Autofluorescence of living cells

Andersson, Helene; Baechi, Thomas; Hoechl, M; Richter, Christoph

doi:10.1046/j.1365-2818.1998.00347.x

Cited by 183 publications

(144 citation statements)

References 9 publications

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“…On the contrary, in control cells, the discrete fluorescent sites were strongly reduced and a homogeneous fluorescence was spread in the cytoplasm. It has been demonstrated that the intracellular autofluorescent sites co-localize with mitochondria and, to a lesser extent, with lysosomes [Andersson et al, 1998]. Therefore, our findings assessed a higher content of mitochondria in the cells cultured in modeled hypogravity than in the control ones.…”

Section: Discussionmentioning

confidence: 57%

“…1.3), under 365 nm excitation from a filtered (10 nm bandwidth interference filter, 365FS10-25, Andover), high-pressure mercury lamp (HBO 100 W, Osram). The 365 nm wavelength is particularly suitable for NAD(P)H, but able to excite flavins and lipopigments too [Andersson et al, 1998]. In this way, the most important endogenous fluorophores emitting in the visible range were detected at the same time.…”

Section: Multispectral Imaging Autofluorescence Microscopy and Autoflmentioning

confidence: 99%

“…These wavelengths correspond to the emission peaks of the NAD(P)H bound form, NAD(P)H free form and flavins, respectively [Andersson et al, 1998]. Table II reports the AF intensity ratios 445 nm/530 nm and 465 nm/530 nm, calculated from the spectra of cells kept in modeled hypogravity and controls.…”

Section: Multispectral Imaging Autofluorescence Microscopy and Autoflmentioning

confidence: 99%

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Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells

et al. 2006

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Gravity acts permanently on organisms as either static or dynamic stimulation. Understanding the influence of gravitational and mechanical stimuli on biological systems is an intriguing scientific problem. More than two decades of life science studies in low g, either real or modeled by clinostats, as well as experimentation with devices simulating different types of controlled mechanical stimuli, have shown that important biological functions are altered at the single cell level. Here, we show that the human leukemic line FLG 29.1, characterized as an osteoclastic precursor model, is directly sensitive to gravitational unloading, modeled by a random positioning machine (RPM). The phenotypic expression of cytoskeletal proteins, osteoclastic markers, and factors regulating apoptosis was investigated using histochemical and immunohistochemical methods, while the expression of the corresponding genes was analyzed using RT-PCR. A quantitative bone resorption assay was performed. Autofluorescence spectroscopy and imaging were applied to gain information on cell metabolism. The results show that modeled hypogravity may trigger both differentiation and apoptosis in FLG 29.1 cells. Indeed, when comparing RPM versus 1 Â g cultures, in the former we found cytoskeletal alterations and a marked increase in apoptosis, but the surviving cells showed an osteoclastic-like morphology, overexpression of osteoclastic markers and the ability to resorb bone. In particular, the overexpression of both RANK and its ligand RANKL, maintained even after return to 1 Â g conditions, is consistent with the firing of a differentiation process via a paracrine/autocrine mechanism. J. Cell. Biochem. 98: 65-80, 2006. ß 2005 Wiley-Liss, Inc.Key words: weightlessness; preosteoclastic differentiation; apoptosis; bone resorption; osteoporosis; gene expressionThe importance of gravity in modulating some biological processes, such as plant gravitropism and the adaptation of the vertebrate skeleton in relation to its load-bearing function, has long been known. Nevertheless, the role of gravity and other mechanical factors in biological processes is far from clear. A weightless environment is a powerful tool for understanding this role and for studying the related cellular and molecular mechanisms. Several investigations conducted in space laboratories and with instruments averaging the gravity vector, and thus simulating conditions of reduced gravity, have shown that isolated cells may change their behavior under altered gravitational conditions. Loss of cell activation [Cogoli et al., 1984], perturbation of signal transduction [Schmitt et al., 1996;Hashemi et al., 1999] and modification of genetic expression [Walther et al., 1998;Hammond et al., 1999] have been described. This suggests that some of the mechanisms at the roots of the systemic effects observed in weightlessness, such as depression of the immune system [Gmü nder and Cogoli, 1996]

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Section: Discussionmentioning

confidence: 57%

Section: Multispectral Imaging Autofluorescence Microscopy and Autoflmentioning

confidence: 99%

Section: Multispectral Imaging Autofluorescence Microscopy and Autoflmentioning

confidence: 99%

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Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells

et al. 2006

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“…A cell's autofluorescence is indicative of the mitochondrial, cytoplasmic vesicle, nicotinamide adenine dinucleotide (NADH), and flavin content of the cell. 23,24 In this study, cytokine stimulation enhanced Cytokine-induced immunoregulatory properties JL Banyer et al the level of autofluorescence from the cells compared with the GM-CSF progenitor cells. This is likely to reflect the increased vacuole and exosome content of the cells as detected by TEM analysis.…”

Section: Ifn-c and Il-4 Differentially Effect The Morphology Of The Mmentioning

confidence: 64%

Combinations of IFN-γand IL-4 induce distinct profiles of dendritic cell-associated immunoregulatory properties

et al. 2003

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Interferon gamma (IFN-g) and interleukin-4 (IL-4) are not only generated during cell-mediated immunity (CMI) and humoral immunity (HI), but are also generated by innate immune cells in response to pathogenic factors. How these cytokines differentially effect the development of dendritic cell (DC)-associated immunoregulatory properties from progenitor cells during innate immunity is unresolved. To address this we have utilized a homogeneous DC progenitor-like cell line, MTHC-D2, as a model to examine cytokine-induced maturation of DCs. By 6 h IFN-g induced genes that are important for antiviral activity and development of CMI, whereas IL-4 induced genes involved in cellular adhesion, uptake of extracellular antigen, suppression of cytotoxic T-cell responses, and that repair the extracellular matrix. By 48 h the cytokine stimulus had induced many properties characteristic of immature DCs; however, these were differentially effected by IFN-g and IL-4. IFN-g induced the greatest levels of costimulatory/ activation marker expression, and the highest levels of T-cell proliferation, whereas IL-4 induced the greatest levels of phagocytic activity. Stimulation of the cells with CD40 Ab enhanced the levels of costimulatory marker expression and T-cell stimulatory capacity of cells exposed to IFN-g, but had little effect on cells exposed to IL-4 in the absence of IFN-g.

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“…The mechanisms responsible for the larger amount of auto-fluorescence in the notochordal-like cell population are unknown, but they may be related to the presence of large vacuoles [22] or inclusion bodies [12] uniquely identified in this cell population. The auto-fluorescence from the endogenous intracellular coenzyme NAD(P)H and the oxidized lipid or flavoprotein has also been used to image living cells [2], as well as to distinguish normal and tumor cells [3]. The FACS protocol used here Nd not detected, › higher than AF cells, fl lower than AF cells S309 combined sorting methods by both cell size and autofluorescence, as size was believed to be an important distinguishing feature of notochordal-like cells based on prior knowledge.…”

Section: Discussionmentioning

confidence: 99%

Molecular phenotypes of notochordal cells purified from immature nucleus pulposus

2006

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The immature nucleus pulposus (NP) is populated by cells of notochordal-origin that are larger and contain an extensive cytoskeletal network and numerous vacuoles. The disappearance of these cells with age is believed important in regulating metabolic shifts that may contribute to age-related disc degeneration. The precise biological function of these notochordal cells in the immature NP remains unclear, however, because of challenges in studying the mixed cell population in the NP. In this study, notochordallike cells were purified from immature NP cells using a new fluorescence-activated cell sorting (FACS) protocol with auto-fluorescence and size analysis. The unique molecular phenotypes of sorted notochordallike cells were characterized by the mRNA expression pattern for key matrix proteins and modulators, and by the expression of cell-matrix receptor integrin subunits. An FACS analysis showed that the immature NP contained a majority of cells that were larger than anulus fibrosus (AF) cells and with fluorescence higher than AF cells. In comparison with the small NP cells separated by the FACS protocol, sorted notochordal-like cells expressed lower mRNA levels of type I collagen, biglycan, TIMP1, HSP70 and c-fos, and did not express detectable mRNA levels of decorin, lumican, multiple MMPs or IL-1b via realtime quantitative RT-PCR. A greater number of these notochordal-like cells also expressed the higher levels of a6, a1 and b1 integrin subunits as compared to small NP cells. Together, our results point towards a unique molecular phenotype for these notochordal-like cells of NP, characterized by the absence of gene expression for specific small proteoglycans and higher protein expression of integrin subunits that regulate interactions with collagens and laminin. Future studies will be important for revealing if this unique molecular profile is coordinated with functional differences in pericellular matrix regions and/or integrin-mediated cell-matrix interactions for these notochordallike cells within the NP.

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Autofluorescence of living cells

Cited by 183 publications

References 9 publications

Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells

Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells

Combinations of IFN-γand IL-4 induce distinct profiles of dendritic cell-associated immunoregulatory properties

Molecular phenotypes of notochordal cells purified from immature nucleus pulposus

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