Microplastics and Nanoplastics in Atheromas and Cardiovascular Events.

BACKGROUND: Microplastics and nanoplastics (MNPs) are emerging as a potential risk factor for cardiovascular disease in preclinical studies. Direct evidence that this risk extends to humans is lacking. METHODS: We conducted a prospective, multicenter, observational study involving patients who were undergoing carotid endarterectomy for asymptomatic carotid artery disease. The excised carotid plaque specimens were analyzed for the presence of MNPs with the use of pyrolysis-gas chromatography-mass spectrometry, stable isotope analysis, and electron microscopy. Inflammatory biomarkers were assessed with enzyme-linked immunosorbent assay and immunohistochemical assay. The primary end point was a composite of myocardial infarction, stroke, or death from any cause among patients who had evidence of MNPs in plaque as compared with patients with plaque that showed no evidence of MNPs. RESULTS: A total of 304 patients were enrolled in the study, and 257 completed a mean (±SD) follow-up of 33.7±6.9 months. Polyethylene was detected in carotid artery plaque of 150 patients (58.4%), with a mean level of 21.7±24.5 µg per milligram of plaque; 31 patients (12.1%) also had measurable amounts of polyvinyl chloride, with a mean level of 5.2±2.4 µg per milligram of plaque. Electron microscopy revealed visible, jagged-edged foreign particles among plaque macrophages and scattered in the external debris. Radiographic examination showed that some of these particles included chlorine. Patients in whom MNPs were detected within the atheroma were at higher risk for a primary end-point event than those in whom these substances were not detected (hazard ratio, 4.53; 95% confidence interval, 2.00 to 10.27; P<0.001). CONCLUSIONS: In this study, patients with carotid artery plaque in which MNPs were detected had a higher risk of a composite of myocardial infarction, stroke, or death from any cause at 34 months of follow-up than those in whom MNPs were not detected. (Funded by Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale and others; ClinicalTrials.gov number, NCT05900947.).

Effects of extremely low-frequency magnetic fields on human MDA-MB-231 breast cancer cells: proteomic characterization.

Extremely low-frequency electromagnetic fields (ELF-MF) can modify the cell viability and regulatory processes of some cell types, including breast cancer cells. Breast cancer is a multifactorial disease where a role for ELF-MF cannot be excluded. ELF-MF may influence the biological properties of breast cells through molecular mechanisms and signaling pathways that are still unclear. This study analyzed the changes in the cell viability, cellular morphology, oxidative stress response and alteration of proteomic profile in breast cancer cells (MDA-MB-231) exposed to ELF-MF (50 Hz, 1 mT for 4 h). Non-tumorigenic human breast cells (MCF-10A) were used as control cells. Exposed MDA-MB-231 breast cancer cells increased their viability and live cell number and showed a higher density and length of filopodia compared with the unexposed cells. In addition, ELF-MF induced an increase of the mitochondrial ROS levels and an alteration of mitochondrial morphology. Proteomic data analysis showed that ELF-MF altered the expression of 328 proteins in MDA-MB-231 cells and of 242 proteins in MCF-10A cells. Gene Ontology term enrichment analysis demonstrated that in both cell lines ELF-MF exposure up-regulated the genes enriched in "focal adhesion" and "mitochondrion". The ELF-MF exposure decreased the adhesive properties of MDA-MB-231 cells and increased the migration and invasion cell abilities. At the same time, proteomic analysis, confirmed by Real Time PCR, revealed that transcription factors associated with cellular reprogramming were upregulated in MDA-MB-231 cells and downregulated in MCF-10A cells after ELF-MF exposure. MDA-MB-231 breast cancer cells exposed to 1 mT 50 Hz ELF-MF showed modifications in proteomic profile together with changes in cell viability, cellular morphology, oxidative stress response, adhesion, migration and invasion cell abilities. The main signaling pathways involved were relative to focal adhesion, mitochondrion and cellular reprogramming.

Keratinocytes Exposed to Blue or Red Light: Proteomic Characterization Showed Cytoplasmic Thioredoxin Reductase 1 and Aldo-Keto Reductase Family 1 Member C3 Triggered Expression.

Several cell-signaling mechanisms are activated by visible light radiation in human keratinocytes, but the key regulatory proteins involved in this specific cellular response have not yet been identified. Human keratinocytes (HaCaT cells) were exposed to blue or red light at low or high irradiance for 3 days in cycles of 12 h of light and 12 h of dark. The cell viability, apoptotic rate and cell cycle progression were analyzed in all experimental conditions. The proteomic profile, oxidative stress and mitochondrial morphology were additionally evaluated in the HaCaT cells following exposure to high-irradiance blue or red light. Low-irradiance blue or red light exposure did not show an alteration in the cell viability, cell death or cell cycle progression. High-irradiance blue or red light reduced the cell viability, induced cell death and cell cycle G2/M arrest, increased the reactive oxygen species (ROS) and altered the mitochondrial density and morphology. The proteomic profile revealed a pivotal role of Cytoplasmic thioredoxin reductase 1 (TXNRD1) and Aldo-keto reductase family 1 member C3 (AKR1C3) in the response of the HaCaT cells to high-irradiance blue or red light exposure. Blue or red light exposure affected the viability of keratinocytes, activating a specific oxidative stress response and inducing mitochondrial dysfunction. Our results can help to address the targets for the therapeutic use of light and to develop adequate preventive strategies for skin damage. This in vitro study supports further in vivo investigations of the biological effects of light on human keratinocytes.

Deletion of the endogenous TrkB.T1 receptor isoform restores the number of hippocampal CA1 parvalbumin-positive neurons and rescues long-term potentiation in pre-symptomatic mSOD1(G93A) ALS mice.

Amyotrophic lateral sclerosis (ALS) causes rapidly progressive paralysis and death within 5 years from diagnosis due to degeneration of the motor circuits. However, a significant population of ALS patients also shows cognitive impairments and progressive hippocampal pathology. Likewise, the mutant SOD1(G93A) mouse model of ALS (mSOD1), in addition to loss of spinal motor neurons, displays altered spatial behavior and hippocampal abnormalities including loss of parvalbumin-positive interneurons (PVi) and enhanced long-term potentiation (LTP). However, the cellular and molecular mechanisms underlying these morpho-functional features are not well understood. Since removal of TrkB.T1, a receptor isoform of the brain-derived neurotrophic factor, can partially rescue the phenotype of the mSOD1 mice, here we tested whether removal of TrkB.T1 can normalize the number of PVi and the LTP in this model. Stereological analysis of hippocampal PVi in control, TrkB.T1-/-, mSOD1, and mSOD1 mice deficient for TrkB.T1 (mSOD1/T1-/-) showed that deletion of TrkB.T1 restored the number of PVi to physiological level in the mSOD1 hippocampus. The rescue of PVi neuron number is paralleled by a normalization of high-frequency stimulation-induced LTP in the pre-symptomatic mSOD1/T1-/- mice. Our experiments identified TrkB.T1 as a cellular player involved in the homeostasis of parvalbumin expressing interneurons and, in the context of murine ALS, show that TrkB.T1 is involved in the mechanism underlying structural and functional hippocampal degeneration. These findings have potential implications for hippocampal degeneration and cognitive impairments reported in ALS patients at early stages of the disease.

Tamalin is a critical mediator of electroconvulsive shock-induced adult neuroplasticity.

The molecular mechanisms underlying the effects of electroconvulsive shock (ECS) therapy, a fast-acting and very effective antidepressant therapy, are poorly understood. Changes related to neuroplasticity, including enhanced adult hippocampal neurogenesis and neuronal arborization, are believed to play an important role in mediating the effects of ECS. Here we show a dynamic upregulation of the scaffold protein tamalin, selectively in the hippocampus of animals subjected to ECS. Interestingly, this gene upregulation is functionally significant because tamalin deletion in mice abrogated ECS-induced neurogenesis in the adult mouse hippocampus. Furthermore, loss of tamalin blunts mossy fiber sprouting and dendritic arborization caused by ECS. These data suggest an essential role for tamalin in ECS-induced adult neuroplasticity and provide new insight into the pathways that are involved in mediating ECS effects.

Senescent Endothelial Cells Sustain Their Senescence-Associated Secretory Phenotype (SASP) through Enhanced Fatty Acid Oxidation.

Cellular senescence is closely linked to endothelial dysfunction, a key factor in age-related vascular diseases. Senescent endothelial cells exhibit a proinflammatory phenotype known as SASP, leading to chronic inflammation (inflammaging) and vascular impairments. Albeit in a state of permanent growth arrest, senescent cells paradoxically display a high metabolic activity. The relationship between metabolism and inflammation is complex and varies across cell types and senescence inductions. While some cell types shift towards glycolysis during senescence, others favor oxidative phosphorylation (OXPHOS). Despite the high availability of oxygen, quiescent endothelial cells (ECs) tend to rely on glycolysis for their bioenergetic needs. However, there are limited data on the metabolic behavior of senescent ECs. Here, we characterized the metabolic profiles of young and senescent human umbilical vein endothelial cells (HUVECs) to establish a possible link between the metabolic status and the proinflammatory phenotype of senescent ECs. Senescent ECs internalize a smaller amount of glucose, have a lower glycolytic rate, and produce/release less lactate than younger cells. On the other hand, an increased fatty acid oxidation activity was observed in senescent HUVECs, together with a greater intracellular content of ATP. Interestingly, blockade of glycolysis with 2-deoxy-D-glucose in young cells resulted in enhanced production of proinflammatory cytokines, while the inhibition of carnitine palmitoyltransferase 1 (CPT1), a key rate-limiting enzyme of fatty acid oxidation, ameliorated the SASP in senescent ECs. In summary, metabolic changes in senescent ECs are complex, and this research seeks to uncover potential strategies for modulating these metabolic pathways to influence the SASP.

Genetic deletion of trkB.T1 increases neuromuscular function.

Neurotrophin-dependent activation of the tyrosine kinase receptor trkB.FL modulates neuromuscular synapse maintenance and function; however, it is unclear what role the alternative splice variant, truncated trkB (trkB.T1), may have in the peripheral neuromuscular axis. We examined this question in trkB.T1 null mice and demonstrate that in vivo neuromuscular performance and nerve-evoked muscle tension are significantly increased. In vitro assays indicated that the gain-in-function in trkB.T1(-/-) animals resulted specifically from an increased muscle contractility, and increased electrically evoked calcium release. In the trkB.T1 null muscle, we identified an increase in Akt activation in resting muscle as well as a significant increase in trkB.FL and Akt activation in response to contractile activity. On the basis of these findings, we conclude that the trkB signaling pathway might represent a novel target for intervention across diseases characterized by deficits in neuromuscular function.

TrkA-cholinergic signaling modulates fear encoding and extinction learning in PTSD-like behavior.

Recent studies have suggested that the use of cognitive enhancers as adjuncts to exposure-based therapy in individuals suffering from post-traumatic stress disorder (PTSD) may be beneficial. Brain cholinergic signaling through basal forebrain projections to the hippocampus is an established pathway mediating fear response and cognitive flexibility. Here we employed a genetic strategy to enhance cholinergic activity through increased signaling of the NGF receptor TrkA. This strategy leads to increased levels of the marker of cholinergic activation, acetylcholine synthesizing enzyme choline acetyltransferase, in forebrain cholinergic regions and their projection areas such as the hippocampus. Mice with increased cholinergic activity do not display any neurobehavioral abnormalities except a selective attenuation of fear response and lower fear expression in extinction trials. Reduction in fear response is rescued by the GABA antagonist picrotoxin in mutant mice, and, in wild-type mice, is mimicked by the GABA agonist midazolam suggesting that GABA can modulate cholinergic functions on fear circuitries. Importantly, mutant mice also show a reduction in fear processing under stress conditions in a single prolonged stress (SPS) model of PTSD-like behavior, and augmentation of cholinergic signaling by the drug donepezil in wild-type mice promotes extinction learning in a similar SPS model of PTSD-like behavior. Donepezil is already in clinical use for the treatment of dementia suggesting a new translational application of this drug for improving exposure-based psychotherapy in PTSD patients.

A distinct hypothalamus-to-ß cell circuit modulates insulin secretion.

The central nervous system has long been thought to regulate insulin secretion, an essential process in the maintenance of blood glucose levels. However, the anatomical and functional connections between the brain and insulin-producing pancreatic ß cells remain undefined. Here, we describe a functional transneuronal circuit connecting the hypothalamus to ß cells in mice. This circuit originates from a subpopulation of oxytocin neurons in the paraventricular hypothalamic nucleus (PVNOXT), and it reaches the islets of the endocrine pancreas via the sympathetic autonomic branch to innervate ß cells. Stimulation of PVNOXT neurons rapidly suppresses insulin secretion and causes hyperglycemia. Conversely, silencing of these neurons elevates insulin levels by dysregulating neuronal signaling and secretory pathways in ß cells and induces hypoglycemia. PVNOXT neuronal activity is triggered by glucoprivation. Our findings reveal that a subset of PVNOXT neurons form functional multisynaptic circuits with ß cells in mice to regulate insulin secretion, and their function is necessary for the ß cell response to hypoglycemia.

Force-feeding malignant mesothelioma stem-cell like with exosome-delivered miR-126 induces tumour cell killing.

Malignant pleural mesothelioma (MPM) is an aggressive tumour resistant to treatments. It has been postulated that cancer stem cells (CSCs) persist in tumours causing relapse after multimodality treatment. In the present study, a novel miRNA-based therapy approach is proposed. MPM-derived spheroids have been treated with exosome-delivered miR-126 (exo-miR) and evaluated for their anticancer effect. The exo-miR treatment increased MPM stem-cell like stemness and inhibited cell proliferation. However, at a prolonged time, the up taken miR-126 was released by the cells themselves through exosomes; the inhibition of exosome release by an exosome release inhibitor GW4869 induced miR-126 intracellular accumulation leading to massive cell death and in vivo tumour growth arrest. Autophagy is involved in these processes; miR-126 accumulation induced a protective autophagy and the inhibition of this process by GW4869 generates a metabolic crisis that promotes necroptosis, which was associated with PARP-1 over-expression and cyt-c and AIF release. Here, for the first time, we proposed a therapy against CSCs, a heterogeneous cell population involved in cancer development and relapse.

Delayed onset of inherited ALS by deletion of the BDNF receptor TrkB.T1 is non-cell autonomous.

The pathophysiology of Amyotrophic Lateral Sclerosis (ALS), a disease caused by the gradual degeneration of motoneurons, is still largely unknown. Insufficient neurotrophic support has been cited as one of the causes of motoneuron cell death. Neurotrophic factors such as BDNF have been evaluated in ALS human clinical trials, but yielded disappointing results attributed to the poor pharmacokinetics and pharmacodynamics of BDNF. In the inherited ALS G93A SOD1 animal model, deletion of the BDNF receptor TrkB.T1 delays spinal cord motoneuron cell death and muscle weakness through an unknown cellular mechanism. Here we show that TrkB.T1 is expressed ubiquitously in the spinal cord and its deletion does not change the SOD1 mutant spinal cord inflammatory state suggesting that TrkB.T1 does not influence microglia or astrocyte activation. Although TrkB.T1 knockout in astrocytes preserves muscle strength and co-ordination at early stages of disease, its specific conditional deletion in motoneurons or astrocytes does not delay motoneuron cell death during the early stage of the disease. These data suggest that TrkB.T1 may limit the neuroprotective BDNF signaling to motoneurons via a non-cell autonomous mechanism providing new understanding into the reasons for past clinical failures and insights into the design of future clinical trials employing TrkB agonists in ALS.

ß-Arrestin-1 is required for adaptive ß-cell mass expansion during obesity.

Obesity is the key driver of peripheral insulin resistance, one of the key features of type 2 diabetes (T2D). In insulin-resistant individuals, the expansion of beta-cell mass is able to delay or even prevent the onset of overt T2D. Here, we report that beta-arrestin-1 (barr1), an intracellular protein known to regulate signaling through G protein-coupled receptors, is essential for beta-cell replication and function in insulin-resistant mice maintained on an obesogenic diet. Specifically, insulin-resistant beta-cell-specific barr1 knockout mice display marked reductions in beta-cell mass and the rate of beta-cell proliferation, associated with pronounced impairments in glucose homeostasis. Mechanistic studies suggest that the observed metabolic deficits are due to reduced Pdx1 expression levels caused by beta-cell barr1 deficiency. These findings indicate that strategies aimed at enhancing barr1 activity and/or expression in beta-cells may prove useful to restore proper glucose homeostasis in T2D.

Endogenous truncated TrkB.T1 receptor regulates neuronal complexity and TrkB kinase receptor function in vivo.

Pathological or in vitro overexpression of the truncated TrkB (TrkB.T1) receptor inhibits signaling through the full-length TrkB (TrkB.FL) tyrosine kinase receptor. However, to date, the role of endogenous TrkB.T1 is still unknown. By studying mice lacking the truncated TrkB.T1 isoform but retaining normal spatiotemporal expression of TrkB.FL, we have analyzed TrkB.T1-specific physiological functions and its effect on endogenous TrkB kinase signaling in vivo. We found that TrkB.T1-deficient mice develop normally but show increased anxiety in association with morphological abnormalities in the length and complexity of neurites of neurons in the basolateral amygdala. However, no behavioral abnormalities were detected in hippocampal-dependent memory tasks, which correlated with lack of any obvious hippocampal morphological deficits or alterations in basal synaptic transmission and long-term potentiation. In vivo reduction of TrkB signaling by removal of one BDNF allele could be partially rescued by TrkB.T1 deletion, which was revealed by an amelioration of the enhanced aggression and weight gain associated with BDNF haploinsufficiency. Our results suggest that, at the physiological level, TrkB.T1 receptors are important regulators of TrkB.FL signaling in vivo. Moreover, TrkB.T1 selectively affects dendrite complexity of certain neuronal populations.

Generation of Functional Mouse Hippocampal Neurons.

Primary culture of mouse hippocampal neurons is a very useful in vitro model for studying neuronal development, axonal and dendritic morphology, synaptic functions, and many other neuronal features. Here we describe a step-by-step process of generating primary neurons from mouse embryonic hippocampi (E17.5/E18.5). Hippocampal neurons generated with this protocol can be plated in different tissue culture dishes according to different experimental aims and can produce a reliable source of pure and differentiated neurons in less than one week. This protocol covers all the steps necessary for the preparation, culture and characterization of the neuronal culture, including the illustration of dissection instruments, surgical procedure for embryos' isolation, culturing conditions and assessment of culture's purity and differentiation. Evaluation of neuronal activity was performed by analysis of calcium imaging dynamics at six days in culture.

Mapping Single Walled Carbon Nanotubes in Photosynthetic Algae by Single-Cell Confocal Raman Microscopy.

Carbon nanotubes (CNTs) are among the most exploited carbon allotropes in the emerging technologies of molecular sensing and bioengineering. However, the advancement of algal nanobiotechnology and nanobionics is hindered by the lack of methods for the straightforward visualization of the CNTs inside the cell. Herein, we present a handy and label-free experimental strategy based on visible Raman microscopy to assess the internalization of single-walled carbon nanotubes (SWCNTs) using the model photosynthetic alga Chlamydomonas reinhardtii as a recipient. The relationship between the properties of SWCNTs and their biological behavior was demonstrated, along with the occurrence of excitation energy transfer from the excited chlorophyll molecules to the SWCNTs. The non-radiative deactivation of the chlorophyll excitation promoted by the SWCNTs enables the recording of Raman signals originating from cellular compounds located near the nanotubes, such as carotenoids, polyphosphates, and starch. Furthermore, the outcome of this study unveils the possibility to exploit SWCNTs as spectroscopic probes in photosynthetic and non-photosynthetic systems where the fluorescence background hinders the acquisition of Raman scattering signals.

Calcium-induced calcium release and type 3 ryanodine receptors modulate the slow afterhyperpolarising current, sIAHP, and its potentiation in hippocampal pyramidal neurons.

The slow afterhyperpolarising current, sIAHP, is a Ca2+-dependent current that plays an important role in the late phase of spike frequency adaptation. sIAHP is activated by voltage-gated Ca2+ channels, while the contribution of calcium from ryanodine-sensitive intracellular stores, released by calcium-induced calcium release (CICR), is controversial in hippocampal pyramidal neurons. Three types of ryanodine receptors (RyR1-3) are expressed in the hippocampus, with RyR3 showing a predominant expression in CA1 neurons. We investigated the specific role of CICR, and particularly of its RyR3-mediated component, in the regulation of the sIAHP amplitude and time course, and the activity-dependent potentiation of the sIAHP in rat and mouse CA1 pyramidal neurons. Here we report that enhancement of CICR by caffeine led to an increase in sIAHP amplitude, while inhibition of CICR by ryanodine caused a small, but significant reduction of sIAHP. Inhibition of ryanodine-sensitive Ca2+ stores by ryanodine or depletion by the SERCA pump inhibitor cyclopiazonic acid caused a substantial attenuation in the sIAHP activity-dependent potentiation in both rat and mouse CA1 pyramidal neurons. Neurons from mice lacking RyR3 receptors exhibited a sIAHP with features undistinguishable from wild-type neurons, which was similarly reduced by ryanodine. However, the lack of RyR3 receptors led to a faster and reduced activity-dependent potentiation of sIAHP. We conclude that ryanodine receptor-mediated CICR contributes both to the amplitude of the sIAHP at steady state and its activity-dependent potentiation in rat and mouse hippocampal pyramidal neurons. In particular, we show that RyR3 receptors play an essential and specific role in shaping the activity-dependent potentiation of the sIAHP. The modulation of activity-dependent potentiation of sIAHP by RyR3-mediated CICR contributes to plasticity of intrinsic neuronal excitability and is likely to play a critical role in higher cognitive functions, such as learning and memory.

Novel metabolic role for BDNF in pancreatic ß-cell insulin secretion.

BDNF signaling in hypothalamic circuitries regulates mammalian food intake. However, whether BDNF exerts metabolic effects on peripheral organs is currently unknown. Here, we show that the BDNF receptor TrkB.T1 is expressed by pancreatic ß-cells where it regulates insulin release. Mice lacking TrkB.T1 show impaired glucose tolerance and insulin secretion. ß-cell BDNF-TrkB.T1 signaling triggers calcium release from intracellular stores, increasing glucose-induced insulin secretion. Additionally, BDNF is secreted by skeletal muscle and muscle-specific BDNF knockout phenocopies the ß-cell TrkB.T1 deletion metabolic impairments. The finding that BDNF is also secreted by differentiated human muscle cells and induces insulin secretion in human islets via TrkB.T1 identifies a new regulatory function of BDNF on metabolism that is independent of CNS activity. Our data suggest that muscle-derived BDNF may be a key factor mediating increased glucose metabolism in response to exercise, with implications for the treatment of diabetes and related metabolic diseases.

Small extracellular vesicles deliver miR-21 and miR-217 as pro-senescence effectors to endothelial cells.

The role of epigenetics in endothelial cell senescence is a cutting-edge topic in ageing research. However, little is known of the relative contribution to pro-senescence signal propagation provided by microRNAs shuttled by extracellular vesicles (EVs) released from senescent cells. Analysis of microRNA and DNA methylation profiles in non-senescent (control) and senescent (SEN) human umbilical vein endothelial cells (HUVECs), and microRNA profiling of their cognate small EVs (sEVs) and large EVs demonstrated that SEN cells released a significantly greater sEV number than control cells. sEVs were enriched in miR-21-5p and miR-217, which target DNMT1 and SIRT1. Treatment of control cells with SEN sEVs induced a miR-21/miR-217-related impairment of DNMT1-SIRT1 expression, the reduction of proliferation markers, the acquisition of a senescent phenotype and a partial demethylation of the locus encoding for miR-21. MicroRNA profiling of sEVs from plasma of healthy subjects aged 40-100 years showed an inverse U-shaped age-related trend for miR-21-5p, consistent with senescence-associated biomarker profiles. Our findings suggest that miR-21-5p/miR-217 carried by SEN sEVs spread pro-senescence signals, affecting DNA methylation and cell replication.

Parvalbumin-positive GABAergic interneurons are increased in the dorsal hippocampus of the dystrophic mdx mouse.

Duchenne muscular dystrophy (DMD) is characterized by variable alterations of the dystrophin gene and by muscle weakness and cognitive impairment. We postulated an association between cognitive impairment and architectural changes of the hippocampal GABAergic system. We investigated a major subpopulation of GABAergic neurons, the parvalbumin-immunopositive (PV-I) cells, in the dorsal hippocampus of the mdx mouse, an acknowledged model of DMD. PV-I neurons were quantified and their distribution was compared in CA1, CA2, CA3, and dentate gyrus in wild-type and mdx mice. The cell morphology and topography of PV-I neurons were maintained. Conversely, the number of PV-I neurons was significantly increased in the mdx mouse. The percent increase of PV-I neurons was from 45% for CA2, up to 125% for the dentate gyrus. In addition, the increased parvalbumin content in the mdx hippocampus was confirmed by Western blot. A change in the hippocampus processing abilities is the expected functional counterpart of the modification displayed by PV-I GABAergic neurons. Altered hippocampal functionality can be responsible for part of the cognitive impairment in DMD.

Mesenchymal Stem Cells from Nucleus Pulposus and Neural Differentiation Potential: a Continuous Challenge.

Mesenchymal stem cells (MSCs) are well-characterized adult stem cells, recently isolated from human nucleus pulposus of degenerate and non-degenerate intervertebral disc. The attention to this source is linked to its embryologic history and cells may conserve a stronger aptitude to neuronal differentiation than other MSCs. Here, MSCs from nucleus pulposus (NP-MSCs) were successfully isolated and characterized for morphology, proliferation, and expression of selected genes. Subsequently, the neuronal differentiation was induced by 10 days of culture with a neuronal medium. NP-MSCs subjected to neural differentiation media (NP-MSCs-N) showed a morphological and biochemical modifications. NP-MSCs-N displayed elongated shape with protrusion, intermediate filaments, microtubules, and electron dense granules and the ability to form neurospheres. Even if they expressed neural markers such as NESTIN, ß-TUBULIN III, MAP-2, GAP-43, and ENOLASE-2, the neural differentiated cells did not show neither spontaneous nor evoked intracellular calcium variations compared to the undifferentiated cells, suggesting that cells do not have electric functional properties. Further studies are required in order to get a better understanding and characterization of NP-MSCs and analyzed the molecular mechanisms that regulate their neural differentiation potential.