Biomedical subjects

Vanessa Nicolin

Publications and source records attributed to Vanessa Nicolin.

9 recordsLinked to original sources

PubMed2006

Morphological features of osteoclasts derived from a co-culture system.

The interaction between the receptor activator of NfKB (RANK) and its ligand receptor activator of NfKB ligand (RANKL) has recently been proven to be pivotal for osteoclast differentiation and activation. The influence of RANK-RANKL signaling on osteoclast formation was established by co-culturing murine osteoblasts (type CRL-12257) and murine mononuclear monocytes (RAW 264.7). The aim of the present study was to examine, by means of morphological techniques, the interaction between these two cell lines grown in the absolute absence of exogenous cytokines and other stimulating factors. Moreover, we wanted to show that our model could provide a system to analyze the bone resorption process. Mineralized matrix induced morphological changes of osteoclasts (OC) by the formation of organized ruffled-border and a large number of secondary lysosomal vesicles. On the contrary, OC grown on glass coverslips without dentin showed no organized ruffled border or secondary lysosomes. The study of the relationship between these two cell types could establish new approaches for a potential pharmacological control of these cell types and tissues in health and disease.

Animals↗

PubMed2006

TRAIL, caspases and maturation of normal and leukemic myeloid precursors.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a membrane-bound cytokine molecule that belongs to the family of tumor necrosis factor (TNF). Members of this family share diverse biological effects, including induction of apoptosis and/or promotion of cell survival. Identification of TRAIL has generated considerable enthusiasm for its ability to induce apoptotic cell death in a variety of tumor cells, by engaging the death receptors TRAIL-R1/DR4 and TRAIL-R2/DR5, while sparing most normal cells. Beside its anticancer activity, several studies have suggested a role for endogenously expressed TRAIL in hemopoiesis. In this review, we summarize the knowledge about the different lineage-specific roles of TRAIL and its receptors in hemopoiesis regulation. Moreover, the complex interplay among the signaling pathways triggered by TRAIL/TRAIL-receptors in myeloid cells is discussed in some detail.

Apoptosis↗

PubMed2005

Different levels of the neuronal nitric oxide synthase isoform modulate the rate of osteoclastic differentiation of TIB-71 and CRL-2278 RAW 264.7 murine cell clones.

It has been clearly established that osteoclasts, which play a crucial role in bone resorption, differentiate from hematopoietic cells belonging to the monocyte/macrophage lineage in the presence of macrophage-colony stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL). We have here investigated the M-CSF- and RANKL-induced osteoclastic differentiation of two distinct clones of the murine monocytic/macrophagic RAW 264.7 cell line, known as TIB-71 and CRL-2278, the latter cell clone being defective for the expression of the inducible nitric oxide synthase isoform in response to interferon-gamma or lipopolysaccharide. CRL-2278 cells demonstrated a more rapid osteoclastic differentiation than TIB-71 cells, as documented by morphology, tartrate-resistant acid phosphatase positivity, and bone resorption activity. The enhanced osteoclastic differentiation of CRL-2278 was accompanied by a higher rate of cells in the S/G2-M phases of cell cycle as compared to TIB-71. The analysis of nitric oxide synthase (NOS) isoforms clearly demonstrated that only neuronal NOS was detectable at high levels in CRL-2278 but not in TIB cells under all tested conditions. Moreover, the broad inhibitor of NOS activity L-NAME significantly inhibited osteoclastic differentiation of CRL-2278 cells. Altogether, these results demonstrate that a basal constitutive neuronal NOS activity positively affects the RANKL/M-CSF-related osteoclastic differentiation.

Acid Phosphatase↗

PubMed2005

Immunolocalisation of bilitranslocase in mucosecretory and parietal cells of the rat gastric mucosa.

Bilitranslocase is a plasma membrane carrier localised at the vascular pole of the rat liver cell, where it mediates uptake of organic anions from the blood into the liver. This carrier is also present in the epithelium of the rat gastric mucosa, with similar molecular mass and functional properties. An immunohistochemical study reveals that both the mucus-secreting cells of the gastric pit and the H+-secreting parietal cells express bilitranslocase. These data point to a possible role of bilitranslocase and of its food-borne substrates (anthocyanins and nicotinic acid) in regulating the function and the permeability of the gastric mucosa.

Animals↗

PubMed2004

TNF-related apoptosis-inducing ligand (TRAIL) blocks osteoclastic differentiation induced by RANKL plus M-CSF.

The role of the tumor necrosis factor (TNF) superfamily member receptor activator of nuclear factor kappa B ligand (RANKL) in promoting the differentiation of osteoclasts has been extensively characterized. In this study, we have investigated the effect of TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily of cytokines, in osteoclastogenesis, by using human peripheral blood mononuclear cells and the RAW264.7 murine monocytic cell line. Both cell models differentiate into osteoclast-like cells in presence of RANKL plus macrophage-colony-stimulating factor (M-CSF), as evaluated in terms of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and bone resorption activity. Unexpectedly, when added in culture in combination with RANKL plus M-CSF, TRAIL inhibited osteoclastic differentiation in both cell models. To investigate the molecular mechanism underlining such inhibitory activity, we analyzed the effect of TRAIL on the mitogen-activated protein kinases (MAPKs) pathways, which play a key role in osteoclastogenesis. Treatment with RANKL plus M-CSF activated both the ERK1/2 and p38/MAPK pathways, which are essential for proliferation and differentiation of preosteoclasts, respectively. Of note, the addition of TRAIL to RANKL plus M-CSF did not affect ERK1/2 but it profoundly inhibited p38/MAPK phosphorylation. Thus, our data demonstrate that TRAIL blocks osteoclastic differentiation and suggest that inhibition of the p38/MAPK pathway by TRAIL likely plays an important role in this process.

Animals↗

PubMedDate not supplied

TRAIL activates a caspase 9/7-dependent pathway in caspase 8/10-defective SK-N-SH neuroblastoma cells with two functional end points: induction of apoptosis and PGE2 release.

Most neuroblastoma cell lines do not express apical caspases 8 and 10, which play a key role in mediating tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity in a variety of malignant cell types. In this study, we demonstrated that TRAIL induced a moderate but significant increase of apoptosis in the caspase 8/10-deficient SK-N-SH neuroblastoma cell line, through activation of a novel caspase 9/7 pathway. Concomitant to the induction of apoptosis, TRAIL also promoted a significant increase of prostaglandin E2 (PGE2) release by SK-N-SH cells. Moreover, coadministration of TRAIL plus indomethacin, a pharmacological inhibitor of cyclooxygenase (COX), showed an additive effect on SK-N-SH cell death. In spite of the ability of TRAIL to promote the phosphorylation of both ERK1/2 and p38/MAPK, which have been involved in the control of COX expression/activity, neither PD98059 nor SB203580, pharmacological inhibitors of the ERK1/2 and p38/MAPK pathways, respectively, affected either PGE2 production or apoptosis induced by TRAIL. Finally, both induction of apoptosis and PGE2 release were completely abrogated by the broad caspase inhibitor z-VAD-fmk, suggesting that both biologic end points were regulated in SK-N-SH cells through a caspase 9/7-dependent pathway.

Amino Acid Chloromethyl Ketones↗

PubMedDate not supplied

Morphological observations and morphometric analysis in three human fetuses with bilateral cervical cystic hygroma.

Three human fetuses (crown-rump length, CRL, ranging from 71 to 77 mm), presenting bilateral cervical cystic hygroma were examined. The specimens were cleared and double-stained with alcian blue and alizarin red S for detecting the ossification growth patterns in the vertebral column, ribs, ischium, limbs, and face. Longitudinal measurements of some long bones in the upper (humerus, ulna, radius) and lower (femur, tibia, fibula) limb were taken. The values of both the total length (TL) and the ossified part (OL) of each long bone, as well as the OL/TL per cent ratio were considered. Reference points were located on the mandible, i.e. condylar process (Pcl), coronoid process (Pco), gnathion (GN), gonion (GO), inferior interdental point (IDI) for measuring linear dimensions. All values obtained were related with those relative to a group of fetuses, without any detectable malformation and chromosomal abnormalities, with CRL mean value 75 mm, in order to assess the presence of further anomalies, besides the cystic hygroma, in the three fetuses considered.

Anthropometry↗

PubMedDate not supplied

Immunochemical and immunocytochemical expression of protein kinase c isoenzymes alpha, delta, epsilon and zeta in primary adherent cultures of chick chondrocytes.

The family of protein kinase C (PKC) comprises serine/threonine isoenzymes involved in various biological processes, including cell proliferation and differentiation. On the bases of previous investigations performed by us on the expression of various PKC isoforms in the endochondral ossification process of the vertebral column, the aim of the present work was to investigate the expression of various PKC-isoenzymes in chick primary chondrocyte cultures i.e. the most used chondrocyte culture model in vitro. Immunochemical and immunocytochemical experiments were performed to detect the expression of PKC-alpha, -delta, -epsilon and -zeta. Chondrocyte cultures were examined two weeks after cell collection from tibiae of 6-day old chick embryos. By means of morphological observations associated with the immunocytochemical expression of type II collagen, two different cell phenotypes were identified, i.e. fibroblast-like and polygonal-roundish-shaped cells. As far as PKC-isoenzyme expression was concerned, PKC-zeta revealed a stronger immunochemical and immunocytochemical expression; PKC-alpha exhibited a positivity less marked than PKC-zeta, whereas PKC-delta and -epsilon were less expressed in this culture stage. It is reasonable that a major role could be played by PKC-alpha and -zeta in this phase of the chondrogenic process, whereas PKC-delta and -epsilon could be involved in different stages of chondrocyte differentiation in vitro.

Animals↗

PubMedDate not supplied

Expression of protein kinase C (PKC) alpha, delta, epsilon, zeta in primary chick chondrocyte cultures: immunocytochemical study.

PKC is a family of 12 serine/threonine isoenzymes that plays a pivotal role in signal transduction in a large number of biological processes. In the present work we have investigated the expression of PKC (alpha, delta, epsilon, zeta) in chick chondrocyte primary cultures at different differentiation times, i.e. at 48, 55, 62 and 69 days after cell collection from tibiae of 6-day old chick embryos. We would also detect cell differentiation stages towards the osteoblast-like cell phenotype by observing the immunocytochemical expression of the specific osteoblast marker, type I collagen. At the considered culture times, cells exhibited immunocytochemical positivity for type I collagen, thus showing their differentiation towards the osteoblast-like phenotype. PKC-zeta was the isoenzyme that exhibited the most relevant immunocytochemical expression in all considered culture times, whereas PKC-epsilon always less expressed in comparison to the other PKC-isoforms. No relevant differences were observed for the immunocytochemical expressions of PKC-alpha and PKC-delta. On the basis of the immunocytochemical data obtained from the present investigation, we could affirm that PKC-alpha, -delta, -epsilon, and -zeta may play peculiar roles in the differentiation process of chick chondrocytes towards the osteoblast-like cell phenotype.

Animals↗