The isotopic composition of different materials can be imaged by secondary ion mass spectrometry. In biology, this method is mainly used to study cellular metabolism and turnover, by pulsing the cells with marker molecules such as amino acids labelled with stable isotopes ((15)N, (13)C). The incorporation of the markers is then imaged with a lateral resolution that can surpass 100 nm. However, secondary ion mass spectrometry cannot identify specific subcellular structures like organelles, and needs to be correlated with a second technique, such as fluorescence imaging. Here, we present a method based on stimulated emission depletion microscopy that provides correlated optical and isotopic nanoscopy (COIN) images. We use this approach to study the protein turnover in different organelles from cultured hippocampal neurons. Correlated optical and isotopic nanoscopy can be applied to a variety of biological samples, and should therefore enable the investigation of the isotopic composition of many organelles and subcellular structures.
Clinical outcome of patients suffering from head neck squamous cell carcinomas is still poor due to recurrent disease and surgical limitations. There is still a demand for multimodality approaches and new therapeutic options. Hypericin is a promising phototoxic drug which was investigated for its effects on head neck squamous cell carcinoma cells in vitro. FaDu cells incubated with or without hypericin were illuminated (450-700 nm, 50,000 lx) for different time periods. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide- and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay were used to score metabolic and apoptotic activity. Even after the shortest illumination FaDu cells incubated with hypericin showed massive reduction of metabolism and excessive apoptosis. This was present even with the lowest hypericin concentration. Cells without hypericin or without illumination were not affected. These photosensitizing effects of hypericin could be suitable for clinical application and could lead to the development of an intraoperative photodynamic therapy of head neck squamous cell carcinomas.
Activation of the nuclear transcription factor ?B (NF-?B) regulates the expression of inflammatory genes crucially involved in the pathogenesis of inflammatory diseases. NF-?B governs the expression of adhesion molecules that play a pivotal role in leukocyte-endothelium interactions. We uncovered the crucial role of NF-?B activation within endothelial cells in models of immune-mediated diseases using a "sneaking ligand construct" (SLC) selectively inhibiting NF-?B in the activated endothelium. The recombinant SLC1 consists of three modules: (i) an E-selectin targeting domain, (ii) a Pseudomonas exotoxin A translocation domain, and (iii) a NF-?B Essential Modifier-binding effector domain interfering with NF-?B activation. The E-selectin-specific SLC1 inhibited NF-?B by interfering with endothelial I?B kinase 2 activity in vitro and in vivo. In murine experimental peritonitis, the application of SLC1 drastically reduced the extravasation of inflammatory cells. Furthermore, SLC1 treatment significantly ameliorated the disease course in murine models of rheumatoid arthritis. Our data establish that endothelial NF-?B activation is critically involved in the pathogenesis of arthritis and can be selectively inhibited in a cell type- and activation stage-dependent manner by the SLC approach. Moreover, our strategy is applicable to delineating other pathogenic signaling pathways in a cell type-specific manner and enables selective targeting of distinct cell populations to improve effectiveness and risk-benefit ratios of therapeutic interventions.
Previous studies indicate that the release of proteases, including the gelatinase matrix metalloproteinase (MMP)-9, from mature granulocytes plays a crucial role in cytokine-induced hematopoietic stem and progenitor cell (HSPC) mobilization. However, studies with MMP-9-deficient mice revealed that HSPC mobilization was normal in these animals, suggesting that additional proteases must be active at clinically relevant cytokine concentrations. In the present study, we provide evidence that the collagenase MMP-8 is involved in stem cell mobilization. A rapid release of MMP-8 from isolated neutrophil granulocytes can be observed during an in vitro culture. During granulocyte colony-stimulating factor-induced HSPC mobilization, highly elevated serum concentrations of MMP-8 were observed on days 4 to 6 of the mobilization regimen, concomitantly with elevated MMP-9 serum levels and higher numbers of circulating CD34(+) cells. Elevated serum concentrations of both proteases were also found in umbilical cord blood serum. In functional assays, adhesion of HSPC to osteoblasts as an essential component of the endosteal stem cell niche is negatively influenced by MMP-8. The chemokine CXCL12, which is critically involved in stem cell trafficking, can be proteolytically processed by MMP-8 treatment. This degradation has a strong inhibitory influence on HSPC migration. Taken together, our data strongly suggest that MMP-8 can be directly involved in hematopoietic stem cell mobilization and trafficking.
Telethonin (also known as titin-cap or t-cap) is a 19-kDa Z-disk protein with a unique ?-sheet structure, hypothesized to assemble in a palindromic way with the N-terminal portion of titin and to constitute a signalosome participating in the process of cardiomechanosensing. In addition, a variety of telethonin mutations are associated with the development of several different diseases; however, little is known about the underlying molecular mechanisms and telethonins in vivo function.
20-hydroxyecdysone has numerous favorable effects on a variety of organs, including the skin, where it improves wound healing. It is devoid of estrogenic and androgenic effects. Therefore, application of 20-hydroxyecdysone might be a new approach to improve skin conditions in postmenopausal women, and this was investigated in ovariectomized (OVX) rats.
Macrophages play a central role in host defense against mycobacterial infection and anti- TNF therapy is associated with granuloma disorganization and reactivation of tuberculosis in humans. Here, we provide evidence for the presence of a T cell receptor (TCR) ?? based recombinatorial immune receptor in subpopulations of human and mouse monocytes and macrophages. In vitro, we find that the macrophage-TCR?? induces the release of CCL2 and modulates phagocytosis. TNF blockade suppresses macrophage-TCR?? expression. Infection of macrophages from healthy individuals with mycobacteria triggers formation of clusters that express restricted TCR V? repertoires. In vivo, TCR?? bearing macrophages abundantly accumulate at the inner host-pathogen contact zone of caseous granulomas from patients with lung tuberculosis. In chimeric mouse models, deletion of the variable macrophage-TCR?? or TNF is associated with structurally compromised granulomas of pulmonary tuberculosis even in the presence of intact T cells. These results uncover a TNF-regulated recombinatorial immune receptor in monocytes/macrophages and demonstrate its implication in granuloma formation in tuberculosis.
Sepsis is characterized by systemic microvascular dysfunction. Endothelial progenitor cells (EPCs) are critically involved in maintaining vascular homeostasis under both physiological and pathological conditions. The aim of the present study was to analyze the endothelial progenitor cell system in patients suffering from sepsis with acute renal dysfunction.
Aim: Orthotopic models utilizing orthotopic implantation have been used for developing cancer models of multiple tumor entities. The aim of this study was to evaluate the role of orthotopic injection in establishing a model of esophageal cancer using a human green fluorescent protein (GFP) cell line of human esophageal carcinoma.
This review focuses on technical advances in fluorescence microscopy techniques including laser scanning techniques, fluorescence-resonance energy transfer (FRET) microscopy, fluorescence lifetime imaging (FLIM), stimulated emission depletion (STED)-based super-resolution microscopy, scanning confocal endomicroscopes, thin-sheet laser imaging microscopy (TSLIM), and tomographic techniques such as early photon tomography (EPT) as well as on clinical laser-based endoscopic and microscopic techniques. We will also discuss the new developments in the field of fluorescent dyes and fluorescent genetic reporters that enable new possibilities in high-resolution and molecular imaging both in in vitro and in vivo. Small animal and tissue imaging benefit from the development of new fluorescent proteins, dyes, and sensing constructs that operate in the far red and near-infrared spectrum.
In Wegeners granulomatosis (WG), vasculitic lesions are characterized by prominent infiltration of polymorphonuclear neutrophils (PMN) and T cells, but underlying pathogenic mechanisms remain to be defined. We analyzed the expression and functional role of the C-class chemokine lymphotactin, XCL1, in WG.
Endothelial progenitor cells (EPCs) have been shown to promote neovascularization under physiologic and pathologic conditions. Statins have been documented to increase the total number of circulating EPCs in long-term treated patients. Lipid apheresis is used to treat patient with refractory hyperlipidemia. The aim of our study was to evaluate whether lipid apheresis is associated with EPC mobilization.
The sentinel and immune functions of microglia require rapid and appropriate reactions to infection and damage. Their Toll-like receptors (TLRs) sense both as threats. However, whether activated microglia mount uniform responses or whether subsets conduct selective tasks is unknown. We demonstrate that murine microglia reorganize their responses to TLR activations postnatally and that this process comes with a maturation of TLR4-organized functions. Although induction of MHCI for antigen presentation remains as a pan-populational feature, synthesis of TNF? becomes restricted to a subset, even within adult central nervous system regions. Response heterogeneity is evident ex vivo, in situ, and in vivo, but is not limited to TNF? production or to TLR-triggered functions. Also, clearance activities for myelin under physiological and pathophysiological conditions, IFN?-enforced upregulation of MHCII, or challenged inductions of other proinflammatory factors reveal dissimilar microglial contributions. Notably, response heterogeneity is also confirmed in human brain tissue. Our findings suggest that microglia divide by constitutive and inducible capacities. Privileged production of inflammatory mediators assigns a master control to subsets. Sequestration of clearance of endogenous material versus antigen presentation in exclusive compartments can separate potentially interfering functions. Finally, subsets rather than a uniform population of microglia may assemble the reactive phenotypes in responses during infection, injury, and rebuilding, warranting consideration in experimental manipulation and therapeutic strategies.
Background. Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) are autoimmune-mediated diseases characterized by vasculitic inflammation of respiratory tract and kidneys. Clinical observations indicated a strong association between disease activity and serum levels of certain types of autoantibodies (antineutrophil cytoplasm antibodies with cytoplasmic [cANCA in GPA] or perinuclear [pAN CA in MPA] immunofluorescence). Pathologically, both diseases are characterized by severe microvascular endothelial cell damage. Early endothelial outgrowth cells (eEOCs) have been shown to be critically involved in neovascularization under both physiological and pathological condition. Objectives. The principal aims of our study were (i) to analyze the regenerative activity of the eEOC system and (ii) to determine mPR3 and MPO expression in myelo monocytic cells with endothelial characteristics in GPA and MPA patients. Methods. In 27 GPA and 10 MPA patients, regenerative activity blood-derived eEOCs were analyzed using a culture-forming assay. Flk-1(+), CD133(+)/Flk-1(+), mPR3(+), and Flk-1(+)/mPR3(+) myelomonocytic cells were quantified by FACS analysis. Serum levels of Angiopoietin-1 and TNF-? were measured by ELISA. Results. We found reduced eEOC regeneration, accompanied by lower serum levels of Angiopoietin-1 in GPA patients as compared to healthy controls. In addition, the total numbers of Flk-1(+) myelomonocytic cells in the peripheral circulation were decreased. Membrane PR3 expression was significantly higher in total as well as in Flk-1(+) myelomonocytic cells. Expression of MPO was not different between the groups. Conclusions. These data suggest impairment of the eEOC system and a possible role for PR3 in this process in patients suffering from GPA.
Elderly people often develop visceral obesity accompanied by osteoporosis. Visceral adipocytes secrete a number of adipokines and cytokines which augment the development of arteriosclerosis and type 2 diabetes. Bone marrow fat cells also secrete these pro-inflammatory cytokines which stimulate osteoclast and inhibit osteoblast activity. Ovariectomized (ovx) rats also develop general and bone marrow obesity and osteoporosis both of which can be partially prevented by estradiol (E2) and the special extract of Cimicifuga racemosa (CR) BNO 1055. Whether this extract or the thereof isolated triterpene-saponins or polar substances can also prevent bone marrow obesity and thereby the development of osteoporosis was compared with the effects of estradiol (E2).
An unphysiologic accumulation of fat cells in many parts of the body including abdomen and joints results in increased production of pro-inflammatory cytokines which have adverse effects on serum lipids, glucose and on joint cartilage. The special extract of Cimicifuga racemosa CR BNO 1055 was shown to reduce the size of the abdominal fat depot. It was therefore tempting to test whether this extract, its saponin and its unpolar and polar fractions S- and R-fraction respectively (no quotation) also reduce fat depots and fat cell accumulation in a fat depot located in the lower hind leg (called paratibial fat depot = PFD), in joint fat pads (in the knee joint this is called Hoffas fat pad) that occur in response to ovariectomy and whether this was accompanied by reduced serum lipids, glucose and improved cartilage features in the knee joint.
Proper illumination is essential for light microscopy. Whereas in early years incandescent light was the only illumination, today, more and more specialized light sources, such as lasers or arc lamps are used. Because of the high efficiency and brightness that light-emitting diodes (LED) have reached today, they have become a serious alternative for almost all kinds of illumination in light microscopy. LED have a high durability, do not need expensive electronics, and they can be switched in nanoseconds. Besides this, they are available throughout the UV/Vis/NIR-spectrum with a narrow bandwidth. This makes them ideal light sources for fluorescence microscopy. The white LED, with a color temperature ranging from 2,600 up to 5,000 K is an excellent choice for bright-field illumination with the additional advantage of simple brightness adjustments without changing the spectrum. This review discusses the different LED types, their use in the fluorescence microscope, and discusses LED as specialized illumination sources for Förster resonance energy transfer and fluorescent lifetime imaging microscopy.
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