CD49f-positive testicular cells in Saanen dairy goat were identified as spermatogonia-like cells by miRNA profiling analysis

Evaluation of Female Recipient Infertility and Donor Spermatogonial Purification for Germ Cell Transplantation in Paralichthys olivaceus

Since the advent of germ cell transplantation (GCT), it has been widely used in shortening the fish breeding cycle, sex-controlled breeding and the protection of rare and endangered fish. In this study, the effectiveness of female sterile recipient preparation and donor stem cell isolation and purification were comprehensively evaluated for spermatogonial stem cell transplantation (SSCT) in Paralichthys olivaceus. The best way to prepare sterile recipients was found to be giving three-year-old fish four intraovarian injections of busulfan (20 mg/kg body weight) combined with exposure to a high temperature (28 °C) after the spawning season compared with the two other ways, which induced apoptosis of most of the endogenous germ cells, resulting in shrinkage of the spawning plate and enlargement of the ovarian lumen. Further analysis showed that both the gonadosomatic index and germ-cell-specific vasa expression were significantly lower than those of the natural-temperature group before treatment (p < 0.05). A high percentage (>60.00%) of spermatogonial stem cells (SSCs) were obtained after isolation and purification and were transplanted into the prepared recipients. After three weeks of SSCT, the numbers of PKH26-labeled SSCs were increased in the ovaries of the recipients. These findings provide a basis for the establishment of an ideal SSCT technique using P. olivaceus females as the recipients, ultimately contributing to the efficient conservation of male germplasm resources and effective breeding.

Elucidating the Role of OXPHOS Variants in Asthenozoospermia: Insights from Whole Genome Sequencing and an In Silico Analysis

Infertility is a global health challenge that affects an estimated 72.4 million people worldwide. Between 30 and 50% of these cases involve male factors, showcasing the complex nature of male infertility, which can be attributed to both environmental and genetic determinants. Asthenozoospermia, a condition characterized by reduced sperm motility, stands out as a significant contributor to male infertility. This study explores the involvement of the mitochondrial oxidative phosphorylation (OXPHOS) system, crucial for ATP production and sperm motility, in asthenozoospermia. Through whole-genome sequencing and in silico analysis, our aim was to identify and characterize OXPHOS gene variants specific to individuals with asthenozoospermia. Our analysis identified 680,099 unique variants, with 309 located within OXPHOS genes. Nine of these variants were prioritized due to their significant implications, such as potential associations with diseases, effects on gene expression, protein function, etc. Interestingly, none of these variants had been previously associated with male infertility, opening up new avenues for research. Thus, through our comprehensive approach, we provide valuable insights into the genetic factors that influence sperm motility, laying the foundation for future research in the field of male infertility.

Combined analysis of mRNA-miRNA from testis tissue in Tibetan sheep with different FecB genotypes

Testis size is important for identifying breeding animals with adequate sperm production. The aim of this study was to survey the expression profile of mRNA and miRNA in testis tissue from rams carrying different FecB genotypes, including the wild-type and heterozygous genotypes in Tibetan sheep. Comparative transcriptome profiles for ovine testes were established for wild-type and heterozygote Tibetan sheep by next-generation sequencing. RNA-seq results identified 3,910 (2,034 up- and 1,876 downregulated) differentially expressed (DE) genes and 243 (158 up- and 85 downregulated) DE microRNAs (miRNAs) in wild-type vs heterozygote sheep, respectively. Combined analysis of mRNA-seq and miRNA-seq revealed that 20 miRNAs interacted with 48 true DE target genes in wild-type testes compared to heterozygous genotype testes. These results provide evidence for a functional series of genes operating in Tibetan sheep testis. In addition, quantitative real-time PCR analysis showed that the expression trends of randomly selected DE genes in testis tissues from different genotypes were consistent with high-throughput sequencing results.

Integrated analysis of miRNA and mRNA expression profiles in testes of Landrace and Hezuo boars

Precocious puberty is closely related to testicular development and spermatogenesis, and there is increasing evidence that miRNAs are involved in regulation of testicular development and spermatogenesis. However, little is known about the regulation of microRNAs (miRNAs) during precocious maturation in Hezuo (HZ) boars. In this study, serum Testosterone (T), Estradiol (E₂), Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) levels were detected in HZ and Landrace (LC) boars in the postnatal period at 30, 90, 120, 180, and 240 days, and the testes of HZ and LC boars at 30 and 120 days were used for histological observation. In addition, we performed small RNA-Seq to identify miRNA at sexual immaturity (30-days-old) and maturity (120-days-old) of HZ boar testis (using LC boar as control) to reveal the key miRNA in regulation of precocious puberty. Hormone assay results showed that high levels of T, E₂, FSH, and LH may be related to precocious sexual maturity of HZ boars, and that FSH may play an important function before sexual maturity. Histological observation showed that HZ boars developed earlier than LC boars and had reached sexual maturity at 120 days. Small RNA-Seq yielded a total of 359 exist miRNAs, 767 known miRNAs and 322 novel miRNAs in 12 samples; 549, 468, 133, and 247 differentially expressed (DE) miRNAs were identified between Ha vs. Hb, La vs. Lb, Ha vs. La, and Hb vs. Lb (log₂ fold change >1 and p < 0.05). Enrichment analysis showed that target genes of these DE miRNAs were enriched in many gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways (such as PI3K-Akt, Hippo and Rap1 signaling pathways) were related to testicular development and spermatogenesis. Further screening, some miRNAs (such as ssc-miR-29b, ssc-miR-199b, ssc-miR-383, ssc-miR-149, ssc-miR-615, and ssc-miR-370) were possibly associated with precocious puberty. These results provide new light on miRNA regulatory mechanisms involved in precocious puberty.

Culture of spermatogonial stem cells and use of surrogate sires as a breeding technology to propagate superior genetics in livestock production: A systematic review

Background and Aim:

Spermatogonial stem cells (SSCs) have previously been isolated from animals’ testes, cultured in vitro, and successfully transplanted into compatible recipients. The SSC unique characteristic has potential for exploitation as a reproductive tool and this can be achieved through SSC intratesticular transplantation to surrogate sires. Here, we aimed at comprehensively analyzing published data on in vitro maintenance of SSC isolated from the testes of livestock animals and their applications.

Materials and Methods:

The literature search was performed in PubMed, Science Direct, and Google Scholar electronic databases. Data screening was conducted using Rayyan Intelligent Systematic Review software (https://www.rayyan.ai/). Duplicate papers were excluded from the study. Abstracts were read and relevant full papers were reviewed for data extraction.

Results:

From a total of 4786 full papers screened, data were extracted from 93 relevant papers. Of these, eight papers reported on long-term culture conditions (>1 month) for SSC in different livestock species, 22 papers on short-term cultures (5-15 days), 10 papers on transfection protocols, 18 papers on transplantation using different methods of preparation of livestock recipients, and five papers on donor-derived spermatogenesis.

Conclusion:

Optimization of SSC long-term culture systems has renewed the possibilities of utilization of these cells in gene-editing technologies to develop transgenic animals. Further, the development of genetically deficient recipients in the endogenous germline layer lends to a future possibility for the utilization of germ cell transplantation in livestock systems.

MicroRNAs: Potential biomarkers for reproduction, diagnosis, prognosis, and therapeutic in domestic animals

MicroRNA (miRNAs) are small non-coding RNA molecules involved in a wide range of biological processes through the post-transcriptional regulation of gene expression. Most studies evaluated microRNA expression in human, and despite fewer studies in veterinary medicine, this topic is one of the most exciting areas of modern veterinary medicine. miRNAs showed to be part of the pathogenesis of diseases and reproduction physiology in animals, making them biomarkers candidates. This review provides an overview of the current knowledge regarding miRNAs' role in reproduction and animal diseases, diagnostic and therapy.

PAX7 promotes CD49f-positive dairy goat spermatogonial stem cells' self-renewal

Spermatogenesis is a complex process that originates from and depends on the spermatogonial stem cells (SSCs). The number of SSCs is rare, which makes the separation and enrichment of SSCs difficult and inefficient. The transcription factor PAX7 maintains fertility in normal spermatogenesis in mice. However, for large animals, much less is known about the SSCs' self-renewal regulation, especially in dairy goats. We isolated and enriched the CD49f-positive and negative dairy goat testicular cells by magnetic-activated cell sorting strategies. The RNA- sequencing and experimental data revealed that cells with a high CD49f and PAX7 expression are undifferentiated spermatogonia in goat testis. Our findings indicated that ZBTB16 (PLZF), PAX7, LIN28A, BMPR1B, FGFR1, and FOXO1 were expressed higher in CD49f-positive cells as compared to negative cells and goat fibroblasts cells. The expression and distribution of PAX7 in dairy goat also have been detected, which gradually decreased in testis tissue along with the increasing age. When the PAX7 gene was overexpressed in dairy goat immortal mGSCs-I-SB germ cell lines, the expression of PLZF, GFRα1, ID4, and OCT4 was upregulated. Together, our data demonstrated that there is a subset of spermatogonial stem cells with a high expression of PAX7 among the CD49f⁺ spermatogonia, and PAX7 can maintain the self-renewal of CD49f-positive SSCs.

The construction and application of lentiviral overexpression vector of goat miR-204 in testis

The miRNA gene in DNA is first transcribed to Pri-miRNA, and then processed to Pre-miRNA, a stem-loop RNA segment (precursor) and further to miRNA which binds to mRNA by Dicer protein complex. It was confirmed that goat miR-204 could regulate the expressions of Sirt1 and the SSCs' (Spermatogonial Stem Cells) important genes Oct4 and Plzf, and inhibit the proliferation of dairy goat SSCs in vitro in our previous work. So, the research in vivo was needed next. In this study, the recombinant lentivirus vector pCDH-CMV-mir204-EF1-GreenPuro containing a goat chi-pri-mir-204 gene DNA segment was structured, and transfected into 293 T cells for packaged lentivirus, which then were injected into mouse seminiferous tubules. After 7 days, the goat miR-204 and the related genes such as Sirt1 and Plzf were detected in the mouse testis. This work laid a good foundation for further study of miR-204 biological function in vivo.

LIN28A activates the transcription of NANOG in dairy goat male germline stem cells

LIN28A serves as a crucial marker of dairy goat male germline stem cells (GmGSCs). In our previous study, we demonstrated that LIN28A promotes proliferation, self-renewal, and maintains the stemness of GmGSCs. Here, we found that LIN28A could activate the transcription of NANOG in a let-7g independent manner. We cloned the 5' upstream of two NANOG genes which were located on chromosome 15 ( NANOG-ch15) and chromosome 5 ( NANOG-ch5), respectively, and then examined their promoter activities and promoter methylation levels. Results showed that NANOG-ch15 is a pseudogene whereas NANOG-ch5 is active in Capra hircus. Bioinformatics analysis indicated that the 5' upstream region of NANOG-ch5 does not have typical CpG islands but contains several CG enrichment regions and several LIN28A binding sites. Deletion analysis suggested that NANOG-ch5 promoter can be activated by LIN28A directly binding to the site -210 but not by the indirect effect from the inhibition of let-7g, which is known to be downregulated by LIN28A. Mechanistically, LIN28A recruits and interacts with 5-methylcytosine-dioxygenase Ten-Eleven translocation 1 (TET1) to NANOG-ch5 gene promoter binding sites to orchestrate 5-methylcytosine and 5-hydroxymethylcytosine dynamics. These results revealed the role of LIN28A in NANOG transcriptional regulation via epigenetic DNA modifications to maintain the stemness of GmGSC.

Noncoding RNAs: Potential players in the self-renewal of mammalian spermatogonial stem cells

Spermatogonial stem cells (SSCs), a unique population of male germ cells with self-renewal ability, are the foundation for maintenance of spermatogenesis throughout the life of the male. Although many regulatory molecules essential for SSC self-renewal have been identified, the fundamental mechanism underlying how SSCs acquire and maintain their self-renewal activity remains largely to be elucidated. In recent years, many types of noncoding RNAs (ncRNAs) have been suggested to regulate the SSC self-renewal through multiple ways, indicating ncRNAs play crucial roles in SSC self-renewal. In this paper, we mainly focus on four types of ncRNAs including microRNA, long ncRNA, piwi-interacting RNA, as well as circular RNAs, and reviewed their potential roles in SSC self-renewal that discovered recently to help us gain a better understanding of molecular mechanisms by which ncRNAs perform their function in regulating SSC self-renewal.

Melatonin promotes goat spermatogonia stem cells (SSCs) proliferation by stimulating glial cell line-derived neurotrophic factor (GDNF) production in Sertoli cells

Melatonin has been reported to be an important endogenous hormone for regulating neurogenesis, immunityand the biological clock. Recently, the effects of melatonin on neural stem cells (NSCs), mesenchymal stem cells(MSCs), and induced pluripotent stem cells(iPSCs) have been reported; however, the effects of melatonin on spermatogonia stem cells (SSCs) are not clear. Here, 1μM and 1nM melatonin was added to medium when goat SSCs were cultured in vitro, the results showed that melatonin could increase the formation and size of SSC colonies. Real-time quantitative PCR (QRT-PCR) and western blot analysis showed that the expression levels of SSC proliferation and self-renewal markers were up-regulated. Meanwhile, QRT-PCR results showed that melatonin inhibit the mRNA expression level of SSC differentiation markers. ELISA analysis showed an obvious increase in the concentration of GDNF (a niche factor secreted by Sertoli cells) in the medium when treated with melatonin. Meanwhile, the phosphorylation level of AKT, a downstream of GDNF-GFRa1-RET pathway was activated. In conclusion, melatonin promotes goat SSC proliferation by stimulating GDNF production in Sertoli cells.

miR-148a and miR-17-5p synergistically regulate milk TAG synthesis via PPARGC1A and PPARA in goat mammary epithelial cells

MicroRNA (miRNA) are a class of '18-25' nt RNA molecules which regulate gene expression and play an important role in several biologic processes including fatty acid metabolism. Here we used S-Poly (T) and high-throughput sequencing to evaluate the expression of miRNA and mRNA during early-lactation and in the non-lactating ("dry") period in goat mammary gland tissue. Results indicated that miR-148a, miR-17-5p, PPARGC1A and PPARA are highly expressed in the goat mammary gland in early-lactation and non-lactating periods. Utilizing a Luciferase reporter assay and Western Blot, PPARA, an important regulator of fatty acid oxidation, and PGC1a (PPARGC1A), a major regulator of fat metabolism, were demonstrated to be targets of miR-148a and miR-17-5p in goat mammary epithelial cells (GMECs). It was also revealed that miR-148a expression can regulate PPARA, and miR-17-5p represses PPARGC1A in GMECs. Furthermore, the overexpression of miR-148a and miR-17-5p promoted triacylglycerol (TAG) synthesis while the knockdown of miR-148a and miR-17-5p impaired TAG synthesis in GMEC. These findings underscore the importance of miR-148a and miR-17-5p as key components in the regulation of TAG synthesis. In addition, miR-148a cooperates with miR-17-5p to regulate fatty acid metabolism by repressing PPARGC1A and PPARA in GMECs. Further studies on the functional role of miRNAs in lipid metabolism of ruminant mammary cells seem warranted.

Lin28a promotes self-renewal and proliferation of dairy goat spermatogonial stem cells (SSCs) through regulation of mTOR and PI3K/AKT

Lin28a is a conserved RNA-binding protein that plays an important role in development, pluripotency, stemness maintenance, proliferation and self-renewal. Early studies showed that Lin28a serves as a marker of spermatogonial stem cells (SSCs) and promotes the proliferation capacity of mouse SSCs. However, there is little information about Lin28a in livestock SSCs. In this study, we cloned Capra hircus Lin28a CDS and found that it is evolutionarily conserved. Lin28a is widely expressed in different tissues of Capra hircus, but is expressed at a high level in the testis. Lin28a is specifically located in the cytoplasm of Capra hircus spermatogonial stem cells and may also be a marker of dairy goat spermatogonial stem cells. Lin28a promoted proliferation and maintained the self-renewal of GmGSCs-I-SB in vivo and in vitro. Lin28a-overexpressing GmGSCs-I-SB showed an enhanced proliferation rate, which might be due to increased PCNA expression. Moreover, Lin28a maintained the self-renewal of GmGSCs-I-SB by up-regulating the expression of OCT4, SOX2, GFRA1, PLZF and ETV5. Furthermore, we found that Lin28a may activate the AKT, ERK, and mTOR signaling pathways to promote the proliferation and maintain the self-renewal of GmGSCs-I-SB.

Genome-wide differential expression of genes and small RNAs in testis of two different porcine breeds and at two different ages

Some documented evidences proved small RNAs (sRNA) and targeted genes are involved in mammalian testicular development and spermatogenesis. However, the detailed molecular regulation mechanisms of them remain largely unknown so far. In this study, we obtained a total of 10,716 mRNAs, 67 miRNAs and 16,953 piRNAs which were differentially expressed between LC and LW pig breeds or between the two sexual maturity stages. Of which, we identified 16 miRNAs and 28 targeted genes possibly related to spermatogenesis; 14 miRNA and 18 targeted genes probably associated with cell adhesion related testis development. We also annotated 579 piRNAs which could potentially regulate cell death, nucleosome organization and other basic biology process, which implied that those piRNAs might be involved in sexual maturation difference. The integrated network analysis results suggested that some differentially expressed genes were involved in spermatogenesis through the ECM-receptor interaction, focal adhesion, Wnt and PI3K-Akt signaling pathways, some particular miRNAs have the negative regulation roles and some special piRNAs have the positive and negative regulation roles in testicular development. Our data provide novel insights into the molecular expression and regulation similarities and diversities of spermatogenesis and testicular development in different pig breeds at different stages of sexual maturity.

CD49f promotes proliferation of male dairy goat germline stem cells

OBJECTIVES

CD49f enhances multipotency and maintains stemness in embryonic stem cells (ESCs), however, whether it would be effective in mGSCs has remained unclear. Moreover, better standards for mGSC enrichment and purification are necessary. The present study was conducted to determine roles of CD49f in mGSC enrichment and regulation.

MATERIALS AND METHODS

CD49f expression patterns were investigated in dairy goats. CD49f positive cells were purified and enriched using magnetic-activated cell sorting (MACS), and characteristics of the cultured cells were assayed using alkaline phosphatase (AP) analysis, quantitative real-time PCR (QRT-PCR) and immunofluorescence analysis. Furthermore, the exogenous CD49f gene was transfected into mGSCs and its effects were analysed.

RESULTS

CD49f was found to be conserved in both mRNA and amino acid sequences and that it was an efficient marker for dairy goat mGSC identification, enrichment and purification. CD49f positive cells expressed higher levels of mGSC-specific markers, and proliferated faster than CD49f negative cells. Overexpression CD49f promoted proliferation of dairy goat mGSCs, and Oct4 expression was upregulated; histone H3-lysine 9 dimethylation (H3K9me2) was reduced.

CONCLUSIONS

Taken together, our data suggest that CD49f plays novel and dynamic roles in regulating maintenance of pluripotency in mGSCs via Oct4 crosstalk and histone methylation dynamics,which may provide new solutions for mGSCs stability in vitro.

miR-204 Regulates the Proliferation of Dairy Goat Spermatogonial Stem Cells via Targeting to Sirt1

The regulation of spermatogonial stem cell (SSC) proliferation and self-renewal is a complex process. Several studies on the microRNA regulation of mammalian spermatogenesis have been reported. Here, we predicted miRNA targeting of Sirt1, and a dual luciferase experiment confirmed that miR-204 interacted with the Sirt1 3'-untranslated region (3'-UTR). The expression of miR-204 and Sirt1 in dairy goat testicles was investigated, and the results showed that the expression pattern of Sirt1 was similar to that of miR-204 in the temporal-spatial distribution. The over-expression of Sirt1 in goat SSCs can promote SSCs' self-renewal gene expression and cell proliferation. Furthermore, miRNA sequencing results showed that Sirt1 had a higher expression level in dairy goat CD49f(+) and CD90(+) SSCs, but the expression level of miR-204 was lower. In an in vitro assay, Sirt1 was significantly down-regulated in dairy goat SSCs when transfected with miR-204 mimics, indicating that Sirt1 was a target of miR-204 in the dairy goat. On the basis of the results of RT-qPCR, fluorescence-activated cell sorting (FACS), and western blotting, we found that the over-expression of Sirt1 in goat SSCs can promote cellular proliferation and change self-renewal and pluripotent gene expression. Thus, miR-204 was involved in the regulation of dairy goat SSCs proliferation via Sirt1.

PLZF-Induced Upregulation of CXCR4 Promotes Dairy Goat Male Germline Stem Cell Proliferation by Targeting Mir146a

Previous studies have shown that promyelocytic leukemia zinc finger (PLZF), chemokine (C-X-C motif) receptor 4 (CXCR4) and mir146a were associated with the self-renewal of mouse spermatogonial stem cells (SSCs); however, there is little information on their effects on the fate of livestock SSCs. Here, we have identified a regulatory pathway in dairy goat mGSCs, involving PLZF, mir146a and the SDF-1 receptor CXCR4. PLZF overexpression downregulated mir146a and simultaneously upregulated the expression of CXCR4 protein, whereas PLZF knockdown (siPLZF) induced the specifically opposite effects. The in vitro assays demonstrated that PLZF specifically interacts with and suppresses the mir146a promoter, and mir146a targets CXCR4 to impede its translation. The levels of ERK1/2 phosphorylation in the mGSCs overexpressed CXCR4 and PLZF were upregulated, respectively, whereas mir146a expression was decreased and CXCR4 protein was increased. Mir146a overexpression and siPLZF impaired mGSC proliferation and differentiation, however, Mir146a knockdown induced the opposite effects. The effects of PLZF and mir146a were mediated regulation by mir146a and CXCR4, respectively. Overexpression of CXCR4 or addition of CXCL12 in cultures of dairy goat mGSCs resulted in the upregulation of their signaling, and the phosphorylation of ERK1/2 was increased. Collectively, these findings indicate that PLZF is an important transcription factor in the regulation of the expression of CXCR4 to promote dairy goat mGSC proliferation by targeting mir146a.

Apparent microRNA-Target-specific Histone Modification in Mammalian Spermatogenesis

BACKGROUND

Epigenetics is an important mRNA expression regulator. However, how distinct epigenetic factors, such as microRNAs (miRNAs) and promoter methylation, cooperatively regulate mRNA expression is rarely discussed. Recently, apparent miRNA regulation of promoter methylation was identified by bioinformatic analysis; however, it has not yet been experimentally confirmed. If miRNA regulation of other epigenetic factors were identified, it would reveal another layer of epigenetic regulation. In this paper, histone modifications (H3K4me1, H3K4me3, H3K27me3, H3K27ac, H3K9ac, and H2AZ) during mammalian spermatogenesis were studied and the apparent miRNA-target-specific histone modification was investigated by bioinformatic analyses of publicly available datasets.

RESULTS

We identified several miRNAs’ target genes that are significantly associated with histone modification during mammalian spermatogenesis. MiRNAs that target genes associated with the most significant histone modifications are expressed before or during spermatogenesis; thus the results were convincing.

CONCLUSIONS

In this paper, we identified apparent miRNA regulation of histone modifications using a bioinformatics approach. The biological mechanisms of this effect should be further experimentally investigated.

PRMT5 enhances generation of induced pluripotent stem cells from dairy goat embryonic fibroblasts via down-regulation of p53

OBJECTIVES

Protein arginine methyltransferase 5 (PRMT5), is thought to play a role in epigenetic reprogramming of mouse germ cells. However, up to now there has been little information concerning its expression profile and effects on generation of induced pluripotent stem cells (iPSCs) from somatic cells, in livestock. Here, we have explored PRMT5 expression profiles in dairy goats and its consequences to derivation of iPSCs from dairy goat embryonic fibroblasts (GEFs).

MATERIALS AND METHODS

We investigated effects of PRMT5 on iPS-like cells production in vitro. alkaline phosphatase (AP) staining, QRT-PCR and western blotting analysis of expression of related markers were used to evaluate efficiency of generation of iPSCs derived from GEFs.

RESULTS

These showed PRMT5 to be a conservative gene widely expressed in various tissues and different-aged testes. PRMT5 overexpression in combination with OCT3/4, SOX2, KLF4 and C-MYC (POSKM) significantly increased number of AP positive iPS-like colony-derived GEFs compared to OSKM alone, in our dairy goats. Moreover, our results demonstrated that PRMT5 overexpression stimulated GEF proliferation and down-regulated p53, p21 (a target gene of p53) and the apoptotic marker caspase 3, to enhance somatic cell reprogramming.

CONCLUSION

This study provides an efficient model for future studies on mechanisms underlying goat somatic cell reprogramming and differentiation.