Nuclear factor-κB (NF-κB) regulates the expression of human testis-enriched Leucine-rich repeats and WD repeat domain containing 1 (LRWD1) gene

MicroRNA-320a enhances LRWD1 expression through the AGO2/FXR1-dependent pathway to affect cell behaviors and the oxidative stress response in human testicular embryonic carcinoma cells

BACKGROUND

Testicular cancer is fairly rare but can affect fertility in adult males. Leucine-rich repeats- and WD repeat domain-containing protein 1 (LRWD1) is a sperm-specific marker that mainly affects sperm motility in reproduction. Our previous study demonstrated the impact of LRWD1 on testicular cancer development; however, the underlying mechanisms remain unclear.

METHODS

In this study, various plasmids associated with LRWD1 and miR-320a manipulation were used to explore the roles and regulatory effects of these molecules in NT2D1 cellular processes. A Dual-Glo luciferin-luciferase system was used to investigate LRWD1 transcriptional activity, and qRT-PCR and western blotting were used to determine gene and protein expression.

RESULTS

The results suggested that miR-320a positively regulated LRWD1 and positively correlated with NT2D1 cell proliferation but negatively correlated with cell migration and invasion ability. In addition, the miRNA-ribonucleoprotein complex AGO2/FXR1 was shown to be essential in the mechanism by which miR-320a regulates LRWD1 mRNA expression. As miR-320a was required to regulate LRWD1 expression through the AGO2 and FXR1 complex, eEF2 and eLF4E were also found to be involved in miR-320a increasing LRWD1 expression. Furthermore, miR-320a and LRWD1 were responsive to oxidative stress, and NRF2 was affected by the presence of miR-320a in response to ROS stimulation.

CONCLUSIONS

This is the first study showing the role of miR-320a in upregulating the testicular cancer-specific regulator LRWD1 and the importance of the AGO2/FXR1 complex in miR-320a-mediated upregulation of LRWD1 during testicular cancer progression.

Metformin alleviates the dysregulated testicular steroidogenesis and spermatogenesis induced by carbimazole in levothyroxine-primed rats

Most of the published experiments about carbimazole (CMZ)-induced testicular injury are constructed in normal healthy animals, which lakes the translational identification. Despite metformin (MET) having advantageous effects on injured testicles, its impact on thyroid function is arguable. In the current levothyroxine (LT4)/CMZ model, Wistar rats were primed by LT4 for sixty days. CMZ was then given individually or simultaneously with different doses of MET, 100, 200, and 400 mg, daily for thirty days. Serum was assessed for thyroid profile panel, sex hormones, and gonadotropin levels. Testicular tissues were examined for steroidogenesis, spermatogenesis, inflammation, and apoptosis. Histopathology of thyroid and testes were examined, besides thyroidal nuclear factor (NF)-kB expression. MET in a dose-response manner improved the LT4/CMZ-induced testicular toxicity by increasing the steroidogenic acute regulatory protein (StAR), and 17-β-hydroxysteroid dehydrogenase (17βHSD) activities, the proliferating cell nuclear antigen (PCNA), sperm count and motility, sex hormones, and gonadotropin levels. MET-400 mg markedly decreased the elevated NF-kB expressions, tumour necrosis factor (TNF)-α, caspase-3, and BAX, and increased BCL-2. LT4/CMZ could be used as translational animal modelling. MET displayed a dose-dependent ameliorative effect on the LT4/CMZ model without significant harmful effects on thyroid functions. MET-testicular protective roles in diabetics with thyroidal diseases should be explored.

Comparative proteomics analysis of human FFPE testicular tissues reveals new candidate biomarkers for distinction among azoospermia types and subtypes

Understanding molecular mechanisms that underpin azoospermia and discovery of biomarkers that could enable reliable, non-invasive diagnosis is highly needed. Using label-free data-independent LC-MS/MS acquisition coupled with ion mobility, we compared the FFPE testicular proteome of patients with obstructive (OA) and non-obstructive azoospermia (NOA) subtypes hypospermatogenesis (Hyp) and Sertoli cell-only syndrome (SCO). Out of 2044 proteins identified based on ≥2 peptides, 61 proteins had the power to quantitatively discriminate OA from NOA and 30 to quantitatively discriminate SCO from Hyp and OA. Among these, H1-6, RANBP1 and TKTL2 showed superior potential for quantitative discrimination among OA, Hyp and SCO. Integrin signaling pathway, adherens junction, planar cell polarity/convergent extension pathway and Dectin-1 mediated noncanonical NF-kB signaling were significantly associated with the proteins that could discriminate OA from NOA. Comparison with 2 transcriptome datasets revealed 278 and 55 co-differentially expressed proteins/genes with statistically significant positive correlation. Gene expression analysis by qPCR of 6 genes (H1-6, RANBP1, TKTL2, TKTL1, H2BC1, and ACTL7B) with the highest discriminatory power on protein level and the same regulation trend with transcriptomic datasets, confirmed proteomics results. In summary, our results suggest some underlying pathways in azoospermia and broaden the range of potential novel candidates for diagnosis. SIGNIFICANCE: Using a comparative proteomics approach on testicular tissue we have identified several pathways associated with azoospermia and a number of testis-specific and germ cell-specific proteins that have the potential to pinpoint the type of spermatogenesis failure. Furthermore, comparison with transcriptomics datasets based on genome-wide gene expression analyses of human testis specimens from azoospermia patients identified proteins that could discriminate between obstructive and non-obstructive azoospermia subtypes on both protein and mRNA levels. Up to our knowledge, this is the first integrated comparative analysis of proteomics and transcriptomics data from testicular tissues. We believe that the data from our study contributes significantly to increase the knowledge of molecular mechanisms of azoospermia and pave the way for new investigations in regards to non-invasive diagnosis.

Lrwd1 impacts cell proliferation and the silencing of repetitive DNA elements

LRWD1, also known as ORCA, is a nuclear protein functioning in multiple biological processes. Using its WD40 domain LRWD1 interacts with repressive histone marks and maintains the silencing of heterochromatin regions in mammalian cells. ORCA also associates with the origin recognition complex (ORC) and facilitates prereplication complex formation at late‐replicating origins. However, whether LRWD1 plays a role during development and the functional significance of LRWD1 in vivo remains largely unknown. Using gene‐trap approach we generated Lrwd1 knockout mice and examined the expression of Lrwd1 during embryonic development. We found that Lrwd1 is ubiquitously expressed in the majority of the developing mouse embryo. Depletion of LRWD1 did not affect embryonic development but the postnatal growth of the homozygous mutants is retarded. In vitro cultured mouse embryonic fibroblasts (MEFs) depleted of LRWD1 displayed a reduced proliferation compared to wild type cells. We also showed that the knockout of Lrwd1 in MEFs increased the expression of the epigenetically silenced repetitive elements but with minimal effect on the expression of protein coding genes. Together, these results suggest that LRWD1 plays an important, but not essential, role in postnatal development by regulating cell proliferation likely through modulating DNA replication.

microRNAs in the pathogenesis of non-obstructive azoospermia: the underlying mechanisms and therapeutic potentials

miRNAs are involved in different biological processes, including proliferation, differentiation, and apoptosis. Interestingly, 38% of the X chromosome-linked miRNAs are testis-specific and have crucial roles in regulating the renewal and cell cycle of spermatogonial stem cells. Previous studies demonstrated that abnormal expression of spermatogenesis-related miRNAs could lead to nonobstructive azoospermia (NOA). Moreover, differential miRNAs expression in seminal plasma of NOA patients has been reported compared to normozoospermic men. However, the role of miRNAs in NOA pathogenesis and the underlying mechanisms have not been comprehensively studied. Therefore, the aim of this review is to mechanistically describe the role of miRNAs in the pathogenesis of NOA and discuss the possibility of using the miRNAs as therapeutic targets.Abbreviations: AMO: anti-miRNA antisense oligonucleotide; AZF: azoospermia factor region; CDK: cyclin-dependent kinase; DAZ: deleted in azoospermia; ESCs: embryonic stem cells; FSH: follicle-stimulating hormone; ICSI: intracytoplasmic sperm injection; JAK/STAT: Janus kinase/signal transducers and activators of transcription; miRNA: micro-RNA; MLH1: Human mutL homolog l; NF-κB: Nuclear factor-kappa B; NOA: nonobstructive azoospermia; OA: obstructive azoospermia; PGCs: primordial germ cells; PI3K/AKT: Phosphatidylinositol 3-kinase/protein kinase B; Rb: retinoblastoma tumor suppressor; ROS: Reactive Oxygen Species; SCOS: Sertoli cell-only syndrome; SIRT: sirtuin; SNPs: single nucleotide polymorphisms; SSCs: spermatogonial stem cells; TESE: testicular sperm extraction; TGF-β: transforming growth factor-beta.

LRWD1 expression is regulated through DNA methylation in human testicular embryonal carcinoma cells

BACKGROUND

Sperm growth and maturation are correlated with the expression levels of Leucine-rich repeat and WD repeat-containing protein 1 (LRWD1), a widely expressed protein in the human testicles. The decrease in LRWD1 cellular level was linked to the reduction in cell growth and mitosis and the rise in cell microtubule atrophy rates. Since DNA methylation has a major regulatory role in gene expression, this study aimed at exploring the effect of the modulation of DNA methylation on LRWD1 expression levels.

RESULTS

The results revealed the presence of a CpG island up of 298 bps (- 253 ~ + 45) upon LRWD1 promoter in NT2/D1 cells. The hypermethylation of the LRWD1 promoter was linked to a reduction in the transcription activity in NT2/D1 cells, as indicated by luciferase reporter assay. The methylation activator, floxuridine, confirmed the decrease in the LRWD1 promoter transcriptional activity. On the other hand, 5-Aza-2'-deoxycytidine (5-Aza-dc, methylation inhibitor), significantly augmented LRWD1 promoter activity and the expression levels of mRNA and proteins. Furthermore, DNA methylation status of LRWD1 promoter in human sperm genomic DNA samples was analyzed. The results indicated that methylation of LRWD1 promoter was correlated to sperm activity.

CONCLUSIONS

Thus, the regulation of LRWD1 expression is correlated with the methylation status of LRWD1 promoter, which played a significant role in the modulation of spermatogenesis, sperm motility, and vitality. Based on these results, the methylation status of LRWD1 promoter may serve as a novel molecular diagnostic marker or a therapeutic target in males' infertility.

PRSS50 is a testis protease responsible for proper sperm tail formation and function

Multiple morphological abnormalities of the sperm flagella (MMAF) are a major cause of asthenoteratozoospermia. We have identified protease serine 50 (PRSS50) as having a crucial role in sperm development, because Prss50-null mice presented with impaired fertility and sperm tail abnormalities. PRSS50 could also be involved in centrosome function because these mice showed a threefold increase in acephalic sperm (head-tail junction defect), sperm with multiple heads (spermatid division defect) and sperm with multiple tails, including novel two conjoined sperm (complete or partial parts of several flagellum on the same plasma membrane). Our data support that, in the testis, as in tumorigenesis, PRSS50 activates NFκB target genes, such as the centromere protein leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1), which is required for heterochromatin maintenance. Prss50-null testes have increased IκκB, and reduced LRWD1 and histone expression. Low levels of de-repressed histone markers, such as H3K9me3, in the Prss50-null mouse testis may cause increases in post-meiosis proteins, such as AKAP4, affecting sperm formation. We provide important insights into the complex mechanisms of sperm development, the importance of testis proteases in fertility and a novel mechanism for MMAF.

Identification of SEPTIN12 as a novel target of the androgen and estrogen receptors in human testicular cells

SEPTIN12 (SEPT12) is a testis-enriched gene that is downregulated in the testis of infertile men with severe spermatogenic defects. While SEPT12 is involved in spermatogenic failure and sperm motility disorder, SEPT12 transcriptional regulation is still unknown. Here we report the promoter region of SEPT12 as a 245 bp segment upstream of the transcription start site. One androgen receptor (AR) and two estrogen receptor α (ERα) binding sites in this region were initially identified by bioinformatics prediction and confirmed by chromatin immunoprecipitation assay. Truncated ERα or AR binding sites decreased the promoter activity, which indicated that the ERα and AR are essential for the SEPT12 promoter. On the other hand, the promoter activity was enhanced by the treatment with 17β-estradiol (E2) and 5α-dihydrotestosterone (5α-DHT). Thus, one androgen and two estrogen hormone responsive elements located in the promoter of SEPT12 gene can regulate SEPT12 expression. Two single nucleotide polymorphisms (SNPs), rs759992 T > C and rs3827527 C > T, were observed in the SEPT12 gene promoter region and were able to decrease the promoter activity. In conclusion, the current work identified the promoter of the human SEPT12 gene and provided key evidence about its transcriptional regulation via E2 and 5α-DHT. Since SEPT12 has an important role in spermatogenesis, SEPT12 expression analysis can be developed as a potential tool for the assessment of environmental or food pollution by hormones or for the evaluation of the risk of endocrine-disrupting chemicals (EDCs) in general.

Nuclear factor erythroid-2-related factor regulates LRWD1 expression and cellular adaptation to oxidative stress in human embryonal carcinoma cells

Leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1) is implicated in the regulation of signal transduction, transcription, RNA processing and tumor development. However, LRWD1 transcriptional regulation is not fully understood. This study aimed to investigate the relationship between LRWD1 expression and reactive oxygen species (ROS) level in human embryonal carcinoma cell line, NT2/D1 cells, which will help in understanding the transcriptional regulatory role of ROS in cells. Results showed that the exposure of NT2/D1 cells to various concentrations of hydrogen peroxide (H₂O₂) and the nitric oxide (NO) donor sodium nitroprusside (SNP) caused a significant increase in the mRNA and protein expression of LRWD1. In addition, LRWD1 promoter luciferase reporter assay, and Chromatin Immunoprecipitation assay (CHIP assay) showed that nuclear factor erythroid-2-related factor (Nrf2) was involved in the regulation of LRWD1 expression in response to oxidative stress. The involvement of Nrf2 was confirmed by shRNA-mediated knockdown of Nrf2 in NT2/D1 cells, which caused a significant decrease in LRWD1 expression in response to oxidative stress. Similarly, LRWD1 knockdown resulted in the accumulation of H₂O₂ and superoxide anion radical (O2-). Blocking ROS production by N-acetyl cysteine (NAC) protected NT2/D1 shLRWD1cells from H₂O₂-induced cell death. Collectively, oxidative stress increased LRWD1 expression through a Nrf2-dependent mechanism, which plays an important role in cellular adaptation to oxidative stress. These results highlight an evidence, on the molecular level, about LRWD1 transcriptional regulation under oxidative stress.

Association of MTHFR, NFKB1, NFKBIA, DAZL and CYP1A1 gene polymorphisms with risk of idiopathic male infertility in a Han Chinese population

In this study, we investigated the association between six genetic polymorphisms (MTHFR C677T and A1298C, NFKB1 -94ins/del ATTG, NFKBIA 3'UTR A>G, DAZL A386G (T54A) and CYP1A1 T3801C) and the risk of idiopathic male infertility in a Chinese population. A case-control study comprising 1,759 idiopathic male infertile patients of Han Chinese ethnicity and 1,826 healthy fertile control individuals was carried out. Genotypes of all polymorphisms were determined via PCR-RFLP. Chi-squared test and logistic regression modeling were performed to identify the association of the polymorphisms with idiopathic male infertility. It was found that the heterozygous and variant genotypes of the following polymorphisms were significantly associated with an increased idiopathic male infertility risk: MTHFR C677T (heterozygous OR=1.266 [1.089, 1.470], P=0.002; variant OR=1.384 [1.138, 1.684], P=0.001), MTHFR A1298C (heterozygous OR=1.233 [1.071, 1.419], P=0.004; variant OR=1.564 [1.183, 2.068], P=0.002), and CYP1A1 T3801C (heterozygous OR=1.163 [1.007, 1.344], P=0.040; variant OR=1.232 [1.005, 1.510], P=0.045). When genotypes of non-significant polymorphisms were combined and analyzed, it was found that the combination between variant DD genotype of NFKB1 -94ins/del ATTG polymorphism and heterozygous AG genotype of DAZL A386G polymorphism was significantly associated with a reduced idiopathic male infertility risk (OR=0.588 [0.376, 0.919], P=0.02). In summary, we have successfully identified the association (or lack thereof) between the polymorphisms and idiopathic male infertility risk.

High-throughput RNAi screen in Ewing sarcoma cells identifies leucine rich repeats and WD repeat domain containing 1 (LRWD1) as a regulator of EWS-FLI1 driven cell viability

A translocation leading to the formation of an oncogenic EWS-ETS fusion protein defines Ewing sarcoma. The most frequent gene fusion, present in 85 percent of Ewing sarcomas, is EWS-FLI1. Here, a high-throughput RNA interference screen was performed to identify genes whose function is critical for EWS-FLI1 driven cell viability. In total, 6781 genes were targeted by siRNA molecules and the screen was performed both in presence and absence of doxycycline-inducible expression of the EWS-FLI1 shRNA in A673/TR/shEF Ewing sarcoma cells. The Leucine rich repeats and WD repeat Domain containing 1 (LRWD1) targeting siRNA pool was the strongest hit reducing cell viability only in EWS-FLI1 expressing Ewing sarcoma cells. LRWD1 had been previously described as a testis specific gene with only limited information on its function. Analysis of LRWD1 mRNA levels in patient samples indicated that high expression associated with poor overall survival in Ewing sarcoma. Gene ontology analysis of LRWD1 co-expressed genes in Ewing tumors revealed association with DNA replication and analysis of differentially expressed genes in LRWD1 depleted Ewing sarcoma cells indicated a role in connective tissue development and cellular morphogenesis. Moreover, EWS-FLI1 repressed genes with repressive H3K27me3 chromatin marks were highly enriched among LRWD1 target genes in A673/TR/shEF Ewing sarcoma cells, suggesting that LRWD1 contributes to EWS-FLI1 driven transcriptional regulation. Taken together, we have identified LRWD1 as a novel regulator of EWS-FLI1 driven cell viability in A673/TR/shEF Ewing sarcoma cells, shown association between high LRWD1 mRNA expression and aggressive disease and identified processes by which LRWD1 may promote oncogenesis in Ewing sarcoma.

Functional activity of the porcine Gnrhr2 gene promoter in testis-derived cells is partially conferred by nuclear factor-κB, specificity protein 1 and 3 (SP1/3) and overlapping early growth response 1/SP1/3 binding sites

Unlike the classical gonadotropin-releasing hormone (GnRH1), the second mammalian isoform (GnRH2) is ubiquitously expressed, suggesting a divergent function. Indeed, we demonstrated that GnRH2 governs LH-independent testosterone secretion in porcine testes via interaction with its receptor (GnRHR2) on Leydig cells. Transient transfections with luciferase reporter vectors containing 3009bp of 5' flanking sequence for the porcine Gnrhr2 gene (-3009pGL3) revealed promoter activity in all 15 cell lines examined, including swine testis-derived (ST) cells. Therefore, ST cells were utilized to explore the molecular mechanisms underlying transcriptional regulation of the porcine Gnrhr2 gene in the testis. Reporter plasmids containing progressive 5' deletions of the Gnrhr2 promoter indicated that the -708/-490 region contained elements critical to promoter activity. Electrophoretic mobility shift assays (EMSAs) with radiolabeled oligonucleotides spanning the -708/-490bp region and ST nuclear extracts, identified specific binding complexes for the -513/-490, -591/-571 and -606/-581bp segments of promoter. Antibody addition to EMSAs indicated that the p65 and p52 subunits of nuclear factor-κB (NF-κB) comprised the specific complex bound to the oligonucleotide probe for the -513/-490bp promoter region, specificity protein (SP) 1 and 3 bound the -591/-571bp probe and early growth response 1 (EGR1), SP1 and SP3 bound the -606/-581 radiolabeled oligonucleotide. Transient transfections with vectors containing mutations of the NF-κB (-499/-493), SP1/3 (-582/-575) or overlapping EGR1/SP1/3 (-597/-587) binding sites reduced luciferase activity by 26%, 61% and 56%, respectively (P<0.05). Thus, NF-κB, SP1/3 and overlapping EGR1/SP1/3 binding sites are critical to expression of the porcine Gnrhr2 gene in ST cells.

Correlation between leucine rich domain and the stability of LRWD1 protein in human NT2/D1 cells

PURPOSE

LRWD1 is a protein that contains LRR and WDs domains and is important in regulating spermatogenesis. However, the roles of LRR or WDs domains in the expression of LRWD1 remain unclear.

MATERIALS AND METHODS

The NT2/D1 cells separately transfected with full length of LRWD1 gene (LRWD(WT)) or genes with deleted sequences in the LRR domain (LRWD1(ΔLRR)), WD1 domain (LRWD1(ΔWD1)), WD2 domain (LRWD1(ΔWD2)), WD3 domain (LRWD1(ΔWD3)) and entire three WD domains (LRWD1(Δ3×WD)) were applied to investigate the expression levels of LRWD1 protein by either Western blot or flow cytometry. The associated proteins in these mutated LRWD1 proteins were identified by mass spectrometry.

RESULTS

Deletion of the LRR domain significantly decreased the expression of LRWD1 protein. With the treatment of MG132, the LRR domain may functions in preventing LRWD1 protein from proteasome-mediated degradation. In the co-immunoprecipitation analysis, protein receptor of tumor necrosis factor 2 (TNFR2) was specifically observed to be associated with LRR-deficient LRWD1 protein.

CONCLUSIONS

The LRR domain is significantly correlated to the stability of LRWD1 protein. Determining if the stability is modulated by TNFR2 is worthy of further study.

Enhanced expression of WD repeat-containing protein 35 via nuclear factor-kappa B activation in bupivacaine-treated Neuro2a cells

The family of WD repeat proteins comprises a large number of proteins and is involved in a wide variety of cellular processes such as signal transduction, cell growth, proliferation, and apoptosis. Bupivacaine is a sodium channel blocker administered for local infiltration, nerve block, epidural, and intrathecal anesthesia. Recently, we reported that bupivacaine induces reactive oxygen species (ROS) generation and p38 mitogen-activated protein kinase (MAPK) activation, resulting in an increase in the expression of WD repeat-containing protein 35 (WDR35) in mouse neuroblastoma Neuro2a cells. It has been shown that ROS activate MAPK through phosphorylation, followed by activation of nuclear factor-kappa B (NF-κB) and activator protein 1 (AP-1). The present study was undertaken to test whether NF-κB and c-Jun/AP-1 are involved in bupivacaine-induced WDR35 expression in Neuro2a cells. Bupivacaine activated both NF-κB and c-Jun in Neuro2a cells. APDC, an NF-κB inhibitor, attenuated the increase in NF-κB activity and WDR35 protein expression in bupivacaine-treated Neuro2a cells. GW9662, a selective peroxisome proliferator-activated receptor-γ antagonist, enhanced the increase in NF-κB activity and WDR35 protein expression in bupivacaine-treated Neuro2a cells. In contrast, c-Jun siRNA did not inhibit the bupivacaine-induced increase in WDR35 mRNA expression. These results indicate that bupivacaine induces the activation of transcription factors NF-κB and c-Jun/AP-1 in Neuro2a cells, while activation of NF-κB is involved in bupivacaine-induced increases in WDR35 expression.

The origin recognition complex in human diseases

ORC (origin recognition complex) serves as the initiator for the assembly of the pre-RC (pre-replication complex) and the subsequent DNA replication. Together with many of its non-replication functions, ORC is a pivotal regulator of various cellular processes. Notably, a number of reports connect ORC to numerous human diseases, including MGS (Meier-Gorlin syndrome), EBV (Epstein-Barr virus)-infected diseases, American trypanosomiasis and African trypanosomiasis. However, much of the underlying molecular mechanism remains unclear. In those genetic diseases, mutations in ORC alter its function and lead to the dysregulated phenotypes; whereas in some pathogen-induced symptoms, host ORC and archaeal-like ORC are exploited by these organisms to maintain their own genomes. In this review, I provide detailed examples of ORC-related human diseases, and summarize the current findings on how ORC is involved and/or dysregulated. I further discuss how these discoveries can be generalized as model systems, which can then be applied to elucidating other related diseases and revealing potential targets for developing effective therapies.