TGF-β1-induced collagen promotes chicken ovarian follicle development via an intercellular cooperative pattern

METTL14 mediates nerve growth factor-stimulated testosterone synthesis in porcine theca cells†

Ovarian theca cells produce testosterone, which acts as a vital precursor substance for synthesizing estrogens during follicular development. Nerve growth factor (NGF) has been shown to participate in reproductive physiology, specifically to follicular development and ovulation. There is currently no available data on the impact of NGF on testosterone synthesis in porcine theca cells. Furthermore, m6A modification is the most common internal modification in eukaryotic mRNAs that are closely associated with female gametogenesis, follicle development, ovulation, and other related processes. It is also uncertain whether the three main enzymes associated with m6A, such as Writers, Erasers, and Readers, play a role in this process. The present study, with an in vitro culture model, investigated the effect of NGF on testosterone synthesis in porcine theca cells and the role of Writers-METTL14 in this process. It was found that NGF activates the PI3K/AKT signaling pathway through METTL14, which regulates testosterone synthesis in porcine theca cells. This study will help to further elucidate the mechanisms by which NGF regulates follicular development and provide new therapeutic targets for ovary-related diseases in female animals. Summary Sentence  The present study investigated the effect of NGF on testosterone synthesis in porcine theca cells. It was found that NGF activates the PI3K/AKT signaling pathway through METTL14, which regulates testosterone synthesis in porcine theca cells.

Age-related changes in the mitochondrial, synthesis of steroids, and cellular homeostasis of the chicken ovary

In poultry reproduction, the decline of ovarian function due to aging is related to dysfunction of mitochondria exacerbated by a reduction in antioxidant capacity, ultimately leading to follicle atresia and decreased egg production. However, the mechanisms of mitochondrial dysfunction in the chicken ovary in aging have remained to be understood. Hence, this study aims to investigate the effects of aging on mitochondrial function and cellular homeostasis. We collect ovarian tissue, small white follicles (SWF), large white follicles (LWF), and small yellow follicles (SYF) from three different laying periods of hens. The transmission electron microscopy (TEM) results showed that mitochondrial damage occurred in ovarian tissue during the late laying period (LP), characterized by structural swelling, scattered mitochondrial cristae, and an increase in the vacuoles. At the same time, with age, the synthesis of steroid hormones in the ovaries and follicular tissues is reduced. The levels of autophagy and cell apoptosis in ovarian tissues were both increased in the LP. In addition, aging adversely impacts mitochondrial function, leading to a decrease in mitochondrial unfolded protein response (UPRmt) functions. This study will expand the knowledge about regressing ovarian aging in hens and increasing egg production in older layers for poultry production.

Assessing the effect of adipose-tissue-derived stem cell conditioned medium on follicles and stromal cells in bovine ovarian tissue culture

RESEARCH QUESTION

Does adipose-tissue-derived stem cell conditioned medium (ASC-CM) supplementation enhance follicle and stromal cell outcomes in vitro?

DESIGN

Bovine ovaries (n = 8) were sectioned and cultured in vitro for 8 days in two different groups: (i) standard culture (OT Ctrl D8); and (ii) culture with ASC-CM supplementation (OT + CM D8). Half of the culture medium was replaced every other day, and stored to measure the production of oestradiol. Follicle classification was established using haematoxylin and eosin staining. Follicle and stromal cell DNA fragmentation was assessed by TUNEL assays, while growth differentiation factor-9 (GDF-9) staining served as a marker of follicle quality. Additionally, three factors, namely vascular endothelial growth factor (VEGF), interleukin 6 (IL-6) and transforming growth factor beta 1 (TGF-β1), were evaluated in ASC-CM in order to appraise the potential underlying mechanisms of action of ASC.

RESULTS

The OT + CM D8 group showed a significantly higher proportion of secondary follicles (P = 0.02) compared with the OT Ctrl D8 group. The OT + CM D8 group also demonstrated significantly lower percentages of TUNEL-positive follicles (P = 0.014) and stromal cells (P = 0.001) compared with the OT Ctrl D8 group. Furthermore, follicles in the OT + CM D8 group exhibited a significant increase (P = 0.002) in expression of GDF-9 compared with those in the OT Ctrl D8 group, and oestradiol production was significantly higher (P = 0.04) in the OT + CM D8 group. All studied factors were found to be present in ASC-CM. VEGF and IL-6 were the most widely expressed factors, while TGF-β1 showed the lowest expression.

CONCLUSIONS

Addition of ASC-CM to culture medium enhances follicle survival, development and oestradiol production, and promotes the viability of stromal cells. VEGF, IL-6 and TGF-β1 could be paracrine mediators underlying the beneficial effects.

Vitamin E Regulates the Collagen Contents in the Body Wall of Sea Cucumber (Apostichopus japonicus) via Its Antioxidant Effects and the TGF-β/Smads Pathway

A 70-day feeding experiment was performed to investigate the effects of dietary vitamin E at different addition levels (0, 100, 200, and 400 mg/kg) on the growth, collagen content, antioxidant capacity, and expressions of genes related to the transforming growth factor beta (TGF-β)/Sma- and Mad-related protein (SMAD) signaling pathway in sea cucumbers (Apostichopus japonicus). The results showed that the A. japonicus in the group with 200 mg/kg vitamin E exhibited significantly higher growth rates, hydroxyproline (Hyp) and type III collagen contents, and superoxide dismutase (SOD) activity, as well as the upregulation of genes related to Tenascin, SMAD1, and TGF-β. Additionally, the A. japonicus in the group with 100 mg/kg vitamin E exhibited significantly higher body-wall indexes, denser collagen arrangements, improved texture quality, higher activities of glutathione peroxidase (GSH-Px) and peroxidase (POD), as well as the upregulation of genes related to collagen type I alpha 2 chain (COL1A2), collagen type III alpha 1 chain (COL3A1), and Sp-Smad2/3 (SMAD2/3). In contrast, the A. japonicus in the group with 400 mg/kg vitamin E showed a decrease in the growth rates, reduced Hyp contents, increased type I collagen contents, collagen fiber aggregation and a harder texture, along with the downregulation of genes related to the TGF-β/SMAD signaling pathway. Furthermore, the A. japonicus in the group with 400 mg/kg exhibited oxidative stress, reflected by the lower activities of SOD, GSH-Px, and POD. These results indicated that A. japonicus fed diets with the addition of 100-200 mg/kg vitamin E had improved collagen retention and texture quality by increasing the activities of antioxidant enzymes and the expressions of genes in the TGF-β/SMAD signaling pathway. However, the excessive addition of vitamin E (400 mg/kg) induced oxidative stress, which could increase the collagen degradation and fibrosis and pose a threat to the growth and texture quality of A. japonicus.

MFN2 regulates progesterone biosynthesis and proliferation of granulosa cells during follicle selection in hens

Follicle selection in hens refers to a biological process that only one small yellow follicle (SYF) is selected daily or near-daily for following hierarchical development (from F5/F6 to F1) until ovulation. MFN2 is a kind of GTPases located on the mitochondrial outer membrane, which plays a crucial role in mitochondrial fusion. This study aimed to elucidate the role of MFN2 in proliferation and progesterone biosynthesis of granulosa cells (GCs) during follicle selection in hens. The results showed that GCs began to produce progesterone (P4) after follicle selection, accompanied with changes from multi-layer with flat cells to single layer with cubic cells. MFN2 was detected in GCs of follicles from SYF to F1. After follicle selection, the expression level of MFN2 in GCs upregulated significantly, accompanied with increases in P4 biosynthesis, ATP production, mitochondrial DNA (mtDNA) copy numbers of granulosa cells. FSH (80 ng/mL) facilitated the effects of P4 biosynthesis and secretion, ATP production, mtDNA copy numbers, cell proliferation and the MFN2 transcription of granulosa cells from F5 (F5G) in vitro. However, FSH treatment did not promote P4 secretion in granulosa cells from SYF (SYFG) in vitro. Meanwhile, we observed that change fold of MFN2 transcription, ATP production, mtDNA copy numbers and cell proliferation rate in F5G after treatment with FSH were greater than those in SYFG. Furthermore, expression levels of MFN2 protein and messenger RNA in F5G were significantly higher than those in SYFG after treatment with FSH. P4 biosynthesis, ATP production, mtDNA copy numbers as well as cell proliferation reduced significantly in F5G with MFN2 knockdown. Oppositely, P4 biosynthesis, ATP production, mtDNA copy numbers and cell proliferation increased significantly in SYFG after the overexpression of MFN2. Our results suggest that the upregulation of MFN2 may be involved in the initiation of P4 biosynthesis, and promotion of GCs proliferation during follicle selection.

Dynamic Expression Profile of Follicles at Different Stages in High- and Low-Production Laying Hens

Improving the efficiency of hens and extending the egg-laying cycle require maintaining high egg production in the later stages. The ovarian follicles, as the primary functional units for ovarian development and oocyte maturation, play a crucial role in regulating the continuous ovulation of hens. The egg production rate of laying hens is mostly affected by proper follicle growth and ovulation in the ovaries. The objective of this study was to identify the key genes and signaling pathways involved in the development of ovarian follicles in Taihang hens through transcriptome screening. In this study, RNA sequencing was used to compare and analyze the transcriptomes of ovarian follicles at four developmental stages: small white follicles (SWF), small yellow follicles (SYF), F5 follicles, and F2 follicles, from two groups: the high continual production group (H-Group) and the low continual production group (L-Group). A total of 24 cDNA libraries were constructed, and significant differential expression of 96, 199, 591, and 314 mRNAs was detected in the SWF, SYF, F5, and F2 follicles of the H and L groups, respectively. Based on the results of GO and KEGG enrichment analyses, each stage of follicle growth possesses distinct molecular genetic features, which have important effects on follicle development and significantly promote the formation of continuous production traits through the biosynthesis of steroid hormones, cytokine-cytokine receptor interaction, and neuroactive ligand-receptor interaction. Additionally, through STEM analysis, we identified 59 DEGs, including ZP4, KCNH1, IGFs, HMGA2, and CDH1, potentially associated with follicular development within four significant modules. This study represents the first transcriptome investigation of follicles in hens with high and low egg-producing characteristics at four crucial developmental stages. These findings provide important molecular evidence for understanding the regulation of follicular development and its variations.

PRP significantly promotes the adhesion and migration of vascular smooth muscle cells on stent material

BACKGROUND

The adhesion and survival state of cells on scaffold material is a major problem in tissue-engineered blood vessel (TEBV) culture. Platelet-rich plasma (PRP) contains a large amount of biologically active factors and fibrin, which is expected to play an important role in TEBV culture.

PURPOSE

To combine PRP with cells and scaffold material to promote cell adhesion and biological activity on the scaffold material.

METHODS

The adhesion status and migration of SMCs under the optimal concentration suitable for SMC growth and the optimal concentration of PRP were examined by scanning electron microscopy, HE staining, CCK-8 assays, qPCR, WB, and other experimental methods and compared with those under the conventional culture (20% FBS); finally, the effect of PRP on the deposition of ECM in vascular tissue engineering culture was verified by three-dimensional culture.

RESULTS

PRP at 20% is a suitable concentration for SMCs. Compared with the control group, the 20% PRP group had better migration, and the number of SMC adhesions was significantly higher than that of the control group. In addition, collagen deposition in the experimental group was significantly higher than that in the control group.

CONCLUSION

PRP (20%) can promote SMC adhesion, migration, and collagen deposition on the scaffold material.

A novel trans-acting lncRNA of ACTG1 that induces the remodeling of ovarian follicles

Previous studies have implicated the attractive role of long noncoding RNAs (lncRNAs) in the remodeling of mammalian tissues. The migration of granulosa cells (GCs), which are the main supporting cells in ovarian follicles, stimulates the follicular remodeling. Here, with the cultured GCs as the follicular model, the actin gamma 1 (ACTG1) was observed to significantly promote the migration and proliferation while inhibit the apoptosis of GCs, suggesting that ACTG1 was required for ovarian remodeling. Moreover, we identified the trans-regulatory lncRNA of ACTG1 (TRLA), which was epigenetically targeted by histone H3 lysine 4 acetylation (H3K4ac). Mechanistically, the 2-375 nt of TRLA bound to ACTG1's mRNA to increase the expression of ACTG1. Furthermore, TRLA facilitated the migration and proliferation while inhibited the apoptosis of GCs, thereby accelerating follicular remodeling. Besides, TRLA acted as a ceRNA for miR-26a to increase the expression of high-mobility group AT-hook 1 (HMGA1). Collectively, TRLA induces the remodeling of ovarian follicles via complementary to ACTG1's mRNA and regulating miR-26a/HMGA1 axis in GCs. These observations revealed a novel and promising trans-acting lncRNA mechanism mediated by H3K4ac, and TRLA might be a new target to restore follicular remodeling and development.

Iron overload triggering ECM-mediated Hippo/YAP pathway in follicle development: a hypothetical model endowed with therapeutic implications

Disruption of iron homeostasis plays a negative role in follicle development. The dynamic changes in follicle growth are dependent on Hippo/YAP signaling and mechanical forces. However, little is known about the liaison between iron overload and the Hippo/YAP signalling pathway in term of folliculogenesis. Here, based on the available evidence, we established a hypothesized model linking excessive iron, extracellular matrix (ECM), transforming growth factor-β (TGF-β) and Hippo/Yes-associated protein (YAP) signal regarding follicle development. Hypothetically, the TGF-β signal and iron overload may play a synergistic role in ECM production via YAP. We speculate that the dynamic homeostasis of follicular iron interacts with YAP, increasing the risk of ovarian reserve loss and may enhance the sensitivity of follicles to accumulated iron. Hence, therapeutic interventions targeting iron metabolism disorders, and Hippo/YAP signal may alter the consequences of the impaired developmental process based on our hypothesis, which provides potential targets and inspiration for further drug discovery and development applied to clinical treatment.

miR-199-3p suppresses cellular migration and viability and promotes progesterone production in goose ovarian follicles before selection through regulating ITGB8 and other ECM-related genes

1. The extracellular matrix (ECM) constitutes the basal lamina and the area between follicular cells. Remodelling the ECM is believed to be a key event in follicular development, especially during selection, and plays an important role in cell migration, survival, and steroidogenesis. miR-199-3p is differentially expressed in the goose granulosa layer during follicular selection and is reported to play a primary role in inhibiting cell migration and invasion. Nevertheless, the effect of miR-199-3p on ovarian follicles and its role in follicular cellular migration is not understood.2. In this study, qRT-PCR assays revealed that miR-199-3p was differentially expressed in the granulosa layer from goose ovarian follicles before and after follicular selection. Additionally, miR-199-3p overexpression in cultured granulosa cells (GCs) from goose pre-hierarchical follicles significantly suppressed cell viability and migration. It elevated the concentration of progesterone and the expression of key progesterone production genes. Furthermore, miR-199-3p overexpression in the GCs of goose pre-hierarchical follicles inhibited the expression of ECM-related genes (ITGB8, MMP9 and MMP15) yet promoted the expression of another two ECM-related genes (COL4A1 and LAMA1). Finally, dual-fluorescence reporter experiments on 293T cells established the direct targeting of ECM gene ITGB8 by miR-199-3p.3. In conclusion, miR-199-3p may participate in granulosa cell migration, viability, and steroidogenesis in goose ovarian follicles before selection by modulating ITGB8 and other ECM-related genes.

Interacting Networks of the Hypothalamic-Pituitary-Ovarian Axis Regulate Layer Hens Performance

Egg production is a vital biological and economic trait for poultry breeding. The 'hypothalamic-pituitary-ovarian (HPO) axis' determines the egg production, which affects the layer hens industry income. At the organism level, the HPO axis is influenced by the factors related to metabolic and nutritional status, environment, and genetics, whereas at the cellular and molecular levels, the HPO axis is influenced by the factors related to endocrine and metabolic regulation, cytokines, key genes, signaling pathways, post-transcriptional processing, and epigenetic modifications. MiRNAs and lncRNAs play a critical role in follicle selection and development, atresia, and ovulation in layer hens; in particular, miRNA is known to affect the development and atresia of follicles by regulating apoptosis and autophagy of granulosa cells. The current review elaborates on the regulation of the HPO axis and its role in the laying performance of hens at the organism, cellular, and molecular levels. In addition, this review provides an overview of the interactive network regulation mechanism of the HPO axis in layer hens, as well as comprehensive knowledge for successfully utilizing their genetic resources.

Protective Effect of Grape Seed Proanthocyanidins on Oxidative Damage of Chicken Follicular Granulosa Cells by Inhibiting FoxO1-Mediated Autophagy

A significant decrease in poultry egg production occurs due to ovarian aging and autophagy is one of the important factors of ovarian aging that is induced predominantly by oxidative stress. Increasing evidence showed potential roles of plant-derived grape seed proanthocyanidin (GSPs) in protecting ovarian granulosa cells (GCs) from oxidative damage, although the underlying mechanism is still unclear. Here we investigated the possible functions of autophagy involved in the preventive effect of GSPs on oxidative stress in the GCs of ovarian hierarchical follicles of laying chickens. The results showed that increased autophagy was observed in the aging hens (580-day-old, D580) compared with the peak-lay hens (D280). Treatment of GSPs significantly restored the elevated autophagy and decreased viability of cultured D280 chicken GCs that were elicited by hydrogen peroxide. GSPs also suppressed the increased autophagy in the natural aging hens. Similar to the effect of GSPs on GC viability, inhibition of autophagy also showed a protective effect on the decreased viability of GCs under oxidative damage. However, GSPs were not able to provide further protection in GCs that were pretreated with 3-methyladenine (an autophagy inhibitor). In addition to its promoting action on antioxidant capacity, treatment with GSPs increased survival of GCs from autophagy that was caused by oxidative stress through the FoxO1-related pathway. Inhibition of FoxO1 or activation of PI3K-Akt pathway by GSPs increased the confrontation of GCs to oxidative damage and decreased autophagy in GCs. In addition, activation of the SIRT1 signal inhibited the GCs autophagy that was caused by oxidative stress via GSPs-induced deacetylation of FoxO1. These results revealed a new mechanism of GSPs against oxidative stress of GCs via inhibiting FoxO1, which was probably a possible target for alleviating ovarian aging in laying poultry.