Aging is a complex process that can be characterized by functional and cognitive decline in an individual. Aging can be assessed based on the functional capacity of vital organs and their intricate interactions with one another. Thus, the nature of aging can be described by focusing on a specific organ and an individual itself. However, to fully understand the complexity of aging, one must investigate not only a single tissue or biological process but also its complex interplay and interdependencies with other biological processes. Here, using RNA-seq, we monitored changes in the transcriptome during aging in four tissues (including brain, blood, skin and liver) in mice at 9 months, 15 months, and 24 months, with a final evaluation at the very old age of 30 months. We identified several genes and processes that were differentially regulated during aging in both tissue-dependent and tissue-independent manners. Most importantly, we found that the electron transport chain (ETC) of mitochondria was similarly affected at the transcriptome level in the four tissues during the aging process. We also identified the liver as the tissue showing the largest variety of differentially expressed genes (DEGs) over time. Lcn2 (Lipocalin-2) was found to be similarly regulated among all tissues, and its effect on longevity and survival was validated using its orthologue in Caenorhabditis elegans. Our study demonstrated that the molecular processes of aging are relatively subtle in their progress, and the aging process of every tissue depends on the tissue’s specialized function and environment. Hence, individual gene or process alone cannot be described as the key of aging in the whole organism.

The circadian clock system influences the biology of life by establishing circadian rhythms in organisms, tissues, and cells, thus regulating essential biological processes based on the day/night cycle. Circadian rhythms change over a lifetime due to maturation and aging, and disturbances in the control of the circadian system are associated with several age-related pathologies.

Background: The short-lived fishNothobranchius furzeriis the shortest-lived vertebrate that can be cultured in captivity and was recently established as a model organism for aging research. Small non-coding RNAs, especially miRNAs, are implicated in age dependent control of gene expression.Results: Here, we present a comprehensive catalogue of miRNAs and several other non-coding RNA classes (ncRNAs) forNothobranchius furzeri. Analyzing multiple small RNA-Seq libraries, we show most of these identified miRNAs are expressed in at least one of sevenNothobranchiusspecies. Additionally, duplication and clustering ofN. furzerimiRNAs was analyzed and compared to the four fish speciesDanio rerio,Oryzias latipes,Gasterosteus aculeatusandTakifugu rubripes. A peculiar characteristic ofN. furzeri, as compared to other teleosts, was a duplication of the miR-29 cluster.Conclusion: The completeness of the catalogue we provide is comparable to that of the zebrafish. This catalogue represents a basis to investigate the role of miRNAs in aging and development in this species.

Diatoms (Bacillariophyceae) are a major constituent of the phytoplankton and have a universally recognized ecological importance. Between 1,000 and 1,300 diatom genera have been described in the literature, but only 10 nuclear genomes have been published and made available to the public up to date. Skeletonema costatum is a cosmopolitan marine diatom, principally occurring in coastal regions, and is one of the most abundant members of the Skeletonema genus. Here we present a draft assembly of the Skeletonema cf. costatum RCC75 genome, obtained from PacBio and Illumina NovaSeq data. This dataset will expand the knowledge of the Bacillariophyceae genetics and contribute to the global understanding of phytoplankton's physiological, ecological, and environmental functioning.

Understanding the process of aging is still an important challenge to enable healthy aging and to prevent age-related diseases. Most studies in age research investigate the decline in organ functionality and gene activity with age. The focus on decline can even be considered a paradigm in that field. However, there are certain aspects that remain surprisingly stable and keep the organism robust. Here, we present and discuss various properties of robust behavior during human and animal aging, including physiological and molecular biological features, such as the hematocrit, body temperature, immunity against infectious diseases and others. We examine, in the context of robustness, the different theories of how aging occurs. We regard the role of aging in the light of evolution.

Drug delivery to the brain is challenging due to the restrict permeability of the blood brain barrier (BBB). Recent studies indicate that BBB permeability increases over time during physiological aging likely due to factors (including extracellular vesicles (EVs)) that exist in the bloodstream. Therefore, inspiration can be taken from aging to develop new strategies for the transient opening of the BBB for drug delivery to the brain. Here, we evaluated the impact of small EVs (sEVs) enriched with microRNAs (miRNAs) overexpressed during aging, with the capacity to interfere transiently with the BBB. Initially, we investigated whether the miRNAs were overexpressed in sEVs collected from plasma of aged individuals. Next, we evaluated the opening properties of the miRNA-enriched sEVs in a static or dynamic (under flow) human in vitro BBB model. Our results showed that miR-383-3p-enriched sEVs significantly increased BBB permeability in a reversible manner by decreasing the expression of claudin 5, an important tight junction protein of brain endothelial cells (BECs) of the BBB, mediated in part by the knockdown of activating transcription factor 4 (ATF4). Our findings suggest that engineered sEVs have potential as a strategy for the temporary BBB opening, making it easier for drugs to reach the brain when injected into the bloodstream.