Inhibitory effects of lactoferrin on pulmonary inflammatory processes induced by lipopolysaccharide by modulating the TLR4-related pathway.

This study tested the ability of lactoferrin to modulate pulmonary inflammation. To construct in vitro and in vivo inflammatory lung models, cells from the human lung adenocarcinoma cell line (A549) were exposed to lipopolysaccharide (LPS, 1 µg/mL), and mice (CD-1) were intratracheally administered LPS [10 mg/kg of body weight (BW), tracheal lumen injection], respectively. The A549 cells were preincubated with lactoferrin (10 mg/mL), and the mice were intraperitoneally injected with lactoferrin (100 mg/kg of BW), followed by LPS treatment. The concentrations of proinflammatory cytokines (IL-1ß and TNF-α) in culture medium of A549 cells and in bronchoalveolar lavage fluid of the mice were determined using enzyme-linked immunosorbent assays. The toll-like receptor 4-related pathway (TLR4/MyD88/IRAK1/TRAF6/NFκB) was determined at gene and protein expression levels in A549 cells and mouse lung tissue. Results showed that LPS treatment significantly elevated the concentrations of IL-1ß and TNF-α in the A549 cell culture medium and in bronchoalveolar lavage fluid of the mice; it also elevated both the mRNA and protein expressions of TLR4 and the TLR4 downstream factors in A549 cells and mouse lung tissue. Nevertheless, lactoferrin apparently depressed the releases of IL-1ß and TNF-α from A549 cells and lung tissues stimulated by LPS, and significantly suppressed the TLR4 signaling pathway. Lactoferrin also promoted the enhancement of miR-146a expression in A549 cells and mouse lung tissue. Moreover, 100°C heating for 3 min caused total loss of the previously listed bioactivity of lactoferrin. Collectively, we proved that lactoferrin intervened in LPS-induced inflammation in the pulmonary cell model and in the mouse model, through inhibiting the TLR4-related pathway.

STAT1-induced upregulation of lncRNA LINP1 promotes cell proliferation and inhibits apoptosis via AMPK signaling pathway in papillary thyroid cancer.

OBJECTIVE: The purpose of this study was to detect the relative expression of long non-coding ribonucleic acid (lncRNA) in non-homologous end joining pathway 1 (LINP1) in papillary thyroid cancer (PTC) tissues and cells, and to investigate the molecular mechanisms of abnormal expression and biological function of LINP1. PATIENTS AND METHODS: The relative expression of LINP1 in PTC tissues and cells was detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR), and the impact of small interfering (si)-LINP1 on the proliferative capacity of PTC cells was studied using Cell Counting Kit-8 (CCK-8) and colony formation assays. After the expression of LINP1 in PTC cells was interfered, flow cytometry was applied to determine the changes in cell cycle distribution and apoptosis rate. The transcription factors binding to the promoter region of LINP1 were predicted by bioinformatics. Next, qRT-PCR assay was adopted to measure the changes in LINP1 expression after interference in the expression of signal transducer and activator of transcription 1 (STAT1). Finally, the changes in the expressions of molecular markers of the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway were examined via Western blotting assay after the expressions of STAT1 and LINP1 were interfered. RESULTS: It was shown in qRT-PCR results that LINP1 expression was upregulated in 42 out of 53 cases of PTC tissues and in all PTC cells. After interference in the expression of LINP1 in PTC cells, the results of CCK-8 and colony formation assays indicated that the proliferative capacity of the cells was repressed. According to the results of flow cytometry, the cell cycle was arrested at the G1/G0 phase, and the apoptosis rate was increased. In addition, the bioinformatics predicted that STAT1 could bind to the promoter region of LINP1, and the results of qRT-PCR indicated that the expression of LINP1 declined after STAT1 expression was interfered. Moreover, it was indicated in the Western blotting assay after interference in the expressions of STAT1 and LINP1 that the expression of molecular marker (Phosphorylation AMPK, p-AMPK) of the AMPK signaling pathway was altered but the expression of total AMPK did not change. CONCLUSIONS: The transcription factor STAT1 promotes the expression of LINP1 in PTC, and highly expressed LINP1 facilitates the proliferation and inhibits the apoptosis of PTC by suppressing the AMPK signaling pathway.

Fabrication of silver tips for scanning tunneling microscope induced luminescence.

We describe a reliable fabrication procedure of silver tips for scanning tunneling microscope (STM) induced luminescence experiments. The tip was first etched electrochemically to yield a sharp cone shape using selected electrolyte solutions and then sputter cleaned in ultrahigh vacuum to remove surface oxidation. The tip status, in particular the tip induced plasmon mode and its emission intensity, can be further tuned through field emission and voltage pulse. The quality of silver tips thus fabricated not only offers atomically resolved STM imaging, but more importantly, also allows us to perform challenging "color" photon mapping with emission spectra taken at each pixel simultaneously during the STM scan under relatively small tunnel currents and relatively short exposure time.

C1 inhibitor gene sequence facilitates frameshift mutations.

Mutations disrupting the function or production of C1 inhibitor cause the disease hereditary angioneurotic edema. Patient mutations identified an imperfect inverted repeat sequence that was postulated to play a mechanistic role in the mutations. To test this hypothesis, the inverted repeat was cloned into the chloramphenicol acetyltransferase gene in pBR325 and its mutation rate was studied in four bacterial strains. These strains were selected to assay the effects of recombination and superhelical tension on mutation frequency. Mutations that revert bacteria to chloramphenicol resistance (Cmr) were scored. Both pairs of isogenic strains had reversion frequencies of approximately 10(-8). These rare reversion events in bacteria were most often a frameshift that involved the imperfect inverted repeat with a deletion or a tandem duplication, an event very similar to the human mutations. Increased DNA superhelical tension, which would be expected to enhance cruciform extrusion, did not accentuate mutagenesis. This finding suggests that the imperfect inverted repeat may form a stem-loop structure in the single-stranded DNA created by the duplex DNA melting prior to replication. Models explaining the slippage can be drawn using the lagging strand of the replication fork. In this model, the formation of a stem-loop structure is responsible for bringing the end of the deletion or duplication into close proximity.