Effect of genetic polymorphisms on the pharmacokinetics of gefitinib in healthy Chinese volunteers.

Gefitinib is the first-generation drug of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) metabolised by the cytochrome P450 and transported by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). In the present study, the pharmacokinetics of gefitinib in healthy Chinese volunteers was investigated and the effect of genetic polymorphisms on its variability was evaluted.Forty-five healthy volunteers were administered a single dose of gefitinib and the blood samples were used for quantifying the concentration of gefitinib and genotyping fifteen single-nucleotide polymorphisms of cytochrome P450 enzymes (CYP3A4, CYP3A5, CYP2D6, CYP2C9 and CYP2C19) and drug transporters (ABCB1 and ABCG2).CYP3A5*3 (rs776746) polymorphism showed a significant influence, with higher gefitinib AUC0-t in carrier of CC genotype than in CT/TT genotype (BH-adjusted p value <0.05). For CYP2C9*3 (rs1057910), significant differences in pharmacokinetics of gefitinib were detected between carriers of AA and AC genotypes, with higher AUC0-t, AUC0-∞ and Cmax in carrier of AC genotype than in AA gen-otype (BH-adjusted p value <0.05). No associations were found between SNPs in CYP3A4, CYP2D6, CYP2C19, ABCB1, ABCG2 and the pharmacokinetics of gefitinib.The SNPs in CYP3A5*3 (rs776746) and CYP2C9*3 (rs1057910) were found to be associated with altered gefitinib pharmacokinetics in healthy Chinese volunteers.

The C-type lectin IML-10 promotes hemocytic encapsulation by enhancing aggregation of hemocytes in the Asian corn borer Ostrinia furnacalis.

C-type lectins participate in hemocytic encapsulation as pattern recognition receptors; however, the molecular mechanisms underlying their function remain unknown. In this study, we determined that the encapsulation-promoting function of a C-type lectin, IML-10, may be related to its interaction with hemocytes in the agricultural pest Ostrinia furnacalis. IML-10 possesses two carbohydrate-recognition domains (CRDs) containing EPN and QPD motifs with 4 and 6 conserved cysteine residues, respectively. IML-10 was found to mainly be secreted by the fat body into the larval plasma, and its expression was induced by Sephadex A-25 beads. Anti-IML-10 antibodies inhibited encapsulation-promoting function of IML-10 in the larval plasma. The encapsulation rate of Sephadex A-25 beads decreased from approximately 90%-30% when expression of IML-10 in O. furnacalis larvae was inhibited by RNAi. Moreover, the Sephadex bead-encapsulating ability of hemocytes decreased to almost zero in O. furnacalis larvae with IML-10 knocked out by CRISPR/Cas9, with IML-10 expression clearly decreasing compared to that of the control. Similar to the larval plasma, recombinant IML-10 promoted Sephadex bead encapsulation by hemocytes. Immunohistochemistry analysis showed that IML-10 was able to bind to the surface of both granulocytes and plasmatocytes but not to Sephadex beads as foreign objects. Furthermore, recombinant IML-10 promoted hemocyte aggregation but not adhesion. Therefore, we speculate that IML-10 binds to the surface of hemocytes to promote their aggregation and further improve their encapsulation capacity. These results contribute to clarifying the function of insect C-type lectins in encapsulation.

LSD1 mediates microbial metabolite butyrate-induced thermogenesis in brown and white adipose tissue.

OBJECTIVE: The gut microbiota regulates thermogenesis to benefit metabolic homeostasis at least partially via its metabolite butyrate, and the underlying mechanisms of this regulation are still unclear. In this study, we aim to investigate the role of lysine specific demethylase (LSD1), a histone demethylase and important regulator of thermogenesis, in mediating gut microbial metabolite butyrate regulation of thermogenesis. METHODS: The antibiotic cocktail (ABX) was administrated to deplete gut microbiota. Adipose-specific LSD1 knockout mice (LSD1 aKO) were generated by crossing LSD1-lox/lox with adiponectin-cre mice and sodium butyrate and dietary fiber inulin was administrated through oral-gavage. Primary stromal vascular cells were isolated from adipose tissues and differentiated to adipocytes for studying butyrate effects on adipocyte thermogenesis. RESULTS: The antibiotic cocktail (ABX)-mediated depletion of the gut microbiota in mice downregulated the expression of LSD1 in both brown adipose tissue (BAT) and subcutaneous white adipose tissue (scWAT) in addition to uncoupling protein 1 (UCP1) and body temperature. Gavage of the microbial metabolite butyrate in ABX-treated mice reversed the thermogenic functional impairment and LSD1 expression. The adipose-specific ablation of LSD1 in mice attenuated the butyrate-mediated induction of thermogenesis and energy expenditure. Notably, our results showed that butyrate directly increased the expression of LSD1 and UCP1 as well as butyrate transporter monocarboxylate transporter 1 (MCT1) and catabolic enzyme acyl-CoA medium-chain synthetase 3 (ACSM3) in ex vivo cultured adipocytes. The inhibition of MCT1 blocked the effects of butyrate in adipocytes. Furthermore, the butyrate-mediated prevention of diet-induced obesity (DIO) through increased thermogenesis was attenuated in LSD1 aKO mice. Moreover, after gavaging HFD-fed mice with the dietary fiber inulin, a substrate of microbial fermentation that rapidly produces butyrate, thermogenesis in both BAT and scWAT was increased, and DIO was decreased; however, these beneficial metabolic effects were blocked in LSD1 aKO mice. CONCLUSIONS: Together, our results indicate that the microbial metabolite butyrate regulates thermogenesis in BAT and scWAT through the activation of LSD1.

Propionate promotes intestinal lipolysis and metabolic benefits via AMPK/LSD1 pathway in mice.

Dietary fibers and their microbial fermentation products short chain fatty acids promote metabolic benefits, but the underlying mechanisms are still unclear. Recent studies indicate that intestinal lipid handling is under regulatory control and has broad influence on whole body energy homeostasis. Here we reported that dietary inulin and propionate significantly decreased whole body fat mass without affecting food intake in mice fed with chow diet. Meanwhile, triglyceride (TG) content was decreased and lipolysis genes expressions, such as adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL) and lysosomal acid lipase (LAL) were elevated in the jejunum and ileum of inulin and propionate treated mice. In vitro studies on Caco-2 cells showed propionate directly induced enterocyte ATGL, HSL and LAL gene expressions and decreased TG content, via activation of phosphorylation of AMP-activated protein kinase (p-AMPK) and lysine specific demethylase 1 (LSD1). Moreover, inulin and propionate could increase intestinal lipolysis under high fat diet (HFD) fed condition which contributed to the prevention of HFD-induced obesity. Our study suggests dietary fiber inulin and its microbial fermentation product propionate can regulate metabolic homeostasis through regulating intestinal lipid handling, which could provide a novel therapeutic target for both prevention and treatment of obesity.