Mesoangioblasti di topo producono e rilasciano nello spazio extracellulare vescicole di membrana contenenti MMP9 e FGF2 in forma attiva

Shedding of membrane vesicles containing HSP70 and FGF-2 from A6 stem cells.

Sistemas de endomembranas (RE y GOLGI), sistema vacuolar y lisosomas

Mouse A6 stem cells release active FGF-2 into extracellular space through plasma membrane vesicles

In this study, mouse mesoangioblasts were seeded onto bidimensional matrices within three-dimensional porous scaffolds of poly (L-lactic acid) (PLLA), in the presence or absence of a type I collagen coating. The cells were observed under a scanning electron microscope and tested for their adhesion, survival and proliferation. Immunolocalization of heat shock protein (Hsp) 70, an abundant and ubiquitous intracellular protein in these cells, was also performed in sectioned cell-containing scaffolds under a confocal fluorescence microscope to determine if in situ analysis of intracellular constituents was feasible. The data show that PLLA films allow direct cell adhesion and represent an optim…

Nichel,piombo e cadmio inducono risposte cellulari differenti, attivando la sintesi di differenti HSP70 in embrioni di ricci di mare

Selezione di cloni più resistenti allo stress ossidativo dalla popolazione di cellule staminali mesoangioblasti

Stress response in mesangioblast stem cells

Mouse mesoangioblast behaviour when subjected to cellular stress

Membrane vesicles containing matrix metalloproteinase-9 and fibroblast growth factor-2 are released into the extracellular space from mouse mesoangioblast Sstem cells

Certain proteins, including fibroblast growth factor-2 (FGF-2) and matrix metalloproteinase-9 (MMP-9), have proved very effective in increasing the efficacy of mesoangioblast stem cell therapy in repairing damaged tissue. We provide the first evidence that mouse mesoangioblast stem cells release FGF-2 and MMP-9 in their active form through the production of membrane vesicles. These vesicles are produced and turned over continuously, but are stable for some time in the extracellular milieu. Mesoangioblasts shed membrane vesicles even under oxygen tensions that are lower than those typically used for cell culture and more like those of mouse tissues. These findings suggest that mesoangioblast…

Stress response and apoptosis in measoangioblast stem cells

Cellule staminali A6 di topo producono vescicole che contengono HSP70 e FGF-2

Autocrine role of extracellular Hsp70 in mesoangioblast migration capability

MMP2 synthesis in mouse mesoangioblast stem cells is highly regulated

Metalloproteasi nella biologia dei mesoangioblasti di topo

Espressione basale dell’HSP70 inducibile in differenti linee staminali di topo.

Another function of Hsp70 in mesoangioblast stem cells

In recent years, it has been demonstrated that Hsp70 is released in the extracellular space under normal cell culture conditions, and this release is mediated through exosomes. We have demonstrated that A6 cells, a clone of mouse mesoangioblasts, produce and release in the extracellular space membrane vesicles, independently of culture growth conditions. These vesicles contains both structural proteins and biological active molecules, such as FGF-2 and the metalloproteinases MMP 2 and 9. We have also demonstrated that A6 vesicles contain HspP70 and its release is highly regulated. Some of the intracellular Hsp70 is localized on lipid rafts and its concentration in insoluble fraction increas…

Cell clone selected from mab stem cell is more resistent to oxidative stress and retain some ability that could be useful for cell therapy.

Extracellular release of Hsp70 from A6 mouse stem cells

Paracrine roles of extracellular vesicles released by mouse mesoangioblasts

Extracellular vesicles (EV) represent an important mediator of cell-to-cell communication and are involved in both autocrine and paracrine signaling, with a critical role in a number of physiological and pathological conditions.1 The bioactive molecules contained within EV simultaneously activate several different pathways resulting in the synergistic stimulation of target cells. The discovery and characterization of EV have added a novel understanding to regenerative medicine, namely the finding that stem cells are an abundant source of EV.1-2 A6 mouse mesoangioblasts, vessel-associated multipotent progenitor stem cells that are capable of differentiating into different mesodermal cell typ…

DNA amplification in sea urchin oocytes.

In situ hybridization of ribosomal RNA withParacentrotus lividus ovaries suggests that ribosomal DNA undergoes amplification in the mononucleolate oocytes of this sea urchin.

Nickel, lead, and cadmium induce differential cellular responses in sea urchin embryos by activating the synthesis of different HSP70s.

Treatment with heavy metals, such as nickel, lead or cadmium, elicits different cellular stress responses according to the metal used and the length of treatment. In Paracentrotus lividus embryos the inducible forms of HSP70 (HSP70/72) are different in molecular mass from the constitutively expressed HSP75, and they can be used as markers of cellular stress. Even a short treatment with each metal induces the synthesis of HSP70/72 which remain stable for at least 20 h and differ little in their isoelectric points. Continuous treatment from fertilization with nickel or lead produces late irregular pluteus embryos, with peak HSP70/72 synthesis at blastula followed by the arrest of synthesis by…

Constitutive hsp70 is essential to mitosis during early cleavage of Paracentrotus lividus embryos: The blockage of constitutive hsp70 impairs mitosis

Localization of constitutive hsp70 in eggs and early embryos of sea urchin Paracentrotus lividus is shown by means of in situ immunostaining. An accumulation of this protein is shown in the mitotic structures (asters, spindles and centrosomes). Microinjection of anti-hsp70 antibodies into eggs causes impairment of formation of mitotic structures and of cell division. This impairment goes from a complete mitotic block, to irregular mitotic apparatus formation with irregular cleavage, depending upon the antibody concentration. The localization of hsp70 after antibody microinjection is also described. Blockage of mitotic apparatus formation by nocodazole also blocks the concentration of hsp70 …

Identification of an HSF2-like factor in sea urchin embryos and its localization in primary mesenchime cells

Intracellular and extracellular Hsp70 in A6 mouse stem cells

Identification and characterization of a constitutive HSP75 in sea urchin embryos.

Abstract An antiserum against a hsp of the 70-kDa family was prepared, by means of a fusion protein, which was able to detect a constitutive 75-kDa hsc in the sea urchinP. lividus.This hsc was present both during oogenesis and at all developmental stages. A two-dimensional electrophoresis has revealed four isolectric forms of this 75-kDa hsc. The amino acid sequence of the fragment used to prepare the anti-hsp70 antibodies revealed a 43% identity with the corresponding part of sea urchin sperm receptor, and in mature eggs a brighter immunofluorescence was seen all around the cell cortex where the receptor for sea urchin sperm is localized. In oocytes the hsp75 was localized in the cytoplasm…

Oxidative stress preconditioning of mouse perivascular myogenic progenitors selects a subpopulation of cells with a distinct survival advantage in vitro and in vivo

AbstractCell engraftment, survival and integration during transplantation procedures represent the crux of cell-based therapies. Thus, there have been many studies focused on improving cell viability upon implantation. We used severe oxidative stress to select for a mouse mesoangioblast subpopulation in vitro and found that this subpopulation retained self-renewal and myogenic differentiation capacities while notably enhancing cell survival, proliferation and migration relative to unselected cells. Additionally, this subpopulation of cells presented different resistance and recovery properties upon oxidative stress treatment, demonstrating select advantages over parental mesoangioblasts in …

Hsp70 and Its Molecular Role in Nervous System Diseases

Heat shock proteins (HSPs) are induced in response to many injuries including stroke, neurodegenerative disease, epilepsy, and trauma. The overexpression of one HSP in particular, Hsp70, serves a protective role in several different models of nervous system injury, but has also been linked to a deleterious role in some diseases. Hsp70 functions as a chaperone and protects neurons from protein aggregation and toxicity (Parkinson disease, Alzheimer disease, polyglutamine diseases, and amyotrophic lateral sclerosis), protects cells from apoptosis (Parkinson disease), is a stress marker (temporal lobe epilepsy), protects cells from inflammation (cerebral ischemic injury), has an adjuvant role i…

Ectosomes containing HSP70 and FGF-2 are released from mouse A6 stem cells

Sea urchin HSF activity in vitro and in transgenic embryos.

Evidence is provided for the presence at the physiological temperature of 20 degrees C of a heat shock transcriptor factor, HSF, in the nuclei of P.lividus embryos. This HSF is able to specifically bind in vitro the heat shock element, HSE, of the promoter of the hsp70 gene i.v., as suggested by DNA-protein binding reactions and DNAse I protection assays. Upon heat-shock, at the temperature of 31 degrees C, its ability to bind the HSE units becomes much higher. The HSF activated by heat-shock drives in vivo the transcription of the beta-galactosidase reporter gene in transgenic sea urchin gastrulae. An ATF-like transcription factor, widely described in other organisms but not at all in sea …

Localization of HSP70, Cdc2, and cyclin B in sea urchin oocytes in non-stressed conditions.

In Paracentrotus lividus embryos, a Mediterranean sea urchin species, HSP70 is present in all the cells. During cell division it localizes under normal growth conditions on the centrosomes and on the whole isolated mitotic apparatus. Now, in situ hybridization, Western blot analyses, and immunohistochemistry show that the HSP70 mRNA is present in both small and large P. lividus oocytes, that all four isoforms of HSP70 can be found also in the oocytes, and that a certain amount of HSP70 localizes on asters and spindles during polar body formation. Moreover, two representative cell-cycle related proteins, cyclin B, and Cdc2, are present both in small and large oocytes, concentrating in the ge…

Hsp70 functions: inside and outside the cell

Studies on heat shock proteins in sea urchin development

Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra- embryonic and intracellular hsp location has…

Differentiation capability of clones of mouse mesoangioblast stem cells resistant to oxidative stress.

Intracellular and extracellular Hsp70 in mouse mesoangioblast stem cells

Studies on sea urchin oocytes. II. Synthesis of RNA during oogenesis.

Abstract Isolated oocytes of the sea urchin Paracentrotus lividus actively incorporate 3H-uridine into RNA. Labeled RNA was analysed by sucrose gradient and acrylamide gel electrophoresis following cell fractionation. Much of the radioactivity is incorporated at the nucleolar level in the form of rRNA precursors. The kinetics of maturation of these latter suggests that this occurs at a slower rate than during embryogenesis. Other non-nucleolar RNA classes are also actively labelled and retained in the nucleus for many hours. These results are confirmed by an autoradiographic investigation.

Starfish and Xenopus oocyte maturation

Treatment with heavy metals, such as nickel, lead or cadmium, elicits different cellular stress responses according to the metal used and the length of treatment. In Paracentrotus lividus embryos the inducible forms of HSP70 (HSP70/72) are different in molecular mass from the constitutively expressed HSP75, and they can be used as markers of cellular stress. Even a short treatment with each metal induces the synthesis of HSP70/72 which remain stable for at least 20h and differ little in their isoelectric points. Continuous treatment from fertilization with nickel or lead produces late irregular pluteus embryos, with peak HSP70/72 synthesis at blastula followed by the arrest of synthesis by …

Hsp70 and NF-kB are involved in mouse mesoangioblast stem cells migration.

Stress response in mouse stem cells

Hsp70 level regulates MMP2 expression in mesoangioblast stemj cells

Mesoangioblast stem cell population is non-omogeneous as revealed by transcriptome analysis after a severe oxidative stress.

Esocitosi di Hsp70 mediante vescicole in cellule staminali di topo

A study on the effect of the inhibition of polyadenylylation on the production of giant cytoplasmic RNA in sea urchin embryos.

It is suggested that inhibition of RNA polyadenylylation in sea urchin mesenchyme blastulae causes a disturbance of the transport of all the size classes of newly synthesized RNA from the nucleus to the cytoplasm.

Heat Shock Proteins in Multiple Sclerosis Pathogenesis: Friend or Foe?

Multiple Sclerosis is a complex chronic inflammatory, neurodegenerative disease conditioned by genetic, epigenetic and environmental factors. Main pathological features of MS include areas of focal demyelination of white matter characterized by gliosis, neuron and oligodendrocyte loss. Neurodegenerative as well as immune-mediated processes play a role in the pathogenesis of this disease. One of these immunogenic factors could be represented by the heat shock proteins. HSP exhibit cytoprotective and cytostimulatory effects due to their molecular chaperones role, in many brain model misfolding diseases such as Alzheimer’s and Parkinson’s diseases, whereas still no unambiguous results have bee…

La regolazione dell’espressione della MMP2 in mesoangioblasti è dipendente dai livelli della proteina Hsp70.

Hsp70 release from mesoangioblast A6 stem cells through vesicles

Sequence of a sea urchin hsp70 gene and its 5' flanking region.

We report the nucleotide sequence of a 4470-bp fragment derived from a sea urchin genomic clone containing part of a heat-shock protein 70 (Hsp70)-encoding gene. This fragment, named hsp70 gene II, contains 1271 bp of the flanking region and 3299 bp of structural gene sequence interrupted by five introns and encoding the N-terminal 371 amino acids (aa) of the protein. The 5' flanking region contains a putative TATA element, two CCAAT boxes, four heat-shock consensus sequence elements (hse) and one consensus sequence for binding of Sp1. Remarkable homologies were observed for deduced aa sequence and intron-exon organization between hsp70 gene II and rat hsc73 gene.

Hsp70 localizes differently from chaperone Hsc70 in mouse mesoangioblasts under physiological growth conditions

Mouse A6 mesoangioblasts express Hsp70 even in the absence of cellular stress. Its expression and its intracellular localization were investigated under normal growth conditions and under hyperthermic stress. Immunofluorescence assays indicated that without any stress a fraction of Hsp70 co-localized with actin microfilaments, in the cell cortex and in the contractile ring of dividing cells, while the Hsc70 chaperone did not. Hsp70 immunoprecipitation assays confirmed that a portion of Hsp70 binds actin. Immunoblot assays showed that both proteins were present in the nucleus. After heat treatment Hsp70 and actin continued to co-localize in the leading edge of A6 cells but not on microfilame…

Hsp70 function inside and outside mouse mesoangioblast stem cells

Isolation of cell clones from stem cell population more resistant to oxidative stress for tissue repair.

A6 stem cells release vesicles containing HSP70i

Armazon celulary organelos: citoesqueleto, mitocondria, peroxisomas y nucleo

MMP2 expression in mouse mesoangioblast is dependent on Hsp70 level.

Territorial localization of heat shock mRNA production in sea urchin gastrulae.

In situ hybridization experiments with a labeled DNA probe indicate that the ability to respond to heat shock with the production of the mRNA for the 70 kd heat shock protein is segregated into the ectodermal cells already at the gastrula stage or earlier during the embryonic development of Paracentrotus lividus.

Hsp70 is required for optimal cell proliferation in mouse A6 mesoangioblast stem cells.

Mouse Hsp70 (70 kDa heat shock protein) is preferentially induced by heat or stress stimuli. We previously found that Hsp70 is constitutively expressed in A6 mouse mesoangioblast stem cells, but its possible role in these cells and the control of its basal transcription remained unexplored. Here we report that in the absence of stress, Ku factor is able to bind the HSE (heat shock element) consensus sequence in vitro, and in vivo it is bound to the proximal hsp70 promoter. In addition, we show that constitutive hsp70 transcription depends on the co-operative interaction of different factors such as Sp1 (specificity protein 1) and GAGA-binding protein with Ku factor, which binds the HSE cons…

Mouse mesoangioblasts release Hsp70 in a controlled manner through membrane vesicle shedding

Mesoangioblaststs (Mabs) are mesodermal stem cells associated with vessels which can differentiate into different mesoderm cell types. They have the property to cross endothelial barrier and when injected into circulation they localize into damaged tissues. A6 cells, a clone of mouse Mabs, express Hsp70 protein in physiological conditions and this synthesis may be required to answer to several intra- and/or extra-cellular needs. It was found that Hsp70 may be released outside from several type of cells, but its role remains still undefined. In order to clarify the reason of Hsp70 constitutive expression, we prepared several A6 clones with different levels of Hsp70 expression by stable RNA i…

Role and regulation of HSP70 in A6 mesoangioblast stem cells

Differences in intercellular communication during clinical relapse and gadolinium-enhanced MRI in patients with relapsing remitting multiple sclerosis: A study of the composition of extracellular vesicles in cerebrospinal fluid

This study was designed based on the hypothesis that changes in both the levels and surface marker expression of extracellular vesicles (EVs) isolated from the cerebrospinal fluid (CSF) may be associated with the clinical form, disease activity, and severity of multiple sclerosis (MS). The analyzes were performed on subjects affected by MS or other neurological disorders. EVs, which were isolated by ultracentrifugation of CSF samples, were characterized by flow cytometry. A panel of fluorescent antibodies was used to identify the EV origin: CD4, CCR3, CCR5, CD19, and CD200, as well as isolectin IB4. The Mann–Whitney U-test and Kruskal–Wallis test were used for statistical analyzes. EVs isol…

A sub-population of mesoangioblasts displays features of resistance and proliferation confirmed by transcriptome analysis.

A6 stem cells culture into a biodegradable PLLA scaffold

The migration capability of mouse mesoangioblast stem cells depends on Hsp autocrine signalling.

Extracellular vesicles isolated by cerebrospinal fluid as biomarkers of inflammation in multiple sclerosis and inflammatory neurological diseases.

Characterization of a new member of the sea urchin Paracentrotus lividus hsp70 gene family and its expression

We have sequenced a second gene of the hsp70 family derived from a genomic clone of the sea urchin, Paracentrotus lividus. The structure of this gene, named hsp70IV gene, is interrupted by one intron and differs from the previously analyzed sea urchin hsp70II gene, which contains several introns. Two open reading frames of hsp70IV gene encode a predicted protein of 639 amino acids with an M(r) of 69,672. The 5' flanking region of the gene contains a putative TATA element, three heat-shock elements made up of some arrays of the 5-bp units, NGAAN and NTTCN (N = A,C,G or T), a canonic consensus sequence for binding of the regulatory activating transcription factor (ATF), and a purine box. The …

Parkinson's disease and cancer: insights for pathogenesis from epidemiology .

Epidemiological evidence suggests a reduced incidence of many common types of cancers in individuals with Parkinson's disease (PD). Parkinson's disease and cancer are two diseases that result from an excessive signaling by one of two forces driving cells to opposite directions. PD results from the excessive death of dopaminergic neurons in the substantia nigra pars compacta (SNc) in the brain, while uncontrolled growth is the key property of cancer. Parkinson's disease is a complex disorder, probably due in most of the cases to the interaction of environment and genes. Many genes responsible for familial forms of PD are supposed to have a supportive role in regulating or maintaining the cel…

Mesoangioblast MMP2 regulation is dependent on Hsp70 level

Protective role of heat shock proteins in Parkinson's disease.

Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease. Despite a large amount of research, the pathogenetic mechanism of these diseases has not yet been clarified. Abnormal protein folding, oxidative stress, mitochondrial dysfunction, and apoptotic mechanisms have all been reported as causes of neurodegenerative diseases in association with neuroinflammatory mechanisms which, by generating deleterious molecules, could promote the cascade of events leading to neurodegeneration. Heat shock proteins (HSPs) play a central role in preventing protein misfolding and inhibiting apoptotic activity, and represent a class of proteins potentially involve…

Stress response in mesoangioblast stem cells

Stem cells are presumed to survive various stresses, since they are recruited to areas of tissue damage and regeneration, where inflammatory cytokines and cytotoxic cells may result in severe cell injury. We explored the ability of mesoangioblasts to respond to different cell stresses such as heat, heavy metals and osmotic stress, by analyzing heat shock protein (HSP)70 synthesis as a stress indicator. We found that the A6 mesoangioblast stem cells constitutively synthesize HSP70 in a heat shock transcription factor (HSF)-independent way. However, A6 respond to heat shock and cadmium treatment by synthesizing HSP70 over the constitutive expression and this synthesis is HSF1 dependent. The e…

Synthesis of a porous and biodegradable PLLA scaffold for application of tissue engineering

Analisi dell’espressione dell’HSP70 inducubile in cellule staminali ed in tessutiu adulti di topo.

Effects of H2O2 on mesoangioblast stem cells: survival and cell death

Myo-inositol counteracts the vegetalizing effect of lithium on P.lividus embryos

Abstract The vegetalizing effect of LiCl on sea urchins embryos can be counteracted by the addition of myo-inositol. This observation is discussed in connection with similar results recently reported for amphibian embryos.

Shedding of vesicles from mesoangioblast A6 stem cells

Mesoangioblast behaviour in oxidative stress condition

Hsp70 in mesoangioblast A6 stem cells.

Extracellular Hsp70 Enhances Mesoangioblast Migration via an Autocrine Signaling Pathway

Mouse mesoangioblasts are vessel-associated progenitor stem cells endowed with the ability of multipotent mesoderm differentiation. Therefore, they represent a promising tool in the regeneration of injured tissues. Several studies have demonstrated that homing of mesoangioblasts into blood and injured tissues are mainly controlled by cytokines/chemokines and other inflammatory factors. However, little is known about the molecular mechanisms regulating their ability to traverse the extracellular matrix (ECM). Here, we demonstrate that membrane vesicles released by mesoangioblasts contain Hsp70, and that the released Hsp70 is able to interact by an autocrine mechanism with Toll-like receptor …

Capacità di differenziamento di un clone cellulare da cellule staminali resistenti allo stress ossidativo.

Porous PLLA scaffolds are optimal substrates for internal colonization by A6 mesoangioblasts and immunocytochemical analyses

In the present paper, mouse mesoangioblasts were seeded onto bidimensional matrices and within three-dimensional porous scaffolds of poly(L-lactic acid) (PLLA), in the presence or absence of type I collagen coating, observed under the scanning electron microscope, and tested for their adhesion, survival and proliferation. Immunolocalization of Hsp70, an abundant and ubiquitous intracellular protein in these cells, was also performed in sectioned cell-containing scaffolds under the confocal fluorescence microscope to check whether "in situ" analysis of intracellular constituents was feasible. The data obtained show that PLLA films allow direct cell adhesion and represent an optimal support f…

Heat-Shock Proteins in Sea Urchin Embryos

The production of heat-shock proteins in sea urchin embryos is accompanied by the appearance at the polysomal level of their relative mRNAs, as shown by their translation in a cell-free system; thus suggesting that the regulation of their production occurs at a transcriptional level. The mechanism for the inhibition of the bulk protein synthesis and for its reversal on the other hand should be looked for at a posttranscriptional level, since both these phenomena occur also in the presence of actinomycin D. The heat-shock proteins produced as early as at the mesenchyme blastula stage persist within the embryo at least till the pluteus stage.

Ciclo celular, apoptosis y envejecimiento

H2O2 resistant mesoangioblast clone isolation with a distinct survival advantage in vitro and in vivo

The release of molecules from damaged tissues stimulates both resident and circulating stem cells to initiate a tissue repair programme. 1 However, during transplantation procedures the therapeutic efficacy of stem cells is compromised by reduced homing capability towards the target site.2,3 Furthermore, cell survival is very low and many studies focused on improving cell viability upon implantation. In this study, we performed in vitrosevere oxidative stress to select some more resistant mouse mesoangioblasts, vessel-associated progenitor stem cells endowed with the ability of multipotent mesoderm differentiation. We found that the selected subpopulation retains selfrenewal and myogenic di…

Autophagy and apoptosis regolate survival of mesoangioblast stem cells subjected to oxidative stress

Mesoangioblast A6 stem cells release vesicles containing the inducible HSP70

Ku factor is responsible of Hsp70 basal transcription in mouse mesoangioblasts

Inducible HSP70 localization in mesoangioblast A6 stem cells

Hsp70 is involved in MMP2 level in mouse mesoangioblast stem cells

Extracellular membrane vesicles as a mechanism of cell-to-cell communication: advantages and disadvantages.

Microvesicles represent a newly identified mechanism of intercellular communication. Two different types of microvesicles have been identified: membrane-derived vesicles (EVs) and exosomes. EVs originate by direct budding from the plasma membrane, while exosomes arise from ectocytosis of multivesicular bodies. Recent attention has focused on the capacity of EVs to alter the phenotype of neighboring cells to make them resemble EV-producing cells. Stem cells are an abundant source of EVs, and the interaction between stem cells and the microenvironment (i.e., stem cell niche) plays a critical role in determining stem cell phenotype. The stem cell niche hypothesis predicts that stem cell number…

Acquisition of thermotolerance in sea urchin embryos correlates with the synthesis and age of the heat shock proteins.

Preheating at 31 degrees C induces thermotolerance in Paracentrotus lividus embryos, which therefore become able to withstand 1-h treatment at the otherwise lethal temperature of 35 degrees C, and to develop normally. The acquisition of thermotolerance is positively correlated with the amount of heat shock proteins produced during the 31 degrees C treatment. Evidence is provided that the heat shock proteins, although present in the embryo for long periods after synthesis, lose their effect on thermotolerance within 3 h of the cessation of synthesis.

Cell clones more resistant to oxidative stress selecte from embryonic and adult mesoangioblast stem cell population.

Transcriptome analysis after a strong oxidative stress highlighted a mesoangioblast stem cell sub-population with important different capability

Rapid changes in heat-shock cognate 70 levels, heat-shock cognate phosphorylation state, heat-shock transcription factor, and metal transcription factor activity levels in response to heavy metal exposure during sea urchin embryonic development.

The aim of the present study was to analyze and compare the effects of several metals on the embryos of the sea urchin Paracentrotus lividus, a key species within the Mediterranean Sea ecosystem. Embryos were continuously exposed from fertilization to the following metals: 0.6 mg/l copper, 3 mg/l lead, and 6 mg/l nickel. The embryos were then monitored for metal responses at the gastrula stage, which occurred 24 h after exposure. A biochemical multi-experimental approach was taken and involved the investigation of the levels of HSC70 expression and the involvement of heat shock factor (HSF) and/or metal transcription factor (MTF) in the response. Immunoblotting assays and electrophoretic mo…

Regeneration in invertebrates

The mechanisms of regeneration are reviewed from a genetic, cytological and molecular biological points of view. Planarians and Hydra have been chosen and illustrated as biological examples.