Circ_0001666 upregulation promotes intestinal epithelial cell fibrosis in pediatric Crohn's disease via the SRSF1/BMP7 axis.

The epithelial-mesenchymal transition (EMT) is closely associated with Crohn's disease (CD) related intestinal fibrosis, a condition whose prevalence is increasing annually among children. Recently, the CD marker gene microarray screening revealed an upregulation of circ_0001666 in the colon tissues of CD patients, but its underlying mechanisms remain unclear. In this study, we explored the molecular mechanism of circ_0001666 in regulating EMT-mediated fibrosis in CD in vitro. The levels of circ_0001666 and EMT-associated proteins were assessed in CD clinical samples, and a CD cell model was established using TGF-ß1 to induce human intestinal epithelial cells (HIECs). Additionally, the expression levels of genes and proteins related to EMT and fibrosis were analyzed by quantitative real-time PCR and western blot, cell migration, and invasion were assessed via wound healing assay and transwell, respectively, and RNA pull-down and RNA immunoprecipitation assays were performed to verify the relationship between SRSF1 and BMP7 or circ_0001666. Circ_0001666 was overexpressed in the intestinal mucosal tissues of CD patients and was positively correlated with EMT. Silencing circ_0001666 inhibited the migration, invasion, EMT, and fibrosis of HIECs induced by TGF-ß1. Mechanistically, circ_0001666 regulated BMP7 expression by interacting with SRSF1. Furthermore, the effects of inhibiting circ_0001666 on HIECs could be partially reversed by overexpressing SRSF1 or silencing BMP7. Collectively, circ_0001666 regulates TGF-ß1-induced HIEC migration, invasion, EMT, and fibrosis. Circ_0001666 also promoted EMT-mediated fibrosis by interacting with SRSF1 to accelerate BMP7 mRNA decay. These findings provide new insights into the pathogenesis of CD and suggest that circ_0001666 might be a potential therapeutic target for CD.

A new species and a new series of Elatostema (Urticaceae) from south-western China.

The new series ElatostemasectionWeddellia series Xingyiensia L.D. Duan & D.H. Yin (Urticaceae) is described. In addition, its new species Elatostemaxingyiense L.D. Duan & D.H. Yin, endemic to Guizhou Province, is also described and illustrated with photographs. The new series is morphologically similar to series Melanocarpa W.T. Wang and series Sublinearia W.T. Wang. The new species is most similar to E.melanocarpum, E.sublineare, E.obscurinerve, E.langicuspe and E.youyangense in morphology, but can be visibly distinguished by a combination of characters, including leaf vein, male inflorescences, female inflorescences and persistent tepals.

[Establishment of Duplex PCR for Identifying Metagonimus yokogawai and Haplorchis taichui].

OBJECTIVE: To develop a duplex PCR method for identifying Metagonimus yokogawai and Haplorchis taichui. METHODS: ITS1 sequences of M. yokogawai and H. taichui, as well as those of their homologous species were obtained from GenBank, and two sets of specific primer pairs for M. yokogawai and H. taichui were designed accordingly using Primer Premier 5.0 software. PCR reaction system and conditions were optimized. The established duplex PCR method was applied in a pool of M. yokogawai, H. taichui, and 17 related species to examine its specificity. Sensitivity was evaluated through serial dilutions of plasmids containing their specific sequences. Finally, the duplex PCR was applied to identify M. yokogawai and H. taichui among trematodes collected from the viscera of 47 cats and 40 dogs to test its practicality. RESULTS: The duplex PCR method amplified target sequences of M. yokogawai and H. taichui, generating 648 bp and 279 bp products, respectively. No cross reaction was found with the following 17 related species: Haplorchis pumilio, Clonorchis sinensis, Pharyngostomum cordatum, the metacercaria of Metorchis sp. and Exorchis sp., Echinochasmus liliputanus, Echinochasmus perfoliatus, Echinostoma friedi, Hypoderaeum conoideum, Holostephanus sp., Diplodiscus sp., Anisakis sp., Metorchis orientais, Paragonimus westermani, Watsonius watsoni, Notocotylus sp. and Hysterothylacium sp, indicating a high specificity of this method. The detection limits for DNAs of M. yokogawai and H. taichui were 1.49 x 10(-1) pg and 1.14 x 10(-1) pg, suggesting a good sensitivity for this method. Further, the duplex PCR successfully identified M. yokogawai and H. taichui from cat and dog viscera, with no cross amplification of other trematodes. CONCLUSION: The duplex PCR is effective in identifying Metagonimus yokogawai and Haplorchis taichui.