bims-cebooc 2024-08-25 papers

bims-cebooc

Biomed News

on Cell biology of oocytes

Issue of 2024–08–25
twelve papers selected by
Gabriele Zaffagnini, Centre for Genomic Regulation

Mechanisms of minor pole-mediated spindle bipolarization in human oocytes.
The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis and maintain translational repression of maternal mRNA and oocyte quality.
Variants in NLRP2 and ZFP36L2, non-core components of the human subcortical maternal complex, cause female infertility with embryonic development arrest.
FOXM1 affects oxidative stress, mitochondrial function, and the DNA damage response by regulating p21 in aging oocytes.
In-depth analysis of transcriptomes in ovarian cortical follicles from children and adults reveals interfollicular heterogeneity.
Actomyosin-mediated apical constriction promotes physiological germ cell death in C. elegans.
Switching on lysosomes.
Fertility protection during chemotherapy treatment by boosting the NAD(P)+ metabolome.
SIK2 and SIK3 differentially regulate mouse granulosa cell response to exogenous gonadotropins in vivo.
VitelloTag: a tool for high-throughput cargo delivery into oocytes.
Kick-starting the zygotic genome: licensors, specifiers, and beyond.
OOCYTE MATURATION, BLASTOCYST AND EMBRYONIC DEVELOPMENT ARE MEDIATED AND ENHANCED VIA HORMESIS.

Science. 2024 Aug 23. 385(6711): eado1022

Mechanisms of minor pole-mediated spindle bipolarization in human oocytes.

Tianyu Wu, Yuxi Luo, Meiling Zhang, Biaobang Chen, Xingzhu Du, Hao Gu, Siyuan Xie, Zhiqi Pan, Ran Yu, Ruiqi Hai, Xiangli Niu, Guimin Hao, Liping Jin, Juanzi Shi, Xiaoxi Sun, Yanping Kuang, Wen Li, Qing Sang, Lei Wang.

Spindle bipolarization, the process of a microtubule mass transforming into a bipolar spindle, is a prerequisite for accurate chromosome segregation. In contrast to mitotic cells, the process and mechanism of spindle bipolarization in human oocytes remains unclear. Using high-resolution imaging in more than 1800 human oocytes, we revealed a typical state of multipolar intermediates that form during spindle bipolarization and elucidated the mechanism underlying this process. We found that the minor poles formed in multiple kinetochore clusters contribute to the generation of multipolar intermediates. We further determined the essential roles of HAUS6, KIF11, and KIF18A in spindle bipolarization and identified mutations in these genes in infertile patients characterized by oocyte or embryo defects. These results provide insights into the physiological and pathological mechanisms of spindle bipolarization in human oocytes.

DOI: https://doi.org/10.1126/science.ado1022
Mol Biol Cell. 2024 Aug 21. mbcE24050216

The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis and maintain translational repression of maternal mRNA and oocyte quality.

Mohamed T Elaswad, Mingze Gao, Victoria E Tice, Cora G Bright, Grace M Thomas, Chloe Munderloh, Nicholas J Trombley, Christya N Haddad, Ulysses G Johnson, Ashley N Cichon, Jennifer A Schisa.

The regulation of maternal mRNAs is essential for proper oogenesis, the production of viable gametes, and to avoid birth defects and infertility. Many oogenic RNA-binding proteins have been identified with roles in mRNA metabolism, some of which localize to dynamic ribonucleoprotein granules and others that appear dispersed. Here, we use a combination of in vitro condensation assays and the in vivo C. elegans oogenesis model to characterize the properties of the conserved KH-domain MEX-3 protein and to identify novel regulators of MEX-3 and three other translational regulators. We demonstrate that MEX-3 undergoes phase separation and appears to have intrinsic gel-like properties in vitro. We also identify novel roles for the CCT chaperonin and actin in preventing ectopic RNA-binding protein condensates in maturing oocytes that appear to be independent of MEX-3 folding. The CCT chaperonin and actin also oppose the expansion of ER sheets that may promote ectopic condensation of RNA-binding proteins. These novel regulators of condensation are also required for the translational repression of maternal mRNA which is essential for oocyte quality and fertility. The identification of this regulatory network may also have implications for understanding the role of hMex3 phase transitions in cancer.

DOI: https://doi.org/10.1091/mbc.E24-05-0216
Mol Hum Reprod. 2024 Aug 23. pii: gaae031. [Epub ahead of print]

Variants in NLRP2 and ZFP36L2, non-core components of the human subcortical maternal complex, cause female infertility with embryonic development arrest.

Ximan Rui, Xiaolan Zhang, Xinru Jia, Jian Han, Congjing Wang, Qiqi Cao, Ou Zhong, Jie Ding, Chun Zhao, Junqiang Zhang, Xiufeng Ling, Hong Li, Xiang Ma, Qingxia Meng, Ran Huo.

  The subcortical maternal complex (SCMC), which is vital in oocyte maturation and embryogenesis, consists of core proteins (NLRP5, TLE6, OOEP), non-core proteins (PADI6, KHDC3L, NLRP2, NLRP7) and other unknown proteins that are encoded by maternal effect genes. Some variants of SCMC genes have been linked to female infertility characterized by embryonic development arrest. However, so far, the candidate non-core SCMC components associated with embryonic development need further exploration and the pathogenic variants that have been identified are still limited. In this study, we discovered two novel variants [p.(Ala131Val) and p.(Met326Val)] of NLRP2 in patients with primary infertility displaying embryonic development arrest from large families. In vitro studies using 293 T cells and mouse oocytes respectively showed that these variants significantly decreased protein expression and caused the phenotype of embryonic development arrest. Additionally, we combined the 'DevOmics' database with the whole exome sequence data of our cohort and screened out a new candidate non-core SCMC gene ZFP36L2. Its variants [p.(Ala241Pro) and p.(Pro291dup)] were found to be responsible for embryonic development arrest. Co-immunoprecipitation experiments in 293 T cells, used to demonstrate the interaction between proteins, verified that ZFP36L2 is one of the human SCMC components, and microinjection of ZFP36L2 cRNA variants into mouse oocytes affected embryonic development. Furthermore, the ZFP36L2 variants were associated with disrupted stability of its target mRNAs, which resulted in aberrant H3K4me3 and H3K9me3 levels. These disruptions decreased oocyte quality and further developmental potential. Overall, this is the first report of ZFP36L2 as a non-core component of the human SCMC and we found four novel pathogenic variants in the NLRP2 and ZFP36L2 genes in four of 161 patients that caused human embryonic development arrest. These findings contribute to the genetic diagnosis of female infertility and provide new insights into the physiological function of SCMC in female reproduction.

Keywords:  Embryonic development arrest; SCMC; female infertility; genetic variants; non-core components

DOI:  https://doi.org/10.1093/molehr/gaae031
Theriogenology. 2024 Aug 10. pii: S0093-691X(24)00330-3. [Epub ahead of print]229 66-74

FOXM1 affects oxidative stress, mitochondrial function, and the DNA damage response by regulating p21 in aging oocytes.

Wenjie Yu, Xiaoshi Cai, Chen Wang, Xinyue Peng, Lingxia Xu, Yan Gao, Tian Tian, Guangying Zhu, Yuan Pan, Hongzhong Chu, Shuang Liang, Chengzhen Chen, Nam-Hyung Kim, Bao Yuan, Jiabao Zhang, Hao Jiang.

  Fertilization capacity and embryo survival rate are decreased in postovulatory aging oocytes, which results in a reduced reproductive rate in female animals. However, the key regulatory genes and related regulatory mechanisms involved in the process of postovulatory aging in oocytes remain unclear. In this study, RNA-Seq revealed that 3237 genes were differentially expressed in porcine oocytes between the MII and aging stages (MII + 24 h). The expression level of FOXM1 was increased at the aging stage, and FOXM1 was also observed to be enriched in many key biological processes, such as cell senescence, response to oxidative stress, and transcription, during porcine oocyte aging. Previous studies have shown that FOXM1 is involved in the regulation of various biological processes, such as oxidative stress, DNA damage repair, mitochondrial function, and cellular senescence, which suggests that FOXM1 may play a crucial role in the process of postovulatory aging. Therefore, in this study, we investigated the effects and mechanisms of FOXM1 on oxidative stress, mitochondrial function, DNA damage, and apoptosis during oocyte aging. Our study revealed that aging oocytes exhibited significantly increased ROS levels and significantly decreased GSH, SOD, T-AOC, and CAT levels than did oocytes at the MII stage and that FOXM1 inhibition exacerbated the changes in these levels in aging oocytes. In addition, FOXM1 inhibition increased the levels of DNA damage, apoptosis, and cell senescence in aging oocytes. A p21 inhibitor alleviated the effects of FOXM1 inhibition on oxidative stress, mitochondrial function, and DNA damage and thus alleviated the degree of senescence in aging oocytes. These results indicate that FOXM1 plays a crucial role in porcine oocyte aging. This study contributes to the understanding of the function and mechanism of FOXM1 during porcine oocyte aging and provides a theoretical basis for preventing oocyte aging and optimizing conditions for the in vitro culture of oocytes.

Keywords:  FOXM1; Pig; Postovulatory aging; p21

DOI:  https://doi.org/10.1016/j.theriogenology.2024.08.010
Nat Commun. 2024 Aug 21. 15(1): 6989

In-depth analysis of transcriptomes in ovarian cortical follicles from children and adults reveals interfollicular heterogeneity.

Ilmatar Rooda, Jasmin Hassan, Jie Hao, Magdalena Wagner, Elisabeth Moussaud-Lamodière, Kersti Jääger, Marjut Otala, Katri Knuus, Cecilia Lindskog, Kiriaki Papaikonomou, Sebastian Gidlöf, Cecilia Langenskiöld, Hartmut Vogt, Per Frisk, Johan Malmros, Timo Tuuri, Andres Salumets, Kirsi Jahnukainen, Agne Velthut-Meikas, Pauliina Damdimopoulou.

The ovarian cortical reserve of follicles is vital for fertility. Some medical treatments are toxic to follicles, leading to premature ovarian insufficiency. Ovarian tissue cryopreservation is an established method to preserve fertility in adults and even applied in prepuberty despite unproven efficacy. Here, we analyze transcriptomes of 120 cortical follicles from children and adults for detailed comparison. We discover heterogeneity with two main types of follicles in both age groups: one with expected oocyte-granulosa profiles and another with predicted role in signaling. Transcriptional changes during growth to the secondary stage are similar overall in children and adults, but variations related to extracellular matrix, theca cells, and miRNA profiles are found. Notably, cyclophosphamide dose correlates with interferon signaling in child follicles. Additionally, morphology alone is insufficient for follicle categorization suggesting a need for additional markers. Marker genes for early follicle activation are determined. These findings will help refine follicular classification and fertility preservation techniques across critical ages.

DOI: https://doi.org/10.1038/s41467-024-51185-0
PLoS Biol. 2024 Aug 23. 22(8): e3002775

Actomyosin-mediated apical constriction promotes physiological germ cell death in C. elegans.

Tea Kohlbrenner, Simon Berger, Ana Cristina Laranjeira, Tinri Aegerter-Wilmsen, Laura Filomena Comi, Andrew deMello, Alex Hajnal.

Germ cell apoptosis in Caenorhabditis elegans hermaphrodites is a physiological process eliminating around 60% of all cells in meiotic prophase to maintain tissue homeostasis. In contrast to programmed cell death in the C. elegans soma, the selection of germ cells undergoing apoptosis is stochastic. By live-tracking individual germ cells at the pachytene stage, we found that germ cells smaller than their neighbors are selectively eliminated through apoptosis before differentiating into oocytes. Thus, cell size is a strong predictor of physiological germ cell death. The RAS/MAPK and ECT/RHO/ROCK pathways together regulate germ cell size by controlling actomyosin constriction at the apical rachis bridges, which are cellular openings connecting the syncytial germ cells to a shared cytoplasmic core. Enhancing apical constriction reduces germ cell size and increases the rate of cell death while inhibiting the actomyosin network in the germ cells prevents their death. We propose that actomyosin contractility at the rachis bridges of the syncytial germ cells amplifies intrinsic disparities in cell size. Through this mechanism, the animals can adjust the balance between physiological germ cell death and oocyte differentiation.

DOI: https://doi.org/10.1371/journal.pbio.3002775
Elife. 2024 Aug 21. pii: e102430. [Epub ahead of print]13

Switching on lysosomes.

Deepak Adhikari, John Carroll.

  The formation of large endolysosomal structures in unfertilized eggs ensures that lysosomes remain dormant before fertilization, and then shift into clean-up mode after the egg-to-embryo transition.

Keywords:  ELYSA; cell biology; developmental biology; embryo; endosome; fertilization; lysosome; mouse; oocyte

DOI:  https://doi.org/10.7554/eLife.102430
EMBO Mol Med. 2024 Aug 21.

Fertility protection during chemotherapy treatment by boosting the NAD(P)+ metabolome.

Wing-Hong Jonathan Ho, Maria B Marinova, Dave R Listijono, Michael J Bertoldo, Dulama Richani, Lynn-Jee Kim, Amelia Brown, Angelique H Riepsamen, Safaa Cabot, Emily R Frost, Sonia Bustamante, Ling Zhong, Kaisa Selesniemi, Derek Wong, Romanthi Madawala, Maria Marchante, Dale M Goss, Catherine Li, Toshiyuki Araki, David J Livingston, Nigel Turner, David A Sinclair, Kirsty A Walters, Hayden A Homer, Robert B Gilchrist, Lindsay E Wu.

  Chemotherapy induced ovarian failure and infertility is an important concern in female cancer patients of reproductive age or younger, and non-invasive, pharmacological approaches to maintain ovarian function are urgently needed. Given the role of reduced nicotinamide adenine dinucleotide phosphate (NADPH) as an essential cofactor for drug detoxification, we sought to test whether boosting the NAD(P)+ metabolome could protect ovarian function. We show that pharmacological or transgenic strategies to replenish the NAD+ metabolome ameliorates chemotherapy induced female infertility in mice, as measured by oocyte yield, follicle health, and functional breeding trials. Importantly, treatment of a triple-negative breast cancer mouse model with the NAD+ precursor nicotinamide mononucleotide (NMN) reduced tumour growth and did not impair the efficacy of chemotherapy drugs in vivo or in diverse cancer cell lines. Overall, these findings raise the possibility that NAD+ precursors could be a non-invasive strategy for maintaining ovarian function in cancer patients, with potential benefits in cancer therapy.

Keywords:  Infertility; Nicotinamide Adenine Dinucleotide (NAD+); Nicotinamide Mononucleotide (NMN); Oncofertility; Ovarian Toxicity

DOI:  https://doi.org/10.1038/s44321-024-00119-w
Endocrinology. 2024 Aug 19. pii: bqae107. [Epub ahead of print]

SIK2 and SIK3 differentially regulate mouse granulosa cell response to exogenous gonadotropins in vivo.

Emily T Hayes, Mariam Hassan, Oliwia Lakomy, Rachael Filzen, Marah Armouti, Marc Foretz, Noriyuki Tsumaki, Hiroshi Takemori, Carlos Stocco.

  Salt-inducible kinases (SIKs), a family of serine/threonine kinases, were found to be critical determinants of female fertility. SIK2 silencing results in increased ovulatory response to gonadotropins. In contrast, SIK3 knockout results in infertility, gonadotropin insensitivity, and ovaries devoid of antral and preovulatory follicles. This study hypothesizes that SIK2 and SIK3 differentially regulate follicle growth and fertility via contrasting actions in the granulosa cells (GCs), the somatic cells of the follicle. Therefore, SIK2 or SIK3 GC-specific knockdown (SIK2GCKD and SIK3GCKD, respectively) mice were generated by crossing SIK floxed mice with Cyp19a1pII-Cre mice. Fertility studies revealed that pup accumulation over six months and the average litter size of SIK2GCKD mice are similar to controls, though SIK3GCKD mice are significantly lower compared to controls. Compared to controls, gonadotropin stimulation of prepubertal SIK2GCKD mice results in significantly higher serum estradiol levels, whereas SIK3GCKD mice produced significantly less estradiol. Cyp11a1, Cyp19a1, and StAR were significantly increased in the GCs of gonadotropin-stimulated SIK2GCKD mice. However, Cyp11a1 and StAR remained significantly lower than controls in SIK3GCKD mice. Interestingly, Cyp19a1 stimulation in SIK3GCKD was not statistically different compared to controls. Superovulation resulted in SIK2GCKD mice ovulating significantly more oocytes, whereas SIK3GCKD mice ovulated significantly fewer oocytes than controls. Remarkably, SIK3GCKD superovulated ovaries contained significantly more preantral follicles than controls. SIK3GCKD ovaries contained significantly more apoptotic cells and fewer proliferating cells than controls. This data points to the differential regulation of GC function and follicle development by SIK2 and SIK3 and supports the therapeutic potential of targeting these kinases for treating infertility or developing new contraceptives.

Keywords:  SIK2; SIK3; female fertility; granulosa cells; ovary

DOI:  https://doi.org/10.1210/endocr/bqae107
Development. 2024 Aug 22. pii: dev.202857. [Epub ahead of print]

VitelloTag: a tool for high-throughput cargo delivery into oocytes.

D Nathaniel Clarke, Akshay Kane, Margherita Perillo, Christopher J Lowe, S Zachary Swartz.

  Delivering molecular tools into oocytes is essential for developmental and reproductive biology. Microinjection, the conventional method, is equipment-intensive, often technically challenging, and low-yield, and is impractical in species with delicate oocytes or restricted spawning seasons. To overcome these limitations, we developed VitelloTag, a cost-effective, high-throughput system using vitellogenin-derived fusion proteins to enable efficient cargo delivery via receptor-mediated endocytosis. We demonstrate its utility by delivering Cas9/sgRNA complexes in two distantly related species for gene knockout.

Keywords:  CRISPR/Cas9; Gene editing; Oocyte delivery; Transgenesis; Vitellogenesis

DOI:  https://doi.org/10.1242/dev.202857
EMBO Rep. 2024 Aug 19.

Kick-starting the zygotic genome: licensors, specifiers, and beyond.

Zhuoning Zou, Qiuyan Wang, Xi Wu, Richard M Schultz, Wei Xie.

  Zygotic genome activation (ZGA), the first transcription event following fertilization, kickstarts the embryonic program that takes over the control of early development from the maternal products. How ZGA occurs, especially in mammals, is poorly understood due to the limited amount of research materials. With the rapid development of single-cell and low-input technologies, remarkable progress made in the past decade has unveiled dramatic transitions of the epigenomes, transcriptomes, proteomes, and metabolomes associated with ZGA. Moreover, functional investigations are yielding insights into the key regulators of ZGA, among which two major classes of players are emerging: licensors and specifiers. Licensors would control the permission of transcription and its timing during ZGA. Accumulating evidence suggests that such licensors of ZGA include regulators of the transcription apparatus and nuclear gatekeepers. Specifiers would instruct the activation of specific genes during ZGA. These specifiers include key transcription factors present at this stage, often facilitated by epigenetic regulators. Based on data primarily from mammals but also results from other species, we discuss in this review how recent research sheds light on the molecular regulation of ZGA and its executors, including the licensors and specifiers.

Keywords:  Early Embryo; Licensor; Specifier; Transcription Factor; ZGA

DOI:  https://doi.org/10.1038/s44319-024-00223-5
Food Chem Toxicol. 2024 Aug 15. pii: S0278-6915(24)00507-6. [Epub ahead of print] 114941

OOCYTE MATURATION, BLASTOCYST AND EMBRYONIC DEVELOPMENT ARE MEDIATED AND ENHANCED VIA HORMESIS.

Edward J Calabrese, Peter Pressman, A Wallace Hayes, Gaurav Dhawan, Rachna Kapoor, Evgenios Agathokleous, Vittorio Calabrese.

  The present paper provides the first integrative assessment of the capacity of dietary, endogenous and other agents to induce hormetic dose responses in oocytes, their supportive cells such as granulosa cells, blastocyst formation and early stage embryo development with the goal of improving fertility and reproductive success. The analysis showed that numerous agents enhance oocyte maturation and blastocyst/embryonic development in an hormetic fashion. These findings indicate that numerous agents improve oocyte related biological functioning under normal conditions as well as enhancing its capacity to prevent damage from numerous chemical toxins and related stressor agents, including heat and age-related processes in pre-post conditioning and concurrent exposures. The present assessment suggests that hormetic based lifestyles and dietary interventions may offer the potential to enhance healthy reproductive performance with applications to animal husbandry and human biology. The present findings also significantly extend the generality of the hormesis dose response concept to multiple fundamental biological processes (i.e., oocyte maturation, fertilization and blastocyst/embryo development).

Keywords:  blastocyst; dose response; embryo; granulosa cells; hormesis; oocyte

DOI:  https://doi.org/10.1016/j.fct.2024.114941