The small molecule CA140 inhibits the neuroinflammatory response in wild-type mice and a mouse model of AD.

BACKGROUND: Neuroinflammation is associated with neurodegenerative diseases, including Alzheimer's disease (AD). Thus, modulating the neuroinflammatory response represents a potential therapeutic strategy for treating neurodegenerative diseases. Several recent studies have shown that dopamine (DA) and its receptors are expressed in immune cells and are involved in the neuroinflammatory response. Thus, we recently developed and synthesized a non-self-polymerizing analog of DA (CA140) and examined the effect of CA140 on neuroinflammation. METHODS: To determine the effects of CA140 on the neuroinflammatory response, BV2 microglial cells were pretreated with lipopolysaccharide (LPS, 1 µg/mL), followed by treatment with CA140 (10 µM) and analysis by reverse transcription-polymerase chain reaction (RT-PCR). To examine whether CA140 alters the neuroinflammatory response in vivo, wild-type mice were injected with both LPS (10 mg/kg, intraperitoneally (i.p.)) and CA140 (30 mg/kg, i.p.), and immunohistochemistry was performed. In addition, familial AD (5xFAD) mice were injected with CA140 or vehicle daily for 2 weeks and examined for microglial and astrocyte activation. RESULTS: Pre- or post-treatment with CA140 differentially regulated proinflammatory responses in LPS-stimulated microglia and astrocytes. Interestingly, CA140 regulated D1R levels to alter LPS-induced proinflammatory responses. CA140 significantly downregulated LPS-induced phosphorylation of ERK and STAT3 in BV2 microglia cells. In addition, CA140-injected wild-type mice exhibited significantly decreased LPS-induced microglial and astrocyte activation. Moreover, CA140-injected 5xFAD mice exhibited significantly reduced microglial and astrocyte activation. CONCLUSIONS: CA140 may be beneficial for preventing and treating neuroinflammatory-related diseases, including AD.

Assay to screen for molecules that associate with Alzheimer's related beta-amyloid fibrils.

Small molecules that bind to aggregated forms of Abeta peptides show promise as potential in vivo labeling agents for the diagnosis and monitoring of Alzheimer's disease. A major challenge in developing potential imaging agents that target Abeta is to rapidly identify and evaluate the association of molecules with insoluble deposits of aggregated Abeta peptides. This paper describes a simple, parallel method to rapidly screen libraries of molecules for their ability to associate with fibrils formed from synthetic Abeta peptides by monitoring their ability to inhibit the interaction of a monoclonal anti-Abeta IgG with these fibrils. We demonstrate that this assay can detect the association of small molecules with Abeta fibrils at concentrations of small molecule in the nanomolar to millimolar range. By comparing results from the screening of a small set of 30 compounds, we illustrated that this assay can rapidly analyze the relative affinity of small molecules for Abeta fibrils and identified eight compounds that can bind to Abeta fibrils at <20 microM concentrations. Significant advantages of this assay are (1) the ability to screen structurally diverse molecules without requiring them to have specific spectroscopic or radiolabeled properties, (2) the ability to estimate the percentage of the surface of the fibrils covered by the small molecules, and (3) the ability to detect the association of small molecules that potentially bind to different sites along the fibril axis. This assay also has minimal requirements for equipment or specialized facilities and should, therefore, be useful for both academic and industrial laboratories.

Amyloid-beta-induced ion flux in artificial lipid bilayers and neuronal cells: resolving a controversy.

Understanding the pathogenicity of amyloid-beta (Abeta) peptides constitutes a major goal in research on Alzheimer's disease (AD). One hypothesis entails that Abeta peptides induce uncontrolled, neurotoxic ion flux through cellular membranes. The exact biophysical mechanism of this ion flux is, however, a subject of an ongoing controversy which has attenuated progress toward understanding the importance of Abeta-induced ion flux in AD. The work presented here addresses two prevalent controversies regarding the nature of transmembrane ion flux induced by Alphabeta peptides. First, the results clarify that Alphabeta can induce stepwise ion flux across planar lipid bilayers as opposed to a gradual increase in transmembrane current; they show that the previously reported gradual thinning of membranes with concomitant increase in transmembrane current arises from residues of the solvent hexafluoroisopropanol, which is commonly used for the preparation of amyloid samples. Second, the results provide additional evidence suggesting that Abeta peptides can induce ion channel-like ion flux in cellular membranes that is independent from the postulated ability of Alphabeta to modulate intrinsic cellular ion channels or transporter proteins.