Children's Physical Activity During the COVID-19 Lockdown: A Cross Cultural Comparison Between Portugal, Brazil and Italy

The COVID-19 pandemic forced governments to implement measures that disrupted the daily routines of many families worldwide. We studied how the COVID-19 lockdown affected children's routines in Portugal (PT), Brazil (BR), and Italy (IT) to determine if children's age and country impacted their physical activity (PA) and sedentary time. We launched an anonymous online survey to assess how 3-12 years old children adjusted their daily routines to this situation. Parents reported the times each child was engaged in different activities throughout the day, and we used these data to calculate separately overall sedentary and physical activity time. We conducted separate analyses of variance for age and country on the percentage of time spent in the different activities. Results, based on the data from 3045 children in these three countries (PT n = 2044; BR n = 836; IT n = 165), showed that, during lockdown, most children spent most of their awake daily hours in sedentary activities. There was a clear age effect on the way their routines were organized. Percentages of time spent in intellectual activity, playful screen activity, and overall sedentary time were greater in the older age groups, whereas percentages of time spent in play (with and without PA) and in overall PA were greater in the younger groups. We found a main effect of country for all variables except play without PA. The country effect was mainly due to the difference between the routines in BR when compared to PT and IT. Values of playful screen time and overall sedentary activity were higher in BR than in the two European countries. Conversely, values for play with PA, PA, and overall PA (except in the older group) were lower in BR. Patterns of time spent in these activities were similar in IT and PT, but PA and overall PA times were higher in the two younger age groups in IT. In summary, percentage of PA time of confined children was low and decreased with age across all three countries and was particularly low for children in BR relative to those in PT and IT.

Plasma microglial-derived extracellular vesicles are increased in frail patients with Mild Cognitive Impairment and exert a neurotoxic effect

Extracellular vesicles (EVs) are mediators of cellular communication that can be released by almost all cell types in both physiological and pathological conditions and are present in most biological fluids. Such characteristics make them attractive in the research of biomarkers for age-related pathological conditions. Based on this, the aim of the present study was to examine the changes in EV concentration and size in the context of frailty, a geriatric syndrome associated with a progressive physical and cognitive decline. Specifically, total EVs and neural and microglial-derived EVs (NDVs and MDVs respectively) were investigated in plasma of frail and non-frail controls (CTRL), mild cognitive impairment (MCI) subjects, and in Alzheimer's disease (AD) patients. Results provided evidence that AD patients displayed diminished NDV concentration (3.61 × 10⁹ ± 1.92 × 10⁹ vs 7.16 × 10⁹ ± 4.3 × 10⁹ particles/ml) and showed high diagnostic performance. They are able to discriminate between AD and CTRL with an area under the curve of 0.80, a sensitivity of 78.95% and a specificity of 85.7%, considering the cut-off of 5.27 × 10⁹ particles/ml. Importantly, we also found that MDV concentration was increased in frail MCI patients compared to CTRL (5.89 × 10⁹ ± 3.98 × 10⁹ vs 3.16 × 10⁹ ± 3.04 × 10⁹ particles/ml, P < 0.05) and showed high neurotoxic effect on neurons. MDV concentration discriminate frail MCI vs non-frail CTRL (AUC = 0.76) with a sensitivity of 80% and a specificity of 70%, considering the cut-off of 2.69 × 10⁹ particles/ml. Altogether, these results demonstrated an alteration in NDV and MDV release during cognitive decline, providing important insight into the role of EVs in frailty status.

Learning to Cycle: A Cross-Cultural and Cross-Generational Comparison

Background

Learning to cycle is an important milestone for children, but the popularity of cycling and the environmental factors that promote the development and practice of this foundational movement skill vary among cultures and across time. This present study aimed to investigate if country of residence and the generation in which a person was born influence the age at which people learn to cycle.

Methods

Data were collected through an online survey between November 2019 and December 2020. For this study, a total of 9,589 responses were obtained for adults (self-report) and children (parental report) living in 10 countries (Portugal, Italy, Brazil, Finland, Spain, Belgium, United Kingdom, Mexico, Croatia, and the Netherlands). Participants were grouped according to their year of birth with 20-year periods approximately corresponding to 3 generations: 1960-79 (generation X; n = 2,214); 1980-99 (generation Y; n = 3,994); 2000-2019 (generation Z; n = 3,381).

Results

A two-way ANOVA showed a significant effect of country, F _(9,8628) = 90.17, p < 0.001, η p 2 = 0.086, and generation, F _(2,8628) = 47.21, p < 0.001, η p 2 = 0.122, on the age at which individuals learn to cycle. Countries with the lowest learning age were the Netherlands, Finland and Belgium and countries with the highest learning age were Brazil and Mexico. Furthermore, the age at which one learns to cycle has decreased across generations. There was also a significant country x generation interaction effect on learning age, F _(18,8628) = 2.90, p < 0.001; however, this effect was negligible ( η p 2 = 0.006).

Conclusions

These findings support the socio-ecological perspective that learning to cycle is a process affected by both proximal and distal influences, including individual, environment and time.

Therapeutic Induction of Energy Metabolism Reduces Neural Tissue Damage and Increases Microglia Activation in Severe Spinal Cord Injury

Neural tissue has high metabolic requirements. Following spinal cord injury (SCI), the damaged, tissue suffers from a severe metabolic impairment, which aggravates axonal degeneration and, neuronal loss. Impaired cellular energetic, tricarboxylic acid (TCA) cycle and oxidative, phosphorylation metabolism in neuronal cells has been demonstrated to be a major cause of neural tissue death and regeneration failure following SCI. Therefore, rewiring the spinal cord cell metabolism may be an innovative therapeutic strategy for the treatment of SCI. In this study, we evaluated the therapeutic effect of the recovery of oxidative metabolism in a mouse model of severe contusive SCI. Oral administration of TCA cycle intermediates, co-factors, essential amino acids, and branched-chain amino acids was started 3 days post-injury and continued until the end of the experimental procedures. Metabolomic, immunohistological, and biochemical analyses were performed on the injured spinal cord sections. Administration of metabolic precursors enhanced spinal cord oxidative metabolism. In line with this metabolic shift, we observed the activation of the mTORC1 anabolic pathway, the increase in mitochondrial mass, and ROS defense which effectively prevented the injury-induced neural cell apoptosis in treated animals. Consistently, we found more choline acetyltransferase (ChAT)-expressing motor neurons and increased neurofilament positive corticospinal axons in the spinal cord parenchyma of the treated mice. Interestingly, oral administration of the metabolic precursors increased the number of activated microglia expressing the CD206 marker suggestive of a, pro-resolutive, M2-like phenotype. These molecular and histological modifications observed in treated animals ultimately led to a significant, although partial, improvement of the motor functions. Our data demonstrate that rewiring the cellular metabolism can represent an effective strategy to treat SCI.

Murine cerebral organoids develop network of functional neurons and hippocampal brain region identity

Brain organoids are in vitro three-dimensional (3D) self-organized neural structures, which can enable disease modeling and drug screening. However, their use for standardized large-scale drug screening studies is limited by their high batch-to-batch variability, long differentiation time (10-20 weeks), and high production costs. This is particularly relevant when brain organoids are obtained from human induced pluripotent stem cells (iPSCs). Here, we developed, for the first time, a highly standardized, reproducible, and fast (5 weeks) murine brain organoid model starting from embryonic neural stem cells. We obtained brain organoids, which progressively differentiated and self-organized into 3D networks of functional neurons with dorsal forebrain phenotype. Furthermore, by adding the morphogen WNT3a, we generated brain organoids with specific hippocampal region identity. Overall, our results showed the establishment of a fast, robust and reproducible murine 3D in vitro brain model that may represent a useful tool for high-throughput drug screening and disease modeling.

Meninges: A Widespread Niche of Neural Progenitors for the Brain

Emerging evidence highlights the several roles that meninges play in relevant brain functions as they are a protective membrane for the brain, produce and release several trophic factors important for neural cell migration and survival, control cerebrospinal fluid dynamics, and embrace numerous immune interactions affecting neural parenchymal functions. Furthermore, different groups have identified subsets of neural progenitors residing in the meninges during development and in the adulthood in different mammalian species, including humans. Interestingly, these immature neural cells are able to migrate from the meninges to the neural parenchyma and differentiate into functional cortical neurons or oligodendrocytes. Immature neural cells residing in the meninges promptly react to brain disease. Injury-induced expansion and migration of meningeal neural progenitors have been observed following experimental demyelination, traumatic spinal cord and brain injury, amygdala lesion, stroke, and progressive ataxia. In this review, we summarize data on the function of meninges as stem cell niche and on the presence of immature neural cells in the meninges, and discuss their roles in brain health and disease. Furthermore, we consider the potential exploitation of meningeal neural progenitors for the regenerative medicine to treat neurological disorders.

Fingolimod Plays Role in Attenuation of Myocardial Injury Related to Experimental Model of Cardiac Arrest and Extracorporeal Life Support Resuscitation

Background: Sudden cardiac arrest is a major global health concern, and survival of patients with ischemia–reperfusion injury is a leading cause of myocardial dysfunction. The mechanism of this phenomenon is not well understood because of the complex pathophysiological nature of the disease. Aim of the study was to investigate the cardioprotective role of fingolimod in an in vivo model of cardiac arrest and resuscitation. Methods: In this study, an in vivo rat model of cardiac arrest using extracorporeal membrane oxygenation resuscitation monitored by invasive hemodynamic measurement was developed. At the beginning of extracorporeal life support (ECLS), animals were randomly treated with fingolimod (Group A, n = 30) or saline (Group B, n = 30). Half of the animals in each group (Group A1 and B1, n = 15 each) were sacrificed after 1 h, and the remaining animals (Group A2 and B2) after 24 h of reperfusion. Blood and myocardial tissues were collected for analysis of cardiac features, inflammatory biomarkers, and cell signaling pathways. Results: Treatment with fingolimod resulted in activation of survival pathways resulting into reduced inflammation, myocardial oxidative stress and apoptosis of cardiomyocytes. This led to significant improvement in systolic and diastolic functions of the left ventricle and improved contractility index. Conclusions: Sphingosine1phosphate receptor activation with fingolimod improved cardiac function after cardiac arrest supported with ECLS. Present study findings strongly support a cardioprotective role of fingolimod through sphingosine-1-phosphate receptor activation during reperfusion after circulatory arrest.

Neuroendocrine Effects of Subcutaneous Interleukin-2 Injection in Cancer Patients

Intravenous interleukin-2 (IL-2) administration has been shown to influence several hormonal secretions. The present study was carried out to investigate the endocrine effects of subcutaneous therapy with IL-2. Six patients with advanced renal cancer were studied. They were treated subcutaneously with IL-2 according to the schedule proposed by Atzpodien et al. Venous blood samples were collected at O-time and 1, 8 and 12 hours after the first IL-2 pulse of 9 × 106 IU/m2 at 8.00 a.m.; on a separate occasion, samples were collected during a saline infusion only. In each blood sample, serum levels of Cortisol, β-endorphin, GH, PRL, FSH, LH, TSH and the pineal hormone melatonin were measured by RIA. Both Cortisol and β-endorphin significantly increased after IL-2 injection. GH rose but not to a significant extent. PRL, FSH, LH and TSH did not change after IL-2. Finally, melatonin levels markedly decreased after IL-2 injection in the only 2 patients with elevated concentrations of this hormone before the start of immunotherapy. These results suggest that the endocrine effects of subcutaneous IL-2 therapy are similar to those previously described with intravenous administration.

Endocrinological Study of the Dopaminergic Regulation of Prolactin Release in Metastatic Breast Cancer

Aims and Background

Prolactin (PRL) may be a growth factor for breast cancer. Abnormally high levels of PRL have been proven to be associated with a poor prognosis in metastatic breast cancer. However, most studies have been limited to the evaluation of basal levels of PRL rather than its response to the classical endocrine dynamic tests. This study was performed to analyse the dynamic secretion of PRL under stimulatory and inhibitory tests in metastatic breast cancer.

Methods

The study included 10 untreated metastatic breast cancer women, who were evaluated after the classical stimulatory and inhibitory tests for PRL secretion with the antidopaminergic agent Metoclopramide (10 mg iv as a bolus) and with L-dopa, respectively. Serum levels of PRL were measured by RIA before and at subsequent intervals after drug administration. PRL levels were considered to be elevated when they were higher than 25 ng/ml.

Results

Abnormally high basal levels of PRL were seen in 6/10 patients. L-dopa was unable to inhibit PRL secretion, whose mean concentrations paradoxically significantly increased in response to L-dopa, with values comparable to those observed after the classical stimulatory test with metoclopramide.

Conclusions

This study confirm the existence of hyperprolactinemia associated with metastatic breast cancer. In addition, by showing a paradoxical rise of PRL in response to L-dopa, which inhibits PRL secretion in physiological conditions, this study would suggest that breast cancer-related hyperprolactinemia may depend at least in part on endogenous disease-related neuroendocrine alterations.

Prolactin Response to Thyrotropin-Releasing Hormone in Early and Advanced Human Breast Cancer

While prolactin (PRL) has been shown to stimulate the development of mammary carcinoma in several animal species, its role in human breast cancer remains to be established. To further investigate PRL secretion in human breast cancer, its basal levels and response to thyrotropin-releasing hormone (TRH) were evaluated in 16 patients (6 with no metastases and 10 with metastatic locations). The control group consisted of 19 healthy women. High PRL basal concentrations were seen in 2 patients only; no significant differences were found between the other patients and the normal subjects. The PRL increase induced by TRH administration was significantly higher in patients than in controls. Finally a change in the hormonal secretion was found after chemotherapy in 3 of the 5 patients in whom PRL response to TRH was evaluated either before or 10-12 days after a cycle of intravenous CMF adjuvant chemotherapy. These results demonstrate the existence of an exaggerated response of PRL to TRH in patients with breast cancer, even in the presence of normal basal levels. Moreover, they would seem to suggest a possible influence of CMF on PRL response to TRH stimulation.

Increased Level of Soluble Interleukin-2 Receptor in Advanced Solid Tumors: A Preliminary Study

Both activated normal and transformed lymphocytes produce not only cell-associated but also cell-free IL-2R. Evidence of high serum concentrations of IL-2R appears to serve as a tumor marker in patients with lymphomas On the contrary, the role of soluble IL-2R in solid neoplasms has still to be defined. This investigation was carried out to analyze soluble IL-2R production in human solid tumors. The study included 35 patients with solid tumors (12 without and 23 with metastases), 58 healthy subjects and 6 lymphoma patients. Among cancer patients, lung and breast carcinoma were the two most frequent neoplasms. In each subject or patient, serum levels of IL-2R were measured by using an enzyme immunoassay. Moreover, in 14/23 patients with metastatic solid tumors, lymphocyte subpopulations were also evaluated. Serum levels of IL-2R were significantly higher in the cancer patients than in the normal subjects. The patients with metastatic solid tumors showed significantly higher mean levels than those without metastases, and similar to those observed in the lymphoma patients. Finally, there was no correlation between serum levels of IL-2R and the T4/T8 ratio, which was reduced in 5/14 cancer patients. Further studies will be needed to establish if elevated concentrations of IL-2R in the serum can contribute to the immunoincompetence of patients with disseminated solid neoplasms.

Neuroimmunomodulation in Cancer Patients: Correlations between Melatonin and ß-Endorphin Blood Levels and T Helper/Suppressor Ratio

The pineal gland and opioid peptides play roles in the neuroendocrine control of immunity. Both neuroendocrine and immune dysfunctions have been observed in cancer but the importance of the altered secretion of neurohormones in the immunoincompetence of cancer patients has never been investigated. This study concomitantly evaluated neuroendocrine and immune functions in 40 patients with early or advanced neoplastic disease. In each patient, melatonin and β-endorphin blood levels and lymphocyte subtypes were determined on venous blood samples collected during the morning. Metastatic patients had lower melatonin levels and a lower T4/T8 ratio than patients without metastases but no significant correlation was found between melatonin and the T4/T8 ratio. β-endorphin levels appeared to be normal in all patients. These results suggest that melatonin and β-endorphin secretion have no role in determining immune dysfunctions in cancer.

Acute Effects of Various Chemotherapeutic Combinations on Hypophyseal and Pineal Hormone Secretions in Cancer Patients

It is known that prolonged therapy with cytotoxic drugs may affect the endocrine system. The present study was carried out to establish whether administration of chemotherapeutic drugs acutely influences hypophyseal and pineal activities. Nineteen patients affected by solid tumors were included in the study, 5 of whom were treated with CMF, 4 with FEC, 4 with CEV, and 6 with CDDP. Cytotoxic drugs were intravenously administered. Venous blood samples were collected at zero time and at 30, 60, 120 and 180 min after drug administration. On a separate occasion, venous blood samples were drawn during a saline infusion only. In each sample FSH, LH, GH, PRL, TSH, Cortisol, melatonin and β-endorphin were determined by the RIA method. The only significant changes observed in this study were a rise in PRL and a decrease in β-endorphin after CDDP administration. Melatonin was enhanced after CDDP and CMF, and Cortisol decreased after CMF and FEC, but their variations were not statistically significant with respect to those seen during saline infusion.

A New Chemical Etching Process to Improve Endosseous Implant Osseointegration: In Vitro Evaluation on Human Osteoblast-Like Cells

The development of novel mechanical and chemical surface modification treatments to improve the osteointegration properties of osseointegrated dental implants is nowadays a topic of great applicative interest. The aim of the present study was to analyse the role of surface topography and chemistry of four different surface treatments on titanium by an in vitro human osteosarcoma immortalised cell line model (MG63). The surface treatments considered were (a) machined titanium, (b) chemical etched on machined titanium, (c) sandblasted titanium and (d) chemical etching on sandblasted titanium.

Chemical and physical surface properties were investigated by Scanning Electron Microscopy, Thin Film-X ray Diffraction and by Laser Profilometry. The in vitro biological response was characterised using the MG63 cell line by elution cytotoxicity tests, cell morphology, adhesion, proliferation activity, alkaline phosphatase activity and total DNA content in order to show a relationship between osteoblast response and surface features.

Chemical and physical characterisation showed that the considered treatments differently modify the surface morphology in the micro and sub-micrometric scale. Although some differences in alkaline phosphatase activity were observed in the biological characterisation, depending on the specific material's surface finishing, the results showed that cells were well responsive on all the tested materials and grew and differentiated with similar proliferation rate.

Psychedelics and reconsolidation of traumatic and appetitive maladaptive memories: focus on cannabinoids and ketamine

RATIONALE

Clinical data with 3,4-methylenedioxymethamphetamine (MDMA) in post-traumatic stress disorder (PTSD) patients recently stimulated interest on the potential therapeutic use of psychedelics in disorders characterized by maladaptive memories, including substance use disorders (SUD). The rationale for the use of MDMA in PTSD and SUD is being extended to a broader beneficial "psychedelic effect," which is supporting further clinical investigations, in spite of the lack of mechanistic hypothesis. Considering that the retrieval of emotional memories reactivates specific brain mechanisms vulnerable to inhibition, interference, or strengthening (i.e., the reconsolidation process), it was proposed that the ability to retrieve and change these maladaptive memories might be a novel intervention for PTSD and SUD. The mechanisms underlying MDMA effects indicate memory reconsolidation modulation as a hypothetical process underlying its efficacy.

OBJECTIVE

Mechanistic and clinical studies with other two classes of psychedelic substances, namely cannabinoids and ketamine, are providing data in support of a potential use in PTSD and SUD based on the modulation of traumatic and appetitive memory reconsolidation, respectively. Here, we review preclinical and clinical data on cannabinoids and ketamine effects on biobehavioral processes related to the reconsolidation of maladaptive memories.

RESULTS

We report the findings supporting (or not) the working hypothesis linking the potential therapeutic effect of these substances to the underlying reconsolidation process. We also proposed possible approaches for testing the use of these two classes of drugs within the current paradigm of reconsolidation memory inhibition.

CONCLUSIONS

Metaplasticity may be the process in common between cannabinoids and ketamine/ketamine-like substance effects on the mediation and potential manipulation of maladaptive memories.

High Yield of Adult Oligodendrocyte Lineage Cells Obtained from Meningeal Biopsy

Oligodendrocyte loss can lead to cognitive and motor deficits. Current remyelinating therapeutic strategies imply either modulation of endogenous oligodendrocyte precursors or transplantation of in vitro expanded oligodendrocytes. Cell therapy, however, still lacks identification of an adequate source of oligodendrocyte present in adulthood and able to efficiently produce transplantable cells. Recently, a neural stem cell-like population has been identified in meninges. We developed a protocol to obtain high yield of oligodendrocyte lineage cells from one single biopsy of adult rat meningeal tissue. From 1 cm2 of adult rat spinal cord meninges, we efficiently expanded a homogenous culture of 10 millions of meningeal-derived oligodendrocyte lineage cells in a short period of time (approximately 4 weeks). Meningeal-derived oligodendrocyte lineage cells show typical mature oligodendrocyte morphology and express specific oligodendrocyte markers, such as galactosylceramidase and myelin basic protein. Moreover, when transplanted in a chemically demyelinated spinal cord model, meningeal-derived oligodendrocyte lineage cells display in vivo-remyelinating potential. This oligodendrocyte lineage cell population derives from an accessible and adult source, being therefore a promising candidate for autologous cell therapy of demyelinating diseases. In addition, the described method to differentiate meningeal-derived neural stem cells into oligodendrocyte lineage cells may represent a valid in vitro model to dissect oligodendrocyte differentiation and to screen for drugs capable to promote oligodendrocyte regeneration.

Amino acid supplements and metabolic health: a potential interplay between intestinal microbiota and systems control

Dietary supplementation of essential amino acids (EAAs) has been shown to promote healthspan. EAAs regulate, in fact, glucose and lipid metabolism and energy balance, increase mitochondrial biogenesis, and maintain immune homeostasis. Basic science and epidemiological results indicate that dietary macronutrient composition affects healthspan through multiple and integrated mechanisms, and their effects are closely related to the metabolic status to which they act. In particular, EAA supplementation can trigger different and even opposite effects depending on the catabolic and anabolic states of the organisms. Among others, gut-associated microbial communities (referred to as gut microbiota) emerged as a major regulator of the host metabolism. Diet and host health influence gut microbiota, and composition of gut microbiota, in turn, controls many aspects of host health, including nutrient metabolism, resistance to infection, and immune signals. Altered communication between the innate immune system and the gut microbiota might contribute to complex diseases. Furthermore, gut microbiota and its impact to host health change largely during different life phases such as lactation, weaning, and aging. Here we will review the accumulating body of knowledge on the impact of dietary EAA supplementation on the host metabolic health and healthspan from a holistic perspective. Moreover, we will focus on the current efforts to establish causal relationships among dietary EAAs, gut microbiota, and health during human development.

Sphingosine 1-Phosphate Receptor Modulator Fingolimod (FTY720) Attenuates Myocardial Fibrosis in Post-heterotopic Heart Transplantation

Background and Objective: Sphingosine 1-phosphate (S1P), and S1P receptor modulator fingolimod have been suggested to play important cardioprotective role in animal models of myocardial ischemia/reperfusion injuries. To understand the cardioprotective function of S1P and its mechanism in vivo, we analyzed apoptotic, inflammatory biomarkers, and myocardial fibrosis in an in vivo heterotopic rat heart transplantation model.

Methods: Heterotopic heart transplantation is performed in 60 Sprague–Dawley (SD) rats (350–400 g). The heart transplant recipients (n = 60) are categorized into Group A (control) and Group B (fingolimod treated 1 mg/kg intravenous). At baseline with 24 h after heart transplantation, blood and myocardial tissue are collected for analysis of myocardial biomarkers, apoptosis, inflammatory markers, oxidative stress, and phosphorylation of Akt/Erk/STAT-3 signaling pathways. Myocardial fibrosis was investigated using Masson’s trichrome staining and L-hydroxyline.

Results: Fingolimod treatment activates both Reperfusion Injury Salvage Kinase (RISK) and Survivor Activating Factor Enhancement (SAFE) pathways as evident from activation of anti-apoptotic and anti-inflammatory pathways. Fingolimod treatment caused a reduction in myocardial oxidative stress and hence cardiomyocyte apoptosis resulting in a decrease in myocardial reperfusion injury. Moreover, a significant (p < 0.001) reduction in collagen staining and hydroxyproline content was observed in fingolimod treated animals 30 days after transplantation demonstrating a reduction in cardiac fibrosis.

Conclusion: S1P receptor activation with fingolimod activates anti-apoptotic and anti-inflammatory pathways, leading to improved myocardial salvage causing a reduction in cardiac fibrosis.

New neurons in adult brain: distribution, molecular mechanisms and therapies

"Are new neurons added in the adult mammalian brain?" "Do neural stem cells activate following CNS diseases?" "How can we modulate their activation to promote recovery?" Recent findings in the field provide novel insights for addressing these questions from a new perspective. In this review, we will summarize the current knowledge about adult neurogenesis and neural stem cell niches in healthy and pathological conditions. We will first overview the milestones that have led to the discovery of the classical ventricular and hippocampal neural stem cell niches. In adult brain, new neurons originate from proliferating neural precursors located in the subventricular zone of the lateral ventricles and in the subgranular zone of the hippocampus. However, recent findings suggest that new neuronal cells can be added to the adult brain by direct differentiation (e.g., without cell proliferation) from either quiescent neural precursors or non-neuronal cells undergoing conversion or reprogramming to neuronal fate. Accordingly, in this review we will also address critical aspects of the newly described mechanisms of quiescence and direct conversion as well as the more canonical activation of the neurogenic niches and neuroblast reservoirs in pathological conditions. Finally, we will outline the critical elements involved in neural progenitor proliferation, neuroblast migration and differentiation and discuss their potential as targets for the development of novel therapeutic drugs for neurodegenerative diseases.

Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground

This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s) appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens.

Meninges harbor cells expressing neural precursor markers during development and adulthood

Brain and skull developments are tightly synchronized, allowing the cranial bones to dynamically adapt to the brain shape. At the brain-skull interface, meninges produce the trophic signals necessary for normal corticogenesis and bone development. Meninges harbor different cell populations, including cells forming the endosteum of the cranial vault. Recently, we and other groups have described the presence in meninges of a cell population endowed with neural differentiation potential in vitro and, after transplantation, in vivo. However, whether meninges may be a niche for neural progenitor cells during embryonic development and in adulthood remains to be determined. In this work we provide the first description of the distribution of neural precursor markers in rat meninges during development up to adulthood. We conclude that meninges share common properties with the classical neural stem cell niche, as they: (i) are a highly proliferating tissue; (ii) host cells expressing neural precursor markers such as nestin, vimentin, Sox2 and doublecortin; and (iii) are enriched in extracellular matrix components (e.g., fractones) known to bind and concentrate growth factors. This study underlines the importance of meninges as a potential niche for endogenous precursor cells during development and in adulthood.

Inflammatory molecules in Frontotemporal Dementia: cerebrospinal fluid signature of progranulin mutation carriers

Mutations in progranulin gene (GRN) are one of the major causes of autosomal dominant Frontotemporal Lobar Degeneration (FTLD). Progranulin displays anti-inflammatory properties and is likely a ligand of Tumor Necrosis Factor (TNF) receptor 2, expressed on microglia. A few cytokines and chemokines are altered in cerebrospinal fluid (CSF) from patients with sporadic FTLD, whereas no information is available in familial cases. We evaluated, through BioPlex, levels of 27 inflammatory molecules, including cytokines, chemokines, and related receptors, in CSF and matched serum, from FTLD patients carrying GRN mutations as compared with sporadic FTLD with no GRN mutations and controls. Mean±SD Monocyte Chemoattractant Protein-1 (MCP-1) levels were significantly increased in CSF from sporadic FTLD patients as compared with controls (334.27±151.5 versus 159.7±49pg/ml; P⩽0.05). In GRN mutation carriers versus controls, CSF levels of MCP-1 were unchanged, whereas Interferon-γ-inducible protein-10 (IP-10) levels were increased (809.17±240.0 versus 436.61±202.5pg/ml; P=0.012). In the same group, TNFα and Interleukin (IL)-15 levels were decreased (3.18±1.41 versus 35.68±30.5pg/ml; P=0.013 and 9.34±5.54 versus 19.15±10.03pg/ml; P=0.023, respectively). Conversely, Regulated upon Activation, Normal T-cell Expressed, and Secreted (RANTES) levels were decreased in patients, with or without mutations, as compared with controls (4.63±3.30 and 2.58±20 versus 87.57±70pg/ml, respectively; P<0.05). Moreover, IP-10, IL-15 and RANTES CSF levels were not influenced by age, whereas MCP-1 levels increased with age (ρ=0.48; P=0.007). In conclusion, inflammatory de-regulation was observed in both sporadic FTLD and GRN carriers compared to controls, with a specific inflammatory profile for the latter group.

Comparative study of immune regulatory properties of stem cells derived from different tissues

Allogeneic stem cell (SC)-based therapy is a promising tool for the treatment of a range of human degenerative and inflammatory diseases. Many reports highlighted the immune modulatory properties of some SC types, such as mesenchymal stromal cells (MSCs), but a comparative study with SCs of different origin, to assess whether immune regulation is a general SC property, is still lacking. To this aim, we applied highly standardized methods employed for MSC characterization to compare the immunological properties of bone marrow-MSCs, olfactory ectomesenchymal SCs, leptomeningeal SCs, and three different c-Kit-positive SC types, that is, amniotic fluid SCs, cardiac SCs, and lung SCs. We found that all the analyzed human SCs share a common pattern of immunological features, in terms of expression of activation markers ICAM-1, VCAM-1, HLA-ABC, and HLA-DR, modulatory activity toward purified T, B, and NK cells, lower immunogenicity of inflammatory-primed SCs as compared to resting SCs, and indoleamine-2,3-dioxygenase-activation as molecular inhibitory pathways, with some SC type-related peculiarities. Moreover, the SC types analyzed exert an anti-apoptotic effect toward not-activated immune effector cells (IECs). In addition, we found that the inhibitory behavior is not a constitutive property of SCs, but is acquired as a consequence of IEC activation, as previously described for MSCs. Thus, immune regulation is a general property of SCs and the characterization of this phenomenon may be useful for a proper therapeutic use of SCs.

Meninges: from protective membrane to stem cell niche

Meninges are a three tissue membrane primarily known as coverings of the brain. More in depth studies on meningeal function and ultrastructure have recently changed the view of meninges as a merely protective membrane. Accurate evaluation of the anatomical distribution in the CNS reveals that meninges largely penetrate inside the neural tissue. Meninges enter the CNS by projecting between structures, in the stroma of choroid plexus and form the perivascular space (Virchow-Robin) of every parenchymal vessel. Thus, meninges may modulate most of the physiological and pathological events of the CNS throughout the life. Meninges are present since the very early embryonic stages of cortical development and appear to be necessary for normal corticogenesis and brain structures formation. In adulthood meninges contribute to neural tissue homeostasis by secreting several trophic factors including FGF2 and SDF-1. Recently, for the first time, we have identified the presence of a stem cell population with neural differentiation potential in meninges. In addition, we and other groups have further described the presence in meninges of injury responsive neural precursors. In this review we will give a comprehensive view of meninges and their multiple roles in the context of a functional network with the neural tissue. We will highlight the current literature on the developmental feature of meninges and their role in cortical development. Moreover, we will elucidate the anatomical distribution of the meninges and their trophic properties in adult CNS. Finally, we will emphasize recent evidences suggesting the potential role of meninges as stem cell niche harbouring endogenous precursors that can be activated by injury and are able to contribute to CNS parenchymal reaction.

Nestin- and doublecortin-positive cells reside in adult spinal cord meninges and participate in injury-induced parenchymal reaction

Adult spinal cord has little regenerative potential, thus limiting patient recovery following injury. In this study, we describe a new population of cells resident in the adult rat spinal cord meninges that express the neural stem/precursor markers nestin and doublecortin. Furthermore, from dissociated meningeal tissue a neural stem cell population was cultured in vitro and subsequently shown to differentiate into functional neurons or mature oligodendrocytes. Proliferation rate and number of nestin- and doublecortin-positive cells increased in vivo in meninges following spinal cord injury. By using a lentivirus-labeling approach, we show that meningeal cells, including nestin- and doublecortin-positive cells, migrate in the spinal cord parenchyma and contribute to the glial scar formation. Our data emphasize the multiple roles of meninges in the reaction of the parenchyma to trauma and indicate for the first time that spinal cord meninges are potential niches harboring stem/precursor cells that can be activated by injury. Meninges may be considered as a new source of adult stem/precursor cells to be further tested for use in regenerative medicine applied to neurological disorders, including repair from spinal cord injury. Stem Cells 2011;29:2062–2076.

Neural stem cell niches in health and diseases

Presence of neural stem cells in adult mammalian brains, including human, has been clearly demonstrated by several studies. The functional significance of adult neurogenesis is slowly emerging as new data indicate the sensitivity of this event to several "every day" external stimuli such as physical activity, learning, enriched environment, aging, stress and drugs. In addition, neurogenesis appears to be instrumental for task performance involving complex cognitive functions. Despite the growing body of evidence on the functional significance of NSC and despite the bulk of data concerning the molecular and cellular properties of NSCs and their niches, several critical questions are still open. In this work we review the literature describing i) old and new sites where NSC niche have been found in the CNS; ii) the intrinsic factors regulating the NSC potential; iii) the extrinsic factors that form the niche microenvironment. Moreover, we analyse NSC niche activation in iv) physiological and v) pathological conditions. Given the not static nature of NSCs that continuously change phenotype in response to environmental clues, a unique "identity card" for NSC identification is still lacking. Moreover, the multiple location of NSC niches that increase in diseases, leaves open the question of whether and how these structures communicate throughout long distance. We propose a model where all the NSC niches in the CNS may be connected in a functional network using the threads of the meningeal net as tracks.

GABAergic neurons expressing p75 in rat substantia innominata and nucleus basalis

In vitro findings suggested a role for the p75 neurotrophin receptor in the maturation of GABAergic neurons residing in the basal forebrain (BF), a brain area known to have p75 expression only on cholinergic neurons. We document here the presence of GABAergic neurons which express p75 in the BF in vivo. Colocalization of p75 with the cholinergic marker choline-acetyltransferase (ChAT) and/or the GABAergic marker glutamic acid decarboxylase-67 (GAD67) was investigated in the BF at birth, at two weeks, and in adulthood. A subset of GAD67(+) neurons was p75(+) (p75(+)/GAD67(+)) but ChAT(-) in the substantia innominata and nucleus basalis magnocellularis at birth, whereas all p75(+)/GAD67(+) neurons were also ChAT(+) from two weeks onward. These phenotypic features suggest that a subpopulation of GABAergic neurons could be sensitive to neurotrophins during brain maturation. To unravel this issue, we then pursued a functional analysis by assessing p75 expression profile, and its modulation by nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF) in primary BF cell cultures. NGF increased p75 expression exclusively in cholinergic neurons, whereas BDNF induced p75 expression only in a subset of GABAergic neurons (p75(+)/GAD67(+)/ChAT(-)) through a p75- and tyrosine-kinase-dependent mechanism. The latter findings point to a selective role of BDNF in the induction of p75 expression in BF GABAergic neurons. Altogether these results confirm the role of neurotrophins in the developing and mature circuitry of GABAergic neurons in the BF regions.

Specific proteolytic cleavage of agrin regulates maturation of the neuromuscular junction

During the initial stage of neuromuscular junction (NMJ) formation, nerve-derived agrin cooperates with muscle-autonomous mechanisms in the organization and stabilization of a plaque-like postsynaptic specialization at the site of nerve–muscle contact. Subsequent NMJ maturation to the characteristic pretzel-like appearance requires extensive structural reorganization. We found that the progress of plaque-to-pretzel maturation is regulated by agrin. Excessive cleavage of agrin via transgenic overexpression of an agrin-cleaving protease, neurotrypsin, in motoneurons resulted in excessive reorganizational activity of the NMJs, leading to rapid dispersal of the synaptic specialization. By contrast, expression of cleavage-resistant agrin in motoneurons slowed down NMJ remodeling and delayed NMJ maturation. Neurotrypsin, which is the sole agrin-cleaving protease in the CNS, was excluded as the physiological agrin-cleaving protease at the NMJ, because NMJ maturation was normal in neurotrypsin-deficient mice. Together, our analyses characterize agrin cleavage at its proteolytic α- and β-sites by an as-yet-unspecified protease as a regulatory access for relieving the agrin-dependent constraint on endplate reorganization during NMJ maturation.

Propranolol transiently inhibits reinstatement of nicotine-seeking behaviour in rats

Noradrenergic transmission has been implicated in the affective component of relapse to tobacco smoking. Evidence in human and laboratory animals showed that smoking or nicotine administration may cause changes of the noradrenergic system resulting in hyperactivity in this system after cessation. It has been hypothesised that the anti-adrenergic beta-blocker propranolol may decrease affective activation and arousal observed during drug withdrawal or cue-induced relapse. The aim of the present work was to test the effects of propranolol pre-treatment in a rat model of nicotine cue-induced relapse to nicotine seeking. We also tested the effects of propranolol on food cue-induced reinstatement of food seeking in rats trained on food self-administration. Propranolol transiently inhibited nicotine cue-induced reinstatement. The inhibitory effect of propranolol reached a peak after 30 min from the beginning of the reinstatement session and then it declined until it was completely absent at the end of the 3-h session. This inhibitory effect of propranolol was not observed when the drug was tested versus reinstatement with food cues. The present study suggests a weak effect of propranolol to counteract nicotine cue-induced reinstatement of nicotine seeking. Therefore, these findings do not support a potential use of propranolol for prevention of smoking relapse.

Novel stem/progenitor cells with neuronal differentiation potential reside in the leptomeningeal niche

Stem cells capable of generating neural differentiated cells are recognized by the expression of nestin and reside in specific regions of the brain, namely, hippocampus, subventricular zone and olfactory bulb. For other brain structures, such as leptomeninges, which contribute to the correct cortex development and functions, there is no evidence so far that they may contain stem/precursor cells. In this work, we show for the first time that nestin-positive cells are present in rat leptomeninges during development up to adulthood. The newly identified nestin-positive cells can be extracted and expanded in vitro both as neurospheres, displaying high similarity with subventricular zone-derived neural stem cells, and as homogeneous cell population with stem cell features. In vitro expanded stem cell population can differentiate with high efficiency into excitable cells with neuronal phenotype and morphology. Once injected into the adult brain, these cells survive and differentiate into neurons, thus showing that their neuronal differentiation potential is operational also in vivo. In conclusion, our data provide evidence that a specific population of immature cells endowed of neuronal differentiation potential is resident in the leptomeninges throughout the life. As leptomeninges cover the entire central nervous system, these findings could have relevant implications for studies on cortical development and for regenerative medicine applied to neurological disorders.

Nicotine-induced phosphorylation of phosphorylated cyclic AMP response element-binding protein (pCREB) in hippocampal neurons is potentiated by agrin

The scope of this study was to test whether increased levels of the extracellular matrix molecule (ECM) agrin might enhance nicotine effects on those molecular mechanisms that initiate neuroadaptative processes in the hippocampus, a key brain area for learning and memory. We studied the effects of repetitive applications of neuronal agrin to primary hippocampal cell culture on nicotine-induced phosphorylated cyclic AMP response element-binding protein (pCREB) expression, a marker of neuroadaptation, by using immunofluorescence-based assessment of pCREB-positive neurons. We also tested agrin effects on nicotine-induced expression of a marker of metabolic activation, the immediate early gene c-fos. Agrin was shown to significantly enhance nicotine-induced pCREB, but not c-fos, expression. By using Western blotting analysis, cumulative agrin has been shown to increase nicotine-induced pCREB phosphorylation. These analyses, however, showed that inhibition of the CaMKII pathway blocked general pCREB phosphorylation, whereas inhibition of the MAPK pathway potentiated the synergistic effect of cumulative agrin and nicotine. These findings suggest that increasing the concentration of an ECM molecule, i.e. agrin, may enhance nicotine effects on pCREB and that both MAPK and CaMKII signalling may play a regulatory role.

Mechanisms of acetylcholine receptor loss from the neuromuscular junction

At the normal mammalian neuromuscular junction the half-life of the acetylcholine receptor (AChR) ranges from 6 to 13 days (estimates from seven different laboratories). Indirect evidence suggests that the internalized receptor is degraded by a lysosomal mechanism. We have now traced the fate of the AChR labelled in vivo with peroxidase-alpha-bungarotoxin. Segments of junctional folds bearing AChRs are internalized by endocytosis. The endocytosed vesicles are engulfed by tubules and larger vesicles which, by electron cytochemical criteria, represent secondary lysosomes. Pathological mechanisms increased AChR loss from the end-plate. These include destruction of junctional folds, formation of immature junctions with a few or no junctional folds, accelerated internalization of AChR, impaired membrane insertion of new AChR and, possibly decreased AChR synthesis. The common mechanism for destruction of the junctional folds is an altered subsynaptic ionic milieu, and especially focal calcium excess. This can be induced by antibody and complement, too frequent or prolonged openings of the acetylcholine (ACh)-induced ion channel, and other membrane defects. In acquired autoimmune myasthenia gravis there is (a) antibody-dependent complement-mediated lysis of the junctional folds, (b) accelerated internalization of AChR cross-linked by antibody and (c) decreased insertion of AChR into the postsynaptic membrane. The last mechanism is attributed to lack of membrane patches available for tight packing and secure anchoring of the receptor. In acute, but not in chronic, experimental autoimmune myasthenia gravis, and infrequently in human myasthenia gravis, macrophages destroy junctional folds opsonized by antibody and C3. In a recently recognized congenital syndrome attributed to a prolonged open time of the ACh-induced ion channel, and to a lesser extent in congenital end-plate acetylcholinesterase deficiency, AChR is lost with degradation of junctional folds. In other, less well-defined, congenital syndromes there is deficiency or abnormal function of AChR. This could arise from decreased synthesis or membrane insertion or accelerated degradation of AChR, or from a structurally abnormal AChR with reduced affinity for ACh or with a diminished conductance or open time of its ion channel.

Efficacy of cancer chemotherapy in relation to synchronization of cortisol rhythm, immune status and psychospiritual profile in metastatic non-small cell lung cancer

BACKGROUND

The prognosis of cancer and the efficacy of the various anticancer therapies depend not only on tumor characteristics, but also on the endocrine and immune status of patients. Moreover, studies have shown that the clinical course of the neoplastic disease is also influenced by the psychospiritual status of patients. It is thus probable that the influence of psychospirituality on tumor growth may be mediated by the immunoneuroendocrine system, as demonstrated by the recent advances in psychoneuroendocrinological research. However, at present there are only few data on the possible link between the psychospiritual status and immunoendocrine functions of cancer patients. This study was carried out to investigate the relationships existing among the psychospiritual profile, cortisol rhythm and lymphocyte number before and after chemotherapy, and the efficacy of chemotherapy itself in advanced cancer patients.

PATIENTS AND METHODS

The study included 30 consecutive metastatic non-small cell lung cancer patients under chemotherapeutic treatment with cisplatin plus gemcitabine. The psychobiological investigations consisted of lymphocyte count, cortisol circadian rhythm, psychological profile using Rorschach test, and spiritual score, as assessed by a specific clinical test for spirituality. The control group consisted of 100 healthy volunteers. The patients who achieved a tumor regression, showed a significantly higher pre-treatment lymphocyte count and significantly lower alteration of the cortisol rhythm with respect to those who had no benefit from chemotherapy. Moreover, the lymphocyte mean number increased during chemotherapy in responder patients, whereas it progressively diminished in those who had disease progression. Lymphocytopenia and alterations of the cortisol rhythm prior to chemotherapy were associated with a loss of the psychosexual identity according the Rorschach test. Moreover, the mean spiritual score was lower in patients than in controls, although the difference was not significant. Finally, a low spiritual score prior to therapy was associated with a higher frequency of lymphocytopenia and cortisol rhythm alteration, as well as with a lower efficacy of chemotherapy itself.

CONCLUSION

This preliminary study would suggest that the psychospiritual status of cancer patients may influence the efficacy of chemotherapy through the immunoneuroendocrine system.

Neural agrin controls maturation of the excitation-contraction coupling mechanism in human myotubes developing in vitro

The aim of this study was to elucidate the mechanisms responsible for the effects of innervation on the maturation of excitation-contraction coupling apparatus in human skeletal muscle. For this purpose, we compared the establishment of the excitation-contraction coupling mechanism in myotubes differentiated in four different experimental paradigms: 1) aneurally cultured, 2) cocultured with fetal rat spinal cord explants, 3) aneurally cultured in medium conditioned by cocultures, and 4) aneurally cultured in medium supplemented with purified recombinant chick neural agrin. Ca2+ imaging indicated that coculturing human muscle cells with rat spinal cord explants increased the fraction of cells showing a functional excitation-contraction coupling mechanism. The effect of spinal cord explants was mimicked by treatment with medium conditioned by cocultures or by addition of 1 nM of recombinant neural agrin to the medium. The treatment with neural agrin increased the number of human muscle cells in which functional ryanodine receptors (RyRs) and dihydropyridine-sensitive L-type Ca2+ channels were detectable. Our data are consistent with the hypothesis that agrin, released from neurons, controls the maturation of the excitation-contraction coupling mechanism and that this effect is due to modulation of both RyRs and L-type Ca2+ channels. Thus, a novel role for neural agrin in skeletal muscle maturation is proposed.

Immune and endocrine mechanisms of advanced cancer-related hypercortisolemia

BACKGROUND

Cancer progression depend on the immune and endocrine status of the patients. In particular, it has been observed that abnormally high levels of cortisol and/or an altered circadian secretion are associated with a poor prognosis in advanced cancer patients. The present study was performed to establish whether cancer-induced hypercortisolemia depends on an activation of the hypothalamic-pituitary axis or on a direct adrenal stimulation by inflammatory cytokines, such as IL-6, which have been proven to induce cortisol secretion.

PATIENTS AND METHODS

The study included 50 metastatic solid tumor patients, who were evaluated before the onset of chemotherapy. Venous blood samples were collected in the morning to measure IL-10, IL-6, ACTH and cortisol serum levels. Moreover, to analyze its circadian secretion, cortisol levels were also evaluated on venous blood samples collected at 4.00 p.m.

RESULTS

Abnormally high morning levels of cortisol were observed in 19/50 (38%) patients. Moreover, a lack of a normal circadian rhythm of cortisol was seen in 8/50 (16%) patients. None of the patients showed high levels of ACTH. Abnormally high concentrations of IL-6 and IL-10 were present in 21/50 (42%) and in 14/50 (28%) patients, respectively. Mean serum levels of both IL-6 and IL-10 were significantly higher in patients with hypercortisolemia than in those with normal cortisol values (p<0.005 and p<0.001, respectively). According to previous clinical studies, these results confirm that the advanced neoplastic disease may be associated with enhanced cortisol levels and alterations of its circadian secretion. The lack of enhanced ACTH secretion excludes the possibility that the abnormal cortisol production is due to the activation of the hypothalamic-pituitary axis. On the contrary, the evidence of significantly higher concentrations of IL-6 in hypercortisolemic patients would suggest that cancer-related enhanced cortisol production may depend on a direct adrenal stimulation by IL-6 itself The well-demonstrated stimulatory role of cortisol on IL-10 production would explain the enhanced IL-10 secretion in hypercortisolemic patients.

CONCLUSION

Cancer-related hypercortisolemia would seem to depend on alterations of the feedback mechanisms between endocrine and cytokine secretions, occurring in the neoplastic disease.

SK3 trafficking in hippocampal cells: the role of different molecular domains

The regulative steps that control trafficking of ion channels are fundamental determinants of their qualitative and quantitative expression on the cell membrane. In this work the trafficking of the small conductance calcium-activated potassium channel, SK3 was studied in neurons in order to identify relevant molecular domains involved in this process. Hippocampal cell cultures were transfected with fusion proteins of green fluorescent protein (GFP) and different SK3 subunit truncations. The differential distribution of the mutants was analyzed by confocal microscopy and compared to the localization of the control fusion protein with full length SK3. The transport of chimeric proteins was quantified from fluorescence images by developing a morphometric analytical method. We found that the full length SK3 was distributed in cell body, axon and dendrites, whereas the deleted forms GFPDelta578-736 (deletion of the entire C-terminal domain), GFPDeltaCaMBD (deletion of the calmodulin-binding site) and GFPDeltaN (deletion of the N-terminal domain) were not transported into cell processes but accumulated in the cell body. The GFPDelta640-736 (deletion of the distal C-terminal domain) showed a distribution similar to control. The quantification and statistical analysis confirmed the differences in distribution across the three groups. In conclusion, the current work provides evidence for a fundamental role of the N-terminal domain and the calmodulin binding domain in SK3 trafficking in neurons.

Different accumulation of cisplatin, oxaliplatin and JM216 in sensitive and cisplatin-resistant human cervical tumour cells

The significance of reduced drug accumulation in resistance to cisplatin was investigated by using cisplatin, oxaliplatin and JM216 (hydrophobicity rank: JM216>oxaliplatin>cisplatin) in human squamous cell carcinoma cell line A431 and its cisplatin-resistant counterpart A431/Pt. While cisplatin showed a resistance factor of 2.6, oxaliplatin and JM216 circumvented the resistance. Platinum accumulation after cisplatin exposure was lower (2.4-fold) in A431/Pt than in A431 cells, whereas a similar accumulation was found in the two cell lines when oxaliplatin or JM216 were used, thereby suggesting the capability of the latter drugs to bypass the accumulation defect. In the A431 cell line platinum accumulated to a similar extent after exposure to cisplatin, oxaliplatin or JM216, while in A431/Pt cells, Platinum accumulation depended on the hydrophobicity of the drug, and an increased hydrophobicity favours the uptake. No difference in efflux of cisplatin was found between the two cell lines. The values of platinum-DNA binding in A431 cells were similar for cisplatin and JM216 and higher than those of oxaliplatin. In A431/Pt cells: (i) Pt-DNA binding levels of JM216 remained as in sensitive ones; (ii) Pt-DNA levels of cisplatin and oxaliplatin were very similar and nearly two-fold lower than those of JM216. Such results, in this cell system characterized by a low level of cisplatin resistance, support a model whereby platinum uptake occurs by a mechanism of facilitated diffusion, perhaps involving a gated channel, which can be lost during the selection of the drug-resistant variant(s). The hydrophobicity of the drug can be the key to bypass resistance.

Assembly and trafficking of human small conductance Ca2+-activated K+ channel SK3 are governed by different molecular domains

Intracellular trafficking is an important event in the control of type and number of ion channels expressed on the cell surface. In this study, we have identified molecular domains involved in assembly and trafficking of the human small conductance Ca2+-activated K+ channel SK3. Deletion of the N-terminus, the C-terminus, or the calmodulin-binding domain (CaMBD) led to retention of SK3 channels in the endoplasmic reticulum. Presence of the CaMBD allowed trafficking to the Golgi complex, and sequences downstream were required for efficient transport to the plasma membrane, suggesting several steps in the control of SK3 forward trafficking. Co-immunoprecipitation studies demonstrated that SK3 subunits lacking the N-terminus, the CaMBD, or the distal C-terminus, but not the entire C-terminus, were able to oligomerize with wild-type SK3 subunits. Thus, these two C-terminal regions of SK3 seem to contribute to assembly and trafficking of channels whereas the N-terminus is necessary for trafficking but not sufficient for oligomerization.

Mechanisms controlling sensitivity to platinum complexes: role of p53 and DNA mismatch repair

Although cisplatin is effective in the treatment of different types of tumors, resistance to treatment is a major limitation. In an attempt of overcoming resistance mechanisms, a large effort has been made to generate compounds with a different geometry. At present, the most clinically relevant compounds include mononuclear (i.e. oxaliplatin) as well as multinuclear platinum complexes (i.e. BBR 3464). The mechanisms of cellular response to platinum complexes have not been completely elucidated. Among the main pathways affecting cell sensitivity of these drugs a role for p53 has been proposed at least for cisplatin and BBR 3464. Our results indicate that, also in the case of oxaliplatin, cytotoxicity is modulated by this pathway. Indeed, the effect of oxaliplatin could be reduced in tumor cells expressing mutant p53. The DNA mismatch repair system also appears to be critical in regulating cellular sensitivity to cisplatin because the loss of DNA mismatch repair results in low level of resistance to cisplatin, but not to oxaliplatin. Thus, platinum compounds are endowed with differential capability to activate pathways of p53-dependent or independent apoptosis, and differential recognition by specific cellular systems is likely to be the critical determinant of the cell fate (death/survival) after drug exposure. Further molecular studies are required to better define the precise contribution of such pathways to the cellular responses of the clinically relevant platinum complexes. A complete understanding of the molecular basis of sensitivity to platinum drugs is expected to provide useful insights for the optimization of tumor treatment.

Modulation of nicotinic acetylcholine receptor turnover by tyrosine phosphorylation in rat myotubes

The muscle nicotinic acetylcholine receptor (AChR) turns over at different rates depending on stage of synaptogenesis and innervation. Tyrosine phosphorylation modulates desensitization, interaction with cytoskeleton and lateral mobility in the membrane of AChR. To determine whether tyrosine phosphorylation also modulates the turnover of AChR, myotubes in vitro were exposed to the tyrosine phosphatase inhibitor pervanadate. Our data indicate that a transient increase of phosphotyrosine levels stabilized a fraction of AChRs. The effects were limited to the non-epsilon subunit-containing AChRs already present in the membrane. Tyrosine phosphorylation of the receptor occurred on the beta subunit, was transient and stable molecules were not selectively tyrosine phosphorylated. The data indicate that modulation of phosphotyrosine levels in muscle cells provides signals to control AChR metabolic stability.

Neural agrin controls acetylcholine receptor stability in skeletal muscle fibers

At mammalian neuromuscular junctions (NMJs), innervation induces and maintains the metabolic stability of acetylcholine receptors (AChRs). To explore whether neural agrin may cause similar receptor stabilization, we injected neural agrin cDNA of increasing transfection efficiencies into denervated adult rat soleus (SOL) muscles. As the efficiency increased, the amount of recombinant neural agrin expressed in the muscles also increased. This agrin aggregated AChRs on muscle fibers, whose half-life increased in a dose-dependent way from 1 to 10 days. Electrical muscle stimulation enhanced the stability of AChRs with short half-lives. Therefore, neural agrin can stabilize aggregated AChRs in a concentration- and activity-dependent way. However, there was no effect of stimulation on AChRs with a long half-life (10 days). Thus, at sufficiently high concentrations, neural agrin alone can stabilize AChRs to levels characteristic of innervated NMJs.