Increased expression of glial fibrillary acidic protein (GFAP) represents astroglial activation and gliosis during neurodegeneration. However, the molecular mechanism behind increased expression of GFAP in astrocytes is poorly understood. The present study was undertaken to explore the role of nitric oxide (

Increased expression of CD11b, the ␤-integrin marker of microglia, represents microglial activation during neurodegenerative inflammation. However, the molecular mechanism behind increased microglial CD11b expression is poorly understood. The present study was undertaken to explore the role of nitric oxide (

It has been shown that peptides corresponding to the NF-κB essential modifier-binding domain (NBD) of IκB kinase α or IκB kinase β specifically inhibit the induction of NF-κB activation without inhibiting the basal NF-κB activity. The present study demonstrates the effectiveness of NBD peptides in inhibiting the disease process in adoptively transferred experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis. Clinical symptoms of EAE were much lower in mice receiving wild-type (wt)NBD peptides compared with those receiving mutated (m)NBD peptides. Histological and immunocytochemical analysis showed that wtNBD peptides inhibited EAE-induced spinal cord mononuclear cell invasion and normalized p65 (the RelA subunit of NF-κB) expression within the spinal cord. Analysis of lymph node cells isolated from donor and recipient mice showed that wtNBD peptides but not mNBD peptides were able to shift the immune response from a Th1 to a Th2 profile. Consistently, wtNBD peptides but not mNBD peptides inhibited the encephalitogenicity of myelin basic protein-specific T cells. Furthermore, i.p. injection of wtNBD peptides but not mNBD peptides was also able to reduce LPS- and IFN-γ-induced expression of inducible NO synthase, IL-1β, and TNF-α in vivo in the cerebellum. Taken together, our results support the conclusion that NBD peptides are antineuroinflammatory, and that NBD peptides may have therapeutic effect in neuroinflammatory disorders such as multiple sclerosis.

Microglial activation is considered as a hallmark of several neurodegenerative disorders. During microglial activation, the expression of CD11b, the beta-integrin marker of microglia, is increased. However, the molecular mechanism behind increased microglial CD11b expression is poorly understood. The present study was undertaken to explore the role of reactive oxygen species (ROS) in the expression of CD11b in microglial cells. Bacterial lipopolysaccharide (LPS) stimulated the expression of CD11b in mouse BV-2 microglial cells and primary microglia, the effect that was blocked by antioxidants such as N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC). Furthermore, comicroinjection of either NAC or PDTC with LPS was also able to suppress LPSstimulated expression of CD11b in striatum in vivo. Similarly, other neurotoxic molecules, such as interleukin-1β (IL-1β), IL-12 p40 2 , fibrillar amyloid-β (Aβ) peptides, HIV-1 gp120, and doublestranded RNA (poly(IC)), also stimulated the expression of CD11b in microglia through the involvement of ROS. Complete inhibition of LPS-stimulated expression of CD11b by catalase, induction of CD11b expression by H 2 O 2 alone, and inhibition of superoxide-stimulated CD11b expression by catalase suggest that H 2 O 2 , but not superoxide, is in fact involved in the expression of CD11b. Interestingly, we also demonstrate that ROS stimulated the expression of CD11b after the induction of nitric oxide (NO) production and failed to stimulate CD11b when NO production was inhibited by either 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) or L-N6-(1-iminoethyl)-L-lysine (L-NIL). Taken together, these studies suggest that the upregulation of CD11b in microglia is redox sensitive and that ROS up-regulates CD11b via NO.

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Despite being a proinflammatory cytokine, tumor necrosis factor-α (TNF-α) preconditions neurons against various toxic insults. However, underlying molecular mechanisms are poorly understood. The present study identifies the importance of CREB-binding protein (CBP) in facilitating TNF-α-mediated preconditioning in neurons. Treatment of rat primary neurons with fibrillar amyloid-β 1–42 (Aβ) resulted in the loss of CBP protein. However, this loss was compensated by TNF-α preconditioning as the expression of neuronal CBP was upregulated in response to TNF-α treatment. The induction of CBP by TNF-α was observed only in neurons, but not in astroglia and microglia, and it was contingent on the activation of transcription factor NF-κB. Interestingly, antisense knockdown of CBP abrogated TNF-α-mediated preconditioning of neurons against Aβ and glutamate toxicity. Similarly in vivo, pre-administration of TNF-α in mouse cortex prevented Aβ-induced apoptosis and loss of choline acetyl transferase (ChAT)-positive cholinergic neurons. However, co-administration of cbp antisense, but not scrambled oligonucleotides, negated the protective effect of TNF-α against Aβ neurotoxicity. This study illustrates a novel biological role of TNF-α in increasing neuron-specific expression of CBP for preconditioning that may have therapeutic potential against neurodegenerative disorders.

Limited research in young adults and immature animals suggests a detrimental effect of tobacco on bone during growth. This study investigated the effects of nicotine, the major alkaloid component of tobacco, on calciotropic hormone concentrations and bone status in growing female rats. One-month-old animals received either saline (n = 10), nicotine at 3.0 mg/kg/day (n = 10), or nicotine at 4.5 mg/kg/day (n = 10) administered subcutaneously via osmotic minipumps for either 2 or 3 months. Sera, femora, tibiae, and lumbar vertebrae (3-5) were collected at necropsy. The concentrations of serum calcium, phosphorus, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroid hormone, calcitonin, and insulin-like growth factor-I were determined. Bone variables evaluated included mineral content and density (vertebrae and femora), cancellous and cortical histomorphometry (tibiae), and bone strength (vertebrae and femora). Statistically significant differences in serum mineral and hormone concentrations were not associated with nicotine dose or exposure time. No significant nicotine treatment effects were detected for bone mineral content and density, bone histomorphometry, or bone strength. We conclude that nicotine treatment for 2 or 3 months at serum concentrations in the upper range of those found in smokers has no detrimental effect on bone mass, volume, or strength in the growing rat.

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