Fas-associated death domain protein (FADD)/mediator of receptor-induced toxicity-1 is required for signaling induced by death receptors such as Fas. In earlier studies, FADD-deficient mice died in utero, and a FADD deficiency in embryonic stem cells inhibited T cell production in viable FADD−/−→RAG-1−/− chimeras. To analyze the temporal requirement of FADD in the development and function in the T lineage, it is necessary to establish viable mutant mice producing detectable FADD-deficient T cells. We generated mice that express a functional FADD:GFP fusion gene reconstituting normal embryogenesis and lymphopoiesis in the absence of the endogenous FADD. Efficient T cell-specific deletion of FADD:GFP was achieved, as indicated by the presence of a high percentage of GFP-negative thymocytes and peripheral T cells in mice expressing Lck-Cre or CD4-Cre. Sorted GFP-negative thymocytes and peripheral T cells contained undetectable levels of FADD and were resistant to apoptosis induced by Fas, TNF, and TCR restimulation. These T cell-specific FADD-deficient mice contain normal thymocyte numbers, but fewer peripheral T cells. Purified peripheral FADD-deficient T cells failed to undergo extensive homeostatic expansion after adoptive transfer into lymphocyte-deficient hosts, and responded poorly to proliferation induced by ex vivo TCR stimulation. Furthermore, deletion of FADD in preactivated mature T cells using retrovirus-Cre resulted in no proliferation. These results demonstrate that FADD plays a dispensable role during thymocyte development, but is essential in maintaining peripheral T cell homeostasis and regulating both apoptotic and proliferation signals.

Single molecule confocal microspectroscopic methods are used to characterize individual molecular-scale environments in silicate thin films for the first time. Rhodamine dyes doped into the materials at nanomolar levels are used as probes of the physicochemical environment in which each molecule is entrapped. The results are compared to those obtained from dye-doped organic polymer films. Static fluorescence spectra and time-dependent fluorescence signals recorded for a large number of single molecules show the silicate materials to be highly inhomogeneous in comparison to the polymer films. Histograms of the fluorescence maxima for encapsulated Rhodamine B show a full width at half-maximum of 13.3 nm for the silicate host framework and 6.7 nm for the polymer film. The integrated fluorescence signal from single molecules, recorded with millisecond time resolution, under continuous illumination conditions, is also sensitive to the local environment. The time-dependent signal traces show dramatic intensity fluctuations for some molecules and none for others. The fluctuations occur most frequently for the silicate-entrapped dye. In the present work, the signal fluctuations are proposed to result from time-dependent variations in the molecular environment, which in turn cause changes in the excitation and emission characteristics of the molecules. The photophysical phenomena behind these fluctuations include quantum yield variations, intersystem crossing to a long-lived dark state, and, to a lesser extent, spectral diffusion. All such effects are highly dependent upon the physicochemical properties of the molecular-scale environment, as shown by comparison to results obtained for the polymer samples. The results are used as further evidence for the heterogeneous nature of entrapment in silicate host structures. The dynamic nature of many of the molecular-scale environments in these materials is demonstrated as well.

BackgroundShwachman-Diamond syndrome is an inherited multisystem disorder characterized by bone marrow and pancreatic dysfunction as well as metaphyseal dysostosis. Ninety percent of the patients have mutations in the Shwachman-Bodian-Diamond syndrome gene (SBDS). The relationship between SBDS and cell survival is unknown. In this study we investigated whether deficiency of the SBDS protein can cause increased apoptosis and, if so, what pathways are involved in this process.

It is possible to accurately image and measure the cross-sectional structures of the bulbar conjunctival tissue with high resolution OCT.

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Aim: To investigate the effects of the selective serotonin reuptake inhibitor (SSRI) fluoxetine on extracellular matrix (ECM) remodeling of the pulmonary artery and inflammation of the lungs in pulmonary arterial hypertension (PAH) induced by monocrotaline in rats. Methods: MCT-induced chronic PAH was established in Wistar rats. After treatment with fluoxetine for 3 weeks, pulmonary hemodynamic measurement and morphological investigation of lung tissues were undertaken. The main components of the ECM, elastin and collagen, were detected using Van Gieson stain and Orcein stain, respectively, or using Victoria-ponceau's double stain. The ECM proteolytic enzymes matrix metalloproteinase (MMP)-2 and MMP-9, and the tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2, were detected by Western blot. Inflammation of lung tissue was assayed using lung morphology and inflammatory cytokine expression. Results: Fluoxetine (2 and 10 mg/kg) significantly inhibited MCT-induced PAH, attenuated pulmonary arterial muscularization and ECM remodeling, and decreased MMP/TIMP expression. Fluoxetine also suppressed inflammatory responses in lung tissue and inhibited the expression of the inflammatory cytokines interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). Conclusion: Fluoxetine inhibited MCT-induced ECM remodeling of the pulmonary artery and inflammation of lung tissue. These effects were related to its inhibition on MMPs/TIMPs and cytokine productions.Keywords: extracellular matrix; inflammation; pulmonary arterial hypertension; selective serotonin reuptake inhibitor Acta Pharmacologica Sinica (2011) 32: 217-222; doi: 10.1038/aps.2010 published online 10 Jan 2011 Original Article * To whom correspondence should be addressed. [11,12] . It was reported that the plasma concentration in serotonin was significantly increased in PAH patients [13] . We have previously reported that serotonin induced PASMCs mitogenesis in vitro, and serotonin selective reuptake inhibitor (SSRI) fluoxetine inhibited serotonininduced PASMCs proliferation via blocking SERT [14] . We have also found that SSRI fluoxetine and sertraline protected against pulmonary vascular remodeling by inhibiting pulmonary vascular muscularization in monocrotaline (MCT)-induced pulmonary hypertensive rats [15,16] . However, whether SSRI has a protective effect against ECM remodeling in the pulmonary artery remains unknown.Inflammatory mechanisms play an important role in the development of PAH. It has been demonstrated that lymphocytes and macrophages were present in the vicinity of remodeled pulmonary vessels and that cytokines such as interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) were increased in PAH patients [17][18][19][20] . We have also reported previously that chronic lung inflammation existed in MCT-induced PAH rats [21] . However, several studies have shown that...

Shwachman-Diamond syndrome (SDS) is an inherited disorder characterized by reduced cellularity in the bone marrow and exocrine pancreas. Most patients have mutations in the SBDS gene, whose functions are unknown. We previously showed that cells deficient in the SBDS protein are characterized by accelerated apoptosis and Fas hypersensitivity, suggesting that the protein might play an important role in Fas-mediated apoptosis. To study the mechanism of Fas hypersensitivity, we compared shRNA-mediated SBDS-knockdown HeLa cells and SDS marrow CD34+ cells for their sensitivity to several groups of apoptosis inducers. Marked hypersensitivity was noticed in response to Fas stimulation, but not to tumor necrosis factor-alpha, DNA-damaging agents, transcription inhibition or protein synthesis inhibition. To identify the Fas signaling factors that cause hypersensitivity, we analyzed the expression of the pathway's proteins. We found that Fas accumulated at the plasma membrane in SBDS-knockdown cells with corresponding expression of Fas transcript 1, the main Fas transcript which contains both the transmembrane domain and the death domain. However, the total levels of Fas protein and mRNA were comparable to controls, and Fas internalization occurred normally. Expression of FADD, caspase-8 and -3 were not elevated and the pathway inhibitors: ERK, c-FLIP and XIAP were not decreased. These results suggest that SBDS loss results in abnormal accumulation of Fas at the plasma membrane, where it sensitizes the cells to stimulation by Fas ligand.

Aim: To investigate whether atorvastatin treatment could prevent Aβ 1-42 oligomer (AβO)-induced synaptotoxicity and memory dysfunction in rats, and to elucidate the mechanisms involved in the neuroprotective actions of atorvastatin. Methods: SD rats were injected with AβOs (5 nmol, icv). The rats were administrated with atorvastatin (10 mg·kg -1 ·d -1 , po) for 2 consecutive weeks (the first dose was given 5 d before AβOs injection). The memory impairments were evaluated with Morris water maze task. The expression of inflammatory cytokines in the hippocampus was determined using ELISA assays. The levels of PSD-95 and p38MAPK proteins in rat hippocampus were evaluated using Western blot analysis. For in vitro experiments, cultured rat hippocampal neurons were treated with AβOs (50 nmol/L) for 48 h. The expression of MAP-2 and synaptophysin in the neurons was detected with immunofluorescence. Results: The AβO-treated rats displayed severe memory impairments in Morris water maze tests, and markedly reduced levels of synaptic proteins synaptophysin and PSD-95, increased levels of inflammatory cytokines (IL-1β, IL-6 and TNF-α) and p38MAPK activation in the hippocampus. All these effects were prevented or substantially attenuated by atorvastatin administration. Pretreatment of cultured hippocampal neurons with atorvastatin (1 and 5 µmol/L) concentration-dependently attenuated the AβO-induced synaptotoxicity, including the loss of dendritic marker MAP-2, and synaptic proteins synaptophysin and PSD-95. Pretreatment of the cultured hippocampal neurons with the p38MAPK inhibitor SB203580 (5 µmol/L) blocked the AβO-induced loss of synaptophysin and PSD-95. Conclusion: Atorvastatin prevents AβO-induced synaptotoxicity and memory dysfunction through a p38MAPK-dependent pathway.