Role of mitochondrial raft-like microdomains in the regulation of cell apoptosis

Lipid rafts are envisaged as lateral assemblies of specific lipids and proteins that dissociate and associate rapidly and form functional clusters in cell membranes. These structural platforms are not confined to the plasma membrane; indeed lipid microdomains are similarly formed at subcellular organelles, which include endoplasmic reticulum, Golgi and mitochondria, named raft-like microdomains. In addition, some components of raft-like microdomains are present within ER-mitochondria associated membranes. This review is focused on the role of mitochondrial raft-like microdomains in the regulation of cell apoptosis, since these microdomains may represent preferential sites where key reactions take place, regulating mitochondria hyperpolarization, fission-associated changes, megapore formation and release of apoptogenic factors. These structural platforms appear to modulate cytoplasmic pathways switching cell fate towards cell survival or death. Main insights on this issue derive from some pathological conditions in which alterations of microdomains structure or function can lead to severe alterations of cell activity and life span. In the light of the role played by raft-like microdomains to integrate apoptotic signals and in regulating mitochondrial dynamics, it is conceivable that these membrane structures may play a role in the mitochondrial alterations observed in some of the most common human neurodegenerative diseases, such as Amyotrophic lateral sclerosis, Huntington's chorea and prion-related diseases. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents in these pathologies

Silibinin induces mitochondrial NOX4-mediated endoplasmic reticulum stress response and its subsequent apoptosis

Background: Silibinin, a biologically active compound of milk thistle, has chemopreventive effects on cancer cell lines. Recently it was reported that silibinin inhibited tumor growth through activation of the apoptotic signaling pathway. Although various evidences showed multiple signaling pathways of silibinin in apoptosis, there were no reports to address the clear mechanism of ROS-mediated pathway in prostate cancer PC-3 cells. Several studies suggested that reactive oxygen species (ROS) play an important role in various signaling cascades, but the primary source of ROS was currently unclear. Methods: The effect of silibinin was investigated on cell growth of prostate cell lines by MTT assay. We examined whether silibinin induced apoptosis through production of ROS using flow cytometry. Expression of apoptosis-, endoplasmic reticulum (ER)-related protein and gene were determined by western blotting and RT-PCR, respectively. Results: Results showed that silibinin triggered mitochondrial ROS production through NOX4 expression and finally led to induce apoptosis. In addition, mitochondrial ROS caused ER stress through disruption of Ca2+ homeostasis. Co-treatment of ROS inhibitor reduced the silibinin-induced apoptosis through the inhibition of NOX4 expression, resulting in reduction of both Ca2+ level and ER stress response. Conclusions: Taken together, silibinin induced mitochondrial ROS-dependent apoptosis through NOX4, which is associated with disruption of Ca2+ homeostasis and ER stress response. Therefore, the regulation of NOX4, mitochondrial ROS producer, could be a potential target for the treatment of prostate cancer.ope

CHOP Mediates Endoplasmic Reticulum Stress-Induced Apoptosis in Gimap5-Deficient T Cells

Gimap5 (GTPase of the immunity-associated protein 5) has been linked to the regulation of T cell survival, and polymorphisms in the human GIMAP5 gene associate with autoimmune disorders. The BioBreeding diabetes-prone (BBDP) rat has a mutation in the Gimap5 gene that leads to spontaneous apoptosis of peripheral T cells by an unknown mechanism. Because Gimap5 localizes to the endoplasmic reticulum (ER), we hypothesized that absence of functional Gimap5 protein initiates T cell death through disruptions in ER homeostasis. We observed increases in ER stress-associated chaperones in T cells but not thymocytes or B cells from Gimap5−/− BBDP rats. We then discovered that ER stress-induced apoptotic signaling through C/EBP-homologous protein (CHOP) occurs in Gimap5−/− T cells. Knockdown of CHOP by siRNA protected Gimap5−/− T cells from ER stress-induced apoptosis, thereby identifying a role for this cellular pathway in the T cell lymphopenia of the BBDP rat. These findings indicate a direct relationship between Gimap5 and the maintenance of ER homeostasis in the survival of T cells

Neuropeptides, Trophic Factors, and Other Substances Providing Morphofunctional and Metabolic Protection in Experimental Models of Diabetic Retinopathy

Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these

Les communautés d'Actinobacteries dans les environnementaux naturels et anthropisés

Les actinobactéries sont un groupe bactérien important participant dans plusieurs processus écosystémiques comme la décomposition de composés organiques. Les actinobactéries possèdent des nombreuses capacités leur permettant de survivre dans des conditions difficiles comme celles retrouvées dans des habitats oligotrophes tels que les lacs, déserts, parois des grottes ou la litière végétale récalcitrante du sol où les actinobactéries dominent. Bien que certains facteurs biotiques et abiotiques ont été reconnus comme modulateurs de l'incidence des actinobactéries dans ces écosystèmes, l'influence des conditions changeantes provoquées par la pression anthropique sur leurs communautés reste inconnue. L´objectif principal de cette thèse est donc de déterminer des différences dans les communautés d’actinobactéries sous l’influence anthropique directe (visiteurs humains modifiant le microenvironnement des grottes, partie 1) et indirecte (facteurs liées à des changements climatiques : précipitations ou qualité de la litière végétale, partie 2) dans deux habitats : litière végétale du sol et parois des grottes, où les actinobactéries jouent un rôle important et prédominent. Dans une première partie de la thèse, nous avons suivi les communautés d´actinobactéries dans des parois de grottes calcaires françaises affectées différemment par l´homme (grottes vierges ou anthropisées). Pour la détection d´espèces potentiellement pathogènes ou productrices de pigments à partir d´ADN environnemental (Illumina MiSeq), nous avons utilisé le marqueur moléculaire hsp65 spécifique pour le genre Actinobacteria. Une attention particulière a été portée á la grotte de Lascaux, abritant des peintures paléolithiques et étant une des plus affectées d’un point de vue anthropique. Une comparaison au niveau de plusieurs salles affectées de façon différente par l’intervention humaine ainsi qu´entre zones des mêmes salles avec des marques visuelles d´origine microbienne sur les peintures murales a été faite dans cette grotte (article I). Dans la deuxième partie, nous avons surveillé les communautés d’actinobactéries de la litière végétale au cours d´un processus de décomposition sous conditions modifiées prévues (précipitation modifiée (article IV), différents types, qualités et origines de litière, (articles II, III, IV) dans différentes forêts (chêne méditerranéen et pin (article IV)), épicéa de montagne et hêtre (article III), forêt tempérée de hêtre (article II) et prairie (article II)). Nos résultats montrent que les communautés d’actinobactéries étaient fortement dépendantes du statut anthropisé/vierge des grottes (partie 1) ainsi que des changements climatiques et de qualité des litières pendant la décomposition (partie 2). Dans les grottes (partie 1), la structure des communautés d’actinobactéries a indiqué des perturbations anthropiques, où des taxons typiques d’environnements vierges ou anthropiques comprenant des espèces potentiellement pathogènes (identifiées selon le marqueur hsp65) ont été trouvés ayant un rapport avec l’anthropisation (article I). Lors de la décomposition (partie 2), nous avons constaté que les actinobactéries i) étaient affectées par le type de litière quel que soit son origine, mais leur dominance sur de la litière récalcitrante n´a pas entraîné une décomposition plus rapide (articles II, III, IV), ii) n´étaient pas directement affectés par les conditions climatiques (article III, IV) mais plutôt spécifiques au site (articles II, III, IV) avec du potentiel pour dominer dans des forêts de conifères introduites (articles III, IV), et iii) étaient influencées par des conditions différentes à celles des champignons (articles II, III, IV). Dans l´ensemble, les actinobactéries répondent principalement aux changements anthropiques au niveau de communautés ou d’espèces et sont capables de s 'adapter á ces changements conduisant á leur persistance dans les écosystèmes.Actinobacteria are important bacterial group participating in various ecosystem processes particularly in the decomposition of complex organic compounds. Their abilities enable them to surviving in harsh conditions of oligotrophic habitats like lakes, deserts, cave walls or recalcitrant and resistant litter in soil, where Actinobacteria often dominate. Although certain biotic and abiotic factors were recognized to modulate Actinobacteria incidence in such habitats, the influence of anthropogenic pressure on their communities is scarcely known. The main objective of this thesis is therefore to determine differences of Actinobacteria communities under the direct (the human visitors changing microenvironment of caves, part 1) and indirect (climate change factors like altered precipitation or plant litter quality, part 2) anthropogenic influence in two habitats, plant litter in soil and cave walls, where Actinobacteria play important roles and dominate. In a first part of the thesis we monitored Actinobacteria communities in French limestone caves walls differently affected by humans (pristine versus anthropized caves). For identification of important species like potential pathogens or pigments producing Actinobacteria using amplicon sequencing of environmental DNA (Illumina MiSeq), we firstly used a molecular marker gene hsp65 coding for heat shock protein specific for Actinobacteria. Special attention was payed to anthropogenically most affected Lascaux Cave with Paleolithic paintings. There, a comparison of different rooms differently affected by a human-derived intervention as well as between visual dark marks and unmarked areas on the wall paintings were compared (paper I). In the second part, we monitored litter Actinobacteria communities during a decomposition process under manipulated precipitation (paper IV), on different litter type, quality and origin (papers II, III, IV) in different forests including Mediterranean oak and pine forests (paper IV), mountainous spruce and beech forests (paper III), a beech temperate forest (paper II)) and also one grassland (paper II). Our results show that Actinobacteria communities were strongly dependent to anthropized/pristine status of caves (Part 1) as well as climatic and litter quality changes during the decomposition (Part 2). In caves (Part 1), Actinobacteria community structure indicated the anthropogenic disturbance, because typical pristine and anthropogenic taxa identified according to the hsp65 marker were recovered in relation to an anthropization status (paper I). During decomposition (part 2), we found that Actinobacteria were i) affected by litter type regardless its origin but their dominance on recalcitrant litter type did not result in faster decomposition (papers II, III, IV), ii) not directly affected by climatic conditions (paper III, IV) but were site-specific (papers II, III, IV) with a potential to dominate introduced coniferous forests (papers III, IV), and iii) in decomposition process had opposite strategies to fungi, since were influenced by different conditions than fungi (papers II, III, IV). Overall, Actinobacteria respond to anthropogenic pressure on a community and species level and are also able to adapt to harsh conditions and thus, these changes leading to Actinobacteria persistence in ecosystems

Les communautés d'Actinobacteries dans les environnementaux naturels et anthropisés

Actinobacteria are important bacterial group participating in various ecosystem processes particularly in the decomposition of complex organic compounds. Their abilities enable them to surviving in harsh conditions of oligotrophic habitats like lakes, deserts, cave walls or recalcitrant and resistant litter in soil, where Actinobacteria often dominate. Although certain biotic and abiotic factors were recognized to modulate Actinobacteria incidence in such habitats, the influence of anthropogenic pressure on their communities is scarcely known. The main objective of this thesis is therefore to determine differences of Actinobacteria communities under the direct (the human visitors changing microenvironment of caves, part 1) and indirect (climate change factors like altered precipitation or plant litter quality, part 2) anthropogenic influence in two habitats, plant litter in soil and cave walls, where Actinobacteria play important roles and dominate. In a first part of the thesis we monitored Actinobacteria communities in French limestone caves walls differently affected by humans (pristine versus anthropized caves). For identification of important species like potential pathogens or pigments producing Actinobacteria using amplicon sequencing of environmental DNA (Illumina MiSeq), we firstly used a molecular marker gene hsp65 coding for heat shock protein specific for Actinobacteria. Special attention was payed to anthropogenically most affected Lascaux Cave with Paleolithic paintings. There, a comparison of different rooms differently affected by a human-derived intervention as well as between visual dark marks and unmarked areas on the wall paintings were compared (paper I). In the second part, we monitored litter Actinobacteria communities during a decomposition process under manipulated precipitation (paper IV), on different litter type, quality and origin (papers II, III, IV) in different forests including Mediterranean oak and pine forests (paper IV), mountainous spruce and beech forests (paper III), a beech temperate forest (paper II)) and also one grassland (paper II). Our results show that Actinobacteria communities were strongly dependent to anthropized/pristine status of caves (Part 1) as well as climatic and litter quality changes during the decomposition (Part 2). In caves (Part 1), Actinobacteria community structure indicated the anthropogenic disturbance, because typical pristine and anthropogenic taxa identified according to the hsp65 marker were recovered in relation to an anthropization status (paper I). During decomposition (part 2), we found that Actinobacteria were i) affected by litter type regardless its origin but their dominance on recalcitrant litter type did not result in faster decomposition (papers II, III, IV), ii) not directly affected by climatic conditions (paper III, IV) but were site-specific (papers II, III, IV) with a potential to dominate introduced coniferous forests (papers III, IV), and iii) in decomposition process had opposite strategies to fungi, since were influenced by different conditions than fungi (papers II, III, IV). Overall, Actinobacteria respond to anthropogenic pressure on a community and species level and are also able to adapt to harsh conditions and thus, these changes leading to Actinobacteria persistence in ecosystems.Les actinobactéries sont un groupe bactérien important participant dans plusieurs processus écosystémiques comme la décomposition de composés organiques. Les actinobactéries possèdent des nombreuses capacités leur permettant de survivre dans des conditions difficiles comme celles retrouvées dans des habitats oligotrophes tels que les lacs, déserts, parois des grottes ou la litière végétale récalcitrante du sol où les actinobactéries dominent. Bien que certains facteurs biotiques et abiotiques ont été reconnus comme modulateurs de l'incidence des actinobactéries dans ces écosystèmes, l'influence des conditions changeantes provoquées par la pression anthropique sur leurs communautés reste inconnue. L´objectif principal de cette thèse est donc de déterminer des différences dans les communautés d’actinobactéries sous l’influence anthropique directe (visiteurs humains modifiant le microenvironnement des grottes, partie 1) et indirecte (facteurs liées à des changements climatiques : précipitations ou qualité de la litière végétale, partie 2) dans deux habitats : litière végétale du sol et parois des grottes, où les actinobactéries jouent un rôle important et prédominent. Dans une première partie de la thèse, nous avons suivi les communautés d´actinobactéries dans des parois de grottes calcaires françaises affectées différemment par l´homme (grottes vierges ou anthropisées). Pour la détection d´espèces potentiellement pathogènes ou productrices de pigments à partir d´ADN environnemental (Illumina MiSeq), nous avons utilisé le marqueur moléculaire hsp65 spécifique pour le genre Actinobacteria. Une attention particulière a été portée á la grotte de Lascaux, abritant des peintures paléolithiques et étant une des plus affectées d’un point de vue anthropique. Une comparaison au niveau de plusieurs salles affectées de façon différente par l’intervention humaine ainsi qu´entre zones des mêmes salles avec des marques visuelles d´origine microbienne sur les peintures murales a été faite dans cette grotte (article I). Dans la deuxième partie, nous avons surveillé les communautés d’actinobactéries de la litière végétale au cours d´un processus de décomposition sous conditions modifiées prévues (précipitation modifiée (article IV), différents types, qualités et origines de litière, (articles II, III, IV) dans différentes forêts (chêne méditerranéen et pin (article IV)), épicéa de montagne et hêtre (article III), forêt tempérée de hêtre (article II) et prairie (article II)). Nos résultats montrent que les communautés d’actinobactéries étaient fortement dépendantes du statut anthropisé/vierge des grottes (partie 1) ainsi que des changements climatiques et de qualité des litières pendant la décomposition (partie 2). Dans les grottes (partie 1), la structure des communautés d’actinobactéries a indiqué des perturbations anthropiques, où des taxons typiques d’environnements vierges ou anthropiques comprenant des espèces potentiellement pathogènes (identifiées selon le marqueur hsp65) ont été trouvés ayant un rapport avec l’anthropisation (article I). Lors de la décomposition (partie 2), nous avons constaté que les actinobactéries i) étaient affectées par le type de litière quel que soit son origine, mais leur dominance sur de la litière récalcitrante n´a pas entraîné une décomposition plus rapide (articles II, III, IV), ii) n´étaient pas directement affectés par les conditions climatiques (article III, IV) mais plutôt spécifiques au site (articles II, III, IV) avec du potentiel pour dominer dans des forêts de conifères introduites (articles III, IV), et iii) étaient influencées par des conditions différentes à celles des champignons (articles II, III, IV). Dans l´ensemble, les actinobactéries répondent principalement aux changements anthropiques au niveau de communautés ou d’espèces et sont capables de s 'adapter á ces changements conduisant á leur persistance dans les écosystèmes

Highly Textured Seed Layers for the Growth of Vertically Oriented ZnO Nanorods

One dimensional ZnO nanostructures prepared by favorable and simple solution growth methods are at the forefront of this research. Vertically oriented ZnO nanorods with uniform physical properties require high-quality seed layers with a narrow size distribution of the crystallites, strong c-axis orientation, and low surface roughness and porosity. It has been shown that high quality seed layers can be prepared by the sol–gel process. The sol–gel process involves three essential steps: preparation of the sol, its deposition by dip coating, and thermal treatment comprising preheating and annealing. We put emphasis on the investigation of the heat treatment on the properties of the seed layers and on the vertical alignment of the nanorods. It was demonstrated that for the vertical alignment of the nanorods, the preheating step is crucial and that the temperatures reported in the literature have been too low. With higher preheating temperatures, conditions for the vertical alignment of the nanorods were achieved in both investigated annealing atmospheres in air and in argon

Comparison of Actinobacteria communities from human‐impacted and pristine karst caves

International audienceActinobacteria are important cave inhabitants, but knowledge of how anthropization and anthropization-related visual marks affect this community on cave walls is lacking. We compared Actinobacteria communities among four French limestone caves (Mouflon, Reille, Rouffignac, and Lascaux) ranging from pristine to anthropized, and within Lascaux Cave between marked (wall visual marks) and unmarked areas in different rooms (Sas-1, Passage, Apse, and Diaclase). In addition to the 16S rRNA gene marker, 441 bp fragments of the hsp65 gene were used and an hsp65-related taxonomic database was constructed for the identification of Actinobacteria to the species level by Illumina-MiSeq analysis. The hsp65 marker revealed higher resolution for species and higher richness (99% operational taxonomic units cutoff) versus the 16S rRNA gene; however, more taxa were identified at higher taxonomic ranks. Actinobacteria communities varied between Mouflon and Reille caves (both pristine), and Rouffignac and Lascaux (both anthropized). Rouffignac displayed high diversity of Nocardia, suggesting human inputs, and Lascaux exhibited high Mycobacterium relative abundance, whereas Gaiellales were typical in pristine caves and the Diaclase (least affected area of Lascaux Cave). Within Lascaux, Pseudonocardiaceae dominated on unmarked walls and Streptomycetaceae (especially Streptomyces mirabilis) on marked walls, indicating a possible role in mark formation. A new taxonomic database was developed. Although not all Actinobacteria species were represented, the use of the hsp65 marker enabled species-level variations of the Actinobacteria community to be documented based on the extent of anthropogenic pressure. This approach proved effective when comparing different limestone caves or specific conditions within one cave