Project description:Aging human skin undergoes significant morphological and functional changes such as wrinkle formation, reduced wound healing capacity, and altered epidermal barrier function. Besides known age-related alterations like DNA-methylation changes, metabolic adaptations have been more recently linked to impaired skin function in old humans. Understanding of these metabolic adaptations in aged skin are of special interest, because topical treatments could reverse age-dependent metabolic changes of human skin in vivo to affect age associated skin disorders. Results: We investigated the global metabolic adaptions in human skin during aging with a combined transcriptomic and metabolomic approach applied to epidermal tissue samples of young and old human volunteers. Our analysis confirmed known age-dependent metabolic alterations, e.g. reduction of coenzyme Q10 levels, and also revealed novel age effects that are seemingly important for skin maintenance. Integration of donor-matched transcriptome and metabolome data highlighted transcriptionally-driven alterations of metabolism during aging such as altered activity in upper glycolysis and glycerolipid biosynthesis or decreased protein and polyamine biosynthesis. Together, we identified several age-dependent metabolic alterations that might affect cellular signaling, epidermal barrier function, and skin structure and morphology. Conclusion: Our study provides a global resource on the metabolic adaptations and its transcriptional regulation during aging of human skin. Thus, it represents a first step towards an understanding of the impact of metabolism on impaired skin function in aged humans and therefore will potentially lead to improved treatments of age related skin disorders
Project description:Peptides function as signaling molecules in species as diverse as humans and yeast. Mass spectrometry-based peptidomics techniques provide a relatively unbiased method to assess the peptidome of biological samples. In the present study, we used a quantitative peptidomic technique to characterize the peptidome of the yeast Saccharomyces cerevisiae and compare it to the peptidomes of mammalian cell lines and tissues. Altogether, 297 yeast peptides derived from 75 proteins were identified. The yeast peptides are similar to those of the human peptidome in average size and amino acid composition. Inhibition of proteasome activity with either bortezomib or epoxomicin led to decreased levels of some yeast peptides, suggesting that these peptides are generated by the proteasome. Approximately 30% of the yeast peptides correspond to the N- or C-terminus of the protein; the human peptidome is also highly represented in N- or C-terminal protein fragments. Most yeast and humans peptides are derived from a subset of abundant proteins, many with functions involving cellular metabolism or protein synthesis and folding. Of the 75 yeast proteins that give rise to peptides, 24 have orthologs that give rise to human and/or mouse peptides and for some, the same region of the proteins are found in the human, mouse, and yeast peptidomes. Taken together, these results support the hypothesis that intracellular peptides may have specific and conserved biological functions.
Project description:The evolutionarily conserved Origin Recognition Complex (ORC), plays a key role in origin selection in eukaryotes. However, ORC is strikingly divergent in its DNA binding specificity, ranging from base-specific interactions in Saccharomyces cerevisiae to base-agnostic interactions in humans. The mechanisms underlying this distinct selectivity is unknown. Atomic model of the yeast ORC showed that base-specific interaction with the invariant thymines of the ARS consensus sequence (ACS) is encoded by a 19-amino acid insertion helix (IH) embedded in the winged helix domain (WHD) of Orc4. This IH is absent in the Orc4 of metazoans including humans, suggesting that removal of the IH might give the yeast ORC “human-like” properties. Indeed, yeast strain engineered with IH deficient Orc4 has completely altered ORC-binding sites enriched in poly-dT tracts located in larger nucleosome-depleted and intergenic open chromatin. In vivo and in vitro assays show that the mutant ORC loads MCM efficiently, in spite of its altered specificity in favor of binding patterns more characteristic of those observed in humans/metazoans. This work provides insights for understanding how ORC evolves to adopt a life cycle that requires plasticity in origin selection during development.
Project description:The purpose of this study was to determine whether there were differences in gene expression in the hippocampus, a part of the brain involved in memory consolidation, between male mice with age-related memory deficits (SAMP8 mice) and control mice with no age-related memory deficits. The senescence-accelerated mouse (SAMP8) strain exhibits decreased learning and memory and increased amyloid beta peptide (Aβ) accumulation at 12 months compared to 4 months. To detect differences in gene expression in SAMP8 mice, we used a Control mouse that was a 50% cross between SAMP8 and CD-1 mice and which showed no memory deficits (50% SAMP8 mouse). We then compared gene expression in the hippocampus of 4 month and 12 month old SAMP8 and Control mice using Affymetrix gene arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself. Global differential profiling of hippocampal gene expression (4 month and 12 month old SAMP8 and Control mice) was performed using Affymetrix GeneChip® Mouse Genome 430 2.0 Arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself. 2-way ANOVA (2 x 2 conditions, n=4). First variable was age (4 and 12 months) and second variable was mouse strain (Control and SAMP8). This results in 4 groups: Control-4 month, Control-12 month, SAMP8-4 month, and SAMP8-12 month. Each group had 4 biological replicates (4 mice). The ”Control” mice were a 50% backcross of the SAMP8 mice with CD-1 mice (50% SAMP8 mice). These mice were closely related to SAMP8 mice but exhibited no memory deficits at 4 or 12 months. The SAMP8 mice had memory deficits at 12 months but not at 4 months.
Project description:We found that NDK-1/NDPK functions together with DYN-1/Dynamin to trigger membrane remodeling events during apoptotic cell clearance, including engulfment and phagosome maturation. We showed by IP-Mass Spec studies that C. elegans NDK-1/NDPK and DYN-1/Dynamin function in the same complex.
Project description:Failure of neural stem/progenitor cell (NSPC) activity and subsequently neurogenesis during brain development has been linked to cognitive impairment and intellectual disability. However, it remains unclear if changes in metabolism, recently discovered as a key regulator of somatic stem cell activity, contribute to altered neurogenesis and cognitive deficits in humans. To investigate a link between NSPC-associated lipid metabolism and brain development, we generated mice and human embryonic stem cells (hESCs) mimicking a variant in fatty acid synthase (FASN; R1819W), a metabolic regulator of rodent NSPC activity recently identified in humans with intellectual disability. Mice homozygous for the FASN R1812W variant have impaired hippocampal NSPC activity associated with cognitive impairment due to presumed toxic accumulation of lipids in NSPCs and subsequent lipogenic ER stress. Human NSPCs homozygous for the FASN R1819W variant show reduced rates of proliferation in embryonic 2D cultures and 3D forebrain regionalized organoids, revealing that the functional significance of lipid metabolism for neurogenic proliferation of progenitors is conserved between rodents and humans. By taking a disease modeling approach, using mouse and human tissue genome engineering, our data provide genetic evidence for a link between altered lipid metabolism, NSPC activity and brain function.
Project description:Because of their similarity to humans, non-human primates are important models for studying human disease and developing therapeutic strategies. Establishment of chimeric animals using embryonic stem cells (ESCs) could help with these investigations, but has not so far been achieved. Here, we show that cynomolgus monkey ESCs (cESCs) grown in adjusted culture conditions are able to incorporate into host embryos and develop into chimeras with contribution in all three germ layers and in germ cell progenitors. Under the optimized culture conditions, which are based on an approach developed previously for naive human ESCs, the cESCs displayed altered growth properties, gene expression profiles and self-renewal signaling pathways, suggestive of an altered naive-like cell state. Thus our findings show that it is feasible to generate chimeric monkeys using ESCs and open up new avenues for the use of non-human primate models to study both pluripotency and human disease.
Project description:DNA methyltransferase inhibitors (DNMTi) has been shown to modulate pathways related to antigen processing/presentation, human leukocyte antigens (HLA), and interferon responses across different cancer types on the transcriptomic level (Li et al., 2014; Wrangle et al., 2013). Nevertheless, these transcriptomic changes may not fully reflect the alterations of surface proteins that provoke susceptibility to immunotherapy. Thus, we sought to obtain a comprehensive profile of surface proteins altered by decitabine (DAC) through isolating cell surface proteins from A549 human lung cancer cells before and after DAC treatment using EZ-link Sulfo-NHS-SS-Biotin-assisted biotinylation method, followed by SILAC-based quantitative proteomics approach.
Project description:During the evolution of vertebrates, specific molecular innovations ensured adaptations which resulted in the split of different animal groups. Here comparative genomic analysis became a valued instrument to identify genes associated with the divergence of taxa and speciation events. Using this approach, we identified the association of the previously uncharacterized gene (mouse (1700011H14RIK, human C14ORF105/CCDC198), hereby named Kamp (Kidney-associated membrane protein) with the evolutionary split leading to birds and mammals. Furthermore, by comparing single nuclear polymorphisms of modern humans with Neandertals at the locus of Kamp, we identified gene-flow of Kamp from Neandertals into modern humans. Analyzing the expression of Kamp in humans revealed a restriction to the kidney, pancreas, and few other organs. A knockout of this gene in mice resulted in a structurally normal kidney as validated with micro-computed microtomography scans and single-cell transcriptomics, but with higher Albumin levels in the urine lower serum ferritin levels. Further, interactomics screening revealed an interaction between KAMP and ferritin (heavy chain), which was cross-validated by the analysis of co-localization of both proteins in vesicular and plasma membranes. The membranal localization of KAMP appeared regulated by its N-terminal myristoylation site, as KAMP became cytoplasmic in the absence of this specific sequence. Kamp knockout animals demonstrated increased body weight and decreased energy expenditure. This corresponded to Genome-Wide Association Studies of Kamp linked with higher BMI, diabetes-related pathologies, and macular degeneration in humans. Subsequent gain-of-function experiments showed altered proliferative dynamics and accumulation of KAMP during mitosis. Bioinformatics analysis indicated a protective role of KAMP in renal and liver cancer progression, as suggested by an association of KAMP with epithelial-to-mesenchymal transition and altered localization in tumors versus healthy tissue. Altogether, our results revealed several important roles played by KAMP in a vertebrate body, with specific emphasis on metabolite excretion and energy expenditure.