Hao Chen

Bio: Hao Chen is an academic researcher from Guangdong University of Technology. The author has contributed to research in topics: Materials science & Cancer. The author has an hindex of 2, co-authored 3 publications receiving 38 citations. Previous affiliations of Hao Chen include Nantong University.

Impairment of spermatogenesis and sperm motility by the high-fat diet-induced dysbiosis of gut microbes

Abstract: Objective High-fat diet (HFD)-induced metabolic disorders can lead to impaired sperm production. We aim to investigate if HFD-induced gut microbiota dysbiosis can functionally influence spermatogenesis and sperm motility. Design Faecal microbes derived from the HFD-fed or normal diet (ND)-fed male mice were transplanted to the mice maintained on ND. The gut microbes, sperm count and motility were analysed. Human faecal/semen/blood samples were collected to assess microbiota, sperm quality and endotoxin. Results Transplantation of the HFD gut microbes into the ND-maintained (HFD-FMT) mice resulted in a significant decrease in spermatogenesis and sperm motility, whereas similar transplantation with the microbes from the ND-fed mice failed to do so. Analysis of the microbiota showed a profound increase in genus Bacteroides and Prevotella, both of which likely contributed to the metabolic endotoxaemia in the HFD-FMT mice. Interestingly, the gut microbes from clinical subjects revealed a strong negative correlation between the abundance of Bacteroides-Prevotella and sperm motility, and a positive correlation between blood endotoxin and Bacteroides abundance. Transplantation with HFD microbes also led to intestinal infiltration of T cells and macrophages as well as a significant increase of pro-inflammatory cytokines in the epididymis, suggesting that epididymal inflammation have likely contributed to the impairment of sperm motility. RNA-sequencing revealed significant reduction in the expression of those genes involved in gamete meiosis and testicular mitochondrial functions in the HFD-FMT mice. Conclusion We revealed an intimate linkage between HFD-induced microbiota dysbiosis and defect in spermatogenesis with elevated endotoxin, dysregulation of testicular gene expression and localised epididymal inflammation as the potential causes. Trial registration number NCT03634644.

Influence of convection on the upper-tropospheric O₃ and NO_<i>x</i> budget in southeastern China

Abstract: Abstract. Thunderstorms can significantly influence the air composition via strong updraft and lightning nitrogen oxides (LNOx). In this study, the ozonesondes and TROPOMI (TROPOspheric Monitoring Instrument) nitrogen dioxide (NO2) observations for two cases are combined with a model to investigate the effects of typical strong convection on vertical redistribution of air pollutants in Nanjing, southeastern China. The ozonesonde observations show higher O3 and water vapor mixing ratios in the upper troposphere (UT) after convection, indicating the strong updraft transporting lower-level air masses into the UT and the possible downward O3-rich air near the top of UT over the convective period. During the whole convection life cycle, the UT O3 production is driven by the chemistry (5–10 times the magnitude of dynamic contribution) and reduced by the LNOx (−40 %). Sensitivity tests demonstrate that neglecting LNOx in standard TROPOMI NO2 products causes overestimated air mass factors over fresh lightning regions and the opposite for outflow and aged lightning areas. Therefore, a new high-resolution retrieval algorithm is applied to estimate the LNOx production efficiency. Our work shows the demand for high-resolution modeling and satellite observations on LNOx emissions of both active and dissipated convection, especially small-scale storms.

Cellular apoptosis susceptibility protein (CAS) suppresses the proliferation of breast cancer cells by upregulated cyp24a1.

Abstract: Breast cancer is the most common cancer in women. Although several studies demonstrated cellular apoptosis susceptibility protein (CAS) involved in the development of breast cancer, the underlying mechanisms of CAS regulating cell processes in the breast cancer remain elusive. In the present study, we explored the possible mechanism of CAS in contributing to the cell proliferation in the breast cancer cell line MCF-7. Knockdown of CAS led to the reduction of cell viability and proliferation. Furthermore, cell cycle was arrested in G0/G1 phase after knocking down CAS with the decrease of cyclinD1. In addition, RNA-seq analysis for the CAS knockdown cells demonstrated that total eleven genes were significantly altered (Fold changes > 2). Of note, the expression of cyp24a1 was dramatically increased in the shCAS cells compared to that of shNC cells as well as confirmed by quantitative real-time polymerase chain reaction (qPCR). These observations clarified the previous conflicting results on the cell fates of the breast cells regulated by CAS and provide new insight into the role of CAS in the development of breast cancer.

Diet and Nutritional Factors in Male (In)fertility-Underestimated Factors.

Abstract: In up to 50% of cases, infertility issues stem solely from the male. According to some data, the quality of human semen has deteriorated by 50%–60% over the last 40 years. A high-fat diet and obesity, resulting from an unhealthy lifestyle, affects the structure of spermatozoa, but also the development of offspring and their health in later stages of life. In obese individuals, disorders on the hypothalamic-pituitary-gonadal axis are observed, as well as elevated oestrogen levels with a simultaneous decrease in testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels. Healthy dietary models clearly correlate with better sperm quality and a smaller risk of abnormalities in parameters such as sperm count, sperm concentration and motility, and lower sperm DNA fragmentation. Apart from mineral components such as zinc and selenium, the role of omega-3 fatty acids and antioxidant vitamins should be emphasized, since their action will be primarily based on the minimization of oxidative stress and the inflammation process. Additionally, the incorporation of carnitine supplements and coenzyme Q10 in therapeutic interventions also seems promising. Therefore, it is advisable to have a varied and balanced diet based on vegetables and fruit, fish and seafood, nuts, seeds, whole-grain products, poultry, and low-fat dairy products.

Improvement in sperm quality and spermatogenesis following faecal microbiota transplantation from alginate oligosaccharide dosed mice.

Abstract: Very recent publications in Gut and elsewhere1 2 suggest that gut microbiota affects fertility. The application of faecal microbiota transplantation (FMT) to modify fertility is an emerging novel area of interest.3 FMT from women with polycystic ovary syndrome (PCOS) leads to the disruption of ovarian function and a decrease in fertility which indicates that modification of gut microbiota may be a valuable approach in the management of PCOS.2 FMT of gut microbes, that developed under a high-fat diet, into mice on a normal diet leads to the disruption of spermatogenesis and a reduction of sperm motility,1 which highlights that restoring gut microbiota may be a means of improving disturbed male infertility caused by environmental factors.1 However, to date, there are no reports that address improvements of fertility following FMT. In a recent study,4 we found that busulfan damages spermatogenesis and sperm quality, and disturbs gut microbiota as found in many other studies.5 6 Alginate oligosaccharides (AOS), a natural product with many benefits, rescues busulfan disrupted spermatogenesis by supporting gut microbiota through an increase in ‘beneficial’ bacteria4 such as Bacteroidales and Lactobacillaceae and a decrease in ‘harmful’ bacteria, such as Desulfovibrionaceae .7 Gut microbiota from AOS dosed animals may improve spermatogenesis through benefit to the recipients gut microbes. To test this hypothesis, we set out to explore the beneficial improvement of sperm quality and …

Disrupted spermatogenesis in a metabolic syndrome model: the role of vitamin A metabolism in the gut-testis axis.

Abstract: Objective Effects of the diet-induced gut microbiota dysbiosis reach far beyond the gut. We aim to uncover the direct evidence involving the gut–testis axis in the aetiology of impaired spermatogenesis. Design An excessive-energy diet-induced metabolic syndrome (MetS) sheep model was established. The testicular samples, host metabolomes and gut microbiome were analysed. Faecal microbiota transplantation (FMT) confirmed the linkage between gut microbiota and spermatogenesis. Results We demonstrated that the number of arrested spermatogonia was markedly elevated by using 10× single-cell RNA-seq in the MetS model. Furthermore, through using metabolomics profiling and 16S rDNA-seq, we discovered that the absorption of vitamin A in the gut was abolished due to a notable reduction of bile acid levels, which was significantly associated with reduced abundance of Ruminococcaceae_NK4A214_group. Notably, the abnormal metabolic effects of vitamin A were transferable to the testicular cells through the circulating blood, which contributed to abnormal spermatogenesis, as confirmed by FMT. Conclusion These findings define a starting point for linking the testicular function and regulation of gut microbiota via host metabolomes and will be of potential value for the treatment of male infertility in MetS.

Microbiota from alginate oligosaccharide-dosed mice successfully mitigated small intestinal mucositis

Abstract: The increasing incidence of cancer and intestinal mucositis induced by chemotherapeutics are causing worldwide concern. Many approaches such as fecal microbiota transplantation (FMT) have been used to minimize mucositis. However, it is still unknown whether FMT from a donor with beneficial gut microbiota results in more effective intestinal function in the recipient. Recently, we found that alginate oligosaccharides (AOS) benefit murine gut microbiota through increasing “beneficial” microbes to rescue busulfan induced mucositis. In the current investigation, FMT from AOS-dosed mice improved small intestine function over FMT from control mice through the recovery of gene expression and an increase in the levels of cell junction proteins. FMT from AOS-dosed mice showed superior benefits over FMT from control mice on recipient gut microbiotas through an increase in “beneficial” microbes such as Leuconostocaceae and recovery in blood metabolome. Furthermore, the correlation of gut microbiota and blood metabolites suggested that the “beneficial” microbe Lactobacillales helped with the recovery of blood metabolites, while the “harmful” microbe Mycoplasmatales did not. The data confirm our hypothesis that FMT from a donor with superior microbes leads to a more profound recovery of small intestinal function. We propose that gut microbiota from naturally produced AOS-treated donor may be used to prevent small intestinal mucositis induced by chemotherapeutics or other factors in recipients.