Oscillations in a molecular structured cell population model

We consider a nonlinear cyclin content structured model of a cell population divided into proliferative and quiescent cells. We show, for particular values of the parameters, existence of solutions that do not depend on the cyclin content. We make numerical simulations for the general case obtaining, for some values of the parameters convergence to the steady state but also oscillations of the population for others.

The curcumin analog DM-1 induces apoptotic cell death in melanoma

The main difficulty in the successful treatment of metastatic melanoma is that this type of cancer is known to be resistant to chemotherapy. Chemotherapy remains the treatment of choice, and dacarbazine (DTIC) is the best standard treatment. The DM-1 compound is a curcumin analog that possesses several curcumin characteristics, such as antiproliferative, antitumor, and antimetastatic properties. The objective of this study was to evaluate the signaling pathways involved in melanoma cell death after treatment with DM-1 compared to the standard agent for melanoma treatment, DTIC. Cell death was evaluated by flow cytometry for annexin V and iodide propide, cleaved caspase 8, and TNF-R1 expression. Hoechst 33342 staining was evaluated by fluorescent microscopy; lipid peroxidation and cell viability (MTT) were evaluated by colorimetric assays. The antiproliferative effects of the drugs were evaluated by flow cytometry for cyclin D1 and Ki67 expression. Mice bearing B16F10 melanoma were treated with DTIC, DM-1, or both therapies. DM-1 induced significant apoptosis as indicated by the presence of cleaved caspase 8 and an increase in TNF-R1 expression in melanoma cells. Furthermore, DM-1 had antiproliferative effects in this the same cell line. DTIC caused cell death primarily by necrosis, and a smaller melanoma cell population underwent apoptosis. DTIC induced oxidative stress and several physiological changes in normal melanocytes, whereas DM-1 did not significantly affect the normal cells. DM-1 antitumor therapy in vivo showed tumor burden decrease with DM-1 monotherapy or in combination with DTIC, besides survival rate increase. Altogether, these data confirm DM-1 as a chemotherapeutic agent with effective tumor control properties and a lower incidence of side effects in normal cells compared to DTIC.

Papel de la Interleucina 6 (IL-6) en la regulación de la expresión de Osteopontina (OPN) y CD44 tras axotomía del nervio facial

Investigación producida a partir de una estancia en la University of Sidney, Australia, entre octubre del 2008 y enero del 2009. Se ha desarrollado el proyecto titulado "Papel de la interleucina 6 (IL6) en la regulación de la expresión de Osteopontina (OPN) y de CD44 tras axotomía del nervio facial". Tras efectuar una transección del nervio facial, se indujo una reactividad glial en el núcleo facial (NF) localizado en el tronco cerebral, utilizando ratones transgénicos que sobrexpresan IL6 bajo promotor GFAP (tg GFAP-IL6), es decir selectivamente en astrocitos. Se han utilizado técnicas histoquímicas e inmunohistoquímicas, así como también se ha completado el estudio utilizando análisis de RPA, western blotting y citometría de flujo para la identificación de poblaciones celulares. Los resultados obtenidos indican que la OPN se expresa constitutivamente en las neuronas del NF. Tras axotomía del nervio facial, la expresión de OPN y CD44 incrementa en los ratones WT, mientras que en los tg GFAP-IL6 disminuye significativamente, sugiriendo que la IL6 podría estar involucrada en la modulación de la expresión de ambas moléculas. Sin embargo, no se ha visto diferencias en otros receptores de OPN como la integrina Alpha-5. La ctometría de flujo corroboró algunos de los resultados histológicos sobre la reactividad microglial y permitió concluir que la proporción de microglía activada (CD11b+/CD45+mid) y macrófagos (CD11b+/CD45+high) que expresan CD44 incrementa en in los tg GFAP-IL6 versus WT donde la mayor parte de microglia activada mostraba un perfil CD11b+/CD45+low.

Extrasynaptic neurotransmission in the modulation of brain function. Focus on the striatal neuronal glial networks

Extrasynaptic neurotransmission is an important short distance form of volume transmission (VT) and describes the extracellular diffusion of transmitters and modulators after synaptic spillover or extrasynaptic release in the local circuit regions binding to and activating mainly extrasynaptic neuronal and glial receptors in the neuroglial networks of the brain. Receptor-receptor interactions in G protein-coupled receptor (GPCR) heteromers play a major role, on dendritic spines and nerve terminals including glutamate synapses, in the integrative processes of the extrasynaptic signaling. Heteromeric complexes between GPCR and ion-channel receptors play a special role in the integration of the synaptic and extrasynaptic signals. Changes in extracellular concentrations of the classical synaptic neurotransmitters glutamate and GABA found with microdialysis is likely an expression of the activity of the neuron-astrocyte unit of the brain and can be used as an index of VT-mediated actions of these two neurotransmitters in the brain. Thus, the activity of neurons may be functionally linked to the activity of astrocytes, which may release glutamate and GABA to the extracellular space where extrasynaptic glutamate and GABA receptors do exist. Wiring transmission (WT) and VT are fundamental properties of all neurons of the CNS but the balance between WT and VT varies from one nerve cell population to the other. The focus is on the striatal cellular networks, and the WT and VT and their integration via receptor heteromers are described in the GABA projection neurons, the glutamate, dopamine, 5-hydroxytryptamine (5-HT) and histamine striatal afferents, the cholinergic interneurons, and different types of GABA interneurons. In addition, the role in these networks of VT signaling of the energy-dependent modulator adenosine and of endocannabinoids mainly formed in the striatal projection neurons will be underlined to understand the communication in the striatal cellular networks

Targeting microglial KATP channels to treat neurodegenerative diseases: a mitochondrial issue

Neurodegeneration is a complex process involving different cell types and neurotransmitters. A common characteristic of neurodegenerative disorders is the occurrence of a neuroinflammatory reaction in which cellular processes involving glial cells, mainly microglia and astrocytes, are activated in response to neuronal death. Microglia do not constitute a unique cell population but rather present a range of phenotypes closely related to the evolution of neurodegeneration. In a dynamic equilibrium with the lesion microenvironment, microglia phenotypes cover from a proinflammatory activation state to a neurotrophic one directly involved in cell repair and extracellular matrix remodeling. At each moment, the microglial phenotype is likely to depend on the diversity of signals from the environment and of its response capacity. As a consequence, microglia present a high energy demand, for which the mitochondria activity determines the microglia participation in the neurodegenerative process. As such, modulation of microglia activity by controlling microglia mitochondrial activity constitutes an innovative approach to interfere in the neurodegenerative process. In this review, we discuss the mitochondrial KATP channel as a new target to control microglia activity, avoid its toxic phenotype, and facilitate a positive disease outcome.

Targeting microglial KATP channels to treat neurodegenerative diseases: a mitochondrial issue

Neurodegeneration is a complex process involving different cell types and neurotransmitters. A common characteristic of neurodegenerative disorders is the occurrence of a neuroinflammatory reaction in which cellular processes involving glial cells, mainly microglia and astrocytes, are activated in response to neuronal death. Microglia do not constitute a unique cell population but rather present a range of phenotypes closely related to the evolution of neurodegeneration. In a dynamic equilibrium with the lesion microenvironment, microglia phenotypes cover from a proinflammatory activation state to a neurotrophic one directly involved in cell repair and extracellular matrix remodeling. At each moment, the microglial phenotype is likely to depend on the diversity of signals from the environment and of its response capacity. As a consequence, microglia present a high energy demand, for which the mitochondria activity determines the microglia participation in the neurodegenerative process. As such, modulation of microglia activity by controlling microglia mitochondrial activity constitutes an innovative approach to interfere in the neurodegenerative process. In this review, we discuss the mitochondrial KATP channel as a new target to control microglia activity, avoid its toxic phenotype, and facilitate a positive disease outcome.

Historical first descriptions of Cajal-Retzius cells: from pioneer studies to current knowledge

Santiago Ramón y Cajal developed a great body of scientific research during the last decade of 19th century, mainly between 1888 and 1892, when he published more than 30 manuscripts. The neuronal theory, the structure of dendrites and spines, and fine microscopic descriptions of numerous neural circuits are among these studies. In addition, numerous cell types (neuronal and glial) were described by Ramón y Cajal during this time using this 'reazione nera' or Golgi method. Among these neurons were the special cells of the molecular layer of the neocortex. These cells were also termed Cajal cells or Retzius cells by other colleagues. Today these cells are known as Cajal-Retzius cells. From the earliest description, several biological aspects of these fascinating cells have been analyzed (e.g., cell morphology, physiological properties, origin and cellular fate, putative function during cortical development, etc). In this review we will summarize in a temporal basis the emerging knowledge concerning this cell population with specific attention the pioneer studies of Santiago Ramón y Cajal.

Planarians as a model to assess in vivo the role of matrix metalloproteinase genes during homeostasis and regeneration

Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results have high potential to generate significant information for development of regenerative and anti cancer therapies.

ALK rearrangement in a selected population of advanced non small cell lung cancer patients. FISH and inmunohistochemistry diagnostic methods, prevalence and clinical outcomes

Anaplastic lymphoma kinase (ALK) rearrangements represents a new driver oncogenic event in non-small cell lung cancer (NSCLC). ALK positive patients account for a 1-7% of NSCLC patients. The objective of this study is to know the prevalence and clinical characteristics of ALK positive patients in a cohort of NSCLC patients and to compare inmunohistochemistry with D5F3 monoclonal antibody with gold standard method fluorescence in situ hybridation

A pioneering epidemiological study investigating the incidence of squamous cell carcinoma of tongue in a Portuguese population

Objective: The purpose of this study was to investigate the incidence of squamous cell carcinoma (SCC) of the anterior two thirds of the tongue in a population living in central and southern Portugal, all treated at Instituto Português de Oncologia de Lisboa, Francisco Gentil (IPOLFG). Study Design: This study was a retrospective review of all patients who had a histopathological diagnosis of SCC of the anterior two thirds of the tongue and had been treated in the Head and Neck Surgery Unit at the IPOLFG (Lisbon, Portugal), between 1st January 2001 and 31st December 2009. The risk factors evaluated were: gender; age; alcohol consumption; tobacco use; prosthesis use and the carcinoma site. Results: Of the 424 cases analysed, 71% were men. Mean age of occurrence was in 5th decade for males and the 6th decade for females, and the border of the tongue was the most common location. Alcohol consumption and tobacco had a lower impact in women, being the most common aetiological factors in the male population. No significant association was observed between patients and the use of a prosthesis. Conclusions: In spite of the consumption of aohol and tobacco starting to decline in certain parts of the world, our findings showed both factors still have a significant impact in male population. Further research should be done to determine aetiological factors in females.

Oral tongue squamous cell carcinoma (OTSCC): alcohol and tobacco consumption versus non-consumption. A study in a Portuguese population

There has been an increase in the incidence of carcinoma of the tongue, particularly among alcohol and tobacco non-users. However, the number of studies that would allow a better understanding of etiological factors and clinical features, particularly in the Portuguese population, is very limited. This study was based on patients with squamous cell carcinoma of the anterior two thirds of the tongue that were treated at the Department of Head and Neck Surgery of the ¿Instituto Portugues de Oncologia de Lisboa - Francisco Gentil" IPOLFG) in Lisbon, Portugal, between January 1, 2001 and December 31, 2009. The patients were divided in alcohol and tobacco users and non-users in order to evaluate the differences between these 2 groups based on gender, age, tumor location, denture use, and tumor size, metastasis and stage. Of the 354 cases, 208 were users and 146 were non-users. The main location in both groups was the lateral border of the tongue. Denture use showed no significant effect in both study groups. It was possible to conclude that patients who did not drink or smoke were older and presented with smaller tumor size, lower incidence of ganglion metastasis and lower tumor stage compared with alcohol and tobacco users.

Micropatterning of single endothelial cell shape reveals a tight coupling between nuclear volume in G1 and proliferation

Shape-dependent local differentials in cell proliferation are considered to be a major driving mechanism of structuring processes in vivo, such as embryogenesis, wound healing, and angiogenesis. However, the specific biophysical signaling by which changes in cell shape contribute to cell cycle regulation remains poorly understood. Here, we describe our study of the roles of nuclear volume and cytoskeletal mechanics in mediating shape control of proliferation in single endothelial cells. Micropatterned adhesive islands were used to independently control cell spreading and elongation. We show that, irrespective of elongation, nuclear volume and apparent chromatin decondensation of cells in G1 systematically increased with cell spreading and highly correlated with DNA synthesis (percent of cells in the S phase). In contrast, cell elongation dramatically affected the organization of the actin cytoskeleton, markedly reduced both cytoskeletal stiffness (measured dorsally with atomic force microscopy) and contractility (measured ventrally with traction microscopy), and increased mechanical anisotropy, without affecting either DNA synthesis or nuclear volume. Our results reveal that the nuclear volume in G1 is predictive of the proliferative status of single endothelial cells within a population, whereas cell stiffness and contractility are not. These findings show that the effects of cell mechanics in shape control of proliferation are far more complex than a linear or straightforward relationship. Our data are consistent with a mechanism by which spreading of cells in G1 partially enhances proliferation by inducing nuclear swelling and decreasing chromatin condensation, thereby rendering DNA more accessible to the replication machinery.

Determinants of the omega-3 index in a Mediterranean population at increased risk for CHD.

The omega-3 index, defined as the sum of EPA and DHA in erythrocyte membranes expressed as a percentage of total fatty acids, has been proposed as both a risk marker and risk factor for CHD death. A major determinant of the omega-3 index is EPA þ DHA intake, but the impact of other dietary fatty acids has not been investigated. In a cross-sectional study on 198 subjects (102 men and 96 women, mean age 66 years) at high cardiovascular risk living in Spain, the country with low rates of cardiac death despite a high prevalence of cardiovascular risk factors, dietary data were acquired from FFQ and blood cell membrane fatty acid composition was measured by GC. The average consumption of EPA þ DHA was 0·9 g/d and the mean omega-3 index was 7·1%. In multivariate models, EPA þ DHA intake was the main predictor of the omega-3 index but explained only 12% of its variability (P,0·001). No associations with other dietary fatty acids were observed. Although the single most influential determinant of the omega-3 index measured here was the intake of EPA þ DHA, it explained little of the former"s variability; hence, the effects of other factors (genetic, dietary and lifestyle) remain to be determined. Nevertheless, the high omega-3 index could at least partially explain the paradox of low rates of fatal CHD in Spain despite a high background prevalence of cardiovascular risk factors.

Determinants of the omega-3 index in a Mediterranean population at increased risk for CHD.

The omega-3 index, defined as the sum of EPA and DHA in erythrocyte membranes expressed as a percentage of total fatty acids, has been proposed as both a risk marker and risk factor for CHD death. A major determinant of the omega-3 index is EPA þ DHA intake, but the impact of other dietary fatty acids has not been investigated. In a cross-sectional study on 198 subjects (102 men and 96 women, mean age 66 years) at high cardiovascular risk living in Spain, the country with low rates of cardiac death despite a high prevalence of cardiovascular risk factors, dietary data were acquired from FFQ and blood cell membrane fatty acid composition was measured by GC. The average consumption of EPA þ DHA was 0·9 g/d and the mean omega-3 index was 7·1%. In multivariate models, EPA þ DHA intake was the main predictor of the omega-3 index but explained only 12% of its variability (P,0·001). No associations with other dietary fatty acids were observed. Although the single most influential determinant of the omega-3 index measured here was the intake of EPA þ DHA, it explained little of the former"s variability; hence, the effects of other factors (genetic, dietary and lifestyle) remain to be determined. Nevertheless, the high omega-3 index could at least partially explain the paradox of low rates of fatal CHD in Spain despite a high background prevalence of cardiovascular risk factors.

Determinants of the omega-3 index in a Mediterranean population at increased risk for CHD.

The omega-3 index, defined as the sum of EPA and DHA in erythrocyte membranes expressed as a percentage of total fatty acids, has been proposed as both a risk marker and risk factor for CHD death. A major determinant of the omega-3 index is EPA þ DHA intake, but the impact of other dietary fatty acids has not been investigated. In a cross-sectional study on 198 subjects (102 men and 96 women, mean age 66 years) at high cardiovascular risk living in Spain, the country with low rates of cardiac death despite a high prevalence of cardiovascular risk factors, dietary data were acquired from FFQ and blood cell membrane fatty acid composition was measured by GC. The average consumption of EPA þ DHA was 0·9 g/d and the mean omega-3 index was 7·1%. In multivariate models, EPA þ DHA intake was the main predictor of the omega-3 index but explained only 12% of its variability (P,0·001). No associations with other dietary fatty acids were observed. Although the single most influential determinant of the omega-3 index measured here was the intake of EPA þ DHA, it explained little of the former"s variability; hence, the effects of other factors (genetic, dietary and lifestyle) remain to be determined. Nevertheless, the high omega-3 index could at least partially explain the paradox of low rates of fatal CHD in Spain despite a high background prevalence of cardiovascular risk factors.