Mesenchymal stem cells (MSCs) can trans/differentiate to neural precursors and/or mature neurons and promote neuroprotection and neurogenesis. The above could greatly benefit neurodegenerative ...disorders as well as in the treatment of post-traumatic and hereditary diseases of the central nervous system (CNS). In order to attain an ideal source of adult MSCs for the treatment of CNS diseases, adipose tissue, bone marrow, skin and umbilical cord derived MSCs were isolated and studied to explore differences with regard to neural differentiation capacity. In this study, we demonstrated that MSCs from several tissues can differentiate into neuron-like cells and differentially express progenitors and mature neural markers. Adipose tissue MSCs exhibited significantly higher expression of neural markers and had a faster proliferation rate. Our results suggest that adipose tissue MSCs are the best candidates for the use in neurological diseases.
It has been postulated that the accumulation of extracellular α‐synuclein (α‐syn) might alter the neuronal membrane by formation of ‘pore‐like structures’ that will lead to alterations in ionic ...homeostasis. However, this has never been demonstrated to occur in brain neuronal plasma membranes. In this study, we show that α‐syn oligomers rapidly associate with hippocampal membranes in a punctate fashion, resulting in increased membrane conductance (5 fold over control) and the influx of both calcium and a fluorescent glucose analogue. The enhancement in intracellular calcium (1.7 fold over control) caused a large increase in the frequency of synaptic transmission (2.5 fold over control), calcium transients (3 fold over control), and synaptic vesicle release. Both primary hippocampal and dissociated nigral neurons showed rapid increases in membrane conductance by α‐syn oligomers. In addition, we show here that α‐syn caused synaptotoxic failure associated with a decrease in SV2, a membrane protein of synaptic vesicles associated with neurotransmitter release. In conclusion, extracellular α‐syn oligomers facilitate the perforation of the neuronal plasma membrane, thus explaining, in part, the synaptotoxicity observed in neurodegenerative diseases characterized by its extracellular accumulation.
We propose that α‐synuclein (α‐syn) oligomers form pore‐like structures in the plasma membrane of neurons from central nervous system (CNS). We believe that extracellular α‐syn oligomers facilitate the formation of α‐syn membrane pore‐like structures, thus explaining, in part, the synaptotoxicity observed in neurodegenerative diseases characterized by its extracellular accumulation. We think that alterations in ionic homeostasis and synaptic vesicular depletion are key steps that lead to synaptotoxicity promoted by α ‐syn membrane pore‐like structures.
We propose that α‐synuclein (α‐syn) oligomers form pore‐like structures in the plasma membrane of neurons from central nervous system (CNS). We believe that extracellular α‐syn oligomers facilitate the formation of α‐syn membrane pore‐like structures, thus explaining, in part, the synaptotoxicity observed in neurodegenerative diseases characterized by its extracellular accumulation. We think that alterations in ionic homeostasis and synaptic vesicular depletion are key steps that lead to synaptotoxicity promoted by α ‐syn membrane pore‐like structures.
Read the Editorial Highlight for this article on page 619.
Dysferlinopathy is an autosomal recessive muscular dystrophy resulting from mutations in the dysferlin gene. Absence of dysferlin in the sarcolemma and progressive muscle wasting are hallmarks of ...this disease. Signs of oxidative stress have been observed in skeletal muscles of dysferlinopathy patients, as well as in dysferlin-deficient mice. However, the contribution of the redox imbalance to this pathology and the efficacy of antioxidant therapy remain unclear. Here, we evaluated the effect of 10 weeks diet supplementation with the antioxidant agent
-acetylcysteine (NAC, 1%) on measurements of oxidative damage, antioxidant enzymes, grip strength and body mass in 6 months-old dysferlin-deficient Bla/J mice and wild-type (WT) C57 BL/6 mice. We found that quadriceps and gastrocnemius muscles of Bla/J mice exhibit high levels of lipid peroxidation, protein carbonyls and superoxide dismutase and catalase activities, which were significantly reduced by NAC supplementation. By using the Kondziela's inverted screen test, we further demonstrated that NAC improved grip strength in dysferlin deficient animals, as compared with non-treated Bla/J mice, without affecting body mass. Together, these results indicate that this antioxidant agent improves skeletal muscle oxidative balance, as well as muscle strength and/or resistance to fatigue in dysferlin-deficient animals.
Dynamin-2 is a ubiquitously expressed GTP-ase that mediates membrane remodeling. Recent findings indicate that dynamin-2 also regulates actin dynamics. Mutations in dynamin-2 cause dominant ...centronuclear myopathy (CNM), a congenital myopathy characterized by progressive weakness and atrophy of skeletal muscles. However, the muscle-specific roles of dynamin-2 affected by these mutations remain elusive. Here we show that, in muscle cells, the GTP-ase activity of dynamin-2 is involved in de novo actin polymerization as well as in actin-mediated trafficking of the glucose transporter GLUT4. Expression of dynamin-2 constructs carrying CNM-linked mutations disrupted the formation of new actin filaments as well as the stimulus-induced translocation of GLUT4 to the plasma membrane. Similarly, mature muscle fibers isolated from heterozygous knock-in mice that harbor the dynamin-2 mutation p.R465W, an animal model of CNM, exhibited altered actin organization, reduced actin polymerization and impaired insulin-induced translocation of GLUT4 to the sarcolemma. Moreover, GLUT4 displayed aberrant perinuclear accumulation in biopsies from CNM patients carrying dynamin-2 mutations, further suggesting trafficking defects. These results suggest that dynamin-2 is a key regulator of actin dynamics and GLUT4 trafficking in muscle cells. Our findings also support a model in which impairment of actin-dependent trafficking contributes to the pathological mechanism in dynamin-2-associated CNM.
In type I diabetes mellitus (T1DM) pancreatic β cells are destroyed. Treatment entails exogenous insulin administration and strict diet control, yet optimal glycemic control is hardly attainable. ...Islet transplant could be an alternative in patients with poor glycemic control, but inefficient islet purification and autoimmune response of patients is still a challenge. For these reasons, it is necessary to explore new cellular sources and immunological isolation methods oriented to develop T1DM cell-based therapies.
We postulate human adipose-derived stem cell (hASC) as an adequate source to generate pancreatic islet cells in vitro, and to produce islet-like structures. Furthermore, we propose microencapsulation of these aggregates as an immunological isolation strategy.
hASC obtained from lipoaspirated fat tissue from human donors were differentiated in vitro to insulin (Ins) and glucagon (Gcg) producing cells. Then, insulin producing cells (IPC) and glucagon producing cells (GPC) were cocultured in low adhesion conditions to form cellular aggregates, and later encapsulated in a sodium alginate polymer. Expression of pancreatic lineage markers and secretion of insulin or glucagon in vitro were analyzed.
The results show that multipotent hASC efficiently differentiate to IPC and GPC, and express pancreatic markers, including insulin or glucagon hormones which they secrete upon stimulation (fivefold for insulin in IPC, and fourfold for glucagon, compared to undifferentiated cells). In turn, calculation of the Feret diameter and area of cellular aggregates revealed mean diameters of ~ 80 µm, and 65% of the aggregates reached 4000 µm
at 72 h of formation. IPC/GPC aggregates were then microencapsulated in sodium-alginate polymer microgels, which were found to be more stable when stabilized with Ba
, yielding average diameters of ~ 300 µm. Interestingly, Ba
-microencapsulated aggregates respond to high external glucose with insulin secretion.
The IPC/GPC differentiation process from hASC, followed by the generation of cellular aggregates that are later microencapsulated, could represent a possible treatment for T1DM.
Dynamin‐2 in nervous system disorders González‐Jamett, Arlek M.; Haro‐Acuña, Valentina; Momboisse, Fanny ...
Journal of neurochemistry,
January 2014, Letnik:
128, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Dynamin‐2 is a pleiotropic GTPase whose best‐known function is related to membrane scission during vesicle budding from the plasma or Golgi membranes. In the nervous system, dynamin‐2 participates in ...synaptic vesicle recycling, post‐synaptic receptor internalization, neurosecretion, and neuronal process extension. Some of these functions are shared with the other two dynamin isoforms. However, the involvement of dynamin‐2 in neurological illnesses points to a critical function of this isoform in the nervous system. In this regard, mutations in the dynamin‐2 gene results in two congenital neuromuscular disorders. One of them, Charcot‐Marie‐Tooth disease, affects myelination and peripheral nerve conduction, whereas the other, Centronuclear Myopathy, is characterized by a progressive and generalized atrophy of skeletal muscles, yet it is also associated with abnormalities in the nervous system. Furthermore, single nucleotide polymorphisms located in the dynamin‐2 gene have been associated with sporadic Alzheimer's disease. In the present review, we discuss the pathogenic mechanisms implicated in these neurological disorders.
Disease‐linked dynamin‐2 mutations are mainly located in the middle and pleckstrin homology (PH) domains. (a) Dynamin is a multimodular enzyme comprising five highly conserved structural domains: a N‐terminal GTPase domain (G‐domain) required for binding and hydrolysis of GTP, a middle domain, a PH domain that mediates lipid interaction, a GTPase effector domain (GED) that regulates GTPase activity, which together with the middle domain is involved in dynamin oligomerization. Finally, a C‐terminal proline rich domain (PRD) is present, which is required for interaction with SH3‐domain‐containing proteins. (b) A ‘T‐shape’ dimer appears to be the structural unit of dynamin oligomers (Chappie et al. 2011). In this configuration, the PH domains (yellow) of neighboring monomers act as the ‘legs’ that insert dynamin into lipid membranes. Each ‘stalk’ region formed by the middle (green) and GED (red) domains interacts with the other in a crossed fashion, orienting the respective G‐domains (blue) in opposite directions. Most of the mutations identified in CNM‐patients (at the left) localize at the middle and C‐terminal α‐helix PH domains, both of which are implicated in dynamin oligomerization. Most of the CMT‐linked mutations (at the right) clustering at the N‐terminal region of the PH domain are involved in the insertion of dynamin into lipid membranes. Color code for structural domains and letters indicating the mutations are the same as those shown in A. In this diagram, PRD is omitted.
Resumen Introducción y Objetivo: El tejido adiposo es una fuente de células estromales de fácil acceso. Para su almacenamiento y posterior aplicación en clínica es importante que el método de ...criopreservación a utilizar mantenga adecuadas tasas de viabilidad tras un ciclo de congelación. El objetivo del presente trabajo es obtener células estromales humanas derivadas del tejido adiposo, implementar un protocolo de criopreservación libre de proteína animal y medir las tasas de viabilidad posterior a un ciclo de criopreservación para su eventual aplicación clínica. Material y Método: Utilizamos grasa fresca de 5 pacientes sometidas a lipoaspiración y aislamos las células estromales mediante técnicas de digestión enzimática y expansión celular. Realizamos la caracterización de las células mediante inmunofenotipificación. Criopreservamos las células utilizando dimetil-sulfóxido 10% y las almacenamos durante 1 mes en nitrógeno líquido. Evaluamos la tasa de viabilidad mediante ioduro de propidio y citometría de flujo, antes y después de un ciclo de criopreservación. Resultados: Obtuvimos células estromales derivadas del tejido adiposo, confirmado con el panel de inmunofenotipificación. Las tasas de viabilidad promedio obtenidas con ioduro de propidio fue 61.89% mientras que la tasa de mortalidad fue 32.68% tras un ciclo de criopreservación. Conclusiones: Mediante un protocolo de criopreservación utilizando un medio definido con dimetil-sulfóxido 10% en ausencia de proteína animal, es posible obtener tasas aceptables de viabilidad de las células estromales derivadas del tejido adiposo tras un ciclo de criopreservación.
Hereditary myopathies are a group of genetically determined muscle disorders comprising more than 300 entities. In Chile, there are no specific registries of the distinct forms of these myopathies. ...We now report the genetic findings of a series of Chilean patients presenting with limb-girdle muscle weakness of unknown etiology. Eighty-two patients were explored using high-throughput sequencing approaches with neuromuscular gene panels, establishing a definite genetic diagnosis in 49 patients (59.8%) and a highly probable genetic diagnosis in eight additional cases (9.8%). The most frequent causative genes identified were DYSF and CAPN3, accounting for 22% and 8.5% of the cases, respectively, followed by DMD (4.9%) and RYR1 (4.9%). The remaining 17 causative genes were present in one or two cases only. Twelve novel variants were identified. Five patients (6.1%) carried a variant of uncertain significance in genes partially matching the clinical phenotype. Twenty patients (24.4%) did not carry a pathogenic or likely pathogenic variant in the phenotypically related genes, including five patients (6.1%) presenting an autoimmune neuromuscular disorder. The relative frequency of the different forms of myopathy in Chile is like that of other series reported from different regions of the world with perhaps a relatively higher incidence of dysferlinopathy.
Metal doping of bioactive glasses based on ternary 60SiO2-36CaO-4P2O5 (58S) and quaternary 60SiO2-25CaO-11Na2O-4P2O5 (NaBG) mol% compositions synthesized using a sol-gel process was analyzed. In ...particular, the effect of incorporating 1, 5 and 10 mol% of CuO and ZnO (replacing equivalent quantities of CaO) on the texture, in vitro bioactivity, and cytocompatibility of these materials was evaluated. Our results showed that the addition of metal ions can modulate the textural property of the matrix and its crystal structure. Regarding the bioactivity, after soaking in simulated body fluid (SBF) undoped 58S and NaBG glasses developed an apatite surface layer that was reduced in the doped glasses depending on the type of metal and its concentration with Zn displaying the largest inhibitions. Both the ion release from samples and the ion adsorption from the medium depended on the type of matrix with 58S glasses showing the highest values. Pure NaBG glass was more cytocompatible to osteoblast-like cells (SaOS-2) than pure 58S glass as tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The incorporation of metal ions decreased the cytocompatibility of the glasses depending on their concentration and on the glass matrix doped. Our results show that by changing the glass composition and by adding Cu or Zn, bioactive materials with different textures, bioactivity and cytocompatibility can be synthesized.
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