Mitochondrial metabolic substrate utilization in granulosa cells reflects body mass index and total follicle stimulating hormone dosage in in vitro fertilization patients

Relationship between melanoma vemurafenib tolerance thresholds and metabolic pathway choice and Wnt signaling involvement

Vemurafenib constitutes an important therapeutic for BRAFV600 mutant melanomas, but despite high initial response rates, resistance to BRAF and MEK inhibitors quickly develops. Here, we performed an integrative analysis of metabolomic consequences and transcriptome alterations to uncover mechanisms involved in adaptive vemurafenib resistance (VemR) development and their relationship with vemurafenib tolerance thresholds. We developed BRAFV600E isogenic models of VemR utilizing M14 and A2058 lines, and patient-derived melanomas with V600E or normal BRAF to verify vemurafenib selectivity. MEK or PI3K inhibitors only partially inhibited VemR cell proliferation, indicating cross-resistance to these inhibitors. MITF and β-catenin levels were induced and treatment with Wnt/β-catenin inhibitor ICG-001 restored vemurafenib sensitivity with concomitant reductions in β-catenin-regulated gene expressions, phospho-ERK1/2, and VemR-induced mitochondrial mass and respiration. Targeted metabolite, MitoPlate-S1, Mito-stress and transcriptome/metabolomic analysis showed that melanoma cells with elevated vemurafenib tolerance thresholds such as A2058 VemR cells utilize Wnt/β-catenin signaling for mitochondrial metabolism while VemR cells with low tolerance such as M14 VemR cells rely on Wnt/β-catenin signaling for pentose phosphate pathway. Pathways associated with cytokine-cytokine receptor, ECM receptor, and neuroactive ligand receptor interactions were similarly enriched in BRAFV600E patient-derived melanoma as M14 and A2058 cells whereas distinct pathways involving cell cycle, DNA replication, Fanconi anemia and DNA repair pathways are upregulated in wild type BRAF expressing patient derived melanoma. These data show for the first time that the metabolic pathway choices made by VemR BRAF mutant melanomas are controlled by vemurafenib tolerance and endurance thresholds and Wnt/β-catenin signaling plays a central role in coordinating expression of genes controlling VemR and metabolic pathway shifts.

Identification and validation of novel genes related to immune microenvironment in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most complicated chronic inflammatory diseases in women of reproductive age and is one of the primary factors responsible for infertility. There is substantial dispute relating to the pathophysiology of PCOS. Consequently, there is a critical need for further research to identify the factors underlying the pathophysiology of PCOS. Three transcriptome profiles of granulosa cells from patients with PCOS and normal controls were obtained from the gene expression integration database. We also obtained relevant microarrays of granulocytes prepared from PCOS patients and normal controls from the gene expression integration database. Then, we used the R package to perform correlations and identify differences between PCOS and normal controls with regard to immune infiltrating cells and functionality. Subsequently, intersecting genes were identified and risk models were constructed. Finally, the results were validated by enzyme linked immunosorbent assay and real-time PCR. We identified 8 genes related to cuproptosis (SLC31A1, PDHB, PDHA1, DLST, DLD, DLAT, DBT, and ATP7A) and 5 genes related to m7G (SNUPN, NUDT16, GEMIN5, DCPS, and EIF4E3) that were associated with immune infiltration. Furthermore, the expression levels of DLAT (P = .049) and NUDT16 (P = .024) differed significantly between the PCOS patients and normal controls, as revealed by multifactorial analysis. Both DLAT and NUDT16 were negatively correlated with immune cell expression and function and expression levels were significantly lower in the PCOS group. Finally, real-time PCR and enzyme linked immunosorbent assay demonstrated that the expression levels of DLAT and NUDT16 were significantly reduced in the granulosa cells of PCOS patients. In conclusion, our findings shed fresh light on the roles of immune infiltration, cuproptosis, and m7G alternations in PCOS. We also provide a reliable biomarker for the pathological classification of PCOS patients.

Maturational competence of equine oocytes is associated with alterations in their 'cumulome'

Assisted reproductive technologies are an emerging field in equine reproduction, with species-dependent peculiarities, such as the low success rate of conventional IVF. Here, the 'cumulome' was related to the developmental capacity of its corresponding oocyte. Cumulus-oocyte complexes collected from slaughterhouse ovaries were individually matured, fertilized by ICSI, and cultured. After maturation, the cumulus was collected for proteomics analysis using label-free mass spectrometry (MS)-based protein profiling by nano-HPLC MS/MS and metabolomics analysis by UPLC-nanoESI MS. Overall, a total of 1671 proteins and 612 metabolites were included in the quantifiable 'cumulome'. According to the development of the corresponding oocytes, three groups were compared with each other: not matured (NM; n = 18), cleaved (CV; n = 15), and blastocyst (BL; n = 19). CV and BL were also analyzed together as the matured group (M; n = 34). The dataset revealed a closer connection within the two M groups and a more distinct separation from the NM group. Overrepresentation analysis detected enrichments related to energy metabolism as well as vesicular transport in the M group. Functional enrichment analysis found only the KEGG pathway 'oxidative phosphorylation' as significantly enriched in the NM group. A compound attributed to ATP was observed with significantly higher concentrations in the BL group compared with the NM group. Finally, in the NM group, proteins related to degradation of glycosaminoglycans were lower and components of cumulus extracellular matrix were higher compared to the other groups. In summary, the study revealed novel pathways associated with the maturational and developmental competence of oocytes.

Granulosa cell metabolism at ovulation correlates with oocyte competence and is disrupted by obesity and aging

STUDY QUESTION

Is oocyte developmental competence associated with changes in granulosa cell (GC) metabolism?

SUMMARY ANSWER

GC metabolism is regulated by the LH surge, altered by obesity and reproductive aging, and, in women, specific metabolic profiles are associated with failed fertilization versus increased blastocyst development.

WHAT IS KNOWN ALREADY

The cellular environment in which an oocyte matures is critical to its future developmental competence. Metabolism is emerging as a potentially important factor; however, relative energy production profiles between GCs and cumulus cells and their use of differential substrates under normal in vivo ovulatory conditions are not well understood.

STUDY DESIGN, SIZE, DURATION

This study identified metabolic and substrate utilization profiles within ovarian cells in response to the LH surge, using mouse models and GCs of women undergoing gonadotropin-induced oocyte aspiration followed by IVF/ICSI.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To comprehensively assess follicular energy metabolism, we used real-time metabolic analysis (Seahorse XFe96) to map energy metabolism dynamics (mitochondrial respiration, glycolysis, and fatty acid oxidation) in mouse GCs and cumulus-oocyte complexes (COCs) across a detailed time course in the lead up to ovulation. In parallel, the metabolic profile of GCs was measured in a cohort of 85 women undergoing IVF/ICSI (n = 21 with normal ovarian function; n = 64 with ovarian infertility) and correlated with clinical parameters and cycle outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

Our study reveals dynamic changes in GC energy metabolism in response to ovulatory LH, with mitochondrial respiration and glycolysis differentially affected by obesity versus aging, in both mice and women. High respiration in GCs is associated with failed fertilization (P < 0.05) in a subset of women, while glycolytic reserve and mitochondrial ATP production are correlated with on-time development at Day 3 (P < 0.05) and blastocyst formation (P < 0.01) respectively. These data provide new insights into the cellular mechanisms of infertility, by uncovering significant associations between metabolism within the ovarian follicle and oocyte developmental competence.

LIMITATIONS, REASONS FOR CAUTION

A larger prospective study is needed before the metabolic markers that were positively and negatively associated with oocyte quality can be used clinically to predict embryo outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

This study offers new insights into the importance of GC metabolism for subsequent embryonic development and highlights the potential for therapeutic strategies focused on optimizing mitochondrial metabolism to support embryonic development.

STUDY FUNDING/COMPETING INTEREST(S)

National Health and Medical Research Council (Australia). The authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Omics data integration suggests a potential idiopathic Parkinson's disease signature

The vast majority of Parkinson's disease cases are idiopathic. Unclear etiology and multifactorial nature complicate the comprehension of disease pathogenesis. Identification of early transcriptomic and metabolic alterations consistent across different idiopathic Parkinson's disease (IPD) patients might reveal the potential basis of increased dopaminergic neuron vulnerability and primary disease mechanisms. In this study, we combine systems biology and data integration approaches to identify differences in transcriptomic and metabolic signatures between IPD patient and healthy individual-derived midbrain neural precursor cells. Characterization of gene expression and metabolic modeling reveal pyruvate, several amino acid and lipid metabolism as the most dysregulated metabolic pathways in IPD neural precursors. Furthermore, we show that IPD neural precursors endure mitochondrial metabolism impairment and a reduced total NAD pool. Accordingly, we show that treatment with NAD precursors increases ATP yield hence demonstrating a potential to rescue early IPD-associated metabolic changes.

Acyl-Carnitines Exert Positive Effects on Mitochondrial Activity under Oxidative Stress in Mouse Oocytes: A Potential Mechanism Underlying Carnitine Efficacy on PCOS

Carnitines play a key physiological role in oocyte metabolism and redox homeostasis. In clinical and animal studies, carnitine administration alleviated metabolic and reproductive dysfunction associated with polycystic ovarian syndrome (PCOS). Oxidative stress (OS) at systemic, intraovarian, and intrafollicular levels is one of the main factors involved in the pathogenesis of PCOS. We investigated the ability of different acyl-carnitines to act at the oocyte level by counteracting the effects of OS on carnitine shuttle system and mitochondrial activity in mouse oocytes. Germinal vesicle (GV) oocytes were exposed to hydrogen peroxide and propionyl-l-carnitine (PLC) alone or in association with l-carnitine (LC) and acetyl-l-carnitine (ALC) under different conditions. Expression of carnitine palmitoyltransferase-1 (Cpt1) was monitored by RT-PCR. In in vitro matured oocytes, metaphase II (MII) apparatus was assessed by immunofluorescence. Oocyte mitochondrial respiration was evaluated by Seahorse Cell Mito Stress Test. We found that Cpt1a and Cpt1c isoforms increased under prooxidant conditions. PLC alone significantly improved meiosis completion and oocyte quality with a synergistic effect when combined with LC + ALC. Acyl-carnitines prevented Cpt1c increased expression, modifications of oocyte respiration, and ATP production observed upon OS. Specific effects of PLC on spare respiratory capacity were observed. Therefore, carnitine supplementation modulated the intramitochondrial transfer of fatty acids with positive effects on mitochondrial activity under OS. This knowledge contributes to defining molecular mechanism underlying carnitine efficacy on PCOS.

High body energy reserve influences extracellular vesicles miRNA contents within the ovarian follicle

Aiming to evaluate the effects of increased body energy reserve (BER) in Nellore cows' reproductive efficiency, cows were fed with different nutritional plans to obtain animals with high BER (HBER; Ad libitum diet) and moderate BER (MBER: cows fed 70% of HBER group ingestion). To evaluate the BER, cows were weekly weighted and evaluated for subcutaneous fat thickness and insulin serum concentration along the experimental period. At the end of the experimental period, animals were submitted to estrous synchronization and artificial insemination. Animals were slaughtered approximately 120 h after ovulation induction and the reproductive tracts were collected for embryo recovery and samples collection. Cumulus-oocyte-complexes (COC) and follicular fluid were collected from 3-6 mm in diameter ovarian follicles to perform miRNA analysis of cumulus cells (CC) and extracellular vesicles from follicular fluid (EV FF). As expected, differences were observed among MBER and HBER groups for body weight, fat thickness, and insulin serum concentration. HBER animals showed lower ovulation and embryo recovery rates compared to MBER animals. Different miRNAs were found among CC and EV FF within groups, suggesting that the BER may influence follicular communication. This suggests that small follicles (3-6 mm diameter) are already under BER effects, which may be greater on later stages of follicular development.

Carnitines as Mitochondrial Modulators of Oocyte and Embryo Bioenergetics

Recently, the importance of bioenergetics in the reproductive process has emerged. For its energetic demand, the oocyte relies on numerous mitochondria, whose activity increases during embryo development under a fine regulation to limit ROS production. Healthy oocyte mitochondria require a balance of pyruvate and fatty acid oxidation. Transport of activated fatty acids into mitochondria requires carnitine. In this regard, the interest in the role of carnitines as mitochondrial modulators in oocyte and embryos is increasing. Carnitine pool includes the un-esterified l-carnitine (LC) and carnitine esters, such as acetyl-l-carnitine (ALC) and propionyl-l-carnitine (PLC). In this review, carnitine medium supplementation for counteracting energetic and redox unbalance during in vitro culture and cryopreservation is reported. Although most studies have focused on LC, there is new evidence that the addition of ALC and/or PLC may boost LC effects. Pathways activated by carnitines include antiapoptotic, antiglycative, antioxidant, and antiinflammatory signaling. Nevertheless, the potential of carnitine to improve energetic metabolism and oocyte and embryo competence remains poorly investigated. The importance of carnitine as a mitochondrial modulator may suggest that this molecule may exert a beneficial role in ovarian disfunctions associated with metabolic and mitochondrial alterations, including PCOS and reproductive aging.

Regulation of ovarian function by growth hormone: Potential intervention of ovarian aging

Growth hormone (GH) is mainly secreted by eosinophils of anterior pituitary gland. GH plays an important role in regulating the growth and development of many tissues and cells, so it is used in the treatment of many diseases. In recent years, the regulation of GH on ovarian function has attracted much attention. GH has been applied in controlled ovarian hyperstimulation, particularly in the patients with advanced age, diminished ovarian reserve (DOR) and poor ovarian response (POR). GH can directly bind to the growth hormone receptor (GHR) on the ovary to promote the growth, maturation and ovulation of follicles, as well as to inhibit follicular atresia. GH so as to promote the occurrence of early follicles, enhance the sensitivity of follicles to gonadotropins, accelerate the maturation of oocyte nucleus, improve mitochondrial activity and the quality of oocytes through the insulin-like growth factor (IGF) system, which is an indirect regulation. The deep-seated effects of GH on human reproduction and ovarian aging need further basic research and clinical practice.

Modelling Metabolic Shifts during Cardiomyocyte Differentiation, Iron Deficiency and Transferrin Rescue Using Human Pluripotent Stem Cells

Cardiomyocytes rely on specialised metabolism to meet the high energy demand of the heart. During heart development, metabolism matures and shifts from the predominant utilisation of glycolysis and glutamine oxidation towards lactate and fatty acid oxidation. Iron deficiency (ID) leads to cellular metabolism perturbations. However, the exact alterations in substrate metabolism during ID are poorly defined. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), the present study investigated changes in major metabolic substrate utilisation in the context of ID or upon transferrin rescue. Typically, during hiPSC-CM differentiation, the greatest increase in total metabolic output and rate was seen in fatty acid metabolism. When ID was induced, hiPSC-CMs displayed increased reliance on glycolytic metabolism, and six TCA cycle, five amino acid, and four fatty acid substrates were significantly impaired. Transferrin rescue was able to improve TCA cycle substrate metabolism, but the amino acid and fatty acid metabolism remained perturbed. Replenishing iron stores partially reverses the adverse metabolic changes that occur during ID. Understanding the changes in metabolic substrate utilisation and their modification may provide potential for discovery of new biomarkers and therapeutic targets in cardiovascular diseases.