Decreased syntaxin17 expression contributes to the pathogenesis of acute pancreatitis in murine models by impairing autophagic degradation.

Acute pancreatitis (AP) is an inflammatory disease of the exocrine pancreas. Disruptions in organelle homeostasis, including macroautophagy/autophagy dysfunction and endoplasmic reticulum (ER) stress, have been implicated in human and rodent pancreatitis. Syntaxin 17 (STX17) belongs to the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) subfamily. The Qa-SNARE STX17 is an autophagosomal SNARE protein that interacts with SNAP29 (Qbc-SNARE) and the lysosomal SNARE VAMP8 (R-SNARE) to drive autophagosome-lysosome fusion. In this study, we investigated the role of STX17 in the pathogenesis of AP in male mice or rats induced by repeated intraperitoneal injections of cerulein. We showed that cerulein hyperstimulation induced AP in mouse and rat models, which was characterized by increased serum amylase and lipase activities, pancreatic edema, necrotic cell death and the infiltration of inflammatory cells, as well as markedly decreased pancreatic STX17 expression. A similar reduction in STX17 levels was observed in primary and AR42J pancreatic acinar cells treated with CCK (100 nM) in vitro. By analyzing autophagic flux, we found that the decrease in STX17 blocked autophagosome-lysosome fusion and autophagic degradation, as well as the activation of ER stress. Pancreas-specific STX17 knockdown using adenovirus-shSTX17 further exacerbated pancreatic edema, inflammatory cell infiltration and necrotic cell death after cerulein injection. These data demonstrate a critical role of STX17 in maintaining pancreatic homeostasis and provide new evidence that autophagy serves as a protective mechanism against AP.

Salvianolic acid B suppresses hepatic fibrosis by inhibiting ceramide glucosyltransferase in hepatic stellate cells.

UDP-glucose ceramide glucosyltransferase (UGCG) is the first key enzyme in glycosphingolipid (GSL) metabolism that produces glucosylceramide (GlcCer). Increased UGCG synthesis is associated with cell proliferation, invasion and multidrug resistance in human cancers. In this study we investigated the role of UGCG in the pathogenesis of hepatic fibrosis. We first found that UGCG was over-expressed in fibrotic livers and activated hepatic stellate cells (HSCs). In human HSC-LX2 cells, inhibition of UGCG with PDMP or knockdown of UGCG suppressed the expression of the biomarkers of HSC activation (α-SMA and collagen I). Furthermore, pretreatment with PDMP (40 µM) impaired lysosomal homeostasis and blocked the process of autophagy, leading to activation of retinoic acid signaling pathway and accumulation of lipid droplets. After exploring the structure and key catalytic residues of UGCG in the activation of HSCs, we conducted virtual screening, molecular interaction and molecular docking experiments, and demonstrated salvianolic acid B (SAB) from the traditional Chinese medicine Salvia miltiorrhiza as an UGCG inhibitor with an IC50 value of 159 µM. In CCl4-induced mouse liver fibrosis, intraperitoneal administration of SAB (30 mg · kg-1 · d-1, for 4 weeks) significantly alleviated hepatic fibrogenesis by inhibiting the activation of HSCs and collagen deposition. In addition, SAB displayed better anti-inflammatory effects in CCl4-induced liver fibrosis. These results suggest that UGCG may represent a therapeutic target for liver fibrosis; SAB could act as an inhibitor of UGCG, which is expected to be a candidate drug for the treatment of liver fibrosis.

Potential of herb-drug / herb interactions between substrates and inhibitors of UGTs derived from herbal medicines.

Herbal medicines are widely used as alternative or complementary therapies worldwide to treat and prevent chronic diseases. However, herbal medicines coadministration with therapeutic drugs may cause dramatic clinical herb-drug/herb interactions (HDIs/HHIs) that may result in low drug efficacy or serious toxic reactions. Phase II metabolism enzyme UDP-glucuronosyltransferases (UGTs) play a significant detoxification role in vivo. Most drugs and non-drug xenobiotics undergo phase II metabolic transformations to be more polar compounds that are more easily excreted. Herbal medicines are a mixed and chemically varied group that includes flavonoids, stilbenes, coumarins, quinones, and terpenes, which are potential substrates and inhibitors of UGTs. Although increasing studies about glucuronidation metabolism and the inhibition toward UGTs of many herbal medicines have been reported, it is still difficult to determine which compounds from herbal medicines are substrates or inhibitors of UGTs. This article gives an overview of UGTs studies, which mainly focuses on glucuronidation of herbal constituents as substrates catalyzed by UGTs, potential herbal inhibitors for UGTs. We summarize the negative effects of UGT1A polymorphism and single nucleotide polymorphisms (SNPs), relevant clinical situations of HDIs/HHIs induced by inhibition of UGTs, and propose establishing classification criteria for inhibitors. Finally, we also discuss future research and strategic directions to advance the understanding of the potential HDIs/HHIs and suggest some additional studies revealing more information on UGT-mediated HDIs/HHIs.

[Effects of taking estrogen and progestogen after medical abortion on reducing vaginal hemorrhage time: a randomized-controlled trial].

OBJECTIVE: To compare the different effects of taking different kinds and doses of estrogen and progestogen after medical abortion on reducing vaginal hemorrhage time. METHODS: A total of 188 women undergoing medical abortion were recruited and randomized into 3 groups: group A (n = 41) starting marvelon (30 µg ethinylestradiol and 150 µg desogestrel) on the day of abortion for 21 days; group B (n = 53) starting progynova 2 mg/d on the day of abortion for 21 days and taking depogesterone 10 mg/d on the last 5 days; and group C (n = 94) as control. The vaginal hemorrhage time, days to onset of next menses and the outcome of medical abortion were compared. RESULTS: There was no significant difference in the duration of hemorrhage between groups A and C [(20 ± 13) vs (19 ± 11) d, P > 0.05]. But the duration of hemorrhage in group B was significantly shorter than that in group C [(14 ± 7) vs (19 ± 11) d, P < 0.01]. There was no significant difference in the amount of hemorrhage among 3 groups (P > 0.05). The time to onset of first menses was similar between groups A and B [(34 ± 13) vs (30 ± 7) d]. And both were significantly shorter than that in group C [(39 ± 11) d, P < 0.05]. There were 3 (7.32%) incomplete abortions in group A, 4 (7.55%) in group B and 12 (12.77%) in group C (P > 0.05). CONCLUSION: The sequential therapy of estrogen and progestogen after medical abortion may effectively reduce the duration of hemorrhage. And the combined oral contraceptive pills fail to significantly alter the duration of hemorrhage after medical abortion. But both can promote menstrual recovery significantly.