Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Sep 23;10(1):15513.
doi: 10.1038/s41598-020-72637-9.

SUMO promotes longevity and maintains mitochondrial homeostasis during ageing in Caenorhabditis elegans

Andrea Princz  1   2 , Federico Pelisch  3 , Nektarios Tavernarakis  4   5
Affiliations

SUMO promotes longevity and maintains mitochondrial homeostasis during ageing in Caenorhabditis elegans

Andrea Princz et al. Sci Rep. .

Abstract

The insulin/IGF signalling pathway impacts lifespan across distant taxa, by controlling the activity of nodal transcription factors. In the nematode Caenorhabditis elegans, the transcription regulators DAF-16/FOXO and SKN-1/Nrf function to promote longevity under conditions of low insulin/IGF signalling and stress. The activity and subcellular localization of both DAF-16 and SKN-1 is further modulated by specific posttranslational modifications, such as phosphorylation and ubiquitination. Here, we show that ageing elicits a marked increase of SUMO levels in C. elegans. In turn, SUMO fine-tunes DAF-16 and SKN-1 activity in specific C. elegans somatic tissues, to enhance stress resistance. SUMOylation of DAF-16 modulates mitochondrial homeostasis by interfering with mitochondrial dynamics and mitophagy. Our findings reveal that SUMO is an important determinant of lifespan, and provide novel insight, relevant to the complexity of the signalling mechanisms that influence gene expression to govern organismal survival in metazoans.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
SUMO levels are increasing during ageing. (A) Western blot analysis of SUMO protein levels in day 1, 4 and 8 wild type lysates (n = 500 worms/sample, N = 4, day 1 vs day 4: p = 0.103, day 1 vs day 8: p = 0.119). Protein levels were normalized to α-tubulin. Error bars, S.E.M. (B) psmo-1DsRed::SMO-1 expression pattern, scale bar: 40 μm. The image was acquired using a × 20 objective lens. (C) The expression of psmo-1DsRed::SMO-1 is increasing during ageing and when the animals are grown at 25 °C. (n = 50, *p < 0.05, **p < 0.01, ***p < 0.001, unpaired t-test). Error bars, S.E.M.
Figure 2
Figure 2
SUMO modulates lifespan through the intestine and nervous system. (A, B) Knockdown of smo-1 shortens the lifespan of wild type animals, while overexpression of smo-1 extends lifespan. (C) Intestine specific smo-1(RNAi) shortens lifespan. (D) Neuron specific smo-1(RNAi) reduces lifespan. (E) Intestine specific smo-1 overexpression extends lifespan. (F) Neuron specific smo-1 overexpression does not have a significant effect on lifespan. Lifespan assays were carried out at 20 °C. Lifespan values are given in Table S1.
Figure 3
Figure 3
SKN-1 mediates the lifespan influencing effect of SUMO. (A) smo-1(RNAi) does not further reduce the short lifespan of skn-1(RNAi) treated animals. (B) skn-1(RNAi) shortens the lifespan of the FGP14 strain to the level seen in wild type animals subjected to skn-1 RNAi. (C) SMO-1 overexpressing animals survive longer on 2 mM paraquat, while loss of smo-1 does not change the survival compared to wild type animals. skn-1(RNAi) treated animals have a reduced survival rate on paraquat. (D) Heat shock did not change the survival of smo-1(RNAi) fed animals while worms overexpressing SMO-1 displayed increased survival rates. The percentage of animals remaining alive is plotted against age. (E) FGP14 animals are mounting a stronger oxidative stress response in day 2 animals compared to control, measured by pgst-4GFP expression. smo-1(RNAi) reduced the responsiveness of animals to paraquat. (n = 40, ***p < 0.001, **p < 0.01 unpaired t-test). Error bars, S.E.M. Lifespan assays were carried out at 20 °C. Lifespan values are given in Table S1.
Figure 4
Figure 4
DAF-16 is SUMO modified and SUMO inhibits the transcriptional activity of DAF-16. (A) smo-1(RNAi) shortens the lifespan of daf-16(mu86) animals. (B) The long lifespan of daf-2(e1370) animals is reduced by smo-1(RNAi) and extended by ulp-1(RNAi). (C) daf-16(RNAi) partly shortens the long lifespan of FGP14 strain. (D) ife-2(ok306) animals treated with ulp-1 RNAi have a longer lifespan. (E) In vitro DAF-16 SUMOylation assay. Top image shows Coomassie staining, bottom image shows fluorescently labelled SUMO with Alexa-Fluor 680. Brackets indicate the SUMO modified form of DAF-16. (F) Nuclear localization of pdaf-16DAF-16::GFP in control, smo-1(RNAi) and smo-1 overexpressing background (FGP14), daf-2(RNAi) was used as a positive control, scale bar: 50 μm. Images were acquired using × 40 objective lens (n = 50, ***p < 0.001, unpaired t-test). (G) pges-1mtGFP expression is elevated upon smo-1(RNAi) in wild type, daf-2(RNAi) and skn-1(RNAi) background in day 4 animals (n = 100, **p < 0.01, ***p < 0.001, unpaired t-test). (H) psod-3GFP is increased upon knockdown of smo-1, skn-1 or daf-2. Overexpression of smo-1 reduces the expression level of psod-3GFP in day 4 animals (n = 100, *p < 0.05, ***p < 0.001, unpaired t-test). (I, J). The mRNA levels of sod-3 and ges-1 are reduced in day 4 animals in the smo-1 overexpressing strain (***p < 0.001, unpaired t-test). Error bars, S.E.M. Lifespan assays were carried out at 20 °C. Lifespan values are given in Table S1.
Figure 5
Figure 5
SUMO changes the mitochondrial homeostasis. (A, B) TMRE staining declines during ageing in wild type but not smo-1(RNAi) treated animals, and this change is DAF-16 dependent (n = 100, *p < 0.05, **p < 0.01, ***p < 0.001, unpaired t-test). (C, D) Mitochondrial ROS production, measured by MitoTracker ROS, is increased when we knockdown smo-1 and this effect is also DAF-16 dependent (n = 75, *p < 0.05, **p < 0.01, ***p < 0.001, unpaired t-test). (E) H2O2 levels are increased in smo-1(RNAi) background, measured by the H2O2 biosensor, HyPer (n = 30, **p < 0.01, unpaired t-test). (F) ATP production is increased upon knockdown of smo-1 in day 6 wild type animals (*p < 0.05, ***p < 0.001, unpaired t-test). Error bars, S.E.M.
Figure 6
Figure 6
SUMO is required for efficient mitochondrial fission and regulates mitophagy. (A) The intestinal mitochondrial network becomes fragmented in day 8 wild type animals, but remains interconnected in smo-1(RNAi) treated animals, and the mitochondrial network influencing effect of SMO-1 is DAF-16 and EAT-3 dependent, scale bar: 10 μm. Images were acquired using × 63 objective lens (n = 40). (B) In the absence of drp-1 or fzo-1 the mitochondrial network undergoes fragmentation, and the loss of smo-1 rescues this phenotype (n = 15). (C) daf-2(RNAi) increases, while smo-1(RNAi) inhibits mitophagy in muscle cells (n = 40, **p < 0.01, ***p < 0.001, unpaired t-test). (D) Depletion of smo-1 induces neuronal mitophagy (n = 20, **p < 0.01, unpaired t-test). Error bars, S.E.M.
Figure 7
Figure 7
SUMOylation and ageing. Under normal conditions protein SUMOylation is balanced by conjugation and cleavage events. This ensures the tight control of mitochondrial function and dynamics, allowing for a normal lifespan. Depletion of SUMO leads to activation of stress responses, impairment of mitochondrial function and mitophagy, which shortens lifespan. SUMO modulates the activity of the DAF-16 and SKN-1, stress response transcription factors to influence ageing.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Lopez-Otin C, Blasco MA, Partridge L, Serrano M, Kroemer G. The hallmarks of aging. Cell. 2013;153:1194–1217. doi: 10.1016/j.cell.2013.05.039. - DOI - PMC - PubMed
    1. Ruan L, Zhang X, Li R. Recent insights into the cellular and molecular determinants of aging. J. Cell Sci. 2018 doi: 10.1242/jcs.210831. - DOI - PMC - PubMed
    1. Kenyon C, Chang J, Gensch E, Rudner A, Tabtiang R. A C. elegans mutant that lives twice as long as wild type. Nature. 1993;366:461–464. doi: 10.1038/366461a0. - DOI - PubMed
    1. Lin K, Dorman JB, Rodan A, Kenyon C. daf-16: An HNF-3/forkhead family member that can function to double the life-span of Caenorhabditis elegans. Science. 1997;278:1319–1322. doi: 10.1126/science.278.5341.1319. - DOI - PubMed
    1. Kenyon CJ. The genetics of ageing. Nature. 2010;464:504–512. doi: 10.1038/nature08980. - DOI - PubMed

Publication types

MeSH terms