Globoidnan A: a lignan from Eucalyptus globoidea inhibits HIV integrase

An HTS campaign aimed at the identification of inhibitors of HIV integrase showed that the methanol extract from the buds of a Eucalyptus globoidea was active. Bioassay guided fractionation of this extract resulted in the purification and structural elucidation of the lignan, globoidnan A (1) as the only compound in the extract responsible for the inhibition of HIV integrase. The compound was found to inhibit the combined 3' processing and strand transfer activity of HIV integrase with an IC50=0.64 microM.     

Acetylcholinesterase Is Increased in the Brains of Transgenic Mice Expressing the C-Terminal Fragment (CT100) of the β-Amyloid Protein Precursor of Alzheimer's Disease

Abstract: Acetylcholinesterase (AChE) expression is markedly affected in Alzheimer's disease (AD). AChE activity is lower in most regions of the AD brain, but it is increased within and around amyloid plaques. We have previously shown that AChE expression in P19 cells is increased by the amyloid β protein (Aβ). The aim of this study was to investigate AChE expression using a transgenic mouse model of Aβ overproduction. The β-actin promoter was used to drive expression of a transgene encoding the 100-amino acid C-terminal fragment of the human amyloid precursor protein (APP CT100). Analysis of extracts from transgenic mice revealed that the human sequences of full-length human APP CT100 and Aβ were overexpressed in the brain. Levels of salt-extractable AChE isoforms were increased in the brains of APP CT100 mice. There was also an increase in amphiphilic monomeric form (G^A₁) of AChE in the APP CT100 mice, whereas other isoforms were not changed. An increase in the proportion of G^A₁ AChE was also detected in samples of frontal cortex from AD patients. Analysis of AChE by lectin binding revealed differences in the glycosylation pattern in APP CT100 mice similar to those observed in frontal cortex samples from AD. The results are consistent with the possibility that changes in AChE isoform levels and glycosylation patterns in the AD brain may be a direct consequence of altered APP metabolism.     

Localisation of the Vacuolar Proton Pump (V-H+-ATPase) and Carbonic Anhydrase II in the Human Eccrine Sweat Gland

The localisation of the vacuolar proton pump (V-H+ -ATPase) and the enzyme carbonic anhydrase II (CAII) was investigated in the human eccrine sweat gland employing standard immunohistochemical techniques after antigen retrieval using microwave heat treatment and high pressure. The high-pressure antigen retrieval unmasked the presence of V-H+ -ATPase in the clear cells of the secretory coil, with a distribution similar to that previously observed for CAII. However, the dark cells were unreactive to both antibodies. In addition, heat and high-pressure antigen retrieval demonstrated the presence of CAII in the apical zone of luminal cells of the reabsorptive duct, a location not previously reported. The localisation of V-H+ -ATPase and CAII in the secretory coil clear cells suggests that the formation of HCO3- and H+ by carbonic anhydrase II and the transport of H+ by V-H+ -ATPase may play an role in sweat fluid secretion. Their presence at the apex of the duct cells indicates involvement in ductal ion reabsorption.     

Differential expression and function of breast regression protein 39 (BRP-39) in murine models of subacute cigarette smoke exposure and allergic airway inflammation

Background

While the presence of the chitinase-like molecule YKL40 has been reported in COPD and asthma, its relevance to inflammatory processes elicited by cigarette smoke and common environmental allergens, such as house dust mite (HDM), is not well understood. The objective of the current study was to assess expression and function of BRP-39, the murine equivalent of YKL40 in a murine model of cigarette smoke-induced inflammation and contrast expression and function to a model of HDM-induced allergic airway inflammation.

Methods

CD1, C57BL/6, and BALB/c mice were room air- or cigarette smoke-exposed for 4 days in a whole-body exposure system. In separate experiments, BALB/c mice were challenged with HDM extract once a day for 10 days. BRP-39 was assessed by ELISA and immunohistochemistry. IL-13, IL-1R1, IL-18, and BRP-39 knock out (KO) mice were utilized to assess the mechanism and relevance of BRP-39 in cigarette smoke- and HDM-induced airway inflammation.

Results

Cigarette smoke exposure elicited a robust induction of BRP-39 but not the catalytically active chitinase, AMCase, in lung epithelial cells and alveolar macrophages of all mouse strains tested. Both BRP-39 and AMCase were increased in lung tissue after HDM exposure. Examining smoke-exposed IL-1R1, IL-18, and IL-13 deficient mice, BRP-39 induction was found to be IL-1 and not IL-18 or IL-13 dependent, while induction of BRP-39 by HDM was independent of IL-1 and IL-13. Despite the importance of BRP-39 in cellular inflammation in HDM-induced airway inflammation, BRP-39 was found to be redundant for cigarette smoke-induced airway inflammation and the adjuvant properties of cigarette smoke.

Conclusions

These data highlight the contrast between the importance of BRP-39 in HDM- and cigarette smoke-induced inflammation. While functionally important in HDM-induced inflammation, BRP-39 is a biomarker of cigarette smoke induced inflammation which is the byproduct of an IL-1 inflammatory pathway.     

Chromosome-breakage genomic instability and chromothripsis in breast cancer

Background

Chromosomal breakage followed by faulty DNA repair leads to gene amplifications and deletions in cancers. However, the mere assessment of the extent of genomic changes, amplifications and deletions may reduce the complexity of genomic data observed by array comparative genomic hybridization (array CGH). We present here a novel approach to array CGH data analysis, which focuses on putative breakpoints responsible for rearrangements within the genome.

Results

We performed array comparative genomic hybridization in 29 primary tumors from high risk patients with breast cancer. The specimens were flow sorted according to ploidy to increase tumor cell purity prior to array CGH. We describe the number of chromosomal breaks as well as the patterns of breaks on individual chromosomes in each tumor. There were differences in chromosomal breakage patterns between the 3 clinical subtypes of breast cancers, although the highest density of breaks occurred at chromosome 17 in all subtypes, suggesting a particular proclivity of this chromosome for breaks. We also observed chromothripsis affecting various chromosomes in 41% of high risk breast cancers.

Conclusions

Our results provide a new insight into the genomic complexity of breast cancer. Genomic instability dependent on chromosomal breakage events is not stochastic, targeting some chromosomes clearly more than others. We report a much higher percentage of chromothripsis than described previously in other cancers and this suggests that massive genomic rearrangements occurring in a single catastrophic event may shape many breast cancer genomes.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-579) contains supplementary material, which is available to authorized users.