scholarly journals Loss of Aklotho Causes Reduced Motor Ability and Short Lifespan in Zebrafish

2020 ◽  
Author(s):  
Yurie Ogura ◽  
Kota Ujibe ◽  
Yuma Wakamatsu ◽  
Hiromi Hirata
Keyword(s):  
Life Span ◽  
Swimming Performance ◽  
Transmembrane Protein ◽  
Growth Factor Receptor ◽  
Accelerated Aging ◽  
Premature Death ◽  
Premature Aging ◽  
Motor Ability ◽  
Physiological Basis ◽  
Spontaneous Movements

Abstract The klotho gene encodes a transmembrane protein aKlotho that interacts with a fibroblast growth factor receptor in renal tubular epithelial cells and functions as a co-receptor for FGF23, which is an osteocytes-derived hormone. It is known that this bone-to-kidney signal promotes urinary phosphate excretion. Interestingly, aKlotho-deficient mice show accelerated aging and shortened life span in addition to dysregulation of serum phosphorus. However, physiological basis of aging-related function of aklotho and its generality in animals remain unclear. The aklotho-deficient vertebrate animals other than mice have been awaited as an alternative premature aging model. We here employed zebrafish in our aklotho study and revealed that aklotho mutant zebrafish appear to be normal at 3 months postfertilization (mpf) in young adults but eventually undergo premature death by 9 mpf, while normal zebrafish is known to survive for 42 months. We also assessed motor ability of zebrafish in a forced swimming assay and found that aklotho mutant zebrafish displayed reduced swimming performance before their survival declined. A recent study also reported a similar finding that aklotho-deficient zebrafish exhibited short life span and reduced spontaneous movements. Taken together, these results suggest that aKlotho mutant zebrafish show premature aging and are useful to investigate aging in vertebrates.

scholarly journals Loss of αklotho causes reduced motor ability and short lifespan in zebrafish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yurie Ogura ◽  
Ryoji Kaneko ◽  
Kota Ujibe ◽  
Yuma Wakamatsu ◽  
Hiromi Hirata
Keyword(s):  
Life Span ◽  
Swimming Performance ◽  
Transmembrane Protein ◽  
Premature Death ◽  
Premature Aging ◽  
Motor Ability ◽  
Short Life ◽  
Physiological Basis ◽  
Short Life Span ◽  
Spontaneous Movements

AbstractThe klotho gene encodes a transmembrane protein αKlotho that interacts with a fibroblast growth factor (FGF) receptor in renal tubular epithelial cells and functions as a co-receptor for FGF23, which is an osteocytes-derived hormone. This bone-to-kidney signal promotes urinary phosphate excretion. Interestingly, αKlotho knockout mice show an accelerated aging and a shortened life span. Similarly, C. elegans lacking the αklotho homologue showed a short life span. However, the physiological basis of aging-related function of αklotho remain unclear. The αklotho-deficient vertebrate animals other than mice have been awaited as an alternative model of premature aging. We here employed zebrafish in our study and revealed that αklotho mutant zebrafish appeared to be normal at 3 months postfertilization (mpf) but eventually underwent premature death by 9 mpf, while normal zebrafish is known to survive for 42 months. We also assessed the motor ability of zebrafish in a forced swimming assay and found that αklotho mutant zebrafish displayed reduced swimming performance before their survival declined. A recent study also reported a similar finding that αklotho-deficient zebrafish exhibited a short life span and reduced spontaneous movements. Taken together, these results suggest that αKlotho mutant zebrafish show premature aging and are useful to investigate aging in vertebrates.

scholarly journals The Short Life Span of Saccharomyces cerevisiae sgs1 and srs2 Mutants Is a Composite of Normal Aging Processes and Mitotic Arrest Due to Defective Recombination

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1531-1542 ◽  
Author(s):  
Mitch McVey ◽  
Matt Kaeberlein ◽  
Heidi A Tissenbaum ◽  
Leonard Guarente
Keyword(s):  
Cell Cycle ◽  
Life Span ◽  
Mitotic Cell ◽  
Dna Helicase ◽  
Premature Aging ◽  
Growth Defect ◽  
Short Life Span ◽  
Single Strand Annealing ◽  
Late Generation ◽  
Strand Annealing

Abstract Evidence from many organisms indicates that the conserved RecQ helicases function in the maintenance of genomic stability. Mutation of SGS1 and WRN, which encode RecQ homologues in budding yeast and humans, respectively, results in phenotypes characteristic of premature aging. Mutation of SRS2, another DNA helicase, causes synthetic slow growth in an sgs1 background. In this work, we demonstrate that srs2 mutants have a shortened life span similar to sgs1 mutants. Further dissection of the sgs1 and srs2 survival curves reveals two distinct phenomena. A majority of sgs1 and srs2 cells stops dividing stochastically as large-budded cells. This mitotic cell cycle arrest is age independent and requires the RAD9-dependent DNA damage checkpoint. Late-generation sgs1 and srs2 cells senesce due to apparent premature aging, most likely involving the accumulation of extrachromosomal rDNA circles. Double sgs1 srs2 mutants are viable but have a high stochastic rate of terminal G2/M arrest. This arrest can be suppressed by mutations in RAD51, RAD52, and RAD57, suggesting that the cell cycle defect in sgs1 srs2 mutants results from inappropriate homologous recombination. Finally, mutation of RAD1 or RAD50 exacerbates the growth defect of sgs1 srs2 cells, indicating that sgs1 srs2 mutants may utilize single-strand annealing as an alternative repair pathway.

scholarly journals Human WRN is an intrinsic inhibitor of progerin, abnormal splicing product of lamin A

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
So-mi Kang ◽  
Min-Ho Yoon ◽  
Su-Jin Lee ◽  
Jinsook Ahn ◽  
Sang Ah Yi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Life Span ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Werner Syndrome ◽  
Genetic Disorder ◽  
Dna Helicase ◽  
Premature Aging ◽  
Lamin A ◽  
Short Life Span

AbstractWerner syndrome (WRN) is a rare progressive genetic disorder, caused by functional defects in WRN protein and RecQ4L DNA helicase. Acceleration of the aging process is initiated at puberty and the expected life span is approximately the late 50 s. However, a Wrn-deficient mouse model does not show premature aging phenotypes or a short life span, implying that aging processes differ greatly between humans and mice. Gene expression analysis of WRN cells reveals very similar results to gene expression analysis of Hutchinson Gilford progeria syndrome (HGPS) cells, suggesting that these human progeroid syndromes share a common pathological mechanism. Here we show that WRN cells also express progerin, an abnormal variant of the lamin A protein. In addition, we reveal that duplicated sequences of human WRN (hWRN) from exon 9 to exon 10, which differ from the sequence of mouse WRN (mWRN), are a natural inhibitor of progerin. Overexpression of hWRN reduced progerin expression and aging features in HGPS cells. Furthermore, the elimination of progerin by siRNA or a progerin-inhibitor (SLC-D011 also called progerinin) can ameliorate senescence phenotypes in WRN fibroblasts and cardiomyocytes, derived from WRN-iPSCs. These results suggest that progerin, which easily accumulates under WRN-deficient conditions, can lead to premature aging in WRN and that this effect can be prevented by SLC-D011.

Accelerated aging and mortality in long-term survivors of childhood cancer: A report from the St. Jude Lifetime Cohort (SJLIFE).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 10045-10045
Author(s):  
AnnaLynn M. Williams ◽  
Jeanne S. Mandelblatt ◽  
Mingjuan Wang ◽  
Kirsten K. Ness ◽  
Gregory T. Armstrong ◽  
...  
Keyword(s):  
Childhood Cancer ◽  
Proportional Hazards ◽  
Accelerated Aging ◽  
Cox Proportional Hazards ◽  
Premature Aging ◽  
Self Report ◽  
Deficit Accumulation ◽  
Risk Of Death ◽  
Increased Risk ◽  
Survivors Of Childhood Cancer

10045 Background: Survivors of childhood cancer have functional limitations and health-related morbidity consistent with an accelerated aging phenotype. We characterized aging using a Deficit Accumulation Index (DAI) which examines the accumulation of multiple aging-related deficits readily available from medical records and self-report. DAI’s are used as surrogates of biologic aging and are validated to predict mortality in adult cancer patients. Methods: We included childhood cancer survivors (N = 3,758, mean age 30 [SD 8], 22 [9] years post diagnosis, 52% male) and community controls (N = 575, mean age 34 [10] 44% male) who completed clinical assessments and questionnaires and who were followed for mortality through December 31st, 2018 (mean follow-up 6.1 [3.1] years). Using the initial SJLIFE clinical assessment, a DAI score was generated as the proportion of deficits out of 44 items related to aging, including chronic conditions (e.g. hearing loss, hypertension), psychosocial and physical function, and activities of daily living. The total score ranged 0 to 1; scores > 0.20 are robust, while moderate and large clinically meaningful differences are 0.02 and 0.06, respectively. Linear regression compared the DAI in survivors and controls with an age*survivor/control interaction and examined treatment associations in survivors. Cox-proportional hazards models estimated risk of death associated with DAI. All models were adjusted for age, sex, and race. Results: Mean [SD] of DAI was 0.17 [0.11] for survivors and 0.10 [0.08] for controls. 32% of survivors had a DAI above the 90th percentile of the control distribution (p < 0.001). After adjustment for covariates, survivors had a statistically and clinically meaningfully higher DAI score than controls (β = 0.072 95%CI 0.062, 0.081; p < 0.001). When plotted against age, the adjusted DAI at the average age of survivors (30 years) was 0.166 (95% CI 0.160,0.171), which corresponded to 60 years of age in controls, suggesting premature aging of 30 years. The mean difference in DAI between survivors and controls increased with age from 0.06 (95% CI 0.04, 0.07) at age 20 to 0.11 (95% CI 0.08, 0.13) at age 60, consistent with an accelerated aging phenotype (p = 0.014). Cranial radiation, abdominal radiation, cyclophosphamide, platinum agents, neurosurgery, and amputation were each associated with a higher DAI (all p≤0.001). Among survivors, a 0.06 increase in DAI was associated with a 41% increased risk of all-cause mortality (HR 1.41 95%CI 1.32, 1.50; p < 0.001). Conclusions: Survivors of childhood cancer experience significant age acceleration that is associated with an increased risk of mortality; longitudinal analyses are underway to validate these findings. Given the ease of estimating a DAI, this may be a feasible method to quickly identify survivors for novel and tailored interventions that can improve health and prevent premature mortality.

scholarly journals Mutations in the WRN Gene in Mice Accelerate Mortality in a p53-Null Background

2000 ◽  
Vol 20 (9) ◽  
pp. 3286-3291 ◽  
Author(s):  
David B. Lombard ◽  
Caroline Beard ◽  
Brad Johnson ◽  
Robert A. Marciniak ◽  
Jessie Dausman ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Life Span ◽  
Human Disease ◽  
Dna Helicase ◽  
Premature Aging ◽  
Mutant Mice ◽  
Helicase Domain ◽  
C Terminus ◽  
Accelerated Senescence

ABSTRACT Werner's syndrome (WS) is a human disease with manifestations resembling premature aging. The gene defective in WS, WRN, encodes a DNA helicase. Here, we describe the generation of mice bearing a mutation that eliminates expression of the C terminus of the helicase domain of the WRN protein. Mutant mice are born at the expected Mendelian frequency and do not show any overt histological signs of accelerated senescence. These mice are capable of living beyond 2 years of age. Cells from these animals do not show elevated susceptibility to the genotoxins camptothecin or 4-NQO. However, mutant fibroblasts senesce approximately one passage earlier than controls. Importantly,WRN−/− ;p53−/− mice show an increased mortality rate relative toWRN+/− ;p53−/− animals. We consider possible models for the synergy betweenp53 and WRN mutations for the determination of life span.

T cells with dysfunctional mitochondria induce multimorbidity and premature senescence

Science ◽  
2020 ◽  
Vol 368 (6497) ◽  
pp. 1371-1376 ◽  
Author(s):  
Gabriela Desdín-Micó ◽  
Gonzalo Soto-Heredero ◽  
Juan Francisco Aranda ◽  
Jorge Oller ◽  
Elisa Carrasco ◽  
...  
Keyword(s):  
T Cells ◽  
Nicotinamide Adenine Dinucleotide ◽  
Premature Death ◽  
Premature Aging ◽  
Associated Diseases ◽  
Mitochondrial Transcription Factor ◽  
Mitochondrial Transcription Factor A ◽  
Factor Α ◽  
Organismal Fitness ◽  
Necrosis Factor

The effect of immunometabolism on age-associated diseases remains uncertain. In this work, we show that T cells with dysfunctional mitochondria owing to mitochondrial transcription factor A (TFAM) deficiency act as accelerators of senescence. In mice, these cells instigate multiple aging-related features, including metabolic, cognitive, physical, and cardiovascular alterations, which together result in premature death. T cell metabolic failure induces the accumulation of circulating cytokines, which resembles the chronic inflammation that is characteristic of aging (“inflammaging”). This cytokine storm itself acts as a systemic inducer of senescence. Blocking tumor necrosis factor–α signaling or preventing senescence with nicotinamide adenine dinucleotide precursors partially rescues premature aging in mice with Tfam-deficient T cells. Thus, T cells can regulate organismal fitness and life span, which highlights the importance of tight immunometabolic control in both aging and the onset of age-associated diseases.

Downregulation of Klotho expression by dehydration

2011 ◽  
Vol 301 (4) ◽  
pp. F745-F750 ◽  
Author(s):  
Cai Tang ◽  
Ganesh Pathare ◽  
Diana Michael ◽  
Abul Fajol ◽  
Melanie Eichenmüller ◽  
...  
Keyword(s):  
Transmembrane Protein ◽  
Accelerated Aging ◽  
Early Death ◽  
Renal Tissue ◽  
Hek293 Cells ◽  
Protein Abundance ◽  
Transcript Levels ◽  
Age Related ◽  
Klotho Protein ◽  
Growth Deficit

Klotho, a transmembrane protein, protease, and hormone mainly expressed in renal tissue counteracts aging. Overexpression of Klotho substantially prolongs the life span. Klotho deficiency leads to excessive formation of 1,25(OH)2D3, growth deficit, accelerated aging, and early death. Aging is frequently paralleled by dehydration, which is considered to accelerate the development of age-related disorders. The present study explored the possibility that dehydration influences Klotho expression. Klotho transcript levels were determined by RT-PCR, and Klotho protein abundance was detected by Western blotting in renal tissue from hydrated and 36-h-dehydrated mice as well as in human embryonic kidney (HEK293) cells. Dehydration was followed by a significant decline of renal Klotho transcript levels and protein abundance, accompanied by an increase in plasma osmolarity as well as plasma ADH, aldosterone, and 1,25(OH)2D3 levels. Antidiuretic hormone (ADH; 50 nM) and aldosterone (1 μM) significantly decreased Klotho transcription and protein expression in HEK293 cells. In conclusion, the present observations disclose a powerful effect of dehydration on Klotho expression, an effect at least partially mediated by enhanced release of ADH and aldosterone.

scholarly journals Hyperadiponectinemia protects against premature death in metabolic syndrome model mice by inhibiting AKT signaling and chronic inflammation

2012 ◽  
Vol 213 (1) ◽  
pp. 67-76 ◽  
Author(s):  
S Otabe ◽  
N Wada ◽  
T Hashinaga ◽  
X Yuan ◽  
I Shimokawa ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Accelerated Aging ◽  
Premature Death ◽  
Akt Signaling ◽  
Gene Expressions ◽  
Glucose Levels ◽  
Reactive Protein ◽  
The Metabolic Syndrome ◽  
Daily Food ◽  
Phosphorylated Akt

We previously reported that transgenic (Tg) expression of adiponectin significantly prolonged the lifespan of normal mice. The aim of this study was to elucidate the mechanism involved in the longevity effects of adiponectin using KK/Ta mice, a murine model of metabolic syndrome. We established a Tg line of KK/Ta (Tg-KK/Ta) mice expressing human adiponectin in the liver, and assessed their lifespan. The cause of death was determined by macroscopic and microscopic examinations immediately after death. The expressions of SIRT1, C-reactive protein (CRP), inflammatory cytokines, AMPK, and AKT were measured by quantitative real-time PCR, ELISAs, and/or western blotting. KK/Ta mice had lower serum adiponectin levels and shorter lifespan (57.6±13.9 vs 106.5±18.3 weeks, P<0.0001) than C57BL/6N mice. Tg adiponectin expression significantly extended the lifespan of KK/Ta mice (73.6±16.6 weeks, P<0.001) without affecting body weight, daily food consumption, or plasma glucose levels. Neoplasms were observed in only three of 22 KK/Ta mice that died spontaneously because of tumors. Atherosclerotic lesions were not detected in any mice. SIRT1 levels were not significantly different between KK/Ta and Tg-KK/Ta mice. Gene expressions of Crp, Tnfα, Il6, and Nfκb were increased in KK/Ta mice, but they were significantly attenuated in Tg-KK/Ta mice. Phosphorylated AMPK levels were increased and phosphorylated AKT levels were decreased in Tg-KK/Ta mice. The anti-inflammatory effects of adiponectin, achieved by inhibiting the AKT signaling pathway, may explain how adiponectin slows the accelerated aging process associated with the metabolic syndrome.

scholarly journals Two Copies of mthmg1, Encoding a Novel Mitochondrial HMG-Like Protein, Delay Accumulation of Mitochondrial DNA Deletions in Podospora anserina

2002 ◽  
Vol 1 (4) ◽  
pp. 503-513 ◽  
Author(s):  
Michelle Dequard-Chablat ◽  
Cynthia Alland
Keyword(s):  
Mitochondrial Dna ◽  
Dna Binding ◽  
Mitochondrial Genome ◽  
Life Span ◽  
Cellular Localization ◽  
Premature Death ◽  
Podospora Anserina ◽  
Protein Fusion ◽  
Dna Binding Domains ◽  
Binding Domains

ABSTRACT In the filamentous fungus Podospora anserina, two degenerative processes which result in growth arrest are associated with mitochondrial genome (mitochondrial DNA [mtDNA]) instability. Senescence is correlated with mtDNA rearrangements and amplification of specific regions (senDNAs). Premature death syndrome is characterized by the accumulation of specific mtDNA deletions. This accumulation is due to indirect effects of the AS1-4 mutation, which alters a cytosolic ribosomal protein gene. The mthmg1 gene has been identified as a double-copy suppressor of premature death. It greatly delays premature death and the accumulation of deletions when it is present in two copies in an AS1-4 context. The duplication of mthmg1 has no significant effect on the wild-type life span or on senDNA patterns. In an AS1 + context, deletion of the mthmg1 gene alters germination, growth, and fertility and reduces the life span. The Δmthmg1 senescent strains display a particular senDNA pattern. This deletion is lethal in an AS1-4 context. According to its physical properties (very basic protein with putative mitochondrial targeting sequence and HMG-type DNA-binding domains) and the cellular localization of an mtHMG1-green fluorescent protein fusion, mtHMG1 appears to be a mitochondrial protein possibly associated with mtDNA. It is noteworthy that it is the first example of a protein combining the two DNA-binding domains, AT-hook motif and HMG-1 boxes. It may be involved in the stability and/or transmission of the mitochondrial genome. To date, no structural homologues have been found in other organisms. However, mtHMG1 displays functional similarities with the Saccharomyces cerevisiae mitochondrial HMG-box protein Abf2.

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