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

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.

Influences of scutellarin on ATP-induced inflammasome activation and pyroptosis in J774A.1 macrophages / 中国药理学通报

Aim To explore the influences of scutellarin on ATP-induced NLRP3 inflammasome activation and pyroptosis,using LPS-primed murine macrophages J774A.1 as an inflammatory cell model,and to explore the underlying mechanism.Methods The effects of scutellarin on ATP-induced pyroptosis in murine J774A.1 macrophages were analyzed by propidium iodide (PI) staining assay.The levels of IL-1β,caspase-1 and HMGB1 in cell lysates and culture supernatants were analysed using Western blot.The levels of IL-1β in cell culture supernatants were measured by cytometric beads array (CBA).Results ATP significantly induced caspase-1 activation and mature IL-1β and HMGB1 release into the culture supernatants in LPS-primed murine J774A.1 macrophages,and induced pyroptosis.Scutellarin treatment dose-dependently inhibited ATP-induced caspase-1 activation,mature IL-1β and HMGB1 release,and pyroptosis.Notably,scutellarin's inhibitory effects on ATP-induced pyroptosis were markedly reversed by the adenylate cyclase inhibitor MDL12330A and selective protein kinase A (PKA) inhibitor H89.Conclusion Scutellarin inhibits NLRP3 inflammasome activation and pyroptosis by modulating the PKA activity in macrophages,thereby exhibiting anti-inflammatory activities.

Nitrogen-doped graphene quantum dots-labeled epitope imprinted polymer with double templates via the metal chelation for specific recognition of cytochrome c.

A novel fluorescent sensor nitrogen-doped graphene quantum dots (N-GQDs)/SiO2/molecular imprinting polymer（N-GQDs/SiO2/MIP）was fabricated by surface imprinting and epitope imprinting to recognize and detect the target protein cytochrome c (Cyt C) with fluorescence quenching. In the polymerization process, the C- and N-terminal nonapeptides of Cyt C were selected as the double templates which were fixed by functional monomer (zinc acrylate) through metal chelation and steady six-membered ring. The linear range of fluorescence quenching for this receptor towards Cyt C was 0.20-60µM, and the detection limit was 0.11µM. The precision for six times replicate determination of Cyt C at 30µM was 1.20%, and the imprinting factor (IF) was 3.06. The recoveries of the material to Cyt C in urine were 99.3-114.0%. In brief, this work proposed a strategy to prepare a new type fluorescent imprinting polymer based on N-GQDs and provided an attractive perspective for the detection of protein by using the combination of N-GQDs and molecular imprinting technique.

Thermo-sensitive imprinted polymer embedded carbon dots using epitope approach.

A new type of thermo-sensitive receptor carbon dots/SiO2/molecularly imprinted polymer (CDs/SiO2/MIP) was prepared by surface imprinting procedure and the epitope approach. The synthetic CDs/SiO2/MIP was able to selectively capture target protein with fluorescence quenching via the special interaction between them and the recognition cavities. The receptor exhibited the linear fluorescence quenching to cytochrome c (cyt c) in the range of 0.1-40 µM, and the detection limit was 89 nM. The precision for five replicate detection of cyt c at 20 µM was 3.11%. Moreover, the receptor owned the temperature-sensitive element that allowed for swelling and shrinking in response to temperature changes to realize recognition of the target cytochrome c. The proposed strategy revealed the feasibility of fabrication of a thermo-sensitive imprinted polymer based on CDs and surface imprinting procedure and the epitope approach.