Munc18-1 Contributes to Hippocampal Injury in Septic Rats Through Regulation of Syntanxin1A and Synaptophysin and Glutamate Levels.

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction closely associated with mortality in the acute phase of sepsis. Abnormal neurotransmitters release, such as glutamate, plays a crucial role in the pathological mechanism of SAE. Munc18-1 is a key protein regulating neurotransmission. However, whether Munc18-1 plays a role in SAE by regulating glutamate transmission is still unclear. In this study, a septic rat model was established by the cecal ligation and perforation. We found an increase in the content of glutamate in the hippocampus of septic rat, the number of synaptic vesicles in the synaptic active area and the expression of the glutamate receptor NMDAR1. Meanwhile, it was found that the expressions of Munc18-1, Syntaxin1A and Synaptophysin increased, which are involved in neurotransmission. The expression levels of Syntaxin1A and Synaptophysin in hippocampus of septic rats decreased after interference using Munc18-1siRNA. We observed a decrease in the content of glutamate in the hippocampus of septic rats, the number of synaptic vesicles in the synaptic activity area and the expression of NMDAR1. Interestingly, it was also found that the down-regulation of Munc18-1 improved the vital signs of septic rats. This study shows that CLP induced the increased levels of glutamate in rat hippocampus, and Munc18-1 may participate in the process of hippocampal injury in septic rats by affecting the levels of glutamate via regulating Syntaxin1A and Synaptophysin. Munc18-1 may serve as a potential target for SAE therapy.

Modeling rapid and selective capture of nNOS-PSD-95 uncouplers from Sanhuang Xiexin decoction by novel molecularly imprinted polymers based on metal-organic frameworks.

Novel and highly selective molecularly imprinted polymers based on the surface of metal-organic frameworks, NH2-MIL-101(Cr) (MIL@MIPS), were successfully fabricated to capture neuronal nitric oxide synthase-postsynaptic density protein-95 (nNOS-PSD-95) uncouplers from Sanhuang Xiexin Decoction (SXD) for stroke treatment. The resultant polymers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction. The performance tests revealed that MIL@MIPs had a large binding capacity, fast kinetics, and excellent selectivity. Then the obtained polymers were satisfactorily applied to solid-phase extraction coupled with high-performance liquid chromatography to selectively capture nNOS-PSD-95 uncouplers from SXD. Furthermore, the biological activities of components obtained from SXD were evaluated in vivo and in vitro. As a consequence, the components showed a potent neuroprotective effect from the MTS assay and uncoupling activity from the co-immunoprecipitation experiment. In addition, the anti-ischemic stroke assay in vivo was further investigated to determine the effect of reducing infarct size and ameliorating neurological deficit by the active components. Therefore, this present study contributes a valuable new method and new tendency to selectively capture active components for stroke treatment from SXD and other natural medicines.

A biomimetic fluorescent nanosensor based on imprinted polymers modified with carbon dots for sensitive detection of alpha-fetoprotein in clinical samples.

A biomimetic fluorescent nanosensor based on molecularly imprinted polymers modified with carbon dots (CDs@MIPs) has been prepared for rapid, selective and sensitive detection of alpha-fetoprotein (AFP) in clinical samples. The nanosensor was produced using vinyl-functionalized CDs (V-CDs) as transducer elements and support materials, AFP as the template protein, N-isopropylacrylamide (NIPAM) and 4-vinylphenylbronic acid (VPBA) as the thermo-responsive and pH-responsive monomer, respectively, and ammonium peroxodisulphate (APS) and N,N'-methylene bisacrylamide (MBA) as the initiator and cross-linker, respectively. The newly synthesized nanosensor was characterized by FT-IR, TEM, XRD and elemental analysis, which unambiguously confirmed the successful formation of the nanosensor. The fluorescence quenching degree of CDs@MIPs exhibited a good linear response to AFP in a concentration range of 10 to 100 ng mL-1, the limit of detection (LOD) of 0.474 ng mL-1, and high recoveries at three spiking levels of AFP ranging from 97.05% to 102.00%, with relative standard deviations (RSDs) below 4.2% being obtained. Moreover, the proposed CDs@MIPs were successfully exploited to detect AFP in human serum samples. This study successfully established a novel method for rapid, convenient, and highly sensitive and selective detection of AFP, which provides new ideas for the detection of tumor markers.

[Efficient discovery and capturing of nNOS-PSD-95 uncouplers from Trifolium pratense].

Magnetic molecularly imprinted polymers(MMIPs) were prepared with ZL006 as template, acrylamide(AA) as the functional monomer, and acetonitrile as pore-forming agent; then Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM) were used to characterize their forms and structures. Simultaneously, the MMIPs prepared previously were used as sorbents for dispersive magnetic solid phase extraction(DSPE) to capture and identify potential nNOS-PSD-95 uncouplers from extracts of Trifolium pratense and the the activities of the screened compounds were evaluated by the neuroprotective effect and co-immunoprecipitation test. The experiment revealed that the successfully synthesized MMIPs showed good dispersiveness, suitable particle size and good adsorption properties. Formononetin, prunetin and biochanin A were separated and enriched from Trifolium pratense by using the MMIPs as artificial antibodies and finally biochanin A was found to have higher cytoprotective action and uncoupling action according to the neuroprotective effect and co-immunoprecipitation test.

[Expression of mitochondrial ferritin in K562 leukemic cell during ATRA-induced cell differentiation].

OBJECTIVE: To investigate the expression of MtF, transferrin receptor 1 (TfR1) and ferritin (Fn) mRNAs in K562 leukemic cells during ATRA-induced cell differentiation and to explore the interrelationship between the expression levels of these iron metabolism-related molecules. METHODS: K562 cells cultured with or without ATRA (1 micromol/L) were collected at 24, 72 and 120 hours respectively. Cell differentiation toward granulocyte lineage was confirmed by microscopic study (Wright's staining) and flowcytometry. Expression levels of MtF, TfR1 and Fn were evaluated with semiquantitative RT-PCR, while K562 cells cultured without ATRA as control. RESULTS: Over 21.2% of K562 cells demonstrated features of granulocyte, and the expression of CD13 on cell surface increased significantly at day 5 with ATRA treatment (P < 0.05, compared with control). K562 cells could express a certain level of MtF before ATRA-induced differentiation. With increase of ATRA-induced cell differentiation, MtF mRNA expressions were downregulated progressively. After 5 days of induced cell differentiation, expression levels of MtF and TfR1 mRNA were just 86.5% and 79.2% of that before ATRA treatment. While Fn mRNA expression increased to 1.21 folds of that before ATRA treatment. CONCLUSION: MtF expression is downregulated during ATRA-induced K562 cell differentiation, with concomitant downregulation of TfR1 and upregulation of Fn. The coordinated expression regulation of these key iron metabolism-related molecules during cell differentiation may in turn inhibit TfR1-mediated iron uptake via endocytosis and thus adversely affect cell proliferation potential.