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Science China. Life Sciences Mar 2024Cullin-RING E3 ubiquitin ligases (CRLs), the largest family of multi-subunit E3 ubiquitin ligases in eukaryotic cells, represent core cellular machinery for executing...
Cullin-RING E3 ubiquitin ligases (CRLs), the largest family of multi-subunit E3 ubiquitin ligases in eukaryotic cells, represent core cellular machinery for executing protein degradation and maintaining proteostasis. Here, we asked what roles Cullin proteins play in human mesenchymal stem cell (hMSC) homeostasis and senescence. To this end, we conducted a comparative aging phenotype analysis by individually knocking down Cullin members in three senescence models: replicative senescent hMSCs, Hutchinson-Gilford Progeria Syndrome hMSCs, and Werner syndrome hMSCs. Among all family members, we found that CUL2 deficiency rendered hMSCs the most susceptible to senescence. To investigate CUL2-specific underlying mechanisms, we then applied CRISPR/Cas9-mediated gene editing technology to generate CUL2-deficient human embryonic stem cells (hESCs). When we differentiated these into hMSCs, we found that CUL2 deletion markedly accelerates hMSC senescence. Importantly, we identified that CUL2 targets and promotes ubiquitin proteasome-mediated degradation of TSPYL2 (a known negative regulator of proliferation) through the substrate receptor protein APPBP2, which in turn down-regulates one of the canonical aging marker-P21, and thereby delays senescence. Our work provides important insights into how CRL2-mediated TSPYL2 degradation counteracts hMSC senescence, providing a molecular basis for directing intervention strategies against aging and aging-related diseases.
Topics: Humans; Carrier Proteins; Cellular Senescence; Cullin Proteins; Mesenchymal Stem Cells; Ubiquitin-Protein Ligases; Ubiquitins
PubMed: 38170390
DOI: 10.1007/s11427-023-2451-3 -
BioRxiv : the Preprint Server For... Jan 2024Abnormalities in the shapes of mammalian cell nuclei are hallmarks of a variety of diseases, including progeria, muscular dystrophy, and various cancers. Experiments...
Abnormalities in the shapes of mammalian cell nuclei are hallmarks of a variety of diseases, including progeria, muscular dystrophy, and various cancers. Experiments have shown that there is a causal relationship between chromatin organization and nuclear morphology. Decreases in heterochromatin levels, perturbations to heterochromatin organization, and increases in euchromatin levels all lead to misshapen nuclei, which exhibit deformations, such as nuclear blebs and nuclear ruptures. However, the polymer physical mechanisms of how chromatin governs nuclear shape and integrity are poorly understood. To investigate how heterochromatin and euchromatin, which are thought to microphase separate , govern nuclear morphology, we implemented a composite coarse-grained polymer and elastic shell model. By varying chromatin volume fraction (density), heterochromatin levels and structure, and heterochromatin-lamina interactions, we show how the spatial organization of chromatin polymer phases within the nucleus could perturb nuclear shape in some scenarios. Increasing the volume fraction of chromatin in the cell nucleus stabilizes the nuclear lamina against large fluctuations. However, surprisingly, we find that increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations in our simulations by a "wetting"-like interaction. In contrast, shape fluctuations are largely insensitive to the internal structure of the heterochromatin, such as the presence or absence of chromatin-chromatin crosslinks. Therefore, our simulations suggest that heterochromatin accumulation at the nuclear periphery could perturb nuclear morphology in a nucleus or nuclear region that is sufficiently soft, while stabilization of the nucleus via heterochromatin likely occurs through mechanisms other than chromatin microphase organization.
PubMed: 38168411
DOI: 10.1101/2023.12.16.571697 -
Remodeling of the Cardiac Extracellular Matrix Proteome During Chronological and Pathological Aging.Molecular & Cellular Proteomics : MCP Jan 2024Impaired extracellular matrix (ECM) remodeling is a hallmark of many chronic inflammatory disorders that can lead to cellular dysfunction, aging, and disease...
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. For this purpose, we first 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 and ECM-associated proteins quantified (named as Matrisome), we identified 13 proteins that were increased during aging, including lactadherin (MFGE8), collagen VI α6 (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, which may provide an additional layer to prevent cardiac aging.
Topics: Humans; Proteome; Endothelial Cells; Heart; Aging; Extracellular Matrix; Extracellular Matrix Proteins
PubMed: 38141925
DOI: 10.1016/j.mcpro.2023.100706 -
Aging Cell Feb 2024Several premature aging mouse models have been developed to study aging and identify interventions that can delay age-related diseases. Yet, it is still unclear whether...
Several premature aging mouse models have been developed to study aging and identify interventions that can delay age-related diseases. Yet, it is still unclear whether these models truly recapitulate natural aging. Here, we analyzed DNA methylation in multiple tissues of four previously reported mouse models of premature aging (Ercc1, LAKI, Polg, and Xpg). We estimated DNA methylation (DNAm) age of these samples using the Horvath clock. The most pronounced increase in DNAm age could be observed in Ercc1 mice, a strain which exhibits a deficit in DNA nucleotide excision repair. Similarly, we detected an increase in epigenetic age in fibroblasts isolated from patients with progeroid syndromes associated with mutations in DNA excision repair genes. These findings highlight that mouse models with deficiencies in DNA repair, unlike other premature aging models, display accelerated epigenetic age, suggesting a strong connection between DNA damage and epigenetic dysregulation during aging.
Topics: Humans; Mice; Animals; Aging, Premature; Aging; DNA Repair; DNA Methylation; Proteins; Epigenesis, Genetic; DNA
PubMed: 38140713
DOI: 10.1111/acel.14058 -
PeerJ 2023Aging is a natural and complex process characterized by the gradual deterioration of tissue and physiological functions in the organism over time. Cell senescence, a...
Aging is a natural and complex process characterized by the gradual deterioration of tissue and physiological functions in the organism over time. Cell senescence, a hallmark of aging, refers to the permanent and irreversible cell cycle arrest of proliferating cells triggered by endogenous stimuli or environmental stresses. Eliminating senescent cells has been shown to extend the healthy lifespan. In this study, we established a progeria mouse model with telomerase deficiency and confirmed the presence of shortened telomere length and increased expression of aging markers and in the organ tissues of G3 mice. We identified fisetin as a potent senolytic drug capable of reversing premature aging signs in telomerase-deficient mice. Fisetin treatment effectively suppressed the upregulation of aging markers and and reduced collagen fiber deposition. Furthermore, we observed a significant elevation in the mRNA level of in G3 mice, which was reduced after fisetin treatment. Stc1 has been implicated in anti-apoptotic processes through the upregulation of the Akt signaling pathway. Our findings reveal that fisetin exerts its anti-aging effect by inhibiting the Akt signaling pathway through the suppression of expression, leading to the apoptosis of senescent cells.
Topics: Animals; Mice; Telomerase; Cyclin-Dependent Kinase Inhibitor p16; Progeria; Proto-Oncogene Proteins c-akt; Telomere Shortening; Telomere; Aging
PubMed: 38107570
DOI: 10.7717/peerj.16463 -
The Journal of Cell Biology Jan 2024Mutations in genes encoding nuclear lamins cause diseases called laminopathies. In this issue, Hasper et al. (https://doi.org/10.1083/jcb.202307049) show that lamin A/C...
Mutations in genes encoding nuclear lamins cause diseases called laminopathies. In this issue, Hasper et al. (https://doi.org/10.1083/jcb.202307049) show that lamin A/C and the prelamin A variant in Hutchinson-Gilford progeria syndrome have relatively long lifetimes in affected tissues.
Topics: Humans; Lamins; Lamin Type A; Nuclear Lamina; Progeria
PubMed: 38078930
DOI: 10.1083/jcb.202311193 -
Nucleus (Austin, Tex.) Dec 2023Several related progeroid disorders are caused by defective post-translational processing of prelamin A, the precursor of the nuclear scaffold protein lamin A, encoded...
Several related progeroid disorders are caused by defective post-translational processing of prelamin A, the precursor of the nuclear scaffold protein lamin A, encoded by . Prelamin A undergoes farnesylation and additional modifications at its C-terminus. Subsequently, the farnesylated C-terminal segment is cleaved off by the zinc metalloprotease ZMPSTE24. The premature aging disorder Hutchinson Gilford progeria syndrome (HGPS) and a related progeroid disease, mandibuloacral dysplasia (MAD-B), are caused by mutations in and , respectively, that result in failure to process the lamin A precursor and accumulate permanently farnesylated forms of prelamin A. The farnesyl transferase inhibitor (FTI) lonafarnib is known to correct the aberrant nuclear morphology of HGPS patient cells and improves lifespan in children with HGPS. Importantly, and in contrast to a previous report, we show here that FTI treatment also improves the aberrant nuclear phenotypes in MAD-B patient cells with mutations in (P248L or L425P). As expected, lonafarnib does not correct nuclear defects for cells with lamin A processing-proficient mutations. We also examine prelamin A processing in fibroblasts from two individuals with a prevalent laminopathy mutation -R644C. Despite the proximity of residue R644 to the prelamin A cleavage site, neither R644C patient cell line shows a prelamin A processing defect, and both have normal nuclear morphology. This work clarifies the prelamin A processing status and role of FTIs in a variety of laminopathy patient cells and supports the FDA-approved indication for the FTI Zokinvy for patients with processing-deficient progeroid laminopathies, but not for patients with processing-proficient laminopathies.
Topics: Child; Humans; Lamin Type A; Progeria; Enzyme Inhibitors; Mutation; Lipodystrophy; Fibroblasts; Transferases; Metalloendopeptidases; Membrane Proteins
PubMed: 38050983
DOI: 10.1080/19491034.2023.2288476 -
Aging Cell Dec 2023The NAD -dependent deacylase family of sirtuin enzymes have been implicated in biological ageing, late-life health and overall lifespan, though of these members, a role...
The NAD -dependent deacylase family of sirtuin enzymes have been implicated in biological ageing, late-life health and overall lifespan, though of these members, a role for sirtuin-2 (SIRT2) is less clear. Transgenic overexpression of SIRT2 in the BubR1 hypomorph model of progeria can rescue many aspects of health and increase overall lifespan, due to a specific interaction between SIRT2 and BubR1 that improves the stability of this protein. It is less clear whether SIRT2 is relevant to biological ageing outside of a model where BubR1 is under-expressed. Here, we sought to test whether SIRT2 over-expression would impact the overall health and lifespan of mice on a nonprogeroid, wild-type background. While we previously found that SIRT2 transgenic overexpression prolonged female fertility, here, we did not observe any additional impact on health or lifespan, which was measured in both male and female mice on standard chow diets, and in males challenged with a high-fat diet. At the biochemical level, NMR studies revealed an increase in total levels of a number of metabolites in the brain of SIRT2-Tg animals, pointing to a potential impact in cell composition; however, this did not translate into functional differences. Overall, we conclude that strategies to enhance SIRT2 protein levels may not lead to increased longevity.
Topics: Animals; Female; Male; Mice; Aging; Animals, Genetically Modified; Brain; Longevity; Sirtuin 2
PubMed: 38009412
DOI: 10.1111/acel.14027 -
Journal of Developmental Biology Oct 2023The presence of farnesylated proteins at the inner nuclear membrane (INM), such as the Lamins or Kugelkern in , leads to specific changes in the nuclear morphology and...
The presence of farnesylated proteins at the inner nuclear membrane (INM), such as the Lamins or Kugelkern in , leads to specific changes in the nuclear morphology and accelerated ageing on the organismal level reminiscent of the Hutchinson-Gilford progeria syndrome (HGPS). Farnesyl transferase inhibitors (FTIs) can suppress the phenotypes of the nuclear morphology in cultured fibroblasts from HGPS patients and cultured cells overexpressing farnesylated INM proteins. Similarly, FTIs have been reported to suppress the shortened lifespan in model organisms. Here, we report an experimental system combining cell culture and flies for testing the activity of substances on the HGPS-like nuclear morphology and lifespan, with FTIs as an experimental example. Consistent with previous reports, we show that FTIs were able to ameliorate the nuclear phenotypes induced by the farnesylated nuclear proteins Progerin, Kugelkern, or truncated Lamin B in cultured cells. The subsequent validation in lifespan assays demonstrated the applicability of the experimental system: treating adult with the FTI ABT-100 reversed the nuclear phenotypes and extended the lifespan of experimentally induced short-lived flies. Since -expressing flies have a significantly shorter average lifespan, half the time is needed for testing substances in the lifespan assay.
PubMed: 37987370
DOI: 10.3390/jdb11040040 -
Bioorganic Chemistry Jan 2024Hutchinson-Gilford progeria syndrome (HGPS) or progeria is a rare genetic disease that causes premature aging, leading to a drastic reduction in the life expectancy of...
Hutchinson-Gilford progeria syndrome (HGPS) or progeria is a rare genetic disease that causes premature aging, leading to a drastic reduction in the life expectancy of patients. Progeria is mainly caused by the intracellular accumulation of a defective protein called progerin, generated from a mutation in the LMNA gene. Currently, there is only one approved drug for the treatment of progeria, which has limited efficacy. It is believed that progerin levels are the most important biomarker related to the severity of the disease. However, there is a lack of effective tools to directly visualize progerin in the native cellular models, since the commercially available antibodies are not well suited for the direct visualization of progerin in cells from the mouse model of the disease. In this context, an alternative option for the visualization of a protein relies on the use of fluorescent chemical probes, molecules with affinity and specificity towards a protein. In this work we report the synthesis and characterization of a new fluorescent probe (UCM-23079) that allows for the direct visualization of progerin in cells from the most widely used progeroid mouse model. Thus, UCM-23079 is a new tool compound that could help prioritize potential preclinical therapies towards the final goal of finding a definitive cure for progeria.
Topics: Mice; Animals; Humans; Progeria; Fluorescent Dyes; Mutation
PubMed: 37979321
DOI: 10.1016/j.bioorg.2023.106967