We studied whether polymorphisms in the UGT1A8, UGT1A9, and UGT2B7 genes, the enzymes producing the phenolic (MPAG) and acyl (AcMPAG) glucuronides of mycophenolic acid (MPA), could contribute to the interindividual variation observed in mycophenolate mofetil (MMF) pharmacokinetics (PKs). This study enrolled 17 healthy volunteers with no polymorphisms (controls) and 17 carriers of UGT1A9 -275/-2152 selected among 305 individuals genetically screened for UDP-glucuronosyltransferase (UGT) polymorphisms. Additional investigative groups included carriers of UGT1A8*2 (A173G) (n=9), UGT1A8*3 (C277Y) (n=4), and UGT1A9*3 (M33T) (n=5). Genetic analysis also included UGT2B7 to detect UGT2B7*2 (His268Tyr) and the promoter haplotype -1248A>G, -1241T>C, -1054T>C, -842G>A, -268A>G, -102T>C. Kinetics were measured in plasma and urine after a single 1.5 g oral dose of MMF, by high-performance liquid chromatography coupled with tandem mass spectrometry, over 12 h after drug intake. Compared to controls, MPA exposure was significantly lower for UGT1A9 -275/-2152 carriers, with no significant changes in MPAG. The estimates of enterohepatic (re)cycling (area under the concentration-time curve (AUC6-12 h/AUC0-12 h)) were significantly lower for MPA, MPAG, and AcMPAG in UGT1A9 -275/-2152 subjects. Compared with controls, UGT1A9*3 carriers had higher MPA and AcMPAG exposure, whereas homozygosity for the UGT1A8*2 allele and heterozygosity for UGT1A8*3 allele had no impact on MPA PKs. Compared with UGT2B7*1/*1 individuals (n=10), UGT2B7*2/*2 subjects (n=17) presented significantly higher free MPA C(max) values and elevated free and total MPA. Results indicate that after a single oral dose of MMF in healthy volunteers, specific UGT genotypes significantly alter MPA PKs and this clearly warrants additional studies with complete and detailed genetic profiling of UGT1A8, UGT1A9, and UGT2B7 genes.

Multilocus sequence typing previously identified three predominant sequence types (STs) of Streptococcus suis serotype 2: ST1 strains predominate in Eurasia while North American (NA) strains are generally ST25 and ST28. However, ST25/ST28 and ST1 strains have also been isolated in Asia and NA, respectively. Using a well-standardized mouse model of infection, the virulence of strains belonging to different STs and different geographical origins was evaluated. Results demonstrated that although a certain tendency may be observed, S. suis serotype 2 virulence is difficult to predict based on ST and geographical origin alone; strains belonging to the same ST presented important differences of virulence and did not always correlate with origin. The only exception appears to be NA ST28 strains, which were generally less virulent in both systemic and central nervous system (CNS) infection models. Persistent and high levels of bacteremia accompanied by elevated CNS inflammation are required to cause meningitis. Although widely used, in vitro tests such as phagocytosis and killing assays require further standardization in order to be used as predictive tests for evaluating virulence of strains. The use of strains other than archetypal strains has increased our knowledge and understanding of the S. suis serotype 2 population dynamics.

In this review paper, literature data on pre- and postnatal eye development are compared between humans and nonclinical species that are commonly used for human safety assessment, namely, mouse, rat, rabbit, dog, minipig, and nonhuman primates. Some new data on rat and minipig ocular development are also included. This compiled information can be helpful for species selection in juvenile toxicity studies or assist in the interpretation of (non)clinical data during pediatric drug development. Despite some differences in developmental windows and anatomical peculiarities, such as the lack of a fovea centralis in nonprimate species or the presence of a nictitating membrane in some nonclinical species, the functioning and development of the eye is strikingly similar between humans and other mammals. As such, all commonly used nonclinical species appear to be relatively good models for human eye development, although some practical constraints such as size may be a limiting factor. Birth Defects Research 109:1540-1567, 2017. © 2017 Wiley Periodicals, Inc.

UGT1A4 is primarily expressed in the liver and exhibits catalytic activities for various drugs. Amongst the few UGT1A4 polymorphisms evaluated, studies support the alteration of UGT1A4-mediated glucuronidation by a few variations including the Pro24Thr and Leu48Val variants (referred to as UGT1A4*2 and *3). We therefore investigated genetic mechanisms that might contribute to interindividual variation in UGT1A4 expression and activity. The UGT1A4 gene was sequenced from −4963 bp relative to the ATG to 2000 bp after the first exon in 184 unrelated Caucasians and African-Americans. We identified a large number of genetic variations, including 13 intronic, 39 promoter, as well as 14 exonic polymorphisms, with 10 that lead to amino-acid changes. Of the nucleotide variations found in the −5kb promoter region, 5 are located in the proximal region (first 500 bp), and positioned in putative HNF-1 and OCT-1 binding sites. Four of these variants, placed at −163, −219, −419 and −463, are in complete linkage disequilibrium with the Leu48Val coding region variant and with several variants in the upstream region of the promoter. Transient transfections of reference and variant promoter constructs (from position −500 to +1) in different cell lines with or without co-expression of HNF-1 and/or OCT-1, demonstrated limited effect of these variations. Additional functional studies on promoter variants are still required to predict their potential influence on UGT1A4 expression in vivo. Besides, several coding variants significantly modified the enzyme kinetics for tamoxifen and Z-4-hydroxytamoxifen (Val48, Asp50, Gln56, Phe176, Asn250, Leu276) and are expected to have a potential in vivo effect.

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ABSTRACT:Tissue iron overload constitutes a major health problem for people who require regular blood transfusions, such as those with ␤-thalassemia major. Deferiprone is a hydroxypyridinone iron chelator used therapeutically to remove this excess iron and prevent tissue damage. Deferiprone is metabolized by UDP-glucuronosyltransferases (UGTs) into deferiprone 3-O-glucuronide (DG), but a systematic evaluation of the contribution of individual human UGTs and the impact of genetic variations of UGTs have not been conducted. Sixteen human UGT1A and UGT2B were studied for deferiprone glucuronidation, and their clearances were compared in human tissue samples. DG was measured by liquid chromatography coupled with mass spectrometry. DG was primarily produced in vitro by UGT1A6, and a second glucuronide metabolite was discovered. UGT1A6, as well as liver and kidney human microsomes, had similar kinetic profiles and clearance (Cl int ‫؍‬ 1.4-3.0 l/min/mg), but clearance by intestinal microsomes was much lower (0.04 l/min/mg). Binding of deferiprone to microsomal preparations was not significant. Genetic variants of UGT1A6 had K m values similar to the reference protein (UGT1A6*1), but their V max values were reduced by 25 to 70%. The UGT1A6 splice variant isoform 2, detected in the liver and kidney, had no transferase activity for deferiprone. When UGT1A6_i2 was coexpressed with the classic UGT1A6_i1 isoform, velocity was reduced for deferiprone but remained similar for 4-nitrophenol or serotonin glucuronidation. In conclusion, deferiprone glucuronidation seems to depend almost totally on UGT1A6, especially in the liver. Genetic variations and differences in the expression of splice variants represent a potential source of variation in deferiprone metabolism.

The paternal environment is thought to influence sperm quality and future progeny may also be impacted. We hypothesized that prenatal exposure to environmentally-relevant contaminants impairs male reproduction, altering embryo gene expression over multiple generations. Folic acid (FA) can improve sperm quality and pregnancy outcomes, thus we further hypothesized that FA mitigates the contaminants. Sprague-Dawley F0 female rats treated with persistent organic pollutants (POPs) or corn oil and fed basal or supplemented FA diets, then used to yield four generations of litters. Only F0 females received POPs and/or FA treatments. In utero POPs exposure altered sperm parameters in F1, which were partly rescued by FA supplementation. Paternal exposure to POPs reduced sperm quality in F2 males, and the fertility of F3 males was modified by both POPs and FA. Ancestral FA supplementation improved sperm parameters of F4 males, while the POPs effect diminished. Intriguingly, F3 males had the poorest pregnancy outcomes and generated the embryos with the most significantly differentially expressed genes. Early-life exposure to POPs harms male reproduction across multiple generations. FA supplementation partly mitigated the impact of POPs. The two-cell embryo transcriptome is susceptible to paternal environment and could be the foundation for later pregnancy outcomes.

The pathogenesis of Streptococcus suis infection, a major swine and human pathogen, is only partially understood and knowledge on the host adaptive immune response is critically scarce. Yet, S. suis virulence factors, particularly its capsular polysaccharide (CPS), enable this bacterium to modulate dendritic cell (DC) functions and potentially impair the immune response. This study aimed to evaluate modulation of T cell activation during S. suis infection and the role of DCs in this response. S. suis-stimulated total mouse splenocytes readily produced TNF-α, IL-6, IFN-γ, CCL3, CXCL9, and IL-10. Ex vivo and in vivo analyses revealed the involvement of CD4+ T cells and a Th1 response. Nevertheless, during S. suis infection, levels of the Th1-derived cytokines TNF-α and IFN-γ were very low. A transient splenic depletion of CD4+ T cells and a poor memory response were also observed. Moreover, CD4+ T cells secreted IL-10 and failed to up-regulate optimal levels of CD40L and CD69 in coculture with DCs. The CPS hampered release of several T cell-derived cytokines in vitro. Finally, a correlation was established between severe clinical signs of S. suis disease and impaired antibody responses. Altogether, these results suggest S. suis interferes with the adaptive immune response.