Sulfation patterns of chondroitins in the rat brainstem during development and vestibular compensation

Session: Development: A.7.B Development of Neural Systems: Sensory Systems ; Poster presentation 4: Board no. A032 - poster no. 177

Dynamics of chondroitin sulfation in the rat brain during development and vestibular compensation

Conference Theme: Nature and Nurture in Brain FunctionsChondroitin sulfate (CS) regulates neuronal plasticity by restricting neurite growth and synapse formation. Sulfation on C- 2 of glucuronic acid, C-4 and/ or C-6 of N-acetylgalactosamine of the repeating disaccharide units contributes to the heterogeneity and functions of CS. However, the regulation of CS sulfation in the brain is still poorly understood. We hypothesized that the abundance of different sulfated CS moieties changes in coordination with plastic changes in the brain. With fluorophore-assisted carbohydrate electrophoresis, we found that in both the cortex and the brainstem during postnatal development, mono-4-sulfated chondroitin moiety increased while mono-6-sulfated moiety decreased progressively to an undetectable level in adults. Di-2, 4 and 2, 6-sulfated moieties were not detectable in early postnatal stages but small amount could be found at later stages. We set forth to find changes in CS moieties in a plastic event in adult rat. Following unilateral labyrinthectomy in adult rats, we observed immediate deficits in posture, motor and ocular functions. Time taken for functional recovery reflected compensatory rewiring of the brainstem network. During the recovery period, expression of the mono-6-sulfated chondroitin moiety resumed, reminiscent of that in the early postnatal period. Real time PCR also revealed differences in the expression of chondroitin sulfotransferases between the left and right vestibular nucleus during early stage of vestibular compensation. Taken together, the developmental changes in CS sulfation and the rise of mono-6-sulfated moiety during vestibular compensation suggest a role of CS sulfation pattern in neuronal plasticity

Change in sulfation patterns of chondroitin associated with the plastic changes in the rat brainstem

Conference Theme: Science and Aging: An Era of Discover

Assessment of Test Methods for ASR Aggregate Reactivity

The paper reports on the initial stages of a study into the use of phase analysis using typical laboratory techniques; thermogravimetric analysis (TG), infrared spectroscopy (FTIR) and x-ray diffraction (XRD) to investigate the alkali silica reaction (ASR) with a view to classifying the relative reactivity of aggregates. Phase analysis of ground aggregates reacted under AS1141.60.1 accelerated mortar bar test (AMBT) conditions in the presence of calcium hydroxide (CH) are reported for aggregates that have been identified as non-reactive, slowly-reactive and reactive according to the AMBT test. Results of the phase analysis correlated the AMBT classifications. The reactivity of the aggregates was also compared to the reactivity of a quartz flour of similar particle size distribution which was found to be less reactive than the reactive and slowly reactive aggregates. The reactivity of the quartz flour and the reactive and slowly reactive aggregate was attributed to the highly reactive conditions used

20(S)-Protopanaxadiol, a metabolite of ginsenosides, induced cell apoptosis through endoplasmic reticulum stress in human hepatocarcinoma HepG2 cells

20(S)-Protopanaxadiol (PPD), a metabolite of ginsenosides, has been demonstrated to possess cytotoxic effects on several cancer cell lines. The molecular mechanism is, however, not well understood. In this study, we have shown that PPD inhibits cell growth and induces apoptosis in human hepatocarcinoma HepG2 cells. PPD-treated cells showed a massive cytoplasmic vacuolization and a dramatic change of endoplasmic reticulum (ER) morphology. The induction of ER stress is associated with the upregulation of ER stress-associated genes and proteins. PPD activates the unfolded protein response (UPR) through the phosphorylation of PERK and eIF2α, the splicing of XBP1 mRNA, and the cleavage of AFT6. PPD also induces the intrinsic and extrinsic apoptotic pathways. It activates DR5, caspase-8, -9, -3, and promotes the cleavage of PARP while it downregulates Bcl-2, Bcl-x L and mitochondrial membrane potential. Knockdown of one of the three UPR limbs by specific siRNAs did not affect PPD-induced apoptosis, which was however, significantly suppressed by the downregulation of CHOP. Western blot analysis showed that PPD-stimulated downregulation of Bcl-2 protein, increase of DR5 protein, activation of caspase-8 and cleavage of PARP were significantly inhibited in CHOP siRNA-transfected cells. Taken together, we have identified ER as a molecular target of PPD and our data support the hypothesis that PPD induces HepG2 cell apoptosis through the ER stress pathway. © 2011 Elsevier B.V.link_to_subscribed_fulltex

Corilagin is a potent inhibitor of NF-kappaB activity and downregulates TNF-alpha induced expression of IL-8 gene in cystic fibrosis IB3-1 cells

Corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), a gallotannin identified in several plants, including Phyllanthus urinaria, has been shown to exhibit versatile medicinal activities. As far as possible anti-inflammatory effects of corilagin, only few reports are available, and the potential use of corilagin as possible therapeutic molecule for cystic fibrosis has not been evaluated. In the present paper we report experiments aimed at determining the activity of corilagin on nuclear factor kappaB (NF-kappaB) binding to DNA target and on the expression of the major pro-inflammatory gene involved in cystic fibrosis, interleukin-8 (IL-8). Both IL-8 mRNA content and IL-8 protein secretion were analyzed in cystic fibrosis bronchial IB3-1 cells stimulated by tumor necrosis factor-alpha (TNF-alpha), one of the most potent pro-inflammatory agents. The data obtained demonstrate that corilagin binds to NF-kappaB, inhibits NF-kappaB/DNA interactions and affects IL-8 gene expression in TNF-alpha treated IB3-1 cells. In addition, corilagin inhibits TNF-alpha induced secretion of MCP-1 and RANTES, exhibiting low or no effect on the release of G-CSF, IL-6 and VEGF. Therefore, corilagin might be of interest for experimental anti-inflammatory therapy of cystic fibrosis

Rechallenge with temozolomide in patients with recurrent gliomas

Temozolomide (TMZ) is the standard of care for patients with newly diagnosed glioblastoma (GBM) as well as those with recurrent anaplastic glioma (AG) and GBM. It has become common practice to re-expose patients to TMZ who had been previously treated with TMZ, or to switch patients to alternative dosing regimens of TMZ when there are signs of relapse or progress on standard TMZ therapeutic regimens. To date, however, there is a scarcity of data on the efficacy of this therapeutic strategy, currently referred to as TMZ rechallenge. We have conducted a retrospective review of patients with recurrent glioma rechallenged with TMZ. Patients experiencing progressive disease (PD) during TMZ therapy who were rechallenged with alternative TMZ regimens and patients rechallenged after stable disease in a TMZ-free interval were evaluated separately. A total of 90 rechallenges were identified in 80 patients. The progression-free survival at 6 months (PFS-6) was 48% in patients with AG (12/25) and 27.7% in those with GBM (14/47). The PFS-6 was 16.7% in AG and 26.3% in GBM for patients switched during TMZ and 57.9 and 28.6% in patients rechallenged after a TMZ-free interval of at least 8 weeks. Relevant hematological toxicity (NCI-CTC grade 3-5) was observed in 22 of 90 rechallenges, and relevant non-hematological in ten of 90 rechallenges. Temozolomide was well tolerated and generated promising PFS-6 in patients who had previously failed TMZ, regardless if they progressed during TMZ treatment, or if they were rechallenged after a TMZ-free interval. These results suggest that the TMZ rechallenge strategy warrants further investigation in a prospective randomized trial