Small RNAs gained during epididymal transit of sperm are essential for embryonic development in mice
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ABSTRACT: The small RNA payload of mammalian sperm undergoes dramatic remodeling during development, as several waves of microRNAs and tRNA fragments are shipped to sperm during post-testicular maturation in the epididymis. Here, we take advantage of this developmental process to probe the function of the sperm RNA payload in preimplantation development. We generated zygotes via intracytoplasmic sperm injection (ICSI) using sperm obtained from the proximal (caput) vs. distal (cauda) epididymis, then characterized development of the resulting embryos. Embryos generated using caput sperm significantly overexpress multiple regulatory factors throughout preimplantation development, and subsequently implant inefficiently and fail soon after implantation. Remarkably, microinjection of purified cauda-specific small RNAs into caput-derived embryos not only completely rescued preimplantation molecular defects, but also suppressed the postimplantation embryonic lethality phenotype. These findings reveal an essential role for small RNA remodeling during post-testicular maturation of mammalian sperm, and identify a specific preimplantation gene expression program responsive to sperm-delivered microRNAs.
Project description:RNAs present in mature mammalian sperm are delivered to the zygote at fertilization, where they have the potential to affect early development. The biogenesis of the small RNA payload of mature sperm is therefore of great interest, as it may be a target of signaling pathways linking paternal conditions to offspring phenotype. Recent studies have suggested the surprising hypothesis that the small RNA payload carried by mature sperm may include RNAs that were not synthesized during testicular spermatogenesis, but that are instead delivered to sperm during the process of post-testicular maturation in the epididymis. To further test this hypothesis, we characterized small RNA dynamics during testicular and post-testicular germ cell maturation in mice, confirming and extending prior observations that testicular germ cell populations carry extremely low levels of tRNA fragments (tRFs), which only become highly abundant only after sperm have entered the epididymis. We examined the sperm RNA repertoire in greater detail, finding that the majority of 5’ tRNA fragments carry a 2’-3’ cyclic phosphate at their 3’ end, pointing to a role for RNaseA or T-family nucleases in tRNA cleavage in the male reproductive tract. The process of small RNA delivery to sperm can be recapitulated in vitro, as caput epididymosomes deliver small RNAs including tRFs and microRNAs to mature testicular spermatozoa. Finally, to definitively identify the tissue of origin for small RNAs in sperm, we carried out tissue-specific metabolic labeling of RNAs in intact mice, finding that mature sperm carry small RNAs that were originally synthesized in the somatic cells of the epididymis. Taken together, our data demonstrates that soma-germline small RNA transfer occurs in male mammals, most likely via vesicular transport from the epididymis to maturing sperm.
Project description:Epididymosomes are small membrane vesicles (50-500nm) secreted by epididymal epithelial cells and involved in post-testicular sperm maturation. While their role in protein transfer to the sperm membrane is well acknowledged, we unveil here their capacity to vehicle microRNAs (miRNAs), which are potent regulators of post-transcriptional gene expression. Using a global microarray approach, we showed that epididymosomes providing from two discrete bovine epididymal regions (caput and cauda) possess distinct miRNA signatures. In addition, we established that miRNA repertoires contained in epididymosomes differ from those of their parent epithelial cells, suggesting that miRNA populations released from the cells may be selectively sorted. Binding of DilC12-labeled epididymosomes to primary cultured epididymal cells was measured by flow cytometry and indicated that epididymosomes from the median caput and their miRNA content may be incorporated into distal caput epithelial cells. Overall, these findings reveal that distinct miRNA repertoires are released into the intraluminal fluid in a region-specific manner and could be involved in a novel mechanism of intercellular communication throughout the epididymis via epididymosomes. We determined the miRNA profiles of epididymosomes isolated by perfusion from caput and cauda regions of the epididymis and compared it with the miRNA content of epididymal epithelial cells from the same regions.
Project description:Purpose: To compare the transcriptome profiles (RNA-seq) of cultured human epididymis cells and tissue from the caput, corpus and cauda regions of the human epididymis. Methods: Human epididymis tissue was obtained with Institutional Review Board approval from 3 patients (UC05, UC06, UC09, range: 22 - 36 years) undergoing inguinal radical orchiectomy for a clinical diagnosis of testicular cancer. None of the epididymides had extension of the testicular cancer. The three anatomical regions: caput, corpus and cauda, were separated and segments of each snap frozen. Adult human epididymis epithelial (HEE) cultures were also established from tissue. RNA was extracted from both tissue and cultured HEE cells and RNA-seq libraries prepared (TruSeq RNA Sample Preparation Kit v2, Low-Throughput protocol, Illumina). Libraries were sequenced on Illumina HiSeq2500 machines. Data were analyzed using TopHat and Cufflinks. Results: Libraries generated ~19-39 million reads per library from the cells (95-99% mapping to the human genome) and ~14-39 million reads from the tissue samples (84-99% mapped). Raw reads were aligned to the genome with Tophat and gene expression values were processed using Cufflinks as Fragments Per Kilobase per Million mapped fragments (FPKM). FPKM values were subject to principle component analysis, which revealed that though caput, corpus and cauda cell samples respectively from UC05, UC06 and UC09 clustered together. RNA-seq data from the 3 biological replicas (UC05, UC06 and UC09) of caput, corpus and cauda were pooled for further analysis. Cufflinks was used to determine differentially expressed genes (DEGs) between caput, corpus and cauda cells, combined from the 3 donors. The gene expression profiles of corpus and cauda are remarkably similar and both differ from the caput to a similar degree. We identified ~40 genes differentially expressed between corpus and cauda and more than 1600 DEGs between caput and cauda. The DEGs for each comparison (caput and corpus/cauda) were analysed using a gene ontology process enrichment analysis (DAVID, Huang et al., NAR 2009;37:1-13, Huang et al., 2009 Nat Prot 4:44-57). Conclusions: Here we describe an in depth analysis of the gene expression repertoire of primary cultures of epithelial cells and intact tissues from each region of the adult human epididymis. These data will be valuable to decipher pathways of normal epididymis function and aspects of epididymis disease that cause male infertility. RNA-seq was performed on libraries generated from caput, corpus and cauda-derived cultured cells (passage 2 or 3) from 3 donors and on caput, corpus and cauda tissue from 2 of the same donors. Donor age range: 22 - 36 years.
Project description:Following their production in the testis, spermatozoa enter the epididymis to gain their motility and fertilizing abilities. This post-testicular maturation coincides with sperm epigenetic profile changes that influence the progeny outcome. While recent studies underscored the dynamics of small non-coding RNAs in the maturing spermatozoa, little is known regarding sperm methylation changes and their impact at the post-fertilization level. To map out the sperm methylome dynamics, we purified spermatozoa by FACS from the testis and the different epididymal segments (i.e. caput, corpus and cauda) of CAG/su9-DsRed2; Acr3-EGFP transgenic mice. Reduced-Representation Bisulfite Sequencing (RRBS-Seq) performed on DNA from these respective sperm populations indicated that high methylation changes were observed between spermatozoa from the caput vs. testis with 5546 entries meeting our threshold values (q value < 0.01, methylation difference above 25 %). Most of these changes were transitory during epididymal sperm maturation according to the low number of entries identified between spermatozoa from cauda vs. testis.
Project description:Parental dietary conditions can influence the metabolic traits of offspring. In mice, paternal consumption of low protein diet alters cholesterol and lipid metabolism of progeny. Here, we examine RNA species expressed in male reproductive tissues of mice. Protein restriction leads to altered levels of multiple small RNAs in mature sperm, as well as throughout the male reproductive tract, with decreased levels of let-7 family members and increased levels of 5â fragments of tRNA-Gly isoacceptors. Intriguingly, tRNA fragments are scarce in the testis, but their levels increase in sperm during post-testicular maturation in the epididymis. We find that epididymosomes â extracellular vesicles which fuse with sperm during epididymal transit â exhibit RNA payloads closely matching those of mature sperm, and can deliver tRNA fragments to immature sperm in vitro both in mouse and in bull. Finally, we show that tRNA-Gly-GCC fragments play a role in repressing genes associated with the endogenous retroelement MERVL, both in ES cells and in preimplantation embryos. Our results shed light on small RNA biogenesis during post-testicular sperm maturation, and link tRNA fragments to regulation of endogenous retroelements active in the early embryo. Zygotes were generated by ICSI from oocytes/females fed a Control diet and sperm/males fed either a Control or Low Protein diet. The sperm was isolated from either the Rete testis or the Cauda epididymis and injected either as a whole sperm or just the sperm head. Following fertilization by ICSI the zygotes developed for 28 hours (2C stage) and were harvested for single-embryo RNA-Seq.
Project description:Purpose: To compare the transcriptome profiles (RNA-seq) of cultured human epididymis cells and tissue from the caput, corpus and cauda regions of the human epididymis. Methods: Human epididymis tissue was obtained with Institutional Review Board approval from 3 patients (UC05, UC06, UC09, range: 22 - 36 years) undergoing inguinal radical orchiectomy for a clinical diagnosis of testicular cancer. None of the epididymides had extension of the testicular cancer. The three anatomical regions: caput, corpus and cauda, were separated and segments of each snap frozen. Adult human epididymis epithelial (HEE) cultures were also established from tissue. RNA was extracted from both tissue and cultured HEE cells and RNA-seq libraries prepared (TruSeq RNA Sample Preparation Kit v2, Low-Throughput protocol, Illumina). Libraries were sequenced on Illumina HiSeq2500 machines. Data were analyzed using TopHat and Cufflinks. Results: Libraries generated ~19-39 million reads per library from the cells (95-99% mapping to the human genome) and ~14-39 million reads from the tissue samples (84-99% mapped). Raw reads were aligned to the genome with Tophat and gene expression values were processed using Cufflinks as Fragments Per Kilobase per Million mapped fragments (FPKM). FPKM values were subject to principle component analysis, which revealed that though caput, corpus and cauda cell samples respectively from UC05, UC06 and UC09 clustered together. RNA-seq data from the 3 biological replicas (UC05, UC06 and UC09) of caput, corpus and cauda were pooled for further analysis. Cufflinks was used to determine differentially expressed genes (DEGs) between caput, corpus and cauda cells, combined from the 3 donors. The gene expression profiles of corpus and cauda are remarkably similar and both differ from the caput to a similar degree. We identified ~40 genes differentially expressed between corpus and cauda and more than 1600 DEGs between caput and cauda. The DEGs for each comparison (caput and corpus/cauda) were analysed using a gene ontology process enrichment analysis (DAVID, Huang et al., NAR 2009;37:1-13, Huang et al., 2009 Nat Prot 4:44-57). Conclusions: Here we describe an in depth analysis of the gene expression repertoire of primary cultures of epithelial cells and intact tissues from each region of the adult human epididymis. These data will be valuable to decipher pathways of normal epididymis function and aspects of epididymis disease that cause male infertility.
Project description:Purpose: The goal of this study is to detect differentially expressed genes, among Wild type caput, corpus, and cauda epididymis by RNA sequencing Methods: Caput, corpus, and cauda epidiymal mRNA profiles of 9-month-old wild-type mice were generated by deep sequencing, in triplicate, using Illumina GAIIx. Results: RNA-seq data identified transcripts differentially expressed in caput, corpus, and cauda epididymis. Conclusions: Our results show that the expression of many genes were differentially regulated in caput, corpus, and cauda epididymis.
Project description:Epididymosomes are small membrane vesicles (50-500nm) secreted by epididymal epithelial cells and involved in post-testicular sperm maturation. While their role in protein transfer to the sperm membrane is well acknowledged, we unveil here their capacity to vehicle microRNAs (miRNAs), which are potent regulators of post-transcriptional gene expression. Using a global microarray approach, we showed that epididymosomes providing from two discrete bovine epididymal regions (caput and cauda) possess distinct miRNA signatures. In addition, we established that miRNA repertoires contained in epididymosomes differ from those of their parent epithelial cells, suggesting that miRNA populations released from the cells may be selectively sorted. Binding of DilC12-labeled epididymosomes to primary cultured epididymal cells was measured by flow cytometry and indicated that epididymosomes from the median caput and their miRNA content may be incorporated into distal caput epithelial cells. Overall, these findings reveal that distinct miRNA repertoires are released into the intraluminal fluid in a region-specific manner and could be involved in a novel mechanism of intercellular communication throughout the epididymis via epididymosomes.
Project description:We reported the cell composition and segmental expression differences in three epididymis segments using single-cell RNA sequencing. A total of 13,949 cells were detected, which were further clustered into eight cell populations identified with all known constituent cells of mouse epididymis including principle cell, basal cell, clear/narrow cell and immune cells. Through the study of 35 known epididymal proteins linking to sperm function phenotypes (EPSFPs), we found they were mainly expressed in principle cells and also revealed their segmental specific expression patterns. Notably, a part of EPSFPs was associated with sperm protection and predominantly localized in caput principal cells, whereas some EPSFPs, highly expressed in corpus and cauda, were served as the regulating molecular for the sperm functions such as motility, capacitation or acrosome reactions.In addition, focused analyses uncovered 5 subtypes of the principal cell. Intriguingly, Prc5, the subpopulation of principle cells, was almost only existed in the caput epididymis.
Project description:This study investigated the differential responses of the epididymis and testis to infection with uropathogenic Escherichia coli (UPEC) in adult mice. In contrast to the cauda epididymidis, which exhibited ongoing damage following UPEC-infection, spermatogenic disruption was reversible and the caput epididymidis was largely unaffected. The caput epididymidis is structurally and functionally very different from the cauda, whereas beta-defensins as important epididymal antimicrobial factors are highly expressed in both tissues. The transcriptome of the testis, caput, corpus and cauda epididymidis were analysed in normal, wildtype C57BL/6J mice. Distinct differences in gene signatures were observed between caput and cauda epididymidis, particularly among immune-related genes, whereas corpus and cauda were much more alike. Beta-defensins were found at high levels in both caput and cauda epididymidis, whereas other antimicrobial factors, such as Lipocalin 2 and Lypd8 were found expressed selectively high in the caput epididymidis and hence may play an important role in local protection from bacterial pathogens, including UPEC.