Protective Effects of Genipin on Gastrointestinal Disorders.

Genipin, an aglycone of geniposide, is a major component of gardeniae fructus, and has been used to treat jaundice, various inflammatory disorders, and liver disease, and has also been used as a natural cross-linking agent. The authors conducted several experiments to evaluate the protective effects of genipin on gastrointestinal disorders, such as, gastritis and gastric ulcers. Genipin showed inhibitory effects against HCl·ethanol-induced acute gastritis and indomethacin-induced gastric ulcers in rats and increased prostaglandin E2 (PGE2) in AGS gastric cancer cell. Genipin had significant effects on aggressive factors, acid-neutralization, and gastric secretion, and inhibited H+/K+-ATPase (a proton pump), which secretes gastric acid. The results obtained indicate that genipin has significant gastroprotective effects and might be useful for treating and preventing gastric lesions.

Protective Effect of Liriodendrin Isolated from Kalopanax pictus against Gastric Injury.

In this study, we investigated the inhibitory activities on gastritis and gastric ulcer using liriodendrin which is a constituent isolated from Kalopanax pictus. To elucidate its abilities to prevent gastric injury, we measured the quantity of prostaglandin E2 (PGE2) as the protective factor, and we assessed inhibition of activities related to excessive gastric acid be notorious for aggressive factor and inhibition of Helicobacter pylori (H. pylori) colonization known as a cause of chronic gastritis, gastric ulcer, and gastric cancer. Liriodendrin exhibited higher PGE2 level than rebamipide used as a positive control group at the dose of 500 µM. It was also exhibited acid-neutralizing capacity (10.3%) and H(+)/K(+)-ATPase inhibition of 42.6% (500 µM). In pylorus-ligated rats, liriodendrin showed lower volume of gastric juice (4.38 ± 2.14 ml), slightly higher pH (1.53 ± 0.41), and smaller total acid output (0.47 ± 0.3 mEq/4 hrs) than the control group. Furthermore liriodendrin inhibited colonization of H. pylori effectively. In vivo test, liriodendrin significantly inhibited both of HCl/EtOH-induced gastritis (46.9 %) and indomethacin-induced gastric ulcer (46.1%). From these results, we suggest that liriodendrin could be utilized for the treatment and/or protection of gastritis and gastric ulcer.

Small non-coding RNA profiling and the role of piRNA pathway genes in the protection of chicken primordial germ cells.

BACKGROUND: Genes, RNAs, and proteins play important roles during germline development. However, the functions of non-coding RNAs (ncRNAs) on germline development remain unclear in avian species. Recent high-throughput techniques have identified several classes of ncRNAs, including micro RNAs (miRNAs), small-interfering RNAs (siRNAs), and PIWI-interacting RNAs (piRNAs). These ncRNAs are functionally important in the genome, however, the identification and annotation of ncRNAs in a genome is challenging. The aim of this study was to identify different types of small ncRNAs particularly piRNAs, and the role of piRNA pathway genes in the protection of chicken primordial germ cells (PGCs). RESULTS: At first, we performed next-generation sequencing to identify ncRNAs in chicken PGCs, and we performed ab initio predictive analysis to identify putative piRNAs in PGCs. Then, we examined the expression of three repetitive sequence-linked piRNAs and 14 genic-transcript-linked piRNAs along with their linked genes using real-time PCR. All piRNAs and their linked genes were highly expressed in PGCs. Subsequently, we knocked down two known piRNA pathway genes of chicken, PIWI-like protein 1 (CIWI) and 2 (CILI), in PGCs using siRNAs. After knockdown of CIWI and CILI, we examined their effects on the expression of six putative piRNA-linked genes and DNA double-strand breakage in PGCs. The knockdown of CIWI and CILI upregulated chicken repetitive 1 (CR1) element and RAP2B, a member of RAS oncogene family, and increased DNA double-strand breakage in PGCs. CONCLUSIONS: Our results increase the understanding of PGC-expressed piRNAs and the role of piRNA pathway genes in the protection of germ cells.

The CCAAT element in the CIWI promoter regulates transcriptional initiation in chicken primordial germ cells.

The P-element-induced wimpy testis (PIWI) protein, which associates with small non-coding RNAs, is responsible for maintaining the integrity of germ cells and stem cells. Thus, transcriptional regulation of PIWI is critical for its effective functional modulation. In this study, we identified the promoter region of the PIWI homolog in chicken (CIWI), and investigated the transcriptional regulatory elements that control expression of CIWI in chicken primordial germ cells (PGCs). We constructed a vector that included the enhanced green fluorescent protein (eGFP) gene controlled by the 4-kb CIWI promoter. The vector was expressed in chicken PGCs, but not in chicken embryonic fibroblasts. Based on promoter deletion and fragmentation assays, we found that a 252-bp fragment of the CIWI promoter (-577 to -326 bp) was crucial for CIWI expression in PGCs. A CCAAT transcriptional regulatory element (-498 to -494 bp) was detected in the proximal region from the transcription initiation site of CIWI, and mutational analysis confirmed that this element regulates transcriptional initiation in chicken PGCs. Interestingly, the regions flanking the CCAAT element, which are positioned differently in HIWI (human), Miwi (mouse), and CIWI orthologs, were highly conserved. In addition, we predicted that specificity protein 1 (SP1) motifs modulate the transcriptional initiation of CIWI by binding to the 5'-flanking regions of the CCAAT box. Overall, 252 bp of the CIWI promoter possessing the transcriptional regulatory element CCAAT is crucial for regulating CIWI gene expression in chicken PGCs. This promoter may be applicable for the regulation of CIWI expression during germ-cell development.