CircEML1 facilitates the steroid synthesis in follicular granulosa cells of chicken through sponging gga-miR-449a to release IGF2BP3 expression.

Non-coding RNAs (ncRNAs) induced competing endogenous RNAs (ceRNA) play crucial roles in various biological process by regulating target gene expression. However, the studies of ceRNA networks in the regulation of ovarian ovulation processing of chicken remains deficient compared to that in mammals. Our present study revealed that circEML1 was differential expressed in hen's ovarian tissues at different ages (15 W/20 W/30 W/68 W) and identified as a loop structure from EML1 pre-mRNA, which promoted the expressions of CYP19A1/StAR and E2/P4 secretion in follicular granulosa cells (GCs). Furthermore, circEML1 could serve as a sponge of gga-miR-449a and also found that IGF2BP3 was targeted by gga-miR-449a to co-participate in the steroidogenesis, which possibly act the regulatory role via mTOR/p38MAPK pathways. Meanwhile, in the rescue experiment, gga-miR-449a could reverse the promoting role of circEML1 to IGF2BP3 and steroidogenesis. Eventually, this study suggested that circEML1/gga-miR-449a/IGF2BP3 axis exerted an important role in the steroidogenesis in GCs of chicken.

Adiponectin modulates steroid hormone secretion, granulosa cell proliferation and apoptosis via binding its receptors during hens' high laying period.

Adiponectin is an important adipocytokine and plays the roles in multiple metabolic processes via binding its receptors - AdipoR1 and AdipoR2, which has also been found to participate in the regulation of the reproductive system of animals, in particular by influencing the secretion of ovarian steroid hormones. To further investigate the expression of adiponectin and its receptors in follicles after in vitro incubation, and their role in the steroid synthesis of laying hens' ovaries, we performed qRT-PCR and ELISA to detect the expressions of AdipoQ, AdipoR1, and AidpoR2, and determined the key genes involved in steroidogenesis and the secretion of estradiol (E2) and progesterone (P4) through the in vitro activation of adiponectin (AipoRon) and overexpression or knockdown of AdipoR1 and AdipoR2. Our results revealed that adiponectin and its receptors wildly exist in follicles and granulosa cells, and AdipoRon (5 and 10 µg/mL) had no effect on granulosa cell proliferation and apoptosis but significantly stimulated the secretion of adiponectin and its receptors in granulosa cells after incubation for 24 h. Furthermore, AdipoRon could significantly stimulate the secretion of P4 and inhibit E2 level compared to those of the control group through modulating the key genes expression of steroidogenesis (CYP19A1, StAR, CYP11A1, FSHR, and LHR). The secretion of E2 was also decreased in granulosa cells by the treatments of overexpression and knockdown of AdipoR1/2, however, there was no difference in terms of the level of P4 and StAR expression between them if there was overexpression or knockdown of AdipoR1/2. In addition, it was shown that the secretion of E2 only exhibits a marked drop if co-processing 10 µg/mL AdipoRon and pGMLV AdipoR2 compared to single treatments. Taken together, the study highlighted the role of adiponectin and its receptors in the regulation of steroid synthesis and secretion in ovarian granulosa cells in laying hens.

[Effect of schisandrin B on lung mRNA expression of transforming growth factor-beta1 signal transduction molecule in rat lungs exposed to silica].

OBJECTIVE: To investigate the effects of schisandrin B (Sch-B) on expression of transforming growth factor-beta1 (TGF-beta1) and signal transduction molecule mRNA in rat lungs exposed to SiO2, and explore the intervention mechanism of Sch-B on pulmonary fibrosis induced by SiO2. METHODS: Ninety six Wistar rats were randomly divided into control (normal saline) group, SiO2 group and SiO2 plus Sch-B group. The rats were exposed to SiO2 by direct tracheal instillation to establish the silicotic animal models. SiO2 group and SiO2 plus Sch-B group were treated with 1 ml SiO2 (50 mg/ml) for each rat From the first day after model establishment, SiO2 plus Sch-B group were orally given Sch-B (80 mg/kg) a day, control group and silica group were orally given olive oil. On the 3rd, 7th, 14th and 28th days after treatment, 8 rats in each group were sacrificed and samples were collected. The histo-pathological examination of lung was performed by HE staining. The expression levels of TGF-beta1, TGF-betaR II and Smad4 mRNA in the lung tissues were detected by RT-PCR. RESULTS: The results of histo-pathological examination showed that in SiO2 group, lung tissues were injured obviously; the alveolar inflammation with alveolus interval edema and inflammation cell infiltration appeared on the 3rd and 7th days; the alveolus interval became thicker, became thicker, fibroblast and collagen matrix increased markedly on 14th day; the alveolar structure was damaged, alveolar wall thickened obviously, collagen aggravation and pulmonary fibrosis displayed on 28th day. The alveolar inflammation and pulmonary fibrosis in SiO2 plus Sch-B group were significantly less than those in SiO2 group. The expressions levels of TGF-beta1 TGF-betaR II and Smad4 mRNA (TGF-1beta: 1.03 +/- 0.31, 1.33 +/- 0.39,1.08 +/- 0.26, 0.82 +/- 0.16, TGF-betaR II: 0.65 +/- 0.11, 0.80 +/- 0.16, 0.83 +/- 0.24, 0.62 +/- 0.15, Smad4:0.87 +/- 0.15, 0.68 +/- 0.11, 0.78 +/- 0.19, 0.30 +/- 0.08) in SiO2 group were significantly higher than those in the control group (TGF-beta1:0.59 +/- 0.22, 0.55 +/- 0.25, 0.56 +/- 0.20, 0.55 +/- 0.12, TGR-betaR II :0.28 +/- 0.13, 0.31 +/- 0.15, 0.34 +/- 0.15, 0.27 +/- 0.09, Smad4:0.23 +/- 0.11, 0.40 +/- 0.12, 0.39 +/- 0.12, 0.18 +/- 0.06) (P < 0.01 or P < 0.05), but the expression level of TGF-beta1 mRNA was the highest on the 7th day. The expression levels of TGF-beta1 and Smad4 mRNA (TGF-beta1:0.68 +/- 0.28, 0.88 +/- 0.25, 0.75 +/- 0.11, 0.61 +/- 0.14,Smad4:0.25 +/- 0.12, 0.45 +/- 0.09, 0.44 +/- 0.07, 0.21 +/- 0.04) in SiO2 plus Sch-B group were significantly lower than those in SiO2 group (P < 0.01 or P < 0.05 ), but there were no significant differences of the TGFbetaR II mRNA expression levels between SiO2 group and SiO2 plus Sch-B group. CONCLUSION: Sch-B can reduce the pulmonary fibrosis induced by SiO2 through inhibition of the mRNA express of TGF-beta1 and Smad4 in the lung tissue, modulating the TGF-beta1/Smad4 signal transduction pathway and inhibiting the target gene activation.