Extraction of antibacterial peptides against Helicobacter pylori from bovine milk casein.

Introduction: More than half of the world's population is infected with Helicobacter pylori, which may cause gastritis, peptic ulcer and even gastric cancer. The World Health Organization (WHO) has announced that H. pylori infection is a class I carcinogen and hence eradication of it is highly important. Bovine milk contains caseins, which can be digested by various enzymes in the human stomach to produce antibacterial peptides. Material and methods: This study used in vitro methods to extract anti-H. pylori peptides from caseins by the gastric protease pepsin under environments with similar pH values to those found in the human stomach. The molecular weights and sequences of the peptides were identified by MALDI-TOF mass spectrometry and MS/MS Ion Search, respectively. Antibacterial activity tests were performed to calculate the minimum inhibitory concentration (MIC90) of the extracts. Results: The findings of this study revealed that the major products of bovine milk casein digestion by pepsin are casecidin 17 and ß-casein 207-224. The extracts produced promising anti-H. pylori effects with the lowest MIC90 found at pH values of 1.5 and 2.0. Conclusions: This study identified the anti-H. pylori effects of casecidin 17 and ß-casein 207-224, which may help in developing therapeutic agents to modulate the effect of antibiotics on H. pylori infections.

Architecture of Dispatched, a Transmembrane Protein Responsible for Hedgehog Release.

The evolutionarily conserved Hedgehog (Hh) signaling pathway is crucial for programmed cell differentiation and proliferation. Dispatched (Disp) is a 12-transmembrane protein that plays a critical role in the Hedgehog (Hh) signaling pathway by releasing the dually lipidated ligand HhN from the membrane, a prerequisite step to the downstream signaling cascade. In this study, we focus on the Disp from water bear, a primitive animal known as the most indestructible on Earth. Using a zebrafish model, we show that the water bear homolog possesses the function of Disp. We have solved its structure to a 6.5-Å resolution using single-particle cryogenic electron microscopy. Consistent with the evolutional conservation of the pathway, the water bear Disp structure is overall similar to the previously reported structures of the fruit fly and human homologs. Although not revealing much detail at this resolution, the water bear Disp shows a different conformation compared to published structures, suggesting that they represent different functional snapshots.

Cryo-EM study of patched in lipid nanodisc suggests a structural basis for its clustering in caveolae.

The 12-transmembrane protein Patched (Ptc1) acts as a suppressor for Hedgehog (Hh) signaling by depleting sterols in the cytoplasmic membrane leaflet that are required for the activation of downstream regulators. The positive modulator Hh inhibits Ptc1's transporter function by binding to Ptc1 and its co-receptors, which are locally concentrated in invaginated microdomains known as caveolae. Here, we reconstitute the mouse Ptc1 into lipid nanodiscs and determine its structure using single-particle cryoelectron microscopy. The structure is overall similar to those in amphipol and detergents but displays various conformational differences in the transmembrane region. Although most particles show monomers, we observe Ptc1 dimers with distinct interaction patterns and different membrane curvatures, some of which are reminiscent of caveolae. We find that an extramembranous "hand-shake" region rich in hydrophobic and aromatic residues mediates inter-Ptc1 interactions under different membrane curvatures. Our data provide a plausible framework for Ptc1 clustering in the highly curved caveolae.

[Role of lncRNA PTENP1 in tumorigenesis and progression of bladder cancer and the molecular mechanism].

OBJECTIVE: To explore the molecular mechanism underlying the biological function of lncRNA PTENP1 in bladder cancer. METHODS: Expressions of PTENP1, PTEN and miR-17 were examined by quantitative reverse transcriptase PCR (qRT-PCR) in 12 bladder cancer tissues. The expression of PTEN was examined by Western blotting in bladder cancer cell lines T24 and 5637 overexpressing PTENP1. Luciferase reporter assay was performed to confirm the targeting of miR-17 to PTENP1 and PTEN. T24 and 5637 cell lines with stable overexpression of PTENP1 and mir-17 were used to investigate effect of PTNE and miR-17 on the function of PTENP1 in bladder cancer. RESULTS: The expression of miR-17 was up-regulated and PTENP1 and PTEN were down-regulated in bladder cancer tissues, where a positive correlation was found between PTENP1 and PTEN expressions and a negative correlation between PTENP1 and miR-17 (P<0.05). Overexpression of PTENP1 in bladder cancer cell lines T24 and 5637 obviously enhanced the expression of PTEN protein. miR-17 was found to target both PTENP1 and PTEN and promote the growth of bladder cancer. miR-17 could partially restore the tumor-suppressing activity of PTENP1 in bladder cancer. CONCLUSION: By binding with miR-17, lncRNA PTENP1 functions as a PTEN competing endogenous RNA (ceRNA) to suppress the progression of bladder cancer.