miR-122-5p regulates proliferation and apoptosis of chicken granulosa cells of hierarchal follicles by targeting MAPK3

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.

Pituitary-derived small extracellular vesicles promote liver repair by its cargo miR-143-3p

The small Extracellular vesicles (sEV) has been recognized to be significant for intercellular communication due to their ability to transfer important cellular cargoes like miRNAs through circulation. The pituitary gland has not been clearly known about the role of its secreted sEV under normal physiological conditions. And Liver disease is a global public health burden. The present study is the first to investigate the effect of pituitary sEV on the liver. Sequencing and qRT-PCR revealed miR-143-3p is one of the richest in the pituitary sEV. MiR-143 Knockout (KO) mice resulted in a remarkable decrease in insulin-like growth factor 1 (IGF-1) levels and a significant increase in insulin-like growth factor binding protein 5 (IGFBP5) levels along with a reduction in liver primary cell growth. More importantly, compared with miR-143-KO-sEV, WT-sEV possesses a more robust capacity to improve miR-143 KO mice liver repair through the Wnt/β-catenin pathway after an acute injury caused by carbon tetrachloride (CCl4). Our results indicate that pituitary-derived sEV promotes hepatocyte proliferation and liver repair by its cargo miR-143-3p and provides new insight into the regulation mechanism of the pituitary-liver axis, and open a new window for endocrine regulation by using sEV.

microRNA transcriptome analysis of granulosa cells predicts that the Notch and insulin pathways affect follicular development in chickens

MicroRNAs (miRNAs) have been documented to play critical roles in chicken reproduction. Granulosa cell (GC) development of the follicle is closely related to hierarchical follicle ordering, making it an important factor in determining laying performance. Thus, it is meaningful to mine follicular development-related miRNAs. To identify regulatory miRNAs and the biological mechanisms by which they control follicular development, we conducted small RNA sequencing of GCs isolated from prehierarchical follicles named small yellow follicle (SYFG), the smallest hierarchical follicle (F6G), and the largest hierarchical follicle (F1G). A total of 99, 196, and 110 differentially expressed miRNAs (DEMs) were identified in SYFG.vs.F6G, SYFG.vs.F1G, and F6G.vs.F1G, respectively. Of these, 22 miRNAs, including miR-223, miR-103a, miR-449c-3p, and miR-203a, were ubiquitously identified as DEMs in three stages. Target gene prediction suggested that these miRNAs are associated with the MAPK, TGF-β, and Wnt signaling pathways, which are all associated with follicular development. The Notch and insulin signaling pathways were commonly enriched in all three comparisons. RT-qPCR analysis further indicated that the expression levels of PSEN2, which encodes an essential factor regulating Notch and insulin signaling, was significantly changed in SYFG, F6G, and F1G. The current study provides basic data and offers a new foundation for further exploration of the roles of miRNAs in follicular development in chickens.

DCLRE1A Contributes to DNA Damage Repair and Apoptosis in Age-Related Cataracts by Regulating the lncRNA/miRNA/mRNA Axis

PURPOSE

Age-related cataract (ARC) is associated with the deregulation of transcription and defects in DNA repair in lens epithelial cells (LECs). DCLRE1A acted in DNA interstrand cross-links pathway to improve DNA replication and transcription. The aim of this study was to examined the further regulatory effect on DCLRE1A in the lncRNA-miRNA-mRNA network using a cell model of DCLRE1A overexpression (OE-DCLRE1A) in LECs.

METHODS

The expression level of DCLRE1A in ARC tissues and SRA01/04 cells after H2O2 treatment was measured as protein and mRNA by qRT-PCR and Western Blot(WB). CCK8, and TUNEL assays detected the change in cell viability and apoptosis, respectively. Furthermore, Immunofluorescence assays detect the expression of DNA damaged and repair marker proteins after OE-DCLRE1A. The global expression profiles of lncRNAs, miRNAs, and mRNAs were determined using high-throughput sequencing. KEGG and GO enrichment analysis disclose the possible function of differentially expressed (DE) lncRNA, miRNA, and mRNA.

RESULTS

The protein and mRNA of DCLRE1A were decreased in the anterior capsule of ARC and SRA01/04 cells treated by H2O2. OE-DCLRE1A improved damaged-DNA repair and enhanced cell viability against apoptosis after H2O2 treatment. Furthermore, we demonstrated the DE-molecules between the OE-DCLRE1A and control groups including 595 DE-lncRNAs, 221 DE-miRNAs, and 4718 DE-mRNAs. Next, bioinformatics analysis not only found that the DE-mRNAs are mainly involved in DNA repair-related signaling pathways after OE-DCLRE1A, but also screened two lncRNA-miRNA-mRNA networks focusing on DNA damage activated by OE-DCLRE1A, which involved 2 lncRNAs, 2 miRNAs, and 53 mRNAs.

CONCLUSION

We revealed that DCLRE1A activated the lncRNA/miRNA/DNA-repair network to take part in DNA repair processes, which not only represents a new regulatory mechanism employed by DCLRE1A but also uncovers the screening lncRNA may hold potential therapeutic values in ARC formation. However, these conclusions will need to be confirmed by future studies in vitro and in vivo models.

Lipid Deposition and Progesterone Synthesis Are Increased by miR-181b-5p through RAP1B/ERK1/2 Pathway in Chicken Granulosa Cells

Steroid hormones secreted by granulosa cells are essential for maintaining normal development of chicken follicles. Our previous sequencing data indicated that miR-181b-5p and RAS-related protein 1B (RAP1B) appeared to function in chicken granulosa cells, which was further explored in this study. The results suggested that miR-181b-5p facilitated the aggregation of lipid droplets and the synthesis of progesterone. In contrast, RAP1B astricted lipid deposition and progesterone secretion. Cotransfection of the RAP1B overexpression vector with miR-181b-5p mimic eliminated the promoting effect of miR-181b-5p. Dual-luciferase reporter assay confirmed that miR-181b-5p bound directly to the 3' untranslated region (3' UTR) of RAP1B. We also found that miR-181b-5p and RAP1B reduced and enhanced the phosphorylation levels of extracellular signal-regulated kinases 1 and 2 (ERK1/2), respectively. The application of ERK1/2 activators and inhibitors demonstrated that ERK1/2 is a negative regulator of lipid deposition and progesterone synthesis. In conclusion, we revealed that miR-181b-5p accelerated lipid deposition and progesterone synthesis through the RAP1B/ERK1/2 pathway in chicken granulosa cells. miR-181b-5p and RAP1B may serve as new biomarkers in breeding to improve chicken reproductive performance and prevent ovary-related diseases.

Intravitreal Administration of Retinal Organoids-Derived Exosomes Alleviates Photoreceptor Degeneration in Royal College of Surgeons Rats by Targeting the Mitogen-Activated Protein Kinase Pathway

Increasing evidence suggests that exosomes are involved in retinal cell degeneration, including their insufficient release; hence, they have become important indicators of retinopathies. The exosomal microRNA (miRNA), in particular, play important roles in regulating ocular and retinal cell functions, including photoreceptor maturation, maintenance, and visual function. Here, we generated retinal organoids (ROs) from human induced pluripotent stem cells that differentiated in a conditioned medium for 60 days, after which exosomes were extracted from ROs (Exo-ROs). Subsequently, we intravitreally injected the Exo-RO solution into the eyes of the Royal College of Surgeons (RCS) rats. Intravitreal Exo-RO administration reduced photoreceptor apoptosis, prevented outer nuclear layer thinning, and preserved visual function in RCS rats. RNA sequencing and miRNA profiling showed that exosomal miRNAs are mainly involved in the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, the expression of MAPK-related genes and proteins was significantly decreased in the Exo-RO-treated group. These results suggest that Exo-ROs may be a potentially novel strategy for delaying retinal degeneration by targeting the MAPK signaling pathway.

RNA-Seq-based discovery of genetic variants and allele-specific expression of two layer lines and broiler chicken

Recent advances in the selective breeding of broilers and layers have made poultry production one of the fastest-growing industries. In this study, a transcriptome variant calling approach from RNA-seq data was used to determine population diversity between broilers and layers. In total, 200 individuals were analyzed from three different chicken populations (Lohmann Brown (LB), n = 90), Lohmann Selected Leghorn (LSL, n = 89), and Broiler (BR, n = 21). The raw RNA-sequencing reads were pre-processed, quality control checked, mapped to the reference genome, and made compatible with Genome Analysis ToolKit for variant detection. Subsequently, pairwise fixation index (F ST) analysis was performed between broilers and layers. Numerous candidate genes were identified, that were associated with growth, development, metabolism, immunity, and other economically significant traits. Finally, allele-specific expression (ASE) analysis was performed in the gut mucosa of LB and LSL strains at 10, 16, 24, 30, and 60 weeks of age. At different ages, the two-layer strains showed significantly different allele-specific expressions in the gut mucosa, and changes in allelic imbalance were observed across the entire lifespan. Most ASE genes are involved in energy metabolism, including sirtuin signaling pathways, oxidative phosphorylation, and mitochondrial dysfunction. A high number of ASE genes were found during the peak of laying, which were particularly enriched in cholesterol biosynthesis. These findings indicate that genetic architecture as well as biological processes driving particular demands relate to metabolic and nutritional requirements during the laying period shape allelic heterogeneity. These processes are considerably affected by breeding and management, whereby elucidating allele-specific gene regulation is an essential step towards deciphering the genotype to phenotype map or functional diversity between the chicken populations. Additionally, we observed that several genes showing significant allelic imbalance also colocalized with the top 1% of genes identified by the FST approach, suggesting a fixation of genes in cis-regulatory elements.

miR-140-3p promotes follicle granulosa cell proliferation and steroid hormone synthesis via targeting AMH in chickens

Granulosa cells (GCs) are the ovary's most critical cells since they undergo cell differentiation and hormone synthesis changes closely associated with follicle development. While micro RNA 140-3p (miRNA-140-3p) has an apparent cell signaling role, particularly in cell proliferation, its biological role in chicken ovarian follicle growth and development remains elusive. This study explored miR-140-3p's effects on chicken GC proliferation and steroid hormone synthesis. MiR-140-3p dramatically increased GC proliferation, prevented apoptosis, increased progesterone synthesis, and enhanced gene expression related to steroid hormone synthesis. In addition, the anti-Müllerian hormone (AMH) gene was identified as a direct miR-140-3p target. MiR-140-3p abundance correlated negatively with AMH mRNA and protein levels in GCs. Our findings show that miR-140-3p influences chicken GC proliferation and steroid hormone synthesis by suppressing AMH expression.

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.

Prenatal Exposure to Delta-9-tetrahydrocannabinol (THC) Alters the Expression of miR-122-5p and Its Target Igf1r in the Adult Rat Ovary

As cannabis use during pregnancy increases, it is important to understand its effects on the developing fetus. Particularly, the long-term effects of its psychoactive component, delta-9-tetrahydrocannabinol (THC), on the offspring’s reproductive health are not fully understood. This study examined the impact of gestational THC exposure on the miRNA profile in adult rat ovaries and the possible consequences on ovarian health. Prenatal THC exposure resulted in the differential expression of 12 out of 420 evaluated miRNAs. From the differentially expressed miRNAs, miR-122-5p, which is highly conserved among species, was the only upregulated target and had the greatest fold change. The upregulation of miR-122-5p and the downregulation of its target insulin-like growth factor 1 receptor (Igf1r) were confirmed by RT-qPCR. Prenatally THC-exposed ovaries had decreased IGF-1R-positive follicular cells and increased follicular apoptosis. Furthermore, THC decreased Igf1r expression in ovarian explants and granulosa cells after 48 h. As decreased IGF-1R has been associated with diminished ovarian health and fertility, we propose that these THC-induced changes may partially explain the altered ovarian follicle dynamics observed in THC-exposed offspring. Taken together, our data suggests that prenatal THC exposure may impact key pathways in the developing ovary, which could lead to subfertility or premature reproductive senescence.