Metabolic regulation by p53 family members

The function of p53 is best understood in response to genotoxic stress, but increasing evidence suggests that p53 also plays a key role in the regulation of metabolic homeostasis. p53 and its family members directly influence various metabolic pathways, enabling cells to respond to metabolic stress. These functions are likely to be important for restraining the development of cancer but could also have a profound effect on the development of metabolic diseases, including diabetes. A better understanding of the metabolic functions of p53 family members may aid in the identification of therapeutic targets and reveal novel uses for p53-modulating drugs

Historische en hedendaagse systeem-innovaties in de glastuinbouw en varkenshouderij: Een innovatie-sociologische analyse

Transities en systeem-innovaties in de landbouw zijn het thema van dit rapport. Klimaatverandering, energiegebruik, methaan-emissies, dierenwelzijn, economische concurrentie, voedselschandalen (BSE, dioxine), verzuring, stankproblemen, landschapsinrichting, en rurale ontwikkeling zijn enkele van de socio-economische ontwikkelingen die druk creëren op het landbouwsysteem. Veel van deze ontwikkelingen kunnen (waarschijnlijk) niet binnen de grenzen van het bestaande systeem het hoofd geboden worden. Daarom is het thema van transities naar nieuwe systemen (systeem-innovatie) gestegen op de maatschappelijke en politieke agenda. Wat betreft empirische focus gaat dit rapport over transities in twee sectoren: glastuinbouw en varkenshouderij. Voor beide sectoren is een studie gedaan van historische transities en een studie van contemporaine transities ‘in the making’. Hedentendaage, staat de glastuinbouw onder druk wegens hoog energiegebruik (en dus CO2 emissies en klimaatverandering), vooral gerelateerd aan ruimteverwarming met gas. De varkenssector staat onder druk wat betreft dierenwelzijn (o.a. ruimtegebruik in stallen, onverdoofd castreren van biggetjes), internationale economische concurrentie, en mestproblematiek (verzuring, stank). In reactie op deze druk, zijn in beide sectoren radicale innovatietrajecten gestart die systeemcomponenten aanzienlijk veranderen

Regulation of ErbB2 Receptor Status by the Proteasomal DUB POH1

Understanding the factors, which control ErbB2 and EGF receptor (EGFR) status in cells is likely to inform future therapeutic approaches directed at these potent oncogenes. ErbB2 is resistant to stimulus-induced degradation and high levels of over-expression can inhibit EGF receptor down-regulation. We now show that for HeLa cells expressing similar numbers of EGFR and ErbB2, EGFR down-regulation is efficient and insensitive to reduction of ErbB2 levels. Deubiquitinating enzymes (DUBs) may extend protein half-lives by rescuing ubiquitinated substrates from proteasomal degradation or from ubiquitin-dependent lysosomal sorting. Using a siRNA library directed at the full complement of human DUBs, we identified POH1 (also known as Rpn11 or PSMD14), a component of the proteasome lid, as a critical DUB controlling the apparent ErbB2 levels. Moreover, the effects on ErbB2 levels can be reproduced by administration of proteasomal inhibitors such as epoxomicin used at maximally tolerated doses. However, the extent of this apparent loss and specificity for ErbB2 versus EGFR could not be accounted for by changes in transcription or degradation rate. Further investigation revealed that cell surface ErbB2 levels are only mildly affected by POH1 knock-down and that the apparent loss can at least partially be explained by the accumulation of higher molecular weight ubiquitinated forms of ErbB2 that are detectable with an extracellular but not intracellular domain directed antibody. We propose that POH1 may deubiquitinate ErbB2 and that this activity is not necessarily coupled to proteasomal degradation

Forskolin-induced Organoid Swelling is Associated with Long-term CF Disease Progression

RATIONALE: Cystic fibrosis (CF) is a monogenic life-shortening disease associated with highly variable individual disease progression which is difficult to predict. Here we assessed the association of forskolin-induced swelling (FIS) of patient-derived organoids (PDO) with long-term CF disease progression in multiple organs and compared FIS with the golden standard biomarker sweat chloride concentration (SCC). METHODS: We retrieved 9-year longitudinal clinical data from the Dutch CF Registry of 173 people with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Individual CFTR function was defined by FIS, measured as the relative size increase of intestinal organoids after stimulation with 0.8 µM forskolin, quantified as area under the curve (AUC). We used linear mixed effect models and multivariable logistic regression to estimate the association of FIS with long-term FEV1pp decline and development of pancreatic insufficiency, CF-related liver disease and diabetes. Within these models, FIS was compared with SCC. RESULTS: FIS was strongly associated with longitudinal changes of lung function, with an estimated difference in annual FEV1pp decline of 0.32% (95%CI: 0.11%-0.54%; p=0.004) per 1000-points change in AUC. Moreover, increasing FIS levels were associated with lower odds of developing pancreatic insufficiency (adjusted OR: 0.18, 95%CI: 0.07-0.46, p<0.001), CF-related liver disease (adjusted OR: 0.18, 95%CI: 0.06-0.54, p=0.002) and diabetes (adjusted OR: 0.34, 95%CI: 0.12-0.97, p=0.044). These associations were absent for SCC. CONCLUSION: This study exemplifies the prognostic value of a PDO-based biomarker within a clinical setting, which is especially important for people carrying rare CFTR mutations with unclear clinical consequences

The impact of healthcare costs in the last year of life and in all life years gained on the cost-effectiveness of cancer screening

It is under debate whether healthcare costs related to death and in life years gained (LysG) due to life saving interventions should be included in economic evaluations. We estimated the impact of including these costs on cost-effectiveness of cancer screening. We obtained health insurance, home care, nursing homes, and mortality data for 2.1 million inhabitants in the Netherlands in 1998–1999. Costs related to death were approximated by the healthcare costs in the last year of life (LastYL), by cause and age of death. Costs in LYsG were estimated by calculating the healthcare costs in any life year. We calculated the change in cost-effectiveness ratios (CERs) if unrelated healthcare costs in the LastYL or in LYsG would be included. Costs in the LastYL were on average 33% higher for persons dying from cancer than from any cause. Including costs in LysG increased the CER by €4040 in women, and by €4100 in men. Of these, €660 in women, and €890 in men, were costs in the LastYL. Including unrelated healthcare costs in the LastYL or in LYsG will change the comparative cost-effectiveness of healthcare programmes. The CERs of cancer screening programmes will clearly increase, with approximately €4000. However, because of the favourable CER's, including unrelated healthcare costs will in general have limited policy implications

The 20S Proteasome Splicing Activity Discovered by SpliceMet

The identification of proteasome-generated spliced peptides (PSP) revealed a new unpredicted activity of the major cellular protease. However, so far characterization of PSP was entirely dependent on the availability of patient-derived cytotoxic CD8+ T lymphocytes (CTL) thus preventing a systematic investigation of proteasome-catalyzed peptide splicing (PCPS). For an unrestricted PSP identification we here developed SpliceMet, combining the computer-based algorithm ProteaJ with in vitro proteasomal degradation assays and mass spectrometry. By applying SpliceMet for the analysis of proteasomal processing products of four different substrate polypeptides, derived from human tumor as well as viral antigens, we identified fifteen new spliced peptides generated by PCPS either by cis or from two separate substrate molecules, i.e., by trans splicing. Our data suggest that 20S proteasomes represent a molecular machine that, due to its catalytic and structural properties, facilitates the generation of spliced peptides, thereby providing a pool of qualitatively new peptides from which functionally relevant products may be selected