RT Journal Article
SR Electronic
T1 Noradrenergic Depletion Potentiates β-Amyloid-Induced Cortical Inflammation: Implications for Alzheimer's Disease
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2434
OP 2442
DO 10.1523/JNEUROSCI.22-07-02434.2002
VO 22
IS 7
A1 Michael T. Heneka
A1 Elena Galea
A1 Vitaliy Gavriluyk
A1 Lucia Dumitrescu-Ozimek
A1 JoAnna Daeschner
A1 M. Kerry O'Banion
A1 Guy Weinberg
A1 Thomas Klockgether
A1 Douglas L. Feinstein
YR 2002
UL http://www.jneurosci.org/content/22/7/2434.abstract
AB Degeneration of locus ceruleus (LC) neurons and reduced levels of norepinephrine (NE) in LC projection areas are well known features of Alzheimer's disease (AD); however, the consequences of those losses are not clear. Because inflammatory mediators contribute to AD pathogenesis and because NE can suppress inflammatory gene expression, we tested whether LC loss influenced the brain inflammatory gene expression elicited by amyloid β (Aβ). Adult rats were injected with the selective neurotoxinN-(2-chloroethyl)-N-ethyl-2 bromobenzylamine (DSP4) to induce LC death and subsequently injected in the cortex with Aβ (aggregated 1–42 peptide). DSP4 treatment potentiated the Aβ-dependent induction of inflammatory nitric oxide synthase (iNOS), interleukin (IL)-1β, and IL-6 expression compared with control animals. In contrast, the induction of cyclooxygenase-2 expression was not modified by DSP4 treatment. In control animals, injection of Aβ induced iNOS primarily in microglial cells, whereas in DSP4-treated animals, iNOS was localized to neurons, as is observed in AD brains. Injection of Aβ increased IL-1β expression initially in microglia and at later times in astrocytes, and expression levels were greater in DSP4-treated animals than in controls. The potentiating effects of DSP4 treatment on iNOS and IL-1β expression were attenuated by coinjection with NE or the β-adrenergic receptor agonist isoproterenol. These data demonstrate that LC loss and NE depletion augment inflammatory responses to Aβ and suggest that LC loss in AD is permissive for increased inflammation and neuronal cell death.