PubMed Health⌕ Search

Biomedical subjects

Augusto Cogoli

Publications and source records attributed to Augusto Cogoli.

14 recordsLinked to original sources
PubMed2006

Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells.

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 x 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 x g conditions, is consistent with the firing of a differentiation process via a paracrine/autocrine mechanism.

Apoptosis↗
PubMed2006

Simulated weightlessness changes the cytoskeleton and extracellular matrix proteins in papillary thyroid carcinoma cells.

Studies of astronauts, experimental animals, and cells have shown that, after spaceflights, the function of the thyroid is altered by low-gravity conditions. The objective of this study was to investigate the cytoskeleton and extracellular matrix (ECM) protein synthesis of papillary thyroid cancer cells grown under zero g. We investigated alterations of ONCO-DG 1 cells exposed to simulated microgravity on a three-dimensional random-positioning machine (clinostat) for 30 min, 24 h, 48 h, 72 h, and 120 h (n=6, each group). ONCO-DG 1 cells grown under microgravity exhibited early alterations of the cytoskeleton and formed multicellular spheroids. The cytoskeleton was disintegrated, and nuclei showed morphological signs of apoptosis after 30 min. At this time, vimentin was increased. Vimentin and cytokeratin were highly disorganized, and microtubules (alpha-tubulin) did not display their typical radial array. After 48 h, the cytoskeletal changes were nearly reversed. The formation of multicellular spheroids continued. In parallel, the accumulation of ECM components, such as collagen types I and III, fibronectin, chondroitin sulfate, osteopontin, and CD44, increased. The levels of both transforming growth factor beta-1 (TGF-beta(1)) and TGF-beta receptor type II proteins were elevated from 24 h until 120 h clinorotation. Gene expression of TGF-beta(1) was clearly enhanced during culture under zero g. The amount of E-cadherin was enhanced time-dependently. We suggest that simulated weightlessness rapidly affects the cytoskeleton of papillary thyroid carcinoma cells and increases the amount of ECM proteins in a time-dependent manner.

Carcinoma, Papillary↗
PubMed2005

Simulated hypogravity impairs the angiogenic response of endothelium by up-regulating apoptotic signals.

Health hazards in astronauts are represented by cardiovascular problems and impaired bone healing. These disturbances are characterized by a common event, the loss of function by vascular endothelium, leading to impaired angiogenesis. We investigated whether the exposure of cultured endothelial cells to hypogravity condition could affect their behaviour in terms of functional activity, biochemical responses, morphology, and gene expression. Simulated hypogravity conditions for 72 h produced a reduction of cell number. Genomic analysis of endothelial cells exposed to hypogravity revealed that proapoptotic signals increased, while antiapoptotic and proliferation/survival genes were down-regulated by modelled low gravity. Activation of apoptosis was accompanied by morphological changes with mitochondrial disassembly and organelles/cytoplasmic NAD(P)H redistribution, as evidenced by autofluorescence analysis. In this condition cells were not able to respond to angiogenic stimuli in terms of migration and proliferation. Our study documents functional, morphological, and transcription alterations in vascular endothelium exposed to simulated low gravity conditions, thus providing insights on the occurrence of vascular tissue dysregulation in crewmen during prolonged space flights. Moreover, the alteration of vascular endothelium can intervene as a concause in other systemic effects, like bone remodelling, observed in weightlessness.

Animals↗
PubMed2005

Early immune response and regulation of IL-2 receptor subunits.

Affymetrix oligonucleotide arrays were used to monitor expression of 8796 genes and probe sets in activated T-cells; analysis revealed that 217 genes were significantly upregulated within 4 h. Induced genes included transcription factors, cytokines and their receptor genes. Analysis by semi-quantitative RT-PCR confirmed the significant induction of IL-2, IL-2R(gamma) and IL-2R(alpha). Forty-eight of the 217 induced genes are known to or predicted to be regulated by a CRE promoter/enhancer. We found that T-cell activation caused a significant increase in CREB phosphorylation furthermore, inhibition of the PKC pathway by GF109203 reduced CREB activation by 50% and inhibition of the PKA pathway caused a total block of CREB phosphorylation and significantly reduced IFN(gamma), IL-2 and IL-2R(alpha) gene expression by approximately 40% (p<0.001). PKC(theta) plays a major role in T-cell activation: inhibition of PKC significantly reduced the expression of IFN(gamma), IL-2 and IL-2R(alpha). Since PKC blocked activation of CREB, we studied potential cross-talk between the PKC and the PKA/MAPK pathways, PMA-stimulated Jurkat cells were studied with specific signal pathway inhibitors. Extracellular signal-regulated kinase-2 (ERK2) pathway was found to be significantly activated greater than seven-fold within 30 min; however, there was little activation of ERK-1 and no activation of JNK or p38 MAPK. Inhibition of the PKA pathway, but not the PKC pathway, resulted in inhibition of ERK1/2 activation at all time points, inhibition of MEK1 and 2 significantly blocked expression of IL-2 and IL-2R(alpha). Gene expression of IL-2R(alpha) and IFN(gamma) was dependent on PKA in S49 wt cells but not in kin- mutants. Using gel shift analysis, we found that forskolin activation of T-cells resulted in activation of AP1 sites; this increase in nuclear extract AP1 was significantly blocked by MEK1 inhibitor U0126. Taken together, these results suggest that the PKA in addition to PKC and MAPK pathways plays a role in early T-cell activation and induction of IL-2, IL-2R(alpha) and IFN(gamma) gene expression.

Cyclic AMP↗
PubMed2004

Strategies of cell biology experimentation in space.

The purpose of this article is to inform newcomers on the most important aspects of experimentation with living cells and tissues in space laboratories and platforms. There are strong arguments that justify the efforts and investments in such activity. Experimentation in space is subject to safety and technological constraints that require considerable attention to the development of the flight protocols and of the flight instrumentation. Nevertheless to fly an experiment in space is a unique opportunity to study living systems under conditions not reproducible on Earth and it is also a contribution to human exploration of space. Thereby important progress in basic and applied science can be expected. Parallel investigations on ground with devices averaging the exposure to the gravity vector but not reproducing microgravity shall always be part of a space flight project.

Cell Culture Techniques↗
PubMed2004

Longterm conditions of mimicked weightlessness influences the cytoskeleton in thyroid cells.

Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle atrophy and cardiac atrophy. Effects on control mechanisms for proliferation, programmed cell death and differentiation are well documented. The principal aim of this study was to investigate changes of the cytoskeleton in thyroid cells cultured in vector-averaged gravity under clinostat rotation. After 12 hours the formation of multicellular spheroids started. An increase of extracellular matrix proteins and beta 1-integrin was observed. Laser scanning confocal microscopy of ML-1 follicular thyroid carcinoma cells and normal thyroid HTU-5 cells immunostained with anti-cytokeratin to demonstrate these intermediate filaments revealed that cytokeratin filaments extended from centers, were thickened, coalesced and shortened as compared to control cells. Moreover, vimentin was highly disorganized. The vimentin network formed a coiled aggregate closely associated with the nucleus. Western blot analyses of talin, alpha- and beta-tubulin showed a clear increase of these proteins in cells cultured under simulated 0 g. Our data suggest that the effects of microgravity on cultured human thyroid cells are accompanied by noticeable functional cellular changes. Future studies to clarify the pathway that regulate the observed integrin activation and the mechanisms by which they function have to be performed.

Cell Differentiation↗
PubMed2004

Vascular endothelial growth factor inhibits programmed cell death of endothelial cells induced by clinorotation.

The principal aim of this study was to investigate short- and long-term effects of clinorotation on human endothelial cells (EA hy 926 cell line) using a three-dimensional random positioning machine. Moreover, the impact of vascular endothelial growth factor (VEGF) was addressed. Immediately, within one hour and after four and twenty-four hours an increase of apoptotic cells was detected. VEGF significantly inhibited the amount of apoptotic endothelial cells (EC). VEGF reduced the amount of fas-positive EC. Moreover, after 24 hours, proliferating EC grew in form of three-dimensional multicellular spheroids and also as monolayers. The initially formed spheroids (maximum diameter 3 mm) remained stable up to the 15th day of clinorotation. Some spheroids revealed tubular structures. In addition, a clear increase of extracellular matrix proteins such as osteopontin and fibronectin was measured. The three-dimensional clinostat represents an important tool for cell biological experiments. VEGF significantly attenuated the changes of endothelial cells induced by simulated weightlessness in a cell protective manner.

Apoptosis↗
PubMed2003

Creating conditions similar to those that occur during exposure of cells to microgravity induces apoptosis in human lymphocytes by 5-lipoxygenase-mediated mitochondrial uncoupling and cytochrome c release.

Creating conditions similar to those that occur during exposure of cells to microgravity induced a sixfold increase of apoptotic bodies and DNA fragments in human lymphocytes, paralleled by an early (within 2 h) fourfold increase in 5-lipoxygenase (5-LOX) activity and a fivefold decrease in mitochondrial membrane potential and increase in cytochrome c release (within 4 and 8 h, respectively). Similar membrane potential and cytochrome c release were observed in isolated mitochondria treated with physiological amounts of 5-LOX and were enhanced by creating conditions similar to those that occur during exposure of cells to microgravity. 5-LOX inhibitors, 5,8,11,14-eicosatetraynoic acid and caffeic acid, completely prevented apoptosis, whereas the phospholipase A(2) inhibitor methyl-arachidonoyl fluorophosphonate and the 5-LOX activating protein inhibitor MK886 reduced it to 65-70%. The intracellular calcium chelator EGTA-acetoxymethylester reduced 5-LOX activity and apoptosis to 30-40% of controls, whereas the p38 mitogen-activated protein kinase inhibitor SB203580 was ineffective. The caspase-3 and caspase-9 inhibitors Z-Asp(OCH(3))-Glu(OCH(3))-Val-Asp(OCH(3))-fluoromethylketone (FMK) and Z-Leu-Glu(OCH(3))-His-Asp(OCH(3))-FMK reduced apoptotic bodies to 25-30% of the control cells. Finally, creating conditions similar to those that occur during exposure of cells to microgravity did not induce apoptosis in human lymphoma U937 cells, which did not express an active 5-LOX.

Adult↗
PubMed2003

Weightlessness induced apoptosis in normal thyroid cells and papillary thyroid carcinoma cells via extrinsic and intrinsic pathways.

Apoptosis plays a pivotal role in development, tissue homeostasis, cancer, immune defense, and response to weightlessness. It can be initiated by external signals via death receptors, but may also emerge from mitochondria. We exposed mitochondria-rich thyroid carcinoma cells (ONCO-DG1 cell line) and normal thyroid cells (HTU-5) to conditions of simulated microgravity. After 24 h, 10% of the cancer cells had entered a Fas-dependent apoptotic pathway, but destruction and redistribution of mitochondria, microtubuli disruption, and caspase-3 activation were also detected, demonstrating the activation of extrinsic as well as intrinsic pathways. Furthermore, ONCO-DG1 cells grown on the clinostat showed elevated amounts of Bax, but reduced quantities of bcl-2. In addition, signs of apoptosis became detectable, as assessed by terminal deoxynucleotidyl transferase-mediated dUTP digoxigenin nick end labeling, 4',6-diamidino-2-phenylindole staining, and 85-kDa apoptosis-related cleavage fragments. These fragments resulted from enhanced 116-kDa poly(ADP-ribose)polymerase activity and apoptosis. Apoptosis was also detected in normal HTU-5 cells, as demonstrated by electron microscopy, activation of caspase-3, increases in Fas and Bax, and elevation of 85-kDa apoptosis-related cleavage fragments resulting from enhanced poly(ADP-ribose) polymerase activity. Gravitational unloading affects the mitochondria and thereby may trigger apoptosis in thyroid cells subjected to weightlessness by clinorotation.

Apoptosis↗
PubMed2003

Space Biology Group: basic research, biotechnology, tissue engineering, and instrument development.

At the beginning of space flight, the investigations were oriented essentially toward the health of the astronauts. But in the last three decades space biology has evolved from "try-and-see" experiments to sophisticated basic and applied research with well-based hypotheses as well as studies on the use of low gravity in biological applications. In 1977 the Space Biology Group of the Swiss Federal Institute of Technology, Zurich, began its activities in space research. A summary of the experiments performed to date, from basic research on the human immune system to the development of sophisticated instruments for biotechnology and medical application, is presented here.

Aerospace Medicine↗
PubMed2002

Simulated microgravity alters differentiation and increases apoptosis in human follicular thyroid carcinoma cells.

This study focuses on the effects of simulated microgravity (0g) on the human follicular thyroid carcinoma cell line ML-1. Cultured on a three-dimensional clinostat, ML-1 cells formed three-dimensional MCTSs (MCTS diameter: 0.3 +/- 0.01 mm). After 24 and 48 h of clinorotation, the cells significantly decreased fT3 and fT4 secretion but up-regulated the thyroid-stimulating hormone-receptor expression as well as the production of vimentin, vinculin, and extracellular matrix proteins (collagen I and III, laminin, fibronectin, chondroitin sulfate) compared with controls. Furthermore, ML-1 cells grown on the clinostat showed elevated amounts of the apoptosis-associated Fas protein, of p53, and of bax but showed reduced quantities of bcl-2. In addition, signs of apoptosis became detectable, as assessed by terminal deoxynucleotidyl transferase-mediated dUTP digoxigenin nick end labeling, 4', 6-diamidino-2-phenylindole staining, DNA laddering, and 85-kDa apoptosis-related cleavage fragments. These fragments resulted from enhanced 116-kDa poly(ADP-ribose)polymerase (PARP) activity and apoptosis. These observations suggest that clinorotation elevates intermediate filaments, cell adhesion molecules, and extracellular matrix proteins and simultaneously induces apoptosis in follicular thyroid cancer cells. In conclusion, our experiments could provide a regulatory basis for the finding that astronauts show low thyroid hormone levels after space flight, which may be explained by the increase of apoptosis in thyrocytes as a result of simulated 0g.

Adenocarcinoma, Follicular↗
PubMed2002

Effects of simulated microgravity on thyroid carcinoma cells.

We aimed to investigate whether simulated microgravity on thyroid carcinoma cells could help to perform in vitro cancer studies such as antitumor drug tests more reliable and to spare animal experiments. We cultured cancer cells at 0 g to enable formation of three-dimensional multicellular tumor spheroids (MCTS), which will resemble the originating tumors. Under microgravity human follicular cells (ML-1 cell line) keep floating with-out stirring so that initial cell-cell interactions required for spheroid formation will be induced by forces due to biochemical components actually expressed on surfaces of cells, whereas gravity related push- or shear events will not influence MCTS formation. Within 12 hours of clinorotation the monolayer turned spontaneously into MCTS with remarkable features: An increase of extracellular matrix proteins and TGF-beta 1. Thyroglobulin, ft3 and ft4 secretion were markedly reduced. These data are in agreement with the observation that astronauts show low thyroid hormone levels after spaceflight.

Journal Article↗
PubMed2002

Simulated microgravity induces programmed cell death in human thyroid carcinoma cells.

The present study focused on the effects of simulated microgravity on the human follicular thyroid carcinoma cell line ML-1. Cultured on a three-dimensional clinostat ML- 1 cells formed three-dimensional multicellular tumor spheroids (MCTS: 0.3 +/= 0.01mm in diameter). Furthermore, ML-1 cells grown on the clinostat showed elevated amounts of the apoptosis-associated Fas protein, of p53 and of bax, but reduced quantities of bcl-2. In addition, signs of apoptosis as assessed by TdT-mediated DUTP digoxigenin nick end labeling, DAPI staining, DNA laddering and 85-kDa apoptosis-related DNA fragments became detectable. The latter ones resulted from enhanced 116-kDa poly(ADP-ribose)polymerase activity. Electron microscopy revealed all morphological signs of apoptosis. Caspase 3 was clearly upregulated. In conclusion, our experiments show that conditions of simulated microgravity induce early programmed cell death and use different pathways of apoptosis.

Journal Article↗