Bolan Yu

Cigarette smoking is associated with abnormal histone-to-protamine transition in human sperm

OBJECTIVE To investigate the association between smoking, semen quality, and the histone-to-protamine transition ratio in mature sperm. DESIGN Biochemical and molecular analysis in human samples and a cell line. SETTING Andrology laboratory in a university-affiliated hospital. PATIENT(S) Semen samples from 147 heavy smokers and 175 nonsmokers receiving infertility treatment. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Basic semen parameters, histone-to-protamine ratios, and number of sperm cells with abnormal histone transition were calculated. The relative messenger RNA (mRNA) expression levels of protamine 1 and protamine 2 were assayed in human sperm and in TM3 cells exposed to cigarette smoke condensate. T tests, Spearman tests, and nonparametric Mann-Whitney U tests were used to detect significant differences. RESULT(S) Normozoospermic smokers had significantly higher abnormalities than their nonsmoking counterparts. Sperm histone replacement abnormalities were found to be closely correlated with sperm motility, viability, concentration, counts, and cotinine levels. The ratios of protamine 1 to protamine 2 mRNA expression significantly increased in heavy smokers and in TM3 cells treated with cigarette smoke condensate. CONCLUSION(S) Smoking is strongly associated with abnormalities in histone-to-protamine transition and with alteration of protamine mRNA expression in human sperm.

Cigarette Smoking Is Associated with Human Semen Quality in Synergy with Functional NRF2 Polymorphisms

ABSTRACT Although cigarette smoking is considered a major risk factor for several human diseases, the effects of smoking on male fertility are controversial. Studies on the consequences of smoking, which also take into account genetic background, may facilitate understanding of the interactions between genes and smoking and their effects on male fertility. In this study, genetic variants of two functional polymorphisms of erythroid 2-related factor 2 (NRF2), mRNA expression levels of the antioxidant gene NRF2, catalase (CAT), superoxide dismutase isoenzyme-2 (SOD2), glutathione S-transferase-M1 (GSTM1), and seminal SOD activities were compared in 314 heavy smokers and 314 matched nonsmokers. The NRF2 rs6721961 TT genotype was found to be associated with low semen quality in heavy smokers (OR [95% CI] = 2.370 [1.106–5.081]). This variant genotype was found more frequently in heavy smokers with low semen quality than in those with high semen quality (P = 0.011). Heavy smokers with this genotype had significantly lower sperm concentrations and sperm counts (P < 0.05) when compared with those without this genotype. Smoking was also significantly associated with decreased seminal SOD activity (P < 0.05) and reduced NRF2 and SOD2 mRNA expression in heavy smokers with this variant genotype. These results were specific to heavy smokers with the NRF2 rs6721961 TT genotypes, but did not apply to nonsmokers or heavy smokers that did not carry this genotype. This study suggests an association between cigarette smoking in heavy smokers with NRF2 rs6721961 TT genotype and a decrease in semen quality.

Functional polymorphisms of interferon-gamma affect pneumonia-induced sepsis.

Objective Sepsis is an inflammatory syndrome caused by infection, and both its incidence and mortality are high. Because interferon-gamma (IFN-γ) plays an important role in inflammation, this work assessed IFN-γ single nucleotide polymorphism (SNPs) that may be associated with sepsis. Methods A total of 196 patients with pneumonia-induced sepsis and 213 age- and sex-matched healthy volunteers participated in our study from July 2012 to July 2013 in Guangzhou, China. Patient clinical information was collected. Clinical pathology was assessed in subgroups defined based on clinical criteria, APACHE II (acute physiology and chronic health evaluation) and SOFA (sepsis-related organ failure assessment) scores and discharge rate. Four functional SNPs, −1616T/C (rs2069705), −764G/C (rs2069707), +874A/T (rs2430561) and +3234C/T (rs2069718), were genotyped by Snapshot in both sepsis patients and healthy controls. Pearson’s chi-square test or Fisher’s exact test were used to analyze the distribution of the SNPs, and the probability values (P values), odds ratios (OR) and 95% confidence intervals (CIs) were calculated. Results No mutations in the IFN-γ −764G/C SNP were detected among the participants in our study. The +874A/T and +3234C/T SNPs were in strong linkage disequilibrium (LD) (r2 = 0.894). The −1616 TC+TT, +874 AT+AA genotype and the TAC haplotype were significantly associated with sepsis susceptibility, while the CTT haplotype was associated with protection against sepsis incidence. Genotype of −1616 TT wasn’t only protective against severity of sepsis, but also against higher APACHE II and SOFA scores as +874 AA and +3234 CC. The TAC haplotype was was protective against progression to severe sepsis either. Conclusion Our results suggest that functional IFN-γ SNPs and their haplotypes are associated with pneumonia-induced sepsis.

The effects of cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression in mice.

Cigarette smoking can harm fertility, but the existing research has targeted primarily on ovarian follicles, embryos or sex hormone. In this study, we tested cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression associated with inhibition of oxidative stress using C57BL/6 mice. Mice in the experimental group were administered a cigarette smoke extract (CSE) solution (2 mg/ml) orally daily, while the blank control group was given dimethylsulfoxide (DMSO). A positive control group (menadione) was used that received an intraperitoneal injection of 15 mg/kg menadione in oil solution daily. We found that the CSE group manifested a reduced diameter of zona pellucida-free oocyte (ZP-free OD) and a morphologically misshapen first polar body (PB). Our results suggest that CSE exposure is associated with a shrink size and poor quality of oocytes. Quitting smoking is a wise choice to ensure good fertility.

Modeling induced pluripotent stem cells from fibroblasts of Duchenne muscular dystrophy patients

The generation of disease-specific induced pluripotent stem cell (iPS cell) lines from patients with incurable diseases is a promising approach for studying disease mechanisms and for drug screening. Such innovation enables us to obtain autologous cell sources for regenerative medicine. Herein, we report the generation and characterization of iPS cells from the fibroblasts of patients with a family history of Duchenne muscular dystrophy (DMD); these fibroblasts were obtained from patients at 22 gestational weeks of age and exhibit exon duplication from exons 16 to 42. The DMD-iPS cells were generated by the ectopic expression of four transcription factors: OCT4, SOX2, KLF4, and c-MYC; the DMD-iPS cells expressed several pluripotency markers and could be differentiated into various somatic cell types both in vitro and in vivo. Furthermore, DMD-iPSCs showed the differentiation potential to neuronal lineage. Thus, DMD-iPS cells are expected to serve as an in vitro disease model system, which will lay a foundation for the production of autologous cell therapies that avoid immune rejection and enable the correction of gene defects prior to tissue reconstitution.

Polycystic ovary syndrome resembling histopathological alterations in ovaries from prenatal androgenized female rats

BackgroundThe polycystic ovary syndrome ( PCOS) affects approximately 6-10% of women of reproductive age and is characterized by chronic anovulation and hyperandrogenism. However, a comprehensive understanding of the mechanisms that dictate androgen overproduction is lacking, which may account for inconsistencies between measures of androgen excess and clinical presentation in individual cases.MethodsA rat model of PCOS was established by injecting dehydroepiandrosterone sulfoconjugate (DHEAS) into pregnant females. Rats were administered with DHEAS (60 mg/kg/d) subcutaneously (s.c.) for all 20 days of pregnancy (Group A), or for the first 10 days (Group B), or from day 11 to day 20 (Group C). Controls were administered with injection oil (0.2 ml/day) s.c. throughout pregnancy (Group D). The litter rate, abortion rate, and offspring survival rate in each group were recorded. Serum androgen and estrogen were measured and the morphological features of the ovaries were examined by light and electron microscopy in the offspring of each group.ResultsWe found that rats injected with DHEAS throughout pregnancy (group A) lost fertility. Rats injected with DHEAS during early pregnancy (group B) exhibited more serious aberrations in fertility than both Group C, in which rats were injected with DHEAS during late pregnancy (P < 0.05), and Group D (controls). There was a statistical difference of ovarian weight among female offspring in Group B, C and D (P < 0.01). By light and electron microscopy, a significant morphological difference among the female offspring in the three groups was observed.ConclusionsOur results indicate that androgen excess during pregnancy can decrease rat fertility. Excess androgen at the early stage of pregnancy causes high reproductive toxicity, leading to abnormality of ovarian morphology and functions in female offspring.

Nuclear Factor Erythroid 2-related Factor 2 Deficiency Exacerbates Lupus Nephritis in B6/ lpr mice by Regulating Th17 Cell Function

Lupus nephritis (LN) is the major clinical manifestation of systemic lupus erythematosus. LN is promoted by T helper 17 (Th17) cells, which are the major pro-inflammatory T cell subset contributing to autoimmunity regulation. Nuclear factor erythroid 2-related factor 2 (NRF2) is critical for suppressing reactive oxygen species (ROS) and relieving oxidant stress by regulating antioxidant gene expression. Previous studies have demonstrated that Nrf2 deficiency promotes drug-induced or spontaneous LN. However, whether NRF2 regulates Th17 function during LN development is still unclear. In this study, we introduced Nrf2 deficiency into a well-known LN model, the B6/lpr mouse strain, and found that it promoted early-stage LN with altered Th17 activation. Th17 cells and their relevant cytokines were dramatically increased in these double-mutant mice. We also demonstrated that naïve T cells from the double-mutant mice showed significantly increased differentiation into Th17 cells in vitro, with decreased expression of the Th17 differentiation suppressor Socs3 and increased phosphorylation of STAT3. Our results demonstrated that Nrf2 deficiency promoted Th17 differentiation and function during LN development. Moreover, our results suggested that the regulation of Th17 differentiation via NRF2 could be a therapeutic target for the treatment of subclinical LN patients.

Uniparental disomy of the entire X chromosome in Turner syndrome patient-specific induced pluripotent stem cells.

The human induced pluripotent stem cell (iPSC) technique promises to provide an unlimited, reliable source of genetically matched pluripotent cells for personalized therapy and disease modeling. Recently, it is observed that cells with ring chromosomes 13 or 17 autonomously correct the defects via compensatory uniparental disomy during cellular reprogramming to iPSCs. This breakthrough finding suggests a potential therapeutic approach to repair large-scale chromosomal aberrations. However, due to the scarceness of ring chromosome samples, the reproducibility of this approach in different individuals is not carefully evaluated yet. Moreover, the underlying mechanism and the applicability to other types of chromosomal aberrations remain unknown. Here we generated iPSCs from four 45,X chorionic villous fibroblast lines and found that only one reprogrammed line acquired 46,XX karyotype via uniparental disomy of the entire X chromosome. The karyotype correction was reproducible in the same cell line by either retroviral or episomal reprogramming. The karyotype-corrected iPSCs were subject to X chromosome inactivation and obtained better colony morphology and higher proliferation rate than other uncorrected ones. Further transcriptomic comparison among the fibroblast lines identified a distinct expression pattern of cell cycle regulators in the uncorrectable ones. These findings demonstrate that the iPSC technique holds the potential to correct X monosomy, but the correction rate is very low, probably due to differential regulation of cell cycle genes between individuals. Our data strongly suggest that more systematic investigations are needed before defining the iPSC technique as a novel means of chromosome therapy.

Association of semen cytokines with reactive oxygen species and histone transition abnormalities

PurposeThe aim of this study is to investigate the relationships among reactive oxygen species (ROS) elevation, histone transition, and seminal cytokine concentrations.MethodsTotal levels of ROS in semen samples from 6560 men were measured. From this sample, 118 cases with high ROS and 106 controls were recruited. Basic semen parameters and histone-to-protamine ratios were analyzed, 400 semen cytokine and receptor alterations were assayed by protein chip, and finally 18 cytokines were validated in each sample using a Bio-Plex Cytokine assay.ResultsThe results showed that the seminal ROS concentration was associated with abnormalities in the sperm histone transition. Compared with controls, 93 cytokines had significant alterations in the high ROS cases, with 14 of them further verified in individual samples. The concentrations of CXCL5, CXCL16, CXCL8, IL-1b, IL-10, CSF3, CCL3, and TNF-α were significantly correlated with the histone transition ratio. In addition, IL-16 showed significantly different concentrations in controls, normal semen with high ROS levels, and abnormal semen with high ROS levels.ConclusionsSemen ROS are associated with abnormalities in sperm histone transition. CXCL5, CXCL8, IL-16, CCL8, CCL22, CCL20, CXCL16, IL-1B, IL-6, IL-7, IL-10, CSF3, CCL3, CCL4, and TNF-α all have elevated concentrations in semen with high ROS levels. These data might help to explain the mechanisms behind the increase in the levels of ROS and seminal cytokines and their relationship with defective spermatogenesis.

Smoking attenuated the association between IκBα rs696 polymorphism and defective spermatogenesis in humans

Defective spermatogenesis is prevalent in infertile men, but the molecular mechanisms underlying its aetiology are largely unknown. In this study, a proposed association between IκBα SNPs, smoking‐related ROS and sperm quality was investigated. Two polymorphisms in the IκBα gene, rs2233406 and rs696 were genotyped in 342 controls and 338 patients with defective spermatogenesis from a southern Chinese population. The results showed the rs696 AA genotype to be significantly more common (21.60% versus 14.33%, P = 0.013) and the rs696 GG genotype to be significantly rarer (28.99% versus 37.13%, P = 0.024) in the cases than in the controls. After subjects were stratified into smokers and nonsmokers, these differences were only observed in nonsmokers. Further analysis showed the rs696 AA genotype to be significantly closely associated with defective spermatogenesis in all subjects (P = 0.014, OR = 1.647) and in nonsmokers (P = 0.036, OR = 1.889). In a TM3 cell model, exposure to cigarette smoke condensate was found to activate NF‐κB luciferase activity and altered transcriptional level of NF‐κB pathway genes. In conclusion, this study demonstrates an association between functional polymorphisms of the IκBα rs696 and cigarette smoking with the risk of defective spermatogenesis, suggesting some interaction between the NF‐κB signalling pathway and smoking‐related ROS in human spermatogenesis.