A population of human brain cells expressing phenotypic markers of more than one lineage can be induced in vitro to differentiate into mesenchymal cells

Integrated Metabolomics and Lipidomics Reveal High Accumulation of Glycerophospholipids in Human Astrocytes under the Lipotoxic Effect of Palmitic Acid and Tibolone Protection

Lipotoxicity is a metabolic condition resulting from the accumulation of free fatty acids in non-adipose tissues which involves a series of pathological responses triggered after chronic exposure to high levels of fatty acids, severely detrimental to cellular homeostasis and viability. In brain, lipotoxicity affects both neurons and other cell types, notably astrocytes, leading to neurodegenerative processes, such as Alzheimer (AD) and Parkinson diseases (PD). In this study, we performed for the first time, a whole lipidomic characterization of Normal Human Astrocytes cultures exposed to toxic concentrations of palmitic acid and the protective compound tibolone, to establish and identify the set of potential metabolites that are modulated under these experimental treatments. The study covered 3843 features involved in the exo- and endo-metabolome extracts obtained from astrocytes with the mentioned treatments. Through multivariate statistical analysis such as PCA (principal component analysis), partial least squares (PLS-DA), clustering analysis, and machine learning enrichment analysis, it was possible to determine the specific metabolites that were affected by palmitic acid insult, such as phosphoethanolamines, phosphoserines phosphocholines and glycerophosphocholines, with their respective metabolic pathways impact. Moreover, our results suggest the importance of tibolone in the generation of neuroprotective metabolites by astrocytes and may be relevant to the development of neurodegenerative processes.

SOX2 and SOX2-MYC Reprogramming Process of Fibroblasts to the Neural Stem Cells Compromised by Senescence

Tumorigenic potential of induced pluripotent stem cells (iPSCs) infiltrating population of induced neural stem cells (iNSCs) generated from iPSCs may limit their medical applications. To overcome such a difficulty, direct reprogramming of adult somatic cells into iNSCs was proposed. The aim of this study was the systematic comparison of induced neural cells (iNc) obtained with different methods—direct reprogramming of human adult fibroblasts with either SOX2 (SiNSc-like) or SOX2 and c-MYC (SMiNSc-like) and induced pluripotent stem cells differentiation to ebiNSc—in terms of gene expression profile, differentiation potential as well as proliferation properties. Immunocytochemistry and real-time PCR analyses were used to evaluate gene expression profile and differentiation potential of various iNc types. Bromodeoxyuridine (BrdU) incorporation and senescence-associated beta-galactosidase (SA-β-gal) assays were used to estimate proliferation potential. All three types of iNc were capable of neuronal differentiation; however, astrocytic differentiation was possible only in case of ebiNSc. Contrary to ebiNSc generation, the direct reprogramming was rarely a propitious process, despite 100% transduction efficiency. The potency of direct iNSCs-like cells generation was lower as compared to iNSCs obtained by iPSCs differentiation, and only slightly improved when c-MYC was added. Directly reprogrammed iNSCs-like cells were lacking the ability to differentiate into astrocytic cells and characterized by poor efficiency of neuronal cells formation. Such features indicated that these cells could not be fully reprogrammed, as confirmed mainly with senescence detection. Importantly, SiNSc-like and SMiNSc-like cells were unable to achieve the long-term survival and became senescent, which limits their possible therapeutic applicability. Our results suggest that iNSCs-like cells, generated in the direct reprogramming attempts, were either not fully reprogrammed or reprogrammed only into neuronal progenitors, mainly because of the inaccuracies of currently available protocols.

Fibronectin is a potential cerebrospinal fluid and serum epilepsy biomarker

PURPOSE

Previous studies have demonstrated that fibronectin (FN) levels are increased in brain tissues from patients and animals with epilepsy. This study aimed to assess FN levels in cerebrospinal fluid (CSF) and serum samples from patients with epilepsy.

METHODS

Fibronectin levels were assessed in CSF and serum samples from 56 patients with epilepsy (27 and 29 individuals with intractable epilepsy and nonintractable epilepsy, respectively) and 25 healthy controls, using sandwich enzyme-linked immunosorbent assays (ELISA).

RESULTS

CSF-FN levels were higher in patients with epilepsy (8.07 ± 1.51 mg/l versus 6.20 ± 1.18 mg/l, p<0.05) than in the control group. In addition, serum-FN levels in the group with epilepsy and in the control group were 236.96 ± 65.7 mg/l and 181.43 ± 72.82 mg/l, respectively, indicating a statistically significant difference (p=0.01). Interestingly, serum- and CSF-FN levels in individuals with epilepsy were not affected by antiepileptic drug and duration of epilepsy. Of note, the increase of CSF- and serum-FN levels was more pronounced in subjects with intractable epilepsy than in patients with nonintractable epilepsy.

CONCLUSION

Serum- and CSF-FN levels constitute a potential clinical diagnostic biomarker for epilepsy and could also be used for differential diagnosis.

Plasticity of mesenchymal stem cells from mouse bone marrow in the presence of conditioned medium of the facial nerve and fibroblast growth factor-2

A number of evidences show the influence of the growth of injured nerve fibers in peripheral nervous system as well as potential implant stem cells (SCs). The SCs implementation in the clinical field is promising and the understanding of proliferation and differentiation is essential. This study aimed to evaluate the plasticity of mesenchymal SCs from bone marrow of mice in the presence of culture medium conditioned with facial nerve explants and fibroblast growth factor-2 (FGF-2). The growth and morphology were assessed for over 72 hours. Quantitative phenotypic analysis was taken from the immunocytochemistry for glial fibrillary acidic protein (GFAP), protein OX-42 (OX-42), protein associated with microtubule MAP-2 (MAP-2), protein β-tubulin III (β-tubulin III), neuronal nuclear protein (NeuN), and neurofilament 200 (NF-200). Cells cultured with conditioned medium alone or combined with FGF-2 showed morphological features apparently similar at certain times to neurons and glia and a significant proliferative activity in groups 2 and 4. Cells cultivated only with conditioned medium acquired a glial phenotype. Cells cultured with FGF-2 and conditioned medium expressed GFAP, OX-42, MAP-2, β-tubulin III, NeuN, and NF-200. This study improves our understanding of the plasticity of mesenchymal cells and allows the search for better techniques with SCs.

Neuroprotective role of fibronectin in neuron-glial extrasynaptic transmission

Most hypotheses concerning the mechanisms underlying Parkinson's disease are based on altered synaptic transmission of the nigrostriatal system. However, extrasynaptic transmission was recently found to affect dopamine neurotransmitter delivery by anisotropic diffusion in the extracellular matrix, which is modulated by various extracellular matrix components such as fibronectin. The present study reviewed the neuroprotective effect of fibronectin in extrasynaptic transmission. Fibronectin can regulate neuroactive substance diffusion and receptor activation, and exert anti- neuroinflammatory, adhesive and neuroprotective roles. Fibronectin can bind to integrin and growth factor receptors to transactivate intracellular signaling events such as the phosphatidylinositol 3-kinase/protein kinase B pathway to regulate or amplify growth factor-like neuroprotective actions. Fibronectin is assembled into a fibrillar network around cells to facilitate cell migration, molecule and ion diffusion, and even drug delivery and treatment. In addition, the present study analyzed the neuroprotective mechanism of fibronectin in the pathogenesis of Parkinson's disease, involving integrin and growth factor receptor interactions, and discussed the possible therapeutic and diagnostic significance of fibronectin in Parkinson's disease.

Isolation of multilineage progenitors from mouse brain

Stem cells are unique cell populations with the ability to undergo self-renewal and differentiation. These cells have been identified in a wide range of tissues and possess varied differentiation potentials. Tissue-specific stem cells have typically been thought to have limited differentiation capabilities. We show here that fibroblast-like cells isolated from mouse brain possess cross-germ layer differentiation abilities. These cells were found to express typical mesenchymal stem cell markers (CD44, CD29, and CD105) and were able to be passaged more than 50 times. When treated under defined conditions, the brain-derived cells were able to generate many different cell types including adipocytes, osteocytes, astrocytes, neurons, and even hepatocyte-like cells. The hepatocyte-like cells not only expressed liver cell-specific markers, but also exhibited the capacity for glycogen storage and low-density lipoprotein uptake. These results demonstrate the existence of cells in the brain with three-germ-layer differentiation potential.

Differentiation capacity of native pituitary folliculostellate cells and brain astrocytes

Pituitary folliculostellate (FS) cells are characterized by producing S100B protein, as do brain astrocytes. FS cells have some functions in the pituitary gland, i.e. scavenger functions, sustentacular cell activity through cytokines, and intercellular communication through gap junctions. However, the biological significances of FS cells, especially their differentiation capacities in the anterior pituitary gland, are still under discussion. To understand FS cells with new approaches, we generated a transgenic rat expressing GFP under S100b gene promoter, which regulates tissue-specific expression of S100b gene. Using the transgenic rat, we succeeded in inducing skeletal muscle cells from FS cells by culturing it in serum-free medium containing B-27 supplement, thyroid hormone (tri-iodothyronine), epidermal growth factor, and basic fibroblast growth factor. In this study, we also succeeded in inducing skeletal muscle cells from primary cultured astrocytes and astrocyte cell line, C6 cells. Hence, we concluded that pituitary FS cells have wide differentiation potential and have similar characteristics to astrocytes, which not only support cell activity but also support differentiation capacity.

Bone-marrow-derived mesenchymal stem cell therapy for neurodegenerative diseases

BACKGROUND

Stem-cell-based therapy is a promising new approach to handling neurodegenerative diseases. One of the most promising cellular sources is bone-marrow-derived mesenchymal stem cells (MSCs) also termed multipotent stromal cells. MSCs represent an autologous source and are abundant and non-tumorigenic. Additionally, MSCs possess the useful characteristics of homing and chemokine secretion.

OBJECTIVE/METHODS

Since neurodegenerative diseases have many pathological processes in common, a specific therapeutic agent could potentially ameliorate the symptoms of several distinct neurodegenerative diseases. In this review we demonstrate the wide variety of mechanisms by which MSCs can influence neurodegenerative processes.

RESULTS/CONCLUSIONS

The mechanisms by which transplanted MSCs influence neurodegenerative diseases can be broadly classified as cellular replacement or paracrine secretion, with the latter subdivided into trophic factor secretion or immunomodulation by cytokines. Emerging research suggests that genetic manipulations before transplantation could enhance the therapeutic potential of MSCs. Such manipulation could turn the cells into a 'Trojan horse', to deliver specific proteins, or promote reprogramming of the MSCs into the neural lineage. Clinical trials testing MSC-based therapies for familial amyotrophic lateral sclerosis and multiple sclerosis are in progress.

Arrested neural and advanced mesenchymal differentiation of glioblastoma cells-comparative study with neural progenitors

BACKGROUND

Although features of variable differentiation in glioblastoma cell cultures have been reported, a comparative analysis of differentiation properties of normal neural GFAP positive progenitors, and those shown by glioblastoma cells, has not been performed.

METHODS

Following methods were used to compare glioblastoma cells and GFAP+NNP (NHA): exposure to neural differentiation medium, exposure to adipogenic and osteogenic medium, western blot analysis, immunocytochemistry, single cell assay, BrdU incorporation assay. To characterize glioblastoma cells EGFR amplification analysis, LOH/MSI analysis, and P53 nucleotide sequence analysis were performed.

RESULTS

In vitro differentiation of cancer cells derived from eight glioblastomas was compared with GFAP-positive normal neural progenitors (GFAP+NNP). Prior to exposure to differentiation medium, both types of cells showed similar multilineage phenotype (CD44+/MAP2+/GFAP+/Vimentin+/Beta III-tubulin+/Fibronectin+) and were positive for SOX-2 and Nestin. In contrast to GFAP+NNP, an efficient differentiation arrest was observed in all cell lines isolated from glioblastomas. Nevertheless, a subpopulation of cells isolated from four glioblastomas differentiated after serum-starvation with varying efficiency into derivatives indistinguishable from the neural derivatives of GFAP+NNP. Moreover, the cells derived from a majority of glioblastomas (7 out of 8), as well as GFAP+NNP, showed features of mesenchymal differentiation when exposed to medium with serum.

CONCLUSION

Our results showed that stable co-expression of multilineage markers by glioblastoma cells resulted from differentiation arrest. According to our data up to 95% of glioblastoma cells can present in vitro multilineage phenotype. The mesenchymal differentiation of glioblastoma cells is advanced and similar to mesenchymal differentiation of normal neural progenitors GFAP+NNP.