METTL3-mediated m6A methylation regulates granulosa cell autophagy during follicular atresia in porcine ovaries (2023)

Theriogenology, Band 201, 2023, S. 95-105

Storage of boar semen samples at 17°C for artificial insemination (AI) doses allows the bacteria to proliferate, necessitating antibiotics. This can contribute to the development of antimicrobial resistance (AMR). This study tested the presence of bacteria and sperm chromatin structure after using a low-density colloid (Porcicoll) as an antibiotic alternative to eliminate bacteria. Ejaculates (8 boars, 3 ejaculates each) were divided into 500 ml tubes as control and low density colloid centrifugation (single layer centrifugation, SLC, 20% and 30% Porcicoll). Analyzes were performed on days 0, 3 and 7 (17°C) for microbial presence and sperm chromatin structure analysis: % DFI (DNA fragmentation) and % HDS (chromatin immaturity), monobromobimane (mBBr; free thiols and disulfide bridges) and chromomycin A3 (CMA3; chromatin condensation). In addition to comparing bacterial presence (7 species identified) and chromatin variables between treatments, the associations between these groups of variables were described by canonical correlation analysis (CCA). The results showed a significant decrease in some bacteria or complete clearance after SLC (particularly for P30). SLC also caused a decrease in %HDS and an increase in disulfide bonds and low- and medium-mBBr populations, indicating removal of immature sperm (poor chromatin compaction). CCA showed an association pattern compatible with the degradation of sperm chromatin parameters with bacterial contamination, particularly enterobacteria.P.aeuriginosa,AndK. varicella. In summary, bacterial contamination affects sperm chromatin beyond DNA fragmentation; SLC with low density colloid not only removes bacteria from boar semen but also improves chromatin structure after selection.

Aquaculture Reports, Volume 28, 2023, Item 101468

To investigate the effects of crowding stress on the physiological mechanisms of juvenile hybrid sturgeon (♀Acipenser the baths×♂Acipenser schrenckii, 23±1g body weight) an experiment was assigned to three initial stocking densities in running waters (LD = 100 and 150 fish/m³; MD = 200 and 250 fish/m³; and HD = 300 and 350 fish/m³) for 60 days. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to identify different metabolites between different stocking densities. Final weight, weight gain rate (WGR) and specific growth rate (SGR) decreased significantly with increasing stocking density (P<0.05). Gill filaments were injured in the MD and HD groups. Constriction stress significantly increased serum cortisol and glucose levels (P<0.05) and inhibited antioxidant capacity. However, stocking density did not affect innate immunity parameters in fish, including complement c3, immunoglobulin M (IgM), and lysozyme (LZM). These negative growth performances against overcrowding stress mainly affected pathways associated with ascorbate and aldarate metabolism, butanoate metabolism, and fatty acid catabolism. Gluconeogenesis and glycogenolysis were activated by the glucagon signaling pathway to accommodate the increased energy expenditure of fish under stress, which played a protective role against lipid peroxidation. Assessing these factors allows for a more complete understanding of the underlying physiological mechanisms associated with overcrowding stress in hybrid sturgeon.

Theriogenology, Band 197, 2023, S. 116-126

In mammals, the testis is the organ with the highest transcriptional activity. After gene transcription, translation and post-translational protein modification, the transcriptional results are finally presented at the metabolic level. Metabolites, which are not only essential for cell signaling and energy transfer, but are also directly affected by the physiological and pathological changes in tissues and accurately reflect the physiological changes. The fact that the testes are oxygen-poor organs may explain why Sertoli cells and germ cells may use different metabolic pathways to obtain energy at their different developmental stages. Therefore, the study of metabolic changes during testicular development can better elucidate the metabolic profile of the testis, which is essential for uncovering characteristic metabolic pathways. The present study applied a large-scale UPLC-MS/MS-based metabolomics approach with large-scale detection, identification, and quantification to investigate the widespread metabolic changes during testicular development of Tibetan sheep. First, a total of 847 metabolites were detected in the sheep testicles and their changes as well as the three testicular development stages were further investigated. The results showed that these metabolites were grouped into amino acids and their derivatives, carbohydrates and their derivatives, organic acids and their derivatives, benzene and substituted derivatives, alcohols and amines, lipids, nucleotides and their derivatives, bile acids, coenzymes and vitamins, and hormones hormone-related compounds, etc. Among them, the most abundant metabolites in the testes were amino acids and lipid metabolites. The results showed that most lipids, carbohydrates with their derivatives, and alcohol and amine metabolites were high in sexually immature sheep, while organic acids, amino acids, and nucleotides showed a continuously increasing trend along with testicular developmental stages. Among them, levels of metabolites with antioxidant activity increased along with testicular development, while those associated with energy synthesis were downregulated with age. Further correlation analysis of each metabolite-metabolite pair emphasized the mutual influence between different metabolites throughout testicular development, suggesting a significant correlation between lipids and other metabolites. Finally, based on KEGG pathway analysis, we found that the metabolic pathways in Tibetan sheep testicular development were mainly clustered into energy metabolism, gonadal development, and antioxidant stress. Reactive oxygen species (ROS) are by-products of normal cellular metabolism and are unavoidable during testicular energy metabolism. Thus, the antioxidant stress function is a key process in maintaining the normal physiological function of the testicles. These results contributed to a broader view of the testis metabolome and to a comprehensive analysis of the metabolomic variation in different developmental stages of the testis and provided us with a theoretical basis to understand the metabolic mechanism of the ovine testis.

Theriogenology, Band 201, 2023, S. 30-40

In oocytes, cytoplasmic polyadenylation and translation of maternal mRNAs is regulatedcis-Elements including polyadenylation signal (PAS) and cytoplasmic polyadenylation element (CPE) in 3'-UTR. Recent studies elucidate non-canonical polyadenylation mechanisms of translational regulation in mouse oocytes, which differs from that in Xenopus oocytes. However, it is still unclear whether this regulation works in rodent oocytes in the pet oocyte. Here, using sheep as an animal model, we cloned the 3' UTRs ofCpeb1orBtg4and ligated it into the pRK5 flagGfpVector. Variant numbers and positions of PASs and CPEs within the 3' UTRs were constructed to demonstrate their effects on translational control. Afterin vitro-Transcription and microinjection into oocytes in the fully grown germinal vesicle stage of sheep, the expression efficiency of mRNAs was demonstrated by the GFP and Flag expression. Our results indicate that: (i) PAS located at the proximal end of the 3'-UTR can mediate translation of the maternal mRNAs as long as they are distant from CPEs; (ii) the proximal PAS has a higher efficiency in regulating transcription than the distal; (iii) an increase in PAS number can promote translational activity more efficiently; (iv) a single CPE located near PAS (<50 bp) in 3' UTRs ofCpeb1orBtg4could partially suppress the translation. In 3ʹ UTRs fromBtg4two CPEs have a higher inhibitory effect, and three CPEs can completely inhibit mRNA translation. These results confirm the existence of the non-canonical mechanism in pet oocytes.

Reproductive Biology, Volume 23, Issue 2, 2023, Item 100737

Exposure to decabromodiphenyl ether (BDE-209) caused spermatogenesis disorder resulting in poor sperm quality and has become a public concern in recent years. Spermatogenesis refers to the process by which the division of spermatogonia stem cells (SSCs) produces haploid spermatozoa, including mitosis, meiosis, and spermiogenesis. However, the mechanism of mitosis, including the proliferation and differentiation of BDE-209-induced spermatogonia dysfunction, remains largely unclear. Here, our data showed that BDE-209 exposure caused deterioration in sperm quality with disruption of seminiferous tubule structure in rats. Furthermore, BDE-209 exposure damages spermatogonia proliferation and differentiation with decreasing PLZF and cKit levels in the testis. Furthermore, rats exposed to BDE-209 decreased expression of ERα, while increased expression of Wnt3a and Wnt5a occurred. Mechanistically, propipyrazoletriol (PPT, a selective ERα pathway agonist) supplementation rescued sperm quality and attenuated the impairment of spermatogonia proliferation and differentiation in BDE-209-induced rats. Therefore, ERα plays a crucial role in the proliferation and differentiation of spermatogonia during the mitotic process. In conclusion, our study clarified the role of ERα in BDE-209-induced sperm proliferation and differentiation in rats and offers potential therapeutic application in poor sperm quality induced by BDE-209 exposure.

Thoracic Surgery Clinics, 2023