Membralin deficiency dysregulates astrocytic glutamate homeostasis leading to ALS-like impairment.

Mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) are yet unclear. Specific deletion of the ER-component membralin in astrocytes manifested postnatal motor defects and lethality in mice, causing the accumulation of extracellular glutamate through reducing the glutamate transporter EAAT2. Restoring EAAT2 levels in membralin KO astrocytes limited astrocyte-dependent excitotoxicity in motor neurons. Transcriptomic profiles from mouse astrocytic membralin KO motor cortex indicated significant perturbation in KEGG pathway components related to ALS, including downregulation of Eaat2 and upregulation of Tnfrsf1a. Changes in gene expression with membralin deletion also overlapped with mouse ALS models and reactive astrocytes. Our results shown that activation of TNF receptor (TNFR1)-NFκB pathway known to suppress Eaat2 transcription was upregulated with membralin deletion. Further, reduced membralin and EAAT2 levels correlated with disease progression in spinal cord from SOD1-mutant mouse models, and reductions in membralin/EAAT2 were observed in human ALS spinal cord. Importantly, overexpression of membralin in SOD1G93A astrocytes decreased TNFR1 levels and increased EAAT2 expression, and improved motor neuron survival. Importantly, upregulation of membralin in SOD1G93A mice significantly prolonged mouse survival. Together, our study provided a mechanism for ALS pathogenesis where membralin limited glutamatergic neurotoxicity, suggesting that modulating membralin had potentials in ALS therapy.

Inhibitory effects of Dendrobium alkaloids on memory impairment induced by lipopolysaccharide in rats.

Dendrobium alkaloids (DNLA), extracted from Dendrobium nobile Lindl. whose botanical name is Dendrobium moniliforme, Orchidaceae family, were studied for their effect on lipopolysaccharide (LPS)-induced memory impairment in rats. SD rats were pretreated with DNLA (40, 80, 160 mg/kg/d for 7 d), followed by LPS (50 µg) injection into the right lateral ventricle to produce memory impairment. DNLA treatment continued for another 13 days. The spatial behavior was tested by the Morris water maze; the level of tumor necrosis factor receptor 1 (TNFR1) mRNA was detected by real time RT-PCR, and the protein level of TNFR1, nuclear factor kappa-B (NF- κB) and phosphorylated p38 mitogen-activated protein kinases (p-p38 MAPK) by Western blotting. The results showed that DNLA significantly improved the neurobehavioral performance and prevented LPS-induced elevation in TNFR1 mRNA and protein levels. LPS-induced activation of p38 MAPK and NF- κB pathway was also suppressed. In conclusion, DNLA is effective in protecting against LPS-induced brain impairment, and this effect is due, at least in part, to prevent overexpression of TNFR1 via inhibition of p-p38 MAPK and the downstream NF- κB signal pathway.

α-melanocyte-stimulating hormone modulates lipopolysaccharide plus interferon-γ-induced tumor necrosis factor-α expression but not tumor necrosis factor-α receptor expression in cultured hypothalamic neurons.

In a previous work we showed that the melanocortin alpha-melanocyte-stimulating hormone (α-MSH) exerts anti-inflammatory action through melanocortin 4 receptor (MC4R) in vivo in rat hypothalamus. In this work, we examined the effect of α-MSH on the expression of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) and their receptors in primary cultured rat hypothalamic neurons. We also investigated α-MSH's possible mechanism/s of action. α-MSH (5 µM) decreased TNF-α expression induced by 24h administration of a combination of bacterial lipopolysaccharide (LPS, 1 µg/ml) plus interferon-γ (IFN-γ, 50 ng/ml). Expression of TNF-α and IL-1ß receptors TNFR1, TNFR2 and IL-1RI, was up-regulated by LPS+IFN-γ whereas α-MSH did not modify basal or LPS+IFN-γ-induced-TNFRs or IL-1RI expression. Both α-MSH and LPS+IFN-γ treatments increased CREB activation. α-MSH did not modify NF-κB activation induced by LPS+IFN-γ in hypothalamic neurons. In conclusion, our data show that α-MSH reduces TNF-α expression in hypothalamic neurons by a mechanism which could be mediated by CREB. The regulation of inflammatory processes in the hypothalamus by α-MSH might help to prevent neurodegeneration resulting from inflammation.

[Comparative study of that synergistic effect of cisplatin combined with compound herbal medicinal prescription for tonic quality and activating blood circulation is on SKOV3 cell proliferation and apoptosis].

OBJECTIVE: To investigate the synergistic effects on cell apoptosis and growing restriction of SKOV3 cells by the combination of compound herbal medicinal prescription (CHMP) with cisplatin (DDP). METHODS: Cisplatin and two CHMP for tonic quality(CHMP1) and activating blood circulation (CHMP2), which was medicated serum, were prepared and used to treat the human ovarian carcinoma cell line SKOV3. By serum pharmacologic method, the growth and apoptosis of SKOV3 cell were observed at different time points(24,48,72, 96 h) with different concentrations of medicated serum. Coefficient of drug interaction (CDI) between CHMP, and CHMP2 was studied by MTT method. The effects of control group(A group),CHMP1 group(B group),CHMP2 group (C group), DDP group(D group), CHMP1 + DDP group(E group), CHMP2 + DDP group(Fgroup)to SKOV3 cell were studied by flow cytometry; and the cell apoptosis was observed by agarose electrophoresis; the expressions of TNFR1, caspase-8 on each group were analyzed by Western blot method. RESULTS: Synergistic effects were found between herbal medicinal mixtures and DDP, Restraining rate of SKOV3 and CHMP serum concentration was not in a dose-dependent manner as DDP was. CDI between CHMPI and CHMPS was found to be significant difference (CDI of CHMP1, CHMP2 and DDPwas 0.66, 0.58 respectively). It showed that the combined treatment was able to get better effect than single drug treatment. The performed agarose electrophoresis revealed the extracted DNA to show a typical ladder patterns for cell apoptosis. The analysis results of western blot showed the increased expressions of TNFR1 and caspase-8 after combined using of medicine, which were accord to the rates of apoptosis. CONCLUSIONS: CHMP drug granules show the synergistic effects with DDP, and the suppressing functions in the course of cell proliferation, and the inducing effect on apoptosis of human ovarian carcinoma cell line SKOV3 in vitro. And this mechanism is showed to be sponsored by the activation of TNFR1 and Caspase-8.

[Production of soluble form of human TNF-alpha ligand-binding domain type 1 receptor by expression in Drosophila cells].

5His-tagged human TNFalpha type I receptor (TNFR1) ligand-binding domain was produced in Drosophila cells under control of metallothionein Cu-inducible promoter and purified by Ni-NTA affinity chromatography to homogeneity. TNFR1 gene fragment was cloned by PCR from CD8+ in vitro cultured T-killer normal linage cDNA. In despite of three disulfide bonds, the recombinant protein was correctly folded which was conformed by TNFalpha ligand binding assay in ELISA variant.

The differential contribution of tumour necrosis factor to thermal and mechanical hyperalgesia during chronic inflammation.

Therapies directed against tumour necrosis factor (TNF) are effective for the treatment of rheumatoid arthritis and reduce pain scores in this condition. In this study, we sought to explore mechanisms by which TNF contributes to inflammatory pain in an experimental model of arthritis. The effects of an anti-TNF agent, etanercept, on behavioural pain responses arising from rat monoarthritis induced by complete Freund's adjuvant were assessed and compared with expression of TNF receptors (TNFRs) by dorsal root ganglion (DRG) cells at corresponding time points. Etanercept had no effect on evoked pain responses in normal animals but exerted a differential effect on the thermal and mechanical hyperalgesia associated with rat arthritis induced by complete Freund's adjuvant (CFA). Joint inflammation was associated with increased TNFR1 and TNFR2 expression on DRG cells, which was maintained throughout the time course of the model. TNFR1 expression was increased in neuronal cells of the DRG bilaterally after arthritis induction. In contrast, TNFR2 expression occurred exclusively on non-neuronal cells of the macrophage-monocyte lineage, with cell numbers increasing in a TNF-dependent fashion during CFA-induced arthritis. A strong correlation was observed between numbers of macrophages and the development of mechanical hyperalgesia in CFA-induced arthritis. These results highlight the potential for TNF to play a vital role in inflammatory hyperalgesia, both by a direct action on neurons via TNFR1 and by facilitating the accumulation of macrophages in the DRG via a TNFR2-mediated pathway.