Centenarians exhibit extreme longevity and a remarkable compression of morbidity. They have a unique capacity to maintain homeostatic mechanisms. Since small non-coding RNAs (including microRNAs) are implicated in the regulation of gene expression, we hypothesised that longevity of centenarians may reflect alterations in small non-coding RNA expression. We report the first comparison of microRNAs expression profiles in mononuclear cells from centenarians, octogenarians and young individuals resident near Valencia, Spain. Principal Component Analysis of the expression of 15,644 mature microRNAs and, 2,334 snoRNAs and scaRNAs in centenarians revealed a significant overlap with profiles in young individuals but not with octogenarians and a significant up-regulation of 7 small non-coding RNAs in centenarians compared to young persons and notably 102 small non-coding RNAs when compared with octogenarians. We suggest that the small non-coding RNAs signature in centenarians may provide insights into the underlying molecular mechanisms endowing centenarians with extreme longevity.

Centenarians not only enjoy an extraordinary aging, but also show a compression of morbidity. Using functional transcriptomic analysis of peripheral blood mononuclear cells (PMBC) we identified 1721 mRNAs differentially expressed by centenarians when compared with septuagenarians and young people. Sub-network analysis led us to identify Bcl - xL as an important gene up-regulated in centenarians. It is involved in the control of apoptosis, cellular damage protection and also in modulation of immune response, all associated to healthy aging. Indeed, centenarians display lower plasma cytochrome C levels, higher mitochondrial membrane potential and also less cellular damage accumulation than septuagenarians. Leukocyte chemotaxis and NK cell activity are significantly impaired in septuagenarians compared with young people whereas centenarians maintain them. To further ascertain the functional role of Bcl- xL in cellular aging, we found that lymphocytes from septuagenarians transduced with Bcl-xL display a reduction in senescent-related markers. Finally, to demonstrate the role of BcL-xL in longevity at the organism level, C. elegans bearing a gain of function mutation in the BcL-xL ortholog ced-9, showed a significant increase in mean and maximal life span. These results show that mRNA expression in centenarians is unique and reveals that BcL- xL plays an important role in exceptional aging.

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Traumatic brain injury (TBI) is a major health problem with high rates of mortality and morbidity worldwide. The response of the brain to TBI is orchestrated by a number of cytokines, including interleukin‐6 (IL‐6). IL‐6 is a major cytokine in the central nervous system and it is produced by different cells, such as neurons, glial cells, and endothelial cells. Since glial cells are one of the most important sources and targets of IL‐6, we have examined the role of microglia‐derived IL‐6 in normal conditions and following a model of TBI, cryolesion of the somatosensorial cortex. To this end, tamoxifen‐inducible microglial IL‐6‐deficient (Il6ΔMic, using Cx3cr1 CreER model) mice and control (Il6lox/lox) mice were used. In normal conditions, microglial IL‐6 deficiency reduced deambulation and exploratory behavior and decreased anxiety in a sex‐dependent manner. The transcriptome profile following cryolesion was dramatically altered 1 day post‐lesion in Il6ΔMic compared with Il6lox/lox mice. However, the phenotype of Il6ΔMic mice was less compromised in the following days, suggesting that compensatory mechanisms are at play.

Background/Aims: Interleukin-6 (IL-6) is a major cytokine controlling body weight and metabolism, at least in part through actions in the central nervous system (CNS) from local sources. Methods: We herewith report results obtained in conditional IL-6 KO mice for brain cells (Il6ΔGfap and Il6ΔSyn). Results: The reporter RiboTag mouse line demonstrated specific astrocytic expression of GFAP-dependent Cre in the hypothalamus but not in other brain areas, whereas that of synapsin 1-dependent Cre was specific for neurons. Feeding a high-fat diet (HFD) or a control diet showed that Il6ΔGfap and Il6ΔSyn mice were more prone and resistant, respectively, to HFD-induced obesity. Energy intake was not altered in HFD experiments, but it was reduced in Il6ΔSyn male mice following a 24-h fast. HFD increased circulating insulin, leptin, and cholesterol levels, decreased triglycerides, and caused impaired responses to the insulin and glucose tolerance tests. In Il6ΔGfap mice, the only significant difference observed was an increase in insulin levels of females, whereas in Il6ΔSyn mice the effects of HFD were decreased. Hypothalamic Agrp expression was significantly decreased by HFD, further decreased in Il6ΔGfap, and increased in Il6ΔSyn female mice. Hypothalamic Il-6 mRNA levels were not decreased in Il6ΔSyn mice and even increased in Il6ΔGfapmale mice. Microarray analysis of hypothalamic RNA showed that female Il6ΔGfap mice had increased interferon-related pathways and affected processes in behavior, modulation of chemical synaptic transmission, learning, and memory. Conclusion: The present results demonstrate that brain production of IL-6 regulates body weight in the context of caloric excess and that the cellular source is critical.