Background: Granulosa cell (GC) apoptosis is the main cause of follicular atresia, and oxidative stress is involved in this process. Results: GC apoptosis is caused by FoxO1 activity in oxidative stress. Conclusion: FoxO1 is critical in oxidative stress-induced GC apoptosis. Significance: Our results detail the mechanism of follicular atresia and indicate that FoxO1 is a potential target in preventing follicular atresia from oxidative stress.

DNA structural variation (SV) comprises a major portion of genetic diversity, but its biological impact is unclear. We propose that the genetic history and extraordinary phenotypic variation of dogs make them an ideal mammal in which to study the effects of SV on biology and disease. The hundreds of existing dog breeds were created by selection of extreme morphological and behavioral traits. And along with those traits, each breed carries increased risk for different diseases. We used array CGH to create the first map of DNA copy number variation (CNV) or SV in dogs. The extent of this variation, and some of the gene classes affected, are similar to those of mice and humans. Most canine CNVs affect genes, including disease and candidate disease genes, and are thus likely to be functional. We identified many CNVs that may be breed or breed class specific. Cluster analysis of CNV regions showed that dog breeds tend to group according to breed classes. Our combined findings suggest many CNVs are (1) in linkage disequilibrium with flanking sequence, and (2) associated with breed-specific traits. We discuss how a catalog of structural variation in dogs will accelerate the identification of the genetic basis of canine traits and diseases, beginning with the use of whole genome association and candidate-CNV/gene approaches.

Rotaviruses are the leading cause of severe diarrhea in infants and young children worldwide. Thus, the development of an effective rotavirus vaccine is a major public health goal. This study was performed to identify the gene or genes responsible for rotavirus virulence or host range restriction and attenuation in a natural host. Such knowledge could have an important bearing on the selection of candidate live vaccine strains. We addressed this issue by analyzing the response of gnotobiotic piglets to orally administered porcine x human rotavirus reassortants. It was possible to determine (i) which porcine rotavirus genes were required for the induction of diarrhea, and (ii) which human rotavirus genes are associated with the host range restriction because the parental porcine rotavirus (SB-1A strain) caused diarrhea in piglets, whereas the parental human rotavirus (DS-1 strain) was attenuated in piglets. Substitution of the 3rd (VP3) or 4th (VP4) or 9th (VP7) or 10th (NS28 (NSP4)) gene of the avirulent human strain for the corresponding gene of porcine rotavirus that was virulent for gnotobiotic piglets yielded viral reassortants that failed to induce diarrhea. Further analysis indicated that reassortants which possessed only one, two, or three of these porcine rotavirus genes on a background of human rotavirus genes also failed to induce diarrhea. However, diarrhea was induced when all four of these porcine rotavirus genes were included in a reassortant in which the remaining seven genes were derived from the human rotavirus. These observations suggest that it may be possible to attenuate wild-type human rotavirus strains that are virulent for humans by selective genetic reassortment with an animal rotavirus strain that is attenuated for humans.

As a canalicular bile acid effluxer, bile salt export pump (BSEP) plays a vital role in maintaining bile acid homeostasis. BSEP deficiency leads to severe cholestasis and hepatocellular carcinoma (HCC) in young children. Regardless of the etiology, chronic inflammation is the common pathological process for HCC development. Clinical studies showed that bile acid homeostasis is disrupted in HCC patients with elevated serum bile acid level as a proposed marker for HCC. However, the underlying mechanisms remain largely unknown. In this study, we found that BSEP expression was severely diminished in HCC tissues and markedly reduced in adjacent non-tumor tissues. In contrast to mouse, human BSEP was regulated by farnesoid x receptor (FXR) in an isoform-dependent manner. FXRα2 exhibited a much more potent activity than FXRα1 in transactivating human BSEP in vitro and in vivo. The decreased BSEP expression in HCC was associated with altered relative expression of FXRα1 and FXRα2. The FXRα1/FXRα2 ratios were significantly increased with undetectable FXRα2 expression in one third of the HCC tumor samples. Similar correlation between BSEP and FXR isoform expression was confirmed in hepatoma Huh 7 and HepG2 cells. Further studies showed that intrahepatic proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were significantly elevated in HCC tissues. Treatment of Huh 7 cells with IL-6 and TNF-α resulted in a marked increase in the FXRα1/FXRα2 ratio concurrent with a significant decrease in BSEP expression. In conclusion, BSEP expression was severely diminished in HCC patients associated with alteration of FXR isoform expression induced by inflammation, and the restoration of BSEP expression through suppressing inflammation in the liver may re-establish the bile acid homeostasis.