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
[Preprint]. 2024 Mar 29:rs.3.rs-4087193.
doi: 10.21203/rs.3.rs-4087193/v1.

Oocyte mitochondria link maternal environment to offspring phenotype

Jason F Cooper  1 , Kim Nguyen  1 , Darrick Gates  1 , Emily Wolfrum  2 , Colt Capan  2 , Hyoungjoo Lee  2 , Devia Williams  1 , Chidozie Okoye  3 , Andrew P Wojtovich  3 , Nicholas O Burton  1
Affiliations

Oocyte mitochondria link maternal environment to offspring phenotype

Jason F Cooper et al. Res Sq. .

Abstract

During maturation oocytes undergo a recently discovered mitochondrial proteome remodeling event in flies1, frogs1, and humans2. This oocyte mitochondrial remodeling, which includes substantial changes in electron transport chain (ETC) subunit abundance1,2, is regulated by maternal insulin signaling1. Why oocytes undergo mitochondrial remodeling is unknown, with some speculating that it might be an evolutionarily conserved mechanism to protect oocytes from genotoxic damage by reactive oxygen species (ROS)2. In Caenorhabditis elegans, we previously found that maternal exposure to osmotic stress drives a 50-fold increase in offspring survival in response to future osmotic stress3. Like mitochondrial remodeling, we found that this intergenerational adaptation is also regulated by insulin signaling to oocytes3. Here, we used proteomics and genetic manipulations to show that insulin signaling to oocytes regulates offspring's ability to adapt to future stress via a mechanism that depends on ETC composition in maternal oocytes. Specifically, we found that maternally expressed mutant alleles of nduf-7 (complex I subunit) or isp-1 (complex III subunit) altered offspring's response to osmotic stress at hatching independently of offspring genotype. Furthermore, we found that expressing wild-type isp-1 in germ cells (oocytes) was sufficient to restore offspring's normal response to osmotic stress. Chemical mutagenesis screens revealed that maternal ETC composition regulates offspring's response to stress by altering AMP kinase function in offspring which in turn regulates both ATP and glycerol metabolism in response to continued osmotic stress. To our knowledge, these data are the first to show that proper oocyte ETC composition is required to link a mother's environment to adaptive changes in offspring metabolism. The data also raise the possibility that the reason diverse animals exhibit insulin regulated remodeling of oocyte mitochondria is to tailor offspring metabolism to best match the environment of their mother.

Keywords: AMP kinase; C. elegans; Intergenerational; aak-2; daf-2; gas-1; insulin; isp-1; mev-1; mitochondria; nduf-7; nuo-6; oocyte.

PubMed Disclaimer

Conflict of interest statement

Declarations of Interest: The authors declare that they have no competing interests.

Figures

Figure 1.
Figure 1.. Proper OxPhos function is required for C. elegans to intergenerationally adapt to osmotic stress.
(a) Volcano plot of 7,161 detected proteins in wild-type C. elegans embryos from parents exposed to either 50 mM (normal) or 300 mM NaCl (stressed) for 24 hours. Red dots are the 371 proteins that exhibit significant (padj < 0.01) changes in abundance relative to the 50 mM NaCl condition. (b) Cellular components with a significant (padj < 0.01) enrichment over expected in the offspring of parents exposed to 300 mM NaCl. Enrichments were determined with WormEnrichr,. (c) Percent of wild-type, nuo-6(qm200), nduf-7(et19), gas-1(fc21), mev-1(kn1), sdha-2(tm1420), isp-1(qm150), asg-2(tm1472), clk-1(qm30), fzo-1(tm1133), eat-3(ad426), and drp-1(tm1108) animals developing after 48 hours of exposure to 500 mM NaCl. Red dots represent offspring from parents grown under normal osmotic conditions (50 mM NaCl). Blue dots represent offspring from parents exposed to 300 mM NaCl for 24 hours. n = 3 replicates of > 40 offspring per replicate. Error bars – s.d. (d) Percent of wild-type, nuo-6(qm200), nduf-7(et19), gas-1(fc21), mev-1(kn1), and isp-1(qm150) mutants mobile and developing after 48 hours of exposure to 300 mM NaCl. n = 3 replicates of > 100 animals per replicate. Error bars – s.d. (e) Percent of wild-type, nuo-6(qm200), nduf-7(et19), gas-1(fc21), mev-1(kn1), and isp-1(qm150) mutants developing (compared to those that have entered a state of near suspended animation) after 48 hours of exposure to 350 mM NaCl. n = 3 replicates of > 100 animals per replicate. Error bars – s.d. (f) Percent of wild-type, nuo-6(qm200), nduf-7(et19), gas-1(fc21), mev-1(kn1), and isp-1(qm150) mutants mobile and developing after 48 hours of exposure to 350 mM NaCl. pGermline refers to animals that express a wild-type copy of isp-1 under the control of the pie-1 promoter. CRISPR-P225S represents a CRISPR re-creation of the qm150 allele – see methods. n = 3 replicates of > 100 animals per replicate. Error bars – s.d. *** p <0.001, **** p < 0.0001.
Figure 2.
Figure 2.. Proper maternal OxPhos composition is required to link maternal insulin signaling to oocytes to offspring response to osmotic stress at hatching.
(a) Percent of wild-type, daf-2(e1370), and isp-1(qm150) mutant animals developing and mobile after 48 hours of exposure to 500 mM NaCl. daf-2(e1370); isp-1(qm150)/+ animals harbor the nT1[qIs51] balancer to maintain heterozygous animals. Cross progeny from heterozygous parents were individually genotyped for each animal, and total animals for each cross are listed. Paternal genotype also contained him-8(e1489); otIs181 to generate male animals, and confirm cross progeny as previously described. The red box highlights genetically identical offspring that have different responses to osmotic stress. (b) Percent of wild-type, daf-2(e1370), and nduf-7(et19) mutant animals developing and mobile after 48 hours of exposure to 500 mM NaCl. Cross progeny from heterozygous parents were individually genotyped for each animal, and total animals for each cross are listed. Paternal genotype also contained him-8(e1489); otIs181 to generate male animals and confirm cross progeny, as previously described. The red box highlights genetically identical offspring that have different responses to osmotic stress. (c) Venn Diagram of proteins that change in abundance by proteomics profiling in nuo-6(qm200), nduf-7(et19), and isp-1(qm150) mutant embryos. See Supplementary Table 2 for complete list of individual proteins. (d) Relative abundance of NDUF-7 protein in nuo-6(qm200), nduf-7(et19), and isp-1(qm150) mutant embryos. n = 3 replicates. Error bars – s.d. (e) Relative abundance of NUO-6 protein in nuo-6(qm200), nduf-7(et19), and isp-1(qm150) mutant embryos. n = 3 replicates. Error bars – s.d. (f) Relative abundance of ISP-1 protein in nuo-6(qm200), nduf-7(et19), and isp-1(qm150) mutant embryos. n = 3 replicates. Error bars – s.d. * = p < 0.05, ** = p < 0.01, **** = p < 0.0001
Figure 3.
Figure 3.. ETC dysfunction regulates C. elegans response to osmotic stress via and AMP-kinase/aak-2 dependent mechanism.
(a) Representative images of >500 wild-type and aak-2 mutant C. elegans embryos placed on NGM agar plates containing 500 mM NaCl for 48 hours. 100% of wild-type animals enter suspended animation at hatching, while a fraction of aak-2 mutants bypass suspended animation and continue developing. For imaging purposes, plates contained no food and mobile animals remain in the L1 larval stage. Scale bars 1 mm. (b) Diagram of the aak-2 mutations recovered from mutagenesis screens. Red bar represents deletion region. (c) Percent of wild-type and aak-2 mutant animals developing and mobile after 48 hours of exposure to 500 mM NaCl. n = 3 replicates of >100 animals per replicate. Error bars – s.d. (d) Percent of wild-type, aak-2(n6251), and isp-1(qm150) mutants developing and mobile after 24 hours of exposure to 350 mM NaCl. n = 3 replicates of >100 animals per replicate. Error bars – s.d. (e) Number of wild-type and aak-2(n6251) mutant cross progeny developing and mobile after 48 hours of exposure to 500 mM NaCl. Paternal genotypes also contained him-8(e1489); otIs181 to generate male animals and confirm cross progeny, as previously described.
Figure 4.
Figure 4.. AAK-2 promotes ATP preservation and antagonizes glycerol metabolism to regulate C. elegans response to osmotic stress.
(a) Relative ATP/ADP ratio (measured by LC/MS) in wild-type and aak-2(ok524) mutant embryos. n = 3 replicates. Error bars – s.d. (b) Relative ATP/ADP ratios in wild-type and aak-2(ok524) mutant L1 stage animals exposed to 500 mM NaCl (and without food) or starved for 24 hours. n = 3 replicates. Error bars – s.d. (c) Relative ATP/ADP ratios in wild-type and aak-2(ok524) mutant L1 stage animals exposed to either 500 mM NaCl (without food) or starved for 72 hours. n = 3 replicates. Error bars – s.d. (d) Relative glycerol/glycerol-3-phosphate (G3P) ratio measured by GC/MS (glycerol) and LC/MS (G3P) in wild-type and aak-2(ok524) mutant embryos. n = 3 replicates. Error bars – s.d. (e) Relative glycerol/G3P ratio in wild-type and aak-2(ok524) mutant L1 stage animals exposed to either 500 mM NaCl in the absence of food or starvation for 24 hours. n = 3 replicates. Error bars – s.d. (f) Relative glycerol/G3P ratio in wild-type and aak-2(ok524) mutant L1 stage animals exposed to either 500 mM NaCl (without food) or starved for 72 hours. n = 3 replicates. Error bars – s.d. (g) Percent of wild-type, aak-2(n6251), and gpdh-2(ok1733) mutant animals developing and mobile after 24 hours of exposure to 500 mM NaCl. n = 3 replicates of >100 animals per replicate. Error bars – s.d. (h) Proposed model for how maternal exposure to osmotic stress influences offspring response to future osmotic stress.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Sieber M. H., Thomsen M. B. & Spradling A. C. Electron transport chain remodeling by GSK3 during oogenesis connects nutrient state to reproduction. Cell 164, 420–432 (2016). - PMC - PubMed
    1. Rodríguez-Nuevo A. et al. Oocytes maintain ROS-free mitochondrial metabolism by suppressing complex I. Nature 607, 756–761 (2022). - PMC - PubMed
    1. Burton N. O. et al. Insulin-like signalling to the maternal germline controls progeny response to osmotic stress. Nat. Cell Biol. 19, 252–257 (2017). - PMC - PubMed
    1. Hocaoglu H., Wang L., Yang M., Yue S. & Sieber M. Heritable shifts in redox metabolites during mitochondrial quiescence reprogramme progeny metabolism. Nat. Metab. 3, 1259–1274 (2021). - PMC - PubMed
    1. Urso S. J., Comly M., Hanover J. A. & Lamitina T. The O-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress. PLoS Genet. 16, e1008821–e1008821 (2020). - PMC - PubMed

Publication types

LinkOut - more resources