MAPK8 regulates chicken male germ cell differentiation through JNK signaling pathway

miR-1458 is inhibited by low concentrations of Vitamin B6 and targets TBX6 to promote the formation of spermatogonial stem cells in Rugao Yellow Chicken

Spermatogonial stem cells (SSCs) have vast application prospects in livestock and poultry production, genetic engineering, and medical research. However, the scarcity of SSCs and the complexity of their development limit the elucidation and verification of the mechanism of SSCs in vitro. Although miRNAs have been identified as critical players in germ cell development, upstream regulatory mechanisms by which miRNAs regulate SSCs formation are rarely reported. In this study, miR-1458, which was differentially expressed during SSCs formation, was selected by transcriptomic sequencing. We found that miR-1458, inhibited in an in vitro SSCs induction model, significantly upregulated the expression of germline marker genes (Cvh and integrin β1). Further analysis using Immunofluorescence and Flow Cytometry confirmed that miR-1458 inhibition promotes the formation of spermatogonial stem-like cells (SSCLCs). Immunohistochemical significantly increased the number of SSCs in the testis in vivo. However, significant upregulation of miR-1458 showed opposite results. High-throughput sequencing results showed that miR-1458 interacted with TBX6, one of the target genes of miR-1458, involved in affecting cell differentiation, and dual-luciferase reporter vectors confirmed the targeting relationship between the two. TBX6 overexpression and knockdown in vitro and in vivo have validated its function in SSCs formation. We found that overexpression of TBX6 promoted SSCs formation. Additionally, we identified Vitamin B6, a key metabolite affecting SSCs formation, as an upstream regulator of miR-1458 expression. The results showed that low concentrations of Vitamin B6 led to low expression of miR-1458 by decreasing histone demethylation levels. Overall, our findings suggest that miR-1458 is involved in SSCs formation, which is inhibited by low concentrations of Vitamin B6 and subsequently regulates the formation of SSCs by targeting TBX6, an essential gene involved in embryonic stem cell differentiation. Our study demonstrates the critical role of the Vitamin B6-miR-1458-TBX6 regulatory axis in spermatogonial stem cell formation in Rugao Yellow Chicken, providing new insights into the regulatory mechanisms by which miRNAs affect SSCs formation. It should be noted that most of the germline findings related to miRNAs were obtained by in vitro studies, and in vivo studies are needed to validate our results for clinical applications.

The JNK signalling pathway gene BmJun is involved in the regulation of egg quality and production in the silkworm, Bombyx mori

The Jun N-terminal kinase (JNK) signalling pathway has a key role in tissue remodelling during insect metamorphosis by regulating programmed cell death. However, multiple members of the JNK pathway in Lepidoptera remain uncharacterized. In this study, two key genes of the JNK pathway, BmJun and BmFos, were cloned from the silkworm Bombyx mori, a lepidopteran model insect, and their effects on reproductive development were investigated. BmJun and BmFos encode 239 and 380 amino acids, respectively. Both proteins have typical basic leucine zipper domains and form a BmJUN-BmFOS dimer activator protein to exert transcriptional regulation. During the wandering stage of silkworm development, interference in BmJun expression had no effect on pupation, whereas B. mori vitellogenin (BmVg) expression, which is essential for egg development, was suppressed in the fat body and egg laying was significantly reduced. Additionally, numerous eggs appeared shrivelled and deformed, suggesting that they were nutritionally stunted. Inhibition of the JNK pathway caused abnormal pupal metamorphosis, an increase in shrivelled, unfertilized eggs, a decrease in fat body synthesis, and accumulation of BmVg in the ovaries of female B. mori. The results indicated that BmJUN and BmFOS can form an AP-1 dimer. Interfering with BmJun or inhibiting the phosphorylation of BmJUN leads to a reduction in the synthesis of BmVg in the fat body and its accumulation in the ovaries, thereby affecting the quality and production of the progeny eggs. These findings suggest that regulating Jun in the JNK pathway could be a potential way to inhibit female reproduction in Lepidoptera.

A Study of JUN's Promoter Region and Its Regulators in Chickens

Background: The Jun proto-oncogene (JUN), also referred to as C-JUN, is an integral component of the JNK signaling pathway, which is crucial for the formation and differentiation of spermatogonial stem cells (SSCs). Investigations into the transcriptional regulation of chicken JUN can offer a molecular foundation for elucidating its mechanistic role in SSCs. Methods: In this study, we successfully cloned a 2000 bp upstream sequence of the JUN transcription start site and constructed a series of pGL3 recombinant vectors containing JUN promoters of varying lengths. Results: We verified the promoter activity of the 2000 bp upstream sequence by assessing the fluorescence intensity of DF-1 and identified the promoter activities of different regions via dual-luciferase assays. The transcription of JUN and its promoter region spanning -700 to 0 bp was modulated by an activator of the JNK signaling pathway. Bioinformatics analysis revealed that this -700 to 0 bp region was highly conserved among avian species and predicted the presence of binding sites for Wilms tumor 1 (WT1) and CCAAT/enhancer binding protein alpha (CEBPA). The JNK signaling pathway activator was found to upregulate the expression of these transcription factors in DF-1 cells. Through the deletion of binding sites and the overexpression of WT1 and CEBPA, we demonstrated that WT1 inhibited the transcription of JUN, while CEBPA promoted it. Conclusions: In conclusion, the -700 to 0 bp region is the key region of the JUN promoter, with WT1 inhibiting JUN transcription. The results of the study not only provide ideas for exploring the regulatory mechanism of JUN in chicken SSCs, but also lay an important foundation for the study of avian SSCs.

Di-n-butyl phthalate induces toxicity in male fetal mouse testicular development by regulating the MAPK signaling pathway

"White pollution" has a significant impact on male reproduction. Di-n-butyl phthalate (DBP) is one of the most important factors in this type of pollution. Currently, research from international sources has demonstrated the significant reproductive toxicity of DBP. However, most of these studies have focused mainly on hormones expression at the protein and mRNA levels and the specific molecular targets of DBP and its mechanisms of action remain unclear. In this study, we established a Sprague Dawley pregnant mouse model exposed to DBP, and all male offspring were immediately euthanized at birth and bilateral testes were collected. We found through transcriptome sequencing that cell apoptosis and MAPK signaling pathway are the main potential pathways for DBP induced reproductive toxicity. Molecular biology analyses revealed a significant increase in the protein levels of JNK1(MAPK8) and BAX, as well as a significant increase in the BAX/BCL2 ratio after DBP exposure. Therefore, we propose that DBP induces reproductive toxicity by regulating JNK1 expression to activate the MAPK signaling pathway and induce reproductive cell apoptosis. In conclusion, our study provides the first evidence that the MAPK signaling pathway is involved in DBP-induced reproductive toxicity and highlights the importance of JNK1 as a potential target of DBP in inducing reproductive toxicity.

Identification of key events and regulatory networks in the formation process of primordial germ cell based on proteomics

Currently, studies have analyzed the formation mechanism of primordial germ cell (PGC) at the transcriptional level, but few at the protein level, which made the mechanism study of PGC formation not systematic. Here, we screened differential expression proteins (DEPs) regulated PGC formation by label-free proteomics with a novel sampling strategy of embryonic stem cells and PGC. Analysis of DEPs showed that multiple key events were involved, such as the transition from glycolysis to oxidative phosphorylation, activation of autophagy, low DNA methylation ensured the normal formation of PGC, beyond that, protein ubiquitination also played an important role in PGC formation. Importantly, the progression of such events was attributed to the inconsistency between transcription and translation. Interestingly, MAPK, PPAR, Wnt, and JAK signaling pathways not only interact with each other but also interact with different events to participate in the formation of PGC, which formed the PGC regulatory network. According to the regulatory network, the efficiency of PGC formation in induction system can be significantly improved. In conclusion, our results indicate that chicken PGC formation is a complex process involving multiple events and signals, which provide technical support for the specific application in PGC research.

Retinoic acid promotes formation of chicken (Gallus gallus) spermatogonial stem cells by regulating the ECM-receptor interaction signaling pathway

Spermatogonial stem cells (SSCs) are the basis of spermatogenesis. Systematically exploring the critical factors associated with the formation of SSCs will provide new insight to improve the formation efficiency, and their practical application. Here we explore the regulatory mechanism of the ECM-receptor interaction signaling pathway and related genes during differentiation of SSCs in chicken. Firstly, the positive cell rate of SSCs protein marker was detected by immunofluorescence and flow cytometry and qRT-PCR was used to identify, the expression of related marker genes after 10 days of RA-induction. Secondly, the ESCs on 0d/ 4d /10d after RA- induction/self-differentiation were collected, and the total RNA was then extracted from cells. Finally, high-throughput analysis methods (RNA-seq) were used to sequence the transcriptome of these cells. After PCA analysis of the RNA-seq data, Venny analysis, GO and KEGG enrichment were further used to find the key signaling pathways and genes in the RA-induction process. The results showed that on day 10 of RA-induction, grape cluster growth cells expressed integrinβ1, the specific marker protein of SSCs cells, and the integrinβ1 positive rate was 35.1%. Also, SSCs marker genes CVH, Integrinβ1, Integrinα6 were significantly up-regulated during RA-induction. Moreover, the significantly enriched pathway, ECM-receptor interaction signaling, in current study may play a crucial role in RA-induction. Then, JASPAR was used to predict the differential gene transcription factors in the signaling pathway, finding that RA receptor was a transcription factor of COL5A1, COL5A2 and COL3A1. The qRT-PCR results showed that the expression levels of RA receptors (RXRA, RARA and RXRG) and the predicted genes (COL5A1, COL5A2 and COL3A1) were both significantly increased during RA-induction. Also, dual-luciferase reporter assay showed that RA could affect the luciferin activities of COL5A1, COL5A2 and COL3A1. These results suggest that RA plays a crucial role in the formation of chicken spermatogonial stem cells via the transcription levels of COL5A1, COL5A2 and COL3A1 to regulate the ECM-receptor interaction signaling pathway. Additionally, knockdown of COL5A1/COL5A2/COL3A1 could effectively reduce the formation efficiency of SSCs. This indicated that the interference of RA receptor binding genes in the ECM-receptor interaction signaling pathway could decrease the efficiency of RA induced SSCs formation. Therefore, this study concludes that RA promotes formation of chicken spermatogonial stem cells by regulating the ECM-receptor interaction signaling pathway.

Circular RNA ACTA1 Acts as a Sponge for miR-199a-5p and miR-433 to Regulate Bovine Myoblast Development through the MAP3K11/MAP2K7/JNK Pathway

Circular RNAs (circRNAs) are a special class of noncoding RNA molecules that regulate many different biological processes. Myogenesis, a complex process, is primarily regulated by myogenic regulatory factors (MRFs) and various noncoding RNAs. However, the functions and regulatory mechanisms of circRNAs in myoblast development are unclear. In this study, we analyzed circRNA sequencing data of bovine myocyte tissues and identified circACTA1. Functional assays showed that circACTA1 could inhibit bovine myocyte proliferation and promote cell apoptosis and cytodifferentiation. In addition, circACTA1 could promote muscle repair in vivo. Mechanistically, luciferase assay and RNA immunoprecipitation were used to examine the interaction between circACTA1, miR-199a-5p, miR-433, and the target genes MAP3K11 and MAPK8. Meanwhile, we found that miR-199a-5p and miR-433 could suppress the expression of MAP3K11 and MAPK8, respectively. However, circACTA1 could mitigate this effect and activate the JNK signaling pathway. In conclusion, our results suggest that circACTA1 regulates the multiplication, apoptosis, and cytodifferentiation of bovine myocytes by competitively combining with miR-199a-5p and miR-433 to activate the mitogen-activated protein kinase kinase kinase 11 (MAP3K11)/mitogen-activated protein kinase kinase 7 (MAP2K7)/JNK signaling pathway.

miR-302d Competitively Binding with the lncRNA-341 Targets TLE4 in the Process of SSC Generation

MicroRNAs (miRNAs) are essential factors in the reproductive process of poultry. Here, we found miR-302d is a potential differentiation and negative factor of chicken embryonic stem cells (ESCs) into spermatogonia stem cells (SSCs). The competition mechanism was carried out for the preliminary exploration to determine the relationship among miR-302d, lncRNA-341(interacting with miR-302d), and target gene TLE4. The results showed that lncRNA-341 can competitively bind to miR-302d to decrease the targeted binding of miR-302d and TLE4 which promotes the differentiation of chicken SSCs. Moreover, it is suggested that miR-302d may participate in the Wnt signaling pathway through TLE4.

Study on the transcriptome for breast muscle of chickens and the function of key gene RAC2 on fibroblasts proliferation

BACKGROUND

Growth performance is significant in broiler production. In the growth process of broilers, gene expression varies at different growth stages. However, limited research has been conducted on the molecular mechanisms of muscle growth and development in yellow-feathered male chickens.

RESULTS

In the study, we used RNA-seq to study the transcriptome of the breast muscle of male Jinghai yellow chickens at 4 (M4F), 8 (M8F) and 12 weeks (M12F) of age. The results showed that 4608 differentially expressed genes (DEGs) were obtained by comparison in pairs of the three groups with Fold Change (FC) ≥ 2 and False Discovery Rate (FDR) ≤ 0.05, and 83, 3445 and 3903 DEGs were obtained separately from M4FvsM8F, M4FvsM12F and M8FvsM12F. Six genes were found as co-differentially expressed in the three age groups, namely SNCG, MYH1A, ARHGDIB, ENSGALG00000031598, ENSGALG00000035660 and ENSGALG00000030559. The GO analysis showed that 0, 304 and 408 biological process (BP) were significantly enriched in M4FvsM8F, M4FvsM12F and M8FvsM12F groups, respectively. KEGG pathway enrichment showed that 1, 2, 4 and 4 pathways were significantly enriched in M4FvsM8F, M4FvsM12F, M8FvsM12F and all DEGs, respectively. They were steroid biosynthesis, carbon metabolism, focal adhesion, cytokine-cytokine receptor interaction, biosynthesis of amino acids and salmonella infection. We constructed short hairpin RNA (shRNA) to interfere the differentially expressed gene RAC2 in DF-1 cells and detected mRNA and protein expression of the downstream genes PAK1 and MAPK8. Results of qPCR showed that RAC2, PAK1 and MAPK8 mRNA expression significantly decreased in the shRAC2-2 group compared with the negative control (NC) group. Western Blot (WB) results showed that the proteins of RAC2, PAK1 and MAPK8 also decreased in the shRAC2-2 group. Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) assay both showed that the proliferation of DF-1 cells was significantly inhibited after transfection of shRAC2-2.

CONCLUSIONS

The results of RNA-seq revealed genes, BP terms and KEGG pathways related to growth and development of male Jinghai yellow chickens, and they would have important guiding significance to our production practice. Further research suggested that RAC2 might regulate cell proliferation by regulating PAKs/MAPK8 pathway and affect growth of chickens.

P53 and H3K4me2 activate N6-methylated LncPGCAT-1 to regulate primordial germ cell formation via MAPK signaling

Long noncoding RNAs (lncRNAs) participate in the formation of primordial germ cells (PGCs); however, the identity of the key lncRNAs and the molecular mechanisms responsible for the formation of PGCs remain unknown. Here, we identify a key candidate lncRNA (lncRNA PGC transcript-1, LncPGCAT-1) via RNA sequencing of embryonic stem cells, PGCs, and Spermatogonial stem cells (SSCs). Functional experiments confirmed that LncPGCAT-1 positively regulated the formation of PGCs by elevating the expression of Cvh and C-kit while downregulating the pluripotency(Nanog) in vitro and in vivo; PAS staining of genital ridges in vivo also showed that interference with LncPGCAT-1 can significantly reduce the number of PGCs in genital ridges, while overexpression of LncPGCAT-1 had the opposite result. The result of luciferase reporter assay combined with CHIP-qPCR showed that the expression of LncPGCAT-1 was promoted by the transcription factor P53 and high levels of H3K4me2. Mechanistically, the luciferase reporter assay confirmed that mitogen-activated protein kinase 1 (MAPK1) was the target gene of LncPGCAT-1 and gga-mir-1591. In the ceRNA system, high levels of N⁶ methylation of LncPGCAT-1 enhanced the adsorption capacity of LncPGCAT-1 for gga-mir-1591. Adsorption of gga-mir-1591 activated the MAPK1/ERK signaling cascade by relieving the gga-mir-1591-dependent inhibition of MAPK1 expression. Moreover, LncPGCAT-1 interacted with interleukin enhancer binding factor 3 (ILF3) to regulate the ubiquitination of P53 and phosphorylation of JNK. Interaction with ILF3 resulted in positive self-feedback regulation of LncPGCAT-1 and activation of JNK signaling, ultimately promoting PGC formation. Altogether, the study expands our knowledge of the function and molecular mechanisms of lncRNAs in PGC development.