High-throughput sequencing reveals differential expression of miRNAs in prehierarchal follicles of laying and brooding geese

Ovarian Transcriptome Profile from Egg-Laying Period to Incubation Period of Changshun Green-Shell Laying Hens

Background/Objectives: The Changshun green-shell laying hen with a strong broodiness is a Chinese indigenous chicken breed. Little is known about the mechanisms responsible for the ovary development of Changshun green-shell laying hens from the egg-laying period (LP) to the incubation period (BP). Methods: A total of six hens were selected from LP (n = three) and BP (n = three) at 28 weeks old. The RNA sequencing (RNA-seq) of ovaries from hens in LP and BP groups was performed to identify candidate genes and pathways associated with broodiness. Results: We identified 1650 differently expressed genes (DEGs), including 429 up-regulated and 1221 down-regulated DEGs, in chicken ovaries between LP and BP groups. Gene ontology term (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these DEGs were mainly involved in the pathways related to follicle development in chicken ovaries, including focal adhesion, the MAPK signaling pathway, and the FoxO signaling pathway, and vascular smooth muscle contraction, ECM-receptor interaction, and the GnRH signaling pathway were down-regulated in incubating ovaries. Eight candidate genes (EGFR, VEGFRKDRL, FLT1, KDR, PDGFRA, TEK, KIT and FGFR3) related to angiogenesis, folliculogenesis, steroidogenesis and oogenesis in ovaries were suggested to play important roles in the ovarian development of Changshun hens during the transition from LP to BP. Conclusions: This study identified a range of genes and several pathways that may be involved in regulating the broodiness of Changshun green-shell laying hens. These data are helpful to further enrich our understanding of the mechanism of incubation behaviour in chickens.

Multi-omics analyses reveal that sirtuin 5 promotes the development of pre-recruitment follicles by inhibiting the autophagy-lysosome pathway in chicken granulosa cells

The development of pre-recruitment follicles plays a critical role in determining egg-laying performance in poultry. This study combines proteomic and metabolomic analyses to explore changes in proteins and metabolites, to elucidate key regulatory mechanism involved in chicken pre-recruitment follicular development. Histological examination revealed a significant increase in yolk deposition in small yellow follicles (SYF) compared to small white follicles (SWF). Metabolomics analysis identified significantly enriched differential metabolites (DMs) between SWF and SYF in pathways such as Lysosome, Ferroptosis, Biosynthesis of unsaturated fatty acids, and Tryptophan metabolism. Particularly, Adenosine-5'-Diphosphate (ADP) was downregulated during follicular recruitment and was significantly enriched in the lysosome pathway. Proteomic analyses revealed that differentially expressed proteins (DEPs) in SWF and SYF were enriched in pathways including Lysosome, Glutathione metabolism, Cholesterol metabolism, Arginine and proline metabolism, and amino acid biosynthesis. Among these DEPs, NAD-dependent protein deacetylase sirtuin 5 (SIRT5) was significantly upregulated, while lysosomal-associated membrane protein 1 (LAMP1) was down-regulated during the development of pre-recruitment follicles. SIRT5 was linked to the negative regulation of reactive oxygen species metabolism, whereas LAMP1 was associated with lysosome and autophagy pathways. Further validation experiments demonstrated high expression of SIRT5 in SYF, particularly in granulosa cells (GCs). Silencing SIRT5 in GCs resulted in increased ROS production and upregulated expression of autophagy-related proteins LC3Ⅱ and Beclin1, as well as lysosome markers LAMP1. Conversely, lipid droplet deposition and p62 expression were suppressed. inhibited. Taken together, these findings suggest that SIRT5 upregulation promotes the development of pre-recruitment follicles by inhibiting the autophagy-lysosome pathway in chicken GCs.

The hematopoietic function, histological characteristics, and transcriptome profiling of Wanxi white geese ovary during nesting and late-laying stages

Despite several factors influencing reproduction in geese, but the precise molecular mechanisms of egg cessation are not fully understood. In the present study, the hematopoietic parameters and serum hormone levels in Wanxi white geese were analyzed. RNA-Seq was utilized to identify the differentially expressed mRNAs (DEGs) and lncRNAs (DE lncRNAs) in the ovarian tissues associated with nesting in geese during the late-laying and nesting periods. Triglyceride (TG) and alkaline phosphatase (ALP) levels were higher in late-laying geese, while white blood cell (WBC), neutrophil (NEU), hemoglobin (HGB), and hematocrit (HCT) levels were significantly lower in late-laying geese. Serum levels of luteinizing hormone (LH), estrogen (E2), and progesterone (P4) increased significantly during the late-laying period, whereas prolactin (PRL) level was lower in the late-laying period than the nesting period. During the late-laying period, geese had a clear follicular hierarchy, with ovaries exhibiting mature and primary follicles. In the nesting period, the ovaries were degenerated and had many primary follicles without follicular development. Analysis of mRNA-lncRNA expression revealed 1,257 DEGs between the nesting and the late-laying stages, of which 841 were up-regulated and 416 were down-regulated DEGs. A total of 340 DE lncRNAs were identified between the nesting and the late-laying periods, with 113 being up-regulated and 227 down-regulated lncRNAs. DEGs, including TMEM, DRD3, IGFBP7, MAPK13, GnRHR2, HECTD3, KCNU1, OPRD1, and VCAM1, along with DE lncRNAs, including XR_001203613.1, XR_001206155.1, XR_001207759.1, XR_001213571.1 and XR_001214368.1 participate in reproduction in geese. Correlation analysis indicated that the cis-regulation of XR_001213096.1-ITPR3, XR_001203613.1-GALNT15, XR_001206155.1-COL6A3, XR_001207759.1-ANKS1B, and XR_001214368.1-VPS45 participate in the molecular mechanisms underlying nesting in geese. Functional enrichment analysis revealed the DEGs and DE lncRNAs associated with focal adhesion, extracellular matrix (ECM)-receptor interaction, cell adhesion molecules (CAMs), and PI3K-Akt signaling pathways, were responsible for the differences in the ovaries between the nesting and late-laying periods. This study offers valuable information on the roles of genes and lncRNAs, and the mechanisms underlying variations in reproductive performance between the late-laying and nesting periods.

The role of miR-10a-5p in LPS-induced inhibition of progesterone synthesis in goose granulosa cells by down-regulating CYP11A1

The poultry ovary is a preferred target for E. coli and Salmonella infection of tissues, and lipopolysaccharide (LPS) is a critical molecule in infecting the organism and interfering with cell function, invading the ovaries through the cloaca and interfering with progesterone (P4) secretion by follicular granulosa cells (GCs), seriously affecting the health of breeding geese. miRNAs are small, non-coding RNAs with a variety of important regulatory roles. To investigate the mechanism of miR-10a-5p mediated LPS inhibition of progesterone synthesis in goose granulosa cells, Yangzhou geese at peak laying period were selected as experimental animals to verify the expression levels of genes and transcription factors related to progesterone synthesis. In this study, bioinformatic predictions identified miR-10a-5p target gene CYP11A1, and genes and transcription factors related to the sex steroid hormone secretion pathway were screened. We detected that LPS inhibited CYP11A1 expression while increasing miR-10a-5p expression in vivo. Progesterone decreased significantly in goose granulosa cells treatment with 1 μg/mL LPS for 24 h, while progesterone-related genes and regulatory factors were also suppressed. We also determined that the downregulation of miR-10a-5p led to CYP11A1 expression. Overexpression of miR-10a-5p suppressed LPS-induced CYP11A1 expression, resulting in decreased progesterone secretion. Our findings indicated that miR-10a-5p was up-regulated by LPS and inhibited progesterone synthesis by down-regulating CYP11A1. This study provides insight into the molecular mechanisms regulating geese reproduction and ovulation.

Long noncoding RNAs and mRNAs profiling in ovary during laying and broodiness in Taihe Black-Bone Silky Fowls (Gallus gallus Domesticus Brisson)

BACKGROUND

Broodiness significantly impacts poultry egg production, particularly notable in specific breeds such as the black-boned Silky, characterized by pronounced broodiness. An understanding of the alterations in ovarian signaling is essential for elucidating the mechanisms that influence broodiness. However, comparative research on the characteristics of long non-coding RNAs (lncRNAs) in the ovaries of broody chickens (BC) and high egg-laying chickens (GC) remains scant. In this investigation, we employed RNA sequencing to assess the ovarian transcriptomes, which include both lncRNAs and mRNAs, in eight Taihe Black-Bone Silky Fowls (TBsf), categorized into broody and high egg-laying groups. This study aims to provide a clearer understanding of the genetic underpinnings associated with broodiness and egg production.

RESULTS

We have identified a total of 16,444 mRNAs and 18,756 lncRNAs, of which 349 mRNAs and 651 lncRNAs exhibited significantly different expression (DE) between the BC and GC groups. Furthermore, we have identified the cis-regulated and trans-regulated target genes of differentially abundant lncRNA transcripts and have constructed an lncRNA-mRNA trans-regulated interaction network linked to ovarian follicle development. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation analyses have revealed that DE mRNAs and the target genes of DE lncRNAs are associated with pathways including neuroactive ligand-receptor interaction, CCR6 chemokine receptor binding, G-protein coupled receptor binding, cytokine-cytokine receptor interaction, and ECM-receptor interaction.

CONCLUSION

Our research presents a comprehensive compilation of lncRNAs and mRNAs linked to ovarian development. Additionally, it establishes a predictive interaction network involving differentially abundant lncRNAs and differentially expressed genes (DEGs) within TBsf. This significantly contributes to our understanding of the intricate interactions between lncRNAs and genes governing brooding behavior.

Whole transcriptome analysis reveals the key genes and noncoding RNAs related to follicular atresia in broilers

Broodiness, a maternal behavior, is accompanied by the atresia of follicles and the serious degradation of poultry reproductive performance. The comparison of follicles between brooding and laying hens is usually an ideal model for exploring the regulation mechanism of follicle atresia. In this study, we selected three brooding hens and three laying hens to collect their follicles for whole transcriptome sequencing. The results demonstrated different expression patterns between the follicles of brooding hens and laying hens. In the top 10 differentially expressed genes with the highest expression, MMP10 was relatively low expressed in the follicles of brooding hens, but other nine genes were relatively highly expressed, including LRR1, RACK1, SPECC1L, ABHD2, COL6A3, RPS17, ATRN, BIRC6, PGAM1 and SPECC1L. While miR-21-3p, miR-146a-5p, miR-142-5p and miR-1b-3p were highly expressed in the follicles of brooding hen, miR-106-5p, miR-451, miR-183, miR-7, miR-2188-5p and miR-182-5p were lowly expressed in brooding hen. In addition, we identified 124 lncRNAs specifically expressed in the follicles of brooding hens and 147 lncRNAs specifically expressed in the follicles of laying hens. Our results may provide a theoretical basis for further exploration of the molecular mechanism of broodiness in broilers.

Integrated Transcriptome Analysis Reveals the Crucial mRNAs and miRNAs Related to Fecundity in the Hypothalamus of Yunshang Black Goats during the Luteal Phase

A normal estrus cycle is essential for the breeding of goats, and the luteal phase accounts for most of the estrus cycle. The corpus luteum (CL) formed during the luteal phase is a transient endocrine gland that is crucial for the reproductive cycle and pregnancy maintenance, and is controlled by many regulatory factors. However, the molecular mechanism of the hypothalamus effect on the reproductive performance of different litter sizes during the luteal phase of goats has not been elucidated. In this study, RNA-sequencing was used to analyze the mRNA and miRNA expression profiles of the hypothalamic tissues with the high-fecundity goats during the luteal phase (LP-HF) and low-fecundity goats during the luteal phase (LP-LF). The RNA-seq results found that there were 1963 differentially expressed genes (DEGs) (890 up-regulated and 1073 down-regulated). The miRNA-seq identified 57 differentially expressed miRNAs (DEMs), including 11 up-regulated and 46 down-regulated, of which 199 DEGs were predicted to be potential target genes of DEMs. Meanwhile, the functional enrichment analysis identified several mRNA-miRNA pairs involved in the regulation of the hypothalamic activity, such as the common target gene MEA1 of novel-miR-972, novel-miR-125 and novel-miR-403, which can play a certain role as a related gene of the reproductive development in the hypothalamic-pituitary-gonadal (HPG) axis and its regulated network, by regulating the androgen secretion. While another target gene ADIPOR2 of the novel-miR-403, is distributed in the hypothalamus and affects the reproductive system through a central role on the HPG axis and a peripheral role in the gonadal tissue. An annotation analysis of the DE miRNA-mRNA pairs identified targets related to biological processes, such as anion binding (GO:0043168) and small molecule binding (GO: 0036094). Subsequently, the KEGG(Kyoto Encyclopedia of Genes and Genomes) pathways were performed to analyze the miRNA-mRNA pairs with negatively correlated miRNAs. We found that the GnRH signaling pathway (ko04912), the estrogen signaling pathway (ko04915), the Fc gamma R-mediated phagocytosis (ko04666), and the IL-17 signaling pathway (ko04657), etc., were directly and indirectly associated with the reproductive process. These targeting interactions may be closely related to the reproductive performance of goats. The results of this study provide a reference for further research on the molecular regulation mechanism for the high fertility in goats.

Differential expression and functional analysis of circRNA in the ovaries of Yili geese at different egg-laying stages

BACKGROUND

Ovarian development is regulated by genes that are expressed dynamically and stage-specifically. Circular RNA (circRNA) has been proven to play a significant role in the regulation of animal reproduction.

OBJECTIVE

Studying the expression characteristics of circRNAs in goose ovaries at various egg-laying stages can provide a reference for the molecular regulation mechanism of ovary development in geese that is mediated by circRNAs.

METHODS

In this study, the expression profiles of circRNAs were compared in ovary tissues from Yili geese in three different breeding periods, namely the prelaying period (KL), laying period (CL), and ceased period (XL), and differentially expressed circRNAs related to ovarian development in Yili geese were screened. The potential biological functions of differential circRNAs were predicted by bioinformatics, and the differential circRNA-miRNA regulatory network was constructed.

RESULTS

The results showed that a total of 4483 circRNAs were identified in 12 ovarian tissue samples from Yili geese at different laying stages. In the KL vs. CL, XL vs. CL, and XL vs. KL groups, 159, 455, and 383 differentially expressed circRNAs were identified, respectively. The host genes of the differential circRNAs were mostly enriched in the signal transduction, metabolism, and other related pathways, such as those for phototransduction, glycerophospholipid metabolism, aminoacyl-tRNA biosynthesis, and retinol metabolism. Finally, we constructed circRNA-miRNA regulation networks. Nine differential circRNAs were randomly selected for qRT-PCR verification, and the expression trends were consistent with the sequencing results.

CONCLUSIONS

Our results indicated that significant differences in the expression profiles of circRNAs in the ovaries of Yili geese at different egg-laying stages. Meanwhile, through analyzing the differential circRNA-miRNA interaction network, core regulators such as circRNA NW_013186107.1:36835|52,574 and gga-miR-34b-5p were screened. This study provides a reference for the further analysis of the molecular regulatory mechanism of the circRNAs regulating goose ovary development and enriches the theory of genetic regulation during goose ovary development.

Ovarian transcriptome profile from pre-laying period to broody period of Xupu goose

Xupu goose, a breed from Hunan province, produces high quality and quantity of meat and liver. However, its egg production rate is low, with poor reproductive traits but strong broody performance. These characteristics decrease the economic value of Xupu goose significantly. Here, RNA-seq was used to analyze the transcriptome changes of ovaries of Xupu goose at different stages to explore the molecular mechanism of reproduction from the pre-laying period to the broody period. A total of 258 genes were differentially expressed in the 3 stages. These genes are associated with inflammation, reproduction, mutual recognition and adhesion between cells, and cytoskeleton formation, and so on. In particular, we report, for the first time, the expression patterns of MRP126, serglycin, TXNIP, and FZD2 during the pre-laying, egg-laying, and broody periods of goose ovaries. Functional analysis by GO annotation revealed that GO terms were mainly involved in actin, cell signal transduction and regulation, and cellular components. Three pathways, including focal adhesion (gga04510), ECM-receptor interaction (gga04512), and N-Glycan biosynthesis (gga00510), were significantly enriched in the three groups. These findings provide a basis for further exploration of profiles of goose ovaries to improve egg production of Xupu goose.

Identification and analysis of novel microRNAs provide insights to reproductive capacity of the cultured Asian yellow pond turtle Mauremys mutica

The crucial roles of miRNAs in regulating animal growth, development, and disease resistance have been extensively reported, but their roles in relation to the reproductive capacity of aquatic animals (numbers of eggs laid and hatchlings), especially reptiles, remain unclear. In this study, high-throughput sequencing technology was used to screen miRNAs related to reproductive capacity based on the construction of a cDNA library of ovaries from higher-fecundity (HF) and lower-fecundity (LF) M. mutica. The results showed that 15,767,494 (93.98%) and 14,137,621 (94.17%) high-quality reads were obtained from the HF and LF groups, respectively. We screened 131 miRNAs that were differentially expressed between the HF and LF groups, of which 78 were upregulated and 53 were downregulated compared with the M. mutica reference genome. GO and KEGG pathway enrichment analyses of the target genes of differentially expressed miRNAs revealed significant differences in the enrichment frequencies of genes associated with ATP binding and proteolysis between the HF and LF groups, while the tricarboxylic acid cycle, glucagon signaling pathway and vitamin B6 metabolic pathway were shown to potentially help determine reproductive capacity. Ten miRNAs were verified by qRT-PCR to confirm the reliability and accuracy of the sequencing results, and a miRNA-mRNA target gene interaction network was constructed. These results will further our understanding of the regulatory mechanism of miRNAs in regards to turtle reproductive capacity.

Long noncoding RNAs profiling in ovary during laying and nesting in Muscovy ducks (Cairina moschata)

There are recent reports of the important functions of long noncoding RNAs (lncRNAs) in female reproductive and ovarian development. Studies in which there was characterization of lncRNAs in the ovaries of laying compared with nesting poultry, however, are limited. In this study, RNA libraries were constructed by obtaining sequencing data of ovarian tissues from laying and nesting Muscovy ducks. In the ovarian tissues of Muscovy ducks, a total of 334 differentially abundant mRNA transcripts (DEGs) and 36 differentially abundant lncRNA transcripts were identified in the nesting period, when compared with during the laying period. These results were subsequently validated by qRT-PCR using nine randomly-selected lncRNAs and six randomly-selected DAMTs. Furthermore, the cis- and trans-regulatory target genes of differentially abundant lncRNA transcripts were identified, and lncRNA-gene interaction networks of 34 differentially abundant lncRNAs and 263 DEGs were constructed. A total of 7601 lncRNAs neighboring 10,542 protein-coding genes were identified and found to be enriched in the Wnt signaling pathway and oocyte meiosis pathways associated with follicular development. Overall, only 11 cis-targets and 57 mRNA-mRNA except trans-targets were involved in the lncRNA-gene interaction networks. Based on the interaction networks, nine DEGs were trans-regulated by differentially abundant lncRNAs and 20 differentially abundant lncRNAs were hypothesized to have important functions in the regulation of broodiness in Muscovy ducks. In this study, a predicted interaction network of differentially abundant lncRNAs and DEGs in Muscovy ducks was constructed for the first time leading to an enhanced understanding of lncRNA and gene interactions regulating broodiness.

MiR-181a-5p inhibits goose granulosa cell viability by targeting SIRT1

1. Granulosa cells (GCs) are involved in folliculogenesis, follicular development, and atresia. Previous studies have shown that microRNA-181a-5p (miR-181a-5p) and sirtuin 1 (SIRT1) are involved in GC proliferation and apoptosis, and SIRT1 has been predicted as one target of miR-181a-5p. However, there are few studies with poultry.2. Quantitative real-time PCR (qRT-PCR) was used to detect the expression level of miR-181a-5p in granulosa layers during geese ovarian follicular development. A methyl thiazolyl tetrazolium (MTT) assay was performed to assess the viability of geese granulosa cells treated with miR-181a-5p mimic or inhibitor. The binding sites between the SIRT1 3'-UTR region and miR-181a-5p were evaluated using a luciferase reporter assay system. SIRT1 mRNA levels were detected using qRT-PCR after transfection with miR-181a-5p mimic and inhibitor.3. The miR-181a-5p suppressed geese GC viability and regulated the mRNA expression of viability-related genes in geese GCs. SIRT1 was a target gene of miR-181a-5p and miR-181a-5p suppressed its mRNA expression.4. The miR-181a-5p may target and inhibit SIRT1 expression, thus suppressing GC viability by regulating viability-related key genes.

The miRNAs profiling revealed by high-throughput sequencing upon WSSV infection in mud crab Scylla paramamosain

microRNAs (miRNAs) are known to regulate various immune functions by silencing the target genes in both vertebrates and invertebrates. However, in mud crab Scylla paramamosain, the role of miRNAs during the response to virus invasion remains unclear. To investigate the roles of miRNAs in S. paramamosain during virus infection, the mud crab was challenged with white spot syndrome virus (WSSV) and then subjected to the transcriptional analysis at different conditions. The results of high-throughput sequencing revealed that 940,379 and 1,306,023 high-quality mappable reads were detected in the hemocyte of normal and WSSV-infected mud crabs, respectively. Besides, the total number of 261 unique miRNAs were identified. Among them, 131 miRNAs were specifically expressed in the hemocytes of normal mud crabs, 46 miRNAs were specifically transcribed in those of WSSV-infected individuals, the other 84 miRNAs were expressed in both normal and WSSV-infected individuals. Furthermore, a number of 152 (89 down-regulated and 63 up-regulated) miRNAs were found to be differentially expressed in the WSSV-infected hemocytes, normalized to the controls. The identified miRNAs were subjected to GO analysis and target gene prediction and the results suggested that the differentially regulated miRNAs were mainly correlated with the changes of the immune responses of the hemocytes, including phagocytosis, melanism, and apoptosis as well. Taken together, the results demonstrated that the expressed miRNAs during the virus infection were mainly involved in the regulation of immunological pathways in mud crabs. Our findings not only enrich the understanding of the functions of miRNAs in the innate immune system but also provide some novel potential targets for the prevention of WSSV infection in crustaceans.

Changes in morphology and miRNAs expression in small intestines of Shaoxing ducks in response to high temperature

During summer days the extreme heat may cause damage to the integrity of animal intestinal barrier. Little information is available concerning morphological changes in the duck intestines in response to high temperature. And the molecular mechanisms underlying the pathogenesis of high temperature-induced intestinal injury remain undefined. MicroRNAs (miRNAs) are known to play key roles in post-transcriptional regulation of gene expression that influences various biological processes. The purpose of this study was to explore the changes in morphology and miRNA expression profiles of the three intestinal segments (duodenum, jejunum and ileum) of ducks in response to high temperature. Sixty female Shaoxing ducks (Anas platyrhynchos), 60 days old, were allocated in two groups, including control ducks kept at 25 °C, and ducks subjected to high ambient temperatures of 30-40 °C for 15 successive days, which mimicked the diurnal temperature variations experienced in hot seasons. Three ducks from each group were executed at the end of feeding experiment, and the samples of three intestinal segments were collected for morphological examination and Illumina deep sequencing analyses. Histopathological examination of the intestinal mucous membrane was performed with HE staining method. The results demonstrated that varying degrees of damage to each intestinal segment were found in heat-treated ducks, and there were more severe injuries in duodenum and jejunum than those in ileum. Illumina high-throughput sequencing and bioinformatic methods were employed in this study to identify the miRNA expression profile of three different intestinal tissues in control and heat-treated ducks. A total of 75,981,636, 88,345,563 and 100,179,422 raw reads were obtained from duodenum, jejunum and ileum, respectively, from which 74,797,633 clean reads in duodenal libraries, 86,406,445 clean reads in jejunal libraries, and 98,518,858 lean reads in ileal libraries were derived after quality control, respectively. And a total of 276 known and 182 novel miRNAs were identified in the three intestinal segments of ducks under control and heat-treated conditions. By comparing the same tissues in different conditions, 16, 18 and 15 miRNAs were found to be significantly differentially expressed between control and heat-treated ducks in duodenum, jejunum and ileum, respectively, of which 1 miRNA was expressed in both the duodenum and jejunum, 2 miRNAs were expressed in both the duodenum and ileum, and 3 miRNAs were found to be expressed in both the jejunum and ileum. In addition, two differentially expressed miRNAs in each comparison were randomly selected and validated by quantitative qRT-PCR. Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the differentially expressed miRNAs may be involved in the high temperature-induced intestinal injury in ducks. Our work provides the comprehensive miRNA expression profiles of small intestines in the normal and heat-treated ducks. These findings suggest the involvement of specific molecular mechanisms of post-transcriptional regulation to explain the high temperature-induced changes in the duck small intestine.

MicroRNAs in ovarian follicular atresia and granulosa cell apoptosis

MicroRNAs (miRNAs) are short, noncoding RNAs that posttranscriptionally regulate gene expression. In the past decade, studies on miRNAs in ovaries have revealed the key roles of miRNAs in ovarian development and function. In this review, we first introduce the development of follicular atresia research and then summarize genome-wide studies on the ovarian miRNA profiles of different mammalian species. Differentially expressed miRNA profiles during atresia and other biological processes are herein compared. In addition, current knowledge on confirmed functional miRNAs during the follicular atresia process, which is mostly indicated by granulosa cell (GC) apoptosis, is presented. The main miRNA families and clusters, including the let-7 family, miR-23-27-24 cluster, miR-183-96-182 cluster and miR-17-92 cluster, and related pathways that are involved in follicular atresia are thoroughly summarized. A deep understanding of the roles of miRNA networks will not only help elucidate the mechanisms of GC apoptosis, follicular development, atresia and their disorders but also offer new diagnostic and treatment strategies for infertility and other ovarian dysfunctions.

Whole-transcriptome analysis of atrophic ovaries in broody chickens reveals regulatory pathways associated with proliferation and apoptosis

Broodiness in laying hens results in atrophy of the ovary and consequently decreases productivity. However, the regulatory mechanisms that drive ovary development remain elusive. Thus, we collected atrophic ovaries (AO) from 380-day-old broody chickens (BC) and normal ovaries (NO) from even-aged egg-laying hens (EH) for RNA sequencing. We identified 3,480 protein-coding transcripts that were differentially expressed (DE), including 1,719 that were down-regulated and 1,761 that were up-regulated in AO. There were 959 lncRNA transcripts that were DE, including 56 that were down-regulated and 903 that were up-regulated. Among the116 miRNAs that were DE, 79 were down-regulated and 37 were up-regulated in AO. Numerous DE protein-coding transcripts and target genes for miRNAs/lncRNAs were significantly enriched in reproductive processes, cell proliferation, and apoptosis pathways. A miRNA-intersection gene-pathway network was constructed by considering target relationships and correlation of the expression levels between ovary development-related genes and miRNAs. We also constructed a competing endogenous RNA (ceRNA) network by integrating competing relationships between protein-coding genes and lncRNA transcripts, and identified several lncRNA transcripts predicted to regulate the CASP6, CYP1B1, GADD45, MMP2, and SMAS2 genes. In conclusion, we discovered protein-coding genes, miRNAs, and lncRNA transcripts that are candidate regulators of ovary development in broody chickens.

High-throughput sequencing reveals novel lincRNA in age-related cataract

Age-related cataract (ARC) is a major cause of blindness. Long non-coding RNAs (lncRNAs) are a heterogeneous class of RNAs that are non-protein-coding transcripts >200 nucleotides in length. LncRNAs are involved in various critical biological processes, such as chromatin remodeling, gene transcription, and protein transport and trafficking. Furthermore, the dysregulation of lncRNAs causes a number of complex human diseases, including coronary artery diseases, autoimmune diseases, neurological disorders and various cancers. However, the role of lncRNA in cataract remains unclear. Therefore, in the present study, lens anterior capsular membrane was collected from normal subjects and patients with ARC and total RNA was extracted. High-throughput sequencing was applied to detect differentially expressed lncRNAs and mRNAs. The analysis identified a total of 42,556 candidate differentially expressed mRNAs (27,447 +15,109) and a total of 7,041 candidate differentially expressed lncRNAs (4,146 + 2,895). Through bioinformatics analysis, the significant differential expression of novel lincRNA was observed and its possible molecular mechanism was explored. Reverse transcription-quantitative polymerase chain reaction was used to validate the different expression levels of selected lncRNAs. These findings may lead to the development of novel strategies for genetic diagnosis and gene therapy.

Transcriptome analysis of follicles reveals the importance of autophagy and hormones in regulating broodiness of Zhedong white goose

Broodiness, a maternal behavior and instinct for natural breeding in poultry, inhibits egg production and affects the poultry industry. Phenotypic and physiological factors influencing broodiness in poultry have been extensively studied, but the molecular regulation mechanism of broodiness remains unclear. Effective research strategies focusing on broodiness are hindered by limited understanding of goose developmental biology. Here we established the transcriptomes of goose follicles at egg-laying and broody stages by Illumina HiSeq platform and compared the sequenced transcriptomes of three types of follicles (small white, large white and small yellow). It was found that there were 92 up-regulated and 84 down-regulated transcription factors and 101 up-regulated and 51 down-regulated hormone-related genes. Many of these genes code for proteins involved in hormone response, follicular development, autophagy, and oxidation. Moreover, the contents of progesterone and estradiol in follicles were altered, and the autophagy levels of follicles were enhanced during the broody stage. These results suggest that hormone- and autophagy-signaling pathways are critical for controlling broodiness in the goose. We demonstrated that transcriptome analysis of egg-laying and broody Zhedong white goose follicles provided novel insights into broodiness in birds.