Project description:Aging, particularly in the brain, involves impairments in multiple cellular and molecular functions, many of which are regulated at the nucleus. Chromatin structure plays a critical role in the regulation of gene expression and the maintenance of genomic stability. During differentiation, chromosomes acquire their unique topology depending on the cell type that should be kept for a lifetime, but this may deteriorate as we age. However, the effects of aging on the chromatin 3D structure of neurons remain largely unknown and much has been inferred from senescent cells. By combining chromosome conformation capture and microscopy techniques, we investigated cortical neurons of young and aged mice and discovered neuronal nuclear expansion during neuronal aging, leading to increased distances between chromosomes. This expansion alters the topology of compartments, topologically associating domains (TADs) and chromatin loops. While larger TADs tend to dissociate, smaller TADs and loops exhibit strengthened interactions to maintain the cohesiveness of chromatin in aged neurons. These topological changes impact the borders of TADs, resulting in their overall weakening. Interestingly, we attribute these alterations to changes in the physical forces of an expanding nucleus, filling a growing nuclear area, affecting downstream gene expression and chromatin topology, further contributing to the functional declines observed during aging.
Project description:Hematopoietic aging is defined by a loss of regenerative capacity and skewed differentiation from hematopoietic stem cells (HSC) leading to dysfunctional blood production. Signals from the bone marrow (BM) microenvironment dynamically tailor hematopoiesis, but the effect of aging on the niche and the contribution of the aging niche to blood aging still remains unclear. Here, we show the development of an inflammatory milieu in the aged marrow cavity, which drives both niche and hematopoietic system remodeling. We find decreased numbers and functionality of osteogenic endosteal mesenchymal stromal cells (MSC), expansion of pro-inflammatory perisinusoidal MSCs, and deterioration of the central marrow sinusoidal endothelium, which together create a self-reinforcing inflamed BM milieu. Single cell molecular mapping of old niche cells further confirms disruption of cell identities and enrichment of inflammatory response genes. Inflammation, in turn, drives chronic activation of emergency myelopoiesis pathways in old HSCs and multipotent progenitors, which promotes myeloid differentiation at the expense of lymphoid and erythroid commitment, and hinders hematopoietic regeneration. Remarkably, both defective hematopoietic regeneration, niche deterioration and HSC aging can be improved by blocking inflammatory IL-1 signaling. Our results indicate that targeting the pro-inflammatory niche milieu can be instrumental in restoring blood production during aging.
Project description:Impaired extracellular matrix (ECM) remodeling is a hallmark of many chronic inflammatory disorders that can lead to cellular dysfunction, aging, and disease progression. The ECM of the aged heart and its effects on cardiac cells during chronological and pathological aging are relatively poorly understood in several speciesacross species. Here, we used mass spectrometry-based proteomics to quantitatively characterize age-related remodeling of the left ventricle (LV) of mice and humans during chronological and pathological (Hutchinson-Gilford progeria syndrome (HGPS)) aging. Of the approximately 300 ECM proteins quantified, we identified 13 proteins that were increased, including lactadherin (MFGE8), collagen VI 6 (COL6A6), vitronectin (VTN) and immunoglobulin heavy constant mu (IGHM), whereas fibulin-5 (FBLN5) was decreased in most of the data sets analyzed. We show that lactadherin accumulates with age in large cardiac blood vessels and when immobilized, triggers phosphorylation of several phosphosites of GSK3B, MAPK isoforms 1, 3, and 14, and MTOR kinases in aortic endothelial cells (ECs). In addition, immobilized lactadherin increased the expression of pro-inflammatory markers associated with an aging phenotype. These results extend our knowledge of the LV proteome remodeling induced by chronological and pathological aging in different species (mouse and human). The lactadherin-triggered changes in the proteome and phosphoproteome of ECs suggest a straight link between ECM component remodeling and the aging process of ECs.
Project description:Impaired extracellular matrix (ECM) remodeling is a hallmark of many chronic inflammatory disorders that can lead to cellular dysfunction, aging, and disease progression. The ECM of the aged heart and its effects on cardiac cells during chronological and pathological aging are poorly understood across species. Here, we used mass spectrometry-based proteomics to quantitatively characterize age-related remodeling of the left ventricle (LV) of mice and humans during chronological and pathological (Hutchinson-Gilford progeria syndrome (HGPS)) aging. Of the approximately 300 ECM proteins quantified, we identified 13 proteins that were increased, including lactadherin (MFGE8), collagen VI 6 (COL6A6), vitronectin (VTN) and immunoglobulin heavy constant mu (IGHM), whereas fibulin-5 (FBLN5) was decreased in most of the data sets analyzed. We show that lactadherin accumulates with age in large cardiac blood vessels and when immobilized, triggers phosphorylation of several phosphosites of GSK3B, MAPK isoforms 1, 3, and 14, and MTOR kinases in aortic endothelial cells (ECs). In addition, immobilized lactadherin increased the expression of pro-inflammatory markers associated with an aging phenotype. These results extend our knowledge of the LV proteome remodeling induced by chronological and pathological aging in different species (mouse and human). The lactadherin-triggered changes in the proteome and phosphoproteome of ECs suggest a straight link between ECM component remodeling and the aging process of ECs.
Project description:To gain an understanding of processes that underlie chronological aging in this dinoflagellate, a microarray study was carried out to identify changes in the global transcriptome that accompany the entry and maintenance of stationary phase up to the onset of cell death. The transcriptome of K. brevis was assayed using a custom 10,263 feature oligonucleotide microarray from mid-logarithmic growth to the onset of culture demise. A total of 2,958 (29%) features were differentially expressed, with the mid-stationary phase timepoint demonstrating peak changes in expression. Gene ontology enrichment analyses identified a significant shift in transcripts involved in energy acquisition, ribosome biogenesis, gene expression, stress adaptation, calcium signaling, and putative brevetoxin biosynthesis. The extensive remodeling of the transcriptome observed in the transition into a quiescent non-dividing phase appears to be indicative of a global shift in the metabolic and signaling requirements and provides the basis from which to understand the process of chronological aging in a dinoflagellate. Twenty seven 900ml batch cultures of K. brevis were inoculated at a starting concentration of approximately 1000 cells/ml from mid-logarithmic stage starter cultures on day 0. Triplicate cultures were harvested every other day from day 2 to 18 and total RNA was extracted. One color arrays were then run on all biological replicates (n=3 at each timepoint) for days 4, 6, 10, 14 and 18.
Project description:Driver mutated clones multi-focally emerged from early adulthood and over years, increase their number and size, ultimately remodeling the entire esophageal epithelia in extreme elderly. Our results suggest that clonal expansion in esophageal epithelia is an inevitable consequence of normal aging, differentially impacting the development of cancer depending on mutation type and exposure to drinking and smoking.
Project description:The human heart is capable of functioning for decades despite minimal cell turnover or regeneration, suggesting that molecular alterations help sustain heart function with age. However, identification of compensatory remodeling events in the aging heart remains elusive. Here we present the proteomes of rhesus monkeys and rats, from which we show that age-associated remodeling of the cardiomyocyte cytoskeleton is highly-conserved and beneficial rather than deleterious. Targeted transcriptomic analysis in Drosophila confirms conservation and implicates vinculin as a unique regulator of cardiac aging. Increased cardiac vinculin expression reinforced the cortical cytoskeleton and enhanced myofilament organization, leading to improved contractility, hemodynamic stress tolerance, and lifespan. These findings suggest that the heart has molecular mechanisms to sustain function and longevity which may be assisted by therapeutic intervention.