47 research outputs found
CaractĂ©risation de lâubiquitin-fold modifier (UFM1) dans un modĂšle C. elegans
Lâubiquitin-fold modifier (UFM1) fait partie de la classe 1 de la famille de protĂ©ine ubiquitin-like (Ubl). UFM1 et Ub ont trĂšs peu dâhomologie de sĂ©quence, mais partagent des similaritĂ©s remarquables au niveau de leur structure tertiaire. Tout comme lâUb et la majoritĂ© des autres Ubls, UFM1 se lie de façon covalente Ă ses substrats par lâintermĂ©diaire dâune cascade enzymatique. Il est de plus en plus frĂ©quemment rapportĂ© que les protĂ©ines Ubls sont impliquĂ©es dans des maladies humaines. Le gĂšne Ufm1 est surexprimĂ© chez des souris de type MCP dĂ©veloppant une ischĂ©mie myocardique et dans les Ăźlots de Langerhans de patients atteints du diabĂšte de type 2. UFM1 et ses enzymes spĂ©cifiques, UBA5, UFL1 et UFC1, sont conservĂ©s chez les mĂ©tazoaires et les plantes suggĂ©rant un rĂŽle important pour les organismes multicellulaires.
Le Caenorhabditis elegans est le modĂšle animal le plus simple utilisĂ© en biologie. Sa morphologie, ses phĂ©notypes visibles et ses lignĂ©es cellulaires ont Ă©tĂ© dĂ©crits de façon dĂ©taillĂ©e. De plus, son cycle de vie court permet de rapidement observer les effets de certains gĂšnes sur la longĂ©vitĂ©. Ce modĂšle nous permet de facilement manipuler lâexpression du gĂšne Ufm1 et de mieux connaĂźtre ses fonctions.
En diminuant lâexpression du gĂšne ufm-1 chez le C.elegans, par la technique de lâARN interfĂ©rence par alimentation, nous nâavons observĂ© aucun problĂšme morphologique grave. Les vers ressemblaient aux vers sauvages et possĂ©daient un nombre de progĂ©niture normal. Cependant, les vers sauvage exposĂ©s Ă lâARNi dâufm-1 vivent significativement moins longtemps que les contrĂŽles et ce, de façon indĂ©pendante de la voie de signalisation de lâinsuline/IGF. Chez le C. elegans la longĂ©vitĂ© et la rĂ©sistance au stress cellulaire sont intimement liĂ©es. Nous nâavons remarquĂ© aucun effet dâufm-1 sur le stress thermal, osmotique ou oxydatif, mais il est requis pour la protection contre le stress protĂ©otoxique. Il est Ă©galement nĂ©cessaire au maintien de lâintĂ©gritĂ© neuronale au cours du vieillissement des animaux. Lâensemble de nos donnĂ©es nous renseigne sur les fonctions putatives du gĂšne Ufm1.The ubiquitin-fold modifier (UFM1) is part of the type 1 class of the family of ubiquitin-like protein (Ubl). UFM1 and Ub have very little sequence homology but share remarkable similarities in their tertiary structure. Like Ub and most other UBLS, UFM1 binds covalently to its substrates through an enzymatic cascade. It is frequently reported that UBLs are involved in human diseases. UFM-1 is overexpressed in mice developing a myocardial ischemia and in the islets of patients suffering from type 2 diabetes. UFM1 and its specific enzymes, UBA5, UFL1, and UFC1 are conserved in metazoans and plants suggesting an important role in multicellular organisms.
Caenorhabditis elegans is one of the the simplest animal models used in biology. Some features such as morphology, visible phenotypes and cell lineage have completely been described. The short lifecycle of C. elegans makes it easy to observe gene effects on longevity. This model allows us to easily manipulate the expression of the Ufm1 gene and learn more about its putative functions.
To study putative functions of Ufm1, we decreased the expression of ufm-1 using RNA interference introduces through feeding. No gross morphological disturbances were observed; worms resembled wild type and had a normal brood size. However, worms exposed to ufm-1 RNAi had a significantly shorter lifespan than the controls. This effect is independent of the insulin/IGF pathway, which is a major axis of longevity genetics. In C. elegans longevity and cellular stress resistance are intimately linked. We have observed no effect of ufm-1 on thermal, osmotic or oxidative stress, but it is required for protection against proteotoxic stress. It is also necessary to maintain neuronal integrity during aging. Together, our results shed light on putative functions of Ufm1 gene
Cucurbitacin E has neuroprotective properties and autophagic modulating activities on dopaminergic neurons
Natural molecules are under intensive study for their potential as preventive and/or adjuvant therapies for neurodegenerative disorders such as Parkinsonâs disease (PD). We evaluated the neuroprotective potential of cucurbitacin E (CuE), a tetracyclic triterpenoid phytosterol extracted from the Ecballium elaterium (Cucurbitaceae), using a known cellular model of PD, NGF-differentiated PC12. In our postmitotic experimental paradigm, neuronal cells were treated with the parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP+) to provoke significant cellular damage and apoptosis or with the potent N,N-diethyldithiocarbamate (DDC) to induce superoxide () production, and CuE was administered prior to and during the neurotoxic treatment. We measured cellular death and reactive oxygen species to evaluate the antioxidant and antiapoptotic properties of CuE. In addition, we analyzed cellular macroautophagy, a bulk degradation process involving the lysosomal pathway. CuE showed neuroprotective effects on MPP+-induced cell death. However, CuE failed to rescue neuronal cells from oxidative stress induced by MPP+ or DDC. Microscopy and western blot data show an intriguing involvement of CuE in maintaining lysosomal distribution and decreasing autophagy flux. Altogether, these data indicate that CuE decreases neuronal death and autophagic flux in a postmitotic cellular model of PD.peer-reviewe
Rapamycin administration is not a valid therapeutic strategy for every case of mitochondrial disease
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.ebiom.2019.03.025.Background: The vastmajority ofmitochondrial disorders have limited the clinicalmanagement to palliative care.
Rapamycin has emerged as a potential therapeutic drug formitochondrial diseases since it has shown therapeutic
benefits in a fewmousemodels ofmitochondrial disorders. However, the underlying therapeutic mechanism
is unclear, theminimal effective dose needs to be defined and whether this therapy can be generally used is unknown.
Methods: Wehave evaluatedwhether lowand high doses of rapamycin administration may result in therapeutic
effects in a mousemodel (Coq9R239X) ofmitochondrial encephalopathy due to CoQ deficiency. The evaluation involved
phenotypic, molecular, image (histopathology and MRI),metabolomics, transcriptomics and bioenergetics
analyses.
Findings: Low dose of rapamycin induces metabolic changes in liver and transcriptomics modifications in midbrain.
The high dose of rapamycin induces further changes in the transcriptomics profile in midbrain due to
the general inhibition of mTORC1. However, neither low nor high dose of rapamycin were able to improve the
mitochondrial bioenergetics, the brain injuries and the phenotypic characteristics of Coq9R239X mice, resulting
in the lack of efficacy for increasing the survival.
Interpretation: These results may be due to the lack ofmicrogliosis-derived neuroinflammation, the limitation to
induce autophagy, or the need of a functional CoQ-junction. Therefore, the translation of rapamycin therapy into
the clinic for patients with mitochondrial disorders requires, at least, the consideration of the particularities of
each mitochondrial disease.Supported by the grants from âFundaciĂłn Isabel Gemio - FederaciĂłn Española de Enfermedades
Neuromusculares â FederaciĂłn FEDERâ (TSR-1), the NIH (P01HD080642) and the ERC (Stg-337327)
Mutations in the Mitochondrial Methionyl-tRNA Synthetase Cause a Neurodegenerative Phenotype in Flies and a Recessive Ataxia (ARSAL) in Humans
The study of Drosophila neurodegenerative mutants combined with genetic and biochemical analyses lead to the identification of multiple complex mutations in 60 patients with a novel form of ataxia/leukoencephalopathy
Alternative approach for stent grafting of the thoracic descending aorta: The antegrade right axillary approach
TCT-820 Transcatheter Aortic Valve Implantation (TAVI) In Patients Unsuitable For A Transfemoral Approach: A Comparison Between Trans-apical and Trans-Axillary Approaches
Preliminary Experience Using Diastolic Right Ventricular Pressure Gradient Monitoring in Cardiac Surgery
Del Nido cardioplegia in the setting of minimally invasive aortic valve surgery
The purpose of this study is to report our experience with del Nido cardioplegia (DNC) in the setting of minimally
invasive aortic valve surgery. Forty-six consecutive patients underwent minimally invasive aortic valve replacement (AVR)
through a âJâ ministernotomy: twenty-five patients received the DNC (Group 1) and 21 patients received standard
blood cardioplegia (SBC) (Group 2). The rate of ventricular fibrillation at unclamping was significantly lower in the DNC
group (12% vs 52%, p=0.004), as well as postoperative creatinine kinase-MB (CK-MB) values (11.4±5.2 vs 17.7±6.9 Όg/L,
p=0.004). There were no deaths, myocardial infarctions or major complications in either group. Less postoperative
use of intravenous insulin (28% vs 81%, p<0.001) was registered in the DNC group. In conclusion, the DNC is easy to
use and safe during minimally invasive AVR, providing a myocardial protection at least equivalent to our SBC, improved
surgical efficiency, minimal cost and less blood glucose perturbations