A novel testis-specific long noncoding RNA, Tesra, activates the Prss42/Tessp-2 gene during mouse spermatogenesis†

Whole transcriptome analysis identifies differentially expressed mRNA, miRNA and lncRNA associated with male sterility in the silkworm, Bombyx mori

Insect sterility technology is gradually being applied to the control of lepidoptera pests, and the target gene for male sterility is the core of this technology. JMS is a mutant silkworm that exhibits male sterility, and to elucidate its formation mechanism, this study conducted a full transcriptome analysis of the testes of JMS and its wild-type silkworms 48 h after pupation, identifying 205 DElncRNAs, 913 mRNAs, and 92 DEmiRNAs. The KEGG pathway enrichment analysis of the DEmRNAs revealed that they were involved in the biosynthesis of amino acids and ECM-receptor interactions. Combined with ceRNA regulatory network KEGG analysis suggests that pathways from amino acid biosynthesis to hydrolytic processes of protein synthesis may play a crucial role in the formation of JMS mutant variants. Our study deepens our understanding of the regulatory network of male sterility genes in silkworms; it also provides a new perspective for insect sterility technology.

PTBP2 binds to a testis-specific long noncoding RNA, Tesra, and activates transcription of the Prss42/Tessp-2 gene

Long noncoding RNAs (lncRNAs) have recently been proved to be functional in the testis. Tesra, a testis-specific lncRNA, was suggested to activate the transcription of Prss42/Tessp-2, a gene that is involved in meiotic progression, in mouse spermatocytes. To reveal the molecular mechanism underlying the activation, we searched for Tesra-binding proteins by a Ribotrap assay followed by LC-MS/MS analysis and identified polypyrimidine tract binding protein 2 (PTBP2) as a candidate. Analysis of public RNA-seq data and our qRT-PCR results indicated that Ptbp2 mRNA showed an expression pattern similar to the expression patterns of Tesra and Prss42/Tessp-2 during testis development. Moreover, PTBP2 was found to be associated with Tesra in testicular germ cells by RNA immunoprecipitation. To evaluate the effect of PTBP2 on the Prss42/Tessp-2 promoter, we established an in vitro reporter gene assay system in which Tesra expression could be induced by the Tet-on system and thereby Prss42/Tessp-2 promoter activity could be increased. In this system, the Prss42/Tessp-2 promoter activity was significantly decreased by the knockdown of PTBP2. These results suggest that PTBP2 contributes to Prss42/Tessp-2 transcriptional activation by Tesra in spermatocytes. The finding provides a precious example of a molecular mechanism of testis lncRNA functioning in spermatogenesis.

Molecular cloning, expression and cellular localization of two long noncoding RNAs (mLINC-RBE and mLINC-RSAS) in the mouse testis

Long noncoding RNAs (lncRNAs) are transcribed in complex, overlapping, sense- and antisense orientations from intronic and intergenic regions of mammalian genomes. Transcription of genome in mammalian testis is more widespread compared to other organs. LncRNAs are involved in gene expression, chromatin regulation, mRNA stability and translation of proteins during diverse cellular functions. We report molecular cloning of two novel lncRNAs (mLINC-RBE and mLINC-RSAS) and their expression by RT-PCR as well as cellular localization by RNA in-situ hybridization in the mouse testes. mLINC-RBE is an intergenic lncRNA from chromosome 4, with 16.96 % repeat sequences, expressed as a sense transcript with piRNA sequences and its expression is localized into primary spermatocytes. mLINC-RSAS is an intergenic lncRNA from chromosome 2, with 49.7 % repeat sequences, expressed as both sense- and antisense transcripts with miRNA sequences and its expression is localized into different cell types, such as Sertoli cells, primary spermatocytes and round spermatids. The lncRNAs also contain sequences for some short peptides (micropeptides). This suggests that these two repeat sequence containing, intergenic genomic sense- and antisense transcripts expressed as lncRNAs with piRNAs, miRNAs, and showing cell-type specific, differential expression may regulate important functions in mammalian testes. Such functions may be regulated by RNA structures, RNA processing and RNA-protein complexes.

A regulatory mechanism of mouse kallikrein 1 gene expression by estrogen

Tissue kallikrein 1 (Klk1) is a serine protease that degrades several proteins including insulin-like growth factor binding protein-3 and extracellular matrix molecules. Klk1 mRNA expression in the mouse uterus was increased by estradiol-17β (E2). The present study aimed to clarify the regulatory mechanism for Klk1 expression by estrogen. The promoter analysis of the 5'-flanking region of Klk1 showed that the minimal promoter of Klk1 existed in the -136/+24 region, and the estrogen-responsive region in the -433/-136 region. Tamoxifen increased Klk1 mRNA expression and the promoter activity, suggesting the involvement of AP-1 sites. Site-directed mutagenesis for the putative AP-1 sites in the -433/-136 region showed that the two putative AP-1 sites were involved in the regulation of Klk1 expression. Binding of estrogen receptor α (ERα) to the -433/-136 region was revealed by Chip assay. These results indicated that ERα bound the two putative AP-1 sites and transactivated Klk1 in the mouse uterus.

Functions and mechanism of noncoding RNA in regulation and differentiation of male mammalian reproduction

Noncoding RNAs (ncRNAs) are active regulators of a wide range of biological and physiological processes, including the majority of mammalian reproductive events. Knowledge of the biological activities of ncRNAs in the context of mammalian reproduction will allow for a more comprehensive and comparative understanding of male sterility and fertility. In this review, we describe recent advances in ncRNA-mediated control of mammalian reproduction and emphasize the importance of ncRNAs in several aspects of mammalian reproduction, such as germ cell biogenesis and reproductive organ activity. Furthermore, we focus on gene expression regulatory feedback loops including hormones and ncRNA expression to better understand germ cell commitment and reproductive organ function. Finally, this study shows the role of ncRNAs in male reproductive failure and provides suggestions for further research.

Evidence for a functional role of Start, a long noncoding RNA, in mouse spermatocytes

A mouse testis-specific long noncoding RNA (lncRNA), Start, is localized in the cytosol of Leydig cells and in the nucleus of pachytene spermatocytes. We previously showed that Start regulates steroidogenesis through controlling the expression of Star and Hsd3b1 genes in Leydig cells, but its function in germ cells was not known. Here we verified that a spermatocyte-specific protease gene, Prss43/Tessp-3, was downregulated in Start-knockout testes. To investigate the transcriptional regulatory activity of Start in spermatocytes, we first performed a series of reporter gene assays using a thymidine kinase promoter in spermatocyte-derived GC-2spd(ts) cells. A 5.4-kb genome sequence encompassing Start exhibited enhancer activity for this promoter, and the activity was decreased by knockdown of Start. Deletion of the Start promoter and replacement of the Start sequence abolished the enhancer activity and, consistently, the activity was detected in further experiments only when Start was actively transcribed. We then examined whether the Prss43/Tessp-3 gene could be a target of Start. A reporter gene assay demonstrated that the 5.4-kb sequence exhibited enhancer activity for a Prss43/Tessp-3 promoter in GC-2spd(ts) cells and that the activity was significantly decreased by knockdown of Start. These results suggest that Start functions in transcriptional activation of the Prss43/Tessp-3 gene in spermatocytes. Given that Start is presumed to regulate steroidogenic genes at the posttranscriptional level in Leydig cells, the function in spermatocytes is a novel role of Start. These findings provide an insight into multifunctionality of lncRNAs in the testis.

Long Noncoding RNAs: Recent Insights into Their Role in Male Infertility and Their Potential as Biomarkers and Therapeutic Targets

Long noncoding RNAs (lncRNAs) are composed of nucleotides located in the nucleus and cytoplasm; these are transcribed by RNA polymerase II and are greater than 200 nt in length. LncRNAs fulfill important functions in a variety of biological processes, including genome imprinting, cell differentiation, apoptosis, stem cell pluripotency, X chromosome inactivation and nuclear transport. As high throughput sequencing technology develops, a substantial number of lncRNAs have been found to be related to a variety of biological processes, such as development of the testes, maintaining the self-renewal and differentiation of spermatogonial stem cells, and regulating spermatocyte meiosis. These indicate that lncRNAs can be used as biomarkers and potential therapeutic targets for male infertility. However, only a few comprehensive reviews have described the role of lncRNAs in male reproduction. In this paper, we summarize recent findings relating to the role of lncRNAs in spermatogenesis, their potential as biomarkers for male infertility and the relationship between reproductive arrest and transgenerational effects. Finally, we suggest specific targets for the treatment of male infertility from the perspective of lncRNAs.

Transcriptome Analysis of Testicular Aging in Mice

Male reproductive aging, or andropause, is associated with gradual age-related changes in testicular properties, sperm production, and erectile function. The testis, which is the primary male reproductive organ, produces sperm and androgens. To understand the transcriptional changes underlying male reproductive aging, we performed transcriptome analysis of aging testes in mice. A total of 31,386 mRNAs and 9387 long non-coding RNAs (lncRNAs) were identified in the mouse testes of diverse age groups (3, 6, 12, and 18 months old) by total RNA sequencing. Of them, 1571 mRNAs and 715 lncRNAs exhibited changes in their levels during testicular aging. Most of these aging-related transcripts exhibited slight and continuous expression changes during aging, whereas some (9.6%) showed larger expression changes. The aging-related transcripts could be classified into diverse expression patterns, in which the transcripts changed mainly at 3-6 months or at 12-18 months. Our subsequent in silico analysis provided insight into the potential features of testicular aging-related mRNAs and lncRNAs. We identified testis-specific aging-related transcripts (121 mRNAs and 25 lncRNAs) by comparison with a known testis-specific transcript profile, and then predicted the potential reproduction-related functions of the mRNAs. By selecting transcripts that are altered only between 3 and 18 months, we identified 46 mRNAs and 34 lncRNAs that are stringently related to the terminal stage of male reproductive aging. Some of these mRNAs were related to hormonal regulation. Finally, our in silico analysis of the 34 aging-related lncRNAs revealed that they co-localized with 19 testis-expressed protein-coding genes, 13 of which are considered to show testis-specific or -predominant expression. These nearby genes could be potential targets of cis-regulation by the aging-related lncRNAs. Collectively, our results identify a number of testicular aging-related mRNAs and lncRNAs in mice and provide a basis for the future investigation of these transcripts in the context of aging-associated testicular dysfunction.

Non-Coding RNAs: lncRNAs, miRNAs, and piRNAs in Sexual Development

Non-coding RNAs (ncRNAs) are a group of RNAs that do not encode functional proteins, including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), PIWI-interacting RNAs (piRNAs), and short interfering RNAs (siRNAs). In the last 2 decades an effort has been made to uncover the role of ncRNAs during development and disease, and nowadays it is clear that these molecules have a regulatory function in many of the developmental and physiological processes where they have been studied. In this review, we provide an overview of the role of ncRNAs during gonad determination and development, focusing mainly on mammals, although we also provide information from other species, in particular when there is not much information on the function of particular types of ncRNAs during mammalian sexual development.

Testicular germ cell-specific lncRNA, Teshl, is required for complete expression of Y chromosome genes and a normal offspring sex ratio

Heat shock factor 2 (HSF2) regulates the transcription of the male-specific region of the mouse Y chromosome long arm (MSYq) multicopy genes only in testes, but the molecular mechanism underlying this tissue specificity remains largely unknown. Here, we report that the testicular germ cell-specific long noncoding RNA (lncRNA), NR_038002, displays a characteristic spatiotemporal expression pattern in the nuclei of round and elongating spermatids. NR_038002-knockout male mice produced sperm with abnormal head morphology and exhibited reduced fertility accompanied by a female-biased sex ratio in offspring. Molecular analyses revealed that NR_038002 interacts with HSF2 and thereby activates expression of the MSYq genes. We designate NR_038002 as testicular germ cell-specific HSF2-interacting lncRNA (Teshl). Together, our study is the first to demonstrate that the testis specificity of HSF2 activity is regulated by the lncRNA Teshl and establishes a Teshl-HSF2-MSYq molecular axis for normal Y-bearing sperm qualities and consequent balanced offspring sex ratio.

A panel of extracellular vesicle long noncoding RNAs in seminal plasma for predicting testicular spermatozoa in nonobstructive azoospermia patients

STUDY QUESTION

Whether the testis-specific extracellular vesicle (EV) long noncoding RNAs (lncRNAs) in seminal plasma could be utilized to predict the presence of testicular spermatozoa in nonobstructive azoospermia (NOA) patients?

SUMMARY ANSWER

Our findings indicate that the panel based on seminal plasma EV lncRNAs was a sensitive and specific method in predicting the presence of testicular spermatozoa and may improve clinical decision-making of NOA.

WHAT IS KNOWN ALREADY

The adoption of sperm retrieval techniques, especially microdissection testicular sperm extraction (mTESE), in combination with ICSI has revolutionized treatment for NOA. However, there are no precise and noninvasive methods for predicting whether there are testicular spermatozoa in NOA patients before mTESE.

STUDY DESIGN, SIZE, DURATION

RNA sequencing was performed on seminal plasma EVs from 6 normozoospermic men who underwent IVF due to female factor and 5 idiopathic NOA patients who failed to obtain testicular spermatozoa by mTESE and were diagnosed as having Sertoli cell-only syndrome by postoperative pathology. A biomarker panel of lncRNAs was constructed and verified in 96 NOA patients who underwent mTESE. Decision-making process was established based on the panel in seminal plasma EVs from 45 normozoospermia samples, 43 oligozoospermia samples, 62 cryptozoospermia samples, 96 NOA samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RNA sequencing was done to examine altered profiles of EV lncRNAs in seminal plasma. Furthermore, a panel consisting of EV lncRNAs was established and evaluated in training set and validation sets.

MAIN RESULTS AND THE ROLE OF CHANCE

A panel consisting of nine differentially expressed testis-specific lncRNAs, including LOC100505685, SPATA42, CCDC37-DT, GABRG3-AS1, LOC440934, LOC101929088 (XR_927561.2), LOC101929088 (XR_001745218.1), LINC00343 and LINC00301, was established in the training set and the AUC was 0.986. Furthermore, the AUC in the validation set was 0.960. Importantly, the panel had a unique advantage when compared with models based on serum hormones from the same group of NOA cases (AUC, 0.970 vs 0.723; 0.959 vs 0.687, respectively). According to the panel of lncRNAs, a decision-making process was established, that is when the score of an NOA case exceeds 0.532, sperm retrieval surgery may be recommended.

LIMITATIONS, REASONS FOR CAUTION

In the future, the sample size needs to be further expanded. Meanwhile, the regulatory functions and mechanism of lncRNAs in spermatogenesis also need to be elucidated.

WIDER IMPLICATIONS OF THE FINDINGS

When the score of our panel is below 0.532, subjecting the NOA patients to ineffective surgical interventions may not be recommended due to poor sperm retrieval rate.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (81871110, 81971314 and 81971759); the Guangdong Special Support Plan-Science and Technology Innovation Youth Top Talents Project (2016TQ03R444); the Science and Technology Planning Project of Guangdong Province (2016B030230001 and 201707010394); the Key Scientific and Technological Program of Guangzhou City (201604020189); the Pearl River S&T Nova Program of Guangzhou (201806010089); the Transformation of Scientific and Technological Achievements Project of Sun Yat-sen University (80000-18843235) and the Youth Teacher Training Project of Sun Yat-sen University (17ykpy68 and 18ykpy09). There are no competing interests related to this study.

TRIAL REGISTRATION NUMBER

N/A.

Transcriptomics of Meiosis in the Male Mouse

Molecular studies of meiosis in mammals have been long relegated due to some intrinsic obstacles, namely the impossibility to reproduce the process in vitro, and the difficulty to obtain highly pure isolated cells of the different meiotic stages. In the recent years, some technical advances, from the improvement of flow cytometry sorting protocols to single-cell RNAseq, are enabling to profile the transcriptome and its fluctuations along the meiotic process. In this mini-review we will outline the diverse methodological approaches that have been employed, and some of the main findings that have started to arise from these studies. As for practical reasons most studies have been carried out in males, and mostly using mouse as a model, our focus will be on murine male meiosis, although also including specific comments about humans. Particularly, we will center on the controversy about gene expression during early meiotic prophase; the widespread existing gap between transcription and translation in meiotic cells; the expression patterns and potential roles of meiotic long non-coding RNAs; and the visualization of meiotic sex chromosome inactivation from the RNAseq perspective.

Silencing of MEG3 attenuated the role of lipopolysaccharides by modulating the miR-93-5p/PTEN pathway in Leydig cells

BACKGROUND

Leydig cells reflect the activation of inflammation, decrease of androgen production, inhibition of cell growth and promotion of cell apoptosis under orchitis. Maternally expressed gene 3 (MEG3) exerts a crucial role in various human diseases, but under orchitis, the role and underlying molecular mechanism of MEG3 in Leydig cells remain unclear.

METHODS

Lipofectamine 2000 was used for the cell transfections. qPCR and western blots assay were applied to assess the gene expression. ELISA assay was used to measure the TNFα, IL6 and testosterone secretion. CCK8 and EdU assay was employ to test the cell viability and proliferation respectively. Luciferase reporter and RIP assay were introduced to detect the binding of miR-93-5p with MEG3 and PTEN.

RESULTS

Lipopolysaccharides (LPS) induced TNFα and IL6 secretion, lowered testosterone production, inhibited cell viability and proliferation, and induced cell apoptosis in Leydig cells. MEG3 was upregulated in Leydig cells treated with LPS and that knockdown of MEG3 inhibited the role of LPS in Leydig cells. MEG3 absorbed miR-93-5p and that suppression of miR-93-5p restored the role of silenced MEG3 in Leydig cells under LPS treatment. miR-93-5p inhibited PTEN expression and that over-expressed PTEN alleviated the effect of miR-93-5p in Leydig cells treated with LPS. LPS activated the MEG3/miR-93-5p/PTEN signalling pathway in Leydig cells.

CONCLUSIONS

This study revealed that MEG3 serves as a molecular sponge to absorb miR-93-5p, thus leading to elevation of PTEN expression in Leydig cells under LPS treatment, offering a theoretical basis on which to establish potential new treatment strategies for orchitis.

A Testis-Specific Long Noncoding RNA, Start, Is a Regulator of Steroidogenesis in Mouse Leydig Cells

The testis expresses many long noncoding RNAs (lncRNAs), but their functions and overview of lncRNA variety are not well understood. The mouse Prss/Tessp locus contains six serine protease genes and two lncRNAs that have been suggested to play important roles in spermatogenesis. Here, we found a novel testis-specific lncRNA, Start (Steroidogenesis activating lncRNA in testis), in this locus. Start is 1822 nucleotides in length and was found to be localized mostly in the cytosol of germ cells and Leydig cells, although nuclear localization was also observed. Start-knockout (KO) mice generated by the CRISPR/Cas9 system were fertile and showed no morphological abnormality in adults. However, in adult Start-KO testes, RNA-seq and qRT-PCR analyses revealed an increase in the expression of steroidogenic genes such as Star and Hsd3b1, while ELISA analysis revealed that the testosterone levels in serum and testis were significantly low. Interestingly, at 8 days postpartum, both steroidogenic gene expression and testosterone level were decreased in Start-KO mice. Since overexpression of Start in two Leydig-derived cell lines resulted in elevation of the expression of steroidogenic genes including Star and Hsd3b1, Start is likely to be involved in their upregulation. The increase in expression of steroidogenic genes in adult Start-KO testes might be caused by a secondary effect via the androgen receptor autocrine pathway or the hypothalamus-pituitary-gonadal axis. Additionally, we observed a reduced number of Leydig cells at 8 days postpartum. Collectively, our results strongly suggest that Start is a regulator of steroidogenesis in Leydig cells. The current study provides an insight into the overall picture of the function of testis lncRNAs.

Long non-coding RNAs (lncRNAs) in spermatogenesis and male infertility

BACKGROUND

Long non-coding RNAs (lncRNAs) have a size of more than 200 bp and are known to regulate a host of crucial cellular processes like proliferation, differentiation and apoptosis by regulating gene expression. While small noncoding RNAs (ncRNAs) such as miRNAs, siRNAs, Piwi-interacting RNAs have been extensively studied in male germ cell development, the role of lncRNAs in spermatogenesis remains largely unknown.

OBJECTIVE

In this article, we have reviewed the biology and role of lncRNAs in spermatogenesis along with the tools available for data analysis.

RESULTS AND CONCLUSIONS

Till date, three microarray and four RNA-seq studies have been undertaken to identify lncRNAs in mouse testes or germ cells. These studies were done on pre-natal, post-natal, adult testis, and different germ cells to identify lncRNAs regulating spermatogenesis. In case of humans, five RNA-seq studies on different germ cell populations, including two on sperm, were undertaken. We compared three studies on human germ cells to identify common lncRNAs and found 15 lncRNAs (LINC00635, LINC00521, LINC00174, LINC00654, LINC00710, LINC00226, LINC00326, LINC00494, LINC00535, LINC00616, LINC00662, LINC00668, LINC00467, LINC00608, and LINC00658) to show consistent differential expression across these studies. Some of the targets of these lncRNAs included CENPB, FAM98B, GOLGA6 family, RPGR, TPM2, GNB5, KCNQ10T1, TAZ, LIN28A, CDKN2B, CDKN2A, CDKN1A, CDKN1B, CDKN1C, EZH2, SUZ12, VEGFA genes. A lone study on human male infertility identified 9879 differentially expressed lncRNAs with three (lnc32058, lnc09522, and lnc98497) of them showing specific and high expression in immotile sperm in comparison to normal motile sperm. A few lncRNAs (Mrhl, Drm, Spga-lncRNAs, NLC1-C, HongrES2, Tsx, LncRNA-tcam1, Tug1, Tesra, AK015322, Gm2044, and LncRNA033862) have been functionally validated for their roles in spermatogenesis. Apart from rodents and humans, studies on sheep and bull have also identified lncRNAs potentially important for spermatogenesis. A number of these non-coding RNAs are strong candidates for further research on their roles in spermatogenesis.

Transcriptional activation of the mouse Scd2 gene by interdependent enhancers and long noncoding RNAs in ovarian granulosa cells

Specific gene expression in granulosa cells is key for the function of ovary, but the molecular mechanism of transcriptional activation is not well studied. Here we investigated the regulatory mechanism of the mouse stearoyl-CoA desaturase 2 (Scd2) gene encoding an enzyme for lipid metabolism. Northern blot and in situ hybridization indicated that the mouse Scd2 mRNA was highly expressed in ovarian granulosa cells. We found four conserved noncoding sequences (CNSs) and two long noncoding RNAs (lncRNAs) transcribed from regions upstream of the Scd2 gene as candidates of regulatory elements/factors. These lncRNAs were predominantly transcribed in the opposite direction to Scd2 and localized in nuclei and showed the correlation with Scd2 expression, raising the possibility of their transcriptional regulatory roles. Indeed, knockdown of both lncRNAs, lncRNA-sc1 and lncRNA-sc2, significantly decreased the Scd2 mRNA level in primary granulosa cells. Then, we investigated the histone modification pattern at this locus by a chromatin immunoprecipitation assay, and two CNSs, CNS1 and CNS2, were found to be marked with high levels of histone H3K9/K27 acetylation in primary granulosa cells. By a reporter gene assay, both CNS1 and CNS2 interdependently exhibited enhancer activity for the Scd2 promoter in primary granulosa cells. These data suggest that the mouse Scd2 gene is activated by two lncRNAs and interdependent enhancers in ovarian granulosa cells, which provides a new insight into transcriptional activation in granulosa cells.

Long noncoding RNAs: new insights in modulating mammalian spermatogenesis

Spermatogenesis is a complex differentiating developmental process in which undifferentiated spermatogonial germ cells differentiate into spermatocytes, spermatids, and finally, to mature spermatozoa. This multistage developmental process of spermatogenesis involves the expression of many male germ cell-specific long noncoding RNAs (lncRNAs) and highly regulated and specific gene expression. LncRNAs are a recently discovered large class of noncoding cellular transcripts that are still relatively unexplored. Only a few of them have post-meiotic; however, lncRNAs are involved in many cellular biological processes. The expression of lncRNAs is biologically relevant in the highly dynamic and complex program of spermatogenesis and has become a research focus in recent genome studies. This review considers the important roles and novel regulatory functions whereby lncRNAs modulate mammalian spermatogenesis.

Functions and mechanism of noncoding RNA in the somatic cells of the testis

ncRNAs are involved in numerous biological processes by regulating gene expression and cell stability. Studies have shown that ncRNAs also contribute to spermatogenesis. Leydig cells (LCs) and Sertoli cells (SCs) are somatic cells of the testis that support spermatogenesis and are vital to male fertility. In this review, we summarized the findings from studies on ncRNAs in SCs and LCs. In SCs, ncRNAs play key roles in phagocytosis, immunoprotection and development of SCs. In LCs, ncRNAs are involved in steroidogenesis, in particular production of testosterone as well as development of LCs. Here, we discuss the possible target genes and functions of ncRNAs in both types of cells. These ncRNAs regulate the expression of target genes or mRNA coding sequence regions, resulting in a chain reaction that influences cell function. In addition, microRNAs, lncRNAs, piRNA-like RNAs (pilRNAs) and natural antisense transcripts (NATs) are discussed in this review. In summary, we suggest that these ncRNAs might act in coordination to control spermatogenesis and maintain the environmental homeostasis of the testis.