In this study, we focused on age-related changes in astrocyte functioning, predominantly on the ability of astrocytes to regulate their volume in response to a pathological stimulus, namely extracellular 50 mM K+ concentration. The aim of our project was to identify changes in the expression and function of transport proteins in the astrocytic membrane and properties of the extracellular space, triggered by aging. We used three-dimensional confocal morphometry, gene expression profiling, immunohistochemical analysis, and diffusion measurement in the hippocampal slices from 3-, 9-, 12-, and 18-month-old mice, in which astrocytes are visualized by enhanced green fluorescent protein under the control of the promoter for human glial fibrillary acidic protein. Combining a pharmacological approach and the quantification of astrocyte volume changes evoked by hyperkalemia, we found that marked diversity in the extent of astrocyte swelling in the hippocampus during aging is due to the gradually declining participation of Na+-K+-Cl- transporters, glutamate transporters (glutamate aspartate transporter and glutamate transporter 1), and volume-regulated anion channels. Interestingly, there was a redistribution of Na+-K+-Cl- cotransporter and glutamate transporters from astrocytic soma to processes. In addition, immunohistochemical analysis confirmed an age-dependent decrease in the content of Na+-K+-Cl- cotransporter in astrocytes. The overall extracellular volume changes revealed a similar age-dependent diversity during hyperkalemia as observed in astrocytes. In addition, the recovery of the extracellular space was markedly impaired in aged animals.
- MeSH
- astrocyty účinky léků metabolismus patologie fyziologie MeSH
- draslík farmakologie MeSH
- gliový fibrilární kyselý protein MeSH
- hipokampus cytologie MeSH
- myši transgenní MeSH
- stárnutí patologie fyziologie MeSH
- velikost buňky * MeSH
- zelené fluorescenční proteiny MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Small twigs represent a substantial input of organic carbon into forest soils, but potential influencing factors on their decomposition have rarely been investigated. Here, we studied potential effects of twig size on decomposition and associated composition and activity of microbial communities during decomposition. Because the surface area for microbial colonization and the volume of accessible substrate increases with decreasing twig size, we hypothesized that twig size affects both microbial community and decomposition rate. Litterbags with twigs (Salix caprea) of two different diameters were placed within the litter layer and consecutively collected over a seven-year period. We determined the mass loss and microbial measures after each sampling event. The observed microbial parameters suggested a faster microbial colonization of thin twigs, where the proportion of bacteria was higher than in thick twigs. The development of the microbial community in thick twigs was more gradual and the proportion of fungi was higher. Despite this differential and successional development of microbial communities (and against our hypothesis), the mass loss among different twig diameters did not differ after our seven-year experiment, indicating that surface-to-volume ratios, though a primary control on microbial succession, may have limited predictive power for twig decomposition rates.
1. vydání 266 stran : ilustrace ; 21 cm
- MeSH
- bezpečnost MeSH
- ochrana veřejného zdraví MeSH
- prevence úrazů MeSH
- reklama zaměřená na spotřebitele MeSH
- sociální marketing MeSH
- Geografické názvy
- Česká republika MeSH
- Konspekt
- Reklama. Public relations. Média
- NLK Obory
- sociologie
- NLK Publikační typ
- kolektivní monografie
NG2 cells, a fourth glial cell type in the adult mammalian central nervous system, produce oligodendrocytes in the healthy nervous tissue, and display wide differentiation potential under pathological conditions, where they could give rise to reactive astrocytes. The factors that control the differentiation of NG2 cells after focal cerebral ischemia (FCI) are largely unknown. Here, we used transgenic Cspg4-cre/Esr1/ROSA26Sortm14(CAG-tdTomato) mice, in which tamoxifen administration triggers the expression of red fluorescent protein (tomato) specifically in NG2 cells and cells derived therefrom. Differentiation potential (in vitro and in vivo) of tomato-positive NG2 cells from control or postischemic brains was determined using the immunohistochemistry, single cell RT-qPCR and patch-clamp method. The ischemic injury was induced by middle cerebral artery occlusion, a model of FCI. Using genetic fate-mapping method, we identified sonic hedgehog (Shh) as an important factor that influences differentiation of NG2 cells into astrocytes in vitro. We also manipulated Shh signaling in the adult mouse brain after FCI. Shh signaling activation significantly increased the number of astrocytes derived from NG2 cells in the glial scar around the ischemic lesion, while Shh signaling inhibition caused the opposite effect. Since Shh signaling modifications did not change the proliferation rate of NG2 cells, we can conclude that Shh has a direct influence on the differentiation of NG2 cells and therefore, on the formation and composition of a glial scar, which consequently affects the degree of the brain damage. GLIA 2016;64:1518-1531.
- MeSH
- astrocyty metabolismus MeSH
- buněčná diferenciace fyziologie MeSH
- ischemie mozku patologie MeSH
- mozek cytologie MeSH
- myši MeSH
- neuroglie metabolismus MeSH
- oligodendroglie metabolismus MeSH
- počet buněk MeSH
- poranění mozku patologie MeSH
- proteiny hedgehog metabolismus MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Alzheimer's disease (AD) is a complex neurodegenerative disorder with major clinical hallmarks of memory loss, dementia, and cognitive impairment. Besides the extensive neuron-oriented research, an increasing body of evidence suggests that glial cells, namely astrocytes, microglia, NG2 glia and oligodendrocytes, may play an important role in the pathogenesis of this disease. In the first part of this review, AD pathophysiology in humans is briefly described and compared with disease progression in routinely used animal models. The relevance of findings obtained in animal models of AD is also discussed with respect to AD pathology in humans. Further, this review summarizes recent findings regarding the role/participation of glial cells in pathogenesis of AD, focusing on changes in their morphology, functions, proteins and gene expression profiles. As for astrocytes and microglia, they are fundamental for the progression and outcome of AD either because they function as effector cells releasing cytokines that play a role in neuroprotection, or because they fail to fulfill their homeostatic functions, ultimately leaving neurons to face excitotoxicity and oxidative stress. Next, we turn our attention towards NG2 glia, a novel and distinct class of glial cells in the central nervous system (CNS), whose role in a variety of human CNS diseases has begun to emerge, and we also consider the participation of oligodendrocytes in the pathogenesis and progression of AD. Since AD is currently an incurable disease, in the last part of our review we hypothesize about possible glia-oriented treatments and provide a perspective of possible future advancements in this field.
- MeSH
- Alzheimerova nemoc farmakoterapie patologie patofyziologie MeSH
- lidé MeSH
- neuroglie účinky léků patologie fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
1. vydání 294 stran : ilustrace ; 21 cm
- MeSH
- ochrana veřejného zdraví MeSH
- public relations MeSH
- reklama zaměřená na spotřebitele MeSH
- sociální marketing MeSH
- Geografické názvy
- Česká republika MeSH
- Konspekt
- Reklama. Public relations. Média
- NLK Obory
- sociologie
- NLK Publikační typ
- kolektivní monografie
Astrocytes respond to ischemic brain injury by proliferation, the increased expression of intermediate filaments and hypertrophy, which results in glial scar formation. In addition, they alter the expression of ion channels, receptors and transporters that maintain ionic/neurotransmitter homeostasis. Here, we aimed to demonstrate the expression of Hcn1-4 genes encoding hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in reactive astrocytes following focal cerebral ischemia (FCI) or global cerebral ischemia (GCI) and to characterize their functional properties. A permanent occlusion of the middle cerebral artery (MCAo) was employed to induce FCI in adult GFAP/EGFP mice, while GCI was induced by transient bilateral common carotid artery occlusion combined with hypoxia in adult rats. Using FACS, we isolated astrocytes from non-injured or ischemic brains and performed gene expression profiling using single-cell RT-qPCR. We showed that 2 weeks after ischemia reactive astrocytes express high levels of Hcn1-4 transcripts, while immunohistochemical analyses confirmed the presence of HCN1-3 channels in reactive astrocytes 5 weeks after ischemia. Electrophysiological recordings revealed that post-ischemic astrocytes are significantly depolarized, and compared with astrocytes from non-injured brains, they display large hyperpolarization-activated inward currents, the density of which increased 2-3-fold in response to ischemia. Their activation was facilitated by cAMP and their amplitudes were decreased by ZD7288 or low extracellular Na(+) concentration, suggesting that they may belong to the family of HCN channels. Collectively, our results demonstrate that regardless of the type of ischemic injury, reactive astrocytes express HCN channels, which could therefore be an important therapeutic target in poststroke therapy.
- MeSH
- AMP cyklický farmakologie MeSH
- astrocyty účinky léků metabolismus MeSH
- gliový fibrilární kyselý protein genetika metabolismus MeSH
- ischemie patologie MeSH
- kationtové kanály řízené cyklickými nukleotidy genetika metabolismus MeSH
- krysa rodu rattus MeSH
- membránové potenciály účinky léků fyziologie MeSH
- modely nemocí na zvířatech MeSH
- mozek cytologie MeSH
- myši transgenní MeSH
- myši MeSH
- neurony účinky léků metabolismus MeSH
- potkani Wistar MeSH
- proteiny nervové tkáně genetika metabolismus MeSH
- pyrimidiny farmakologie MeSH
- regulace genové exprese účinky léků fyziologie MeSH
- sodík metabolismus MeSH
- techniky in vitro MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mamografie je diagnostická metoda první volby při podezření na zhoubné onemocnění prsu. Pomáhá detekovat mikrokalcifikace, tj. malé shluky vápníku, které mohou být prvním signálem počínajícího zhoubného onemocnění. Vyšetření žen s prsními implantáty má však svá specifika.
Mammography is the first choice diagnostic method when malignant breast disease is suspected. It helps to detect microcalcifications which are small clusters of calcium that can be the first signs of malignant growth. Examination of women with breast implants has its own specifics.
- Klíčová slova
- augmentace, screening,
- MeSH
- implantace prsní náhrady MeSH
- lidé MeSH
- mamografie metody využití MeSH
- nádory prsu prevence a kontrola radiografie MeSH
- plošný screening MeSH
- projekce MeSH
- prsní implantáty MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
