Translational regulation of a novel testis-specific RNF4 transcript

Testicular/paratesticular mesothelial tumours: Uncommon histopathologic entities in a very complex anatomical site

Mesothelial tumours of the testicular/paratesticular region are uncommon, poorly characterised and difficult-to-diagnose lesions. They encompass entirely benign proliferations (adenomatoid tumour) and malignant, very aggressive tumours (mesothelioma) whose morphological features can be overlapping, highly variable and confounding. Moreover, testicular/paratesticular mesothelial tumours comprise relatively new entities with indolent behaviour (well-differentiated papillary mesothelial tumour) as well as tumours which cannot be correctly included in any of the aforementioned categories and whose classification is still controversial. The molecular profile of such tumours represents an open issue. In fact, despite the recent discoveries about the genomic landscape of mesothelial proliferations at other sites (pleura, peritoneum), testicular/paratesticular mesothelial tumours, and namely mesotheliomas, are too rare to be extensively studied on large case series and they could arguably hide relevant differences in their molecular background when compared to the more common pleural/peritoneal counterparts.The aim of this review is to provide a guide for the pathological assessment of testicular/paratesticular mesothelial tumours. Herein, we describe the most recent updates on this topic according to the latest (year 2022) World Health Organisation Classification of Urinary and Male Genital Tumours (5th edition) and current literature. The diagnostic criteria, the main differentials and the role of ancillary techniques in the diagnosis of mesothelial testicular/paratesticular tumours are discussed.

Drug-induced inhibition of HMGA and EZH2 activity as a possible therapy for anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and lethal neoplasms in humans, and just limited progresses have been made to extend patient survival and decrease ATC-associated mortality. Thus, the identification of novel therapeutic strategies for treating ATC is needed. Recently, our group has identified two proteins with oncogenic activity, namely HMGA1 and EZH2, with pivotal roles in ATC cancer progression. Therefore, we tested the ability of trabectedin, a HMGA1-targeting drug, and GSK126, an inhibitor of EZH2 enzymatic activity, to impair cell viability of four ATC-derived cell lines. In the present study, we first confirmed the overexpression of HMGA1 and EZH2 in all ATC-derived cell lines and tissues compared to the normal primary thyroid cells and tissues. Then, treatment of the ATC cell lines with trabectedin and GSK126 resulted in a drastic induction of apoptotic cell death, which increased when the ATC cell lines were treated with a combination of both drugs. Conversely, normal primary human thyroid cells did not show any significant reduction in their viability when exposed to the same drugs. Noteworthy, both drugs induced the deregulation of EZH2- and HMGA1-controlled genes. Altogether, these findings propose the combination of trabectedin and GSK126 as possible novel strategy for ATC therapy.

Analysis of microsatellite instability (MSI) in pediatric gonadal and extra-gonadal germ cell tumors

Gonadal and extragonadal pediatric germ cell tumors (GCTs) are rare neoplasms with different clinical behavior. Although surgery and cisplatin-based chemotherapy are resolutive in most cases, some patients do not respond to chemotherapy and have a worse outcome. Microsatellite instability (MSI) was correlated to resistance to chemotherapy and sensitivity to immunotherapy in different neoplasms. A series of 21 pediatric GCTs were tested by immuno-histochemistry and PCR to evaluate MSI status. Next generation sequencing was applied to further evaluate cases with discordant results between immunohistochemistry and PCR. Twenty-one cases of pediatric GCT were included in the series. The mean age ranged between 1 and 10 years. Nine cases were gonadal GCTs and the remaining 12 were extra-gonadal GCTs. By immunohistochemistry, one case showed a deficit of Mismatch repair (MMR) proteins. This case was a 1-year-old children affected by gonadal yolk sac tumor. However, all cases resulted microsatellite stable (MSS) by PCR and NGS. MSI was not detected in our series of pediatric GCTs, as well as the data present in literature about adult patients with GCTs. Molecular techniques could have a role to confirm the MSI status in case of dMMR by immunohistochemistry.

Potential biomarkers for testicular germ cell tumour: Risk assessment, diagnostic, prognostic and monitoring of recurrence

Testicular germ cell tumour (TGCT) is considered a relatively rare malignancy usually occurring in young men between 15 and 35 years of age, and both genetic and environmental factors contribute to its development. The majority of patients are diagnosed in an early-stage of TGCTs with an elevated 5-year survival rate after therapy. However, approximately 25% of patients show an incomplete response to chemotherapy or tumours relapse. The current therapies are accompanied by several adverse effects, including infertility. Aside from classical serum biomarker, many studies reported novel biomarkers for TGCTs, but without proper validation. Cancer cells share many similarities with embryonic stem cells (ESCs), and since ESC genes are not transcribed in most adult tissues, they could be considered ideal candidate targets for cancer-specific diagnosis and treatment. Added to this, several microRNAs (miRNA) including miRNA-371-3p can be further investigated as a molecular biomarker for diagnosis and monitoring of TGCTs. In this review, we will illustrate the findings of recent investigations in novel TGCTs biomarkers applicable for risk assessment, screening, diagnosis, prognosis, prediction and monitoring of the relapse.

miRNAs and Biomarkers in Testicular Germ Cell Tumors: An Update

Testicular germ cell tumors (TGCTs) are the leading form of solid cancer and death affecting males between the ages of 20 and 40. Today, their surgical resection and chemotherapy are the treatments of first choice, even if sometimes this is not enough to save the lives of patients with TGCT. As seen for several tumors, the deregulation of microRNAs (miRNAs) is also a key feature in TGCTs. miRNAs are small molecules of RNA with biological activity that are released into biological fluids by testicular cancer cells. Their presence, therefore, can be detected and monitored by considering miRNAs as diagnostic and prognostic markers for TGCTs. The purpose of this review is to collect all the studies executed on miRNAs that have a potential role as biomarkers for testicular tumors.

An update on microRNAs as potential novel therapeutic targets in testicular germ cell tumors

Testicular germ cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20- 40 years of age and the most frequent cause of death from solid tumors in this age group. Recent studies have underscored the fact that miRNA deregulation is a feature of carcinogenesis, including TGCT development and progression. MiRNAs are a group of small noncoding RNAs that bind to the 3'-untranslated region (UTR) of the targeted mRNAs, thus causing mRNA degradation or the inhibition of its translation, regulating gene expression in a temporal and tissue-specific manner. However, few miRNAs have been found to play key roles in TGCTs; recently, other miRNAs have been identified, representing novel potential therapeutic targets.

An up-date on novel molecular targets in testicular germ cell tumors subtypes

Testicular germ cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20-34 years of age and the most frequent cause of death from solid tumors in this age group. In addition, the incidence of these tumors has significantly increased over the last few decades. Testicular germ cell tumors are classified into seminoma and nonseminoma germ cell tumors (NSGCTs). NSGCTs can be further divided into embryonal carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. There are noteworthy differences about therapy and prognosis of seminomas and nonseminoma germ cell tumors, even though both share characteristics of the primordial germ cells (PGCs). Many discovered biomarkers including HMGA1, GPR30, Aurora-B, estrogen receptor β, and others have given further advantage to discriminate between histological subgroups and could represent useful molecular therapeutic targets.

New Anti-Cancer Strategies in Testicular Germ Cell Tumors

Methods:

Bibliographic data from peer-reviewed research, patent and clinical trial literature, and around eighty papers and patents have been included in this review.

Results:

Our study reveals that several biomarkers are usefully utilized to discriminate among different histotypes. Moreover, we found new patents regarding testicular germ cell tumor treatments such as the expression of claudin 6, monoclonal antibody (Brentuximab Vedotin), immune checkpoint blockade (ICB) with the FDA-approved drugs pembrolizumab and nivolumab or the oncolytic virus Pelareorep, the combination of selective inhibitors of Aurora kinase.

Conclusion:

Finally, the pathogenesis of testicular germ cell tumor needs to be deeply understood so that it will improve data on stem cells, tumorigenesis and disease tumor management by more selective treatment.

H2AFZ, RNF4 and NR4A1 loci are associated with boar semen quality by population association studies

Spermatogenesis is a complex process regulated by many genes. In this study, H2AFZ, RNF4 and NR4A1 genes were selected as candidate genes for boar semen quality traits based on their functions during spermatogenesis, and the associations of three loci (H2AFZ c.192 + 210-192 + 213delCGAT, RNF4 c.374 + 358 T > C and NR4A1 c.956 + 796 A > G) with sperm quality traits were analyzed in Duroc (n = 185), Large White (n = 87) and Landrace (n = 49) pig populations. The results showed H2AFZ c.192 + 210-192 + 213delCGAT AA boars produced 1.52% lower abnormal sperm rate (ASR) than AB boars in Landrace pigs (p < 0.05); RNF4 c.374 + 358 TC boars produced 0.31 × 10⁸/ml higher sperm concentration (SCON) than CC boars (p < 0.05) in Large White pigs; NR4A1 c.956 + 796 A > G was associated with ASR in Duroc and Large White pigs and was associated with sperm motility (MOT) in Large White and Landrace pigs. This study indicated the H2AFZ, RNF4 and NR4A1 loci were the potential molecular markers for improving the semen quality traits in boars.

Aurora B: A new promising therapeutic target in cancer

A critical step for maintenance of genetic stability is chromosome segregation, which requires a high coordination of cellular processes. Loss of mitotic regulation is a possible cause of aneuploidy in human epithelial malignancy and it is thought to create an abnormal nuclear morphology in cancer cells. Serine/threonine protein kinase Aurora B gene plays a regulatory role from G2 to cytokinesis, encompassing key cell cycle events such as centrosome duplication, chromosome bi-orientation, and segregation. The overexpression of Aurora B has been observed in several tumour types, and has been linked with a poor prognosis for cancer patients. Therapeutic inhibition of Aurora kinase showed great promise as a probable anticancer regime because of its important role during cell division.

An up-date on epigenetic and molecular markers in testicular germ cell tumors

Testicular germ cell tumor (TGCT) is the most common solid malignancy occurring in young men between 20 and 34 years of age, and its incidence has increased significantly over the last decades. Clinically several types of immunohistochemical markers are useful and sensitive. These new biomarkers are genes expressed in primordial germ cells/gonocytes and embryonic pluripotency-related cells but not in normal adult germ cells and they include OCT3/4, HMGA1 and 2, NANOG, SOX2, and LIN28. Gene expression in TGCT is regulated, at least in part, by DNA and histone modifications, and the epigenetic profile of these tumours is characterised by genome-wide demethylation. There are different epigenetic modifications in TGCT subtypes that reflect the normal developmental switch in primordial germ cells from an under to normally methylated genome.

Will Testicular Germ Cell Tumors Remain Untargetable?

Testicular Germ cell tumors (TGCT) represent the most common solid tumors affecting young men. They constitute a distinct entity because of their embryonic origin and their unique biological behavior. Recently, new preclinical data on genetic and epigenetic susceptibility profiles, biological signaling machinery as well as on molecular patterns of tumors and pathways of pathogenesis helped to elucidate the pathogenesis and the differentiation of TGCTs and to understand the mechanisms behind the development of resistance to treatment. In the present work, we have reviewed new clues to the development, differentiation and progression of TGCTs. We focus on the most important epigenetic and molecular biomarkers, and discussed their diagnostic and prognostic accuracy compared to the currently used biomarkers. The mechanisms underlying the development of resistance to cisplatin and commonly used chemotherapeutic agents are also discussed in detail. Finally, we summarize failed and ongoing clinical trials using targeted therapies in resistant TGCTs, and analyze the potential of new targeted therapies.

Testicular cancer from diagnosis to epigenetic factors

Testicular cancer (TC) is one of the most common neoplasms that occurs in male and includes germ cell tumors (GCT), sex cord-gonadal stromal tumors and secondary testicular tumors. Diagnosis of TC involves the evaluation of serum tumor markers alpha-fetoprotein, human chorionic gonadotropin and lactate dehydrogenase, but clinically several types of immunohistochemical markers are more useful and more sensitive in GCT, but not in teratoma. These new biomarkers are genes expressed in primordial germ cells/gonocytes and embryonic pluripotency-related cells but not in normal adult germ cells and they include PLAP, OCT3/4 (POU5F1), NANOG, SOX2, REX1, AP-2γ (TFAP2C) and LIN28. Gene expression in GCT is regulated, at least in part, by DNA and histone modifications, and the epigenetic profile of these tumours is characterised by genome-wide demethylation. There are different epigenetic modifications in TG-subtypes that reflect the normal developmental switch in primordial germ cells from an under- to normally methylated genome. The main purpose of this review is to illustrate the findings of recent investigations in the classification of male genital organs, the discoveries in the use of prognostic and diagnostic markers and the epigenetic aberrations mainly affecting the patterns of DNA methylation/histone modifications of genes (especially tumor suppressors) and microRNAs (miRNAs).

RNA decay, evolution, and the testis

NMD is a highly conserved pathway that degrades specific subsets of RNAs. There is increasing evidence for roles of NMD in development. In this commentary, we focus on spermatogenesis, a process dramatically impeded upon loss or disruption of NMD. NMD requires strict regulation for normal spermatogenesis, as loss of a newly discovered NMD repressor, UPF3A, also causes spermatogenic defects, most prominently during meiosis. We discuss the unusual evolution of UPF3A, whose paralog, UPF3B, has the opposite biochemical function and acts in brain development. We also discuss the regulation of NMD during germ cell development, including in chromatoid bodies, which are specifically found in haploid germ cells. The ability of NMD to coordinately degrade batteries of RNAs in a regulated fashion during development is akin to the action of transcriptional pathways, yet has the advantage of driving rapid changes in gene expression.

Chromatoid Body Protein TDRD6 Supports Long 3' UTR Triggered Nonsense Mediated mRNA Decay

Chromatoid bodies (CBs) are spermiogenesis-specific organelles of largely unknown function. CBs harbor various RNA species, RNA-associated proteins and proteins of the tudor domain family like TDRD6, which is required for a proper CB architecture. Proteome analysis of purified CBs revealed components of the nonsense-mediated mRNA decay (NMD) machinery including UPF1. TDRD6 is essential for UPF1 localization to CBs, for UPF1-UPF2 and UPF1-MVH interactions. Upon removal of TDRD6, the association of several mRNAs with UPF1 and UPF2 is disturbed, and the long 3’ UTR-stimulated but not the downstream exon-exon junction triggered pathway of NMD is impaired. Reduced association of the long 3’ UTR mRNAs with UPF1 and UPF2 correlates with increased stability and enhanced translational activity. Thus, we identified TDRD6 within CBs as required for mRNA degradation, specifically the extended 3’ UTR-triggered NMD pathway, and provide evidence for the requirement of NMD in spermiogenesis. This function depends on TDRD6-promoted assembly of mRNA and decay enzymes in CBs.

Tudor-domain containing protein 6 (TDRD6) is a central component of the chromatoid body (CB) in male germ cells. Chromatoid bodies, which are present in spermatids, contain RNA and protein, are not enclosed by membranes, and typically reside close to the nucleus. Without TDRD6, a much distorted CB structure is observed, and this work asked for the functional contribution of TDRD6 to spermatids. We found that TDRD6 is required for localization of an RNA degradation machinery to the CB. This so-called nonsense mediated decay (NMD) machinery, known from somatic cells, destroys mRNAs that feature premature stop codons. Absence of TDRD6 significantly impairs one specific mechanism of NMD, which depends on long 3’ untranslated regions of the transcripts. Thus, the CB component TDRD6 acts in the assembly of the NMD machinery in the CB.

New perspective on molecular markers as promising therapeutic targets in germ cell tumors

Testicular germ cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20-40 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs comprise two major histologic groups: seminomas and non-seminomas germ cell tumors (NSGCTs). NSGCTs can be further divided into embryonal carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. Seminomas and NSGCTs present significant differences in clinical features, therapy, and prognosis, and both show characteristics of the Primordial Germ Cells (PGCs). Many discovered biomarkers including HMGA1, GPR30, Aurora-B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups and could represent useful therapeutic targets.

Roles of RNA-binding Proteins and Post-transcriptional Regulation in Driving Male Germ Cell Development in the Mouse

Tissue development and homeostasis are dependent on highly regulated gene expression programs in which cell-specific combinations of regulatory factors determine which genes are expressed and the post-transcriptional fate of the resulting RNA transcripts. Post-transcriptional regulation of gene expression by RNA-binding proteins has critical roles in tissue development-allowing individual genes to generate multiple RNA and protein products, and the timing, location, and abundance of protein synthesis to be finely controlled. Extensive post-transcriptional regulation occurs during mammalian gametogenesis, including high levels of alternative mRNA expression, stage-specific expression of mRNA variants, broad translational repression, and stage-specific activation of mRNA translation. In this chapter, an overview of the roles of RNA-binding proteins and the importance of post-transcriptional regulation in male germ cell development in the mouse is presented.

High levels of GPR30 protein in human testicular carcinoma in situ and seminomas correlate with low levels of estrogen receptor-beta and indicate a switch in estrogen responsiveness

The G protein-coupled estrogen receptor (GPR30) is suggested to be involved in non-nuclear estrogen signalling and is expressed in a variety of hormone dependent cancer entities. It is well established that oestrogens are involved in pathological germ cell proliferation including testicular germ cell tumours. This study was performed to further elucidate the role of this receptor and the possible correlation with the estrogen receptor β in human testicular carcinoma in situ (CIS), seminomas and in GC1 and TCam-2 germ cell lines; in addition, a Tissue Micro-Array was built using the most representative areas from 25 cases of human testicular seminomas and 20 cases of CIS. The expression of ERβ and GPR30 were observed by using Western blot analysis in combination with immunocytochemistry and immunofluorescence analyses. Here, we show that down regulation of ERβ associates with GPR30 over-expression both in human testicular CIS and seminomas. In addition, we show that 17β-oestradiol induces the ERK1/2 activation and increases c-Fos expression through GPR30 associated with ERβ down-regulation in TCam-2 cell line. The present results suggest that exposure to oestrogens or oestrogen-mimics, in some as of yet undefined manner, diminishes the ERβ-mediated growth restraint in CIS and in human testicular seminoma, probably due to ERβ down-regulation associated to GPR30 increased expression indicating that GPR30 could be a potential therapeutic target to design specific inhibitors.

Recent advances in molecular and cell biology of testicular germ-cell tumors

Testicular germ-cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20-40 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs comprise two major histologic groups: seminomas and nonseminomas germ-cell tumors (NSGCTs). NSGCTs can be further divided into embryonal, carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. Seminomas and NSGCTs present significant differences in clinical features, therapy, and prognosis, and both show characteristics of the primordial germ cells. Many discovered biomarkers including OCT3/4, SOX2, SOX17, HMGA1, Nek2, GPR30, Aurora-B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups and could represent useful novel molecular targets for antineoplastic strategies. More insight into the pathogenesis of TGCTs is likely to improve disease management not only to better treatment of these tumors but also to a better understanding of stem cells and oncogenesis.

Molecular biomarkers as potential targets for therapeutic strategies in human testicular germ cell tumors: an overview

Testicular germ cell tumors (TGCTs), the most common malignancy in males between 15 and 34 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs can be subdivided into seminoma and non-seminoma germ cell tumors (NSGCTs), including embryonal cell carcinoma, choriocarcinoma, yolk sac tumor, and teratoma. Seminomas and NSGCTs do not only present distinctive clinical features, but they also show significant differences as far as therapy and prognosis are concerned. Seminomas are highly sensitive to both radiation and chemotherapy, with a good prognosis, non-seminomas are sensitive to platinum-based combination chemotherapy and are less susceptible to radiation, with the exception of teratomas. The different therapeutic outcome might be explained by inherent properties of the cells from which testicular neoplasia originate. The unique treatment sensitivity of TGCTs is unexplained so far, but it is likely to be related to intrinsic molecular characteristics of the PGCs/gonocytes, from which these tumors originate. Many discovered bio-markers including OCT3/4, SOX2, SOX17, HMGA1, HMGA2, PATZ1, GPR30, Aurora B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups. In addition, therapeutic approaches for the treatment of TGCTs have been proposed: humanized antibodies against receptors/surface molecules on cancer cells, inhibitors of serine-threonine, and tyrosine kinases, and others. The mini-review will be an overview on the molecular alterations identified in TGCTs and on novel targeted antineoplastic strategies that might help to treat chemotherapy resistant TGCTs.

Differential translation of Dazap1 transcripts during spermatogenesis

Deleted in AZoospermia Associated Protein 1 (DAZAP1) is a ubiquitous hnRNP protein that has been implicated in RNA transcription, splicing, and translation. It is highly expressed in testes, predominantly in late stage spermatocytes and post-meiotic spermatids. Dazap1 deficiency in mice results in growth retardation and spermatogenic arrest. The gene produces two major transcripts of 2.4 and 1.8 kb, designated Dazap1-L and Dazap1-S, respectively. Results of our previous RNA in situ hybridization and immunostaining suggested translational regulation of the Dazap1 transcripts during spermatogenesis. The main objectives of the study were to determine the origin of the two Dazap1 transcripts and to investigate whether they were similarly translated. Our Northern and 3′ RACE analyses showed that the two transcripts were generated through alternative polyadenylation. In mouse testes, the levels of both transcripts were low at postnatal day 12 (P12), increased significantly at P18, and reached maximum at P27. Sucrose gradient analyses showed that at P12 both transcripts were actively translated. Afterward, an increasing portion of Dazap1-S became associated with the translationally inactive mRNPs, and the translational repression was accompanied by an increase in the length of its poly(A) tail. A much smaller portion of Dazap1-L was also sequestered to mRNPs as testes matured, but there was no changes in its poly(A) tail length. Using RNA pull-down followed by mass spectrometry, we identified DAZL, a germ-cell specific translation regulator, as one of the proteins that bound to the 3′UTR region specific for Dazap1-L. We further showed that DAZL preferentially bound to Dazap1-L in testis lysates and stimulated the translation of a reporter gene carrying Dazap1-L 3′UTR. In summary, our study shows that the translation of the two Dazap1 transcripts is differentially regulated. It also provides a new example of translational repression associated with poly(A) tail elongation during spermatogenesis.

Recent advances in the biology of germ cell tumors: implications for the diagnosis and treatment

Testicular germ cell tumors (TGCT), are the most frequent solid malignant tumors in men 20-40 yr of age, and the most frequent cause of death from solid tumors in this age group. TGCT can be subdivided into seminoma and nonseminoma germ cell tumors (NSGCT), including embryonal cell carcinoma, choriocarcinoma, yolk sac tumor, and teratoma. Seminomas and NSGCT do not only present distinctive clinical features, but they also show significant differences as far as therapy and prognosis are concerned. Many novel markers have given further advantages to discriminate between histological subgroups. In addition, therapeutic approaches for the treatment of TGCT have been proposed: humanized antibodies against receptors/surface molecules on cancer cells, inhibitors of serine-threonine, and tyrosine kinases, and others. The review will focus on the recent advances in the research of molecular alterations identified in TGCT and on novel targeted anti-neoplastic strategies that might help to treat chemotherapy-resistant TGCT.

Developmental expression of the pluripotency factor sal-like protein 4 in the monkey, human and mouse testis: restriction to premeiotic germ cells

SALL4 (sal-like protein 4) is a pluripotency transcription factor, which is highly expressed in embryonic stem (ES) cells and which is essential for mouse preimplantation development. In adult mouse organs, Sall4 mRNA is highly expressed in the testis and ovary, while there is only little or no expression in other organs. There is also a high expression of SALL4 in human testicular germ cell tumors. However, there is as yet no detailed analysis of SALL4 expression during mammalian testicular development. We analyzed SALL4 expression in ES cells, preimplantation embryos, and the developing and adult testis of a nonhuman primate (NHP) species, the common marmoset monkey (Callithrix jacchus). Immunofluorescence revealed SALL4 in the nuclei of marmoset ES cells and preimplantation embryos. Marmoset SALL4 isoform analysis in ES cells and newborn and adult testis by RT- PCR and Western blotting showed two different isoforms, SALL4-A and SALL4-B. Immunohistochemistry localized this transcription factor to the nuclei of primordial germ cells and most gonocytes in the prenatal and early postnatal marmoset testis. In the pubertal and adult testis SALL4 was present in undifferentiated spermatogonia. In the developing and adult human and mouse testis SALL4 expression mimicked the pattern in the marmoset. Adult testes from additional NHP species, the treeshrew, the cat and the dog also exhibited SALL4 in undifferentiated spermatogonia, indicating a conserved expression in the mammalian testis. Taking into account the importance of SALL4 for mouse development, we conclude that SALL4 may play an important role during mammalian germ cell development and is involved in the regulation of spermatogonial proliferation in the adult testis.

piRNA profiling during specific stages of mouse spermatogenesis

PIWI-interacting RNAs (piRNAs) are a class of small RNAs abundantly expressed in animal gonads. piRNAs that map to retrotransposons are generated by a "ping-pong" amplification loop to suppress the activity of retrotransposons. However, the biogenesis and function of other categories of piRNAs have yet to be investigated. In this study, we first profiled the expression of small RNAs in type A spermatogonia, pachytene spermatocytes, and round spermatids by deep sequencing. We then focused on the computational analysis of the potential piRNAs generated in the present study as well as other published sets. piRNAs mapping to retrotransposons, mRNAs, and intergenic regions had different length distributions and were differentially regulated in spermatogenesis. piRNA-generating mRNAs (PRMRs), whose expression positively correlated with their piRNA products, constituted one-third of the protein-coding genes and were evolutionarily conserved and enriched with splicing isoforms and antisense transcripts. PRMRs with piRNAs preferentially mapped to CDSs and 3' UTRs partitioned into three clusters differentially expressed during spermatogenesis and enriched with unique sets of functional annotation terms related to housekeeping activities as well as spermatogenesis-specific processes. Intergenic piRNAs were divided into 2992 clusters probably representing novel transcriptional units that have not been reported. The transcripts of a large number of genes involved in spermatogenesis are the precursors of piRNAs, and these genes are intricately regulated by alternative splicing and antisense transcripts. piRNAs, whose regulatory role in gene expression awaits to be identified, are clearly products of a novel regulatory process that needs to be defined.

Accessory olfactory bulb neurons are required for maintenance but not induction of V2R vomeronasal receptor gene expression in vitro

Many mammals detect pheromones by a sensory organ, the vomeronasal organ (VNO). In a previous study using immunoblot and immunocytochemical analyses, we reported that cocultures of VNOs with accessory olfactory bulb (AOB) neurons resulted in the maturation of vomeronasal sensory neurons (VSNs) and a greater expression of V2R family vomeronasal receptors than cultures with VNO alone. To further characterize the V2R expression, we here investigated the time course of the expression of V2R mRNA in the presence or absence of AOB neurons using RT-PCR analysis. The expression of V2R mRNA was already detectable not only in the VNO cocultured with AOB neurons for 3 days in coculture but also in the VNO cultured alone for the same number of days. However, the expression of V2R mRNA in the VNO cultured alone was remarkably decreased during the additional culture period, although that in the cocultured VNO showed sustained expression. Moreover, the application of 2 μM TTX to the cocultured VNO resulted in a marked decrease in the V2R mRNA expression to a level equal to that in the VNO cultured alone for 14 days in coculture. Our previous working hypothesis was that the expression of V2Rs in VSNs was induced by interacting with AOB neurons. However, the present results suggest that the receptor expression in VSNs is independent of the interaction with AOB neurons in the early developmental stage, but is maintained by the active interaction with AOB neurons.

Down-regulation of oestrogen receptor-β associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas

Oestrogen exposure has been linked to a risk for the development of testicular germ cell cancers. The effects of oestrogen are now known to be mediated by oestrogen receptor-α (ERα) and ERβ subtypes, but only ERβ has been found in human germ cells of normal testis. However, its expression was markedly diminished in seminomas, embryonal cell carcinomas and mixed germ cell tumours, but remains high in teratomas. PATZ1 is a recently discovered zinc finger protein that, due to the presence of the POZ domain, acts as a transcriptional repressor affecting the basal activity of different promoters. We have previously described that PATZ1 plays a crucial role in normal male gametogenesis and that its up-regulation and mislocalization could be associated with the development of testicular germ cell tumours. Here we show that ERβ interacts with PATZ1 in normal germ cells, while down-regulation of ERβ associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas. In addition, we show that the translocation of PATZ1 from the cytoplasm into the nucleus is regulated by cAMP, which also induces increased expression and nuclear localization of ERβ, while this effect is counteracted by using the anti-oestrogen ICI 182-780.

Identification of polymorphism and association analysis with reproductive traits in the porcine RNF4 gene

The ring finger protein 4 gene (RNF4), which might play a role in fetal germ cell development as well as in oocyte and granulosa cell maturation, was one of the potential candidate genes for reproductive traits. In the present work, we isolated the complete coding sequence of porcine RNF4 gene, identified a single nucleotide polymorphism (SNP: T/C) in intron5, and developed a PCR-SacII-RFLP genotyping assay. Association of this SNP with reproductive traits was assessed in three populations with diverse genetic backgrounds. One was Chinese Qingping sows. Another was consisted of crossbred sows derived from Landrace, Large White, Chinese Tongcheng and/or Chinese Meishan (Line DIV). The third is Large White x Meishan (LW x M) F(2) slaughtered population. Statistical analysis demonstrated that, in the first parity, the difference between RNF4 genotypes and reproductive traits of both Qingping and Line DIV sows was not significant. In the second and subsequent litters, CC animals in Qingping population had more piglets born (+1.74 piglets) and piglets born alive (+2.02 piglets) than sows with the TT genotype (P<0.05). Line DIV sows inheriting the CC genotype had additional 0.69 piglets born compared to the TC animals (P<0.05) in second and subsequent litters. No significant difference was observed between genotypes and reproductive tracts components in F(2) animals. In addition, we found RNF4 gene has a significant additive effect on both piglet born and piglet born alive in Qingping animals (P<0.05). Results here suggested that the RNF4 SNP was significantly associated with litter size in two populations and could be useful in selection for increasing litter size in pigs. Further studies were needed to confirm these preliminary researches.

Molecular basis of pregnancy-induced breast cancer protection

We have postulated that the lifetime protective effect of an early pregnancy against breast cancer is due to the complete differentiation of the mammary gland characterized by a specific genomic signature imprinted by the physiological process of pregnancy. In the present work, we show evidence that the breast tissue of postmenopausal parous women has had a shifting of stem cell 1 to stem cell 2 with a genomic signature different from similar structures derived from postmenopausal nulliparous women that have stem cell 1. Those genes that are significantly different are grouped in major categories on the basis of their putative functional significance. Among them are those gene transcripts related to immune surveillance, DNA repair, transcription, chromatin structure/activators/co-activators, growth factor and signal transduction pathway, transport and cell trafficking, cell proliferation, differentiation, cell adhesion, protein synthesis and cell metabolism. From these data, it was concluded that during pregnancy there are significant genomic changes that reflect profound alterations in the basic physiology of the mammary gland that explain the protective effect against carcinogenesis. The implication of this knowledge is that when the genomic signature of protection or refractoriness to carcinogenesis is acquired by the shifting of stem cell 1 to stem cell 2, the hormonal milieu induced by pregnancy or pregnancy-like conditions is no longer required. This is a novel concept that challenges the current knowledge that a chemopreventive agent needs to be given for a long period to suppress a metabolic pathway or abrogate the function of an organ.

Characterisation of the mulibrey nanism-associated TRIM37 gene: transcription initiation, promoter region and alternative splicing

The TRIM37 gene encodes a peroxisomal protein of unknown function. Mutations in TRIM37 underlie mulibrey nanism, a rare autosomal recessively inherited disorder with severe growth failure of prenatal onset, constrictive pericardium, hepatomegaly and characteristic dysmorphic features. Eleven mulibrey nanism-associated mutations have been identified. We here characterised TRIM37 further by mapping the transcription initiation site and promoter region as well as by analysing splice variants. By primer extension analysis, several transcription initiation sites were localised to a region between -246 and -373 relative to the ATG codon for translation initiation. Basal promoter activity was mapped within 600 nucleotides upstream from the translation initiation site using promoter-luciferase reporter constructs. Several alternative splice variants of TRIM37 exist in databases. Most of these predict non-functional protein products, are expressed at low levels and are thus likely to be targets for nonsense-mediated mRNA decay. A novel splice variant, TRIM37b, with an alternative termination codon and 3'untranslated region (UTR) transcribed from an exon 16 kb downstream from exon 24, predicts an identical protein product with the previously identified transcript, TRIM37a. As seen by Northern blot analysis and quantitative real-time PCR, both transcripts are highly expressed in testis, whereas in other tissues TRIM37a is prominent. The 3'UTR of the PPM1E gene in the opposite strand overlaps TRIM37b. These data suggest that TRIM37 expression is regulated by several mechanisms: through nonsense surveillance of non-functional transcripts, as well as through 3'UTR regulatory sequences and/or naturally occurring antisense RNAs especially in testis.

Patterns, mechanisms, and functions of translation regulation in mammalian spermatogenic cells

Translational regulation is a fundamental aspect of the atypical patterns of gene expression in mammalian meiotic and haploid spermatogenic cells. Every mRNA is at least partially translationally repressed in meiotic and haploid spermatogenic cells, but the extent of repression of individual mRNA species is regulated individually and varies greatly. Many mRNA species, such as protamine mRNAs, are stored in translationally repressed free-mRNPs in early haploid cells and translated actively in late haploid cells. However, translation does not regulate developmental expression of all mRNAs. Some mRNAs appear to be partially repressed for the entire period that the mRNA is expressed in meiotic and haploid cells, while other mRNAs, some of which are expressed at high levels, are almost totally inactivated in free-mRNPs and/or generate little or no protein. This distinctive phenomenon can be explained by the hypothesis that translational repression is used to prevent the potentionally deleterious effects of overproduction of proteins encoded by overexpressed mRNAs. Translational regulation also appears to be frequently altered by the widespread usage of alternative transcription start sites in spermatogenic cells. Many ubiquitously expressed genes generate novel transcripts in somatic spermatogenic cells containing elements, uORFs and secondary structure that are inhibitory to mRNA translation, while the ribosomal proten L32 mRNA lacks a repressive element that is present in somatic cells. Very little is known about the mechanisms that regulate mRNA translation in spermatogenic cells, largely because few labs have utilized in vivo genetic approaches, although there have been important insights into the repression and activation of protamine 1 mRNA, and the role of Y-box proteins and poly(A) lengthening in mRNA-specific translational activation mediated by the cytoplasmic poly(A) element binding protein and a testis-specific isoform of poly(A) polymerase. A very large literature by evolutionary biologists suggests that the atypical patterns of gene expression in spermatogenic cells are the consequence of the powerful and unusual selective pressures on male reproductive success.

Tumor necrosis factor-alpha inhibits peroxisome proliferator-activated receptor gamma activity at a posttranslational level in hepatic stellate cells

Diminished activity of peroxisome proliferator-activated receptor gamma (PPARgamma) is implicated in activation of hepatic stellate cells (HSC), a critical event in the development of liver fibrosis. In the present study, we investigated PPARgamma regulation by TNF-alpha in an HSC line designated as BSC. In BSC, TNF-alpha decreased both basal and ligand (GW1929)-induced PPARgamma mRNA levels without changing its protein expression. Nuclear extracts from BSC treated with TNF-alpha showed decreased binding of PPARgamma to PPAR-responsive element (PPRE) as determined by electrophoretic mobility shift assay. In BSC transiently transfected with a PPARgamma1 expression vector and a PPRE-luciferase reporter gene, TNF-alpha decreased both basal and GW1929-induced transactivation of the PPRE promoter. TNF-alpha increased activation of ERK1/2 and JNK, previously implicated in phosphorylation of Ser(82) of PPARgamma1 and resultant negative regulation of PPARgamma transactivity. In fact, TNF-alpha failed to inhibit transactivity of a Ser(82)Ala PPARgamma1 mutant in BSC. TNF-alpha-mediated inhibition of PPARgamma transactivity was not blocked with a Ser(32)Ala/Ser(36)Ala mutant of inhibitory NF-kappaBalpha (IkappaBalpha). These results suggest that TNF-alpha inhibits PPARgamma transactivity in cultured HSC, at least in part, by diminished PPARgamma-PPRE (DNA) binding and ERK1/2-mediated phosphorylation of Ser(82) of PPARgamma1, but not via the NF-kappaB pathway.