Mutation of the RB-1 tumour suppressor occurs in one third of all human tumours and is particularly associated with retinoblastoma and osteosarcoma1. Numerous functions have been ascribed to the product of the human RB-1 gene, pRB. The best known is pRB’s ability to promote cell cycle exit through inhibition of the E2F transcription factors and the transcriptional repression of genes encoding cell cycle regulators1. In addition, pRB has been shown in vitro to regulate several transcription factors that are master differentiation inducers2. Depending on the differentiation factor and cellular context, pRB can either suppress or promote their transcriptional activity. For example, pRB binds to Runx2 and potentiates its ability to promote osteogenic differentiation program in vitro3. In contrast, pRB acts together with E2F to suppress PPARγ, the master activator of adipogenesis4,5. Since osteoblasts and adipocytes can both arise from mesenchymal stem cells, these observations suggest that pRB might play a role in the choice between these two fates. However, to date, there is no evidence for this in vivo. Here we use mouse models to address this hypothesis in the context of mesenchymal tissue development and tumorigenesis. Our data show that Rb status plays a key role in establishing fate choice between bone and brown adipose tissue in vivo.

The retinoblastoma protein gene RB-1 is mutated in one-third of human tumors. Its protein product, pRB (retinoblastoma protein), functions as a transcriptional coregulator in many fundamental cellular processes. Here, we report a nonnuclear role for pRB in apoptosis induction via pRB's direct participation in mitochondrial apoptosis. We uncovered this activity by finding that pRB potentiated TNFa-induced apoptosis even when translation was blocked. This proapoptotic function was highly BAX-dependent, suggesting a role in mitochondrial apoptosis, and accordingly, a fraction of endogenous pRB constitutively associated with mitochondria. Remarkably, we found that recombinant pRB was sufficient to trigger the BAX-dependent permeabilization of mitochondria or liposomes in vitro. Moreover, pRB interacted with BAX in vivo and could directly bind and conformationally activate BAX in vitro. Finally, by targeting pRB specifically to mitochondria, we generated a mutant that lacked pRB's classic nuclear roles. This mito-tagged pRB retained the ability to promote apoptosis in response to TNFa and also additional apoptotic stimuli. Most importantly, induced expression of mito-tagged pRB in Rb -/-;p53 -/-tumors was sufficient to block further tumor development. Together, these data establish a nontranscriptional role for pRB in direct activation of BAX and mitochondrial apoptosis in response to diverse stimuli, which is profoundly tumor-suppressive.

Studies of long-lived Caenorhabditis elegans mutants have identified several genes that function to limit lifespan, i.e., loss-of-function mutations in these genes promote longevity. By contrast, little is known about genes that normally act to delay aging and that when mutated cause premature aging (progeria). To seek such genes, we performed a genetic screen for C. elegans mutants that age prematurely. We found that loss-of-function mutations of the ketoacyl thiolase gene kat-1 result in an increased accumulation of the lipofuscin-like fluorescent aging pigment, shortened lifespan, early behavioral decline, and other abnormalities characteristic of premature aging. These findings suggest that kat-1 acts to delay C. elegans aging. kat-1 encodes a conserved metabolic enzyme that catalyzes the last step of fatty acid oxidation and was previously shown to regulate fat accumulation in worms. We observed that kat-1 is required for the extension of lifespan and enhanced thermotolerance mediated by extra copies of the deacetylase gene sir-2.1. kat-1 acts independently of other known pathways that affect longevity. Our findings suggest that defects in fatty acid oxidation can limit lifespan and accelerate aging in C. elegans and that kat-1-mediated fatty acid oxidation is crucial for overexpressed sir-2.1 to delay aging.progeria | lipofuscin | fatty acid oxidation | sirtuins | protein deacetylation

Plangerea administrativ-jurisdictionala, ca instrument juridic specific dreptului executional penal, pus la indemana persoanelor private de libertate, nu a facut niciodata obiectul vreunei analize ”din interior”, sub aspectul intelegerii conceptului, al mecanismelor nationale si internationale de depunere a acestor plangeri, al scopului acestor plangeri, al modalitatilor de solutionare etc. Lucrarea de fata are caracter de noutate, acesta constand in faptul ca abordeaza un domeniu de nisa, al dreptului executional penal, fiind o examinare a posibilitatilor practice prin care persoanele private de libertate nemultumite de modul in care le sunt solutionate solicitarile, ori de faptul ca le-au fost incalcate drepturile, pot apela la acest instrument juridic pentru a le fi analizate solicitarile de catre un organ independent, si anume judecatorul de supraveghere a privarii de libertate. De asemenea, lucrarea abordeaza si ofera solutii, prin propuneri de lege ferenda, de eliminare a incongruentelor legislative constatate intre actele normative ce reglementeaza executarea pedepselor si masurilor privative de libertate, dar si de rezolvare a unor situatii pe care legiuitorul nu le-a reglementat prin Legea nr. 254/2013 pentru executarea pedepselor si masurilor privative de libertate, cum ar fi cel al abuzului de drept savarsit de persoanele private de libertate, prin formularea de plangeri repetitive, fara finalitate sau prin folosirea unui limbaj denigrator, ofensator, vexator, al stabilirii riscului si al gradelor de risc, al riscului de recidiva etc.

Activating germline K-ras mutations cause Noonan syndrome (NS), which is characterized by several developmental deficits including cardiac defects, cognitive delays and skeletal abnormalities. NS patients have increased signaling through the MAPK pathway. To model NS skeletal defects and understand the effect of hyperactive K-ras signaling on normal limb development, we generated a mouse model in which activated Kras G12D was expressed specifically in mesenchymal progenitors of the limb bud. These mice display short, abnormally mineralized long bones that phenocopy those of NS patients. This defect was first apparent at E14.5, and was characterized by a delay in bone collar formation. Coincident mutation of p53 had no effect on the K-ras G12D induced bone defect, arguing that it is does not result from senescence or apoptosis. Instead, our data revealed profound defects in the development of the committed osteoblasts; their appearance is delayed, concordant with the delay in bone collar formation, and they display an aberrant localization outside of the bone shaft. Additionally, we see growth plate defects including a reduction in the hypertrophic chondrocyte layer. Most importantly, we found that in utero delivery of a MEK inhibitor between E10.5 and E14.5 is sufficient to completely suppress