Optimization of 3D Synthetic Scaffolds for Neuronal Tissue Engineering Applications.

The increasing prevalence of neurodegenerative diseases has spurred researchers to develop advanced 3D models that accurately mimic neural tissues. Hydrogels stand out as ideal candidates as their properties closely resemble those of the extracellular matrix. A critical challenge in this regard is to comprehend the influence of the scaffold's mechanical properties on cell growth and differentiation, thus enabling targeted modifications. In light of this, a synthesis and comprehensive analysis of acrylamide-based hydrogels incorporating a peptide has been conducted. Adequate cell adhesion and development is achieved due to their bioactive nature and specific interactions with cellular receptors. The integration of a precisely controlled physicochemical hydrogel matrix and inclusion of the arginine-glycine-aspartic acid peptide sequence has endowed this system with an optimal structure, thus providing a unique ability to interact effectively with biomolecules. The analysis fully examined essential properties governing cell behavior, including pore size, mechanical characteristics, and swelling ability. Cell-viability experiments were performed to assess the hydrogel's biocompatibility, while the incorporation of grow factors aimed to promote the differentiation of neuroblastoma cells. The results underscore the hydrogel's ability to stimulate cell viability and differentiation in the presence of the peptide within the matrix.

Mimicking the extracellular matrix by incorporating functionalized graphene into hybrid hydrogels.

The efficient functionalization of graphene with sulfonic groups using a sustainable approach facilitates the interaction of biomolecules with its surface. The inclusion of these graphene sheets inside a photopolymerized acrylamide-based hydrogel provides a 3D scaffold with viscoelastic behaviour closer to that found in natural tissues. Cell-culture experiments and differentiation assays with SH-SY5Y cells showed that these hybrid hydrogels are non-cytotoxic, thus making them potentially useful as scaffold materials mimicking the extracellular environment.

CoQ10 reduces glioblastoma growth and infiltration through proteome remodeling and inhibition of angiogenesis and inflammation.

PURPOSE: Most monotherapies available against glioblastoma multiforme (GBM) target individual hallmarks of this aggressive brain tumor with minimal success. In this article, we propose a therapeutic strategy using coenzyme Q10 (CoQ10) as a pleiotropic factor that crosses the blood-brain barrier and accumulates in cell membranes acting as an antioxidant, and in mitochondrial membranes as a regulator of cell bioenergetics and gene expression. METHODS: Xenografts of U251 cells in nu/nu mice were used to assay tumor growth, hypoxia, angiogenesis, and inflammation. An orthotopic model was used to explore microglial infiltration, tumor growth, and invasion into the brain parenchyma. Cell proliferation, migration, invasion, proteome remodeling, and secretome were assayed in vitro. Conditioned media were used to assay angiogenesis, monocyte chemoattraction, and differentiation into macrophages in vitro. RESULTS: CoQ10 treatment decreased tumor volume in xenografts and orthotopic models, although its effect on tumor cell proliferation was not direct. Tumors from mice treated with CoQ10 were less hypoxic and vascularized, having less infiltration from inflammatory cells. Treatment-induced downregulation of HIF-1α and NF-kB led to a complete remodeling of the tumor cells proteome and secretome, impacting angiogenesis, monocyte infiltration, and their differentiation into macrophages. Besides, tumor cell migration and invasion were drastically restricted by mechanisms involving modulation of the actin cytoskeleton and downregulation of matrix metalloproteases (MMPs). CONCLUSIONS: CoQ10 has a pleiotropic effect on GBM growth, targeting several hallmarks simultaneously. Thus, its integration into current treatments of this fatal disease should be considered.

Early Effects of the Soluble Amyloid ß25-35 Peptide in Rat Cortical Neurons: Modulation of Signal Transduction Mediated by Adenosine and Group I Metabotropic Glutamate Receptors.

The amyloid ß peptide (Aß) is a central player in the neuropathology of Alzheimer's disease (AD). The alteration of Aß homeostasis may impact the fine-tuning of cell signaling from the very beginning of the disease, when amyloid plaque is not deposited yet. For this reason, primary culture of rat cortical neurons was exposed to Aß25-35, a non-oligomerizable form of Aß. Cell viability, metabotropic glutamate receptors (mGluR) and adenosine receptors (AR) expression and signalling were assessed. Aß25-35 increased mGluR density and affinity, mainly due to a higher gene expression and protein presence of Group I mGluR (mGluR1 and mGluR5) in the membrane of cortical neurons. Intriguingly, the main effector of group I mGluR, the phospholipase C ß1 isoform, was less responsive. Also, the inhibitory action of group II and group III mGluR on adenylate cyclase (AC) activity was unaltered or increased, respectively. Interestingly, pre-treatment of cortical neurons with an antagonist of group I mGluR reduced the Aß25-35-induced cell death. Besides, Aß25-35 increased the density of A1R and A2AR, along with an increase in their gene expression. However, while A1R-mediated AC inhibition was increased, the A2AR-mediated stimulation of AC remained unchanged. Therefore, one of the early events that takes place after Aß25-35 exposure is the up-regulation of adenosine A1R, A2AR, and group I mGluR, and the different impacts on their corresponding signaling pathways. These results emphasize the importance of deciphering the early events and the possible involvement of metabotropic glutamate and adenosine receptors in AD physiopathology.

Influence of biomedical education on health and eating habits of university students in Spain.

OBJECTIVE: The aim of this study was to explore the influence of an enrolled degree course on health and eating habits in a population of Spanish university students (17-26 y of age). METHODS: A cross-sectional observational study was carried out with 648 students. Volunteers were stratified into biomedical (medicine and nursing, 48%) and non-biomedical students (other fields of study, 52%). Data were collected using previously self-reported questionnaires focused on anthropometric and sociodemographic profile, lifestyle practices, body image perception, health consciousness, eating habits, physical activity, and food addiction. Mann-Whitney U tests and Pearson's χ2 tests were applied to identify associations between the two groups. RESULTS: Self-reported body mass index was higher for the non-biomedical group (22.1 ± 3.1 versus 23 ± 5 kg/m2; P < 0.05), which also reported less regularity in taking meals (91 versus 95%; P < 0.05), eating fewer colored vegetables and fruits (65 versus 77%; P < 0.001) and a higher alcohol intake (27 versus 20%; P < 0.001). In contrast, the proportion of students that showed more interest in the diet-health duality (92 versus 85%; P < 0.001) and a desire to adopt healthier habits (80 versus 78%; P < 0.05) was larger in the biomedical group. Dietary habits, obtained by means of a food frequency questionnaire, suggested that biomedical students make healthier food choices. Additionally, the group of biomedical students took more walks per week (5.8 ± 1.8 versus 5.5 ± 1.9; P < 0.05). CONCLUSIONS: Healthier lifestyle factors cluster into the biomedical group in various components of the study, except food addiction where no differences were observed. The data presented here suggest the necessity to develop health promotion strategies targeting university students.

The Role of Adenosine Receptors in Psychostimulant Addiction.

Adenosine receptors (AR) are a family of G-protein coupled receptors, comprised of four members, named A1, A2A, A2B, and A3 receptors, found widely distributed in almost all human body tissues and organs. To date, they are known to participate in a large variety of physiopathological responses, which include vasodilation, pain, and inflammation. In particular, in the central nervous system (CNS), adenosine acts as a neuromodulator, exerting different functions depending on the type of AR and consequent cellular signaling involved. In terms of molecular pathways and second messengers involved, A1 and A3 receptors inhibit adenylyl cyclase (AC), through Gi/o proteins, while A2A and A2B receptors stimulate it through Gs proteins. In the CNS, A1 receptors are widely distributed in the cortex, hippocampus, and cerebellum, A2A receptors are localized mainly in the striatum and olfactory bulb, while A2B and A3 receptors are found at low levels of expression. In addition, AR are able to form heteromers, both among themselves (e.g., A1/A2A), as well as with other subtypes (e.g., A2A/D2), opening a whole range of possibilities in the field of the pharmacology of AR. Nowadays, we know that adenosine, by acting on adenosine A1 and A2A receptors, is known to antagonistically modulate dopaminergic neurotransmission and therefore reward systems, being A1 receptors colocalized in heteromeric complexes with D1 receptors, and A2A receptors with D2 receptors. This review documents the present state of knowledge of the contribution of AR, particularly A1 and A2A, to psychostimulants-mediated effects, including locomotor activity, discrimination, seeking and reward, and discuss their therapeutic relevance to psychostimulant addiction. Studies presented in this review reinforce the potential of A1 agonists as an effective strategy to counteract psychostimulant-induced effects. Furthermore, different experimental data support the hypothesis that A2A/D2 heterodimers are partly responsible for the psychomotor and reinforcing effects of psychostimulant drugs, such as cocaine and amphetamine, and the stimulation of A2A receptor is proposed as a potential therapeutic target for the treatment of drug addiction. The overall analysis of presented data provide evidence that excitatory modulation of A1 and A2A receptors constitute promising tools to counteract psychostimulants addiction.

Noncoding RNA in the transcriptional landscape of human neural progenitor cell differentiation.

Increasing evidence suggests that noncoding RNAs play key roles in cellular processes, particularly in the brain. The present study used RNA sequencing to identify the transcriptional landscape of two human neural progenitor cell lines, SK-N-SH and ReNcell CX, as they differentiate into human cortical projection neurons. Protein coding genes were found to account for 54.8 and 57.0% of expressed genes, respectively, and alignment of RNA sequencing reads revealed that only 25.5-28.1% mapped to exonic regions of the genome. Differential expression analysis in the two cell lines identified altered gene expression in both protein coding and noncoding RNAs as they undergo neural differentiation with 222 differentially expressed genes observed in SK-N-SH cells and 19 differentially expressed genes in ReNcell CX. Interestingly, genes showing differential expression in SK-N-SH cells are enriched in genes implicated in autism spectrum disorder, but not in gene sets related to cancer or Alzheimer's disease. Weighted gene co-expression network analysis (WGCNA) was used to detect modules of co-expressed protein coding and noncoding RNAs in SK-N-SH cells and found four modules to be associated with neural differentiation. These modules contain varying levels of noncoding RNAs ranging from 10.7 to 49.7% with gene ontology suggesting roles in numerous cellular processes important for differentiation. These results indicate that noncoding RNAs are highly expressed in human neural progenitor cells and likely hold key regulatory roles in gene networks underlying neural differentiation and neurodevelopmental disorders.

Hippocampal changes produced by overexpression of the human CHRNA5/A3/B4 gene cluster may underlie cognitive deficits rescued by nicotine in transgenic mice.

Addiction involves long-lasting maladaptive changes including development of disruptive drug-stimuli associations. Nicotine-induced neuroplasticity underlies the development of tobacco addiction but also, in regions such as the hippocampus, the ability of this drug to enhance cognitive capabilities. Here, we propose that the genetic locus of susceptibility to nicotine addiction, the CHRNA5/A3/B4 gene cluster, encoding the α5, α3 and ß4 subunits of the nicotinic acetylcholine receptors (nAChRs), may influence nicotine-induced neuroadaptations. We have used transgenic mice overexpressing the human cluster (TgCHRNA5/A3/B4) to investigate hippocampal structure and function in genetically susceptible individuals. TgCHRNA5/A3/B4 mice presented a marked reduction in the dendrite complexity of CA1 hippocampal pyramidal neurons along with an increased dendritic spine density. In addition, TgCHRNA5/A3/B4 exhibited increased VGLUT1/VGAT ratio in the CA1 region, suggesting an excitatory/inhibitory imbalance. These hippocampal alterations were accompanied by a significant impairment in short-term novelty recognition memory. Interestingly, chronic infusion of nicotine (3.25 mg/kg/d for 7 d) was able to rescue the reduced dendritic complexity, the excitatory/inhibitory imbalance and the cognitive impairment in TgCHRNA5/A3/B4. Our results suggest that chronic nicotine treatment may represent a compensatory strategy in individuals with altered expression of the CHRNA5/A3/B4 region.

Differential Effect of Caffeine Consumption on Diverse Brain Areas of Pregnant Rats.

BACKGROUND: It has previously been shown that during gestation, the mother's brain has an increase in glial fibrillary acidic protein (GFAP)-immunoreactivity (-ir) and a decrease in the mRNA level of A1 adenosine receptor. Little is known about the A2A adenosine receptor in the maternal brain, and whether caffeine consumption throughout gestational period modifies GFAP and adenosine receptor density in specific brain areas. This study was undertaken to investigate the protein density of GFAP and adenosine receptors (A1 and A2A subtypes) in different regions of pregnant rat brain and the possible effect of caffeine on these proteins. METHODS: For this purpose, we examined the GFAP-, A1- and A2A-ir in the cingulate cortex (Cg2), dentate gyrus (DG), medial preoptic area (mPOA), secondary somatosensory cortex (S2), and striatum (Str) of pregnant Wistar rats (drug-free tap water or water with 1g/L diluted caffeine). RESULTS: We show a consistent and highly significant reduction of GFAP-ir in caffeine-treated pregnant rats in most of the areas analyzed. Our data demonstrate that caffeine consumption induces a significant increase of A2A-ir in Str. Concerning A1 receptor, the observed changes are dependent on the region analyzed; this receptor density is increased in Cg2, DG, and mPOA and decreased in the somatosensory cortex and Str. The results were confirmed by Western blotting. CONCLUSIONS: Our results suggest that chronic caffeine exposure could modify the physiolological situation of gestation by a reorganization of the neural circuits and the adenosine neuromodulator system.

Modulation of adenosine receptors by [60]fullerene hydrosoluble derivative in SK-N-MC cells.

The most known fullerenes are spherical carbon compounds composed of 60 carbon atoms. C(60) fullerenes have shown biochemical and biomedical properties in the last years such as as blockade of apoptosis and neuroprotection. The nucleoside adenosine has a neuroprotective role mainly due to inhibition of glutamate release, which is a neurotransmitter related to excitotoxicity and cell death. In the present work, we have determined the presence of adenosine receptors in SK-N-MC cells, a neuroepithelioma human cell line, and analyzed the effect of fullerenes in these receptors by using radioligand binding, immunoblotting, and quantitative real time PCR assays. Results demonstrated that SK-N-MC cells endogenously express adenosine receptors. Fullerene exposure of these cells did not affect cell viability measured by MTT reduction assay. However, adenosine A(1) and A(2A) receptors were both increased in SK-N-MC cells after treatment. These results suggest for the first time the modulation of adenosine receptors after C(60) fullerenes exposure.

Glutamate differently modulates excitatory and inhibitory adenosine receptors in neuronal and glial cells.

Adenosine is a neuromodulator which acts through adenosine receptors regulating functions such as inhibition of glutamate release. Adenosine A(1) and A(2A) receptor activations most often regulate opposing actions. Primary rat cortical neurons and rat C6 cells, an astrocytic derived cell line, were exposed to 100muM l-glutamate, and cell viability and transduction pathways mediated by both A(1) and A(2A) receptors were analyzed. Glutamate-induced excitotoxic damage was found only in cortical neurons, with C6 cells preserved. In C6 cells, adenosine A(1) and A(2A) receptors were increased and decreased, respectively. Consequently, A(1)-mediated adenylyl cyclase inhibition and A(2A)-mediated adenylyl cyclase stimulation were, respectively, increased and decreased after glutamate exposure. In cortical neurons, glutamate treatment increased both A(1) and A(2A) receptors. Moreover, adenylyl cyclase responsiveness to A(1) or A(2A) receptor agonists was heightened in these cells, in which pharmacological activation of AC induced cell death. Finally, activation of A(1) receptor or blockade of A(2A) receptor during glutamate treatment partially prevented the glutamate-induced cell death detected in cultured cortical neurons. Results show that adenosine receptors are regulated by glutamate, and that this regulation is dependent on the cell type, suggesting that adenosine receptors might be promising targets in the therapy against excitotoxic cell death.

Glutamate differently modulates metabotropic glutamate receptors in neuronal and glial cells.

Glutamate is an excitatory neurotransmitter implicated in learning and memory processes, but at high concentrations it acts as an excitotoxin causing degeneration and neuronal death. The aim of this work was to determine the excitotoxic effect of glutamate and the regulation of metabotropic glutamate receptors (mGluR) during excitotoxicity in neurons and C6 glioma cells. Results show that glutamate causes excitotoxic damage only in cortical neurons. Loss of cell viability in neurons was glutamate concentration- and time-dependent. Total mGluR levels were significantly reduced in these cells when exposed to glutamate. However, in C6 cells, which have been used as a model of glial cells, these receptors were regulated in a biphasic manner, decreased after 6 h, and increased after 24/48 h of treatment. Results show a cell dependent mGluR regulation by glutamate exposure which could mediate the vulnerability or not to glutamate mediated excitotoxicity.