Preparation of purified proteins from fresh Pheretima and their inhibitory effect against pulmonary fibrosis in mice / 南方医科大学学报

OBJECTIVE@#To develop a convenient method for rapid purification of fresh Pheretima proteins and assess the inhibitory effect of these proteins against pulmonary fibrosis.@*METHODS@#The crude extract of fresh Pheretima was obtained by freeze-drying method and then purified by size exclusion chromatography. The composition of the purified proteins was analyzed by mass spectrometry. MRC-5 cells were treated with 5 ng/mL TGF-β1 alone (model group) or in combination with SB431542 (2 μmol/L) or the purified proteins (13.125 μg/mL), and the cytotoxicity of purified proteins and their inhibitory effects on cell proliferation were detected with CCK8 assay. Flow cytometry was used to detect the changes in cell apoptosis, and the cellular expressions of α-SMA, Vimentin, E-cadherin, collagen I, Smad2/3 and P-Smad2/3 were detected using RT-PCR and Western blotting. In the animal experiment, adult male C57BL/6 mice were subjected to intratracheal instillation of bleomycin followed by treatment with the purified proteins (5 mg/mL) for 21 days, after which HE and Masson staining was used to observe the pathological changes in the lung tissue of the mice.@*RESULTS@#We successfully obtained purified proteins from fresh Pheretima protein by size exclusion chromatography. Treatment with the purified proteins significantly inhibited TGF-β1-induced proliferation of MRC-5 cells (P < 0.01), reduced the cellular expressions of α-SMA, Vimentin and collagen I (P < 0.001 or P < 0.01), increased the expression of E-cadherin (P < 0.01), and inhibited the expressions of Smad2/3 and P-Smad2/3 (P < 0.001 or P < 0.01). In male C57BL/6 mice models of bleomycin-induced pulmonary fibrosis, treatment with the purified proteins obviously reduced the number of inflammatory cells and fibrotic area in the lungs.@*CONCLUSION@#The purified proteins from fresh Pheretima obtained by size exclusion chromatography can inhibit pulmonary fibrosis in mice by regulating the TGF-β/ Smad pathway.

LINGO-1 antibody ameliorates myelin impairment and spatial memory deficits in the early stage of 5XFAD mice.

AIMS: Multiple evidence has indicated that myelin injury is common in Alzheimer's disease (AD). However, whether myelin injury is an early event in AD and the relationship between it and cognitive function is still elusive. METHODS: Spatial memory of 5XFAD mice was determined by Morris water maze at 1 and 3 months old. Meanwhile, the deposition of Aß, the expression of myelin basic protein (MBP), LINGO-1, NgR, and myelin ultrastructure in many memory-associated brain regions were detected in one-month-old and three-month-old mice (before and after LINGO-1 antibody administration) using immunostaining, Western blot (WB), and transmission electron microscopy (TEM), respectively. RESULTS: No abnormal Aß deposition was found in one-month-old 5XFAD mice. However, spatial memory deficits were proved in accordance with an obvious demyelination in memory-associated brain regions in one-month-old mice and both deteriorated with age. Administration of LINGO-1 antibody could obviously restore the myelin impairments in CA1 and DG region and partially ameliorate spatial memory deficits. CONCLUSIONS: Our results demonstrated that myelin injury was an early event in 5XFAD mice even prior to emergence of deposition of Aß. Intervention with the LINGO-1 antibody could attenuate impaired spatial memory deficits by remyelination, which suggested that myelin injury was involved in spatial memory deficits and remyelination may be a potential therapeutic strategy in early stage of AD or mild cognitive impairments.

Spatial learning and memory impairments are associated with increased neuronal activity in 5XFAD mouse as measured by manganese-enhanced magnetic resonance imaging.

Dysfunction of neuronal activity is a major and early contributor to cognitive impairment in Alzheimer's disease (AD). To investigate neuronal activity alterations at early stage of AD, we encompassed behavioral testing and in vivo manganese-enhanced magnetic resonance imaging (MEMRI) in 5XFAD mice at early ages (1-, 2-, 3- and 5-month). The 5XFAD model over-express human amyloid precursor protein (APP) and presenilin 1 (PS1) harboring five familial AD mutations, which have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-ß. In the Morris water maze, 5XFAD mice showed longer escape latency and poorer memory retention. In the MEMRI, 5XFAD mice showed increased signal intensity in the brain regions involved in spatial cognition, including the entorhinal cortex, the hippocampus, the retrosplenial cortex and the caudate putamen. Of note, the observed alterations in spatial cognition were associated with increased MEMRI signal intensity. These findings indicate that aberrant increased basal neuronal activity may contribute to the spatial cognitive function impairment at early stage of AD, and may further suggest the potential use of MEMRI to predict cognitive impairments. Early intervention that targets aberrant neuronal activity may be crucial to prevent cognitive impairment.

Potent in vitro interference of fleroxacin in DNA-binding, unwinding and ATPase activities of Bloom helicase / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of fleroxacin (FLRX) on biological properties of Bloom (BLM) helicase catalytic core (BLM642-1290 helicase) in vitro and the molecular mechanism of interaction between the two molecules.</p><p><b>METHODS</b>DNA-binding and unwinding activities of BLM642-1290 helicase were assayed by fluorescence polarization and gel retardation assay under conditions that the helicase was subjected to different concentrations of FLRX. Effect of FLRX on helicase ATPase activity was analyzed by phosphorus-free assay based on a colorimetric estimation of ATP hydrolysis-produced inorganic phosphate. Molecular mechanism of interaction between the two molecules was assayed by ultraviolet and fluorescence spectra.</p><p><b>RESULTS</b>The DNA unwinding and ATPase activities of BLM642-1290 helicase were inhibited whereas the DNA-binding activity was promoted in vitro. A BLM-FLRX complex was formed through one binding site, electrostatic and hydrophobic interaction force. Moreover, the intrinsic fluorescence of the helicase was quenched by FLRX as a result of non-radioactive energy transfer. The biological activity of helicase was affected by FLRX, which may be through an allosteric mechanism and stabilization of enzyme conformation in low helicase activity state, disruption of the coupling of ATP hydrolysis to unwinding, and blocking helicase translocation on DNA strands.</p><p><b>CONCLUSION</b>FLRX may affect the biological activities and conformation of BLM642-1290 helicase, and DNA helicase may be used as a promising drug target for some diseases.</p>