The GTPase SPAG-1 orchestrates meiotic program by dictating meiotic resumption and cytoskeleton architecture in mouse oocytes

Syphilis and the host: multi-omic analysis of host cellular responses to Treponema pallidum provides novel insight into syphilis pathogenesis

Introduction

Syphilis is a chronic, multi-stage infection caused by the extracellular bacterium Treponema pallidum ssp. pallidum. Treponema pallidum widely disseminates through the vasculature, crosses endothelial, blood-brain and placental barriers, and establishes systemic infection. Although the capacity of T. pallidum to traverse the endothelium is well-described, the response of endothelial cells to T. pallidum exposure, and the contribution of this response to treponemal traversal, is poorly understood.

Methods

To address this knowledge gap, we used quantitative proteomics and cytokine profiling to characterize endothelial responses to T. pallidum.

Results

Proteomic analyses detected altered host pathways controlling extracellular matrix organization, necroptosis and cell death, and innate immune signaling. Cytokine analyses of endothelial cells exposed to T. pallidum revealed increased secretion of interleukin (IL)-6, IL-8, and vascular endothelial growth factor (VEGF), and decreased secretion of monocyte chemoattractant protein-1 (MCP-1).

Discussion

This study provides insight into the molecular basis of syphilis disease symptoms and the enhanced susceptibility of individuals infected with syphilis to HIV co-infection. These investigations also enhance understanding of the host response to T. pallidum exposure and the pathogenic strategies used by T. pallidum to disseminate and persist within the host. Furthermore, our findings highlight the critical need for inclusion of appropriate controls when conducting T. pallidum-host cell interactions using in vitro- and in vivo-grown T. pallidum.

Inhibition of the NF-κB signaling pathway affects gonadal differentiation and leads to male bias in Paramisgurnus dabryanus

In recent years, sex-controlled breeding has emerged as an effective strategy to enhance the yields of economic animals with different growth characteristics, while increasing the economic benefits of aquaculture. It is known that the NF-κB pathway participates in gonadal differentiation and reproduction. Therefore, we used the large-scale loach as a research model for the present study and selected an effective inhibitor of the NF-κB signaling pathway (QNZ). This, to investigates the impacts of the NF-κB signaling pathway on gonadal differentiation during a critical period of gonad development and after maturation. Simultaneously, the sex ratio bias and the reproductive capacities of adult fish were analyzed. Our results indicated that the inhibition of the NF-κB signaling pathway influenced the expression of genes related to gonad development, regulated the gene expression related to the brain-gonad-liver axis of juvenile loaches, and finally impacted the gonadal differentiation of the large-scale loach and promoted a male-biased sex ratio. Meanwhile, high QNZ concentrations affected the reproductive abilities of adult loaches and inhibited the growth performance of offspring. Thus, our results deepened the exploration of sex control in fish and provided a certain research basis for the sustainable development of the aquaculture industry.

Bromoacetic acid impairs mouse oocyte in vitro maturation through affecting cytoskeleton architecture and epigenetic modification

As a major public health achievement, disinfection of drinking water significantly decreases outbreaks of waterborne disease, but produces drinking water disinfection by-products (DBPs) unfortunately. The haloacetic acids (HAAs) including bromoacetic acid (BAA), the second major class of DBPs, are considered as a global public health concern. BAA has been identified as cytotoxic, genotoxic, mutagenic, carcinogenic, and teratogenic in somatic cells. However, the toxic effects of BAA on oocyte maturation remain obscure. Herein, we documented that exposure to BAA compromised mouse oocyte maturation in vitro, causing blocked polar body extrusion (PBE). Meiotic progression analysis demonstrated that exposure to BAA induced the activated spindle assembly checkpoint (SAC) mediated metaphase I (MI) arrest in oocytes. Further study revealed that exposure to BAA resulted in the hyperacetylation of α-tubulin, disrupting spindle assembly and chromosome alignment, which is responsible for the activation of SAC. Besides, the organization of actin, the other major component of cytoskeleton in oocytes, was disturbed after BAA exposure. In addition, exposure to BAA altered the status of histone H3 methylation and 5 mC, indicative of the damaged epigenetic modifications. Moreover, we found that exposure to BAA induced DNA damage in a dose-dependent manner in oocytes. Collectively, our study evidenced that exposure to BAA intervened mouse oocyte maturation via disrupting cytoskeletal dynamics, damaging epigenetic modifications and inducing accumulation of DNA damage.

Perfluorooctanoic acid alters the developmental trajectory of female germ cells and embryos in rodents and its potential mechanism

The epidemiological studies regarding perfluorooctanoic acid (PFOA) suggests that its exposure causes reproductive health issues, the underlying mechanisms of which are still in its infancy. Here, we report that PFOA deteriorates female reproduction at multiple development stages. Oocyte meiosis and preimplantation development are severely impaired by PFOA with oxidative stress being a contributor. Supplementing with antioxidant melatonin partially rescues oocyte meiotic maturation and non-apoptotic demise. The attenuation in ovarian follicle development however can be improved by metformin but not melatonin. Importantly, metformin blunts PFOA-induced fetal growth retardation (FGR) and such protective effect could be recapitulated by transplantation of fecal material and pharmacological activation of AMPK. Mechanistically, PFOA causes gut microbiota dysbiosis, which might thereby rewire host metabolism of L-phenylalanine, histamine and L-palmitoylcarnitine that triggers hyperphenylalaninaemia, inflammation and ferroptosis to initiate FGR. Deregulated serine metabolism by the gut microbe constitutes an alternative mechanism underlying PFOA-induced FGR in that modulation of serine in dam's diet phenocopied the FGR. Our study expands the understanding of risk factors that impair human reproductive health, and proposes restoration of gut microbiota diversity and intervention of metabolism as therapeutics mitigating health risks predisposed by environmental perturbation.

Zinc pyrithione exposure compromises oocyte maturation through involving in spindle assembly and zinc accumulation

Zinc Pyrithione (ZPT), a Food and Drug Administration (FDA) approved chemical, is widely used for topical antimicrobials and cosmetic consumer products, including anti-dandruff shampoos. ZPT and its degraded byproducts have detected in large quantities in the environment, and identified to pose healthy risks on aquatic organisms and human. However, so far, knowledge about ZPT effects on female reproduction, particularly oocyte maturation and quality, is limited. Herein, we investigated the adverse impact of ZPT on mouse oocyte maturation and quality in vitro and found exposure to ZPT significantly compromises oocyte maturation. The results revealed that ZPT disturbed the meiotic cell cycle by impairing cytoskeletal dynamics, kinetochore-microtubule attachment (K-MT), and causing spindle assembly checkpoints (SAC) continuous activation. Further, we observed the microtubule-organizing centers (MTOCs) associated proteins p-MAPK and Aurora-A were disrupted in ZPT-treated oocytes, signified by decreased expression and abnormal localization, responsible for the severe cytoskeletal defects. In addition, ZPT exposure induced a significant increase in the levels of H3K9me2, H3K9me3, H3K27me1, and H3K27me3, suggesting the alterations of epigenetic modifications. Moreover, the accumulation of zinc ions (Zn2+) was observed in ZPT-treated oocytes, which was detrimental because overmuch intracellular Zn2+ disrupted oocyte meiosis. Finally, these above alterations impaired spindle organization and chromosome alignment in metaphase-II (MII) oocytes, indicative of damaged oocytes quality. In conclusion, ZPT exposure influenced oocyte maturation and quality via involvement in MTOCs-associated proteins mediated spindle defects, altered epigenetic modifications and zinc accumulation.

The role of SPAG1 in the assembly of axonemal dyneins in human airway epithelia

Mutations in SPAG1, a dynein axonemal assembly factor (DNAAF) that facilitates the assembly of dynein arms in the cytoplasm before their transport into the cilium, result in primary ciliary dyskinesia (PCD), a genetically heterogenous disorder characterized by chronic oto-sino-pulmonary disease, infertility and laterality defects. To further elucidate the role of SPAG1 in dynein assembly, we examined its expression, interactions and ciliary defects in control and PCD human airway epithelia. Immunoprecipitations showed that SPAG1 interacts with multiple DNAAFs, dynein chains and canonical components of the R2TP complex. Protein levels of dynein heavy chains (DHCs) and interactions between DHCs and dynein intermediate chains (DICs) were reduced in SPAG1 mutants. We also identified a previously uncharacterized 60 kDa SPAG1 isoform, through examination of PCD subjects with an atypical ultrastructural defect for SPAG1 variants, that can partially compensate for the absence of full-length SPAG1 to assemble a reduced number of outer dynein arms. In summary, our data show that SPAG1 is necessary for axonemal dynein arm assembly by scaffolding R2TP-like complexes composed of several DNAAFs that facilitate the folding and/or binding of the DHCs to the DIC complex.

Sperm Associated Antigens: Vigorous Influencers in Life

Sperm associated antigens (SPAGs) are specific proteins in terms of performance and evolution, that have common expressions in the testes or sperm cells. Moreover, the humoral immune response against some of SPAGs can result in immunological infertilities. On the other hand, recent studies have explored several new properties of SPAGs and shed light on sperm's function, the impact of anti-sperm antibodies (ASA) in immunological infertility, and some tumors related to SPAGs. This article presents an exhaustive review of SPAGs and their roles in the cell cycle, signaling pathways, fertility, sperm-oocyte cross-talk as well as their unfavorable positions as prognostic factors in many types of cancers.

Perfluorononanoic acid impedes mouse oocyte maturation by inducing mitochondrial dysfunction and oxidative stress

Perfluorononanoic acid (PFNA), a member of PFAS, is frequently detected in human blood and tissues, even in follicular fluid of women. The exposure of PFNA, but not PFOA and PFOS, is positively correlated with miscarriage and increased time to pregnancy. Toxicological studies indicated that PFNA exposure is associated with immunotoxicity, hepatotoxicity, developmental toxicity, and reproductive toxicity in animals. However, there is little information regarding the toxic effects of PFNA on oocyte maturation. In this study, we investigated the toxic effects of PFNA exposure on mouse oocyte maturation in vitro. Our results showed that 600 μM PFNA significantly inhibited germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) in mouse oocytes. Our further study revealed that PFNA induced abnormal metaphase I (MI) spindle assembly, evidenced by malformed spindles and mislocalization of p-ERK1/2 in PFNA-treated oocytes. We also found that PFNA induced abnormal mitochondrial distribution and increased mitochondrial membrane potential. Consequently, PFNA increased reactive oxygen species (ROS) levels, leading to oxidative stress, DNA damage, and eventually early-stage apoptosis in oocytes. In addition, after 14 h culture, PFNA disrupted the formation of metaphase II (MII) spindle in most PFNA-treated oocytes with polar bodies. Collectively, our results indicate that PFNA interferes with oocyte maturation in vitro via disrupting spindle assembly, damaging mitochondrial functions, and inducing oxidative stress, DNA damage, and early-stage apoptosis.

Gene Expression Alteration of Sperm-Associated Antigens in Human Cryopreserved Sperm

Background: Sperm-associated antigens (SPAGs) are 18 types of proteins, some of which play important roles in various biological functions associated with assisted reproductive technology outcomes, and are consequently important to the success of fertility programs. Despite the favorable outcomes of fecundity rates among male patients with cancer using cryopreserved sperm, the detrimental impact of freezing on cells has been noted in many studies. Cryopreservation has been thought to have adverse effects on sperm quality through disruptions in the expressions of SPAG genes. This study aimed to evaluate the effects of cryopreservation on the expressions of SPAGs genes and their transcriptome alterations in human sperm. Materials and Methods: A total of 12 normal ejaculations were prepared using the density gradient centrifugation procedure, and the motile sperm fractions were divided into fresh and frozen groups. In the latter, sperm samples were mixed with SpermFreeze^® solution as the cryoprotectant. The cryovial of sperm suspension was first held just over nitrogen vapor and then dipped inside liquid nitrogen. After 3 days, the specimens were thawed in tap water and incubated for 2 hours for recovery. Then, RNA from sperm was extracted for SPAG gene expression analysis, using real-time polymerase chain reaction. Results: Our findings showed a decrease in expression of SPAG5 (p-value = 0.009), SPAG7 (p-value = 0.004), and SPAG12 (SNU13/NHP2L1; p-value = 0.039) genes during cryopreservation. Discussion: The results indicate that the freezing procedure could negatively affect gene expression and to some extent proteins in human spermatozoa. Conclusion: The alteration of SPAG expression could provide new information on the molecular correlation between cryopreservation and increased failure in intracytoplasmic sperm injection and in vitro fertilization.

Expression and Prognosis of Sperm-Associated Antigen 1 in Human Breast Cancer

Background

Sperm-associated antigen 1 (SPAG1) has been identified as a marker of pancreatic cancer progression and promoter of cell motility; however, its role in breast cancer is not completely understood.

Methods

SPAG1 expression in breast cancer tissues and normal tissues was obtained from online databases. Knockdown function assays were designed and conducted to verify the functional role of SPAG1 in breast cancer cell lines. Cell counting and MTT assays were used to assess cell proliferation. Cell flow cytometry assay was used for cell cycle phase arrest, and fluorescence microscopy was used for colony formation assessment.

Results

Both the mRNA and protein levels of SPAG1 were significantly higher in the breast cancer tissues than in the normal tissues. In addition, SPAG1 is significantly related to many clinicopathological features of breast cancer, such as age (>51 years), estrogen receptor (ER) (+), progesterone receptor (PR) (+), and nodal status (+), non-triple negative breast cancer (TNBC), not basal-like and not basal-like and not TNBC. Survival analysis indicates that breast cancer patients with low expression of SPAG1 had a significantly better prognosis with relapse-free survival (RFS). Functional experiment analysis revealed that knockdown of SPAG1 suppressed cell proliferation and colony-forming ability.

Conclusion

Our results suggested a possible role of SPAG1 in breast cancer pathogenesis.

Triclocarban exposure affects mouse oocyte in vitro maturation through inducing mitochondrial dysfunction and oxidative stress

Triclocarban (TCC), a broad-spectrum lipophilic antibacterial agent, is the main ingredient of personal and health care products. Nonetheless, its ubiquitous presence in the environment has been established to negatively affect the reproduction in humans and animals. In this work, we studied the possible toxic effects of TCC on mouse oocytes maturation in vitro. Our findings revealed that TCC-treated immature mouse oocytes had a significantly reduced rate of polar body extrusion (PBE) compared to that of control. Further study demonstrated that the cell cycle progression and cytoskeletal dynamics were disrupted after TCC exposure, which resulted in the continuous activation of spindle assembly checkpoint (SAC). Moreover, TCC-treated oocytes had mitochondrial damage, reduced ATP content, and decreased mitochondrial membrane potential (MMP). Furthermore, TCC exposure induced oxidative stress and subsequently triggered early apoptosis in mouse oocytes. Besides, the levels of histone methylation were also affected, as indicated by increased H3K27me2 and H3K27me3 levels. In summary, our results revealed that TCC exposure disrupted mouse oocytes maturation through affecting cell cycle progression, cytoskeletal dynamics, oxidative stress, early apoptosis, mitochondria function, and histone modifications in vitro.

Binding properties of the quaternary assembly protein SPAG1

In cells, many constituents are able to assemble resulting in large macromolecular machineries possessing very specific biological and physiological functions, e.g. ribosome, spliceosome and proteasome. Assembly of such entities is commonly mediated by transient protein factors. SPAG1 is a multidomain protein, known to participate in the assembly of both the inner and outer dynein arms. These arms are required for the function of sensitive and motile cells. Together with RUVBL1, RUVBL2 and PIH1D2, SPAG1 is a key element of R2SP, a protein complex assisting the quaternary assembly of specific protein clients in a tissue-specific manner and associating with heat shock proteins (HSPs) and regulators. In this study, we have investigated the role of TPR domains of SPAG1 in the recruitment of HSP chaperones by combining biochemical assays, ITC, NMR spectroscopy and molecular dynamics (MD) simulations. First, we propose that only two, out of the three TPR domains, are able to recruit the protein chaperones HSP70 and HSP90. We then focused on one of these TPR domains and elucidated its 3D structure using NMR spectroscopy. Relying on an NMR-driven docking approach and MD simulations, we deciphered its binding interface with the C-terminal tails of both HSP70 and HSP90. Finally, we addressed the biological function of SPAG1 and specifically demonstrated that a SPAG1 sub-fragment, containing a putative P-loop motif, cannot efficiently bind and hydrolyze GTP in vitro Our data challenge the interpretation of SPAG1 possessing GTPase activity. We propose instead that SPAG1 regulates nucleotide hydrolysis activity of the HSP and RUVBL1/2 partners.

Hypoxia Causes Transgenerational Impairment of Ovarian Development and Hatching Success in Fish

Hypoxia is a pressing environmental problem in both marine and freshwater ecosystems globally, and this problem will be further exacerbated by global warming in the coming decades. Recently, we reported that hypoxia can cause transgenerational impairment of sperm quality and quantity in fish (in F0, F1, and F2 generations) through DNA methylome modifications. Here, we provide evidence that female fish ( Oryzias melastigma) exposed to hypoxia exhibit reproductive impairments (follicle atresia and retarded oocyte development), leading to a drastic reduction in hatching success in the F2 generation of the transgenerational group, although they have never been exposed to hypoxia. Further analyses show that the observed transgenerational impairments in ovarian functions are related to changes in the DNA methylation and expression pattern of two gene clusters that are closely associated with stress-induced cell cycle arrest and cell apoptosis. The observed epigenetic and transgenerational alterations suggest that hypoxia may pose a significant threat to the sustainability of natural fish populations.

SEC-induced activation of ANXA7 GTPase suppresses prostate cancer metastasis

Annexin A7 (ANXA7) is a suppressor of tumorigenesis and metastasis in prostate cancer. Activated ANXA7 GTPase promotes prostate cancer cell apoptosis. However, the role and underlying mechanism of ANXA7 GTPase in prostate cancer metastasis have not been established. RKIP is a metastatic suppressor and downregulated in prostate cancer metastases. The binding of RKIP and its target proteins could inhibit the activation of its interactive partners. However, the effect of RKIP on ANXA7 GTPase activation is not clear. Here, we report that activation of ANXA7 GTPase by a small molecule SEC ((S)-ethyl 1-(3-(4-chlorophenoxy)-2-hydroxypropyl)-3- (4-methoxyphenyl)-1H-pyrazole-5-carboxylate) effectively inhibited prostate cancer metastasis. Mechanistically, activated ANXA7 promoted AMPK phosphorylation, leading to decreased mTORC1 activity, suppressed STAT3 nuclear translocation, and downregulation of pro-metastatic genes, including CCL2, APLN, and IL6ST. Conversely, RKIP interacted with ANXA7 and impaired activation of ANXA7 GTPase by SEC and its downstream signaling pathway. Notably, SEC treatment suppressed metastasis of prostate cancer cells in in vivo orthotopic analysis. Together, our findings provide a novel insight into how metastasis of prostate cancer with low RKIP expression is suppressed by SEC-induced activation of ANXA7 GTPase via the AMPK/mTORC1/STAT3 signaling pathway.

miR-638 Inhibits immature Sertoli cell growth by indirectly inactivating PI3K/AKT pathway via SPAG1 gene

Numerous studies have demonstrated that microRNAs (miRNAs) play important roles in cell growth, apoptosis and spermatogenesis. Our previous study showed that miR-638 was differentially expressed in sexually immature and mature testes of Large White boars. Here we reported that sperm-associated antigen 1 (SPAG1) was a direct target gene of miR-638. Moreover, miR-638 inhibited cell proliferation and cell cycle, and promoted apoptosis of porcine immature Sertoli cells. Key genes including phosphorylated phosphatidylinositide 3-kinases (p-PI3K) and phosphorylated serine/ threonine kinase (p-AKT) in PI3K/AKT pathway as well as cell cycle factors including c-MYC, cyclin-D1 (CCND1), cyclin-E1 (CCNE1) and cyclin-dependent kinase 4 (CDK4) were all significantly down-regulated after overexpression of miR-638 or RNAi of SPAG1. Notably, mRNA levels of SRY-related HMG-box 2 (SOX2) and POU domain, class 5, transcription factor 1 (POU5F1) essential for spermatogonia proliferation were significantly suppressed in SPAG1 siRNA- transfected ST cells. This study suggests that miR-638 regulates immature Sertoli cell growth and apoptosis by targeting SPAG1 gene which can indirectly inactivate PI3K/AKT pathway, and plays roles in pig spermatogenesis.

Maternal SENP7 programs meiosis architecture and embryo survival in mouse

Understanding the mechanisms underlying abnormal egg production and pregnancy loss is significant for human fertility. SENP7, a SUMO poly-chain editing enzyme, has been regarded as a mitotic regulator of heterochromatin integrity and DNA repair. Herein, we report the roles of SENP7 in mammalian reproductive scenario. Mouse oocytes deficient in SENP7 experienced meiotic arrest at prophase I and metaphase I stages, causing a substantial decrease of mature eggs. Hyperaceylation and hypomethylation of histone H3 and up-regulation of Cdc14B/C accompanied by down-regulation of CyclinB1 and CyclinB2 were further recognized as contributors to defective M-phase entry and spindle assembly in oocytes. The spindle assembly checkpoint activated by defective spindle morphogenesis, which was also caused by mislocalization and ubiquitylation-mediated proteasomal degradation of γ-tubulin, blocked oocytes at meiosis I stage. SENP7-depleted embryos exhibited severely defective maternal-zygotic transition and progressive degeneration, resulting in nearly no blastocyst production. The disrupted epigenetic landscape on histone H3 restricted Rad51C loading onto DNA lesions due to elevated HP1α euchromatic deposition, and reduced DNA 5hmC challenged the permissive status for zygotic DNA repair, which induce embryo death. Our study pinpoints SENP7 as a novel determinant in epigenetic programming and major pathways that govern oocyte and embryo development programs in mammals.

The cohesion stabilizer sororin favors DNA repair and chromosome segregation during mouse oocyte meiosis

Maintenance and timely termination of cohesion on chromosomes ensures accurate chromosome segregation to guard against aneuploidy in mammalian oocytes and subsequent chromosomally abnormal pregnancies. Sororin, a cohesion stabilizer whose relevance in antagonizing the anti-cohesive property of Wings-apart like protein (Wapl), has been characterized in mitosis; however, the role of Sororin remains unclear during mammalian oocyte meiosis. Here, we show that Sororin is required for DNA damage repair and cohesion maintenance on chromosomes, and consequently, for mouse oocyte meiotic program. Sororin is constantly expressed throughout meiosis and accumulates on chromatins at germinal vesicle (GV) stage/G2 phase. It localizes onto centromeres from germinal vesicle breakdown (GVBD) to metaphase II stage. Inactivation of Sororin compromises the GVBD and first polar body extrusion (PBE). Furthermore, Sororin inactivation induces DNA damage indicated by positive γH2AX foci in GV oocytes and precocious chromatin segregation in MII oocytes. Finally, our data indicate that PlK1 and MPF dissociate Sororin from chromosome arms without affecting its centromeric localization. Our results define Sororin as a determinant during mouse oocyte meiotic maturation by favoring DNA damage repair and chromosome separation, and thereby, maintaining the genome stability and generating haploid gametes.