Cell stemness is maintained upon concurrent expression of RB and the mitochondrial ribosomal protein S18-2

Stemness encompasses the capability of a cell for self-renewal and differentiation. The stem cell maintains a balance between proliferation, quiescence, and regeneration via interactions with the microenvironment. Previously, we showed that ectopic expression of the mitochondrial ribosomal protein S18-2 (MRPS18-2) led to immortalization of primary fibroblasts, accompanied by induction of an embryonic stem cell (ESC) phenotype. Moreover, we demonstrated interaction between S18-2 and the retinoblastoma-associated protein (RB) and hypothesized that the simultaneous expression of RB and S18-2 is essential for maintaining cell stemness. Here, we experimentally investigated the role of S18-2 in cell stemness and differentiation. Concurrent expression of RB and S18-2 resulted in immortalization of Rb1−/− primary mouse embryonic fibroblasts and in aggressive tumor growth in severe combined immunodeficiency mice. These cells, which express both RB and S18-2 at high levels, exhibited the potential to differentiate into various lineages in vitro, including osteogenic, chondrogenic, and adipogenic lineages. Mechanistically, S18-2 formed a multimeric protein complex with prohibitin and the ring finger protein 2 (RNF2). This molecular complex increased the monoubiquitination of histone H2ALys119, a characteristic trait of ESCs, by enhanced E3-ligase activity of RNF2. Furthermore, we found enrichment of KLF4 at the S18-2 promoter region and that the S18-2 expression is positively correlated with KLF4 levels. Importantly, knockdown of S18-2 in zebrafish larvae led to embryonic lethality. Collectively, our findings suggest an important role for S18-2 in cell stemness and differentiation and potentially also in cancerogenesis

The HEATOX project

HEATOX is the acronym for a European Union-funded project entitled Heat-Generated Food Toxicants: Identification, Characterization, and Risk Minimization. Acrylamide will be the main experimental focus, but identification of unknown toxicants in heated carbohydrate-rich foods will also be attempted. The project includes research on formation chemistry, food technology, analytical methods, hazard characterization, and exposure assessment. The results will finally be used in risk assessment and risk management advice

Complement Gene Single Nucleotide Polymorphisms and Biomarker Endophenotypes of Alzheimer\u27s Disease

The complement system has been implicated in both physiological synapse elimination and Alzheimer\u27s disease (AD). Here, we investigated associations between four single nucleotide polymorphisms (SNPs) in complement genes and cerebrospinal fluid (CSF) biomarkers for AD in 452 neurochemically or neuropathologically verified AD cases and 678 cognitively normal controls. None of the SNPs associated with risk of AD but there were potential associations of rs9332739 in the C2 gene and rs4151667 in the complement factor B gene with CSF tau levels (p = 0.023) and Mini-Mental State Examination scores (p = 0.012), both of which may be considered markers of disease intensity/severity

Exposure to disinfection by-products in swimming pools and biomarkers of genotoxicity and respiratory damage - The PISCINA2 Study

BACKGROUND: Swimming in pools is a healthy activity that entails exposure to disinfection by-products (DBPs), some of which are irritant and genotoxic. OBJECTIVES: We evaluated exposure to DBPs during swimming in a chlorinated pool and the association with short-term changes in genotoxicity and lung epithelium permeability biomarkers. METHODS: Non-smoker adults (N = 116) swimming 40 min in an indoor pool were included. We measured a range of biomarkers before and at different times after swimming: trihalomethanes (THMs) in exhaled breath (5 min), trichloroacetic acid (TCAA) in urine (30 min), micronuclei in lymphocytes (1 h), serum club cell protein (CC16) (1 h), urine mutagenicity (2 h) and micronuclei in reticulocytes (4 days in a subset, N = 19). Several DBPs in water and trichloramine in air were measured, and physical activity was extensively assessed. We estimated interactions with polymorphisms in genes related to DBP metabolism. RESULTS: Median level of chloroform, brominated and total THMs in water was 37.3, 9.5 and 48.5, μg/L, respectively, and trichloramine in air was 472.6 μg/m3. Median exhaled chloroform, brominated and total THMs increased after swimming by 10.9, 2.6 and 13.4, μg/m3, respectively. Creatinine-adjusted urinary TCAA increased by 3.1 μmol/mol. Micronuclei in lymphocytes and reticulocytes, urine mutagenicity and serum CC16 levels remained unchanged after swimming. Spearman correlation coefficients showed no association between DBP exposure and micronuclei in lymphocytes, urine mutagenicity and CC16. Moderate associations were observed for micronuclei in reticulocytes and DBP exposure. CONCLUSIONS: The unchanged levels of the short-term effect biomarkers after swimming and null associations with personal estimates of exposure to DBPs suggest no measurable effect on genotoxicity in lymphocytes, urine mutagenicity and lung epithelium permeability at the observed exposure levels. The moderate associations with micronuclei in reticulocytes require cautious interpretation given the reduced sample size.We are grateful to all volunteers and the swimming pool facility. This work was funded by the EU 7th Framework Programme EXPOSOMICS Project (grant agreement 308610). We thank the Parc de Salut Mar Biobank (MARBiobanc) for providing support to the project. MARBiobanc is supported by grants from Instituto de Salud Carlos III/FEDER (RD09/0076/00036 and PT13/0010/0005) and the “Xarxa de Bancs de tumors” sponsored by Pla Director d'Oncologia de Catalunya (XBTC). ISGlobal is a member of the CERCA Programme, Generalitat de Catalunya. We appreciate the work by Kate Jones (Health & Safety Laboratory, UK) for urinary TCAA analysis