Liver carcinogenesis by FOS-dependent inflammation and cholesterol dysregulation

233294Human hepatocellular carcinomas (HCCs), which arise on a background of chronic liver damage and inflammation, express c-Fos, a component of the AP-1 transcription factor. Using mouse models, we show that hepatocyte-specific deletion of c-Fos protects against diethylnitrosamine (DEN)-induced HCCs, whereas liver-specific c-Fos expression leads to reversible premalignant hepatocyte transformation and enhanced DEN-carcinogenesis. c-Fos-expressing livers display necrotic foci, immune cell infiltration, and altered hepatocyte morphology. Furthermore, increased proliferation, dedifferentiation, activation of the DNA damage response, and gene signatures of aggressive HCCs are observed. Mechanistically, c-Fos decreases expression and activity of the nuclear receptor LXRα, leading to increased hepatic cholesterol and accumulation of toxic oxysterols and bile acids. The phenotypic consequences of c-Fos expression are partially ameliorated by the anti-inflammatory drug sulindac and largely prevented by statin treatment. An inverse correlation between c-FOS and the LXRα pathway was also observed in human HCC cell lines and datasets. These findings provide a novel link between chronic inflammation and metabolic pathways important in liver cancer.We thank Drs. N. Djouder, M. Petruzzelli, R. Ricci, F.X Real, K.D. Bissig, and members of the Wagner laboratory for critical reading of the manuscript and valuable sugges- tions; Dr. H. Schönthaler for help with the bioinformatics analysis; V. Bermeo for technical help; and G. Luque, S. Leceta, and G. Medrano for assisting with mouse experiments. The E.F. Wagner laboratory is supported by grants from the Spanish Ministry of Economy, Industry, and Competitiveness (BFU2012-40230 and SAF2015-70857, co- funded by the European Regional Development Fund), a European Research Council– advanced grant (ERC-FCK/2008/37), and Worldwide Cancer Research (13-0216). R. Hamacher was supported by the Deutsche Forschungsgemeinschaft (HA 6068/1-1), M.K. Thomsen by AUFF Nova, and S.C. Hasenfuss by a Boehringer Ingelheim Fonds PhD fellowship. The authors declare no competing financial interests. Author contributions: L. Bakiri and R. Hamacher designed and performed exper- iments, analyzed data, prepared figures, and wrote the manuscript. O. Graña analyzed RNA-seq and public microarray data, A. Guío-Carrión provided expert technical assis- tance, R. Campos-Olivas acquired and analyzed NMR data, L. Martinez analyzed flow cytometry data, M.K. Thomsen performed experiments with human cell lines, S.C. Hasenfuss performed experiments with primary hepatocytes and data mining, and H.P. Dienes performed pathological analysis on tissue sections. E.F. Wagner directed the study, approved the data, and wrote and edited the paper. All authors read and commented on the manuscript.S

Small extracellular vesicles from young adipose-derived stem cells prevent frailty, improve health span, and decrease epigenetic age in old mice.

Aging is associated with an increased risk of frailty, disability, and mortality. Strategies to delay the degenerative changes associated with aging and frailty are particularly interesting. We treated old animals with small extracellular vesicles (sEVs) derived from adipose mesenchymal stem cells (ADSCs) of young animals, and we found an improvement in several parameters usually altered with aging, such as motor coordination, grip strength, fatigue resistance, fur regeneration, and renal function, as well as an important decrease in frailty. ADSC-sEVs induced proregenerative effects and a decrease in oxidative stress, inflammation, and senescence markers in muscle and kidney. Moreover, predicted epigenetic age was lower in tissues of old mice treated with ADSC-sEVs and their metabolome changed to a youth-like pattern. Last, we gained some insight into the microRNAs contained in sEVs that might be responsible for the observed effects. We propose that young sEV treatment can promote healthy aging

Dynamics of telomeric repeat-containing RNA expression in early embryonic cleavage stages with regards to maternal age.

Telomeres are transcribed into long non-coding RNAs known as Telomeric Repeat-Containing RNA (TERRA). They have been shown to be essential regulators of telomeres and to act as epigenomic modulators at extra-telomeric sites. However the role of TERRA during early embryonic development has never been investigated. Here, we show that TERRA is expressed in murine and bovine early development following a wave pattern. It starts at 4-cell stage, reaching a maximum at the 16-cell followed by a decline at the morula and blastocyst stages. Moreover, TERRA expression is not affected by increasing oocyte donor age whereas telomere length does. This indicates that TERRA expression is independent of the telomere length in early development. Our findings anticipate an essential role of TERRA in early stages of development and this might be useful in the future for a better understanding of age related female infertility.Dr P. Kordowitzki was supported by KNOW consortium (Poland MS&HE, Decision No. 05-1/KNOW2/2015) and by a special statutory fund of DRI&P IAR&FR PAS in Olsztyn. The support of Sagrario Ortega and co-workers is gratefully acknowledged. Research in the Blasco Lab is funded by the Spanish Ministry of Economy and Competitiveness Projects (SAF2013-45111-R and SAF2015-72455-EXP), the Comunidad de Madrid Project (S2017/BMD-3770), the World Cancer Research (WCR) Project (16-1177), and the Fundacion Botin (Spain).S

Shorter telomere lengths in patients with severe COVID-19 disease.

The incidence of severe manifestations of COVID-19 increases with age with older patients showing the highest mortality, suggesting that molecular pathways underlying aging contribute to the severity of COVID-19. One mechanism of aging is the progressive shortening of telomeres, which are protective structures at chromosome ends. Critically short telomeres impair the regenerative capacity of tissues and trigger loss of tissue homeostasis and disease. The SARS-CoV-2 virus infects many different cell types, forcing cell turn-over and regeneration to maintain tissue homeostasis. We hypothesize that presence of short telomeres in older patients limits the tissue response to SARS-CoV-2 infection. We measure telomere length in peripheral blood lymphocytes COVID-19 patients with ages between 29 and 85 years-old. We find that shorter telomeres are associated to increased severity of the disease. Individuals within the lower percentiles of telomere length and higher percentiles of short telomeres have higher risk of developing severe COVID-19 pathologies.We thank D. Megias and G. Mata for their help in confocal microscopy. Research in the Blasco lab is funded by the Spanish Ministry of Science and Innovation Projects (SAF2017-82623-R and SAF2015-72455-EXP), the Comunidad de Madrid Project (B2017/BMD-3770), the World Cancer Research (WCR) Project (16-1177) and the Fundacion Botin (Spain). R.S-V is a recipient of a doctoral scholarship from CONACYT-Mexico.S