1,720,972 research outputs found
Identificazione di nuovi target terapeutici per il trattamento delle neurodegenerazioni sensoriali dell'orecchio
No full textHearing loss represents the fourth cause of disability in the world according to the Global Burden of Disease Study, and the number of affected patients is expected to increase in the next years. The absence of effective therapies for the treatment of sensorineural hearing loss leads to irreversible deafness and calls for an urgent need of new therapeutic approaches. To make improvements in the field, in this dissertation, we investigated the effects of recombinant human nerve growth factor (rhNGF) and recombinant human brain derived neurotrophic factor (rhBDNF) on sensory and non-sensory cells of the organ of Corti. To this purpose, the experiments have been conducted by three partners in the framework of the “PON ricerca e innovazione”: the University of L’Aquila (L’Aquila, Italy), Dompé Farmaceutici S.p.A (Naples, Italy), and University Medical Center (UMC) Utrecht (Utrecht, The Netherlands).
The first objective of the project was the investigation of the miRNAs profiles induced by rhNGF and rhBDNF in vitro on murine cochlear cells derived from the organ of Corti. The subsequent in silico analysis allowed us to identify a wide spectrum of target genes and signalings by the modulated miRNAs. Importantly, many of the target pathways by both neurotrophins involved cell survival, proliferation, neuronal differentiation and metabolic pathways.
As a second step, we investigated the effects of rhNGF and rhBDNF on the survival of sensory and non-sensory cells of the organ of Corti of ototoxically deafened guinea pigs, and found limited effects in terms of cell number by both the treatments. At this level, we did not take into account any other aspects, such as the molecular events underlying the activity of those cells, that could affect their function.
We therefore moved to molecular investigations in the organ of Corti of deafened guinea pigs. We selected the mTOR signaling from the in vitro and in silico analysis. Since the mTOR signaling was predominantly modulated by rhBDNF, we limited our investigations to this neurotrophin. We found that the BDNF-treated organs of Corti from deafened guinea pigs presented increased levels of pmTOR compared to normal hearing ears, and increased levels of mTOR compared to both untreated and normal hearing cochleas. On this basis, it is possible that rhBDNF may exert a protective effect on the organ of Corti that is mainly associated with the molecular function of those cells and not appreciable in terms of cell number.
In conclusion, this dissertation provides a comprehensive overview over the effects of rhNGF and rhBDNF in the organ of Corti, and lays the foundation for the identification of new therapeutic targets
Towards the identification of L-DOPA mechanisms of action on retinal pigment epithelial cells: insights for Age Related Macular Degeneration
No full text
Advanced Omics Techniques for Understanding Cochlear Genome, Epigenome, and Transcriptome in Health and Disease
No full textAdvanced genomics, transcriptomics, and epigenomics techniques are providing unprecedented insights into the understanding of the molecular underpinnings of the central nervous system, including the neuro-sensory cochlea of the inner ear. Here, we report for the first time a comprehensive and updated overview of the most advanced omics techniques for the study of nucleic acids and their applications in cochlear research. We describe the available in vitro and in vivo models for hearing research and the principles of genomics, transcriptomics, and epigenomics, alongside their most advanced technologies (like single-cell omics and spatial omics), which allow for the investigation of the molecular events that occur at a single-cell resolution while retaining the spatial information
Nanoceria protect retinal pigment epithelium in the light damaged retina
No full textPurpose : Dry age-related macular degeneration (AMD) is the most common form of AMD, characterized by retinal pigment epithelium (RPE) dysfunction and death, associated to lipofuscin accumulation, photoreceptors death, autophagy alterations and vision loss. Despite its frequency, only palliative therapies are available. In order to search for improvements we investigated the development of the dry AMD in the light damaged (LD) model and tested the protective effects of cerium oxide nanoparticles (nanoceria).
Methods : The dry features of AMD were investigated on Sprague Dawley albino rats exposed to bright light (1000 lux) for 3h, 6h, 9h, 12h, 24h and for 24h followed by 3 and 7 days of recovery, then compared to the healthy controls. The treatment was performed by nanoceria intravitreal injection (2 μl [1mM]) in both eyes 3 days before light exposure (for 24h). After 7 days from injury treated and untreated animals were compared. Oxidative stress was evaluated by acrolein fluorescence intensity on immunolabeled retinal cryosections and RPE was pointed out by anti-RPE65 immunofluorescence. Lipofuscin quantitation was performed by ImageJ software on retinal whole mounts images acquired by confocal microscopy. Autophagy was analysed by LC3B-II western blot.
Results : The RPE was disrupted in the dorsal retina of LD rats starting 3 days after injury. LCB3-II was significantly increased after 24h of light exposure (p<0,05) and remained up-regulated after 7 days of recovery (p<0,05). We also observed lipofuscin accumulation over time and increased oxidative stress already detectable after 7 days of recovery. By nanoceria treatment oxidative stress was significantly reduced in the outer nuclear layer (p<0,01) and in the RPE (p<0,05) of the treated group. Accordingly the blood-retinal barrier was intact since the RPE was not affected and lipofuscin was significantly reduced in terms of number of granules (p<0,001) and percentage of occupied area (p<0,001). LCB3-II was down-regulated in the nanoceria-treated animals compared to the untreated ones (p<0,001).
Conclusions : Our study demonstrates that cerium oxide nanoparticles protect the RPE and limit the dry features of AMD in the light-damaged model. On this basis we propose nanoceria as a new potential therapeutic agent for the dry form of AMD
An overview of retinal light damage models for preclinical studies on age-related macular degeneration: identifying molecular hallmarks and therapeutic targets
Full text linkAge-related macular degeneration (AMD) is a complex, multifactorial disease leading to progressive and irreversible retinal degeneration, whose pathogenesis has not been fully elucidated yet. Due to the complexity and to the multiple features of the disease, many efforts have been made to develop animal models which faithfully reproduce the overall AMD hallmarks or that are able to mimic the different AMD stages. In this context, light damage (LD) rodent models of AMD represent a suitable and reliable approach to mimic the different AMD forms (dry, wet and geographic atrophy) while maintaining the time-dependent progression of the disease. In this review, we comprehensively reported how the LD paradigms reproduce the main features of human AMD. We discuss the capability of these models to broaden the knowledge in AMD research, with a focus on the mechanisms and the molecular hallmarks underlying the pathogenesis of the disease. We also critically revise the remaining challenges and future directions for the use of LD models
mTOR Signaling in BDNF-Treated Guinea Pigs after Ototoxic Deafening
Full text linkThe mammalian target of rapamycin (mTOR) signaling plays a critical role in cell homeostasis, growth and survival. Here, we investigated the localization of the main mTOR signaling proteins in the organ of Corti of normal-hearing and deafened guinea pigs, as well as their possible modulation by exogenously administered brain-derived neurotrophic factor (BDNF) in deafened guinea pigs. Animals were ototoxically deafened by systemic administration of kanamycin and furosemide, and one week later, the right cochleas were treated with gelatin sponge soaked in rhBDNF, while the left cochleas were used as negative controls. Twenty-four hours after treatment, animals were euthanized, and the cochleas were processed for subsequent analysis. Through immunofluorescence, we demonstrated the localization of AKT, pAKT, mTOR, pmTOR and PTEN proteins throughout the cochlea of guinea pigs for the first time, with a higher expression in supporting cells. Moreover, an increase in mTOR immunostaining was observed in BDNF-treated cochleas by means of fluorescence intensity compared to the other groups. Conversely, Western blot analysis showed no significant differences in the protein levels between groups, probably due to dilution of proteins in the neighboring tissues of the organ of Corti. Altogether, our data indicate that mTOR signaling proteins are expressed by the organ of Corti (with a major role for supporting cells) and that the modulation of mTOR may be a protective mechanism triggered by BDNF in the degenerating organ of Corti
Nanoceria Particles Are an Eligible Candidate to Prevent Age-Related Macular Degeneration by Inhibiting Retinal Pigment Epithelium Cell Death and Autophagy Alterations
Full text linkRetinal pigment epithelium (RPE) dysfunction and degeneration underlie the development of age-related macular degeneration (AMD), which is the leading cause of blindness worldwide. In this study, we investigated whether cerium oxide nanoparticles (CeO2-NPs or nanoceria), which are anti-oxidant agents with auto-regenerative properties, are able to preserve the RPE. On ARPE-19 cells, we found that CeO2-NPs promoted cell viability against H2O2–induced cellular damage. For the in vivo studies, we used a rat model of acute light damage (LD), which mimics many features of AMD. CeO2-NPs intravitreally injected three days before LD prevented RPE cell death and degeneration and nanoceria labelled with fluorescein were found localized in the cytoplasm of RPE cells. CeO2-NPs inhibited epithelial-mesenchymal transition of RPE cells and modulated autophagy by the down-regulation of LC3B-II and p62. Moreover, the treatment inhibited nuclear localization of LC3B. Taken together, our study demonstrates that CeO2-NPs represent an eligible candidate to counteract RPE degeneration and, therefore, a powerful therapy for AMD
- …
