Hormonal and psychological influences on performance anxiety in adolescent female volleyball players: a multi-approach study

Background

The neuroendocrine system has important implications for affiliation behavior among humans and can be used to assess the correlation between social relationships, stress, and health. This can be influenced by social closeness; this aspect is the closeness towards another individual or a group of individuals such as a sports team. Sports performance anxiety is considered an unpleasant emotional reaction composed of physiological, cognitive, affective, and behavioral components. This motivates us to learn about the process that can influence the outcome of competition. Hormones and genetics would seem to influence outcome and performance. In this regard, many studies have focused on the exercise response as a function of ovarian hormones and it has been observed that progesterone is a hormone that plays a key role in reducing anxiety, and thus stress, in humans and other animals. On the other hand, high cortisol concentrations are known to contribute to increased anxiety levels. However, the salivary alpha-amylase (sAA) enzyme has been suggested as marker of acute stress than cortisol. Genetics also seem to influence anxiety and stress management as in the case of brain-derived neurotrophic factor (BDNF) and striatal dopamine transporter (DAT). Therefore, the study aims to investigate social closeness, as a measure of sports team cohesion that can influence athletes' performance results, and its ability to influence the secretion of hormones, such as progesterone and cortisol, that affect the management of sports anxiety while also taking into account genetic background during a volleyball match.

Methods

Twenty-six female volleyball players who volunteered participated in this study (mean ± SD: age, 12.07 ± 0.7 years), and played in the final of the provincial volleyball championship in Palermo. All girls were during the ovarian cycle, in detail between the follicular and early ovulatory phases.

Results

The results showed a significant decrease in salivary cortisol only in the winning group (p < 0.039). In fact, whilst in the latter the pre-match level was 7.7 ng/ml and then decreased to 4.5 ng/ml after the match, in the losers group change was not statistically significant (7.8 ng/ml vs 6.6 ng/ml pre- and post-match). As to the sAA concentration, the winning team showed a statistically significant variation between pre- and post-match than the losers (166.01 ± 250 U/ml vs 291.59 ± 241 U/ml) (p = 0.01).

Conclusion

Analyzing the results of the SAS-2 psychological test it is highlighted that, on average, the loser group was more anxious than the winning group, and this contributed to the final result. In conclusion, there is strong evidence supporting the state of the art that many factors can affect performance anxiety and thus the performance itself.

Involvement of Astrocytes in the Formation, Maintenance, and Function of the Blood-Brain Barrier

The blood-brain barrier (BBB) is a fundamental structure that protects the composition of the brain by determining which ions, metabolites, and nutrients are allowed to enter the brain from the blood or to leave it towards the circulation. The BBB is structurally composed of a layer of brain capillary endothelial cells (BCECs) bound to each other through tight junctions (TJs). However, its development as well as maintenance and properties are controlled by the other brain cells that contact the BCECs: pericytes, glial cells, and even neurons themselves. Astrocytes seem, in particular, to have a very important role in determining and controlling most properties of the BBB. Here, we will focus on these latter cells, since the comprehension of their roles in brain physiology has been continuously expanding, even including the ability to participate in neurotransmission and in complex functions such as learning and memory. Accordingly, pathological conditions that alter astrocytic functions can alter the BBB's integrity, thus compromising many brain activities. In this review, we will also refer to different kinds of in vitro BBB models used to study the BBB's properties, evidencing its modifications under pathological conditions.

Involvement of the H3.3 Histone Variant in the Epigenetic Regulation of Gene Expression in the Nervous System, in Both Physiological and Pathological Conditions

All the cells of an organism contain the same genome. However, each cell expresses only a minor fraction of its potential and, in particular, the genes encoding the proteins necessary for basal metabolism and the proteins responsible for its specific phenotype. The ability to use only the right and necessary genes involved in specific functions depends on the structural organization of the nuclear chromatin, which in turn depends on the epigenetic history of each cell, which is stored in the form of a collection of DNA and protein modifications. Among these modifications, DNA methylation and many kinds of post-translational modifications of histones play a key role in organizing the complex indexing of usable genes. In addition, non-canonical histone proteins (also known as histone variants), the synthesis of which is not directly linked with DNA replication, are used to mark specific regions of the genome. Here, we will discuss the role of the H3.3 histone variant, with particular attention to its loading into chromatin in the mammalian nervous system, both in physiological and pathological conditions. Indeed, chromatin modifications that mark cell memory seem to be of special importance for the cells involved in the complex processes of learning and memory.

An In Vitro Model of Glioma Development

Gliomas are the prevalent forms of brain cancer and derive from glial cells. Among them, astrocytomas are the most frequent. Astrocytes are fundamental for most brain functions, as they contribute to neuronal metabolism and neurotransmission. When they acquire cancer properties, their functions are altered, and, in addition, they start invading the brain parenchyma. Thus, a better knowledge of transformed astrocyte molecular properties is essential. With this aim, we previously developed rat astrocyte clones with increasing cancer properties. In this study, we used proteomic analysis to compare the most transformed clone (A-FC6) with normal primary astrocytes. We found that 154 proteins are downregulated and 101 upregulated in the clone. Moreover, 46 proteins are only expressed in the clone and 82 only in the normal cells. Notably, only 11 upregulated/unique proteins are encoded in the duplicated q arm of isochromosome 8 (i(8q)), which cytogenetically characterizes the clone. Since both normal and transformed brain cells release extracellular vesicles (EVs), which might induce epigenetic modifications in the neighboring cells, we also compared EVs released from transformed and normal astrocytes. Interestingly, we found that the clone releases EVs containing proteins, such as matrix metalloproteinase 3 (MMP3), that can modify the extracellular matrix, thus allowing invasion.

RNA-Binding Proteins as Epigenetic Regulators of Brain Functions and Their Involvement in Neurodegeneration

A central aspect of nervous system development and function is the post-transcriptional regulation of mRNA fate, which implies time- and site-dependent translation, in response to cues originating from cell-to-cell crosstalk. Such events are fundamental for the establishment of brain cell asymmetry, as well as of long-lasting modifications of synapses (long-term potentiation: LTP), responsible for learning, memory, and higher cognitive functions. Post-transcriptional regulation is in turn dependent on RNA-binding proteins that, by recognizing and binding brief RNA sequences, base modifications, or secondary/tertiary structures, are able to control maturation, localization, stability, and translation of the transcripts. Notably, most RBPs contain intrinsically disordered regions (IDRs) that are thought to be involved in the formation of membrane-less structures, probably due to liquid-liquid phase separation (LLPS). Such structures are evidenced as a variety of granules that contain proteins and different classes of RNAs. The other side of the peculiar properties of IDRs is, however, that, under altered cellular conditions, they are also prone to form aggregates, as observed in neurodegeneration. Interestingly, RBPs, as part of both normal and aggregated complexes, are also able to enter extracellular vesicles (EVs), and in doing so, they can also reach cells other than those that produced them.

Lactate Threshold Training Program on Patients with Multiple Sclerosis: A Multidisciplinary Approach

Physical activity could play a key role in improving the quality of life, particularly in patients with nervous system diseases such as multiple sclerosis (MS). Through lactacid anaerobic training, this study aims to investigate the effects at a bio-psycho-physical level to counteract the chronic fatigue associated with the pathology, and to improve mental health at a psychological and neurotrophic level. Eight subjects (age: 34.88 ± 4.45 years) affected by multiple sclerosis were involved. A lactate threshold training program was administered biweekly for 12 weeks at the beginning of the study (T0), at the end of the study (T1) and at 9 months after the end of the study (T2), with physical, psychological and hematochemicals parameters, and dietary habits being tested. The results obtained confirmed that lactacid exercise can influence brain-derived neurotrophic factor (BDNF) levels as well as dehydroepiandrosterone sulfate (DHEAS) levels. In addition, levels of baseline lactate, which could be best used as an energy substrate, showed a decrease after the protocol training. Self-efficacy regarding worries and concerns management significantly increased from T0 to T1. The eating attitudes test (EAT-26) did not highlight any eating disease in the patients with a normal diet enrolled in our study. Physical exercise also greatly influenced the patients psychologically and emotionally, increasing their self-esteem. Lactate threshold training, together with dietary habits, appears to exert synergic positive effects on inflammation, neural plasticity and neuroprotection, producing preventive effects on MS symptoms and progression.

Enzymatic Spermine Metabolites Induce Apoptosis Associated with Increase of p53, caspase-3 and miR-34a in Both Neuroblastoma Cells, SJNKP and the N-Myc-Amplified Form IMR5

Neuroblastoma (NB) is a common malignant solid tumor in children and accounts for 15% of childhood cancer mortality. Amplification of the N-Myc oncogene is a well-established poor prognostic marker in NB patients and strongly correlates with higher tumor aggression and resistance to treatment. New therapies for patients with N-Myc-amplified NB need to be developed. After treating NB cells with BSAO/SPM, the detection of apoptosis was determined after annexin V-FITC labeling and DNA staining with propidium iodide. The mitochondrial membrane potential activity was checked, labeling cells with the probe JC-1 dye. We analyzed, by real-time RT-PCR, the transcript of genes involved in the apoptotic process, to determine possible down- or upregulation of mRNAs after the treatment on SJNKP and the N-Myc-amplified IMR5 cell lines with BSAO/SPM. The experiments were carried out considering the proapoptotic genes Tp53 and caspase-3. After treatment with BSAO/SPM, both cell lines displayed increased mRNA levels for all these proapoptotic genes. Western blotting analysis with PARP and caspase-3 antibody support that BSAO/SPM treatment induces high levels of apoptosis in cells. The major conclusion is that BSAO/SPM treatment leads to antiproliferative and cytotoxic activity of both NB cell lines, associated with activation of apoptosis.

Involvement of Thyroid Hormones in Brain Development and Cancer

The development and maturation of the mammalian brain are regulated by thyroid hormones (THs). Both hypothyroidism and hyperthyroidism cause serious anomalies in the organization and function of the nervous system. Most importantly, brain development is sensitive to TH supply well before the onset of the fetal thyroid function, and thus depends on the trans-placental transfer of maternal THs during pregnancy. Although the mechanism of action of THs mainly involves direct regulation of gene expression (genomic effects), mediated by nuclear receptors (THRs), it is now clear that THs can elicit cell responses also by binding to plasma membrane sites (non-genomic effects). Genomic and non-genomic effects of THs cooperate in modeling chromatin organization and function, thus controlling proliferation, maturation, and metabolism of the nervous system. However, the complex interplay of THs with their targets has also been suggested to impact cancer proliferation as well as metastatic processes. Herein, after discussing the general mechanisms of action of THs and their physiological effects on the nervous system, we will summarize a collection of data showing that thyroid hormone levels might influence cancer proliferation and invasion.

Correlation between polymorphism of TYMS gene and toxicity response to treatment with 5-fluoruracil and capecitabine

Tumorigenesis is a multiphasic process in which genetic alterations guide the progressive transformation in cancer cells1. In order to evaluate the possible correlation between some gene variants and the risk of the toxicity development onset, two of the polymorphisms of the thymidylate synthase (TYMS), rs34743033 (2R/3R) and rs16430 (DEL/INS) were investigated. We enrolled in our study 47 patients from the Hospital of Sicily. Our preliminary findings suggest that there could be a linkage between the genotypes discussed and the development of the toxicity following the chemotherapy treatment. These results need to be confirmed by further studies, however this short paper offers some initial insight into the relationships between genetic background and the better outcome for patients.

Correlation between polymorphism of TYMS gene and toxicity response to treatment with 5-fluoruracil and capecitabine

Tumorigenesis is a multiphasic process in which genetic alterations guide the progressive transformation in cancer cells1. In order to evaluate the possible correlation between some gene variants and the risk of the toxicity development onset, two of the polymorphisms of the thymidylate synthase (TYMS), rs34743033 (2R/3R) and rs16430 (DEL/INS) were investigated. We enrolled in our study 47 patients from the Hospital of Sicily. Our preliminary findings suggest that there could be a linkage between the genotypes discussed and the development of the toxicity following the chemotherapy treatment. These results need to be confirmed by further studies, however this short paper offers some initial insight into the relationships between genetic background and the better outcome for patients.

Genomic and Non-Genomic Mechanisms of Action of Thyroid Hormones and Their Catabolite 3,5-Diiodo-L-Thyronine in Mammals

Since the realization that the cellular homologs of a gene found in the retrovirus that contributes to erythroblastosis in birds (v-erbA), i.e. the proto-oncogene c-erbA encodes the nuclear receptors for thyroid hormones (THs), most of the interest for THs focalized on their ability to control gene transcription. It was found, indeed, that, by regulating gene expression in many tissues, these hormones could mediate critical events both in development and in adult organisms. Among their effects, much attention was given to their ability to increase energy expenditure, and they were early proposed as anti-obesity drugs. However, their clinical use has been strongly challenged by the concomitant onset of toxic effects, especially on the heart. Notably, it has been clearly demonstrated that, besides their direct action on transcription (genomic effects), THs also have non-genomic effects, mediated by cell membrane and/or mitochondrial binding sites, and sometimes triggered by their endogenous catabolites. Among these latter molecules, 3,5-diiodo-L-thyronine (3,5-T2) has been attracting increasing interest because some of its metabolic effects are similar to those induced by T3, but it seems to be safer. The main target of 3,5-T2 appears to be the mitochondria, and it has been hypothesized that, by acting mainly on mitochondrial function and oxidative stress, 3,5-T2 might prevent and revert tissue damages and hepatic steatosis induced by a hyper-lipid diet, while concomitantly reducing the circulating levels of low density lipoproteins (LDL) and triglycerides. Besides a summary concerning general metabolism of THs, as well as their genomic and non-genomic effects, herein we will discuss resistance to THs and the possible mechanisms of action of 3,5-T2, also in relation to its possible clinical use as a drug.

Physical Activity and Brain Health

Physical activity (PA) has been central in the life of our species for most of its history, and thus shaped our physiology during evolution. However, only recently the health consequences of a sedentary lifestyle, and of highly energetic diets, are becoming clear. It has been also acknowledged that lifestyle and diet can induce epigenetic modifications which modify chromatin structure and gene expression, thus causing even heritable metabolic outcomes. Many studies have shown that PA can reverse at least some of the unwanted effects of sedentary lifestyle, and can also contribute in delaying brain aging and degenerative pathologies such as Alzheimer’s Disease, diabetes, and multiple sclerosis. Most importantly, PA improves cognitive processes and memory, has analgesic and antidepressant effects, and even induces a sense of wellbeing, giving strength to the ancient principle of “mens sana in corpore sano” (i.e., a sound mind in a sound body). In this review we will discuss the potential mechanisms underlying the effects of PA on brain health, focusing on hormones, neurotrophins, and neurotransmitters, the release of which is modulated by PA, as well as on the intra- and extra-cellular pathways that regulate the expression of some of the genes involved.

A 3D‑scaffold of PLLA induces the morphological differentiation and migration of primary astrocytes and promotes the production of extracellular vesicles

The present study analyzed the ability of primary rat astrocytes to colonize a porous scaffold, mimicking the reticular structure of the brain parenchyma extracellular matrix, as well as their ability to grow, survive and differentiate on the scaffold. Scaffolds were prepared using poly‑L‑lactic acid (PLLA) via thermally‑induced phase separation. Firstly, the present study studied the effects of scaffold morphology on the growth of astrocytes, evaluating their capability to colonize. Specifically, two different morphologies were tested, which were obtained by changing the polymer concentration in the starting solution. The structures were characterized by scanning electron microscopy, and a pore size of 20 µm (defined as the average distance between the pore walls) was detected. For comparison, astrocytes were also cultured in the traditional 2D culture system that we have been using since 2003. Then the effects of different substrates, such as collagen I and IV, and fibronectin were analyzed. The results revealed that the PLLA scaffolds, coated with collagen IV, served as very good matrices for astrocytes, which were observed to adhere, grow and colonize the matrix, acquiring their typical morphology. In addition, under these conditions, they secreted extracellular vesicles (EVs) that were compatible in size with exosomes. Their ability to produce exosomes was also suggested by transmission electron microscopy pictures which revealed both EVs and intracellular structures that could be interpreted as multivesicular bodies. The fact that these cells were able to adapt to the PLLA scaffold, together with our previous results, which demonstrated that brain capillary endothelial cells can grow and differentiate on the same scaffold, could support the future use of 3D brain cell co‑culture systems.

Extracellular Vesicle-Associated RNA as a Carrier of Epigenetic Information

Post-transcriptional regulation of messenger RNA (mRNA) metabolism and subcellular localization is of the utmost importance both during development and in cell differentiation. Besides carrying genetic information, mRNAs contain cis-acting signals (zip codes), usually present in their 5'- and 3'-untranslated regions (UTRs). By binding to these signals, trans-acting factors, such as RNA-binding proteins (RBPs), and/or non-coding RNAs (ncRNAs), control mRNA localization, translation and stability. RBPs can also form complexes with non-coding RNAs of different sizes. The release of extracellular vesicles (EVs) is a conserved process that allows both normal and cancer cells to horizontally transfer molecules, and hence properties, to neighboring cells. By interacting with proteins that are specifically sorted to EVs, mRNAs as well as ncRNAs can be transferred from cell to cell. In this review, we discuss the mechanisms underlying the sorting to EVs of different classes of molecules, as well as the role of extracellular RNAs and the associated proteins in altering gene expression in the recipient cells. Importantly, if, on the one hand, RBPs play a critical role in transferring RNAs through EVs, RNA itself could, on the other hand, function as a carrier to transfer proteins (i.e., chromatin modifiers, and transcription factors) that, once transferred, can alter the cell's epigenome.

Extracellular vesicles shed by melanoma cells contain a modified form of H1.0 linker histone and H1.0 mRNA-binding proteins

Extracellular vesicles (EVs) are now recognized as a fundamental way for cell-to-cell horizontal transfer of properties, in both physiological and pathological conditions. Most of EV-mediated cross-talk among cells depend on the exchange of proteins, and nucleic acids, among which mRNAs, and non-coding RNAs such as different species of miRNAs. Cancer cells, in particular, use EVs to discard molecules which could be dangerous to them (for example differentiation-inducing proteins such as histone H1.0, or antitumor drugs), to transfer molecules which, after entering the surrounding cells, are able to transform their phenotype, and even to secrete factors, which allow escaping from immune surveillance. Herein we report that melanoma cells not only secrete EVs which contain a modified form of H1.0 histone, but also transport the corresponding mRNA. Given the already known role in tumorigenesis of some RNA binding proteins (RBPs), we also searched for proteins of this class in EVs. This study revealed the presence in A375 melanoma cells of at least three RBPs, with apparent MW of about 65, 45 and 38 kDa, which are able to bind H1.0 mRNA. Moreover, we purified one of these proteins, which by MALDI-TOF mass spectrometry was identified as the already known transcription factor MYEF2.

Lactate as a Metabolite and a Regulator in the Central Nervous System

More than two hundred years after its discovery, lactate still remains an intriguing molecule. Considered for a long time as a waste product of metabolism and the culprit behind muscular fatigue, it was then recognized as an important fuel for many cells. In particular, in the nervous system, it has been proposed that lactate, released by astrocytes in response to neuronal activation, is taken up by neurons, oxidized to pyruvate and used for synthesizing acetyl-CoA to be used for the tricarboxylic acid cycle. More recently, in addition to this metabolic role, the discovery of a specific receptor prompted a reconsideration of its role, and lactate is now seen as a sort of hormone, even involved in processes as complex as memory formation and neuroprotection. As a matter of fact, exercise offers many benefits for our organisms, and seems to delay brain aging and neurodegeneration. Now, exercise induces the production and release of lactate into the blood which can reach the liver, the heart, and also the brain. Can lactate be a beneficial molecule produced during exercise, and offer neuroprotection? In this review, we summarize what we have known on lactate, discussing the roles that have been attributed to this molecule over time.

Aquaporins and Brain Tumors

Brain primary tumors are among the most diverse and complex human cancers, and they are normally classified on the basis of the cell-type and/or the grade of malignancy (the most malignant being glioblastoma multiforme (GBM), grade IV). Glioma cells are able to migrate throughout the brain and to stimulate angiogenesis, by inducing brain capillary endothelial cell proliferation. This in turn causes loss of tight junctions and fragility of the blood–brain barrier, which becomes leaky. As a consequence, the most serious clinical complication of glioblastoma is the vasogenic brain edema. Both glioma cell migration and edema have been correlated with modification of the expression/localization of different isoforms of aquaporins (AQPs), a family of water channels, some of which are also involved in the transport of other small molecules, such as glycerol and urea. In this review, we discuss relationships among expression/localization of AQPs and brain tumors/edema, also focusing on the possible role of these molecules as both diagnostic biomarkers of cancer progression, and therapeutic targets. Finally, we will discuss the possibility that AQPs, together with other cancer promoting factors, can be exchanged among brain cells via extracellular vesicles (EVs).

Regulation of mRNA transport, localization and translation in the nervous system of mammals (Review)

Post-transcriptional control of mRNA trafficking and metabolism plays a critical role in the actualization and fine tuning of the genetic program of cells, both in development and in differentiated tissues. Cis-acting signals, responsible for post-transcriptional regulation, reside in the RNA message itself, usually in untranslated regions, 5′ or 3′ to the coding sequence, and are recognized by trans-acting factors: RNA-binding proteins (RBPs) and/or non-coding RNAs (ncRNAs). ncRNAs bind short mRNA sequences usually present in the 3′-untranslated (3′-UTR) region of their target messages. RBPs recognize specific nucleotide sequences and/or secondary/tertiary structures. Most RBPs assemble on mRNA at the moment of transcription and shepherd it to its destination, somehow determining its final fate. Regulation of mRNA localization and metabolism has a particularly important role in the nervous system where local translation of pre-localized mRNAs has been implicated in developing axon and dendrite pathfinding, and in synapse formation. Moreover, activity-dependent mRNA trafficking and local translation may underlie long-lasting changes in synaptic efficacy, responsible for learning and memory. This review focuses on the role of RBPs in neuronal development and plasticity, as well as possible connections between ncRNAs and RBPs.

Oligodendroglioma cells synthesize the differentiation-specific linker histone H1˚ and release it into the extracellular environment through shed vesicles

Chromatin remodelling can be involved in some of the epigenetic modifications found in tumor cells. One of the mechanisms at the basis of chromatin dynamics is likely to be synthesis and incorporation of replacement histone variants, such as the H1° linker histone. Regulation of the expression of this protein can thus be critical in tumorigenesis. In developing brain, H1° expression is mainly regulated at the post-transcriptional level and RNA-binding proteins (RBPs) are involved. In the past, attention mainly focused on the whole brain or isolated neurons and little information is available on H1° expression in other brain cells. Even less is known relating to tumor glial cells. In this study we report that, like in maturing brain and isolated neurons, H1° synthesis sharply increases in differentiating astrocytes growing in a serum-free medium, while the corresponding mRNA decreases. Unexpectedly, in tumor glial cells both H1° RNA and protein are highly expressed, in spite of the fact that H1° is considered a differentiation-specific histone variant. Persistence of H1° mRNA in oligodendroglioma cells is accompanied by high levels of H1° RNA-binding activities which seem to be present, at least in part, also in actively proliferating, but not in differentiating, astrocytes. Finally, we report that oligodendroglioma cells, but not astrocytes, release H1° protein into the culture medium by shedding extracellular vesicles. These findings suggest that deregulation of H1° histone expression can be linked to tumorigenesis.

Aquaporin-4 distribution in control and stressed astrocytes in culture and in the cerebrospinal fluid of patients with traumatic brain injuries

Distribution of aquaporin-4 (AQP4) was studied by western analysis and immunofluorescence in rat astrocytes exposed to either hypothermic (30 °C) or hyperosmolar (0.45 M sucrose) stress, and in the cerebrospinal fluid (CSF) of patients who suffered traumatic brain injury (TBI). CSF was obtained from 5 healthy subjects and from 20 patients suffering from severe TBI. CSF samples were taken at admission and on days 3 and 5-7. Here we report that, in response to both hypothermia and hyperosmolar stress, AQP4 was markedly reduced in cultured astrocytes. We also found that AQP4 significantly increased in patients with severe brain injury in respect to healthy subjects (P < 0.002). AQP4 in CSF remained unchanged in patients with elevated intracranial pressure (ICP), whereas there was a clear tendency to further increase in those patients whose ICP could be controlled within the normal range. We conclude that AQP4 levels in CSF are elevated after TBI and it might serve as a useful biochemical marker to assess brain water metabolism in clinical settings.

Dietary fatty acids in metabolic syndrome, diabetes and cardiovascular diseases

In the last few decades, the prevalence of overweight and essential obesity has been undergoing a fast and progressive worldwide increase. Obesity has been in turn linked to type II diabetes, with the total number of diabetic patients worryingly increasing, in the last fifteen years, suggesting a pandemic phenomenon. At the same time, an increase in the prevalence of cardiovascular diseases has been also recorded. Increasing evidence suggests that the diet is involved in such escalation. In particular, the progressive globalization of food industry allowed massive supply, at a relatively low price, of a great variety of pre-packed food and bakery products, with very high energy content. Most of this food contains high amounts of saturated fatty acids (SFA) and of hydrogenated or trans fatty acids (TFA), that probably represent the prominent risk factors in the diet. Herein we will report diffusion and possible impact on health of such molecules, with reference to coronary heart disease, insulin resistance, metabolic syndrome and diabetes. We will also discuss the cellular and molecular mechanisms of action of fatty acids and fatty acid-derivatives which have been involved either in promoting or in preventing human pathologies. Free fatty acids (FFA) are not indeed only essential fuels for the organism. They also act as ligands for both membrane and nuclear receptors involved in different signaling pathways. Notably, some of these pathways can induce cell stress and apoptosis. Most important, FFA can affect glucose-induced insulin secretion and activate β-cell death. These events can be at least in part counteracted by polyunsaturated fatty acids.

RNA-binding activity of the rat calmodulin-binding PEP-19 protein and of the long PEP-19 isoform

Synthesis of H1˚ histone protein, in the developing rat brain, seems to be regulated mainly at the post-transcriptional level. Since regulation of RNA metabolism depends on a series of RNA-binding proteins, we have been searching for RNA-binding proteins involved in the post-transcriptional regulation of the H1˚ gene. We recently reported isolation, from a cDNA expression library, of an insert encoding a novel protein, the C-terminal half of which is identical to that of PEP-19, a brain-specific protein involved in calcium metabolism. The novel protein was called long PEP-19 isoform (LPI). Herein we show that LPI, as well as PEP-19, can bind H1˚ RNA. Moreover, in order to improve production of functional LPI/PEP-19, we modified the protocol normally adopted for preparing histidine tagged-proteins from bacteria, by adding an additional purification step. We also found that both LPI and PEP can compete for H1˚ RNA binding with PIPPin (CSD-C2), another RNA-binding protein previously discovered in our laboratory. Since PEP19/LPI contain a calmodulin binding domain, we finally investigated whether their ability to bind RNA is affected by calmodulin. Our results show that calmodulin interferes with binding of H1˚ RNA to both PEP-19 and LPI, while it is not able to bind RNA on its own. This finding suggests that calcium/calmodulin may have a role in controlling H1˚ mRNA metabolism in the developing brain.

Oligodendroglioma cells shed microvesicles which contain TRAIL as well as molecular chaperones and induce cell death in astrocytes

Microvesicles (MVs) shed from G26/24 oligodendroglioma cells were previously reported to cause a reproducible, dose-dependent, inhibitory effect on neurite outgrowth, and eventually neuronal apoptosis, when added to primary cultures of rat cortical neurons. These effects were reduced but not abolished by functional monoclonal antibodies against Fas-L. In order to investigate whether MVs contain other factors able to induce cell death, we tested them for TRAIL and found clear evidence of its presence in the vesicles. This finding suggests the possibility that Fas-L and TRAIL cooperate in inducing brain cell death. Aimed at understanding the route through which the vesicles deliver their messages to the target cells, we labeled oligodendroglioma cells with radioactive methionine and then added the labeled vesicles shed from tumor cells to unlabeled astrocytes in culture. Here we report that labeled proteins were delivered to the test cells. In order to investigate whether astrocytes, like neurons, are sensitive to oligodendroglioma-derived vesicles, MVs were prepared from media conditioned by G26/24 oligodendroglioma cells and added to primary cultures of rat cortical astrocytes. These cells were clearly more resistant than neurons to microvesicle-induced damage: a high dose (40 µg) of shed MVs induced cell death in only about 40% of astrocytes. Finally, we demonstrated that Hsp70 is specifically enriched in MVs which also contain, even if at lower level, the Hsc70 constitutive chaperone.

Biological effects of inorganic arsenic on primary cultures of rat astrocytes

It is well established that inorganic arsenic induces neurotoxic effects and neurological defects in humans and laboratory animals. The cellular and molecular mechanisms of its actions, however, remain elusive. Herein we report the effects of arsenite (NaAsO2) on primary cultures of rat astrocytes. Cells underwent induction of heat shock protein 70 only at the highest doses of inorganic arsenic (30 and 60 microM), suggesting a high threshold to respond to stress. We also investigated arsenic genotoxicity with the comet assay. Interestingly, although cells treated with 10 microM arsenite for 24 h maintained >70% viability, with respect to untreated cells, high DNA damage was already observed. Since arsenic is not known to be a direct-acting genotoxic agent, we investigated the possibility that its effects are due, in astrocytes as well, to ROS formation, as already described for other cell types. However, FACS analysis after CM-H2DCFDA staining did not evidence any significant increase of ROS production while, on the contrary, at the highest arsenite concentrations used, ROS production decreased. Concordantly, we found that, if most cells in the culture are still alive (i.e. up to 10 microM arsenite), they show a treatment-dependent increase in the concentration of SOD1. On the other hand, SOD2 concentration did not change. Finally, we found that astrocytes also synthesize PIPPin, an RNA-binding protein, the concentration of which was recently reported to change in response to stress induced by cadmium. Here we also report that, in cells exposed to high doses of arsenite, an anti-PIPPin antibody-positive faster migrating protein appears.

Neuronal and BBB damage induced by sera from patients with secondary progressive multiple sclerosis

An important component of the pathogenic process of multiple sclerosis (MS) is the blood-brain barrier (BBB) damage. We recently set an in vitro model of BBB, based on a three-cell-type co-culture system, in which rat neurons and astrocytes synergistically induce brain capillary endothelial cells to form a monolayer with permeability properties resembling those of the physiological BBB. Herein we report that the serum from patients with secondary progressive multiple sclerosis (SPMS) has a damaging effect on isolated neurons. This finding suggests that neuronal damaging in MS could be a primary event and not only secondary to myelin damage, as generally assumed. SPMS serum affects the permeability of the BBB model, as indicated by the decrease of the transendothelial electrical resistance (TEER). Moreover, as shown by both immunofluorescence and Western blot analyses, BBB breaking is accompanied by a decrease of the synthesis as well as the peripheral localization of occludin, a structural protein of the tight junctions that are responsible for BBB properties.

The effect of cadmium on brain cells in culture

Cadmium is a long-living heavy metal, abundantly present in the environment, which accumulates in the body. In this study, we investigated the effects of cadmium on the expression of molecular chaperones, and of certain cell-specific proteins, in a variety of brain cell types in culture, namely primary cultures of rat cortical neurons and astrocytes, a brain capillary endothelial cell line (RB4E.B cells), and pheochromocytoma cells (PC12), induced or not to differentiate by NGF treatment. The metal induces a dose-dependent increase of Hsp70 in all cell types. Responses to the metal are cell-specific in the case of Hsc70 and Hsp90: i) in astrocytes, as well as in PC12 cells, cadmium has no significant effect; ii) in endothelial cells, an increase of both proteins is clearly observable from 20 microM cadmium; iii) both Hsp90 and Hsc70 decrease in neurons treated with high doses of cadmium. Damage to the cytoskeleton in treated cells was also evident. Finally, we report that the metal at high doses induces a decrease of PIPPin (also known as CSD-C2), a putative RNA-binding protein highly expressed in neurons and probably involved in the regulation of histone replacement variant expression.

Neurons produce FGF2 and VEGF and secrete them at least in part by shedding extracellular vesicles

We previously found that neurons are able to affect the ability of brain capillary endothelial cells to form in vitro a monolayer with properties resembling the blood-brain barrier. We then looked, by immunofluorescence and western analysis, for factors, produced by neurons, with the potential to influence growth and differentiation of endothelial cells. In the present paper, we report that neurons produce both vascular endothelial growth factor and fibroblast growth factor 2, two well-known angiogenic factors. More interestingly, we gained evidence that both factors are released by neurons, at least in part, by shedding of extracellular vesicles, that contain beta1 integrin, a membrane protein already known to be part of extracellular vesicles released by tumour cells. Shedding of extracellular vesicles by neurons was also confirmed by scanner electron microscopy.

Thyroid hormones and the central nervous system of mammals (Review)

The thyroid hormones (THs) L-thyroxine (T4) and L-triiodothyronine (T3) have a profound influence on the development and maturation of the mammalian brain, both before and after birth. Any impairment in the supply of THs to the developing nervous system leads to severe and irreversible changes in both the overall architecture and functions of the brain and causes, in humans, neurological and motor deficits known as cretinism. Pronounced neurological symptoms are also commonly observed in adult patients suffering from both hyperthyroidism and hypothyroidism, and it has recently emerged that certain symptoms might result from the reduced brain uptake, rather than the insufficient production, of THs. Most of the effects of THs are mediated by two classes of nuclear receptors (α and β isoforms), which belong to the c-erbA superfamily of transcriptional regulators and are expressed in a tissue-specific and developmentally regulated manner. Interestingly, the nuclear TH receptors (nTRs) act as both ligand-independent gene repressors and ligand-dependent gene activators. On the other hand, negatively-regulated genes, which can be stimulated in the absence of THs and repressed by THs, have also been observed. Due to this complex pattern of regulation, the effects of receptor dysfunction do not exactly overlap the effects of hormone deficiency or excess. Moreover, non-genomic mechanisms of TH action have been described in many tissues, including the brain, some of which seem to be mediated by integrins and to be calcium-dependent. Intracellular receptors, distinct from nTRs, are present in the mitochondria, where a matrix-associated, T3-dependent transcriptional regulator of approximately 43 kDa has been described. Finally, complex patterns of pituitary and/or peripheral resistance to thyroid hormones (RTH), characterized by elevated plasma levels of THs and non-suppressible thyroid-stimulating hormone (TSH), have been identified. This review summarizes the major advances in knowledge of the molecular mechanisms of TH action and their implication for the effects of THs on the developing, as well as the adult mammalian, nervous system.

Astrocytes shed extracellular vesicles that contain fibroblast growth factor-2 and vascular endothelial growth factor

We previously set a three-cell-type coculture system in which neurons and astrocytes synergistically induce brain capillary endothelial cells to form a monolayer with permeability properties resembling those of the physiological blood-brain barrier. Moreover, we recently found that neurons produce fibroblast growth factor-2 and vascular endothelial growth factor and secrete them at least in part by shedding extracellular vesicles. In this study, on the basis of immunofluorescence, scanner electron microscopy and Western blot analyses, we concluded that also astrocytes in culture shed extracellular vesicles that contain the same angiogenic factors, as well as beta1-integrin, a membrane protein that is considered a marker of shedding. Vesicles released by astrocytes are smaller than the ones produced by neurons and have an average size of 150-500 nm.

Cloning of a rat-specific long PCP4/PEP19 isoform

We report the identification of a cDNA that encodes a putative protein of 94 amino acids and expected molecular weight of 10.7 kDa, the C-terminal half of which is identical to that of PEP19, a small, brain-specific protein involved in Ca++/calmodulin signaling. The novel rat-specific protein, tentatively named long PEP19 isoform (LPI), is the product of alternative splicing of the rat PCP4 gene encoding PEP19. We found that antibodies raised against the first 13 N-terminal amino acids of LPI, not present in PEP19, recognize a protein enriched in the developing rat brain.

Thyroid hormones induce sumoylation of the cold shock domain-containing protein PIPPin in developing rat brain and in cultured neurons

We previously identified a cold shock domain (CSD)-containing protein (PIPPin), expressed at high level in brain cells. PIPPin has the potential to undergo different posttranslational modifications and might be a good candidate to regulate the synthesis of specific proteins in response to extracellular stimuli. Here we report the effects of T(3) on PIPPin expression in developing rat brain. We found that a significant difference among euthyroid and hypothyroid newborn rats concerns sumoylation of nuclear PIPPin, which is abolished by hypothyroidism. Moreover, T(3) dependence of PIPPin sumoylation has been confirmed in cortical neurons purified from brain cortices and cultured in a chemically defined medium (Maat medium), with or without T(3). We also report that about one half of unmodified as well as all the sumoylated form of PIPPin could be extracted from nuclei with HCl, together with histones. Moreover, this HCl-soluble fraction remains in the nucleus even after treatment with 0.6 M KCl, thus suggesting strong interaction of PIPPin with nuclear structures and perhaps chromatin.

Membrane vesicles shed by oligodendroglioma cells induce neuronal apoptosis

In order to investigate the mechanism by which oligodendrogliomas cause neuronal damage, media conditioned by G26/24 oligodendroglioma cells, were fractionated into shed vesicles and vesicle-free supernatants, and added to primary cultures of rat fetal cortical neurons. After one night treatment with vesicles, a reproducible, dose-dependent, inhibitory effect on neurite outgrowth was already induced and, after 48-72 h of incubation, neuronal apoptosis was evident. Vesicle-free supernatants and vesicles shed by NIH-3T3 cells had no inhibitory effects on neurons. Western blot analyses showed that treated neurons expressed a decreased amount of neurofilament (NF), growth-associated protein (GAP-43) and microtubule-associated protein (MAP-2). Moreover procaspase-3 and -8 were activated while Bcl-2 expression was reduced. Vesicles were found positive for the proapoptotic molecule, Fas-ligand (Fas-L), and for the B isoform of Nogo protein, a myelin component with inhibitory effects on neurons. Nogo B involvement in the vesicle effects was analyzed both by testing the neutralizing capability of anti-Nogo antibodies and by removing the Nogo receptor from neurons by phospholipase C digestion. These treatments did not revert the vesicle effects. To test the role of Fas-L, vesicles were treated with functional anti-Fas-L monoclonals. Vesicle inhibitory and proapoptotic effects were reduced. Vesicles shed by ovarian carcinoma cells (OvCa), which are known to vehicle biologically active Fas-L, had similar effects on neurons to those of oligodendroglioma vesicles, and their inhibitory effects were also reduced by anti Fas-L antibodies. We therefore conclude that vesicles shed by G26/24 cells induce neuronal apoptosis at least partially by a Fas-L mediated mechanism.

Permeability properties of a three-cell type in vitro model of blood-brain barrier

We previously found that RBE4.B brain capillary endothelial cells (BCECs) form a layer with blood-brain barrier (BBB) properties if co-cultured with neurons for at least one week. As astrocytes are known to modulate BBB functions, we further set a culture system that included RBE4.B BCECs, neurons and astrocytes. In order to test formation of BBB, we measured the amount of 3H-sucrose able to cross the BCEC layer in this three-cell type model of BBB. Herein we report that both neurons and astrocytes induce a decrease in the permeability of the BCEC layer to sucrose. These effects are synergic as if BCECs are cultured with both neurons and astrocytes for 5 days, permeability to sucrose decreases even more. By Western analysis, we also found that, in addition to the canonical 60 kDa occludin, anti-occludin antibodies recognize a smaller protein of 48 kDa which accumulates during rat brain development. Interestingly this latter protein is present at higher amounts in endothelial cells cultured in the presence of both astrocytes and neurons, that is in those conditions in which sucrose permeation studies indicate formation of BBB.

Synergistic effects of neurons and astrocytes on the differentiation of brain capillary endothelial cells in culture

Brain capillary endothelial cells form a functional barrier between blood and brain, based on the existence of tight junctions that limit paracellular permeability. Occludin is one of the major transmembrane proteins of tight junctions and its peripheral localization gives indication of tight junction formation. We previously reported that RBE4.B cells (brain capillary endothelial cells), cultured on collagen IV, synthesize occludin and correctly localize it at the cell periphery only when cocultured with neurons. In the present study, we describe a three-cell type-culture system that allowed us to analyze the combined effects of neurons and astrocytes on differentiation of brain capillary endothelial cells in culture. In particular, we found that, in the presence of astrocytes, the neuron-induced synthesis and localization of occludin is precocious as compared to cells cocultured with neurons only.

Purification by affinity chromatography of H1o RNA-binding proteins from rat brain

Post-transcriptional regulation of mRNA metabolism is involved in processes as different as cell fate specification in development and cell response to a large variety of environmental cues. Regulation of all steps of RNA metabolism depends on RNA-binding proteins (RBPs). By using a T1 RNase-protection assay, we previously identified three H1 degrees RNA-binding factors (p40, p70 and p110), highly expressed in the rat brain. Here we report enrichment of these factors from brain extracts, obtained by affinity chromato-graphy of biotinylated H1 degrees RNA-protein complexes on streptavidin-conjugated paramagnetic particles. The purified proteins maintain RNA-binding ability and preference for histone messages.

RNA-binding ability of PIPPin requires the entire protein

Post-transcriptional fate of eukaryotic mRNAs depends on association with different classes of RNA-binding proteins (RBPs). Among these proteins, the cold-shock domain (CSD)-containing proteins, also called Y-box proteins, play a key role in controlling the recruitment of mRNA to the translational machinery, in response to environmental cues, both in development and in differentiated cells. We recently cloned a rat cDNA encoding a new CSD-protein that we called PIPPin. This protein also contains two putative double-stranded RNA-binding motifs (PIP(1) and PIP(2)) flanking the central CSD, and is able to bind mRNAs encoding H1 degrees and H3.3 histone variants. In order to clarify the role of each domain in the RNA-binding activity of PIPPin, we constructed a number of different recombinant vectors, encoding different regions of the protein. Here we report that only recombinant proteins that contain all the putative PIPPin domains show RNA-binding ability.

Isolation and characterization of a Paracentrotus lividus cDNA encoding a stress-inducible chaperonin

Chaperonins are ubiquitous proteins that facilitate protein folding in an adenosine triphosphate-dependent manner. Here we report the isolation of a sea urchin cDNA (Plhsp60) coding for mitochondrial chaperonin (Cpn60), whose basal expression is further enhanced by heat shock. The described cDNA corresponds to a full-length mRNA encoding a protein of 582 amino acids, the first 32 of which constitute a putative mitochondrial targeting leader sequence. Comparative analysis has demonstrated that this protein is highly conserved in evolution.