The mechanism of acid resistance by ornithine decarboxylase in Trichinella spiralis.

Trichinella spiralis is a zoonotic parasite with worldwide distribution that can seriously harm human health and animal husbandry. Ornithine decarboxylase is a component of the acid resistance (AR) system in Escherichia coli. The aim of this study was to investigate the role that T. spiralis ornithine decarboxylase (TsODC) plays in the acid resistance mechanism of T. spiralis. This study involved assessing the transcription and expression of TsODC in worms under acidic conditions. According to mRNA sequences published by NCBI and the results of molecular biology experiments, the complete TsODC sequence was cloned and expressed. rTsODC had good immunogenicity, and immunofluorescence analysis revealed that TsODC was principally localized on the surface tissues of the nematode, especially at the head and tail. qRT‒PCR and Western blotting analysis indicated that the relative expression levels of TsODC mRNA and protein were highest when cultured at pH 2.5 for 2 h. The muscle larvae (ML) of T. spiralis were treated with curcumin and rapamycin, as well as arginine and TsODC polyantisera. The expression levels of TsODC mRNA and protein were significantly increased by arginine and suppressed by curcumin and rapamycin. After reducing the amount of TsODC, the relative expression of TsODC mRNA and the survival rate of T. spiralis ML were both reduced when compared to these values in the phosphate-buffered saline (PBS) group. The results indicated that TsODC is a member of the T. spiralis AR system and different treatments on TsODC have different effects; thus, these treatments might be a new way to prevent T. spiralis infection.

Runx2 acts downstream of C/EBPß to regulate the differentiation of uterine stromal cells in mice.

Although Runx2 is involved in the regulation of cellular differentiation, its physiological roles in the differentiation of uterine stromal cells during decidualization still remain unknown. The aim of this study was to examine the expression, regulation and function of Runx2 in mouse uterus during decidualization. The results showed that Runx2 was highly expressed in the decidua and oil-induced decidualized cells. In the uterine stromal cells, recombinant human Runx2 (rRunx2) could induce the expression of Prl8a2 and Prl3c1 which are two well-known differentiation markers for decidualization, while inhibition of Runx2 with specific siRNA reduced their expression. Further study found that rRunx2 could improve the expression of Prl8a2 and Prl3c1 in the C/EBPß siRNA-transfected stromal cells. In the stromal cells, cAMP analogue 8-Br-cAMP could induce the expression of Runx2. Moreover, the induction was blocked by PKA inhibitor H89. Simultaneously, attenuation of C/EBPß with siRNA could also reduce the cAMP-induced Runx2 expression. Furthermore, siRNA-mediated silencing of Runx2 expression alleviated the effects of cAMP on the differentiation of stromal cells. Runx2 might act downstream of C/EBPß to regulate the expression of Cox-2, Vegf and Mmp9 in the uterine stromal cells. Collectively, Runx2 may play an important role during mouse decidualization.

Differential expression and regulation of Runx1 in mouse uterus during the peri-implantation period.

Runx1 transcription factor is a key developmental regulator. However, little is known about the effects of Runx1 on embryo implantation and decidualization. The aim of this study is to examine the expression and regulation of Runx1 in mouse uterus during the peri-implantation period. There was no evident Runx1 mRNA signal on days 1-4 of pregnancy. On day 5 of pregnancy, Runx1 mRNA was mainly localized in the subluminal stroma surrounding the implanting blastocyst. A similar result was observed in the estrogen-activated implantation uterus. Simultaneously, a high level of Runx1 mRNA expression was detected on days 6-8 of pregnancy and under artificial decidualization. 8-Br-cAMP could induce the expression of Runx1 mRNA in the uterine stromal cells. Moreover, the induction was obviously blocked by PKA inhibitor H89. Inhibition of Runx1 with specific siRNA could decrease the proliferation of stromal cells and expression of decidual markers Prl8a2 and Prl3c1 in the uterine stromal cells. Further study found that inhibition of Runx1 could also suppress the expression of Cox-2, mPGES-1 and Mmp2 genes in uterine stromal cells. Estrogen and progesterone could induce the expression of Runx1 mRNA in ovariectomized mouse uterus and uterine stromal cells. Taken together, these data suggest that Runx1 may play an important role during mouse decidualization.

Expression and regulation of Runx3 in mouse uterus during the peri-implantation period.

The aim of this study was to investigate the differential expression and regulation of Runt-related transcription factor 3 (Runx3) in mouse uterus during early pregnancy and its regulation by steroid hormones using in situ hybridization. There was a low level of the Runx3 mRNA expression in the mouse uterus on days 1-4 of pregnancy. On day 5 when embryo implanted, Runx3 mRNA signal was obviously observed in the stromal cells surrounding the implanting blastocyst. From day 6 to 8 of pregnancy, Runx3 mRNA was highly expressed in the decidual cells and mesometrial decidual beds. Similarly, Runx3 mRNA was strongly expressed in decidualized cells under artificial decidualization. Compared with the delayed uterus, a high level of Runx3 mRNA signal was detected in the uterus with activated implantation. In the ovariectomized mouse uterus, estrogen could induce the expression of Runx3, while progesterone had no effects. These results suggest that Runx3 may play an important role during mouse implantation and decidualization. Estrogen can induce the expression of Runx3 in the ovariectomized mouse uterus.