Plasma metabolomic characterization of premature ovarian insufficiency

AARS2-catalyzed lactylation induces follicle development and premature ovarian insufficiency

Lactate, a metabolite which is elevated in various developmental and pathological processes, exerts its signal through alanyl tRNA synthetases (AARS)-catalyzed protein lactylation. Herein, we report that elevated lactate and gain-of-function mitochondrial AARS (AARS2) mutations-induced hyper-lactylation promotes premature ovarian insufficiency (POI). Serum lactate is elevated in POI patients. POI-driving AARS2 mutations gain lactyltransferase activity. AARS2 lactylates and inactivates carnitine palmitoyl transferase 2 (CPT2), resulting in FFA accumulation that activates peroxisome proliferator-activated receptor γ (PPARγ), and potentiates follicle-stimulating hormone (FSH) to initiate follicle development. These, in synergy with the anabolites accumulation effects of AARS2, promoted lactylation-induced PDHA1 inactivation promote granular cell (GC) proliferation and primordial follicle development. GC-specific AARS2 overexpression does not affect primordial follicle number but speed up follicle depletion. AARS2 ablation or lactylation-inhibiting β-alanine treatments can prevent folliculogenesis and POI traits in mouse. These findings reveal that lactate signal drives follicle development, and inhibiting lactate signal could treat/prevent POI.

Untargeted metabolomics reveals homogeneity and heterogeneity between physiological and pathological ovarian aging

BACKGROUND

Ovarian aging is the main cause of reduced reproductive life span, yet its metabolic profiles remain poorly understood. This study aimed to reveal the metabolic homogeneity and heterogeneity between physiological and pathological ovarian aging.

METHODS

Seventy serum samples from physiological ovarian aging participants, pathological ovarian aging participants (including diminished ovarian reserve (DOR), subclinical premature ovarian insufficiency (scPOI) and premature ovarian insufficiency (POI)), as well as healthy participants were collected and analyzed by untargeted metabolomics.

RESULTS

Five homogeneous differential metabolites (neopterin, menaquinone, sphingomyelin (SM) (d14:1/24:2), SM (d14:0/21:1) and SM (d17:0/25:1)) were found in both physiological and pathological ovarian aging. While five distinct metabolites, including phosphoglyceride (PC) (17:0/18:2), PC (18:2e/17:2), SM (d22:1/14:1), SM (d14:1/20:1) and 4-hydroxyretinoic acid were specific to pathological ovarian aging. Functional annotation of differential metabolites suggested that folate biosynthesis, ubiquinone and other terpenoid-quinone biosynthesis pathways, were mainly involved in the ovarian aging process. Meanwhile, dopaminergic synapses pathway was strongly associated with scPOI, vitamin digestion and absorption and retinol metabolism were associated with POI. Furthermore, testosterone sulfate, SM (d14:0/28:1), PC (18:0e/4:0) and 4-hydroxyretinoic acid, were identified as potential biomarkers for diagnosing physiological ovarian aging, DOR, scPOI, and POI, respectively. Additionally, SM (d14:1/24:2) strongly correlated with both physiological and pathological ovarian aging. 4-hydroxyretinoic acid was strongly correlated with pathological ovarian aging.

CONCLUSIONS

Metabolic homogeneity of physiological and pathological ovarian aging was related to disorders of lipid, folate, ubiquinone metabolism, while metabolic heterogeneity between them was related to disorders of lipid, vitamin and retinol metabolism.

CLINICAL TRIAL NUMBER

Not applicable.

The microbial communities and metabolic profiles of follicular fluid in patients with premature ovarian insufficiency

Introduction

Premature ovarian insufficiency (POI) is a condition characterized by ovarian dysfunction occurring before the age of 40, and its etiology is multifactorial, including genetic, immunological, infectious, environmental, and iatrogenic factors, with over half of the cases remaining unexplained. Whether the microbial communities and metabolites in follicular fluid, which is the direct microenvironment for oocyte survival, are related to POI has not been reported.

Methods

In this study, Follicular fluid samples of 26 patients with POI and 27 controls with a normal ovarian reserve were collected and analyzed using 16S rDNA sequencing and untargeted metabolomics. Conjoint analysis was performed to identify key microbial communities and metabolites that might be involved in POI.

Results

Patients with POI exhibited significant alterations in microbial richness and diversity and metabolic profile in their follicular fluid. The downregulation of ABC transporters and upregulation of the citrate cycle (TCA cycle) might be critical for the development and progression of POI. G-Rhodopseudomonas and g-Caulobacter were identified as key microbial genera, while L-aspartic acid, citrate, isoleucine, and cytidine were identified as key metabolites.

Discussion

These findings offer novel insights into the pathogenesis of POI and might pave the way for improved clinical outcomes for individuals with POI.

Hypoxic mesenchymal stem cell-derived exosomal circDennd2a regulates granulosa cell glycolysis by interacting with LDHA

BACKGROUND

Premature ovarian insufficiency (POI) is an ovarian dysfunction disorder that significantly impacts female fertility. Ovarian granulosa cells (GCs) are crucial somatic components supporting oocyte development that rely on glycolysis for energy production, which is essential for follicular growth. Hypoxia-induced exosomal circRNAs regulate glycolysis, but their biological functions and molecular mechanisms in POI are largely unexplored. The present comprehensive investigation revealed a substantial reduction in ovarian glycolysis levels in POI rats. Notably, hypoxia-induced exosomes originating from mesenchymal stem cells (HM-Exs) exhibit a remarkable capacity to enhance ovarian glycolysis, mitigate GCs apoptosis, reinstate disrupted estrous cycles, modulate sex hormone levels, and curtail the presence of atretic follicles. These restorative actions collectively contribute to fostering fertility revival in POI-afflicted rats.

METHODS

Cyclophosphamide was administered for 2 weeks to induce POI rat model, and POI rats were randomly divided into three groups and treated with PBS, NM-Exs and HM-Exs, respectively. Ovarian function and fertility were assessed at the end of the study and ovarian tissues were collected for analysis of energy metabolites. The relationship between circDennd2a and POI was explored in vitro by qRT-PCR, Western blotting, CCK-8 assay, EdU staining, TUNEL staining, extracellular acidification rate (ECAR) measurements, and ATP, lactate and pyruvate level assays.

RESULTS

Our findings revealed depletion of circDennd2a in serum samples and GCs from individuals suffering from POI. The introduction of HM-Exs-derived circDennd2a (HM-Exs-circDennd2a) effectively counteracted GCs apoptosis by enhancing glycolytic processes and driving cellular proliferation. CircDennd2a interacted with lactate dehydrogenase A (LDHA), which served as a catalyst to increase LDHA enzymatic activity and facilitate the conversion of NADH to NAD+. This biochemical cascade worked synergistically to sustain glycolytic function within GCs.

CONCLUSION

This study revealed that HM-Exs-circDennd2a promoted LDHA activity and enhanced GCs glycolytic capacity, both of which support its use as a potential clinical diagnostic and therapeutic target for POI.

Causal Relationship Between Endometriosis, Female Infertility, and Primary Ovarian Failure Through Bidirectional Mendelian Randomization

Background

Endometriosis and its associated gynecological diseases such as female infertility and primary ovarian failure (POF), impose a long-term disease burden on women. This study aims to explore the causal relationships between these conditions through a two-sample bidirectional Mendelian randomization (MR) study.

Methods

We utilized large-scale GWAS data and conducted bidirectional MR analyses using methods such as Inverse Variance Weighted (IVW) and MR-Egger to assess the causal relationships between endometriosis and female infertility, POF, amenorrhoea, and oligomenorrhoea.

Results

MR analysis revealed significant causal relationships between endometriosis and female infertility (OR=1.430, 95% CI 1.306-1.567, P<0.01) as well as POF (OR=1.348, 95% CI 1.050-1.731, P=0.019). Reverse MR analysis indicated causal relationships between amenorrhoea (OR=1.076, 95% CI 1.009-1.148, P=0.026) and female infertility (OR=1.340, 95% CI 1.092-1.645, P<0.01) with endometriosis. Sensitivity analyses confirmed the robustness of these findings (heterogeneity: Q_pval>0.05, pleiotropy: pval>0.05).

Conclusion

This study suggested that managing endometriosis may help prevent conditions such as female infertility and POF, and vice versa. Future research is needed to confirm these findings in more diverse populations.

Earlier Age at Menopause, Plasma Metabolome, and Risk of Premature Mortality

BACKGROUND/OBJECTIVES

Menopause and related metabolites are associated with mortality. However, the relationship between earlier menopause, premature mortality, and the role of metabolomic signatures remains underexplored. This study investigated the association between earlier menopause and premature mortality, and the mediating effect of metabolomic signatures.

METHODS

This prospective cohort study used data from the UK Biobank, including 33,687 post-menopausal women aged 40-69 years. Age at menopause was obtained from a baseline self-reported questionnaire and analyzed both as a continuous variable and in categories (<40, 40-49, and ≥50 years). Premature mortality was defined as deaths before 75 years. Cox regression was used to estimate hazard ratios (HRs), and elastic net regression identified metabolomic signatures related to menopause age. Mediation analysis was conducted to assess the proportion of the association explained by the metabolomic signature.

RESULTS

During a median follow-up of 13.7 years, 1612 cases of premature mortality occurred. Compared to menopause at ≥50 years, earlier menopause (HR 1.17, 95% CI 1.04-1.30) and premature menopause (HR 1.60, 95% CI 1.28-2.00) were associated with higher risks of premature mortality. A metabolomic signature inversely associated with premature mortality (HR per SD increment, 0.79; 95% CI, 0.75-0.83) mediated 13.6% (95% CI, 1.9%-28.3%) of the association between earlier menopause and premature mortality.

CONCLUSIONS

Earlier menopause is associated with an increased risk of premature mortality, partially mediated by a metabolomic signature related to age at menopause. These findings highlight the importance of metabolomic profiling in understanding menopause and mortality risks.

Multiomics insights into the female reproductive aging

The human female reproductive lifespan significantly diminishes with age, leading to decreased fertility, reduced fertility quality and endocrine function disorders. While many aspects of aging in general have been extensively documented, the precise mechanisms governing programmed aging in the female reproductive system remain elusive. Recent advancements in omics technologies and computational capabilities have facilitated the emergence of multiomics deep phenotyping. Through the application and refinement of various high-throughput omics methods, a substantial volume of omics data has been generated, deepening our comprehension of the pathogenesis and molecular underpinnings of reproductive aging. This review highlights current and emerging multiomics approaches for investigating female reproductive aging, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We elucidate their influence on fundamental cell biology and translational research in the context of reproductive aging, address the limitations and current challenges associated with multiomics studies, and offer a glimpse into future prospects.

Lipid and glucose metabolism in senescence

Senescence is an inevitable biological process. Disturbances in glucose and lipid metabolism are essential features of cellular senescence. Given the important roles of these types of metabolism, we review the evidence for how key metabolic enzymes influence senescence and how senescence-related secretory phenotypes, autophagy, apoptosis, insulin signaling pathways, and environmental factors modulate glucose and lipid homeostasis. We also discuss the metabolic alterations in abnormal senescence diseases and anti-cancer therapies that target senescence through metabolic interventions. Our work offers insights for developing pharmacological strategies to combat senescence and cancer.

Elevated cell-free mitochondria DNA level of patients with premature ovarian insufficiency

BACKGROUND

Premature ovarian insufficiency (POI) patients present with a chronic inflammatory state. Cell-free mitochondria DNA (cf-mtDNA) has been explored as a reliable biomarker for estimating the inflammation-related disorders, however, the cf-mtDNA levels in POI patients have never been measured. Therefore, in the presenting study, we aimed to evaluate the levels of cf-mtDNA in plasma and follicular fluid (FF) of POI patients and to determine a potential role of cf-mtDNA in predicting the disease progress and pregnancy outcomes.

METHODS

We collected plasma and FF samples from POI patients, biochemical POI (bPOI) patients and control women. Quantitative real-time PCR was used to measure the ratio of mitochondrial genome to nuclear genome of cf-DNAs extracted from the plasma and FF samples.

RESULTS

The plasma cf-mtDNA levels, including COX3, CYB, ND1 and mtDNA79, were significantly higher in overt POI patients than those in bPOI patients or control women. The plasma cf-mtDNA levels were weakly correlated with ovarian reserve, and could not be improved by regular hormone replacement therapy. The levels of cf-mtDNA in FF, rather than those in plasma, exhibited the potential to predict the pregnancy outcomes, although they were comparable among overt POI, bPOI and control groups.

CONCLUSIONS

The increased plasma cf-mtDNA levels in overt POI patients indicated its role in the progress of POI and the FF cf-mtDNA content may hold the value in predicting pregnancy outcomes of POI patients.