: Recent studies demonstrated that the Period1 gene (Per1) is involved in behavioral alterations induced by addictive drugs. We explored the effects of inhibiting expression in brain of Per1 on morphine conditioned place preference (CPP) and morphine-induced phosphorylation of extracellular signal-regulated kinase (ERK) and cAMP-response element binding protein (CREB) in mice. METHODS: During the first three sessions of conditioning, the male mice were intracerebroventricularlly (i.c.v.) injected with vehicle or deoxyribozyme 164 (DRz164) which cleaves per1 mRNA before subcutaneous (s.c.) injection morphine. The control group was given i.c.v. injection vehicle and s.c. injection saline instead of morphine. After testing CPP, mice were sacrificed and phosphorylated ERK and CREB in the frontal cortex, hippocampus, and striatum were examined by immunohistochemistry. RESULTS: Mice pretreated with DRz164 did not acquire morphine CPP. Pretreatment with DRz164 significant attenuated the morphine-induced activation of ERK and CREB in the frontal cortex, hippocampus, and striatum. CONCLUSIONS: Our results indicated that per1 plays an important role in morphine reward, and ERK-CREB pathway was involved in the effects of per1. We suggested that per1 gene may be a potential treatment target for drug addition.

[A preliminary study on the mechanism of neurotoxicity of MDMA--oxidative stress harm].

OBJECTIVE: Establishing a long-term neurotoxic model to explore the mechanism of neurotoxicity of 3,4-methylenedioxymethamphetamine (MDMA) and the putative protection conferred by Vit C against oxidative stress harm. METHODS: Male Wistar rats were randomly assigned to control group (A) and MDMA treatment groups(B, C, D, E). Rats of group B were given MDMA 20 mg/kg; groups C, D, E were given Vit C 250 mg/kg 30 min before administration of MDMA (Vit C 30 min group) and 3 h (Vit C 3 h group) and 5 h (VitC 5 h group) after administration of MDMA, respectively. Rats of control group were treated with the same volume of saline. Concentrations of ATP and ADP in brain cortex and 5-HT in hippocampus and occipital cortex were measured by high perfor-mance liquid chromatography; the expression of SERT mRNA was detected by in situ hybridization; and the expression of protein GFAP was detected by immunohisto-chemistry. RESULTS: hours after MDMA treatment, the concentration of ATP in brain cortex was lessened, compared with control (P <0.05). On the 7th day after MDMA treatment, the concentration of 5-HT in rat hippocampus and occipital cortex was decreased, compared with control (P<0.05). The expression of SERT mRNA in hippocampus was decreased, whereas the expression of GFAP in brain tissue was increased (P<0.05). The adminstration of Vit C 30 min before MDMA treatment and 3 h after MDMA treatment did not curb the decrease of ATP, 5-HT and the expression of SERT mRNA, but Vit C administrated 5 h after MDMA treatment could curb the decrease of ATP and the functional markers of 5-HT. And Vit C given at three time points did downregulate the GFAP expression. CONCLUSION: MDMA could deplete the direct energetic substance ATP. MDMA could exert neurotoxic effect on 5-HT system. Vit C given 5 h after MDMA administration could provide neuroprotection for ATP and 5-HT system.

[Long-term neurotoxic effects of MDMA result in cortical and hippocampal structural changes].

3,4-Methylenedioxymethamphetamine (MDMA) is a substituted amphetamine with stimulating and hallucinogenic properties. Since MDMA induces "ecstasy" it is extensively used as a "recreational" drug. It has been well established that MDMA is neurotoxic and can result in long-term degeneration of cerebral 5-hydroxytryptamine (5-HT) nerve terminals in many species. The present study was undertaken to investigate the long-term neurotoxic effects of MDMA on cortical and hippocampal structures, by repeatedly administering MDMA in short time. Male Wistar rats were randomly assigned to control group and MDMA-treated group. MDMA (10 mg/kg) was administered to rats of MDMA-treated group, once per hour, total 40 mg/kg; rats of control group were treated with the same volume of saline. Thirty-two weeks after administering MDMA, the expression of serotonin transporter (SERT) mRNA and diazepam binding inhibitor (DBI) mRNA was detected by in situ hybridization. The expression of glial fibrillary acidic protein (GFAP) was detected by immunohistochemistry, and the degeneration of nerve terminals was demonstrated by Bielschowsky and Glee Marsland silver staining. The results showed that the expression of SERT mRNA in hippocampus decreased by 31.96%, while expression of DBI mRNA in neocortex increased by 40.51%, compared with the control group (P<0.05). The expression of GFAP in the brain tissue increased (P<0.05), while significant reduction of the nerve terminals in neocortex was demonstrated by silver staining, compared with the control group. These results suggest that the neurotoxicity of MDMA results in sustained cortical and hippocampal structural changes, which in turn result in disorder of the brain functions.