CD4+ T cell responses are critical for the pathogenesis of Helicobacter pylori infection. The present study evaluated the role of the Th17 subset in H. pylori infection. H. pylori infection induced significant expression of IL-17 and IFN-g in mouse gastric tissue. IL-23 and IL-12 were increased in the gastric tissue and in H. pylori-stimulated macrophages. Cell responses were examined by intracellular staining for IFN-g, IL-4, and IL-17. Mice infected with H. pylori developed a mixed Th17/Th1 response; Th17 responses preceded Th1 responses. Treatment of mice with an anti-IL-17 Ab but not a control Ab significantly reduced the H. pylori burden and inflammation in the stomach. H. pylori colonization and gastric inflammation were also lower in IL-17 2/2 mice. Furthermore, administration of recombinant adenovirus encoding mouse IL-17 increased both H. pylori load and inflammation. Further analysis showed that the Th1 cell responses to H. pylori were downregulated when IL-17 is deficient. These results together suggest that H. pylori infection induces a mixed Th17/Th1 cell response and the Th17/IL-17 pathway modulates Th1 cell responses and contributes to pathology. The Journal of Immunology, 2010, 184: 5121-5129. H elicobacter pylori is a Gram-negative, microaerophilic bacterium that resides extracellularly in the gastric mucosa and infects .50% of the population worldwide. H. pyloriinduced chronic inflammation is the cause of gastritis and peptic ulcers and a risk factor for gastric cancer (1, 2). H. pylori infection causes severe local inflammation in the gastric mucosa. CD3 + CD4 + T cells are increased in infected gastric lamina propria and play important roles in the pathogenesis of persistent H. pylori infection (3). Traditionally, CD4 + T cells are classified into two main classes: Th1 and Th2, on the basis of their cytokine secretion and immune regulatory function. Th1 cells secrete IFN-g, IL-2, and IL-12 and regulate cellular immunity, whereas Th2 cells produce IL-4, IL-5, and IL-13 and mediate humoral responses. To date, studies of immune responses to H. pylori have largely focused on Th1 and Th2 cells, and it is generally accepted that H. pylori infection results in a Th1-dominant response and that gastric inflammation largely depends on Th1 cell responses (3-6); however, IFN-g secretion alone is insufficient to induce gastritis (3). Thus, the detailed mechanism of pathogenesis is not clear. A novel subset of effector T cells, identified by secretion of IL-17, has been defined as Th17 cells. Th17 cells are distinct from Th1 and Th2 cells in their differentiation and function (7,8). TGF-b and IL-6 from activated macrophages/dendritic cells are required for Th17 cell differentiation in murine systems (9), whereas IL-12 and IFN-g promote Th1 cell development and IL-4 primes Th2 cell differentiation. The expansion and survival of Th17 cells are promoted by IL-23 (9), a heterodimeric cytokine composed of a unique p19 subunit and a p40 subunit shared with IL-12 (10). The identification of Th17 cells necessit...

X-box binding protein-1 (XBP-1) is an important regulator of a subset of genes during endoplasmic reticulum (ER) stress. In the current study, we analyzed endogenous XBP-1 expression and localization, with a view to determining the effects of ER stress on the developmental competency of preimplantation embryos in mice. Fluorescence staining revealed that functional XBP-1 is localized on mature oocyte spindles and abundant in the nucleus at the germinal vesicle (GV) stage. However, in preimplantation embryos, XBP-1 was solely detected in the cytoplasm at the one-cell stage. The density of XBP-1 was higher in the nucleus than the cytoplasm at the two-cell, four-cell, eight-cell, morula, and blastocyst stages. Furthermore, RT-PCR analysis confirmed active XBP-1 mRNA splicing at all preimplantation embryo stages, except the one-cell stage. Tunicamycin (TM), an ER stress inducer used as a positive control, promoted an increase in the density of nuclear XBP-1 at the one-cell and two-cell stages. Similarly, culture medium supplemented with 25 mM sorbitol displayed a remarkable increase active XBP-1 expression in the nuclei of 1-cell and 2-cell embryos. Conversely, high concentrations of TM or sorbitol led to reduced nuclear XBP-1 density and significant ER stress-induced apoptosis. Tauroursodeoxycholic acid (TUDCA), a known inhibitor of ER stress, improved the rate of two-cell embryo development to blastocysts by attenuating the expression of active XBP-1 protein in the nucleus at the two-cell stage. Our data collectively suggest that endogenous XBP-1 plays a role in normal preimplantation embryonic development. Moreover, XBP-1 splicing is activated to generate a functional form in mouse preimplantation embryos during culture stress. TUDCA inhibits hyperosmolar-induced ER stress as well as ER stress-induced apoptosis during mouse preimplantation embryo development.

X-box-binding protein 1 (XBP1) is an important regulator of a subset of genes active during endoplasmic reticulum (ER) stress. In the present study, we analyzed XBP1 level and location to explore the effect of ER stress on oocyte maturation and developmental competency of porcine embryos in an in vitro culture system. First, we examined the localization of XBP1 at different meiotic stages of porcine oocytes and at early stages of parthenogenetic embryo development. Fluorescence staining showed that expression of functional XBP1 was weak in mature oocytes and at the 1-, 2-, and 8-cell stages of embryos but abundant at the germinal vesicle (GV), 4-cell, morula, and blastocyst stages. In addition, RT-PCR revealed that both spliced XBP1 (XBP1-s) and unspliced XBP1 (XBP1-u) were expressed at the GV, 4-cell, morula, and blastocyst stages. Tunicamycin, an ER stress inducer, induced active XBP1 protein in nuclei of 4-cell embryos. Next, porcine embryos cultured in the presence of tauroursodeoxycholate, an ER stress inhibitor, were studied. Total cell numbers and the extent of the inner cell mass increased (P < 0.05), whereas the rate of nuclear apoptosis decreased (P < 0.05). Moreover, expression of the antiapoptotic gene BCL2 increased, whereas expression of the proapoptotic genes BCL2L1 (Bcl-xl) and TP53 decreased. The results indicated that inhibition of ER stress enhanced porcine oocyte maturation and embryonic development by preventing ER stress-mediated apoptosis in vitro.

Lysophosphatidic acid (LPA), a member of the phospholipid autacoid family, is present in human follicular fluid. The aim of the present study was to compare the developmental competence of porcine embryos created via in vitro fertilization (IVF) and parthenogenetic activation (PA) in culture medium supplemented with LPA, in comparison with a control group. The effects of LPA on porcine oocyte maturation and pre-implantation embryonic development were also examined. Addition of 10 μM LPA to the oocyte maturation medium significantly increased the proportion of oocytes reaching metaphase I (MI) or metaphase II (MII), and enhanced embryonic developmental potential. When present during oocyte maturation, LPA significantly increased the abundance of phosphorylated ERK1/2 in MI and MII oocytes, showing that LPA enhanced nuclear maturation via activation of the mitogen-activated protein kinase (MAPK) pathway. In addition, Cyclin B1 levels were elevated in MI- and MII-stage oocytes, suggesting that LPA plays a role in both nuclear and cytoplasmic maturation of oocytes. After fertilization, the frequency of polyspermy in embryos obtained using LPA-treated oocytes was less than that in the control group. Further, blastocyst formation and blastocyst cell number were enhanced and apoptosis was reduced upon LPA treatment of embryos created either by IVF and PA. LPA treatment of blastocysts derived by IVF or PA resulted in increased expression of the anti-apoptotic BCL2L1 gene while reducing expression of the pro-apoptotic genes BAX and CASP3. Together, our data indicate that LPA supplementation improves porcine oocyte maturation and subsequent in vitro development of pre-implantation embryos.

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