Leukemia inhibitory factor prevents chicken follicular atresia through PI3K/AKT and Stat3 signaling pathways

Oxidative phosphorylation decline and mitochondrial dynamics disequilibrium are involved in chicken large white follicle atresia

In domestic hens, the atresia of large white follicles (LWFs) directly affects the number of follicles that enter the hierarchical development and ovulation. Figuring out factors responsible for LWFs atresia is helpful to improve egg production of hens. At the LWF stage, yellow yolk begins to be deposited into the follicles via receptor mediated endocytosis, which requires large amounts of ATP. Mitochondrial oxidative phosphorylation (OXPHOS) is the primary source of ATP for follicular development. However, it is not clear whether the OXPHOS is changed along LWFs atresia. In this study, firstly, differences in morphological appearance, histology, cell proliferation, apoptosis, OXPHOS and mitochondrial dynamics between LWFs and atretic large white follicles (ALWFs) in hens at the peak laying stage (35W) were determined to elucidate whether OXPHOS changes in ALWFs. Then, these differences of LWFs between the peak laying hens (35W-LWFs) and the late laying hens (70W-LWFs) were detected to confirm whether OXPHOS changes during LWFs atresia. The results showed that ALWFs exhibited a wrinkled surface with several hemorrhage spots, and numerous intercellular vacuoles, as well as severe nuclear pyknosis. Compared to LWFs, a higher cell apoptosis rate and a lower proliferation rate were observed in ALWFs. In ALWFs, OXPHOS declined as manifested by reductions in ATP levels, ATP synthetase abundance, NAD+, NADH and NAD+/NADH ratio, and mRNA levels of genes associated with OXPHOS complexes I-V. Meanwhile, mitochondrial dynamics disequilibrium was detected in ALWFs as the expression levels of proteins and genes related to mitochondrial fusion (MFN1, MFN2, and OPA1) decreased, while the expression levels of proteins and genes related to mitochondrial fission (DRP1 and FIS1) increased. Further, compared to 35W-LWFs, 70W-LWFs showed a histology resembling to ALWFs, manifested as a slightly loosen structure of granulosa layers, and a lower cell proliferation rate. Moreover, both lower OXPHOS and impaired mitochondrial dynamics were detected in 70W-LWFs. In conclusion, our results indicated that OXPHOS decline and mitochondrial dynamics disequilibrium are involved in LWFs atresia in laying hens.

Chicken ovarian follicular atresia: interaction network at organic, cellular, and molecular levels

Most of follicles undergo a degenerative process called follicular atresia. This process directly affects the egg production of laying hens and is regulated by external and internal factors. External factors primarily include nutrition and environmental factors. In follicular atresia, internal factors are predominantly regulated at 3 levels; organic, cellular and molecular levels. At the organic level, the hypothalamic-pituitary-ovary (HPO) axis plays an essential role in controlling follicular development. At the cellular level, gonadotropins and cytokines, as well as estrogens, bind to their receptors and activate different signaling pathways, thereby suppressing follicular atresia. By contrast, oxidative stress induces follicular atresia by increasing ROS levels. At the molecular level, granulosa cell (GC) apoptosis is not the only factor triggering follicular atresia. Autophagy is also known to give rise to atresia. Epigenetics also plays a pivotal role in regulating gene expression in processes that seem to be related to follicular atresia, such as apoptosis, autophagy, proliferation, and steroidogenesis. Among these processes, the miRNA regulation mechanism is well-studied. The current review focuses on factors that regulate follicular atresia at organic, cellular and molecular levels and evaluates the interaction network among these levels. Additionally, this review summarizes atretic follicle characteristics, in vitro modeling methods, and factors preventing follicular atresia in laying hens.

Vitrified turkey ovarian tissue cultured and assessed through gene expression patterns: A potential screening tool

Biobanking of turkey ovarian tissue has the potential to play a crucial part in preserving female genetics. To date, ovarian tissue has only been vitrified using a standard protocol, with immediate analyses after warming, therefore, long-term cryoinjury is unknown. Long-term cryoinjury was investigated here by in-ovo culturing, fresh (non-vitrified), a purposefully suboptimal poor vitrification (PV), and the standard vitrified (StV) protocol. Assessments were performed via cellular morphological changes and mRNA gene expression differences, immediately (day 0) or after 2, 4, or 6 days of in-ovo culturing. On day 0, the mRNA levels of heat-shock protein A2 (HSPA2) were lowest in the fresh tissue, and increased 5-fold in the StV treatment, and 18-fold in the PV treatment. Whereas, by day 6, growth determining factor 9 (GDF9) mRNA levels within the fresh tissue were over 3-fold and 21-fold higher than StV and PV treatments, respectively. After 6 days of in-ovo culture the follicle density was highest in the fresh ovarian tissue (4701 ± 950 #/mm3), followed by the StV (1601 ± 300 #/mm3), with PV having the lowest density (172 ± 145 #/mm3). This shows that although the density of follicles was higher in StV versus PV, a considerable number (∼65 %) were lost compared to the fresh treatment. Additionally, the HSPA2 expression could be an early screening tool, whereas GDF9 expression could be a late screening tool, used to assess turkey ovarian tissue vitrification protocols. We conclude that the StV protocol should be further optimized to try and improve follicle numbers post-warming.

LIF regulates the expression of miR-27a-3p and HOXA10 in bovine endometrial epithelial cells via STAT3 pathway

LIF is crucial in regulating embryo implantation, while HOXA10 is a marker gene for uterine receptivity. However, the specific mechanism of LIF regulating HOXA10 during cow embryo implantation has not been fully understood. To address this knowledge gap, the experiment involved treating bovine endometrial epithelial cells (BEECs) with LIF to investigate the relationship between LIF, miRNA, and HOXA10. The experimental findings revealed that applying LIF resulted in a substantial increase in the proliferation of endometrial epithelial cells. Moreover, the expressions of PI3K, AKT, HOXA10, CDK4, cyclinD1, and cyclinE1 were significantly elevated. Conversely, the expression of p21Cipl was significantly reduced. In the group that received a combination of LIF and a STAT3 inhibitor, the expression of PI3K/AKT remained significantly increased, but there was no significant change in the expression of HOXA10. When miRNA-27a-3p was overexpressed, it resulted in a decrease in both the RNA and protein expression of HOXA10. Conversely, inhibiting miRNA-27a-3p increased the RNA and protein expression of HOXA10. In the presence of LIF treatment, the expression of miRNA-27a-3p was reduced, while the expression of HOXA10 was increased. However, when LIF and a STAT3 inhibitor were combined, there was no significant change in the expression of miRNA-27a-3p or HOXA10. Consequently, LIF facilitated cell proliferation by activating the PI3K/AKT pathway. LIF controlled the expression of miRNA-27a-3p and HOXA10 in endometrial epithelial cells through STAT3, with miRNA-27a-3p negatively regulating the expression of HOXA10.

Bioinformatics and integrated pharmacology network to identify the therapeutic targets and potential molecular mechanism of alpha-lipoic acid on primary ovarian insufficiency

Women experiencing primary ovarian insufficiency (POI) are more likely to experience infertility, and its incidence is increasing worldwide annually. Recently, the role of alpha-lipoic acid (ALA) in the treatment of POI has been reported. However, details of the potential pharmacological targets and related molecular pathways of ALA remain unclear and need to be elucidated. Thus, this study aims to elucidate the potential therapeutic target and related molecular mechanism of ALA on POI. First, the potential targets of POI and ALA-related targets were downloaded from online public databases. Subsequently, the overlapped target genes between POI and ALA were acquired, and gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG) analysis, protein-protein interaction (PPI) networks were performed and constructed. Finally, molecular docking was performed to verify protein-to-protein effect. A total of 152 potential therapeutic targets were identified. The biological processes of the intersecting targets were mainly involved in the cellular response to peptides, response to xenobiotic stimuli, and response to peptide hormones. The highly enriched pathways were the cAMP, PI3K/AKT, estrogen, progesterone mediated oocyte maturation, and apoptosis signaling pathways. The top 10 hub targets for ALA in the treatment of POI were STAT3, STAT1, CASP3, MTOR, PTGS2, CASP8, HSP90AA1, PIK3CA, MAPK1, and ESR1. The binding between ALA and all top hub targets were verified using the molecular docking analysis. In summary, using the systematic integrated pharmacology network and bioinformatics analysis, this study illustrated that ALA participates in the treatment of POI via multiple targets and multiple pathways mechanisms.

Leukemia inhibitory factor's effect on the growth and survival of sheep's follicles of ovarian tissue during vitrification

One of the experimental programs for fertility protection in women includes protective cryopreservation. Vitroficasion of ovarian tissue is one of the protective cryopreservation methods that use high concentrations of antifreeze and faster cooling. To reduce its complications, LIF (Leukemia inhibitory factor) was used as a pretreatment in this study. In this study, the ovaries were randomly divided into 8 groups. In NCN (without pretreatment and LIF in culture media), NCP (without pretreatment and with LIF in culture media), PCP (with pretreatment and LIF in culture media), and PCN (with pretreatment and without LIF in culture media) groups, vitrification and reversal were not performed. In the groups NVN (without pretreatment and LIF in culture media), NVP (without pretreatment and with LIF in culture media) PV, PVP (with pretreatment and LIF in culture media), and PVN (with pretreatment and without LIF in culture medium) groups, vitrification and tissue reversal were performed. All groups were cultured and histological, cellular, and molecular evaluations were performed. The results of the present study showed that LIF in the culture medium reduced the number of abnormal, primordial, primary, and secondary follicles, and DNA breakage compared to the group without LIF (P < 0.05) and increases the growth of follicles and expression of GDF9, BMP, AMH, KITLG genes (P < 0.05). The use of LIF pretreatment before vitrification and melting of sheep ovary tissue in its culture medium reduces the damage caused by it and increases the growth and development of ovarian follicles while maintaining their function.

Melatonin suppresses serum starvation-induced autophagy of ovarian granulosa cells in premature ovarian insufficiency

OBJECTIVES

Premature ovarian insufficiency (POI) refers to the decline and cessation of ovarian functions in women under 40 years of age. Melatonin (MT) acts as a protective for the ovary. This study elucidated the role of MT in autophagy of granulosa cells (GCs) in POI via modulating the phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway.

METHODS

The expression levels of microRNA (miR)-15a-5p, signal transducer and activator of transcription 3 (Stat3), and relevant hormones in the clinically collected serum samples of POI patients and healthy controls were examined. Human ovarian granulosa-like tumor cells (KGN) underwent serum starvation (SS) treatment to induce POI cell models and then received MT treatment. The expression levels of miR-15a-5p, Stat3, p-PI3K/PI3K, p-Akt/Akt, and p-mTOR/mTOR in KGN cells were tested via quantitative real-time polymerase chain reaction and Western blotting. KGN cell viability was assessed by MTT assay and the protein levels of autophagy-related markers Beclin-1, microtubule-associated protein light chain 3 II/I, and p62 were detected by Western blotting. The binding relation between miR-15a-5p and Stat3 was verified via the dual-luciferase reporter gene assay. Functional rescue experiments were performed to probe the underlying role of miR-15a-5p/Stat3/the PI3K-Akt-mTOR pathway in KGN cell autophagy.

RESULTS

miR-15a-5p was increased whilst Stat3 was decreased in the serum of POI patients and SS-induced KGN cells. MT inhibited miR-15a-5p and Stat3, activated the PI3K-Akt-mTOR pathway, and repressed cell autophagy in SS-induced KGN cells. miR-15a-5p targeted and repressed Stat3 expression. Upregulation of miR-15a-5p or downregulation of Stat3 or the PI3K-Akt-mTOR pathway promoted KGN cell autophagy.

CONCLUSION

MT suppressed miR-15a-5p and activated Stat3 and the PI3K-Akt-mTOR pathway, finally impeding SS-induced autophagy of GCs.

Follicle-Stimulating Hormone Alleviates Ovarian Aging by Modulating Mitophagy- and Glycophagy-Based Energy Metabolism in Hens

As a predominant hormone in the reproductive axis, follicle-stimulating hormone (FSH) is known as the primary surviving factor for follicular growth. In this study, the alleviating effect of FSH on aging chicken granulosa cells (GCs) was investigated. Results showed that FSH activated mitophagy and relieved mitochondrial edema in D-gal-induced senescent GCs, which was evidenced by an increased number of mitophagosomes as well as increased mitochondria-light chain 3 (LC3) colocalization. Mitophagy activation was accompanied by the activation of the AMP-activated protein kinase (AMPK) signaling pathway. Furthermore, upregulated glycophagy was demonstrated by an increased interaction of starch-binding domain protein 1 (STBD1) with GABA type A receptor-associated protein-like 1 (GABARAPL1) in D-gal-induced senescent GCs. FSH treatment further promoted glycophagy, accompanied by PI3K/AKT activation. PI3K inhibitor LY294002 and AKT inhibitor GSK690693 attenuated the effect of FSH on glycophagy and glycolysis. The inhibition of FSH-mediated autophagy attenuated the protective effect of FSH on naturally aging GC proliferation and glycolysis. The simultaneous blockage of PI3K/AKT and AMPK signaling also abolished the positive effect of FSH on naturally senescent ovarian energy regulation. These data reveal that FSH prevents chicken ovarian aging by modulating glycophagy- and mitophagy-based energy metabolism through the PI3K/AKT and AMPK pathways.

The ILEI/LIFR complex induces EMT via the Akt and ERK pathways in renal interstitial fibrosis

BACKGROUND

Chronic kidney disease (CKD) is characterized by high morbidity and mortality and is difficult to cure. Renal interstitial fibrosis (RIF) is a major determinant of, and commonly occurs within, CKD progression. Epithelial mesenchymal transition (EMT) has been identified as a crucial process in triggering renal interstitial fibrosis (RIF). Interleukin-like EMT inducer (ILEI) is an important promotor of EMT; this study aims to elucidate the mechanisms involved.

METHODS

Male C57BL6/J mouse were randomly divided into 6 groups: sham (n = 10), sham with negative control (NC) shRNA (sham + NC, n = 10), sham with ILEI shRNA (sham + shILEI, n = 10), unilateral ureteral obstruction (UUO, n = 10), UUO with NC (UUO + NC, n = 10) and UUO with ILEI shRNA (UUO + shILEI, n = 10). Hematoxylin and eosin (H&E), Masson, and immunohistochemical (IHC) staining and western blotting (WB) were performed on murine kidney tissue to identify the function and mechanism of ILEI in RIF. In vitro, ILEI was overexpressed to induce EMT in HK2 cells and analyzed via transwell, WB, real-time PCR, and co-immunoprecipitation. Finally, tissue from 12 pediatric CKD patients (seven with RIF and five without RIF) were studied with H&E, Masson, and IHC staining.

RESULTS

Our in vitro model revealed that ILEI facilitates RIF in the UUO model via the Akt and ERK pathways. Further experiments in vivo and in vitro revealed that ILEI promotes renal tubular EMT by binding and activating leukemia inhibitory factor receptor (LIFR), in which phosphorylation of Akt and ERK is involved. We further find markedly increased expression levels of ILEI and LIFR in kidneys from pediatric CKD patients with RIF.

CONCLUSION

Our results indicate that ILEI may be a useful biomarker for renal fibrosis and a potential therapeutic target for modulating RIF.