Effects and mechanism of aromatic aminoketone SY0916 on osteoclastic bone destruction

Degradation Characteristics of a Novel PAF Receptor Antagonist, SY0916, in Aqueous Solution

SY0916 has been proven to be a potent treatment agent against rheumatoid arthritis in preclinical studies and has been shown to be safe in phase I clinical trials. However, SY0916 is unstable in water, which is frequently used in pharmaceutical development processes. The degradation behaviour and stability of SY0916 in aqueous solutions were investigated at different pH levels, periods of time, and temperatures. Two degradation products (DPs) were successfully separated and characterized by liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS), liquid chromatography coupled to nuclear magnetic resonance with solid phase extraction (LC-SPE-NMR), and nuclear magnetic resonance (NMR). SY0916 decomposed to its α,β-unsaturated ketone in protonic solvents, and the α,β-unsaturated ketone further transformed into its alcohol form through a conjugate addition reaction in aqueous media. The results of this study indicate that the pH of the buffer solutions should be maintained between 3.0 and 3.6 for maximum SY0916 stability. Factors that affect degradation should be carefully controlled to mitigate or avoid drug decay.

Free-floating adult human brain-derived slice cultures as a model to study the neuronal impact of Alzheimer's disease-associated Aβ oligomers

BACKGROUND

Slice cultures have been prepared from several organs. With respect to the brain, advantages of slice cultures over dissociated cell cultures include maintenance of the cytoarchitecture and neuronal connectivity. Slice cultures from adult human brain have been reported and constitute a promising method to study neurological diseases. Despite this potential, few studies have characterized in detail cell survival and function along time in short-term, free-floating cultures.

NEW METHOD

We used tissue from adult human brain cortex from patients undergoing temporal lobectomy to prepare 200 μm-thick slices. Along the period in culture, we evaluated neuronal survival, histological modifications, and neurotransmitter release. The toxicity of Alzheimer's-associated Aβ oligomers (AβOs) to cultured slices was also analyzed.

RESULTS

Neurons in human brain slices remain viable and neurochemically active for at least four days in vitro, which allowed detection of binding of AβOs. We further found that slices exposed to AβOs presented elevated levels of hyperphosphorylated Tau, a hallmark of Alzheimer's disease.

COMPARISON WITH EXISTING METHOD(S)

Although slice cultures from adult human brain have been previously prepared, this is the first report to analyze cell viability and neuronal activity in short-term free-floating cultures as a function of days in vitro.

CONCLUSIONS

Once surgical tissue is available, the current protocol is easy to perform and produces functional slices from adult human brain. These slice cultures may represent a preferred model for translational studies of neurodegenerative disorders when long term culturing in not required, as in investigations on AβO neurotoxicity.

The antinociceptive effect and mechanism of action of SY0916

Pain greatly affects the quality of life of people worldwide. Despite their demonstrated efficacy, currently used opioid drugs and nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently associated with several adverse events. The identification of new therapeutic targets and the development of corresponding analgesics may represent novel approaches for effectively treating pain. SY0916 is a novel compound that was designed and synthesized by the Institute of Materia Medica, Chinese Academy of Medical Sciences. As demonstrated by the hot plate test, tail-flick test and the formalin test, SY0916 exerted strong peripheral and central antinociceptive effects. Western blot, immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) results indicate that SY0916 induces its peripheral antinociceptive effect by suppressing the peripheral activity of inflammatory mediators such as prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α) and 5-hydroxytryptamine (5-HT). Moreover, its central antinociceptive effect might be mediated by the down-regulation of PGE2 and TNF-α expression and the inhibition of p-p38 and NF-κB pathway signaling in glial cells. These findings demonstrate that SY0916 may serve as a promising analgesic candidate drug.