scholarly journals Mitochondrial sirtuins sir-2.2 and sir-2.3 regulate lifespan in C. elegans

2017 ◽  
Author(s):  
Sarah M. Chang ◽  
Melanie R. McReynolds ◽  
Wendy Hanna-Rose
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Drug Targets ◽  
Physiological Role ◽  
Oxidative Stress Response ◽  
Altered Expression ◽  
C Elegans ◽  
Mitochondrial Superoxide ◽  
Age Related ◽  
Extended Lifespan

ABSTRACTMitochondrial sirtuins regulate biochemical pathways and are emerging drug targets for metabolic and age-related diseases such as cancer, diabetes, and neurodegeneration. Yet, their functions remain unclear. Here, we uncover a novel physiological role for the C. elegans mitochondrial sirtuins, sir-2.2 and sir-2.3, in lifespan regulation. Using a genetic approach, we demonstrate that sir-2.2 and sir-2.3 mutants live 28-30% longer than controls when fed the normal lab diet of E. coli OP50. Interestingly, this effect is diet specific and is not observed when animals are fed the strain HT115, which is typically used for RNAi experiments. While decreased consumption of food is a known mechanism for lifespan extension, this does not account for the increased lifespan in the mitochondrial sirtuin mutants. sir-2.2 and sir-2.3 mutants display altered expression of genes involved in oxidative stress response, including increased expression of the mitochondrial superoxide dismutase sod-3 and decreased levels of catalases ctl-1 and ctl-2. Like their extended lifespan phenotype, these alterations in oxidative stress gene expression are diet dependent. The mitochondrial sirtuin mutants are more resistant to the lifespan extending effects of low levels of superoxide, suggesting that their increased lifespan involves a hormetic response. Our data suggest that sir-2.2 and sir-2.3 are not completely redundant in function and may possess overlapping yet distinct mechanisms for regulating oxidative stress response and lifespan.

scholarly journals Virulence of Streptococcus pneumoniae: PsaA Mutants Are Hypersensitive to Oxidative Stress

2002 ◽  
Vol 70 (3) ◽  
pp. 1635-1639 ◽  
Author(s):  
Hsing-Ju Tseng ◽  
Alastair G. McEwan ◽  
James C. Paton ◽  
Michael P. Jennings
Keyword(s):  
Oxidative Stress ◽  
Streptococcus Pneumoniae ◽  
Stress Response ◽  
Nadh Oxidase ◽  
Redox Homeostasis ◽  
Oxidative Stress Response ◽  
Wild Type ◽  
Regulation Of Expression ◽  
Altered Expression ◽  
Transport Complex

ABSTRACT psaA encodes a 37-kDa pneumococcal lipoprotein which is part of an ABC Mn(II) transport complex. Streptococcus pneumoniae D39 psaA mutants have previously been shown to be significantly less virulent than wild-type D39, but the mechanism underlying the attenuation has not been resolved. In this study, we have shown that psaA and psaD mutants are highly sensitive to oxidative stress, i.e., to superoxide and hydrogen peroxide, which might explain why they are less virulent than the wild-type strain. Our investigations revealed altered expression of the key oxidative-stress response enzymes superoxide dismutase and NADH oxidase in psaA and psaD mutants, suggesting that PsaA and PsaD may play important roles in the regulation of expression of oxidative-stress response enzymes and intracellular redox homeostasis.

Multiple methionine sulfoxide reductase genes in Staphylococcus aureus: expression of activity and roles in tolerance of oxidative stress

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2739-2747 ◽  
Author(s):  
Vineet K. Singh ◽  
Jackob Moskovitz
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Stress Response ◽  
Double Mutant ◽  
Mutational Analysis ◽  
Physiological Role ◽  
Methionine Sulfoxide ◽  
Oxidative Stress Response ◽  
Methionine Sulfoxide Reductase ◽  
Activity Data

Staphylococcus aureus contains three genes encoding MsrA-specific methionine sulfoxide reductase (Msr) activity (msrA1, msrA2 and msrA3) and an additional gene that encodes MsrB-specific Msr activity. Data presented here suggest that MsrA1 is the major contributor of the MsrA activity in S. aureus. In mutational analysis, while the total Msr activity in msrA2 mutant was comparable to that of the parent, Msr activity was significantly up-regulated in the msrA1 or msrA1 msrA2 double mutant. Assessment of substrate specificity together with increased reactivity of the cell-free protein extracts of the msrA1 mutants to anti-MsrB polyclonal antibodies in Western analysis provided evidence that increased Msr activity was due to elevated synthesis of MsrB in the MsrA1 mutants. Previously, it was reported that oxacillin treatment of S. aureus cells led to induced synthesis of MsrA1 and a mutation in msrA1 increased the susceptibility of the organism to H2O2. A mutation in the msrA2 gene, however, was not significant for the bacterial oxidative stress response. In complementation assays, while the msrA2 gene was unable to complement the msrA1 msrA2 double mutant for H2O2 resistance, the same gene restored H2O2 tolerance in the double mutant when placed under the control of the msrA1 promoter. However, msrA1 which was able to complement the oxidative stress response in msrA1 mutants could not restore the tolerance of the msrA1 msrA2 mutants to H2O2 when placed under the control of the msrA2 promoter. Additionally, although the oxacillin minimum inhibitory concentration of the msrA1 mutant was comparable to that of the wild-type parent, in shaking liquid culture, the msrA1 mutant responded more efficiently to sublethal doses of oxacillin. The data suggest complex regulation of Msr proteins and a more significant physiological role for msrA1/msrB in S. aureus.

scholarly journals Antagonistic effects of chemical mixtures on the oxidative stress response are silenced by heat stress and reversed under dietary restriction

Exposome ◽  
2021 ◽  
Author(s):  
Karthik Suresh Arulalan ◽  
Javier Huayta ◽  
Jonathan W Stallrich ◽  
Adriana San-Miguel
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Design Of Experiments ◽  
Stress Responses ◽  
Current Knowledge ◽  
Oxidative Stress Response ◽  
Chemical Mixtures ◽  
C Elegans ◽  
Chemical Agents ◽  
Limited Food

Abstract Chemical agents released into the environment can induce oxidative stress in organisms, which is detrimental for health. Although environmental exposures typically include multiple chemicals, organismal studies on oxidative stress derived from chemical agents commonly study exposures to individual compounds. In this work, we explore how chemical mixtures drive the oxidative stress response under various conditions in the nematode C. elegans, by quantitatively assessing levels of gst-4 expression. Our results indicate that naphthoquinone mixtures drive responses differently than individual components, and that altering environmental conditions, such as increased heat and reduced food availability, result in dramatically different oxidative stress responses mounted by C. elegans. When exposed to heat, the oxidative stress response is diminished. Notably, when exposed to limited food, the oxidative stress response specific to juglone is significantly heightened, while identified antagonistic interactions between some naphthoquinone components in mixtures are abolished. This implies that organismal responses to xenobiotics is confounded by environment and stressor interactions. Given the high number of variables under study, and their potential combinations, a simplex centroid design was used to capture such non-trivial response over the design space. This makes the case for the adoption of Design of Experiments approaches as they can greatly expand the experimental space probed in noisy biological readouts, and in combinatorial experiments. Our results also reveal gaps in our current knowledge of the organismal oxidative stress response, which can be addressed by employing sophisticated design of experiments approaches to identify significant interactions.

scholarly journals Kynurenine Metabolism Lifespan Extension Mediated by Oxidative Stress Response and Hypoxic Response in C. elegans

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 684-684
Author(s):  
Raul Castro-Portuguez ◽  
Jeremy Meyers ◽  
Sam Freitas ◽  
Hope Dang ◽  
Emily Turner ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factors ◽  
Stress Response ◽  
Aging Process ◽  
De Novo ◽  
Kynurenine Pathway ◽  
Oxidative Stress Response ◽  
Lifespan Extension ◽  
Hypoxic Stress ◽  
C Elegans

Abstract Aging is characterized by a progressive decline in the normal physiological functions of an organism, ultimately leading to mortality. Metabolic changes throughout the aging process disrupt the balance and homeostasis of the cell. The kynurenine metabolic pathway is the sole de novo biosynthetic pathway for producing NAD+ from ingested tryptophan. Altered kynurenine pathway activity is associated with both aging and a variety of age-associated diseases, and kynurenine-based interventions can extend lifespan in Caenorhabditis elegans. Our laboratory recently demonstrated knockdown of the kynurenine pathway enzymes kynureninase (KYNU) or 3-hydroxyanthranilic acid dioxygenase (HAAO) increases lifespan by 20-30% in C elegans. However, the mechanism of how these interventions may modulate response against different stressors during the aging process has yet to be explored. Fluorescent reporter strains show the stress-responsive transcription factors skn-1 (ortholog of NRF2/NFE2L2; oxidative stress response) and hif-1 (ortholog of HIF1A; hypoxic stress response) to be highly upregulated when the kynurenine pathway is inhibited. We also demonstrated the increase expression of gst-4 and gcs-1 (transcriptional targets skn-1), which are involved in production of the antioxidant glutathione (GSH), as well as upregulation of cysl-2 (transcriptional target of hif-1), a regulator of cysteine biosynthesis from serine. We hypothesize that lifespan extension resulting from kynurenine pathway inhibition is mediated, at least in part, by upregulation of these transcription factors, providing elevated defense against oxidative stress and hypoxic stress.

scholarly journals 4-PHENYLBUTYRATE: MOLECULAR MECHANISMS AND AGING INTERVENTION POTENTIAL

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S101-S101
Author(s):  
Michael R Bene ◽  
Kevin Thyne ◽  
Jonathan Dorigatti ◽  
Adam B Salmon
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Molecular Mechanisms ◽  
Oxidative Stress Response ◽  
Chemical Chaperone ◽  
Mouse Muscle ◽  
Age Related ◽  
Primary Mouse ◽  
Wide Range

Abstract 4-Phenylbutyrate (PBA) is a FDA approved drug for treating patients with urea cycle disorders. Additionally, PBA acts upon several pathways thought of as important modifiers of aging including: histone deacetylation, proteostasis as a chemical chaperone, and stress resistance by regulating expression of oxidative stress response proteins. PBA has also been shown to extend lifespan and improve markers of age-related health in Drosophila. Due to its wide range of effects PBA has been investigated for use in numerous age-related disorders including neurodegenerative and cardiovascular diseases. To better understand the effects of PBA on the molecular level, we used both in cellulo and in vivo studies. Treatment of primary mouse fibroblasts, C2C12 mouse muscle cells, and NCTC 1469 mouse liver cells with PBA demonstrated differential responses among cell lines to upregulation of oxidative stress response and histone acetylation. Specifically, upregulation of the oxidative stress response protein DJ-1 by PBA was found to have a corresponding dose response curve to histone H3 acetylation in primary fibroblasts. To study effects of PBA in vivo, four cohorts of HET3 mice were treated with PBA at different doses in drinking water for 4 weeks. PBA was well tolerated and led to different effects on body composition dependent on the sex of mice. We are currently investigating the molecular effects of PBA treatment in multiple tissues samples from these mice. The potential of PBA to alter many fundamental pathways, and specifically those related to stress responses, make it an attractive prospect for treatment of many age-related disorders.

scholarly journals In vitro modeling of the complex retinal condition age-related macular degeneration

2022 ◽  
Author(s):  
Karolina Plössl ◽  
Emily Webster ◽  
Christina Kiel ◽  
Felix Grassmann ◽  
Caroline Brandl ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Macular Degeneration ◽  
Cell Lines ◽  
Genetic Risk ◽  
Oxidative Stress Response ◽  
Age Related Macular Degeneration ◽  
Nrf2 Pathway ◽  
Age Related

Aim: To model a complex retinal disease such as age-related macular degeneration (AMD) in vitro, we aimed to combine genetic and environmental risk factors in a retinal pigment epithelium (RPE) cell culture model generated via induced pluripotent stem cells (iPSCs) from subjects with an extremely high and an extremely low genetic disease risk. As an external stimulus, we chose defined oxidative stress conditions. Methods: Patients were genotyped for known AMD-associated genetic variants and their individual genetic risk score (GRS) was calculated defining individual iPSC-RPE cell lines which reflect the extreme ends of the genetic risk for AMD. Sodium iodate (NaIO3, SI) was used to induce oxidative stress and cellular responses were followed by analyzing nuclear factor erythroid 2-related factor 2 (NRF2) pathway activation by mRNA and protein expression. Results: We present a collection of eight iPSC-RPE cell lines, with four each harboring an extreme low or an extreme high GRS for AMD. RPE identity was verified structurally and functionally. We found that 24 and 72 h of SI treatment induced a significant upregulation of NRF2 response genes HMOX1 and NQO1, without showing cytotoxic effects or negatively influencing RPE cell integrity. High- vs. low-risk cell lines revealed similar first line defenses in oxidative stress response mediated through the NRF2 pathway. Conclusion: Delineating the NRF2-mediated oxidative stress response was sought in iPSC-RPE cell lines with maximally divergent genetic AMD risk profiles. Under the specific stress conditions chosen, our data indicate that genetic predisposition to AMD may not exert a major influence on the NRF2 signaling pathway.

Age-related differences in the oxidative stress response of primary rat hepatocytes

2013 ◽  
Vol 51 (01) ◽  
Author(s):  
B Burkhardt ◽  
N Kambeitz ◽  
O Matsarskaia ◽  
S Ehnert ◽  
U Müller-Vieira ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Rat Hepatocytes ◽  
Oxidative Stress Response ◽  
Primary Rat Hepatocytes ◽  
Age Related
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